Apoptosis Of Oral Squamous Cell Carcinoma Cells Research Articles

METTL3 Promotes OSCC Progression by Down-Regulating WEE1 in a m6A-YTHDF2-Dependent Manner.

Oral squamous cell carcinoma (OSCC) is a common and highly lethal epithelial cancer. This study aimed to confirm the role of METTL3 in promoting OSCC and investigate its specific underlying mechanisms. Expression of the METTL3, YTH domain-containing family 2 (YTHDF2), and WEE1 were examined in normal oral epithelial cells and OSCC cells. Cell functions were examined after overexpressing WEE1 in OSCC cells. MeRIP-qPCR analysis was used to detect WEE1 m6A levels in HOK, SCC25, and CAL27 cells. WEE1 and its m6A levels were evaluated in OSCC cells by knocking down METTL3/YTHDF2, assessing the interaction between METTL3/YTHDF2 and WEE1. The impact of METTL3 and YTHDF2 downregulation on WEE1 mRNA stability was also investigated. The tumor weight and volume in a nude mouse model of OSCC after overexpression of WEE1 and YTHDF2 were measured. Expression of Ki-67 and WEE1 in OSCC tissue was detected using immunohistochemistry. Compared to normal oral epithelial cells, METTL3 and YTHDF2 were upregulated in OSCC cells, while WEE1 was downregulated, and there was a negative correlation between WEE1 and METTL3/YTHDF2 expression. WEE1 overexpression inhibited proliferation, invasion, and migration while promoting apoptosis in OSCC cells. METTL3 and YTHDF2 bound to WEE1 mRNA. METTL3/YTHDF2 knockdown increased WEE1 levels and WEE1 mRNA stability. METTL3 inhibition reduced WEE1 m6A levels. Inhibition of METTL3 weakened the interaction between YTHDF2 and WEE1 mRNA. In vivo, overexpression of WEE1 suppressed OSCC development, which was reversed by overexpression of YTHDF2. METTL3 facilitates the progression of OSCC through m6A-YTHDF2-dependent downregulation of WEE1.

The antitumor effects of herbal medicine Triphala on oral cancer by inactivating PI3K/Akt signaling pathway: based on the network pharmacology, molecular docking, in vitro and in vivo experimental validation

BackgroundThis research aimed to investigate the anti-tumor effects and underlying genetic mechanisms of herbal medicine Triphala (TRP) in oral squamous cell carcinoma (OSCC). MethodsThe target genes of Triphala (TRP) in oral squamous cell carcinoma (OSCC) were identified, and subsequent functional enrichment analysis was conducted to determine the enriched signaling pathways. Based on these genes, a protein-protein interaction network was constructed to identify the top 10 genes with the highest degree. Genes deregulated in OSCC tumor samples were identified to be hub genes among the top 10 genes. In vitro experiments were performed to investigate the influence of TRP extracts on the cell metabolic activity, migration, invasion, apoptosis, and proliferation of two OSCC cell lines (CAL-27 and SCC-9). The functional rescue assay was conducted to investigate the effect of applying the inhibitor and activator of an enriched pathway on the phenotypes of cancer cells. In addition, the zebrafish xenograft tumor model was established to investigate the influence of TRP extracts on tumor growth and metastasis in vivo. ResultsThe target genes of TRP in OSCC were prominently enriched in the PI3K-Akt signaling pathway, with the identification of five hub genes (JUN, EGFR, ESR1, RELA, and AKT1). TRP extracts significantly inhibited cell metabolic activity, migration, invasion, and proliferation and promoted cell apoptosis in OSCC cells. Notably, the application of TRP extracts exhibited the capacity to downregulate mRNA and phosphorylated protein levels of AKT1 and ESR1, while concomitantly inducing upregulation of mRNA and phosphorylated protein levels in the remaining three hub genes (EGFR, JUN, and RELA). The functional rescue assay demonstrated that the co-administration of TRP and the PI3K activator 740Y-P effectively reversed the impact of TRP on the phenotypes of OSCC cells. Conversely, the combination of TRP and the PI3K inhibitor LY294002 further enhanced the effect of TRP on the phenotypes of OSCC cells. Remarkably, treatment with TRP in zebrafish xenograft models demonstrated a significant reduction in both tumor growth and metastatic spread. ConclusionsTriphala exerted significant inhibitory effects on cell metabolic activity, migration, invasion, and proliferation in OSCC cell lines, accompanied by the induction of apoptosis, which was mediated through the inactivation of the PI3K/Akt pathway.

