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Kido M, Idogaki H, Nishikawa K, Omasa T. Low-concentration staurosporine improves recombinant antibody productivity in Chinese hamster ovary cells without inducing cell death. J Biosci Bioeng 2020; 130:525-532. [PMID: 32800439 DOI: 10.1016/j.jbiosc.2020.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/23/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022]
Abstract
Chinese hamster ovary (CHO) cells are used as host cells for biopharmaceutical production, including monoclonal antibodies (mAbs). Arresting the cell cycle with chemical compounds is an effective approach to improve biopharmaceutical productivity. In a previous study, potential new cell cycle-arresting compounds were screened from marine-derived microorganism culture extracts, and it was suggested that staurosporine might improve mAb productivity in CHO cells via cell cycle arrest. The purpose of this study was to demonstrate the effectiveness of staurosporine as a cell-cycle arresting compound to improve mAb productivity. The optimal staurosporine concentration range was initially investigated using batch cultures. Thereafter, the effects on the culture profile and mAb productivity were evaluated using fed-batch cultures. Staurosporine at concentrations ≥10 nM induced cell death, but at concentrations ≤5 nM did not. In the range of 2-4 nM, cell growth was inhibited, whereas the specific production rate (Qp) and cell longevity were improved in a dose-dependent manner. The Qp and maximum mAb concentration with 4 nM staurosporine improved by 36.3 and 5.2%, respectively, compared to those with control conditions. Cell viability post-culture without staurosporine was 40.0 ± 0.3%, whereas with 4 nM staurosporine, it was 90.1 ± 1.0%. Flow cytometric analysis indicated cell-cycle arrest at the G1/G0 phase with 4 nM staurosporine addition. The present study highlighted the efficacy of staurosporine in improving mAb production by causing cell-cycle arrest. Further research into staurosporine analogs and how to use them will lead to development of more effective industrial production technologies of biopharmaceuticals.
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Affiliation(s)
- Masahide Kido
- Research and Development Division, OSAKA SODA Co., Ltd., Amagasaki, Hyogo 660-0842, Japan; Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Hideaki Idogaki
- Research and Development Division, OSAKA SODA Co., Ltd., Amagasaki, Hyogo 660-0842, Japan
| | - Kouji Nishikawa
- Research and Development Division, OSAKA SODA Co., Ltd., Amagasaki, Hyogo 660-0842, Japan
| | - Takeshi Omasa
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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2
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Diojan L, Zhaleh H, Azadbakht M, Bidmeshkipour A, Khodamoradi E. Effect of Pentoxifylline on Staurosporine-Induced Neurite Elongation in PC12 Cells. Asian Pac J Cancer Prev 2019; 20:2633-2638. [PMID: 31554357 PMCID: PMC6976854 DOI: 10.31557/apjcp.2019.20.9.2633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Indexed: 11/25/2022] Open
Abstract
Objective: Pentoxifylline enhances neurite elongation in PC12 cells. This study investigated the effects of pentoxifylline on staurosporine-induced neurite elongation in PC12 cells. Materials and Methods: There were five treatment groups, including treatment group I (1 nM), treatment group II (10 nM), treatment group III (100 nM), treatment group IV (1uM), and treatment group V (10 mM of pentoxifylline), together with 214 nM staurosporine for a range of time (6, 12 and 24 hours). Cells only treated with staurosporine at a concentration of 214 nM were used as the control group. Cell proliferation, cell death, immunocytochemistry assay, and Total Neurite Length were assessed. Results: The results showed that pentoxifylline increased cell viability (p<0.05) in a dose- and time-dependent manner, and cell death assay showed that cell death decreased in a dose- and time-dependent manner (p<0.05). TNL increased significantly compared with control cells (p<0.05). Immunocytochemistry assay showed that pentoxifylline at low and high concentrations enhanced β-tubulin III and GFAP protein expression compared with control cells. Conclusion: It can be concluded that pentoxifylline has positive effects on the staurosporine-induced neurite outgrowth process in PC12 cells.
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Affiliation(s)
- Loghman Diojan
- Department of Radiology and Nuclear Medicine, School of Allied Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Hossein Zhaleh
- Substance Abuse Prevention Research Center, Institute of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mehri Azadbakht
- Department of Biology, Faculty of Sciences, Razi University, Kermanshah, Iran
| | - Ali Bidmeshkipour
- Department of Biology, Faculty of Sciences, Razi University, Kermanshah, Iran
| | - Ehsan Khodamoradi
- Department of Radiology and Nuclear Medicine, School of Allied Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran.
