Comparative Proteomic Profiling of Pancreatic Ductal Adenocarcinoma Cell Lines

Abstract

Pancreatic cancer is one of the most fatal cancers and is associated with limited diagnostic and therapeutic modalities. Currently, gemcitabine is the only effective drug and represents the preferred first-line treatment for chemotherapy. However, a high level of intrinsic or acquired resistance of pancreatic cancer to gemcitabine can contribute to the failure of gemcitabine treatment. To investigate the underlying molecular mechanisms for gemcitabine resistance in pancreatic cancer, we performed label-free quantification of protein expression in intrinsic gemcitabine-resistant and - sensitive human pancreatic adenocarcinoma cell lines using our improved proteomic strategy, combined with filter-aided sample preparation, single-shot liquid chromatography-mass spectrometry, enhanced spectral counting, and a statistical method based on a power law global error model. We identified 1931 proteins and quantified 787 differentially expressed proteins in the BxPC3, PANC-1, and HPDE cell lines. Bioinformatics analysis identified 15 epithelial to mesenchymal transition (EMT) markers and 13 EMT-related proteins that were closely associated with drug resistance were differentially expressed. Interestingly, 8 of these proteins were involved in glutathione and cysteine/methionine metabolism. These results suggest that proteins related to the EMT and glutathione metabolism play important roles in the development of intrinsic gemcitabine resistance by pancreatic cancer cell lines.

Pooled CRISPR screening in pancreatic cancer cells implicates co-repressor complexes as a cause of multiple drug resistance via regulation of epithelial-to-mesenchymal transition

“…This approach was particularly powerful as it leveraged information from 48 experiments (4 drug screens x 3 replicates x 2 cell lines x 2 sgRNAs). We found L2FC sums to be weakly correlated across cell lines (rho=0.014, P=0.034), likely a reflection of strong phenotypic and genetic differences found between our two cell lines (Kim et al, 2014).…”

“…The second general observation was a relatively weak correlation between replicate reproducibility and gene significance levels across cell lines. While this observation may be partially explained by methodological covariates like selection strength ( Figure S4), it is also likely that strong genetic and phenotypic differences observed between these cell lines (Kim et al, 2014) permit different mechanisms of chemoresistance. A gene capable of modulating chemosensitivity across every PDAC cell line would be an ideal target, however, our data suggests that this is not a realistic expectation.…”

Gemcitabine‐induced epithelial‐mesenchymal transition‐like changes sustain chemoresistance of pancreatic cancer cells of mesenchymal‐like phenotype

“…Moreover, chemotherapy or radiotherapy treatments only provide a modest benefit in survival . Previous studies on the intrinsic resistance of different PC cell lines to gemcitabine, distinguished chemosensitive cells with epithelial‐like phenotype from more chemoresistant cells with mesenchymal‐like phenotype . Gene expression profiling showed that spontaneous chemoresistance of the cell lines was associated with low expression of E‐cadherin and high expression of ZEB‐1 .…”

“…27 Previous studies on the intrinsic resistance of different PC cell lines to gemcitabine, distinguished chemosensitive cells with epithelial-like phenotype from more chemoresistant cells with mesenchymal-like phenotype. 28 Gene expression profiling showed that spontaneous chemoresistance of the cell lines was associated with low expression of E-cadherin and high expression of ZEB-1. 29 To investigate acquired resistance mechanisms of PC cells of epithelial-like or mesenchymal-like phenotypes upon sequential chemotherapy regimens, pancreatic tumor cells belonging to these different phenotypes were subjected to a chronic treatment by gemcitabine.…”

Keap1–Nrf2 signalling in pancreatic cancer

“…Nrf2/ARE signalling also controls the expression of cytosolic thioredoxin (TXN1 gene), thioredoxin reductase (TXNRD1 gene), and sulfiredoxin (SRXN1 gene), all of which reduce oxidised protein thiols (Lu and Holmgren, 2014). In PDAC, the glutathione-based antioxidant system contributes to gemcitabine resistance (Kim et al, 2014), and the thioredoxin-based system supports cancer cell survival (Yan et al, 2009).…”