The role of glycogen synthase kinase 3 (GSK3) in cancer with emphasis on ovarian cancer development and progression: A comprehensive review

Unlocking hope: GSK-3 inhibitors and Wnt pathway activation in Alzheimer's therapy

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterised by progressive cognitive decline and the accumulation of amyloid-β plaques and tau tangles. The Wnt signalling pathway known for its crucial role in neurodevelopment and adult neurogenesis has emerged as a potential target for therapeutic intervention in AD. Glycogen synthase kinase-3 beta (GSK-3β), a key regulator of the Wnt pathway, plays a pivotal role in AD pathogenesis by promoting tau hyperphosphorylation and neuroinflammation. Several preclinical studies have demonstrated that inhibiting GSK-3β leads to the activation of Wnt pathway thereby promoting neuroprotective effects, and mitigating cognitive deficits in AD animal models. The modulation of Wnt signalling appears to have multifaceted benefits including the reduction of amyloid-β production, tau hyperphosphorylation, enhancement of synaptic plasticity, and inhibition of neuroinflammation. These findings suggest that targeting GSK-3β to activate Wnt pathway may represent a novel approach for slowing or halting the progression of AD. This hypothesis reviews the current state of research exploring the activation of Wnt pathway through the inhibition of GSK-3β as a promising therapeutic strategy in AD.

The scaffold protein disabled 2 (DAB2) and its role in tumor development and progression

BACKGROUND

Disabled 2 (DAB2) is a multifunctional protein that has emerged as a critical component in the regulation of tumor growth. Its dysregulation is implicated in various types of cancer, underscoring its importance in understanding the molecular mechanisms underlying tumor development and progression. This review aims to unravel the intricate molecular mechanisms by which DAB2 exerts its tumor-suppressive functions within cancer signaling pathways.

METHODS AND RESULTS

We conducted a comprehensive review of the literature focusing on the structure, expression, physiological functions, and tumor-suppressive roles of DAB2. We provide an overview of the structure, expression, and physiological functions of DAB2. Evidence supporting DAB2's role as a tumor suppressor is explored, highlighting its ability to inhibit cell proliferation, induce apoptosis, and modulate key signaling pathways involved in tumor suppression. The interaction between DAB2 and key oncogenes is examined, elucidating the interplay between DAB2 and oncogenic signaling pathways. We discuss the molecular mechanisms underlying DAB2-mediated tumor suppression, including its involvement in DNA damage response and repair, regulation of cell cycle progression and senescence, and modulation of epithelial-mesenchymal transition (EMT). The review explores the regulatory networks involving DAB2, covering post-translational modifications, interactions with other tumor suppressors, and integration within complex signaling networks. We also highlight the prognostic significance of DAB2 and its role in pre-clinical studies of tumor suppression.

CONCLUSION

This review provides a comprehensive understanding of the molecular mechanisms by which DAB2 exerts its tumor-suppressive functions. It emphasizes the significance of DAB2 in cancer signaling pathways and its potential as a target for future therapeutic interventions.

Quercetin as a Promising Antiprotozoan Phytochemical: Current Knowledge and Future Research Avenues

Despite tremendous advances in the prevention and treatment of infectious diseases, only few antiparasitic drugs have been developed to date. Protozoan infections such as malaria, leishmaniasis, and trypanosomiasis continue to exact an enormous toll on public health worldwide, underscoring the need to discover novel antiprotozoan drugs. Recently, there has been an explosion of research into the antiprotozoan properties of quercetin, one of the most abundant flavonoids in the human diet. In this review, we tried to consolidate the current knowledge on the antiprotozoal effects of quercetin and to provide the most fruitful avenues for future research. Quercetin exerts potent antiprotozoan activity against a broad spectrum of pathogens such as Leishmania spp., Trypanosoma spp., Plasmodium spp., Cryptosporidium spp., Trichomonas spp., and Toxoplasma gondii. In addition to its immunomodulatory roles, quercetin disrupts mitochondrial function, induces apoptotic/necrotic cell death, impairs iron uptake, inhibits multiple enzymes involved in fatty acid synthesis and the glycolytic pathways, suppresses the activity of DNA topoisomerases, and downregulates the expression of various heat shock proteins in these pathogens. In vivo studies also show that quercetin is effective in reducing parasitic loads, histopathological damage, and mortality in animals. Future research should focus on designing effective drug delivery systems to increase the oral bioavailability of quercetin. Incorporating quercetin into various nanocarrier systems would be a promising approach to manage localized cutaneous infections. Nevertheless, clinical trials are needed to validate the efficacy of quercetin in treating various protozoan infections.

