Description
The SKOV-3 and Caov-3 ovarian cancer cell lines where seeded onto the 100mm cell culture plate for overnight. The cells were then incubated with IL-6 (30ng/ml) alone for one hour or pre-treated with siltuximab for four hours and then treated with IL-6 for one hour. Total RNA was collected from these cells using TRIzol Reagent (GIBCO Grand Island, NY) according to the manufacturers instructions. To account for and eliminate biologic noise, RNA was isolated from three distinct flasks of each cell line and pooled together. RNA quality was determined via ethidium bromide staining following agarose/formaldehyde gel electrophoresis. Total RNA was processed and hybridized to Affymetrix Genechip HG-U95Av2 arrays (Affymetrix, Santa Clara, CA) by the Gene Array Technology Center at Harvard Medical School (http://genome.med.harvard.edu). Affymetrix Gene Chip U133 Plus 2.0 in the first and most comprehensive whole human genome expression array. This array completes coverage of the whole human Genome with over 47,000 transcripts. The expression level of each mRNA is quantified by measuring its hybridization to these 23-mers in comparison to its hybridization to a one-base mismatch oligonucleotide. GeneSifter was used to analyze the microarray data (http://www.genesifter.net/web/). Fold change in expression between sensitive and resistant cell lines was evaluated using the Mann-Whitney test. A tenfold or greater change in intensity combined with a Mann-Whitney associated P value less than 0.05 was used as the criterion for inclusion in our filtered data set.