Background: Colorectal cancer (CRC) is one of the highly prevalent malignancies worldwide and a leading cause of cancer-related mortality, with limited therapeutic options, particularly in advanced stages. This study investigates the role of the FOS-like antigen 1 (FOSL1)/ankyrin repeat domain 22 (ANKRD22) axis in regulating CRC through mitochondrial function.

Methods: ANKRD22 expression patterns in CRC tissues and adjacent normal tissues were analyzed using The Cancer Genome Atlas (TCGA) data. In vitro experiments were performed using CRC cell lines, where FOSL1 and ANKRD22 expression was manipulated via plasmid-mediated overexpression or short hairpin RNA (shRNA)-based silencing. Stemness was assessed using sphere formation assays, cloning assays, and Western blotting to profile expression of stemness-related proteins. FOSL1 binding to the ANKRD22 promoter was validated by luciferase reporter and chromatin immunoprecipitation (ChIP) assays. Mitochondrial status was evaluated by measuring reactive oxygen species (ROS), calcium levels, and membrane potential.

Results: TCGA data and in vitro analyses revealed that both FOSL1 and ANKRD22 were highly expressed in CRC cells (p < 0.05). Overexpression of FOSL1 or ANKRD22 in CRC cells significantly enhanced cell proliferation, sphere formation capacity, clonogenic potential, and expression of stemness-related proteins (p < 0.05). FOSL1 directly bound to the ANKRD22 promoter and transcriptionally upregulated its expression (p < 0.05). FOSL1 overexpression decreased mitochondrial ROS, calcium, and membrane potential (p < 0.05). Crucially, silencing ANKRD22 reversed the effects of FOSL1 overexpression on stemness (sphere formation, clonogenicity, stemness-related proteins) and mitochondrial parameters (ROS, calcium, membrane potential) (p < 0.05).

Conclusion: FOSL1 transcriptionally activates ANKRD22, which regulates mitochondrial function by controlling ROS, calcium, and membrane potential, to modulate CRC development. Targeting the FOSL1/ANKRD22 axis may represent a strategy to impede CRC progression.