Cyclic AMP stimulation of transferrin secretion by breast cancer cell grown on extracellular matrix or in two-compartment culture chambers.
Extrahepatic synthesis and secretion of transferrin (Tf), the major iron-carrying protein, have been described in normal and tumoral tissues suggesting a potential role for paracrine or autocrine function. In breast tumor cell MCF-7, we have previously shown a Tf secretion stimulated by estradiol which might confer selective growth advantages of these rapidly proliferating cells. The present work refers to possible additional Tf functions related to differentiation of breast tumor cells. We induced MCF-7 cell differentiation by the cyclic AMP derivative, dibutyryl cAMP (dB cAMP) and studied Tf secretion in different culture conditions after labeling with [35S] methionine. Our results demonstrate that dB cAMP stimulates Tf secretion only in culture environment that permits access to the basolateral surface and caters to the polarity requirements of the cell. These results suggest that Tf may also act as a modulator of cellular differentiation in breast cancer cells.
Vandewalle
B
B
Laboratoire d'Endocrinologie Expérimentale, Centre Oscar Lambret, Lille, France.
Hornez
L
L
Révillion
F
F
Lefebvre
J
J
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology*; D001345:Autoradiography; D001943:Breast Neoplasms; D003994:Bucladesine / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000502:physiology*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D005109:Extracellular Matrix / Q000502:physiology*; D005260:Female; D006801:Humans; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D009077:Mucins / Q000096:biosynthesis; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D013462:Sulfur Radioisotopes; D014168:Transferrin / Q000096:biosynthesis* / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000494:pharmacology
D009077:Mucins; D011960:Receptors, Estrogen; D013462:Sulfur Radioisotopes; D014168:Transferrin; D014361:Trypsin Inhibitors; D004958:Estradiol; D003994:Bucladesine; D008715:Methionine; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine