The mutually exclusive staining of cycling CDX2+ and non-cycling PROX1+ cells in human CRC organoids, mouse xenografted tumors, and human CRC specimens. Inhibition of mTORC1 triggers conversion from CDX2+ cells to PROX1+ cells in human CRC organoids and mouse xenografted tumors.
See details in Ohata, et. al. (2023) Cell Rep.
Hirokazu Ohata, Daisuke Shiokawa, Hiroaki Sakai, Yusuke Kanda, Yoshie Okimoto, Syuzo Kaneko, Ryuji Hamamoto, Hitoshi Nakagama, Koji Okamoto (2023) PROX1 induction by autolysosomal activity stabilizes persister-like state of colon cancer via feedback repression of the NOX1-mTORC1 pathway., Cell reports, pp. 112519
Published in 2023 May 17 (Electronic publication in May 17, 2023, midnight )
(Abstract) Cancer chemoresistance is often attributed to slow-cycling persister populations with cancer stem cell (CSC)-like features. However, how persister populations emerge and prevail in cancer remains obscure. We previously demonstrated that while the NOX1-mTORC1 pathway is responsible for proliferation of a fast-cycling CSC population, PROX1 expression is required for chemoresistant persisters in colon cancer. Here, we show that enhanced autolysosomal activity mediated by mTORC1 inhibition induces PROX1 expression and that PROX1 induction in turn inhibits NOX1-mTORC1 activation. CDX2, identified as a transcriptional activator of NOX1, mediates PROX1-dependent NOX1 inhibition. PROX1-positive and CDX2-positive cells are present in distinct populations, and mTOR inhibition triggers conversion of the CDX2-positive population to the PROX1-positive population. Inhibition of autophagy synergizes with mTOR inhibition to block cancer proliferation. Thus, mTORC1 inhibition-mediated induction of PROX1 stabilizes a persister-like state with high autolysosomal activity via a feedback regulation that involves a key cascade of proliferating CSCs.