Synthesis of enamino-2-oxindoles via conjugate addition between α-azido ketones and 3-alkenyl oxindoles: Cytotoxicity evaluation and apoptosis inducing studies.

A facile method for the construction of double bond between 3-ylidene oxindoles and α-azido ketones has been successfully accomplished with a mild base. This method features azido reduction with concomitant double bond formation to provide the new class of bioactive enamino-2-oxindoles. These new compounds were screened for their in vitro cytotoxic potential on selected human cancer cell lines such as colon, lung, breast, and cervical cancer cells. Among them, representative compounds 3a, 3h, 3k, 3p, 3w and 3x showed notable cytotoxicity profile with IC50 values ranging from 1.40 ±â€¯0.10 to 28.7 ±â€¯0.36 µM. Compound 3k displayed most potent cytotoxicity against lung cancer (NCI-H460) cells with an IC50 value of 1.40 ±â€¯0.10 µM. 3k also arrested the G2/M phase of the cell cycle and induced distinctive apoptotic features on lung cancer cells. The apoptosis induction is supported by various cellular assays such as AO/EB, DAPI, and DCFDA staining studies including clonogenic assay. Extent of apoptosis was also analyzed by Annexin binding and JC-1 staining. Moreover, this method is amenable for the generation of a library of new class of stable bioactive enamino-2-oxindoles.

Microwave-assisted one-pot synthesis of new phenanthrene fused-tetrahydrodibenzo-acridinones as potential cytotoxic and apoptosis inducing agents.

An expeditious microwave-assisted one-pot synthesis of new cytotoxic phenanthrene fused-tetrahydrodibenzo-acridinones has been successfully accomplished. This protocol offers wide substrate scope, catalyst-free synthesis, atom-economy, simple recrystallization, high yields, and ethanol was used as green solvent. These new compounds were tested for their in vitro cytotoxicity against cervical (HeLa), prostate (PC-3), fibrosarcoma (HT-1080), ovarian (SKOV-3) cancer cells, and were safer to normal (Hek-293T) kidney cell line. All the compounds have displayed significant cytotoxicity profile, among them 8m being the most potent compound with an IC50 0.24 ±â€¯0.05 µM against SKOV-3 ovarian cancer cells. Flow cytometry analysis revealed that cells were blocked at the G2/M phase of the cell cycle. The effect of 8m on F-actin polymerisation was also studied. Hoechst staining clearly showed the decreased number of viable cells and indicated apoptosis progression. Compound 8m caused the collapse of mitochondrial membrane potential as observed via JC-1 staining and also enhanced the generation of reactive oxygen species. The increase of caspase-3 activation by 3.7 folds supported the strong apoptosis induction. In addition, an in vitro 3D-spheroid progression assay was performed with 8m that significantly suppressed the tumor cells.

Synthesis of 1,2,4-triazole-linked urea/thiourea conjugates as cytotoxic and apoptosis inducing agents.

A new series of 1,2,4-triazole-linked urea and thiourea conjugates have been synthesized and evaluated for their in vitro cytotoxicity against selected human cancer cell lines namely, breast (MCF-7, MDA-MB-231), lung (A549) prostate (DU145) and one mouse melanoma (B16-F10) cell line and compared with reference drug. The compound 5t showed significant cytotoxicity on MCF-7 breast cancer cell line with a IC50 value of 7.22 ±â€¯0.47 µM among all the tested compounds. Notably, induction of apoptosis by compound 5t on MCF-7 cells was evaluated using different staining techniques such as acridine orange/ethidium bromide (AO/EB), annexin V-FITC/PI, and DAPI. Further, clonogenic assay indicates the inhibition of colony formation on MCF-7 cells by compound 5t. Moreover, the flow-cytometric analysis also revealed that compound 5t caused the arrest of cells at G0/G1 phase of cell cycle. In addition, the compounds when tested on normal human cells (L-132) were found to be safer with low cytotoxicity profile.

