Targeted DTX-Loaded Liposome Microbubbles For Therapy Of Prostate Cancer

Prostate cancer is one of the most common malignancy in older men.Early prostate cancer can be treated by surgery and multiple endocrine combined therapy, but as the disease progresses, most prostate cancer gradually changed from hormone-dependent to hormone-insensitive, and eventually become hormone-resistant.Endocrine herapy has failed this time, the cancer only be converted using the treatment docetaxel-based chemotherapy dominated. But because of the lack of targeting of tumor and normal tissue and greater systemic side effects of docetaxel drugs, prostate cancer patients are elderly patients and too poor tolerance to adhere to the course of treatment. Targeted drug-loaded microbubbles combining with ultrasound has become a new method of non-invasive cancer drug delivery mode in recent years. Targeted drug-loaded microbubbles can bind to tumor tissue by virtue of its initiative homing function after intravenous injection following the blood circulation. Tumor surface is exposured by ultrasonic irradiation and the fracture of microbubbles form cavitation, which causes the drug released from the microbubbles into the tumor tissue.Meantime the powerful sound energy produced by cavitation can destroy the tumor cell membrane integrity, resulting in a reversible or irreversible tiny sound hole, accelerating extracellular drug enters to the interior of the cell through the sound hole, achieving a drug targeted positioning release. Therefore, this study is to desire a targeted DTX-loaded liposome microbubbles(DLMB) encapsulating with perfluoropropane(C3F8) using prostate-specific membrane antigen(PSMA) as a target and explore the therapy of terminal-stage prostate cancer bycombination of ultrasound and targeted DLMB.DPPE-PEG-APP as the most important part of targeted DLMBs was synthesized by coupling diblock copolymer(DPPE-PEG-NH2) with anti-prostate-specific membrane antigen polypeptide (Anti-PSMA polypeptide)by condensation reaction between amino and carboxyl groups. DLMBs encapsulating with C3F8 were prepared by a thin-film hydration-sonication and acoustic vibration method,the morphology and distribution were observed with optical microscope. The prepared DLMBs that can remain stabilization at 4℃ at least 3 days were opacified suspension in appearance, the distribution and size were uniformed with core-shell structure, with the average size and Zeta potentials of (1.38±0.21) μm,(-27.5±3.76) mV respectively. The encapsulation efficiency anddrug loading efficiency were (84.48±1.07)% and (6.79±0.93)%respectively. In vitro release experiments show DLMBs can be stable presence in a simulated environment, the drug slowly leaking.In order to verify the performance of the targeted and antitumor efficiency of DLMB ultrasound combined with, conduct follow-cell adhesion, cytotoxicity, cell uptake experiments and other experiments. Experimental results show that targeted microbubble have the ability to identify specific to expression of PSMA LnCap cells, while not expressing PSMA in PC-3 cells do not. After ultrasound irradiation, the cells will be more uptake of the drug package, effectively reducing the IC50 value of docetaxel.To further verify the preparation of microbubbles in vivo anti-tumor efficiency, build cells subcutaneously in nude mice LnCap late xenograft model. Nude mice treated by PBS, free DTX, untarget DLMBs+US, targeted DLMBs, targeted DLMBs+US respectively, the ultrasonic irradiation followed after 30 min.administered once every other 5 days continuous treatment for 30 days. In vitro experiments showed, targeted DLMBs+US group has the most obvious effects on cancer therapy, tumor volume comparing to the PBS group(2.89± 0.24) cm3 free DTX group tumor volume (2.32±0.16) cm3, its tumor volume of (0.93± 0.08) cm3. Microbubbles and ultrasonic irradiation can inhibit tumor growth, histopathology and apoptosis analysis showed that the drug-loaded nanoparticles can more effectively induce apoptosis of tumor cells. Its conduct safety studies showed that the drug-loaded nanoparticles without significant organ toxicity.