Association of changes in expression of HDAC and SIRT genes after drug treatment with cancer cell line sensitivity to kinase inhibitors

Abstract

Histone deacetylases (HDACs) and sirtuins (SIRTs) are important epigenetic regulators of cancer pathways. There is a limited understanding of how transcriptional regulation of their genes is affected by chemotherapeutic agents, and how such transcriptional changes affect tumour sensitivity to drug treatment. We investigated the concerted transcriptional response of HDAC and SIRT genes to 15 approved antitumor agents in the NCI-60 cancer cell line panel. Antitumor agents with diverse mechanisms of action induced upregulation or downregulation of multiple HDAC and SIRT genes. HDAC5 was upregulated by dasatinib and erlotinib in the majority of the cell lines. Tumour cell line sensitivity to kinase inhibitors was associated with upregulation of HDAC5, HDAC1, and several SIRT genes. We confirmed changes in HDAC and SIRT expression in independent datasets. We also experimentally validated the upregulation of HDAC5 mRNA and protein expression by dasatinib in the highly sensitive IGROV1 cell line. HDAC5 was not upregulated in the UACC-257 cell line resistant to dasatinib. The effects of cancer drug treatment on expression of HDAC and SIRT genes may influence chemosensitivity and may need to be considered during chemotherapy.

Keywords: HDAC5; Histone deacetylase; chemosensitivity; dasatinib; sirtuin.

Figure 1.

Examples of changes in expression of HDAC genes in response to treatment with erlotinib and dasatinib. Shown are transcriptional changes (log₂FC) at 2 (left panel), 6 (middle panel), and 24 hr (right panel) after treatment. Horizontal right bars indicate elevated gene expression, whereas left bars show decreased expression relative to the untreated cell lines. As summarized in Table 1, concerted upregulation at 24 hr (shown on the right most panels) was observed for HDAC5 after treatment with (a) the high (2,000 nM) and (b) the low (100 nM) concentrations of dasatinib and (c) the high (10,000 nM) concentration of erlotinib. (d) expression changes of HDAC2 after treatment with the high concentration of dasatinib showed concerted downregulation at 6 hr (middle panel) and 24 hr (right panel). Colors represent cancer categories. The scale on the bottom represents log₂ difference between expression values of treated and untreated cell lines. The scale for each microarray experiment is specific to that experiment.

Figure 2.

Experimental validation of transcriptional and protein levels of HDAC5 in the IGROV1, MDA-MB-231, and UACC-257 cell lines after treatment with 2000 nM of dasatinib. (a) Transcriptional changes in mRNA levels using RT-PCR. Results of two independent probes to HDAC5 are normalized to GAPDH. (b) Changes in protein levels using Western blots. Protein results are first normalized to GAPDH and then values divided by normalized untreated cells. Full blots are shown.