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Goji T, Takahara K, Negishi M, Katoh H. Cystine uptake through the cystine/glutamate antiporter xCT triggers glioblastoma cell death under glucose deprivation. J Biol Chem 2017; 292:19721-19732. [PMID: 29038291 DOI: 10.1074/jbc.m117.814392] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/12/2017] [Indexed: 12/22/2022] Open
Abstract
Oncogenic signaling in cancer cells alters glucose uptake and utilization to supply sufficient energy and biosynthetic intermediates for survival and sustained proliferation. Oncogenic signaling also prevents oxidative stress and cell death caused by increased production of reactive oxygen species. However, elevated glucose metabolism in cancer cells, especially in glioblastoma, results in the cells becoming sensitive to glucose deprivation (i.e. in high glucose dependence), which rapidly induces cell death. However, the precise mechanism of this type of cell death remains unknown. Here, we report that glucose deprivation alone does not trigger glioblastoma cell death. We found that, for cell death to occur in glucose-deprived glioblastoma cells, cystine and glutamine also need to be present in culture media. We observed that cystine uptake through the cystine/glutamate antiporter xCT under glucose deprivation rapidly induces NADPH depletion, reactive oxygen species accumulation, and cell death. We conclude that although cystine uptake is crucial for production of antioxidant glutathione in cancer cells its transport through xCT also induces oxidative stress and cell death in glucose-deprived glioblastoma cells. Combining inhibitors targeting cancer-specific glucose metabolism with cystine and glutamine treatment may offer a therapeutic approach for glioblastoma tumors exhibiting high xCT expression.
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Affiliation(s)
- Takeo Goji
- From the Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan and
| | | | - Manabu Negishi
- From the Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan and.,Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hironori Katoh
- From the Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan and .,Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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Takayasu T, Hama S, Yamasaki F, Saito T, Watanabe Y, Nosaka R, Sugiyama K, Kurisu K. p16 Gene Transfer Induces Centrosome Amplification and Abnormal Nucleation Associated with Survivin Downregulation in Glioma Cells. Pathobiology 2015; 82:1-8. [PMID: 25765578 DOI: 10.1159/000368196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/07/2014] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE In human glioma cells, p16 gene transfer induced G1/S arrest, increased radiosensitivity and abnormal nucleation (especially bi- and multinucleation). Survivin suppression caused G2/M arrest, radiosensitization and an increase in aneuploidy accompanied by centrosome amplification. Abnormal nucleation and aneuploidy represent chromosome instability (CIN), and it is well known that centrosome amplification leads to CIN. However, little has been reported that suggests that transferring p16 causes centrosome overduplication during the G1/S phase. METHODS The p16 gene was transferred into p16-null human glioma cell lines (U251MG and D54MG) using adenovirus with or without irradiation. Centrosome amplification was evaluated by immunofluorescence. We also investigated the DNA replication licensing factor CDT1, its inhibitor geminin and survivin expression as regulators of chromosomal segregation. RESULTS p16 gene transfer with radiation initiated the greatest degree of centrosome overduplication. CDT1 showed low levels, geminin was unchanged and survivin decreased in Ax-hp16-infected cells with radiation. Those changes of factors affecting DNA licensing or chromosomal segregation might contribute to CIN. CONCLUSION p16 transfer caused centrosome amplification even in G1/S phase-arrested cells. This suggests that p16 is involved in abnormal nucleation and radiosensitization in human glioma cells. © 2015 S. Karger AG, Basel.
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Affiliation(s)
- Takeshi Takayasu
- Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Han DF, Zhang JX, Wei WJ, Tao T, Hu Q, Wang YY, Wang XF, Liu N, You YP. Fenofibrate induces G0/G1 phase arrest by modulating the PPARα/FoxO1/p27kip pathway in human glioblastoma cells. Tumour Biol 2015; 36:3823-9. [DOI: 10.1007/s13277-014-3024-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/26/2014] [Indexed: 12/01/2022] Open
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Guzmán C, Bagga M, Kaur A, Westermarck J, Abankwa D. ColonyArea: an ImageJ plugin to automatically quantify colony formation in clonogenic assays. PLoS One 2014; 9:e92444. [PMID: 24647355 PMCID: PMC3960247 DOI: 10.1371/journal.pone.0092444] [Citation(s) in RCA: 426] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/21/2014] [Indexed: 11/18/2022] Open
Abstract
The clonogenic or colony formation assay is a widely used method to study the number and size of cancer cell colonies that remain after irradiation or cytotoxic agent administration and serves as a measure for the anti-proliferative effect of these treatments. Alternatively, this assay is used to quantitate the transforming potential of cancer associated genes and chemical agents. Therefore, there is a need for a simplified and standardized analysis of colony formation assays for both routine laboratory use and for parallelized automated analysis. Here we describe the freely available ImageJ-plugin "ColonyArea", which is optimized for rapid and quantitative analysis of focus formation assays conducted in 6- to 24-well dishes. ColonyArea processes image data of multi-well dishes, by separating, concentrically cropping and background correcting well images individually, before colony formation is quantitated. Instead of counting the number of colonies, ColonyArea determines the percentage of area covered by crystal violet stained cell colonies, also taking the intensity of the staining and therefore cell density into account. We demonstrate that these parameters alone or in combination allow for robust quantification of IC50 values of the cytotoxic effect of two staurosporines, UCN-01 and staurosporine (STS) on human glioblastoma cells (T98G). The relation between the potencies of the two compounds compared very well with that obtained from an absorbance based method to quantify colony growth and to published data. The ColonyArea ImageJ plugin provides a simple and efficient analysis routine to quantitate assay data of one of the most commonly used cellular assays. The bundle is freely available for download as supporting information. We expect that ColonyArea will be of broad utility for cancer biologists, as well as clinical radiation scientists.
