Effect of the intratumoral microbiota on spatial and cellular heterogeneity in cancer.

The tumour-associated microbiota is an intrinsic component of the tumour microenvironment across human cancer types1,2. Intratumoral host-microbiota studies have so far largely relied on bulk tissue analysis1-3, which obscures the spatial distribution and localized effect of the microbiota within tumours. Here, by applying in situ spatial-profiling technologies4 and single-cell RNA sequencing5 to oral squamous cell carcinoma and colorectal cancer, we reveal spatial, cellular and molecular host-microbe interactions. We adapted 10x Visium spatial transcriptomics to determine the identity and in situ location of intratumoral microbial communities within patient tissues. Using GeoMx digital spatial profiling6, we show that bacterial communities populate microniches that are less vascularized, highly immuno­suppressive and associated with malignant cells with lower levels of Ki-67 as compared to bacteria-negative tumour regions. We developed a single-cell RNA-sequencing method that we name INVADEseq (invasion-adhesion-directed expression sequencing) and, by applying this to patient tumours, identify cell-associated bacteria and the host cells with which they interact, as well as uncovering alterations in transcriptional pathways that are involved in inflammation, metastasis, cell dormancy and DNA repair. Through functional studies, we show that cancer cells that are infected with bacteria invade their surrounding environment as single cells and recruit myeloid cells to bacterial regions. Collectively, our data reveal that the distribution of the microbiota within a tumour is not random; instead, it is highly organized in microniches with immune and epithelial cell functions that promote cancer progression.

Mitochondrial RNA modifications shape metabolic plasticity in metastasis.

Aggressive and metastatic cancers show enhanced metabolic plasticity1, but the precise underlying mechanisms of this remain unclear. Here we show how two NOP2/Sun RNA methyltransferase 3 (NSUN3)-dependent RNA modifications-5-methylcytosine (m5C) and its derivative 5-formylcytosine (f5C) (refs.2-4)-drive the translation of mitochondrial mRNA to power metastasis. Translation of mitochondrially encoded subunits of the oxidative phosphorylation complex depends on the formation of m5C at position 34 in mitochondrial tRNAMet. m5C-deficient human oral cancer cells exhibit increased levels of glycolysis and changes in their mitochondrial function that do not affect cell viability or primary tumour growth in vivo; however, metabolic plasticity is severely impaired as mitochondrial m5C-deficient tumours do not metastasize efficiently. We discovered that CD36-dependent non-dividing, metastasis-initiating tumour cells require mitochondrial m5C to activate invasion and dissemination. Moreover, a mitochondria-driven gene signature in patients with head and neck cancer is predictive for metastasis and disease progression. Finally, we confirm that this metabolic switch that allows the metastasis of tumour cells can be pharmacologically targeted through the inhibition of mitochondrial mRNA translation in vivo. Together, our results reveal that site-specific mitochondrial RNA modifications could be therapeutic targets to combat metastasis.

Oral and non-oral lichen planus show genetic heterogeneity and differential risk for autoimmune disease and oral cancer.

Lichen planus (LP) is a T-cell-mediated inflammatory disease affecting squamous epithelia in many parts of the body, most often the skin and oral mucosa. Cutaneous LP is usually transient and oral LP (OLP) is most often chronic, so we performed a large-scale genetic and epidemiological study of LP to address whether the oral and non-oral subgroups have shared or distinct underlying pathologies and their overlap with autoimmune disease. Using lifelong records covering diagnoses, procedures, and clinic identity from 473,580 individuals in the FinnGen study, genome-wide association analyses were conducted on carefully constructed subcategories of OLP (n = 3,323) and non-oral LP (n = 4,356) and on the combined group. We identified 15 genome-wide significant associations in FinnGen and an additional 12 when meta-analyzed with UKBB (27 independent associations at 25 distinct genomic locations), most of which are shared between oral and non-oral LP. Many associations coincide with known autoimmune disease loci, consistent with the epidemiologic enrichment of LP with hypothyroidism and other autoimmune diseases. Notably, a third of the FinnGen associations demonstrate significant differences between OLP and non-OLP. We also observed a 13.6-fold risk for tongue cancer and an elevated risk for other oral cancers in OLP, in agreement with earlier reports that connect LP with higher cancer incidence. In addition to a large-scale dissection of LP genetics and comorbidities, our study demonstrates the use of comprehensive, multidimensional health registry data to address outstanding clinical questions and reveal underlying biological mechanisms in common but understudied diseases.

