SUM159 cells are a specific line of human cells used in scientific research to study a challenging form of breast cancer. These cells provide a consistent and reproducible model system, allowing scientists to investigate the complex biology of the disease. Their use is widespread in efforts to understand tumor growth, spread, and resistance to treatment, and to test new therapeutic compounds before they can be considered for human trials.
Origin and Identification of SUM159 Cells
The SUM159 cell line, also known as SUM159PT, was established from a primary tumor of a patient with an aggressive type of breast cancer. These cells are derived from what is classified as an anaplastic carcinoma of the breast. This type of cancer is characterized by cells that have lost their distinct structural and functional features, appearing disorganized and multiplying rapidly. The development of this cell line provides a window into the biology of such aggressive tumors.
This cell line is a model for triple-negative breast cancer (TNBC). This classification means the cancer cells lack three specific receptors that are common targets for many current breast cancer therapies: the estrogen receptor (ER), the progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). The absence of these receptors makes TNBC particularly difficult to treat, as it does not respond to hormonal therapies or drugs that target HER2.
Because SUM159 cells are estrogen independent, they can grow and form tumors without the influence of estrogen, mimicking the clinical behavior of these challenging cancers. Their ability to grow robustly in laboratory settings, both in culture dishes and as tumors in animal models, makes them a practical tool for scientists developing new treatments.
Key Biological Properties
SUM159 cells possess distinct biological and genetic features, making them a focus of study. Genetically, they harbor several mutations commonly found in aggressive cancers. These include mutations in the TP53 gene, a tumor suppressor, and the PIK3CA gene, which is involved in cell growth and survival. They also show a mutation in the HRAS gene, which can drive uncontrolled cell proliferation.
In addition to their receptor status, SUM159 cells display features of a “basal-like” cancer, expressing specific proteins called cytokeratins 5, 6, 14, and 18, which are markers associated with this particular classification.
One of the most notable properties of SUM159 cells is their invasive nature. They can move through a protein matrix designed to mimic body tissue, reflecting the potential to spread to other parts of the body. This invasive capability is linked to a process known as the epithelial-to-mesenchymal transition (EMT), where cancer cells gain migratory and invasive properties. The expression of the protein vimentin and the lack of E-cadherin in SUM159 cells are molecular indicators that this transition has occurred.
The SUM159 cell population contains a subset of cells with the characteristics of cancer stem cells (CSCs). These cells are thought to be responsible for tumor initiation, recurrence, and resistance to therapy. The presence of these CSCs within the SUM159 line allows researchers to study the specific behaviors of this resilient cell population.
Applications in Breast Cancer Research
Scientists use SUM159 cells as a versatile model system to investigate the fundamental processes that drive aggressive breast cancer. Researchers employ these cells to dissect the complex molecular pathways responsible for tumor growth, survival, and metastasis. By manipulating genes or exposing the cells to various stimuli, scientists can identify the specific proteins and signaling networks that contribute to the cancer’s aggressive behavior.
A primary application of the SUM159 cell line is in the screening and evaluation of potential new anti-cancer drugs. Because these cells represent a treatment-resistant form of breast cancer, they are an ideal platform for testing the effectiveness of novel therapeutic compounds. For instance, studies have shown that SUM159 cells are sensitive to a class of drugs called BET bromodomain inhibitors, which can induce cell death and inhibit proliferation by targeting key genetic regulators.
The study of drug resistance is another area where SUM159 cells are frequently used. Researchers can expose the cells to existing chemotherapy agents to understand how they develop resistance over time. This allows for the identification of the molecular changes that enable cancer cells to survive treatment, offering clues for designing strategies to overcome this resistance.
The presence of cancer stem cells within the SUM159 line makes them particularly useful for research into tumor recurrence. Scientists can isolate this specific subpopulation of cells to study their unique properties, such as their ability to self-renew and generate new tumors. This research is aimed at developing therapies that specifically target and eliminate CSCs, which could lead to more durable responses to treatment.
Significant Discoveries from SUM159 Cell Studies
One area of discovery involves understanding the role of the tumor microenvironment, which is the complex ecosystem of cells and molecules surrounding a tumor. Studies have demonstrated that interactions between SUM159 cells and other cell types, such as mesenchymal stem cells found in bone marrow, can enhance the cancer stem cell population, making the tumor more aggressive.
Specifically, this research revealed a communication loop involving signaling molecules called cytokines. The cancer cells and mesenchymal stem cells were found to release substances like IL-6 and CXCL7, which act on each other to promote the survival and proliferation of the cancer stem cells. This discovery highlights that targeting the interaction between cancer cells and their surrounding environment could be a promising therapeutic strategy.
Other findings relate to the identification of new therapeutic targets. For example, studies on SUM159 cells have explored their energy production processes, known as metabolism. Research has shown that certain compounds can disrupt the function of mitochondria, the cell’s powerhouses, leading to the death of the cancer cells. One study identified that a compound called TR-57 could inhibit mitochondrial activity and the expression of proteins necessary for energy production in SUM159 cells.