Synthesis of 1,2,4-Triazinones Exploiting the Reactivity of Diazadiene and N-Isocyanate Intermediates.

1,2,4-Triazinones are useful compounds, but their synthesis can be challenging. Herein, we report a strategy to build 1,2,4-triazinones using α-bromohydrazones to access diazadienes and exploiting their ability to undergo facile substitution with nitrogen nucleophiles. The N-isocyanate intermediate formed in situ can then undergo cyclization to give the desired triazinones. This provides access to products with various substituents at the 4-position, and with suitable hydrazone precursors (R2 = Ph), the cascade reaction yields 1,2,4-triazin-3(2H)-ones at room temperature.

New 1,3,4-oxadiazole-chalcone/benzimidazole hybrids as potent antiproliferative agents.

A series of new 1,3,4-oxadiazole-chalcone/benzimidazole hybrids 9a-o and 10a-k were designed and synthesized as potential antiproliferative agents. Hybrids 9a-o exhibited remarkable antiproliferative activities on different NCI-60 cell lines in a single-dose assay. The antiproliferative activities of the newly synthesized compounds were evaluated against a panel of four human cancer cell lines (A-549, MCF-7, Panc-1, and HT-29). Compounds 9g-i and their oxygen isosteres, 10f-h, exhibited promising antiproliferative activities with IC50 values ranging from 0.80 to 2.27 µM compared to doxorubicin (IC50 ranging from 0.90 to 1.41 µM). Furthermore, the inhibitory potency of these compounds against the epidermal growth factor receptor (EGFR) and BRAFV600E kinases was evaluated using erlotinib as a reference drug. Molecular modeling studies were done to investigate the binding mode of the most active hybrids in the ATP binding site of EGFR.

Design, synthesis, in vitro antiproliferative evaluation and in silico studies of new VEGFR-2 inhibitors based on 4-piperazinylquinolin-2(1H)-one scaffold.

Angiogenesis is essential in the growth of solid tumors which need oxygen and nutrients supply to grow in size. The VEGF/VEGFR-2 signaling pathway plays an important role in tumor angiogenesis. Sorafenib is an FDA approved cancer therapeutic with activity against many protein kinases, including VEGFR. We designed 4-piperazinylquinolin-2(1H)-ones with variable aromatic moieties and Mannich bases as Sorafenib analogues as potential inhibitors of angiogenesis. In this study, we investigated the impact of replacing the linker aromatic ring with cyclic tertiary amines and the effect of incorporation of variably substituted distal rings. We hypothesized that cyclic tertiary amines would improve pharmacokinetic properties and contribute to enzyme interactions. Two series of piperazinylquinolinone-based compounds were synthesized, characterized, and evaluated for bioactivity against adenocarcinoma EKVX NSCLC and T-47D breast cancer cells. Ability to inhibit VEGFR-2 and apoptosis were investigated and molecular docking into the enzyme active site and theoretical ADME properties were determined. Notably, amongst series I three compounds exhibited higher anticancer activity than Staurosporine against EKVX NSCLC adenocarcinoma cell line. In series II, nine compounds exhibited higher antiproliferative activity than Staurosporine against T-47D breast cancer cell line. Two compounds; 5d and 7z exhibited lower toxicity against normal cell line (MCF 10A) than Staurosporine. Compound 7z was the most potent agent with IC50 38.76 nM. Moreover, 7z showed VEGFR-2 inhibitory activity higher than sorafenib and induced remarkable levels of both early and late apoptosis (2.82% and 21.30%, respectively). Hence, 5d and 7z are considered promising VEGFR-2 inhibitors with high efficacy against adenocarcinoma EKVX and T-47D breast cancer cells. The target compounds also possessed favorable physicochemical properties and pharmacokinetic parameters These studies further suggested that the 4-piperazinylquinolin-2(1H)-one derivatives developed in this study play a critical role in modulating VEGFR, and guide the design of innovative anticancer therapies.

Discovery of antiproliferative and anti-FAK inhibitory activity of 1,2,4-triazole derivatives containing acetamido carboxylic acid skeleton.

