Effect of P2X7R gene silencing by RNA interference on proliferation and phagocytosis of murine macrophage cell line RAW264.7

AIM: To establish a cell line of stable silencing of P2X₇ receptor (P2X₇R) expression through short hairpin RNA (shRNA)-mediated interference in murine RAW264.7 macrophages, and to investigate the proliferation and apoptosis in the cell line. METHODS: Stable silencing of P2X₇R gene in the RAW264.7 cells was achieved by recombinant shRNA plasmid targeting murine P2X₇R gene via liposome mediated transfection, followed by G418 selection. The efficacy of plasmid transfection and P2X₇R silencing in G418 resistant cells was verified by immunofluorescent microscopy and real-time PCR, respectively. The proliferative activity was analyzed by CCK-8 assay and EdU cell proliferation assay. The cell cycle distribution and apoptosis were evaluated by flow cytometry. RESULTS: The expression of P2X₇R at mRNA and protein levels was down-regulated by 80% in sh P2X₇R group compared with negative control (NC) plasmid transfection. In addition, P2X₇R-silencing cells exhibited higher proliferative activity compared with NC and wild-type RAW264.7 cells (P<0.05). Compared with NC cells, P2X₇R silencing resulted in an increase in the phagocytosis of the cells (P<0.05). CONCLUSION: A cell line RAW264.7 of stable silencing of P2X₇R expression was successfully established. P2X₇R gene silencing stimulates the proliferation, and changes phagocytic function in murine RAW264.7 macrophages.     

ox-LDL increases endothelial lipase in RAW264.7 macrophages

AIM: To investigate the effect of oxidized low-density lipoprotein (ox-LDL) on the expression of endothelial lipase (EL) in murine RAW264.7 macrophages. METHODS: RAW264.7 cells were incubated with ox-LDL at concentrations of 0~100 mg/L for 24 h.On the other hand, the cells were incubated with or without PDTC (NF-κB inhibitor) for 30 min and then with ox-LDL (50 mg/L) for 24 h. The expression of EL and p65 was detected by Western blotting. RESULTS: The level of EL was significantly increased after ox-LDL incubation in RAW264.7 cells (P<0.05). NF-κB was activated by ox-LDL at concentration of 50 mg/L for 15~30 min in RAW264.7 cells. The increase in EL induced by ox-LDL was markedly inhibited by a NF-κB inhibitor PDTC (P<0.05). CONCLUSION: ox-LDL significantly increases the expression of EL in RAW264.7 macrophages, which is possibly related to NF-κB activation.     

Effects of intracellular expression of Mycobacterium tuberculosis CFP10-ESAT6 fusion protein on proliferation and apoptosis of mouse macrophages

AIM：To establish Mycobacterium tuberculosis culture filtrate protein 10 (CFP10)-early secretory antigenic target 6 (ESAT6) eukaryotic expression vector and investigate the effect of intracellular expression of CFP10-ESAT6 fusion protein on the proliferation and apoptosis of mouse macrophages (RAW264.7 cells). METHODS：The recombinant plasmid pEGFP-N1/CFP10-ESAT6 was constructed by inserting CFP10-ESAT6 fusion gene into eukaryotic expression vector pEGFP-N1, and then transfected into RAW264.7 cells to express CFP10-ESAT6 fusion protein. The viability of RAW264.7 cells was measured by MTT assay. Flow cytometry was applied to measure the apoptotic rate and Toll-like receptor 2 (TLR2) expression in RAW264.7 cells treated with Mycobacterium tuberculosis 19 kD lipoprotein or staurosporine. RESULTS：The recombinant plasmid pEGFP-N1/CFP10-ESAT6 was successfully constructed and transfected into RAW264.7 cells. Compared with the control cells, intracellular expression of CFP10-ESAT6 fusion protein did not affect the viability of RAW264.7 cells, but could inhibit the apoptosis of RAW264.7 cells treated with Mycobacterium tuberculosis 19 kD lipoprotein. Moreover, CFP10-ESAT6-expressing macrophages had markedly lower expression of TLR2 on the surface. CONCLUSION：Intracellular expression of CFP10-ESAT6 fusion protein has no cytotoxicity on mouse macrophages, but can inhibit the apoptosis of the macrophages treated with Mycobacterium tuberculosis 19 kD lipoprotein through down-regulating the expression of TLR2.     

