Constitutive activation of NF-kappaB causes resistance to apoptosis in human cutaneous T cell lymphoma HuT-78 cells. Autocrine role of tumor necrosis factor and reactive oxygen intermediates

The Role of Cytokines in Cutaneous T Cell Lymphoma: A Focus on the State of the Art and Possible Therapeutic Targets

Cutaneous T cell lymphomas (CTCLs), encompassing mycosis fungoides (MF) and Sézary syndrome (SS), present a complex landscape influenced by cytokines and cellular responses. In this work, the intricate relationship between these inflammatory proteins and disease pathogenesis is examined, focusing on what is known at the clinical and therapeutic levels regarding the most well-known inflammatory mediators. An in-depth look is given to their possible alterations caused by novel immunomodulatory drugs and how they may alter disease progression. From this narrative review of the actual scientific landscape, Interferon-gamma (IFN-γ) emerges as a central player, demonstrating a dual role in both promoting and inhibiting cancer immunity, but the work navigates through all the major interleukins known in inflammatory environments. Immunotherapeutic perspectives are elucidated, highlighting the crucial role of the cutaneous microenvironment in shaping dysfunctional cell trafficking, antitumor immunity, and angiogenesis in MF, showcasing advancements in understanding and targeting the immune phenotype in CTCL. In summary, this manuscript aims to comprehensively explore the multifaceted aspects of CTCL, from the immunopathogenesis and cytokine dynamics centred around TNF-α and IFN-γ to evolving therapeutic modalities. Including all the major known and studied cytokines in this analysis broadens our understanding of the intricate interplay influencing CTCL, paving the way for improved management of this complex lymphoma.

Cellular heterogeneity in TNF/TNFR1 signalling: live cell imaging of cell fate decisions in single cells

Cellular responses to TNF are inherently heterogeneous within an isogenic cell population and across different cell types. TNF promotes cell survival by activating pro-inflammatory NF-κB and MAPK signalling pathways but may also trigger apoptosis and necroptosis. Following TNF stimulation, the fate of individual cells is governed by the balance of pro-survival and pro-apoptotic signalling pathways. To elucidate the molecular mechanisms driving heterogenous responses to TNF, quantifying TNF/TNFR1 signalling at the single-cell level is crucial. Fluorescence live-cell imaging techniques offer real-time, dynamic insights into molecular processes in single cells, allowing for detection of rapid and transient changes, as well as identification of subpopulations, that are likely to be missed with traditional endpoint assays. Whilst fluorescence live-cell imaging has been employed extensively to investigate TNF-induced inflammation and TNF-induced cell death, it has been underutilised in studying the role of TNF/TNFR1 signalling pathway crosstalk in guiding cell-fate decisions in single cells. Here, we outline the various opportunities for pathway crosstalk during TNF/TNFR1 signalling and how these interactions may govern heterogenous responses to TNF. We also advocate for the use of live-cell imaging techniques to elucidate the molecular processes driving cell-to-cell variability in single cells. Understanding and overcoming cellular heterogeneity in response to TNF and modulators of the TNF/TNFR1 signalling pathway could lead to the development of targeted therapies for various diseases associated with aberrant TNF/TNFR1 signalling, such as rheumatoid arthritis, metabolic syndrome, and cancer.

Chronic inflammation and cancer; the two sides of a coin

The correlation between chronic inflammation and cancer was initially identified in the 19th century. Biomolecules like interleukins, chemokines, tumor necrosis factors, growth factors, and adhesion molecules, which regulate inflammation, are recognized contributors to neoplastic transformation through various mechanisms, including oncogenic mutations, resistance to apoptosis, and adaptive responses like angiogenesis. This review aims to establish connections between the intricate and complex mechanisms of chronic inflammation and cancer. We illuminate implicit signaling mechanisms that drive the association between chronic inflammation and the initiation/progression of cancer, exploring potential impacts on other diseases. Additionally, we discuss the modalities of currently available therapeutic options for chronic inflammation and cancer, emphasizing the dual nature of such therapies. A thorough understanding of the molecular basis of chronic inflammation is crucial for developing novel approaches in the prevention and treatment of cancer.

Molecular pathogenesis of Cutaneous T cell Lymphoma: Role of chemokines, cytokines, and dysregulated signaling pathways

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of lymphoproliferative neoplasms that exhibit a wide spectrum of immune-phenotypical, clinical, and histopathological features. The biology of CTCL is complex and remains elusive. In recent years, the application of next-generation sequencing (NGS) has evolved our understanding of the pathogenetic mechanisms, including genetic aberrations and epigenetic abnormalities that shape the mutational landscape of CTCL and represent one of the important pro-tumorigenic principles in CTCL initiation and progression. Still, identification of the major pathophysiological pathways including genetic and epigenetic components that mediate malignant clonal T cell expansion has not been achieved. This is of prime importance given the role of malignant T cell clones in fostering T helper 2 (Th2)-bias tumor microenvironment and fueling progressive immune dysregulation and tumor cell growth in CTCL patients, manifested by the secretion of Th2-associated cytokines and chemokines. Alterations in malignant cytokine and chemokine expression patterns orchestrate the inflammatory milieu and influence the migration dynamics of malignant clonal T cells. Here, we highlight recent insights about the molecular mechanisms of CTCL pathogenesis, emphasizing the role of cytokines, chemokines, and associated downstream signaling networks in driving immune defects, malignant transformation, and disease progression. In-depth characterization of the CTCL immunophenotype and tumoral microenvironment offers a facile opportunity to expand the therapeutic armamentarium of CTCL, an intractable malignant skin disease with poor prognosis and in dire need of curative treatment approaches.

Chronic Kidney Disease and Cancer: Inter-Relationships and Mechanisms

Chronic kidney disease (CKD) has been recognized as an increasingly serious public health problem globally over the decades. Accumulating evidence has shown that the incidence rate of cancer was relatively higher in CKD patients than that in general population, which, mechanistically, may be related to chronic inflammation, accumulation of carcinogenic compounds, oxidative stress, impairment of DNA repair, excessive parathyroid hormone and changes in intestinal microbiota, etc. And in patients with cancer, regardless of tumor types or anticancer treatment, it has been indicated that the morbidity and incidence rate of concomitant CKD was also increased, suggesting a complex inter-relationship between CKD and cancer and arousing increasing attention from both nephrologists and oncologists. This narrative review focused on the correlation between CKD and cancer, and underlying molecular mechanisms, which might provide an overview of novel interdisciplinary research interests and the potential challenges related to the screening and treatment of CKD and cancer. A better understanding of this field might be of help for both nephrologists and oncologists in the clinical practice.

Effect of PUVA and NB-UVB Therapy on the Skin Cytokine Profile in Patients with Mycosis Fungoides

Background. Mycosis fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma. The aim of the present study was to produce up-to-date information on different phototherapy approaches on skin cytokines in patients with MF. Methods. A total of 27 patients with mycosis fungoides were treated with phototherapy: NB-UVB (narrow‐band ultraviolet B therapy) (10 patients) and PUVA (long-wavelength ultraviolet radiation of spectrum A with the use of skin-photosensitizing furocoumarins) therapy (17 patients). Evaluation of the effectiveness of treatment was carried out using BSA (body surface area) and the modified assessment of the severity of the skin lesions scale (mSWAT) used to quantify tumor mass in cutaneous T-cell lymphomas. Average numbers of procedures were 30.2 and 27.8 in the NB-UVB and PUVA groups, respectively. The median total dose of NB-UVB irradiation was 19.9 J/cm2 and PUVA therapy was 104.0 J/cm2. The overall response to therapy including complete and partial remission was 74.9% in the total group; 70% in the NB-UVB group, and 77.7% in the PUVA therapy group. In the obtained biopsies from lesions, surrounding tissue before treatment and skin samples of four healthy volunteers, the concentration of the IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L, and TNF-α cytokines was studied. An increase in IL-4 and TNF-α levels was shown in the lesional skin of patients compared to the skin of healthy controls. After the treatment, positive correlations of mSWAT with the levels of IL22, IL33, and TNF-α in the tumor tissue were found. The levels of IL10 and IFN-γ after PUVA treatment were increased in comparison to baseline. There was no difference in cytokine levels before/after NB-UVB therapy.

