Secreted PLA2 induces proliferation in astrocytoma through the EGF receptor: another inflammation-cancer link

A longitudinal single-cell and spatial multiomic atlas of pediatric high-grade glioma

Pediatric high-grade glioma (pHGG) is an incurable central nervous system malignancy that is a leading cause of pediatric cancer death. While pHGG shares many similarities to adult glioma, it is increasingly recognized as a molecularly distinct, yet highly heterogeneous disease. In this study, we longitudinally profiled a molecularly diverse cohort of 16 pHGG patients before and after standard therapy through single-nucleus RNA and ATAC sequencing, whole-genome sequencing, and CODEX spatial proteomics to capture the evolution of the tumor microenvironment during progression following treatment. We found that the canonical neoplastic cell phenotypes of adult glioblastoma are insufficient to capture the range of tumor cell states in a pediatric cohort and observed differential tumor-myeloid interactions between malignant cell states. We identified key transcriptional regulators of pHGG cell states and did not observe the marked proneural to mesenchymal shift characteristic of adult glioblastoma. We showed that essential neuromodulators and the interferon response are upregulated post-therapy along with an increase in non-neoplastic oligodendrocytes. Through in vitro pharmacological perturbation, we demonstrated novel malignant cell-intrinsic targets. This multiomic atlas of longitudinal pHGG captures the key features of therapy response that support distinction from its adult counterpart and suggests therapeutic strategies which are targeted to pediatric gliomas.

Prognostic Value of Systemic Inflammation Score for Esophageal Cancer Patients Undergoing Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The link between inflammation and cancer survival has been the subject of substantial research. The goal of this review is to summarize the evidence on the prognostic value of systemic inflammation score (SIS) in esophageal cancer patients undergoing surgical intervention.

METHODS

PubMed, Scopus, Embase, and Web of Science were searched for relevant articles published until 30^th June 2022. We pooled adjusted data on overall survival (OS) and disease-free survival (DFS) using a random-effects meta-analysis model. The review was pre-registered on PROSPER (No. CRD42022340717).

RESULTS

Eight studies were included. All studies were conducted either in China or Japan. Six studies showed that patients with SIS of 1-2 had poor OS as compared to those with scores of 0 (HR:1.42 95% CI: 1.24, 1.62 I²=25%). SIS of 1 (HR:1.45 95% CI: 1.18, 1.78 I²=0%) and 2 (HR:1.94 95% CI: 1.49, 2.53 I²=0%) were also associated with poor OS. Two studies compared the SIS score of 2 vs 0-1. Meta-analysis indicated that poor OS was associated with SIS of 2 (HR:1.80 95% CI: 1.25, 2.58). Data from three studies showed that the SIS score did not predict DFS (HR:1.40 95% CI: 0.82, 2.39 I²=91%).

CONCLUSION

SIS can be a novel prognostic indicator for esophageal cancer patients undergoing surgical intervention. Higher SIS is associated with a poor OS, but it does not predict DFS. Future studies are needed to strengthen the current evidence.

Secretory phospholipase (sPLA2-IIA) regulates breast cancer stem cells differentiation and metastatic potential

Breast cancer is the second most cancer worldwide in females. The primary factor responsible for tumor recurrence is the presence of breast cancer stem cells (BCSCs), which escape the chemo-radiotherapy. In this study, we have investigated the role of Secretory phospholipase-A2 Group 2A (sPLA2-IIA) that is overexpressed in BCSCs of MCF7 and MDA-MB-231 breast cancer cell lines. Further, overexpression of sPLA2-IIA revealed an increased EGFR/JNK/c-JUN/c-FOS signaling in BCSCs, while sPLA2-IIA knockdown significantly reduced the percentage of BCSCs and decreased signaling in both the cell lines. Importantly, sPLA2-IIA knockdown showed differentiation of BCSCs. Strikingly, PET imaging showed a decreased metastatic potential of BCSCs. Our study revealed a novel role of sPLA2-IIA in regulating BCSCs, which play a crucial role in regulating the differentiation and metastatic potential of BCSCs.

Phospholipases in Gliomas: Current Knowledge and Future Perspectives from Bench to Bedside

Phospholipases are essential intermediaries that work as hydrolyzing enzymes of phospholipids (PLs), which represent the most abundant species contributing to the biological membranes of nervous cells of the healthy human brain. They generate different lipid mediators, such as diacylglycerol, phosphatidic acid, lysophosphatidic acid, and arachidonic acid, representing key elements of intra- and inter-cellular signaling and being involved in the regulation of several cellular mechanisms that can promote tumor progression and aggressiveness. In this review, it is summarized the current knowledge about the role of phospholipases in brain tumor progression, focusing on low- and high-grade gliomas, representing promising prognostic or therapeutic targets in cancer therapies due to their influential roles in cell proliferation, migration, growth, and survival. A deeper understanding of the phospholipases-related signaling pathways could be necessary to pave the way for new targeted therapeutic strategies.

Progranulin inhibits phospholipase sPLA2-IIA to control neuroinflammation

Mutations in the granulin (GRN) gene, resulting in haploinsufficiency of the progranulin (PGRN) protein, are a leading cause of frontotemporal lobar degeneration (FTLD) and PGRN polymorphisms are associated with Alzheimer's disease (AD) and Parkinson's disease (PD). PGRN is a key regulator of microglia-mediated inflammation but the mechanism is still unknown. Here we report that PGRN interacts with sPLA2-IIA, a secreted phospholipase involved in inflammatory responses, to downregulate sPLA2-IIA activities and levels. sPLA2-IIA expression modifies PGRN deficiency phenotypes in mice and sPLA2-IIA inhibition rescues inflammation and lysosomal abnormalities in PGRN deficient mice. Furthermore, FTLD patients with GRN mutations show increased levels of sPLA2-IIA in astrocytes. Our data support sPLA2-IIA as a critical target for PGRN and a novel therapeutic target for FTLD-GRN.

Synthesis and Significance of Arachidonic Acid, a Substrate for Cyclooxygenases, Lipoxygenases, and Cytochrome P450 Pathways in the Tumorigenesis of Glioblastoma Multiforme, Including a Pan-Cancer Comparative Analysis

Glioblastoma multiforme (GBM) is one of the most aggressive gliomas. New and more effective therapeutic approaches are being sought based on studies of the various mechanisms of GBM tumorigenesis, including the synthesis and metabolism of arachidonic acid (ARA), an omega-6 polyunsaturated fatty acid (PUFA). PubMed, GEPIA, and the transcriptomics analysis carried out by Seifert et al. were used in writing this paper. In this paper, we discuss in detail the biosynthesis of this acid in GBM tumors, with a special focus on certain enzymes: fatty acid desaturase (FADS)1, FADS2, and elongation of long-chain fatty acids family member 5 (ELOVL5). We also discuss ARA metabolism, particularly its release from cell membrane phospholipids by phospholipase A₂ (cPLA₂, iPLA₂, and sPLA₂) and its processing by cyclooxygenases (COX-1 and COX-2), lipoxygenases (5-LOX, 12-LOX, 15-LOX-1, and 15-LOX-2), and cytochrome P450. Next, we discuss the significance of lipid mediators synthesized from ARA in GBM cancer processes, including prostaglandins (PGE₂, PGD₂, and 15-deoxy-Δ^12,14-PGJ₂ (15d-PGJ₂)), thromboxane A₂ (TxA₂), oxo-eicosatetraenoic acids, leukotrienes (LTB₄, LTC₄, LTD₄, and LTE₄), lipoxins, and many others. These lipid mediators can increase the proliferation of GBM cancer cells, cause angiogenesis, inhibit the anti-tumor response of the immune system, and be responsible for resistance to treatment.

Can the systemic inflammation score be used to predict prognosis in gastric cancer patients undergoing surgery? A systematic review and meta-analysis

Background

Inflammatory markers are being increasingly used to predict the prognosis of cancer patients. We hereby conducted the first meta-analysis assessing the association between systemic inflammation score (SIS) and prognosis of gastric cancer patients undergoing surgical intervention.

Methods

A literature search was carried out on PubMed, CENTRAL, Scopus, and Embase up to 3rd June 2022 for relevant studies. Adjusted data reported as hazard ratios (HR) was combined in a random-effects model.

Results

A total of seven studies with 5,338 patients could be included. All studies were from either China or Japan and published in the last four years. Meta-analysis showed that higher SIS scores (1 or 2) were significant predictors of poor overall survival (OS) in gastric cancer patients (HR: 1.25 95% CI: 1.05, 1.49, I²= 11%). Similarly, the meta-analysis demonstrated that an SIS score of 2 was associated with poor OS as compared to scores of 0/1 (HR: 2.53 95% CI: 1.30, 4.89, I²= 45%). Data on disease-free survival (DFS) was scarce to draw conclusions.

Conclusion

The SIS score can be a simple and useful tool to predict OS in gastric cancer patients undergoing surgery. Data on DFS is scarce and conflicting. Future studies should report using standard reference groups and provide data on DFS to enhance current evidence.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/#searchadvanced, identifier: CRD42022335548.

Integrated analysis of inflammatory response subtype-related signature to predict clinical outcomes, immune status and drug targets in lower-grade glioma

Background: The inflammatory response in the tumor immune microenvironment has implications for the progression and prognosis in glioma. However, few inflammatory response-related biomarkers for lower-grade glioma (LGG) prognosis and immune infiltration have been identified. We aimed to construct and identify the prognostic value of an inflammatory response-related signature, immune infiltration, and drug targets for LGG.

Methods: The transcriptomic and clinical data of LGG samples and 200 inflammatory response genes were obtained from public databases. The LGG samples were separated into two inflammatory response-related subtypes based on differentially expressed inflammatory response genes between LGG and normal brain tissue. Next, inflammatory response-related genes (IRRGs) were determined through a difference analysis between the aforementioned two subtypes. An inflammatory response-related prognostic model was constructed using IRRGs by using univariate Cox regression and Lasso regression analyses and validated in an external database (CGGA database). ssGSEA and ESTIMATE algorithms were conducted to evaluate immune infiltration. Additionally, we performed integrated analyses to investigate the correlation between the prognostic signature and N 6-methyladenosine mRNA status, stemness index, and drug sensitivity. We finally selected MSR1 from the prognostic signature for further experimental validation.

Results: A total of nine IRRGs were identified to construct the prognostic signature for LGG. LGG patients in the high-risk group presented significantly reduced overall survival than those in the low-risk group. An ROC analysis confirmed the predictive power of the prognostic model. Multivariate analyses identified the risk score as an independent predictor for the overall survival. ssGSEA revealed that the immune status was definitely disparate between two risk subgroups, and immune checkpoints such as PD-1, PD-L1, and CTLA4 were significantly expressed higher in the high-risk group. The risk score was strongly correlated with tumor stemness and m6A. The expression levels of the genes in the signature were significantly associated with the sensitivity of tumor cells to anti-tumor drugs. Finally, the knockdown of MSR1 suppressed LGG cell migration, invasion, epithelial–mesenchymal transition, and proliferation.

Conclusion: The study constructed a novel signature composed of nine IRRGs to predict the prognosis, potential drug targets, and impact immune infiltration status in LGG, which hold promise for screening prognostic biomarkers and guiding immunotherapy for LGG.

Preoperative Systemic Immune–Inflammation Index (SII) as a Superior Predictor of Long-Term Survival Outcome in Patients With Stage I–II Gastric Cancer After Radical Surgery

Background

Systemic immune–inflammation index (SII), calculated by immunoinflammatory cell counts of peripheral blood, is considered a predictor of survival outcome in several solid tumors, including gastric cancer (GC). However, there is no study focusing on the prognostic value of SII in the early stage of GC. This study aims to compare prognostic prediction capabilities of several inflammatory indices, nutritional indices, and tumor markers to further verify the superior prognostic value of SII in stage I–II GC patients after surgery.

Methods

In this study, 548 patients (358 in the training group and 190 in the validation group) with stage I–II GC after radical surgery were retrospectively analyzed. The peripheral blood indices of interest were SII, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), advanced lung cancer inflammation index (ALI), systemic inflammation score (SIS), prognostic nutritional index (PNI), body mass index (BMI), albumin, carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), carbohydrate-associated antigen 19-9 (CA19-9), and alpha-fetoprotein (AFP). The time-dependent receiver operating characteristic (t-ROC) curves and the area under the curve (AUC) were used to determine the optimal cutoff value and prognostic ability of each parameter. Kaplan–Meier curves and multivariable Cox regression models were used to evaluate independent prognostic factors. The nomogram was constructed based on the result of bidirectional stepwise regression model.

Results

The optimal cutoff value of SII was 508.3. The 5-year overall survival rate of the low SII (SII-L) group was significantly higher than that of the high SII (SII-H) group (92% vs. 80%, P < 0.001), especially in the elderly and stage II patients (91% vs. 73%, P = 0.001; 86% vs. 67%, P = 0.003, respectively). The significant prognostic values of SII were consistent in most subgroups. In multivariate analysis, SII and CA19-9 were the only two independent prognostic hematology indices. The AUC value of SII (0.624) was greater than that of CA19-9 (0.528) and other prognostic parameters. Adding SII to the conventional model improved the predictive ability of 5-year overall survival as shown by the significantly increased net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (P = 0.033, P = 0.053, respectively) and modestly improved consistency index (C-index) (increased by 1.6%). External validation of SII-based nomogram demonstrated favorable predictive performance and discrimination. In addition, interactive web dynamic nomogram was published to facilitate clinical use.

