1. Harvest cell culture medium from 80% confluent cells grown in serum-free medium. 2. Spin media at 500-1,000 x g for 10 min (optional), pre-clear by centrifuging at 2000 x g for 10 min, filter with 0.22 µm PES membrane, freeze at -80°C. 3. Thaw 4 ml supernatant on ice, add 4 ml XBP buffer, mix by inverting 5 times. 4. Add sample/XBP mix to exoEasy maxi spin column, centrifuge 1-3 min at 500 x g, discard flow-through. 5. Add 10 ml XWP to spin column, centrifuge 5 min at 5,000 x g, transfer column to fresh collection tube. 6. Add 700 µL Qiazol to spin column, centrifuge 5 min at 5,000 x g, spin PLG tubes 30 s at 16,000 x g. 7. Add flow-through to PLG tube, vortex 5 s, incubate 5 min at RT. 8. Add 90 µL chloroform, shake vigorously for 15 s, incubate 2-3 min at RT. 9. Centrifuge 15 min at 12,000 x g, transfer upper aqueous phase to new tube, add 2 volumes 100% ethanol, mix. 10. Add mix to MinElute spin column, centrifuge 15 s at 1,000 x g, discard flow-through, repeat until all sample is used. 11. Wash column with 700 µL Buffer RWT, centrifuge 15 s at ≥8,000 x g, discard flow-through. 12. Wash twice with 500 µL Buffer RPE, centrifuge 15 s and 2 min at ≥8,000 x g, discard flow-through. 13. Transfer column to new 2 ml tube, dry membrane by centrifuging at full speed for 5 min, transfer to new 1.5 ml tube, add RNase-free water, centrifuge to elute RNA.