Molecular dynamics simulation, synthesis and topoisomerase inhibitory actions of vanillin derivatives: a systematic computational structural integument.

A series of 4-hydroxy-3-methoxy benzaldehyde (vanillin) derivatives (3a-3r) was designed for the principle of Schiff base condensation with several individual sulfanilamide analogues. The inhibitory potencies of the designed compounds were evaluated through molecular docking simulation studies against the targets, breast cancer-topo isomerase-IIα and estrogen receptor-α; and the top scoring poses with higher binding energy were selected to assess the mode of binding and stability of each complex through molecular dynamics simulations. Compounds that remained stable in the active sites of the both target receptors through a number of strong H-bonds and hydrophobic contacts were selected. Based on the computational results, these selected compounds, 3b, 3e and 3f were synthesized and were followed up for structural elucidation attempts, by FT/ATR, 1H NMR and 13C NMR. From the experimental in vitro studies on 3b, 3e and 3f, the following remarkable activities against breast cancer cell line were done; IC50 values of 3b, 3e and 3f were noted, 6.7, 4.3 and 11 ng/mL, respectively. These newly synthesized compounds may be used as novel inhibitors of nuclear receptors with potential therapeutic applications in control of cancer.Communicated by Ramaswamy H. Sarma.

In vitro DNA binding activity and molecular docking reveals pierisin-5 as an anti-proliferative agent against gastric cancer.

Pierisin-5 is a DNA dependent ADP ribosyltransferase (ADRT) protein from the larvae of Indian cabbage white butterfly, Pieris canidia. Interestingly, Pierisin-5 ADP-ribosylates the DNA as a substrate, but not the protein and subsequently persuades apoptotic cell death in human cancer cells. This has led to the investigation on the DNA binding activity of Pierisin-5 using in vitro and in silico approaches in the present study. However, both the structure and the mechanism of ADP-ribosylation of pierisin-5 are unknown. In silico modeled structure of the N-terminal ADRT catalytic domain interacted with the minor groove of B-DNA for ribosylation with the help of ß-NAD+ which lead to a structural modification in DNA (DNA adduct). The possible interaction between calf thymus DNA (CT-DNA) and purified pierisin-5 protein was studied through spectral-spatial studies and the blue shift and hyperchromism in the UV-Visible spectra was observed. The DNA adduct property of pierisin-5 protein was validated by in vitro cytotoxic assay on human gastric (AGS) cancer cell lines. Our study is the first report of the mechanism of DNA binding property of pierisin-5 protein which leads to the induction of cytotoxicity and apoptotic cell death against cancer cell lines.Communicated by Ramaswamy H. Sarma.

Induction of Apoptosis by Pierisin-6 in HPV Positive HeLa and HepG2 Cancer Cells is Mediated by the Caspase-3 Dependent Mitochondrial Pathway.

BACKGROUND: To explore the cytotoxic and apoptotic activity of the pierisin-6 protein in HPV HeLa and HepG2 cell lines. METHODS: In this study, isolation, and purification of cytotoxic Prierisin-6 from the larvae of Pieris napi by affinity column chromatography techniques. Characterization of full-length mRNA of pierisin-6 gene was performed using 3'/5' RACE PCR. The quantitative RT-PCR used to study the developmental stage-specific expression of pierisin-6 mRNA. The most effective concentration of Pierisin-6 protein was determined by measuring cell proliferation. Apoptosis was assessed using AO/Et-Br, Propidium Iodide, and Rhodamine 123 assays, whereas protein levels of caspase 3, cytochrome C were evaluated by ELISA method. Pierisin-6 induced cell cycle arrest was determined using Propidium iodide by FACS. RESULTS: In this study, Pierisin-6, a novel apoptotic protein was found to have cytotoxicity against HeLa, HepG2 human cancer cell lines and L-132 human lung epithelial cell line. Among the target cells, HeLa was the most sensitive to Pierisin-6. Flow cytometry analysis confirms an increased percentage of apoptotic cells in sub G1 phase and cell cycle arrest at S phase. Alteration in the transmembrane potential of mitochondria, Cytochrome c released from the mitochondrial membrane, and caspase substrate assay demonstrated the cleavage of Ac- DEVD-pNA signifying the activation of Caspase-3. These findings suggested that Pierisin-6 significantly induce apoptosis in HeLa and HepG2 cells and is attributed mainly through a mitochondrial pathway by activation of caspases. The developmental and stage-specific expression of pierisin-6 mRNA was one thousand-fold increased from second to third instar larvae and gradually declined before pupation. CONCLUSION: Pierisin-6 represents a promising therapeutic approach for liver cancer patients.