Is 5´-AMP-Activated Protein Kinase Both Jekyll and Hyde in Bladder Cancer?

Anti-cancer activity of the combination of cabozantinib and temozolomide in uterine sarcoma

PURPOSE

To evaluate the anti-cancer effects of cabozantinib, temozolomide, and their combination in uterine sarcoma cell lines and mouse xenograft models.

EXPERIMENTAL DESIGN

Human uterine sarcoma cell lines (SK-LMS-1, SK-UT-1, MES-SA, and SKN) were used to evaluate the anti-cancer activity of cabozantinib, temozolomide, and their combination. The optimal dose of each drug was determined by MTT assay. Cell proliferation and apoptosis were assessed 48 hours and 72 hours after the drug treatments. The tumor weights were measured in an SK-LMS-1 xenograft mouse model and a patient-derived xenograft (PDX) model of leiomyosarcoma treated with cabozantinib, temozolomide, or both.

RESULTS

Given individually, cabozantinib and temozolomide each significantly decreased the growth and viability of cells. This inhibitory effect was more pronounced when cabozantinib (0.50 µM) and temozolomide (0.25 mM or 0.50 mM) were co-administered (p-value < 0.05). The combination of the drugs also significantly increased apoptosis in all cells. Moreover, this effect was consistently observed in patient-derived leiomyosarcoma cells. In vivo studies with SK-LMS-1 cell xenografts and the PDX model with leiomyosarcoma demonstrated that combined treatment with cabozantinib (5 mg/kg/day, per os administration) and temozolomide (5 mg/kg/day, per os administration) synergistically decreased tumor growth (both p-values < 0.05).

CONCLUSION

The addition of cabozantinib to temozolomide offers synergistic anti-cancer effects in uterine sarcoma cell lines and xenograft mouse models, including PDX. These results warrant further investigation in a clinical trial.

The role of AMPK/mTOR signaling pathway in anticancer activity of metformin

Metformin (MTF) is a widely used drug for the treatment of diabetes mellitus type 2 (DM2) and frequently used as an adjuvant therapy for polycystic ovarian syndrome, metabolic syndrome, and in some cases also tuberculosis. Its protective effect on the cardiovascular system has also been described. Recently, MTF was subjected to various analyzes and studies that showed its beneficial effects in cancer treatment such as reducing cancer cell proliferation, reducing tumor growth, inducing apoptosis, reducing cancer risk in diabetic patients, or reducing likelihood of relapse. One of the MTF's mechanisms of action is the activation of adenosine-monophosphate-activated protein kinase (AMPK). Several studies have shown that AMPK/mammalian target of rapamycin (mTOR) pathway has anticancer effect in vivo and in vitro. The aim of this review is to present the anticancer activity of MTF highlighting the importance of the AMPK/mTOR pathway in the cancer process.

Prognostic value of CLIC3 mRNA overexpression in bladder cancer

Background

Human intracellular chloride channel 3 (CLIC3) is involved in the development of various cancers, but the expression and prognostic value of CLIC3 mRNA in bladder cancer (BC) remain unclear.

Methods

The gene expression data and clinical information of CLIC3 were obtained from the Gene Expression Omnibus (GEO) database and verified in the Oncomine and The Cancer Genome Atlas (TCGA) database. The expression of CLIC3 mRNA in BC tissues and adjacent normal tissues was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The Kaplan-Meier method was used to analyze the relationship between the expression of CLIC3 mRNA and the prognosis of BC. Cox univariate and multivariate analyses were performed on the overall survival and tumor-specific survival of BC patients. The genes coexpressed with CLIC3 were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). CLIC3-related signal transduction pathways in BC were explored with gene set enrichment analysis (GSEA).

Results

The expression of CLIC3 mRNA in BC tissues was higher than that in normal tissues (P < 0.01). High CLIC3 mRNA expression was associated with age (P = 0.021) and grade (P = 0.045) in BC patients. High CLIC3 mRNA expression predicted a poor prognosis in BC patients (P < 0.05). Cox univariate and multivariate analyses showed that high CLIC3 mRNA expression was associated with tumor-specific survival in BC patients (P < 0.05). Functional enrichment analyses indicated that CLIC3 may be significantly associated with the cell cycle, focal adhesion, the extracellular matrix (ECM) receptor interaction and the P53 signaling pathway.

