Identifying Effective Biomarkers for Accurate Pancreatic Cancer Prognosis Using Statistical Machine Learning

Pancreatic cancer (PC) has one of the lowest survival rates among all major types of cancer. Consequently, it is one of the leading causes of mortality worldwide. Serum biomarkers historically correlate well with the early prognosis of post-surgical complications of PC. However, attempts to identify an effective biomarker panel for the successful prognosis of PC were almost non-existent in the current literature. The current study investigated the roles of various serum biomarkers including carbohydrate antigen 19-9 (CA19-9), chemokine (C-X-C motif) ligand 8 (CXCL-8), procalcitonin (PCT), and other relevant clinical data for identifying PC progression, classified into sepsis, recurrence, and other post-surgical complications, among PC patients. The most relevant biochemical and clinical markers for PC prognosis were identified using a random-forest-powered feature elimination method. Using this informative biomarker panel, the selected machine-learning (ML) classification models demonstrated highly accurate results for classifying PC patients into three complication groups on independent test data. The superiority of the combined biomarker panel (Max AUC-ROC = 100%) was further established over using CA19-9 features exclusively (Max AUC-ROC = 75%) for the task of classifying PC progression. This novel study demonstrates the effectiveness of the combined biomarker panel in successfully diagnosing PC progression and other relevant complications among Egyptian PC survivors.

COVID-19 and candiduria: an investigation of the risk factors and immunological aspects

Secondary fungal infections are frequently observed in COVID-19 patients. However, the occurrence of candiduria in these patients and its risk factors are underexplored. We evaluated the risk factors of candiduria in COVID-19 patients, including inflammatory mediators that could be used as prognostic markers. Clinical information, laboratory test results, and outcomes were collected from severely ill COVID-19 patients with and without candiduria. Candida species identification, antifungal susceptibility, and plasma inflammatory mediators' measurements were performed. Regression logistic and Cox regression model were used to evaluate the risk factors. A higher risk of longer hospitalization and mortality were observed in patients with candiduria compared to those with COVID-19 only. Candiduria was caused by Candida albicans, C. glabrata, and C. tropicalis. Isolates with intermediate susceptibility to voriconazole and resistant to caspofungin were identified. Classic factors such as the use of corticosteroids and antibacterials, the worsening of renal function, and hematological parameters (hemoglobin and platelets) were found to predispose to candiduria. The mediators IL-1β, IL-1ra, IL-2, CXCL-8, IL-17, IFN-γ, basic FGF, and MIP-1β were significantly increased in patients with COVID-19 and candiduria. Furthermore, IFN-γ, IL-1ra, and CXCL-8 were associated with the occurrence of candiduria in COVID-19 patients, whereas basic FGF, IL-1β, and CXCL-8 were associated with the risk of death in these patients. Classical and immunological factors were associated with worse prognosis among patients with COVID-19 and candiduria. Some mediators, especially CXCL-8, can be a reliable biomarker of fungal coinfection and may guide the diagnostic and the treatment of these patients.

CXCL-8 as a signature of severe Helicobacter pylori infection and a stimulator of stomach region-dependent immune response

Helicobacter pylori infection is involved in development of diverse gastro-pathologies. Our aim is to investigate potential signature of cytokines-chemokine levels (IL-17A, IL-1β, and CXCL-8) in H. pylori-infected patients and their impact on immune response in both corpus and antrum. Multivariate level analysis with machine learning model were carried out using cytokines/chemokine levels of infected Moroccan patients. In addition, Geo dataset was used to run enrichment analysis following CXCL-8 upregulation. Our analysis showed that combination of cytokines-chemokine levels allowed prediction of positive H. pylori density score with <5% of miss-classification error, with fundus CXCL-8 being the most important variable for this discrimination. Furthermore, CXCL-8 dependent expression profile was mainly associated to IL6/JAK/STAT3 signaling in the antrum, interferons alpha and gamma responses in the corpus and commonly induced transcriptional /proliferative activities. To conclude, CXCL-8 level might be a signature of Moroccan H. pylori-infected patients and an inducer of regional-dependent immune response at the gastric level. Larger trials must be carried out to validate the relevance of these results for diverse populations.

