p38gamma MAPK cooperates with c-Jun in trans-activating matrix metalloproteinase 9

G-quadruplex structural dynamics at MAPK12 promoter dictates transcriptional switch to determine stemness in breast cancer

P38γ (MAPK12) is predominantly expressed in triple negative breast cancer cells (TNBC) and induces stem cell (CSC) expansion resulting in decreased survival of the patients due to metastasis. Abundance of G-rich sequences at MAPK12 promoter implied the functional probability to reverse tumorigenesis, though the formation of G-Quadruplex (G4) structures at MAPK12 promoter is elusive. Here, we identified two evolutionary consensus adjacent G4 motifs upstream of the MAPK12 promoter, forming parallel G4 structures. They exist in an equilibria between G4 and duplex, regulated by the binding turnover of Sp1 and Nucleolin that bind to these G4 motifs and regulate MAPK12 transcriptional homeostasis. To underscore the gene-regulatory functions of G4 motifs, we employed CRISPR-Cas9 system to eliminate G4s from TNBC cells and synthesized a naphthalene diimide (NDI) derivative (TGS24) which shows high-affinity binding to MAPK12-G4 and inhibits MAPK12 transcription. Deletion of G4 motifs and NDI compound interfere with the recruitment of the transcription factors, inhibiting MAPK12 expression in cancer cells. The molecular basis of NDI-induced G4 transcriptional regulation was analysed by RNA-seq analyses, which revealed that MAPK12-G4 inhibits oncogenic RAS transformation and trans-activation of NANOG. MAPK12-G4 also reduces CD44High/CD24Low population in TNBC cells and downregulates internal stem cell markers, arresting the stemness properties of cancer cells.

P38 kinase in gastrointestinal cancers

Gastrointestinal cancers are a leading cause of cancer morbidity and mortality worldwide with 4.2 million new cases and 3.2 million deaths estimated in 2020. Despite the advances in primary and adjuvant therapies, patients still develop distant metastases and require novel therapies. Mitogen‑activated protein kinase (MAPK) cascades are crucial signaling pathways that regulate many cellular processes, including proliferation, differentiation, apoptosis, stress responses and cancer development. p38 Mitogen Activated Protein Kinases (p38 MAPKs) includes four isoforms: p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). p38 MAPK was first identified as a stress response protein kinase that phosphorylates different transcriptional factors. Dysregulation of p38 pathways, in particular p38γ, are associated with cancer development, metastasis, autophagy and tumor microenvironment. In this article, we provide an overview of p38 and p38γ with respect to gastrointestinal cancers. Furthermore, targeting p38γ is also discussed as a potential therapy for gastrointestinal cancers.

p38γ MAPK Inflammatory and Metabolic Signaling in Physiology and Disease

p38γ MAPK (also called ERK6 or SAPK3) is a family member of stress-activated MAPKs and has common and specific roles as compared to other p38 proteins in signal transduction. Recent studies showed that, in addition to inflammation, p38γ metabolic signaling is involved in physiological exercise and in pathogenesis of cancer, diabetes, and Alzheimer's disease, indicating its potential as a therapeutic target. p38γphosphorylates at least 19 substrates through which p38γ activity is further modified to regulate life-important cellular processes such as proliferation, differentiation, cell death, and transformation, thereby impacting biological outcomes of p38γ-driven pathogenesis. P38γ signaling is characterized by its unique reciprocal regulation with its specific phosphatase PTPH1 and by its direct binding to promoter DNAs, leading to transcriptional activation of targets including cancer-like stem cell drivers. This paper will review recent findings about p38γ inflammation and metabolic signaling in physiology and diseases. Moreover, we will discuss the progress in the development of p38γ-specific pharmacological inhibitors for therapeutic intervention in disease prevention and treatment by targeting the p38γ signaling network.

The role of Actopaxin in tumor metastasis

Actopaxin is a newly discovered focal adhesions (FAs) protein, actin-binding protein and pseudopodia-enriched molecule. It can not only bind to a variety of FAs proteins (such as Paxillin, ILK and PINCH) and non-FAs proteins (such as TESK1, CdGAP, β2-adaptin, G3BP2, ADAR1 and CD29), but also participates in multiple signaling pathways. Thus, it plays a crucial role in regulating important processes of tumor metastasis, including matrix degradation, migration, and invasion, etc. This review covers the latest progress in the structure and function of Actopaxin, its interaction with other proteins as well as its involvement in regulating tumor development and metastasis. Additionally, the current limitations for Actopaxin related studies and the possible research directions on it in the future are also discussed. It is hoped that this review can assist relevant researchers to obtain a deep understanding of the role that Actopaxin plays in tumor progression, and also enlighten further research and development of therapeutic approaches for the treatment of tumor metastasis.

A network-based pharmacological investigation to identify the mechanistic regulatory pathway of andrographolide against colorectal cancer

Traditional cancer treatments have posed numerous obstacles, including toxicity, multiple drug resistance, and financial cost. On the contrary, bioactive phytochemicals used in complementary alternative medicine have recently increased attention due to their potential to modulate a wide range of molecular mechanisms with a less toxic effect. Therefore, we investigated the potential regulatory mechanisms of andrographolide to treat colorectal cancer (CRC) using a network pharmacology approach. Target genes of andrographolide were retrieved from public databases (PharmMapper, Swiss target prediction, Targetnet, STITCH, and SuperPred), while targets related to CRC were retrieved from disease databases (Genecards and DisGeNet) and expression datasets (GSE32323 and GSE8671) were retrieved from gene expression omnibus (GEO). Protein-protein interaction networks (PPI) were generated using STRING and Cytoscape, and hub genes were identified by topology analysis and MCODE. Annotation of target proteins was performed using Gene Ontology (GO) database DAVID and signaling pathway enrichment analysis using the Kyoto Encyclopedia and Genome Database (KEGG). Survival and molecular docking analysis for the hub genes revealed three genes (PDGFRA, PTGS2, and MMP9) were involved in the overall survival of CRC patients, and the top three genes with the lowest binding energy include PDGFRA, MET, and MAPK1. MET gene upregulation and PDGFRA and PTGS2 gene downregulation are associated with the survival of CRC patients, as revealed by box plots and correlation analysis. In conclusion, this study has provided the first scientific evidence to support the use of andrographolide to inhibit cellular proliferation, migration, and growth, and induce apoptosis by targeting the hub genes (PDGFRA, PTGS2, MMP9, MAPK1, and MET) involved in CRC migration and invasion.

Gondoic acid alleviates LPS‑induced Kupffer cells inflammation by inhibiting ROS production and PKCθ/ERK/STAT3 signaling pathway

Kupffer cells (KCs) is the main macrophage in liver, and its inflammation is related to liver diseases. It has been shown that inflammatory macrophages are accompanied by changes in monounsaturated fatty acid (MUFA) content. However, the effect of gondoic acid (GA) on inflammation and its underlying mechanism have not been described. In the current study, we demonstrated that GA significantly inhibited the expression of pro-inflammatory factors in LPS-exposed KCs. Further research found that GA reduced lipopolysaccharide (LPS)-stimulated reactive oxygen species (ROS) levels and enhanced the expression of antioxidant genes. Meanwhile, GA obviously blocked the LPS-stimulated PKCθ/ERK/STAT3 signaling pathways to alleviate the inflammatory responses. These results demonstrated for the first time that GA improves KCs inflammation through the inhibition of ROS production and PKCθ/ERK/STAT3 signaling pathway, the results assist in the potential development of functional foods or prodrugs based on the GA rich plant oils.

