A glycolytic mechanism regulating an angiogenic switch in prostate cancer

Revving the engine: PKB/AKT as a key regulator of cellular glucose metabolism

Glucose metabolism is of critical importance for cell growth and proliferation, the disorders of which have been widely implicated in cancer progression. Glucose uptake is achieved differently by normal cells and cancer cells. Even in an aerobic environment, cancer cells tend to undergo metabolism through glycolysis rather than the oxidative phosphorylation pathway. Disordered metabolic syndrome is characterized by elevated levels of metabolites that can cause changes in the tumor microenvironment, thereby promoting tumor recurrence and metastasis. The activation of glycolysis-related proteins and transcription factors is involved in the regulation of cellular glucose metabolism. Changes in glucose metabolism activity are closely related to activation of protein kinase B (PKB/AKT). This review discusses recent findings on the regulation of glucose metabolism by AKT in tumors. Furthermore, the review summarizes the potential importance of AKT in the regulation of each process throughout glucose metabolism to provide a theoretical basis for AKT as a target for cancers.

Regulation of phosphoglycerate kinase 1 and its critical role in cancer

Cells that undergo normal differentiation mainly rely on mitochondrial oxidative phosphorylation to provide energy, but most tumour cells rely on aerobic glycolysis. This phenomenon is called the "Warburg effect". Phosphoglycerate kinase 1 (PGK1) is a key enzyme in aerobic glycolysis. PGK1 is involved in glucose metabolism as well as a variety of biological activities, including angiogenesis, EMT, mediated autophagy initiation, mitochondrial metabolism, DNA replication and repair, and other processes related to tumorigenesis and development. Recently, an increasing number of studies have proven that PGK1 plays an important role in cancer. In this manuscript, we discussed the effects of the structure, function, molecular mechanisms underlying PGK1 regulation on the initiation and progression of cancer. Additionally, PGK1 is associated with chemotherapy resistance and prognosis in tumour patients. This review presents an overview of the different roles played by PGK1 during tumorigenesis, which will help in the design of experimental studies involving PGK1 and enhance the potential for the use of PGK1 as a therapeutic target in cancer. Video Abstract.

Extracellular Pgk1 interacts neural membrane protein enolase-2 to improve the neurite outgrowth of motor neurons

Understanding the molecular interaction between ligand and receptor is important for providing the basis for the development of regenerative drugs. Although it has been reported that extracellular phosphoglycerate kinase 1 (Pgk1) can promote the neurite outgrowth of motoneurons, the Pgk1-interacting neural receptor remains unknown. Here we show that neural membranous Enolase-2 exhibits strong affinity with recombinant Pgk1-Flag, which is also evidently demonstrated by immunoelectron microscopy. The 325th-417th domain of Pgk1 interacts with the 405th-431st domain of Enolase-2, but neither Enolase-1 nor Enolase-3, promoting neurite outgrowth. Combining Pgk1 incubation and Enolase-2 overexpression, we demonstrate a highly significant enhancement of neurite outgrowth of motoneurons through a reduced p-P38-T180/p-Limk1-S323/p-Cofilin signaling. Collectively, extracellular Pgk1 interacts neural membrane receptor Enolase-2 to reduce the P38/Limk1/Cofilin signaling which results in promoting neurite outgrowth. The extracellular Pgk1-specific neural receptor found in this study should provide a material for screening potential small molecule drugs that promote motor nerve regeneration.

PGK1 modulates balance between pro- and anti-inflammatory cytokines by interacting with ITI-H4

Inter-α-trypsin inhibitor heavy chain 4 (ITI-H4) is one of the acute phase proteins and is mainly related with inflammatory diseases such as bacterial bloodstream infection and recurrent pregnancy loss (RPL). In a previous study, ITI-H4 was reported to be cleaved by kallikrein B1 (KLKB1) and its cleaved form induces the imbalance between pro- and anti-inflammatory cytokines. Therefore, in this study, putative substrates of ITI-H4 were isolated by immunoprecipitation and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analysis. Of those, phosphoglycerate kinase 1 (PGK1) was found to be a binding protein of ITI-H4. PGK1 increases the level of ITI-H4 expression and blocks the cleavage of ITI-H4 mediated by KLKB1. It also inhibits pro-inflammatory response by inhibiting the JAK2/STAT3 signaling pathway. Therefore, PGK1, a novel binding partner of ITI-H4, is expected to have cellular functions in the pathogenesis of ITI-H4-related inflammatory diseases.

The role of CXCL12 axis in pancreatic cancer: New biomarkers and potential targets

Introduction

Chemokines are small, secreted peptides involved in the mediation of the immune cell recruitment. Chemokines have been implicated in several diseases including autoimmune diseases, viral infections and also played a critical role in the genesis and development of several malignant tumors. CXCL12 is a homeostatic CXC chemokine involved in the process of proliferation, and tumor spread. Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors, that is still lacking effective therapies and with a dramatically poor prognosis.

Method

We conducted a scientific literature search on Pubmed and Google Scholar including retrospective, prospective studies and reviews focused on the current research elucidating the emerging role of CXCL12 and its receptors CXCR4 - CXCR7 in the pathogenesis of pancreatic cancer.

Results

Considering the mechanism of immunomodulation of the CXCL12-CXCR4-CXCR7 axis, as well as the potential interaction with the microenvironment in the PDAC, several combined therapeutic approaches have been studied and developed, to overcome the "cold" immunological setting of PDAC, like combining CXCL12 axis inhibitors with anti PD-1/PDL1 drugs.

Conclusion

Understanding the role of this chemokine's axis in disease initiation and progression may provide the basis for developing new potential biomarkers as well as therapeutic targets for related pancreatic cancers.

LncRNA NEAT1 facilitates glioma progression via stabilizing PGK1

Background

Long noncoding RNA NEAT1 has been implicated in glioma progression. However, the effect of NEAT1 on glycolysis of glioma cell and the potential mechanism remain unclear.

Methods

In vitro experiments, including CCK-8, colony formation, ECAR, and lactate detection assays were performed to evaluate the effect of NEAT1 on proliferation and glycolysis of glioma cell. RNA pulldown and RIP assays were performed to identify the interaction between NEAT1 and PGK1. Truncated mutation of NEAT1 and PGK1 was used to confirm the specific interactive domains between NEAT1 and PGK1. Animal studies were performed to analyze the effect of NEAT1/PGK1 on glioma progression.

Results

NEAT1 knockdown significantly suppressed the proliferation and glycolysis of glioma cells. NEAT1 could specifically interact with PGK1, which promotes PGK1 stability. Hairpin A of NEAT1 is essential for interaction with M1 domain of PGK1. Depletion of NEAT1 markedly inhibited tumor growth in mice, while PGK1 could reverse this effect. Higher expression of NEAT1 was associated with poor overall survival of GBM patients.

Conclusions

NEAT1 over expression promotes glioma progression through stabilizing PGK1. NEAT1/PGK1 axis is a candidate therapeutic target for glioma treatment.

PGK1 : An Essential Player in Modulating Tumor Metabolism

Phosphoglycerate kinase 1 (PGK1) is the first enzyme in glycolysis to generate a molecule of ATP in the conversion of 1,3-bisphosphoglycerate (1,3-BPG) to 3-phosphoglycerate (3-PG). In addition to the role of glycolysis, PGK-1 acts as a polymerase alpha cofactor protein, with effects on the tricarboxylic acid cycle, DNA replication and repair. Posttranslational modifications such as methylation, phosphorylation, and acetylation have been seen to activate PGK1 in cancer. High levels of intracellular PGK1 are associated with tumorigenesis and progression, and chemoradiotherapy resistance. However, high levels of extracellular PGK1 suppress angiogenesis and subsequently counteract cancer malignancy. Here we have summarized the current knowledge on the mechanisms and effects of PGK1 in various tumor types and evaluated its potential prognostic and therapeutic value in cancer. The data summarized here aims at providing molecular information and new ideas of employing natural products to combat cancer associated with PGK1.

Current Development and Application of Anaerobic Glycolytic Enzymes in Urothelial Cancer

Urothelial cancer is a malignant tumor with metastatic ability and high mortality. Malignant tumors of the urinary system include upper tract urothelial cancer and bladder cancer. In addition to typical genetic alterations and epigenetic modifications, metabolism-related events also occur in urothelial cancer. This metabolic reprogramming includes aberrant expression levels of genes, metabolites, and associated networks and pathways. In this review, we summarize the dysfunctions of glycolytic enzymes in urothelial cancer and discuss the relevant phenotype and signal transduction. Moreover, we describe potential prognostic factors and risks to the survival of clinical cancer patients. More importantly, based on several available databases, we explore relationships between glycolytic enzymes and genetic changes or drug responses in urothelial cancer cells. Current advances in glycolysis-based inhibitors and their combinations are also discussed. Combining all of the evidence, we indicate their potential value for further research in basic science and clinical applications.

