Browsing by Subject "SMALL-MOLECULE"

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  • Kuusanmäki, Heikki; Dufva, Olli; Parri, Elina; van Adrichem, Arjan J.; Rajala, Hanna; Majumder, Muntasir M.; Yadav, Bhagwan; Parsons, Alun; Chan, Wing C.; Wennerberg, Krister; Mustjoki, Satu; Heckman, Caroline A. (2017)
    Constitutive JAK/STAT3 signaling contributes to disease progression in many lymphoproliferative disorders. Recent genetic analyses have revealed gain-of-function STAT3 mutations in lymphoid cancers leading to hyperactivation of STAT3, which may represent a potential therapeutic target. Using a functional reporter assay, we screened 306 compounds with selective activity against various target molecules to identify drugs capable of inhibiting the cellular activity of STAT3. Top hits were further validated with additional models including STAT3-mutated natural killer (NK)-cell leukemia/lymphoma cell lines and primary large granular lymphocytic (LGL) leukemia cells to assess their ability to inhibit STAT3 phosphorylation and STAT3 dependent cell viability. We identified JAK, mTOR, Hsp90 and CDK inhibitors as potent inhibitors of both WT and mutant STAT3 activity. The Hsp90 inhibitor luminespib was highly effective at reducing the viability of mutant STAT3 NK cell lines and LGL leukemia patient samples. Luminespib decreased the phosphorylation of mutant STAT3 at Y705, whereas JAK1/JAK2 inhibitor ruxolitinib had reduced efficacy on mutant STAT3 phosphorylation. Additionally, combinations involving Hsp90, JAK and mTOR inhibitors were more effective at reducing cell viability than single agents. Our findings show alternative approaches to inhibit STAT3 activity and suggest Hsp90 as a therapeutic target in lymphoproliferative disorders with constitutively active STAT3.
  • Balasubramanian, Vimalkumar; Domanskyi, Andrii; Renko, Juho-Matti; Sarparanta, Mirkka; Wang, Chang-Fang; Rebelo Correia, Alexandra Maria; Mäkilä, Ermei; Alanen, Osku; Salonen, Jarno; Airaksinen, Anu; Tuominen, Raimo K.; Hirvonen, Jouni; Airavaara, Mikko; Santos, Hélder A. (2020)
    Generation of new neurons by utilizing the regenerative potential of adult neural stem cells (NSCs) and neuroblasts is an emerging therapeutic strategy to treat various neurodegenerative diseases, including neuronal loss after stroke. Committed to neuronal lineages, neuroblasts are differentiated from NSCs and have a lower proliferation rate. In stroke the proliferation of the neuroblasts in the neurogenic areas is increased, but the limiting factor for regeneration is the poor survival of migrating neuroblasts. Survival of neuroblasts can be promoted by small molecules; however, new drug delivery methods are needed to specifically target these cells. Herein, to achieve specific targeting, we have engineered biofunctionalized porous silicon nanoparticles (PSi NPs) conjugated with a specific antibody against polysialylated neural cell adhesion molecule (PSA-NCAM). The PSi NPs loaded with a small molecule drug, SC-79, were able to increase the activity of the Akt signaling pathway in doublecortin positive neuroblasts both in cultured cells and in vivo in the rat brain. This study opens up new possibilities to target drug effects to migrating neuroblasts and facilitate differentiation, maturation and survival of developing neurons. The conjugated PSi NPs are a novel tool for future studies to develop new therapeutic strategies aiming at regenerating functional neurocircuitry after stoke.
  • Ravikumar, Balaguru; Aittokallio, Tero (2018)
    Introduction: Polypharmacology has emerged as an essential paradigm for modern drug discovery process. Multiple lines of evidence suggest that agents capable of modulating multiple targets in a selective manner may offer also improved balance between therapeutic efficacy and safety compared to single-targeted agents. Areas covered: Herein, the authors review the recent progress made in experimental and computational strategies for addressing the critical challenges with rational discovery of selective multi-targeted agents within the context of polypharmacological modelling. Specific focus is placed on multi-targeted mono-therapies, although examples of combinatorial polytherapies are also covered as an important part of the polypharmacology paradigm. The authors focus mainly on anti-cancer treatment applications, where polypharmacology is playing a key role in determining the efficacy-toxicity trade-off of multi-targeting strategies. Expert opinion: Even though it is widely appreciated that complex polypharmacological interactions can contribute both to therapeutic and adverse side-effects, systematic approaches for improving this balance by means of integrated experimental-computational strategies are still lacking. Future developments will be needed for comprehensive collection and harmonization of systems-wide target selectivity data, enabling better utilization and control for multi-targeted activities in the drug development process. Additional areas of future developments include model-based strategies for drug combination screening and improved pre-clinical validation options with animal models.
  • Zimmer, Jutta; Tacconi, Eliana M. C.; Folio, Cecilia; Badie, Sophie; Porru, Manuela; Klare, Kerstin; Tumiati, Manuela; Markkanen, Enni; Halder, Swagata; Ryan, Anderson; Jackson, Stephen P.; Ramadan, Kristijan; Kuznetsov, Sergey G.; Biroccio, Annamaria; Sale, Julian E.; Tarsounas, Madalena (2016)
    G-quadruplex (G4)-forming genomic sequences, including telomeres, represent natural replication fork barriers. Stalled replication forks can be stabilized and restarted by homologous recombination (HR), which also repairs DNA double-strand breaks (DSBs) arising at collapsed forks. We have previously shown that HR facilitates telomere replication. Here, we demonstrate that the replication efficiency of guanine-rich (G-rich) telomeric repeats is decreased significantly in cells lacking HR. Treatment with the G4-stabilizing compound pyridostatin (PDS) increases telomere fragility in BRCA2-deficient cells, suggesting that G4 formation drives telomere instability. Remarkably, PDS reduces proliferation of HR-defective cells by inducing DSB accumulation, checkpoint activation, and deregulated G2/M progression and by enhancing the replication defect intrinsic to HR deficiency. PDS toxicity extends to HR-defective cells that have acquired olaparib resistance through loss of 53BP1 or REV7. Altogether, these results highlight the therapeutic potential of G4-stabilizing drugs to selectively eliminate HR-compromised cells and tumors, including those resistant to PARP inhibition.