Securinine induces mitotic block in cancer cells by binding to tubulin and inhibiting microtubule assembly: A possible mechanistic basis for its anticancer activity.

AIM: Analysis of the anticancer and antimitotic activity of the plant derived alkaloid securinine along with its effect on the organization of cellular microtubules as well as its binding with purified goat brain tubulin in-vitro. MATERIALS AND METHODS: The cytotoxicity of securinine on different cell lines was conducted using SRB assay. The effect of securinine on the cellular microtubules was analyzed using immunofluorescence microscopy. The binding of securinine on purified goat brain tubulin was evaluated using fluorescent spectroscopy. KEY FINDINGS: Securinine effectively prevented the proliferation of cervical, breast and lung cancer cells with an IC50 of 6, 10 and 11 µM respectively and induced minimal toxicity in HEK cell line. Securinine at concentrations higher than IC50 induced significant depolymerization in interphase and mitotic microtubules and it suppressed the reassembly of cold depolymerized spindle microtubules in HeLa cells. In the wound healing assay, securinine effectively suppressed the migration of HeLa cells to close the wound. Securinine bound to tubulin with a Kd of 9.7 µM and inhibited the assembly of tubulin into microtubules. The treatment with securinine induced a mitochondrial dependent ROS response in HeLa cells which enhanced the cytotoxic effect of securinine. The result from gene expression studies indicates that securinine induced apoptosis in MCF-7 cells through p53 dependent pathway. SIGNIFICANCE: Considering the strong anticancer and anti-metastatic property and low toxicity in non-malignant cell lines, we suggest that securinine can be used as a chemotherapeutic drug either alone or in combination with other known anticancer molecules.

Securinine suppresses osteoclastogenesis and ameliorates inflammatory bone loss.

Securinine (Sec) is a naturally derived compound separated from the roots of Securinega suffruticosa, which has long been used as a herbal medicine. Sec is widely known as a GABA receptor antagonist, it is also known as an innate immune cell agonist and has been reported to increase macrophage activity and promote monocyte maturation. On the basis of these studies, we investigated the effect of Sec on osteoclast differentiation and bone resorbing function. We have found that Sec inhibits RANKL-induced osteoclast differentiation, fusion, actin ring formation, and bone resorbing function by the inhibition of gene expression associated with each stage. Moreover, Sec significantly suppressed osteoclastogenesis by decreasing the phosphorylation of p38, Akt, JNK, IκB, and PLCγ2, in pathways involved in early osteoclastogenesis as well as through the subsequent suppression of c-Fos and NFATc1. Finally, Sec effectively protected bone loss induced by the excessive inflammatory responses and activity of osteoclasts in vivo by a micro-CT and histological analysis. In conclusion, our findings suggest that Sec may be a promising drug for bone metabolic diseases such as osteoporosis, which is associated with the excessive activity of osteoclasts.

Levistilide A Ameliorates NLRP3 Expression Involving the Syk-p38/JNK Pathway and Peripheral Obliterans in Rats.

BACKGROUND: Inflammation is one of the most important pathogeneses of thromboangiitis obliterans (TAO). The NLRP3 inflammasome plays a vital role in the body's immune response and disease development. It can be activated by numerous types of pathogens or danger signals. As the core of the inflammatory response, the NLRP3 inflammasome may provide a new target for the treatment of various inflammatory diseases. Levistilide A (LA) is a phthalide dimer isolated from umbelliferous plants. Its pharmacological effect is largely unknown. This study revealed the effects of LA on endothelial cell activation, NLRP3, IL-1ß, TNF-α, IL-32, and CCL-2, VCAM-1, MCP-1, and the spleen tyrosine kinase (Syk)--p38/JNK signaling axis and its effect on vasculitis in rats. RESULTS: LA inhibited endothelial activation and the expression of IL-1ß, TNF-α, IL-32, CCL-2, VCAM-1, and MCP-1. LA directly obstructed Syk phosphorylation and activity in a dose-dependent manner, inhibited the activity of p38 and JNK, and reduced the expression of NLRP3 in human umbilical vein endothelial cells and vascular tissue of rats with vasculitis. CONCLUSION: LA suppressed NLRP3 gene expression by blocking the Syk--p38/JNK pathway and reduced damage to the rats' limbs in the thromboangiitis obliterans model.

