Since trastuzumab monotherapy for treatment of breast cancer with HER2/ErbB2 over-expression has been shown to have limited efficacy, combined treatment of trastuzumab with chemotherapy is widely practiced in clinic. ...Since trastuzumab monotherapy for treatment of breast cancer with HER2/ErbB2 over-expression has been shown to have limited efficacy, combined treatment of trastuzumab with chemotherapy is widely practiced in clinic. However, certain combination treatments of trastuzumab and chemotherapy (i.e. doxorubicin) are not recommended due to high risk of cardiotoxicity. Antibody-drug conjugates (ADCs) offer selective delivery of cytotoxic agents into targeted cancer cells, thereby allowing for reduced general cellular cytotoxicity caused by chemotherapeutic agents through antibody mediated specific recognition of tumor antigens. In this study, we constructed a trastuzumab-doxorubicin conjugate (T-Dox) using a thioether linkage and characterized both biophysical stability and anti-cancer potency of the T-Dox using a panel of HER2 expressing cancer cell lines. The T-Dox conjugate showed significantly improved anti-cancer potency in comparison with trastuzumab. The results demonstrated for the first time that there were significant differences in the uptake of T-Dox among high HER2 expression cancer cells and higher T-Dox uptake also showed stronger anti-cancer potency. Similar to trastuzumab, T-Dox selectively bound to HER2 overexpressing cancer cells and low HER2 expression cells had no detectable uptake of T-Dox. Consistent to the uptake data, human cardiomyocyte cells had no detectable HER2 expression and T-Dox showed minimal cytotoxic effects. On the contrary, a treatment with combination of trastuzumab and doxorubicin showed severe cytotoxicity to human cardiomyocytes (>90% cell death after 3 day exposure). This study demonstrated that trastuzumab conjugated with doxorubicin (T-Dox) can provide valuable alternative to the combination treatment with doxorubicin and trastuzumab for high HER2 expressing cancer patients.展开更多
Once thrombi have formed as part of the pathology defining myocardial infarction, ischemic stroke, peripheral arterial disease, deep venous thrombosis or other embolic disorders, the only clinically meaningful thrombo...Once thrombi have formed as part of the pathology defining myocardial infarction, ischemic stroke, peripheral arterial disease, deep venous thrombosis or other embolic disorders, the only clinically meaningful thrombolytic agents available for reversing the thrombogenic process are various plasminogen activators. These agents are enzymes that reverse fibrin polymerization underlying the coagulation process by converting endogenous plasminogen to plasmin, which cleaves the fibrin network to form increasingly smaller protein fragments, a process known as fibrinolysis. For the most part, the major clinically used thrombolytics, tissue plasminogen activator, urokinase and streptokinase, as well as the experimentally investigated agent staphylokinase, are the products of recombinant DNA technology, which permits molecular optimization of clinical efficacy. In all cases of molecular optimization and targeting, however, the primary challenge of thrombolytic therapy remains hemorrhagic side effects, which are especially devastating when they occur intracerebrally. Currently, the best strategy to ameliorate this adverse effect is nanoparticulate encapsulation or complexation, and many strategies of this sort are being actively pursued. This review summarizes the variety of targeted and untargeted thrombolytic formulations that have been investigated in preclinical studies.展开更多
文摘Since trastuzumab monotherapy for treatment of breast cancer with HER2/ErbB2 over-expression has been shown to have limited efficacy, combined treatment of trastuzumab with chemotherapy is widely practiced in clinic. However, certain combination treatments of trastuzumab and chemotherapy (i.e. doxorubicin) are not recommended due to high risk of cardiotoxicity. Antibody-drug conjugates (ADCs) offer selective delivery of cytotoxic agents into targeted cancer cells, thereby allowing for reduced general cellular cytotoxicity caused by chemotherapeutic agents through antibody mediated specific recognition of tumor antigens. In this study, we constructed a trastuzumab-doxorubicin conjugate (T-Dox) using a thioether linkage and characterized both biophysical stability and anti-cancer potency of the T-Dox using a panel of HER2 expressing cancer cell lines. The T-Dox conjugate showed significantly improved anti-cancer potency in comparison with trastuzumab. The results demonstrated for the first time that there were significant differences in the uptake of T-Dox among high HER2 expression cancer cells and higher T-Dox uptake also showed stronger anti-cancer potency. Similar to trastuzumab, T-Dox selectively bound to HER2 overexpressing cancer cells and low HER2 expression cells had no detectable uptake of T-Dox. Consistent to the uptake data, human cardiomyocyte cells had no detectable HER2 expression and T-Dox showed minimal cytotoxic effects. On the contrary, a treatment with combination of trastuzumab and doxorubicin showed severe cytotoxicity to human cardiomyocytes (>90% cell death after 3 day exposure). This study demonstrated that trastuzumab conjugated with doxorubicin (T-Dox) can provide valuable alternative to the combination treatment with doxorubicin and trastuzumab for high HER2 expressing cancer patients.
文摘Once thrombi have formed as part of the pathology defining myocardial infarction, ischemic stroke, peripheral arterial disease, deep venous thrombosis or other embolic disorders, the only clinically meaningful thrombolytic agents available for reversing the thrombogenic process are various plasminogen activators. These agents are enzymes that reverse fibrin polymerization underlying the coagulation process by converting endogenous plasminogen to plasmin, which cleaves the fibrin network to form increasingly smaller protein fragments, a process known as fibrinolysis. For the most part, the major clinically used thrombolytics, tissue plasminogen activator, urokinase and streptokinase, as well as the experimentally investigated agent staphylokinase, are the products of recombinant DNA technology, which permits molecular optimization of clinical efficacy. In all cases of molecular optimization and targeting, however, the primary challenge of thrombolytic therapy remains hemorrhagic side effects, which are especially devastating when they occur intracerebrally. Currently, the best strategy to ameliorate this adverse effect is nanoparticulate encapsulation or complexation, and many strategies of this sort are being actively pursued. This review summarizes the variety of targeted and untargeted thrombolytic formulations that have been investigated in preclinical studies.
