Liucun Gao

Ectopic expression of MiR-125a inhibits the proliferation and metastasis of hepatocellular carcinoma by targeting MMP11 and VEGF.

Background Studies have been shown that miR-125a plays an important role in carcinogenesis, however, the role of miR-125a in hepatocellular carcinoma (HCC) remains elusive. Methodology/Principal Real time-PCR (qRT-PCR) was performed to test the significance of miR-125a in HCC. Ectopic expression of miR-125a was used to test the influences of miR-125a on proliferation and metastasis of HCC cells in vitro and in vivo. Predicted target genes of miR-125a were determined by dual-luciferase reporting, qRT-PCR, and western blot (WB) analyses. Then immunohistochemical staining (IHC) was used to detect the expression of target genes, and the correlations and prognostic values of miR-125a and its target genes were also investigated. Conclusions/Significance Decreased miR-125a was observed in both HCC tissues and cell lines, and associated with patients’ aggressive pathologic features. Up-regulating miR-125a significantly inhibited the malignant phenotypes by repressing the expression of matrix metalloproteinase 11 (MMP11) and vascular endothelial growth factor A (VEGF-A) both in vitro and in vivo. Furthermore, miR-125a expression was inversely correlated with both MMP11 and VEGF-A expression in HCC tissues. Inhibiting miR-125a could increase both MMP11 and VEGF-A expression, and RNA interference targeting MMP11 or VEGF-A mRNA could rescue the loss of miR-125a functions. MiR-125a inhibits the proliferation and metastasis of HCC by targeting MMP11 and VEGF-A. Up-regulation of miR-125a might be a promising approach and a prognostic marker for HCC.

Identification of cancer stem cells in vincristine preconditioned SGC7901 gastric cancer cell line

Cancer stem cells (CSCs), or tumor initiating cells, are a subpopulation of cancer cells with self‐renewal and differentiation properties. However, there has been no direct observation of the properties of gastric CSCs in vitro. Here we describe a vincristine (VCR)‐preconditioning approach to obtain cancer stem‐like cells (CSLCs) from the gastric cancer cell line SGC7901. The CSLCs displayed mesenchymal characteristics, including the up‐regulated mesenchymal markers Snail, Twist, and vimentin, and the down‐regulated epithelial marker E‐cadherin. Using a Matrigel‐based differentiation assay, CSLCs formed 2D tube‐like and 3D complex lumen‐like structures, which resembled differentiated gastric crypts. The characteristic of cellular differentiation was also found by transmission electron microscopy and up‐regulation of gastrointestinal genes CDX2 and SOX2. We further showed that CSLCs could self‐renew through significant asymmetric division compared with parent cells by tracing PKH‐26, BrdU, and EDU label‐retaining cells. In addition, these CSLCs also increased expression of CD44, CD90, and CXCR4 at the mRNA level, which was identified as novel targets. Furthermore, drug sensitivity assays and xenograft experiments demonstrated that the cells developed multi‐drug resistance (MDR) and significant tumorigenicity in vivo. In summary, gastric CSCs were identified from VCR‐preconditioned SGC7901 cell line, characterized by high tumorigenicity and the capacity for self‐renewal and differentiation. J. Cell. Biochem. 113: 302–312, 2012.

Association between Helicobacter pylori infection and the risk of colorectal neoplasia: a systematic review and meta‐analysis

The existing evidence on the relationship between Helicobacter pylori infection and the risk of colorectal neoplasia is inconsistent. We conducted a systematic review with a meta‐analysis to explore this relationship and to determine whether the relationship varies according to the study characteristics.

Overexpression of a novel gene gankyrin correlates with the malignant phenotype of colorectal cancer.

Gankyrin, a small and highly conserved protein which is identical to the p28 gene product, was found to be related with the malignant phenotypes in liver and esophageal carcinoma. However, the roles of gankyrin in colorectal carcinoma (CRC) are still unknown. In the present study, the gankyrin mRNA and protein expression in human CRC cell lines and clinical tissue samples were evaluated and correlated with clinicopathological features. Possible mechanisms by which gankyrin regulates the malignant phenotype of CRC cells were also investigated. The results demonstrated that gankyrin was obviously overexpressed in CRC tissues and cell lines compared to controls, and gankyrin expression was correlated with TNM stages and metastasis of CRC. Overexpression of gankyrin by PhkitNeo-hGankyrin plasmid transfected into Lovo cells could promote the cell proliferation and tumorigenicity. This finding was further strengthened by experiments that suppressing gankyrin expression by siRNA exerted the opposite effects on CRC cells SW620. In addition, our present study showed that the co-expression of cyclinD1 and β-catenin were positive correlation with the alteration of gankyrin expression. This data suggested that gankyrin played significant roles in the pathogenesis of human CRC, and might be an important therapeutic target for CRC.

