BACKGROUND: Oral squamous cell carcinoma (OSCC) is a prevalent type of cancer with a high mortality rate in its late stages. One of the major challenges in OSCC treatment is the resistance to epidermal growth factor receptor (EGFR) inhibitors. Therefore, it is imperative to elucidate the mechanism underlying drug resistance and develop appropriate precision therapy strategies to enhance clinical efficacy. METHODS: To evaluate the efficacy of the combination of the Ca 2+ /calmodulin-dependent protein kinase II (CAMK2) inhibitor KN93 and EGFR inhibitors, we performed in vitro and in vivo experiments using two FAT atypical cadherin 1 ( FAT1 )-deficient (SCC9 and SCC25) and two FAT1 wild-type (SCC47 and HN12) OSCC cell lines. We assessed the effects of EGFR inhibitors (afatinib or cetuximab), KN93, or their combination on the malignant phenotype of OSCC in vivo and in vitro . The alterations in protein expression levels of members of the EGFR signaling pathway and SRY-box transcription factor 2 (SOX2) were analyzed. Changes in the yes-associated protein 1 (YAP1) protein were characterized. Moreover, we analyzed mitochondrial dysfunction. Besides, the effects of combination therapy on mitochondrial dynamics were also evaluated. RESULTS: OSCC with FAT1 mutations exhibited resistance to EGFR inhibitors treatment. The combination of KN93 and EGFR inhibitors significantly inhibited the proliferation, survival, and migration of FAT1 -mutated OSCC cells and suppressed tumor growth in vivo . Mechanistically, combination therapy enhanced the therapeutic sensitivity of FAT1 -mutated OSCC cells to EGFR inhibitors by modulating the EGFR pathway and downregulated tumor stemness-related proteins. Furthermore, combination therapy induced reactive oxygen species (ROS)-mediated mitochondrial dysfunction and disrupted mitochondrial dynamics, ultimately resulting in tumor suppression. CONCLUSION Combination therapy with EGFR inhibitors and KN93 could be a novel precision therapeutic strategy and a potential clinical solution for EGFR-resistant OSCC patients with FAT1 mutations.
Humans ; ErbB Receptors/metabolism* ; Mouth Neoplasms/metabolism* ; Cell Line, Tumor ; Animals ; Drug Resistance, Neoplasm/genetics* ; Cadherins/metabolism* ; Carcinoma, Squamous Cell/metabolism* ; Mice ; Mutation/genetics* ; Mice, Nude ; Protein Kinase Inhibitors/therapeutic use* ; Cetuximab/pharmacology* ; Afatinib/therapeutic use* ; Cell Proliferation/drug effects* ; Signal Transduction/drug effects*

OBJECTIVE: To explore the function of LIM and calponin homology domains 1 (LIMCH1) in the development and progression of oral squamous cell carcinoma (OSCC), along with their potential clinical applications. METHODS: By utilizing transcriptome sequencing data from two groups of oral squamous cell carcinoma patients, along with bioinformatics analytical techniques such as Gene Ontology (GO) and gene co-expression networks, we identified genes that might play a pivotal role in the pathogenesis of oral squamous cell carcinoma. We employed real-time quantitative PCR and Western blotting to validate the expression patterns of these genes across twelve patient tissue samples. Furthermore, we conducted CCK-8 assays, flow cytometry analyses, and scratch wound healing assays to assess the impact of key genes on the biological behaviors of both the Cal27 oral squamous cell carcinoma cell line and the potentially malignant DOK oral lesion cell line. Additionally, we examined correlations between these key genes and clinical disease parameters in 214 oral squamous cell carcinoma patients using The Cancer Genome Atlas (TCGA) data; gene set enrichment analysis (GSEA) analysis results were also incorporated to enhance our findings from real-time quantitative PCR and Western blotting regarding potential mechanisms underlying the action of these key genes. RESULTS: The integrated analysis of sequencing data and bioinformatics revealed that LIMCH1 exhibited significantly reduced mRNA (P < 0.001) and protein levels (P < 0.01) in the oral squamous cell carcinoma tissues compared with normal control tissues. In the Cal27 cells, the low LIMCH1 level group demonstrated a larger wound healing area within 24 hours than the control group (P < 0.01), enhanced proliferation capacity over 72 hours relative to the control group (P < 0.01), and an increased apoptosis rate within 24 hours compared with the high expression group (P < 0.05). However, no significant differences were observed between the low and high level groups in DOK cells. Furthermore, it was determined that low LIMCH1 level correlated with poor prognosis in the patients (P=0.013) and a higher lymph node metastasis rate (P < 0.05). Investigations into the potential mechanisms of action indicated that LIMCH1 did not influence the onset or progression of oral squamous cell carcinoma via the epithelial-mesenchymal transition pathway. CONCLUSION LIMCH1 level may function as a promising biomarker to aid in the prognostic assessment of oral squamous cell carcinoma; however, its precise mechanistic role requires further investigation.
Humans ; Mouth Neoplasms/metabolism* ; Prognosis ; Carcinoma, Squamous Cell/metabolism* ; Biomarkers, Tumor/metabolism* ; LIM Domain Proteins/metabolism* ; Cell Line, Tumor ; Cell Proliferation ; Male ; Female