Conclusion

SII is a simple but powerful index with a high predictive value to predict survival outcome in patients with stage I–II GC after radical operation. The SII-based nomogram can provide intuitive and accurate prognosis prediction of individual patients.

β-micrustoxin (Mlx-9), a PLA2 from Micrurus lemniscatus snake venom: biochemical characterization and anti-proliferative effect mediated by p53

Background

Endogenous phospholipases A₂ (PLA₂) play a fundamental role in inflammation, neurodegenerative diseases, apoptosis and cellular senescence. Neurotoxins with PLA₂ activity are found in snake venoms from the Elapidae and Viperidae families. The mechanism of action of these neurotoxins have been studied using hippocampal and cerebellar neuronal cultures showing [Ca²⁺]i increase, mitochondrial depolarization and cell death. Astrocytes are rarely used as a model, despite being modulators at the synapses and responsible for homeostasis and defense in the central nervous system. Preserving the cell division ability, they can be utilized to study the cell proliferation process. In the present work cultured astrocytes and glioblastoma cells were employed to characterize the action of β-micrustoxin (previously named Mlx-9), a PLA₂ isolated from Micrurus lemniscatus snake venom. The β-micrustoxin structure was determined and the cell proliferation, cell cycle phases and the regulatory proteins p53, p21 and p27 were investigated.

Methods

β-micrustoxin was characterized biochemically by a proteomic approach. Astrocytes were obtained by dissociation of pineal glands from Wistar rats; glioblastoma tumor cells were purchased from ATCC and Sigma and cultured in DMEM medium. Cell viability was evaluated by MTT assay; cell proliferation and cell cycle phases were analyzed by flow cytometry; p53, p21 and p27 proteins were studied by western blotting and immunocytochemistry.

Results

Proteomic analysis revealed fragments on β-micrustoxin that aligned with a PLA₂ from Micrurus lemniscatus lemniscatus previously identified as transcript ID DN112835_C3_g9_i1/m.9019. β-micrustoxin impaired the viability of astrocytes and glioblastoma tumor cells. There was a reduction in cell proliferation, an increase in G2/M phase and activation of p53, p21 and p27 proteins in astrocytes.

Conclusion

These findings indicate that β-micrustoxin from Micrurus lemniscatus venom could inhibit cell proliferation through p53, p21 and p27 activation thus imposing cell cycle arrest at the checkpoint G2/M.

Human Group IIA Phospholipase A2-Three Decades on from Its Discovery

Phospholipase A₂ (PLA₂) enzymes were first recognized as an enzyme activity class in 1961. The secreted (sPLA₂) enzymes were the first of the five major classes of human PLA₂s to be identified and now number nine catalytically-active structurally homologous proteins. The best-studied of these, group IIA sPLA₂, has a clear role in the physiological response to infection and minor injury and acts as an amplifier of pathological inflammation. The enzyme has been a target for anti-inflammatory drug development in multiple disorders where chronic inflammation is a driver of pathology since its cloning in 1989. Despite intensive effort, no clinically approved medicines targeting the enzyme activity have yet been developed. This review catalogues the major discoveries in the human group IIA sPLA₂ field, focusing on features of enzyme function that may explain this lack of success and discusses future research that may assist in realizing the potential benefit of targeting this enzyme. Functionally-selective inhibitors together with isoform-selective inhibitors are necessary to limit the apparent toxicity of previous drugs. There is also a need to define the relevance of the catalytic function of hGIIA to human inflammatory pathology relative to its recently-discovered catalysis-independent function.

The Change of Systemic Immune-Inflammation Index Independently Predicts Survival of Colorectal Cancer Patients after Curative Resection

Background

The systemic immune-inflammation index (SII) has an important role in predicting survival in some solid tumors. However, little information is available concerning the change of the SII (∆SII) in colorectal cancer (CRC) after curative resection. This study was designed to evaluate the role of ∆SII in CRC patients who received surgery.

Methods

A total 206 patients were enrolled in this study. Clinicopathologic characteristics and survival were assessed. The relationships between overall survival (OS), disease-free survival (DFS), and ∆SII were analyzed with both univariate Kaplan-Meier and multivariate Cox regression methods.

Results

Based on the patient data, the receiver operating characteristic (ROC) optimal cutoff value of ∆SII was 127.7 for OS prediction. The 3-year and 5-year OS rates, respectively, were 60.4% and 36.7% in the high-∆SII group (>127.7) and 87.6% and 79.8% in the low-∆SII group (≤127.7). The 3-year and 5-year DFS rates, respectively, were 54.1% and 34.1% in the high-∆SII group and 80.3% and 78.5% in the low-∆SII group. In the univariate analysis, smoking, pathological stages III-IV, high-middle degree of differentiation, lymphatic invasion, vascular invasion, and the high-ΔSII group were associated with poor OS. Adjuvant therapy, pathological stages III-IV, vascular invasion, and ΔSII were able to predict DFS. Multivariate analysis revealed that pathological stages III-IV (HR = 0.442, 95% CI = 0.236-0.827, p = 0.011), vascular invasion (HR = 2.182, 95% CI = 1.243-3.829, p = 0.007), and the high-ΔSII group (HR = 4.301, 95% CI = 2.517-7.350, p < 0.001) were independent predictors for OS. Adjuvant therapy (HR = 0.415, 95% CI = 0.250-0.687, p = 0.001), vascular invasion (HR = 3.305, 95% CI = 1.944-5.620, p < 0.001), and the high-ΔSII group (HR = 4.924, 95% CI = 2.992-8.102, p < 0.001) were significant prognostic factors for DFS.

Conclusions

The present study demonstrated that ∆SII was associated with the clinical outcome in CRC patients undergoing curative resection, supporting the role of ∆SII as a prognostic biomarker.

