Transcriptional Induction of Periostin by a Sulfatase 2-TGFß1-SMAD Signaling Axis Mediates Tumor Angiogenesis in Hepatocellular Carcinoma.

Existing antiangiogenic approaches to treat metastatic hepatocellular carcinoma (HCC) are weakly effectual, prompting further study of tumor angiogenesis in this disease setting. Here, we report a novel role for sulfatase 2 (SULF2) in driving HCC angiogenesis. Sulf2-deficient mice (Sulf2 KO) exhibited resistance to diethylnitrosamine-induced HCC and did not develop metastases like wild-type mice (Sulf2 WT). The smaller and less numerous tumors formed in Sulf2 KO mice exhibited a markedly lower microvascular density. In human HCC cells, SULF2 overexpression increased endothelial proliferation, adhesion, chemotaxis, and tube formation in a paracrine fashion. Mechanistic analyses identified the extracellular matrix protein periostin (POSTN), a ligand of αvß3/5 integrins, as an effector protein in SULF2-induced angiogenesis. POSTN silencing in HCC cells attenuated SULF2-induced angiogenesis and tumor growth in vivo The TGFß1/SMAD pathway was identified as a critical signaling axis between SULF2 and upregulation of POSTN transcription. In clinical HCC specimens, elevated levels of SULF2 correlated with increased microvascular density, POSTN levels, and relatively poorer patient survival. Together, our findings define an important axis controlling angiogenesis in HCC and a mechanistic foundation for rational drug development. Cancer Res; 77(3); 632-45. ©2016 AACR.

Activation of the transforming growth factor-ß/SMAD transcriptional pathway underlies a novel tumor-promoting role of sulfatase 1 in hepatocellular carcinoma.

UNLABELLED: In vitro studies have proposed a tumor suppressor role for sulfatase 1 (SULF1) in hepatocellular carcinoma (HCC); however, high expression in human HCC has been associated with poor prognosis. The reason underlying this paradoxical observation remains to be explored. Using a transgenic (Tg) mouse model overexpressing Sulf1 (Sulf1-Tg), we assessed the effects of SULF1 on the diethylnitrosamine model of liver carcinogenesis. Sulf1-Tg mice show a higher incidence of large and multifocal tumors with diethylnitrosamine injection compared to wild-type mice. Lung metastases were found in 75% of Sulf1-Tg mice but not in wild-type mice. Immunohistochemistry, immunoblotting, and reporter assays all show a significant activation of the transforming growth factor-ß (TGF-ß)/SMAD transcriptional pathway by SULF1 both in vitro and in vivo. This effect of SULF1 on the TGF-ß/SMAD pathway is functional; overexpression of SULF1 promotes TGF-ß-induced gene expression and epithelial-mesenchymal transition and enhances cell migration/invasiveness. Mechanistic analyses demonstrate that inactivating mutation of the catalytic site of SULF1 impairs the above actions of SULF1 and diminishes the release of TGF-ß from the cell surface. We also show that SULF1 expression decreases the interaction between TGF-ß1 and its heparan sulfate proteoglycan sequestration receptor, TGFßR3. Finally, using gene expression from human HCCs, we show that patients with high SULF1 expression have poorer recurrence-free survival (hazard ratio 4.1, 95% confidence interval 1.9-8.3; P = 0.002) compared to patients with low SULF1. We also found strong correlations of SULF1 expression with TGF-ß expression and with several TGF-ß-related epithelial-mesenchymal transition genes in human HCC. CONCLUSION: Our study proposes a novel role of SULF1 in HCC tumor progression through augmentation of the TGF-ß pathway, thus defining SULF1 as a potential biomarker for tumor progression and a novel target for drug development for HCC.

Immunotherapeutic approaches to hepatocellular carcinoma treatment.

