MicroRNA-214-3p targets the PLAGL2-MYH9 axis to suppress tumor proliferation and metastasis in human colorectal cancer.

Evidence has shown that microRNAs (miRNAs) participate in the progression of CRC. Previous studies have indicated that miR-214-3p is abnormally expressed in various malignant tumors. However, the biological function it plays in CRC and the potential mechanism are unclear. Here, we demonstrated that miR-214-3p was obviously downregulated in CRC. Moreover, we found a strong correlation between the miR-214-3p level and tumor size and lymphatic metastasis. Furthermore, when miR-214-3p was decreased by an Lv-miR-214-3p inhibitor, the proliferation and migration of SW480 and HCT116 cells were significantly increased. As expected, the ability of proliferation and migration was significantly suppressed when miR-214-3p was overexpressed in DLD1 cells. According to the dual-luciferase reporter results, PLAGL2 was found to be a direct downstream molecule of miR-214-3p. Chromatin immunoprecipitation (CHIP) confirmed that MYH9, a well-known cytoskeleton molecule in CRC, was a direct targeting gene of PLAGL2. Silencing PLAGL2 or MYH9 could reverse the effect of a miR-214-3p inhibitor on CRC cells. In summary, our studies proved that low expression of miR-214-3p and overexpression of downstream PLAGL2 in CRC indicated a poor prognosis. MiR-214-3p suppressed the malignant behaviors of colorectal cancer by regulating the PLAGL2/MYH9 axis. MiR-214-3p might be a novel therapeutic target or prognostic marker for CRC.

PLAGL2 promotes epithelial-mesenchymal transition and mediates colorectal cancer metastasis via ß-catenin-dependent regulation of ZEB1.

BACKGROUND: We previously demonstrated that the pleomorphic adenoma gene like-2 (PLAGL2) is involved in the pathogenesis of Hirschsprung disease. Enhanced PLAGL2 expression was observed in several malignant tumours. However, the exact function of PLAGL2 and its underlying mechanism in colorectal cancer (CRC) remain largely unknown. METHODS: Immunohistochemical analysis of PLAGL2 was performed. A series of in vitro and in vivo experiments were conducted to reveal the role of PLAGL2 in the progression of CRC. RESULTS: Enhanced PLAGL2 expression was significantly associated with EMT-related proteins in CRC. The data revealed that PLAGL2 promotes CRC cell proliferation, migration, invasion and EMT both in vitro and in vivo. Mechanistically, PLAGL2 promoted the expression of ZEB1. PLAGL2 enhanced the expression and nuclear translocation of ß-catenin by decreasing its phosphorylation. The depletion of ß-catenin neutralised the regulation of ZEB1 that was caused by enhanced PLAGL2 expression. The small-molecule inhibitor PNU-74654, also impaired the enhancement of ZEB1 that resulted from the modified PLAGL2 expression. The depletion of ZEB1 could block the biological function of PLAGL2 in CRC cells. CONCLUSIONS: Collectively, our findings suggest that PLAGL2 mediates EMT to promote colorectal cancer metastasis via ß-catenin-dependent regulation of ZEB1.

Increased miR-214 expression suppresses cell migration and proliferation in Hirschsprung disease by interacting with PLAGL2.

BACKGROUND: The miR-214 has been reported to be associated with various diseases, but its involvement in the pathophysiology of Hirschsprung disease (HSCR) is almost completely unexplored. METHODS: In our study, we conducted a series of experiments to unravel the biological role of miR-214 in the pathophysiology of HSCR. qRT-PCR and western blotting were utilized to investigate the relative expression levels of miR-214, mRNAs, and proteins of related genes in colon tissues from 20 controls without HSCR and 24 patients with HSCR. The potential biological role of miR-214 in two cell lines (SKN-SH and SH-SY5Y) was assessed using the CCK8 assay, EdU staining, transwell assay, and flow cytometry. The dual-luciferase reporter assay was used to confirm PLAGL2 as a common target gene of miR-214. RESULTS: All results suggested that miR-214 is upregulated in HSCR tissue samples compared with controls. Additionally, we found that miR-214 could inhibit cell proliferation and migration by directly downregulating the expression of PLAGL2, and the extent of the miR-214-mediated inhibitory effects could be rescued by a PLAGL2 overexpression plasmid. CONCLUSION: Our results revealed that miR-214 is indeed involved in the pathophysiology of HSCR and suppresses cell proliferation and migration by directly downregulating PLAGL2 in cell models.

