Quantitative proteomic analysis of microdissected oral epithelium for cancer biomarker discovery

Screening Differentially Expressed Proteins in Areca Nut-Related Oral Squamous Cell Carcinoma Using Tandem Mass Tag Proteomics

OBJECTIVE

Areca nut chewing has been associated with a poor prognosis in oral squamous cell carcinoma (OSCC). This study seeks to identify differentially expressed proteins among areca nut-related OSCC,non-areca nut-related OSCC and adjacent normal epithelial tissues, with the aim of providing novel insights for the investigation of areca nut-related OSCC.

METHODS

Using Tandem mass tag (TMT)-based proteomic analysis, a comparative proteomic profiling was conducted among areca nut-related OSCC, non-areca nut-related OSCC, and adjacent normal epithelial tissues (n=15). GO and KEGG enrichment analyses were then employed to identify significant proteins pertinent to the pathogenesis of OSCC for further study. Western Blot (WB) and Immunohistochemistry (IHC) techniques were used to preliminary validate the expression patterns of LZTS1, MMP10, MYH6, MB, and TNNC1 among various groups (n=30).

RESULTS

27 differentially expressed proteins were identified when comparing the areca nut-related OSCC group with both the non-areca nut-related OSCC and normal epithelial tissue groups. Among these, 15 proteins were upregulated, while 12 were downregulated. LZTS1 and MMP10 were included in the upregulated proteins, whereas MYH6, MB, and TNNC1 were downregulated. WB and IHC analyses corroborated the proteomic findings, revealing consistent expression trends for these 5 proteins across the studied groups.

CONCLUSION

LZTS1, MMP10, MYH6, MB and TNNC1 emerge as promising biomarkers for assessing disease progression, prognosis, and potential targeted therapies in areca nut-related OSCC.

Label-based comparative proteomics of oral mucosal tissue to understand progression of precancerous lesions to oral squamous cell carcinoma

Introduction

Oral squamous cell carcinomas typically arise from precancerous lesions such as leukoplakia and erythroplakia. These lesions exhibit a range of histological changes from hyperplasia to dysplasia and carcinoma in situ, during their transformation to malignancy. The molecular mechanisms driving this multistage transition remain incompletely understood. To bridge this knowledge gap, our current study utilizes label based comparative proteomics to compare protein expression profiles across different histopathological grades of leukoplakia, erythroplakia, and oral squamous cell carcinoma samples, aiming to elucidate the molecular changes underlying lesion evolution.

Methodology

An 8-plex iTRAQ proteomics of 4 biological replicates from 8 clinical phenotypes of leukoplakia and erythroplakia, with hyperplasia, mild dysplasia, moderate dysplasia; along with phenotypes of well differentiated squamous cell carcinoma and moderately differentiated squamous cell carcinoma was carried out using the Orbitrap Fusion Lumos mass spectrometer. Raw files were processed with Maxquant, and statistical analysis across groups was conducted using MetaboAnalyst. Statistical tools such as ANOVA, PLS-DA VIP scoring, and correlation analysis were employed to identify differentially expressed proteins that had a linear expression variation across phenotypes of hyperplasia to cancer. Validation was done using Bioinformatic tools such as ClueGO + Cluepedia plugin in Cytoscape to extract functional annotations from gene ontology and pathway databases.

Results and discussion

A total of 2685 protein groups and 12,397 unique peptides were identified, and 61 proteins consistently exhibited valid reporter ion corrected intensities across all samples. Of these, 6 proteins showed linear varying expression across the analysed sample phenotypes. Collagen type VI alpha 2 chain (COL6A2), Fibrinogen β chain (FGB), and Vimentin (VIM) were found to have increased linear expression across pre-cancer phenotypes of leukoplakia to cancer, while Annexin A7 (ANXA7) was seen to be having a linear decreasing expression. Collagen type VI alpha 2 chain (COL6A2) and Annexin A2 (ANXA2) had increased linear expression across precancer phenotypes of erythroplakia to cancer. The mass spectrometry proteomics data have been deposited to the ProteomeXchanger Consortium via the PRIDE partner repository with the data set identifier PXD054190. These differentially expressed proteins mediate cancer progression mainly through extracellular exosome; collagen-containing extracellular matrix, hemostasis, platelet aggregation, and cell adhesion molecule binding.

Conclusion

Label-based proteomics is an ideal platform to study oral cancer progression. The differentially expressed proteins provide insights into the molecular mechanisms underlying the progression of oral premalignant lesions to malignant phenotypes. The study has translational value for early detection, risk stratification, and potential therapeutic targeting of oral premalignant lesions and in its prevention to malignant forms.

