Pit-1 is expressed in normal and tumorous human breast and regulates GH secretion and cell proliferation
C Gil-Puig, S Seoane, M Blanco… - European journal of …, 2005 - academic.oup.com
C Gil-Puig, S Seoane, M Blanco, M Macia, T Garcia-Caballero, C Segura…
European journal of endocrinology, 2005•academic.oup.comBackground The transcription factor pituitary-1 (Pit-1) is mainly expressed in the pituitary
gland, where it has critical roles in cell differentiation and as a transcriptional factor for GH
and prolactin (PRL). It is also expressed in human extrapituitary tissues (placenta, lymphoid
and haematopoietic tissues) and cell lines (human breast adenocarcinoma cells, MCF-7).
Despite the widely suggested roles of GH and PRL in the progression of proliferative
mammary disorders, Pit-1 expression in human mammary gland has not yet been reported …
gland, where it has critical roles in cell differentiation and as a transcriptional factor for GH
and prolactin (PRL). It is also expressed in human extrapituitary tissues (placenta, lymphoid
and haematopoietic tissues) and cell lines (human breast adenocarcinoma cells, MCF-7).
Despite the widely suggested roles of GH and PRL in the progression of proliferative
mammary disorders, Pit-1 expression in human mammary gland has not yet been reported …
Background
The transcription factor pituitary-1 (Pit-1) is mainly expressed in the pituitary gland, where it has critical roles in cell differentiation and as a transcriptional factor for GH and prolactin (PRL). It is also expressed in human extrapituitary tissues (placenta, lymphoid and haematopoietic tissues) and cell lines (human breast adenocarcinoma cells, MCF-7). Despite the widely suggested roles of GH and PRL in the progression of proliferative mammary disorders, Pit-1 expression in human mammary gland has not yet been reported.
Objective
To evaluate the expression of Pit-1 in human breast and, using the MCF-7 cell line, to investigate whether Pit-1 overexpression regulates GH expression and increases cell proliferation.
Methods
Using real-time RT-PCR, western blotting and immunohistochemistry, we evaluated the expression of Pit-1 mRNA and protein in seven normal human breasts and 14 invasive ductal mammary carcinomas. GH regulation by Pit-1 in MCF-7 cells was evaluated using RT-PCR, western blotting, ELISA and transfection assays. Cell proliferation was evaluated using bromodeoxyuridine.
Results
We found expression of Pit-1 mRNA and protein in both normal and tumorous human breast. We also found that Pit-1 mRNA levels were significantly increased in breast carcinoma compared with normal breast. In MCF-7 cells, Pit-1 overexpression increased GH mRNA and protein concentrations and significantly increased cell proliferation.
Conclusions
These findings indicate that Pit-1 is expressed in human breast, that it regulates endogenous human mammary GH secretion, and that it increases cell proliferation. This suggests that, depending on its level of expression, Pit-1 may be involved in normal mammary development, breast disorders, or both.
Oxford University Press