Prognostic role of serum AZGP1, PEDF and PRDX2 in colorectal cancer patients

Zinc-alpha-2-glycoprotein overexpression and maintaining anti-apoptotic function in oral squamous cell carcinoma

OBJECTIVE

Overexpression of zinc-alpha-2-glycoprotein (ZAG) can be induced by various factors and has potential to be a biomarker in certain malignancies. However, in oral squamous cell carcinoma (OSCC), the risks and effects associated with ZAG overexpression are still poorly known. Here, we investigated the effect of HPV16 oncogenes and arecoline on the expression levels of ZAG and the possible effects of ZAG in OSCC cell lines.

DESIGN

The level of ZAG expression was determined in protein extracted from exfoliated buccal cells from cancer-free control individuals and oral lesion cells from OSCC. Oral cell lines expressing HPV16E6/E7, and treated with arecoline were prepared to investigate ZAG expression. The effects of ZAG on cell biological activity and its targeting of UCP1 were determined in ZAG-overexpressing and ZAG-knockdown cells.

RESULTS

The expression of ZAG protein was significantly increased in oral lesion cells from OSCC relative to controls. Notably, the expression level of ZAG in OSCC positive for HPV, betel-quid chewing, and combination of both factors, was slightly higher than in cancer-free controls. ZAG expression was upregulated in oral cells treated with HPV16 oncoproteins E6 and/or E7, and treatment with arecoline (25 μg/ml). Interestingly, ZAG overexpression significantly increased UCP1 and decreased apoptosis, whereas decreased UCP1 and increased apoptosis were found in ZAG-knockdown cells. The mRNA expression levels of TP53, STAT3, BCL2, and NFKB1 corresponded to observed anti-apoptosis function.

CONCLUSIONS

HPV oncoproteins and high doses of arecoline are risk factors for an overexpressed ZAG protein that has an anti-apoptotic function in OSCC.

Zinc-Alpha-2-Glycoprotein Peptide Downregulates Type I and III Collagen Expression via Suppression of TGF-β and p-Smad 2/3 Pathway in Keloid Fibroblasts and Rat Incisional Model

BACKGROUND

Keloids and hypertrophic scars result from abnormal collagen accumulation and the inhibition of its degradation. Although the pathogenesis remains unclear, excessive accumulation of the extracellular matrix (ECM) is believed to be associated with the TGF-β/SMAD pathway. Zinc-alpha-2-glycoprotein (ZAG) inhibits TGF-β-mediated epithelial-to-mesenchymal transdifferentiation and impacts skin barrier functions. In this study, we investigated the potential of a small ZAG-derived peptide against hypertrophic scars and keloids.

METHODS

The study examined cell proliferation and mRNA expression of collagen types I and III in human dermal fibroblast (HDF) cell lines and keloid-derived fibroblasts (KF) following ZAG peptide treatment. A rat incisional wound model was used to evaluate the effect of ZAG peptide in scar tissue.

RESULTS

Significantly lower mRNA levels of collagen types I and III were observed in ZAG-treated fibroblasts, whereas matrix metalloproteinase (MMP)-1 and MMP-3 mRNA levels were significantly increased in HDFs and KFs. Furthermore, ZAG peptide significantly reduced protein expression of collagen type I and III, TGF-β1, and p-Smad2/3 complex in KFs. Rat incisional scar models treated with ZAG peptide presented narrower scar areas and reduced immature collagen deposition, along with decreased expression of collagen type I, α-SMA, and p-Smad2/3.

CONCLUSION

ZAG peptide effectively suppresses the TGF-β and p-Smad2/3 pathway and inhibits excessive cell proliferation during scar formation, suggesting its potential therapeutic implications against keloids and hypertrophic scars.

Zinc-alpha-2-glycoprotein Secreted by Triple-Negative Breast Cancer Promotes Peritumoral Fibrosis

Obesity is a modifiable predisposition factor for postmenopausal breast cancer. This suggests a localized, reciprocal interaction between breast cancer cells and the surrounding mammary white adipose tissue. To investigate how breast cancer cells alter the composition and function of adipose tissue, we screened the secretomes of 10 human breast cancer cell lines for the ability to modulate the differentiation of adipocyte stem and progenitor cells. The screen identified an adipogenic modulator, zinc-alpha-2-glycoprotein (ZAG/AZGP1) that is secreted by triple-negative breast cancer (TNBC) cells. TNBC-secreted ZAG inhibits adipogenesis and instead induces the expression of fibrotic genes. Accordingly, depletion of ZAG in TNBC cells attenuates fibrosis in white adipose tissue and inhibits tumor growth. Further, high expression of ZAG is linked to poor prognosis in patients with TNBC but not in patients with other clinical subtypes of breast cancer. Our findings suggest a role of TNBC-secreted ZAG in promoting the transdifferentiation of adipocyte stem and progenitor cells into cancer-associated fibroblasts to support tumorigenesis.

SIGNIFICANCE

Functional screening of breast cancer secretomes revealed that triple-negative breast cancer promotes fibrosis in the adipose tissue microenvironment by secreting zinc-alpha-2-glycoprotein and promoting the transdifferentiation of adipocyte stem cells into myofibroblasts.

Mass Spectrometry Proteomics Characterization of Plasma Biomarkers for Colorectal Cancer Associated With Inflammation

Background

Colorectal cancer (CRC) prognosis is determined by the disease stage with low survival rates for advanced stages. Current CRC screening programs are mainly using colonoscopy, limited by its invasiveness and high cost. Therefore, non-invasive, cost-effective, and accurate alternatives are urgently needed.

Objective and design

This retrospective multi-center plasma proteomics study was performed to identify potential blood-based biomarkers in 36 CRC patients and 26 healthy volunteers by high-resolution mass spectrometry proteomics followed by the validation in an independent CRC cohort (60 CRC patients and 44 healthy subjects) of identified selected biomarkers.

Results

Among the 322 identified plasma proteins, 37 were changed between CRC patients and healthy volunteers and were associated with the complement cascade, cholesterol metabolism, and SERPIN family members. Increased levels in CRC patients of the complement proteins C1QB, C4B, and C5 as well as pro-inflammatory proteins, lipopolysaccharide-binding protein (LBP) and serum amyloid A4, constitutive (SAA4) were revealed for first time. Importantly, increased level of C5 was verified in an independent validation CRC cohort. Increased C4B and C8A levels were correlated with cancer-associated inflammation and CRC progression, while cancer-associated inflammation was linked to the acute-phase reactant leucine-rich alpha-2-glycoprotein 1 (LRG1) and ceruloplasmin. Moreover, a 4-protein signature including C4B, C8A, apolipoprotein C2 (APO) C2, and immunoglobulin heavy constant gamma 2 was changed between early and late CRC stages.

Conclusion

Our results suggest that C5 could be a potential biomarker for CRC diagnosis. Further validation studies will aid the application of these new potential biomarkers to improve CRC diagnosis and patient care.

Expression and significance of pigment epithelium-derived factor and vascular endothelial growth factor in colorectal adenoma and cancer

BACKGROUND

The incidence and mortality of colorectal cancer (CRC) are among the highest in the world, and its occurrence and development are closely related to tumor neovascularization. When the balance between pigment epithelium-derived factors (PEDF) that inhibit angiogenesis and vascular endothelial growth factors (VEGF) that stimulate angiogenesis is broken, angiogenesis is out of control, resulting in tumor development. Therefore, it is very necessary to find more therapeutic targets for CRC for early intervention and later treatment.

AIM

To investigate the expression and significance of PEDF, VEGF, and CD31-stained microvessel density values (CD31-MVD) in normal colorectal mucosa, adenoma, and CRC.

