Design, Synthesis and Biological Evaluation of Neocryptolepine Derivatives as Potential Anti-Gastric Cancer Agents.

Natural products play an important role in drug development and lead compound synthesis. Neocryptolepine is a polycyclic quinoline compound isolated from Cryptolepis sanguinolent. The cytotoxicity of neocryptolepine to gastric cancer cells AGS, MKN45, HGC27, and SGC7901 was not very strong, and it also had certain toxicity to gastric mucosa cells GES-1. Therefore, a series of neocryptolepine derivatives were synthesized by the modification of the structure of neocryptolepine, and their cytotoxicity was evaluated. The results showed that compounds C5 and C8 exhibited strong cytotoxicity to AGS cells. The cell colony formation and cell migration experiments suggested that compounds C5 and C8 could inhibit the proliferation and cell migration of AGS and HGC27 cells. Cell cycle and apoptosis experiments showed that compounds C5 and C8 did not cause the apoptosis of AGS and HGC27 cells but, mainly, caused cell necrosis. Compound C5 had no significant effect on AGS and HGC27 cell cycles at low concentration. After treatment with AGS cells for 24 h at high concentration, compound C5 could significantly arrest the AGS cell cycle in the G2/M phase. Compound C8 had no significant effect on the AGS and HGC27 cell cycles. The results of molecular docking and Western blot showed that compounds C5 and C8 might induce cytotoxicity through the PI3K/AKT signaling pathway. Therefore, compounds C5 and C8 may be promising lead compounds for the treatment of gastric cancer.

[Clinical application of laparoscopy-assisted and percutaneous radiofrequency ablation for hepatocellular carcinoma].

OBJECTIVE: To compared the efficacy of laparoscopy- assisted radiofrequency ablation (LRFA) and percutaneous radiofrequency ablation (PRFA) for the treatment of hepatocellular carcinoma (HCC). METHODS: Between September, 2013 and September, 2016, a total of 60 HCC patients with 78 tumor nodules underwent LRFA (30 cases with 46 tumor nodules) and PRFA (30 cases with 32 tumor nodules) in our hospital. The patients were followed up for 3 years to compare the complete ablation rate, serious complications, recurrence rate and long-term survival rate between the two groups. RESULTS: The patients receiving LRFA had a complete ablation rate of 95.65% (44/46), significantly higher than the rate of 93.75% (30/32) in PRFA group (P > 0.05). Significant differences were found between LRFA and PRFA groups in the incidence of serious complications [0 vs 6.7% (2/30), P < 0.05] and recurrence rate [13.33% (4/30) vs 23.33% (7/30), P < 0.05]. The 1-and 3-year overall survival rates of the patients were 96.15% and 55.12% in LRFA group and 93.73% and 48.54% in PRFA group, respectively (P > 0.05). CONCLUSIONS: Both LRFA and PRFA are effective for HCC treatment, but is associated with a lower recurrence rate, fewer serious complications, a better treatment safety and a better applicability for tumor in difficult locations.

Weak power frequency magnetic fields induce microtubule cytoskeleton reorganization depending on the epidermal growth factor receptor and the calcium related signaling.

We have shown previously that a weak 50 Hz magnetic field (MF) invoked the actin-cytoskeleton, and provoked cell migration at the cell level, probably through activating the epidermal growth factor receptor (EGFR) related motility pathways. However, whether the MF also affects the microtubule (MT)-cytoskeleton is still unknown. In this article, we continuously investigate the effects of 0.4 mT, 50 Hz MF on the MT, and try to understand if the MT effects are also associated with the EGFR pathway as the actin-cytoskeleton effects were. Our results strongly suggest that the MF effects are similar to that of EGF stimulation on the MT cytoskeleton, showing that 1) the MF suppressed MT in multiple cell types including PC12 and FL; 2) the MF promoted the clustering of the EGFR at the protein and the cell levels, in a similar way of that EGF did but with higher sensitivity to PD153035 inhibition, and triggered EGFR phosphorylation on sites of Y1173 and S1046/1047; 3) these effects were strongly depending on the Ca2+ signaling through the L-type calcium channel (LTCC) phosphorylation and elevation of the intracellular Ca2+ level. Strong associations were observed between EGFR and the Ca2+ signaling to regulate the MF-induced-reorganization of the cytoskeleton network, via phosphorylating the signaling proteins in the two pathways, including a significant MT protein, tau. These results strongly suggest that the MF activates the overall cytoskeleton in the absence of EGF, through a mechanism related to both the EGFR and the LTCC/Ca2+ signaling pathways.

