Huamei Tang

Long non-coding RNA HOTAIR is a powerful predictor of metastasis and poor prognosis and is associated with epithelial-mesenchymal transition in colon cancer.

Colon cancer is one of the most frequently diagnosed cancer and the third most fatal malignancy worldwide. HOTAIR, a cancer-associated long non-coding RNA (lncRNA), is a powerful biomarker of metastasis and poor prognosis in a diverse group of cancers. Nevertheless, an understanding of how HOTAIR is involved in colon cancer progression is limited. In the present study, we hypothesized that HOTAIR plays a crucial role in colon cancer development. We evaluated the expression of HOTAIR in 120 colon cancer samples, matched adjacent non-tumor mucosa and 32 lymph node metastasis tissues by real-time PCR. Increased HOTAIR expression was significantly correlated with the depth of tumor invasion, lymph node metastasis, organ metastasis, histological differentiation, vascular invasion and advanced tumor stage. Patients with high HOTAIR expression had higher recurrence rates and reduced metastasis-free and overall survival than patients with low HOTAIR expression. Moreover, our findings revealed that HOTAIR had a limited effect on cell proliferation but significantly promoted colon cancer cell migration and invasion in vitro. Depletion of HOTAIR increased the expression of E-cadherin while concomitantly decreasing expression of vimentin and MMP9. Hence, HOTAIR may be another pleiotropic modulator participating in epithelial-mesenchymal transition (EMT). These results indicate that HOTAIR may also be a valuable predictor for colon cancer management; furthermore, this lncRNA may be a potential target for cancer prevention and treatment.

Molecular regulation of constitutive expression of interleukin-8 in human pancreatic adenocarcinoma

Recent studies have shown that interleukin-8 (IL-8) plays an important role in the growth and metastasis of human pancreatic cancer. In the present study, we determined the molecular regulation of constitutive IL-8 expression in human pancreatic cancer cells. Various human pancreatic cancer cell lines were incubated in vitro. Sixty-seven percent of the cell lines constitutively secreted high levels of IL-8, as determined using enzyme-linked immunosorbent assay. Consistently, these cells constitutively expressed high levels of IL-8 mRNA, as determined using Northern blot analysis. To determine the mechanisms of the high steady-state levels of IL-8 mRNA, the IL-8 half-life and transcription rate were measured. There was no significant difference in IL-8 half-life between cells expressing high and low levels of IL-8. However, higher transcription rates and increased IL-8 promoter activity were observed in the cells constitutively expressing high levels of IL-8. Detailed IL-8 promoter analysis using deletion mutation revealed that the region from -85 to -133 bp was essential for the constitutive IL-8 promoter activity. Also, point-mutation analysis indicated that mutation of NF-kappaB, AP-1, or NF-IL-6 binding sites significantly reduced or eliminated the constitutive IL-8 promoter activity. Consistent with the constitutive IL-8 transcription activity, high levels of constitutive NF-kappaB and AP-1 activity were detected in the cells overexpressing IL-8, as determined using electrophoretic mobility shift assay. In addition, transfection of a dominant-negative I-kappaBalpha expression vector (I-kappaBalphaM) inhibited constitutive NF-kappaB activity and IL-8 expression in pancreatic cancer cells. Collectively, our data demonstrated that constitutive NF-kappaB and AP-1 activation contributes to the overexpression of IL-8, which in turn plays an important role in tumor angiogenesis and contributes to the aggressive biology of human pancreatic cancer.

Identification of recurrence-related microRNAs in hepatocellular carcinoma following liver transplantation.

Tumor recurrence‐related microRNAs (miRNAs) in hepatocellular carcinoma (HCC) following orthotopic liver transplantation (OLT) are not clear yet. This study was designed to determine whether altered miRNA expression is associated with HCC recurrence and prognosis following OLT. 18 miRNAs, including 6 up‐regulated and 12 down‐regulated miRNAs were identified by microarray in primary HCC samples of patients who had developed HCC recurrence (n = 5) compared to those with non‐recurrence (n = 5) following OLT by using p < 0.05 as cutoff value. The six most significantly altered miRNAs (fold change ≥ 2: miR‐19a, miR‐886‐5p, miR‐126, miR‐223, miR‐24 and miR‐147) were further confirmed by qRT‐PCR in the remaining 105 HCC samples. In receiver‐operating characteristic curve analysis, this six miRNAs were of high sensitivity and specificity in predicting HCC recurrence. Using Cox regression and risk score analysis, we built a six‐miRNA signature based on their qRT‐PCR readings for the prediction of outcome of HCC following OLT. Kaplan–Meier and Cox proportional regression revealed this six‐miRNA signature was a significant independent predictor of overall survival (log‐rank p = 0.020) and recurrence‐free survival (log‐rank p < 0.001). Finally, the data were further reconfirmed in an independent cohort of 50 patients from another transplant center. In addition, bioinformatics Gene Ontology and pathway analysis were also performed to better understand the critical roles of these miRNAs in HCC recurrence. Our study, in addition to suggesting a different miRNA expression pattern between HCC samples of patients with recurrence and those with non‐recurrence, proposes that this six‐miRNA signature may serve as biomarker for prognosis of HCC patients following OLT.

