Help Late Night Cat

Help, My boyfriend and I adopted a Cat a year ago and up to recently everything has been good. However for the last two months she has started meowing at 4am in the morning, every night at first we thought it may have been due to the fact that we were both working long hours and She was not getting enough attention, however she now gets a minimum of 1 hour play each night and still it goes on.
We have tried locking her out of the bedroom, but she gets louder and scratches the door, at wits end so would love some help

Did you get up with her when the behaviour started? Cats are very quick learners and it only takes one time of giving in for them to figure out they get what they want if they scream at you enough. Do you know what it is that she wants - food, play, snuggles? (If she just wants snuggles and love, you can do that almost in your sleep - I do that with my kitty!)

As for stopping the early morning wake up calls, get some good ear plugs and ignore her. Even getting up to kick her out of the bedroom is showing her that she got some response, even if it's not the one she wanted. They don't give up easily, but she will eventually learn that screaming at you won't get her what she wants.

What she said. (Seriously, I can't think of anything else. Sorry.)
HMMMM__ I had a cat who liked to sit on the windowsill while I was sleeping and unexpectedly jump down on the bed. That awakened me, so any time she got on the windowsill, I shook my finger and said sternly, "No jumping!" Then if she jumped, I did the same thing, only louder, because I REALLY meant it. She caught on, but it took time. They don't like loud noises.

I have learned to sleep through it. I sleep with earplugs and just roll over when one of them jumps on me. Fred has jumped on me every morning promptly at 7:30 am for the past 10 years.