RAP80 regulates epithelial-mesenchymal transition related with metastasis and malignancy of cancer.
Bottom Line: The downregulation of RAP80 increases ZEB1 protein and decreases miR200c expression to activate EMT signaling in the form of drastic inhibitions of E-cadherin, p16 and p21 expression.Using in vivo metastasis analysis, RAP80 knockdown cells are shown to dramatically metastasize into the lung and generate more malignant phenotype compared to controls.Interestingly, the expression level of RAP80 was positively correlated with the survival rate in lung adenocarcinoma and breast cancer patients.
Affiliation: Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, Korea.Show MeSH
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Mentions: To test malignancy of RAP80 knockdown HeLa cells, we i.v. injected control and RAP80 knockdown HeLa cells into Balb/C nude mice, killing mice at 1, 2, 7, 15 and 25 days after injection to analyze cancer malignancy in the lung. As shown in Figure 6(a), the lung of RAP80 knockdown cell‐injected mice showed increase in metastatic nodule number at 7, 14 and 25 days after injection and completely collapsed at 25 days after injection. Histological analysis (H&E staining) showed a large accumulation of non‐alveolar cells in alveoli structure at 1, 2, 7 and 14 days after injection of RAP80 knockdown cells, indicating that shRAP80‐2 cells accumulated in the lung (Fig. 6b). Importantly, the size and number of metastasized cancer nodules are greatly increased in the lung of shRAP80‐2‐injected mice (Fig. 6b). To consolidate the conclusion, we performed the same Xenograft experiment and periodically checked body weight for 15 days after injection. As shown in Figure 6(c), shRAP80‐2 injected mice showed significant decrease of body weight, indicating health problems. At 15 days after injection, all mice are killed for further analysis. As shown in Figure S2(a), shRAP80‐2‐injected mice showed a hunchback phenotype, indicating severe muscle weakness, probably due to cancer cachexia. For a statistical analysis of metastatic nodules, we dissected the lungs (Fig. S2b) and counted the number of metastatic nodules. As shown in Figure 6(c), the shRAP80‐2‐injected group showed a significant increase of metastatic nodules in the lung. Together, the downregulation of RAP80 induces metastasis and makes cancer cells more malignant.
Affiliation: Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, Korea.