NF-kappaB and IKK as therapeutic targets in cancer

Complex Systems Biology Approach in Connecting PI3K-Akt and NF-κB Pathways in Prostate Cancer

Phosphatidylinositol 3′-OH kinase (PI3K)-Akt and transcription factor NF-κB are important molecules involved in the regulation of cell proliferation, apoptosis, and oncogenesis. Both PI3K-Akt and Nuclear Factor-kappaB (NF-κB) are involved in the development and progression of prostate cancer, however, the crosstalk and molecules connecting these pathway remains unclear. A multilevel system representation of the PI3K-Akt and NF-κB pathways was constructed to determine which signaling components contribute to adaptive behavior and coordination. In silico experiments conducted using PI3K-Akt and NF-κB, mathematical models were modularized using biological functionality and were validated using a cell culture system. Our analysis demonstrates that a component representing the IκB kinase (IKK) complex can coordinate these two pathways. It is expected that interruption of this molecule could represent a potential therapeutic target for prostate cancer.

Anticancer activity and mechanism of bis-pyrimidine based dimetallic Ru(II)(η6-p-cymene) complex in human non-small cell lung cancer via p53-dependent pathway

Non-small cell lung cancer (NSCLC) is the most common cancer worldwide, which is related with poor prognosis and resistance to chemotherapy. Notably, ruthenium-based complexes have emerged as good alternative to the currently used platinum-based drugs for cancer therapy. In the present study, we synthesized a novel bis-pyrimidine based ligand 1,3-bis(2-methyl-6-(pyridin-2-yl)pyrimidin-4-yl)benzene (L) and used it in the synthesis of a dimetallic Ru(II) cymene complex [(Ru(η⁶-p-cymene)Cl)₂(1,3-bis(2-methyl-6-(pyridin-2-yl)pyrimidin-4-yl)benzene)] (L-Ru). We checked the stability of this complex in solution state in D₂O/DMSO‑d₆ mixture and found it to be highly stable under these conditions. We determined the anticancer activity and mechanism of action of L-Ru in human NSCLC A549 and A427 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and related biological analyses. These results revealed that L-Ru exerted a strong inhibitory effect on the cells proliferation,G0/G1-arrest, accompanied with upregulation of p53, p21, p15, cleaved Poly (ADP-ribose) polymerase (PARP) protein and downregulation of cell cycle markers. L-Ru inhibited cell migration and invasion. The mitochondria-mediated apoptosis of NSCLC induced by L-Ru was also observed followed by the increase of apoptosis regulator B-cell lymphoma 2 associated X (BAX), and activation of caspase-3/-9. The effects of L-Ru on the cell viability, Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells and Annexin V-positive cells apoptosis induction were remarkably attenuated. This complex induced DNA damage, cell cycle arrest and cell death via caspase-dependent apoptosis involving PARP activation and induction of p53-dependent pathway. These findings suggested that this ruthenium complex might be a potential effective chemotherapeutic agent in NSCLC therapy.

Prognostic values of inhibitory κB kinases mRNA expression in human gastric cancer

Background: Inhibitory κB kinases (IKKs) play a key role in modulating proinflammatory and growth stimulating signals through their regulation of the nuclear factor κB (NF-κB) cascade. Therefore, the level of expression of IKKs represents a viable prognostic predictor with regard to various pathological processes. The prognostic value of IKKs expression in gastric cancer remains unclear. Methods: We used the 'Kaplan-Meier plotter' (KM plotter) online database, to explore the predictive prognostic value of individual IKKs members' mRNA expression to overall survival (OS) in different clinical data including pathological staging, histology, and therapies employed. Results: Our results revealed that a higher mRNA expression of inhibitor of NF-κB kinase subunit α (IKKα) was correlated to better OS, whereas higher mRNA expression of IKKβ, inhibitor of NF-κB kinase subunit γ (IKKγ), inhibitor of NF-κB kinase subunit ε (IKKε), and suppressor of IKKε (SIKE) were generally correlated to unfavorable OS in gastric cancer. Increased mRNA expression of IKKε also showed better outcomes in stage IV gastric cancer. Further a correlation between elevated levels of mRNA expression of both IKKε and SIKE was found to have favorable OS in diffuse type gastric cancer. It was also revealed that high expression of SIKE had favorable OS when treated with other adjuvant therapies, while worse OS when treated only with 5FU therapy. Conclusion: Our results suggest that mRNA expression of individual IKKs and SIKE are associated with unique prognostic significance and may act as valuable prognostic biomarkers and potential targets for future therapeutic interventions in gastric cancer.

Baicalin inhibits breast cancer development via inhibiting IĸB kinase activation in vitro and in vivo

The aim of the present study was to investigate the effect and therapeutic potential of baicalin in breast cancer. Baicalin is used to treat inflammatory diseases. The effects of baicalin were assessed in breast cancer MCF-7 and MDA-MB‑231 cells, and human breast cancer xenograft mice. Cells were treated with 0, 20 or 30 µM baicalin for 48 h, while xenograft mice were treated with intraperitoneal injection of 0, 100 or 200 mg/kg baicalin for 30 days. The results demonstrated that treatment with baicalin dose-dependently suppressed breast cancer cell invasion, migration and proliferation, and also induced G1/S-phase cell cycle arrest in vitro and in vivo. Baicalin alleviated inflammation injury and inhibited the secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1β, thus suppressing nuclear factor (NF)-ĸB-p65 activation via inhibition of IĸB kinase. Investigation of the mechanism underlying baicalin activity indicated that it inhibited protein expression of NF-ĸB-p65, leading to NF-ĸB‑induced increased expression of CCND1, BCL2, BIRC2 and BIRC3, thus inhibiting cell proliferation, invasion and migration and suppressing anti-apoptotic factors in vitro and in vivo. In addition, baicalin did not affect non-tumorigenic normal breast epithelial cells. These results indicate that baicalin may exert therapeutic effects in breast cancer.

USP24 induces IL-6 in tumor-associated microenvironment by stabilizing p300 and β-TrCP and promotes cancer malignancy

We have previously demonstrated that USP24 is involved in cancer progression. Here, we found that USP24 expression is upregulated in M2 macrophages and lung cancer cells. Conditioned medium from USP24-knockdown M2 macrophages decreases the migratory and chemotactic activity of lung cancer cells and the angiogenic properties of human microvascular endothelial cell 1 (HMEC-1). IL-6 expression is significantly decreased in USP24-knockdown M2 macrophages and lung cancer cells, and IL-6-replenished conditioned medium restores the migratory, chemotactic and angiogenetic properties of the cells. USP24 stabilizes p300 and β-TrCP to increase the levels of histone-3 acetylation and NF-κB, and decreases the levels of DNMT1 and IκB, thereby increasing IL-6 transcription in M2 macrophages and lung cancer cells, results in cancer malignancy finally. IL-6 has previously been a target for cancer drug development. Here, we provide direct evidence to support that USP24 promotes IL-6 expression, which might be beneficial for cancer therapy.

