1. SIRPα1 and SIRPα2: Their role as tumor suppressors in breast carcinoma cells
- Author
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Yuji Nimura, Satoko Ito, Kazuo Hara, Masato Nagino, Tatsuyoshi Yamamoto, Michinari Hamaguchi, Toshio Kokuryo, Takeshi Senga, Koji Oda, Nobuyuki Tsunoda, Yukiko Yamasaki, and Reiji Kannagi
- Subjects
medicine.medical_specialty ,Stress fiber ,Molecular Sequence Data ,Biophysics ,Biology ,Biochemistry ,law.invention ,law ,Cell Line, Tumor ,Stress Fibers ,Internal medicine ,medicine ,Humans ,Amino Acid Sequence ,Breast ,Receptors, Immunologic ,skin and connective tissue diseases ,Molecular Biology ,Actin ,Cell Proliferation ,Oncogene ,Kinase ,Cell growth ,Tumor Suppressor Proteins ,Carcinoma ,Cell Biology ,Antigens, Differentiation ,Endocrinology ,Cancer research ,Suppressor ,Anchorage-Independent Growth ,Breast carcinoma - Abstract
We have previously reported that expression of SIRPalpha1/SHPS-1 was strongly suppressed in v-Src-transformed cells and its forced expression resulted in the suppression of anchorage-independent growth of the cells [K. Machida, S. Matsuda, K. Yamaki, T. Senga, A.A. Thant, H. Kurata, K. Miyazaki, K. Hayashi, T. Okuda, T. Kitamura, T. Hayakawa, M. Hamaguchi, v-Src suppresses SHPS-1 expression via the Ras-MAP kinase pathway to promote the oncogenic growth of cells, Oncogene 19 (2000) 1710-1718]. We examined the effect of human SIRPalpha1 expression in breast cancer cell lines, Hs578T and MCF7, and compared with the effect of SIRPalpha2 expression in Hs578T. Forced expression of either SIRPalpha1 or SIRPalpha2 did not perturb the growth of Hs578T in a conventional attached condition. Their expression, however, enforced the actin stress fiber formation and induced activation of Rho, but not Rac, in Hs578T cells. Moreover, forced expression of either SIRPalpha1 or SIRPalpha2 displayed distinct suppressive effect on the anchorage-independent growth of Hs578T cells. Similarly, forced expression of SIRPalpha1 in MCF7 specifically suppressed the anchorage-independent growth of the cells. Taken together, our results strongly suggest the function of SIRPalpha1 and 2 as type II tumor suppressors for human breast carcinoma.
- Published
- 2007