Fig. 1: Effect of chemo–immunotherapy combination on KRAS/LKB1 mutant lung metastasis in humanized mice.

a NSG mice were humanized through human CD34⁺ stem cells implantation into irradiated mice and the level of reconstitution of human immune cells into mice system after 5 weeks of post-humanization is shown. b Human HLA typing results of both HLA-A and HLA-B locus of umbilical cord blood donors. c Expression level of MHC class I and II on KRAS/LKB1 mutant cancer cell line. The level of expression of MHC I and MHC II on A549 was determined based on the expression level on PBMCs, which is used as a positive control in the experiment. d Scatter plot analysis to show the level of major human immune cells in humanized mice. A hundred microliters of blood collected from tail vein and immune cells were stained and analyzed by flow cytometry. e Treatment strategy where 7–8 weeks post humanized mice were implanted with tumor and lung metastases were treated with carboplatin (10 mg/kg) every other day (purple arrow) for 2 weeks and pembrolizumab (250 ug/mouse) every 3–4 days for 3X (green arrow). f Small animal imaging was done by IVIS 200 to determine the bioluminescence signal from tumor cells at week 2. g, h Quantitative analysis of tumor intensity determined from IVIS imaging at week 2 and week 3 respectively. i IVIS imaging of tumor-bearing humanized mice in different treatment groups at week 3. j Tumor growth curve shows the growth of lung metastasis and the response to the treatment at different time points. k Tumor growth curve comparison between carboplatin alone and carboplatin + pembrolizumab combination treatment groups at extended time points. The results shown are from one of three independent experiments with similar results; bars, SD. *P < 0.05, **P < 0.005, ***P < 0.0005.