Uterine fibroids (leiomyomas) are very common benign tumors grown on the smooth muscle layer of the uterus, present in up to 75% of reproductive-age women and causing significant morbidity in a subset of this population. Although the etiology and biology of uterine fibroids are unclear, strong evidence supports that cell proliferation, angiogenesis and fibrosis are involved in their formation and growth. Currently the only cure for uterine fibroids is hysterectomy; the available alternative therapies have limitations. Thus, there is an urgent need for developing a novel strategy for treating this condition. The green tea polyphenol epigallocatechin gallate (EGCG) inhibits the growth of uterine leiomyoma cells in vitro and in vivo, and the use of a green tea extract (containing 45% EGCG) has demonstrated clinical activity without side effects in women with symptomatic uterine fibroids. However, EGCG has a number of shortcomings, including low stability, poor bioavailability, and high metabolic transformations under physiological conditions, presenting challenges for its development as a therapeutic agent. We developed a prodrug of EGCG (Pro-EGCG or 1) which shows increased stability, bioavailability and biological activity in vivo as compared to EGCG. We also synthesized prodrugs of EGCG analogs, compounds 2a and 4a, in order to potentially reduce their susceptibility to methylation/inhibition by catechol-O-methyltransferase. Here, we determined the effect of EGCG, Pro-EGCG, and 2a and 4a on cultured human uterine leiomyoma cells, and found that 2a and 4a have potent antiproliferative, antiangiogenic, and antifibrotic activities. J. Cell. Biochem. 117: 2357-2369, 2016. © 2016 Wiley Periodicals, Inc.

Background: Over recent years, there has been an increasing focus on the repurposing of existing, well-known medications for new, novel usage. One such drug is metformin, typically utilized in the management of diabetes, which demonstrates a positive relationship between its administration and lower cancer morbidity and mortality. Based on this finding, numerous studies and clinical trials have been conducted to examine the potential usage of metformin as an anticancer agent. Objective: This article aims to summarize metformin’s anticancer effects through reviewing its literature and patents, with a focus on its potential to be repurposed for cancer therapy. Methods: Various databases were examined using keywords, ‘Metformin’ and ‘Cancer’. Research articles were collected through the PubMed database, clinical trials were obtained from the Clinical Trials database, and patents were collected through the Google Patents database. Results: Metformin shows antineoplastic activity in various models. These anticancer properties appear to synergize with existing chemotherapeutics, which allows for a reduction in drug dosage without losing potency while minimizing adverse effects. Numerous patents on metformin have been filed which claim various combination therapies, delivery methods, and uses for cancer therapy, displaying an increasing interest in metformin’s anticancer potential. Conclusion: Preclinical studies, along with early phase clinical trials, have examined antitumor properties of metformin on a variety of cancers. Metformin’s anticancer effects are well documented, demonstrating a great promise in improving current cancer therapies. However, there is a significant lack of late phase clinical trials, specifically those involving non-diabetic cancer patients, and therefore further research in this area is required.

Adenosine Monophosphate-Activated Protein Kinase or AMPK is a highly-conserved master-regulator of numerous cellular processes, including: Maintaining cellular-energy homeostasis, modulation of cytoskeletal-dynamics, directing cell growth-rates and influencing cell-death pathways. AMPK has recently emerged as a promising molecular target in cancer therapy. In fact, AMPK deficiencies have been shown to enhance cell growth and proliferation, which is consistent with enhancement of tumorigenesis by AMPK-loss. Conversely, activation of AMPK is associated with tumor growth suppression via inhibition of the Mammalian Target of Rapamycin Complex-1 (mTORC1) or the mTOR signal pathway. The scientific communities’ recognition that AMPK-activating compounds possess an anti-neoplastic effect has contributed to a rush of discoveries and developments in AMPK-activating compounds as potential anticancer-drugs. One such example is the class of compounds known as Biguanides, which include Metformin and Phenformin. The current review will showcase natural compounds and their derivatives that activate the AMPK-complex and signaling pathway. In addition, the biology and history of AMPK-signaling and AMPK-activating compounds will be overviewed, their anticancer-roles and mechanisms-of-actions will be discussed, and potential strategies for the development of novel, selective AMPK-activators with enhanced efficacy and reduced toxicity will be proposed.