Bioinformatic analysis and verification of a lipid metabolism-related long noncoding RNA prognostic signature for head and neck squamous cell carcinoma.

PURPOSE: Both lipid metabolism reprogramming and lncRNAs exert effects on tumor development. We aimed to predict the prognosis of head and neck squamous cell carcinoma (HNSCC) based on lipid metabolism-related (LR)-lncRNAs. METHODS: LR-lncRNAs were determined from the RNA-ref profiles of HNSCC samples in The Cancer Genome Atlas (TCGA). The prognostic model was established by univariate Cox and Lasso regression analysis. Clinical relevance and predictive accuracy were investigated, and external validation was also performed in the Gene Expression Omnibus (GEO) cohort. Tumor immune infiltration and relevant functional analysis, including the association of autophagy with prognostic signatures, were conducted through single-sample gene set enrichment analysis (ssGSEA). The regulatory network of candidate LR-lncRNAs was investigated via coexpression, ceRNA and cis/trans acting interactions. Potential genes were selected through qRT-PCR analysis, and their effects on tumor biological activities and autophagic activity were explored after gene knockdown. RESULTS: A total of 222 LR-lncRNAs were identified. Among the 41 genes with prognostic significance, 17 lncRNAs were eligible for the risk model. Patients in the high-risk group had a poorer prognosis than those in the low-risk group, and the risk score was found to be positively associated with tumor microenvironment infiltration via multiple algorithms. Furthermore, improved prognosis was found in patients with high autophagic scores and low risk scores, and autophagy-related genes such as PINK1 and CCL2 showed significantly lower expression in the low-risk group. The expression of immune checkpoint genes such as CD28, CTLA4 and PDCD1 decreased dramatically in the high-risk group. The target genes of candidate lncRNAs were confirmed, such as ENO2 and PPAR-gamma. Furthermore, MIR4435-2HG was the most significantly overexpressed lncRNA in HNSCC cell lines and tumor samples, which could promote proliferation and migration and inhibit apoptosis. Additionally, MIR4435-2HG silencing activated autophagy by increasing LC3B expression. CONCLUSION: This study constructed an LR-lncRNA prognostic signature for HNSCC and indicated its relationships with tumor immunity and autophagy, which provides a promising future for LR-lncRNA-oriented prognostic tools and therapeutic targets.

Graphdiyne Oxide-Mediated Photodynamic Therapy Boosts Enhancive T-Cell Immune Responses by Increasing Cellular Stiffness.

Purpose: Nanomaterial-based photodynamic therapy (PDT) has been commonly used for the treatment of cancerous tumors. Despite significant achievements made in this field, the intrinsic impact of nanomaterials-based PDT on the mechanical properties of oral squamous cell carcinoma (OSCC) cells is not entirely understood. Here, we used atomic force microscopy (AFM) to measure the stiffness of OSCC cells subjected to PDT in co-culture systems to evaluate the T cell-mediated cancer cell-killing effects. Methods: In this study, AFM was used to assess the stiffness of PDT-subjected cells. The phototoxicity of graphdiyne oxide (GDYO) was assessed using confocal laser scanning microscopy (CLSM), measurements of membrane cholesterol levels, and assessments of the F-actin cytoskeleton. A co-culture system was used to evaluate the effects of CD8+ T cells (cytotoxic T lymphocytes), demonstrating how PDT modulates the mechanical properties of cancer cells and activates T cell responses. The antitumor immunotherapeutic effect of GDYO was further evaluated in a murine xenograft model. Results: GDYO increased the mechanical stiffness of tumor cells and augmented T-cell cytotoxicity and inflammatory cytokine secretion (IFN-γ and TNF-α) under laser in vitro. Furthermore, GDYO-based PDT exerted inhibitory effects on OSCC models and elicited antitumor immune responses via specific cytotoxic T cells. Conclusion: These results highlight that GDYO is a promising candidate for OSCC therapy, shifting the mechanical forces of OSCC cells and breaking through the barriers of the immunosuppressive tumor microenvironment. Our study provides a novel perspective on nanomaterial-based antitumor therapies.

Transcriptome-wide m6A methylome analysis uncovered the changes of m6A modification in oral pre-malignant cells compared with normal oral epithelial cells.

