Cc. Hwang et al., INSULIN-LIKE GROWTH-FACTOR-I IS AN AUTOCRINE REGULATOR FOR THE BRAIN METASTATIC VARIANT OF A HUMAN NONSMALL CELL LUNG-CELL LINE, Cancer letters, 94(2), 1995, pp. 157-163
Insulin-like growth factor (IGF-I) is associated with autocrine and pa
racrine stimulation for cell growth and development of brain tumor cel
ls. The function of IGF-I in the brain metastatic variant of human lun
g cancer cells is investigated. The cells used here were derived in vi
vo with intracarotid injection of human non-small cell lung carcinoma
NCI-H226. The tumor was developed as a cultured cell line, H226Br, Unl
ike the parental cells, H226Br was tumorigenic in nu/nu nude mice. Rev
erse transcriptase-polymerase chain reaction showed that IGF-I transcr
ipt of H226Br is increased compared to that of parental cells. The amo
unt of IGF-I secreted in cultured medium of H226Br is higher than that
of cultured parental cells. The IGF-I receptor-specific antibody, alp
ha IR3, inhibits H226Br growth in serum-flee culture. The results esta
blished that IGF-I is an autocrine growth regulator for human non-smal
l cell lung cancer cells that progressed to brain.