Other effects can still modify enchanted creature’s power and/or toughness as they would any other creature, and their durations are not affected. For example, Invigorate can give the creature +4/+4 until end of turn. While its toughness is boosted, that toughness can be reduced as a cost to activate its loyalty abilities. However, once the turn ends and Invigorate wears off, if the creature’s toughness is 0 or less, it would be put into a graveyard as a state-based action.