Project Grant F31CA294974

A MECHANOIMMUNOLOGICAL BASIS FOR METASTATIC SITE PREFERENCE - THIS PROPOSAL OUTLINES A THREE-YEAR TRAINING PLAN IN CELLULAR IMMUNOLOGY AND MECHANOBIOLOGY, OFFERING THE APPLICANT DIVERSE EXPERTISE IN THESE FIELDS. THE SPONSOR'S LABORATORY EXCELS IN MODELING IMMUNE RESPONSES IN RELATION TO BIOPHYSICAL FEATURES OF TARGET CELLS, AND THE INSTITUTIONAL STRENGTHS IN IMMUNOLOGY, MECHANOBIOLOGY, AND CELL BIOLOGY CREATE AN EXCEPTIONAL TRAINING ENVIRONMENT CONDUCIVE TO SUCCESS. METASTASIS OCCURS IN A VARIETY OF ORGANS WITH VARYING MECHANICAL STATES. IN RECENT YEARS, THE BIOPHYSICAL PROPERTIES OF THESE MICROENVIRONMENTS HAVE EMERGED AS AN INFLUENCER OF METASTATIC SITE PREFERENCE (MSP) VIA MUTUAL BIOMECHANICAL CROSSTALK WHERE CANCER CELLS MIMIC THE STIFFNESS OF THEIR ENVIRONMENTS', OTHERWISE KNOWN AS MECHANORECIPROCITY. OUR PRELIMINARY DATA HAS SHOWN THAT CYTOTOXIC LYMPHOCYTES, COMPRISING OF CYTOTOXIC T CELLS AND NATURAL KILLER CELLS, SELECTIVELY DESTROY STIFFER CANCER CELLS DURING METASTATIC DISSEMINATION, A PROCESS THAT WE CALL MECHANOSURVEILLANCE. OUR STUDY COMBINES BIOPHYSICAL MEASUREMENTS WITH IN VIVO MODELS, DEMONSTRATING THAT MICROENVIRONMENTAL STIFFNESS INFLUENCES IMMUNE VULNERABILITY, IMPACTING THE ORGAN DISTRIBUTION OF METASTATIC OUTGROWTH. IN-DEPTH ANALYSES OF METASTATIC CELLS FROM DIFFERENT ORGAN SITES, UTILIZING ATOMIC FORCE MICROSCOPY AND SINGLE-CELL RNA SEQUENCING, INDICATE THAT MICROENVIRONMENTAL STIFFNESS SHAPES IMMUNE DISCRIMINATION. SPECIFICALLY, BONE METASTASES EXHIBIT INCREASED STIFFNESS, WITH THE GENE SPP1 PLAYING A ROLE IN MAINTAINING THIS STIFFNESS. FURTHER STUDIES USING CRISPR-BASED KNOCKOUT SYSTEMS SHOW THAT LOSS OF SPP1 SOFTENS CANCER CELLS. THIS SUGGESTS MECHANOSURVEILLANCE TARGETS STIFF ORGAN METASTASES, FORMING A BIOPHYSICAL BASIS FOR METASTATIC SITE PREFERENCE. BUILDING ON THESE PRELIMINARY OBSERVATIONS WE PROPOSE THAT MICROENVIRONMENTAL STIFFNESS DICTATES THE EFFICACY OF MECHANOSURVEILLANCE AND THAT THIS RELATIONSHIP SHAPES BOTH METASTATIC SITE PREFERENCE AND THE POWER OF ANTI-TUMOR IMMUNOTHERAPY. WE WILL INVESTIGATE THIS HYPOTHESIS IN TWO SPECIFIC AIMS. AIM 1 EMPLOYS IN VIVO MOUSE MODELS TO EXAMINE HOW DISTINCT MICROENVIRONMENTS AFFECT CANCER CELL MECHANICS, TRANSCRIPTOMICS, AND IMMUNE VULNERABILITY. SPECIFIC GENES, INCLUDING SPP1, WILL BE MANIPULATED TO EXPLORE THEIR ROLE IN MECHANOSURVEILLANCE. AIM 2 UTILIZES SYNTHETIC CANCER CELL NICHES TO INVESTIGATE IF ENVIRONMENTAL STIFFNESS INDEPENDENTLY CONTROLS MECHANOSURVEILLANCE EFFICIENCY. THE SUCCESSFUL COMPLETION OF THESE AIMS COULD IDENTIFY BIOMARKERS GUIDING ANTITUMOR IMMUNOTHERAPY AND INFORM NOVEL STRATEGIES FOR TREATING METASTATIC GROWTH, ADVANCING KNOWLEDGE TO ENHANCE HUMAN HEALTH.