Metformin Caused Radiosensitivity of Breast Cancer Cells through the Expression Modulation of miR-21-5p/SESN1axis

Metformin: From Diabetes to Cancer-Unveiling Molecular Mechanisms and Therapeutic Strategies

Metformin, a widely used anti-diabetic drug, has garnered attention for its potential in cancer management, particularly in breast and colorectal cancer. It is established that metformin reduces mitochondrial respiration, but its specific molecular targets within mitochondria vary. Proposed mechanisms include inhibiting mitochondrial respiratory chain Complex I and/or Complex IV, and mitochondrial glycerophosphate dehydrogenase, among others. These actions lead to cellular energy deficits, redox state changes, and several molecular changes that reduce hyperglycemia in type 2 diabetic patients. Clinical evidence supports metformin's role in cancer prevention in type 2 diabetes mellitus patients. Moreover, in these patients with breast and colorectal cancer, metformin consumption leads to an improvement in survival outcomes and prognosis. The synergistic effects of metformin with chemotherapy and immunotherapy highlights its potential as an adjunctive therapy for breast and colorectal cancer. However, nuanced findings underscore the need for further research and stratification by molecular subtype, particularly for breast cancer. This comprehensive review integrates metformin-related findings from epidemiological, clinical, and preclinical studies in breast and colorectal cancer. Here, we discuss current research addressed to define metformin's bioavailability and efficacy, exploring novel metformin-based compounds and drug delivery systems, including derivatives targeting mitochondria, combination therapies, and novel nanoformulations, showing enhanced anticancer effects.

[How could physical activity decrease the risk of breast cancer development and recurrence?]

OBJECTIVES

Breast cancer is the most frequent and deadly cancer among women. In France, 50% of adults are currently overweight, mostly as a result of a sedentary lifestyle. Numerous studies have highlighted overweight, obesity and lack of physical activity as risk factors for the occurrence and prognosis of cancers, particularly breast cancer. The aim of this study was to understand the extent to which physical activity can improve this prognosis, and what the pathophysiology is.

METHODS

The Senology Commission of the Collège national des gynécologues et obstétriciens français (CNGOF) based its responses on an analysis of the international literature using a Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) methodology conducted on the PubMed database between 1994 and 2023.

RESULTS

A total of 70 articles were selected, demonstrating the role of regular physical activity in reducing the risk of breast cancer occurrence and recurrence. This role in controlling carcinogenesis is mediated by metabolic factors such as leptin, adiponectin and insulin, sex hormones and inflammation. The signaling pathways deregulated by these molecules are known carcinogenic pathways which could be used as therapeutic targets adapted to this population, without replacing the essential hygienic-dietary recommendations.

CONCLUSION

Physical activity has a protective effect on breast cancer risk and prognosis. We must therefore continue to raise awareness in the general population and promote physical activity as a means of primary, secondary, and tertiary prevention.