Differential tissue-specific protein markers of vaginal carcinoma

Implications and progression of peroxiredoxin 2 (PRDX2) in various human diseases

Peroxiredoxin 2 (PRDX2), a characteristic 2-Cys enzyme is one of the foremost effective scavenger proteins against reactive oxygen species (ROS) and hydrogen peroxide (H2O2) defending cells against oxidative stress. Dysregulation of this antioxidant raises the quantity of ROS and oxidative stress implicated in several diseases. PRDX2 lowers the generation of ROS that takes part in controlling several signalling pathways occurring in neurons, protecting them from stress caused by oxidation and an inflammatory harm. Depending on the aetiological variables, the kind of cancer, and the stage of tumour development, PRDX2 may behave either as an onco-suppressor or a promoter. However, overexpression of PRDX2 may be linked to the development of numerous cancers, including those of the colon, cervix, breast, and prostate. PRDX2 also plays a beneficial effect in inflammatory diseases. PRDX2 being a thiol-specific peroxidase, is known to control proinflammatory reactions. The spilling of PRDX2, on the other hand, accelerates cognitive impairment following a stroke by triggering an inflammatory reflex. PRDX2 expression patterns in vascular cells tend to be crucial to its involvement in cardiovascular diseases. In vascular smooth muscle cells, if the protein tyrosine phosphatase is restricted, PRDX2 could avoid the neointimal thickening which relies on platelet derived growth factor (PDGF), a vital component of vascular remodelling. A proper PRDX2 balance is therefore crucial. The imbalance causes a number of illnesses, including cancers, inflammatory diseases, cardiovascular ailments, and neurological and neurodegenerative problems which are discussed in this review.

MiR-92a-2-5p suppresses esophageal squamous cell carcinoma cell proliferation and invasion by targeting PRDX2

MicroRNAs (miRNAs) can function as negative regulators of gene expression by binding to the 3'-untranslated region (3'-UTR) of target genes. The aberrant expression of miRNAs in neoplasm is extensively associated with tumorigenesis and cancer progression, including esophageal squamous cell carcinoma (ESCC). Our previous investigation has identified the oncogenic roles of Peroxiredoxin2 (PRDX2) in ESCC progression; however, its upstream regulatory mechanism remains to be elucidated. By merging the prediction results from miRWalk2.0 and miRNA differential expression analysis results based on The Cancer Genome Atlas Esophageal Carcinoma (TCGA-ESCA) database, eight miRNA candidates were predicted to be the potential regulatory miRNAs of PRDX2, followed by further identification of miR-92a-2-5p as the putative miRNA of PRDX2. Subsequent functional studies demonstrated that miR-92a-2-5p can suppress ESCC cell proliferation and migration, as well as tumor growth in subcutaneous tumor xenograft models, which might be mediated by the suppression of AKT/mTOR and Wnt3a/β-catenin signaling pathways upon miR-92a-2-5p mimic transfection condition. These data revealed the tumor suppressive functions of miR-92a-2-5p in ESCC by targeting PRDX2.

As a potential predictor of pan-cancer, UBE2S is related to tumor-associated macrophage infiltration

Background: At the pan-cancer level, exploring the expression and prognostic significance of a gene, such as UBE2S, will help to gain insight into the role of the gene and its feasibility for cancer screening, prognosis assessment and even gene therapy. Methods: The Cancer Genome Atlas, Human Protein Atlas, Kaplan-Meier, Tumor Immunology Estimation Resource and other databases were used to analyze the expression of UBE2S at the pan-cancer level, its prognosis and the role of the immune microenvironment. Immunohistochemistry samples of tumor tissue collected in our clinic were taken as verification. Results: UBE2S is significantly overexpressed in pan-cancer and is closely associated with malignant clinical features, poor prognosis and tumor-associated macrophages. Conclusion: UBE2S may be a potential diagnostic and prognostic marker for pan-cancer and is associated with tumor-associated macrophages.

Metabolic Functions of Biliverdin IXβ Reductase in Redox-Regulated Hematopoietic Cell Fate

Cytoprotective heme oxygenases derivatize heme to generate carbon monoxide, ferrous iron, and isomeric biliverdins, followed by rapid NAD(P)H-dependent biliverdin reduction to the antioxidant bilirubin. Recent studies have implicated biliverdin IXβ reductase (BLVRB) in a redox-regulated mechanism of hematopoietic lineage fate restricted to megakaryocyte and erythroid development, a function distinct and non-overlapping from the BLVRA (biliverdin IXα reductase) homologue. In this review, we focus on recent progress in BLVRB biochemistry and genetics, highlighting human, murine, and cell-based studies that position BLVRB-regulated redox function (or ROS accumulation) as a developmentally tuned trigger that governs megakaryocyte/erythroid lineage fate arising from hematopoietic stem cells. BLVRB crystallographic and thermodynamic studies have elucidated critical determinants of substrate utilization, redox coupling and cytoprotection, and have established that inhibitors and substrates bind within the single-Rossmann fold. These advances provide unique opportunities for the development of BLVRB-selective redox inhibitors as novel cellular targets that retain potential for therapeutic applicability in hematopoietic (and other) disorders.

