An E2F1/DDX11/EZH2 Positive Feedback Loop Promotes Cell Proliferation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for one of the leading causes of cancer-related death, and is attributed to the dysregulation of genes involved in genome stability. DDX11, a DNA helicase, has been implicated in rare genetic disease and human cancers. Yet, its clinical value, biological function, and the underlying mechanism in HCC progression are not fully understood. Here, we show that DDX11 is upregulated in HCC and exhibits oncogenic activity via EZH2/p21 signaling. High expression of DDX11 is significantly correlated with poor outcomes of HCC patients in two independent cohorts. DDX11 overexpression increases HCC cell viabilities and colony formation, whereas DDX11 knockdown arrests cells at G1 phase without alteration of p53 expression. Ectopic expression of DDX11 reduces, while depletion of DDX11 induces the expression of p21. Treatment of p21 siRNA markedly attenuates the cell growth suppression caused by DDX11 silence. Further studies reveal that DDX11 interacts with EZH2 in HCC cells to protect it from ubiquitination-mediated protein degradation, consequently resulting in the downregulation of p21. In addition, E2F1 is identified as one of the upstream regulators of DDX11, and forms a positive feedback loop with EZH2 to upregulate DDX11 and facilitate cell proliferation. Collectively, our data suggest DDX11 as a promising prognostic factor and an oncogene in HCC via a E2F1/DDX11/EZH2 positive feedback loop.

PRMT6 promotes endometrial cancer via AKT/mTOR signaling and indicates poor prognosis

Arginine methylation plays essential roles in post-transcriptional modification and signal transduction. Dysregulation of protein arginine methyltransferases (PRMTs) has been reported in human cancers, yet the expression and biological function of PRMT6 in endometrial cancer (EMC) remains unclear. Here, we show that PRMT6 is upregulated in EMC and exhibits oncogenic activities via activation of AKT/mTOR pathway. The expression of PRMT6 in EMC is much higher than that in the adjacent nontumorous tissues. Elevated PRMT6 expression is significantly associated with higher histological tumor grade and unfavorable prognosis in two independent cohorts consisting of a total of 564 patients with EMC. In vitro data demonstrate that PRMT6 expression was identified as a downstream target of miR-372-3p. Ectopic expression of miR-372-3p downregulates PRMT6. Overexpression of PRMT6 promotes EMC cell proliferation and migration, whereas knockdown of PRMT6 leads to opposite phenotypes. Mechanistically, PRMT6 induces the phosphorylation of AKT and mTOR in EMC cells. Inhibition of AKT/mTOR signaling by MK2206 or rapamycin attenuates the PRMT6-mediated EMC progression. In clinical samples, high expression of PRMT6 was correlated to low expression of miR-372-3p and high expression of phosphorylated AKT. Collectively, our findings suggest PRMT6 may function as an oncogene to promote tumor progression, and be of prognostic value to predict disease-free survival of patients with EMC. The newly identified miR-372-3p/PRMT6/AKT/mTOR axis represents a new promising target for EMC management.

ESCO2 inhibits tumor metastasis via transcriptionally repressing MMP2 in colorectal cancer

Background

Establishment of cohesion 1 homolog 2 (ESCO2) plays important roles in the regulation of cohesion and genomic stability and has been implicated in human cancers. Yet, its clinical significance and biological function in colorectal cancer (CRC) are unknown.

Methods

The expression of ESCO2 was examined by quantitative real-time PCR, Western blot, and immunohistochemistry. The role of ESCO2 in the tumor metastasis of CRC and the related mechanisms were investigated using in vitro and in vivo models.

Results

In this study, we show that low expression of ESCO2 in CRC was closely correlated with lymphatic and distant metastasis. Patients with low ESCO2 expression experienced shorter overall survival and disease-free survival in two independent cohorts containing a total of 587 CRC cases. ESCO2 overexpression suppressed, whereas ESCO2 knockdown promoted cell migration in vitro and tumor metastasis in vivo via modulation of epithelial–mesenchymal transition (EMT) process. Mechanistically, ESCO2 inhibited the transcriptional activity of MMP2 promoter to downregulate its expression. Reexpression of MMP2 partially attenuated the ESCO2-mediated malignant phenotypes.

Conclusion

Collectively, our data suggest that ESCO2 serves as a potential prognostic factor and exerts antimetastatic activity in CRC.

CBX1 Indicates Poor Outcomes and Exerts Oncogenic Activity in Hepatocellular Carcinoma

Dysregulation of chromobox proteins contributes to the progression of human diseases. CBX1 has been implicated in epigenetic control of chromatin structure and gene expression, but its role in human cancers remains largely unknown. Here we show that CBX1 exhibits oncogenic activities in hepatocellular carcinoma (HCC) and indicates poor outcomes. The expression of CBX1 was noticeably increased, at both mRNA and protein levels, in HCC tissues and cell lines, compared with the nontumorous ones. High CBX1 expression was significantly associated with larger tumor size, poor tumor differentiation and tumor vascular invasion. Patients with elevated expression of CBX1 were frequently accompanied with unfavorable overall and disease-free survivals in two independent cohorts consisting of 648 HCC cases. The prognostic value of CBX1 was further confirmed by stratified survival analyses. Multivariate cox regression model suggested CBX1 as an independent factor for overall survival (hazard ratio = 1.735, 95% confident interval: 1.342–2.244, P < .001). In vitro data demonstrated that CBX1 overexpression promoted cell proliferation and migration, whereas the knockdown of CBX1 resulted in the opposite phenotypes. Mechanistically, CBX1 interacted with transcription factor HMGA2 to activate the Wnt/β-Catenin signaling pathway. Suppression of β-Catenin by siRNA or specific inhibitor XAV-939 markedly attenuated CBX1-mediated cell growth. Collectively, our findings indicate that CBX1 functions as an oncogene and may serve as a potential prognostic biomarker in HCC.

