NEW YORK ( TheStreet) -- News from Europe, particularly Greece, is driving the market Thursday. The uncertainty about debt-laden Greece has ruled the headlines for months now, and the nervousness about a potential default hasn't subsided. But U.S. stock futures were rising slightly after European leaders put their foot down, saying a plan in Greece to hold a referendum on the European bailout plan would determine whether Greece remains a part of the eurozone. Voting on the referendum is expected to take early next month. European stocks turned higher after posting losses earlier in the day on word of an emergency cabinet meeting in Greece. European leaders are holding another round of emergency meetings about Greece on Thursday. President Obama, in France for the G20 summit, stressed the importance of reaching a resolution on the financial crisis in Europe. "We're going to have to flesh out more of the details about how the plan will be fully and decisively implemented," Obama said. Obama didn't say what the U.S. might do to help European officials solve the crisis in Greece. Occupy Wall Street protesters shut down the Port of Oakland, the nation's fifth-busiest shipping port, late Wednesday. Reports said protestors and the police clashed downtown early Thursday following Wednesday's largely peaceful protests throughout Oakland. The Occupy Wall Street movement began in New York in September. GlaxoSmithKline ( GSK) agreed in principle with the U.S. government on a $3 billion settlement of investigations over the U.K. drugmaker's sales and marketing practices. The agreement is expected to be completed in 2012. GlaxoSmithKline said the settlement would be paid through its cash resources. The case includes a Department of Justice investigation into the marketing of GlaxoSmithKline's diabetes drug Avandia. Expect Dendreon ( DNDN) to open sharply lower Thursday following a disappointing third-quarter earnings report in which management forecast lower Provenge sales for the rest of the year. Provenge sales totaled $64 million in the September quarter, slightly ahead of consensus, but higher-than-expected costs plus a lackluster outlook for the fourth quarter sent Dendreon shares down as much as 22% in after-hours trading. Enduro Royalty 's ( NDRO) initial public offering priced at $22 on Wednesday, below the expected range of $23-25. -- Written by Joseph Woelfel >To contact the writer of this article, click here: Joseph Woelfel >To submit a news tip, send an email to: firstname.lastname@example.org.