Phospholipase A2 superfamily in cancer

Phospholipase A2 enzymes (PLA₂s) comprise a superfamily that is generally divided into six subfamilies known as cytosolic PLA₂s (cPLA₂s), calcium-independent PLA₂s (iPLA₂s), secreted PLA₂s (sPLA₂s), lysosomal PLA₂s, platelet-activating factor (PAF) acetylhydrolases, and adipose specific PLA₂s. Each subfamily consists of several isozymes that possess PLA₂ activity. The first three PLA₂ subfamilies play important roles in inflammation-related diseases and cancer. In this review, the roles of well-studied enzymes sPLA₂-IIA, cPLA₂α and iPLA₂β in carcinogenesis and cancer development were discussed. sPLA₂-IIA seems to play conflicting roles and can act as a tumor suppressor or a tumor promoter according to the cancer type, but cPLA₂α and iPLA₂β play protumorigenic role in most cancers. The mechanisms of PLA₂-mediated signal transduction and crosstalk between cancer cells and endothelial cells in the tumor microenvironment are described. Moreover, the mechanisms by which PLA₂s mediate lipid reprogramming and glycerophospholipid remodeling in cancer cells are illustrated. PLA₂s as the upstream regulators of the arachidonic acid cascade are generally high expressed and activated in various cancers. Therefore, they can be considered as potential pharmacological targets and biomarkers in cancer. The detailed information summarized in this review may aid in understanding the roles of PLA₂s in cancer, and provide new clues for the development of novel agents and strategies for tumor prevention and treatment.

Prognostic Value of Preoperative Systemic Immune-Inflammation Index in Breast Cancer: A Propensity Score-Matching Study

Purpose: It was reported that the novel preoperative systemic immune-inflammation index (SII) can predict survival in cases of many malignant tumors. However, the prognostic significance of preoperative SII in breast cancer remains unclear. The purpose of this study was to investigate the relationship between SII and survival in breast cancer patients.

Methods: Breast cancer patients (1,026) who underwent a mastectomy at Sun Yat-sen University Cancer Center were retrospectively studied. The SII was determined using the following formula: neutrophil count × platelet count/lymphocyte count. The receiver operating characteristic (ROC) curve was used to determine the optimal cut-off value for SII. Propensity score matching (PSM) was applied to develop comparable cohorts of high SII group and low SII group.

Results: A total of 1,026 patients were included as the primary cohort, and 894 patients were matched and regarded as the matched cohort. Patients were divided into two groups based on SII value: SII <601.7 and high SII >601.7. In the primary cohort, the 5-years overall survival (OS), recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) rates for high SII group and low SII group were (85.6% vs. 91.3%, P = 0.016), (95.8% vs. 96.4%, P = 0.684), and (83.5% vs. 90.6%, P = 0.007), respectively. Univariate analysis showed that histological type, T stage, N stage, PR, HER2, Ki67, and SII all showed significant associations with OS; and histological type, T stage, N stage, and SII all showed significant associations with DMFS. Multivariate survival analysis revealed that SII can independently predict OS (P = 0.017) and DMFS (P = 0.007). Similar results were found in PSM cohort.

Conclusions: Preoperative SII may be a reliable predictor of OS and DMFS in patients with operable breast cancer to provide personalized prognostication and assist in formulation of the clinical treatment strategy.

Context-dependent effect of sPLA2-IIA induced proliferation on murine hair follicle stem cells and human epithelial cancer

BACKGROUND

Tissue stem cells (SCs) and cancer cells proliferation is regulated by many common signalling mechanisms. These mechanisms temporally balance proliferation and differentiation events during normal tissue homeostasis and repair. However, the effect of these aberrant signalling mechanisms on the ultimate fate of SCs and cancer cells remains obscure.

METHODS

To evaluate the functional effects of Secretory Phospholipase A₂-IIA (sPLA₂-IIA) induced abnormal signalling on normal SCs and cancer cells, we have used K14-sPLA₂-IIA transgenic mice hair follicle stem cells (HFSCs), DMBA/TPA induced mouse skin tumour tissues, human oral squamous cell carcinoma (OSCC) and skin squamous cell carcinoma (SCC) derived cell lines.

FINDINGS

Our study demonstrates that sPLA₂-IIA induces rapid proliferation of HFSCs, thereby altering the proliferation dynamics leading to a complete loss of the slow cycling H2BGFP positive HFSCs. Interestingly, in vivo reversion study by JNK inhibition exhibited a significant delay in post depilation hair growth, confirming that sPLA₂-IIA promotes HFSCs proliferation through JNK/c-Jun signalling. In a different cellular context, we showed increased expression of sPLA₂-IIA in human OSCC and mouse skin cancer tissues. Importantly, a xenograft of sPLA₂-IIA knockdown cells of OSCC and SCC cell lines showed a concomitant reduction of tumour volume in NOD-SCID mice and decreased JNK/c-Jun signalling.

INTERPRETATION

This study unravels how an increased proliferation induced by a common proliferation inducer (sPLA₂-IIA) alters the fate of normal SCs and cancer cells distinctively through common JNK/c-Jun signalling. Thus, sPLA₂-IIA can be a potential target for various diseases including cancer. FUND: This work was partly supported by the Indian Council of Medical Research (ICMR-3097) and ACTREC (42) grants.

Docosahexaenoic Acid Inhibits Proliferation of EoL-1 Leukemia Cells and Induces Cell Cycle Arrest and Cell Differentiation

Τhe effect of docosahexaenoic acid (DHA, an omega-3 polyunsaturated fatty acid) upon the proliferation of EoL-1 (Eosinophilic leukemia) cell line was assessed, while additional cellular events during the antiproliferative action were recorded. DHA inhibited EoL-1 cells growth dose-dependently by inducing growth arrest at G0/1 phase of the cell cycle. After DHA addition to the cells, the expression of MYC oncogene was decreased, PTAFR-mRNA overexpression was observed which was used as a marker of differentiation, and PLA2G4A-mRNA increase was recorded. The enzymatic activities of phospholipase A₂ (PLA₂), a group of hydrolytic enzymes, whose action precedes and leads to PAF biosynthesis through the remodeling pathway, as well as platelet activating factor acetylhydrolase (PAFAH) which hydrolyses and deactivates PAF, were also measured. DHA had an effect on the levels of both the intracellular and secreted activities of PLA₂ and PAFAH. The inflammatory cytokines IL-6 and TNF-α were also detected in high levels. In conclusion, DHA-induced EoL-1 cells differentiation was correlated with downregulation of MYC oncogene, overexpression of PTAFR and PLA2G4A-mRNAs, increase of the inflammatory cytokines production, and alteration of the enzymatic activities that regulate PAF levels. DHA is a natural substance and the understanding of its action on EoL-1 cells on molecular level could be useful in further investigation as a future therapeutic tool against F/P ⁺ hypereosinophilic syndrome.

