CANNES: Vampires, Transformers, singing high-schoolers: They can all be tough to outrun.   But at the 65th annual Cannes Film Festival, a number of young Hollywood stars are attempting to do just that. By striking out on their own, they hope to move their careers beyond mega franchises and toward more mature roles in bolder films.     

Robert Pattinson (''Twilight''), Kristen Stewart (also ''Twilight''), Shia LaBeouf (''Transformers,'' ''Indiana Jones and the Kingdom of the Crystal Skull'') and Zac Efron (“High School Musical'') all have films in competition at the French Riviera festival.

In David Cronenberg's Don DeLillo adaptation ''Cosmopolis,'' which is to premiere at Cannes on Friday, Pattinson stars as a Manhattan billionaire on a crosstown odyssey.

''It's changed the way I see myself,'' Pattinson said in an interview ahead of his festival arrival. ''I'm kind of getting older,'' the 26-year-old actor says. ''People aren't thinking of me as a kid anymore, so I've got to stop behaving like one.''

With the next ''Twilight'' installment, part two of ''Breaking Dawn,'' due out this November, Pattinson has also lined up parts in David Michod's ''The Rover'' (a role he says he fought harder for than any in years) and the military thriller ''Mission: Black List.'' Like ''Cosmopolis,'' they're films without the surrounding hoopla of blockbusters.

''When you do a big franchise movie, there's a ton of pressure on you that's really nothing to do with the job at all,'' says Pattinson. ''You have to adapt to an entirely different world, rather than just try to get better at acting and do better within your movies. As soon as you become famous, your movies and your life become one and the same in the eyes of the public in a lot of ways.''

Certainly, most actors would eagerly jump at the chance to star in well-paying, hugely promoted movies. But iconic roles begun as teenagers can choke promising acting careers. Stewart, Pattinson's 22-year-old ''Twilight'' co-star, is also expanding into new territory at Cannes with Walter Salles' anticipated adaptation of Jack Kerouac's ''On the Road.'' It was to premiere Wednesday.

Earlier in the festival was LaBeouf's ''Lawless,'' a Prohibition-era gangster film. LaBeouf says he's gratified to have been a part of the film from start to finish, rather than, he says, ''just piggybacking'' on the success of a massive blockbuster. LaBeouf, who also stars in Robert Redford's next film, ''The Company You Keep,'' hopes ''Lawless'' is the start of a new phase for him.

''I'm taking risks more,'' says LaBeouf, who play the youngest in a trio of Virginia bootleggers in ''Lawless.'' ''I was really risk-adverse for a while because I had a big nugget to protect, not only for myself but for the people who were behind me. I think I've become less corporate.''         ''Lawless'' director John Hillcoat says LaBeouf, 25, ''has been a prisoner of the franchise films for a while.''

''He was so hungry for a real character, a real part,'' says Hillcoat.

On Thursday, Lee Daniels will bring his ''The Paperboy'' to the festival, the director's first film since the hit ''Precious: Based on the Novel 'Push' by Sapphire.'' Efron, 24, co-stars as the younger brother of a reporter (Matthew McConaughey) who's investigating an inmate on death row (John Cusack).

Daniels says that having suffered relentless viewings of the ''High School Musical'' movies by his children, he thought he'd never put Efron in one of his movies. ''And I can't tell you how wrong I was,'' he says.

The Efron of ''The Paperboy,'' Daniels says, is one unfamiliar to his fans.

''He's a grown-up Zac and a tortured Zac,'' says Daniels. ''Someone we haven't seen before  a different Zac.''

Efron, Stewart, LaBeouf and Pattinson will get no better launching pad for their new roles than Cannes, where daring is prized above all other attributes. ''There's no point in being scared of just trying,'' says Pattinson. ''The worst that can happen is just failure, right?''