Effects of Irradiation Combined with Trastuzumab on Myocardial Cell Line H9c2 In Vitro

Abstract

<h3>Purpose/Objective(s)</h3> The current clinical guidelines do not make clear restrictions or affirmation on whether chest radiotherapy can be delivered currently with trastuzumab. We aim to analyze the effect of trastuzumab combined with dose gradient X-ray irradiation on H9c2 cardiomyocytes and detect the relevant mechanism. <h3>Materials/Methods</h3> Trastuzumab was given at the same time with X-ray irradiation of H9c2 cardiomyocytes with dose gradient (0, 2, 5, 10, 15gy). Flow cytometry was used to detect the proportion of apoptosis, a cell counting kit was used to detect the viability of cells, and WB was used to detect apoptosis related proteins for analyzing the damage effect of irradiation combined with trastuzumab on cardiomyocytes. To analyze the mechanism of trastuzumab aggravating myocardial radiotoxicity by detecting ROS content, Akt protein phosphorylation and DNA damage. <h3>Results</h3> 1. Flow cytometry and WB suggested that irradiation could promote the apoptosis of H9c2 cardiomyocytes, which was positively correlated with the dose of irradiation; after trastuzumab treatment, apoptosis was further improved. 2. A cell counting kit assay showed that irradiation combined with trastuzumab could superimpose the inhibitory effect on cardiomyocyte activity. 3. Compared with irradiation alone, irradiation combined with trastuzumab significantly inhibited the phosphorylation of Akt molecules. 4. Trastuzumab could promote the aggregation of ROS in cells by Flow cytometry, and enhance DNA damage induced by irradiation by the formation of fluorescence focus of γ - H2AX. <h3>Conclusion</h3> 1. Radiation injury to isolated cardiomyocytes was dose-dependent. Meanwhile, trastuzumab aggravated the toxicity of irradiation on cardiomyocytes. 2. Trastuzumab may aggravate myocardial radiation injury by inhibiting Akt phosphorylation, promoting ROS accumulation in cells and promoting DNA damage.