Pathological and biological significance of the specific glycan, TRA-1-60, on aggressive gastric adenocarcinoma.

The glycans form a unique complex on the surface of cancer cells and play a pivotal role in tumor progression, impacting proliferation, invasion, and metastasis. TRA-1-60 is a glycan that was identified as a critical marker for the establishment of fully reprogrammed inducible pluripotent stem (iPS) cells. Its expression has been detected in multiple cancer tissues, including embryonal carcinoma, prostate cancer, and pancreatic cancer, but the biological and pathological characterization of TRA-1-60-expressing tumor cells still remains unclear within various types of malignancies. Here, we report the biological characteristics of TRA-1-60-expressing gastric cancer cells, especially those with its cell surface expression, and the therapeutic significance of targeting TRA-1-60. The cells with cell membrane expression of TRA-1-60 were mainly observed in the invasive area of patient gastric cancer tissues and correlated with advanced stages of the disease based on histopathological and clinicopathological analyses. In vitro analysis using a scirrhous gastric adenocarcinoma line, HSC-58, which highly expresses TRA-1-60 on its plasma membrane, revealed increased stress-resistant mechanisms, supported by the upregulation of glutathione synthetase (GSS) and NCF-1 (p47phox) via lipid-ROS regulatory pathways, as detected by RNA-seq analysis followed by oxidative stress gene-profiling. Our in vivo therapeutic study using the TRA-1-60-targeting antibody-drug conjugate (ADC), namely Bstrongomab conjugated Monomethyl auristatin E (MMAE), showed robust efficacy in a mouse model of peritoneal carcinomatosis induced by intraperitoneal xenograft of HSC-58, by markedly reducing massive tumor ascites. Thus, targeting the specific cell surface glycan, TRA-1-60, shows significant therapeutic impact in advanced-stage gastric cancers. (243 words).