As the most common post-transcriptional RNA modification, m6A methylation extensively regulates the structure and function of RNA. The dynamic and reversible modification of m6A is coordinated by m6A writers and erasers. m6A reader proteins recognize m6A modification on RNA, mediating different downstream biological functions. mRNA m6A modification and its corresponding regulators play an important role in cancers, but its characteristics in the precancerous stage are still unclear. In this study, we used oral precancerous DOK cells as a model to explore the characteristics of transcriptome-wide m6A modification and major m6A regulator expression in the precancerous stage compared with normal oral epithelial cell HOEC and oral cancer cell SCC-9 through MeRIP-seq and RT-PCR. Compared with HOEC cells, we found 1180 hyper-methylated and 1606 hypo-methylated m6A peaks and 354 differentially expressed mRNAs with differential m6A peaks in DOK cells. Although the change of m6A modification in DOK cells was less than that in SCC-9 cells, mRNAs with differential m6A in both cell lines were enriched into many identical GO terms and KEGG pathways. Among the 20 known m6A regulatory genes, FTO, ALKBH5, METTL3 and VIRMA were upregulated or downregulated in DOK cells, and the expression levels of 10 genes such as METTL14/16, FTO and IGF2BP2/3 were significantly changed in SCC-9 cells. Our data suggest that precancerous cells showed, to some extent, changes of m6A modification. Identifying some key m6A targets and corresponding regulators in precancerous stage may provide potential intervention targets for the prevention of cancer development through epigenetic modification in the future.

Effect of canonical NF-κB signaling pathway on the differentiation of rat dental epithelial stem cells.

BACKGROUND: Nuclear factor-κB (NF-κB), an important transcription factor, participates in many physiological and pathological processes such as growth, differentiation, organogenesis, apoptosis, inflammation, and immune response, including tooth development. However, it is still unknown whether NF-κB participates in the regulation of dental epithelial stem cells (DESCs) in postnatal rat incisors. Here, we investigated the specific differentiation regulatory mechanisms of the canonical NF-κB signaling pathway in DESCs and provided the mechanism of cross-talk involved in DESC differentiation. METHODS: After adding the activator or inhibitor of the NF-κB signaling pathway, Western blot and quantitative real-time PCR were used to analyze the expressions of amelogenesis-related genes and proteins and canonical transforming growth factor-ß (TGF-ß) signaling. In addition, we used amelogenesis induction in vitro by adding the activator or inhibitor of the NF-κB signaling pathway to the amelogenesis-induction medium, respectively. Recombinant TGF-ß was used to activate the TGF-ß pathway, and SMAD7 siRNA was used to downregulate the expression of SMAD7 in DESCs. RESULTS: We found that the expression of amelogenesis-related genes and proteins as well as TGF-ß signaling were downregulated, while SMAD7 expression was increased in NF-κB-activated DESCs. In addition, NF-κB-inhibited DESCs exhibited opposite results compared with NF-κB-activated DESCs. Furthermore, the canonical NF-κB signaling pathway suppressed the canonical TGF-ß-SMAD signaling by inducing SMAD7 expression involved in the regulation of DESC differentiation. CONCLUSIONS: These results indicate that the canonical NF-κB signaling pathway participated in the regulation of DESC differentiation, which was through upregulating SMAD7 expression and further suppressing the canonical TGF-ß-SMAD signaling pathway.

Schwann cells secrete extracellular vesicles to promote and maintain the proliferation and multipotency of hDPCs.

OBJECTIVES: Schwann cells (SCs) are the principal glial cells in peripheral nerve system, involved in neuropathies with great regenerative potential. Dental pulp cells have been reported to maintain neurogenic potential. In contrast, the regulatory role of SCs on human dental pulp cells (hDPCs) development remains undefined. MATERIALS AND METHODS: SC secretion and SC-derived extracellular vesicles (EVs) were collected and used to treat hDPCs; and proliferation and multiple differentiation of hDPCs were detected after EVs treatments. Finally, we analysed the proteomes of SC-EVs and SCs through mass spectrum. RESULTS: In this study, we found SC secretion showed a predominantly regulatory role on the development of hDPCs. Further, we identified EVs from SC secretion with similar function as SC secretion in regulating hDPCs proliferation and multipotency. And expression of transcription factor Oct4 was upregulated after treatment of both SC secretion and EVs, as well as Sox2 and Nanog. We detected abundant enrichment of Oct4 in EVs, which might be responsible for the upregulation of stem cell-related genes in hDPCs. Through proteome and western blot analysis, we found enriched TGFßs in EVs, indicating that accelerated hDPCs proliferation may be mediated by activated TGFß-Samd and TGFß-MAPK signalling. CONCLUSIONS: In summary, our study sheds light on critical regulatory ability of SC-derived EVs on hDPCs proliferation and multipotency, suggesting great implications for seeding cells used in tissue engineering.