The HDAC inhibitor panobinostat acts as a sensitizer for erlotinib activity in EGFR mutated and wildtype NSCLC cells

ABSTRACT: The receptor tyrosine kinase (RTK) EGFR is overexpressed and mutated in NSCLC. These mutations can be targeted by RTK inhibitors (TKIs), such as erlotinib. Chromatin-modifying agents offer a novel therapy approach by sensitizing tumor cells to TKIs. The NSCLC cell lines HCC827 (EGFR mutant, adenocarcinoma), A549 (EGFR wt, adenocarcinoma) and NCI-H460 (EGFR wt, large cell carcinoma) were analyzed by SNP6.0 array. Changes in proliferation were quantified by WST-1 assay, apoptosis by Annexin V/7-AAD flow cytometry and histone marks (acH3, H3K4me1,-2,-3) by immunoblotting. Expectedly, the EGFR wt cell lines A549 and NCI-H460 were insensitive to the growth-inhibiting effect of single-agent erlotinib (IC50 70-100µM), compared to HCC827 (IC50 <0.02μM). Treatment with panobinostat diminished growth to <50% in both EGFR wt and <30% in HCC827 cells. The combination of both drugs significantly reduced proliferation by ≥70% in A549, >95% in HCC827, but not further in NCI-H460. Panobinostat alone induced differentiation and expression of p21WAF1/CIP1 and p53 in all three cell lines, with almost no further increase when combined with erlotinib. In contrast, combination treatment additively decreased pERK, pAKT and pEGFR in A549, and synergistically induced acH3 in both adenocarcinoma lines. Surprisingly, we also saw an induction of H3K4 methylation marks in all three cell lines. In conclusion, panobinostat synergistically sensitized lung adenocarcinoma cells to the antiproliferative effects of erlotinib. Since single-agent erlotinib has only modest clinical effects in adenocarcinoma EGFR wt patients, combination therapy with an HDACi might offer a promising therapy approach to extend this activity. Copy-number analysis of three NSCLC cell lines HCC827, A549 and NCI-H460 (in unicates) was performed according to protocol by Affymetrix Genome-Wide Human SNP-Array 6.0.

ORGANISM(S): Homo sapiens

SUBMITTER: Gabriele Greve 

PROVIDER: E-GEOD-63784 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress