Runx1 stabilizes the mammary epithelial cell phenotype and prevents epithelial to mesenchymal transition

Runx1 is a well characterized transcription factor essential for hematopoietic differentiation and Runx1 mutations are the cause of leukemias. Runx1 is highly expressed in normal epithelium of most glands and recently has been associated with solid tumors. Notably, the function of Runx1 in the mammary gland and how it is involved in initiation and progression of breast cancer is still unclear. Here we demonstrate the consequences of Runx1 loss in normal mammary epithelial and breast cancer cells. We first observed that Runx1 is decreased in tumorigenic and metastatic breast cancer cells. We also observed loss of Runx1 expression upon induction of epithelial-mesenchymal transition (EMT) in MCF10A (normal-like) cells. Furthermore depletion of Runx1 in MCF10A cells resulted in striking changes in cell shape, leading to mesenchymal cell morphology. The epithelial phenotype could be restored in breast cancer cells by re-expressing Runx1. Analyses of breast tumors and patient data revealed that low Runx1 expression is associated with poor prognosis and decreased survival. We addressed mechanisms for the function of Runx1 in maintaining the epithelial phenotype and find Runx1 directly regulates E-cadherin; and serves as a downstream transcription factor mediating TGFbeta signaling. We also observed through global gene expression profiling of growth factor depleted cells that induction of EMT and loss of Runx1 is associated with activation of TGFbeta and WNT pathways. Thus these findings have identified a novel function for Runx1 in sustaining normal epithelial morphology and preventing EMT and suggest Runx1 levels could be a prognostic indicator of tumor progression

Runx1 stabilizes the mammary epithelial cell phenotype and prevents epithelial to mesenchymal transition

Runx1 is a well characterized transcription factor essential for hematopoietic differentiation and Runx1 mutations are the cause of leukemias. Runx1 is highly expressed in normal epithelium of most glands and recently has been associated with solid tumors. Notably, the function of Runx1 in the mammary gland and how it is involved in initiation and progression of breast cancer is still unclear. Here we demonstrate the consequences of Runx1 loss in normal mammary epithelial and breast cancer cells. We first observed that Runx1 is decreased in tumorigenic and metastatic breast cancer cells. We also observed loss of Runx1 expression upon induction of epithelial-mesenchymal transition (EMT) in MCF10A (normal-like) cells. Furthermore depletion of Runx1 in MCF10A cells resulted in striking changes in cell shape, leading to mesenchymal cell morphology. The epithelial phenotype could be restored in breast cancer cells by re-expressing Runx1. Analyses of breast tumors and patient data revealed that low Runx1 expression is associated with poor prognosis and decreased survival. We addressed mechanisms for the function of Runx1 in maintaining the epithelial phenotype and find Runx1 directly regulates E-cadherin; and serves as a downstream transcription factor mediating TGFbeta signaling. We also observed through global gene expression profiling of growth factor depleted cells that induction of EMT and loss of Runx1 is associated with activation of TGFbeta and WNT pathways. Thus these findings have identified a novel function for Runx1 in sustaining normal epithelial morphology and preventing EMT and suggest Runx1 levels could be a prognostic indicator of tumor progression

Detection of Human Herpesvirus Type-1 Antigen in Tissues of Oral Squamous Cell Carcinoma by Direct Immunofluorecent Assay

Background: Human herpesvirus is a large enveloped DNA virus and significant human pathogen. Many studies examined oral squamous cell carcinoma for herpes simplex virus and suggested an association with this virus; others have demonstrated human herpesvirus -1 DNA in different part of oral squamous cell carcinoma. Objective: To detect the human herpes virus -1 antigen in tissues of oral squamous cell carcinoma. Patients and methods: Fourty two formalin-fixed, paraffin embedded oral tissues blocks were collected from 30 patients with oral squamous cell and 12 individuals with apparently-healthy oral tissues from archives of histopathology laboratory of college of Dentistry -Baghdad University, during the period from 2010 till 2012. All samples were related to the period between 2004 to 2009. Human herpesvirus -1 antigen was detected by direct immunofluorecent assay (US biological, Cat. No. H2033-08E).  Results: Among oral squamous cell carcinoma group, 26 formalin-fixed, paraffin embedded oral tissues blocks were found to contain HHV-1 antigen, this result constituted 86.7% of the total oral squamous cell carcinoma screened for HHV-1 antigen and 75% within apparently-healthy oral tissues.  The age of patients ranged from (25-70) years with mean of 53.26 ±12.1years. The highest percentage 60% was diagnosed in the age above 50 years. The percentage in males (61.68%) was more than in females (38.31%). On the other hand there was no significant difference between viral infection, age and gender distribution, while significant correlation noticed with tumor differentiation. Conclusion: The detection of human herpesvirus -1 antigen in oral squamous cell carcinoma and apparently healthy control indicates virus with other factor such as chemicals and radiation, which play important role in the development of oral cancer