OBJECTIVE: To investigate the effects of LncRNA SNHG20 on epithelial mesenchymal transition (EMT) and microtubule formation in human oral squamous cell carcinoma (OSCC) cells through targeted regulation of the miR-520c-3p/RAB22A pathway. METHODS: After real-time fluorescence quantitative detection of LncRNA SNHG20, miR-520c-3p, RAB22A mRNA expression levels in OSCC tissues and cells, dual luciferase reporter assay was used to detect the relationship between the three. OSCC cells were randomly separated into control group, sh-NC group, sh-SNHG20 group, sh-SNHG20+anti NC group, and sh-SNHG20+anti miR-520c-3p group. Western blotting was used to detect the expression of N-cadherin, vimentin, and E-cadherin proteins in the OSCC cells. The morphology of HSC-3 cells was observed under microscope. Changes in the number of microtubules formed were detected. The effect of LncRNA SNHG20 on the growth of OSCC tumors and the expression levels of LncRNA SNHG20, miR-520c-3p and RAB22 A in the transplanted tumors were detected by nude mice tumorigenesis experiment. RESULTS: LncRNA SNHG20 and RAB22A mRNA were upregulated in the OSCC tissues and cells, while miR-520c-3p was downregulated (P < 0.05). There were binding sites between LncRNA SNHG20 and miR-520c-3p, RAB22A and miR-520c-3p, which had targeted regulation relationship. Compared with the sh-NC group, the sh-SNHG20 group had fewer stromal like cells, more epithelial like cells, incomplete microtubule structure, and fewer nodules. LncRNA SNHG20, RAB22A, N-Cadherin, and vimentin were downregulated, while miR-520c-3p and E-cadherin were upregulated (P < 0.05). Compared with the sh-SNHG20+anti-NC group, the sh-SNHG20+anti-miR-520c-3p group had a higher number of stromal like cells, a lower number of epithelioid cells, tighter microtubule arrangement, and more microtubule nodules. miR-520c-3p and E-cadherin were downregulated, while RAB22A, N-cadherin, and vimentin were upregulated (P < 0.05). The transplanted tumor of OSCC in sh-SNHG20 group was smaller and lower than that in sh-NC group. The expression levels of LncRNA SNHG20 and RAB22A in the transplanted tumor tissues were lower than those in sh-NC group, and the expression level of miR-520c-3p was higher than that in sh-NC group (P < 0.05). CONCLUSION LncRNA SNHG20 promotes epithelial-mesenchymal transition and microtubule formation in human oral squamous cell carcinoma cells by targeting the miR-520c-3p/RAB22A pathway. Inhibiting the expression of LncRNA SNHG20 can target and regulate the miR-520c-3p/RAB22A pathway to inhibit EMT and microtubule formation in OSCC cells.
Humans ; RNA, Long Noncoding/genetics* ; MicroRNAs/metabolism* ; rab GTP-Binding Proteins/metabolism* ; Epithelial-Mesenchymal Transition/genetics* ; Cell Line, Tumor ; Carcinoma, Squamous Cell/metabolism* ; Animals ; Microtubules/metabolism* ; Mouth Neoplasms/genetics* ; Mice, Nude ; Mice ; Gene Expression Regulation, Neoplastic ; Mice, Inbred BALB C

