GSK-3β Governs Inflammation-Induced NFATc2 Signaling Hubs to Promote Pancreatic Cancer Progression

An NFATc1/SMAD3/cJUN Complex Restricted to SMAD4-Deficient Pancreatic Cancer Guides Rational Therapies

BACKGROUND & AIMS

The highly heterogeneous cellular and molecular makeup of pancreatic ductal adenocarcinoma (PDAC) not only fosters exceptionally aggressive tumor biology, but contradicts the current concept of one-size-fits-all therapeutic strategies to combat PDAC. Therefore, we aimed to exploit the tumor biological implication and therapeutic vulnerabilities of a clinically relevant molecular PDAC subgroup characterized by SMAD4 deficiency and high expression of the nuclear factor of activated T cells (SMAD4-/-/NFATc1High).

METHODS

Transcriptomic and clinical data were analyzed to determine the prognostic relevance of SMAD4-/-/NFATc1High cancers. In vitro and in vivo oncogenic transcription factor complex formation was studied by immunoprecipitation, proximity ligation assays, and validated cross model and species. The impact of SMAD4 status on therapeutically targeting canonical KRAS signaling was mechanistically deciphered and corroborated by genome-wide gene expression analysis and genetic perturbation experiments, respectively. Validation of a novel tailored therapeutic option was conducted in patient-derived organoids and cells and transgenic as well as orthotopic PDAC models.

RESULTS

Our findings determined the tumor biology of an aggressive and chemotherapy-resistant SMAD4-/-/NFATc1High subgroup. Mechanistically, we identify SMAD4 deficiency as a molecular prerequisite for the formation of an oncogenic NFATc1/SMAD3/cJUN transcription factor complex, which drives the expression of RRM1/2. RRM1/2 replenishes nucleoside pools that directly compete with metabolized gemcitabine for DNA strand incorporation. Disassembly of the NFATc1/SMAD3/cJUN complex by mitogen-activated protein kinase signaling inhibition normalizes RRM1/2 expression and synergizes with gemcitabine treatment in vivo to reduce the proliferative index.

CONCLUSIONS

Our results suggest that PDAC characterized by SMAD4 deficiency and oncogenic NFATc1/SMAD3/cJUN complex formation exposes sensitivity to a mitogen-activated protein kinase signaling inhibition and gemcitabine combination therapy.

Glycogen synthase kinase 3β: the nexus of chemoresistance, invasive capacity, and cancer stemness in pancreatic cancer

The treatment of pancreatic cancer remains a significant clinical challenge due to the limited number of patients eligible for curative (R0) surgery, failures in the clinical development of targeted and immune therapies, and the pervasive acquisition of chemotherapeutic resistance. Refractory pancreatic cancer is typified by high invasiveness and resistance to therapy, with both attributes related to tumor cell stemness. These malignant characteristics mutually enhance each other, leading to rapid cancer progression. Over the past two decades, numerous studies have produced evidence of the pivotal role of glycogen synthase kinase (GSK)3β in the progression of over 25 different cancer types, including pancreatic cancer. In this review, we synthesize the current knowledge on the pathological roles of aberrant GSK3β in supporting tumor cell proliferation and invasion, as well as its contribution to gemcitabine resistance in pancreatic cancer. Importantly, we discuss the central role of GSK3β as a molecular hub that mechanistically connects chemoresistance, tumor cell invasion, and stemness in pancreatic cancer. We also discuss the involvement of GSK3β in the formation of desmoplastic tumor stroma and in promoting anti-cancer immune evasion, both of which constitute major obstacles to successful cancer treatment. Overall, GSK3β has characteristics of a promising therapeutic target to overcome chemoresistance in pancreatic cancer.

Mind the (guidance) signals! Translational relevance of semaphorins, plexins, and neuropilins in pancreatic cancer

Pancreatic cancer is a major cause of demise worldwide. Although key associated genetic changes have been discovered, disease progression is sustained by pathogenic mechanisms that are poorly understood at the molecular level. In particular, the tissue microenvironment of pancreatic adenocarcinoma (PDAC) is usually characterized by high stromal content, scarce recruitment of immune cells, and the presence of neuronal fibers. Semaphorins and their receptors, plexins and neuropilins, comprise a wide family of regulatory signals that control neurons, endothelial and immune cells, embryo development, and normal tissue homeostasis, as well as the microenvironment of human tumors. We focus on the role of these molecular signals in pancreatic cancer progression, as revealed by experimental research and clinical studies, including novel approaches for cancer treatment.

Mechanisms of obesity- and diabetes mellitus-related pancreatic carcinogenesis: a comprehensive and systematic review

Research on obesity- and diabetes mellitus (DM)-related carcinogenesis has expanded exponentially since these two diseases were recognized as important risk factors for cancers. The growing interest in this area is prominently actuated by the increasing obesity and DM prevalence, which is partially responsible for the slight but constant increase in pancreatic cancer (PC) occurrence. PC is a highly lethal malignancy characterized by its insidious symptoms, delayed diagnosis, and devastating prognosis. The intricate process of obesity and DM promoting pancreatic carcinogenesis involves their local impact on the pancreas and concurrent whole-body systemic changes that are suitable for cancer initiation. The main mechanisms involved in this process include the excessive accumulation of various nutrients and metabolites promoting carcinogenesis directly while also aggravating mutagenic and carcinogenic metabolic disorders by affecting multiple pathways. Detrimental alterations in gastrointestinal and sex hormone levels and microbiome dysfunction further compromise immunometabolic regulation and contribute to the establishment of an immunosuppressive tumor microenvironment (TME) for carcinogenesis, which can be exacerbated by several crucial pathophysiological processes and TME components, such as autophagy, endoplasmic reticulum stress, oxidative stress, epithelial-mesenchymal transition, and exosome secretion. This review provides a comprehensive and critical analysis of the immunometabolic mechanisms of obesity- and DM-related pancreatic carcinogenesis and dissects how metabolic disorders impair anticancer immunity and influence pathophysiological processes to favor cancer initiation.

