Hallmarks of Cancer-Related Newly Prognostic Factors of Oral Squamous Cell Carcinoma

A novel upstream transcription factor 1 target gene N4bp2l1 that regulates adipogenesis

N4BP2l1, which is highly expressed in oral squamous cell carcinoma, is associated with poor prognosis. However, N4bp2l1's role in adipogenesis remains unknown. We aimed to clarify the expression profile and transcriptional regulation of N4bp2l1 to elucidate the functions underlying the role of N4bp2l1 in adipocyte differentiation. Our results revealed that N4bp2l1 mRNA expression increased in 3T3-L1 cells in a differentiation-dependent manner. To investigate the transcriptional regulation of N4bp2l1, the 2-kb 5′ region upstream of the mouse N4bp2l1 promoter was cloned into a luciferase vector. Luciferase reporter assays indicated that USF1 induces the N4bp2l1 promoter activity. Electrophoretic mobility shift and chromatin immunoprecipitation assays confirmed that USF1 directly binds to the Ebox in the N4bp2l1 promoter. Furthermore, the expressions of adipocyte differentiation markers significantly decreased in N4bp2l1-knockdown cells compared with those in control cells. Our results demonstrated that N4bp2l1 is a novel USF1 target gene that may be involved in adipogenesis regulation.

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N4bp2l1 expression is increased in a differentiation-dependent manner in 3T3-L1.

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N4bp2l1 is a novel USF1 target gene.

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USF1 directly binds to the Ebox in the N4bp2l1 promoter.

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Inhibition of 3T3-L1 adipocyte differentiation by N4bp2l1 knockdown.

Interleukin-1beta and Caspase-3 expression serve as independent prognostic markers for metastasis and survival in oral squamous cell carcinoma

BACKGROUND

The Indian subcontinent has the highest incidence and prevalence of oral squamous cell carcinoma (OSCC). Inflammation and apoptosis are two emerging hall marks of cancer that might play a significant role in tumorigenesis and metastasis. Concurrent expression of proinflammatory cytokine (IL-1β) and executioner caspase (Caspase-3) in same OSCC tissue samples has not been reported in an Indian population.

OBJECTIVES

The present study aimed to evaluate the immunohistochemical expression of IL-1β and Caspase-3 in same OSCC tissue samples with clinicopathological correlation and survival analysis in Indian population.

METHODS

A retrospective study was conducted utilizing 40 formalin fixed paraffin embedded histologically diagnosed cases of OSCC comprising of 20 metastatic OSCC and 20 non-metastatic OSCC.

RESULTS

Increased expression of IL-1β and Caspase-3 were observed in metastatic OSCC. Correlation of expression of IL-1β and Caspase-3 with clinicopathological parameters revealed a significant association between these markers and staging, nodal status and site of the lesion.

CONCLUSION

Over expression of IL-1β and Caspase-3 was associated with advanced stage and poor survival of the patient. IL-1β overexpression showed significantly lower disease-free survival and disease specific survival as well. Overexpression of IL-1β and Caspase-3 in incisional OSCC biopsies could be considered for predicting metastasis and survival outcome.

Licochalcone A inhibits cell proliferation, migration, and invasion through regulating the PI3K/AKT signaling pathway in oral squamous cell carcinoma

Background: Oral squamous cell carcinoma (OSCC) is one of the most common cancers, with high metastasis and mortality. Licochalcone A (LCA) is a chalconoid from the root of Glycyrrhiza inflata, which has anti-tumor, anti-inflammatory, anti-angiogenesis effects in many cancers. However, the mechanism that underlies LCA regulating cell proliferation, migration, and invasion in OSCC remains poorly understood.

Methods: LY294002 or insulin-like growth factor 1 (IGF-1) were used to block or stimulate the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) pathway in OSCC cells. Cell proliferation was investigated by MTT assay and proliferating cell nuclear antigen (PCNA) protein level using Western blot. The expression of metastasis-related protein was detected via Western blot. Cell migration and invasion abilities were evaluated by trans-well assay. A murine xenograft model of OSCC was established to investigate the anti-tumor effect of LCA in vivo.

