Transcriptome profiling of whole blood cells identifies PLEK2 and C1QB in human melanoma

PLEK2 activates the PI3K/AKT signaling pathway to drive lung adenocarcinoma progression by upregulating SPC25

Lung adenocarcinoma (LUAD) is the most common subtype of NSCLC, characterized by poor prognosis and frequently diagnosed at advanced. While previous studies have demonstrated pleckstrin-2 (PLEK2) as aberrantly expressed and implicated in tumorigenesis across various tumor types, including LUAD, the molecular mechanisms underlying PLEK2-mediated LUAD progression remain incompletely understood. In this study, we obtained data from The Cancer Genome Atlas (TCGA) database to assess PLEK2 expression in LUAD, a finding further confirmed through analysis of human tissue specimens. PLEK2-silenced LUAD cellular models were subsequently constructed to examine the functional role of PLEK2 both in vitro and in vivo. Our results showed elevated PLEK2 expression in LUAD, correlating with poor patients' prognosis. PLEK2 knockdown led to a significant suppression of LUAD cell proliferation and migration, accompanied by enhanced apoptosis. Moreover, tumor growth in mice injected with PLEK2-silencing LUAD cells was impaired. Gene expression profiling and Co-IP assays suggested direct interaction between PLEK2 and SPC25, with downregulation of SPC25 similarly impairing cell proliferation and migration. Additionally, we revealed phosphoinositide 3-kinase (PI3K)/AKT signaling activation as requisite for PLEK2-induced malignant phenotypes in LUAD. Collectively, our findings underscore PLEK2's oncogenic potential in LUAD, suggesting its utility as a prognostic indicator and therapeutic target for LUAD management.

PLEK2 promotes migration and invasion in pancreatic ductal adenocarcinoma by MMP1 through IL-17 pathway

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognosis primarily due to metastasis. Accumulating evidence suggests that PLEK2 acts as an oncogene in various tumors. This study aimed to investigate the effects of PLEK2 on PDAC. Expression analysis of PLEK2 was conducted using qRT-PCR, Western blot, and immunohistochemistry in PDAC. Wound healing and transwell assays were performed to evaluate the impact of PLEK2 on cell migration and invasion. A xenograft tumor model was employed to assess the in vivo proliferation of PLEK2. Additionally, the downstream pathway of PLEK2 was analyzed through RNA-seq and confirmed by Western blot analysis. The results demonstrated the upregulation of PLEK2 expression in tumor specimens. High PLEK2 expression was significantly associated with poor overall survival and advanced TNM stages. Correlation analyses revealed positive correlations between PLEK2 and TGF-β, EGFR, and MMP1. Wound healing and transwell assays demonstrated that PLEK2 promoted PDAC cell migration and invasion, potentially through the activation of the epithelial-to-mesenchymal transition process. The in vivo experiment further confirmed that PLEK2 knockdown suppressed tumor growth. RNA-seq analysis revealed PLEK2's regulation of MMP1 and activation of p-ERK and p-STAT3, which were verified by Western blot analysis. Overall, the present study suggests that PLEK2 may play a tumor-promoting role in PDAC. These findings provide valuable insights into the molecular mechanisms of pancreatic cancer and highlight the potential of PLEK2 as a therapeutic target.

CTLA4 mRNA is downregulated by miR-155 in regulatory T cells, and reduced blood CTLA4 levels are associated with poor prognosis in metastatic melanoma patients

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is an immune checkpoint expressed in regulatory T (Treg) cells and activated T lymphocytes. Despite its potential as a treatment strategy for melanoma, CTLA-4 inhibition has limited efficacy. Using data from The Cancer Genome Atlas (TCGA) melanoma database and another dataset, we found that decreased CTLA4 mRNA was associated with a poorer prognosis in metastatic melanoma. To investigate further, we measured blood CTLA4 mRNA in 273 whole-blood samples from an Australian cohort and found that it was lower in metastatic melanoma than in healthy controls and associated with worse patient survival. We confirmed these findings using Cox proportional hazards model analysis and another cohort from the US. Fractionated blood analysis revealed that Treg cells were responsible for the downregulated CTLA4 in metastatic melanoma patients, which was confirmed by further analysis of published data showing downregulated CTLA-4 surface protein expression in Treg cells of metastatic melanoma compared to healthy donors. Mechanistically, we found that secretomes from human metastatic melanoma cells downregulate CTLA4 mRNA at the post-transcriptional level through miR-155 while upregulating FOXP3 expression in human Treg cells. Functionally, we demonstrated that CTLA4 expression inhibits the proliferation and suppressive function of human Treg cells. Finally, miR-155 was found to be upregulated in Treg cells from metastatic melanoma patients compared to healthy donors. Our study provides new insights into the underlying mechanisms of reduced CTLA4 expression observed in melanoma patients, demonstrating that post-transcriptional silencing of CTLA4 by miRNA-155 in Treg cells may play a critical role. Since CTLA-4 expression is downregulated in non-responder melanoma patients to anti-PD-1 immunotherapy, targeting miRNA-155 or other factors involved in regulating CTLA4 expression in Treg cells without affecting T cells could be a potential strategy to improve the efficacy of immunotherapy in melanoma. Further research is needed to understand the molecular mechanisms regulating CTLA4 expression in Treg cells and identify potential therapeutic targets for enhancing immune-based therapies.

5-mRNA-based prognostic signature of survival in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the most common non-small-cell lung cancer, with a high incidence and a poor prognosis.

AIM

To construct effective predictive models to evaluate the prognosis of LUAD patients.

METHODS

In this study, we thoroughly mined LUAD genomic data from the Gene Expression Omnibus (GEO) (GSE43458, GSE32863, and GSE27262) and the Cancer Genome Atlas (TCGA) datasets, including 698 LUAD and 172 healthy (or adjacent normal) lung tissue samples. Univariate regression and LASSO regression analyses were used to screen differentially expressed genes (DEGs) related to patient prognosis, and multivariate Cox regression analysis was applied to establish the risk score equation and construct the survival prognosis model. Receiver operating characteristic curve and Kaplan-Meier survival analyses with clinically independent prognostic parameters were performed to verify the predictive power of the model and further establish a prognostic nomogram.

RESULTS

A total of 380 DEGs were identified in LUAD tissues through GEO and TCGA datasets, and 5 DEGs (TCN1, CENPF, MAOB, CRTAC1 and PLEK2) were screened out by multivariate Cox regression analysis, indicating that the prognostic risk model could be used as an independent prognostic factor (Hazard ratio = 1.520, P < 0.001). Internal and external validation of the model confirmed that the prediction model had good sensitivity and specificity (Area under the curve = 0.754, 0.737). Combining genetic models and clinical prognostic factors, nomograms can also predict overall survival more effectively.

CONCLUSION

A 5-mRNA-based model was constructed to predict the prognosis of lung adenocarcinoma, which may provide clinicians with reliable prognostic assessment tools and help clinical treatment decisions.