GSK-3β phosphorylation of DHX33 leads to its ubiquitination mediated protein degradation

DHX33 is a member of DEAD/H box protein family, and is involved in both RNA and DNA metabolism. It plays diverse roles in multiple cellular activities. DHX33 overexpression has been found to promote the development of many human cancers. However, the underlying mechanism to explain its high expression in cancer cells remains incompletely resolved. In this study, with both human cancer cell lines and normal fibroblasts, we found glycogen synthase kinase 3β (GSK-3β) regulates DHX33 protein stability. This is through its direct phosphorylation of DHX33 on T482, which triggers ubiquitination mediate protein degradation. We further identified one of the major ubiquitination sites of DHX33 to be on its N-terminal K94, a critical residue previously found to be important and highly conserved for ATP binding and helicase activity. Our study for the first time reveals an important upstream regulator, GSK-3β, as a critical kinase to phosphorylate DHX33 at the post-translational level leading to its degradation. Moreover, cancer cells have frequent GSK3β deactivation to disrupt this signaling cascade. Therefore, DHX33 is stabilized in many cancer cells as compared to normal cells. Our study unveils an important post-translational regulation of DHX33 in cells and further unveils a novel mechanism for DHX33 overexpression in cancer cells.

Nuclear GSK-3β and Oncogenic KRas Lead to the Retention of Pancreatic Ductal Progenitor Cells Phenotypically Similar to Those Seen in IPMN

Glycogen synthase kinase-3β (GSK-3β) is a downstream target of oncogenic KRas and can accumulate in the nucleus in pancreatic ductal adenocarcinoma (PDA). To determine the interplay between oncogenic KRas and nuclear GSK-3β in PDA development, we generated Lox-STOP-Lox (LSL) nuclear-targeted GSK-3β animals and crossed them with LSL-KRas^G12D mice under the control of the Pdx1-cre transgene—referred to as KNGC. Interestingly, 4-week-old KNGC animals show a profound loss of acinar cells, the expansion of ductal cells, and the rapid development of cystic-like lesions reminiscent of intraductal papillary mucinous neoplasm (IPMN). RNA-sequencing identified the expression of several ductal cell lineage genes including AQP5. Significantly, the Aqp5⁺ ductal cell pool was proliferative, phenotypically distinct from quiescent pancreatic ductal cells, and deletion of AQP5 limited expansion of the ductal pool. Aqp5 is also highly expressed in human IPMN along with GSK-3β highlighting the putative role of Aqp5⁺ ductal cells in human preneoplastic lesion development. Altogether, these data identify nGSK-3β and KRas^G12D as an important signaling node promoting the retention of pancreatic ductal progenitor cells, which could be used to further characterize pancreatic ductal development as well as lineage biomarkers related to IPMN and PDA.

The GSK3 kinase and LZTR1 protein regulate the stability of Ras family proteins and the proliferation of pancreatic cancer cells

Ras family proteins are membrane-bound GTPases that control proliferation, survival, and motility. Many forms of cancers are driven by the acquisition of somatic mutations in a RAS gene. In pancreatic cancer (PC), more than 90% of tumors carry an activating mutation in KRAS. Mutations in components of the Ras signaling pathway can also be the cause of RASopathies, a group of developmental disorders. In a subset of RASopathies, the causal mutations are in the LZTR1 protein, a substrate adaptor for E3 ubiquitin ligases that promote the degradation of Ras proteins. Here, we show that the function of LZTR1 is regulated by the glycogen synthase kinase 3 (GSK3). In PC cells, inhibiting or silencing GSK3 led to a decline in the level of Ras proteins, including both wild type Ras proteins and the oncogenic Kras protein. This decline was accompanied by a 3-fold decrease in the half-life of Ras proteins and was blocked by the inhibition of the proteasome or the knockdown of LZTR1. Irrespective of the mutational status of KRAS, the decline in Ras proteins was observed and accompanied by a loss of cell proliferation. This loss of proliferation was blocked by the knockdown of LZTR1 and could be recapitulated by the silencing of either KRAS or GSK3. These results reveal a novel GSK3-regulated LZTR1-dependent mechanism that controls the stability of Ras proteins and proliferation of PC cells. The significance of this novel pathway to Ras signaling and its contribution to the therapeutic properties of GSK3 inhibitors are both discussed.

A Novel Prognostic Four-Gene Signature of Breast Cancer Identified by Integrated Bioinformatics Analysis

Molecular analysis facilitates the prediction of overall survival (OS) of breast cancer and decision-making of the treatment plan. The current study was designed to identify new prognostic genes for breast cancer and construct an effective prognostic signature with integrated bioinformatics analysis. Differentially expressed genes in breast cancer samples from The Cancer Genome Atlas (TCGA) dataset were filtered by univariate Cox regression analysis. The prognostic model was optimized by the Akaike information criterion and further validated using the TCGA dataset (n = 1014) and Gene Expression Omnibus (GEO) dataset (n = 307). The correlation between the risk score and clinical information was assessed by univariate and multivariate Cox regression analyses. Functional pathways in relation to high-risk and low-risk groups were analyzed using gene set enrichment analysis (GSEA). Four prognostic genes (EXOC6, GPC6, PCK2, and NFATC2) were screened and used to construct a prognostic model, which showed robust performance in classifying the high-risk and low-risk groups. The risk score was significantly related to clinical features and OS. We identified 19 functional pathways significantly associated with the risk score. This study constructed a new prognostic model with a high prediction performance for breast cancer. The four-gene prognostic signature could serve as an effective tool to predict prognosis and assist the management of breast cancer patients.

