De Bartolo Anna, Romeo Naomi, Marrone Alessandro, Rago Vittoria, Granieri Maria Concetta, Vommaro Maria Luigia, Cupelli Arianna, Cerra Maria Carmela, Indiveri Cesare, Ronca Raffaele, Cantile Maria, Sanna Riccardo, Rocca Carmine, Angelone Tommaso
Department of Biology, E. and E. S. (DiBEST), Cellular and Molecular Cardiovascular Physiology and Pathophysiology Laboratory, University of Calabria, Cosenza, Italy.
Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Cosenza, Italy.
Acta Pharmacol Sin. 2025 Mar;46(3):618-631. doi: 10.1038/s41401-024-01397-3. Epub 2024 Oct 16.
Fragment crystallizable gamma receptors (FcγRs) mediate various cellular responses with significant cardiovascular implications. They contribute to the anticancer activity of trastuzumab (TRZ), a recombinant humanized monoclonal antibody that interferes with human epidermal growth factor receptor 2 (HER2), thereby blocking its physiological function in cardiac cells. This is responsible for cardiac complications that hamper TRZ clinical application. In this study we investigated the involvement of FcγRs in the TRZ cardiotoxicity. We used a recombinant antigen-binding fragment (Fab) of TRZ (rFab-HER2) to examine whether the absence of the Fc region resulted in fewer cardiomyocyte toxicity while preserving TRZ's ability to inhibit HER2. When exposed to rFab-HER2, AC16 human adult ventricular cardiomyocytes were less vulnerable to damage and death, than to TRZ. Specifically, TRZ exhibited cytotoxicity at a lower concentration (150 µg/mL, corresponding to ~1 µM) compared to rFab-HER2 (250 µg/mL, corresponding to ~5 µM). Like TRZ, rFab-HER2 negatively modulated HER2 levels in cardiomyocyte (without inducing cytotoxic activity in BJ human fibroblast cells that either did not express or express very low levels of HER2) and inhibited the downstream ERK/AKT cascades. But rFab-HER2 did not alter cardiomyocyte mitochondrial dynamic balance, and affect apoptosis and inflammation, while it limited cytosolic and mitochondrial ROS indicators. On contrary, the Fc region (50-250 μg/mL) exerted direct cytotoxic action on cardiomyocytes (but not on human fibroblasts that lacked Fc receptors). TRZ (150 μg/mL) markedly upregulated the expression level of FcγRIIA (a FcγRs strongly involved in TRZ-induced antibody-dependent cellular toxicity) in cardiomyocytes, whereas the Fab fragment (150 μg/mL) had no effect. Our results demonstrate that Fc region plays an important pathogenic role in TRZ-induced cardiomyocyte toxicity. In addition, targeting FcγRIIA might contribute to the off-target effects of TRZ therapy.
可结晶片段γ受体（FcγRs）介导多种具有重要心血管影响的细胞反应。它们有助于曲妥珠单抗（TRZ）的抗癌活性，TRZ是一种重组人源化单克隆抗体，可干扰人表皮生长因子受体2（HER2），从而阻断其在心脏细胞中的生理功能。这会导致心脏并发症，阻碍TRZ的临床应用。在本研究中，我们调查了FcγRs在TRZ心脏毒性中的作用。我们使用TRZ的重组抗原结合片段（Fab）（rFab-HER2）来研究Fc区域的缺失是否会在保留TRZ抑制HER2能力的同时降低心肌细胞毒性。当暴露于rFab-HER2时，AC16成人人类心室心肌细胞比暴露于TRZ时更不易受到损伤和死亡。具体而言，与rFab-HER2（250μg/mL，约相当于5μM）相比，TRZ在较低浓度（150μg/mL，约相当于1μM）时就表现出细胞毒性。与TRZ一样，rFab-HER2负向调节心肌细胞中的HER2水平（在不表达或表达极低水平HER2的BJ人成纤维细胞中不诱导细胞毒性活性）并抑制下游ERK/AKT级联反应。但rFab-HER2不会改变心肌细胞线粒体动态平衡，也不会影响细胞凋亡和炎症，同时它限制了胞质和线粒体活性氧指标。相反，Fc区域（50 - 250μg/mL）对心肌细胞具有直接细胞毒性作用（但对缺乏Fc受体的人成纤维细胞没有作用）。TRZ（150μg/mL）显著上调心肌细胞中FcγRIIA（一种在TRZ诱导的抗体依赖性细胞毒性中起重要作用的FcγRs）的表达水平，而Fab片段（150μg/mL）则没有影响。我们的结果表明，Fc区域在TRZ诱导的心肌细胞毒性中起重要的致病作用。此外，靶向FcγRIIA可能有助于解释TRZ治疗的脱靶效应。
