C-Myc Expression in Oral Squamous Cell Carcinoma: Molecular Mechanisms in Cell Survival and Cancer Progression

The impact of genetic variations in retinoid X receptor alpha on the risk and prognosis of HPV-negative oral carcinoma

Oral squamous cell carcinoma (OSCC) is characterized by a high recurrence rate and poor survival. The retinoid X receptor (RXR) is a nuclear receptor that modulates a variety of biological processes related to cancer, including apoptosis, cellular adhesion, and immune function. A number of cancers exhibit aberrant expression and altered function of the RXR isoform alpha (RXRA), but the polymorphisms in the RXRA gene have not been investigated previously in patients with oral cancer. The current study examined the RXRA rs7864987 and rs3118523 genetic variants, assessed by the real-time PCR Taq-Man method, in 95 HPV-negative OSCC patients and 101 age- and sex-matched healthy controls. Kaplan-Meier analysis revealed that RXRA rs7864987 was significantly associated with worse overall survival and showed a tendency toward lower recurrence-free survival when compared with the wild-type allele carriers (combined TC+TT genotypes) to the mutant genotype CC. RXRA rs7864987, however, did not independently predict overall survival. The C allele of the RXRA rs3118523 genetic variant was associated with a reduced risk of OSCC. Our study indicates that polymorphisms of the RXRA gene may be prognostic and disease-predisposing genetic factors for OSCC. Additionally, RXRA polymorphisms might influence a potential genetic profile-based approach for retinoid therapy in OSCC.

Long non-coding RNAs PVT1, CCAT2, and TCF7L2, and miR-33 and c-Myc expression in oral squamous cell carcinoma and oral lichen planus patients

OBJECTIVE

The objective of this study was to assess the potential of TCF7L2, CCAT2, and PVT1 LncRNAs, c-Myc, and miR-33 as biomarkers for early diagnosis and differentiation of oral squamous cell carcinoma (OSCC) and premalignant lesions.

DESIGN

Bioinformatics tools, including COSMIC, GeneMANIA, PathVisio, KEGG Pathway Database, IntOGen, and WikiPathways, were used to investigate the signaling pathways of cancer-associated genes. The limma package was utilized for statistical analysis to identify Differentially Expressed Genes (DEGs) between OSCC tumor and normal samples. The regulatory microRNAs were analyzed using miRDB, miRWalk, and TargetScan. The type of cancer for analysis was selected using IntOGen. The expression levels of LncRNAs, miR-33, and c-Myc were measured by polymerase chain reaction (PCR) in 28 OLP and 30 OSCC tissue samples, compared to 30 healthy and 30 OSCC-adjacent tissue specimens as control groups. Data were analyzed using the Mann-Whitney test, receiver operating characteristic (ROC) curve, and multiple linear regression.

RESULTS

The expression of c-Myc (3.53 ± 2.78 vs 0.93 ± 0.50), PVT1 (10.94 ± 8.49 vs 0.91 ± 0.48), CCAT2 (11.77 ± 10.00 vs 0.92 ± 0.95), and TCF7L2 (6.48 ± 4.30 vs 1.27 ± 0.96) was significantly higher in OSCC samples compared to OLP (P < 0.001). Conversely, miR-33 expression was significantly lower in OSCC samples (0.24 ± 0.25 vs 4.90 ± 3.90). There was a significant correlation between c-Myc, CCAT2, PVT1, and miR-33 expression and clinicopathological characteristics of OSCC specimens. In OSCC samples, c-Myc, PVT1, CCAT2, and TCF7L2 showed a significant positive correlation with each other, while miR-33 expression was negatively correlated with the overexpression of other genes. The area under the curve (AUC) for c-Myc, PVT-1, CCAT2, miR-33, and TCF7L2 were 0.917, 1.000, 0.979, 0.006, and 0.929, respectively.

CONCLUSIONS

Our findings suggest that c-Myc and LncRNAs (TCF7L2, PVT1, and CCAT2) are upregulated and miR-33 is downregulated in OSCC compared to OLP samples. These genes may serve as potential genetic biomarkers for diagnosis and prediction of clinicopathological features of OSCC.

