Cyclic Peptide Inhibitors of the Tsg101 UEV Protein Interactions Refined through Global Docking and Gaussian Accelerated Molecular Dynamics Simulations.

Tsg101 UEV domain proteins are potential targets for virus infection therapy, especially for HIV and Ebola viruses. Peptides are key in curbing virus transmission, and cyclic peptides have a greater survival time than their linear peptides. To date, the accurate prediction of cyclic peptide-protein receptors binding conformations still is challenging because of high peptide flexibility. Here, a useful approach combined the global peptide docking, Gaussian accelerated molecular dynamics (GaMD), two-dimensional (2D) potential of mean force (PMF), normal molecular dynamics (cMD), and solvated interaction energy (SIE) techniques. Then we used this approach to investigate the binding conformations of UEV domain proteins with three cyclic peptides inhibitors. We reported the possible cyclic peptide-UEV domain protein binding conformations via 2D PMF free energy profiles and SIE free energy calculations. The residues Trp145, Tyr147, and Trp148 of the native cyclic peptide (CP1) indeed play essential roles in the cyclic peptides-UEV domain proteins interactions. Our findings might increase the accuracy of cyclic peptide-protein conformational prediction, which may facilitate cyclic peptide inhibitor design. Our approach is expected to further aid in addressing the challenges in cyclic peptide inhibitor design.

3'-Hydroxy-4'-methoxy-ß-methyl-ß-nitrostyrene inhibits tumor growth through ROS generation and GSH depletion in lung cancer cells.

AIMS: Members of the ß-nitrostyrene family are known to suppress tumor growth, with the underlying mechanisms of ß-nitrostyrene remain mostly unclear. Herein, we synthesized a ß-nitrostyrene derivative, 3'-hydroxy-4'-methoxy-ß-methyl-ß-nitrostyrene (CYT-Rx20), and explored its anticancer activities in human lung cancer cells in vitro and in vivo. MAIN METHODS: Cell viability was measured by XTT assay. Apoptosis was detected by Annexin V/PI staining. Caspase activation was determined by western blotting. ROS (reactive oxygen species), MMP (mitochondrial membrane potential) and mitochondrial mass were determined by flow cytometry. GSH level was detected by ELISA assay. KEY FINDINGS: In this study, we found that CYT-Rx20 significantly reduced cell viability, accompanied by G2/M arrest in lung cancer cells. Increased protein levels of cleaved-caspase families indicated apoptotic cell death upon CYT-Rx20 treatment. Furthermore, increased level of intracellular reactive oxygen species (ROS), loss of mitochondrial membrane potential (ΔΨm), glutathione (GSH) depletion and inhibition of GSH reductase were observed after CYT-Rx20 treatment. The effects of CYT-Rx20 on cell viability and the loss of ΔΨm were significantly reversed when cells were pretreated with thiol antioxidants NAC, GSH, or 2-ME. Finally, xenograft animal study demonstrated that CYT-Rx20 significantly suppressed lung tumor growth in vivo. SIGNIFICANCE: Our data demonstrated that CYT-Rx20 triggered apoptotic cell death in lung cancer cells and suppressed lung tumor growth through GSH depletion, suggesting that CYT-Rx20 may have the potential to be further developed as an anticancer compound for treating lung cancer.

Ovatodiolide of Anisomeles indica Exerts the Anticancer Potential on Pancreatic Cancer Cell Lines through STAT3 and NF-κB Regulation.

Pancreatic cancer is the eighth leading cause of cancer death worldwide. Patients with pancreatic cancer are normally diagnosed at an advanced stage and present poor survival rate. Ovatodiolide (OV), a bioactive macrocyclic diterpenoid isolated from Anisomeles indica, showed cytotoxicity effects in pancreatic cancer cells by inhibiting cell proliferation and inducing apoptosis. Moreover, not only were cell adhesion and invasion markedly suppressed in a dose-dependent manner, but the mRNA expression of matrix metalloproteinase-9 (MMP-9) and focal adhesion kinase (FAK) was also significantly decreased. Western blot analysis indicated that OV potently suppressed the phosphorylation of STAT-3 and its upstream kinase including ERK1/2, P38, and AKT Ser473. Meanwhile, OV inactivated the nuclear factor kappa B (NF-κB) by inhibiting IκB kinase (IKK α/ß) activation and the subsequent suppression of inhibitor of kappa B (IκB) phosphorylation. These results demonstrated that OV could potentially inhibit Mia-PaCa2 cancer cells proliferation and induce apoptosis through modulation of NF-κB and STAT3 pathway. Moreover, OV suppressed cell invasiveness and interfered with cell-matrix adhesion in Mia-PaCa2 cancer cells by reducing MMP-9 and FAK transcription through suppressing NF-κB and STAT3 pathway. Taken together, our findings reveal a new therapeutic and antimetastatic potential of ovatodiolide for pancreatic cancer remedy.

A potential role for Helicobacter pylori heat shock protein 60 in gastric tumorigenesis.

Helicobacter pylori has been found to promote the malignant process leading to gastric cancer. Heat shock protein 60 of H. pylori (HpHSP60) was previously been identified as a potent immunogene. This study investigates the role of HpHSP60 in gastric cancer carcinogenesis. The effect of HpHSP60 on cell proliferation, anti-death activity, angiogenesis and cell migration were explored. The results showed that HpHSP60 enhanced migration by gastric cancer cells and promoted tube formation by umbilical vein endothelial cells (HUVECs); however, HpHSP60 did not increase cell proliferation nor was this protein able to rescue gastric cancer cells from death. Moreover, the results also indicated HpHSP60 had different effects on AGS gastric cancer cells or THP-1 monocytic cells in terms of their expression of pro-inflammatory cytokines, which are known to be important to cancer development. We propose that HpHSP60 may trigger the initiation of carcinogenesis by inducing pro-inflammatory cytokine release and by promoting angiogenesis and metastasis. Thus, this extracellular pathogen-derived HSP60 is potentially a vigorous virulence factor that can act as a carcinogen during gastric tumorigenesis.

Using laser-induced acoustic desorption/electrospray ionization mass spectrometry to characterize small organic and large biological compounds in the solid state and in solution under ambient conditions.

We have coupled laser-induced acoustic desorption (LIAD) with electrospray ionization (ESI) mass spectrometry (LIAD/ESI/MS) to characterize molecules in the solid state and in solution under ambient conditions. To perform an LIAD/ESI analysis, the sample droplet is deposited on the surface of a thin aluminum foil by a micropipette; the rear side of the foil with the sample spot is then irradiated with a pulse from a Nd:YAG IR laser. The resulting shockwave and heat cause the sample on the rear side to change from the condensed phase to the gas phase. The desorbed species then move upward to enter an ESI plume to react with charged solvent species (methanol- and water-related ions and droplets), forming singly or multiply charged analyte ions. A quadrupole/time-of-flight (Q-TOF) mass analyzer attached to the LIAD/ESI source detects the analyte ions to obtain an ESI-like mass spectrum. Both small organic and large biological compounds (including amino acids, peptides, and proteins) were successfully ionized and detected by the LIAD/ESI/MS system. Although native and denatured myoglobin ions were both detected from a liquid sample solution, only the denatured myoglobin ions were detected from a dried sample.