Structures of oxaliplatin‐oligonucleotide adducts from DNA

Abstract

Oxaliplatin, [(1R,2R)-cyclohexane-1,2-diamine](ethanedioato-O,O')platinum(II) shows a great efficiency against colorectal cancer. Although the mode of action of oxaliplatin is not yet understood, it is commonly accepted that binding of oxaliplatin to DNA prevents DNA synthesis and alters protein to DNA binding. In order to elucidate the modified DNA-protein interaction and thus to understand the mechanisms leading to cellular misinterpretation of DNA information and apoptosis, we have identified the preferential binding sites and the dynamics of the oxaliplatin-DNA intrastrand and interstrand adducts at the oligomer level using high-performance liquid chromatography/electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS) and HPLC/inductively coupled plasma-MS for quantitative studies. We used a combination of benzonase, alkaline phosphatase and Nuclease S1 for digestion. This digestion procedure allows the study of platinated oligomeric nucleotides and more complex interstrand adducts. The digestion products were mostly chromatographically separated and characterized using HPLC/ESI-ion trap MS/MS experiments. We could show that the adducts to guanine and adenine are quite dynamic; that is, the ratios are changing for several days. In addition, the resulting adducts provide evidence for the action of the digesting enzymes and indicate that the adduct spectrum at the oligomeric level is different to that at the commonly studies dinucleotide level.

Neural precursor cell expressed, developmentally downregulated 8-activating enzyme inhibitor MLN4924 sensitizes colorectal cancer cells to oxaliplatin by inducing DNA damage, G2 cell cycle arrest and apoptosis

“…It has previously been reported that oxaliplatin is involved in DNA damage by inducing DNA cross-links and activating the DDR (4,5). The present study demonstrated that MLN4924 and oxaliplatin treatment induced increased protein expression levels of p-H2A and p-CHK2 compared with single agent treatment in CRC cells.…”

“…Oxaliplatin (Sigma-Aldrich; Merck Millipore, Darmstadt, Germany) was dissolved in sterile water and stored at -20˚C. SW620 and HCT116 were seeded into 24-well plates at a density of 1x10 4 Western blotting. Cells were lysed with radioimmunoprecipitation assay lysis buffer (Beyotime Institute of Biotechnology, Haimen, China) containing phenylmethylsulfonyl fluoride (Beyotime Institute of Biotechnology), and lysates were centrifuged at 13,500 x g for 5 min at 4˚C.…”

“…Oxaliplatin is a third-generation platinum analog that may disrupt DNA replication and transcription, leading to DNA damage and cell apoptosis (4,5). Oxaliplatin-based chemotherapy is a primary treatment for patients with metastatic CRC; however, its efficacy is limited.…”

Molecules and elements for quantitative bioanalysis: The allure of using electrospray, MALDI, and ICP mass spectrometry side‐by‐side

“…Again the structure analysis of the modified oligonucleotides was based on ESI/MSMS data, but quantitative data were only accessible via LC/ICP‐MS . In this study we used phosphorus again to quantify DNA adducts in order to show DNA repair of cross links (Figure )…”

miR-122 Targets X-Linked Inhibitor of Apoptosis Protein to Sensitize Oxaliplatin-Resistant Colorectal Cancer Cells to Oxaliplatin-Mediated Cytotoxicity

“…Oxaliplatin induces apoptosis in CRC cells by damaging cellular DNA through the formation of intrastrand guanine-guanine and guanineadenine DNA links [12,13]. However, under the long-term use of oxaliplatin, cancer cells usually change their gene expression profile to acquire drug resistance against oxaliplatininduced apoptosis [14][15][16].…”