Peng C, Chen XT, Xu H, Chen LP, Shen W. Role of the CXCR4/ALK5/Smad3 Signaling Pathway in Cancer-Induced Bone Pain.
J Pain Res 2020;
13:2567-2576. [PMID:
33116799 PMCID:
PMC7569080 DOI:
10.2147/jpr.s260508]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 09/15/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose
The chemokine receptor, CXCR4, and the transforming growth factor-beta receptor, ALK5, both contribute to various processes associated with the sensation of pain. However, the relationship between CXCR4 and ALK5 and the possible mechanisms promoted by ALK5 in the development of pain have not been evaluated.
Materials and Methods
Tumor cell implantation (TCI) technology was used to generate a model of cancer-induced bone pain (CIBP) in rats; intrathecal (i.t.) injections of small interfering (si) RNAs targeting CXCR4 and the ALK5-specific inhibitor, RepSox, were performed. Behavioral outcomes, Western blotting, and immunofluorescence techniques were used to evaluate the expression of the aforementioned specific target proteins in the CIBP model.
Results
The results revealed that i.t. administration of siRNAs targeting CXCR4 resulted in significant reductions in both mechanical and thermal hyperalgesia in rats with CIBP and likewise significantly reduced the expression of ALK5 in the spinal cord. Similarly, i.t. administration of RepSox also resulted in significant reductions in mechanical and thermal hyperalgesia in rats with CIBP together with diminished levels of spinal p-Smad3.
Conclusion
Taken together, our results suggest that CXCR4 expression in the spinal cord may be a critical mediator of CIBP via its capacity to activate ALK5 and downstream signaling pathways.
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