DIPG-41. IDENTIFICATION OF BIRC5 AS A NOVEL THERAPEUTIC TARGET FOR DIFFUSE INTRINSIC PONTINE GLIOMA

Abstract

Diffuse Intrinsic Pontine Glioma (DIPG) remains to be a lethal type of pediatric brain tumor to date, indicating an urgent need of finding novel therapeutic strategy. Through screening of a collection of anti-tumor agents against a patient-derived DIPG primary tumor cell line, we identified a few novel therapeutic candidates for treating DIPG, among which BIRC5 inhibitor YM155 was the top potent agent. Next, we confirmed that YM155 could selectively inhibit multiple DIPG primary cell lines with IC50 less than 10nM. Moreover, our gene expression analyses showed that BIRC5 was significantly upregulated in DIPG primary tumor tissues and paired normal cortex tissues from the same patient. Genetically targeting of BIRC5 with CRISPR-Cas9 or RNAi approach could also effectively disrupt the growth of multiple DIPG cell lines, confirming BIRC5 as a valid therapeutic target for treating DIPG. Mechanistically, BIRC5 inhibition could cause cell cycle arrest, shut off proliferation and induce massive apoptosis. Furthermore, we tested the combinatory inhibitory effects of YM155 plus chemotherapy or targeted therapy drugs with proven anti-DIPG activity, including THZ1, JQ1, Gemcitabine, Panobinostat, GSK-J4 and et al. The preliminary results demonstrated YM155 could work synergistically with a few of above-mentioned drugs in vitro. We are also testing the in vivo inhibitory effects of targeting BIRC5 against DIPG preclinical PDX models. Together, our study identified BIRC5 inhibition as a novel therapeutic strategy against DIPG.