Calreticulin nuclear translocalization alleviates CaM/CaMKII/CREB signaling pathway to enhance chemosensitivity in HDAC inhibitor-resistant hepatocellular carcinoma cells

Calreticulin (CRT) is located in the endoplasmic reticulum (ER), it helps proteins fold correctly inside the ER, and acts as a modulator of Ca²⁺ homeostasis. Aberrant expression of CRT is implicated in several cancer types, qualifying CRT as a potential therapeutic target. However, it remains unclear how CRT affects specific oncogenic pathways. In this study, we used histone deacetylase inhibitors (HDACis) to establish drug-resistant liver cancer cells and further analyzed the molecular mechanism of development of drug resistance in those cells. The 2D gel electrophoresis and RT-PCR data showed that CRT was downregulated in HDACis-resistant cells by comparing with HA22T parental cells. We previously elucidated the development of drug-resistance in HCC cells via activation of PP1-eIF2α pathway, but not via ER stress pathway. Here, we show that thapsigargin induced ER stress through mechanism other than ER stress downstream protein GRP78-PERK to regulate CRT expression in HDACis-R cells. Moreover, the expression level of CRT was not the main cause of apoptosis in HDACis-resistant cells. Mechanistic studies identified the apoptosis factors in the nucleus-the HDACis-mediated overexpression of CRT, CRT translocation to the cell nucleus, and reduced CaM/CaMKII/CREB pathway-that led to chemosensitivity in HDACis-R HCC cells.

Self-Assembled Peptide Habitats to Model Tumor Metastasis

Metastatic tumours are complex ecosystems; a community of multiple cell types, including cancerous cells, fibroblasts, and immune cells that exist within a supportive and specific microenvironment. The interplay of these cells, together with tissue specific chemical, structural and temporal signals within a three-dimensional (3D) habitat, direct tumour cell behavior, a subtlety that can be easily lost in 2D tissue culture. Here, we investigate a significantly improved tool, consisting of a novel matrix of functionally programmed peptide sequences, self-assembled into a scaffold to enable the growth and the migration of multicellular lung tumour spheroids, as proof-of-concept. This 3D functional model aims to mimic the biological, chemical, and contextual cues of an in vivo tumor more closely than a typically used, unstructured hydrogel, allowing spatial and temporal activity modelling. This approach shows promise as a cancer model, enhancing current understandings of how tumours progress and spread over time within their microenvironment.

Molecular markers for cervical cancer screening

INTRODUCTION

Cervical cancer remains a significant healthcare problem, notably in low- to middle-income countries. While a negative test for hrHPV has a predictive value of more than 99.5%, its positive predictive value is less than 10% for CIN2+ stages. This makes the use of a so-called triage test indispensable for population-based screening to avoid referring women, that are ultimately at low risk of developing cervical cancer, to a gynecologist. This review will give an overview of tests that are based on epigenetic marker panels and protein markers.

AREAS COVERED

There is a medical need for molecular markers with a better predictive value to discriminate hrHPV-positive women that are at risk of developing cervical cancer from those that are not. Areas covered are epigenetic and protein markers as well as health economic considerations in view of the fact that most cases of cervical cancer arise in low-to-middle-income countries.

EXPERT OPINION

While there are biomarker assays based on changes at the nucleic acid (DNA methylation patterns, miRNAs) and at the protein level, they are not widely used in population screening. Combining nucleic acid-based and protein-based tests could improve the overall specificity for discriminating CIN2+ lesions that carry a low risk of progressing to cervical cancer within the screening interval from those that carry an elevated risk. The challenge is to reduce unnecessary referrals without an undesired increase in false-negative diagnoses resulting in cases of cervical cancer that could have been prevented. A further challenge is to develop tests for low-and middle-income countries, which is critical to reduce the worldwide burden of cervical cancer.

Biliverdin reductase as a target in drug research and development: Facts and hypotheses

Biliverdin reductase-A (BVR) catalyzes the reduction of heme-derived biliverdin into bilirubin, this latter being a powerful endogenous free radical scavenger. Furthermore, BVR is also endowed with both serine/threonine/tyrosine kinase and scaffold activities, through which it interacts with the insulin receptor kinase, conventional and atypical protein kinase C isoforms, mitogen-activated protein kinases as well as the phosphatidylinositol-3 kinase/Akt system. By regulating this complex array of signal transduction pathways, BVR is involved in the pathogenesis of neurodegenerative, metabolic, cardiovascular and immune-inflammatory diseases as well as in cancer. In addition, both BVR and BVR-B, this latter being an alternate isozyme predominant during fetal development but sometimes detectable through adulthood, have been studied as peripheral biomarkers for an early detection of Alzheimer's disease, atherosclerosis and some types of cancer. However, despite these interesting lines of evidence, to date BVR has not been considered as an appealing drug target. Only limited evidence supports the neuroprotective effects of atorvastatin and ferulic acid through BVR regulation in the aged canine brain and human neuroblastoma cells, whereas interesting results have been reported regarding the use of BVR-based peptides in preclinical models of cardiac diseases and cancer.

