Liuxing Wang

Elevated serine protease HtrA1 inhibits cell proliferation, reduces invasion, and induces apoptosis in esophageal squamous cell carcinoma by blocking the nuclear factor-κB signaling pathway.

Emerging evidence has demonstrated that high-temperature requirement protein A1 (HtrA1) appears to be involved in several important biological processes in mammals such as growth, apoptosis, embryogenesis, invasion, metastasis, and cancer and has been verified to be reduced in a variety of human tumors. However, its precise functions and molecular mechanisms in esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we detected HtrA1 level in ESCC tissues and cells and investigated the biological roles of HtrA1 in ESCC. We found that expressions of HtrA1 mRNA and protein in ESCC tissues and cells were significantly lower than those in normal esophageal epithelial tissues and cells (P < 0.05). Expressions of HtrA1 mRNA and protein were closely associated with TNM staging and lymph node metastasis (P < 0.05). Additionally, the survival rate of patients with low HtrA1 level was lower than those patients with high HtrA1 level (P < 0.05). Elevated HtrA1 level markedly inhibited cell proliferation in vitro and in vivo, reduced cell invasion in vitro, and induced cell apoptosis. Notably, HtrA1 overexpression inhibited phosphorylation levels of IκBα and p65 subunit of the NF-κB signaling pathway, but increased total IκBα level, coupled with decreases of Ki-67, Bcl-2, Bcl-xL, cyclin D1, and MMP-9 proteins and increase of caspase-3 activity. Overall, these data suggest that HtrA1 may play critical roles in the tumorgenesis and progression of ESCC, and HtrA1 overexpression exerts its anti-tumor effect by blocking the NF-κB signaling pathway; thus, manipulation of HtrA1 may be an effective molecular target for ESCC treatment.

Correlation between the expression of DNMT1, and GSTP1 and APC, and the methylation status of GSTP1 and APC in association with their clinical significance in prostate cancer

The aim of the present study was to investigate the correlation between the expression of DNA (cytosine-5)-methyltransferase 1 (DNMT1), glutathione S-transferase-P1 (GSTP1) and adenomatous polyposis coli (APC), and the methylation status of GSTP1 and APC in prostate cancer (PCa) and benign prostatic hyperplasia (BPH), and to examine its clinical significance. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of DNMT1, GSTP1 and APC in 56 samples of PCa tissue and 10 samples of BPH tissue. Methylation-specific-PCR was used to detect the methylation status of the CpG island promoters of GSTP1 and APC. The positive rate of expression of DNMT1 in poorly-differentiated PCa, moderately-differentiated PCa, well-differentiated PCa and BPH was 86.7%, 70.6%, 55.6% and 30.0%, respectively (P<0.05); for GSTP1, the positive rate was 13.3%, 29.4%, 44.4% and 90.0%, respectively (P<0.05); and for APC, the positive rate was 23.3%, 47.6%, 55.6% and 70.0%, respectively (P<0.05). The correlation coefficient for the association between the expression of DNMT1 and GSTP1 was −0.891 (P<0.05). Between the expression of DNMT1 and APC, the correlation coefficient was −0.721 (P<0.05). GSTP1 and APC were hypermethylated in the majority of PCa tissue samples. The positive rate of methylation of these genes in poorly-differentiated PCa was 83.3% and 73.3%, respectively. By contrast, hypomethylation (or demethylation) was observed in BPH samples, in which the positive rate of methylation was 10.0% and 20.0%, respectively (P<0.05). The increased expression of DNMT1, and the reduced expression of GSTP1 and APC have an important role in the development of PCa. Due to the high expression of DNMT1 mRNA, it is likely that the hypermethylation of CpG islands contributed to the silencing of GSTP1 and APC in PCa tissues.

NF-κBP65 promotes invasion and metastasis of oesophageal squamous cell cancer by regulating matrix metalloproteinase-9 and epithelial-to-mesenchymal transition

NF‐κB has been recognized as one of the factors responsible for the development of cancer; however, the mechanism by which high expression of NF‐κB contributes to the progression of human oesophageal squamous cell cancer (ESCC) is not fully understood. In our investigations, NF‐κBP65 was overexpressed in human ESCC tissues, especially in ESCC tissues with deep invasion and lymph node metastasis. Suppression of NF‐κBP65 by siRNA decreased the invasion and proliferation ability of EC9706 cells in vitro. Furthermore, siRNA‐mediated NF‐κBP65 knock‐down could lead to the downregulation of MMP‐9, a metastasis‐related gene. Reduced E‐cadherin is a hallmark of invasive carcinomas that have acquired epithelial–mesenchymal transition (EMT) phenotypes and Vimentin is another molecule that is used widely as a marker of the EMT. We found upregulation of E‐cadherin expression and downregulation of Vimentin was induced by NF‐κBP65 siRNA, which suggests that NF‐κBP65 siRNA could inhibit the invasion and proliferation ability of ECSS through attenuating the expression of MMP‐9 and EMT. Thus, ESCC NF‐κBP65 could be a useful target for cancer prevention and therapy.