METHODS

In this case-control study, we collected archived wax blocks of specimens from the Digestive Endoscopy Center and the General Surgery Department of Chengdu Second People's Hospital from April 2022 to October 2022. Fifty cases of specimen wax blocks were selected as normal intestinal mucosa confirmed by electronic colonoscopy and concurrent biopsy (normal control group), 50 cases of specimen wax blocks were selected as colorectal adenoma confirmed by electronic colonoscopy and pathological biopsy (adenoma group), and 50 cases of specimen wax blocks were selected as CRC confirmed by postoperative pathological biopsy after inpatient operation of general surgery (CRC group). An immunohistochemical staining experiment was carried out to detect PEDF and VEGF expression in three groups of specimens, analyze their differences, study the relationship between the two and clinicopathological factors in CRC group, record CD31-MVD in the three groups, and analyze the correlation of PEDF, VEGF, and CD31-MVD in the colorectal adenoma group and the CRC group. The F test or adjusted F test is used to analyze measurement data statistically. Kruskal-Wallis rank sum test was used between groups for ranked data. The chi-square test, adjusted chi-square test, or Fisher's exact test were used to compare the rates between groups. All differences between groups were compared using the Bonferroni method for multiple comparisons. Spearman correlation analysis was used to test the correlation of the data. The test level (α) was 0.05, and a two-sided P< 0.05 was considered statistically significant.

RESULTS

The positive expression rate and expression intensity of PEDF were gradually decreased in the normal control group, adenoma group, and CRC group (100% vs 78% vs 50%, χ2 = 34.430, P < 0.001; ++~++ vs +~++ vs -~+, H = 94.059, P < 0.001), while VEGF increased gradually (0% vs 68% vs 96%, χ2 = 98.35, P < 0.001; - vs -~+ vs ++~+++, H = 107.734, P < 0.001). In the CRC group, the positive expression rate of PEDF decreased with the increase of differentiation degree, invasion depth, lymph node metastasis, distant metastasis, and TNM stage (χ2 = 20.513, 4.160, 5.128, 6.349, 5.128, P < 0.05); the high expression rate of VEGF was the opposite (χ2 = 10.317, 13.134, 17.643, 21.844, 17.643, P < 0.05). In the colorectal adenoma group, the expression intensity of PEDF correlated negatively with CD31-MVD (r = -0.601, P < 0.001), whereas VEGF was not significantly different (r = 0.258, P = 0.07). In the CRC group, the expression intensity of PEDF correlated negatively with the expression intensity of CD31-MVD and VEGF (r = -0.297, P < 0.05; r = -0.548, P < 0.05), while VEGF expression intensity was positively related to CD31-MVD (r = 0.421, P = 0.002).

CONCLUSION

It is possible that PEDF can be used as a new treatment and prevention target for CRC by upregulating the expression of PEDF while inhibiting the expression of VEGF.

Zinc Alpha-2-Glycoprotein (ZAG/AZGP1) secreted by triple-negative breast cancer promotes tumor microenvironment fibrosis

Obesity is a predisposition factor for breast cancer, suggesting a localized, reciprocal interaction between breast cancer cells and the surrounding mammary white adipose tissue. To investigate how breast cancer cells alter the composition and function of adipose tissue, we screened the secretomes of ten human breast cancer cell lines for the ability to modulate the differentiation of adipocyte stem and progenitor cells (ASPC). The screen identified a key adipogenic modulator, Zinc Alpha-2-Glycoprotein (ZAG/AZGP1), secreted by triple-negative breast cancer (TNBC) cells. TNBC-secreted ZAG inhibits adipogenesis and instead induces the expression of fibrotic genes. Accordingly, depletion of ZAG in TNBC cells attenuates fibrosis in white adipose tissue and inhibits tumor growth. Further, high expression of ZAG in TNBC patients, but not other clinical subtypes of breast cancer, is linked to poor prognosis. Our findings suggest a role of TNBC-secreted ZAG in promoting the transdifferentiation of ASPCs into cancer-associated fibroblasts to support tumorigenesis.

AZGP1 activation by lenvatinib suppresses intrahepatic cholangiocarcinoma epithelial-mesenchymal transition through the TGF-β1/Smad3 pathway

Intrahepatic cholangiocarcinoma (ICC) is a primary liver malignancy and is characterized by highly aggressive and malignant biological behavior. Currently, effective treatment strategies are limited. The effect of lenvatinib on ICC is unknown. In this study, we found that AZGP1 was the key target of lenvatinib in ICC, and its low expression in ICC cancer tissues was associated with a poor prognosis in patients. Lenvatinib is a novel AZGP1 agonist candidate for ICC that inhibits ICC-EMT by regulating the TGF-β1/Smad3 signaling pathway in an AZGP1-dependent manner. Furthermore, we found that lenvatinib could increase AZGP1 expression by increasing the acetylation level of H3K27Ac in the promoter region of the AZGP1 gene, thereby inhibiting EMT in ICC cells. In conclusion, lenvatinib activates AZGP1 by increasing the acetylation level of H3K27Ac on the AZGP1 promoter region and regulates the TGF-β1/Smad3 signaling pathway in an AZGP1-dependent manner to inhibit ICC-EMT. This study offers new insight into the mechanism of lenvatinib in the treatment of ICC and provides a theoretical basis for new treatment methods.

The Role of Selected Serpins in Gastrointestinal (GI) Malignancies

Gastrointestinal (GI) cancers, which are a diverse group of malignant diseases, represent a major healthcare problem around the world. Due to the lack of specific symptoms in the early stages as well as insufficient diagnostic possibilities, these malignancies occupy the leading position in the causes of death worldwide. The currently available tests have too many limitations to be part of routine diagnostics. Therefore, new potential biomarkers that could be used as diagnostic and prognostic factors for these cancers are still being sought. Among the proteins that might fit this role are serpins, which are serine protease inhibitors. Although the serpins themselves have been known for many years, they have recently become the centre of attention for many authors, especially due to the fact that a number of proteins in this family are involved in many stages of neoplasia formation, from angiogenesis through tumour growth to progression. Therefore, the aim of this review is to present the current knowledge about the significance of serpins in GI malignancies, especially their involvement in the development and progression of oesophageal, gastric, pancreatic and colorectal cancers. This review summarises and confirms the important roles of selected serpins in the pathogenesis of various GI cancers and also points to their promising roles as therapeutic targets. However, due to the relatively nonspecific nature of serpins, future research should be carried out to elucidate the mechanisms involved in tumour pathogenesis in more detail.

The increasing role of pigment epithelium-derived factor in metastasis: from biological importance to a promising target

Pigment epithelium-derived factor (PEDF) is a non-inhibitory member of the serpin (serine protease inhibitor) family and is a well-known potent anti-tumor factor in a variety of cancers. It has been ascertained that PEDF regulates multiple metastatic processes through various plausible mechanisms, including inhibiting angiogenesis, inducing apoptosis, stimulating extracellular matrix (ECM) degradation, and suppressing the epithelial-to-mesenchymal transition (EMT) process. Although PEDF has been recognized as an anti-metastatic marker in most studies, its role remains controversial with conflicting reports of PEDF as a metastatic marker. The emerging insights into the mechanism(s) of PEDF in tumor progression and its therapeutic effects are discussed systematically in this review, aiming to improve our understanding in the context of metastasis and drug development.

Expression and prognostic roles of PRDXs gene family in hepatocellular carcinoma

Background

As the fourth leading cause of cancer-related death in the world, the therapeutic effect and 5-year overall survival of hepatocellular carcinoma (HCC) are not optimistic. Previous researches indicated that the disorder of PRDXs was related to the occurrence and development of cancers.

