lncRNA lnc-POP1-1 upregulated by VN1R5 promotes cisplatin resistance in head and neck squamous cell carcinoma through interaction with MCM5

The roles of lncRNAs in the development of drug resistance of oral cancers

Oral cancers are a significant global health concern, with a high incidence of treatment failure primarily due to the development of drug resistance. Long non-coding RNAs (lncRNAs) have emerged as critical regulators of gene expression, playing pivotal roles in various cellular processes, including tumor progression and response to therapy. This review explores the multifaceted roles of lncRNAs in the development of drug resistance in oral cancers. We highlight the mechanisms by which lncRNAs modulate drug efflux, apoptosis, epithelial-mesenchymal transition (EMT), and other pathways associated with chemoresistance. Key lncRNAs implicated in resistance to commonly used chemotherapeutic agents in oral cancers are discussed, along with their potential as therapeutic targets. Understanding the involvement of lncRNAs in drug resistance mechanisms offers promising avenues for overcoming treatment barriers and improving patient outcomes. This review underscores the need for further research to elucidate the precise roles of lncRNAs in oral cancer resistance and their translation into clinical interventions.

LncRNA DYNLRB2-AS1 promotes gemcitabine resistance of nasopharyngeal carcinoma by inhibiting the ubiquitination degradation of DHX9 protein

Gemcitabine (GEM) based induction chemotherapy is a standard treatment for locoregionally advanced nasopharyngeal carcinoma (NPC). However, approximately 15 % of patients are still resistant to GEM-containing chemotherapy, which leads to treatment failure. Nevertheless, the underlying mechanisms of GEM resistance remain poorly understood. Herein, based on a microarray analysis, we identified 221 dysregulated lncRNAs, of which, DYNLRB2-AS1 was one of the most upregulated lncRNAs in GEM-resistance NPC cell lines. DYNLRB2-AS1 was shown to function as contain an oncogenic lncRNA that promoted NPC GEM resistance, cell proliferation, but inhibited cell apoptosis. Mechanistically, DYNLRB2-AS1 could directly bind to the DHX9 protein and prevent its interaction with the E3 ubiquitin ligase PRPF19, and thus blocking PRPF19-mediated DHX9 degradation, which ultimately facilitated the repair of DNA damage in the presence of GEM. Clinically, higher DYNLRB2-AS1 expression indicated an unfavourable overall survival of NPC patients who received induction chemotherapy. Overall, this study identified the oncogenic lncRNA DYNLRB2-AS1 as an independent prognostic biomarker for patients with locally advanced NPC and as a potential therapeutic target for overcoming GEM chemoresistance in NPC.

Exosomal AC068768.1 enhances the proliferation, migration, and invasion of laryngeal squamous cell carcinoma through miR-139-5p/NOTCH1 axis

Objective

Long non-coding RNAs (lncRNAs) are closely associated with the pathogenesis of laryngeal squamous cell carcinoma (LSCC). This study aimed to investigate the roles of AC068768.1 in LSCC.

Methods

Exosomes were extracted by ultracentrifugation and identified by transmission electron microscopy (TEM) assay. The expression levels of mRNA and miRNA were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Cellular functions were assesses through immunofluorescence, flow cytometry, colony formation, wound healing and transwell assays. Chromatin immunoprecipitation (ChIP) and luciferase assays were conducted to verify the binding of AC068768.1 by signal transducer and activator of transcription 3 (STAT3). Xenograft assays were performed to confirm the roles of AC068768.1 in LSCC, and hematoxylin-eosin (HE) staining was applied for histological analysis.

Results

LSCC cell-derived exosomes induced M2-like tumor-associated macrophages (TAM2) polarization, which promoted the proliferation, migration, and invasion of LSCCs. Knockdown of exosomal AC068768.1 inhibited M2 polarization and suppressed LSCC aggressiveness both in vitro and in vivo. Moreover, AC068768.1 sponged miR-139-5p, inducing the upregulation of neurogenic locus notch homolog protein 1 (NOTCH1). LSCCs adapted to TAM2 polarization in the tumor microenvironment via AC068768.1-mediated activation of the NOTCH1 pathway. Additionally, NOTCH1 activated STAT3.

Conclusion

The AC068768.1/miR-139-5p/NOTCH1/STAT3 axis promotes the metastasis of LSCC. This finding may provide a novel target for LSCC therapy.

Nanodrugs based on co-delivery strategies to combat cisplatin resistance

Cisplatin (CDDP), as a broad-spectrum anticancer drug, is able to bind to DNA and inhibit cell division. Despite the widespread use of cisplatin since its discovery, cisplatin resistance developed during prolonged chemotherapy, similar to other small molecule chemotherapeutic agents, severely limits its clinical application. Cisplatin resistance in cancer cells is mainly caused by three reasons: DNA repair, decreased cisplatin uptake/increased efflux, and cisplatin inactivation. In earlier combination therapies, the emergence of multidrug resistance (MDR) in cancer cells prevented the achievement of the desired therapeutic effect even with the accurate combination of two chemotherapeutic drugs. Therefore, combination therapy using nanocarriers for co-delivery of drugs is considered to be ideal for alleviating cisplatin resistance and reducing cisplatin-related toxicity in cancer cells. This article provides an overview of the design of cisplatin nano-drugs used to combat cancer cell resistance, elucidates the mechanisms of action of cisplatin and the pathways through which cancer cells develop resistance, and finally discusses the design of drugs and related carriers that can synergistically reduce cancer resistance when combined with cisplatin.

