Daclatasvir, an Antiviral Drug, Downregulates Tribbles 2 Pseudokinase and Resensitizes Enzalutamide-Resistant Prostate Cancer Cells.

FDA-approved enzalutamide is commonly prescribed to reduce the growth of advanced prostate cancer by blocking androgen receptor function. However, enzalutamide-resistant prostate cancer (ERPC) invariably develops and progresses to metastatic, lethal disease. Management of ERPC poses a special problem not only because available therapeutic regimens cannot effectively kill ERPC cells but also due to their propensity to invade large bones. Moreover, molecular mechanism(s) behind enzalutamide resistance is not properly understood, which is delaying development of newer agents. We found that the pseudokinase, Tribbles 2 (TRIB2), is overexpressed in ERPC cells and plays a critical role in their survival. Forced overexpression of TRIB2 enhances prostate cancer cell growth and confers resistance to physiologic doses of enzalutamide, suggesting that TRIB2 plays an important role in the development and progression of ERPC. Though TRIB2 has emerged as an excellent molecular target for ERPC, suitable inhibitors are not commercially available for effective targeting. By designing a luciferase-tagged TRIB2 fusion protein-based assay system, we screened a library of about 1,600 compounds and found that daclatasvir (DCV), an antiviral drug, effectively inhibits TRIB2-luciferase. We also found that DCV degrades TRIB2 proteins by direct binding and resensitizes ERPC cells to enzalutamide treatment. Moreover, DCV at lower, sublethal doses synergizes with enzalutamide to decrease the viability and induce apoptosis in prostate cancer cells. Because DCV is already approved by the FDA and well tolerated in humans, based on our findings, it appears that DCV is a promising new agent for development of an effective therapy for advanced, enzalutamide-resistant, lethal prostate cancer.

A systematic review of GWAS identified SNPs associated with outcomes of medications for opioid use disorder.

BACKGROUND: Patients with opioid use disorder (OUD) display an interindividual variability in their response to medications for opioid use disorder (MOUD). A genetic basis may explain the variability in this response. However, no consensus has been reached regarding which genetic variants significantly contribute to MOUD outcomes. OBJECTIVES: This systematic review aims to summarize genome-wide significant findings on MOUD outcomes and critically appraise the quality of the studies involved. METHODS: Databases searched from inception until August 21st, 2020 include: MEDLINE, Web of Science, EMBASE, CINAHL and Pre-CINAHL, GWAS Catalog and GWAS Central. The included studies had to be GWASs that assessed MOUD in an OUD population. All studies were screened in duplicate. The quality of the included studies was scored and assessed using the Q-Genie tool. Quantitative analysis, as planned in the protocol, was not feasible, so the studies were analyzed qualitatively. RESULTS: Our search identified 7292 studies. Five studies meeting the eligibility criteria were included. However, only three studies reported results that met our significance threshold of p ≤ 1.0 × 10-7. In total, 43 genetic variants were identified. Variants corresponding to CNIH3 were reported to be associated with daily heroin injection in Europeans, OPRM1, TRIB2, and ZNF146 with methadone dose in African Americans, EYS with methadone dose in Europeans, and SPON1 and intergenic regions in chromosomes 9 and 3 with plasma concentrations of S-methadone, R-methadone, and R-EDDP, respectively, in Han Chinese. LIMITATIONS: The limitations of this study include not being able to synthesize the data in a quantitative way and a conservative eligibility and data collection model. CONCLUSION: The results from this systematic review will aid in highlighting significant genetic variants that can be replicated in future OUD pharmacogenetics research to ascertain their role in patient-specific MOUD outcomes. Systematic review registration number CRD42020169121.

Immunokinases, a novel class of immunotherapeutics for targeted cancer therapy.