Methods

In this study, PRDXs were found in various tumor cell lines by CCLE database analysis. The analysis results of UALCAN, HCCDB and Human Protein Atlas databases showed the expression of PRDXs mRNA and protein in HCC tissues was dysregulated. Besides, UALCAN was used to assess the correlations between PRDXs mRNA as well as methylation levels and clinical characterization.

Results

High expression of PRDX1 or low expression of PRDX2/3 suggested poor prognosis for HCC patients which was demonstrated by Kaplan–Meier Plotter. The genetic alterations and biological interaction network of PRDXs in HCC samples were obtained from c-Bioportal. In addition, LinkedOmics was employed to analyze PRDXs related differentially expressed genes, and on this basis, enrichment of KEGG pathway and miRNAs targets of PRDXs were conducted. The results indicated that these genes were involved in several canonical pathways and certain amino acid metabolism, some of which may effect on the progression of HCC.

Conclusions

In conclusion, the disordered expression of some PRDX family members was associated with the prognosis of HCC patients, suggesting that these PRDX family members may become new molecular targets for the treatment and prognosis prediction of HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02792-8.

Identification of potential salivary biomarker panels for oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide with the maximum number of incidences and deaths reported from India. One of the major causes of poor survival rate associated with OSCC has been attributed to late presentation due to non-availability of a biomarker. Identification of early diagnostic biomarker will help in reducing the disease morbidity and mortality. We validated 12 salivary proteins using targeted proteomics, identified initially by relative quantification of salivary proteins on LC-MS, in OSCC patients and controls. Salivary AHSG (p = 0.0041**) and KRT6C (p = 0.002**) were upregulated in OSCC cases and AZGP1 (p ≤ 0.0001***), KLK1 (p = 0.006**) and BPIFB2 (p = 0.0061**) were downregulated. Regression modelling resulted in a significant risk prediction model (p < 0.0001***) consisting of AZGP1, AHSG and KRT6C for which ROC curve had AUC, sensitivity and specificity of 82.4%, 78% and 73.5% respectively for all OSCC cases and 87.9%, 87.5% and 73.5% respectively for late stage (T3/T4) OSCC. AZGP1, AHSG, KRT6C and BPIFB2 together resulted in ROC curve (p < 0.0001***) with AUC, sensitivity and specificity of 94%, 100% and 77.6% respectively for N0 cases while KRT6C and AZGP1 for N+ cases with ROC curve (p < 0.0001***) having AUC sensitivity and specificity of 76.8%, 73% and 69.4%. Our data aids in the identification of biomarker panels for the diagnosis of OSCC cases with a differential diagnosis between early and late-stage cases.

Urinary proteomic profiles of prostate cancer with different risk of progression and correlation with histopathological features

Prostate cancer (PCa) is the most common tumor in men with extremely variable outcome, varying from latent or indolent form to very aggressive behavior. High grade tumors, expansions exceeding the prostatic capsule into the surrounding soft tissues and spreading through lymph vascular channels, represent the most consistent unfavorable prognostic factors. However, accuracy in the prediction of the disease progression is sometimes difficult. Along with new molecular diagnostic techniques and more accurate histopathological approaches, proteomic studies challenge to identify potential biomarkers predictive of PCa progression. In our study we analyzed the urinary proteomes of 42 patients affected by PCa through two-dimensional electrophoresis associated with mass spectrometry. Proteomic profiles were correlated to histopathological features including pTNM stage and tumor differentiation in order to provide new promising markers able to define more accurately the PCa aggressiveness and driving new therapeutic approaches.

A Meta-Analysis of Proteomic Blood Markers of Colorectal Cancer

BACKGROUND

Early diagnosis will significantly improve the survival rate of colorectal cancer (CRC); however, the existing methods for CRC screening were either invasive or inefficient. There is an emergency need for novel markers in CRC's early diagnosis. Serum proteomics has gained great potential in discovering novel markers, providing markers that reflect the early stage of cancer and prognosis prediction of CRC. In this paper, the results of proteomics of CRC studies were summarized through a meta-analysis in order to obtain the diagnostic efficiency of novel markers.

METHODS

A systematic search on bibliographic databases was performed to collect the studies that explore blood-based markers for CRC applying proteomics. The detection and validation methods, as well as the specificity and sensitivity of the biomarkers in these studies, were evaluated. Newcastle- Ottawa Scale (NOS) case-control studies version was used for quality assessment of included studies.

RESULTS

Thirty-four studies were selected from 751 studies, in which markers detected by proteomics were summarized. In total, fifty-nine proteins were classified according to their biological function. The sensitivity, specificity, or AUC varied among these markers. Among them, Mammalian STE20-like protein kinase 1/ Serine threonine kinase 4 (MST1/STK4), S100 calcium-binding protein A9 (S100A9), and Tissue inhibitor of metalloproteinases 1 (TIMP1) were suitable for effect sizes merging, and their diagnostic efficiencies were recalculated after merging. MST1/STK4 obtained a sensitivity of 68% and a specificity of 78%. S100A9 achieved a sensitivity of 72%, a specificity of 83%, and an AUC of 0.88. TIMP1 obtained a sensitivity of 42%, a specificity of 88%, and an AUC of 0.71.

CONCLUSION

MST1/STK4, S100A9, and TIMP1 showed excellent performance for CRC detection. Several other markers also presented optimized diagnostic efficacy for CRC early detection, but further verification is still needed before they are suitable for clinical use. The discovering of more efficient markers will benefit CRC treatment.

PRDX2 removal inhibits the cell cycle and autophagy in colorectal cancer cells

Colorectal cancer (CRC) is a prevalent worldwide disease in which the antioxidant enzyme peroxiredoxin 2 (PRDX2) plays an important role. To investigate the molecular mechanism of PRDX2 in CRC, we performed bioinformatics analysis of The Cancer Genome Atlas (TCGA) datasets and Gene Expression Omnibus (GEO) DataSets (accession no. GSE81429). Our results suggest that PRDX2 is associated with cell-cycle progression and autophagy activated by the P38 MAPK/FOXO signaling pathway. Using a short-hairpin RNA vector, we verified that PRDX2 is essential for CRC cell proliferation and S-phase progression. Immunostaining, electron microscopy and western blotting assays verified the effect of PRDX2 knockdown on autophagy flux and p38 activation. The P38 activator dehydrocorydaline chloride partially rescued the effects of sh-PRDX2 on the expression of proteins related to cell-cycle progression and autophagy. We verified the correlation between PRDX2 expression and the expression of an array of cell-cycle and autophagy-related genes using data from an independent set of 222 CRC patient samples. A mouse xenoplast model was consistent with in vitro results. Our results suggest that PRDX2 promotes CRC cell-cycle progression via activation of the p38 MAPK pathway.

Peroxiredoxins and Immune Infiltrations in Colon Adenocarcinoma: Their Negative Correlations and Clinical Significances, an In Silico Analysis

Background: Peroxiredoxins (PRDXs) were reported to be associated with inflammation response in previous studies. In colon adenocarcinoma (COAD), however, their correlations and clinical significance were unclear.

Methods: The RNA-seq data of 452 COAD patients with clinical information was downloaded from The Cancer Genome Atlas (TCGA) and transcripts per million (TPM) normalized. Comparisons of relative expressions of PRDXs between COAD tumor and normal controls were applied. PRDXs dy-regulations in COAD were validated via Oncomine, Human Protein Atlas (HPA) and Gene Expression Omnibus (GEO) repository. Through Tumor Immune Estimation Resource (TIMER), the immune estimation of TCGA-COAD patients was downloaded and the dy-regulated PRDXs were analyzed for their correlations with immune infiltrations in COAD. The TCGA-COAD patients were divided into younger group (age≤65 years) and older group (age>65 years) to investigate the prognostic roles of age, TNM stage, dy-regulated PRDXs and the immune infiltrations in different age groups through Kaplan-Meier survival and Cox regression analyses.

