Search for the Tumor-Associated Proteins of Oral Squamous Cell Carcinoma Collected in Taiwan using Proteomics Strategy

Circular GOLPH3 RNA exerts oncogenic effects in vitro by regulating the miRNA-1299/LIF axis in oral squamous cell carcinoma

Circular RNAs, which are a novel subclass of noncoding RNAs, are reported to be involved in various biological processes. Aberrant expression of circular RNAs may promote cancer progression. The function of circular GOLPH3 RNA (circGOLPH3) in oral squamous cell carcinoma (OSCC) is unclear. In this study, the circGOLPH3 levels in OSCC cell lines were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Gain-of-function and loss-of-function experiments were performed to evaluate the roles of circGOLPH3 in OSCC. Cell counting kit 8, migration, and invasion assays were performed to determine the functions of circGOLPH3. The mechanism of circGOLPH3 in OSCC was investigated using qRT-PCR, western blotting, luciferase activity, and RNA pull-down analyses. Furthermore, the function of circGOLPH3 in vivo was evaluated. circGOLPH3 derived from GOLPH3 was mainly localized to the cytoplasm and exhibited high stability. The expression of circGOLPH3 was upregulated in OSCC cells. circGOLPH3 promoted the growth of OSCC in vitro and in vivo. Additionally, circGOLPH3 upregulated OSCC cell migration and invasion. Mechanistically, circGOLPH3 functioned as a microRNA sponge and downregulated miR-1299 expression. miR-1299 downregulated the expression of LIF by targeting its 3’-untranslated region. Inhibition of the circGOLPH3/miR-1299/LIF axis suppressed the growth, migration, and invasion of OSCC cells. These findings indicate that the circGOLPH3/miR-1299/LIF axis promotes OSCC cell growth, migration, and invasion and that this axis is a potential therapeutic target for OSCC.

Prognostic value of nicotinamide N-methyltransferase in human cancers: Evidence from a meta-analysis and database validation

Background

Previous studies indicated that dysregulated expression of nicotinamide N-methyltransferase (NNMT) contributed to the tumor progression and predicted poor prognosis in various cancers. However, there was no exact conclusion on account of the contradictory results across studies.

Methods

The relevant studies up to December 7, 2020 were searched in PubMed, Web of Science, and Embase. The association between NNMT expression and prognostic outcomes was explored, including overall survival (OS), disease-free survival (DFS), and clinicopathological features. The bioinformatics database was used to validate the findings.

Results

Thirteen retrospective studies containing 2,591 patients with cancers were included in this analysis. High NNMT expression was significantly associated with shorter OS (hazard ratio [HR] = 2.01, 95% confidence interval [CI] = 1.42–2.86, and P < 0.01) and DFS (HR = 1.59, 95% CI = 1.23–2.05, and P < 0.01) compared to low NNMT expression in cancers. Compared to patients with low NNMT expression, patients with high NNMT expression tended to have worse tumor differentiation (P = 0.03), earlier lymph node metastasis (P = 0.01), earlier distant metastasis (P = 0.02), and more advanced clinical stage (P < 0.01).

Conclusion

High NNMT expression is an unfavorable factor of various cancers. NNMT is a promising indicator to predict the prognosis of various cancers and can serve as a potential therapeutic target in various cancers.