LncRNA EIF3J-DT promotes chemoresistance in oral squamous cell carcinoma

OBJECTIVES

This study aimed to screen oral squamous cell carcinoma (OSCC) diagnostic and prognostic candidates and investigate the potential functions and mechanisms of candidates in the chemoresistance of OSCC cell lines.

MATERIALS AND METHODS

Differential expression profiling of lncRNA was performed in a large cohort of OSCC patients from the Cancer Genome Atlas database to identify OSCC diagnostic and prognostic candidates. Taxol resistance in OSCC cell lines was analyzed using MTT assay. OSCC cell lines transfected with EIF3J-DT pcDNA or siRNA were used to determine its regulatory effects on apoptosis, cell cycle distribution and autophagy using flow cytometry and western blot.

RESULTS

We identified EIF3J-DT as a candidate for OSCC diagnosis and prognosis. The expression level of EIF3J-DT in OSCC cell lines correlates with taxol resistance. EIF3J-DT silencing attenuated taxol resistance, and EIF3J-DT overexpression enhanced taxol resistance in OSCC cell lines. Silencing of EIF3J-DT reduced taxol resistance by inducing apoptosis, cell cycle arrest, and ATG14-mediated autophagy inhibition in OSCC cell lines.

CONCLUSIONS

We found that EIF3J-DT induced chemoresistance by regulating apoptosis, cell cycle, and autophagy in OSCC cell lines, which EIF3J-DT might provide a novel therapeutic approach for OSCC as well as a diagnostic and prognostic factor.

P4HA2 contributes to head and neck squamous cell carcinoma progression and EMT through PI3K/AKT signaling pathway

Head and neck squamous cell carcinoma (HNSCC) can be defined as a deadly illness with a dismal prognosis in advanced stages. Therefore, we seek to examine P4HA2 expression and effect in HNSCC, along with the underlying mechanisms. This study utilized integrated bioinformatics analyses to evaluate the P4HA2 expression pattern, prognostic implication, and probable function in HNSCC. The study conducted various in vitro experiments, including colony formation, CCK-8, flow cytometry, wound healing, and transwell assays, on the human HNSCC cell line CAL-27 to examine the involvement of P4HA2 in HNSCC progression. Moreover, western blotting was used to investigate epithelial-mesenchymal transition (EMT) markers and PI3K/AKT pathway markers to elucidate the underlying mechanisms. P4HA2 expression was significantly enhanced in HNSCC, and its overexpression was correlated to tumor aggressiveness and a poor prognosis in patients. Based on in vitro experiments, the overexpressed P4HA2 enhanced cell proliferation, migration, invasion, as well as EMT while reducing apoptosis, whereas P4HA2 silencing exhibited the reverse effect. P4HA2 overexpression enhanced PI3K/AKT phosphorylation in HNSCC cells. Moreover, LY294002 was observed to counteract the effects of upregulated P4HA2 on proliferation, migration, invasion, and EMT in HNSCC. Collectively, we indicated that P4HA2 promoted HNSCC progression and EMT via PI3K/AKT signaling pathway.

MCM5 is a Novel Therapeutic Target for Glioblastoma

Objective

MCM5 is a DNA licensing factor involved in cell proliferation and has been previously established as an excellent biomarker in a number of malignancies. Nevertheless, the role of MCM5 in GBM has not been fully clarified. The present study aimed to investigate the potential roles of MCM5 in the treatment of GBM and to elucidate its underlying mechanism, which is beneficial for developing new therapeutic strategies and predicting prognosis.

Methods

Firstly, we obtained transcriptomic and proteomic data from the TCGA and CPTAC databases on glioma patients. Employing the DeSeq2 R package, we then identified genes with joint differential expression in GBM tissues subjected to chemotherapy. To develop a prognostic risk score model, we performed univariate and multivariate Cox regression analyses. In vitro knockdown and overexpression of MCM5 were used to further investigate the biological functions of GBM cells. Additionally, we also delved into the upstream regulation of MCM5, revealing associations with several transcription factors. Finally, we investigated differences in immune cell infiltration and drug sensitivity across diverse risk groups identified in the prognostic risk model.

Results

In this study, the chemotherapy-treated GBM samples exhibited consistent alterations in 46 upregulated and 94 downregulated genes at both the mRNA and protein levels. Notably, MCM5 emerged as a gene with prognostic significance as well as potential therapeutic relevance. In vitro experiments subsequently validated the role of increased MCM5 expression in promoting GBM cell proliferation and resistance to TMZ. Correlations with transcription factors such as CREB1, CTCF, NFYB, NRF1, PBX1, TEAD1, and USF1 were discovered during upstream regulatory analysis, enriching our understanding of MCM5 regulatory mechanisms. The study additionally delves into immune cell infiltration and drug sensitivity, providing valuable insights for personalized treatment approaches.

