Diagnosis of prostate cancer using anti-PSMA aptamer A10-3.2-oriented lipid nanobubbles

Abstract

In this study, the lipid targeted nanobubble carrying the A10-3.2 aptamer against prostate specific membrane antigen was fabricated, and its effect in the ultrasound imaging of prostate cancer was investigated. Materials including 2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dipalmitoyl-sn-glycero-3-phosphatidic acid, 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine, 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol, carboxyl-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine, and polyethyleneglycol-2000 were for mechanical oscillation, and nanobubbles were obtained through the centrifugal flotation method. After mice were injected with nanobubbles, abdominal color Doppler blood flow imaging significantly improved. Through left ventricular perfusion with normal saline to empty the circulating nanobubbles, nanobubbles still existed in tumor tissue sections, which demonstrated that nanobubbles could enter tissue spaces via the permeability and retention effect. Fluorinated A10-3.2 aptamers obtained by chemical synthesis had good specificity for PSMA-positive cells, and were linked with carboxyl-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine lipid molecules from the outer shell of nanobubbles via amide reaction to construct targeted nanobubbles. Gel electrophoresis and immunofluorescence confirmed that targeted nanobubbles were fabricated successfully. Next, targeted nanobubbles could bind with PSMA-positive cells (C4-2 cells), while not with PSMA-negative cells (PC-3 cells), using in vitro binding experiments and flow cytometry at the cellular level. Finally, C4-2 and PC-3 xenografts in mice were used to observe changes in parameters of targeted and non-targeted nanobubbles in the contrast-enhanced ultrasound mode, and the distribution of Cy5.5-labeled targeted nanobubbles in fluorescent imaging of live small animals. Comparison of ultrasound indicators between targeted and non-targeted nanobubbles in C4-2 xenografts showed that they had similar peak times ( P >0.05), while the peak intensity, half time of peak intensity, and area under the curve of ½ peak intensity were significantly different ( P <0.05). In PC-3 xenografts, there were no differences in these four indicators. Fluorescent imaging indicated that targeted nanobubbles had an aggregation ability in C4-2 xenograft tumors. In conclusion, targeted nanobubbles carrying the anti-PSMA A10-3.2 aptamer have a targeted imaging effect in prostate cancer.

Optimized Anti–Prostate‐Specific Membrane Antigen Single‐Chain Variable Fragment–Loaded Nanobubbles as a Novel Targeted Ultrasound Contrast Agent for the Diagnosis of Prostate Cancer

“…4 Therefore, NBs have become a popular topic of recent research on targeted CEUS. Their size of less than 700 nm is advantageous for targeted NBs to reach tumor targets by passing through the vascular endothelium of small, defective tumor blood vessels, 10,11,33 and in vivo, NBs provide a longer period of enhancement for imaging than MBs. 8,9 Furthermore, NBs have the advantage of prolonged blood circulation due to their small size and high stability.…”

“…Targeted NBs are prepared by loading a specific ligand onto the surface of the NBs, which can then circulate through the blood and pass through the vascular endothelium to reach the target tissue; here, the NBs can aggregate and persist for a long time. Studies have shown that targeted NBs can increase the peak time and intensity values of tumor imaging in vitro compared to nontargeted NBs . Prostate‐specific membrane antigen (PSMA), which was discovered in 1987, is a unique intact transmembrane type 2 glycoprotein in prostate epithelial cells .…”

“…Studies have shown that targeted NBs can increase the peak time and intensity values of tumor imaging in vitro compared to nontargeted NBs. [10][11][12] Prostate-specific membrane antigen (PSMA), which was discovered in 1987, is a unique intact transmembrane type 2 glycoprotein in prostate epithelial cells. 13 Its expression is positively correlated with the mortality rate of PCa 14 and is considered the most important protein target in diagnostic-specific immunolocalized imaging and immunoguided therapy.…”

PSMA-Targeting Redox Hyperbranched Poly (Amido Amine)-Mediated miR-133a-3p Delivery to Inhibit Bone Metastasis of Prostate Cancer

“…The A 10 − 3.2 aptamer (APT) has only 39 nucleotides, its weight is signi cantly reduced and it has good binding a nity to PSMA. Thus, many research teams have focused on APT-targeting gene delivery and favorable effects were reported [11,[24][25][26] .…”

Paclitaxel-loaded and A10-3.2 aptamer-targeted poly(lactide-<em>co</em>-glycolic acid) nanobubbles for ultrasound imaging and therapy of prostate cancer

“…[25][26][27] We also selected an A10-3.2 aptamer having merely 39 nucleotides as the targeting agent, which likely binds the intended proteins using optimal specificity and similarity, thus modulating the function of the target protein. [28][29][30] Aptamers, with stable structures and little immunogenicity, 31 can be chemically synthesized and stabilized. A10-3.2 aptamers conjugated to NBs increase targeting, resulting in more efficient therapeutics and more selective diagnostics.…”