Decreased expression of LASS2 is associated with worse prognosis in meningiomas.

Homo sapiens longevity assurance homolog 2 of yeast LAG1 (LASS2) has been indicated to have a critical role in various tumors. In the study, we aimed to evaluate the LASS2 expression level in prognostic significance and compare it with commonly used biomarkers: Ki-67, p53 and progesterone receptor (PR) for patients with meningiomas. Firstly, 50 fresh tissues and 143 paraffin-embedded meningiomas samples were analyzed for LASS2 expression by quantitative PCR and immunohistochemistry (IHC), respectively. Subsequently, LASS2 immunostaining was evaluated for its clinical significance. Furthermore, Correlations of LASS2 expression with common biomarkers were assessed. Both PCR and IHC results showed LASS2 was downregulated in high-grade meningiomas in comparison with that of grade I or normal brain (all P < 0.01). IHC results demonstrated LASS2 intensity distribution (ID) score was significantly correlated with tumor size, brain invasion, tumor recurrence and clinical course (all P < 0.01), whereas no correlation of LASS2 ID score with sex or Simpson grade. Moreover, lower LASS2 ID score was strikingly associated with shorter overall and progression-free survival (P < 0.01). Pearson's analysis revealed the ID score was significantly reversely associated with Ki-67 and p53 but not with PR. More importantly,multivariate analyses revealed that LASS2 was an independent prognostic factor (P < 0.05). To our knowledge, it is the first time to investigate the expression of LASS2 and identify it as a potential biomarker for prognosis in meningiomas.

Expression of RACGAP1 in high grade meningiomas: a potential role in cancer progression.

Recently, Rac GTPase-activating protein 1 (RACGAP1) has been shown to have a critical role in various tumors. The aim of the present study was to investigate the expression of RACGAP1 in human meningiomas and to compare these results with the clinicopathological parameters. Thirty-two cases, classified as 13 World Health Organization grade I (40.6 %), 10 grade II (31.3 %) and 9 grade III (28.1 %) primary meningiomas, were selected from our pathological files. Clinico-pathological data, including survival data, were also available. RACGAP1 expression in the meningiomas was measured by real-time quantitative PCR and western blot. Our results showed the level of RACGAP1 expression in grade III meningioma is higher than that of grade I. Higher levels of RACGAP1 mRNA were significantly correlated with tumor size, higher Simpson grade, histological type and clinical course (P < 0.05). Furthermore, the level of RACGAP1 expression mRNA was positively correlated with MIB-1 labeling index in different meningiomas tissue (r(2) = 0.3237, P = 0.0007). Additionally, Kaplan-Meier curves demonstrated a significantly worse survival in patients with high levels of RACGAP1 mRNA (P = 0.008). In conclusion, these findings suggest that RACGAP1 may be used as a potential predictor for tumor proliferative and patient prognosis in meningiomas.

Association between laminin γ1 expression and meningioma grade, recurrence, and progression-free survival.

BACKGROUND: Laminins are central components of basement membranes and play important roles in cell adhesion, proliferation, and migration. However, the role of laminins in tumor progression has not been thoroughly investigated in meningiomas. OBJECTIVE: The aim of the present study is to evaluate the expression of laminin γ1 in various grades of meningiomas in Chinese patients. METHODS: In the current study, clinical and pathological data for 32 meningioma patients with various tumor grades were collected. The expression of laminin γ1 in each tumor was assessed by using quantitative real-time polymerase chain reaction (qPCR), Western blot and immunohistochemical analysis and was correlated with the meningioma grade, tumor recurrence and patient survival. Patient prognoses were attained and the progression-free survival was calculated based on the Kaplan-Meier method. A two-sided probability cutoff of 0.05 was chosen for statistical significance. RESULTS: A total of 32 meningioma patients with various pathological subtypes (WHO grade I: 13, grade II: 10 and grade III: 9) were enrolled in this study. The qPCR results showed that laminin γ1 mRNA expression was significantly higher in grade III meningiomas than in grade I meningiomas (p < 0.05), although there was no significant difference in laminin γ1 expression between grade II and grade I meningiomas (p > 0.05). Western blot and immunohistochemistry analysis confirmed that the expression of laminin γ1 protein was relatively higher in grade III meningiomas when compared with grade I meningiomas. Higher levels of laminin γ1 expression in meningiomas are associated with a significantly shorter tumor recurrence time (p < 0.05) and a decreased patient survival time (p < 0.05). CONCLUSIONS: Our results suggest that laminin γ1 is associated with meningioma grades and could play a role in enhancing tumor invasion. Laminin γ1 could be used as a predictor for meningioma recurrence and patient survival. Furthermore, laminin γ1 may represent a druggable molecular target for future therapies for tumors that overexpress this marker.

[LASS2 interacts with V-ATPase and inhibits cell growth of hepatocellular carcinoma].