Downregulation of DAPK1 promotes the stemness of cancer stem cells and EMT process by activating ZEB1 in colorectal cancer.

Cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) play an important role in the metastasis and chemoresistance in the context of colorectal cancer (CRC). Downregulation of death associated protein kinase 1 (DAPK1) may promote metastasis and chemoresistance of cancer cells through various mechanisms. However, the association between DAPK1 and CSCs or EMT has not been explored. In this study, we demonstrated that DAPK1 was associated with elevated stemness of CSCs in patients with CRC. Silencing of DAPK1 in CRC cell lines promoted the metastasis and chemoresistance due to increased stemness of CSCs and enhanced mesenchymal phenotype, an effect that was mediated via activation of the transcription factor, zinc finger E-box binding homeobox 1 (ZEB1). Blockade of this signaling pathway attenuated the stemness of CSCs and rescued the EMT process. DAPK1-ZEB1 may lie at the interface of TGF-ß and WNT pathways and participate in both CSCs and EMT process. Targeted therapies aimed at DAPK1-ZEB1 pathway may inhibit the chemoresistance and metastasis of CRC. KEY MESSAGES: Downregulation of DAPK1 promotes chemoresistance and metastasis of CRC. Inhibition of DAPK1 promotes the stemness of cancer stem cells and EMT process. DAPK1-ZEB1 may lie at the interface of TGF-ß and WNT pathways. DAPK1-ZEB1 participates in both CSCs and EMT process.

Nuclear factor I/B promotes colorectal cancer cell proliferation, epithelial-mesenchymal transition and 5-fluorouracil resistance.

Nuclear factor I/B (NFIB) is a widely studied transcription factor that participates in tumor progression; nevertheless, studies on NFIB in colorectal cancer (CRC) are limited. In our study, Western blot and RT-PCR analyses showed that NFIB was overexpressed in CRC tissues and cell lines, which was consistent with our bioinformatic analysis results. Furthermore, NFIB expression was closely related to the TNM stage of CRC. NFIB promoted cell proliferation and migration and inhibited cell apoptosis in vitro. Meanwhile, we discovered that NFIB accelerated xenograft tumor growth in vivo. In addition, NFIB weakened the sensitivity of CRC cells to 5-fluorouracil (5-FU). NFIB induced epithelial-mesenchymal transition (EMT) by upregulating snail expression, which was accompanied by decreased E-cadherin and Zo-1 expression and increasedd Vimentin expression. Because the Akt pathway plays an important role in CRC progression, we examined whether there was a correlation between NFIB and the Akt pathway in cell proliferation and migration. Our results showed that NFIB promoted cell proliferation and increased 5-FU resistance by activating the Akt pathway. In summary, our findings suggested that NFIB induced EMT of CRC cells via upregulating snail expression and promoted cell proliferation and 5-FU resistance by activating the Akt pathway.

Platelet-derived growth factor-D promotes colorectal cancer cell migration, invasion and proliferation by regulating Notch1 and matrix metalloproteinase-9.

Colorectal cancer (CRC) has been one of the most common types of cancer for decades worldwide. The pathogenesis of CRC is associated with the processes of activating oncogenes and inactivating anti-oncogenes. Platelet-derived growth factor-D (PDGF-D) was confirmed to regulate migration, invasion, proliferation, apoptosis and metastasis in various cancer cells. Overexpression of PDGF-D exists in a number of human malignancies, including pancreatic, prostate and breast cancer. However, the expression and function of PDGF-D and its associated molecular mechanism in CRC remain unclear. Thus, the expression of PDGF-D was detected in CRC tissues and human colon cancer lines. Subsequently, the effects of PDGF-D on the invasion, migration and proliferation of cancer cells were investigated. The corresponding molecular mechanism had also been explored. The present study revealed that PDGF-D was upregulated not only in CRC tissues but also in CRC cell lines, and simultaneously, facilitated the processes of migration, invasion and proliferation. Silencing PDGF-D in the SW480 cell line inhibited migration, invasion and proliferation distinctly, with reduced expression of Notch1 and matrix metalloproteinase-9. Furthermore, upregulating PDGF-D in HCT116 cells led to the opposite results. These findings indicate that PDGF-D may be developed into a potential therapeutic target for CRC treatment.

Correlation of DAPK1 methylation and the risk of gastrointestinal cancer: A systematic review and meta-analysis.

OBJECTIVE: One of the critical mechanisms of gastrointestinal cancer pathogenesis is the silencing of death associated protein kinase 1 (DAPK1), which could be caused by aberrant methylation of the promoter. However, the relationship between DAPK1 methylation and the risk of gastrointestinal cancer is still controversial. Hence, we conducted this study to determine the potential correlation. METHODS: Eligible publications were searched in the Pubmed, Embase, and Cochrane Library through November 2016 according to the inclusion criteria and exclusion criteria. Revman 5.3 and Stata 12.0 software were used to analyze the relevant data regarding the association between the frequency of DAPK1 methylation and gastrointestinal cancer. RESULTS: A total of 22 studies with 2406 patients were included in this meta analysis. Methylation of DAPK1 was positively related with the risk of gastrointestinal cancer (odds ratio [OR] = 5.35, 95% confidence interval [CI]: 2.76-10.38, P<0.00001, random effects model). The source of heterogeneity was analyzed by sensitivity analysis and subgroup analysis. After omitting one heterogeneous study, the I2 decreased and the OR increased in pooled analysis. Also, the heterogeneity decreased most significantly in the subgroup of studies that had a sample size of less than 60 cases. Then, the correlations between DAPK1 methylation and clinicopathological features of gastrointestinal cancer were assessed. DAPK1 methylation was positively correlated with the lymph node (N) stage (positive vs. negative, OR = 1.45, 95%CI: 1.01-2.06, P = 0.04, fixed effects model) and poor differentiation (OR = 1.55, 95%CI: 1.02-2.35, P = 0.04, fixed effects model) in gastric cancer, and the association was significant among Asian patients. However, among cases of gastrointestinal cancer, the association between DAPK1 methylation and tumor (T) stage, N stage, distant metastasis (M) stage, and cancer differentiation were not statistically significant. CONCLUSIONS: DAPK1 methylation is a potential biomarker for the early diagnosis of gastrointestinal cancer. Further analysis of the clinicopathological features indicated that aberrant methylation of DAPK1 is positively associated with the tumorigenesis of gastrointestinal cancer, and metastasis of gastric cancer.

Correlation of metastasis characteristics with prognosis in gastric mixed adenoneuroendocrine carcinoma: Two case reports.

RATIONALE: This article is aimed to retrospect the clinicopathological data of 2 cases of gastric MANENCs. MANEC is a rare biphasic tumor type that is coexistence of dual neuroendocrine and adenocarcinoma differentiation with each composing exceeding 30% volume. Gastric MANEC have just been reported anecdotally in the literature due to their rarity and heterogeneity. According to our study, these neoplasms have 3 different metastasis patterns: only adenocarcinomatous or neuroendocrine carcinoma and both of the 2 components. We first focus on the correlation of metastasis characteristics with prognosis in gastric MANEC, which may be potential implications for the choice of chemotherapy. PATIENT CONCERNS: The 2 cases of patient shared several symptoms: epigastric discomfort, weight loss, hematemesis, or melena. DIAGNOSIS: The 2 patients were diagnosis as MANEC based on the identification of histopathological analysis. In case 1, the poor differentiated adenocarcinoma accounted for 30%, the neuroendocrine part account for 70% and both of the 2 components metastasized to the lymph nodes, whereas in case 2, poorly differentiated adenocarcinoma accounted for 70%, the neuroendocrine part for 30% and only the glandular component invaded regional lymph nodes. INTERVENTIONS: The first patient underwent laparoscopic radical gastrectomy and underwent adjuvant chemotherapy, combination of cisplatin, and etoposide successfully. The second patient received radical gastronomy, and did not receive any chemotherapy due to general weakness. OUTCOMES: The first patient is alive with no evidence of recurrence, and the second patient died 6 months after the operation. LESSONS: The assessment of metastatic sites should be a routine pathological practice, which is crucial for clinical decision-making and the selection of management.

PDGF-D promotes cell growth, aggressiveness, angiogenesis and EMT transformation of colorectal cancer by activation of Notch1/Twist1 pathway.

