Effects of Extracellular Matrix Rigidity on the Sensitivity of the Aryl Hydrocarbon Receptor in Breast Cancer Cells
Open Access
- Author:
- Pezzulo, Joshua Daniel
- Area of Honors:
- Chemical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Wayne Roger Curtis, Thesis Honors Advisor
Esther Gomez, Thesis Supervisor - Keywords:
- mcf7
extracellular matrix
breast cancer
cyp1a1
ahr
immunofluorescence
western blot
dim
cells
emt
epithelial
mesenchymal
transition
mts
cruciferous
vegetables
indole
polyacrylamide - Abstract:
- The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor typically found in the cytoplasm of mammalian cells. Previous studies have described the essential role of AhR in the normal functioning of cellular processes such as proliferation, migration, and apoptosis, as well as, activation of the cytochrome P450 enzyme CYP1A1. AhR is expressed at high levels in many cancerous cells, including the MCF7 breast cancer line. The stiffness associated with the extracellular matrix also regulates many cellular functions. Typically, an increased extracellular matrix stiffness is associated with breast cancer. While there has been extensive work on the role of AhR on the function of normal cellular processes, there has yet to be any investigation into the effects of extracellular matrix rigidity on the expression and sensitivity of the AhR. Here, MCF7 cells were cultured on functionalized polyacrylamide (PA) hydrogels to mimic the mechanical environment of mammary cells with stiffnesses ranging from 300 Pa (normal mammary epithelial tissue) to 6300 Pa (cancerous breast tissue). The cells were treated with 3,3’-diindolylmethane (DiM; 30µM), an AhR agonist found in cruciferous vegetables that has been shown to have anti-carcinogenic properties, for various lengths of time (0, 24, 48, 72 hours) in addition to a dimethyl sulfoxide (DMSO, 1 mg mL-1) control. Localization of both AhR and CYP1A1 were observed using immunofluorescence techniques. Expression of AhR at the protein level was monitored by Western blot. Breast cancer cells cultured on 6300 Pa hydrogels appeared to have the highest expression of AhR. When treated with DiM, AhR expression appears to quantitatively decrease. By modulating the activation of AhR either through an anticarcinogenic ligand or a novel drug, a treatment for or reduction of metastasis in malignant breast cancer could possibly be achieved.