Abstract 4066: Glycodelin abolishes PMA-induced migration of MCF-7 breast cancer cells

Abstract Glycodelin is a lipocalin protein mainly expressed in well-differentiated epithelial cells in reproductive tissues. Previously, glycodelin has been shown to induce cell differentiation in endometrial and breast cancer cells. We have used glycodelin-transfected MCF-7 breast cancer cells to study the glycodelin-induced differentiation. Glycodelin expression changed the cellular morphology towards normal, less malignant direction. In addition, glycodelin-producing cells formed significantly smaller tumors in xenograft mice. We have found that the effects of glycodelin are at least partly mediated by repressed PKCδ activity, rendering the cells resistant to activation of phorbol 12-myristate 13-acetate (PMA), a known activator of PKCδ. Here we continued these previous studies by addressing the effect of glycodelin on the invasion and migration of MCF-7 breast cancer cells, and studying the affected signaling route in more detail. Activation of signaling proteins was detected with an antibody array of 43 phospho kinases. Cell migration was studied using wound healing test. The cells were grown on chamber slides until they formed a monolayer and then a scratch was made using a pipet tip. After addition of PMA or DMSO control, the migration of the cells was monitored under microscope. In some of the control cells, PKCδ was down-regulated with RNAi prior the migration assay. For invasion through Matrigel basement membrane preparation, a Boyden chamber assay was used. The cells were grown with and without PMA and the amount of invasive cells was quantified. Phospho-kinase array did not reveal any widespread changes in the amount of phosphorylated signaling molecules between the glycodelin-producing and control cells irrespective of the PMA treatment. However, in addition to PKCδ some changes were found in the levels of phosphoproteins such as p38α and p27. In wound healing test PMA caused a two-fold increase in the migration of the control cells, but had no effect on the glycodelin-producing cells. When the expression of PKCδ was blocked in the control cells using siRNA, the addition of PMA did not increase the migration of the cells. PMA also increased the invasiveness of the cells, but that was detected in both cells clones regardless of glycodelin expression. Without PMA treatment both glycodelin-expressing and control cells behaved similarly in wound healing and invasion tests. In conclusion, glycodelin abolished PMA-induced migration in MCF-7 breast cancer cells, while it did not have any effect on the invasion of the cells. Our results suggest that the effect of glycodelin in migration is mediated by reduced activation of PKCδ. Citation Format: Laura C. Hautala, Riitta Koistinen, Hannu Koistinen. Glycodelin abolishes PMA-induced migration of MCF-7 breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4066. doi:10.1158/1538-7445.AM2014-4066