Background: Protein disulphide isomerases (PDIs) play an important role in cancer progression. However, the relative contribution of the various isoforms of PDI in tumorigenesis is not clear. Methods: The content of PDI isoforms in 22 cancer cells lines was investigated using LC–MS/MS-based proteomic analysis. The effects of PDIA1, PDIA3 and PDIA17 inhibition on the proliferation, migration and adhesion of MCF-7 and MDA-MB-231 cells, identified as high and low PDIA17 expressing cells, respectively, were assessed using novel aromatic N-sulphonamides of aziridine-2-carboxylic acid derivatives as PDI inhibitors. Results: PDIA1 and PDIA3 were the most abundant in cancer cell lysates and were also detected extracellularly in breast cancer cells (MDA-MB-231 and MCF-7). Some cancer cell lines (e.g., MCF-7, HT-29) showed upregulated expression of PDIA17, whereas in others (e.g., MDA-MB-231, 67NR), PDIA17 was not detected. The simultaneous inhibition of PDIA1 and PDIA3 showed similar anti-proliferative effects in MCF-7 and MDA-MB-231 breast cancer cells. However, the inhibition of PDIA1 and PDIA17 in the MCF-7 cell line resulted in more effective anti-adhesive and anti-proliferative effects. Conclusions: PDIA1 and PDIA3 represent major isoforms of multiple cancer cells, and their non-selective inhibition displays significant anti-proliferative effects irrespective of whether or not PDIA17 is present. The more pronounced anti-adhesive effects of PDI inhibition in hormone-sensitive MCF-7 cells featured by higher levels of PDIs when compared to triple-negative MDA-MB-231 cells suggests that targeting extracellular PDIA1 and PDIA3 with or without additional PDIA17 inhibition may represent a strategy for personalized anti-adhesive, anti-metastatic therapy in cancers with high PDI expression.

Numerous studies have proven that both stimulation and blockade of 5-HT_1A and the blockade of 5-HT₇ receptors might cause the anxiolytic-like effects. Biased agonists selectively activate specific signaling pathways. Therefore, they might offer novel treatment strategies. In this study, we investigated the anxiolytic-like activity, as well as the possible mechanism of action of 1-[(2,5-dimethylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-17). In our previous experiments, HBK-17 showed high affinity for 5-HT_1A and 5-HT₇ receptors and antidepressant-like properties. We performed the four plate test and the elevated plus maze test to determine anxiolytic-like activity. Toward a better understanding of the pharmacological properties of HBK-17 we used various functional assays to determine its intrinsic activity at 5-HT_1A, 5-HT_2A, 5-HT₇, and D₂ receptors and UHPLC-MS/MS method to evaluate its pharmacokinetic profile. We observed the anxiolytic-like activity of HBK-17 in both behavioral tests and the effect was reversed by the pretreatment with WAY-100635, which proves that 5-HT_1A receptor activation was essential for the anxiolytic-like effect. Moreover, the compound moderately antagonized D₂, weakly 5-HT₇ and very weakly 5-HT_2A receptors. We demonstrated that HBK-17 preferentially activated ß-arrestin signaling after binding to the 5-HT_1A receptor. HBK-17 was rapidly absorbed after intraperitoneal administration and had a half-life of about 150 min. HBK-17 slightly penetrated the peripheral compartment and showed bioavailability of approximately 45%. The unique pharmacological profile of HBK-17 encourages further experiments to understand its mechanism of action fully.

The effect of some antidepressants co-administered with EMD386088 in the modified forced swim test in rats was investigated. Additionally, the pharmacokinetics, metabolic stability, and the effect of EMD386088 on P450 cytochromes were determined. Intraperitoneal (i.p.) coadministration of EMD386088 (2.5 mg/kg) and imipramine (15 mg/kg), reboxetine (5 mg/kg), moclobemide (10 mg/kg), or bupropion (10 mg/kg) evoked significant antidepressant-like activity, whereas no effect was observed after joint administration of EMD386088 with s-citalopram (10 mg/kg). Pharmacokinetic in vivo investigation showed a rapid absorption of EMD386088 (2.5 and 5 mg/kg) with t _1/2 = 67 min (t _max = 5 min). Large volume of distribution (V _d/F = 102 L/kg) indicated its penetration into peripheral compartments. The most active coadministration of EMD386088 (2.5 mg/kg) with imipramine (15 mg/kg) resulted in slower absorption of the compound (C _max = 60 min) and decrease in the volume of distribution (V _d/F = 32.2 L/kg). EMD386088 penetrates the blood–brain barrier with a high brain/plasma ratio of about 19 (2.5 mg/kg) and 7.5 for coadministration with imipramine. The in silico and in vitro studies on EMD386088 metabolic stability showed the dehydrogenation of tetrahydropyridine moiety as its main metabolic pathway. EMD386088 did not influence on CYP3A4 activity, and it has been classified as a very weak CYP2D6 inhibitor (IC ₅₀ = 2.25 μM). The results obtained from the forced swim test in rats indicate that an activation of 5HT₆ receptor may facilitate antidepressant-like activity of some antidepressants. The pharmacokinetic results suggest that the interaction between EMD386088 and imipramine could not have been pharmacokinetic in nature.