Sulfamic acid promoted one-pot synthesis of phenanthrene fused-dihydrodibenzo-quinolinones: Anticancer activity, tubulin polymerization inhibition and apoptosis inducing studies.

A facile one-pot method for the synthesis of new phenanthrene fused-dihydrodibenzo-quinolinone derivatives has been successfully accomplished by employing sulfamic acid as catalyst. These new compounds were evaluated for their in vitro cytotoxic potential against human lung (A549), prostate (PC-3 and DU145), breast (MCF-7) and colon (HT-29 and HCT-116) cancer cell lines. Among all the tested compounds, one of the derivatives 8p showed good anti-proliferative activity against A549 lung cancer cell line with an IC50 of 3.17 ±â€¯0.52 µM. Flow cytometric analyses revealed that compound 8p arrested both Sub G1 and G2/M phases of cell cycle in a dose dependent manner. The compound 8p also displayed significant inhibition of tubulin polymerization and disruption of microtubule network (IC50 of 5.15 ±â€¯0.15 µM). Molecular docking studies revealed that compound 8p efficiently interacted with critical amino acid Cys241 of the α/ß-tubulin by a hydrogen bond (SH…O = 2.4 Å). Further, the effect of 8p on cell viability was also studied by AO/EB, DCFDA and DAPI staining. The apoptotic characteristic features revealed that 8p inhibited cell proliferation effectively through apoptosis by inducing the ROS generation. Analysis of mitochondrial membrane potential through JC-1 staining and annexin V binding assay indicated the extent of apoptosis in A549 cancer cells.

Synthesis of substituted phenanthrene-9-benzimidazole conjugates: Cytotoxicity evaluation and apoptosis inducing studies.

A series of new phenanthrene-9-benzimidazole conjugates has been synthesized by condensing phenanthrene aldehydes with various substituted o-phenylenediamines. The title compounds were evaluated for their in vitro cytotoxic potential against various human cancer cell lines like breast (BT-549), prostate (PC-3 and DU145), triple negative breast cancer (MDA-MB-453), and human colon cancer (HCT-116 and HCT-15) cells. Among the tested compounds, 10o displayed significant in vitro cytotoxic activity against PC-3 prostate cancer cells with an IC50 value of 6.32 ± 0.09 µM. Further, the cell cycle analysis indicated that it blocks G2/M phase of the cell cycle in a dose dependent manner. In order to determine the effect of the compound 10o on cell viability; phase contrast microscopy, AO/EB staining, DAPI staining, and DCFDA staining studies were performed. In these studies, apoptotic features were clearly observed indicating that the compound inhibited cell proliferation by apoptosis. JC-1 staining and annexin binding assays indicated the extent of apoptosis in PC-3 cells. Further, relative viscosity measurements and molecular docking studies indicated that these compounds bind to DNA by intercalation.

Conventional and microwave-assisted synthesis of new 1H-benzimidazole-thiazolidinedione derivatives: A potential anticancer scaffold.

A series of new benzimidazole bearing thiazolidinedione derivatives has been designed, synthesized by using conventional as well as microwave-assisted methods. Microwave-assisted synthesis caused a significant reduction in the reaction times and improvement in the yields of all the derivatives. All the new synthesized compounds were evaluated for their in vitro cytotoxic potential against selected human cancer cell lines of breast (MDAMB-231), prostate (PC-3), cervical (HeLa), lung (A549) and bone (HT1080) along with a normal kidney cells (HeK-293T). The compounds 17n, 17p and 17q were found to be potent cytotoxic with IC50 values in the range of 0.096-0.63 µM on PC-3, HeLa, A549 and HT1080 cancer cells. Most of the compounds have found to be safe on normal HeK-293T kidney cells in comparison to cancer cells. The treatment of cells with 17p and 17q showed the typical apoptotic morphological features like fragmentation and shrinkage of nuclei. Further, test compounds resulted in inhibition of cell migration through disruption of F-actin protein assembly. Hoechst, DCFH-DA staining, mitochondrial membrane and annexin binding assays revealed that the cancer cell proliferation was inhibited through induction of apoptosis in A549 cells.

