No. If you have processed I-485 after I-140 has been approved , you could have received GC by now and could have joined any other company. Since I-140 is valid as long as you have maintained job with that company who sponsored you but I did not get why you did not you file for I-485 or may be you are hiding something here.
So the answer is: Once you leave that company and joined other company, your GC process ends there itself and you have file again through new company sponsor. To let you know that GC is not portable from one company to another. Why do not you file again ? Consult with an experienced immigration lawyer (get opinion at least from two lawyers ) and decide. Hope that helps you.