Prognostic Gene Discovery in Glioblastoma Patients using Deep Learning

This study aims to discover genes with prognostic potential for glioblastoma (GBM) patients’ survival in a patient group that has gone through standard of care treatments including surgeries and chemotherapies, using tumor gene expression at initial diagnosis before treatment. The Cancer Genome Atlas (TCGA) GBM gene expression data are used as inputs to build a deep multilayer perceptron network to predict patient survival risk using partial likelihood as loss function. Genes that are important to the model are identified by the input permutation method. Univariate and multivariate Cox survival models are used to assess the predictive value of deep learned features in addition to clinical, mutation, and methylation factors. The prediction performance of the deep learning method was compared to other machine learning methods including the ridge, adaptive Lasso, and elastic net Cox regression models. Twenty-seven deep-learned features are extracted through deep learning to predict overall survival. The top 10 ranked genes with the highest impact on these features are related to glioblastoma stem cells, stem cell niche environment, and treatment resistance mechanisms, including POSTN, TNR, BCAN, GAD1, TMSB15B, SCG3, PLA2G2A, NNMT, CHI3L1 and ELAVL4.

Plasma phospholipase A2 activity may serve as a novel diagnostic biomarker for the diagnosis of breast cancer

Previous studies have indicated that phospholipase A2 (PLA2) may be associated with tumorigenesis in human tissues. The present study aimed to investigate the association between plasma PLA2 activity and the breast cancer (BC) status of patients. Increased plasma PLA2 activity was detected in patients with breast cancer when compared with healthy controls. Plasma samples were obtained from patients with BC (n=169), patients with benign disease (BD; n=80) and healthy controls (n=81). PLA2 activity was assessed using a quantitative fluorescent assay with selective inhibitors. It was demonstrated that increased PLA2 and secretory PLA2 (sPLA2) activity was associated with tumor stage, particularly in patients with late-stage disease. Additionally, smoking, alcohol consumption, body mass index (BMI) and age of patients did not have a significant effect on PLA2 activity. Analysis of receiver operating characteristic curves revealed that plasma PLA2 and sPLA2 activities were increased in BC patients compared with healthy controls. It was concluded that plasma PLA2 activity may serve as a biomarker for patients with BC.

Secretory phospholipase A2-IIA overexpressing mice exhibit cyclic alopecia mediated through aberrant hair shaft differentiation and impaired wound healing response

Secretory phospholipase A₂ Group-IIA (sPLA₂-IIA) is involved in lipid catabolism and growth promoting activity. sPLA₂-IIA is deregulated in many pathological conditions including various cancers. Here, we have studied the role of sPLA₂-IIA in the development of cyclic alopecia and wound healing response in relation to complete loss of hair follicle stem cells (HFSCs). Our data showed that overexpression of sPLA₂-IIA in homozygous mice results in hyperproliferation and terminal epidermal differentiation followed by hair follicle cycle being halted at anagen like stage. In addition, sPLA2-IIA induced hyperproliferation leads to complete exhaustion of hair follicle stem cell pool at PD28 (Postnatal day). Importantly, sPLA₂-IIA overexpression affects the hair shaft differentiation leading to development of cyclic alopecia. Molecular investigation study showed aberrant expression of Sox21, Msx2 and signalling modulators necessary for proper differentiation of inner root sheath (IRS) and hair shaft formation. Further, full-thickness skin wounding on dorsal skin of K14-sPLA₂-IIA homozygous mice displayed impaired initial healing response. Our results showed the involvement of sPLA₂-IIA in regulation of matrix cells differentiation, hair shaft formation and complete loss of HFSCs mediated impaired wound healing response. These novel functions of sPLA₂-IIA may have clinical implications in alopecia, cancer development and ageing.

Prognostic value of systemic immune-inflammation index in patients with gastric cancer

Background

Inflammation-based indexes have been used to predict survival and recurrence in cancer patients. Systemic immune-inflammation index (SII) was reported to be associated with prognosis in some malignant tumors. In the present study, we aimed to explore the association between SII and the prognosis of patients with gastric cancer.

Methods

We retrospectively analyzed data from 444 gastric cancer patients who underwent gastrectomy at the First Affiliated Hospital of Sun Yat-sen University between January 1994 and December 2005. Preoperative SII was calculated. The Chi square test or Fisher’s exact test was used to determine the relationship between preoperative SII and clinicopathologic characteristics. Overall survival (OS) rates were estimated using the Kaplan–Meier method, and the effect of SII on OS was analyzed using the Cox proportional hazards model. Receiver operating characteristic (ROC) curves were used to compare the predictive ability of SII, NLR, and PLR.

Results

SII equal to or higher than 660 was significantly associated with old age, large tumor size, unfavorable Borrmann classification, advanced tumor invasion, lymph node metastasis, distant metastasis, advanced TNM stage, and high carcino-embryonic antigen level, high neutrophil–lymphocyte ratio, and high platelet–lymphocyte ratio (all P < 0.05). High SII was significantly associated with unfavorable prognosis (P < 0.001) and SII was an independent predictor for OS (P = 0.015). Subgroups analysis further showed significant associations between high SII and short OS in stage I, II, III subgroups (all P < 0.05). SII was superior to NLR and PLR for predicting OS in patients with gastric cancer.

Conclusion

Preoperative SII level is an independent prognostic factor for OS in patients with gastric cancer.

Antitumoral effects of γCdcPLI, a PLA2 inhibitor from Crotalus durissus collilineatus via PI3K/Akt pathway on MDA-MB-231 breast cancer cell

Phospholipases A₂(PLA₂s) overexpression is closely associated with the malignant potential of breast cancers. Here, we showed for the first the antitumoral effects of γCdcPLI, a PLA₂ inhibitor from Crotalus durissus collilineatus via PI3K/Akt pathway on MDA-MB-231 cell. Firstly, γCdcPLI was more cytotoxic to MDA-MB-231 breast cancer cells than other cell lines (MCF-7, HeLa, PC3 and A549) and did not affect the viability of non-tumorigenic breast cell (MCF 10A). In addition, γCdcPLI induced modulation of important mediators of apoptosis pathways such as p53, MAPK-ERK, BIRC5 and MDM2. γCdcPLI decreased MDA-MB-231 adhesion, migration and invasion. Interestingly, the γCdcPLI also inhibited the adhesion and migration of endothelial cells and blocked angiogenesis by inhibiting tube formation by HUVECs in vitro and sprouting elongation on aortic ring assay ex vivo. Furthermore, γCdcPLI reduced the production of vascular endothelial growth factor (VEGF). γCdcPLI was also able to decrease PGE2 levels in MDA-MB-231 and inhibited gene and protein expression of the PI3K/Akt pathway. In conclusion, γCdcPLI showed in vitro antitumoral, antimestatatic and anti-angiogenic potential effects and could be an attractive approach for futures studies in cancer therapy.