A circadian rhythm-related biomarker for predicting prognosis and immunotherapy efficacy in lung adenocarcinoma

Lung adenocarcinoma (LUAD) remains a major reason of cancer-associated mortality globally, and there exists a lack of indicators for survival in LUAD patients. Therefore, it is clinically required to obtain a novel prognostically indicator for guiding clinical management. In this study, we established a circadian rhythm (CR) related signature by a combinative investigation of multiple datasets. The newly-established signature showed an acceptable ability to predict survival and could serve as an independent indicator for prognosis. Moreover, the newly-established signature was critically associated with tumor malignancy, including proliferation, invasion, EMT and metastasis. The newly-established signature was predictive of response to immune checkpoint blockade. Collectively, we established a CR-related gene signature that could forecast survival, tumor malignancy and therapeutic response; our findings could help guiding clinical management.

Prognostic and immune-related value of complement C1Q (C1QA, C1QB, and C1QC) in skin cutaneous melanoma

Background: Skin cutaneous melanoma (SKCM) is a common malignancy that is associated with increased morbidity and mortality. Complement C1Q is composed of C1QA, C1QB, and C1QC and is involved in the occurrence and development of many malignant tumours. However, the effect of C1QA, C1QB, and C1QC expression on tumour immunity and prognosis of cutaneous melanoma remains unclear.

Methods: First, we analysed C1QA, C1QB, and C1QC expression levels and prognostic values using Gene Expression Profiling Interactive Analysis (GEPIA) and Tumour Immune Estimation Resource (TIMER) analysis, and further validation was performed using RT-qPCR, The Human Protein Atlas, The Cancer Genome Atlas (TCGA) dataset, and Gene Expression Omnibus dataset. We then performed univariate/multivariate Cox proportional hazard model, clinicopathological correlation, and receiver operating characteristic curve analysis using TCGA dataset and established a nomogram model. Differentially expressed genes associated with C1QA, C1QB, and C1QC in SKCM were identified and analysed using LinkedOmics, TIMER, the Search Tool for the Retrieval of Interacting Genes database, and Metascape and Cytoscape software platforms. We used TIMER, GEPIA, and single-sample gene set enrichment analysis (ssGSEA) to analyse the relationship between the three genes and the level of immune cell infiltration, biomarkers, and checkpoint expression in SKCM. Finally, GSEA was utilized to study the functional pathways of C1QA, C1QB, and C1QC enrichment in SKCM.

Results: The overexpression of C1QA, C1QB, and C1QC provided significant value in the diagnosis of SKCM and has been associated with better overall survival (OS). Multivariate Cox regression analysis indicated that C1QA, C1QB, and C1QC are independent prognostic biomarkers for patients with SKCM. Immune cell infiltration, biomarkers, and checkpoints were positively correlated with the expression of C1QA, C1QB, and C1QC. Furthermore, the results of functional and pathway enrichment analysis showed that immune-related and apoptotic pathways were significantly enriched in the high-expression group of C1QA, C1QB, and C1QC.

Conclusion: We found that C1QA, C1QB, and C1QC can be used as biomarkers for the diagnosis and prognosis of SKCM patients. The upregulated expression levels of these three complement components benefit patients from OS and may increase the effect of immunotherapy. This result may be due to the dual effects of anti-tumour immunity and apoptosis.

Analyzing Prognostic Hub Genes in the Microenvironment of Cutaneous Melanoma by Computer Integrated Bioinformatics

Cutaneous melanoma (CM) is attracting increasing attention due to high mortality. In response to this, we synthetically analyze the CM dataset from the TCGA database and explore microenvironment-related genes that effectively predict patient prognosis. Immune/stromal scores of cases are calculated using the ESTIMATE algorithm and are significantly associated with overall patient survival. Then, differentially expressed genes are identified by comparing the immune score and stromal score, also prognostic genes are subsequently screened. Functional analysis shows that these genes are enriched in different activities of immune system. Moreover, 19 prognosis-related hub genes are extracted from the protein-protein interaction network, of which four unreported genes (IL7R, FLT3, C1QC, and HLA-DRB5) are chosen for validation. A significant negative relationship is found between the expression levels of the 4 genes and pathological stages, notably T grade. Furthermore, the K-M plots and TIMER results show that these genes have favorable value for CM prognosis. In conclusion, these results give a novel insight into CM and identify IL7R, FLT3, C1QC, and HLA-DRB5 as crucial roles for the diagnosis and treatment of CM.

IRF4-activated TEX41 promotes the malignant behaviors of melanoma cells by targeting miR-103a-3p/C1QB axis

BACKGROUND

Malignant melanoma is an aggressive skin cancer and a tumor of melanocytic origin. Recent studies have suggested that long non-coding RNAs (lncRNAs) play crucial regulatory roles in multiple malignancies, including melanoma. Testis expressed 41 (TEX41) is a relatively new lncRNA whose mechanism in melanoma remains vague.

AIMS

This study aimed to explore the role and specific mechanism of TEX41 in melanoma.

METHODS

The expression of genes involved in this study was determined by qRT-PCR. Functional assays were conducted to analyze the role of relevant genes in melanoma cells. The interaction between TEX41 promoter and IRF4 as well as the relationship among TEX41, miR-103a-3p and C1QB was verified by mechanism assays.

RESULTS

IRF4 up-regulated TEX41 at the transcriptional level in melanoma cells. TEX41 knockdown hindered melanoma cell proliferation, migration and invasion while promoting cell apoptosis. TEX41 bound to miR-103a-3p and regulated C1QB. The suppressive impact of TEX41 depletion on melanoma cell malignant behaviors could be counteracted by miR-103a-3p inhibition or C1QB overexpression. Moreover, IRF4 could facilitate melanoma cell growth via up-regulating C1QB.

CONCLUSIONS

IRF4-activated TEX41 sequestered miR-103a-3p and modulated C1QB to promote melanoma cell malignant behaviors, for which TEX41 might be regarded as a potential therapeutic target for melanoma.

Emerging Roles of Pleckstrin-2 Beyond Cell Spreading

Pleckstrin-2 is a member of pleckstrin family with well-defined structural features that was first identified in 1999. Over the past 20 years, our understanding of PLEK2 biology has been limited to cell spreading. Recently, increasing evidences support that PLEK2 plays important roles in other cellular events beyond cell spreading, such as erythropoiesis, tumorigenesis and metastasis. It serves as a potential diagnostic and prognostic biomarker as well as an attractive target for the treatment of cancers. Herein, we summary the protein structure and molecular interactions of pleckstrin-2, with an emphasis on its regulatory roles in tumorigenesis.

