Inhibition of MZF1/c-MYC Axis by Cantharidin Impairs Cell Proliferation in Glioblastoma

Norcantharidin inhibits TOP2A expression via H3K27me3 mediated epigenetic regulation to alleviate the progression of hepatocellular carcinoma

Background

Norcantharidin (NCTD), a bioactive compound derived from traditional Chinese medicine, has demonstrated promising anticancer activity against multiple malignancies, particularly hepatocellular carcinoma (HCC). However, its epigenetic regulatory mechanisms and associated transcriptional consequences remain poorly characterized.

Methods

In this study, we integrated biochemical assays with a panel of cellular analyses assessing cell viability, proliferation, colony formation, and migratory capacity to investigate NCTD's therapeutic potential in HCC progression. Potential molecular targets of NCTD were systematically identified through integrated network pharmacology approaches. Chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) was performed to quantify H3K27me3 enrichment level at the TOP2A locus in NCTD-treated HCC cells. Molecular docking simulations were employed to examine structural interactions between NCTD and EZH2 (enhancer of zeste homolog 2), while co-immunoprecipitation assays were further conducted to validate protein-protein interactions between EZH2 and protein phosphatase 1 (PP1).

Results

We identified topoisomerase IIα (TOP2A) as a critical molecular target mediating NCTD's anti-HCC effects. Functional characterization revealed that NCTD significantly attenuated HCC cell proliferation and induced G2/M phase cell cycle arrest through disruption of the TOP2A-p53 signaling axis. Mechanistic investigations demonstrated that NCTD epigenetically suppresses TOP2A transcription via PRC2 (Polycomb Repressive Complex 2)-mediated deposition of the repressive histone mark H3K27me3 at the TOP2A promoter. Structural biology analyses confirmed direct binding of NCTD to EZH2 protein, consequently impairing PP1-mediated dephosphorylation and enhancing PRC2 complex stability.

Conclusion

Our findings establish that NCTD exerts anticancer effects in HCC through epigenetic silencing of TOP2A. This work not only elucidates a novel pharmacoepigenetic mechanism underlying NCTD's antitumor activity but also provides translational rationale for developing PRC2-targeted therapeutic strategies in HCC management.

Integrative approach using network pharmacology, bioinformatics, and experimental methods to explore the mechanism of cantharidin in treating colorectal cancer

Cantharidin, a terpenoid produced by blister beetles, has been used in traditional Chinese medicine to treat various ailments and cancers. However, its biological activity, impact, and anticancer mechanisms remain unclear. The Cantharidin chemical gene connections were identified using various databases. The GSE21815 dataset was used to collect the gene expression information. Differential gene analysis and gene ontology analyses were performed. Gene set enrichment analysis was used to assess the activation of disease pathways. Weighted gene co-expression network analysis and differential analysis were used to identify illness-associated genes, examine differential genes, and discover therapeutic targets via protein-protein interactions. MCODE analysis of major subgroup networks was used to identify critical genes influenced by Cantharidin, examine variations in the expression of key clustered genes in colorectal cancer vs. control samples, and describe the subject operators. Single-cell GSE188711 dataset was preprocessed to investigate Cantharidin's therapeutic targets and signaling pathways in colorectal cancer. Single-cell RNA sequencing was utilized to identify 22 cell clusters and marker genes for two different cell types in each cluster. The effects of different Cantharidin concentrations on colorectal cancer cells were studied in vitro. One hundred and ninety-seven Cantharidin-associated target genes and 480 critical genes implicated in the development of the illness were identified. Cantharidin significantly inhibited the proliferation and migration of HCT116 cells and promoted apoptosis at certain concentrations. Patients on current therapy develop inherent and acquired resistance. Our study suggests that Cantharidin may play an anti-CRC role by modulating immune function.

Fluvoxamine Exerts Sigma-1R to Rescue Autophagy via Pom121-Mediated Nucleocytoplasmic Transport of TFEB

Expansion of the GGGGCC-RNA repeat is a known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), which currently have no cure. Recent studies have indicated the activation of Sigma-1 receptor plays an important role in providing neuroprotection, especially in ALS and Alzheimer's disease. Nevertheless, the mechanisms underlying Sigma-1R activation and its effect on (G4C2)n-RNA-induced cell death remain unclear. In this study, we demonstrated that fluvoxamine is a Sigma-1R agonist that can increase chaperone activity and stabilize the protein expression of Pom121 in (G4C2)31-RNA-expressing NSC34 cells, leading to increased colocalization at the nuclear envelope. Interestingly, fluvoxamine treatment increased Pom121 protein expression without affecting transcription. In C9orf72-ALS, the nuclear translocation of TFEB autophagy factor decreased owing to nucleocytoplasmic transport defects. Our results showed that pretreatment of NSC34 cells with fluvoxamine promoted the shuttling of TFEB into the nucleus and elevated the expression of LC3-II compared to the overexpression of (G4C2)31-RNA alone. Additionally, even when used alone, fluvoxamine increases Pom121 expression and TFEB translocation. To summarize, fluvoxamine may act as a promising repurposed medicine for patients with C9orf72-ALS, as it stabilizes the nucleoporin Pom121 and promotes the translocation of TFEB in (G4C2)31-RNA-expressing NSC34 cells.