Effect of Wnt5a on aggressiveness of ER-positive breast cancer and cancer cell migration through JNK-ALCAM pathway.

Abstract

11614 Background: Wnt5a is a representative ligand that activates β-catenin-independent pathways and involved in cell motility and cell polarity, and the like, being mediated by JNK. We elucidated the implication of Wnt5a expression in breast cancer. Methods: One hundred seventy eight breast cancer patients (mean age ± SD: 60.0 ± 13.2 years) with clinical Stage I-III between January 2011 and February 2014, were prospectively evaluated. We examined relationships between Wnt5a expression and clinicopathological factors by immunohistochemical analyses. 5-year relapse-free survival rates and sites of recurrence were analyzed. In addition, molecules induced by Wnt5a in cultured cells were identified by DNA microarray analysis. Results: Wnt5a expression was significantly more frequent when estrogen receptor (ER) was present, 68/153 (44%) than when ER was absent, 1/25 (4%) (P <0.001) (Table). In ER-positive breast cancer, a significant interaction between expression of Wnt5a with lymph node metastasis (P<0.001), high nuclear grade (P=0.004), and lymphatic invasion (P=0.001). 5-year relapse-free survival rates were 81.1% and 100% in Wnt5a-positive and Wnt5a-negative breast cancers, respectively (P = 0.024). All recurrent breast cancer patients in this study had bone metastasis. We established MCF7 stably expressing Wnt5a (Wnt5a/MCF7 cells) and microarray analyses identified several genes induced by Wnt5a (>3.0 fold), involving activated leukocyte cell adhesion molecule (ALCAM). ALCAM is known to be related with apoptosis, invasion and prognosis of breast cancer. We focused on ALCAM and investigated its protein expression by Western blotting, and found remarkable increase of ALCAM in Wnt5a/MCF7 cells. Conclusions: Wnt5a expresses in ER-positive breast cancer and is associated with high-grade malignancy and a poor prognosis through JNK-ALCAM pathway. Wnt5a could be a novel prognostic factor of ER-positive breast cancer. [Table: see text]