Novel triazolophthalazine-hydrazone hybrids as potential PCAF inhibitors: Design, synthesis, in vitro anticancer evaluation, apoptosis, and molecular docking studies.

Three novel series of triazolophthalazine derivatives bearing hydrazone moiety were designed, synthesized, and evaluated for their anticancer activity against four human cancer cell lines by MTT assay. Six derivatives demonstrated comparable activity with Doxorubicin reference drug against the selected cancer cells. Especially, compound 16 showed the most potent activity with IC50 values of 5.70, 8.04, 11.15, and 4.25, µM against HePG2, MCF-7, PC3, and HCT-116 respectively. Also, compound 26 exhibited comparable inhibitory effect with that of Doxorubicin against the selected cancer cell lines with IC50 values of 6.45, 8.63, 12.28, and 7.03 µM against HePG2, MCF-7, PC3, and HCT-116 respectively. Investigation of the apoptotic activity of the two most active compounds revealed that compounds 16 and 26 could induce both the early and the late apoptosis of HePG2. Further mechanistic study of the HePG2 cell cycle confirmed the spectacular cytotoxic and apoptotic effects of both compounds. Compounds 16 and 26 showed a pronounced increase in cells in G2/M and Pre G1 phases with a concomitant reduction of cells in G0-G1 and S phases. A follow up enzymatic assay indicated that these two compounds have comparable activities with that of bromosporine as PCAF inhibitors with IC50 values of 8.13 and 5.31 µM respectively. Moreover, molecular docking study for all the synthesized compounds was performed to predict their binding affinities toward the active site of histone acetyltransferase GCN5. Results of molecular docking were strongly correlated with that of the cytotoxicity study.

Effect of N-Acetyltransferase 2 Genotype on the Pharmacokinetics of Hydralazine During Pregnancy.

Hydralazine, an antihypertensive agent used during pregnancy, undergoes N-acetylation primarily via N-acetyltransferase 2 (NAT2) to form 3-methyl-1,2,4-triazolo[3,4-a]phthalazine (MTP). To characterize the steady-state pharmacokinetics (PK) of hydralazine during pregnancy and evaluate the effects of NAT2 genotype on hydralazine and MTP PK during pregnancy, 12 pregnant subjects received oral hydralazine (5-25 mg every 6 hours) in mid- (n = 5) and/or late pregnancy (n = 8). Serial blood samples were collected over 1 dosing interval, and steady-state noncompartmental PK parameters were estimated. Subjects were classified as either (rapid acetylators, n = 6) or slow acetylators (SAs, n = 6) based on NAT2 genotype. During pregnancy, when compared with the SA group, the RA group had faster weight-adjusted hydralazine apparent oral clearance (70.0 ± 13.6 vs 20.1 ± 6.9 L/h, P < .05), lower dose-normalized area under the concentration-time curve (AUC; 1.5 ± 0.8 vs 5.9 ± 3.7 ng·h/mL, P < .05), lower dose-normalized peak concentrations (0.77 ± 0.51 vs 4.04 ± 3.18 ng/mL, P < .05), and larger weight-adjusted apparent oral volume of distribution (302 ± 112 vs 116 ± 45 L/kg, P < .05). Furthermore, the MTP/hydralazine AUC ratio was ∼10-fold higher in the RA group (78 ± 30 vs 8 ± 3, P < .05) than in the SA group. No gestational age or dose-dependent effects were observed, possibly because of the small sample size. This study describes for the first time, the PK of oral hydralazine and its metabolite, MTP, during pregnancy, and confirmed that the PK of oral hydralazine is NAT2 genotype dependent during pregnancy.

Design, Synthesis, In Vitro Anti-cancer Activity, ADMET Profile and Molecular Docking of Novel Triazolo[3,4-a]phthalazine Derivatives Targeting VEGFR-2 Enzyme.

