Abstract
Radiosensitivity of various normal tissues is largely dependent on radiation-triggered signal transduction pathways. Radiation simultaneously initiates distinct signaling from both DNA damage and cell membrane. Specifically, DNA strand breaks initiate cell-cycle delay, strand-break repair or programmed cell death, whereas membrane-derived signaling through phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) enhances cell viability. Here, activation of cytosolic phospholipase A2 (cPLA2) and production of the lipid second-messenger lysophosphatidylcholine were identified as initial events (within 2 min) required for radiation-induced activation of Akt and ERK1/2 in vascular endothelial cells. Inhibition of cPLA2 significantly enhanced radiation-induced cytotoxicity due to an increased number of multinucleated giant cells and cell cycle-independent accumulation of cyclin B1 within 24–48 h of irradiation. Delayed programmed cell death was detected at 72–96 h after treatment. Endothelial functions were also affected by inhibition of cPLA2 during irradiation resulting in attenuated cell migration and tubule formation. The role of cPLA2 in the regulation of radiation-induced activation of Akt and ERK1/2 and cell viability was confirmed using human umbilical vein endothelial cells transfected with shRNA for cPLA2α and cultured embryonic fibroblasts from cPLA2α−/− mice. In summary, an immediate radiation-induced cPLA2-dependent signaling was identified that regulates cell viability and, therefore, represents one of the key regulators of radioresistance of vascular endothelial cells.
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Abbreviations
- PLA2:
-
phospholipase A2
- PI3K:
-
phosphatidylinositol 3-kinase
- MAPK:
-
mitogen-activated protein kinase
- ERK:
-
extracellular signal-regulated kinase
- AA:
-
arachidonic acid
- LPC:
-
lysophosphatidylcholine
- HUVECs:
-
human umbilical vein endothelial cells
- MEFs:
-
mouse embryonic fibroblasts
- PBS:
-
phosphate-buffered saline
- TLC:
-
thin-layer chromatography
- PI:
-
propidium iodide
- DAPI:
-
4′,6-diamidino-2-phenylindole
References
Kolesnick R, Fuks Z . Radiation and ceramide-induced apoptosis. Oncogene 2003; 22: 5897–5906.
Haimovitz-Friedman A, Kan CC, Ehleiter D, Persaud RS, McLoughlin M, Fuks Z et al. Ionizing radiation acts on cellular membranes to generate ceramide and initiate apoptosis. J Exp Med 1994; 180: 525–535.
Geng L, Tan J, Himmelfarb E, Schueneman A, Niermann K, Brousal J et al. A specific antagonist of the p110delta catalytic component of phosphatidylinositol 3′-kinase, IC486068, enhances radiation-induced tumor vascular destruction. Cancer Res 2004; 64: 4893–4899.
Edwards E, Geng L, Tan J, Onishko H, Donnelly E, Hallahan DE. Phosphatidylinositol 3-kinase/Akt signaling in the response of vascular endothelium to ionizing radiation. Cancer Res 2002; 62: 4671–4677.
Tan J, Hallahan DE . Growth factor-independent activation of protein kinase B contributes to the inherent resistance of vascular endothelium to radiation-induced apoptotic response. Cancer Res 2003; 63: 7663–7667.
Tan J, Geng L, Yazlovitskaya EM, Hallahan DE . Protein kinase B/Akt-dependent phosphorylation of glycogen synthase kinase-3beta in irradiated vascular endothelium. Cancer Res 2006; 66: 2320–2327.
Valerie K, Yacoub A, Hagan MP, Curiel DT, Fisher PB, Grant S et al. Radiation-induced cell signaling: inside-out and outside-in. Mol Cancer Ther 2007; 6: 789–801.
Mikkelsen RB, Wardman P . Biological chemistry of reactive oxygen and nitrogen and radiation-induced signal transduction mechanisms. Oncogene 2003; 22: 5734–5754.
Maclachlan T, Narayanan B, Gerlach VL, Smithson G, Gerwien RW, Folkerts O et al. Human fibroblast growth factor 20 (FGF-20; CG53135-05): a novel cytoprotectant with radioprotective potential. Int J Radiat Biol 2005; 81: 567–579.
Cabral GA . Lipids as bioeffectors in the immune system. Life Sci 2005; 77: 1699–1710.
Farooqui AA, Horrocks LA . Phospholipase A2-generated lipid mediators in the brain: the good, the bad, and the ugly. Neuroscientist 2006; 12: 245–260.
Chakraborti S . Phospholipase A(2) isoforms: a perspective. Cell Signal 2003; 15: 637–665.
Bonventre JV . The 85-kD cytosolic phospholipase A2 knockout mouse: a new tool for physiology and cell biology. J Am Soc Nephrol 1999; 10: 404–412.
Prokazova NV, Zvezdina ND, Korotaeva AA . Effect of lysophosphatidylcholine on transmembrane signal transduction. Biochemistry (Mosc) 1998; 63: 31–37.
Fujita Y, Yoshizumi M, Izawa Y, Ali N, Ohnishi H, Kanematsu Y et al. Transactivation of fetal liver kinase-1/kinase-insert domain-containing receptor by lysophosphatidylcholine induces vascular endothelial cell proliferation. Endocrinology 2006; 147: 1377–1385.
Murugesan G, Sandhya Rani MR, Gerber CE, Mukhopadhyay C, Ransohoff RM, Chisolm GM et al. Lysophosphatidylcholine regulates human microvascular endothelial cell expression of chemokines. J Mol Cell Cardiol 2003; 35: 1375–1384.
Sugiyama S, Kugiyama K, Ogata N, Doi H, Ota Y, Ohgushi M et al. Biphasic regulation of transcription factor nuclear factor-kappaB activity in human endothelial cells by lysophosphatidylcholine through protein kinase C-mediated pathway. Arterioscler Thromb Vasc Biol 1998; 18: 568–576.
