GSK-3: An "Ace" Among Kinases.

Background: Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase known to be participating in the regulation of ß-catenin signaling (Wnt signaling). They help in the establishment of a multicomponent destruction complex that stimulates phosphorylation, leading to the destruction of ß-catenin. Evidence about the role of increasingly active ß-catenin signaling is involved in many forms of human cancer. The understanding of GSK-3 remains elusive as recent research aims to focus on developing potent GSK-3 inhibitors to target this kinase. Objective: This short review aims to highlight the regulation of GSK-3 with emphasis on Wnt signaling while highlighting its interaction with miRNAs corresponding to pluripotency and epithelial mesenchymal transition substantiating this kinase as an "Ace" among kinases in regulation of cellular processes. Result: Significant findings of miRNA regulation by GSK-3 exemplify the underpinnings of kinase-mediated transcriptional regulation in cancers. Conclusion: The review provides evidence on the role of GSK-3 as a possible master regulator of proteins and noncoding RNA, thereby implicating the fate of a cell.

REV-ERB is essential in cardiac fibroblasts homeostasis.

REV-ERB agonists have shown antifibrotic effects in the heart and other organs. The function of REV-ERB in the cardiac fibroblasts remains unstudied. Here, we characterize the functional difference of REV-ERB in mouse embryonic fibroblasts and cardiac fibroblasts using genetic deletion of REV-ERBα and ß in vitro. We show that REV-ERB α/ß double deleted cardiac fibroblasts have reduced viability and proliferation, but increased migration and myofibroblasts activation. Thus, REV-ERB α/ß has essential cell-autonomous role in cardiac fibroblasts in maintaining them in a healthy, quiescent state. We also show that existing REV-ERB agonist SR9009 strongly suppresses cardiac fibroblasts activation but in a REV-ERB-independent manner highlighting the need to develop novel REV-ERB agonists for treating cardiac fibrosis.

The apoptotic effect of GSK-3 inhibitors: BIO and CHIR 98014 on H1975 lung cancer cells through ROS generation and mitochondrial dysfunction.

OBJECTIVE: GSK-3 has been reported to be upregulated in malignant diseases, including lung cancers, thus suggesting it to be a valid target for cancer treatment. The study elucidates the possible mechanism involved in the ability of GSK-3 inhibitors: BIO and CHIR 98014 to regulate proteins involved in cell death of H1975 lung cancer cells. RESULTS: BIO and CHIR 98014 successfully induced apoptosis at lower concentrations in H1975 cells but not in H460 lung cancer cells. Moreover, increased ROS generation and depolarization of mitochondrial membrane potential were observed in both treatments. Cleavage of caspase-3 was observed in both BIO and CHIR 98014-treated cells after 72 h with monolayer and tumorsphere cell culture models. CONCLUSIONS: The use of GSK-3 inhibitors shows promising apoptotic abilities in clinical cancer treatments, particularly for lung cancer cells. This study is the first report to describe the significant apoptotic effects of BIO and CHIR 98014 through multiple mechanisms of H1975 NSCLC that are linked to their proliferative and migratory capacities.

GSK-3 Inhibitors: A Double-Edged Sword? - An Update on Tideglusib.

GSK-3 inhibitors are an emerging tool for clinical interventions in human diseases and represent a niche area in combinational therapy. They possess diverse facets in applications of nervous system disorders, Type 2 diabetes, regenerative medicine and cancer. However, conflicting reports suggest the controversial role of GSK-3 inhibitors in cancers. This review aims to highlight the rise of GSK-3 inhibitors as tools for molecular-targeted research and its shift to a promising drug candidate. The review also focuses on key GSK-3 inhibitors and their roles in cancer and regenerative medicine with special emphasis to tideglusib. In addition, the decisive roles of GSK-3 in various molecular pathways will be concisely reviewed. Finally, this review concludes the emergence of GSK-3 inhibitors as a 'double-edged sword' in the treatment against human diseases cautioning researchers about the potential ramifications of off-target pharmacological effects.

Copper oxide nanoparticles induce anticancer activity in A549 lung cancer cells by inhibition of histone deacetylase.

