TY - JOUR
T1 - Possible involvement of the inactivation of the Rho-Rho-kinase pathway in oncogenic Ras-induced transformation
AU - Izawa, Ichiro
AU - Amano, Mutsuki
AU - Chihara, Kazuyasu
AU - Yamamoto, Takaharu
AU - Kaibuchi, Kozo
N1 - Funding Information:
We thank Drs Y Kaziro and H Itoh (Tokyo Institute of Technology, Yokohama, Japan), I Yahara (Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan), and H Shiku (Mie University School of Medicine, Mie, Japan) for kindly providing Rat1 RasVal A1 cells, anti-actin polyclonal antibody, and anti-Ras antibody, respectively. We are grateful to Drs S Kuroda and H Qadota for helpful discussions. This study was supported by grants-in-aid for scientific research and for cancer research from the Ministry of Education, Science, and Culture of Japan (1997), and by grants from Kirin Brewery Company Limited.
PY - 1998/12/3
Y1 - 1998/12/3
N2 - Recent evidence has strongly suggested the involvement of Rho family small guanosine triphosphatases (GTPases) in Ras-induced transformation. To further clarify the role of Rho family GTPases in Ras-induced transformation, we examined the effects of dominant active or dominant negative forms of Rho family GTPases on the morphological changes induced by oncogenic Ras (Ras(V12)) in Rat1 fibroblasts. The cells expressing Ras(V12) showed the severe disruption of actin stress fibers and cell adhesions. The coexpression of dominant active form of Rho (Rho(V14)) reverted not only the formation of stress fibers and focal adhesions but also cell-cell adhesions in Ras-transformed Rat1 cells. In addition, the coexpression of constitutively activated Rho-kinase, a downstream effector of Rho, restored the assembly of stress fibers and focal adhesions. Treatment of Rat1 cells with lysophosphatidic acid, which is known to activate the Rho-Rho-kinase pathway, enhanced the stress fiber formation, whereas it failed to induce the stress fiber formation in the cells expressing Ras(V12). These results suggest that the Rho-Rho-kinase pathway may be inactivated in the cells expressing Ras(V12), and this may contribute to oncogenic Ras-induced transformation.
AB - Recent evidence has strongly suggested the involvement of Rho family small guanosine triphosphatases (GTPases) in Ras-induced transformation. To further clarify the role of Rho family GTPases in Ras-induced transformation, we examined the effects of dominant active or dominant negative forms of Rho family GTPases on the morphological changes induced by oncogenic Ras (Ras(V12)) in Rat1 fibroblasts. The cells expressing Ras(V12) showed the severe disruption of actin stress fibers and cell adhesions. The coexpression of dominant active form of Rho (Rho(V14)) reverted not only the formation of stress fibers and focal adhesions but also cell-cell adhesions in Ras-transformed Rat1 cells. In addition, the coexpression of constitutively activated Rho-kinase, a downstream effector of Rho, restored the assembly of stress fibers and focal adhesions. Treatment of Rat1 cells with lysophosphatidic acid, which is known to activate the Rho-Rho-kinase pathway, enhanced the stress fiber formation, whereas it failed to induce the stress fiber formation in the cells expressing Ras(V12). These results suggest that the Rho-Rho-kinase pathway may be inactivated in the cells expressing Ras(V12), and this may contribute to oncogenic Ras-induced transformation.
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U2 - 10.1038/sj.onc.1202213
DO - 10.1038/sj.onc.1202213
M3 - Article
C2 - 9879992
AN - SCOPUS:0032481126
VL - 17
SP - 2863
EP - 2871
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 22
ER -