Answer:
Yes, the cube of an integer can be a negative number.
Explanation:
In essence, when we have a number cubed, say x, what we're doing is multiplying such number by itself three times:

Now, let's say that our number is a negative number, in this case -x. Let's take a look at what would happen:

Prooving that, indeed, the cube of an integer can be a negative number.