Antidiabetic drug metformin mitigates ovarian cancer SKOV3 cell growth by triggering G2/M cell cycle arrest and inhibition of m-TOR/PI3K/Akt signaling pathway
Authors: H He
Y-L Fu
X-W Wang
Q-H Zhang
Journal: European Review for Medical and Pharmacological Sciences (2017)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Metformin; Anticancer activity; Ovarian cancer; SKOV3 cells; IC50
Affiliations: Department of Obstetrics and Gynecology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. .

Abstract:  Objective: Metformin is one of most extensively prescribed oral hypoglycemic drug and has received increased attention in recent times for its antitumorigenic potential. Many possible mechanisms have been proposed for the ability of metformin to overturn cancer growth in vitro and in vivo. The objective of the present study was to evaluate the anticancer activity of metformin against ovarian SKOV3 cancer cells. Materials and methods: Anticancer activity and IC50 value of metformin were determined by MTT assay. Reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and effect on cycle were determined by flow cytometry. Protein expression was estimated by Western blotting. Results: Results indicated that metformin exhibited an IC50 of 20 mM against ovarian SKOV3 cancer cell line. Metformin also caused DNA damage in SKOV3 cells and also prompted ROS-mediated alterations in mitochondrial membrane potential. Nonetheless, it triggered cell cycle arrest of SKOV3 at G2/M checkpoint. The activation of the PI3K/AKT/mTOR pathway plays a vital role in ovarian cancer tumorigenesis, progression and chemotherapy resistance. The results showed that metformin significantly inhibited the expression levels of key proteins of PI3K/Akt/mTOR signaling pathway. Conclusions: We propose that metformin exhibits anticancer activity in SKOV3 cells and may prove beneficial in the management of ovarian cancers. 

Retracted: No

PubPeer comments:
 Fig 6.  Images showing in-vitro cytotoxicity assay on (L-929) fibroblast cells representing (a) positive control (b) negative control (c) test sample. ![file] The panels also appear as Fig 14 of [Jain et al (2020)] , Fig 7 of [Markam Pajpai (2020)] , Fig 8 of [Sonker et al (2018)] , and Fig 13 of [Kiro et al (2017)] . The  test samples purportedly show the growth of fibroblasts on different materials in each case. ![file] , 
 #1 In a series of papers, the lead author used an L-929 assay to test that various nanotech materials and drug-delivery vehicles were not cytotoxic. Here, L-929 fibroblasts were cultured in the presence of or on a substrate of the material in question, then examined under a microscope, assessing any signs of damaged morphology on an ordered-categorical scale of 0 to 4. The ends of the scale were calibrated with negative and positive controls (no extreme cytotoxicity). Fig 14 of u201cPredictions of Drugu2013Protein Interactions and Study of Magnetically Assisted Release Dynamics of 5-Fluorouracil from Soya Protein-Coated Iron Oxide Coreu2013Shell Nanoparticlesu201d, [Jain et al (2020)] . Fig 7 of u201cFunctionalization of ginger derived nanoparticles with chitosan to design drug delivery system for controlled release of 5-amino salicylic acid (5-ASA) in treatment of inflammatory bowel diseases: An in vitro studyu201d, [Markam Bajpai (2020)] . Fig 8 of u201cMagnetically responsive release of 5-FU from superparamagnetic egg albumin coated iron oxide core-shell nanoparticlesu201d, [Sonker et al (2018)] . Fig 8 of u201cSilver hydroxyapatite reinforced poly(vinyl alcohol)u2014starch cryogel nanocomposites and study of biodegradation, compressive strength and antibacterial activityu201d, [Bagri et al (2018)] . Fig 13 of u201cDesigning of silk and ZnO based antibacterial and noncytotoxic bionanocomposite films and study of their mechanical and UV absorption behavioru201d, [Kiro et al (2017)] . Fig 6 of u201cPoly (acrylic acid) grafted gelatin nanocarriers as swelling controlled drug delivery system for optimized release of paclitaxel from modified gelatinu201d, [Pal et al (2018)] . Fig 5 of  Easy fabrication and characterization of gelatin nanocarriers and in vitro investigation of swelling controlled release dynamics of paclitaxel , [Pal et al (2018)] . Fig 4 of u201cInvestigation of In Vitro Release of Cisplatin from Electrostatically Crosslinked Chitosan-Alginate Nanoparticlesu201d, [Maan et al (2016)] . Fig 8 of u201cAn In Vitro Experimental Approach to Study Magnetically Targeted Release of Methotrexate From Superparamagnetic Starch Nanocarriersu201d, [Likhitkar Bajpai (2014)] . Fig 8 of u201cCumulative release of cefotaxim from interpenetrating networks of poly(vinyl alcohol-g-acrylamide) and chitosan-g-polyacrylamide chainsu201d, [Prabhakar et al (2014)] . Fig 5 of u201cFabrication of Interpenetrating Networks of Poly (vinyl alcohol-g-acrylamide) and Chitosan-g-polyacrylamide Chains and Evaluation of Water Sorption, Blood Compatibility and Cytotoxicity Behaviorsu201d, [Prabhakar et al (2012)] . ![file] Several papers explain that u201cFor negative control, the sample was prepared by incubating a 1.25 cm2 polyethylene disc with 1 mL of culture medium with serum at 37 u00b11 C; a positive control was prepared by diluting phenol stock solution (13 mg ml) with culture medium with serumu201d. In other cases, u201cIn these experiments USP-grade low density polyethylene RS was used as the negative control and tin stabilized polyvinyl chloride as positive controlu201d... or u201cIn these experiments USPgrade low density polyethylene RS was used as the negative control and tin stabilized polyvinyl chloride as positive controlu201d... or u201cThe positive control test was done by preparing the stock solution of phenol (13 mg mL) using culture medium containing serum. For negative control 1.25 cm2 polyethylene disc was incubated in 1 mL culture medium containing serumu201d... or u201cTest sample (cryogel nanocomposite), negative (high density polyethylene) and positive control (stabilized PVA disk)u201d or the controls were not described. Nevertheless, the same images illustrate the Negative control in all of these papers, while another two images illustrate the Positive control, so evidently since the controls were performed once they did not need to be repeated. I am not sure what they are controlling for but I donu2019t make the rules. Of more interest is the use of the same **sample** image, across considerable variation in materials. ,