Pharmacogenomic Profiling of Cisplatin-Resistant and -Sensitive Human Osteosarcoma Cell Lines by Multimodal Targeted Next Generation Sequencing

Cisplatin (CDDP) is a drug for high-grade osteosarcoma (HGOS) treatment. Several germline pharmacogenetic studies have revealed associations between single nucleotide polymorphisms (SNPs) and CDDP-based therapy response or CDDP-related toxicity in patients with HGOS. Whether these variants could play a biological role in HGOS cells has not been studied so far. The aim of this study was to explore 28 SNPs of 14 genes in 6 CDDP-resistant and 12 drug-sensitive human HGOS cell lines. An innovative multimodal targeted next generation sequencing (mmNGS) approach with custom primers designed for the most commonly reported SNPs of genes belonging to DNA repair, CDDP transport or detoxification, or associated with CDPP-related toxicity was applied. The mmNGS approach was validated by TaqMan genotyping assays and emerged to be an innovative, reliable tool to detect genetic polymorphisms at both the DNA and RNA level. Allele changes in three SNPs (ERCC2 rs13181 and rs1799793, ERCC1 rs11615) were identified on both DNA and RNA derived libraries in association with CDDP resistance. A change of the GSTP1 rs1695 polymorphism from AA to AG genotype was observed in the RNA of all six CDDP-resistant variants. These SNPs emerged to be causally associated with CDDP resistance in HGOS cells.