Loss of p53 drives neuron reprogramming in head and neck cancer.

The solid tumour microenvironment includes nerve fibres that arise from the peripheral nervous system1,2. Recent work indicates that newly formed adrenergic nerve fibres promote tumour growth, but the origin of these nerves and the mechanism of their inception are unknown1,3. Here, by comparing the transcriptomes of cancer-associated trigeminal sensory neurons with those of endogenous neurons in mouse models of oral cancer, we identified an adrenergic differentiation signature. We show that loss of TP53 leads to adrenergic transdifferentiation of tumour-associated sensory nerves through loss of the microRNA miR-34a. Tumour growth was inhibited by sensory denervation or pharmacological blockade of adrenergic receptors, but not by chemical sympathectomy of pre-existing adrenergic nerves. A retrospective analysis of samples from oral cancer revealed that p53 status was associated with nerve density, which was in turn associated with poor clinical outcomes. This crosstalk between cancer cells and neurons represents mechanism by which tumour-associated neurons are reprogrammed towards an adrenergic phenotype that can stimulate tumour progression, and is a potential target for anticancer therapy.

Tumor Necrosis Factor α-Induced Protein 8-Like 1 Binds to Protein Arginine Methyltransferase 1 to Suppress the Methylation of Signal Transducer and Activator of Transcription 3 and Cell Growth in Oral Squamous Cell Carcinoma.

The tumor necrosis factor α-induced protein 8 (TIPE, also TNFAIP8 or OXi-α) family is a newly discovered series of proteins involved in immune regulation and tumorigenesis. TIPE1, a member of the TIPE/TNFAIP8/OXi-α family, has emerged as an anticancer-drug target, as it promotes cancer cell apoptosis and inhibits cell proliferation. The current study aimed to systematically reveal that TIPE1 regulates the activity of protein arginine methyltransferase (PRMT)-1 and the subsequent methylation of signal transducer and activator of transcription (STAT)-3 to suppress oral squamous cell carcinoma (OSCC) growth. TIPE1 was down-regulated in the OSCC cell lines (Tca8113, SCC25, Cal27, SCC15, and HSC27). TIPE1 overexpression significantly inhibited cell proliferation, colony formation, in vivo tumorgenicity, and Ki-67 expression in OSCC. TIPE1 interacted with the catalytic region of PRMT1 and inhibited STAT3 methylation. The effects of TIPE1 on OSCC cells were alleviated after PRMT1 overexpression, confirming the importance of this interaction to the tumor-suppressive effects of TIPE1. Together, these findings confirmed that TIPE1 mediated PRMT1 suppression through direct binding to its catalytic domain and subsequently inhibited the methylation and expression of STAT3 in OSCC cells, thereby inhibiting cell growth and tumorgenicity.

Interaction of the tumor suppressor SMAD4 and WNT signaling in progression to oral squamous cell carcinoma.

SMAD4 is a tumor suppressor mutated or silenced in multiple cancers, including oral cavity squamous cell carcinoma (OSCC). Human clinical samples and cell lines, mouse models and organoid culture were used to investigate the role that SMAD4 plays in progression from benign disease to invasive OSCC. Human OSCC lost detectable SMAD4 protein within tumor epithelium in 24% of cases, and this loss correlated with worse progression-free survival independent of other major clinical and pathological features. A mouse model engineered for KrasG12D expression in the adult oral epithelium induced benign papillomas, however the combination of KrasG12D with loss of epithelial Smad4 expression resulted in rapid development of invasive carcinoma with features of human OSCC. Examination of regulatory pathways in 3D organoid cultures of SMAD4+ and SMAD4- mouse tumors with Kras mutation found that either loss of SMAD4 or inhibition of TGFß signaling upregulated the WNT pathway and altered the extracellular matrix. The gene signature of the mouse tumor organoids lacking SMAD4 was highly similar to the gene signature of human head and neck squamous cell carcinoma. In summary, this work has uncovered novel mechanisms by which SMAD4 acts as a tumor suppressor in OSCC. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

