Establishment and multi-omics characterization of a PD-1-resistant murine esophageal squamous cell carcinoma cell line.

Immunotherapy has revolutionized the treatment of esophageal squamous cell carcinoma (ESCC), but its clinical application is limited by low response rates and acquired resistance. The exploration of underlying is hampered by the absence of preclinical models that faithfully recapitulate the immune microenvironment and drug-resistant features of ESCC. Here, we established a novel murine ESCC cell line named mESCC-030, which was derived from primary ESCC tumors induced by 4-Nitroquinoline N-oxide (4-NQO) in C57BL/6 mice via consecutive in vivo selection. This cell line was validated by morphological observation and STR identification. Compared with primary parental cells, mESCC-030 exhibits stronger malignant proliferation, invasion and migration capabilities, and achieves 100% subcutaneous tumorigenicity in C57BL/6 mice. Moreover, the syngeneic graft tumors derived from this cell line display prominent resistance to PD-1 antibody therapy. Bulk transcriptomic profiling revealed that this cell line harbors enhanced proliferation-related pathways and diminished immune response pathways. Single-cell RNA sequencing of graft tumors identified a highly proliferative cell cluster in tumor tissues, along with an extremely low proportion of immune infiltrating cells. Taken together, the mESCC-30 cell line and its syngeneic tumors represent a typical immune-cold tumor model, providing a novel platform to uncover immunotherapy resistance mechanisms and develop combination therapeutic strategies.