Professor, Department of Obstetrics & Gynecology and Women's Health (Reproductive Endocrinology and Infertility)
Louis Goldstein Swan Chair in Women's Cancer Research
My laboratory has two overlapping but distinct areas of research:
1. The Tumor Microenvironment
2. Mechanisms of action of estrogen and progesterone in controlling cell division in vivo.
We take a broad approached to studying these problems but with a central focus on using mouse genetics to dissect the molecular mechanisms in vivo. We also use high throughput methods such as DNA microarray based approaches and novel in vivo imaging methods to define cellular interactions and the novel signaling pathways involved in these interactions. Furthermore, we concentrate on translating our fundamental observations to clinical practice. To cover these areas we have a well funded laboratory staffed by senior fellows, post-doctoral fellows, graduate students, clinical fellows and technicians that allows us to cover many different areas of expertise. In the last year and a half five students graduated from the laboratory including two MD/PhD students. We are also well represented both by publications with over a dozen front covers of journals representing our research as well as coverage in major text books of cell biology and cancer. Furthermore in the last year Dr. Pollard gave invited talks at fifteen different conferences ranging in topics from cancer to implantation.
A brief synopsis of the Pollard’s labs research interests is given below:
(1) Tumor Associated Macrophages Promote Tumor Progression and Metastasis
Many hematopoietic cells, particularly those of the innate immune system, populate the tumor microenvironment. Of these both clinical observations and our genetic experiments in mouse models of beast cancer have indicated that macrophages play a pivotal role in enhancing tumor progression and metastatic potential (Joyce and Pollard, 2009). Our mechanistic studies indicate that these tumor-associated macrophages regulate the angiogenic switch required for the malignant transition and also promote tumor cell invasion, migration and intravasation through reciprocal EGF and CSF-1 signaling (Condeelis and Pollard, 2006; Lin and Pollard, 2007; Pollard, 2004, 2008, 2009). Furthermore, we have recently identified a sub-population on macrophages that are required for metastatic seeding and persistent growth at distant sites (Qian et al., 2009).
The lab is focused upon defining unique sub-sets of macrophages that promote different aspects of tumor progression and metastasis and in elucidating the fundamental mechanisms behind these actions. We are using novel mouse genetic and virus based tools developed in our lab to interfere with signaling pathways in vivo to define the function of these pathways in the metastatic progression of tumors. Further we are studying the evolution of the immune system during tumor development to determine how the tumors escape from being rejected and focus on the role of macrophages in these processes. The identification of these mechanisms of tumor promotion by macrophages will allow us to novel therapeutic approaches to inhibit tumor progression and malignancy.
(2) Regulation of cell proliferation by female sex steroid hormones.
Exposure to estrogen is the major risk factor for endometrial and breast cancer. This carcinogenic effect is thought to be due to the induction by this hormone of continuous cycles of epithelial cell proliferation that allows the fixation of spontaneously occurring oncogenic mutations. In contrast progesterone exposure reduces the risk of these cancers. In the uterus of mice and humans estrogen stimulates epithelial cell proliferation while progesterone completely blocks this estrogen-induced proliferation. We have used biochemical and genetic approaches in mice to identify the mechanisms of action of these sex steroid hormones. We have identified two pathways stimulated by estrogen and inhibited by progesterone that are required for the estrogen-induced mitogenic effect. The first of these is through IGF-1 signaling activating cyclin D1 mobilization into the nucleus while the second involves licensing of DNA replication through the regulation of the function of Minichromosome Maintenance proteins (MCMs) (Pan et al., 2006; Zhu and Pollard, 2007). To extend these studies to humans we have developed a program to obtain endometrial biopsies and have used laser capture microdissection of epithelial tissue to confirm similarities in hormone control of gene transcription between the two species. Further we have been able to xenograft human endometrial tissue into mice where it forms functional endometrial structures that responds to humans and which allows for biochemical analysis (Polotsky et al., 2009). Using all these techniques, we have identified novel hormone regulated signaling pathways that are deregulated in human endometrial proliferative diseases such as endometriosis and cancer and that may therefore act as therapeutic targets.
