Utilizing Estra-1,3,5,16-Tetraene Scaffold: Design and Synthesis of Nitric Oxide Donors as Chemotherapeutic Resistance Combating Agents in Liver Cancer.

A new series of nitric oxide-releasing estra-1,3,5,16-tetraene analogs (NO-∆-16-CIEAs) was designed and synthesized as dual inhibitors for EGFR and MRP2 based on our previous findings on estra-1,3,5-triene analog NO-CIEA 17 against both HepG2 and HepG2-R cell lines. Among the target compounds, 14a (R-isomer) and 14b (S-isomer) displayed potent anti-proliferative activity against both HepG2 and HepG2-R cell lines in comparison to the reference drug erlotinib. Remarkably, compound 14a resulted in a prominent reduction in EGFR phosphorylation at a concentration of 1.20 µM with slight activity on the phosphorylation of MEK1/2 and ERK1/2. It also inhibits MRP2 expression in a dose-dependent manner with 24% inhibition and arrested the cells in the S phase of the cell cycle. Interestingly, compound 14a (estratetraene core) exhibited a twofold increase in anti-proliferative activity against both HepG2 and HepG2-R in comparison with the lead estratriene analog, demonstrating the significance of the designed ∆-16 unsaturation. The results shed a light on compound 14a and support further investigations to combat multidrug resistance in chemotherapy of hepatocellular carcinoma patients.

Cytotoxicity, Antimicrobial, and In Silico Studies of Secondary Metabolites From Aspergillus sp. Isolated From Tecoma stans (L.) Juss. Ex Kunth Leaves.

Endophytes are prolific producers of privileged secondary metabolites with diverse therapeutic potential, although their anticancer and antimicrobial potential still have a room for further investigation. Herein, seven known secondary metabolites namely, arugosin C (1), ergosterol (2), iso-emericellin (3), sterigmatocystin (4), dihydrosterigmatocystin (5), versicolorin B (6), and diorcinol (7) were isolated from the rice culture of Aspergillus sp. retrieved from Tecoma stans (L.) Juss. ex Kunth leaves. Their anticancer and antimicrobial activities were evaluated in MTT and agar well diffusion assays, respectively. The cytotoxicity results showed that metabolite 3 displayed the best viability inhibition on the MCF-7 breast cancer cells with IC50 = 225.21 µM, while 5 on the HepG2 hepatocellular carcinoma cells with IC50 = 161.81 µM. 5 demonstrated a 60% apoptotic mode of cell death which is virtually correlated to its high docking affinity to Hsp90 ATP binding cleft (binding score -8.4 Kcal/mol). On the other side, metabolites 4 and 5 displayed promising antimicrobial activity especially on Pseudomonas aeruginosa with MIC = 125 µg/ml. The observed effect may be likely related to their excellent in silico inhibition of the bacterial DNA-gyrase kinase domain (binding score -10.28 Kcal/mol). To the best of our knowledge, this study is the first to report the promising cytotoxic and antibacterial activities of metabolites 3, 4, and 5 which needs further investigation and renovation to therapeutic leads.

Design, synthesis, and biological evaluation of new pyrazoloquinazoline derivatives as dual COX-2/5-LOX inhibitors.