Conclusion

This study identifies MCM5 as a key player in GBM, demonstrating its prognostic significance and potential therapeutic relevance by elucidating its role in promoting cell proliferation and resistance to chemotherapy.

Identification of cuproptosis-related lncRNAs with the significance in prognosis and immunotherapy of oral squamous cell carcinoma

Cuproptosis, a recently characterized programmed cell death mechanism, has emerged as a potential contributor to tumorigenesis, metastasis, and immune modulation. Long non-coding RNAs (lncRNAs) have demonstrated diverse regulatory roles in cancer and hold promise as biomarkers. However, the involvement and prognostic significance of cuproptosis-related lncRNAs (CRLs) in oral squamous cell carcinoma (OSCC) remain poorly understood. Based on TCGA-OSCC data, we integrated single-sample gene set enrichment analysis (ssGSEA), the LASSO algorithm, and the tumor immune dysfunction and exclusion (TIDE) algorithm. We identified 11 CRLs through differential expression, Spearman correlation, and univariate Cox regression analyses. Two distinct CRL-related subtypes were unveiled, delineating divergent survival patterns, tumor microenvironments (TME), and mutation profiles. A robust CRL-based signature (including AC107027.3, AC008011.2, MYOSLID, AC005785.1, AC019080.5, AC020558.2, AC025265.1, FAM27E3, and LINC02367) prognosticated OSCC outcomes, immunotherapy responses, and anti-tumor strategies. Superior predictive power compared to other lncRNA models was demonstrated. Functional assessments confirmed the influence of FAM27E3, LINC02367, and MYOSLID knockdown on OSCC cell behaviors. Remarkably, the CRLs-based signature maintained stability across OSCC patient subgroups, underscoring its clinical potential for survival prediction. This study elucidates CRLs' roles in TME of OSCC and establishes a potential signature for precision therapy.

LINC01134: a pivotal oncogene with promising predictive maker and therapeutic target in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents a leading and fatal malignancy within the gastrointestinal tract. Recent advancements highlight the pivotal role of long non-coding RNAs (lncRNAs) in diverse biological pathways and pathologies, particularly in tumorigenesis. LINC01134, a particular lncRNA, has attracted considerable attention due to its oncogenic potential in hepatoma. Current research underscores LINC01134's potential in augmenting the onset and progression of HCC, with notable implications in drug resistance. This review comprehensively explores the molecular functions and regulatory mechanisms of LINC01134 in HCC, offering a fresh perspective for therapeutic interventions. By delving into LINC01134's multifaceted roles, we aim to foster novel strategies in HCC management.

From odor to oncology: non-canonical odorant receptors in cancer

Odorant receptors, traditionally associated with olfaction as chemoreceptors, have been increasingly recognized for their presence and diverse functions in various non-nasal tissues throughout the body. Beyond their roles in sensory perception, emerging evidence suggests a compelling interplay between odorant receptors and cancer progression as well. Alongside the canonical GPCR odorant receptors, dysregulation of non-canonical odorant receptors such as trace amine-associated receptors (TAARs), formyl peptide receptors (FPRs), and membrane-spanning 4A family (MS4As) has been observed in various cancer types, suggesting their contributions to cancer progression. The roles of these non-canonical chemoreceptors in cancer are complex, with some receptors promoting tumorigenesis and others acting as tumor-suppressing factors upon activation, depending on the cancer type. These findings shed light on the potential of non-canonical odorant receptors as therapeutic targets and prognostic markers in cancer, inviting further exploration to unravel their precise mechanisms of action and implications in cancer biology. In this review, we provide a comprehensive overview of the intricate relationships between these chemoreceptors and various types of cancer, potentially paving the way for innovative odor-based therapeutics. Ultimately, this review discusses the potential development of novel therapeutic strategies targeting these non-canonical chemoreceptors.

SOX2-OT Binds with ILF3 to Promote Head and Neck Cancer Progression by Modulating Crosstalk between STAT3 and TGF-β Signaling

Long non-coding RNA (lncRNA) is involved in the progression of head and neck squamous cell carcinoma (HNSCC). The molecular mechanism of lncRNA SOX2-OT in HNSCC remains unclear. Therefore, we aimed to elucidate the oncogenic role of SOX2-OT in HNSCC. QRT-PCR analysis was performed in 61 pairs of HNSCC cancer tissues, adjacent normal tissues, and 68 plasma samples confirmed that lncRNA SOX2-OT was overexpressed in cancer tissues and plasma samples, which served as a poor prognostic factor for HNSCC. The FISH assay demonstrated that SOX2-OT was localized in the nucleus and cytoplasm of HNSCC cell lines. Further, the cell function assay confirmed that SOX2-OT promoted cell proliferation and metastasis in vitro and in vivo. RNA pulldown and RIP assay results revealed that SOX2-OT bonds with ILF3 in HNSCC, and the rescue assay confirmed that SOX2-OT played an oncogenic role depending on ILF3 protein expression. Ingenuity pathway analysis and Western blotting indicated that SOX2-OT regulated HNSCC progression by promoting STAT3 phosphorylation and modulating the crosstalk between STAT3 and TGF-β signaling. These results reveal evidence for the role of SOX2-OT in HNSCC progression and metastasis by binding to ILF3, which may serve as a therapeutic target and prognostic biomarker in HNSCC.

