US STOCKS-Wall St opens lower on Greece worries
* Dollar retreats after hitting 12 1/2 yr-high against yen
* Data awaited: April factory orders, May auto sales
* Airline stocks hit by reports of bomb threat
* Dollar General, Cracker Barrel rise after results
* Indexes down: Dow 0.47 pct, S&P 0.47 pct, Nasdaq 0.53 pct (Updates to open)
By Tanya Agrawal
June 2 (Reuters) - U.S. stocks opened lower on Tuesday lower amid uncertainty over the outcome of Greece's negotiations with creditors and ahead of data that could point to the timing of a U.S. rate hike.
Data due on Tuesday includes April factory orders at 10:00 a.m. ET (1400 GMT). Demand for manufactured goods is likely to have been flat after a strong showing in March.
The auto industry will report sales for May and analysts expect demand to have been flat or down slightly from last year. Continuación...