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Affiliation(s)
- Camilo Guzmán
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Manish Bagga
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Amanpreet Kaur
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
- Department of Pathology, University of Turku, Turku, Finland
- Turku Doctoral Program of Biomedical Sciences, University of Turku and Åbo Akademi University, Turku, Finland
| | - Jukka Westermarck
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
- Department of Pathology, University of Turku, Turku, Finland
| | - Daniel Abankwa
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
- * E-mail:
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Peng F, Li X, Jiang JX, Wang M, Tian R, Xu M, Guo XJ, Qin RY. Staurosporine inhibits cell proliferation and induces apoptosis in pancreatic cancer cell line Panc-1. Shijie Huaren Xiaohua Zazhi 2013; 21:2578-2584. [DOI: 10.11569/wcjd.v21.i25.2578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of staurosporine (ST) on cell proliferation and apoptosis in pancreatic cancer cell line Panc-1, and to explore the possible mechanisms involved.
METHODS: After Panc-1 cells were treated with different concentrations of ST for different durations, cell proliferation was assessed by CCK-8 method, cell apoptosis was detected by Hoechst 33258 staining and flow cytometry, cell cycle distribution was investigated by flow cytometry, and expression of cyclin A, cyclin D1, Cdk4 and P21 proteins was detected by Western blot.
RESULTS: ST significantly inhibited the proliferation of Panc-1 cells (P < 0.05) in a concentration- and time-dependent manner. Treatment with ST significantly induced apoptosis of Panc-1 cells, and the apoptosis rate of Panc-1 cells treated with ST increased significantly compared with control cells (P < 0.05). Treatment with ST induced cell cycle arrest in G1 phase (P < 0.05). Moreover, ST treatment significantly decreased the expression of cyclin D1 and Cdk4 proteins and increased the expression of P21 protein in Panc-1 cells (all P < 0.05). Low concentrations of ST raised the expression of cyclin A in Panc-1 cells, while high concentrations of ST reduced the expression of cyclin A (P < 0.05).
CONCLUSION: ST significantly inhibits proliferation and induces apoptosis of Panc-1 cells possibly by inducing cell cycle arrest in G1 phase.
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Murray MM, Bui T, Smith M, Bagheri-Yarmand R, Wingate H, Hunt KK, Keyomarsi K. Staurosporine is chemoprotective by inducing G1 arrest in a Chk1- and pRb-dependent manner. Carcinogenesis 2013; 34:2244-52. [PMID: 23722650 DOI: 10.1093/carcin/bgt186] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Chemotherapeutic agents have been the mainstay of cancer therapy for years. However, their effectiveness has been limited by toxicities they impart on normal cells. Staurosporine (ST) has been shown to arrest normal, but not breast cancer, cells in G1. Therefore, ST may become a chemoprotective agent, arresting normal cells while allowing tumor cells to enter cell cycle phases where they are sensitive to chemotherapeutic agents. Understanding the mechanism of ST-mediated G1 arrest may allow for a beneficial chemoprotective treatment strategy for patients. We utilized 76NE6 (pRb+/p53-), 76NF2V (pRb+/p53+) and 76NE7 (pRb-/P53+) non-tumorigenic human mammary epithelial cell lines to understand the role of the Rb and p53 pathways in ST-directed G1 arrest. CDK4 was downregulated by ST in Rb+ cells, but its presence could not reverse the arrest, neither did its stable downregulation alter ST-mediated cellular response. ST-mediated G1 arrest required pRb, which in turn initiated a cascade of events leading to inhibition of CDK4. Further assessment of this pathway revealed that Chk1 expression and activity were required for the Rb-dependent arrest. For example, pRb+ cells with small interfering RNA to Chk1 had approximately 60% less cells in G1 phase compared with controls and pRb- cells do not arrest upon ST. Furthermore, Chk1 expression facilitates the release of the Rb+ cells from G1 arrest. Collectively, our data suggest that pRb cooperates with Chk1 to mediate a G1 arrest only in pRb+ cells. The elucidation of this pathway can help identify novel agents to protect cancer patients against the debilitating effects of chemotherapy.
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Zhaleh H, Azadbakht M, Bidmeshki Pour A. Possible involvement of calcium channels and plasma membrane receptors on Staurosporine-induced neurite outgrowth. Bosn J Basic Med Sci 2012; 12:20-5. [PMID: 22364299 PMCID: PMC4362412 DOI: 10.17305/bjbms.2012.2526] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 10/31/2011] [Indexed: 12/24/2022] Open
Abstract
Staurosporine as a protein kinases inhibitor induced cell death or neurite outgrowth in PC12 cells. We investigated the involvement of calcium channel and plasma membrane receptors on staurosporine inducing neurite outgrowth in PC12 cells. PC12 cells were preincubated with NMDA receptor inhibitors (1.8 mM ketamine and 1µM MK801, treatment 1) or L-Type Calcium channels (100 μM nifedipine and 100 µM flavoxate hydrochloride, treatment 2) or calcium-calmoduline kinasses (10 μM trifluoprazine, treatment 3) and nifedipine, MK801, flavoxate hydrochloride and ketamine (treatment4) or without pretreatments (control). Then, the cells were cultured in RPMI culture medium containing 214nM staurosporine for induction of neurite outgrowth. The percentage of Cell cytotoxicity and apoptotic index was assessed. Total neurite length (TNL) and fraction of cell differentiation were assessed. After 24h, the percentage of cell cytotoxicity were increased in treatments 1, 2 and 4 compared with control (p<0.05). After 6h, apoptotic index was similar between all treatments. After 12h, apoptotic index were increased in treatment 4 compared with control (p<0.05). After 24h, apoptotic index were increased in treatments 1, 2 and 4 compared with control (p<0.05). TNL were decreased in treatments 1, 2 and 4 compared with control in different times of assessment (6, 12 and 24 h) (p<0.05). The fraction of cell differentiation were decreased in treatments 1, 2 and 4 compared with control (p<0.05). It can be concluded that the possible involvement of L-type calcium channel and the N-methyl D-aspartate receptor on staurosporine-induced neurite outgrowth process in PC12 cells.
