MicroRNA-125b-2 confers human glioblastoma stem cells resistance to temozolomide through the mitochondrial pathway of apoptosis.

MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate protein expression by cleaving or repressing the translation of target mRNAs. miR-125b, one of the neuronal miRNAs, was recently found to be necessary for stem cell fission and for making stem cells insensitive to chemotherapy signals. Temozolomide (TMZ) is a promising chemotherapeutic agent for treating glioblastomas. However, resistance develops quickly and with a high frequency. Given the insensitivity of some glioblastomas to TMZ and the hypothesis that glioma stem cells cause resistance to drug therapy, exploring the functions and mechanisms of miR-125b action on TMZ-treated glioblastoma stem cells would be valuable. In this study, we found that miR-125b-2 is overexpressed in glioblastoma multiforme tissues and the corresponding stem cells (GBMSC); downregulation of miR-125b-2 expression in GBMSC could allow TMZ to induce GBMSC apoptosis. Additionally, the expression of the anti-apoptotic protein Bcl-2 was decreased after the TMZ+miR-125b-2 inhibitor treatment, while the expression of the proapoptotic protein Bax was increased. Further research demonstrated that the induction of apoptosis in GBMSC is also associated with increased cytochrome c release from mitochondria, induction of Apaf-1, activation of caspase-3 and poly-ADP-ribose polymerase (PARP). Taken together, these results suggest that miR-125b-2 overexpression might confer glioblastoma stem cells resistance to TMZ.

[1]  Seryun Kim,et al.  PNA-based antisense oligonucleotides for micrornas inhibition in the absence of a transfection reagent. , 2010, Oligonucleotides.

[2]  Lei Shi,et al.  MiR-21 protected human glioblastoma U87MG cells from chemotherapeutic drug temozolomide induced apoptosis by decreasing Bax/Bcl-2 ratio and caspase-3 activity , 2010, Brain Research.

[3]  Zhongwu Chen,et al.  Autophagy induced by valproic acid is associated with oxidative stress in glioma cell lines. , 2010, Neuro-oncology.

[4]  Lei Shi,et al.  MiR-125b is critical for the suppression of human U251 glioma stem cell proliferation , 2010, Brain Research.

[5]  T. Chambers,et al.  Cyclin-Dependent Kinase 1-Mediated Bcl-xL/Bcl-2 Phosphorylation Acts as a Functional Link Coupling Mitotic Arrest and Apoptosis , 2009, Molecular and Cellular Biology.

[6]  S. Oh,et al.  A highly effective and long-lasting inhibition of miRNAs with PNA-based antisense oligonucleotides , 2009, Molecules and cells.

[7]  H. Ng,et al.  Glioblastoma stem cells resistant to temozolomide-induced autophagy. , 2009, Chinese medical journal.

[8]  Xu Ma,et al.  MiR-125b Expression Affects the Proliferation and Apoptosis of Human Glioma Cells by Targeting Bmf , 2009, Cellular Physiology and Biochemistry.

[9]  O. Mirochnitchenko,et al.  Ischemia-reperfusion-inducible protein modulates cell sensitivity to anticancer drugs by regulating activity of efflux transporter. , 2009, American journal of physiology. Cell physiology.

[10]  A. T. Freitas,et al.  Current tools for the identification of miRNA genes and their targets , 2009, Nucleic acids research.

[11]  Hyun Seok Song,et al.  Metronomic treatment of temozolomide inhibits tumor cell growth through reduction of angiogenesis and augmentation of apoptosis in orthotopic models of gliomas. , 2006, Oncology reports.

[12]  Angelo L. Vescovi,et al.  Brain tumour stem cells , 2006, Nature Reviews Cancer.

[13]  K. Hess,et al.  Autophagic cell death of malignant glioma cells induced by a conditionally replicating adenovirus. , 2006, Journal of the National Cancer Institute.

[14]  P. Cartron,et al.  The small organic compound HA14-1 prevents Bcl-2 interaction with Bax to sensitize malignant glioma cells to induction of cell death. , 2006, Cancer research.

[15]  K. Livak,et al.  Real-time quantification of microRNAs by stem–loop RT–PCR , 2005, Nucleic acids research.

[16]  H. Ruohola-Baker,et al.  Stem cell division is regulated by the microRNA pathway , 2005, Nature.

[17]  Kwang-Soo Kim,et al.  Depletion of Human Micro-RNA miR-125b Reveals That It Is Critical for the Proliferation of Differentiated Cells but Not for the Down-regulation of Putative Targets during Differentiation* , 2005, Journal of Biological Chemistry.