ENAH-202 promotes cancer progression in oral squamous cell carcinoma by regulating ZNF502/VIM axis

BACKGROUND

We aimed to demonstrate the regulatory effect of long non-coding RNA (lncRNA) ENAH-202 on oral squamous cell carcinoma (OSCC) development as well as its molecular mechanism.

METHODS

We detected ENAH-202 expression in OSCC tissues and cell lines by quantitative real-time PCR (qPCR). The biological function of ENAH-202 was assessed in vitro and in vivo using CCK-8, colony formation assays, transwell assays, xenograft formation, and tail vein injection. The further molecular mechanism by which ENAH-202 promoted OSCC progression was identified using RNA pull-down, LS-MS/MS analysis, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) assays.

RESULTS

ENAH-202 was significantly upregulated in OSCC tissues and cells. ENAH-202 promoted OSCC cell proliferation, migration, and invasion in vitro and in vivo. The expression of enabled homolog (ENAH) and epithelial-to-mesenchymal transition (EMT)-related proteins was changed with the expression of ENAH-202. Moreover, ENAH-202 promoted the transcription of Vimentin (VIM) by binding with ZNF502, which can help ENAH-202 promote OSCC progression.

CONCLUSIONS

ENAH-202 facilitated OSCC cell proliferation and metastasis by regulating ZNF502/VIM axis, which played an important role in OSCC progression.

Long non-coding RNA as a potential diagnostic biomarker in head and neck squamous cell carcinoma: A systematic review and meta-analysis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a group of malignancies arising from the epithelium of the head and neck. Despite efforts in treatment, results have remained unsatisfactory, and the death rate is high. Early diagnosis of HNSCC has clinical importance due to its high rates of invasion and metastasis. This systematic review and meta-analysis evaluated the diagnostic accuracy of lncRNAs in HNSCC patients.

METHODS

PubMed, ISI, SCOPUS, and EMBASE were searched for original publications published till April 2023 using MeSH terms and free keywords "long non-coding RNA" and "head and neck squamous cell carcinoma" and their expansions. The Reitsma bivariate random effect model pooled diagnostic test performance for studies that reported specificity and sensitivity; diagnostic AUC values from all trials were meta-analyzed using the random effects model with the inverse variance method.

RESULTS

The initial database search yielded 3209 articles, and 25 studies met our criteria. The cumulative sensitivity and specificity for lncRNAs in the diagnosis of HNSCC were 0.74 (95%CI: 0.68-0.7 (and 0.79 (95%CI: 0.74-0.83), respectively. The pooled AUC value for all specimen types was found to be 0.83. Using the inverse variance method, 71 individual lncRNAs yielded a pooled AUC of 0.77 (95%CI: 0.74-0.79). Five studies reported on the diagnostic accuracy of the MALAT1 lncRNA with a pooled AUC value of 0.83 (95%CI: 0.73-0.94).

CONCLUSIONS

LncRNAs could be used as diagnostic biomarkers for HNSCC, but further investigation is needed to validate clinical efficacy and elucidate mechanisms. High-throughput sequencing and bioinformatics should be used to ascertain expression profiles.

Yin Yang 1-Induced Long Noncoding RNA DUXAP9 Drives the Progression of Oral Squamous Cell Carcinoma by Blocking CDK1-Mediated EZH2 Degradation

LncRNAs play a critical role in oral squamous cell carcinoma (OSCC) progression. However, the function and detailed molecular mechanism of most lncRNAs in OSCC are not fully understood. Here, a novel nuclear-localized lncRNA, DUXAP9 (DUXAP9), that is highly expressed in OSCC is identified. A high level of DUXAP9 is positively associated with lymph node metastasis, poor pathological differentiation, advanced clinical stage, worse overall survival, and worse disease-specific survival in OSCC patients. Overexpression of DUXAP9 significantly promotes OSCC cell proliferation, migration, invasion, and xenograft tumor growth and metastasis, and upregulates N-cadherin, Vimentin, Ki67, PCNA, and EZH2 expression and downregulates E-cadherin in vitro and in vivo, whereas knockdown of DUXAP9 remarkably suppresses OSCC cell proliferation, migration, invasion, and xenograft tumor growth in vitro and in vivo in an EZH2-dependent manner. Yin Yang 1 (YY1) is found to activate the transcriptional expression of DUXAP9 in OSCC. Furthermore, DUXAP9 physically interacts with EZH2 and inhibits EZH2 degradation via the suppression of EZH2 phosphorylation, thereby blocking EZH2 translocation from the nucleus to the cytoplasm. Thus, DUXAP9 can serve as a promising target for OSCC therapy.

