Dissecting Molecular Events in Pregnancy-Associated Melanoma

Abstract

Melanoma is the number one cause of neoplasm-related death in women of childbearing age, 1,2 with peak incidence coinciding with perimenopausal age 3. With today's advancing maternal age, the incidence of pregnancy-associated melanoma continues to increase 4,5. For these reasons, we aimed to clarify the factors associated with pregnancy that may affect underlying biological mechanisms and subsequent disease progression. Three human melanoma cell lines (MM96, D04, and MM329) were exposed to pregnant and non-pregnant patient serum in order to quantify cell proliferation after 48 hours. All three cell lines demonstrated an increase in cell proliferation exposed to pregnant serum, with only MM96 showing a significant difference (p = 0.0067). Subsequent microarray analysis of cell lines exposed to pregnant and non-pregnant serum yielded five genes (ID3, DUSP5, SERPINB2, IGFBP3, and NDRG1) whose expression supported our observation of increased cell proliferation secondary to pregnant serum exposure. After subsequent qPCR studies on the five genes, only ID3 validated across both techniques, which guided further ID3 validation on a protein level. We report a consistent upregulation of ID3 in melanoma cells exposed to pregnant serum at RNA and protein level. Through this study, we argue that melanoma cell proliferation is affected by underlying gestational mechanisms that can be explained by gene expression changes in melanoma cells exposed to pregnant serum.