Alpha B‐crystallin promotes the invasion and metastasis of gastric cancer via NF‐κB‐induced epithelial‐mesenchymal transition

Alpha B‐crystallin (CRYAB) is overexpressed in a variety of cancers. However, little is known about its specific function and regulatory mechanism in gastric cancer. Here, we first explore the role of CRYAB in gastric cancer progression and metastasis. The expression of CRYAB was determined by western blot and immunohistochemistry in gastric cancer tissues. Besides, methods including stably transfected against CRYAB into gastric cancer cells, western blot, migration and invasion assays in vitro and metastasis assay in vivo were also conducted. The expression of CRYAB is up‐regulated in gastric cancer tissues compared with matched normal tissues. High expression level of CRYAB is closely correlated with cancer metastasis and shorter survival time in patients with gastric cancer. Additionally, CRYAB silencing significantly suppresses epithelial‐mesenchymal transition (EMT), migration and invasion of gastric cancer cells in vitro and in vivo, whereas CRYAB overexpression dramatically reverses these events. Mechanically, CRYAB facilitates gastric cancer cells invasion and metastasis via nuclear factor‐κ‐gene binding (NF‐κB)‐regulated EMT. These findings suggest that CRYAB expression predicts a poor prognosis in patients with gastric cancer. Besides, CRYAB contributes to gastric cancer cells migration and invasion via EMT, mediated by the NF‐κB signalling pathway, thus possibly providing a novel therapeutic target for gastric cancer.     

MiR‐802 causes nephropathy by suppressing NF‐κB‐repressing factor in obese mice and human

Obesity is associated with significant microvascular complications including renal injuries and may induce end‐stage renal disease. Emerging studies have demonstrated microRNAs (miRNAs) are potential mediators in the pathophysiological process of nephropathy. The present study aimed to investigate the role of miR‐802 in obesity‐related nephropathy and potential molecular mechanisms. Through utilizing obese mouse model and human subjects, we explored the therapeutic benefits and clinical application of miR‐802 in protecting against nephropathy. Renal miR‐802 level was positively correlated with functional parameters, including blood urea nitrogen and creatinine in obese mice. Specific silencing of renal miR‐802 improved high fat diet (HFD)‐induced renal dysfunction, structural disorders and fibrosis. The up‐regulated inflammatory response and infiltrated macrophages were also significantly decreased in miR‐802 inhibitor‐treated obese mice. Mechanistically, miR‐802 directly bond to 3?‐UTR of NF‐κB‐repressing factor (NRF) and suppressed its expression. In clinical study, the circulating miR‐802 level was significantly increased in obese subjects, and positively correlated with plasma creatinine level but negatively correlated with creatinine clearance. Taken together, our findings provided evidence that miR‐802/NRF signalling was an important pathway in mediating obesity‐related nephropathy. It is a possible useful clinical approach of treating miR‐802 inhibitor to combat nephropathy.     

Alkannin attenuates lipopolysaccharide‐induced lung injury in mice via Rho/ROCK/NF‐κB pathway

We investigated the effects and associated mechanism of alkannin (AL) on lipopolysaccharide (LPS)‐induced acute lung injury in a mouse model. Pretreatment with AL in vivo significantly reduced the lung wet/dry weight ratio and inhibited lung myeloperoxidase activity and malondialdehyde content, while increasing superoxide dismutase activity. Hematoxylin and eosin staining demonstrated that AL attenuated lung histopathological changes. In addition, AL‐inhibited overproduction of proinflammatory cytokines in bronchoalveolar lavage fluid and lung tissues in LPS‐injured mice and LPS‐exposed A549 cells. Further analysis showed that AL‐inhibited induction of the Rho/ROCK/NF‐κB pathway via LPS‐induced inflammation in mice and A549 cells. Fasudil, a selective ROCK inhibitor, showed similar effects. Overall, the findings indicate that AL suppresses the expression of messenger RNAs and proteins associated with Rho/ROCK/NF‐κB signaling to effectively ameliorate lung injury.     