Utilizing Immunocytokines for Cancer Therapy

Cytokine therapy for cancer has indicated efficacy in certain diseases but is generally accompanied by severe toxicity. The field of antibody-cytokine fusion proteins (immunocytokines) arose to target these effector molecules to the tumor environment in order to expand the therapeutic window of cytokine therapy. Pre-clinical evidence has shown the increased efficacy and decreased toxicity of various immunocytokines when compared to their cognate unconjugated cytokine. These anti-tumor properties are markedly enhanced when combined with other treatments such as chemotherapy, radiotherapy, and checkpoint inhibitor antibodies. Clinical trials that have continued to explore the potential of these biologics for cancer therapy have been conducted. This review covers the in vitro, in vivo, and clinical evidence for the application of immunocytokines in immuno-oncology.

LW-213 induces cell apoptosis in human cutaneous T-cell lymphomas by activating PERK-eIF2α-ATF4-CHOP axis

Cutaneous T-cell lymphoma (CTCL) is characterized by a heterogeneous group of extranodal non-Hodgkin lymphomas, in which monoclonal T lymphocytes infiltrate the skin. LW-213, a derivative of wogonin, was found to induce cell apoptosis in chronic myeloid leukemia (CML). In this study, we investigated the effects of LW-213 on CTCL cells and the underlying mechanisms. We showed that LW-213 (1-25 μM) dose-dependently inhibited human CTCL cell lines (Hut-102, Hut-78, MyLa, and HH) with IC₅₀ values of around 10 μM, meanwhile it potently inhibited primary leukemia cells derived from peripheral blood of T-cell lymphoma patients. We revealed that LW-213-induced apoptosis was accompanied by ROS formation and the release of calcium from endoplasmic reticulum (ER) through IP₃R-1channel. LW-213 selectively activated CHOP and induced apoptosis in Hut-102 cells via activating PERK-eIF2α-ATF4 pathway. Interestingly, the degree of apoptosis and expression of ER stress-related proteins were alleviated in the presence of either N-acetyl cysteine (NAC), an ROS scavenger, or 2-aminoethyl diphenylborinate (2-APB), an IP₃R-1 inhibitor, implicating ROS/calcium-dependent ER stress in LW-213-induced apoptosis. In NOD/SCID mice bearing Hut-102 cell line xenografts, administration of LW-213 (10 mg/kg, ip, every other day for 4 weeks) markedly inhibited the growth of Hut-102 derived xenografts and prolonged survival. In conclusion, our study provides a new insight into the mechanism of LW-213-induced apoptosis, suggesting the potential of LW-213 as a promising agent against CTCL.

Frequent and Persistent PLCG1 Mutations in Sézary Cells Directly Enhance PLCγ1 Activity and Stimulate NFκB, AP-1, and NFAT Signaling

Phospholipase C Gamma 1 (PLCG1) is frequently mutated in primary cutaneous T-cell lymphoma (CTCL). This study functionally interrogated nine PLCG1 mutations (p.R48W, p.S312L, p.D342N, p.S345F, p.S520F, p.R1158H, p.E1163K, p.D1165H, and the in-frame indel p.VYEEDM1161V) identified in Sézary Syndrome, the leukemic variant of CTCL. The mutations were demonstrated in diagnostic samples and persisted in multiple tumor compartments over time, except in patients who achieved a complete clinical remission. In basal conditions, the majority of the mutations confer PLCγ1 gain-of-function activity through increased inositol phosphate production and the downstream activation of NFκB, AP-1, and NFAT transcriptional activity. Phosphorylation of the p.Y783 residue is essential for the proximal activity of wild-type PLCγ1, but we provide evidence that activating mutations do not require p.Y783 phosphorylation to stimulate downstream NFκB, NFAT, and AP-1 transcriptional activity. Finally, the gain-of-function effects associated with the p.VYEEDM1161V indel suggest that the C2 domain may have a role in regulating PLCγ1 activity. These data provide compelling evidence to support the development of therapeutic strategies targeting mutant PLCγ1.

Analysis of the Effect of Gentian Violet on Apoptosis and Proliferation in Cutaneous T-Cell Lymphoma in an In Vitro Study

Importance

Triggering the extrinsic apoptotic pathway is an effective way to kill cutaneous T-cell lymphoma (CTCL) cells in vitro and ex vivo.

Objective

To compare small molecules that induce extrinsic apoptosis in CTCL to identify and analyze compounds that induce high levels of tumor cell death and block tumor cell growth.

Design, Setting, and Participants

From November 5, 2014, to January 30, 2018, this study performed high-throughput small molecule screening of 1710 compounds followed by detailed analysis of the ability of gentian violet (GV) to promote apoptosis and inhibit proliferation of CTCL cells.

Exposures

In vitro and ex vivo analyses using enzyme-linked immunosorbent assays, flow cytometry, and immunoblotting.

Main Outcomes and Measures

Apoptosis, cleaved caspases, extrinsic apoptotic death receptors and ligands, cell proliferation, nuclear factor-κB expression, and other factors.

Results

This study used high-throughput screening to detect cleaved caspase 8 induced in CTCL cells by 1710 unique compounds. The nonprescription, topical antimicrobial remedy GV induced more total apoptosis than did nitrogen mustard (mechlorethamine). Furthermore, GV induced 4 to 6 times greater apoptosis in CTCL lines than in normal keratinocytes, suggesting a favorable topical toxicity profile. In addition to increasing caspase 8, GV also upregulated death receptors 4 and 5, tumor necrosis factor (TNF)-related apoptosis-inducing ligand, and Fas ligand but not the Fas receptor, TNF receptor, or TNF-α ligand. These results are consistent with induction of extrinsic apoptosis via the Fas and TNF-related apoptosis-inducing ligand pathways. Increased phosphorylation of phospholipase C-γ1, Ca2+ influx, and reactive oxygen species were also detected, indicating that the mechanism of Fas ligand upregulation involves key elements of the activation-induced cell death pathway. In ex vivo studies, 1-μmol/L GV induced up to 90% CTCL apoptosis in Sézary blood cells. In addition, GV reduced expression of antiapoptotic myeloid cell leukemia 1 and proproliferative nuclear factor-κB components and increased inhibitory κB levels. This finding was associated with cell cycle arrest and reduced CTCL tumor cell proliferation. Furthermore, the CTCL killing associated with GV was augmented when used in combination with methotrexate.

Conclusions and Relevance

This study found that GV attacked tumor viability and growth in CTCL. Although purple at neutral pH, GV can be rendered colorless by altering its pH. These preclinical findings may help to broaden knowledge of the antineoplastic features of GV and provide a rationale for clinical studies of its use as a novel, inexpensive, topical therapy for CTCL that is available worldwide.

Genetics of Cutaneous T Cell Lymphoma: From Bench to Bedside

OPINION STATEMENT

Cutaneous T cell lymphomas (CTCLs) are non-Hodgkin lymphomas of skin homing T cells. Although early-stage disease may be limited to the skin, tumor cells in later stage disease can populate the blood, the lymph nodes, and the visceral organs. Unfortunately, there are few molecular biomarkers to guide diagnosis, staging, or treatment of CTCL. Diagnosis of CTCL can be challenging and requires the synthesis of clinical findings, histopathology, and T cell clonality studies; however, none of these tests are entirely sensitive or specific for CTCL. Treatment of CTCL is often empiric and is not typically based on specific molecular alterations, as is common in other cancers. In part, limitations in diagnosis and treatment selection reflect the limited insight into the genetic basis of CTCL. Recent next-generation sequencing has revolutionized our understanding of the mutational landscape in this disease. These analyses have uncovered ultraviolet radiation and recombination activating gene (RAG) endonucleases as important mutagens. Furthermore, these studies have revealed potentially targetable oncogenic mutations in the T cell receptor complex, NF-κB, and JAK-STAT signaling pathways. Collectively, these somatic mutations drive lymphomagenesis via cancer-promoting changes in proliferation, apoptosis, and T cell effector function. We expect that these genetic findings will launch a new era of precision medicine in CTCL.

The CRISPR/Cas9 system targeting EGFR exon 17 abrogates NF-κB activation via epigenetic modulation of UBXN1 in EGFRwt/vIII glioma cells

Worldwide, glioblastoma (GBM) is the most lethal and frequent intracranial tumor. Despite decades of study, the overall survival of GBM patients remains unchanged. epidermal growth factor receptor (EGFR) amplification and gene mutation are thought to be negatively correlated with prognosis. In this study, we used proteomics to determine that UBXN1 is a negative downstream regulator of the EGFR mutation vIII (EGFRvIII). Via bioinformatics analysis, we found that UBXN1 is a factor that can improve glioma patients' overall survival time. We also determined that the down-regulation of UBXN1 is mediated by the upregulation of H3K27me3 in the presence of EGFRvIII. Because NF-κB can be negatively regulated by UBXN1, we believe that EGFRwt/vIII activates NF-κB by suppressing UBXN1 expression. Importantly, we used the latest genomic editing tool, CRISPR/Cas9, to knockout EGFRwt/vIII on exon 17 and further proved that UBXN1 is negatively regulated by EGFRwt/vIII. Furthermore, knockout of EGFR/EGFRvIII could benefit GBM in vitro and in vivo, indicating that CRISPR/Cas9 is a promising therapeutic strategy for both EGFR amplification and EGFR mutation-bearing patients.

Anisakis pegreffii (Nematoda: Anisakidae) products modulate oxidative stress and apoptosis-related biomarkers in human cell lines

BACKGROUND

In countries with elevated prevalence of zoonotic anisakiasis and high awareness of this parasitosis, a considerable number of cases that associate Anisakis sp. (Nematoda, Anisakidae) and different bowel carcinomas have been described. Although neoplasia and embedded larvae were observed sharing the common site affected by chronic inflammation, no association between the nematode and malignancy were directly proved. Similarly, no data are available about the effect of secretory and excretory products of infecting larvae at the host's cellular level, except in respect to allergenic interaction.

METHODS

To test the mechanisms by which human non-immune cells respond to the larvae, we exposed the fibroblast cell line HS-68 to two Anisakis products (ES, excretory/secretory products; and EC, crude extract) and evaluated molecular markers related to stress response, oxidative stress, inflammation and apoptosis, such as p53, HSP70, TNF-α, c-jun and c-fos, employing cell viability assay, spectrophotometry, immunoblotting and qPCR.

RESULTS

Both Anisakis products led to increased production of reactive oxygen species (ROS), especially in EC-treated cells. While the ES treatment induces activation of kinases suggesting inflammation and cell proliferation (or inhibition of apoptosis), in EC-treated cells, other signaling pathways indicate the inhibition of apoptosis, marked by strong upregulation of Hsp70. Elevated induction of p53 in fibroblasts treated by both Anisakis products, suggests a significantly negative effect on the host DNA.

CONCLUSIONS

This study shows that in vitro cell response to Anisakis products can result in at least two different scenarios, which in both cases lead to inflammation and DNA damage. Although these preliminary results are far from proving a relationship between the parasite and cancer, they are the first to support the existence of conditions where such changes are feasible.

Simvastatin in combination with bergamottin potentiates TNF-induced apoptosis through modulation of NF-κB signalling pathway in human chronic myelogenous leukaemia

Context Simvastatin (SV) and bergamottin (BGM) are known to exhibit diverse anti-cancer and anti-inflammatory activities. Objective Very little is known about the potential efficacy of combination of these two agents to potentiate TNF-induced apoptosis in human chronic myelogenous leukaemia (CML). Materials and methods In the present study, we investigated whether SV combined with BGM mediates its effect through suppression of NF-κB-signalling pathway. Results We found that the combination treatment enhanced cytotoxicity and potentiated the apoptosis induced by TNF as indicated by intracellular esterase activity, Annexin V staining and caspase activation. This effect of co-treatment correlated with down-regulation of various gene products that mediate cell proliferation (cyclin D1), cell survival (cIAP-1, Bcl-2, Bcl-xL and Survivin), invasion (MMP-9) and angiogenesis (VEGF); all known to be regulated by NF-κB. SV combined with BGM also produced TNF-induced cell-cycle arrest in S-phase and this arrest correlated with a concomitant increase in the levels of cyclin-dependent inhibitor p21 and p27. The combination therapy inhibited TNF-induced NF-κB activation, IκBα degradation and p65 translocation to the nucleus as compared with the treatment with individual agents alone. Besides, SV combined with BGM did not significantly potentiate apoptotic effect induced by TNF in p65(-)(/)(-) cells, as compared with wild-type fibroblasts. Discussion and conclusion Our results provide novel insight into the role of SV and BGM in potentially preventing and treating cancer through modulation of NF-κB signalling pathway and its regulated gene products.

A role of ZnO nanoparticle electrostatic properties in cancer cell cytotoxicity

ZnO nanoparticles (NPs) have previously been shown to exhibit selective cytotoxicity against certain types of cancerous cells suggesting their potential use in biomedical applications. In this study, we investigate the effect of surface modification of ZnO NPs on their cytotoxicity to both cancerous and primary T cells. Our results show that polyacrylic acid capping produces negatively charged ZnO NPs that are significantly more toxic compared to uncapped positively charged NPs of identical size and composition. In contrast, the greatest selectivity against cancerous cells relative to normal cells is observed with cationic NPs. In addition, differences in NP cytotoxicity inversely correlate with NP hydrodynamic size, propensity for aggregation, and dissolution profiles. The generation of reactive oxygen species (ROS) was also observed in the toxicity mechanism with anionic NPs generating higher levels of mitochondrial superoxide without appreciably affecting glutathione levels. Additional experiments evaluated the combined effects of charged ZnO NPs and nontoxic cationic or anionic CeO₂ NPs. Results show that the CeO₂ NPs offer protective effects against cytotoxicity from anionic ZnO NPs via antioxidant properties. Altogether, study data indicate that surface modification of NPs and resulting changes in their surface charge affect the level of intracellular ROS production, which can be ameliorated by the CeO₂ ROS scavenger, suggesting that ROS generation is a dominant mechanism of ZnO NP cytotoxicity. These findings demonstrate the importance of surface electrostatic properties for controlling NP toxicity and illustrate an approach for engineering NPs with desired properties for potential use in biological applications.

2'-Hydroxy-4-methylsulfonylchalcone enhances TRAIL-induced apoptosis in prostate cancer cells

Prostate cancer is the most common malignant cancer in men and the second leading cause of cancer deaths. Previously, we have shown that 2'-hydroxy-4-methylsulfonylchalcone (RG003) induced apoptosis in prostate cancer cell lines PC-3 and DU145. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent, some cancer cells are resistant to TRAIL treatment. PC-3 and LNCaP prostatic cancer cell lines have been reported to be resistant to TRAIL-induced apoptosis. Here, we show for the first time that RG003 overcomes TRAIL resistance in prostate cancer cells. RG003 can enhance TRAIL-induced apoptosis through DR5 upregulation and downregulation of Bcl-2, PI3K/Akt, NF-κB, and cyclooxygenase-2 (COX-2) survival pathways. When used in combined treatment, RG003 and TRAIL amplified TRAIL-induced activation of apoptosis effectors and particularly activation of caspase-8 and the executioner caspase-3, leading to increased poly-ADP-ribose polymerase cleavage and DNA fragmentation in prostate cancer cells. Furthermore, we showed that RG003 reduced COX-2 expression in cells. Previously, we showed that COX-2 was involved in resistance to an apoptosis mechanism; then, its inhibition by RG003 could render cells more sensitive to TRAIL treatment. We showed that nuclear factor-κB activation was inhibited after RG003 treatment. This inhibition was correlated with reduction in COX-2 expression and induction of apoptosis. Overall, we conclude, for the first time, that RG003 can enhance TRAIL-induced apoptosis in human prostate cancer cells. The significance of our in-vitro study with RG003 and TRAIL combined is very encouraging, suggesting the relevance of testing this combined treatment in xenograft animal models.

