BOA20
A transcriptomic and genomic investigation into taxane resistant breast cancer
Juliet Kenicer1, Maryou Lambros2, Vicky Sabine1, Jorge Reis Filho2, John Bartlett1
1University of Edinburgh, UK, 2The Institute of Cancer Research, London, UK
The taxanes are powerful chemotherapeutics used to treat breast cancer. Taxane resistance has become increasingly more prevalent in the clinic; This problem is exacerbated by a lack of understanding of mechanisms underlying taxane resistance.
Three resistant breast cancer cell-line panels: paclitaxel resistant (PACR) MDA-MB-231s/ZR75-1s and docetaxel resistant (DOCR) ZR75-1s were derived by incrementally increasing taxane dose over time. MDA-MB-231: native, 5nM, 25nM and 100nM PACR cells, ZR75-1: native, and 5nM, 25nM, and 50nM PACR and ZR75-1: native, and 5nM, 25nM and 50nM DOCR cells were analysed. RNA from native and PACR MDA-MB-231 cell lines was analysed on the Illumina® human ref.8V2 chip. Data was analysed using IlluminaGui. For aCGH, DNA was extracted from MDA-MB-231 PACR, ZR75-1 PACR and DOCR and respective parental lines, labelled and hybridised to a BAC microarray. Each cell-line was tested against reference samples of DNA from pooled female blood. Taxane resistant cells were tested against their parental cell line.
Illumina data shows that resistance to increasing doses of paclitaxel is associated with sequential increases in mRNA dysregulation in MDA-MB-231 cells. A group of genes identified that were common to multiple paclitaxel resistant group included candidates such as YY1, AURKA and CCND2. aCGH has identified several interesting areas of loss, gain and amplification in the taxane resistant cell- lines, including chromosome loss of 6p and gain of 2p.. Illumina and aCGH data has been correlated with one another using specially designed algorithms.
The illumina experiment will be repeated including ZR75-1 PACR and DOCR as well as MDA-MB-231 PACR cells. Genes upregulated in taxane resistant clones identified in the illumina experiment and supported by the aCGH will be knocked down using shRNA to see if sensitivity is restored. Proteins expressed by these genes will be targeted with inhibitors to test potential candidates for reversing taxane resistance.
