Fer and FerT Govern Mitochondrial Susceptibility to Metformin and Hypoxic Stress in Colon and Lung Carcinoma Cells

​Comprehensive mendelian randomization analysis of plasma proteomics to identify new therapeutic targets for the treatment of coronary heart disease and myocardial infarction

BACKGROUND

Ischemic heart disease is one of the leading causes of mortality worldwide, and thus calls for development of more effective therapeutic strategies. This study aimed to identify potential therapeutic targets for coronary heart disease (CHD) and myocardial infarction (MI) by investigating the causal relationship between plasma proteins and these conditions.

METHODS

A two-sample Mendelian randomization (MR) study was performed to evaluate more than 1600 plasma proteins for their causal associations with CHD and MI. The MR findings were further confirmed through Bayesian colocalization, Summary-data-based Mendelian Randomization (SMR), and Transcriptome-Wide Association Studies (TWAS) analyses. Further analyses, including enrichment analysis, single-cell analysis, MR analysis of cardiovascular risk factors, phenome-wide Mendelian Randomization (Phe-MR), and protein-protein interaction (PPI) network construction were conducted to verify the roles of selected causal proteins.

RESULTS

Thirteen proteins were causally associated with CHD, seven of which were also causal for MI. Among them, FES and PCSK9 were causal proteins for both diseases as determined by several analytical methods. PCSK9 was a risk factor of CHD (OR = 1.25, 95% CI: 1.13-1.38, P = 7.47E-06) and MI (OR = 1.36, 95% CI: 1.21-1.54, P = 2.30E-07), whereas FES was protective against CHD (OR = 0.68, 95% CI: 0.59-0.79, P = 6.40E-07) and MI (OR = 0.65, 95% CI: 0.54-0.77, P = 5.38E-07). Further validation through enrichment and single-cell analysis confirmed the causal effects of these proteins. Moreover, MR analysis of cardiovascular risk factors, Phe-MR, and PPI network provided insights into the potential drug development based on the proteins.

CONCLUSIONS

This study investigated the causal pathways associated with CHD and MI, highlighting the protective and risk roles of FES and PCSK9, respectively. FES. Specifically, the results showed that these proteins are promising therapeutic targets for future drug development.

The Role and Mechanism of Metformin in Inflammatory Diseases

Metformin is a classical drug used to treat type 2 diabetes. With the development of research on metformin, it has been found that metformin also has several advantages aside from its hypoglycemic effect, such as anti-inflammatory, anti-aging, anti-cancer, improving intestinal flora, and other effects. The prevention of inflammation is critical because chronic inflammation is associated with numerous diseases of considerable public health. Therefore, there has been growing interest in the role of metformin in treating various inflammatory conditions. However, the precise anti-inflammatory mechanisms of metformin were inconsistent in the reported studies. Thus, this review aims to summarize various currently known possible mechanisms of metformin involved in inflammatory diseases and provide references for the clinical application of metformin.

Metformin and thymoquinone co-treatment enhance 5-fluorouracil cytotoxicity by suppressing the PI3K/mTOR/HIF1α pathway and increasing oxidative stress in colon cancer cells

This study investigated the chemotherapeutic effects of 5-fluorouracil (5-FU), metformin (Met), and/or thymoquinone (TQ) single/dual/triple therapies in the HT29, SW480 and SW620 colon cancer (CRC) cell lines. Cell cycle/apoptosis were measured by flow cytometry. The gene and protein expression of apoptosis (PCNA/survivin/BAX/Cytochrome-C/Caspase-3) and cell cycle (CCND1/CCND3/p21/p27) molecules, the PI3K/mTOR/HIF1α oncogenic pathway, and glycolysis regulatory enzymes were measured by quantitative-PCR and Western blot. Markers of oxidative stress were also measured by colorimetric assays. Although all treatments induced anti-cancer effects related to cell cycle arrest and apoptosis, the triple therapy showed the highest pro-apoptotic actions that coincided with the lowest expression of CCND1/CCND3/PCNA/survivin and the maximal increases in p21/p27/BAX/Cytochrome-C/Caspase-3 in all cell lines. The triple therapy also revealed the best suppression of the PI3K/mTOR/HIF1α pathway by increasing its endogenous inhibitors (PTEN/AMPKα) in all cell lines. Moreover, the lowest expression of lactate dehydrogenase and pyruvate dehydrogenase kinase-1 with the highest expression of pyruvate dehydrogenase were seen with the triple therapy, which also showed the highest increases in oxidative stress markers (ROS/RNS/MDA/protein carbonyl groups) alongside the lowest antioxidant levels (GSH/CAT) in all cell lines. In conclusion, this is the first study to reveal enhanced anti-cancer effects for metformin/thymoquinone in CRC that were superior to all monotherapies and the other dual therapies. However, the triple therapy approach showed the best tumoricidal actions related to cell cycle arrest and apoptosis in all cell lines, possibly by enhancing oxidative glycolysis and augmenting oxidative stress through stronger modulation of the PI3K/mTOR/HIF1α oncogenic network.

