Identification of tumor-associated proteins in oral tongue squamous cell carcinoma by proteomics

2D-DIGE-Based Proteomic Profiling with Validations Identifies Vimentin as a Secretory Biomarker Useful for Early Detection and Poor Prognosis in Oral Cancers

Oral tongue squamous cell carcinoma (OTSCC) is an aggressive cancer with high morbidity and mortality rates, despite multimodality management. There are currently no clinically relevant molecular markers that identify patients at higher risk of recurrence and failure. We undertook 2D-DIGE proteomic profiling to study the differentially expressed proteins in OTSCC evaluating their role in prognosis. 2D-DIGE coupled with tandem mass spectrometry was performed on tissues obtained from early staged OTSCC along with its paired apparently adjacent normal tissue samples (n = 10). Top upregulated protein was validated using immunohistochemistry (n = 345), comprising of retrospective early stage OTSCC (n = 150) and prospective series of oral precancers, normal, and oral cancers (n = 195). Saliva samples collected from oral cancer and precancer samples were analyzed by ELISA (n = 146). We found statistically significant differential expression in 151 proteins out of 700 proteins quantified. Top ten differentially regulated proteins were identified using mass spectrometry analysis. We found vimentin, the mesenchymal protein, to be the most upregulated protein in tongue tumor tissues compared to adjacent apparent normal tissues. Vimentin was found to be significantly overexpressed in oral precancers along with cancers compared to normal tissues. The vimentin expression correlated significantly with differentiated states of oral precancers and cancers. Vimentin was also detected at significantly higher levels in saliva collected from oral precancer and cancer patients compared to normal healthy volunteers. Validation of vimentin in an independent series of retrospective early staged OTSCC showed that the vimentin expression is significantly associated with treatment failures and poorer DFS. The vimentin expression is useful as both poor prognostic and early detection marker in oral cancer. Vimentin detection in saliva can be a diagnostic test to detect oral precancers that may have malignant potential, needing closer follow-up, and disease monitoring.

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.

Effects of inducing apoptosis and inhibiting proliferation of siRNA on polyadenylate-binding protein-interacting protein 1 in tongue cell carcinoma

BACKGROUND

It has been reported that the polyadenylate-binding protein-interacting protein 1 (PAIP1) pathway is closely connected with the progression of some malignant tumors. Here we examined the potential functional mechanism of PAIP1 in tongue squamous cell carcinoma (TSCC).

METHODS

PAIP1 was knocked down in TSCC cell lines and proliferation and apoptosis in vitro analyzed. The molecular features of TSCC were determined using quantitative proteome and succinylome analyses. The results were confirmed in the mouse model.

RESULTS

PAIP1 promoted cell proliferation and inhibited apoptosis. Its knockdown decreased Ki67 and Pcna expressions and increased Bax/Bcl2 index and Caspase-3 expression. Bioinformatics analysis for proteomics revealed that PAIP1 knockdown correlated with the changes in differential protein expression.

CONCLUSIONS

Upregulation of PAIP1 induces cell proliferation and inhibits apoptosis in TSCC; PAIP1 might be a diagnostic biomarker and a significant drug target.

Differentially expressed proteins in positive versus negative HNSCC lymph nodes

Background

Lymph node metastasis is one of the most important prognostic factors in head and neck squamous cell carcinomas (HNSCCs) and critical for delineating their treatment. However, clinical and histological criteria for the diagnosis of nodal status remain limited. In the present study, we aimed to characterize the proteomic profile of lymph node metastasis from HNSCC patients.

Methods

In the present study, we used one- and two-dimensional electrophoresis and mass spectrometry analysis to characterize the proteomic profile of lymph node metastasis from HNSCC.

Results

Comparison of metastatic and non-metastatic lymph nodes showed 52 differentially expressed proteins associated with neoplastic development and progression. The results reinforced the idea that tumors from different anatomical subsites have dissimilar behaviors, which may be influenced by micro-environmental factor including the lymphatic network. The expression pattern of heat shock proteins and glycolytic enzymes also suggested an effect of the lymph node environment in controlling tumor growth or in metabolic reprogramming of the metastatic cell. Our study, for the first time, provided direct evidence of annexin A1 overexpression in lymph node metastasis of head and neck cancer, adding information that may be useful for diagnosing aggressive disease.

Conclusions

In brief, this study contributed to our understanding of the metastatic phenotype of HNSCC and provided potential targets for diagnostic in this group of carcinomas.

Electronic supplementary material

The online version of this article (10.1186/s12920-018-0382-6) contains supplementary material, which is available to authorized users.

Novel HDAC5-interacting motifs of Tbx3 are essential for the suppression of E-cadherin expression and for the promotion of metastasis in hepatocellular carcinoma

Tbx3, a transcriptional repressor, is essential in the organogenesis of vertebrates, stem cell self-renewal and differentiation, and the carcinogenesis of multiple tumor types. However, the mechanism by which Tbx3 participates in the metastasis of hepatocellular carcinoma (HCC) remains largely unknown. In this study, we show that Tbx3 was dramatically upregulated in clinical HCC samples and that elevated expression of Tbx3 promoted cancer progression. To determine the underlying mechanism, systematic glycine scan mutagenesis and deletion assays were performed. We identified two critical motifs, ⁵⁸⁵LFSYPYT⁵⁹¹ and ⁶⁰⁴HRH⁶⁰⁶, that contribute to the repression of transcriptional activity. These motifs are also essential for Tbx3 to promote cell migration and metastasis both in vitro and in vivo via the suppression of E-cadherin expression. More importantly, Tbx3 directly interacts with HDAC5 via these motifs, and an HDAC inhibitor blocks Tbx3-mediated cell migration and the downregulation of E-cadherin in HCC. As Tbx3 is involved in the carcinogenesis of multiple types of human cancers, our findings suggest an important target for anti-cancer drug development.

A regulatory protein that represses gene activity interacts with an enzyme involved in chromosome remodeling to promote the migration and metastasis of liver cancer cells. Ming-Liang He from the City University of Hong Kong and colleagues found that levels of the T-box transcription factor Tbx3 were dramatically increased in tissue biopsies of liver tumors. They injected Tbx3-expressing human liver cancer cells into mice and saw a positive correlation between Tbx3 activity and cancer progression. By mutating and deleting parts of Tbx3, the researchers identified two particular stretches of the protein that bind histone deacetylase 5, an enzyme involved in ensuring DNA coils, are wound tight to suppress gene activity. This interaction is needed for Tbx3’s tumor-promoting function and may be targetable with drugs in order to prevent metastasis in patients with aggressive liver cancer.

The role of calgranulin B gene on the biological behavior of squamous cervical cancer in vitro and in vivo

Objective

The objective of the study was to explore the role of calgranulin B gene on the biological behavior of squamous cervical cancer.

Methods

Differential transcription in calgranulin B gene between human papillomavirus (HPV)-positive and negative cervical cancer groups was identified, and the relationship between calgranulin B gene and matrix metalloproteinase (MMP) genes were explored using The Cancer Genome Atlas database. Subsequently, the role of calgranulin B on the cell proliferation, apoptosis, invasion and migration was investigated, through overexpression and/or underexpression of calgranulin B in cervical cancer cells. In addition, the effect of calgranulin B on the growth of the cervical cancer was studied via constructing xenograft model in BALB/c nude mice that either overexpressed or underexpressed calgranulin B.