Results: Three of the PRDX members showed their expressional differences both at protein and mRNA level. PRDX2 was consistently up-regulated while PRDX6 down-regulated in COAD. PRDX1 was overexpressed (mRNA) while nuclear absent (protein) in the tumor tissues. PRDX1 overexpression and PRDX6 under-expression were also shown in the stem-like colonospheres from colon cancer cells. Via TIMER, PRDX1, PRDX2, and PRDX6 were found to be negatively correlated with the immune infiltrations in COAD. Both in the younger and older patients, TNM stage had prognostic effects on their overall survival (OS) and recurrence-free survival (RFS). CD4⁺ T cell had independent unfavorable effects on OS of the younger patients while age had similar effects on RFS of the older ones. CD8⁺ T cell was independently prognostic for RFS in the two groups.

Conclusions: Late diagnosis indicated poor prognosis in COAD and dy-regulated PRDXs w might be new markers for its early diagnosis. Age was prognostic and should be considered in the treatments of the older patients. Dy-regulated PRDXs were negatively correlated with immune infiltration levels. CD4⁺ T cell and CD8⁺ T cell infiltrations were prognostic in COAD and their potential as immune targets needed further investigation.

Therapeutic Potential of Pigment Epithelium-derived Factor in Cancer

Pigment epithelium-derived factor (PEDF) is one of the serine protease inhibitors with multifunctional properties, which is produced by various types of organs and tissues. There is an accumulating body of evidence that PEDF plays an important role in the maintenance of tissue homeostasis. Indeed, PEDF not only works as an endogenous inhibitor of angiogenesis, but also suppresses oxidative stress, inflammatory and thrombotic reactions in cell culture systems, animal models, and humans. Furthermore, we, along with others, have found that PEDF inhibits proliferation of, and induces apoptotic cell death in, numerous kinds of tumors. In addition, circulating as well as tumor expression levels of PEDF have been inversely associated with tumor growth and metastasis. These observations suggest that supplementation of PEDF proteins and/or enhancement of endogenous PEDF expression could be a novel therapeutic strategy for the treatment of cancer. Therefore, in this paper, we review the effects of PEDF on diverse types of cancer, and discuss its therapeutic perspectives.

Pigment Epithelium-Derived Factor Promotes the Growth and Migration of Human Esophageal Squamous Cell Carcinoma

Pigment epithelium-derived factor (PEDF) is an oncogene found in various types of cancers. However, how PEDF affects the development of human esophageal squamous cell carcinoma (ESCC) is unknown. This study investigates the role of PEDF in ESCC cell proliferation, migration, and cell cycle both in vitro and in vivo. The PEDF expression was examined in patient tumor samples and ESCC cell lines. Short hairpin RNA technology was used to inhibit the PEDF expression in ESCC EC9706 and KYSE150 cells. In vitro cell proliferation and migration assays were performed. The effects of PEDF on tumor growth and progression were examined in vivo in murine subcutaneous xenograft tumor models. It was found that PEDF was overexpressed in esophageal cancer cells and patient tumor tissues compared to normal control samples. PEDF enhanced cell cycle progression and inhibited cell apoptosis. Knock down of PEDF inhibited esophageal cell proliferation and migration in vitro. Moreover, Inhibition of PEDF significantly reduced tumor growth and tumor size in vivo. These results indicate that PEDF induce tumorigenesis in ESCC and can be a potential therapeutic target for cancer treatment.

Zinc-α2-glycoprotein 1 promotes EMT in colorectal cancer by filamin A mediated focal adhesion pathway

Liver metastasis is the main reason for the poor prognosis of colorectal cancer, and identifying molecules involved in liver metastases of colorectal cancer may provide effective therapeutic targets. Zinc-α2-glycoprotein 1(AZGP1) is a candidate biomarker for diagnosis and prognosis in cancer. However, its function and molecular mechanism in metastatic colorectal cancer remains largely unknown. We previously found that up-regulated AZGP1 promotes proliferation, migration and invasion in colorectal cancer cell line, here we elucidated the mechanism of AZGP1 in regulating metastasis. In this article, we found that AZGP1 was also highly expressed in colorectal cancer tissues with liver metastasis relative to those without metastasis, and abundant expression of AZGP1 was associated with poor prognosis, also, AZGP1 down regulation prevented cell metastasis in vivo and in vitro. We further demonstrated that AZGP1 promotes metastasis by regulating the epithelial-mesenchymal transition (EMT) and associating with molecules involved in the focal adhesion pathway, including the adhesion molecule FLNA, which acts as an important protein interactor. More importantly, AZGP1 down regulation inhibited the phosphorylation of FLNA mediated by the restrain of PAK2 kinase, thereby inducing its proteolysis and subsequently affecting its subcellular localization, where it regulates the EMT and promotes metastasis. Collectively, these results highlight AZGP1 as a new and promising therapeutic molecule for liver metastatic colorectal cancer.

Integrated Whole Transcriptome Profiling and Bioinformatics Analysis for Revealing Regulatory Pathways Associated With Quercetin-Induced Apoptosis in HCT-116 Cells

Quercetin (QUE) is a bioactive component that belongs to the natural flavonoids group, and recent researchers found that it could prevent colorectal cancer (CRC). However, the exact mechanism by which QUE exerts its anti-tumor effects in CRC remains unclear. In this study, MTS assay and flow cytometry were used to detect the anti-tumor effects of QUE on HCT-116 cells. The results showed that QUE could inhibit the proliferation and induce apoptosis of HCT-116 cells. Furthermore, whole transcriptome sequencing was employed to establish the microRNA (miRNA), long non-coding RNA (lncRNA), circular RNA (circRNA), and mRNA profiles. A total of 240 differentially expressed lncRNAs (DElncRNAs), 131 circRNAs (DEcircRNAs), 83 miRNAs (DEmiRNAs), and 1415 mRNAs (DEmRNAs) were identified in the QUE-treated HCT-116 cells compared to the untreated HCT-116 cells. Then, quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the expression of selected circRNAs, miRNAs, lncRNAs, and mRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed to further investigate RNAs' biological functions and potential mechanisms. Based on the theory of competing endogenous RNA (ceRNA), the circRNA-miRNA-mRNA and lncRNA-miRNA-mRNA regulatory networks were constructed to illustrate the regulatory relationship between non-coding RNA (ncRNA) and mRNA. Our results provided novel information about the molecular basis of QUE in treating CRC. Our findings indicated that deep RNA sequencing analysis of mRNA and ncRNAs was a promising approach to research anticancer mechanisms.

Multiplexed Electrochemical Cancer Diagnostics With Automated Microfluidics

Microfluidic platforms can lead to miniaturisation, increased throughput and reduced reagent consumption, particularly when the processes are automated. Here, a programmable microcontroller is used for automation of a microfluidic platform configured to electrochemically determine the levels of 8 proteins simultaneously in complex liquid samples. The platform system is composed of a programmable Arduino microcontroller that controls inexpensive valve actuators, pump, magnetic stirrer and electronic display. The programmable microcontroller results in repeatable timing for each step in a complex assay protocol, such as sandwich immunoassays. Application of the platform is demonstrated using a multiplexed electrochemical immunoassay based on capture at the electrode surface of magnetic particles labelled with horseradish peroxidase and detection antibody. The multiplexed assay protocol is completed in less than 30 mins and results in detection of eight proteins associated with prostate cancer. The approach presented can be used to automate and simplify high-throughput screening campaigns, such as detection of multiple biomarkers in patient samples.

MicroRNA-93 promotes bladder cancer proliferation and invasion by targeting PEDF

OBJECTIVE

MicroRNA-93 (miR-93) is upregulated in the urine of patients with bladder cancer (BC). Here, we investigated the role of miR-93 in BC progression and explored the underlying mechanism.