CLSPN actives Wnt/ß-catenin signaling to facilitate glycolysis and cell proliferation in oral squamous cell carcinoma.

OBJECTIVE: Oral squamous cell carcinoma (OSCC) is a common malignancy with a poor prognosis. This study aimed to determine the influence and underlying mechanisms of CLSPN on OSCC. METHODS: CLSPN expression was tested using quantitative real-time polymerase chain reaction, immunohistochemistry, and western blotting. Flow cytometry, cell counting kit, and colony formation assays were performed to determine OSCC cell apoptosis, viability, and proliferation, respectively. In OSCC cells, the extracellular acidification rate (ECAR), oxygen consumption rate (OCR), glucose uptake, and lactate production were determined using the corresponding kits. Changes in the protein levels of HK2, PKM2, LDHA, Wnt3a, and ß-catenin were assessed using western blotting. RESULTS: CLSPN expression was increased in OSCC tissues. Overexpression of CLSPN in HSC-2 cells promoted cell proliferation, increased the levels of ECAR, glucose uptake, and lactate production, and increased the protein levels of HK2, PKM2, LDHA, Wnt3a, and ß-catenin, but inhibited OCR levels and apoptosis. The knockdown of CLSPN in CAL27 cells resulted in the opposite results. Moreover, the effects of CLSPN overexpression on glycolysis and OSCC cell proliferation were reversed by Wnt3a knockdown. In vivo, knockdown of CLSPN restrained tumor growth, glycolysis, and the activation of Wnt/ß-catenin signaling. CONCLUSION: CLSPN promoted glycolysis and OSCC cell proliferation, and reduced apoptosis, which was achieved by the activation of Wnt/ß-catenin signaling pathway.

FAM122A functions as a tumor suppressor in oral squamous cell carcinoma.

Family with sequence similarity 122a (FAM122A), identified as an endogenous inhibitor of protein phosphatase 2A (PP2A) previously, is involved in multiple important physiological processes, and essential for the growth of acute myeloid leukemia and hepatocellular carcinoma cells. However, the function of FAM122A in oral squamous cell carcinoma (OSCC) is undetermined. In this study, by analyzing TCGA and GEO databases, we found that the expression of FAM122A was significantly down-regulated in head and neck squamous cell carcinoma and OSCC patients, meanwhile this low expression was tightly associated with the poor prognosis and advanced clinical stage during OSCC development. The similar low expression pattern of FAM122A could also been seen in OSCC cell lines compared with normal human oral keratinocytes. Further, we demonstrated that FAM122A knockdown significantly promoted the growth, clonogenic potential as well as migration capabilities of OSCC cells, while these alterations could be rescued by the re-expression of FAM122A. Over-expression of FAM122A suppressed OSCC cell proliferation and migration. FAM122A also inhibited the epithelial-mesenchymal transition (EMT) in OSCC cells by the up-regulation of epithelial marker E-cadherin and down-regulation of mesenchymal markers Fibronectin and Vimentin, which is presumably mediated by transforming growth factor ß receptor 3 (TGFBR3), a novel tumor suppressor. In addition, FAM122A could induce T cell infiltration in OSCC, indicating that FAM122A might influence the immune cell activity of tumor environment and further interfere the tumor development. Collectively, our results suggest that FAM122A functions as a tumor suppressor in OSCC and possibly acts as a predictive biomarker for the diagnosis and/or treatment of OSCC.

EphA2 promotes the transcription of KLF4 to facilitate stemness in oral squamous cell carcinoma.

