Head and neck squamous cell carcinoma represent a major global health burden, with tongue tumors being the most common subtype. Endoplasmic reticulum (ER) protein 29 (ERp29) is a chaperone protein, encoded by the ERP29 gene on chromosome 12. It is an ER-resident and its main function is the protein folding and trafficking. Although Erp29 has been implicated in tumor biology, its functional role in tongue squamous cell carcinoma (TSCC) remains poorly understood.

To identify microRNA (miRNA) alterations and associated signaling pathways induced by ERP29 silencing in TSCC cells.

SCC-4 TSCC cells (ATCC, CRL-1624) were edited using CRISPR/Cas9 to generate ERP29 knockout clones. miRNA expression was profiled using nCounter® miRNA Expression Assay Kit (NanoString®), normalized to counts-per-million, and analyzed for differential expression versus parental SCC-4 cells. Validated miRNA targets were retrieved from the multiMiR database and subjected to KEGG and Reactome enrichment analyses. All analyses were performed in the R statistical environment.

ERP29 silencing was associated with down-regulation of several miRNAs, including hsa-miR-27b-3p, hsa-miR-30a-5p, hsa-miR-19b-3p, hsa-miR-320e, hsa-miR-378i, and hsa-miR-126-3p, has-miR-1306-5p, has-miR-616-3p (absolute log2 fold-change >8). KEGG analysis revealed strong enrichment of proteoglycans in cancer (hsa05205) and PI3K/AKT signaling (hsa04151), encompassing canonical TSCC drivers such as TP53 (Entrez 7157), PIK3CA (5290), EGFR (1956), HRAS (3265), AKT1 (207), PTEN (5728), and MAPK1/3 (5594/5595). Reactome enrichment highlighted pathways such as signaling by ALK in cancer (HSA-9700206), NOTCH1 signaling (HSA-2644603), and AKT1 E17K activation (HSA-5674400), all related to growth-factor signaling, extracellular matrix remodeling, and immune crosstalk.

These preliminary data from a single TSCC cell line suggest that Erp29 loss could reshape the miRNA landscape and enriches gene networks linked to PI3K/AKT, NOTCH, and proteoglycan-mediated cancer progression. The results are preliminary and require validation in additional cell lines and clinical samples to confirm the role of Erp29 in tumor-host interactions.