ABCC4 functional SNP in the 3′ splice acceptor site of exon 8 (G912T) is associated with unfavorable clinical outcome in children with acute lymphoblastic leukemia

Abstract

Objectives: ATP-binding cassette subfamily C member 4 (ABCC4) encoding MRP4 protein is involved in pediatric acute lymphoblastic leukemia (ALL) drug resistance. The nonsynonymous single nucleotide polymorphism (SNP) rs2274407 (G912T; K304N) is located in the 3′ splice acceptor site of exon 8 of ABCC4 pre-mRNA. The aim of this study was to investigate the prognostic value of rs2274407 in childhood ALL and its possible functional effect on MRP4. Methods: ABCC4 G912T SNP was genotyped in 145 Iranian Philadelphia-negative (Ph−) children with ALL using modified tetra-primer ARMS PCR and evaluated for possible association with 3-year disease-free survival (3DFS). In addition, functional impact of rs2274407 on the MRP4 activity and possible post-transcriptional modifications were bioinformatically and experimentally studied. Results: ABCC4 912T allele carriers (G/T and T/T genotypes) are associated with worse 3DFS in Pre-B cell ALL [P = 0.00019, OR (95% CI) = 13.17 (2.55–68.11)]. In addition, computational studies showed that K304N alteration has no impact on the MRP4 activity. However, it may disrupt the normal splicing process of ABCC4 pre-mRNA. Conclusions: To date, this is the first study that shows the potential functional impact of rs2274407 SNP on the aberrant splicing of ABCC4 mRNA. We also demonstrated a robust association between G912T and pediatric ALL negative outcome, which may be explained by the novel computational studies performed in this study. © 2017, Springer-Verlag Berlin Heidelberg.