Results

Calgranulin B gene transcription in cervical cancer was highly correlated with the high-risk HPV-16 and HPV-45. In addition, overexpression of calgranulin B increased cell proliferation, invasion and migration, whereas it did not significantly affect cell apoptosis. This effect was also confirmed by calgranulin B knockdown assay. Additionally, we found that the transcription of calgranulin B gene was negatively correlated with MMP15 and MMP24 genes, but positively associated with MMP25 genes in cervical cancer. Furthermore, calgranulin B significantly promoted the growth of cervical cancer in vivo.

Conclusion

Calgranulin B promotes cell proliferation, migration and invasion of squamous cervical cancer, possibly via regulation of MMPs. Whether there are synergistic actions between calgranulin B and HPV-16/HPV-45 infection on the squamous cervical carcinogenesis or progression need further study.

Global Quantitative Proteomics reveal Deregulation of Cytoskeletal and Apoptotic Signalling Proteins in Oral Tongue Squamous Cell Carcinoma

Oral malignancies remain to have higher morbidity and mortality rates owing to the poor understanding of the carcinogenesis and the lack of early detection and diagnosis. The lack of established biomarkers for oral tongue squamous cell carcinoma (OTSCC) resulted in aggressive multi-modality management less effective. Here, we report for the first time that a panel of potential markers identified from tongue tumor samples using two-dimensional-differential-in-gel-electrophoresis (2D-DIGE). Our approach of combining 2D-DIGE with tandem mass spectrometry identified 24 candidate proteins including cofilins, myosin light chain family members, annexins, serpins, HSPs and tropomyosins, with significant differential expression in tongue carcinomas as compared with their matched adjacent normal tissues. The expression levels of the identified proteins were further validated in larger cohort of Indian samples using qPCR. Most of the differentially regulated proteins are involved in actin cytoskeletal dynamics, drug resistance, immune system, inflammation and apoptotic signalling pathways and are known to play critical role in oral tumorigenesis. Taken together, the results from present investigation provide a valuable base for understanding the development and progression of OTSCC. The validated panel of proteins may be used as potential biomarkers for early detection as well as in predicting therapeutic outcome of OTSCC.

Antitumor effects of calgranulin B internalized in human colon cancer cells

Calgranulin B is a small, calcium-binding protein expressed in neutrophils that is secreted into the tumor microenvironment in cancer cases. We previously showed that calgranulin B levels are increased in the stools of colorectal cancer patients. In patient tumor tissues, calgranulin B protein levels correlated with the presence of stromal inflammatory cells surrounding tumor cells, and calgranulin B promoter methylation was observed in both paired human tissues and colon cancer cell lines. Cell lines did not express calgranulin B, but in vitro studies showed that colon cancer cells internalized extracellular calgranulin B, while other types of cancer cells did not. Calgranulin B internalization led to reduced cell proliferation and increased apoptotic cell death. AKT and ERK signals were also increased after calgranulin B treatment, as were p53, β-catenin, E-cadherin and cleaved caspase-3 levels. Additionally, a human protein microarray identified aurora A kinase as a calgranulin B binding partner, and binding inhibited aurora A kinase activity in a dose-dependent manner. Our findings demonstrate the antitumor effects of calgranulin B in the inflammatory microenvironment and suggest that calgranulin B could be potentially efficacious in the treatment of colon cancer.

"Omics" in oral cancer: New approaches for biomarker discovery

OBJECTIVES

In this review paper, we explored the application of "omics" approaches in the study of oral cancer (OC). It will provide a better understanding of how "omics" approaches may lead to novel biomarker molecules or molecular signatures with potential value in clinical practice. A future direction of "omics"-driven research in OC is also discussed.

METHODS

Studies on "omics"-based approaches [genomics/proteomics/transcriptomics/metabolomics] were investigated for differentiating oral squamous cell carcinoma,oral sub-mucous fibrosis, oral leukoplakia, oral lichen planus, oral erythroplakia from normal cases. Electronic databases viz., PubMed, Springer, and Google Scholar were searched.

RESULTS

One eighty-one studies were included in this review. The review shows that the fields of genomics, transcriptomics, proteomics, and metabolomics-based marker identification have implemented advanced tools to screen early changes in DNA, RNA, protein, and metabolite expression in OC population.

CONCLUSIONS

It may be concluded that despite advances in OC therapy, symptomatic presentation occurs at an advanced stage, where various curative treatment options become very limited. A molecular level study is essential for detecting an OC biomarker at an early stage. Modern "Omics" strategies can potentially make a major contribution to meet this need.

Development of a Multiplexed Assay for Oral Cancer Candidate Biomarkers Using Peptide Immunoaffinity Enrichment and Targeted Mass Spectrometry

Oral cancer is one of the most common cancers worldwide, and there are currently no biomarkers approved for aiding its management. Although many potential oral cancer biomarkers have been discovered, very few have been verified in body fluid specimens in parallel to evaluate their clinical utility. The lack of appropriate multiplexed assays for chosen targets represents one of the bottlenecks to achieving this goal. In the present study, we develop a peptide immunoaffinity enrichment-coupled multiple reaction monitoring-mass spectrometry (SISCAPA-MRM) assay for verifying multiple reported oral cancer biomarkers in saliva. We successfully produced 363 clones of mouse anti-peptide monoclonal antibodies (mAbs) against 36 of 49 selected targets, and characterized useful mAbs against 24 targets in terms of their binding affinity for peptide antigens and immuno-capture ability. Comparative analyses revealed that an equilibrium dissociation constant (K_D ) cut-off value < 2.82 × 10^-9 m could identify most clones with an immuno-capture recovery rate >5%. Using these mAbs, we assembled a 24-plex SISCAPA-MRM assay and optimized assay conditions in a 25-μg saliva matrix background. This multiplexed assay showed reasonable precision (median coefficient of variation, 7.16 to 32.09%), with lower limits of quantitation (LLOQ) of <10, 10-50, and >50 ng/ml for 14, 7 and 3 targets, respectively. When applied to a model saliva sample pooled from oral cancer patients, this assay could detect 19 targets at higher salivary levels than their LLOQs. Finally, we demonstrated the utility of this assay for quantification of multiple targets in individual saliva samples (20 healthy donors and 21 oral cancer patients), showing that levels of six targets were significantly altered in cancer compared with the control group. We propose that this assay could be used in future studies to compare the clinical utility of multiple oral cancer biomarker candidates in a large cohort of saliva samples.

The proteomic profile of a mouse model of proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) develops as a complication of retinal detachment surgery and represents a devastating condition leading to serious vision loss. A good animal model that permits extensive functional studies and drug testing is crucial in finding better therapeutic modalities for PVR. A previously established mouse model, using dispase injection, was analyzed from the proteomic point of view, examining global protein profile changes by 2D electrophoresis, image analysis and HPLC–tandem mass spectrometry‐based protein identification. The easy applicability of the mouse model was used to study the role of transglutaminase 2 (TG2) in PVR formation by proteomic examination of dispase‐induced TG2 knockout vitreous samples. Our data demonstrate that, despite the altered appearance of crystallin proteins, the lack of TG2 did not prevent the development of PVR.

