Dr. Shivani Soni, Co-Leader (ASU)
Dr. Upender Manne, Co-Leader and mentor (UABCCC)
Title: Molecular pathogenesis of colorectal cancer
Summary: The primary goal of this preclinical translational proposal is to determine the role of erythroblast macrophage protein (Emp) in tumor progression and to establish its prognostic and predictive value for colorectal cancers (CRCs). Secondary goals are a) to develop the career and enhance the professional activities of Dr. Shivani Soni, an early stage investigator at Alabama State University (ASU), who is seeking more experience in cancer research, and b) to continue the newly established research collaboration between ASU, a minority institution serving racial/ethnic and underserved communities, and the University of Alabama at Birmingham Comprehensive Cancer Center (UAB CCC). This relationship was created with a vision to reduce cancer health disparities through cancer research, training, and education for researchers serving at ASU. Outcomes of this collaborative study have formed the basis for the current proposal. Emp (gene ID: 10296; symbol, MAEA), was first identified in the laboratory of the Co-Leader’s (Dr. S. Soni) earlier mentor (Dr. Manjit Hanspal) in cultures of human peripheral blood erythroid progenitors. By utilizing gene-targeting technology, Dr. Soni demonstrated that Emp is involved in erythroblast enucleation and macrophage development. Directional cell migration, an indispensable characteristic of living systems, is involved in embryonic development, homeostasis, tissue remodeling, and wound healing. Abnormalities in these processes can lead to pathologic conditions, including cancer. Cell migration is a characteristic of macrophages, a heterogeneous population of cells performing tissue-specific and niche-specific functions, including phagocytosis and immune surveillance. Further, the functions of macrophages, and their contribution to the local microenvironment in pathophysiological conditions such as cancer, points to the need to elucidate Emp interactions and associated signaling pathways and thereby to identify new molecular targets for therapy. Our findings related to Emp have defined its role in monocyte/macrophage development and cell division and have demonstrated changes in subcellular localization of Emp (perinuclear to plasma membrane) during maturation of macrophages. These changes are consistent with its function as an adhesion molecule. Its presence in the nuclear matrix suggests that Emp is involved in growth and differentiation of these cells. Tumor-associated macrophages (TAMs) are involved in progression of several human malignancies, including CRC6. However, the temporal and/or spatial role of Emp in TAMs is not clear. Our preliminary data show that Emp interacts with β1 integrin, a protein that maintains the integrity of the actin cytoskeleton. Reorganization of the actin cytoskeleton is necessary for maintaining cell shape, for cell motility, and for invasion during metastasis. Moreover, extracellular matrix (ECM) remodeling and aberrant integrin signaling are associated with malignancy. Consistent with these observations, our preliminary findings demonstrate changes in immunophenotypic expression, increasing from adenomas (premalignant lesions), to primary and metastatic CRCs. Based on these findings, we hypothesize that Emp is a component of protein complexes and a structural or signal transductional link between β1 integrin and the cytoskeleton and that it is involved in CRC progression. Thus, we propose to determine the role of Emp interactions with adhesion molecules for cell-ECM attachment, for molecular cross-talk, for effects on the tumor microenvironment, and for its function in progression of CRCs. To test our hypothesis, we propose three specific aims.
Aim-1. To determine the interaction of Emp with β1 integrin within focal adhesion plaques and its involvement in tumor progression.
Aim-2. To verify the involvement of Emp with the actin cytoskeleton, in ECM functions, and in metastasis.
Aim-3. To establish the prognostic and predictive value of Emp in CRCs.
Overall Impact: The proposed experiments will (a) utilize the strengths of the Co-Leaders in establishing the role of Emp in tumor progression through its molecular interactions with β1 integrin and its effects on the actin cytoskeleton and other components of the ECM; (b) assess the predictive and prognostic value of Emp in CRCs; and (c) provide an opportunity for Dr. Soni to have mentorship and guidance by Dr. Manne in conducting translational studies, preparing manuscripts, and transitioning into an independent investigator (see mentoring plan, attached as an Appendix). Our research on the mechanisms of Emp and β1 integrin signaling in tumor progression is expected to find new molecular determinants that contribute to tumor progression and to identify therapeutic targets.
