Predicting lymphoma in Sjögren's syndrome and the pathogenetic role of parotid microenvironment through precise parotid swelling recording.

OBJECTIVE: Parotid swelling (PSW) is a major predictor of non-Hodgkin's lymphoma (NHL) in primary SS (pSS). However, since detailed information on the time of onset and duration of PSW is scarce, this was investigated to verify whether it may lead to further improved prediction. NHL localization was concomitantly studied to evaluate the role of the parotid gland microenvironment in pSS-related lymphomagenesis. METHODS: A multicentre study was conducted among patients with pSS who developed B cell NHL during follow-up and matched controls that did not develop NHL. The study focused on the history of salivary gland and lachrymal gland swelling, evaluated in detail at different times and for different durations, and on the localization of NHL at onset. RESULTS: PSW was significantly more frequent among the cases: at the time of first referred pSS symptoms before diagnosis, at diagnosis and from pSS diagnosis to NHL. The duration of PSW was evaluated starting from pSS diagnosis, and the NHL risk increased from PSW of 2-12 months to >12 months. NHL was prevalently localized in the parotid glands of the cases. CONCLUSION: A more precise clinical recording of PSW can improve lymphoma prediction in pSS. PSW as a very early symptom is a predictor, and a longer duration of PSW is associated with a higher risk of NHL. Since lymphoma usually localizes in the parotid glands, and not in the other salivary or lachrymal glands, the parotid microenvironment appears to be involved in the whole history of pSS and related lymphomagenesis.

Nuts and bolts of salivary gland pathology in primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is a chronic, systemic, inflammatory autoimmune disease characterised by lymphocyte proliferation and progressive damage to exocrine glands. Salivary gland histopathology based on salivary gland biopsy is relevant for the diagnosis of pSS and therefore broadly applied in clinical practice. Tissue can be obtained from labial salivary glands (LSG) biopsy or from major salivary glands (MSG) biopsy, namely the parotid; in this latter scenario, the procedure can be either an open surgical biopsy or a US guided core needle biopsy.In this review we will: i) present the histopathological findings that may be encountered by pathologists on biopsies from pSS patients; ii) discuss the advantages and disadvantages of the surgical and/or imaging guided procedures to obtain tissues from LSG or MSG; iii) describe the histopathological features of lymphoma of MSG in pSS patients.

Arachidonic acid induces brain endothelial cell apoptosis via p38-MAPK and intracellular calcium signaling.

Arachidonic acid (AA), a bioactive fatty acid whose levels increase during neuroinflammation, contributes to cerebral vascular damage and dysfunction. However, the mode of injury and underlying signaling mechanisms remain unknown. Challenge of primary human brain endothelial cells (HBECs) with AA activated a stress response resulting in caspase-3 activation, poly(ADP-ribose) polymerase cleavage, and disruption of monolayer integrity. AA also induced loss of mitochondrial membrane potential and cytochrome c release consistent with activation of intrinsic apoptosis. HBEC stimulation with AA resulted in sustained p38-MAPK activation and subsequent phosphorylation of mitogen-activated protein kinase activated protein-2 (MAPKAP-2) kinase and heat shock protein-27 (Hsp27). Conversely, other unsaturated and saturated fatty acids had no effect. Pharmacological and RNA interference-mediated p38α or p38ß suppression abrogated AA signaling to caspase-3 and Hsp27, suggesting involvement of both p38 isoforms in AA-induced HBEC apoptosis. Hsp27 silencing also blocked caspase-3 activation. AA stimulated intracellular calcium release, which was attenuated by inositol 1,4,5-trisphosphate (IP3) receptor antagonists. Blockade of intracellular calcium release decreased caspase-3 activation, but had no effect on AA-induced p38-MAPK activation. However, inhibition of p38-MAPK or blockade of intracellular calcium mobilization abrogated AA-induced cytochrome c release. AA-induced caspase-3 activation was abrogated by pharmacological inhibition of lipooxygenases. These findings support a previously unrecognized signaling cooperation between p38-MAPK/MAPKAP-2/Hsp27 and intracellular calcium release in AA-induced HBEC apoptosis and suggest its relevance to neurological disorders associated with vascular inflammation.