Low density lipoprotein from patients of diabetes mellitus induces apoptosis of murine macrophages via activating caspase-12 pathway

AIM:To explore the effect of low density lipoprotein from the patients of diabetes mellitus (DM-LDL) on the activation of caspase-12 an important molecule in endoplasmic reticulum stress (ERS)-associated apoptotic pathway, in the murine macrophages, and to clarify the underlying molecular mechanisms of apoptosis. METHODS:Murine macrophage RAW264.7 was exposed to DM-LDL (25, 50 and 100 mg/L), normal low density lipoprotein (n-LDL, 50 mg/L), or tunicamycin (TM, 4 mg/L) for 24 h. Additionally, RAW264.7 macrophages were precultured with 4-phenylbutyric acid (PBA, 5 mmol/L) for 1 h and then exposed to DM-LDL (100 mg/L) for 24 h. The cell viability and apoptosis were detected by MTT assay and flow cytometry with Annexin V-FITC/propidium iodide staining, respectively. Lactate dehydrogenase (LDH) activity in the media was measured by assay kit. The protein level of caspase-12 was determined by Western blot. RESULTS:Similar to TM (an ERS inducer), treatment with DM-LDL caused significantly decrease in the viability and increase in LDH activity in the media and apoptotic rate of the RAW264.7 macrophages (P<0.05). Additionally, DM-LDL induced activation of caspase-12 especially at the dose of 50 and 100 mg/L (P<0.01). However, the ERS inhibitor PBA protected RAW264.7 macrophages from DM-LDL-induced decrease in viability and increase in LDH activity and apoptosis (P<0.05). Furthermore, PBA attenuated DM-LDL-induced activation of caspase-12 (P<0.05). CONCLUSION:DM-LDL may induce apoptosis in RAW264.7 macrophages, and the mechanism may be related to the activation of caspase-12.     

FAK gene silencing enhances chemotherapeutic drug sensitivity in leukemic cells XU Lü-hong1,

AIM: To investigate the effect of focal adhesion kinase (FAK) gene silencing on chemotherapeutic drug sensitivity in leukemic cells. METHODS: Lentiviral-FAK-shRNA was transfected into BCR/ABL-BaF3 leukemic cells. The protein expression of FAK was detected by Western blotting. BCR/ABL-BaF3 leukemic cells were treated with different concentrations of imatinib in vitro, and the apoptosis was determined by labeling with Annexin V. A murine model of leukemia was established and the mice were treated with FAK shRNA and imatinib. Survival time and distribution of leukemic cells in bone marrow and spleen of the mice were monitored. RESULTS: FAK shRNA was successfully constructed and effectively inhibited FAK gene expression. With 5 μmol/L imatinib treatment, the percentages of apoptotic cells in vector control group and FAK shRNA group were (9.76±1.97)% and (21.90±3.20)%, respectively, and significant difference between these 2 groups (P<0.05) was observed. With 50 μmol/L imatinib treatment, the percentages of apoptotic cells in vector control group and FAK shRNA group were (56.10±6.00)% and (82.10±5.70)%, respectively,also with significant difference between these 2 groups (P<0.05). Compared with vector control group, the mice in FAK gene silencing group displayed significantly prolonged survival time. Moreover, 60 days after injection of leukemic cells, the percentages of leukemic cells in bone marrow and spleen of the mice were significantly decreased in FAK gene silencing group as compared with those in vector control group. CONCLUSION: FAK gene silencing promotes the efficacy of chemotherapeutic drug in leukemic cells, indicating that FAK gene silencing might be considered as a new therapeutic strategy for leukemia.     

