Epithelial-Mesenchymal Transition Phenotype, Metformin, and Survival for Colorectal Cancer Patients with Diabetes Mellitus II

Metformin: A Dual-Role Player in Cancer Treatment and Prevention

Cancer continues to pose a significant global health challenge, as evidenced by the increasing incidence rates and high mortality rates, despite the advancements made in chemotherapy. The emergence of chemoresistance further complicates the effectiveness of treatment. However, there is growing interest in the potential of metformin, a commonly prescribed drug for type 2 diabetes mellitus (T2DM), as an adjuvant chemotherapy agent in cancer treatment. Although the precise mechanism of action of metformin in cancer therapy is not fully understood, it has been found to have pleiotropic effects, including the modulation of metabolic pathways, reduction in inflammation, and the regulation of cellular proliferation. This comprehensive review examines the anticancer properties of metformin, drawing insights from various studies conducted in vitro and in vivo, as well as from clinical trials and observational research. This review discusses the mechanisms of action involving both insulin-dependent and independent pathways, shedding light on the potential of metformin as a therapeutic agent for different types of cancer. Despite promising findings, there are challenges that need to be addressed, such as conflicting outcomes in clinical trials, considerations regarding dosing, and the development of resistance. These challenges highlight the importance of further research to fully harness the therapeutic potential of metformin in cancer treatment. The aims of this review are to provide a contemporary understanding of the role of metformin in cancer therapy and identify areas for future exploration in the pursuit of effective anticancer strategies.

The effect of metformin on the survival of colorectal cancer patients with type 2 diabetes mellitus

Evidence from previous studies suggests a protective effect of metformin in patients with colorectal cancer (CRC). The aim of this study was to examine the associations between metformin use and overall survival (OS) and disease-free survival (DFS) in CRC patients with type 2 diabetes mellitus (DM). We retrospectively included patients who underwent surgery for CRC at Limoges’ University Hospital between 2005 and 2019 and diagnosed with type 2 DM. Data on the characteristics of patients, CRC, comorbidities and drug exposure were collected from the electronic medical records. The exposure was the use of metformin and the outcomes were OS and DFS. We identified 290 CRC patients with type 2 DM. A total of 144 (49.7%) of them were treated with metformin. Metformin users were significantly younger, with higher body mass index and less diabetes-related complications compared to non-users. The 2-year OS was significantly higher in metformin users than in non-users (86.9 ± 2.9% vs. 71.0 ± 4.0%, p = 0.001). In multivariate analysis, metformin use was associated with better OS (adjusted hazard ratios [aHR] = 0.45 95% confidence interval [95% CI]: 0.21–0.96) and better DFS (aHR = 0.31; 95% CI: 0.18–0.54). In conclusion, the use of metformin may improve OS and DFS in CRC patients with type 2 DM.

Effect of E-cadherin on Prognosis of Colorectal Cancer: A Meta-Analysis Update

PURPOSE

The effect of E-cadherin on colorectal cancer is still controversial. In order to clarify the effect of E-cadherin on the prognosis and clinicopathological features of colorectal cancer, a meta-analysis was conducted.

METHODS

PubMed, Embase and Cochrane Library were used to collect all relevant literature published before November 2021, and the corresponding data was extracted to analyze the correlation between the expression of E-cadherin and the prognosis and clinicopathological features of colorectal cancer. In addition, the Gene Expression Profiling Interactive Analysis (GEPIA) was used to validate our results.