Small molecule inhibitors of the focal adhesion kinase are regarded as promising tools in our armamentarium for treating cancer. Here, we identified four 1,2,4-triazole derivatives that inhibit FAK kinase significantly and evaluated their therapeutic potential. Most tested compounds revealed potent antiproliferative activity in HepG2 and Hep3B liver cancer cells, in which 3c and 3d were the most potent (IC50 range; 2.88 ~ 4.83 µM). Compound 3d possessed significant FAK inhibitory activity with IC50 value of 18.10 nM better than the reference GSK-2256098 (IC50 = 22.14 nM). The preliminary mechanism investigation by Western blot analysis showed that both 3c and 3d repressed FAK phosphorylation comparable to GSK-2256098 in HepG2 cells. As a result of FAK inhibition, 3c and 3d inhibited the pro-survival pathways by decreasing the phosphorylation levels of PI3K, Akt, JNK, and STAT3 proteins. This effect led to apoptosis induction and cell cycle arrest. Taken together, these results indicate that 3d could serve as a potent preclinical candidate for the treatment of cancers.

Novel 4-(piperazin-1-yl)quinolin-2(1H)-one bearing thiazoles with antiproliferative activity through VEGFR-2-TK inhibition.

A new series of 2-(4-(2-oxo-1,2-dihydroquinolin-4-yl)piperazin-1-yl)-N-(4-phenylthiazol-2-yl)acetamide derivatives were synthesized and evaluated for anticancer activity. All target compounds showed anticancer activity higher than that of their 2-oxo-4-piperazinyl-1,2-dihydroquinolin-2(1H)-one precursors. Multidose testing of target compounds was performed against breast cancer T-47D cell line. Five compounds showed higher cytotoxic activity than Staurosporine. The dihalogenated derivative showed the best cytotoxic activity with IC50 2.73 ± 0.16 µM. In addition, the VEGFR-2 inhibitory activity of all synthetic compounds was evaluated. Two compounds of 6-fluoro-4-(piperazin-1-yl)quinolin-2(1H)-ones showed inhibitory activity comparable to sorafenib with IC50 46.83 ± 2.4, 51.09 ± 2.6 and 51.41 ± 2.3 nM, respectively. The cell cycle analysis of two compounds namely, 2-(4-(6-fluoro-2-oxo-1,2-dihydroquinolin-4-yl)piperazin-1-yl)-N-(4-phenylthiazol-2-yl)acetamide and N-(4-(4-chlorophenyl)thiazol-2-yl)-2-(4-(2-oxo-1-phenyl-1,2-dihydroquinolin-4-yl)piperazin-1-yl)acetamide revealed that the arrest of cell cycle occurred at S phase. In apoptosis assay, the same two compounds were able to induce significant levels of early and late apoptosis. In a similar manner to Sorafenib, docking of target compounds with VEGFR-2 protein 4ASD showed HB with Cys919 in hinge region of enzyme and HB with both Glu885 and Asp1046 in gate area. Using SwissADME, all target compounds were predicted to be highly absorbed from gastrointestinal tract with no BBB permeability. It is clear that the two compounds are promising antiproliferative candidates that require further optimization.

Design and synthesis of novel quinoline/chalcone/1,2,4-triazole hybrids as potent antiproliferative agent targeting EGFR and BRAFV600E kinases.

New quinoline / chalcone hybrids containing 1,2,4-triazole moiety have been designed, synthesized and their structures elucidated and confirmed by various spectroscopic techniques. The designed compounds showed moderate to good activity on different NCI 60 cell lines in a single-dose assay with a growth inhibition rate ranging from 50% to 94%. Compounds 7b, 7d, 9b, and 9d were the most active compounds in most cancer cell lines with a growth inhibition percent between 77% and 94%. Newly synthesized hybrids were evaluated for their anti-proliferative activity against a panel of four human cancer cell lines. Compounds 7a, 7b, 9a, 9b, and 9d showed promising antiproliferative activities. These compounds were further tested for their inhibitory potency against EGFR and BRAFV600E kinases with erlotinib as a reference drug. The molecular docking study of compounds 7a, 7b, 9a, 9b, and 9d revealed nice fitting into the active site of EGFR and BRAFV600E kinases. Compounds 7b, 9b, and 9d displayed the highest binding affinities and similar binding pattern to those of erlotinib.

Tubulin inhibitors: Discovery of a new scaffold targeting extra-binding residues within the colchicine site through anchoring substituents properly adapted to their pocket by a semi-flexible linker.

