Correction: Dulski et al. An Organic-Inorganic Hybrid Nanocomposite as a Potential New Biological Agent. Nanomaterials 2020, 10, 2551.

In the original publication [...].

Novel Benzenesulfonate Scaffolds with a High Anticancer Activity and G2/M Cell Cycle Arrest.

Sulfonates, unlike their derivatives, sulphonamides, have rarely been investigated for their anticancer activity. Unlike the well-known sulphonamides, esters are mainly used as convenient intermediates in a synthesis. Here, we present the first in-depth investigation of quinazoline sulfonates. A small series of derivatives were synthesized and tested for their anticancer activity. Based on their structural similarity, these compounds resemble tyrosine kinase inhibitors and the p53 reactivator CP-31398. Their biological activity profile, however, was more related to sulphonamides because there was a strong cell cycle arrest in the G2/M phase. Further investigation revealed a multitargeted mechanism of the action that corresponded to the p53 protein status in the cell. Although the compounds expressed a high submicromolar activity against leukemia and colon cancers, pancreatic cancer and glioblastoma were also susceptible. Apoptosis and autophagy were confirmed as the cell death modes that corresponded with the inhibition of metabolic activity and the activation of the p53-dependent and p53-independent pathways. Namely, there was a strong activation of the p62 protein and GADD44. Other proteins such as cdc2 were also expressed at a higher level. Moreover, the classical caspase-dependent pathway in leukemia was observed at a lower concentration, which again confirmed a multitargeted mechanism. It can therefore be concluded that the sulfonates of quinazolines can be regarded as promising scaffolds for developing anticancer agents.

New derivatives of 4'-phenyl-2,2':6',2″-terpyridine as promising anticancer agents.

Terpyridine derivatives are known from their broad application including anticancer properties. In this work we present the newly synthesized 4'-phenyl-2,2':6',2″-terpyridine group with high antiproliferative activity. We suggest that these compounds influence cellular redox homeostasis. Cancer cells are particularly susceptible to any changes in the redox balance because of their handicapped and inefficient antioxidant cellular systems. The antiproliferative activity of the studied compounds was tested on five different cell lines that represent several types of tumours; glioblastoma, leukemia, breast, pancreatic and colon. Additionally, we also tested their selectivity towards normal cells. We performed molecular biology studies in order to detect the response of a cell to its treatment with the compounds that were tested. We looked at the in-depth changes in the proteins and cellular pathways that lead to cell cycle inhibition (G0/G1 and S), and consequently, death on the apoptosis and autophagy pathways. We proved that the studied compounds targeted DNA as well. Special attention was paid to the targets connected with ROS generation.

An Organic-Inorganic Hybrid Nanocomposite as a Potential New Biological Agent.

To solve the problem of human diseases caused by a combination of genetic and environmental factors or by microorganisms, intense research to find completely new materials is required. One of the promising systems in this area is the silver-silica nanocomposites and their derivatives. Hence, silver and silver oxide nanoparticles that were homogeneously distributed within a silica carrier were fabricated. Their average size was d = (7.8 ± 0.3) nm. The organic polymers (carboxymethylcellulose (CMC) and sodium alginate (AS)) were added to improve the biological features of the nanocomposite. The first system was prepared as a silver chlorine salt combination that was immersed on a silica carrier with coagulated particles whose size was d = (44.1 ± 2.3) nm, which coexisted with metallic silver. The second system obtained was synergistically interacted metallic and oxidized silver nanoparticles that were distributed on a structurally defective silica network. Their average size was d = (6.6 ± 0.7) nm. Physicochemical and biological experiments showed that the tiny silver nanoparticles in Ag/SiO2 and Ag/SiO2@AS inhibited E. coli, P. aeruginosa, S. aureus, and L. plantarum's cell growth as well as caused a high anticancer effect. On the other hand, the massive silver nanoparticles of Ag/SiO2@CMC had a weaker antimicrobial effect, although they highly interacted against PANC-1. They also generated reactive oxygen species (ROS) as well as the induction of apoptosis via the p53-independent mechanism.

Cell Wall Composition as a Marker of the Reprogramming of the Cell Fate on the Example of a Daucus carota (L.) Hypocotyl in Which Somatic Embryogenesis Was Induced.

