# Integrative approaches to elucidate p53 transcriptional networks during carcinogenesis

> **NIH NIH R35** · STANFORD UNIVERSITY · 2023 · $125,479

## Abstract

PROJECT SUMMARY/ABSTRACT
The TP53 tumor suppressor gene is mutated in over half of all human cancers, but the mechanisms through
which p53 suppresses cancer in vivo remain incompletely understood. Notably, there are no standard-of-care
cancer therapies based on the p53 pathway. In this proposal, we strive to deconstruct the pathways through
which p53 suppresses cancer to illuminate pathways dysregulated upon p53 loss that could ultimately be
targeted therapeutically. We previously performed unbiased in vivo shRNA and CRISPR/Cas9 screens for p53
target genes important for tumor suppression and identified Zmat3 as the top hit in both screens. Zmat3
encodes a zinc finger RNA-binding protein that we found acts by modulating alternative splicing, revealing a
new branch of p53-mediated tumor suppression. Given the critical role for alternative splicing in cancer, we
hypothesize that studying p53 pathways at the post-transcriptional level, such as through splicing and
proteomics analyses, will yield novel insights into p53-mediated tumor suppression. In Theme 1, we propose to
identify p53-dependent splicing and proteome changes, including both Zmat3-dependent and Zmat3-
independent ones, that could explain tumor suppression in mouse LUAD and HCC. We will test the importance
of genes found in these analyses for LUAD and HCC suppression using a quantitative in vivo tumor assay
known as Tuba-seq. In Theme 2, we will pursue our observation that p53 repurposes a role in lung
regeneration, in which it drives alveolar type 1 cell differentiation upon lung injury, to suppress LUAD. Through
single cell (sc)RNA-seq and scATAC-seq analyses, we will ask how p53 status dictates the evolutionary path
of KrasG12D-expressing alveolar type 2 cells and how p53 transcriptional programs change with cell state
across LUAD evolution in mouse models. We will also ask how cells in the tumor microenvironment (TME)
affect cancer cell trajectories in wild-type and p53-deficient tumors. To define genes functionally important for
cancer cell state transitions and crosstalk between cancer cells and TME components, we will employ
scPerturb-seq. In this diversity supplement, Dr. Tambo will perform a new project related to Theme 2 of the
R35 to expand our understanding of p53 action in LUAD suppression by using proteomics to identify p53
interacting partners. We will perform tandem affinity tag purification of wild-type p53 and p53 transactivation
domain mutants with altered tumor suppression properties to identify those p53-interactors most relevant for
tumor suppression. We will then test the roles of these p53-interacting proteins in tumor suppression in a
mouse transplant system and we will define the roles of these p53-interactors in p53 target gene regulation
and proliferation suppression. Ultimately, we will identify those p53-interacting proteins most relevant for LUAD
suppression in the scPerturb-seq experiments in vivo. Collectively, these studies will deconstruct p53-mediate...

## Key facts

- **NIH application ID:** 10806805
- **Project number:** 3R35CA197591-09S1
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** LAURA D ATTARDI
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $125,479
- **Award type:** 3
- **Project period:** 2015-08-14 → 2029-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10806805

## Citation

> US National Institutes of Health, RePORTER application 10806805, Integrative approaches to elucidate p53 transcriptional networks during carcinogenesis (3R35CA197591-09S1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10806805. Licensed CC0.

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