Clinical outcomes of ramucirumab plus docetaxel in the treatment of patients with non-small cell lung cancer after immunotherapy: a systematic literature review.

Introduction: In the REVEL trial, ramucirumab plus docetaxel demonstrated significant improvements in overall survival (OS), progression-free survival (PFS), and overall response rate (ORR) compared with placebo plus docetaxel for treatment of metastatic non-small cell lung cancer (NSCLC) that progressed during or after platinum-based chemotherapy. Since the approval of ramucirumab plus docetaxel, immune checkpoint inhibitors (ICIs), either as single agents or in combination with chemotherapy, have become the standard of care for first-line treatment of patients with advanced NSCLC. However, efficacy and safety data for ramucirumab plus docetaxel after prior ICI treatment from randomized controlled clinical studies are lacking. Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic literature review was performed. Electronic databases and select international oncology conference proceedings were searched. Studies published between 01 January 2014 and 01 July 2022, which evaluated 2 efficacy outcomes (and included at least 1 time-to-event endpoint) or safety outcomes of ramucirumab plus docetaxel in NSCLC that progressed after prior ICI treatment, were identified. Twelve studies were included in the analysis. Two treatment groups were selected: ramucirumab plus docetaxel after prior ICI ± chemotherapy (RAM + DTX ICI pre-treated) and ramucirumab plus docetaxel after prior chemotherapy only (RAM + DTX ICI naïve). OS, PFS, ORR, disease control rate (DCR), and safety data were extracted and descriptively summarized across both treatment groups. Results: The pooled weighted median PFS and median OS were 5.7 months (95% confidence interval [CI]: 3.9-6.8) and 11.2 months (95% CI: 7.5-17.5), respectively, in the RAM + DTX ICI pre-treated group and 3.8 months (95% CI: 2.3-4.1) and 13.5 months (95% CI: 8-24.0), respectively, in the RAM + DTX ICI naïve group. The ORR and DCR ranged from 20.9% to 60.0% and from 62.4% to 90.0%, respectively, in the RAM + DTX ICI pre-treated group and from 17.7% to 20.0% and from 57.1% to 75.0%, respectively, in the RAM + DTX ICI naïve group. The safety profile across studies was consistent between both treatment groups, and no new safety signals were reported. Conclusions: Cumulatively, these results support the combination of ramucirumab plus docetaxel as an effective and safe subsequent therapy for the treatment of patients with metastatic NSCLC with disease progression irrespective of previous ICI treatment.

Overall Survival and Safety With Pemetrexed/Platinum ± Anti-VEGF Followed by Pemetrexed ± Anti-VEGF Maintenance in Advanced Nonsquamous Non-Small-Cell Lung Cancer: A Pooled Analysis of 4 Randomized Studies.

BACKGROUND: Before immune checkpoint blockade therapy, chemotherapy with pemetrexed maintenance was the standard of care for patients with advanced nonsquamous non-small-cell lung cancer (NSQ-NSCLC) and remains such where immunotherapy is not applicable. This pooled analysis aimed to characterize overall survival (OS) and safety of pemetrexed ± anti-VEGF maintenance, by treatment duration. PATIENTS AND METHODS: Data from 4 randomized clinical trials (PARAMOUNT, PRONOUNCE, PointBreak, JVBL) of patients with NSQ-NSCLC receiving pemetrexed ± anti-VEGF maintenance therapy were pooled as 2 groups (Group A: pemetrexed-only maintenance, n = 486; and Group B: pemetrexed + anti-VEGF maintenance, n = 329). OS and treatment-emergent adverse events (TEAEs) were analyzed in both groups by treatment duration. RESULTS: Baseline characteristics were well balanced between both groups. Median OS did not significantly differ between Group A (16.1 months) and Group B (18.4 months; hazard ratio: 1.17, P= .1417). A correlation between median OS and treatment duration was numerically stronger in Group A (r = 0.72) versus B (r = 0.62). Across treatment groups, TEAEs were largely grade 1 to 2 and, with few exceptions, did not increase with increased treatment duration. CONCLUSION: There was no significant OS difference between pemetrexed-only and pemetrexed ± anti-VEGF maintenance in patients with NSQ-NSCLC. Patients receiving pemetrexed + anti-VEGF experienced a slightly less favorable safety profile with more reported TEAEs compared to pemetrexed monotherapy. Pemetrexed ± anti-VEGF maintenance therapy may be considered in NSQ-NSCLC, based on an individualized patient approach, particularly where immunotherapy is not clinically indicated.