MiR-199a Regulates Cell Proliferation and Survival by Targeting FZD7

A growing amount of evidence indicates that miRNAs are important regulators of multiple cellular processes and, when expressed aberrantly in different types of cancer such as hepatocellular carcinoma (HCC), play significant roles in tumorigenesis and progression. Aberrant expression of miR-199a-5p (also called miR-199a) was found to contribute to carcinogenesis in different types of cancer, including HCC. However, the precise molecular mechanism is not yet fully understood. The present study showed that miR-199a is frequently down-regulated in HCC tissues and cells. Importantly, lower expression of miR-199a was significantly correlated with the malignant potential and poor prognosis of HCC, and restoration of miR-199a in HCC cells led to inhibition of the cell proliferation and cell cycle in vitro and in vivo. Furthermore, Frizzled type 7 receptor (FZD7), the most important Wnt receptor involved in cancer development and progression, was identified as a functional target of miR-199a. In addition, these findings were further strengthened by results showing that expression of FZD7 was inversely correlated with miR-199a in both HCC tissues and cells and that over-expression of miR-199a could significantly down-regulate the expression of genes downstream of FZD7, including β-catenin, Jun, Cyclin D1 and Myc. In conclusion, these findings not only help us to better elucidate the molecular mechanisms of hepatocarcinogenesis from a fresh perspective but also provide a new theoretical basis to further investigate miR-199a as a potential biomarker and a promising approach for HCC treatment.

SOX2, a predictor of survival in gastric cancer, inhibits cell proliferation and metastasis by regulating PTEN

Inconsistent results of SOX2 expression have been reported in gastric cancer (GC). Here, we demonstrated that SOX2 was progressively downregulated during GC development via immunochemistry in 755 human gastric specimens. Low SOX2 levels were associated with pathological stage and clinical outcome. Multivariate analysis indicated that SOX2 protein expression served as an independent prognostic marker for GC. Gain-and loss-of function studies showed the anti-proliferative, anti-metastatic, and pro-apoptotic effects of SOX2 in GC. PTEN was selected as SOX2 targets by cDNA microarray and ChIP-DSL, further identified by luciferase assays, EMSA and ChIP-PCR. PTEN upregulation in response to SOX2-enforced expression suppressed GC malignancy via regulating Akt dephosphorylation. PTEN inhibition reversed SOX2-induced anticancer effects. Moreover, concordant positivity of SOX2 and PTEN proteins in nontumorous tissues but lost in matched GC specimens predicted a worse patient prognosis. Thus, SOX2 proved to be a new marker for evaluating GC outcome.

Ribosomal protein L6 promotes growth and cell cycle progression through upregulating cyclin E in gastric cancer cells

Our previous study revealed that human ribosomal protein L6 (RPL6) was upregulated in multidrug-resistant gastric cancer cells and over-expression of RPL6 could protect gastric cancer cells from drug-induced apoptosis. The present study was designed to explore the role of RPL6 in tumorigenesis and development of gastric cancer. The expression of RPL6 in gastric cancer tissues and normal gastric mucosa was evaluated by immunohistochemical staining. It was found RPL6 was expressed at a higher level in gastric cancer tissues than that in normal gastric mucosa. RPL6 was then genetically overexpressed or knocked down in human immortalized gastric mucosa epithelial GES cells. It was demonstrated that upregulation of RPL6 accelerated the growth and enhanced in vitro colony forming ability of GES cells whereas downregulation of RPL6 showed adverse effects. Moreover, over-expression of RPL6 could promote G1 to S phase transition of GES cells. It was further evidenced that upregulation of RPL6 resulted in elevated cyclin E expression while downregulation of RPL6 caused decreased cyclin E expression in GES cells. Taken together, these data indicated that RPL6 was overexpressed in human gastric cancer and its over-expression could promote cell growth and cell cycle progression at least through upregulating cyclin E expression.

Nuclear expression of Twist promotes lymphatic metastasis in esophageal squamous cell carcinoma.

