Application of metabolomics in oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a prevalent malignancy affecting the head and neck region. The prognosis for OSCC patients remains unfavorable due to the absence of precise and efficient early diagnostic techniques. Metabolomics offers a promising approach for identifying distinct metabolites, thereby facilitating early detection and treatment of OSCC. OBJECTIVE: This review aims to provide a comprehensive overview of recent advancements in metabolic marker identification for early OSCC diagnosis. Additionally, the clinical significance and potential applications of metabolic markers for the management of OSCC are discussed. RESULTS: This review summarizes metabolic changes during the occurrence and development of oral squamous cell carcinoma and reviews prospects for the clinical application of characteristic, differential metabolites in saliva, serum, and OSCC tissue. In this review, the application of metabolomic technology in OSCC research was summarized, and future research directions were proposed. CONCLUSION: Metabolomics, detection technology that is the closest to phenotype, can efficiently identify differential metabolites. Combined with statistical data analyses and artificial intelligence technology, it can rapidly screen characteristic biomarkers for early diagnosis, treatment, and prognosis evaluations.

Oral tongue squamous cell carcinoma diagnosis from tissue metabolic profiling.

OBJECTIVE: Disease metabolomes have been studied for identifying diagnostic and predictive biomarkers of pathology. Oral tongue squamous cell carcinoma (OTSCC) is one of the most prevalent subtypes of head and neck squamous cell carcinoma, yet the profile and diagnostic value of its tissue metabolite are unclear. SUBJECTS AND METHODS: Tumor tissue samples and matched normal mucosal tissue samples were collected from 40 OTSCC patients. Untargeted metabolic analysis by liquid chromatography-mass spectrometry/mass spectrometry, in positive and negative ion modes, was used to identify dysregulated metabolites in OTSCC. Further, utilizing LASSO regression and receiver operating characteristic analyses, biomarker metabolites were selected and validated, and a diagnostic model was established. RESULTS: One hundred and ninety metabolites were detected. The OTSCC had a total of 89 dysregulated metabolites, of which 73 were elevated. A diagnostic panel of nine metabolites was subsequently created that could accurately identify OTSCC with 100% sensitivity of 100%, 100% specificity and an AUC of 1.00. CONCLUSIONS: This study identified distinct metabolic characteristics of OTSCC and established a diagnostic model. Our research also contributes to the investigation of the pathogenesis of OTSCC.

Oral squamous cell carcinoma diagnosed from saliva metabolic profiling.

Saliva is a noninvasive biofluid that can contain metabolite signatures of oral squamous cell carcinoma (OSCC). Conductive polymer spray ionization mass spectrometry (CPSI-MS) is employed to record a wide range of metabolite species within a few seconds, making this technique appealing as a point-of-care method for the early detection of OSCC. Saliva samples from 373 volunteers, 124 who are healthy, 124 who have premalignant lesions, and 125 who are OSCC patients, were collected for discovering and validating dysregulated metabolites and determining altered metabolic pathways. Metabolite markers were reconfirmed at the primary tissue level by desorption electrospray ionization MS imaging (DESI-MSI), demonstrating the reliability of diagnoses based on saliva metabolomics. With the aid of machine learning (ML), OSCC and premalignant lesions can be distinguished from the normal physical condition in real time with an accuracy of 86.7%, on a person by person basis. These results suggest that the combination of CPSI-MS and ML is a feasible tool for accurate, automated diagnosis of OSCC in clinical practice.

Impact of preanalytical freezing delay time on the stability of metabolites in oral squamous cell carcinoma tissue samples.

