Answer: not really, or at least, not with as little work as I'd been hoping.
I set up six accounts and fed them, through Twitterfeed, with news stories relating to six big tech companies. I also set up a blog to cross-promote them (but pretty much ignored it after the first couple of weeks).
Here's what happened to follower numbers for the six accounts over the year:There's a generally upward trend, and my Facebook News account (orange) is the most successful, but only acquired a pathetic 50 followers. Google News (green) enjoyed fast growth for about a week about half way through the year, but then fell back again - I don't know what was going on there.
I've had more success with some accounts I've started to cover news of my local area. And I feel more interested in them, which may be a critical difference. But even the tech accounts, to which I subscribe on my personal Twitter account, haven't been a complete waste of time. They aggregate news about companies I like to know about, so just by following them, I learn things I might otherwise have missed.
I suspect other people are having more success with automated Twitter feeds. There is (or was) one for UK media news with a few thousand followers, but I can't find it now.
Here's a report about the New York Times and the Wall Street Journal also coming to the conclusion (albeit on a quite different scale) that you can't really build an audience without some genuine human input: