Abstract 2642: BID expression levels determine cell fate upon AURKB inhibition

Background: Aurora kinase B (AURKB) plays a key role in the regulation of mitosis, and AURKB inhibitors are in Phase II-III clinical trials. We reported previously that Chr22q11 amplification, leading to BID overexpression, was associated with apoptosis in upon AURKB inhibition (AURKBi) in NSCLC cell lines resistant to EGFR TKIs. However, it remains to be elucidated whether high levels of BID expression are associated with sensitivity to AURKBi beyond NSCLC and Chr22q11 amplification. Methods: A panel of 11 solid tumor cell lines were used in the study. Also included were the EGFR-mut cell lines PC9 and 11-18, and 36 EGFR-TKI resistant clones derived from them. FISH and Q-PCR were used to determine copy number status; mRNA expression was studied by nCounter and RT-Q-PCR and protein expression by Western blotting. The effects of drugs were analyzed by MTT and flow cytometry. CRISPR-Cas9 technology was used for KO generation while ectopic expression was achieved by cloning the BID gene into a doxycycline-inducible pTRIPZ vector. Finally, in vivo experiments were performed by implanting tumor cells into athymic nude mice. Results: First, we analyzed copy numbers of BID and other 22q11 genes, together with BID expression levels, in the 49 cell lines included in the study. Then, we determined the dose-response curves of the cell lines for AZD2811, a specific AURKB inhibitor. We found that tumor cells with high BID expression levels were consistently sensitive to AURKB inhibition, independently of 22q11 amplification, while cell lines with low BID expression were uniformly resistant (r=0.91, p