Noninvasive High-Resolution Mapping of HCC Tumor Biology Predictive of Malignancy

PROJECT ABSTRACT: Hepatocellular carcinoma (HCC) is an aggressive malignancy representing the 7th most common cancer globally and the 4th most common cause of cancer death worldwide. Although magnetic resonance imaging (MRI) represents a common HCC diagnostic and prognostic tool, MRI fails to provide insights into HCC risk stratification, and does not allow for rational therapeutic allocation. Chemical exchange saturation transfer (CEST) molecular MRI, on the other hand, permits noninvasive measurement of tumor metabolism predictive of malignancy. Integration of CEST MRI into clinical HCC management has the potential to radically alter clinical practice paradigms through: (1) identification of small malignant nodules and those with unconventional enhancement features to increase diagnostic performance; (2) improved prediction of tumor aggressiveness to inform patient prognosis and treatment stratification; and (3) monitoring of tumor metabolism in patients post therapy to differentiate between pseudoprogression—characterized by tumor regression following an initial increase in tumor burden—and true tumor progression. This proposal employs the innovative Oncopig Cancer Model—a transgenic porcine model that recapitulates human cancer through induced KRASG12D and TP53R167H expression—to test the hypothesis that noninvasive mapping of in vivo creatine (Cr) metabolism empowers prediction of differential HCC tumor aggressiveness. Combining our innovative Oncopig Cancer Model with MRI and CRISPR protocols optimized under our previously funded R03 and R21 grants, we will image Oncopig HCC tumors engineered to display differential Cr metabolism and malignant potential to demonstrate that Cr CEST MRI can accurately differentiate: 1) HCC malignancy due to intertumor genetic heterogeneity, 2) intratumor heterogeneity, and 3) pseudoprogression from true tumor progression. Genes targeted will include the ubiquitous mitochondrial Cr kinase (CKMT1), which converts ATP and Cr to ADP and phosphocreatine to meet cellular energy demands. CKMT1 knockdown reduces human HCC proliferation and migration in vitro, while increased CKMT1 serum levels are associated with poor prognosis following radiofrequency ablation. We plan to test our hypothesis by pursuing the following specific aims: (1) Demonstrate applicability of Cr CEST MRI for stratifying HCC malignancy reflective of intertumor genetic heterogeneity. (2) Demonstrate applicability of Cr CEST MRI for assessment of intratumor heterogeneity. (3) Demonstrate applicability of Cr CEST MRI to differentiate between pseudoprogression and true tumor progression. Oncopig HCC tumor growth and Cr levels will be quantified using a respiratory gated liver CEST MRI protocol to reduce motion artifacts. MRI-guided biopsy collection will enable co-registration—based comparison of in vitro measurements with Cr CEST for assessment of Cr CEST sensitivity and specificity. This proposal will radically alter HCC clinical practice paradigms by enabling noninvasive high-resolution in vivo molecular profiling to improve HCC diagnostic performance, treatment stratification, and treatment response monitoring.