Dr. Manoj Mishra, Co-Leader (ASU)
Dr. Ponnzhagan Selvarangan, Co-Leader and mentor (UABCCC)
Title: Role of TGF beta and regulatory T cells in prostate cancer progression and clearance
Summary: The primary goal of this proposed work is to determine the role of TGF-β and regulatory T cells (TR) in prostate tumor progression and to establish the function of immune cells in prostate cancer (PCa) progression and clearance. Secondary goals are a) to develop the career and enhance the professional activities of Dr. Manoj Mishra, a new investigator at Alabama State University (ASU), who is seeking more experience in cancer research, and b) to continue the newly established research collaboration between ASU, a minority institution serving racial/ethnic and underserved communities, and the University of Alabama at Birmingham Comprehensive Cancer Center (UAB CCC). This relationship was created with a vision to reduce cancer health disparities through cancer research, training, and education for researchers serving at ASU. Outcomes of this collaboration have formed the basis for the current proposal.
Prostate cancer (PCa) is the most common non-skin malignancy and commonly diagnosed cancer, and second most cancer responsible for death in men in United States. Prior studies in animal models of PCa as well as in humans, demonstrated that the prostate produces various growth factors. Addition or blocking of these growth factors can alter the PCa cell proliferation and other important functions. Among these growth factors, transforming growth factor-β1 (TGF-β) involved in tumorigenicity, displays potent immunosuppressive activities, and is required for the conversion of conventional CD4+ T cells to FoxP3+ regulatory T cells (TR). TR cells that expresses the transcription factor Foxp3 are essential for normal immune function. Absence of TR cells results in multi-organ autoimmunity and death. Although the functions of TGF-β in tumor microenvironment have been extensively explored but a clear role of TGF-β and its effect on TR cells during PCa initiation, progression and treatment lacks experimental evidences. Hence, an understanding of function of TGF-β and its effect on TR cells during tumor progression and clearance is needed to successfully develop a targeted therapy to reduce number of TR cells in the tumor microenvironment.
In the proposed effort, we plan to elucidate the underlying mechanisms involved in the context of TGF-β and/or TR cells by use of PCa cell lines, derived from derived from transgenic adenocarcinoma of the mouse prostate (TRAMP), in C57/B6 mice. These cell lines, TRAMP-C1 and TRAMP-C2 cell lines form tumors while TRAMP-C3 cells fail to form tumor. These cell lines of PCa can be used to obtain the long-term goal of this project, which is to address the fundamental question; Do TR cells and/or TGF-β levels relate to differences in tumorigenicity of the TRAMP cell lines (C1, C2, and C3)? Our objectives are to define the role of TGF-β production by host cells in response to or TGF-β expression by TRAMP cell lines and to establish the function of TGF-β on the conversion of naïve CD4+ T cells to Foxp3-expressing TR cells. The following hypothesis-driven specific aims will reveal important mechanisms for TR cells and/or TGF-β in prostate tumorigenicity:
Specific Aim 1. To elucidate the role of TGF-β in tumorigenicity and the influence of TGF-β on the conversion of CD4+ T cells to Foxp3 TR cells.
Hypothesis: The capacity of TRAMP-C1 and TRAMP-C2 cells to form tumors is mediate by their enhanced TGF-β production, and the inability of TRAMP-C3 cells to induce tumors is mediated by suppression of TGF–β.
Specific Aim 2. If Foxp3+ TR cells modulate the responses of NK and conventional T cells to TRAMP-C1, TRAMP-C2, and TRAMP-C3 tumor cells.
Hypothesis: Reduced production of TGF-β by TRAMP-C3 cells promotes a vigorous NK cell and T cell immune response by reducing the TGF β dependent, conversion of CD4+ T cells to Foxp3+ T cells.
Overall Impact: The proposed specific aims will (a) utilize the strengths of the Co-Leaders in establishing the role of TR cells in the PCa microenvironment their effects on NK and CD8 T cells; (b) assess the predictive and mechanistic value of TR cells in PCas; and (c) provide an opportunity for Dr. Mishra to have mentorship and guidance by Dr. Ponnazhagan in conducting translational studies, preparing manuscripts, and transitioning into an independent investigator (see mentoring plan in the career development section). This research will allow us to develop a targeted therapy to reduce the number of TR cells in the tumor microenvironment.