Silencing LCN2 suppresses oral squamous cell carcinoma progression by reducing EGFR signal activation and recycling.

BACKGROUND: EGFR is an important signal involved in tumor growth that can induce tumor metastasis and drug resistance. Exploring targets for effective EGFR regulation is an important topic in current research and drug development. Inhibiting EGFR can effectively inhibit the progression and lymph node metastasis of oral squamous cell carcinoma (OSCC) because OSCC is a type of cancer with high EGFR expression. However, the problem of EGFR drug resistance is particularly prominent, and identifying a new target for EGFR regulation could reveal an effective strategy. METHODS: We sequenced wild type or EGFR-resistant OSCC cells and samples from OSCC patients with or without lymph node metastasis to find new targets for EGFR regulation to effectively replace the strategy of directly inhibiting EGFR and exert an antitumor effect. We then investigated the effect of LCN2 on OSCC biological abilities in vitro and in vivo through protein expression regulation. Subsequently, we elucidated the regulatory mechanism of LCN2 through mass spectrometry, protein interaction, immunoblotting, and immunofluorescence analyses. As a proof of concept, a reduction-responsive nanoparticle (NP) platform was engineered for effective LCN2 siRNA (siLCN2) delivery, and a tongue orthotopic xenograft model as well as an EGFR-positive patient-derived xenograft (PDX) model were applied to investigate the curative effect of siLCN2. RESULTS: We identified lipocalin-2 (LCN2), which is upregulated in OSCC metastasis and EGFR resistance. Inhibition of LCN2 expression can effectively inhibit the proliferation and metastasis of OSCC in vitro and in vivo by inhibiting EGFR phosphorylation and downstream signal activation. Mechanistically, LCN2 binds EGFR and enhances the recycling of EGFR, thereby activating the EGFR-MEK-ERK cascade. Inhibition of LCN2 effectively inhibited the activation of EGFR. We translated this finding by systemic delivery of siLCN2 by NPs, which effectively downregulated LCN2 in the tumor tissues, thereby leading to a significant inhibition of the growth and metastasis of xenografts. CONCLUSIONS: This research indicated that targeting LCN2 could be a promising strategy for the treatment of OSCC.

GSDMD enhances cisplatin-induced apoptosis by promoting the phosphorylation of eIF2α and activating the ER-stress response.

GSDMD is the key effector of pyroptosis, but its non-pyroptosis-related functions have seldom been reported. Here, we report that GSDMD is overexpressed in different types of tumours, including head and neck squamous-cell carcinoma, and it promotes the sensitivity of tumour cells to cisplatin. Unexpectedly, the enhanced cisplatin sensitivity is mediated by apoptosis but not pyroptosis, the well-known function of GSDMD. Furthermore, we found that GSDMD can activate the unfolded protein response by promoting the phosphorylation of eIF2α. Mechanistically, we demonstrated that GSDMD can directly bind to eIF2α and enhance the interaction between eIF2α and its upstream kinase PERK, leading to eIF2α phosphorylation. Consequently, the protein levels of ATF-4 were upregulated, downstream apoptosis-related proteins such as CHOP were activated, and apoptosis was induced. Remarkably, activation of endoplasmic-reticulum (ER) stress induced by GSDMD promotes cell apoptosis during cisplatin chemotherapy, thereby increasing the treatment sensitivity of tumours. Therefore, for the first time, our work reveals an unreported nonpyroptotic function of the classic pyroptosis protein GSDMD: it promotes cell apoptosis during cisplatin chemotherapy by inducing eIF2α phosphorylation and ER stress, which are related to the drug sensitivity of tumours. Our study also indicated that GSDMD might serve as a biomarker for cisplatin sensitivity.

A Novel Prognostic Model for Oral Squamous Cell Carcinoma: The Functions and Prognostic Values of RNA-Binding Proteins.

PURPOSE: The biological roles and clinical significance of RNA-binding proteins (RBPs) in oral squamous cell carcinoma (OSCC) are not fully understood. We investigated the prognostic value of RBPs in OSCC using several bioinformatic strategies. MATERIALS AND METHODS: OSCC data were obtained from a public online database, the Limma R package was used to identify differentially expressed RBPs, and functional enrichment analysis was performed to elucidate the biological functions of the above RBPs in OSCC. We performed protein-protein interaction (PPI) network and Cox regression analyses to extract prognosis-related hub RBPs. Next, we established and validated a prognostic model based on the hub RBPs using Cox regression and risk score analyses. RESULTS: We found that the differentially expressed RBPs were closely related to the defense response to viruses and multiple RNA processes. We identified 10 prognosis-related hub RBPs (ZC3H12D, OAS2, INTS10, ACO1, PCBP4, RNASE3, PTGES3L-AARSD1, RNASE13, DDX4, and PCF11) and effectively predicted the overall survival of OSCC patients. The area under the receiver operating characteristic (ROC) curve (AUC) of the risk score model was 0.781, suggesting that our model exhibited excellent prognostic performance. Finally, we built a nomogram integrating the 10 RBPs. The internal validation cohort results showed a reliable predictive capability of the nomogram for OSCC. CONCLUSION: We established a novel 10-RBP-based model for OSCC that could enable precise individual treatment and follow-up management strategies in the future.

