Paxillin expression is closely linked to the pathogenesis, progression and prognosis of gastric carcinomas

MiR-216b regulates the tumorigenesis of gastric cancer by targeting PXN

BACKGROUND

Accumulating evidence has demonstrated that microRNAs (miRNAs) are associated with tumorigenesis. miR-216b can play a vital role in the genesis and development of gastric cancer (GC), and its molecular mechanisms require further elucidation.

METHODS

The biological effects of miR-216b in GC cells were investigated by MTT, transwell assays, and cell cycle. Western blot and luciferase assay were performed to demonstrate the direct binding of miR-216b on PXN 3'UTR. Furthermore, MTT, colony formation assays, transwell assays, and flow cytometry analysis, as well as xenograft mice model, were used to measure the effects of miR-216b-PXN on GC cell proliferation, migration, and invasion indicated by in vitro and in vivo.

RESULTS

Our results showed that miR-216b acted as a tumor suppressor in GC progression. miR-216b overexpression suppressed GC cell proliferation, migration, and invasion in vitro. Luciferase reporter assays identified paxillin (PXN) as a novel target gene of miR-216b. PXN overexpression could partially rescue miR-216b-induced the inhibitory effects in GC cells. Besides, overexpression of miR-216b contributed to the activation of PI3K/AKT signaling via partly regulating PXN in GC cells.

CONCLUSIONS

The above results showed that miR-216b could offer a novel therapeutic avenue by targeting PXN in GC.

Silencing lncRNA XIST exhibits antiproliferative and proapoptotic effects on gastric cancer cells by up-regulating microRNA-132 and down-regulating PXN

The present study aims to elucidate the potential therapeutic role of lncRNA XIST in gastric cancer through regulation of microRNA-132 (miR-132) and paxillin (PXN) expression. The study employed 65 gastric cancer tissue specimens and SGC7901 cell lines. Our results demonstrated that expression of lncRNA XIST and PXN was significantly elevated while the expression of miR-132 was significantly reduced in gastric cancer tissues. Dual-luciferase, RNA pull-down and RIP assays demonstrated that lncRNA XIST up-regulated the PXN expression by competitively binding to miR-132. Moreover, silencing of lncRNA XIST and up-regulation of miR-132 could suppress tumor formation ability, cell proliferation and migration, but enhanced apoptosis in gastric cancer. However, the overexpression of PXN achieved the opposite tumor-promotive effect. Meanwhile, rescue experiments suggested that silencing of lncRNA XIST could reverse the tumor-promotive effect exerted by either miR-132 inhibitor or PXN. Taken together, the present study demonstrates lncRNA XIST as a novel oncogenic lncRNA in gastric cancer, highlighting its therapeutic role in this disease.

The Extracellular Matrix: An Accomplice in Gastric Cancer Development and Progression

The extracellular matrix (ECM) is a dynamic and highly organized tissue structure, providing support and maintaining normal epithelial architecture. In the last decade, increasing evidence has emerged demonstrating that alterations in ECM composition and assembly strongly affect cellular function and behavior. Even though the detailed mechanisms underlying cell-ECM crosstalk are yet to unravel, it is well established that ECM deregulation accompanies the development of many pathological conditions, such as gastric cancer. Notably, gastric cancer remains a worldwide concern, representing the third most frequent cause of cancer-associated deaths. Despite increased surveillance protocols, patients are usually diagnosed at advanced disease stages, urging the identification of novel diagnostic biomarkers and efficient therapeutic strategies. In this review, we provide a comprehensive overview regarding expression patterns of ECM components and cognate receptors described in normal gastric epithelium, pre-malignant lesions, and gastric carcinomas. Important insights are also discussed for the use of ECM-associated molecules as predictive biomarkers of the disease or as potential targets in gastric cancer.

Diverse Expression of IL-32 in Diffuse and Intestinal Types of Gastric Cancer

Introduction

Gastric cancer (GC) represents one of the most common cancers worldwide, frequently diagnosed at advanced stages with poor prognosis, indicating on need for new diagnostic and prognostic markers. The aim of the study was to determine the expression of IL-32, proinflammatory and angiogenic mediators, in patients with diffuse and intestinal gastric cancer and the relationship with clinicopathological aspects.

Material and Methods

The tissue samples of diffuse and intestinal types of tumor of 70 patients with gastric cancer were analyzed. Expression of IL-32, VEGF, IL-17, and CD31 was measured by immunohistochemistry.

Results

IL-32 expression was significantly lower in tissue samples from patients with diffuse type of gastric cancer that is also a severe and more progressive form (TNM stages III and IV, poor histological differentiation, and higher nuclear grade III). Expression of IL-17 was also decreased in patients with diffuse type of gastric cancer. Microvascular density was diminished in diffuse type of gastric cancer.