OBJECTIVES: Copper oxide nanoparticles (CuO NPs) promoting anticancer activity may be due to the regulation of various classes of histone deacetylases (HDACs). RESULTS: Green-synthesized CuO NPs significantly arrested total HDAC level and also suppressed class I, II and IV HDACs mRNA expression in A549 cells. A549 cells treated with CuO NPs downregulated oncogenes and upregulated tumor suppressor protein expression. CuO NPs positively regulated both mitochondrial and death receptor-mediated apoptosis caspase cascade pathway in A549 cells. CONCLUSION: Green-synthesized CuO NPs inhibited HDAC and therefore shown apoptosis mediated anticancer activity in A549 lung cancer cell line.

Correlative Studies Unravelling the Possible Mechanism of Cell Death in Tideglusib-Treated Human Ovarian Teratocarcinoma-Derived PA-1 Cells.

This study aims to unravel the use of GSK-3 inhibitors as viable apoptotic inducers for teratocarcinoma-derived ovarian PA-1 cells. MTT assay was carried out to assess inhibitory concentrations of LiCl and TDG. AO/EB staining and Hoechst 33258 staining were employed to assess the damage. Mitochondrial membrane potential (ΔΨm) and ROS generation were assessed with IC50 concentrations of LiCl and TDG. Tumor-related genes (p53, p21, IL-8, TNF-α, MMP-2, Fas-L, Cox-2, and caspase-3) were assessed with 1/4 IC50, 1/2 IC50, IC50 concentrations by semi-quantitative RT- PCR. Cell cycle analysis was performed with IC50 concentration of LiCl and TDG. Western blot analysis was performed for caspase-3, caspase-7, caspase-9, PARP to estimate the possible damage induced by GSK-3 inhibitors and regulation of GSK-3ß, pGSK-3ß, Cox-2. GSK-3 inhibitors demonstrated a concentration and time-dependent reduction in cell viability, exhibiting significant ROS generation and reduced ΔΨm at their IC50 values. Substantial concentration-dependent gene expression changes with significant upregulation of P21, Cox-2, TNF-α, caspase-3, Fas-L were observed. Protein expression of caspase-3 caspase-7, caspase-9, PARP exhibited significant cleavage in LiCl and TDG-treated cells. Protein expression of Cox-2 was significantly increased in IC50 concentration of TDG. Cell cycle analysis showed significant accumulation of cells at sub-G0-G1.

Tideglusib induces apoptosis in human neuroblastoma IMR32 cells, provoking sub-G0/G1 accumulation and ROS generation.

Neuroblastoma is the most common tumor amongst children amounting to nearly 15% of cancer deaths. This cancer is peculiar in its characteristics, exhibiting differentiation, maturation and metastatic transformation leading to poor prognosis and low survival rates among children. Chemotherapy, though toxic to normal cells, has shown to improve the survival of the patient with emphasis given more towards targeting angiogenesis. Recently, Tideglusib was designed as an 'Orphan Drug' to target the neurodegenerative Alzheimer's disease and gained significant momentum in its function during clinical trials. Duffy et al. recently reported a reduction in cell viability of human IMR32 neuroblastoma cells when treated with Tideglusib at varying concentrations. We investigated the effects of Tideglusib, at various concentrations, compared to Lithium chloride at various concentrations, on IMR32 cells. Lithium, a known GSK-3 inhibitor, was used as a standard to compare the efficiency of Tideglusib in a dose-dependent manner. Cell viability was assessed by MTT assay. The stages of apoptosis were evaluated by AO/EB staining and nuclear damage was determined by Hoechst 33258 staining. Reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) were assessed by DCFDA dye and Rhodamine-123 dye, respectively. Tideglusib reported a significant dose-dependent increase in pro-apoptotic proteins (PARP, Caspase-9, Caspase-7, Caspase-3) and tumor-related genes (FasL, TNF-α, Cox-2, IL-8, Caspase-3). Anti-GSK3 ß, pGSK3 ß, Bcl-2, Akt-1, p-Akt1 protein levels were observed with cells exposed to Tideglusib and Lithium chloride. No significant dose-dependent changes were observed for the mRNA expression of collagenase MMP-2, the tumor suppressor p53, or the cell cycle protein p21. Our study also reports Tideglusib reducing colony formation and increasing the level of sub-G0/G1 population in IMR32 cells. Our investigations report the significance of Tideglusib as a promising apoptotic inducer in human neuroblastoma IMR32 cells. Our study also reports that LiCl reduced cell viability in IMR32 cells inducing apoptosis mediated by ROS generation.