Anti-alpha-enolase autoantibodies are down-regulated in advanced cancer patients

Single-cell dissection reveals promotive role of ENO1 in leukemia stem cell self-renewal and chemoresistance in acute myeloid leukemia

BACKGROUND

Quiescent self-renewal of leukemia stem cells (LSCs) and resistance to conventional chemotherapy are the main factors leading to relapse of acute myeloid leukemia (AML). Alpha-enolase (ENO1), a key glycolytic enzyme, has been shown to regulate embryonic stem cell differentiation and promote self-renewal and malignant phenotypes in various cancer stem cells. Here, we sought to test whether and how ENO1 influences LSCs renewal and chemoresistance within the context of AML.

METHODS

We analyzed single-cell RNA sequencing data from bone marrow samples of 8 relapsed/refractory AML patients and 4 healthy controls using bioinformatics and machine learning algorithms. In addition, we compared ENO1 expression levels in the AML cohort with those in 37 control subjects and conducted survival analyses to correlate ENO1 expression with clinical outcomes. Furthermore, we performed functional studies involving ENO1 knockdown and inhibition in AML cell line.

RESULTS

We used machine learning to model and infer malignant cells in AML, finding more primitive malignant cells in the non-response (NR) group. The differentiation capacity of LSCs and progenitor malignant cells exhibited an inverse correlation with glycolysis levels. Trajectory analysis indicated delayed myeloid cell differentiation in NR group, with high ENO1-expressing LSCs at the initial stages of differentiation being preserved post-treatment. Simultaneously, ENO1 and stemness-related genes were upregulated and co-expressed in malignant cells during early differentiation. ENO1 level in our AML cohort was significantly higher than the controls, with higher levels in NR compared to those in complete remission. Knockdown of ENO1 in AML cell line resulted in the activation of LSCs, promoting cell differentiation and apoptosis, and inhibited proliferation. ENO1 inhibitor can impede the proliferation of AML cells. Furthermore, survival analyses associated higher ENO1 expression with poorer outcome in AML patients.

CONCLUSIONS

Our findings underscore the critical role of ENO1 as a plausible driver of LSC self-renewal, a potential target for AML target therapy and a biomarker for AML prognosis.

High Expression of ENO1 and Low Levels of Circulating Anti-ENO1 Autoantibodies in Patients with Myelodysplastic Neoplasms and Acute Myeloid Leukaemia

In solid tumours, high expression of the glycolytic enzyme, α-enolase (ENO1), predicts for poor patient overall survival (OS), and circulating autoantibodies to ENO1 correlate positively with diagnosis and negatively with advanced disease. Although ENO1 is one of the most highly expressed genes in acute myeloid leukaemia (AML), its potential role as a biomarker in AML or its precursor, myelodysplastic neoplasms (MDS), has not been investigated. A meta-analysis of nine AML online datasets (n = 1419 patients) revealed that high ENO1 expression predicts for poor OS (HR = 1.22, 95% CI: 1.10-1.34, p < 0.001). Additionally, when compared to AML in remission (n = 5), ENO1 protein detected by immunohistochemistry was significantly higher at diagnosis in bone marrow from both AML (n = 5, p < 0.01) and MDS patients (n = 12, p < 0.05), and did not correlate with percentage of blasts (r = 0.28, p = 0.21). AML patients (n = 34) had lower circulating levels of ENO1 autoantibodies detected by ELISA compared to 26 MDS and 18 controls (p = 0.003). However, there was no difference in OS between AML patients with high vs. low levels of anti-ENO1 autoantibodies (p = 0.77). BM immunostaining for ENO1 and patient monitoring of anti-ENO1 autoantibody levels may be useful biomarkers for MDS and AML.

Identification of Enolase 1 as a Potential Target for Magnaporthe oryzae: Integrated Proteomic and Molecular Dynamics Simulation

Rice blast is an essential factor affecting rice yield and quality, which is caused by Magnaporthe oryzae (M. oryzae). Isobavachalcone (IBC) is a botanical fungicide derived from the seed extract of the Leguminosae plant Psoralea corylifolia L. and has shown an excellent rice blast control effect in field applications. To explore the potential targets of rice blast control, the analysis of the differentially expressed proteins (DEPs) between the liquid culture medium of mycelium treated by 10 mg/L of IBC for 2 h and the control group indicated that Enolase 1 (ENO1) was the most significantly down-regulated DEP with a fold change value of 0.305. In vitro experiments showed that after treating liquid culture mycelium with 10 mg/L of IBC for 0.5, 1, 2, 4, and 8 h, the enzymatic activity of ENO1 in the IBC experimental groups was 0.97, 0.75, 0.52, 0.44, and 0.39 times as much as in the control groups, respectively. To further explore the molecular interaction and binding mode between IBC and ENO1, the three-dimensional structure of ENO1 was established based on homology modeling. Molecular docking and molecular dynamics simulation showed that IBC had a pi-pi stacking effect with the residue TYR_365, a hydrogen bond interaction with the residue ARG_393, and hydrophobic interactions with non-polar residues ALA_361, LYS_362, and VAL_371 of ENO1. These findings indicated that ENO1 is a potential target of M. oryzae, which would pave the way for screening novel effective fungicides targeting ENO1.

Revisited Metabolic Control and Reprogramming Cancers by Means of the Warburg Effect in Tumor Cells

Aerobic glycolysis is an emerging hallmark of many human cancers, as cancer cells are defined as a "metabolically abnormal system". Carbohydrates are metabolically reprogrammed by its metabolizing and catabolizing enzymes in such abnormal cancer cells. Normal cells acquire their energy from oxidative phosphorylation, while cancer cells acquire their energy from oxidative glycolysis, known as the "Warburg effect". Energy-metabolic differences are easily found in the growth, invasion, immune escape and anti-tumor drug resistance of cancer cells. The glycolysis pathway is carried out in multiple enzymatic steps and yields two pyruvate molecules from one glucose (Glc) molecule by orchestral reaction of enzymes. Uncontrolled glycolysis or abnormally activated glycolysis is easily observed in the metabolism of cancer cells with enhanced levels of glycolytic proteins and enzymatic activities. In the "Warburg effect", tumor cells utilize energy supplied from lactic acid-based fermentative glycolysis operated by glycolysis-specific enzymes of hexokinase (HK), keto-HK-A, Glc-6-phosphate isomerase, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase, phosphofructokinase (PFK), phosphor-Glc isomerase (PGI), fructose-bisphosphate aldolase, phosphoglycerate (PG) kinase (PGK)1, triose phosphate isomerase, PG mutase (PGAM), glyceraldehyde-3-phosphate dehydrogenase, enolase, pyruvate kinase isozyme type M2 (PKM2), pyruvate dehydrogenase (PDH), PDH kinase and lactate dehydrogenase. They are related to glycolytic flux. The key enzymes involved in glycolysis are directly linked to oncogenesis and drug resistance. Among the metabolic enzymes, PKM2, PGK1, HK, keto-HK-A and nucleoside diphosphate kinase also have protein kinase activities. Because glycolysis-generated energy is not enough, the cancer cell-favored glycolysis to produce low ATP level seems to be non-efficient for cancer growth and self-protection. Thus, the Warburg effect is still an attractive phenomenon to understand the metabolic glycolysis favored in cancer. If the basic properties of the Warburg effect, including genetic mutations and signaling shifts are considered, anti-cancer therapeutic targets can be raised. Specific therapeutics targeting metabolic enzymes in aerobic glycolysis and hypoxic microenvironments have been developed to kill tumor cells. The present review deals with the tumor-specific Warburg effect with the revisited viewpoint of recent progress.