A new series of pyrazoloquinazoline derivatives equipped with different chalcones was designed, synthesized, and identified through 1 H nuclear magnetic resonance (NMR), 13 C NMR, and infrared spectroscopic techniques. Our design strategy of the quinazolinone-privileged scaffold as a new scaffold was based on merging pharmacophores previously reported to exhibit cyclooxygenase-2 (COX-2)/5-lipoxygenase (5-LOX) inhibitory activity. All the newly synthesized derivatives were biologically evaluated for COX and 5-LOX inhibitory activity and COX-2 selectivity, using celecoxib and zileuton as reference drugs, as they exhibited promising anti-inflammatory activity. Compound 3j was found to be the most promising derivative, with IC50 values of 667 and 47 nM against COX-1 and COX-2, respectively, which are superior to that of celecoxib (IC50 value against COX-2 = 95 nM), showing an SI of 14.2 that was much better than celecoxib. Compounds 3f and 3h exhibited COX-1 inhibition, with IC50 values of 1,485 and 684 nM, respectively. The synthesized compounds showed a significant inhibitory activity against 5-LOX, with IC50 values ranging from 0.6 to 4.3 µM, where compounds 3f and 3h were found to be the most potent derivatives, with IC50 values of 0.6 and 1.0 µM, respectively, in comparison with that of zileuton (IC50 = 0.8 µM). These promising derivatives, 3f, 3h, and 3j, were further investigated in vivo for anti-inflammatory, gastric ulcerogenic effects, and prostaglandin production (PGE2) in rat serum. The molecular docking studies concerning the binding sites of COX-2 and 5-LOX revealed similar orientation, compared with reported inhibitors, which encouraged us to design new leads targeting COX-2 and 5-LOX as dual inhibitors, as a new avenue in anti-inflammatory therapy.

Design and synthesis of pyrazolo[3,4-d]pyrimidinone derivatives: Discovery of selective phosphodiesterase-5 inhibitors.

A novel series of 1,6-disubstituted pyrazolo[3,4-d]pyrimidin-7-one derivatives, 2a-h, 4a-d, 5 and 6, were successfully synthesized, which showed promising, and potent inhibition of phosphodiesterase 5 (PDE5). The inhibitory activities of 5, 4b, 2a, 2d, 2f, 4d and 4a against PDE5 were similar to that of sildenafil (100%). These compounds exhibited potent relaxant effects on isolated rat cavernosum tissue with pEC50 values ranging from 8.31 to 5.16 µM. Pyrazolo[3,4-d]pyrimidin-7-one scaffolds have been rationally designed via consecutive molecular modelling studies prior to their synthesis and biological evaluation. In addition, the results of the pharmacophore-based virtual screening revealed that 1v0p_PVB might have promising activity as a PDE-5 inhibitor.

Design, synthesis and biological study of hybrid drug candidates of nitric oxide releasing cucurbitacin-inspired estrone analogs for treatment of hepatocellular carcinoma.

Development of hybrid drug candidates is well known strategy for designing antitumor agents. Herein, a novel class of nitric oxide donating cucurbitacin inspired estrone analogs (NO-CIEAs) were designed and synthesized as multitarget agents. Synthesized analogs were initially evaluated for their anti-hepatocellular carcinoma activities. Among the tested analogs, NO-CIEAs 17 and 20a exhibited more potent activity against HepG2 cells (IC50 = 4.69 and 12.5 µM, respectively) than the reference drug Erlotinib (IC50 = 25 µM). Interestingly, NO-CIEA 17 exerted also a high potent activity against Erlotinib-resistant HepG2 cell line (HepG2-R) (IC50 = 8.21 µM) giving insight about its importance in drug resistance therapy. Intracellular measurements of NO revealed that NO-CIEAs 17 and 20a showed a significant increase in NO production in tumor cells after 1 h of incubation comparable to the reference prodrug JS-K. Flow cytometric analysis showed that both NO-CIEAs 17 and 20a mainly arrested the HepG2 cells in the G0/G1 phase. Also, In-Cell Based ELISA screening showed that NO-CIEA 17 resulted in a potential inhibitory activity towards the EGFR and MAPK (25% and 29% inhibition compared to untreated control cells, respectively). This data suggests the binding ability of NO-CIEA 17 to the EGFR and ERK to be well correlated along with the docking and cellular studies. Also, treatment of HepG2-R cells with NO-CIEA 17 showed a potential reduction of MRP2 expression in a dose dependent manner providing a significant impact on the chemotherapeutic resistance. Overall, the current study provides a potential new approach for the discovery of a novel antitumor agent against HCC.

Synthesis of new pyrazoles and pyrozolo [3,4-b] pyridines as anti-inflammatory agents by inhibition of COX-2 enzyme.

