Inhibitory effect and mechanism of novel recombinant myricetin on triple negative breast cancer

ObjectiveTo investigate the inhibitory effect and mechanism of novel recombinant myricetin on 4T1 cells.

MethodsA new myricetin derivative was synthesized by modifying the chemical formula of myricetin.CCK-8 cell proliferation inhibition assay, and half inhibitory concentration(IC50) was calculated.The effects of novel myricetin on the migration and invasion of 4T1 cells were observed by scratch and Transwell assay.Flow cytometry was used to observe the changes of the cycle and apoptosis of 4T1 cells after the intervention of synthetic myricetin.The inhibitory effect of the novel myricetin on triple negative breast cancer(TNBC) was evaluated in the mouse tumor transplantation model in vivo.HE and TUNEL staining were used to observe the cell necrosis and apoptosis in transplanted tumor tissue sections of mice.Finally, the expression of related proteins(P53, Bcl2, Bax, Caspase 3) in 4T1 cells after intervention was detected by Western bloting.

ResultsThe IC50 was 5.5 μmol/mL.Compared with DMSO group, the cell count and migration rate of 4T1 cells were decreased after treated with 5.5 μmol/mL novel myricetin for 24 h(P<0.01).Flow cytometry and TUNEL staining of tumor tissue sections showed that compared with DMSO group, the number of apoptotic cells was increased, the proportion of G₁ phase cells was lower, the proportion of G₂ phase cells was higher, the tumor growth volume and tumor weight were smaller, p53 and Bcl2 proteins were down-regulated, Caspase 3 was up-regulated in 5.5 μmol/mL recombinant myricetin group(P<0.05 to P<0.01).

ConclusionsThe novel recombinant myricetin can induce the apoptosis and inhibit proliferation of 4T1 cells in vitro and in vivo, which may inhibit the proliferation of 4T1 cells by down-regulating p53 and induce the apoptosis of 4T1 cells through the Bcl2 mitochondrial apoptosis pathway.