RUNX3 inhibits the expression of vascular endothelial growth factor and reduces the angiogenesis, growth, and metastasis of human gastric cancer

Purpose: Recent studies indicated that RUNX3 exhibits potent antitumor activity. However, the underlying molecular mechanisms of this activity remain unclear. In the present study, we used a gastric cancer model to determine the effect of RUNX3 expression on tumor angiogenesis. Experimental Design: The effects of increased RUNX3 expression on vascular endothelial growth factor (VEGF) expression in and angiogenic potential of human gastric cancer cells were determined in vitro and in animal models. RUNX3 and VEGF expression was determined in 120 human gastric cancer specimens and their relationship was analyzed. Results:RUNX3 gene transfer suppressed VEGF expression in human gastric cancer cells. Down-regulation of VEGF expression correlated with a significantly impaired angiogenic potential of human gastric cancer cells. Furthermore, RUNX3 restoration inhibited tumor growth and metastasis in animal models, which was consistent with inhibition of angiogenesis as determined by evaluating VEGF expression and tumor microvessel formation. In gastric cancer specimens, loss or decrease in RUNX3 expression inversely associated with increased VEGF expression and elevated microvessel formation. Conclusions: Our clinical and experimental data provide a novel molecular mechanism for the antitumor activity of RUNX3 and may help design effective therapy targeting RUNX3 pathway to control gastric cancer growth and metastasis.

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8–1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study.

The critical role of dysregulated FOXM1-PLAUR signaling in human colon cancer progression and metastasis.

Purpose: The mammalian Forkhead Box (Fox) transcription factor FOXM1 is implicated in tumorigenesis including mouse intestinal cancer. However, the clinical significance of FOXM1 signaling in human colorectal cancer pathogenesis remains unknown. Experimental Design: We investigated FOXM1 expression in 203 cases of primary colon cancer and matched normal colon tissue specimens and explored the underlying mechanisms of altered FOXM1 expression and the impact of this altered expression on colon cancer growth and metastasis using in vitro and animal models of colon cancer. Results: We found weak expression of FOXM1 protein in the colon mucosa, whereas we observed strong FOXM1 expression in tumor-cell nuclei of colon cancer and lymph node metastases. A Cox proportional hazards model revealed that FOXM1 expression was an independent prognostic factor in multivariate analysis. Experimentally, overexpression of FOXM1 by gene transfer significantly promoted the growth and metastasis of colon cancer cells in orthotopic mouse models, whereas knockdown of FOXM1 expression by siRNA did the opposite. Promotion of colon tumorigenesis by FOXM1 directly and significantly correlated with activation of urokinase-type plasminogen activator receptor (PLAUR) expression and elevation of invasion and metastasis. Conclusions: Given the importance of FOXM1 in regulation of the expression of genes key to cancer biology, dysregulated expression and activation of FOXM1 may play important roles in colon cancer progression and metastasis. Clin Cancer Res; 19(1); 62–72. ©2012 AACR.

KLF4-Mediated Negative Regulation of IFITM3 Expression Plays a Critical Role in Colon Cancer Pathogenesis

