Aberrant expression of glycogen synthase kinase-3β in human breast and head and neck cancer

Identification of a novel GSK3β inhibitor involved in abrogating KRas dependent pancreatic tumors in Wnt/beta-catenin and NF-kB dependent manner

Pancreatic cancer is an aggressive malignancy with a poor survival rate because it is difficult to diagnose the disease during its early stages. The currently available treatments, which include surgery, chemotherapy and radiation therapy, offer only limited survival benefit. Pharmacological interventions to inhibit Glycogen Synthase Kinase-3beta (GSK3β) activity is an important therapeutic strategy for the treatment of pancreatic cancer because GSK3β is one of the key factors involved in the onset, progression as well as in the acquisition of chemoresistance in pancreatic cancer. Here, we report the identification of MJ34 as a potent GSK3β inhibitor that significantly reduced growth and survival of human mutant KRas dependent pancreatic tumors. MJ34 mediated GSK3β inhibition was seen to induce apoptosis in a β-catenin dependent manner and downregulate NF-kB activity in MiaPaCa-2 cells thereby impeding cell survival and anti-apoptotic processes in these cells as well as in the xenograft model of pancreatic cancer. In vivo acute toxicity and in vitro cardiotoxicity studies indicate that MJ34 is well tolerated without any adverse effects. Taken together, we report the discovery of MJ34 as a potential drug candidate for the therapeutic treatment of mutant KRas-dependent human cancers through pharmacological inhibition of GSK3β.

Cytotoxicity of alkaloids isolated from Peganum harmala seeds on HCT116 human colon cancer cells

BACKGROUND

The present study aimed to elucidate the potential anticancer activity and mechanism of P. harmala's alkaloid extract, harmine (HAR), and harmaline (HAL) in HCT-116 colorectal cancer cells.

METHODS AND RESULTS

P. harmala's alkaloid was extracted from harmala seeds. HCT-116 cells were treated with P. harmala's alkaloid extract, HAR and HAL. Cytotoxicity was determined by MTT assay, apoptotic activity detected via flow cytometry and acridine orange (AO)/ethidium bromide (EB) dual staining, and cell cycle distribution analyzed with flow cytometry. The mRNA expression of Bcl-2-associated X protein (Bax) and glycogen synthase kinase-3 beta (GSK3β) was measured by real-time PCR. Furthermore, the expression of Bax, Bcl-2, GSK3β and p53 proteins, were determined by western blotting. The findings indicated that, P. harmala's alkaloids extract, HAR and HAL were significantly cytotoxic toward HCT116 cells after 24 and 48 h of treatment. We showed that P. harmala's alkaloid extract induce apoptosis and cell cycle arrest at G2 phase in the HCT116 cell line. Downregulation of GSK3β and Bcl-2 and upregulation of Bax and p53 were observed.

CONCLUSION

The findings of this study indicate that the P. harmala's alkaloid extract has anticancer activity and may be further investigated to develop future anticancer chemotherapeutic agents.

Glycogen Synthase Kinase 3β: A True Foe in Pancreatic Cancer

Glycogen synthase kinase 3 beta (GSK-3β) is a serine/threonine protein kinase involved in multiple normal and pathological cell functions, including cell signalling and metabolism. GSK-3β is highly expressed in the onset and progression of multiple cancers with strong involvement in the regulation of proliferation, apoptosis, and chemoresistance. Multiple studies showed pro- and anti-cancer roles of GSK-3β creating confusion about the benefit of targeting GSK-3β for treating cancer. In this mini-review, we focus on the role of GSK-3β in pancreatic cancer. We demonstrate that the proposed anti-cancer roles of GSK-3β are not relevant to pancreatic cancer, and we argue why GSK-3β is, indeed, a very promising therapeutic target in pancreatic cancer.

GSK-3β in Pancreatic Cancer: Spotlight on 9-ING-41, Its Therapeutic Potential and Immune Modulatory Properties

Simple Summary

Glycogen synthase kinase-3 beta is a protein kinase implicated in the promotion and development of various cancers, including pancreatic cancer. In cell culture and animal studies, drugs targeting the inhibition of this protein show treatment potential in pancreatic cancer. Studies show targeting this protein for treatment may overcome resistance to conventional chemotherapy in pancreatic tumors. Early-stage clinical trials are currently studying small molecule inhibitors targeting glycogen synthase kinase-3 beta and interim results show favorable results. Recent studies also suggest that targeting this protein will create synergy with immunotherapy, such as checkpoint inhibitors. Future studies should aim to study new combination treatments involving glycogen synthase kinase-3 beta targeting drugs with chemotherapy and immunotherapy in pancreatic cancer.