Perineural invasion (PNI) by tumor cells is a key phenotype of highly-invasive oral squamous cell carcinoma (OSCC). Since Schwann cells (SCs) and fibroblasts maintain the physiological homeostasis of the peripheral nervous system, and we have focused on cancer-associated fibroblasts (CAFs) for decades, it's imperative to elucidate the impact of CAFs on SCs in PNI⁺ OSCCs. We describe a disease progression-driven shift of PNI^- towards PNI⁺ during the progression of early-stage OSCC (31%, n = 125) to late-stage OSCC (53%, n = 97), characterized by abundant CAFs and nerve demyelination. CAFs inhibited SC proliferation/migration and reduced neurotrophic factors and myelin in vitro, and this involved up-regulated ER stress and decreased MAPK signals. Moreover, CAFs also aggravated the paralysis of the hind limb and PNI in vivo. Unexpectedly, leukemia inhibitory factor (LIF) was exclusively expressed on CAFs and up-regulated in metastatic OSCC. The LIF inhibitor EC330 restored CAF-induced SC inactivation. Thus, OSCC-derived CAFs inactivate SCs to aggravate nerve injury and PNI development.
Schwann Cells/metabolism* ; Mouth Neoplasms/metabolism* ; Humans ; Cancer-Associated Fibroblasts/metabolism* ; Animals ; Carcinoma, Squamous Cell/metabolism* ; Neoplasm Invasiveness/pathology* ; Male ; Female ; Mice ; Cell Movement/physiology* ; Cell Proliferation/physiology* ; Cell Line, Tumor ; Leukemia Inhibitory Factor/metabolism* ; Middle Aged

Oral squamous cell carcinoma (OSCC) is the most common manifestation of oral cancer. It has been proposed that periodontal pathogens contribute to OSCC progression, mainly by their virulence factors. However, the main periodontal pathogen and its mechanism to modulate OSCC cells remains not fully understood. In this study we investigate the main host-pathogen pathways in OSCC by computational proteomics and the mechanism behind cancer progression by the oral microbiome. The main host-pathogen pathways were analyzed in the secretome of biopsies from patients with OSCC and healthy controls by mass spectrometry. Then, functional assays were performed to evaluate the host-pathogen pathways highlighted in oral cancer. Host proteins associated with LPS response, cell migration/adhesion, and metabolism of amino acids were significantly upregulated in the human cancer proteome, whereas the complement cascade was downregulated in malignant samples. Then, the microbiome analysis revealed large number and variety of peptides from Fusobacterium nucleatum (F. nucleatum) in OSCC samples, from which several enzymes from the L-glutamate degradation pathway were found, indicating that L-glutamate from cancer cells is used as an energy source, and catabolized into butyrate by the bacteria. In fact, we observed that F. nucleatum modulates the cystine/glutamate antiporter in an OSCC cell line by increasing SLC7A11 expression, promoting L-glutamate efflux and favoring bacterial infection. Finally, our results showed that F. nucleatum and its metabolic derivates promote tumor spheroids growth, spheroids-derived cell detachment, epithelial-mesenchymal transition and Galectin-9 upregulation. Altogether, F. nucleatum promotes pro-tumoral mechanism in oral cancer.
Humans ; Fusobacterium nucleatum/metabolism* ; Mouth Neoplasms/metabolism* ; Disease Progression ; Proteomics ; Carcinoma, Squamous Cell/metabolism* ; Host-Pathogen Interactions ; Metabolic Networks and Pathways ; Case-Control Studies ; Mass Spectrometry