Inhibition of Noncanonical Ca2+ Oscillation/Calcineurin/GSK-3β Pathway Contributes to Anti-Inflammatory Effect of Sigma-1 Receptor Activation

Further understanding the mechanism for microglia activation is necessary for developing novel anti-inflammatory strategies. Our previous study found that the activation of sigma-1 receptor can effectively inhibit the neuroinflammation, independent of the canonical mechanisms, such as NF-κB, JNK and ERK inflammatory pathways. Thus, it is reasonable that an un-identified, non-canonical pathway contributes to the activation of microglia. In the present study, we found that a sigma-1 receptor agonist of 2-morpholin-4-ylethyl 1-phenylcyclohexane-1-carboxylate (PRE-084) suppressed lipopolysaccharide (LPS) elevated nitric oxide (NO) content in BV-2 microglia culture supernatant and LPS-raised mRNA levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) in BV-2 microglia. Moreover, PRE-084 alleviated LPS-increased Ser 9 de-phosphorylation of glycogen synthase kinase-3 beta (GSK-3β), LPS-elevated catalytic activity of calcineurin, and LPS-raised percent and frequency of Ca2+ oscillatory BV-2 cells. We further found that the inhibitory effect of PRE-084 was reversed by a calcineurin activator of chlorogenic acid and a GSK-3β activator of pyrvinium. Moreover, an IP3 receptor inhibitor of 2-aminoethoxydiphenyl borate mimicked the anti-inflammatory activity of PRE-084. Thus, we identified a noncanonical pro-neuroinflammary pathway of Ca2+ oscillation/Calcineurin/GSK-3β and the inhibition of this pathway is necessary for the anti-inflammatory activity of sigma-1 receptor activation.

The Role of Dietary Fats in the Development and Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a significant cause of mortality and morbidity in preterm infants. The pathogenesis of NEC is not completely understood; however, intestinal immaturity and excessive immunoreactivity of intestinal mucosa to intraluminal microbes and nutrients appear to have critical roles. Dietary fats are not only the main source of energy for preterm infants, but also exert potent effects on intestinal development, intestinal microbial colonization, immune function, and inflammatory response. Preterm infants have a relatively low capacity to digest and absorb triglyceride fat. Fat may thereby accumulate in the ileum and contribute to the development of NEC by inducing oxidative stress and inflammation. Some fat components, such as long-chain polyunsaturated fatty acids (LC-PUFAs), also exert immunomodulatory roles during the early postnatal period when the immune system is rapidly developing. LC-PUFAs may have the ability to modulate the inflammatory process of NEC, particularly when the balance between n3 and n6 LC-PUFAs derivatives is maintained. Supplementation with n3 LC-PUFAs alone may have limited effect on NEC prevention. In this review, we describe how various fatty acids play different roles in the pathogenesis of NEC in preterm infants.

Chromatin-Independent Interplay of NFATc1 and EZH2 in Pancreatic Cancer

Background: The Nuclear Factor of Activated T-cells 1 (NFATc1) transcription factor and the methyltransferase Enhancer of Zeste Homolog 2 (EZH2) significantly contribute to the aggressive phenotype of pancreatic ductal adenocarcinoma (PDAC). Herein, we aimed at dissecting the mechanistic background of their interplay in PDAC progression. Methods: NFATc1 and EZH2 mRNA and protein expression and complex formation were determined in transgenic PDAC models and human PDAC specimens. NFATc1 binding on the Ezh2 gene and the consequences of perturbed NFATc1 expression on Ezh2 transcription were explored by Chromatin Immunoprecipitation (ChIP) and upon transgenic or siRNA-mediated interference with NFATc1 expression, respectively. Integrative analyses of RNA- and ChIP-seq data was performed to explore NFATc1-/EZH2-dependent gene signatures. Results: NFATc1 targets the Ezh2 gene for transcriptional activation and biochemically interacts with the methyltransferase in murine and human PDAC. Surprisingly, our genome-wide binding and expression analyses do not link the protein complex to joint gene regulation. In contrast, our findings provide evidence for chromatin-independent functions of the NFATc1:EZH2 complex and reveal posttranslational EZH2 phosphorylation at serine 21 as a prerequisite for robust complex formation. Conclusion: Our findings disclose a previously unknown NFATc1-EZH2 axis operational in the pancreas and provide mechanistic insights into the conditions fostering NFATc1:EZH2 complex formation in PDAC.

GSK3β as a novel promising target to overcome chemoresistance in pancreatic cancer

Pancreatic cancer is an aggressive malignancy with increasing incidence and poor prognosis due to its late diagnosis and intrinsic chemoresistance. Most pancreatic cancer patients present with locally advanced or metastatic disease characterized by inherent resistance to chemotherapy. These features pose a series of therapeutic challenges and new targets are urgently needed. Glycogen synthase kinase 3 beta (GSK3β) is a conserved serine/threonine kinase, which regulates key cellular processes including cell proliferation, DNA repair, cell cycle progression, signaling and metabolic pathways. GSK3β is implicated in non-malignant and malignant diseases including inflammation, neurodegenerative diseases, diabetes and cancer. GSK3β recently emerged among the key factors involved in the onset and progression of pancreatic cancer, as well as in the acquisition of chemoresistance. Intensive research has been conducted on key oncogenic functions of GSK3β and its potential as a druggable target; currently developed GSK3β inhibitors display promising results in preclinical models of distinct tumor types, including pancreatic cancer. Here, we review the latest findings about GSK-3β biology and its role in the development and progression of pancreatic cancer. Moreover, we discuss therapeutic agents targeting GSK3β that could be administered as monotherapy or in combination with other drugs to surmount chemoresistance. Several studies are also defining potential gene signatures to identify patients who might benefit from GSK3β-based therapeutic intervention. This detailed overview emphasizes the urgent need of additional molecular studies on the impact of GSK3β inhibition as well as structural analysis of novel compounds and omics studies of predictive biomarkers.

TRPC3 promotes tumorigenesis of gastric cancer via the CNB2/GSK3β/NFATc2 signaling pathway

The transient receptor potential canonical (TRPC) channels have been implicated in various types of malignancies including gastric cancer (GC). However, the detailed mechanisms of TRPC channels underlying cell proliferation and apoptosis of GC cells remain largely unknown. Here, we report that TRPC3 was highly expressed in clinical GC specimens and correlated with GC malignant progression and poor prognosis. Forced expression of TRPC3 in GC cells enhanced both receptor-operated Ca²⁺ entry (ROCE) and store-operated Ca²⁺ entry (SOCE) and promoted the nuclear factor of activated T cell 2 (NFATc2) nuclear translocation by AKT/GSK-3β and CNB2 signaling. Pharmacological inhibition of TRPC3 or CRISPR/Cas9-mediated TRPC3 knockout effectively inhibited the growth of GC cells both in vitro and in vivo. These effects were reversible by the rescue of TRPC3 expression. Furthermore, we confirmed the role of TRPC3 and the ROCE-AKT/GSK3β-CNB2/NFATc2 signaling cascade in regulating cell cycle checkpoint, apoptosis cascade, and intracellular ROS production in GC. Overall, our findings suggest an oncogenic role of TRPC3 in GC and may highlight a potential target of TRPC3 for therapeutic intervention of GC and its malignant progression.