Plumbagin Induces Reactive Oxygen Species and Endoplasmic Reticulum Stress-related Cell Apoptosis in Human Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC), a major malignancy in Taiwan, is an invasive epithelial neoplasm resulting in a low survival rate. Current treatments do not prevent OSCC progression, and antitumor therapies should be improved. Plumbagin, a natural compound extracted from Plumbago zeylanica L., appears to have antitumor effects in various tumors. The antitumor mechanism of plumbagin in OSCC is still unclear. This study investigated the molecular mechanism through which plumbagin induces apoptosis. To investigate the antiproliferative and pro-apoptotic effects of Plumbagin on OSCC cells and explore its underlying mechanism, cell counting kit-8, cell cycle analysis, and annexin V/PI assay were conducted. The functions of plumbagin on endoplasmic reticulum (ER) stress, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) deficiency were analyzed using flow cytometric analysis. Plumbagin-induced apoptosis-associated proteins were detected using western blotting. Plumbagin induced apoptosis in OSCC cells by suppressing tumor cell proliferation through ROS production, ER stress, mitochondrial dysfunction, and caspases activation. Plumbagin is a promising antitumor candidate targeting human OSCC.

Imatinib inhibits oral squamous cell carcinoma by suppressing the PI3K/AKT/mTOR signaling pathway.

Oral squamous cell carcinoma (OSCC) is a prevalent oral and maxillofacial cancer with high mortality as OSCC cells readily invade tissues and metastasize to cervical lymph nodes. Although imatinib exhibits potential anticancer and remarkable clinical activities that therapeutically affect several cancer types, its specific impact on OSCC has yet to be fully explored. Therefore, this study investigated the potential anticancer effect of imatinib on OSCC cells and the underlying mechanisms. The Cell Counting Kit-8 was used to determine the impact of imatinib on cell viability. Then, morphological cell proliferation analysis was conducted to examine how imatinib impacted OSCC cell growth. Moreover, OSCC cell migration was determined through wound-healing assays, and colony formation abilities were investigated through the soft agar assay. Lastly, the effect of imatinib on OSCC cell apoptosis was verified with flow cytometry, and its inhibitory mechanism was confirmed through Western blot. Our results demonstrate that imatinib effectively inhibited OSCC cell proliferation and significantly curtailed OSCC cell viability in a time- and concentration-dependent manner. Furthermore, imatinib suppressed migration and colony formation while promoting OSCC cell apoptosis by enhancing p53, Bax, and PARP expression levels and reducing Bcl-2 expression. Imatinib also inhibited the PI3K/AKT/mTOR signaling pathway and induced OSCC cell apoptosis, demonstrating the potential of imatinib as a treatment for oral cancer.

Bromodomain-containing protein 4 inhibition improves the efficacy of cisplatin and radiotherapy in oral squamous cell carcinoma by suppressing programmed cell death-ligand 1 expression.

The bromodomain-containing protein 4 (BRD4) is highly expressed in oral squamous cell carcinoma (OSCC) and plays a crucial role in tumour progression. However, the impact of BRD4 on the efficacy of chemotherapy and radiotherapy by regulating the expression of programmed cell death-ligand 1 (PD-L1) in OSCC remains unclear. In this study, we found that the BRD4 inhibitor JQ1 effectively enhanced the inhibitory effects of cisplatin and radiotherapy on cell proliferation and promoted the apoptosis of OSCC cells by cisplatin and radiotherapy. Furthermore, treatment with JQ1 reversed the increase of the expression of PD-L1 by cisplatin and radiotherapy, whereas the overexpression of PD-L1 partially countered the beneficial effects of JQ1 on the anticancer efficacy of cisplatin and radiotherapy. These results demonstrate that the inhibition of BRD4 improves the anticancer effect of chemotherapy and radiotherapy by suppressing the expression of PD-L1 in OSCC, suggesting that targeting BRD4 could be a promising therapeutic approach for chemo/radioresistant OSCC.

