10155

TRIM28

This study aimed to investigate the role in metastasis and prognostic value of KAP-1 in pancreatic cancer (PC). The expression of KAP-1 was analyzed by quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemical staining in 91 human PC tissue samples. Capan-2 cells were transfected with a lentiviral vector expressing KAP-1 (Capan-2/KAP-1) or the empty vector (Capan-2/vector); cell migration and invasion were assayed in vitro using Transwell migration and wound-healing assays, and in vivo using a xenograft model in nude mice. KAP-1 was found to be overexpressed in human PC, and the expression of KAP-1 correlated with clinical stage. Overexpression of KAP-1 increased the invasion and migration of Capan-2 cells in vitro. Furthermore, overexpression of KAP-1 promoted the growth and metastatic ability of PC cells in a xenograft model in nude mice. Moreover, overexpression of KAP-1 induced the epithelial-mesenchymal transition (EMT) in PC cells both in vitro and in vivo, as indicated by increased expression of mesenchymal markers such as vimentin and decreased expression of E-cadherin. This study indicates that KAP-1 may promote metastasis in PC by regulating the EMT and suggests that KAP-1 may have potential as a predictor of metastasis in patients with pancreatic cancer.

The prediction of who develops metastasis has been the most difficult aspect in the management of breast cancer patients. The lymph node metastasis has been the most useful predictor of prognosis and patient management. However, a good proportion of patients with lymph node positivity remain disease free for 5 years or more, while about a third of those who were lymph node negative develop distant metastasis within the same period. This warrants a robust biomarker(s), preferably gene expression based. In order to elucidate gene-based biomarkers for prognosis of breast cancers, gene expression profiling of primary tumors and follow-up for over 5 years has been performed. The analysis revealed a network of genes centered around the tripartite motif-containing protein 28 as an important indicator of disease progression. Short hairpin RNA-mediated knockdown of tripartite motif-containing protein 28 in breast cancer cells revealed a decreased expression of epithelial-to-mesenchymal transition markers and increased expression of epithelial markers, decreased migration and invasion, and increased chemosensitivity to doxorubicin, 5-fluorouracil, and methotrexate. Furthermore, knockdown of tripartite motif-containing protein 28 resulted in the decrease of stemness as revealed by sphere formation assay as well as decreased expression of CD44 and Bmi1. Moreover, tripartite motif-containing protein 28 knockdown significantly reduced the tumor size and lung metastasis in orthotopic tumor xenograft assay in immunocompromised mice. The tumor size was further reduced when these mice were treated with doxorubicin. These data provide evidence for tripartite motif-containing protein 28 as a biomarker and a potential therapeutic target for breast cancer.

Tripartite motif containing 28 (TRIM28) is a transcriptional corepressor of Kruppel-associated box zinc finger protein, which has been reported to participate in carcinogenesis. Nonetheless, whether TRIM28 plays a role in the metastasis of ovarian carcinoma (OC) is unclear and requires further investigation. In this study, two OC cell lines (A2780 and OVCAR-3) with stable low expression of TRIM28 were established via RNA interference. We found that the migratory and invasive ability of TRIM28-silenced OC cells significantly decreased. The expression and activity of matrix metallopeptidase (MMP)-2 and MMP-9 in these OC cells were inhibited. The TRIM28 shRNA also suppressed the epithelial-mesenchymal transition (EMT) of OC cells as evidenced by the up-regulated E-cadherin and the downregulated Vimentin and N-cadherin. Additionally, the Wnt/beta-catenin signaling pathway was suppressed in TRIM28-silenced OC cells: the activity of beta-catenin was inhibited, the expression of total and nuclear beta-catenin, Axin 2, T-cell factor 1 (TCF1) and lymphoid enhancer binding factor 1 (LEF1) were decreased, whereas the phosphorylation of beta-catenin at Ser33/37 was enhanced. Further, re-expression of active beta-catenin in TRIM28-silenced OC cells partly restored their metastasis in vitro. Taken together, our study demonstrates a contributory role of TRIM28 in OC metastasis in vitro, suggesting TRIM28 as a novel therapeutic target for this malignant tumor.