Master of Science, The Ohio State University, 2021, Animal Sciences

Mastitis is a key challenge for the dairy industry. Defined as inflammation of the mammary gland, mastitis is most commonly caused by a bacterial intramammary infection (IMI). A large proportion of dairy heifers have an IMI prior to calving and beginning their first lactation. An infection during this time is expected to be deleterious to the growth and development of the mammary gland (quarter), diminishing future milk production and producer profitability. The objectives of these works were to describe the effects an IMI has on primigravid heifer mammary secretions, determine if prepartum administration of an internal teat sealant (ITS) in heifers reduced the odds of IMI at calving, and determine if administration of ITS earlier (75 vs 35 days prepartum) differentially affected the odds of IMI at calving. A total of 270 heifers were utilized. Aseptic secretion samples were obtained from one quarter of every heifer at 75 days prepartum and another quarter of every heifer at 35 days prepartum. Immediately following sampling, the designated quarter was administered ITS. The other 2 quarters of every heifer were not interfered with prior to calving. After calving, each quarter of every heifer was sampled. Both prepartum secretion as well as colostrum samples were bacterially cultured to determine quarter infection status and the somatic cell count (SCC) was enumerated. Prepartum secretion samples were scored based on viscosity as thick or thin. At 75 days prepartum, 26% of quarters had an IMI, and 28% were infected at 35 days prepartum. Uninfected secretion samples were 133.2 (95% confidence interval (CI): 16.8 - > 999.9) times more likely to be thick compared to samples infected with a major pathogen, and 14.3 (95% CI: 8.5 - 24.1) times more likely to be thick compared to samples infected with non-aureus staphylococci (NAS). Secretion SCC was elevated when an IMI was present within the quarter; quarters with an IMI caused b (open full item for complete abstract)

Committee: Benjamin Enger (Advisor); Jessica Pempek (Committee Member); Craig Zimmerly (Committee Member) Subjects: Animal Sciences

Master of Science, The Ohio State University, 1922, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2022, Animal Sciences

The dairy cow requires a fully grown and developed udder to produce copious amounts of milk during lactation. Most mammary growth and development occurs during the animal's first gestation, however coupled at this time is the increased prevalence of intramammary infections (IMI). Such IMI are expected to impair mammary growth and shortchange development, negatively impacting future milk production. Dairy heifers represent a significant financial investment for producers and therefore should enter first lactation healthy so that they yield maximal return on investment. However, how these IMI affect mammary gland growth and development in rapidly growing and developing mammary glands has not been investigated. The objectives of these works were to histologically compare uninfected and Staphylococcus aureus-infected mammary glands by quantifying tissue areas occupied by different tissue types and determine whether infection status affects the degree of cellular proliferation and apoptosis in rapidly growing mammary glands. Non-lactating dairy heifers (n = 16) were administered estradiol and progesterone for 14 d to stimulate mammary growth and development and 2 quarters of each heifer were either infused with Staphylococcus aureus (CHALL) or served as an uninfected control (UNINF) on d 8. Heifers were randomly euthanized on either the last day of hormonal injections (GRO), or 13 d post-injections (DEV) and mammary iii tissues were collected from the center and edge parenchymal regions of each mammary gland. In GRO tissues, CHALL quarters had less epithelial tissue area and greater tissue area occupied by intralobular stroma, coinciding with the greater percentage of apoptotic mammary epithelial cells (MEC) and lower percentage of apoptotic stromal cells compared to UNINF quarters. Additionally, edge parenchyma contained a greater percentage of apoptotic stromal cells compared to center parenchyma. Coinciding with this observ (open full item for complete abstract)

Committee: Benjamin Enger (Advisor); R. Michael Akers (Committee Member); Sheila Jacobi (Committee Member) Subjects: Animal Sciences