Antitumor effect of toosendanin on oral squamous cell carcinoma via suppression of p-STAT3

BackgroundToosendanin (TSN) exhibits potent antitumor activity against various tumor cell lines. However, its efficacy against oral squamous cell carcinoma (OSCC) remains unknown. Here, we investigated the effects of TSN on OSCC cells in vitro and verified them in vivo using a patient-derived xenograft (PDX) model.MethodsThe effect of TSN on OSCC cells was investigated by cytotoxicity assays and flow cytometry. The expression of proteins was detected by western blotting. An OSCC PDX model was constructed to further investigate the role of TSN in regulating the function of OSCC.ResultsThe cell viability of CAL27 and HN6 cells decreased as the concentration of TSN increased within the experimental range. Compared with controls, TSN at lower doses inhibited cell proliferation and induced apoptosis through S-phase cell cycle arrest. TSN inhibited OSCC cell proliferation by downregulating the STAT3 pathway through the inhibition of STAT3 phosphorylation. After successful construction of the OSCC PDX model with high pathological homology to the primary tumor and treatment with an intraperitoneal injection of TSN, we showed that TSN significantly reduced the tumor size of the PDX model mice without obvious toxicity.ConclusionsBoth in vitro and in vivo, TSN significantly inhibits the proliferation and promoted apoptosis of OSCC cells. Furthermore, TSN demonstrates potent inhibition of STAT3 phosphorylation, indicating its potential as a promising therapeutic agent for OSCC. Therefore, TSN holds great promise as a viable drug candidate for the treatment of OSCC.

Gastrodin overcomes chemoresistance via inhibiting Skp2-mediated glycolysis

Aerobic glycolysis, a typical phenotype in human tumors, is associated with tumor progression and chemotherapy resistance. The present study demonstrated that cisplatin-resistant oral squamous cell carcinoma (OSCC) cells exerted a stronger glycolysis ability, which was associated with hexokinase 2 (HK2) overexpression. Additionally, the tumor growth of OSCC cells was delayed in vivo and the glycolysis was notably decreased following HK2 knockdown. The natural compound screening revealed that gastrodin could be an effective candidate for OSCC therapy since it inhibited HK2-mediated glucose metabolism and promoted endogenous OSCC cell apoptosis. Furthermore, gastrodin could bind to protein kinase B (Akt) and suppress its activity, thus downregulating HK2 at the transcriptional level. Additionally, S-phase kinase-associated protein 2 (Skp2) was highly expressed in OSCC cells, while K63-linked ubiquitination of Akt was inhibited in Skp2-depleted cisplatin-resistant OSCC cells. Gastrodin could also inhibit the cisplatin resistance of OSCC cells in vivo, particularly when combined with the Skp2 inhibitor, SZL P1-41. Overall, the aforementioned finding suggested that targeting the Skp2-Akt axis could be a potential therapeutic strategy for treating OSCC and overcoming chemoresistance.

Simvastatin inhibits proliferation and promotes apoptosis of oral squamous cell carcinoma through KLF2 signal

ObjectivesThis study aimed to explore the role and specific mechanism of the cholesterol-lowering drug simvastatin in inhibiting oral squamous cell carcinoma (OSCC). MethodsThe proliferation, apoptosis, and migration levels of OSCC cells were detected by CCK8, quantitative real-time polymerase chain reaction, Western blot, colony formation, TdT-mediated dUTP Nick-End Labeling assay, and wound healing assay. The inhibitory effect of simvastatin in vivo was detected by a mouse xenograft tumor model. Immunohistochemistry and immunofluorescence staining were used to assess the KLF2 and β-catenin expressions in cells and tissues. ResultsKLF2 expression in OSCC cells and tissues was downregulated. The addition of KLF2 inducer, GGTI298, inhibited the proliferation and migration of OSCC cells. Simvastatin played a role in inhibiting the proliferation and promoting the apoptosis of OSCC cells. Moreover, it inhibited β-catenin expression and promoted KLF2 expression in OSCC cells. KLF2 siRNA reversed the effect of simvastatin on the proliferation and apoptosis of OSCC cells. ConclusionsKLF2, as a tumor suppressor gene, may be an important marker for diagnosing and treating OSCC. Simvastatin inhibits the progression of OSCC by regulating the KLF2 signal.