Src-1 and SP2 promote the proliferation and epithelial-mesenchymal transition of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is characterized by high morbidity and morality, especially in Southern China. Transcription factors intensively participate in the initiation and development of NPC. This study aimed to investigate the roles of Src-1 in NPC. mRNA level was determined by qRT-PCR. Western blot was carried out for the protein level. CCK-8 assay was performed to determine cell viability, colony formation for NPC cell proliferation, and transwell for cell migration and invasion ability. The results showed Steroid receptor coactivator 1 (Src-1) was overexpressed in SNE-2 and 6-10B. The expression of Src-1 and SP2 was in positive correlation. Overexpression of Src-1 promoted the cell viability, colony formation, and epithelial-mesenchymal transition (EMT), manifested by the increase of migration and invasion ability, while knockdown of Src-1 exerted opposite effects. Additionally, knockdown or overexpression of SP2 reversed the effects of overexpressed or downregulated Src-1, which was reversed by the depletion of SP2. Moreover, Src-1 interacted with SP2 to regulate EMT-related genes such as E-cad, N-cad, Vimentin, and ZEB1, and proliferation- and apoptosis-related genes, such as bax, cytochrome c, and cleaved caspase3 and bcl-2. Thus, blocking the interaction between Src-1 and SP2 may be a therapeutic target for inhibiting the metastasis of NPC.

The molecular biology of pancreatic adenocarcinoma: translational challenges and clinical perspectives

Pancreatic cancer is an increasingly common cause of cancer mortality with a tight correspondence between disease mortality and incidence. Furthermore, it is usually diagnosed at an advanced stage with a very dismal prognosis. Due to the high heterogeneity, metabolic reprogramming, and dense stromal environment associated with pancreatic cancer, patients benefit little from current conventional therapy. Recent insight into the biology and genetics of pancreatic cancer has supported its molecular classification, thus expanding clinical therapeutic options. In this review, we summarize how the biological features of pancreatic cancer and its metabolic reprogramming as well as the tumor microenvironment regulate its development and progression. We further discuss potential biomarkers for pancreatic cancer diagnosis, prediction, and surveillance based on novel liquid biopsies. We also outline recent advances in defining pancreatic cancer subtypes and subtype-specific therapeutic responses and current preclinical therapeutic models. Finally, we discuss prospects and challenges in the clinical development of pancreatic cancer therapeutics.

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.

Propofol maintains Th17/Treg cell balance and reduces inflammation in rats with traumatic brain injury via the miR‑145‑3p/NFATc2/NF‑κB axis

Propofol is a commonly used intravenous anesthetic. The aim of the study was to examine the mechanism of propofol in traumatic brain injury (TBI) by regulating interleukin (IL)‑17 activity and maintaining the Th17/Treg balance. A rat model with moderate TBI was established using the weight‑drop method. Rats with TBI were regularly injected with propofol and their brain injuries were monitored. The peripheral blood of rats was collected to measure the Th17/Treg ratio. MicroRNA (miR)‑145‑3p expression was detected in the brain tissues of rats and antagomiR‑145‑3p was injected into the lateral ventricles of their brains to verify the effect of miR‑145‑3p on brain injury. The downstream target of miR‑145‑3p was predicted. The targeting relationship between miR‑145‑3p and nuclear factor of activated T cells c2 (NFATc2) was confirmed. NFATC2 expression and phosphorylation of NF‑κB pathway‑related proteins were measured. Propofol alleviated brain injury in rats with TBI and maintained the Th17/Treg balance. Propofol upregulated miR‑145‑3p expression in rat brains, while the inhibition of miR‑145‑3p reversed the effect of propofol on brain injury. A binding relationship was observed between miR‑145‑3p and NFATc2. Furthermore, propofol decreased the phosphorylation of p65 and IκBα, and inhibited activation of the NF‑κB pathway in the brains of rats with TBI. In conclusion, propofol maintained Th17/Treg balance and reduced inflammation in the rats with TBI via the miR‑145‑3p/NFATc2/NF‑κB axis.

GSK-3β Can Regulate the Sensitivity of MIA-PaCa-2 Pancreatic and MCF-7 Breast Cancer Cells to Chemotherapeutic Drugs, Targeted Therapeutics and Nutraceuticals

Glycogen synthase kinase-3 (GSK-3) is a regulator of signaling pathways. KRas is frequently mutated in pancreatic cancers. The growth of certain pancreatic cancers is KRas-dependent and can be suppressed by GSK-3 inhibitors, documenting a link between KRas and GSK-3. To further elucidate the roles of GSK-3β in drug-resistance, we transfected KRas-dependent MIA-PaCa-2 pancreatic cells with wild-type (WT) and kinase-dead (KD) forms of GSK-3β. Transfection of MIA-PaCa-2 cells with WT-GSK-3β increased their resistance to various chemotherapeutic drugs and certain small molecule inhibitors. Transfection of cells with KD-GSK-3β often increased therapeutic sensitivity. An exception was observed with cells transfected with WT-GSK-3β and sensitivity to the BCL2/BCLXL ABT737 inhibitor. WT-GSK-3β reduced glycolytic capacity of the cells but did not affect the basal glycolysis and mitochondrial respiration. KD-GSK-3β decreased both basal glycolysis and glycolytic capacity and reduced mitochondrial respiration in MIA-PaCa-2 cells. As a comparison, the effects of GSK-3 on MCF-7 breast cancer cells, which have mutant PIK3CA, were examined. KD-GSK-3β increased the resistance of MCF-7 cells to chemotherapeutic drugs and certain signal transduction inhibitors. Thus, altering the levels of GSK-3β can have dramatic effects on sensitivity to drugs and signal transduction inhibitors which may be influenced by the background of the tumor.

