# Ultra-Small Epigenetic-Regulating Nanocarrier for Enhanced Synthetic Lethal Therapy

> **NIH NIH R01** · UNIVERSITY OF NEBRASKA MEDICAL CENTER · 2024 · $362,741

## Abstract

Project Summary:
PARP inhibitors-based synthetic lethal therapy, such as BMN673 (Talazoparib), shows great efficacy for BRCA
mutated (or homologous recombination repair (HRR)-deficient) cancers in preclinical and clinical studies, but
demonstrates limited efficacy for majority of cancer types that are HRR proficient. To improve the PARPi efficacy
and extend their therapeutic application, additional combination approaches are necessary. 5-azacytidine (AZA)
is a DNA methylation inhibitor, which shows increasing clinical use for epigenetic therapy of solid tumors. AZA
has been reported to enhance PARPi response through trapping large DNMT-PARP1 complexes to DNA break
sites and enhancing formation of cytotoxic double-strand breaks (DSBs). Based on our preliminary data and data
from others, AZA may also affect DNA repair, inducing HRR defects and sensitizing tumors to PARPi. Moreover,
we hypothesize that combination of AZA with BMN673 may enhance the tumor immune response through
generation of novel neoantigens and upregulation of MHC class I molecules. However, the effectiveness of this
combination therapy is limited by the poor bioavailability of the two drugs and the challenge of codelivery to
tumors due to the distinct physiochemical properties of BMN and Aza. In our preliminary studies, we developed
a small sized nanocarrier that could selectively accumulate in the tumors and effectively penetrate to the core of
experimental tumors, importantly, it could efficiently load both hydrophilic AZA and hydrophobic agent BMN673
and was more effective in suppressing tumor growth in PARPi-insensitive NSCLC tumor models at relatively
lower doses. We propose to further optimize the BMN/PAZA formulation (Aim 1) and evaluate their in vivo
pharmacokinetics, biodistribution and tumor penetration efficiency using tumor models that closely mimic human
NSCLC (Aim 2). We will also investigate the therapeutic efficacy and the underlying mechanism (Aim 3). These
studies will address the issues of off-target toxicity of AZA and PARPi, and provide a promising and safe strategy
to expand the clinical use of synthetic lethal therapy to both HRR-deficient and HRR-proficient cancer patients.

## Key facts

- **NIH application ID:** 10979025
- **Project number:** 1R01CA287091-01A1
- **Recipient organization:** UNIVERSITY OF NEBRASKA MEDICAL CENTER
- **Principal Investigator:** Jingjing Sun
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $362,741
- **Award type:** 1
- **Project period:** 2024-07-09 → 2029-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10979025

## Citation

> US National Institutes of Health, RePORTER application 10979025, Ultra-Small Epigenetic-Regulating Nanocarrier for Enhanced Synthetic Lethal Therapy (1R01CA287091-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10979025. Licensed CC0.

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