Cytotoxic, anti-proliferative, and apoptotic evaluation of Ramalina sinensis (Ascomycota, Lecanoromycetes), lichenized fungus on oral squamous cell carcinoma cell line; in-vitro study

BackgroundScientists and medical professionals are actively striving to improve the efficacy of treatment methods for oral squamous cell carcinoma (OSCC), the most frequently occurring cancer within the oral cavity, by exploring the potential of natural products. The active pharmacological compounds found in lichenized fungi have shown potential for aiding in cancer treatment. Recent research aims to evaluate the impact of the lichenized fungus Ramalina sinensis (R. sinensis) on the cell viability and apoptosis of OSCC cell lines, considering the anti-inflammatory and anti-cancer capabilities of lichens.MethodsRamalina sinensis (Ascomycota, Lecanoromycetes) was selected for investigation of its effects on a human oral squamous cell carcinoma cell line. Acetone and methanol extracts of R. sinensis on an OSCC cell line (KB cell line, NCBI Code: C152) were investigated. Viability was assessed by MTT assay analysis, and apoptotic cells were measured using flow cytometry analysis. Scratch assay was used to assess cell migration. The chemical composition and metabolic profiling of R. sinensis were investigated.ResultsThe growth and multiplication of KB cells were observed to undergo a gradual but remarkable inhibition when exposed to various concentrations. Specifically, concentrations of 6.25, 12.5, 25, 50, 100, and 200 μg/mL exhibited a significant suppressive effect on the proliferation of KB cells. The inhibition of cell proliferation exhibited a statistically significant difference between the extracts obtained from acetone and methanol. Flow cytometry results show an increase in apoptosis of OSCC cells by acetone extract. R. sinensis exerted a concentration-dependent inhibitory effect on the migration of OSCC cells. The chemical composition of R. sinensis was investigated using liquid chromatography positive ion electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS), and 33 compounds in the acetone and methanol extracts of R. sinensis were detected.ConclusionThe findings provide evidence supporting the beneficial effects of R. sinensis extract on inducing apoptosis in OSCC cells and exerting anti-cancer properties.

CircNFATC3 facilitated the progression of oral squamous cell carcinoma via the miR-520h/LDHA axis.

The aim of this study was to verify the effects of circular RNA nuclear factor of activated T-cells, cytoplasmic 3 (circNFATC3), in oral squamous cell carcinoma (OSCC) development. The levels of circNFATC3, microRNA-520h (miR-520h), and lactate dehydrogenase A (LDHA) were measured by qRT-PCR and western blot analysis. The cellular functions were assessed by using commercial kits, MTT assay, EdU assay, flow cytometry analysis, and transwell assay. The interactions between miR-520h and circNFATC3 or LDHA were confirmed by dual-luciferase reporter assay. Finally, the mice test was enforced to evaluate the character of circNFATC3. We observed that the contents of circNFATC3 and LDHA were upregulated and miR-520h levels were downregulated in OSCC tissues compared with those in paracancerous tissues. For functional analysis, circNFATC3 knockdown repressed the cell glycolysis metabolism, cell proliferation, migration, and invasion, although it improved cell apoptosis in OSCC cells. LDHA could regulate the development of OSCC. circNFATC3 acted as a miR-520h sponge to modulate LDHA expression. In addition, the absence of circNFATC3 subdued tumor growth in vivo. In conclusion, circNFATC3 promoted the advancement of OSCC by adjusting the miR-520h/LDHA axis.

Hispolon induces apoptosis in oral squamous cell carcinoma cells through JNK/HO-1 pathway activation.

