TIMP1 promotes colorectal cancer progression through inhibition of ferroptosis via the ubiquitin-mediated regulation of NRF2.

[BACKGROUND] Colorectal cancer (CRC) is a major global health burden with limited therapeutic efficacy, highlighting the need for novel pathogenic insights and therapeutic targets. Tissue Inhibitor of Metalloproteinase 1 (TIMP1) is overexpressed in CRC and correlates with poor prognosis, but its functional role and underlying mechanisms, particularly in relation to ferroptosis, remain unclear.

[METHODS] TIMP1 expression and its prognostic value were analyzed in clinical CRC specimens and public databases. The functional impact of TIMP1 on CRC progression was assessed using in vitro assays (CCK-8, colony formation, Transwell, wound healing) and in vivo subcutaneous xenograft models in nude mice. Ferroptosis was evaluated by measuring lipid peroxidation (MDA), antioxidant capacity (SOD), intracellular ROS/Fe levels, and expression of key ferroptosis regulators (GPX4, SLC7A11). Molecular mechanisms were investigated through co-immunoprecipitation, ubiquitination assays, protein stability experiments, and rescue studies with ferroptosis inhibitor Ferrostatin-1 or NRF2 overexpression.

[RESULTS] TIMP1 was significantly upregulated in CRC tissues and cell lines, and high TIMP1 expression predicted poor patient survival. TIMP1 knockdown suppressed CRC cell proliferation, migration, and tumor growth in vivo, while TIMP1 overexpression promoted these phenotypes. Mechanistically, TIMP1 inhibited ferroptosis, as evidenced by reduced lipid peroxidation and increased expression of GPX4 and SLC7A11. TIMP1 physically interacted with nuclear factor erythroid 2-related factor 2 (NRF2) and stabilized NRF2 protein by competitively binding the E3 ubiquitin ligase Synoviolin 1 (SYVN1), thereby impairing NRF2 ubiquitination and degradation. The oncogenic effects of TIMP1 were dependent on NRF2, as NRF2 overexpression rescued the phenotypic and ferroptosis-related alterations induced by TIMP1 knockdown both in vitro and in vivo.

[CONCLUSIONS] Our study identifies TIMP1 as a critical promoter of CRC progression through inhibition of ferroptosis. TIMP1 stabilizes NRF2 by sequestering SYVN1 and suppressing NRF2 ubiquitination, leading to enhanced ferroptosis resistance and tumor malignancy. The TIMP1-SYVN1-NRF2 axis represents a novel regulatory mechanism and a promising therapeutic target for CRC treatment.