Tissue-Based Proteomic Profiling in Patients with Hyperplasia and Endometrial Cancer

Uterine cancers are among the most prevalent gynecological malignancies, and endometrial cancer (EC) is the most common in this group. This study used tissue-based proteomic profiling analysis in patients with endometrial cancer and hyperplasia, and control patients. Conventional 2D gel electrophoresis, followed by a mass spectrometry approach with bioinformatics, including a network pathway analysis pipeline, was used to identify differentially expressed proteins and associated metabolic pathways between the study groups. Thirty-six patients (twelve with endometrial cancer, twelve with hyperplasia, and twelve controls) were enrolled in this study. The mean age of the participants was 46–75 years. Eighty-seven proteins were significantly differentially expressed between the study groups, of which fifty-three were significantly differentially regulated (twenty-eight upregulated and twenty-five downregulated) in the tissue samples of EC patients compared to the control (Ctrl). Furthermore, 26 proteins were significantly dysregulated (8 upregulated and 18 downregulated) in tissue samples of hyperplasia (HY) patients compared to Ctrl. Thirty-two proteins (nineteen upregulated and thirteen downregulated) including desmin, peptidyl prolyl cis-trans isomerase A, and zinc finger protein 844 were downregulated in the EC group compared to the HY group. Additionally, fructose bisphosphate aldolase A, alpha enolase, and keratin type 1 cytoskeletal 10 were upregulated in the EC group compared to those in the HY group. The proteins identified in this study were known to regulate cellular processes (36%), followed by biological regulation (16%). Ingenuity pathway analysis found that proteins that are differentially expressed between EC and HY are linked to AKT, ACTA2, and other signaling pathways. The panels of protein markers identified in this study could be used as potential biomarkers for distinguishing between EC and HY and early diagnosis and progression of EC from hyperplasia and normal patients.

ENO1 and Cancer

α-Enolase (ENO1), also known as 2-phospho-D-glycerate hydrolase, is a glycolytic enzyme that catalyzes the conversion of 2-phosphoglyceric acid to phosphoenolpyruvic acid during glycolysis. It is a multifunctional oncoprotein that is present both in cell surface and cytoplasm, contributing to hit seven out of ten “hallmarks of cancer.” ENO1's glycolytic function deregulates cellular energetic, sustains tumor proliferation, and inhibits cancer cell apoptosis. Moreover, ENO1 evades growth suppressors and helps tumors to avoid immune destruction. Besides, ENO1 “moonlights” on the cell surface and acts as a plasminogen receptor, promoting cancer invasion and metastasis by inducing angiogenesis. Overexpression of ENO1 on a myriad of cancer types together with its localization on the tumor surface makes it a great prognostic and diagnostic cancer biomarker as well as an accessible oncotherapeutic target. This review summarizes the up-to-date knowledge about the relationship between ENO1 and cancer, examines ENO1's potential as a cancer biomarker, and discusses ENO1's role in novel onco-immunotherapeutic strategies.

An auto-antibody identified from phenotypic directed screening platform shows host immunity against EV-A71 infection

Background

Enterovirus A71 (EV-A71) is a neurotropic virus which may cause severe neural complications, especially in infants and children. The clinical manifestations include hand-foot-and-mouth disease, herpangina, brainstem encephalitis, pulmonary edema, and other severe neurological diseases. Although there are some vaccines approved, the post-marketing surveillance is still unavailable. In addition, there is no antiviral drugs against EV-A71 available.

Methods

In this study, we identified a novel antibody that could inhibit viral growth through a human single chain variable fragment (scFv) library expressed in mammalian cells and panned by infection with lethal dose of EV-A71.

Results

We identified that the host protein α-enolase (ENO1) is the target of this scFv, and anti-ENO1 antibody was found to be more in mild cases than severe EV-A71 cases. Furthermore, we examined the antiviral activity in a mouse model. We found that the treatment of the identified 07-human IgG₁ antibody increased the survival rate after virus challenge, and significantly decreased the viral RNA and the level of neural pathology in brain tissue.

Conclusions

Collectively, through a promising intracellular scFv library expression and screening system, we found a potential scFv/antibody which targets host protein ENO1 and can interfere with the infection of EV-A71. The results indicate that the usage and application of this antibody may offer a potential treatment against EV-A71 infection.

Enolase 1, a Moonlighting Protein, as a Potential Target for Cancer Treatment

Enolase 1 (ENO1) is a moonlighting protein, function as a glycolysis enzyme, a plasminogen receptor and a DNA binding protein. ENO1 play an important role in the process of cancer development. The transcription, translation, post-translational modifying activities and the immunoregulatory role of ENO1 at the cancer development is receiving increasing attention. Some function model studies have shown that ENO1 is a potential target for cancer treatment. In this review, we provide a comprehensive overview of the characterization, function, related transduction cascades of ENO1 and its roles in the pathophysiology of cancers, which is a consequence of ENO1 signaling dysregulation. And the development of novels anticancer agents that targets ENO1 may provide a more attractive option for the treatment of cancers. The data of sarcoma and functional cancer models indicates that ENO1 may become a new potential target for anticancer therapy.

