Aspartate Transporter SLC1A3 Promotes Colorectal Cancer via MDM2-p53 Pathway and M2 Macrophage Polarization.

Colorectal cancer (CRC) remains the most prevalent malignancy of the digestive system globally and ranks second in cancer-related deaths worldwide. Metabolic reprogramming is one of the hallmarks of cancer. Aspartate is a proteinogenic non-essential amino acid with several essential functions in cancer cells. SLC1A3 is the main aspartate transporter, but its role in CRC needs to be elucidated. We found that SLC1A3 is significantly overexpressed in CRC tissues compared to adjacent normal tissues, and elevated SLC1A3 expression is associated with poor prognosis. Further, SLC1A3 could enhance the proliferation, invasion, migration of CRC cells and organoids by activating the DAG/PKC/MDM2 signaling axis. In addition, we revealed that SLC1A3 in CRC cells could induce the immunosuppressive M2 phenotype of macrophages via upregulating IL17c and CSF2. In sum, these findings suggest that SLC1A3 plays a dual role in CRC progression and may represent a promising target for therapeutic intervention.