Proteomics investigation of OSCC-specific salivary biomarkers in a Hungarian population highlights the importance of identification of population-tailored biomarkers

Oral squamous cell carcinoma (OSCC) accounting for about 90% of malignant oral lesions is the 6th most common malignancy worldwide. Diagnostic delay may contribute to dismal survival rate therefore, there is a need for developing specific and sensitive biomarkers to improve early detection. Hungarian population occupies the top places of statistics regarding OSCC incidence and mortality figures therefore, we aimed at finding potential salivary protein biomarkers suitable for the Hungarian population. In this study we investigated 14 proteins which were previously reported as significantly elevated in saliva of patients with OSCC. In case of IL-1α, IL-1β, IL-6, IL-8, TNF-α and VEGF a Luminex-based multiplex kit was utilized and the salivary concentrations were determined. In case of catalase, profilin-1, S100A9, CD59, galectin-3-bindig protein, CD44, thioredoxin and keratin-19, SRM-based targeted proteomic method was developed and the relative amount of the proteins was determined in the saliva of patients with OSCC and controls. After several rounds of optimization and using stable isotope-containing peptides, we developed an SRM-based method for rapid salivary protein detection. The validation of the selected potential biomarkers by ELISA revealed salivary protein S100A9 and IL-6 as useful protein biomarkers for OSCC detection improving the diagnostic accuracy for OSCC in the Hungarian population.A noninvasive diagnostic method to detect biomarkers useful for the early diagnosis of OSCC was developed. This can be an attractive strategy in screening saliva samples collected in a nation-wide multi-centric study in order to decrease morbidity, mortality, to enhance survival rate and to improve quality of life. The heterogeneity of protein biomarkers found in different ethnic groups presented in the literature highlights the importance of identification of population-tailored protein biomarkers.

Proteomic profiling of fetal esophageal epithelium, esophageal cancer, and tumor-adjacent esophageal epithelium and immunohistochemical characterization of a representative differential protein, PRX6

AIM

To understand the molecular mechanism of esophageal cancer development and provide molecular markers for screening high-risk populations and early diagnosis.

METHODS

Two-dimensional electrophoresis combined with mass spectrometry were adopted to screen differentially expressed proteins in nine cases of fetal esophageal epithelium, eight cases of esophageal cancer, and eight cases of tumor-adjacent normal esophageal epithelium collected from fetuses of different gestational age, or esophageal cancer patients from a high-risk area of esophageal cancer in China. Immunohistochemistry (avidin-biotin-horseradish peroxidase complex method) was used to detect the expression of peroxiredoxin (PRX)6 in 91 cases of esophageal cancer, tumor-adjacent normal esophageal tissue, basal cell hyperplasia, dysplasia, and carcinoma in situ, as well as 65 cases of esophageal epithelium from fetuses at a gestational age of 3-9 mo.

RESULTS

After peptide mass fingerprint analysis and search of protein databases, 21 differential proteins were identified; some of which represent a protein isoform. Varying degrees of expression of PRX6 protein, which was localized mainly in the cytoplasm, were detected in adult and fetal normal esophageal tissues, precancerous lesions, and esophageal cancer. With the progression of esophageal lesions, PRX6 protein expression showed a declining trend (P < 0.05). In fetal epithelium from fetuses at gestational age 3-6 mo, PRX6 protein expression showed a declining trend with age (P < 0.05). PRX6 protein expression was significantly higher in well-differentiated esophageal cancer tissues than in poorly differentiated esophageal cancer tissues (P < 0.05).

CONCLUSION

Development and progression of esophageal cancer result from interactions of genetic changes (accumulation or superposition). PRX6 protein is associated with fetal esophageal development and cancer differentiation.

Tropomyosin-1 acts as a potential tumor suppressor in human oral squamous cell carcinoma

It is widely accepted that oral squamous cell carcinoma (OSCC) is a major contributor to the incidence and mortality of neck and head cancer. Tropomyosin-1 (TPM1), which is expressed at a low level, has been considered a prominent tumor-suppressing gene in a variety of solid tumors, although the precise mechanism of the TPM1 gene in OSCC progression remains unknown. We found that TPM1 expression levels decreased in OSCC patients and OSCC cell lines. The overall and cancer-specific survival of patients who exhibited low TPM1 levels were inferior to those of patients who had high TPM1 levels. It was also found that OSCC patients who suffered from disease stageⅠ-Ⅱ were more likely to have an up-regulated TPM1 expression level, and OSCC patients with lymph node metastasis had a higher probability of exhibiting reduced TPM1 expression. We show that overexpression of TPM1 can promote cell apoptosis and inhibit migration. Our results suggest that TPM1 can suppress tumors in OSCC, and the TPM1 expression level is related to OSCC patient prognosis.

Non-muscle myosin II in disease: mechanisms and therapeutic opportunities

The actin motor protein non-muscle myosin II (NMII) acts as a master regulator of cell morphology, with a role in several essential cellular processes, including cell migration and post-synaptic dendritic spine plasticity in neurons. NMII also generates forces that alter biochemical signaling, by driving changes in interactions between actin-associated proteins that can ultimately regulate gene transcription. In addition to its roles in normal cellular physiology, NMII has recently emerged as a critical regulator of diverse, genetically complex diseases, including neuronal disorders, cancers and vascular disease. In the context of these disorders, NMII regulatory pathways can be directly mutated or indirectly altered by disease-causing mutations. NMII regulatory pathway genes are also increasingly found in disease-associated copy-number variants, particularly in neuronal disorders such as autism and schizophrenia. Furthermore, manipulation of NMII-mediated contractility regulates stem cell pluripotency and differentiation, thus highlighting the key role of NMII-based pharmaceuticals in the clinical success of stem cell therapies. In this Review, we discuss the emerging role of NMII activity and its regulation by kinases and microRNAs in the pathogenesis and prognosis of a diverse range of diseases, including neuronal disorders, cancer and vascular disease. We also address promising clinical applications and limitations of NMII-based inhibitors in the treatment of these diseases and the development of stem-cell-based therapies.

Galectin expression in cancer diagnosis and prognosis: A systematic review

Galectins are a family of proteins that bind to specific glycans thereby deciphering the information captured within the glycome. In the last two decades, several galectin family members have emerged as versatile modulators of tumor progression. This has initiated the development and preclinical assessment of galectin-targeting compounds. With the first compounds now entering clinical trials it is pivotal to gain insight in the diagnostic and prognostic value of galectins in cancer as this will allow a more rational selection of the patients that might benefit most from galectin-targeted therapies. Here, we present a systematic review of galectin expression in human cancer patients. Malignant transformation is frequently associated with altered galectin expression, most notably of galectin-1 and galectin-3. In most cancers, increased galectin-1 expression is associated with poor prognosis while elevated galectin-9 expression is emerging as a marker of favorable disease outcome. The prognostic value of galectin-3 appears to be tumor type dependent and the other galectins require further investigation. Regarding the latter, additional studies using larger patient cohorts are essential to fully unravel the diagnostic and prognostic value of galectin expression. Furthermore, to better compare different findings, consensus should be reached on how to assess galectin expression, not only with regard to localization within the tissue and within cellular compartments but also regarding alternative splicing and genomic variations. Finally, linking galectin expression and function to aberrant glycosylation in cancer cells will improve our understanding of how these versatile proteins can be exploited for diagnostic, prognostic and even therapeutic purposes in cancer patients.