Overexpression of secretory phospholipase A2-IIa supports cancer stem cell phenotype via HER/ERBB-elicited signaling in lung and prostate cancer cells

Resistance to conventional chemotherapies remains a significant clinical challenge in treatment of cancer. The cancer stem cells (CSCs) have properties necessary for tumor initiation, resistance to therapy, and progression. HER/ERBB‑elicited signaling supports CSC properties. Our previous studies revealed that secretory phospholipase A2 group IIa (sPLA2‑IIa) is overexpressed in both prostate and lung cancer cells, leading to an aberrant high level in the interstitial fluid, i.e., tumor microenvironment and blood. HER/ERBB-PI3K-Akt-NF-κB signaling stimulates sPLA2‑IIa overexpression, and in turn, sPLA2‑IIa activates EGFR family receptors and HER/ERBB-elicited signaling and stimulates sPLA2‑IIa overexpression in a positive feedback manner. The present study determined the molecular mechanisms of sPLA2‑IIa in stimulating HER/ERBB-elicited signaling and supporting CSC properties. We found that sPLA2‑IIa binds both EGFR and HER3 demonstrated by co-immunoprecipitation experiments and also indirectly interacts with HER2, suggesting that sPLA2‑IIa functions as a ligand for both EGFR and HER3. Furthermore, both side population CSCs from non-small cell lung cancer (NSCLC) A549 and H1975 cells and ALDH1‑high CSCs from castration-resistant prostate cancer (CRPC) 22Rv1 cells overexpress sPLA2‑IIa and produce tumors when inoculated into subcutis of nude mice. Given an aberrant high level of sPLA2‑IIa in the tumor microenvironment that should be much higher than that in the blood, our findings support the notion that sPLA2‑IIa functions as a ligand for EGFR family receptors and supports CSC properties via HER/ERBB-elicited signaling, which may contribute to resistance to therapy and cancer progression.

A dangerous liaison: Leptin and sPLA2-IIA join forces to induce proliferation and migration of astrocytoma cells

Glioblastoma, the most aggressive type of primary brain tumour, shows worse prognosis linked to diabetes or obesity persistence. These pathologies are chronic inflammatory conditions characterized by altered profiles of inflammatory mediators, including leptin and secreted phospholipase A₂-IIA (sPLA₂-IIA). Both proteins, in turn, display diverse pro-cancer properties in different cell types, including astrocytes. Herein, to understand the underlying relationship between obesity and brain tumors, we investigated the effect of leptin, alone or in combination with sPLA₂-IIA on astrocytoma cell functions. sPLA₂-IIA induced up-regulation of leptin receptors in 1321N1 human astrocytoma cells. Leptin, as well as sPLA₂-IIA, increased growth and migration in these cells, through activation/phosphorylation of key proteins of survival cascades. Leptin, at concentrations with minimal or no activating effects on astrocytoma cells, enhanced growth and migration promoted by low doses of sPLA₂-IIA. sPLA₂-IIA alone induced a transient phosphorylation pattern in the Src/ERK/Akt/mTOR/p70S6K/rS6 pathway through EGFR transactivation, and co-addition of leptin resulted in a sustained phosphorylation of these signaling regulators. Mechanistically, EGFR transactivation and tyrosine- and serine/threonine-protein phosphatases revealed a key role in this leptin-sPLA₂-IIA cross-talk. This cooperative partnership between both proteins was also found in primary astrocytes. These findings thus indicate that the adipokine leptin, by increasing the susceptibility of cells to inflammatory mediators, could contribute to worsen the prognosis of tumoral and neurodegenerative processes, being a potential mediator of some obesity-related medical complications.

sPLA2 -IIA Overexpression in Mice Epidermis Depletes Hair Follicle Stem Cells and Induces Differentiation Mediated Through Enhanced JNK/c-Jun Activation

Secretory phospholipase A2 Group-IIA (sPLA2 -IIA) catalyzes the hydrolysis of the sn-2 position of glycerophospholipids to yield fatty acids and lysophospholipids. sPLA2 -IIA is deregulated in various cancers; however, its role in hair follicle stem cell (HFSC) regulation is obscure. Here we report a transgenic mice overexpressing sPLA2 -IIA (K14-sPLA2 -IIA) showed depletion of HFSC pool. This was accompanied with increased differentiation, loss of ortho-parakeratotic organization and enlargement of sebaceous gland, infundibulum and junctional zone. The colony forming efficiency of keratinocytes was significantly reduced. Microarray profiling of HFSCs revealed enhanced level of epithelial mitogens and transcription factors, c-Jun and FosB that may be involved in proliferation and differentiation. Moreover, K14-sPLA2 -IIA keratinocytes showed enhanced activation of EGFR and JNK1/2 that led to c-Jun activation, which co-related with enhanced differentiation. Further, depletion of stem cells in bulge is associated with high levels of chromatin silencing mark, H3K27me3 and low levels of an activator mark, H3K9ac suggestive of alteration in gene expression contributing toward stem cells differentiation. Our results, first time uncovered that overexpression of sPLA2 -IIA lead to depletion of HFSCs and differentiation associated with altered histone modification. Thus involvement of sPLA2 -IIA in stem cells regulation and disease pathogenesis suggest its prospective clinical implications. Stem Cells 2016;34:2407-2417.

Phospholipase A2-Induced Remodeling Processes on Liquid-Ordered/Liquid-Disordered Membranes Containing Docosahexaenoic or Oleic Acid: A Comparison Study

Vesicle cycling, which is an important biological event, involves the interplay between membrane lipids and proteins, among which the enzyme phospholipase A2 (PLA2) plays a critical role. The capacity of PLA2 to trigger the budding and fission of liquid-ordered (L(o)) domains has been examined in palmitoyl-docosahexaenoylphosphatidylcholine (PDPC) and palmitoyl-oleoylphosphatidylcholine (POPC)/sphingomyelin/cholesterol membranes. They both exhibited a L(o)/liquid-disordered (L(d)) phase separation. We demonstrated that PLA2 was able to trigger budding in PDPC-containing vesicles but not POPC ones. The enzymatic activity, line tension, and elasticity of the membrane surrounding the L(o) domains are critical for budding. The higher line tension of Lo domains in PDPC mixtures was assigned to the greater difference in order parameters of the coexisting phases. The higher amount of lysophosphatidylcholine generated by PLA2 in the PDPC-containing mixtures led to a less-rigid membrane, compared to POPC. The more elastic L(d) membranes in PDPC mixtures exert a lower counteracting force against the L(o) domain bending.