Exploring the therapeutic potential of lipid-based nanoparticles in the management of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a highly malignant and invasive tumor with significant mortality and morbidity. Current treatment modalities such as surgery, radiotherapy, and chemotherapy encounter significant limitations, such as poor targeting, systemic toxicity, and drug resistance. There is an urgent need for novel therapeutic strategies that offer targeted delivery, enhanced efficacy, and reduced side effects. The advent of lipid-based nanoparticles (LNPs) offers a promising tool for OSCC therapy, potentially overcoming the limitations of current therapeutic approaches. LNPs are composed of biodegradable and biocompatible lipids, which minimize the risk of toxicity and adverse effects. LNPs can encapsulate hydrophobic drugs, improving their solubility and stability in the biological environment, thereby enhancing their bioavailability. LNPs demonstrate significantly higher ability to encapsulate lipophilic drugs than other nanoparticle types. LNPs offer excellent storage stability, minimal drug leakage, and controlled drug release, making them highly effective nanoplatforms for the delivery of chemotherapeutic agents. Additionally, LNPs can be modified by complexing them with specific target ligands on their surface. This surface modification allows the active targeting of LNPs to the tumors in addition to the passive targeting mechanism. Furthermore, the PEGylation of LNPs improves their hydrophilicity and enhances their biological half-life by reducing clearance by the reticuloendothelial system. This review aims to discuss current treatment approaches and their limitations, as well as recent advancements in LNPs for better management of OSCC.

GRP78 inhibitor YUM70 upregulates 4E-BP1 and suppresses c-MYC expression and viability of oncogenic c-MYC tumors

The 78-kDa glucose regulated protein (GRP78) commonly upregulated in a wide variety of tumors is an important prognostic marker and a promising target for suppressing tumorigenesis and treatment resistance. While GRP78 is well established as a major endoplasmic reticulum (ER) chaperone with anti-apoptotic properties and a master regulator of the unfolded protein response, its new role as a regulator of oncoprotein expression is just emerging. MYC is dysregulated in about 70 % of human cancers and is the most commonly activated oncoprotein. However, despite recent advances, therapeutic targeting of MYC remains challenging. Here we identify GRP78 as a new target for suppression of MYC expression. Using multiple MYC-dependent cancer models including head and neck squamous cell carcinoma and their cisplatin-resistant clones, breast and pancreatic adenocarcinoma, our studies revealed that GRP78 knockdown by siRNA or inhibition of its activity by small molecule inhibitors (YUM70 or HA15) reduced c-MYC expression, leading to onset of apoptosis and loss of cell viability. This was observed in 2D cell culture, 3D spheroid and in xenograft models. Mechanistically, we determined that the suppression of c-MYC is at the post-transcriptional level and that YUM70 and HA15 treatment potently upregulated the eukaryotic translation inhibitor 4E-BP1, which targets eIF4E critical for c-MYC translation initiation. Furthermore, knock-down of 4E-BP1 via siRNA rescued YUM70-mediated c-MYC suppression. As YUM70 is also capable of suppressing N-MYC expression, this study offers a new approach to suppress MYC protein expression through knockdown or inhibition of GRP78.

Hepatitis C Virus (HCV) Infection: Pathogenesis, Oral Manifestations, and the Role of Direct-Acting Antiviral Therapy: A Narrative Review

Hepatitis C virus (HCV) infection is a global health concern with significant systemic implications, including a range of oral manifestations. This review aims to provide a comprehensive overview of the oral and dental pathologies related to HCV, the etiopathogenetic mechanisms linking such conditions to HCV and the impact of direct-acting antiviral (DAA) therapy. Common oral manifestations of HCV include oral lichen planus (OLP), periodontal disease, and xerostomia. The pathogenesis of these conditions involves both direct viral effects on oral tissues and indirect effects related to the immune response to HCV. Our literature analysis, using PubMed, Scopus, Web of Science, and Google Scholar, suggests that both the HCV infection and the immune response to HCV contribute to the increased prevalence of these oral diseases. The introduction of DAA therapy represents a significant advancement in HCV treatment, but its effects on oral manifestations, particularly OLP, are still under evaluation. Although a possible mechanism linking HCV to OSCC is yet to be determined, existing evidence encourages further investigation in this sense. Our findings highlight the need for established protocols for managing the oral health of patients with HCV, aiming to improve outcomes and quality of life.