Stromal Cells Promote Matrix Deposition, Remodelling and an Immunosuppressive Tumour Microenvironment in a 3D Model of Colon Cancer

Simple Summary

Colorectal cancer is the third most common type of cancer in the world. Immune cells and normal supporting cells (MSCs) within a tumour affect patient survival and change how well treatments work. This research aimed to develop a more relevant 3D cancer model that combines MSCs and immune cells with cancer cells to test the effects of multiple cell types on tumour growth. We successfully developed a 3D model that shows that MSCs and immune cells can change the cancer-supporting environment around the tumour cells. We show that combining MSCs and immune cells with cancer cells can increase the level of immune-suppressing molecules they release and change immunotherapeutic drug targets on the cancer cells, similar to changes seen in human tumours. Using this 3D model for research may be better for testing new drugs than traditional 2D methods and could enable the identification of new drug targets.

Abstract

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. CRC develops in a complex tumour microenvironment (TME) with both mesenchymal stromal cells (MSCs) and immune infiltrate, shown to alter disease progression and treatment response. We hypothesised that an accessible, affordable model of CRC that combines multiple cell types will improve research translation to the clinic and enable the identification of novel therapeutic targets. A viable gelatine-methacrloyl-based hydrogel culture system that incorporates CRC cells with MSCs and a monocyte cell line was developed. Gels were analysed on day 10 by PCR, cytokine array, microscopy and flow cytometry. The addition of stromal cells increased transcription of matrix remodelling proteins FN1 and MMP9, induced release of tumour-promoting immune molecules MIF, Serpin E1, CXCL1, IL-8 and CXCL12 and altered cancer cell expression of immunotherapeutic targets EGFR, CD47 and PD-L1. Treatment with PD153035, an EGFR inhibitor, revealed altered CRC expression of PD-L1 but only in gels lacking MSCs. We established a viable 3D model of CRC that combined cancer cells, MSCs and monocytic cells that can be used to research the role the stroma plays in the TME, identify novel therapeutic targets and improve the transitional efficacy of therapies.

Comprehensive Analysis of the Expression and Prognosis for MMPs in Human Colorectal Cancer

Background

Previous study implicated that genes of matrix metalloproteinase (MMP) family play an important role in tumor invasion, neoangiogenesis, and metastasis. However, the diverse expression patterns and prognostic values of 24 MMPs in colorectal cancer are yet to be analyzed.

Methods

In this study, by integrating public database and our data, we first investigated the expression levels and protein levels of MMPs in patients with colorectal cancer. Then, by using TCGA and GEO datasets, we evaluated the association of MMPs with clinicopathological parameters and prognosis of colorectal cancer. Finally, by using the cBioPortal online tool, we analyzed the alterations of MMPs and did the network and pathway analyses for MMPs and their nearby genes.

Results

We found that, MMP1, MMP3, MMP7, MMP9–MMP12, and MMP14 were consistently upregulated in public dataset and our samples. Whereas, MMP28 was consistently downregulated in public dataset and our samples. In the clinicopathological analyses, upregulated MMP11, MMP14, MMP16, MMP17, MMP19, and MMP23B were significantly associated with a higher tumor stage. In the survival analyses, upregulated MMP11, MMP14, MMP17, and MMP19 were significantly associated with a shorter progression-free survival (PFS) time and a shorter relapse-free (RFS) time.

Discussion

This study implied that MMP11, MMP14, MMP17, and MMP19 are potential targets of precision therapy for patients with colorectal cancer.

The Role of p38γ in Cancer: From review to outlook

p38γ is a member of the p38 Mitogen Activated Protein Kinases (p38 MAPKs). It contains four subtypes in mammalian cells encoded by different genes including p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). Recent studies revealed that p38γ may exhibit a crucial role in tumorigenesis and cancer aggressiveness. Despite the large number of published literatures, further researches are demanded to clarify its role in cancer development, the tissue-specific function and associated novel treatment strategies. In this article, we provide the latest view on the connection between p38γ and malignant tumors, highlighting the function of p38γ. The clinical value of p38γ is also discussed, helping the translation into the remarkable therapeutic strategy in tumor diseases.

Assessment of clinical variables as predictive markers in the development and progression of colorectal cancer

Colorectal cancer (CRC) is graded as one of the most common cancer. It accounts for the second leading cause of cancer deaths worldwide. The present study intends to investigate the role and importance of different biochemical variables in the development of colorectal cancer.

In this cross-sectional study we recruited ninety-one patients diagnosed with colorectal cancer and fifty-three age-sex matched controls from June 2017 to June 2018. Different variables i.e. SOD, GSH, CAT, MDA, TGF, VEGF, TNF, ILs, MMPs, etc., were estimated with the help of their respective methods. Our findings suggest a significant increase in the levels of different inflammatory and stress-related markers. The NFκB, TGF-β, VEGFβ, 8OHdG, IsoP-2α were significantly found to be increased in patients with colon cancer (0.945 ± 0.067 μg/ml, 18.59 ± 1.53 pg/ml, 99.35 ± 4.29 pg/ml, 21.26 ± 1.29 pg/ml, 102.25 ± 4.25 pg/ml) as compared to controls (0.124 ± 0.024 μg/ml, 8.26 ± 0.88 pg/ml, 49.58 ± 2.62 pg/ml, 0.93 ± 0.29 pg/ml, 19.65 ± 3.19 pg/ml). Notably, the levels of different antioxidants were shown to be significantly lower in patients of colon cancer. The present study concluded that excessive oxidative stress and lipid peroxidation result in a decrease in the antioxidative capacity of cells which may influence diverse signaling cascades including NF-KB, which results in DNA modification and gene transcription that ultimately involved in the progression of colon cancer.

TNM staging for GIT cancers is correlated with the level of MMPs and TGF-β1

Gastrointestinal (GIT) cancers represent the third common cancers worldwide, characterized by rapid progression and higher mortality rate. Matrix metalloproteinases (MMPs) play an important role in cancer metastases. The present study was conducted to estimate and evaluate the role of MMP-7, -9, -10 and -12 and TGF β1 along with conventional biomarkers (CEA and CA19-9) in gastric (GC), pancreatic (PC) and colorectal cancer (CRC) staging system according to tumor size (T), included lymph node (N) and metastasis (M). Seventy-five patients were divided into GC group (n = 25), PC group (n = 25), CRC group (n = 25) and twenty-five healthy subjects (control group). Serum levels of MMP-7, -10 and -12 were assayed simultaneously using luminex multiplex technique. Also, MMP-9, TGF-β1, CA19-9 and CEA were determined by ELISA. MMP-7,-9,-10, -12, TGF-β1 and CEA levels were significantly (p < 0.001) higher in GIT cancer groups compared with control. CA19-9 was significantly (p < 0.001) higher in PC and CRC groups compared with control. MMP-9 was positively correlated with TNM staging in PC patients. MMP-12 was negatively correlated with T in PC and positively correlated with M in CRC group. CA 19-9 was positively correlated with M grade in CRC. Depending on the estimated cutoff values of area under receiver curve; CA19-9 and MMP-7 were excellent diagnostic markers in PC, CEA and MMP-7 were excellent in CRC, and MMP-7 and MMP-9 were excellent in GC. Our findings indicated the clinical utility of MMPs in diagnosis and TNM staging of GIT cancers along with CEA and CA19-9.