IL-17A reduces lipid accumulation by up-regulation of ABCA1 expression in Raw264.7 macrophages

AIM:To investigate the effects of interleukin-17A (IL-17A) on the expression of adenosine triphosphate binding cassette transporter A1 (ABCA1) in RAW264.7 macrophages. METHODS:Mouse RAW264.7 macrophages were treated with IL-17A at different concentrations for 6 or 24 h, or treated with IL-17A at the same concentration for different time. The expression of ABCA1 at mRNA and protein levels was determined by RT-qPCR and Western blot, respectively. Cholesterol efflux to apolipoprotein A1 (ApoA-1) was evaluated by NBD-cholesterol method. Lipid accumulation in the cells was evaluated by Oil Red O staining. RESULTS:Compared with control group, IL-17A increased the expression of ABCA1 at protein level in the RAW264.7 cells significantly (P<0.05), but had no effect on the mRNA expression of ABCA1. In addition, cholesterol efflux to ApoA-1 was increased and lipid accumulation in the RAW264.7 cells was decreased obviously after treatment with IL-17A. CONCLUSION:IL-17A increases the protein expression of ABCA1 but not at mRNA level in the RAW264.7 macrophages, which may be correlated with its anti-atherosclerosis effect.     

Effect of microtubule-destabilizing protein stathmin gene silencing on proliferation and apoptosis of nasopharyngeal carcinoma cell line 5-8F

AIM: To investigate the effects of stathmin gene silencing on nasopharyngeal carcinoma cell line 5-8F. METHODS: Double-strand siRNA targeting to stathmin gene was obtained by chemical synthesis and annealing, and was sub-cloned into the vector pGenesil-1.1. The plasmid was introduced into 5-8F cells by liposome-mediated transfection. The gene expression of stathmin, and the proliferation, morphology and apoptosis of the cells were analyzed by Western blotting, MTT assay and flow cytometry. RESULTS: The cell suppression rate in stathmin gene silencing group was (53.01?1.12)%, significantly higher than that in transfection reagent group and in negative control group. The cell apoptotic rate in stathmin gene silencing group was (8.75?0.67)%, also significantly higher than that in transfection reagent group and in negative control group (P<0.05). CONCLUSION: Silencing of stathmin gene in nasopharyngeal carcinoma cells inhibits the cell proliferation and induces cell apoptosis.     

LRRK2/NF-κB signaling modulates inflammatory responses in BCG-infected RAW264.7 macrophages

AIM: To investigate the biological function and potential mechanism of leucine-rich repeat kinase 2 (LRRK2) in RAW264.7 macrophages during Mycobacterium tuberculosis infection. METHODS: The bacillus Calmette-Guerin (BCG)-infected RAW264.7 cell model was established. Colony-forming unit (CFU) analysis was used to determine the mycobacterial viability. The releases of interleukin (IL)-1β, IL-6 and interferon-γ (IFN-γ) in the RAW264.7 cells were detected by ELISA. qPCR and Western blot were used to measure the mRNA and protein expression levels, respectively. RESULTS: LRRK2 was robustly enhanced in the RAW264.7 cells in response to BCG infection. Additionally, silencing of LRRK2 suppressed intracellular growth of mycobacteria during BCG challenge. Moreover, silencing of LRRK2 dramatically attenuated the accumulation of inflammatory cytokines IL-1β, IL-6 and IFN-γ induced by BCG infection. More importantly, LRRK2 modulated BCG-induced inflammatory responses by positively regulating the nuclear factor-κB (NF-κB) signaling pathway. CONCLUSION: LRRK2/NF-κB signaling pathway positively modulates inflammatory responses during BCG infection, which may provide a better understanding of the pathogenesis of tuberculosis and useful information for developing potential therapeutic interventions against the disease.     

Effects of Smo gene silencing on cell activity and apoptosis of human cervical carcinoma HeLa cells

AIM: To investigate the effect of Hedgehog (Hh) signaling pathway on the viability and apoptosis of cervical carcinoma cells by shRNA technique to knock down Smoothened (Smo) gene. METHODS: Smo shRNA was used to transfect the cervical carcinoma HeLa cells. The expression of Smo and Gli1 at mRNA and protein levels in the HeLa cells was determined by RT-PCR and Western blot, respectively. The effect of Smo gene silencing on the growth of the cells was measured by MTT assay. The apoptosis and cell cycle were determined by flow cytometry. RESULTS: Compared with control group, the mRNA and protein expression of Smo and Gli1 were evenly reduced obviously after transfected with Smo shRNA for 72 h (P<0.05). The viability of HeLa cells transfected with Smo shRNA was significantly inhibited. The percentages of the cells in G₀/G₁ phase and early apoptosis rate were obviously higher in Smo shRNA transfection group than those in control group. CONCLUSION: Smo gene silencing effectively inhibits the cell growth and induces the apoptosis of human cervical carcinoma cells.     