USP24 has previously been reported to be involved in cancer progression. Here, the authors demonstrate that USP24 stabilizes p300 and β-TrCP to increase the levels of NF-κB and histone-3 acetylation, and decrease DNMT1 and IκB levels which promotes IL-6 expression in M2 macrophages and lung cancer cells.

Macrophages confer resistance to PI3K inhibitor GDC-0941 in breast cancer through the activation of NF-κB signaling

The PI3K pathway is one of the most dysregulated signaling pathways in epithelial cancers and has become an attractive therapeutic target under active preclinical and clinical development. However, recent clinical trial studies revealed that blockade of PI3K activity in advanced cancer often leads to the development of resistance and relapse of the diseases. Intense efforts have been made to elucidate resistance mechanisms and identify rational drug combinations with PI3K inhibitors in solid tumors. In the current study, we found that PI3K inhibition by GDC-0941 increased macrophage infiltration and induced the expression of macrophage-associated cytokines and chemokines in the mouse 4T1 breast tumor model. Using the in vitro co-culture system, we showed that the presence of macrophages led to the activation of NF-κB signaling in 4T1 tumor cells, rendering tumor cells resistant to PI3K inhibition by GDC-0941. Furthermore, we found that Aspirin could block the activation of NF-κB signaling induced by PI3K inhibition, and combined use of GDC-0941 and Aspirin resulted in attenuated cell growth and enhanced apoptosis of 4T1 cells in the in vitro co-culture system with the presence of macrophages. Consistently, the combination treatment also effectively reduced tumor burden, macrophage infiltration and pulmonary metastasis in in vivo 4T1 breast tumor model. Together, our results suggested macrophages in microenvironment may contribute to the resistance of breast cancer cells to PI3K inhibition and reveal a new combination paradigm to improve the efficacy of PI3K-targeted therapy.

Two new farnesyl phenolic compounds with anti-inflammatory activities from Ganoderma duripora

Ganoderma fungi have long been used as a famous traditional medicine and food in country of East Asia. In this work, two new farnesyl phenolic compounds, ganoduriporols A and B (1 and 2), were isolated from the fruiting bodies of Ganoderma duripora, and their structures were elucidated using various spectroscopic methods. Anti-inflammatory activities were assayed and evaluated for the two compounds. Ganoduriporols A and B exhibited dose-dependent anti-inflammatory effects in RAW 264.7 cells. Furthermore, ganoduriporol A was demonstrated to inhibit the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and prostaglandin E₂ (PGE₂) through the suppression of COX-2, MAPK and NF-κB signaling pathway in LPS-induced macrophage cells. These results suggested that these two new farnesyl phenolic compounds and the fruiting body of G. duripora could serve as anti-inflammatory agents for medicinal use or functional food.

Aqueous extract of Sapindus mukorossi induced cell death of A549 cells and exhibited antitumor property in vivo

Sapindus mukorossi is a deciduous plant and has recently been recognized to have anticancer property. In the present study, we discovered that S. mukorossi leaf and stem aqueous extract (SaM) contained two polysaccharides mainly made of myo-inositol, galactose, glucose, and fructose and the aim of this study was to investigate the antitumor property the aqueous extract SaM. In vitro treatment of SaM diminished proliferative potential of lung adenocarcinomic cells and induced intracellular oxidative stress, as well as necrotic cell death. Moreover, exposure to SaM attenuated cell migration, demonstrating the effectiveness at reducing invasive property of malignant lung cells. Gene and protein expression studies indicated that SaM treatment altered the expression of proliferation/survival modulator NF-κB, tumor growth modulator ERK2, metastasis-associated molecules MMP9/12, and tumor suppressor p53 in A549 cells. Using model animals bearing Lewis lung cancer cell LL/2, we demonstrated that SaM was antitumoral and did not induce any undesired organ damage, immunotoxicity, and off-target inflammation. This work, to our knowledge, is the first study documents the antitumor bioactivity of aqueous extract riched in polysaccharides from S. mukorossi and provides insights into the potential pharmacological application of SaM as antitumor agent against lung cancer.

Prediction of early hepatocellular carcinoma recurrence using germinal center kinase-like kinase

Germinal center kinase-like kinase (GLK) is a key controller of autoimmunity. In this study, we assessed the clinical relevance and tumorigenic effects of GLK in hepatocellular carcinoma (HCC). Using immunohistochemistry, we showed that the GLK proportion score increased in both cancerous and adjacent non-cancerous liver tissue from patients with HCC recurrence. A Kaplan-Meier analysis revealed that patients with a wide distribution of GLK in non-cancerous liver tissue had a higher rate of HCC recurrence than those with very low or no GLK expression. Multivariate Cox regression analyses indicated that a high GLK proportion score in non-cancerous liver tissue was an independent predictor of early HCC recurrence after resection. Lentiviral vector-mediated overexpression of GLK activated the nuclear factor kappa B (NFκB) signaling cascade and accelerated cell cycle progression in primary human hepatocytes, thereby promoting proliferation. An increase in GLK expression coincided with NFκB activation and enhanced expression of proliferating cell nuclear antigen in HCC tissue. Our findings demonstrate a potential hepatocarcinogenic effect of GLK and the feasibility of using GLK to predict early HCC recurrence.

Interplay between the NF‑κB and hedgehog signaling pathways predicts prognosis in esophageal squamous cell carcinoma following neoadjuvant chemoradiotherapy

Tumor recurrence and metastasis in esophageal squamous cell carcinoma (ESCC) are primary causes of patient mortality. The nuclear factor (NF)‑κB signaling pathway and hedgehog signaling pathway were previously reported to contribute to cell growth and metastasis in ESCC. The present study therefore investigated the roles of the NF‑κB and hedgehog pathways in ESCC tumors following neoadjuvant chemoradiotherapy (NCRT). By immunohistochemistry staining, it was observed that NF‑κB and glioma‑associated oncogene homolog 1 (Gli1), key components of the NF‑κB and hedgehog pathways, respectively, were decreased following NCRT, which was further confirmed by western blotting and reverse transcription‑quantitative polymerase chain reaction analysis. In addition, survival analysis suggested that high expression levels of either NF‑κB or Gli1 were associated with poor overall survival (OS) of patients. In the esophageal cell line TE‑8, NF‑κB and Gli1 formed a positive feedback loop, and inhibition of either NF‑κB or Gli1 may inhibit cell migration, invasion and proliferation. The results of the present study demonstrated that activation of the NF‑κB and hedgehog signaling pathways limited the OS of patients with ESCC following NCRT, and may therefore be suitable targets for ESCC treatment.

