Well these two are quite alike in a sense of taking the risk, and gambling your profit. You are betting here in a sense of expecting a later on profit. The two are executed differently but if we look upon on deeper context the two lies on a same mean. Trading taking the risk time after time when to buy and sell in a hope of profit, while, gambling games are simply betting in and let the luck be in your favor while taking the risk. What I mean to say is that the two are similar in a sense of taking the risk, and taking the gamble whether to gain profit or not.
You could lost in trading though but you could prevent in a sense of proper monitoring and time of selling. But still there are risk involve and gamble which may also imply to casinos.