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* Focus on Nvidia results due later in the day

* Palo Alto craters after Q3 billings forecast misses estimates

* SolarEdge slumps on downbeat Q1 revenue forecast

* Futures down: Dow 0.21%, S&P 0.32%, Nasdaq 0.61%

Feb 21 (Reuters) - Wall Street was headed for a lower open on Wednesday ahead of chip designer Nvidia's high-stakes earnings report that could potentially hinder or further fuel this year's AI-led rally, and as investors awaited minutes from the Federal Reserve's latest policy meeting.

Nvidia shed 1.9% in premarket trading after a more than 4% decline in the prior session ahead of the semiconductor firm's quarterly earnings, expected after markets close on Wednesday.

The company is expected to post a more than three-fold surge in its fourth-quarter revenue on robust demand for its chips that dominate the market for artificial intelligence (AI).

Analysts have warned that Nvidia's lofty valuation could make it vulnerable to sharp declines if it delivers anything short of a blowout report and also spark a broader selloff among other technology firms that have benefited from bets on AI.

"(Nvidia) is seen as the lead company in the AI revolution," said Rick Meckler, partner at Cherry Lane Investments in New Jersey.

"With these elevated prices in the megacap tech space, there's clearly nervousness about any level of disappointment. Nvidia really needs to not only beat, but have a very strong forecast for it to reaccelerate to the upside." The chipmaker has jumped 40.2% so far this year, compared with 6.7% and 4.1% year-to-date gains in the Philadelphia Semiconductor Index and the tech-heavy Nasdaq.

The AI-fueled rally on Wall Street this year ran into a rough patch after data last week hinted at sticky inflation and stoked concerns that the Federal Reserve could delay the start of its rate easing cycle.

U.S. stocks ended lower on Tuesday, with the S&P 500 closing below the 5,000-point level.

Minutes from the Fed's January monetary policy meeting, due at 1400 ET (1900 GMT), will offer further clues on the timing of potential interest rate cuts. Investors will also watch out for comments from Atlanta Fed President Raphael Bostic and Fed Board Governor Michelle Bowman on Wednesday.

A majority of traders are currently pricing in June as the starting point for rate easing, compared with March at the start of the year, according to the CME Group's FedWatch tool.

At 08:38 a.m. ET, Dow e-minis were down 81 points, or 0.21%, S&P 500 e-minis were down 15.75 points, or 0.32%, and Nasdaq 100 e-minis were down 107 points, or 0.61%.

Adding to the declines, Palo Alto Networks slumped 24.1% in trading before the bell after the cybersecurity firm forecast third-quarter billings below Wall Street estimates, signaling cautious spending by businesses.

Shares of other cybersecurity companies such as Fortinet , Zscaler and Crowdstrike Holdings fell between 7% and 10%.

Amazon.com gained 0.7%, with the company set to join the Dow Jones Industrial Average effective next week, replacing Walgreens Boots Alliance. Shares of Walgreens slipped 2.8%.

Renewable energy firm SolarEdge Technologies dropped 17.9% after it projected first-quarter revenue below analysts' estimates.

(Reporting by Amruta Khandekar and Bansari Mayur Kamdar; Editing by Shinjini Ganguli)