Schisandrol B and schisandrin B inhibit TGFβ1-mediated NF-κB activation via a Smad-independent mechanism

Aberrant transforming growth factor β1 (TGFβ1) signaling plays a pathogenic role in the development of vascular fibrosis. We have reported that Schisandra chinensis fruit extract (SCE), which has been used as a traditional oriental medicine, suppresses TGFβ1-mediated phenotypes in vascular smooth muscle cells (VSMCs). However, it is still largely unknown about the pharmacologic effects of SCE on various TGFβ1 signaling components. In this study, we found that SCE attenuated TGFβ1-induced NF-κB activation and nuclear translocation in VSMCs. Among the five active ingredients of SCE that were examined, schisandrol B (SolB) and schisandrin B (SchB) most potently suppressed TGFβ1-mediated NF-κB activation. In addition, SolB and SchB effectively inhibited IKKα/β activation and IκBα phosphorylation in TGFβ1-treated VSMCs. The pharmacologic effects of SolB and SchB on NF-κB activation were independent of the Smad-mediated canonical pathway. Therefore, our study demonstrates that SCE and its active constituents SolB and SchB suppress TGFβ1-mediated NF-κB signaling pathway in a Smad-independent mechanism. Our results may help further investigations to develop novel multi-targeted therapeutic strategies that treat or prevent vascular fibrotic diseases.

Mechanism of anticancer action of novel berenil complex of platinum(II) combined with anti-MUC1 in MCF-7 breast cancer cells

Mucin 1 (MUC1) is a high molecular weight transmembrane glycoprotein, that is overexpressed in >90% of breast cancers. It serves a crucial role in anti-apoptosis and tumor progression. MUC1 interacts with proteins in the extracellular matrix, at the cell membrane, in the cytoplasm and in the nucleus. The aim of the present study was to investigate the mechanism of anticancer action induced by novel berenil complex of platinum(II) (Pt12) together with a monoclonal antibody against MUC1 in breast cancer MCF-7 cells. The effect of combined treatment on the concentration of selected markers of apoptosis including proapoptotic B-cell lymphoma 2 associated X protein (Bax), caspase-8, cytochrome c and caspase-9, as well as selected proteins involved in intracellular signal transduction pathways including p53, phosphoinositide 3-kinase and phosphorylated protein kinase B (p-Akt) were analyzed. The results of the present study demonstrated that combined treatment may be a promising strategy in anticancer treatment and represents an alternative to monotherapy. All compounds used alone (Pt12, cisplatin and the anti-MUC1 antibody) increased the concentration of proapoptotic Bax, cytochrome c and caspase-9 in comparison with control, thus suggesting that they activated the mitochondrial apoptotic pathway. Pt12 alone significantly increased the concentration of caspase-8, which is responsible for the initiation of the extrinsic apoptotic pathway. However, the strongest effect was observed following Pt12 (20 µM) treatment combined with the anti-MUC1 antibody (10 µg/ml). These two compounds together strongly induced apoptosis in MCF-7 breast cancer cells via the external and internal apoptotic pathways. It was also demonstrated that combined treatment based on Pt12 and the anti-MUC1 antibody significantly reduced p-Akt concentration.

DMAPT inhibits NF-κB activity and increases sensitivity of prostate cancer cells to X-rays in vitro and in tumor xenografts in vivo

Constitutive activation of the pro-survival transcription factor NF-κB has been associated with resistance to both chemotherapy and radiation therapy in many human cancers, including prostate cancer. Our lab and others have demonstrated that the natural product parthenolide can inhibit NF-κB activity and sensitize PC-3 prostate cancers cells to X-rays in vitro; however, parthenolide has poor bioavailability in vivo and therefore has little clinical utility in this regard. We show here that treatment of PC-3 and DU145 human prostate cancer cells with dimethylaminoparthenolide (DMAPT), a parthenolide derivative with increased bioavailability, inhibits constitutive and radiation-induced NF-κB binding activity and slows prostate cancer cell growth. We also show that DMAPT increases single and fractionated X-ray-induced killing of prostate cancer cells through inhibition of DNA double strand break repair and also that DMAPT-induced radiosensitization is, at least partially, dependent upon the alteration of intracellular thiol reduction-oxidation chemistry. Finally, we demonstrate that the treatment of PC-3 prostate tumor xenografts with oral DMAPT in addition to radiation therapy significantly decreases tumor growth and results in significantly smaller tumor volumes compared to xenografts treated with either DMAPT or radiation therapy alone, suggesting that DMAPT might have a potential clinical role as a radiosensitizing agent in the treatment of prostate cancer.

Galectin-1 promotes tumor progression via NF-κB signaling pathway in epithelial ovarian cancer

Purpose: We previously reported that Galectin-1 (Gal-1) played a role in epithelial ovarian cancer (EOC) progression. In this study, we aimed to further investigate the association between Gal-1 expression and prognosis in EOC patients and tried to reveal some novel potential mechanisms of Gal-1 in EOC invasion and migration.

Materials and Methods: Gal-1 and nucleus NF-κBp65 expression in 109 human epithelial ovarian cancer tissue specimens were evaluated by immunohistochemistry. The Cox model and survival curves were used to investigate the effect of Gal-1 on EOC prognosis. Correlation between Gal-1 expression and NF-κB activation in EOC patients was also analyzed. In vitro experiments were further performed to reveal the function and mechanisms of Gal-1 in invasion and migration of EOC cells.

Results: Expression level of Gal-1 in EOC tissue was an independent prognostic factor on overall survival (p<0.05) and progression-free survival (p<0.05). Patients with high Galectin-1 expression had shorter overall survival (OS, p<0.05)) and progression-free survival (PFS, p<0.05). Immunohistochemistry revealed that expression of Gal-1 was positively associated with activation of NF-κBp65 in EOC tissues (Kappa coefficient=0.458, p<0.001). Patients with tumors concomitantly co-over-expressing Gal-1 and NF-κBp65 had the worse OS (p<0.001) and PFS (p<0.001). The abilities of migration and invasion for EOC cells were significantly reduced after Gal-1 knocked-down in human EOC cell line HO8910, which was accompanied with the suppression of NF-κb pathway activation and with the matrix metalloproteinase-2 and matrix metalloproteinase-9 down-regulation.

Conclusions: Our results suggest that Gal-1 is associated with poor outcome in EOC and Galectin-1 promotes tumor progression via NF-κB pathway activation in EOC.

NF-κB c-Rel Is Crucial for the Regulatory T Cell Immune Checkpoint in Cancer

Regulatory T cells (Tregs) play a pivotal role in the inhibition of anti-tumor immune responses. Understanding the mechanisms governing Treg homeostasis may therefore be important for development of effective tumor immunotherapy. We have recently demonstrated a key role for the canonical nuclear factor κB (NF-κB) subunits, p65 and c-Rel, in Treg identity and function. In this report, we show that NF-κB c-Rel ablation specifically impairs the generation and maintenance of the activated Treg (aTreg) subset, which is known to be enriched at sites of tumors. Using mouse models, we demonstrate that melanoma growth is drastically reduced in mice lacking c-Rel, but not p65, in Tregs. Moreover, chemical inhibition of c-Rel function delayed melanoma growth by impairing aTreg-mediated immunosuppression and potentiated the effects of anti-PD-1 immunotherapy. Our studies therefore establish inhibition of NF-κB c-Rel as a viable therapeutic approach for enhancing checkpoint-targeting immunotherapy protocols.

