BOSTON—One of five Russian nationals who authorities allege made tens of millions of dollars in illegal profits by trading shares of companies using information stolen during hacks of U.S. computer networks has been extradited to the U.S. to answer to the charges, federal prosecutors in Boston announced Monday. Vladislav Klyushin, 41, whose last name is sometimes spelled Kliushin, was arrested in Sion, Switzerland, on March 21 and was extradited to the U.S. on Dec. 18, acting U.S. Attorney for Massachusetts Nathaniel Mendell said. “In simple terms, they hacked into U.S. networks, stole inside information, and cheated honest investors out of millions of dollars,’’ Mendell said at a news conference. No defense attorney was listed for Klyushin in online court records. According to the U.S. Securities and Exchange Commission, which filed parallel fraud charges against the defendants Monday, they made a total of $82 million through the scheme from 2018 through …