MARCH8 ubiquitinates and degrades CEMIP to induce colorectal cancer cell ferroptosis through inactivating PI3K/AKT pathway

Background

Cell migration-inducing and hyaluronan-binding protein (CEMIP) is found to act as an oncogene in colorectal cancer (CRC) progression, but the underlying molecular mechanisms need to be further elucidated.

Methods

The mRNA and protein levels of CEMIP and membrane-associated ring-CH-type finger 8 (MARCH8) were examined by qRT-PCR and western blot. Cell functions were detected by CCK8 assay, colony formation assay and transwell assay. The levels of ROS, Fe^2 +, GSH, and MDA were examined to evaluate cell ferroptosis. The interaction between MARCH8 and CEMIP was assessed by Co-IP assay and ubiquitination assay. The protein levels of ferroptosis-related markers (ACSL4, GPX4 and FTH1) and PI3K/AKT-related markers were tested using western bolt. The anti-tumor effect of MARCH8 was further confirmed by constructing xenograft tumor models.

Results

CEMIP expression was higher in CRC tissues and cells. CEMIP knockdown could suppress CRC cell proliferation, migration, invasion, and enhance ferroptosis. MARCH8 ubiquitinated CEMIP to decrease its expression, thus inhibiting CRC cell proliferation, metastasis and inducing ferroptosis. And CEMIP overexpression could abolish the anti-proliferation, anti-metastasis and pro-ferroptosis effect of MARCH8. Also, MARCH8 overexpression repressed the activity of PI3K/AKT pathway, and CEMIP upregulation partially reversed this effect. In vivo experiments suggested that MARCH8 reduced CRC tumorigenesis by inducing ferroptosis.

Conclusion

MARCH8 promoted CRC cell ferroptosis via inhibiting PI3K/AKT pathway by enhancing the ubiquitination and degradation of CEMIP.