γ-aminobutyric acid B2 receptor: A potential therapeutic target for cholangiocarcinoma in patients with diabetes mellitus

BACKGROUND

The association between diabetes mellitus (DM) and the increased risk and progression of cholangiocarcinoma (CCA) has been reported with unclear underlying mechanisms. Previous studies showed that γ-aminobutyric acid (GABA) B2 receptor (GABBR2) was upregulated in CCA cells cultured in high glucose (HG) conditions. Roles of GABA receptors in CCA progression have also been studied, but their association with DM and hyperglycemia in CCA remains unclarified.

AIM

To investigate the effects of hyperglycemia on GABBR2 expression and the potential use of GABBR2 as a CCA therapeutic target.

METHODS

CCA cells, KKU-055 and KKU-213A, were cultured in Dulbecco Modified Eagle's Medium supplemented with 5.6 mmol/L (normal glucose, NG) or 25 mmol/L (HG) glucose and assigned as NG and HG cells, respectively. GABBR2 expression in NG and HG cells was investigated using real-time quantitative polymerase chain reaction and western blot. Expression and localization of GABBR2 in CCA cells were determined using immunocytofluorescence. GABBR2 expression in tumor tissues from CCA patients with and without DM was studied using immunohistochemistry, and the correlations of GABBR2 with the clinicopathological characteristics of patients were analyzed using univariate analysis. Effects of baclofen, a GABA-B receptor agonist, on CCA cell proliferation and clonogenicity were tested using the MTT and clonogenic assays. Phospho-kinases arrays were used to screen the affected signaling pathways after baclofen treatment, and the candidate signaling molecules were validated using the public transcriptomic data and western blot.

RESULTS

GABBR2 expression in CCA cells was induced by HG in a dose- and time-dependent manner. CCA tissues from patients with DM and hyperglycemia also showed a significantly higher GABBR2 expression compared with tumor tissues from those with euglycemia (P < 0.01). High GABBR2 expression was significantly associated with a poorer non-papillary histological subtype but with smaller sizes of CCA tumors (P < 0.05). HG cells of both tested CCA cell lines were more sensitive to baclofen treatment. Baclofen significantly suppressed the proliferation and clonogenicity of CCA cells in both NG and HG conditions (P < 0.05). Phospho-kinase arrays suggested glycogen synthase kinase 3 (GSK3), β-catenin, and the signal transducer and activator of transcription 3 (STAT3) as candidate signaling molecules under the regulation of GABBR2, which were verified in NG and HG cells of the individual CCA cell lines. Cyclin D1 and c-Myc, the common downstream targets of GSK3/β-catenin and STAT3 involving cell proliferation, were accordingly downregulated after baclofen treatment.

CONCLUSION

GABBR2 is upregulated by HG and holds a promising role as a therapeutic target for CCA regardless of the glucose condition.

LCRMP-1 is required for spermatogenesis and stabilises spermatid F-actin organization via the PI3K-Akt pathway

Long-form collapsin response mediator protein-1 (LCRMP-1) belongs to the CRMP family which comprises brain-enriched proteins responsible for axon guidance. However, its role in spermatogenesis remains unclear. Here we find that LCRMP-1 is abundantly expressed in the testis. To characterize its physiological function, we generate LCRMP-1-deficient mice (Lcrmp-1^-/-). These mice exhibit aberrant spermiation with apoptotic spermatids, oligospermia, and accumulation of immature testicular cells, contributing to reduced fertility. In the seminiferous epithelial cycle, LCRMP-1 expression pattern varies in a stage-dependent manner. LCRMP-1 is highly expressed in spermatids during spermatogenesis and especially localized to the spermiation machinery during spermiation. Mechanistically, LCRMP-1 deficiency causes disorganized F-actin due to unbalanced signaling of F-actin dynamics through upregulated PI3K-Akt-mTOR signaling. In conclusion, LCRMP-1 maintains spermatogenesis homeostasis by modulating cytoskeleton remodeling for spermatozoa release.

