Ubiquitin-like modifier activating enzyme 2 promotes cell migration and invasion through Wnt/ß-catenin signaling in gastric cancer.

AIM: To investigate the function and mechanism of ubiquitin-like modifier activating enzyme 2 (Uba2) in progression of gastric cancer (GC) cells. METHODS: Uba2 level in patients with GC was analyzed by Western blotting and immunohistochemistry. MTT and colony formation assays were performed to examine cell proliferation. Flow cytometry was used for cell cycle analysis. Wound healing and Transwell assays were conducted to examine the effects of Uba2 on migration and invasion. Expression levels of cell cycle-related proteins, epithelial-mesenchymal transition (EMT) biomarkers, and involvement of the Wnt/ß-catenin pathway was assessed by Western blotting. Activation of the Wnt/ß-catenin pathway was confirmed by luciferase assay. RESULTS: Uba2 expression was higher in GC than in normal tissues. Increased Uba2 expression was correlated with tissue differentiation, Lauren's classification, vascular invasion, and TNM stage, as determined by the analysis of 100 GC cases (P < 0.05). Knock-down of Uba2 inhibited GC cell proliferation, induced cell cycle arrest, and altered expression of cyclin D1, P21, P27, and Bcl-2, while up-regulation of Uba2 showed the opposite effects. The wound healing and Transwell assays showed that Uba2 promoted GC cell migration and invasion. Western blotting revealed alterations in EMT biomarkers, suggesting the role of Uba2 in EMT. Furthermore, the luciferase reporter assay indicated the involvement of the Wnt/ß-catenin signaling pathway as a possible modulator of Uba2 oncogenic functions. CONCLUSION: Uba2 plays a vital role in GC cell migration and invasion, possibly by regulating the Wnt/ß-catenin signaling pathway and EMT.

UBA2 promotes proliferation of colorectal cancer.

Small ubiquitin­like modifier proteins are involved in tumorigenesis; however, the potential effects and functions of the family member ubiquitin­like modifier­activating enzyme 2 (UBA2) on colorectal cancer are not clear. The present study aimed to examine the effects of UBA2 on the proliferation of colorectal cancer cells in vitro and in vivo. The mRNA and protein expression levels of UBA2 in patients with colorectal cancer were measured by reverse transcription­quantitative polymerase chain reaction and immunohistochemistry, respectively. UBA2 expression levels in colorectal cancer tissues were significantly increased compared with the paracancerous normal tissues. The expression of UBA2 was also associated with higher stage colorectal cancer and poor prognosis. MTT and colony formation assays were used to examine proliferation in colorectal cancer cell lines. Flow cytometry was performed to examine the effects of UBA2 on the cell cycle and apoptosis of colorectal cancer cell lines and protein expression levels were examined by western blotting. Athymic nude mice were used to examine the ability of transfected colorectal cancer cells to form tumors in vivo. Downregulation of UBA2 inhibited the proliferation of colorectal cancer cell lines in vitro and in vivo through the regulation of cell cycle associated protein expression and apoptosis. Furthermore, downregulation of UBA2 decreased the expression levels of cyclin B1, B­cell lymphoma-2, phosphorylated protein kinase B and E3 ubiquitin­protein ligase MDM2 in colorectal cancer cells, whereas the expression levels of p21 and p27 were increased. UBA2 was demonstrated to serve an essential role in the proliferation of colorectal cancer and may be used as a potential biomarker to predict prognosis and as a therapeutic target in colorectal cancer.

Association of matrix metalloproteinase (MMP)-2 and -9 expression with extra-gastrointestinal stromal tumor metastasis.

Matrix metalloproteinase (MMP)-2 and MMP-9 are important proteases involved in invasion and metastasis of various tumors. Extra-gastrointestinal stromal tumors (EGISTs) are rare neoplasms. This study was performed to assess MMP-2 and MMP-9 expression in EGIST tissue samples for association with clinicopathological data from the patients. Twenty-one surgical EGIST tissue specimens were collected for analysis of MMP-2 and MMP- 9 expression using immunohistochemistry. MMP-2 and MMP-9 proteins were expressed in all of the epithelial cell types of EGISTs, whereas they were only expressed in 75% of the spindle cell type, although there was no statistically significant difference (p>0.05). Expression of MMP-2 and MMP-9 proteins was associated with tumor size, mitotic rate, tumor necrosis, and distant metastasis (p<0.05). MMP-2 expression was linked with MMP-9 levels (p<0.05). However, there was no correlation between MMP-9 expression and age, sex, primary site, or cell morphology in any of these 21 EGIST patients (p>0.05). Moreover, expression of MMP-2 and MMP-9 proteins increased with the degree of EGIST risk. This study provided evidence of an association of MMP-2 and MMP-9 expression with advanced EGIST behavior.

Diagnostic significance of DOG-1 and PKC-θ expression and c-Kit/PDGFRA mutations in gastrointestinal stromal tumours.

