Hsp90 Inhibition Leads To A Differential Proteomics Profile In Non Small Cell Lung Cancer Cell Lines

Background: The cancer chaperone, Heat Shock Protein 90 (HSP90), is known for its ability to regulate the stability of different oncogenic proteins. Thus, its overexpression has been related to unfavorable prognosis in some types of tumors. EGFR and EML4-ALK, two of the most important drivers in non-small cell lung cancer (NSCLC), are HSP90 clients and extremely depend on it. As a consequence, this chaperone is especially important in NSCLC hence HSP90 inhibition shows a lot of possibilities to future treatments in this tumor type. Nevertheless, to obtain a successful clinical development, will be essential supporting evidence of inhibitory efficacy in several molecularly defined subgroups of NSCLC. Methods: NSCLC cell lines carrying different gene mutations, whose direct (HCC827: EGFR mutated and H3122: EML4-ALK rearrangement) and indirect (A549: KRAS mutated) relationship with HSP90 has been reported, were used. In these cell lines, along with H1781 (EGFR, KRAS, ALK wild type) as control, the activity of the chaperone studied was interrupted. To this end, pharmacological inhibition of HSP90 was achieved through geldanamycin and resorcinol derivates. First, western blotting was carried out to confirm the effect of this inhibition. Later, to identify a proteomic profile associated with HSP90 inhibition, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) of selected cell lines were performed. Results: The expression of the oncogenic HSP90 client proteins studied was decreased by the inhibitors in the NSCLC cell lines. The oncoproteins drivers EGFR and EML4-ALK showed a strong dependence on HSP90 observed through a high sensitivity of the cell lines HCC827 and H3122 to the inhibition. Therefore, these cell lines were selected with the purpose of identify a proteomic signature linked to HSP90 inhibition by 2D-PAGE. The untreated EGFR positive cell line presented 104 protein spots significantly up-regulated, whereas 80 spots were down-regulated compared to inhibited cell line. Meanwhile, the cell line harboring the EML4-ALK translocation showed 16 spots up-regulated and 5 down-regulated in the untreated versus inhibited cell line. In addition HSP70 overexpression, compared to unprocessed cell lines, was detected after treatments. This feedback, previously reported, confirmed HSP90 inhibition in the two cell lines studied. Conclusions: The evidence of treatment response, in the cell lines studied, was showed through oncogenic client proteins reduction as well as HSP70 induction. The proteomic profiles identified, of HSP90 inhibited and untreated tumor cells, revealed several deregulated pathways involved in the tumorigenesis. Citation Format: Angela Marrugal, Irene Ferrer, Maria Dolores Pastor, Alvaro Quintanal, Antonio Lucena-Cacace, Amancio Carnero, Luis Paz-Ares, Sonia Molina-Pinelo. HSP90 inhibition leads to a differential proteomics profile in non small cell lung cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2207. doi:10.1158/1538-7445.AM2017-2207