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

2. 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

3. Why cancer prevention is so important?

4. 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

5. 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

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

7. What is Benzo[a]pyrene?

8. 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)

9. Research questions

10. 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?

11. 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

12. 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

13. 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

14. Study design

15. 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

16. Neoplastic transformation

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

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

19. 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

20. * Significantly different from B(a)P

21. * Significantly different from B(a)P

22. Do Polyphenol induce mitochondrial biogenesis?

23. * Significantly different from B(a)P

24. 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

25. * Significantly different from B(a)P

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

27. * Significantly different from B(a)P

28. 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

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

30. Thank you!