Ma. Steller et al., OVEREXPRESSION OF THE INSULIN-LIKE GROWTH-FACTOR-I RECEPTOR AND AUTOCRINE STIMULATION IN HUMAN CERVICAL-CANCER CELLS, Cancer research, 56(8), 1996, pp. 1761-1765
We characterized mechanisms of growth control involving insulin-like g
rowth factor-1 (IGF-I), IGF-2, and IGF-I receptor (IGF-IR) by investig
ating their expression in human cervical cancer cell lines, primary ce
rvical tumor cell cultures, and normal ectocervical epithelial cells m
aintained in short-term culture, By reverse transcription followed by
PCR, IGF-1 mRNA was not detected in any of the cell lines, whereas IGF
-2-mRNA transcripts were detected in all of them, Using the RNase prot
ection assay, low levels of IGF-2 mRNA were also detected in all of th
e cervical cancer cell lines, primary cervical tumor cell cultures, an
d normal ectocervical cultures tested, but no IGF-1 transcripts were d
etected, Scatchard analysis revealed 3- and 5-fold increases in IGF-1R
expression by the primary cervical cancer cell cultures and cervical
cancer cell lines, respectively, compared with the normal ectocervical
cells, In proliferation assays, epidermal growth factor (EGF) consist
ently enhanced cervical cancer cell growth, but an antisense oligonucl
eotide to IGF-2 uniformly inhibited the EGF-induced mitogenic effect,
These studies suggest that autocrine production of IGF-2 and overexpre
ssion of the IGF-1R are important components controlling the prolifera
tion of cervical carcinoma cells, and that autocrine IGF-2 production
in cervical cancer cells may participate in the mitogenic signaling of
EGF.