Homo sapiens longevity assurance homologue 2 (LASS2) is a novel gene isolated from a human liver cDNA library by our laboratory, and it is a human homologue of the yeast longevity assurance gene LAG1 (Saccharomyces cerevisiae longevity assurance gene). According to our previous results, LASS2 could interact with subunit c of vacuolar type H(+)-ATPase (V-ATPase), and the overexpression of LASS2 could inhibit the cell growth of a human hepatocellular carcinoma (HCC) cell line, SMMC-7721. In order to understand the role of the interaction between LASS2 and V-ATPase in HCC cell growth, we transiently transfected plasmid pCMV-HA2-LASS2 into HCCLM3, a HCC cell line without the significant expression of endogenous LASS2. The pH-sensitive fluorescence probes, BCECF and BCECF-AM, were used to measure the intracellular and extracellular H(+) concentrations of HCCLM3 cells respectively. The effect of LASS2 gene on apoptosis was evaluated with Annexin-V/FITC and propidium iodide (PI) by flow cytometry. Western blot was used to detect cytochrome c (Cyt c) in the cytosol and mitochondria, as well as pro-caspase-3 in cytosol. The results showed that the cell growth of LASS2-transfected HCCLM3 cells was significantly inhibited compared with that of the mock control. LASS2 transfection increased intracellular H(+) concentration of HCCLM3 cells, while decreased extracellular H(+) concentration. Moreover, LASS2 transfection significantly enhanced the apoptosis of HCCLM3 cells. In LASS2-transfected cells, the amounts of Cyt c increased in the cytosol, while decreased in the mitochondria. Meanwhile, the expression of pro-caspase-3 in the cytosolic extracts was decreased. These results implicate that LASS2 gene might increase intracellular H(+) of HCC cells via the interaction with V-ATPase, thereby inducing cell apoptosis through mitochondrial pathway.

Adenosine A2a receptor induces GDNF expression by the Stat3 signal in vitro.

Adenosine A2a receptor (A2aR) is believed to play a role in a number of physiological responses and pathological conditions. Our group has shown previously that A2aR-activated astrocytes occurred following oxygen-glucose deprivation. However, the relationship between A2aR and neurotrophins is poorly understood. Here, we investigate the effect of A2aR on glial cell line-derived neurotrophic factor (GDNF) expression in rat brain astrocyte-2 (RBA-2) cells by quantitative PCR and western blot. We established a stable A2aR-overexpressing cell line and found that A2aR induced GDNF expression both at mRNA and protein levels. A2aR-selective antagonist Sch58261 decreased GDNF expression in a dose-dependent manner with increased activation of Stat3. The Stat3 inhibitor reversed the effect of Sch58261 on GDNF expression. Therefore, these data indicate that A2aR induces GDNF expression by the Stat3 pathway, which provides a new insight into the function of A2aR in cerebral ischemia and neuroprotection.

Chromosome 1p/19q status combined with expression of p53 protein improves the diagnostic and prognostic evaluation of oligodendrogliomas.

BACKGROUND: Our previous study confirmed that oligodendrogliomas had higher frequency of chromosome 1p/19q deletion. In order to improve the diagnostic criteria and to predict the prognosis of oligodendroglioma patients, the status of chromosome 1p/19q deletion, the methylation of O(6)-methylguanine-DNA methyltransferase (MGMT), and the expression of p53 protein were evaluated and investigated in relation to patients' outcomes. METHODS: Methylation of MGMT in 73 cases was analyzed by nested methylation-specific PCR (MSP). The levels of MGMT and p53 protein were tested with immunohistochemistry. Pearson's chi-square test and Fisher's exact test were used. Multivariate and Kaplan-Meier analysis were performed to determine patients' outcomes. RESULTS: Both oligodendrogliomas and astrocytic gliomas exhibited frequent methylation of MGMT. However, the results of MSP did not completely correspond to that of the immunohistochemical staining for MGMT. The expression of p53 protein was more frequently observed in patients without a 1p or 19q deletion in anaplastic oligodendrogliomas (P = 0.032, 0.025). In low-grade oligodendrogliomas, methylation of MGMT was more frequent in patients with 1p/19q deletion than in patients with 1p/19q intact (P = 0.038). Patients with oligodendrogliomas with 1p/19q loss of heterozygosity and p53-negative showed a longer progression-free survival. CONCLUSION: Detection of chromosome 1p/19q status combined with p53 protein immunohistochemistry might be beneficial to improve the pathological diagnosis and to determine the prognosis of patients with oligodendrogliomas.

Adenosine A2a receptor induced gliosis via Akt/NF-kappaB pathway in vitro.

Gliosis is characterized by increased expression of glial fibrillary acidic protein (GFAP) and astroglial proliferation, although the mechanism underlying the process is still largely undefined. This study explores the role of the adenosine A2a receptor (A2aR) in gliosis after ischemia-like injury in a rat astrocyte cell line transfected with A2aR. A2aR transfection enhanced GFAP expression and cell proliferation. A2aR-selective antagonist Sch58261 decreased GFAP expression in a dose- and time-dependent manner with increased activation of Akt, and induced activation of NF-kappaB. An Akt inhibitor reversed the effect of Sch58261. These results suggest that the effect of A2aR on gliosis is related to the Akt/NF-kappaB signal pathway.