Alpha-Enolase: Emerging Tumor-Associated Antigen, Cancer Biomarker, and Oncotherapeutic Target

Alpha-enolase, also known as enolase-1 (ENO1), is a glycolytic enzyme that “moonlights” as a plasminogen receptor in the cell surface, particularly in tumors, contributing to cancer cell proliferation, migration, invasion, and metastasis. ENO1 also promotes other oncogenic events, including protein-protein interactions that regulate glycolysis, activation of signaling pathways, and resistance to chemotherapy. ENO1 overexpression has been established in a broad range of human cancers and is often associated with poor prognosis. This increased expression is usually accompanied by the generation of anti-ENO1 autoantibodies in some cancer patients, making this protein a tumor associated antigen. These autoantibodies are common in patients with cancer associated retinopathy, where they exert pathogenic effects, and may be triggered by immunodominant peptides within the ENO1 sequence or by posttranslational modifications. ENO1 overexpression in multiple cancer types, localization in the tumor cell surface, and demonstrated targetability make this protein a promising cancer biomarker and therapeutic target. This mini-review summarizes our current knowledge of ENO1 functions in cancer and its growing potential as a cancer biomarker and guide for the development of novel anti-tumor treatments.

Immunoproteomics approach revealed elevated autoantibody levels against ANXA1 in early stage gallbladder carcinoma

BACKGROUND

Early diagnosis is important for the timely treatment of gallbladder carcinoma (GBC) patients and may lead to increased survival outcomes. Here, we have applied serological proteome analysis (SERPA), an immunoproteomics approach, for the detection of 'tumor-associated antigens (TAAs) that elicit humoral response' in early stage GBC patients.

METHODS

Total protein from pooled tumor tissue of GBC patients (n = 7) was resolved by two-dimensional gel electrophoresis (2-DE) followed by immunoblotting using pooled blood plasma from healthy volunteers (n = 11) or gallstone disease (GSD) cases (n = 11) or early stage GBC (Stage I and II) (n = 5) or GBC stage IIIA (n = 9). 2-D gel and immunoblot images were acquired and analyzed using PDQuest software to identify immunoreactive spots in GBC cases in comparison to controls. Proteins from immunoreactive spots were identified by liquid chromatography- tandem mass spectrometric analysis (LC-MS/MS). Autoantibody levels for two of the functionally relevant proteins were investigated in individual plasma samples (52 cases and 89 controls) by dot blot assay using recombinant proteins.

RESULTS

Image analysis using PDQuest software identified 25 protein spots with significantly high or specific immunoreactivity in GBC cases. Mass spectrometric analysis of 8 corresponding protein spots showing intense immunoreactivity (based on densitometric analysis) in early stage GBC or GBC stage IIIA cases led to the identification of 27 proteins. Some of the identified proteins include ANXA1, HSPD1, CA1, CA2, ALDOA and CTSD. Among the two proteins, namely ANXA1 and HSPD1 verified using a cohort of samples, significantly elevated autoantibody levels against ANXA1 were observed in early stage GBC cases in comparison to healthy volunteers or GSD cases (unpaired t-test, p < 0.05). Receiver operating characteristic (ROC) curve analysis for ANXA1 showed an Area under the Curve (AUC) of 0.69, with 41.7% sensitivity against a specificity of 89.9% for early stage GBC. IHC analysis for ANXA1 protein showed 'high' expression levels in 72% of GBC cases whereas all the controls showed 'low' expression levels.

CONCLUSIONS

The study suggests that the ANXA1 autoantibody levels against ANXA1 may be potentially employed for early stage detection of GBC patients. Other proteins could also be explored and verified in a large cohort of clinical samples.

Exploring the Proteomic Alterations from Untreated and Cryoablation and Irradiation Treated Giant Cell Tumors of Bone Using Liquid-Chromatography Tandem Mass Spectrometry

Giant cell tumors of bone (GCT) are benign tumors that show a locally aggressive nature and affect bones' architecture. Recently, cryoablation and irradiation treatments have shown promising results in GCT patients with faster recovery and less recurrence and metastasis. Therefore, it became a gold standard surgical treatment for patients. Hence, we have compared GCT-untreated, cryoablation, and irradiation-treated samples to identify protein alterations using high-frequency liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Our label-free quantification analysis revealed a total of 107 proteins (p < 0.01) with 26 up-regulated (< 2-folds to 5-fold), and 81 down-regulated (> 0.1 to 0.5 folds) proteins were identified from GCT-untreated and treated groups. Based on pathway analysis, most of the identified up-regulated proteins involved in critical metabolic functions associated with tumor proliferation, angiogenesis, and metastasis. On the other hand, the down-regulated proteins involved in glycolysis, tumor microenvironment, and apoptosis. The observed higher expressions of matrix metalloproteinase 9 (MMP9) and TGF-beta in the GCT-untreated group associated with bones' osteolytic process. Interestingly, both the proteins showed reduced expressions after cryoablation treatment, and contrast expressions identified in the irradiation treated group. Therefore, these expressions were confirmed by immunoblot analysis. In addition to these, several glycolytic enzymes, immune markers, extracellular matrix (ECM), and heat shock proteins showed adverse expressions in the GCT-untreated group were identified with favorable regulations after treatment. Therefore, the identified expression profiles will provide a better picture of treatment efficacy and effect on the molecular environment of GCT.

Enolase 1 regulates stem cell-like properties in gastric cancer cells by stimulating glycolysis

Recent studies have demonstrated that gastric cancer stem cells (CSCs) are a rare sub-group of gastric cancer (GC) cells and have an important role in promoting the tumor growth and progression of GC. In the present study, we demonstrated that the glycolytic enzyme Enolase 1 (ENO1) was involved in the regulation of the stem cell-like characteristics of GC cells, as compared to the parental cell lines PAMC-82 and SNU16, the expression of ENO1 in spheroids markedly increased. We then observed that ENO1 could enhance stem cell-like characteristics, including self-renewal capacity, cell invasion and migration, chemoresistance, and even the tumorigenicity of GC cells. ENO1 is known as an enzyme that is involved in glycolysis, but our results showed that ENO1 could markedly promote the glycolytic activity of cells. Furthermore, inhibiting glycolysis activity using 2-deoxy-D-glucose treatment significantly reduced the stemness of GC cells. Therefore, ENO1 could improve the stemness of CSCs by enhancing the cells' glycolysis. Subsequently, to further confirm our results, we found that the inhibition of ENO1 using AP-III-a4 (ENOblock) could reduce the stemness of GC cells to a similar extent as the knockdown of ENO1 by shRNA. Finally, increased expression of ENO1 was related to poor prognosis in GC patients. Taken together, our results demonstrated that ENO1 is a significant biomarker associated with the stemness of GC cells.