Structure and function of DEAH-box helicase 32 and its role in cancer

DEAH-box helicase 32 (DHX32) is an RNA helicase with unique structural characteristics that is involved in numerous biological processes associated with RNA, including ribosome biosynthesis, transcription, mRNA splicing and translation. Increasing evidence suggests that abnormal DHX32 expression contributes to cancer initiation and development, due to dysregulated cell proliferation, differentiation, apoptosis and other processes. In the current review, the discovery, structure and function of DHX32, as well as the association between abnormal DHX32 expression and tumors are discussed. DHX32 expression is downregulated in acute lymphoblastic leukemia, but upregulated in solid tumors, including colorectal and breast cancer. Furthermore, DHX32 expression levels are associated with the pathological and clinical features of the cancer. Therefore, DHX32 may serve as a novel liquid biopsy marker for auxiliary diagnosis and prognosis screening, as well as a possible target for cancer therapy. The molecular mechanism underlying the contribution of DHX32 towards the initiation and development of cancer requires further investigation for the development of anticancer treatments based on manipulating DHX32 expression and function.

The critical role of peroxiredoxin-2 in colon cancer stem cells

Colon cancer stem cells (CCSCs) play an important role in facilitating colon cancer occurrence, metastasis and drug resistance. The results of our previous studies confirmed that the well-studied antioxidant gene peroxiredoxin-2 (PRDX2) promotes colon cancer progression. However, the underlying function and mechanisms associated with PRDX2 remodeling in the context of CCSCs have remained poorly studied. In our present study, we demonstrated that PRDX2 is highly expressed in CD133/CD44-positive colon cancer tissues and spheroid CD133+CD44+ CCSCs. PRDX2 overexpression was shown to be closely correlated with CD133+CD44+ CCSCs in colon cancer. Furthermore, PRDX2 depletion markedly suppressed CD133+CD44+ CCSC stemness maintenance, tumor initiation, migration and invasion and liver metastasis. Furthermore, the expression of various EMT markers and Wnt/β-catenin signaling proteins was altered after PRDX2 inhibition. In addition, PRDX2 knockdown led to increased ROS production in CD133+CD44+ CCSCs, sensitizing CCSCs to oxidative stress and chemotherapy. These results suggest that PRDX2 could be a possible therapeutic target in CCSCs.

Heme-Derived Metabolic Signals Dictate Immune Responses

Heme is one of the most abundant molecules in the body acting as the functional core of hemoglobin/myoglobin involved in the O₂/CO₂ carrying in the blood and tissues, redox enzymes and cytochromes in mitochondria. However, free heme is toxic and therefore its removal is a significant priority for the host. Heme is a well-established danger-associated molecular pattern (DAMP), which binds to toll-like receptor 4 (TLR4) to induce immune responses. Heme-derived metabolites including the bile pigments, biliverdin (BV) and bilirubin (BR), were first identified as toxic drivers of neonatal jaundice in 1800 but have only recently been appreciated as endogenous drivers of multiple signaling pathways involved in protection from oxidative stress and regulators of immune responses. The tissue concentration of heme, BV and BR is tightly controlled. Heme oxygenase-1 (HO-1, encoded by HMOX1) produces BV by heme degradation, while biliverdin reductase-A (BLVR-A) generates BR by the subsequent conversion of BV. BLVR-A is a fascinating protein that possesses a classical protein kinase domain, which is activated in response to BV binding to its enzymatic site and initiates the downstream mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways. This links BLVR-A activity to cell growth and survival pathways. BLVR-A also contains a bZip DNA binding domain and a nuclear export sequence (NES) and acts as a transcription factor to regulate the expression of immune modulatory genes. Here we will discuss the role of heme-related immune response and the potential for targeting the heme system for therapies directed toward hepatitis and cancer.

Disruption of the c-Myc/miR-200b-3p/PRDX2 regulatory loop enhances tumor metastasis and chemotherapeutic resistance in colorectal cancer

BACKGROUND

Metastasis is a major threat to colorectal cancer (CRC) patients. We have reported that peroxiredoxin-2 (PRDX2) is associated with CRC invasion and metastasis. However, the mechanisms regulating PRDX2 expression remain unclear. We investigate whether microRNAs (miRNAs) regulate PRDX2 expression in CRC progression.

