Autocrine growth stimulation by transforming growth factor-alpha in human non-small cell lung cancer.
We studied the biological response to and production of transforming growth factor-alpha (TGF-alpha) by the non-small cell lung carcinoma (NSCLC) clonal cell lines H226b, H322a, H460a, H596b. Each of these cell lines expressed epidermal growth factor receptor (EGFR) as determined by [125I]EGF competitive binding and Scatchard analysis and by phosphorylation. The receptors were functionally active as determined in immune complex kinase assays. H322a, H226b, H460a, and H596b cells showed stimulated [3H]thymidine (Thd) uptake in response to TGF-alpha. Exogenously added TGF-alpha increased colony formation in soft agar for three of the cell lines in media containing serum. All cell lines expressed TGF-alpha detected by immunohistochemistry and TGF-alpha mRNA, although to differing degrees. Cell lysates and spent media competed for EGFR binding with EGF, thus demonstrating production of TGF-alpha-like activity. The anti-TGF-alpha monoclonal antibody AB-3 inhibited the uptake of [3H]Thd by proliferating H322a and H226b cells but not H460a and H596b cells. No inhibition occurred with MOPC21 antibody and inhibition was completely reversed by addition of TGF-alpha to the culture. Suramin inhibited cell proliferation and [3H]Thd uptake by all cell lines. Inhibition of H460a and H596b cells was reversed with exogenous TGF-alpha but not PDGF. Our data suggests that TGF-alpha is a mediator of autocrine growth stimulation for NSCLC cells, and that for some NSCLC cells cytoplasmic binding of receptor and ligand is the primary mechanism for autocrine growth stimulation.
Putnam
E A
EA
Department of Thoracic Surgery, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Yen
N
N
Gallick
G E
GE
Steck
P A
PA
Fang
K
K
Akpakip
B
B
Gazdar
A F
AF
Roth
J A
JA
D000818:Animals; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D066246:ErbB Receptors / Q000032:analysis / Q000187:drug effects; D006801:Humans; D008175:Lung Neoplasms / Q000737:chemistry / Q000503:physiopathology*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D012334:RNA, Neoplasm / Q000032:analysis; D011869:Radioligand Assay / Q000379:methods; D011994:Recombinant Proteins / Q000187:drug effects / Q000494:pharmacology; D013498:Suramin / Q000494:pharmacology; D016211:Transforming Growth Factor alpha / Q000187:drug effects / Q000494:pharmacology / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000187:drug effects; D014410:Tumor Stem Cell Assay
D012334:RNA, Neoplasm; D011994:Recombinant Proteins; D016211:Transforming Growth Factor alpha; D013498:Suramin; D066246:ErbB Receptors