Malignant transformation of mouse BALB/3T3 cells by polyoma middle T antigen requires epidermal growth factor receptor expression.
The mouse cell line MO-5, which is defective in receptor-binding activity of epidermal growth factor (EGF), is very poorly transformed by polyoma middle T antigen or v-src gene, but activated c-H-ras and v-mos gene can induce the transformation (M. Ono, M. Yakushinji, K. Segawa, and M. Kuwano, Mol. Cell. Biol., 8: 4190-4196, 1988). We established clones of MO-5 expressing a functional EGF receptor (EGF-R) after introduction of the human EGF-R complementary DNA into MO-5 (MNER23 and MNER31), and we also established a clone (BNER4) expressing human EGF-R from the parental cell line, BALB/3T3. MNER23, MNER31, and BNER4 expressed EGF-R activity at about 2- to 6-fold higher levels than did control BALB/3T3 cells. A marked increase in DNA synthesis in response to EGF was observed in these BNER4, MNER23, and MNER31 cell lines compared to BALB/3T3 cells; however, there was little if any increase in DNA synthesis of MO-5 in the presence of EGF. Introduction of the polyoma middle T antigen gene into BALB/3T3, BNER4, MNER23, and MNER31 resulted in the appearance of transformation foci, but MO-5 again showed little response. We purified clones B4-mT-2, M23-mT-1, M23-mT-2, M23-mT-3, and M31-mT-13 from transformation foci of BNER4, MNER23, and MNER31 cells, which were respectively transfected with the middle T antigen. All of the middle T antigen-positive transfectants demonstrated abilities to form both colonies in soft agar and tumors in nude mice. The presence of EGF-R appears to be indispensable for malignant transformation by polyoma middle T antigen.
Ono
M
M
Department of Biochemistry, Oita Medical School, Japan.
Kuwano
M
M
Kung
H F
HF
D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000502:physiology*; D001665:Binding Sites; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D003001:Cloning, Molecular; D066246:ErbB Receptors / Q000502:physiology*; D005786:Gene Expression Regulation; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000209:etiology; D011233:Precipitin Tests; D014410:Tumor Stem Cell Assay
D000952:Antigens, Polyomavirus Transforming; D066246:ErbB Receptors