Identification of tumour-related proteins as potential screening markers by proteome analysis-protein profiles of human saliva as a predictive and prognostic tool

The analysis of biomarkers in saliva as a clinical application offers an attractive, simple and rapid diagnostic tool for the short- and long-term monitoring of pathological disorders and drug therapy. The collection of saliva, either in the pure or in its fractionated form, is a relatively easy and non-invasive procedure that is not harmful to the patients and has no complications at all. However, the fluid collection must be clearly defined due to variations in saliva composition, flow rate and day-to-day variability. In order to minimise possible variations, saliva from five patients without squamous cell carcinoma (SCC) pathology and five with suspicion of oral squamous carcinoma (OSCC) were collected and matched at different days and analysed by two-dimensional polyacrylamide gel electrophoresis (2DE-PAGE). Approximately 800 spots were identified, corresponding to 151 different gene products. The list of identified proteins includes a large number of structural proteins like keratins, keratin subunits, enzymes and enzyme inhibitors, cytokines, immunoglobulins as well as amylase and other salivary specific glycoproteins. The majority of proteins that are localised in oral epithelia cells were found as unsolved debris in saliva. One of the identified proteins was significantly overexpressed in OSCC and was selected for further validation by Western blot analysis.

Distinct pattern of chromosomal alterations and pathways in tongue and cheek squamous cell carcinoma

BACKGROUND

The purpose of this study was to investigate the cause of behavioral difference between tongue and cheek squamous cell carcinomas (SCCs) by verifying the copy number alterations (CNAs).

METHODS

Array comparative genomic hybridization (aCGH) was used to profile unique deletions and amplifications that are involved with tongue and cheek SCC, respectively. This was followed by pathway analysis relating to CNA genes from both sites.

RESULTS

The most frequently amplified regions in tongue SCC were 4p16.3, 11q13.4, and 13q34; whereas the most frequently deleted region was 19p12. For cheek SCC, the most frequently amplified region was identified on chromosome 9p24.1-9p23; whereas the most common deleted region was located on chromosome 8p23.1. Further analysis revealed that the most significant unique pathway related to tongue and cheek SCCs was the cytoskeleton remodeling and immune response effect on the macrophage differentiation pathway.

CONCLUSION

This study has showed the different genetic profiles and biological pathways between tongue and cheek SCCs. © 2013 Wiley Periodicals, Inc. Head Neck 36: 1268-1278, 2014.

Short-term exposure of nontumorigenic human bronchial epithelial cells to carcinogenic chromium(VI) compromises their respiratory capacity and alters their bioenergetic signature

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Chromium(VI) impaired respiration and increased glycolytic flux in BEAS-2B cells.

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Cr(VI)-exposed cells shifted to a more fermentative metabolism.

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This metabolic shift was in line with a decreased β-F1-ATPase/GAPDH protein ratio.

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Increased oxidative stress levels suggest impairment of antioxidant defenses.

Previous studies on the impact of hexavalent chromium [Cr(VI)] on mammalian cell energetics revealed alterations suggestive of a shift to a more fermentative metabolism. Aiming at a more defined understanding of the metabolic effects of Cr(VI) and of their molecular basis, we assessed the impact of a mild Cr(VI) exposure on critical bioenergetic parameters (lactate production, oxygen consumption and intracellular ATP levels). Cells derived from normal human bronchial epithelium (BEAS-2B cell line), the main in vivo target of Cr(VI) carcinogenicity, were subjected for 48 h to 1 μM Cr(VI). We could confirm a shift to a more fermentative metabolism, resulting from the simultaneous inhibition of respiration and stimulation of glycolysis. This shift was accompanied by a decrease in the protein levels of the catalytic subunit (subunit β) of the mitochondrial H⁺-ATP synthase (β-F₁-ATPase) and a concomitant marked increase in those of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The corresponding alteration in the β-F₁-ATPase/GAPDH protein ratio (viewed as a bioenergetic signature) upon Cr(VI) exposure was in agreement with the observed attenuation of cellular respiration and enhancement of glycolytic flux. Altogether, these results constitute a novel finding in terms of the molecular mechanisms of Cr(VI) effects.

Immunohistochemical expression of RAGE and its ligand (S100A9) in cervical lesions

Altered expressions of receptor for advanced glycation end-products (RAGE) and its ligand (S100A9) are observed in many cancers and play a key role in inflammation-associated cancer. In our previous study, by two-dimensional gel electrophoresis followed by mass spectrometry, the expression of S100A9 protein was found to increase in squamous cervical cancer compared with adjacent normal cervical tissues. Therefore, in the present study we observed the expressions of S100A9 and RAGE in 30 chronic cervicitis, 50 cervical intraepithelial neoplasia (CIN), and 40 squamous cervical cancer (SCC) using immunohistochemical analysis and analyzed the differential expression and possible role of S100A9 and RAGE in cancer development. Immunohistochemical findings were as follows: the expressions of S100A9 and RAGE were demonstrated in chronic cervicitis, CIN, and SCC. Moreover, their expressions were gradually increasing as the tumor progressed. In SCC, the staining scores of S100A9 and RAGE were significantly higher in well-differentiated tumors compared to moderately and poorly differentiated tumors. The expression of S100A9 in epithelial cells exhibited a positive correlation to RAGE expression in chronic cervicitis, CIN, and SCC. There were no significant difference of S100A9 immunoreactivity in stromal cells among chronic cervicitis, CIN, and SCC. Moreover, there was no correlation between S100A9 immunoreactivity in stromal cells of SCC and clinicopathological parameters. Finally, double immunohistochemistry illustrated that RAGE and S100A9 co-express in SCC. In conclusion, RAGE binds its ligand (S100A9), which plays an important role in the development of SCC. In addition, the expressions of S100A9 and RAGE in SCC tumor cells were closely associated with histological differentiation.

HspB1, HspB5 and HspB4 in Human Cancers: Potent Oncogenic Role of Some of Their Client Proteins

Human small heat shock proteins are molecular chaperones that regulate fundamental cellular processes in normal unstressed cells as well as in many cancer cells where they are over-expressed. These proteins are characterized by cell physiology dependent changes in their oligomerization and phosphorylation status. These structural changes allow them to interact with many different client proteins that subsequently display modified activity and/or half-life. Nowdays, the protein interactomes of small Hsps are under intense investigations and will represent, when completed, key parameters to elaborate therapeutic strategies aimed at modulating the functions of these chaperones. Here, we have analyzed the potential pro-cancerous roles of several client proteins that have been described so far to interact with HspB1 (Hsp27) and its close members HspB5 (αB-crystallin) and HspB4 (αA-crystallin).