Nicotinamide N-Methyltransferase in Head and Neck Tumors: A Comprehensive Review

The head and neck tumors (HNT) are a heterogeneous group of diseases ranging from benign to malignant lesions, with distinctive molecular and clinical behaviors. Several studies have highlighted the presence of an altered metabolic phenotype in HNT, such as the upregulation of nicotinamide N-methyltransferase (NNMT). However, its biological effects have not been completely disclosed and the role of NNMT in cancer cell metabolism remains unclear. Therefore, this comprehensive review aims to evaluate the available literature regarding the biological, diagnostic, and prognostic role of NNMT in HNT. NNMT was shown to be significantly overexpressed in all of the evaluated HNT types. Moreover, its upregulation has been correlated with cancer cell migration and adverse clinical outcomes, such as high-pathological stage, lymph node metastasis, and locoregional recurrences. However, in oral squamous cell carcinoma (OSCC) these associations are still debated, and several studies have failed to demonstrate the prognostic significance of NNMT. The shRNA-mediated gene silencing efficiently suppressed the NNMT gene expression and exhibited a clear inhibitory effect on cell proliferation, promoting the expression of apoptosis-related proteins and modulating the cell cycle. NNMT could represent a new molecular biomarker and a new target of molecular-based therapy, although further studies on larger patient cohorts are needed to explore its biological role in HNT.

Identification of potential glycoprotein biomarkers in oral squamous cell carcinoma using sweet strategies

The prevalence of oral squamous cell carcinoma (OSCC) is high in South and Southeast Asia regions. Most OSCC patients are detected at advanced stages low 5-year survival rates. Aberrant expression of glycosylated proteins was found to be associated with malignant transformation and cancer progression. Hence, identification of cancer-associated glycoproteins could be used as potential biomarkers that are beneficial for diagnosis or clinical management of patients. This study aims to identify the differentially expressed glycoproteins using lectin-based glycoproteomics approaches. Serum samples of 40 patients with OSCC, 10 patients with oral potentially malignant disorder (OPMD), and 10 healthy individuals as control group were subjected to two-dimensional gel electrophoresis (2-DE) coupled with lectin Concanavalin A and Jacalin that specifically bind to N- and O-glycosylated proteins, respectively. Five differentially expressed N- and O-glycoproteins with various potential glycosylation sites were identified, namely N-glycosylated α1-antitrypsin (AAT), α2-HS-glycoprotein (AHSG), apolipoprotein A-I (APOA1), and haptoglobin (HP); as well as O-glycosylated AHSG and clusterin (CLU). Among them, AAT and APOA1 were further validated using enzyme-linked immunosorbent assay (ELISA) (n = 120). It was found that AAT and APOA1 are significantly upregulated in OSCC and these glycoproteins are independent risk factors of OSCC. The clinical utility of AAT and APOA1 as potential biomarkers of OSCC is needed for further evaluation.

Proteomic Profile of Sorafenib Resistance in Hepatocellular Carcinoma; GRP78 Expression Is Associated With Inferior Response to Sorafenib

BACKGROUND/AIM

The outcome of patients with advanced hepatocellular carcinoma (HCC) remains poor and therapeutic options, including sorafenib, the first anti-cancer drug proved to prolong survival in patients with advanced HCC, are limited. However, no clinically useful predictive biomarker for sorafenib has been reported.

MATERIALS AND METHODS

We exploited two-dimensional gel electrophoresis coupled with mass spectrometry to find de-regulated proteins by using conditioning of a sorafenib-resistant HCC cell line, Huh7. Tumor samples from 60 patients with HCC treated with sorafenib were analyzed and correlated with survival outcome.

RESULTS

Comparative proteomics indicated three proteins including, 78 kDa glucose related protein (GRP78), 14-3-3ε, and heat shock protein 90β (HSP90β). The three proteins were over-expressed in sorafenib-resistant Huh7 cells. In HCC tumor samples from patients treated with sorafenib, 73% of tumor samples had a high expression of GRP78, 18% had high 14-3-3ε expression and 85% had high HSP90β expression. Among these, GRP78 was associated with the shortest progression-free survival of HCC patients treated with sorafenib.

CONCLUSION

GRP78 can be a predictive biomarker in HCC patients treated with sorafenib. Strategies designed to inhibit the GRP78-related pathway may overcome sorafenib resistance.