METHODS

miR-93 expression in BC tissues and cells was detected by real time-polymerase chain reaction. The effects of miR-93 and pigment epithelium-derived factor (PEDF) on cell proliferation and invasion were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell assays. The binding of miR-93 to the 3'-untranslated region of PEDF was identified by the luciferase reporter assay.

RESULTS

miR-93 expression was higher in BC tissues than in normal controls, and its expression was associated with tumor stage and node stage. Inhibition of miR-93 suppressed the proliferation and invasion of BC cells. PEDF was identified as a target of miR-93 and shown to mediate the effect of miR-93 on cell proliferation and invasion.

CONCLUSIONS

The present data suggested that miR-93 promoted BC cell proliferation and invasion by targeting PEDF, providing new biomarkers and targets for BC diagnosis and treatment.

The prognostic values of the peroxiredoxins family in ovarian cancer

Purpose: Peroxiredoxins (PRDXs) are a family of antioxidant enzymes with six identified mammalian isoforms (PRDX1-6). PRDX expression is up-regulated in various types of solid tumors; however, individual PRDX expression, and its impact on prognostic value in ovarian cancer patients, remains unclear.Methods: PRDXs family protein expression profiles in normal ovarian tissues and ovarian cancer tissues were examined using the Human Protein Atlas database. Then, the prognostic roles of PRDX family members in several sets of clinical data (histology, pathological grades, clinical stages, and applied chemotherapy) in ovarian cancer patients were investigated using the Kaplan-Meier plotter.Results: PRDXs family protein expression in ovarian cancer tissues was elevated compared with normal ovarian tissues. Meanwhile, elevated expression of PRDX3, PRDX5, and PRDX6 mRNAs showed poorer overall survival (OS); PRDX5 and PRDX6 also predicted poor progression-free survival (PFS) for ovarian cancer patients. Furthermore, PRDX3 played significant prognostic roles, particularly in poor differentiation and late-stage serous ovarian cancer patients. Additionally, PRDX5 predicted a lower PFS in all ovarian cancer patients treated with Platin, Taxol, and Taxol+Platin chemotherapy. PRDX3 and PRDX6 also showed poor PFS in patients treated with Platin chemotherapy. Furthermore, PRDX3 and PRDX5 indicated lower OS in patients treated with these three chemotherapeutic agents. PRDX6 predicted a poorer OS in patients treated with Taxol and Taxol+Platin chemotherapy.Conclusion: These results suggest that there are distinct prognostic values of PRDX family members in patients with ovarian cancer, and that the expression of PRDX3, PRDX5, and PRDX6 mRNAs are a useful prognostic indicator in the effect of chemotherapy in ovarian cancer patients.

Peroxiredoxins in Colorectal Cancer: Predictive Biomarkers of Radiation Response and Therapeutic Targets to Increase Radiation Sensitivity?

Colorectal cancer (CRC) is the third most common cancer in the Western world, with one-third of cases located in the rectum. Preoperative radiotherapy is the standard of care for many patients with rectal cancer but has a highly variable response rate. The ability to predict response would be of great clinical utility. The response of cells to ionizing radiation is known to involve immediate damage to biomolecules and more sustained disruption of redox homeostasis leading to cell death. The peroxiredoxins are an important group of thiol-dependent antioxidants involved in protecting cells from oxidative stress and regulating signaling pathways involved in cellular responses to oxidative stress. All six human peroxiredoxins have shown increased expression in CRC and may be associated with clinicopathological features and tumor response to ionizing radiation. Peroxiredoxins can act as markers of oxidative stress in various biological systems but they have not been investigated in this capacity in CRC. As such, there is currently insufficient evidence to support the role of peroxiredoxins as clinical biomarkers, but it is an area worthy of investigation. Future research should focus on the in vivo response of rectal cancer to radiotherapy and the redox status of peroxiredoxins in rectal cancer cells, in order to predict response to radiotherapy. The peroxiredoxin system is also a potential therapeutic target for CRC.

Impact of pigment epithelium-derived factor on colorectal cancer in vitro and in vivo

Pigment epithelial derived factor (PEDF) is a secreted glycoprotein that is a non-inhibitory member of the serine protease inhibitor (serpin) family. PEDF exhibits multiple biological properties including neuroprotective, anti-angiogenic, and immune-modulating. Interestingly, PEDF exerts the inhibitory effects in cancers derived from certain tissues, including prostatic, ovarian, and pancreatic carcinomas. The current study aimed to elucidate its role in colorectal cancer development. PEDF expression in human colorectal cancer tissue was assessed using quantitative polymerase chain reaction (qPCR) and immunohistochemical staining (IHC). The effect of treatment with recombinant PEDF on cellular function was examined using in vitro functional assays. PEDF expression was downregulated in colorectal cancer cell tissue. Treatment with recombinant PEDF resulted in significant decreases in the rate of colorectal cancer cell migration and invasion and an increase in cellular adhesion in colorectal cancer cell lines examined. These results indicate that upregulation of PEDF expression may serve as a new strategy for further investigation of therapeutic relevance to the prevention of the metastatic spread of colorectal cancer.

AZGP1 inhibits soft tissue sarcoma cells invasion and migration

Background

One of the major challenges in soft tissue sarcomas is to identify factors that predict metastasis. AZGP1 is a potential biomarker of cancer progression, but its value in soft tissue sarcomas remains unknown. The aim of this study is to determine the expression level of AZGP1 in soft tissue sarcomas, and to analyze its influence on tumor progression.

Methods

AZGP1 immunohistochemistry (IHC) and RT-PCR were performed in 86 patients with soft tissue sarcomas. The relationships between AZGP1 levels and clinicopathologic features were analyzed. In vitro experiments were performed using fibrosarcoma (HT1080), rhabdomyosarcoma (RD) and synovial sarcoma (SW982) cell lines to corroborate our findings. We used lentiviral over-expression and knockdown assays to examine how changes of AZGP1 expressions might affect cellular migration and invasion.

Results

The quantitative RT-PCR results showed that AZGP1 expression was negatively correlated with metastasis and overall survival in soft tissue sarcomas (p < 0.05). Immunohistochemical staining showed lower expression of AZGP1 in patients with metastasis than in those without. Kaplan-Meier survival analysis showed that patients with low expression of AZGP1 had shorter overall (p = 0.056) and metastasis-free survivals (p = 0.038). These findings were corroborated by our in vitro experiments. Over-expression of AZGP1 significantly decreased RD cellular migration and invasion by 64% and 78%, respectively. HT1080 cells migration was inhibited by 2-fold, whereas their invasion was repressed by 7-fold after AZGP1 knockdown.

Conclusions

Our study reveals that reduced AZGP1 expression correlates with in vitro cellular migration and invasion. In vivo, it is associated with higher metastatic risk and shorter survival in patients with soft tissue sarcomas.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3962-5) contains supplementary material, which is available to authorized users.

Circulating and Adipose Tissue mRNA Levels of Zinc-α2-Glycoprotein, Leptin, High-Molecular-Weight Adiponectin, and Tumor Necrosis Factor-Alpha in Colorectal Cancer Patients With or Without Obesity

OBJECTIVES

To explore zinc-α2-glycoprotein (ZAG), leptin, high-molecular-weight adiponectin (HMW-ADPN), and tumor necrosis factor-alpha (TNF-α) levels in serum and subcutaneous and visceral white adipose tissue (sWAT and vWAT) among normal weight (NW) and overweight/obese (OW/OB) patients with colorectal cancer (CRC).

