Adsense is through google. Did you set up any other security features when you set up your google account? Like security questions or a mobile phone number.
Go to google, go to the sign in area, then click links to lost password and any others. Try them all until you can find other other security options besides needing your email address, if there are any.
If there are none, and you do not know your security questions or the mobile you used on your account, you may be stuck.
I would recommend always keeping a record of the email addresses and other things you set up online accounts with.
Worst option may be to set up a new google account, and then associate your hubpages with the new Adsense account and the same one with YouTube and any other sites you use