Project description:Epidemiologic studies demonstrate that women from cultures that consume high levels of dietary soy have reduced breast cancer rates compared to women from cultures where soy consumption is typically much lower. The types of soy products consumed can also differ with Asian cultures consuming primarily minimally refined soy products while Western cultures often consume more highly refined soy products such as isolated soy protein (ISP). Our previous work showed that lifetime exposure to a diet containing 20% ISP promoted mammary tumor development in MTB-IGFIR transgenic mice. In this study, lifetime exposure to lower levels of ISP were evaluated (5% ISP and 1% ISP) to determine whether more moderate levels of ISP could protect against mammary tumorigenesis. A standard rodent diet, Teklad 2018 was also included in this study and Teklad 2018 contains a less refined form of soy, namely soybean meal. MTB-IGFIR mice fed ISP diets, independent of the concentration, displayed increased mammary tumor incidence and reduced tumor latency compared to MTB-IGFIR mice fed a 20% casein diet. Unexpectedly, MTB-IGFIR mice fed Teklad 2018 were completely protected against mammary tumor development. Although RNA sequencing of mammary tumors from ISP or casein fed mice did not identified gene expression patterns associated with the ISP diets, the ISP diets consistently promoted the expression of contractile related proteins in pubertal mammary glands. Therefore, lifetime exposure to ISP may alter gene expression in pubertal mammary glands rendering them more susceptible to transformation. Based on these findings women may want to avoid highly refined soy products such as ISP and switch to less refined forms of dietary soy until additional studies can be performed.
Project description:This study aimed to investigate the direct mechanism(s) of action ofMono-(Ethyl-Hexyl) phthalate (MEHP) on the rat fetal testis with particular emphasis to Leydig cell steroidogenesis, by means of an in vitro system based on culture for 3 days of fetal testes from 14.5 days post-coïtum old rats. We first confirmed that an exposure to MEHP led to a dose-dependent decrease of testosterone and demonstrated that dihydrotestosterone (DHT) production was also inhibited. We then demonstrated that in 10µM MEHP-exposed testis basal 17alpha-hydroxy-progesterone (17OHP) production was increased (+40%) while androstenedione levels decreased (-55%). Furthermore, the addition of the latter steroid but none of the other precursors rescued testosterone thus establishing further that MEHP specifically blocked steroidogenesis at the level of the 17,20 lyase activity of the P450c17 enzyme (CYP17), which converts 17OHP to androstenedione. Furthermore and accordingly, both levels of testicular CYP17 protein (western blot) and cyp17a1 gene (qPCR, microarrays) were found to decrease under MEHP exposure. The microarray analysis also showed that among the few other testicular genes cyp17a1 whose expression was inhibited by MEHP were the genes encoding for the Leydig cell insulin-like peptid 3 (INSL3), involved in the control of testicular descent, and for inhibin A (INHA), that regulates follicular-stimulating hormone secretion.Under in vitro conditions where MEHP is not metabolized and remains at low intratesticular concentration, our findings show in particular that this phthalate directly inhibits several important Leydig cell factors involved in testis development and function.
Project description:This study aimed to investigate the direct mechanism(s) of action ofMono-(Ethyl-Hexyl) phthalate (MEHP) on the rat fetal testis with particular emphasis to Leydig cell steroidogenesis, by means of an in vitro system based on culture for 3 days of fetal testes from 14.5 days post-coïtum old rats. We first confirmed that an exposure to MEHP led to a dose-dependent decrease of testosterone and demonstrated that dihydrotestosterone (DHT) production was also inhibited. We then demonstrated that in 10µM MEHP-exposed testis basal 17alpha-hydroxy-progesterone (17OHP) production was increased (+40%) while androstenedione levels decreased (-55%). Furthermore, the addition of the latter steroid but none of the other precursors rescued testosterone thus establishing further that MEHP specifically blocked steroidogenesis at the level of the 17,20 lyase activity of the P450c17 enzyme (CYP17), which converts 17OHP to androstenedione. Furthermore and accordingly, both levels of testicular CYP17 protein (western blot) and cyp17a1 gene (qPCR, microarrays) were found to decrease under MEHP exposure. The microarray analysis also showed that among the few other testicular genes cyp17a1 whose expression was inhibited by MEHP were the genes encoding for the Leydig cell insulin-like peptid 3 (INSL3), involved in the control of testicular descent, and for inhibin A (INHA), that regulates follicular-stimulating hormone secretion.Under in vitro conditions where MEHP is not metabolized and remains at low intratesticular concentration, our findings show in particular that this phthalate directly inhibits several important Leydig cell factors involved in testis development and function. Transcription profiling of rat fetal testes explants, vehicle or monoethylhexylphthalate (MEHP)-treated (1uM, 10uM) 3 condition experiment, 1-3 biological replicates per treatment. 2 technical replicates per sample.
Project description:Drugs used in chemotherapy work in different ways to stop cancer cells from dividing so they stop growing or die. This phase I trial is studying the side effects and best dose of 17-N-allylamino-17-demethoxygeldanamycin in treating patients with advanced epithelial cancer, malignant lymphoma, or sarcoma