Creatine supplementation does not alter proliferation or doxorubicin sensitivity of mammary carcinoma cells

Abstract

Objectives Doxorubicin (DOX) is an effective chemotherapy drug used to treat breast cancer, but its use is limited by detrimental side effects such as cardiotoxicity and skeletal muscle atrophy. Supplementation with creatine has been shown to protect cardiac and skeletal muscle cells from the cytotoxic effects of DOX. One concern with dietary creatine supplementation in cancer patients, however, is the possible protection of cancer cells from therapeutic DOX toxicity. Thus, we investigated the effects of in vitro creatine supplementation on proliferation and survival of DOX-treated MAT-BIII rat mammary carcinoma cells. Methods MATB-III cells were seeded in triplicate at 15,000 cells/well in a 96-well microplate for an eight day incubation in one of six treatments: no treatment, 5 µM DOX, 2 mM creatine, 2 mM creatine + 5 µM DOX, 20 mM creatine, 20 mM creatine + 5 µM DOX. Media and treatments were refreshed every 48 hours. An MTT assay was run on day 8 to assess remaining cell number in each well. The results represent an average from three time separated experiments with differences between treatments identified using a two-way ANOVA (IBM SPSS 27). Significance was at the α=0.05 level. Results As expected, the number of MAT-BIII cells was significantly reduced (P < 0.001) after DOX treatment consistent with impaired proliferation or cytotoxicity. Neither low nor high-dose creatine exposure altered the number of cells or the suppressive effects of DOX as no creatine x DOX interaction was identified (P > 0.05). Conclusion DOX decreased proliferation of MAT-BIII mammary carcinoma cells indicating this cell line is sensitive to the effects of this chemotherapy drug. There was no indication that creatine influenced proliferation or DOX sensitivity of the mammary carcinoma cells. The absence of an effect in this experiment suggests that creatine could be supplemented to alleviate the adverse side effects of DOX treatment in human breast cancer patients. Future research aims to elucidate further the possible interactions between DOX and creatine in cancer cell metabolism.