Enhancement of diagnostic performance in lung cancers by combining CEA and CA125 with autoantibodies detection

Objectives: Although low-dose computed tomography has been confirmed to have meaningful diagnostic utility, lung cancer is still the leading cause of cancer-related deaths for both genders worldwide. Thus, a novel panel with a stronger diagnostic performance for lung cancer is needed. This study aimed to investigate the efficacy of a new panel in lung cancer diagnosis.

Materials and Methods: The serum levels of carcinoembryonic antigen (CEA), cancer antigen 125 (CA125) and seven autoantibodies were measured and statistically analyzed in samples from healthy controls and patients with lung cancer. The 316 candidates enrolled in this study were randomly assigned into two groups for the training and validation of a diagnostic panel.

Results: An optimal panel with four biomarkers (CEA, CA125, Annexin A1-Ab, and Alpha enolase-Ab) was established, with an area under the receiver operator characteristic (ROC) curve (AUC) of 0.897, a sensitivity of 86.5%, a specificity of 82.3%, a positive predictive value (PPV) of 88.3%, a negative predictive value (NPV) of 79.7%, and a diagnostic accuracy of 84.8% for the training group. The panel was validated, with an AUC of 0.856 and a sensitivity of 87.5% for the validation group. Furthermore, the new panel performed significantly better in lung cancer screening than did CEA and CA125 in all of the cohorts (p< .05).

Conclusion: The diagnostic performance of CEA and CA125 was significantly enhanced through their combination with two autoantibodies (Annexin A1-Ab, and Alpha enolase-Ab). Optimization of the measured autoantibodies is critical for generating a panel to detect lung cancer in patients.

Serum anti-GAPDH autoantibody levels reflect the severity of cervical lesions: A potential serum biomarker for cervical cancer screening

Recent studies have indicated that a certain level of autoantibodies may be essential for maintaining good health as well as preventing cancer development, and that the levels of serum autoantibodies can decline during malignant progression. The aim of the present study was to identify such an autoantibody-based biomarker for screening cervical lesions. An autoantigen reactive with healthy female sera was detected in the cytosolic fraction of HeLa cells, a cervical cancer cell line, and identified. Serum immunoglobulin (Ig)-G and IgM levels against the purified autoantigen in normal, cervical intraepithelial neoplasias (CINs) I, II and III, and cervical cancer were compared using ELISAs. The autoantigen in HeLa cells was identified to be GAPDH. The serum levels of anti-HeLa-GAPDH IgG decreased with increasing severity of cervical lesions, and similar decreases in IgM levels were revealed. Notably, the anti-HeLa-GAPDH IgG level was discovered to discriminate cervical cancer from normal samples with 80.0% sensitivity and 96.6% specificity. The serum anti-HeLa-GAPDH autoantibody level, as a single parameter, is a promising serum biomarker for screening cervical lesions.

Anti α-enolase antibody is a novel autoimmune biomarker for unexplained recurrent miscarriages

Background

We recently demonstrated the increased abundance of anti-trophoblast antibodies (ATAB) in sera of patients with unexplained recurrent miscarriages (uRM). Further, the ATAB-positive sera bound to JEG-3 human choriocarcinoma cells in vitro, resulting in decreased productions of β-human chorionic gonadotropin (β-hCG) and progesterone in these cells. However, the specific antigenic epitopes of ATAB have remained unknown. Therefore, it was the aim of this study to determine specific targets of ATAB in uRM patients.

Methods

Potential targets of ATAB were analyzed by 2-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry, and thereby identifying α-Enolase (ENO1). ATAB targeting of ENO1 was further confirmed in a competitive binding assay. Levels of anti-ENO1 antibodies as well as β-hCG and progesterone were quantified with enzyme-linked immunosorbent assay (ELISA). Additionally, expression of ENO1 was analyzed in first trimester placentas by immunohistochemistry and immunofluorescence analysis.

Findings

We here identified ENO1 as a prominent target of ATAB. Serum levels of anti-ENO1 antibodies were increased in ATAB-positive compared to ATAB-negative patients. Further, increased expression of ENO1 and its co-expression with β-arrestin was found in the extra villous trophoblasts of uRM patients in first trimester placentas. In vitro, anti-ENO1 antibodies decreased the secretion of β-hCG and progesterone in JEG-3 and primary human villous trophoblast cells.

Interpretation

Serum anti-ENO1 antibodies might be an autoimmune biomarker for uRM. Targeting the formation of anti-ENO1 antibodies or inhibition of ENO1 expression could potentially represent therapeutic strategies for these patients.

Fund

All authors declare no conflict of interest. Yao Ye was supported by the China Scholarship Council. Hellen Ishikawa-Ankerhold and Christian Schulz were supported by the SFB914, projects Z01 and A10. None of the rest authors has any conflict of interest to declare.

Diagnostic value of α-enolase expression and serum α-enolase autoantibody levels in lung cancer

OBJECTIVE

To investigate the diagnostic value of α-enolase (ENO1) and serum ENO1 autoantibody levels in lung cancer.

METHODS

Immunohistochemistry staining and ELISA were performed to detect ENO1 expression in lung tissue and serum ENO1 autoantibody levels, respectively.

RESULTS

The expression of ENO1 was higher in lung cancer tissues than in benign lung disease tissues (p < 0.001). The proportion of lung cancer samples expressing ENO1 was not significantly different among the various pathological classification groups. The proportion of samples expressing ENO1 was higher in lung cancer patients in stages I/II than in those in stages III/IV (χ2 = 5.445; p = 0.018). The expression of ENO1 in lung cancer tissues was not associated with age, gender, or smoking history. Serum ENO1 antibody levels were significantly higher in the lung cancer group than in the benign lung disease and control groups (p < 0.001). The differences among the pathological classification groups were not statistically significant. Serum ENO1 antibody levels were also in lung cancer patients in stages I/II than in those in stages III/IV (p < 0.01). Serum ENO1 antibody levels were not associated with age, gender, or smoking history in lung cancer patients. The ROC curve representing the diagnosis of lung cancer based on ENO1 antibody levels had an area under the curve of 0.806.

CONCLUSIONS

Our results suggest that high levels of ENO1 are associated with the clinical stage of lung cancer and that ENO1 expression and its serum autoantibody levels show diagnostic value in lung cancer.