Bis-hydrazides 13a-h were designed and synthesized as potential tubulin inhibitors selectively targeting the colchicine site between α- and ß-tubulin subunits. The newly designed ring-B substituents were assisted at their ends by 'anchor groups' which are expected to exert binding interaction(s) with new additional amino acid residues in the colchicine site (beyond those amino acids previously reported to interact with reference inhibitors as CA-4 and colchicine). Conformational flexibility of bis-hydrazide linker assisted these 'extra-binding' properties through reliving ligands' strains in the final ligand-receptor complexes. Compound 13f displayed the most promising computational and biological study results in the series: MM/GBSA binding energy of -62.362 kcal/mol (extra-binding to Arg α:221, Thr ß:353 & Lys ß:254); 34% NCI-H522 cells' death (at 10 µM), IC50 = 0.073 µM (MTT assay); significant cell cycle arrest at G2/M phase; 11.6% preG1 apoptosis induction and 83.1% in vitro tubulin inhibition (at concentration = IC50). Future researchers in bis-hydrazide tubulin inhibitors are advised to consider the 2-chloro-N-(4-substituted-phenyl)acetamide derivatives as compound 13f due to extra-binding properties of their ring B.

1,3,4-oxadiazole/chalcone hybrids: Design, synthesis, and inhibition of leukemia cell growth and EGFR, Src, IL-6 and STAT3 activities.

A new series of 1,3,4-oxadiazole/chalcone hybrids was designed, synthesized, identified with different spectroscopic techniques and biologically evaluated as inhibitors of EGFR, Src, and IL-6. The synthesized compounds showed promising anticancer activity, particularly against leukemia, with 8v being the most potent. The synthesized compounds exhibited strong to moderate cytotoxic activities against K-562, KG-1a, and Jurkat leukemia cell lines in MTT assays. Compound 8v showed the strongest cytotoxic activity with IC50 of 1.95 µM, 2.36 µM and 3.45 µM against K-562, Jurkat and KG-1a leukemia cell lines, respectively. Moreover; the synthesized compounds inhibited EGFR, Src, and IL-6. Compound 8v was most effective at inhibiting EGFR (IC50 = 0.24 µM), Src (IC50 = 0.96 µM), and IL-6 (% of control = 20%). Additionally, most of the compounds decreased STAT3 activation.

Novel quinoline incorporating 1,2,4-triazole/oxime hybrids: Synthesis, molecular docking, anti-inflammatory, COX inhibition, ulceroginicity and histopathological investigations.

A series of novel quinolines incorporating 1,2,4-triazole/oxime hybrids were prepared. They showed remarkable anti-inflammatory activity and exhibited very low incidence of gastric ulceration, compared to indomethacin. Most of the compounds tested showed remarkable inhibition of the COX-1 isozyme, with IC50's ranging from 0.48 to 28µM. Compounds 7c and 9g showed high safety profiles with normal stomach tissue integrity. Docking studies supported the observed in vitro inhibitory activity towards the COX enzymes that may explain their promising anti-inflammatory activity relative to indomethacin. Moreover, differences between the COX-1 and COX-2 isozymes in observed energy scores, as well as in the number of interactions with some of the compounds tested, might predict their higher selectivity towards COX-1 rather than COX-2. Compound 9e was found to inhibit both COXs non-competitively with Ki values of 81µM and 94.6µM.

Sugar-based amphiphilic polymers for biomedical applications: from nanocarriers to therapeutics.