Downregulation of GSK-3β Expression via Ultrasound-Targeted Microbubble Destruction Enhances Atherosclerotic Plaque Stability in New Zealand Rabbits

Accumulating evidence suggests that atherosclerosis (AS) is the underlying cause of vascular diseases, including heart disease and stroke. Ultrasound-targeted microbubble destruction (UTMD) technology provides a tolerable, efficient and effective system for drug delivery and gene transfection, which has broad application prospects in the treatment of AS. In addition, glycogen synthase kinase (GSK)-3β has been implicated as a potentially valuable therapeutic agent for AS treatment; however, the specific molecular mechanisms remain unknown. Therefore, this study was conducted to explore the effect of downregulation of GSK-3β expression via UTMD on atherosclerotic plaque stability. We established a THP-1 macrophage-derived foam cell model in vitro and an atherosclerotic plaque model in the right common carotid artery of New Zealand rabbits. We determined levels of the relevant vulnerable plaque stability elements. The results indicate that GSK-3β was upregulated in the foam cells and in atherosclerotic rabbits. Downregulation of GSK-3β expression by UTMD suppressed vulnerable plaque factors and inflammation in vitro and in vivo, changed the cytoskeleton of the foam cells in vitro, increased Young's modulus and decreased the peak intensity of atherosclerotic plaque in vivo. Moreover, GSK-3β inhibition by UTMD did not influence the viability of the foam cells. Collectively, our results indicate that GSK-3β could be a potential target for anti-atherogenic interventions and, in particular, can improve the stability of AS plaques in combination with UTMD.

Beneficial role of oleuropein in sepsis-induced myocardial injury. Possible Involvement of GSK-3β/NF-kB pathway

Purpose

The present study explored the potential therapeutic role of oleuropein in sepsis-induced heart injury along with the role of GSK-3β/NF-kB signaling pathway.

Methods

Sepsis-induced myocardial injury was induced by cecal ligation and puncture (CLP) in rats. The cardiac injury was assessed by measuring the levels of cTnI and creatine kinase-MB (CK-MB). Sepsis-induced inflammation was assessed by measuring interleukin-6 (IL-6), IL-10 and HMGB1 levels. The different doses of oleuropein (5, 10, and 20 mg/kg) were given prior to CLP. Oleuropein (20 mg/kg) was administered after 6 hof CLP. The expressions of GSK-3β, p-GSK-3β (Ser9) and nuclear factor-κB (NF-κB) were measured in heart homogenates.

Results

Cecal ligation and puncture was associated with myocardial injury, an increase in IL-6, a decrease in IL-10 and an increase in HMGB1. Moreover, it decreased the ratio of p-GSK-3β/GSK-3β and increased the expression of p-NF-kB. Pretreatment with oleuropein attenuated CLP-induced myocardial injury and systemic inflammation in a dose-dependent manner. Administration of oleuropein after the onset of CLP also attenuated cardiac injury and inflammation. It also restored CLP-induced changes in the HMGB1 levels, the ratio of p-GSK-3β/GSK-3β and expression of p- NF-kB.

Conclusions

Oleuropein attenuates sepsis-induced systemic inflammation and myocardial injury by inhibiting NF-kB and GSK-3β signaling.

Lithium and Therapeutic Targeting of GSK-3

Lithium salts have been in the therapeutic toolbox for better or worse since the 19th century, with purported benefit in gout, hangover, insomnia, and early suggestions that lithium improved psychiatric disorders. However, the remarkable effects of lithium reported by John Cade and subsequently by Mogens Schou revolutionized the treatment of bipolar disorder. The known molecular targets of lithium are surprisingly few and include the signaling kinase glycogen synthase kinase-3 (GSK-3), a group of structurally related phosphomonoesterases that includes inositol monophosphatases, and phosphoglucomutase. Here we present a brief history of the therapeutic uses of lithium and then focus on GSK-3 as a therapeutic target in diverse diseases, including bipolar disorder, cancer, and coronavirus infections.

STIM1 Mediates Calcium-Dependent Epigenetic Reprogramming in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) displays a dismal prognosis due to late diagnosis and high chemoresistance incidence. For advanced disease stages or patients with comorbidities, treatment options are limited to gemcitabine alone or in combination with other drugs. While gemcitabine resistance has been widely attributed to the levels of one of its targets, RRM1, the molecular consequences of gemcitabine resistance in PDAC remain largely elusive. Here we sought to identify genomic, epigenomic, and transcriptomic events associated with gemcitabine resistance in PDAC and their potential clinical relevance. We found that gemcitabine-resistant cells displayed a coamplification of the adjacent RRM1 and STIM1 genes. Interestingly, RRM1, but not STIM1, was required for gemcitabine resistance, while high STIM1 levels caused an increase in cytosolic calcium concentration. Higher STIM1-dependent calcium influx led to an impaired endoplasmic reticulum stress response and a heightened nuclear factor of activated T-cell activity. Importantly, these findings were confirmed in patient and patient-derived xenograft samples. Taken together, our study uncovers previously unknown biologically relevant molecular properties of gemcitabine-resistant tumors, revealing an undescribed function of STIM1 as a rheostat directing the effects of calcium signaling and controlling epigenetic cell fate determination. It further reveals the potential benefit of targeting STIM1-controlled calcium signaling and its downstream effectors in PDAC. SIGNIFICANCE: Gemcitabine-resistant and some naïve tumors coamplify RRM1 and STIM1, which elicit gemcitabine resistance and induce a calcium signaling shift, promoting ER stress resistance and activation of NFAT signaling.

GSK-3β Regulates the Expression of P21 to Promote the Progression of Chordoma

Purpose

Chordoma is a rare malignant bone tumor transformed from the remnants of notochord. It is characterized as highly aggressive and locally invasive, difficult to be completely removed by surgery, and has a poor clinical prognosis. Glycogen synthase kinase 3 beta (GSK-3β) is involved in many cellular processes. GSK-3β overexpression has been shown to promote the development of many cancers, according to previous studies. However, the role of GSK-3β in chordoma remains unclear.