LHX9, a p53-binding protein, inhibits the progression of glioma by suppressing glycolysis

PURPOSE

LHX9 methylation has been reported in many tumors, but its functions and related mechanisms in glioma are still unknown and need to be verified.

METHODS

The protein level of LHX9 in glioma tissues was examined using western blotting and immunohistochemistry, and the functions of LHX9 in glioma cell lines were investigated using MTT and colony formation assays. In addition, the interaction between LHX9 and P53 was analyzed by immunoprecipitation, and the roles of LHX9 in cancer metabolism were explored by measuring metabolites.

RESULTS

In this study, we found that the LHX9 expression level was decreased in glioma specimens, and the upregulation of LHX9 expression inhibited the growth of glioma cells in liquid medium and on soft agar. Regarding the molecular mechanism, we found that LHX9 interacted with p53, and downregulation of LHX9 promoted the expression of the glycolysis-related enzyme PGK1 and increased the lactic acid content. By interfering with the expression of LHX9, the tumorigenicity of glioma cells was promoted, an outcome blocked by further interference with PGK1 expression.

CONCLUSION

In summary, the decreased expression of LHX9 in gliomas activates the expression of the glycolysis-related enzyme PGK1, thereby promoting the development of gliomas, suggesting that the LHX9-PGK1 signaling axis can be used as a target for the treatment of glioma.

Neovascularization of engineered tissues for clinical translation: Where we are, where we should be?

One of the key challenges in engineering three-dimensional tissue constructs is the development of a mature microvascular network capable of supplying sufficient oxygen and nutrients to the tissue. Recent angiogenic therapeutic strategies have focused on vascularization of the constructed tissue, and its integration in vitro; these strategies typically combine regenerative cells, growth factors (GFs) with custom-designed biomaterials. However, the field needs to progress in the clinical translation of tissue engineering strategies. The article first presents a detailed description of the steps in neovascularization and the roles of extracellular matrix elements such as GFs in angiogenesis. It then delves into decellularization, cell, and GF-based strategies employed thus far for therapeutic angiogenesis, with a particularly detailed examination of different methods by which GFs are delivered in biomaterial scaffolds. Finally, interdisciplinary approaches involving advancement in biomaterials science and current state of technological development in fabrication techniques are critically evaluated, and a list of remaining challenges is presented that need to be solved for successful translation to the clinics.

Prognostic Impact of CXCR7 and CXCL12 Expression in Patients with Esophageal Adenocarcinoma

BACKGROUND

Chemokines are major regulators of cell trafficking and adhesion. The chemokine CXCL12 and its receptors, CXCR4 and CXCR7, have been reported as biomarkers in various cancers, including esophageal cancer; however, there are few studies in esophageal adenocarcinoma (EAC). In this study, we investigated the relationship between expression of CXCL12, CXCR4, and CXCR7, and prognosis in patients with EAC.

METHODS

This study examined 55 patients with EAC who were treated in Toronto General Hospital from 2001 to 2010. Tissue microarray immunohistochemistry was used to evaluate the expression of CXCL12, CXCR4, and CXCR7. Evaluation of immunohistochemistry was performed by a pathologist without knowledge of patients' information and results were compared with the patients' clinicopathological features and survival.

RESULTS

High CXCR7 expression was significantly associated with lymphatic invasion (present vs absent, P = 0.005) and higher number of lymph node metastases (pN0-1 vs pN2-3, P = 0.0014). Patients with high CXCR7 expression (n = 23) were associated with worse overall (OS) and disease-free survival (DFS) (P = 0.0221, P = 0.0090, respectively), and patients with high CXCL12 (n = 24) tended to have worse OS and DFS (P = 0.1091, P = 0.1477, respectively). High expression of both CXCR7 and CXCL12 was an independent prognostic factor for OS and DFS on multivariate analysis (HR = 0.3, 95% CI: 0.1-0.9, P = 0.0246, HR = 0.3, 95% CI: 0.1-0.8, P = 0.0134, respectively).

CONCLUSIONS

High CXCR7 expression was associated with poor prognosis in patients with EAC, and high expression of CXCR7 with its ligand CXCL12 had a stronger association with prognosis. Further study of this potential biomarker using whole tissue samples and a larger sample size is warranted.

Silencing of PGK1 Promotes Sensitivity to Paclitaxel Treatment by Upregulating XAF1-Mediated Apoptosis in Triple-Negative Breast Cancer

Objective: Triple negative breast cancer (TNBC) is known to have aggressive clinical course and a high risk of recurrence. Given the lack of effective targeted therapy options, paclitaxel-based chemotherapy is still the primary option for TNBC patients. However, patients who fail to achieve a complete response during neoadjuvant chemotherapy may be mainly due to sensitivity and resistance to chemotherapy. Thus, we concentrated the present research on the role of PGK1 in the sensitivity to paclitaxel treatment and the possible underlying mechanisms in TNBC.

Methods: After exposure to paclitaxel, a cell viability analysis was made to investigate the influence of PGK1 silencing on cell death. The effect of PGK1 on apoptosis induced by paclitaxel treatment was examined in vitro by flow cytometry cell apoptosis assays. Western blotting was performed to examine the impact of PGK1 on paclitaxel-induced apoptosis. The correlation of PGK1 with apoptosis-associated protein X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1) was analyzed in 39 specimens by immunohistochemistry analysis.

Results: We observed that silencing PGK1 sensitized triple-negative breast cancer (TNBC) cell lines to paclitaxel treatment as a result of increased drug-induced apoptosis. Furthermore, mechanistic investigations suggested that XAF1 was increased in PGK1-knockdown cells along with the expression of the apoptotic proteins including cleaved caspase-3 and Bax. Immunohistochemistry analysis showed that PGK1 was negatively related to XAF1. Moreover, we found that downregulation of XAF1 reduced paclitaxel-induced apoptosis in PGK1-silenced triple-negative cell lines.

Conclusion: Our results identified PGK1 as a potential biomarker for the treatment of TNBC, and inhibition of PGK1 expression might represent a novel strategy to sensitize TNBC to paclitaxel treatment.

Avian Reovirus P17 Suppresses Angiogenesis by Promoting DPP4 Secretion

Avian reovirus p17 (ARV p17) is a non-structural protein known to activate autophagy, interfere with gene transcription and induce a significant tumor cell growth inhibition in vitro and in vivo. In this study, we show that ARV p17 is capable of exerting potent antiangiogenic properties. The viral protein significantly inhibited the physiological angiogenesis of human endothelial cells (ECs) by affecting migration, capillary-like structure and new vessel formation. ARV p17 was not only able to suppress the EC physiological angiogenesis but also rendered ECs insensitive to two different potent proangiogenic inducers, such as VEGF-A and FGF-2 in the three-dimensional (3D) Matrigel and spheroid assay. ARV p17 was found to exert its antiangiogenic activity by upregulating transcription and release of the well-known tumor suppressor molecule dipeptidyl peptidase 4 (DPP4). The ability of ARV p17 to impact on angiogenesis is completely new and highlights the “two compartments” activity of the viral protein that is expected to hamper the tumor parenchymal/stromal crosstalk. The complex antitumor activities of ARV p17 open the way to a new promising field of research aimed to develop new therapeutic approaches for treating tumor and cancer metastasis.

Novel insights into plasma biomarker candidates in patients with chronic mountain sickness based on proteomics

Chronic mountain sickness (CMS) is a progressive incapacitating syndrome induced by lifelong exposure to hypoxia. In the present study, proteomic analysis was used to identify the differentially expressed proteins (DEPs) and then evaluate the potential plasma biomarkers between CMS and non-CMS groups. A total of 145 DEPs were detected in CMS Han Chinese people who live in the plateau (CMS-HPu), among which 89 were significantly up-regulated and 56 were significantly down-regulated. GO enrichment analysis showed that various biological processes were enriched, including the hydrogen peroxide metabolic/catabolic process, reactive oxygen species (ROS) metabolic, and acute inflammatory response. Protein–protein interaction analysis showed that antioxidant activity, the hydrogen peroxide catabolic process and peroxidase activity were primarily mapped in interaction proteins. Nine modules showed significantly clustering based on WGCNA analysis, with two being the most significant, and GO analysis showed that proteins of both modules were primarily enriched in oxidative stress-related biological processes. Four DEPs increased in CMS patients were evaluated as the candidate biomarkers, and three showed significant AUC: hemoglobin β chain (HB-β), thioredoxin-1 (TRX1), and phosphoglycerate kinase 1 (PGK1). The present study provides insights into the pathogenesis of CMS and further evaluates the potentially biomarkers for its prevention and treatment of it.

