Cisplatin affects testicular steroidogenesis trough a mechanism that involves ROS-mediated P450scc inhibition

SUAREZ, G.; MORI SEQUEIROS GARCIA, M.; ACQUIER, A.; BRION, L.; GOROSTIZAGA, A.; GOMEZ, N.; MENDEZ, C.F.; PAZ, C.

Rio de Janeiro

Congreso; 13th International Congress of Endocrinology; 2008

International Society of Endocrinology

Platinum compounds (PtC) such as carboplatin (Cp), oxaliplatin (Ox) and cisplatin (Cs) are drugs widely used in the treatment of different cancers, including testicular and ovarian tumours. The different PtC affect steroidogenesis in varying degrees. However, the mechanism involved in this effect is not fully established. The aim of this work was to analyze the in vitro toxicity of Cp, Ox and Cs on testicular steroidogenesis and to study the involved mechanism. Mouse interstitial testicular cells were incubated (5 h) with Cp, Ox or Cs (50µM), under basal conditions (C) or following stimulation with hCG or 8Br-cAMP and testosterone (T) production was quantified by RIA. Cs significantly inhibited (p<0.05) T production (ng/ml) in basal (C=9.0 ± 2.8; C+Cs=5.1 ± 1.6) and stimulated (hCG=150.3 ± 23.3; cAMP=126.9 ± 35.4; hCG+Cs=106.6 ± 22.0; cAMP+Cs= 71.0 ±  15.0) conditions, while Cp and Ox had no effect. The site of action of Cs on T production was studied using different steroidogenic substrates. A freely diffusible cholesterol analogue (22R-hydroxycholesterol, 22R), and pregnenolone (P5) were used as P450scc and 3b-Hydroxysteroid dehydrogenase substrates respectively. Cs significantly inhibited (p< 0.05) 22R-supported T production (22R=32.0 ± 4.1; 22R+Cis=15.5 ± 3.1) while it produced a non-significant inhibition of P5-supported T synthesis. A reactive oxygen species (ROS)-generating compound, 2,2´-Azobis (2-methylpropionamidine) dihydrochloride (ABAP) also inhibited 22R-supported T synthesis (22R+ABAP=12.4 ± 4.1) and a hydrophilic analogue of alpha-tocopherol, Trolox (Tx), abrogated this effect (p<0.05). Moreover, Tx blocked also Cs effect on 22R-supported T production (22R+Cs+Tx=34.0 ± 3.3; 22R+Tx=29.7 ± 3.4). Similar results were obtained when the effect of PtC on steroidogenesis was studied on MA-10 Leydig cells. Long term exposure of MA-10 cells to PtC inhibited cell proliferation and induced apoptosis in a magnitude comparable to the effect of this compounds on steroid production. MAP kinase/ MAP kinase phosphatase pathways are also activated by Cs. However, the effect was detected after long term exposure to the drug, suggesting an indirect action of Cs on that pathway. Toghether, our results show that Cs exerts an acute citotoxic effect on testicular steroid synthesis through ROS generation and inhibition of P450scc enzymatic activity. The activation of MAP kinases after prolonged Cs treatment might be due, at least in part, to Cs-induced ROS generation.