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Synergistic inhibition of tumor cell proliferation by metformin and mito-metformin in the presence of iron chelators. Oncotarget 2019 May 28;10(37):3518-3532

Date

06/14/2019

Pubmed ID

31191823

Pubmed Central ID

PMC6544408

DOI

10.18632/oncotarget.26943

Scopus ID

2-s2.0-85089087803   8 Citations

Abstract

We demonstrate that combined treatment with metformin (Met) or its mitochondria-targeted analog, mito-metformin (Mito-Met), and various iron chelators synergistically inhibits proliferation of pancreatic and triple-negative breast cancer cells. Previously, we reported that Met (at millimolar levels) and Mito-Met (at micromolar levels) inhibited pancreatic cancer cell proliferation. Inhibition of mitochondrial complex I and mitochondrial oxidative phosphorylation (OXPHOS) through stimulation of mitochondrial redox signaling was proposed as a key mechanism for decreased cancer cell proliferation. Because of its poor bioavailability, the use of Met as a "stand-alone" antitumor drug has been questioned. Iron chelators such as deferasirox (DFX) and dexrazoxane (DXR) exhibit antiproliferative effects in cancer cells. The potency of Met and Mito-Met was synergistically enhanced in the presence of iron chelators, DFX, N,N'-bis(2-hydroxyphenyl)ethylendiamine-N,N'-diacetic acid (HBED), and deferoxamine (DFO). Met, DXR (also ICRF-187), and DFO are FDA-approved drugs for treating diabetes, decreasing the incidence and severity of cardiotoxicity following chemotherapy, and mitigating iron toxicity, respectively. Thus, the synergistic antiproliferative effects of Met and Met analogs and iron chelators may have significant clinical relevance in cancer treatment. These findings may have implications in other OXPHOS-mediated cancer therapies.

Author List

Cheng G, Zielonka J, Hardy M, Ouari O, Chitambar CR, Dwinell MB, Kalyanaraman B

Authors

Gang Cheng PhD Assistant Professor in the Biophysics department at Medical College of Wisconsin
Michael B. Dwinell PhD Director, Professor in the Microbiology and Immunology department at Medical College of Wisconsin
Micael Joel Hardy PhD Visiting Assistant Professor in the Biophysics department at Medical College of Wisconsin
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin
Jacek M. Zielonka PhD Assistant Professor in the Biophysics department at Medical College of Wisconsin