New functionalized 6-thienylpyrimidine-5-carbonitriles as antiproliferative agents against human breast cancer cells

Design, synthesis and molecular docking study of new pyrimidine-based hydrazones with selective anti-proliferative activity against MCF-7 and MDA-MB-231 human breast cancer cell lines

Efforts were directed on the design, synthesis and evaluation of the anticancer activity of some pyrimidine-based hydrazones against two breast cancer cell lines, MCF-7 and MDA-MB-231. Preliminary screening results revealed that some candidates scrutinized for their antiproliferative activities exhibited IC50 values of 0.87 μM-12.91 μM in MCF-7 and 1.75 μM-9.46 μM in MDA-MB-231 cells, indicating almost equal activities on both cell lines and better growth inhibition activities than those of the positive control 5-fluorouracil (5-FU) which displayed IC50 values of 17.02 μM and 11.73 μM respectively. Selectivity of the significantly active compounds was estimated against MCF-10A normal breast cells when compounds 7c, 8b, 9a and 10b exhibited superior activity for cancerous cells than for normal cells when compound 10b presented the best selectivity Index (SI) with respect to both MCF-7 and MDA-MB-231 cancer cells in comparison to the reference drug 5-FU. Mechanisms of their actions were explored by inspecting activation of caspase-9, annexin V staining and cell cycle analysis. It was noticed that compounds 7c, 8b, 8c 9a-c and 10b produced an increase in caspase-9 levels in MCF-7 treated cells with 10b inducing the highest elevation (27.13 ± 0.54 ng/mL) attaining 8.26-fold when compared to control MCF-7 which was higher than that of staurosporine (19.011 ± 0.40 ng/mL). The same compounds boosted caspase-9 levels in MDA-MB-231 treated cells when an increase in caspase-9 concentration reaching 20.40 ± 0.46 ng/mL (4.11-fold increase) was observed for compound 9a. We also investigated the role of these compounds for their increasing apoptosis ability against the 2 cell lines. Compounds 7c, 8b and 10b tested on MCF-7 cells displayed pre-G1 apoptosis and arrested cell cycle in particular at the S and G1 phases. Further clarification of their effects was made by modulating their related activities as inhibitors of ARO and EGFR enzymes when 8c and 9b showed 52.4% and 58.9% inhibition activity relative to letrozole respectively and 9b and 10b showed 36% and 39% inhibition activity of erlotinib. Also, the inhibition activity was verified by docking into the chosen enzymes.

Hydrazinecarbonyl-thiazol-2-acetamides with pronounced apoptotic behavior: synthesis, in vitro/in vivo anti-proliferative activity and molecular modeling simulations

A new series of N-[4-(2-substituted hydrazine-1-carbonyl)thiazole-2-yl]acetamides was synthesized and evaluated in vitro against six human cell lines as antitumor agents. Compounds 20, 21 and 22 showed remarkable inhibition to HeLa (IC₅₀ values of 1.67, 3.81, 7.92 µM) and MCF-7 (IC₅₀ values of 4.87, 5.81, 8.36 µM, respectively) cell growth with high selectivity indices and safety profiles. Compound 20 showed significant decreases in both tumor volume and body weight gain compared to vehicle control, in the solid tumor animal model of Ehrlich ascites carcinoma (EAC) with recovered caspase-3 immuno-expression. Flow cytometry cell analysis showed that 20 exerts anti-proliferative activity in mutant Hela and MCF-7 cell lines through arresting the cell growth at the G1/S phase producing cell death via apoptosis rather than necrosis. To explain the antitumor mode of action of the most active compounds, EGFR-TK and DHFR inhibition assays were carried out. Compound 21 conveyed dual EGFR/DHFR inhibition with IC₅₀ 0.143 (EGFR) and 0.159 (DHFR) µM. Compound 20 showed DHFR inhibition with IC₅₀ 0.262 µM. Compound 22 exhibited the best EGFR inhibitory efficacy with IC₅₀ 0.131 µM. Molecular modelling study revealed that 21 and 22 have binding interactions with EGFR amino acid residues Lys745 and Asp855. Compounds 20 and 21 showed affinity toward DHFR amino acid residues Asn64, Ser59 and Phe31. The ADMET profile and Lipinski's rule of five calculated for these compounds were acceptable. Compounds 20, 21 and 22 could be regarded as promising prototype antitumor agents for further optimization.

Benzoxazole-appended piperidine derivatives as novel anticancer candidates against breast cancer

Novel series of benzoxazole-appended piperidine derivatives were planned, synthesized and screened against two breast cancer cell lines. Considerable antiproliferative activity was observed for screened compounds (IC₅₀ = 33.32 ± 0.2 µM to 7.31 ± 0.43 µM and 1.66 ± 0.08 µM to 12.10 ± 0.57 µM) against MCF-7 and MDA-MB-231 cell lines respectively being more potent than doxorubicin (IC₅₀ = 8.20 ± 0.39 µM and 13.34 ± 0.63 µM respectively). Active compounds were submitted for enzyme inhibition assays when 4d and 7h demonstrated potent EGFR inhibition (0.08 ± 0.002 µM and 0.09 ± 0.002 µM respectively) compared to erlotinib (0.11 ± 0.003 µM). However, no one compound displayed effective ARO inhibition activity as tested compounds were less active than letrozole. Apoptosis inducing ability results implied that apoptosis was provoked by significant stimulation of caspase-9 protein levels (4.25-7.04-fold) upon treatment of MCF-7 cells with 4a, 7h, 9, 12e and 12f. Alternatively, MDA-MB-231 cells treated with 4d, 7a, 12b and 12c considerably increased caspase-9 levels (2.32-4.06-fold). Cell cycle arrest and annexin-V/Propidium iodide assays further confirmed apoptosis when tested compounds arrested cell cycle at various phases and demonstrated high annexin V binding affinity. Docking outcomes proved valuable binding affinities for compounds 4d and 7h to EGFR enzyme while compounds 4a and 12e, upon docking into the active site of ARO, failed to interact with heme, suggesting their inabilities to act as AIs. Therefore, these benzoxazoles can act as promising candidates exhibiting EGFR inhibition and apoptosis-promoting properties.