GOLPH3-STIP1 Complex Activates STAT3 through Exosome Secretion to Induce
Colon Cancer Metastasis
Abstract
Background: The functions of GOLPH3, STIP1, and the STAT3 signaling
pathway in the invasion and migration of CC cells were examined in this
study. Method: High-speed centrifugation was used to collect the
exosomes. The expression of GOLPH3, STIP1, and epithelial-mesenchymal
transition (EMT)-related proteins in CC tissues, cells, and exosomes
were analyzed using Western blotting (WB) experiments. The abilities of
CC cell invasion and migration were evaluated by the Transwell assay.
The binding relationship between GOLPH3 and STIP1 was validated through
Co-immunoprecipitation (Co-IP), and their sublocalization in CC cells
was determined by immunofluorescence detection under laser confocal
microscopy. Immunohistochemistry (IHC) experiments detected the
expression levels of each protein in the transplanted tumor mass. Animal
experiments confirmed the impact of the GOLPH3/STIP1/STAT3 regulatory
axis on the CC growth. Results: In CC tissues and cells, GOLPH3 was
highly expressed, and silencing GOLPH3 not only greatly reduced CC cell
invasion and migration but also prevented EMT. Furthermore, GOLPH3 and
STIP1 interacted in CC cells, and the GOLPH3-STIP1 complex affected the
capacity for cell invasion and migration by triggering the STAT3
signaling pathway. Noteworthily, GOLPH3, and STIP1 could also be
detected in CC cell exosomes, and the exosomes carried the GOLPH3-ST1P1
complex to act on CC cells to activate intracellular STAT3 signaling,
ultimately affecting the cancer cell migration and invasion. The above
molecular regulatory mechanisms have also been validated in mice.
Conclusion: The GOLPH3-STIP1 complex acted on surrounding CC cells
through exosomes and activated the STAT3 signaling pathway to stimulate
CC cell invasion and migration