Epigallocatechin‑3‑gallate inhibits the proliferation and migration of human ovarian carcinoma cells by modulating p38 kinase and matrix metalloproteinase‑2

Epigallocatechin‑3‑gallate (EGCG), a major catechin in green tea, has recently been reported to exhibit anticancer effects on a number of types of cancer cells in vitro; however, the molecular mechanisms of this anticancer effect remain poorly understood. In the current study, the effects of EGCG on the proliferation and migration of the OVCAR‑3 human ovarian carcinoma cell line were investigated. Cells were treated with EGCG and their proliferation rates were determined by an MTT assay. In addition, cell migration was detected by transwell assay. The activity of mitogen‑activated protein kinases (MAPKs) and the expression of matrix metalloproteinase‑2/9 (MMP‑2/9) were examined by western blotting. The results showed that EGCG significantly inhibited (P<0.05) the proliferation of OVCAR‑3 cells in a time‑ and concentration‑dependent manner. EGCG (100 µM) time‑dependently increased (P<0.05) the activity of p38, but not extracellular signal‑regulated kinases 1/2. SB203580, a specific p38 MAPK inhibitor, completely diminished EGCG‑induced phosphorylation of p38 and partially blocked EGCG‑inhibited OVCAR‑3 cell proliferation. Furthermore, EGCG (0‑100 µM) dose‑dependently inhibited (P<0.05) OVCAR‑3 cell migration. The protein expression levels of MPP‑2, but not MMP‑9, were dose‑dependently decreased following treatment with EGCG (0‑100 µM) for 48 h. These data indicated that EGCG inhibited OVCAR‑3 cell proliferation and migration, potentially mediated via the activation of p38 MAPK and downregulation of the protein expression of MMP2. Thus, the therapeutic potential of EGCG for ovarian cancer requires further investigation.

Downregulation of stathmin is involved in malignant phenotype reversion and cell apoptosis in esophageal squamous cell carcinoma.

Stathmin plays a critical role in the regulation of mitosis and mediates the development of malignant tumors. Here, we investigated the potential role of stathmin in cell cycle and apoptosis in esophageal squamous cell carcinoma (ESCC).

Association between metformin and the risk of gastric cancer in patients with type 2 diabetes mellitus: a meta-analysis of cohort studies

Objectives The objective of this study was to evaluate the association between metformin therapy and the incidence of gastric cancer (GC) in patients with type 2 diabetes mellitus (T2DM). Methods We systemically searched the following databases for studies published between the databases’ dates of inception and Nov. 2016: PubMed, Embase, the Cochrane Library, the Web of Science, and the China National Knowledge Infrastructure (CNKI). Hazard ratios (HR)and corresponding 95% confidence intervals (CIs) for the association between metformin therapy and the incidence of GC in patients with T2DM were the outcome measures assessed in this study. STATA 12.0 (Stata Corporation, College Station, Texas, USA) was used to conduct the statistical analysis. Results A total of seven cohort studies including 591,077 patients met all the criteria for inclusion in the analysis. Our data showed that metformin therapy was associated with a significantly lower incidence of GC in patients with T2DM than other types of therapy (HR=0.763, 95% CI: 0.642˜0.905). Subgroup analysis showed that patients living in Taiwan benefitted more from metformin therapy than patients living in any other region, as metformin significantly decreased the risk of GC in patients living in Taiwan but did not significantly decrease the risk of GC in patients living in other regions (HR=0.514, 95% CI: 0.384-0.688). The results of the present analysis support the idea that metformin facilitates reductions in the risk of T2DM-related GC. Conclusions The risk of GC among patients with T2DM is lower in patients receiving metformin therapy than in patients not receiving metformin therapy.

S100A4 participates in epithelial-mesenchymal transition in breast cancer via targeting MMP2

Numerous studies have shown that S100A4 acquires its metastasis-promoting effects via inducing epithelial-mesenchymal transition (EMT). However, its role and mechanism in EMT in breast cancer had not been clearly elucidated. Herein, we showed that the knockdown of S100A4 expression in breast cancer cell lines, MDA-MB-231 and MDA-MB-468, inhibited not only cell invasion ability greatly, but also the occurrence of EMT significantly. In addition, S100A4 knockdown could also decrease the expression of MMP2, a promoter and a mediator of the EMT processes in cancer. Above all, restoring the expression of MMP2 in MDA-MB-231 and MDA-MB-468 could not only rescue the invasion ability inhibited by knockdown of S100A4, but also reverse the EMT suppressed by knockdown of S100A4. In summary, our results indicated that S100A4 could promote the invasion ability of breast cancer cells via EMT, more importantly, it could participate in EMT via regulating MMP2 in breast cancer. Therefore, S100A4 could be a candidate biomarker for defining breast cancer metastasis and useful target for therapy.

