When physician-scientist Jay Bradner left the Dana-Farber Cancer Institute last year, he left behind some key scientific work that had already intrigued a group of investors. Bradner is now president of the Novartis Institutes for Biomedical Research, but his Dana-Farber research continued in the hands of others. It’s now the basis of a new startup called C4 Therapeutics that debuts today with a hefty financing round.