Results: Treatment of LCA inhibited cell proliferation in SCC4 and CAL-27 cells. Moreover, PI3K/AKT signaling was blocked by LY294002, and activated by IGF-1. LCA could suppress proliferation, migration, and invasion of OSCC cells, which was similar to the treatment of LY294002. In addition, LCA decreased IGF-1-induced OSCC progression. In a murine xenograft model, LCA treatment protected against tumor growth and metastasis in vivo.

Conclusions: LCA might inhibit cell proliferation, migration, and invasion through regulating the PI3K/AKT pathway in OSCC, developing a potential chemotherapeutic agent for OSCC.

Exploration of prognosis-related microRNA and transcription factor co-regulatory networks across cancer types

The study of cancer prognosis serves as an important part of cancer research. Large-scale cancer studies have identified numerous genes and microRNAs (miRNAs) associated with prognosis. These informative genes and miRNAs represent potential biomarkers to predict survival and to elucidate the molecular mechanism of tumour progression. MiRNAs and transcription factors (TFs) can work cooperatively as essential mediators of gene expression, and their dysregulation affects cancer prognosis. A panoramic view of cancer prognosis at the system level, considering the co-regulation roles of miRNA and TF, remains elusive. Here, we establish 12 prognosis-related miRNA-TF co-regulatory networks. The characteristics of prognostic target genes and their regulators in the network are depicted. Although the target genes and co-regulatory patterns exhibit cancer-specific properties, some miRNAs and TFs are highly conserved across cancers. We illustrate and interpret the roles of these conserved regulators by building a model associated with cancer hallmarks, functional enrichment analysis, network community detection, and exhaustive literature research. The elaborated system-level prognostic miRNA-TF co-regulation landscape, including the highlighted roles of conserved regulators, provides a novel and powerful insights into further biological and medical discoveries.

The Oncogenic Activity of miR-29b-1-5p Induces the Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma

Background: The relationship between miR-29b-1-5p and c-Met proto-oncogene in oral squamous cell carcinoma (OSCC) remains to be investigated. This study aimed to reveal the role of miR-29b-1-5p in the pathogenesis of OSCC using molecular and biological analyses. Methods: We investigated the expression of miR-29b-1-5p, c-Met, and markers of the epithelial-mesenchymal transition (EMT) in the tissues of 49 patients with OSCC and in human OSCC cells with different tumorigenicity. Further, we determined the effects of miR-29b-1-5p on the phenotypes of OSCC cell lines. Results: The expression levels of miR-29b-1-5p in most patients with OSCC were higher than those of the normal oral epithelium. In OSCC, upregulation of miR-29b-1-5p significantly correlated with histological grade, the EMT, and the immunohistochemical grade, indicated by c-Met expression. The prognosis was poor for patients with miR-29b-1-5p expression and coexpression of miR-29b-1-5p and c-Met. In OSCC cells exhibiting the EMT phenotype, knockdown of miR-29b-1-5p suppressed the EMT, which was recovered by enforced expression of c-Met. Further, the mRNA encoding cadherin 1 (CDH1) was a direct target of miR-29b-1-5p. Conclusions: Our results suggest that miR-29b-1-5p acts as an oncogenic miRNA that synergizes with c-Met to induce the EMT of OSCC cells.

Increased expression of lncRNA CASC9 promotes tumor progression by suppressing autophagy-mediated cell apoptosis via the AKT/mTOR pathway in oral squamous cell carcinoma

