(F) Surface biotinylation of PD-L1 from indicated tumor cells after indicated DR5 agonist treatments. Cleaved caspase-3 and PARP indicates activation of DR5 signaling. In lane 3 and 4, KMTR2 was pre-neutralized either with recombinant DR5 (rDR5) or recombinant FOLR1 (rFOLR1). 