I am no pureMVC expert (far from it, as I'm only beginning)
But, it seems that your questions isn't really PureMVC related but more Flash/Flex/ActionScript in general?
And yes, you certainly can load information from a database using some serverside language (most sites do). Look into the URLLoader object in the documentation. And search a bit for "actionscript 3 loading xml" (as xml is my preferred weapon of choice for transferring data