Plumbagin inhibits the proliferation of nasopharyngeal carcinoma 6-10B cells by upregulation of reactive oxygen species

In silico analysis and experimental validation to exhibit anti-nasopharyngeal carcinoma effects of plumbagin, an anti-cancer compound

BACKGROUND

Nasopharyngeal carcinoma (NPC) is publicly known as a malignant tumor. Our previous study reported that plumbagin exhibits potent anti-cancer actions. Nevertheless, more mechanical details of plumbagin against NPC remain unknown. The present study aimed to unmask the core targets/genes and anti-NPC mechanisms involved in the signaling pathways of plumbagin prior to biochemical validation.

METHODS

A network pharmacology approach was employed to respective identification of mutual and core targets/genes in plumbagin and/treating NPC. Molecular docking determination was used to identify core target proteins for biochemical validation using human and cell line samples.

RESULTS

In total, 60 anti-NPC genes of plumbagin were screened out, and then nine core target genes of plumbagin against NPC were identified accordingly. The enrichment findings revealed detailed biological functions and pharmacological pathways of plumbagin against NPC. Moreover, in silico analysis using molecular docking had determined the core targets for further experimental validation, comprising protein kinase B (AKT1) and sarcoma gene (SRC). In human sample validation, clinical NPC sections showed increased positive expression of AKT1 and SRC. Additionally, plumbagin-treated NPC cells resulted in inactivated protein expression of AKT1 and SRC.

CONCLUSION

The re-identified core targets/genes in the molecular docking report may function as plumbagin-related pharmacological targets for treating NPC via experimental validation. Furthermore, additional anti-NPC molecular mechanisms of plumbagin action were disclosed on the basis of enrichment findings. © 2022 Society of Chemical Industry.

Pentagalloylglucose suppresses the growth and migration of human nasopharyngeal cancer cells via the GSK3β/β-catenin pathway in vitro and in vivo

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a type of malignant squamous cell tumour originating from the nasopharynx epithelium. Pentagalloylglucose (PGG) is a natural polyphenolic compound that exerts anticancer effects in many types of tumours. However, the role and underlying mechanism of PGG in NPC cells have not been fully defined.

PURPOSE

This study aimed to investigate the anticancer activity of PGG as well as the potential mechanism in NPC cells.

METHODS

The effects of PGG on the proliferation, apoptosis and cell cycle distribution of CNE1 and CNE2 cells were assessed by MTT and flow cytometry assays. Cell migration was evaluated using wound healing and transwell assays. The expression of microtubule-associated protein 1 light chain 3 beta (LC3B) was observed by immunofluorescence staining. Western blotting was used to explore the levels of related proteins and signalling pathway components. Furthermore, the effects of PGG on NPC cell growth were analysed in a xenograft mouse model in vivo using cisplatin as a positive control.

RESULTS

PGG dose-dependently inhibited the proliferation of CNE1 and CNE2 cells. PGG regulated the cell cycle by altering p53, cyclin D1, CDK2, and cyclin E1 protein levels. PGG induced apoptosis and autophagy in NPC cells and elevated the Bax/Bcl-2 ratio and the protein levels of LC3B. Moreover, PGG decreased NPC cell migration by increasing E-cadherin and decreasing N-cadherin, vimentin and CD44 protein levels. Mechanistically, PGG treatment downregulated p-mTOR and β-catenin expression but upregulated p-p38 MAPK and p-GSK3β expression. In addition, PGG significantly inhibited NPC cell tumour growth and lung metastasis in vivo.

CONCLUSION

PGG may suppress cell proliferation, induce apoptosis and autophagy, and decrease the metastatic capacity of NPC cells through the p38 MAPK/mTOR and Wnt/β-catenin pathways. The present study provides evidence for PGG as a potential therapy for NPC.

Establishment of a Jaw Fibrosarcoma Patient-Derived Xenograft and Evaluation of the Tumor Suppression Efficacy of Plumbagin Against Jaw Fibrosarcoma

Background: Head and neck fibrosarcoma is a rare malignant tumor, accounting for about 1% of all head and neck tumors. It can also occur in the jaw bone, for which surgical resection is the main treatment but the recurrence rate is high and the prognosis is usually poor. Due to the lack of models mimicking the biological characteristics of the tumor, there is little progress in the research of the pathogenesis and treatment of fibrosarcoma. Therefore, there is an urgent need to explore a high-fidelity model that can reflect the biological characteristics of fibrosarcoma for the sake of improving the therapeutic outcome and prognosis, and preventing recurrence. Patient-derived xenografts (PDX) may more accurately reflect the human disease, and is an attractive platform to study disease biology and develop treatments and biomarkers. In this study we describe the establishment of jaw fibrosarcoma PDX models and compare PDX tumors to those of human origin.

Methods: Tumor biopsies from a patient with jaw fibrosarcoma were implanted in immunodeficient mice. Primary and PDX tumors were characterized extensively by histology, immunohistochemistry and humanized identification. Based on the finding of our previous preliminary research that plumbagin had an anti-tumor effect against head and neck cancer, we used this model in the present study to evaluate the anti-tumor effect of plumbagin on jaw fibrosarcoma.

Results: The established PDX model maintained the histological and immunohistochemical characteristics of the primary tumor. Plumbagin significantly inhibited the tumor growth in the jaw fibrosarcoma PDX model.

Conclusion: We successfully established a PDX model of jaw fibrosarcoma and demonstrated that this PDX model preserved the important molecular characteristics of the human primary tumor, thus providing a powerful tool for treatment research and new drug development of jaw fibrosarcoma. In addition, plumbagin was found to have an inhibitory effect on the growth of PDX modeled jaw fibrosarcoma, which provides a preliminary research basis for its clinical application.

Comparison of the Effect of Native 1,4-Naphthoquinones Plumbagin, Menadione, and Lawsone on Viability, Redox Status, and Mitochondrial Functions of C6 Glioblastoma Cells

Background: 1,4-naphthoquinones, especially juglone, are known for their anticancer activity. However, plumbagin, lawsone, and menadione have been less investigated for these properties. Therefore, we aimed to determine the effects of plumbagin, lawsone, and menadione on C6 glioblastoma cell viability, ROS production, and mitochondrial function. Methods: Cell viability was assessed spectrophotometrically using metabolic activity method, and by fluorescent Hoechst/propidium iodide nuclear staining. ROS generation was measured fluorometrically using DCFH-DA. Oxygen uptake rates were recorded by the high-resolution respirometer Oxygraph-2k. Results: Plumbagin and menadione displayed highly cytotoxic activity on C6 cells (IC₅₀ is 7.7 ± 0.28 μM and 9.6 ± 0.75 μM, respectively) and caused cell death by necrosis. Additionally, they increased the amount of intracellular ROS in a concentration-dependent manner. Moreover, even at very small concentrations (1–3 µM), these compounds significantly uncoupled mitochondrial oxidation from phosphorylation impairing energy production in cells. Lawsone had significantly lower viability decreasing and mitochondria-uncoupling effect, and exerted strong antioxidant activity. Conclusions: Plumbagin and menadione exhibit strong prooxidant, mitochondrial oxidative phosphorylation uncoupling and cytotoxic activity. In contrast, lawsone demonstrates a moderate effect on C6 cell viability and mitochondrial functions, and possesses strong antioxidant properties.