RU486 inhibits expression of lysophosphatidic acid induced glycodelin.

Objective: This study was undertaken to provide evidence for the mode of action of RU486 on glycodelin produced in K562 cells. To show that histiocytes may be a source of glycodelin in leiomyoma.

Study Design: With the use of K562, a leukemia cell line, the effect of lysophosphatidic acid (LPA), RU486, antioxidants, and ZK112,993 on glycodelin protein and gene expression was studied. Immunocytochemistry for glycodelin and HAM-56 (macrophage) was performed on leiomyoma and myometrium.

Results: Incubation of K562 cells with LPA, progesterone, ZK112,933 and RU486 significantly induced the expression of glycodelin protein and messenger RNA. The addition of RU486 to LPA activated cells markedly reduced expression of glycodelin. Addition of ZK112,993, an antiprogestin without antioxidant properties, to LPA activated cells did not reduce glycodelin. Histiocytes in leiomyoma and myometrium co-localize with glycodelin.

Conclusion: RU486, partly acting as an antioxidant, markedly reduces LPA stimulated glycodelin production. Histiocytes in leiomyoma and myometrium immunostain for glycodelin and suggests a source for glycodelin in leiomyoma.