If you can match the section properties of the box section with the C-section to resist in the direction of loading, then yes...with two cautions...
1. The weak direction bending strength will likely be less
2. The C-section will likely have lower torsional resistance
Assuming from the basic nature of your query that you are not familiar with structural analysis, I would suggest that you get a structural engineer involved. Further, you are only considering loading in one direction...there are likely more considerations that need to be made.