Cancer stem cells (CSCs) are widely acknowledged as primary mediators to the initiation and progression of tumors. The association between microbial infection and cancer stemness has garnered considerable scholarly interest in recent years. Porphyromonas gingivalis (P. gingivalis) is increasingly considered to be closely related to the development of oral squamous cell carcinoma (OSCC). Nevertheless, the role of P. gingivalis in the stemness of OSCC cells remains uncertain. Herein, we showed that P. gingivalis was positively correlated with CSC markers expression in human OSCC specimens, promoted the stemness and tumorigenicity of OSCC cells, and enhanced tumor formation in nude mice. Mechanistically, P. gingivalis increased lipid synthesis in OSCC cells by upregulating the expression of stearoyl-CoA desaturase 1 (SCD1) expression, a key enzyme involved in lipid metabolism, which ultimately resulted in enhanced acquisition of stemness. Moreover, SCD1 suppression attenuated P. gingivalis-induced stemness of OSCC cells, including CSCs markers expression, sphere formation ability, chemoresistance, and tumor growth, in OSCC cells both in vitro and in vivo. Additionally, upregulation of SCD1 in P. gingivalis-infected OSCC cells was associated with the expression of KLF5, and that was modulated by P. gingivalis-activated NOD1 signaling. Taken together, these findings highlight the importance of SCD1-dependent lipid synthesis in P. gingivalis-induced stemness acquisition in OSCC cells, suggest that the NOD1/KLF5 axis may play a key role in regulating SCD1 expression and provide a molecular basis for targeting SCD1 as a new option for attenuating OSCC cells stemness.
Porphyromonas gingivalis/pathogenicity* ; Stearoyl-CoA Desaturase/metabolism* ; Humans ; Carcinoma, Squamous Cell/pathology* ; Mouth Neoplasms/metabolism* ; Animals ; Neoplastic Stem Cells/microbiology* ; Mice, Nude ; Mice ; Nod1 Signaling Adaptor Protein/metabolism* ; Kruppel-Like Transcription Factors/metabolism* ; Cell Line, Tumor

Oral squamous cell carcinoma (OSCC) progresses from preneoplastic precursors via genetic and epigenetic alterations. Previous studies have focused on the treatment of terminally developed OSCC. However, the role of epigenetic regulators as therapeutic targets during the transition from preneoplastic precursors to OSCC has not been well studied. Our study identified lysine-specific demethylase 1 (LSD1) as a crucial promoter of OSCC, demonstrating that its knockout or pharmacological inhibition in mice reversed OSCC preneoplasia. LSD1 inhibition by SP2509 disrupted cell cycle, reduced immunosuppression, and enhanced CD4+ and CD8+ T-cell infiltration. In a feline model of spontaneous OSCC, a clinical LSD1 inhibitor (Seclidemstat or SP2577) was found to be safe and effectively inhibit the STAT3 network. Mechanistic studies revealed that LSD1 drives OSCC progression through STAT3 signaling, which is regulated by phosphorylation of the cell cycle mediator CDK7 and immunosuppressive CTLA4. Notably, LSD1 inhibition reduced the phosphorylation of CDK7 at Tyr170 and eIF4B at Ser422, offering insights into a novel mechanism by which LSD1 regulates the preneoplastic-to-OSCC transition. This study provides a deeper understanding of OSCC progression and highlights LSD1 as a potential therapeutic target for controlling OSCC progression from preneoplastic lesions.
STAT3 Transcription Factor/metabolism* ; Animals ; Histone Demethylases/genetics* ; Phosphorylation ; Mouth Neoplasms/immunology* ; Mice ; Carcinoma, Squamous Cell/immunology* ; Disease Progression ; Cyclin-Dependent Kinase-Activating Kinase ; Precancerous Conditions/metabolism* ; Humans ; Cyclin-Dependent Kinases/metabolism* ; Disease Models, Animal

Hypoxia and aberrant activation of epidermal growth factor receptor (EGFR) are considered important features of various malignancies. However, whether hypoxia can directly trigger EGFR activation and its clinical implications remain unclear. In this study, we demonstrated that in oral cancer, a typical hypoxic tumor, hypoxia can induce chronic but constitutive phosphorylation of wild-type EGFR in the absence of ligands. Oral cancer cell lines exhibit different EGFR phosphorylation responses to hypoxia. In hypoxic HN4 and HN6 cells, ubiquitination-mediated endocytosis, lysosomal sorting, and degradation lead to low levels of EGFR phosphorylation. However, in CAL-27 and HN30 cells, a novel HIF-1α-induced long noncoding RNA (lncRNA), EUDAL, can compete with the E3 ligase/adaptor complex c-Cbl/Grb2 for binding to EGFR, stabilizing phosphorylated EGFR (pEGFR) and resulting in sustained activation of EGFR and its downstream STAT3/BNIP3 signaling. STAT3/BNIP3-mediated autophagy leads to antitumor drug resistance. A high EUDAL/EGFR/STAT3/autophagy pathway activation predicts poor response to chemotherapy in oral cancer patients. Collectively, hypoxia can induce noncanonical ligand-independent EGFR phosphorylation. High EUDAL expression facilitates sustained EGFR phosphorylation in hypoxic tumor cells and leads to autophagy-related drug resistance.
Humans ; ErbB Receptors/metabolism* ; Mouth Neoplasms/pathology* ; RNA, Long Noncoding/genetics* ; Drug Resistance, Neoplasm/genetics* ; Cell Line, Tumor ; Phosphorylation ; Signal Transduction ; STAT3 Transcription Factor/metabolism* ; Cell Hypoxia ; Autophagy ; Proto-Oncogene Proteins c-cbl/metabolism*