METHODS

A total of 76 Chinese CRC patients (42 NW + CRC, 34 OW/OB + CRC) and 40 healthy controls were recruited. Serum levels of the adipokines of interest were measured by an enzyme-linked immunosorbent assay method, and their mRNA levels in sWAT and vWAT were determined by reverse transcription quantitative PCR methods.

RESULTS

Serum ZAG levels in the NW + CRC group were significantly increased by 11.7% compared with the healthy controls. Serum leptin levels in the OW/OB + CRC group were found to be increased by 57.7%, while HMW-ADPN levels were decreased by 23.5% when compared with the NW + CRC group of CRC patients. Additionally, ZAG mRNA levels in sWAT were significantly reduced by 78.8% in OB + CRC in comparison with NW + CRC patients. ZAG mRNA levels were negatively associated with body mass index (BMI) in sWAT but positively correlated with BMI in vWAT. TNF-α mRNA levels in vWAT of OB + CRC patients were significantly increased by 2.8-fold when compared with NW + CRC patients. In particular, CRC was independently associated with serum ZAG levels. The risk of CRC in participants with high tertile serum ZAG levels was 5.84-fold higher than in those with low tertile ZAG levels after adjusting for age, gender, and other confounders [odds ratio (OR) = 6.84, 95% confidence interval (CI) 1.70-27.54, P = 0.03]. The CRC risk in participants with high tertile leptin levels was only 10.7% of those with low tertile leptin levels (OR = 0.11, 95% CI 0.01-0.89, P = 0.04). The area under the receiver operating characteristic (ROC) curve of ZAG was 0.66 (95% CI 0.54-0.77, P < 0.05). At the cutoff value of 1.42 µg/mL serum ZAG, the sensitivity and specificity for differentiating patients with CRC from controls were 62.2 and 69.2%, respectively.

CONCLUSION

Serum ZAG levels were significantly increased in CRC patients. Subjects with higher circulating ZAG and lower leptin levels were more likely to have CRC than those with lower ZAG and higher leptin levels. Serum ZAG might be a potential diagnostic biomarker for CRC in the Chinese population.

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.

Cell Line Secretome and Tumor Tissue Proteome Markers for Early Detection of Colorectal Cancer: A Systematic Review

Objective: In order to find low abundant proteins secretome and tumor tissue proteome data have been explored in the last few years for the diagnosis of colorectal cancer (CRC). In this review we aim to summarize the results of studies evaluating markers derived from the secretome and tumor proteome for blood based detection of colorectal cancer. Methods: Observing the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines PubMed and Web of Science databases were searched systematically for relevant studies published up to 18 July 2017. After screening for predefined eligibility criteria a total of 47 studies were identified. Information on diagnostic performance indicators, methodological procedures and validation was extracted. Functions of proteins were identified from the UniProt database and the the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was used to assess study quality. Results: Forty seven studies meeting inclusion criteria were identified. Overall, 83 different proteins were identified, with carcinoembryonic Antigen (CEA) being by far the most commonly reported (reported in 24 studies). Evaluation of the markers or marker combinations in blood samples from CRC cases and controls yielded apparently very promising diagnostic performances, with area under the curve >0.9 in several cases, but lack of internal or external validation, overoptimism due to overfitting and spectrum bias due to evaluation in clinical setting rather than screening settings are major concerns. Conclusions: Secretome and tumor proteome-based biomarkers when validated in blood yield promising candidates. However, for discovered protein markers to be clinically applicable as screening tool they have to be specific for early stages and need to be validated externally in larger studies with participants recruited in true screening setting.

Downregulation of AZGP1 by Ikaros and histone deacetylase promotes tumor progression through the PTEN/Akt and CD44s pathways in hepatocellular carcinoma

Increasing evidence has shown that zinc-alpha2-glycoprotein (AZGP1) is associated with the progression and prognosis of several tumor types. However, little is known regarding the underlying molecular mechanisms of AZGP1 in hepatocellular carcinoma (HCC). In this study, we report that transcription factor Ikaros bound to the AZGP1 promoter and increased its expression in HCC cells. The downregulation of AZGP1 was associated with histone deacetylation in HCC. In addition, the positive feedback regulation via acetylation of histone H4-mediated transactivation of the Ikaros promoter and the Ikaros-mediated transactivation of the acetylation of histone H4 were crucial for regulating AZGP1 expression in HCC cells. Moreover, low serum AZGP1 level in HCC patients was associated with poor prognosis. The ectopic overexpression of AZGP1 or recombinant AZGP1 protein inhibited HCC cell proliferation, migration and invasion in vitro and in vivo, whereas silencing AZGP1 expression resulted in increased cell proliferation, migration and invasion in vitro. In addition, we found that AZGP1 inhibited cell migration and invasion through the regulation of the PTEN/Akt and CD44s pathways. Collectively, our findings revealed the molecular mechanism of AZGP1 expression in HCC, providing new insights into the mechanisms underlying tumor progression.

Deficiency of pigment epithelium-derived factor in nasopharyngeal carcinoma cells triggers the epithelial-mesenchymal transition and metastasis

Distant metastasis is the primary cause of nasopharyngeal carcinoma (NPC) treatment failure while epithelial-mesenchymal transition (EMT) is the critical process of NPC invasion and metastasis. However, tumor-suppressor genes involved in the EMT and metastasis of NPC have not been explored clearly compared with the oncogenes. In the present study, the expression of pigment epithelium-derived factor (PEDF), a potent endogenous antitumor factor, was diminished in human NPC tissues and associated with clinicopathological and EMT features. The knockdown of PEDF induced EMT in lower metastatic NPC cell lines and overexpression of PEDF restored epithelial phenotype in higher metastatic NPC cell lines with typical EMT. The inhibition of PEDF mediated NPC cell spontaneous metastasis in vivo. LRP6/GSK3β/β-catenin signal pathway rather than AKT/GSK3β pathway was involved in the effects of PEDF on EMT. The expression of PEDF was directly downregulated by elevated miR-320c in NPC. In conclusion, our findings indicate for the first time that PEDF functions as tumor-suppressor gene in the occurrence of EMT and metastasis in NPC. PEDF could serve as a promising candidate for NPC diagnosis, prognosis and treatment.

Reduction of AZGP1 predicts poor prognosis in esophageal squamous cell carcinoma patients in Northern China

BACKGROUND

As a key regulator in lipid mobilization, AZGP1 has been reported to play a significant role in various cancers. This study was carried out to investigate the role of AZGP1 in the development of esophageal squamous cell carcinoma (ESCC) patients in Northern China.

MATERIALS AND METHODS

Through the application of quantitative real-time polymerase chain reaction and immunohistochemical staining, AZGP1 expression in ESCC tissues from Northern China was examined.

RESULTS

Decreased expression of AZGP1 was observed in ~60% ESCC patients. AZGP1 downregulation was significantly associated with lymph node metastasis (P=0.035), advanced clinical stage (P=0.018), poor prognosis for 5-year disease-specific survival (DSS; P<0.001), local recurrence-free survival (LRFS; P=0.016), and metastasis-free survival (MeFS; P=0.014). In addition, Cox multivariate analysis revealed that AZGP1 downregulation remained to be an independent prognosticator for shorter DSS (P=0.001), LRFS (P=0.011), and MeFS (P=0.004).

CONCLUSION

AZGP1 might be a candidate tumor suppressor and a potential novel prognostic biomarker for ESCC patients in Northern China.

