Andrographolide Inhibits Lytic Reactivation of Epstein-Barr Virus by Modulating Transcription Factors in Gastric Cancer

Andrographolide Alleviates Oxidative Damage and Inhibits Apoptosis Induced by IHNV Infection via CTSK/BCL2/Cytc Axis

Infectious hematopoietic necrosis virus (IHNV) is an important pathogen that causes significant economic losses to salmon trout farming. Although vaccines have been invented for the treatment of IHNV, findings from our previous survey show that breeding enterprises and farmers require effective oral drugs or immune enhancers. However, studies on the development of oral drugs are limited. In the present study, we used bioinformatics methods to predict the protein targets of andrographolide (Andro) in IHNV. Cells were infected with IHNV, and the effect of andrographolide was explored by evaluating the expression levels of genes implicated in oxidative stress, activities of antioxidant enzymes, and the expression of genes implicated in apoptosis and necrosis. In the present study, cells were divided into NC, IHNV, IHNV+10 μM andrographolide, and IHNV+20 μM andrographolide groups. qRT-PCR was performed to determine the expression level of genes, and an antioxidant enzyme detection kit was used to evaluate the activities of antioxidant enzymes. Fluorescent staining was performed using a reactive oxygen species detection kit (ROS) and Hoechst 33342/PI double staining kit, and the mechanism of alleviation of apoptosis and oxidative stress andrographolide after IHNV infection was determined. The results indicated that andrographolide inhibits viral growth by binding to the NV protein of IHNV and increasing the antioxidant capacity of the body through the CTSK/BCL2/Cytc axis, thereby inhibiting the occurrence of IHNV-induced apoptosis. This is the first study to explore the antagonistic mechanism of action of andrographolide in alleviating IHNV infection. The results provide valuable information on alternative strategies for the treatment of IHNV infection during salmon family and provide a reference for the use of andrographolide as an antioxidant agent in agricultural settings.

Andrographolide causes p53-independent HCC cell death through p62 accumulation and impaired DNA damage repair

BACKGROUND

Hepatocellular carcinoma (HCC) is a highly lethal cancer characterized by dominant driver mutations, including p53. Consequently, there is an urgent need to search for novel therapeutic agents to treat HCC. Andrographolide (Andro), a clinically available anti-inflammatory phytochemical agent, has shown inhibitory effects against various types of cancer, including HCC. However, the underlying molecular mechanisms of its action remain poorly understood.

PURPOSE

This study aims to investigate the molecular mechanisms by which p53 and p62 collectively affect Andro-induced HCC cell death, using both in vitro and in vivo models.

METHODS

In vitro cellular experiments were conducted to examine the effects of Andro on cell viability and elucidate its mechanisms of action. In vivo xenograft experiments further validated the anti-cancer effects of Andro.

RESULTS

Andro induced dose- and time-dependent HCC cell death while sparing normal HL-7702 hepatocytes. Furthermore, Andro caused DNA damage through the generation of reactive oxygen species (ROS), a critical event leading to cell death. Notably, HCC cells expressing p53 exhibited greater resistance to Andro-induced cell death compared to p53-deficient cells, likely due to the ability of p53 to induce G2/M cell cycle arrest. Additionally, Andro-induced p62 aggregation led to the proteasomal degradation of RAD51 and 53BP1, two key proteins involved in DNA damage repair. Consequently, silencing or knocking out p62 facilitated DNA damage repair and protected HCC cells. Importantly, disruption of either p53 or p62 did not affect the expression of the other protein. These findings were further supported by the observation that xenograft tumors formed by p62-knockout HCC cells displayed increased resistance to Andro treatment.

CONCLUSION

This study elucidates the mechanistic basis of Andro-induced HCC cell death. It provides valuable insights for repurposing Andro for the treatment of HCC, regardless of the presence of functional p53.

The Dual Functions of Andrographolide in the Epstein-Barr Virus-Positive Head-and-Neck Cancer Cells: The Inhibition of Lytic Reactivation of the Epstein-Barr Virus and the Induction of Cell Death

Andrographolide, a medicinal compound, exhibits several pharmacological activities, including antiviral and anticancer properties. Previously, we reported that andrographolide inhibits Epstein-Barr virus (EBV) lytic reactivation, which is associated with viral transmission and oncogenesis in epithelial cancers, including head-and-neck cancer (HNC) cells. However, the underlying mechanism through which andrographolide inhibits EBV lytic reactivation and affects HNC cells is poorly understood. Therefore, we investigated these mechanisms using EBV-positive HNC cells and the molecular modeling and docking simulation of protein. Based on the results, the expression of EBV lytic genes and viral production were significantly inhibited in andrographolide-treated EBV-positive HNC cells. Concurrently, there was a reduction in transcription factors (TFs), myocyte enhancer factor-2D (MEF2D), specificity protein (SP) 1, and SP3, which was significantly associated with a combination of andrographolide and sodium butyrate (NaB) treatment. Surprisingly, andrographolide treatment also significantly induced the expression of DNA Methyltransferase (DNMT) 1, DNMT3B, and histone deacetylase (HDAC) 5 in EBV-positive cells. Molecular modeling and docking simulation suggested that HDAC5 could directly interact with MEF2D, SP1, and SP3. In our in vitro study, andrographolide exhibited a stronger cytotoxic effect on EBV-positive cells than EBV-negative cells by inducing cell death. Interestingly, the proteome analysis revealed that the expression of RIPK1, RIPK3, and MLKL, the key molecules for necroptosis, was significantly greater in andrographolide-treated cells. Taken together, it seems that andrographolide exhibits concurrent activities in HNC cells; it inhibits EBV lytic reactivation by interrupting the expression of TFs and induces cell death, probably via necroptosis.

Andrographolide Inhibits Epstein–Barr Virus Lytic Reactivation in EBV-Positive Cancer Cell Lines through the Modulation of Epigenetic-Related Proteins

Reactivation of Epstein–Barr virus (EBV) is associated with EBV-associated malignancies and is considered to be a benefit target for treatment. Andrographolide is claimed to have antiviral and anti-tumor activities. Therefore, this study aimed to investigate the effect of andrographolide on the inhibition of EBV lytic reactivation in EBV-positive cancer cells. The cytotoxicity of andrographolide was firstly evaluated in EBV-positive cancer cells; P3HR1, AGS-EBV and HONE1-EBV cells, using an MTT assay. Herein, the spontaneous expression of EBV lytic genes; BALF5, BRLF1 and BZLF1, was significantly inhibited in andrographolide-treated cells. Accordingly, andrographolide inhibited the expression of Zta and viral production in sodium butyrate (NaB)-induced EBV lytic reactivation. Additionally, proteomics and bioinformatics analysis revealed the differentially expressed proteins that inhibit EBV lytic reactivation in all treated cell lines were functionally related with the histone modifications and chromatin organization, such as histone H3-K9 modification and histone H3-K27 methylation. Taken together, andrographolide inhibits EBV reactivation in EBV-positive cancer cells by inhibiting EBV lytic genes, probably, through the histone modifications.