Skin is not only a target organ for various sex steroids and hormones, but also an endocrine organ, which produces sex steroids. It has been suggested by Nikolakis et al. that impairment in skin steroidogenesis may re...Skin is not only a target organ for various sex steroids and hormones, but also an endocrine organ, which produces sex steroids. It has been suggested by Nikolakis et al. that impairment in skin steroidogenesis may result in inflammatory or autoimmune or other skin disorders. Melanoma is one such skin disease or disorder, which is believed to be caused by UV rays. But, epidemiological, clinical, in-vivo and in-vitro studies suggested the involvement of steroids in the regulation of melanoma growth. However, these studies either did not identify the steroid involved or did not relate to the protective function of the steroid in menstruating females in melanoma, as reported by the clinical studies. In this context, our studies with mouse and human melanoma cell lines showed that female sex steroid progesterone not only inhibited melanoma cell growth, but also affected adhesion and migration functions. In addition, our studies also showed that the effect of progesterone was not a toxic or spurious, but a specific effect on melanoma cells. Hence, our in-vitro studies along with previous other studies subscribed to the idea proposed earlier by Slominski et al. that modulation of local steroids could be a new therapeutic approach for treatment of skin disease or disorder, melanoma.展开更多
Dehydroepiandrosterone (DHEA) is a weak androgen and is shown to have anti-cancer, anti-atherogenic, anti-adipogenic and anti-inflammatory effects on mouse, rat and rabbit models. However, human clinical trials data d...Dehydroepiandrosterone (DHEA) is a weak androgen and is shown to have anti-cancer, anti-atherogenic, anti-adipogenic and anti-inflammatory effects on mouse, rat and rabbit models. However, human clinical trials data did not support animal findings and were inconclusive. These systemic differences in biological actions between rodents and humans were attributed to the low level of DHEA in rodents. In order to further understand the differences in biological functions between rodents and humans, we resorted to an in-vitroapproach involving mouse, rat and human cell lines to assess DHEA biological and anabolic functions separately and independently without systemic influence. Results indicated that DHEA was effective on mouse and rat cell lines but not on human cell lines, as observed in in-vivo studies. In addition, our in-vitrostudy showed that DHEA was able to induce myogenesis in mouse mesenchymal cells revealing its anabolic function, even though DHEA was considered as a weak androgen. This observation lent credence to the ban on DHEA by IOC medical commission, citing DHEA as an anabolic steroid. These in-vitro experiments suggested that the differences in biological actions of DHEA between rodents and humans existed not only in-vivo at the systemic level, but also in-vitro at the cellular level and thus paving the way to study the mechanism responsible for these differences at the cellular level itself.展开更多
A battery of sex steroids were used to check their effect on mouse melanoma (B16F10) cell growth in-vitro. Progesterone and its synthetic receptor antagonist RU-486 showed maximum inhibition on in-vitro melanoma cell ...A battery of sex steroids were used to check their effect on mouse melanoma (B16F10) cell growth in-vitro. Progesterone and its synthetic receptor antagonist RU-486 showed maximum inhibition on in-vitro melanoma cell growth [1]. Further research work showed that the inhibition by progesterone was not a toxic, spurious or non-specific effect on mouse melanoma cell growth and the inhibition by progesterone was not mediated through progesterone receptor.展开更多
Clinical trials of weak androgen androstenedione (AD) administered at a high concentration, showed an increase in muscle mass in men like strong androgens testosterone (T) and dihydrotestosterone (DHT), but did not sh...Clinical trials of weak androgen androstenedione (AD) administered at a high concentration, showed an increase in muscle mass in men like strong androgens testosterone (T) and dihydrotestosterone (DHT), but did not show any inhibitory effect on fat mass unlike strong androgens. This observation prompted us to check the in-vitro effect of AD on adipogenesis using mouse mesenchymal multipotent cells (C3H10T1/2), which can differentiate into both myoblasts and adipocytes. Results indicated that AD inhibited adipogenesis at 10 nM, 100 nM and 1 μM concentrations, but not at 10 μM concentration. AD did not inhibit adipogenesis at 10 μM concentration and also did not inhibitmyogenesis at 10 μM concentration. Addition of bicalutamide, an androgen receptor (AR) antagonist decreased myogenesis and increased adipogenesis, indicating that the effect of AD was mediated through AR. Another weak androgen dehydroepiandrosterone (DHEA) also showed the same pattern of adipogenesis in 10T1/2 cells. AD also showed a similar pattern of adipogenesis in 3T3-L1 preadipocyte cells. Thus, the in-vitro results of AD on adipogenesis correlated with the in-vivo results of AD on fat-mass from clinical trials and suggested a possible difference in biological action between weak androgens (AD, DHEA) and strong androgens (T, DHT) on adipogenesis. Since the biological action of AD was mediated through AR, this physiological difference onadipogenesis could be due to the nature (partial agonist/antagonist) of AD binding to AR.展开更多
RU-486 is an abortifacient which is used to terminate early pregnancy. It acts by blocking progesterone receptor. In our earlier study with progesterone, RU-486 was used as a progesterone receptor antagonist to find o...RU-486 is an abortifacient which is used to terminate early pregnancy. It acts by blocking progesterone receptor. In our earlier study with progesterone, RU-486 was used as a progesterone receptor antagonist to find out the mechanism of progesterone action on melanoma cells. Results indicated that the effect of progesterone was not mediated through progesterone receptor. In the course of experiments, it was observed that RU-486 by itself inhibited mouse melanoma cell growth. Further research work with RU-486 showed a dose dependent inhibition of human melanoma cell growth. The mechanism of inhibition of cell growth was due to apoptosis and this effect of RU-486 was neither mediated through progesterone receptor nor glucocorticoid receptor. This in-vitro study suggested that melanoma also could be a target for RU-486 action, apart from breast, ovary and prostate cancers.展开更多
文摘Skin is not only a target organ for various sex steroids and hormones, but also an endocrine organ, which produces sex steroids. It has been suggested by Nikolakis et al. that impairment in skin steroidogenesis may result in inflammatory or autoimmune or other skin disorders. Melanoma is one such skin disease or disorder, which is believed to be caused by UV rays. But, epidemiological, clinical, in-vivo and in-vitro studies suggested the involvement of steroids in the regulation of melanoma growth. However, these studies either did not identify the steroid involved or did not relate to the protective function of the steroid in menstruating females in melanoma, as reported by the clinical studies. In this context, our studies with mouse and human melanoma cell lines showed that female sex steroid progesterone not only inhibited melanoma cell growth, but also affected adhesion and migration functions. In addition, our studies also showed that the effect of progesterone was not a toxic or spurious, but a specific effect on melanoma cells. Hence, our in-vitro studies along with previous other studies subscribed to the idea proposed earlier by Slominski et al. that modulation of local steroids could be a new therapeutic approach for treatment of skin disease or disorder, melanoma.