Berberis libanotica extract targets NF-κB/COX-2, PI3K/Akt and mitochondrial/caspase signalling to induce human erythroleukemia cell apoptosis

The aim of this study was to describe and understand the relationship between cyclooxygenase-2 (COX-2) expression and apoptosis rate in erythroleukemia cells after apoptosis induction by Berberis libanotica (Bl) extract. To achieve this goal we used erythroleukemia cell lines expressing COX‑2 (HEL cell line) or not (K562 cell line). Moreover, we made use of COX‑2 cDNA to overexpress COX‑2 in K562 cells. In light of the reported chemopreventive and chemosensitive effects of natural products on various tumor cells and animal models, we postulated that our Bl extract may mediate their effects through apoptosis induction with suppression of cell survival pathways. Our study is the first report on the specific examination of intrinsic apoptosis and Akt/NF-κB/COX‑2 pathways in human erythroleukemia cells upon Bl extract exposure. Even if Bl extract induced apoptosis of three human erythroleukemia cell lines, a dominant effect of Bl extract treatment on K562 cells was observed resulting in activation of the late markers of apoptosis with caspase-3 activation, PARP cleavage and DNA fragmentation. Whereas, we showed that Bl extract reduced significantly expression of COX‑2 by a dose-dependent manner in HEL and K562 (COX‑2+) cells. Furthermore, in regard to our results, it is clear that the simultaneous inhibition of Akt and NF-κB signalling can significantly contribute to the anticancer effects of Bl extract in human erythroleukemia cells. We observed that the Bl extract is clearly more active than the berberine alone on the induction of DNA fragmentation in human erythro-leukemia cells.

Bortezomib inhibits expression of TGF-β1, IL-10, and CXCR4, resulting in decreased survival and migration of cutaneous T cell lymphoma cells

Increased expression of the immunosuppressive cytokines, TGF-β1 and IL-10, is a hallmark of the advanced stages of cutaneous T cell lymphoma (CTCL), where it has been associated with suppressed immunity, increased susceptibility to infections, and diminished antitumor responses. Yet, little is known about the transcriptional regulation of TGF-β1 and IL-10 in CTCL, and about their function in regulating the CTCL cell responses. In this article, we show that TGF-β1 and IL-10 expression in CTCL cells is regulated by NF-κB and suppressed by bortezomib (BZ), which has shown promising results in the treatment of CTCL. However, although the TGF-β1 expression is IκBα dependent and is regulated by the canonical pathway, the IL-10 expression is IκBα independent, and its inhibition by BZ is associated with increased promoter recruitment of p52 that characterizes the noncanonical pathway. TGF-β1 suppression decreases CTCL cell viability and increases apoptosis, and adding exogenous TGF-β1 increases viability of BZ-treated CTCL cells, indicating TGF-β1 prosurvival function in CTCL cells. In addition, TGF-β1 suppression increases expression of the proinflammatory cytokines IL-8 and IL-17 in CTCL cells, suggesting that TGF-β1 also regulates the IL-8 and IL-17 expression. Importantly, our results demonstrate that BZ inhibits expression of the chemokine receptor CXCR4 in CTCL cells, resulting in their decreased migration, and that the CTCL cell migration is mediated by TGF-β1. These findings provide the first insights into the BZ-regulated TGF-β1 and IL-10 expression in CTCL cells, and indicate that TGF-β1 has a key role in regulating CTCL survival, inflammatory gene expression, and migration.

Insulin-like growth factor binding protein-3 enhances etoposide-induced cell growth inhibition by suppressing the NF-κB activity in gastric cancer cells

Nuclear factor-kappaB (NF-κB) is a transcription factor that is activated in various neoplasms, including gastric cancer. Insulin-like growth factor binding protein-3 (IGFBP-3) is a potent tumor suppressor and is significantly suppressed in a variety of cancers. Although IGFBP-3 has been reported to have antiproliferative and proapoptotic effects, the precise mechanisms underlying the action of IGFBP-3 have not been elucidated. In this study, we found an inverse correlation between NF-κB activity and IGFBP-3 expression in patients with gastric cancer. Overexpression of IGFBP-3 resulted in significant inhibition of total and phosphorylated p65 NF-κB and IκB proteins in gastric cancer cells. IGFBP-3 further inhibited the expression of NF-κB-regulated cell adhesion molecules, ICAM-1 and VCAM-1. Finally, the growth inhibition induced by etoposide was significantly enhanced by IGFBP-3 overexpression along with concomitant suppression of NF-κB activity. These findings indicate that IGFBP-3 enhances etoposide-induced cell growth inhibition by blocking the NF-κB signaling pathway in gastric cancer cells. Furthermore, our data suggest that IGFBP-3 could be used as an adjuvant in the treatment of gastric cancer.

Mitochondrial dysfunction in cancer

Mitochondria are semi-autonomous organelles of eukaryotic cells. They perform crucial functions such as generating most of the cellular energy through the oxidative phosphorylation (OXPHOS) system and some other metabolic processes. In addition, mitochondria are involved in regulation of cell death and reactive oxygen species (ROS) generation. Also, mitochondria play important roles in carcinogenesis via altering energy metabolism, resistance to apoptosis, increase of production of ROS and mtDNA (mitochondrial genome) changes. Studies have suggested that aerobic glycolysis is high in malignant tumors. Probably, it correlates with high glucose intake of cancerous tissues. This observation is contrary to Warburg's theory that the main way of energy generation in cancer cells is non-oxidative glycolysis. Further studies have suggested that in tumor cells both oxidative phosphorylation and glycolysis were active at various rates.

An increase of intracellular oxidative stress induces damage of cellular structure and somatic mutations. Further studies confirmed that permanent activity of oxidative stress and the influence of chronic inflammation damage the healthy neighboring epithelium and may lead to carcinogenesis. For instance, chronic inflammatory bowel disease could be related to high risk of colon adenocarcinoma.

The data have shown a role of ROS generation, mtDNA or nDNA alterations and abnormal apoptotic machinery in endometrial cancer progress. Recent studies suggest that mtDNA mutations might play a potential role in endometrial cancer progress and indicate an increase of mitochondrial biogenesis in this cancer. The investigators suggested that MtCOI and MtND6 alteration has an influence on assembly of respiratory complexes in endometrial cancer.

In many human cancers, there is a deregulation of the balance between cell growth and death. The tumor cells can avoid apoptosis through a loss of balance between anti- and pro-apoptotic proteins, reduced caspase function and impaired death receptor signaling. Over-expression of the anti-apoptotic BCL-2 gene has also been identified in numerous cancers including colon, thyroid, breast and endometrial cancer. Most studies have found low BCL-2 family gene expression, which could be a sign of blocking apoptosis in breast and endometrial cancer. Moreover, BCL-2 gene expression is correlated with the degree of aggressiveness and differentiation in endometrial cancer. As a result, it could be a valuable predictor of disease progression.

Modulation of apoptosis-related cell signalling pathways by curcumin as a strategy to inhibit tumor progression

A hallmark of cancer is resistance to apoptosis, with both the loss of proapoptotic signals and the gain of anti-apoptotic mechanisms contributing to tumorigenesis. As inducing apoptosis in malignant cells is one of the most challenging tasks regarding cancer, researchers increasingly focus on natural products to regulate apoptotic signaling pathways. Curcumin, a polyphenolic derivative of turmeric, is a natural compound derived from Curcuma longa, has attracted great interest in the research of cancer during the last half century. Extensive studies revealed that curcumin has chemopreventive properties, which are mainly due to its ability to arrest cell cycle and to induce apoptosis in cancer cells either alone or in combination with chemotherapeutic agents or radiation. The underlying action mechanisms of curcumin are diverse and has not been elucidated so far. By regulating multiple important cellular signalling pathways including NF-κB, TRAIL, PI3 K/Akt, JAK/STAT, Notch-1, JNK, etc., curcumin are known to activate cell death signals and induce apoptosis in pre-cancerous or cancer cells without affecting normal cells, thereby inhibiting tumor progression. Several phase I and phase II clinical trials indicate that curcumin is quite safe and may exhibit therapeutic efficacy. This article reviews the main effects of curcumin on the different apoptotic signaling pathways involved in curcumin induced apoptosis in cancer cells via cellular transduction pathways and provides an in depth assessment of its pharmacological activity in the management of tumor progression.

