Identification of SUV39H2 as a potential oncogene in lung adenocarcinoma.

BACKGROUND: SUV39H2 (suppressor of variegation 3-9 homolog 2), which introduces H3K9me3 to induce transcriptional repression, has been reported to play critical roles in heterochromatin maintenance, DNA repair, and recently, carcinogenesis. Dysregulation of SUV39H2 expression has been observed in several types of cancers. However, neither the genomic landscape nor the clinical significance of SUV39H2 in lung adenocarcinoma has been probed comprehensively.

METHODS: In this research, we conducted bioinformatics analysis to primarily sort out potential genes with dysregulated expressions. After we identified SUV39H2, RNA-seq was performed for a high-throughput evaluation of altered gene expression and dysregulated pathways, followed by a series of validations via RT-qPCR and bioinformatics analyses. Finally, to assess the potential oncogenic role of SUV39H2, we employed the invasion assay and clone formation assay in vitro and tumorigenesis assays in mouse models in vivo.

RESULTS: Through bioinformatics analyses, we found that SUV39H2 underwent a severe upregulation in the tumor tissue, which was also confirmed in the surgically removed tissues. Overexpression of SUV39H2 was mainly associated with its amplification and with shorter patient overall survival. Then, the RNA-seq demonstrated that TPM4, STOM, and OPTN might be affected by the loss of function of SUV39H2. Finally, in vitro and in vivo experiments with SUV39H2 knockdown all suggested a potential role of SUV39H2 in both carcinogenesis and metastasis.

CONCLUSIONS: SUV39H2 expression was elevated in lung adenocarcinoma. TPM4, OPTN, and STOM were potentially regulated by SUV39H2. SUV39H2 might be a potential oncogene in lung adenocarcinoma, mediating tumorigenesis and metastasis.