Mechanism of Yishen Tonglong Decoction inhibiting TLR4/p38 MAPK/NF-κB signaling pathway against prostate cancer via upregulating miR-145-5p

Objective

To investigate the mechanism of Yishen Tonglong Decoction (益肾通癃汤, YSTLD) inhibiting the toll-like receptor 4/p38 mitogen activated protein kinases/nuclear factor kappa-B (TLR4/p38 MAPK/NF-κB) signaling pathway against prostate cancer by up-regulating miR-145-5p.

Methods miRNA microarray technology was used to detect the changes of miRNA expression profile in prostate cancer PC-3 cells treated with YSTLD, and miRNAs with marked differences in miRNA microarray results were screened and validated by real-time polymerase chain reaction (qRT-PCR). Lentiviral transfection of miR-145-5p into prostate cancer PC-3 cells, Cell Counting Kit-8 (CCK8) assay, and scratch assay were adopted to detect the effects of miR-145-5p on prostate cancer PC-3 cell proliferation and migration. qRT-PCR and Western blot were employed to detect the effects of miR-145-5p on TLR4/p38 MAPK/NF-κB signaling pathway and the expression levels of apoptosis-related genes caspase3, tumor necrosis factor-α (TNF-α), Bax, and Bcl-2. qRT-PCR and Western blot were used to detect the effects of serum containing YSTLD on miR-145-5p, TLR4/p38 MAPK/NF-κB signaling pathway, and the expression levels of apoptosis-related genes caspase3, TNF-α, Bax, and Bcl-2.

Results

The expression levels of 35 miRNAs in prostate cancer PC-3 cells treated with YSTLD were significantly different from those in the control group, with miR-145-5p being the most significantly different; qRT-PCR validation revealed that the miR-145-5p levels in prostate cancer PC-3 cells treated with YSTLD were significantly higher than those in the DMSO control group (P < 0.05). After lentiviral transfection of miR-145-5p into prostate cancer PC-3 cells, miR-145-5p was found to inhibit the proliferation and migration of prostate cancer PC-3 cells. Overexpression of miR-145-5p up-regulated expression levels of caspase3, TNF-α, and Bax mRNA, and down-regulated expression levels of p38 MAPK, p65 NF-κB, and Bcl-2 mRNA in prostate cancer PC-3 cells (P < 0.05), while up-regulated caspase3 protein expression levels in prostate cancer PC-3 cells and down-regulated expression levels of TLR4, p38 MAPK, and p65 NF-κB protein (P < 0.05). Serum containing YSTLD could up-regulate the expression levels of caspase3, TNF-α, and Bax mRNA, and down-regulate the mRNA expression levels of p38 MAPK, p65 NF-κB, Bcl-2, and TNF receptor-associated factor 1 (TRAF1) in prostate cancer PC-3 cells after intervening prostate cancer PC-3 cells (P < 0.05). Simultaneously, it up-regulated the expression levels of caspase3 protein and down-regulated the protein expression levels of TLR4, p38 MARK, p65 NF-κB, and TRAF1 in prostate cancer PC-3 cells (P < 0.05).

Conclusion

YSTLD can promote apoptosis of prostate cancer PC-3 cells by up-regulating the expression level of miR-145-5p and inhibiting TLR4/p38 MAPK/NF-κB signaling pathway, which may be an important mechanism of YSTLD against prostate cancer.