Long non-coding RNA maternally expressed gene 3 inhibits osteogenic differentiation of human dental pulp stem cells via microRNA-543/smad ubiquitin regulatory factor 1/runt-related transcription factor 2 axis.

OBJECTIVE: The aim of the present study was to investigate the biological roles and underlying mechanism of the long non-coding RNA maternally expressed gene 3 (MEG3) on osteogenic differentiation of human dental pulp stem cells (hDPSCs). METHODS: The expression levels of MEG3, microRNA-543 (miR-543), osterix, osteopontin, osteocalcin and runt-related transcription factor 2 (RUNX2) were measured by quantitative real-time PCR (qRT-PCR). Alkaline phosphatase (ALP) activity assay and alizarin red S staining (ARS) were used to measure the impacts exerted by MEG3, miR-543 on osteogenic differentiation. Cell proliferation was measured by MTT assay. In addition, the targeted relationships between miR-543, MEG3, and Smad ubiquitin regulatory factor 1 (SMURF1) were assessed through dual luciferase reporter assay. RESULTS: During osteogenic induction, the expression of MEG3 was gradually reduced, whereas the expression of miR-543, osterix, osteopontin, osteocalcin and RUNX2 were gradually increased. Functional analysis implied that MEG3 overexpression or miR-543 inhibition reduced the cell proliferation, ALP activity, ARS levels, and decreased the expression of osteoblast-related proteins. Moreover, MEG3 promoted SMURF1 expression by directly targeting miR-543 as a competing endogenous RNA. Furthermore, overexpression of miR-543 or silencing SMURF1 could reverse the inhibitory effects of MEG3 on the osteogenic differentiation of hDPSCs. CONCLUSIONS: In conclusion, our study revealed that overexpression of MEG3 inhibited hDPSCs osteogenic differentiation via miR-543/SMURF1/RUNX2 regulatory network, which may contribute to the functional regulation and clinical applications of hDPSCs.

Upregulation of long non-coding RNA FOXD2-AS1 promotes progression and predicts poor prognosis in tongue squamous cell carcinoma.

BACKGROUND: Accumulating evidences suggest that lncRNA FOXD2-AS1 plays an important role in tumor progression, however, its function in tongue squamous cell carcinoma (TSCC) remains unknown. This research aims to investigate the function and mechanism of FOXD2-AS1 in the modulation of tongue squamous cell carcinoma progression. METHODS: Expression of FOXD2-AS1 was detected in TSCC tissues and TCGA data. Receiver operating characteristic curves (ROCs) analysis and bioinformatic analysis of TCGA data were performed to investigate the role of FOXD2-AS1 in TSCC prognosis. After siRNA-mediated downregulation of FOXD2-AS1, wound healing assay, Transwell migration and invasion assays, and MTS proliferation assay were conducted to explore the effects that FOXD2-AS1 exerted on SCC-9 and CAL-27 cell lines. Western blotting was performed to detect the downstream protein changes. RESULTS: Compared to the normal tissues and samples, FOXD2-AS1 significantly highly expressed in TSCC tissues and in TSCC samples of TCGA data, and high expression of FOXD2-AS1 was associated with lymphatic metastasis and poor TNM stages. ROC analysis and bioinformatic analysis of TCGA data further suggested that high expression of FOXD2-AS1 was associated with TSCC poor prognosis. Downregulation of FOXD2-AS1 inhibited the migration and invasion of SCC-9 and CAL-27 cell lines. Western blotting showed that the expression of p-p44 and p-p65 downregulated after FOXD2-AS1 knockdown. CONCLUSION: High expression of FOXD2-AS1 promotes TSCC progression through modulating NF-kB and ERK MAPK signaling pathways and is associated with TSCC poor prognosis, it could be a novel therapeutic target and prognostic biomarker for TSCC.

Autophagy inhibits TLR4-mediated invasiveness of oral cancer cells via the NF-κB pathway.