Metformin: A promising drug for human cancers

Small-molecule chemical drugs are of great significance for tumor-targeted and individualized therapies. However, the development of new small-molecule drugs, from basic experimental research and clinical trials to final application in clinical practice, is a long process that has a high cost. It takes at least 5 years for most drugs to be developed in the laboratory to prove their effectiveness and safety. Compared with the development of new drugs, repurposing traditional non-tumor drugs can be a shortcut. Metformin is a good model for a new use of an old drug. In recent years, the antitumor efficacy of metformin has attracted much attention. Epidemiological data and in vivo, and in vitro experiments have shown that metformin can reduce the incidence of cancer in patients with diabetes and has a strong antagonistic effect on metabolism-related tumors. Recent studies have shown that metformin can induce autophagy in esophageal cancer cells, mainly by inhibiting inflammatory signaling pathways. In recent years, studies have shown that the antitumor functions and mechanisms of metformin are multifaceted. The present study aims to review the application of metformin in tumor prevention and treatment.

In Vivo and In Vitro Enhanced Tumoricidal Effects of Metformin, Active Vitamin D3, and 5-Fluorouracil Triple Therapy against Colon Cancer by Modulating the PI3K/Akt/PTEN/mTOR Network

Simple Summary

Failure of chemotherapy is common during the treatment of colon cancer, and there is a compelling need to develop alternative therapeutic approaches against this common malignancy. Metformin, which is an oral hypoglycaemic agent used for treating diabetes mellitus, and vitamin D have shown promising anticancer activities, and both agents boosted the actions of chemotherapy against colon cancer. This study, therefore, measured the potential beneficial effects of adding metformin and/or active vitamin D to the main cytotoxic drug used for treating colon cancer. The results demonstrate that metformin had superior anticancer effects relative to active vitamin D and ameliorated the effects of chemotherapy in animals and in cells. To the best of our knowledge, this study is also the first to report that triple treatment with the drugs of interest showed the best inhibition of cancer progression, which could provide a better therapeutic strategy against colon cancer.

Abstract

Chemoresistance to 5-fluorouracil (5-FU) is common during colorectal cancer (CRC) treatment. This study measured the chemotherapeutic effects of 5-FU, active vitamin D₃ (VD₃), and/or metformin single/dual/triple regimens as complementary/alternative therapies. Ninety male mice were divided into: negative and positive (PC) controls, and 5-FU, VD₃, Met, 5-FU/VD₃, 5-FU/Met, VD₃/Met, and 5-FU/VD₃/Met groups. Treatments lasted four weeks following CRC induction by azoxymethane. Similar regimens were also applied in the SW480 and SW620 CRC cell lines. The PC mice had abundant tumours, markedly elevated proliferation markers (survivin/CCND1) and PI3K/Akt/mTOR, and reduced p21/PTEN/cytochrome C/caspase-3 and apoptosis. All therapies reduced tumour numbers, with 5-FU/VD₃/Met being the most efficacious regimen. All protocols decreased cell proliferation markers, inhibited PI3K/Akt/mTOR molecules, and increased proapoptotic molecules with an apoptosis index, and 5-FU/VD₃/Met revealed the strongest effects. In vitro, all therapies equally induced G1 phase arrest in SW480 cells, whereas metformin-alone showed maximal SW620 cell numbers in the G0/G1 phase. 5-FU/Met co-therapy also showed the highest apoptotic SW480 cell numbers (13%), whilst 5-FU/VD₃/Met disclosed the lowest viable SW620 cell percentages (81%). Moreover, 5-FU/VD₃/Met revealed maximal inhibitions of cell cycle inducers (CCND1/CCND3), cell survival (BCL2), and the PI3K/Akt/mTOR molecules alongside the highest expression of cell cycle inhibitors (p21/p27), proapoptotic markers (BAX/cytochrome C/caspase-3), and PTEN in both cell lines. In conclusion, metformin monotherapy was superior to VD₃, whereas the 5-FU/Met protocol showed better anticancer effects relative to the other dual therapies. However, the 5-FU/VD₃/Met approach displayed the best in vivo and in vitro tumoricidal effects related to cell cycle arrest and apoptosis, justifiably by enhanced modulations of the PI3K/PTEN/Akt/mTOR pathway.