Scientists develop unique tantalum complexes with anticancer effects

Molecular structure of one such tantalum complex. Authors: Pavel Štarha, Zdeněk Trávníček, RCPTM
Monday 18 March 2019, 13:00 – Text: Martina Šaradínová

Tantalum complexes could aid in combatting tumorous diseases. RCPTM scientists have developed complexes of this transition metal which show significant anticancer effects and reduced toxicity against healthy cells. These complexes have just been protected by a patent.

Tantalum has been known to date as a material used in medicine for implants, surgical instruments, etc. It has also found its application in the electrotechnical industry as a component for capacitors. Researchers from the RCPTM group Biologically Active Complexes and Molecular Magnets, led by Prof Trávníček, have deployed tantalum for developing organometallic complexes that show anticancer activity in relation to four different types of tumours.

“The results of the study on cellular models encouraged our researchers to carry out toxicity tests on laboratory animals. These confirmed strong cytotoxicity in cancer cells, but low cytotoxicity in healthy cells, which represents a great potential for practical applications,” explained Prof Trávníček.

The anticancer effects of the complexes have been proved in relation to bone cancer (osteosarcoma), colorectal cancer, ovarian cancer, and cisplatin-resistant ovarian cancer, cisplatin being a commonly used chemotherapy drug. “However, it is important to emphasise that the journey to therapeutic applications will still be long, despite the very positive initial research results. Such complexes must undergo a complex procedure of pre-clinical and clinical tests,” added a co-author of the study, Prof Zdeněk Dvořák.

It is the first time Olomouc scientists have selected tantalum for preparing organometallic complexes for anticancer activity. Previously, they focused on platinum- or gold-based complexes. Another two platinum group metals—osmium and iridium—have recently been of interest to researchers worldwide, achieving promising results. “We made an assumption that tantalum complexes could work on a similar basis. It proved it right. Chance favours the prepared mind,” said Prof Trávníček.

The novel complexes are protected by the patent Dichloro-complexes of tantalum; the method of their preparation, and their use in preparation of drugs for cancer treatment (CZ 307 696 B6). “The national patent office evaluated not only the originality of the invention but also its potential therapeutic applications. The patent that has just been granted is based on a pilot study carried out by the same research team, and published in the prestigious journal Chemical Communication,” explained one of the co-authors, Pavel Štarha. He added that the research is ongoing, also in collaboration with partner institutions such as the Institute of Clinical Sciences, University of Birmingham and the Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences in Brno.

Thanks to the research results of Prof Trávníček’s team, Palacký University has managed to obtain 15 Czech patents and two European ones in the past decade. These patents secure legal protection for potential application of biologically active complexes as chemotherapy drugs or against inflammatory diseases.