Silencing circular RNA hsa_circ_0004491 promotes metastasis of oral squamous cell carcinoma

AIMS

Oral squamous cell carcinoma (OSCC) is an oral cavity malignancy which is the eighth most common cancer. However, the molecular mechanisms underlying the pathogenesis of OSCC remain largely unknown, and effective methods for the prognosis and diagnosis of this disease are lacking. Circular RNAs (circRNAs) are widely expressed among mammals. A growing number of studies have shown that circRNA expression is altered in cancers. In this study, we investigated the role of hsa_circ_0004491 in OSCC cell migration and invasion and examined the clinical characteristics associated with its expression.

MAIN METHODS

Hsa_circ_0004491 expression was examined in 40 paired OSCC and normal tissue samples using quantitative real-time PCR (qRT-PCR). Wound healing, transwell and western blotting assays were conducted in OSCC cells up- or down-regulation of hsa_circ_0004491 to evaluate changes in cell migration, invasion and protein expression. KEYFINDINGS: qRT-PCR analysis revealed that hsa_circ_0004491 was significantly downregulated in OSCC tissues compared with paired normal tissues (P < 0.001), and this low expression was associated with lymph node metastasis (P = 0.0398; area under ROC curve = 0.7510). Hsa_circ_000449 silencing or overexpression significantly affected the invasion and migration abilities of OSCC cells. Western blotting analysis showed that EMT-related proteins expression was significantly changed after hsa_circ_000449 silencing or overexpression.

SIGNIFICANCE

The expression level of hsa_circ_0004491 affects the migration and invasion of OSCC cells. Hsa_circ_0004491 may therefore play a role in the progression of oral squamous cell carcinoma.

Peroxiredoxin Involvement in the Initiation and Progression of Human Cancer

SIGNIFICANCE

It has been proposed that cancer cells are heavily dependent on their antioxidant defenses for survival and growth. Peroxiredoxins are a family of abundant thiol-dependent peroxidases that break down hydrogen peroxide, and they have a central role in the maintenance and response of cells to alterations in redox homeostasis. As such, they are potential targets for disrupting tumor growth. Recent Advances: Genetic disruption of peroxiredoxin expression in mice leads to an increased incidence of neoplastic disease, consistent with a role for peroxiredoxins in protecting genomic integrity. In contrast, many human tumors display increased levels of peroxiredoxin expression, suggesting that strengthened antioxidant defenses provide a survival advantage for tumor progression. Peroxiredoxin inhibitors are being developed and explored as therapeutic agents in different cancer models.

CRITICAL ISSUES

It is important to complement peroxiredoxin knockout and expression studies with an improved understanding of the biological function of the peroxiredoxins. Although current results can be interpreted within the context that peroxiredoxins scavenge hydroperoxides, some peroxiredoxin family members appear to have more complex roles in regulating the response of cells to oxidative stress through protein interactions with constituents of other signaling pathways.

FUTURE DIRECTIONS

Further mechanistic information is required for understanding the role of oxidative stress in cancer, the function of peroxiredoxins in normal versus cancer cells, and for the design and testing of specific peroxiredoxin inhibitors that display selectivity to malignant cells. Antioxid. Redox Signal. 28, 591-608.

Combined effect of genetic polymorphisms of AURKA and environmental factors on oral cancer development in Taiwan

Background

Oral squamous cell carcinoma (OSCC) is the sixth and fourth most common cause of cancer death in men worldwide and in Taiwan, respectively. AURKA, which encodes a centrosome-related serine/threonine kinase, is frequently amplified and overexpressed in many human cancers, particularly advanced OSCC. We conducted a hospital-based case-control study to estimate AURKA single-nucleotide polymorphisms (SNPs) and environmental risk factors to determine OSCC susceptibility and clinicopathological characteristics.

