NR2F1 contributes to cancer cell dormancy, invasion and metastasis of salivary adenoid cystic carcinoma by activating CXCL12/CXCR4 pathway.

BACKGROUND: Salivary adenoid cystic carcinoma (SACC) can recur after removal of the primary tumor and treatment, where they can keep no clinical symptoms and dormant state for 10-15 years. NR2F1 has been demonstrated to regulate the tumor cell dormancy in various malignant tumors and has a potential impact on recurrence and metastasis of carcinoma. However, the role and significance of NR2F1 in SACC dormancy still remain unknown. METHODS: A total number of 59 patients with a diagnosis of SACC were included to detected expression of NR2F1, Ki-67 by immunohistochemical (IHC) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick and labeling (TUNEL). Fisher's exact test was used to examine the NR2F1 expression and clinicopathologic parameters of SACC. In vitro, SACC cell lines were transfected NR2F1 and knockdown NR2F1 respectively. CCK-8, flow cytometry, wound healing assay and transwell invasion determined SACC cell proliferation, apoptosis, cell cycle, migration and invasion respectively. Chromatin immunoprecipitation (ChIP) assays were utilized to demonstrate the potential role of NR2F1 in SACC invasion via CXCL12/CXCR4 axis. In vivo, xenografts of nude mice via subcutaneous injection or tail vein injection were used to testify the results in vitro. RESULTS: Among the 59 patients with SACC, 23.73% (14/59) were positive to NR2F1 expression, a lower rate of expression compared with 60% (6/10) in normal salivary gland samples. NR2F1 was correlated with metastasis, relapse and dormancy of SACC. SACC cells with transfected NR2F1 remained dormant, as well as enhanced invasion and metastasis. Knockdown of NR2F1 via siRNA after NR2F1 overexpression restored the proliferation and the cell number in G2/M phases, and reduced the abilities of migration and invasion. In addition, NR2F1 promoted the expression of CXCL12 and CXCR4, and overexpression of CXCL12 at least partly rescued the proliferation, migration, and invasion activities induced by NR2F1 silencing. CONCLUSIONS: NR2F1 may be an underlying mechanism of SACC recurrence and metastasis via regulating tumor cell dormancy through CXCL12/CXCR4 pathway.

[Basaloid squamous cell carcinoma in gingiva: a case report].

As an aggressive subtype of squamous cell carcinoma, basaloid squamous cell carcinoma (BSCC) rarely occurs in the oral and maxillofacial region. The gingiva is an unusual site of BSCC. This study reported a 78-year-old male who presented with left maxillary pain. Clinical examination revealed a gingival mass in the left maxilla. Under microscope, the lesion showed typical comedo necrosis and peripheral palisading. Areas of glandular-like structures were also observed. Immunohistochemistry results revealed that the Ki-67 score of BSCC in this case was 28%, and S-100 was positive in some areas. However, P16 and CK7 were negative. Finally, a diagnosis of BSCC was made based on the pathological and immunohistochemical characteristics. The patient underwent subtotal maxillectomy. After 12 months later, the patient was alive with no evidence of disease. Combined with relevant literature, this article analyzed the clinicopathological features, differential diagnosis, diagnosis, treatment, and prognosis of BSCC. Although surgery remains the main treatment in the head and neck region, radiation-chemotherapy should be considered in some human papilloma virus-positive cases.

Myeloid derived suppressor cells contribute to the malignant progression of oral squamous cell carcinoma.

PURPOSE: The tumor-related myeloid derived suppressor cells (MDSCs), important immunosuppressive cells in tumor microenvironment, play an important role in the cancer progression. This study is aimed to investigate the crosstalk between MDSCs and oral squamous cell carcinoma (OSCC) cells and their role in the malignant progression of OSCC. METHODS: Immunochemistry (IHC) was used to investigate the expression of CD33 in 200 OSCC, 36 premalignant. CD33+ MDSCs were sorted and enriched via magnetic-activated cell sorting (MACS) from OSCC patients or health donor, and their phenotypes were identified by flow cytometry. With a co-culture system of MDSCs and OSCC, the effects of MDSCs on OSCC proliferation, apoptosis, migration invasion, epithelial-mesenchymal transition (EMT), and vasculogenic mimicry formation (VM) formation were assessed, respectively. Besides, peripheral blood mononuclear cells (PBMCs) from health donor were cultured with OSCC supernatant, the level of MDSCs and expressions of Arginase (Arg-1) and inducible nitric oxide synthase (iNOS) were measured. RESULTS: The number of MDSCs was increased in tumor tissues of OSCC patients, and was positively related to the T stage, pathological grade, lymph node metastasis and poor prognosis. Tumor-related MDSCs of the co-culture system promoted OSCC progression by contributing to cell proliferation, migration and invasion as well as inducing EMT and VM. In turn, OSCC cells had potential to induce MDSCs differentiation from PBMCs and increase the expression of Arg-1 and iNOS. CONCLUSION: These indicated that the crosstalk between MDSCs and tumor cells facilitated the malignant progression of OSCC cells and the immune suppressive properties of MDSCs, which may provide new insights into tumor treatment on targeting tumor-associated immunosuppressive cells.

Hypoxia promotes vasculogenic mimicry formation by vascular endothelial growth factor A mediating epithelial-mesenchymal transition in salivary adenoid cystic carcinoma.

OBJECTIVES: To investigate the role of hypoxia in vasculogenic mimicry (VM) of salivary adenoid cystic carcinoma (SACC) and the underlying mechanism involved. MATERIALS AND METHODS: Firstly, wound healing, transwell invasion, immunofluorescence and tube formation assays were performed to measure the effect of hypoxia on migration, invasion, EMT and VM of SACC cells, respectively. Then, immunofluorescence and RT-PCR were used to detect the effect of hypoxia on VE-cadherin and VEGFA expression. And pro-vasculogenic mimicry effect of VEGFA was investigated by confocal laser scanning microscopy and Western blot. Moreover, the levels of E-cadherin, N-cadherin, Vimentin, CD44 and ALDH1 were determined by Western blot and immunofluorescence in SACC cells treated by exogenous VEGFA or bevacizumab. Finally, CD31/ PAS staining was performed to observe VM and immunohistochemistry was used to determine the levels of VEGFA and HIF-1α in 95 SACC patients. The relationships between VM and clinicopathological variables, VEGFA or HIF-1α level were analysed. RESULTS: Hypoxia promoted cell migration, invasion, EMT and VM formation, and enhanced VE-cadherin and VEGFA expression in SACC cells. Further, exogenous VEGFA markedly increased the levels of N-cadherin, Vimentin, CD44 and ALDH1, and inhibited the expression of E-cadherin, while the VEGFA inhibitor reversed these changes. In addition, VM channels existed in 25 of 95 SACC samples, and there was a strong positive correlation between VM and clinic stage, distant metastases, VEGFA and HIF-1α expression. CONCLUSIONS: VEGFA played an important role in hypoxia-induced VM through regulating EMT and stemness, which may eventually fuel the migration and invasion of SACC.