# Skin Cancer Chemoprevention by Silibinin: Mechanisms and Efficacy

> **NIH NIH R01** · UNIVERSITY OF COLORADO DENVER · 2021 · $155,500

## Abstract

Project Summary Abstract
The most important risk factor for basal cell carcinoma (BCC), accounting for ~4 million new cases
each year, is solar ultraviolet B radiation (UVB) exposure. One of the key molecular features of BCC
is sustained activation of hedgehog (Hh) pathway through inactivating mutations in tumor suppressor
gene Ptch or activating mutations in Smoothened (SMO). Consequently, extensive efforts have been
made to target activated Hh pathway to treat BCC, though with toxic side effects and drug resistance.
Due to these limitations, recent studies have also focused on chemopreventive strategies to manage
BCC. In specific Aim I of the parent grant, we proposed to determine the preventive efficacy of topical
application of silibinin on a) chronic UVB-induced macroscopic BCC formation as well as b) on the
progression of UVB-induced microscopic BCC lesions to more advanced forms of BCCs. Notably, the
outcomes from these studies (in the parent grant) have shown that topical silibinin application has
significant protective effects against BCC growth and progression (pl. refer to efficacy outcomes
section, B5: Fig 1-4). Given these important findings in our completed studies in the parent grant and
the fact that silibinin has also shown strong chemopreventive and anti-cancer potential when given
orally (by gavage and/or dietary feeding) in other cancers [including skin squamous cell carcinoma
(SCC)], there is a compelling likelihood that silibinin would also prevent BCC progression when given
orally. Such studies were not proposed in the parent grant, but (based on our completed
studies) merit detailed investigation and forms the basis of this supplement; we expect similar
protective effects using oral silibinin dosing in our proposed studies. Also, the anticipated efficacy of
orally administered silibinin against BCC progression from ‘micro’ to ‘macro’ grade will highlight the
tremendous potential of silibinin for its preventive and interventive applications against BCC
progression. Our aims are: I) to determine the preventive efficacy of oral feeding of silibinin on the
progression of UVB-induced microscopic BCC lesions to more advanced forms of BCCs; and II) to
determine potential biomarkers of BCC chemopreventive efficacy of silibinin; specifically, to identify
silibinin-associated gene expression biomarkers and correlate them with the observed effects.
Considering that silibinin has a long history of human use as a widely consumed dietary
supplement around the world and is considered exceptionally safe, this supplement proposal
is highly significant as successful results from proposed aims would have strong translational
implications in the prevention and intervention of BCC.

## Key facts

- **NIH application ID:** 10287350
- **Project number:** 3R01CA140368-10S1
- **Recipient organization:** UNIVERSITY OF COLORADO DENVER
- **Principal Investigator:** Rajesh Agarwal
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $155,500
- **Award type:** 3
- **Project period:** 2010-03-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10287350

## Citation

> US National Institutes of Health, RePORTER application 10287350, Skin Cancer Chemoprevention by Silibinin: Mechanisms and Efficacy (3R01CA140368-10S1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10287350. Licensed CC0.

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