LC3B upregulation by NANOG promotes immune resistance and stem-like property through hyperactivation of EGFR signaling in immune-refractory tumor cells.

Kim, Suyeon; Cho, Hanbyoul; Hong, Soon-Oh; Oh, Se Jin; Lee, Hyo-Jung; Cho, Eunho; Woo, Seon Rang; Song, Joon Seon; Chung, Joon-Yong; Son, Sung Wook; Yoon, Sang Min; Jeon, Yu-Min; Jeon, Seunghyun; Yee, Cassian; Lee, Kyung-Mi; Hewitt, Stephen M; Kim, Jae-Hoon; Song, Kwon-Ho; Kim, Tae Woo

Immune selection drives tumor cells to acquire refractory phenotypes. We previously demonstrated that cytotoxic T lymphocyte (CTL)-mediated immune pressure enriches NANOG+ tumor cells with stem-like and immune-refractory properties that make them resistant to CTLs. Here, we report that the emergence of refractory phenotypes is highly associated with an aberrant macroautophagic/autophagic state of the NANOG+ tumor cells and that the autophagic phenotype arises through transcriptional induction of MAP1LC3B/LC3B by NANOG. Furthermore, we found that upregulation of LC3B expression contributes to an increase in EGF secretion. The subsequent hyperactivation of EGFR-AKT signaling rendered NANOG+ tumor cells resistant to CTL killing. The NANOG-LC3B-p-EGFR axis was preserved across various types of human cancer and correlated negatively with the overall survival of cervical cancer patients. Inhibition of LC3B in immune-refractory tumor models rendered tumors susceptible to adoptive T-cell transfer, as well as PDCD1/PD-1 blockade, and led to successful, long-term control of the disease. Thus, our findings demonstrate a novel link among immune-resistance, stem-like phenotypes, and LC3B-mediated autophagic secretion in immune-refractory tumor cells, and implicate the LC3B-p-EGFR axis as a central molecular target for controlling NANOG+ immune-refractory cancer.