Various therapeutics exhibit unfavorable physicochemical properties or stability issues that reduce their in vivo efficacy. Therefore, carriers able to overcome such challenges and deliver therapeutics to specific in vivo target sites are critically needed. For instance, anticancer drugs are hydrophobic and require carriers to solubilize them in aqueous environments, and gene-based therapies (e.g., siRNA or pDNA) require carriers to protect the anionic genes from enzymatic degradation during systemic circulation. Polymeric micelles, which are self-assemblies of amphiphilic polymers (APs), constitute one delivery vehicle class that has been investigated for many biomedical applications. Having a hydrophobic core and a hydrophilic shell, polymeric micelles have been used as drug carriers. While traditional APs are typically comprised of nondegradable block copolymers, sugar-based amphiphilic polymers (SBAPs) synthesized by us are comprised of branched, sugar-based hydrophobic segments and a hydrophilic poly(ethylene glycol) chain. Similar to many amphiphilic polymers, SBAPs self-assemble into polymeric micelles. These nanoscale micelles have extremely low critical micelle concentrations offering stability against dilution, which occurs with systemic administration. In this Account, we illustrate applications of SBAPs for anticancer drug delivery via physical encapsulation within SBAP micelles and chemical conjugation to form SBAP prodrugs capable of micellization. Additionally, we show that SBAPs are excellent at stabilizing liposomal delivery systems. These SBAP-lipid complexes were developed to deliver hydrophobic anticancer therapeutics, achieving preferential uptake in cancer cells over normal cells. Furthermore, these complexes can be designed to electrostatically complex with gene therapies capable of transfection. Aside from serving as a nanocarrier, SBAPs have also demonstrated unique bioactivity in managing atherosclerosis, a major cause of cardiovascular disease. The atherosclerotic cascade is usually triggered by the unregulated uptake of oxidized low-density lipoprotein, a cholesterol carrier, in macrophages of the blood vessel wall; SBAPs can significantly inhibit oxidized low-density lipoprotein uptake in macrophages and abrogate the atherosclerotic cascade. By modification of various functionalities (e.g., branching, stereochemistry, hydrophobicity, and charge) in the SBAP chemical structure, SBAP bioactivity was optimized, and influential structural components were identified. Despite the potential of SBAPs as atherosclerotic therapies, blood stability of the SBAP micelles was not ideal for in vivo applications, and means to stabilize them were pursued. Using kinetic entrapment via flash nanoprecipitation, SBAPs were formulated into nanoparticles with a hydrophobic solute core and SBAP shell. SBAP nanoparticles exhibited excellent physiological stability and enhanced bioactivity compared with SBAP micelles. Further, this method enables encapsulation of additional hydrophobic drugs (e.g., vitamin E) to yield a stable formulation that releases two bioactives. Both as nanoscale carriers and as polymer therapeutics, SBAPs are promising biomaterials for medical applications.

Chalcone/1,3,4-Oxadiazole/Benzimidazole hybrids as novel anti-proliferative agents inducing apoptosis and inhibiting EGFR & BRAFV600E.

INTRODUCTION: One of the most robust global challenges and difficulties in the 21st century is cancer. Treating cancer is a goal which continues to motivate researchers to innovate in design and development of new treatments to help battle the disease. OBJECTIVES: Our objective was developing new antiapoptotic hybrids based on biologically active heterocyclic motifs "benzimidazole?oxadiazole-chalcone hybrids'' that had shown promising ability to inhibit EGFR and induce apoptosis. We expected these scaffolds to display anticancer activity via inhibition of BRAF, EGFR, and Bcl-2 and induction of apoptosis through activation of caspases. METHODS: The new hybrids 7a-x were evaluated for their anti-proliferative, EGFR & BRAFV600E inhibitory, and apoptosis induction activities were detected. Docking study & dynamic stimulation into EGFR and BRAFV600E were studied. RESULTS: All hybrids exhibited remarkable cell growth inhibition on the four tested cell lines with IC50 ranging from 0.95 µM to 12.50 µM. which was comparable to Doxorubicin. Compounds 7k-m had the most potent EGFR inhibitory activity. While, compounds 7e, 7g, 7k and 7l showed good inhibitory activities against BRAFV600E. Furthermore, Compounds 7k, 7l, and 7m increased Caspases 3,8 & 9, Cytochrome C and Bax levels and decreased Bcl-2 protein levels. Compounds 7k-m received the best binding scores and showed binding modes that were almost identical to each other and comparable with that of the co-crystalized Erlotinib in EGFR and BRAF active sites. CONCLUSION: Compounds 7k-m could be used as potential apoptotic anti-proliferative agents upon further optimization.

Recent progress in biologically active indole hybrids: a mini review.

The indole moiety is one of the most widespread heterocycles found in both natural products and biological systems. Indoles have important biological activities including anticancer, antioxidant, anti-inflammatory, antifungal, anticholinesterase, and antibacterial properties. Scientists are therefore interested in the synthesis of biologically active indole-based hybrids such as indole-coumarin, indole-chalcone, indole-isatin, indole-pyrimidine and so on, with the aim of improving activity, selectivity, and mitigating side effects. This review will discuss the newly synthesized indole-based hybrids along with their biological activity which will be useful in drug discovery and development.

Antibiotics use and its association with Multi-Drug Resistance in a Tertiary Care Geriatrics Hospital in Egypt.