文摘Dehydroepiandrosterone (DHEA) is a weak androgen and is shown to have anti-cancer, anti-atherogenic, anti-adipogenic and anti-inflammatory effects on mouse, rat and rabbit models. However, human clinical trials data did not support animal findings and were inconclusive. These systemic differences in biological actions between rodents and humans were attributed to the low level of DHEA in rodents. In order to further understand the differences in biological functions between rodents and humans, we resorted to an in-vitroapproach involving mouse, rat and human cell lines to assess DHEA biological and anabolic functions separately and independently without systemic influence. Results indicated that DHEA was effective on mouse and rat cell lines but not on human cell lines, as observed in in-vivo studies. In addition, our in-vitrostudy showed that DHEA was able to induce myogenesis in mouse mesenchymal cells revealing its anabolic function, even though DHEA was considered as a weak androgen. This observation lent credence to the ban on DHEA by IOC medical commission, citing DHEA as an anabolic steroid. These in-vitro experiments suggested that the differences in biological actions of DHEA between rodents and humans existed not only in-vivo at the systemic level, but also in-vitro at the cellular level and thus paving the way to study the mechanism responsible for these differences at the cellular level itself.
文摘A battery of sex steroids were used to check their effect on mouse melanoma (B16F10) cell growth in-vitro. Progesterone and its synthetic receptor antagonist RU-486 showed maximum inhibition on in-vitro melanoma cell growth [1]. Further research work showed that the inhibition by progesterone was not a toxic, spurious or non-specific effect on mouse melanoma cell growth and the inhibition by progesterone was not mediated through progesterone receptor.
文摘Clinical trials of weak androgen androstenedione (AD) administered at a high concentration, showed an increase in muscle mass in men like strong androgens testosterone (T) and dihydrotestosterone (DHT), but did not show any inhibitory effect on fat mass unlike strong androgens. This observation prompted us to check the in-vitro effect of AD on adipogenesis using mouse mesenchymal multipotent cells (C3H10T1/2), which can differentiate into both myoblasts and adipocytes. Results indicated that AD inhibited adipogenesis at 10 nM, 100 nM and 1 μM concentrations, but not at 10 μM concentration. AD did not inhibit adipogenesis at 10 μM concentration and also did not inhibitmyogenesis at 10 μM concentration. Addition of bicalutamide, an androgen receptor (AR) antagonist decreased myogenesis and increased adipogenesis, indicating that the effect of AD was mediated through AR. Another weak androgen dehydroepiandrosterone (DHEA) also showed the same pattern of adipogenesis in 10T1/2 cells. AD also showed a similar pattern of adipogenesis in 3T3-L1 preadipocyte cells. Thus, the in-vitro results of AD on adipogenesis correlated with the in-vivo results of AD on fat-mass from clinical trials and suggested a possible difference in biological action between weak androgens (AD, DHEA) and strong androgens (T, DHT) on adipogenesis. Since the biological action of AD was mediated through AR, this physiological difference onadipogenesis could be due to the nature (partial agonist/antagonist) of AD binding to AR.
文摘RU-486 is an abortifacient which is used to terminate early pregnancy. It acts by blocking progesterone receptor. In our earlier study with progesterone, RU-486 was used as a progesterone receptor antagonist to find out the mechanism of progesterone action on melanoma cells. Results indicated that the effect of progesterone was not mediated through progesterone receptor. In the course of experiments, it was observed that RU-486 by itself inhibited mouse melanoma cell growth. Further research work with RU-486 showed a dose dependent inhibition of human melanoma cell growth. The mechanism of inhibition of cell growth was due to apoptosis and this effect of RU-486 was neither mediated through progesterone receptor nor glucocorticoid receptor. This in-vitro study suggested that melanoma also could be a target for RU-486 action, apart from breast, ovary and prostate cancers.