β‐Carotene Induces Apoptosis in Human Esophageal Squamous Cell Carcinoma Cell Lines via the Cav‐1/AKT/NF‐κB Signaling Pathway

β‐carotene, a type of terpenoid, has many metabolic and physiological functions. In particular, β‐carotene has an antitumor effect. However, the efficacy of β‐carotene against esophageal squamous cell carcinoma (ESCC) remains unclear. In our study, β‐carotene inhibited the growth of ESCC cells and downregulated expression of the Caveolin‐1 (Cav‐1) protein. Cav‐1 protein was expressed only in ESCC cells, not in Het‐1A cells. Moreover, β‐carotene triggered apoptosis, induced cell cycle G0?G1 phase arrest, and inhibited cell migration. To explore the mechanism involved in these processes, we further examined the effect of β‐carotene on the Cav‐1‐mediated AKT/NF‐κB pathway. The results showed that the level of AKT and NF‐κB phosphorylation was dramatically inhibited, which led to an increase in the Bax/Bcl‐2 ratio. Correspondingly, the activity of Caspase‐3 was also enhanced. These data suggest that β‐carotene has an antiproliferative role in ESCC cells and may be a promising chemotherapeutic agent for use against ESCC cells.     

TNIP1‐mediated TNF‐α/NF‐κB signalling cascade sustains glioma cell proliferation

As a malignant tumour of the central nervous system, glioma exhibits high incidence and poor prognosis. Although TNIP1 and the TNF‐α/NF‐κB axis play key roles in immune diseases and inflammatory responses, their relationship and role in glioma remain unknown. Here, we revealed high levels of TNIP1 and TNF‐α/NF‐κB in glioma tissue. Glioma cell proliferation was activated with TNF‐α treatment and showed extreme sensitivity to the TNF receptor antagonist. Furthermore, loss of TNIP1 disbanded the A20 complex responsible for IκB degradation and NF‐κB nucleus translocation, and consequently erased TNFα‐induced glioma cell proliferation. Thus, our investigation uncovered a vital function of the TNIP1‐mediated TNF‐α/NF‐κB axis in glioma cell proliferation and provides novel insight into glioma pathology and diagnosis.     

Optineurin suppression causes neuronal cell death via NF‐κB pathway

Mutations in more than 10 genes are reported to cause familial amyotrophic lateral sclerosis (ALS). Among these genes, optineurin (OPTN) is virtually the only gene that is considered to cause classical ALS by a loss‐of‐function mutation. Wild‐type optineurin (OPTN^WT) suppresses nuclear factor‐kappa B (NF‐κB) activity, but the ALS‐causing mutant OPTN is unable to suppress NF‐κB activity. Therefore, we knocked down OPTN in neuronal cells and examined the resulting NF‐κB activity and phenotype. First, we confirmed the loss of the endogenous OPTN expression after siRNA treatment and found that NF‐κB activity was increased in OPTN‐knockdown cells. Next, we found that OPTN knockdown caused neuronal cell death. Then, overexpression of OPTN^WT or OPTN^E50K with intact NF‐κB‐suppressive activity, but not overexpression of ALS‐related OPTN mutants, suppressed the neuronal death induced by OPTN knockdown. This neuronal cell death was inhibited by withaferin A, which selectively inhibits NF‐κB activation. Lastly, involvement of the mitochondrial proapoptotic pathway was suggested for neuronal death induced by OPTN knockdown. Taken together, these results indicate that inappropriate NF‐κB activation is the pathogenic mechanism underlying OPTN mutation‐related ALS.

     

Central dopamine action modulates neuropeptide‐controlled appetite via the hypothalamic PI3K/NF‐κB‐dependent mechanism

Hypothalamic neuropeptides, including neuropeptide Y (NPY) and proopiomelanocortin (POMC), have been found to control the appetite‐suppressing effect of amphetamine (AMPH). In this study, we have examined whether dopamine receptor (DAR), phosphatidylinositol 3‐kinase (PI3K) and nuclear factor‐kappaB (NF‐κB) are involved in AMPH's action. We administered AMPH to rats once a day for 4 days and assessed and compared changes in hypothalamic NPY, melanocortin receptor 4 (MC4R), PI3K, pAkt and NF‐κB expression. We found that the inhibition of DAR increased NPY, but decreased MC4R, PI3K and NF‐κB expression, compared with AMPH‐treated rats. Moreover, MC4R, PI3K, pAkt and NF‐κB increased with the maximum response on Day 2, which was consistent with the response of feeding behavior, but was opposite to the expression of NPY. Furthermore, we found that the intracerebroventricular infusion of the PI3K inhibitor or NF‐κB antisense could attenuate AMPH‐induced anorexia, and partially reverse the expression of NPY, MC4R, PI3K, Akt and NF‐κB back toward a normal level. We, therefore, suggest that DAR–PI3K–NF‐κB signaling in the hypothalamus plays functional roles in the modulation of NPY and POMC neurotransmissions and in the control of AMPH‐evoked appetite suppression.     

