Transforming growth factor-alpha and insulin-like growth factor-I, but not epidermal growth factor, elicit autocrine stimulation of mitogenesis in endometrial cancer cell lines.
OBJECTIVE
Endometrial carcinoma cell lines were evaluated for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and insulin-like growth factor I (IGF-1) production and for autocrine stimulation.


METHODS
Conditioned, serum-free media (CM) from cell lines RL95-2, KLE, HEC, and Ishikawa (ISH) were concentrated radioimmunoassayed (RIA). Samples for the IGF-1 assay were extracted with acid-ethanol to remove IGF-1 binding protein. Polymerase chain reaction (PCR) was used to validate the presence of mRNA for growth factors and receptors. Cells were incubated with Ab528, an antibody blocking EGF receptors, and alphaIR3, an antibody blocking IGF-1 receptors. Proliferation was quantified using [3H]thymidine incorporation.


RESULTS
TGF-alpha was detected in CM: RL95-2 (0.4 +/- 0.001 ng/ml), KLE (0.7 +/- 0.003 ng/ml), HEC (0.8 +/- 0.01 ng/ml), ISH (1.2 +/- 0.05 ng/ml). No EGF was detected in CM. In extracted samples, IGF-1 was detected in CM: RL95-2 (0.8 +/- 0. 03 ng/ml), KLE (1.25 +/- 0.02 ng/ml), HEC (1.6 +/- 0.01 ng/ml), ISH (1.6 +/- 0.08 ng/ml). Unconditioned media served as the control. EGF, TGF-alpha, and IGF-1 mRNA was identified in all cell lines, as was the mRNA for EGF and IGF-1 receptors. Incubation with Ab528 or alphaIR3 resulted in significant inhibition of DNA synthesis in HEC 1A, KLE, and ISH. No inhibition was detected in the RL95-2 cell line. A control antibody did not inhibit the cell lines.


CONCLUSIONS
Autocrine production and stimulation of endometrial carcinoma cell lines by TGF-alpha and IGF-1 are demonstrated in three of four endometrial cancer cell lines. No measurable EGF was produced by any of the cell lines.
Reynolds
R K
RK
Division of Gynecologic Oncology, University of Michigan Hospitals, Ann Arbor, Michigan, 48109-0276, USA.
Hu
C
C
Baker
V V
VV
D019898:Autocrine Communication / Q000502:physiology*; D002455:Cell Division; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D004273:DNA, Neoplasm / Q000378:metabolism; D016889:Endometrial Neoplasms / Q000378:metabolism* / Q000473:pathology*; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D004273:DNA, Neoplasm; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I