Dent P, Yacoub A, Fisher PB, Hagan MP, Grant S . MAPK pathways in radiation responses. Oncogene 2003; 22: 5885–5896.
Dent P, Yacoub A, Contessa J, Caron R, Amorino G, Valerie K et al. Stress and radiation-induced activation of multiple intracellular signaling pathways. Radiat Res 2003; 159: 283–300.
Hwang A, Muschel RJ . Radiation and the G2 phase of the cell cycle. Radiat Res 1998; 150: S52–S59.
Kramer A, Lukas J, Bartek J . Checking out the centrosome. Cell Cycle 2004; 3: 1390–1393.
Castedo M, Perfettini JL, Roumier T, Kroemer G . Cyclin-dependent kinase-1: linking apoptosis to cell cycle and mitotic catastrophe. Cell Death Differ 2002; 9: 1287–1293.
Castedo M, Perfettini JL, Roumier T, Andreau K, Medema R, Kroemer G . Cell death by mitotic catastrophe: a molecular definition. Oncogene 2004; 23: 2825–2837.
Ianzini F, Bertoldo A, Kosmacek EA, Phillips SL, Mackey MA . Lack of p53 function promotes radiation-induced mitotic catastrophe in mouse embryonic fibroblast cells. Cancer Cell Int 2006; 6: 11.
Valko M, Leibfritz D, Moncol J, Cronin MT, Mazur M, Telser J . Free radicals and antioxidants in normal physiological functions and human disease. Int J Biochem Cell Biol 2007; 39: 44–84.
Rodel F, Keilholz L, Herrmann M, Sauer R, Hildebrandt G . Radiobiological mechanisms in inflammatory diseases of low-dose radiation therapy. Int J Radiat Biol 2007; 83: 357–366.
Pelevina II, Gotlib V, Konradov AA . 20 years after Chernobyl accident – is it a lot or not for the estimation its characteristics? Radiats Biol Radioecol 2006; 46: 240–247.
Geng L, Donnelly E, McMahon G, Lin PC, Sierra-Rivera E, Oshinka H et al. Inhibition of vascular endothelial growth factor receptor signaling leads to reversal of tumor resistance to radiotherapy. Cancer Res 2001; 61: 2413–2419.
Kufe D, Weichselbaum R . Radiation therapy: activation for gene transcription and the development of genetic radiotherapy-therapeutic strategies in oncology. Cancer Biol Ther 2003; 2: 326–329.
Truman JP, Gueven N, Lavin M, Leibel S, Kolesnick R, Fuks Z et al. Down-regulation of ATM protein sensitizes human prostate cancer cells to radiation-induced apoptosis. J Biol Chem 2005; 280: 23262–23272.
Hirabayashi T, Murayama T, Shimizu T . Regulatory mechanism and physiological role of cytosolic phospholipase A2. Biol Pharm Bull 2004; 27: 1168–1173.
Tsutsumi H, Kumagai T, Naitoo S, Ebina K, Yokota K . Synthetic peptide (P-21) derived from Asp-hemolysin inhibits the induction of apoptosis on HUVECs by lysophosphatidylcholine. Biol Pharm Bull 2006; 29: 907–910.
Cuneo KC, Geng L, Tan J, Brousal J, Shinohara ET, Osusky K et al. SRC family kinase inhibitor SU6656 enhances antiangiogenic effect of irradiation. Int J Radiat Oncol Biol Phys 2006; 64: 1197–1203.
Abdollahi A, Lipson KE, Han X, Krempien R, Trinh T, Weber KJ et al. SU5416 and SU6668 attenuate the angiogenic effects of radiation-induced tumor cell growth factor production and amplify the direct anti-endothelial action of radiation in vitro. Cancer Res 2003; 63: 3755–3763.
Zaher TE, Miller EJ, Morrow DM, Javdan M, Mantell LL . Hyperoxia-induced signal transduction pathways in pulmonary epithelial cells. Free Radic Biol Med 2007; 42: 897–908.
Ricci MS, Zong WX . Chemotherapeutic approaches for targeting cell death pathways. Oncologist 2006; 11: 342–357.
Upton AC . Carcinogenic effects of low-level ionizing radiation. J Natl Cancer Inst 1990; 82: 448–449.
Pierce DA, Shimizu Y, Preston DL, Vaeth M, Mabuchi K . Studies of the mortality of atomic bomb survivors. Report 12, Part I. Cancer: 1950–1990. Radiat Res 1996; 146: 1–27.
Herbert SP, Ponnambalam S, Walker JH . Cytosolic phospholipase A2-alpha mediates endothelial cell proliferation and is inactivated by association with the Golgi apparatus. Mol Biol Cell 2005; 16: 3800–3809.
Bligh EG, Dyer WJ . A rapid method of total lipid extraction and purification. Can J Biochem Physiol 1959; 37: 911–917.
Acknowledgements
We appreciate gift of mouse embryonic fibroblasts MEFcPLA2α−/− and MEFcPLA2α+/+ from Dr. JV Bonventre (Harvard Medical School, Boston, MA, USA). This work was supported in part by NIH grants R01-CA112385, R01-CA88076, R01-CA89674, R01-CA89888, and P50-CA90949, Elsa U. Pardee Foundation, Ingram Charitable Fund and Vanderbilt-Ingram Cancer Center, CCSG P30-CA68485.
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Yazlovitskaya, E., Linkous, A., Thotala, D. et al. Cytosolic phospholipase A2 regulates viability of irradiated vascular endothelium. Cell Death Differ 15, 1641–1653 (2008). https://doi.org/10.1038/cdd.2008.93
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DOI: https://doi.org/10.1038/cdd.2008.93
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