DNMT1 and p38γ are inversely expressed in reactive non‐metastatic lymph nodes burdened with colorectal adenocarcinoma

Lymph nodes are important front‐line defense immune tissues, which also act against inflammatory diseases and cancer. Lymph nodes undergo extensive upheavals within newly formed germinal centers (GCs) when exposed to antigens, the molecular mechanisms of which remain elusive. Recently, p38γ was identified as an important target for multiple cancers, including cutaneous T‐cell lymphoma (CTCL). We previously observed that p38γ is overexpressed in CTCL versus normal cells, but it is not clear if p38γ is expressed in B or T lymphocytes of GCs of patients in response to a stress such as cancer. Therefore, in this study, we obtained non‐metastatic reactive lymph nodes adjacent to cancer lesions (colorectal adenocarcinoma), then performed multicolor immunohistochemical staining for p38γ and other relevant markers. We observed for the first time that p38γ was expressed in the light zone of activated B cells and T helper cells in GCs, whereas DNA‐methyltransferase 1 (DNMT1), a marker for GC B cells, was highly expressed in centrocytes and in the dark zone of GCs. This inverse relationship suggests a novel function for p38γ in T cells that cross‐talk to B cells in response to stress.

Role of extra cellular proteins in gastric cancer progression and metastasis: an update

Background

Gastric cancer (GC) is one of the most common cancers in the world with a high ratio of mortality. Regarding the late diagnosis, there is a high ratio of distant metastasis among GC cases. Despite the recent progresses in therapeutic modalities, there is not still an efficient therapeutic method to increase survival rate of metastatic GC cases.

Main body

Apart from the various intracellular signaling pathways which are involved in tumor cell migration and metastasis, the local microenvironment is also a critical regulator of tumor cell migration. Indeed, the intracellular signaling pathways also exert their final metastatic roles through regulation of extra cellular matrix (ECM). Therefore, it is required to assess the role of extra cellular components in biology of GC.

Conclusion

In the present review, we summarize 48 of the significant ECM components including 17 ECM modifying enzymes, seven extracellular angiogenic factors, 13 cell adhesion and cytoskeletal organizers, seven matricellular proteins and growth factors, and four proteoglycans and extra cellular glycoproteins. This review paves the way of determination of a specific extra cellular diagnostic and prognostic panel marker for the GC patients.

Fractalkine Regulates HEC-1A/JEG-3 Interaction by Influencing the Expression of Implantation-Related Genes in an In Vitro Co-Culture Model

Embryo implantation is a complex process regulated by a network of biological molecules. Recently, it has been described that fractalkine (CX3CL1, FKN) might have an important role in the feto-maternal interaction during gestation since the trophoblast cells express fractalkine receptor (CX3CR1) and the endometrium cells secrete fractalkine. CX3CR1 controls three major signalling pathways, PLC-PKC pathway, PI3K/AKT/NFκB pathway and Ras-mitogen-activated protein kinases (MAPK) pathways regulating proliferation, growth, migration and apoptosis. In this study, we focused on the molecular mechanisms of FKN treatment influencing the expression of implantation-related genes in trophoblast cells (JEG-3) both in mono-and in co-culture models. Our results reveal that FKN acted in a concentration and time dependent manner on JEG-3 cells. FKN seemed to operate as a positive regulator of implantation via changing the action of progesterone receptor (PR), activin receptor and bone morphogenetic protein receptor (BMPR). FKN modified also the expression of matrix metalloproteinase 2 and 9 controlling invasion. The presence of HEC-1A endometrial cells in the co-culture contributed to the effect of fractalkine on JEG-3 cells regulating implantation. The results suggest that FKN may contribute to the successful attachment and implantation of embryo.

MKK3 sustains cell proliferation and survival through p38DELTA MAPK activation in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide and understanding its underlying molecular mechanisms is crucial for the development of therapeutic strategies. The mitogen-activated protein kinase-kinase 3 (MKK3) is a specific activator of p38 MAP kinases (p38 MAPKs), which contributes to the regulation of several cellular functions, such as proliferation, differentiation, apoptosis as well as response to drugs. At present, the exact MKK3/p38 MAPK pathway contribution in cancer is heavily debated because of its pleiotropic function. In this work, we retrospectively explored the prognostic and pathobiologic relevance of MKK3 in a cohort of CRC patients and assessed MKK3 molecular functions in a panel of CRC lines and colonocytes primary cultures. We found increased MKK3 levels in late-stage CRC patients which correlated with shorter overall survival. Herein, we report that the MKK3 targeting by inducible RNA interference univocally exerts antitumor effects in CRC lines but not in primary colonocytes. While MKK3 depletion per se affects growth and survival by induction of sustained autophagy and death in some CRC lines, it potentiates response to chemotherapeutic drug 5-fluorouracil (5-FU) in all of the tested CRC lines in vitro. Here, we demonstrate for the first time that in CRC the MKK3 specifically activates p38delta MAPK isoform to sustain prosurvival signaling and that such effect is exacerbated upon 5-FU challenge. Indeed, p38delta MAPK silencing recapitulates MKK3 depletion effects in CRC cells in vitro and in vivo. Overall, our data identified a molecular mechanism through which MKK3 supports proliferation and survival signaling in CRC, further supporting MKK3 as a novel and extremely attractive therapeutic target for the development of promising strategies for the management of CRC patients.

Insulin receptor substrate 2 (IRS2) deficiency delays liver fibrosis associated with cholestatic injury

Insulin receptor substrate 2 (IRS2) is a key downstream mediator of insulin and insulin-like growth factor 1 (IGF1) signalling pathways and plays a major role in liver metabolism. The aim of this study was to investigate whether IRS2 had an impact on the hepatic fibrotic process associated with cholestatic injury. Bile duct ligation (BDL) was performed in wild-type (WT) and Irs2-deficient (IRS2KO) female mice. Histological and biochemical analyses, together with fibrogenic and inflammatory responses were evaluated in livers from mice at 3, 7 and 28 days following BDL. We also explored whether activation of human hepatic stellate cells (HSCs) induced by IGF1 was modulated by IRS2. IRS2KO mice displayed reduced disruption of liver histology, such hepatocyte damage and excess deposition of extracellular matrix components, compared with WT mice at 3 and 7 days post-BDL. However, no histological differences between genotypes were found at 28 days post-BDL. The less pro-inflammatory profile of bile acids accumulated in the gallbladder of IRS2KO mice after BDL corresponded with the reduced expression of pro-inflammatory markers in these mice. Stable silencing of IRS2 or inhibition of ERK1/2 reduced the activation of human LX2 cells and also reduced induction of MMP9 upon IGF1 stimulation. Furthermore, hepatic MMP9 expression was strongly induced after BDL in WT mice, but only a slight increase was found in mice lacking IRS2. Our results have unravelled the signalling pathway mediated by IGF1R–IRS2–ERK1/2–MMP9 as a key axis in regulating HSC activation, which might be therapeutically relevant for targeting liver fibrosis.

Summary: IRS2 is a key mediator of IGF1R signalling in hepatic stellate cell activation in cholestatic liver injury.

Proteomics analysis of HSV-1-induced alterations in mouse brain microvascular endothelial cells

Herpes simplex virus 1 (HSV-1) is a predominant cause of herpes simplex encephalitis (HSE), leading to a high mortality rate and severe neurological sequelae worldwide. HSE is typically accompanied by the blood-brain barrier (BBB) disruption, but the underlying mechanisms are unclear. To explore the disruption mechanisms of the BBB, quantitative analysis of the cellular proteome was carried out to investigate the proteomic changes that occur after infection. In this study, bEnd.3 cells were infected with HSV-1, followed by liquid chromatography-tandem mass spectrometry. A total of 6761 proteins were identified in three independent mass spectrometry analyses. Compared to the uninfected cells, 386 and 293 differentially expressed proteins were markedly upregulated or downregulated, respectively. Bioinformatic analysis showed that the activator protein-1 factor, including Fos, Jun, and ATF family proteins and cell adhesion molecules were significantly changed. Further validation of the changes observed for these proteins was carried out by western blotting and quantitative real-time PCR. Transendothelial electrical resistance (TEER) studies were performed to explore the effects of ATF3, Fra1, or JunB overexpression on the function of bEnd.3 cells. Characterization of the differential expression of these proteins in bEnd.3 cells will facilitate further exploration of BBB disruption upon HSV-1 infection.