Ephrin receptor A2 (EphA2), a member of the Ephrin receptor family, is closely related to the progression of oral squamous cell carcinoma (OSCC). Cancer stem cells (CSCs) play essential roles in OSCC development and occurrence. The underlying mechanisms between EphA2 and CSCs, however, are not yet fully understood. Here, we found that EphA2 was overexpressed in OSCC tissues and was associated with poor prognosis. Knockdown of EphA2 dampened the CSC phenotype and the tumour-initiating frequency of OSCC cells. Crucially, the effects of EphA2 on the CSC phenotype relied on KLF4, a key transcription factor for CSCs. Mechanistically, EphA2 activated the ERK signalling pathway, promoting the nuclear translocation of YAP. Subsequently, YAP was bound to TEAD3, leading to the transcription of KLF4. Overall, our findings revealed that EphA2 can enhance the stemness of OSCC cells, and this study identified the EphA2/KLF4 axis as a potential target for treating OSCC.

Portable, handheld, and affordable blood perfusion imager for screening of subsurface cancer in resource-limited settings.

Precise information on localized variations in blood circulation holds the key for noninvasive diagnostics and therapeutic assessment of various forms of cancer. While thermal imaging by itself may provide significant insights on the combined implications of the relevant physiological parameters, viz. local blood perfusion and metabolic balance due to active tumors as well as the ambient conditions, knowledge of the tissue surface temperature alone may be somewhat inadequate in distinguishing between some ambiguous manifestations of precancer and cancerous lesions, resulting in compromise of the selectivity in detection. This, along with the lack of availability of a user-friendly and inexpensive portable device for thermal-image acquisition, blood perfusion mapping, and data integration acts as a deterrent against the emergence of an inexpensive, contact-free, and accurate in situ screening and diagnostic approach for cancer detection and management. Circumventing these constraints, here we report a portable noninvasive blood perfusion imager augmented with machine learning-based quantitative analytics for screening precancerous and cancerous traits in oral lesions, by probing the localized alterations in microcirculation. With a proven overall sensitivity >96.66% and specificity of 100% as compared to gold-standard biopsy-based tests, the method successfully classified oral cancer and precancer in a resource-limited clinical setting in a double-blinded patient trial and exhibited favorable predictive capabilities considering other complementary modes of medical image analysis as well. The method holds further potential to achieve contrast-free, accurate, and low-cost diagnosis of abnormal microvascular physiology and other clinically vulnerable conditions, when interpreted along with complementary clinically evidenced decision-making perspectives.

TLR9 activation induces immunosuppression and tumorigenesis via PARP1/PD-L1 signaling pathway in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, and metastasis and immunosuppression are responsible for the poor prognosis of OSCC. Previous studies have shown that poly(ADP-ribose) polymerase (PARP)1 plays a key role in the pathogenesis of OSCC. Therefore, PARP1 may serve as an important research target for the potential treatment of OSCC. Here, we aimed to investigate the role of PARP1 in the tumorigenesis of OSCC and elucidate the key molecular mechanisms of its upstream and downstream regulation in vivo and in vitro. In human OSCC tissues and cells, Toll-like receptor (TLR)9 and PD-L1 were highly expressed and PARP1 was lowly expressed. Suppression of TLR9 remarkably repressed CAL27 and SCC9 cell proliferation, migration, and invasion. After coculture, we found that low expression of TLR9 inhibited PD-L1 expression and immune escape. In addition, TLR9 regulated PD-L1 expression through the PARP1/STAT3 pathway. PARP1 mediated the effects of TLR9 on OSCC cell proliferation, migration, and invasion and immune escape. Additionally, in vivo experiments further verified that TLR9 promoted tumor growth and immune escape by inhibiting PARP1. Collectively, TLR9 activation induced immunosuppression and tumorigenesis via PARP1/PD-L1 signaling pathway in OSCC, providing important insights for subsequent in-depth exploration of the mechanism of OSCC.NEW & NOTEWORTHY In this research, we took PARP1 as the key target to explore its regulatory effect on oral squamous cell carcinoma (OSCC). The key molecular mechanisms involved in its upstream and downstream regulation were elucidated in OSCC cell lines in vitro and tumor-bearing mice in vivo, combined with clinical OSCC tissues.