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Affiliation(s)
- Hossein Zhaleh
- Department of Biology, Razi University, Taqe Bostan, Baghe Abrisham, Kermanshah, Iran.
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10
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Yamasaki D, Kawabe N, Nakamura H, Tachibana K, Ishimoto K, Tanaka T, Aburatani H, Sakai J, Hamakubo T, Kodama T, Doi T. Fenofibrate suppresses growth of the human hepatocellular carcinoma cell via PPARα-independent mechanisms. Eur J Cell Biol 2011; 90:657-64. [PMID: 21514001 DOI: 10.1016/j.ejcb.2011.02.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/22/2010] [Accepted: 02/15/2011] [Indexed: 12/15/2022] Open
Abstract
Fenofibrate, a peroxisome proliferator-activated receptor (PPAR) α agonist, is a hypolipidemic drug. Although several studies have explored the fenofibrate-induced antiproliferative effect in cultured human cells, it is not clear which role PPARα plays in this antiproliferative effect. Therefore, we investigated the antiproliferative mechanism of fenofibrate in Huh7 (human hepatoma cell line). Cell viability was measured by the WST-8 assay and cell proliferation was assessed using the BrdU incorporation assay. The cell cycle was analyzed by flow cytometry. The cyclins, tumor suppressor proteins and regulators of the AKT signaling pathway were analyzed by immunoblotting. Using flow cytometry, we showed that fenofibrate blocks entry into the S phase of the cell cycle. We certified that this G1 arrest is caused by the reduction of cyclin A and E2F1 and the accumulation of the cyclin-dependent kinase inhibitor p27. Interestingly, the antiproliferative effect of fenofibrate was not affected by the PPARα antagonist (GW6471) or by PPARα-specific siRNA. These results suggest that fenofibrate suppresses Huh7 cell growth through a PPARα independent mechanism. Furthermore, we showed that treatment of Huh7 cells with fenofibrate leads to suppression of AKT phosphorylation. We also found for the first time that fenofibrate increased the C-terminal modulator protein (CTMP), which inhibits AKT phosphorylation. Our data suggest that fenofibrate inhibits the proliferation of Huh7 cells by blocking Akt activation, and that CTMP is one of the key players for this antiproliferative property of fenofibrate in Huh7 cells.
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Affiliation(s)
- Daisuke Yamasaki
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
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Stegh AH, Brennan C, Mahoney JA, Forloney KL, Jenq HT, Luciano JP, Protopopov A, Chin L, Depinho RA. Glioma oncoprotein Bcl2L12 inhibits the p53 tumor suppressor. Genes Dev 2010; 24:2194-204. [PMID: 20837658 DOI: 10.1101/gad.1924710] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Glioblastoma multiforme (GBM) is a lethal brain tumor characterized by intense apoptosis resistance and extensive necrosis. Bcl2L12 (for Bcl2-like 12) is a cytoplasmic and nuclear protein that is overexpressed in primary GBM and functions to inhibit post-mitochondrial apoptosis signaling. Here, we show that nuclear Bcl2L12 physically and functionally interacts with the p53 tumor suppressor, as evidenced by the capacity of Bcl2L12 to (1) enable bypass of replicative senescence without concomitant loss of p53 or p19 (Arf), (2) inhibit p53-dependent DNA damage-induced apoptosis, (3) impede the capacity of p53 to bind some of its target gene promoters, and (4) attenuate endogenous p53-directed transcriptomic changes following genotoxic stress. Correspondingly, The Cancer Genome Atlas profile and tissue protein analyses of human GBM specimens show significantly lower Bcl2L12 expression in the setting of genetic p53 pathway inactivation. Thus, Bcl2L12 is a multifunctional protein that contributes to intense therapeutic resistance of GBM through its ability to operate on two key nodes of cytoplasmic and nuclear signaling cascades.
