Bladder cancer causes an estimated 150,000 deaths per year worldwide. Although 15% of the recurrent bladder cancer becomes an invasive type, currently used targeted therapy for malignant bladder cancer is still not efficient. We focused on the miR-130 family (miR-130b, miR-301a and miR-301b) that was significantly upregulated in bladder cancer specimens than that of the normal urothelial specimens. We analyzed the functional significance of miR-130 family using a 5637 bladder cancer cell line and revealed that miR-130 family of inhibitors suppressed cell migration and invasion by downregulating focal adhesion kinase (FAK) and Akt phosphorylation. Mechanistic analyses indicate that the miR-130 family directly targets phosphatase and tensin homolog deleted from chromosome 10 (PTEN), resulting in the upregulation of FAK and Akt phosphorylation. In clinical bladder cancer specimens, downregulation of PTEN was found to be closely correlated with miR-130 family expression levels. Overall, the miR-130 family has a crucial role in malignant progression of bladder cancer and thus the miR-130 family could be a promising therapeutic target for invasive bladder cancer.

Renal cell carcinoma (RCC) is the most common neoplasm of the adult kidney, and clear cell RCC (ccRCC) represents its most common histological subtype. To identify a therapeutic target for ccRCC, miRNA expression signatures from ccRCC clinical specimens were analyzed. miRNA microarray and real-time PCR analyses revealed that miR-629 expression was significantly upregulated in human ccRCC compared with adjacent noncancerous renal tissue. Functional inhibition of miR-629 by a hairpin miRNA inhibitor suppressed ccRCC cell motility and invasion. Mechanistically, miR-629 directly targeted tripartite motif-containing 33 (TRIM33), which inhibits the TGFβ/Smad signaling pathway. In clinical ccRCC specimens, downregulation of TRIM33 was observed with the association of both pathologic stages and grades. The miR-629 inhibitor significantly suppressed TGFβ-induced Smad activation by upregulating TRIM33 expression and subsequently inhibited the association of Smad2/3 and Smad4. Moreover, a miR-629 mimic enhanced the effect of TGFβ on the expression of epithelial–mesenchymal transition–related factors as well as on the motility and invasion in ccRCC cells. These findings identify miR-629 as a potent regulator of the TGFβ/Smad signaling pathway via TRIM33 in ccRCC. Implications: This study suggests that miR-629 has biomarker potential through its ability to regulate TGFβ/Smad signaling and accelerate ccRCC cell motility and invasion. Mol Cancer Res; 13(3); 565–74. ©2014 AACR.

Clear cell renal cell carcinoma (ccRCC) is the most common histologically defined subtype of renal cell carcinoma (RCC). To define the molecular mechanism in the progression of ccRCC, we focused on LOX-like protein 2 (LOXL2), which is critical for the first step in collagen and elastin cross-linking. Using exon array analysis and quantitative validation, LOXL2 was shown to be significantly upregulated in clinical specimens of human ccRCC tumor tissues, compared with adjacent noncancerous renal tissues, and this elevated expression correlated with the pathologic stages of ccRCC. RNAi-mediated knockdown of LOXL2 resulted in marked suppression of stress-fiber and focal adhesion formation in ccRCC cells. Moreover, LOXL2 siRNA knockdown significantly inhibited cell growth, migration, and invasion. Mechanistically, LOXL2 regulated the degradation of both integrins α5 (ITGAV5) and β1 (ITGB1) via protease- and proteasome-dependent systems. In clinical ccRCC specimens, the expression levels of LOXL2 and integrin α5 correlated with the pathologic tumor grades. In conclusion, LOXL2 is a potent regulator of integrin α5 and integrin β1 protein levels and functions in a tumor-promoting capacity in ccRCC. Implications: This is the first report demonstrating that LOXL2 is highly expressed and involved in ccRCC progression by regulating the levels of integrins α5 and β1. Mol Cancer Res; 12(12); 1807–17. ©2014 AACR.

Extracellular matrix metalloproteinase inducer (EMMPRIN) has been reported to play crucial roles, including in angiogenesis, in several carcinomas. However, the correlation between EMMPRIN levels and angiogenesis expression profile has not been reported, and the role of EMMPRIN in renal cell carcinoma (RCC) is unclear. In the present study, we evaluated the association of EMMPRIN with angiogenesis, its value in prognosis, and its roles in RCC. EMMPRIN expression was examined in 50 RCC patients treated with radical nephrectomy. Angiogenesis, proliferation, and invasion activity were evaluated using EMMPRIN knockdown RCC cell lines. The size of EMMPRIN-overexpressing xenografts was measured and the degree of angiogenesis was quantified. EMMPRIN expression was evaluated in RCC patients who received sunitinib therapy and in sunitinib-resistant cells. Further, the relation between EMMPRIN expression and sensitivity to sunitinib was examined. EMMPRIN score was significantly associated with clinicopathological parameters in RCC patients, as well as being significantly correlated with microvessel area (MVA) in immature vessels and with prognosis. Down-regulation of EMMPRIN by siRNA led to decreased VEGF and bFGF expression, cell proliferation, and invasive potential. EMMPRIN over-expressing xenografts showed accelerated growth and MVA of immature vessels. EMMPRIN expression was significantly increased in patients who received sunitinib therapy as well as in sunitinib-resistant 786-O cells (786-suni). EMMPRIN-overexpressing RCC cells were resistant to sunitinib. Our findings indicate that high expression of EMMPRIN in RCC plays important roles in tumor progression and sunitinib resistance. Therefore, EMMPRIN could be a novel target for the treatment of RCC.