Article Text

Download PDFPDF

1119 Selective reversal of key features of T cell exhaustion in an in vitro model by a SMARCA4/2 ATPase inhibitor
  1. Eden Kleiman1,
  2. Linda Liang1,
  3. Jared Gunn1,
  4. Mingfa Zang1,
  5. Marrit Putker1,
  6. Ludovic Bourre1 and
  7. Pirouz Daftarian1,2
  1. 1Crown Bioscience Inc., San Diego, CA, USA
  2. 2JSR Life Sciences, Sunnyvale, CA, USA
  • Journal for ImmunoTherapy of Cancer (JITC) preprint. The copyright holder for this preprint are the authors/funders, who have granted JITC permission to display the preprint. All rights reserved. No reuse allowed without permission.


Background Repeated T cell stimulation that occurs in both chronic viral infections and the tumor microenvironment progressively degrades functionality in a process referred to as T cell exhaustion or T cell dysfunction. Developing in vitro assays to model drug responses to compounds that potentially reverse/inhibit this process is urgently needed to propel next generation cancer therapeutics. Exhausted T cells in cancer display dramatically upregulated surface expression of key co-inhibitory receptors such as PD-1, have reduced effector cytokine secretion and have an altered epigenetic landscape. Nuclear architecture and chromatin accessibility impacts activation and exhaustion of T cells. Particularly, mSWI/SNF ATPase-specific inhibitors and degraders have recently been shown to attenuate T cell exhaustion and increase memory T cell phenotypes, where inhibition of SMARCA4/2 ATPase activity resulted in significant lowering of PD-1+/TIM-3+ double positive exhausted T cell populations, increasing progenitor exhausted cells (PD-1+/TIM-3-), lowering terminally exhausted CD39+ population and enhancing associated with lowered apoptosis in treated cells. Here, we employed our previously reported in vitro T cell exhaustion model, to test a novel inhibitor of SMARCA4/2 ATPase activity, FHT-1015.

Methods To model chronic T cell stimulation in vitro, we repeatedly stimulated human PBMCs from 4 donors with CD3/CD28 Dynabeads. FHT-1015 was included or not included with each Dynabead treatment. Following stimulation, supernatant was harvested for IL-2, TNF-alpha and IFN-gamma cytokine analysis and T cells were collected for flow cytometry i (PD-1, TIM-3, LAG-3, CD38, CD39, CD4, CD8, CD3, Live/Dead).

Results Treatment of exhausted T cells, in our model, with FHT-1015, resulted in selective and consistent of key co-inhibitory receptor surface expression; TI. However, PD-1 surface expression was unchanged while that of CD38 was elevated. Cytokine secretion of IL-2, TNF-alpha and IFN-gamma were all reduced with FHT-1015 treatment. This selective impact of FHT-1015 in modulating T cell exhaustion pathways validates the use of this assay to screen small molecules drugs in reversing T cell exhaustion.

Conclusions In conclusion, our in vitro T cell exhaustion assay allows identification of immunomodulatory drug candidates that have the potential to regulate the T cell exhaustion developmental continuum and T cell functionality after terminal differentiation.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.