RESULTS

Fifty-two studies, including 9591 patients, were included in this meta-analysis. According to the meta-analysis, low expression of E-cadherin was significantly associated with shorter overall survival (OS) (hazard ratio [HR] 2.09, 95% confidence interval [CI]1.67-2.62; Z = 6.42, p = 0.000) and disease-free survival (DFS) (HR 2.03, 95% CI 1.71-2.42; Z = 7.95, p = 0.000). In addition, low expression of E-cadherin resulted in higher risk of low differentiation (odds ratio [OR] 0.35, 95% CI 0.25-0.50; p = 0.000), high risk of distant metastasis (OR 0.45, 95% CI 0.35-0.58; p = 0.000), high risk of vascular invasion (OR 0.61, 95% CI 0.45-0.83; p = 0.002), higher risk of lymph node metastasis (OR 0.54, 95% CI 0.42-0.69; p = 0.000), high risk of lymphatic invasion (OR 0.56, 95% CI 0.40-0.80; p = 0.001), high risk of deep infiltration (OR 0.63, 95% CI 0.50-0.80; p = 0.000), later TNM stage (OR 0.60, 95% CI 0.46-0.78; p = 0.000) and late Dukes' stage (OR 0.35,95% CI 0.25-0.49; p = 0.000), but wasn't associated with tumor size (OR 0.90, 95% CI 0.71-1.15; p = 0.406).The results of GEPIA showed that E-cadherin mRNA expression in colorectal cancer tumor tissues and normal tissues had no difference, and had no effect on OS and DFS.

CONCLUSION

Although not supported by GEPIA, our meta-analysis provided abundant data to suggest that low expression of E-cadherin is associated with poor prognosis in colorectal cancer patients and is an important factor influencing adverse clinicopathological features. Therefore, E-cadherin may be used to predict the prognosis of colorectal cancer and provide guidance for clinical treatment.

Metformin exerts anti-cancerogenic effects and reverses epithelial-to-mesenchymal transition trait in primary human intrahepatic cholangiocarcinoma cells

Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive cancer with marked resistance to chemotherapeutics without therapies. The tumour microenvironment of iCCA is enriched of Cancer-Stem-Cells expressing Epithelial-to-Mesenchymal Transition (EMT) traits, being these features associated with aggressiveness and drug resistance. Treatment with the anti-diabetic drug Metformin, has been recently associated with reduced incidence of iCCA. We aimed to evaluate the anti-cancerogenic effects of Metformin in vitro and in vivo on primary cultures of human iCCA. Our results showed that Metformin inhibited cell proliferation and induced dose- and time-dependent apoptosis of iCCA. The migration and invasion of iCCA cells in an extracellular bio-matrix was also significantly reduced upon treatments. Metformin increased the AMPK and FOXO3 and induced phosphorylation of activating FOXO3 in iCCA cells. After 12 days of treatment, a marked decrease of mesenchymal and EMT genes and an increase of epithelial genes were observed. After 2 months of treatment, in order to simulate chronic administration, Cytokeratin-19 positive cells constituted the majority of cell cultures paralleled by decreased Vimentin protein expression. Subcutaneous injection of iCCA cells previously treated with Metformin, in Balb/c-nude mice failed to induce tumour development. In conclusion, Metformin reverts the mesenchymal and EMT traits in iCCA by activating AMPK-FOXO3 related pathways suggesting it might have therapeutic implications.

Metformin and colorectal cancer: a systematic review, meta-analysis and meta-regression

PURPOSE

Metformin may have a role in reducing the incidence of colorectal cancer (CRC) and improving survival outcome. This meta-analysis explored the effect of metformin use on colorectal adenoma and cancer incidence, and colorectal oncological outcomes.

METHODS

A database search was conducted on Medline, Embase and CNKI for studies comparing metformin vs. non-metformin users, metformin users vs. non-diabetics and metformin users vs. diabetics with diet-only treatment. Meta-analysis was done with DerSimonian and Laird with risk ratios (RR), and hazard ratios (HR) for survival outcomes.

RESULTS

We included 58 studies and summarized incidences of colorectal adenoma and cancer, as well as cancer survival outcomes. Metformin users had a significant lower incidence of colorectal adenoma (RR 0.77, CI 0.67-0.88, p < 0.001), advanced adenoma (0.61, CI 0.42-0.88, p = 0.008) and CRC (RR 0.76, CI 0.69-0.84, p < 0.001) respectively compared with non-metformin users. Overall survival (HR 0.6, CI 0.53-0.67, p < 0.001) and CRC-specific survival (HR 0.66, CI 0.59-0.74, p < 0.001) were higher among metformin users compared with non-metformin users. Further analysis on overall survival of metastatic CRC patients revealed significantly higher survival rates in metformin users (HR 0.77, CI 0.68-0.87, p < 0.001).