Alpha-enolase promotes gastric cancer cell proliferation and metastasis via regulating AKT signaling pathway

Increased aerobic glycolysis is considered as a hallmark of cancer and targeting key glycolytic enzymes will be a promising therapeutic approach in cancer treatment. Alpha-enolase (ENO1), as a prominent glycolytic enzyme, is upregulated in multiple cancers and its overexpression is involved in tumor cell proliferation and metastasis. In the present study, we aimed to investigate the potential role of ENO1 in the development and progression of gastric cancer (GC). Here, we found that ENO1 expression was upregulated in human GC and was associated with Lauren type, lymph node metastasis (LNM) and TNM stage. Knockdown of ENO1 attenuated GC cell proliferation and metastasis and reversed epithelial-mesenchymal transition (EMT) progress in vitro while ENO1 overexpression did the opposite. ENO1 could modulate AKT signaling pathway in GC cells and the enhanced proliferation and migration ability induced by ENO1 overexpression was impaired after incubation with PI3K inhibitor Ly294002 in SGC7901 cells. Our data demonstrated that ENO1 enhances GC cell proliferation and metastasis through the protein kinase B (AKT) signaling pathway, indicating that ENO1/AKT signaling axis may serve as a potential target for treatment of GC.

Autoantibodies as Potential Biomarkers in Breast Cancer

Breast cancer is a major cause of mortality in women; however, technologies for early stage screening and diagnosis (e.g., mammography and other imaging technologies) are not optimal for the accurate detection of cancer. This creates demand for a more effective diagnostic means to replace or be complementary to existing technologies for early discovery of breast cancer. Cancer neoantigens could reflect tumorigenesis, but they are hardly detectable at the early stage. Autoantibodies, however, are biologically amplified and hence may be measurable early on, making them promising biomarkers to discriminate breast cancer from healthy tissue accurately. In this review, we summarized the recent findings of breast cancer specific antigens and autoantibodies, which may be useful in early detection, disease stratification, and monitoring of treatment responses of breast cancer.

Comparative two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) of human milk to identify dysregulated proteins in breast cancer

Breast cancer (BC) remains a major cause of mortality, and early detection is considered important for reducing BC-associated deaths. Early detection of BC is challenging in young women, due to the limitations of mammography on the dense breast tissue of young women. We recently reported results of a pilot proteomics study, using one-dimensional polyacrylamide gel electrophoresis (1D-PAGE) and mass spectrometry (MS) to investigate differences in milk proteins from women with and without BC. Here, we applied two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and MS to compare the protein pattern in milk from the breasts of a single woman who was diagnosed with BC in one breast 24 months after donating her milk. Statistically different gel spots were picked for protein digestion followed by nanoliquid chromatography tandem MS (nanoLC-MS/MS) analysis. The upregulated proteins in BC versus control are alpha-amylase, gelsolin isoform a precursor, alpha-2-glycoprotein 1 zinc isoform CRA_b partial, apoptosis-inducing factor 2 and vitronectin. Several proteins were downregulated in the milk of the breast later diagnosed with cancer as compared to the milk from the healthy breast, including different isoforms of albumin, cholesterol esterase, different isoforms of lactoferrin, different proteins from the casein family and different isoforms of lysozyme. Results warrant further studies to determine the usefulness of these milk proteins for assessing risk and detecting occult disease. MS data is available via ProteomeXchange with identifier PXD009860.

Next Generation Immunotherapy for Pancreatic Cancer: DNA Vaccination is Seeking New Combo Partners

Pancreatic Ductal Adenocarcinoma (PDA) is an almost incurable radio- and chemo-resistant tumor, and its microenvironment is characterized by a strong desmoplastic reaction associated with a significant infiltration of T regulatory lymphocytes and myeloid-derived suppressor cells (Tregs, MDSC). Investigating immunological targets has identified a number of metabolic and cytoskeletal related molecules, which are typically recognized by circulating antibodies. Among these molecules we have investigated alpha-enolase (ENO1), a glycolytic enzyme that also acts a plasminogen receptor. ENO1 is also recognized by T cells in PDA patients, so we developed a DNA vaccine that targets ENO1. This efficiently induces many immunological processes (antibody formation and complement-dependent cytotoxicity (CDC)-mediated tumor killing, infiltration of effector T cells, reduction of infiltration of myeloid and Treg suppressor cells), which significantly increase the survival of genetically engineered mice that spontaneously develop pancreatic cancer. Although promising, the ENO1 DNA vaccine does not completely eradicate the tumor, which, after an initial growth inhibition, returns to proliferate again, especially when Tregs and MDSC ensue in the tumor mass. This led us to develop possible strategies for combinatorial treatments aimed to broaden and sustain the antitumor immune response elicited by DNA vaccination. Based on the data we have obtained in recent years, this review will discuss the biological bases of possible combinatorial treatments (chemotherapy, PI3K inhibitors, tumor-associated macrophages, ENO1 inhibitors) that could be effective in amplifying the response induced by the immune vaccination in PDA.

Use of autoantibodies against tumor-associated antigens as serum biomarkers for primary screening of cervical cancer

Serum autoantibodies against tumor-associated antigens (TAAs) have received much attention as potential biomarkers for early detection of cancers, since they can be detected in the early stages of cancers. Autoantibodies against Cancer Antigen 15-3 (CA15-3), carcinoembryonic antigen (CEA), Cancer Antigen 19-9 (CA19-9), c-Myc, p53, heat shock protein (Hsp)27 and Hsp70 have been suggested as potential markers for detecting several types of cancer. In the present study, the seven types of antibody listed above were evaluated for detecting cervical lesions. Enzyme-linked immunosorbent assays (ELISAs) were used to measure IgG levels of the autoantibodies in women with normal cytology, cervical intraepithelial neoplasia (CIN) I, CIN II, CIN III and cervical cancer. The increases of anti-CA15-3 and anti-CEA IgG in cervical cancer were more pronounced than the increases of the other markers, and the level of anti-CA19-9 IgG in CIN III stage was higher than in normal CIN I, CIN II or cervical cancer. A combination of ELISAs detecting anti-CA15-3, anti-CEA and anti-CA19-9 IgGs was found to reliably discriminate CINs from normal and to strongly differentiate cancer from normal (90.3% of sensitivity and 82.1% of specificity). We suggest that the combination of three ELISA may be useful for detecting cervical lesions.

