Sonic Hedgehog signaling pathway as a potential target to inhibit the progression of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated mortality worldwide. Hepatocarcinogenesis involves numerous interlinked factors and processes, including the Sonic hedgehog (Shh) signaling pathway, which participates in the carcinogenesis, progression, invasiveness, recurrence and cancer stem cell maintenance of HCC. The Shh signaling pathway is activated by ligands that bind to their receptor protein, Protein patched homolog (Ptch). The process of Shh ligand binding to Ptch weakens the inhibition of smoothened homolog (SMO) and activates signal transduction via glioma-associated oncogene homolog (Gli) transcription factors. The overexpression of Shh pathway molecules, including Shh, Ptch-1, Gli and SMO has been indicated in patients with HCC. It has also been suggested that the Shh signaling pathway exhibits cross-talk between numerous other signaling pathways. The inactivation of the Shh signaling pathway reduces HCC growth, increases radio-sensitivity and increases the beneficial effect of chemotherapy in HCC treatment. Therefore, inhibition of the Shh pathway may be an effective target therapy that can be used in the treatment of HCC.

Tropism of liver epithelial cells toward hepatocellular carcinoma in vitro and in vivo with altering gene expression of cancer stem cells.

BACKGROUND: Rat liver epithelial (RLE) cells could inhibit the proliferation and invasiveness of hepatoma cells in vitro. This study is to understand the tropism and the effect of RLE cells on mouse hepatoma cells both in vitro and in vivo. METHODS: RLE cells were isolated from new-born rats and characterized their stem cell markers. Co-culture and HCC mouse model was established to detect therapeutic effect of RLE cells. RESULTS: RLE cells (including Thy-1+ RLE cells, Thy-1- RLE cells, RLE cells) displayed a selective tropism toward ML-1 hepatoma cells both in vitro and in vivo. They altered the gene expression of some cancer stem cell markers in the liver tumor. CONCLUSION: Liver epithelial cells have a selective tropism toward HCC in vitro and in vivo. They could alter the gene expression of cancer stem cells.

Liver epithelial cells inhibit proliferation and invasiveness of hepatoma cells.

Hepatocellular carcinoma (HCC) is a worldwide malignancy with poor prognosis. Liver progenitors or stem cells could be a potential therapy for HCC treatment since they migrate toward tumors. Rat liver epithelial (RLE) cells have both progenitor and stem cell-like properties. Therefore, our study elucidated the therapeutic effect of RLE cells in rat hepatoma cells. RLE cells were isolated from 10-day old rats and characterized for stem cell marker expression. RLE cells and rat hepatoma cells (H4-IIE-C3 cells) were co-cultured and divided into four groups with different ratios of RLE and hepatoma cells. Group A had only rat hepatoma cells as a control group. The ratios of rat hepatoma and RLE cells in group B, C and D were 5:1, 1:1 and 1:5, respectively. Effective inhibition of cell proliferation and migration was found in group D when compared to group A. There was a significant decrease in Bcl2 expression and increase in late apoptosis of rat hepatoma cells when adding more RLE cells. RLE cells reduced cell proliferation and migration of rat hepatoma cells. These results suggested that RLE cells could be used as a potential cell therapy.

Protective role of wogonin against lipopolysaccharide-induced angiogenesis via VEGFR-2, not VEGFR-1.

Wogonin, one of flavonoid derived from particular plants, enriches the property of anti-inflammation. Inflammation-stimulated angiogenesis plays an important role in many pathological diseases, such as rheumatoid arthritis, atherosclerosis, and cancer. The aim of this study was to investigate the suppressive effect of wogonin on lipopolysaccharide (LPS)-induced angiogenesis in human umbilical endothelial cell (HUVEC) cultures. By cell differentiation assays, migration and tube formation activity under LPS treatment were evaluated. Besides, IL-6 neutralizing antibody was added to test the inhibitory effect in the phenotypic alteration. Western blot analysis, ELISA cytokine assay, and quantitative real time-PCR were performed for VEGF, IL-6, VEGF receptors, and IL-6 receptor gene expressions on HUVEC with wogonin treatment. Furthermore, in vivo chorioallantoic membrane (CAM) assay was applied to evaluate the percentage of new vessels formation. The results revealed that wogonin (10(-8)-10(-5) M) inhibited LPS-induced angiogenesis in a concentration-dependent manner. The mRNA and protein expressions of VEGF, VEGFR-2, IL-6, and sIL-6Ralpha were attenuated (P<0.05), but not VEGFR-1. In the LPS-induced CAM model, our data suggested that wogonin (10(-8)-10(-5) M) significantly decreased new vessel formation and vascular network (P<0.05). We conclude that wogonin suppresses both in vitro and in vivo LPS-induced angiogenesis, through VEGFR-2, but not VEGFR-1.

