Study Of Sono/Immuno-therapy Mediated By Novel Chlorin Derivative DYSP-C34 For Cancer Treatment

Sonodynamic therapy(SDT),developed on the basis of photodynamic therapy(PDT),is a new type of cancer treatment based on the synergistic effect of ultrasound and sonosensitizers.By taking advantages of its high tissue-penetrating capability,good specificity,as well as few side effects,SDT has gradually attracted wide attention and has become one of the most promising non-invasive methods for the treatment of malignant tumors.But so far,there are still many problems to be resolved before the clinical application of SDT.Therefore,with the ultimate goal of promoting the development and clinical utility of SDT,following research work was carried out based on sonodynamic device and sonosensitizers.For uniform"standardized"setups of ultrasound equipment,herein,a cell or animal sonodynamic device based on free-field ultrasound was constructed.Compared with standing wave ultrasound,the free-field ultrasound had stable ultrasound pressure output under different intensities(0.91,1.88,3.21 W/cm~2)and less damage to cell membrane.The acoustic pressure threshold of ultrasonic cavitation(0.107-0.117 MPa)was determined by monitoring the production of reactive oxygen species in the sonosensitizer solution.Furthermore,the long-term growth inhibition of tumor cells was realized under free-field ultrasonic condition with the established method for in vitro sonodynamic activity evaluation,which provided a scientific and effective research platform for the screening and application of sonosensitizers.In order to develop a sonosensitizer for clinical application,a light/ultrasound-triggered"molecular machine"3~2-(4-methoxyphenyl)-15~2-aspartyl-chlorin(DYSP-C34)was synthesized by amphiphilic chemical modification of chlorins with regioselective substitution of lipophilic and hydrophilic groups.In addition,this strategic chemical modification not only enhanced the intracellular uptake and sono/photo-damage ability of DYSP-C34,but also endowed DYSP-C34 with rapid(within 1 h)tumor targeting and accumulation.Thus,the excellent photodynamic antitumor effect mediated by DYSP-C34 was realized after irradiation with low-fluence(6 J/cm~2)light.Driven by free-field ultrasound,DYSP-C34 could effectively inhibit the tumors in situ of the mouse breast cancer,induce immunogenic cell death,promote tumor antigen presentation,and cause a specific immune response,sequentially preventing tumor metastasis.In addition,the intrinsic immune-boosting ability of DYSP-C34 potentiated adaptive anti-tumor immunity by directly stimulating dendritic cells(DCs),resulting in synergistically enhanced anti-tumor activity.With the immune-boosting effects triggered by ultrasound,the antitumor effect of DYSP-C34-mediated SDT was further corroborated by decreasing the aggressive liver metastasis and inducing long-lasting immune memory in a murine colorectal cancer model.Based on the above,we proposed the novel concept of"unimolecule-mediated sono/immuno-therapy".Our research indicates that the potent muti-functional“molecular machine”,DYSP-C34,with tumor targeting capacity,ultrasound-activable cytotoxicity and intrinsic immune-boosting effect,could be driven by free-field ultrasound and fight against tumor development and invasion systematically via an unimolecule-mediated sono-immuno synergistic therapy.