Laser ionization mass spectrometry in oral squamous cell carcinoma

Biomarker research in oral squamous cell carcinoma (OSCC) aims for screening/early diagnosis and in predicting its recurrence, metastasis and overall prognosis. This article reviews the current molecular perspectives and diagnosis of oral cancer with proteomics using matrix-assisted laser desorption ionization (MALDI) and surface-enhanced laser desorption ionization (SELDI) mass spectrometry (MS). This method shows higher sensitivity, accuracy, reproducibility and ability to handle complex tissues and biological fluid samples. However, the data interpretation tools of contemporary mass spectrometry still warrant further improvement. Based on the data available with laser-based mass spectrometry, biomarkers of OSCC are classified as (i) diagnosis and prognosis, (ii) secretory, (iii) recurrence and metastasis, and (iv) drug targets. Majority of these biomarkers are involved in cell homeostasis and are either physiologic responders or enzymes. Therefore, proteins directly related to tumorigenesis have more diagnostic value. Salivary secretory markers are another group that offers a favourable and easy strategy for non-invasive screening and early diagnosis in oral cancer. Key molecular inter-related pathways in oral carcinogenesis are also intensely researched with software analysis to facilitate targeted drug therapeutics. The review suggested the need for incorporating 'multiple MS or tandem approaches' and focusing on a 'group of biomarkers' instead of single protein entities, for making early diagnosis and treatment for oral cancer a reality.

Promoter hypermethylation of the gene encoding heat shock protein B1 in oral squamous carcinoma cells

OBJECTIVE

The mechanism responsible for the regulation of HSPB1 expression in oral squamous cell carcinoma was explored in this study.

STUDY DESIGN

The expression and the methylation status of HSPB1 in oral squamous carcinoma cells were examined using real-time reverse transcription-PCR, methylation-specific PCR and pyrosequencing.

RESULTS

HSPB1 expression was weakly expressed in oral squamous carcinoma cell lines (N = 4) as compared to that of normal human oral keratinocytes. The lower expressed HSPB1 was associated with promoter hypermethylation of the HSPB1 gene, and the expression of HSPB1 could be induced by treating the cells with a DNA methyltransferase inhibitor, RG108. Promoter hypermethylation of the HSPB1 gene was also noted in primary oral squamous carcinomas, concomitant with reduced levels of HSPB1 gene expression, as compared to those of the paired neighboring normal tissues.

CONCLUSION

Aberrant promoter hypermethylation of the HSPB1 gene may explain the reduced expression of HSPB1 noted in oral cancer cells.

Proteomic profile of keratins in cancer of the gingivo buccal complex: consolidating insights for clinical applications

Keratins play a major role in several cellular functions. Each tissue type expresses a specific set of keratins. The immense potential of keratins as diagnostic and prognostic markers for different cancers is emerging. Oral cancer is the fifteenth most common cancer worldwide. However, comprehensive information on the profile of keratins in the oral cavity is not available. Several independent reports have identified keratins using antibody based techniques which have pitfalls due to the cross reactivity of the antibodies to this set of very homologous proteins. A few recent proteomic studies have reported the identification of keratins in head and neck cancer. Majority of the studies have used tissues from the head and neck region without specifying subsites. This study reports the analysis of enriched preparations of keratins from cancer of the gingivo buccal complex (GBC) using MS, 2DE, WB, silver staining of 2DE gels and IHC. Our study reveals the absence of K4 and K13 and presence of K14, K16, and K17, in cancers of the GBC and combination of these expression patterns in the cut margins. This report also shows that K13 is glycosylated. This well characterized profile of keratins may have potential to be used in clinics.

BIOLOGICAL SIGNIFICANCE

In recent years the immense potential of keratins as diagnostic and prognostic markers for different cancers is emerging. However, comprehensive information on the profile of keratins in the oral cavity is not available. Several independent reports have identified keratins using only antibody based techniques which have pitfalls due to the cross reactivity of the antibodies to this set of very homologous proteins. This study reports the analysis of enriched preparations of keratins from a subsite of the oral cavity, the gingivo buccal complex (GBC) using mass spectrometry, 2DE, western blotting, silver staining of 2DE gels and IHC. The proteomic analysis shows the absence of K4 and K13 and presence of K14, K16, and K17 in cancers of the GBC and combination of these expression patterns in the cut margins. This well characterized profile of keratins from the gingivo buccal complex provides defined markers which may have potential to be used in the clinics.

Calreticulin expression in infiltrating ductal breast carcinomas: relationships with disease progression and humoral immune responses

The aim of this study was to evaluate calreticulin expression in infiltrating ductal breast carcinomas (IDCAs), as well as its relationships with clinicopathological parameters of the disease. Using a two-dimensional gel electrophoresis/matrix-assisted laser desorption ionization time of flight mass spectrometry investigation coupled to an immunohistochemical approach, we have assessed the expression of calreticulin in IDCAs, as well as in other types of breast tumors. The humoral immune response against calreticulin was estimated using a serological proteomics-based strategy. Proteomic analyses revealed an increased expression of calreticulin in IDCA tumors. Using immunohistochemistry, overexpression of calreticulin was confirmed in 51 additional tumor specimens. Statistical analyses revealed, however, no significant correlations between calreticulin expression and clinicopathological parameters of the disease including tumor stage, patient age, SBR grade, and lymph node metastasis occurrence. A significant association was found, however, with estrogen receptor status. This study demonstrates the upregulation of calreticulin in IDCA tissues which may highlight its involvement in breast cancer development. Our findings also support a link between calreticulin expression and estrogen transduction pathways. Our results do not, however, support the involvement of calreticulin in the development of a humoral immune response in IDCAs.

Expression of the molecular chaperone αB-crystallin in infiltrating ductal breast carcinomas and the significance thereof: an immunohistochemical and proteomics-based strategy

This study aims to evaluate αB-crystallin expression in infiltrating ductal breast carcinomas (IDCAs), as well as, its prognostic significance. Using a two-dimensional electrophoresis matrix-assisted laser desorption/ionisation-time of flight mass spectrometry investigation coupled to an immunohistochemical approach, we have assessed the expression of αB-crystallin in IDCAs, as well as, in other types of breast tumors (invasive lobular carcinomas, medullary carcinomas, and in situ ductal carcinomas). Correlation between αB-crystallin expression and clinicopathological parameters of breast cancer has also been investigated. Proteomic analyses revealed an increased expression of αB-crystallin in IDCA tumors compared to adjacent nontumor tissues. Overexpression of this molecular chaperone was further confirmed in 51 tumor specimens. Statistical analyses revealed, however, no significant correlations between αB-crystallin expression and clinicopathological parameters of the disease (tumor stage, patient age, hormone receptors, SBR grade, and lymph node metastases). This study demonstrates the upregulation of αB-crystallin in IDCA tissues which may highlight its possible involvement in breast cancer development. Our findings do not, however, support the involvement of this molecular chaperone in the progression of this disease.

Alterations in the immunoexpression of galectins-1, -3 and -7 between different grades of oral epithelial dysplasia

INTRODUCTION

Oral epithelial dysplasia (OED) is a potentially malignant lesion characterized by a combination of cytological and architectural anomalies, which are essential for its diagnosis. Galectins are proteins that participate in cell cycle, adhesion and differentiation, apoptosis, and immune responses, as well as in cancer development and progression.

MATERIALS AND METHODS

The aim of this study was to analyze the immunohistochemical expression of galectins-1, -3, and -7 in the OED (21 low risk and 29 high risk) and normal oral mucosa (NOM). The binary grading system was used.

