LANSING, Mich. — A letter signed by 120 sexual abuse victims of former sports doctor Larry Nassar on Tuesday urged Michigan State University’s governing board to oust interim president John Engler, saying he has reinforced a “culture of abuse” at the school. The women and girls issued their joint statement three days before the board of trustees’ next meeting and after a week in which demands for Engler’s resignation reached a fever pitch. Engler, who served as the state’s Republican governor from 1991 through 2002, has resisted pressure to step down.