Research Article Analysis of Immune Cells from Human Mammary Ductal Epithelial Organoids Reveals Vd2 þ T Cells That Efficiently Target Breast Carcinoma Cells in the Presence of Bisphosphonate Nicholas A. Zumwalde 1,2 , Jill D. Haag 2 , Deepak Sharma 2 , Jennifer A. Mirrielees 3 , Lee G. Wilke 3 , Michael N. Gould 2 , and Jenny E. Gumperz 1 Abstract Developing strategies to enhance cancer prevention is a paramount goal, particularly given recent concerns about sur- gical treatment of preinvasive states such as ductal carcinoma in situ. Promoting effective immunosurveillance by leukocytes that scan for nascent neoplastic transformations represents a potential means to achieve this goal. Because most breast cancers arise within the ductal epithelium, enhancing protec- tive immunosurveillance will likely necessitate targeting one or more of the distinctive lymphocyte types found in these sites under normal conditions. Here, we have characterized the intraepithelial lymphocyte compartment of non-cancerous human breast tissue and identified a subset of T lymphocytes that can be pharmacologically targeted to enhance their responses to breast cancer cells. Specifically, Vd2 þ gd T cells were consistently present in preparations of mammary ductal epithelial organoids and they proliferated in response to zole- dronic acid, an aminobisphosphonate drug. Vd2 þ T cells from breast ductal organoids produced the antitumor cytokine IFNg and efficiently killed bisphosphonate-pulsed breast carcinoma cells. These findings demonstrate the potential for exploiting the ability of Vd2 þ gd T cells to respond to FDA-approved bisphosphonate drugs as a novel immunotherapeutic approach to inhibit the outgrowth of breast cancers. Cancer Prev Res; 9(4); 305–16. Ó2016 AACR. Introduction Identifying genetic loci associated with reduced risk of breast cancer may provide novel targets for cancer prevention (1). Such loci may operate directly within mammary epithelial cells or may be mediated by the activities of non-mammary cells. We have recently reported that the rat Mcs5a locus acts via the immune system and that the resistant allele of Mcs5a is associated with increased frequency and functional activity of gd T cells within spleen and mammary epithelium (2). These findings suggest that engaging key immune cell types to phenocopy the effects of the resistant Mcs5a allele may represent an effective breast cancer prevention strategy. However, given the substantial differences between humans and muroid rodents in the molecular specifi- cities of innate immune cells that mediate defense against incip- ient threats, an essential prerequisite to such an effort is identi- fying the immune subsets typically present in human mammary ductal epithelial tissues and determining how these can be med- ically targeted. Cancerous cells are culled from tissues through the process of immunosurveillance, whereby several different types of leuko- cytes continuously scan for neoplastically transformed cells and eliminate them (3). Because breast cancers typically originate from the epithelial cells lining the mammary ducts and lobules (4), the immune cells responsible for immunosurveillance of transformed breast cells are likely to be those that patrol the ductal epithelium. Although recent studies have illustrated the presence of leukocytes in the human breast (5–8) and even in the epithelium (6, 7), the specific leukocyte subsets within this specialized tissue niche have remained poorly characterized. Moreover, a key unanswered question is whether immune cells are present that can be targeted to promote enhanced immuno- surveillance of precancerous or cancerous cells. Conserved T lymphocyte populations are particularly attractive for this type of approach because they recognize non-polymor- phic antigen-presenting molecules and thus are present in all individuals regardless of human leukocyte antigen (HLA) type, and they can selectively be activated based on features of the T cell receptor (TCR). Some examples of conserved T lymphocytes are gd T cells, mucosal-associated invariant T (MAIT) cells, and invariant natural killer T (iNKT) cells. Based on their characteristic TCR chain usages, these types of T cells can be specifically targeted using monoclonal antibodies (mAb), or in some cases by syn- thetic compounds. 1 Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. 2 McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madi- son, Wisconsin. 3 Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. Note: Supplementary data for this article are available at Cancer Prevention Research Online (http://cancerprevres.aacrjournals.org/). Current address for D. Sharma: Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay Mumbai, India. Corresponding Authors: Jenny E. Gumperz, 1550 Linden Drive Madison, WI 53706. Phone: 608-263-6902; Fax: 608-262-8418; E-mail: jegumperz@wisc.edu; and Michael N. Gould, E-mail: gould@oncology.wisc.edu doi: 10.1158/1940-6207.CAPR-15-0370-T Ó2016 American Association for Cancer Research. Cancer Prevention Research www.aacrjournals.org 305 Research. on June 13, 2020. © 2016 American Association for Cancer cancerpreventionresearch.aacrjournals.org Downloaded from Published OnlineFirst January 25, 2016; DOI: 10.1158/1940-6207.CAPR-15-0370-T