MSU Researchers Uncover How Ovarian Cancer Resists Chemotherapy — and How to Reverse It
Key Insights
MSU scientists identified the protein TPPP3 (search) as a key driver of cisplatin resistance in ovarian cancer (search) by stabilizing microtubules against chemotherapy-induced disruption.
Cancer cells with higher TPPP3 (search) levels better withstand cisplatin or carboplatin, while patients with lower TPPP3 levels lived longer and responded better to treatment.
Removing TPPP3 (search) in laboratory models significantly restored cancer cells' sensitivity to cisplatin, suggesting a new therapeutic strategy to overcome resistance.
Michigan State University researchers have identified how ovarian cancer (search) cells become resistant to cisplatin, a widely used chemotherapy drug first discovered at MSU in 1965, and have pinpointed a protein that, when blocked, can restore the drug's effectiveness. The findings, published in Cell Reports, represent a significant advance in understanding why tumors initially respond to treatment but later return stronger.
"We have learned how cancer cells adapt to chemotherapy by altering their internal structure," said Sachi Horibata, assistant professor in the Precision Health Program and Department of Pharmacology and Toxicology at the MSU College of Human Medicine and one of the lead researchers on the study. "This enables them to survive and ultimately resist treatment."
Beyond DNA Damage: The Tubulin Code
It has long been understood that cisplatin works by damaging cancer cells' DNA, but this study reveals that it also disrupts microtubules — the internal scaffolding cells rely on to survive. Rather than simply repairing DNA damage, cancer cells can reprogram what scientists call the "tubulin code," a set of structural changes that help stabilize microtubules and support survival under stress.
At the center of that process is a protein called tubulin polymerization promoting protein 3, or TPPP3 (search). The researchers found that cancer cells with higher levels of TPPP3 were better able to stabilize their internal scaffolding and withstand the effects of cisplatin or carboplatin that attempt to destroy that internal scaffold.
"TPPP3 (search) acts like a protective shield for cancer cells," Horibata said. "When we remove it, we weaken the cell's defenses and allow chemotherapy to work more effectively."
Clinical Implications and Patient Outcomes
In contrast to those with elevated TPPP3 (search), patients with lower levels of the protein lived longer and responded better to treatment. In laboratory models, removing the protein significantly restored cancer cells' sensitivity to cisplatin, suggesting a new approach to overcoming resistance. This discovery also helps explain why some patients are told they are cancer-free, only to see the disease return.
By shifting focus beyond DNA to the physical structure of cancer cells, researchers say the findings could open the door to improving existing treatments rather than replacing them.
Translating Discovery into Therapy
Researchers are now working to translate these findings into new treatment strategies, including developing drugs that target TPPP3 (search) and testing whether the protein can be used as a biomarker to identify patients at risk of developing resistance. Future studies will also examine how this mechanism affects current chemotherapy combinations and whether it plays a role in fighting other cancer types.
"This is about staying one step ahead of cancer," Horibata said. "If scientists can understand how tumors adapt to survive treatment, we can start to block that process — making existing therapies more effective, more durable and ultimately more personalized for each patient."
Broader Implications Beyond Ovarian Cancer (search)
The findings may also have broader implications. Because microtubules are essential in many healthy cells, this research could help scientists better understand some of chemotherapy's most common side effects, including nerve damage, hair loss and hearing loss.
The study included researchers from MSU, the National Institute of Neurological Disorders and Stroke at the National Institutes of Health, the Center for Cancer Research at the National Cancer Institute, and the Center for Biomedical Informatics & Information Technology at the National Cancer Institute. The work was funded by MSU, the Japan Society for the Promotion of Science, the Intramural Research Program of the National Cancer Institute, the National Institute of Neurological Disorders and Stroke, the National Heart and Lung Institute, and the Intramural Research Program of the National Institutes of Health.