Inorganic Polyphosphate Triggers NLRP3 Inflammasome and Promotes the Epithelial-to-Mesenchymal Transition and...

Inorganic polyphosphate (iPolyP) is a ubiquitous molecule composed of a variable number of orthophosphate units. Recent studies have highlighted its involvement in colorectal cancer (CRC) cell proliferation. However, further investigations are needed to elucidate its role in CRC cell progression and migration, as well as its influence on the tumor microenvironment. This study focuses on the inorganic polyphosphate (iPolyP)/transient receptor potential cation channel subfamily M member 8 (TRPM8) axis and its impact on CRC progression. To investigate these issues, western blotting, fixed and live cells immunofluorescence, 2D and 3D cell culture on CRC-patient derived tissues, ELISA, and wound healing assays were performed. Our results show that inorganic polyphosphate induces the expression of epithelial-to-mesenchymal transition (EMT) markers in CRC cells. Furthermore, the iPolyP/TRPM8 axis indirectly promotes tumor growth through activation of the Nucleotide-binding oligomerization domain, Leucine-rich Repeat and Pyrin domain-containing protein 3 (NLRP3) inflammasome in immune cells, leading to increased levels of the pro-inflammatory cytokine interleukin-1β (IL-1β) in the tumor microenvironment (TME), thereby advancing CRC. These findings suggest that targeting the iPolyP/TRPM8 pathway may be a promising strategy to inhibit CRC progression and metastasis.