INTRODUCTION: Metabolite stability is critical for tissue metabolomics. However, changes in metabolites in tissues over time from the operating room to the laboratory remain underexplored. OBJECTIVES: In this study, we evaluated the effect of postoperative freezing delay time on the stability of metabolites in normal and oral squamous cell carcinoma (OSCC) tissues. METHODS: Tumor and paired normal tissues from five OSCC patients were collected after surgical resection, and samples was sequentially quenched in liquid nitrogen at 30, 40, 50, 60, 70, 80, 90 and 120 min (80 samples). Untargeted metabolic analysis by liquid chromatography-mass spectrometry/mass spectrometry in positive and negative ion modes was used to identify metabolic changes associated with delayed freezing time. The trends of metabolite changes at 30-120 and 30-60 min of delayed freezing were analyzed. RESULTS: 190 metabolites in 36 chemical classes were detected. After delayed freezing for 120 min, approximately 20% of the metabolites changed significantly in normal and tumor tissues, and differences in the metabolites were found in normal and tumor tissues. After a delay of 60 min, 29 metabolites had changed significantly in normal tissues, and 84 metabolites had changed significantly in tumor tissues. In addition, we constructed three tissue freezing schemes based on the observed variation trends in the metabolites. CONCLUSION: Delayed freezing of tissue samples has a certain impact on the stability of metabolites. For metabolites with significant changes, we suggest that the freezing time of tissues be reasonably selected according to the freezing schemes and the actual clinical situation.

Plasma membrane proteomics of tumor spheres identify CD166 as a novel marker for cancer stem-like cells in head and neck squamous cell carcinoma.

Patients with advanced head and neck squamous cell carcinoma (HNSCC) have a poor prognosis with the currently available therapy, and tumor recurrence is frequently observed. The discovery of specific membrane-associated cancer stem cell (CSC) markers is crucial for the development of novel therapeutic strategies to target these CSCs. To address this issue, we established sphere cultures to enrich CSCs and used them for plasma membrane proteomics to identify specific membrane signatures of the HNSCC spheres. Of a dataset that included a total of 376 identified proteins, 200 were bona fide membrane proteins. Among them, 123 proteins were at least 1.5-fold up- or down-regulated in the spheres relative to the adherent cultures. These proteins included cell adhesion molecules, receptors, and transporter proteins. Some of them play key roles in wnt, integrin, and TGFß signaling pathways. When we compared our dataset with two published hESC membrane protein signatures, we found 18 proteins common to all three of the databases. CD166 and CD44 were two such proteins. Interestingly, the expression of CD166, rather than that of the well-established HNSCC CSC marker CD44, was significantly related to the malignant behavior of HNSCC. Relative to CD166(low) HNSCC cells, CD166(high) HNSCC cells had a greater sphere-formation ability in vitro and tumor formation ability in vivo. Patients whose tumors expressed high levels of CD166 had a significantly poorer clinical outcome than those whose tumors expressed low levels of CD166 (cohort 1: 96 cases, p = 0.040), whereas the level of CD44 expression had only a marginal influence on the clinical outcome of patients with HNSCC (p = 0.078). The level of CD166 expression in HNSCC tumors was also associated with the tumor recurrence rate (cohort 2: 104 cases, p = 0.016). This study demonstrates that CD166 is a valuable cell surface marker for the enrichment of HNSCC stem cells and that plasma membrane proteomics is a promising biological tool for investigating the membrane proteins of CSCs.

An ectopic meningioma in nasal floor.

OBJECTIVE: Primary ectopic meningioma is a rare tumor and is usually limited to the paravertebral soft tissues. The aim of this study was to assist in the diagnosis and treatment of the tumor. METHODS: A 16-year-old boy presented with a nasal floor mass. The computed tomographic scan suggested a neoplastic mass lesion in the nasal floor region, and primary diagnosis is sebaceous cyst. The patient received a surgical resection, and the histologic examinations showed that the lesion was characterized with spindle cells. Immunohistochemical staining showed that the tumor cells presented intense reactivity for epithelial membrane antigen and vimentin. Histologic examination and immunohistochemical staining confirmed the diagnosis of extracranial ectopic meningioma. RESULTS: The patient received a radical surgical and immediate restoration of adjacent flap, and the patient fully recovered 1 week later. CONCLUSIONS: The case highlights the fact that despite its rarity, ectopic meningioma should be considered as a differential diagnosis of any mass lesion in the head and neck region, especially when spindle cells are histologically observed.

An osteochondroma of the mandibular condyle.