The role of cornulin (CRNN) in the progression of cutaneous squamous cell carcinoma involving AKT activation in SCL-1

Cutaneous squamous cell carcinoma (cSCC) is the second most common non-melanoma skin cancer that has been on the rise in recent times, particularly among older individuals. Cornulin (CRNN) is increasingly recognized as an oncogene involved in developing various types of tumors. However, the precise contribution to cSCC remains unclear. Our study observed a significant increase in CRNN expression in cSCC samples compared to healthy skin. CRNN expression in the SCL-1 cell line derived from cSCC was reduced, leading to a halt in cell growth during the transition from the G1 phase to the S phase. This reduction inhibits cell division, promotes cell death, and decreases cell invasion and migration. CRNN overexpression has been found to enhance cell growth and prevent cells from undergoing natural cell death, and the cancer-promoting effects of CRNN are linked to AKT activation. Using a mouse xenograft model, we demonstrated that the inhibition of CRNN led to a decline in cSCC tumor growth in a living organism, providing evidence of CRNN's involvement in cSCC occurrence and development. This study establishes a foundation for evaluating the effectiveness of CRNN in treating cSCC, enabling further investigation in this area.

Cornulin as a Key Diagnostic and Prognostic Biomarker in Cancers of the Squamous Epithelium

The prevalence of squamous cell carcinoma is increasing, and efforts that aid in an early and accurate diagnosis are crucial to improve clinical outcomes for patients. Cornulin, a squamous epithelium-specific protein, has recently garnered attention due to its implications in the progression of squamous cell carcinoma developed in several tissues. As an epidermal differentiation marker, it is involved in skin anchoring, regulating cellular proliferation, and is a putative tumor suppressor. The physiologically healthy squamous epithelium displays a considerable level of Cornulin, whereas squamous cell carcinomas have marked downregulation, suggesting that Cornulin expression levels can be utilized for the early detection and follow-up on the progression of these types of cancer. Cornulin's expression patterns in cervical cancer have been examined, and findings support the stepwise downregulation of Cornulin levels that accompanies the progression to neoplasia in the cervix. Additional studies documented a similar trend in expression in other types of cancer, such as cutaneous, esophageal, and oropharyngeal squamous cell carcinomas. The consistent and predictable pattern of Cornulin expression across several squamous cell carcinomas and its correlation with key clinicopathological parameters make it a reliable biomarker for assessing the transformation and progression events in the squamous epithelium, thus potentially contributing to the early detection, definitive diagnosis, and more favorable prognosis for these cancer patients.

Targeted protein quantitation in human body fluids by mass spectrometry

Human body fluids (biofluids) contain various proteins, some of which reflect individuals' physiological conditions or predict diseases. Therefore, the analysis of biofluids can provide substantial information on novel biomarkers for clinical diagnosis and prognosis. In the past decades, mass spectrometry (MS)-based technologies have been developed as proteomic strategies not only for the identification of protein biomarkers but also for biomarker verification/validation in body fluids for clinical applications. The main advantage of targeted MS-based methodologies is the accurate and specific simultaneous quantitation of multiple biomarkers with high sensitivity. Here, we review MS-based methodologies that are currently used for the targeted quantitation of protein components in human body fluids, especially in plasma, urine, cerebrospinal fluid, and saliva. In addition, the currently used MS-based methodologies are summarized with a specific focus on applicable clinical sample types, MS configurations, and acquisition modes.

Protein Profiling in Human Papillomavirus-Associated Cervical Carcinogenesis: Cornulin as a Biomarker for Disease Progression

Nearly 90% of cervical cancers are linked to human papillomavirus (HPV). Uncovering the protein signatures in each histological phase of cervical oncogenesis provides a path to biomarker discovery. The proteomes extracted from formalin-fixed paraffin-embedded tissues of the normal cervix, HPV16/18-associated squamous intraepithelial lesion (SIL), and squamous cell carcinoma (SCC) were compared using liquid chromatography-mass spectrometry (LC-MS). A total of 3597 proteins were identified, with 589, 550, and 1570 proteins unique to the normal cervix, SIL, and SCC groups, respectively, while 332 proteins overlapped between the three groups. In the transition from normal cervix to SIL, all 39 differentially expressed proteins were downregulated, while all 51 proteins discovered were upregulated in SIL to SCC. The binding process was the top molecular function, while chromatin silencing in the SIL vs. normal group, and nucleosome assembly in SCC vs. SIL groups was the top biological process. The PI3 kinase pathway appears crucial in initiating neoplastic transformation, while viral carcinogenesis and necroptosis are important for cell proliferation, migration, and metastasis in cervical cancer development. Annexin A2 and cornulin were selected for validation based on LC-MS results. The former was downregulated in the SIL vs. normal cervix and upregulated in the progression from SIL to SCC. In contrast, cornulin exhibited the highest expression in the normal cervix and lowest in SCC. Although other proteins, such as histones, collagen, and vimentin, were differentially expressed, their ubiquitous expression in most cells precluded further analysis. Immunohistochemical analysis of tissue microarrays found no significant difference in Annexin A2 expression between the groups. Conversely, cornulin exhibited the strongest expression in the normal cervix and lowest in SCC, supporting its role as a tumor suppressor and potential biomarker for disease progression.

