BECN1 and infection: To elucidate the underlying mechanisms of the different patterns of autophagy modulation in various drug-resistant A549 cells upon NDV/FMW infection, we examined the class I PI3K/Akt/mTOR/p70S6K and class III PI3K/Beclin-1 pathways, which negatively (the former) or positively (the latter) regulate autophagosome formation [20, 21].