METHODS

Quantitative real-time polymerase chain reaction (qPCR) was used to measure microRNA-200b-3p (miR-200b-3p) expression. Immunohistochemistry (IHC) was performed to detect c-Myc and PRDX2 protein levels in CRC tissue samples (n = 97). Western blot was used to quantify PRDX2, c-Myc, AKT2/GSK3β pathway-associated proteins and epithelial-mesenchymal transition (EMT)-related proteins in CRC cells. Luciferase reporter assays were used to analyze the interaction between miR-200b-3p and 3'untranslated region (3'UTR) of PRDX2 mRNA and AKT2 mRNA as well as c-Myc and the miR-200b-3p promoter. Chromatin immunoprecipitation (ChIP) assay was used to evaluate binding of c-Myc to the miR-200b-3p promoter. Invasive assay and metastatic model were used to assess invasive and metastatic capacities of CRC cells in vitro and in vivo. Moreover, drug-induced apoptosis was measured by flow cytometry.

RESULTS

We found that miR-200b-3p was significantly downregulated, whereas c-Myc and PRDX2 were upregulated in metastatic CRC cells and CRC tissues compared to their counterparts. An inverse correlation existed between c-Myc and miR-200b-3p, and between miR-200b-3p and PRDX2. We also found that PRDX2 was a target of miR-200b-3p. Importantly, overexpression of nontargetable PRDX2 eliminated the suppressive effects of miR-200b-3p on proliferation, invasion, EMT, chemotherapeutic resistance and metastasis of CRC cells. Moreover, c-Myc bound to the promoter of miR-200b-3p and repressed its transcription. In turn, miR-200b-3p disrupted the stability of c-Myc protein by inducing c-Myc protein threonine 58 (T58) phosphorylation and serine 62 (S62) dephosphorylation via AKT2/GSK3β pathway.

CONCLUSIONS

Our findings reveal that the c-Myc/miR-200b/PRDX2 loop regulates CRC progression and its disruption enhances tumor metastasis and chemotherapeutic resistance in CRC.

The role of peroxiredoxins in cancer

Peroxiredoxins (PRDXs) are a ubiquitously expressed family of small (22–27 kDa) non-seleno peroxidases that catalyze the peroxide reduction of H₂O₂, organic hydroperoxides and peroxynitrite. They are highly involved in the control of various physiological functions, including cell growth, differentiation, apoptosis, embryonic development, lipid metabolism, the immune response, as well as cellular homeostasis. Although the protective role of PRDXs in cardiovascular and neurological diseases is well established, their role in cancer remains controversial. Increasing evidence suggests the involvement of PRDXs in carcinogenesis and in the development of drug resistance. Numerous types of cancer cells, in fact, are characterized by an increase in reactive oxygen species (ROS) production, and often exhibit an altered redox environment compared with normal cells. The present review focuses on the complex association between oxidant balance and cancer, and it provides a brief account of the involvement of PRDXs in tumorigenesis and in the development of chemoresistance.

Proteomic identification of predictive tissue biomarkers of sensitive to neoadjuvant chemotherapy in squamous cervical cancer

AIMS

The regimens of neoadjuvant chemotherapy (NAC) in squamous cervical cancer (SCC) frequently use cisplatin combined with paclitaxel. Unfortunately, some cervical cancers show resistance to the principal chemotherapeutic agents in the treatment, decreasing the effectiveness of this therapy. The objective of this study was to search for predictive markers of response to NAC in patients with SCC.

MAIN METHODS

Two-dimensional gel electrophoresis (2-DE) accompanied by matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS) was used to analyze and identify differentially expressed proteins in ten cases of advanced cervical cancer patients receiving cisplatin-based NAC. Each of these patients received more than two cycles of NAC. Cell proliferation rate in cisplatin resistant human cervical cancer cell Hela/DDP and its parent cell Hela after treatment with Hsp70 inhibitor and/or cisplatin were tested by MTT assay.

KEY FINDINGS

Twelve protein spots changed in abundance, quantitative comparison of spot volumes showed that seven protein spots were up-regulated and five spots were down-regulated in the NAC non-responders compared to the NAC responders. These proteins are involved in various cellular processes essential for cell metabolism, migration and apoptotic signal transduction. The high-fold changes proteins of stathmin1, Hsp70 and pyruvate kinase isoform M2 were validated by Western blot analysis. Over-expression of Hsp70 inhibits the efficacy of cisplatin. Hsp70 inhibitor enhanced the sensitivity to cisplatin in both Hela and Hela/DDP cells.

SIGNIFICANCE

The study found many candidate proteins involved in chemotherapy resistance/sensitivity, among them Hsp70 might be potential biomarkers to predict the efficacy of chemotherapy for SCC patients.

Biliverdin reductase: a target for cancer therapy?