Biomarkers found in the tumor interstitial fluid may help explain the differential behavior among keratinocyte carcinomas

Basal Cell Carcinomas (BCC) and cutaneous Squamous Cell Carcinomas (SCC) are the most frequent types of cancer, and both originate from the keratinocyte transformation, giving rise to the group of tumors called keratinocyte carcinomas (KC). The invasive behavior is different in each group of KC and may be influenced by their tumor microenvironment. The principal aim of the study is to characterize the protein profile of the Tumor Interstitial Fluid (TIF) of KC to evaluate changes in the microenvironment that could be associated with their different invasive and metastatic capabilities. We obtained TIF from 27 skin biopsies and conducted a label-free quantitative proteomic analysis comparing 7 BCCs, 16 SCCs, and 4 Normal Skins. A total of 2945 proteins were identified, 511 of them quantified in more than half of the samples of each tumoral type. The proteomic analysis revealed differentially expressed TIF-proteins that could explain the different metastatic behavior in both KC. In detail, the SCC samples disclosed an enrichment of proteins related to cytoskeleton, such as Stratafin and Ladinin1. Previous studies found their up-regulation positively correlated with tumor progression. Furthermore, the TIF of SCC samples was enriched with the cytokines S100A8/S100A9. These cytokines influence the metastatic output in other tumors through the activation of NF-kB signaling. According to this, we observed a significant increase in nuclear NF-kB subunit p65 in SCCs but not in BCCs. In addition, the TIF of both tumors was enriched with proteins involved in the immune response, highlighting the relevance of this process in the composition of the tumor environment. Thus, the comparison of the TIF composition of both KC provides the discovery of a new set of differential biomarkers. Among them, secreted cytokines such as S100A9 may help explain the higher aggressiveness of SCCs, while Cornulin is a specific biomarker for BCCs. Finally, the proteomic landscape of TIF provides key information on tumor growth and metastasis, which can contribute to the identification of clinically applicable biomarkers that may be used in the diagnosis of KC, as well as therapeutic targets.

Characterization of Cornulin as a Molecular Biomarker for the Progression of Oral Squamous Cell Carcinoma

Introduction It has been shown that the expression of the epidermal differentiation marker, Cornulin, declines with the progression of squamous cell carcinomas of several tissue types. Objectives This study aims to examine Cornulin expression at the cellular level in various cell lines representative of the successive progression steps of oral squamous cell carcinoma (OSCC), a major type of head and neck cancer. This can pave the way for the utilization of this novel biomarker as a diagnostic and prognostic indicator for oral cancer and help guide treatment options. Study design Western blotting was performed to measure Cornulin expression levels using standardized cell lysates from four different cell lines representing the successive steps of OSCC progression. Specifically, primary gingival keratinocytes, dysplastic oral keratinocytes (DOK), squamous cell carcinoma 25 (SCC25) cells, and Detroit 562 cells were used to represent normal oral keratinocytes, DOKs, locally invasive OSCC cells, and metastatic OSCC cells, respectively. Results Cornulin expression was found to be downregulated with the progression from normal to premalignant to malignant cells. Quantitative analysis revealed that Cornulin is significantly downregulated by 3.4 folds in DOK cells, by 23.7 folds in SCC25 cells, and by 5.2 folds in Detroit 562 cells compared to normal gingival keratinocytes. Interestingly, Cornulin was upregulated by 4.5 folds in the metastatic Detroit 562 cell line compared to the locally invasive SCC25 cells. Conclusion Altogether, Cornulin proved to be differentially expressed at the cellular level in cell lines representative of the successive steps of OSCC progression. Specifically, we documented a gradual decrease in Cornulin expression with the progression from normal to premalignant to malignant cells. Notably, there is a significant increase in the expression of Cornulin in the metastatic cell line Detroit 562 compared to the locally invasive cell line SCC25, suggesting a possible correlation with the biological behavior and unique characteristics of these two different phenotypes.

Gene of the month: Cornulin

Cornulin (CRNN) gene encodes a 495 amino acid long protein and is located on chromosome 1q21.3. Primarily, it functions as the marker of differentiation. Initially, it was found to be specific for the squamous cells of oesophagus. However, later on, several studies have revealed the presence of Cornulin downregulation in various epithelial squamous cell carcinomas of the head and neck, oesophagus and cervix and clinically associated it with worsening of cancer and the poor prognosis. Cornulin levels also showed dysregulation in other diseases such as Eczema and Psoriasis. Besides the differentiation marker, it was identified to be involved in the stress response. The studies, in psoriasis and oesophageal squamous cell carcinoma, has elucidated that the dysregulation in the Cornulin is associated with the cell cycle events such as G1/S transition. However, the actual function of Cornulin is still yet to be explored in detail.

A systematic review of proteomic biomarkers in oral squamous cell cancer

BACKGROUND

Head and neck squamous cell cancer (HNSCC) is the most common cancer associated with chewing tobacco, in the world. As this is divided in to sites and subsites, it does not make it to top 10 cancers. The most common subsite is the oral cancer. At the time of diagnosis, more than 50% of patients with oral squamous cell cancers (OSCC) had advanced disease, indicating the lack of availability of early detection and risk assessment biomarkers. The new protein biomarker development and discovery will aid in early diagnosis and treatment which lead to targeted treatment and ultimately a good prognosis.

