A novel gene overexpressed in the prostate of castrated rats: hormonal regulation, relationship to apoptosis and to acquired prostatic cell androgen independence.
; Hennuy, Benoît ; Cornet, Anne et al
in Endocrinology (1999), 140(10), 4789-99
We have identified a novel complementary DNA (cDNA) corresponding to a gene overexpressed in the rat ventral prostate after castration. This cDNA displays 89.4% identity with 453 bp of a mouse EST and 81 ... [more ▼]
We have identified a novel complementary DNA (cDNA) corresponding to a gene overexpressed in the rat ventral prostate after castration. This cDNA displays 89.4% identity with 453 bp of a mouse EST and 81.5% identity with 157 bp of a human EST and was named PARM-1 for prostatic androgen-repressed message-1. The complete cDNA is 1187 bp long and codes for a protein of 298 amino acids that contains four potential glycosylation sites and three half cystinyl residues. The PARM-1 gene was found to be expressed at quite low levels in most rat tissues including those of the urogenital tract. The kinetic of induction of PARM-1 gene in the prostate was highly correlated to the development of apoptosis in the whole organ. Supplementation of castrated animals with androgens reversed both the process of apoptosis and the overexpression of PARM-1 gene. Supplementation with estrogens did not result in an increase in the PARM-1 messenger RNA levels when compared with the castration alone. However, the treatment resulted in a more rapid return to intact levels in the castrated plus estrogen group. When apoptosis of testis and prostate was induced in vivo by hypophysectomy, it was found that PARM-1 was only overexpressed in the prostate. Therefore, PARM-1 seems to be regulated by androgens only in the prostate. Using in situ hybridization and immunohistological techniques, we have shown that PARM-1 gene product is found exclusively in the epithelial cells of involuting prostate. Analysis by flow cytometry of MAT LyLu epithelial cells transiently expressing PARM-1 protein did not allow us to demonstrate a direct effect of PARM-1 gene overexpression on the programmed death of the transfected cells. Treatment of MAT LyLu cells by transforming growth factor-beta induced apoptosis but had no effect on PARM-1 production. However PARM-1 protein has been detected by Western blotting in various cell lines such as MAT LyLu, MAT Lu, and PIF, which are androgen independent. This would suggest that PARM-1 gene product would be a marker for acquired androgen-independence of these tumor cells. [less ▲]Detailed reference viewed: 20 (1 ULg)
Luteinizing hormone increases the abundance of various transcripts, independently of the androgens, in the rat prostate.
; Poncin, Joseph ; Hennuy, Benoît et al
in Biochemical and Biophysical Research Communications (1997), 233(1), 108-12
Differential display analysis was carried out to find, in the rat prostate, genes that could be regulated by Luteinizing Hormone (LH), independently of the androgens. Hypophysectomized and castrated adult ... [more ▼]
Differential display analysis was carried out to find, in the rat prostate, genes that could be regulated by Luteinizing Hormone (LH), independently of the androgens. Hypophysectomized and castrated adult rats were treated with either LH, testosterone or saline. Regulated discrete bands have been eluted and reamplified. After Northern blotting, the levels of mRNA corresponding to 8 PCR fragments were significantly increased by LH treatment. None of these inserts were found to be induced by testosterone. One insert was subcloned, sequenced and identified as the ribosomial protein S 23. A competitive RT-PCR assay was carried out on the full length S 23 cDNA and confirmed that its mRNA levels were stimulated by LH but not by testosterone. These results strongly suggest that the LH membrane receptor, previously shown to be expressed in the rat prostate, has a physiological significance in this organ. Moreover, it appears that the effect of LH on the rat prostate are independent of the androgens. [less ▲]Detailed reference viewed: 22 (4 ULg)