MON-312 Biochemical Basis of Steroid Hormones Action on Human Melanoma Cell Growth In-Vitro and Its Clinical Implication

Abstract

: Clinical study showed that menstruating females were better protected in melanoma than post-menopausal women and men of any age. However, the study did not correlate with steroid status in females. Literature showed that progesterone (P) level varied in menstruating females between 1000 to 1500 ng/dL. Whereas in post-menopausal women, progesterone ranged between 20 to 100 ng/dL and in males between 27 - 90 ng/dL. Our earlier in-vitro research showed that progesterone significantly inhibited human melanoma (BLM) cell growth. So, it was hypothesized that progesterone could be the molecule protecting menstruating females in melanoma. Further research showed that androgens (androstenedione, AD and testosterone, T) also inhibited human melanoma cell growth in-vitro, but only at high concentrations (100 μM and 200 μM). Co-incubation of AD and T separately with P showed an additive effect on human melanoma cell growth inhibition with as low as 10 μM concentration of progesterone, suggesting the protective function of progesterone. As literature showed that progesterone action was mediated through cytokines, Elisarray was used to check the biochemical basis of P, AD and T actions on BLM cells. Elisarray showed that there was a specific suppression of IL-8 cytokine in the supernatants of AD, P and AD+P co-incubated cells compared to control cells. Decrease in IL-8 was quantitated by Elisa, which displayed a direct correlation with decrease in BLM cell growth. In order to confirm the above findings, all the experiments were repeated on another human melanoma 1205Lu cell line. There was a specific suppression of IL-8 in the supernatants, as shown by both Elisarray and IL-8 Elisa. To further consolidate the findings, action of another androgen T, P and T+P were checked on both BLM and 1205Lu cell lines. Again a specific suppression of IL-8 was observed in the supernatants by Elisarray. In addition, Kanda and Watanabe already showed that dihydrotestosterone and estrogen also suppressed IL-8 in melanoma cells. Conclusion: All the tested steroids specifically suppressed IL-8, resulting in the suppression of melanoma cell growth. So, IL-8 could be playing an important role in melanoma growth. In fact, our in-vitro study involving curcumin pre-treatment already showed that IL-8 was the molecule involved in the regulation of human melanoma cell growth. So, IL-8 could be considered as a target for melanoma treatment.