Abstract 4848: The functional synergism and pro-metastatic role of FOXM1 and CENPF in hepatocellular carcinoma
Authors: Lam Wai Ling Macrina , Chan Lo Kong , Ho Daniel Wai-Hung , Kam Charles Shing , Ng Irene Oi-Lin 
Published: July 2017

Hepatocellular carcinoma (HCC) is the second leading cause of cancer death worldwide and metastasis is regarded as the major cause of HCC-associated lethality. In this study, we have analysed the TCGA whole-transcriptome sequencing data of paired human HCC samples (n=50), and identified Forkhead Box M1 (FOXM1) and Centromere Protein F (CENPF) to be the top-listing upregulated genes. Interestingly, both of them are the essential components in cell-cycle progression. FOXM1 encodes for the cell-cycle-dependent transcription factor that regulates genes for DNA replication and mitosis, while CENPF encodes for the centromere protein that is required for kinetochore function and chromosome segregation in mitosis.

We hypothesized that the upregulation of FOXM1-CENPF signaling axis may drive hepatocarcinogenesis. In our human HCC cohort (n=34), FOXM1 and CENPF were shown to be upregulated compared with the non-tumorous liver tissues, and their mRNA expressions were positively correlated (p&lt;0.0001). Co-upregulation of FOXM1 and CENPF in patient samples was demonstrated to be positively correlated with the absence of tumor encapsulation (p=0.035) in our clinico-pathological correlation analysis, whereas the samples without their co-upregulation was less likely to be correlated with venous invasion (p =0.045). This indicated that FOXM1 and CENPF are likely to be associated with HCC metastasis synergistically.

Stable single and co-knockdown clones of FOXM1 and CENPF in four HCC cell lines (BEL7402, SMMC-7721, MHCC-97L, Huh7) were established using short-hairpin (sh) RNA approach for subsequent functional characterization. Both single and co-knockdown of FOXM1 and CENPF cells have shown reduced proliferation rate (p&lt;0.05) in cell proliferation assay. Moreover, all single and co-knockdown of FOXM1 and CENPF cell lines were found to have a at least 2-fold reduction in migration and invasion rate (p&lt;0.0001) in transwell cell migration and invasion assay. These suggested that FOXM1 and CENPF are critical for HCC cell proliferation, migration and invasion.

To assess the translational significance of targeting FOXM1 and CENPF, seven HCC cell lines (BEL7402, SMMC-7721, MHCC-97L, Huh7, Hep3B, HepG2, PLC/PRF/5) were challenged with thiostrepton and zoledronic acid, which are inhibitors against FOXM1 and CENPF, respectively. Intriguingly, both individual and combined treatments of these inhibitors effectively inhibited HCC cell growth. It was also demonstrated that such inhibition acts via suppressing the respective endogenous transcript and protein expression of FOXM1 and CENPF. Taken together, our study has demonstrated that FOXM1 and CENPF play a critical oncogenic role in HCC and they may function as an attractive molecular therapeutic target.

This study is supported in part by Health and Medical Research Fund (03142836).

Citation Format: Wai Ling Macrina Lam, Lo Kong Chan, Daniel Wai-Hung Ho, Charles Shing Kam, Irene Oi-Lin Ng. The functional synergism and pro-metastatic role of FOXM1 and CENPF in hepatocellular carcinoma [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 4848. doi:10.1158/1538-7445.AM2017-4848