Dual-targeted and pH-sensitive Doxorubicin Prodrug-Microbubble Complex with Ultrasound for Tumor Treatment

Abstract

In this study, we investigated the potential of a dual-targeted pH-sensitive doxorubicin prodrug-microbubble complex (DPMC) in ultrasound (US)-assisted antitumor therapy. The doxorubicin prodrug (DP) consists of a succinylated-heparin carrier conjugated with doxorubicin (DOX) via hydrazone linkage and decorated with dual targeting ligands, folate and cRGD peptide. Combination of microbubble (MB) and DP, generated via avidin-biotin binding, promoted intracellular accumulation and improved therapeutic efficiency assisted by US cavitation and sonoporation. Aggregates of prepared DP were observed with an inhomogeneous size distribution (average diameters: 149.6±29.8 nm and 1036.2±38.8 nm, PDI: 1.0) while DPMC exhibited a uniform distribution (average diameter: 5.804±2.1 μm), facilitating its usage for drug delivery. Notably, upon US exposure, DPMC was disrupted and aggregated DP dispersed into homogeneous small-sized nanoparticles (average diameter: 128.6±42.3 nm, PDI: 0.21). DPMC could target to angiogenic endothelial cells in tumor region via αvβ3-mediated recognition and subsequently facilitate its specific binding to tumor cells mediated via recognition of folate receptor (FR) after US exposure. In vitro experiments showed higher tumor specificity and killing ability of DPMC with US than free DOX and DP for breast cancer MCF-7 cells. Furthermore, significant accumulation and specificity for tumor tissues of DPMC with US were detected using in vivo fluorescence and ultrasound molecular imaging, indicating its potential to integrate tumor imaging and therapy. In particular, through inducing apoptosis, inhibiting cell proliferation and antagonizing angiogenesis, DPMC with US produced higher tumor inhibition rates than DOX or DPMC without US in MCF-7 xenograft tumor-bearing mice while inducing no obvious body weight loss. Our strategy provides an effective platform for the delivery of large-sized or aggregated particles to tumor sites, thereby extending their therapeutic applications in vivo.

Induction of enhanced immunogenic cell death through ultrasound-controlled release of doxorubicin by liposome-microbubble complexes

“…[7][8][9][10][11][12] The ultrasound (US)-controlled release of chemotherapeutics by microbubbles (MBs) has become a promising therapeutic approach for drug delivery to treat malignant tumors. [16][17][18][19][20][21] In this strategy, chemotherapeutics are incorporated into MB shells by hydrophobic interactions, or attached to MB shells by various approaches, such as nanoparticles. [20][21][22][23][24] Thereafter, the MB-loaded chemotherapeutics are then released from MBs that flow through the targeted tumor tissues by high-intensity focused US.…”

“…[16][17][18][19][20][21] Although liposome-microbubble complexes have improved the targeted tumor delivery and accumulation of chemotherapeutic drugs, the role of ICD in this process has not been elucidated. [16][17][18][19][20][21] In this study, we constructed a liposome-MB complex in which doxorubicin (Dox, an ICD inducer) was encapsulated in a liposome (Dox-liposome) and attached to the lipid shell of MBs via avidin-biotin linkage. Thereafter, we detected the efficacy of US-triggered drug delivery from these complexes in LL/ 2c and CT26 tumor models, and focused on the comparative effects of the respective drug preparations as well as the levels of ICD that they provoked.…”

<p>New Aspects of Ultrasound-Mediated Targeted Delivery and Therapy for Cancer</p>

“…The results showed that the anti-tumor efficacy of resveratrol on tumor-bearing mice was significantly enhanced. With ultrasound coordination, Luo et al 43 devised pH-sensitivemicrobubble complex, which consists of a succinylatedheparin carrier combined with Dox through hydrazone linkage and conjugated with dual targeting ligands through biotin-avidin binding ( Figure 4A). In particular, the pHsensitive nanoparticles attained high tumor inhibition rates in the experiment of inhibiting cell proliferation, inducing apoptosis and anti-tumor angiogenesis, providing an effective strategy for targeting drug delivery and ultrasound imaging ( Figure 4B and C).…”

<p>Targeted Therapy for Hepatocellular Carcinoma: Co-Delivery of Sorafenib and Curcumin Using Lactosylated pH-Responsive Nanoparticles</p>

“…The release manners of SFN and CCM from LAC-SFN /CCM-NPs, LAC-SFN-NPs, LAC-CCM-NPs, and SFN/ CCM-NPs were examined using dialysis method. 38 Briefly, samples were dissolved in phosphate-buffered saline solution (PBS, 5 mL, pH 5.5 or 7.4) and sealed separately in dialysis bags. Samples were dialyzed against 50 mL corresponding buffers, which were incubated in a 37°C water bath under constant shaking (100 rpm).…”