Trastuzumab-Doxorubicin Conjugate Provides Enhanced Anti-Cancer Potency and Reduced Cardiotoxicity

Abstract

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.

A light-responsive, self-immolative linker for controlled drug delivery via peptide- and protein-drug conjugates

“…Zhang et al conjugated DOX to trastuzumab via an acidlabile MMCCH linker. 42 At pH 7.4, both linker degradation and drug release were rather slow (the release rate was 25% per day), but in a lysosomal environment (pH 5.4), 80% of the DOX was released from the ADC aer 24 h. Our trastuzumab-PC4AP-DOX conjugate was much more stable than the trastuzumab-MMCCH-DOX conjugate under physiologically relevant conditions. In addition, aer being triggered by a biocompatible stimulus, drug release was more efficient from the former than from the latter.…”

“…39,40 As the antibody, we chose trastuzumab, a clinical monoclonal IgG that recognizes and induces internalization of HER2, a receptor that is highly expressed in some breast cancer cell lines. 41,42 To prepare trastuzumab-DOX conjugates with the PC4AP linker, we treated trastuzumab with 4 equiv. of tris(2-carboxyethyl)phosphine (TCEP) in phosphate-buffered saline for 2 h to reduce the interchain disulde bonds, and then incubated it with 8 equiv.…”

Enhanced 4T1 Breast Carcinoma Anticancer Activity by Co-Delivery of Doxorubicin and Curcumin with Core–Shell Drug-Carrier Based on Heparin Modified Poly(L-lactide) Grafted Polyethylenimine Cationic Nanoparticles

“…First, the NPs complex serves as a slowrelease preparation of the anthracycline and prevents rapid increase into the blood and cardiac tissue. [43][44] Second, heparin may reduce the binding of DOX to the heart blood vessel walls by competitive inhibition between heparin and acidic mucopolysaccarides of the vessel walls, such as heparin sulfate and chondroitin sulfate. 45 Third, the DOX-Cur NPs complex may reduce the intake of DOX into the cardiac tissue, if the complex enters the cells by endocytosis.…”

Doxorubicin conjugated with a trastuzumab epitope and an MMP-2 sensitive peptide linker for the treatment of HER2-positive breast cancer

“…Despite its observed clinical efficacy, such a simple drug combination is generally not recommended due to low selectivity and severe cardiotoxicity coming from the cumulative effects of both trastuzumab and DOX (Wonders & Reigle, 2009 , Rochette et al., 2015 ). In this context, a trastuzumab-DOX conjugate has been recently developed and provides improved selectivity in drug delivery and reduced cardiotoxicity by relying on antibody trastuzumab-mediated specific recognition of the tumor antigen HER2 (Tarcic & Yarden, 2013 ; Zhang et al., 2013 ). However, the trastuzumab-DOX conjugate has had incomplete penetration of tumors due to the “binding site barrier” effect (Aina et al., 2002 ; Graff & Wittrup, 2003 ; Thurber et al., 2008 ), which is consistent with the results for most other antibody-drug conjugates (ADC).…”