Experimental Study On Biological Effect Of Sonodynamic Therapy On Ovarian Cancer Cells

Ovarian cancer is the third most common and deadliest gynecologic malignancy in the world,and most patients are diagnosed at an advanced stage due to the lack of obvious symptoms in its early stages.Drug tolerance,systemic toxicity and tumor recurrence result in a mortality rate of up to 70%in patients with advanced ovarian cancer,with an overall 5-year survival rate of only 48.8%.Therefore,it is imperative to explore new alternative treatment strategies for ovarian cancer.Sonodynamic Therapy(SDT)is an ultrasound-based treatment modality developed from Photodynamic Therapy(PDT)and has been increasingly used in recent years.Similar to PDT,SDT is now more commonly recognised as a treatment that kills tumours by producing large amounts of Reactive Oxygen Species(ROS),which activate the corresponding cancer cell death pathways.However,unlike PDT,SDT relies on the powerful penetrating power of ultrasound(>10cm)and the tumour-specific accumulation of acoustic sensitizers,making it a suitable alternative therapy for deep-seated tumours such as ovarian cancer.In this study,we used low-intensity ultrasound therapy instrument combined with Sono Vue(injectable sulfur hexafluoride microbubbles)to generate large amounts of ROS to induce apoptosis in ovarian cancer cells(SKOV3)and further investigate the anti-tumour mechanism of sonodynamic therapy.The optimal ultrasound intensity,optimal irradiation time and optimal drug concentration of ovarian cancer SKOV3 cells were firstly screened by CCK-8 assay,and cell death was detected by Calcein(green,live cells)/PI(red,dead cells)double staining;and apoptosis was detected by Annexin V-FITC/PI double staining flow cytometry.Finally,it was found that the optimal drug concentration was 12.5μg/ml,the optimal ultrasound intensity was 0.75 W/cm~2and the optimal irradiation time was 30s.Irradiation of ovarian cancer SKOV3 cells at a concentration of 12.5μg/ml and a sound intensity of 0.75 W/cm~2for 30s significantly induced the production of large amounts of reactive oxygen species and induced apoptosis in ovarian cancer SKOV3 cells.In the study of the anti-tumour mechanism of SDT,cell viability was measured by CCK-8 assay,cell migration ability by scratch assay and Transwell cell migration assay;intracellular ROS production by DCFH-DA probe,intracellular calcium ion content by Fluo-4AM probe and protein expression related to apoptosis by Western Blot.The ultrastructural changes of ovarian cancer SKOV3 cells after treatment were observed by transmission electron microscopy.Finally,RNA sequencing(RNA-Seq)was used to detect differential expression in the transcriptome,followed by enrichment and analysis of target genes and pathways associated with apoptosis using GO and KEGG pathways to search for differentially expressed genes in the ovarian cancer SKOV3 cancer cell cohort.It was found that sonodynamic therapy combined with sonovir was able to induce a high production of reactive oxygen species in ovarian cancer SKOV3 cells,causing intracellular calcium overload and consequently calcium overload-induced apoptosis.As mentioned above,this study demonstrated that sonodynamic therapy combined with sonovir can induce apoptosis in ovarian cancer SKOV3 cells,effectively inhibit proliferation and migration,and suppress tumor growth.The main mechanism is that sonodynamic therapy combined with Sonovue produce a large amounts of ROS,which induces the calcium-associated apoptotic pathway in cancer cells,thus exerting an anti-tumor effect.