Genome-Wide Functional Analysis of Chemoresistance Genes

Chemotherapy remains a major way in cancer treatment. However, cell resistance to anticancer drugs causes a major obstacle in the treatment. The mechanism of drug resistance is multifactorial because cell responses to anticancer drugs depend on the genetic make-up of target cells and the concentration and frequency of drugs applied to the cells. The strategy in this study will exclude genes whose activity in chemoresistance are post-translationally modified such as phosphorylation. Cell models selected by cisplatin and vincristine, two key anticancer drugs, are used to investigate the candidate resistance genes in the first place. To unravel molecular basis of chemoresistance, genome-wide search of genes that are altered in their expression in resistant cells are extensively approached by cDNA microarray, confirmed by quantitative-PCR (Q-PCR) of the mRNA levels. Functional studies of these candidate genes in drug response in cell-based model system, and under certain circumstances in mouse model will be followed. Selected candidate genes will be overexpressed (gain-of-function) or inhibited by antisense or RNAi (loss-of-function) in cells and the drug sensitivity measured by MTT assay and apoptosis assay (caspase activity protein markers plus sub-G1 induction). So far, there are 18 candidate resistance genes identified by cDNA microarray and confirmed by Q-PCR from cisplatin-selected HeLa cells. Among these genes, NAPA/alphaSNAP, a “protein transport” required protein gene, is characterized and displayed its chemoresistance, preferential to DNA damage. TP53 mutation and antioxidants (TIGAR) were identified to be chemoresistance genes from vincristine-selected multidrug resistance (MDR) lymphoma cells. Preliminary data also suggested HURP, a mitosis-associated gene, which is overexpressed in hepatocellular carcinoma (HCC) cells, as a candidate chemoresistance gene preferential to mitotic damage. The aim of this study is to further investigate the mechanism of these chemoresistance genes. Since the strategy works well, other candidate chemoresistance genes will also be functionally characterized. Sensitizing chemotherapy of this study will provide useful basis to the understanding of and a plausible way to fighting against anticancer resistance.

Project ID:PC9709-0951
External Project ID:NSC97-2320-B182-024-MY3