Mechanistic insights into xanthomicrol as the active anti-HCC ingredient of Phytolacca acinosa Roxb.: A network pharmacology analysis and transcriptomics integrated experimental verification.

ETHNOPHARMACOLOGICAL RELEVANCE: Phytolacca acinosa Roxb. (PAR) is a Traditional Chinese Medicinal (TCM) plant with a broad global distribution encompassing 35 species, four of which are found in the People's Republic of China. It occupies a significant role in both Oriental and American traditional medicine, employed in treating a range of conditions such as edema, inflammation, dermatitis, and rheumatism. PAR is also used as a molluscicide and for addressing tumors and bronchitis. The plant is documented in the Chinese Pharmacopoeia and has a longstanding history in TCM, particularly for its diuretic properties and in treating ailments such as edema, swelling, and ulcers. Notably, PAR has demonstrated potent inhibitory effects against the A549 human lung cancer cell line, underscoring its potential in contributing to the development of novel cancer therapeutics. AIM OF THE STUDY: The research aims to elucidate the active components of PAR and their mechanisms in treating hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Employing network pharmacology, this study predicted the principal active compounds and key targets of PAR. A holistic methodology incorporating biological network analysis, transcriptomics sequencing, molecular docking, and molecular dynamics (MD) simulations was utilized to forecast the effects of PAR on HCC, with empirical evidence supporting these findings. RESULTS: Network pharmacology identified xanthomicrol as the foremost active compound in PAR. The tumor-suppressive functions of PAR, as indicated by KEGG pathway analysis and transcriptomics sequencing, predominantly occur via the PI3K/AKT pathway. Molecular docking and dynamics simulations demonstrated the high affinity of xanthomicrol towards TNF, MMP9, PPARG, KDR, and MMP2. In vivo experiments verified the efficacy of xanthomicrol in curtailing HCC tumor growth, while in vitro assessments revealed its substantial impact on the proliferation and apoptosis of HepG2 and HCCLM3 cells. Moreover, the study indicates that xanthomicrol may modulate the expression of TNF, MMP9, PPARG, KDR, and MMP2 in HCC cells and inhibit the activation of the PI3K/AKT pathway. CONCLUSIONS: Xanthomicrol, a principal active component of PAR, has been identified to impede the growth of HCC by targeting the PI3K/Akt/MMP9 pathway. This insight could enhance therapeutic approaches for HCC.

Expression of the two-component regulator StyS/StyR enhanced transcription of the styrene monooxygenase gene styAB and indigo biosynthesis in Escherichia coli.

Indigo, an economically important dye, could be biosynthesized from indole by catalysis of the styrene monooxygenase StyAB. To enhance indigo biosynthesis, the styAB gene and its transcription regulator gene styS/styR in styrene catabolism were cloned from Pseudomonas putida and coexpressed in Escherichia coli. The presence of the intact regulator gene styS/styR dramatically increased the transcriptional levels of styA and styB by approximately 120-fold in the recombinant strain SRAB2 with coexpression of styS/styR and styAB compared to the control strain ABST with solo expression of styAB. A yield of 67.6 mg/L indigo was detected in strain SRAB2 after 24 h of fermentation with 120 µg/mL indole, which was approximately 14-fold higher than that in the control strain ABST. The maximum yield of indigo was produced from 160 µg/mL indole in fermentation of strain SRAB2. However, the addition of styrene to the media significantly inhibited the transcription of styA and styB and consequent indigo biosynthesis in recombinant E. coli strains. Furthermore, the substitution of indole with tryptophan as the fermentation substrate remarkably boosted indigo production, and the maximal yield of 565.6 mg/L was detected in strain SRAB2 in fermentation with 1.2 mg/mL tryptophan. The results revealed that the regulation of styAB transcription by the two-component regulator StyS/StyR in styrene catabolism in P. putida was effective in E. coli, which provided a new strategy for the development of engineered E. coli strains with the capacity for highly efficient indigo production.