Examination of Epigenetic and other Molecular Factors Associated with mda-9/Syntenin Dysregulation in Cancer Through Integrated Analyses of Public Genomic Datasets

mda-9/Syntenin (melanoma differentiation-associated gene 9) is a PDZ domain containing, cancer invasion-related protein. In this study, we employed multiple integrated bioinformatic approaches to identify the probable epigenetic factors, molecular pathways, and functionalities associated with mda-9 dysregulation during cancer progression. Analyses of publicly available genomic data (e.g., expression, copy number, methylation) from TCGA, GEO, ENCODE, and Human Protein Atlas projects led to the following observations: (a) mda-9 expression correlates with both copy number and methylation level of an intronic CpG site (cg1719774) located downstream of the CpG island, (b) cg1719774 methylation is a likely prognostic marker in glioma, (c) among 22 cancer types, melanoma exhibits the highest mda-9 level, and lowest level of methylation at cg1719774, (d) cg1719774 hypomethylation is also associated with histone modifications (at the mda-9 locus) indicative of more active transcription, (e) using Gene Set Enrichment Analysis (GSEA), and the Virtual Gene Overexpression or Repression (VIGOR) analytical scheme, we were able to predict mda-9's association with extracellular matrix organization (e.g., MMPs, collagen, integrins), IGFBP2 and NF-κB signaling pathways, phospholipid metabolism, cytokines (e.g., interleukins), CTLA-4, and components of complement cascade pathways. Indeed, previous publications have shown that many of the aforementioned genes and pathways are associated with mda-9's functionality.

Factors influencing the eicosanoids synthesis in vivo

External factors activate a sequence of reactions involving the reception, transduction, and transmission of signals to effector cells. There are two main phases of the body's reaction to harmful factors: the first aims to neutralize the harmful factor, while in the second the inflammatory process is reduced in size and resolved. Secondary messengers such as eicosanoids are active in both phases. The discovery of lipoxins and epi-lipoxins demonstrated that not all arachidonic acid (AA) derivatives have proinflammatory activity. It was also revealed that metabolites of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) such as resolvins, protectins, and maresins also take part in the resolution of inflammation. Knowledge of the above properties has stimulated several clinical trials on the influence of EPA and DHA supplementation on various diseases. However, the equivocal results of those trials prevent the formulation of guidelines on EPA and DHA supplementation. Prescription drugs are among the substances with the strongest influence on the profile and quantity of the synthesized eicosanoids. The lack of knowledge about their influence on the conversion of EPA and DHA into eicosanoids may lead to erroneous conclusions from clinical trials.

Secretory phospholipase A2-IIa upregulates HER/HER2-elicited signaling in lung cancer cells

Lung cancer is the leading cause of cancer death worldwide. There is an urgent need for early diagnostic tools and novel therapies in order to increase lung cancer survival. Secretory phospholipase A2 group IIa (sPLA2-IIa) is involved in inflammation, tumorigenesis and metastasis. We were the first to uncover that cancer cells secrete sPLA2‑IIa. sPLA2‑IIa is overexpressed in almost all specimens of human lung cancers examined and is significantly elevated in the plasma of lung cancer patients. High levels of plasma sPLA2-IIa are significantly associated with advanced stage and decreased overall cancer survival. In this study, we further showed that elevated HER/HER2‑PI3K-Akt-NF-κB signaling contributes to sPLA2-IIa overexpression in lung cancer cells. sPLA2-IIa in turn phosphorylates and activates HER2 and HER3 in a time- and dose‑dependent manner in lung cancer cells. The structure and sequence‑based docking analysis revealed that sPLA2-IIa β hairpin shares structural similarity with the corresponding EGF hairpin. sPLA2-IIa forms an extensive interface with EGFR and brings the two lobes of EGFR into an active conformation. sPLA2-IIa also enhances the NF-κB promoter activity. Anti-sPLA2-IIa antibody, but not the small molecule sPLA2-IIa inhibitor LY315920, significantly inhibits sPLA2‑IIa-induced activation of NF-κB promoter. Our findings support the notion that sPLA2-IIa functions as a ligand for the EGFR family of receptors leading to an elevated HER/HER2-elicited signaling. Plasma sPLA2-IIa can potentially serve as lung cancer biomarker and sPLA2‑IIa is a potential therapeutic target against lung cancer.

CCL20 induces migration and proliferation on breast epithelial cells

The communication between the tumor cells and the surrounding cells helps drive the process of tumor progression. Since the microenvironment of breast cancer includes CCL20 chemokine, the purpose of this study was to determine whether CCL20 modulates the physiology of healthy breast epithelial cells in areas adjacent to the tumor. Therefore, primary cultures of mammary cells taken from normal peritumoral areas were used. We assessed that breast cells expressed CCR6 CCL20 receptor. Using molecular (siRNA) and pharmacological (inhibitors) techniques, we found multiple signaling kinases to be activated by CCR6 and involved in CCL20-induced breast cell proliferation and migration. The binding of 10 ng/ml CCL20 to CCR6 induced cell migration whilst higher concentrations (from 15 to 25 ng/ml) led to cell proliferation. CCL20 controlled cell migration and MMP-9 expression by PKC-alpha that activated Src, which caused the activation of downstream Akt, JNK, and NF-kB pathways. Furthermore, higher CCL20 concentrations increased cycE and decreased p27Kip expression ending in enhanced cell proliferation. Cell proliferation occurred through PKC-epsilon activation that transactivated EGFR and ERK1/2/MAPK pathway. Although activated by different CCL20 concentrations, these pathways function in parallel and crosstalk to some extent, inasmuch as Akt activation was responsible for ERK1/2 nuclear translocation and enhanced the transcription of of c-fos and c-myc, involved in cell proliferation. In summary, tumor cells exchange signals with the surrounding healthy cells modifying the extracellular matrix through enzyme secretion; thus, CCL20 might be a factor involved in the ontogeny of breast carcinoma.

The carcinogenic liver fluke, Clonorchis sinensis: new assembly, reannotation and analysis of the genome and characterization of tissue transcriptomes

Clonorchis sinensis (C. sinensis), an important food-borne parasite that inhabits the intrahepatic bile duct and causes clonorchiasis, is of interest to both the public health field and the scientific research community. To learn more about the migration, parasitism and pathogenesis of C. sinensis at the molecular level, the present study developed an upgraded genomic assembly and annotation by sequencing paired-end and mate-paired libraries. We also performed transcriptome sequence analyses on multiple C. sinensis tissues (sucker, muscle, ovary and testis). Genes encoding molecules involved in responses to stimuli and muscle-related development were abundantly expressed in the oral sucker. Compared with other species, genes encoding molecules that facilitate the recognition and transport of cholesterol were observed in high copy numbers in the genome and were highly expressed in the oral sucker. Genes encoding transporters for fatty acids, glucose, amino acids and oxygen were also highly expressed, along with other molecules involved in metabolizing these substrates. All genes involved in energy metabolism pathways, including the β-oxidation of fatty acids, the citrate cycle, oxidative phosphorylation, and fumarate reduction, were expressed in the adults. Finally, we also provide valuable insights into the mechanism underlying the process of pathogenesis by characterizing the secretome of C. sinensis. The characterization and elaborate analysis of the upgraded genome and the tissue transcriptomes not only form a detailed and fundamental C. sinensis resource but also provide novel insights into the physiology and pathogenesis of C. sinensis. We anticipate that this work will aid the development of innovative strategies for the prevention and control of clonorchiasis.

