1. Companion PowerPoint slide set Obesity-associated breast cancer risk: a role for epigenetics?
This teacher slide set was created by Dana Haine, MS, of the UNC Center for Environmental Health and Susceptibility, which is funded by the National Institute of Environmental Health Sciences (P30-ES010126).

2. Dr. Liza Makowski Studies Basal-like Breast Cancer (BBC)
Aggressive cancer
No specific drug therapies
Short survival time if it spreads beyond breast tissue (metastasis)
More prevalent in young pre-menopausal women
More prevalent in African Americans
Obesity is a risk factor for all breast cancers

3. Obesity causes BBC tumors to form at a faster rate compared to lean mice
C3(1)-Tag mice – BBC mouse model – mice are genetically identical and are highly representative of human BBC.
until tumor formation
Number of weeks
Fat-fed (Lean)
Fat-fed
(obese)

4. Cross-section of mammary (milk) duct

5. Inside (lumen)
of milk duct
Label epithelial cells, fat cells and fibroblasts on the diagram below:

6. Adipocytes (Fat cells)
Fibroblasts
Stroma of
mammary tissue
Epithelial Cells of Milk Duct
Inside (lumen)
of milk duct
Immune cells are also present but are not shown in order to simplify schematic of the stroma.

7. microenvironment What does this image have to do with cancer?
Soil provides microenvironment to a germinating seed
Image source: Wikimedia.org
microenvironment

8. Cancer & the microenvironment
The microenvironment (“soil”) surrounding a cell (“seed”) plays a role in tumor formation.
HEALTHY CELL CANCER CELL
Liza Makowski:
“How does obesity alter the microenvironment in breast cancer?”

9. Cell to cell communication HGF-cMET paracrine signaling
C-met receptor
Hepatocyte growth factor is a molecule known to play crucial roles during development and wound healing. It is secreted by the fibroblasts present in the stroma of tissues and acts on the epithelial cells of that tissue. However, we also know that HGF is up regulated during breast cancer progression.
HGF has a single receptor called cMET, once HGF binds to cMET, in the context of cancer we know that during the invasive stages it induces a wide variety of cellular pathways for example………
Adapted from Melissa Troester/Patricia UNC

10. Cell to cell communication HGF-cMET paracrine signaling
cMET receptor
Promotes Cell Division
Promotes motility (leads to Metastasis)
Promotes growth of blood vessels to supply tumor
Prevents cell death
HGF
C-met P
Hepatocyte growth factor is a molecule known to play crucial roles during development and wound healing. It is secreted by the fibroblasts present in the stroma of tissues and acts on the epithelial cells of that tissue. However, we also know that HGF is up regulated during breast cancer progression.
HGF has a single receptor called cMET, once HGF binds to cMET, in the context of cancer we know that during the invasive stages it induces a wide variety of cellular pathways for example………
Melissa Troester/Patricia UNC

11. Obesity increases levels of HGF mRNA and protein in normal mammary tissue* *
Sundaram, S., Makowski, L., et. al. Cancer Prevention Research (Under Review, 2012)

12. Ex vivo cell culture model
Isolate
Fibroblasts
Culture
Fibroblasts
Measure
Lean Mice
HGF Secretion
Normal
Cell Division
HGF Secretion
Cancer-
associated
Obese Mice
C3(1)-Tag mice – BBC mouse model – mice are genetically identical.
HGF Secretion
HGF Secretion

13. HGF secretion in cultured cells

14. Isolate Culture HGF Fibroblasts Fibroblasts Secretion Lean Mice
Normal
Cancer-
associated
Obese Mice

15. Analysis of c-Met protein levels in BBC tumor cell line
Control
Phospho-c-Met
BBC Tumor cell line
BBC Tumor cell line + CM
BBC Tumor cell line + mHGF

16. “How does obesity alter the microenvironment in breast cancer?”
c-Met
activation
Signal
HGF
Secretion
Epithelial
cell
Cancer
formation
Fat cell
Fibroblast
Hypothesis regarding “signal” from fat cells: increased triglycerides, turn on inflammatory response, triggers fibroblasts to secrete HGF.
Microenvironment
Conclusion: growth factor signaling pathway (HGF/cMet) was upregulated with obesity.