METHODS

This systematic review was performed as per PRISMA guidelines. All relevant studies assessing characteristics of oral cancer and proteomics were considered for analysis. Only human studies published in English were included, and abstracts, incomplete articles, and cell line or animal studies were excluded.

RESULTS

A total of 308 articles were found, of which 112 were found to be relevant after exclusion. The present review focuses on techniques of cancer proteomics and discovery of biomarkers using these techniques. The signature of protein expression may be used to predict drug response and clinical course of disease and could be used to individualize therapy with such knowledge.

CONCLUSIONS

Prospective use of these markers in the clinical setting will enable early detection, prediction of response to treatment, improvement in treatment selection, and early detection of tumor recurrence for disease monitoring. However, most of these markers for OSCC are yet to be validated.

Chrysosplenol D Triggers Apoptosis through Heme Oxygenase-1 and Mitogen-Activated Protein Kinase Signaling in Oral Squamous Cell Carcinoma

Simple Summary

Oral squamous cell carcinoma (OSCC) accounts for the most malignancies. A GLO-BOCAN 2020 report estimated 377,713 new cases of oral cancer and 177,757 deaths due to oral cancer in 2020. Chrysosplenol D, a flavonol isolated from Artemisia annua L., can exert an-ticancer effects. This study investigated the anticancer property of chrysosplenol D and its un-derlying mechanism in oral squamous cell carcinoma. We observed that chrysosplenol D reduced cell viability, cell cycle arrest, apoptosis and autophagy in OSCC. Moreover, the upregulation of heme oxygenase-1 (HO-1) was found to be critical for chrysosplenol D-induced apoptotic cell death that patients with head and neck cancer had lower HO-1 expression. The findings of the present study indicated that chrysosplenol D exerts anticancer effects on OSCC by suppressing the MAPK pathway and activating HO-1 expression. Suggest that chrysosplenol D might be a potential anticancer agent for treating OSCC.

Abstract

Chrysosplenol D, a flavonol isolated from Artemisia annua L., can exert anticancer effects. This study investigated the anticancer property of chrysosplenol D and its underlying mechanism in oral squamous cell carcinoma (OSCC). We observed that chrysosplenol D reduced cell viability and caused cell cycle arrest in the G₂/M phase. The findings of annexin V/propidium iodide staining, chromatin condensation, and apoptotic-related protein expression revealed that chrysosplenol D regulated apoptosis in OSCC. Furthermore, chrysosplenol D altered the expression of the autophagy marker LC3 and other autophagy-related proteins. Phosphatidylinositol 3-kinase/protein kinase B, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase (MAPK) were downregulated by chrysosplenol D, and the inhibition of these pathways significantly enhanced chrysosplenol D-induced cleaved poly (ADP-ribose) polymerase activation. Moreover, the upregulation of heme oxygenase-1 (HO-1) was found to be critical for chrysosplenol D-induced apoptotic cell death. The analysis of clinical data from The Cancer Genome Atlas and Gene Expression Omnibus datasets revealed that patients with head and neck cancer had lower HO-1 expression than did those with no head and neck cancer. The findings of the present study indicated that chrysosplenol D exerts anticancer effects on OSCC by suppressing the MAPK pathway and activating HO-1 expression.

Identification of Salivary Proteomic Biomarkers for Oral Cancer Screening

BACKGROUND/AIM

The current study aimed to identify biomarkers for differentiating between patients with oral cancer (OC) and healthy controls (HCs) on the basis of the comprehensive proteomic analyses of saliva samples by using liquid chromatography-mass spectrometry (LC-MS/MS).

PATIENTS AND METHODS

Unstimulated saliva samples were collected from 39 patients with OC and from 31 HCs. Proteins in the saliva were comprehensively analyzed using LC-MS/MS. To differentiate between patients with OC and HCs, a multiple logistic regression model was developed for evaluating the discriminatory ability of a combination of multiple markers.

RESULTS

A total of 23 proteins were significantly differentially expressed between the patients with OC and the HCs. Six out of the 23 proteins, namely α-2-macroglobulin-like protein 1, cornulin, hemoglobin subunit β, Ig k chain V-II region Vk167, kininogen-1 and transmembrane protease serine 11D, were selected using the forward-selection method and applied to the multiple logistic regression model. The area under the curve for discriminating between patients with OC and HCs was 0.957 when the combination of the six metabolites was used (95% confidence interval=0.915-0.998; p<0.001). Furthermore, these candidate proteins did not show a stage-specific difference.

CONCLUSION

The results of the current study showed that six salivary proteins are potential non-invasive biomarkers for OC screening.