CONCLUSION

This meta-analysis showed that metformin use significantly reduces colorectal adenoma and cancer incidence and improves colorectal cancer outcomes.

For colorectal cancer patients with type II diabetes, could metformin improve the survival rate? A meta-analysis

OBJECTIVE

Current research is controversial about whether metformin can improve the survival rate of patients with colon cancer. Therefore, we conducted a meta-analysis to identify the association between metformin and the survival rate of colorectal cancer (CRC) patients with type II diabetes.

METHODS

We conducted a search in databases including Pubmed, EMBASE and Cochrane Library. All articles were published in the last decade, and the quality of each study was evaluated by the Newcastle-Ottawa Scale. Odds ratios (ORs) and its corresponding 95% confidence intervals (CIs) for each study were calculated and summary relative risk estimates with corresponding 95% CIs were generated using the random-effects model. Heterogeneity and publication bias were assessed.

RESULTS

Ten articles were included in this meta-analysis. The included articles were all cohort studies. In a pooled analysis of all studies, metformin using was associated with increased overall survival (OS) rate (OR, 0.54; 95% CI, 0.47 to 0.63) and cancer-specific survival (CS) rate (OR 0.59; 95% CI 0.43 to 0.82) of CRC patients with diabetes. We found that the effect of metformin is associated with geographical region through subgroup meta-analysis.

CONCLUSIONS

Metformin using was associated with an increased OS rate and CS rate of colorectal cancer.

Paeoniflorin: a monoterpene glycoside from plants of Paeoniaceae family with diverse anticancer activities

OBJECTIVES

Paeoniflorin, a representative pinane monoterpene glycoside in plants of Paeoniaceae family, possesses promising anticancer activities on diverse tumours. This paper summarized the advance of Paeoniflorin on cancers in vivo and in vitro, discussed the related molecular mechanisms, as well as suggested some perspectives of the future investigations.

KEY FINDINGS

Anticancer activities of paeoniflorin have been comprehensively investigated, including liver cancer, gastric cancer, breast cancer, lung cancer, pancreatic cancer, colorectal cancer, glioma, bladder cancer and leukaemia. Furthermore, the potential molecular mechanisms corresponding to the antitumour effects of Paeoniflorin might be related to the following aspects: inhibition of tumour cell proliferation and neovascularization, induction apoptosis, and inhibition of tumour invasion and metastasis.

SUMMARY

Paeoniflorin has wide spectrum antitumour activities; however, in vivo and clinical investigations on antitumour effect of Paeoniflorin are lacking which should be focused on further studies. Our present review on antitumour effects of Paeoniflorin would be beneficial for the further molecular mechanisms study, candidate antitumour drug development and clinical research of Paeoniflorin in the future.

Metformin reverses PARP inhibitors-induced epithelial-mesenchymal transition and PD-L1 upregulation in triple-negative breast cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors have emerged as promising targeted therapies for BRCA-mutated cancers by blocking repair of DNA double-strand breaks. However, resistance to PARP inhibitors (PARPi) has been described in some patients lowering the overall response rates. To investigate the underlying mechanisms of PARPi resistance, we developed the adaptive resistant clones in triple-negative breast cancer cell lines. We identified epithelial-mesenchymal transition (EMT) and upregulation of programmed death-ligand 1 (PD-L1) in resistant cells and further demonstrated the important role of Akt S473 phosphorylation in PARPi resistance. In addition, PARPi mediated EMT is independent of PD-L1 upregulation. Blocking the p-Akt S473 axis by metformin reversed EMT and PD-L1 expression which sensitized PARPi-resistant cells to cytotoxic T cells. Thus, a combination of metformin and PARP inhibitors may be a promising therapeutic strategy to increase the efficacy of PARP inhibitors and tumor sensitivity to immunotherapy.

