Effects of testosterone and 17β-estradiol on angiotensin-induced changes in tyrosine kinase activity in the androgen-independent human prostate cancer cell line, DU145

Abstract

Angiotensin II (AngII), the main peptide of the renin‑angiotensin system (RAS), is involved in the proliferation of different types of cells, normal and pathological as well. The protein tyrosine kinases (PTKs) play an important role in the growth, differentiation and apoptosis of cells. AngII action depends on the hormonal milieu of the cell, and on sex steroid influence. Angiotensin 1‑7 (Ang1‑7), metabolite of AngII, shows opposite action to AngII in cells. The present study aimed to examine the influence of 17β‑estradiol and testosterone on AngII and Ang1‑7 action on PTK activity in androgen‑independent humane prostate cancer cell line DU145. Cell cultures of human prostate cancer DU145 cells were used as a source of PTKs. Cultures were exposed to different concentrations of AngII (5x10‑11 to 5x10‑9 M). The incubation with hormones lasted 15 min to limit the genomic effects of steroids. In the phosphorylation reaction, we used γ32P‑ATP as a donor of phosphate and a synthetic peptide, Poly(Glu, Tyr) (4:1), as a substrate. The specific activities of PTKs were defined as pmol of 32P incorporated into 1 mg of exogenous Poly(Glu, Tyr) per minute (pmol/mg/min). Our findings suggest that testosterone and 17β‑estradiol may change the effects of angiotensins in a rapid non‑genomic way, probably via membrane‑located receptors. The most significant change was caused by testosterone, whose effect was most significant on changes caused by Ang1‑7. AngII‑induced changes in phosphorylation appeared to be insensitive to the presence of testosterone, but were modified by 17β‑estradiol.

Interaction of Cytochrome C Oxidase with Steroid Hormones

“…At the same time, our data may be relevant to the experimental studies of steroid hormones action in vivo, studies with whole animals or (and particularly so) with cell cultures. Concentration of the hormones employed in such studies often reach a submillimolar or even millimolar range [ 29 , 30 , 31 , 32 , 33 ]. For example, in the paper of D’Ascenzo et al [ 29 ], the following IC 50% values are cited for inhibition of cell growth by anabolic steroides: testosterone, 100 µM; androstenedione, 375 µM; nandrolone, 9 µM; norandrostenedione, 500 µM; norandrostenediol, 6 mM.…”

Angiotensin 1–7 modulates molecular and cellular processes central to the pathogenesis of prostate cancer

“…No down-regulation in AT1 expression was observed in any prostate cancer line whereas a significant increase in expression was seen in the PC3 line. An earlier study presented that Ang1–7 can increase the protein level of the AT1 receptor in androgen-independent prostate cancer cells, and that this effect was attenuated by 17β-estradiol, not by testosterone 23 . Although the current study also evaluated the effect of Ang1–7 on the AT4 / IRAP receptor, its mRNA level was found to remain unchanged.…”

“…Interestingly, while 17-β-estradiol partially reverses this effect, testosterone both disrupts the action of Ang1–7 and leads to an increase in PTK activity. Moreover, the application of PD19234, a specific AT2 receptor antagonist, resulted in the reversal of the changes triggered by testosterone 23 .…”

Angiotensin II and Angiotensin Receptors 1 and 2—Multifunctional System in Cells Biology, What Do We Know?

“…Ang IV acted, at least partially, through AT2R, because addition of its blocker, PD123319, decreased inhibitory effect [83]. Domińska et al observed that steroid hormones, testosterone, and 17β-estradiol were capable of reversion of the action of Ang II and Ang 1-7, which decreased protein TK activity in the late-stage prostate cancer cell line-DU145 [84]. Ito et al noticed that inhibition of AT2R by its agonist, Compound 21 (C21), resulted in reduction of proliferation of prostate cancer cells and transgenic rat for adenocarcinoma of prostate (TRAP).…”