Purpose:IFITM3, an IFN-inducible gene, is overexpressed in human colorectal cancer. In this study, we sought to determine the clinical significance and underlying mechanisms of its dysregulated expression in human colon tumor specimens and murine models of this disease. Experimental Design: IFITM3 expression in a tissue microarray of tumor and matched normal colon tissue specimens and lymph node metastasis specimens obtained from 203 patients with colon cancer was measured immunohistochemically. Results: IFITM3 was expressed at higher levels in colon tumors and, particularly, nodal metastases than in normal colon tissue. A Cox proportional hazards model showed that IFITM3 expression was an independent prognostic factor for disease-free survival in patients with colon cancer. Knockdown of IFITM3 expression by a specific siRNA significantly suppressed the proliferation, colony formation, migration, and invasion of colon cancer cells in vitro and tumor growth and metastasis in a xenograft model. Restored expression of KLF4, a putative tumor suppressor, downregulated IFITM3 expression in colon cancer cells in vitro. Two KLF4-binding sites in the IFITM3 promoter bound specifically to KLF4 protein in a chromatin immunoprecipitation assay and promoter mutagenesis analyses. Specific deletion of KLF4 led to IFITM3 overexpression in colon mucosa in Villin-Cre+;Klf4fl/fl mice. An inverse correlation between loss of KLF4 expression and IFITM3 overexpression was evident in human colon tumors. Conclusion: These clinical and mechanistic findings indicate that IFITM3 is a direct transcriptional target of KLF4 and that dysregulated KLF4 expression leads to aberrant IFITM3 expression, thus contributing to colon cancer progression and metastasis. Clin Cancer Res; 17(11); 3558–68. ©2011 AACR.

FOXM1 expression predicts the prognosis in hepatocellular carcinoma patients after orthotopic liver transplantation combined with the Milan criteria.

Molecular biomarker has been proposed to improve patient selection and post-transplant prognostication, but rare achievement has been made. In the present study, Forkhead box M1 (FOXM1) expression and its prognostic role have been investigated in hepatocellular carcinoma (HCC) treated by orthotopic liver transplantation (OLT). We found that the notably higher level of FOXM1 in tumors was associated with malignant pathological features of HCC and unfavorable outcome after OLT. The status of FOXM1 expression combined with the Milan criteria could make the prognostication more accurate and may be of particular interest for expanding the criteria in selecting transplant candidates.

Overexpression of Forkhead box M1 protein associates with aggressive tumor features and poor prognosis of hepatocellular carcinoma.

The aim of this study was to detect the expression of the Forkhead box M1 (FOXM1) protein in human hepatocellular carcinoma (HCC) and to associate FOXM1 expression with clinicopathological features of the patients, and predict the prognosis of patients with FOXM1 expression. Surgical tissue specimens from 151 HCC patients were subjected to a tissue microarray construction and immunohistochemistry analysis of FOXM1 and the proliferation marker proliferating cell nuclear antigen (PCNA). The data showed that the FOXM1 protein was expressed in 59.3% of the HCC tissues, which was significantly higher compared to that of the surrounding non-tumorous tissues (23.8%; P<0.001). Moreover, FOXM1 expression was positively correlated with the labeling index of PCNA (P<0.001) in HCC and with aggressive tumor phenotypes, such as larger tumor size, multiple tumors, bilobar involvement, poor tumor cell differentiation, advanced stage and macrovascular invasion (P<0.05). In addition, HCC patients with FOXM1-positive tumors had a poorer recurrence-free and overall survival after hepatectomy than those with FOXM1-negative tumors. Multivariate Cox regression analysis demonstrated that FOXM1 expression was an independent predictor of unfavorable outcome (P<0.05). The data from the current study suggest that FOXM1 may play an important role in HCC progression and could be further evaluated as a prognostic biomarker and potential therapeutic target.

Phospholipase C epsilon plays a suppressive role in incidence of colorectal cancer

In our previous study, we have found that PLCE1 was down-regulated in sporadic colorectal cancer. But the role of PLCE1 in the incidence of colorectal cancer is still not definite. Therefore, in order to validate whether PLCE1 displays a suppressive role, in this study, we examined the expression of PLCE1 in sporadic colorectal cancer with a larger sample size and the effect of PLCE1 overexpression on cancer cell malignant degree. The expression level of PLCE1 in 50 colorectal cancers with their pair-matched normal tissues was measured by RT-PCR, Western blot, and immunohistochemistry. The effect of PLCE1 overexpression on cancer cell malignant degree was measured by MTT assay, plate colony formation assay, soft agar colony formation assay, cell cycle and apoptosis analysis, and xenograft assay. We found that PLCE1 was down-regulated in 42% (21/50) of colorectal cancer tissues compared with pair-matched normal tissues, more frequent in the poor differentiation tumor in patients under 60. Overexpression of PLCE1 significantly inhibited the proliferation of colon cancer cells and degraded its malignant degree. These results suggest that PLCE1 may be involved in the development of sporadic colorectal cancer through its inhibitory effect on cell proliferation. PLCE1 exhibits a suppressive role in incidence of colorectal cancer.