The question of the meaning of life obviously differs from the also interesting question of the meaning of "life". The latter asks for the meaning of the word "life", while the former asks for the meaning of the thing which is signified by that word. Suppose we take seriously, however, the idea that in asking for the meaning of "life" and in asking for the meaning of life, we are using "meaning" univocally. Then the question presupposes that life, just like "life", is communicative unit. For it is only communicative units that have meaning.
But if life is a communicative unit, then who is communicating to whom? Is it the living person who is communicating, with her life? If so, to whom? Herself? But then living is like talking with oneself, which does not seem right, though I can see that it could be defended. So, maybe, with another. But which other? Presumably either God or fellow human beings (or both). No other options seem available. If only fellow human beings, then if someone is on a desert island and does not expect to meet anybody, her living is just like her talking to the wall—pointless. And that's not right. So, if it is the living person herself who is communicating with her life, she is communicating with God.
Suppose, then, that it is someone else who communicates by means of our lives. There are two options. One is God. The other is society. In the latter case, the life of the person on the desert island, largely formed by desert island experiences, is of questionable meaning.
So if life is a communicative unit, the communication is either by God or with God (or both, a gnostic might add). If so, then the meaning of life does depend on the actual or at least presupposed existence of God.