Fig. 4: Preferential XPAT protein unmasking in tumor tissue.
a, Fluorescent dye-labeled HER2-XPAT or EpCAM-XPAT protein was used to track proteolytic cleavage in PDX tumor-bearing mice. b, A representative SDS–PAGE gel showing XPAT protein cleavage forms arising in a single PDX-bearing mouse, after imaging by LI-COR Biosciences. Four bands representing HER2-XPAT protein and its three unmasked forms are visible in the tumor sample (green channel) while the other (red channel) predominantly shows the XPAT protein form. c, Concentration of XPAT protein forms in tumors and healthy tissues. Results are the mean ± s.d. from 20 mice within one single experiment, with tumors consisting of ten different PDX (Supplementary Table 3); mice were injected with fluorescent dye-labeled HER2-XPAT or EpCAM-XPAT protein. Note that tissues for which ≥14 samples were below the limit of quantification (BLQ) were reported as ‘BLQ.’ Tissues with averages calculated using some samples with BLQ readings are marked with an asterisk.