Changes in the composition of the cell walls are postulated to accompany changes in the cell's fate. We check whether there is a relationship between the presence of selected pectic, arabinogalactan proteins (AGPs), and extensins epitopes and changes in cell reprogramming in order to answer the question of whether they can be markers accompanying changes of cell fate. Selected antibodies were used for spatio-temporal immunolocalization of wall components during the induction of somatic embryogenesis. Based on the obtained results, it can be concluded that (1) the LM6 (pectic), LM2 (AGPs) epitopes are positive markers, but the LM5, LM19 (pectic), JIM8, JIM13 (AGPs) epitopes are negative markers of cells reprogramming to the meristematic/pluripotent state; (2) the LM8 (pectic), JIM8, JIM13, LM2 (AGPs) and JIM11 (extensin) epitopes are positive markers, but LM6 (pectic) epitope is negative marker of cells undergoing detachment; (3) JIM4 (AGPs) is a positive marker, but LM5 (pectic), JIM8, JIM13, LM2 (AGPs) are negative markers for pericycle cells on the xylem pole; (4) LM19, LM20 (pectic), JIM13, LM2 (AGPs) are constitutive wall components, but LM6, LM8 (pectic), JIM4, JIM8, JIM16 (AGPs), JIM11, JIM12 and JIM20 (extensins) are not constitutive wall components; (5) the extensins do not contribute to the cell reprogramming.

Anticancer activity of 4'-phenyl-2,2':6',2″-terpyridines - behind the metal complexation.

Terpyridine complexes are known for their broad biological activities, of which their anticancer potency is the most extensively studied. Strikingly, free ligand activity has rarely been described in the literature. In this study, a lipophilic derivative of terpyridine 4'-(1-decyl-2,3-triazol-4-yl)phenyl-2,2':6',2″-terpyridine (L) and its complexes were investigated to determine their mechanism of anticancer activity. Our results show that a free ligand expresses the same level of activity on a panel of cancer cells with a low toxicity towards normal fibroblasts as complexes with Cd, Zn or Cu. Breast cancer (MCF-7 cell line) was the most vulnerable for the tested compounds with the IC50 values in the nanomolar range (IC50 = 40 nM for L.) The addition of Cu(II) ions increased its activity even further, thus suggesting that ligand exchange and ROS production are the main components of its activity. A cell cycle analysis indicated its inhibition at the G0/G1 phase and the subsequent apoptosis as the cell death mode. A detailed analysis of the protein level that was involved in the aforementioned processes confirmed previous results. Furthermore, the reactive oxygen species generation and DNA intercalation confirmed its cleaving activity.

The synthesis and anticancer activity of 2-styrylquinoline derivatives. A p53 independent mechanism of action.

A series of styrylquinolines was designed and synthesized based on the four main quinoline scaffolds including oxine, chloroxine and quinolines substituted with a hydroxyl group or chlorine atom at the C4 position. All of the compounds were tested for their anticancer activity on wild-type colon cancer cells (HCT 116) and those with a p53 deletion. Analysis of SAR revealed the importance of electron-withdrawing substituents in the styryl part and chelating properties in the quinoline ring. The compounds that were more active were also tested on a panel of four cancer cell lines with mutations in TP53 tumor suppressor gene. The results suggest that styrylquinolines induce cell cycle arrest and activate a p53-independent apoptosis. The apparent mechanism of action was studied for the most promising compounds, which produced reactive oxygen species and changed the cellular redox balance.

Synthesis of 8-hydroxyquinoline glycoconjugates and preliminary assay of their ß1,4-GalT inhibitory and anti-cancer properties.

8-Hydroxyquinoline scaffold is a privileged structure used in designing a new active agents with therapeutic potential. Its connections with the sugar unit is formed to improve the pharmacokinetic properties. The broad spectrum of activity of quinoline derivatives, especially glycoconjugates, is often associated with the ability to chelate metal ions or with the ability to intercalate into DNA. Simple and effective methods of synthesis glycoconjugates of 8-hydroxyquinoline and 8-hydroxyquinaldine derivatives, containing an O-glycosidic bond or a 1,2,3-triazole linker in their structure, have been developed. The obtained glycoconjugates were tested for their ability to inhibit ß-1,4-Galactosyltransferase, as well as inhibit cancer cell proliferation. It was found that used glycoconjugation strategy influenced both improvement of activity and improvement of the bioavailability of 8-HQ derivatives. Their activity depends on type of attached sugar, presence of protecting groups in sugar moiety and presence of a linker between sugar and quinolone aglycone.