MR-HIFU induced drug delivery for pancreatic cancer treatment

University Of Washington, Seattle WA

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Abstract

? DESCRIPTION (provided by applicant): Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States. Surgical resection offers the only chance of cure with an about 20% 5-year survival but more than 80% of patients present with advanced unresectable disease. The overall 5-year survival rate for all types of pancreatic cancer is less than 5%. Pancreatic tumor therapy has been ineffective partly because pancreatic tumors have a dense stroma inhibiting penetration of chemotherapeutic drugs into the tumor. High intensity focused ultrasound (HIFU) can be used to induce targeted hyperthermia leading to increased perfusion potentially enhancing targeted drug delivery (TDD) to pancreatic tumors with deficient vasculature. In addition, pulsed HIFU has potential to mechanically disrupt stroma resulting in increased permeability of the dense stroma in pancreatic tumors. One major challenge with the HIFU-enhanced TDD is the absence of noninvasively assessing treatment efficacy following the HIFU application. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) have been widely used as key noninvasive methodologies for clinical tumor diagnosis and treatment follow-up due to their good spatial resolution compared to other imaging modalities. However, with respect to pancreatic tumors, conventional MRI has been used for qualitative detection of pathologic regions for diagnosis and treatment follow-up with limited resolution and inability of quantification for preclinical studies using mouse models. Therefore, more effective magnetic resonance (MR) biomarkers with high resolution are needed to monitor treatment responses of tumors treated with HIFU in tumor bearing mice. We hypothesize 1) HIFU induced hyperthermia will enhance TDD and pancreatic tumor cell death in a targeted region and quantitative MR will enable assessment of the treatment 2) pulsed HIFU will disrupt stromal layers in pancreatic tumor and MRI/MRS will assess the process of stromal layer disruption. The overall goal of this study is 1) to generate effective HIFU induced hyperthermia for targeted chemotherapeutic drug delivery for a pancreatic tumor mouse model (KPC) that closely resembles human pancreatic cancer and 2) to accurately monitor both mild hyperthermia and responses to pancreatic tumor treatments based on the HIFU-enhanced TDD using noninvasive and quantitative MRI and MRS methods at high resolution. To accomplish the study goal we propose three specific aims: 1) to assess pancreatic tumor progression for the KPC mouse model with advanced MR methods, 2) to evaluate perfusion and degree of stromal layer disruption after HIFU and 3) to assess responses to chemotherapeutic treatments mediated by HIFU. The development of noninvasive MR biomarkers, pulsed HIFU method and effective KPC mouse model will be essential to advance the understanding of this deadly disease and has the potential to be used to assess promising therapies in pre- clinical and clinical trials.