Proteasome inhibitor MG132 enhances the sensitivity of human OSCC cells to cisplatin via a ROS/DNA damage/p53 axis

Cis-diamine-dichloroplatinum II (cisplatin, CDDP) is a key chemotherapeutic regimen in the treatment of oral squamous cell carcinoma (OSCC). However, the therapeutic efficacy of cisplatin in OSCC may be hampered by chemoresistance. Therefore, the development of novel combination therapy strategies to overcome the limitations of CDDP is of great importance. The proteasome inhibitor MG132 exhibits anti-cancer properties against various types of cancer. However, our knowledge of its anti-cancer effects in combination with CDDP in OSCC cells remains limited. In the current study, the synergetic effects of MG132 and CDDP were evaluated in the human CAL27 OSCC cell line. CAL27 cells were treated with CDDP alone or in combination with MG132. The results showed that MG132 significantly reduced cell viability in a dose-dependent manner. Additionally, cell viability was significantly reduced in CAL27 cells treated with 0.2 µM MG132 and 2 µM CDDP compared with cells treated with MG132 or CDDP alone. In addition, MG132 significantly enhanced the CDDP-induced generation of intracellular reactive oxygen species and DNA damage in OSCC cells. Furthermore, treatment with CDDP or MG132 alone notably inhibited colony formation and proliferation of OSCC cells. However, co-treatment of OSCC cells with MG132 and CDDP further hampered colony formation and proliferation compared with cells treated with either MG132 or CDDP alone. Finally, in cells co-treated with MG132 and CDDP, the expression of p53 was markedly elevated and the p53-mediated apoptotic pathway was further activated compared with cells treated with MG132 or CDDP alone, as shown by the enhanced cell apoptosis, Bax upregulation, and Bcl-2 downregulation. Overall, the results of the current study support the synergistic anti-cancer effects of a combination of MG132 and CDDP against OSCC, thus suggesting that the combination of MG132 and CDDP may be a promising therapeutic strategy for the management of OSCC.

Identifying Oxidized Lipid Metabolism-Related LncRNAs as Prognostic Biomarkers of Head and Neck Squamous Cell Carcinoma

The relationship between oxidized lipid metabolism and the immunological function of cancer is well known. However, the functions and regulatory mechanisms of lncRNAs associated with oxidized lipid metabolism in head and neck squamous cell carcinoma (HNSCC) remain to be fully elucidated. In this study, we established an oxidized lipid metabolism-related lncRNA prognostic signature to assess the prognosis and immune infiltration of HNSCC patients. The HNSCC transcriptome was obtained from The Cancer Genome Atlas. The choice of the target genes with a relevance score greater than 10 was performed via a correlation analysis by GeneCards. Patients were categorized by risk score and generated with multivariate Cox regression, which was then validated and evaluated using the Kaplan–Meier analysis and time-dependent receiver operating characteristics (ROC). A nomogram was constructed by combining the risk score with the clinical data. We constructed a risk score with 24 oxidized lipid metabolism-related lncRNAs. The areas’ 1-, 2-, and 3-year OS under the ROC curve (AUC) were 0.765, 0.724, and 0.724, respectively. Furthermore, the nomogram clearly distinguished the survival probabilities of patients in high- and low-risk groups, between which substantial variations were revealed by immune infiltration analysis. The results supported the fact that oxidized lipid metabolism-related lncRNAs might predict prognoses and assist with differentiating amid differences in immune infiltration in HNSCC.

Long non-coding RNA SLC25A21-AS1 inhibits the development of epithelial ovarian cancer by specifically inducing PTBP3 degradation

BACKGROUND

Epithelial ovarian cancer (EOC) is a highly prevalent disease that rapidly metastasizes and has poor prognosis. Most women are in the middle or late stages when diagnosed and have low survival rates. Recently, long non-coding RNAs (lncRNAs) were recognized to play pivotal roles in the development of EOC.

METHODS

The expression of SLC25A21 antisense RNA 1 (SLC25A21-AS1) and Polypyrimidine Tract Binding Protein 3 (PTBP3) in EOC cells was assessed via qPCR. The proliferation activity of these cells was detected by EdU and Cell counting kit-8 (CCK8) assays, while the death rate of apoptotic cells and the cell cycle were detected by flow cytometry. Detection of cell transfer rate by transwell assay. Protein expression was measured through western blotting. Interactions between SLC25A21-AS1 and PTBP3 were detected through RNA immunoprecipitation (RIP), IF-FISH co-localization experiments and electrophoretic mobility shift assay (EMSA). The in vivo importance of SLC25A21-AS1 as a tumor suppressor modulator was assessed using murine xenograft models.

