Abstract 1539: Analysis of differential protein profiles in co-culture models of pancreatic cancer cells and fibroblasts
Authors: Prieto-García Elena , Agulló-Ortuño M. Teresa , Díaz-García C. Vanesa , García-Consuegra Inés , Adeva Jorge , Riesco M. Carmen , Parrilla Lucía , Gómez Carlos , Lema Laura , Robles Luis , Cortés-Funes Hernán , López-Martín José A. 
Published: August 2015

Background: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal human malignancies. The vast majority of patients with advanced disease die within a year of diagnosis.

Tumor microenvironment plays a critical role in tumor initiation, progression, metastasis, and response to treatment in PDAC. Pancreatic adenocarcinoma cells often appear to grow within a fibrotic, abundant, and poorly perfused stroma, with epithelial cells frequently accounting for &lt;20% of the tumor volume. Cellular components of tumor stroma include fibroblasts, macrophages, and stellate cells plus extracellular proteins. Moreover, the network of tumor stroma imposes a barrier for drug delivery.

The aim of this study was to search for novel protein biomarkers of tumor-stroma interaction for a better understanding and intervention of PDAC.

Methods: 1- Co-cultures between two pancreatic adenocarcinoma cell lines (PL45 and Capan-1) and embryonic fibroblasts (LC5) were established. LC5 cell line was stably transfected with Green Fluorescent Protein (GFP) to allow their detection, and later separation by flow cytometry, of the co-cultures. 2- In addition, tumor cells were grown with fibroblasts secretome. 3- After 72 hours of co-culture, tumor cells were isolated and protein extraction was performed. 4- Proteins differentially expressed in tumor cells grown in co-cultures, or in tumor cells grown with fibroblasts secretome, versus in tumor cells monocultures, were identified by using two-dimensional electrophoresis-based proteomic tools (2D-DIGE) followed by mass spectrometry (MS/MS) of the spots of interest.

Results: A total of 105 differentially expressed proteins were documented between PL45 cells growing in mono-culture, co-culture and conditioned medium. Also, 161 differentially expressed proteins were recognized under similar conditions in the Capan1 cell line.

Our study identified seventeen different proteins mainly involved in cytoskeleton organization (Filamin B, Alpha-actinin-4, Annexin A2, Radixin, T-complex protein 1 subunit epsilon, Actin cytoplasmic 1); regulation of cell migration and adhesion (Prelamin-A/C, 40S ribosomal protein SA); protein biosynthesis (EF-2); DNA damage and repair response (VCP, XRCC6); nucleotide biosynthetic process (MTHFD1) and, heat-stress response (HSPD1, GRP78, STIP1, CCT5, Stress-70 protein mitochondrial).

Conclusion: This in vitro model identifies several processes that might be responsible for the tumor-stromal interactions occurring in vivo, which should be considered potential targets for therapeutic interventions in PDAC, in addition to those targets already known to exist in PDAC cells.

Citation Format: Elena Prieto-García, M. Teresa Agulló-Ortuño, C. Vanesa Díaz-García, Inés García-Consuegra, Jorge Adeva, M. Carmen Riesco, Lucía Parrilla, Carlos Gómez, Laura Lema, Luis Robles, Hernán Cortés-Funes, José A. López-Martín. Analysis of differential protein profiles in co-culture models of pancreatic cancer cells and fibroblasts. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1539. doi:10.1158/1538-7445.AM2015-1539