That is a lot of weight, I hope you know what you're undertaking. MDF is perfectly okay as long as it's built properly. Just remember you need enough support, especially where the doors open at the front. If I was you, I would go and have a good look at Cabinet in one of the shops and see how it is constructed. You're talking to tons of water plus there, you don't want a poorly constructed cabinet folding up underneath all that weight. If you want to do it more expensively and grandly, I suppose you could use oak. Or you could use breeze blocks. However you do it, make sure it's nice and level. Unfortunately, that's about as much advice as I can give you since I've ever built a cabinet before.