Proteomic approaches to assist in diagnosis and prognosis of oral cancer

Introduction: Oral squamous cell carcinoma (OSCC) ranks among the top 10 leading causes of cancer worldwide, with 5-year survival rate of about 50%, high lymph node metastasis, and relapse rates. The OSCC diagnosis, prognosis, and treatment are mostly based on the clinical TNM classification. There is an urgent need for the discovery of biomarkers and therapeutic targets to assist in the clinical decision-making process.Areas covered: We summarize proteomic studies of the OSCC tumor, immune microenvironment, potential liquid biopsy sites, and post-translational modifications trying to retrieve information in the discovery and verification or (pre)validation phases. The search strategy was based on the combination of MeSH terms and expert refinement.Expert opinion: Untargeted combined with targeted proteomics are strategies that provide reliable and reproducible quantitation of proteins and are the methods of choice of many groups worldwide. Undoubtedly, proteomics has been contributing to the understanding of OSCC progression and uncovers potential candidates as biomarker or therapeutic targets. Nevertheless, none of these targets are available in the clinical practice yet. The scientific community needs to overcome the limitations by investing in robust experimental designs to strengthen the value of the findings, leveraging the translation of knowledge, and further supporting clinical decisions.

Unravelling the Dermatological Potential of the Brown Seaweed Carpomitra costata

The ever-increasing interest in keeping a young appearance and healthy skin has leveraged the skincare industry. This, coupled together with the increased concern regarding the safety of synthetic products, has boosted the demand for new and safer natural ingredients. Accordingly, the aim of this study was to evaluate the dermatological potential of the brown seaweed Carpomitra costata. The antioxidant, anti-enzymatic, antimicrobial, photoprotective and anti-inflammatory properties of five C. costata fractions (F1-F5) were evaluated. The ethyl acetate fraction (F3) demonstrated the most promising results, with the best ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (EC50 of 140.1 µg/mL) and the capacity to reduce reactive oxygen species (ROS) production promoted by UVA and UVB radiation in 3T3 cells, revealing its antioxidant and photoprotective potential. This fraction also exhibited the highest anti-enzymatic capacity, inhibiting the activities of collagenase, elastase and tyrosinase (IC50 of 7.2, 4.8 and 85.9 µg/mL, respectively). Moreover, F3 showed anti-inflammatory potential, reducing TNF-α and IL-6 release induced by LPS treatment in RAW 264.7 cells. These bioactivities may be related to the presence of phenolic compounds, such as phlorotannins, as demonstrated by NMR analysis. The results highlight the potential of C. costata as a source of bioactive ingredients for further dermatological applications.

Unravelling the Dermatological Potential of the Brown Seaweed Carpomitra costata

The ever-increasing interest in keeping a young appearance and healthy skin has leveraged the skincare industry. This, coupled together with the increased concern regarding the safety of synthetic products, has boosted the demand for new and safer natural ingredients. Accordingly, the aim of this study was to evaluate the dermatological potential of the brown seaweed Carpomitra costata. The antioxidant, anti-enzymatic, antimicrobial, photoprotective and anti-inflammatory properties of five C. costata fractions (F1–F5) were evaluated. The ethyl acetate fraction (F3) demonstrated the most promising results, with the best ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (EC50 of 140.1 µg/mL) and the capacity to reduce reactive oxygen species (ROS) production promoted by UVA and UVB radiation in 3T3 cells, revealing its antioxidant and photoprotective potential. This fraction also exhibited the highest anti-enzymatic capacity, inhibiting the activities of collagenase, elastase and tyrosinase (IC50 of 7.2, 4.8 and 85.9 µg/mL, respectively). Moreover, F3 showed anti-inflammatory potential, reducing TNF-α and IL-6 release induced by LPS treatment in RAW 264.7 cells. These bioactivities may be related to the presence of phenolic compounds, such as phlorotannins, as demonstrated by NMR analysis. The results highlight the potential of C. costata as a source of bioactive ingredients for further dermatological applications.

Blood contamination in salivary diagnostics: current methods and their limitations

The use of saliva samples in clinical studies has increased. However, the diagnostic value of whole saliva is compromised in the presence of blood contamination, owing to the higher levels of analytes in blood compared with those in saliva. The aim of this study was to review the existing methods and their limitations for measuring the levels of blood contamination in saliva. A literature search was performed using Web of Science, SCOPUS, and PubMed databases and 49 articles dealing with salivary diagnostics and measurements of blood contamination were included. Five methods for measuring the degree of blood components in saliva were discussed, including "visual inspection", use of "strip for urinalysis", and detection of plasma proteins such as "hemoglobin", "albumin", and "transferrin". Each method has its limitations, and transferrin has been regarded as the most reliable and valid marker for blood contamination in saliva. However, transferrin in whole saliva may not be solely a product of blood, and its level in whole saliva can be influenced by several factors such as age, gonadal hormones, salivary flow rate, chewing performance, and oral microorganisms. In conclusion, when quantitatively analyzing whole saliva samples, the influence of blood contamination should be considered.

miR-454 performs tumor-promoting effects in oral squamous cell carcinoma via reducing NR3C2

BACKGROUND

Aberrant miRNAs expression regulates the occurrence and progression of a variety of cancers, including oral squamous cell carcinoma (OSCC). This study aims to illustrate the potential effects of miR-454/nuclear receptor subfamily 3 group C member 2 (NR3C2) on the biological behaviors of OSCC cells.