RESULTS

Galectin-1 was expressed in the middle/lower third in most OED cases. Nuclear/cytoplasmic staining was observed in most low-risk and high-risk OEDs. All cases of NOM were negative for galectin-1. Galectin-3 was expressed in the middle/lower third in most low-risk cases. Nuclear/cytoplasmic staining was noted in most low-risk and high-risk OEDs. Middle/lower third and in membrane staining was detected in four cases of NOM for galectin-3. Galectin-7 was expressed in the upper/middle third in most of OED cases. Nuclear/cytoplasmic staining predominated in low-risk and high-risk OEDs. Galectin-7 was detected in four cases of NOM, all of them presenting staining in the upper/middle third and in the membrane.

CONCLUSION

The differences in the immunoexpression of galactin-1, -3, and -7 between different grades of OEDs suggest the involvement of this protein in the progression of dysplasias.

From the salivary proteome to the OralOme: comprehensive molecular oral biology

OBJECTIVES

There have been several efforts to identify the protein components of saliva. Some of these studies were conducted in healthy individuals and other in individuals with different oral and systemic disorders. However, a resource compiling and reviewing all of the proteins identified in proteomic studies is still lacking. The aim of this project is to develop such a resource.

DESIGN

The proteins identified by proteomic studies were compiled and all information concerning them was manually curated according to "IPI History search" and UniProt. Proteins were classified according to gene ontology using PANTHER. The involvement of each protein in disease was scrutinized using DAVID and a classification into protein disease classes was performed.

RESULTS

This survey of proteins in the oral cavity lead to the identification of 3397 non-redundant proteins, 605 altered in pathological conditions and 51 present only in disease. These proteins originate from different sources: 3115 from saliva, 990 from oral mucosa and 1929 from plasma. All protein sources contribute with different numbers and types of proteins to identical functions. However, each source produces specific proteins. Examples of the use of this proteomics database of saliva included the analysis of the changes in the proteome associated with periodontitis and a survey of systemic disease potential biomarkers in saliva.

CONCLUSION

The database generated with this work and the information therein stands as a resource for investigators/clinicians studying the oral biology, searching for molecular disease markers, developing diagnostic and prognostic tests, and contributing to the discovery of new therapeutic agents.

Proteomic analysis of anti-tumor effects of 11-dehydrosinulariolide on CAL-27 cells

The anti-tumor effects of 11-dehydrosinulariolide, an active ingredient isolated from soft coral Sinularia leptoclados, on CAL-27 cells were investigated in this study. In the MTT assay for cell proliferation, increasing concentrations of 11-dehydrosinulariolide decreased CAL-27 cell viability. When a concentration of 1.5 μg/mL of 11-dehydrosinulariolide was applied, the CAL-27 cells viability was reduced to a level of 70% of the control sample. The wound healing function decreased as the concentration of 11-dehydrosinulariolide increased. The results in this study indicated that treatment with 11-dehydrosinulariolide for 6 h significantly induced both early and late apoptosis of CAL-27 cells, observed by flow cytometric measurement and microscopic fluorescent observation. A comparative proteomic analysis was conducted to investigate the effects of 11-dehydrosinulariolide on CAL-27 cells at the molecular level by comparison between the protein profiling (revealed on a 2-DE map) of CAL-27 cells treated with 11-dehydrosinulariolide and that of CAL-27 cells without the treatment. A total of 28 differential proteins (12 up-regulated and 16 down-regulated) in CAL-27 cells treated with 11-dehydrosinulariolide have been identified by LC-MS/MS analysis. Some of the differential proteins are associated with cell proliferation, apoptosis, protein synthesis, protein folding, and energy metabolism. The results of this study provided clues for the investigation of biochemical mechanisms of the anti-tumor effects of 11-dehydrosinulariolide on CAL-27 cells and could be valuable information for drug development and progression monitoring of oral squamous cell carcinoma (OSCC).

Identification of proteins secreted by head and neck cancer cell lines using LC-MS/MS: Strategy for discovery of candidate serological biomarkers

In search of blood-based biomarkers that would enhance the ability to diagnose head and neck/oral squamous cell carcinoma (HNOSCC) in early stages or predict its prognosis, we analyzed the HNOSCC secretome (ensemble of proteins secreted and/or shed from the tumor cells) for potential biomarkers using proteomic technologies. LC-MS/MS was used to identify proteins in the conditioned media of four HNOSCC cell lines (SCC4, HSC2, SCC38, and AMOSIII); 140 unique proteins were identified on the basis of 5% global false discovery rate, 122 of which were secretory proteins, with 29 being previously reported to be overexpressed in HNOSCC in comparison to normal head and neck tissues. Of these, five proteins including α-enolase, peptidyl prolyl isomerase A/cyclophilin A, 14-3-3 ζ, heterogeneous ribonucleoprotein K, and 14-3-3 σ were detected in the sera of HNOSCC patients by Western blot analysis. Our study provides the evidence that analysis of head and neck cancer cells' secretome is a viable strategy for identifying candidate serological biomarkers for HNOSCC. In future, these biomarkers may be useful in predicting the likelihood of transformation of oral pre-malignant lesions, prognosis of HNOSCC patients and evaluate response to therapy using minimally invasive tests.

Database and interaction network of genes involved in oral cancer: Version II

The oral cancer gene database has been compiled to enable fast retrieval of updated information and role of the genes implicated in oral cancer. The first version of the database with 242 genes was published in Online Journal of Bioinformatics 8(1), 41-44, 2007. In the second version, the database has been enlarged to include 374 genes by adding 132 gene entries. The architecture and format of the database is similar to the earlier version, and includes updated information and external hyperlinks for all the genes. The functional gene interaction network for important biological processes and molecular functions has been rebuilt based on 374 genes using 'String 8.3'. The database is freely available at http://www.actrec.gov.in/OCDB/index.htm and provides the scientist information and external links for the genes involved in oral cancer, interactions between them, and their role in the biology of oral cancer along with clinical relevance.

The bioenergetic signature of isogenic colon cancer cells predicts the cell death response to treatment with 3-bromopyruvate, iodoacetate or 5-fluorouracil

Background

Metabolic reprogramming resulting in enhanced glycolysis is a phenotypic trait of cancer cells, which is imposed by the tumor microenvironment and is linked to the down-regulation of the catalytic subunit of the mitochondrial H⁺-ATPase (β-F1-ATPase). The bioenergetic signature is a protein ratio (β-F1-ATPase/GAPDH), which provides an estimate of glucose metabolism in tumors and serves as a prognostic indicator for cancer patients. Targeting energetic metabolism could be a viable alternative to conventional anticancer chemotherapies. Herein, we document that the bioenergetic signature of isogenic colon cancer cells provides a gauge to predict the cell-death response to the metabolic inhibitors, 3-bromopyruvate (3BrP) and iodoacetate (IA), and the anti-metabolite, 5-fluorouracil (5-FU).

Methods

The bioenergetic signature of the cells was determined by western blotting. Aerobic glycolysis was determined from lactate production rates. The cell death was analyzed by fluorescence microscopy and flow cytometry. Cellular ATP concentrations were determined using bioluminiscence. Pearson's correlation coefficient was applied to assess the relationship between the bioenergetic signature and the cell death response. In vivo tumor regression activities of the compounds were assessed using a xenograft mouse model injected with the highly glycolytic HCT116 colocarcinoma cells.

