Troubles with emails started with "-"(dash)

We have Ruby On Rails application with some emails subscription. It has mailer class inherited from ActionMailer:

class UserMailer < ActionMailer::Base
...
end

Everything ok, except one thing - some users have email addresses with "-" at begin. It occur errors when I'm trying send email to "-user@mailinator.com":

sendmail: invalid option -- u
sendmail: invalid option -- s
sendmail: invalid option -- u
sendmail: fatal: usage: sendmail [options]

How could I escape this character(and maybe some similar) for ActionMailer?

Thanks