How to approach applying for a job where I previously turned down a role...

So when I graduated college I had a fall internship lined up at Company A, which I was really interested in working at. However, the company I was interning that summer, Company B, ended up offering me a full time role, which I accepted. I've been here nearly 2 years, and now Company A is hiring for my role. I ended up applying, and it seems like it would be a much better fit for me than Company B (which I'm kind of unhappy at).

One of my friends from college also works at Company A, and he sent me the job listing, so I have a connection there. I asked him who I should follow up with, and he gave me the names of the hiring managers. Now I'm wondering if I should address the fact that they had previously hired me or not. Because clearly they liked me enough to take me on as an intern, but it also seems like it could potentially be awkward that I turned them down. It's pretty understandable that a new graduate would take a full time role over an internship, and I gave them probably 2 months of notice, so I'd assume there's no hard feelings on their end.

How would you recommend I approach this in my follow up? Should I address it or not? And should I mention that one of their employees sent me the job, or just let him put a word in for me himself if he chooses?