Effect of AMPKα2 gene silencing by shRNA recombinant plasmid on chloride-mediated anoxia/reoxygenation injury in rat cardiomyocytes

AIM: To explore the role of AMP-activated protein kinase α2 subunit (AMPKα2) gene in chloride-mediated anoxia/reoxygenation (A/R) injury by transfection of short-hairpin RNA (shRNA) expression vector targeting to AMPKα2 gene into H9c2 cardiomyocytes. METHODS: Recombinant shRNA expression vector pSuper-AMPKα2 targeting to AMPKα2 gene was constructed and transfected into H9c2 cardiomyocytes. The protein expression of AMPKα2 was determined by Western blotting. The cells were divided into 5 groups: control group, A/R group, Cl^--free A/R group, pSuper+Cl^--free A/R group and pSuper-AMPKα2 shRNA+Cl^--free A/R group. After treatment, the cell viability was detected by MTT assay. LDH activity was analyzed with an automatic biochemical analyzer. The apoptotic rate and the level of intracellular ROS was measured by flow cytometry. The activity of SOD and GSH-Px was analyzed by a colorimetric method. RESULTS: The result of sequencing proved that the recombinant plasmid pSuper-AMPKα2 shRNA was correctly constructed. The protein level of AMPKα2 significantly decreased after the plasmid was transfected into the cardiomyocytes. Compared with A/R group, the cell viability and the activity of SOD and GSH-Px were significantly increased, while the activity of LDH, apoptotic rate and ROS production were significantly decreased in Cl^--free A/R group. The protective effect of Cl^--free solution on the A/R-induced injury of cardiomyocytes was abolished, and the ROS production was increased and the activity of SOD and GSH-Px was decreased after the cells were transfected with pSuper-AMPKα2 shRNA. CONCLUSION: Recombinant plasmid pSuper-AMPKα2 shRNA is successfully constructed, and silencing of AMPKα2 gene abolishes the protective effect of Cl^--free solution on A/R injury.     

Effect of RIP3 expression on apoptosis of mouse macrophages infected with BCG

AIM:To investigate the function of receptor-interacting proteins 3 (RIP3) in regulating Bacillus Calmette-Guérin (BCG)-induced apoptosis of mouse macrophages (RAW264.7 cells). METHODS:The RIP3 adenovirus interference vector was constructed and used to infect the RAW264.7 cells, and then the RAW264.7 cells were infected with BCG. The cell viability was measured by MTT assay. The apoptotic rate, mitochondrial membrane potential and production of reactive oxygen species (ROS) were determined by flow cytometry analysis. The protein levels of RIP3 and apoptosis-associated proteins were examined by Western blot. RESULTS:The viability of RAW264.7 cells was decreased after BCG infection. In the meantime, the expression of RIP3 was up-regulated significantly (P<0.01). Compared with BCG infection group, the apoptotic rate and ROS level in BCG and RIP3 adenovirus interference vector co-infection group were significantly decreased (P<0.01). Importantly, RIP3 was able to further promote apoptosis in BCG-infected RAW264.7 cells in part by increasing mitochondrial membrane potential (P<0.01). In addition, Western blot analysis further demonstrated that RIP3 was involved in BCG-induced apoptosis partly through down-regulation of anti-apoptotic protein Bcl-2, and up-regulation of Bax and cleaved caspase-3 (P<0.01). CONCLUSION:RIP3 is involved in BCG-induced apoptosis of RAW264.7 cells, and this process may be achieved by the mitochondrial pathway.     

