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Background:MiR-646 has been reported to be aberrantly expressed in human cancers. However, the underlying molecular mechanisms of action of miR-646 in gastric cancer (GC) have not yet been investigated.Methods:In vitro function of miR-646 in GC was evaluated using EdU assay, plate colony formation assay, and matrigel invasion assay. Real-time PCR or western blotting was performed to detect miR-646 and FOXK1 expressions. In vivo tumour growth and metastasis were conducted in nude mice.Results:MiR-646 expression was downregulated in GC tissues compared with adjacent normal tissues. Low miR-646 expression is associated with malignant progression. Transient transfection of GC cells with miR-646 inhibited their growth and migration. Moreover, miR-646 influenced the expression of epithelial–mesenchymal transition (EMT)-associated proteins. TGF-β1 treatment significantly suppressed the expression of miR-646 and overexpression of this microRNA counteracted the influence of the TGF-β1-induced EMT phenotype. In terms of the underlying mechanism, miR-646 directly targeted FOXK1. In vivo, it inhibited the FOXK1-mediated proliferation and EMT-induced metastasis. Consistently, inverse correlations were also observed between the expression of miR-646 and FOXK1 in human GC tissue samples. Furthermore, miR-646 regulated Akt/mTOR signalling after FOXK1.Conclusions:miR-646 inhibited GC cell proliferation and the EMT progression in GC cells by targeting FOXK1.

The biological role of miR-500a-5p has not yet been reported in the context of colorectal cancer (CRC). Here, we show that miR-500a-5p expression is decreased in CRC tissues compared with adjacent normal tissues. Low miR-500a-5p expression is associated with malignant progression. Moreover, transfection of CRC cells with miR-500a-5p induces G0/G1 cell cycle arrest and inhibits their growth and migration. Mechanistically, miR-500a-5p directly targets HDAC2 and inhibits HDAC2-mediated proliferation in CRC in nude mice. Furthermore, YY1 binds to the promoter of miR-500a-5p and negatively regulates its transcription. Restoration of miR-500a-5p expression is up-regulated via the p300/YY1/HDAC2 complex. Besides, therapeutic delivery of miR-500a-5p significantly suppresses tumour development in a xenograft tumour model and a HDAC2 inhibitor FK228-treated CRC model. Our studies demonstrate that miR-500a-5p functions as a tumour suppressor in CRC by targeting the p300/YY1/HDAC2 axis, which contributes to the development of and provides new potential candidates for CRC therapy.

Forkhead box (FOX) K1 is a member of the FOX transcription factor superfamily. High FOXK1 expression is associated with several cancers. However, whether FOXK1 expression contributes to gastric cancer (GC) development and progression remains unknown. We analyzed the FOXK1 promoter using the Promo software and found several binding sequence transcription factors, including c-jun. However, the molecular mechanism by which FOXK1 affects the c-jun-mediated malignant phenotype is poorly understood. Here, we found that FOXK1 protein expression was higher in 8/10 (80.0%) fresh cancer tissues compared with that in adjacent normal tissues. FOXK1 overexpression enhanced the proliferation, migration and invasion of GC cells. Moreover, FOXK1 expression was stimulated by transforming growth factor-β1 (TGF-β1). FOXK1 acted as a potential epithelial-to-mesenchymal transition (EMT) inducer by stimulating vimentin expression and inducing the loss of E-cadherin in stable FOXK1-transfected cells. The results of promoter reporter and chromatin immunoprecipitation assays demonstrated that c-jun directly binds to and activates the human FOXK1 gene promoter. A positive correlation was observed between the expression patterns of FOXK1 and c-jun in GC cells and tissue. FOXK1 and c-jun expression were correlated with tumor progression and represented significant predictors of overall survival in GC patients. However, the siRNA-mediated repression of c-jun in FOXK1-overexpressing cells reversed EMT, as well as the proliferative and metastatic phenotypes. In vivo, c-jun promoted FOXK1-mediated proliferation and metastasis via orthotopic implantation. The evidence presented here suggests that FOXK1-directed regulation by c-jun promote the development and progression of human GC.