OBJECTIVES: Toll-like receptor 4 (TLR4) is abnormally expressed in oral cancer tissues and promotes cancer cell invasion. The purpose of this study was to clarify the mechanism by which autophagy regulates oral cancer invasion through the TLR4-NF-κB pathway. SUBJECTS AND METHODS: We examined TLR4 expression in oral cancer tissues and analysed the relationship between its expression and clinicopathological features. The invasion and migration of LPS-stimulated oral cancer cells with up- or downregulation of TLR4 expression was detected in addition to NF-κB signalling and autophagy levels. Furthermore, the role of autophagy in regulating TLR4-mediated cell invasiveness was explored by silencing the expression of key autophagy genes ATG7 and p62. RESULTS: We found that TLR4 overexpression was closely related to cervical lymphatic metastasis and poor survival. TLR4 activated the NF-κB pathway to promote the invasiveness of OSCC cells, and autophagy partly inhibited invasiveness by suppressing the NF-κB pathway. We observed that p62 translocated from the cytoplasm to the nucleus when autophagy was activated by LPS. Finally, silencing p62 further promoted LPS-mediated cell invasiveness. CONCLUSION: Toll-like receptor 4 significantly enhanced the invasiveness of OSCC cells. Autophagy may regulate cell invasiveness through the NF-κB pathway by modulating both the cytoplasmic and nuclear levels of p62.

Tumor necrosis factor receptor-associated factor 6 mediated the promotion of salivary adenoid cystic carcinoma progression through Smad-p38-JNK signaling pathway induced by TGF-ß.

BACKGROUND: Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) has been proved to play an important role in tumorigenesis, invasion, and metastasis. However, its precise role salivary adenoid cystic carcinoma (SACC) has not been determined. The aim of this study was to explore the role of TRAF6 in SACC including invasion and metastasis of SACC cells. MATERIALS AND METHODS: Immunohistochemistry and quantitative real-time PCR were performed in SACC tissues paired with their adjacent normal tissues to analyze the expression of TRAF6. Downstream proteins expression was explored when TRAF6 was knockdown by siRNA. RESULTS: The results show that TRAF6 is upregulated in SACC samples, especially in SACC with metastasis, which is closely correlated with an aggressive phenotype (P = .0073) and shorter life survival span (P = .0061) in SACC patients. Knockdown of TRAF6 can attenuate the promotion effect of SACC cell invasion induced by TGF-ß. Western blot results also showed that silencing TRAF6 expression can inhibit the activation of SMAD2, SMAD3, ERK, p38, and JNK induced by TGF-ß in SACC cells. CONCLUSION: These data suggested that TRAF6 regulates TGF-ß-mediated SACC progression through SMAD2/3-ERK-p38-JNK cascades.

Down-regulation of miR-125a-5p is associated with salivary adenoid cystic carcinoma progression via targeting p38/JNK/ERK signal pathway.

Salivary adenoid cystic carcinoma (SACC) is a relatively uncommon epithelial-like malignancy that can occur in the head and neck region. Despite its slow growth, this aggressive salivary gland tumor frequently recurs and metastasizes to distant organs since lacking effective chemotherapy treatment. MicroRNAs are key regulators in tumor metastasis and progression, but their roles during SACC progression have not been illustrated. In current study, we demonstrate that miR-125a-5p is down-regulated in SACC and closely related to the metastasis and progression in human SACC specimens. In vitro, miR-125a-5p mimic can suppress SACC cell migration and invasion; while blocking miR-125a-5p can relieve the inhibition effect. By using dual-luciferase assay, we confirmed that miR-125a-5p directly targeted to p38 and tissue samples of patients indicated the negative correlation between miR-125a-5p and p38; clinical analysis also showed that low level expression of miR-125a-5p is closely associated with poor prognosis of SACC. Furthermore, down-regulation of miR-125a-5p triggered downstream p38/JNK/ERK activation. Taken together, our results indicate that down-regulation of miR-125a-5p promotes SACC progression through p38 signal pathway and miR-125a-5p can be a potential therapeutic target of SACC.

FGF1-FGFR1 axis promotes tongue squamous cell carcinoma (TSCC) metastasis through epithelial-mesenchymal transition (EMT).