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Affiliation(s)
- Alexander H Stegh
- Belfer Institute for Applied Cancer Science, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
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12
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Staurosporine increases toxicity of gemcitabine in non-small cell lung cancer cells: role of protein kinase C, deoxycytidine kinase and ribonucleotide reductase. Anticancer Drugs 2010; 21:591-9. [PMID: 20436341 DOI: 10.1097/cad.0b013e32833a3543] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Gemcitabine, a deoxycytidine analog, active against non-small cell lung cancer, is phosphorylated by deoxycytidine kinase (dCK) to active nucleotides. Earlier, we found increased sensitivity to gemcitabine in P-glycoprotein (SW-2R160) and multidrug resistance-associated protein (SW-2R120), overexpressing variants of the human SW1573 non-small cell lung cancer cells. This was related to increased dCK activity. As protein kinase C (PKC) is higher in 2R120 and 2R160 cells and may control the dCK activity, we investigated whether gemcitabine sensitivity was affected by the protein kinase C inhibitor, staurosporine, which also modulates the cell cycle. Ten nmol/l staurosporine enhanced the sensitivity of SW1573, 2R120 and 2R160 cells 10-fold, 50-fold and 270-fold, respectively. Staurosporine increased dCK activity about two-fold and the activity of thymidine kinase 2, which may also activate gemcitabine. Staurosporine also directly increased dCK in cell free extracts. Staurosporine decreased expression of the free transcription factor E2F and of ribonucleotide reductase (RNR), a target for gemcitabine inhibition. In conclusion, staurosporine may potentiate gemcitabine by increasing dCK and decreasing E2F and RNR, which will lead to a more pronounced RNR inhibition.
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Di Bernardo G, Squillaro T, Dell’Aversana C, Miceli M, Cipollaro M, Cascino A, Altucci L, Galderisi U. Histone Deacetylase Inhibitors Promote Apoptosis and Senescence in Human Mesenchymal Stem Cells. Stem Cells Dev 2009; 18:573-81. [DOI: 10.1089/scd.2008.0172] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Giovanni Di Bernardo
- Department of Experimental Medicine, Section of Biotechnology and Molecular Biology, Excellence Research Center for Cardiovascular Diseases, Second University of Naples, Naples, Italy
| | | | - Carmela Dell’Aversana
- Department of Experimental Medicine, Section of Biotechnology and Molecular Biology, Excellence Research Center for Cardiovascular Diseases, Second University of Naples, Naples, Italy
- Department of Pathology, Second University of Naples, Naples, Italy
| | - Marco Miceli
- Department of Pathology, Second University of Naples, Naples, Italy
| | - Marilena Cipollaro
- Department of Experimental Medicine, Section of Biotechnology and Molecular Biology, Excellence Research Center for Cardiovascular Diseases, Second University of Naples, Naples, Italy
| | - Antonino Cascino
- Department of Experimental Medicine, Section of Biotechnology and Molecular Biology, Excellence Research Center for Cardiovascular Diseases, Second University of Naples, Naples, Italy
| | - Lucia Altucci
- Department of Pathology, Second University of Naples, Naples, Italy
| | - Umberto Galderisi
- Department of Experimental Medicine, Section of Biotechnology and Molecular Biology, Excellence Research Center for Cardiovascular Diseases, Second University of Naples, Naples, Italy
- Barro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, Temple University, Philadelphia, Pennsylvania
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Rieger J, Lemke D, Maurer G, Weiler M, Frank B, Tabatabai G, Weller M, Wick W. Enzastaurin-induced apoptosis in glioma cells is caspase-dependent and inhibited by BCL-XL. J Neurochem 2008; 106:2436-48. [PMID: 18662322 DOI: 10.1111/j.1471-4159.2008.05586.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The novel protein kinase C-beta inhibitor enzastaurin (ENZA) induced apoptosis in LNT-229 and T98G cells whereas A172 cells were resistant. Further, ENZA reduced proliferation in glioblastoma-initiating cells T 269 and T 323 but did not induce apoptosis. ENZA-induced apoptosis involved cleavage of caspases 3, 8, and 9 and led to mitochondrial cytochrome c release and was strongly suppressed by the broad spectrum caspase inhibitor zVAD-fmk but only slightly by the expression of the viral caspase 1/8 inhibitor cytokine response modifier-A. ENZA did not reduce the phosphorylation of protein kinase B (Akt), but of p70 S6 kinase and of its substrate S6 protein in T98G cells. Inhibition of the phosphatidylinositol 3 kinase signaling pathway did not restore sensitivity of A172 cells towards ENZA, and constitutively active Akt did not protect LNT-229 and T98G cells from ENZA-induced apoptosis. Dephosphorylation of glycogen synthase kinase 3beta, a biomarker of ENZA action, and cell death induction by ENZA were separately regulated. Inhibition or activation of Akt only weakly modulated ENZA-induced dephosphorylation of glycogen synthase kinase 3beta. In ENZA-resistant A172 cells, apoptosis ligand 2 (Apo2L.0)-induced cleavage of caspases 3, 8, and 9 was increased by ENZA, resulting in synergistic activity of ENZA and Apo2L.0.