OBJECTIVE: Osteochondroma is rarely seen in the facial region, especially around the condyle. Here, we report a case of condylar osteochondroma, aiming to assist the diagnosis and treatment of the tumor. METHODS: A case of osteochondroma of the left mandibular condyle in a 49-year-old man was presented. Medical records with x-ray, computed tomographic scan, and bone scan of histologically proven osteochondroma of mandibular condyle were obtained. RESULTS: The patient underwent a surgical resection and had fewer functional changes as well as less dysfunction of the temporomandibular joint. CONCLUSIONS: The current study highlights the fact that, despite its rarity in the mandibular condyle, surgical resection is an effective treatment method. The decision, however, depends on how much swing of the mandible is required after surgery for correction of asymmetry and occlusion.

Cross­talk between lymphangiogenesis and malignant melanoma cells: New opinions on tumour drainage and immunization (Review).

Malignant melanoma (MM) is a highly aggressive tumour that can easily metastasize through the lymphatic system at the early stages. Lymph node (LN) involvement and lymphatic vessel (LV) density (LVD) represent a harbinger of an adverse prognosis, indicating a strong link between the state of the lymphatic system and the advancement of MM. Permeable capillary lymphatic vessels are the optimal conduits for melanoma cell (MMC) invasion, and lymphatic endothelial cells (LECs) can also release a variety of chemokines that actively attract MMCs expressing chemokine ligands through a gradient orientation. Moreover, due to the lower oxidative stress environment in the lymph compared with the blood circulation, MMCs are more likely to survive and colonize. The number of LVs surrounding MM is associated with tumour-infiltrating lymphocytes (TILs), which is crucial for the effectiveness of immunotherapy. On the other hand, MMCs can release various endothelial growth factors such as VEGF-C/D-VEGFR3 to mediate LN education and promote lymphangiogenesis. Tumour-derived extracellular vesicles are also used to promote lymphangiogenesis and create a microenvironment that is more conducive to tumour progression. MM is surrounded by a large number of lymphocytes. However, both LECs and MMCs are highly plastic, playing multiple roles in evading immune surveillance. They achieve this by expressing inhibitory ligands or reducing antigen recognition. In recent years, tertiary lymphoid structures have been shown to be associated with response to anti-immune checkpoint therapy, which is often a positive prognostic feature in MM. The present review discusses the interaction between lymphangiogenesis and MM metastasis, and it was concluded that the relationship between LVD and TILs and patient prognosis is analogous to a dynamically tilted scale.

Advanced progress of spatial metabolomics in head and neck cancer research.

Head and neck cancer ranks as the sixth most prevalent malignancy, constituting 5 % of all cancer cases. Its inconspicuous onset often leads to advanced stage diagnoses, prompting the need for early detection to enhance patient prognosis. Currently, research into early diagnostic markers relies predominantly on genomics, proteomics, transcriptomics, and other methods, which, unfortunately, necessitate tumor tissue homogenization, resulting in the loss of temporal and spatial information. Emerging as a recent addition to the omics toolkit, spatial metabolomics stands out. This method conducts in situ mass spectrometry analyses on fresh tissue specimens while effectively preserving their spatiotemporal information. The utilization of spatial metabolomics in life science research offers distinct advantages. This article comprehensively reviews the progress of spatial metabolomics in head and neck cancer research, encompassing insights into cancer cell metabolic reprogramming. Various mass spectrometry imaging techniques, such as secondary ion mass spectrometry, stroma-assisted laser desorption/ionization, and desorption electrospray ionization, enable in situ metabolite analysis for head and neck cancer. Finally, significant emphasis is placed on the application of presently available techniques for early diagnosis, margin assessment, and prognosis of head and neck cancer.

MicroRNA155 in the growth and invasion of salivary adenoid cystic carcinoma.

