Molecular Imaging and Theranostics of Cancer

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Achieving cancer cure, or even control, continues to be a major unanswered challenge in health care despite the remarkable technological advances of the 21st century. Advances in multi-modal noninvasive molecular and functional imaging are providing unique opportunities to expand our understanding of cancer, an understanding that is critical to developing effective and cancer specific treatments. In this resubmission I have chosen three interactive focus areas within the tumor microenvironment (TME), the tumor macroenvironment (TMacE), and Theranostics, that will be pursued in triple negative breast cancer (TNBC) and pancreatic ductal adenocarcinoma (PDAC) human tumor xenografts and syngeneic tumors in immune competent mice. In the TME focus, we will use imaging to expand our understanding of the focal adhesion kinase (FAK) mechanotransduction pathway in the metastatic cascade that will include developing PET imaging probes to detect FAK noninvasively. FAK also plays a role in tumor immune suppression. In the TMacE focus we will expand our efforts in understanding PDAC induced cachexia that results in a wide range of symptoms affecting the function of organs such as muscle, liver, brain, and heart, causing significant morbidity. The tumor secretome holds the key to this syndrome by influencing the `macroenvironment'. We will focus on characterizing the tumor interstitial fluid (TIF) in preclinical PDAC xenograft models to develop biomarkers of cachexia and identify potential metabolic targets that will be pursued through the Theranostic focus. In the Theranostic focus we will direct our efforts and expertise in imaging and NP technology to improve the outcome of checkpoint inhibitors in TNBC and PDAC. Lack of effector T-cell tumor infiltration has been identified as a major cause of the poor response to these inhibitors. We will use FDA approved poly(lactic-co-glycolic acid) PLGA to create cancer cell membrane (CCM) coated `immunosome' NPs embedded with granulocyte macrophage colony-stimulating factor (GM-CSF) to increase effector T cell tumor infiltration, and apply molecular imaging to detect the biodistribution of the NPs and the changes in T cell infiltration. Ultimately we want to use the patients own cancer cells to synthesize the NPs for personalized medicine. Since FAP-α expressing cancer associated fibroblasts (CAFs) are known to create an immune suppressive TME, we will use anti-FAP-α antibody conjugated to the near infrared (NIR) dye IR700 to detect CAFS with NIR imaging and eliminate them selectively in the tumor with PIT. If PIT of FAP-α expressing CAFs results in increased cytotoxic T cells in tumors, this may have significant applications in combination with checkpoint inhibitor treatment. We will use siRNA delivery with dextran based biocompatible NPs to downregulate FAK, and metabolic targets identified in the TMacE focus. I have built a strong network of collaborators that include clinical oncologists, radiologists, pathologists and surgeons that will ensure the rapid translation of the research conducted through the R35 award to benefit cancer detection and treatment.