Pleckstrin 2 is a potential drug target for colorectal carcinoma with activation of APC/β‑catenin

The tumor suppressor gene adenomatous polyposis coli (APC) is frequently inactivated or absent in colorectal carcinoma (CRC). Loss-of-function of APC promotes the expression of β-catenin, which is critical for CRC development. Since β-catenin acts as an important transcription factor, blockage of β-catenin may have side effects, including impairment of tissue homeostasis and regeneration, thus limiting the application of β-catenin inhibitors for the treatment of patients with CRC. Therefore, identifying a novel substrate of APC/β-catenin may provide essential clues to develop effective drugs. Small interfering RNA technology and lentivirus-mediated overexpression were performed for knockdown and overexpression of pleckstrin 2 (PLEK2) in CRC cells. Cell Counting Kit-8 and colony formation assays, and cell cycle analysis and cell apoptosis detection were used to detect the capacity of cell proliferation, cell cycle distribution and apoptosis. The present study demonstrated that the APC/β-catenin signaling cascade transcriptionally activated PLEK2 in CRC cells. PLEK2 expression was markedly increased in CRC tissues. There was an inverse correlation between APC and PLEK2 expression in patients with CRC. In vitro, overexpression of PLEK2 increased the proliferation of CRC cells. Opposite results were observed in the cells with knockdown of PLEK2. Furthermore, PLEK2 promoted cell cycle progression and suppressed apoptosis. In summary, upregulation of PLEK2 contributed to CRC proliferation and colony formation activated by the APC/β-catenin signal pathway. Targeting PLEK2 may be important for the treatment of patients with CRC with activation of the APC/β-catenin signaling pathway.

TGF-β-induced PLEK2 promotes metastasis and chemoresistance in oesophageal squamous cell carcinoma by regulating LCN2

Oesophageal squamous cell carcinoma (ESCC) has a relatively unfavourable prognosis due to metastasis and chemoresistance. Our previous research established a comprehensive ESCC database (GSE53625). After analysing data from TCGA database and GSE53625, we found that PLEK2 predicted poor prognosis in ESCC. Moreover, PLEK2 expression was also related to the overall survival of ESCC patients undergoing chemotherapy. Repression of PLEK2 decreased the proliferation, migration, invasion and chemoresistance of ESCC cells in vitro and decreased tumorigenicity and distant metastasis in vivo. Mechanistically, luciferase reporter assay and chromatin immunoprecipitation assay suggested that TGF-β stimulated the process that Smad2/3 binds to the promoter sequences of PLEK2 and induced its expression. RNA-seq suggested LCN2 might a key molecular regulated by PLEK2. LCN2 overexpression in PLEK2 knockdown ESCC cells reversed the effects of decreased migration and invasion. In addition, TGF-β induced the expression of LCN2, but the effect disappeared when PLEK2 was knockdown. Moreover, AKT was phosphorylated in all regulatory processes. This study detected the major role of PLEK2 in driving metastasis and chemoresistance in ESCC by regulating LCN2, which indicates the potential use of PLEK2 as a biomarker to predict prognosis and as a therapeutic target for ESCC.

Anti-melanoma effects of concomitant inhibition of SIRT1 and SIRT3 in BrafV600E/PtenNULL mice

Novel therapeutic strategies are required for the effective and lasting treatment of metastatic melanoma, one of the deadliest skin malignancies. In this study, we determined the anti-melanoma efficacy of 4'-bromo-resveratrol (4'-BR), which is a small molecule dual inhibitor of SIRT1 and SIRT3 in a Braf^V600E/Pten^NULL mouse model that recapitulates human disease, including metastases. Tumors were induced by topical application of 4-hydroxy-tamoxifen on shaved backs of 10-week-old mice, and the effects of 4'-BR (5-30 mg/kg b.wt.; intraperitoneally; 3d/week for 5 weeks) were assessed on melanoma development and progression. We found that 4'-BR at a dose of 30 mg/kg significantly reduced size and volume of primary melanoma tumors, as well as lung metastasis, with no adverse effects. Further, mechanistic studies on tumors showed significant modulation in markers of proliferation, survival and melanoma progression. As SIRT1 and SIRT3 are linked to immunomodulation, we performed differential gene expression analysis via NanoString PanCancer Immune Profiling panel (770 genes). Our data demonstrated that 4'-BR significantly downregulated genes related to metastasis-promotion, chemokine/cytokine-regulation, and innate/adaptive immune functions. Overall, inhibition of SIRT1 and SIRT3 by 4'-BR is a promising anti-melanoma therapy with anti-metastatic and immunomodulatory activities warranting further detailed studies, including clinical investigations.

Eight-year longitudinal study of whole blood gene expression profiles in individuals undergoing long-term medical follow-up

Blood circulates throughout the body via the peripheral tissues, contributes to host homeostasis and maintains normal physiological functions, in addition to responding to lesions. Previously, we revealed that gene expression analysis of peripheral blood cells is a useful approach for assessing diseases such as diabetes mellitus and cancer because the altered gene expression profiles of peripheral blood cells can reflect the presence and state of diseases. However, no chronological assessment of whole gene expression profiles has been conducted. In the present study, we collected whole blood RNA from 61 individuals (average age at registration, 50 years) every 4 years for 8 years and analyzed gene expression profiles using a complementary DNA microarray to examine whether these profiles were stable or changed over time. We found that the genes with very stable expression were related mostly to immune system pathways, including antigen cell presentation and interferon-related signaling. Genes whose expression was altered over the 8-year study period were principally involved in cellular machinery pathways, including development, signal transduction, cell cycle, apoptosis, and survival. Thus, this chronological examination study showed that the gene expression profiles of whole blood can reveal unmanifested physiological changes.

Pleckstrin-2 as a Prognostic Factor and Mediator of Gastric Cancer Progression

Pleckstrin-2 (PLEK2) is a crucial mediator of cytoskeletal reorganization. However, the potential roles of PLEK2 in gastric cancer are still unknown. PLEK2 expression in gastric cancer was examined by western blotting and real-time PCR. Survival analysis was utilized to test the clinical impacts of the levels of PLEK2 in gastric cancer patients. In vitro and in vivo studies were used to estimate the potential roles played by PLEK2 in modulating gastric cancer proliferation, self-renewal, and tumourigenicity. Bioinformatics approaches were used to monitor the effect of PLEK2 on epithelial-mesenchymal transition (EMT) signalling pathways. PLEK2 expression was significantly upregulated in gastric cancer as compared with nontumour samples. Kaplan-Meier plotter analysis revealed that gastric cancer patients with higher PLEK2 levels had substantially poorer overall survival compared with gastric cancer patients with lower PLEK2 levels. The upregulation or downregulation of PLEK2 in gastric cancer cell lines effectively enhanced or inhibited cell proliferation and proinvasive behaviour, respectively. Additionally, we also found that PLEK2 enhanced EMT through downregulating E-cadherin expression and upregulating Vimentin expression. Our findings demonstrated that PLEK2 plays a potential role in gastric cancer and may be a novel therapeutic target for gastric cancer.

