Can international students in USA intern in summer in industry?
Yes you can, and this is exactly what CPT is for. (assuming you get paid for the internship. If you are not being paid - I'm not sure what the rules are, but it might be easier than CPT)

You can do it for up to 12 month (not necessarily consecutive) during your degree. Check again with your international Office for the exact rules (you might still need to be enrolled to 12 units if not summer quarter/semester).