Experiments with gold and silver compounds showed antiproliferative activity in selected tumor cells
How to treat skin cancer, the most common among humans? Its incidence is increasing throughout the world, it mainly affects people with light skin, eyes and hair and its main cause is exposure to ultraviolet rays emitted by the sun. Centered on a common skin tumor, cutaneous squamous cell carcinoma, a project developed by pharmaceutical company Tuany Cândido aims to discover drugs for topical use that enable the control of this tumor.
The research is guided by doctor Carmen Silvia Passos Lima, coordinator of the Cancer Genetics Laboratory and professor of the Clinical Oncology discipline at the Department of Clinical Medicine, at the Faculty of Medical Sciences (FCM) at Unicamp. The study, at doctoral level, divided into three main stages, proved to be so promising that it was already awarded in its first phase as the best poster at the 18th edition of the International Conference on Biological Inorganic Chemistry (ICBIC ), held this year in Florianópolis.
Highly multidisciplinary, the work presented also had as co-authors researchers Ana Lucia Tasca Gois Ruiz and Sirlene Valério Tinti, from the Pharmacology and Toxicology Division of the Multidisciplinary Center for Chemical, Biological and Agricultural Research (CPQBA); Pedro Paulo Corbi and Camila Abbehausen, from the Department of Inorganic Chemistry at the Institute of Chemistry (IQ); and João Ernesto de Carvalho, from the Faculty of Pharmaceutical Sciences (FCF), all from Unicamp.
The first part of the research, carried out in the CPQBA and IQ laboratories and which gave rise to the poster “Gold, Palladium and Silver Metallic Complexes in the Treatment of Skin Squamous Cell Carcinoma”, studied the action of four metallic complexes of gold, palladium and silver, previously selected, in the treatment of tumor cells from different organs, cultivated in CPQBA, so that their activities on them could initially be verified. Subsequently, with the same purpose, cells from squamous cell carcinomas of the pharynx and tongue were subjected to the same procedure, as they were closer to the objective of the work, which is the treatment of cutaneous squamous cell carcinoma.
In this part of the research it was found that two of the metal complexes used - one made of gold and the other made of silver - showed antiproliferative activity in the selected tumor cells, leading to the death of cancer cells and preventing the emergence of others.
The next step, now to be carried out at the FCM Cancer Genetics Laboratory, will involve the isolation of cells from fragments of the studied carcinoma from patients at the Unicamp HC so that they can be tested with the two complexes that have proven to be most effective.
Cutaneous squamous cell carcinoma often affects areas such as the nose and lips. Although these tumors generally do not give rise to metastases, they can cause very serious local effects, leading to the loss of the nose or lips. Carmen explains that, as the removal of this carcinoma is surgical, “our immediate objective is not to eliminate this intervention, although that may become possible, but to arrive at a drug for topical use capable of greatly reducing the extent of the tumor so that the Surgical resection leaves as few aesthetic and functional sequelae as possible.”
Steps
The project also includes two more stages. The next one, also underway at CPQBA, guided by veterinarian Karin Costa and also supervised by professor João Ernesto, involves the induction of the tumor in mice to carry out topical treatment with the same two metal complexes. This treatment, which constitutes the third phase of the study, involves the application, in the tumor region of the animals, of a bacterial cellulose membrane that adheres to the skin, impregnated with metal complexes, which is being developed at UNIARA. In this single stage, the researcher does not have direct participation, as in the others she carried out the work herself, duly guided by professionals in the respective areas, which the supervisor considers important for her training.
The idea, explains the teacher, was to bring together knowledge from several areas. Case of promising complexes for combating cancer cells, whose preparations were developed at IQ by professors Pedro Paulo and Camilla and their teams; of cell lines cultivated in CPQBA and experiments with vitro Professor Ana Lúcia and technician Sirlene from the same unit, whose laboratories were provided for research supervised by Professor João Ernesto, from FCF; from the engineering course staff at the University of Araraquara, UNIARA, who under the supervision of professor Wilton Rogerio are developing the adhesive, a bacterial cellulose membrane to be used for the adequate release of the chemotherapy drug into the skin.
The teacher highlights the fundamental importance of each of the stages, first allowing to determine the efficiency vitro of the complexes selected to combat tumor cells, which will then be applied to measure their actions and toxicity in the animal model, when the possibilities of using them in humans will then be verified, which will probably remain for a postgraduate project.