DOI
https://doi.org/10.25772/PXYM-V055
Defense Date
2017
Document Type
Thesis
Degree Name
Master of Science
Department
Molecular Biology and Genetics
First Advisor
Masoud Manjili
Abstract
The successful treatment of breast cancer is limited due to a fraction of tumor cells escaping drug-treatment by entering a dormant state, only to relapse years or decades later at distant sites. Host-driven chronic inflammatory cells such as M2 macrophages play an important role in tumorigenesis, but the role of tumor-intrinsic inflammatory signaling involved in tumor dormancy and recurrence is unknown. We sought to determine the role of tumor-intrinsic inflammatory pathways in mouse mammary carcinoma cells (MMC) treated with Adriamycin (ADR), a clinically relevant chemotherapeutic drug. We found that ADR-induced dormant tumor cells autonomously produced pro-inflammatory cytokines, in vitro. MMC treated with Chloroquine (CQ) prior to ADR treatment displayed a delay in relapse, or prolonging of dormancy, when compared to ADR-treated MMC. Additional gene array data showed predicated activation of NF-κB p65 in ADR-treated dormant MMC that eventually relapsed. These data suggest that the anti-inflammatory function of CQ led to prolonged dormancy. To test this, we investigated the role of inflammatory signaling pathways directly by shRNA-mediated knockdown and CRISPR-Cas9-mediated knockout of NF-κB p65 in MMC. We found that knockdown of NF-κB p65 resulted in fewer dormant cells after ADR treatment and reduced rate of relapse, in vitro. NF-κB p65 was also found to reduce the immunomodulatory effects of ADR, with shNF-κB p65 showing increased upregulation of neu upon ADR treatment. Additionally, we found NF-κB p65 to be associated with a higher infiltration of CD8+ T cells and anti-tumor T cell responses. Our findings suggest a dual role of tumor-intrinsic NF-κB p65 pathway, allowing for escape from drug treatment through dormancy which leads to relapse, but also for proper lymphocyte infiltration and subsequent anti-tumor activity.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-2-2017