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Affiliation(s)
- Johannes Rieger
- Laboratory of Molecular Neuro-Oncology, Department of General Neurology, University of Tübingen, Tübingen, Germany
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Yamasaki F, Johansen MJ, Zhang D, Krishnamurthy S, Felix E, Bartholomeusz C, Aguilar RJ, Kurisu K, Mills GB, Hortobagyi GN, Ueno NT. Acquired resistance to erlotinib in A-431 epidermoid cancer cells requires down-regulation of MMAC1/PTEN and up-regulation of phosphorylated Akt. Cancer Res 2007; 67:5779-88. [PMID: 17575145 DOI: 10.1158/0008-5472.can-06-3020] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Erlotinib (Tarceva), an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has clinical activity in advanced lung cancer, but disease that initially responds to erlotinib eventually progresses. The mechanism of this acquired resistance is unclear. We established two erlotinib-resistant pools of A-431 cells, a well-characterized epidermoid cancer cell line that constitutively overexpresses EGFR and is sensitive to erlotinib, by continuous exposure to erlotinib over a 6-month period. The extent of EGFR gene amplification or mutation of the EGFR tyrosine kinase domain was not altered in the resistant cells. Intracellular erlotinib concentrations, determined by liquid chromatography-tandem mass spectrometry, were almost the same in all three cell lines. Immunoprecipitation with EGFR antibody followed by detection with phosphotyrosine antibody revealed that erlotinib effectively reduced EGFR phosphorylation in both parental cells and resistant cells. Erlotinib induced mutated in multiple advanced cancers 1/phosphatase and tensin homologue (MMAC1/PTEN) and suppressed phosphorylated Akt (Ser(473)) but not in the erlotinib-resistant cells. Overexpression of MMAC1/PTEN by transfection with Ad.MMAC1/PTEN or by pharmacologic suppression of Akt activity restored erlotinib sensitivity in both resistant pools. Further, transfection of parental A-431 cells with constitutively active Akt was sufficient to cause resistance to erlotinib. We propose that acquired erlotinib resistance associated with MMAC1/PTEN down-regulation and Akt activation could be overcome by inhibitors of signaling through the phosphatidylinositol 3-kinase pathway.
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Affiliation(s)
- Fumiyuki Yamasaki
- Breast Cancer Translational Research Laboratory, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009, USA
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16
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Yamasaki F, Kajiwara Y, Hama S, Murakami T, Hidaka T, Saito T, Yoshioka H, Sugiyama K, Arita K, Kurisu K. Retinoblastoma protein prevents staurosporine-induced cell death in a retinoblastoma-defective human glioma cell line. Pathobiology 2007; 74:22-31. [PMID: 17496430 DOI: 10.1159/000101048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Accepted: 12/29/2006] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE To investigate the mechanism of staurosporine-induced glioma cell death and cell cycle arrest using adenovirus-mediated gene transfection, as well as the function of retinoblastoma (Rb) and genetic instability induced by staurosporine. METHODS Cell cycle regulation, cell death and nuclear abnormalities induced by staurosporine were examined using an adenovirus vector expressing Rb, p16 or p21 genes in human glioma cell lines. RESULTS The Rb-defective SF-539 cell line was resistant to staurosporine compared with cell lines expressing intact Rb. SF-539 glioma cells exposed to staurosporine became multinucleated and then died. Multinucleation was prevented in SF-539 cells transfected with the Rb gene, thus decreasing the death rate of these cells. CONCLUSIONS These results imply that enforced Rb expression protects cells from genomic instability induced by staurosporine regardless of its upstream molecular effects.
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Affiliation(s)
- Fumiyuki Yamasaki
- Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
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17
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McNeill-Blue C, Wetmore BA, Sanchez JF, Freed WJ, Merrick BA. Apoptosis mediated by p53 in rat neural AF5 cells following treatment with hydrogen peroxide and staurosporine. Brain Res 2006; 1112:1-15. [PMID: 16901471 DOI: 10.1016/j.brainres.2006.07.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 06/26/2006] [Accepted: 07/04/2006] [Indexed: 12/14/2022]
Abstract
AF5 neural cells derived from fetal rat mesencephalic tissue were immortalized with a truncated SV40 LT vector lacking the p53-inactivating domain to maintain long-term cultures with a p53-responsive phenotype. This study examined p53 function in producing programmed cell death in propagating AF5 neural cells after exposure to hydrogen peroxide (H2O2) and the kinase inhibitor staurosporine (STSP). Concentration-dependent exposure of AF5 cells to 0-800 mM H2O2 and STSP at 0-1000 nM revealed increasing cytotoxicity from MTS cell viability assays. Apoptosis occurred at 400 mM H2O2 as evidenced by subG1 DNA and Annexin V flow cytometry analyses and cellular immunofluorescence staining with propidium iodide, anti-Annexin V and DAPI. DNA fragmentation, caspase-3/7 activity and cytochrome c release into cytosol also confirmed H2O2-mediated apoptotic events. p53 protein levels were increased over 24 h by H2O2 in a coordinated fashion with mdm2 expression. p53 activation by H2O2 was evidenced by elevated Ser15 phosphorylation, increased luciferase p53 reporter activity and upregulation of the downstream p53 targets p21(waf1) and apoptotic proteins, bax, Noxa and PUMA. STSP exposure produced apoptosis demonstrated by DNA fragmentation, caspase-3/7 activity, cytochrome c release and over 24 h was accompanied by sustained increase in p53 and Ser15 phosphorylation, rise in p21(waf1) and bax and a transient increase in p53 reporter activity but without Annexin V binding. These findings demonstrate that AF5 cells undergo apoptosis in response to H2O2-mediated oxidative stress and signal pathway disruption by STSP that therefore would be useful in studies related to p53-dependent neuronal cell death and neurodegeneration.
