Farmasian tiedekunta


Recent Submissions

  • Dimitrow, Sari Maarit (Helsingin yliopisto, 2016)
    Development and Validation of a Drug-Related Problem Risk Assessment Tool for Use by Practical Nurses Working With Community-Dwelling Aged The demand for long-term home health care services for the aged (≥65 years) is growing. Practical nurses (PNs) are those who most often visit the aged using HC services and consequently, are in a key position to monitor the benefits and risks of pharmacotherapy of their clients. The aim of this study was to develop and validate an easy-to-use DRP Risk Assessment Tool (DRP-RAT) for PNs caring for home-dwelling aged ≥65 years focusing on identifying and solving the highest priority DRP risks. The specific aims were: 1) to systematically review articles that describe criteria for assessing inappropriate prescribing in the aged ≥65 years; 2) to describe the development process and content validation of the DRP-RAT; 3) to evaluate the feasibility of the final DRP-RAT among PNs in HC; and 4) to assess the reliability of risk assessments conducted by PNs by using DRP-RAT and to identify the clinically most significant DRPs needing action. Two systematic literature reviews (Study I, year 2010; an unpublished one) and the expertise of the research group were used as a basis for the development of the DRP-RAT. The content of the draft tool was validated by a three-round Delphi survey with a panel of 18 experts in geriatric care and pharmacotherapy (Study II, year 2010). Data for the feasibility study were collected during the training of PNs, working in HC, in the use of the DRP-RAT (Study III, year 2011). The PN-conducted (n=25) DRP risk assessments by DRP-RAT (n=85) and the same clients copied medication lists (n=68), face-to-face discussions and responses to open questions of the returned feedback forms (n=23) were analyzed. In 2013, an experienced geriatrician reviewed HC clients (n=45) medications by using three different reviewing methods on each patient (Study IV). The methods based on: 1) DRP-RAT (n=45) completed by the PNs (n=26) and copied medication lists; 2) health centre s medical records ( gold standard ); and 3) Methods 1 and 2 together. Results of the reviews and contents of the geriatrician s open comments regarding the PNsʼ risk assessments were analyzed. DRPs in the study population identified and reported by the geriatrician were studied from the geriatrician s DRP classifications (n=45) and by a retrospective review of the geriatrician s case reports (n=45). The final DRP-RAT consists of 18 items that assess risks for DRPs in home-dwelling clients. It is divided into four sections: 1) Basic Client Data, 2) Potential Risks for DRPs in Medication Use, 3) Characteristics of the Clientʼs Care and Adherence and, 4) Recommendations for Actions to Resolve DRPs. The DRP-RAT turned out to be feasible among PNs and the PN-completed tool was capable of providing reliable and timely patient information to support physician s clinical decision making. Compared to the gold standard (Method 2), Method 1 resulted in a false negative rating in 7% (95 % CI 1.4 18.3) of the cases (3/45). The geriatrician identified an average of 3.1 potential DRPs per patient. This study indicates that the DRP-RAT, developed and validated in this study, could make it possible to more effectively involve PNs, working in HC, in medication risk management among the home-dwelling aged, and that medication risk management should be focused on the highest priority risks. Actions to facilitate the implementation of the DRP-RAT in the Finnish health care system are needed. Future studies are needed to evaluate the effects of PNsʼ risk assessments using the DRP-RAT on clinical, humanistic and economic outcomes.
  • Kuryk, Lukasz (Helsingin yliopisto, 2016)
    Despite major advances in conventional cancer treatments by surgery, chemotherapy, radiotherapy and their combination, the outcome remains partially ineffective against numerous cancer types, for example mesothelioma, lung cancer, and colon cancer. Furthermore, due to resistance factors and the subsequent loss of response, which may occur rapidly during the conventional treatments regimes, new anti-cancer agents, presenting new mechanisms of action and lacking cross-resistance to commonly used therapies, are in high demand. Oncolytic virotherapy is a promising anti-cancer strategy, and the approval of the first oncolytic virus, Imlygic (T-Vec, talimogene laherparepvec), in Western world by US Food and Drug Administration (FDA) and European Medicines Agency (EMA) has opened up new perspectives for improved treatment of cancer. Single therapy is rarely successful in treating cancer, particularly in metastatic or advanced cancer, and survival rates with monotherapies alone are generally poor. The combination of multiple therapies to treat cancer has already shown significant results in the standard care of cancer. This strategy utilizes the combination of both conventional and novel therapies that can bring the future promise of cancer treatment. In this thesis it has been hypothesized that by combining oncolytic adenoviruses (oAd) with chemotherapeutic drugs and a biological agent we could improve anti-cancer efficacy through synergistic effect against cancer. Therefore, we have tested various treatment regimes with the overall goal being the improvement of oncolytic virotherapy efficacy. Secondly, since safety issues concerning gene therapy and viral vectors are tremendously important, we have performed studies on safety issues of adenoviral vectors. In brief, we have evaluated the anti-cancer activity of combination treatment with standard of care (SoC) chemotherapy (Pemetrexed, Cisplatin, Carboplatin) and Ad5/3-d24-GM-CSF (ONCOS-102) in vitro and in a xenograft BALB/c model of human malignant mesothelioma (MM). We could show improved anti-tumor effects when ONCOS-102 was combined with SoC chemotherapy regimens over chemotherapy and virus alone. Combination therapy resulted in synergistic anti-cancer effect improving the therapeutic outcome. In a subsequent study we tested anti-cancer properties of the dipeptide L-Carnosine complexed with an oncolytic adenovirus (virus-L-Carnosine complex). The complex demonstrated improved anti-tumor efficacy both in vitro and in vivo in tested cancer models. In HCT116 colon and A549 lung cancer cells, the virus-L-Carnosine complex presented a higher transduction level and infectious titer over uncoated oncolytic adenovirus. The in vivo efficacy of the virus-L-Carnosine complex was tested in two cancer models: i) lung and ii) colon cancer xenograft mice models. It exhibited a significant reduction in tumor growth compared to other tested groups. Additionally, we investigated the molecular mechanism underlying the effects of the complex on tumor growth reduction. Safety assessment of viral vectors was performed in animal studies. Extensive studies on toxicity and bio-distribution of ONCOS-102 in Syrian hamsters and experiments in BALB/c nude mice indicated no side effects of repeated administration of oncolytic adenovirus. The side effects were evaluated by assessment of body weight, food consumption, hematology, clinical chemistry, histopathology and bio-distribution. We concluded that combinatory studies utilizing oncolytic viruses with standard of care chemotherapy and an experimental virus-L-Carnosine complex showed synergistic anti-cancer efficacy, thus providing a strong rationale for clinical testing of such combinations in mesothelioma, lung and colon cancer. Additionally, our studies suggested that adenovirus could be used in future studies for delivery of other bioactive drugs as a novel strategy in cancer therapy.
