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

l-Securinine Induces ROS-Dependent Apoptosis on Pancreatic Cancer Cells via the PI3K/AKT/mTOR Signaling Pathway

Accumulating evidence has shown that l-securinine can, in certain circumstances, suppress tumor development by elevating reactive oxygen species (ROS) levels. The current work set out to examine l-securinine's apoptotic effects on HuP-T3 cells as well as any potential underlying molecular mechanism(s) that could explain its action as an anticancer agent. In this study, we used 1.2B4 cells as a control human cell line to verify our findings. Hup-T3 and 1.2B4 cells were cultured with a medium containing the following dilutions of l-securinine: 1-10 μΜ for up to 72 h. We examined the viability and proliferation levels of cells in both cell lines. Then, we measured only 1.2B4 insulin levels and content. We also quantified cell apoptosis, cell cycle levels, and the intracellular reactive oxygen species on HuP-T3 and 1.2B4. Afterwards, we performed a real-time quantitative polymerase chain reaction and western blot analysis. Our results demonstrated that l-securinine inhibited both proliferation and growth of Hup-T3 cells, showing inhibitory and antiproliferative activity in comparison with the control group. In addition, l-securinine had no impact on the proliferation and growth of 1.2B4 cells, nor on their insulin levels and content. By boosting ROS production, and inhibiting the PI3K/AKT/mTOR signaling pathway, l-securinine induced apoptosis on HuP-T3 cells. Pancreatic cancer was successfully inhibited by l-securinine in vitro. l-securinine triggers ROS-dependent apoptosis on pancreatic cancer cells while inhibiting the PI3K/AKT/mTOR signaling pathway. These findings suggest that l-securinine holds promise as a potential lead for future drug development in the fight against pancreatic adenocarcinoma.

Interaction of Norsecurinine-Type Oligomeric Alkaloids with α-Tubulin: A Molecular Docking Study

The medicinal plant Securinega virosa (Roxb ex. Willd) Baill., also known as Flueggea virosa (Roxb. ex Willd.) Royle, is commonly used in traditional medicine in Africa and Asia for the management of diverse pathologies, such as parasite infections, diabetes, and gastrointestinal diseases. Numerous alkaloids have been isolated from the twigs and leaves of the plant, notably a variety of oligomeric indolizidine alkaloids derived from the monomers securinine and norsecurinine which both display anticancer properties. The recent discovery that securinine can bind to tubulin and inhibit microtubule assembly prompted us to investigate the potential binding of two series of alkaloids, fluevirosines A-H and fluevirosinine A-J, with the tubulin dimer by means of molecular modeling. These natural products are rare high-order alkaloids with tri-, tetra-, and pentameric norsecurinine motifs. Despite their large size (up to 2500 Å3), these alkaloids can bind easily to the large drug-binding cavity (about 4800 Å3) on α-tubulin facing the β-tubulin unit. The molecular docking analysis suggests that these hydrophobic macro-alkaloids can form stable complexes with α/β-tubulin. The tubulin-binding capacity varies depending on the alkaloid size and structure. Structure-binding relationships are discussed. The docking analysis identifies the trimer fluevirosine D, tetramer fluevirosinine D, and pentamer fluevirosinine H as the most interesting tubulin ligands in the series. This study is the first to propose a molecular target for these atypical oligomeric Securinega alkaloids.

Securinine inhibits the tumor growth of human bladder cancer cells by suppressing Wnt/β-catenin signaling pathway and activating p38 and JNK signaling pathways

Bladder cancer (BC) is the most common malignant tumor in urinary system. Although chemotherapy is one of the most important adjuvant treatments for BC, drug resistance, non-specific toxicity and severe side effects are the major obstacles to BC chemotherapy. Natural products have always been a leading resource of antitumor drug discovery, with the advantages of excellent effectiveness, low toxicity, multi-targeting potency and easy availability. In this study, we evaluated the potential anti-tumor effect of securinine (SEC), a natural alkaloid from Securinega suffruticosa, on BC cells in vitro and in vivo, and delineated the underlying mechanism. We found that SEC inhibited the proliferation, migration and invasion, induced the apoptosis of BC cells in vitro, and retarded the xenograft tumor growth of BC cell in vivo. Notably, SEC had a promising safety profile because it presented no or low toxicity on normal cells and mice. Mechanistically, SEC inactivated Wnt/β-catenin signaling pathway while activated p38 and JNK signaling pathway. Moreover, β-catenin overexpression, the p38 inhibitor SB203580 and the JNK inhibitor SP600125 both mitigated the inhibitory effect of SEC on BC cells. Furthermore, we demonstrated a synergistic inhibitory effect of SEC and gemcitabine (GEM) on BC cells in vitro and in vivo. Taken together, our findings suggest that SEC may exert anti-BC cell effect at least through the activation of p38 and JNK signaling pathways, and the inhibition of Wnt/β-catenin signaling pathway. More meaningfully, the findings indicate that GEM-induced BC cell killing can be enhanced by combining with SEC.