Analysis of TGFβ1 and IL-10 transcriptional regulation in CTCL cells by chromatin immunoprecipitation

The immunosuppressive cytokines transforming growth factor β1 (TGFβ1) and interleukin-10 (IL-10) regulate a variety of biological processes including differentiation, proliferation, tissue repair, tumorigenesis, inflammation, and host defense. Aberrant expression of TGFβ1 and IL-10 has been associated with many types of autoimmune and inflammatory disorders, as well as with many types of cancer and leukemia. Patients with cutaneous T cell lymphoma (CTCL) have high levels of malignant CD4+ T cells expressing IL-10 and TGFβ1 that suppress the immune system and diminish the antitumor responses. The transcriptional regulation of TGFβ1 and IL-10 expression is orchestrated by several transcription factors, including NFκB. However, while the transcriptional regulation of pro-inflammatory and anti-apoptotic genes by NFκB has been studied extensively, much less is known about the NFκB regulation of immunosuppressive genes. In this chapter, we describe a protocol that uses chromatin immunoprecipitation (ChIP) to analyze the transcriptional regulation of TGFβ1 and IL-10 by measuring recruitment of NFκB p65, p50, c-Rel, Rel-B, and p52 subunits to TGFβ1 and IL-10 promoters in human CTCL Hut-78 cells.

Digitoflavone inhibits IκBα kinase and enhances apoptosis induced by TNFα through downregulation of expression of nuclear factor κB-regulated gene products in human pancreatic cancer cells

Tumor necrosis factor-α (TNFα) activates both cell death and cell survival pathways. The activation of survival pathway renders most cancer cells resistant to TNF-induced cytotoxicity. We found that pretreatment with digitoflavone, a plant flavonoid, greatly sensitized TNFα-induced apoptotic cell death in several human pancreatic cancer cells. In search of the molecular basis of the sensitization effect of digitoflavone, digitoflavone was found to inhibit TNFα-induced activation of nuclear transcription factor-kappa B (NF-κB) which is the main survival factor in TNFα signaling. NF-κB suppression occurred through inhibition of IκBα kinase activation, IκBα phosphorylation, IκBα degradation, and NF-κB nuclear translocation. This inhibition correlated with suppression of NF-κB-dependent genes involved in antiapoptosis (mcl-1, bcl-2, bcl-xl, c-iap1, c-iap2, flip, and survivin), proliferation (c-myc, cyclin d1), and angiogenesis (vegf, cox-2, and mmp-9). In addition, digitoflavone can activate JNK through inhibition of NF-κB signaling, provide a continuous blockade of the feed-back inhibitory mechanism by JNK-induced NF-κB activation. This study found a novel function of digitoflavone and enhanced the value of digitoflavone as an anticancer agent.

Regulation of Btg2(/TIS21/PC3) expression via reactive oxygen species-protein kinase C-ΝFκΒ pathway under stress conditions

Human B-cell translocation gene 2 (BTG2), an ortholog of mouse TIS21 (12-O-tetradecanoyl phorbol-13-acetate inducible sequence 21) and rat PC3 (Pheochromocytoma Cell 3), is a tumor suppressor gene that belongs to an antiproliferative gene family. Btg2 is involved in a variety of biological processes including cell growth, development, differentiation, senescence, and cell death and its expression is strongly regulated by p53. Recently, we have reported transient induction of Btg2 expression in response to oxidative damage; however, the regulatory mechanism was not explored. In the present study we revealed ΝFκΒ as the upstream mediator involved in Btg2 transcription in response to cell stress challenges such as serum deprivation and oxidative stress i.e. H2O2, TPA or doxorubicin treatments in several cell lines. We observed close interrelation between generation of reactive oxygen species (ROS), enhanced IκBα degradation, nuclear translocation of ΝFκΒ (p65/RelA) and the significant increase of Btg2 expression independent of p53 status. ChIP analysis revealed an enrichment of RelA (p65) bound to the κB response element on Btg2 promoter in response to the cell stress challenges. Employing various inhibitors led to cytoplasmic accumulation of IκBα, decreased p65 nuclear translocation along with significant reduction of Btg2 expression. Generation of ROS was the common event mediating ΝFκΒ activation and Btg2 transcription. Furthermore, PKC activation was also found to be a critical factor mediating ROS-mediated signals to NFκB pathway that culminate on Btg2 regulation, and specifically PKC-δ was responsible for this regulation under oxidative stress. However, serum deprivation-associated ROS generation bypassed PKC activation for induction of Btg2 expression via NFκB activation. The present data imply that oxidative stress upregulates Btg2 expression via ROS-PKC-ΝFκΒ cascade, independent of p53 status that in turn could be involved in mediating various biological phenotypes depending on the cellular context.

Novel methylsulfonyl chalcones as potential antiproliferative drugs for human prostate cancer: involvement of the intrinsic pathway of apoptosis

Limited success has been achieved in extending the survival of patients with metastatic and hormone-refractory prostate cancer (HRPC). There is a strong need for novel agents in the treatment and prevention of HRPC. In the present study, the apoptotic mechanism of action of RG003 (2'-hydroxy-4-methylsulfonylchalcone) and RG005 (4'-chloro-2'-hydroxy-4-methylsulfonylchalcone) in association with intracellular signalling pathways was investigated in the hormone-independent prostate carcinoma cells PC-3 and DU145. We showed that these compounds induced apoptosis through the intrinsic pathway but not through the extrinsic one. We showed that synthetic chalcones induced an activation of caspase-9 but not caspase-8 in PC-3 cells. Even if both chalcones induced apoptosis in PC-3 cells, a dominant effect of RG003 treatment was observed resulting in a disruption of ∆ψm, caspase-9 and caspase-3 activation, PARP cleavage and DNA fragmentation. Furthermore, in regard to our results, it is clear that the simultaneous inhibition of Akt and NF-κB signalling can significantly contribute to the anticancer effects of RG003 and RG005 in PC-3 prostate cancer cells. NF-κB inhibition was correlated with the reduction of COX-2 expression and induction of apoptosis. Our results clearly indicate for the first time that RG003 and RG005 exert their potent anti‑proliferative and pro-apoptotic effects through the modulation of Akt/NF-κB/COX-2 signal transduction pathways in PC-3 prostate cancer cells with a dominant effect for RG003.

Selectively targeting the toll-like receptor 9 (TLR9)--IRF 7 signaling pathway by polymer blend particles

Signaling through toll-like receptor 9 (TLR9) has been exploited for cancer therapy. The stimulation of TLR9 leads to two bifurcating signaling pathways - NF-κB-dependent pro-inflammatory cytokines pathway and IRF-7-dependent type I interferons (IFNs) pathway. In this study, we employ polymer blend particles to present the synthetic ligand, CpG oligonucleotides (CpG ODNs), to TLR9. The polymer blend particles are made from the blend of pH-insensitive and pH-sensitive copolymer. By tailoring the composition of the pH-sensitive polymer, CpG ODNs are presented to TLR9 in a way that only activates the IRF-7 signaling pathway. CpG ODNs have been used for cancer therapy in both preclinical and clinical studies. The selective activation of IRF-7 could potentially enhance the apoptosis of tumor cells and immunological control of tumor progression without inadvertently activating NF-κB-dependent oncogenesis.

Clusterin confers resistance to TNF-alpha-induced apoptosis in breast cancer cells through NF-kappaB activation and Bcl-2 overexpression

Secretory clusterin (sClu) is an anti-apoptotic protein that plays a role in protecting cells from Tumour-necrosis factor (TNF)-alpha-induced apoptosis. The aim of the present study was to investigate the molecular mechanisms underlying the effect of sClu on TNF-alpha-induced apoptosis in breast cancer cells. The wild-type p53 expressing MCF-7 cell line was engineered to overexpress sClu (MCF-7/sClu), whereas the MDA-MB-231 cell line with mutant p53 was transfected with a sClu silencing siRNA (MDA-MB-231/sClu siRNA). The effects of clusterin overexpression and downregulation on apoptosis and sensitivity to TNF-alpha were examined in vitro. Our results showed that TNF-alpha treatment increased Bcl-2 mRNA and protein levels in breast cancer cells, suggesting that Bcl-2 is directly regulated by nuclear factor-kappaB (NF-kappaB) in response to TNF-alpha. The induction of Bcl-2 was mediated by the p65 subunit of NF-kappaB. siRNA-mediated silencing of Bcl-2 led to a significant increase in TNF-alpha-induced apoptosis. Silencing of sClu in MDA-MB-231/sClu siRNA cells abrogated TNF-alpha-mediated NF-kappaB activation and Bcl-2 overexpression, and rendered the MDA-MB-231/sClu siRNA cells significantly more sensitive to TNF-alpha-mediated apoptosis than the parental cells. Furthermore, overexpression of sClu in MCF-7/sClu cells promoted TNF-alpha-mediated NF-kappaB activity and Bcl-2 overexpression, and rendered the MCF-7/Clu cells significantly more resistant to TNF-alpha-mediated apoptosis. Inhibition of NF-kappaB activity or p65 and Bcl-2 expression reversed these effects. The present results suggested that sClu confers breast cancer cells resistance to TNF-alpha-induced apoptosis through NF-kappaB activation and Bcl-2 overexpression.