Conclusions

Downregulated expression of IL-32 in tumor tissue of patients with diffuse type of gastric cancer may implicate on its role in limiting ongoing proinflammatory and proangiogenic processes. This emphasizes on unrecognized role of IL-32 in biology of diffuse type of gastric cancer.

Semisynthetic oleanane triterpenoids inhibit migration and invasion of human breast cancer cells through downregulated expression of the ITGB1/PTK2/PXN pathway

This paper reports a study on the role of two synthetic derivatives of oleanolic acid (OA), HIMOXOL and Br-HIMOLID, in the regulation of cell migration and invasion and the underlying molecular mechanisms of breast cancer cells. The effect of the compounds on four breast cancer cell lines (MCF7, MDA-MB-231, MDA-MB-468, and T-47D) and also on noncancerous breast cells, MCF-12A, was reported. The compounds had no effect on the migration of MCF-12A cells. However, both the derivatives revealed a higher cytotoxicity than the maternal compound OA, and in sub-cytotoxic concentrations, they decreased the migration of MCF7, MDA-MB-231, and MDA-MB-468 breast cancer cells and also the invasion of MCF7 and MDA-MB-231 cells; although, the derivatives had no effect on the migration and invasion of T-47D cells. Both the derivatives of OA inhibited the cell migratory and invasive abilities of breast cancer cells by downregulating the expressions of ITGB1, PTK2, and PXN genes and by decreasing the phosphorylation status and the level of its respective proteins (integrin β1, FAK, and paxillin, respectively). This study is the first to report the antimigratory and anti-invasive activities of HIMOXOL and Br-HIMOLID in breast cancer cells.

Paxillin functions as an oncogene in human gliomas by promoting cell migration and invasion

Background

Paxillin is implicated in tumorigenesis, progression and aggressive phenotypes of various malignancies, highlighting its functions in cellular adhesion, migration and survival. However, the roles of paxillin in human gliomas remain unclear. The aim of this study was to evaluate the clinical implication of paxillin expression in patients with gliomas and its biological function in glioma cells.

Patients and methods

Expression levels of paxillin gene and protein, respectively, were detected by quantitative real-time reverse transcription polymerase chain reaction, Western blot and immunohistochemistry analyses in 120 pairs of glioma and matched nontumorous brain tissues. The associations between paxillin expression and various histopathological features of glioma patients were also statistically evaluated. Then, the functions of paxillin in cell migration and invasion of glioma cell lines were determined by transwell assays in vitro.

Results

The expression levels of both paxillin gene and protein in glioma tissues were markedly higher than those in matched nontumorous brain tissues. Notably, paxillin overexpression was significantly associated with the grade of malignancy (P<0.05). Moreover, the enforced expression of paxillin promoted the migration and invasion of glioma cells, while the loss of paxillin expression efficiently suppressed cell migration and invasion of glioma cell lines.

Conclusion

Our data suggest that paxillin may function as an oncogene and its overexpression may be closely correlated with tumor progression of human gliomas by modulating tumor cell motility, implying the potential of paxillin as a new therapeutic target for glioma intervention.

MicroRNA-212 functions as an epigenetic-silenced tumor suppressor involving in tumor metastasis and invasion of gastric cancer through down-regulating PXN expression

Altered expression of paxillin (PXN) is closely linked to the pathogenesis progression, metastasis and prognosis of different malignancies including gastric cancer (GC). Epigenetic silencing of tumor-suppressive microRNAs (miRNAs) is a crucial component of the mechanism underlying activation of oncogenes in tumor. To screen for epigenetically silenced miRNAs which target PXN in GC, we performed bioinformatics algorithms and real-time PCR analysis, and identified miR-212 as the optimum candidate gene. A luciferase reporter gene assay validated that miR-212 directly targets the 3'UTR region of PXN. Importantly, miR-212 levels were inversely correlated with PXN expression in GC cell lines and clinical tumor tissues. The use of miR-212 minics decrease PXN mRNA and protein level in GC cell lines. Moreover, low expression of miR-212 and its promoter hypermethylation were causally related and were associated with aggressive tumor phenotype and adverse prognosis in GC. Restoring mir-212 expression by exogenous mirprecursor molecules transfection or reexpression of endogenous miR-212 treated by 5-aza-2'-deoxycytidine (5-aza) can exert similar effect that reduce GC cells invasion and metastasis abilities in vitro by interacting PXN gene. In addition, 5-aza-induced PXN reduction could be partically blocked by miR-212 inhibitor, resulting in a reversal of weankening cell migration and invasion ability of 5-aza. A rescue experiment and a loss-of-function experiment in vitro and vivo showed that PXN restoration rescues migration and invasion phenotype in miR-212 overexpressed GC cell lines and PXN knockdown blocks GC cells migration and invasion in the presence miR-212 inhibitors. Taken together, our results clearly show that overexpression of PXN induced by methylationsuppressed miR-212 promotes tumor metastasis and invasion, and regulation of miR-212 expression may be a novel therapeutic strategy for gastric cancer.