Objective:To investigate the effect and molecular mechanism of circ_0001955 on the radiosensitivity of prostate cancer DU145 cells.Methods:The si-con, si-circ_0001955, miR-con and miR-149 were transfected into DU145 cells and recorded as the si-con group, si-circ_0001955 group, miR-con group, miR-149 group. The miR-149 and pc-circ_0001955 were co-transfected into DU145 cells and recorded as the miR-149+ pc-circ_0001955 group. Untreated cells were used as the blank control (NC) group. Real-time quantitative PCR was employed to detect the expression levels of circ_0001955 and miR-149. MTT assay was performed to detect cell viability. Flow cytometry was carried out to detect cell apoptosis. Transwell chamber assay was conducted to observe cell migration and invasion. Western blot was performed to detect the expression levels of MMP-2, MMP-9, Cleaved caspase-3, Cleaved caspase-9 and γ-H 2AX proteins. Colony formation assay was employed to determine the cell radiosensitivity. Dual-luciferase reporter assay was conducted to verify the targeting relationship between circ_0001955 and miR-149. Results:The circ_0001955 was highly expressed, whereas the miR-149 was lowly expressed in prostate cancer DU145 cells. Silencing circ_0001955 or over-expressing miR-149 could decrease the cell viability, migration and invasion, down-regulate the expression levels of MMP-2 and MMP-9, up-regulate the expression levels of Cleaved caspase-3 and Cleaved caspase-9, and increase the apoptosis rate (all P<0.05). After 4 Gy dose irradiation, the expression level of γ-H 2AX was up-regulated, the cell survival fraction was decreased, and the sensitivity ratio was 1.38. circ_0001955 could targetedly regulate the expression level of miR-149. After simultaneous overexpression of circ_0001955 and miR-149, cell proliferation activity and the number of migrating and invading cells were increased, cell apoptosis rate was decreased, and cell survival fraction was increased, and the sensitivity ratio was calculated as 0.72. Conclusion:Silencing circ_0001955 can targetedly up-regulate the expression level of miR-149, which inhibits the proliferation, migration, and invasion, induces cell cycle arrest, induces cell apoptosis and increases the radiosensitivity of prostate cancer DU145 cells.

Objective:To explore the feasibility and safty of robot assisted trans-diaphragmatic intropericardial inferior vena cava occlusion and thrombectomy in treatment of Ⅳa grade tumor thrombus without cardiopulmonary bypass and thoracotomy.Methods:The clinical data of 4 patients with renal cell carcinoma and Ⅳa grade tumor thrombus by robot assisted trans-diaphragmatic intropericardial inferior vena cava occlusion and thrombectomy from January 2013 to June 2019 were retrospectively analyzed. The median age was 53.5 (53-70) years. The average body mass index was 23.25 (20.7-26.3) kg/m 2. The tumors were located on the right side in 2 cases. The average maximum diameter of the tumor was 8.1 (3.6-11.2) cm.Preoperative tumor thrombus of all patients was classified as Ⅳa. The average preoperative length of tumor thrombus in vena cava was 12.3 (11.8-18.0) cm. All the operations were performed under multidisciplinary cooperation of urology, hepatobiliary, cardiovascular, ultrasound and anesthesiologist team. Surgical procedure: Robot assisted liver mobilization was used to expose the inferior vena cava. Under the guidance of intraoperative ultrasound, the central tendon and pericardium of diaphragm were dissected until the inferior vena cava and right atrium in the superior pericardium were exposed. The first porta hepatis and inferior vena cava were blocked in turn.The vena cava thrombectomy and inferior vena cava reconstruction were performed. Results:All the operations were completed without conversion. The median operation time was 553.5 (338-642) minutes, and the median time of the first porta hepatis occlusion was 18.1 (14-32)minutes. The median blood loss was 1 900(1 000-2 600)ml. All patients were transferred to ICU after operation. The median length of stay in ICU was 7(4-8) days, and the median time of indwelling drainage tube was 8(4-12) days. The average postoperative hospital stay was 13(11-20) days. There were 1 case of grade Ⅱ and 3 cases of grade Ⅲ complications (Clavien classification). One case had paroxysmal supraventricular tachycardia, one case had lymphatic fistula, one case had pleural effusion with atelectasis, and one case had hepatic and renal insufficiency and lymphatic fistula. The complications were improved after treatment. There was no perioperative death.Conclusions:Robot assisted trans-diaphragmatic intropericardial inferior vena cava occlusion and thrombectomy is an alternative method for the treatment of Ⅳa grade inferior vena cava tumor thrombus. Using this method, Ⅳa grade tumor thrombus can be treated without cardiopulmonary bypass and thoracotomy, with controllable complications and zero perioperative mortality.