Pancreatic cancer is marked by complement-high blood monocytes and tumor-associated macrophages

Pancreatic ductal adenocarcinoma (PDA) is accompanied by reprogramming of the local microenvironment, but changes at distal sites are poorly understood. We implanted biomaterial scaffolds, which act as an artificial premetastatic niche, into immunocompetent tumor-bearing and control mice, and identified a unique tumor-specific gene expression signature that includes high expression of C1qa, C1qb, Trem2, and Chil3 Single-cell RNA sequencing mapped these genes to two distinct macrophage populations in the scaffolds, one marked by elevated C1qa, C1qb, and Trem2, the other with high Chil3, Ly6c2 and Plac8 In mice, expression of these genes in the corresponding populations was elevated in tumor-associated macrophages compared with macrophages in the normal pancreas. We then analyzed single-cell RNA sequencing from patient samples, and determined expression of C1QA, C1QB, and TREM2 is elevated in human macrophages in primary tumors and liver metastases. Single-cell sequencing analysis of patient blood revealed a substantial enrichment of the same gene signature in monocytes. Taken together, our study identifies two distinct tumor-associated macrophage and monocyte populations that reflects systemic immune changes in pancreatic ductal adenocarcinoma patients.

PLEK2 promotes osteosarcoma tumorigenesis and metastasis by activating the PI3K/AKT signaling pathway

Increasing evidence suggest that pleckstrin-2 (PLEK2) acts as an oncogene in several malignancies. The present study aimed to investigate the effects of PLEK2 on osteosarcoma (OS) tumorigenesis and metastasis. PLEK2 expression in OS was analyzed via bioinformatics, reverse transcription-quantitative PCR, western blot and immunohistochemistry analyses. The Cell Counting Kit-8 (CCK-8), colony formation and EdU assays were performed to assess the role of PLEK2 in OS cell proliferation. The pro-metastatic effects of PLEK2 were assessed via the Transwell and wound healing assays. In addition, the PLEK2 downstream pathway was analyzed via bioinformatics analysis and verified via western blot analysis. The results demonstrated that PLEK2 expression was upregulated in both OS cell lines and specimens. The results of the CCK-8, colony formation and EdU assays demonstrated that PLEK2 promoted OS cell proliferation in vitro. The in vivo experiments further demonstrated that PLEK2 knockdown significantly suppressed OS growth. In addition, the Transwell and wound healing assays indicated that PLEK2 promoted OS invasiveness in vitro, which was induced by the activation of the epithelial-to-mesenchymal transition process. Bioinformatics analysis revealed that PLEK2 can activate the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) pathway, which was verified via western blot analysis. Taken together, the results of the present study suggest that PLEK2 may play a tumor-promoting role in OS via the PI3K/AKT signaling pathway.

Identification of Hub Genes to Regulate Breast Cancer Spinal Metastases by Bioinformatics Analyses

Breast cancer (BC) had been one of the deadliest types of cancers in women worldwide. More than 65% of advanced-stage BC patients were identified to have bone metastasis. However, the molecular mechanisms involved in the BC spinal metastases remained largely unclear. This study screened dysregulated genes in the progression of BC spinal metastases by analyzing GSE22358. Moreover, we constructed PPI networks to identify key regulators in this progression. Bioinformatics analysis showed that these key regulators were involved in regulating the metabolic process, cell proliferation, Toll-like receptor and RIG-I-like receptor signaling, and mRNA surveillance. Furthermore, our analysis revealed that key regulators, including C1QB, CEP55, HIST1H2BO, IFI6, KIAA0101, PBK, SPAG5, SPP1, DCN, FZD7, KRT5, and TGFBR3, were correlated to the OS time in BC patients. In addition, we analyzed TCGA database to further confirm the expression levels of these hub genes in breast cancer. Our results showed that these regulators were significantly differentially expressed in breast cancer, which were consistent with GSE22358 dataset analysis. Furthermore, our analysis demonstrated that CEP55 was remarkably upregulated in the advanced stage of breast cancer compared to the stage I breast cancer sample and was significantly upregulated in triple-negative breast cancers (TNBC) compared to other types of breast cancers, including luminal and HER2-positive cancers, demonstrating CEP55 may have a regulatory role in TNBC. Finally, our results showed that CEP55 was the most highly expressed in Basal-like 1 TNBC and Basal-like 2 TNBC samples but the most lowly expressed in mesenchymal stem-like TNBC samples. Although more studies are still needed to understand the functions of key regulators in BC, this study provides useful information to understand the mechanisms underlying BC spinal metastases.

microRNA-873 inhibits self-renewal and proliferation of pancreatic cancer stem cells through pleckstrin-2-dependent PI3K/AKT pathway

Recent studies have emphasized microRNAs (miRs) as crucial regulators in the occurrence and development of pancreatic cancer that continues to be one of the deadliest malignancies with few effective therapies. The study aimed to investigate the functional role of miR-873 and its associated mechanism to unravel the biological characteristics of pancreatic cancer stem cells in tumor growth. The expression patterns of pleckstrin-2 (PLEK2) and miR-873 were detected in the pancreatic cancer tissues. Then to further investigate specific role of miR-873, the pancreatic cancer stem cells were treated with miR-873 mimic, PLEK2, small interfering RNA against PLEK2, LY294002 (inhibitor of phosphatidylinositol 3-kinase/protein kinase B [PI3K/AKT] pathway) to detect the relative gene expression as well as their effects on cell self-renewal, proliferation and apoptosis. Finally, the tumor formation in nude mice was measured to verify the preceding results in vivo. Pancreatic cancer tissues exhibited a decline of miR-873 expression and an enhancement of PLEK2 expression. miR-873 targeted PLEK2 and downregulated its expression, leading to inhibition of PI3K/AKT pathway. Overexpressed miR-873 or silenced PLEK2 inhibited the self-renewal and proliferation while promoting the apoptosis of pancreatic cancer stem cells. Tumor formation was inhibited by overexpressed miR-873 or silenced PLEK2 in nude mice. Overall, miR-873 can suppress the self-renewal and proliferation of pancreatic cancer stem cells by blocking PLEK2-dependent PI3K/AKT pathway. Hence, this study contributes to understanding the role of miR-873 in pancreatic cancer stem cells and its underlying molecular mechanisms to aid in the development of effective pancreatic cancer therapeutics.