Pemetrexed and Platinum Plus Pembrolizumab in Patients With Metastatic Nonsquamous NSCLC by Tumor Burden at Baseline: A Post Hoc Efficacy Analysis of KEYNOTE-189.

Introduction: The aim of this study was to evaluate the efficacy of pemetrexed and platinum plus pembrolizumab by baseline tumor burden. Methods: A total of 616 patients in the intention-to-treat population of the KEYNOTE-189 study were included in this analysis. Baseline tumor burden subgroups were identified on the basis of extent of distant metastasis (M1a versus M1b), median number (≤3 versus >3) of organ systems with lesions, or symptom severity score of patient-reported lung cancer-associated symptoms (≤median versus >median). Overall survival (OS), progression-free survival (PFS), and PFS-2 were evaluated by Kaplan-Meier and univariate Cox methods. Objective response rate was analyzed using logistic regression models, and duration of response was analyzed descriptively. Efficacy outcomes were also analyzed according to the programmed death-ligand 1 expression levels. Results: OS and PFS were significantly improved with pemetrexed and platinum plus pembrolizumab in all baseline tumor burden subgroups (M1a stage: OS hazard ratio [HR] = 0.54, p = 0.0037; PFS HR = 0.48, p = 0.0001; M1b stage: OS HR = 0.58, p ≤ 0.0001; PFS HR = 0.51, p ≤ 0.0001; number of organ systems with lesion ≤ 3: OS HR = 0.49, p ≤ 0.0001 PFS HR = 0.41, p ≤ 0.0001; >3: OS HR = 0.67, p = 0.0068; PFS HR = 0.59, p = 0.0001; symptom severity score ≤ median: HR = 0.51, p ≤ 0.0001; PFS HR 0.49, p ≤ 0.0001; > median: OS HR = 0.60, p = 0.0003; PFS HR = 0.48, p ≤ 0.0001). PFS2 and objective response rate were also improved with pemetrexed and platinum plus pembrolizumab in all baseline tumor burden subgroups. Efficacy outcomes were generally consistent regardless of programmed death-ligand 1 expression levels. Conclusions: Pemetrexed and platinum plus pembrolizumab were found to have relevant efficacy regardless of the extent of baseline tumor burden and the variables used to define it. These results further support pemetrexed and platinum plus pembrolizumab as the standard of care in the first-line treatment of metastatic nonsquamous NSCLC.

TP53 Co-Mutation Status Association with Clinical Outcomes in Patients with EGFR-Mutant Non-Small Cell Lung Cancer.

TP53 co-mutations have shown association with poor prognosis in various solid tumors. For EGFR-mutated advanced non-small cell lung cancer (aNSCLC), conflicting results exist regarding its impact on survival. Clinical outcomes and genomic data were obtained retrospectively from the real-world (rw) de-identified clinicogenomic database. Patients who initiated therapy for EGFR-mutated aNSCLC between January 2014 and December 2020 were identified. Clinical outcomes were evaluated by TP53-mutational status. In 356 eligible EGFR-mutated aNSCLC patients (median age 68 years), 210 (59.0%) had TP53 co-mutation and 146 (41.0%) had TP53 wild-type tumor. Unadjusted analysis showed significantly shorter survival in patients with TP53 co-mutation versus TP53 wild-type (rw progression-free survival [rwPFS]: HR = 1.4, 95% CI 1.1-1.9, p = 0.0196; overall survival [OS]: HR = 1.6, 95% CI 1.1-2.2, p = 0.0088). Multivariable analysis confirmed independent association between TP53 co-mutation and worse rwPFS (HR = 1.4, 95% CI 1.0-0.9, p = 0.0280) and OS (HR = 1.4, 95% CI 1.0-2.0, p = 0.0345). Directionally consistent findings were observed for response rates, and subgroups by EGFR-activating mutation and first-line (1 L) therapy, with more pronounced negative effect in 1 L EGFR-TKI subgroup. TP53 co-mutations negatively affected survival in patients with EGFR-mutated aNSCLC receiving standard 1 L therapy in real-world practice.

