Re: If the Lizard was the villain in Sam Raimi's Spider-Man 4...
By all accounts, it would have been the Vulture. However, to answer your question, I suppose something would have to push Curt into wanting to research regeneration. Then Curt would have to work alongside some researchers/corporation that would fund the research.
"I am for no master nor moral persuasion. I am for myself. What your yearning soul, madam, might mistake for loyalty to person or Purpose is merely a firm and, aye, principled determination to accept responsibility only for myself and my own actions." - Elric of Melnibone, The Revenge of the Rose (Elric: Swords and Roses).