Amplification of chromosome 8q21-qter associated with the acquired paclitaxel resistance of nasopharyngeal carcinoma cells.

objectiveto observe relationship between chromosome imbalance and taxol resistance in nasopharyngeal carcinoma (NPC).

methodsthree taxol-resistant sub-lines were established through repeated exposure of escalating doses of paclitaxel to NPC cell lines (CNE-1, HNE-2 and 5-8F). The change of copy number of chromosomes was investigated by the genome-wide analyses of comparative genomic hybridization (CGH). Gene profiles of both parental and resistant cell lines were determined by cDNA microarray. Cell viability was assayed by colony formation assay.

resultsThe taxol resistant sub-lines (CNE1/Taxol, HNE2/Taxol and 5-8F/Taxol) developed displayed an average 5~8-fold higher IC50 value than their parental cells. The common losses of chromosome 18, 10q11-qter and gains of chromosome 12, 3q21-qter, 5p13-pter and 20q11-qter were observed by CGH in all of 6 NPC cell lines. A common gain region of chromosome 8q21-qter was identified in taxol resistant sub-lines. 15 genes of 762 transcripts on this chromosome region were consistently up-regulated detected by cDNA microarray in three taxol resistant sub-lines, and functionally clustered into various groups, including genes related to vascular formation vascular formation (ANGPT1), apoptosis (MYC, TOP1MT), cell adhesion and cell cycle (PPP1R16A, SDC2, CA2, ANKRD46), gene regulation (HRSP12, ZNF696, SLC39A4, POP1), metabolism (PYCRL). Inhibition of ANGPT1 expression significantly increased the sensitivity of CNE-1/taxol to paclitaxol.

conclusionThe common gain of chromosome 8q21-qter in taxol resistant sublines predicates that potential candidate genes on this region may contribute to taxol resistant phenotype. ANGPT1 may be associated with taxol resistance of NPC cells.