Shared Pathogenetic Features Between Common Variable Immunodeficiency and Sjögren's Syndrome: Clues for a Personalized Medicine.

Common variable immunodeficiency disorders (CVID) are a group of rare diseases of the immune system and the most common symptomatic primary antibody deficiency in adults. The "variable" aspect of CVID refers to the approximately half of the patients who develop non-infective complications, mainly autoimmune features, in particular organ specific autoimmune diseases including thyroiditis, and cytopenias. Among these associated conditions, the incidence of lymphoma, including mucosal associated lymphoid tissue (MALT) type, is increased. Although these associated autoimmune disorders in CVID are generally attributed to Systemic Lupus Erythematosus (SLE), we propose that Sjogren's syndrome (SS) is perhaps a better candidate for the associated disease. SS is an autoimmune disorder characterized by the lymphocytic infiltrates of lacrimal and salivary glands, leading to dryness of the eyes and mouth. Thus, it is a lymphocyte aggressive disorder, in contrast to SLE where pathology is generally attributed to auto-antibody and complement activation. Although systemic lupus erythematosus (SLE) shares these features with SS, a much higher frequency of MALT lymphoma distinguishes SS from SLE. Also, the higher frequency of germ line encoded paraproteins such as the monoclonal rheumatoid factor found in SS patients would be more consistent with the failure of B-cell VDJ switching found in CVID; and in contrast to the hypermutation that characterizes SLE autoantibodies. Thus, we suggest that SS may fit as a better "autoimmune" association with CVID. Examining the common underlying biologic mechanisms that promote lymphoid infiltration by dysregulated lymphocytes and lymphoma in CVID may provide new avenues for treatment in both the diseases. Since the diagnosis of SLE or rheumatoid arthritis is usually based on specific autoantibodies, the associated autoimmune features of CVID patients may not be recognized in the absence of autoantibodies.

Safety of pemetrexed plus platinum in combination with pembrolizumab for metastatic nonsquamous non-small cell lung cancer: A post hoc analysis of KEYNOTE-189.

OBJECTIVES: This post hoc analysis assessed the safety of pemetrexed and platinum in combination with pembrolizumab, including time-to-onset and time-to-resolution of all-cause any-grade and grade ≥3 adverse events (AEs) and renal AEs. MATERIALS AND METHODS: Patient-level data from KEYNOTE-189 were analyzed in the all-subjects-as-treated population (pembrolizumab arm, n = 405; placebo arm, n = 202), and among patients who received ≥5 cycles of pemetrexed (pemetrexed/pembrolizumab/platinum arm, n = 310; pemetrexed/placebo/platinum arm, n = 135). All-cause AEs were selected based on ≥2 % incidence from previously reported KEYNOTE-189 data and included neutropenia, febrile neutropenia, anemia, thrombocytopenia, asthenia, fatigue, dyspnea, diarrhea, nausea, vomiting, pneumonitis, and renal events. Descriptive statistics summarized all-cause AEs. Medians and interquartile ranges were used to examine time-to-onset and time-to-resolution. The data cutoff was November 8, 2017. RESULTS: In both treatment arms, most non-hematologic (nausea, vomiting, diarrhea, and asthenia), and hematologic (febrile neutropenia, thrombocytopenia, and neutropenia) grade ≥3 AEs with ≥2 % incidence had a median time-to-onset within the first 4 cycles, and a median time-to-resolution of within 2 weeks from onset. A small number of AEs had longer median time-to-onset (pneumonitis and fatigue) and median time-to-resolution (pneumonitis, fatigue, acute kidney injury, and anemia). Among patients who received ≥5 cycles of pemetrexed, the incidence of any-grade renal toxicity in the pemetrexed/pembrolizumab/platinum arm was 2.3 % in Cycles 1-4, 4.8 % in Cycles 5-8, 2.6 % in Cycles 9-12, and 2.5 % in Cycles ≥13; and, in the pemetrexed/placebo/platinum arm, 0.7 % in Cycles 1-4, 1.5 % in Cycles 5-8, 1.3 % in Cycles 9-12, and 2.0 % in Cycles ≥13. CONCLUSION: Pemetrexed/pembrolizumab/platinum has manageable toxicity with longer duration of treatment. While the incidence of renal toxicity was slightly higher in the pembrolizumab combination as compared to pemetrexed, the incidence did not increase in later treatment cycles. These results support the safe use of the KEYNOTE-189 regimen in clinical practice. CLINICAL TRIAL REGISTRATION NUMBER: NCT02578680 (clinicaltrials.gov).