New pyrazoles and pyrazolo[3,4-b] pyridines were synthesized and their structure was confirmed by elemental analyses as well as IR, 1H NMR, 13C NMR, and mass spectral data. All the newly synthesized derivatives were evaluated in vitro for inhibitory activity against COX-1 and COX-2 enzymes and their IC50 values were calculated, most of the derivatives showed good inhibitory activity with derivatives IVb, IVh and IVJ showing inhibitory activity better than celecoxib. Moreover, the eight most potent derivatives IVa, IVb, IVc, IVd, IVe, IVh, IVJ, and IVL were selected for in vivo assay to measure their effect on paw edema in rates and their ulcerogenic effect. Compounds IVa, IVb and IVc were found to be the most active and selective as COX-2 inhibitors and most effective in protection from edema, they were also found to have lowest ulcerogenic effect among all derivatives.

Design and synthesis of pyrazolo[3,4-d]pyrimidines: Nitric oxide releasing compounds targeting hepatocellular carcinoma.

A new series of pyrazolo[3,4-d]pyrimidines tethered with nitric oxide (NO) producing functionality was designed and synthesized. Sulforhodamine B (SRB) protein assay revealed that NO releasing moiety in the synthesized compounds significantly decreased the cell growth more than the des-NO analogues. Compounds 7C and 7G possessing N-para-substituted phenyl group, released the highest NO concentration of 4.6% and 4.7% respectively. Anti-proliferative activity of synthesized compounds on HepG2 cell line identified compounds 7h, 7p, 14a and 14b as the most cytotoxic compounds in the series of IC50=3, 5, 3 and 5µM, respectively, compared to erlotinib as a reference drug (IC50=25µM). Flow cytometry studies revealed that 7h arrested the cells in G0/G1 phase of cell cycle while 7p arrested the cells in S phase. Moreover, docking study of the synthesized compounds on EGFR (PDB code: 1M17) and cytotoxicity study indicated that N-1 phenyl para substitution, pyrazole C-3 alkyl substitution and tethering the nitrate moiety through butyl group had a significant impact on the activity.

Anticancer and radiosensitizing evaluation of some new pyranothiazole-Schiff bases bearing the biologically active sulfonamide moiety.

The present work reports the synthesis of some new Schiff bases, 5-(substituted benzylideneamino)-6-cyano-7H-7-(4-methoxyphenyl)-2-(4-sulphamoylphenylamino) pyrano[2,3-d]thiazole (5-15). The design of the structures of these compounds complies with the general pharmacophoric requirements for CA inhibiting anticancer drugs. The newly synthesized compounds were evaluated for their in vitro anticancer activity against human breast cancer cell line (MCF7). Most of the screened compounds showed interesting cytotoxic activities compared to doxorubicin as a reference drug. Compounds 4, 6-8 and 11 (IC(50): 27.51, 10.25, 9.55, 9.39 and 9.70 µM, respectively) exhibited higher cytotoxic activities than the reference drug doxorubicin (IC(50): 32.00 µM). Additionally, the previously mentioned compounds were evaluated again for their ability to enhance the cell killing effect of γ-radiation.

Novel thiophenes, thienopyrimidines, and triazolothienopyrimidines for the evaluation of anticancer and augmentation effects of gamma-radiation.

New derivatives of thiophenes 2, 12, iminoaminothieno[2,3-d]pyrimidines 3, 5, and 6, triazolothieno[2,3-d]pyrimidines 8-11, pyrazolo- and triazinothieno[2,3-d]pyrimidines 4, 7, respectively, have been prepared by different synthetic procedures. Structure elucidation of the newly synthesized compounds was carried out via elemental analyses and spectral data. The antitumor activity of compounds 2, 3, and 9-12 was evaluated against in-vitro cell lines (HEPG-2 and MCF-7). Compounds 2, 3, 10, 11, and 12 showed significant in-vitro cytotoxic activity against hepatocellular carcinoma (HEPG-2) compared to the reference drug Doxorubicin. Compound 2 showed significant in-vitro cytotoxic activity against breast cancer (MCF-7) cells compared to the reference drug Doxorubicin. The augmenting effect of gamma-radiation was assessed; here, compounds 2, 3, 10, and 11 showed the most potent in-vitro anticancer activity.