Methodology/Principal findings

We enrolled a total of 876 OSCC patients and 1200 controls. Four SNPs of AURKA, namely rs1047972, rs2273535, rs2064863, and rs6024836, were analyzed using real-time polymerase chain reaction (PCR). Among the 1420 smokers, the AURKA polymorphism carriers with the betel nut chewing habit had a higher risk of oral cancer than AURKA wild-type (WT) carriers without the betel nut chewing habit. Patients with the AURKA rs2064863 gene had a 1.365-fold higher risk of stage III or IV OSCC (95% confidence interval [CI] 1.029–1.811) than those with the rs2064863 WT gene. Furthermore, carriers of the AURKA rs1047972/rs2273535/rs2064863 C-A-T haplotype had a 1.736-fold (95% CI 1.110–2.715) higher risk of OSCC than controls (C-T-T, the most common haplotype). Among patients with the betel quid chewing habit, carriers of other haplotypes (C-T-T, C-A-G, T-A-T, T-A-G, T-T-T, and C-T-G) had a 12.857-fold (95% CI 10.731–15.404) increased risk, and carriers of the C-A-T haplotype had the highest risk (AOR: 31.120; 95% CI 13.864–69.850) of OSCC, compared with those without the betel quid chewing who harbored other haplotypes.

Conclusions

In conclusion, betel nut chewing combined with the AURKA C-A-T haplotypes lead to a high risk of OSCC. These findings reveal a novel genetic-environmental predisposition for oral tumorigenesis.

Roles of peroxiredoxins in cancer, neurodegenerative diseases and inflammatory diseases

Peroxiredoxins (PRDXs) are antioxidant enzymes, known to catalyze peroxide reduction to balance cellular hydrogen peroxide (H₂O₂) levels, which are essential for cell signaling and metabolism and act as a regulator of redox signaling. Redox signaling is a critical component of cell signaling pathways that are involved in the regulation of cell growth, metabolism, hormone signaling, immune regulation and variety of other physiological functions. Early studies demonstrated that PRDXs regulates cell growth, metabolism and immune regulation and therefore involved in the pathologic regulator or protectant of several cancers, neurodegenerative diseases and inflammatory diseases. Oxidative stress and antioxidant systems are important regulators of redox signaling regulated diseases. In addition, thiol-based redox systems through peroxiredoxins have been demonstrated to regulate several redox-dependent process related diseases. In this review article, we will discuss recent findings regarding PRDXs in the development of diseases and further discuss therapeutic approaches targeting PRDXs. Moreover, we will suggest that PRDXs could be targets of several diseases and the therapeutic agents for targeting PRDXs may have potential beneficial effects for the treatment of cancers, neurodegenerative diseases and inflammatory diseases. Future research should open new avenues for the design of novel therapeutic approaches targeting PRDXs.

Anticancer activity of pyrithione zinc in oral cancer cells identified in small molecule screens and xenograft model: Implications for oral cancer therapy

Oral squamous cell carcinoma (OSCC) patients diagnosed in late stages have limited chemotherapeutic options, underscoring the great need for development of new anticancer agents for more effective disease management. We aimed to identify novel anticancer agents for OSCC using quantitative high throughput assays for screening six chemical libraries consisting of 5170 small molecule inhibitors. In depth characterization resulted in identification of pyrithione zinc (PYZ) as the most effective cytotoxic agent inhibiting cell proliferation and inducing apoptosis in OSCC cells in vitro. Further, treatment with PYZ reduced colony forming, migration and invasion potential of oral cancer cells in a dose-dependent manner. PYZ treatment also led to altered expression of several key components of the major signaling pathways including PI3K/AKT/mTOR and WNT/β-catenin in OSCC cells. In addition, treatment with PYZ also reduced expression of 14-3-3ζ, 14-3-3σ, cyclin D1, c-Myc and pyruvate kinase M2 (PKM2), proteins identified in our earlier studies to be involved in development and progression of OSCCs. Importantly, PYZ treatment significantly reduced tumor xenograft volume in immunocompromised NOD/SCID/Crl mice without causing apparent toxicity to normal tissues. Taken together, we demonstrate in vitro and in vivo efficacy of PYZ in OSCC. In conclusion, we identified PYZ in HTS assays and demonstrated in vitro and in vivo pre-clinical efficacy of PYZ as a novel anticancer therapeutic candidate in OSCC.

