Abstract B035: The role of αB-crystallin in chemotherapy-induced migration of triple negative breast cancer

Background: Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer marked by higher rate of metastasis and poorer overall survival. Although chemotherapy is the standard care of TNBC, clinical reports have shown that neoadjuvant chemotherapy treatment promoted metastasis in TNBC patients. Neoadjuvant chemotherapy-induced pro-metastasis in breast cancer cells was well explained by tumor microenvironment of metastasis, while its intracellular process has not been clarified yet. One of the small heat shock proteins, αB-crystallin, showed its high expression in metastatic sites of TNBC comparing to primary site, suggesting that αB-crystallin might be a potential target of metastasis. Even through researchers have also showed that αB-crystallin promoted tube formation, the relationship between αB-crystallin and chemotherapy-induced metastasis is not clear and the intracellular role of αB-crystallin needs to be explored. Purpose: To identify whether αB-crystallin involves in chemotherapy treatment and how αB-crystallin works in induced metastasis in this study. The expression of αB-crystallin in chemotherapy-induced TNBC migration were examined and its influence in Epithelial-Mesenchymal Transition (EMT) markers was confirmed. Methods: Cell viability of chemotherapy (Cisplatin, Fluorouracil, or Paclitaxel) in HCC1806 were tested by wst-8 assay. Preformed wound healing assay to measure migration ratio after treating HCC1806 cells with chemotherapy of three concentrations and confirming cell confluence. Expression level of αB-crystallin was examined after the same treatment, and the migration ability was measured when silencing αB-crystallin with small interfering RNA. Expression level of αB-crystallin and EMT markers were examined by western blotting after the same chemotherapy treatment. Results: The results of wst-8 assay showed that low concentrations of chemotherapy (0.01 μM and 0.1 μM of cisplatin, 0.01 μM and 0.1 μM of fluorouracil, 0.5 nM and 1 nM of paclitaxel) have no impact on cell viability of HCC1806, and high concentration of chemotherapy (1 μM of cisplatin, 1 μM of fluorouracil, 2 nM of paclitaxel) led to 80% alive cells comparing to non-treatment group. In addition, to identify the role of αB-crystallin in chemotherapy-induced migration, wound healing assay and western blotting were performed, showing that low concentration of chemotherapy treatment induced migration and promoted αB-crystallin expression, and that high concentration of chemotherapy blocked cell migration. Moreover, EMT markers were examined by western blotting after chemotherapy treatment, the increase of N-cadherin and decrease of E-cadherin were showed in HCC1806 after low concentration of chemotherapy treatment. Finally, to confirmed the relationship between αB-crystallin and chemotherapy-induced migration, wound healing assay was performed after silencing αB-crystallin and treating with chemotherapy. Silencing αB-crystallin reversed migration of HCC1806 cells and the expression of N-cadherin and E-cadherin induced by low concentrations of chemotherapy. Conclusion: These results suggest that the treatment of low concentrations of chemotherapy promoted epithelial to mesenchymal transition through increasing αB-crystallin expression, and induced migration in HCC1806. Citation Format: Lili YANG, Kazuma HIGASHISAKA, Yuya HAGA, Naoki SEKINE, Kotoe KIYOMOTO, Ying LIN, Hirofumi TSUJINO, Kazuya NAGANO, Yasuo TSUTSUMI. The role of αB-crystallin in chemotherapy-induced migration of triple negative breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B035. doi:10.1158/1535-7163.TARG-19-B035