Bioactivities and mechanism of action of securinega alkaloids derivatives reported prior to 2022

Securinega alkaloids are indolizidine alkaloids extracted from the leaf and root of an Asian plant, Securinega suffruticosa. Since its discovery in 1956 by Russian scientists, numerous studies have been conducted on securinega alkaloids and their derivatives as bioactive agents. In this review, published work on the bioactivities and the mechanism of action of securinega alkaloids and their derivatives is addressed. References were obtained through for example, the Web of Science, Science Direct, Pubmed and Google Scholar. Research into the synthesis of securinega alkaloids and their derivatives lacking activity assessment has been excluded. Comprehensive reviews show that securinega alkaloids and their derivatives exhibit a wide range of activities among which antineoplastic activity and nervous system related activity were reported although the mechanisms of action remain in part unknown. The other activities such as induction of differentiation, reversal of multi-drug resistance, cardiovascular system related activity, anti-inflammatory, adjuvant agent and anti-pathogenic activity are also reviewed. We found that modification at the C12, C14, and C15 sites on securinine improves the antitumor activity, while derivatives in which a bivalent mimetic is linked to the C15 site is beneficial for differentiation induction activity and reversal of P-glycoprotein mediated drug resistance. The most related pathways involved in the bioactivity of securinega alkaloids and their derivatives are JAK/STAT, PI3K/AKT/mTOR and MAPK. A perspective and expectation concerning the research of securinega alkaloids is presented at the end of this article. This review indicates directions around which constant endeavor could be valuable for researchers in the near future.

Antibacterial and Antifungal Alkaloids from Asian Angiosperms: Distribution, Mechanisms of Action, Structure-Activity, and Clinical Potentials

The emergence of multidrug-resistant bacteria and fungi requires the development of antibiotics and antifungal agents. This review identified natural products isolated from Asian angiosperms with antibacterial and/or antifungal activities and analyzed their distribution, molecular weights, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and a library search from 1979 to 2022. One hundred and forty-one antibacterial and/or antifungal alkaloids were identified during this period, mainly from basal angiosperms. The most active alkaloids are mainly planar, amphiphilic, with a molecular mass between 200 and 400 g/mol, and a polar surface area of about 50 Å2, and target DNA and/or topoisomerase as well as the cytoplasmic membrane. 8-Acetylnorchelerythrine, cryptolepine, 8-hydroxydihydrochelerythrine, 6-methoxydihydrosanguinarine, 2'-nortiliacorinine, pendulamine A and B, rhetsisine, sampangine, tiliacorine, tryptanthrin, tylophorinine, vallesamine, and viroallosecurinine yielded MIC ≤ 1 µg/mL and are candidates for the development of lead molecules.

SLC7A11, a Potential Therapeutic Target Through Induced Ferroptosis in Colon Adenocarcinoma

Background: Ferroptosis induced by SLC7A11 has an important translational value in the treatment of cancers. However, the mechanism of SLC7A11 in the pathogenesis of colon adenocarcinoma (COAD) is rarely studied in detail.

Methods: SLC7A11 expression was explored with The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) databases, and Western blot assay. The correlation of SLC7A11 expression with the abundance of infiltrating immune cells was evaluated via the TIMER database. The relation of SLC7A11 expression with immune cell markers was investigated via Gene Expression Profiling Interactive Analysis (GEPIA). The co-expression genes of SLC7A11 were screened by R packages, and the PPI was constructed via the STRING database. SLC7A11 and co-expressed gene modulators were selected by NetworkAnalyst and DSigDB database. The correlations between SLC7A11 and cancer immune characteristics were analyzed via the TIMER and TISIDB databases.

Results: SLC7A11 is overexpressed in most tumors, including COAD. The expression level of SLC7A11 has a significant correlation with the infiltration levels of CD8⁺ T cells, neutrophils, and dendritic cells in COAD. The infiltrated lymphocyte markers of Th1 cell such as TBX21, IL12RB2, IL27RA, STAT1, and IFN-γ were strongly correlated with SLC7A11 expression. Five hub genes co-expressed with SLC7A11 that induce ferroptosis were identified, and mir-335-5p, RELA, and securinine have regulatory effects on it. SLC7A11 was negatively correlated with the expression of chemokines and chemokine receptors, such as CCL17, CCL19, CCL22, CCL23, CXCL14, CCR10, CX3CR1, and CXCR3, in COAD.

Conclusion: SLC7A11 may play a role in induced ferroptosis and regulating tumor immunity, which can be considered as potential therapeutic targets in COAD.