Identification of TYROBP and FCER1G as Key Genes with Prognostic Value in Clear Cell Renal Cell Carcinoma by Bioinformatics Analysis

The involvement of aberrantly expressed genes in the pathogenesis and progression of various human malignancies has been widely reported, including clear cell renal cell carcinoma (ccRCC). This study aimed to identify potential crucial genes in ccRCC and further investigate the role of these genes in ccRCC prognosis. Three gene expression profiles (GSE3, GSE6344 and GSE53000) were downloaded from GEO database. GEO2R was performed to identify the differentially expressed genes (DEGs) between ccRCC and normal samples. GO analysis and KEGG pathway enrichment analysis were applied for the function analysis. The DEGs were mapped into the PPI network, then the hub genes were identified and verified using the ONCOMINE database. Kaplan-Meier plotter was used to evaluate of the prognostic value of the identified hub genes. A total of 113 DEGs were identified from the three gene expression profiles, including 64 up-regulated genes and 69 down-regulated genes. DEGs were observed to be enriched in biological processes related to the progress and pathogenesis of human cancers. According to PPI network, 5 hub genes were collected, including TYROBP, C1QB, ITGB2, CD53 and FCER1G. Among them, CD53 was newly identified, and Kaplan-Meier survival curves suggested that high expression of CD53 was significantly associated with poor survival in ccRCC patients (log-rank P < 0.01). The present results may provide new insight into the understanding of molecular mechanisms and the clinical prognosis of ccRCC.

PLEK2 Gene Upregulation Might Independently Predict Shorter Progression-Free Survival in Lung Adenocarcinoma

Objective:

This study aimed to explore PLEK2 expression profile, its prognostic value, and the potential genomic alterations associated with its dysregulation in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC).

Materials and methods:

Data from The Cancer Genome Atlas (TCGA), The Genotype-Tissue Expression (GTEx), and Kaplan-Meier plotter were used in combination for bioinformatic analysis.

Results:

PLEK2 mRNA was significantly upregulated in both LUAD and LUSC compared with their respective normal controls. PLEK2 upregulation showed independent prognostic value in progression-free survival (PFS) (HR: 1.169, 95%CI: 1.033 -1.322, p = 0.014). PLEK2 mRNA expression was positively correlated with invasion, cell cycle, DNA damage, and DNA repair of LUAD cells at the single-cell level. Genomic analysis showed that gene-level amplification might not directly lead to increased PLEK2 expression. Methylation profile analysis found 4 CpG sites (cg12199376, cg14437634, cg17641252, and cg06724236) had at least a weakly negative correlation with PLEK2 expression, among which cg12199376, cg14437634 and cg17641252 locate around the first exon of the gene.

Conclusions:

Increased PLEK2 expression might be a specific prognostic biomarker of poor PFS in LUAD patients. Its expression had significant positive correlations with invasion, cell cycle, DNA damage, and DNA repair of LUAD cells at the single-cell level. Promoter hypomethylation might be a potential mechanism leading to its upregulation.

Interleukin-37 is highly expressed in regulatory T cells of melanoma patients and enhanced by melanoma cell secretome

Immune suppression is one of the 10 hallmarks of cancer. Interleukin-37 (IL-37), a member of the IL-1 family, inhibits both innate and adaptive immunity, and has been shown to modulate immune responses in various disease conditions. Yet, IL-37 has rarely been investigated in cancer patients, and its biological role in cancer remains to be elucidated. In this study, we investigated the gene expression of IL-37 in age- and sex-matched blood samples of healthy individuals and melanoma patients, and demonstrated upregulation of IL-37 messenger RNA (mRNA) in the blood samples of melanoma patients. By further analyzing immune cell subsets responsible for the upregulated IL-37 expression, we discovered that IL-37 mRNA was highly expressed in T cells and granulocytes, with the highest expression in regulatory T (Treg ) cells in healthy individuals, and that IL-37 mRNA was upregulated in lymphocytes (T, B, and natural killer cells) in melanoma patient blood. Among all cell subsets, Treg cells from melanoma patients exhibited the highest IL-37 gene expression levels. We provided evidence that melanoma-conditioned media induces IL-37 mRNA and protein expression in multiple lymphocyte populations, particularly in Treg cells. We further confirmed that the IL-1-mediated secretome from human melanoma cells, specifically transforming growth factor-β, induces IL-37 mRNA expression in human Treg cells. Our results suggest a potential immunosuppressive role for IL-1 and IL-37 in melanoma tumorigenesis. Highly elevated IL-37 in specific lymphocyte populations could serve as a biomarker for tumor-induced immunosuppression.

PLEK2 promotes gallbladder cancer invasion and metastasis through EGFR/CCL2 pathway

BACKGROUND

Gallbladder cancer (GBC) is an extremely malignant tumor with a high mortality rate. Little is known about its invasion and metastasis mechanism so far.

METHODS

To identify the driver genes in GBC metastasis, we performed a mRNA microarray of metastatic GBC and paired non-tumor samples, and found PLEK2 was markedly upregulated in GBC tissues. Next, the expression of PLEK2 in GBC were examined in a larger cohort of patients by qRT-PCR, western blot and IHC staining. The clinicopathologic correlation of PLEK2 was determined by statistical analyses. The biological involvement of PLEK2 in GBC metastasis and the underlying mechanisms were investigated.

RESULTS

In this study, we found that PLEK2 had higher expression in GBC tumor tissues compared to non-cancerous adjacent tissues and cholecystolithiasis tissues. The clinicopathologic analyses showed PLEK2 expression was positively correlated with tumor TNM stage, distant metastasis and PLEK2 was an independent predictor of overall survival (OS) in GBC patients. The cellular function assays showed PLEK2 promoted GBC cells migration, invasion and liver metastasis in mouse model via the regulation of epithelial-mesenchymal transition (EMT) process. Our mass spectrum and co-immunoprecipitation (co-IP) assays demonstrated that PLEK2 could interact with the kinase domain of EGFR and suppress EGFR ubiquitination mediated by c-CBL, leading to constitutive activation of EGFR signaling. Furthermore, RNA-sequencing and qRT-PCR results demonstrated chemokine (C-C motif) ligand 2 (CCL2), a target gene downstream of PLEK2/EGFR signaling, mediated the motility-promoting function of PLEK2.

CONCLUSIONS

On the basis of these collective data, we propose that PLEK2 promotes the invasion and metastasis of GBC by EGFR/CCL2 pathway and PLEK2 can serve as a potential therapeutic target for GBC treatment.

Comparative analysis of the blood transcriptomes between wolves and dogs

Dogs were domesticated by human and originated from wolves. Their evolutionary relationships have attracted much scientific interest due to their genetic affinity but different habitats. To identify the differences between dogs and wolves associated with domestication, we analysed the blood transcriptomes of wolves and dogs by RNA-Seq. We obtained a total of 30.87 Gb of raw reads from two dogs and three wolves using RNA-Seq technology. Comparisons of the wolf and dog transcriptomes revealed 524 genes differentially expressed genes between them. We found that some genes related to immune function (DCK, ICAM4, GAPDH and BSG) and aerobic capacity (HBA1, HBA2 and HBB) were more highly expressed in the wolf. Six differentially expressed genes related to the innate immune response (CCL23, TRIM10, DUSP10, RAB27A, CLEC5A and GCH1) were found in the wolf by a Gene Ontology enrichment analysis. Immune system development was also enriched only in the wolf group. The ALAS2, HMBS and FECH genes, shown to be enriched by the Kyoto Encyclopedia of Genes and Genomes analysis, were associated with the higher aerobic capacity and hypoxia endurance of the wolf. The results suggest that the wolf might have greater resistance to pathogens, hypoxia endurance and aerobic capacity than dogs do.

