Abstract 1750: Analysis of non-metastatic HCC patient tumors revealed the significance of cell cycle regulation and tumor immunity in association with overall survival and identified clinically relevant druggable targets
Authors: Miao Pei-Zhen , Cheng Jeff , Okrah Kwame , Liu Bonnie , Sun Charlie , Cao Grace , Guo Tony , Fu Shijing , Wagle Marie-Claire , Blackwood Elizabeth , Shames David , Hampton Garret , Amler Lukas , Kiermaier Astrid , Fridlyand Yevgeniya , Lackner Mark , Huang Shih-Min , Zhou Jian , Dai Zhi 
Published: July 2017

The lack of efficacious therapies have hindered the progress in improving the survival of HCC patients worldwide. As a disease that associates with the underlying liver injuries caused by various etiologies and remains asymptomatic during most of its decades long progression, HCC presents challenges to accurately depict its biological landscape and determine suitable therapeutic intervention. An approach to tackle this issue is to define significant biological variants that impact patient survival in each disease stage, then attempt to chart paths of potential therapies.

To identify significant biological determinants associated with the overall survival (OS) of early stage, non-metastatic HCC patients, we constructed focused Nanostring panels that are represented by 1,164 genes of validated components and transcriptional outputs of multiple signaling pathways, cellular machineries, and tumor immunity. An unbiased analysis of patient survival and gene transcript levels revealed four distinct groups of genes that are significantly prognostic. The first two (Group 1 & 2) are associated with poorer prognosis when expression is high (hazard ratio &gt; 2), whereas the remaining two (Group 3 & 4) correspond to significantly better OS with elevated transcript levels (hazard ratio&lt;0.5). Of note, Gene Set Enrichment Analyses (GSEA) clearly indicated that while Group 2 was substantially enriched in genes positively regulating cell cycle and cell division machinery, Group 4 was overrepresented by genes participating in the positive modulation and feedback mechanisms of adaptive immune response, implicating the survival benefit of acquiring higher immunogenic tumor environment in early stage HCC.

Searching for druggable targets associated with poorer prognosis, we identified both EZH2 and CHEK1 as candidates from Group 2. In vitro treatment of three HCC cell lines with EPZ-6438 (EZH2 inhibitor) or GDC-0425 (CHEK1 inhibitor) resulted in significant modulation of H3K27me3 or pCHEK1 levels (s345) respectively. The growth of these cell lines was also dose-dependently suppressed by each inhibitor in colony formation assays . Furthermore, the combination of both inhibitors was able to achieve substantial cell growth inhibition at lower concentrations, suggesting a combinatorial effect of targeting both EZH2 and CHEK1 in HCC cell lines. Xenograft studies are ongoing to assess in vivo efficacy of this combination.

In conclusion, utilizing well constructed Nanostring gene panels, we identified significant association of cell cycle machinery and adaptive tumor immunity with HCC patient survival. Our findings not only provided potential rationale for expand testing of cancer immunotherapies to non-metastatic, early stage HCC, but also revealed the potential utility of combining EZH2 and CHEK1 inhibitors to treat HCC.

Citation Format: Pei-Zhen Miao, Jeff Cheng, Kwame Okrah, Bonnie Liu, Charlie Sun, Grace Cao, Tony Guo, Shijing Fu, Marie-Claire Wagle, Elizabeth Blackwood, David Shames, Garret Hampton, Lukas Amler, Astrid Kiermaier, Yevgeniya Fridlyand, Mark Lackner, Shih-Min Huang, Jian Zhou, Zhi Dai. Analysis of non-metastatic HCC patient tumors revealed the significance of cell cycle regulation and tumor immunity in association with overall survival and identified clinically relevant druggable targets [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 1750. doi:10.1158/1538-7445.AM2017-1750