RESULTS

The lncRNA SLC25A21-AS1 has negligible expression in ovarian cancer tissues compared with that in normal ovarian tissues. A series of functional experiments revealed that the upregulation of SLC25A21-AS1 markedly blocked the proliferation and metastasis of EOC cells in vitro, while its downregulation had the opposite effect. Overexpression of SLC25A21-AS1 in a nude mouse model of EOC in vivo resulted in slower tumor growth and weakened metastatic potential. Moreover, SLC25A21-AS1 reduced the protein stability of PTBP3 and promoted its degradation. A series of subsequent experiments found that SLC25A21-AS1 inhibits EOC cell proliferation and metastasis by modulating PTBP3 through the ubiquitin-proteasome pathway and that the combination of SLC25A21-AS1 and PTBP3 provides the necessary conditions for the for the function to be realized.

CONCLUSIONS

Our research reveals the effect of SLC25A21-AS1 in EOC development and suggests SLC25A21-AS1 can serve as a prognostic target by promoting the degradation of PTBP3 to improve patient survival.

Nonenzymatic function of DPP4 promotes diabetes-associated cognitive dysfunction through IGF-2R/PKA/SP1/ERp29/IP3R2 pathway-mediated impairment of Treg function and M1 microglia polarization

BACKGROUND

Impairment of regulatory T (Treg) cells function is implicated in the pathogenesis of immune imbalance-mediated cognitive impairment. A complete understanding of whether and how this imbalance affect cognitive function in type 2 diabetes is lacking, and the driver affecting this imbalance remains unknown.

METHODS

We examined the impact of enzymatic and non-enzymatic function of DPP4 on Treg cell impairment, microglia polarization and diabetes-associated cognitive defects and identified its underlying mechanism in type 2 diabetic patients with cognitive impairment and in db/db mice.

RESULTS

We report that DPP4 binds to IGF2-R on Treg cell surface and activates PKA/SP1 signaling, which upregulate ERp29 expression and promote its binding to IP3R2, thereby inhibiting IP3R2 degradation and promoting mitochondria-associated ER membrane formation and mitochondria calcium overload in Tregs. This, in turn, impairs Tregs function and polarizes microglia toward a pro-inflammatory phenotype in the hippocampus and finally leads to neuroinflammation and cognitive impairment in type 2 diabetes. Importantly, inhibiting DPP4 enzymatic activity in type 2 diabetic patients or mutating DPP4 enzymatic active site in db/db mice did not reverse these changes. However, IGF-2R knockdown or blockade ameliorated these effects both in vivo and in vitro.

CONCLUSION

These findings highlight the nonenzymatic role of DPP4 in impairing Tregs function, which may facilitate the design of novel immunotherapies for diabetes-associated cognitive impairment.

LncRNA HOXA-AS2 Promotes Temozolomide Resistance in Glioblastoma by Regulated miR-302a-3p/IGF1 Axis

Background

Glioblastoma (GBM) is a highly prevalent brain tumor characterized by high rates of morbidity, recurrence, and mortality. While temozolomide (TMZ) is commonly used as a first-line treatment for this cancer, the emergence of TMZ resistance limits its utility. The long noncoding RNA HOXA-AS2 reportedly drives GBM progression, but whether it can influence therapeutic resistance to TMZ has yet to be established.

Methods

HOXA-AS2 expression was analyzed in TMZ-resistant and sensitive GBM tissue samples and cell lines by qPCR. A siRNA-based approach was used to knock down HOXA-AS2 in GBM cells, after which TMZ resistance was tested. Bioinformatics approaches were used to predict miRNA binding targets of HOXA-AS2, after which a series of luciferase reporter assay and rescue experiments with appropriate miRNA inhibitor/mimic constructs were performed to validate these predictions and to clarify the ability of HOXA-AS2 to regulate chemoresistant activity.

Results

TMZ-resistant GBM patients and cell lines exhibited increased HOXA-AS2 expression that was correlated with worse overall survival. Knocking down HOXA-AS2 increased the sensitivity of resistant GBM cells to TMZ. miR-302a-3p was identified as a HOXA-AS2 target confirmed through luciferase reporter assays and rescue experiments, and IGF1 was further identified as a confirmed miR-302a-3p target. In addition, HOXA-AS2 knockdown resulted in a corresponding drop in IGF1 expression consistent with indirect regulation mediated by miR-302a-3p.

Conclusion

In summary, these results highlight the role of HOXA-AS2 as a driver of TMZ resistance in GBM through its ability to regulate the miR-302a-3p/IGF1 signaling axis, highlighting this pathway as a promising target for the diagnosis, therapeutic sensitization, and/or treatment of affected patients.

The expression and methylation of PITX genes is associated with the prognosis of head and neck squamous cell carcinoma

Background: The PITX gene family, comprising PITX1, PITX2, and PITX3, is critical in organogenesis and has been evolutionary conserved in animals. PITX genes are associated with the advanced progression and poor prognosis of multiple cancers. However, the relationship between the PITX genes and head and neck squamous cell carcinoma (HNSC) has not been reported.

