journal contribution
posted on 2023-03-31, 02:47 authored by Simona Dalin, Mark R. Sullivan, Allison N. Lau, Beatrice Grauman-Boss, Helen S. Mueller, Emanuel Kreidl, Silvia Fenoglio, Alba Luengo, Jacqueline A. Lees, Matthew G. Vander Heiden, Douglas A. Lauffenburger, Michael T. Hemann Fig. S1. Conditioned media does not affect growth of PDAC cells except at 100% supplementation but does protect human PDAC cell lines regardless of P53 status. (A-E) Arbitrary units of resazurin fluorescence representing growth of PDAC cells after 3 days in culture are shown for cells cultured with the indicated supplement of media conditioned for the indicated number of days. Data show three biological replicates +/- SEM. ***, P {less than or equal to} 0.001, ns, not significant (one-way ANOVA with Bonferroni post-tests). (G) Viability of PDAC organoids after the indicated treatment with 0.05 uM gemcitabine, 20% CM, and/or 20 uM dC. Data show three biological replicates +/- SEM. Mean and SEM are indicated on the plot. One-way ANOVA with Bonferroni post-tests reveals no significant difference between gemcitabine treatment and gemcitabine + CM treatment, or gemcitabine + dC treatment. (F) Viability of the indicated cell lines at the indicated doses of gemcitabine with or without CM supplementation. Data show three biological replicates +/- SEM. *, P {less than or equal to} 0.05, **, P {less than or equal to} 0.01, ns, not significant (two-tailed one sample t-test).
Funding
NIH
NCI
Damon Runyon Cancer Research Foundation
MIT Center for Precision Cancer Medicine and the Ludwig Center at MIT
History
ARTICLE ABSTRACT
Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer deaths in the United States. The deoxynucleoside analogue gemcitabine is among the most effective therapies to treat PDAC, however, nearly all patients treated with gemcitabine either fail to respond or rapidly develop resistance. One hallmark of PDAC is a striking accumulation of stromal tissue surrounding the tumor, and this accumulation of stroma can contribute to therapy resistance. To better understand how stroma limits response to therapy, we investigated cell-extrinsic mechanisms of resistance to gemcitabine. Conditioned media from pancreatic stellate cells (PSC), as well as from other fibroblasts, protected PDAC cells from gemcitabine toxicity. The protective effect of PSC-conditioned media was mediated by secretion of deoxycytidine, but not other deoxynucleosides, through equilibrative nucleoside transporters. Deoxycytidine inhibited the processing of gemcitabine in PDAC cells, thus reducing the effect of gemcitabine and other nucleoside analogues on cancer cells. These results suggest that reducing deoxycytidine production in PSCs may increase the efficacy of nucleoside analog therapies.
This study provides important new insight into mechanisms that contribute to gemcitabine resistance in PDAC and suggests new avenues for improving gemcitabine efficacy.
