Min Li

Purpose: Glioblastoma is one of the most common malignant cancers worldwide. In our previous work, we have shown that heat shock cognate protein 70 (Hsc70) functions as a positive growth regulator in glioma. We investigated the role of Hsc70 in integrin beta 1 mediated invasion of glioma cells. Methods: In order to investigate whether the down-regulation of Hsc70 would affect the expression of integrin beta 1 subunit, HeLa cells were transiently transfected with Hsc70-AS or pcDNA3.0 vectors and the down-regulation of Hsc70 was confirmed by Western blotting. Human brain glioma U87 cells were stably transfected with Hsc70-AS or pcDNA3.0 vectors to further elucidate the relationship between Hsc70 and integrin beta 1 in human glioma cells. Cellular localization of integrin beta 1 was detected using immunofluorescence confocal microscopy analysis. Results: Here we reported that down-regulation of the expression of Hsc70 in U87 cells by transfection with antisense cDNA specifically increased the expression of cell surface integrin beta 1 without changing its mRNA. Meanwhile, the integrin beta 1 125-kD mature form increased while 105-kD precursor form decreased when Hsc70 was down-regulated. Mechanically, the U87 cells transfected with antisense cDNA of Hsc70 decreased the Golgi localization of integrin beta 1, strengthened its interaction with integrin alpha 5 subunit, and enhanced the adhesion ability to fibronectin (FN) and the phosphorylation level of focal adhesion kinase (FAK). Conclusion: Overall, these results suggested that the down-regulation of Hsc70 expression could promote the expression of cell surface integrin beta 1 and subsequently inhibit glioma invasion phenotype.

Migration and invasion are often recognized as the main reasons for the high recurrence and death rates of glioma and limit the efficacy of surgery and other antitumor therapies. In this study, we found over activation of heat shock cognate protein 70 (Hsc70) in human glioma specimens, which was closely related to glioma grade. We investigated whether Hsc70 induced the migration and invasion of glioma cells. Wound healing and transwell migration assay were used to determine the migration and invasion ability of human glioma U251 and U87 cells, in which the expression of Hsc70 was knocked down by small interfering RNA. Western blot analysis was performed to determine the expression of FAK‐Src signaling in malignant glioma cells. The results showed that Hsc70 deficiency significantly retarded migration and invasion and reduced the phosphorylation of FAK, Src, and Pyk2 in U251 and U87 cells. Overall, our results indicate that the migration and invasion capacity of human brain glioma cells is at least partly induced by Hsc70‐dependent activation of FAK‐Src signaling.

Heat shock cognate protein 70 (Hsc70) is a key mediator for the maintenance of intracellular proteins and regulates cellular activities. And it is elevated in various tumor tissues including glioma, which is closely related to the malignancy and poor prognosis of the tumors. However, the effects of Hsc70 on gliomas and its regulatory mechanism have not yet been elucidated. In the present study, we found that Hsc70 was overexpressed in glioma tissues and cultured glioma cells. Furthermore, Hsc70 expression exhibited positive correlation with the grades of gliomas. Knockdown of Hsc70 could effectively inhibit cell proliferation and increase cell apoptosis. Furthermore, we identified that β4GalT5 was a critical target for Hsc70-mediated anti-glioma effects. Blocking β4GalT5 activity could effectively reverse the anti-tumor effect of Hsc70. Taken together, these data indicate that Hsc70 regulates β4GalT5 levels, and possibly plays a role in cell proliferation and apoptosis of glioma.

Glioblastoma is one of the most aggressive types of brain tumor. The median survival rate of patients with glioblastoma (World Health Organization grade IV) is <15 months. Therefore, there is an urgent requirement for the development of novel and efficient therapeutic agents against glioma. In previous studies, WZY‑321 (10‑hydroxy‑1‑methyl‑8,13b‑dihydro‑5H,7H‑benzo[e]benzofuro[2',3':3,4]pyrido[2,1‑b][1,3]oxazin‑5‑one), a novel evodiamine (Evo) analog, was reported to exhibit enhanced pharmacological properties and improved cytotoxicity against a number of human cancer cell lines compared with Evo. In the current study, the anti‑proliferative effect of WZY‑321 on SHG‑44 and SWO‑38 glioma cells was further studied, and its mechanism of action investigated. The results indicated that WZY‑321 inhibited the proliferation of SHG‑44 cells in a dose‑ and time‑dependent manner by enhancing cellular apoptosis and inducing cell cycle arrest at the G2‑M phase. Treatment of glioma cells with WZY‑321 concomitantly increased the expression levels of microtubule associated protein 1 light chain 3α and Beclin1, indicating enhanced autophagy. Overall, the results of the present study revealed the anti‑proliferative potential of WZY‑321 in glioma cells, thus providing a possible autophagy‑based therapeutic strategy for the treatment of glioblastoma.

MiR-29b inhibits the growth of glioma via MYCN dependent way MiR-29b inhibits the growth of glioma via MYCN dependent way

Gliomas are the most common type of malignant brain tumor. Studies have identified that miR‑15b is negatively correlated with cripto-1 expression in glioma cells, and these molecules serve an important role in cancer development and progression. The current study was undertaken to further examine the association between these two molecules. Fluorescent quantitative PCR confirmed that miR‑15b expression was significantly downregulated in glioma tissue while cripto‑1 expression was significantly increased. Subsequent to transfection with miR‑15b mimics, cripto‑1 expression was significantly suppressed, and dual luciferase reporter assays further demonstrated that miR‑15b regulates cripto‑1 in a targeted manner. Furthermore, miR‑15b inhibited proliferation and invasion, and promoted apoptosis of glioma cells while downregulating the expression of MMP‑2 and MMP‑9. In contrast, cripto‑1 expression had the opposite effects. Co‑transfection with miR‑15b mimics and the cripto‑1 overexpression vector overcame the inhibitory action of miR‑15b on cripto‑1. Therefore, it is suggested that miR‑15b modulates cell growth and invasion through targeted regulation of cripto‑1 expression in glioma cells. This observation may provide novel targets for the prevention and treatment of gliomas.

Aim. To investigate the role and mechanism of miR-15b in the proliferation and apoptosis of glioma.Methods. The miR-15b mimics were transfected into human glioma cells to upregulate the miR-15b expression. Cyclin D1 was determined by both western blotting analysis and luciferase reporter assay. Methylthiazol tetrazolium (MTT) and flow cytometry were employed to detect the cell proliferation, cell cycle, and apoptosis.Results. Overexpression of miR-15b inhibits proliferation by arrested cell cycle progression and induces apoptosis, possibly by directly targeting Cyclin D1. Both luciferase assay and bioinformatics search revealed a putative target site of miR-15b binding to the 3′-UTR of Cyclin D1. Moreover, expression of miR-15b in glioma tissues was found to be inversely correlated with Cyclin D1 expression. Enforced Cyclin D1 could abrogate the miR-15b-mediated cell cycle arrest and apoptosis.Conclusions. Our findings identified that miR-15b may function as a glioma suppressor by targeting the Cyclin D1, which may provide a novel therapeutic strategy for treatment of glioma.