Pharmaceutical and Safety Profile Evaluation of Novel Selenocompounds with Noteworthy Anticancer Activity

Abstract

Prior studies have reported the potent and selective cytotoxic, pro-apoptotic, and chemopreventive activities of a cyclic selenoanhydride and of a series of selenoesters. Some of these selenium derivatives demonstrated multidrug resistance (MDR)-reversing activity in different resistant cancer cell lines. Thus, the aim of this study was to evaluate the pharmaceutical and safety profiles of these selected selenocompounds using alternative methods in silico and in vitro. One of the main tasks of this work was to determine both the physicochemical properties and metabolic stability of these selenoesters. The obtained results proved that these tested selenocompounds could become potential candidates for novel and safe anticancer drugs with good ADMET parameters. The most favorable selenocompounds turned out to be the phthalic selenoanhydride (EDA-A6), two ketone-containing selenoesters with a 4-chlorophenyl moiety (EDA-71 and EDA-73), and a symmetrical selenodiester with a pyridine ring and two selenium atoms (EDA-119).

Keywords: ADMET; Ames test; PAMPA; anticancer activity; metabolic stability; pharmaceutical profile; selenoesters.

Figure 1

Tested selenocompounds with significant anticancer activity.

Figure 2

ADME and safety experiments carried out in this work for specific selenocompounds.

Scheme 1

Calculation of the in vitro permeability (cm/s). A (filter area) cm² = 0.3; V_D (donor well volume) mL = 0.3; V_A (acceptor well volume) mL = 0.2; t (incubation time) seconds = 18,000; C_A(t) (compound concentration in acceptor well at time t); C_D(t) (compound concentration in donor well at time t).

Figure 3

In silico metabolic stability of EDA-71 selenoester estimated with MetaSite.

Figure 4

Stability of EDA-71 in TRIS buffer (pH = 7.4) and LC–MS/MS ionization conditions. Degradation compounds whose mass ranged from m/z= 97.04 to m/z= 540.39 were observed, and a maternal compound peak (EDA-71, m/z = 276.60) was not found. Potential degradation compounds observed: dehydration product with m/z = 260.12; dimer product with m/z = 540.39; and ion confirming the breakdown of selenoester bond (m/z = 138.97).

Figure 5

Stability of EDA-71 during its analysis in organic solvents. The assay confirmed the presence of only one peak, which corresponded to the weight of EDA-71 (m/z = 276.60). Diode Array, range: 1.327× 10².

Figure 6

(A) The UPLC (ultra-performance liquid chromatography) spectra obtained after the incubation of EDA-71 with human liver microsomes. Like the control sample with TRIS buffer, it presented a dehydration product (m/z = 260.12). Diode Array, range: 1.69 × 10². (B) MS spectra obtained after the incubation of human liver microsomes with the EDA-71 selenoester. Like the control sample with TRIS, it showed a dehydration product (m/z = 260.12). (C) MS spectra obtained after the incubation of human liver microsomes with the EDA-71 selenoester. Like the control sample with TRIS, it showed the EDA-71 dimer (m/z = 540.39).

Figure 6

(A) The UPLC (ultra-performance liquid chromatography) spectra obtained after the incubation of EDA-71 with human liver microsomes. Like the control sample with TRIS buffer, it presented a dehydration product (m/z = 260.12). Diode Array, range: 1.69 × 10². (B) MS spectra obtained after the incubation of human liver microsomes with the EDA-71 selenoester. Like the control sample with TRIS, it showed a dehydration product (m/z = 260.12). (C) MS spectra obtained after the incubation of human liver microsomes with the EDA-71 selenoester. Like the control sample with TRIS, it showed the EDA-71 dimer (m/z = 540.39).

Figure 7

Safety profile (384-well microfluctuation Ames test) for the selenoesters with very high cytostatic activity, DMSO—solvent control. All tested compounds and references were evaluated at 1 and 10 µM concentrations, except for NQNO (0,5 µM); ---- baseline defining the mutagenicity threshold (over this line).

Figure 8

Safety profile (384-well microfluctuation Ames test) for the selenoesters with high cytostatic activity. DMSO—solvent control. All tested compounds and references were evaluated at 1 and 10 µM concentrations, except for NQNO (0,5 µM); ---- baseline defining the mutagenicity threshold (over this line).

Figure 9

Safety profile (384-well microfluctuation Ames test) for the selenoesters with significant cytostatic activity. DMSO—solvent control. All tested compounds and references were evaluated at 1 and 10 µM concentrations, except for NQNO (0,5 µM); ---- baseline defining the mutagenicity threshold (over this line).

Figure 10

Reference experiment results for organic selenocompounds in two concentrations: 1 µM (marked with light grey) and 10 µM (marked with dark grey); NB2—nutrient broth no. 2 without bacteria (background control). NB2 + TA100—control with Salmonella Typhimurium TA100 strain alone; NB2 + TA100 + DMSO—solvent control; MetSeAc—methylseleninic acid (anticancer selenocompound); DOXO—doxorubicin (standard cytostatic compound).