METHODS

GEO database was applied to detect and analyze the expression of miR-545 and NR3C2 in OSCC tissues. Two OSCC cell lines including CAL27 and Tca-83 were utilized to determine the function of miR-454/NR3C2 on OSCC cells biological behaviors. miR-454 and NR3C2 expressions were regulated by miR-454 mimic/inhibitor and pcDNA3.1-NR3C2/si-NR3C2, respectively. Cells biological behaviors were evaluated by cell proliferation, colony formation, and transwell assays.

RESULTS

The data collected from GEO database indicated that miR-454 expression was upregulated in OSCC tissues; however, the expression of NR3C2 assumed a downward trend. In vitro experiments, the expression trend of miR-454 in OSCC cell lines was consistent with that of the trend in tissues, and the OSCC cells growth and movement abilities significantly decreased after miR-454 depletion. Through co-transfection experiments, we explored that the abilities of OSCC cell proliferation, colony formation, invasion, and migration obviously reduced after miR-454 depletion, but these phenomena were mitigated to some extent after NR3C2 silencing.

CONCLUSION

The study illustrates that miR-454 acts as an active regulator to facilitate OSCC cells growth, colony formation, invasion, and migration by targeting NR3C2, which may afford a novel perspective and possibility for the targeted treatment of OSCC.

Affinity chromatography assisted comprehensive phosphoproteomics analysis of human saliva for lung cancer

Affinity chromatography is a powerful technology for phosphopeptide enrichment from body fluids. Saliva is a non-invasive body fluid for disease diagnosis, while few studies applied affinity enrichment for saliva phosphoproteome. In this study, we tested two kinds of affinity chromatography materials, Ti⁴⁺-IMAC (immobilized metal affinity chromatography) and CaTiO₃, for the enrichment of phosphopeptides. Through comparison, Ti⁴⁺-IMAC method was demonstrated as the superior one, which was utilized for the comprehensive analysis of salivary phosphoproteome. More than 360 phosphoproteins were specifically extracted and identified from human saliva. Ti⁴⁺-IMAC method was further applied to compare the phosphoprotein profiling in the saliva of lung cancer group and normal control group through label-free quantification. Accordingly, 477 and 699 phosphopeptides were enriched, respectively, which corresponded to 339 and 466 proteins. In total, 796 unique phosphopeptides were revealed for 517 saliva phosphoproteins. In particular, 709 phosphorylation sites were identified, among which 26 were up-regulated (>1.5) and 149 were down-regulated (<0.66) in lung cancer. Their corresponding proteins were mainly associated with cancer promotion, system disorder, and organismal injury. Our data collectively demonstrated that salivary phosphopeptides can be comprehensively characterized through Ti⁴⁺-IMAC method. These discovered phosphoprotein candidates might be used for lung cancer detection through salivary diagnostics.

Localization of Metabolites of Human Kidney Tissue with Infrared Laser-Based Selected Reaction Monitoring Mass Spectrometry Imaging and Silver-109 Nanoparticle-Based Surface Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

Infrared (IR) laser ablation-remote-electrospray ionization (LARESI) platform coupled to a tandem mass spectrometer (MS/MS) operated in selected reaction monitoring (SRM) or multiple reaction monitoring (MRM) modes was developed and employed for imaging of target metabolites in human kidney cancer tissue. SRM or MRM modes were employed to avoid artifacts that are present in full scan MS mode. Four tissue samples containing both cancerous and noncancerous regions, obtained from three patients with renal cell carcinoma (RCC), were imaged. Sixteen endogenous metabolites that were reported in the literature as varying in abundance between cancerous and noncancerous areas in various human tissues were selected for analysis. Target metabolites comprised ten amino acids, four nucleosides and nucleobases, lactate, and vitamin E. For comparison purposes, images of the same metabolites were obtained with ultraviolet (UV) desorption/ionization mass spectrometry imaging (UV-LDI-MSI) using monoisotopic silver-109 nanoparticle-enhanced target (¹⁰⁹AgNPET) in full-scan MS mode. The acquired MS images revealed differences in abundances of selected metabolites between cancerous and noncancerous regions of the kidney tissue. Importantly, the two imaging methods offered similar results. This study demonstrates the applicability of the novel ambient LARESI SRM/MRM MSI method to both investigating and discovering cancer biomarkers in human tissue.

Upregulation of tropomyosin alpha-4 chain in patients' saliva with oral squamous cell carcinoma as demonstrated by Phage display

Patients with oral squamous cell carcinoma (OSCC) present significant alterations in their saliva proteome. We have used the shotgun Phage Display (PD) technology to identify candidate proteins that were upregulated in saliva of OSCC by selecting ligands to salivary proteins from a single-chain variable fragment (scFv) PD combinatorial library. After two selection cycles, the highly reactive clone scFv-D09 was able to distinguish saliva of OSCC patients from healthy subjects by enzyme-linked immunosorbent assay (ELISA) with sensitivity and specificity of 96.67%. Additionally, the scFv-D09 clone presented a positive immunostaining for invasive malignant epithelial cells in the connective tissue, keratin pearls in the OSCC, and ducts of salivary glands. We have further identified the target protein as the tropomyosin alpha-4 chain (TPM4) by two-dimensional polyacrylamide gel electrophoresis and mass spectrometry, and its binding to the scFV-D09 was demonstrated by bioinformatics. Briefly, we have identified TPM4 as upregulated salivary protein in patients with OSCC, which plays a central role in stabilizing cytoskeleton actin filaments, probably linked with tumor tissue remodeling. Long-term longitudinal studies are needed to validate TPM4 as a potential marker of a malignant process.

