Naja Naja Oxiana Venom Fraction Selectively Induces ROS-Mediated Apoptosis in Human Colorectal Tumor Cells by Directly Targeting Mitochondria

Anti-Cancer Effect of Moroccan Cobra Naja haje Venom and Its Fractions against Hepatocellular Carcinoma in 3D Cell Culture

Hepatocellular carcinoma (HCC) is the most common primary liver cancer in adults, the fifth most common malignancy worldwide and the third leading cause of cancer related death. An alternative to the surgical treatments and drugs, such as sorafenib, commonly used in medicine is necessary to overcome this public health problem. In this study, we determine the anticancer effect on HCC of Moroccan cobra Naja haje venom and its fraction obtained by gel filtration chromatography against Huh7.5 cancer cell line. Cells were grown together with WI38 human fibroblast cells, LX2 human hepatic stellate cell line, and human endothelial cells (HUVEC) in MCTS (multi-cellular tumor spheroids) models. The hepatotoxicity of venom and its fractions were also evaluated using the normal hepatocytes cell line (Fa2N-4 cells). Our results showed that an anti HCC activity of Moroccan cobra Naja haje venom and, more specifically, the F7 fraction of gel filtration chromatography exhibited the greatest anti-hepatocellular carcinoma effect by decreasing the size of MCTS. This effect is associated with a low toxicity against normal hepatocytes. These results strongly suggest that the F7 fraction of Moroccan cobra Naja haje venom obtained by gel filtration chromatography possesses the ability to inhibit cancer cells proliferation. More research is needed to identify the specific molecule(s) responsible for the anticancer effect and investigate their mechanism of action.

Effects of 3FTx Protein Fraction from Naja ashei Venom on the Model and Native Membranes: Recognition and Implications for the Mechanisms of Toxicity

Three-finger toxins are naturally occurring proteins in Elapidae snake venoms. Nowadays, they are gaining popularity because of their therapeutic potential. On the other hand, these proteins may cause undesirable reactions inside the body′s cells. A full assessment of the safety of Naja ashei venom components for human cell application is still unknown. The aim of the study was to determine the effect of the exogenous application of three-finger toxins on the cells of monocytes (U-937) and promyelocytes (HL-60), with particular emphasis on the modification of their membranes under the influence of various doses of 3FTx protein fraction (0–120 ng/mL). The fraction exhibiting the highest proportion of 3FTx proteins after size exclusion chromatography (SEC) separation was used in the experiments. The structural response of cell membranes was described on the basis of single-component and multi-component Langmuir monolayers that mimicked the native membranes. The results show that the mechanism of protein–lipid interactions depends on both the presence of lipid polar parts (especially zwitterionic type of lipids) and the degree of membrane saturation (the greatest-for unsaturated lipids). The biochemical indicators reflecting the tested cells (MDA, LDH, cell survival, induction of inflammation, LD50) proved the results that were obtained for the model.

SIRT6 promotes angiogenesis and hemorrhage of carotid plaque via regulating HIF-1α and reactive oxygen species

As a member of Sirtuins family, SIRT6 participates in the physiological and pathological progress of DNA repair, anti-aging, metabolism, and so on. Several studies have demonstrated that knockdown of SIRT6 inhibited the development of atherosclerosis (AS), indicated SIRT6 as a protective factor for AS. However, we confirmed SIRT6 was significantly overexpressed in human unstable carotid plaques compared with stable carotid plaques. This result indicated a more complex role of SIRT6 in AS. Furthermore, we constructed mice model with unstable carotid plaque and injected them with SIRT6 overexpressed adeno-associated virus (AAV-SIRT6). AAV-SIRT6 significantly promoted angiogenesis as well as hemorrhage in plaques. In vitro, we demonstrated overexpression of SIRT6 prevented HIF-1α from degradation by deubiquitination at K37 and K532 of HIF-1α, thus promoted the expression of HIF-1α under both normoxia and hypoxia in human umbilical vein endothelial cells (HUVECs). Through regulating HIF-1α, overexpression of SIRT6 promoted invasion, migration, proliferation, as well as tube formation ability of HUVECs. Interestingly, under different conditions, SIRT6 played different roles in the function of HUVECs. Under oxidative stress, another important pathological environment for AS, SIRT6 bound to the promoter of Catalase, a main reactive oxygen species scavenger, and depleted H3K56 acetylation, thus inhibited expression and activity of Catalase at the transcriptional level. Subsequently, inhibited Catalase promoted reactive oxygen species (ROS) under oxidative stress. Accumulated ROS further aggravated oxidative stress injury of HUVECs. On one hand, SIRT6 promoted angiogenesis in plaque via HIF-1α under hypoxia. On the other hand, SIRT6 promoted injury of neovascular via ROS under oxidative stress. It is this process of continuous growth and damage that leads to hemorrhage in carotid plaque. In conclusion, we innovatively confirmed SIRT6 promoted the angiogenesis and IPH via promoting HIF-1α and ROS in different environments, thus disclosed the unknowing danger of SIRT6.

