AG825对乳腺癌细胞的辐射增敏作用

目的:通过体外实验观察酪氨酸蛋白激酶抑制剂AG825对人类表皮生长因子受体2(ERBB-2)高表达乳腺癌细胞的生长抑制作用和辐射增敏作用,并从DNA双链断裂(Double strand break,DSB)损伤修复的角度初步探讨AG825辐射增敏机制。方法:首先通过MTT比色法观察了不同浓度AG825对ERBB-2高表达乳腺癌细胞系MDA-MB-453生长抑制作用。然后将细胞设为空白对照组,单纯放射组,AG825预处理组。通过克隆形成实验观察AG825预处理组和单纯辐射组乳腺癌细胞辐射后生存分数(Survivial fraction,SF)的差异。并且通过单细胞中性凝胶电泳分析了AG825预处理对辐射诱导的DSB的影响。同时用免疫印记法分析AG825预处理后MDA-MB-453细胞在辐射后不同时间DSB修复的关键激酶DNA依赖蛋白激酶催化亚单位(DNA dependent protein kinase catalytic sub-unit,DNA-PKcs)蛋白的表达情况。结果:MTT比色法显示AG825对MDA-MB-453生长抑制作用随AG825浓度增高而增加。辐射后单纯放射组MDA-MB-453细胞生存分数较空白对照组明显下降。AG825预处理组辐射后生存分数较单纯放射组进一步下降,同时DSB较单纯放射组增加。免疫印记显示单纯放射组DNA-PKcs蛋白表达在辐射后较空白对照组增加,而AG825预处理组DNA-PKcs表达较单纯放射组下降。结论:AG825对ERBB2高表达乳腺癌细胞具有生长抑制作用。并且其对ERBB2高表达乳腺癌细胞具有辐射增敏作用,其辐射增敏机制可能与AG825抑制DNA-PKcs蛋白表达而减少辐射后DSB修复有关。但还需进一步的体内实验来评价AG825辐射增敏作用。

Preliminary results of acoustic radiation force impulses (ARFI) ultrasound imaging of solid suspicious breast lesions

Objective： The aim of our study was to make the qualitative and quantitative analysis to breast lesions using acoustic radiation force impulses （ARFI）, and assess the diagnostic value of ARFI for differentiation between benign and malignant solid breast masses, meanwhile evaluate the influences of ARFI with breast imaging reporting and data system （BI-RADS） of suspicious masses. Methods： Seventy-five women with 86 breast lesions underwent conventional breast ultra- sound examination. Then B-mode BI-RADS features and assessments were recorded and standard breast US supplemented by ARFI elastographic examination were repeated. The data were recorded and analyzed as following： area ratio of breast lesion, the shear-wave velocity, the ratio of the shear-wave velocity between lesions and surrounding normal tissues, and according to the elastographic data reconsidered the BI-RADS category, all the results have been correlated with pathological results and make statistical evaluations of ARFI for differentiation between benign and malignant solid breast masses. Meantime our study has correlated the adjusted BI-RADS category of suspicious breast lesions with the pathological results and made assessment. Results： Thirty-eight patients were malignant breast carcinoma （31 invasive ductal carcinoma, 5 intraductal carcinoma in situ, 2 medullary carcinoma, 2 invasive Iobular carcinoma）, 48 patients were benign breast lesions （23 fibroadenoma, 12 benign nodular hyperplasia, 5 phyllodes tumor, 6 adenosis, 2 intraductal papilloma）. Underwent conventional breast ultrasound exam, 42 cases were BI-RADS category 3, 23 cases were BI-RADS category 4. When adding elastographic data, 46 cases were BI-RADS category 3 and 20 cases were BI-RADS category 4. Compared with pathological results showed for both the specificity of BIRADS features and the area under ROC curve has risen. Virtual touch tissue imaging （VTI） and virtual touch tissue quantification （VTQ） data showed the area ratio （AR） between elastographic lesions area and B-mode lesions area, SWV （maximal shear-wave velocity of lesions）, R-SWV （shear-wave velocity ratio between lesions and surrounding normal tissues） in benign breast lesions were lower than those in malignant lesions which has statistical significance and the cut-off point were 1.1,4.65 m/s, 5.18 respectively. Conclusion： The ARFI elastography can provide the reliable qualitative and quantitative analysis about hardness of breast lesions, supply the new BI-RADS category features to suspicious breast masses and serve as an effective diagnostic tool for differentiation between benign and malignant solid masses.

AG825 increases radiosensitivity of breast cancer cell

Objective:To observe the radiosensitivity effect of AG825 on breast cancer cell line with high expression of ERBB2 in vitro.Methods:MTT and clone formation assay were used to observe the effect of AG825 on proliferation and radiosensitivity of breast cancer line MDA-MB-453.After MDA-MB-453 was exposed to AG825 and radiation,comet assay and Western blotting were applied to detect double strand break and expressions DNA-PKcs protein,respectively.Results:AG825 inhibited proliferation rate and decrease survival fraction of MDA-MB-453.After radiation,compared with control group,expression of DNA-PKcs was lower in group with AG825 presence but double strand break was higher.Conclusion:AG825 could increase radiosensitivity of breast cancer cell line MDA-MB-453,and it may associate with its inhibition of radiation induced expression of DNA-PKcs and double strand break repair.