Clinical Study Of Malignant Glioma And Effects Of Anti-transferrin Receptor Antibody On Glioma Cells In Vitro

Part Ⅰ. Prognostic analysis of malignant gliomaMalignant gliomas are the most common primary intracranial tumor in adult, and their infiltrative behaviors result in the poor prognosis of patitents. The integrative therapies consisting of surgery, radiotherapy and chemotherapy are now advocated clinically. The survival time of patients is also not improved greatly even if these treatments are all taken action. Therefore, to find more effective therapeutic means is the goal neurosurgeons seek persistently for. In the part Ⅰ. of this study, the cases of malignant gliomas treated in our department were analyzed retrospectively. The treatment strategies for managing malignant glioma and the prognosis of patients were investigated to find out the prognostic factors, and to provide the clue on finding out more powerful treatment.Aim:To investigate the treatment strategies for malignant glioma and the prognosis of patients, and to analyze the significant prognostic factors of malignant glioma.Methods:The clinical data of68patients with malignant glioma, treated in our department in recent decade, were analyzed retrospectively. The patients were divided into four groups according to different treatments:group A (surgery only), group B (surgery concomitant with chemotherapy), group C (surgery concomitant with radiotherapy), and group D (surgery concomitant with chemoradiotherapy). The survival rates of the whole cases and each group were calculated by using Kaplan-Meier method. Multivarates analysis was performed by Cox regression model, and the univariate analysis by Log-rank test.Result:There were43males and25females in our study, aged of16to71years old, and the mean age was48.8±13.6years old. The number in each group was respectively13,6,28, and21. Pathological exam disclosed anaplastic astrocytoma (AA) in34cases, anaplastic oligodendroglioma (AO) in10and glioblastoma in23. The overall survival rate of1-,2-, and5year were54.2%,41.9%, and16.2%, respectively. The postoperative survival time in whole cases was29.4±5.18months, and the medial survival time was17months. The mean postoperative survival time in each group was respectively12.3±2.67,9.8±1.8,32±6.77, and21.9±2.51months. The mean postoperative survival time in patients histologically diagnosed AA and AO (WHO grade Ⅲ) was35.2±6.75months, whereas it was13.7±2.1months in glioblastoma (WHO grade Ⅳ), and the differences between them was significant (P=0.009). The Cox regression model showed that age, pathological grade of tumor and resection extent were independent prognostic factors (P<0.05), and age, pathological grade of tumor and therapy were the prognostic factors in univariate analysis (P<0.05).Conclusion:The prognosis of patients with malignant glioma is still poor, especially in glioblastoma (WHO grade Ⅳ). The integrative treatment strategies of surgery concomitant with chemoradiotherapy could prolong the postoperative survival time, and improve the prognosis of patients. Part Ⅱ. Effects of anti-transferrin receptor antibody on human glioma cells in vitroTransferrin receptor (TfR) is a cell membrane-associated glycoprotein involved in the cellular uptake of iron and in the regulation of cell growth. TfR is expressed more abundantly in malignant tissues than their normal counterparts, and the elevated levels of TfR expression is correlated with tumor grade and stage or prognosis. Therefore, TfR deserves attention as a relevant target for cancer therapy, especially for antibody-based therapy against tumors. Various in vitro and in vivo studies demonstrated that anti-TfR antibodies were active against tumor cells. However, results of clinical trials showed that the therapy of anti-TfR antibodies, as monotherapy, may be limited in patients with advanced cancer. In this study, we mainly investigate the anti-tumor effects and mechanisms of anti-TfR mAb in combination with chemotherapeutic drug on human glioma cells cells in vitro. These studies will provide a basis for further developing TfR-targeted chemoimmunotherapy for glioma.Aim:To investigate anti-tumor effects of anti-TfR mAb alone and in combination with chemotherapeutic drug on glioma cells (U251) in vitro, which provides a basis to further develop TfR-targeted chemoimmunotherapy for cancer.Methods:The expression of TfR in tumor tissues and U251cells were detected by immunohistochemical and western blot analysis. The apoptosis of U251cells after treated with anti-TfR mAb and chemotherapeutic drugs alone or the combinations were evaluated by FCM with PI-Annexin Ⅴ staining. The proliferation of U251cells after treated with anti-TfR mAb and chemotherapeutic drugs alone or the combinations were evaluated by FCM with CFSE staining. The cell cycle of U251cells after treated with anti-TfR mAb and chemotherapeutic drugs alone or the combinations were evaluated by FCM with PI staining.Results:High expression of TfR on glioma specimens and U251cells were detected, and the expression level was positively correlated with tumor grade. When anti-TfR mAb was used in combination with chemotherapeutic drugs on tumor cells, the combined inhibition was greater than that of chemotherapeutic drug alone and dramatically induced apoptosis and S phase arrest of tumor cells. Analyses of the nature of anti-TfR mAb/chemotherapeutic drug interactions demonstrated that synergistic interactions were observed for anti-TfR mAb in combination with Nimustine. In addition, results of PI-AnnexinV staining demonstrated that the anti-TfR mAb/chemotherapeutic drug combinations induced more apoptosis cells than that of chemotherapeutic drug alone.Conclusion:anti-TfR mAb alone suppressed the proliferation of tumor cells, induced apoptosis and S phase arrest of tumor cells. Down-regulation of the expression levels of surface TfR on tumor cells might be one of the mechanisms contributing to anti-tumor effects of anti-TfR mAb. In combination treatment with nimustine, anti-TfR mAb enhanced the cytotoxicity of chemotherapy drugs on glioma cells in a synergistic manner, and induced more dead cells, mainly apoptosis cells, than that of each chemotherapeutic drug alone.