# Creating a targeted micropharmacy for improved cellular cancer therapies

> **NIH NIH F32** · SLOAN-KETTERING INST CAN RESEARCH · 2020 · $41,891

## Abstract

Despite recent progress with engineered T cell therapies in the treatment of cancer, resistance to the activity of
these cells remains a significant hurdle to their success. Increased potency, greater penetration of solid
tumors, and mechanisms to defeat the immunosuppressive tumor microenvironment are still needed for many
cancer types. To address this problem, we propose an innovative strategy that overcomes tumor resistance by
modifying CAR T cells to constitutively express an enzyme that synthesizes a potent cytotoxic chemotherapy
drug from a non-toxic prodrug at the cancer cell surface or into the tumor microenvironment. The selective and
local elaboration of potent anti-neoplastic drugs at the tumor site may overcome the immune resistance to the
cells, and tumor escape by antigen loss variants, as the drug does not rely on tumor antigen expression and
may diffuse locally. These live and regulatable anticancer agents will serve as targetable micropharmacies that
synthesize the drug itself, not simply deliver a payload. We term them “Synthetic Enzyme-Activated KillER”
cells or SEAKER cells. SEAKER cells will combine the innate tumor killing ability of CAR T cells with the
specific activation of a cytotoxic drug at the tumor site. The aims of this project are to design and construct
various SEAKER cell systems and validate their functions in vitro, and to then test the efficacy and
pharmacological properties of the SEAKER systems in various animal tumor models. CAR T constructs
targeting the well-established CD19 tumor antigen or the ubiquitous Wilm's tumor protein will be engineered to
express the carboxypeptidase CPG2, which can activate a cytotoxic agent modified with an inhibitory
glutamate residue that renders it non-toxic. In the presence of CPG2, the inhibitory glutamate on the prodrug
will be cleaved and the drug will become active. Various enzyme/prodrug systems will be developed and tested
in vitro, and optimal conditions for prodrug activation and constitutive CPG2 expression will be determined. A
cell-surface anchored form and a secreted form of CPG2 will be engineered. The optimized SEAKER
constructs will be used to generate CAR-T cells from primary human T cells, and infused into various
xenogeneic murine tumor models. Pharmacokinetics and in-vivo expansion of the SEAKER cells will be
measured. The ability of the SEAKER cells to shrink tumor mass and extend survival of tumor-engrafted mice
will be assessed and compared to traditional CAR-T cells. Distribution of prodrug versus activated drug will be
examined using LCMS/MS technology. These studies will indicate the feasibility and efficacy of this novel and
promising approach to advancing cellular therapies in cancer treatment.

## Key facts

- **NIH application ID:** 9839497
- **Project number:** 5F32CA224438-03
- **Recipient organization:** SLOAN-KETTERING INST CAN RESEARCH
- **Principal Investigator:** Thomas J Gardner
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $41,891
- **Award type:** 5
- **Project period:** 2018-02-01 → 2020-08-21

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9839497

## Citation

> US National Institutes of Health, RePORTER application 9839497, Creating a targeted micropharmacy for improved cellular cancer therapies (5F32CA224438-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9839497. Licensed CC0.

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