Assessment and clinicopathological correlation of matrix metalloproteinase 9 expression in nasopharyngeal carcinoma

INTRODUCTION

Nasopharyngeal cancer is not a common disease in most parts of the world. In India also, nasopharyngeal carcinoma (NPC) is not a common cancer, except for the Northeastern region of the country. Expression of matrix metalloproteinase 9 (MMP9) in the tumor cells is related to tumor invasion and metastasis. The aim of the present study is to analyze the expression of MMP9 in NPC and evaluate its prognostic implications.

MATERIALS AND METHODS

A total of 32 histologically confirmed tissue samples of NPC were examined by immunohistochemical staining to assess the expression of MMP9. Clinicopathological parameters and levels of MMP9 expression in the tumor tissue were analyzed using Chi-square test. Survival analysis was done using the Kaplan-Meier method and was compared using log-rank test. P <0.05 was considered statistically significant.

RESULTS

Of the 32 tissue samples of NPC, 23 (71.9%) were male and 9 (28.1%) were female. 7 (21.9%) patients presented in T1 Stage, 8 (25.0%) in T2, 12 (37.5%) in T3, and 5 (15.6%) in T4 Stages, respectively. 29 (90.6%) patients presented with lymph node metastasis. MMP9 expression level was significantly correlated with patient's age (P = 0.033), tumor histology (P = 0.017), tumor stage (P = 0.021), and lymph node metastasis (P = 0.011). The 5-year overall survival is higher for low-level expression as compared to high-level expression of MMP9 (P = 0.046).

CONCLUSION

MMP9 is an important prognostic factor for NPC. High expression of MMP9 is associated with cervical lymph nodes metastasis and poor survival outcome.

MicroRNA-570 is a novel regulator of cellular senescence and inflammaging

Diseases of accelerated aging often occur together (multimorbidity), and their prevalence is increasing, with high societal and health care costs. Chronic obstructive pulmonary disease (COPD) is one such condition, in which one half of patients exhibit ≥4 age-related diseases. Diseases of accelerated aging share common molecular pathways, which lead to the detrimental accumulation of senescent cells. These senescent cells no longer divide but release multiple inflammatory proteins, known as the senescence-associated secretory phenotype, which may perpetuate and speed disease. Here, we show that inhibiting miR-570-3p, which is increased in COPD cells, reverses cellular senescence by restoring the antiaging molecule sirtuin-1. MiR-570-3p is induced by oxidative stress in airway epithelial cells through p38 MAP kinase-c-Jun signaling and drives senescence by inhibiting sirtuin-1. Inhibition of elevated miR-570-3p in COPD small airway epithelial cells, using an antagomir, restores sirtuin-1 and suppresses markers of cellular senescence (p16INK4a, p21Waf1, and p27Kip1), thereby restoring cellular growth by allowing progression through the cell cycle. MiR-570-3p inhibition also suppresses the senescence-associated secretory phenotype (matrix metalloproteinases-2/9, C-X-C motif chemokine ligand 8, IL-1β, and IL-6). Collectively, these data suggest that inhibiting miR-570-3p rejuvenates cells via restoration of sirtuin-1, reducing many of the abnormalities associated with cellular senescence.-Baker, J. R., Vuppusetty, C., Colley, T., Hassibi, S., Fenwick, P. S., Donnelly, L. E., Ito, K., Barnes, P. J. MicroRNA-570 is a novel regulator of cellular senescence and inflammaging.

Inhibition of cell migration and invasion and promotion of cell apoptosis by overexpression of programmed cell death 4 (PDCD4) in cervical cancer Siha cells

Cervical cancer has been one of the leading causes of cancer-related deaths among women worldwide. However, few targeted drugs have been developed because of the poor understanding about the mechanisms of cervical cancer. A growing number of studies in recent years have shown that programmed cell death 4 (PDCD4), a new tumor suppressor, participates in the tumorigenesis and progression of various cancers. In this study, we investigated the influence of PDCD4 on cell migration, invasion, and apoptosis of cervical cancer cells. Siha cervical cancer cells were transfected with a recombinant lentivirus vector carrying the complete length of the PDCD4 gene and the normal controlled vector respectively and screened by puromycin. The expression of the mRNA and protein of PDCD4 were significantly elevated in Siha cells transfected with the recombinant vector carrying the PDCD4 gene. Then the overexpression of PDCD4 suppressed the cell migration and invasion in transwell migration and matrigel invasion assays respectively. Moreover, the overexpression of PDCD4 increased the proportion of cell apoptosis in flow cytometry analysis. In a multiple signal pathways assay, the upregulation of PDCD4 promoted the phosphorylation of some key proteins, such as p53 and STAT1. These results suggest that PDCD4 is a potential therapeutic target for cervical cancer.

Targeting an oncogenic kinase/phosphatase signaling network for cancer therapy

Protein kinases and phosphatases signal by phosphorylation and dephosphorylation to precisely control the activities of their individual and common substrates for a coordinated cellular outcome. In many situations, a kinase/phosphatase complex signals dynamically in time and space through their reciprocal regulations and their cooperative actions on a substrate. This complex may be essential for malignant transformation and progression and can therefore be considered as a target for therapeutic intervention. p38γ is a unique MAPK family member that contains a PDZ motif at its C-terminus and interacts with a PDZ domain-containing protein tyrosine phosphatase PTPH1. This PDZ-coupled binding is required for both PTPH1 dephosphorylation and inactivation of p38γ and for p38γ phosphorylation and activation of PTPH1. Moreover, the p38γ/PTPH1 complex can further regulate their substrates phosphorylation and dephosphorylation, which impacts Ras transformation, malignant growth and progression, and therapeutic response. This review will use the p38γ/PTPH1 signaling network as an example to discuss the potential of targeting the kinase/phosphatase signaling complex for development of novel targeted cancer therapy.

Discovery of phenylsulfonylfuroxan derivatives as gamma globin inducers by histone acetylation

N-oxide derivatives 5(a-b), 8(a-b), and 11(a-c) were designed, synthesized and evaluated in vitro and in vivo as potential drugs that are able to ameliorate sickle cell disease (SCD) symptoms. All of the compounds demonstrated the capacity to releasing nitric oxide at different levels ranging from 0.8 to 30.1%, in vivo analgesic activity and ability to reduce TNF-α levels in the supernatants of monocyte cultures. The most active compound (8b) protected 50.1% against acetic acid-induced abdominal constrictions, while dipyrone, which was used as a control only protected 35%. Compounds 8a and 8b inhibited ADP-induced platelet aggregation by 84% and 76.1%, respectively. Both compounds increased γ-globin in K562 cells at 100 μM. The mechanisms involved in the γ-globin increase are related to the acetylation of histones H3 and H4 that is induced by these compounds. In vitro, the most promising compound (8b) was not cytotoxic, mutagenic and genotoxic.