Biliverdin reductase (BVR) is a multifunctional protein that is the primary source of the potent antioxidant, bilirubin. BVR regulates activities/functions in the insulin/IGF-1/IRK/PI3K/MAPK pathways. Activation of certain kinases in these pathways is/are hallmark(s) of cancerous cells. The protein is a scaffold/bridge and intracellular transporter of kinases that regulate growth and proliferation of cells, including PKCs, ERK and Akt, and their targets including NF-κB, Elk1, HO-1, and iNOS. The scaffold and transport functions enable activated BVR to relocate from the cytosol to the nucleus or to the plasma membrane, depending on the activating stimulus. This enables the reductase to function in diverse signaling pathways. And, its expression at the transcript and protein levels are increased in human tumors and the infiltrating T-cells, monocytes and circulating lymphocytes, as well as the circulating and infiltrating macrophages. These functions suggest that the cytoprotective role of BVR may be permissive for cancer/tumor growth. In this review, we summarize the recent developments that define the pro-growth activities of BVR, particularly with respect to its input into the MAPK signaling pathway and present evidence that BVR-based peptides inhibit activation of protein kinases, including MEK, PKCδ, and ERK as well as downstream targets including Elk1 and iNOS, and thus offers a credible novel approach to reduce cancer cell proliferation.

Expression pattern of the PRDX2, RAB1A, RAB1B, RAB5A and RAB25 genes in normal and cancer cervical tissues

Cervical cancer is the second most prevalent malignancy among women worldwide, and additional objective diagnostic markers for this disease are needed. Given the link between cancer development and alternative splicing, we aimed to analyze the splicing patterns of the PRDX2, RAB1A, RAB1B, RAB5A and RAB25 genes, which are associated with different cancers, in normal cervical tissue, preinvasive cervical lesions and invasive cervical tumors, to identify new objective diagnostic markers. Biopsies of normal cervical tissue, preinvasive cervical lesions and invasive cervical tumors, were subjected to rapid amplification of cDNA 3' ends (3' RACE) RT‑PCR. Resulting PCR products were analyzed on agarose gels, gel‑purified and sequenced. Normal cervical tissue, preinvasive cervical lesions and invasive cervical tumors contained one PCR product corresponding to full‑length PRDX2, RAB5A and RAB25 transcripts. All tissues contained two RAB1A‑specific PCR products corresponding to the full‑length transcript and one new alternatively spliced RAB1A transcript. Invasive cervical tumors contained one PCR product corresponding to the full‑length RAB1B transcript, while all normal cervical tissue and preinvasive cervical lesions contained both the full‑length RAB1B transcript and three new alternatively spliced RAB1B transcripts. Alternative splicing of the RAB1A transcript occurs in all cervical tissues, while alternative splicing of the RAB1B transcript occurs in normal cervical tissue and in preinvasive cervical lesions; not in invasive cervical tumors.

Epigenomic characterization of locally advanced anal cancer: a radiation therapy oncology group 98-11 specimen study

BACKGROUND

The Radiation Therapy Oncology Group 98-11 clinical trial demonstrated the superiority of standard 5-fluorouracil/mitomycin-C over 5-fluorouracil/cisplatin in combination with radiation in the treatment of anal squamous cell cancer. Tumor size (>5 cm) and lymph node metastases are associated with disease progression. There may be key molecular differences (eg, DNA methylation changes) in tumors at high risk for progression.

OBJECTIVE

The objectives of this study were to determine whether there are differences in DNA methylation at individual CpG sites and within genes among locally advanced anal cancers, with large tumor size and/or nodal involvement, compared with those that are less advanced.

DESIGN

This was a case-case study among 121 patients defined as high risk (tumor size >5 cm and/or nodal involvement; n = 59) or low risk (≤5 cm, node negative; n = 62) within the mitomycin-C arm of the Radiation Therapy Oncology Group 98-11 trial. DNA methylation was measured using the Illumina HumanMethylation450 Array.

SETTINGS

The study was conducted in a tertiary care cancer center in collaboration with a national clinical trials cooperative group.

PATIENTS

The patients consisted of 74 women and 47 men with a median age of 54 years (range, 25-79 years).

MAIN OUTCOME MEASURES

DNA methylation differences at individual CpG sites and within genes between low- and high-risk patients were compared using the Mann-Whitney test (p < 0.001).

RESULTS

A total of 16 CpG loci were differentially methylated (14 increased and 2 decreased) in high- versus low-risk cases. Genes harboring differentially methylated CpG sites included known tumor suppressor genes and novel targets.

LIMITATIONS

This study only included patients in the mitomycin-C arm with tumor tissue; however, this sample was representative of the trial.

CONCLUSIONS

This is the first study to apply genome-wide methylation analysis to anal cancer. Biologically relevant differences in methylated targets were found to discriminate locally advanced from early anal cancer. Epigenetic events likely play a significant role in the progression of anal cancer and may serve as potential biomarkers.

Expression and function of Annexin II in lung cancer tissue

OBJECTIVE

To explore the expression of Annexin II and its relationship with the cell differentiation, proliferation in lung cancer.

METHODS

RT-PCR and Western blot assays were used to detect the expression of Annexin II in lung cancer tissues and cell lines.

RESULTS

Annexin II was significantly up-regulated in lung cancer tissues, and in lung cancer cell lines, Annexin II had higher mRNA and protein expressions.