Expression analysis of grass carp Foxp3 and its biologic effects on CXCL-8 transcription in non-lymphoid cells

Teleost Forkhead box protein P3 (Foxp3) expression was discovered not only in regulatory T cells (Tregs) but also in other cells. Compared to the extensive study on its roles in lymphoid cells, the expression pattern and biological roles of Foxp3 in non-lymphoid cells have not been elucidated in both mammals and fish species. In the present study, grass carp Foxp3 (gcFoxp3) mRNA expression was detected in different cell types, showing that it has a moderate expression level in peripheral blood leukocytes (PBLs), head kidney leukocytes (HKLs) and grass carp fibroblast-like kidney cells (CIK cells). Interestingly, gcFoxp3 mRNA and protein expression could be significantly stimulated by polyinosinic-polycytidylic acid (poly I:C) in CIK cells, indicating its participation in poly I:C-induced immune response in non-lymphoid cells. To further investigate the function of gcFoxp3, its overexpression plasmid was constructed and transfected into CIK cells. After 24 h of transfection, grass carp C-X-C chemokine ligand (CXCL) 8 (gcCXCL-8) mRNA expression was elevated, implying the modulatory role of gcFoxp3 in gcCXCL-8 mRNA expression. This notion was further supported by the features of gcCXCL-8 promoter which contained a putative Foxp3 binding site at -2196 to -2190 region. Poly I:C or overexpression of gcFoxp3 obviously stimulated gcCXCL-8 promoter activity and deletion of gcFoxp3 binding region on the promoter abolished this stimulation, revealing that Foxp3 is pivotal for transcription of CXCL-8 induced by poly I:C. In conclusion, our results collectively demonstrate expression pattern of teleost Foxp3, and illuminate novel immune function of fish Foxp3 in regulating chemokine transcription in non-lymphoid cells.

A chemokine/chemokine receptor signature potentially predicts clinical outcome in colorectal cancer patients

BACKGROUND

Differential expression of chemokines/chemokine receptors in colorectal cancer (CRC) may enable molecular characterization of patients' tumors for predicting clinical outcome.

OBJECTIVE

To evaluate the prognostic ability of these molecules in a CRC cohort and the CRC TCGA-dataset.

METHODS

Chemokine (CXCL-12α, CXCL-12β, IL-17A, CXCL-8, GM-CSF) and chemokine receptor (CXCR-4, CXCR-7) transcripts were analyzed by RT-qPCR in 76 CRC specimens (normal: 27, tumor: 49; clinical cohort). RNA-Seq data was analyzed from the TCGA-dataset (n= 375). Transcript levels were correlated with outcome; analyses: univariate, multivariable, Kaplan-Meier.

RESULTS

In the clinical cohort, chemokine/chemokine receptor levels were elevated 3-10-fold in CRC specimens (P⩽ 0.004) and were higher in patients who developed metastasis (P= 0.03 - < 0.0001). CXCR-4, CXCR-7, CXCL-12α, CXCL-8, IL-17 and GM-CSF levels predicted metastasis (P⩽ 0.0421) and/or overall survival (OS; P⩽ 0.0373). The CXCR-4+CXCR-7+CXCL-12 marker (CXCR-4/7+CXCL-12 (α/b) signature) stratified patients into risk for metastasis (P= 0.0014; OR, 2.72) and OS (P= 0.0442; OR, 2.7); sensitivity: 86.67%, specificity: 97.06%. In the TCGA-dataset, the CXCR-4/7+CXCL-12 signature predicted metastasis (P= 0.011; OR, 2.72) and OS (P= 0.0006; OR: 4.04). In both datasets, the signature was an independent predictor of clinical outcome.

CONCLUSIONS

Results of 451 specimens from both cohorts reveal that the CXCR-4/7+CXCL-12 signature potentially predicts outcome in CRC patients and may allow earlier intervention.

Dectin-1-Mediated Pathway Contributes to Fusarium proliferatum-Induced CXCL-8 Release from Human Respiratory Epithelial Cells

Fusarium species are causative agents of human respiratory disorders and are distributed widely in our environment. Little is known of their interaction with human respiratory epithelial cells, which may contribute to allergic airway responses. In this study, we report on the release of C–X–C motif chemokine ligand 8 (CXCL-8) from human bronchial epithelial BEAS-2B cells upon stimulation with Fusarium proliferatum extracts. F. proliferatum-induced cytokine release from BEAS-2B cells was determined by cytokine array and CXCL-8 enzyme-linked immunosorbent assay (ELISA) kits. Blocking antibodies and signaling pathway inhibitors were employed to delineate cell surface receptors and signaling pathways participating in CXCL-8 release. F. proliferatum extracts induced the release of CXCL-8 in a time-dependent manner. The dectin-1 receptor ligands, curdlan and laminarin, reduced CXCL-8 release. Cells pre-treated with anti-Dectin-1 antibodies (2 µg/mL) decreased CXCL-8 release by 24%. Furthermore, F. proliferatum-stimulated CXCL-8 release was reduced by 32%, 53%–81%, 40% and 26% after BEAS-2B cells were pretreated with activation inhibitors of spleen tyrosine kinase (Syk)—piceatannol—, mitogen-activated protein kinases (MAPKs)—PD98059, U0126, SB202190, SP600125—, phosphatidylinositol-3-kinase (PI3K)—LY294002—and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB)—BAY117082—, respectively. These results suggest that Dectin-1-mediated activation of the Syk, MAPKs, PI3K and NF-κB signaling pathways contributes to F. proliferatum-stimulated CXCL-8 release from BEAS-2B cells and provides an important basis for developing novel therapeutic strategies in clinical allergy.

Neutrophil Elastase Differentially Regulates Interleukin 8 (IL-8) and Vascular Endothelial Growth Factor (VEGF) Production by Cigarette Smoke Extract

Inflammation by IL-8-induced neutrophil recruitment and apoptosis of epithelial cells by decreased expression of VEGF have been suggested as one of the complicated pathogenic mechanisms of chronic obstructive pulmonary disease (COPD). The role of neutrophil elastase (NE) in the development of COPD is also well known. However, little is known about how they interact. The objective of this study was to elucidate the effect of NE on cigarette smoke extract (CSE)-induced IL-8 and VEGF production and its molecular mechanism in bronchial epithelial cells. CSE increased both IL-8 and VEGF production in human bronchial epithelial cells (BEAS-2B). Although NE significantly enhanced CSE-induced IL-8 production, it suppressed VEGF production. This differential regulation was not CSE-specific. The effect of NE on IL-8 production, but not VEGF, was ERK-dependent. Interestingly, in contrast to decreased VEGF protein expression, NE accelerated VEGF transcription by CSE, suggesting post-translational modification. When cells were incubated with purified NE, it was detected in the cytoplasm, suggesting the intracellular translocation of NE. Furthermore, NE fragmented recombinant human VEGF in vitro but not recombinant human IL-8. These results indicate that VEGF down-regulation is due to direct degradation by NE, which is translocated into cells. Similar to in vitro cell experiments, elastase treatment increased CSE-induced IL-8; however, it suppressed VEGF production in bronchoalveolar lavage fluid of CSE-treated mice. Moreover, elastase treatment enhanced CSE-induced emphysema in mice. Considering the actions of IL-8 and VEGF, our results suggest that NE contributes to the pathogenesis of COPD by enhancing inflammation and apoptosis.

Neutrophil Elastase Differentially Regulates Interleukin 8 (IL-8) and Vascular Endothelial Growth Factor (VEGF) Production by Cigarette Smoke Extract

Inflammation by IL-8-induced neutrophil recruitment and apoptosis of epithelial cells by decreased expression of VEGF have been suggested as one of the complicated pathogenic mechanisms of chronic obstructive pulmonary disease (COPD). The role of neutrophil elastase (NE) in the development of COPD is also well known. However, little is known about how they interact. The objective of this study was to elucidate the effect of NE on cigarette smoke extract (CSE)-induced IL-8 and VEGF production and its molecular mechanism in bronchial epithelial cells. CSE increased both IL-8 and VEGF production in human bronchial epithelial cells (BEAS-2B). Although NE significantly enhanced CSE-induced IL-8 production, it suppressed VEGF production. This differential regulation was not CSE-specific. The effect of NE on IL-8 production, but not VEGF, was ERK-dependent. Interestingly, in contrast to decreased VEGF protein expression, NE accelerated VEGF transcription by CSE, suggesting post-translational modification. When cells were incubated with purified NE, it was detected in the cytoplasm, suggesting the intracellular translocation of NE. Furthermore, NE fragmented recombinant human VEGF in vitro but not recombinant human IL-8. These results indicate that VEGF down-regulation is due to direct degradation by NE, which is translocated into cells. Similar to in vitro cell experiments, elastase treatment increased CSE-induced IL-8; however, it suppressed VEGF production in bronchoalveolar lavage fluid of CSE-treated mice. Moreover, elastase treatment enhanced CSE-induced emphysema in mice. Considering the actions of IL-8 and VEGF, our results suggest that NE contributes to the pathogenesis of COPD by enhancing inflammation and apoptosis.