Insights of Crosstalk between p53 Protein and the MKK3/MKK6/p38 MAPK Signaling Pathway in Cancer

TP53 is universally recognized as a pivotal protein in cell-cycle fate and apoptotic induction and, unsurprisingly, it is one of the most commonly hijacked control mechanisms in cancer. Recently, the kinase MKK3 emerged as a potential therapeutic target in different types of solid tumor being linked to mutant p53 gain-of-function. In this review, we summarize the delicate relationship among p53 mutational status, MKK3/MKK6 and the downstream activated master kinase p38MAPK, dissecting a finely-tuned crosstalk, in a potentially cell-context dependent scenario that urges towards a deeper characterization of the different molecular players involved in this signaling cascade and their interactions.

The activation of OR51E1 causes growth suppression of human prostate cancer cells

The development of prostate cancer (PCa) is regulated by the androgen-dependent activity of the androgen receptor (AR). Androgen-deprivation therapy (ADT) is therefore the gold standard treatment to suppress malignant progression of PCa. Nevertheless, due to the development of castration resistance, recurrence of disease after initial response to ADT is a major obstacle to successful treatment. As G-protein coupled receptors play a fundamental role in PCa physiology, they might represent promising alternative or combinatorial targets for advanced diseases. Here, we verified gene expression of the olfactory receptors (ORs) OR51E1 [prostate-specific G-protein coupled receptor 2 (PSGR2)] and OR51E2 (PSGR) in human PCa tissue by RNA-Seq analysis and RT-PCR and elucidated the subcellular localization of both receptor proteins in human prostate tissue. The OR51E1 agonist nonanoic acid (NA) leads to the phosphorylation of various protein kinases and growth suppression of the PCa cell line LNCaP. Furthermore, treatment with NA causes reduction of androgen-mediated AR target gene expression. Interestingly, NA induces cellular senescence, which coincides with reduced E2F1 mRNA levels. In contrast, treatment with the structurally related compound 1-nonanol or the OR2AG1 agonist amyl butyrate, neither of which activates OR51E1, did not lead to reduced cell growth or an induction of cellular senescence. However, decanoic acid, another OR51E1 agonist, also induces cellular senescence. Thus, our results suggest the involvement of OR51E1 in growth processes of PCa cells and its impact on AR-mediated signaling. These findings provide novel evidences to support the functional importance of ORs in PCa pathogenesis.

An emerging role of astrocytes in vascular contributions to cognitive impairment and dementia

Vascular contributions to cognitive impairment and dementia (VCID) is understood to be the second most common cause of dementia after Alzheimer's disease, and is also a frequent comorbidity with Alzheimer's disease. While VCID is widely acknowledged as a key contributor to dementia, the mechanistic underpinnings of VCID remain poorly understood. In this review, we address the potential role of astrocytes in the pathophysiology of VCID. The vast majority of the blood vessels in the brain are surrounded by astrocytic end-feet. Given that astrocytes make up a significant proportion of the cells in the brain, and that astrocytes are usually passively connected to one another through gap junctions, we hypothesize that astrocytes are key mediators of cognitive impairment because of cerebrovascular disease. In this review, we discuss the existing body of literature regarding the role of astrocytes at the vasculature in the brain, and the known consequences of their dysfunction, as well as our hypotheses regarding the role astrocytes play in VCID. This article is part of the Special Issue "Vascular Dementia".

Tenascin-C induces migration and invasion through JNK/c-Jun signalling in pancreatic cancer

Tenascin-C (TNC), a large extracellular matrix glycoprotein, has been reported to be associated with metastasis and poor prognosis in pancreatic cancer. However, the effects and mechanisms of TNC in pancreatic cancer metastasis largely remain unclear. We performed Transwell assays to investigate the effects of TNC on Capan-2, AsPC-1 and PANC-1 cells. In addition, western blot and RT-qPCR assays were used to examine potential TNC metastasis-associated targets, such as JNK/c-Jun, Paxillin/FAK, E-cadherin, N-cadherin, Vimentin, and MMP9/2. Lastly, we utilized a variety of methods, such as immunofluorescence, gelatin zymography and immunoprecipitation, to determine the molecular mechanisms of TNC in pancreatic cancer cell motility. The present study showed that TNC induced migration and invasion in pancreatic cancer cells and regulated a number of metastasis-associated proteins, including the EMT markers, MMP9 and Paxillin. Moreover, our data showed that TNC induced pancreatic cancer cells to generate an EMT phenotype and acquire motility potential through the activation of JNK/c-Jun signalling. In addition, TNC increased the DNA binding activity of c-Jun to the MMP9 promoter, an action likely resulting in increased MMP9 expression and activity. TNC/JNK also markedly induced the phosphorylation of Paxillin on serine 178, which is critical for the association between FAK and Paxillin and promoted the formation of focal adhesions. TNC/JNK initiates cell migration and invasion of pancreatic cancer cells through the promotion of EMT, the transactivation of MMP9 and the phosphorylation of Paxillin on serine 178. TNC may be a potential therapeutic target for treating pancreatic cancer metastasis.

Taiwanin E inhibits cell migration in human LoVo colon cancer cells by suppressing MMP-2/9 expression via p38 MAPK pathway

Taiwanin E is a natural compound which is structurally analogous to estrogen II and is abundantly found in Taiwania cryptomerioides. It has been previously reported for its anticancer effects; however, the pharmaceutical effect of Taiwanin E on Human LoVo colon cancer cells is not clear. In this study, we investigated the effects of Taiwanin E on metastasis and the associated mechanism of action on Human LoVo colon cancer cells with respect to the modulations in their cell migration and signaling pathways associated with migration. The results showed that Taiwanin E inhibited cell migration ability correlated with reduced expression and activity of MMP-2 and MMP-9. In addition, Taiwanin E induced activation of p38 through phosphorylation. Inhibition of p38α/β significantly abolished the effect of Taiwanin E on cell migration and MMP-2/-9 activity. Our results conclude that Taiwanin E inhibited cell migration chiefly via p38α MAPK pathway and in a lesser extend via p38β MAPK. The results elucidate the potential of the phytoestrogen natural compound Taiwanin E as a cancer therapeutic agent in inhibiting the cell migration. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 2021-2031, 2017.

The K-Ras effector p38γ MAPK confers intrinsic resistance to tyrosine kinase inhibitors by stimulating EGFR transcription and EGFR dephosphorylation

Mutations in K-Ras and epidermal growth factor receptor (EGFR) are mutually exclusive, but it is not known how K-Ras activation inactivates EGFR, leading to resistance of cancer cells to anti-EGFR therapy. Here, we report that the K-Ras effector p38γ MAPK confers intrinsic resistance to small molecular tyrosine kinase inhibitors (TKIs) by concurrently stimulating EGFR gene transcription and protein dephosphorylation. We found that p38γ increases EGFR transcription by c-Jun-mediated promoter binding and stimulates EGFR dephosphorylation via activation of protein-tyrosine phosphatase H1 (PTPH1). Silencing the p38γ/c-Jun/PTPH1 signaling network increased sensitivities to TKIs in K-Ras mutant cells in which EGFR knockdown inhibited growth. Similar results were obtained with the p38γ-specific pharmacological inhibitor pirfenidone. These results indicate that in K-Ras mutant cancers, EGFR activity is regulated by the p38γ/c-Jun/PTPH1 signaling network, whose disruption may be a novel strategy to restore the sensitivity to TKIs.

CXC chemokine receptor 1 predicts postoperative prognosis and chemotherapeutic benefits for TNM II and III resectable gastric cancer patients

Backround: Abnormal expression of CXC chemokine receptor 1 (CXCR1) has shown the ability to promote tumor angiogensis, invasion and metastasis in several cancers. The purpose of our curret study is to discover the clinical prognostic significance of CXCR1 in resectable gastric cancer.