INTRODUCTION: Multi-Drug Resistance (MDR) is common in hospitalized geriatric patients. The study aims to investigate the pattern of antibiotic use and determine its association with MDR in hospitalized geriatric patients. METHODOLOGY: A retrospective cohort study including 193 geriatric patients admitted to a Geriatric Intensive Care Unit (GICU) in a tertiary care Geriatrics hospital in Egypt, throughout a consecutive 6 months duration. A review of medical records was done to extract clinical, socio-demographic, and prescribing data on antibiotics throughout admission. The presence of MDR organisms (MDROs) was determined by reviewing culture and sensitivity reports. Descriptive statistics and logistic regression analysis were performed. RESULTS: 181 (93.8%) patients received at least 1 antibiotic. Cephalosporins were the most commonly consumed antibiotics (24%). MDROs were significantly associated with receiving ≥ 3 antibiotics. Longer hospital stay was a predictor of multiple antibiotics use (Odds Ratio of 1.075). MDROs were prevalent in 110 (57.0 %) patients. Klebsiella species were the most frequent MDROs (26%) with the highest susceptibility to amikacin. CONCLUSIONS: The study provides a detailed description of both antibiotics use and MDR among hospitalized geriatric patients in Egypt. It gives a novel insight into the ongoing drug-pathogen combinations in acute healthcare settings of the aged. This data has a potential role in applying antimicrobial stewardship programs for hospitalized geriatric patients to mitigate antimicrobial resistance in similar settings.

A first-in-class anticancer dual HDAC2/FAK inhibitors bearing hydroxamates/benzamides capped by pyridinyl-1,2,4-triazoles.

Novel 5-pyridinyl-1,2,4-triazoles were designed as dual inhibitors of histone deacetylase 2 (HDAC2) and focal adhesion kinase (FAK). Compounds 5d, 6a, 7c, and 11c were determined as potential inhibitors of both HDAC2 (IC50 = 0.09-1.40 µM) and FAK (IC50 = 12.59-36.11 nM); 6a revealed the highest activity with IC50 values of 0.09 µM and 12.59 nM for HDAC2 and FAK, respectively. Compound 6a was superior to reference drugs vorinostat and valproic acid in its ability to inhibit growth/proliferation of A-498 and Caki-1 renal cancer cells. Further investigation proved that 6a strongly arrests the cell cycle at the G2/M phase and triggers apoptosis in both A-498 and Caki-1 cells. Moreover, the enhanced Akt activity that is observed upon chronic application of HDAC inhibitors was effectively suppressed by the dual HDAC2/FAK inhibitor. Finally, the high potency and selectivity of 6a towards HDAC2 and FAK proteins were rationalized by molecular docking. Taken together, these findings highlight the potential of 6a as a promising dual-acting HDAC2/FAK inhibitor that could benefit from further optimization.

FAK inhibitors as promising anticancer targets: present and future directions.

FAK, a nonreceptor tyrosine kinase, has been recognized as a novel target class for the development of targeted anticancer agents. Overexpression of FAK is a common occurrence in several solid tumors, in which the kinase has been implicated in promoting metastases. Consequently, designing and developing potent FAK inhibitors is becoming an attractive goal, and FAK inhibitors are being recognized as a promising tool in our armamentarium for treating diverse cancers. This review comprehensively summarizes the different classes of synthetically derived compounds that have been reported as potent FAK inhibitors in the last three decades. Finally, the future of FAK-targeting smart drugs that are designed to slow down the emergence of drug resistance is discussed.

The small molecule curcumin analog FLLL32 induces apoptosis in melanoma cells via STAT3 inhibition and retains the cellular response to cytokines with anti-tumor activity.

BACKGROUND: We characterized the biologic effects of a novel small molecule STAT3 pathway inhibitor that is derived from the natural product curcumin. We hypothesized this lead compound would specifically inhibit the STAT3 signaling pathway to induce apoptosis in melanoma cells. RESULTS: FLLL32 specifically reduced STAT3 phosphorylation at Tyr705 (pSTAT3) and induced apoptosis at micromolar amounts in human melanoma cell lines and primary melanoma cultures as determined by annexin V/propidium iodide staining and immunoblot analysis. FLLL32 treatment reduced expression of STAT3-target genes, induced caspase-dependent apoptosis, and reduced mitochondrial membrane potential. FLLL32 displayed specificity for STAT3 over other homologous STAT proteins. In contrast to other STAT3 pathway inhibitors (WP1066, JSI-124, Stattic), FLLL32 did not abrogate IFN-gamma-induced pSTAT1 or downstream STAT1-mediated gene expression as determined by Real Time PCR. In addition, FLLL32 did not adversely affect the function or viability of immune cells from normal donors. In peripheral blood mononuclear cells (PBMCs), FLLL32 inhibited IL-6-induced pSTAT3 but did not reduce signaling in response to immunostimulatory cytokines (IFN-gamma, IL 2). Treatment of PBMCs or natural killer (NK) cells with FLLL32 also did not decrease viability or granzyme b and IFN-gamma production when cultured with K562 targets as compared to vehicle (DMSO). CONCLUSIONS: These data suggest that FLLL32 represents a lead compound that could serve as a platform for further optimization to develop improved STAT3 specific inhibitors for melanoma therapy.

