Artificial saliva containing sugarcane protein helps protect the teeth of patients with head and neck cancer

(Press-News.org) An artificial saliva in the form of a mouthwash, produced with the CANECPI-5 protein extracted from sugarcane and modified in a laboratory, can aid in treating teeth in patients with head and neck cancer. In these cases, radiotherapy very close to the mouth can destroy salivary glands and compromise saliva production, which is essential for controlling bacteria and disease.

According to research conducted at the Bauru School of Dentistry at the University of São Paulo (FOB-USP) in Brazil, CANECPI-5 forms a protective “shield” for the teeth, guarding the enamel against weakening acids found in juices, alcoholic beverages, and even stomach acids. The results were published in the Journal of Dentistry. 

The study was conducted during Natara Dias Gomes da Silva’s doctoral studies at FOB-USP. She collaborated with researchers from the Federal University of São Carlos (UFSCar), also in Brazil; the University of California in San Francisco, in the United States; and Yonsei University College of Dentistry, in South Korea.
    
The work is part of the Thematic Project “Modulation of acquired pellicle to control dental mineral loss: unveiling mechanisms to make therapies possible”, which is coordinated by Professor Marília Afonso Rabelo Buzalaf from FOB-USP. 

“We tested the mouthwash developed with CANECPI-5 by applying this solution to small pieces of animal teeth once a day for one minute. Based on these results, we’ll conduct further research so that we can think about applications of this product,” adds Silva, the first author of the article.

“This is the first product that uses the concept of acquired pellicle [a thin protective layer that quickly forms on the tooth surface] to treat xerostomia, which is the sensation of a dry mouth caused by a lack of saliva. We use substances that will reformulate the composition of the proteins that bind to the teeth,” explains Buzalaf.

“We’ve developed a process in which CANECPI-5 binds directly to tooth enamel, helping to make teeth more resistant to the action of acids produced by bacteria,” Silva points out.

The data published in the article showed that the CANECPI-5 protein is most effective when combined with fluoride and xylitol. In these tests, the artificial saliva spray significantly reduced bacterial activity and tooth demineralization – the process by which teeth lose calcium and phosphate, making them more susceptible to cavities. 

This discovery is significant because patients undergoing treatment for head and neck cancer do not yet have access to a specific product on the market that can help combat and treat the most aggressive cavities that develop after radiation therapy.

“Artificial saliva improves the sensation of dry mouth and sores. This helps with discomfort and also combats bacteria. 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,” adds Buzalaf.

The patent for the CANECPI-5 protein was filed a few years ago. According to the researchers, the challenge now is to scale up in partnership with companies interested in the technology so that the artificial saliva can be produced.

“We’ve already tested the solution as a mouthwash, gel, and orodispersible film, which is a type of plastic that’s placed on the tongue and dissolves, releasing the protein. We’ve tested it in several vehicles and found that CANECPI-5 works very well in all of them. We’ll continue testing other technologies within the Thematic Project to use not only this protein, but others as well,” says Buzalaf.

Regarding the discovery of CANECPI-5

According to Flávio Henrique Silva, a professor in the Department of Genetics and Evolution at UFSCar, who worked on developing the CANECPI-5 protein, the work with cystatins (a family of proteins involved in various biological processes) is linked to research carried out under the Sugarcane Genome Project (SUCEST, FAPESP). His laboratory is part of that project.

“At that time, our group identified and produced, in a recombinant form in bacteria, the first cystatin from sugarcane. We named it CANECPI-1. We then identified and produced five other cane cystatins, including CANECPI-5, which had potent inhibitory activities against cysteine peptidases, which are its target enzymes. Throughout our work, we noticed that this protein bound strongly to smooth surfaces, such as the quartz cuvettes used in activity measurements. This led us to conduct tests in partnership with Professor Marília Buzalaf on the binding of the protein to tooth enamel.”

According to the researchers, the discovery that CANECPI-5 protects tooth enamel while also regulating the oral microbiota makes it a highly promising molecule for dentistry research.

“CANECPI-5 has also been used in the work of other colleagues in the field of dentistry, particularly involving periodontitis. We also have a collaborative project with a colleague from the Federal University of Uberlândia, using subcutaneous sponge implants in mice, which has shown that it’s capable of reducing inflammation and promoting angiogenesis [the formation of new blood vessels] and fibrinogenesis [the formation of fibrin, a protein essential for blood clotting], important processes in tissue repair, making it a candidate molecule for use in wound healing,” Silva points out.

Next steps 

Within the Thematic Project, the researchers will continue trying to understand how CANECPI-5 interacts with other substances. 

According to Buzalaf, one possible avenue is to study CANECPI-5 fused with a peptide derived from statherin, a protein found in saliva, to see if the new hybrid protein is more effective against the acids that weaken teeth when they come from the stomach. Another possible avenue is to try to understand how to combat periodontal disease.

“Another aspect of the Thematic Project is to associate CANECPI-5 with vitamin E because this vitamin acts as a carrier, bringing the protein into contact with the tooth. We imagine that this could facilitate the application of the product directly by the patient at home,” says the researcher.

About São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

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