Mitochondrial mechanisms of chemoprevention by polyphenols in an in vitro model of benzo[a]pyrene carcinogenesis Kosar Omidian

Cancer prevalence In Canada 1 in 4 Canadians will die from cancer 2 in 5 Canadians will develop cancer in their lifetime 196,900 Canadians will be diagnosed with cancer in 2015 78,000 Canadians will die from cancer in 2015 Canadian cancer statistics, 2015

Why cancer prevention is so important?

According to the WHO reports: Prevention offers the most cost-effective long-term strategy for the control of cancer At least one-third of all cancer cases are preventable

Diet and cancer prevention Nutritional factors contribute to 20-60% of cancers worldwide One-third of cancers are associated with diet High consumption of fruits and vegetables is linked to reduction in overall cancer risk Vineis & Wild, 2014, Lancet

Polyphenols We chose different classes of polyphenols from different food sources Quercetin Berberine Catechin Resveratrol Anthocyanins Polyphenols are the most common antioxidants in diet

What is Benzo[a]pyrene?

One of the most potent polycyclic aromatic hydrocarbons (PAHs) Classified as a group 1 carcinogen in International Agency for Research on Cancer (IARC) Ubiquitous Charbroiled and barbequed meats are the main food sources It is known to damage mitochondria (Zhang et al., 2014)

Research questions

Does B[a]P induce ROS and inflammation? Do polyphenols prevent B[a]P-induced ROS and inflammation? Does B[a]P induce mitochondrial dysfunction? Do polyphenols induce mitochondrial biogenesis and inhibit Warburg effect? Does B[a]P induce neoplastic transformation? Do polyphenols prevent B[a]P-induced neoplastic transformation and protect against carcinogenesis?

What are the mitochondria? ATP production (more than 90% in normal cells) Metabolism of biomolecules Main site of ROS generation Apoptosis Modica-Napolitano & Singh, 2004

ROS damage cells in carcinogenesis Oxidative stress ROS damage cells in carcinogenesis Indirect: Signaling pathway Direct: Biomolecular damage Tumorigenesis Cell survival Inflammation Cell proliferation Angiogenesis Resistance to apoptosis Metastasis DNA mutations Liou & Storz, 2010

Mitochondrial biogenesis and its role in cancer prevention Is a process of formation of healthy and functional mitochondria Induction of mitochondrial biogenesis is associated with ROS inhibition We hypothesize that through induction of mitochondrial biogenesis by polyphenols we can prevent cancer development

Study design

In vitro model of carcinogenesis Bhas 42 fibroblast cells (v-Ha-ras-transfected BALB/c 3T3 cells) They have been used in B[a]P carcinogenesis They develop neoplastic transformation after exposure with a carcinogen

Neoplastic transformation

Pre-treated with polyphenols 5μM (for 2 h) Treatment with B(a)P 4 μM Fluorescent dyes Transformation assay qPCR

Do Polyphenols inhibit B(a)P-induced ROS generation and TNF-α expression?

Benzo (a) pyrene 4 µM Quercetin 5 µM+ B(a)P Berberine 5 µM+ B(a)P Cells (untreated) Catechin 5 µM+ B(a)P Resveratrol 5 µM+ B(a)P Cyanidin 5 µM+ B(a)P

* Significantly different from B(a)P

* Significantly different from B(a)P

Do Polyphenol induce mitochondrial biogenesis?

* Significantly different from B(a)P

Mitochondrial content Cells (untreated) Benzo(a)pyrene 4 µM Quercetin 5µM+ B(a)P Berberine 5µM+ B(a)P Catechin 5 µM+ B(a)P Resveratrol 5 µM+ B(a)P Cyanidin 5 µM+ B(a)P

* Significantly different from B(a)P

Do Polyphenols inhibit B(a)P-induced neoplastic transformation?

* Significantly different from B(a)P

Take-home message BaP induces ROS generation and inflammation, while polyphenols reverse this effect BaP induces mitochondrial dysfunction while polyphenols induce mitochondrial biogenesis and mitochondrial function BaP causes neoplastic transformation (foci formation) in Bhas 42 cells, while polyphenols reverse this effect

Acknowledgments My supervisor: Dr. Brian Bandy My lab mates College of Pharmacy and Nutrition Saskatchewan Health Research Foundation

Thank you!