Hepatocellular carcinoma (HCC) is a common and deadly cancer of the liver in the United States and many other countries. New therapeutic strategies are critically needed as current therapeutic options for HCC patients are limited. MicroRNA (miRNA) modulation is a new molecular approach to treating HCC. MiRNAs are a group of gene expression regulators involved in the pathogenesis and progression of cancers when aberrantly expressed. Two miRNAs, miRNA-122 and miRNA-21, have been identified to play a major role in tumor growth and chemoresistance in HCC. Therapeutic restoration of both miRNAs has the potential to not only slow HCC growth but also render these tumors sensitive to doxorubicin. Using an ultrasound (US) and microbubble (MB) mediated drug delivery platform, we have recently demonstrated for the first time that therapeutic miRNAs can be successfully delivered into HCC in mice in vivo when the miRNAs were loaded in an FDA-approved poly(lactic-co-glycolic acid)-nanoparticle (PLGA- NP). The putative key mechanism to US and MB mediated delivery is the enhanced vascular permeability caused by acoustic cavitation, a phenomenon where MB expand, contract, and collapse violently in response to incident US. A major challenge in clinical translations of this new HCC treatment is that the larger body habitus in patients can cause significant acoustic attenuation which then leads to insufficient cavitation and poor drug delivery result in parts or the entire tumor, increasing the risk of tumor recurrence. In this proposal, we aim to achieve homogeneously enhanced drug delivery into HCC for improved clinical outcomes. We hypothesize that homogeneously enhanced delivery can be achieved when cavitation is successfully induced in the entire tumor volume. For this purpose, we will develop a new cavitation image guided drug delivery platform which allows adjustment of treatment parameters to ensure successful cavitation generation in the entire tumor. We will test this platform in orthotopic rabbit models of doxorubicin-resistant HCC. We will first evaluate the acute drug delivery profile (amount and spatial homogeneity) for the new treatment with real-time US parameter adjustment and optimization versus the conventional treatment with fixed treatment parameters. Subsequently, clinical outcomes (tumor growth, recurrence rate) after an 8-week treatment course similar to common clinical chemotherapeutic regimens will be investigated for the new versus conventional treatments and animals will be monitored up to 4 months after treatment for local recurrence. The successful completion of our research will pave the way for a novel genetic reprogramming approach for treating HCC. The approach developed in this proposal may provide homogeneously enhanced therapeutic deposition of miRNA in HCC and significantly improve treatment outcomes. Moreover, this treatment strategy may be readily adapted to deliver other miRNA therapeutics and applied to other cancers.
New approaches to treating hepatocellular carcinoma (HCC) are critically needed as therapeutic options are very limited and recurrence is common. Here, we explore a novel genetic reprogramming approach to effectively treating HCC with reduced recurrence risk by delivering therapeutic microRNAs using an image- guided ultrasound and microbubble facilitated drug delivery platform. Guided by a roadmap predicting the treatment outcomes in real-time, this approach allows adjustment and optimization of therapeutic delivery into the entire tumor, thereby reducing the risk of recurrence from inappropriately treated regions.
