PDIA3 driven STAT3/PD-1 signaling promotes M2 TAM polarization and aggravates colorectal cancer progression.

ABSTRACT

OBJECTIVE: This inquiry endeavors to delineate the influence of PDIA3 on tumor-associated macrophages within the realm of colorectal malignancies, whilst elucidating the intrinsic biochemical pathways. METHOD: Leveraging bioinformatics, we scrutinized the symbiosis between PDIA3, STAT3, and CD274. A xenograft model in immunodeficient murine served to assess PDIA3's impact on colorectal carcinogenesis. Further, Western blot analysis quantified the protein expression of PDIA3, p-STAT3, PD-1, XBP-1, assorted enzymes, and IL-6. Moreover, in vitro assays gauged SW480 cellular dynamics inclusive of migration, invasive potential, and proliferation. RESULTS: Bioinformatics exploration exposed PDIA3's elevated presence in diverse cancers, with a marked expression in colorectal cancer, as per TCGA and GEO repositories. Correlative studies showed PDIA3 positively aligning with STAT3 and CD274, the latter also associated with monocyte-derived macrophages. Comparative analysis of colorectal neoplasms and normal colon samples unveiled heightened levels of PDIA3 markers which, when overexpressed in SW480 cells, escalated tumorigenicity and oncogenic behaviors, with a noted decrease upon PD-1 monoclonal antibody intervention. CONCLUSIONS: PDIA3 augments the M2 polarization of tumor-associated macrophages via modulation of the STAT3/PD-1 cascade, thus invigorating the tumorous proliferation and dissemination in colorectal cancer. Such revelations position PDIA3 as an auspicious target for PD-1 blockade therapeutics, offering a promising foundation for rectifying colorectal carcinoma.