BACKGROUND: The carcinogenesis mechanism of adenoid cystic carcinoma (ACC) of the salivary gland is poorly understood. MicroRNA155 (miRNA155) has been involved in the carcinogenesis of many malignant tumors. The present study aims to examine the role of miRNA155 in tumor growth and invasion of ACC. METHODS: MiRNA155 expression was determined in ACC specimens along with normal salivary glands by quantitative PCR. Using ACC-2 cells as a model for ACC, cell proliferation was examined by MTT assay after knocking down miRNA155 expression, and cell cycle analysis was performed. Invasive capacity of ACC-2 cells was examined by a Transwell culture assay. The effect of miRNA155 on tumor growth was also examined in vivo using mouse models. The effect of miRNA155 on epidermal growth factor receptor (EGFR)/NF-κB was studied by quantitative PCR and electrophoretic mobility shift assay. RESULTS: MiRNA155 was over-expressed in ACC. Proliferation of ACC-2 cells was markedly inhibited by knocking down miRNA155, resulting from a blockade of cell cycle in the G1 phase. Inhibition of miRNA155 significantly suppressed the invasive capacity of ACC-2 cells. In vivo growth of ACC-2 cell-derived tumors was significantly slower by inhibition of miRNA155. Inhibition of miRNA155 also resulted in decreased expression of EGFR and RelA (NF-κB). CONCLUSION: The results suggest that miRNA155 facilitates cell cycle progression and promotes invasion in ACC and that the EGFR/NF-κB pathway might participate in mediating the effects of miRNA155. This study has provided insights into the carcinogenic mechanisms of ACC and identified new targets for intervention of salivary ACC.

Angiopoietin-2 expression and its relationship with lymphangiogenesis and clinicopathological characteristics in cutaneous malignant melanoma.

Objective: The aim of this study was to investigate angiopoietin-2 (Ang-2/ANGPT2) expression and its relationship with lymphangiogenesis and clinicopathological characteristics in cutaneous malignant melanoma (CMM). Methods: Gene expression differences between metastatic melanoma and melanoma in situ in 472 patients from the TCGA database were analyzed. The target gene Ang-2 was screened. A clinical study was conducted to analyze the correlation between Ang-2 expression in CMM and tumor-associated lymphangiogenesis. A total of 42 patients with primary CMM who underwent extended tumor resection procedures at the Affiliated Hospital of Jiangsu University were included in this study. Clinical data (gender, age, lymph node metastasis, Breslow thickness, and clinical stage) were collected. The expression levels of both Ang-2 and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) proteins were detected by immunohistochemistry (IHC). Lymphatic vascular density (LVD) was counted by using LYVE-1 to label lymphatic endothelial cells (LECs) in peritumoral and intratumoral areas per high-magnification field of view. Statistical analysis was performed using the Pearson correlation test and Student's t-test. Results: Using the TCGA database, it was found that the gene expression level of Ang-2 in 368 cases of metastatic melanoma was significantly higher than that in 104 cases of melanoma in situ. Correlation analysis showed a significant relationship between Ang-2 and LYVE-1, and vascular endothelial growth factor receptor 3(VEGFR3) expression, respectively, in CMM. Moreover, the optimal cutoff value of survival analysis showed that high Ang-2 expression in CMM had a worse prognosis, based on data from the TCGA database. Our research showed that Ang-2 was more highly expressed in the group of patients with lymph node metastasis and in the group of stage 3C-4 patients than in the group of patients with no lymph node metastasis and in the group of stage 0-3B patients. Our research also showed that LVD in the group of patients with lymph node metastasis and in the group of stage 3C-4 patients was significantly higher than that in the group of no lymph node metastasis and in the group of stage 0-3B patients, respectively. Breslow thickness also correlated with Ang-2 expression and LVD. Ang-2 expression was not related to sex or age. Ang-2 expression was obviously correlated with LVD. Conclusion: An evaluation of Ang-2 expression and LVD can be used to predict the risk of tumor lymphatic metastasis and determine the prognosis of CMM. These results may also provide a new clinical treatment strategy for CMM.

Impact of primary molars with periapical disease on permanent successors: A retrospective radiographic study.

Objective: To clarify the effects on the development, position and morphology of the permanent successors of primary molars affected by apical periodontitis (AP). Method: A total of 132 panoramic radiographs of children aged from 4 to 10 were screened out and a total of 159 mandibular second primary molars with chronic apical periodontitis（AP）(93 males and 66 females) were analyzed. The maturation values of permanent successors were interpreted and scored according to Nolla's method and compared with normal ones'. The proportion of abnormalities in the morphology and orientation of permanent successors were counted, and the differences between men and women was analyzed. The distribution of various abnormalities in different age groups was also analyzed. Result: There were significant differences in development of permanent successors in this study compared with the normal ones' in all age groups, among which the differences were statistically significant in males aged in 4,5,7 groups and females aged in 4,6 (P < 0.05). The proportions of permanent successors involved with dental follicle broken, malposition and malformation were 78.94%, 42.1%, 8.42% and 82.50%, 38.75%, 15.00%, respectively, with no gender difference. And the highest proportion of these three were all found in 9 years old age group. Conclusion: AP of primary teeth can lead to accelerated or delayed development of permanent successors to some extent, and may also lead to changes in their shape and direction.