Role of nuclear factor-ĸB in breast and colorectal cancer

The purpose of this review article is to highlight articles and new research regarding the link between NF-ĸB and several cancers. This review presents the most up-to-date NF-ĸB research and how it links this important transcription factor with hematology and oncology. It was written by conducting a thorough search of Pubmed as well as several journals such as Cancer, Nature, Science, Cell and those of one of the authors. The articles relating to the link between NF-ĸB and cancer were used to write this review. The results of this study clarified that there is a critical link between NF-ĸB and cancer. NF-ĸB has often been implicated in a variety of different diseases and it plays a variety of roles in cell survival, differentiation, and proliferation of cells. In cancer, NF-ĸB plays a pivotal role by facilitating oncogenesis as well as metastasis. A thorough understanding of NF-ĸB and its role in cancer can lead to future studies and drug development which could provide a novel option in the treatment of this disease.

Cyclopamine and jervine induce COX-2 overexpression in human erythroleukemia cells but only cyclopamine has a pro-apoptotic effect

Erythroleukemia is generally associated with a very poor response and survival to current available therapeutic agents. Cyclooxygenase-2 (COX-2) has been described to play a crucial role in the proliferation and differentiation of leukemia cells, this enzyme seems to play an important role in chemoresistance in different cancer types. Previously, we demonstrated that diosgenin, a plant steroid, induced apoptosis in HEL cells with concomitant COX-2 overexpression. In this study, we investigated the antiproliferative and apoptotic effects of cyclopamine and jervine, two steroidal alkaloids with similar structures, on HEL and TF1a human erythroleukemia cell lines and, for the first time, their effect on COX-2 expression. Cyclopamine, but not jervine, inhibited cell proliferation and induced apoptosis in these cells. Both compounds induced COX-2 overexpression which was responsible for apoptosis resistance. In jervine-treated cells, COX-2 overexpression was NF-κB dependent. Inhibition of NF-κB reduced COX-2 overexpression and induced apoptosis. In addition, cyclopamine induced apoptosis and COX-2 overexpression via PKC activation. Inhibition of the PKC pathway reduced both apoptosis and COX-2 overexpression in both cell lines. Furthermore, we demonstrated that the p38/COX-2 pathway was involved in resistance to cyclopamine-induced apoptosis since p38 inhibition reduced COX-2 overexpression and increased apoptosis in both cell lines.

Molecular mechanisms of curcumin action: gene expression

Curcumin derived from the tropical plant Curcuma longa has a long history of use as a dietary agent, food preservative, and in traditional Asian medicine. It has been used for centuries to treat biliary disorders, anorexia, cough, diabetic wounds, hepatic disorders, rheumatism, and sinusitis. The preventive and therapeutic properties of curcumin are associated with its antioxidant, anti-inflammatory, and anticancer properties. Extensive research over several decades has attempted to identify the molecular mechanisms of curcumin action. Curcumin modulates numerous molecular targets by altering their gene expression, signaling pathways, or through direct interaction. Curcumin regulates the expression of inflammatory cytokines (e.g., TNF, IL-1), growth factors (e.g., VEGF, EGF, FGF), growth factor receptors (e.g., EGFR, HER-2, AR), enzymes (e.g., COX-2, LOX, MMP9, MAPK, mTOR, Akt), adhesion molecules (e.g., ELAM-1, ICAM-1, VCAM-1), apoptosis related proteins (e.g., Bcl-2, caspases, DR, Fas), and cell cycle proteins (e.g., cyclin D1). Curcumin modulates the activity of several transcription factors (e.g., NF-κB, AP-1, STAT) and their signaling pathways. Based on its ability to affect multiple targets, curcumin has the potential for the prevention and treatment of various diseases including cancers, arthritis, allergies, atherosclerosis, aging, neurodegenerative disease, hepatic disorders, obesity, diabetes, psoriasis, and autoimmune diseases. This review summarizes the molecular mechanisms of modulation of gene expression by curcumin.

Systemic TNFα gene therapy synergizes with liposomal doxorubicine in the treatment of metastatic cancer

Tumor necrosis factor alpha (TNFα) is a potent antitumoral cytokine, either killing tumor cells directly or affecting the tumor vasculature leading to enhanced accumulation of macromolecular drugs. Due to dose limiting side effects systemic administration of TNFα protein at therapeutically active doses is precluded. With gene vectors, tumor restricted TNFα expression can be achieved and in principle synergize with chemotherapy. Synthetic gene carriers based on polyamines were intravenously injected, which either passively accumulate within the tumor or specifically target the epidermal growth factor receptor. A single intravenous injection of TNFα gene vector promoted accumulation of liposomal doxorubicine (Doxil) in murine neuroblastoma and human hepatoma by enhancing tumor endothelium permeability. The expression of transgenic TNFα was restricted to tumor tissue. Three treatment cycles with TNFα gene vectors and Doxil significantly delayed tumor growth in subcutaneous murine Neuro2A neuroblastoma. Also tumors re-growing after initial treatment were successfully treated in a fourth cycle pointing at the absence of resistance mechanisms. Systemic Neuro2A metastases or human LS174T colon carcinoma metastases in liver were also successfully treated with this combined approach. In conclusion, this schedule opens the possibility for the efficient treatment of tumors metastases otherwise not accessible for macromolecular drug carriers.

Toxicarioside A inhibits SGC-7901 proliferation, migration and invasion via NF-κB/bFGF signaling

AIM: To investigate the inhibitory role of toxicarioside A on the gastric cancer cell line human gastric cancer cell line (SGC-7901) and determine the underlying molecular mechanism.

METHODS: After SGC-7901 cells were treated with toxicarioside A at various concentrations (0.5, 1.5, 4.5, 9.0 μg/mL) for 24 h or 48 h, cell viability was determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay, and the motility and invasion of tumor cells were assessed by the Transwell chamber assay. Immunofluorescence staining, reverse transcription polymerase chain reaction and Western blotting were performed to detect the expression of basic fibroblast growth factor (bFGF) and fibroblast growth factor receptor-1 (FGFR1), and nuclear factor-kappa B (NF-κB) activation was examined by electrophoretic mobility shift assay.

RESULTS: The results showed that toxicarioside A was capable of reducing cell viability, inhibiting cell growth, and suppressing cell migration and invasion activities in a time- and dose-dependent manner in SGC-7901 cells. Further analysis revealed that not only the expression of bFGF and its high-affinity receptor FGFR1 but also the NF-κB-DNA binding activity were effectively blocked by toxicarioside A in a dose-dependent manner compared with the control group (P < 0.05 or P < 0.01). Interestingly, application of the NF-κB specific inhibitor, pyrrolidinedithiocarbamate (PDTC), to SGC-7901 cells significantly potentized the toxicarioside A-induced down-regulation of bFGF compared with the control group (P < 0.05).

CONCLUSION: These findings suggest that toxicarioside A has an anti-gastric cancer activity and this effect may be achieved partly through down-regulation of NF-κB and bFGF/FGFR1 signaling.

Nuclear factor-kappa B inhibitors; a patent review (2006-2010)

INTRODUCTION

Nuclear factor (NF)-κB, as transcription factor, is linked to the expression of various genes and plays an essential role in immune and inflammatory responses. Abnormal NF-κB signaling results in human diseases, such as immune disorders, inflammation and various cancers. Therefore, regulation of NF-κB may treat or improve the symptoms in human disorders.

AREAS COVERED

This review provides information on recent NF-κB inhibitor-related patents from 2006 to 2010. The patents are explained and categorized by mechanism. The reader will gain an understanding of NF-κB function and the structure and biological activity of recently developed NF-κB inhibitors that may be new drug candidates.

EXPERT OPINION

NF-κB plays an essential role in the human body and thus regulation of NF-κB is very important for the treatment of diseases. Furthermore, patented compounds and peptides are available as lead compounds in drug development studies.