CONCLUSIONS

Annexin II is up-regulated in lung cancer, suggesting that the Annexin II has a potential value in the human lung cancer.

Perturbations of RNA helicases in cancer

Helicases are implicated in most stages of the gene expression pathway, ranging from DNA replication, RNA transcription, splicing, RNA transport, ribosome biogenesis, mRNA translation, RNA storage and decay. These enzymes utilize energy derived from nucleotide triphosphate hydrolysis to remodel ribonucleoprotein complexes, RNA, or DNA and in this manner affect the information content or output of RNA. Several RNA helicases have been implicated in the oncogenic process--either through altered expression levels, mutations, or due to their role in pathways required for tumor initiation, progression, maintenance, or chemosensitivity. The purpose of this review is to highlight those RNA helicases for which there is significant evidence implicating them in cancer biology.

Prognostic Significance of Cell Cycle- and Invasion-Related Molecular Markers and Genomic Instability in Primary Carcinoma of the Vagina

Objective

This study aimed to analyze the prognostic value of DNA content and biological markers for cell cycle regulation and invasion in primary carcinoma of the vagina (PCV).

Material and Methods

Seventy-two consecutive patients with PCV, categorized as short-term (≤2 years) and long-term (≥8 years) survivors, were evaluated for DNA content by image cytometry, and for expression of p53, p21, cyclin A, Ki67, E-cadherin, and laminin-5γ2 chain by immunohistochemistry. The relationship between these biological markers and histopathological and clinical parameters was assessed.

Results

All PCV showed aneuploid DNA content. Most of the PCV patients showed no overexpression of p53 and high expression of p21, cyclin A, and Ki67. Loss or underexpression of E-cadherin was found in 94% (68/72) of PCV patients, and all patients showed immunopositivity for the laminin-5γ2 chain. Tumors with a vaginal longitudinal location in the lower third or in the entire vagina more often had overexpression of p53, high expression of Ki67 (P = 0.044), and underexpression of E-cadherin (P = 0.038), than tumors confined only to the upper third. Overexpression of p53 was significantly associated with short-term survival in the univariate analysis, but not in the multivariate analysis adjusted for age at diagnosis and tumor size.

Conclusions

The expression level of some markers was related to tumor location, which might be indicative of different genesis. Overexpression of p53 was associated with short-term survival, but the only independent predictors of survival were age at diagnosis and tumor size.

Proteomic profiling of follicular and papillary thyroid tumors

OBJECTIVE

Thyroid proteomics is a new direction in thyroid cancer research aiming at etiological understanding and biomarker identification for improved diagnosis.

METHODS

Two-dimensional electrophoresis was applied to cytosolic protein extracts from frozen thyroid samples (ten follicular adenomas, nine follicular carcinomas, ten papillary carcinomas, and ten reference thyroids). Spots with differential expression were revealed by image and multivariate statistical analyses, and identified by mass spectrometry.

RESULTS

A set of 25 protein spots significant for discriminating between the sample groups was identified. Proteins identified for nine of these spots were studied further including 14-3-3 protein beta/alpha, epsilon, and zeta/delta, peroxiredoxin 6, selenium-binding protein 1, protein disulfide-isomerase precursor, annexin A5 (ANXA5), tubulin alpha-1B chain, and α1-antitrypsin precursor. This subset of protein spots carried the same predictive power in differentiating between follicular carcinoma and adenoma or between follicular and papillary carcinoma, as compared with the larger set of 25 spots. Protein expression in the sample groups was demonstrated by western blot analyses. For ANXA5 and the 14-3-3 proteins, expression in tumor cell cytoplasm was demonstrated by immunohistochemistry both in the sample groups and an independent series of papillary thyroid carcinomas.

CONCLUSION

The proteins identified confirm previous findings in thyroid proteomics, and suggest additional proteins as dysregulated in thyroid tumors.

Impact of genomic stability on protein expression in endometrioid endometrial cancer

Background:

Genomic stability is one of the crucial prognostic factors for patients with endometrioid endometrial cancer (EEC). The impact of genomic stability on the tumour tissue proteome of EEC is not yet well established.

Methods:

Tissue lysates of EEC, squamous cervical cancer (SCC), normal endometrium and squamous cervical epithelium were subjected to two-dimensional (2D) gel electrophoresis and identification of proteins by MALDI TOF MS. Expression of selected proteins was analysed in independent samples by immunohistochemistry.

Results:

Diploid and aneuploid genomically unstable EEC displayed similar patterns of protein expression. This was in contrast to diploid stable EEC, which displayed a protein expression profile similar to normal endometrium. Approximately 10% of the differentially expressed proteins in EEC were specific for this type of cancer with differential expression of other proteins observed in other types of malignancy (e.g., SCC). Selected proteins differentially expressed in 2D gels of EEC were further analysed in an EEC precursor lesion, that is, atypical hyperplasia of endometrium, and showed increased expression of CLIC1, EIF4A1 and PRDX6 and decreased expression of ENO1, ANXA4, EMD and Ku70.

