Fig 2: has_circ_0069313 correlated with Treg infiltration. (A) Samples were collected and subjected to IHC using the CD25 antibody. The representative images were shown with a 200× and 400× magnification. (B) The relative has_circ_0069313 level and CD25 IHC score were collected and regression analysis was applied, R = 0.61, p < 0.001. (C) The graphic illustration of coculture strategy and exosome treatment strategy. (D) Treg cells were treated with OSCC derived exosomes or co-cultured with OSCC. The Treg cells were collected and subjected to qRT-PCR, relative has_circ_0069313 was measured (Student’s two-tailed paired test, ***p < 0.001). (E) Relative miR-325-3p was detected in Treg cells with indicated treatments (Student’s two-tailed paired test, ***p < 0.001). (F) Immunoblot was applied for Foxp3 in Treg cells with indicated treatments.

Fig 3: Collagen concentration regulates the expression levels of Treg biomarkers. (A) Immunofluorescence staining of FOXP3 and CD4 in Jurkat T cells encapsulated in different collagen concentrations. (B) Colocalization analysis of FOXP3 and CD4 in Jurkat T cells encapsulated in 1 mg/ml collagen matrix. (C) Colocalization analysis of FOXP3 and CD4 in Jurkat T cells encapsulated in 3 mg/ml collagen matrix. (D) Colocalization analysis of FOXP3 and CD4 in Jurkat T cells encapsulated in 6 mg/ml collagen matrix. (E) Average fluorescence intensity of FOXP3, CD4 and CD25 among different collagen concentration groups. (F) Percentage of CD4+/FOXP3+ T cells among different collagen concentration groups. (G) Percentage of CD4+/CD25+ T cells among different collagen concentration groups. (scale bar, 50 μm). ns, not significant. **p < 0.01, ***p < 0.001, ****p < 0.0001.