Study of BRCA-1 Mimetic Drugs in Breast Cancer Organoids
Poster #: 180
Session/Time: A
Author:
Andrew Mun, BS
Mentor:
Kan Wang, MD
Research Type: Clinical Research
Abstract
INTRODUCTION:
Breast cancer stem cells (BCSCs) are a distinct subpopulation that possesses the ability to self-renew and differentiate into various types of cancer cells, thereby maintaining tumor growth. They also have the ability to differentiate and can give rise to more specialized cancer cells. Some BCSCs can undergo epithelial-mesenchymal transition (EMT), gaining migratory and invasive capabilities that enhance metastatic potential. Their unique properties also make them resistant to conventional therapies. Research has highlighted interest in the BRCA-1 molecule due to its inhibitory role in estrogen receptor α (ER-α) activity in BCSCs by binding to the ER-α protein, thereby blocking estrogen-stimulated gene expression required for cell proliferation. Our lab has developed several compounds that mimic the function of BRCA-1. These BRCA-1 mimetics not only suppress the upregulation of ER-α activity but also overcome the drug resistance found in Tamoxifen, with little to no risk of systemic toxicity, which is an encouraging sign for future use. More importantly, these compounds inhibited activity for both antiestrogen-sensitive and antiestrogen-resistant breast cancer cells. These findings reveal a novel class of ER-α modulators that employ a distinct mechanism from conventional antiestrogens, such as Tamoxifen and Fulvestrant. Moreover, these mimetics can treat Tamoxifen-sensitive and non-sensitive cells. Our lab will generate organoids from the MCF-7 cancer stem cells, which are 3d structures mimicking the complex microenvironment of real tumors present in the human body. Once the organoids are generated, we will use our BRCA-1 mimetics on the organoids to assess their efficacy in inhibiting cell growth.
METHODS:
We cultivated MCF-7 cancer cells and used this cell line to create MCF-7 CSCs. These cells were grown in an anchorage-free environment using stem cell media with DMEM. Mammospheres created from stem cells were collected and combined with VitroGel®, a synthetic ECM-like hydrogel, to generate 3D organoids. We also incorporated TGF-β1 to study the efficacy of our compounds in inducing stem cell proliferation and differentiation. We formed one droplet as the control, which only contained the cell suspension and hydrogel. Another droplet was formed with the addition of TGF-β1, a growth factor that assists stem cells in undergoing EMT while differentiating into organoids. The first group of plates is treated with estradiol in combination with the drug, the second group receives the drug alone without estradiol, and the final group serves as a control, containing neither estradiol nor the drug. We will measure the size of the mammospheres after several weeks. E-cadherin and N-cadherin will be used as histochemical biomarkers of differentiation, with E-cadherin marking epithelial cells and N-cadherin marking mesenchymal cells. The relative expression of these markers is considered the gold standard for assessing EMT and cellular differentiation.
RESULTS:
The study is ongoing. Organoid generation is being optimized to yield viable, reproducible models suitable for testing our BRCA-1 mimetics.
CONCLUSION:
We hope to establish MCF-7 organoids as a platform for subsequent testing and analysis of BRCA-1 mimetic compounds, with the 3D structure of the organoids expected to provide more physiologically relevant insights into drug activity within the human body.
Breast cancer stem cells (BCSCs) are a distinct subpopulation that possesses the ability to self-renew and differentiate into various types of cancer cells, thereby maintaining tumor growth. They also have the ability to differentiate and can give rise to more specialized cancer cells. Some BCSCs can undergo epithelial-mesenchymal transition (EMT), gaining migratory and invasive capabilities that enhance metastatic potential. Their unique properties also make them resistant to conventional therapies. Research has highlighted interest in the BRCA-1 molecule due to its inhibitory role in estrogen receptor α (ER-α) activity in BCSCs by binding to the ER-α protein, thereby blocking estrogen-stimulated gene expression required for cell proliferation. Our lab has developed several compounds that mimic the function of BRCA-1. These BRCA-1 mimetics not only suppress the upregulation of ER-α activity but also overcome the drug resistance found in Tamoxifen, with little to no risk of systemic toxicity, which is an encouraging sign for future use. More importantly, these compounds inhibited activity for both antiestrogen-sensitive and antiestrogen-resistant breast cancer cells. These findings reveal a novel class of ER-α modulators that employ a distinct mechanism from conventional antiestrogens, such as Tamoxifen and Fulvestrant. Moreover, these mimetics can treat Tamoxifen-sensitive and non-sensitive cells. Our lab will generate organoids from the MCF-7 cancer stem cells, which are 3d structures mimicking the complex microenvironment of real tumors present in the human body. Once the organoids are generated, we will use our BRCA-1 mimetics on the organoids to assess their efficacy in inhibiting cell growth.
METHODS:
We cultivated MCF-7 cancer cells and used this cell line to create MCF-7 CSCs. These cells were grown in an anchorage-free environment using stem cell media with DMEM. Mammospheres created from stem cells were collected and combined with VitroGel®, a synthetic ECM-like hydrogel, to generate 3D organoids. We also incorporated TGF-β1 to study the efficacy of our compounds in inducing stem cell proliferation and differentiation. We formed one droplet as the control, which only contained the cell suspension and hydrogel. Another droplet was formed with the addition of TGF-β1, a growth factor that assists stem cells in undergoing EMT while differentiating into organoids. The first group of plates is treated with estradiol in combination with the drug, the second group receives the drug alone without estradiol, and the final group serves as a control, containing neither estradiol nor the drug. We will measure the size of the mammospheres after several weeks. E-cadherin and N-cadherin will be used as histochemical biomarkers of differentiation, with E-cadherin marking epithelial cells and N-cadherin marking mesenchymal cells. The relative expression of these markers is considered the gold standard for assessing EMT and cellular differentiation.
RESULTS:
The study is ongoing. Organoid generation is being optimized to yield viable, reproducible models suitable for testing our BRCA-1 mimetics.
CONCLUSION:
We hope to establish MCF-7 organoids as a platform for subsequent testing and analysis of BRCA-1 mimetic compounds, with the 3D structure of the organoids expected to provide more physiologically relevant insights into drug activity within the human body.