  • Malinovskaja-Gomez, Kristina (Helsingin yliopisto, 2016)
    Biological variation and poor transport efficacy are the major concerns in the development of novel iontophoretic drug delivery systems for the transdermal administration of therapeutics. One possibility to overcome these limitations would be to load the drug in interest into a reservoir system such as ion-exchange fibers or nanocarriers prior administration. More precise and homogenous control of drug release and the following transdermal iontophoretic permeation could be obtained as the transdermal device/patch would determine the rate of drug transfer instead of the skin, leading to smaller inter- and intrasubject variability. In addition, the range of molecules delivered by iontophoresis can be expanded as charges could be imparted to neutral drugs by encapsulating them in charged drug carriers. Other benefits raising from such combined systems include enhanced drug transport into or across the skin, improved drug stability and decreased local side effects on skin. The aim of this thesis was to study in vitro the applicability of systems that combine iontophoresis and either drug-loaded ion-exchange fibers or nanocarriers for the controlled transdermal delivery of therapeutics. Firstly, drug reservoirs based on cation-exchange fibers were utilized to retard drug release and provide additional control into transdermal transport of a small molecular drug and a peptide. The drug release kinetics could be modified by the choice of the fiber type or the ionic composition of the external solution. The application of pulsed current iontophoresis instead of conventional constant current led to increased transport efficiency of a cationic hydrophobic peptide that has a tendency to adsorb into skin and inhibit electroosmosis as its main transport mechanism. In addition, drug delivery systems combining iontophoresis and nanoencapsulation into polymeric nanoparticles or lipid vesicles for the controlled transdermal delivery of lipophilic or hydrophilic model compound were developed and tested. Although the obtained nanocarriers were considered as suitable for transdermal iontophoretic administration, regarding the colloidal properties, stability and release kinetics, no clear advantage was observed with respect to drug permeation from free drug formulation. Throughout the thesis, the impact of formulation parameters and current type on drug transport efficiency was monitored. Iontophoretic transdermal drug delivery from polymeric nanoparticle-based formulations but not from lipid vesicular nanocarriers was improved by the application of pulsed current. In conclusion, binding the drug molecules prior iontophoresis into reservoir based on ion-exchange material or nanocarriers is a promising approach to be utilized in controlled transdermal delivery, although the comprehensive evaluation of full potential of such systems tailored for specific drug warrants further investigation in the future.
  • Lajunen, Tatu (Helsingin yliopisto, 2016)
    Biomolecules are emerging as the most important source of new therapeutic compounds. Commonly these molecules are fairly large and unstable in biological environment. Furthermore, the target sites are often located inside cells and specialized tissues. Nanoparticle based systems, including liposomes, have become the most studied method of biologics delivery. They increase drug stability in blood circulation and facilitates drug accumulation at the target site. However, often the amount of drug released remains insufficient. Lately, several stimuli-responsive nanoparticles have been developed for better control of the drug release. Among these are light triggered liposomes, which are the focus of this work. Liposomes consist of spherical bilayer forming lipids, phospholipids and sometimes additional stabilizers, such as cholesterol. The liposomes in this thesis were made with different manufacturing processes, among which the most common was the thin film hydration method. The size of the formed liposomes was reduced by extrusion, sonication or high pressure microfluidization. Light triggered release of cargo from the liposomes was achieved by encapsulating gold nanoparticles (AuNP) or indocyanine green (ICG), that convert light energy into heat. The produced heat affects the thermosensitive bilayer of the liposomes, making it more permeable for the drug molecules. The fluidity of the bilayer was analyzed to determine the optimal phospholipid composition. The size of the liposomes was measured by dynamic light scattering to evaluate the size reduction and uniformity. The stability of the different formulations was evaluated and compared with each other. Fluorescent molecules were used as model drug compounds to study the release properties of the liposomes in controlled in vitro and cell experiments. In this work, a large portfolio of methods and formulations was developed. By combining these properties into a single drug delivery system, efficient protection of the cargo and the healthy tissue, distribution to challenging target sites, controlled spatial and temporal drug release can be achieved. The next steps in this work involve evaluation of the optimized carrier with applicable disease models, analysis of the in vivo pharmacokinetics and more profound toxicological experiments. Even though many challenges remains to be solved, the beneficial qualities of the light triggered liposomes show great potential for treatment of posterior eye conditions, cancer and other diseases lacking in therapeutic efficacy.
