Blood-based biomarker amplification using high intensity focused ultrasound (HIFU

描述(申请人提供)：良性前列腺增生症(BPH)和前列腺癌是老年男性非常常见的前列腺疾病，目前的非侵入性筛查工具，如前列腺特异性抗原(PSA)测试，往往无法区分这两者。这一失败导致了广泛使用前列腺活检来获取组织样本进行组织学检查。这一过程不仅令人不适，令人不快，而且容易出现并发症，而且由于前列腺癌的多灶性，假阴性率很高。开发可靠的前列腺癌血液生物标记物将消除侵入性活组织检查的需要，但仍是一个尚未满足的挑战。最近，一类小的调控RNA-microRNAs-作为前列腺癌诊断和预后的血液生物标志物显示出巨大的前景。然而，根据迄今报道的研究，这项技术的敏感性太低，不具有临床意义。高强度聚焦超声(HIFU)治疗是一种非侵入性的消融方法，来自体外或经直肠的超声能量可以集中在体内，在不影响周围组织的情况下诱导病灶组织的热变性。最近提出了一种新型的HIFU照射，旨在诱导组织的纯机械性侵蚀，即组织摩擦。这种类型的曝光利用高度非线性的短HIFU脉冲在几毫秒内在焦点处诱导局部沸腾。对组织的腐蚀性损伤是由沸腾气泡的爆炸及其与HIFU场的相互作用造成的。这项提议的最终目标是使用HIFU对选定的区域进行局部靶向溶解。 前列腺将导致细胞内容物释放到细胞外空间，并增加循环中组织特异性microRNA的浓度。因此，基于微小RNA的测试对诊断前列腺疾病的敏感性将显著提高。因此，这种联合技术可称为“非侵入性活组织检查”。该建议的具体目标是：1)表征与经直肠应用相关的HIFU源的高幅、非线性声输出；2)观察HIFU在透明组织模拟凝胶模体和3)不同脉冲方案的体外组织中产生的侵蚀效应；4)在体内小动物肿瘤模型中优化和应用HIFU照射导致局部组织溶解；5)确定HIFU诱导的小动物模型局部肿瘤溶解后循环中肿瘤特异性microRNA的浓度是否增加。申请这一职业发展奖的候选人(Tatiana Khokhlova，PhD)的长期研究目标是优化这种非侵入性活检技术，将相应的HIFU设备改造为经直肠工作，并将这一概念转化为临床有用的方法来执行非侵入性前列腺活检。华盛顿大学的研究环境包括医学超声(应用物理实验室、工业和医学超声中心)、微生物学(弗雷德·哈钦森癌症研究中心)和医学(医学院)的专家，是实现这一目标的完美选择。Khokhlova博士是一位超声波物理学家和工程师，在超声波技术的医疗应用领域有广泛的工作经验。这种跨学科背景使Khokhlova博士能够成功地与临床医生和科学家合作。Khokhlova博士计划从事新型治疗性超声技术的研究，继续目前与弗雷德·哈钦森癌症研究中心和儿童医院的合作，从而与科学家和临床医生建立联系，并促进更快地将令人兴奋的医学超声新发展直接转化为临床。申请该奖项的主要原因是允许Khokhlova博士在生物技术和内科医学方面获得进一步的专业知识，并在三位非常成功的研究人员Joo Ha Hwang、Lawrence Crum和Muneesh Tewari的指导下发展成为一名独立的研究人员。

DESCRIPTION (provided by applicant): Benign prostate hyperplasia (BPH) and prostate cancer are very common prostate conditions in elderly men, and current non-invasive screening tools, e.g., Prostate Specific Antigen (PSA) tests, often fail to differentiate between the two. Ths failure leads to extensive use of prostate biopsies to obtain tissue samples for histological examination. Not only is this procedure uncomfortable, unpleasant and prone to complications, the rate of false negatives is high due to the multifocal nature of prostate cancer. Development of reliable blood-based biomarkers for prostate cancer would eliminate the need for invasive biopsies, but still remains an unmet challenge. Recently a class of small regulatory RNAs - micro-RNAs - has shown great promise as a blood-based biomarker for prostate cancer diagnosis and prognostication. However, according to the studies reported to date, the sensitivity of this technique is too low to be clinically relevant. High intensity focused ultrasoud (HIFU) therapy is a non-invasive ablation method, in which ultrasound energy from an extracorporeal or trans-rectal source can be focused within the body to induce thermal denaturation of tissue at the focus without affecting surrounding tissues. A novel type of HIFU exposure designed for inducing purely mechanical erosion of tissue, viz., histotripsy, was recently proposed. This type of exposure utilizes highly nonlinear short HIFU pulses to induce localized boiling at the focus in as fast as a few milliseconds. Erosive damage to tissue is produced by the explosion of the resulting boiling bubble and its interaction with the HIFU field. The ultimate goal of this proposal is to use HIFU for localized targeted lysis of selected areas of the prostate that will lead to the release of cell contents into the extracellular space and increae the concentration of tissue-specific micro-RNAs in the circulation. Thus, the sensitivity of micro-RNA-based tests for diagnosis of prostate conditions will be significantly enhanced. This combined technique may thus be termed "non-invasive biopsy". The Specific Aims of this proposal are: 1) characterize high amplitude, nonlinear acoustic outputs of the HIFU sources relevant to trans-rectal applications, 2) observe the erosive effect produced by HIFU in transparent tissue-mimicking gel phantoms and 3) ex-vivo tissue with different pulsing protocols, 4) optimize and apply HIFU exposures causing localized tissue lysis in a small animal tumor model in-vivo and 5) determine if the concentration of tumor-specific micro-RNAs in the circulation is enhanced following HIFU- induced localized tumor lysis in a small animal model. The long-term research goal of the candidate applying for this Career Development Award (Tatiana Khokhlova, PhD) is to optimize this non-invasive biopsy technique, transform the corresponding HIFU device to work trans-rectally, and translate the concept into a clinically useful approach to perform non-invasive biopsy of the prostate. The research environment at the University of Washington that includes experts in medical ultrasound (Applied Physics Laboratory, Center for Industrial and Medical Ultrasound), microbiology (Fred Hutchinson Cancer Research Center) and medicine (School of Medicine) is perfect for achieving this goal. Dr. Khokhlova is an ultrasound physicist and engineer, and has worked extensively in the field of medical applications of ultrasound technology. This interdisciplinary background enables Dr. Khokhlova to successfully collaborate with both clinicians and scientists. Dr. Khokhlova plans to pursue research in novel therapeutic ultrasound technologies, to continue current collaborations with the Fred Hutchinson Cancer Research Center and Children's Hospital, and thus be connected with both scientists and clinicians and facilitate more rapid transfer of the exciting new developments in medical ultrasound directly into the clinic. The primary reason for applying for this Award is to permit Dr. Khokhlova to gain further expertise in biotechnology and internal medicine and to develop into an independent investigator while being mentored by three highly successful researchers, Drs. Joo Ha Hwang, Lawrence Crum, and Muneesh Tewari.