Downregulation of long non-protein coding RNA MVIH impairs glioblastoma cell proliferation and invasion through an miR-302a-dependent mechanism

Glioblastoma (GB) is the most frequent and malignant type of brain tumor, for which no effective therapy exists. The high proliferative and invasive nature of GB, as well as its acquired resistance to chemotherapy, makes this type of cancer extremely lethal shortly after diagnosis. Long non-protein coding RNAs (lncRNA) are a class of regulatory RNAs whose levels can be dysregulated in the context of diseases, unbalancing several physiological processes. The lncRNA associated with microvascular invasion in hepatocellular carcinoma (lncRNA-MVIH), overexpressed in several cancers, was described to co-precipitate with phosphoglycerate kinase 1 (PGK1), preventing secretion of this enzyme to the extracellular environment and promoting cell migration and invasion. We hypothesized that, by silencing the expression of lncRNA-MVIH, the secretion of PGK1 would increase, reducing GB cell migration and invasion capabilities. We observed that lncRNA-MVIH silencing in human GB cells significantly decreased glycolysis, cell growth, migration, and invasion and sensitized GB cells to cediranib. However, no increase in extracellular PGK1 was observed as a consequence of lncRNA-MVIH silencing, and therefore, we investigated the possibility of a mechanism of miRNA sponge of lncRNA-MVIH being in place. We found that the levels of miR-302a loaded onto RISC increased in GB cells after lncRNA-MVIH silencing, with the consequent downregulation of several miR-302a molecular targets. Our findings suggest a new mechanism of action of lncRNA-MVIH as a sponge of miR-302a. We suggest that lncRNA-MVIH knockdown may be a promising strategy to address GB invasiveness and chemoresistance, holding potential towards its future application in a clinical context.

The Role of the CXCL12/CXCR4/CXCR7 Chemokine Axis in Cancer

Chemokines are a family of small, secreted cytokines which regulate a variety of cell functions. The C-X-C motif chemokine ligand 12 (CXCL12) binds to C-X-C chemokine receptor type 4 (CXCR4) and C-X-C chemokine receptor type 7 (CXCR7). The interaction of CXCL12 and its receptors subsequently induces downstream signaling pathways with broad effects on chemotaxis, cell proliferation, migration, and gene expression. Accumulating evidence suggests that the CXCL12/CXCR4/CXCR7 axis plays a pivotal role in tumor development, survival, angiogenesis, metastasis, and tumor microenvironment. In addition, this chemokine axis promotes chemoresistance in cancer therapy via complex crosstalk with other pathways. Multiple small molecules targeting CXCR4/CXCR7 have been developed and used for preclinical and clinical cancer treatment. In this review, we describe the roles of the CXCL12/CXCR4/CXCR7 axis in cancer progression and summarize strategies to develop novel targeted cancer therapies.

Identification of a novel non-ATP-competitive protein kinase inhibitor of PGK1 from marine nature products

Phosphoglycerate kinase 1 (PGK1) acts as both a glycolytic enzyme and a protein kinase playing critical roles in cancer progression, thereby being regarded as an attractive therapeutic target for cancer treatment. However, no effective inhibitor of PGK1 has been reported. Here, we demonstrate that GQQ-792, a thiodiketopiperazine derivative from marine nature products, is a non-ATP-competitive inhibitor of PGK1 with the disulfide group within the structure of GQQ-792 as a key pharmacophore. The disulfide group of GQQ-792 binds to Cys379 and Cys380 of PGK1, resulting in occlusion of ATP from binding to PGK1. GQQ-792 treatment blocks hypoxic condition- and EGF stimulation-enhanced protein kinase activity of PGK1 that phosphorylates PDHK1 at T338 in glioblastoma cells; this treatment leads to decreased lactate production and glucose uptake, and subsequent apoptosis of glioblastoma cells. Animal studies reveal that GQQ-792 significantly inhibits the growth of tumor derived from glioblastoma cells. These findings underscore the potential of GQQ-792 as a promising anticancer agent and pave an avenue to further optimize the structure of GQQ-792 basing on its target molecule and pharmacophore in future.

Cytokines and Chemokines as Mediators of Prostate Cancer Metastasis

The consequences of prostate cancer metastasis remain severe, with huge impact on the mortality and overall quality of life of affected patients. Despite the convoluted interplay and cross talk between various cell types and secreted factors in the metastatic process, cytokine and chemokines, along with their receptors and signaling axis, constitute important factors that help drive the sequence of events that lead to metastasis of prostate cancer. These proteins are involved in extracellular matrix remodeling, epithelial-mesenchymal-transition, angiogenesis, tumor invasion, premetastatic niche creation, extravasation, re-establishment of tumor cells in secondary organs as well as the remodeling of the metastatic tumor microenvironment. This review presents an overview of the main cytokines/chemokines, including IL-6, CXCL12, TGFβ, CXCL8, VEGF, RANKL, CCL2, CX3CL1, IL-1, IL-7, CXCL1, and CXCL16, that exert modulatory roles in prostate cancer metastasis. We also provide extensive description of their aberrant expression patterns in both advanced disease states and metastatic sites, as well as their functional involvement in the various stages of the prostate cancer metastatic process.

Extracellular vesicles released by adipose tissue-derived mesenchymal stromal/stem cells from obese pigs fail to repair the injured kidney

AIMS

Mesenchymal stromal/stem cell (MSC)-derived extracellular vesicles (EVs) shuttle select MSC contents and are endowed with an ability to repair ischemic tissues. We hypothesized that exposure to cardiovascular risk factors may alter the microRNA cargo of MSC-derived EVs, blunting their capacity to repair the post-stenotic kidney in pigs with metabolic syndrome (MetS) and renal artery stenosis (RAS).

METHODS

Porcine MSCs were harvested from abdominal fat after 16wks of Lean- or MetS-diet, and their EVs isolated and characterized using microRNA-sequencing. Lean- and MetS-EV protective effects were assessed in-vitro in human umbilical endothelial cells (HUVECs). To compare their in-vivo efficacy to repair ischemic tissues, allogeneic-EVs were intrarenally delivered in pigs after 6wks of MetS + RAS, and 4wks later, single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were studied in-vivo, and microvascular architecture and injury ex-vivo. Lean-, MetS-, and MetS + RAS-sham served as controls (n = 6 each).

RESULTS

Ten microRNAs, capable of targeting several pro-angiogenic genes, were upregulated in MetS-EVs versus Lean-EVs. In vitro, MetS-EVs failed to increase tube number and length, and to boost HUVEC migration compared to Lean-EVs. Lean- and MetS-EVs were detected in the stenotic-kidney 4wks after injection in the vicinity of small vessels. RBF and GFR were lower in MetS + RAS versus MetS, and restored in MetS + RAS + Lean-EVs, but not in MetS + RAS + MetS-EVs. Furthermore, MetS-EVs failed to restore renal expression of angiogenic factors, improve microvascular density, or attenuate fibrosis.

CONCLUSIONS

MetS alters the microRNA cargo of MSC-derived EVs and impairs their functional potency, limiting the therapeutic efficacy of this endogenous cellular repair system.

Phosphoglycerate kinase 1 (PGK1) in cancer: A promising target for diagnosis and therapy

Phosphoglycerate kinase 1 (PGK1) is the first critical enzyme to produce ATP in the glycolytic pathway. PGK1 is not only a metabolic enzyme but also a protein kinase, which mediates the tumor growth, migration and invasion through phosphorylation some important substrates. Moreover, PGK1 is associated with poor treatment and prognosis of cancers. This manuscript reviews the structure, functions, post-translational modifications (PTMs) of PGK1 and its relationship with tumors, which demonstrates that PGK1 has indispensable value in the tumor progression. The current review highlights the important role of PGK1 in anticancer treatments.

Localisation of PGK1 determines metabolic phenotype to balance metastasis and proliferation in patients with SMAD4-negative pancreatic cancer

OBJECTIVE

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive type of GI tumour, and it possesses deregulated cellular energetics. Although recent advances in PDAC biology have led to the discovery of recurrent genetic mutations in Kras, TP53 and SMAD4, which are related to this disease, clinical application of the molecular phenotype of PDAC remains challenging.

