Stromal cells in the tumor microenvironment (TME) closely interact with tumor cells and affect tumor cell behavior in diverse manners. We herein investigated the mechanisms by which cancer-associated fibroblasts (CAFs) affect the functional polarization of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC) in vitro and in human cancer samples. The expression of CD68, CD14, CD163, CD200R, CD206, HLA-G, CD80, and CD86 was higher in CD14-positive cells co-cultured with the culture supernatants of CAFs established from OSCC specimens (CAF-educated cells) than in control cells. The gene expression level of ARG1, IL10, and TGFB1 was increased in CAF-educated cells. CAF-educated cells suppressed T cell proliferation more strongly than control cells, and the neutralization of TGF-β IL-10, or arginase I significantly restored T cell proliferation. We then investigated the relationship between the infiltration of CAFs and TAMs using tissue samples obtained from patients with OSCC. The infiltration of CAFs was associated with the numbers of CD68-positive and CD163-positive macrophages. It also correlated with lymphatic invasion, vascular invasion, lymph node involvement, and the TNM stage. The infiltration of CAFs was identified as an independent prognostic factor in OSCC. Our results indicate that CAFs play important roles in shaping the tumor immunosuppressive microenvironment in OSCC by inducing the protumoral phenotype of TAMs. Therapeutic strategies to reverse CAF-mediated immunosuppression need to be considered.

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Background:Amino-acid transporters are necessary for the tumour cell growth and survival, and have a crucial role in the development and invasiveness of cancer cells. But, it remains unclear about the prognostic significance of L-type amino-acid transporter 1 (LAT1), system ASC amino-acid transporter-2 (ASCT2), and xCT expression in patients with tongue cancer. We conducted the clinicopathological study to investigate the protein expression of these amino-acid transporters in tongue cancer.Methods:Eighty-five patients with surgically resected tongue cancer were evaluated. Tumour sections were stained by immunohistochemistry for LAT1, ASCT2, xCT, 4F2hc/CD98hc (4F2hc), Ki-67, and microvessel density (MVD) determined by CD34, and p53.Results:L-type amino-acid transporter 1 and 4F2hc were highly expressed in 61% (52 out of 85) and 45% (38 out of 47), respectively. ASC amino-acid transporter-2 and xCT were positively expressed in 59% (50 out of 85) and 21% (18 out of 85), respectively. The expression of both LAT1 and ASCT2 was significantly associated with disease staging, lymph-node metastasis, lymphatic permeation, 4F2hc expression and cell proliferation (Ki-67). xCT expression indicated a significant association with advanced stage and tumour factor. By univariate analysis, disease staging, lymphatic permeation, vascular invasion, LAT1, ASCT2, 4F2hc, and Ki-67 had a significant relationship with overall survival. Multivariate analysis confirmed that LAT1 was an independent prognostic factor for predicting poor prognosis.Conclusions:L-type amino-acid transporter 1 and ASCT2 can serve as a significant prognostic factor for predicting worse outcome after surgical treatment and may have an important role in the development and aggressiveness of tongue cancer.

PURPOSE This study aimed to compare patients with early oral cavity squamous cell carcinoma (OCSCC) (tumor category [T] 1-2, node-negative, and no distant metastasis) treated with traditional elective neck dissection (ND) with those managed by sentinel lymph node biopsy (SLNB) using survival and neck function and complications as end points. METHODS Sixteen institutions in Japan participated in the study (trial registration number: UMIN000006510). Patients of age ≥ 18 years with histologically confirmed, previously untreated OCSCC (Union for International Cancer Control TNM Classification of Malignant Tumors 7th edition T1-2, node-negative no distant metastasis), with ≥ 4 mm (T1) depth of invasion, were randomly assigned to undergo standard selective ND (ND group; n = 137) or SLNB-navigated ND (SLNB group; n = 134). The primary end point was the 3-year overall survival rate, with a 12% noninferiority margin; secondary end points included postoperative neck functionality and complications and 3-year disease-free survival. Sentinel lymph nodes underwent intraoperative multislice frozen section analyses for the diagnosis. Patients with positive sentinel lymph nodes underwent either one-stage or second-look ND. RESULTS Pathologic metastasis-positive nodes were observed in 24.8% (34 of 137) and 33.6% (46 of 134) of patients in the ND and SLNB groups, respectively ( P = .190). The 3-year overall survival in the SLNB group (87.9%; lower limit of one-sided 95% CI, 82.4) was noninferior to that in the ND group (86.6%; lower limit 95% CI, 80.9; P for noninferiority < .001). The 3-year disease-free survival rate was 78.7% (lower limit 95% CI, 72.1) and 81.3% (75.0) in the SLNB and ND groups, respectively ( P for noninferiority < .001). The scores of neck functionality in the SLNB group were significantly better than those in the ND group. CONCLUSION SLNB-navigated ND may replace elective ND without a survival disadvantage and reduce postoperative neck disability in patients with early-stage OCSCC.

Cancer-associated fibroblasts (CAFs) have been shown to play an important role in angiogenesis, invasion, and metastasis. In the present study, we determined whether CAFs within the tumor microenvironment (TME) in head and neck squamous cell carcinoma (HNSCC) contributed to promoting immunosuppression and evasion from immune surveillance. Six pairs of CAFs and normal fibroblasts (NFs) were established from the resected tumor tissues of patients with HNSCC. The effects of CAFs and NFs on the functions of T cells were comparatively analyzed. CAFs expressed the co-regulatory molecules, B7H1 and B7DC, whereas NFs did not. The expression levels of cytokine genes, including those for IL6, CXCL8, TNF, TGFB1, and VEGFA, were higher in CAFs. T cell proliferation was suppressed more by CAFs or their supernatants than by NFs. Moreover, PBMCs co-cultured with the supernatants of CAFs preferentially induced T cell apoptosis and regulatory T cells over those co-cultured with the supernatants of NFs. A microarray analysis revealed that the level of genes related to the leukocyte extravasation and paxillin signaling pathways was higher in CAFs than in NFs. These results demonstrated that CAFs collaborated with tumor cells in the TME to establish an immunosuppressive network that facilitated tumor evasion from immunological destruction.