TY - JOUR
T1 - Radiation-stimulated ERK1/2 and JNK1/2 signaling can promote cell cycle progression in human colon cancer cells
AU - Carón, Rubén W.
AU - Yacoub, Adly
AU - Mitchell, Clint
AU - Zhu, Xiaoyu
AU - Hong, Young
AU - Sasazuki, Takehiko
AU - Shirasawa, Senji
AU - Hagan, Michael P.
AU - Grant, Steven
AU - Dent, Paul
N1 - Funding Information:
MAPK mitogen activated protein kinase PI3K phosphatidylinositol 3-kinase Ionizing radiation is used as a primary treatment for many types of carcinoma. While ERK extracellular regulated kinase it has been appreciated for many years that radiation causes cell death, it has only recently JNK c-JunNH2-terminalkinase become accepted that radiation has some potential to enhance proliferation in the surviving hMDM2 human form of the murine double fraction of cells.1,2We and others have discovered that exposure of carcinoma cells to low minute protein radiation doses causes an initial early activation of growth factor receptors in the plasma membrane, followed by secondary receptor activation that is dependent upon autocrine growth factors.3,4 Receptor activation enhances the activities of RAS family molecules that This work was funded; to P.D. from PHS grant signal to cause activation of multiple intracellular signal transduction pathways. Secondary (R01-CA88906, P01-CA72955, R01-DK52825), activation of intracellular signal transduction pathways by growth factors and radiation has Department of Defense Awards (BC980148, been correlated to altered expression of cell cycle regulatory proteins and may, under certain (P01-CA72955; R01-CA63753; R01-CA77141)BC020338); to S.G. from PHS grants circumstances, promote cell proliferation.5,6 ©2005 LANDES BIOSCIENCEGrowth factors interact with plasma membrane receptors, which transduce signals A portion of Dr. Yacoub’s funding is from theand a Leukemia Society of America grant 6405-97. through the membrane to its inner leaflet.7-14 Growth factor signals, via guanine Department of Radiation Oncology, Virginia nucleotide exchange factors, can increase the amount of GTP bound to membrane-asso-Commonwealth University. The Massey Cancer ciated GTP binding proteins, including RAS.15,10There are 3 widely recognized isoforms Center Flow cytometry core laboratory was sup- of RAS: Harvey (H), Kirsten (K) and Neuroblastoma (N).16 GTP-RAS can interact with ported in part by NIH grant P30 CA16059. multiple downstream effector molecules including the Raf-1 protein kinase and the P.D. would like to thank Dr. E. Bernhard phosphatidyl inositol 3-kinase (PI3K) lipid kinase. Receptor-stimulated guanine during the initiation of these studies.(University of Pennsylvania) for useful discussions nucleotide exchange of ‘RAS’ to the GTP-bound form permits Raf-1 and P110 PI3K to
PY - 2005/3
Y1 - 2005/3
N2 - The abilities of mutated active K-RAS and H-RAS proteins, in an isogenic human carcinoma cell system, to modulate the activity of signaling pathways and cell cycle progression following exposure to ionizing radiation is largely unknown. Loss of K-RAS D13 expression in parental HCT116 colorectal carcinoma cells blunted basal ERK1/2, AKT and JNK1/2 activity by ∼70%. P38 activity was not detected. Deletion of the allele to express activated K-RAS nearly abolished radiation-induced activation of all signaling pathways. Expression of H-RAS V12 in HCT116 cells lacking an activated RAS molecule (H-RAS V12 cells) restored basal ERK1/2 and AKT activity to that observed in parental cells, but did not restore or alter basal JNK1/2 and p38 activity. In parental cells radiation (1 Gy) caused stronger ERK1/2 pathway activation compared to that of the PI3K/AKT pathway. In H-RAS V12 cells radiation caused stronger PI3K/AKT pathway activation compared to that of the ERK1/2 pathway. Radiation (1 Gy) promoted S phase entry in parental HCT116 cells within 