DESIGN

We combined molecular imaging technology (positron emission tomography/CT) and immunohistochemistry to evaluate the correlation between the maximum standardised uptake value and SMAD4 expression and examined the effect of SMAD4 on glycolysis through in vitro and in vivo experiments. Furthermore, we identified the effect of SMAD4 on metabolic reprogramming by metabolomics and glucose metabolism gene expression analyses. Dual luciferase reporter assays and chromatin immunoprecipitation were performed to identify whether SMAD4 functioned as a transcription factor for phosphoglycerate kinase 1 (PGK1) in PDAC cells. Proliferative and metastatic assays were performed to examine the effect of PGK1 on the malignant behaviour of PDAC.

RESULTS

We provide compelling evidence that the glycolytic enzyme PGK1 is repressed by transforming growth factor-β/SMAD4. Loss of SMAD4 induces PGK1 upregulation in PDAC, which enhances glycolysis and aggressive tumour behaviour. Notably, in SMAD4-negative PDAC, nuclear PGK1 preferentially drives cell metastasis via mitochondrial oxidative phosphorylation induction, whereas cytoplasmic PGK1 preferentially supports proliferation by functioning as a glycolytic enzyme. The PDAC progression pattern and distinct PGK1 localisation combine to predict overall survival and disease-free survival.

CONCLUSION

PGK1 is a decisive oncogene in patients with SMAD4-negative PDAC and can be a target for the development of a therapeutic strategy for SMAD4-negative PDAC.

The Warburg Effect and lactate signaling augment Fgf-MAPK to promote sensory-neural development in the otic vesicle

Recent studies indicate that many developing tissues modify glycolysis to favor lactate synthesis (Agathocleous et al., 2012; Bulusu et al., 2017; Gu et al., 2016; Oginuma et al., 2017; Sá et al., 2017; Wang et al., 2014; Zheng et al., 2016), but how this promotes development is unclear. Using forward and reverse genetics in zebrafish, we show that disrupting the glycolytic gene phosphoglycerate kinase-1 (pgk1) impairs Fgf-dependent development of hair cells and neurons in the otic vesicle and other neurons in the CNS/PNS. Fgf-MAPK signaling underperforms in pgk1- / - mutants even when Fgf is transiently overexpressed. Wild-type embryos treated with drugs that block synthesis or secretion of lactate mimic the pgk1- / - phenotype, whereas pgk1- / - mutants are rescued by treatment with exogenous lactate. Lactate treatment of wild-type embryos elevates expression of Etv5b/Erm even when Fgf signaling is blocked. However, lactate’s ability to stimulate neurogenesis is reversed by blocking MAPK. Thus, lactate raises basal levels of MAPK and Etv5b (a critical effector of the Fgf pathway), rendering cells more responsive to dynamic changes in Fgf signaling required by many developing tissues.

SCNrank: spectral clustering for network-based ranking to reveal potential drug targets and its application in pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic malignancy. Due to its wide heterogeneity, PDAC acts aggressively and responds poorly to most chemotherapies, causing an urgent need for the development of new therapeutic strategies. Cell lines have been used as the foundation for drug development and disease modeling. CRISPR-Cas9 plays a key role in every step-in drug discovery: from target identification and validation to preclinical cancer cell testing. Using cell-line models and CRISPR-Cas9 technology together make drug target prediction feasible. However, there is still a large gap between predicted results and actionable targets in real tumors. Biological network models provide great modus to mimic genetic interactions in real biological systems, which can benefit gene perturbation studies and potential target identification for treating PDAC. Nevertheless, building a network model that takes cell-line data and CRISPR-Cas9 data as input to accurately predict potential targets that will respond well on real tissue remains unsolved.

Methods

We developed a novel algorithm ‘Spectral Clustering for Network-based target Ranking’ (SCNrank) that systematically integrates three types of data: expression profiles from tumor tissue, normal tissue and cell-line PDAC; protein-protein interaction network (PPI); and CRISPR-Cas9 data to prioritize potential drug targets for PDAC. The whole algorithm can be classified into three steps: 1. using STRING PPI network skeleton, SCNrank constructs tissue-specific networks with PDAC tumor and normal pancreas tissues from expression profiles; 2. With the same network skeleton, SCNrank constructs cell-line-specific networks using the cell-line PDAC expression profiles and CRISPR-Cas 9 data from pancreatic cancer cell-lines; 3. SCNrank applies a novel spectral clustering approach to reduce data dimension and generate gene clusters that carry common features from both networks. Finally, SCNrank applies a scoring scheme called ‘Target Influence score’ (TI), which estimates a given target’s influence towards the cluster it belongs to, for scoring and ranking each drug target.

Results

We applied SCNrank to analyze 263 expression profiles, CRPSPR-Cas9 data from 22 different pancreatic cancer cell-lines and the STRING protein-protein interaction (PPI) network. With SCNrank, we successfully constructed an integrated tissue PDAC network and an integrated cell-line PDAC network, both of which contain 4414 selected genes that are overexpressed in tumor tissue samples. After clustering, 4414 genes are distributed into 198 clusters, which include 367 targets of FDA approved drugs. These drug targets are all scored and ranked by their TI scores, which we defined to measure their influence towards the network. We validated top-ranked targets in three aspects: Firstly, mapping them onto the existing clinical drug targets of PDAC to measure the concordance. Secondly, we performed enrichment analysis to these drug targets and the clusters there are within, to reveal functional associations between clusters and PDAC; Thirdly, we performed survival analysis for the top-ranked targets to connect targets with clinical outcomes. Survival analysis reveals that overexpression of three top-ranked genes, PGK1, HMMR and POLE2, significantly increases the risk of death in PDAC patients.

Conclusion

SCNrank is an unbiased algorithm that systematically integrates multiple types of omics data to do potential drug target selection and ranking. SCNrank shows great capability in predicting drug targets for PDAC. Pancreatic cancer-associated gene candidates predicted by our SCNrank approach have the potential to guide genetics-based anti-pancreatic drug discovery.

Characterization and role of PGK from Litopenaeus vannamei in WSSV infection

Phosphoglycerate kinase (EC 2.7.2.3, PGK) catalyses the reversible transfer of a phosphate group from 1,3-diphosphoglyceric acid and ADP to produce 3-phosphoglyceric acid and ATP, which represents the initial production of ATP during glycolysis; therefore, PGK is a key enzyme in the energy metabolism. To study the role of PGK in the resistance to WSSV infection in shrimp, the full-length cDNA of the PGK gene (LvPGK) from Litopenaeus vannamei was obtained by using homology cloning and RACE amplification. The tissue distribution of LvPGK and its expression changes in the main immune tissues after WSSV stimulation were obtained by quantitative real-time PCR. Furthermore, RNA interference (RNAi) was used to study the role of LvPGK in shrimp defending against WSSV infection. The results showed that the full-length cDNA sequence of LvPGK was 1855 bp, contained a 1248 bp open reading frame (ORF) encoding 415 amino acids, and included a conserved PGK domain. LvPGK presented ubiquitous expression in most examined tissues, with the most predominant expression in the muscle and the weakest expression in the intestine. LvPGK transcripts could be induced in the hemocytes and hepatopancreas by injection with WSSV. Both the replication of WSSV and the shrimp cumulative mortality decreased significantly after LvPGK knockdown (P < 0.01). After challenging LvPGK RNAi shrimp with WSSV, the concentration of glucose in the hepatopancreas and muscle tissue did not show significant change; however, the content of pyruvate and lactate decreased significantly (P < 0.05). Moreover, significant decreases in the expression levels of crustin, ALF1, ALF2 and ALF3 were also detected. The results suggested that LvPGK might be involved in WSSV replication by increasing host aerobic and anaerobic metabolism.

Extracellular Pgk1 enhances neurite outgrowth of motoneurons through Nogo66/NgR-independent targeting of NogoA

NogoA inhibits neurite outgrowth of motoneurons (NOM) through interaction with its receptors, Nogo66/NgR. Inhibition of Nogo receptors rescues NOM, but not to the extent exhibited by NogoA-knockout mice, suggesting the presence of other pathways. We found that NogoA-overexpressing muscle cells reduced phosphoglycerate kinase 1 (Pgk1) secretion, resulting in inhibiting NOM. Apart from its glycolytic role and independent of the Nogo66 pathway, extracellular Pgk1 stimulated NOM by triggering a reduction of p-Cofilin-S3, a growth cone collapse marker, through decreasing a novel Rac1-GTP/p-Pak1-T423/p-P38-T180/p-MK2-T334/p-Limk1-S323/p-Cofilin-S3 molecular pathway. Not only did supplementary Pgk1 enhance NOM in defective cells, but injection of Pgk1 rescued denervation in muscle-specific NogoA-overexpression of zebrafish and an Amyotrophic Lateral Sclerosis mouse model, SOD1 G93A. Thus, Pgk1 secreted from muscle is detrimental to motoneuron neurite outgrowth and maintenance.

