ATF4 and lung cancer: To clarify whether DENV modulated UPR regulates autophagic activity in the generally used cell lines, human hepatoma Huh7 and lung cancer A549 cells were infected with DENV2 at the MOI of 10, and the cell lysates were collected at 12 h, 24 h, 36 h and 48 h p.i. The expression levels of GRP78 (a marker of ER stress), ATF4 (a marker of PERK pathway), IRE1, ATF6, LC3 II (autophagy marker) as well as NS1 were investigated during DENV2 infection.