* TSX falls 26.84 points, or 0.20 percent, to 13,353.57 * Six of 10 main index sectors decline * Canadian Natural, Tim Hortons gain after results By John Tilak TORONTO, Nov 7 (Reuters) - Canada's main stock index retreated on Thursday after the European Central Bank trimmed interest rates, weighing on commodity prices and natural resource stocks. Investors also processed mixed data that showed U.S. economic growth accelerating in the third quarter but consumer spending expanding at the slowest rate in two years. The ECB, which cut interest rates to a new record low, said it would prime banks with liquidity into 2015 to prevent the euro zone's recovery from stalling as inflation tumbles. "The reduction of interest rates by the ECB surprised everyone," said John Ing, president of Maison Placements Canada. "It reminds investors that we're still in very uncertain territory," he said. The Toronto Stock Exchange's S&P/TSX composite index was down 26.84 points, or 0.20 percent, at 13,353.57. Six of the 10 main sectors on the index were in the red. Shares of energy companies led the decline, falling more than 1 percent, as oil prices dropped. Suncor Energy Inc gave back 1.5 percent to C$36.13, and Encana Corp dropped 2.1 percent to C$19.03. But the losses were somewhat capped by a 1.3 percent jump in Canadian Natural Resources Ltd after the oil producer's third-quarter profit more than tripled as a result of record quarterly production and strong oil prices. Two of Canada's top retailers also posted results. Tim Hortons Inc reported an 8 percent rise in quarterly profit as same-store sales improved slightly in the United States, pushing its shares up 0.4 percent to C$62.83. [ID: nL3N0IS4EM] Canadian Tire Corp Ltd recorded a stronger-than-expected 11 percent rise in quarterly profit. The stock was down slightly.