Multi-dimensional immunoproteomics coupled with in vitro recapitulation of oncogenic NRASQ61R identifies diagnostically relevant autoantibody biomarkers in thyroid neoplasia

Tumor-associated antigen (TAA)-specific autoantibodies have been widely implicated in cancer diagnosis. However, cancer cell lines that are typically exploited as candidate TAA sources in immunoproteomic studies may fail to accurately represent the autoantigen-ome of lower-grade neoplasms. Here, we established an integrated strategy for the identification of disease-relevant TAAs in thyroid neoplasia, which combined NRAS^Q61R oncogene expression in non-tumorous thyroid Nthy-ori 3-1 cells with a multi-dimensional proteomic technique DISER that consisted of profiling NRAS^Q61R-induced proteins using 2-dimensional difference gel electrophoresis (2D-DIGE) coupled with serological proteome analysis (SERPA) of the TAA repertoire of patients with thyroid encapsulated follicular-patterned/RAS-like phenotype (EFP/RLP) tumors. We identified several candidate cell-based (nicotinamide phosphoribosyltransferase NAMPT, glutamate dehydrogenase GLUD1, and glutathione S-transferase omega-1 GSTO1) and autoantibody (fumarate hydratase FH, calponin-3 CNN3, and pyruvate kinase PKM autoantibodies) biomarkers, including NRAS^Q61R-induced TAA phosphoglycerate kinase 1 PGK1. Meta-profiling of the reactivity of the identified autoantibodies across an independent SERPA series implicated the PKM autoantibody as a histological phenotype-independent biomarker of thyroid malignancy (11/38 (29%) patients with overtly malignant and uncertain malignant potential (UMP) tumors vs 0/22 (p = 0.0046) and 0/20 (p = 0.011) patients with non-invasive EFP/RLP tumors and healthy controls, respectively). PGK1 and CNN3 autoantibodies were identified as EFP/RLP-specific biomarkers, potentially suitable for further discriminating tumors with different malignant potential (PGK1: 7/22 (32%) patients with non-invasive EFP/RLP tumors vs 0/38 (p = 0.00044) and 0/20 (p = 0.0092) patients with other tumors and healthy controls, respectively; СNN3: 9/29 (31%) patients with malignant and borderline EFP/RLP tumors vs 0/31 (p = 0.00068) and 0/20 (p = 0.0067) patients with other tumors and healthy controls, respectively). The combined use of PKM, CNN3, and PGK1 autoantibodies allowed the reclassification of malignant/UMP tumor risk in 19/41 (46%) of EFP/RLP tumor patients. Taken together, we established an experimental pipeline DISER for the concurrent identification of cell-based and TAA biomarkers. The combination of DISER with in vitro oncogene expression allows further targeted identification of oncogene-induced TAAs. Using this integrated approach, we identified candidate autoantibody biomarkers that might be of value for differential diagnostic purposes in thyroid neoplasia.

The CIMP-high phenotype is associated with energy metabolism alterations in colon adenocarcinoma

BACKGROUND

CpG island methylator phenotype (CIMP) is found in 15-20% of malignant colorectal tumors and is characterized by strong CpG hypermethylation over the genome. The molecular mechanisms of this phenomenon are not still fully understood. The development of CIMP is followed by global gene expression alterations and metabolic changes. In particular, CIMP-low colon adenocarcinoma (COAD), predominantly corresponded to consensus molecular subtype 3 (CMS3, "Metabolic") subgroup according to COAD molecular classification, is associated with elevated expression of genes participating in metabolic pathways.

METHODS

We performed bioinformatics analysis of RNA-Seq data from The Cancer Genome Atlas (TCGA) project for CIMP-high and non-CIMP COAD samples with DESeq2, clusterProfiler, and topGO R packages. Obtained results were validated on a set of fourteen COAD samples with matched morphologically normal tissues using quantitative PCR (qPCR).

RESULTS

Upregulation of multiple genes involved in glycolysis and related processes (ENO2, PFKP, HK3, PKM, ENO1, HK2, PGAM1, GAPDH, ALDOA, GPI, TPI1, and HK1) was revealed in CIMP-high tumors compared to non-CIMP ones. Most remarkably, the expression of the PKLR gene, encoding for pyruvate kinase participating in gluconeogenesis, was decreased approximately 20-fold. Up to 8-fold decrease in the expression of OGDHL gene involved in tricarboxylic acid (TCA) cycle was observed in CIMP-high tumors. Using qPCR, we confirmed the increase (4-fold) in the ENO2 expression and decrease (2-fold) in the OGDHL mRNA level on a set of COAD samples.

CONCLUSIONS

We demonstrated the association between CIMP-high status and the energy metabolism changes at the transcriptomic level in colorectal adenocarcinoma against the background of immune pathway activation. Differential methylation of at least nine CpG sites in OGDHL promoter region as well as decreased OGDHL mRNA level can potentially serve as an additional biomarker of the CIMP-high status in COAD.

Potential new biomarkers for endometrial cancer

BACKGROUND

Incidence of endometrial cancer are rising both in the United States and worldwide. As endometrial cancer becomes more prominent, the need to develop and characterize biomarkers for early stage diagnosis and the treatment of endometrial cancer has become an important priority. Several biomarkers currently used to diagnose endometrial cancer are directly related to obesity. Although epigenetic and mutational biomarkers have been identified and have resulted in treatment options for patients with specific aberrations, many tumors do not harbor those specific aberrations. A promising alternative is to determine biomarkers based on differential gene expression, which can be used to estimate prognosis.

METHODS

We evaluated 589 patients to determine differential expression between normal and malignant patient samples. We then supplemented these evaluations with immunohistochemistry staining of endometrial tumors and normal tissues. Additionally, we used the Library of Integrated Network-based Cellular Signatures to evaluate the effects of 1826 chemotherapy drugs on 26 cell lines to determine the effects of each drug on HPRT1 and AURKA expression.

RESULTS

Expression of HPRT1, Jag2, AURKA, and PGK1 were elevated when compared to normal samples, and HPRT1 and PGK1 showed a stepwise elevation in expression that was significantly related to cancer grade. To determine the prognostic potential of these genes, we evaluated patient outcome and found that levels of both HPRT1 and AURKA were significantly correlated with overall patient survival. When evaluating drugs that had the most significant effect on lowering the expression of HPRT1 and AURKA, we found that Topo I and MEK inhibitors were most effective at reducing HPRT1 expression. Meanwhile, drugs that were effective at reducing AURKA expression were more diverse (MEK, Topo I, MELK, HDAC, etc.). The effects of these drugs on the expression of HPRT1 and AURKA provides insight into their role within cellular maintenance.

CONCLUSIONS

Collectively, these data show that JAG2, AURKA, PGK1, and HRPT1 have the potential to be used independently as diagnostic, prognostic, or treatment biomarkers in endometrial cancer. Expression levels of these genes may provide physicians with insight into tumor aggressiveness and chemotherapy drugs that are well suited to individual patients.

Oncogenic Metabolism Acts as a Prerequisite Step for Induction of Cancer Metastasis and Cancer Stem Cell Phenotype

Metastasis is a major obstacle to the efficient and successful treatment of cancer. Initiation of metastasis requires epithelial-mesenchymal transition (EMT) that is regulated by several transcription factors, including Snail and ZEB1/2. EMT is closely linked to the acquisition of cancer stem cell (CSC) properties and chemoresistance, which contribute to tumor malignancy. Tumor suppressor p53 inhibits EMT and metastasis by negatively regulating several EMT-inducing transcription factors and regulatory molecules; thus, its inhibition is crucial in EMT, invasion, metastasis, and stemness. Metabolic alterations are another hallmark of cancer. Most cancer cells are more dependent on glycolysis than on mitochondrial oxidative phosphorylation for their energy production, even in the presence of oxygen. Cancer cells enhance other oncogenic metabolic pathways, such as glutamine metabolism, pentose phosphate pathway, and the synthesis of fatty acids and cholesterol. Metabolic reprogramming in cancer is regulated by the activation of oncogenes or loss of tumor suppressors that contribute to tumor progression. Oncogenic metabolism has been recently linked closely with the induction of EMT or CSC phenotypes by the induction of several metabolic enzyme genes. In addition, several transcription factors and molecules involved in EMT or CSCs, including Snail, Dlx-2, HIF-1α, STAT3, TGF-β, Wnt, and Akt, regulate oncogenic metabolism. Moreover, p53 induces metabolic change by directly regulating several metabolic enzymes. The collective data indicate the importance of oncogenic metabolism in the regulation of EMT, cell invasion and metastasis, and adoption of the CSC phenotype, which all contribute to malignant transformation and tumor development. In this review, we highlight the oncogenic metabolism as a key regulator of EMT and CSC, which is related with tumor progression involving metastasis and chemoresistance. Targeting oncometabolism might be a promising strategy for the development of effective anticancer therapy.