Master of Science, The Ohio State University, 2020, Animal Sciences

Mammary blood flow is central to mammary growth, development, and productivity, but development of the vasculature network is poorly understood. The objective of this study was to determine how the vascular system adapts to mammary growth by inducing different levels of mammary growth and examining two regions of tissue. Holstein heifer calves (n = 12) received 12 daily injections on the days immediately preceding euthanasia at 82 d of age. Treatments were control (CON), short-term estradiol (SHORT), and long-term estradiol (LONG). CON calves received corn oil injections while SHORT calves received 9 injections of corn oil followed by 3 injections of estradiol; LONG calves received 12 estradiol injections. Mammary tissues were collected from the center and edge parenchymal regions of all right rear mammary glands to quantify the tissue area of various tissue structures, the percentage of proliferating epithelial cells, and the number and form of blood vessels. Results showed that LONG calves had a greater tissue area occupied by epithelium than CON and SHORT calves, while epithelial area in CON and SHORT calves were similar. Edge parenchyma had a greater percentage of proliferating epithelial cells than center parenchyma across all treatment groups. Within the edge region, LONG calves had the greatest percentage of proliferating epithelial cells, coinciding with greater epithelial area. Blood vessel number per unit of tissue area was greater in center than edge parenchyma; the corresponding vessel surface area/unit of tissue area followed this same pattern, being greater in center parenchyma than edge parenchyma. Mammary blood vessel measures were not markedly influenced by estradiol treatment. Together, these results highlight the marked difference in the number and organization of blood vessels in different mammary parenchyma regions but indicate that estradiol's effects on stimulating mammary epithelial proliferation does n (open full item for complete abstract)

Committee: Benjamin Enger (Advisor); Maurice Eastridge (Committee Member); Luis Moraes (Committee Member) Subjects: Agriculture; Animal Sciences; Animals; Livestock; Physiology

MS, University of Cincinnati, 2020, Medicine: Biomedical Research Technology

Increasing evidence has shown the impact of external factors on increased cancer risk. The chances of being diagnosed with breast cancer increases in female patients diagnosed with diabetes and/or obesity. Lifestyle behaviors, such as diet, can impact the anatomy of the mammary gland, but the exact mechanism is not well known. In this study, we explore the anatomical changes that arise in the mammary gland in response to an unhealthy diet, specifically studying the adipocytes and epithelial cells of the mammary glands. Our hyperglycemic mouse model showed signs of diabetes and obesity and has higher risk factors for breast cancer. In addition, not only was there a reversal in obesity and diabetic phenotypes, but also in adipocyte hypertrophy. Quantification of the mammary gland lobules and proliferation showed irreversible epithelial hyperplasia. We believe that this preliminary data will lead to further studies that focuses on identifying a mechanistic link between hyperglycemia and cancer.

Committee: Anjaparavanda Naren Ph.D. (Committee Chair); Biplab DasGupta Ph.D. (Committee Member); Takahisa Nakamura Ph.D. (Committee Member) Subjects: Molecular Biology

PhD, University of Cincinnati, 2018, Medicine: Cancer and Cell Biology

Breast cancer is the most common cancer and the second leading cause of cancer-related deaths in women in the United States. Advances in early detection and treatments have improved the outcome of patients with localized/regional disease; however, more than 40,000 patients with aggressive distant breast cancers succumb to this disease each year. This highlights the lack of effectiveness of current treatments in advanced metastatic disease and the need to gain further insight of the mechanisms leading to aggressive breast cancer to develop effective therapies to prevent breast cancer progression and decrease disease mortality. Research on mammary gland development has significantly contributed to understand breast cancer, with cellular processes, cell-to-cell interactions, and pathways important for proper mammary gland development been found deregulated in breast cancer. The RON receptor tyrosine kinase and its ligand HGFL have been recently implicated in breast cancer. However, knowledge of the role of RON and HGFL in regulating mammary gland development and breast cancer progression is limited. Studies presented in this thesis have provided valuable insights that have aided our understanding of the importance and complexity of the HGFL-RON signaling in normal mammary gland development and breast cancer. Studies discussed here have identified novel HGFL-RON-mediated interactions between mammary epithelial cells/tumor cells and cells within the microenvironment that are crucial for proper mammary gland development and breast cancer progression. In addition, studies examining the role of HGFL-RON signaling in mammary gland development provided valuable information about the different cellular compartments where HGFL-RON signaling occurs and led to the studies examining the cell-type specific functions of HGFL-RON signaling in breast cancer progression. Studies discussed in this thesis revealed that activation of HGFL-RON signaling in tumor epithelial cells, breast ca (open full item for complete abstract)