GSK3β mediates the spatiotemporal dynamics of NLRP3 inflammasome activation

Subcellular machinery of NLRP3 is essential for inflammasome assembly and activation. However, the stepwise process and mechanistic basis of NLRP3 engagement with organelles remain unclear. Herein, we demonstrated glycogen synthase kinase 3β (GSK3β) as a molecular determinant for the spatiotemporal dynamics of NLRP3 inflammasome activation. Using live cell multispectral time-lapse tracking acquisition, we observed that upon stimuli NLRP3 was transiently associated with mitochondria and subsequently recruited to the Golgi network (TGN) where it was retained for inflammasome assembly. This occurred in relation to the temporal contact of mitochondria to Golgi apparatus. NLRP3 stimuli initiate GSK3β activation with subsequent binding to NLRP3, facilitating NLRP3 recruitment to mitochondria and transition to TGN. GSK3β activation also phosphorylates phosphatidylinositol 4-kinase 2 Α (PI4k2A) in TGN to promote sustained NLRP3 oligomerization. Our study has identified the interplay between GSK3β signaling and the organelles dynamics of NLRP3 required for inflammasome activation and opens new avenues for therapeutic intervention.

SCAMP3 Regulates EGFR and Promotes Proliferation and Migration of Triple-Negative Breast Cancer Cells through the Modulation of AKT, ERK, and STAT3 Signaling Pathways

Triple-negative breast cancer (TNBC) is the most aggressive, metastatic, and lethal breast cancer subtype. To improve the survival of TNBC patients, it is essential to explore new signaling pathways for the further development of effective drugs. This study aims to investigate the role of the secretory carrier membrane protein 3 (SCAMP3) in TNBC and its association with the epidermal growth factor receptor (EGFR). Through an internalization assay, we demonstrated that SCAMP3 colocalizes and redistributes EGFR from the cytoplasm to the perinucleus. Furthermore, SCAMP3 knockout decreased proliferation, colony and tumorsphere formation, cell migration, and invasion of TNBC cells. Immunoblots and degradation assays showed that SCAMP3 regulates EGFR through its degradation. In addition, SCAMP3 modulates AKT, ERK, and STAT3 signaling pathways. TNBC xenograft models showed that SCAMP3 depletion delayed tumor cell proliferation at the beginning of tumor development and modulated the expression of genes from the PDGF pathway. Additionally, analysis of TCGA data revealed elevated SCAMP3 expression in breast cancer tumors. Finally, patients with TNBC with high expression of SCAMP3 showed decreased RFS and DMFS. Our findings indicate that SCAMP3 could contribute to TNBC development through the regulation of multiple pathways and has the potential to be a target for breast cancer therapy.

Celastrol with a Knockdown of miR-9-2, miR-17 and miR-19 Causes Cell Cycle Changes and Induces Apoptosis and Autophagy in Glioblastoma Multiforme Cells

Glioblastoma multiforme (GBM) is a cancer with extremely high aggressiveness, malignancy and mortality. Because of all of the poor prognosis features of GBM, new methods should be sought that will effectively cure it. We examined the efficacy of a combination of celastrol and a knockdown of the miR-9-2, miR-17 and miR-19 genes in the human glioblastoma U251MG cell line. U251MG cells were transfected with specific siRNA and exposed to celastrol. The effect of the knockdown of the miRs genes in combination with exposure to celastrol on the cell cycle (flow cytometry) and the expression of selected genes related to its regulation (RT-qPCR) and the regulation of apoptosis and autophagy was investigated. We found a significant reduction in cell viability and proliferation, an accumulation of the subG1-phase cells and a decreased population of cells in the S and G2/M phases, as well as the induction of apoptosis and autophagy. The observed changes were not identical in the case of the silencing of each of the tested miRNAs, which indicates a different mechanism of action of miR9-2, miR-17, miR-19 silencing on GBM cells in combination with celastrol. The multidirectional effects of the silencing of the genes encoding miR-9-2, miR-17 and miR-19 in combination with exposure to celastrol is possible. The studied strategy of silencing the miR overexpressed in GBM could be important in developing more effective treatments for glioblastoma. Additional studies are necessary in order to obtain a more detailed interpretation of the obtained results. The siRNA-induced miR-9-2, miR-17 and miR-19 mRNA knockdowns in combination with celastrol could offer a novel therapeutic strategy to more effectively control the growth of human GBM cells.

Wnt/β-Catenin Inhibition Disrupts Carboplatin Resistance in Isogenic Models of Triple-Negative Breast Cancer

Triple-Negative Breast Cancer (TNBC) is the most aggressive breast cancer subtype, characterized by limited treatment options and higher relapse rates than hormone-receptor-positive breast cancers. Chemotherapy remains the mainstay treatment for TNBC, and platinum salts have been explored as a therapeutic alternative in neo-adjuvant and metastatic settings. However, primary and acquired resistance to chemotherapy in general and platinum-based regimens specifically strongly hampers TNBC management. In this study, we used carboplatin-resistant in vivo patient-derived xenograft and isogenic TNBC cell-line models and detected enhanced Wnt/β-catenin activity correlating with an induced expression of stem cell markers in both resistant models. In accordance, the activation of canonical Wnt signaling in parental TNBC cell lines increases stem cell markers' expression, formation of tumorspheres and promotes carboplatin resistance. Finally, we prove that Wnt signaling inhibition resensitizes resistant models to carboplatin both in vitro and in vivo, suggesting the synergistic use of Wnt inhibitors and carboplatin as a therapeutic option in TNBC. Here we provide evidence for a prominent role of Wnt signaling in mediating resistance to carboplatin, and we establish that combinatorial targeting of Wnt signaling overcomes carboplatin resistance enhancing chemotherapeutic drug efficacy.