Quantitative Global Proteome and Lysine Succinylome Analyses Reveal the Effects of Energy Metabolism in Renal Cell Carcinoma

In light of the increasing incidence of renal cell carcinoma (RCC), its molecular mechanisms have been comprehensively explored in numerous recent studies. However, few studies focus on the influence of multi-factor interactions during the occurrence and development of RCC. This study aims to investigate the quantitative global proteome and the changes in lysine succinylation in related proteins, seeking to facilitate a better understanding of the molecular mechanisms underlying RCC. LC-MS/MS combined with bioinformatics analysis are used to quantitatively detect the perspectives at the global protein level. IP and WB analysis were conducted to further verify the alternations of related proteins and lysine succinylation. A total of 3,217 proteins and 1,238 lysine succinylation sites are quantified in RCC tissues, and 668 differentially expressed proteins and 161 differentially expressed lysine succinylation sites are identified. Besides, expressions of PGK1 and PKM2 at protein and lysine, succinylation levels are significantly altered in RCC tissues. Bioinformatics analysis indicates that the glycolysis pathway is a potential mechanism of RCC progression and lysine succinylation may plays a potential role in energy metabolism. These results can provide a new direction for exploring the molecular mechanism of RCC tumorigenesis.

The phosphoglycerate kinase 1 variants found in carcinoma cells display different catalytic activity and conformational stability compared to the native enzyme

Cancer cells are able to survive in difficult conditions, reprogramming their metabolism according to their requirements. Under hypoxic conditions they shift from oxidative phosphorylation to aerobic glycolysis, a behavior known as Warburg effect. In the last years, glycolytic enzymes have been identified as potential targets for alternative anticancer therapies. Recently, phosphoglycerate kinase 1 (PGK1), an ubiquitous enzyme expressed in all somatic cells that catalyzes the seventh step of glycolysis which consists of the reversible phosphotransfer reaction from 1,3-bisphosphoglycerate to ADP, has been discovered to be overexpressed in many cancer types. Moreover, several somatic variants of PGK1 have been identified in tumors. In this study we analyzed the effect of the single nucleotide variants found in cancer tissues on the PGK1 structure and function. Our results clearly show that the variants display a decreased catalytic efficiency and/or thermodynamic stability and an altered local tertiary structure, as shown by the solved X-ray structures. The changes in the catalytic properties and in the stability of the PGK1 variants, mainly due to the local changes evidenced by the X-ray structures, suggest also changes in the functional role of PGK to support the biosynthetic need of the growing and proliferating tumour cells.

Chemokines in homeostasis and diseases

For the past twenty years, chemokines have emerged as a family of critical mediators of cell migration during immune surveillance, development, inflammation and cancer progression. Chemokines bind to seven transmembrane G protein-coupled receptors (GPCRs) that are expressed by a wide variety of cell types and cause conformational changes in trimeric G proteins that trigger the intracellular signaling pathways necessary for cell movement and activation. Although chemokines have evolved to benefit the host, inappropriate regulation or utilization of these small proteins may contribute to or even cause diseases. Therefore, understanding the role of chemokines and their GPCRs in the complex physiological and diseased microenvironment is important for the identification of novel therapeutic targets. This review introduces the functional array and signals of multiple chemokine GPCRs in guiding leukocyte trafficking as well as their roles in homeostasis, inflammation, immune responses and cancer.

Regulation of Tumor Progression by Programmed Necrosis

Rapidly growing malignant tumors frequently encounter hypoxia and nutrient (e.g., glucose) deprivation, which occurs because of insufficient blood supply. This results in necrotic cell death in the core region of solid tumors. Necrotic cells release their cellular cytoplasmic contents into the extracellular space, such as high mobility group box 1 (HMGB1), which is a nonhistone nuclear protein, but acts as a proinflammatory and tumor-promoting cytokine when released by necrotic cells. These released molecules recruit immune and inflammatory cells, which exert tumor-promoting activity by inducing angiogenesis, proliferation, and invasion. Development of a necrotic core in cancer patients is also associated with poor prognosis. Conventionally, necrosis has been thought of as an unregulated process, unlike programmed cell death processes like apoptosis and autophagy. Recently, necrosis has been recognized as a programmed cell death, encompassing processes such as oncosis, necroptosis, and others. Metabolic stress-induced necrosis and its regulatory mechanisms have been poorly investigated until recently. Snail and Dlx-2, EMT-inducing transcription factors, are responsible for metabolic stress-induced necrosis in tumors. Snail and Dlx-2 contribute to tumor progression by promoting necrosis and inducing EMT and oncogenic metabolism. Oncogenic metabolism has been shown to play a role(s) in initiating necrosis. Here, we discuss the molecular mechanisms underlying metabolic stress-induced programmed necrosis that promote tumor progression and aggressiveness.

PGK1 and GRP78 overexpression correlates with clinical significance and poor prognosis in Chinese endometrial cancer patients

The aim of this study was to measure the expression patterns of PGK1 and GRP78 in normal endometrial tissues and endometrial carcinoma, and associations between their combined effects and the pathological features of endometrial carcinoma. We used 30 normal endometrial tissue samples and 130 endometrial carcinoma samples, and separately evaluated PGK1 and GRP78 protein expression by immunohistochemistry. Scores ranging from 0 to 9 were obtained by multiplying the percentage of positive cells by the staining intensity (0–3). Immunohistochemical analysis revealed increased PGK1 and GRP78 expression in the cytoplasm of endometrial carcinoma cells compared with that in normal endometrial tissues. High PGK1 expression positively correlated with the FIGO stage (P < 0.001), histological grade (P = 0.002), and lymph node status (P < 0.001). High GRP78 expression positively correlated with the pathological type (P = 0.0125), FIGO stage (P < 0.001), and lymph node status (P < 0.001). In addition, PGK1 overexpression was positively correlated with GRP78 overexpression in endometrial carcinoma patients (P < 0.001), and the concurrent expression of both oncogenes in endometrial carcinoma patients correlated significantly with the lymph node status (P < 0.001) and FIGO stage (P < 0.001). Patients with high PGK1 and GRP78 expression levels had poorer overall survival rates than those with low expression levels of both proteins (P < 0.001). Our results suggested that the co-occurrence of PGK1 and GRP78 expression is potentially an unfavorable factor for endometrial carcinoma progression.

Endogenous GAS6 and Mer receptor signaling regulate prostate cancer stem cells in bone marrow

GAS6 and its receptors (Tryo 3, Axl, Mer or “TAM”) are known to play a role in regulating tumor progression in a number of settings. Previously we have demonstrated that GAS6 signaling regulates invasion, proliferation, chemotherapy-induced apoptosis of prostate cancer (PCa) cells. We have also demonstrated that GAS6 secreted from osteoblasts in the bone marrow environment plays a critical role in establishing prostate tumor cell dormancy. Here we investigated the role that endogenous GAS6 and Mer receptor signaling plays in establishing prostate cancer stem cells in the bone marrow microenvironment.

We first observed that high levels of endogenous GAS6 are expressed by disseminated tumor cells (DTCs) in the bone marrow, whereas relatively low levels of endogenous GAS6 are expressed in PCa tumors grown in a s.c. setting. Interestingly, elevated levels of endogenous GAS6 were identified in putative cancer stem cells (CSCs, CD133+/CD44+) compared to non-CSCs (CD133–/CD44–) isolated from PCa/osteoblast cocultures in vitro and in DTCs isolated from the bone marrow 24 hours after intracardiac injection. Moreover, we found that endogenous GAS6 expression is associated with Mer receptor expression in growth arrested (G₁) PCa cells, which correlates with the increase of the CSC populations. Importantly, we found that overexpression of GAS6 activates phosphorylation of Mer receptor signaling and subsequent induction of the CSC phenotype in vitro and in vivo.

