Our previous studies have shown that the 3' end of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) is involved in colorectal cancer (CRC) cell proliferation and migration/invasion in vitro. The role and mechanism of MALAT1 in CRC metastasis in vivo, however, remain largely unknown. In the present study, we found that MALAT1 was up-regulated in human primary CRC tissues with lymph node metastasis. Overexpression of MALAT1 via RNA activation promoted CRC cell proliferation, invasion and migration in vitro, and stimulated tumor growth and metastasis in mice in vivo. Conversely, knockdown of MALAT1 inhibited CRC tumor growth and metastasis. MALAT1 regulated at least 243 genes in CRC cells in a genome-wide expression profiling. Among these genes, PRKA kinase anchor protein 9 (AKAP-9) was significantly up-regulated at both mRNA and protein levels. AKAP-9 was highly expressed in CRC cells with metastatic potential and human primary CRC tissues with lymph node metastasis, but not in normal cells or tissues. Importantly, knockdown of AKAP-9 blocked MALAT1-mediated CRC cell proliferation, migration and invasion. These data indicate that MALAT1 may promote CRC tumor development via its target protein AKAP-9.

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BackgroundAccumulating evidence indicates that CD36 initiates metastasis and correlates with an unfavorable prognosis in cancers. However, there are few reports regarding the roles of CD36 in initiation and metastasis of cervical cancer.MethodsUsing immunohistochemistry, we analyzed 133 cervical cancer samples for CD36 protein expression levels, and then investigated the correlation between changes in its expression and clinicopathologic parameters. The effect of CD36 expression on the epithelial–mesenchymal transition (EMT) in cervical cancer cells was evaluated by Western immunoblotting analysis. In vitro invasion and in vivo metastasis assays were also used to evaluate the role of CD36 in cervical cancer metastasis.ResultsIn the present study, we confirmed that CD36 was highly expressed in cervical cancer samples relative to normal cervical tissues. Moreover, overexpression of CD36 promoted invasiveness and metastasis of cervical cancer cells in vitro and in vivo, while CD36 knockdown suppressed proliferation, migration, and invasiveness. We demonstrated that TGF-β treatment attenuated E-cadherin expression and enhanced the expression levels of CD36, vimentin, slug, snail, and twist in si-SiHa, si-HeLa, and C33a–CD36 cells, suggesting that TGF-β synergized with CD36 on EMT via active CD36 expression. We also observed that the expression levels of TGF-β in si-SiHa cells and si-HeLa cells were down-regulated, whereas the expression levels of TGF-β were up-regulated in C33a–CD36 cells. These results imply that CD36 and TGF-β interact with each other to promote the EMT in cervical cancer.ConclusionsOur findings suggest that CD36 is likely to be an effective target for guiding individualized clinical therapy of cervical cancer.

Our previous studies have shown that PRKA kinase anchor protein 9 (AKAP-9) is involved in colorectal cancer (CRC) cell proliferation and migration in vitro. However, whether or not AKAP-9 is important for CRC development or metastasis in vivo remains unknown. In the present study, we found that AKAP-9 expression was significantly higher in human colorectal cancer tissues than the paired normal tissues. In fact, AKAP-9 level correlated with the CRC infiltrating depth and metastasis. Moreover, the higher AKAP-9 expression was associated with the lower survival rate in patients. In cultured CRC cells, knockdown of AKAP-9 inhibited cell proliferation, invasion, and migration. AKAP-9 deficiency also attenuated CRC tumor growth and metastasis in vivo. Mechanistically, AKAP-9 interacted with cdc42 interacting protein 4 (CIP4) and regulated its expression. CIP4 levels were interrelated to the AKAP-9 level in CRC cells. Functionally, AKAP-9 was essential for TGF-β1-induced epithelial-mesenchymal transition of CRC cells, and CIP4 played a critical role in mediating the function of AKAP-9. Importantly, CIP4 expression was significantly up-regulated in human CRC tissues. Taken together, our results demonstrated that AKAP-9 facilitates CRC development and metastasis via regulating CIP4-mediated epithelial-mesenchymal transition of CRC cells.