A study on the immunomodulation of polysaccharopeptide through the TLR4-TIRAP/MAL-MyD88 signaling pathway in PBMCs from breast cancer patients.

Context: Polysaccharopeptide (PSP), isolated from the Coriolus versicolor COV-1 strain, has been widely used as an immunoadjuvant for cancer immunotherapy. Objective: The present study was undertaken to examine the role of PSP on the TLR4-TIRAP/MAL-MyD88 signaling pathway in peripheral blood mononuclear cells (PBMCs) from breast cancer patients. Methods: For blockade of TLR4, cells were cultured with or without PSP and anti-TLR4 for 24 h, and then the mRNA and proteins (IL-12, IL-6, and TNF-alpha) levels in each group were detected by Q-PCR and ELISA. Meanwhile, Q-PCR and western blot analysis were used to detect the expression of TLR4-TIRAP/MAL-MyD88 pathway genes and proteins under the regulation of PSP. Results: As anticipated, the transcription and expression of genes (IL-12 and TNF-alpha) in the anti-TLR4 group were significantly downregulated compared with the control group, while genes (IL-12, IL-6 and TNF-alpha) in the PSP group were significantly upregulated. Moreover, the mRNA levels in the PSP+anti-TLR4 group were significantly upregulated compared with the anti-TLR4 group. The results of ELISA were as the same as Q-PCR. Genes, kinase phosphorylation levels and proteins in the TLR4 pathway were significantly upregulated by PSP. Conclusions: Collectively, our study revealed that PSP has an immunoregulatory effect through regulation of the TLR4-TIRAP/MAL-MyD88 signaling pathway.