Ado-Trastuzumab Emtansine Targets Hepatocytes Via Human Epidermal Growth Factor Receptor 2 to Induce Hepatotoxicity

Abstract

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) approved for the treatment of HER2-positive metastatic breast cancer. It consists of trastuzumab, a humanized mAb directed against HER2, and a microtubule inhibitor, DM1, conjugated to trastuzumab via a thioether linker. Hepatotoxicity is one of the serious adverse events associated with T-DM1 therapy. Mechanisms underlying T-DM1-induced hepatotoxicity remain elusive. Here, we use hepatocytes and mouse models to investigate the mechanisms of T-DM1-induced hepatotoxicity. We show that T-DM1 is internalized upon binding to cell surface HER2 and is colocalized with LAMP1, resulting in DM1-associated cytotoxicity, including disorganized microtubules, nuclear fragmentation/multiple nuclei, and cell growth inhibition. We further demonstrate that T-DM1 treatment significantly increases the serum levels of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in mice and induces inflammation and necrosis in liver tissues, and that T-DM1-induced hepatotoxicity is dose dependent. Moreover, the gene expression of TNFa in liver tissues is significantly increased in mice treated with T-DM1 as compared with those treated with trastuzumab or vehicle. We propose that T-DM1-induced upregulation of TNFa enhances the liver injury that may be initially caused by DM1-mediated intracellular damage. Our proposal is underscored by the fact that T-DM1 induces the outer mitochondrial membrane rupture, a typical morphologic change in the mitochondrial-dependent apoptosis, and mitochondrial membrane potential dysfunction. Our work provides mechanistic insights into T-DM1-induced hepatotoxicity, which may yield novel strategies to manage liver injury induced by T-DM1 or other ADCs. Mol Cancer Ther; 15(3); 480-90. Ó2015 AACR.

Liver Microvascular Injury and Thrombocytopenia of Antibody–Calicheamicin Conjugates in Cynomolgus Monkeys—Mechanism and Monitoring

“…The overall similarity of effects on platelets and liver with T-DM1 and antibody-calicheamicin conjugates suggests that a similar underlying mechanism may contribute to the thrombocytopenia and liver injury with both classes of drugs. However, these similarities require further investigation in light of another recently proposed hypothesis for T-DM1-mediated liver injury, namely HER2 expression by hepatocytes (45).…”

Antibody-Drug Conjugates for the Therapy of Thoracic Malignancies

“…52 Because of mortality from liver failure reported in patients treated with T-DM1, hepatotoxicity is one of the black box warnings on FDA labeling. 57,58 Preclinical models suggest that T-DM1 is able to bind to HER2 on hepatocytes, leading to its internalization via endocytosis and subsequent release of toxophore in lysosomes to induce microtubule destabilization and hepatocyte death. 58 Hepatotoxicity was one of the dose-limiting toxicities in the phase I study of Rova-T. 59…”

Bilirubin detoxification using different phytomaterials: characterization and in vitro studies

“…28,37 Cells were washed and permeabilized with 0.1% Triton X-100 for 5 minutes, fluorescein isothiocyanate (FITC)-labeled phalloidin added, and kept incubated for 40 minutes. [38][39][40] Cells were washed with DPBS and 0.1% Triton X-100 for 4 minutes. Samples were mounted with DAPI-Fluoroshield (Sigma-Aldrich) for 10 minutes, then washed to remove the excess DAPI.…”

“…Similarly, the 3D cultured cells were allowed to grow in Matrigel and collagen for 10 days. 24,38 Matrigel acts as a framework for cells to grow and mimic the conditions inside the human body. The rate of growth in 3D culture is much slower compared to normal culture, especially in the case of normal cells.…”