Prostaglandin E2 activates cAMP response element-binding protein in glioma cells via a signaling pathway involving PKA-dependent inhibition of ERK.

Prostaglandin E(2) (PGE(2)) plays a critical role in influencing the biological behavior of tumor cells. We previously demonstrated that PGE(2) stimulates human glioma cell growth via activation of protein kinase A (PKA) type II. This study was undertaken to further elucidate the intracellular pathways activated by PGE(2) downstream to PKA. Stimulation of U87-MG glioma cells with PGE(2) increased phosphorylation of the cyclic-AMP response element (CRE) binding protein CREB at Ser-133 and CREB-driven transcription in a dose- and time-dependent manner. Expression of dominant CREB constructs that interfere with CREB phosphorylation at Ser-133 or with its binding to the CRE site markedly decreased PGE(2)-induced CREB activation. Inhibition of PKA by H-89 or expression of a dominant negative PKA construct attenuated PGE(2)-induced CREB activation. Moreover, inhibition of PKA type II decreased PGE(2)-induced CREB-dependent transcription by 45% compared to vehicle-treated cells. To investigate the involvement of additional signaling pathways, U87-MG cells were pretreated with wortmannin or LY294002 to inhibit the PI3-kinase/AKT pathway. Both inhibitors had no effect on PGE(2)-induced CREB phosphorylation and transcriptional activity, suggesting that PGE(2) activates CREB in a PI3-kinase/AKT independent manner. Challenge of U87-MG cells with PGE(2), at concentrations that induced maximal CREB activation, or with forskolin inhibited extracellular signal-regulated kinase (ERK) phosphorylation. Pretreatment of U87-MG cells with the ERK inhibitor PD98059, accentuated ERK inhibition and increased CREB phosphorylation at Ser-133 and CREB-driven transcription stimulated by PGE(2), suggesting that inhibition of ERK contributes to PGE(2)-induced CREB activation. Inhibition of ERK by PGE(2) or by forskolin was rescued by treatment of cells with H-89 or by the dominant negative PKA construct. Moreover, PGE(2) or forskolin inhibited phosphorylation of Raf-1 phosphorylation at Ser-338. Challenge of U87-MG cells with 11-deoxy-PGE(1) increased CREB-driven transcription and stimulated cell growth, while other PGE(2) analogues had no effect. Together our results reveal a novel signaling pathway whereby PGE(2) signals through PKA to inhibit ERK and increase CREB transcriptional activity.

Microsomal prostaglandin E synthase-1 regulates human glioma cell growth via prostaglandin E(2)-dependent activation of type II protein kinase A.

Dysregulation of enzymes involved in prostaglandin biosynthesis plays a critical role in influencing the biological behavior and clinical outcome of several tumors. In human gliomas, overexpression of cyclooxygenase-2 has been linked to increased aggressiveness and poor prognosis. In contrast, the role of prostaglandin E synthase in influencing the biological behavior of human gliomas has not been established. We report that constitutive expression of the microsomal prostaglandin E synthase-1 (mPGES-1) is associated with increased prostaglandin E(2) (PGE(2)) production and stimulation of growth in the human astroglioma cell line U87-MG compared with human primary astrocytes. Consistently, pharmacologic and genetic inhibition of mPGES-1 activity and expression blocked the release of PGE(2) from U87-MG cells and decreased their proliferation. Conversely, exogenous PGE(2) partially overcame the antiproliferative effects of mPGES-1 inhibition and stimulated U87-MG cell proliferation in the absence of mPGES-1 inhibitors. The EP2/EP4 subtype PGE(2) receptors, which are linked to stimulation of adenylate cyclase, were expressed in U87-MG cells to a greater extent than in human astrocytes. PGE(2) increased cyclic AMP levels and stimulated protein kinase A (PKA) activity in U87-MG cells. Treatment with a selective type II PKA inhibitor decreased PGE(2)-induced U87-MG cell proliferation, whereas a selective type I PKA inhibitor had no effect. Taken together, these results are consistent with the hypothesis that mPGES-1 plays a critical role in promoting astroglioma cell growth via PGE(2)-dependent activation of type II PKA.

