Role of HGF/c-Met in the treatment of colorectal cancer with liver metastasis.

The system of hepatocyte growth factor (HGF) and its receptor c-Met plays a critical role in tumor invasive growth and metastasis. The mortality rate of colorectal cancer (CRC), one of the most commonly diagnosed malignancies, is increased by it gradual development into metastasis, most frequently in the liver. Overexpression of c-Met, the protein tyrosine kinase receptor for the HCF/scatter factor, has been implicated in the progression and metastasis of human colorectal carcinoma. In this study, we aimed to investigate the role of c-Met in CRC liver metastasis and illustrate the clinical impact of regulating HGF/c-Met signaling in patients with CRC liver metastasis. We found that (I) higher levels of c-Met expression (mRNA and Protein) in CRC liver metastasis than primary CRC by assessing the patient tissue samples; (II) a positive correlation of c-Met expression with tumor stages of CRC liver metastasis, as well as c-Met expression in CRC, live metastasis concurred with regional lymph node metastasis; (III) the clinical impact of downregulation of HGF/c-Met signaling on the reduction of proliferation and invasion in CRC liver metastasis. Therefore, we demonstrate that the regulation of HGF/c-Met pathways may be a promising strategy in the treatment of patients with CRC liver metastasis.

Overexpression of caudal-related homeobox transcription factor 2 inhibits the growth of transplanted colorectal tumors in nude mice.

Caudal­related homeobox transcription factor 2 (CDX2) is a transcription factor, which is specifically expressed in the adult intestine. It is essential for the development and homeostasis of the intestinal epithelium and its functions as a tumor suppressor have been demonstrated in the adult colon. The present study aimed to examine the inhibitory effects of the overexpression of CDX2 on subcutaneously­transplanted tumors, derived from LoVo colon cancer cells, in nude mice, and to provide experimental evidence for the biotherapy of colon cancer. A pEGFP­C1­CDX2 eukaryotic expression vector was transfected into the LoVo cells via lipofection, and LoVo cells stably­expressing CDX2 (pEGFP­C1­CDX2 cells) were obtained using G418 selection. A nude mouse subcutaneously­transplanted tumor model was established by inoculating the nude mice with the pEGFP­C1­CDX2 cells, and the effects of overexpression of CDX2 on transplanted tumor growth in the LoVo cells were observed. Western blotting results demonstrated that the protein expression of CDX2 in the LoVo cells was higher in the pEGFP­C1­CDX2 cell group, compared with that in the pEGFP­C1 cell group and the untreated cell group. At 20 days post­inoculation with either pEGFP­C1­CDX2 or pEGFP­C1, the transplanted tumor masses were significantly lower in the pEGFP­C1­CDX2 group, compared with those in the pEGFP­C1 and untreated groups. Immunohistochemistry revealed that the expression levels of CDX2 and matrix metalloproteinase­2 (MMP­2) were detected in each group, and the protein expression of CDX2 was increased in the tumor tissues from the nude mice in the pEGFP­C1­CDX2 group. However the expression of MMP­2 was downregulated in the tumor tissues of the nude mice in the pEGFP­C1­CDX2 group. Taken together, these data suggested that pEGFP­C1­CDX2 cells exhibited suppressed tumor growth in vivo. Overexpression of CDX2 was observed in transplanted tumors in the pEGFP­C1­CDX2 group, and the gene expression of MMP­2 was reduced. These results indicate that CDX2 inhibited the growth of colorectal tumor cells, possibly by downregulating the gene expression.

[The protective effect of chlorophyllin against oxidative damage and its mechanism].

OBJECTIVE: To investigate whether chlorophyllin could protect human umbilical vein endothelial cell (HUVEC) against oxidative damage by inducing the expression of heme oxygenase-1 (HO-1) and to explore the underlying mechanism. METHODS: The cellular protection of chlorophyllin against oxidative damage was detected by cell-survival assay with flow cytometry. The level of free radicals was detected directly by electron spin resonance spectra. The induced expression of HO-1 was shown by RT-PCR, Western blot, immunofluorescence confocal laser microscopy and enzymatic activity test. Whether the activation of PI3K/Akt pathway was involved was detected by Western blot. RESULTS: Chlorophyllin could protect HUVEC against oxidative damage caused by H2O2 via scavenging the excessive free radicals. Chlorophyllin treatment could induce expression of HO-1 in a dose- and time-dependent manner. The activation of PI3K/Akt pathway was required in the induction of HO-1. LY294002, the specific inhibitor of PI3K, could suppress the activation of PI3K/Akt and the induced expression of HO-1 in a dose-dependent manner. CONCLUSIONS: Chlorophyllin shows cellular protection against oxidative damage by counteracting the excessive free radicals. Up-regulation of HO-1 expression plays a pivotal role in the protection of chlorophyllin, while the activation of PI3K/Akt signaling pathway is required in the induction of HO-1.