Yanrong Su

Oxidized derivative of docosahexaenoic acid preferentially inhibit cell proliferation in triple negative over luminal breast cancer cells

Omega-3 polyunsaturated fatty acids (PUFAs) exert an anticancer effect by affecting multiple cellular mechanisms leading to inhibition of proliferation and induction of apoptosis. It is well known that breast cancer comprises distinct molecular subtypes which differ in their responsiveness to therapeutic and preventive agents. We tested the hypothesis that n-3FA may preferentially affect triple-negative breast cancer cells for which no targeted intervention is presently available. The in vitro antiproliferative effects of n-3 PUFA docosahexaenoic acid (DHA) and its metabolite, 4-OH-DHA as well as its putative metabolite 4-OXO-DHA, were tested in five triple-negative human basal breast cell lines at different stages of transformation (MCF-10F, trMCF, bsMCF, MDA-MB-231, and BT-549) and three luminal breast cancer cell lines (MCF-7, T-47D, and SK-BR-3). Cell proliferation was measured with the tetrazolium MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay. DHA and its oxidized derivatives significantly inhibited cell proliferation (20–90% reduction) of both basal and luminal breast cancer cell lines. The inhibitory effect was more pronounced on triple-negative basal breast cancer cell lines as compared to luminal breast cancer cell lines after 4-OXO-DHA treatment. Our data provide novel information regarding the preferential antitumor effect of oxidized derivatives of DHA on basal type breast cancer.

Development and characterization of two human triple‐negative breast cancer cell lines with highly tumorigenic and metastatic capabilities

Triple‐negative breast cancer (TNBC) is a group of cancer with high diversity, limited therapies, and poor prognosis. TNBC cell lines and animal models provide effective tools for studies and drug discovery. Here, we report the development of two TNBC cell lines (XtMCF and LmMCF) based on our existing cell model that consists of normal breast epithelial cell line MCF10F, estradiol‐transformed cells trMCF, and Boyden chamber‐selected tumorigenic cells bsMCF. The XtMCF and LmMCF cell line were derived from xenograft and lung metastasis of bsMCF cells, respectively. The bsMCF, XtMCF, and LmMCF cells have undergone epithelial–mesenchymal transition (EMT), exhibiting a mesenchymal‐like feature. In vivo studies showed XtMCF and LmMCF cells were highly tumorigenic and metastatic. The injection of 5 × 104 cells to CB17/SCID mice mammary fat pad produced xenografts in 9/9 mice and tumors reached 10 millimeters in diameter in 5 weeks. The injection of 1 × 106 XtMCF or 8 × 104 LmMCF cells into the mice tail vein was sufficient to form extensive lung metastases in 4 weeks. The two new cell lines exhibited CD44+/CD49f+ and CD44+/EpCAM+ cancer stem cell (CSC) characteristics, and the EGF‐like domain of EpCAM was cleaved off. Together with the normal and early transformed counterparts, herein we provide a complete cancer model for the study of initiation, evolution, and identification of new therapeutics for TNBC. The finding that EGF‐like domain of EpCAM was cleaved off in cells which have undergone EMT suggests this cleavage may be involved in the EMT process and the cancer stem cell properties of these cells.

In Situ Methods for Identifying the Stem Cell of the Normal and Cancerous Breast

Stem cells are unspecialized cells with the ability of self-renewal, a high potential for proliferation, and the ability to become a variety of cell types in the body. There are basically four types of stem cells: Embryonic stem cells, which are isolated from the inner cell mass of blastocysts; adult stem cells, which are found in various tissues including umbilical cord blood, bone marrow, mammary, brain, endothelium, etc.; amniotic stem cells, which are found in amniotic fluid; and inducible pluripotent stem cells—reprogrammed cells (e.g. epithelial cells) given pluripotent capabilities. Mammary stem cells belong to adult stem cells; these cells provide the source of cells for the growth of the mammary gland during puberty and gestation. Single such cells can give rise to both luminal and myoepithelial cell types within the gland, and have the ability to regenerate the entire organ in mice. The practical definition of a stem cell is the functional definition—a cell that has the potential of self-renewal and to regenerate tissue over a lifetime. The stem cell markers used are genes or products used to isolate and identify stem cells.

Chromatin Remodeling as the New Target for Breast Cancer Prevention

Increased breast cancer incidence and mortality have been associated with nulliparity since 1700s. Pregnancy exerts a protective effect in women who delivered their first child before late 20s, when compared to women that never had a full term pregnancy. In addition, multiple pregnancies significantly decrease the risk of developing breast cancer after 50 years of age. This chapter addresses the mechanisms that determine the long lasting preventive effect of pregnancy against breast cancer, how to mimic this protective effect using pregnancy-hormones or smaller targeting molecules, and the participation of chromatin remodeling in breast cancer prevention.

Imaging Techniques for Evaluation In Vitro Behavior of Normal and Cancerous Breast Tissue

Among the in vitro imaging techniques of greatest use in cancer research are flow cytometry (FCM), immunofluorescence microscopy, and in situ hybridization (ISH).

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

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