Oral squamous cell carcinoma (OSCC) has a high recurrence rate and poor prognosis. Hispolon, a polyphenolic compound with antiviral, antioxidant, and anticancer activities, is a potential chemotherapy agent. However, few studies have investigated the anti-cancer mechanism of hispolon in oral cancer. This present study used the cell viability assay, clonogenic assay, fluorescent nuclear staining, and flow cytometry assay to analyse the apoptosis-inducing effects of hispolon in OSCC cells. After hispolon treatment, the apoptotic initiators, cleaved caspase-3, -8, and - 9, were upregulated, whereas the cellular inhibitor of apoptosis protein-1 (cIAP1) was downregulated. Furthermore, a proteome profile analysis using a human apoptosis array revealed the overexpression of heme oxygenase-1 (HO-1) by hispolon, which was determined to be involved in caspase-dependent apoptosis. Moreover, cotreatment with hispolon and mitogen-activated protein kinase (MAPK) inhibitors revealed that hispolon induces apoptosis in OSCC cells through activation of the c-Jun N-terminal kinase (JNK) pathway and not the extracellular signal-regulated kinase (ERK) or p38 pathway. These findings indicate that hispolon may exert an anticancer effect on oral cancer cells by upregulating HO-1 and inducing caspase-dependent apoptosis by activating the JNK pathway.

Network-Based Method to Investigate the Promoted Cell Apoptosis Mechanisms of Oridonin in OSCC through the RNA-Transcriptome.

The morbidity of oral cancer is high in the world. Oridonin is a traditional Chinese medicine that can effectively inhibit oral squamous cell carcinoma (OSCC) growth, but its mechanism remains unclear. Our previous data showed that oridonin inhibited CAL-27 cell proliferation and promoted apoptosis. Herein, we explored the mechanism and target of oridonin in human OSCC through RNA sequencing and integration of multiple bioinformatics analysis strategies. Differences in gene expression can be analyzed with RNA sequencing. Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), gene set enrichment analysis (GSEA), Disease Ontology (DO), and other enrichment analyses were used to evaluate differentially expressed genes (DEGs). Protein-protein interaction (PPI) networks were built via the STRING database. It was found that tumor necrosis factor (TNF) signaling pathway, cytokine-cytokine receptor interaction, and nuclear factor-kappa B (NF-kappaB) signaling pathway were associated with the therapeutic effects of oridonin in OSCC. Three key genes (BIRC3, TNFSF10, and BCL6) were found to associate with cell apoptosis in OSCC cells treated with oridonin. Quantitative PCR assays verified the expression of apoptosis-related DEGs: TNFSF10, BIRC3, AIFM2, BCL6, BCL2L2, and Bax. Western blots were employed for verifying proteins expression associated with DEGs: cleaved caspase 3, Bax, Bcl-w, anti-cIAP2, and anti-TRAIL. In conclusion, our findings reveal the molecular pathways and targets by which oridonin can treat and induce cytotoxic effects in OSCC: by affecting the signaling including TNF, NF-κB, and cytokine-cytokine receptor interaction and by regulating the key gene BIRC3, TNFSF10, and BCL6. It should be noted that further clinical trial validation is very necessary. Combined with current research trends, our existing research may provide innovative research drugs for the treatment of OSCC.

Exosome-mediated long noncoding RNA (lncRNA) PART1 suppresses malignant progression of oral squamous cell carcinoma via miR-17-5p/SOCS6 axis.

Exosomes derived from oral squamous cell carcinoma (OSCC) could modulate OSCC development. This study aimed to explore effects of exosome-mediated lncRNA PART1 on OSCC cells. This study was performed in Tianjin Medical University Cancer Institute from February 2021 to March 2022. Bioinformatic analysis was performed on the public database GEPIA (http://gepia.cancer-pku.cn/). Exosomes isolated from cell lines squamous cell carcinoma 9 (SCC9) and Centre Antoine Lacassagne-27 (CAL27) were identified by transmission electron microscope and western blot. Exosome-mediated lncRNA PART1, microRNA-17-5p(miR-17-5p) and suppressor of cytokine signaling 6(SOCS6) RNA expressions were assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Cell counting kit8(CCK-8), caspase-3 activity, and flow cytometry were applied to evaluate OSCC cell viabilities and apoptosis. Meanwhile, OSCC cell migratory ability and invasiveness were evaluated using transwell assay. Bindings between miR-17-5p and lncRNA PART1 or SOCS6 were validated using the luciferase reporter test. Western blot was used for detecting the protein levels of SOCS6, phosphorylated signal transducer and activator of transcription 3 (STAT3) and STAT3. : According to GEPIA, lncRNA PART1 was downregulated in OSCC tissue samples and cells, and it had a positive correlation with the good prognosis of Head and neck squamous cell cancer (HNSCC) patients. After the exosomes from OSCC cells were isolated and verified, PART1 was then confirmed to be secreted by exosomes. Further, overexpression of exosome-mediated lncRNA PART1 inhibited OSCC cell viabilities, migration, and invasiveness but facilitated OSCC cell apoptosis. PART1 upregulated SOCS6 through sponging miR-17-5p. Moreover, exosome-mediated lncRNA PART1 suppressed the phosphorylation of STAT3. Exosome-mediated lncRNA PART1 could mediate the OSCC progression via miR-17-5p/SOCS6 axis in vitro, suggesting that lncRNA PART1 might be a target for treating OSCC.

Curcumol Exerts Antitumor Effect via Inhibiting EGFR-Akt-Mcl-1 Signaling.

Dysfunction of epidermal growth factor receptor (EGFR) signaling plays a critical role in the tumorigenesis of oral squamous cell carcinoma (OSCC). In the present study, the data analysis results of immunohistochemistry and the TCGA database verified that the expression of EGFR is significantly upregulated in OSCC tumor tissues, and depletion of EGFR inhibits the growth of OSCC cells in vitro and in vivo. Moreover, these results showed that the natural compound, curcumol, exhibited a profound antitumor effect on OSCC cells. Western blotting, MTS, and immunofluorescent staining assays indicated that curcumol inhibited cell proliferation and induced intrinsic apoptosis in OSCC cells via downregulating myeloid cell leukemia 1 (Mcl-1). A mechanistic study revealed that curcumol inhibited the EGFR-Akt signal pathway, which activated GSK-3[Formula: see text]-mediated Mcl-1 phosphorylation. Further research showed that curcumol-induced Mcl-1 Ser159 phosphorylation is required to disrupt the interaction between deubiquitinase JOSD1 and Mcl-1 and eventually induce Mcl-1 ubiquitination and degradation. In addition, curcumol administration can effectively inhibit CAL27 and SCC25 xenograft tumor growth and is well-tolerated in vivo. Finally, we demonstrated that Mcl-1 is upregulated and positively correlates with p-EGFR and p-Akt in OSCC tumor tissues. Collectively, the present results provide new insights into the antitumor mechanism of curcumol, identifying it as an attractive therapeutic agent that reduces Mcl-1 expression and inhibits OSCC growth. Targeting EGFR/Akt/Mcl-1 signaling could be a promising option in the clinical treatment of OSCC.

Tanshinone IIA inhibits cell viability and promotes PUMA-mediated apoptosis of oral squamous cell carcinoma.

Apoptosis alteration is responsible for tumorigenesis and tumor resistance to therapies. The natural product Tanshinone IIA (Tan IIA) exhibits potent inhibitory effects against various tumors. However, the effect of Tan IIA on apoptosis and its underlying mechanism remains elusive in oral squamous cell carcinoma (OSCC). Here, we demonstrated that Tan IIA dose-dependently suppressed cell viability and colony formation in CAL27, SCC4, and SCC25 cells. Moreover, Tan IIA inhibited Akt activation from inducing Foxo3a dephosphorylation and PUMA-mediated apoptosis. PUMA or Foxo3a knockdown compromised the inhibitory effect of Tan IIA on OSCC cells. Tan IIA administration inhibited CAL27-deprived xenograft tumor growth and increased PUMA expression in vivo. Tan IIA synergistically intensified the efficacy of CDDP/5-FU-based chemotherapy on OSCC cells. Overall, our results revealed that Tan IIA exerted potent antitumor effects via promoting PUMA-mediated apoptosis in OSCC cells.

