Therapeutic miRNA Modulation of Hepatocellular Carcinoma Using Ultrasound Guided Drug Delivery

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Hepatocellular carcinoma (HCC) is a common and deadly cancer of the liver with increasing incidence in the United Stated. New therapeutic strategies are critically needed as current treatment options are limited, particularly for those who are resistant to doxorubicin and other chemotherapies. MicroRNAs (miRNAs) are potent gene expression regulators that when aberrantly expressed, play a profound role in cancer development and progression. Two miRNAs, miRNA-122 and miRNA-21, have been identified to play a major role in tumor growth, metastasis and chemoresistance in HCC. Therapeutic restoration of both miRNAs functions by supplementing oligonucleotide mimics of endogenous miRNA-122 and inhibiting overexpressed miRNA-21 with antisense-miR-21 (antimiR-21) has the potential to not only slow HCC growth and metastasis, but also sensitize these tumors to doxorubicin. A key challenge, however, is the ability to deliver these agents homogenously and with high efficiency into tumor cells in vivo. 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. However, to achieve efficient cancer drug delivery therapy with minimal recurrence rates from insufficiently treated regions, a spatially homogeneous delivery pattern in the tumors is critical. We hypothesize that a homogeneous delivery pattern of miRNA-122 and antimiR-21 can be achieved when cavitation is successfully induced in the entire tumor volume, resulting in strong direct anticancer effects and sensitizing HCC cells to doxorubicin chemotherapy. We will develop and test a new motion- compensated US-guided drug delivery platform with a real-time passive cavitation-imaging-based quantitative feedback algorithm implemented on the US system in the tumor volume. Guided by this imaging roadmap, adjustment of several treatment parameters will be possible in real-time during the treatment to ensure homogeneous and efficient therapeutic miRNA delivery with favorable long-term treatment effects in HCC. Furthermore, we will assess any immunomodulatory effects of our treatment approach in a syngeneic HCC model in immunocompetent mice. Also, as a next step towards clinical translation, we will move this therapeutic approach from small to a larger animals (rabbits) and will combine it with transcatheter hepatic arterial administration to approximate current clinical liver-directed therapies. The successful completion will pave the way for a novel genetic reprogramming approach for treating doxorubicin-resistant HCC that targets aberrantly expressed miRNA and implies synergistic effects with conventional chemotherapy such as doxorubicin. Therapeutic miRNA modulation may fulfill the current therapeutic void for HCC patients. Moreover, this treatment strategy may be readily adapted to deliver other therapeutics to HCC and to other cancers.