Resistance of cervical adenocarcinoma cells (HeLa) to venom from the scorpion Centruroides limpidus limpidus

In-vitro Study of Hottentotta Schach Crude Venom Anticancer Effects on MCF-7 and Vero Cell Lines

Scorpion venoms contain potentially useful pharmacological agents. Several studies demonstrate that the venoms of some scorpions induce apoptosis and inhibit the growth of cancer cells; therefore, they have been investigated for isolating anticancer components. In this study, antitumor effects of Hottentotta schach crude venom on MCF-7 (breast cancer cell line) as test group and Vero (African green monkey kidney normal cell line) as control group were analyzed. Cell toxicity was analyzed using MTT and neutral red (NR) uptake assays and apoptosis induction was analyzed using comet assay and caspase-3 activity. Oxidative stress following Hottentotta schach crude venom treatment was analyzed using nitrite oxide (NO) determination assay, reduced glutathione (GSH) and catalase enzyme activity assays. Results showed that crude venom (25-200 μg/mL) induced apoptosis and inhibited the growth of MCF-7 and to a lesser extent in Vero cell lines. Nitrite oxide concentration increased while glutathione concentration and catalase enzyme activity were decreased in MCF-7 cells; however, results in Vero cells were reversed completely. It can be concluded that Hottentotta schach crude venom disturbs the oxidation and reduction potential in cancer cells and ultimately induce apoptosis. So this venom can be used as a good source for isolation and designing new anticancer drugs.

Biochemical characterization and in vitro biological activities of the epithelial cell extracts from Hypanus dipterurus spine

Ocean organisms live in competitive environments that demand the production of poisons and toxins. In some cases, these substances have been used in the pharmaceutical industry for human disease treatments. Most fish poisons generally have potent cytolytic activity, probably through cardiovascular and neuromuscular effects. In the case of marine stingrays, the injuries made by their tail venom apparatus are caused by the mechanical penetration of their sting and a subsequent venom release. This study focused on the evaluation of substances with cytotoxic activity in the epithelium that covers the venom apparatus from the marine stingray Hypanus dipterurus. To demonstrate the above, the hemolytic, proteolytic and cytotoxic capacities of H. dipterurus epithelium substances were determined. Discs impregnated with epithelial extract were used on blood agar plates. The proteolytic activity was analyzed using casein as substrate and for gelatin the liquefaction activity test. To determine the cytotoxicity degree of the extracts, the proliferation and cell viability MTT bioassay was implemented on human cervical carcinoma cells (HeLa). The results showed that no hemolytic or proteolytic activity existed against casein associated with the epithelial extract, but gelatin hydrolysis and cytotoxic activity against the HeLa cell line were observed. This study concludes that the substances found in the epithelium covering the H. dipterurus stingray venom apparatus are a mixture of various proteins, among which, glycosylated anionic proteins represent a potential source of molecules with cytotoxic and hydrolytic activity.

Scorpion venoms and associated toxins as anticancer agents: update on their application and mechanism of action

Cancer remains one of the deadliest non-infectious diseases of the 21^st century, causing millions of mortalities per year worldwide. Analyses of conventional treatments, such as radiotherapy and chemotherapy, have shown not only a lower therapeutic efficiency rate but also plethora of side-effects. Considering the desperate need to identify promising anticancer agents, researchers are in quest to design and develop new tumoricidal drugs from natural sources. Over the past few years, scorpion venoms have shown exemplary roles as pivotal anticancer agents. Scorpion venoms associated metabolites, particularly toxins demonstrated in vitro anticancer attributes against diversified cell lines by inhibiting the growth and progression of the cell cycle, inhibiting metastasis by blocking ion channels such as K⁺ and Cl^- , and/or inducing apoptosis by intrinsic and extrinsic pathways. This review sheds light not only on in vitro anticancer properties of distinct scorpion venoms and their toxins, but also on their mechanism of action for designing and developing new therapeutic drugs in future.

Tityus serrulatus Scorpion Venom Induces Apoptosis in Cervical Cancer Cell Lines

Cervical cancer (CC) is classified as the fourth most common type of cancer in women worldwide and remains a serious public health problem in many underdeveloped countries. Human papillomavirus (HPV), mainly types 16 and 18, has been established as a precursory etiologic agent for this type of cancer. Several therapeutic attempts have been studied and applied, aiming at its control. However, not only do classical treatments such as chemotherapies and radiotherapies target tumor cells, but also they cause damage to several healthy cells. For these reasons, the search for new biologically active chemotherapeutic components is of great importance. In this study, we investigated the effect of Tityus serrulatus scorpion venom (TsV) on CC lines. There are very few studies exploring venom of scorpions, and, to our knowledge, no study has been conducted using the venom of the scorpion TsV for treatment of cervical cancer lines. After challenge with TsV, the MTT assay demonstrated cytotoxic effect on HeLa line. Similarly, the cell death process in HeLa analyzed by flow cytometry suggests death via caspase, since the pan-caspase inhibitor z-VAD-fmk significantly reduced the apoptotic response to the treatment. These results suggest that venom of TsV can be a potential source for the isolation of effective antiproliferative and apoptotic molecules in the treatment of CC.

