A cancer-causing adaptor protein that facilitates proliferation of colorectal and cervical cancer cells could become a new target for cancer treatment, a researcher at National Cheng Kung University in Tainan City said yesterday.
Eps8, which stands for “EGF receptor pathway substrate No. 8,” was first discovered in the 1990s but its role in cancer formation was not understood at the time, said Leu Tzeng-horng (呂增宏), head of the university’s Institute of Pharmacology.
In 2007, a research team headed by Leu linked Eps8 to colorectal cancer, and it confirmed a year later that it was also associated with cervical cancer.
Eps8 is an adaptor protein and a common substrate for both the epidermal growth factor (EGF) receptor and the enzyme Src tyrosine kinase. Src not only can phosphorylate, or “activate” Eps8, but can also influence its expression, Leu said.
The team’s latest study found that Eps8 can spur the Src substrate focal adhesion kinase (FAK), which is associated with the progression of colorectal cancer.
In animal experiments, the team observed that lowering Eps8 levels resulted in decreased tumor growth, suggesting that reducing Eps8 could therefore inhibit the proliferation of cancerous cells.
Citing analyses of cancer specimens, Leu said that excessively high levels of Eps8 were seen in late-stage colorectal cancer patients, while patients with thyroid cancer, breast cancer and cervical cancer were found to have higher-than-normal levels of the substrate.
Leu said that agents that attenuate Eps8 can be used to inhibit or destroy the tumor growth of cancer cells, but human tests are still needed.