DOSIMETRIC VARIATION IN HUMAN EXPOSURE TO 20 MHZ-3 GHZ ELECTROMAGNETIC FIELDS DUE TO CHANGES IN DIELECTRIC PROPERTIES.

Specific energy absorption rate (SAR) is often used to assess human exposure to electromagnetic radiation. SAR is strongly related to incident field parameters, characteristics of the body exposed, ground effects and other factors. In this study, changes in dielectric properties, due to health and age status, were taken into account in the simulation of SAR in a Chinese male model exposed to eight orthogonal plane-wave configurations at the frequency range of 20 MHz-3 GHz. The results show that changes in dielectric properties can cause variations in SAR. Moreover, the variation in SAR was influenced by frequency, electric polarisation and incident direction. Therefore, it is of great significance to distinguish the frequency and exposure configuration when a change in dielectric properties is applied in the evaluation of SAR. In addition, more general cases with a random change in dielectric properties should be performed, which are more realistic.

[Effect of 33 Hz Pulsed Electric Field on Insulin Amyloidosis].

The destabilizing of protein leads to self-aggregation and fibrillar assemblies. In the form of amyloid fibrils or fibril precursors, protein not only lacks the original biological function but also may be harmful to organisms. Stimulated by an intense electric field, the secondary structures of protein can be disturbed and transfer to aggregations or unfolding conformations, which may inhibit the fibrillation process. As a model for disease-associated amyloids, insulin fibrillation is proposed to occur via partial unfolding of a monomeric intermediate. This project is focusing on in-vitro studies employing a 33 Hz pulsed electric field (PEF) to see if there is possible causal connection between insulin fibrillation and PEF exposure. Thioflavin T (ThT)-fluorescence, circular dichroism(CD) and transmission electron microscopy (TEM) techniques were employed regarding the effects of exposure duration and field intensity of the PEF on the fibrillation mechanism of insulin. The results confirm that the PEF exposed insulin molecules may primitively have a slight change in its native structure, causing aggregation. The aggregates in the PEF exposed insulin solution are difficult to dissolve to facilitate the unfolding of insulin molecules. When the molecular conformation converts from α-helical to ß-sheet structure, the fibrillation velocity in the PEF exposed insulin is accelerated by the PEF exposure thereby shortening the lifetime of the intermediates. The morphology of mature fibrils changes from long twisted fibrils to shorter and less matured fibrils. All these effects enhance when the exposure duration and electric intensity increase. The investigated evidences suggest that the PEF can inhibit insulin amyloidosis.

Weak power frequency magnetic field acting similarly to EGF stimulation, induces acute activations of the EGFR sensitive actin cytoskeleton motility in human amniotic cells.

In this article, we have examined the motility-related effects of weak power frequency magnetic fields (MFs) on the epidermal growth factor receptor (EGFR)-sensitive motility mechanism, including the F-actin cytoskeleton, growth of invasive protrusions and the levels of signal molecules in human amniotic epithelial (FL) cells. Without extracellular EGF stimulation, the field stimulated a large growth of new protrusions, especially filopodia and lamellipodia, an increased population of vinculin-associated focal adhesions. And, an obvious reduction of stress fiber content in cell centers was found, corresponding to larger cell surface areas and decreased efficiency of actin assembly of FL cells in vitro, which was associated with a decrease in overall F-actin content and special distributions. These effects were also associated with changes in protein content or distribution patterns of the EGFR downstream motility-related signaling molecules. All of these effects are similar to those following epidermal growth factor (EGF) stimulation of the cells and are time dependent. These results suggest that power frequency MF exposure acutely affects the migration/motility-related actin cytoskeleton reorganization that is regulated by the EGFR-cytoskeleton signaling pathway. Therefore, upon the MF exposure, cells are likely altered to be ready to transfer into a state of migration in response to the stimuli.

