Distinct functional differences of human progesterone receptors A and B on gene expression and growth regulation in two endometrial carcinoma cell lines

Abstract

To study the functional differences between the two progesterone receptor isoforms (hPRA and hPRB) in human endometrial cancer, two new endometrial carcinoma cell lines were created-one expressing hPRA and one expressing hPRB.A well-differentiated, hPR-negative Ishikawa cell line was stably transfected with either hPRA or hPRB cDNA. Transfected cells were selected, and two cell lines expressing approximately equal amounts of receptor were isolated-one expressing hPRA (PRA-14) and one expressing hPRB (PRB-59). Cell growth experiments revealed a growth-inhibitory response to progestins (MPA and R5020) in the PRB-59 cells but not in the PRA-14 cells. Differences in expression of genes targeted by the two isoforms were studied using a cDNA expression array technique. A different set of genes appeared to be progesterone regulated in the PRA-14 cells than in the PRB-59 cells. None of the genes were regulated by both hPRA and hPRB. Insulin-like growth factor binding protein 3 expression was studied in more detail as an example of a gene regulated in PRB-59 cells but not in PRA-14 cells. We established a new model to study functional differences between the two hPR isoforms in human endometrial carcinoma cells. This model revealed distinctive differences in target gene regulation between the two hPR isoforms. Moreover, antiproliferative actions of progesterone on human endometrial cancer cells could be observed only in the PRB-expressing cell line.

Large-scale gene expression studies of the endometrium: what have we learnt?

“…Microarrays have been used to investigate the molecular effects of progesterone, which is known to reduce the risk of developing endometrial cancer, and PRs are found in endometrial cancer cells (Dai et al 2002, Oehler et al 2002, Smid-Koopman et al 2003. After treatment of normal, non-transformed endometrial epithelial cells with oestradiol and the synthetic progestogen norethisterone acetate, Wnt-7a, part of the Wnt family of secreted signalling molecules, was shown to be upregulated (Oehler et al 2002).…”

“…Two studies have examined the functional difference between the two human progesterone receptor (hPR) isoforms in human endometrial cancer (Dai et al 2002, Smid-Koopman et al 2003. Endometrial cancer cell lines, stably transfected with either hPRA or hPRB, were treated with progestins and differential gene expression was analysed using nylon cDNA arrays.…”

“…The array data revealed distinctive differences in target gene regulation between the two hPR isoforms. Only cells expressing hPRB were growth responsive to progesterone and expression levels of five different genes, insulin-like growth factor-binding protein-3, fibronectin and replication protein A (Smid-Koopman et al 2003) and fibronectin, integrin a 3 b 1 (Dai et al 2002) were downregulated in hPRB-expressing cells. The results emphasised that the relative distribution of hPRA and hPRB in endometrial cancer cells may have great implications on the behaviour of human endometrial tumours.…”

Primate-specific Melanoma Antigen-A11 Regulates Isoform-specific Human Progesterone Receptor-B Transactivation

“…3A) (38). Progesterone increased endogenous FKBP5 mRNA in IKPRB and IKPRAB cells but had no effect in parental IKLV or IKPRA cells (Fig.…”

“…Human endometrial adenocarcinoma Ishikawa cells and parental IKLV3 express low levels of PR (37) (38). Ishikawa and human cervical cancer HeLa cells were maintained in minimal essential medium (Invitrogen) containing 10% fetal bovine serum (Gemini BioProducts), 2 mM L-glutamine (Cellgro), penicillin, and streptomycin (Sigma).…”