Lipid peroxidation is another potential mechanism besides pore-formation underlying hemolysis of tentacle extract from the jellyfish Cyanea capillata.

This study was performed to explore other potential mechanisms underlying hemolysis in addition to pore-formation of tentacle extract (TE) from the jellyfish Cyanea capillata. A dose-dependent increase of hemolysis was observed in rat erythrocyte suspensions and the hemolytic activity of TE was enhanced in the presence of Ca2+, which was attenuated by Ca2+ channel blockers (Diltiazem, Verapamil and Nifedipine). Direct intracellular Ca2+ increase was observed after TE treatment by confocal laser scanning microscopy, and the Ca2+ increase could be depressed by Diltiazem. The osmotic protectant polyethylenglycol (PEG) significantly blocked hemolysis with a molecular mass exceeding 4000 Da. These results support a pore-forming mechanism of TE in the erythrocyte membrane, which is consistent with previous studies by us and other groups. The concentration of malondialdehyde (MDA), an important marker of lipid peroxidation, increased dose-dependently in rat erythrocytes after TE treatment, while in vitro hemolysis of TE was inhibited by the antioxidants ascorbic acid-Vitamin C (Vc)-and reduced glutathione (GSH). Furthermore, in vivo hemolysis and electrolyte change after TE administration could be partly recovered by Vc. These results indicate that lipid peroxidation is another potential mechanism besides pore-formation underlying the hemolysis of TE, and both Ca2+ channel blockers and antioxidants could be useful candidates against the hemolytic activity of jellyfish venoms.

SPOCD1 promotes the proliferation and metastasis of glioma cells by up-regulating PTX3.

Gliomas are the most prevalent type of primary brain tumors in adults, accounting for more than 40% of neoplasms in the central nervous system. The spen paralogue and orthologue C-terminal domain containing 1 (SPOCD1) has been recently identified and found to discriminate progressive from non-progressive bladder cancers. In this study, we detected high-level of SPOCD1 expression in glioma and its high expression significantly associated with advanced tumor grade and poor prognosis. In vitro assays showed that knockdown of SPOCD1 significantly inhibited cell proliferation and colony formation capacities in U373 and U87 cells. In a xenograft model of glioma, SPOCD1 was also found to inhibit tumor growth. In addition, knockdown of SPOCD1 was shown to inhibit cell migration and invasion in glioma U373 and U87 cells. SPOCD1 positively regulated the expression of Pentraxin 3 (PTX3), whereas overexpression of PTX3 attenuated SPOCD1 knockdown-mediated inhibition of cell proliferation, migration and invasion in glioma cells. Our observations suggest that SPOCD1 promotes the proliferation and metastasis of glioma cells through regulating PTX3. Our data might provide novel evidence for the diagnosis and treatment of glioma in clinic.

Formononetin sensitizes glioma cells to doxorubicin through preventing EMT via inhibition of histone deacetylase 5.

Chemoresistance is a major obstacle to successful chemotherapy for glioma. Formononetin is a novel herbal isoflavonoid isolated from Astragalus membranaceus and possesses antitumorigenic properties. In the present study, we investigated the anti-proliferative effects of formononetin on human glioma cells, and further elucidated the molecular mechanism underlying the anti-tumor property. We found that formononetin enhanced doxorubicin cytotoxicity in glioma cells. Combined treatment with formononetin reversed the doxorubicin-induced epithelial-mesenchymal transition (EMT) in tumor cells. Moreover, we found that formononetin treatment significantly decreased the expression of HDAC5. Overexpression of HDAC5 diminished the suppressive effects of formononetin on glioma cell viability. Furthermore, knockdown of HDAC5 by siRNA inhibited the doxorubicin-induced EMT in glioma cells. Taken together, these results demonstrated that formononetin-combined therapy may enhance the therapeutic efficacy of doxorubicin in glioma cells by preventing EMT through inhibition of HDAC5.

Histone deacetylase 5 promotes the proliferation of glioma cells by upregulation of Notch 1.

Histone deacetylases (HDACs) constitute a family of enzymes that play important roles in the epigenetic regulation of gene expression and contribute to the growth, differentiation and apoptosis of cancer cells. However, the biological function of HDAC5 in glioma cells has not been fully understood. In the present study, we found that the mRNA and protein levels of HDAC5 are increased in human glioma tissues and cell lines. In addition, overexpression of HDAC5 promoted proliferation of glioma cells, as measured by the MTT assay. By contrast, HDAC5 gene silencing using small interfering RNA (siRNA) inhibited cell proliferation. Furthermore, we demonstrated that HDAC5 enhances Notch 1 expression at both the mRNA and the protein level in glioma cell lines. Taken together, these results demonstrated, for the first time to the best of our knowledge, that HDAC5 promotes glioma cell proliferation, and suggest that this effect involves the upregulation of Notch 1. Therefore, our study may provide a novel therapeutic target for treatment of gliomas.