  • Antila, Hanna (Helsingin yliopisto, 2016)
    Major depressive disorder is one of the most significant causes of disability worldwide. Currently, the main treatment options for depression are psychotherapy and antidepressant drugs that pharmacologically target the monoamine systems such as serotonin transporter (SERT) blocker fluoxetine. It has been hypothesized that impairments in synaptic function and plasticity, caused for example by stress, could underlie the manifestation of depression. Moreover, in rodent models chronic treatment with antidepressant drugs has been shown to enhance plasticity of the adult brain via brain-derived neurotrophic factor (BDNF). The effects of BDNF mediated via its receptor tropomyosin receptor kinase B (TrkB) promote synapse function and thus could facilitate recovery from depression. Interestingly, antidepressant drugs with different main pharmacological targets seem to share the ability to activate the TrkB receptor, however, the mechanisms how antidepressant drugs activate TrkB are not known. The delayed onset of action and limited therapeutic efficacy of antidepressant drugs has promoted interest toward finding more rapid-acting and effective treatment options for depression. Electroconvulsive therapy has been the treatment of choice for treatment resistant depressed patients, however, side effects and the disrepute among general public has limited its use. Recently, subanesthetic doses of dissociative anesthetic ketamine have been shown to rapidly alleviate depression symptoms in depressed patients who do not respond to conventional antidepressant drugs. The effects of ketamine on mood appear already couple of hours after single intravenous infusion and last for about one week. Ketamine has been shown to induce mammalian target of rapamycin (mTOR) via BDNF-TrkB signaling, rapidly promote synaptogenesis and alter neural network function. Furthermore, in small human studies another anesthetic isoflurane has rapidly alleviated symptoms of depressed patients. Yet, the potential of isoflurane in the treatment of depression has not been studied in large clinical trials. Since TrkB receptor is involved in regulation of synaptic plasticity, drugs that act as agonists or positive allosteric modulators of TrkB could be potentially beneficial in the treatment of CNS disorders characterized by impaired plasticity. The first aim of our studies was to develop a platform suitable for high-throughput screening of compounds regulating TrkB activity. We developed an in situ ELISA (enzyme-linked immunosorbent assay) method that detects phosphorylated TrkB receptors from cultured cells. The main advantage of the in situ ELISA compared to conventional ELISA is that the cells are cultivated directly on the ELISA plate making the additional transfer step of the cellular material from the cell culture plate to the ELISA plate unnecessary. To further validate the in situ ELISA method, we conducted a proof-of-concept screening of a small chemical library and found several compounds that dose-dependently activated TrkB receptor or inhibited BDNF-induced TrkB activation. The second aim was to examine the mechanism how the antidepressant drugs activate TrkB. Interestingly, we found that antidepressant drugs activate TrkB independently of BDNF. Moreover, SERT, the main pharmacological target of fluoxetine, was not required for the fluoxetine-induced TrkB activation. Furthermore, the antidepressant-induced TrkB activation was developmentally regulated. The ability of antidepressants to activate TrkB appeared around postnatal day 12. Interestingly, at this same developmental timepoint (P12) the ability of BDNF to activate TrkB decreased dramatically. Finally, we aimed to characterize the neurobiological basis for the possible antidepressant effects of isoflurane. We found that brief isoflurane anesthesia rapidly and transiently activated the TrkB-mTOR signaling and produced antidepressant-like behavioral response in the forced swim test in a TrkB-dependent manner. Single isoflurane treatment also produced an antidepressant-like phenotype in behavioral paradigms that normally require chronic treatment with conventional antidepressant drugs, suggesting that isoflurane may have rapid antidepressant effects similar to ketamine. Moreover, isoflurane facilitated hippocampal long-term potentiation when measured 24 hours after the treatment and affected the general neural network function by increasing activity of the parvalbumin-positive inhibitory interneurons in the hippocampus. In conclusion, our results improve the understanding of the mechanism of action of conventional antidepressant drugs and provide plausible neurobiological basis for the antidepressant effects of isoflurane. Our findings also support examining further the potential of anesthetics in the treatment of depressed patients who do not respond to the current treatment options.