Increasing evidences suggest a close association between tumor metastasis and the inflammatory factors secreted by tumor microenvironment. It has been reported that epithelial mesenchymal-transition (EMT) plays a significant role during multiple types of tumor metastasis and progression induced by inflammatory factor from tumor microenvironment. Previous researches implied that fibroblast growth factor 1 (FGF1) can promote tumor progression and cause poor prognosis in several types of malignant tumors via interacting with its receptor fibroblast growth factor receptor 1 (FGFR1). However, the effects of FGF1-FGFR1 on tongue squamous cell carcinoma (TSCC) are not yet completely understood. In the present study, we evaluated the effects and function of FGF1-FGFR1 axis on TSCC metastasis. In addition, we investigated whether the EMT pathway is involved in these effects, thus modulating the TSCC progression. The expression of FGFR1 was measured both in tongue cancer cell lines and tissues by qRT-PCR and western blot. We found that FGFR1 was up-regulated in TSCC tissues compared to non-neoplastic tongue tissues. Additionally, overexpression of FGFR1 is positively associated with poor differentiation and metastasis potential. Furthermore, the function of FGF1-FGFR1 was examined in TSCC cell line. The results implied that FGF1 can obviously promote Cal27 cells migration and invasion abilities through FGFR1, while the motile and invasive capabilities can be severely attenuated when knockdown the expression of FGFR1 by specific siRNAs. Further investigation results show that FGF1-FGFR1 axis promotes TSCC metastasis by modulating EMT pathway. However, this effect can be inhibited by blocking the FGF1-FGFR1 axis using FGFR1 specific siRNAs. In conclusion, our findings of the present study provide the evidences that FGF1-FGFR1 axis promotes the TSCC metastasis through the EMT pathway.

RECK overexpression reduces invasive ability in ameloblastoma cells.

BACKGROUND: Ameloblastoma is a frequent odontogenic neoplasm characterized by local invasiveness and high risk of recurrence. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a tumor suppressor that inhibits metastasis and angiogenesis. The aim of this study was to investigate effects of RECK overexpression on invasive potential in ameloblastoma cells. METHODS: Lentiviral vectors containing human RECK gene were created and subsequently stably transfected into immortalized ameloblastoma cell line hTERT(+) -AM. Functional characteristics of hTERT(+) -AM cells with stable RECK overexpression included proliferation, migration, invasion, and regulation of matrix metalloproteinases (MMP)-2, MMP-9 measured by zymography or commercially available assays. RESULTS: The stable and higher expression of RECK mRNA and protein (P < 0.01) was detected in RECK-transfected hTERT(+) -AM cells. RECK overexpression caused a decrease in migration and invasion (P < 0.01) for hTERT(+) -AM cells and a decrease in activity of MMP-2, MMP-9 (P < 0.01). Proliferation was not affected by RECK overexpression (P > 0.05). CONCLUSIONS: Overexpression of RECK gene significantly inhibited cell invasive ability of hTERT(+) -AM cells, suggesting RECK may be a new target for ameloblastoma treatment.

[Reconstruction of tongue defects following oral cancer ablation with extended supraclavicular fasciocutaneous island flap].

OBJECTIVE: To assess the reliability and usefulness of the extended supraclavicular fasciocutaneous island flap (eSIF) for reconstructing soft tissue defects followinng tongue cancer ablation. METHODS: Twenty-two tongue defects in 22 patients with tongue cancer were repaired with eSIF after resection of the tongue malignant tumours. The sizes of the skin paddle ranged from (4 cm × 6 cm) to (8 cm × 14 cm) (average: 5.5 cm × 8.7 cm). RESULTS: The eSIF survived in twenty cases, including two cases with minimal partial necrosis. The patients were follwed up for 5 - 16 months. Eighteen patients were alive with disease free, two were alive with disease and two died of a lung and liver metastasis. CONCLUSIONS: The eSIF is reliable for reconstructing oral defects following the ablation of advanced oral malignant tumors.

Anesthetic efficacy of inferior alveolar nerve block plus buccal infiltration or periodontal ligament injections with articaine in patients with irreversible pulpitis in the mandibular first molar.

OBJECTIVE: We compared the anesthetic efficacy of inferior alveolar nerve block (IANB) plus buccal infiltration (BI) and IANB plus periodontal ligament (PDL) articaine injections in patients with irreversible pulpitis in the mandibular first molar. STUDY DESIGN: Fifty-seven volunteers, patients with irreversible pulpitis in the mandibular first molar admitted to the Department of Stomatology, Second Affiliated Hospital, Sun Yat-Sen University, randomly received conventional IANB, containing 1.7 mL 4% articaine/HCl with 1:100,000 epinephrine, plus either BI or PDL injections containing 0.4 mL articaine/HCl with 1:100,000 epinephrine. The patients recorded the pain of the injections and endodontic access on a Heft-Parker visual analog scale (VAS). RESULTS: According to the VAS scores, all patients experienced no or mild pain with BI and PDL injections after the application of IANB. Anesthetic success occurred in 81.48% for IANB plus BI (IANB/BI) compared with 83.33% for IANB plus PDL injection (IANB/PDL injection). None of the observed differences between the 2 groups was significant (P > .05). CONCLUSION: Both injection combinations resulted in high anesthetic success in patients with irreversible pulpitis in the mandibular first molar.