Differential regulation of protein expression in response to polyunsaturated fatty acids in the liver of apoE-knockout mice and in HepG2 cells

Background

Polyunsaturated fatty acids (PUFAs) are nutrients necessary for life. The liver is the essential metabolic center, which aids in maintaining health via diverse biological actions. In the present work, a proteomics study was conducted with an aim to provide new insights into PUFA-regulated hepatic protein expression in apoE-knockout mice. Additionally, we investigated how n-3 PUFAs influence cytokine-challenge by using HepG2 cells as a model.

Results

Through the proteomic analysis using 2-dimensional electrophoresis and mass spectrometry, we found that 28, 23, 14, and 28 hepatic proteins were up-regulated at least a two-fold difference in intensity compared with the control group in mice treated with the docosahexaenoic acid, eicosapentaenoic acid, arachidonic acid, and linoleic acid, respectively. In contrast, 12 hepatic proteins were down-regulated with a ratio value of less than 0.5 compared to their control counterparts by these four fatty acids. All of the altered proteins were then sorted according to their biochemical properties related to metabolism, redox stress/inflammation, enzymatic reactions, and miscellaneous functions. The results provide evidence that PUFAs may act as either pro-inflammatory or anti-inflammatory agents. Cytokine-challenged HepG2 cells were used to reveal the anti-inflammatory function of n-3 PUFAs. The results showed that interleukin (IL)-1β combined with IL-6 induced C-reactive protein (CRP) mRNA expression and its protein secretion by HepG2 cells. The CRP promoter activity was significantly increased in the IL-6-treated cells, whereas IL-1β alone had no effect. However, IL-1β and IL-6 acted synergistically to further enhance CRP promoter activities. Furthermore, n-3 PUFAs inhibited nuclear factor-κB (NF-κB) activation and the phosphorylation of the nuclear signal transducer and activator of transcription 3 (STAT3) during cytokine-induced CRP production.

Conclusion

This study indicates that PUFAs induced changes in the hepatic protein profile in vivo. Furthermore, n-3 PUFAs exert their anti-inflammatory properties through differential molecular mechanisms in hepatic cells. These results provide novel information regarding the roles of PUFAs in the liver at the tissue and cellular levels.

Targeting LUNX inhibits non-small cell lung cancer growth and metastasis

There remains a great need for effective therapies for lung cancer, the majority of which are non-small cell lung cancers (NSCLC). Here, we report the identification of a novel candidate therapeutic target, LUNX, as a molecule overexpressed in primary NSCLC and lymph node metastases that is associated with reduced postoperative survival. Functional studies demonstrated that LUNX overexpression promoted lung cancer cell migration and proliferation by interactions with the chaperone protein 14-3-3. Conversely, LUNX silencing disrupted primary tumor growth, local invasion, and metastatic colonization. The finding that LUNX was expressed on cell membranes prompted us to generate and characterize LUNX antibodies as a candidate therapeutic. Anti-LUNX could downregulate LUNX and reduce lung cancer cell proliferation and migration in vitro. Administered in vivo to mice bearing lung cancer xenografts, anti-LUNX could slow tumor growth and metastasis and improve mouse survival. Together, our work provides a preclinical proof of concept for LUNX as a novel candidate target for immunotherapy in lung cancer.