Pyrrolidine dithiocarbamate sensitizes U251 brain glioma cells to temozolomide via downregulation of MGMT and BCL-XL

The current study investigated the effect of pyrrolidine dithiocarbamate (PDTC) on the proliferation, apoptosis, cell cycle and sensitivity to temozolomide (TMZ) of the U251 glioma cell line. Proliferation, apoptosis and cell cycle analysis of U251 cells following treatment with PDTC and TMZ was determined by an MTT assay and flow cytometry, respectively. The mRNA and protein expression levels of O-6-methylguanine-DNA methyltransferase (MGMT), B-cell lymphoma extra-large (BCL-XL) and survivin were further determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting analysis. The results revealed that treatment with TMZ, PDTC and TMZ + PDTC significantly inhibited cell proliferation, induced apoptosis and contributed to cell cycle arrest in U251 cells. A combination of PDTC and TMZ induced the highest rates of proliferation inhibition and apoptosis. PDTC treatment markedly reduced the expression levels of MGMT, BCL-XL and survivin. The expression levels of MGMT and BCL-XL, were significantly upregulated by TMZ but not by combination treatment of TMZ and PDTC. The results of the present study suggest that treatment with PDTC inhibits cell proliferation, induces apoptosis and cell cycle arrest, and enhances sensitivity to TMZ in U251 cells, which is partly induced by downregulation of MGMT and BCL-XL.

Upregulation of ASAP3 contributes to colorectal carcinogenesis and indicates poor survival outcome

The function and clinical implication of ArfGAP with SH3 domain, ankyrin repeat, and PH domain 3 (ASAP3) in colorectal cancer (CRC) remains undefined. In the present study, we showed that the expression level of ASAP3 was dramatically increased in CRC and its upregulation was associated with American Joint Committee on Cancer stage (P < 0.001) and poor prognosis (P = 0.0022). The combination of stage and ASAP3 expression improved the prediction of survival in CRC patients. Suppression of ASAP3 inhibited cell proliferation by inducing G1 phase arrest without influencing apoptosis. ASAP3 promoted growth of colon tumors in mice with colitis, and accelerated cell invasion and migration in vitro. Increased ASAP3 was associated with activation of the nuclear factor-κB (NF-κB) canonical pathway in CRC. Upregulation of ASAP3 increased the phosphorylation and nuclear translocation of the p65 NF-κB subunit. Mechanistically, ASAP3 interacts with NF-κB essential modulator (NEMO) and could reduce the polyubiquitinylation of NEMO. Overall, ASAP3 might regulate NF-κB via binding to NEMO. ASAP3 acts as an oncogene in colonic cancer and could be a potential biomarker of colon carcinogenesis.

Hypoxia and Inflammation in Cancer, Focus on HIF and NF-κB

Cancer is often characterised by the presence of hypoxia and inflammation. Paramount to the mechanisms controlling cellular responses under such stress stimuli, are the transcription factor families of Hypoxia Inducible Factor (HIF) and Nuclear Factor of κ-light-chain-enhancer of activated B cells (NF-κB). Although, a detailed understating of how these transcription factors respond to their cognate stimulus is well established, it is now appreciated that HIF and NF-κB undergo extensive crosstalk, in particular in pathological situations such as cancer. Here, we focus on the current knowledge on how HIF is activated by inflammation and how NF-κB is modulated by hypoxia. We summarise the evidence for the possible mechanism behind this activation and how HIF and NF-κB function impacts cancer, focusing on colorectal, breast and lung cancer. We discuss possible new points of therapeutic intervention aiming to harness the current understanding of the HIF-NF-κB crosstalk.

Reactive oxygen species modulator-1 (Romo1) predicts unfavorable prognosis in colorectal cancer patients

Background

Reactive oxygen species modulator-1 (Romo1) is a novel protein that has been reported to be crucial for cancer cell proliferation and invasion. However, its clinical implications in colorectal cancer patients are not well-known. For the first time, we investigated the association between Romo1 and the clinical outcomes of colorectal cancer patients.

Study

We examined Romo1 expression in resected tumor tissues immunohistochemically and assessed it with histological scores. We conducted survival analyses for patients who had curative resection (n = 190) in accordance with clinical parameters including level of Romo1 expression, and we examined the association between Romo1 expression and cell invasion using Matrigel invasion assay in colorectal cancer cells.

Results

We observed significantly longer mean disease-free survival in the low Romo1 group compared with the high Romo1 group (161 vs 127.6 months, p = 0.035), and the median overall survival of the low Romo1 group was significantly longer than that of the high Romo1 group (196.9 vs 171.3 months, p = 0.036). Cell invasiveness decreased in the Romo1 knockdown colorectal cancer cells in contrast to the controlled cells. Romo1 overexpression in tumor tissue was associated with a high lymph node ratio between the metastatic and examined lymph nodes (p = 0.025).

Conclusions

Romo1 overexpression in tumor tissue was significantly associated with survival in curatively resected colorectal cancer patients, suggesting Romo1 expression as a potential adverse prognostic marker. Increased Romo1 expression was found to be associated with high lymph node ratio. Cancer invasiveness appeared to be a key reason for the poor survival related to highly expressed Romo1.

Immunomodulatory glc/man-directed Dolichos lablab lectin (DLL) evokes anti-tumour response in vivo by counteracting angiogenic gene expressions

Neovascularization and jeopardized immunity has been critically emphasized for the establishment of malignant progression. Lectins are the diverse class of carbohydrate interacting proteins, having great potential as immunopotentiating and anti-cancer agents. The present investigation sought to demonstrate the anti-proliferative activity of Dolichos lablab lectin (DLL) encompassing immunomodulatory attributes. DLL specific to glucose and mannose carbohydrate moieties has been purified to homogeneity from the common dietary legume D. lablab. Results elucidated that DLL agglutinated blood cells non-specifically and displayed striking mitogenicity to human and murine lymphocytes in vitro with interleukin (IL)-2 production. The DLL-conditioned medium exerted cytotoxicity towards malignant cells and neoangiogenesis in vitro. Similarly, in-vivo anti-tumour investigation of DLL elucidated the regressed proliferation of ascitic and solid tumour cells, which was paralleled with blockade of tumour neovasculature. DLL-treated mice showed an up-regulated immunoregulatory cytokine IL-2 in contrast to severely declined levels in control mice. Mechanistic validation revealed that DLL has abrogated the microvessel formation by weakening the proangiogenic signals, specifically nuclear factor kappa B (NF-κB), hypoxia inducible factor 1α (HIF-1 α), matrix metalloproteinase (MMP)-2 and 9 and vascular endothelial growth factor (VEGF) in malignant cells leading to tumour regression. In summary, it is evident that the dietary lectin DLL potentially dampens the malignant establishment by mitigating neoangiogenesis and immune shutdown. For the first time, to our knowledge, this study illustrates the critical role of DLL as an immunostimulatory and anti-angiogenic molecule in cancer therapeutics.