Mapping Conformational Changes in the Saliva Proteome Potentially Associated with Oral Cancer Aggressiveness.

Diverse proteomics-based strategies have been applied to saliva to quantitatively identify diagnostic and prognostic targets for oral cancer. Considering that these targets may be regulated by events that do not imply variation in protein abundance levels, we hypothesized that changes in protein conformation can be associated with diagnosis and prognosis, revealing biological processes and novel targets of clinical relevance. For this, we employed limited proteolysis-mass spectrometry in saliva samples to explore structural alterations, comparing the proteome of healthy control and oral squamous cell carcinoma (OSCC) patients with and without lymph node metastasis. Thirty-six proteins with potential structural rearrangements were associated with clinical patient features including transketolase and its interacting partners. Moreover, N-glycosylated peptides contribute to structural rearrangements of potential diagnostic and prognostic markers. Altogether, this approach utilizes saliva proteins to search for targets for diagnosing and prognosing oral cancer and can guide the discovery of potential regulated sites beyond protein-level abundance.

Growth modulatory effects of fenretinide encompass keratinocyte terminal differentiation: a favorable outcome for oral squamous cell carcinoma chemoprevention.

Oral squamous cell carcinoma (OSCC) is worldwide health problem associated with high morbidity and mortality. From both the patient and socioeconomic perspectives, prevention of progression of premalignant oral intraepithelial neoplasia (OIN) to OSCC is clearly the preferable outcome. Optimal OSCC chemopreventives possess a variety of attributes including high tolerability, bioavailability, efficacy and preservation of an intact surface epithelium. Terminal differentiation, which directs oral keratinocytes leave the proliferative pool to form protective cornified envelopes, preserves the protective epithelial barrier while concurrently eliminating growth-aberrant keratinocytes. This study employed human premalignant oral keratinocytes and an OSCC cell line to evaluate the differentiation-inducing capacity of the synthetic retinoid, fenretinide (4HPR). Full-thickness oral mucosal explants were evaluated for proof of concept differentiation studies. Results of this study characterize the ability of 4HPR to fulfill all requisite components for keratinocyte differentiation, i.e. nuclear import via binding to cellular RA binding protein-II (molecular modeling), binding to and subsequent activation of retinoic acid nuclear receptors (receptor activation assays), increased expression and translation of genes associated with keratinocyte differentiation [Reverse transcription polymerase chain reaction (RT-PCR), immunoblotting] upregulation of a transglutaminase enzyme essential for cornified envelope formation (transglutaminase 3, functional assay) and augmentation of terminal differentiation in human oral epithelial explants (image-analyses quantified corneocyte desquamation). These data build upon the chemoprevention repertoire of 4HPR that includes function as a small molecule kinase inhibitor and inhibition of essential mechanisms necessary for basement membrane invasion. An upcoming clinical trial, which will assess whether a 4HPR-releasing mucoadhesive patch induces histologic, clinical and molecular regression in OIN lesions, will provide essential clinical insights.

Potential role of epithelial-mesenchymal transition induced by periodontal pathogens in oral cancer.

With the increasing incidence of oral cancer in the world, it has become a hotspot to explore the pathogenesis and prevention of oral cancer. It has been proved there is a strong link between periodontal pathogens and oral cancer. However, the specific molecular and cellular pathogenic mechanisms remain to be further elucidated. Emerging evidence suggests that periodontal pathogens-induced epithelial-mesenchymal transition (EMT) is closely related to the progression of oral cancer. Cells undergoing EMT showed increased motility, aggressiveness and stemness, which provide a pro-tumour environment and promote malignant metastasis of oral cancer. Plenty of studies proposed periodontal pathogens promote carcinogenesis via EMT. In the current review, we discussed the association between the development of oral cancer and periodontal pathogens, and summarized various mechanisms of EMT caused by periodontal pathogens, which are supposed to play an important role in oral cancer, to provide targets for future research in the fight against oral cancer.