Liver cancer, the most common form of which is hepatocellular carcinoma (HCC), is one of the most deadly cancers worldwide. As of 2008, in men, HCC was the fifth most common cancer (approximately 450,000 new cases per year) and the second most frequent cause of death from cancer (around 416,000 deaths per year), whereas in women, it was the seventh most frequently diagnosed cancer (150,000 new cases per year) and the sixth most frequent cause of cancer deaths (140,000 deaths per year) [1]. Overall, HCC is the third leading cause of death from cancer globally [2, 3]. Worldwide, the incidence of HCC in males is more than twice that in females. The etiology of HCC is diverse; however, approximately 80% of HCCs occur secondary to chronic infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) [4]. The geographic distribution of HCC is such that the high-incidence regions of Eastern Asia and sub-Saharan Africa bear a disproportionate HCC burden, amounting to more than 80% of the global burden [4]. However, even in areas considered low-incidence regions-North America and Europe-the incidence of HCC is on the rise [4]. In the US, HCC incidence has risen more than threefold in the past 30 years, and it is now the ninth most frequent cause of death from cancer. The major reasons for the increased incidence of HCC in the US are the increasing prevalence of chronic HCV infection, increased immigration from high-incidence countries in Asia and Africa, and the increase in the number of individuals with cirrhosis due to obesity-related fatty liver disease. Most HCCs are diagnosed at an advanced stage for which there is no curative option. Sorafenib, the only agent specifically approved for HCC treatment, is of limited efficacy in this setting. Therefore, an urgent need for improved HCC therapy exists. In this review, we discuss the available data on the development and use of immunotherapy for HCC, with a particular focus on recent results and novel approaches.

Stromal cell-derived factor-1 signaling via the CXCR4-TCR heterodimer requires phospholipase C-ß3 and phospholipase C-γ1 for distinct cellular responses.

The CXCR4 chemokine receptor is a G protein-coupled receptor that signals in T lymphocytes by forming a heterodimer with the TCR. CXCR4 and TCR functions are consequently highly cross regulated, affecting T cell immune activation, cytokine secretion, and T cell migration. The CXCR4-TCR heterodimer stimulates T cell migration and activation of the ERK MAPK and downstream AP-1-dependent cytokine transcription in response to stromal cell-derived factor-1 (SDF-1), the sole chemokine ligand of CXCR4. These responses require Gi-type G proteins as well as TCR ITAM domains and the ZAP70 tyrosine kinase, thus indicating that the CXCR4-TCR heterodimer signals to integrate G protein-coupled receptor-associated and TCR-associated signaling molecules in response to SDF-1. Yet, the phospholipase C (PLC) isozymes responsible for coupling the CXCR4-TCR heterodimer to distinct downstream cellular responses are incompletely characterized. In this study, we demonstrate that PLC activity is required for SDF-1 to induce ERK activation, migration, and CXCR4 endocytosis in human T cells. SDF-1 signaling via the CXCR4-TCR heterodimer uses PLC-ß3 to activate the Ras-ERK pathway and increase intracellular calcium ion concentrations, whereas PLC-γ1 is dispensable for these outcomes. In contrast, PLC-γ1, but not PLC-ß3, is required for SDF-1-mediated migration via a mechanism independent of LAT. These results increase understanding of the signaling mechanisms employed by the CXCR4-TCR heterodimer, characterize new roles for PLC-ß3 and PLC-γ1 in T cells, and suggest that multiple PLCs may also be activated downstream of other chemokine receptors to distinctly regulate migration versus other signaling functions.

Physiological and morphological correlates of among-individual variation in standard metabolic rate in the leopard frog Rana pipiens.

Rates of standard metabolism (SMR) are highly variable among individuals within vertebrate populations. Because SMR contributes a substantial proportion of an individual's energy budget, among-individual variation in this trait may affect other energetic processes, and potentially fitness. Here, we examine three potential proximate correlates of variation in SMR: organ mass, serum T4 thyroxine and relative mitochondrial content, using flow cytometry. Body-mass-adjusted kidney mass correlated with SMR, but liver, heart, small intestine and gastrocnemius did not. Thyroxine correlated with SMR, as did mitochondrial content. These results suggest several novel proximate physiological and morphological mechanisms that may contribute to among-individual variation in SMR. Variation in SMR may be maintained by diverse environmental conditions. Some conditions, such as low resource availability, may favor individuals with a low SMR, through small organ size, or low thyroxine or mitochondrial content. Other conditions, such as high resource availability, may favor individuals with a high SMR, through large organ size, or high thyroxine or mitochondrial content.