帕妥珠单抗
曲妥珠单抗
化学
内化
抗体
结合位点
表皮生长因子受体
体外
分子生物学
受体
癌症研究
生物化学
生物
癌症
医学
乳腺癌
免疫学
内科学
作者
Rohit Sharma,Manoj Kumbhakar,Archana Mukherjee
标识
DOI:10.1021/acs.molpharmaceut.1c00775
摘要
Human epidermal growth factor receptor 2 (HER2) is overexpressed in breast, gastric, esophageal, ovarian, and endometrial cancer. Combination therapy using trastuzumab and pertuzumab antibodies targeting HER2 has shown better survival outcomes in breast cancer patients. In the quest to understand the synergistic effect observed due to combination therapy, trastuzumab, pertuzumab, and their F(ab')2 fragments were labeled with radioisotope and fluorescent probes. Detailed in vitro studies to understand binding synergism in HER2 overexpressing cell lines were done. Antibodies and their F(ab')2 fragments prepared by enzyme digestion with pepsin were radiolabeled with iodine-125. In vitro binding studies to evaluate immunoreactivity, specificity, affinity, and binding synergism between radiolabeled trastuzumab, pertuzumab, and their F(ab')2 fragments were carried out. Synergism was observed by 20-30% enhanced uptake of radiolabeled pertuzumab and its F(ab')2 fragments in the presence of excess of unlabeled trastuzumab or F(ab')2-trastuzumab. However, uptake of radiolabeled trastuzumab was not enhanced in the presence of excess pertuzumab or its fragments; rather inhibition or competition in binding to HER2 was observed. Studies using fluorescent antibodies by flow cytometry confirmed enhanced binding of pertuzumab in the presence of trastuzumab. Live cell tracking was done to give insights into the binding synergy and fate of fluorescent antibodies . Colocalization of antibodies on HER2 followed by internalization in the cells was observed. The radiolabeled immunoconjugates served as an important tool for experimental characterization of interaction between pertuzumab and trastuzumab to HER2. Studies with fluorescent antibodies corroborated the binding data and provided evidence of colocalization and internalization of both the antibodies in HER2-positive cells.
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