Results

We demonstrate that the bioenergetic signature of isogenic HCT116 cancer cells inversely correlates with the potential to execute necrosis in response to 3BrP or IA treatment. Conversely, the bioenergetic signature directly correlates with the potential to execute apoptosis in response to 5-FU treatment in the same cells. However, despite the large differences observed in the in vitro cell-death responses associated with 3BrP, IA and 5-FU, the in vivo tumor regression activities of these agents were comparable.

Conclusions

Overall, we suggest that the determination of the bioenergetic signature of colon carcinomas could provide a tool for predicting the therapeutic response to various chemotherapeutic strategies aimed at combating tumor progression.

Analysis of differentially expressed proteins in oral squamous cell carcinoma by MALDI-TOF MS

PURPOSE

To explore the presence of differentially expressed proteins in OSCC for discrimination of tumour and normal mucosa to establish potential biomarkers and therapeutic targets.

EXPERIMENTAL DESIGN

Paired protein samples of 12 individuals (tongue cancer and non-cancerous mucosa) were separated by two-dimensional polyacrylamid gel electrophoresis. The protein patterns were compared pairwise and protein spots were quantified. We identified about 70 regulated proteins which we subsequently identified by MALDI-TOF mass spectrometry.

RESULTS

Cancerous and non-cancerous tissues could be most precisely distinguished by a panel of proteins. They include the heat shock proteins (hsp)70 and 90, keratins (ck) 5, 6, 13, 14, 16, 17 and 19, beta globin, alpha-2-actin, stratifin, tropomyosin, calreticulin precursor, beta-2-tubulin, galectin7, thioredoxin, involucrin, adenylyl-cyclase-associated protein, disulfide isomerase-associated protein, thyrosine 3-monooxygenase, MYL2 and the s100 calcium binding protein. MYL3, cardiac muscle alpha actin 1 proprotein and transferrin were under-represented in OSCC. Six biomarkers, ck6 und ck13, beta globin, alpha-2-actin, hsp70 and hsp90 discriminated best between cancerous and non-cancerous oral tissues. All over-expressed proteins were analysed by STRING-analysis to highlight experimentally determined and computationally predicted interactions between the proteins. Especially involucrin, hsp70, calreticulin precursor, stratifin, (ck) 5, 6, 14, 19, tyrosine 3-monooxygenase, beta-2-tubulin and disulfide isomerase associated protein showed multiple relations.

CONCLUSION

We identified six proteins which are differentially expressed in most OSCC compared to healthy tissues. Of those, by string analysis, multiple interaction partners are assumed for hsp70. This protein is supposed to be the most promising candidate as marker molecule and target for OSCC therapy.

Silencing heat shock protein 27 decreases metastatic behavior of human head and neck squamous cell cancer cells in vitro

The small heat shock protein 27 (Hsp27) is a molecular chaperone that is involved in a variety of cellular functions in cancer cells. The purpose of this research is to study Hsp27 in vitro metastatic behaviors of head and neck squamous cell carcinoma cells (HNSCC). The expression of Hsp27 in primary and metastatic cell lines derived from the primary HNSCC and a synchronous lymph node metastasis in the same patient was determined using real-time PCR and Western blotting. Proliferation of the primary and metastatic HNSCC cell lines was evaluated using the MTS proliferation assay. Metastatic behavior was assessed using migration and invasion assays. SiRNA knockdown of Hsp27 was performed in the highly migratory metastatic HNSCC cell line. MTS assays showed that the primary (UM-SCC-22A) and metastatic (UM-SCC-22B) HNSCC have similar proliferation rates. However, UM-SCC-22B derived from the metastasis showed 2.3- to 3.6-fold higher migration ability and 2-fold higher invasion ability than UM-SCC-22A. Real-time PCR demonstrated that Hsp27 mRNA is 22.4-fold higher in metastatic UM-SCC-22B than primary UM-SCC-22A. Similarly, Western blotting showed that Hsp27 is rarely detectable in UM-SCC-22A whereas UM-SCC-22B expresses a 25-fold higher level of Hsp27 protein. SiRNA-mediated knockdown of Hsp27 in UM-SCC-22B reduced Hsp27 mRNA expression by nearly 6-fold and protein expression by 23-fold. Furthermore, siRNA knockdown of Hsp27 decreased metastatic behaviors of UM-SCC-22B by 3- to 4-fold in migration and 2-fold in cell invasion reducing cell invasion and migration to levels similar to the primary HNSCC UM-SCC-22A. These data indicate that Hsp27 may regulate metastatic potential of HNSCC cancer cells. Targeting Hsp27 may decrease metastasis in head and neck squamous cell cancer cells.

Mass spectrometry-based clinical proteomics: head-and-neck cancer biomarkers and drug-targets discovery

Mass spectrometry (MS)-based proteomics is a rapidly developing technology for both qualitative and quantitative analyses of proteins, and investigations into protein posttranslational modifications, subcellular localization, and interactions. Recent advancements in MS have made tremendous impact on the throughput and comprehensiveness of cancer proteomics, paving the way to unraveling deregulated cellular pathway networks in human malignancies. In turn, this knowledge is rapidly being translated into the discovery of novel potential cancer markers (PCMs) and targets for molecular therapeutics. Head-and-neck cancer is one of the most morbid human malignancies with an overall poor prognosis and severely compromised quality of life. Early detection and novel therapeutic strategies are urgently needed for more effective disease management. The characterizations of protein profiles of head-and-neck cancers and non-malignant tissues, with unprecedented sensitivity and precision, are providing technology platforms for identification of novel PCMs and drug targets. Importantly, low-abundance proteins are being identified and characterized, not only from the tumor tissues, but also from bodily fluids (plasma, saliva, and urine) in a high-throughput and unbiased manner. This review is a critical appraisal of recent advances in MS-based proteomic technologies and platforms for facilitating the discovery of biomarkers and novel drug targets in head-and-neck cancer. A major challenge in the discovery and verification of these cancer biomarkers is the typically limited availability of well-characterized and adequately stored clinical samples in tumor and sera banks, collected using recommended procedures, and with detailed information on clinical, pathological parameters, and follow-up. Most biomarker discovery studies use limited number of clinical samples and verification of cancer markers in large number of samples is beyond the scope of a single laboratory. The validation of these potential markers in large sample cohorts in multicentric studies is needed for their translation from the bench to the bedside.

Post-transcriptional regulation of the mitochondrial H(+)-ATP synthase: a key regulator of the metabolic phenotype in cancer

A distinctive metabolic trait of tumors is their enforced aerobic glycolysis. This phenotype was first reported by Otto Warburg, who suggested that the increased glucose consumption of cancer cells under aerobic conditions might result from an impaired bioenergetic activity of their mitochondria. A central player in defining the bioenergetic activity of the cell is the mitochondrial H(+)-ATP synthase. The expression of its catalytic subunit β-F1-ATPase is tightly regulated at post-transcriptional levels during mammalian development and in the cell cycle. Moreover, the down-regulation of β-F1-ATPase is a hallmark of most human carcinomas. In this review we summarize our present understanding of the molecular mechanisms that participate in promoting the "abnormal" aerobic glycolysis of prevalent human carcinomas. The role of the ATPase Inhibitor Factor 1 (IF1) and of Ras-GAP SH3 binding protein 1 (G3BP1), controlling the activity of the H(+)-ATP synthase and the translation of β-F1-ATPase mRNA respectively in cancer cells is emphasized. Furthermore, we underline the role of mitochondrial dysfunction as a pivotal player of tumorigenesis.