Suppression of OSCC malignancy by oral glands derived-PIP identified by iTRAQ combined with 2D LC-MS/MS

Oral squamous cell carcinoma (OSCC) is the most common malignancy in head and neck cancer and a global cause of cancer-related death. Due to the poor survival rates associated with OSCC, there is a growing need to develop novel technologies and predictive biomarkers to improve disease diagnosis. The identification of new cellular targets in OSCC tumors will benefit such developments. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics analysis combined with 2-dimensional liquid chromatography and tandem mass spectrometry (2D LC-MS/MS) were used to identify differentially expressed proteins (DEPs) between tumor and normal tissues. Of the DEPs detected, the most significantly downregulated protein in OSCC tissue was prolactin-inducible protein (PIP). Clonogenic and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) experiments showed that the proliferation capacity of OSCC cells overexpressing PIP decreased due to cell cycle arrest at the G0/G1 checkpoint. Wound-healing and transwell assay further showed that PIP overexpression also reduced the migration and invasion of OSCC cells. Immunohistochemistry (IHC) was used to analyze the expression in OSCC, indicating that PIP may be secreted by glandular cells and have an inhibitory effect on OSCC cells to produce. In western blot analysis, silencing studies confirmed that PIP mediates these effects through the AKT/mitogen-activated protein kinase (MAPK) signaling axis in OSCC cells. Taken together, this study reveals PIP as a key mediator of OSCC cell growth, migration, and invasion through its effect on AKT/MAPK signaling.

Cancer Cell Derived Small Extracellular Vesicles Contribute to Recipient Cell Metastasis Through Promoting HGF/c-Met Pathway

Cancer progression is frequently caused by metastasis and leads to significantly increased mortality. Cell derived extracellular vesicles, including exosomes, in the microenvironment play key roles in cellular signal transduction, whereas their biological function in cancer metastasis and progression needs in-depth investigation. Here, we initially demonstrate that the small extracellular vesicles (sEVs) derived from highly metastatic lung cancer cells exhibited great capacity to promote the progression of recipient cells. Quantitative proteomics was employed to comprehensively decipher the proteome of cell derived sEVs and more than 1400 sEVs proteins were identified. Comparison analysis indicates that sEVs-HGF is a potential metastasis related protein and our verification data from clinical lung cancer plasma samples and in vivo experiments further confirmed the association. We found that sEVs-HGF could induce epithelial-mesenchymal transition and the coordination between HGF and c-Met was confirmed through corresponding target knockdown and kinase inhibition. Our data collectively demonstrate that cancer cell derived sEVs contribute to recipient cell metastasis through promoting HGF/c-Met pathway, which are potential targets for the prevention and treatment of cancer metastasis.

Integrated Fourier Transform Infrared Imaging and Proteomics for Identification of a Candidate Histochemical Biomarker in Bladder Cancer

Histopathological differentiation between severe urocystitis with reactive urothelial atypia and carcinoma in situ (CIS) can be difficult, particularly after a treatment that deliberately induces an inflammatory reaction, such as intravesical instillation of Bacillus Calmette-Guèrin. However, precise grading in bladder cancer is critical for therapeutic decision making and thus requires reliable immunohistochemical biomarkers. Herein, an exemplary potential biomarker in bladder cancer was identified by the novel approach of Fourier transform infrared imaging for label-free tissue annotation of tissue thin sections. Identified regions of interest are collected by laser microdissection to provide homogeneous samples for liquid chromatography-tandem mass spectrometry-based proteomic analysis. This approach afforded label-free spatial classification with a high accuracy and without interobserver variability, along with the molecular resolution of the proteomic analysis. Cystitis and invasive high-grade urothelial carcinoma samples were analyzed. Three candidate biomarkers were identified and verified by immunohistochemistry in a small cohort, including low-grade urothelial carcinoma samples. The best-performing candidate AHNAK2 was further evaluated in a much larger independent verification cohort that also included CIS samples. Reactive urothelial atypia and CIS were distinguishable on the basis of the expression of this newly identified and verified immunohistochemical biomarker, with a sensitivity of 97% and a specificity of 69%. AHNAK2 can differentiate between reactive urothelial atypia in the setting of an acute or chronic cystitis and nonmuscle invasive-type CIS.