Conclusion:

Protein expression in diploid and aneuploid genomically unstable EEC is different from the expression profile of proteins in diploid genomically stable EEC. We showed that changes in expression of proteins typical for EEC could already be detected in precursor lesions, that is, atypical hyperplasia of endometrium, highlighting their clinical potential for improving early diagnostics of EEC.

Discrimination of grade 2 and 3 cervical intraepithelial neoplasia by means of analysis of water soluble proteins recovered from cervical biopsies

Background

Cervical intraepithelial neoplasia (CIN) grades 2 and 3 are usually grouped and treated in the same way as "high grade", in spite of their different risk to cancer progression and spontaneous regression rates. CIN2-3 is usually diagnosed in formaldehyde-fixed paraffin embedded (FFPE) punch biopsies. This procedure virtually eliminates the availability of water-soluble proteins which could have diagnostic and prognostic value.

Aim

To investigate whether a water-soluble protein-saving biopsy processing method followed by a proteomic analysis of supernatant samples using LC-MS/MS (LTQ Orbitrap) can be used to distinguish between CIN2 and CIN3.

Methods

Fresh cervical punch biopsies from 20 women were incubated in RPMI1640 medium for 24 hours at 4°C for protein extraction and subsequently subjected to standard FFPE processing. P16 and Ki67-supported histologic consensus review CIN grade (CIN2, n = 10, CIN3, n = 10) was assessed by independent gynecological pathologists. The biopsy supernatants were depleted of 7 high abundance proteins prior to uni-dimensional LC-MS/MS analysis for protein identifications.

Results

The age of the patients ranged from 25-40 years (median 29.7), and mean protein concentration was 0.81 mg/ml (range 0.55 - 1.14). After application of multistep identification criteria, 114 proteins were identified, including proteins like vimentin, actin, transthyretin, apolipoprotein A-1, Heat Shock protein beta 1, vitamin D binding protein and different cytokeratins. The identified proteins are annotated to metabolic processes (36%), signal transduction (27%), cell cycle processes (15%) and trafficking/transport (9%). Using binary logistic regression, Cytokeratin 2 was found to have the strongest independent discriminatory power resulting in 90% overall correct classification.

Conclusions

114 proteins were identified in supernatants from fresh cervical biopsies and many differed between CIN2 and 3. Cytokeratin 2 is the strongest discriminator with 90% overall correct classifications.

The role of annexin A2 in tumorigenesis and cancer progression

Annexin A2 is a calcium-dependent, phospholipid-binding protein found on various cell types. It is up-regulated in various tumor types and plays multiple roles in regulating cellular functions, including angiogenesis, proliferation, apoptosis, cell migration, invasion and adhesion. Annexin A2 binds with plasminogen and tissue plasminogen activator on the cell surface, which leads to the conversion of plasminogen to plasmin. Plasmin is a serine protease which plays a key role in the activation of metalloproteinases and degradation of extracellular matrix components essential for metastatic progression. We have recently found that both annexin A2 and plasmin are increased in conditioned media of co cultured ovarian cancer and peritoneal cells. Our studies suggest that annexin A2 is part of a tumor-host signal pathway between ovarian cancer and peritoneal cells which promotes ovarian cancer metastasis. Accumulating evidence suggest that interactions between annexin A2 and its binding proteins play an important role in the tumor microenvironment and act together to enhance cancer metastasis. This article reviews the current knowledge on the biological role of annexin A2 and its binding proteins in solid malignancies including ovarian cancer.

Differential expression of ANXA6, HSP27, PRDX2, NCF2, and TPM4 during uterine cervix carcinogenesis: diagnostic and prognostic value

Background:

Cytology-based diagnostics of squamous cervical cancer (SCC) precursor lesions is subjective and can be improved by objective markers.

Methods:

IHC-based analysis of ANXA6, HSP27, peroxiredoxin 2 (PRDX2), NCF2, and tropomyosin 4 (TPM4) during SCC carcinogenesis.

Results:

Expression of ANXA6, HSP27, PRDX2, and NCF2 in the cytoplasm of dysplastic cells increased from cervical intraepithelial neoplasia 2/3 (CIN2/3) to microinvasive cancer. Invasive SCC showed lower expression of TPM4 than CIN and normal epithelium. CIN2/3 with the highest sensitivity and specificity differed from normal epithelium by cytoplasmic expression of HSP27. Patients with cytoplasmic HSP27 expression in SCC deviating from that observed in normal epithelium had worse relapse-free (P=0.019) and overall (P=0.014) survival. Invasive SCC with the highest sensitivity and specificity differed from normal epithelium by expression of PRDX2 and TPM4 in the cytoplasm, from CIN2/3 by the expression of ANXA6 and TPM4 in the cytoplasm, and from microinvasive SCC by the expression of PRDX2 and ANXA6 in the cytoplasm. The number of sporadic ANXA6+ cells between the atypical cells increased from CIN2/3 to invasive SCC.

