No One Should Have to Choose Safety or Their Pet Help Build a Safe Place !
New Discovery May Explain Why Triple-Negative Breast Cancer Resists Chemotherapy
Guest Contributor
Triple-negative breast cancer has long been known as the most aggressive breast cancer subtype, and one of the most difficult to treat. Chemotherapy is usually the main systemic treatment, yet about half of all patients either do not respond well or eventually become resistant. A new study from Roswell Park Comprehensive Cancer Center takes a close look at why that happens and points to a potential key player in chemotherapy resistance in triple-negative breast cancer: a protein called MPP8.
This work centers on the role of MPP8 in how cancer cells handle damage to their DNA. When chemotherapy targets rapidly dividing cells, it often works by causing double-strand breaks in DNA, which are serious injuries for any cell. The newly reported research shows that MPP8 can help cancer cells repair those breaks more effectively, making them harder to kill. As a result, higher levels of MPP8 in triple-negative breast cancer cells appear to help tumors escape the full impact of chemotherapy.
The preclinical study, led by Jia Fang, PhD, an Associate Professor of Oncology in Roswell Park’s Department of Pharmacology & Therapeutics, was published in the journal Advanced Science. Using a combination of breast cancer cell lines, preclinical models and patient data, the team closely examined how MPP8 behaves inside cancer cells during chemotherapy. Their work reveals that MPP8 is not just another protein in the cell nucleus, but an active participant in how tumors survive treatment.
MPP8 is located in the nucleus, where it plays important roles in regulating DNA and gene activity. According to the research, when chemotherapy damages DNA by producing double-strand breaks, MPP8 can promote the repair process. The more MPP8 that breast cancer cells produce, the more capable they seem to be at fixing this damage. That increased repair capacity is directly linked to chemotherapy resistance because the cancer cells are better equipped to withstand the drugs that are meant to destroy them.
The study also explored what happens when the activity of MPP8 is dialed down. Suppressing MPP8 expression resensitized breast cancer cells that had become resistant, making them more vulnerable to chemotherapy again. That finding is particularly striking because it suggests a new way to improve chemotherapy effectiveness in triple-negative breast cancer. Rather than relying solely on stronger or additional drugs, targeting a specific protein that shapes how cells respond to treatment could open up a more tailored approach.
The Roswell Park team went further by identifying a new mechanism through which MPP8 promotes DNA repair. They report that MPP8 supports DNA repair using the most dominant double-strand break repair pathway in human cells. This preferred pathway is central to how cells maintain their genetic integrity. When MPP8 enhances this process in breast cancer cells, it strengthens their ability to survive chemotherapy and contributes to treatment resistance.
This mechanistic insight carries important clinical implications. If MPP8 helps tumors rely on a particular DNA repair pathway, then patients whose cancers have high MPP8 levels may be better suited for treatment strategies different from the drugs most commonly used for triple-negative breast cancer. In other words, measuring MPP8 could become part of matching patients with the therapies most likely to work for their specific tumor biology.
Dr. Fang notes that the future of treatment may lie in identifying patients based on MPP8 levels in their tumors and then using that information to guide care. This approach aligns with the broader trend toward precision oncology, where therapies are increasingly chosen based on detailed molecular features of each person’s cancer. If MPP8 status helps predict chemotherapy resistance, it could assist clinicians in deciding when to adjust a regimen or consider alternative drugs.
This study builds on more than a decade of work on MPP8 from the same research team. In 2010, Dr. Fang and colleagues published the first evidence that MPP8 can silence genes that usually suppress tumor growth. By shutting down these protective genes, MPP8 was shown to promote metastasis, the spread of cancer cells from the original tumor site to other parts of the body. That research focused on a process called epithelial-to-mesenchymal transition, in which cancer cells gain the ability to move and invade.
Since that initial discovery, the team has uncovered multiple ways in which MPP8 helps drive cancer growth. The new findings about MPP8 and chemotherapy resistance in triple-negative breast cancer add another piece to this picture. Together, the body of work portrays MPP8 as a multifaceted contributor to cancer’s aggressiveness, from helping tumors spread to enabling them to survive treatment.
The recently published study lists Rupa Kumari, PhD, a Senior Research Associate in Roswell Park’s Department of Gynecologic Oncology, as first author. The research received partial support from the Roswell Park Alliance Foundation as well as grants from the National Cancer Institute, including Roswell Park’s Cancer Center Support Grant. These sources reflect sustained investment in uncovering how and why some cancers evade standard therapies.
For people diagnosed with triple-negative breast cancer, chemotherapy resistance is more than a scientific concept. It can mean fewer options, more uncertainty and, too often, poorer outcomes. While the current study is preclinical and will need further confirmation in clinical settings, it provides a scientifically grounded rationale for exploring MPP8 as both a biomarker and a potential therapeutic target. If future trials validate these findings, testing for MPP8 expression could one day help clinicians decide which treatments are likely to be most effective for a given patient, and whether strategies that inhibit DNA repair pathways might be appropriate.
Roswell Park Comprehensive Cancer Center has a long history of contributing to advances in cancer detection and treatment, including pioneering chemotherapy research and the development of the PSA prostate cancer biomarker. Today its team continues that tradition through research efforts like this MPP8 study, with the goal of making cancer care more effective and more personalized for patients in New York State and beyond. As work continues to understand chemotherapy resistance and refine treatment approaches for triple-negative breast cancer, discoveries like this highlight the importance of looking closely at the molecular details that allow cancer cells to survive, and finding ways to turn those details into therapeutic opportunities.