Capn4 expression is modulated by microRNA-520b and exerts an oncogenic role in prostate cancer cells by promoting Wnt/β-catenin signaling.

Accumulating evidence reports that Capn4 plays an important role in the development and progression of various malignant cancers. However, whether Capn4 is involved in prostate cancer remains unclear. Therefore, the aim of this study was to investigate the expression, biological function and regulatory mechanism of Capn4 in prostate cancer. Herein, we found that Capn4 was highly expressed in prostate cancer cell lines compared with normal prostate cells. Capn4 gene silencing markedly suppressed the growth, invasion and Wnt/β-catenin signaling of prostate cancer cells, whereas Capn4 overexpression showed an oncogenic effect. Moreover, silencing of β-catenin significantly blocked the oncogenic effect of Capn4 overexpression. Bioinformatics analysis predicted that Capn4 was a potential target gene of microRNA-520b (miR-520b), which has been reported as a tumor suppressive miRNA in various cancers. The dual-luciferase reporter assay confirmed that miR-520b directly bound to the 3'-untranslated region of Capn4. Real-time quantitative PCR and Western blot analysis showed that miR-520b negatively regulated Capn4 expression in prostate cancer cells in vitro. Furthermore, we found that miR-520b was significantly downregulated in prostate cancer cell lines and tissues. In addition, miR-520b expression was inversely correlated with Capn4 expression in prostate cancer clinical specimens. Overexpression of miR-520b mimicked the tumor suppressive effect of Capn4 siRNA, whereas inhibition of miR-520b had an oncogenic effect. Restoration of Capn4 significantly blocked the antitumor effect of miR-520b in prostate cancer cells. Overall, our findings demonstrate an oncogenic role of Capn4 in prostate cancer and show that its expression is epigenetically regulated by miR-520b. Our results reveal that suppression of Capn4 by miR-520b inhibits the growth and invasion of prostate cancer cells associated with downregulated Wnt/β-catenin signaling, indicating an important role of the miR-520b/Capn4/Wnt/β-catenin regulation axis in the molecular pathogenesis of prostate cancer. Our study suggests that miR-520b and Capn4 may represent potential and novel therapeutic targets for prostate cancer.

Ren W ，Wang D ，Li C ，Shu T ，Zhang W ，Fu X ... -  《-》

MicroRNA-504 functions as a tumor suppressor in hepatocellular carcinoma through inhibiting Frizzled-7-mediated-Wnt/β-catenin signaling.

Accumulating evidence suggests that microRNAs (miRNAs) are critical regulators in the development and progression of various malignant tumors, including hepatocellular carcinoma (HCC). Multiple findings have indicated that miRNA-504 (miR-504) is dysregulated in several types of cancers, functioning as an oncogenic miRNA or a tumor suppressive miRNA. However, the role of miR-504 in HCC remains unknown. In this study, we aimed to detect the expression pattern of miR-504 in HCC tissues and cell lines and investigate the precise biological function in HCC cells. Our results showed that miR-504 expression levels were frequently downregulated in both HCC tissues and cell lines. Gain-of-function experiments demonstrated that miR-504 overexpression inhibited the proliferation and invasion in HCC cell lines. By contrast, miR-504 inhibition had the opposite effect. Interestingly, bioinformatics analysis predicted that Frizzled-7 (FZD7) was a potential target gene of miR-504. Dual-luciferase reporter assays confirmed that miR-504 directly targeted the 3'-untranslated region of FZD7 mRNA. In addition, our results showed that miR-504 negatively regulated the mRNA and protein expression of FZD7 in HCC cell lines. Moreover, miR-540 overexpression inhibited the cellular expression of β-catenin and blocked the activation of Wnt signaling in HCC cells. Notably, restoration of FZD7 expression significantly reversed the inhibitory effect of miR-504 on proliferation, invasion, and Wnt/β-catenin signaling in HCC cells. In conclusion, our results demonstrate that miR-504 functions as a tumor suppressive miRNA that inhibits the proliferation and invasion of HCC cells by targeting FZD7 and inhibiting Wnt/β-catenin signaling. Our study provides evidence that miR-504-meidated FZD7/Wnt/β-catenin signaling pathway plays an important role in HCC development and progression and suggests miR-504 as a novel future therapeutic target for treatment of HCC.

Quan H ，Li B ，Yang J 《-》

SOX30, a target gene of miR-653-5p, represses the proliferation and invasion of prostate cancer cells through inhibition of Wnt/β-catenin signaling.