Methylation Patterns of DKK1, DKK3 and GSK3β Are Accompanied with Different Expression Levels in Human Astrocytoma

In the present study, we investigated genetic and epigenetic changes and protein expression levels of negative regulators of Wnt signaling, DKK1, DKK3, and APC as well as glycogen synthase kinase 3 (GSK3β) and β-catenin in 64 human astrocytomas of grades II-IV. Methylation-specific PCR revealed promoter methylation of DKK1, DKK3, and GSK3β in 38%, 43%, and 18% of samples, respectively. Grade IV comprised the lowest number of methylated GSK3β cases and highest of DKK3. Evaluation of the immunostaining using H-score was performed for β-catenin, both total and unphosphorylated (active) forms. Additionally, active (pY216) and inactive (pS9) forms of GSK3β protein were also analyzed. Spearman's correlation confirmed the prevalence of β-catenin's active form (r_s = 0.634, p < 0.001) in astrocytoma tumor cells. The Wilcoxon test revealed that astrocytoma with higher levels of the active pGSK3β-Y216 form had lower expression levels of its inactive form (p < 0.0001, Z = -5.332). Changes in APC's exon 11 were observed in 44.44% of samples by PCR/RFLP. Astrocytomas with changes of APC had higher H-score values of total β-catenin compared to the group without genetic changes (t = -2.264, p = 0.038). Furthermore, a positive correlation between samples with methylated DKK3 promoter and the expression of active pGSK3β-Y216 (r_s = 0.356, p = 0.011) was established. Our results emphasize the importance of methylation for the regulation of Wnt signaling. Large deletions of the APC gene associated with increased β-catenin levels, together with oncogenic effects of both β-catenin and GSK3β, are clearly involved in astrocytoma evolution. Our findings contribute to a better understanding of the etiology of gliomas. Further studies should elucidate the clinical and therapeutic relevance of the observed molecular alterations.

Isoorientin Inhibits Inflammation in Macrophages and Endotoxemia Mice by Regulating Glycogen Synthase Kinase 3β

Isoorientin has anti-inflammatory effects; however, the mechanism remains unclear. We previously found isoorientin is an inhibitor of glycogen synthase kinase 3β (GSK3β) in vitro. Overactivation of GSK3β is associated with inflammatory responses. GSK3β is inactivated by phosphorylation at Ser9 (i.e., p-GSK3β). Lithium chloride (LiCl) inhibits GSK3β and also increases p-GSK3β (Ser9). The present study investigated the anti-inflammatory effect and mechanism of isoorientin via GSK3β regulation in lipopolysaccharide- (LPS-) induced RAW264.7 murine macrophage-like cells and endotoxemia mice. LiCl was used as a control. While AKT phosphorylates GSK3β, MK-2206, a selective AKT inhibitor, was used to activate GSK3β via AKT inhibition (i.e., not phosphorylate GSK3β at Ser9). The proinflammatory cytokines TNF-α, IL-6, and IL-1β were detected by ELISA or quantitative real-time PCR, while COX-2 by Western blotting. The p-GSK3β and GSK3β downstream signal molecules, including NF-κB, ERK, Nrf2, and HO-1, as well as the tight junction proteins ZO-1 and occludin were measured by Western blotting. The results showed that isoorientin decreased the production of TNF-α, IL-6, and IL-1β and increased the expression of p-GSK3β in vitro and in vivo, similar to LiCl. Coadministration of isoorientin and LiCl showed antagonistic effects. Isoorientin decreased the expression of COX-2, inhibited the activation of ERK and NF-κB, and increased the activation of Nrf2/HO-1 in LPS-induced RAW264.7 cells. Isoorientin increased the expressions of occludin and ZO-1 in the brain of endotoxemia mice. In summary, isoorientin can inhibit GSK3β by increasing p-GSK3β and regulate the downstream signal molecules to inhibit inflammation and protect the integrity of the blood-brain barrier and the homeostasis in the brain.