Can I email a list of contacts I received from a trusted source?

Hi there,
I want to make sure I'm following Constant Contact's rules correctly.

A friend of mine used to manage a now-defunct newsletter with a strong local following. She shared her email list with me, and I’d like to send a one-time invitation to those contacts inviting them to subscribe to my nonprofit newsroom's newsletter.

These people haven’t opted in directly to my list, but they were previously subscribed to a similar local news publication and have a likely interest in what we’re doing.

Am I allowed to upload this list and send them a single, clearly labeled invitation — with an unsubscribe option — asking if they'd like to opt in to my newsletter?

Thanks for any clarification!