To me it seems impossible to use a Canon lens on a Pentax DSLR, although using a Nikkor lens is theoretically possible.
It is a question of flange focal distance (register): Nikon register is longer than Pentax one, Canon register is shorter than Pentax one.
See
Flange focal distance - Wikipedia, the free encyclopedia for more information.
Albeit it is possible to use a Nikkor lens on a Pentax DSLR, you have to keep in mind that automatisms (aperture, focus and so) will be full manual because Nikon-to-Pentax adaptation ring don't provide any automatism.