Hellebrigenin induces oral cancer cell apoptosis by modulating MAPK signalling and XIAP expression.

Oral squamous cell carcinoma (OSCC), which accounts for 90% of all oral cancers, has become a public health crisis worldwide. despite advances in therapeutic interventions, the prognosis remains poor for advanced-stage OSCC. In this study, we investigate the anticancer activity and the mode of action of hellebrigenin in human OSCC. The findings demonstrated that hellebrigenin exerted cytotoxic effects in OSCC cells through cell cycle arrest at the G2/M phase and downregulation of cell cycle-related proteins (cyclins A2, B1 and D3, Cdc2, CDK4 and CDK6). Moreover, hellebrigenin caused activation of PARP and caspase 3, 8 and 9, followed by downregulation of antiapoptotic proteins (Bcl-2 and Bcl-xL) and upregulation of pro-apoptotic proteins (Bax and Bak). The hellebrigenin treatment also increased Fas, DR5, DcR2 and DcR3 expressions in oral cancer cells, indicating the compound causes oral cancer cell apoptosis through both intrinsic and extrinsic pathways. Regarding upstream signalling, hellebrigenin was found to reduce the phosphorylation of ERK, p38, and JNK, indicating that hellebrigenin triggers caspase-mediated apoptosis by downregulating MAPK signalling pathway. Finally, the human apoptosis array findings revealed that hellebrigenin specifically suppressed the expression of XIAP to execute its pro-apoptotic activities. Taken together, the study suggests that hellebrigenin can act as a potent anticancer compound in human OSCC.

Hypomethylation-associated Sox11 upregulation promotes oncogenesis via the PI3K/AKT pathway in OLP-associated OSCC.

Oral lichen planus (OLP) is a particularly prevalent oral disorder with the potential to progress to oral squamous cell carcinoma (OSCC). SRY-box transcription factor 11 (Sox11) has been reported to serve as a prognostic marker for various cancers. However, the role and mechanism of Sox11 in OLP-related OSCC are unknown. Our results indicated that Sox11 was highly expressed, and that Sox11 promoter methylation was significantly reduced in OLP-associated OSCC tissues. High Sox11 expression and Sox11 promoter hypomethylation indicate a poor patient prognosis. According to in vivo and in vitro experiments, the knockdown of Sox11 inhibited proliferation, invasion, and migration while driving its apoptotic death in OSSC cells; Sox11 overexpression exerted the opposite effect as Sox11 knockdown. Mechanistically, knockdown of Sox11 inhibited PI3K/AKT and glycolysis pathway, and overexpression of Sox11 enhanced the PI3K/AKT and glycolysis pathways in OSCC cells. In addition, we demonstrated that Sox11 overexpression accelerated the progression of OSCC, at least in part by promoting PI3K/AKT pathway activation. In conclusion, our data indicated that the DNA hypomethylation-associated upregulation of Sox11 could promote oncogenic transformation via the PI3K/AKT pathway in OLP-associated OSCC. Therefore, Sox11 might be a reliable biomarker for predicting the progression of precancerous oral tissues.

2α, 3α, 24-Thrihydroxyurs-12-en-24-ursolic acid enhances the cytotoxic effect of cisplatin on oral cancer cells by down-regulating autophagy.

This study aimed to investigate the effect and mechanism of 2α, 3α, 24-thrihydroxyurs-12-en-24-ursolic acid (TEOA) alone or in combination with cisplatin on oral cancer. TEOA, a pentacyclic triterpenoid compound isolated from the roots of Actinidia eriantha, has demonstrated antitumor activity in preclinical experiments. However, its role in oral cancer remains poorly understood. Our findings revealed that a low concentration of TEOA did not exhibit significant cytotoxicity against oral squamous cell carcinoma cells. However, when combined with cisplatin, TEOA showed a significant therapeutic effect. The combined treatments resulted in a significant inhibition of proliferation and migration and a significant increase in apoptosis of squamous cell carcinoma cells. Cisplatin exposure increased autophagy levels, which may contribute to chemoresistance. Of note, the presence of TEOA significantly inhibited cisplatin-induced autophagy, leading to improved chemotherapy efficacy. Our findings indicate that a mild low dosage of TEOA may enhance the cytotoxic effect of cisplatin by downregulating autophagy in oral cancer cells.