A combination of astragaloside I, levistilide A and calycosin exerts anti-liver fibrosis effects in vitro and in vivo.

Liver fibrosis is excessive accumulation of extracellular matrix proteins that results from various chronic liver diseases. Hepatic stellate cells (HSCs) play an essential role in the pathogenesis of liver fibrosis. Danggui Buxue Tang (DBT) is a classic formula of Chinese traditional medicine. We previously showed that DBT could ameliorate liver fibrosis in rats. However, the bioactive components of DBT in the treatment of liver fibrosis remain unknown. In this study we evaluated 14 ingredients from DBT in human hepatic stellate cell line LX-2, and found that astragaloside I (A), levistilide A (L) and calycosin (C) produced synergistic proliferation inhibition on LX-2 cells and TGF-ß1-activated LX-2 cells. Thus, we prepared a mixture of them, and named this combination as ALC formula. Using high-content screening and Western blot assay we revealed that the ALC formula significantly reduced the expression of α-SMA and collagen I in LX-2 cells. The in vivo anti-fibrosis effects of ALC formula were evaluated in a liver fibrosis model in C57BL/6 mice established through injection of dimethylnitrosamine (DMN 2 mg/kg, ip) for 4 weeks. In the third week, the nice were injected with ALC formula (astragaloside I 44.21 mg/kg per day, levistilide A 6 mg/kg per day and calycosin 3.45 mg/kg per day; ip) or sorafenib, a positive control drug (6 mg/kg per day, ip) for 2 weeks. We found that administration of the ALC formula markedly decreased collagen deposition, hydroxyproline (Hyp) content and α-SMA expression levels in the liver tissues compared to the model mice. In conclusion, the present study demonstrates for the first time that astragaloside I, levistilide A and calycosin may be the 3 main bioactive components in DBT; their combination exerts anti-liver fibrosis effects in vitro and in vivo.

Anti-Inflammatory and Neuroprotective Role of Natural Product Securinine in Activated Glial Cells: Implications for Parkinson's Disease.

Glial activation and subsequent release of neurotoxic proinflammatory factors are believed to play an important role in the pathogenesis of several neurological disorders including Parkinson's disease (PD). Inhibition of glial activation and inflammatory processes may represent a therapeutic target to alleviate neurodegeneration. Securinine, a major natural alkaloid product from the root of the plant Securinega suffruticosa, has been reported to have potent biological activity and is used in the treatment of neurological conditions such as amyotrophic lateral sclerosis, poliomyelitis, and multiple sclerosis. In this study, we explored the underlying mechanisms of neuroprotection elicited by securinine, particularly its anti-inflammatory effects in glial cells. Our results demonstrate that securinine significantly and dose-dependently suppressed the nitric oxide production in microglia and astrocytic cultures. In addition, securinine inhibited the activation of the inflammatory mediator NF-κB, as well as mitogen-activated protein kinases in lipopolysaccharide- (LPS-) stimulated BV2 cells. Additionally, securinine also inhibited interferon-γ- (IFN-γ-) induced nitric oxide levels and iNOS mRNA expression. Furthermore, conditioned media (CM) from securinine pretreated BV2 cells significantly reduced mesencephalic dopaminergic neurotoxicity compared with CM from LPS stimulated microglia. These findings suggest that securinine may be a potential candidate for the treatment of neurodegenerative diseases related to neuroinflammation.

Securinine Derivatives as Potential Anti-amyloid Therapeutic Approach.

BACKGROUND: Oxidative stress and amyloid deposition are tightly interconnected pathological features of Alzheimer disease. In this respect, both amyloid production and aggregation may be stimulated by oxidative stress and also the increase of pathogenic ß-amyloid and its aggregated form lead to oxidative stress progression. Therefore, the search for potential drugs with both antioxidant and antiaggregation properties are of great interest. METHODS: In this study, we described the stereospecific synthesis of alkaloid securinine aminoderivatives. RESULTS: We showed that the newly synthesized compounds possess antioxidant and metal-chelating properties. Indeed, we report that one compound has inhibitory effects towards µ-amyloid aggregation. CONCLUSION: Based on these results, aminoderivatives of securinine scaffold are promising compounds for development of new drugs for the treatment of neurodegenerative diseases.