Sequence variants of multi-drug resistance genes, MDR1 and MRP1, and methods for assessment of drug penetration and disposition
Provided are compositions relating to novel MDR1 polymorphisms, including nucleic acids, polypeptides, and recombinant cells, as well as methods for detection of MDR1 polymorphisms in biological samples and elucidation of the influence of MDR1 polymorphisms on MDR1 protein function. Also provided are a rat MRP1 cDNA and protein, stable cell lines expressing the rat MRP1 protein, and methods of assessing drug penetration or disposition in a cell line expressing a recombinant mammalian MRP1 or MDR1 protein, or a homolog thereof.
1. A method for predicting efficacy of a drug in a subject, said subject having a disease or disorder amenable to treatment with the drug and wherein said drug is a substrate of multi-drug resistance 1 (MDR1) gene, the method comprising:
isolating a biological sample from the subject, the biological sample comprising nucleic acids and/or proteins; and
analyzing the biological sample to determine at least one of (a) the nucleotide T at position 1199 of SEQ ID NO:5, and (b) the presence or absence of the S4001 variant of SEQ ID NO:4;
wherein the presence of T at nucleotide position 1199 of SEQ ID NO:5 or the presence of the S4001 variant of SEQ ID NO:4 is indicative of an increased efficacy of the drug in the subject relative to the efficacy of the drug in an individual that is homozygous for a wild-type MDR1 gene.
2. The method of claim 1 , wherein the biological sample comprises nucleic acids and the analyzing step comprises determining the nucleotide present at position 1199 of the multi-drug resistance 1 gene set forth as SEQ ID NO:5.
3. The method of claim 2 , wherein the analyzing step comprises hybridization between said nucleic acid sample and a nucleic acid selected from the group consisting of
(a) a nucleic acid comprising about 10 to about 100 contiguous nucleotides of a G1199T variant of the nucleotide sequence set forth in SEQ ID NO:5, said nucleic acid comprising at least one of the nucleotide at position 1199 and a base adjacent thereto; and
(b) a nucleic acid that is fully complementary to the nucleic acid of (a).
4. The method of claim 2 , further comprising determining the genotype at nucleotide position 1199 of the multi-drug resistance 1 gene set forth as SEQ ID NO:5.
5. The method of claim 1 , wherein the drug is a cytotoxic chemotherapeutic agent.
6. The method of claim 5 , wherein the chemotherapeutic agent is selected from the group consisting of doxorubicin, paclitaxol, vinblastine, and vincristine.