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Affiliation(s)
- Charlesene McNeill-Blue
- Proteomics Group, National Center for Toxicogenomics, National Institute of Environmental Health Sciences, National Institute of Health, Department of Health and Human Services, D2-04, P.O. Box 12233, Research Triangle Park, NC 27709, USA
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18
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Harmalkar MN, Shirsat NV. Staurosporine-induced growth inhibition of glioma cells is accompanied by altered expression of cyclins, CDKs and CDK inhibitors. Neurochem Res 2006; 31:685-92. [PMID: 16770740 DOI: 10.1007/s11064-006-9068-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
Staurosporine was found to bring about complete growth inhibition of human glioma cell lines. U87 MG cells were arrested in S phase while U373 MG cells in G2/M phase on staurosporine treatment. Consistent with this observation, no change in G1 phase regulators viz., Cyclin D1, D3 and CDK4 was seen on staurosporine treatment. The levels of CDK2, CDC2, Cyclin A and Cyclin B proteins decreased, while the levels of CDK inhibitors viz., p21 and p27 were found to increase on staurosporine treatment. The mRNA levels of CDK2 and CDC2 genes were also found to decrease on staurosporine treatment. Thus apart from staurosporine's known direct inhibitory effect on CDK2 and CDC2 activities, staurosporine was found to down-regulate activities of these two kinases by modulating the expression of the kinases themselves as well that of their activating partners (Cyclins) and their inhibitors.
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Affiliation(s)
- Mugdha N Harmalkar
- Neurooncology, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410208, India
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19
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Chen GG, Sin FLF, Leung BCS, Ng HK, Poon WS. Differential role of hydrogen peroxide and staurosporine in induction of cell death in glioblastoma cells lacking DNA-dependent protein kinase. Apoptosis 2005; 10:185-92. [PMID: 15711934 DOI: 10.1007/s10495-005-6073-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Various DNA double-strand break repair mechanisms, in which DNA-dependent protein kinase (DNA-PK) has a major role, are involved both in the development and treatment of glioblastoma. The aim of the present study was to investigate how glioblastoma cells responded to hydrogen peroxide and staurosporine (STS) and how such a response is related to DNA-PK. Two human glioblastoma cell lines, M059J cells that lack DNA-PK activity, and M059K cells that express a normal level of DNA-PK, were exposed to hydrogen peroxide or STS. The response of the cells to hydrogen peroxide or STS was recorded by measuring cell death, which was detected by three different methods-MTT, annexin-V and propidium iodide staining, and JC-1 mitochondrial probe. The result showed that both hydrogen peroxide and STS were able to induce cell death of the glioblastoma cells and that the former was mainly associated with necrosis and the latter with apoptosis. Glioblastoma cells lacking DNA-PK were less sensitive to STS treatment than those containing DNA-PK. However, DNA-PK had no significant influence on hydrogen peroxide treatment. We further found that catalase, an antioxidant enzyme, could prevent cell death induced by hydrogen peroxide but not by STS, suggesting that the pathways leading to cell death by hydrogen peroxide and STS are different. We conclude that hydrogen peroxide and STS have differential effects on cell death of glioblastoma cells lacking DNA-dependent protein kinase. Such differential roles in the induction of glioblastoma cell death can be of significant value in selecting and/or optimizing the treatment for this malignant brain tumor.
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Affiliation(s)
- G G Chen
- Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong.
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20
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Kawai H, Suzuki T, Kobayashi T, Mizuguchi H, Hayakawa T, Kawanishi T. Simultaneous imaging of initiator/effector caspase activity and mitochondrial membrane potential during cell death in living HeLa cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1693:101-10. [PMID: 15313012 DOI: 10.1016/j.bbamcr.2004.05.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Revised: 05/19/2004] [Accepted: 05/28/2004] [Indexed: 11/19/2022]
Abstract
A family of cystein proteases, the caspases, plays a central role in mediating cell death. In this study, we measured the activation of the initiator and effector caspase in real time, and studied the relationship between caspase activity and mitochondrial membrane potential in living cells by means of bioimaging. We also designed and developed a fluorescence resonance energy transfer (FRET)-based genetically encoded fluorescent indicator, which consisted of yellow fluorescent protein (YFP), a peptide sequence which can be cleaved by specific caspases, and cyan fluorescent protein (CFP). Two peptide sequences which could be cleaved by initiator caspases and effector caspases, respectively, were used. Simultaneous real-time measurements of the caspase activity and mitochondrial membrane potential in the cells treated with TNF-alpha and staurosporine revealed that dying cells showed caspase activation and mitochondrial depolarization, and that these events, however, were not firmly linked. Although it takes anywhere from 1 to over 10 h after the addition of the cell death inducer for the caspases to begin to be activated, initiator caspases and effector caspases are activated within a short period of time at the last stage in the entire process leading to cell death.