OBJECTIVE: To investigate discovered on gastrointestinal stromal tumor (GIST)-1 (DOG-1) and protein kinase C-θ (PKC-θ) expression in a series of GISTs and determine the sensitivity, specificity, and diagnostic value of these two antigens. METHODS: Immnunohistochemistry (IHC) was used to detect CD117, DOG-1, PKC-θ, CD34, Ki-67, α-smooth muscle actin (SMA), S100, and Desmin expression in 147 GISTs and 51 non-GISTs. c-Kit gene (exons 9, 11, 13, and 17) and platelet-derived growth factor receptor-alpha (PDGFRA) gene (exons 12 and 18) mutations were also detected. RESULTS: About 94.5% GISTs were CD117 positive, 96% were DOG-1 positive, and 90.5% were PKC-θ positive. DOG-1 had a specificity of 100%, while CD117 and PKC-θ had a specificity of 90% and 80%, respectively. There was no significant difference between DOG-1 and PKC-θ expressions when compared to CD117 expression. In 30 out of 42 (71.5%) GISTs, a c-Kit gene mutation was found, and in 3 out of 42 cases (7%), PDGFRA was mutated. Wild-type c-Kit/PDGFRA genes accounted for 21.5% (9/42). Most c-Kit gene mutations were found to be located at exon 11, mainly as in-frame deletions. Mutations in exon 9 were all missense mutations. Most PDGFRA gene mutations were found in exon 18, codon 842. c-Kit gene mutations in exons 13 and 17, and the PDGFRA gene mutation in exon 12 were not detected. CONCLUSIONS: Compared to CD117, DOG-1 is a biomarker with higher sensitivity and specificity. The combination of CD117 and DOG-1 can be used to improve the diagnosis of GIST. Although PKC-θ has a lower specificity than DOG-1, it can be a useful biomarker, especially in CD117(-) and/or DOG-1(-) cases.

[Detection of antigen-receptor gene rearrangement clonality for diagnosis of lymphoma].

This study was aimed to investigate the significance of detecting the antigen-receptor gene rearrangement clonality in the diagnosis of lymphoma. Paraffin-embedding and HE staining of samples from 31 patients with lymphomas were performed for morphologic observation by light microscope. Immunophenotype was analyzed by the immunohistochemistry (IHC) method. The clonality of antigen-receptor gene rearrangement was detected by BIOMED-2 Assay Kit. The results showed that among the 31 cases, 12 cases were suspected to be T-cell lymphoma, 1 case was suspected to be T-cell reactive hyperplasia, and 16 cases were suspected to be B-cell lymphoma, 2 cases were B-cell reactive hyperplasia. The detection results showed that the positivity of Ig gene rearrangement clonality was 94.44% (17/18), the positivity of TCR gene rearrangement clonality was 92.31% (12/13), the other two cases were negative. Finally, 12 cases were diagnosed to be T-cell lymphoma and 17 cases were B-cell lymphoma. The other two cases were reactive lymphoid proliferations. And the positivity rate in the 31 patients with lymphomas was 93%. It is concluded that the detection of antigen-receptor gene rearrangement clonality is a useful assistant method in the diagnosis of lymphoma.

[Expression of dendritic cell marker CD21 is a positive prognostic factor in diffuse large B-cell lymphoma].

OBJECTIVE: To analyze CD21 expression in diffuse large B cell lymphoma (DLBCL) and to explore its relationship with the clinicopathological characteristics and prognosis. METHODS: The clinical data from 80 DLBCL patients who were treated in First Hospital of Jilin University from June 2005 to September 2011 were retrospectively analyzed. The cases were subjected to immunohistochemical staining (SP method) for Ki-67, CD20, CD79a, CD3, CD43, CD5, cyclin D1, bcl-2, CD10, bcl-6, GCET-1, FOXP-1 and MUM-1 protein expression in the tumor tissue. Immunohistochemistry was also used to detect CD21 expression in the tumor tissue. SPSS 18.0 was used to analyze the relationship between CD21 expression and various clinical factors, and the relationship between various clinical factors including CD21 and overall survival. RESULTS: In the patients aged under 60 years, the incidence of CD21(+) lymphoma (64.0%, 16/25) was significantly higher than that of CD21(-) lymphoma (38.2%, 21/55). There were more CD21(+) lymphoma patients who were at clinical stages I-II (52.0%, 13/25) than patients with CD21(-)lymphomas (23.6%, 13/55). There were also more CD21(+) lymphoma patients (68.0%, 17/25) having less than two extranodal sites involvement than CD21(-)lymphoma patients (41.8%, 23/55). In addition, there were more CD21(+) lymphoma patients with IPI 0-2 (68.0%, 17/25) than CD21(-)lymphoma patients (41.8%, 23/55). There were more CD21(+) lymphoma patients with GCB subtype (60.0%, 15/25) than CD21(-)lymphoma patients (23.6%, 13/55). Death related to DLBCL was less in CD21(+) lymphoma patients (32.0%, 8/25) than CD21(-) lymphoma patients (56.4%, 31/55). Univariate analysis showed that these clinical pathological characteristics affected the overall survival of DLBCL patients, including age, ECOG score, LDH, extranodal involvement, IPI index, CD21 expression, treatment option and efficacy (P < 0.05) . Cox multivariate analysis showed that ECOG score, LDH, extranodal involvement, CD21 expression were closely related to prognosis, and the difference was statistically significant (P < 0.05). Among the 80 patients, the overall survival (OS) of CD21(+) lymphoma patients was significantly higher than that of CD21(-) lymphoma patients. CONCLUSIONS: The expression of CD21 is associated with young age at onset, early clinical stage, small number of involvement and low IPI index. The OS and median overall survival of CD21(+) lymphoma patients are significantly higher than those of CD21(-) patients. CD21 expression, ECOG score, LDH, extranodal involvement are independent prognostic factors in DLBCL, and in particular, the expression of CD21 is more significant in the prognosis of DLBCL patients.