OBJECTIVES: This study aimed to explore the expression of lysosomal-associated membrane protein 5 (LAMP5) and microRNA (miR)-302a-3p in oral squamous cell carcinoma (OSCC) and their functional mechanism on the invasion and metastasis of OSCC. METHODS: The expression of LAMP5 in OSCC and its sensitivity as a prognostic indicator were analyzed on the basis of The Cancer Genome Atlas database. Western blot, quantitative reverse transcription polymerase chain reaction, and cell immunocytochemistry were used to detect the expression of LAMP5 in OSCC tissues and cells. The effect of LAMP5 on the proliferation, migration, and invasion of OSCC cells was evaluated through cell counting kit-8, immunocytochemistry, migration, and invasion assays, respectively. The miRNA targeting prediction websites were used to predict the miR that regulates LAMP5 and verify the targeted regulatory effect of miR-302a-3p on LAMP5. The effect of LAMP5 knockdown on OSCC tumor growth was evaluated in a nude mouse tumorigenesis model. RESULTS: LAMP5 was highly expressed in OSCC tissues and cells. It showed high sensitivity in the early diagnosis of OSCC. LAMP5 knockdown significantly inhibited the proliferation, migration, and invasion of OSCC cells, whereas LAMP5 overexpression increased these cell activities. The expression of LAMP5 was regulated by miR-302a-3p. In vivo, LAMP5 knockdown significantly inhibited the growth of OSCC tumor. CONCLUSIONS LAMP5 promotes the malignant progression of OSCC by enhancing the proliferation, migration, and invasion of OSCC cells. The expression of LAMP5 is negatively regulated by miR-302a-3p.
MicroRNAs/metabolism* ; Mouth Neoplasms/metabolism* ; Humans ; Animals ; Carcinoma, Squamous Cell/genetics* ; Neoplasm Invasiveness ; Cell Proliferation ; Mice, Nude ; Cell Movement ; Lysosomal Membrane Proteins/genetics* ; Mice ; Cell Line, Tumor ; Neoplasm Metastasis

Tumor progression is closely related to tumor tissue metabolism and reshaping of the microenvironment. Oral squamous cell carcinoma (OSCC), a representative hypoxic tumor, has a heterogeneous internal metabolic environment. To clarify the relationship between different metabolic regions and the tumor immune microenvironment (TME) in OSCC, Single cell (SC) and spatial transcriptomics (ST) sequencing of OSCC tissues were performed. The proportion of TME in the ST data was obtained through SPOTlight deconvolution using SC and GSE103322 data. The metabolic activity of each spot was calculated using scMetabolism, and k-means clustering was used to classify all spots into hyper-, normal-, or hypometabolic regions. CD4T cell infiltration and TGF-β expression is higher in the hypermetabolic regions than in the others. Through CellPhoneDB and NicheNet cell-cell communication analysis, it was found that in the hypermetabolic region, fibroblasts can utilize the lactate produced by glycolysis of epithelial cells to transform into inflammatory cancer-associated fibroblasts (iCAFs), and the increased expression of HIF1A in iCAFs promotes the transcriptional expression of CXCL12. The secretion of CXCL12 recruits regulatory T cells (Tregs), leading to Treg infiltration and increased TGF-β secretion in the microenvironment and promotes the formation of a tumor immunosuppressive microenvironment. This study delineates the coordinate work axis of epithelial cells-iCAFs-Tregs in OSCC using SC, ST and TCGA bulk data, and highlights potential targets for therapy.
Humans ; Carcinoma, Squamous Cell/metabolism* ; Squamous Cell Carcinoma of Head and Neck ; Mouth Neoplasms/metabolism* ; Immunosuppression Therapy ; Transforming Growth Factor beta ; Head and Neck Neoplasms ; Gene Expression Profiling ; Tumor Microenvironment