* TSX down 28.18 points, or 0.18 percent, to 15,772.22
* Seven of the TSX's 10 main groups fell
TORONTO, Oct 12 (Reuters) - Canada's main stock index retreated on Thursday, with declines driven by energy companies that were squeezed by cooling oil prices, as well as a drop in shares of Kirkland Lake Gold KL.TO .
Suncor Energy SU.TO was the biggest drag on the index, falling 1.5 percent to C$42.34. It was followed by Canadian Natural Resources Ltd CNQ.TO , which declined 1.4 percent to C$40.93.
The overall sector retreated 1.3 percent, as oil prices fell amid higher U.S. fuel inventories. U.S. crude CLc1 prices were down 1.8 percent to $50.38 a barrel, while Brent crude LCOc1 lost 1.3 percent to $56.22. O/R influential decliners included Shaw Communications Inc SJRb.TO , which slid 3.2 percent to C$27.63, and Kirkland Lake Gold KL.TO , which slumped 6.1 percent to C$17.37.
Desjardins cut its rating on Kirkland Lake to "hold" from "buy" after the company released quarterly and production results.
The overall materials sector, where miners and other resource companies reside, lost 0.2 percent.
At 10:27 a.m. ET (1427 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE fell 28.18 points, or 0.18 percent, to 15,772.22.
Of the index's 10 main groups, seven were in negative territory.
Financial services stocks slipped 0.2 percent.
On the positive side, Alimentation Couche-Tard ATDb.TO rose 2.4 percent to C$60.37. The company is buying back 4.4 million of its shares that were held by Metro Inc MRU.TO and Eight Capital upgraded the company to a "buy" from "neutral," citing positive trends. The overall consumer staples sector added 0.7 percent. issues outnumbered advancing ones on the TSX by 144 to 94, for a 1.53-to-1 ratio on the downside.