Selenomethionine suppresses head and neck squamous cell carcinoma progression through TopBP1/ATR and TCAB1 signaling

OBJECTIVE

Head and neck squamous cell carcinoma (HNSCC) is a histological type of cancer originating from the head and neck. Selenium complexes have been considered as a potential treatment for HNSCC. Therefore, the present work focused on probing the mechanism of L-selenomethionine (SeMet) in HNSCC treatment.

METHODS

MTT and colony formation assays were carried out to analyze the survival rate and proliferation of HNSCC cells, respectively. TUNEL staining was performed to examine apoptosis of HNSCC cells. Additionally, qRT-PCR and Western blotting assays were performed to measure mRNA and protein levels, separately.

RESULTS

SeMet treatment significantly hindered the survival and promoted the apoptosis of HNSCC cells in a dose- and time-dependently. SeMet administration promoted expression of TopBP1, ATR, H2AX, p-ATR and γ-H2AX, and suppressed that of TCAB1. Importantly, SeMet treatment suppressed the proliferation and facilitated the apoptosis of HNSCC cells, which were partly reversed by down-regulation of TopBP1 or up-regulation of TCAB1. The activation of SeMet to TopBP1/ATR signaling was rescued by TCAB1 up-regulating, and the inhibition of SeMet to TCAB1 expression was rescued by TopBP1 silencing.

CONCLUSION

Our findings show that SeMet inhibits the proliferation of HNSCC cells and promotes their apoptosis by targeting TopBP1/ATR and TCAB1 signaling. SeMet is a potential method for HNSCC treatment.

F. Nucleatum enhances oral squamous cell carcinoma proliferation via E-cadherin/β-Catenin pathway

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) is a microbial risk factor whose presence increases the risk of oral squamous cell carcinoma (OSCC) progression. However, whether it can promote the proliferation of OSCC cells remains unknown.

METHODS

In this study, we investigated F. nucleatum effect on OSCC cell proliferation using in vitro and in vivo experiments.

RESULTS

Our results showed that F. nucleatum promoted OSCC cell proliferation, doubling the cell count after 72 h (CCK-8 assay). Cell cycle analysis revealed G2/M phase arrest. F. nucleatum interaction with CDH1 triggered phosphorylation, upregulating downstream protein β-catenin and activating cyclinD1 and Myc. Notably, F. nucleatum did not affect noncancerous cells, unrelated to CDH1 expression levels in CAL27 cells. Overexpression of phosphorylated CDH1 in 293T cells did not upregulate β-catenin and cycle-related genes. In vivo BALB/c nude experiments showed increased tumor volume and Ki-67 proliferation index after F. nucleatum intervention.

CONCLUSION

Our study suggests that F. nucleatum promotes OSCC cell proliferation through the CDH1/β-catenin pathway, advancing our understanding of its role in OSCC progression and highlighting its potential as a therapeutic target.

A concise review of the regulatory, diagnostic, and prognostic implications of HOXB-AS3 in tumors

Recent studies have reported that HOXB-AS3 (HOXB Cluster Antisense RNA 3) is an intriguing molecule with dual functionality as a long noncoding RNA (lncRNA) and putative coding peptide in tumorigenesis and progression. The significant expression alterations of HOXB-AS3 were detected in diverse cancer types and closely correlated with clinical stage and patient survival. Furthermore, HOXB-AS3 was involved in a spectrum of biological processes in solid tumors and hematological malignancies, such as stemness, lipid metabolism, migration, invasion, and tumor growth. This review comprehensively analyzes its clinical relevance for diagnosis and prognosis across human tumors and summarizes its functional role and regulatory mechanisms in different malignant tumors, including liver cancer, acute myeloid leukemia, ovarian cancer, lung cancer, endometrial carcinoma, colon cancer, and oral squamous cell carcinoma. Overall, HOXB-AS3 emerges as a promising biomarker and novel therapeutic target in multiple human tumors.