Signal transduction by tumor necrosis factor receptors

Tumor necrosis factor (TNF) is a key mediator in the inflammatory response which is implicated in the onset of a number of diseases. Research on TNF led to the characterization of the largest family of cytokines known until now, the TNF superfamily, which exert their biological effects through the interaction with transmembrane receptors of the TNFR superfamily. TNF itself exerts its biological effects interacting with two different receptors: TNFR1 and TNFR2. TNFR1 presents a death domain on its intracellular region. In contrast to TNFR1, TNFR2 does not have a death domain. Activation of TNFR1 implies the consecutive formation of two different TNF receptor signalling complexes. Complex I controls the expression of antiapoptotic proteins that prevent the triggering of cell death processes, whereas Complex II triggers cell death processes. TNFR2 only signals for antiapoptotic reactions. However, recent evidence indicates that TNFR2 also signals to induce TRAF2 degradation. TRAF2 is a key mediator in signal transduction of both TNFR1 and TNFR2. Thus, this novel signalling pathway has two important implications: on one hand, it represents an auto regulatory loop for TNFR2; on the other hand, when this signal is triggered TNFR1 activity is modified so that antiapoptotic pathways are inhibited and apoptotic reactions are enhanced.

Plumbagin inhibits cell growth and potentiates apoptosis in human gastric cancer cells in vitro through the NF-κB signaling pathway

AIM

To investigate the effects and underlying mechanisms of plumbagin, a naphthoquinone derived from medicinal plant Plumbago zeylanica, on human gastric cancer (GC) cells.

METHODS

Human gastric cancer cell lines SGC-7901, MKN-28, and AGS were used. The cell viability was examined using CCK-8 viability assay. Cell proliferation rate was determined using both clonogenic assay and EdU incorporation assay. Apoptosis was detected via Annexin V/propidium iodide double-labeled flow cytometry. Western blotting was used to assess the expression of both NF-κB-regulated gene products and TNF-α-induced activation of p65, IκBα, and IKK. The intracellular location of NF-κB p65 was detected using confocal microscopy.

RESULTS

Plumbagin (2.5-40 μmol/L) concentration-dependently reduced the viability of the GC cells. The IC(50) value of plumbagin in SGC-7901, MKN-28, and AGS cells was 19.12, 13.64, and 10.12 μmol/L, respectively. The compound (5-20 μmol/L) concentration-dependently induced apoptosis of SGC-7901 cells, and potentiated the sensitivity of SGC-7901 cells to chemotherapeutic agents TNF-αand cisplatin. The compound (10 μmol/L) downregulated the expression of NF-κB-regulated gene products, including IAP1, XIAP, Bcl-2, Bcl-xL, tumor factor (TF), and VEGF. In addition to inhibition of NF-κB p65 nuclear translocation, the compound also suppressed TNF-α-induced phosphorylation of p65 and IKK, and the degradation of IκBα.

CONCLUSION

Plumbagin inhibits cell growth and potentiates apoptosis in human GC cells through the NF-κB pathway.

Nox4 mediates renal cell carcinoma cell invasion through hypoxia-induced interleukin 6- and 8- production

Background

Inflammatory cytokines are detected in the plasma of patients with renal cell carcinoma (RCC) and are associated with poor prognosis. However, the primary cell type involved in producing inflammatory cytokines and the biological significance in RCC remain unknown. Inflammation is associated with oxidative stress, upregulation of hypoxia inducible factor 1-alpha, and production of pro-inflammatory gene products. Solid tumors are often heterogeneous in oxygen tension together suggesting that hypoxia may play a role in inflammatory processes in RCC. Epithelial cells have been implicated in cytokine release, although the stimuli to release and molecular mechanisms by which they are released remain unclear. AMP-activated protein kinase (AMPK) is a highly conserved sensor of cellular energy status and a role for AMPK in the regulation of cell inflammatory processes has recently been demonstrated.

Methods and Principal Findings

We have identified for the first time that interleukin-6 and interleukin-8 (IL-6 and IL-8) are secreted solely from RCC cells exposed to hypoxia. Furthermore, we demonstrate that the NADPH oxidase isoform, Nox4, play a key role in hypoxia-induced IL-6 and IL-8 production in RCC. Finally, we have characterized that enhanced levels of IL-6 and IL-8 result in RCC cell invasion and that activation of AMPK reduces Nox4 expression, IL-6 and IL-8 production, and RCC cell invasion.

Conclusions/Significance

Together, our data identify novel mechanisms by which AMPK and Nox4 may be linked to inflammation-induced RCC metastasis and that pharmacological activation of AMPK and/or antioxidants targeting Nox4 may represent a relevant therapeutic intervention to reduce IL-6- and IL-8-induced inflammation and cell invasion in RCC.

Mesothelin confers pancreatic cancer cell resistance to TNF-α-induced apoptosis through Akt/PI3K/NF-κB activation and IL-6/Mcl-1 overexpression

Background

Previous studies showed that mesothelin (MSLN) plays important roles in survival of pancreatic cancer (PC) cells under anchorage dependent/independent conditions as well as resistance to chemotherapy. The recent success of intratumorally-injected adeno-encoded, chemo/radiation-inducible-promoter driven hTNF-α, (TNFerade) + gemcitabine in pre-clinical models of PC have renewed interest in use of TNF-α as a therapeutic component. To help find additional factors which might affect the therapy, we examined the resistance of MSLN-overexpressing pancreatic cancer cell lines to TNF-α-induced growth inhibition/apoptosis.

Methods

Stable MSLN overexpressing MIA PaCa-2 cells (MIA-MSLN), stable MSLN-silenced AsPC-1 cells (AsPC-shMSLN) and other pancreatic cells (MIA-PaCa2, Panc 28, Capan-1, BxPC3, PL 45, Hs 766T, AsPC-1, Capan-2, Panc 48) were used. NF-κB activation was examined by western blots and luciferase reporter assay. TNF-α induced growth inhibition/apoptosis was measured by MTT, TUNEL assay and caspase activation. IL-6 was measured using luminex based assay.

Results

Compared to low endogenous MSLN-expressing MIA PaCa-2 and Panc 28 cells, high endogenous MSLN-expressing Capan-1, BxPC3, PL 45, Hs 766T, AsPC-1, Capan-2, Panc 48 cells were resistant to TNF-α induced growth inhibition. Stable MSLN overexpressing MIA-PaCa2 cells (MIA-MSLN) were resistant to TNF-α-induced apoptosis while stable MSLN-silenced AsPC1 cells (AsPC-shMSLN) were sensitive. Interestingly, TNF-α-treated MIA-MSLN cells showed increased cell cycle progression and cyclin A induction, both of which were reversed by caspase inhibition. We further found that MIA-MSLN cells showed increased expression of anti-apoptotic Bcl-XL and Mcl-1; deactivated (p-Ser⁷⁵) BAD, and activated (p-Ser⁷⁰) Bcl-2. Constitutively activated NF-κB and Akt were evident in MIA-MSLN cells that could be suppressed by MSLN siRNA with a resultant increase in sensitivity of TNF-α induced apoptosis. Blocking NF-κB using IKK inhibitor wedelolactone also increased sensitivity to TNF-α-mediated cytotoxicity with concomitant decrease in Mcl-1. Blocking Akt using PI3K inhibitor also had a likewise effect presumably affecting cell cycle. MIA-MSLN cells produced increased IL-6 and were increased furthermore by TNF-α treatment. SiRNA-silencing of IL-6 increased TNF-α sensitivity of MIA-MSLN cells.

Conclusions

Our study delineates a MSLN-Akt-NF-κB-IL-6-Mcl-1 survival axis that may be operative in PC cells, and might help cancer cells' survival in the highly inflammatory milieu evident in PC. Further, for the success of TNFerade + gemcitabine to be successful, we feel the simultaneous inhibition of components of this axis is also essential.

