These enzymes [8, 9] initiate an antioxidant response, which can be beneficial for cancer prevention [13]. However, the Nrf2-ARE pathway has recently been implicated in chemoresistance and the feasibility of Nrf2 inhibition as a strategy for sensitizing cells to chemotherapeutics was demonstrated [13–15]. HMOX1 upregulation has been identified in the adaphostin response in adherent cell lines, but not in hematopoietic cell line models, and it appears that adaphostin
activates a different oxidative stress response in solid tumor models than in leukemia models. Thus, we have selleck kinase inhibitor investigated the mechanism behind HMOX1 induction in the adaphostin-sensitive lung tumor cell line NCI-H522, and demonstrated an enhancement of adaphostin toxicity following inhibition of Nrf2 nuclear translocation with the PI3K inhibitor wortmannin. Methods Drugs and Cell Culture Adaphostin (NSC 680410) and wortmannin (NSC 221019) were obtained from the repository of the National Cancer Institute’s Developmental Therapeutics Program (Rockville, Maryland). Desferrioxamine (DFX) and N-acetyl-cysteine (NAC) were purchased from Sigma® (St. Louis, Missouri). NCI-H522, and the leukemia cell lines, (Jurkat, HL60 and K562) were obtained
from the NCI-60 Human Tumor Cell Line Screen (National Cancer Institute-Frederick, Maryland). Transcriptional Profiling: Microarray Technology Human OperonV2, 20K arrays, BMN 673 in vitro (National Cancer Institute microarray facility/Advanced Technology Center, Gaithersburg, Maryland) were utilized according to published protocols http://madb.nci.nih.gov/. Using competitive hybridization
of treated versus untreated samples chemically coupled PAK5 to a Cy™3 or Cy™5 fluorescently labeled dye (Amersham Biosciences, Little Chalfont Buckinghamshire, England) and fluorescence was read on a GenePix 4100A microarray scanner purchased from Axon Instruments (Union City, California). Data was analyzed using the Axon GenePix Pro 4.1 software and data and image files were then uploaded to the National Cancer Institute/Cancer Center for Research Microarray Center mAdB Gateway for analysis and comparison of multiple arrays. Real Time RT-PCR Five hundred nanograms of total RNA for each sample was reverse transcribed using the GeneAmp® PCR System 9700 and TaqMan® Reverse Transcription Reagents kit. Quantitative real time PCR reactions were conducted and EPZ015938 cell line measured using the ABI Prism™ 7700 Sequence Detection System and TaqMan® chemistries using published primers. Samples were tested in triplicate wells for the genes of interest and for the endogenous control, 18 S.