Platelet-derived growth factor-D (PDGF-D) plays a crucial role in the progression of several cancers. However, its role in colorectal cancer (CRC) remains unclear. Our study showed that PDGF-D was highly expressed in CRC tissues and was positively associated with the clinicopathological features. Down-regulation of PDGF-D inhibited the tumor growth, migration and angiogenesis of SW480 cells in vitro and in vivo. Whereas up-regulation of PDGF-D promoted the malignant behaviors of HCT116 cells. Moreover, PDGF-D up-regulated the expression of Notch1 and Twist1 in CRC cells. In addition, PDGF-D expression promoted Epithelial to mesenchymal transition (EMT), which was accompanied with decreased E-cadherin and increased Vimentin expression. Consistently, PDGF-D, Notch1, and Twist1 are obviously up-regulated in transforming growth factor-beta 1 (TGF-ß1) treated HCT116 cells. Since Notch1 and Twist1 play an important role in EMT and tumor progression, we examined whether there is a correlation between Notch1 and Twist1 in EMT status. Our results showed that up-regulation of Notch1 was able to rescue the effects of PDGF-D down-regulation on Twist1 expression in SW480 cells, whereas down-regulation of Notch1 reduced Twist1 expression in HCT116 cells. Furthermore, we found that Twist1 promoted EMT and aggressiveness of CRC cells. These results suggest that PDGF-D promotes tumor growth and aggressiveness of CRC, moreover, down-regulation of PDGF-D inactivates Notch1/Twist1 axis, which could reverse EMT and prevent CRC progression.

Prognostic and clinical value of Sirt1 expression in gastric cancer: A systematic meta-analysis.

Many studies have reported that the expression of silent information regulator 1 (Sirt1) is associated with the clinical features and prognosis of patients with gastric cancer, but the exact function remains controversial. We conducted this study to illustrate the clinical and prognostic value of Sirt1 in gastric cancer. The related publications before December 2015 were searched in the databases including Pubmed, Cochrane Library, Embase and China National Knowledge Infrastructure (CNKI). The studies were included and excluded according to the inclusion criteria and exclusion criteria. The 3- and 5-year overall survival (OS) and clinical features such as age, T stage, N stage and differentiation were analyzed by software RevMan 5.3. A total of 1650 patients in 7 studies were included according to the inclusion criteria and exclusion criteria. The high expression of Sirt1 was found in 58.4% cases by immunohistochemistry. High expression of Sirt1 was closely linked with the 3-year OS (OR=0.25, 95% CI: 0.16-0.39, P<0.00001, fixed), patient's age (≥60 years old vs. <60 years old; OR=1.43, 95% CI: 1.06-1.93, P=0.02, fixed), T stage (T3+T4 vs. T1+T2; OR=1.45, 95% CI: 1.08-1.94, P=0.01, fixed), N stage (N1+N2+N3 vs. N0; OR=3.47, 95% CI: 2.39-5.05, P<0.00001, fixed) and tumor differentiation (G1+G2 vs. G3; OR=0.50, 95% CI: 0.35-0.69, P<0.0001, fixed). Nevertheless, it seemed that high expression of Sirt1 was not associated with 5-year OS (OR=0.44, 95% CI: 0.15-1.28, P=0.13, random). It was suggested that the high expression of Sirt1 implies a poor prognosis of gastric cancer patients in a relatively short period (3 years), but not in a long time (≥5 years). The expression of Sirt1 is also linked with patients' age, T stage, N stage and tumor differentiation.

Treatment of aganglionic megacolon mice via neural stem cell transplantation.

To explore a potential methodology for treating aganglionic megacolon, neural stem cells (NSCs) expressing engineered endothelin receptor type B (EDNRB) and glial cell-derived neurotrophic factor (GDNF) genes were transplanted into the aganglionic megacolon mice. After transplantation, the regeneration of neurons in the colon tissue was observed, and expression levels of differentiation-related genes were determined. Primary culture of NSCs was obtained from the cortex of postnatal mouse brain and infected with recombinant adenovirus expressing EDNRB and GDNF genes. The mouse model of aganglionic megacolon was developed by treating the colon tissue with 0.5 % benzalkonium chloride (BAC) to selectively remove the myenteric nerve plexus that resembles the pathological changes in the human congenital megacolon. The NSCs stably expressing the EDNRB and GDNF genes were transplanted into the benzalkonium chloride-induced mouse aganglionic colon. Survival and differentiation of the implanted stem cells were assessed after transplantation. Results showed that the EDNRB and GDNF genes were able to be expressed in primary culture of NSCs by adenovirus infection. One week after implantation, grafted NSCs survived and differentiated into neurons. Compared to the controls, elevated expression of EDNRB and GDNF was determined in BAC-induced aganglionic megacolon mice with partially improved intestinal function. Those founding indicated that the genes transfected into NSCs were expressed in vivo after transplantation. Also, this study provided favorable support for the therapeutic potential of multiple gene-modified NSC transplantation to treat Hirschsprung's disease, a congenital disorder of the colon in which ganglion cells are absent.