Tumor-associated macrophages: Harbingers of aggressiveness in oral squamous cell carcinoma

The Clinical Significance of CD163+ Tumor-Associated Macrophages (TAMs) in Laryngeal Squamous Cell Carcinoma

Background and objective The tumor's microenvironment is currently considered an important indicator of the tumor's prognosis, treatment failure, and recurrence. CD163+ tumor-associated macrophages (TAMs) are a marker of poor prognosis in many types of human cancers. In the present study, the expression of CD163+ TAMs was analyzed in laryngeal squamous cell carcinomas (LSCCs) using immunohistochemistry, and this expression was correlated with the clinical and pathological characteristics of LSCC patients. Materials and methods One commercial human larynx microarray with 80 cases of LSCCs, was used for this study. For comparison with normal laryngeal mucosa, a second microarray carrying normal tissues from all human anatomical sites, including normal laryngeal tissues, was used. Immunohistochemical staining was performed, and the primary antibody was a mouse monoclonal against human CD136. The absence of the primary antibody was used as a negative control. The percentage of positive cells was categorized into five scores: 0 (0%); 1, (1%-10%); 2, (11%-50%); 3, (51%-80%); and 4, (>80%). A case was scored as positive for CD163 with a score >= 1. The χ2 test was used to assess the CD163 expression in LSCC cases (N=80). A statistically significant difference was defined as P 0.05. Results The human larynx microarray containing 80 cases of LSCCs was used for this study. The age of the cancer patients in this array was in the range of 39 to 72, with a median of 53. LSCC grades were distributed as follows: 25 patients were designated as grade I, 43 were designated as grade II, and 6 were designated as grade III. Two tumors' (2/80) cores were missing from the microarray. Six tumors on the microarray did not have a grade designation reported by the manufacturer of the array. The expression of CD163 in normal, benign, unmatched laryngeal tissue was absent. In cancer cases, on the other hand, a significant number of LSCCs had TAMs that were positive for CD163 (87% positive tumors, with an IHC score ranging from 1 to 4, χ2=30.634; p<0.001). The rest of the LSCC cases (10 in total) had negative CD163 expression (score of 0). Conclusion A significant majority of LSCCs were found to have CD163+ TAMs expression using tissue microarrays (TMAs). This expression is positively correlated with the tumor's grade, clinical manifestation, and TNM staging. Morphologic evidence shows that the majority of LSCCs express the highest range of immunohistochemistry (IHC) scores for CD163 protein in the membranes and cytoplasm of their TAMs. This study provides evidence of the clinical significance of CD163+TAMs in LSCCs and proposes further studies to pinpoint the exact role of these cells in LSCC patients.

Phenformin suppresses angiogenesis through the regulation of exosomal microRNA-1246 and microRNA-205 levels derived from oral squamous cell carcinoma cells

Exosomes secreted by cancer cells are important components in the tumor microenvironment, enabling cancer cells to communicate with each other and with noncancerous cells to play important roles in tumor progression and metastasis. Phenformin, a biguanide antidiabetic drug, has been reported to have a strong antitumor function in multiple types of cancer cells, however little research has been reported about whether phenformin can regulate the secretion of exosomes by cancer cells to regulate the tumor microenvironment and contribute to its antitumor function. Here we found that exosomes (Phen-Exo) derived from phenformin-treated oral squamous cell carcinoma (OSCC) cells significantly suppress the proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro. The inhibition of angiogenesis by Phen-Exo was verified in vivo by matrigel plug angiogenesis assays and by chick chorioallantoic membrane assays. Mechanistically, we discovered that the expression of microRNA-1246 (miR-1246) and microRNA-205 (miR-205) was significantly increased in exosomes secreted by OSCC cells treated with phenformin, while high expression levels of miR-1246 or miR-205 in vascular endothelial cells inhibited their angiogenic effects and decreased expression of the angiogenic factor VEGFA. In conclusion, these results reveal that phenformin can inhibit angiogenesis by regulating the levels of miR-1246 and miR-205 in exosomes secreted by OSCC cells, suggesting that phenformin has the potential to alter the tumor microenvironment to antagonize the growth of OSCCs, which provides a theoretical basis for developing new strategies to treat OSCCs in the future.

The Relationship between VEGF-C, TAM, and Lymph Node Metastasis in Oral Cancer

Objective

To investigate the relationship between vascular endothelial growth factor-C (VEGF-C) and tumor-associated macrophages in oral cancer (TAMs) with lymph node metastasis.

Method

From January 2018 to January 2022, 155 cases of oral cancer tissues and 165 cases of normal mucosal tissues were collected from oral surgical resection tissues or biopsy specimens in Hebei Eye Hospital. Oral cancer tissues were observed. The control group had normal mucosal tissues. The clinical and immune parameters were observed and the treatment of oral cancer is also briefly discussed.

Results

The number of TAMs and the expression of VEGF-C in oral cancer tissues were significantly higher than those in normal tissues (P < 0.05). The lymphatic vessel density, the number of TAMs, and the expression of VEGF-C in the metastatic group were higher than in nonmetastatic group, and the lymphatic vessel density, the number of TAMs, and the expression of VEGF-C in the paracancerous tissues were higher than central tumor tissue in the metastatic group (P < 0.05). Univariate analysis showed that the number of TAMs was related to the histological stage and the pathological type of oral cancer (P > 0.05). The expression of VEGF-C was associated with the histological stage of oral cancer (P < 0.05). Compared with the immune function after different treatments, the contents of CD4+ in both groups was higher than before, and the combined treatment group was increased more than single treatment group (P < 0.05). The contents of CD3+ and CD8+ in the two groups were lower than before, and the combined treatment group was decreased higher than combined treatment group (P < 0.05).

Conclusions

The number of TAMs and the expression of VEGF-C in oral cancer tissues are higher than normal tissues. The number of TAMs and the expression of VEGF-C are higher in patients with lymph node metastasis. TAMs and VEGF-C may play an important role in lymph node metastasis of oral cancer. Integrated traditional Chinese and Western medicine can improve the immune function of patients with oral cancer and may improve the therapeutic efficacy.

Role of the Tumor Microenvironment and the Influence of Epigenetics on the Tumor Microenvironment in Oral Carcinogenesis: Potential Implications

Oral cancer has become a significant problem throughout the world, particularly in countries that are still developing. Recent literature supports the contribution of components of the tumor microenvironment (TME) and the effect of epigenetic changes happening in the cells of the TME on oral cancer development and progression. In this review, we comprehensively examine the significance of TME in the development of OC along with the current understanding of the epigenetic modifications that regulate the TME and their cohesive impact on tumor traits and their potential as therapeutic targets.