Knockdown of secretory phospholipase A2 IIa reduces lung cancer growth in vitro and in vivo

OBJECTIVE

Group IIa secretory phospholipase A2 (sPLA2 IIa) plays a role in the malignant potential of several epithelial cancers. Nuclear factor kappa B (NF-κB) regulates cancer cell growth and is modulated by phospholipase activity in many cancer cells. We hypothesized that knockdown of sPLA2 in lung cancer cells would reduce cell proliferation and NF-κB activity in vitro and attenuate tumor growth in vivo.

METHODS

Two human non-small cell lung cancer cell lines (A549 and H358) were transduced with short hairpin RNA targeting sPLA2 group IIa. Quantitative reverse transcriptase-polymerase chain reaction and immunoblotting confirmed knockdown of sPLA2 IIa messenger RNA and protein, respectively. Cell proliferation was evaluated by the 5-bromo-2'-deoxyuridine DNA labeling assay. NF-κB phosphorylation was assayed by western blot. 1 × 10(6) of A549 or A549 sPLA2 knockdown cells were injected into the left flanks of nude mice (aged 6 to 8 weeks). Tumors were followed for 23 days, then removed and stained with hematoxylin and eosin, stained with Ki-67, and analyzed for sPLA2 IIa messenger RNA expression.

RESULTS

sPLA2 knockdown reduced NF-κB phosphorylation and tumor growth in vivo. A549 wild-type tumors grew twice as fast as knockdown tumors. Ki-67 staining was more prominent throughout the wild-type tumors compared with knockdown tumors. Explanted knockdown tumors maintained lower sPLA2 levels compared with wild-type, confirmed by reverse transcriptase-polymerase chain reaction.

CONCLUSIONS

Knockdown of sPLA2 IIa suppresses lung cancer growth in part by attenuating NF-κB activity. These findings justify further investigation into the cellular mechanisms of sPLA2 in lung cancer and its potential role as a therapeutic target.

Group IIa secretory phospholipase expression correlates with group IIa secretory phospholipase inhibition-mediated cell death in K-ras mutant lung cancer cells

OBJECTIVE

There are currently no targeted therapies against lung tumors with oncogenic K-ras mutations that are found in 25% to -40% of lung cancers and are characterized by their resistance to epidermal growth factor receptor inhibitors. The isozyme group IIa secretory phospholipase A(2) (sPLA(2)IIa) is a potential biomarker and regulator of lung cancer cell invasion; however, the relationship between K-ras mutations and sPLA(2)IIa has yet to be investigated. We hypothesize that sPLA(2)IIa modulates lung cancer cell growth in K-ras mutant cells and that sPLA(2)IIa expression in human lung tumors is increased in K-ras mutant tumors.

METHODS

Baseline sPLA(2)IIa expression in K-ras mutant lung cancer cell lines (A549, SW1573, H358, H2009) was assessed. Cells were treated with a specific sPLA(2)IIa inhibitor and evaluated for apoptosis and cell viability. Nuclear factor kappa-b (NF-κB) and extracellular signal-regulated kinase 1/2 activity were detected by Western blot. Human tumor samples were evaluated for sPLA(2)IIa mRNA expression by quantitative reverse-transcription polymerase chain reaction.

RESULTS

Cytotoxicity of sPLA(2)IIa inhibition correlates with sPLA(2)IIa expression. Apoptosis in response to sPLA(2) inhibition parallels attenuation in NF-κB activity. In addition, sPLA(2)IIa expression in human tumors correlates with squamous cell pathology and increasing stage of K-ras mutant lung tumors.

CONCLUSIONS

Baseline sPLA(2)IIa expression predicts response to sPLA(2)IIa inhibition in some K-ras mutant lung cancer cells. This finding is independent of p53 mutation status. Furthermore, squamous tumors and advanced-stage K-ras mutant tumors express more sPLA(2)IIa. These data support a role for sPLA(2)IIa as a potential global therapeutic target in the treatment of lung cancer.

Secreted phospholipase A2-IIA-induced a phenotype of activated microglia in BV-2 cells requires epidermal growth factor receptor transactivation and proHB-EGF shedding

BACKGROUND

Activation of microglia, the primary component of the innate immune response in the brain, is a hallmark of neuroinflammation in neurodegenerative disorders, including Alzheimer's disease (AD) and other pathological conditions such as stroke or CNS infection. In response to a variety of insults, microglial cells produce high levels of inflammatory cytokines that are often involved in neuronal injury, and play an important role in the recognition, engulfment, and clearance of apoptotic cells and/or invading microbes. Secreted phospholipase A2-IIA (sPLA2-IIA), an enzyme that interacts with cells involved in the systemic immune/inflammatory response, has been found up-regulated in the cerebrospinal fluid and brain of AD patients. However, despite several approaches, its functions in mediating CNS inflammation remain unknown. In the present study, the role of sPLA2-IIA was examined by investigating its direct effects on microglial cells.

METHODS

Primary and immortalized microglial cells were stimulated by sPLA2-IIA in order to characterize the cytokine-like actions of the phospholipase. The hallmarks of activated microglia analyzed include: mitogenic response, phagocytic capabilities and induction of inflammatory mediators. In addition, we studied several of the potential molecular mechanisms involved in those events.

RESULTS

The direct exposure of microglial cells to sPLA2-IIA stimulated, in a time- and dose-dependent manner, their phagocytic and proliferative capabilities. sPLA2-IIA also triggered the synthesis of the inflammatory proteins COX-2 and TNFα. In addition, EGFR phosphorylation and shedding of the membrane-anchored heparin-binding EGF-like growth factor (pro-HB-EGF) ectodomain, as well as a rapid activation/phosphorylation of the classical survival proteins ERK, P70S6K and rS6 were induced upon sPLA2-IIA treatment. We further demonstrated that the presence of an EGFR inhibitor (AG1478), a matrix metalloproteinase inhibitor (GM6001), an ADAM inhibitor (TAPI-1), and a HB-EGF neutralizing antibody abrogated the phenotype of activated microglia induced by the sPLA2-IIA.

CONCLUSION

These results support the hypothesis that sPLA2-IIA may act as a potent modulator of microglial functions through its ability to induce EGFR transactivation and HB-EGF release. Accordingly, pharmacological modulation of EGFR might be a useful tool for treating neuroinflammatory diseases characterized by sPLA2-IIA accumulation.