Figure 6.

HER2 expression is significantly correlated with PD-L1 expression in gastric cancer tissues. Brightfield images showing morphological differences among huTGOs derived from intestinal (a,e) and diffuse (i,m) subtypes of gastric cancer tissues. Immunofluorescence staining of these organoids showed a high expression of (b–d,j–l) HER2 (red) and PD-L1 (green) in two of the organoid lines while others showed a negative expression (f–h,n–p) for both. Western blot (v) analysis of gastric cancer tissues showed a similar expression pattern. (q) shRNA knockdown of HER2 showed a downregulation of PD-L1 expression which was confirmed by (u) Western blot analysis and quantification. (r,s) Quantification of HER2 and PD-L1 positive cells showed a significant reduction in the expression of both genes after HER2 shRNA knockdown; * p < 0.0001. (t) Linear regression analysis showing a positive correlation of HER2 and PD-L1; Immunohistochemistry of PD-L1 (w) and HER2 (x) retained high expression levels among gastric cancer tissues, tissue-derived organoids and orthotopically transplanted organoids. Scale bar = 100 μm and 50 μm.