Cytotoxic and Anticancer Effects of ICD-85 (Venom Derived Peptides) in Human Breast Adenocarcinoma and Normal Human Dermal Fibroblasts

ICD-85 (venom derived peptides) has anti-proliferative effect and anti- angiogenesis activity on cancer cells. This study was performed to test the effect of ICD-85, on Human breast adenocarcinoma (MCF-7) and normal Human Dermal Fibroblasts (HDF) cell lines. In this experimental study, Mitochondrial activity, Neutral red uptake, Lactate dehydrogenase (cell necrosis), and cell morphology were assessed under unexposed and ICD-85 exposed conditions. Caspase-9 colorimetric assay kit was used to determine caspase protease activity. Morphological changes in MCF-7 cells on treatment with ICD-85 compared with untreated MCF-7 cells are consistent with characterizing the features of apoptosis such as granulation and cell rounding which finally results in the generation of apoptotic bodies. In contrast, this difference was not observed in normal cells. In MTT assay, ICD-85 induced dose dependent manner cytotoxic effects on MCF-7 cells which were confirmed by neutral red assay. The results showed that inhibitory concentration 50% (IC50) value of ICD-85 for MCF-7 cells at 24 h was 36.45 ± 0.38 μg/mL. However, when HDF cells were exposed to ICD-85, no significant elevation of LDH release were observed at concentrations below 20 μg/mL. The apoptosis-induction of ICD-85 on MCF-7 cell was found to be through activation of caspase-9 which was 13 fold greater than unexposed cell. This study showed that ICD-85 induced apoptosis in MCF-7 cell line through caspase activation and hence it can be considered for further investigation to use ICD-85 as a potential therapy for breast cancer.

Cytotoxic and apoptotic activities of black widow spiderling extract against HeLa cells

Black widow spiders contain toxic components not only in the venom glands but also in other parts of the spider body, including the legs and abdomen. Additionally, both the eggs and newborn spiderlings of the black widow spider contain venom. It is important to investigate their potential effects on cancer cells. In the present study, the effects of newborn black widow spiderling extract on human HeLa cells were evaluated in vitro. When applied at different concentrations, the total extract decreased HeLa cell viability in a dose-dependent manner, with an IC₅₀ value of 158 µg/ml. Flow cytometry indicated that treatment of HeLa cells with the total extract of the spiderlings induced apoptosis in HeLa cells in a dose-dependent manner and led to cell cycle arrest in the S-phase. Additionally, application of the total extract at different concentrations increased apoptosis-related caspase 3 activity in a dose-dependent manner. HeLa cells treated with the total extract appeared to be morphologically changed, exhibiting membrane blebbing, nuclear fragmentation and condensation of chromatin. Further separation and activity screening demonstrated that the cytotoxic and apoptotic activities of the total extract were attributable mainly to its high molecular mass proteins, one of which was purified and characterized to determine its anti-tumor activities on HeLa cells. The results of the present study therefore have expanded understanding regarding the effect of spider toxins on cancer cells and suggested that components of black widow spiderlings may be developed as a promising novel agent to treat cancer.

Cytotoxic activity of Androctonus australis hector venom and its toxic fractions on human lung cancer cell line

Background

Several studies have showed that animal venoms are a source of bioactive compounds that may inhibit the growth of cancer cells, which makes them useful agents for therapeutic applications. Recently, it was established that venom toxins from scorpions induced cytotoxic, antiproliferative and apoptogenic effects on cancer cells. Therefore, the present study aims to investigate the cytotoxic activity of Androctonus australis hector (Aah) scorpion venom and its toxic fractions (FtoxG-50 and F3) on NCI-H358 human lung cancer cells.

Methods

The cytotoxic and antiproliferative activities were estimated using MTT assay, lactate dehydrogenase release and clonogenic assays. Apoptosis was evaluated by Hoechst 33258 staining, DNA fragmentation assay and caspase-3 activity. Oxidative stress was analyzed by reactive oxygen species, nitric oxide, malondialdehyde and protein carbonyl levels along with assessment of antioxidant status. In addition, alteration of mitochondrial membrane potential was analyzed by JC1 fluorescent dye.

Results

The present findings showed that F3 fraction was more cytotoxic towards NCI-H358 lung cancer cells with an IC₅₀ of 27.05 ± 0.70 μg/mL than venom alone (396.60 ± 1.33 μg/mL) and its toxic fraction FtoxG-50 (45.86 ± 0.91 μg/mL). Nevertheless, F3 fraction was not cytotoxic at these concentrations on normal human lung fibroblast MRC-5 cells. Inhibition of NCI-H358 cell proliferation after F3 fraction exposure occurred mainly by apoptosis as evidenced by damaged nuclei, significant DNA fragmentation level and caspase-3 activation in a dose dependent manner. Moreover, F3 fraction enhanced oxidative and nitrosative stress biomarkers and dissipated mitochondrial membrane potential in lung cancer cells along with significant depletion in cellular enzymatic and non-enzymatic antioxidants. Further, the apoptosis induced by F3 fraction was markedly prevented by the antioxidant N-acetylcysteine (NAC) suggesting the potential mechanism of oxidative stress.

Conclusion

These findings suggest that F3 fraction could induce apoptosis in lung cancer cells through involvement of oxidative stress and mitochondrial dysfunction. Hence, these properties make F3 fraction a promising candidate for development of new anticancer agents.