DR5 agonist antibody surface stabilizes PD‐L1 on solid cancer cells and tumorsA–CTotal PD‐L1, PARP, cleaved caspase‐3 from colon (Colo‐205), lung (A549), pancreatic (PANK1), triple‐negative breast cancer cell (MDA‐MB‐436), and ovarian cell (Cavo‐3) lysates treated with indicated DR5 agonist antib...
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DR5 agonist antibody surface stabilizes PD‐L1 on solid cancer cells and tumorsA–CTotal PD‐L1, PARP, cleaved caspase‐3 from colon (Colo‐205), lung (A549), pancreatic (PANK1), triple‐negative breast cancer cell (MDA‐MB‐436), and ovarian cell (Cavo‐3) lysates treated with indicated DR5 agonist antibodies named Lexa (lexatumumab), KMTR2, BaCa, and tigatuzumab. GAPDH is loading control.DTotal PD‐L1, CD47, Calreticulin, PARP from MDA‐MB‐436 cell lysates treated with indicated DR5 agonist antibodies ± caspase inhibitor Z‐VAD. GAPDH is loading control. See also EV1A for data using additional cell line.ETotal PD‐L1 Western blotting signal from the lysates of OVCAR‐3 (n = 3) and MDA‐MB‐436 (n = 3) cells after 6 h of treatment of 100 nM lexa (DR5 agonist antibody) was normalized to GAPDH. Representative blots are in Appendix S2A.FSurface biotinylation of PD‐L1 from indicated tumor cells after indicated DR5 agonist treatments. Cleaved caspase‐3 and PARP indicate activation of DR5 signaling. In lanes 3 and 4, KMTR2 was pre‐neutralized either with recombinant DR5 (rDR5) or recombinant FOLR1 (rFOLR1). See also EV1B for additional cell line data.GRepresentative flow cytometry plots of PD‐L1 from two different tumor cell lines treated with indicated DR5 antibodies. Secondary alone and IgG1 control are included (See Appendix S1 for additional plots).HRelative surface PD‐L1 % cells, after DR5 agonist treatments (see Appendix Fig S1). Relative signal is normalized to surface PD‐L1 in IgG1‐treated cells in corresponding tumor cells and horizontal line in samples indicated mean (n = 3–4).I0.5 × 106–2 × 106 indicated tumor cells were injected subcutaneously in NOD.Cg‐Prkdcscid Il2rgtm1Wjl/SzJ animals with Matrigel in PBS. When tumors appeared on animals (3–4 weeks), animals were i.p. injected with indicated DR5 agonists (4–6 doses), followed by tumor extraction and preparation of single‐cell suspension isolation from tumors after indicated antibody treatments.JRelative surface PD‐L1 % cells in indicated tumors after DR5 agonist treatments (see Appendix Fig S3). Relative signal is normalized to surface PD‐L1 in IgG1‐treated tumors and horizontal line in samples indicated mean (n = 2–6).KER (−), PR (−), and HER2 (−) UCD52 patient‐derived tumor tissue was xenografted in breast fat pad of NOD.Cg‐Prkdcscid Il2rgtm1Wjl/SzJ mice, following by treatment with IgG1 or KMTR2 (50 μg, four doses). Harvested tumors were analyzed for PD‐L1, CD47, and PARP in lysates.LKMTR2‐treated (50 μg, four doses) UCD52 TNBC PDX tumors were stained for PD‐L1 using immunohistochemistry (IHC). For additional images, see Appendix Fig S2C. Scale bar indicates 50 μm.MTotal PD‐L1 and CD47 blotting analysis from DR5‐resistant MDA‐MB‐436 cell lines after indicated DR5 agonist treatment (50 nM, 6 h). For DR5‐resistant cell generation and additional data, see Fig EV2, EV3, EV4, EV5.Data information: Error bars represent SD. In (E), (H), and (J), unpaired Welch’s t‐test was used to determine P values (*P < 0.05, **P < 0.005, ***P < 0.0001).Source data are available online for this figure.
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