  • Stepniewski, Michal (Helsingin yliopisto, 2016)
    The cell membrane is a gateway to the cell and immersion point for membrane proteins and thus is of interest for pharmacology and structural biology. This thesis aims to study its interaction with water, small molecules, polymers and proteins through molecular dynamics simulation and statistical analysis. In the first part of the thesis, I have performed a statistical analysis of membrane proteins present in the PDB databank and enumerated in a structure database of known membrane proteins. Based on a statistical analysis of 127 proteins it was shown that extracellular cysteines are not solvent accessible. This rule has not previously been stated and was poorly followed by the participants of the GPCR DOCK competitions in 2008 and 2010. Thus it can provide qualitative guidelines to improve structural modeling. In a second study, based on a statistical analysis of 39 membrane proteins of three or more transmembrane helices, all of different fold, we have shown and clustered different spatial arrangements that sets of three interacting or consecutive helices can take, in addition to visualizing their abundance. In the second part of the thesis, I performed 200 ns simulations of both membranes in the gel (DSPC) and liquid-crystalline (DLPC) states with solvent and ions; These simulations were repeated with functionalized PEG polymers included (PEGylation). We also performed 200ns lipid membrane simulations in the liquid-crystalline (POPC) state with hematoporphyrin. Our studies provide a new, more accurate description of interactions between lipid membrane ions and featuring PEG polymers rather as dynamic molecules looping around Na+ ions and penetrating to liquid crystalline membrane rather than just a steric barrier outside of membrane. This sheds new light on the mechanism of liposome protection by PEG as well as triggering the release of liposome content through a heat induced lipid phase transition. Hematoporphyrin was shown to reside in the lipid headgroup carbonyl region. Ionized hematoporphyrin has lower affinity to the membrane as well as forming stable dimers in the aqueous phase. The research was in agreement with experimental data and has provided a molecular level view of the interactions between photosensitizers and the membrane.
  • Kekäle, Meri (Helsingin yliopisto, 2016)
    The establishment of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of chronic myeloid leukemia (CML) during the last fifteen years. This study explored the journey of 86 patients with CML using oral TKI treatment in Finland. The aim was to assess their adherence to TKIs and how the adherence, which is crucial for treatment outcomes, could be improved. This study applied quantitative and qualitative methods and a randomized controlled study design during 2012-2014. All patients participated in the in-person interview, which followed the idea of the patient s journey with CML from the time before diagnosis to the study point. Patient-reported adherence was evaluated using Morisky s 8-Item Medication Adherence Scale (MMAS) (I-IV). Physicians were also asked to assess their patients adherence. Patient-reported adverse drug reactions (ADRs) and quality of life (QoL) were assessed during the interview using a structured questionnaire (II, III). The patient s knowledge of the disease and TKI treatment was evaluated by asking five key questions (I, III, IV). The intervention with 9-month follow-up in Study IV was based on tailored patient education combining nurse-conducted face-to-face counseling, educational video, patient booklet, website and text message reminders. The intervention material had the following learning objectives: CML as a disease, goals for TKI treatment, the importance of taking TKI medication as prescribed, and self-management of ADRs. A total of 86 patients participated in the study (approximately 20% of all Finnish CML patients). Of the patients enrolled, 43 were randomized into the intervention group and 43 into the control group (IV). A total of 68 patients completed the study. The results show that the response to TKI treatment was high (I), with 81% of the patients showing an optimal response to their treatment according to European LeukemiaNet 2013 recommendations. The CML patients knowledge of the disease and its treatment was poor (I). Despite the high molecular response rates to TKIs, adherence was not good in most of the patients: less than a quarter (23%) showed high adherence, 56% medium adherence, and 21% low adherence (I). Adherence was not influenced by patients gender, age, education, knowledge, time from diagnosis, ADRs, number of comorbidities or number of other medications. There was a considerable difference between observed and experienced adherence: 94% of the patients were highly adherent according to the physicians assessment, compared to 23% (I). The most common reason for unintentional non-adherence was forgetting to take the medication (I, III, IV). In the interviews patients reported self-regulation of medication taking, particularly on those occasions where patients wanted to avoid ADRs (III). The incidence of patient-reported ADRs was high (II). At the time of the study 97% of the patients reported suffering from at least one ADR, most commonly muscle soreness or cramp (80%), swelling of hands, legs, feet, or around the eyes (69%), and fatigue (50%). Patient interviews indicated that ADRs were the most common barriers to adherence (III). More than half of the patients felt the ADRs had a negative influence on their daily QoL (II). Compared with the total study group, the incidences of almost all symptoms were higher among patients whose symptoms negatively affected their daily life than those who reported no such influence (II). The patient journey model developed in the study (III) identified the following critical phases in the CML patient s journey: getting the diagnosis, starting the treatment, getting continuous support for treatment self-management, and managing fear caused by perceived severity of the disease. Even though only 44% of the low-adherent patients in the study experienced the TKI treatment as inconvenient, most of the patients (94%) were willing to stop taking the medication in the future if possible (III). All CML patients in the study were lacking a treatment plan and only a few had a medication list (I, III). The knowledge test (I, III) showed that patients had a poor understanding of their disease and its treatment, while low-adherent patients indicated that understanding the consequences of not taking the medication and the goal for the treatment would be motivating factors to adhere to the medication (III). The intervention significantly improved adherence (IV). In the intervention group the MMAS score increased more often than in the control group (p=0.001). The MMAS score declined in almost half of the patients in the control group, but only in 9% of those in the intervention group (p=0.001). A majority of the patients found the intervention useful, the most useful parts being face-to-face counseling and the educational booklet. Text messages were least valued. The findings of this study suggest that non-adherence is common among Finnish CML patients and that physicians seem to be too optimistic in assessing their patients adherence. The complex interplay between symptom burden, adherence, self-regulation, managing with ADRs, response to TKI therapy, and healthcare utilization highlights the need for regular symptom burden assessment in CML as a means to identify potential adherence problems before they affect the patients response to TKI treatment. Tailored patient education improved the adherence of patients with CML after a 9-month follow-up. Without the additional support, adherence behavior tended to decline. Patients were most satisfied with face-to-face counseling by the nurse, which means they need personal support and practical aids to help them manage their medication in everyday life. Access to personal counseling and information should be systematically planned as an essential part of CML care. Appropriate and updated information in printed and electronic formats should be available for nurses and other healthcare personnel to enable them to support their patients. The findings of this study suggest that patients perceptions and preferences should be understood and taken into account when designing patient education interventions for real-life clinical practice. The findings also highlight the need to further evaluate the interventions to enhance adherence. There is a need for communication to increase patients abilities to follow their treatment plan throughout their journey, which requires real partnership between healthcare professionals and patients.