Committee: Susan Waltz Ph.D. (Committee Chair); Jun-Lin Guan Ph.D. (Committee Member); Simon Hogan Ph.D. (Committee Member); Shao-Chun Wang Ph.D. (Committee Member); Susanne Wells Ph.D. (Committee Member) Subjects: Cellular Biology

Doctor of Philosophy, The Ohio State University, 2018, Comparative and Veterinary Medicine

Neonates are immune competent but immunologically immature at birth and are highly susceptible to enteric pathogens. For example, porcine epidemic diarrhea virus (PEDV) is a highly virulent re-emerging enteric coronavirus that causes acute diarrhea, dehydration and 80-100% mortality in neonatal piglets. Since its emergence in the United States (US) in 2013, PEDV caused over 8.5 million piglet deaths and $900 million to $1.8 billion in losses to US swine producers in 2014. Lactogenic immunity remains the most promising and effective way to protect neonatal suckling piglets from enteric diseases like PEDV. This is particularly true for domesticated animals like swine and cattle whose epitheliochorial placenta inhibits immunoglobulin (Ig) transfer in utero. Therefore, colostrum [first secretions from the mammary gland (MG)] and milk-derived antibodies (Abs) and other immune factors are the sole source for immune protection after birth. Passive lactogenic immunity is achieved through high titers of IgG Abs in colostrum and a continuous supply of secretory IgA (sIgA) Abs in milk. Specifically, because of their persistence in milk at high titers, sIgA Abs play a major role in conferring passive lactogenic protection against enteric pathogens in suckling neonates. Therefore, our goal was to improve the understanding of maternal and lactogenic immunity induced via the gut-MG-sIgA axis and its role in protection against PEDV in neonatal suckling piglets. Our first objective was to study the impact of stage of gestation at time of PEDV infection in pregnant gilts and its implications for generation of lactogenic immunity and protection of PEDV-challenged piglets. To understand how stage of gestation affects maternal immune responses to PEDV, three groups of gilts were orally infected with PEDV in the first, second or third trimester. Control (mock) gilts were inoculated with medium in the third trimester. To determine if lactogenic immunity correlated with protection, all (open full item for complete abstract)

Committee: Linda Saif (Advisor); Anastasia Vlasova (Committee Member); Qiuhong Wang (Committee Member); Prosper Boyaka (Committee Member) Subjects: Agriculture; Animal Diseases; Immunology; Veterinary Services; Virology

Doctor of Philosophy, Case Western Reserve University, 2018, Pathology

Human cell transformation models have provided critical insight into our understanding of the events that drive cancer development and progression. However, these models have largely ignored the contributions of cytokines that originate outside a cancer cell in the surrounding tumor microenvironment (TME). Although tumor cells exploit cytokine signaling to promote growth, invasion, and metastasis, the response of normal and premalignant cells to cytokines in the developing TME remains unclear. Continued refinement of human cell transformation models will expand our understanding of the tumor-suppressive mechanisms dismantled by developing cancer cells and lead to the identification of novel targets for future cancer therapies. The studies described here refined a transformation model that begins with normal human mammary epithelial cells (HMEC) isolated from reduction mammoplasties to investigate the mechanisms regulating the divergent responses of normal and transformed cells to the cytokine Oncostatin M (OSM). Using normal HMEC, we revealed that OSM-induced senescence requires a novel link between OSM/Signal Transducer and Activator of Transcription 3 (STAT3) signaling and Transforming Growth Factor-ß (TGF-ß)/SMAD3 signaling. Notably, constitutive c-MYC expression dismantled STAT3/SMAD3-induced senescence and cooperated with OSM to drive transformation, epithelial-mesenchymal transition (EMT), and invasion. We then utilized this HMEC model to examine how OSM/STAT3 signaling and TGF-ß/SMAD3 signaling cooperate in transformed HMEC. In contrast to normal cells, OSM did not engage senescence in transformed HMEC and instead induced the EMT-inducing transcription factor (EMT-TF) Snail, epithelial–mesenchymal plasticity, and cancer stem cell (CSC) properties. Inhibiting TGF-ß-mediated signaling or suppressing expression of SMAD3 and SMAD4, but not SMAD2, abrogated OSM/STAT3-induced plasticity and CSC properties in transformed HMEC. Finally, my studies lead to the discove (open full item for complete abstract)