[Effect of 50 Hz power frequency magnetic field on microfilament cytoskeleton assembly of human amnion FL cells].

OBJECTIVE: Investigations were carried out to understand the effect of 50 Hz power frequency magnetic field on microfilament assembly of human amniotic cells and on expression of actin and epidermal growth factor receptor. METHODS: Human amnion FL cells were exposed to 0.1, 0.2, 0.3, 0.4, 0.5 mT power frequency magnetic field for 30 minutes. Microfilaments were marked using Phalloidin-TRITC, and then were observed under a fluorescence microscope. An optical method was used to detect the relative content of microfilament in cells. A scanning electron microscope was used to detect the cell shape. The content of actin and epidermal growth factor receptor in the preparation of the detergent-insoluble cytoskeleton were measured by western-blotting to analyse the potential mechanism of the change induced by magnetic field. RESULTS: Intracellular stress fibers were found to decrease after exposing cells to a 0.2 mT power frequency magnetic field for 30 minutes. New microfilament and filopodia bundles appeared at the cell periphery after exposure, but the detected total F-actin content per cell was not significantly changed, detected by a F-actin-specific dye. The change in the amount of microfilaments caused by the field could be recovered 2 hours later when the field was withdrawn. The mean height of microfilament cytoskeleton decreased from (12.37 +/- 1.28) microm to (9.97 +/- 0.38) microm (t = 6.96, P > 0.05) after exposure using a confocal microscope. The cell shapes became more flat and lamellipodia appeared after exposure observed by a scanning electron microscope. By using Western blotting method, the intracellular contents of epidermal growth factor receptor and of actin in the preparation of the detergent-insoluble cytoskeleton which are associated with high-affinity epidermal growth factor receptors, increased about (31.2 +/- 4.1)% (t = 17.10, P < 0.05) and (16.8 +/- 2.3)% (t = 16.68, P < 0.05) respectively, compared with that of the control. CONCLUSION: These results suggest that a short time exposure to a 0.2 mT power frequency magnetic field induces re-organization of microfilament in human amnion FL cells. These changes could be recovered by field withdraw and may have something with the clustering of epidermal growth factor receptors induced by magnetic field.

EGF receptor clustering is induced by a 0.4 mT power frequency magnetic field and blocked by the EGF receptor tyrosine kinase inhibitor PD153035.

Atomic force microscopy (AFM), transmission electron microscopy (TEM), and confocal laser scanning microscopy were used to investigate the effects of a 50 Hz 0.4 mT magnetic field (MF) on the clustering of purified epidermal growth factor receptors (EGFRs) and EGFRs in Chinese hamster lung (CHL) cell membrane. The results demonstrate that exposing purified EGFRs to the MF for 30 min induces receptor clustering. The peak height of apparent clusters increased from 1.42 +/- 0.18 (sham-exposed) to 3.08 +/- 0.38 nm (exposed) while the mean half-width increased from 21.7 +/- 2.2 to 33.0 +/- 4.0 nm. A similar effect was also observed by TEM. Treatment of purified EGFR with PD153035 (PD), an EGFR-specific tyrosine kinase (TK) inhibitor, inhibited the MF-induced EGFR clustering of the purified proteins, an effect also observed for the receptors in cell membrane in the absence of EGF. These results strongly suggest that the 50 Hz 0.4 mT MF interferes with the EGFR signaling pathway, most likely by interacting with the cytoplasmic TK domain.