If you do not set the Google Cache control you are actually using it:
NOTE: By default, publicly readable objects are served with a Cache-Control header allowing such objects to be cached for 3600 seconds.
If you need to ensure that updates become visible immediately, you should set a Cache-Control header of
"Cache-Control:private, max-age=0, no-transform" on such objects. You can do this with the command:
gsutil setmeta -h "Content-Type:text/html" \
-h "Cache-Control:private, max-age=0, no-transform" gs://bucket/*.html
Therefore I think it is not possible to disable the caching without changing the Google cache-control, however notice that Cache-Control only applies to objects with a public-read ACL, non-public data are not cache-able.
Note also that because objects can be cached in different places on the Internet, that can ignore metadata and act as they prefer, there is no way to force a cached object to expire globally (in the same way you can force your browser to refresh its cache).
Can you explain better why you want to avoid to use it?