Metformin triggers the intrinsic apoptotic response in human AGS gastric adenocarcinoma cells by activating AMPK and suppressing mTOR/AKT signaling

Metformin is commonly used to treat patients with type 2 diabetes and is associated with a decreased risk of cancer. Previous studies have demonstrated that metformin can act alone or in synergy with certain anticancer agents to achieve anti-neoplastic effects on various types of tumors via adenosine monophosphate-activated protein kinase (AMPK) signaling. However, the role of metformin in AMPK-mediated apoptosis of human gastric cancer cells is poorly understood. In the current study, metformin exhibited a potent anti-proliferative effect and induced apoptotic characteristics in human AGS gastric adenocarcinoma cells, as demonstrated by MTT assay, morphological observation method, terminal deoxynucleotidyl transferase dUTP nick end labeling and caspase-3/7 assay kits. Western blot analysis demonstrated that treatment with metformin increased the phosphorylation of AMPK, and decreased the phosphorylation of AKT, mTOR and p70S6k. Compound C (an AMPK inhibitor) suppressed AMPK phosphorylation and significantly abrogated the effects of metformin on AGS cell viability. Metformin also reduced the phosphorylation of mitogen-activated protein kinases (ERK, JNK and p38). Additionally, metformin significantly increased the cellular ROS level and included loss of mitochondrial membrane potential (ΔΨm). Metformin altered apoptosis-associated signaling to downregulate the BAD phosphorylation and Bcl-2, pro-caspase-9, pro-caspase-3 and pro-caspase-7 expression, and to upregulate BAD, cytochrome c, and Apaf-1 proteins levels in AGS cells. Furthermore, z-VAD-fmk (a pan-caspase inhibitor) was used to assess mitochondria-mediated caspase-dependent apoptosis in metformin-treated AGS cells. The findings demonstrated that metformin induced AMPK-mediated apoptosis, making it appealing for development as a novel anticancer drug for the treating gastric cancer.

Anti-Tumor Effects of Paeoniflorin on Epithelial-To-Mesenchymal Transition in Human Colorectal Cancer Cells

Background

Colorectal cancer is one of the leading causes of death in China, and the development of effective drugs is urgently needed. Here, we report on Paeoniflorin (PF), a product isolated from the roots of the peony plant, as a possible candidate because of its anti-tumor effects on epithelial-to-mesenchymal transition (EMT) of PF in human colorectal cancer (CRC).

Material/Methods

Cell proliferation, wound healing, and Transwell assays were used to analyze the effects of PF on in vitro cell migration and invasion of HCT116 and SW480, 2 colorectal cancer cell lines. The tumor xenograft model was used to verify the anti-metastasis effects of PF in vivo. The RNA and protein levels of epithelia-cadherin (E-cadherin), Vimentin, and histone deacetylase2 (HDAC2) were measured by qPCR and Western blot analysis to explore the mechanism involved.

Results

Our results showed that PF inhibited colorectal cancer cell migration and invasion and suppressed the metastatic potential of the cancer cells in vivo. Moreover, PF significantly decreased the expression of HDAC2 and Vimentin, while increasing the expression of E-cadherin.

Conclusions

These results suggest that PF inhibits colorectal cancer cell migration and invasion ability and reverses the EMT process, through inhibiting the expression of HDAC2, and then affects the expression level of E-cadherin and Vimentin at the cell level. Our results were also verified in the tumor xenograft model. This indicates that PF may be a candidate for colorectal cancer treatment.