Committee: Mark Jackson Ph.D. (Advisor); Hannah Gilmore M.D. (Committee Chair); Analisa DiFeo Ph.D. (Committee Member); Clive Hamlin Ph.D. (Committee Member); William Schiemann Ph.D. (Committee Member); George Stark Ph.D. (Committee Member); Zhenghe Wang Ph.D. (Committee Member) Subjects: Biochemistry; Biology; Biomedical Research; Cellular Biology; Genetics; Health Sciences; Medicine; Molecular Biology; Pathology

Master of Science, The Ohio State University, 2017, Anatomy

Due to high mortality associated with triple negative breast cancer (TNBC), a prevention program has the potential to protect many women against this disease. Recent epidemiological and meta-analysis studies revealed a possible correlation between a lack of breastfeeding and development of TNBC. African-American (AA) women have a disproportionate burden of developing aggressive TNBC, a sub-population with higher parity rates and lower prevalence of breastfeeding. The reasons for why parity and breastfeeding affect breast cancer risk are unclear, but recent studies revealed that the pregnancy-lactation cycle (which leads to remodeling of the mammary glands) alters breast morphology and microenvironment, thereby modifying breast cancer risk. Natural weaning (NW), the gradual cessation of breastfeeding, results in a measured reduction of the ductal structures, termed involution. Conversely, the decision not to breastfeed results in a hastened involution, or abrupt involution (AW). We modeled NW and AW in wild-type mice by restricting breastfeeding to 28 and 7 days respectively. Striking differences in the distribution of cell populations were observed in the mammary glands of AW mice compared to NW mice. Fluorescence activated cell sorting analysis revealed an expansion of the luminal progenitor cells with a concomitant decrease in mammary stem-cell enriched/basal compartment in the glands of the AW cohort. This observation is reminiscent of previous observations in TNBC in both animal models and human pre-neoplastic BRCA1-mutation carrier patients. The AW mammary epithelium is more proliferative, inflammatory, exhibit increased estrogen receptor expression, and is immune active 56 days postpartum. Moreover, we observed more collagen deposition in the AW glands compared with NW, which has been correlated with reduced risk for TNBC. These observations highlight a key difference between the lactating and non-lactating mammary glands at the molecular level that could pred (open full item for complete abstract)

Committee: Bhuvaneswari Ramaswamy MD (Committee Chair); Leone Gustavo PhD (Advisor); Kalmar Eileen PhD (Committee Co-Chair); Majumder Sarmila PhD (Committee Member); McHugh Kirk PhD (Committee Member) Subjects: Anatomy and Physiology; Cellular Biology; Molecular Biology; Oncology

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 1982, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 1960, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 1957, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 1956, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 2016, Molecular, Cellular and Developmental Biology

Breast cancer is the second leading cause of cancer related death women worldwide despite significant advances in detection, diagnosis and treatment. The high mortality rates with accompanying therapeutic resistance and relapse over the years can be predominantly attributed to the immense heterogeneity of breast cancer. Importantly, the tumor microenvironment, which is comprised of stromal cells including cancer-associated fibroblasts (CAFs) contributes significantly to mammary tumor heterogeneity. Specifically, fibroblasts constitute the bulk of the tumor stroma and is now acknowledged to play an important role in regulating tumor progression. However, exact signaling pathways governing the cross-talk between the tumor cells and fibroblasts remain to be elucidated. In this study, we examined the fibroblast-specific roles of the proto-oncogene Ets2 and the tumor suppressor Pten in ErbB2-driven tumorigenesis. In the first part of this study, we show that deletion of fibroblast-specific Ets2 in the ErbB2 tumor model delayed the progression of these tumors by inhibiting tumor angiogenesis. We then independently examined the function of tumor suppressor Pten within the stromal fibroblasts. Previous studies demonstrate that loss of fibroblast-specific Pten promoted ErbB2-driven tumorigenesis. To identify how PTEN null fibroblasts induce the malignant transformation of associated ErbB2+ epithelia, we evaluated both phenotypic and gene expression changes within pre-neoplastic epithelium of mice with and without stromal PTEN. (i) Fibroblast-specific PTEN deletion causes an expansion of mammary epithelial stem cell (MaSC)-enriched subpopulations and alters their stem cell activity. Specifically, MaSC-enriched basal/myoepithelial cells from stromal PTEN null mice exhibited decreased levels of NOTCH3 receptor, a key player in the maintenance of stem cell fate. Interestingly, we discovered that PTEN null fibroblasts have low JAGGED-1 expression levels, a transmembrane li (open full item for complete abstract)

