Pentagalloyl glucose targets the JAK1/JAK3-STAT3 pathway to inhibit cancer stem cells and epithelial–mesenchymal transition in 5-fluorouracil-resistant colorectal cancer

• A combination of transcriptomics, proteomics, and molecular biology were used to detect and evaluate the antitumor activity and mechanisms of PGG against 5-FU-resistant colorectal cancer. • The mechanism of PGG resistance to 5-FU-resistant colorectal cancer was Clarified. • The great promise of PGG against drug-resistant cancers was discovered, and bringing hope for the salvage of drug-resistant cancers. Colorectal cancer (CRC) resistance to 5-fluorouracil (5-FU), primarily driven by cancer stem cells (CSCs) and epithelial–mesenchymal transition (EMT), remains a major clinical challenge, necessitating novel therapeutic strategies. This study aims to evaluate the therapeutic potential of pentagalloyl glucose (PGG), a bioactive compound derived from Bouea macrophylla seeds, in overcoming 5-FU resistance in CRC. Anti-tumor effects of PGG were investigated using two- and three-dimensional (2D and 3D) cell culture models and subcutaneous xenograft and metastatic mouse models. Transcriptome sequencing, western blotting, and pharmacological inhibitors were employed to elucidate the underlying molecular mechanisms. PGG demonstrated potent anti-CSC activity; suppressed EMT-driven invasion and metastasis; and induced apoptosis in 2D monolayers, 3D spheroid models, and xenograft tumor models. Mechanistically, PGG selectively inhibited the JAK1/JAK3-STAT3 signaling pathway, considerably reducing STAT3 phosphorylation. This disruption downregulated the expression of CSC markers (CD133 and CD44), EMT regulators (N-cadherin and vimentin), and anti-apoptotic proteins (Bcl-2), effectively sensitizing 5-FU-resistant CRC to therapy. PGG inhibit dual-target of CSCs and EMT via JAK1/JAK3-STAT3 signaling pathway in 5-FU-resistant CRC, providing a novel therapeutic approach to overcome chemoresistance.