Gemcitabine metabolic pathway genetic polymorphisms and response in patients with non-small cell lung cancer

Abstract

Background and objective Gemcitabine is widely used to treat non-small cell lung cancer (NSCLC). To assess the pharmacogenomic effects of the entire gemcitabine metabolic pathway, we genotyped SNPs within the 17 pathway genes using DNA samples from NSCLC patients treated with gemcitabine to determine the effect of genetic variants within gemcitabine pathway genes on overall survival (OS) of NSCLC patients after treatment of gemcitabine. Methods Eight of the 17 pathway genes were resequenced with DNA samples from Coriell lymphoblastoid cell lines (LCLs) using Sanger sequencing for all exons, exon-intron junctions and 5′-, 3′-UTRs. A total of 107 tag SNPs were selected based on the resequencing data for the 8 genes and on HapMap data for the remaining 9 genes, followed by successful genotyping of 394 NSCLC patient DNA samples. Association of SNPs/haplotypes with OS was performed using the Cox regression model, followed by functional studies performed with LCLs and NSCLC cell lines. Results 5 SNPs in 4 genes (CDA, NT5C2, RRM1, and SLC29A1) showed associations with OS of those NSCLC patients, as well as 9 haplotypes in 4 genes (RRM1, RRM2, SLC28A3, and SLC29A1) with P < 0.05. Genotype imputation using the LCLs was performed for a region of 200kb surrounding those SNPs, followed by association studies with gemcitabine cytotoxicity. Functional studies demonstrated that downregulation of SLC29A1, NT5C2, and RRM1 in NSCLC cell lines altered cell susceptibility to gemcitabine. Conclusion These studies help identify biomarkers to predict gemcitabine response in NSCLC, a step toward the individualized chemotherapy of lung cancer.

Pathway-Based Pharmacogenomics of Gemcitabine Pharmacokinetics in Patients with Solid Tumors

“…The SLC29A1 SNP (rs747199) was associated significantly with dFdU clearance. This SNP has been previously shown to be associated with gemcitabine lethal dose for 50% of cells and overall survival of NSCLC patients receiving gemcitabine [14]. Interestingly for dFdCTP.…”

“…In vitro characterization of rs11191612 showed differential binding of the variant oligo in gel shift assays as well as differential activation in the luciferase assays [13]. This NT5C2 SNP has also been shown to be associated with gemcitabine lethal dose for 50% of cells of lymphoblast cell lines [14].…”

“…The purpose of this study was to comprehensively analyze the nine most important genes implicated in the metabolic pathway of gemcitabine for association of genetic variants with PK end points. One [15], time to progression, overall survival [17,18] Pancreatic cancer: neutropenia [16] CT (n = 16) 3.955 ± 1.696 0.148 ± 0.131 NSCLC: overall survival [14] Solid tumors: gemcitabine plasma clearance [20] CG (n = 15) reporting intracellular dFdCTP levels at multiple time points, especially beyond 4-6 h has not been studied extensively. We evaluated 37 SNPs in nine gemcitabine pathway genes for association with the PK end points such as gemcitabine clearance, dFdU clearance and dFdCTP formation clearance.…”

Using Drosophila melanogaster To Identify Chemotherapy Toxicity Genes

“…RRM2 and RRM2B encode ribonucleotide reductase proteins. Gemcitabine has been shown to inhibit those enzymes, which are required for DNA synthesis (Li et al 2012). The two other QTL are associated with novel candidate genes worthy of additional study.…”

Determination of the enzymatic activity of cytosolic 5′-nucleotidase cN-II in cancer cells: development of a simple analytical method and related cell line models

“…On the other hand, the inhibition of cN-II expression by short hairpin RNA (shRNA) in human astrocytoma cells was associated with decreased enzymatic activity and cell viability in addition to increased caspase 3 activity, indicating a vital role of cN-II in these cancer cells [14]. Finally, the inhibition of cN-II expression by siRNA in human lung cancer A549 cells resulted in a weak sensitization to gemcitabine [15], whereas siRNA-mediated inhibition of cN-II in human breast cancer MDA-MB-231 or pancreatic cancer SU86 cells did not alter sensitivity to gemcitabine or cytarabine [16]. These discrepant results might indicate a specificity of the role of cN-II between tissues, at least for nonhematological cells.…”