Sebaceous Carcinoma of the Submandibular Gland a Case Report and Review of the Literature.

Objective: Sebaceous carcinoma (SC) of the submandibular gland is extremely rare. Owing to the low morbidity and nonspecific clinical manifestations, diagnosis is commonly delayed, which increases metastasis and mortality. To date, there have been five reported cases of SC of the submandibular gland. Here, we present a new case and review the relevant literature. Methods and Results: A 36-year-old woman presented with an enlarged left submandibular gland. Clinical features included a non-tender solitary nodular mass with normal overlying skin. There were no special findings on computed tomography or ultrasound examination except for a swollen mass in the left submandibular gland. The patient underwent surgical resection. Pathological examination confirmed the diagnosis of SC with nerve infiltration. Immunohistochemical examination of this case showed positive staining for P63, P40, CK7, CK8/18, MLH1, MSH2, MSH6, and PMS2. The specimen was negative for androgen receptor, CEA, S-100, CK5/6, SOX-10, SOX-11, SMA, and GCDFP-15. The KI-67 labeling index was determined to be 15%. PAS and anti-epithelial membrane antigen were positive in partial area. The patient is still undergoing follow-up, and no metastasis or recurrence has been observed for 2 months. Conclusion: This case highlighted the fact that despite its rarity, SC should be considered as a differential diagnosis for masses located in the head and face. Early and accurate diagnosis, followed by wide surgical excision, has a favorable prognosis. Therefore, clinicians should be familiar with the clinical and pathological features of this disease.

Multiperspective quantitative tumor-stroma ratio reveals histological areas associated with poor outcomes in oral squamous cell carcinoma.

AIMS: Different regions of oral squamous cell carcinoma (OSCC) have particular histopathological characteristics, and the individual histological characteristics of the tumors are poorly understood. Therefore, calculating the proportion of tumor cells in different regions that allow assessment of the prognostic outcomes for OSCC patients would be of great clinical significance. METHODS AND RESULTS: We established an open-source software-based analytic pipeline that defines the inner tumor and invasive tumor front (ITF) in pancytokeratin-stained whole slide images (WSIs) and quantifies the tumor-stroma ratio (TSR) within the two regions. We applied this method to 114 patients with OSCC and predicted patient prognosis by the TSR. The proportion of tumor area in the inner tumor was generally higher than that in the ITF (p < 0.0001). TSR was an independent prognostic factor for overall survival (OS) (p = 0.016), disease-free survival (DFS) (p = 0.026), and relapse-free survival (RFS) (p = 0.037) in inner tumor, and TSR was an independent prognostic factor for OS (p = 0.00052), DFS (p = 0.035), and metastasis-free survival (MFS) (p = 0.038) in the ITF. Tumor-low status was associated with poorer prognosis. There was a significant correlation between the TSR and perineural invasion (PNI) in the inner tumor (p = 0.009). CONCLUSIONS: The histopathological characteristics of different regions of OSCC may be used to develop the potential prognostic markers. The TSR of the inner tumor is more targeted in predicting prognosis and accurately assesses the risk of PNI+.

Clinicopathologic features of oral squamous papilloma and papillary squamous cell carcinoma: a study of 197 patients from eastern China.

