Introduction. Critical role of anti-angiogenesis and VEGF inhibition in colorectal cancer

Carbonic Anhydrase VIII (CAVIII) Gene Mediated Colorectal Cancer Growth and Angiogenesis through Mediated miRNA 16-5p

Carbonic anhydrase VIII (CAVIII) is a member of the CA family, while CA8 is the oncogene. Here we observed increased expression of CAVIII with high expression in colorectal cancer tissues. CAVIII is also expressed in more aggressive types of human colorectal cancer cells. Upregulated CAVIII expression in SW480 cell lines increased vascular endothelial growth factor (VEGF) and reduced miRNA16-5p. Conversely, knockdown of the CAVIII results in VEGF decline by up-regulated miRNA16-5p. Moreover, the collection of different grades of CAVIII expression CRC cells supernatant co-culture with endothelial progenitor cells (EPCs) promotes the ability of tube formation in soft agar and migration in the Transwell experiment, indicating that CAVIII might facilitate cancer-cell-released VEGF via the inhibition of miRNA16-5p signaling. Furthermore, in the xenograft tumor angiogenesis model, knockdown of CAVIII significantly reduced tumor growth and tumor-associated angiogenesis. Taken together, our results prove that the CAVIII/miR-16-5p signaling pathway might function as a metastasis suppressor in CRC. Targeting CAVIII/miR-16-5p may provide a strategy for blocking its metastasis.

Relationship between EZH2 and VEGF expression and prognosis in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. However, its exact pathogenesis and independent prognostic factors are still unclear. In this study, we analyzed the expression of enhancer of zeste homolog 2 (EZH2) and vascular endothelial growth factor (VEGF) genes in CRC by using bioinformatics method and their relationship with prognosis. The expression of EZHE2 and VEGF proteins and their relationship with the patients' clinical characteristics were detected by immunohistochemistry.

AIM

To investigate the expression and mutation status of EZH2 and VEGF in CRC and their relationship with clinicopathological features and prognosis.

METHODS

The expression of EZH2 and VEGF genes in CRC and tumor adjacent tissues was compared in the TCGA database, and the mutations of EZH2 and VEGF genes were analyzed. The expression network of EZH2 and VEGF genes was established with the STRING database and the key genes in the network were screened. According to the expression of EZH2 and VEGF in tumor tissues, the patients were divided into high and low expression groups. Cox regression model and log-rank test were used to compare the difference of total survival and disease-free survival between the high and low expression groups. In addition, 80 patients with CRC who underwent surgery were selected, and their cancer tissues and adjacent tissues were collected. The expression of EZH2 and VEGF proteins in the above tissues was detected by immunohistochemistry.

RESULTS

Analysis based on the TCGA database showed that the expression levels of EZH2 and VEGF genes in CRC tissues were significantly higher than those in matched normal intestinal epithelial tissues (P < 0.05), but they had no significant correlation with clinical stage of CRC (P > 0.05).The mutation rates of EZH2 and VEGF genes in human CRC were 1.5% and 1.9%, respectively, and there were significant differences in the expression levels of EZH2 and VEGF mRNA in tissues with different EZH2 and VEGF mutation statuses. There are 22 proteins in the network. The average interaction index of each protein is 10.5, the regional aggregation index is 0.8, and the protein enrichment was obvious (P < 0.01). EZH2, DNMT1, HDAC2, YY1, and SUZ12 were screened as the key genes in the network using Cytohubb software. There was no correlation between the expression of EZH2 and VEGF and the total survival time of patients (P > 0.05), but the disease-free survival time of patients with high expression of VEGF was significantly lower than that of patients with low expression of VEGF (HR = 1.8, P < 0.05). Immunohistochemistry showed that the positive rates of EZH2 and VEGF proteins in CRC tissues were significantly higher than those in adjacent tissues (P < 0.01). The positive expression of EZH2 was related to tumor diameter, differentiation, and Duke stage (P < 0.05). The positive expression of VEGF was correlated with degree of differentiation and Duke stage (P < 0.05).

CONCLUSION

EZH2 and VEGF are up-regulated and mutated in CRC tissues. The high expression of EZH2 and VEGF is related to tumor size, differentiation, and Duke stage, and can be used as potential molecular markers for the prognosis of CRC.

Activation of the PI3K/Akt/mTOR/p70S6K pathway is involved in S100A4-induced viability and migration in colorectal cancer cells

The S100 protein family member S100A4 regulates various cellular functions. Previous studies have shown that elevated expression of S100A4 is associated with progression and metastasis of colorectal cancer (CRC). However, little is known about whether and how S100A4 contributes to CRC development. In our present study, the elevated expression of S100A4 in CRC tissues compared to matched adjacent normal tissues was confirmed by immunohistochemistry, semi-quantitative RT-PCR and Western blot. Adenovirus-mediated S100A4 overexpression obviously enhanced viability and migration of CRC cells, which was detected by MTT assay and transwell assay, respectively. Additionally, S100A4 overexpression increased the phosphorylation levels of Akt, mTOR and p70S6K. These effects of S100A4 were abolished by treatment with either the specific PI3K/Akt inhibitor LY294002, or the specific mTOR/p70S6K inhibitor rapamycin. Furthermore, overexpression of S100A4 resulted in upregulation of VEGF and downregulation of E-cadherin, which were strongly reversed by either LY294002 or rapamycin. Altogether, our results demonstrate that activation of the PI3K/Akt/mTOR/p70S6K signaling pathway is involved in S100A4-induced viability, migration, upregulation of VEGF and downregulation of E-cadherin in CRC cells.