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Affiliation(s)
- Hiroshi Kawai
- Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan. kawai.nihs.go.jp
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21
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Dawson G, Moskal JR, Dawson SA. Transfection of 2,6 and 2,3‐sialyltransferase genes and GlcNAc‐transferase genes into human glioma cell line U‐373 MG affects glycoconjugate expression and enhances cell death. J Neurochem 2004; 89:1436-44. [PMID: 15189346 DOI: 10.1111/j.1471-4159.2004.02435.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human glioma cell line U-373 MG expresses CMP-NeuAc : Galbeta1,3GlcNAc alpha2,3-sialyltransferase [EC No. 2.4.99.6] (alpha2,3ST), UDP-GlcNAc : beta-d-mannoside beta1,6-N-acetylglucosaminyltransferase V [EC 2.4.1.155] (GnT-V) and UDP-GlcNAc3: beta-d-mannoside beta1,4-N-acetylglucosaminyltransferase III [EC 2.4.1.144] (GnT-III) but not CMP-NeuAc : Galbeta1,4GlcNAc alpha2,6-sialyltransferase [EC 2.4.99.1] (alpha2,6ST) under normal culture conditions. We have previously shown that transfection of the alpha2,6ST gene into U-373 cells replaced alpha2,3-linked sialic acids with alpha2,6 sialic acids, resulting in a marked inhibition of glioma cell invasivity and a significant reduction in adhesivity. We now show that U-373 cells, which are typically highly resistant to cell death induced by chemotherapeutic agents (< 10% death in 18 h), become more sensitive to apoptosis following overexpression of these four glycoprotein glycosyltransferases. U-373 cell viability showed a three-fold decrease (from 20 to 60% cell death) following treatment with staurosporine, C2-ceramide or etoposide, when either alpha2,6ST and GnT-V genes were stably overexpressed. Even glycosyltransferases typically raised in cancer cells, such as alpha2,3ST and GnT-III, were able to decrease viability two-fold (from 20 to 40% cell death) following stable overexpression. The increased susceptibility of glycosyltransferase-transfected U-373 cells to pro-apoptotic drugs was associated with increased ceramide levels in Rafts, increased caspase-3 activity and increased DNA fragmentation. In contrast, the same glycosyltransferase overexpression protected U-373 cells against a different class of apoptotic drugs, namely the phosphatidylinositol 3-kinase inhibitor LY294002. Thus altered surface protein glycosylation of a human glioblastoma cell line can lead to lowered resistance to chemotherapeutic agents.
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Affiliation(s)
- G Dawson
- Department of Pediatrics MC 4068, University of Chicago School of Medicine, 5841 S. Maryland Avenue, Chicago, IL 60637, USA.
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22
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Kruman II, Wersto RP, Cardozo-Pelaez F, Smilenov L, Chan SL, Chrest FJ, Emokpae R, Gorospe M, Mattson MP. Cell cycle activation linked to neuronal cell death initiated by DNA damage. Neuron 2004; 41:549-61. [PMID: 14980204 DOI: 10.1016/s0896-6273(04)00017-0] [Citation(s) in RCA: 272] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2003] [Revised: 09/08/2003] [Accepted: 12/19/2003] [Indexed: 10/26/2022]
Abstract
Increasing evidence indicates that neurodegeneration involves the activation of the cell cycle machinery in postmitotic neurons. However, the purpose of these cell cycle-associated events in neuronal apoptosis remains unknown. Here we tested the hypothesis that cell cycle activation is a critical component of the DNA damage response in postmitotic neurons. Different genotoxic compounds (etoposide, methotrexate, and homocysteine) induced apoptosis accompanied by cell cycle reentry of terminally differentiated cortical neurons. In contrast, apoptosis initiated by stimuli that do not target DNA (staurosporine and colchicine) did not initiate cell cycle activation. Suppression of the function of ataxia telangiectasia mutated (ATM), a proximal component of DNA damage-induced cell cycle checkpoint pathways, attenuated both apoptosis and cell cycle reentry triggered by DNA damage but did not change the fate of neurons exposed to staurosporine and colchicine. Our data suggest that cell cycle activation is a critical element of the DNA damage response of postmitotic neurons leading to apoptosis.
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Affiliation(s)
- Inna I Kruman
- Research Resources Branch, Intramural Research Program, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
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23
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Hama S, Matsuura S, Tauchi H, Yamasaki F, Kajiwara Y, Arita K, Yoshioka H, Heike Y, Mandai K, Kurisu K. p16 Gene transfer increases cell killing with abnormal nucleation after ionising radiation in glioma cells. Br J Cancer 2003; 89:1802-11. [PMID: 14583787 PMCID: PMC2394396 DOI: 10.1038/sj.bjc.6601299] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
It is well established that cells synchronised at the G1–S phase are highly radiosensitive. In this study, p16-null human glioma cell lines were induced into G1 cell cycle arrest by adenovirus-mediated p16 gene transfer, and examined for radiation-induced cell killing. Clonogenic analysis and trypan blue extraction test showed that the p16 gene transfer enhanced radiation-induced cell killing in p16-null glioma cell lines. TUNEL assays and pulse-field gel electrophoresis confirmed that the radiation-induced cell killing of p16-transfected cells could be caused by a nonapoptotic mechanism. Gimsa staining demonstrated that irradiation alone or Ax-mock infection plus irradiation results in a slight increase in the frequency of cells with abnormal nucleus, compared to unirradiated uninfected or Ax-mock infected cells. However, Ax-hp16 or Ax-hp21 infection alone modestly increased the frequency of cells with abnormal nucleus (especially bi- and multinucleation), and 4-Gy irradiation of Ax-hp16 or Ax-hp21 infected cells substantially enhanced this frequency. These results suggest that there exists some unknown interaction between radiation and p16 in cytoplasm/membranes, which decreases cytokinesis and promotes abnormal nucleation. Thus, p16 expression prevented radiation-induced apoptosis by promoting abnormal nucleation, thereby leading to another mode of cell death.
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Affiliation(s)
- S Hama
- Department of Neurosurgery, Hiroshima University School of Medicine, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
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