MiR-199a/b-3p suppresses migration and invasion of breast cancer cells by downregulating PAK4/MEK/ERK signaling pathway.

MicroRNA-199a/b-3p is downregulated in several types of aggressive cancer, and its decrement significantly correlates with poor survival. Here, we aim to investigate the biological function of miR-199a/b-3p and its regulation of target genes in breast cancer cells with highly metastatic potential. In addition, we found that miR-199a/b-3p expression was much lower in MDA-MB-231, CAL120, and HCC1395 breast cancer cells with highly metastatic potential. Functional assays showed that restored miR-199a/b-3p expression inhibited MDA-MB-231 cell growth, cell-cycle progression, migration, and invasion. In addition, we experimentally demonstrated that PAK4 was the direct target of miR-199a/b-3p, hypo-expression of PAK4 suppressed proliferation, migration and invasion of MDA-MB-231 cells, and overexpression of PAK4 significantly rescued the inhibitory effect of miR-199a/b-3p on MDA-MB-231 cell growth, migration, and invasion. Further, we also observed that miR-199a/b-3p could inactivate the PAK4/MEK/ERK signaling pathway. Thus, miR-199a/b-3p functions as a tumor suppressor and has an important role in breast cancer metastasis through PAK4/MEK/ERK signaling pathway.

Li SQ ，Wang ZH ，Mi XG ，Liu L ，Tan Y ... -  《-》

MiR-199a/b-3p inhibits gastric cancer cell proliferation via down-regulating PAK4/MEK/ERK signaling pathway.

Zeng B ，Shi W ，Tan G 《BMC CANCER》

NLK, a novel target of miR-199a-3p, functions as a tumor suppressor in colorectal cancer.

We previously reported that miR-199a-3p is a newly biomarker for diagnosis and novel prognostic indicator in colorectal cancer. However, the miR-199a-3p regulatory mechanism and its target genes are still unclear. In our present study, we demonstrated miR-199a-3p could directly target 3'-UTR of NLK gene by luciferase reporter assay and western blot analysis. We detected NLK expressions in 92 colorectal cancer cases to evaluate its clinicopathologic characteristics in colorectal cancer. Our results showed that NLK expression was significantly downregulated in cancer tissues than NATs, and NLK low-expression was associated with lymph node metastasis, venous invasion, liver metastasis and the TNM stage (P<0.05). Moreover, Kaplan-Meier analysis showed that low expression of NLK correlated with a shorter overall survival rates of patients with CRC (P<0.05). In vitro, we also found that NLK suppressed the biological behaviors of colorectal cancer cells, including the abilities of cell proliferation, clone formation, wound healing, migration and invasion (P<0.05), while overexpression of NLK increased the apoptotic rate of colorectal cancer cells. All these results suggested that NLK was an identified miR-199a-3p target gene and functioned as a tumor suppressor gene in colorectal cancer. NLK could be a novel direction for developing diagnostic and therapeutic approaches in colorectal cancer.

Han Y ，Kuang Y ，Xue X ，Guo X ，Li P ，Wang X ，Guo X ，Yuan B ，Zhi Q ，Zhao H ... -  《-》

MiR-199a/b-3p inhibits colorectal cancer cell proliferation, migration and invasion through targeting PAK4 and BCAR3.

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. P21 activated kinase 4 (PAK4) and Breast cancer anti-estrogen resistance 3 (BCAR3) have been reported to be involved in numerous aspects in tumorous progression. In this study, we propose to screen multi-targeted microRNAs. (miRNAs), which simultaneously inhibit neoplastic evolution through suppressing the transcription of target genes. MTT and Colony formation assays measured cell's viability and proliferation. Scratch wound and Transwell assays detected the ability in migration and invasion for SW116 cells. The multi-targeted microRNAs of PAK4 and BCAR3 were predicted using bioinformatics analysis and verified by conducting dual luciferase reporter assay, western blot and qRT-PCR that could detect the expression levels of miR-199a/b-3p. The knockdown of PAK4 significantly impeded proliferation and colony formation of SW1116 cells when the knockdown of BCAR3 hindered migration and invasion of SW1116 cells. MiR-199a/b-3p directly targeted the 3'-UTR of PAK4 and BCAR3, further effected proliferation, colony formation, migration, and invasion of SW1116 cells. PAK4 or BCAR3 overexpression could partially reversed inhibitory effects of miR-199a/b-3p. These results provided a new multi-targeted cite for cancerous suppressant to improve the prognosis of CRC inpatients.

Hou J ，Mi X ，Liu N ，Li X ，Li XN ，Yang Y ，Lu X ，Fang Y ，Jin NY ... -  《-》

MicroRNA-409-3p regulates cell invasion and metastasis by targeting ZEB1 in breast cancer.

MicroRNA-409-3p (miR-409-3p) is an miRNA expressed by embryonic stem cells, and our previous study demonstrated depressed miR-409-3p expression in human breast cancer (BC) cell lines; however, its role and function in BC metastasis are still unknown. The purpose of this study was to examine the expression levels of miR-409-3p in human BC and its role in the metastasis of BC. We analyzed the status of miR-409-3p expression in BC tissues by quantitative real-time polymerase chain reaction (PCR) and its relationship to the clinicopathologic features of patients with BC. To study the role of miR-409-3p in BC metastasis, the invasion ability of BC cells was detected by transwell invasion assays and wound healing assays. WST-1 assays and colony formation assays were used to investigate cell proliferation. Luciferase reporter assays were used to verify that miR-409-3p targeted zinc-finger E-box-binding homeobox 1 (ZEB1). Western blot analyses and transwell assays were carried out to assess ZEB1 expression and its role in BC cell metastasis. The expression of miR-409-3p was lower in tumor tissues than in noncancerous breast tissues. We verified that miR-409-3p levels were downregulated and significantly correlated with poor outcomes in patients with BC. Overexpression of miR-409-3p inhibited cellular proliferation and suppressed cellular migration and invasion in vitro and in vivo. Dual-luciferase reporter assays showed that miR-409-3p binds the 3'-untranslated region (3'-UTR) of ZEB1, suggesting that ZEB1 is a direct target of miR-409-3p. Western blot analysis confirmed that overexpression of miR-409-3p reduced ZEB1 protein levels. These data demonstrate that miR-409-3p plays an important role in regulating the metastasis of BC, which is involved in the post-transcriptional repression of ZEB1. Our results indicate that miR-409-3p can regulate the invasion and metastasis process of BC by targeting ZEB1 and may serve as a new prognostic marker and therapeutic target for treating BC metastasis. © 2016 IUBMB Life, 68(5):394-402, 2016.

Ma Z ，Li Y ，Xu J ，Ren Q ，Yao J ，Tian X ... -  《-》