Twist-1 protein (also called Twist) has been suggested to be involved in tumor epithelial-mesenchymal transition (EMT) related progression, however, the mechanism by which twist promotes lymph node metastasis is not fully understood. In the present study, we found that nuclear twist expression is clearly correlated with lymph node (LN) metastasis as determined by immunohistochemistry (IHC). A highly invasive EC109 cell subline, EC109-P, was established by repeated in vitro transwell isolations for the cell model. Immunofluorescence (IF) assay demonstrated that nuclear twist expression was markedly higher in the highly invasive EC109-P cell line when compared with EC109 and EC9706 cells. Based on our cell model, the function and mechanism by which twist regulates LN metastasis in ESCC was investigated. The results showed that the overexpression of Twist could significantly increase the invasion and VEGF-C expression of EC9706 cells, whereas the knockdown of twist expression results in the opposite effects. This finding was further strengthened by the results of the analysis of co-expression of twist and VEGF-C by IHC in ESCC clinical samples. In summary, our study indicates that nuclear twist plays an important role in ESCC lymphatic metastasis by increasing the expression of VEGF-C. The combination of twist and VEGF-C detection could be a reliable prediction of LN metastasis in ESCC.

R-Flurbiprofen Reverses Multidrug Resistance, Proliferation and Metastasis in Gastric Cancer Cells by p75NTR Induction†

Nonsteroidal anti-inflammatory drugs (NSAIDs) can inhibit cell growth and metastasis, and induce cell apoptosis in cancerous cells. They have been shown to reduce incidence and mortality of gastric cancer by an unknown mechanism. NSAIDs often exert their effects by Cox-2 inhibition, and Cox-2 is overexpressed in gastric cancer cells. Nevertheless, when gastric cancer cells were treated with different NSAIDs, the non-Cox-2-inhibiting R-flurbiprofen was most effective at reducing proliferation of gastric cancer cells in vitro. R-Flurbiprofen prevented the metastatic characteristics of gastric cancer cells in vitro, and reduced tumor size and metastasis in vitro, when gastric cancer cells were injected into nude mice. R-Flurbiprofen also affected multidrug resistance, increasing the sensitivity of resistant gastric cancer cells to chemotherapeutic agents. Mechanistically, R-flurbiprofen was found to have pleiotropic effects, changing levels of cell cycle factors like Cyclin D1 and CKD4, apoptotic protwins like caspase3 and Bcl-2, and protwins that affect metastasis, like metalloproteases. Consistent with reports on other cancer cell types, NSAID treatment with R-flurbiprofen increased levels of the tumor suppressor neurotrophin receptor (p75(NTR)) in gastric cancer cells. The anticancer effects of R-flurbiprofen were found to require induction of p75(NTR) via the p38 signaling pathway, suggesting a possible mechanism of action.

A retrospective analysis on the diagnostic value of ultrasound-guided percutaneous biopsy for peritoneal lesions.

BackgroundRoutine examinations have a low specificity and a low positive rate for the diagnosis of peritoneal lesions. This study aimed to evaluate the diagnostic value and safety of ultrasound-guided percutaneous peritoneal lesion biopsies in patients with ascites and/or abdominal distension with unclear causes.MethodsA retrospective analysis was performed in 153 consecutive patients with ascites and/or abdominal distension with unclear causes. All of the patients showed abnormalities of the peritoneum or greater omentum after ultrasonography, and underwent ultrasound-guided percutaneous biopsies using a Bard auto-biopsy gun with 18- or 16- gauge biopsy needles.ResultsThe success rate of the procedures was 100% (153/153) and the satisfaction rate of the tissue specimens in the biopsy was 91.5% (140/153). A specific histopathological diagnosis was made in 142 out of 153 patients, with an overall diagnostic accuracy of 92.8%. Among the diagnosed patients, 62 were peritoneal metastatic adenocarcinoma, 49 were peritoneal tuberculosis, 11 were peritoneal malignant mesothelioma, 8 were chronic peritoneal infections, 7 were pseudomyxoma peritonei, and 5 were primary peritoneal lymphoma. Only 11 patients did not get a pathologic diagnosis due to the lack of sufficient tissue specimen. No serious complications occurred.ConclusionsUltrasound-guided percutaneous biopsy could be a simple, safe and accurate diagnostic method in patients with ascites and/or abdominal distension with unclear causes.