24h, but not in either HCT116 cells lacking K-RAS D13 expression or in H-RAS V12 cells. In parental cells radiation-stimulated S phase entry correlated with ERK1/2-, JNK1/2- and PI3K-dependent increased expression of cyclin D1 and cyclin A, and to a lesser extent cyclin E, 6-24 h after exposure. Cyclin A and cyclin D1 expression were not increased by radiation in cells lacking K-RAS D13 expression or in H-RAS V12 cells. Radiation (1 Gy) modestly enhanced expression of p53, hMDM2 and p21 in parental cells 2-6h after exposure, which was abolished in cells lacking K-RAS D13 expression. Introduction of H-RAS V12 into cells lacking mutant active RAS partially restored radiation-induced expression of p21 and p53, and enhanced the induction of hMDM2 beyond that observed in parental cells. Collectively, our findings argue that the coordinated activation of multiple signaling pathways, in particular ERK1/2 and JNK1/2, by radiation is required to elevate the expression of G1 and S phase cyclin proteins and to promote S phase entry in human colon carcinoma cells expressing wild type p53. In HCT116 cells H-RAS V12 promotes hMDM2 expression after radiation exposure which correlates with reduced p53 expression and increased cell survival.
AB - The abilities of mutated active K-RAS and H-RAS proteins, in an isogenic human carcinoma cell system, to modulate the activity of signaling pathways and cell cycle progression following exposure to ionizing radiation is largely unknown. Loss of K-RAS D13 expression in parental HCT116 colorectal carcinoma cells blunted basal ERK1/2, AKT and JNK1/2 activity by ∼70%. P38 activity was not detected. Deletion of the allele to express activated K-RAS nearly abolished radiation-induced activation of all signaling pathways. Expression of H-RAS V12 in HCT116 cells lacking an activated RAS molecule (H-RAS V12 cells) restored basal ERK1/2 and AKT activity to that observed in parental cells, but did not restore or alter basal JNK1/2 and p38 activity. In parental cells radiation (1 Gy) caused stronger ERK1/2 pathway activation compared to that of the PI3K/AKT pathway. In H-RAS V12 cells radiation caused stronger PI3K/AKT pathway activation compared to that of the ERK1/2 pathway. Radiation (1 Gy) promoted S phase entry in parental HCT116 cells within 24h, but not in either HCT116 cells lacking K-RAS D13 expression or in H-RAS V12 cells. In parental cells radiation-stimulated S phase entry correlated with ERK1/2-, JNK1/2- and PI3K-dependent increased expression of cyclin D1 and cyclin A, and to a lesser extent cyclin E, 6-24 h after exposure. Cyclin A and cyclin D1 expression were not increased by radiation in cells lacking K-RAS D13 expression or in H-RAS V12 cells. Radiation (1 Gy) modestly enhanced expression of p53, hMDM2 and p21 in parental cells 2-6h after exposure, which was abolished in cells lacking K-RAS D13 expression. Introduction of H-RAS V12 into cells lacking mutant active RAS partially restored radiation-induced expression of p21 and p53, and enhanced the induction of hMDM2 beyond that observed in parental cells. Collectively, our findings argue that the coordinated activation of multiple signaling pathways, in particular ERK1/2 and JNK1/2, by radiation is required to elevate the expression of G1 and S phase cyclin proteins and to promote S phase entry in human colon carcinoma cells expressing wild type p53. In HCT116 cells H-RAS V12 promotes hMDM2 expression after radiation exposure which correlates with reduced p53 expression and increased cell survival.
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UR - http://www.scopus.com/inward/citedby.url?scp=25444480542&partnerID=8YFLogxK
U2 - 10.4161/cc.4.3.1249
DO - 10.4161/cc.4.3.1249
M3 - Article
C2 - 15655348
AN - SCOPUS:25444480542
SN - 1538-4101
VL - 4
SP - 456
EP - 464
JO - Cell Cycle
JF - Cell Cycle
IS - 3
ER -