Methods

Immunohistochemistry (IHC) and Western blotting (WB) were performed on clinical specimens to measure GSK-3β expression in chordoma, and immunofluorescence and quantitative real-time polymerase chain reaction (QRT-PCR) were performed to examine the expression of GSK-3β and P21 in cell lines. Cell proliferation was detected by the CCK-8 assay and colony formation analysis, cell migration and invasion checked by Transwell experiments, and cell apoptosis was determined by Annexin V/propidium iodide staining. P21 was predicted as a downstream target gene of GSK-3β using STRING and UNIHI databases. Moreover, we used immunoprecipitation to confirm that GSK-3β and P21 interacted with each other. The double luciferase reporter gene assay showed that GSK-3β could regulate the promoter activity of P21. Finally, the role of the GSK-3β -P21 pathway in chordoma tumorigenesis was analyzed in vivo in nude mice.

Results

Our study showed that GSK-3β was significantly higher in chordoma tissues than in paracancer tissues, and siRNA knockdown of GSK-3β inhibited chordoma cell proliferation and promoted cell apoptosis. Additionally, our research found that GSK-3β bound and downregulated the expression of the P21 gene, and the expression of silencing P21 partially reversed the inhibitory effect of knockdown GSK-3β on chordoma. Furthermore, xenografts showed that knockdown GSK-3β inhibited the formation of chordomas in vivo.

Conclusion

Our results indicated that the GSK-3β-P21 axis may be an important signaling pathway for the occurrence and development of chordoma, providing a new therapeutic target for the clinical treatment of this disorder.

NFATC2 Modulates Radiation Sensitivity in Dermal Fibroblasts From Patients With Severe Side Effects of Radiotherapy

Although it is well established that 5 to 15% of radiotherapy patients exhibit severe side-effects in non-cancerous tissues, the molecular mechanisms involved are still poorly known, and the links between cellular and tissue radiosensitivity are still debated. We here studied fibroblasts from non-irradiated skin of patients with severe sequelae of radiotherapy, to determine whether specific basal cell activities might be involved in susceptibility to side-effects in normal tissues. Compared to control cells, patient fibroblasts exhibited higher radiosensitivity together with defects in DNA repair. Transcriptome profiling of dermal fibroblasts from 16 radiotherapy patients with severe side-effects and 8 healthy individuals identified 540 genes specifically deregulated in the patients. Nuclear factor of activated T cells 2 (NFATC2) was the most differentially expressed gene, poorly expressed at both transcript and protein level, whereas the NFATC2 gene region was hypermethylated. Furthermore, NFATC2 expression correlated with cell survival after irradiation. Finally, silencing NFATC2 in normal cells by RNA interference led to increased cellular radiosensitivity and defects in DNA repair. This study demonstrates that patients with clinical hypersensitivity also exhibit intrinsic cellular radiosensitivity in their normal skin cells. It further reveals a new role for NFATC2 as a potential regulator of cellular sensitivity to ionizing radiation.

PGRMC1 Inhibits Progesterone-Evoked Proliferation and Ca2+ Entry Via STIM2 in MDA-MB-231 Cells

Progesterone receptor membrane component 1 (PGRMC1) has been shown to regulate some cancer hallmarks. Progesterone (P₄) evokes intracellular calcium (Ca²⁺) changes in the triple-negative breast cancer cell lines (MDA-MB-231, MDA-MB-468, and BT-20) and in other breast cancer cell lines like the luminal MCF7 cells. PGRMC1 expression is elevated in MDA-MB-231 and MCF7 cells as compared to non-tumoral MCF10A cell line, and PGRMC1 silencing enhances P₄-evoked Ca²⁺ mobilization. Here, we found a new P₄-dependent Ca²⁺ mobilization pathway in MDA-MB-231 cells and other triple-negative breast cancer cells, as well as in MCF7 cells that involved Stromal interaction molecule 2 (STIM2), Calcium release-activated calcium channel protein 1 (Orai1), and Transient Receptor Potential Channel 1 (TRPC1). Stromal interaction molecule 1 (STIM1) was not involved in this novel Ca²⁺ pathway, as evidenced by using siRNA STIM1. PGRMC1 silencing reduced the negative effect of P₄ on cell proliferation and cell death in MDA-MB-231 cells. In line with the latter observation, Nuclear Factor of Activated T-Cells 1 (NFAT1) nuclear accumulation due to P₄ incubation for 48 h was enhanced in cells transfected with the small hairpin siRNA against PGRMC1 (shPGRMC1). These results provide evidence for a novel P₄-evoked Ca²⁺ entry pathway that is downregulated by PGRMC1.

CXCR3 and Cognate Ligands are Associated with Immune Cell Alteration and Aggressiveness of Pancreatic Ductal Adenocarcinoma

PURPOSE

The cytokine milieu in pancreatic ductal adenocarcinoma (PDAC) promotes tumor progression and immune suppression, contributing to the dismal prognosis of patients with PDAC. The roles of many of these cytokines, however, have not been thoroughly investigated in PDAC.

EXPERIMENTAL DESIGN

PDAC microarray and The Cancer Genome Atlas datasets were analyzed to identify cytokines and cognate receptors overexpressed in PDAC and associated with survival. Pathway and CIBERSORT analyses were used to elucidate potential mechanisms of altered patient survival. Comparative analysis of cytokine expression in KPC (K-ras^G12D; TP53^R172H; Pdx-1cre) and KC (K-ras^G12D; Pdx-1cre) PDAC models and multicolor immunofluorescence (IF) staining of human PDAC-resected samples were used to validate these findings.

