U.S. stock-index futures signaled a lower open on Friday, after the first estimate of how much the U.S. economy grew in the final quarter of 2014 and more fourth-quarter earnings reports.The fourth-quarter GDP estimate The Chicago Purchasing Managers’ Index is due at 9:45 a.m. Eastern, followed by the final reading of the University of Michigan’s consumer sentiment survey for January, which should confirm the multi-year high indicated by the earlier reading. Eli Lilly became the latest company citing foreign-exchange pressures, as it reported that its fourth-quarter earnings suffered from the impact of patent expiration of some of its key drugs.Lilly posted earnings of $ 428.5 million or 40 cents a share, down from $ 727.5 million or 67 cents a share in the prior-year period. Wall Street is on track to end the first month of the year with losses , as investors reassess the impact on companies from the decline in energy costs, a stronger U.S. dollar and a weaker global economy. European markets were mixed on Friday after official statistics showed the euro zone slid further into deflation in January. On Friday, the central bank of Russia cut its key interest to 15 percent-after hiking rates to 17 percent just on month ago.

Read More Russia extends olive branch to Greeks Speaking to CNBC on Thursday, the Russian finance minister said that Moscow would consider giving financial help to debt-ridden Greece-just days after the new Greek government questioned further European Union sanctions against Russia.