TLR5: A prognostic and monitoring indicator for triple-negative breast cancer.

Abstract

A novel, highly selective biomarker is urgently needed to predict and monitor triple-negative breast cancer (TNBC) because targeting molecules are not currently available. Although associated with various malignant tumors, the role of toll-like receptor 5 (TLR5) in TNBC remains uncertain. We aimed to define the effects of TLR5 in TNBC to determine whether it could serve as a prognostic and monitoring indicator for TNBC. We established TNBC cell line 4T1 with low TLR5 expression (GFP tag; TLR5- 4T1) and with normal TLR5 expression (GFP tag; TLR5+ 4T1) using lentivirus-shRNA-TLR5 knockdown transfection and negative lentivirus transfection, respectively. Detected by western blot and qPCR, we found knockdown of TLR5 resulted in decreased expression of TLR5 and E-cadherin and increased expression of N-cadherin, vimentin, fibronectin, TRAF6, SOX2, and Twist1, which were related to EMT (epithelial-mesenchymal transition). In addition, downregulation of TLR5 increased the invasion and migration of 4T1 cells in vitro, which were investigated by CCK-8 and wound healing, as well as transwell assay and colony formation. Furthermore, the metastatic ability of TLR5- 4T1 cells to the lungs was also increased compared to TLR5+ 4T1 cells in vivo. To verify the effect of TLR5 as a monitor indicator, mice bearing TLR5+ and TLR5- 4T1 tumors injected with 125I-anti-TLR5 mAb or isotype 125I-IgG were assessed by whole body phosphor-autoradiography and fluorescence imaging in vivo. Phosphor-autoradiography of model mice revealed early tumors at 6 days after inoculation with TLR5+ 4T1, but not TLR5- 4T1 cells. Intratumoral accumulation of radioactivity positively correlated with TLR5 expression, and fluorescence imaging in vivo revealed both TLR5+ and TLR5- 4T1 tumors. Our results suggested that downregulation of TLR5 in TNBC increased tumor invasiveness and EMT expression via TRAF6 and SOX2 pathway and TLR5 could serve as a prognostic and monitoring indicator for TLR5-positive tumors.

• Authors: Dai Shi, Shanshan Zhao, Wen Jiang, Chao Zhang, Ting Liang, Guihua Hou
• Journal: Cell death & disease (Cell Death Dis) Vol. 10 Issue 12 Pg. 954 (12 18 2019) ISSN: 2041-4889 [Electronic] England
• PMID: 31852883 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• SOXB1 Transcription Factors
• Sox2 protein, mouse
• TLR5 protein, human
• TNF Receptor-Associated Factor 6
• TRAF6 protein, mouse
• Tlr5 protein, mouse
• Toll-Like Receptor 5
• Vimentin

Topics

• Animals
• Biomarkers, Tumor (genetics)
• Cell Line, Tumor
• Cell Movement (genetics)
• Cell Proliferation (genetics)
• Disease Models, Animal
• Epithelial-Mesenchymal Transition (genetics)
• Female
• Gene Expression Regulation, Neoplastic (genetics)
• Humans
• Mice
• Neoplasm Invasiveness (genetics, pathology)
• Prognosis
• SOXB1 Transcription Factors (genetics)
• TNF Receptor-Associated Factor 6 (genetics)
• Toll-Like Receptor 5 (genetics)
• Triple Negative Breast Neoplasms (genetics, pathology)
• Vimentin (genetics)