Platinum chemotherapeutic-induced oxidative stress affects the transcriptional response of DNA repair genes in murine mesenchymal stem cells.

Cisplatin and oxaliplatin are among the most extensively used anti-cancer drugs in the treatment of various types of cancer. However, the cytotoxicity associated with these drugs in normal and adult stem cells is a major concern.

Objectives: This study aimed to determine the oxidative stress induced by platinum drugs in murine mesenchymal stem cells (mMSCs).

Methods: mMSCs were cultured and treated with cisplatin and oxaliplatin concentrations (5 μM, 15 μM, and 25 μM/L) for 1, 4, 24, 48, and 72 hours. Morphological changes and viability of cells were observed. Oxidative stress was assessed by the expression of 8-Hydroxy-2'-deoxyguanosine (8-OHdG). Necroptosis was determined by Acridine Orange/Ethidium Bromide (AO/EB) staining. Moreover, mRNA levels of DNA repair genes, particularly genes involved in mismatch repair (MMR), including MLH3, MSH2, MLH1, MSH6, and PMS2, and nucleotide excision repair (NER) pathways, such as ERCC1 were measured using Taq-Man Quantitative Real-Time Polymerase Chain Reaction (TaqMan-qRT-PCR).

Results: The proliferation and morphology of mMSCs were noticeably influenced by cisplatin and oxaliplatin at 25 μM, compared to 5 μM and 15 μM by 72 hours. 8OHdG positive and necroptotic cells were significantly (P < 0.001) high from 24 to 72 hours among 25 μM drug-treated mMSCs. The concentration and temporal oxidative stress generated in mMSCs by cisplatin and oxaliplatin disturbed the expression of DNA repair genes at the mRNA level (P < 0.001). Cisplatin remarkably upregulated the expression of MLH1 and PMS2 (≥ 3.0-fold) at 24 hours, while it downregulated MSH2, MLH1, MSH6, and PMS2 (≤ 0.5-fold) at 72 hours. However, oxaliplatin noticeably caused the upregulation of MLH3 and ERCC1 expression (≥ 3.0-fold) at 24-48 hours, and downregulation of MSH2, MLH1, MSH6, PMS2, and ERCC1 (≤ 0.5-fold) at 72 hours.

Conclusions: This suggests that adult stem cells in tissues and organs are highly vulnerable to platinum drugs during cancer treatment. Additional studies on localized treatments may help to prevent adverse effects on normal cells.