Generation and characterization of the blood transcriptome of Macaca thibetana and comparative analysis with M. mulatta

Transcriptome profiles provide a large transcript sequence data set for genomic study, particularly in organisms that have no accurate genome data published. The Tibetan macaque (Macaca thibetana) is commonly considered to be an endemic species to China and an important animal in biomedical research in the present day. In the present study, we report the de novo assembly and characterization of the blood transcriptome of the Tibetan macaque from three individuals, and we also sequenced the blood transcriptome of the rhesus macaque (Macaca mulatta) for comparison. Using RNA-seq technology, 138 million sequencing reads of the M. thibetana transcriptome were generated. The assembly included 327 871 transcripts with an N50 of 1571 bp. According to the sequence similarity search, 80 317 (24.5%) transcripts were annotated in the nr protein database. All transcripts from M. thibetana and M. mulatta were functionally classified and compared using GO and KEGG analyses. The two transcriptomes were different in the GO term of nutrient reservoir activity, and in the KEGG subcategories of signaling molecules and interaction, infectious diseases, cell growth and death, and immune system. The transcriptomes in this study would provide a valuable resource for future functional and comparative genomic studies, and even for biological studies of this non-human primate.

Blood transcriptomics of captive forest musk deer (Moschus berezovskii) and possible associations with the immune response to abscesses

Forest musk deer (Moschus berezovskii; FMD) are both economically valuable and highly endangered. A problem for FMD captive breeding programs has been the susceptibility of FMD to abscesses. To investigate the mechanisms of abscess development in FMD, the blood transcriptomes of three purulent and three healthy individuals were generated. A total of ~39.68 Gb bases were generated using Illumina HiSeq 4000 sequencing technology and 77,752 unigenes were identified after assembling. All the unigenes were annotated, with 63,531 (81.71%) mapping to at least one database. Based on these functional annotations, 45,798 coding sequences (CDS) were detected, along with 12,697 simple sequence repeats (SSRs) and 65,536 single nucleotide polymorphisms (SNPs). A total of 113 unigenes were found to be differentially expressed between healthy and purulent individuals. Functional annotation indicated that most of these differentially expressed genes were involved in the regulation of immune system processes, particularly those associated with parasitic and bacterial infection pathways.

Whole-blood RNA transcript-based models can predict clinical response in two large independent clinical studies of patients with advanced melanoma treated with the checkpoint inhibitor, tremelimumab

Background

Tremelimumab is an antibody that blocks CTLA-4 and demonstrates clinical efficacy in a subset of advanced melanoma patients. An unmet clinical need exists for blood-based response-predictive gene signatures to facilitate clinically effective and cost-efficient use of such immunotherapeutic interventions.

Methods

Peripheral blood samples were collected in PAXgene® tubes from 210 treatment-naïve melanoma patients receiving tremelimumab in a worldwide, multicenter phase III study (discovery dataset). A central panel of radiologists determined objective response using RECIST criteria. Gene expression for 169 mRNA transcripts was measured using quantitative PCR. A 15-gene pre-treatment response-predictive classifier model was identified. An independent population (N = 150) of refractory melanoma patients receiving tremelimumab after chemotherapy enrolled in a worldwide phase II study (validation dataset). The classifier model, using the same genes, coefficients and constants for objective response and one-year survival after treatment, was applied to the validation dataset.

Results

A 15-gene pre-treatment classifier model (containing ADAM17, CDK2, CDKN2A, DPP4, ERBB2, HLA-DRA, ICOS, ITGA4, LARGE, MYC, NAB2, NRAS, RHOC, TGFB1, and TIMP1) achieved an area under the curve (AUC) of 0.86 (95% confidence interval 0.81 to 0.91, p < 0.0001) for objective response and 0.6 (95% confidence interval 0.54 to 0.67, p = 0.0066) for one-year survival in the discovery set. This model was validated in the validation set with AUCs of 0.62 (95% confidence interval 0.54 to 0.70 p = 0.0455) for objective response and 0.68 for one-year survival (95% confidence interval 0.59 to 0.75 p = 0.0002).

Conclusions

To our knowledge, this is the largest blood-based biomarker study of a checkpoint inhibitor, tremelimumab, which demonstrates a validated pre-treatment mRNA classifier model that predicts clinical response. The data suggest that the model captures a biological signature representative of genes needed for a robust anti-cancer immune response. It also identifies non-responders to tremelimumab at baseline prior to treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s40425-017-0272-z) contains supplementary material, which is available to authorized users.

Population effect model identifies gene expression predictors of survival outcomes in lung adenocarcinoma for both Caucasian and Asian patients

BACKGROUND

We analyzed and integrated transcriptome data from two large studies of lung adenocarcinomas on distinct populations. Our goal was to investigate the variable gene expression alterations between paired tumor-normal tissues and prospectively identify those alterations that can reliably predict lung disease related outcomes across populations.

METHODS

We developed a mixed model that combined the paired tumor-normal RNA-seq from two populations. Alterations in gene expression common to both populations were detected and validated in two independent DNA microarray datasets. A 10-gene prognosis signature was developed through a l1 penalized regression approach and its prognostic value was evaluated in a third independent microarray cohort.

RESULTS

Deregulation of apoptosis pathways and increased expression of cell cycle pathways were identified in tumors of both Caucasian and Asian lung adenocarcinoma patients. We demonstrate that a 10-gene biomarker panel can predict prognosis of lung adenocarcinoma in both Caucasians and Asians. Compared to low risk groups, high risk groups showed significantly shorter overall survival time (Caucasian patients data: HR = 3.63, p-value = 0.007; Asian patients data: HR = 3.25, p-value = 0.001).

CONCLUSIONS

This study uses a statistical framework to detect DEGs between paired tumor and normal tissues that considers variances among patients and ethnicities, which will aid in understanding the common genes and signalling pathways with the largest effect sizes in ethnically diverse cohorts. We propose multifunctional markers for distinguishing tumor from normal tissue and prognosis for both populations studied.

Integrated analysis identified genes associated with a favorable prognosis in oligodendrogliomas

Oligodendrogliomas (ODs) are the second most common malignant brain tumor and exhibit characteristic co-deletion of chromosomal arms 1p and 19q (co-deletion 1p/19q), which is associated with down-regulation of tumor suppressors. However, co-deletion 1p/19q indicates a favorable prognosis that cannot be explained by the down-regulation of tumor suppressors. In the present study, we determined that co-deletion 1p/19q was associated with reduced Ki-67 protein level based on analysis of 354 ODs. To identify genes associated with reduced Ki-67 and a favorable prognosis of codeletion 1p/19q, we analyzed 96 ODs with RNA-sequencing and 136 ODs and 4 normal brain tissue samples with RNA microarrays. We thus identified seven genes within chromosomal arms 1p/19q with significantly reduced expression in samples with co-deletion of 1p/19q compared to samples with intact 1p/19q. A significant positive correlation was observed between these candidate genes and Ki-67 expression based on analysis of mRNA expression in 305 gliomas and 5 normal brain tissue samples. Survival analysis confirmed the prognostic value of these candidate genes. This finding suggests that these genes within chromosomal arms 1p/19q are associated with low Ki-67 and a favorable prognosis in ODs with co-deletion 1p/19q and provides novel therapeutic targets.

Diverse Functions of Plasma PAF-AH in Tumorigenesis

This chapter is focused on the role of the plasma form of platelet-activating factor-acetylhydrolase (PAF-AH), heretofore referred to as PAF-AH, in tumorigenic responses. Biochemical and other properties of this enzyme were discussed in detail in chapter "Plasma PAF-AH (PLA2G7): Biochemical Properties, Association with LDLs and HDLs, and Regulation of Expression" by Stafforini and in other chapters. Although phospholipases tend not to be drivers of tumorigenesis themselves, these enzymes and the lipid mediators whose levels they regulate interact with a variety of oncogenes and tumor suppressors [1]. Like other phospholipases, the functions of PAF-AH in cancer likely are related to its ability to regulate the levels of lipid mediators that participate in cellular processes related to initial tumorigenic events (e.g., proliferation, growth, inflammation) and/or spreading of the disease (e.g., matrix metalloproteinase secretion, actin cytoskeleton reorganization, migration, and angiogenesis) [1]. The importance of substrates and products of PAF-AH on key cellular functions has been evaluated in cell-based analyses which revealed that these metabolites can have pro- and antitumorigenic functions. Studies in genetically engineered mice lacking PAF-AH expression and genetic manipulation of PAF-AH levels in cancer cells demonstrated diverse functions of the protein in models of melanoma, prostate cancer, colon cancer, and others. The following sections highlight lessons learned from studies in cell lines and in mouse models regarding the diversity of functions of PAF-AH in cancer, and the potential of PAFAH transcripts, protein, and/or activity levels to become cancer biomarkers and therapeutic targets.

DC immunotherapy in HIV-1 infection induces a major blood transcriptome shift

OBJECTIVE

This study aimed to evaluate the effect of dendritic cell (DC) vaccination against HIV-1 on host gene expression profiles.

DESIGN

Longitudinal PBMC samples were collected from participants of the DC-TRN trial for immunotherapy against HIV. Microarray-assisted gene expression profiling was performed to evaluate the effects of vaccination and subsequent interruption of antiretroviral therapy on host genome expression. Data from the DC-TRN trial were compared with results from other vaccination trials.

METHODS

We used Affymetrix GeneChips for microarray gene expression analysis. Data were analyzed by principal component analysis and differential gene expression was assessed using linear modeling. Gene ontology enrichment and gene set analysis were used to characterize differentially expressed genes. Transcriptome analysis included comparison with PBMCs obtained from DC-vaccinated melanoma patients and of healthy individuals who received seasonal influenza vaccination.

RESULTS

DC-TRN immunotherapy in HIV-infected individuals resulted in a major shift in the transcriptome. Longitudinal analysis demonstrated that changes in the transcriptome sustained also during interruption of antiretroviral therapy. After DC-vaccination, the transcriptome was enriched for cellular immunity associated genes that were also induced in healthy adults who received live attenuated influenza virus vaccination. These beneficial responses were accompanied by detrimental signals of general immune activation.

CONCLUSIONS

The DC-TRN induced changes in the transcriptome were profound, lasting, and consisted of both protective signals and signatures of inflammation and immune exhaustion, with a net result of decreased viral load, without clinical benefit. Thus transcriptome analysis provides useful information, dissecting both positive and negative effects, for the evaluation of safety and efficacy of immunotherapeutic strategies.

Gene expression profiling of immunomagnetically separated cells directly from stabilized whole blood for multicenter clinical trials

Background

Clinically useful biomarkers for patient stratification and monitoring of disease progression and drug response are in big demand in drug development and for addressing potential safety concerns. Many diseases influence the frequency and phenotype of cells found in the peripheral blood and the transcriptome of blood cells. Changes in cell type composition influence whole blood gene expression analysis results and thus the discovery of true transcript level changes remains a challenge. We propose a robust and reproducible procedure, which includes whole transcriptome gene expression profiling of major subsets of immune cell cells directly sorted from whole blood.

Methods

Target cells were enriched using magnetic microbeads and an autoMACS® Pro Separator (Miltenyi Biotec). Flow cytometric analysis for purity was performed before and after magnetic cell sorting. Total RNA was hybridized on HGU133 Plus 2.0 expression microarrays (Affymetrix, USA). CEL files signal intensity values were condensed using RMA and a custom CDF file (EntrezGene-based).

Results

Positive selection by use of MACS® Technology coupled to transcriptomics was assessed for eight different peripheral blood cell types, CD14+ monocytes, CD3+, CD4+, or CD8+ T cells, CD15+ granulocytes, CD19+ B cells, CD56+ NK cells, and CD45+ pan leukocytes. RNA quality from enriched cells was above a RIN of eight. GeneChip analysis confirmed cell type specific transcriptome profiles. Storing whole blood collected in an EDTA Vacutainer® tube at 4°C followed by MACS does not activate sorted cells. Gene expression analysis supports cell enrichment measurements by MACS.

Conclusions

The proposed workflow generates reproducible cell-type specific transcriptome data which can be translated to clinical settings and used to identify clinically relevant gene expression biomarkers from whole blood samples. This procedure enables the integration of transcriptomics of relevant immune cell subsets sorted directly from whole blood in clinical trial protocols.

Skinomics: past, present and future for diagnostic microarray studies in dermatology

Easily accessible, skin was among the first targets analyzed using 'omics' and dermatology embraced the approaches very early. Microarrays have been used to define disease markers, identify transcriptional changes and even trace the course of treatment. Melanoma and psoriasis have been explored using microarrays. Particularly noteworthy is the multinational mapping of psoriasis susceptibility loci. The transcriptional changes in psoriasis have been identified using hundreds of biopsies. Epidermal keratinocytes have been studied because they respond to UV light, infections, inflammatory and immunomodulating cytokines, toxins and so on. Epidermal differentiation genes are being characterized and are expressed in human epidermal stem cells. Exciting discoveries defining human skin microbiomes have opened a new field of research with great medical potential. Specific to dermatology, the non-invasive skin sampling for microarray studies, using tape stripping, has been developed; it promises to advance dermatology toward 'omics' techniques directly applicable to the personalized medicine of the future.