Design and synthesis of 1,2,3-triazolo-phenanthrene hybrids as cytotoxic agents.

A series of new 1,2,3-triazolo-phenanthrene hybrids has been synthesized by employing Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. These compounds were evaluated for their in vitro cytotoxic potential against various human cancer cell lines viz. lung (A549), prostate (PC-3 and DU145), gastric (HGC-27), cervical (HeLa), triple negative breast (MDA-MB-231, MDA-MB-453) and breast (BT-549, 4T1) cells. Among the tested compounds, 7d displayed highest cytotoxicity against DU145 cells with IC50 value of 1.5±0.09µM. Further, the cell cycle analysis shown that it blocks G0/G1 phase of the cell cycle in a dose dependent manner. In order to determine the effect of compound on cell viability, phase contrast microscopy, AO/EB, DAPI, DCFDA and JC-1 staining studies were performed. These studies clearly indicated that the compound 7d inhibited the cell proliferation of DU145 cells. Relative viscosity measurements and molecular docking studies indicated that these compounds bind to DNA by intercalation.

Synthesis of 2,3,6,7-tetramethoxyphenanthren-9-amine: An efficient precursor to access new 4-aza-2,3-dihydropyridophenanthrenes as apoptosis inducing agents.

A new route for the synthesis of novel 2,3,6,7-tetramethoxy phenanthrene amine precursor has been successfully accomplished. Subsequently, this amine precursor has been directly utilized for the synthesis of a new series of 4-aza-2,3-dihydropyridophenanthrene derivatives via a three component reaction with tetronic acid and substituted aldehydes. These compounds were evaluated for their cytotoxic potential against human lung (A549), prostate (PC-3 and DU145), breast (MDA-MB-231 and 4T1), gastric (HGC-27), colon (Caco-2) and cervical (HeLa) cancer cell lines. Compound 10l showed significant anticancer profile against DU145 cell line with an IC50 value of 2.6 ± 0.34 µM. Disruption of F-actin cytoskeleton structure and cell migration inhibition in DU145 cells clearly indicate that the tumor progression and metastasis are affected by this compound (10l). Cell cycle analysis revealed that it arrests the cells in G2/M phase. Acridine orange/ethidium bromide (AO/EB) staining, Hoechst staining and annexin-V binding assays showed that cell proliferation is inhibited through induction of apoptosis. Moreover, its treatment leads to collapse of the mitochondrial membrane potential (DΨm).

One-pot synthesis of podophyllotoxin-thiourea congeners by employing NH2SO3H/NaI: Anticancer activity, DNA topoisomerase-II inhibition, and apoptosis inducing agents.

A facile one-pot method for the synthesis of novel podophyllotoxin-thiourea congeners has been developed by using NH2SO3H/NaI system. Interestingly, 4ß-azido podophyllotoxin reduction with concomitant aryl isothiocyanates coupling under mild reaction conditions has been achieved. These compounds have been investigated for their in vitro cytotoxicity against A549, MDA MB-231, DU-145, LNCaP, and HGC-27 cancer cell lines. Some of the representative compounds have selectively exhibited cytotoxicity on DU-145 (human prostate cancer) cells and the most potent compound was 4a (IC50 of 0.50 ± 0.03 µM) with optimal safety therapeutic window (81.7 fold) on normal human prostate cell line (RWPE-1, IC50 of 40.85 ± 0.78). The flow-cytometric analysis of the compound 4a in prostate cancer cells indicated a strong G2/M-phase arrest and significant topoisomerase II inhibition activity. Furthermore, these compounds induce apoptosis as observed by Acridine Orange and Ethidium Bromide (AO/EB) staining and Annexin V binding assay. Molecular docking results of the title compounds with topoisomerase-IIα were presented as theoretical support for the experimental data.