Rachel Maddow, Andrea Mitchell and Maria Shriver are among a group of 65 women in the US television industry who circulated a letter in support of the longtime NBC anchor Tom Brokaw, after he was accused by a former colleague of unwanted sexual advances.

Brokaw, who denies the accusations, complained in an email to friends of being “ambushed and then perp walked across the pages of the Washington Post and Variety as an avatar of male misogyny, taken to the guillotine and stripped of any honor and achievement I had earned in more than a half century of journalism and citizenship”.

Kelly O’Donnell, Anne Thompson and Kristen Welker also put their names to the group letter, in which the women say Brokaw, 78, has treated all of them with fairness and respect, giving them opportunities for advancement and championing successes in their careers.

Brokaw, the letter says, is “a man of tremendous decency and integrity”.

The letter was first reported in the Hollywood Reporter and confirmed by the Associated Press.

In an email written at 4am and sent to friends Brokaw, a former NBC Nightly News anchor, reacted angrily to charges that he made unwanted sexual advances to Linda Vester two decades ago.

Brokaw wrote that Vester failed in her pursuit of stardom and was given media space to vent her grievances. Vester, who worked as a war correspondent for NBC News, told the Post and Variety Brokaw groped her and tried to forcibly kiss her in the 1990s.

Brokaw wrote that he was “angry, hurt and unmoored from what I thought would be the final passage of my life and career”.

On Friday, Sacred Heart University in Connecticut said Brokaw had notified school officials he would not deliver its commencement speech as planned on 13 May. Brokaw will be replaced by Linda McMahon, head of the Small Business Administration under Donald Trump. McMahon is a school donor and has been on the Catholic university’s governing board.