RESULTS

CXCL9 and CXCL10 were among the most highly overexpressed cytokines by bioinformatics analyses, while their receptor, CXCR3, was significantly overexpressed by IHC analysis. Higher CXCR3 ligand expression was associated with shorter overall survival, while high CXCR3 expression was associated with better survival. The CXCR3 ligands, CXCL4, 9, and 10, were overexpressed in KPC compared with KC mice. Pathway analysis of CXCR3- and CXCR3 ligand-associated genes showed that CXCR3 is a marker of antitumor immunity, while its ligands may promote immunosuppression. CIBERSORT and IF studies of PDAC tissues demonstrated that high CXCR3 expression was associated with increased CD8⁺ T-cell and naïve B-cell signatures and loss of plasma cell signatures. CXCR3 ligand expression was associated with increased CD8⁺ T-cell signatures and loss of natural killer-cell signatures.

CONCLUSIONS

CXCR3 ligands are overexpressed in PDAC and are associated with poor survival likely related to alterations in tumor immune infiltrate/activity.

Glycogen Synthase Kinase 3β in Cancer Biology and Treatment

Glycogen synthase kinase (GSK)3β is a multifunctional serine/threonine protein kinase with more than 100 substrates and interacting molecules. GSK3β is normally active in cells and negative regulation of GSK3β activity via phosphorylation of its serine 9 residue is required for most normal cells to maintain homeostasis. Aberrant expression and activity of GSK3β contributes to the pathogenesis and progression of common recalcitrant diseases such as glucose intolerance, neurodegenerative disorders and cancer. Despite recognized roles against several proto-oncoproteins and mediators of the epithelial–mesenchymal transition, deregulated GSK3β also participates in tumor cell survival, evasion of apoptosis, proliferation and invasion, as well as sustaining cancer stemness and inducing therapy resistance. A therapeutic effect from GSK3β inhibition has been demonstrated in 25 different cancer types. Moreover, there is increasing evidence that GSK3β inhibition protects normal cells and tissues from the harmful effects associated with conventional cancer therapies. Here, we review the evidence supporting aberrant GSK3β as a hallmark property of cancer and highlight the beneficial effects of GSK3β inhibition on normal cells and tissues during cancer therapy. The biological rationale for targeting GSK3β in the treatment of cancer is also discussed at length.

Carcinogenesis of Pancreatic Ductal Adenocarcinoma

Although the estimated time for development of pancreatic ductal adenocarcinoma (PDA) is more than 20 years, PDAs are usually detected at late, metastatic stages. PDAs develop from duct-like cells through a multistep carcinogenesis process, from low-grade dysplastic lesions to carcinoma in situ and eventually to metastatic disease. This process involves gradual acquisition of mutations in oncogenes and tumor suppressor genes, as well as changes in the pancreatic environment from a pro-inflammatory microenvironment that favors the development of early lesions, to a desmoplastic tumor microenvironment that is highly fibrotic and immune suppressive. This review discusses our current understanding of how PDA originates.

Glycogen synthase kinase-3β: a novel therapeutic target for pancreatic cancer

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States with a single-digit 5-year survival rate despite advances in understanding the genetics and biology of the disease. Glycogen synthase kinase-3α (GSK-3α) and GSK-3β are serine/threonine kinases that localize to the cytoplasm, mitochondria and nucleus. Although they are highly homologous within their kinase domains and phosphorylate an overlapping set of target proteins, genetic studies have shown that GSK-3β regulates the activity of several proteins that promote neoplastic transformation. Significantly, GSK-3β is progressively overexpressed during PDAC development where it participates in tumor progression, survival and chemoresistance. Thus, GSK-3β has become an attractive target for treating PDAC.Areas covered: This review summarizes the mechanisms regulating GSK-3β activity, including upstream translational and post-translational regulation, as well as the downstream targets and their functions in PDAC cell growth, metastasis and chemoresistance.Expert opinion: The activity of GSK-3 kinases are considered cell- and context-specific. In PDAC, oncogenic KRas drives the transcriptional expression of the GSK-3β gene, which has been shown to regulate cancer cell proliferation and survival, as well as resistance to chemotherapy. Thus, the combination of GSK-3 inhibitors with chemotherapeutic drugs could be a promising strategy for PDAC.

Glycogen synthase kinase-3 beta inhibitors as novel cancer treatments and modulators of antitumor immune responses

As a kinase at the crossroads of numerous metabolic and cell growth signaling pathways, glycogen synthase kinase-3 beta (GSK-3β) is a highly desirable therapeutic target in cancer. Despite its involvement in pathways associated with the pathogenesis of several malignancies, no selective GSK-3β inhibitor has been approved for the treatment of cancer. The regulatory role of GSK-3β in apoptosis, cell cycle, DNA repair, tumor growth, invasion, and metastasis reflects the therapeutic relevance of this target and provides the rationale for drug combinations. Emerging data on GSK-3β as a mediator of anticancer immune response also highlight the potential clinical applications of novel selective GSK-3β inhibitors that are entering clinical studies. This manuscript reviews the preclinical and early clinical results with GSK-3β inhibitors and delineates the developmental therapeutics landscape for this potentially important target in cancer therapy.

An actionable axis linking NFATc2 to EZH2 controls the EMT-like program of melanoma cells

Discovery of new actionable targets and functional networks in melanoma is an urgent need as only a fraction of metastatic patients achieves durable clinical benefit by targeted therapy or immunotherapy approaches. Here we show that NFATc2 expression is associated with an EMT-like transcriptional program and with an invasive melanoma phenotype, as shown by analysis of melanoma cell lines at the mRNA and protein levels, interrogation of the TCGA melanoma dataset and characterization of melanoma lesions by immunohistochemistry. Gene silencing or pharmacological inhibition of NFATc2 downregulated EMT-related genes and AXL, and suppressed c-Myc, FOXM1, and EZH2. Targeting of c-Myc suppressed FOXM1 and EZH2, while targeting of FOXM1 suppressed EZH2. Inhibition of c-Myc, or FOXM1, or EZH2 downregulated EMT-related gene expression, upregulated MITF and suppressed migratory and invasive activity of neoplastic cells. Stable silencing of NFATc2 impaired melanoma cell proliferation in vitro and tumor growth in vivo in SCID mice. In NFATc2⁺ EZH2⁺ melanoma cell lines pharmacological co-targeting of NFATc2 and EZH2 exerted strong anti-proliferative and pro-apoptotic activity, irrespective of BRAF or NRAS mutations and of BRAF inhibitor resistance. These results provide preclinical evidence for a role of NFATc2 in shaping the EMT-like melanoma phenotype and reveal a targetable vulnerability associated with NFATc2 and EZH2 expression in melanoma cells belonging to different mutational subsets.

