Synergistic effect of toosendanin and regorafenib against cell proliferation and migration by regulating WWOX signaling pathway in hepatocellular carcinoma

Toosendanin-induced liver damage through irreparable DNA damage and autophagy flow blockade

OBJECTIVE

The fruit of Melia toosendan Sieb. et Zucc. (MT) is known for its efficacy in relieving pain and treating roundworms. Toosendanin (TO) has been identified as a bioactive marker of MT, with hepatotoxic properties. This study offers a comprehensive investigation into the toxic mechanisms, involving TO-induced remaining DNA damage, cell cycle arrest, and the synergistic effect of autophagy flow disruption. It provides new insights into the clinical applications of MT and TO.

METHODS

TO was prepared at 50, 100, and 200 μM for a 48 h treatment of HepG2 cells, while zebrafish were administered at 50, 75, and 100 μM for 72 h. Transcriptomics and computational molecular simulations, including network pharmacology, molecular docking, and molecular dynamics simulation, were used for target prediction. Fluorescent probes, flow cytometry, quantitative real-time polymerase chain reaction, and western blotting were employed for mechanism verification.

RESULTS

TO disrupted the balance between reactive oxygen species and cellular antioxidant defense, resulting in mitochondrial damage and repression of DNA-dependent protein kinase catalytic subunit. This led to the inability to repair DNA damage and caused cell cycle arrest in the G1/S phase. As shown in computational molecular simulations and transcriptomics analysis, the repression of damaged organelle removal through autophagy flow disruption resulted in excessive injury and hepatocyte death.

CONCLUSION

By impairing DNA damage responses (DDRs) and autophagy, TO causes unrepaired DNA damage, which disrupts cell cycle progression through complex interactions with cyclin proteins and tumour suppressor genes, ultimately contributing to hepatotoxicity.

Toosendanin: upgrade of an old agent in cancer treatment

Toosendanin (TSN), a tetracyclic triterpenoid derived from Melia toosendan and M. azedarach, demonstrates broad application prospects in cancer treatment. Although previously employed as a pesticide, recent studies have revealed its potential therapeutic value in treating various types of cancer. TSN exerts an anticancer effect via mechanisms including proliferation inhibition, apoptosis induction, migration suppression, and angiogenesis inhibition. However, TSN's toxicity, particularly its hepatotoxicity, significantly limits its therapeutic application. This review explored the dual nature of TSN, evaluating both its anticancer potential and toxicological risks, emphasizing the importance of balancing these aspects in therapeutic applications. Furthermore, we investigated the incorporation of TSN into novel therapeutic strategies, such as Proteolysis-targeting chimeras (PROTAC) technology and nanotechnology-based drug delivery systems (DDS), which enhance treatment efficacy while mitigating toxicity in normal tissues.

The cumulative antitumor effects of regorafenib and radiotherapy in hepatocellular carcinoma

Regorafenib is a second-line standard treatment for hepatocellular carcinoma (HCC). However, the efficacy of regorafenib is often limited due to drug resistance, individual differences among patients, and irrational drug use. Radiotherapy (RT) is an important method of localized HCC treatment, and combining RT with other therapies may exert a synergetic antitumor effect. Platelet-derived growth factor receptor-like (PDGFRL) is a tumor suppressor in various solid tumors. However, the function of PDGFRL in HCC is still unknown. In this study, we explored whether regorafenib and RT exert a synergetic effect on the treatment of HCC. The antitumor effect and mechanisms of the combination of regorafenib and RT were verified in a xenograft mouse model in vivo and in HCC cells in vitro. The combination treatment significantly inhibited cell proliferation and promoted apoptosis both in vitro and in vivo. PDGFRL, a potential target of regorafenib, was increased after cumulative treatment in HCC cells, and PDGFRL suppressed HCC cell proliferation and promoted apoptosis by inhibiting STAT3 pathway activation. Furthermore, the cumulative antitumor effect was dependent on the upregulated expression of PDGFRL and inhibition of STAT3 signaling pathway activation in HCC cells. This study increased the understanding of the molecular mechanism underlying the effect of regorafenib plus RT on HCC and provided a theoretical basis for the clinical practice of HCC.

