Difference in the Inhibitory Effect of Temozolomide on TJ905 Glioma Cells and Stem Cells.

Feng Jin,Hao Zhang,Lei Zhao,Quan-Min Nie,Guang-Kui Han,Song Feng,Ling-Sheng Kong,Hua-Rong Li,Xian-Yun Qin,Ran Zhang,Gen-Hua Li

doi:10.3389/fneur.2017.00474

Abstract

This study aims to determine the difference in the inhibitory effect of temozolomide (TMZ) on TJ905 glioma cells and stem cells. TJ905 cancer stem cells were isolated. Livin is a member of the inhibitor of apoptosis protein family. The TJ905 cells and cancer stem cells were transfected with a Livin-shRNA and negative-shRNA, respectively, and then treated with TMZ. At 48 h post-transfection, a cell counting kit 8 assay, flow cytometry, and real-time qPCR were performed to detect cell proliferation, the cell cycle, and the expression of the Caspase-3, -7, and -9 mRNAs, respectively. As a result, the suppressive effect of TMZ on TJ905 cells was more significant than its effect on TJ905 cancer stem cells. TMZ exerted an inhibitory effect on the growth of TJ905 glioma cells by arresting them at G0/G1 phase and arresting cancer stem cells at S phase in a dose-dependent manner. TMZ inhibited Livin mRNA expression and increased the expression of the Caspase-3, -7, and -9 mRNAs. Low Livin mRNA expression induced high levels of Caspase-3, -7, and -9 expressions, thus promoting the apoptosis of both TJ905 cells and cancer stem cells in response to TMZ treatment. The TJ905 cells transfected with the Livin-shRNA were more sensitive to TMZ, whereas the TJ905 glioma stem cells transfected with the Livin-shRNA showed no significant changes in their sensitivity to TMZ. In conclusion, the Livin gene may play an important role in the resistance mechanisms of TJ905 glioma cells and cancer stem cells. However, Livin had a more distinct role in TMZ resistance, cell proliferation, and the cell cycle in TJ905 glioma cells than in cancer stem cells.

Highlights

Glioma is the most common intracranial malignant tumor
This study aims to explore the role of the anti-apoptotic gene Livin in the effect of TMZ on the proliferation and drug resistance of glioma stem cells, offering a new idea to solve drug resistance in glioma
Immunofluorescence staining for nestin was negative, but immunofluorescence staining for GFAP was strongly positive (Figure 1E), and β-tubulin staining was positive (Figure 1F), indicating that glioma stem cells had differentiated

Summary

Introduction

Glioma is the most common intracranial malignant tumor. Radiation, and chemotherapy have achieved great progress, glioma is still difficult to completely cure [1]. The challenge lies in recurrence of the tumor and drug resistance to chemotherapy. Studies identifying new methods and ideas that overcome the limitations of current therapies and prolong the survival of patients suffering from gliomas are required [2]. Studies of cancer stem cells have highlighted their roles in tumorigenesis and the development of cancer drug resistance [3]. The theory postulates that cancer stem cells display

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