Anemonin attenuates osteoarthritis progression through inhibiting the activation of IL‐1β/NF‐κB pathway

The osteoarthritis (OA) progression is now considered to be related to inflammation. Anemonin (ANE) is a small natural molecule extracted from various kinds of Chinese traditional herbs and has been shown to inhibiting inflammation response. In this study, we examined whether ANE could attenuate the progression of OA via suppression of IL‐1β/NF‐κB pathway activation. Destabilization of the medial meniscus (DMM) was performed in 10‐week‐old male C57BL/6J mice. ANE was then intra‐articularly injected into joint capsule for 8 and 12 weeks. Human articular chondrocytes and cartilage explants challenged with interleukin‐1β (IL‐1β) were treated with ANE. We found that ANE delayed articular cartilage degeneration in vitro and in vivo. In particular, proteoglycan loss and chondrocyte hypertrophy were significantly decreased in ANE ‐treated mice compared with vehicle‐treated mice. ANE decreased the expressions of matrix metalloproteinase‐13 (MMP13), A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), collagen X (Col X) while increasing Aggrecan level in murine with DMM surgery. ANE treatment also attenuated proteoglycan loss in human cartilage explants treated with IL‐1β ex vivo. ANE is a potent protective molecule for OA; it delays OA progression by suppressing ECM loss and chondrocyte hypertrophy partially by suppressing IL‐1β/NF‐κB pathway activation.     

RTP801 Regulates Maneb‐ and Mancozeb‐Induced Cytotoxicity via NF‐κB

Environmental factors have been implicated in the pathogenesis of neurodegenerative diseases. Maneb (MB) and mancozeb (MZ) have been extensively used as pesticides. Exposure to MB lowers the threshold for dopaminergic damage triggered by 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine. MB and MZ potentiate 1‐methyl‐4‐phenylpyridium (MPP⁺)‐induced cytotoxicity in rat pheochromocytoma (PC12) cells partially via nuclear factor kappa B (NF‐κB) activation. RTP801 dramatically increased by oxidative stresses and DNA damage is the possible mechanism of neurotoxins‐induced cell death in many studies. This study demonstrated that MB and MZ induced DNA damage as seen in comet assay. The expressions of RTP801 protein and mRNA were elevated after MB and MZ exposures. By knocking down RTP801 using shRNA, we demonstrated that NF‐κB activation by MB and MZ was regulated by RTP801 and cell death triggered by MB and MZ was associated with RTP801 elevation. This revealed that the toxic mechanisms of dithiocarbamates are via the cross talk between RTP801 and NF‐κB.     

NDR1/STK38 potentiates NF‐κB activation by its kinase activity

Human NDR1/STK38 belongs to the nuclear‐Dbf2‐related (NDR) family of Ser/Thr kinases. It has been implicated to function in centrosome duplication, control of cell cycle and apoptosis. However, the mechanism of NDR1 signaling pathway remains largely elusive. Here, we report a novel role of NDR1 in NF‐κB activation. By overexpression, NDR1 potentiates NF‐κB activation induced by TNFα, whereas knockdown of NDR1 expression inhibits NF‐κB activation induced by TNFα. Coimmunoprecipitation shows that NDR1 interacts with multiple signal components except p65 in NF‐κB signaling pathway. Furthermore, both phosphorylation and kinase dead mutants of NDR1 lose their synergistic effects on TNFα‐induced NF‐κB activation. siRNA oligo against NDR1 and kinase dead mutant as well mainly block the NF‐κB activation induced by TRAF2 but not RIP1. Furthermore, kinase dead mutant of NDR1 fails to interact with TRAF2. Taken together, our findings suggest an unknown function of NDR1, which may regulate NF‐κB activation by its kinase activity. Copyright © 2012 John Wiley & Sons, Ltd.