METHODS

330 gastric cancer patients who underwent R0 gastrectomy with standard D2 lymphadenectomy at Zhongshan Hospital, Fudan University between 2007 and 2008 were enrolled. CXCR1 expression was evaluated with use of immunohistochemical staining. The relation between CXCR1 expression and clinicopathological features and postoperative prognosis was respectively inspected.

RESULTS

In both discovery and validation data sets, CXCR1 high expression indicated poorer overall survival (OS) in TNM II and III patients. Furthermore, multivariate analysis identified CXCR1 expression and TNM stage as two independent prognostic factors for OS. Incorporating CXCR1 expression into current TNM staging system could generate a novel clinical predictive model for gastric cancer, showing better prognostic accuracy with respect to patients' OS. More importantly, TNM II patients with higher CXCR1 expression were shown to significantly benefit from postoperative 5-fluorouracil (5-FU) based adjuvant chemotherapy (ACT).

CONCLUSION

CXCR1 in gastric cancer was identified as an independent adverse prognostic factor. Combining CXCR1 expression with current TNM staging system could lead to better risk stratification and more accurate prognosis for gastric cancer patients. High expression of CXCR1 identified a subgroup of TNM stage II gastric cancer patients who appeared to benefit from 5-FU based ACT.

Time-course of glial changes in the hyperhomocysteinemia model of vascular cognitive impairment and dementia (VCID)

Vascular cognitive impairment and dementia (VCID) is the second leading cause of dementia behind Alzheimer's disease (AD) and is a frequent co-morbidity with AD. Despite its prevalence, little is known about the molecular mechanisms underlying the cognitive dysfunction resulting from cerebrovascular disease. Astrocytic end-feet almost completely surround intraparenchymal blood vessels in the brain and express a variety of channels and markers indicative of their specialized functions in the maintenance of ionic and osmotic homeostasis and gliovascular signaling. These functions are mediated by end-foot enrichment of the aquaporin 4 water channel (AQP4), the inward rectifying potassium channel Kir4.1 and the calcium-dependent potassium channel MaxiK. Using our hyperhomocysteinemia (HHcy) model of VCID we examined the time-course of astrocytic end-foot changes along with cognitive and neuroinflammatory outcomes. We found that there were significant astrocytic end-foot disruptions in the HHcy model. AQP4 becomes dislocalized from the end-feet, there is a loss of Kir4.1 and MaxiK protein expression, as well as a loss of the Dp71 protein known to anchor the Kir4.1, MaxiK and AQP4 channels to the end-foot membrane. Neuroinflammation occurs prior to the astrocytic changes, while cognitive impairment continues to decline with the exacerbation of the astrocytic changes. We have previously reported similar astrocytic changes in models of cerebral amyloid angiopathy (CAA) and therefore, we believe astrocytic end-foot disruption could represent a common cellular mechanism of VCID and may be a target for therapeutic development.

BRD4 Phosphorylation Regulates HPV E2-Mediated Viral Transcription, Origin Replication, and Cellular MMP-9 Expression

Post-translational modification can modulate protein conformation and alter binding partner recruitment within gene regulatory regions. Here, we report that bromodomain-containing protein 4 (BRD4), a transcription co-factor and chromatin regulator, uses a phosphorylation-induced switch mechanism to recruit E2 protein encoded by cancer-associated human papillomavirus (HPV) to viral early gene and cellular matrix metalloproteinase-9 (MMP-9) promoters. Enhanced MMP-9 expression, induced upon keratinocyte differentiation, occurs via BRD4-dependent recruitment of active AP-1 and NF-κB to their target sequences. This is triggered by replacement of AP-1 family members JunB and JunD by c-Jun and by re-localization of NF-κB from the cytoplasm to the nucleus. In addition, BRD4 phosphorylation is critical for E2- and origin-dependent HPV DNA replication. A class of phospho-BRD4-targeting compounds, distinct from the BET bromodomain inhibitors, effectively blocks BRD4 phosphorylation-specific functions in transcription and factor recruitment.

Naringin inhibits the invasion and migration of human glioblastoma cell via downregulation of MMP-2 and MMP-9 expression and inactivation of p38 signaling pathway

Gliomas are the most common and malignant primary brain tumors. They are associated with a poor prognosis despite the availability of multiple therapeutic options. Naringin, a common dietary flavonoid abundantly present in fruits and vegetables, is believed to possess strong anti-proliferative and anti-cancer properties. However, there are no reports describing its effects on the invasion and migration of glioblastoma cell lines. Our results showed that the treatment of U251 glioma cell lines with different concentrations of naringin inhibited the invasion and migration of these cells. In addition, we revealed a decrease in the levels of matrix metalloproteinases (MMP-2) and (MMP-9) expression as well as proteinase activity in U251 glioma cells. In contrast, the expression of tissue inhibitor of metalloproteinases (TIMP-1) and (TIMP-2) was increased. Furthermore, naringin treatment decreased significantly the phosphorylated level of p38. Combined treatment with a p38 inhibitor (SB203580) resulted in the synergistic reduction of MMP-2 and MMP-9 expressions correlated with an increase of TIMP-1 and TIMP-2 expressions and the anti-invasive properties. However, p38 chemical activator (anisomycin) could block these effects produced by naringin, suggesting a direct downregulation of the p38 signaling pathway. These data suggest that naringin may have therapeutic potential for controlling invasiveness of malignant gliomas by inhibiting of p38 signal transduction pathways.

Src Tyrosine Kinase Activation by 4-Hydroxynonenal Upregulates p38, ERK/AP-1 Signaling and COX-2 Expression in YPEN-1 Cells

4-Hydroxynonenal (4-HNE), a major end product of lipid peroxidation, is highly reactive and involved in various cellular processes, such as inflammatory signaling. However, to date, the mechanistic roles of 4-HNE in inflammatory signaling related to protein tyrosine kinases have not been elucidated. In the present study, we investigated the interaction between 4-HNE and Src (a non-receptor tyrosine kinase) for its involvement in the molecular modulation of the inflammatory signaling pathway utilizing the YPEN-1 cell system. Immunoprecipitation experiments showed that 4-HNE phosphorylates (activates) Src at Tyr416 via adduct formation. In addition, LC-MS/MS and a docking simulation model revealed an addiction site at the Cys248 residue of Src, resulting in the stimulation of downstream p38, ERK/AP-1 and cyclooxygenase-2 (COX-2) signaling in YPEN-1 cells. The role of 4-HNE-activated Src in downstream inflammatory signaling was further investigated using dasatinib (a Src inhibitor) and by siRNA knockdown of Src. p38 and ERK were directly regulated by Src, as revealed by immunoblotting of the phosphorylated forms of mitogen-activated protein kinases (MAPKs), which are key elements in the signaling transduction pathway initiated by Src. The study also shows that Src modulates the HNE-enhanced activation of AP-1 and the expression of COX-2 (a target gene of AP-1). Together, the results of this study show that 4-HNE stimulates Src tyrosine kinase in activation of the inflammation process.

