Kaempferol blocks neutrophil extracellular traps formation and reduces tumour metastasis by inhibiting ROS-PAD4 pathway.

Kaempferol (kaem) is a dietary flavonoid found in a variety of fruits and vegetables. The inhibitory effects of kaem on primary tumour growth have been extensively investigated; however, its effects on tumour metastasis are largely unknown. In the present study, we found that kaem significantly suppresses both primary tumour growth and lung metastasis in mouse breast tumour model. Furthermore, decreased expression of citrullinated histone H3 (H3-cit), a biomarker of neutrophil extracellular traps (NETs), had been founded in metastatic lung upon treated with kaem. The reduction of H3-cit is not, however, due to the cytotoxicity of kaem on neutrophils since the frequency of CD11b+ Ly6G+ neutrophils did not change in lung, tumour or blood in the presence of kaem. We then confirm the anti-NETs effects of kaem in vitro by co-culturing mouse neutrophils and kaem. Supplementing the neutrophils with GSK484, a potent NET inhibitor, totally abrogated the inhibitory effects of kaem on tumour metastasis while having little or no impact on primary tumour growth, indicating the specificity of kaem acting on NET formation and tumour metastasis. We also found that kaem suppressed ROS production in mouse bone-marrow derived neutrophils. Supplementing with the ROS scavenger DPI abrogated kaem's effects on NET formation, suggesting the involvement of kaempferol in NADPH/ROS-NETs signalling. Finally, we applied the kaem on NET-deficient PAD4-/- mice and found decreased primary tumour volume and weight but similar lung metastatic tumour with kaempferol treatment. Therefore, our findings reveal a novel mechanism of kaem in breast cancer development by targeting NETs induced tumour metastasis.

LncRNA SNHG5 promotes the glycolysis and proliferation of breast cancer cell through regulating BACH1 via targeting miR-299.

BACKGROUND: Breast cancer (BC) is one of the most common malignant tumors in women. Accumulating studies have been reported that long non-coding RNA (lncRNA) SNHG5 is highly expressed in BC. However, the specific molecular mechanism of SNHG5 in BC is unclear. METHODS: Gene and protein expressions in BC cell were detected by qRT-PCR and western blotting. The proliferation and cell cycle were measured using colony formation assay and flow cytometry analysis, separately. The glucose consumption and lactate production were determined by using the glucose assay kit and lactate assay kit. A dual-luciferase reporter assay was performed to measure the interaction between miR-299 and SNHG5 or BACH1. RESULTS: SNHG5 and BACH1 expressions were increased in BC cell while miR-299 level was decreased. SNHG5 increased BACH1 expression by directly targeting miR-299. SNHG5 silencing or miR-299 overexpression suppressed the proliferation of BC cell, arrested the cell cycle in the G1 cell phase, and decreased the glucose consumption and lactate production of BC cell. However, inhibition of miR-299 or overexpression of BACH1 could reverse the inhibitory effects of sh-SNHG5 on cell proliferation and glycolysis in BC. CONCLUSION: SNHG5 promoted the BC cell growth and glycolysis through up-regulating BACH1 expression via targeting miR-299. These findings may improve the diagnostic and therapeutic approaches to BC.