Targeted Knockdown of Macrophage Migration Inhibitory Factor Enhances UVB Irradiation-Induced Apoptosis Via Increasing ROS Generation in Oral Squamous Cell Carcinoma.

Objectives: We investigated the effects of macrophage migration inhibitory factor (MIF) knockdown or overexpression combined with ultraviolet radiation B (UVB) irradiation on cell proliferation and apoptosis of oral squamous cell carcinoma (OSCC). Methods: MIF expression in OSCC and adjacent tissues was detected by immunohistochemistry. MIF expression in human immortalized oral epithelial cells (HIOEC) and OSCC cells was detected by western blotting. MIF was knocked down or overexpressed in OSCC cell lines (SCC-25 and CAL-27). OSCC cells were set up into control (CON), MIF overexpression/knockdown (oeMIF/shMIF), CON + UVB, and oeMIF + UVB/shMIF + UVB groups based on their exposure to UVB irradiation. Cell line proliferation was studied using a cell counting kit-8 (CCK-8) and colony formation assays. Flow cytometry was applied for determination of apoptosis, cell cycle, reactive oxygen species (ROS) abundance, and mitochondrial membrane potential. Apoptosis-related proteins were assayed by western blotting. Results: The expression of MIF was significantly higher in OSCC tissues and cell lines than in adjacent tissues and HIOEC. MIF knockdown accompanied by UVB irradiation significantly hampered cell viability and proliferation compared to MIF knockdown or UVB irradiation alone. Western blotting and flow cytometry showed that MIF knockdown combined with UVB irradiation not only induced apoptosis via the mitochondrial pathway but also mediated the cell cycle. Flow cytometry showed that ROS and mitochondrial membrane potential depolarization were increased in the combination treatment groups compared with the mono-treatment groups. Additionally, the ROS scavenger N-acetylcysteine significantly attenuated MIF knockdown combined with UVB irradiation-induced apoptosis and reversed MIF knockdown combined with UVB irradiation-induced MAPK activation. Conclusion: MIF knockdown combined with UVB irradiation significantly inhibited the proliferation of OSCC cells. MIF was involved in UVB-induced ROS generation and enhanced UVB irradiation-induced mitochondria-dependent apoptosis of OSCC cells by activating the MAPK pathway. This suggests that MIF-targeted therapy combined with UVB irradiation may be a novel approach for treating OSCC.

Long noncoding RNA MEG3 inhibits oral squamous cell carcinoma progression via GATA3.

Oral squamous cell carcinoma (OSCC) accounts for about 90% of oral cancers. Expression of the long noncoding RNA (lncRNA) maternally expressed 3 (MEG3) has previously been reported to be downregulated in OSCC, and its overexpression can inhibit proliferation, migration, and invasion and promote apoptosis of OSCC cells. However, the mechanism underlying MEG3 downregulation in OSCC has not been well characterized. Here we report that low expression of MEG3 is caused by H3K27me3 modification of the MEG3 gene locus, and this is associated with the poor prognosis of OSCC. Overexpression of MEG3 inhibited the proliferation and invasion of OSCC cells. We observed that MEG3 was modified by m6A and bound to YTHDC1. Enhancer-controlled genes positively regulated by MEG3 were functionally enriched for the 'negative regulation of Wnt signaling pathway' term, as determined using metascape. GATA3 was predicted to be a transcription factor for these genes, and was demonstrated to bind to MEG3. Knockdown of GATA3 countered the effects on proliferation, invasion, and increased transcription of HIC1 and PRICKLE1 induced by MEG3 overexpression. In conclusion, our data suggest that MEG3 is downregulated in OSCC due to trimethylation of H3K27 at the MEG3 gene locus. The inhibitory effect of MEG3 on proliferation and invasion of OSCC cells was dependent on the binding of GATA3.

Depletion of PARP10 inhibits the growth and metastatic potential of oral squamous cell carcinoma.

