Publications

Publications

Comparing efficiency of micro-RNA and mRNA biomarker liberation with microbubble-enhanced ultrasound exposure.

By:
Contributors: Robert Paproski, PhD
Ultrasound Med Biol. 2014 Sep;40(9):2207-16. doi: 10.1016/j.ultrasmedbio.2014.05.005. Epub 2014 Jul 9.

Abstract

Blood biomarkers are potentially powerful diagnostic tools that are limited clinically by low concentrations, the inability to determine biomarker origin and unknown patient baseline. Recently, ultrasound has been shown to liberate proteins and large mRNA biomarkers, overcoming many of these limitations. We have since demonstrated that adding lipid-stabilized microbubbles elevates mRNA concentration an order of magnitude compared with ultrasound without microbubbles, in vitro. Unfortunately the large size of some mRNA molecules may limit efficiency of release and hinder efficacy as an ultrasound-liberated biomarker. We hypothesize that smaller molecules will be released more efficiently with ultrasound than larger molecules. Although investigation of large libraries of biomarkers should be performed to fully validate this hypothesis, we focus on a small subset of mRNA and micro-RNAs. Specifically, we focus on miR-21 (22 base pairs [bp]), which is upregulated in certain forms of cancer, compared with previously investigated mammaglobin mRNA (502 bp). We also report release of micro-RNA miR-155 (22 bp) and housekeeping rRNA S18 (1869 bp). More than 10 million additional miR-21 copies per 100,000 cells are released with ultrasound-microbubble exposure. The low- molecular-weight miR-21 proved to be liberated 50 times more efficiently than high-molecular-weight mammaglobin mRNA, releasing orders of magnitude more miR-21 than mammaglobin mRNA under comparable conditions.

 PubMed

Download PDF

Stay Informed

To stay up to date on all the latest news and publications, subscribe to our newsletter!

Dr. Nawaid Usmani and team receive funding for their PRIME study!

The PRIME Study – Prevention and Intervention for MEtabolic syndrome:

Androgen deprivation therapy (ADT), and newer manipulations of androgen receptor signaling have improved outcomes for advanced prostate cancer (PCa) patients.  The toxicities of ADT are many, including an increased risk of developing metabolic syndrome (MS; defined as at least 3 of: hyperglycemia; abdominal obesity; hypertriglyceridemia; reduced HDL cholesterol; and/or hypertension). MS is associated with an increased risk of diabetes, cardiovascular disease mortality, stroke mortality, and all-cause mortality.  The prevalence of MS in men receiving ADT is at least 50% and contributes to decreased quality of life and increased non-cancer-related mortality.  Metformin holds promise as a countermeasure to MS development, and also has been shown to suppress PCa growth in pre-clinical models.

We hypothesize that the addition of metformin to ADT will reduce the rates of MS in men with advanced PCa, diminishing important toxicities of a therapy universally used in advanced disease.

We propose a double-blind, randomized phase III study of metformin or placebo in men with PCa starting intermittent ADT. The primary endpoint is the difference in MS rates at 1 year.  Other aims include evaluation of the influence of metformin on: individual MS components at additional time points; mean serum insulin levels and measures of insulin resistance; weight and quality of life.

A finding that metformin reduces MS incidence and/or has other benefits would change practice, as it would provide a practical and inexpensive strategy to reduce toxicity of an intervention employed in most men with advanced PCa.

- Catalina Vasquez