PYCR1 Promotes Esophageal Squamous Cell Carcinoma by Interacting With EGFR to Affecting the PI3K/Akt/mTOR Signaling Pathway

Background

The expression and functional role of pyrroline-5-carboxylate reductase 1 (PYCR1) in esophageal squamous cell carcinoma (ESCC) remain poorly understood. This study aimed to elucidate the role and underlying mechanisms of PYCR1 in ESCC.

Methods

We utilized an ESCC tissue microarray coupled with immunohistochemical staining to assess variability in PYCR1 protein expression among ESCC patients and evaluate its clinical relevance. PYCR1 was silenced in ESCC cell lines with short hairpin RNA (shRNA), followed by functional assays (colony formation, caspase 3/7 activity, methylthiazol tetrazolium, wound healing, and migration/invasion assays) to evaluate its role in ESCC progression. In vivo, mouse tumor xenograft models were used to examine PYCR1's impact on tumor growth. To identify downstream targets and pathways, we conducted coimmunoprecipitation, mass spectrometry, immunofluorescence, and proteomic analyses, validated by western blotting and rescue experiments.

Results

Our findings demonstrated a consistent upregulation of PYCR1 in ESCC tissues. Both in vitro and in vivo studies revealed that PYCR1 suppression significantly inhibited ESCC progression, impacting key processes such as proliferation, apoptosis, migration, and invasion. Mechanistically, PYCR1 was shown to interact with EGFR, promoting ESCC progression and metastasis by activating the PI3K/AKT/mTOR signaling pathways, which are integral to the aggressive behavior of the disease. Rescue experiments further confirmed that EGFR overexpression effectively reversed the inhibitory effects of PYCR1 knockdown in ESCC cells.

Conclusion

This study highlights the critical role of PYCR1 in driving ESCC progression and metastasis, underscoring its potential as a promising therapeutic target for managing this malignancy.