Downregulation of pro-surfactant protein B contributes to the recurrence of early-stage non-small cell lung cancer by activating PGK1-mediated Akt signaling.

Recurrence is one of the main causes of treatment failure in early-stage non-small cell lung cancer (NSCLC). However, there are no predictors of the recurrence of early-stage NSCLC, and the molecular mechanism of its recurrence is not clear. In this study, we used clinical sample analysis to demonstrate that low levels of expression of precursor surfactant protein B (pro-SFTPB) in primary NSCLC tissue compared to their adjacent tissues are closely correlated with recurrence and poor prognosis in early-stage NSCLC patients. In vitro and in vivo experiments showed that downregulation of pro-SFTPB expression activates the Akt pathway by upregulating PGK1, which promotes metastasis and tumorigenicity in NSCLC cells. We then demonstrated that pro-SFTPB suppresses the formation of the ADRM1/hRpn2/UCH37 complex by binding to ADRM1, which inhibits PGK1 deubiquitination, thus accelerating ubiquitin-mediated PGK1 degradation. In summary, our findings indicate that low expression of pro-SFTPB in primary NSCLC compared to their adjacent tissue has potential as a predictor of recurrence and poor prognosis in early-stage NSCLC. Mechanistically, downregulation of pro-SFTPB attenuates inhibition of ADRM1-deubiquitinated PGK1, resulting in elevated levels of PGK1 protein; this activates the Akt pathway, ultimately leading to the progression of early-stage NSCLC.