Cancer is the second leading cause of death in the U.S., annually claiming over half a million lives. Thus, there is an acute need for improved non-invasive disease diagnostics and more effective drug delivery techniques that minimize toxic side effects. Engineered bacteria have been shown to safely accumulate in tumor tissue with high selectivity and treat cancers that are not responsive to conventional therapies in mouse cancer models. However, clinical success has been rare due to insufficient tumor colonization by bacteria. This is presently attributed to the host immune response, and bacteria-neutrophil interactions in particular have been implicated in several in vivo studies. Nonetheless, interactions of neutrophil and bacteria within the tumor microenvironment remain largely unexplored. This CAREER award focuses on fundamental research in bacteria-neutrophil interactions in a three-dimensional (3D) disease model with the goal of modulating these interactions in order to overcome the immunologic barrier to successful bacteria-based cancer therapy. The proposed CAREER research and education plan has the potential to revolutionize the quality of life by enabling novel cancer treatment pathways, while providing the opportunity to integrate research elements and discoveries into multidisciplinary educational and outreach experiences.
The overarching goal of the research component of this CAREER proposal is to biomanufacture a system based on controlled self-assembly of live, attenuated tumor-targeting bacteria with leukotoxin-loaded nanoparticles in order to enable localized control of bacteria-immune cell interactions within the tumor microenvironment. It is hypothesized that controlling intratumoral inflammation through localized modulation of neutrophil-bacteria interactions will enable bacteria to overcome the immunologic barrier to proliferation in viable tumor tissue. Fundamental studies on cell-cell interactions in engineered 3D disease models will be performed and means for controlling such interactions will be developed. The following research objectives will be pursued: (1) Biomanufacture and characterize a first-of-its-kind Nanoscale Bacteria Enabled Immune Modulation System (NanoBEIMS) for localized and in-situ disabling of the immunologic barrier to intratumoral proliferation of bacteria; (2) Investigate the role of the mutual effects of bacteria biofilm formation and neutrophil stimulation in intratumoral colonization of bacteria; and (3) Quantify enhancement in bacterial proliferation in tumors caused by NanoBEIMS-enabled localized depletion of neutrophils. The new knowledge gained through this interdisciplinary effort will provide a unique repertoire of enabling technologies for localized cell-cell interaction modulation, as well as highly-targeted theranostic applications for cancer therapy and beyond. Knowledge of the immune system-bacteria interactions is also critical to elucidating the underpinnings of bacterial oncogenesis and enabling effective cancer immunotherapy as well as bacteria-mediated gene therapy. The main goals of the educational component of this CAREER plan are to enhance recruitment and retention of the socioeconomically disadvantaged and ethnically underrepresented groups in STEM and to prepare future scientists to tackle complex multidisciplinary challenges in biotic/abiotic systems engineering (BASE). To this end, this CAREER proposal will establish a multi-tier plan centered on research-inspired learning. The three major components of the plan include: (1) research and training opportunities for elementary school students and teachers from a rural county in southwest Virginia, (2) web-based interactive learning modules to introduce 9-12 year old children to non-traditional areas in engineering at the national level; (3) multidisciplinary research experience for community college students with special focus on underrepresented undergraduates.
