Mutant TP53 enhances the resistance of glioblastoma cells to temozolomide by up-regulating O6-methylguanine DNA-methyltransferase
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The “gain of function” of mutant TP53 is an important determinant in human tumor development and progression. This study aimed to investigate the possible mechanism of mutant TP53 inducing temozolomide resistance in glioblastoma cells. Three established human glioma cell lines, T98G, U87, and U138, were chemoresistant cells. The mRNA of cells was sequenced to confirm the status of TP53. Synthetic small interfering RNA (siRNA) was used to knock down TP53 in cells. TP53 mRNA was detected “silenced” by reverse transcriptase-polymerase chain reaction (RT-PCR) in five consecutive days. Viable cell survival was measured when these cells were exposed to temozolomide or semustine in step-up concentrations. The expression of O6-methylguanine DNA-methyltransferase (MGMT) at mRNA level was also determined. T98G, U87, and U138 cells were resistant to temozolomide. T98G and U138 cells expressed mutant-type TP53 with positive MGMT, while U87 cell expressed wild-type TP53 with negative MGMT. TP53-siRNA knocked down TP53 effectively (P = 0.021) in five consecutive days. Knockdown of mutant TP53 in T98G and U138 cells led to a fivefold increase in chemosensitivity to temozolomide, but not semustine. Knockdown of wild TP53 in U87 cell did not affect the chemoresistance. In addition, mutant TP53 knockdown induced a dramatic decrease of MGMT expression (P = 0.0000034). TP53 mutation decreases the chemosensitivity of malignant gliomas to temozolomide. This “gain of function” in drug resistance may be obtained by increasing MGMT expression.
KeywordsDrug resistance Glioblastoma Mutation RNA interference Tumor suppressor protein p53
Conflict of interest
The authors declare that they have no conflict of interests.
- 1.Stupp R, Hegi ME, Mason WP, van den Bent MJ, Taphoorn MJ, Janzer RC, Ludwin SK, Allgeier A, Fisher B, Belanger K, Hau P, Brandes AA, Gijtenbeek J, Marosi C, Vecht CJ, Mokhtari K, Wesseling P, Villa S, Eisenhauer E, Gorlia T, Weller M, Lacombe D, Cairncross JG, Mirimanoff RO et al (2009) European Organisation for Research and Treatment of Cancer Brain Tumour and Radiation Oncology Groups, National Cancer Institute of Canada Clinical Trials Group. Effects of radiotherapy with concomitant and adjuvant temozolomide versus radiotherapy alone on survival in glioblastoma in a randomised phase III study: 5-year analysis of the EORTC-NCIC trial. Lancet Oncol 10:459–466PubMedCrossRefGoogle Scholar
- 2.Mirimanoff RO, Gorlia T, Mason W, Van den Bent MJ, Kortmann RD, Fisher B, Reni M, Brandes AA, Curschmann J, Villa S, Cairncross G, Allgeier A, Lacombe D, Stupp R (2006) Radiotherapy and temozolomide for newly diagnosed glioblastoma: recursive partitioning analysis of the EORTC 26981/22981-NCIC CE3 phase III randomized trial. J Clin Oncol 24:2563–2569PubMedCrossRefGoogle Scholar
- 3.Hegi ME, Diserens AC, Gorlia T, Hamou MF, de Tribolet N, Weller M, Kros JM, Hainfellner JA, Mason W, Mariani L, Bromberg JE, Hau P, Mirimanoff RO, Cairncross JG, Janzer RC, Stupp R (2005) MGMT gene silencing and benefit from temozolomide in glioblastoma. N Engl J Med 352:997–1003PubMedCrossRefGoogle Scholar
- 22.Foroutan B, Ali Ruf A, Jerwood D, Anderson D et al (2007) In vitro studies of DNA damage and its repair in cells from NHL patients with different TP53 mutant protein status, resistant (TP53(+)) and sensitive (TP53(−)) to cancer chemotherapy. J Pharmacol Toxicol Methods 55:58–64PubMedCrossRefGoogle Scholar
- 23.Groenendijk FH, Taal W, Dubbink HJ, Haarloo CR, Kouwenhoven MC, van den Bent MJ, Kros JM, Dinjens WN (2011) MGMT promoter hypermethylation is a frequent, early, and consistent event in astrocytoma progression, and not correlated with TP53 mutation. J Neurooncol 101:405–417PubMedCrossRefGoogle Scholar
- 24.Weisz L, Damalas A, Liontos M, Karakaidos P, Fontemaggi G, Maor-Aloni R, Kalis M, Levrero M, Strano S, Gorgoulis VG, Rotter V, Blandino G, Oren M (2007) Mutant TP53 enhances nuclear factor kappaB activation by tumor necrosis factor alpha in cancer cells. Cancer Res 67:2396–2401PubMedCrossRefGoogle Scholar