RUNX1 Control of Mammary Epithelial and Breast Cancer Cell Phenotypes

Breast cancer remains the most common malignant disease in women worldwide. Despite the advantages of early detection and improved treatments, studies into the mechanisms that initiate and drive breast cancer progression are still required. Recent studies have identified RUNX1, which is an essential transcription factor for hematopoiesis, is one of the most frequently mutated genes in breast cancer patients. However, the role of RUNX1 in the mammary gland is understudied. In this dissertation, we examined the role of RUNX1 in both normal mammary epithelial and breast cancer cells. Our in vitro studies demonstrated that RUNX1 inhibits epithelial to mesenchymal transition (EMT), migration, and invasion, reflecting its tumor suppressor activity, which was confirmed in vivo. Moreover, RUNX1 also contributes significantly to inhibition of the phenotypes of breast cancer stem cells (CSC), which is responsible for metastasis and tumor relapse. We showed that Runx1 overexpression reduces the tumorsphere formation and cancer stem cell population. Overall, our studies provide mechanistic evidence for RUNX1 repression of EMT in mammary cells, anti-tumor activity in vivo and regulation of CSC-like properties in breast cancer. Our results highlight crucial roles for RUNX1 in preventing epithelial to mesenchymal transition and tumor progression in breast cancer. This RUNX1 mediated mechanism points to novel intervention strategies for early stage breast cancer

Heregulin-Enhanced Tyrosine Phosphorylation in Breast Cancer Cells: Role of PP2A in HER-2/neu Oncogenic Signalling

Ph.DDOCTOR OF PHILOSOPH

Raman spectroscopic analysis to identify chemical changes associated with different subtypes of breast cancer tissue samples

Breast cancer incidence rates are increasing in women worldwide with the highest rates reported in developed countries. A combination of screening approaches, Immuno-histopathology and gene profiling analyses are currently used for diagnosis and typing but have their own limitations in understanding disease and its subtypes. Raman spectroscopy (RS) has attained great attention from biomedical researchers due to its non-invasive and non-destructive detection approach. Chemometrics is one of the powerful tools used in spectroscopic research to enhance its sensitivity. RS was used to characterise and differentiate two breast cancer and one normal breast cell lines (MDA-MB-436, MCF-7 and MCF-10A) and spectra of the cell lines have revealed basic differences in the concentration of biochemical compounds such as lipids, nucleic acids and proteins Raman peaks were found to differ in intensity and principal component analysis (PCA) was able to identify variations that lead to accurate and reliable separation of the three cell lines. Linear discriminant analysis (LDA) model of three cell lines was predicted with 100% sensitivity and 91% specificity. RS studies were extended from single cells to multiple cell spheroids. Human breast cancer cell lines (T-47D) were grown as spheroids and a combination of RS and Cluster analysis were employed to understand biochemical fingerprint and differentiation of normal proliferating, hypoxic and necrotic regions of spheroids. These variations may be useful in identifying new spectral markers and further understanding of cancer metabolism. Finally, Human breast biopsies on Tissue microarray (TMA) slide were analysed using RS and Chemometrics approaches. Biopsies were classified as luminal A, luminal B, HER2 and triple negative subtypes to understand chemical changes associated with breast cancer subtypes. Supervised and unsupervised algorithms were applied on biopsy data to explore intra and inter dataset biochemical changes associated with lipids, collagen and nucleic acid content. In summary, RS has offered great potential understanding breast cancer from cell line level to multicellular spheroid to higher architecture of tissue. This study has explored new area to understand biochemical fingerprint of breast biopsies, which is complementary to current trends of molecular profiling and immuno histopathological approaches