Inhibition of integrin α3 suppresses gastric cancer progression via STAT3-mediated regulation of SLC1A5-dependent glutamine uptake.

[BACKGROUND] Gastric cancer (GC) remains one of the most lethal malignancies, primarily due to limited treatment efficacy and its strong metastatic potential. The identification of new molecular targets is therefore crucial for enhancing therapeutic strategies and improving clinical outcomes.

[METHODS] The expression of ITGA3 was investigated in clinical GC tissue samples, and its association with patient prognosis was evaluated. Both in vitro and in vivo assays were employed to investigate the functional role of ITGA3 in GC cell proliferation and invasion. To uncover the underlying molecular mechanisms, integrated proteomic and transcriptomic analyses were performed. Mechanistic validation was subsequently carried out using Western blotting, immunofluorescence, nuclear-cytoplasmic fractionation, dual-luciferase reporter, and chromatin immunoprecipitation (ChIP) assays.

[RESULTS] Elevated ITGA3 expression was strongly correlated with an unfavorable prognosis in GC patients. Functional studies revealed that ITGA3 promotes tumor cell proliferation and invasion. Multi-omics analyses revealed that ITGA3 modulates glutamine metabolism by regulating the amino acid transporter SLC1A5 and engages the JAK-STAT3 signaling pathway. Silencing ITGA3 significantly reduced STAT3 nuclear translocation, suppressing SLC1A5 transcription and decreasing glutamine uptake. Both dual-luciferase reporter and ChIP assays confirmed that STAT3 directly binds to the promoter region of SLC1A5.

[CONCLUSIONS] ITGA3 acts as an oncogenic driver in GC by facilitating glutamine uptake via the STAT3-SLC1A5 signaling axis. These findings suggest that therapeutic targeting of this pathway could represent a promising approach for the clinical management of GC.