DNA damage-induced nuclear factor-kappa B activation and its roles in cancer progression

DNA damage is a vital challenge to cell homeostasis. Cellular responses to DNA damage (DDR) play essential roles in maintaining genomic stability and survival, whose failure could lead to detrimental consequences such as cancer development and aging. Nuclear factor-kappa B (NF-κB) is a family of transcription factors that plays critical roles in cellular stress response. Along with p53, NF-κB modulates transactivation of a large number of genes which participate in various cellular processes involved in DDR. Here the authors summarize the recent progress in understanding DNA damage response and NF-κB signaling pathways. This study particularly focuses on DNA damage-induced NF-κB signaling cascade and its physiological and pathological significance in B cell development and cancer therapeutic resistance. The authors also discuss promising strategies for selectively targeting this genotoxic NF-κB signaling aiming to antagonize acquired resistance and resensitize refractory cancer cells to cytotoxic treatments.

Helicteric Acid, Oleanic Acid, and Betulinic Acid, Three Triterpenes from Helicteres angustifolia L., Inhibit Proliferation and Induce Apoptosis in HT-29 Colorectal Cancer Cells via Suppressing NF-κB and STAT3 Signaling

Colorectal cancer (CRC) is one of the most common malignancies and most frequent cause of cancer death worldwide. The activation of both NF-κB and STAT3 signaling and the crosstalk between them play an important role in colorectal tumor. Helicteres angustifolia L. is a type of commonly used Chinese medicinal herb and possesses a wide variety of biological activities. In the present study, we investigate the effects of three triterpenes from H. angustifolia (HT) such as helicteric acid (HA), oleanic acid (OA), and betulinic acid (BA), on inhibiting CRC progression. Our results showed that HT extracts could decrease proliferation and induce apoptosis in HT-29 colorectal cancer cells. Moreover, HT extracts could suppress LPS-triggered phosphorylation of IKK, IκB, and NF-κB, attenuate IL-6-induced phosphorylation of JAK2 and STAT3, and suppress the expression of c-Myc, cyclin-D1, and BCL-xL, the downstream gene targets of NF-κB and STAT3. Therefore, HT extracts showed potent therapeutic and antitumor effects on CRC via inhibiting NF-κB and STAT3 signaling.

30 Years of NF-κB: A Blossoming of Relevance to Human Pathobiology

NF-κB was discovered 30 years ago as a rapidly inducible transcription factor. Since that time, it has been found to have a broad role in gene induction in diverse cellular responses, particularly throughout the immune system. Here, we summarize elaborate regulatory pathways involving this transcription factor and use recent discoveries in human genetic diseases to place specific proteins within their relevant medical and biological contexts.

Potential applications of nanoparticles in cancer immunotherapy

In recent years considerable progress has been made in the field of cancer immunotherapy whereby treatments that modulate the body's own immune system are used to combat cancer. This has the potential to not only elicit strong anti-cancer immune responses which can break pre-existing tolerance and help promote tumor regression, but could also induce immunological memory which may help prevent tumor recurrence. In order to ensure effective delivery of immunotherapeutic agents, such as vaccines, checkpoint inhibitors, chemotherapeutic agents and nucleic acids, a safe and effective delivery system is often required. One such approach is the use of multifunctional nanoparticles (NPs), such as liposomes, polymers, micelles, dendrimers, inorganic NPs, and hybrid NPs, which have the potential to combine the delivery of a diverse range of therapeutic immunomodulators thereby increasing the efficacy of tumor cell killing. This review focuses on recent progress in NP-mediated immunotherapy for the treatment of cancer.

Inhibition of IKK-NFκB pathway sensitizes lung cancer cell lines to radiation

Objective

: Cancer cell radioresistance is a stumbling block in radiation therapy. The activity in the nuclear factor kappa B (NFκB) pathway correlates with anti-apoptotic mechanisms and increased radioresistance. The IKK complex plays a major role in NFκB activation upon numerous signals. In this study, we examined the interaction between ionizing radiation (IR) and different members of the IKK-NFκB pathway, as well as upstream activators, RAF1, ERK, and AKT1.

Methods

: The effect of 4 Gy of IR on the expression of the RAF1-ERK-IKK-NFκB pathway was examined in A549 and H1299 lung cancer cell lines using Western blot analysis and confocal microscopy. We examined changes in radiation sensitivity using gene silencing or pharmacological inhibitors of ERK and IKKβ.

Results

: IKKα, IKKγ, and IκBα increased upon exposure to IR, thereby affecting nuclear levels of NFκB (phospho-p65). ERK inhibition or siRNA-mediated down-regulation of RAF1 suppressed the post-irradiation survival of the examined lung cancer cell lines. A similar effect was detected on survival upon silencing IKKα/IKKγ or inhibiting IKKβ.

Conclusions

: Exposure of lung cancer cells to IR results in NFκB activation via IKK. The genetic or pharmacological blockage of the RAF1-ERK-IKK-NFκB pathway sensitizes cells to therapeutic doses of radiation. Therefore, the IKK pathway is a promising target for therapeutic intervention in combination with radiotherapy.

Inhibition of Allergic Response by Intranasal Selective NF-κB Decoy Oligodeoxynucleotides in a Murine Model of Allergic Rhinitis

Purpose

It remains unknown whether local inhibition of Nuclear factor-kappa B (NF-κB) could have therapeutic value in the treatment of allergic rhinitis (AR). This study aimed to evaluate the effect of selective NF-κB inhibition using NF-κB decoy oligodeoxynucleotides (ODNs) for the local treatment of AR in ovalbumin (OVA)-sensitized wild-type mice.

Methods

BALB/c mice were sensitized with OVA and alum, and then challenged intranasally with OVA. NF-κB decoy ODNs were given intranasally to the treatment group, and NF-κB scrambled ODNs were given to the sham treatment group. Allergic symptom scores, eosinophil infiltration, cytokine levels in the nasal mucosa, nasal lavage fluid, and spleen cell culture, serum total and OVA-specific immunoglobulins, as well as intercellular adhesion molecure-1 (ICAM-1) in the nasal mucosa, were analyzed.

Results

NF-κB decoy ODNs significantly reduced allergic symptoms and eosinophil infiltration in the nasal mucosa. They also suppressed serum levels of total IgE, OVA-specific IgE, and IgG1. IL-5 and TNF-α levels and the expression of ICAM-1 were decreased in the nasal mucosa of the treatment group compared to the positive control and sham treatment groups. In addition, IL-6 levels were significantly decreased in the nasal lavage fluid of the treatment group. Furthermore, NF-κB decoy ODNs significantly reduced expression of the systemic Th2 cytokines, IL-4 and IL-5 in spleen cell culture.