Recent studies showed that lncRNA CASC9 was upregulated and acted as an oncogene in a variety of tumors. However, the expression and biological functions of CASC9 in oral squamous cell carcinoma (OSCC) remain unknown. In this study, we found for the first time that CASC9 was remarkably upregulated in OSCC tissues and cell lines compared with paired noncancerous tissues and normal oral epithelial cells. Highly expressed CASC9 is strongly associated with tumor size, clinical stage, regional lymph node metastasis and overall survival time in OSCC patients. In vitro, CASC9 knockdown in OSCC cells SCC15 and CAL27 significantly promotes autophagy and apoptosis, while inhibiting proliferation. Moreover, the expression levels of p-AKT, p-mTOR, P62 and BCL-2 were significantly decreased, while the expression levels of BAX and the LC3BII/LC3BI ratio were increased in CASC9-knockdown SCC15 and CAL27 cells. After the addition of the AKT activator SC79 in CASC9-knockdown SCC15 and CAL27 cells, we found that the increased autophagy and apoptosis were remarkably rescued. Furthermore, the increased apoptosis was remarkably rescued in CASC9-knockdown OSCC cells treated with the autophagy inhibitor Autophinib. In addition, CASC9 depletion suppressed tumor growth in vivo. In conclusion, our findings demonstrate that lncRNA CASC9 promotes OSCC progression through enhancing cell proliferation and suppressing autophagy-mediated cell apoptosis via the AKT/mTOR pathway. CASC9 could potentially be used as a valuable biomarker for OSCC diagnosis and prognosis.

Pathway analysis of a genome‑wide association study on a long non‑coding RNA expression profile in oral squamous cell carcinoma

Long non-coding RNAs (lncRNAs) have been consistently demonstrated to be involved in oral squamous cell carcinoma (OSCC) as either tumor oncogenes or tumor suppressors. However, the underlying mechanisms of OSCC tumorigenesis and development have not yet been fully elucidated. The expression profiles of mRNAs and lncRNAs in OSCC were analyzed by a microarray assay. To verify the results of the microarray, 10 differentially expressed lncRNAs were randomly selected and measured by quantitative RT-PCR (qRT-PCR). Gene Ontology (GO) and metabolic pathway analyses were performed to analyze gene function and identify enriched pathways. Subsequently, two independent algorithms were used to predict the target genes of the lncRNAs. We identified 2,294 lncRNAs and 1,938 mRNAs that were differentially expressed in all three OSCC tissues by a microarray assay. Through the construction of co-expression networks of differentially expressed genes, 4 critical lncRNAs nodes were identified as potential key factors in the pathogenesis of OSCC. Expression of the 4 critical lncRNA nodes was not associated with age, sex, smoking or tumor location (P>0.05) but was positively correlated with clinical stage, lymphatic metastasis, distant metastasis and survival status (P<0.05). Kaplan-Meier analysis demonstrated that low expression levels of these 4 critical lncRNA nodes contributed to poor median progression-free survival (PFS) and overall survival (OS) (P<0.05). GO and pathway analyses indicated that the functions and enriched pathways of many dysregulated genes are associated with cancer. Potential target genes of dysregulated lncRNAs were enriched in 43 metabolic pathways, with cancer pathways being the primary enrichment pathways. In summary, we analyzed the profile of lncRNAs in OSCC and identified the functions and enriched metabolic pathways of both dysregulated mRNAs and the target genes of dysregulated lncRNAs, providing new insights into molecular markers and therapeutic targets for OSCC.

The Multifarious Functions of Pyruvate Kinase M2 in Oral Cancer Cells

Head and neck cancers, including oral squamous cell carcinoma (OSCC), are the sixth most common malignancies worldwide. OSCC frequently leads to oral dysfunction, which worsens a patient’s quality of life. Moreover, its prognosis remains poor. Unlike normal cells, tumor cells preferentially metabolize glucose by aerobic glycolysis. Pyruvate kinase (PK) catalyzes the final step in glycolysis, and the transition from PKM1 to PKM2 is observed in many cancer cells. However, little is known about PKM expression and function in OSCC. In this study, we investigated the expression of PKM in OSCC specimens and performed a functional analysis of human OSCC cells. We found that the PKM2/PKM1 ratio was higher in OSCC cells than in adjacent normal mucosal cells and in samples obtained from dysplasia patients. Furthermore, PKM2 expression was strongly correlated with OSCC tumor progression on immunohistochemistry. PKM2 expression was higher during cell growth, invasion, and apoptosis in HSC3 cells, which show a high energy flow and whose metabolism depends on aerobic glycolysis and oxidative phosphorylation. PKM2 expression was also associated with the production of reactive oxygen species (ROS) and integration of glutamine into lactate. Our results suggested that PKM2 has a variety of tumor progressive functions in OSCC cells.