Abstract 423: Epigenetic reprogramming of epithelial-mesenchymal transition in triple-negative breast cancer cells with DNA methyltransferase and histone deacetylase inhibitors

Abstract

Abstract Incidence and mortality of triple negative breast cancer (TNBC) are increasing in women under the age of 40 who develop metastases in response to the epithelial to mesenchymal transition (EMT). The purpose of this study is to determine if the process of EMT can be abrogated by the use of DNA methytransferase (DNMT) and histone deacetylase (HDAC) inhibitors. For this purpose, we used two triple negative breast epithelial cell lines which represent a basal breast cancer progression model [Cancer Res 67 11147-11157, 2007]: 1) the trMCF cell line, which was transformed from MCF10F cells by treatment with 70 nM 17-β-estradiol, and 2) the bsMCF cell line, which was derived by Boyden chamber selection of invaded trMCF cells. trMCF cells express E-cadherin, form ducts and masses in 3D collagen matrix, and colonies in agar methocel, but are not tumorigenic when injected in SCID mice. bsMCF cells express high levels of vimentin, low levels of E-cadherin, are highly invasive, have lost ductulogenic capacity in 3D collagen matrix, show high colony formation in agar methocel, and are tumorigenic and metastatic when injected into the tail vein of SCID mice. We tested two DNMT inhibitors: Decitabine (DAC) and SGI-110 (SGI), and two HDAC inhibitors: Vorinostat (SAHA) and JNJ-26481585 (JNJ) for four days on the trMCF and bsMCF cell lines. The growth IC50 was calculated after four days of treatment using the MTT assay. Then, cells treated with the IC50 dose were used for wound healing, Matrigel invasion, 3D culture in collagen, and colony formation assay in agar methocel. Changes of EMT markers were evaluated both by immunocytochemical staining and Western blot analysis.The growth IC50 calculated by MTT assay were as follows: 300 nM for DAC in both cell lines; 1000 nM for SGI in trMCF, 500 nM for SGI in bsMCF; 300 nM for SAHA in trMCF, 700 nM for SAHA in bsMCF; 15 nM for JNJ in trMCF, and 25 nM for JNJ in bsMCF. Our results revealed that DNMT inhibitor SGI-110 was the best drug to reverse EMT of TNBC by inhibiting cell motility, invasion, and colony formation in agar methocel, as well as promoting cell differentiation by increasing the expression of E-cadherin, and down regulation of vimentin, and SLUG. These results suggest that this new generation of DNMT inhibitor is superior to previous DNMT and the HDAC inhibitors tested. (This work was supported by The Pennsylvania Cancer Cure Grant 6914101 and by NIH core grant CA06927 to Fox Chase Cancer Center. The compound SGI-110 was provided by Astex Pharmaceutical, Inc. Dublin CA). Citation Format: Yanrong Su, Nathan R. Hopfinger, Thomas J. Pogash, Theresa D. Nguyen, Julia Santucci-Pereira, Jose Russo. Epigenetic reprogramming of epithelial-mesenchymal transition in triple-negative breast cancer cells with DNA methyltransferase and histone deacetylase inhibitors. [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 423. doi:10.1158/1538-7445.AM2014-423