Chrysin inhibits lipopolysaccharide-induced angiogenesis via down-regulation of VEGF/VEGFR-2(KDR) and IL-6/IL-6R pathways.

The relationship between chrysin and inflammation-induced angiogenesis remains unclear. The aim of this study was to evaluate the suppressive effects of chrysin on lipopolysaccharide (LPS)-induced angiogenesis in chicken chorioallantoic membrane (CAM) as well as in human umbilical endothelial cells (HUVEC). The IN VIVO CAM model was applied to evaluate the percentage of new vessels formation, followed by measuring endothelial migration and tube formation in HUVEC cultures. The mechanisms of the suppressive effect of chrysin on LPS-induced angiogenesis, in terms of VEGF, VEGF receptors (VEGFR), interleukin 6 (IL-6) and IL-6 receptor gene expressions, were analyzed by Western blot, ELISA cytokine assay, and quantitative real time PCR. The results showed that chrysin (10(-8) - 10(-5) M) inhibited LPS-induced CAM neovascular density. There was a significant down-regulation of VEGF and VEGFR-2 (KDR) but not VEGFR-1 (Flt-1) gene expression by chrysin in LPS-treated HUVEC cultures. Besides, chrysin concentration-dependently inhibited the auto-regulation loop of IL-6/IL-6R in LPS-treated HUVEC cells. We conclude that chrysin suppresses both IN VITRO and IN VIVO LPS-induced angiogenesis.

Potential of faecal RNA in diagnosing colorectal cancer.

Early diagnosis for colorectal cancer (CRC) by monitoring of gastrointestinal epithelial cells is a possible direct approach. Although human faeces form a heterogeneous mixture of gastrointestinal mucosal epithelial cells and other materials, we have developed a method to purify total RNA from human stool samples. The gene for faecal cytokeratin 19 (CK19) was highly expressed in stools from patients with metastatic CRC, but not from patients with non-metastatic CRC or from normal individuals. Thus, purified faecal RNA can be used for the detection of differentially expressed genes. This technique may help identifying meaningful faecal RNA markers for the non-invasive screening of patients with CRC.

Silibinin inhibits angiogenesis via Flt-1, but not KDR, receptor up-regulation.

BACKGROUND: Our previous study found that silymarin (SM) and its major pure component silibinin (SB) have anti-angiogenic effects via decreased vascular endothelium growth factor (VEGF) secretion of LoVo cells (colon cancer). We designed this consecutive study to evaluate the anti-angiogenic effects of SM/SB in vivo, and on VEGF receptor (VEGFR) gene expression. MATERIALS AND METHODS: We used LoVo cells exposed to SM/SB in a modified chicken chorioallantoic membrane assay (CAM) to evaluate anti-angiogenic effects. We used EA.hy 926 cells (endothelial cells) exposed to SM/SB to evaluate the effect on VEGFR-1 (Flt-1) and VEGFR-2 (KDR), with 1-step, real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In CAM, SM/SB showed a dose-dependent decrease on the vascular density index (VDI) induced by LoVo cells, as did thalidomide in a concentration of 10 microg/ml. Adding escalating dosages of VEGF successfully reversed this inhibitory effect. RT-PCR revealed that SB up-regulated Flt-1 mRNA expression of EA.hy 926 cells. SM had a similar trend, although the effect was not statistically significant (P = 0.19). Neither drug effected KDR mRNA expression. CONCLUSION: We conclude that anti-angiogenic effects of SM/SB are associated with the up-regulation of VEGFR-1 (Flt-1) gene expression and that they are good candidates for combination therapy to treat colorectal cancer.