I'm afraid I'm not much help, because though I buy and use a ton of metallic accented fabrics, I've never had any problem because of them. I used a regular 80/12 quilting needle with 40wt cotton thread in the top and bobbin. I had significant trouble with my last quilt because I was in a hurry and couldn't wait for the elmer's to dry, so I spray basted instead and that caused so much gunk on my needle and I broke threads constantly. Horrible. Did you change anything about how you basted? What are you using on the back?
As I reread your post again, do you mean that the actual metallic portion of the fabric you're quilting is breaking? On first read, I thought you meant the top thread was breaking.