Integrated analysis identified an intestinal-like and a diffuse-like gene sets that predict gastric cancer outcome

The two major histological types of gastric cancer, intestinal and diffuse subtypes, have distinct epidemiological and pathophysiological features and were also suggested to be of diverse clinical outcomes. Although the gene expression spectrum of gastric cancer subtypes has been reported by previous studies, its linkage with gastric cancer clinical features and outcomes remains elusive. We investigated large-sample online gastric cancer datasets for seeking genes correlated with the clinical diversities between gastric cancer intestinal and diffuse subtypes. Genes differently expressed between the two subtypes were assessed by multiple statistical analysis and were testified on cellular level by quantitative RT-PCR. Related genes were combined to generate a risk signature, and their mutual linkages were also explored. Among genes overexpressed in intestinal subtype, ATPIF1, PRDX2, PRKAR2A, and SMC1A were correlated with positive prognosis. Among genes overexpressed in diffuse subtype, DTNA, GPR161, IDS, RHOQ, and TSHZ2 were correlated with negative prognosis. These nine genes were all novel independent prognostic factors. When used in combination as signatures, these two gene sets displayed strong efficacy for prediction of the prognosis and clinical variables in gastric and colorectal cancer. Hence, these two genes sets were respectively defined as the favorable intestinal-like and adverse diffuse-like gene sets. We identified nine novel genes correlated with the clinical diversity between the intestinal and diffuse subtypes of gastric cancer. The malignant changes from the intestinal to diffuse subtype might be due to the reduction of the four intestinal-like genes, as well as the elevation of the five diffuse-like genes.

Effect of purified fractions from cell culture supernate of high-density pre-B acute lymphoblastic leukemia cells (ALL3) on the growth of ALL3 cells at low density

The mechanisms underlying the aberrant growth and interactions between cells are not understood very well. The pre-B acute lymphoblastic leukemia cells directly obtained from an adult patient grow very poorly or do not grow at all at low density (LD), but grow better at high starting cell density (HD). We found that the LD ALL3 cells can be stimulated to grow in the presence of diffusible, soluble factors secreted by ALL3 cells themselves growing at high starting cell density. We then developed a biochemical purification procedure that allowed us to purify the factor(s) with stimulatory activity and analyzed them by nanoliquid chromatography-tandem mass spectrometry (nanoLC-MS/MS). Using nanoLC-MS/MS we have identified several proteins which were further processed using various bioinformatics tools. This resulted in eight protein candidates which might be responsible for the growth activity on non-growing LD ALL3 cells and their involvement in the stimulatory activity are discussed.

Quantitative proteomic analysis exploring progression of colorectal cancer: Modulation of the serpin family

Colorectal cancer (CRC) remains a major cause of cancer related-death in developed countries. The mortality risk is correlated with the stage of CRC determined at the primary diagnosis and early diagnosis is associated with enhanced survival rate. Currently, only faecal occult blood tests are used to screen for CRC. Consequently, there is an incentive to identify specific markers of CRC. We used quantitative proteomic analysis of serum samples to characterize protein profiles in adenoma, CRC and healthy control samples. We identified 89 distinct proteins modulated between normal, colorectal adenoma and carcinoma patients. This list emphasizes proteins involved in enzyme regulator activities and in particular the serpin family. In serum samples, protein profiles of three members of the serpin family (SERPINA1, SERPINA3 and SERPINC1) were confirmed by ELISA assays. We obtained sensitivity/specificity values of 95%/95% for both SERPINA1 and SERPINC1, and 95%/55% for SERPINA3. This study supports the idea that serum proteins can discriminate adenoma and CRC patients from unaffected patients and reveals a panel of regulated proteins that might be useful for selecting patients for colonoscopy. By evaluating SERPINA1, SERPINA3 and SERPINC1, we highlight the potential role of the serpin family during the development and progression of CRC.

SIGNIFICANCE

Colorectal cancer (CRC) remains a major cause of cancer mortality throughout the world. However, very few CRC biomarkers have satisfactory sensitivity and specificity in clinical practice. To the best of our knowledge our study is the first to profile sera proteomes between adenoma, CRC and healthy patients. We report a comprehensive list of proteins that may be used as early diagnostic biomarkers of CRC. It is noteworthy that 17% of these modulated proteins have been previously described as candidate biomarkers in CRC. Enzyme regulator activity was found to be the main molecular function among these proteins and, in particular, there was an enrichment of members of the serpin family. The subsequent verification on a new cohort by ELISA demonstrates that these serpins could be useful to discriminate healthy from colorectal carcinoma patients with a high sensitivity and specificity. The combination of these biomarkers should increase predictive powers of CRC diagnosis. The remaining candidates form a reserve for further evaluation of additional biomarkers for CRC diagnosis.

AZGP1 suppresses epithelial-to-mesenchymal transition and hepatic carcinogenesis by blocking TGFβ1-ERK2 pathways

Zinc-α2-glycoprotein 1 (AZGP1) has been found to play important roles in TGF-β1 induced epithelial-to-mesenchymal transition (EMT). However, the mechanisms of AZGP1 inhibiting EMT and its therapeutic potential remain unknown in hepatocellular carcinoma (HCC). AZGP1, TGF-β1 or ERK2 expressions were examined in liver tissues of HCC patients and rat model. The effect of AZGP1 on EMT and crosstalking of TGFβ1-ERK2 signaling in human hepatic cancer cell was tested in vitro and in vivo. Hepatic expression of AZGP1 was nearly deficient in HCC patients and rats. It was proved that AZGP1 has the ability of down-regulating mesenchymal markers, up-regulating epithelial marker, inhibiting cell invasion and suppressing EMT in human HCC cells. The results clarified that AZGP1 has the effect on blocking TGF-β1 mediated ERK2 phosphorylation leading to depressing EMT and invasive potential in vitro. Local injection of AZGP1 mimic in vivo could significantly withhold lung metastasis in HCC. In conclusion, loss of AZGP1 could trigger EMT induced by TGFβ1-ERK2 signaling, confuse in energy metabolism, reduce cell proliferation and apoptosis, activate survival signals and promote invasion. Up-regulation of AZGP1 should be proposed to reverse EMT and might be a new promising therapy for HCC.

The sulfiredoxin-peroxiredoxin (Srx-Prx) axis in cell signal transduction and cancer development

Redox signaling is a critical component of cell signaling pathways that are involved in the regulation of cell growth, metabolism, hormone signaling, immune regulation and variety of other physiological functions. Peroxiredoxin (Prx) is a family of thiol-based peroxidase that acts as a regulator of redox signaling. Members of Prx family can act as antioxidants and chaperones. Sulfiredoxin (Srx) is an antioxidant protein that exclusively reduces over-oxidized typical 2-Cys Prx. Srx has different affinities for individual Prx and it also catalyzes the deglutathionylation of variety of substrates. Individual component of the Srx-Prx system plays critical role in carcinogenesis by modulating cell signaling pathways involved in cell proliferation, migration and metastasis. Expression levels of individual component of the Srx-Prx axis have been correlated with patient survival outcome in multiple cancer types. This review will summarize the molecular basis of differences in the affinity of Srx for individual Prx and the role of individual component of the Srx-Prx system in tumor progression and metastasis. This enhanced understanding of molecular aspects of Srx-Prx interaction and its role in cell signal transduction will help define the Srx-Prx system as a future therapeutic target in human cancer.

