Localization of Fusobacterium nucleatum in oral squamous cell carcinoma and its possible directly interacting protein molecules: A case series.

INTRODUCTION: While 15 to 20% of cancers are associated with microbial infection, the relationship between oral microorganisms and oral squamous cell carcinoma (OSCC) remains unclear. The location of bacteria in a tumor is closely related to its carcinogenic mechanism. The aim of this study was to analyse bacterial diversity in clinical OSCC tissue samples and tumor distant normal tissues, locate target bacteria, and search for proteins that may interact with target bacteria. MATERIALS AND METHODS: The 16S rDNA method was used to analyse bacterial diversity in clinical OSCC tissue samples and tumor distant normal tissues. Correlations between Fusobacterium abundance and clinicopathological characteristics were analysed using the χ2 test. The position of target bacteria was analysed by fluorescence in situ hybridization (FISH), and the expression of CK, CD31, CD45, CD68, cyclin D1, ß-catenin, E-cadherin, NF-κB, and HIF-1α was analysed by immunohistochemistry (IHC) in OSCC tumor tissues and tumor distant normal tissues. RESULTS: The 16S rDNA results showed that the detected amount of Fusobacterium in OSCC tumor tissues was significantly larger than that in tumor distant normal tissues. High expression of Fusobacterium was significantly correlated with the lifestyle-related oral risk habits, including smoking (p=0.036) and alcohol consumption (p=0.022), but did not correlate with patient sex, age, tumor laterality, tumor size, grade or TNM stage. Fusobacterium nucleatum was enriched in tumor stroma, where CD31+ blood vessels and inflammatory cells (including CD45+ leukocytes and CD68+ macrophages) were densely distributed. Cyclin D1 was mainly expressed in the nucleus of tumor cells. ß-catenin was expressed in the tumor cell membrane and was positively expressed in tumor interstitial vascular endothelial cells. E-cadherin was mainly expressed in tumor cell membranes. NF-κB was positively expressed in the cytoplasm of tumor cells, tumor interstitial cells and myo-fibrocytes. HIF-1α was mainly expressed in the cytoplasm of tumor interstitial cells. HIF-1α was highly expressed where Fusobacterium nucleatum was densely distributed. CONCLUSION: According to our study, the detected amount of Fusobacterium in OSCC tumor tissues was significantly larger than that in tumor distant normal tissues, and Fusobacterium nucleatum might aggravate inflammation and hypoxia by interacting with NF-κB and HIF-1α in OSCC.

Temporospatial Expression of Neuropeptide Substance P in Dental Pulp Stem Cells During Odontoblastic Differentiation in Vitro and Reparative Dentinogenesis in Vivo.

INTRODUCTION: Substance P (SP) is a neuropeptide released from the nervous fibers in response to injury. In addition to its association with pain and reactions to anxiety and stress, SP exerts various physiological functions by binding to the neurokinin-1 receptor (NK1R). However, the expression and role of SP in reparative dentinogenesis remain elusive. Here, we explored whether SP is involved in odontoblastic differentiation during reparative dentinogenesis. METHODS: Dental pulp stem cells (DPSCs) were isolated from healthy human dental pulp tissues and subjected to odontoblastic differentiation. The expression of SP and NK1R during odontoblastic differentiation was investigated in vitro. The effects of SP on odontoblastic differentiation of DPSCs were evaluated using alizarin red staining, alkaline phosphatase staining, and real-time polymerase chain reaction. After direct pulp capping with mineral trioxide aggregate, the expression of SP and NK1R during reparative dentin formation in rats were identified using histological and immunohistochemical staining. RESULTS: SP and NK1R expression increased during the odontoblastic differentiation of DPSCs. SP translocated to the nucleus when DPSCs were exposed to differentiation medium. NK1R was always present in the nuclei of DPSCs and odontoblast-like cells. Additionally, we discovered that 10-8 M SP marginally enhanced the odontoblastic differentiation of DPSCs, and that these effects could be impaired by the NK1R antagonist. Furthermore, SP and NK1R were expressed in odontoblast-like and dental pulp cells during reparative dentin formation in vivo. CONCLUSIONS: SP contributes to odontoblastic differentiation during reparative dentin formation by binding to the NK1R.

Protein overexpression of toll-like receptor 4 and myeloid differentiation factor 88 in oral squamous cell carcinoma and clinical significance.

Oral squamous cell carcinoma (OSCC) is the most common type of malignancy of the head and neck. In the present study, the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) was evaluated in 55 OSCC tissues and their corresponding adjacent tissues using immunohistochemistry and reverse-transcription quantitative PCR. The results indicated that TLR4 and MyD88 were overexpressed in OSCC. Furthermore, high expression of MyD88 was negatively associated with a poor degree of differentiation, recurrence and metastasis of the tumor and was positively associated with underlying disease, including hypertension, heart disease and diabetes mellitus. Furthermore, high expression of TLR4 was positively associated with a long growth time of the tumor. In conclusion, the present study evaluated the expression levels of TLR4 and MyD88 in OSCC, as well as the association between them and clinicopathological factors, to provide markers for the prognosis and treatment of OSCC. These two genes may serve as biomarkers to optimize OSCC treatment, setting a new direction for stratifying patients and developing precise and personalized treatment regimens; the TLR4/MyD88 pathway may serve as a potential therapeutic target in the future.