Effect of ABCB1 and ABCC3 Polymorphisms on Osteosarcoma Survival after Chemotherapy: A Pharmacogenetic Study

Background: Standard treatment for osteosarcoma patients consists of a combination of cisplatin, adriamycin, and methotrexate before surgical resection of the primary tumour, followed by postoperative chemotherapy including vincristine and cyclophosphamide. Unfortunately, many patients still relapse or suffer adverse events. We examined whether common germline polymorphisms in chemotherapeutic transporter and metabolic pathway genes of the drugs used in standard osteosarcoma treatment may predict treatment response. Methodology/Principal Findings: In this study we screened 102 osteosarcoma patients for 346 Single Nucleotide Polymorphisms (SNPs) and 2 Copy Number Variants (CNVs) in 24 genes involved in the metabolism or transport of cisplatin, adriamycin, methotrexate, vincristine, and cyclophosphamide. We studied the association of the genotypes with tumour response and overall survival. We found that four SNPs in two ATP-binding cassette genes were significantly associated with overall survival: rs4148416 in ABCC3 (per-allele HR = 8.14, 95%CI = 2.73-20.2, p-value = 5.1×10 -5), and three SNPs in ABCB1, rs4148737 (per-allele HR = 3.66, 95%CI = 1.85-6.11, p-value = 6.9×10 -5), rs1128503 and rs10276036 (r 2 = 1, per-allele HR = 0.24, 95%CI = 0.11-0.47 p-value = 7.9×10 -5). Associations with these SNPs remained statistically significant after correction for multiple testing (all corrected p-values [permutation test] ≤0.03). Conclusions: Our findings suggest that these polymorphisms may affect osteosarcoma treatment efficacy. If these associations are independently validated, these variants could be used as genetic predictors of clinical outcome in the treatment of osteosarcoma, helping in the design of individualized therapyThis work was supported by the AECC (Asociación Española contra el Cáncer), FIS (Fondo de Investigación Sanitaria-Instituto de Salud Carlos III) and the ‘‘Inocente Inocente’’ Foundatio

Classification of Inhibitors of Hepatic Organic Anion Transporting Polypeptides (OATPs): Influence of Protein Expression on Drug–Drug Interactions

ABSTRACT: The hepatic organic anion transporting poly-peptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug−drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors

Contrasting effects of diclofenac and ibuprofen on active imatinib uptake into leukaemic cells

BACKGROUND: The human organic cation transporter-1 (OCT-1) is the primary active protein for imatinib uptake into target BCR-ABL-positive cells. Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used by chronic myeloid leukaemia (CML) patients on imatinib to manage musculoskeletal complaints. METHODS: Here we investigated the impact of NSAIDs on functional activity of the OCT-1 (OCT-1 activity; OA) in CML cells. RESULTS: Although ten of twelve NSAIDs tested had no significant impact on OA (P>0.05), we observed increased OA (27% increase in K562; 22% increase in KU812 cells, P<0.05) and reduced IC50(imatinib) when treated with diclofenac. Co-incubation with imatinib and diclofenac resulted in a significantly lower viable cell number compared with imatinib alone. In contrast, ibuprofen led to a significant decrease in OA, an increase in IC50(imatinib) and thus reduced the cytotoxicity of imatinib. In primary CML samples, diclofenac significantly increased OA, particularly in patients with low OA (<4 ng per 200 000 cells), and significantly decreased IC50(imatinib). Ibuprofen induced significant decreases in OA in CML samples and healthy donors. CONCLUSION: On the basis of the expected impact of these two drugs on OA, ibuprofen should be avoided in combination with imatinib. Further studies are warranted regarding the potential benefit of diclofenac to improve OA in a clinical setting.J. Wang, T.P. Hughes, C.H. Kok, V.A. Saunders, A. Frede, K. Groot-Obbink, M. Osborn, A.A. Somogyi, R.J. D’Andrea and D.L. Whit

Inorganic mercury in mammary cells: viability, metal uptake but efflux?

The viability, cellular uptake and subcellular distribution of heavy metal Hg, were determined in human mammary cell lines (MCF-7, MDA-MB-231 and MCF-10A). It was observed that Hg had the capacity of being excluded from the cells with a different type of possible transporters. MCF-7 cells showed the lowest viability, while the other two cell lines were much more resistant to Hg treatments. The intracellular concentration of Hg was higher at lower exposure times in MCF-10A cells and MCF-7 cells; but as the time was increased only MDA-MB-231 showed the capacity to continue introducing the metal. In MCF-7 and MCF-10A cells the subcellular distribution of Hg was higher in cytosolic fraction than nucleus and membrane, but MDA-MB-231 showed membrane and nucleus fraction as the enriched one. The analysis of RNA-seq about the genes or family of genes that encode proteins which are related to cytotoxicity of Hg evidenced that MCF-10A cells and MCF-7 cells could have an active transport to efflux the metal. On the contrary, in MDA-MB-231 no genes that could encode active transporters have been found.Fil: Ávila Maniero, Mariángeles. Universidad "Juan Agustín Maza"; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Guerrero Gimenez, Martin Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Fanelli, Mariel Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentin