Xiaodi Zhao

MicroRNA Let-7f Inhibits Tumor Invasion and Metastasis by Targeting MYH9 in Human Gastric Cancer

Background MicroRNAs (miRNAs) are important regulators that play key roles in tumorigenesis and tumor progression. A previous report has shown that let-7 family members can act as tumor suppressors in many cancers. Through miRNA array, we found that let-7f was downregulated in the highly metastatic potential gastric cancer cell lines GC9811-P and SGC7901-M, when compared with their parental cell lines, GC9811 and SGC7901-NM; however, the mechanism was not clear. In this study, we investigate whether let-7f acts as a tumor suppressor to inhibit invasion and metastasis in gastric cancers. Methodology/Principal Real-time PCR showed decreased levels of let-7f expression in metastatic gastric cancer tissues and cell lines that are potentially highly metastatic. Cell invasion and migration were significantly impaired in GC9811-P and SGC7901-M cell lines after transfection with let-7f-mimics. Nude mice with xenograft models of gastric cancer confirmed that let-7f could inhibit gastric cancer metastasis in vivo after transfection by the lentivirus pGCsil-GFP- let-7f. Luciferase reporter assays demonstrated that let-7f directly binds to the 3′UTR of MYH9, which codes for myosin IIA, and real-time PCR and Western blotting further indicated that let-7f downregulated the expression of myosin IIA at the mRNA and protein levels. Conclusions/Significance Our study demonstrated that overexpression of let-7f in gastric cancer could inhibit invasion and migration of gastric cancer cells through directly targeting the tumor metastasis-associated gene MYH9. These data suggest that let-7f may be a novel therapeutic candidate for gastric cancer, given its ability to reduce cell invasion and metastasis.

Gankyrin promotes the proliferation of human pancreatic cancer

Previous studies in our laboratory have suggested that gankyrin expression is correlated with a malignant phenotype in colorectal cancer. Here, we investigated the possible role of gankyrin in pancreatic carcinogenesis. Gankyrin expression was significantly increased in pancreatic cancer compared to non-cancerous tissues. This expression significantly enhanced cancer cell proliferation and growth in vitro and in vivo. Suppression of gankyrin downregulated cyclin A, cyclin D1, cyclin E, CDK2, CDK4, PCNA and p-Rb but upregulated p27, Rb and p53. However, gankyrin overexpression led to opposite results. Thus, gankyrin could enhance pancreatic cancer cell proliferation by promoting cell cycle progression and p53 degradation.

miR-143 and miR-145 inhibit gastric cancer cell migration and metastasis by suppressing MYO6

Metastasis is a major clinical obstacle responsible for the high mortality and poor prognosis of gastric cancer (GC). MicroRNAs (miRNAs) are critical mediators of metastasis that act by modulating their target genes. In this study, we found that miR-143 and miR-145 act via a common target gene, MYO6, to regulate the epithelial–mesenchymal transition (EMT) and inhibit metastasis. We determined that miR-143 and miR-145 were downregulated in GC, and the ectopic expression of miR-143 and/or miR-145 inhibited GC cell migration and metastasis. Furthermore, MYO6 was identified as a direct common target of miR-143 and miR-145 and was elevated in GC. Silencing of MYO6 resulted in a metastasis-suppressive activity similar to that of miR-143 and miR-145, while restoring MYO6 attenuated the anti-metastatic or anti-EMT effects caused by miR-143 and miR-145. Clinically, an inverse correlation was observed between miR-143/145 levels and MYO6 levels in GC tissues, and either miR-143/145 downregulation or MYO6 upregulation was associated with more malignant phenotypes in patients with GC. In conclusion, miR-143 and miR-145 suppress GC cell migration and metastasis by inhibiting MYO6 expression and the EMT, which provides a novel mechanism and promising therapeutic target for the treatment of GC metastasis.

MicroRNAs as critical regulators involved in regulating epithelial- mesenchymal transition.

The epithelial-mesenchymal transition (EMT) is a fundamental biological process that is involved in normal embryogenesis, would healing, and tissue repair, as well as numerous pathologies, including organ fibrosis, malignant transformation, and cancer progression. Both transcriptional and post-transcriptional regulatory mechanisms contribute to a complex and tightly controlled regulatory network during the EMT process, and a growing body of evidence now demonstrates that microRNAs (miRNAs) are crucial regulators of this network. miRNAs are a class of small non-coding RNAs that regulate gene expression through translational repression or mRNA degradation. A set of miRNAs have been discovered that have the potential to target multiple components of the signaling pathways and downstream effectors of the EMT. Our understanding of the roles that miRNAs play during the EMT process suggests that these miRNAs may eventually serve as novel biomarkers and therapeutic targets for various EMT-based pathological conditions. This review summarizes the current knowledge concerning how miRNAs mechanistically regulate the EMT and discusses the specific roles that miRNAs play in three EMT subtypes. We hope that a more comprehensive understanding of the functions of miRNAs in the EMT process will lead to the rapid development of novel diagnostic techniques and molecular-based strategies for controlling EMT.

Ran GTPase protein promotes human pancreatic cancer proliferation by deregulating the expression of Survivin and cell cycle proteins.

Ran, a member of the Ras GTPase family, has important roles in nucleocytoplasmic transport. Herein, we detected Ran expression in pancreatic cancer and explored its potential role on tumour progression. Overexpressed Ran in pancreatic cancer tissues was found highly correlated with the histological grade. Downregulation of Ran led to significant suppression of cell proliferation, cell cycle arrest at the G1/S phase and induction of apoptosis. In vivo studies also validated that result. Further studies revealed that those effects were at least partly mediated by the downregulation of Cyclin A, Cyclin D1, Cyclin E, CDK2, CDK4, phospho-Rb and Survivin proteins and up regulation of cleaved Caspase-3.

Loss of vinculin and membrane-bound β-catenin promotes metastasis and predicts poor prognosis in colorectal cancer

BackgroundLoss of cell-cell adhesion is important for the development of cancer invasion and metastasis. Vinculin, a key adhesion-related protein, can affect metastasis and prognosis in several tumours. Here, we determined the biological roles of vinculin in the metastasis of colorectal cancer (CRC) and evaluated its clinical significance as a potential disease biomarker.MethodsThe expression level of vinculin in CRC cell lines and tissues was measured using Real-Time PCR and western blotting. Moreover, vinculin function was analysed using Transwell assays and in vivo metastasis assays in gain- and loss-of-function experiments. Furthermore, the impact of vinculin together with membrane-bound β-catenin on the prognosis of 228 CRC patients was investigated by immunohistochemistry. Additionally, the expression of epithelial-mesenchymal transition (EMT) indicators was verified by immunohistochemistry in CRC tissues obtained from these patients.ResultVinculin expression was found to be significantly downregulated in highly metastatic CRC cell lines and metastatic tissues. Both in vitro and in vivo experiments showed that vinculin suppressed invasion, migration and metastasis in CRC cells and that this suppression could be attenuated by silencing β-catenin. Moreover, the expression of vinculin and membrane-bound β-catenin were positively correlated in CRC tissues, and lack of vinculin expression emerged as an independent prognostic factor in patients with CRC. Finally, the loss of vinculin and membrane-bound β-catenin was associated with node metastasis, organ metastasis and expression of EMT indicators.ConclusionOur results suggest that vinculin may play specific roles in the EMT and metastasis of CRC and that loss of vinculin could be used as a prognostic factor for CRC.

Thioredoxin-Like Protein 2 Is Overexpressed in Colon Cancer and Promotes Cancer Cell Metastasis by Interaction with Ran

AIMS Our previous work identified thioredoxin-like protein 2 (Txl-2) as the target of the monoclonal antibody MC3 associated with colon cancer, but its underlying mechanisms remain poorly understood. Txl-2, a novel thioredoxin (Trx) and nucleoside diphosphate kinase family member, is alternatively spliced and gives rise to three different Txl-2 isoforms. In this study, Txl-2 expression in colon cancer, differential functions for Txl-2 isoforms in cell invasion and metastasis, and the downstream signaling were investigated. RESULTS Txl-2 expression was elevated in colon cancer tissues compared to normal colonic tissues, with a high correlation between the histological grade and prognosis. Knockdown of Txl-2 expression significantly inhibited cancer cell motility, and the invasive and metastatic abilities of colon cancer cells. Interestingly, Txl-2 isoforms showed differential effects on cancer cell invasion and metastasis. Cell invasion and metastasis were significantly promoted by Txl-2b but inhibited by Txl-2c, while no obvious effect was observed for Txl-2a. Furthermore, a direct interaction was identified between Txl-2b and Ran, a Ras-related protein, by yeast two-hybrid assay and coimmunoprecipitation. PI3K pathway was found to be a major pathway mediating Txl-2b induced tumor invasion and metastasis. INNOVATION The current study provides a novel biomarker and target molecule for the diagnosis and treatment of colon cancer and provides a novel paradigm to understand how alternative splicing functions in human cancer. CONCLUSION Our findings demonstrate an elevated Txl-2 expression in colon cancer and that Txl-2b promotes cell invasion and metastasis through interaction with Ran and PI3K signaling pathway.

RUNX3 Mediates Suppression of Tumor Growth and Metastasis of Human CCRCC by Regulating Cyclin Related Proteins and TIMP-1

Here we presented that the expression of RUNX3 was significantly decreased in 75 cases of clear cell renal cell carcinoma (CCRCC) tissues (p<0.05). Enforced RUNX3 expression mediated 786-O cells to exhibit inhibition of growth, G1 cell-cycle arrest and metastasis in vitro, and to lost tumorigenicity in nude mouse model in vivo. RUNX3-induced growth suppression was found partially to regulate various proteins, including inhibition of cyclinD1, cyclinE, cdk2, cdk4 and p-Rb, but increase of p27Kip1, Rb and TIMP-1. Therefore, RUNX3 had the function of inhibiting the proliferative and metastatic abilities of CCRCC cells by regulating cyclins and TIMP1.

Thioredoxin-like protein 2b facilitates colon cancer cell proliferation and inhibits apoptosis via NF-κB pathway

Our previous work identified thioredoxin-like protein 2 (Txl-2), a novel thioredoxin family member, as the target of the monoclonal antibody MC3 which can detect colon cancer with high sensitivity and specificity. In the present study, the function of the most abundant isoform Txl-2b in cell proliferation and apoptosis was investigated. Txl-2 overexpression correlated with increased clinical stages. Inhibition of Txl-2b suppressed cell proliferation, induced cell cycle arrest at the G1/S phase, and led to responsiveness to the vincristine-induced apoptosis in SW620 cells. Txl-2b overexpression in LoVo cells had the opposite effect, which was dependent on Trx domain function. In vivo studies validated that Txl-2b expression promoted colon cancer tumorigenesis in nude mice. Further studies revealed that nuclear factor-κB (NF-κB) signaling was activated by Txl-2b. Inhibition of NF-κB activation partly abrogated the pro-proliferation and anti-apoptotic phenotypes mediated by Txl-2b via reduced Cyclin D1, Bcl-2, Bcl-xL and Survivin expression and increased Caspase-3 activation. Overall, our results indicate that Txl-2b expression stimulates cancer cell proliferation, accelerates the cell cycle and contributes to apoptosis resistance in colon cancer and provides a potential therapeutic target for colon cancer treatment.

MiR-2392 suppresses metastasis and epithelial–mesenchymal transition by targeting MAML3 and WHSC1 in gastric cancer

MicroRNAs have emerged as essential regulators of various cellular processes. We identified the role and underlying mechanisms of miR‐2392 in gastric cancer (GC) metastasis. MiR‐2392 was down‐regulated in GC cell lines and tissues, and overexpression of miR‐2392 significantly inhibited GC invasion and metastasis in vitro and in vivo. We identified MAML3 and WHSC1 as novel targets of miR‐2392, and knockdown of MAML3 and WHSC1 had the same antimetastatic effect as that of miR‐2392 in GC cells. These effects were clinically relevant, as low miR‐2392 expression was correlated with high MAML3 and WHSC1 expression and poor survival in patients with GC. Furthermore, forced expression of miR‐2392 substantially suppressed Slug and Twist1, transcriptional repressors of E‐cadherin, by targeting MAML3 and WHSC1, respectively, resulting in inhibition of the epithelial–mesenchymal transition. These findings indicate that the miR‐2392–MAML3/WHSC1–Slug/Twist1 regulatory axis plays a critical role in GC metastasis. Restoration of miR‐2392 may be a therapeutic approach for blocking GC metastasis.—Li, J., Li, T., Lu, Y., Shen, G., Guo, H., Wu, J., Lei, C., Du, F., Zhou, F., Zhao, X., Nie, Y., Fan, D. MiR‐2392 suppresses metastasis and epithelial–mesenchymal transition by targeting MAML3 and WHSC1 in gastric cancer. FASEB J. 31, 3774–3786 (2017). www.fasebj.org—Branco, Renato Chaves Souto, Camargo, Rafael Ludemann, Batista, Thiago Martins, Vettorazzi, Jean Franciesco, Borck, Patricia Cristine, dos Santos‐Silva, Junia Carolina Rebelo, Boschero, Antonio Carlos, Zoppi, Claudio Cesar, Carneiro, Everardo Magalhäes MiR‐2392 suppresses metastasis and epithelial–mesenchymal transition by targeting MAML3 and WHSC1 in gastric cancer. FASEB J. 31, 3774–3786 (2017)