Epsilon-aminocaproic acid prevents high glucose and insulin induced-invasiveness in MDA-MB-231 breast cancer cells, modulating the plasminogen activator system

Obesity and type II diabetes mellitus have contributed to the increase of breast cancer incidence worldwide. High glucose concentration promotes the proliferation of metastatic cells, favoring the activation of the plasminogen/plasmin system, thus contributing to tumor progression. The efficient formation of plasmin is dependent on the binding of plasminogen to the cell surface. We studied the effect of ε-aminocaproic acid (EACA), an inhibitor of the binding of plasminogen to cell surface, on proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and plasminogen activation system, in metastatic MDA-MB-231 breast cancer cells grown in a high glucose microenvironment and treated with insulin. MDA-MB-231 cells were treated with EACA 12.5 mmol/L under high glucose 30 mmol/L (HG) and high glucose and insulin 80 nmol/L (HG-I) conditions, evaluating: cell population growth, % of viability, migratory, and invasive abilities, as well as the expression of uPA, its receptor (uPAR), and its inhibitor (PAI-1), by real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, MMP-2 and MMP-9 mRNAs were evaluated by RT-PCR. Markers of EMT were evaluated by Western blot. Additionally, the presence of active uPA was studied by gel zymography, using casein-plasminogen as substrates. EACA prevented the increase in cell population, migration and invasion induced by HG and insulin, which was associated with the inhibition of EMT and the attenuation of HG- and insulin-dependent expression of uPA, uPAR, PAI-1, MMP-2, MMP-9, α-enolase (ENO A), and HCAM. The interaction of plasminogen to the cell surface and plasmin formation are mediators of the prometastasic action of hyperglycemia and insulin, potentially, EACA can be employed in the prevention and as adjuvant treatment of breast tumorigenesis promoted by hyperglycemia and insulin.

Serological proteome analysis approach-based identification of ENO1 as a tumor-associated antigen and its autoantibody could enhance the sensitivity of CEA and CYFRA 21-1 in the detection of non-small cell lung cancer

PURPOSE

Lung cancer (LC) is the leading cause of cancer-related deaths for both male and female worldwide. Early detection of LC could improve five-year survival rate up to 48.8% compared to 3.3% of late/distant stage. Autoantibodies to tumor-associated antigens (TAAs) have been described as being present before clinical symptoms in lung and other cancers. We aimed to identify more TAAs to improve the performance for discovering non-small cell lung cancer (NSCLC) patients from healthy individuals.

METHODS

Two independent sets were included in this study. Serological proteome analysis (SERPA) was used to identify TAAs from NSCLC cell line H1299 in a discovery set. In validation study, anti-ENO1 autoantibody was examined by immunoassay in sera from 242 patients with NSCLC and 270 normal individuals.

RESULTS

A 47 KDa protein was identified to be alpha-enolase (ENO1) by using SERPA. Analysis of sera from 512 participants by ELISA showed significantly higher frequency of anti-ENO1 autoantibodies in NSCLC sera compared with the sera from normal individuals, with AUC (95%CI) of 0.589 (0.539-0.638, P=0.001). There was no significant difference in frequency of anti-ENO1 in different stages, histological or metastasis status of NSCLC. When anti-ENO1 detection was combined with other two tumor protein biomarkers (CEA and CYFRA 21-1), the sensitivity of NSCLC increased to 84%.

CONCLUSIONS

ENO1 can elicit humoral immune response in NSCLC and its autoantibody has association with the tumorigenesis of NSCLC. Furthermore, these intriguing results suggest the possibility of autoantibody against ENO1 serving as a potential diagnostic biomarker in NSCLC and have implications for defining novel histological determinants of NSCLC.

Targeting Enolase in Reducing Secondary Damage in Acute Spinal Cord Injury in Rats

Spinal cord injury (SCI) is a complex debilitating condition leading to permanent life-long neurological deficits. The complexity of SCI suggests that a concerted multi-targeted therapeutic approach is warranted to optimally improve function. Damage to spinal cord is complicated by an increased detrimental response from secondary injury factors mediated by activated glial cells and infiltrating macrophages. While elevation of enolase especially neuron specific enolase (NSE) in glial and neuronal cells is believed to trigger inflammatory cascades in acute SCI, alteration of NSE and its subsequent effects in acute SCI remains unknown. This study measured NSE expression levels and key inflammatory mediators after acute SCI and investigated the role of ENOblock, a novel small molecule inhibitor of enolase, in a male Sprague-Dawley (SD) rat SCI model. Serum NSE levels as well as cytokines/chemokines and metabolic factors were evaluated in injured animals following treatment with vehicle alone or ENOblock using Discovery assay. Spinal cord samples were also analyzed for NSE and MMPs 2 and 9 as well as glial markers by Western blotting. The results indicated a significant decrease in serum inflammatory cytokines/chemokines and NSE, alterations of metabolic factors and expression of MMPs in spinal cord tissues after treatment with ENOblock (100 µg/kg, twice). These results support the hypothesis that activation of glial cells and inflammation status can be modulated by regulation of NSE expression and activity. Analysis of SCI tissue samples by immunohistochemistry confirmed that ENOblock decreased gliosis which may have occurred through reduction of elevated NSE in rats. Overall, elevation of NSE is deleterious as it promotes extracellular degradation and production of inflammatory cytokines/chemokines and metabolic factors which activates glia and damages neurons. Thus, reduction of NSE by ENOblock may have potential therapeutic implications in acute SCI.

α-enolase promotes tumorigenesis and metastasis via regulating AMPK/mTOR pathway in colorectal cancer

The α-enolase (ENO1) plays pivotal roles in several types of cancer, but its clinical significance, functional role, and possible mechanism in colorectal cancer (CRC) have remained unclear. Expression level of ENO1 in CRC tissues was examined by qRT-PCR, Western blot, and immunohistochemistry. The effects of ENO1 on cell growth were investigated by MTT, colony formation, flow cytometry assays, and in vivo tumorigenic capacity analysis. The impacts of ENO1 on cell migration and invasion were also explored by scratch-healing, Transwell or Matrigel chamber assays, and in vivo metastatic capacity analysis. Our results showed that the expression level of ENO1 was significantly elevated in CRC tissues. High expression level of ENO1 was associated with disease progression in CRC patients. Overexpression of ENO1 in HCT116 cell line promoted cell proliferation, migration, and invasion in vitro as well as tumorigenesis and metastasis in vivo. In other hand, ablation of ENO1 in HCT116 cells led to totally reverse effects. Mechanistically, we revealed ENO1 could regulate AMPK/mTOR signaling pathway. AMPK pathway activation or mTOR pathway suppression blocked these ENO1 induced alterations. Together, our results demonstrated that ENO1 is a potent promoter of CRC genesis and metastasis at least in part though regulating AMPK/mTOR pathway. These findings also suggested that ENO1 may be a promising therapeutic target in CRC patients.