Toosendanin inhibits T-cell proliferation through the P38 MAPK signalling pathway

In recent years, immunosuppressants have shown significant success in the treatment of autoimmune diseases. Therefore, there is an urgent need to develop additional immunosuppressants that offer more options for patients. Toosendanin has been shown to have immunosuppressive activity in vitro as well as effects on autoimmune hepatitis (AIH) in vivo. Toosendanin did not induce apoptosis in activated T-cells and affect the survival rate of naive T-cells. Toosendanin did not affect the expression of CD25 or secretion of IL-2 by activated T-cells, and not affect the expression of IL-4 and INF-γ. Toosendanin did not affect the phosphorylation of STAT5, ERK, AKT, P70S6K. However, toosendanin inhibited proliferation of anti-CD3/anti-CD28 mAbs-activated T-cells with IC50 of (10 ± 2.02) nM. Toosendanin arrested the cell cycle in the G0/G1 phase, significantly inhibited IL-6 and IL-17A secretion, promoted IL-10 expression, and inhibited the P38 MAPK pathway. Finally, toosendanin significantly alleviated ConA-induced AIH in mice. In Summary, toosendanin exhibited immunosuppressive activity in vivo and in vitro. Toosendanin inhibits the proliferation of activated T-cells through the P38 MAPK signalling pathway, significantly suppresses the expression of inflammatory factors, enhances the expression of anti-inflammatory factors, and effectively alleviates ConA-induced AIH in mice, suggesting that toosendanin may be a lead compound for the development of novel immunomodulatory agents with improved efficacy and reduced toxicity.

Therapeutic potential of toosendanin: Novel applications of an old ascaris repellent as a drug candidate

Toosendanin (TSN), extracted from Melia. toosendan Sieb.et Zucc. and Melia. azedarach L., has been developed into an ascaris repellent in China. However, with the improvement of public health protection, the incidence of ascariasis has been reduced considerably, resulting in limited medical application of TSN. Therefore, it is questionable whether this old ascaris repellent can develop into a drug candidate. Modern studies have shown that TSN has strong pharmacological activities, including anti-tumor, anti-botulinum, anti-viral and anti-parasitic potentials. It also can regulate fat formation and improve inflammation. These researches indicate that TSN has great potential to be developed into a corresponding medical product. In order to better development and application of TSN, the availability, pharmacodynamics, pharmacokinetics and toxicology of TSN are summarized systematically. In addition, this review discusses shortcomings in the current researches and provides useful suggestions about how TSN developed into a drug candidate. Therefore, this paper illustrates the possibility of developing TSN as a medical product, aimed to provide directions for the clinical application and further research of TSN.

Small-molecule PROTAC mediates targeted protein degradation to treat STAT3-dependent epithelial cancer

The aberrant activation of STAT3 is associated with the etiology and progression in a variety of malignant epithelial-derived tumors, including head and neck squamous cell carcinoma (HNSCC) and colorectal cancer (CRC). Due to the lack of an enzymatic catalytic site or a ligand-binding pocket, there are no small-molecule inhibitors directly targeting STAT3 that have been approved for clinical translation. Emerging proteolysis targeting chimeric (PROTAC) technology-based approach represents a potential strategy to overcome the limitations of conventional inhibitors and inhibit activation of STAT3 and downstream genes. In this study, the heterobifunctional small-molecule-based PROTACs are successfully prepared from toosendanin (TSN), with 1 portion binding to STAT3 and the other portion binding to an E3 ubiquitin ligase. The optimized lead PROTAC (TSM-1) exhibits superior selectivity, potency, and robust antitumor effects in STAT3-dependent HNSCC and CRC - especially in clinically relevant patient-derived xenografts (PDX) and patient-derived organoids (PDO). The following mechanistic investigation identifies the reduced expression of critical downstream STAT3 effectors, through which TSM-1 promotes cell cycle arrest and apoptosis in tumor cells. These findings provide the first demonstration to our knowledge of a successful PROTAC-targeting strategy in STAT3-dependent epithelial cancer.

The therapeutic potential of natural products for treating pancreatic cancer

Pancreatic cancer is one of the most malignant tumors of the digestive tract, with the poor prognosis and low 5-year survival rate less than 10%. Although surgical resection and chemotherapy as gemcitabine (first-line treatment) has been applied to the pancreatic cancer patients, the overall survival rates of pancreatic cancer are quite low due to drug resistance. Therefore, it is of urgent need to develop alternative strategies for its treatment. In this review, we summarized the major herbal drugs and metabolites, including curcumin, triptolide, Panax Notoginseng Saponins and their metabolites etc. These compounds with antioxidant, anti-angiogenic and anti-metastatic activities can inhibit the progression and metastasis of pancreatic cancer. Expecting to provide comprehensive information of potential natural products, our review provides valuable information and strategies for pancreatic cancer treatment.