  • Kopra, Jaakko (Helsingin yliopisto, 2016)
    Midbrain dopamine neurons exert a powerful influence on behavior and their dysfunction is associated with many neurological and neuropsychiatric diseases, including Parkinson s disease (PD). Dopamine neurons are large, complex and sensitive cells. Hence, their survival and correct function requires coordinated action of various transcription and regulatory factors both during development and aging. Potentially, one such factor is glial cell line-derived neurotrophic factor (GDNF). Ectopically applied GDNF is best known for its potent ability to protect and restore damaged dopaminergic neurons both in vitro and in vivo. GDNF-based therapies have been tested in clinical trials with PD patients with variable success. However, the function of endogenous GDNF in brain dopamine system development, aging and disease is poorly understood. Improvement in GDNF-based therapies requires better understanding of the physiological functions of GDNF in the brain. The current knowledge of endogenous GDNF function remains obscure, mainly due to the lack of proper animal models. The present study investigated the regulatory role of endogenous GDNF in the development, maintenance and function of midbrain dopamine neurons utilizing novel mouse models: GDNF conditional knock-out (cKO) mice and GDNF hypermorphic (GDNFh) mice over-expressing GDNF from the endogenous locus. GDNF cKO mice enable GDNF deletion solely from the central nervous system during embryonic development or later in adulthood, preserving its vital role in kidney development. Midbrain dopamine systems of these new mouse strains were studied with immunohistochemical, neurochemical, pharmacological, behavioral and molecular biology methods. We found more substantia nigra dopaminergic cells and elevated striatal dopamine levels in immature and adult GDNFh mice. In cKO mice, dopamine levels and cell numbers were unaltered, even upon aging, and regardless of the timing of GDNF deletion. Both mouse strains exhibited enhanced dopamine uptake, while responses to amphetamine were augmented in GDNFh mice and reduced in cKO mice. GDNFh mice also released more dopamine and GDNF elevation protected them in a lactacystin-based model of PD. Overall, dopamine neurons were more sensitive to moderate elevation than complete absence of endogenous GDNF, which suggests that they can adaptively compensate for GDNF loss. This highlights the limitation of broadly utilized gene deletion approaches in analyzing gene function. Our results indicate a clear role for endogenous GDNF in midbrain dopamine neuron development and function, but also demonstrate that GDNF is not required for their maintenance during aging. Furthermore, the ability of endogenous GDNF to protect animals in a PD model without the side effects associated with ectopic GDNF application suggests that elevation in endogenous GDNF levels may be an important future route for PD therapy.
  • Svanbäck, Sami (Helsingin yliopisto, 2016)
    Key physicochemical properties determining the developability of a drug include solubility, dissolution rate, lipophilicity and pKa. Not only do these properties affect synthesis and solid form optimization, choice of administration route, processability and formulation strategies; they also greatly influence, directly or indirectly, the absorption, distribution, metabolism, excretion, toxicity and efficacy of drugs. However, miniaturized methods that would enable small-scale determination of these fundamental properties in an accurate and rapid way, are lacking. Image-based microscopy could provide an opportune method for non-specific, rapid and miniaturized applications. First, the applicability of image-based microscopy and single-particle analysis in drug dissolution rate measurement was evaluated. This was done by comparing image analysis data with traditional UV spectrophotometric data of individual dissolving drug pellets. It was found that dissolution rates obtained by image analysis and UV spectrophotometry were practically identical. Next, a single-particle trap flow-through device was developed, wherein it is possible to continuously monitor individual drug particles under constant flow conditions. Based on the promising results of image-based dissolution rate analysis, the possibility of acquiring the intrinsic dissolution rate from individual freely rotating particles, trapped inside the flow through device, was evaluated. It was found that image analysis can be used for rapid real-time determination of intrinsic dissolution rates from continuously changing effective surface areas of dissolving individual micro-particles. The method was then further extended to determine the equilibrium solubility of drugs. Based on the diffusion layer dissolution rate model, solubility is the rate limiting factor of dissolution and can therefore be determined. While solubility is generally determined from bulk solutions after long incubation times, it was shown that the equilibrium solubility can be rapidly determined from individual pure-substance particles by means of the diffusion layer theory and image analysis. Finally, the single-particle method was further miniaturized and a second device developed, in order to allow imaging of individual powder crystals. It was shown that dissolution rate and solubility can be acquired from individual nanogram crystals. The single-particle method was further extended to acquire pKa, logP and logD of the studied substances, using aqueous buffers, simulated physiological solutions and organic solvents. Using this method and device, it is possible to acquire a complete pH-solubility profile for an unknown material of unknown composition, with individual measurements of less than 30 seconds. In summary, these results strongly suggest that image-based analysis of materials could be applied in high-throughput experimentation (HTE) applications. The possibility of acquiring solubility, dissolution rate, lipophilicity and pKa using a single analytical method, could significantly simplify and speed up accurate data acquisition. This in turn, could lead to faster and more informed decision-making and, ultimately, better and more affordable drugs.
