Ultrasound enhanced siRNA delivery using cationic liposome-microbubble complexes for the treatment of squamous cell carcinoma.

Rationale: Microbubble (MB) contrast agents combined with ultrasound targeted microbubble cavitation (UTMC) are a promising platform for site-specific therapeutic oligonucleotide delivery. We investigated UTMC-mediated delivery of siRNA directed against epidermal growth factor receptor (EGFR), to squamous cell carcinoma (SCC) via a novel MB-liposome complex (LPX). Methods: LPXs were constructed by conjugation of cationic liposomes to the surface of C4F10 gas-filled lipid MBs using biotin/avidin chemistry, then loaded with siRNA via electrostatic interaction. Luciferase-expressing SCC-VII cells (SCC-VII-Luc) were cultured in Petri dishes. The Petri dishes were filled with media in which LPXs loaded with siRNA against firefly luciferase (Luc siRNA) were suspended. Ultrasound (US) (1 MHz, 100-µs pulse, 10% duty cycle) was delivered to the dishes for 10 sec at varying acoustic pressures and luciferase assay was performed 24 hr later. In vivo siRNA delivery was studied in SCC-VII tumor-bearing mice intravenously infused with a 0.5 mL saline suspension of EGFR siRNA LPX (7×108 LPX, ~30 µg siRNA) for 20 min during concurrent US (1 MHz, 0.5 MPa spatial peak temporal peak negative pressure, five 100-µs pulses every 1 ms; each pulse train repeated every 2 sec to allow reperfusion of LPX into the tumor). Mice were sacrificed 2 days post treatment and tumor EGFR expression was measured (Western blot). Other mice (n=23) received either EGFR siRNA-loaded LPX + UTMC or negative control (NC) siRNA-loaded LPX + UTMC on days 0 and 3, or no treatment ("sham"). Tumor volume was serially measured by high-resolution 3D US imaging. Results: Luc siRNA LPX + UTMC caused significant luciferase knockdown vs. no treatment control, p<0.05) in SCC-VII-Luc cells at acoustic pressures 0.25 MPa to 0.9 MPa, while no significant silencing effect was seen at lower pressure (0.125 MPa). In vivo, EGFR siRNA LPX + UTMC reduced tumor EGFR expression by ~30% and significantly inhibited tumor growth by day 9 (~40% decrease in tumor volume vs. NC siRNA LPX + UTMC, p<0.05). Conclusions: Luc siRNA LPXs + UTMC achieved functional delivery of Luc siRNA to SCC-VII-Luc cells in vitro. EGFR siRNA LPX + UTMC inhibited tumor growth and suppressed EGFR expression in vivo, suggesting that this platform holds promise for non-invasive, image-guided targeted delivery of therapeutic siRNA for cancer treatment.

Sign of the times: Community engagement to refine a cardiovascular mHealth intervention through a virtual focus group series during the COVID-19 Pandemic.

Background: African-Americans are underrepresented in mobile health intervention research studies which can perpetuate health inequities and the digital divide. A community-based, user-centered approach to designing mobile health interventions may increase their sociocultural relevance and effectiveness, especially with increased smartphone use during the coronavirus disease 2019 pandemic. We aimed to refine an existing mobile health intervention via a virtual focus group series. Methods: African-American community members (n = 15) from churches in Minneapolis-St. Paul and Rochester, Minnesota were enrolled in a virtual (via videoconferencing), three-session focus group series over five months to refine a cardiovascular health-focused mobile health application (FAITH! [Fostering African-American Improvement in Total Health!] App). Participants accessed the app via their smartphones and received a Fitbit synced to the app. Participants engaged with multimedia cardiovascular health-focused education modules, a sharing board for social networking, and diet/physical activity self-monitoring. Participant feedback on app features prompted iterative revisions to the FAITH! App. Primary outcomes were app usability (assessed via Health Information Technology Usability Evaluation Scale range: 0-5) and user satisfaction. Results: Participants (mean age [SD]: 56.9 [12.3] years, 86.7% female) attended a mean 2.8 focus groups (80% attended all sessions). The revised FAITH! App exceeded the goal Health Information Technology Usability Evaluation Scale score threshold of ≥4 (mean: 4.39, range: 3.20-4.95). Participants positively rated updated app content, visual appeal, and use of social incentives to maintain engagement. Increasing user control and refinement of the moderated sharing board were identified as areas for future improvement. Conclusions: Community-partnered, virtual focus groups can optimize usability and increase participant satisfaction of mobile health lifestyle interventions that aim to promote cardiovascular health in African-Americans.

Improvements in Diet and Physical Activity-Related Psychosocial Factors Among African Americans Using a Mobile Health Lifestyle Intervention to Promote Cardiovascular Health: The FAITH! (Fostering African American Improvement in Total Health) App Pilot Study.

