March 4 (Reuters) - Royal Bank of Canada RY.TO cut the prime rate for Canadian borrowers to 3.45% from 3.95% on Wednesday, the first reduction since July 2015, kicking off a raft of expected cuts in response to the Bank of Canada's 50-basis-point interest rate cut. other banks are expected to follow suit. The lenders in 2018 incorporated into their prime rates the full extent of the central bank's three interest rate increases.