Conclusions

CLIC3 mRNA is highly expressed in BC, and its high expression is related to the adverse clinicopathological factors and prognosis of BC patients. CLIC3 can be used as a biomarker for the prognosis of BC patients.

Looking to the metabolic landscapes for prostate health monitoring

Abnormal metabolism is a widely accepted biological signature of prostatic diseases, including prostate cancer and benign prostate hyperplasia. Recently accumulated epidemiological and experimental evidence illustrate that the metabolic syndrome, impaired mitochondrial function, and prostatic pathological conditions intersect. The perturbed metabolism and metabolic mediates influence key signaling pathways in various prostatic pathological conditions. This short review article aids to highlight recent findings on metabolism, metabolic mechanisms, and mitochondrial metabolism as a possible route to finding a cure for prostate diseases, including prostate cancer. The effort to better understand the role that mitochondria plays in cancer metabolism and the biological meaning of defective and/or deleted mitochondrial DNA in cancer will also be discussed.

AMPKα Is Suppressed in Bladder Cancer through Macrophage-Mediated Mechanisms

Bladder cancer presents as either low- or high-grade disease, each with distinct mutational profiles; however, both display prominent mTORC1 activation. One major negative regulator of mTORC1 is AMPK, which is a critical metabolic regulator that suppresses cellular growth in response to metabolic stress by negatively regulating mTORC1. Alterations in the activation and protein levels of AMPK have been reported in breast, gastric, and hepatocellular carcinoma. To investigate whether AMPK suppression is responsible for mTOR activation in bladder cancer, the levels of AMPKα were quantified in a cohort of primary human bladder cancers and adjacent nontumor tissues. The levels of p-AMPKα, AMPKα1, AMPKα2, and total AMPKα were significantly suppressed in both low- and high-grade disease when compared with nontumor tissue. To elucidate the AMPKα suppression mechanism, we focused on inflammation, particularly tumor-infiltrating macrophages, due to their reported role in regulating AMPK expression. Treatment of HTB2 cancer cells with varying doses of differentiated U937 macrophage conditioned medium (CM) demonstrated a dose-dependent reduction of AMPKα protein. Additionally, macrophage CM treatment of HTB2 and HT1376 bladder cells for various times also reduced AMPKα protein but not mRNA levels. Direct TNFα treatment also suppressed AMPKα at the protein but not RNA level. Finally, staining of the human cohort for CD68, a macrophage marker, revealed that CD68+ cell counts correlated with reduced AMPKα levels. In summary, these data demonstrate the potential role for inflammation and inflammatory cytokines in regulating the levels of AMPKα and promoting mTORC1 activation in bladder cancer.

Activation of AMPKα mediates additive effects of solamargine and metformin on suppressing MUC1 expression in castration-resistant prostate cancer cells

Prostate cancer is the second most common cause of cancer-related deaths worldwide. The mucin 1 (MUC1) oncoprotein is highly expressed in human prostate cancers with aggressive features. However, the role for MUC1 in occurrence and progression of castration-resistant prostate cancer (CRPC) remained elusive. In this study, we showed that solamargine, a major steroidal alkaloid glycoside, inhibited the growth of CRPC cells, which was enhanced in the presence of metformin. Furthermore, we found that solamargine increased phosphorylation of AMPKα, whereas reducing the protein expression and promoter activity of MUC1. A greater effect was observed in the presence of metformin. In addition, solamargine reduced NF-κB subunit p65 protein expression. Exogenously expressed p65 resisted solamargine-reduced MUC1 protein and promoter activity. Interestingly, exogenously expressed MUC1 attenuated solamargine-stimulated phosphorylation of AMPKα and, more importantly reversed solamargine-inhibited cell growth. Finally, solamargine increased phosphorylation of AMPKα, while inhibiting MUC1, p65 and tumor growth were observed in vivo. Overall, our results show that solamargine inhibits the growth of CRPC cells through AMPKα-mediated inhibition of p65, followed by reduction of MUC1 expression in vitro and in vivo. More importantly, metformin facilitates the antitumor effect of solamargine on CRPC cells.