The H3K4 methyltransferase SETD1A is required for proliferation of non-small cell lung cancer cells by promoting S-phase progression.

Epigenetic dysregulation has been strongly implicated in carcinogenesis and is one of the mechanisms that contribute to the development of lung cancer. Using genome-wide CRISPR/Cas9 library screening, we showed SET domain-containing protein 1A (SETD1A) is an essential epigenetic modifier of the proliferation of NSCLC H1299 cells. Depletion of SETD1A strikingly inhibited the proliferation of NSCLC cells. IHC staining and bioinformatics showed that SETD1A is upregulated in lung cancer. Kaplan-Meier survival analysis indicated that high expression of SETD1A is associated with poor prognosis of patients with NSCLC. We revealed that loss of SETD1A inhibits DNA replication and induces replication stress accompanied by impaired fork progression. In addition, transcription of CDC7 and TOP1, which are involved in replication origin activation and fork progression, respectively, was significantly reduced by knockdown of SETD1A. Taken together, these findings demonstrated SETD1A is a critical epigenetic modifier of NSCLC cell proliferation by promoting the transcription of a subset of DNA replication-associated genes.