Potential involvement of the cyclooxygenase-2 pathway in the regulation of tumor-associated angiogenesis and growth in pancreatic cancer.

Angiogenesis plays a crucial role in tumor development and growth. The present investigation was undertaken to test the potential involvement of the cyclooxygenase-2 (COX-2) pathway in the regulation of angiogenesis and growth in pancreatic cancer. We compared the angiogenic characteristics of a COX-2-positive human pancreatic tumor cell line, BxPC-3, with those of a COX-2-negative pancreatic tumor cell line, AsPC-1. Cultured BxPC-3 cells promoted a marked increase of endothelial cell migration in comparison with migration that occurred in the absence of cancer cells. Furthermore, BxPC-3 cell culture supernatants induced endothelial cell capillary morphogenesis in vitro and neovascularization in vivo. In contrast, cultured AsPC-1 cells elicited a modest effect on endothelial cell migration and neovascularization in vivo. Pretreatment of BxPC-3 cells with the selective COX-2 inhibitor NS-398 (50 micro M) dramatically decreased angiogenic responses of endothelial cells. NS-398 (25-100 micro M) caused inhibition of BxPC-3 cell proliferation but had no effect on AsPC-1 cell growth. SC-560, a selective COX-1 inhibitor, had no effect on growth of either cell lines. These results suggest an involvement of COX-2 in the control of tumor-dependent angiogenesis and growth in certain pancreatic cancers and provide the rational for inhibition of the COX pathway as an effective therapeutic approach for pancreatic tumors.

Specificity of arachidonic acid-induced inhibition of growth and activation of c-jun kinases and p38 mitogen-activated protein kinase in hematopoietic cells.

We demonstrated that arachidonic acid inhibits growth and induces apoptosis in the bcr-abl transformed leukemia cell line, H7.bcr-abl A54 and in human chronic myeloid leukemia hematopoietic cells. This investigation was undertaken to determine the cell-type specificity of this response. We compared the effect of arachidonic acid on H7.bcr-abl A54 cells to Jurkat (human acute T-cell leukemia), U937 (human histiocytic lymphoma) and RPMI 7666 (human normal B-lymphoblasts) cells. Arachidonic acid (100 microM, 72 h) inhibited growth of H7.bcr-abl A54, Jurkat and U937 cells by 82.2, 67.5 and 20%, respectively, but had no effect on RPMI 7666 cells. These effects were investigated in relationship to the activation of p38 mitogen activated protein kinase (p38 MAPK) and c-jun amino-terminal kinase (JNK) by arachidonic acid in these cell lines. Results from these studies suggest that signaling and proliferative responses to arachidonic acid are cell-type specific. Leukemia cells appear to be more sensitive to the antiproliferative effect of arachidonic acid than normal cells.

Cyclooxygenase-2 in oncogenesis.

