# Presentation: 041047

##  The Aryl Hydrocarbon Receptor asa Molecular Target ofChemopreventive Phytochemicals

**Pawel Sienkiewicz, Ph.D. ****•**** Sara Bass, M.S. ****•**** Henry Ciolino, Ph.D.  ****•**** Chris MacDonald, Ph.D.**

- Cancer is preventable.
- Diets rich in fruits and vegetables are associated with a reduced risk of many types of cancers.

## Many phytochemicals are believed to affect every stage of the cancer process

- Chemopreventive		Cancer Prevented 	Mechanisms            Phytochemicals	Source	  (animal models)	   of Action
- Alkyl sulfides and disulfides	Allium	Esophagus, Colon,	Phase II, GSTSulfide volatiles 		LungAllyl cystenes
- Monoterpenes	Citrus	Mammary, Pancreas,	Phase II, GST,Lemonene		Skin, Lung, Liver	UDP-GT,			Phase I
- Isothiocyanates	Crucifers	Liver, Lung,	Phase II, GST 		Mammary
- Polyphenols	Teas	Colon, Lung,	Phase II (GST,Epigallocatechin gallate		Skin, Liver	QR), Phase I,			AP-1
- Curcumin	Turmeric	Colon, Skin	Phase II, GST,			Cox II

**Notes:**
f32712

## Carcinogenesis

**Activation of Procarcinogens by CYPs**

**Gene Mutation Proto-oncogene Tumor Suppressor**

**Angiogenesis****Program Cell Death**

**DNA Damage**

**Normal****Cells**

**Promotion**

**Mutant****Cells**

**Progression**

**Benign****Tumors**

**Malignant****Tumors**

**Phytochemicals****Other Chemopreventive Agents**

**X**

**Initiation**

**X**

**X**

## TCDD

- Benzo[a]pyrene

- DMBA

**Notes:**
From 21668

## The Aryl Hydrocarbon Receptor Pathway

**The Aryl Hydrocarbon Receptor Pathway**

## Aryl Hydrocarbon Receptor “Battery” of Genes

-  Phase 1 enzymes: 	• Cytochrome P450 1A1 	• Cytochrome P450 1A2 	• Cytochrome P450 1B1
-  Phase 2 enzymes: 	• Aldehyde dehydrogenase 	• Glutathione-S-transferase  	• UDP-glucuronosyltransferase 	• NADPH-quinone-oxidoreductase

**Notes:**
From 21668

## MacDonald, Cancer Res. 61: 2001

- MacDonald, *Cancer Res*. 61: 2001
- Ciolino, *J. Biol. Chem*. 274:1999
- Ciolino, *Cancer Res.* 62: 2002

- Ciolino, *Cancer Res*. 58:1998
- Ciolino, *Biochem. J.* 340:1999
- Ciolino, *Br. J. Cancer* 79:1999

**Notes:**
F32712 and pathway slides

## Cellular Defense and Carcinogenesis Section

- Curcumin, DBM

- Resveratrol

- Diosmetin, Diosmin

- Galangin

- Kaempferol, Quercetin

## Salicylates

- Salicylates are an important class of phytochemicals present in human diets.
- Aspirin, a synthetic salicylate, is the most studied chemopreventive agent.

- MacDonald, *Cancer Res.* 64: 2004
- Ciolino, *Carcinogenesis* 27, 2006

## Salicylamide Inhibits Aryl Hydrocarbon-induced CYP Enzyme Activity in HepG2 Cells

**Notes:**
31216 SV Figure 1(6)

## Aryl Hydrocarbon Receptor Pathway

**Drugs**

**Ligand Binding**

**Gel Shift**

**Transcription**

**mRNA Level**

**Protein and Enzyme Activity**

**Aryl Hydrocarbon Receptor Pathway**

**Notes:**
F32712 and pathway slides

## Salicylamide is a synthetic salicylate used in combination with aspirin and other analgesic mixtures. Thus it has already been used extensively in humans.
There is no published literature on salicylamide other than as an analgesic.
Its chemopreventive properties are unknown.

- There is no published literature on salicylamide other than as an analgesic.
- Its chemopreventive properties are unknown.

**Salicylamide**

## Effect of Salicylamide on TCDD-induced CYP1A1 Activity in HepG2 Cells

## Effect of Salicylamide on TCDD-induced Binding of the AhR to the XRE of CYP1A1 in HepG2 Cells

## Salicylamide Competes with TCDDfor Binding to the AhR in HepG2 Cells

## Novel Drugs That Inhibits the Expressionof Carcinogen-activating Enzymes in Human Hepatoma HepG2 Cells

- Aspirin-H2S (ACS30)
- Diclofenac-H2S (ACS15) is a NSAID for the treatment of inflammation and pain relief.
- Valproate-H2S (ACS2) is a drug for Epilepsy treatment in humans. The LD50 orally in rats is 670 mg/kg (*Food Cosmet. Toxicol*. 2: 327, 1964).

## Measurement of Cell Viability by MTT Assay

**Notes:**
38835 Fig-6 mtt assay.tif

## Aryl Hydrocarbon Receptor Pathway

**Drugs**

**Ligand Binding**

**ChIP**

**Transcription**

**mRNA Level**

**Protein and Enzyme Activity**

**Aryl Hydrocarbon Receptor Pathway**

**Notes:**
F32712 and pathway slides

## ACS15 Inhibits Aryl Hydrocarbon-induced CYP Enzyme Activity in HepG2 Cells

**Notes:**
38835 Fig-5 erod tcdd dmba.tif

## ACS15 Inhibits Aryl Hydrocarbon-induced  Enzyme Activities in Recombinant CYPs

**Notes:**
38835 Fig-1 cyp low conc.tif

## Novel Drugs That Inhibits the Expressionof Carcinogen-activating Enzymes in Human Hepatoma HepG2 Cells

- Valproate-H2S (ACS2) is a drug for Epilepsy treatment in humans. The LD50 orally in rats is 670 mg/kg (*Food Cosmet. Toxicol*. 2: 327, 1964).

## Val-H2S Inhibits Aryl Hydrocarbon-induced CYP Enzyme Activity in HepG2 Cells

**Notes:**
38835 Figure 1

## Yeh, J. Biol. Chem. 276: 2001.

- Yeh, *J. Biol. Chem.* 276: 2001.

## Integrated Study of Chemoprevention against Aryl Hydrocarbons

**To examine the effect of ****chemopreventive agents and S-NSAIDs****on novel biochemical pathways involved in****the detoxification of aryl hydrocarbons.**
**David Wink, NCI****David Roberts, NCI****Terry Moody, NCI**

**To establish whether the AhR ****and the pathway it mediates is a ****molecular target of chemopreventive ****compounds and S-NSAIDs.**
**David Wink, NCI****Piero Del Soldato, CTG Pharma****Ed Sausville, Univ. of MD**

**To test the hypothesis that****chemopreventive agents and ****S-NSAIDs inhibit carcinogen-induced****lung and breast tumorigenesis in rodents ****by affecting the AhR battery of genes.**
**Lucy Anderson, NCI****Mariam Poirier, NCI****Piero Del Soldato, Pharma**