Effect of Bitis gabonica and Dendroaspis angusticeps snake venoms on apoptosis-related genes in human thymic epithelial cells

Background:

Certain environmental toxins permanently damage the thymic epithelium, accelerate immune senescence and trigger secondary immune pathologies. However, the exact underlying cellular mechanisms and pathways of permanent immune intoxication remain unknown. The aim of the present study was to demonstrate gene expressional changes of apoptosis-related cellular pathways in human thymic epithelial cells following exposure to snake venom from Bitis gabonica and Dendroaspis angusticeps.

Methods:

Snake venoms were characterized by analytical methods including reversed phase high-performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, then applied on human thymic epithelial cells (1889c) for 24 h at 10 μg/mL (as used in previous TaqMan Array study). Gene expressional changes restricted to apoptosis were assayed by TaqMan Array (Human Apoptosis Plate).

Results:

The most prominent gene expressional changes were shown by CASP5 (≈ 2.5 million-fold, confirmed by dedicated quantitative polymerase chain reaction) and CARD9 (0.016-fold) for B. gabonica, and BIRC7 (6.46-fold) and CASP1 (0.30-fold) for D. angusticeps.

Conclusion:

The observed apoptotic environment suggests that pyroptosis may be the dominant pathway through which B. gabonica and D. angusticeps snake venoms trigger thymic epithelial apoptosis following envenomation.

Induction of Apoptosis by an Extract of Persian Gulf Marine Mollusc, Turbo Coronatus through the Production of Reactive Oxygen Species in Mouse Melanoma Cells

Objective: A variety of approaches such as surgery, chemotherapy, radiotherapy, hormonal therapy and immunotherapy are used to treat melanomas, but unfortunately in most case, the response is very weak and often side effects are serious. This study concerns selective toxicity of an extract of Turbo coronatus on cells and mitochondria from a syngeneic mouse model of melanoma. Methods: Cells and mitochondria isolated from extra tumoral and melanoma tissues were exposed toa T. coronatus crude extract and fractions obtained by gel-filtration chromatography and assayed for mitochondrial and cellular parameters. Result: Crude extract (375, 750 and 1,500 μg/ml) and fraction 1; F1; (275, 550 and 1100 μg/ml) of T. coronatus extract induced a significant (p<0.05) increase of the reactive oxygen species (ROS) level, swelling of mitochondria, collapse of mitochondrial membrane potential (MMP), release of cytochrome c and caspase-3 activation only in the mitochondria and cells obtained from melanoma but not extra tumoral tissues. In addition, the F1 fraction decreased the percentage of viable cells and induced apoptosis in melanoma cells. Conclusion: For the first time we could demonstrate that the F1 fraction of a T. coronatus extract, selectively induces ROS mediated cytotoxicity by directly targeting mitochondria in melanoma tissues and it may be a suitable candidate for novel drug treatment of malignant melanomas.

Dynamic influence of Rhein lysinate on HeLa cells

In a previous study, it was demonstrated that Rhein lysinate (RHL) inhibited HeLa cell proliferation via a specific mechanism. The aim of the present study was to clarify the mechanism of RHL by investigating its effect on mitochondrial damage and cell apoptosis. The results indicated that RHL inhibited cell growth and proliferation in HeLa cells. HeLa cells treated with RHL developed extensive vacuolization in a dose- and time-dependent manner. Ultrastructure analysis using transmission electron microscopy revealed that the vacuoles observed were damaged mitochondria and endoplasmic reticulum. The effects of RHL on mitochondria were further confirmed by a decrease in mitochondrial membrane potential and increased generation of reactive oxygen species. The mitochondrial proteome was analyzed, and the results demonstrated that the expression of the cytoskeletal protein keratin and dermal papilla derived protein 12 (associated with the oxidation-reduction process), which are associated with mitochondrial structure and function, were decreased compared with the untreated control group. Hoechst staining, flow cytometry and western blotting also revealed that apoptosis was induced at 24 h following RHL treatment. These results confirm that RHL toxicity in HeLa cells is a dynamic process. Vacuolar degeneration appeared in HeLa cells treated with 160 µmol/l RHL during the first 6 h and with the extension of RHL treatment, cell apoptosis was presented at ~24 h in HeLa cells.