  • Borrel, Alexandre (Helsingin yliopisto, 2016)
    This thesis presents the development of computational methods and tools using as input three-dimensional structures data of protein-ligand complexes. The tools are useful to mine, profile and predict data from protein-ligand complexes to improve the modeling and the understanding of the protein-ligand recognition. This thesis is divided into five sub-projects. In addition, unpublished results about positioning water molecules in binding pockets are also presented. I developed a statistical model, PockDrug, which combines three properties (hydrophobicity, geometry and aromaticity) to predict the druggability of protein pockets, with results that are not dependent on the pocket estimation methods. The performance of pockets estimated on apo or holo proteins is better than that previously reported in the literature (Publication I). PockDrug is made available through a web server, PockDrug-Server (, which additionally includes many tools for protein pocket analysis and characterization (Publication II). I developed a customizable computational workflow based on the superimposition of homologous proteins to mine the structural replacements of functional groups in the Protein Data Bank (PDB). Applied to phosphate groups, we identified a surprisingly high number of phosphate non-polar replacements as well as some mechanisms allowing positively charged replacements. In addition, we observed that ligands adopted a U-shape conformation at nucleotide binding pockets across phylogenetically unrelated proteins (Publication III). I investigated the prevalence of salt bridges at protein-ligand complexes in the PDB for five basic functional groups. The prevalence ranges from around 70% for guanidinium to 16% for tertiary ammonium cations, in this latter case appearing to be connected to a smaller volume available for interacting groups. In the absence of strong carboxylate-mediated salt bridges, the environment around the basic functional groups studied appeared enriched in functional groups with acidic properties such as hydroxyl, phenol groups or water molecules (Publication IV). I developed a tool that allows the analysis of binding poses obtained by docking. The tool compares a set of docked ligands to a reference bound ligand (may be different molecule) and provides a graphic output that plots the shape overlap and a Jaccard score based on comparison of molecular interaction fingerprints. The tool was applied to analyse the docking poses of active ligands at the orexin-1 and orexin-2 receptors found as a result of a combined virtual and experimental screen (Publication V). The review of literature focusses on protein-ligand recognition, presenting different concepts and current challenges in drug discovery.
  • Kanninen, Liisa (Helsingin yliopisto, 2016)
    Standard two-dimensional (2D) in vitro cell culture systems do not mimic the complexity found in the liver as three-dimensional (3D) cell-cell and cell-matrix interactions are missing. Although the concept of cell culturing was established over 100 years ago the currently used culture techniques are not yet ideal. In the field of pharmacy especially, the need of physiologically-relevant models to characterize biotransformation pathways during drug development is urgent. Hepatocytes, the main cell type of the liver, are essential components in these in vitro models. Liver cell lines and derivation of hepatocyte-like cells from stem cells are alternative sources to primary isolations for obtaining hepatocytes. In the liver, hepatocytes are in continuous interaction with other cells and surrounding extracellular matrix (ECM). Moreover, liver functions are strictly dependent on correct tissue architecture. One approach to improve the standard cell culture systems is to mimic the hepatocytes natural microenvironment and organization by culturing the cells within biomaterial matrices. Matrix-based culture systems for hepatocytes have been developed from natural, synthetic and hybrid biomaterials and the cells can be grown in 2D or 3D configuration. The aim of this thesis was to find new defined culture matrices for in vitro hepatic differentiation. First, we studied two biomaterials, nanofibrillar cellulose (NFC) hydrogel and hyaluronic acid-gelatin (HG) hydrogel, to construct functional liver 3D organoids. Both of the studied hydrogels supported 3D spheroid organization of human liver progenitor HepaRG cells and their functional polarization. The 3D culture systems promoted hepatic differentiation of progenitor cells faster than the standard 2D culture. However, the 3D hydrogels did not enhance hepatocyte-like properties if the HepaRG cells were pre-differentiated to hepatocyte-like cells in advance. Subsequently, we showed that NFC hydrogel culture can be combined with high-resolution imaging since the intact spheroids can be enzymatically released from the matrix. This was not possible with the HG hydrogel. We demonstrated that silica bioreplication preserved the 3D spheroid structure with its fine details and cellular antigens and allowed detailed morphological analysis of the spheroids cultured in NFC hydrogel. Next, we developed a xeno-free matrix for hepatic specification of human pluripotent stem cell-derived definite endoderm (DE) cells using a three-step approach. We first proved our hypothesis that a liver progenitor-like matrix, HepaRG-derived acellular matrix (ACM), supports hepatic lineage differentiation of DE cells. Then, we characterized the ECM proteins secreted by HepaRG cells, and finally we showed that the identified proteins, laminin-511 and laminin-521, can replicate the effect of HepaRG-ACM. The human pluripotent stem cell-derived hepatic cells expressed mature hepatocyte-like functions but the phenotype of the cells was eventually closer to fetal hepatocytes than mature cells. Thus, hepatic maturation should be further studied. In conclusion, this thesis describes new biomaterials for hepatic differentiation, a protocol to form 3D spheroids and to transfer intact spheroids to high-resolution imaging, and that the described three-step approach can guide the identification of new defined matrices.
