Ubc9 promotes invasion and metastasis of lung cancer cells

Lung cancer is the leading cause of cancer-related mortality worldwide.The mortality is high mainly due to the lack of known effective screening procedures;there is a high tendency for early spread and systemic therapies do not cure metastaticdisease. Thus, it is important to investigate the molecular mechanism(s) of lungcancer development and, specifically, to identify an effective method by whichto inhibit the invasion and metastasis of lung cancer. Ubiquitin-conjugating enzyme9 (Ubc9), the sole conjugating enzyme for sumoylation, regulates protein functionand plays a key role in tumorigenesis. Whether Ubc9 is involved in the invasionand metastasis of lung cancer remains unknown. Herein, we report that Ubc9 exhibitsan important role in lung cancer invasion and metastasis. We first investigatedthe biological effect of Ubc9 on lung cancer by cloning the Ubc9 gene into a eukaryoticexpression plasmid and stably expressing it in the human small cell lung cancercell line NCI-H446 in order to observe any biological changes. We further analyzedthe effect of Ubc9 in an in vivo experiment, injecting NCI-H446 cells stably overexpressingUbc9 into nude mice and analyzing their metastatic ability. Our results demonstratedthat Ubc9 is expressed at higher levels in primary lung cancer tissue and metastaticnodules as compared to premalignant and/or normal tissue. Furthermore, we demonstratedthat upregulation of Ubc9 expression promotes migration and invasion. Ubc9 likelyplays an important role in cancer progression by promoting invasion and metastasisin lung cancer.