Objectives Multi-drug resistance (MDR) to chemotherapy is the main obstacle influencing the anti-tumor effect in breast cancer, which might lead to the metastasis and recurrence of cancer. Until now, there are still no effective methods that can overcome MDR. In this study, we aimed to investigate the role of sphingomyelin synthase 2 (SMS2) in breast cancer resistance. Methods Quantitative RT-PCR analysis was performed to assess changes in mRNA expression. Western blot analysis was performed to detect protein expression. Inhibitory concentration value of adriamycin (ADR) was evaluated using CCK 8 assay. The stemness ability of breast cancer cells was assessed by spheroid-formation assay. Immunofluorescence staining was conducted to show the cellular distribution of proteins. Breast tumor masses were harvested from the xenograft tumor mouse model. Results SMS2 overexpression increased the IC50 values of breast cancer cells. SMS2 decreased the CD24 transcription level but increased the transcription levels of stemness-related genes including CD44, ALDH, OCT 4 and SOX2 in breast cancer cells. SMS2 overexpression promoted the nuclear translocation of phosphorylated NF-κB, while suppression of SMS2 could inhibit the NF-κB pathway. Conclusions SMS2 increased the stemness of breast cancer cells via NF-κB signaling pathway, leading to resistance to the chemotherapeutic drug ADR. Thus, SMS2 might play a critical role in the development of breast cancer resistance, which is a previously unrecognized mechanism in breast cancer MDR development.

目的:探讨神经鞘磷脂合成酶2(SMS2)的表达与阿霉素(ADR)致乳腺癌细胞线粒体损伤的相关性.方法:采用过表达慢病毒感染法构建并筛选SMS2过表达的乳腺癌MCF-7细胞.CCK-8实验检测细胞对ADR的IC50值,选择适当浓度的ADR药物作用条件处理细胞后,使用MitoSOX试剂染色检测线粒体ROS水平,检测细胞内ATP水平以评估线粒体功能;电镜观察线粒体超微结构的异同;Western blot检测线粒体细胞色素C的释放水平和细胞凋亡相关蛋白Cleaved-PARP、Cleaved-Caspase 3、Bcl-2、Bax表达水平.结果:SMS2过表达的MCF-7细胞对ADR的IC50值为(2.42±0.073)μmol/L,而对照组细胞IC50值为(0.62±0.036)μmol/L(P<0.01).2μmol/L ADR处理细胞24 h后,SMS2过表达的MCF-7细胞内线粒体ROS水平降低(P<0.05);细胞内ATP水平增加(P<0.05);电镜观察示线粒体结构性损伤减轻;线粒体细胞色素C的释放水平降低(P<0.05);抗凋亡蛋白Bcl-2表达增加,促凋亡蛋白Cleaved-PARP、Cleaved-Caspase 3、Bax的表达减少(P<0.05).结论:SMS2过表达可能通过减轻ADR对乳腺癌MCF-7细胞线粒体的损伤作用,进而抑制细胞凋亡.

Background The E75 and GP2 vaccines are the few therapeutic vaccines targeting HER2 currently under clinical research for patients with breast cancer. Methods Databases, including the Cochrane Library, PubMed, Medline, Embase, and Web of Science, were used to retrieve clinical studies on E75 and GP2 vaccines. Retrieval time was from the beginning of database construction until May 31st, 2021. Results A total of 24 clinical studies were included in this analysis, including 1704 patients in the vaccinated group and 1248 patients in the control group. For the E75 vaccine, there were significant differences between the vaccinated group and the control group in the delayed-type hypersensitivity reaction (SMD = 0.685 95% CI 0.52–0.85, P Heterogeneity = 0.186, P DTH < 0.05) and the change in CD8 + T-cell numbers (SMD = − 0.864, 95% CI − 1.02 to − 0.709, P Heterogeneity = 0.085, P CD8+ T cell < 0.05) before and after injection. For the GP2 vaccine, there was a significant difference between the vaccinated group and the control group in the change in CD8 + T-cell numbers (SMD = − 0.584, 95% CI − 0.803 to − 0.294, P Heterogeneity = 0.397, P CD8+ T cell < 0.05) before and after injection. In addition, the clinical outcomes, including recurrence rate (RR = 0.568, 95% CI 0.444–0.727, P Heterogeneity = 0.955, P Recurrence < 0.05) and disease-free survival rate (RR = 1.149, 95% CI 1.050–1.256, P Heterogeneity = 0.003, P DFS < 0.05), of the E75-vaccinated group were different from those of the control group. However, we found that the overall survival rate with the E75 vaccine (RR = 1.032, 95% CI 0.998–1.067, P Heterogeneity = 0.476, P OS > 0.05) was not different between the two groups. Local and systemic toxicity assessments of the two vaccines showed minimal side effects. Conclusions The E75 vaccine was effective and safe in patients with breast cancer. The GP2 vaccine could elicit a strong immune response, but more trials are needed to confirm its clinical efficacy.

机械灌注(MP)技术是器官移植领域的全球研究热点之一,近年的探索成果显示出其在器官保存、器官活力评估、修复受损器官中的优异性,将引领器官捐献与移植模式的变革.本文就近期MP技术在提升器官保存效果、评估器官活力、修复器官以及进行干预性治疗等方面的研究进展进行综述,并讨论未来临床应用的潜在模式.