Abstract 4111: Vitamin D for prevention of liver cancer in the setting of disrupted TGF-β signaling pathway
Authors: Katz Lior H. , Cortes Andrea , Shukla Vivek , Machida Keigo , Tsukamoto Hidekazu , Shetty Kirty , He Aiwu R. , Johnson Lynt B. , Chen Jian , El-Zein Randa , Lee Ju-Seog , Mshra Lopa 
Published: May 2015

Hepatocellular carcinoma (HCC) is the third most common cause of cancer related death worldwide. Vitamin D (VD) has been implicated in the prevention of multiple cancers- some with inactivation of TGF-β signaling. Recently, inactivation of TGF-β signaling has been associated with HCC. We analyzed whole genome data for TGF-β signaling and examined the role of VD in the context of TGF-β inactivation in HCC. Methods: Databases of HCC Genomics (COSMIC) and transcriptomics (TCGA) were analyzed. The effect of calcitriol on cell proliferation was measured in HCC cell lines; Hep-G2 and MEF cells, with knocked down TGF-β/β2-spectrin (β2SP). Wild-type (WT), Sptbn1+/- and Smad3+/- mice were fed with diets containing 200 IU VD/kg or 10,000 IU VD/kg for 9 weeks. Hepatocyte proliferation was analyzed through Ki67 staining. The expression of cyclin D1 was evaluated by Western blotting. A whole genome gene expression profiling array was performed from liver samples of those mice using Illumina MouseWG-6 v2.0 gene expression arrays®. Lastly, liver samples from patients with HCC who had received VD supplementation were evaluated by immunohistochemistry. Results: Whole genome data revealed aberrant TGF-β signaling in ∼70% of HCCs. Treatment with calcitriol suppressed the growth of HCC cell lines, regardless of their TGF-β pathway status. Inhibition of proliferation was noted in WT MEFs as well as in the Sptbn1+/- and Sptbn1-/- cells. High dose VD reduced hepatic proliferation and cyclin D1 levels in Sptbn1+/- and Smad3+/- mutants, and in WT mice. The microarray data demonstrated the most significant changes in gene expression were associated with acute phase inflammatory response (p&lt;0.005). Validation studies showed a significant fold change difference of P-PARA, OAZ1, TLR7 and TLR 9 after high dose VD diet between WT mice and the mutants (p&lt;0.05). VD supplementation to patients with HCC was associated with higher expression of β2SP (p&lt;.0001) and TβRII (p=.013) compared with that of patients who did not receive the supplement. Conclusions: Whole genome data revealed aberrant TGF-β signaling in ∼ 70% of HCCs. VD suppresses the proliferation of HCC cell lines as well as normal hepatocytes potentially through restoring of TGF-β tumor suppressor signaling. VD modulates inflammation markedly differently in the setting of TGF-β signaling inactivation. Taken together, these results suggest that VD treatment strategies could potentially be pivotal in prevention and treatment of HCC.

Citation Format: Lior H. Katz, Andrea Cortes, Vivek Shukla, Keigo Machida, Hidekazu Tsukamoto, Kirty Shetty, Aiwu R. He, Lynt B. Johnson, Jian Chen, Randa El-Zein, Ju-Seog Lee, Lopa Mshra. Vitamin D for prevention of liver cancer in the setting of disrupted TGF-β signaling pathway. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4111. doi:10.1158/1538-7445.AM2014-4111