Magic of a Common Sugar Pill in Cancer: Can Metformin Raise Survival in Pancreatic Cancer Patients?

Synergistic effects of calcium channel blockers and renin-angiotensin inhibitors with gemcitabine-based chemotherapy on the survival of patients with pancreatic cancer

PURPOSE

Pancreatic cancer remains a significant public health challenge, with poor long-term outcomes due to the lack of effective treatment options. Repurposing commonly used clinical drugs, such as ACE inhibitors, ARBs, CCBs, and metformin, may enhance the efficacy of chemotherapy and offer a promising therapeutic strategy for improving patient outcomes.

METHODS

A retrospective analysis of concomitant treatment with ACE-Is, ARBs, CCBs, and metformin alongside gemcitabine chemotherapy in patients with pancreatic cancer was conducted. Treatment responses were evaluated, with overall survival (OS) estimated using the Kaplan-Meier method. Additionally, the Cox proportional hazards model was employed to assess the impact of these specific agents on patient survival.

RESULTS

4628 patients with various stages of pancreatic cancer were identified in the database between 2007 and 2016. The estimated overall survival (OS) in the analyzed group was 6.9 months (95% CI 6.4-7). The use of any of the analyzed drugs was associated with a significant improvement in mOS of 7.5 months (95% CI 6.8-7.8) vs. 6.7 months (95% CI 6.4-7.0) for patients who did not have additional treatment (p < 0.0001). ARBs, ACE-Is, CCBs, and metformin varied in their effectiveness in prolonging mOS among patients. The longest mOS of 8.9 months (95% CI 7.7-11.6) was observed in patients receiving additional therapy with ARBs, while the shortest mOS of 7.7 months (95% CI 6.5-8.9) was achieved by patients receiving metformin. In the adjusted Cox analysis, metformin was associated with a significantly weaker effect on mOS (p = 0.029). A particularly interesting trend in prolonging 5-year survival was demonstrated by ARBs and CCBs with 14.1% (95% CI 9-22%) and 14.8% (95% CI 11.1-19.6%), respectively, compared to patients not taking these drugs, who achieved a 5-year OS of 3.8% (95% CI 3.2-4.4%).

CONCLUSION

Our results demonstrate a significant positive impact of ARBs, ACE inhibitors, and CCBs on survival in patients with pancreatic cancer treated with gemcitabine. The addition of these inexpensive and relatively safe drugs in patients with additional comorbidities may represent a potential therapeutic option in this indication. However, prospective clinical trials to evaluate the optimal patient population and further studies to determine the potential impact of these agents on chemotherapy are necessary.

Antidiabetics, Anthelmintics, Statins, and Beta-Blockers as Co-Adjuvant Drugs in Cancer Therapy

Over the last years, repurposed agents have provided growing evidence of fast implementation in oncology treatment such as certain antimalarial, anthelmintic, antibiotics, anti-inflammatory, antihypertensive, antihyperlipidemic, antidiabetic agents. In this study, the four agents of choice were present in our patients’ daily treatment for nonmalignant-associated pathology and have known, light toxicity profiles. It is quite common for a given patient’s daily administration schedule to include two or three of these drugs for the duration of their treatment. We chose to review the latest literature concerning metformin, employed as a first-line treatment for type 2 diabetes; mebendazole, as an anthelmintic; atorvastatin, as a cholesterol-lowering drug; propranolol, used in cardiovascular diseases as a nonspecific inhibitor of beta-1 and beta-2 adrenergic receptors. At the same time, certain key action mechanisms make them feasible antitumor agents such as for mitochondrial ETC inhibition, activation of the enzyme adenosine monophosphate-activated protein kinase, amelioration of endogenous hyperinsulinemia, inhibition of selective tyrosine kinases (i.e., VEGFR2, TNIK, and BRAF), and mevalonate pathway inhibition. Despite the abundance of results from in vitro and in vivo studies, the only solid data from randomized clinical trials confirm metformin-related oncological benefits for only a small subset of nondiabetic patients with HER2-positive breast cancer and early-stage colorectal cancer. At the same time, clinical studies confirm metformin-related detrimental/lack of an effect for lung, breast, prostate cancer, and glioblastoma. For atorvastatin we see a clinical oncological benefit in patients and head and neck cancer, with a trend towards radioprotection of critical structures, thus supporting the role of atorvastatin as a promising agent for concomitant association with radiotherapy. Propranolol-related increased outcomes were seen in clinical studies in patients with melanoma, breast cancer, and sarcoma.

The Impact of Epithelial-Mesenchymal Transition and Metformin on Pancreatic Cancer Chemoresistance: A Pathway towards Individualized Therapy

Globally, pancreatic ductal adenocarcinoma remains among the most aggressive forms of neoplastic diseases, having a dismal prognostic outcome. Recent findings elucidated that epithelial-mesenchymal transition (EMT) can play an important role in pancreatic tumorigenic processes, as it contributes to the manifestation of malignant proliferative masses, which impede adequate drug delivery. An organized literature search with PubMed, Scopus, Microsoft Academic and the Cochrane library was performed for articles published in English from 2011 to 2021 to review and summarize the latest updates and knowledge on the current understanding of EMT and its implications for tumorigenesis and chemoresistance. Furthermore, in the present paper, we investigate the recent findings on metformin as a possible neoadjuvant chemotherapy agent, which affects EMT progression and potentially provides superior oncological outcomes for PDAC patients. Our main conclusions indicate that selectively suppressing EMT in pancreatic cancer cells has a promising therapeutic utility by selectively targeting the chemotherapy-resistant sub-population of cancer stem cells, inhibiting tumor growth via EMT pathways and thereby improving remission in PDAC patients. Moreover, given that TGF-β1-driven EMT generates the migration of tumor-initiating cells by directly linking the acquisition of abnormal cellular motility with the maintenance of tumor initiating potency, the chemoprevention of TGF-β1-induced EMT may have promising clinical applications in the therapeutic management of PDAC outcomes.