Aug 26 (Reuters) - The S&P 500 and Nasdaq opened slightly lower on Thursday as mixed earnings reports and economic data kept investors on the edge ahead of the Federal Reserve’s Jackson Hole policy summit. The Dow Jones Industrial Average rose 44.2 points, or 0.12%, at the open to 35,449.68. The S&P 500 fell 2.4 points, or 0.05%, to 4493.75, while the Nasdaq Composite dropped 16.7 points, or 0.11%, to 15,025.166 at the opening bell. (Reporting by Sruthi Shankar in Bengaluru; Editing by Shailesh Kuber) Our Standards: The Thomson Reuters Trust Principles.