Background and AimDelayed colonic postpolypectomy bleeding is the commonest serious complication after polypectomy. This study aimed to utilize massive sampling data of polypectomy to analyze risk factors for delayed postpolypectomy bleeding.Patients and MethodsThe endoscopic data of 5600 patients with 15553 polyps removed (2005 to 2013) were analyzed retrospectively through univariate analysis and multiple logistic regression analysis to evaluate the risk factors for delayed bleeding.ResultsDelayed postpolypectomy bleeding occurred in 99 polyps (0.6%). The rates of bleeding for different polypectomy methods including hot biopsy forcep, biopsy forcep, Argon Plasma Coagulation (APC), Endoscopy piecemeal mucosal resection (EPMR), Endoscopic Mucosal Resection (EMR), and snare polypectomy were 0.1%, 0.0%, 0.0%, 6.9%, 0.9% and 1.0%, respectively. The risk factors for delayed bleeding were the size of polyps over 10 mm (odds ratio [OR] = 4.6, 95% CI, 2.9–7.2), pathology of colonic polyps (inflammatory/hyperplastic, OR = 1; adenomatous, OR = 1.4, 95% CI, 0.7–2.6; serrated, OR = 1.5, 95% CI, 0.2–11.9; juvenile, OR = 4.3, 95% CI, 1.8–11.0; Peutz-Jegher, OR = 3.3, 95% CI, 1.0–10.7), and immediate postpolypectomy bleeding (OR = 2.9, 95% CI, 1.4–5.9). In addition, although polypectomy method was not a risk factor, compared with hot biopsy forcep, snare polypectomy, EMR, and EPMR had increased risks of delayed bleeding, with ORs of 3.2 (0.4–23.3), 2.8 (0.4–21.7) and 5.1 (0.5–47.7), respectively.ConclusionPolyp size over 10 mm, pathology of colonic polyps (especially juvenile, Peutz-Jegher), and immediate postpolypectomy bleeding were significant risk factors for delayed postpolypectomy bleeding.

Background: HOXD9, a Hox family member, is involved in cancer growth and metastasis. But, its regulation mechanism at the molecular level particularly in colorectal cancer (CRC), is mostly unknown. Methods: The HOXD9 protein expression levels were analyzed using immunofluorescence, immunohistochemistry (IHC) assays, and western blot. The in vivo and in vitro roles of HOXD9 in CRC were determined using colony formation and EdU incorporation, CCK-8, wound scratch and transwell invasion assay, and animal models. Results: Expression of HOXD9 was higher in CRC than in matched healthy tissues.High expression of HOXD9 has significantly associated with the American Joint Committee on Cancer (AJCC) stages, tumor differentiation, lymph node metastasis, and other serious invasions, and it had a poor prognosis. In vitro, HOXD9 encouraged proliferation, movement and EMT processes in cells of CRC. Also, TGF-β1 promoted the expression of HOXD9 and this effect was dependent on the dose and downregulation of HOXD9 repressed TGF-β1 -induced EMT. In vivo, HOXD9 promoted the invasive and metastasis of CRC cells via orthotopic implantation. Conclusions: The ectopic expression of HOXD9 promoted the invasion metastasis in cells of the colorectal tumor by induction of EMT in vitro and vivo. | 3933 LIU et aL How to cite this article: Liu M, Xiao Y, Tang W, et al. HOXD9 promote epithelial-mesenchymal transition and metastasis in colorectal carcinoma.

The transcription factor specificity protein 1 (Sp1) plays a role in the development and progression of various types of human cancers, while cancer stem cells (CSCs) are important in cancer cell self-renewal, resistance to chemotherapy and metastatic potential. This study investigated the role of Sp1 in colon CSC growth and apoptosis. Colon CSCs were successfully enriched using special culture medium and identified by typical CSC gene expression. In a quiescent state, these CSCs formed spheres with slow proliferation; overexpressed Sp1, CD44, CD166 and CD133 proteins; upregulated mesenchymal markers; and a downregulated epithelial marker were noted. In ex vivo experiments, the Sp1 protein was expressed in 74.8% of colon cancer tissues, whereas it was expressed only in 42.2% of the distant normal colon mucosae. Furthermore, inhibition of SP1 expression using Sp1 siRNA or mithramycin A (MIT) led to marked suppression of CSC growth and induced apoptosis. In addition, the percentage of CD44+/CD166+ cells was significantly downregulated both in vivo and in vitro following Sp1 inhibition. In conclusion, Sp1 suppression attenuated the characteristics of colon CSCs. Thus, Sp1 inhibition may be potentially useful for the future development of a novel therapeutic strategy to control colon cancer.

Among our patient group, the recurrence of advanced adenoma after polypectomy increased with the length of the surveillance interval. Based on our results, a 3-year follow-up of patients after polypectomy could be effective in preventing the recurrence of advanced adenoma in high-risk patients.