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Background: Cancer continues to be the second leading cause of death worldwide, with colorectal cancer (CRC) being the third most common type. Despite significant advances in cancer therapies, the current treatment of CRC remains suboptimal. In addition, the effectiveness of available chemotherapeutic drugs such as 5-Fluorouracil (5-FU) is limited by CRC-acquired resistance. Methods: In this study, we provide innovative approaches employed in synthesizing four novel nucleobase analogs. Equally, we describe the effects of these compounds on proliferation, migration, aggregation, and adhesion of 5-FU-sensitive (HCT116) and -resistant (5-FU-R-HCT116) human CRC cells. In either cell type, our synthesized novel analogs significantly inhibited cell viability in a concentration- and time-dependent manner. This highlights the higher potency of these novel analogs. In addition, these compounds attenuated migration and adhesion of both cell types while they promoted homotypic cell-cell interaction. Results: These changes were reflected by the downregulation of matrix metalloproteases (MMP-2 and MMP-9). Furthermore, our analogs exhibited potent anti-angiogenic activity in vivo. Conclusion: These novel nucleobase analogs reduced the level of secreted vascular endothelial growth factor (VEGF) and nitric oxide (NO) production in both 5-FU-sensitive and -resistant CRC cells. Taken together, our data highlight the potential chemotherapeutic properties of our novel analogs against CRC, including the 5-FU-resistant form.

The smallest concentrations of heavy metal ions can be harmful to both the environment and human health. They are non-biodegradable and can accumulate all along the food chain, thus their onsite monitoring and removal is of great importance. In this work, a novel material based on (3-aminopropyl) triethoxysilane (APTES) coated iron oxide (Fe3O4) nanoparticles functionalized with guanine hydrazide (GH) was elaborated. Fourier transform infrared spectroscopy, energydispersive X-ray analysis and X-ray diffraction were used to control the synthesis and functionalization steps of the nanoparticles. The morphology and particle size were studied by scanning electron microscopy. Spherical nanoparticles with an average diameter of 45 nm were obtained. A boron-doped diamond electrode coated with GH-APTES-Fe3O4 nanoparticles was used to evaluate the electrochemical interaction of some divalent heavy metal ions with guanine hydrazide. Adsorption isotherms were investigated electrochemically and it was shown that the adsorption capacity of the nanoparticles towards heavy metals decreased in the following order: Cu 2+ > Pb 2+ > Cd 2+ . Moreover, the signals generated by square wave voltammetry exhibited two distinct linear response ranges; the first linear plot lies in the range of 0.209 to 1.03 μM with a sensitivity of 171.6 μA/μM for Cu (II), 0.232 to 0.809 μM with a sensitivity of 156 μA/μM for Pb (II) and 0.483 to 4.97 μM with a sensitivity of 101.4 μA/μM for Cd (II). Furthermore, an excellent reproducibility was achieved with relative standard deviation (RSD) values of 4%, 5% and 10% respectively over five independent measurements.

In this work the interaction characteristics of nucleobases with As(III) are studied. Novel materials consisting of magnetic nanoparticles (MNPs) functionalized with adenine hydrazide (AH), guanine hydrazide (GH) and uracil hydrazide (UH) were elaborated. The adsorption isotherms were investigated electrochemically and it was shown that the adsorption capacity of the nanoparticles towards arsenic (III) increased in the following order: AH