LPS Induces Occludin Dysregulation in Cerebral Microvascular Endothelial Cells via MAPK Signaling and Augmenting MMP-2 Levels

Disrupted blood-brain barrier (BBB) integrity contributes to cerebral edema during central nervous system infection. The current study explored the mechanism of lipopolysaccharide- (LPS-) induced dysregulation of tight junction (TJ) proteins. Human cerebral microvascular endothelial cells (hCMEC/D3) were exposed to LPS, SB203580 (p38MAPK inhibitor), or SP600125 (JNK inhibitor), and cell vitality was determined by MTT assay. The proteins expressions of p38MAPK, JNK, and TJs (occludin and zonula occludens- (ZO-) 1) were determined by western blot. The mRNA levels of TJ components and MMP-2 were measured with quantitative real-time polymerase chain reaction (qRT-PCR), and MMP-2 protein levels were determined by enzyme-linked immunosorbent assay (ELISA). LPS, SB203580, and SP600125 under respective concentrations of 10, 7.69, or 0.22 µg/mL had no effects on cell vitality. Treatment with LPS decreased mRNA and protein levels of occludin and ZO-1 and enhanced p38MAPK and JNK phosphorylation and MMP-2 expression. These effects were attenuated by pretreatment with SB203580 or SP600125, but not in ZO-1 expression. Both doxycycline hyclate (a total MMP inhibitor) and SB-3CT (a specific MMP-2 inhibitor) partially attenuated the LPS-induced downregulation of occludin. These data suggest that MMP-2 overexpression and p38MAPK/JNK pathways are involved in the LPS-mediated alterations of occludin in hCMEC/D3; however, ZO-1 levels are not influenced by p38MAPK/JNK.

p38γ MAPK Is a Therapeutic Target for Triple-Negative Breast Cancer by Stimulation of Cancer Stem-Like Cell Expansion

Triple-negative breast cancer (TNBC) is highly progressive and lacks established therapeutic targets. p38γ mitogen-activated protein kinase (MAPK) (gene name: MAPK12) is overexpressed in TNBC but how overexpressed p38γ contributes to TNBC remains unknown. Here, we show that p38γ activation promotes TNBC development and progression by stimulating cancer stem-like cell (CSC) expansion and may serve as a novel therapeutic target. p38γ silencing in TNBC cells reduces mammosphere formation and decreases expression levels of CSC drivers including Nanog, Oct3/4, and Sox2. Moreover, p38γ MAPK-forced expression alone is sufficient to stimulate CSC expansion and to induce epithelial cell transformation in vitro and in vivo. Furthermore, p38γ depends on its activity to stimulate CSC expansion and breast cancer progression, indicating a therapeutic opportunity by application of its pharmacological inhibitor. Indeed, the non-toxic p38γ specific pharmacological inhibitor pirfenidone selectively inhibits TNBC growth in vitro and/or in vivo and significantly decreases the CSC population. Mechanistically, p38γ stimulates Nanog transcription through c-Jun/AP-1 via a multi-protein complex formation. These results together demonstrate that p38γ can drive TNBC development and progression and may be a novel therapeutic target for TNBC by stimulating CSC expansion. Inhibiting p38γ activity with pirfenidone may be a novel strategy for the treatment of TNBC.

p38γ MAPK is required for inflammation-associated colon tumorigenesis

Chronic inflammation has long been considered to causatively link to colon cancer development. However, signal transduction pathways involved remain largely unidentified. Here, we report that p38γ mitogen-activated protein kinase mediates inflammatory signaling to promote colon tumorigenesis. Inflammation activates p38γ in mouse colon tissues and intestinal epithelial cell-specific p38γ knockout (KO) attenuates colitis and inhibits pro-inflammatory cytokine expression. Significantly, p38γ KO inhibits tumorigenesis in a colitis-associated mouse model. The specific p38γ pharmacological inhibitor pirfenidone also suppresses pro-inflammatory cytokine expression and colon tumorigenesis. The tumor-promoting activity of epithelial p38γ was further demonstrated by xenograft studies. In addition, p38γ is required for β-catenin/Wnt activities and p38γ stimulates Wnt transcription by phosphorylating β-catenin at Ser605. These results show that p38γ activation links inflammation and colon tumorigenesis. Targeting p38γ may be a novel strategy for colon cancer prevention and treatment.

Identification of a ternary protein-complex as a therapeutic target for K-Ras-dependent colon cancer

A cancer phenotype is driven by several proteins and targeting a cluster of functionally interdependent molecules should be more effective for therapeutic intervention. This is specifically important for Ras-dependent cancer, as mutated (MT) Ras is non-druggable and targeting its interaction with effectors may be essential for therapeutic intervention. Here, we report that a protein-complex activated by the Ras effector p38γ MAPK is a novel therapeutic target for K-Ras-dependent colon cancer. Unbiased proteomic screening and immune-precipitation analyses identified p38γ interaction with heat shock protein 90 (Hsp90) and K-Ras in K-Ras MT, but not wild-type (WT), colon cancer cells, indicating a role of this complex in Ras-dependent growth. Further experiments showed that this complex requires p38γ and Hsp90 activity to maintain MT, but not WT, K-Ras protein expression. Additional studies demonstrated that this complex is activated by p38γ-induced Hsp90 phosphorylation at S595, which is important for MT K-Ras stability and for K-Ras dependent growth. Of most important, pharmacologically inhibition of Hsp90 or p38γ activity disrupts the complex, decreases K-Ras expression, and selectively inhibits the growth of K-Ras MT colon cancer in vitro and in vivo. These results demonstrated that the p38γ-activated ternary complex is a novel therapeutic target for K-Ras-dependent colon cancer.

PARVA promotes metastasis by modulating ILK signalling pathway in lung adenocarcinoma

α-parvin (PARVA) is known to be involved in the linkage of integrins, regulation of actin cytoskeleton dynamics and cell survival. However, the role that PARVA plays in cancer progression remains unclear. Here, using a lung cancer invasion cell line model and expression microarrays, we identify PARVA as a potential oncogene. The overexpression of PARVA increased cell invasion, colony-forming ability and endothelial cell tube formation. By contrast, knockdown of PARVA inhibited invasion and tube formation in vitro. Overexpression of PARVA also promoted tumorigenicity, angiogenesis and metastasis in in vivo mouse models. To explore the underlying mechanism, we compared the expression microarray profiles of PARVA-overexpressing cells with those of control cells to identify the PARVA-regulated signalling pathways. Pathway analysis showed that eight of the top 10 pathways are involved in invasion, angiogenesis and cell death. Next, to identify the direct downstream signalling pathway of PARVA, 371 significantly PARVA-altered genes were analysed further using a transcription factor target model. Seven of the top 10 PARVA-altered transcription factors shared a common upstream mediator, ILK. Lastly, we found that PARVA forms a complex with SGK1 and ILK to enhance the phosphorylation of ILK, which led to the phosphorylation of Akt and GSK3β. Notably, the inactivation of ILK reversed PARVA-induced invasion. Taken together, our findings imply that PARVA acts as an oncogene by activating ILK, and that this activation is followed by the activation of Akt and inhibition of GSK3β. To our knowledge, this is the first study to characterize the role of PARVA in lung cancer progression.