BACKGROUND: African Americans continue to have suboptimal cardiovascular health (CVH) related to diet and physical activity (PA) behaviors compared with White people. Mobile health (mHealth) interventions are innovative platforms to improve diet and PA and have the potential to mitigate these disparities. However, these are understudied among African Americans. OBJECTIVE: This study aims to examine whether an mHealth lifestyle intervention is associated with improved diet and PA-related psychosocial factors in African Americans and whether these changes correlate with diet and PA behavioral change. METHODS: This study is a retrospective analysis evaluating changes in diet and PA-related self-regulation, social support, perceived barriers, and CVH behaviors (daily fruit and vegetable intake and moderate-intensity PA [MPA] per week) in 45 African American adults (mean age 48.7 years, SD 12.9 years; 33/45, 73% women) enrolled in the FAITH! (Fostering African American Improvement in Total Health) app pilot study. The intervention is a 10-week, behavioral theory-informed, community-based mHealth lifestyle intervention delivered through a mobile app platform. Participants engaged with 3 core FAITH! app features: multimedia education modules focused on CVH with self-assessments of CVH knowledge, self-monitoring of daily fruit and vegetable intake and PA, and a sharing board for social networking. Changes in self-reported diet and PA-related self-regulation, social support, perceived barriers, and CVH behaviors were assessed by electronic surveys collected at baseline and 28 weeks postintervention. Changes in diet and PA-related psychosocial factors from pre- to postintervention were assessed using paired 2-tailed t tests. The association of changes in diet and PA-related psychosocial variables with daily fruit and vegetable intake and MPA per week was assessed using Spearman correlation. Associations between baseline and 28-week postintervention changes in diet and PA-related psychosocial measures and CVH behaviors with covariates were assessed by multivariable linear regression. RESULTS: Participants reported improvements in 2 subscales of diet self-regulation (decrease fat and calorie intake, P=.01 and nutrition tracking, P<.001), one subscale of social support for healthy diet (friend discouragement, P=.001), perceived barriers to healthy diet (P<.001), and daily fruit and vegetable intake (P<.001). Improvements in diet self-regulation (increase fruit, vegetable, and grain intake, and nutrition tracking) and social support for healthy diet (friend encouragement) had moderate positive correlations with daily fruit and vegetable intake (r=0.46, r=0.34, and r=0.43, respectively). A moderate negative correlation was observed between perceived barriers to healthy diet and daily fruit and vegetable intake (r=-0.25). Participants reported increases in PA self-regulation (P<.001). Increase in social support subscales for PA (family and friend participation) had a moderate positive correlation with MPA per week (r=0.51 and r=0.61, respectively). CONCLUSIONS: Our findings highlight key diet and PA-related psychosocial factors to target in future mHealth lifestyle interventions aimed at promoting CVH in African Americans.

Ultrasound and Microbubble-targeted Delivery of a microRNA Inhibitor to the Heart Suppresses Cardiac Hypertrophy and Preserves Cardiac Function.

MicroRNAs (miRs) are dysregulated in pathological left ventricular hypertrophy. AntimiR inhibition of miR-23a suppressed hypertension-induced cardiac hypertrophy in preclinical models, but clinical translation is limited by a lack of cardiac-targeted delivery systems. Ultrasound-targeted microbubble cavitation (UTMC) utilizes microbubbles as nucleic acid carriers to target delivery of molecular therapeutics to the heart. The objective of this study was to evaluate the efficacy of UTMC targeted delivery of antimiR-23a to the hearts of mice for suppression of hypertension-induced cardiac hypertrophy. Methods: Cationic lipid microbubbles were loaded with 300 pmol negative control antimiR (NC) or antimiR-23a. Mice received continuous phenylephrine infusion via implanted osmotic minipumps, then UTMC treatments with intravenously injected antimiR-loaded microbubbles 0, 3, and 7 days later. At 2 weeks, hearts were harvested and miR-23a levels were measured. Left ventricular (LV) mass and function were assessed with echocardiography. Results: UTMC treatment with antimiR-23a decreased cardiac miR-23a levels by 41 ± 8% compared to UTMC + antimiR-NC controls (p < 0.01). Furthermore, LV mass after 1 week of phenylephrine treatment was 17 ± 10% lower following UTMC + antimiR-23a treatment compared to UTMC + antimiR-NC controls (p = 0.02). At 2 weeks, fractional shortening was 23% higher in the UTMC + antimiR-23a mice compared to UTMC + antimiR-NC controls (p < 0.01). Conclusions: UTMC is an effective technique for targeted functional delivery of antimiRs to the heart causing suppression of cardiac hypertrophy and preservation of systolic function. This approach could represent a revolutionary therapy for patients suffering from pathological cardiac hypertrophy and other cardiovascular conditions.