Deciphering the Role of ADAMTS6 in the Epithelial–Mesenchymal Transition of Lung Adenocarcinoma Cells

A disintegrin and metalloproteinase with thrombospondin motifs 6 (ADAMTS6) is an extracellular matrix (ECM) protease that promotes the invasion of lung adenocarcinoma (LUAD) cells. Herein, we investigate its role in epithelial-mesenchymal transition (EMT), a process that drives metastasis and drug resistance in LUAD. Re-analysis of microarray and RNA sequencing data from LUAD cells revealed that during EMT, TGF-β1 increased ADAMTS6 expression, presumably through the SMAD pathway, as SMAD2 loss completely blocked this effect. Moreover, ADAMTS6 was shown to occupy hub positions within TGF-β1-associated gene networks. Using additional datasets, we found that ADAMTS6 expression increased under other EMT-inducing conditions, including IL-1β induction and acquired gefitinib resistance, but decreased upon knockdown of Twist1, a master regulator of EMT. Knockout of ADAMTS6 repressed colony formation, migration, invasion, and doxorubicin resistance but enhanced cell–ECM adhesion in A549 cells. This effect was mediated by EMT inhibition, evidenced by upregulation of E-cadherin and downregulation of N-cadherin, vimentin, and Twist1, and was accompanied by suppressed nuclear translocation of the NF-κB p65 subunit. Re-analysis of transcriptomic data from patient tumors demonstrated that high ADAMTS6 expression correlated with the expression of EMT markers, further supporting the ADAMTS6–EMT link. Moreover, high ADAMTS6 expression was associated with worse survival prognosis. Overall, ADAMTS6 promotes EMT in LUAD cells and may be considered a marker of this process, as well as a potential therapeutic target for its inhibition.