Oral squamous papilloma and papillary squamous cell carcinoma are 2 clinicopathologically distinctive papillary epithelial tumors. The current study aims to compare the clinical and pathologic features of these oral papillary lesions in a patient population from eastern China. A retrospective review in a series of patients with clinical and pathologic diagnosis of oral squamous papilloma (n = 141) and papillary squamous cell carcinoma (n = 56) was conducted. The average age of oral squamous papilloma was 51.0 years (male-to-female ratio, 1.82), with the palate being the predominant site. The average age of oral papillary squamous cell carcinoma was 63.3 years (male-to-female ratio, 1.67), with the gingiva being the predominant site. Multivariate analysis revealed that the elderly patient with papillary lesion (≥60 years) was associated with 3.09-fold (95% confidence interval, 1.59-6.03) increased carcinoma risk compared with the nonelderly patient. The lesion located on the gingiva was associated with 4.98-fold (95% confidence interval, 1.96-12.63) increased carcinoma risk compared with other oral sites. Collectively, clinicopathologic features of oral squamous papilloma and papillary squamous cell carcinoma in eastern China were elucidated. Elderly patients with oral papillary lesions located on the gingiva correlate with higher carcinoma risk. It highlights the importance of using a histologic examination to confirm the clinical diagnosis for any suspicious papillary lesions.

20 abnormal metabolites of Stage IV Grade C periodontitis was discovered by CPSI-MS.

Saliva is a noninvasive biofluid that contains the metabolic signature of severe periodontitis (SP, Stage IV and Grade C). Conductive polymer spray ionization mass spectrometry (CPSI-MS) was used to record a wide range of metabolites within a few seconds, making this technique a promising point-of-care method for the early detection of SP (Stage IV and Grade C). Saliva samples from 31 volunteers, consisting of 16 healthy controls (HC) and 15 patients with SP (Stage IV and Grade C), were collected to identify dysregulated metabolites. Twenty metabolites were screened out, including seven amino acids. Moreover, the results showed that amino acid metabolism is closely related to the development of periodontitis. The present study further confirmed that salivary metabolites in the oral cavity were significantly altered after plaque removal. These results suggest that the combination of CPSI-MS is a feasible tool for preclinical screening of SP (Stage IV and Grade C).

Identification of Metabolism-Associated Biomarkers for Early and Precise Diagnosis of Oral Squamous Cell Carcinoma.

The 5-year survival rate for oral squamous cell carcinoma (OSCC), one of the most common head and neck cancers, has not improved in the last 20 years. Poor prognosis of OSCC is the result of failure in early and precise diagnosis. Metabolic reprogramming, including the alteration of the uptake and utilisation of glucose, amino acids and lipids, is an important feature of OSCC and can be used to identify its biomarkers for early and precise diagnosis. In this review, we summarise how recent findings of rewired metabolic networks in OSCC have facilitated early and precise diagnosis of OSCC.

Asparagine Synthetase-Mediated l-Asparagine Metabolism Disorder Promotes the Perineural Invasion of Oral Squamous Cell Carcinoma.

Dysregulated amino acids metabolism reciprocally interplays with evolutionary phenotypic characteristics of cancer cells to enhance metastasis. The high metastasis potential of oral squamous cell carcinoma (OSCC) can manifest with perineural invasion (PNI). We here aimed to determine the role of amino acids metabolism in OSCCs with different PNI statuses. Targeted metabolomics was used to quantify 48 amino acids in 20 fresh OSCC samples and 25 amino acids were successfully detected, within which 9 were significantly up-regulated in PNI positive (PNI+) samples. As its highest area under the curve value (0.9063), l-asparagine was selected as the biomarker to distinguish PNI+ from PNI negative (PNI-). Then, the key enzyme of l-asparagine, asparagine synthetase (ASNS), was investigated using immunohistochemistry with 86 OSCC patients. The results showed that ASNS mainly expressed in tumor epitheliums and positively correlated with lymph node metastasis and PNI. Moreover, subgroup survival analysis revealed that ASNS expression combined with PNI status significantly improved their prognostic value, which was confirmed by the TCGA OSCC cohort (n = 279). To validate whether ASNS promotes PNI, we determined ASNS expression levels in five OSCC cell lines and one normal oral keratinocyte, and HSC3 showed the lowest ASNS level but CAL33 had the highest. Therefore, HSC3 and CAL33 (or PBS as control) were selected and injected separately into sciatic nerves to construct the in vivo PNI mouse models. Although both models eventually developed the hind-limb paralysis, nerve dysfunction in the CAL33 model progressed significantly earlier than HSC3 (Day 9 vs. Day 24). Besides, CAL33 migrated significantly farther than HSC3 in the nerve microenvironment (P = 0.0003), indicating high ASNS expression is indispensable for OSCC progression, especially PNI formation, through l-asparagine metabolism alteration. This study provides novel insights into how amino acids metabolism disorders alter tumor neurotropism which helps cancer metastasis.

