EACR25-2036

Enhancing Therapeutic Efficacy in Patient-Derived Models of Pancreatic Ductal Adenocarcinoma Using Engineered Placental Mesenchymal Stromal Cells

V. Buocikova¹, L. Drndakova¹, M. Burikova¹, Z. Kozovska¹, U. Altanerova², J. Jakubechova², M. Andrezal², D. Vanova², B. Smolkova³, C. Altaner^1,2

¹Biomedical Research Center of the Slovak Academy of Sciences, Cancer Research Institute, Bratislava, Slovakia
²St. Elisabeth Cancer Institute, Stem Cell Preparation Department, Bratislava, Slovakia
³Biomedical Research Center of the Slovak Academy of Sciences, Cancer Research Institute;, Bratislava, Slovakia

Introduction:

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer exhibiting a dismal five-year survival rate of less than 10%. A major obstacle in the PDAC treatment is a dense stromal environment, primarily regulated by cancer-associated fibroblasts (CAFs), the most abundant cell type in PDAC stroma. Our study aimed to develop engineered extracellular vesicles (EVs) derived from transduced placental mesenchymal stromal cells (PlacMSCs), carrying mRNA encoding the yeast cytosine deaminase::uracil phosphoribosyl transferase (yCD::UPRT) fusion gene, converting the non-toxic prodrug 5-fluorocytosine (5-FC) into the cytotoxic agent 5-fluorouracil. Furthermore, the influence of CAFs on therapeutic response was evaluated to improve the reliability of the organoid model.

Material and method:

Conditioned media from PlacMSCs transduced with yCD::UPRT was concentrated (yCD::UPRT-PlacMSC-cCM) using a tangential flow filtration system (TFF-Easy, HansaBioMed Life Sciences) and EVs characterized by Nanoparticle Tracking Analysis (NTA) using NanoSight NS500 Instrument (Malvern Instruments Ltd.). The organoids (PDXOs) were generated from subcutaneous patient-derived xenografts (PDXs). Donor patient tumors and corresponding PDXOs were characterized by immunohistochemical analysis (IHC). Besides, the therapeutic effect of yCD::UPRT-PlacMSC-cCM + 5-FC was determined on patient-derived CAF primocultures (CAF31, CAF78, CAF79) and PDXOs (PDXO71 and PDXO113) by CellTiter-Glo® Luminescent/3D Cell Viability Assay (Promega Corporation). Finally, the biological activity of yCD::UPRT-PlacMSC-cCM was assessed on the cocultivation model of CAF31 and both PDXO samples.

Result and discussion:

NTA detected particles in concentrations between 7.8x109/mL and 9.6x109/mL and the mean size ranging from 67 to 95 nm. IHC analysis revealed substantial interindividual heterogeneity in the expression of Ki-67, CEA, and CK7 markers across patient tumors and corresponding PDXOs, providing valuable insights into the proliferation, differentiation, and aggressiveness. The treatment with yCD::UPRT-PlacMSC-cCM + 5-FC induced uniform cytotoxic effect across CAF samples and PDXOs. Besides, there were no apparent differences in cell viability after the 5-day treatment with yCD::UPRT-PlacMSC-cCM + 5-FC between monocultures and coculture models.

Conclusion:

Our study demonstrates the potential of engineered PlacMSC-derived EVs as a new therapeutic approach for PDAC, inducing cytotoxic effects across patient-derived models. Given the limited translation of preclinical findings into clinical practice, our findings emphasize the need for more advanced preclinical models that better recapitulate the PDAC tumor microenvironment.