Abstract
Cisplatin (CDDP) is a highly effective antineoplastic agent, widely used in the treatment of various malignant tumors, including ovary, endometrium, pulmonary, bladder, head and neck, testicular, breast and colorectal cancer. Regarding CDDP-induced toxicity (mainly nephrotoxicity) considerable inter-individual differences have been reported. Several factors must be considered for different degrees of toxicities and outcomes for the same drug, including age, sex, healthy factors, environmental factors, exposure to tobacco smoke, alcohol, clinical factors and genetic factors. Genetic causes can include polymorphisms that affect transporters involved in efflux and influx of CDDP, responsible for the absorption, distribution, metabolization and excretion of the drug. While epigenetic modifications involved in the regulation of these genes and how these would be associated to CDDP-induced toxicity are complementary to this investigation. Interestingly, in the last few years many evidences were found linking microRNA with the development of CDDP-mediated toxicity, particularly with nephrotoxicity in patients treated with this chemotherapeutic drug. Therefore, we can group the causes of CDDP-induced toxicity in genetic and epigenetic factors. The general objective of this study will be identified clinical, genetic and epigenetic factors related to CDDP-induced nephrotoxicity. The specific objectives are: 1) Identify clinical characteristics, single nucleotide polymorphisms and miRNAs associated to CDDP-induced nephrotoxicity in patients with squamous cell carcinoma of head and neck (SCHN); 2) Evaluate the effect of CDDP treatment on DNA methylation and histone modifications in cultured kidney cells; 3) Evaluate the in vitro role of miRNAs related to in vivo CDDP-induced nephrotoxicity. To reach these goals, this study is designed as an observational and prospective study with a consecutive and non-probabilistic sampling strategy. The study is being carried out in three large units: the Clinical Oncology Outpatient Clinic at the Hospital de Clinicas of UNICAMP (Brazil) - a tertiary school hospital, belonging to the public health network and considered as a reference in the Sao Paulo State; the Laboratory of Clinical Pharmacy of the Faculty of Pharmaceutical Sciences of the UNICAMP (Brazil) and the Center of Molecular Biology and Pharmacogenetics of the Faculty of Medicine - "Universidad de La Frontera" (UFRO, Chile). Specific goal 1 (Brazil): Patients with SCHN who start treatment with CCDP and radiotherapy will be included. Nephrotoxicity, expression of urinary miRNAs (hsa-miR-203a-3p; hsa-miR-425-3p; hsa-miR-615-5p) and genetic polymorphisms in renal transporters genes (OTC2 and MATE1) will be evaluated. Specific goal 2 (Chile): HEK-293 cells will be treated with CCDP (10 - 50uM) for 24 hours. Then, the selected CDDP concentration will be used for the following cellular assays. DNA from cultured HEK-293 cells will be isolated and DNA methylation will be quantifying. The histone modification from cells will be determined by EpiQuik" Histone H3 and H4 Modification Multiplex Assay Kits. Specific goal 3 (Brazil/Chile): Differentially expressed miRNAs detected in the in vivo study will be submitted to a target prediction tool combined with IPA bioinformatic analysis, to evaluate the implications of the altered miRNA expression on mRNA expression and to select targets genes potentially related to nephrotoxicity. Once the targets have been selected, the interaction between the miRNA and the 3'UTR region of the selected target will be evaluated by luciferase assay. The comparison of categorical data will be performed using chi-square test. Continuous variables will be first tested to evaluate the value's distribution and then compared between groups by using t test or Mann-Whitney test. Paired data will be analyzed using Friedman test. P<0.05 will be considered statistically significant. (AU)