Novel Organomineral Complex with Prolonged Antitumor Action.

Blocking the MAPK pathway is a strategy to stop cancer cells proliferation. Despite all the successes, the acquisition of drug resistance by cells, as well as the mutational status of the downstream protein KRAS, reduces the tumor response to therapy. Ribonuclease binase from Bacillus pumilus is among the agents that block this pathway through direct interaction with EGFR and RAS. The present study is aimed at the design, optimization, and characterization of a novel complex based on antitumor binase immobilized on microgranular clinoptilolite-containing rock to ensure its prolonged release in the gastrointestinal tract. A set of modern methods including transmission electron microscopy, scanning electron microscopy, and computed tomography was used to characterize the granularity, porosity and elemental composition of the carrier. The size of binase particles, measured by atomic force microscopy at 7 nm, allows enzyme penetration into meso- and macropores of the carrier. Calorimetric results confirm that binase is stable at high temperatures, even exceeding those in the body, and retains catalytic activity in the model fluids of the gastrointestinal tract. The parameters for processing a natural clinoptilolite-containing rock and the conditions for binase sorption were selected. The gradual release of the enzyme from the carrier lasts over 20 h, which provides cytotoxicity towards human adenocarcinoma cells during movement through the gastrointestinal tract. Thus, for the first time a promising long-acting complex with antitumor and detoxifying properties was successfully created.