Conclusions

This study demonstrates for the first time that local NF-κB inhibition using NF-κB decoy ODNs suppressed the allergic response in a murine AR model. This shows the therapeutic potential of local NF-κB inhibition in the control of AR.

RelA NF-κB subunit activation as a therapeutic target in diffuse large B-cell lymphoma

It has been well established that nuclear factor kappa-B (NF-κB) activation is important for tumor cell growth and survival. RelA/p65 and p50 are the most common NF-kB subunits and involved in the classical NF-kB pathway. However, the prognostic and biological significance of RelA/p65 is equivocal in the field. In this study, we assessed RelA/p65 nuclear expression by immunohistochemistry in 487 patients with de novo diffuse large B-cell lymphoma (DLBCL), and studied the effects of molecular and pharmacological inhibition of NF-kB on cell viability. We found RelA/p65 nuclear expression, without associations with other apparent genetic or phenotypic abnormalities, had unfavorable prognostic impact in patients with stage I/II DLBCL. Gene expression profiling analysis suggested immune dysregulation and antiapoptosis may be relevant for the poorer prognosis associated with p65 hyperactivation in germinal center B-cell-like (GCB) DLBCL and in activated B-cell-like (ABC) DLBCL, respectively. We knocked down individual NF-κB subunits in representative DLBCL cells in vitro, and found targeting p65 was more effective than targeting other NF-κB subunits in inhibiting cell growth and survival. In summary, RelA/p65 nuclear overexpression correlates with significant poor survival in early-stage DLBCL patients, and therapeutic targeting RelA/p65 is effective in inhibiting proliferation and survival of DLBCL with NF-κB hyperactivation.

Enhancement of adoptive T cell transfer with single low dose pretreatment of doxorubicin or paclitaxel in mice

Ex vivo expansion of CD8+ T-cells has been a hindrance for the success of adoptive T cell transfer in clinic. Currently, preconditioning with chemotherapy is used to modulate the patient immunity before ACT, however, the tumor microenvironment beneficial for transferring T cells may also be damaged. Here preconditioning with single low dose of doxorubicin or paclitaxel combined with fewer CD8+ T-cells was investigated to verify whether the same therapeutic efficacy of ACT could be achieved. An E.G7/OT1 animal model that involved adoptive transfer of OVA-specific CD8+ T-cells transduced with a granzyme B promoter-driven firefly luciferase and tomato fluorescent fusion reporter gene was used to evaluate this strategy. The result showed that CD8+ T-cells were activated and sustained longer in mice pretreated with one low-dose Dox or Tax. Enhanced therapeutic efficacy was found in Dox or Tax combined with 2x106 CD8+ T-cells and achieved the same level of tumor growth inhibition as that of 5x106 CD8+ T-cells group. Notably, reduced numbers of Tregs and myeloid derived suppressor cells were shown in combination groups. By contrast, the number of tumor-infiltrating cytotoxic T lymphocytes and IL-12 were increased. The NF-κB activity and immunosuppressive factors such as TGF-β, IDO, CCL2, VEGF, CCL22, COX-2 and IL-10 were suppressed. This study demonstrates that preconditioning with single low dose Dox or Tax and combined with two fifth of the original CD8+ T-cells could improve the tumor microenvironment via suppression of NF-κB and its related immunosuppressors, and activate more CD8+ T-cells which also stay longer.

Anticancer effect of SZC015 on lung cancer cells through ROS-dependent apoptosis and autophagy induction mechanisms in vitro

Oleanolic acid (OA) and its several derivatives possess various pharmacological activities, such as antitumor and anti-inflammation. In present study, anticancer effect of SZC015, an OA derivative, and its underlying mechanisms were investigated. We demonstrated that cell viability was significantly decreased in SZC015-treated lung cancer cells, but has less cytotoxicity in human bronchial epithelial cell line. Further investigation verified that apoptosis and autophagy induction and G0/G1 phase arrest were observed in SZC015-treated H322 cells. Mechanically, the level of Akt, p-Akt, p-IκBα, and total p65, the p-p65 in the cytoplasm and nucleus were suppressed by SZC015 in H322 cells, respectively. Inhibition of p65 nuclear translocation was also confirmed by immunofluorescence staining. In addition, co-treatment with chloroquine, an autophagy inhibitor, significantly inhibited SZC015-induced autophagy and enhanced SZC015-induced apoptotic cell death. Intracellular ROS was increased in a concentration-dependent manner, which could be prevented by N-Acetyl l-Cysteine, an ROS scavenger. Moreover, the level of Akt and procaspase-3 were increased, while the ratio of LC3 II/I was decreased. Taken together, our study demonstrates that the inhibitory effect of SZC015 against H322 cells is mediated by excessive ROS generation that could suppress Akt/NF-κB signaling pathway, which thereby leads to apoptotic and autophagic cell death.

UBXD Proteins: A Family of Proteins with Diverse Functions in Cancer

The UBXD family is a diverse group of UBX (ubiquitin-regulatory X) domain-containing proteins in mammalian cells. Members of this family contain a UBX domain typically located at the carboxyl-terminal of the protein. In contrast to the UBX domain shared by all members of UBXD family, the amino-terminal domains are diverse and appear to carry out different roles in a subcellular localization-dependent manner. UBXD proteins are principally associated with the endoplasmic reticulum (ER), where they positively or negatively regulate the ER-associated degradation machinery (ERAD). The distinct protein interaction networks of UBXD proteins allow them to have specific functions independent of the ERAD pathway in a cell type- and tissue context-dependent manner. Recent reports have illustrated that a number of mammalian members of the UBXD family play critical roles in several proliferation and apoptosis pathways dysregulated in selected types of cancer. This review covers recent advances that elucidate the therapeutic potential of selected members of the UBXD family that can contribute to tumor growth.

Evaluation of neutrophil-to-lymphocyte ratio as a potential biomarker for acute cholecystitis

BACKGROUND

The diagnosis of acute cholecystitis (AC) is frequently associated with an increase in white cell count (WCC) and C-reactive protein (CRP). However, one or both of these inflammatory biomarkers can be normal in AC. The aim of this study was to evaluate and compare the discriminative powers of the neutrophil-to-lymphocyte ratio (NLR) with WCC and CRP in diagnosing AC.

METHODS

This was a retrospective cohort study. For more than a period of 5 y, 1959 patients were identified from the cholecystectomy Registry. Laparoscopic cholecystectomy patients with histologic evidence of AC were included if they also had preoperative WCC and CRP measurements. Eligibility criteria were met by 177 patients. These patients were compared with 45 control subjects who had normal gallbladder histology.

RESULTS

One unit of increase in the NLR was associated with a 2.5 times increase in the odds of AC (odds ratio = 2.48; 95% confidence interval [CI], 1.5-4.1; P < 0.0005). NLR cutoff values of 4.1 (95% CI, 3.42-4.79), 3.25 (95% CI, 1.95-4.54), and 4.17 (95% CI, 3.76-4.58) were diagnostic for the overall AC, mild, and moderate-severe AC, respectively. The NLR areas under the receiver operating characteristic curve in AC, mild, and moderate-severe AC were 94% (95% CI, 91%-97%), 87% (95% CI, 81%-93%), and 98% (95% CI, 96%-100%), respectively. The discriminative power of an NLR was superior to that of the WCC and similar to CRP for diagnosing AC and different grades of severity.