Sex-determining region Y-box containing gene 30 (SOX30) is a newly identified tumor-associated gene in several types of cancer. However, whether SOX30 is involved in the development and progression of prostate cancer remains unknown. This study investigated the potential role of SOX30 in prostate cancer. Prostate cancer cell lines and a normal prostate epithelial cell line were used for the experiments. The expression of SOX30 was determined using quantitative real-time PCR and western blot analysis. The malignant cellular behaviors of prostate cancer were assessed using the Cell Counting Kit-8, colony formation and Matrigel invasion assays. The miRNA-mRNA interaction was validated using the dual-luciferase reporter assay. SOX30 expression was lower in cells of prostate cancer lines than in cells of the normal prostate epithelial line. Its overexpression repressed the proliferation and invasion of prostate cancer cells. SOX30 was identified as a target gene of microRNA-653-5p (miR-653-5p), which is upregulated in prostate cancer tissues. MiR-653-5p overexpression decreased SOX30 expression, while its inhibition increased SOX30 expression in prostate cancer cells. MiR-653-5p inhibition also markedly restricted prostate cancer cell proliferation and invasion. SOX30 overexpression or miR-653-5p inhibition significantly reduced β-catenin expression and downregulated the activation of Wnt/β-catenin signaling. SOX30 knockdown significantly reversed the miR-653-5p inhibition-mediated inhibitory effect on the proliferation, invasion and Wnt/β-catenin signaling in prostate cancer cells. These results reveal a tumor suppressive function for SOX30 in prostate cancer and confirmed the gene as a target of miR-653-5p. SOX30 upregulation due to miR-653-5p inhibition restricted the proliferation and invasion of prostate cancer cells, and this was associated with Wnt/β-catenin signaling suppression. These findings highlight the importance of the miR-653-5p-SOX30-Wnt/β-catenin signaling axis in prostate cancer progression.

Fu Q ，Sun Z ，Yang F ，Mao T ，Gao Y ，Wang H ... -  《-》

Suppression of microRNA-454 impedes the proliferation and invasion of prostate cancer cells by promoting N-myc downstream-regulated gene 2 and inhibiting WNT/β-catenin signaling.

MicroRNA-454 (miR-454) is emerging as critical regulator in tumorigenesis; it may function as an oncogene or a tumor suppressor. However, the role of miR-454 in prostate cancer remains unknown. In this study, we aimed to investigate the function and molecular mechanisms of miR-454 in prostate cancer. We found that miR-454 was highly expressed in prostate cancer tissues and cell lines (*p<0.05), as detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 assay, colony formation assay and cell invasion assay showed that the inhibition of miR-454 significantly suppressed prostate cancer cell proliferation and invasion (*p<0.05), whereas the overexpression of miR-454 markedly promoted prostate cancer cell proliferation and invasion (*p<0.05). Bioinformatics analysis showed that N-myc downstream-regulated gene 2 (NDRG2), a well-known tumor suppressor, was identified as a potential target gene of miR-454. Dual-luciferase reporter assay showed that miR-454 directly targeted the 3'-untranslated region of NDRG2. RT-qPCR and western blot showed that miR-454 overexpression significantly decreased NDRG2 expression (*p<0.05), whereas miR-454 inhibition markedly promoted NDRG2 expression (*p<0.05). Spearman's correlation analysis showed that miR-454 expression was inversely correlated with NDRG2 expression in prostate cancer tissues (r=-0.8932; p<0.0001). Moreover, miR-454 inhibition significantly suppressed the protein expression of β-catenin (*p<0.05) and blocked the activation of WNT signaling (*p<0.05). In addition, small interfering RNA mediated NDRG2 knockdown significantly reversed the antitumor effect of miR-454 inhibition on prostate cancer cell proliferation and invasion (*p<0.05). Taken together, these results reveal an oncogenic role of miR-454, which promotes prostate cancer cell proliferation and invasion by downregulation of NDRG2. These results also suggest miR-454 as a potential therapeutic target for the treatment of prostate cancer.

Fu Q ，Gao Y ，Yang F ，Mao T ，Sun Z ，Wang H ，Song B ，Li X ... -  《-》

Suppression of Capn4 by microRNA-1271 impedes the proliferation and invasion of colorectal cancer cells.

Accumulating evidence has suggested that calpain small subunit 1 (Capn4) plays an important role in the development and progression of malignant tumors. However, little is known about the role of Capn4 in colorectal cancer (CRC). In this study, we aimed to investigate the potential role of Capn4 in CRC and the regulation of Capn4 by microRNAs (miRNAs). Here, we found that Capn4 expression was highly up-regulated in CRC cell lines. Knockdown of Capn4 by siRNA significantly inhibited the proliferation and invasion of CRC cell lines. Furthermore, knockdown of Capn4 suppressed Wnt signaling in CRC cells. Interestingly, Capn4 was found to be a target gene of miR-1271, a tumor suppressive miRNA. The results showed that miR-1271 negatively regulated Capn4 expression in CRC cells. An inverse correlation between miR-1271 and Capn4 was also shown in CRC clinical tissues. Moreover, the overexpression of miR-1271 suppressed the proliferation, invasion and Wnt signaling of CRC cells. Importantly, we found that the restoration of Capn4 expression significantly reversed the antitumor effects of miR-1271 in CRC cells. Overall, these results suggest that miR-1271 inhibits the proliferation and invasion of CRC cells by down-regulating Capn4. Our study suggests that Capn4 and miR-1271 may serve as potential therapeutic targets for the treatment of CRC.

Li J ，Xu J ，Yan X ，Jin K ，Li W ，Zhang R ... -  《-》