Andrographolide demonstrates anti-proliferative activity in oral cancer by promoting apoptosis, the programmed cell death process

Objectives

Andrographolide has been studied on different types of human cancer cells, but very few studies have been conducted on oral cancer. The study aimed to evaluate the anticancer potential of Andrographolide on an oral cancer cell line (KB) through in-silico network analysis and in vitro assays.

Materials and Methods

The in-silico analysis involved the determination of drug-likeness prediction, prediction of common targets between oral cancer and andrographolide, Protein-Protein Interactions (PPI), hub genes, top 10 associated pathways by Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway, gene ontology (GO), and molecular docking experiments. In vitro assays comprised MTT assay, apoptosis assay, cell cycle analysis, intracellular reactive oxygen species (ROS) measurement, mitochondrial membrane potential (MMP), anti-migration activity, and gene expressions using polymerase chain reaction (PCR).

Results

Fifteen common genes were obtained and were seen to be involved in cellular proliferation, regulation of apoptosis, migration of cells, regulation of MAPK cascade, and regulation of cell cycle. The most common genes involved in the top 10 pathways were MAPK1, MAPK8, MAPK14, and IL6 which were seen to be associated with the MAPK signaling pathway which may be the key pathway through which andrographolide may aid in treating oral cancer. In vitro assays showed anti-proliferative properties, late apoptosis, and anti-migratory properties.

Conclusion

According to the results obtained, andrographolide has shown anticancer properties and has the potential to be used as a chemotherapeutic drug. The in-silico approach used in the present study can aid as a model for future research in developing efficient cancer treatments.

Panoramic view of key cross-talks underpinning the oral squamous cell carcinoma stemness - unearthing the future opportunities

The clinical management of oral cancer is often frequented with challenges that arise from relapse, recurrence, invasion and resistance towards the cornerstone chemo and radiation therapies. The recent conceptual advancement in oncology has substantiated the role of cancer stem cells (CSC) as a predominant player of these intricacies. CSC are a sub-group of tumor population with inherent adroitness to self-renew with high plasticity. During tumor evolution, the structural and functional reprogramming persuades the cancer cells to acquire stem-cell like properties, thus presenting them with higher survival abilities and treatment resistance. An appraisal on key features that govern the stemness is of prime importance to confront the current challenges encountered in oral cancer. The nurturing niche of CSC for maintaining its stemness characteristics is thought to be modulated by complex multi-layered components encompassing neoplastic cells, extracellular matrix, acellular components, circulatory vessels, various cascading signaling molecules and stromal cells. This review focuses on recapitulating both intrinsic and extrinsic mechanisms that impart the stemness. There are contemplating evidences that demonstrate the role of transcription factors (TF) in sustaining the neoplastic stem cell's pluripotency and plasticity alongside the miRNA in regulation of crucial genes involved in the transformation of normal oral mucosa to malignancy. This review illustrates the interplay between miRNA and various known TF of oral cancer such as c-Myc, SOX, STAT, NANOG and OCT in orchestrating the stemness and resistance features. Further, the cross-talks involved in tumor micro-environment inclusive of cytokines, macrophages, extra cellular matrix, angiogenesis leading pathways and influential factors of hypoxia on tumorigenesis and CSC survival have been elucidated. Finally, external factorial influence of oral microbiome gained due to the dysbiosis is also emphasized. There are growing confirmations of the possible roles of microbiomes in the progression of oral cancer. Given this, an attempt has been made to explore the potential links including EMT and signaling pathways towards resistance and stemness. This review provides a spectrum of understanding on stemness and progression of oral cancers at various regulatory levels along with their current therapeutic knowledge. These mechanisms could be exploited for future research to expand potential treatment strategies.