Certain characteristics of tumor cells make it possible to develop rational strategies for targeting tumors without harming normal cells. These include the presence of cell surface molecules that characterize the current state of the tumor (e.g. CD30 on Hodgkin lymphoma cells) and the genetic and epigenetic changes that activate oncogenes and inactivate tumor suppressor genes (e.g. the inactivation of tumor suppressor gene DAPK2 in Hodgkin lymphoma cells, which blocks apoptosis). We have developed a novel tumor-targeting fusion protein by combining a selective ligand (CD30L) with a constitutively active version of DAPK2 (DAPK2'-CD30L), thus increasing tumor specificity and reducing systemic toxicity. We showed that this immunokinase fusion protein induces apoptosis specifically in CD30(+)/DAPK2(-) tumor cells in vitro and significantly prolonged overall survival in a disseminated Hodgkin lymphoma xenograft SCID mouse model. Therapeutic strategies based on the cell-specific restoration of a defective, tumor-suppressing kinase demonstrate the feasibility of targeted therapy using recombinant immunokinases.

The role of calcium and calcium/calmodulin-dependent kinases in skeletal muscle plasticity and mitochondrial biogenesis.

Intracellular Ca(2+) plays an important role in skeletal muscle excitation-contraction coupling and also in excitation-transcription coupling. Activity-dependent alterations in muscle gene expression as a result of increased load (i.e. resistance or endurance training) or decreased activity (i.e. immobilization or injury) are tightly linked to the level of muscle excitation. Differential expression of genes in slow- and fast-twitch fibres is also dependent on fibre activation. Both these biological phenomena are, therefore, tightly linked to the amplitude and duration of the Ca(2+) transient, a signal decoded downstream by Ca(2+)-dependent transcriptional pathways. Evidence is mounting that the calcineurin-nuclear factor of activated T-cells pathway and the Ca(2+)/calmodulin-dependent kinases (CaMK) II and IV play important roles in regulating oxidative enzyme expression, mitochondrial biogenesis and expression of fibre-type specific myofibrillar proteins. CaMKII is known to decode frequency-dependent information and is activated during hypertrophic growth and endurance adaptations. Thus, it was hypothesized that CaMKII, and possibly CaMKIV, are down regulated during muscle atrophy and levels of expression of CaMKII alpha, -II beta, -II gamma and -IV were assessed in skeletal muscles from young, aged and denervated rats. The results indicate that CaMKII gamma, but not CaMKIIalpha or -beta, is up regulated in aged and denervated soleus muscle and that CaMKIV is absent in skeletal but not cardiac muscle. Whether CaMKII gamma up-regulation is part of the pathology of wasting or a result of some adaptational response to atrophy is not known. Future studies will be important in determining whether insights from the adaptational response of muscle to increased loads will provide pharmacological approaches for increasing muscle strength or endurance to counter muscle wasting.

Ziskind-Somerfeld Research Award. Protein kinase C signaling in the brain: molecular transduction of mood stabilization in the treatment of manic-depressive illness.

Understanding the biology of the pharmacological stabilization of mood will undoubtedly serve to provide significant insight into the pathophysiology of manic-depressive illness (MDI). Accumulating evidence from our laboratories and those of other researchers has identified the family of protein kinase C isozymes as a shared target in the brain for the long-term action of both lithium and valproate. In rats chronically treated with lithium, there is a reduction in the hippocampus of the expression of two protein kinase isozymes, alpha and epsilon, as well as a reduction in the expression of a major PKC substrate, MARCKS, which has been implicated in long-term neuroplastic events in the developing and adult brain. In addition, we have been investigating the down-stream impact of these mood stabilizers on another kinase system, GSK-3 beta and on the AP-1 family of transcription factors. Further studies have generated promising preliminary data in support of the antimanic action of tamoxifen, and antiestrogen that is also a PKC inhibitor. Future studies must address the therapeutic relevance of these protein targets in the brain using innovative strategies in both animal and clinical investigations to ultimately create opportunities for the discovery of the next generations of mood stabilizers for the treatment of MDI.