CONCLUSIONS

NLR can be considered as a potential inflammatory biomarker for AC.

A RelA(p65) Thr505 phospho-site mutation reveals an important mechanism regulating NF-κB-dependent liver regeneration and cancer

Post-translational modifications of nuclear factor (NF)-κB subunits provide a mechanism to differentially regulate their activity in response to the many stimuli that induce this pathway. However, the physiological significance of these modifications is largely unknown, and it remains unclear if these have a critical role in the normal and pathological functions of NF-κB in vivo. Among these, phosphorylation of the RelA(p65) Thr505 residue has been described as an important regulator of NF-κB activity in cell lines, but its physiological significance was not known. Therefore, to learn more about the role of this pathway in vivo, we generated a knockin mouse with a RelA T505A mutation. Unlike RelA knockout mice, the RelA T505A mice develop normally but exhibit aberrant hepatocyte proliferation following liver partial hepatectomy or damage resulting from carbon tetrachloride (CCl4) treatment. Consistent with these effects, RelA T505A mice exhibit earlier onset of cancer in the N-nitrosodiethylamine model of hepatocellular carcinoma. These data reveal a critical pathway controlling NF-κB function in the liver that acts to suppress the tumour-promoting activities of RelA.

Cigarette smoke extract induces the proliferation of normal human urothelial cells through the NF-κB pathway

Bladder cancer is a common genitourinary malignant disease worldwide. Convincing evidence shows that cigarette smoke (CS) is a crucial risk factor for bladder cancer, yet the role of the NF-κB signaling pathway in the development of CS-associated bladder cancer has not been fully elucidated. In the present study, we found that exposure to cigarette smoke extract (CSE) induced proliferation and triggered the transition of normal human urothelial cells from G1 to S phase. Moreover, CSE exposure enhanced the expression of cyclin D1 and proliferating cell nuclear antigen (PCNA) and decreased the expression of p21 in SV-HUC-1 cells. Furthermore, the levels of nuclear NF-κB p65/p50 were significantly elevated by CSE. Pre-treatment with the NF-κB inhibitor (PDTC) reversed CSE-triggered cell proliferation. Taken together, our study revealed that CSE induced proliferation of normal human urothelial cells through the NF-κB pathway, and these data enhance our understanding of the CSE-related carcinogenesis of bladder cancer.

Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-κB signalling pathway

Resistance to oxaliplatin (OXA) is a complex process affecting the outcomes of metastatic colorectal cancer (CRC) patients treated with this drug. De-regulation of the NF-κB signalling pathway has been proposed as an important mechanism involved in this phenomenon. Here, we show that NF-κB was hyperactivated in in vitro models of OXA-acquired resistance but was attenuated by the addition of Curcumin, a non-toxic NF-κB inhibitor. The concomitant combination of Curcumin + OXA was more effective and synergistic in cell lines with acquired resistance to OXA, leading to the reversion of their resistant phenotype, through the inhibition of the NF-κB signalling cascade. Transcriptomic profiling revealed the up-regulation of three NF-κB-regulated CXC-chemokines, CXCL8, CXCL1 and CXCL2, in the resistant cells that were more efficiently down-regulated after OXA + Curcumin treatment as compared to the sensitive cells. Moreover, CXCL8 and CXCL1 gene silencing made resistant cells more sensitive to OXA through the inhibition of the Akt/NF-κB pathway. High expression of CXCL1 in FFPE samples from explant cultures of CRC patients-derived liver metastases was associated with response to OXA + Curcumin. In conclusion, we suggest that combination of OXA + Curcumin could be an effective treatment, for which CXCL1 could be used as a predictive marker, in CRC patients.

Bufalin Inhibits NCI-H460 Human Lung Cancer Cell Metastasis In Vitro by Inhibiting MAPKs, MMPs, and NF-κB Pathways

Bufalin, a component of Chan Su (a traditional Chinese medicine), has been known to have antitumor effects for thousands of years. In this study, we investigated its anti-metastasis effects on NCI-H460 lung cancer cells. Under sub-lethal concentrations (from 25 up to 100 nM), bufalin significantly inhibits the invasion and migration nature of NCI-H460 cells that were measured by Matrigel Cell Migration Assay and Invasion System. Bufalin also suppressed the enzymatic activity of matrix metalloproteinase (MMP)-9, which was examined by gelatin zymography methods. Western blotting revealed that bufalin depressed several key metastasis-related proteins, such as NF-κB, MMP-2, MMP-9, protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3-K), phosphorylated Akt, growth factor receptor-bound protein 2 (GRB2), phosphorylated extracellular signal-regulated kinase (ERK), phosphorylated p38, and phosphorylated c-Jun NH2-terminal kinase (JNK). As evidenced by immunostaining and the electrophoretic mobility shift assay (EMSA), bufalin induced not only a decreased cytoplasmic NF-κB production, but also decreased its nuclear translocation. Several metastasis-related genes, including Rho-associated (Rho A), coiled-coil-containing protein kinase 1 (ROCK1), and focal adhesion kinase (FAK), were down-regulated after bufalin treatment. In conclusion, bufalin is effective in inhibiting the metastatic nature of NCI-H460 cells in low, sub-lethal concentrations. Such an effect involves many mechanisms including MMPs, mitogen-activated protein kinases (MAPKs) and NF-κB systems. Bufalin has a potential to evolve into an anti-metastasis drug for human lung cancer in the future.

Targeting IκB Kinase β/NF-κB Signaling in Human Prostate Cancer by a Novel IκB Kinase β Inhibitor CmpdA

NF-κB plays an important role in many types of cancer, including prostate cancer, but the role of the upstream kinase of NF-κB, IKKβ, in prostate cancer has neither been fully documented nor are there any effective IKKβ inhibitors used in clinical settings. Here, we have shown that IKKβ activity is mediated by multiple kinases including IKKα in human prostate cancer cell lines that express activated IKKβ. IHC analysis (IHC) of human prostate cancer tissue microarrays (TMA) demonstrates that phosphorylation of IKKα/β within its activation loop gradually increases in low to higher stage tumors as compared with normal tissue. The expression of cell proliferation and survival markers (Ki-67, Survivin) and epithelial-to-mesenchymal transition (EMT) markers (Slug, Snail), as well as cancer stem cell (CSC)-related transcription factors (Nanog, Sox2, Oct-4), also increase in parallel among the respective TMA samples analyzed. IKKβ, but not NF-κB, is found to regulate Nanog, which, in turn, modulates the levels of Oct4, Sox2, Snail, and Slug, indicating an essential role of IKKβ in regulating CSCs and EMT. The novel IKKβ inhibitor CmpdA inhibits constitutively activated IKKβ/NF-κB signaling, leading to induction of apoptosis and inhibition of proliferation, migration, and stemness in these cells. CmpdA also significantly inhibits tumor growth in xenografts without causing apparent in vivo toxicity. Furthermore, CmpdA and docetaxel act synergistically to inhibit proliferation of prostate cancer cells. These results indicate that IKKβ plays a pivotal role in prostate cancer, and targeting IKKβ, including in combination with docetaxel, may be a potentially useful strategy for treating advanced prostate cancer. Mol Cancer Ther; 15(7); 1504-14. ©2016 AACR.