  • Herranz Blanco, Bárbara (Helsingin yliopisto, 2016)
    Drug delivery systems (DDS) have been developed in the last decades to improve the pharmacological properties of free drugs by modifying their pharmacokinetic profile and biodistribution. Major limitations for newly developed drug molecules are the poor water solubility and stability, which can be addressed by DDS. These can protect the drugs from the potentially harsh external conditions found in the biological fluids, and improve their dissolution rate by different strategies, overall increasing the therapeutic activity of the drugs. Additionally, chemotherapeutic agents are nonspecific in nature, leading to deleterious off-target side effects, and poor therapeutic efficacy. Therefore, targeted therapy plays a very important role in cancer treatment, although not without obstacles, since DDS have to overcome a number of biological barriers following their intravenous administration, including renal clearance or opsonization-mediated phagocytosis and efficient extravasation to the tumor. Mesoporous silicon (PSi) micro- and nanoparticles offer numerous benefits for biomedical applications, in particular for drug delivery. Along with a great biocompatibility and biodegradability, PSi possess mesopores (2‒50 nm), where the drugs can be easily loaded and confined in their amorphous state avoiding extensive crystallization, thus, increasing their dissolution rate. However, the release of drugs from this platform is uncontrolled and fast, necessitating the use of strategies to tune the drug release. In this thesis, multiple approaches were used for the design and fabrication of hybrid composites for drug delivery and cancer therapy, including PSi and polymer‒drug conjugate-based DDS produced by different modalities of the microfluidics technology and pH-switch nanoprecipitation. First, the loading and release of drugs with different solubility characteristics from PSi were investigated, and further PSi-lipid and polymer-composites were developed to control the drug release profiles. Overall, it was achieved both a sustained release of hydrophilic and hydrophobic molecules loaded on the PSi and also a reduced initial burst release from the bare PSi particles. Next, PSi-based nanovectors were envisaged for antitumoral applications. A smart PSi-based hybrid nanocomposite with stealth properties was developed, consisting of a pH-responsive polymeric structure assembled on the surface of drug-loaded PSi nanoparticles. This nanocomposite was extremely efficient avoiding drug release from PSi under physiological conditions, while allowing the release of the drug upon acidification of the medium. Remarkably, the nanocomposites avoided extensive macrophage recognition and phagocytosis. Thereupon, a tumor targeted theranostic nanoplatform with dual pH- and magnetic-response capacity was designed. The DDS consisted of a polymeric-drug conjugate nanoparticle containing an imaging agent and decorated with a tumor homing peptide for targeted drug delivery, which was successfully applied for intracellular triggered drug release. Overall, the hybrid composites based on PSi and a polymer-drug conjugate represented an advanced contribution to the field of drug delivery and cancer therapy, and in particular to the development of PSi as a platform for advanced drug delivery applications.
  • Shrestha, Neha (Helsingin yliopisto, 2016)
    Regardless of the considerable efforts, there have been no major breakthroughs in the development of effective oral protein/peptide delivery. When compared to parenteral administration, oral delivery can significantly improve the patients quality of life, especially in chronic conditions, such as diabetes mellitus (DM), which requires multiple injections daily. However, oral absorption of proteins/peptides is severely limited by their physico-chemical properties and various physiological barriers in the gastrointestinal tract. Porous silicon (PSi) has emerged as a promising drug delivery system, owing to its beneficial properties, such as top-down production, customizable particle and pore morphology, easy surface modification, simple drug loading, biodegradability and biocompatibility. Thus, the aim of this dissertation was to develop a multifunctional PSi based platforms that would be able to overcome the physiological barriers and efficiently deliver insulin and glucagon-like peptide-1 (GLP-1) orally. First, the influence of different PSi surface chemistries was evaluated on the intestinal transport of insulin. Due to the negatively charged surface of PSi, there was minimal interactions with the intestinal cells. Thus, chitosan, a polycationic mucoadhesive biopolymer with permeation enhancing effect, was used to modify the surface of the PSi microparticles. When comparing different surface modification techniques, chemical conjugation of chitosan to PSi exhibited strongest cellular interaction, and the highest insulin permeation and uptake across the intestinal cell monolayers. Secondly, three different nanoparticles (NPs) were developed based on lipids, polymers and PSi, with and without chitosan coating, and evaluated as potential oral GLP-1 delivery system. The results showed that the chitosan-modified PSi NPs were the most efficient nanosystem with the best loading degree and the highest GLP-1 permeation across the cellular monolayer. To overcome several physiological barriers, the next step was to develop a multistage nanocomposite comprising of chitosan-conjugated PSi NPs that were coated with a pH responsive polymer, in order to deliver GLP-1 and dipeptidylpeptidase-4 (DPP4) inhibitor simultaneously via the oral route. This multistage nanosystem showed enhanced GLP-1 transport across the intestinal cell monolayers and across the rat intestinal tissue. Furthermore, the nanosystem also demonstrated hypoglycemic effect in vivo after the oral administration in diabetic rats. The efficacy of the nanosystem could be attributed to the combined effect of the permeation enhancing chitosan-modified PSi NPs, the presence of DPP4 inhibitor that prevented GLP-1 degradation, and the pH responsive coating that helped in avoiding premature GLP-1 release/degradation in the stomach. Moreover, it was shown that the mucoadhesivity and permeation enhancing ability of chitosan-modified PSi NPs could be significantly increased by further surface modification of NPs with either L-cysteine or cell-penetrating peptide (CPP). It was disclosed that electrostatic interactions between the NPs and the glycocalyx were the most prominent pathway for the transport and uptake of insulin from the NPs, together with the contribution of active transport, adsorptive endocytosis and clathrin-mediated endocytosis. Overall, advanced PSi-based systems were developed which successfully overcame several limitations associated with the oral delivery of biomacromolecules, and thus, showed high clinical potential as oral protein/peptide delivery systems for DM therapy
