# Metabolic Recycling and Compartmentalization in Tumor Progression

> **NIH NIH K00** · WHITEHEAD INSTITUTE FOR BIOMEDICAL RES · 2022 · $105,154

## Abstract

PROJECT SUMMARY
 Cancer cells elevate nutrient catabolism, causing excess production and accumulation of metabolic
waste, especially lactate and ammonia. Using stable isotope tracing and mass spectrometry, we discovered
that breast cancer cells scavenged ammonia generated by amino acid catabolism as a re-purposed nitrogen
source for biomass (Spinelli et al. Science, 2017). Ammonia recycling accelerated proliferation in 3D cell
culture and in vivo mouse xenograft models. These studies lead to two follow-up questions that will be
addressed in Specific Aim 1 (F99 phase) of this proposal. First (Aim 1A), what is the mechanism by which
ammonia stimulates breast cancer proliferation? Preliminary data supports the hypothesis that subcellular
compartmentalization of ammonia metabolism is required for its effect on proliferation rate. Using metabolic
tracing and rapid immunoprecipiation, we tracked the localization of ammonia assimilation to the mitochondria
and the subsequent efflux of metabolites to the cytosolic fraction, showing a role in ammonia-stimulated
proliferation. Second (Aim 1B), what is the effect of this novel ammonia-recycling pathway on response to
therapy? Preliminary data shows that ammonia assimilation circumvents the effect of glutaminase (GLS)
inhibitors through replenishing glutamate levels via glutamate dehydrogenase (GDH). Our proposed studies
will determine if GDH and GLS inhibition are synergistic in vivo and in primary breast cancer tumors to
elucidate a mechanism by which breast cancer cells are resistant to GLS inhibition.
 Beyond ammonia, mitochondria promote tumor growth and proliferation through numerous metabolic
pathways. However, the mechanisms by which nutrients traverse the inner mitochondrial membrane are little
studied, particularly because 45% of the mitochondria nutrient transporter family is uncharacterized. Therefore,
using my expertise in metabolite tracing and mass spectrometry in addition to new skills gained in genetic
(CRISPR) screening and bioinformatics, the proposed studies (Aim 2, K00 phase) will systematically assess
the role of mitochondrial nutrient transporters in tumor growth and survival. These data will be the first to
globally evaluate the essentiality of metabolic compartmentalization in cancer cells harboring oncogenic drivers
such as KRAS, IDH and PI3K mutations. Furthermore, this study will elucidate the function of uncharacterized
mitochondrial nutrient transporters.
 In addition to the proposed studies, the fellowship training plan includes gaining experience with
mentorship, taking courses on responsible conduct of research, team management, and budgeting, and
attending scientific conferences such as the Tumor Metabolism Keystone meeting to develop a network of
scientific collaborators. The proposed studies will occur at Harvard Medical School and The Broad Institute,
which have environments with the equipment, technology, core facilities, potential for collaboration, and the
resources fo...

## Key facts

- **NIH application ID:** 10356031
- **Project number:** 5K00CA234839-05
- **Recipient organization:** WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
- **Principal Investigator:** Jessica Brooke Spinelli
- **Activity code:** K00 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $105,154
- **Award type:** 5
- **Project period:** 2019-03-01 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10356031

## Citation

> US National Institutes of Health, RePORTER application 10356031, Metabolic Recycling and Compartmentalization in Tumor Progression (5K00CA234839-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10356031. Licensed CC0.

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