Blood mRNA expression profiling predicts survival in patients treated with tremelimumab

PURPOSE

Tremelimumab (ticilimumab, Pfizer), is a monoclonal antibody (mAb) targeting cytotoxic T lymphocyte-associated antigen-4 (CTLA-4). Ipilimumab (Yervoy, BMS), another anti-CTLA-4 antibody, is approved by the U.S. Federal Drug Administration (FDA). Biomarkers are needed to identify the subset of patients who will achieve tumor control with CTLA-4 blockade.

EXPERIMENTAL DESIGN

Pretreatment peripheral blood samples from 218 patients with melanoma who were refractory to prior therapy and receiving tremelimumab in a multicenter phase II study were measured for 169 mRNA transcripts using reverse transcription polymerase chain reaction (RT-PCR). A two-class latent model yielded a risk score based on four genes that were highly predictive of survival (P < 0.001). This signature was validated in an independent population of 260 treatment-naïve patients with melanoma enrolled in a multicenter phase III study of tremelimumab.

RESULTS

Median follow-up was 297 days for the training population and 386 days for the test population. Expression levels of the 169 genes were closely correlated across the two populations (r = 0.9939). A four-gene model, including cathepsin D (CTSD), phopholipase A2 group VII (PLA2G7), thioredoxin reductase 1 (TXNRD1), and interleukin 1 receptor-associated kinase 3 (IRAK3), predicted survival in the test population (P = 0.001 by log-rank test). This four-gene model added to the predictive value of clinical predictors (P < 0.0001).

CONCLUSIONS

Expression levels of CTSD, PLA2G7, TXNRD1, and IRAK3 in peripheral blood are predictive of survival in patients with melanoma treated with tremelimumab. Blood mRNA signatures should be further explored to define patient subsets likely to benefit from immunotherapy.

A fast workflow for identification and quantification of proteomes

The current in-depth proteomics makes use of long chromatography gradient to get access to more peptides for protein identification, resulting in covering of as many as 8000 mammalian gene products in 3 days of mass spectrometer running time. Here we report a fast sequencing (Fast-seq) workflow of the use of dual reverse phase high performance liquid chromatography - mass spectrometry (HPLC-MS) with a short gradient to achieve the same proteome coverage in 0.5 day. We adapted this workflow to a quantitative version (Fast quantification, Fast-quan) that was compatible to large-scale protein quantification. We subjected two identical samples to the Fast-quan workflow, which allowed us to systematically evaluate different parameters that impact the sensitivity and accuracy of the workflow. Using the statistics of significant test, we unraveled the existence of substantial falsely quantified differential proteins and estimated correlation of false quantification rate and parameters that are applied in label-free quantification. We optimized the setting of parameters that may substantially minimize the rate of falsely quantified differential proteins, and further applied them on a real biological process. With improved efficiency and throughput, we expect that the Fast-seq/Fast-quan workflow, allowing pair wise comparison of two proteomes in 1 day may make MS available to the masses and impact biomedical research in a positive way.

Comparative proteomics, network analysis and post-translational modification identification reveal differential profiles of plasma Con A-bound glycoprotein biomarkers in gastric cancer

In the study, we used Con A affinity chromatography, 1-D gel electrophoresis, and nano-LC-MS/MS to screen biomarker candidates in plasma samples obtained from 30 patients with gastric cancer and 30 healthy volunteers. First, we pooled plasma samples matched by age and sex. We identified 17 differentially expressed Con A-bound glycoproteins, including 10 upregulated proteins and 7 downregulated proteins; these differences were significant (Student's t-test, p-value<0.05). Furthermore, 2 of the upregulated proteins displayed expression levels that were increased by 2-fold or more in gastric cancer samples when compared with normal control samples. These proteins included leucine-rich alpha-2-glycoprotein (LRG1) and inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3), and the expression levels were validated by Western blot analysis. Pathway and network analysis of the differentially expressed proteins by Ingenuity Pathway Analysis revealed vital canonical pathways involving acute phase response signaling, the complement system, LXR/RXR activation, hematopoiesis from pluripotent stem cells, and primary immunodeficiency signaling. Our results suggest that Con A-bound LRG1 and ITIH3 may not be practically applicable as a robust biomarker for the early detection of gastric cancer. Additionally, three novel PTMs in ITIH3 were identified and include hexose-N-acetyl-hexosamine at asparagine-(41), trimethylation at aspartic acid-(290), and flavin adenine dinucleotide at histidine-(335).

BIOLOGICAL SIGNIFICANCE

Our study was to describe a combinatorial approach of Con A affinity chromatography, 1-D SDS-PAGE, and nano-LC/MS/MS that provides a label-free, comparative glycoproteomic quantification strategy for the investigation of glycoprotein profiles in plasma from gastric cancer patients versus healthy volunteers and to identify glycoprotein biomarkers for the early clinical detection of gastric cancer. Three novel PTMs, HexHexNAc, trimethylation and FAD, in Con A-bound ITIH3 were identified and built in molecular modeling. The aspartic acid-(290) trimethylation site was located in a metal ion-dependent adhesion site (MIDAS motif; (290)-DXSXS…T…D-(313)) that may influence important function for binding protein ligands.

Combined anti-tumor necrosis factor-α therapy and DMARD therapy in rheumatoid arthritis patients reduces inflammatory gene expression in whole blood compared to DMARD therapy alone

Periodic assessment of gene expression for diagnosis and monitoring in rheumatoid arthritis (RA) may provide a readily available and useful method to detect subclinical disease progression and follow responses to therapy with disease modifying anti-rheumatic agents (DMARDs) or anti-TNF-α therapy. We used quantitative real-time PCR to compare peripheral blood gene expression profiles in active (“unstable”) RA patients on DMARDs, stable RA patients on DMARDs, and stable RA patients treated with a combination of a disease-modifying anti-rheumatoid drug (DMARD) and an anti-TNF-α agent (infliximab or etanercept) to healthy human controls. The expression of 48 inflammatory genes were compared between healthy controls (N = 122), unstable DMARD patients (N = 18), stable DMARD patients (N = 26), and stable patients on combination therapy (N = 20). Expression of 13 genes was very low or undetectable in all study groups. Compared to healthy controls, patients with unstable RA on DMARDs exhibited increased expression of 25 genes, stable DMARD patients exhibited increased expression of 14 genes and decreased expression of five genes, and combined therapy patients exhibited increased expression of six genes and decreased expression of 10 genes. These findings demonstrate that active RA is associated with increased expression of circulating inflammatory markers whereas increases in inflammatory gene expression are diminished in patients with stable disease on either DMARD or anti-TNF-α therapy. Furthermore, combination DMARD and anti-TNF-α therapy is associated with greater reductions in circulating inflammatory gene expression compared to DMARD therapy alone. These results suggest that assessment of peripheral blood gene expression may prove useful to monitor disease progression and response to therapy.