Histone lactylation enhances GCLC expression and thus promotes chemoresistance of colorectal cancer stem cells through inhibiting ferroptosis.

Colorectal cancer stem cells (CCSCs) play a critical role in mediating chemoresistance. Lactylation is a post-translational modification induced by lactate that regulates gene expression. However, whether lactylation affects the chemoresistance of CCSCs remains unknown. Here, we demonstrate that histone lactylation enhances CCSC chemoresistance both in vitro and in vivo. Furthermore, our findings showed that p300 catalyzes the lactylation of histone H4 at K12, whereas HDAC1 facilitates its delactylation in CCSCs. Notably, lactylation at H4K12 (H4K12la) upregulates GCLC expression and inhibits ferroptosis in CCSCs, and the inhibition of p300 or LDHA decreases H4K12la levels, thereby increasing the chemosensitivity of CCSCs. Additionally, the GCLC inhibitor BSO promotes ferroptosis and sensitizes CCSCs to oxaliplatin. Taken together, these findings suggest that histone lactylation upregulates GCLC to inhibit ferroptosis signaling, thus enhancing CCSC chemoresistance. These findings provide new insights into the relationship between cellular metabolism and chemoresistance and suggest potential therapeutic strategies targeting p300, LDHA, and GCLC. We showed that histones H4K12 lactylation promoted chemoresistance in CSCs. p300 catalyzes the lactylation of histone H4 at K12, HDAC1 inhibits the histone lactylation at the same site. H4K12la in CSCs regulates the expression of the ferroptosis-related gene GCLC, thereby inhibiting ferroptosis and leading to chemoresistance. Targeting the p300, LDHA, or GCLC may be overcome tumor chemoresistance.