DNMT1-targeting remodeling global DNA hypomethylation for enhanced tumor suppression and circumvented toxicity in oral squamous cell carcinoma.

BACKGROUND: The faithful maintenance of DNA methylation homeostasis indispensably requires DNA methyltransferase 1 (DNMT1) in cancer progression. We previously identified DNMT1 as a potential candidate target for oral squamous cell carcinoma (OSCC). However, how the DNMT1- associated global DNA methylation is exploited to regulate OSCC remains unclear. METHODS: The shRNA-specific DNMT1 knockdown was employed to target DNMT1 on oral cancer cells in vitro, as was the use of DNMT1 inhibitors. A xenografted OSCC mouse model was established to determine the effect on tumor suppression. High-throughput microarrays of DNA methylation, bulk and single-cell RNA sequencing analysis, multiplex immunohistochemistry, functional sphere formation and protein immunoblotting were utilized to explore the molecular mechanism involved. Analysis of human samples revealed associations between DNMT1 expression, global DNA methylation and collaborative molecular signaling with oral malignant transformation. RESULTS: We investigated DNMT1 expression boosted steadily during oral malignant transformation in human samples, and its inhibition considerably minimized the tumorigenicity in vitro and in a xenografted OSCC model. DNMT1 overexpression was accompanied by the accumulation of cancer-specific DNA hypomethylation during oral carcinogenesis; conversely, DNMT1 knockdown caused atypically extensive genome-wide DNA hypomethylation in cancer cells and xenografted tumors. This novel DNMT1-remodeled DNA hypomethylation pattern hampered the dual activation of PI3K-AKT and CDK2-Rb and inactivated GSK3ß collaboratively. When treating OSCC mice, targeting DNMT1 achieved greater anticancer efficacy than the PI3K inhibitor, and reduced the toxicity of blood glucose changes caused by the PI3K inhibitor or combination of PI3K and CDK inhibitors as well as adverse insulin feedback. CONCLUSIONS: Targeting DNMT1 remodels a novel global DNA hypomethylation pattern to facilitate anticancer efficacy and minimize potential toxic effects via balanced signaling synergia. Our study suggests DNMT1 is a crucial gatekeeper regarding OSCC destiny and treatment outcome.

The interaction of PRDX1 with Cofilin promotes oral squamous cell carcinoma metastasis.

Peroxiredoxin 1 (PRDX1) is an important member of the peroxiredoxin family (PRDX) and is upregulated in a variety of tumors. Previous studies have found that high PRDX1 expression is closely related to the metastasis of oral squamous cell carcinoma (OSCC), but the specific molecular mechanism is elusive. To elucidate the role of PRDX1 in the metastasis process of OSCC, we evaluated the expression of PRDX1 in OSCC clinical specimens and its impact on the prognosis of OSCC patients. Then, the effect of PRDX1 on OSCC metastasis and cytoskeletal reconstruction was explored in vitro and in nude mouse tongue cancer models, and the molecular mechanisms were also investigated. PRDX1 can directly interact with the actin-binding protein Cofilin, inhibiting the phosphorylation of its Ser3 site, accelerating the depolymerization and turnover of actin, promoting OSCC cell movement, and aggravating the invasion and metastasis of OSCC. In clinical samples and mouse tongue cancer models, PRDX1 also increased lymph node metastasis of OSCC and was negatively correlated with the phosphorylation of Cofilin; PRDX1 also reduced the overall survival rate of OSCC patients. In summary, our study identified that PRDX1 may be a potential therapeutic target to inhibit OSCC metastasis.