Zinc-α-2-glycoprotein: a candidate biomarker for colon cancer diagnosis in Chinese population

Zinc-α-2-glycoprotein (AZGP1) is a 41-kDa secreted glycoprotein, which has been detected in several malignancies. The diagnostic value of AZGP1 in serum of prostate and breast cancer patients has been reported. Analyzing “The Cancer Genome Atlas” data, we found that in colon cancer AZGP1 gene expression was upregulated at transcriptional level. We hypothesized that AZGP1 could be used as a diagnostic marker of colon cancer. First, we confirmed AZGP1 expression was higher in a set of 28 tumor tissues than in normal colonic mucosa tissues by real-time quantitative PCR and western blot in a Chinese population. We verified that serum concentration of AZGP1 was higher in 120 colon cancer patients compared with 40 healthy controls by ELISA (p < 0.001). Then receiver-operating characteristic (ROC) curve analysis was used to evaluate the predictive diagnostic value of AZGP1 in serum. The area under the curve (AUC) of AZGP1 was 0.742 (p < 0.001, 95% confidence interval (CI) = 0.656–0.827) in between the AUC of carcinoembryonic antigen (CEA) and the AUC of CA19-9, suggesting that predictive diagnostic value of AZGP1 is between CEA and Carbohydrate 19-9 (CA19-9). The combination of AZGP1 with traditional serum biomarkers, CEA and CA19-9, could result in better diagnostic results. To further validate the diagnostic value of AZGP1, a tissue microarray containing 190 samples of primary colon cancer tissue paired with normal colonic tissue was analysed and the result showed that AZGP1 was significantly upregulated in 68.4% (130 of 190) of the primary cancer lesions. In contrast, there was a weakly positive staining in 29.5% (56 of 190) of the normal colonic tissue samples (p < 0.001). Leave-one-out cross-validation was performed on the serum data, and showed that the diagnostic value of AZGP1 had 63.3% sensitivity and 65.0% specificity. Combination of AZGP1, CEA and CA19-9 had improved diagnosis value accuracy with 74.2% sensitivity and 72.5% specificity. These results suggest that AZGP1 is a useful diagnostic biomarker in tissues and serum from a Chinese population.

Clinical potential role of circulating microRNAs in early diagnosis of colorectal cancer patients

Current procedures for diagnosis and biomarker examination of colorectal cancer (CRC) are invasive and unpleasant. There is a great need to identify sensitive and specific biomarkers for early diagnosis of CRC. Circulating microRNAs (miRNAs) are promising molecular markers for CRC prediction. We performed a comprehensive meta-analysis to integrate an evaluation index for diagnostic accuracy of circulating miRNAs in diagnosing CRC patients. Furthermore, we conducted an independent validation set of 49 CRC patients and 49 healthy controls. In our meta-analysis, we found that miR-21 yielded a pooled area under ROC curve (AUC) of 0.867 (sensitivity: 76%, specificity: 82%) in discriminating CRC from controls, and miR-92a yielded a summary AUC of 0.803 (sensitivity: 77%, specificity: 68%); miR-21 had a higher diagnostic efficiency than miR-92a. In the further validation, plasma miR-21 levels in CRC patients were significantly higher than levels observed in healthy subjects. A ROC curve analysis showed a consistent result. However, this phenotype was not present in miR-92a. Moreover, the expression trend of miR-21 in plasma samples was in line with that of tissue samples, along with the cellular level. Current evidences suggest that plasma miR-21 could be a reliable and non-invasive biomarker for CRC diagnosis. Studies with larger cohorts that include the diagnostic value of plasma miR-21 for CRC are warranted.

Alpha-2-glycoprotein 1(AZGP1) regulates biological behaviors of LoVo cells by down-regulating mTOR signaling pathway and endogenous fatty acid synthesis

AZGP1 is a multifaceted protein associated with lipid mobilization, a process that is regulated by FASN and other metabolic pathways such as mTOR signaling. The active mTOR signaling pathway has been found to be involved in a variety of tumors. However, it remains unclear whether it is involved in the regulation of AZGP1 and FASN. An AZGP1-expressing plasmid was transfected into a human colorectal cancer cell line (LoVo) with a low expression of AZGP1. The expression of AZGP1, FASN, eIF4E, p-mTOR, p-S6,and S6K1 were measured by Western blot analysis, and target genes were detected by RT-PCR. Cell proliferation was studied using the MTT and colony formation assays. The analysis of apoptosis and the cell cycle phase were assessed by flow cytometry. The capacity of cell migration was investigated using the transwell migration assay. We found that the expression of AZGP1 was up-regulated while the expression of FASN, eIF4E, p-mTOR, p-S6, and S6K1 were down-regulated in LoVo cells after AZGP1 was expressed. The proliferation of malignant cells was reduced in AZGP1-overexpression cells, which is consistent with an increased in the G2-arrest and apoptosis rate. Furthermore, the migration of AZGP1-overexpression cells was decreased. The overexpression of AZGP1 suppressed the activation of the mTOR pathway and endogenous FASN-regulated fatty acid synthesis, mitigating the malignant phenotype of LoVo cells. Herein, we provide evidence that AZGP1 may constitute a novel tumor suppressor for LoVo colorectal cancer cells.

Proteomics, genomics and transcriptomics: their emerging roles in the discovery and validation of colorectal cancer biomarkers

Colorectal cancer (CRC) is the second most common cancer in females and the third in males. Since CRC is often diagnosed at an advanced stage when prognosis is poor, identification of biomarkers for early diagnosis is urgently required. Recent advances in proteomics, genomics and transcriptomics have facilitated high-throughput profiling of data generated from CRC-related genes and proteins, providing a window of information for biomarker discovery and validation. However, transfer of candidate biomarkers from bench to bedside remains a dilemma. In this review, we will discuss emerging proteomic technologies and highlight various sample types utilized for proteomics-based identification of CRC biomarkers. Moreover, recent breakthroughs in genomics and transcriptomics for the identification of CRC biomarkers, with particular emphasis on the merits of emerging methylomic and miRNAomic strategies, will be discussed. Integration of proteomics, genomics and transcriptomics will facilitate the discovery and validation of CRC biomarkers leading to the emergence of personalized medicine.

PRDX1 and PRDX6 are repressed in papillary thyroid carcinomas via BRAF V600E-dependent and -independent mechanisms

Many clinical studies highlight the dichotomous role of PRDXs in human cancers, where they can exhibit strong tumor-suppressive or tumor-promoting functions. Recent evidence suggests that lower expression of PRDXs correlates with cancer progression in colorectal cancer (CRC) or in esophageal squamous carcinoma. In the thyroid, increased levels of PRDX1 has been described in follicular adenomas and carcinomas, as well as in thyroiditis, while reduced levels of PRDX6 has been found in follicular adenomas. We studied the expression of PRDX1 and PRDX6, in a series of thyroid tissue samples, covering different thyroid diseases, including 13 papillary thyroid carcinomas (PTCs). Our results show that PRDX1 and PRDX6 are significantly reduced in all PTCs compared to normal tissues, to non-neoplastic tissue (MNG) or follicular neoplasms. This reduction is strongly evident in PTCs harboring BRAF V600E (31% of our cases). Using TPC-1 and BCPAP and FRTL-5 cell lines, we demonstrate for the first time that the presence of BRAF V600E is responsible of the hypoexpression of PRDX1 and PRDX6 both at mRNA and protein levels. Finally, independently of BRAF status, we observe an interesting correlation between the tumor size, the presence of lymph node metastasis and the lowest PRDX1 and PRDX6 levels. Therefore, these data indicate that PRDX1 and PRDX6 expression not only may play a key role in papillary thyroid carcinogenesis via a BRAF V600E-dependent mechanism, but their determination could be considered as potential tumor marker for indicating tumor progression in PTCs, independently of BRAF status.

The effects of PEDF on cancer biology: mechanisms of action and therapeutic potential

The potent actions of pigment epithelium-derived factor (PEDF) on tumour-associated cells, and its extracellular localization and secretion, stimulated research on this multifunctional serpin. Such studies have identified several PEDF receptors and downstream signalling pathways. Known cellular PEDF responses have expanded from the initial discovery that PEDF induces retinoblastoma cell differentiation to its anti-angiogenic, antitumorigenic and antimetastatic properties. Although the diversity of PEDF activities seems to be complex, they are consistent with the varied mechanisms that regulate this multimodal factor. If PEDF is to be used for cancer management, a deeper appreciation of its many functions and mechanisms of action is needed.