STAT3 transcription factor as target for anti-cancer therapy.

STATs constitute a large family of transcription activators and transducers of signals that have an important role in many cell functions as regulation of proliferation and differentiation of the cell also regulation of apoptosis and angiogenesis. STAT3 as a member of that family, recently was discovered to have a vital role in progression of different types of cancers. The activation of STAT3 was observed to regulate multiple gene functions during cancer-like cell proliferation, differentiation, apoptosis, metastasis, inflammation, immunity, cell survival, and angiogenesis. The inhibition of STAT3 activation has been an important target for cancer therapy. Inhibitors of STAT3 have been used for a long time for treatment of many types of cancers like leukemia, melanoma, colon, and renal cancer. In this review article, we summarize and discuss different drugs inhibiting the action of STAT3 and used in treatment of different types of cancer.

NO-releasing STAT3 inhibitors suppress BRAF-mutant melanoma growth.

Constitutive activation of STAT3 can play a vital role in the development of melanoma. STAT3-targeted therapeutics are reported to show efficacy in melanomas harboring the BRAFV600E mutant and also in vemurafenib-resistant melanomas. We designed and synthesized a series of substituted nitric oxide (NO)-releasing quinolone-1,2,4-triazole/oxime hybrids, hypothesizing that the introduction of a STAT3 binding scaffold would augment their cytotoxicity. All the hybrids tested showed a comparable level of in vitro NO production. 7b and 7c exhibited direct binding to the STAT3-SH domain with IC50 of ∼ 0.5 µM. Also, they abrogated STAT3 tyrosine phosphorylation in several cancer cell lines, including the A375 melanoma cell line that carries the BRAFV600E mutation. At the same time, they did not affect the phosphorylation of upstream kinases or other STAT isoforms. 7c inhibited STAT3 nuclear translocation in mouse embryonic fibroblast while 7b and 7c inhibited STAT3 DNA-binding activity in the A375 cell line. Their anti-proliferating activity is attributed to their ability to trigger the production of reactive oxygen species and induce G1 cell cycle arrest in the A375 cell line. Interestingly, 7b and 7c showed robust cell growth suppression and apoptosis induction in two pairs of BRAF inhibitor-naïve (-S) and resistant (-R) melanoma cell lines containing a BRAF V600E mutation. Surprisingly, MEL1617-R cells that are known to be more resistance to MEK inhibition by GSK1120212 than MEL1617-S cells exhibit a similar response to 7b and 7c.

Structure-activity relationship studies of curcumin analogues.

Two series of curcumin analogues, a total of twenty-four compounds, were synthesized and evaluated. The most potent compound, compound 23, showed potent growth inhibitory activities on both prostate and breast cancer lines with IC(50) values in sub-micromolar range, fifty times more potent than curcumin. Curcumin analogues might be potential anti-tumor agents for breast and prostate cancers.

New 1,2,4-triazole-Chalcone hybrids induce Caspase-3 dependent apoptosis in A549 human lung adenocarcinoma cells.

A series of novel 1, 2, 4-triazole/chalcone hybrids was prepared and identified with different spectroscopic techniques. The prepared compounds showed remarkable cytotoxic activity against different cancer cell lines. Compounds 24, 25, 27, 41 and 47 had shown the highest cytotoxicity among the tested compounds against human lung adenocarcinoma A549 cells with IC50 ranging from 4.4 to 16.04 µM compared to cisplatin with IC50 of 15.3 µM. Flow cytometric analysis of the tested compounds showed an increase in the number of apoptotic cells in a dose-dependent manner. The further mechanistic study demonstrated that 1, 2, 4-triazole-chalcone hybrids induced apoptosis via increased level of proapoptotic protein Bax, release of cytochrome c from mitochondria and activation of caspase-3/8/9 proteins. However, general caspase inhibition by the pan-caspase inhibitor, z-VAD-fmk, significantly decreased the apoptosis induced by the tested hybrids, suggesting dependency of apoptosis on activation of the caspase-3 pathway.