Methods: We used data from The Cancer Genome Atlas (TCGA) to analyze the association between PITX mRNA expression and clinicopathological parameters of patients with HNSC. The prognostic value of PITX genes was evaluated using the Kaplan-Meier plotter. Multivariate Cox analysis was used to screen out prognosis-associated genes to identify better prognostic indicators. The potential roles of PITX1 and PITX2 in HNSC prognosis were investigated using the protein-protein interaction (PPI) network, Gene Ontology (GO) analysis, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The correlation between PITX1 and PITX2 expression or methylation and immune cell infiltration was evaluated using the tumor-immune system interaction database (TISIDB). MethSurv was used to identify DNA methylation and its effect on HNSC prognosis.

Results:PITX genes expression was correlated with different cancers. PITX1 and PITX2 expression was lower in the patients with HNSC. In HNSC, PITX1 expression was significantly related to the clinical stage, histologic grade, and N stage, while PITX2 expression was only significantly related to the histologic grade. The high expression of PITX3 was significantly related to the histologic grade, T stage, and N stage. Survival analysis revealed that PITX genes had prognostic value in HNSC, which was supported by multivariate Cox analysis. PPI network and enrichment analysis showed that the genes interacting with PITX1 and PITX2 belonged predominantly to signaling pathways associated with DNA binding and transcription. Of the CpG DNA methylation sites in PITX1 and PITX2, 28 and 22 were related to the prognosis of HNSC, respectively. Additionally, PITX1 and PITX2 expression and methylation was associated with tumor-infiltrating lymphocytes (TILs).

Conclusion: The PITX genes were differentially expressed in patients with HNSC, highlighting their essential role in DNA methylation and tumor-infiltrating immune cell regulation, as well as overall prognostic value in HNSC.

Regulation of temozolomide resistance via lncRNAs: Clinical and biological properties of lncRNAs in gliomas (Review)

Gliomas are a primary types of intracranial malignancies and are characterized by a poor prognosis due to aggressive recurrence profiles. Temozolomide (TMZ) is an auxiliary alkylating agent that is extensively used in conjunction with surgical resection and forms the mainstay of clinical treatment strategies for gliomas. However, the frequent occurrence of TMZ resistance in clinical practice limits its therapeutic efficacy. Accumulating evidence has demonstrated that long non‑coding RNAs (lncRNAs) can play key and varied roles in glioma progression. lncRNAs have been reported to inhibit glioma progression by targeting various signaling pathways. In addition, the differential expression of lncRNAs has also been found to mediate the resistance of glioma to several chemotherapeutic agents, particularly to TMZ. The present review article therefore summarizes the findings of previous studies in an aim to report the significance and function of lncRNAs in regulating the chemoresistance of gliomas. The present review may provide further insight into the clinical treatment of gliomas.

A novel necroptosis-related LncRNA signature for prediction of prognosis and therapeutic responses of head and neck squamous cell carcinoma

Background: Long non-coding RNAs (lncRNAs) play an essential role in the occurrence and prognosis of tumors, and it has great potential as biomarkers of tumors. However, the roles of Necroptosis-related lncRNA (NRLs) in Head and neck squamous cell carcinoma (HNSCC) remain elusive. Methods: We comprehensively analyzed the gene expression and clinical information of 964 HNSCC in four cohorts. LASSO regression was utilized to construct a necroptosis-related lncRNA prognosis signature (NLPS). We used univariate and multivariate regression to assess the independent prognostic value of NLPS. Based on the optimal cut-off, patients were divided into high- and low-risk groups. In addition, the immune profile, multi-omics alteration, and pharmacological landscape of NLPS were further revealed. Results: A total of 21 NRLs associated with survival were identified by univariate regression in four cohorts. We constructed and validated a best prognostic model (NLPS). Compared to the low-risk group, patients in the high group demonstrated a more dismal prognosis. After adjusting for clinical features by multivariate analysis, NLPS still displayed independent prognostic value. Additionally, further analysis found that patients in the low-risk group showed more abundant immune cell infiltration and immunotherapy response. In contrast, patients in the high-risk group were more sensitive to multiple chemotherapeutic agents. Conclusion: As a promising tool, the establishment of NLPS provides guidance and assistance in the clinical management and personalized treatment of HNSCC.

The Long Noncoding Transcript HNSCAT1 Activates KRT80 and Triggers Therapeutic Efficacy in Head and Neck Squamous Cell Carcinoma

Head and neck squamous carcinoma (HNSC) is the most prevalent malignancy of the head and neck regions. Long noncoding RNAs (lncRNAs) are vital in tumorigenesis regulation. However, the role of lncRNAs in HNSC requires further exploration. Herein, through bioinformatic assays using The Cancer Genome Atlas (TCGA) datasets, rapid amplification of cDNA ends (RACE) assays, and RNA-FISH, we revealed that a novel cytoplasmic transcript, HNSC-associated transcript 1 (HNSCAT1, previously recognized as linc01269), was downregulated in tumor samples and advanced tumor stages and was also associated with favorable outcomes in HNSC. Overexpression of HNSCAT1 triggered treatment efficacy in HNSCs both in vivo and in vitro. More importantly, through high-throughput transcriptome analysis (RNA-seq, in NODE database, OEZ007550), we identified KRT80, a tumor suppressor in HNSC, as the target of HNSCAT1. KRT80 expression was modulated by lncRNA HNSCAT1 and presented a positive correlation in tumor samples (R = 0.52, p < 0.001). Intriguingly, we identified that miR-1245 simultaneously interacts with KRT80 and HNSCAT1, which bridges the regulatory function between KRT80 and HNSCAT1. Conclusively, our study demonstrated that lncRNA HNSCAT1 functions as a necessary tumor inhibitor in HNSC, which provides a novel mechanism of lncRNA function and provides alternative targets for the diagnosis and treatment of HNSC.

