Abstract 1977: Chemokines expression in an in vitro model of melanoma brain metastasis

Melanoma brain metastasis is still a great challenge. This work aimed to characterize the secretion profile and understand the possible role of chemokines in a xenogeneic in vitro model of melanoma brain metastasis. Brain primary mixed cultures from cerebral cortex were prepared from the neonates Wistar rats and maintained at 37°C, 5% CO 2 until 80% of confluency and maturity. Melanoma lineages used were UACC62 and SKMEL-28. Co-cultures were performed to study the direct interactions between melanoma and cortical cells. The indirect effects in the cerebral microenvironment were evaluated through conditioned medium (CM) from brain cells on melanoma lineages. It was used an early CM collected at 24h (CM24) and a late CM collected after 48h (CM48), whose both were incubated during more 24h (24CM24 and 24CM48) or 48h (48CM24 and 48CM48) on melanoma cultures. The chemokines IP10, CCL5 and IL8 were studied through Cytometric Bead Array (CBA),MIG and CCL2 also, however their values were undetectable. After the characterization of the model, IP10 was silenced to evaluate its influence in the model. CBA demonstrated that in SKMEL-28 the late soluble factors during 48h (48CM48) were capable of rase IP10 levels (p=0,0286). On the other hand, direct and indirect contact with brain cells reduced IL8 levels, compared to SKMEL28 alone with respectively p = 0.02 and p=0,0286, where both chemokines were not detected. On UACC62, IP10 levels were higher only in the co-culture (p=0,02), suggesting the need of contact between the different cells. Also, IL8 was decreased in all conditions compared to UACC62. After IP10 silencing, SKMEL-28 presented higher levels of IL8 in 48CM48. On UACC62, the IP10 silencing resulted in elevation of IL8 levels when the cells were in co-culture. RANTES did not present alterations in its levels in any of the conditions after IP10 knock-down. The IP10 silencing was also capable of impair the transwell invasion of SKMEL-28 in the presence of CM24 and CM48. Together, these results confirmed that IP10 alters IL8 levels, but no RANTES in a mimetic microenvironment of melanoma brain metastasis. Furthermore, IP10 is capable of influencing SKMEL-28 migration in this xenogeneic model. More studies to better understand the role of IP10 and IL8 in the establishment of melanoma brain metastasis in this model are in progress. Citation Format: Renata Santos, Maria Clara Sampaio, Amanda Albuquerque, Michelly Pereira, Maira Pitta, Moacyr Rego. Chemokines expression in an in vitro model of melanoma brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1977.