Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Technol Cancer Res Treat. 2013 Feb;12(1):53-60. doi: 10.7785/tcrt.2012.500253. Epub 2012 Aug 10.
Blood vessels within tumours represent a key component for cancer cell survival. Disruption of these vessels can be achieved by inducing vascular endothelial-cell apoptosis. Moreover, endothelial cell apoptosis has been proven to be enhanced by ceramide-increasing drugs. Herein, we introduce a novel therapeutic approach which uses ultrasound-stimulated microbubbles used in combination with radiation to cause a rapid accumulation of ceramide in endothelial cells in-vitro. We also test this modality directly with other cell types as a general method of killing cancer cells. Human umbilical vein endothelial cells (HUVEC), acute myeloid leukemia cells (AML), murine fibrosarcoma cells (KHT-C), prostate cancer cells (PC3), breast cancer cells (MDA-MB-231) and astrocytes were used to evaluate this mechanism of inducing cell death. Survival was measured by clonogenic assays, and ceramide content was detected using immunohistochemistry. Exposure of cell types to ultrasound-stimulated bubbles alone resulted in increases in ceramide for all cell types and survivals of 12 ± 2%, 65 ± 5%, 83 ± 2%, 58 ± 4%, 58 ± 3%, 18 ± 7% for HUVEC, AML, PC3, MDA, KHT-C and astrocyte cells, respectively. Results from selected cell types involving radiation treatments indicated additive treatment enhancements and increases in intracellular ceramide content one hour after exposure to ultrasound-activated microbubbles and radiation. Endothelial cell survival decreased from 8 ± 1% after 2 Gy of radiation treatment alone and from 12 ± 2% after ultrasound and microbubbles alone, to 1 ± 1% with combined treatment. In Asmase +/+ astrocytes, survival decreased from 56 ± 2% after 2 Gy radiation alone and from 17 ± 7% after ultrasound and microbubbles alone, to 5 ± 2% when combined. Using ASMase deficient astrocytes (Asmase -/- ) and Sphingosine-1-phosphate (S1P), we also demonstrate that ultrasound-activated microbubbles stimulate ASMase activity and ceramide production. These findings suggest that ultrasound-stimulated microbubbles could be used as a new biomechanical method to enhance the effects of radiation.
肿瘤内的血管是癌细胞存活的关键组成部分。通过诱导血管内皮细胞凋亡可以破坏这些血管。此外,已经证明神经酰胺增加药物可以增强内皮细胞凋亡。在此,我们介绍了一种新的治疗方法,该方法使用超声刺激微泡与辐射结合,在体外使内皮细胞中神经酰胺快速积累。我们还直接使用其他细胞类型作为杀死癌细胞的一般方法来测试这种模式。人脐静脉内皮细胞(HUVEC)、急性髓性白血病细胞(AML)、鼠纤维肉瘤细胞(KHT-C)、前列腺癌细胞(PC3)、乳腺癌细胞(MDA-MB-231)和星形胶质细胞用于评估这种诱导细胞死亡的机制。通过集落形成测定法测量存活率,并用免疫组织化学法检测神经酰胺含量。单独暴露于超声刺激的微泡会导致所有细胞类型的神经酰胺增加,HUVEC、AML、PC3、MDA、KHT-C 和星形胶质细胞的存活率分别为 12 ± 2%、65 ± 5%、83 ± 2%、58 ± 4%、58 ± 3%、18 ± 7%。涉及辐射处理的选定细胞类型的结果表明,在暴露于超声激活的微泡和辐射后一小时,联合治疗增强了治疗效果并增加了细胞内神经酰胺含量。单独进行 2 Gy 辐射处理后,内皮细胞存活率从 8 ± 1%下降至 12 ± 2%,单独进行超声和微泡处理后,存活率从 12 ± 2%下降至 1 ± 1%,联合处理后存活率进一步下降至 1 ± 1%。在 Asmase +/+ 星形胶质细胞中,单独进行 2 Gy 辐射处理后存活率从 56 ± 2%下降至 17 ± 7%,单独进行超声和微泡处理后存活率从 17 ± 7%下降至 5 ± 2%,联合处理后存活率进一步下降至 5 ± 2%。使用 ASMase 缺陷型星形胶质细胞(Asmase -/-)和鞘氨醇-1-磷酸(S1P),我们还证明超声激活的微泡可刺激 ASMase 活性和神经酰胺的产生。这些发现表明,超声刺激的微泡可作为一种新的生物力学方法来增强辐射的效果。