# Improving CAR T cell therapy for brain tumors using immune competent models

> **NIH NIH K99** · ST. JUDE CHILDREN'S RESEARCH HOSPITAL · 2022 · $125,023

## Abstract

PROJECT SUMMARY/ABSTRACT
The overall objective of this study is to engineer a potent CAR T cell therapy for high grade glioma (HGG),
a subgroup of brain tumors for which outcomes remain poor. CAR T cell therapy is an innovative technology
based on adoptive transfer of antigen-specific T cells engineered to elicit a clinically effective and specific
immune response against tumor cells. Early clinical studies in HGG patients demonstrated safety of CAR T cell
therapy for brain tumors; yet, only limited benefits were observed. Lack of efficacy is most likely multifactorial
and include heterogenous antigen expression, limited homing to and penetration of tumors, T cell exhaustion
and limited persistence, as well as the immunosuppressive tumor microenvironment (TME). Therefore, the
central hypothesis of this proposal is that optimized design and additional genetic modifications of CAR
T cells will improve their antitumor effects, and that these interventions will be evaluated in immune
competent mouse models that closely mimic human disease. Three interrelated research aims are proposed
to test this hypothesis and the rationale of each is outlined below. First, CAR design has to be optimized and
evaluated in immune competent glioma models. In Aim 1, I will generate CAR T cells containing different co-
stimulatory domains (CD28.ζ, 41BB.ζ, CD28.mutζ, and 41BB.mutζ), and compare their activity in vitro and in
vivo. Second, a genome wide screen in primary T cells has identified key regulators of T cell activation post T-
cell receptor (TCR) stimulation. Identified genes belong to molecules that regulate cell cycle, proliferation, and
downstream TCR signaling including SOCS1, RASA2, or CBLB. In Aim 2, I will therefore explore if CRISPR-
Cas9 mediated silencing of Socs1, Rasa2, and/or Cblb enhances the effector functions of CAR T cells. The
independent Aim 3 will then explore a dual CAR targeting approach in which I will not only target glioma cells
but also immunosuppressive cells within the glioma microenvironment. These studies are focused on tumor
associated macrophages (TAMs), since they are abundantly present in gliomas and play a critical role in shaping
the TME. To support the feasibility of this project, I have adapted the well-established immune competent GL261
glioma model to study CAR T cell therapies targeting the relevant tumor antigen B7-H3, which is not only
expressed by GL261 cells but also in a broad range of pediatric and adult brain tumors. In addition, my
preliminary studies indicate that `prototype' B7- H3 CAR T-cells readily recognize and kill GL261 cells in vitro
and have antitumor activity in vivo, highlighting that the developed model is well suited for the proposed aims of
this project. State of the art technique will be used in all three Aims to not only study the function and in vivo fate
of CAR T-cells, but also their antitumor activity, and how CAR T-cells interact with glioma- infiltrating immune
cells. Completion of this stud...

## Key facts

- **NIH application ID:** 10322192
- **Project number:** 5K99CA256262-02
- **Recipient organization:** ST. JUDE CHILDREN'S RESEARCH HOSPITAL
- **Principal Investigator:** Dalia Haydar
- **Activity code:** K99 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $125,023
- **Award type:** 5
- **Project period:** 2021-01-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10322192

## Citation

> US National Institutes of Health, RePORTER application 10322192, Improving CAR T cell therapy for brain tumors using immune competent models (5K99CA256262-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10322192. Licensed CC0.

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