  • Hirvinen, Mari (Helsingin yliopisto, 2016)
    Cancer is the leading cause of death worldwide creating a need for novel cancer treatments that are more efficient but also safer and more specific. Oncolytic viruses (OVs) have shown a solid safety profile in clinical trials. OVs are nowadays considered immunotherapies because of to their ability to stimulate the host immune system to fight against cancer. Promising efficacy has been seen in some trials, however, efficacy is often seen only in a small group of patients. The purpose of the thesis was to improve the efficacy of OV therapies by boosting the immunogenicity of the viruses, and to optimize the therapeutic efficacy by selecting favorable patient populations and by developing a method to tailor the drug individually for each patient. In the first study, an oncolytic adenovirus (OAd) was modified to express human tumor necrosis factor alpha (hTNFα), a potent immunomodulatory cytokine. The TNFα-virus showed effective tumor cell killing associated with signs of immunogenic cell death and enhanced recruitment of immune cells to the infection site. We also saw potential for combining the TNFα-virus therapy with radiation. In another study the immunogenicity of an oncolytic vaccinia virus was enhanced by modifying it to express DNA-dependent activator of interferon-regulatory factors (DAI), a potent inducer of innate immune responses during virus infection. We showed that the DAI-virus induces expression of genes involved in immune responses, and treatments with the virus showed improved cancer-killing efficacy and immunogenicity in murine and human melanoma models, suggesting applicability also in vaccine design. Response rates after virotherapies vary between patients, and there is a lack of markers that would help predict the patient cohorts who would benefit from the therapy. We screened over 200 cancer patients treated with OAds for two Fc gamma receptor (FcγR) polymorphisms to determine if these polymorphisms would affect the responsiveness to the treatments. We observed a certain FcγR genotype combination (FcγRIIIa-VV + FcγRIIa-HR) to be predictive of poor overall survival after OAd treatments. To tailor the OV therapy for enhanced specificity, we developed a novel platform (PeptiCRAd) to coat a virus with tumor-specific antigens (peptides) for improved induction of cancer-specific immunity. Efficacy and immunogenic potency of the PeptiCRAd were shown in several in vivo models. Our results suggest that administration of tumor-specific peptides on the surface of OVs increases the anti-tumor efficacy compared to treatments with viruses or peptides alone. This platform has potential to be used as a carrier and adjuvant for patient-specific peptides to trigger anti-tumor immunity in a personalized manner.
  • Montalvão, Sofia (Helsingin yliopisto, 2016)
    Marine environment is prolific in organisms with unique properties. Seas and oceans contain a wide diversity of species with biologically active metabolites that represent a valuable source with great potential for the development of novel therapeutic agents. This dissertation is focused on the biological study of synthetic compounds based on marine scaffolds as well as on marine natural product extracts originating from the Aegean Sea. Furthermore, it offers an introduction on the importance of marine natural products in the search of new bioactive compounds, the use of natural products as scaffolds for the synthesis of new drugs, and a general overview on bioactivity screening and the current status of marine-derived bioactive compounds as therapeutic agents. The potential of oroidin and clathrodin as parent structures for synthesis of novel compounds was explored. Antimicrobial and antiproliferative studies were conducted and it was concluded that 4-phenyl-2-aminoimidazoles 6g(I) and 6h(I) showed the best antimicrobial effect against Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), while compound 6j(I) showed the most interesting IC50 in antiproliferative studies. Compound 7(II), a synthetic derivative of 2-aminobenzothiazole, showed IC50 of 16 μM and 71 μM against a cancer cell line and a normal cell line, respectively. The selectivity index showed selectivity towards cancerous cells. In addition, okadaic acid was used as inspiration for the synthesis of crown ether acyl compounds. Compound (1,4,7,10,13,16-hexaoxacyclooctadecan-2-yl)methyl 3-(pyren-1-yl)propanoate) 1o(III) was found to be the most active in antimicrobial studies against Gram-positive Staphylococcus aureus with a MIC50 of 7.2 μM. The importance of bioprospecting the rich marine biodiversity in the Aegean Sea was also studied in this thesis. Biological activities of extracts from cyanobacteria, micro- and macroalgae were evaluated, and microalgae extracts (Amphora cf capitellata and Nitzschia communis) showed the most interesting antimicrobial results against Staphylococcus aureus and fungus Candida albicans. The results of the biological studies conducted in this thesis demonstrated antimicrobial and antiproliferative activity of several marine natural products and their synthetic derivatives. Further studies and structural optimization should be done to fully explore their potential for the development of therapeutic agents.