# LUNG TUMOR PROMOTION BY BHT

> **NIH NIH R01** · UNIVERSITY OF COLORADO · 1991 · $146,112

## Abstract

Promotion of mouse lung tumors by the antioxidant butylated hydroxytolune
(BHT; 2,6,-di-tert-butyl-4-methyl phenol) has become a powerful system for
understanding how a non-carcinogen enhances tumor growth in a internal
organ. This model can test whether putative mechanisms of skin tumor
promotion apply to a lung neoplasm which is analogous to a human cancer of
dramatically increasing incidence. The BHT/lung tumors system is one of the
few where metabolism of the promoter is requisite for function. We propose
that stimulation of initiated lung cell proliferation is mediated by
generation of electrophilic and/or free radical metabolites of BHT which
directly or indirectly lead to altered signal transduction and/or selective
cytotoxicity. The following three specific aims test this hypothesis.

(1) We will further investigate the current assumption that the principal
pathway for metabolic activation of BHT to a promoter involves
hydroxylation of a tert-butyl group. We will study the formation of this
metabolite, BHT-BuOH in vivo and in isolated Clara cells from the lungs of
sensitive (U+B+) and resistant (U+B-) strains of mice, and in established
lines of normal and neoplastic lung cells. Mechanisms of resistance to BHB
by U+B- mice will be studied by testing the promoting activity of BHT-BuOH
in these strains. (2) We will study the bioactivity of products generated
from BHT-BuOH in lung microsomes and Clara cells isolated from U+B+ and
U+B- strains, and by peroxidases. We will synthesize analogs of BHT-BuOH to
elucidate the role of the side-chain hydroxyl group in stimulating the
activity of its electrophilic metabolites, and evaluate deuterium isotope
effects on the activity of BHT-BuOH. (3) The biochemical actions of BHT
metabolites putatively related to tumor promotion we will investigate. This
includes a detailed evaluation of the effects of reactive BHT metabolites
on the Ca++messenger pathway, focusing on protein kinase C (PKC,
Ca++dependent protease (calpain), and an 80K substrate for PKC (p80). We
will examine perturbations in the concentration of isozymes of thee
proteins and the degree of expression of their genes, using immunoblotting
and Northern bloating techniques, following perturbation with BHT and its
reactive metabolites of bronchiolar Clara cells isolated from BHT-
responsive or insensitive strains of mice and in normal and neoplastic
lines of cultured alveolar type 2 cells. The hypothesis that elective
cytotoxicity mediate BHT-induced clonal expansion of urethane-initiated
lung cells will be examined by measuring the effects of BHT and metabolites
on cellular defense mechanisms and radical generation in isolated Clara
cells. The possibility of volent binding to critical proteins such as PKC,
calpain, or p80 by reactive metabolites of BHT will be examined.

## Key facts

- **NIH application ID:** 3171335
- **Project number:** 2R01CA033497-08
- **Recipient organization:** UNIVERSITY OF COLORADO
- **SAM.gov UEI:** SPVKK1RC2MZ3
- **Principal Investigator:** ALVIN M MALKINSON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1991
- **Award amount:** $146,112
- **Award type:** 2
- **Project period:** 1982-09-01 → 1994-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3171335

## Citation

> US National Institutes of Health, RePORTER application 3171335, LUNG TUMOR PROMOTION BY BHT (2R01CA033497-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3171335. Licensed CC0.

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