UBE2S enhances the ubiquitination of p53 and exerts oncogenic activities in hepatocellular carcinoma

Ubiquitin-conjugating enzyme E2S (UBE2S) plays pivotal roles in the progression of human cancers. However, its clinical significance and role in hepatocellular carcinoma (HCC) remain unknown. Here, we show that UBE2S is upregulated in HCC and exhibits oncogenic activities via enhancing the ubiquitination of p53. Increased expression of UBE2S was significantly correlated with higher serum AFP level, higher pathological grade, advanced TNM stage, larger tumor size, vascular invasion and unfavorable patient survivals in two independent cohorts containing a total of 845 patients with HCC. Multivariate analyses by cox regression model suggested UBE2S as an independent factor for overall survival. In vitro experiments demonstrated that UBE2S overexpression promoted, whereas UBE2S knockdown suppressed cell proliferation and migration via modulation of p53 signaling pathway. Ectopic expression of UBE2S upregulated the expression of p53 and its downstream effectors, such as p21 and Cyclin D1. Mechanistically, UBE2S enhanced the ubiquitination of p53 protein to facilitate its degradation in HCC cells. Re-expression of p53 partially attenuated the UBE2S-promoted malignant phenotypes. Collectively, our study provides compelling evidence that UBE2S is a potential prognostic factor and functions as an oncogene in HCC.

HEY2, a target of miR-137, indicates poor outcomes and promotes cell proliferation and migration in hepatocellular carcinoma

HEY2, a bHLH transcription factor, has been implicated in the progression of human cancers. Here, we showed that HEY2 expression was markedly increased in HCC, compared with the adjacent nontumorous tissues. High HEY2 expression was closely correlated with tumor multiplicity, tumor differentiation and TNM stage. Kaplan-Meier analyses revealed that HEY2 expression was significantly associated with poor overall and disease-free survival in a training cohort of 361 patients with HCC. The prognostic implication of HEY2 was validated in another cohort of 169 HCC patients. Multivariate Cox regression model indicated HEY2 as an independent factor for overall survival in HCC (Hazard ratio = 1.645, 95% confident interval: 1.309-2.067, P<0.001). We also demonstrated that HEY2 expression was inhibited by miR-137. In clinical samples, HEY2 expression was reversely associated to miR-137 expression. Furthermore, overexpression of HEY2 increased cell viabilities, colony formation and cell migration, whereas knockdown of HEY2 resulted in the opposite phenotypes. Collectively, our data suggest HEY2 as a promising biomarker for unfavorable outcomes and a novel therapeutic target for the clinical management of HCC.

Prognostic factors of regression and relapse of complex atypical hyperplasia and well-differentiated endometrioid carcinoma with conservative treatment

OBJECTIVE

To evaluate possible prognostic factors regarding regression and relapse of complex atypical hyperplasia (CAH) and well-differentiated endometrioid adenocarcinoma (WDC) treated with conservative treatment.

METHODS

The retrospective study reviewed clinicopathologic, treatment, regression and relapse data from patients diagnosed with CAH or WDC who were treated with conservative treatment at 4 institutions. Potential factor evaluation was performed. SPSS 16 was used for statistical analyses.

RESULTS

Eighty-eight patients were included (51 had WDC, and 37 had CAH). Regression was evaluated in 88 patients, with a median follow-up of 61 (range 15-95) months. Seventy-seven (87.5%) patients regressed, and 11 (12.5%) had persistent or progressive disease. Univariate and multivariate analyses showed no factors associated with regression. Relapse was evaluated in 71 patients, with median follow-up of 54 (range 8-86) months. Twenty-five/71 (35.2%) patients experienced relapse. On univariate analysis, body mass index (BMI) 30 or higher (p=0.001), WCD at initial biopsy (p=0.017) and positive expression of post-treatment ki67 (p=0.033) were associated to a higher relapse probability. However, only BMI 30 or higher was significant on multivariate analysis (p=0.012). The Kaplan-Meier analysis revealed a higher relapse probability in the patients with BMI 30 or higher (p=0.001).

CONCLUSION

Obesity seems to be a risk factor for relapse of CAH or WDC with conservative treatment.

Effect of the solvent-non-solvent pairs on the surface morphology and release behaviour of ethylcellulose microcapsules prepared by non-solvent-addition phase separation method

Four solvent-non-solvent pairs (ethyl-acetate-cyclohexane, dichloromethane-cyclohexane, acetone-cyclohexane and dichloromethane-n-hexane) with different solubility parameter differences were chosen to prepare ethylcellulose microcapsules containing theophylline by using non-solvent-addition phase separation method. The results showed that the surface morphology and release behaviour of microcapsules were greatly affected by different solvent-non-solvent pairs. The surface of the microcapsules prepared from the system of high solubility parameter difference was more smooth than those from the systems of low solubility parameter difference. The release rate of the drug from microcapsules decreased with increasing solubility parameter difference of the preparative system. The determination of the wall thickness and porosity of the microcapsules could reasonably explain the release characteristics. The porosity of the microcapsules decreased with the increase of solubility parameter difference of the preparative system, but the wall thickness of the microcapsules showed a corresponding increase. The release of the drug from various ethylcellulose microcapsules fitted first-order kinetics with biphasic release profiles.