In situ DESI-MSI lipidomic profiles of mucosal margin of oral squamous cell carcinoma.

BACKGROUND: Although there is consensus that the optimal safe margin is ≥ 5mm, obtaining clear margins (≥5 mm) intraoperatively seems to be the major challenge. We applied a molecular diagnostic method at the lipidomic level to determine the safe surgical resection margin of OSCC by desorption electrospray ionisation mass spectrometry imaging (DESI-MSI). METHODS: By overlaying mass spectrometry images with hematoxylin-eosin staining (H&E) from 18 recruited OSCC participants, the mass spectra of all pixels across the diagnosed tumour and continuous mucosal margin regions were extracted to serve as the training and validation datasets. A Lasso regression model was used to evaluate the test performance. FINDINGS: By leave-one-out validation, the Lasso model achieved 88.6% accuracy in distinguishing between tumour and normal regions. To determine the safe surgical resection distance and margin status of OSCC, a set of 14 lipid ions that gradually decreased from tumour to normal tissue was assigned higher weight coefficients in the Lasso model. The safe surgical resection distance of OSCC was measured using the developed 14 lipid ion molecular diagnostic model for clinical reference. The overall accuracy of predicting tumours, positive margins, and negative margins was 92.6%. INTERPRETATION: The spatial segmentation results based on our diagnostic model not only clearly delineated the tumour and normal tissue, but also distinguished the different status of surgical margins. Meanwhile, the safe surgical resection margin of OSCC on frozen sections can also be accurately measured using the developed diagnostic model. FUNDING: This study was supported by Nanjing Municipal Key Medical Laboratory Constructional Project Funding (since 2016) and the Centre of Nanjing Clinical Medicine Tumour (since 2014).

ITGB2-mediated metabolic switch in CAFs promotes OSCC proliferation by oxidation of NADH in mitochondrial oxidative phosphorylation system.

Objectives: Integrins, the coordinator of extracellular and intracellular signaling, are often found to be aberrant in tumors and can reshape the tumor microenvironment. Although previous studies showed that integrin beta 2 (ITGB2) is important for host defense, its expression profile and role in tumors, especially in cancer associated fibroblasts (CAFs) are still unknown. Methods: Immunofluorescence stain and fluorescence activated cell sorting were used to analyze the ITGB2 expression profile in oral squamous cell carcinoma (OSCC). RT-PCR and western blot were used to compare ITGB2 expression in normal fibroblasts (NFs) and cancer associated fibroblasts (CAFs). Clinical data and function-based experiments were used to investigate the promoting tumor growth ability of ITGB2 expressing CAFs. Enhanced glycolysis activity was identified by using bioinformatics analyses and GC/MS assays. MCT1 knockdown OSCC cell lines were constructed to explore the pro-proliferative mechanisms of ITGB2 expressing CAFs in multiple in vitro and in vivo assays. Results: We found that CAFs exhibited significantly higher ITGB2 expression than the matched NFs. In addition, higher ITGB2 expression in CAFs was correlated with higher TNM stages and more Ki67+ tumor cells, indicating its ability to promote OSCC proliferation. Further, co-culture assay demonstrated that ITGB2-mediated lactate release in CAFs promoted OSCC cell proliferation. Mechanically, ITGB2 regulated PI3K/AKT/mTOR pathways to enhance glycolysis activity in CAFs. Accordingly, lactate derived from ITGB2-expressing CAFs was absorbed and metabolized in OSCC to generate NADH, which was then oxidized in the mitochondrial oxidative phosphorylation system (OXPHOS) to produce ATP. Notably, inhibiting the OXPHOS system with metformin delayed the proliferative capacity of OSCC cells cultured in the ITGB2-expressing CAFs medium. Conclusions: Our study uncovered the ITGB2high pro-tumoral CAFs that activated the PI3K/AKT/mTOR axis to promote tumor proliferation in OSCC by NADH oxidation in the mitochondrial oxidative phosphorylation system.