* TSX down 50.14 points, or 0.4 percent, at 12,415.98 * Index posts 1.75 percent gain for the week * Nine of the 10 main groups lower on Friday * Astral Media shares plunge 15.94 percent to C$39.51 By Solarina Ho TORONTO, Oct 19 (Reuters) - Canada's main stock index finished lower on Friday, breaking a four-day winning streak, as shares of Astral Media Inc plunged almost 16 percent after the country's broadcast regulator blocked its planned takeover by BCE Inc. Negative sentiment from quarterly U.S. corporate results also spilled into Canadian stocks as earnings from bellwether companies disappointed investors already concerned about global growth and Europe's debt crisis. "A bit of this end-of-the-week sell-off is some disappointment around earnings from some companies within the S&P 500 and the Dow," said Craig Fehr, Canadian market strategist at Edward Jones in St. Louis, Missouri. Earnings are "really reflecting the pressure that corporate profits are under right now given the broader economic backdrop," he said. Multiple analysts cut their price targets for Astral Media after the Canadian Radio-Television and Telecommunications Commission blocked BCE's C$3 billion ($3.05 billion) bid. Astral was one of the most influential decliners on the index, with its shares falling to C$39.51. BCE fell 1.76 percent to C$42.86, while the overall telecoms sector was off 0.33 percent. The consumer discretionary sector, home to Astral and other media companies, was down 1.26 percent. Corus Entertainment shed 2.83 percent to C$22.33. "Obviously there were a lot of people who were disappointed that this deal didn't go through," said Fred Ketchen, director of equity trading at ScotiaMcLeod. "BCE is certainly a significant weight within the index. ... It does have a bearing on sentiment, it does have a bearing on the market." The CRTC said the deal would give too much power to BCE, already Canada's biggest telecoms company. It was the biggest deal the commission has ever blocked, marking a shift toward consumer advocacy. The Toronto Stock Exchange's S&P/TSX composite index gave back 50.14 points, or 0.4 percent to finish at 12,415.98. Nine of the index's 10 main groups were lower. For the week, the index posted a 1.75 percent gain. "We started the week with a host of much better-than-expected economic data. ... It set a positive tone for the week in terms of investors feeling a little better about the trajectory of the North American economy," said Fehr. Materials, home to mining companies, was the lone gainer and was up 0.26 percent, bolstered primarily by gold mining firms, which bounced back from a 2.42 percent drop on Thursday. Goldcorp was up 2.01 percent at C$43.05, while Yamana Gold Inc climbed 1.48 percent to C$19.23. Seven of the 10 most influential advancers were gold companies. Also dragging on the index were technology stocks, which fell 1.36 percent, in reaction to weaker-than-expected results from Google Inc and Microsoft Corp. The heavily weighted energy group shed 0.53 percent, while the financial group gave back 0.38 percent. Fehr said lingering worries in Europe also weighed. "Our expectation as we progress through the year and for some time to come is Europe is going to continue to have spates of volatility. ... I think we're getting a little bit of that today following on the less optimistic corporate profit news," he said.