Abrogation of esophageal carcinoma development in miR-31 knockout rats

Significance ESCC is a deadly disease with few prevention or treatment options. In a dietary Zn deficiency-promoted rat ESCC model with miR-31–controlled inflammation pathway up-regulation, systemic antimiR-31 reduces miR-31 level and inflammation, suppressing ESCC development. We identified Egln3 as a direct miR-31 target and developed a constitutive miR-31 knockout rat model. Interactions of oncogenic miR-31, EGLN3 down-regulation, and inflammation occur in rat and human ESCC tissue. Since miR-31 genetic knockout prevents Zn deficiency-associated ESCC by eliminating or greatly reducing the entire miR-31-EGLN3/STK40-NF-κB–controlled inflammatory process, we conclude that miR-31 and downstream signaling proteins should be tested as prognostic and therapeutic targets and inexpensive Zn supplementation should be implemented for ESCC prevention in deficient populations.
MicroRNA-31 (miR-31) is overexpressed in esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary Zn deficiency and inflammation. In a Zn deficiency-promoted rat ESCC model with miR-31 up-regulation, cancer-associated inflammation, and a high ESCC burden following N-nitrosomethylbenzylamine (NMBA) exposure, systemic antimiR-31 delivery reduced ESCC incidence from 85 to 45% (P = 0.038) and miR-31 gene knockout abrogated development of ESCC (P = 1 × 10−6). Transcriptomics, genome sequencing, and metabolomics analyses in these Zn-deficient rats revealed the molecular basis of ESCC abrogation by miR-31 knockout. Our identification of EGLN3, a known negative regulator of nuclear factor κB (NF-κB), as a direct target of miR-31 establishes a functional link between oncomiR-31, tumor suppressor target EGLN3, and up-regulated NF-κB–controlled inflammation signaling. Interaction among oncogenic miR-31, EGLN3 down-regulation, and inflammation was also documented in human ESCCs. miR-31 deletion resulted in suppression of miR-31–associated EGLN3/NF-κB–controlled inflammatory pathways. ESCC-free, Zn-deficient miR-31−/− rat esophagus displayed no genome instability and limited metabolic activity changes vs. the pronounced mutational burden and ESCC-associated metabolic changes of Zn-deficient wild-type rats. These results provide conclusive evidence that miR-31 expression is necessary for ESCC development.