Suppression of miR-221 inhibits glioma cells proliferation and invasion via targeting SEMA3B

BACKGROUND: Gliomas are the most common primary tumors in the central nervous system. Due to complicated signaling pathways involved in glioma progression, effective targets for treatment and biomarkers for prognosis prediction are still scant. RESULTS: In this study we revealed that a new microRNA (miR), the miR-221, was highly expressed in the glioma cells, and suppression of miR-221 resulted in decreased cellular proliferation, migration, and invasion in glioma cells. Mechanistic experiments validated that miR-221 participates in regulating glioma cells proliferation and invasion via suppression of a direct target gene, the Semaphorin 3B (SEMA3B). The rescue experiment with miR-221 and SEMA3B both knockdown results in significant reversion of miR-221 induced phenotypes. CONCLUSION: Taken together, our findings highlight an unappreciated role for miR-221 and SEMA3B in glioma.

Receptor activator of NF-kappaB ligand enhances the activity of macrophages as antigen presenting cells

Receptor activator of NFkappaB ligand (RANKL) is known as a key regulator of osteoclastogenesis. However, the fact that fibroblasts and periodontal ligament cells express RANKL in response to bacterial substances, suggests that RANKL may have evolved as a part of the immunity to infection. As RANKL increases the survival and activity of dendritic cells, it may have similar effects on macrophages. To address this issue, we studied the effect of RANKL on various functions of macrophages using mouse bone marrow derived macrophages. RANKL enhanced the survival of macrophages and up-regulated the expression of CD86. RANKL-treated macrophages showed increased allogeneic T cell activation and phagocytic activity compared to control cells. In addition, RANKL increased the expression of TNFalpha, MCP-1, and IL-6 but not of IL-10, IL-12, IFN-gamma, and iNOS. Collectively, RANKL augmented the activity of macrophages especially as antigen presenting cells, suggesting its new role in immune regulation.

Role of macrophage-colony stimulating factor and osteoclast differentiation factor in osteoclastogenesis of bone marrow derived stem cells.

Macrophage colony stimulating factor (M-CSF) and osteoclast differentiation factor (ODF) regulate osteoclastogenesis in vivo. Regulation of osteoclast development in vitro by these cytokines has been reported in the present study. Simultaneous addition of ODF and M-CSF during initiation of bone marrow culture inhibited osteoclastogenesis. However, delayed addition of ODF (three days after initiation of the culture) resulted in dramatic increase in phenotypically and functionally mature osteoclast cells. Delayed addition of ODF beyond day three decreased osteoclastogenesis. Further, removal of M-CSF as early as day three inhibited ODF-induced osteoclastogenesis. These studies provided evidence for the importance of co-ordinated regulation of osteoclastogenesis by M-CSF and ODF.

Triptolide sensitizes lung cancer cells to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by inhibition of NF-kappa B activation

TNF-related apoptosis-inducing ligand (TRAIL/Apo- 2L), a newly identified member of the TNF family promotes apoptosis by binding to the transmembrane receptors (TRAIL-R1/DR4 and TRAIL-R2/ DR5). TRAIL known to activate NF-kappa B in number of tumor cells including A549 (wt p53) and NCI- H1299 (null p53) lung cancer cells exerts relatively selective cytotoxic affects to the human tumor cell lines without much effect on the normal cells. We set out to identify an agent that would sensitize lung cancer cells to TRAIL-induced apoptosis through inhibition of NF-kappa B activation. We found that triptolide, an oxygenated diterpene extracted and purified from the Chinese herb Tripterygium wilfordii sensitized A549 and NCI-H1299 cells to TRAIL-induced apoptosis through inhibition of NF-kappa B activation. Pretreatment with MG132 which is a well-known NF-kappa B inhibitor by blocking degradation of Ikappa B alpha also greatly sensitized lung cancer cells to TRAIL-induced apoptosis. Triptolide did not block DNA binding of NF-kappa B activated by TRAIL as in the case of TNF-alpha. It has been already proven that triptolide blocks transactivation of p65 which plays a key role in NF-kappa B activation. These observations suggest that triptolide may be a potentially useful drug to enhance TRAIL-induced tumor killing in lung cancer.

Macrophage colony-stimulating factor promotes the survival of osteoclast precursors by up-regulating Bcl-XL

Macrophage colony-stimulating factor (M-CSF) is known as one of the factors essential for osteoclast development. In the present study, we examined effects of M-CSF on the apoptotic pathway of osteoclast precursors and their underlying molecular mechanisms. Osteoclast precursors underwent apoptosis in the absence of M-CSF, even in the presence of receptor activator of NF-kB ligand (RANKL). Active caspase-3 and -9 were detected in the osteoclast precursors and treatments of precursors with their specific inhibitors (Z- DEVD-FMK and Z-LEHD-FMK) decreased the apoptosis. M-CSF decreased apoptosis in a dose-dependent manner with decreasing in active caspases-3 and -9 levels and up-regulating Bcl-XL. Those effects of M-CSF on inhibiting apoptosis of osteoclasts precursor by regulating anti-apoptotic signals was more effective when combined with RANKL. These results demonstrate that M-CSF acts as a survival factor for the osteoclast precursors. Furthermore, it is believed that the apoptosis of osteoclast precursors may be involved in the activation of caspase-9 and that M-CSF may promote their survival through Bcl-XL-induced inhibition of caspase-9 activation.

Correlation between membrane glycoprotein and detergent dissected membrane protein in the assessment of LMIF: a report of 51 ALA cases.

Assessment of 51 amoebic liver abscess cases for leukocyte migration inhibition factor released using membrane glycoprotein and detergent dissected membrane protein (DDMP) of axenic Entamoeba histolytica (NIH:200). Lymphokines release by T lymphocytes in response to purified amoebic membrane glycoprotein (PAMG) against whole amoebic lysate (WAL), dissect out protein against whole amoebic lysate and membrane glycoprotein against dissected protein was tested by leukocyte migration inhibition test on blood samples from proved amoebic liver abscess cases. A significant increase was noted in the release of lymphokines and 100% positivity was observed with both PAMG and DDMP compared to 78% with whole amoebic lysate. The difference between means leukocyte migration indices of the membrane glycoprotein and whole amoebic lysate, detergent dissected protein and whole amoebic lysate with regards to release LMIF were found to be highly significant (P < 0.001), (P < 0.005) respectively. But insignificant difference and very much similarity was noted between the means of membrane glycoprotein and dissect out protein sensitized T lymphocytes with regards to lymphokine release in vitro. This shows the patients had high degree of leukocyte sensitized to pure amoebic membrane glycoprotein and detergent dissected membrane protein compared to whole amoebic lysate. These findings indicate that detergent dissected protein has similar antigenicity with membrane glycoprotein in elicitation cell mediated immune response in amoebic liver abscess cases.