Erschienen in:
26.10.2021 | Original Article
4-(N)-Docosahexaenoyl 2’, 2’-difluorodeoxycytidine induces immunogenic cell death in colon and pancreatic carcinoma models as a single agent
verfasst von:
Stephanie Hufnagel, Haiyue Xu, Michael F. Colemam, Solange A. Valdes, Kristyn A. Liu, Stephen D. Hursting, Zhengrong Cui
Erschienen in:
Cancer Chemotherapy and Pharmacology
|
Ausgabe 1/2022
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Abstract
Purpose
Docosahexaenoyl difluorodeoxycytidine (DHA–dFdC) is an amide with potent, broad-spectrum antitumor activity. In the present study, DHA–dFdC’s ability to induce immunogenic cell death (ICD) was tested using CT26 mouse colorectal cancer cells, an established cell line commonly used for identifying ICD inducers, as well as Panc-02 mouse pancreatic cancer cells.
Methods
The three primary surrogate markers of ICD (i.e., calreticulin (CRT) surface translocation, ATP release, and high mobility group box 1 protein (HMGB1) release) were measured in vitro. To confirm DHA–dFdC’s ability to induce ICD in vivo, the gold standard mouse vaccination studies were conducted using both CT26 and Panc-02 models. Additionally, the effect of DHA–dFdC on tumor response to anti-programmed cell death protein 1 monoclonal antibody (anti-PD-1 mAb) were tested in mice with pre-established Panc-02 tumors. RNA sequencing experiments were conducted on PANC-1 human pancreatic cancer cells treated with DHA–dFdC, dFdC, or vehicle control in vitro.
Results
DHA–dFdC elicited CRT surface translocation and ATP and HMGB1 release in both cell lines. Immunization of mice with CT26 or Panc-02 cells pretreated with DHA–dFdC prevented or delayed the development of corresponding secondary live challenge tumor. DHA–dFdC enabled Panc-02 tumors to respond to anti-PD-1 mAb. RNA sequencing experiments revealed that DHA–dFdC and dFdC differentially impacted genes related to the KRAS, TP53, and inflammatory pathways, and DHA–dFdC enriched for the unfolded protein response (UPR) compared to control, providing insight into DHA–dFdC's potential mechanism of inducing ICD.
Conclusion
DHA–dFdC is a bona fide ICD inducer and can render pancreatic tumors responsive to anti-PD-1 mAb therapy.