Compelling experimental and clinical evidence supports the notion that cyclooxygenase-2, the inducible isoform of cyclooxygenase, plays a crucial role in oncogenesis. Clinical and epidemiological data indicate that aberrant regulation of cyclooxygenase-2 in certain solid tumors and hematological malignancies is associated with adverse clinical outcome. Moreover, findings extrapolated from experimental studies in cultured tumor cells and animal tumor models indicate that cyclooxygenase-2 critically influences all stages of tumor development from tumor initiation to tumor progression. Cyclooxygenase-2 elicits cell-autonomous effects on tumor cells resulting in stimulation of growth, increased cell survival, enhanced tumor cell invasiveness, stimulation of neovascularization, and tumor evasion from the host immune system. Additionally, the oncogenic effects of cyclooxygenase-2 stem from its unique ability to impact tumor cell surroundings and create a proinflammatory environment conducive for tumor development, growth and progression. The initial enthusiasm generated by the availability of cyclooxygenase-2 selective inhibitors for cancer prevention and therapy has been lessened by the severe cardiovascular adverse side effects associated with their long-term use, as well as by the mixed results of recent clinical trials evaluating the efficacy of cyclooxygenase-2 inhibitors in adjuvant chemotherapy. Therefore, our ability to efficiently target the oncogenic effects of cyclooxygenase-2 for therapeutic and preventive purposes strictly depends on a better understanding of the spatial and temporal aspects of its activation in tumor cells along with a clearer elucidation of the signaling networks whereby cyclooxygenase-2 affects tumor cells and their interactions with the tumor microenvironment. This knowledge has the potential of leading to the identification of novel cyclooxygenase-2-dependent molecular and signaling networks that can be exploited to improve cancer prevention and therapy.

Brain endothelial cell death: modes, signaling pathways, and relevance to neural development, homeostasis, and disease.

Emerging evidence indicates that brain microvascular endothelial cells play a critical role in brain development, maturation, and homeostasis. Acute or chronic insults, including oxidative stress, oxygen-glucose deprivation, trauma, infections, inflammatory cytokines, DNA damaging agents, beta-amyloid deposition, and endoplasmic reticulum stress induce brain endothelial cell dysfunction and damage, which can result in cell death. The homeostatic balance between endothelial cell survival and endothelial cell death is critical for brain development, remodeling, and repair. On the other hand, dysregulation of brain endothelial cell death exacerbates, or even initiates, several inflammatory, ischemic, and degenerative disorders of the central nervous system. In here, the morphological, biochemical, and functional characteristics of the brain endothelium and its contribution to brain homeostasis will be reviewed. Recent insights into modalities and regulatory pathways involved in brain endothelial cell death will be described. The effects of regulated and dysregulated endothelial cell death leading to angiogenesis will be outlined. The relevance of brain endothelial cell dysfunction and death to disease processes will be discussed with special reference to recent findings that could help translate current knowledge on brain endothelial cell apoptosis into new therapeutic strategies for the treatment of certain neurological disorders.

c-jun amino-terminal kinase and mitogen activated protein kinase 1/2 mediate hepatocyte growth factor-induced migration of brain endothelial cells.

Hepatocyte growth factor (HGF) influences several components of the angiogenic response, including endothelial cell migration. While recent studies indicate a crucial role of HGF in brain angiogenesis, the signaling pathways that regulate brain endothelial cell migration by HGF remain uncharacterized. Herein, we report that HGF stimulated human brain microvascular endothelial cell (HBMEC) migration in a dose- and time-dependent manner. Challenge of HBMECs with HGF activated the c-jun amino-terminal kinase (JNK), increased phosphorylation of the proline-rich tyrosine kinase 2 (Pyk-2) at Tyr(402) and activated c-Src. Inhibition of JNK by SP600125 or expression of a dominant negative JNK1 construct abrogated the migratory response of HBMECs to HGF. Treatment of HBMECs with the Src inhibitor PP2 markedly decreased HGF-stimulated JNK activation and migration to HGF. Moreover, expression of a mutant Pyk-2 construct prevented HGF-induced Pyk-2 phosphorylation at Tyr(402) and stimulation of HBMEC migration. Next, we examined activation of the extracellular signal regulated kinase (ERK) pathway. Stimulation of HBMECs by HGF led to rapid activation of ERK1/2, phosphorylation of Raf-1 at Ser(338) and Tyr(340/341) and MEK1/2 at Ser(222). Moreover, inhibition of ERK activation by UO126 and PD98059 markedly decreased HGF-stimulated HBMEC migration. HGF also activated AKT, while inhibition of AKT by LY294002 induced a modest decrease of HGF-induced HBMEC migration. These results highlight a model whereby JNK and ERK play a critical role in regulation of brain endothelial cell migration by HGF.