Paraneoplastic neurological complications of breast cancer

Breast cancer is the most frequent cause of cancer of women in much of the world. In countries with screening programs, breast cancer is often detected before clinical symptoms are apparent, but occasionally the occurrence of a paraneoplastic syndrome precedes the identification of cancer. In breast cancer, there are known to be paraneoplastic endocrine syndromes and neurologic syndromes. The neurologic syndromes are often hard to identify and treat. The neurologic syndromes associated with breast cancer include cerebellar degeneration, sensorimotor neuropathy, retinopathy, stiff-persons syndrome, encephalitis, and opsoclonus-myoclonus. Most of these are mediated by antibodies against known neural antigens, although some cases appear to be mediated by non-humoral mechanisms. Treatments differ depending upon the syndrome type and etiology. Outcomes also vary depending upon duration of disease, the treatments used and the responsiveness of the underlying cancer. A thorough review of the published literature is provided along with recommendations for management and future research.

Anti-α-enolase is a prognostic marker in postoperative lung cancer patients

Our previous studies suggest that antibodies against ENO1 (anti-ENO1 Ab) have a protective role in patients with non-small cell lung carcinoma. In this study, we evaluated the prognostic value of anti-ENO1 Ab levels in non-small cell lung carcinoma patients undergoing surgery. Circulating levels of anti-ENO1 Ab were assessed in 85 non-small cell lung carcinoma patients before and after surgery, and were correlated with clinical outcome. After surgery, patients with a higher increase of anti-ENO1 Ab had a lower hazard ratio and a better progression-free survival. Using animal models, we demonstrated that tumor cells reduce the circulating levels of anti-ENO1 Ab through physical absorption and neutralization of anti-ENO1 Ab with surface-expressed and secreted ENO1, respectively. Mice transplanted with ENO1-overexpressing tumors generated ENO1-specific regulatory T cells to suppress the production of anti-ENO1 Ab. Our results suggest that the increase of anti-ENO1 Ab may reflect anti-tumor immune responses and serve as a prognostic marker in postoperative lung cancer patients.

Neuron specific enolase: a promising therapeutic target in acute spinal cord injury

Enolase is a multifunctional protein, which is expressed abundantly in the cytosol. Upon stimulatory signals, enolase can traffic to cell surface and contribute to different pathologies including injury, autoimmunity, infection, inflammation, and cancer. Cell-surface expression of enolase is often detected on activated macrophages, microglia/macrophages, microglia, and astrocytes, promoting extracellular matrix degradation, production of pro-inflammatory cytokines/chemokines, and invasion of inflammatory cells in the sites of injury and inflammation. Inflammatory stimulation also induces translocation of enolase from the cytosolic pool to the cell surface where it can act as a plasminogen receptor and promote extracellular matrix degradation and tissue damage. Spinal cord injury (SCI) is a devastating debilitating condition characterized by progressive pathological changes including complex and evolving molecular cascades, and insights into the role of enolase in multiple inflammatory events have not yet been fully elucidated. Neuronal damage following SCI is associated with an elevation of neuron specific enolase (NSE), which is also known to play a role in the pathogenesis of hypoxic-ischemic brain injury. Thus, NSE is now considered as a biomarker in ischemic brain damage, and it has recently been suggested to be a biomarker in traumatic brain injury (TBI), stroke and anoxic encephalopathy after cardiac arrest and acute SCI as well. This review article gives an overview of the current basic research and clinical studies on the role of multifunctional enolase in neurotrauma, with a special emphasis on NSE in acute SCI.

Tumour-Associated Autoantibodies as Diagnostic Biomarkers for Breast Cancer: A Systematic Review and Meta-Analysis

Tumour-associated autoantibodies may be promising biomarkers that could facilitate breast cancer (BC) diagnosis and improve patient outcomes. This review aims to identify the tumour-associated autoantibodies with the greatest diagnostic potential. Systematic searches were conducted using PubMed and Web of Science. The most studied tumour-associated autoantibody was included in a meta-analysis, and its clinical value was determined using Fagan's nomogram. The analysis included 84 studies regarding tumour-associated autoantibodies with the diagnostic value. Anti-p53 antibody was the most frequently studied autoantibody, followed by autoantibodies against MUC1, HER2 and cyclin B1. Although individual tumour-associated autoantibodies showed low diagnostic sensitivity, combinations of autoantibodies offered relatively high sensitivity. Enzyme-linked immunosorbent assay (ELISA) was the most common detection method, and nucleic acid programmable protein microarrays appeared preferable to common protein microarrays. As the most commonly studied autoantibody, anti-p53 antibody was included in a meta-analysis. When it had been detected using ELISA and cut-off values were defined as the mean +2 or 3 standard deviations, the summary area under the receiver operating characteristic curve for the presence of BC was 0.78. Fagan's nomogram showed post-test probabilities of 32% and 6% for positive and negative results, respectively. Mammography might be supplemented by the use of tumour-associated autoantibodies as biomarkers for BC diagnosis in younger women with increased risks of BC. Even though several studies have investigated the diagnostic use of tumour-associated autoantibodies as biomarkers for BC detection, a high-quality prospective study is needed to validate their diagnostic value in practice.

Latest updates on antiretinal autoantibodies associated with vision loss and breast cancer

Cancer-associated retinopathy (CAR) is an uncommon paraneoplastic disorder of the retina that is frequently associated with breast cancer in pre- and postmenopausal women older than 50 years. In this review, we will give an update on the current knowledge regarding the association of antiretinal autoantibodies with the breast-CAR syndrome. Women with breast cancer and visual indications of CAR have a significantly increased incidence of autoantibodies (AAbs) against retinal proteins when compared to healthy women. The onset of visual loss in association with antiretinal AAbs peaks 2 to 3 years after the clinical diagnosis of breast cancer. Differences in severity of symptoms between women with or without antiretinal AAbs are evident, revealing more unfavorable presentation in seropositive women. The incidence of CAR in breast cancer is likely to rise as the survival time of patients with breast cancer increases; consequently, a prediction of breast-CAR based on autoimmunity to individual retinal antigens, or to panels of antigens (signatures), is clinically important.

Identification of ENO1 as a potential sputum biomarker for early-stage lung cancer by shotgun proteomics

BACKGROUND

Lung cancer is the leading cancer killer. Early detection will reduce the related deaths. The objective of this study was to identify potential biomarkers for early-stage lung cancer in sputum supernatant.

