Metabolic analyses of stress response in a non-cancerous cell line exposed to Cisplatin and a novel PCNA-interacting motif

Abstract

Several proteins involved in DNA-damage repair have been found to interact with the proliferating cell nuclear antigen (PCNA) through a novel PCNA-interacting motif, an amino acid sequence called the AlkB homologue 2 PCNA-interacting motif (APIM). An APIM-containing peptide (ATX-101) has recently been constructed and shown to interfere with the PCNA-interaction of enzymes critical in DNA damage repair, increasing cytostatic-induced apoptosis and inhibiting cell growth in cancer cell lines. A pilot project, which conducted metabolic analysis of stress induced human cell lines, indicated that ATX-101 only had effect on cancer cells, leaving non-cancerous cell lines unaffected. It is of interest to verify the lacking effect of ATX-101 on non-cancerous cell lines alone and in combination with a cytostatic agent. A time series exposure (0, 4, 8 and 24 hours) was conducted on HEK293 cells treated with ATX-101 alone and in combination with the alkylating agent Cisplatin. The cell metabolome were analyzed by mass spectrometry, the variation in metabolite concentration evaluated as an effect of treatment. Both targeted and non-targeted metabolic analysis was conducted. Neither target nor non-target analysis of HEK cells treated with ATX-101 alone or in combination with Cisplatin showed any effect on the cell metabolism, at the applied concentrations. The concentrations used were the same that heavily affected cancerous cells. This study indicate that ATX-101 do not affect normal cell lines, holding a promise of increased efficiency of existing treatment with lesser side effects.