Peroxiredoxin 2: a potential biomarker for early diagnosis of hepatitis B virus related liver fibrosis identified by proteomic analysis of the plasma

Background

Liver fibrosis is a middle stage in the course of chronic Hepatitis B virus (HBV) infection, which will develop into cirrhosis and eventually hepatocellular carcinoma (HCC) if not treated at the early stage. Considering the limitations and patients' reluctance to undergo liver biopsy, a reliable, noninvasive diagnostic system to predict and assess treatment and prognosis of liver fibrosis is needed. The aim of this study was to identify biomarkers for early diagnosis of HBV related liver fibrosis.

Method

Plasma samples from 7 healthy volunteers and 27 HBV infected patients with different stages of fibrosis were selected for 2-DIGE proteomic screening. One-way ANOVA analysis was used to assess differences in protein expression among all groups. The alteration was further confirmed by western blotting. Plasma levels of 25 serological variables in 42 healthy volunteers and 68 patients were measured to establish a decision tree for the detection of various stages fibrosis.

Result

The up-regulated proteins along with fibrosis progress included fibrinogen, collagen, macroglobulin, hemopexin, antitrypsin, prealbumin and thioredoxin peroxidase. The down-regulated proteins included haptoglobin, serotransferrin, CD5 antigen like protein, clusterin, apolipoprotein and leucine-rich alpha-2-glycoprotein. For the discrimination of milder stage fibrosis, the area under curve for Prx II was the highest. Four variables (PT, Pre, HA and Prx II) were selected from the 25 variables to construct the decision tree. In a training group, the correct prediction percentage for normal control, milder fibrosis, significant fibrosis and early cirrhosis was 100%, 88.9%, 95.2% and 100%, respectively, with an overall correct percent of 95.9%.

Conclusion

This study showed that 2-D DIGE-based proteomic analysis of the plasma was helpful in screening for new plasma biomarkers for liver disease. The significant up-expression of Prx II could be used in the early diagnosis of HBV related liver fibrosis.

Identification of esophageal carcinoma-associated proteins by proteomics in Han, Uygur and Kazakh patients with esophageal carcinoma in Xinjiang, China

AIM: To conduct a serum protein profile analysis in Han, Uygur and Kazakh patients with esophageal carcinoma (EC) in Xinjiang, China.

METHODS: Serum samples from patients with EC (43 Han, 43 Uygur and 41 Kazakh subjects) were detected by weak cation exchange (CM10) protein chip assay using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technology to screen differentially expressed serum markers for EC.

RESULTS: The peaks at the mass to charge ratios (M/Z) 4 310.0109, 8 713.0142 and 7 993.0223 were significantly different between Han and Uygur EC patients (P < 0.05). The peaks at M/Z 4 310.0184, 8 167.9277, 8 158.1117, 13 789.4864, 8 067.7056, 4 611.9098, 7 993.4422 and 16 146.8706 were significantly different between Han and Kazakh EC patients (P < 0.05). The peaks at M/Z 9 161.7944, 4 611.6342, 6 649.6163 and 4 979.3807 were significantly different between Uygur and Kazakh EC patients (P < 0.05). The peat at M/Z 4 310.0109 was highly expressed in Uygur and Kazakh patients but lowly expressed in Han patients.

CONCLUSION: The protein fingerprints are significantly different among Han, Uygur and Kazakh EC patients in Xinjiang, China, which can be used to build a diagnostic model of EC.

Selective inhibition of β-F1-ATPase mRNA translation in human tumours

Down-regulation of β-F1-ATPase (the catalytic subunit of the mitochondrial H+-ATP synthase) is a hallmark of many human tumours. The expression level of β-F1-ATPase provides a marker of the prognosis of cancer patients, as well as of the tumour response to chemotherapy. However, the mechanisms that participate in down-regulating its expression in human tumours remain unknown. In the present study, we have investigated the expression of β-F1-ATPase mRNA (termed β-mRNA) in breast, colon and lung adenocarcinomas and squamous carcinomas of the lung. Despite the down-regulation of the protein, tumour β-mRNA levels remained either unchanged (breast and lung adenocarcinomas) or significantly increased (colon and squamous lung carcinomas) when compared with paired normal tissues, suggesting a specific translation-masking event for β-mRNA in human cancer. Consistently, we show using cell-free translation assays that a large fraction (~70%) of protein extracts derived from breast and lung adenocarcinomas specifically repress the translation of β-mRNA. We show that the 3′UTR (3′ untranslated region) of human β-mRNA is a relevant cis-acting element required for efficient translation of the transcript. However, an RNA chimaera bearing the 3′UTR of human β-mRNA does not recapitulate the inhibitory effect of tumour extracts on β-mRNA translation. Overall, the findings of the present study support the hypothesis that down-regulation of the bioenergetic activity of mitochondria in human tumours is exerted by translation silencing of β-mRNA.

Overexpression of Galectin-1 is negatively correlated with pathologic differentiation grade in oral squamous cell carcinoma

PURPOSE

To determine the Galectin-1 protein expression in oral squamous cell carcinoma (OSCC).

METHODS

Comparative proteomic analysis of an in vitro cellular carcinogenesis model of OSCC we previously established was performed to identify differentially expressed proteins. Galectin-1 was further validated in vitro (human immortalized oral epithelia cell line and OSCC lines) and in vivo (tissue samples from OSCC patients) by Western blotting and immunohistochemistry, respectively.

RESULTS

Increased Galectin-1 protein expression was identified in the cancerous cell line compared with the immortalized oral epithelial cell line in the in vitro cellular carcinogenesis model, and then validated in the OSCC lines and cancerous tissues. Galectin-1 protein expression was negatively correlated with the tumor pathologic differentiation grades, a higher Galectin-1 protein expression indicating a poorer pathologic differentiation grade.

CONCLUSIONS

Galectin-1 protein expression level increases in OSCC, it may serve as a candidate marker for pathologic differentiation grade of OSCC.

Advances and Perspectives in the Molecular Diagnosis of Head and Neck Cancer

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is a debilitating and lethal disease. Despite significant advances in radiotherapy and surgical management, the 5-year survival rate for head and neck cancer has remained a dismal 50%. Advances in early detection have been made, but to improve patient outcomes better biomarkers and targeted therapeutic agents are needed. Novel biomarkers can improve early detection and provide data to optimize therapeutic strategy and patient survival, and could lead to potentially effective targeted therapies. OBJECTIVE: Report the advances in the discovery of novel biomarkers for HNSCC, and review the potential utility of biomarkers in the molecular diagnosis of HNSCC. METHODS: A review of the English literature (PubMed) from 1980 to 2009. RESULTS/CONCLUSION: Currently the most widely accepted biomarker for HNSCC is high risk HPV status. EGFR is another promising biomarker, however, further research is necessary to determine its prognostic benefit. A large number of promising biomarker candidates are currently being evaluated including epigenetic, expression, and genomic based markers. Studies to validate the sensitivity and specificity of these biomarkers in clinical samples from adequately powered prospective cohorts are needed for successful translation of these findings into potential molecular diagnostic, prognostic, and therapeutic biomarkers for HNSCC.