Triptolide, histone acetyltransferase inhibitor, suppresses growth and chemosensitizes leukemic cells through inhibition of gene expression regulated by TNF-TNFR1-TRADD-TRAF2-NIK-TAK1-IKK pathway

Triptolide, a diterpene triepoxide, from the Chinese herb Tripterygium wilfordii Hook.f, exerts its anti-inflammatory and immunosuppressive activities by inhibiting the transcription factor nuclear factor-κB (NF-κB) pathway, through a mechanism not yet fully understood. We found that triptolide, in nanomolar concentrations, suppressed both constitutive and inducible NF-κB activation, but did not directly inhibit binding of p65 to the DNA. The diterpene did block TNF-induced ubiquitination, phosphorylation, and degradation of IκBα, the inhibitor of NF-κB and inhibited acetylation of p65 through suppression of binding of p65 to CBP/p300. Triptolide also inhibited the IκBα kinase (IKK) that activates NF-κB and phosphorylation of p65 at serine 276, 536. Furthermore, the NF-κB reporter activity induced by TNF-TNFR1-TRADD-TRAF2-NIK-TAK1-IKKβ was abolished by the triepoxide. Triptolide also abrogated TNF-induced expression of cell survival proteins (XIAP, Bcl-x(L), Bcl-2, survivin, cIAP-1 and cIAP-2), cell proliferative proteins (cyclin D1, c-myc and cyclooxygenase-2), and metastasis proteins (ICAM-1 and MMP-9). This led to enhancement of apoptosis induced by TNF, taxol, and thalidomide by the diterpene and to suppression of tumor invasion. Overall, our results demonstrate that triptolide can block the inflammatory pathway activated by TNF-TNFR1-TRADD-TRAF2-NIK-TAK1-IKK, sensitizes cells to apoptosis, and inhibits invasion of tumor cells.

Glucocorticoid receptor alpha isoform-selective regulation of antiapoptotic genes in osteosarcoma cells: a new mechanism for glucocorticoid resistance

Glucocorticoids regulate a variety of physiological processes and are commonly used to treat disorders of inflammation, autoimmune diseases, and cancer. Glucocorticoid action is predominantly mediated through the classic glucocorticoid receptor (GR)α isoform. Recent data suggest that the mature GRα mRNA is translated into multiple N-terminal isoforms that have distinct biochemical properties and gene regulatory profiles. Interestingly, osteosarcoma cells stably expressing the GRα-D translational isoform are unique in that they are resistant to glucocorticoid-induced apoptosis. In this study, we investigate whether GRα isoform-specific differences in the regulation of antiapoptotic genes contribute to this resistant phenotype. We now show that GRα-D, unlike the other receptor isoforms, does not inhibit the activity of a nuclear factor κB (NF-κB)-responsive reporter gene and does not efficiently repress either the transcription or protein production of the antiapoptotic genes Bcl-xL, cellular inhibitor of apoptosis protein 1, and survivin. The inability of GRα-D to down-regulate the expression of these genes appears to be associated with a diminished interaction between GRα-D and NF-κB that is observed in cells, but not in vitro, and likely reflects the sequestration of GRα-D in the nucleus. Deletion of the GRα N-terminal amino acids 98-335 also results in a nuclear resident GR, which fails to interact with NF-κB in cells and promote apoptosis in response to glucocorticoids. These data suggest that the N-terminal translational isoforms of GRα selectively regulate antiapoptotic genes and that the GRα-D isoform may contribute to the resistance of certain cancer cells to glucocorticoid-induced apoptosis.

Changes in expression of membrane TNF, NF-{kappa}B activation and neutrophil apoptosis during active and resolved inflammation

BACKGROUND

Tumour necrosis factor (TNF) is central to the pathophysiological process of rheumatoid arthritis (RA), whether as soluble cytokine or membrane-expressed pro-TNF (mTNF).

OBJECTIVES

To determine whether neutrophils, which can express TNF, are activated in the blood of patients with RA compared with healthy controls. To investigate, by focusing on mTNF expression, if the functions of RA neutrophils change in response to therapeutic TNF inhibition.

METHODS

TNF was measured by flow cytometry and qPCR in neutrophils from 20 patients with RA before and after the start of TNF inhibitor therapy. Apoptosis was measured by morphology, and western blotting of pro- and antiapoptotic proteins in cell lysates. Nuclear factor κB (NF-κB) activation was determined by western blotting of phosphorylated NF-κB (p65).

RESULTS

Before treatment RA neutrophils exhibited increased TNF mRNA expression, elevated mTNF levels and NF-κB activity compared with controls. They also underwent delayed apoptosis as shown by altered expression of anti- and proapoptotic proteins, such as Mcl-1 and caspases. Neutrophil TNF expression returned to baseline levels during successful treatment with anti-TNF biological agents, and there was a close correlation between clinical disease improvement and changes in neutrophil function.

CONCLUSIONS

Neutrophils express elevated levels of TNF in RA and the transcription factor, NF-κB, a target of TNF, is activated. This mechanism could lead to a self-sustained inflammatory process. These data point to an important role of neutrophils in the abnormal TNF signalling pathways activated in RA and provide new evidence that neutrophils actively contribute to altered cytokine signalling in inflammatory diseases.

A novel pentamethoxyflavone down-regulates tumor cell survival and proliferative and angiogenic gene products through inhibition of IκB kinase activation and sensitizes tumor cells to apoptosis by cytokines and chemotherapeutic agents

Most anticancer drugs have their origin in traditional medicinal plants. We describe here a flavone, 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (PMF), from the leaves of the Thai plant Gardenia obtusifolia, that has anti-inflammatory and anticancer potential. Because the nuclear factor-κB (NF-κB) pathway is linked to inflammation and tumorigenesis, we investigated the effect of PMF on this pathway. We found that PMF suppressed NF-κB activation induced by inflammatory agents, tumor promoters, and carcinogens. This suppression was not specific to the cell type. Although PMF did not directly modify the ability of NF-κB proteins to bind to DNA, it inhibited IκBα (inhibitory subunit of NF-κB) kinase, leading to suppression of phosphorylation and degradation of IκBα, and suppressed consequent p65 nuclear translocation, thus abrogating NF-κB-dependent reporter gene expression. Suppression of the NF-κB cell signaling pathway by the flavone led to the inhibition of expression of NF-κB-regulated gene products that mediate inflammation (cyclooxygenase-2), survival (XIAP, survivin, Bcl-xL, and cFLIP), proliferation (cyclin D1), invasion (matrix metalloproteinase-9), and angiogenesis (vascular endothelial growth factor). Suppression of antiapoptotic gene products by PMF correlated with the enhancement of apoptosis induced by tumor necrosis factor-α and the chemotherapeutic agents cisplatin, paclitaxel, and 5-flurouracil. Overall, our results indicate that PMF suppresses the activation of NF-κB and NF-κB-regulated gene expression, leading to the enhancement of apoptosis. This is the first report to demonstrate that this novel flavone has anti-inflammatory and anticancer effects by targeting the IKK complex.

Basic concepts of inflammation and its role in carcinogenesis

While the normal inflammatory cascade is self-limiting and crucial for host protection against invading pathogens and in the repair of damaged tissue, a wealth of evidence suggests that chronic inflammation is the engine driving carcinogenesis. Over a period of almost 150 years the link between inflammation and cancer development has been well established. In this chapter we discuss the fundamental concepts and mechanisms behind normal inflammation as it pertains to wound healing. We further discuss the association of inflammation and its role in carcinogenesis, highlighting the different stages of cancer development, namely tumour initiation, promotion and progression. With both the innate and adaptive arms of the immune system being central to the inflammatory process, we examine the role of a number of immune effectors in contributing to the carcinogenic process. In addition, we highlight the influences of host genetics in altering cancer risk.

The role of chalcones in suppression of NF-κB-mediated inflammation and cancer

Although consumption of fruits, vegetables, spices, cereals and pulses has been associated with lower incidence of cancer and other chronic diseases, how these dietary agents and their active ingredients minimize these diseases, is not fully understood. Whether it is oranges, kawa, hops, water-lilly, locorice, wax apple or mulberry, they are all connected by a group of aromatic ketones, called chalcones (1,3-diaryl-2-propen-1-ones). Some of the most significant chalcones identified from these plants include flavokawin, butein, xanthoangelol, 4-hydroxyderricin, cardamonin, 2',4'-dihydroxychalcone, isoliquiritigenin, isosalipurposide, and naringenin chalcone. These chalcones have been linked with immunomodulation, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, anticancer, and antidiabetic activities. The current review, however, deals with the role of various chalcones in inflammation that controls both the immune system and tumorigenesis. Inflammatory pathways have been shown to mediate the survival, proliferation, invasion, angiogenesis and metastasis of tumors. How these chalcones modulate inflammatory pathways, tumorigenesis and immune system is the focus of this review.