The temporal relationship between ABCB1 promoter hypomethylation, ABCB1 expression and acquisition of drug resistance
Abstract
Induced expression of the Abcb1 drug transporter often occurs in tumors in response to chemotherapy. The role that epigenetic modifications within the ABCB1 promoter play in Abcb1 expression remains unclear. We selected MCF-7 cells for survival in increasing doses of chemotherapy drugs, and assessed the methylation status of 66 CpG sites within the ABCB1 promoter preceding, accompanying and following the onset of drug resistance. Increased ABCB1 transcript expression coincident with acquisition of resistance to epirubicin or paclitaxel was temporally associated with hypomethylation of the ABCB1 downstream promoter in the absence of gene amplifications or changes in mRNA stability. Treatment of control MCF-7 cells with demethylating and/or acetylating agents increased ABCB1 transcript expression. In addition to broad promoter hypomethylation, dramatic reductions in the methylation of specific CpG sites within the promoter were observed, suggesting that these sites may play a predominant role in transcriptional activation through promoter hypomethylation. Furthermore, our data suggest that allele-specific reductions in ABCB1 promoter methylation regulate promoter usage within paclitaxel-resistant cells. This study provides strong...Continue Reading
References
Citations
Related Concepts
Related Feeds
Antimicrobial Resistance (ASM)
Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections.
Antimicrobial Resistance
Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections.
Cancer Epigenetics and Senescence (Keystone)
Epigenetic changes are present and dysregulated in many cancers, including DNA methylation, non-coding RNA segments and post-translational protein modifications. The epigenetic changes may be involved in regulating senescence in cancer cells. This feed captures the latest research on cancer epigenetics and senescence.
Cancer Epigenetics & Metabolism (Keystone)
Epigenetic changes are present and dysregulated in many cancers, including DNA methylation, non-coding RNA segments and post-translational protein modifications. The epigenetic changes may or may not provide advantages for the cancer cells. This feed focuses on the relationship between cell metabolism, epigenetics and tumor differentiation.