Abstract

Glycogen synthase kinase-3 beta is a ubiquitously and constitutively expressed molecule with pleiotropic function. It acts as a protooncogene in the development of several solid tumors including pancreatic cancer through its involvement in various cellular processes including cell proliferation, survival, invasion and metastasis, as well as autophagy. Furthermore, the level of aberrant glycogen synthase kinase-3 beta expression in the nucleus is inversely correlated with tumor differentiation and survival in both in vitro and in vivo models of pancreatic cancer. Small molecule inhibitors of glycogen synthase kinase-3 beta have demonstrated therapeutic potential in pre-clinical models and are currently being evaluated in early phase clinical trials involving pancreatic cancer patients with interim results showing favorable results. Moreover, recent studies support a rationale for the combination of glycogen synthase kinase-3 beta inhibitors with chemotherapy and immunotherapy, warranting the evaluation of novel combination regimens in the future.

Alterations and molecular targeting of the GSK-3 regulator, PI3K, in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is a highly morbid, genetically unstable disease derived from the mucoepithelium of the upper aerodigestive tract. Recent characterization of this disease has implicated the PI3K-Akt-mTOR pathway as one of the most frequently dysregulated pathways. As such, there are several classes of PI3K inhibitors currently undergoing clinical trials. In this article, we review the PI3K pathway, mutations of this pathway in HNSCC, drugs that target PI3K, the impact of these agents on the PI3K and GSK-3 signaling axes, ongoing clinical trials evaluating PI3K inhibitors, and the challenges of using these drugs in the clinic. This article is part of a Special Issue entitled: GSK-3 and related kinases in cancer, neurological and other disorders edited by James McCubrey, Agnieszka Gizak and Dariusz Rakus.

Candidate Genes and MiRNAs Linked to the Inverse Relationship Between Cancer and Alzheimer's Disease: Insights From Data Mining and Enrichment Analysis

The incidence of cancer and Alzheimer’s disease (AD) increases exponentially with age. A growing body of epidemiological evidence and molecular investigations inspired the hypothesis of an inverse relationship between these two pathologies. It has been proposed that the two diseases might utilize the same proteins and pathways that are, however, modulated differently and sometimes in opposite directions. Investigation of the common processes underlying these diseases may enhance the understanding of their pathogenesis and may also guide novel therapeutic strategies. Starting from a text-mining approach, our in silico study integrated the dispersed biological evidence by combining data mining, gene set enrichment, and protein-protein interaction (PPI) analyses while searching for common biological hallmarks linked to AD and cancer. We retrieved 138 genes (ALZCAN gene set), computed a significant number of enriched gene ontology clusters, and identified four PPI modules. The investigation confirmed the relevance of autophagy, ubiquitin proteasome system, and cell death as common biological hallmarks shared by cancer and AD. Then, from a closer investigation of the PPI modules and of the miRNAs enrichment data, several genes (SQSTM1, UCHL1, STUB1, BECN1, CDKN2A, TP53, EGFR, GSK3B, and HSPA9) and miRNAs (miR-146a-5p, MiR-34a-5p, miR-21-5p, miR-9-5p, and miR-16-5p) emerged as promising candidates. The integrative approach uncovered novel miRNA-gene networks (e.g., miR-146 and miR-34 regulating p62 and Beclin1 in autophagy) that might give new insights into the complex regulatory mechanisms of gene expression in AD and cancer.

Glycogen Synthase Kinase-3 Inhibition Sensitizes Pancreatic Cancer Cells to Chemotherapy by Abrogating the TopBP1/ATR-Mediated DNA Damage Response

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a predominantly fatal common malignancy with inadequate treatment options. Glycogen synthase kinase 3β (GSK-3β) is an emerging target in human malignancies including PDAC.Experimental Design: Pancreatic cancer cell lines and patient-derived xenografts were treated with a novel GSK-3 inhibitor 9-ING-41 alone or in combination with chemotherapy. Activation of the DNA damage response pathway and S-phase arrest induced by gemcitabine were assessed in pancreatic tumor cells with pharmacologic inhibition or siRNA depletion of GSK-3 kinases by immunoblotting, flow cytometry, and immunofluorescence.

RESULTS

9-ING-41 treatment significantly increased pancreatic tumor cell killing when combined with chemotherapy. Inhibition of GSK-3 by 9-ING-41 prevented gemcitabine-induced S-phase arrest suggesting an impact on the ATR-mediated DNA damage response. Both 9-ING-41 and siRNA depletion of GSK-3 kinases impaired the activation of ATR leading to the phosphorylation and activation of Chk1. Mechanistically, depletion or knockdown of GSK-3 kinases resulted in the degradation of the ATR-interacting protein TopBP1, thus limiting the activation of ATR in response to single-strand DNA damage.

CONCLUSIONS

These data identify a previously unknown role for GSK-3 kinases in the regulation of the TopBP1/ATR/Chk1 DNA damage response pathway. The data also support the inclusion of patients with PDAC in clinical studies of 9-ING-41 alone and in combination with gemcitabine.