Laboratory of Bacterial and Tumor Resistance
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Drug resistance is a major problem today, affecting many disciplines - microbiology, oncology, dermatology, and neurology; it reduces the effectiveness of treatment and quality of life, increases the cost of treatment, and most importantly increases mortality. As the development of new drugs is no longer sufficiently progressive due to the growth rate of resistance, it is necessary to look for alternative treatment solutions. Such an alternative may be an adjuvant - a substance that restores efficacy to old, non-functional drugs to which resistance has already developed by a known mechanism. Our laboratory is engaged in searching for new adjuvants for treating bacterial infections and cancer.
Bacterial resistance
Augmentin, a combination of amoxicillin (a β-lactam antibiotic) and clavulanic acid (an adjuvant that inhibits β-lactamases), has been used in clinical practice for more than 40 years. During this time, it has proven its efficacy, usefulness, and minimal development of resistance. Other β-lactam adjuvants soon followed. Surprisingly, however, β-lactamases inhibitors are the only adjuvants approved for adjuvant therapy these days, even though several enzymes that modify the structure of antibiotics (destructases) are known. This opens the search for new effective inhibitors of other bacterial destructases.
Resistance of eukaryotic cells
Currently, about one in five people in Western countries is treated for neurological problems such as depression, anxiety, or epilepsy. One in three of these people will eventually develop resistance to the drugs they are given. Resistance to chemotherapy drugs is a similarly serious problem and is responsible for most cancer deaths. The common denominator in these cases is usually the overproduction of transmembrane efflux pumps that reduce intracellular localization of the drug below the therapeutic dose. Thus, the active adjuvant in this case is an inhibitor of these efflux pumps.
In bacterial cells, we use nanopore sequencing of clinical isolates (1) to identify the bacterial mechanisms to eliminate antibiotics (2). We then clone the genes responsible for these resistances into a library of bacterial strains, where each strain carries a single resistance determinant (3). Then we use this library for high-throughput testing of compounds in an attempt to find those that can revert the resistant phenotype to a sensitive one in the presence of antibiotics. If such substances are found, we test their inhibitory activity on isolated recombinant enzymes (4). We then return promising substances to clinical practice to test their specificity against different enzymes of the same class and their selectivity against different antibiotic-resistant bacterial isolates (5).
In cancer cells, we focus on modulation of transmembrane efflux pump activity and NRF2 signalling pathway. We use reporter assays and a collection of cancer cell lines and their sublines resistant to chemotherapeutics. Again, our goal is to search for new adjuvants (inhibitors) to return efficacy to existing chemotherapeutics. We then validate promising inhibitors in more complex in vitro tumour models mimicking physiological tumour parameters. Specifically, these include spheroids and organoids derived from patient biopsies. We are subsequently developing systems for targeted delivery of inhibitors to tumour cells and are using these systems in vivo experiments to validate the activity of our inhibitors in mammalian cells.
