It's a Dog's Life (1992)

Bull terrier Wildfire roams the streets of New York City's Bowery district bent on killing his father, who abandoned him and his mother. But when his mother vanishes, the dog is forced to brave the hard streets alone. That is, until he becomes the possession of a ne'er-do-well, Patch (Jeff Richards), who trains him to be a fighting dog. He gets a chance for a better life, though, when he lands a home with a wealthy family and eventually wins prestigious dog shows, becoming the toast of the city.