Fengkai Xu

DNMT1-microRNA126 epigenetic circuit contributes to esophageal squamous cell carcinoma growth via ADAM9-EGFR-AKT signaling

Purpose: MicroRNAs (miRNA) are involved in and are controlled by epigenetic regulation, and thereby form a reciprocal regulatory circuit. Using next-generation sequencing (NGS)–based miRNA profiling, this study aimed to discover esophageal squamous cell carcinoma (ESCC)–specific miRNAs and miRNA-related epigenetic modulations. Experimental Design: NGS-based miRNA profiles were generated for four pairs of ESCC tissues and adjacent normal tissues. In situ hybridization was used to assess miRNA expression and its correlation with prognosis. miRNA-related DNA methylations were identified using bisulfite genomic sequencing, and the role of DNA methyltransferase 1 (DNMT1) was investigated using RNA interference. miRNA targets were screened by mRNA sequencing, and functional validation was performed in vitro and in vivo. Results: NGS-based miRNA profiling identified 78 differentially expressed miRNAs in ESCC. Among them, microRNA126-3p (miR-126) was significantly downregulated, and its downregulation correlated with poor ESCC prognosis. Downregulation of miR-126 was due to promoter hypermethylation of its host gene, Egfl7. DNMT1 was aberrantly upregulated in ESCC and responsible for the hypermethylation of Egfl7. Intriguingly, DNMT1 was suppressed by overexpression of miR-126, indicating the existence of a regulatory feedback circuit. ADAM9 was identified as a key target of miR-126. Ectopic expression of miR-126 or silencing of ADAM9 reduced ESCC cell proliferation and migration by inhibiting epidermal growth factor receptor–AKT signaling. Conclusions: Our results indicate that miR-126 is a potential prognostic indicator for ESCC and suggest that a novel “DNMT1–miR-126 epigenetic circuit” is involved in ESCC progression. Consequently, miR-126–based epigenetic modulations may provide a basic rationale for new approaches to antitumor therapeutics. Clin Cancer Res; 21(4); 854–63. ©2014 AACR.

USP7 overexpression predicts a poor prognosis in lung squamous cell carcinoma and large cell carcinoma

In non-small cell lung cancer (NSCLC), both USP7 expression and p53 gene status were reported to be an indicator of poor prognosis in adenocarcinoma patients; however, its roles and mechanisms in lung squamous cell carcinoma and large cell carcinoma need to be clarified. The USP7 expression was examined in NSCLC tumors (excluding adenocarcinoma), their corresponding non-tumorous tissues, and NSCLC cells. Then, the prognostic role of USP7 was analyzed in 110 NSCLC samples (excluding the adenocarcinoma). Finally, the roles and mechanisms of USP7 in the proliferation, metastasis, and invasion of a NSCLC cell were assessed using a specific vshRNA. The USP7 expression was higher in NSCLC tissues compared to non-tumorous samples, accordingly, the high level of USP7 was detected in NSCLC cell lines compared with HBE cell. After the USP7 downregulation, the H460 cells exhibited decreased metastasis/invasion in vitro and in vivo. The preliminary mechanism study indicated overexpression of USP7 might regulate the p53-MDM2 pathway by inducing the MDM2 de-ubiquitination and subsequent stabilization, which resulted in the upregulation of the Bad phosphorylation. Additionally, we also found that USP7 might induce cell epithelial-mesenchymal transition to enhance the cell invasive ability. Clinically, USP7 overexpression significantly correlated with malignant phenotype. Furthermore, the 5-year overall survival in patients with USP7low was higher than that of USP7high. Multivariate analysis showed USP7 overexpression was an independent prognostic marker for these cancers. USP7 overexpression may regulate the survival and invasive properties of squamous cell carcinoma and large cell carcinoma cells, and may serve as a molecular target.

B cells expressing CD11b effectively inhibit CD4+ T-cell responses and ameliorate experimental autoimmune hepatitis in mice.

Increasing evidence in recent years has suggested that B cells act as a crucial regulator in autoimmune diseases. However, little is known about their role in autoimmune hepatitis (AIH) and the underlying regulatory mechanisms. In this study, we show that B cells ameliorated experimental AIH (EAH) by suppressing CD4+ T‐cell responses and that CD11b expression on B cells was required for the regulatory function of B cells. In vitro studies reveal that the suppressive function of CD11b was mediated by the impairment of T‐cell antigen receptor (TCR) signaling transduction and the promotion of TCR down‐regulation. Moreover, we show that the increased CD11b expression on B cells was interleukin (IL)−10 dependent and that additional IL‐10 stimulation promoted CD11b expression on B cells, thereby enhancing B‐cell regulatory effects. Conclusion: These findings reveal a previously unrecognized role for CD11b in B‐cell regulatory function and its protective effect on EAH. (Hepatology 2015;62:1563–1575)

Regulation of CXCR4/AKT-signaling-induced cell invasion and tumor metastasis by RhoA, Rac-1, and Cdc42 in human esophageal cancer

CXC chemokines and their cognate receptors have been implicated wildly in cancer pathogenesis. In the present study, we report a critical cause relationship between CXCR4 expression and tumorigenesis in the setting of human esophageal squamous cell carcinoma (ESCC). In ESCC cells, CXCR4 expression was significantly higher than in human esophageal epithelial cells (HEEC). Reduction of CXCR4 in ESCC cells reduced cell proliferation and invasion in vitro and tumor growth in vivo. Among the potential downstream targets of CXCR4-CXCL12 are RhoA, Rac-1, and Cdc42, which are likely to contribute to the invasiveness of ESCC cells. Finally, we found that CXCR4-CXCL12/AKT axis regulates RhoA, Rac-1, and Cdc42 to modulate cell invasion and tumor metastasis. Together, these results demonstrate a role for CXCR4 in ESCC metastasis and progression and suggest potential targets for therapeutic intervention.