The correlation between DNMT1 and ERα expression and the methylation status of ERα, and its clinical significance in breast cancer

The correlation between the expression of DNA methyltransferase-1 (DNMT1) and estrogen receptor α (ERα), as well as the methylation status of ERα, was analyzed to investigate the clinical significance of DNMT1 and ERα in breast cancer. Substance P immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) were utilized to detect the protein and mRNA expression levels of DNMT1 and ERα in 112 breast cancer and 20 normal breast specimens. Methylation specific PCR was utilized to detect the methylation status of ERα in ERα-positive and -negative breast cancer specimens and 20 normal breast specimens. The results of the present study revealed that DNMT1 protein and mRNA levels were low in normal breast specimens (10.00 and 46.05%, respectively) and ERα-positive breast cancer specimens (15.00 and 48.68%, respectively), compared with increased levels in ERα-negative breast cancer specimens (81.11 and 88.89%, respectively; P<0.05). The methylation rate of ERα was highest in ERα-negative breast cancer specimens (86.11%) compared with normal breast specimens and ERα-positive breast cancer specimens (10.00 and 36.84%, respectively; P<0.05). Positive expression of ERα protein was observed to be associated with progesterone receptor expression (P<0.05), however, no such association was observed for age, menopause state, tumor size, number of positive nodes, Tumor-Node-Metastasis stage or tumor type (P>0.05). The protein and mRNA expression levels of DNMT1 were negatively correlated with ERα expression (P<0.05). DNMT1 expression was positively correlated with methylation of ERα (P<0.05), and was positively correlated with the methylation of CpG islands of ERα, indicating that the detection of DNMT1 expression may be significant for the diagnosis and typing of breast cancer.

miR-106b promotes cell invasion and metastasis via PTEN mediated EMT in ESCC

MicroRNA (miR)-106b serves an essential function in a variety of human cancer types, particularly in the process of invasion and metastasis. However, the function and mechanism of miR-106b in the invasion and metastasis of esophageal squamous cell carcinoma (ESCC) has remained elusive. In the present study, it was demonstrated that miR-106b was upregulated in ESCC tissues and cell lines. Furthermore, miR-106b expression in ESCC tissues was positively associated with lymphatic metastasis. Inhibition of miR-106b in EC-1 and EC9706 cells decreased not only the invasion and metastasis ability but also the proliferation ability of EC-1 and EC9706 cells. In addition, miR-106b had the ability to induce epithelial-to-mesenchymal transition (EMT) in EC-1 and EC9706 cells. In terms of the underlying mechanism, it was revealed that miR-106b promoted the invasion, metastasis and proliferation ability of EC-1 and EC9706 cells by directly targeting phosphatase and tension homolog (PTEN). Furthermore, miR-106b induced EMT in EC-1 and EC9706 cells by suppressing the expression of PTEN. In summary, the present study revealed that miR-106b contributed to invasion and metastasis in ESCC by regulating PTEN mediated EMT. Downregulation of miR-106b may be a novel strategy for preventing tumor invasion and metastasis.

Metformin inhibited esophageal squamous cell carcinoma proliferation in vitro and in vivo and enhanced the anti-cancer effect of cisplatin

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignancy with poor prognosis in China. Chemotherapy now is one of the most frequently used treatments for patients with ESCC in middle or late stage, however the effects were often limited by increased chemoresistance or treatment toxicity. So it is urgent to find new drugs to treat ESCC patients. Metformin with low cost and toxicity has proved to have anti-cancer effects in a numerous cancers, while its role and mechanism in ESCC has seldom been studied. In the present study, we found that metformin exhibited not only an anti-proliferation ability in a dose and time dependent manner but also a proapoptosis effect in a dose dependent manner in ESCC cell line KYSE450. Our in vivo experiment also showed that metformin markedly inhibited KYSE450 xenograft tumors growth compared to those treated with normal saline. What’s more, no obvious toxic reactions were observed. To further explore the underlying mechanism, we found that metformin treatment could significantly damp the expression of 4EBP1 and S6K1 in KYSE 450 cells in vitro and in vivo, furthermore, the p-4EBP1 and p-S6K1 expression in KYSE 450 cells were also inhibited greatly in vitro and in vivo. During the therapy of cancer, in order to overcome side effects, combination therapy was often used. In this paper, we demonstrated that metformin potentiated the effects of cisplatin via inhibiting cell proliferation and promoting cell apoptosis. Taken together, metformin owned the potential anti-cancer effect on ESCC in monotherapy or was combined with cisplatin and these results laid solid basis for the use of metformin in ESCC.