Metformin in cancer

Metformin is a lipophilic biguanide which inhibits hepatic gluconeogenesis and improves peripheral utilization of glucose. It is the first line pharmacotherapy for glucose control in patients with Type 2 diabetes due to its safety, efficacy and tolerability. Metformin exhibits pleotropic effects, which may have beneficial effects on a variety of tissues independent of glucose control. A potential anti-tumourigenic effect of metformin may be mediated by its role in activating AMP-kinase, which in turn inhibits mammalian target of rapamycin (mTOR). Non-AMPK dependent protective pathways may include reduction of insulin, insulin-like growth factor-1, leptin, inflammatory pathways and potentiation of adiponectin, all of which may have a role in tumourigenesis. A role in inhibiting cancer stem cells is also postulated. A number of large scale observational and cohort studies suggest metformin is associated with a reduced risk of a number of cancers, although the data is not conclusive. Recent randomised studies reporting use of metformin in treatment of cancer have revealed mixed results, and the results of much larger randomised trials of metformin as an adjuvant therapy in breast and colorectal cancers are awaited.

High Vimentin Expression Predicts a Poor Prognosis and Progression in Colorectal Cancer: A Study with Meta-Analysis and TCGA Database

The aim of this study was to evaluate the role of vimentin expression in the prognosis and progression of CRC. Meta-analysis was conducted to investigate the correlations between vimentin and prognosis and clinicopathological features in CRC. Literatures were searched by PubMed, Embase, ClinicalKey, CNKI, VIP, and WanFang databases. The Cancer Genome Atlas (TCGA) database was used to assess the association of vimentin expression with survival rate in CRC. Eleven reports with 1969 cases were included in the meta-analysis. The results showed that positive vimentin expression predicted a poor overall survival (OS) in the univariate analysis (HR: 2.087, 95%CI: 1.660-2.625) and multivariate analysis (HR: 1.633, 95%CI: 1.223-2.181). Vimentin overexpression also conferred worse disease-free survival (DFS) in the univariate analysis (HR: 2.069, 95%CI: 1.024-4.179) and multivariate analysis (HR: 2.802, 95%CI: 1.421-5.527). Moreover, upregulated vimentin is related to lymph node metastasis (OR: 2.288, 95%CI: 1.159-4.517), TNM stages (OR: 1.957, 95%CI: 1.333-2.873), and N stage (OR: 2.316, 95%CI: 1.482-3.620). Analysis of TCGA database indicated that elevated vimentin predicated a shorter OS (p=0.033). Our findings reveal that upregulated vimentin contributes to the progression and poor prognosis of CRC. Vimentin may be a prognostic biomarker and therapeutic target in patients with CRC.

Personalized Proteomics in Proliferative Vitreoretinopathy Implicate Hematopoietic Cell Recruitment and mTOR as a Therapeutic Target

PURPOSE

To profile vitreous cytokine expression of proliferative vitreoretinopathy (PVR) patients.

DESIGN

Case-control study.

METHODS

Liquid biopsies were collected from 2 groups: control subjects (n = 3) undergoing pars plana vitrectomy to remove an epiretinal membrane (ERM), and test subjects (n = 7) with varying degrees of PVR. A high-throughput cytokine screen measured expression of 200 cytokines. Cytokine expression patterns were prospectively validated in separate cohorts of control patients and those with PVR-A, PVR-B, and PVR-C (n = 10 for each group). Expression changes were evaluated by analysis of variance (significant P value < .05), hierarchical cluster algorithm, and pathway analysis, to identify candidate pathways for prospective studies.

RESULTS

In PVR vitreous, 29 cytokines were upregulated compared to controls. Early PVR vitreous showed upregulation of T-cell markers, profibrotic cytokines, and cytokines downstream of mTOR activation (IL-2, IL-6, and IL-13), whereas in late PVR vitreous, cytokines driving monocyte responses and stem-cell recruitment (SDF-1) prevailed. Prospective validation confirmed the differential expression of specific cytokines from PVR-A to C.

CONCLUSIONS

Early PVR is characterized by activation of T cells and mTOR signaling, whereas advanced PVR is characterized by a chronic monocyte response. PVR might be treated by rational repositioning of existing drugs that target mTOR and IL-6. Our analysis demonstrates that successful therapeutic intervention will be highly dependent on the specific therapeutic target and the stage of PVR. This study provides insights into cytokines that will serve as biomarkers and therapeutic targets. These biomarkers will help design clinical trials that intervene at appropriate times.