Conclusion:

Detection of expression changes of the proteins ANXA6, HSP27, PRDX2, NCF2, and TPM4 in SCC precursor lesions may aid current cytological and pathological diagnostics and evaluation of prognosis.

Filamin A mediates interactions between cytoskeletal proteins that control cell adhesion

Cell adhesion, spreading and migration on extracellular matrices are regulated by complex processes that involve the cytoskeleton and a large array of adhesion receptors, including the β1 integrin. Filamin A is a large, multi-domain, homodimeric actin binding protein that contributes to the mechanical stability of cells and interacts with several proteins that regulate cell adhesion including β1 integrin and several protein kinases. Here we review current data on the structure, mechanical properties and intracellular signaling functions of filamin that regulate cell adhesion. We also consider new data showing that interactions of filamin A with intermediate filaments and protein kinase C enable tight regulation of β1 integrin function and consequently early events in cell adhesion and migration on extracellular matrix proteins.

Diagnostic value and prognostic significance of plasmatic proteasome level in patients with melanoma

Plasmatic proteasome (p-proteasome) also called circulating proteasome has recently been described as a tumor marker. We investigated the diagnostic and prognostic accuracies of p-proteasome levels in a melanoma population classified according to the American Joint Committee on Cancer staging system. Using an ELISA test, we measured p-proteasome levels in 90 patients and 40 controls between March 2003 and March 2008. The subunit composition of p-proteasomes was determined in metastatic melanoma by proteomic analysis. The mean p-proteasome levels were correlated with stages (P < 0.0001; r(S) = 0.664). They were significantly higher in patients with stage IV and stage III with lymph node metastasis (9187 ± 1294 and 5091 ± 454 ng/ml, respectively) compared to controls (2535 ± 187 ng/ml; P < 0.001), to stage I/II (2864 ± 166 ng/ml; P < 0.001) and to stage III after curative lymphadenectomy (2859 ± 271 ng/ml; P < 0.001). The diagnostic accuracy of p-proteasome was evaluated by receiver operating characteristic analysis. With a cut-off of 4300 ng/ml, diagnostic specificity and sensitivity of p-proteasome for regional or visceral metastases were respectively 96.3% and 72.2%. In univariate analysis, high p-proteasome levels (>4300 ng/ml) were significantly correlated with an increased risk of progression [hazard ratio (HR) = 7.34; 95% CI 3.54-15.21, P < 0.0001] and a risk of death (HR = 5.92; 95% CI 2.84-12.33, P < 0.0001). In multivariate analysis, high p-proteasome levels were correlated with a poorer clinical outcome in the subgroup analysis limited to patients with disease stages I, II and III. Proteomic analysis confirmed the presence of all proteasome and immunoproteasome subunits. Taken together, these results indicate that p-proteasomes are a new marker for metastatic dissemination in patients with melanoma.

Human transcriptome nexuses: basic-eukaryotic and metazoan

Using a new approach, I analysed human transcriptome coexpression network and revealed two large-scale nexuses. Besides gene coexpression, each nexus is characterized by a combination of gene evolutionary origin, function and among-tissues expression breadth. The first nexus contains mostly genes of pre-metazoan origin, which are widely expressed and have cell-centred functions. The second nexus is enriched in genes of metazoan origin, which are expressed more narrowly and have organism-centred functions. The revealed nexuses are supported by asymmetry in distribution of transcription factor targets between them. Within the metazoan nexus, there is a subnexus that is more pronounced in the nervous tissues and is enriched in gene regulatory complexity. It mostly contains genes related to nervous system, cell communication and multicellular organism processes and development. The revealed nexuses indicate a dichotomy in the transcriptional regulation and can provide a framework for further functional genomics studies.

Characterization of the Human Cervical Mucous Proteome

Introduction

Cervical cancer is among the most common cancers in women worldwide. Discovery of biomarkers for the early detection of cervical cancer would improve current screening practices and reduce the burden of disease.

Objective

In this study, we report characterization of the human cervical mucous proteome as the first step towards protein biomarker discovery.

Methods

The protein composition was characterized using one- and two-dimensional gel electrophoresis, and liquid chromatography coupled with mass spectrometry. We chose to use this combination of traditional biochemical techniques and proteomics to allow a more comprehensive analysis.

Results and Conclusion

A total of 107 unique proteins were identified, with plasma proteins being most abundant. These proteins represented the major functional categories of metabolism, immune response, and cellular transport. Removal of high molecular weight abundant proteins by immunoaffinity purification did not significantly increase the number of protein spots resolved. We also analyzed phosphorylated and glycosylated proteins by fluorescent post-staining procedures. The profiling of cervical mucous proteins and their post-translational modifications can be used to further our understanding of the cervical mucous proteome.