Transcription Factors in the Cellular Response to Charged Particle Exposure

Charged particles, such as carbon ions, bear the promise of a more effective cancer therapy. In human spaceflight, exposure to charged particles represents an important risk factor for chronic and late effects such as cancer. Biological effects elicited by charged particle exposure depend on their characteristics, e.g., on linear energy transfer (LET). For diverse outcomes (cell death, mutation, transformation, and cell-cycle arrest), an LET dependency of the effect size was observed. These outcomes result from activation of a complex network of signaling pathways in the DNA damage response, which result in cell-protective (DNA repair and cell-cycle arrest) or cell-destructive (cell death) reactions. Triggering of these pathways converges among others in the activation of transcription factors, such as p53, nuclear factor κB (NF-κB), activated protein 1 (AP-1), nuclear erythroid-derived 2-related factor 2 (Nrf2), and cAMP responsive element binding protein (CREB). Depending on dose, radiation quality, and tissue, p53 induces apoptosis or cell-cycle arrest. In low LET radiation therapy, p53 mutations are often associated with therapy resistance, while the outcome of carbon ion therapy seems to be independent of the tumor's p53 status. NF-κB is a central transcription factor in the immune system and exhibits pro-survival effects. Both p53 and NF-κB are activated after ionizing radiation exposure in an ataxia telangiectasia mutated (ATM)-dependent manner. The NF-κB activation was shown to strongly depend on charged particles' LET, with a maximal activation in the LET range of 90-300 keV/μm. AP-1 controls proliferation, senescence, differentiation, and apoptosis. Nrf2 can induce cellular antioxidant defense systems, CREB might also be involved in survival responses. The extent of activation of these transcription factors by charged particles and their interaction in the cellular radiation response greatly influences the destiny of the irradiated and also neighboring cells in the bystander effect.

Loss of IκB kinase β promotes myofibroblast transformation and senescence through activation of the ROS-TGFβ autocrine loop

Using forward and reverse genetics and global gene expression analyses, we explored the crosstalk between the IκB kinase β (IKKβ) and the transforming growth factor β (TGFβ) signaling pathways. We show that in vitro ablation of Ikkβ in fibroblasts led to progressive ROS accumulation and TGFβ activation, and ultimately accelerated cell migration, fibroblast-myofibroblast transformation and senescence. Mechanistically, the basal IKKβ activity was required for anti-oxidant gene expression and redox homeostasis. Lacking this activity, IKKβ-null cells showed ROS accumulation and activation of stress-sensitive transcription factor AP-1/c-Jun. AP-1/c-Jun activation led to up-regulation of the Tgfβ2 promoter, which in turn further potentiated intracellular ROS through the induction of NADPH oxidase (NOX). These data suggest that by blocking the autocrine amplification of a ROS-TGFβ loop IKKβ plays a crucial role in the prevention of fibroblast-myofibroblast transformation and senescence.

Elevated NIBP/TRAPPC9 mediates tumorigenesis of cancer cells through NFκB signaling

Regulatory mechanisms underlying constitutive and inducible NFκB activation in cancer remain largely unknown. Here we investigated whether a novel NIK- and IKK2-binding protein (NIBP) is required for maintaining malignancy of cancer cells in an NFκB-dependent manner. Real-time polymerase chain reaction analysis of a human cancer survey tissue-scan cDNA array, immunostaining of a human frozen tumor tissue array and immunoblotting of a high-density reverse-phase cancer protein lysate array showed that NIBP is extensively expressed in most tumor tissues, particularly in breast and colon cancer. Lentivirus-mediated NIBP shRNA knockdown significantly inhibited the growth/proliferation, invasion/migration, colony formation and xenograft tumorigenesis of breast (MDA-MB-231) or colon (HCT116) cancer cells. NIBP overexpression in HCT116 cells promoted cell proliferation, migration and colony formation. Mechanistically, NIBP knockdown in cancer cells inhibited cytokine-induced activation of NFκB luciferase reporter, thus sensitizing the cells to TNFα-induced apoptosis. Endogenous NIBP bound specifically to the phosphorylated IKK2 in a TNFα-dependent manner. NIBP knockdown transiently attenuated TNFα-stimulated phosphorylation of IKK2/p65 and degradation of IκBα. In contrast, NIBP overexpression enhanced TNFα-induced NFκB activation, thus inhibiting constitutive and TNFα-induced apoptosis. Collectively, our data identified important roles of NIBP in promoting tumorigenesis via NFκΒ signaling, spotlighting NIBP as a promising target in cancer therapeutic intervention.

The mechanisms and significance of up-regulation of RhoB expression by hypoxia and glucocorticoid in rat lung and A549 cells

Small guanosine triphosphate (GTP)‐binding protein RhoB is an important stress sensor and contributes to the regulation of cytoskeletal organization, cell proliferation and survival. However, whether RhoB is involved in the hypoxic response and action of glucocorticoid (GC) is largely unknown. In this study, we investigated the effects of hypoxia or/and GC on the expression and activition of RhoB in the lung of rats and human A549 lung carcinoma cells, and further studied its mechanism and significance. We found that hypoxia and dexamethasone (Dex), a synethic GC, not only significantly increased the expression and activation of RhoB independently but also coregulated the expresion of RhoB in vitro and in vivo. Up‐regulation of RhoB by hypoxia was in part through stabilizing the RhoB mRNA and protein. Inhibiting hypoxia‐activated hypoxia‐inducible transcription factor‐1α (HIF‐1α), c‐Jun N‐terminal kinase (JNK) or extracellular signal‐regulated kinase (ERK) with their specific inhibitors significantly decreased hypoxia‐induced RhoB expression, indicating that HIF‐1α, JNK and ERK are involved in the up‐regulation of RhoB in hypoxia. Furthermore, we found that knockdown of RhoB expression by RhoB siRNA not only significantly reduced hypoxia‐enhanced cell migration and cell survival in hypoxia but also increased the sensitivity of cell to paclitaxel (PTX), a chemotherapeutic agent, and reduced Dex‐enhanced resistance to PTX‐chemotherapy in A549 cells. Taken together, the novel data revealed that hypoxia and Dex increased the expression and activation of RhoB, which is important for hypoxic adaptation and hypoxia‐accelerated progression of lung cancer cells. RhoB also enhanced the resistance of cell to PTX‐chemotherapy and mediated the pro‐survival effect of Dex.