Metformin Enhancement of Therapeutic Effects of 5-Fluorouracil and Oxaliplatin in Colon Cancer Cells and Nude Mice

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.

Association of metformin and statin uses with the prognosis of colon cancer: a meta-analysis

BACKGROUND

Metformin and statins are commonly used globally for the treatment of type 2 diabetes mellitus and dyslipidemia, respectively. Recently, multiple novel pathways have been discovered, which may contribute to the treatment of various types of cancer. Several meta-analysis studies have reported that the use of metformin or statins is associated with a lower risk of colon cancer compared to nonusers. In this study, our aim was to perform a meta-analysis and investigate the prognostic roles of these two medications in colon cancer.

METHODS

To identify relevant articles, literature searches were performed in the PubMed and Web of Science databases using a combination of keywords related to metformin, statins and colon cancer prognosis until August 2023. The study utilized STATA 12.0 software (Stata Corporation, College Station, Texas, USA) to compute all the hazard ratios (HRs) and 95% confidence intervals (CIs) regarding the association between metformin or statin uses and prognostic-related outcomes.

RESULTS

Our analysis revealed that the use of metformin was associated with a significantly lower overall mortality of colon cancer (HR = 0.63; 95% CI = 0.51-0.77; I2 = 94.9%; P < 0.001), as well as lower cancer-specific mortality of colon cancer (HR = 0.68; 95% CI = 0.50-0.94; I2 = 91.9%; P < 0.001). Similarly, the use of statins was also associated with a lower overall mortality of colon cancer (HR = 0.68; 95% CI = 0.60-0.78; I2 = 93.8%; P < 0.001), as well as a lower cancer-specific mortality of colon cancer (HR = 0.74; 95% CI = 0.67-0.81; I2 = 82.2%; P < 0.001).

CONCLUSION

Our meta-analysis study suggests that statins and metformin may have potential as adjuvant agents with significant benefits in the prognosis of colon cancer.

Repurposing Metabolic Inhibitors in the Treatment of Colon Adenocarcinoma Patient-Derived Models

The effect of agonists on AMP-activated protein kinase (AMPK), mainly metformin and phenformin, has been appreciated in the treatment of multiple types of tumors. Specifically, the antitumor activity of phenformin has been demonstrated in melanomas containing the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) activating mutation. In this report, we elucidated the synergistic antitumor effects of biguanides with metabolism inhibitors on colon tumors. Phenformin with 2-deoxy-D-glucose (2DG) inhibited tumor cell growth in cancer cell lines, including HT29 cells harboring BRAF- and p53-mutations. Biochemical analyses showed that two chemotherapeutics exerted cooperative effects to reduce tumor growth through cell cycle arrest, apoptosis, and autophagy. The drugs demonstrated activity against phosphorylated ERK and the gain-of-function p53 mutant protein. To demonstrate tumor regressive effects in vivo, we established patient-derived models, including xenograft (PDX) and organoids (PDO). Co-treatment of biguanides with chemotherapeutics efficiently reduced the growth of patient-derived colon models in comparison to treatment with a single agent. These results strongly suggest that significant therapeutic advantages would be achieved by combining AMPK activators such as phenformin and cancer metabolic inhibitors such as 2DG.

Clinicopathological Features and Oncological Outcomes of Early and Late Recurrence in Stage III Colorectal Cancer Patients after Adjuvant Oxaliplatin-Based Therapy

Aims

An adjuvant oxaliplatin-based regimen is the standard of care for patients with stage III colorectal cancer (CRC). Few reports have compared the clinicopathological features and oncological outcomes of such treatment between patients with early (≤1 year) and late recurrence (>1 year).

Methods

Between January 2012 and December 2019, CRC recurred in 128 (24.1%) of 531 patients with consecutive stage III CRC after they received curative resection and an adjuvant oxaliplatin-based regimen. The clinicopathological features and oncological outcomes of the 128 patients were analyzed retrospectively.

Results

The median follow-up period after the first chemotherapy cycle was 35.0 months (range, 7-100.9), and the median recurrence time was 16.1 months. Forty-seven patients (36.7%) had an early recurrence and eighty-one patients (63.3%) had a late recurrence. Compared with patients with late recurrence, those with early recurrence were mostly younger (median: 58 vs. 64 years, p=0.009), had less oxaliplatin-based therapy cycles (median: 8 vs. 12 cycles, p < 0.001), and had a shorter overall survival time (median: 23.3 vs. 39.7 months, p < 0.001). The area under the curve of patient age and chemotherapy cycles for predicting early recurrence was 0.629 and 0.705 (p=0.015 and p < 0.001), respectively. The receiver operating characteristic curve analysis demonstrated that the cutoff level for patient age was 57 years and the number of chemotherapy cycles was 8. A multivariate analysis revealed that patient age ≤57 years and oxaliplatin-based therapy ≤8 cycles were independent risk factors for early recurrence (odds ratio (OR) = 3.049, p=0.022; OR = 4.995, p=0.002). These factors were associated with an approximately 77.8% risk of recurrence within 1 year, compared with the 21.5% risk associated with patient age >57 years and oxaliplatin-based therapy >8 cycles (p = 0.003).

Conclusion

Patients with early recurrence had poorer survival than those with late recurrence. If >8 cycles of oxaliplatin-based therapy can be administered without disease progression, then patients with stage III CRC would have a lower risk of early recurrence.