Small molecule inhibitors of Late SV40 Factor (LSF) abrogate hepatocellular carcinoma (HCC): evaluation using an endogenous HCC model

Hepatocellular carcinoma (HCC) is a lethal malignancy with high mortality and poor prognosis. Oncogenic transcription factor Late SV40 Factor (LSF) plays an important role in promoting HCC. A small molecule inhibitor of LSF, Factor Quinolinone Inhibitor 1 (FQI1), significantly inhibited human HCC xenografts in nude mice without harming normal cells. Here we evaluated the efficacy of FQI1 and another inhibitor, FQI2, in inhibiting endogenous hepatocarcinogenesis. HCC was induced in a transgenic mouse with hepatocyte-specific overexpression of c-myc (Alb/c-myc) by injecting N-nitrosodiethylamine (DEN) followed by FQI1 or FQI2 treatment after tumor development. LSF inhibitors markedly decreased tumor burden in Alb/c-myc mice with a corresponding decrease in proliferation and angiogenesis. Interestingly, in vitro treatment of human HCC cells with LSF inhibitors resulted in mitotic arrest with an accompanying increase in CyclinB1. Inhibition of CyclinB1 induction by Cycloheximide or CDK1 activity by Roscovitine significantly prevented FQI-induced mitotic arrest. A significant induction of apoptosis was also observed upon treatment with FQI. These effects of LSF inhibition, mitotic arrest and induction of apoptosis by FQI1s provide multiple avenues by which these inhibitors eliminate HCC cells. LSF inhibitors might be highly potent and effective therapeutics for HCC either alone or in combination with currently existing therapies.The present study was supported in part by grants from The James S. McDonnell Foundation, National Cancer Institute Grant R01 CA138540-01A1 (DS), National Institutes of Health Grant R01 CA134721 (PBF), the Samuel Waxman Cancer Research Foundation (SWCRF) (DS and PBF), National Institutes of Health Grants R01 GM078240 and P50 GM67041 (SES), the Johnson and Johnson Clinical Innovation Award (UH), and the Boston University Ignition Award (UH). JLSW was supported by Alnylam Pharmaceuticals, Inc. DS is the Harrison Endowed Scholar in Cancer Research and Blick scholar. PBF holds the Thelma Newmeyer Corman Chair in Cancer Research. The authors acknowledge Dr. Lauren E. Brown (Dept. Chemistry, Boston University) for the synthesis of FQI1 and FQI2, and Lucy Flynn (Dept. Biology, Boston University) for initially identifying G2/M effects caused by FQI1. (James S. McDonnell Foundation; R01 CA138540-01A1 - National Cancer Institute; R01 CA134721 - National Institutes of Health; R01 GM078240 - National Institutes of Health; P50 GM67041 - National Institutes of Health; Samuel Waxman Cancer Research Foundation (SWCRF); Johnson and Johnson Clinical Innovation Award; Boston University Ignition Award; Alnylam Pharmaceuticals, Inc.)Published versio

Multifunction Protein Staphylococcal Nuclease Domain Containing 1 (SND1) Promotes Tumor Angiogenesis in Human Hepatocellular Carcinoma through Novel Pathway That Involves Nuclear Factor κB and miR-221

Staphylococcal nuclease domain-containing 1 (SND1) is a multifunctional protein that is overexpressed in multiple cancers, including hepatocellular carcinoma (HCC). Stable overexpression of SND1 in Hep3B cells expressing a low level of SND1 augments, whereas stable knockdown of SND1 in QGY-7703 cells expressing a high level of SND1 inhibits establishment of xenografts in nude mice, indicating that SND1 promotes an aggressive tumorigenic phenotype. In this study we analyzed the role of SND1 in regulating tumor angiogenesis, a hallmark of cancer. Conditioned medium from Hep3B-SND1 cells stably overexpressing SND1 augmented, whereas that from QGY-SND1si cells stably overexpressing SND1 siRNA significantly inhibited angiogenesis, as analyzed by a chicken chorioallantoic membrane assay and a human umbilical vein endothelial cell differentiation assay. We unraveled a linear pathway in which SND1-induced activation of NF-κB resulted in induction of miR-221 and subsequent induction of angiogenic factors Angiogenin and CXCL16. Inhibition of either of these components resulted in significant inhibition of SND1-induced angiogenesis, thus highlighting the importance of this molecular cascade in regulating SND1 function. Because SND1 regulates NF-κB and miR-221, two important determinants of HCC controlling the aggressive phenotype, SND1 inhibition might be an effective strategy to counteract this fatal malady

Staphylococcal nuclease domain containing-1 (SND1) promotes migration and invasion via angiotensin II type 1 receptor (AT1R) and TGFβ signaling

Staphylococcal nuclease domain containing-1 (SND1) is overexpressed in human hepatocellular carcinoma (HCC) patients and promotes tumorigenesis by human HCC cells. We now document that SND1 increases angiotensin II type 1 receptor (AT1R) levels by increasing AT1R mRNA stability. This results in activation of ERK, Smad2 and subsequently the TGFβ signaling pathway, promoting epithelial–mesenchymal transition (EMT) and migration and invasion by human HCC cells. A positive correlation was observed between SND1 and AT1R expression levels in human HCC patients. Small molecule inhibitors of SND1, alone or in combination with AT1R blockers, might be an effective therapeutic strategy for late-stage aggressive HCC