Differential expression of MTCBP-1 and MT1-MMP in human tumors. (A) Western blot analysis of MT1-MMP and MTCBP-1 protein levels in nine different PDAC cell lines showing a trend of reciprocal expression. (B) Western blot analysis of total MT1-MMP protein level in Panc-1 cells following depletion of MTCBP-1 by siRNA treatment. Quantification shows an increase of MT1-MMP protein level upon MTCBP-1 depletion. Graph represents normalized averages ± SEM from three independent experiments. *, P < 0.05. (C) IHC staining of MTCBP-1 and MT1-MMP in serial sections of tissues from pancreatic cancer patients, including normal adjacent pancreas (Benign), PDAC, and metastases from lymph nodes (Mets). Boxed areas are magnified in insets. Bars, 10 µm. (D) Semi-quantification of IHC staining of MTCBP-1 and MT1-MMP in pancreatic ductal cells from 10 different patients, showing the expression level of MTCBP-1 and MT1-MMP are increased in primary lesions and metastases. Note that the expression level of MTCBP-1 in metastases is lower than that in the primary tumor. (E and F) Kaplan–Meier curves demonstrating the relationship between patient survival and MTCBP-1 expression level in PDAC patients. High MTCBP-1 expression is associated with better overall survival in two cohorts, including the GSE21501 dataset (E) and TCGA dataset (F). All blot measurements in kD.