BACKGROUND: Extensive studies were reported in the synthesis of several phthalazine derivatives as promising anticancer agents as potent VEGFR-2 inhibitors. Vatalanib (PTK787) was the first anilinophthalazine published derivative as a potent inhibitor of VEGFR. The discovery of vatalanib as a clinical candidate led to the design and synthesis of different anilinophthalazine derivatives as potent inhibitors for VEGFR-2. The objective of present research work is the synthesis of new agents with the same essential pharmacophoric features of the reported and clinically used VEGFR-2 inhibitors (e.g vatalanib and sorafenib). The main core of our molecular design rationale comprised bioisosteric modification strategies of VEGFR-2 inhibitors at four different positions. MATERIAL AND METHODS: A correlation between structure and biological activity of our designed phthalazines was established using molecular docking and VEGFR-2 kinase assay. RESULTS AND DISCUSSION: In view of their expected anticancer activity, novel triazolo[3,4-a]phthalazine derivatives 5-6a-o and 3-substituted-bis([1,2,4]triazolo)[3,4-a:4',3'-c]phthalazines 9a-b were designed, synthesized and evaluated for their anti-proliferative activity against two human tumor cell lines HCT-116 human colon adenocarcinoma and MCF-7 breast cancer. It was found that, compound 6o the most potent derivative against both HCT116 and MCF-7 cancer cell lines. Compounds 6o, 6m, 6d and 9b showed the highest anticancer activities against HCT116 human colon adenocarcinoma with IC50 of 7±0.06, 13±0.11, 15±0.14 and 23±0.22 µM respectively while compounds 6o, 6d, 6a and 6n showed the highest anticancer activities against MCF-7 breast cancer with IC50 of 16.98±0.15, 18.2±0.17, 57.54±0.53 and 66.45±0.67 µM respectively. Sorafenib as a highly potent VEGFR-2 inhibitor was used as a reference drug with IC50 of 5.47±0.3 and 7.26±0.3 µM respectively. Nine compounds were further evaluated for their VEGFR-2 inhibitory activity. Compounds 6o, 6m, 6d and 9b emerged as the most active counterparts against VEGFR-2 with IC50 values of 0.1±0.01, 0.15±0.02, 0.28±0.03 and 0.38±0.04 µM, respectively comparable to that of sorafenib (IC50 = 0.1±0.02) µM. Furthermore, molecular docking studies were carried out for all synthesized compounds to investigate their binding pattern and predict their binding affinities towards VEGFR-2 active site. In silico ADMET studies were calculated for the tested compounds. Most of our designed compounds exhibited good ADMET profile. CONCLUSION: The obtained results showed that, the most active compounds could be useful as a template for future design, optimization, adaptation and investigation to produce more potent and selective VEGFR-2 inhibitors with higher anticancer analogs.

Design, Synthesis, Molecular Docking, and Anticancer Activity of Phthalazine Derivatives as VEGFR-2 Inhibitors.

Novel series of phthalazine derivatives 6-11 were designed, synthesized, and evaluated for their anticancer activity against two human tumor cell lines, HCT-116 human colon adenocarcinoma and MCF-7 breast cancer cells, targeting the VEGFR-2 enzyme. Compounds 7a,b and 8b,c showed the highest anticancer activities against both HCT116 human colon adenocarcinoma cells with IC50 of 6.04 ± 0.30, 13.22 ± 0.22, 18 ± 0.20, and 35 ± 0.45 µM, respectively, and MCF-7 breast cancer cells with IC50 of 8.8 ± 0.45, 17.9 ± 0.50, 25.2 ± 0.55, and 44.3 ± 0.49 µM, respectively, in comparison to sorafenib as reference drug with IC50 of 5.47 ± 0.3 and 7.26 ± 0.3 µM, respectively. Eleven compounds in this series were further evaluated for their inhibitory activity against VEGFR-2, where compounds 7a, 7b, 8c, and 8b also showed the highest VEGFR-2 inhibition with IC50 of 0.11 ± 0.01, 0.31 ± 0.03, 0.72 ± 0.08, and 0.91 ± 0.08 µM, respectively, in comparison to sorafenib as reference ligand with IC50 of 0.1 ± 0.02. Furthermore, molecular docking studies were performed for all synthesized compounds to predict their binding pattern and affinity towards the VEGFR-2 active site, in order to rationalize their anticancer activity in a qualitative way.

Synthesis and positive inotropic evaluation of [1,2,4]triazolo[3,4-a]phthalazine and tetrazolo[5,1-a]phthalazine derivatives bearing substituted piperazine moieties.

Four series of [1,2,4]triazolo[3,4-a]phthalazine and tetrazolo[5,1-a]phthalazine derivatives bearing substituted piperazine moieties were synthesized and evaluated for their positive inotropic activity by measuring the left atrium stroke volume in isolated rabbit-heart preparations. Several compounds were developed and showed favorable activities compared to the standard drug milrinone, with (4-([1,2,4]triazolo[3,4-a]phthalazin-6-yl)piperazin-1-yl)(p-tolyl)methanone (5g) being identified as the most potent with an increased stroke volume of 19.15±0.22% (milrinone: 2.46±0.07%) at a concentration of 3×10(-5) M. A preliminary study of mechanism of action revealed that 5g displayed its positive inotropic effect may be related to the PDE-cAMP-PKA signaling pathway. Compounds exhibiting inotropic effects were also evaluated in terms of the chronotropic effects.