MATERIALS AND METHODS

Using shotgun proteomics, we detected changes in protein profiles that were associated with lung cancer by analyzing sputum supernatants from 6 patients with early-stage lung cancer and 5 cancer-free controls. Using western blotting, we validated the proteomic results in 22 lung cancer cases and 22 controls. Using enzyme-linked immunosorbent assay (ELISA), we evaluated the diagnostic performance of the biomarker candidates in an independent set of 35 cases and 36 controls.

RESULTS

Proteomics identified 8 biomarker candidates for lung cancer. Western blotting validation of the candidates showed that enolase 1 (ENO1) displayed a higher expression level in patients with cancer than in cancer-free individuals (P = .015). ELISA revealed that the assessment of ENO1 expression in sputum supernatant had 58.33% sensitivity and 80.00% specificity in distinguishing patients with stage I lung cancer from cancer-free individuals.

CONCLUSION

The analysis of protein biomarkers in sputum may provide a potential approach for the early detection of lung cancer. Future validation of all the candidates defined by shotgun proteomics in a large cohort study may help develop additional biomarkers that can be added to ENO1 to provide more diagnostic efficacy for lung cancer.

Surface α-enolase promotes extracellular matrix degradation and tumor metastasis and represents a new therapeutic target

In previous research, we found α-enolase to be inversely correlated with progression-free and overall survival in lung cancer patients and detected α-enolase on the surface of lung cancer cells. Based on these findings, we hypothesized that surface α-enolase has a significant role in cancer metastasis and tested this hypothesis in the current study. We found that α-enolase was co-immunoprecipitated with urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen in lung cancer cells and interacted with these proteins in a cell-free dot blotting assay, which can be interrupted by α-enolase-specific antibody. α-Enolase in lung cancer cells co-localized with these proteins and was present at the site of pericellular degradation of extracellular matrix components. Treatment with antibody against α-enolase in vitro suppressed cell-associated plasminogen and matrix metalloproteinase activation, collagen and gelatin degradation, and cell invasion. Examination of the effect of treatment with shRNA plasmids revealed that down regulation of α-enolase decreases extracellular matrix degradation by and the invasion capacity of lung cancer cells. Adoptive transfer of α-enolase-specific antibody to mice resulted in accumulation of antibody in subcutaneous tumor and inhibited the formation of tumor metastasis in lung and bone. This study demonstrated that surface α-enolase promotes extracellular matrix degradation and invasion of cancer cells and that targeting surface α-enolase is a promising approach to suppress tumor metastasis.

Three are better than one: plasminogen receptors as cancer theranostic targets

Activation of plasminogen on the cell surface initiates a cascade of protease activity with important implications for several physiological and pathological events. In particular, components of the plasminogen system participate in tumor growth, invasion and metastasis. Plasminogen receptors are in fact expressed on the cell surface of most tumors, and their expression frequently correlates with cancer diagnosis, survival and prognosis. Notably, they can trigger multiple specific immune responses in cancer patients, highlighting their role as tumor-associated antigens. In this review, three of the most characterized plasminogen receptors involved in tumorigenesis, namely Annexin 2 (ANX2), Cytokeratin 8 (CK8) and alpha-Enolase (ENOA), are analyzed to ascertain an overall view of their role in the most common cancers. This analysis emphasizes the possibility of delineating new personalized therapeutic strategies to counteract tumor growth and metastasis by targeting plasminogen receptors, as well as their potential application as cancer predictors.

Identification and validation of new autoantibodies for the diagnosis of DCIS and node negative early-stage breast cancers

Evidence of circulating autoantibodies in cancer patient sera has created opportunities for exploiting them as biomarkers. We report the identification and the clinical validation of an autoantibody panel in newly diagnosed patients with early-stage breast cancer. Proteomic approach and serological screening of a discovery set of sera (n = 80) were performed to identify tumor-associated antigens (TAAs). Autoantibody levels were then measured in an independent validation set (n = 182) against a panel of five TAAs by enzyme-linked immunosorbent assay. Sixty-seven antigens that elicited a specific humoral response in breast cancer were identified and five antigens (GAL3, PAK2, PHB2, RACK1 and RUVBL1) were selected for validation. GAL3 and RACK1 showed significantly increased reactivity in early-stage breast cancer. When combined, the five markers significantly discriminated early-stage cancer from healthy individuals (AUC = 0.81; 95% CI [0.74-0.86]). Interestingly, this value was high in both node-negative early-stage primary breast cancer (AUC = 0.81; 95% CI [0.72-0.88]) and ductal carcinoma in situ (AUC = 0.85; 95% CI [0.76-0.95]) populations. This autoantibody panel could be useful as a diagnostic tool in a screening strategy of early-stage invasive breast cancer and preinvasive breast cancer. It could be particularly appropriate in complement to mammography for women with high breast density.

T cells and adoptive immunotherapy: recent developments and future prospects in gastrointestinal oncology

Gastrointestinal oncology is one of the foremost causes of death: the gastric cancer accounts for 10.4% of cancer deaths worldwide, the pancreatic cancer for 6%, and finally, the colorectal cancer for 9% of all cancer-related deaths. For all these gastrointestinal cancers, surgical tumor resection remains the primary curative treatment, but the overall 5-year survival rate remains poor, ranging between 20-25%; the addition of combined modality strategies (pre- or postoperative chemoradiotherapy or perioperative chemotherapy) results in 5-year survival rates of only 30-35%. Therefore, many investigators believe that the potential for making significant progress lies on understanding and exploiting the molecular biology of gastrointestinal tumors to investigate new therapeutic strategies such as specific immunotherapy. In this paper we will focus on recent knowledge concerning the role of T cells and the use of T adoptive immunotherapy in the treatment of gastrointestinal cancers.

α-Enolase: a promising therapeutic and diagnostic tumor target

α-enolase (ENOA) is a metabolic enzyme involved in the synthesis of pyruvate. It also acts as a plasminogen receptor and thus mediates activation of plasmin and extracellular matrix degradation. In tumor cells, ΕΝΟΑ is upregulated and supports anaerobic proliferation (Warburg effect), it is expressed at the cell surface, where it promotes cancer invasion, and is subjected to a specific array of post-translational modifications, namely acetylation, methylation and phosphorylation. Both ENOA overexpression and its post-translational modifications could be of diagnostic and prognostic value in cancer. This review will discuss recent information on the biochemical, proteomics and immunological characterization of ENOA, particularly its ability to trigger a specific humoral and cellular immune response. In our opinion, this information can pave the way for effective new therapeutic and diagnostic strategies to counteract the growth of the most aggressive human disease.