Cytotoxicity mechanisms of plumbagin in drug-resistant tongue squamous cell carcinoma

Enhancing sensitivity to oxaliplatin in tongue squamous cell carcinoma: mechanistic insights and therapeutic potential of DHA combination therapy

Squamous cell carcinoma of the tongue, a common and aggressive malignancy, poses a substantial threat to health and well-being. Despite the promising results of combination therapy with dihydroartemisinin (DHA) and oxaliplatin (Oxa) in various cancers, its effectiveness in treating tongue squamous cell carcinoma had not been explored prior to this study. Our research found that DHA significantly enhances the sensitivity of tongue squamous cell carcinoma cells to Oxa, even at very low concentrations. The combination treatment was observed to modulate the activity of CDK1 and Cyclin B1, arresting the cell cycle in the G2 phase. Additionally, it reduces mitochondrial membrane potential, prompting the release of cytochrome c and activating cleaved caspase-3, which promotes apoptosis. Notably, surface plasmon resonance and immunoprecipitation experiments revealed that DHA targets and attenuates CDK1 modification, weakening its interaction with STAT3 protein. This leads to reduced expression of anti-apoptotic genes and facilitates programmed cell death in CAL-27 cells. The findings underscore the potential of DHA and Oxa as a potent therapeutic strategy for tongue squamous cell carcinoma, opening avenues for clinical application and further exploration into its mechanistic pathways.

Pharmacological Features and Therapeutic Implications of Plumbagin in Cancer and Metabolic Disorders: A Narrative Review

Plumbagin (PLB) is a naphthoquinone extracted from Plumbago indica. In recent times, there has been a growing body of evidence suggesting the potential importance of naphthoquinones, both natural and artificial, in the pharmacological world. Numerous studies have indicated that PLB plays a vital role in combating cancers and other disorders. There is substantial evidence indicating that PLB may have a significant role in the treatment of breast cancer, brain tumours, lung cancer, hepatocellular carcinoma, and other conditions. Moreover, its potent anti-oxidant and anti-inflammatory properties offer promising avenues for the treatment of neurodegenerative and cardiovascular diseases. A number of studies have identified various pathways that may be responsible for the therapeutic efficacy of PLB. These include cell cycle regulation, apoptotic pathways, ROS induction pathways, inflammatory pathways, and signal transduction pathways such as PI3K/AKT/mTOR, STAT3/PLK1/AKT, and others. This review aims to provide a comprehensive analysis of the diverse pharmacological roles of PLB, examining the mechanisms through which it operates and exploring its potential applications in various medical conditions. In addition, we have conducted a review of the various formulations that have been reported in the literature with the objective of enhancing the efficacy of the compound. However, the majority of the reviewed data are based on in vitro and in vivo studies. To gain a comprehensive understanding of the safety and efficacy of PLB in humans and to ascertain its potential integration into therapeutic regimens for cancer and chronic diseases, rigorous clinical trials are essential. Finally, by synthesizing current research and identifying gaps in knowledge, this review seeks to enhance our understanding of PLB and its therapeutic prospects, paving the way for future studies and clinical applications.

Anti-inflammatory and analgesic effects of Streblus indicus

The bark of Streblus indicus, a Dai medicine in China, has been listed in the Chinese Materia Medica as possessing hemostatic and analgesic properties. Ethnic medicine books record that its bark or leaves for the treatment of mumps and lymphoma. However, according to the literature survey, anti-inflammatory and analgesic studies available for leaves and branches of S. indicus have been seldom reported so far. The current study focuses on the metabolites of S. indicus bark and leaves responsible for anti-inflammatory and analgesic effects on the basis of bioactive-included acetic acid writhing, hot-plate, and xylene-induced ear swelling. The secretion of inflammatory mediators, TNF-α, IL-6, IL-1β, IL-4, and IL-10, were evaluated for their anti-inflammatory by xylene-induced in mouse ear cells. Histological examination was used to assess the anti-inflammatory and analgesic effects of the branches and leaves of S. indicus, and Western blot analysis determined the mechanism of the methanolic extract of branches and leaves. Different metabolites of S. indicus significantly alleviated analgesic and anti-inflammatory effects, with no discernable differences among them. All metabolites decreased the levels of TNF-α, IL-1β, and IL-6 and increased the levels of IL-4 and IL-10. The analgesic and anti-inflammatory mechanism of the methanolic extract was related to the NF-kB signaling pathway. These results not only would account for scientific knowledge for the traditional application of S. indicus, but also provide a credible theoretical foundation for the further development of anti-inflammatory and analgesic agents.

Plumbagin induces the apoptosis of drug-resistant oral cancer in vitro and in vivo through ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction

BACKGROUND

Oral cancer is one of the leading causes of cancer-related deaths worldwide. Chemotherapy is widely used in the treatment of oral cancer, but its clinical efficacy is limited by drug resistance. Hence, novel compounds capable of overcoming drug-resistance are urgently needed.

PURPOSE

Plumbagin (PG), a natural compound isolated from Plumbago zeylanica L, has been used to treat various cancers. In this study, we investigated the anticancer effects of PG on drug-resistant oral cancer (CR-SAS) cells, as well as the underlying mechanism.

METHODS

MTT assays were used to evaluate the effect of PG on the viability of CR-SAS cells. Apoptosis and reactive oxygen species (ROS) production by the cells were determined using flow cytometry. Protein expression levels were detected by western blotting.

RESULTS

The results show that PG reduces the viability and causes the apoptosis of CR-SAS cells. PG is able to induce intracellular and mitochondrial ROS generation that leads to mitochondrial dysfunction. Furthermore, endoplasmic reticulum (ER) stress was triggered in PG-treated CR-SAS cells. The inhibition of ROS using N-acetylcysteine (NAC) abrogated the PG-induced ER stress and apoptosis, as well as the reduction in cell viability. Meanwhile, similar results were observed both in zebrafish and in murine models of drug-resistant oral cancer.

CONCLUSION

Our results indicate that PG induces the apoptosis of CR-SAS cells via the ROS-mediated ER stress pathway and mitochondrial dysfunction. It will be interesting to develop the natural compound PG for the treatment of drug-resistant oral cancer.

4,7-Didehydro-neophysalin B Protects Rat Lung Epithelial Cells against Hydrogen Peroxide-Induced Oxidative Damage through Nrf2-Mediated Signaling Pathway

The administration of 4,7-didehydro-neophysalin B is expected to be a promising strategy for mitigating oxidative stress in respiratory diseases. This study was aimed at investigating the efficacy of 4,7-didehydro-neophysalin B for apoptosis resistance of rat lung epithelial cells (RLE-6TN) to oxidative stress and evaluating its underlying mechanism of action. The RLE-6TN cells treated with hydrogen peroxide (H₂O₂) were divided into five groups, and 4,7-didehydro-neophysalin B was administered into it. To evaluate its mechanism of action, the expression of oxidative stress and apoptotic proteins was investigated. 4,7-Didehydro-neophysalin B significantly inhibited H₂O₂-induced RLE-6TN cell damage. It also activated the Nrf2 signaling pathway which was evident from the increased transcription of antioxidant responsive of KLF9, NQO1, Keap-1, and HO-1. Nrf2 was found to be a potential target of 4,7-didehydro-neophysalin B. The protein levels of Bcl-2 and Bcl-xL were increased while Bax and p53 were decreased significantly. Flow cytometry showed that 4,7-didehydro-neophysalin B protected RLE-6TN cells from apoptosis and has improved the oxidative damage. This study provided a promising evidence that 4,7-didehydro-neophysalin B can be a therapeutic option for oxidative stress in respiratory diseases.