277 Establishment of novel syngeneic mouse gastric cell line models for CLDN18.2 CAR-T therapy

<h3>Background</h3> Only a few syngeneic mouse cell line models are available for gastric cancer. <h3>Methods</h3> We have established a cell line from an autochthonous gastric cancer formed in the stomach of a female genetically-engineered mouse (figure 1). <h3>Results</h3> This cell line recapitulated morphological and molecular features of human intestinal gastric cancer and readily formed a tumor when injected into syngeneic mice. The cell line overexpressed the isoform 2 of claudin 18, an important molecular therapeutic target in human gastric adenocarcinomas. Anti-mouse CLDN18.2 CAR-T suppressed tumor growth and prolonged survival of mice bearing the syngeneic graft. According to mass spectrometry analysis, the cells had high CLDN18.2 content. <h3>Conclusions</h3> Thus, we have generated a useful resource for the development of immunotherapeutics. <h3>Consent</h3> Written informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.