Background: Although poly (ADP-ribose) polymerase family member 10 (PARP10) has been implicated in the progression of multiple cancer types, its role in oral squamous cell carcinoma (OSCC) remains unknown. This study aimed to examine the function of PARP10 in OSCC and investigate the underlying mechanisms. Methods: The expression of PARP10 in OSCC was investigated in OSCC patient cohorts. Kaplan-Meier curve analysis was performed to assess the association between PARP10 and prognosis in OSCC. Correlation between PARP10 expression and the related variables was analyzed by χ2 test. CKK-8, transwell assay, western blot, immunohistochemistry, immunofluorescence, and bioinformatic analysis, were applied to clarify the role of PARP10 in OSCC. Results: PARP10 was found to be markedly elevated in OSCC tissues. The upregulation of PARP10 predicted shorter overall survival and disease-specific survival and was significantly correlated with several malignant features. Moreover, depletion of PARP10 markedly inhibited the proliferation, migration, and invasion of OSCC cells, and promoted OSCC cell apoptosis, and resulted in alterations of relevant proteins. Furthermore, a positive correlation was observed between the expression of PARP10 and Ki67, PARP1, MMP2, and VEGF. In addition, depletion of PARP10 impaired the PI3K-AKT and MAPK signaling pathways. Conclusion: PARP10 is involved in the progression of OSCC via regulation of PI3K-AKT and MAPK signaling pathways.

Deoxypodophyllotoxin Induces ROS-Mediated Apoptosis by Modulating the PI3K/AKT and p38 MAPK-Dependent Signaling in Oral Squamous Cell Carcinoma.

Deoxypodophyllotoxin (DPT), a naturally occurring flavonolignan, possesses several pharmacological properties, including anticancer property. However, the mechanisms underlying DPT mode of action in oral squamous cell carcinoma (OSCC) remain unknown. This study aimed to investigate the anticancer effects of DPT on OSCC and the underlying mechanisms. Results of the MTT assay revealed that DPT significantly reduced the cell viability in a time- and dose-dependent manner. Flow cytometry analysis revealed that DPT induces apoptosis in OSCC cells in a dose-dependent manner. Moreover, DPT enhanced the production of mitochondrial reactive oxygen species (ROS) in OSCC cells. Mechanistically, DPT induced apoptosis in OSCC cells by suppressing the PI3K/AKT signaling pathway while activating the p38 MAPK signaling to regulate the expression of apoptotic proteins. Treatment with SC79, an AKT activator, reversed the effects of DPT on AKT signaling in OSCC cells. Taken together, these results provide the basis for the use of DPT in combination with conventional chemotherapy for the treatment of oral cancer.

LncRNA TUG1 promotes the development of oral squamous cell carcinoma by regulating the MAPK signaling pathway by sponging miR-593-3p

ABSTRACT Dysregulation of non‐coding RNAs (ncRNAs) has been proved to play important roles in oral squamous cell carcinoma (OSCC). This study aimed to determine the combined role of lncRNA TUG1, miR-593-3p, and MAPK signaling in oral squamous cell carcinoma (OSCC) development. Here, we found that TUG1 was up-regulated in OSCC tissues and cell lines. Silencing TUG1 suppressed proliferation migration, invasion and promoted apoptosis of OSCC cells. We also validated that knockdown of TUG1 suppressed MAPK signaling pathway and inhibited EMT process in OSCC cells. Then, a novel LncRNA TUG1/ miR-593-3p/MAPK axis was verified to rescue cell viability in OSCC cells. Mechanistically, miR-593-3p bound to lncRNA TUG1, and lncRNA TUG1 positively regulated MAPK related proteins through acting as RNA sponger for miR-593-3p. Further gain- and loss-of-function experiments evidenced that the protective effects of lncRNA TUG1 knock-down on OSCC cells were abrogated by silencing miRNA-593-3p. The OSCC nude mice model experiments demonstrated that depletion of TUG1 further inhibited tumor growth. In conclusion, appropriate diagnostic biomarkers and therapies for OSCC can be identified by targeting the TUG1/miR-593-3p/MAPK axis.