Originally posted by JakeTheBank
Given that the enchantment hasn't foiled other mystical items such as Mjolnir and the lasso effected beings such as Ares, a Hecate-amped Circe, and Final Crisis Darkseid, it's more likely that the lasso would effect him than it wouldn't.
On the other hand though, Colossus' unique metal has been shown as directly resisting or outright ignoring hostile magical influences against him. The lasso may not work as it's supposed to or work at all.