For many patients surviving head and neck cancer, the battle does not end with the completion of radiotherapy. While the treatment is designed to eliminate tumors, the radiation often causes collateral damage to the salivary glands, leading to a condition known as xerostomia—a chronic, severe dryness of the mouth.
Without the natural lubrication and protective properties of saliva, the oral environment shifts. Saliva is not merely a lubricant; it is a complex biological fluid that regulates bacteria and buffers the mouth against acids. When it vanishes, teeth become rapidly vulnerable to aggressive decay and severe cavities, creating a secondary health crisis for cancer survivors.
Now, a multidisciplinary team of researchers has developed a promising solution: an artificial saliva made from sugarcane protein that acts as a biological shield for tooth enamel. The study, published in the Journal of Dentistry, suggests that a lab-modified protein called CANECPI-5 can bind directly to the teeth to prevent the mineral loss that typically follows radiation therapy.
The research was led by the Bauru School of Dentistry at the University of São Paulo (FOB-USP) in Brazil, in collaboration with the Federal University of São Carlos (UFSCar), the University of California in San Francisco, and Yonsei University College of Dentistry in South Korea. By mimicking the body’s natural defenses, the team hopes to provide a dedicated treatment for a patient population that currently has few options for preventing post-radiation dental collapse.
Mimicking the Body’s Natural Defense
To understand how this new treatment works, one must understand the “acquired pellicle.” This represents a thin, protective layer of proteins and glycoproteins that forms almost instantly on the surface of the teeth. In a healthy mouth, this pellicle acts as a primary barrier, regulating how minerals enter and abandon the enamel and preventing acids from dissolving the tooth structure.
In patients with xerostomia, this protective layer is compromised or absent. Professor Marília Afonso Rabelo Buzalaf, who coordinated the project at FOB-USP, explains that the goal was to reformulate the proteins that bind to the teeth to restore this lost protection.
The researchers utilized CANECPI-5, a protein derived from sugarcane, to create a synthetic version of this shield. During the study, the solution was applied to small sections of animal teeth for one minute once per day. The results showed that the protein binds strongly to the enamel, making the teeth significantly more resistant to acids produced by bacteria, as well as external acids found in alcohol, fruit juices, and stomach acid during reflux episodes.
The team discovered that the efficacy of the artificial saliva made from sugarcane protein increased when combined with fluoride, and xylitol. This combination not only slowed the process of demineralization—where the teeth lose essential calcium and phosphate—but also reduced overall bacterial activity in the oral cavity.
Closing the Gap in Cancer Care
While various “artificial saliva” products exist on the market, most are designed primarily to alleviate the uncomfortable sensation of dry mouth rather than to treat the underlying pathological decay. For cancer patients, the loss of saliva often leads to “radiation caries,” a rapid and devastating form of tooth decay that can lead to total tooth loss.
“Artificial saliva improves the sensation of dry mouth and sores. This helps with discomfort and also combats bacteria,” says Prof. Buzalaf. “In some cases, the use of this type of product is only for a short time. In others, it’s permanent, because many individuals lose the ability to produce saliva.”
Because there is currently no dedicated pharmaceutical product specifically designed to treat these severe, radiation-induced cavities, the development of a protein-based shield represents a significant shift toward preventative dental medicine for oncology patients.
An Accidental Discovery from the Sugarcane Genome
The path to this dental breakthrough began not in a clinic, but in a genetics lab. The protein was discovered as part of the Sugarcane Genome Project (SUCEST), funded by FAPESP. Researchers were studying cystatins—a family of proteins involved in various biological processes—when they identified CANECPI-5.
Flávio Henrique Silva, a professor in the Department of Genetics and Evolution at UFSCar, notes that the team first produced the protein in a recombinant form using bacteria. While testing its inhibitory activities against certain enzymes, they noticed a peculiar physical property: the protein adhered strongly to smooth surfaces, including the quartz cuvettes used in the lab.
This observation sparked the partnership with the Bauru School of Dentistry to see if that same binding capability could be applied to human tooth enamel. Beyond dentistry, the protein’s ability to reduce inflammation and promote the formation of new blood vessels (angiogenesis) has led to further exploration of its use in wound healing and the treatment of periodontitis.
From the Lab to the Pharmacy
The CANECPI-5 protein has already been patented, and the research team is currently exploring the most effective ways to deliver the treatment to patients. Because the protein is versatile, it has shown success in several different formats:
- Mouthwash: A liquid rinse for daily application.
- Gels: A more viscous application for longer contact time with the enamel.
- Orodispersible films: Small, dissolvable plastic-like films placed on the tongue that release the protein slowly.
The next phase of development involves scaling up production through partnerships with commercial manufacturers. The team is investigating a “hybrid” version of the protein combined with a peptide derived from statherin—a natural saliva protein—to enhance protection against stomach acids.
Researchers are also testing the association of CANECPI-5 with Vitamin E. In this model, the vitamin acts as a carrier, helping the protein reach the tooth surface more efficiently, which would allow patients to apply the treatment easily at home.
| Feature | Function/Detail |
|---|---|
| Origin | Lab-modified sugarcane protein (Cystatin) |
| Primary Mechanism | Binds to enamel to recreate the acquired pellicle |
| Key Benefit | Protects against bacterial and gastric acids |
| Target Population | Patients with radiotherapy-induced xerostomia |
| Delivery Methods | Mouthwash, gel, and dissolvable films |
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Patients undergoing cancer treatment should consult their oncology and dental teams before starting any new oral care regimen.
The research team will continue to refine the protein’s interaction with other compounds and evaluate its potential in preventing periodontal disease. The next confirmed checkpoint for the project is the pursuit of commercial partnerships to transition the patented protein from a laboratory setting into clinical trials and eventual market availability.
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