Committee: Michael Ostrowski (Advisor) Subjects: Cellular Biology; Molecular Biology

PhD, University of Cincinnati, 2014, Medicine: Toxicology (Environmental Health)

The vitamin D3 receptor (VDR) is an established negative regulator of mammary gland development and breast cancer as VDR null mice exhibit enhanced epithelial growth during pubertal breast development and are more susceptible to induced carcinogenesis in the mammary gland. Furthermore, the actions of VDR in the breast are largely dependent on the ligand, vitamin D3. However, it is estimated that over 1 billion people worldwide are vitamin D3 deficient or insufficient, including millions of growing children. Despite the alarming number of people with low systemic vitamin D3 levels, little is known about the repercussions of inadequate VDR signaling during critical times of growth and development, such as mammary gland development, and future disease risk. In this dissertation, we studied the cell-type specific contributions of VDR signaling in the breast during mammary gland development and the protective role of VDR in an aggressive form of breast cancer mediated by oncogenic Ron receptor tyrosine kinase overexpression. We show that VDR signaling in both mammary epithelial cells and adipocytes govern ductal outgrowth through the regulation of epithelial cell proliferation and apoptosis within terminal end buds. Mechanistically, adipocytes secrete growth regulatory cytokines such as IL-6 in response to vitamin D3 for VDR-mediated paracrine regulation of epithelial cell fate. In the context of breast cancer, oncogenic Ron is overexpressed in roughly 50% of all human cases. Ron-mediated mammary tumorigenesis requires activation of downstream ß-catenin signaling, which we demonstrate to be antagonized by vitamin D3 through the VDR. Both mammary gland hyperplasia and tumor onset were significantly delayed with VDR signaling and correlated with decreased levels of ß-catenin target genes involved in growth regulation and invasion. Moreover, vitamin D3-dependent VDR signaling increased expression of dickkopf-related protein 1, an extracellular inhibitor of canonical Wnt/ß-c (open full item for complete abstract)

Committee: Shuk-Mei Ho Ph.D. (Committee Chair); Nira Ben-Jonathan Ph.D. (Committee Member); Mary Beth Genter Ph.D. (Committee Member); Susan Kasper Ph.D. (Committee Member); Susan Waltz Ph.D. (Committee Member); Glendon Michael Zinser Ph.D. (Committee Member) Subjects: Developmental Biology

Doctor of Philosophy, The Ohio State University, 2014, Comparative and Veterinary Medicine

Staphylococcus aureus (Staph.aureus) is the most common contagious pathogen causing intramammary infections (IMI) in cows worldwide. Although practices to control this organism have been advocated for decades, identification of risk factors is crucial in prevention and control of Staph.aureus. The objectives for Chapter 2 and Chapter 3 were to estimate prevalence of Staph.aureus in Ohio dairies and to determine the association of management practices with isolation of Staph.aureus in bulk tank milk (BTM). Questionnaire about herd characteristics, milking procedures, udder health/mastitis control, biosecurity and calf/heifer raising practices were mailed to 780 dairy producers, with a response rate of 49.2%. Staph.aureus prevalence was 48%, 64% and 69% when considering one, two or three BTM samples. Herds with somatic cell count lower than 150,000 cells/mL and milking routine practices such as pre-stripping, pre- and post-dipping and use of single towels per cow were associated with reduced detection of Staph.aureus. Dry-off practices such as abrupt cessation of milking, use of internal teat sealant or blanket dry treatment were associated with herd size. In addition to the presence of Staph.aureus in the infected udder and milk, the cow can also be colonized with the organism on body sites. The objective of the Chapter 4 was to assess the role of teat skin colonization by Staph. aureus in Staph.aureus IMI by evaluating genetic relatedness of Staph.aureus isolates from milk and teat skin of dairy cows using pulsed-field gel electrophoresis (PFGE) and characterizing the isolates based on the carriage of virulence genes. Cows in four known Staph.aureus positive herds were sampled and was found that quarters with teat skin colonized with Staph.aureus were almost five times more likely to be diagnosed with Staph.aureus IMI than quarters not colonized on teat skin. Three main clusters (A, B, C) were identified with PFGE using a cutoff at 80% similarity. All clusters conta (open full item for complete abstract)