Emerging role of lncRNAs in drug resistance mechanisms in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) originates in the squamous cell lining the mucosal surfaces of the head and neck region, including the oral cavity, nasopharynx, tonsils, oropharynx, larynx, and hypopharynx. The heterogeneity, anatomical, and functional characteristics of the patient make the HNSCC a complex and difficult-to-treat disease, leading to a poor survival rate and a decreased quality of life due to the loss of important physiologic functions and aggressive surgical injury. Alteration of driver-oncogenic and tumor-suppressing lncRNAs has recently been recently in HNSCC to obtain possible biomarkers for diagnostic, prognostic, and therapeutic approaches. This review provides current knowledge about the implication of lncRNAs in drug resistance mechanisms in HNSCC. Chemotherapy resistance is a major therapeutic challenge in HNSCC in which lncRNAs are implicated. Lately, it has been shown that lncRNAs involved in autophagy induced by chemotherapy and epithelial–mesenchymal transition (EMT) can act as mechanisms of resistance to anticancer drugs. Conversely, lncRNAs involved in mesenchymal–epithelial transition (MET) are related to chemosensitivity and inhibition of invasiveness of drug-resistant cells. In this regard, long non-coding RNAs (lncRNAs) play a pivotal role in both processes and are important for cancer detection, progression, diagnosis, therapy response, and prognostic values. As the involvement of more lncRNAs is elucidated in chemoresistance mechanisms, an improvement in diagnostic and prognostic tools could promote an advance in targeted and specific therapies in precision oncology.

Long noncoding RNA lnc-H2AFV-1 promotes cell growth by regulating aberrant m6A RNA modification in HNSCC

Head and neck squamous cell carcinoma (HNSCC) is the most common malignant tumor in the oral and maxillofacial regions, and long noncoding RNAs (lncRNAs) play crucial roles in the occurrence and progression of HNSCC. The lncRNA lnc-H2AFV-1 was found to be upregulated in HNSCC tissues; however, the function of lnc-H2AFV-1 in regulating HNSCC proliferation and the potential molecular mechanism is unclear. The present study evaluated the expression of lnc-H2AFV-1 in HNSCC tissues using quantitative real-time PCR (qPCR) and associated abundant lnc-H2AFV-1 expression with tumor size. Functionally, lnc-H2AFV-1 significantly promoted the proliferation of HNSCC cells in vitro and in vivo. Quantified N6-methyladenosine (m6A) RNA methylation and dot blot assays revealed that total m6A methylation in HNSCC cells was accompanied by lnc-H2AFV-1 expression. Western blotting showed that the expression of methyltransferase-like (METTL) 3 and METTL14 was consistent with that of lnc-H2AFV-1, whereas the expression of demethylase fat mass and obesity-associated (FTO) was contrary to that of lnc-H2AFV-1. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and MeRIP-qPCR revealed that lnc-H2AFV-1 overexpression led to the elevated expression and maximal m6A methylation of intraflagellar transport (IFT) 80 in HNSCC. In addition, METTL3/14 knockdown decreased IFT80 expression. Thus, our findings suggested that lnc-H2AFV-1 might be a biomarker that alters m6A modification by regulating the m6A methylases METTL3/14 and FTO, and then mediating downstream target IFT80 to promote HNSCC progression.

Impact of Non-Coding RNAs on Chemotherapeutic Resistance in Oral Cancer

Drug resistance in oral cancer is one of the major problems in oral cancer therapy because therapeutic failure directly results in tumor recurrence and eventually in metastasis. Accumulating evidence has demonstrated the involvement of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), in processes related to the development of drug resistance. A number of studies have shown that ncRNAs modulate gene expression at the transcriptional or translational level and regulate biological processes, such as epithelial-to-mesenchymal transition, apoptosis, DNA repair and drug efflux, which are tightly associated with drug resistance acquisition in many types of cancer. Interestingly, these ncRNAs are commonly detected in extracellular vesicles (EVs) and are known to be delivered into surrounding cells. This intercellular communication via EVs is currently considered to be important for acquired drug resistance. Here, we review the recent advances in the study of drug resistance in oral cancer by mainly focusing on the function of ncRNAs, since an increasing number of studies have suggested that ncRNAs could be therapeutic targets as well as biomarkers for cancer diagnosis.