Characterization of c-Jun from orange-spotted grouper, Epinephelus coioides involved in SGIV infection

The nuclear phosphoprotein c-Jun is a member of the AP1 family of transcription activating complex, can be induced by various extracellular stimuli such as virus infection. In this study, the c-Jun gene (Ec-c-Jun) was cloned from orange-spotted grouper, Epinephelus coioides. The full-length Ec-c-Jun cDNA is composed of 2046 bp and encodes a polypeptide of 328 amino acids with 81% identity of zebrafish. Amino acid alignment analysis indicated that Ec-c-Jun contained three conserved domains including a transactivation domain (TAD), a DNA-binding domain (DBD) and leucine zipper domain (LZD). RT-PCR results showed that Ec-c-Jun transcript was most abundant in spleen, kidney, heart and gill. The expression of Ec-c-Jun was up-regulated after challenged with Singapore grouper iridovirus (SGIV). To investigate the roles of Ec-c-Jun during SGIV infection, we constructed its dominant-negative mutant (DN-Ec-c-Jun) by deleting the major TAD that lacks amino acids 3-122. Fluorescence microscopy observation revealed that Ec-c-Jun and DN-Ec-c-Jun were expressed predominantly in the nucleus in transfected cells. Interestingly, the green fluorescence of Ec-c-Jun was congregated and co-localized with virus assembly sites at the late stage of SGIV infection. However, in DN-Ec-c-Jun transfected cells, no virus assembly sites were observed, and the distribution of fluorescence remained unchanged. Moreover, overexpression of DN-Ec-c-Jun in vitro delayed the occurrence of CPE induced by SGIV infection and inhibited the virus gene transcription. In addition, ectopic expression of DN-Ec-c-Jun was able to inhibit SGIV induced c-Jun/AP1 promoter activity in GS cells. Thus, we proposed that c-Jun transcription factor was essential for SGIV replication in vitro. Our results will contribute to understanding the crucial roles of JNK signaling pathway in fish virus infection.

p38MAPK and MK2 pathways are important for the differentiation-dependent human papillomavirus life cycle

Amplification of human papillomaviruses (HPV) is dependent on the ATM DNA damage pathway. In cells with impaired p53 activity, DNA damage repair requires the activation of p38MAPK along with MAPKAP kinase 2 (MK2). In HPV-positive cells, phosphorylation of p38 and MK2 proteins was induced along with relocalization to the cytoplasm. Treatment with MK2 or p38 inhibitors blocked HPV genome amplification, identifying the p38/MK2 pathway as a key regulator of the HPV life cycle.

Imatinib preserves blood-brain barrier integrity following experimental subarachnoid hemorrhage in rats

Blood-brain barrier (BBB) disruption and consequent edema formation contribute to the development of early brain injury following subarachnoid hemorrhage (SAH). Various cerebrovascular insults result in increased platelet-derived growth factor receptor (PDGFR)-α stimulation, which has been linked to BBB breakdown and edema formation. This study examines whether imatinib, a PDGFR inhibitor, can preserve BBB integrity in a rat endovascular perforation SAH model. Imatinib (40 or 120 mg/kg) or a vehicle was administered intraperitoneally at 1 hr after SAH induction. BBB leakage, brain edema, and neurological deficits were evaluated. Total and phosphorylated protein expressions of PDGFR-α, c-Src, c-Jun N-terminal kinase (JNK), and c-Jun were measured, and enzymatic activities of matrix metalloproteinase (MMP)-2 and MMP-9 were determined in the injured brain. Imatinib treatment significantly ameliorated BBB leakage and edema formation 24 hr after SAH, which was paralleled by improved neurological functions. Decreased brain expressions of phosphorylated PDGFR-α, c-Src, JNK, and c-Jun as well as reduced MMP-9 activities were found in treated animals. PDGFR-α inhibition preserved BBB integrity following experimental SAH; however, the protective mechanisms remain to be elucidated. Targeting PDGFR-α signaling might be advantageous to ameliorate early brain injury following SAH.

Kynurenic acid inhibits colon cancer proliferation in vitro: effects on signaling pathways

Kynurenic acid (KYNA), a tryptophan metabolite, inhibits proliferation of several cancer cell lines including colon cancer, renal cancer and glioblastoma cells. Previous studies reported that inhibitory properties of KYNA may be related to interactions of KYNA with cell cycle regulators and signaling proteins. However, the exact molecular interaction of KYNA with signaling pathways in colon cancer cells has not been studied to date. The molecular mechanism of KYNA activity towards colon cancer cells may be of great importance taking into consideration that KYNA is present in several tissues and physiological fluids, including gastrointestinal tract, and it is also present in various products of human diet. In this study, the inhibitory effect of KYNA on activation of phosphoinositide 3-kinase/Akt (PI3K/Akt) and mitogen-activated protein kinase (MAPK) signaling pathways in colon adenocarcinoma HT-29 cells was revealed. KYNA decreased phosphorylation of Akt, ERK 1/2 and p38 kinases in HT-29 cells. Interestingly, the study revealed also unexpected effect of KYNA on Wnt pathway in HT-29 cells. KYNA in millimolar concentrations increased protein expression of β-catenin. However, the nuclear translocation of β-catenin in HT-29 cells exposed to KYNA was not observed. Moreover, KYNA 1 mM increased antiproliferative properties of inhibitors of signaling pathways: wortmannin, PD98059, SB202190 and IWR-1. Taking into consideration these results, KYNA may be seen as a potential chemopreventive agent in colon cancer or supportive agent in standard cancer chemotherapy. However, the interactions between KYNA, Wnt signaling pathway and β-catenin need further studies to exclude potential effect of KYNA on colon carcinogenesis.

Association of CXCR1 and 2 expressions with gastric cancer metastasis in ex vivo and tumor cell invasion in vitro

BACKGROUND

CXCR1 and CXCR2, cell surface receptors of interleukin-8, regulate cell migration and alteration of their expression has been associated with poor prognosis of various cancers. The aim of this study was to detect their expression in gastric cancer to identify associations with another cell adhesion molecule, matrix metalloproteinase-9 (MMP9), and with clinicopathological data ex vivo, and then explore their potential role in gastric cancer cells in vitro.

MATERIALS AND METHODS

A total of 172 cases of gastric cancer tissue specimens were collected for immunohistochemical analysis of CXCR1, CXCR2, and MMP9 expression. Expression of CXCR1 and CXCR2 proteins was knocked in or down using their cDNA and shRNA, respectively, in gastric cancer cell lines to assess the changed cell phenotypes and gene expression.

RESULTS

CXCR1, CXCR2, and MMP9 were expressed in 61.0%, 77.9%, and 75.6% of gastric cancer tissues, respectively. Moreover, CXCR1 and CXCR2 expression was associated with tumor differentiations, advanced clinical stages, lymph node, and distant metastasis of gastric cancer. Similarly, MMP9 expression was associated with CXCR1 and CXCR2. Expression of these three proteins was interrelated. In vitro study showed that levels of CXCR1 and CXCR2 proteins were associated with the capacity of gastric cancer cell migration, while knockdown of their expression inhibited gastric cancer cell migration and invasion abilities in vitro. In contrast, overexpression of CXCR1 and CXCR2 proteins promoted tumor cell migration and invasion. At the gene levels, knockdown of CXCR1 or CXCR2 expression suppressed expression of Ets-1, SRC-1, and JNK proteins and phosphorylated c-Jun and Erk1/2. Conversely, upregulation of CXCR1 or CXCR2 promoted expression of Ets-1, SRC-1, JNK, and c-Jun proteins and phosphorylated JNK, c-Jun and Erk1/2.

CONCLUSIONS

These findings suggest that CXCR1 and CXCR2 play an important role in gastric cancer progression. Further study will be performed to investigate whether target of their expression can be used as a novel strategy in clinical control of gastric cancer metastasis.

The role of matrix metalloproteinases in colorectal cancer

In the United States, colorectal cancer (CRC) is the third leading cause of cancer mortality, with limited treatment options for those with advanced disease. Matrix metalloproteinases (MMPs) are important for maintaining extracellular homeostasis but also play a prominent role in cancer cell invasion and dissemination. Expression levels of MMP-1, -2, -7, -9 and -13 correlate with worse outcomes; MMP-12 expression appears to be protective. Hence, MMPs are attractive therapeutic targets. Previous clinical trials using broad-spectrum MMP inhibitors were disappointing because of off-target toxicity and lack of efficacy. Now, the availability of safer, more selective inhibitors has renewed interest in therapeutic targeting of MMPs.