Together these data suggest that endogenous GAS6 and Mer receptor signaling contribute to the establishment of PCa CSCs in the bone marrow microenvironment, which may have important implications for targeting metastatic disease.

Interactive phenotyping of large-scale histology imaging data with HistomicsML

Whole-slide imaging of histologic sections captures tissue microenvironments and cytologic details in expansive high-resolution images. These images can be mined to extract quantitative features that describe tissues, yielding measurements for hundreds of millions of histologic objects. A central challenge in utilizing this data is enabling investigators to train and evaluate classification rules for identifying objects related to processes like angiogenesis or immune response. In this paper we describe HistomicsML, an interactive machine-learning system for digital pathology imaging datasets. This framework uses active learning to direct user feedback, making classifier training efficient and scalable in datasets containing 10⁸+ histologic objects. We demonstrate how this system can be used to phenotype microvascular structures in gliomas to predict survival, and to explore the molecular pathways associated with these phenotypes. Our approach enables researchers to unlock phenotypic information from digital pathology datasets to investigate prognostic image biomarkers and genotype-phenotype associations.

Role of SDF-1α/CXCR4 signaling pathway in clinicopathological features and prognosis of patients with nasopharyngeal carcinoma

The present study aims to explore the role of stromal cell-derived factor-1α (SDF-1α)/stromal cell-derived factor receptor-4 (CXCR4) signaling pathway to the clinicopathological features and prognosis of patients with nasopharyngeal carcinoma (NPC). From January 2009 to December 2010, 102 patients with NPC and 80 patients with chronic nasopharyngitis were enrolled for the study. Immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting were employed to determine the expressions of SDF-1α and CXCR4 proteins in NPC tissues and chronic nasopharyngitis tissues. Chi-square test was conducted to analyze the associations of the expressions of SDF-1α and CXCR4 proteins with the clinicopathological features of NPC patients. Spearman rank correlation analysis was used to analyze the correlation between the SDF-1α protein expression and CXCR4 protein expression. The mRNA and protein expressions of SDF-1α and CXCR4 in NPC tissues were significantly higher than those in chronic nasopharyngitis tissues. The expressions of SDF-1α and CXCR4 proteins showed associations with T staging, N staging, tumor node metastasis (TNM) staging, skull base invasion, and cervical lymph node metastasis of NPC patients. Compared with NPC patients showing negative expressions of SDF-1α and CXCR4 proteins, those with positive expressions of SDF-1α and CXCR4 proteins had a significantly shorter survival time. SDF-1α protein, CXCR4 protein, EBV-IgG status, T staging, N staging, TNM staging, skull base invasion, and cervical lymph node metastasis were independent risk factors for the prognosis of NPC. The findings indicated that SDF-1α/CXCR4 signaling pathway might be associated with the clinicopathological features and prognosis of patients with NPC.

Retrospective Proteomic Screening of 100 Breast Cancer Tissues

The present investigation has been conducted on one hundred tissue fragments of breast cancer, collected and immediately cryopreserved following the surgical resection. The specimens were selected from patients with invasive ductal carcinoma of the breast, the most frequent and potentially aggressive type of mammary cancer, with the objective to increase the knowledge of breast cancer molecular markers potentially useful for clinical applications. The proteomic screening; by 2D-IPG and mass spectrometry; allowed us to identify two main classes of protein clusters: proteins expressed ubiquitously at high levels in all patients; and proteins expressed sporadically among the same patients. Within the group of ubiquitous proteins, glycolytic enzymes and proteins with anti-apoptotic activity were predominant. Among the sporadic ones, proteins involved in cell motility, molecular chaperones and proteins involved in the detoxification appeared prevalent. The data of the present study indicates that the primary tumor growth is reasonably supported by concurrent events: the inhibition of apoptosis and stimulation of cellular proliferation, and the increased expression of glycolytic enzymes with multiple functions. The second phase of the evolution of the tumor can be prematurely scheduled by the occasional presence of proteins involved in cell motility and in the defenses of the oxidative stress. We suggest that this approach on large-scale 2D-IPG proteomics of breast cancer is currently a valid tool that offers the opportunity to evaluate on the same assay the presence and recurrence of individual proteins, their isoforms and short forms, to be proposed as prognostic indicators and susceptibility to metastasis in patients operated on for invasive ductal carcinoma of the breast.

Cofilin-1 and phosphoglycerate kinase 1 as promising indicators for glioma radiosensibility and prognosis

Glioma is a primary malignancy in central nervous system. Radiotherapy has been used as one of the standard treatments for glioma for decades. Since radioresistance can reduce the curative efficacy of radiotherapy in glioma, investigating the cause of radioresistance and predicting the tumour radiosensibility appeared particularly important. We previously reported that CFL1 and PGK1 are over-expressed in radioresistant U251 glioma cells. In this study, the level of CFL1 and PGK1 of 113 glioma tissues were measured by ELISA method. The relevance of the expression of these two proteins to radiosensibility was analyzed by mean test and multivariate logistic regression. The survival analysis was carried out in 85 irradiated patients and 105 followed-up patients respectively. The relationship between protein expression and clinical parameters was explored in overall 113 patients, and the correlation between CFL1 and PGK1 were determined as well. Our results showed that the expression of CFL1 and PGK1 were significantly higher (P < 0.001) in radioresistant patients than others. The multivariate Logistic regression demonstrated that the expression of CFL1 (p < 0.001) and PGK1 (p < 0.001) were associated with radioresistance in glioma. The multivariate Cox regression in overall survival suggested that CFL1 level or PGK1 level could be the independent prognosis factor for poor prognosis in 113 glioma patients. In addition, CFL1 expression was positively correlated with PGK1 expression in glioma. The results suggested that as promising indicators, CFL1 and PGK1 could be used to evaluate glioma radiosensibility and prognosis. These two proteins could also be the potential therapeutic targets of glioma.

17beta-hydroxysteroid dehydrogenase type 5 is negatively correlated to apoptosis inhibitor GRP78 and tumor-secreted protein PGK1, and modulates breast cancer cell viability and proliferation

17beta-hydroxysteroid dehydrogenase type 5 (17β-HSD5) is an important enzyme associated with sex steroid metabolism in hormone-dependent cancer. However, reports on its expression and its prognostic value in breast cancer are inconsistent. Here, we demonstrate the impact of 17β-HSD5 expression modulation on the proteome of estrogen receptor-positive (ER+) breast cancer cells. RNA interference technique (siRNA) was used to knock down 17β-HSD5 gene expression in the ER+ breast cancer cell line MCF-7 and the proteome of the 17β-HSD5-knockdown cells was compared to that of MCF-7 cells using two-dimensional (2-D) gel electrophoresis followed by mass spectrometry analysis. Ingenuity pathway analysis (IPA) was additionally used to assess functional enrichment analyses of the proteomic dataset, including protein network and canonical pathways. Our proteomic analysis revealed only four differentially expressed protein spots (fold change > 2, p<0.05) between the two cell lines. The four spots were up-regulated in 17β-HSD5-knockdown MCF-7 cells, and comprised 21 proteins involved in two networks and in functions that include apoptosis inhibition, regulation of cell growth and differentiation, signal transduction and tumor metastasis. Among the proteins are nucleoside diphosphate kinase A (NME1), 78kDa glucose-regulated protein (GRP78) and phosphoglycerate kinase 1 (PGK1). We also showed that expression of 17β-HSD5 and that of the apoptosis inhibitor GRP78 are strongly but negatively correlated. Consistent with their opposite regulation, GRP78 knockdown decreased MCF-7 cell viability whereas 17β-HSD5 knockdown or inhibition increased cell viability and proliferation. Besides, IPA analysis revealed that ubiquitination pathway is significantly affected by 17β-HSD5 knockdown. Furthermore, IPA predicted the proto-oncogene c-Myc as an upstream regulator linked to the tumor-secreted protein PGK1. The latter is over-expressed in invasive ductal breast carcinoma as compared with normal breast tissue and its expression increased following 17β-HSD5 knockdown. Our present results indicate a 17β-HSD5 role in down-regulating breast cancer development. We thus propose that 17β-HSD5 may not be a potent target for breast cancer treatment but its low expression could represent a poor prognosis factor.

