Quercetin inhibits the metabolism of arachidonic acid by inhibiting the activity of CYP3A4, thereby inhibiting the progression of breast cancer.

BACKGROUND: Recent years have witnessed impressive growth in applying natural medicine in tumor treatment. Saffron is reported to elicit an inhibitory property against BC. Herein, we sought to explore the specific components and mechanistic basis of saffron's anti-breast carcinoma (BC) function. METHODS: Bioinformatics analysis was employed to analyze saffron components' anti-BC activity and screen the corresponding target genes involved in BC. Then, the roles of the main saffron ingredient quercetin in the activity of BC cells were examined using CCK-8, MTS, flow cytometry, colony formation, Transwell, and Gelatin zymogram assays. Additionally, the interactions among Quercetin, EET, and Stat3 were assessed by immunofluorescence and Western blot, and LC-MS/MS determined the levels of AA, EETs, and CYP3A. Finally, BC xenograft mouse models were established to verify the anti-BC function of Quercetin in vivo. RESULTS: Quercetin, the main active component of saffron, inhibited BC progression. Quercetin suppressed BC cell growth, migration, and invasion and inhibited CYP3A4 expression and activity in BC. Mechanistically, Quercetin down-regulated CYP3A4 to block the nuclear translocation of Stat3 by decreasing the metabolization of AA to EETs, thereby alleviating BC. Moreover, exogenously added EETs counteracted the anti-tumor effect of Quercetin on BC. Quercetin also inhibited the tumor growth of tumor-bearing nude mice. CONCLUSION: Quercetin could inhibit the activity of CYP3A to down-regulate AA metabolites EETs, consequently hampering p-Stat3 and nuclear translocation, thus impeding BC development.

Arsenite inhibits the function of CD133+ CD13+ liver cancer stem cells by reducing PML and Oct4 protein expression.

Cancer stem cells (CSCs) can form new tumors and contribute to post-operative recurrence and metastasis. We showed that CD133+CD13+ hepatocytes isolated from HuH7 cells and primary HCC cells display biochemical and functional characteristics typical of CSCs, suggesting that CD133+CD13+ hepatocytes in primary HCC tumors function as CSCs. We also found that arsenite treatment reduced the viability and stemness of CD133+CD13+ hepatocytes, enhanced the sensitivity of HuH7 cells to pirarubicin, and reduced the tumorigenicity of CD133+CD13+ hepatocytes xenografts in mice. The effects of sodium arsenite treatment in CD133+CD13+ hepatocytes were mediated by the post-transcriptional suppression of PML expression and the inhibition of Oct4, Sox2, and Klf4 expression at the transcriptional level. Incomplete rescue of Oct4 expression in arsenic-treated cells ectopically expressing an siRNA-resistant PML transcript suggested that OCT4 regulation in liver CSCs involves other factors in addition to PML. Our findings provide evidence of a specific role for PML in regulating Oct4 levels in liver CSCs and highlight the clinical importance of arsenic for improving the efficacy of other chemotherapeutic agents and the prevention of post-operative HCC recurrence and metastasis.