CXCL8, overexpressed in colorectal cancer, enhances the resistance of colorectal cancer cells to anoikis. Cancer Lett. 2015;361:22-32. [PMID: 25687885 DOI: 10.1016/j.canlet.2015.02.021]

Anoikis is a form of apoptosis which occurs when anchorage-dependent cells either show loss of adhesion or inappropriate adhesion. Only a few cancer cells that detach from the primary site of the tumor acquire the ability to resist anoikis and form metastasis. The mechanism underlying the resistance of colorectal cancer (CRC) cells to anoikis remains unclear. Interleukin-8 (alternatively known as CXCL8) is associated with CRC angiogenesis and progression. Here, we found that a high abundance of CXCL8 or TOPK strongly correlated with poor overall and disease-free survival of 186 patients with CRC. A combination of high CXCL8 and high TOPK expressions had the worst prognosis. We showed that CXCL8 expression was negatively correlated with anoikis in CRC cells. CXCL8 treatment enhanced the resistance of CRC cells to apoptosis, which was accompanied by the increase of TOPK, and the activation of AKT and ERK. Moreover, we demonstrated that the inhibition of either ERK or AKT by specific chemical inhibitors attenuated the CXCL8-mediated resistance to anoikis. Treatment with AKT inhibitor abolished the effects of CXCL8 on TOPK expression, suggesting that TOPK was downstream of AKT in the process of anoikis. Taken together, we demonstrated that CXCL8 is strongly implicated in the resistance of CRC cells to anoikis, and that the AKT, TOPK and ERK pathway may be a potential therapeutic target for CRC.

Sustained stabilization of Interleukin-8 mRNA in human macrophages

The mRNAs of most inflammatory mediators are short-lived due to AU-rich elements (AREs) in their 3'-untranslated regions. AREs ensure a low basal level of expression during homeostasis and a transient nature of expression during the inflammatory response. Here, we report that the mRNA of the pro-inflammatory chemokine IL-8, which contains an archetypal ARE, is unexpectedly constitutively abundant and highly stable in primary human monocytes and macrophages. Using the pre-monocyte-like THP-1 cell line that can differentiate into macrophage-like cells, we show that a low level of unstable IL-8 mRNA in undifferentiated cells (half-life<30 min) becomes constitutively elevated and the mRNA is dramatically stabilized in differentiated THP-1 cells with a half-life of more than 15 h similar to primary monocytes and macrophages. In contrast, the level and stability of TNF-α mRNA also containing an ARE is only slightly affected by differentiation; it remains low and unstable in primary macrophages and differentiated THP-1 cells with an estimated half-life of less than 20 min. This differentiation-dependent stabilization of IL-8 mRNA is p38 MAPK-independent and is probably coupled with reduced protein translation. Reporter assays in THP-1 cells suggest that the ARE alone is not sufficient for the constitutive stabilization in macrophage-like cells and imply an effect of the natural biogenesis of the transcript on the stabilization of the mature form. We present a novel, cell type-dependent sustained stabilization of an ARE-containing mRNA with similarities to situations found in disease.

Modulation of CXCL-8 expression in human melanoma cells regulates tumor growth, angiogenesis, invasion, and metastasis

CXCL-8, a chemokine secreted by melanoma and stromal cells, serves as a growth and angiogenic factor for melanoma progression. This study evaluated how modulation of CXCL-8 levels in melanoma cell lines with different tumorigenic and metastatic potentials affected multiple tumor phenotypes. A375P cells (CXCL-8 low expressor) were stably transfected with a CXCL-8 mammalian expression vector to overexpress CXCL-8, whereas A375SM cells (CXCL-8 high expressor) were transfected with a CXCL-8 antisense expression vector to suppress CXCL-8 expression. Subsequent cell proliferation, migration, invasion, and soft-agar colony formation were analyzed, and in vivo tumor growth and metastasis were evaluated using mouse xenograft models. Our data demonstrate that overexpression of CXCL-8 significantly enhanced primary tumor growth and lung metastasis, accompanied by increased microvessel density in vivo, as compared with vector control-transfected cells. We also observed increased clonogenic ability, growth, and invasive potential of CXCL-8 overexpressing cells in vitro. Knockdown of CXCL-8 using an antisense vector resulted in increased cell death and reduced tumor growth relative to control. Taken together, these data confirm that CXCL-8 expression plays a critical role in regulating multiple cellular phenotypes associated with melanoma growth and metastasis.