I think utg you've got to check or go all-in with AA. Preferably the first. It's a standard tactic so the c/o may not have raised, but wqith AQ you'd think he'd want to know where he stands so he raises, you go all in and he has to then put you on AA and fold.
On the flop, I think you've got to lay it down because he's either protecting the str8, or is drawing to a house with trips or two pair - in either case you're beat and the best you can hope for, really, is a split.