Capn4 promotes non-small cell lung cancer progression via upregulation of matrix metalloproteinase 2

The expression of calpain small subunit 1 (Capn4) is correlated with the invasion of several types of tumors. However, the roles of Capn4 in non-small cell lung cancer (NSCLC) remain unclear. In this study, we found that the expression of Capn4 in NSCLC tissues was much higher than that in nontumorous samples. High levels of Capn4 expression were associated with lymph node metastasis and large tumor size in NSCLC patients. The 5-year overall survival rate in the Capn4high group was significantly lower than that in the Capn4low group. In multivariate analysis, Capn4 was identified as an independent prognostic factor for overall survival. Moreover, in an in vitro analysis, downregulation of Capn4 expression by siRNA suppressed the invasive potential of lung cancer cells. Finally, we demonstrated that Capn4 enhanced the invasion ability of lung cancer cells by upregulating the expression of matrix metalloproteinase 2. Our findings indicated that Capn4 may represent a potential therapeutic target and a novel prognostic marker of NSCLC.

Eukaryotic translation initiation factor 3B accelerates the progression of esophageal squamous cell carcinoma by activating β-catenin signaling pathway

Introduction Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive malignant tumors. Eukaryotic translation initiation factors 3B (EIF3B) is considered to influence tumor proliferation, invasion, apoptosis and cell cycle, which act together to promote the progression of tumors. However, the role of EIF3B in ESCC is unknown. This study aims to explore the clinical and biological role of EIF3B in ESCC. Results EIF3B expressions were up-regulated in both ESCC tissues and cell lines. Overexpression of EIF3B was associated with tumor depth, lymph node metastasis and advanced TNM stage. Importantly, patients with high EIF3B expression suffered shorter overall and disease-free survival. Knockdown of EIF3B could inhibit cell proliferation and invasion, promote cell apoptosis, and interfere the cell cycle in vitro. EIF3B-knockdown cells could form smaller subcutaneous tumors in vivo. Finally, we demonstrated EIF3B could activate β-catenin signaling pathway. Methods Immunohistochemical staining and Western blot were performed to detect the EIF3B expression in ESCC patient tissues and cell lines. The association between EIF3B expression and patients’ prognosis was analyzed by Kaplan-Meier and Cox regression. Then, CCK-8, colony-formation, Transwell and wound-healing assay were performed to compare the bio-functional change after knockdown of EIF3B. Flow cytometry was applied to analyze the change of cell apoptosis and cycle induced by EIF3B knockdown. Tumor xenograft assay was done to verify the in-vitro results. Conclusions EIF3B might serve as a novel marker for predicting prognosis of ESCC patients and as a potential therapeutic target, individually or together with other subunits of EIF3 complex.

Transcriptomic and functional network features of lung squamous cell carcinoma through integrative analysis of GEO and TCGA data

Lung squamous cell carcinoma (LUSC) is associated with poor clinical prognosis and lacks available targeted therapy. Novel molecules are urgently required for the diagnosis and prognosis of LUSC. Here, we conducted our data mining analysis for LUSC by integrating the differentially expressed genes acquired from Gene Expression Omnibus (GEO) database by comparing tumor tissues versus normal tissues (GSE8569, GSE21933, GSE33479, GSE33532, GSE40275, GSE62113, GSE74706) into The Cancer Genome Atlas (TCGA) database which includes 502 tumors and 49 adjacent non-tumor lung tissues. We identified intersections of 129 genes (91 up-regulated and 38 down-regulated) between GEO data and TCGA data. Based on these genes, we conducted our downstream analysis including functional enrichment analysis, protein-protein interaction, competing endogenous RNA (ceRNA) network and survival analysis. This study may provide more insight into the transcriptomic and functional features of LUSC through integrative analysis of GEO and TCGA data and suggests therapeutic targets and biomarkers for LUSC.

Pedicle muscle flap transposition for chronic empyema with persistent bronchopleural fistula: experience of a single clinical center in China

PurposeThe management of chronic empyema with persistent bronchopleural fistula (BPF) is a major challenge for surgeons. We report our experience of performing pedicle muscle flap transposition for chronic empyema with BPF in a clinical center in China.MethodsThe subjects of this study were 13 patients with postoperative chronic empyema and persistent BPF. The surgical procedure performed was chosen according to the degree of infection in the empyema cavity. Patients with mild contamination underwent one-stage cavity decortication with flap transposition, whereas patients with severe infection underwent two-stage surgery including open-window thoracostomy and pedicle muscle flap transposition.ResultsFive patients underwent one-stage surgery, followed by an uneventful postoperative course in all except one. The other eight patients underwent two-stage surgery. The fistulas closed spontaneously during the course of dressings and six of these eight patients underwent second-stage surgery uneventfully. A bronchopleurocutaneous sinus developed in the wounds of the other two patients.ConclusionsPedicle muscle flap transposition is a viable option for chronic empyema with BPF; however, surgical procedures should be selected according to the degree of contamination. For two-stage surgery, obliteration of the cavity should be considered, preferably after closure of the fistula.