BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a highly lethal malignancy with a 5-year survival rate of less than 20%, largely due to its high propensity for metastasis and recurrence. There is an urgent need to identify targeted therapeutic agents for this disease. While lysophosphatidylserine (LysoPS) and its receptor GPR174 are known regulators of immune and inflammatory processes, their mechanistic role in ESCC progression remains unexplored. This study investigates the LysoPS/GPR174 axis in driving ESCC metastasis and its underlying molecular pathways.

METHODS

LC-MS was used to measure LysoPS concentration, and Western blotting was performed for protein quantification. The correlation between GPR174 expression and ESCC prognosis was analyzed using ESCC tissue microarrays, immunohistochemistry, and Kaplan-Meier survival analysis. Wound healing and Transwell assays were carried out to evaluate the migratory and invasive capacities of cells. The proliferative ability of ESCC cell lines was assessed with the CCK-8 assay. Nuclear-cytoplasmic extraction assay was conducted to separate the nucleus and cytoplasm. Metastasis model of nude mouse was employed to investigate the metastasis of ESCC cell lines.

RESULTS

We found that the levels of LysoPS were significantly increased in metastatic ESCC tissues compared to nonmetastatic ESCC tissues. Moreover, a correlation was established between LysoPS-mediated tumor metastasis and GPR174 expression in ESCC. Our results also revealed that high expression of GPR174 in ESCC is associated with tumor metastasis and poor survival outcomes in ESCC patients. Further exploration of the underlying mechanism showed that LysoPS stimulates the up- regulation of GPR174 expression. The increased GPR174 then activates the cAMP-PKA signaling pathway. Subsequently, the active subunit of PKA translocates into the nucleus, where it phosphorylates CREB, thereby promoting the metastasis of ESCC. In vivo, GPR174 overexpression increased metastasis burden.

CONCLUSIONS

Our study demonstrates that the LysoPS/GPR174 axis, through the cAMP-PKA-CREB pathway, plays a crucial role in promoting the invasion and metastasis of ESCC. This highlights its potential as a novel target for predicting ESCC progression and may offer new insights for the development of targeted therapies for this deadly disease.