Plexin-B1 is a target of miR-214 in cervical cancer and promotes the growth and invasion of HeLa cells.

Plexin-B1, the receptor for Sema4D, has been reported to trigger multiple and sometimes opposing cellular responses in various types of tumor cells. It has been implicated in the regulation of tumor-cell survival, proliferation, angiogenesis, invasion and metastasis. However, the plexin-B1 gene expression and its regulatory mechanism in cervical cancer remain unclear. The present study shows that plexin-B1 is over-expressed in cervical tumor tissues compared to normal cervical tissues by immunohistochemistry, Western blotting and quantitative RT-PCR. The expression of plexin-B1 is significantly associated with cervical tumor metastasis and invasion according to the analysis of the clinicopathologic data. Plexin-B1 also promotes proliferation, migration and invasion in human cervical cancer HeLa cells. We also found that the plexin-B1 levels are inversely correlated with miR-214 amounts in both cervical cancer tissues and HeLa cells. And miR-214 expression level is also associated with metastasis and invasion of cervical tumor. Furthermore, we demonstrate that plexin-B1 is inhibited by miR-214 through a miR-214 binding site within the 3'UTR of plexin-B1 in HeLa cells. Ectopic expression of miR-214 could inhibit the proliferation capacity, migration and invasion ability of HeLa cells. Our findings suggest that plexin-B1, a target of miR-214, may function as an oncogene in human cervical cancer HeLa cells.

[Correlation between expressions of matrix metalloproteinase-2 & 9 and vasculogenic mimicry in gastrointestinal stromal tumors].

OBJECTIVE: To study the correlation between the expression of matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF) and vasculogenic mimicry (VM) in gastrointestinal stromal tumors (GIST). METHODS: The immunohistochemical staining indices (SI) of MMP-2, MMP-9, VEGF were assessed on specimens of 84 human cases with GIST (21 VM-positive cases). Gelatin zymography analysis of the activity of MMP-2 and MMP-9 activities were performed on another 42 human cases of GIST with fresh tissue (22 VM-positive cases). RESULTS: The staining indices (SI) of MMP-2 and MMP-9 were higher in the VM-positive group (4.10 +/- 2.05 and 3.43 +/- 1.89 respectively) than in the VM-negative group (2.98 +/- 1.97 and 2.38 +/- 1.84 respectively, both P < 0.05); there was no statistic difference in the SI of VEGF between VM-positive and VM-negative group. Gelatin zymography analysis showed that the activity of MMP-2 and MMP-9 were significantly higher in the VM-positive group (3.62 +/- 3.95 and 4.77 +/- 5.29 respectively) than in the VM-negative group (1.26 +/- 1.21 and 2.11 +/- 1.54 respectively, both P < 0.05). CONCLUSION: The expression of MMP-2 and MMP-9 correlates with VM formation in GIST.

Experimental study on the treatment of intracerebral glioma xenograft with human cytokine-induced killer cells.

Objective. To investigate the phenotype changes and proliferation activities of cytokine-induced killer cells (CIKs) and lymphokine-activated killer cells (LAKs) from healthy donor, and the cytotoxicities of CIKs and LAKs to human in vitro glioma cell lines U251 and U87. Therapy of CIK intratumoral injection was evaluated in nude mouse models. Methods. CIK cells were induced from peripheral blood mononuclear cells (PBMC) of healthy donors with multiple cytokines. Phenotype analysis of CIKs and LAKs was performed with flow cytometer (FCM). The specific cytotoxicities of CIKs and LAKs against cell line U251 and U87 were determined by LDH method. After intracerebral injection of CIKs, the distribution of CIKs and the inflammatory reaction of their surrounding brain tissue were observed through continuous pathological sections. In vivo anti-tumor activity of CIKs was evaluated in athymic nude mice with intracerebral xenotransplanted U251 glioma by MRI. Results. Amount of CIKs was increased (49.83+/-2.04) times and double positive cells, CD3(+)/CD56(+) cells, were increased from (3.36+/-1.85%) to (44.07+/-14.14%) with elevated absolute amount over 1000 times after 2 week culture. In vitro experiments demonstrated that compared with LAK, CIKs possessed more obvious cytotoxic activity to U251 and U87. In vivo experiments showed that there was no severe inflammatory reaction in brain tissue. CIKs can markedly inhibit intracranial xenotransplanted glioma growth by intracranial injection (P<0.01). Conclusion. CIKs are a kind of highly effective immune cells which have a strong suppressive effect on growth for in vitro and in vivo glioma. Local injection of CIKs does not produce severe damage to normal brain tissue and is likely to be used in clinical adoptive immunotherapy of intracerebral glioma.

Epigenetic regulation of bone morphogenetic protein-6 gene expression in breast cancer cells.

Bone morphogenetic protein-6 (BMP-6) is closely correlated with tumor differentiation and skeletal metastasis. Our previous research found that BMP-6 gene expression can be activated dose-dependently by estrogen in estrogen receptor positive (ER(+)) breast cancer cell line MCF-7, but not in ER negative (ER(-)) cell line MDA-MB-231. This experiment is designed to investigate the epigenetic regulatory mechanism of the BMP-6 gene expression in breast cancer cell lines MDA-MB-231, MCF-7 and T47D with regard to the methylation status in the 5' flanking region of the human BMP-6 gene. The endogenous level of BMP-6 mRNA in ER(-) cell line MDA-MB-231 was relatively lower than that in ER(+) MCF-7 and T47D cell lines. After the treatment with 5-aza-2'-deoxycytidine (5-aza-dC, especially in the concentration of 10 microM), the BMP-6 mRNA expression in MDA-MB-231 was obviously up-regulated. However, 5-aza-dC treatment failed to regulate the expression of BMP-6 in MCF-7 and T47D cells. Using enzyme restriction PCR (MSRE-PCR), as well as bisulfite sequencing (BSG), methylation of human BMP-6 gene promoter was detected in MDA-MB-231; while in MCF-7 and T47D, BMP-6 gene promoter remained demethylated status. In 33 breast tumor specimens, promoter methylation of BMP-6 was detected by methylation-specific PCR, hypermethylation of BMP-6 was observed in ER negative cases (16 of 16 cases (100%)), while obviously lower methylation frequency were observed in ER positive cases (3 of 17 cases (18%)), indicating that BMP-6 promoter methylation status is correlated with ER status in breast cancer.