Fig 2: Working model for Impad1 modulation of Golgi morphology and vesicular trafficking to drive invasion and metastasisLoss of the epithelial miRNAs miR-200 and miR~96 de-represses Impad1 during EMT. In mesenchymal cells, Impad1 promotes Golgi stacking and condensation as wel as vesicular trafficking in an epistatic pathway with Syt11 to enhance exocytosis of extracellular components such as MMPs, collagen, and GAGs. This increased secretion alters the ECM and TME to drive lung cancer invasion and metastasis.

Fig 3: Syt11 is necessary to drive Impad1-mediated exocytosis, invasion, and metastasis in lung cancer(A) VSV-G assay confocal images of 393P Impad1-overexpressing cells co-transfected with EGFP-VSV-G and siControl or siSyt11. Green, total VSV-G; red, surface VSV-G. Scatterplots (right) show the ratio of surface to total VSV-G signal intensity/cell. n = 20; statistical outliers were removed. Each experiment had 3 technical replicates and 2 biological replicates. Scale bars, 10 µm.(B) mRNA and protein confirmation of siRNA-mediated knockdown of Syt11 in 344SQ Impad1-overexpressing cells.(C and D) Boyden chamber assay quantifying cell invasion upon siSyt11 in 344SQ vector or Impad1-overexpressing cells. Scale bars, 100 µm.(D) Boyden chamber assay quantifying invasion in 344SQ control or shSyt11 cells. Scale bars, 100 µm.(E) Secretome-mediated invasion assay quantifying invasiveness of 393P KP cells replenished with conditioned medium (CM) from 344SQ scramble and shSyt11 cells. Scale bars, 100 µm.(F) Western blot analysis of MMP1 and MMP2 in CM collected from 344SQ scramble and shSyt11 cells. Densitometric analysis of the blots was performed using ImageJ.(G) 344SQ cells with stable Syt11 knockdown form significantly fewer lung metastatic nodules compared with the scramble control.(H) Masson trichrome staining detecting collagen (blue) in 344SQ control and Syt11 knockdown syngeneic tumors. Scale bars, 50 µm.See also Figure S6. Data represented as mean ± SD. Significance by Student’s t test. *p < 0.05; **p < 0.002.