Special Issue "Novel Anti-Proliferative Agents"

Cancer is a disease that can affect any organ and spread to other nearby or distant organs [...].

Identification of SEC61G as a Diagnostic and Prognostic Biomarker in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a heterogeneous malignancy originating from the oral mucosal epithelium. Detecting novel biomarkers can offer crucial information on disease aggressiveness and expected clinical outcomes for individual patients. SEC61G, an aberrantly expressed gene in various cancers, has been associated with negative clinical outcomes. However, its expression and clinical significance in OSCC is still unclear. In the present study, we investigated the SEC61G expression level in OSCC using bioinformatic and immunohistochemical analyses. Additionally, our findings revealed a significant correlation between SEC61G expression and clinicopathological characteristics, as well as a worse prognosis in OSCC patients. Notably, flow cytometry analysis on patient samples revealed that SEC61G expression was also linked to decreased immune infiltration in OSCC patients. In conclusion, our study provides evidence supporting SEC61G's role as a potential diagnostic, prognostic, and therapeutic marker in OSCC.

A Comprehensive Review of Natural Products as Therapeutic or Chemopreventive Agents against Head and Neck Squamous Cell Carcinoma Cells Using Preclinical Models

Head and neck squamous cell carcinoma (HNSCC) is a type of cancer that arises from the epithelium lining of the oral cavity, hypopharynx, oropharynx, and larynx. Despite the advancement of current treatments, including surgery, chemotherapy, and radiotherapy, the overall survival rate of patients afflicted with HNSCC remains poor. The reasons for these poor outcomes are due to late diagnoses and patient-acquired resistance to treatment. Natural products have been extensively explored as a safer and more acceptable alternative therapy to the current treatments, with numerous studies displaying their potential against HNSCC. This review highlights preclinical studies in the past 5 years involving natural products against HNSCC and explores the signaling pathways altered by these products. This review also addresses challenges and future directions of natural products as chemotherapeutic and chemoprevention agents against HNSCC.

Enriched Graphene Oxide-Polypropylene Suture Threads Buttons Modulate the Inflammatory Pathway Induced by Escherichia coli Lipopolysaccharide

Graphene oxide (GO), derived from graphene, has remarkable chemical–physical properties such as stability, strength, and thermal or electric conductivity and additionally shows antibacterial and anti-inflammatory properties. The present study aimed to evaluate the anti-inflammatory effects of polypropylene suture threads buttons (PPSTBs), enriched with two different concentrations of GO, in the modulation of the inflammatory pathway TLR4/MyD 88/NFκB p65/NLRP3 induced by the Escherichia coli (E. coli) lipopolysaccharide (LPS-E). The gene and the protein expression of inflammatory markers were evaluated in an in vitro model of primary human gingival fibroblasts (hGFs) by real-time PCR, western blotting, and immunofluorescence analysis. Both GO concentrations used in the polypropylene suture threads buttons-GO constructs (PPSTBs-GO) decreased the expression of inflammatory markers in hGFs treated with LPS-E. The hGFs morphology and adhesion on the PPSTBs-GO constructs were also visualized by inverted light microscopy, scanning electron microscopy (SEM), and real-time PCR. Together, these results suggest that enriched PPSTBs-GO modulates the inflammatory process through TLR4/MyD 88/NFκB p65/NLRP3 pathway.

MAPK Signaling Pathway in Oral Squamous Cell Carcinoma: Biological Function and Targeted Therapy

Oral squamous cell carcinoma accounts for 95% of human head and neck squamous cell carcinoma cases. It is highly malignant and aggressive, with a poor prognosis and a 5-year survival rate of <50%. In recent years, basic and clinical studies have been performed on the role of the mitogen-activated protein kinase (MAPK) signaling pathway in oral cancer. The MAPK signaling pathway is activated in over 50% of human oral cancer cases. Herein, we review research progress on the MAPK signaling pathway and its potential therapeutic mechanisms and discuss its molecular targeting to explore its potential as a therapeutic strategy for oral squamous cell carcinoma.