Committee: Paivi Rajala-Schultz Dr. (Advisor) Subjects: Veterinary Services

PhD, University of Cincinnati, 2009, Medicine : Cell and Molecular Biology

The Ron receptor tyrosine kinase is overexpressed in many human cancers including colorectal and breast, and studies have established Ron as a predictor of disease outcome and as a therapeutic target. Ron overexpression and constitutive activation contributes to the tumorigenic properties of human colon cancer cells. Moreover, metastatic dissemination of colon cancer cells from primary orthotopic tumors in mice can be reduced upon Ron knockdown. The majority of hereditary and sporadic colorectal cancers harbor aberrant Apc/β-catenin signaling, however, the relationship between Ron, Apc, and β-catenin signaling in intestinal tumorigenesis is not well understood. We sought to test the requirement of Ron tyrosine kinase signaling for initiation of intestinal tumors in vivo using a well-characterized mouse model of mutant Apc-driven intestinal tumorigenesis. By generating (ApcMin/+ mice with a targeted deletion of the tyrosine kinase domain of Ron (RonTK-/-), we found that Ron is not required for intestinal adenoma formation, and that Ron loss increases tumor burden in a large fraction of mice. Unexpectedly, the loss of Ron in non-transformed intestinal epithelium significantly increases crypt cell proliferation, which may lead to an increased susceptibility to tumor initiation in this model. β-catenin localization and target gene expression were not significantly altered in ApcMin/+;RonTK-/- mouse tumors or normal intestine compared to controls, suggesting that Ron is not required for β-catenin signaling in this model. Like in colon cancer, Ron overexpression has also been observed in approximately half of human breast cancers. Mammary-specific overexpression of Ron in mice results in mammary carcinomas in 100% of mice that metastasize to the lungs and liver, supporting the conclusion that Ron overexpression is a causal oncogenic factor in breast cancer. Interestingly, mammary glands from virgin mice with aberrant Ron expression have dilated mammary ducts and sparse du (open full item for complete abstract)

Committee: Susan Waltz PhD (Committee Chair); Kathleen Goss PhD (Committee Member); Christopher Wylie PhD (Committee Member); Nelson Horseman PhD (Committee Member); Erik Knudsen PhD (Committee Member); Sohaib Khan PhD (Committee Member) Subjects: Cellular Biology

PhD, University of Cincinnati, 2009, Medicine : Molecular and Cellular Physiology

Waves of milk production, as seen during lactation, transition into milk stasis and involution of the mammary gland, upon weaning. This transition is under homeostatic control by systemic and local regulators. Significant knowledge has been gathered regarding involvement of systemic hormones in regulating involution. However, the local factors remain largely unstudied. Previously our lab discovered serotonin as a local regulator of mammary gland milk synthesis and involution. Here we explore the influence of serotonin in regulating involution associated events, especially tight junction disruption. We show that human mammary epithelial cells have an elaborate serotonin system including serotonin reuptake transporter and multiple serotonin receptors. Through this system, serotonin employs a complex signaling mechanism to mediate fine biphasic regulation of mammary epithelial tight junctions. This is important to meet the dynamic demands associated with milk stasis and involution. Further breast cancer cells show a profound change in this serotonin system (biosynthesis and receptor expression pattern). This results in a homeostatic imbalance between the suppressive vs pro-oncogenic activites of serotonin. The breast cancer cells become resistant to involution-associated suppressive actions of serotonin and enhance the pro-oncogenic effects of serotonin (through increased serotonin synthesis). Such action of serotonin support the finding that involution is associated with increased risk of breast cancer and promotes formation of aggressive tumors.

Committee: Nelson Horseman Ph.D. (Committee Chair); Arthur Buckley Ph.D. (Committee Member); H. Leighton Grimes Ph.D. (Committee Member); Stuart Handwerger M.D. (Committee Member); Susan Waltz Ph.D. (Committee Member) Subjects: Biomedical Research