Abstract 3113: Knockdown of cell division cycle-associated 8 (CDCA8) suppresses hepatocellular carcinoma growth via the upregulation of tumor suppressor ATF3

Abstract

Abstract Background: Hepatocellular carcinoma (HCC) is the third most lethal cancer worldwide which remains a major challenge due to poor prognosis and limited treatment options. Cell division cycle associated 8 (CDCA8) is known as a component of a chromosomal passenger complex required for stability of the bipolar mitotic spindle and it is commonly overexpressed in human HCC. However, the functional role of CDCA8 in HCC progression remains to be clarified. In this study, we hypothesized if targeting of CDCA8 with small interfering (si) RNA could alter the course of HCC progression. We also investigated the molecular mechanism that mediates HCC cell death caused by CDCA8 silencing. Methods: Human HCC cell lines, Huh1 and Huh7, were transfected with CDCA8 siRNA and tested for growth inhibition and apoptotic induction using MTS, FACS and microscopic analysis. To obtain insights into the molecular changes in response to CDCA8 knockdown, global changes in gene expression were examined using RNA sequencing. Results: siRNA silencing of CDCA8 inhibited HCC cell growth and long-term colony formation by blocking cell cycle progression and by inducing apoptotic cell death. RNA sequencing data showed that, representatively, the anti-proliferative effects were driven by a subset of molecular alterations including the upregulation of tumor suppressive ATF3 and GADD34 genes and the downregulation of BGLAP, a key regulator of cell growth and invasiveness. Subsequent Western blot analysis affirmed that CDCA8 silencing induces the increase in the levels of ATF3 and GADD34 and the decrease in phosphorylated Akt in both Huh1 and Huh7 cells. Also, the same condition decreased the levels of PARP-1 and pro-caspase 3, accelerating apoptosis. Of importance, silencing of CDCA8 expression effectively suppressed HCC tumor growth in a murine xenograft model. Conclusion: These findings suggest that targeting CDCA8 could be an attractive option for molecular therapy of HCC. Citation Format: Tae-Won Jeon, Min Ji Ko, Yu-Ri Seo, In Hye Baik, Ilseon Hwang, Hun-Mo Ryoo, Jin Young Kim, Keon Uk Park, Yun-Han Lee. Knockdown of cell division cycle-associated 8 (CDCA8) suppresses hepatocellular carcinoma growth via the upregulation of tumor suppressor ATF3 [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 3113. doi:10.1158/1538-7445.AM2017-3113