Nicotinamide N-methyltransferase enhances the capacity of tumorigenesis associated with the promotion of cell cycle progression in human colorectal cancer cells

Nicotinamide N-methyltransferase (NNMT), an enzyme involved in the biotransformation and detoxification of many drugs and xenobiotic compounds, has been found to be overexpressed in several malignancies, including colorectal cancer. However, the biological function of NNMT and the related mechanisms in colorectal cancer have not been elucidated. In the present study, we investigated the effects of NNMT on tumorigenesis by overexpressing NNMT in the human colorectal cancer cells line SW480 which lacks constitutive NNMT expression, and downregulating NNMT expression in HT-29 cells, which exhibit high endogenous expression of NNMT. We found that NNMT significantly accelerates cell proliferation, enhances colony formation in vitro and tumorigenicity in mice; it also inhibits apoptosis, promotes cell cycle progression, increases ATP and 1-methylnicotinamide level and decreases ROS level. We also showed that 1-methylnicotinamide accelerates cell growth, inhibits apoptosis, promotes cell cycle progression, attenuates ROS production and increases ATP level. Our results indicate that NNMT enhances the capacity of tumorigenesis associated with the inhibition of cell apoptosis and the promotion of cell cycle progression in human colorectal cancer cells and the 1-methylnicotinamide increased by NNMT mediates the cellular effects of NNMT in cells. NNMT may play a vital role in energy balance and ROS induction.

Down-regulation of nicotinamide N-methyltransferase induces apoptosis in human breast cancer cells via the mitochondria-mediated pathway

Nicotinamide N-methyltransferase (NNMT) has been found involved in cell proliferation of several malignancies. However, the functional role of NNMT in breast cancer has not been elucidated. In the present study, we showed that NNMT was selectively expressed in some breast cancer cell lines, down-regulation of NNMT expression in Bcap-37 and MDA-MB-231 cell lines by NNMT shRNA significantly inhibited cell growth in vitro, decreased tumorigenicity in mice and induced apoptosis. The silencing reciprocal effect of NNMT was confirmed by over-expressing NNMT in the MCF-7 and SK-BR-3 breast cancer cell lines which lack constitutive expression of NNMT. In addition, down-regulation of NNMT expression resulted in reducing expression of Bcl-2 and Bcl-xL, up-regulation of Bax, Puma, cleaved caspase-9, cleaved caspase-3 and cleaved PARP, increasing reactive oxygen species production and release of cytochrome c from mitochondria, and decreasing the phosphorylation of Akt and ERK1/2. These data suggest that down-regulation of NNMT induces apoptosis via the mitochondria-mediated pathway in breast cancer cells.

Gene expression in uninvolved oral mucosa of OSCC patients facilitates identification of markers predictive of OSCC outcomes

Oral and oropharyngeal squamous cell carcinomas (OSCC) are among the most common cancers worldwide, with approximately 60% 5-yr survival rate. To identify potential markers for disease progression, we used Affymetrix U133 plus 2.0 arrays to examine the gene expression profiles of 167 primary tumor samples from OSCC patients, 58 uninvolved oral mucosae from OSCC patients and 45 normal oral mucosae from patients without oral cancer, all enrolled at one of the three University of Washington-affiliated medical centers between 2003 to 2008. We found 2,596 probe sets differentially expressed between 167 tumor samples and 45 normal samples. Among 2,596 probe sets, 71 were significantly and consistently up- or down-regulated in the comparison between normal samples and uninvolved oral samples and between uninvolved oral samples and tumor samples. Cox regression analyses showed that 20 of the 71 probe sets were significantly associated with progression-free survival. The risk score for each patient was calculated from coefficients of a Cox model incorporating these 20 probe sets. The hazard ratio (HR) associated with each unit change in the risk score adjusting for age, gender, tumor stage, and high-risk HPV status was 2.7 (95% CI: 2.0–3.8, p = 8.8E-10). The risk scores in an independent dataset of 74 OSCC patients from the MD Anderson Cancer Center was also significantly associated with progression-free survival independent of age, gender, and tumor stage (HR 1.6, 95% CI: 1.1–2.2, p = 0.008). Gene Set Enrichment Analysis showed that the most prominent biological pathway represented by the 71 probe sets was the Integrin cell surface interactions pathway. In conclusion, we identified 71 probe sets in which dysregulation occurred in both uninvolved oral mucosal and cancer samples. Dysregulation of 20 of the 71 probe sets was associated with progression-free survival and was validated in an independent dataset.