Experimental Therapy of Advanced Breast Cancer: Targeting NFAT1-MDM2-p53 Pathway

Advanced breast cancer, especially advanced triple-negative breast cancer, is typically more aggressive and more difficult to treat than other breast cancer phenotypes. There is currently no curable option for breast cancer patients with advanced diseases, highlighting the urgent need for novel treatment strategies. We have recently discovered that the nuclear factor of activated T cells 1 (NFAT1) activates the murine double minute 2 (MDM2) oncogene. Both MDM2 and NFAT1 are overexpressed and constitutively activated in breast cancer, particularly in advanced breast cancer, and contribute to its initiation, progression, and metastasis. MDM2 regulates cancer cell proliferation, cell cycle progression, apoptosis, migration, and invasion through both p53-dependent and -independent mechanisms. We have proposed to target the NFAT1-MDM2-p53 pathway for the treatment of human cancers, especially breast cancer. We have recently identified NFAT1 and MDM2 dual inhibitors that have shown excellent in vitro and in vivo activities against breast cancer, including triple-negative breast cancer. Herein, we summarize recent advances made in the understanding of the oncogenic functions of MDM2 and NFAT1 in breast cancer, as well as current targeting strategies and representative inhibitors. We also propose several strategies for inhibiting the NFAT1-MDM2-p53 pathway, which could be useful for developing more specific and effective inhibitors for breast cancer therapy.

GSK-3Beta-Dependent Activation of GEF-H1/ROCK Signaling Promotes LPS-Induced Lung Vascular Endothelial Barrier Dysfunction and Acute Lung Injury

The bacterial endotoxin or lipopolysaccharide (LPS) leads to the extensive vascular endothelial cells (EC) injury under septic conditions. Guanine nucleotide exchange factor-H1 (GEF-H1)/ROCK signaling not only involved in LPS-induced overexpression of pro-inflammatory mediator in ECs but also implicated in LPS-induced endothelial hyper-permeability. However, the mechanisms behind LPS-induced GEF-H1/ROCK signaling activation in the progress of EC injury remain incompletely understood. GEF-H1 localized on microtubules (MT) and is suppressed in its MT-bound state. MT disassembly promotes GEF-H1 release from MT and stimulates downstream ROCK-specific GEF activity. Since glycogen synthase kinase (GSK-3beta) participates in regulating MT dynamics under pathologic conditions, we examined the pivotal roles for GSK-3beta in modulating LPS-induced activation of GEF-H1/ROCK, increase of vascular endothelial permeability and severity of acute lung injury (ALI). In this study, we found that LPS induced human pulmonary endothelial cell (HPMEC) monolayers disruption accompanied by increase in GSK-3beta activity, activation of GEF-H1/ROCK signaling and decrease in beta-catenin and ZO-1 expression. Inhibition of GSK-3beta reduced HPMEC monolayers hyper-permeability and GEF-H1/ROCK activity in response to LPS. GSK-3beta/GEF-H1/ROCK signaling is implicated in regulating the expression of beta-catenin and ZO-1. In vivo, GSK-3beta inhibition attenuated LPS-induced activation of GEF-H1/ROCK pathway, lung edema and subsequent ALI. These findings present a new mechanism of GSK-3beta-dependent exacerbation of lung micro-vascular hyper-permeability and escalation of ALI via activation of GEF-H1/ROCK signaling and disruption of intracellular junctional proteins under septic condition.

Glycogen synthase kinase-3β ablation limits pancreatitis-induced acinar-to-ductal metaplasia

Acinar-to-ductal metaplasia (ADM) is a reversible epithelial transdifferentiation process that occurs in the pancreas in response to acute inflammation. ADM can rapidly progress towards pre-malignant pancreatic intraepithelial neoplasia (PanIN) lesions in the presence of mutant KRas and ultimately pancreatic adenocarcinoma (PDAC). In the present work, we elucidate the role and related mechanism of glycogen synthase kinase-3beta (GSK-3β) in ADM development using in vitro 3D cultures and genetically engineered mouse models. We show that GSK-3β promotes TGF-α-induced ADM in 3D cultured primary acinar cells, whereas deletion of GSK-3β attenuates caerulein-induced ADM formation and PanIN progression in Kras^G12D transgenic mice. Furthermore, we demonstrate that GSK-3β ablation influences ADM formation and PanIN progression by suppressing oncogenic KRas-driven cell proliferation. Mechanistically, we show that GSK-3β regulates proliferation by increasing the activation of S6 kinase. Taken together, these results indicate that GSK-3β participates in early pancreatitis-induced ADM and thus could be a target for the treatment of chronic pancreatitis and the prevention of PDAC progression. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Cell cycle and apoptosis regulation by NFAT transcription factors: new roles for an old player

The NFAT (nuclear factor of activated T cells) family of transcription factors consists of four Ca²⁺-regulated members (NFAT1–NFAT4), which were first described in T lymphocytes. In addition to their well-documented role in T lymphocytes, where they control gene expression during cell activation and differentiation, NFAT proteins are also expressed in a wide range of cells and tissue types and regulate genes involved in cell cycle, apoptosis, angiogenesis and metastasis. The NFAT proteins share a highly conserved DNA-binding domain (DBD), which allows all NFAT members to bind to the same DNA sequence in enhancers or promoter regions. The same DNA-binding specificity suggests redundant roles for the NFAT proteins, which is true during the regulation of some genes such as IL-2 and p21. However, it has become increasingly clear that different NFAT proteins and even isoforms can have unique functions. In this review, we address the possible reasons for these distinct roles, particularly regarding N- and C-terminal transactivation regions (TADs) and the partner proteins that interact with these TADs. We also discuss the genes regulated by NFAT during cell cycle regulation and apoptosis and the role of NFAT during tumorigenesis.