Cornulin Is Induced in Psoriasis Lesions and Promotes Keratinocyte Proliferation via Phosphoinositide 3-Kinase/Akt Pathways

Psoriasis is a chronic inflammatory skin disease characterized by abnormal proliferation of epidermal keratinocytes and infiltration of inflammatory cells. CRNN is a major component of the cornified cell envelope and implicated in several epithelial malignancies. Here, we show that CRNN expression was increased in the lesioned epidermis from the patients with psoriasis vulgaris and skin lesions from the imiquimod (IMQ)-treated mice. Expression of CRNN in cultured keratinocytes (HEKa and HaCaT) was also induced by M5, a mixture of five pro-inflammatory cytokines (i.e., IL-17A, IL-22, IL-1α, oncostatin M, and TNF-α). Lentiviral expression of CRNN increased cell proliferation by inducing cyclin D1. Conversely, knockdown of CRNN by small interfering RNA suppressed G1/S transition and attenuated the M5-induced proliferation. In addition, CRNN overexpression increased the phosphorylation and activation of phosphoinositide 3-kinase and Akt. Inactivation of the phosphoinositide 3-kinase and Akt pathways using small interfering RNA or selective inhibitors (LY294002 and MK2206) reduced the proliferative effects of CRNN. Furthermore, topical use of anti-psoriatic calcipotriol effectively decreased expression of CRNN, inhibited the Akt activation and improved the IMQ-stimulated psoriasis-like pathologies. Taken together, these results suggest that induced expression of CRNN may contribute to the pathogenesis of psoriasis.

Salivary secretion in health and disease

Saliva is a complex fluid produced by 3 pairs of major salivary glands and by hundreds of minor salivary glands. It comprises a large variety of constituents and physicochemical properties, which are important for the maintenance of oral health. Saliva not only protects the teeth and the oropharyngeal mucosa, it also facilitates articulation of speech, and is imperative for mastication and swallowing. Furthermore, saliva plays an important role in maintaining a balanced microbiota. Thus, the multiple functions provided by saliva are essential for proper protection and functioning of the body as a whole and for the general health. A large number of diseases and medications can affect salivary secretion through different mechanisms, leading to salivary gland dysfunction and associated oral problems, including xerostomia, dental caries and fungal infections. The first part of this review article provides an updated insight into our understanding of salivary gland structure, the neural regulation of salivary gland secretion, the mechanisms underlying the formation of saliva, the various functions of saliva and factors that influence salivary secretion under normal physiological conditions. The second part focuses on how various diseases and medical treatment including commonly prescribed medications and cancer therapies can affect salivary gland structure and function. We also provide a brief insight into how to diagnose salivary gland dysfunction.

Advances of Salivary Proteomics in Oral Squamous Cell Carcinoma (OSCC) Detection: An Update

Oral cancer refers to malignancies that have higher morbidity and mortality rates due to the late stage diagnosis and no early detection of a reliable diagnostic marker, while oral squamous cell carcinoma (OSCC) is amongst the world’s top ten most common cancers. Diagnosis of cancer requires highly sensitive and specific diagnostic tools which can support untraceable hidden sites of OSCC, yet to be unleashed, for which plenty of biomarkers are identified; the most recommended biomarker detection medium for OSCC includes biological fluids, such as blood and saliva. Saliva holds a promising future in the search for new clinical biomarkers that are easily accessible, less complex, accurate, and cost effective as well as being a non-invasive technique to follow, by analysing the malignant cells’ molecular pathology obtained from saliva through proteomic, genomic and transcriptomic approaches. However, protein biomarkers provide an immense potential for developing novel marker-based assays for oral cancer, hence this current review offers an overall focus on the discovery of a panel of candidates as salivary protein biomarkers, as well as the proteomic tools used for their identification and their significance in early oral cancer detection.

Proteomic analysis of fine-needle aspiration in differential diagnosis of thyroid nodules

Thyroid nodules are common in the general population and vary widely in their propensity to harbor thyroid malignancies. The category of follicular lesion of undetermined significance, for instance, carries only a 15% risk of malignancy. The overarching aim of this work was the proteomic study of thyroid cancer because more effort needs to be placed on differentiating malignant thyroid nodules to avoid unnecessary thyroidectomy. We used 2-dimensional electrophoresis coupled to nano-liquid chromatography electrospray ionization tandem mass spectrometry, to examine fine-needle aspiration (FNA), which was easily attainable from the wash of the syringe used for classical FNA biopsy. Overall, we found 25 different proteins able to discriminate benign from malignant samples. The different expression of moesin; annexin A1 (ANXA1); cornulin (CRNN); lactate dehydrogenase; enolase; protein DJ-1; and superoxide dismutase was confirmed in FNA by enzyme-linked immunosorbent assay or Western blot. Receiver operating characteristic curves were calculated to investigate the discriminative power of our marker. The best performance in diagnosis was obtained by combining ANXA1, enolase, protein DJ-1, superoxide dismutase, and CRNN. In addition, the most highly ranked proteins, from the perspective of follicular lesion of undetermined significance, were ANXA1 and CRNN. The research of these candidate biomarkers has then been widened to other biological fluids, such as serum and whole saliva. In conclusion, we believe that when a decision by a thyroid nodule biopsy cannot be distinctly made, the combination of our biomarkers may be one of the criteria to be taken into account for the final decision, together with the identification of ANXA1 in serum and saliva.