Haploinsufficiency in tumor predisposition syndromes: altered genomic transcription in morphologically normal cells heterozygous for VHL or TSC mutation

Tumor suppressor genes and their effector pathways have been identified for many dominantly heritable cancers, enabling efforts to intervene early in the course of disease. Our approach on the subject of early intervention was to investigate gene expression patterns of morphologically normal "one-hit" cells before they become hemizygous or homozygous for the inherited mutant gene which is usually required for tumor formation. Here, we studied histologically non-transformed renal epithelial cells from patients with inherited disorders that predispose to renal tumors, including von Hippel-Lindau (VHL) disease and Tuberous Sclerosis (TSC). As controls, we studied histologically normal cells from non-cancerous renal epithelium of patients with sporadic clear cell renal cell carcinoma (ccRCC). Gene expression analyses of VHLmut/wt or TSC1/2mut/wt versus wild-type (WT) cells revealed transcriptomic alterations previously implicated in the transition to precancerous renal lesions. For example, the gene expression changes in VHLmut/wt cells were consistent with activation of the hypoxia response, associated, in part, with the "Warburg effect". Knockdown of any remaining VHL mRNA using shRNA induced secondary expression changes, such as activation of NFκB and interferon pathways, that are fundamentally important in the development of RCC. We posit that this is a general pattern of hereditary cancer predisposition, wherein haploinsufficiency for VHL or TSC1/2, or potentially other tumor susceptibility genes, is sufficient to promote development of early lesions, while cancer results from inactivation of the remaining normal allele. The gene expression changes identified here are related to the metabolic basis of renal cancer and may constitute suitable targets for early intervention.

PML promotes metastasis of triple-negative breast cancer through transcriptional regulation of HIF1A target genes

Elucidating the molecular basis of tumor metastasis is pivotal for eradicating cancer-related mortality. Triple-negative breast cancer (TNBC) encompasses a class of aggressive tumors characterized by high rates of recurrence and metastasis, as well as poor overall survival. Here, we find that the promyelocytic leukemia protein PML exerts a prometastatic function in TNBC that can be targeted by arsenic trioxide. We found that, in TNBC patients, constitutive HIF1A activity induces high expression of PML, along with a number of HIF1A target genes that promote metastasis at multiple levels. Intriguingly, PML controls the expression of these genes by binding to their regulatory regions along with HIF1A. This mechanism is specific to TNBC cells and does not occur in other subtypes of breast cancer where PML and prometastatic HIF1A target genes are underexpressed. As a consequence, PML promotes cell migration, invasion, and metastasis in TNBC cell and mouse models. Notably, pharmacological inhibition of PML with arsenic trioxide, a PML-degrading agent used to treat promyelocytic leukemia patients, delays tumor growth, impairs TNBC metastasis, and cooperates with chemotherapy by preventing metastatic dissemination. In conclusion, we report identification of a prometastatic pathway in TNBC and suggest clinical development toward the use of arsenic trioxide for TNBC patients.

Induction of metastasis, cancer stem cell phenotype, and oncogenic metabolism in cancer cells by ionizing radiation

Radiation therapy is one of the major tools of cancer treatment, and is widely used for a variety of malignant tumours. Radiotherapy causes DNA damage directly by ionization or indirectly via the generation of reactive oxygen species (ROS), thereby destroying cancer cells. However, ionizing radiation (IR) paradoxically promotes metastasis and invasion of cancer cells by inducing the epithelial-mesenchymal transition (EMT). Metastasis is a major obstacle to successful cancer therapy, and is closely linked to the rates of morbidity and mortality of many cancers. ROS have been shown to play important roles in mediating the biological effects of IR. ROS have been implicated in IR-induced EMT, via activation of several EMT transcription factors—including Snail, HIF-1, ZEB1, and STAT3—that are activated by signalling pathways, including those of TGF-β, Wnt, Hedgehog, Notch, G-CSF, EGFR/PI3K/Akt, and MAPK. Cancer cells that undergo EMT have been shown to acquire stemness and undergo metabolic changes, although these points are debated. IR is known to induce cancer stem cell (CSC) properties, including dedifferentiation and self-renewal, and to promote oncogenic metabolism by activating these EMT-inducing pathways. Much accumulated evidence has shown that metabolic alterations in cancer cells are closely associated with the EMT and CSC phenotypes; specifically, the IR-induced oncogenic metabolism seems to be required for acquisition of the EMT and CSC phenotypes. IR can also elicit various changes in the tumour microenvironment (TME) that may affect invasion and metastasis. EMT, CSC, and oncogenic metabolism are involved in radioresistance; targeting them may improve the efficacy of radiotherapy, preventing tumour recurrence and metastasis. This study focuses on the molecular mechanisms of IR-induced EMT, CSCs, oncogenic metabolism, and alterations in the TME. We discuss how IR-induced EMT/CSC/oncogenic metabolism may promote resistance to radiotherapy; we also review efforts to develop therapeutic approaches to eliminate these IR-induced adverse effects.

Chemokine Receptor Signaling and the Hallmarks of Cancer

The chemokines are a family of chemotactic cytokines that mediate their activity by acting on seven-transmembrane-spanning G protein-coupled receptors. Both the ability of the chemokines and their receptors to form homo- and heterodimers and the promiscuity of the chemokine-chemokine receptor interaction endow this protein family with enormous signaling plasticity and complexity that are not fully understood at present. Chemokines were initially identified as essential regulators of homeostatic and inflammatory trafficking of innate and adaptive leucocytes from lymphoid organs to tissues. Chemokines also mediate the host response to cancer. Nevertheless, chemokine function in this response is not limited to regulating leucocyte infiltration into the tumor microenvironment. It is now known that chemokines and their receptors influence most-if not all-hallmark processes of cancer; they act on both neoplastic and untransformed cells in the tumor microenvironment, including fibroblasts, endothelial cells (blood and lymphatic), bone marrow-derived stem cells, and, obviously, infiltrating leucocytes. This review begins with an overview of chemokine and chemokine receptor structure, to better define how chemokines affect the proliferation, survival, stemness, and metastatic potential of neoplastic cells. We also examine the main mechanisms by which chemokines regulate tumor angiogenesis and immune cell infiltration, emphasizing the pro- and antitumorigenic activity of this protein superfamily in these interrelated processes.

ROS homeostasis and metabolism: a critical liaison for cancer therapy

Evidence indicates that hypoxia and oxidative stress can control metabolic reprogramming of cancer cells and other cells in tumor microenvironments and that the reprogrammed metabolic pathways in cancer tissue can also alter the redox balance. Thus, important steps toward developing novel cancer therapy approaches would be to identify and modulate critical biochemical nodes that are deregulated in cancer metabolism and determine if the therapeutic efficiency can be influenced by changes in redox homeostasis in cancer tissues. In this review, we will explore the molecular mechanisms responsible for the metabolic reprogramming of tumor microenvironments, the functional modulation of which may disrupt the effects of or may be disrupted by redox homeostasis modulating cancer therapy.

Molecular mechanisms of peritoneal dissemination in gastric cancer

Peritoneal dissemination represents a devastating form of gastric cancer (GC) progression with a dismal prognosis. There is no effective therapy for this condition. The 5-year survival rate of patients with peritoneal dissemination is 2%, even including patients with only microscopic free cancer cells without macroscopic peritoneal nodules. The mechanism of peritoneal dissemination of GC involves several steps: detachment of cancer cells from the primary tumor, survival in the free abdominal cavity, attachment to the distant peritoneum, invasion into the subperitoneal space and proliferation with angiogenesis. These steps are not mutually exclusive, and combinations of different molecular mechanisms can occur in each process of peritoneal dissemination. A comprehensive understanding of the molecular events involved in peritoneal dissemination is important and should be systematically pursued. It is crucial to identify novel strategies for the prevention of this condition and for identification of markers of prognosis and the development of molecular-targeted therapies. In this review, we provide an overview of recently published articles addressing the molecular mechanisms of peritoneal dissemination of GC to provide an update on what is currently known in this field and to propose novel promising candidates for use in diagnosis and as therapeutic targets.

CXCR4 and CCR7: Two eligible targets in targeted cancer therapy

Cancer is one of the most common cause of death in the world with high negative emotional, economic, and social impacts. Conventional therapeutic methods, including chemotherapy and radiotherapy, have not proven satisfactory and relapse is common in most cases. Recent studies have focused on targeted therapy with more precise identification and targeted attacks to the cancer cells. For this purpose, chemokine receptors are proper targets and among them, CXCR4 and CCR7, with a crucial role in cancer metastasis, are being considered as desired candidates for investigation. In this review paper, the most important experimental results are highlighted on the potential targeted therapies based on CXCR4 and CCR7 chemokine receptors.