[18]  D. Misailidou,et al.  Randomized phase II study of temozolomide and radiotherapy compared with radiotherapy alone in newly diagnosed glioblastoma multiforme. , 2005, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[19]  S. Katiyar,et al.  Silymarin induces apoptosis primarily through a p53-dependent pathway involving Bcl-2/Bax, cytochrome c release, and caspase activation. , 2005, Molecular cancer therapeutics.

[20]  N. Banik,et al.  Dexamethasone protected human glioblastoma U87MG cells from temozolomide induced apoptosis by maintaining Bax:Bcl-2 ratio and preventing proteolytic activities , 2004, Molecular Cancer.

[21]  F. Herpin,et al.  Molecular hydrogen beyond the optical edge of an isolated spiral galaxy , 2004, Nature.

[22]  R. Stupp,et al.  Plasma and Cerebrospinal Fluid Population Pharmacokinetics of Temozolomide in Malignant Glioma Patients , 2004, Clinical Cancer Research.

[23]  Karin Reed,et al.  Biochemical changes associated with a multidrug-resistant phenotype of a human glioma cell line with temozolomide-acquired resistance. , 2002, Biochemical pharmacology.

[24]  P. Cartron,et al.  The expression of a new variant of the pro-apoptotic molecule Bax, Baxpsi, is correlated with an increased survival of glioblastoma multiforme patients. , 2002, Human molecular genetics.

[25]  Thomas D. Schmittgen,et al.  Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. , 2001, Methods.

[26]  P. Narayan,et al.  Annexin V staining during reperfusion detects cardiomyocytes with unique properties. , 2001, American journal of physiology. Heart and circulatory physiology.

[27]  K. Vousden,et al.  Regulation and function of the p53 tumor suppressor protein. , 2001, Current opinion in cell biology.

[28]  M. Weller,et al.  Ezrin-Dependent Promotion of Glioma Cell Clonogenicity, Motility, and Invasion Mediated by BCL-2 and Transforming Growth Factor-β2 , 2001, The Journal of Neuroscience.

[29]  M. Berger,et al.  p53 effects both the duration of G2/M arrest and the fate of temozolomide-treated human glioblastoma cells. , 2001, Cancer research.

[30]  J. Kirkwood,et al.  Temozolomide, a novel alkylating agent with activity in the central nervous system, may improve the treatment of advanced metastatic melanoma. , 2000, The oncologist.

[31]  A. Asai,et al.  Expression level of Bcl-2 determines anti- or proapoptotic function. , 1999, Cancer research.

[32]  K. Irani,et al.  Bcl-2 regulates nonapoptotic signal transduction: inhibition of c-Jun N-terminal kinase (JNK) activation by IL-1 beta and hydrogen peroxide. , 1998, Molecular genetics and metabolism.

[33]  Sten Orrenius,et al.  Injected cytochrome c induces apoptosis , 1998, Nature.

[34]  R. Armstrong,et al.  Cell-specific Induction of Apoptosis by Microinjection of Cytochrome c , 1997, The Journal of Biological Chemistry.

[35]  G. Kroemer.  The proto-oncogene Bcl-2 and its role in regulating apoptosis , 1997, Nature Medicine.

[36]  J. Dichgans,et al.  Chemotherapy of human malignant glioma , 1997, Neurology.

[37]  D. Green,et al.  The Release of Cytochrome c from Mitochondria: A Primary Site for Bcl-2 Regulation of Apoptosis , 1997, Science.

[38]  W. Yung,et al.  Treatment of recurrent malignant gliomas with high-dose 13-cis-retinoic acid. , 1996, Clinical cancer research : an official journal of the American Association for Cancer Research.

[39]  John Calvin Reed.  Regulation of apoptosis by bcl-2 family proteins and its role in cancer and chemoresistance. , 1995, Current opinion in oncology.

[40]  Lei Shi,et al.  MiR-125 b is critical for the suppression of human U 251 glioma stem cell proliferation , 2010 .

[41]  D. Kardamakis,et al.  Increased Bax/Bcl-2 ratio up-regulates caspase-3 and increases apoptosis in the thymus of patients with myasthenia gravis. , 2007, In vivo.

[42]  J. Lieberman,et al.  Apoptotic proteins in the temporal cortex in schizophrenia: high Bax/Bcl-2 ratio without caspase-3 activation. , 2004, The American journal of psychiatry.