Current studies are to further elucidate the downstream cascade of transcriptional regulatory proteins that are induced by estrogen and progesterone that are involved in the regulation of cell proliferation. We also have a significant set of studies in understanding the roles of Micro RNAs in the regulation of hormone action. These are pursued at the biochemical and genetic levels and we are currently developing novel genetic tools in which to study sex steroid hormone action.
Macrophages and Cancer:
Qian, B., Deng, Y., Im J-H., Muschel, R., Zou, Y., Lang, R., Pollard, J.W., (2009) A distinct macrophage population mediates metastic breast cancer cell extravavasation, establishment and growth. PLoS ONE. Volume 4, Issue 8; 1-6.
Wyckoff, J.B., Wang, Y., Lin, E.Y., Li, J., Goswami. S., Stanley, E.R., Segall, J.E., Pollard, J.W., and Condeelis, J. (2007) Direct visualization of macrophage assisted tumor cell motility and intravasation in mammary tumors.Cancer Research: 67, 2649-2656 (Cover article).
Lin, E.Y. Li, J., Bricard, G., Wang, W., Deng, Y, Sellers, R., Porcelli, S.A., Pollard, J.W. (2007) VEGF restores delayed tumor progression in tumors depleted of macrophages. Molecular Oncology 1: 288-302 (Cover Article)
Lin, E.Y., Li, J., Gnatovskiy, L., Deng, Y., Zhu, L., Grzesik, D.A., Qian, H., Xue, X., and Pollard, J.W. (2006) Macrophages Regulate the Angiogenic Switch in a Mouse Model of Breast Cancer. Cancer Research: 66: 11238 - 111246 (Cover Article).
Qiu, X., Zhu, L., Pollard, J.W., (2009) Colony Stimulating Factor-1 Dependent Macrophage Functions Regulate the Maternal Decidual Immune Responses Against Listeria Monocytogenes Infections during Early Gestation in Mice. Infection and Immunity. 77, 85- 97
Barber, E. and Pollard, J.W. (2003) The Uterine NK Cell Population Requires IL-15 but These Cells Are Not Required for Pregnancy nor the Resolution of a Listeria monocytogenes Infection. Journal of Immunology. 171: 37-46
Sex Steroid Hormonal Regulation of the Cell Cycle
Polotsky, A.J., Zhu, L., Santoro, N., Pollard, J.W., (2009) Lithium Chloride Treatment Induces Epithelial Cell Proliferation in Xenografted Human Endometrium. Human Reproduction 2009. 24, 1960 - 1967.
Zhu, L., Pollard, J.W. (2007) Estradiol-17b Regulates Mouse Uterine Epithelial Cell Proliferation through Insulin like Growth Factor-1 signaling. Proceedings of the National Academy. 104: 15847-15851 (Winner of the Einstein Zondek award in Endocrinology)
Pan, H., Deng,Y., Pollard, J.W., (2006) Progesterone blocks Estrogen-induced DNA Synthesis through the Inhibition of Replication Licensing. Proceedings of the National Academy of Sciences: 103: 14021-14026.
Chen, B., Pan, H., Zhu, L., Deng, Y and Pollard, J.W. (2005) Progesterone Inhibits the Estrogen-Induced Phosphoinositide 3-Kinase -> AKT -> GSK-3b -> Cyclin D1 -> pRB Pathway to block Uterine Epithelial Cell Proliferation. Molecular Endocrinology 19: 1978 -1990
More Information About Dr. Jeffrey Pollard
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Albert Einstein College of Medicine
Jack and Pearl Resnick Campus
1300 Morris Park Avenue
Chanin Building, Room 601
Bronx, NY 10461
Nature.com interviews Dr. Jeffery Pollard about a new study that links a common gut bacterium, e. coli, to cancer in mice.
WABC-TV interviews Dr. Jeffrey Pollard about his research on how macrophages, immune system cells that normally protect against disease, actually help the spread of breast cancer.