An azaphenothiazine derivative, 6-chloroethylureidoethyldiquino[3,2-b;2’,3’-e][1,4]thiazine (DQT) has recently been shown to exhibit immunosuppressive activities in mouse models. It also inhibited the expression of CXCL10 at the protein level, at non-toxic concentrations, in the culture of KERTr cells treated with double-stranded RNA, poly(I:C). In this report, we demonstrated that DQT inhibits the transcription of the CXCL10 gene. Although CXCL10 is an IFNγ-inducible protein, we found that the CXCL10 protein was induced without the detectable release of IFNγ or IκB degradation. Hence, we concluded that IFNγ or NFκB were not involved in the regulation of the CXCL10 gene in KERTr cells transfected with poly(I:C) as well as in the inhibitory activity of DQT. On the other hand, we found that IFNβ was induced under the same conditions and its expression was inhibited by DQT. Kinetic analysis showed that an increase in IFNβ concentrations occurred 4-8 h after poly(I:C) treatment, while the concentration of CXCL10 was undetectable at that time and started to increase later, when IFNβ reached high levels. Therefore, DQT may be regarded as a new promising inhibitor of IFNβ expression and IFNβ-dependent downstream genes and proteins, e.g., CXCL10 chemokine, which is implicated in pathogenesis of autoimmune diseases.

Phenothiazine derivatives are widely studied in various fields such as biology, chemistry, and medicine research because of their pharmaceutical effects. The first reagent that was used suc-cessfully in the treatment of psychosis was a phenthiazine derivative, chlorpromazine. Apart from their activity in neurons, chlorpromazine have also been reported to display anticancer and antibacterial properties. In these studies, we present the synthesis and research on the activ-ity against A549, MDA, MiaPaCa, PC3 and HCT116 cancer cell lines and against S. aureus, S. epi-dermidis, E. coli and P. aeruginosa bacterial strains a series of new tetracyclic chlorpromazine ana-logues containing a quinoline scafford in their structure instead of the benzene ring and various substituents at the thiazine nitrogen. The structure of these novel molecules has been deter-mined by 1H NMR, 13C NMR and HRMS spectral techniques. The seven most active of the twen-ty-four new chlorpromazine analogues tested were selected for study of the mechanism of cyto-toxic action. Their ability to induce apoptosis or necrosis in cancer cells was assessed by flow cytometry analysis. The results obtained confirmed the proapoptotic activity of selected com-pounds, especially in terms of inducing late apoptosis or necrosis in cancer cell lines A549, Mi-aPaCa-2 and HCT-116. Furthermore, studies on the induction of cell cycle arrest suggest that the new chlorpromazine analogues exert antiproliferative effects by inducing cell cycle arrest in the S phase and, consequently, apoptosis.