Preparation of histones and their effects on macrophages

AIM: To prepare histones with different methods and to observe their effects on cell viability and cytokine release by macrophages in vitro.
METHODS: Prokaryotic expression plasmids of histone H3 and histone H4 were constructed by cloning methods. The histones containing GST-tag or His-tag (GST-H3, GST-H3, His-H3, His-H4) were expressed and purified. The histones from eukaryotic cells (RAW264.7 and 293F cells) were extracted with the high salt method. RAW264.7 cells were treated with histones (7.5~50 mg/L) for 4 h and the cell vitality was examined by MTT assay and flow cytometry. The concentrations of IL-6 and TNF-α in the culture supernatants of RAW264.7 cells treated with histones were also detected.
RESULTS: His-H3/H4 and the histones from eukaryotic cells significantly reduced the viability of RAW264.7 cells and induced apoptosis. The effects of histones from different sources on the releases of IL-6 and TNF-α were different.
CONCLUSION: His-H3/His-H4 expressed by prokaryotic plasmids and the histones extracted from eukaryotic cells affect the vitality of macrophages as well as induce late apoptosis and necrosis. Histone may involve in the inflammatory process by promoting the release of inflammatory cytokines.     

Adipophilin induces expression of inflammatory factors through ERK1/2-AP-1 signaling pathway

AIM: To observe the effects of adipose differentiation-related protein (adipophilin) on the expression of inflammatory factors in RAW264.7 macrophage and to clarify the related mechanism. METHODS: The cell models with high expression and low expression of adipophilin were constructed by transfecting PA317 packaging cells with stable high or low expression adipophilin retroviral vectors into the RAW264.7 cells. The concentrations of IL-6, MCP-1 and TNF-α in the cell culture medium were detected by ELISA. The protein levels of AP-1, p-AP-1, ERK1/2 and p-ERK1/2 were measured by Western blot. The protein levels of adipophilin, p-ERK1/2 and p-AP-1 and the releases of the inflammatory factors in the RAW264.7 cells treated with or without ERK1/2 inhibitor PD98059 or AP-1 inhibitor curcumin were determined. RESULTS: The RAW264.7 cells with high expression of adipophilin had higher levels of IL-6, MCP-1 and TNF-α, and higher protein levels of p-AP-1 and p-ERK1/2 than those in the cells with low expression of adipophilin. ERK1/2 inhibitor had no significant effect on the expression of adipophilin, but the protein expression of ERK1/2 and AP-1 was significantly inhibited (P<0.05). The administration of AP-1 inhibitor curcumin had no significant effect on the protein expression of adipophilin and ERK1/2, but the protein expression of AP-1 was significantly inhibited (P<0.05). At the same time, the releases of inflammatory factors IL-6, MCP-1 and TNF-α were significantly decreased. CONCLUSION: Adipophilin may regulate the expression of inflammatory factors through ERK1/2-AP-1 pathway in RAW264.7 macrophages.     

Effects of fibulin-3 expression on malignant pleural mesothelioma cells

AIM: To observe the effects of over-expression and silencing of fibulin-3 on malignant pleural mesothelioma (MPM) cell line SMC-1, and to search for a new method for the treatment of MPM. METHODS: The vectors for fibulin-3 over-expression and short hairpin RNA (shRNA) were constructed, and control vector, fibulin-3 over-expression vector (Exp), over-expression control vector (Exp-NC), interference vector (shRNA1, shRNA2, shRNA3 and shRNA4), and interference control vector (shRNA-NC) were transfected into the SMC-1 cells. The cell cycle distribution and apoptosis were analyzed by flow cytometry. The expression of fibulin-3 before and after interference was determined by real-time PCR and Western blot. RESULTS: Compared with control group, the number of the SMC-1 cells in G₂ phase in Exp group was increased (P<0.05), while that in shRNA2 group was decreased (P<0.05). The results of apoptosis analyzed by flow cytometry showed that compared with control group, the apoptotic rate in Exp group was decreased (P<0.05), while that in shRNA2 group was increased (P<0.05). The mRNA and protein expression levels of fibulin-3 and mesothelin in Exp group were up-regulated, while those in shRNA group were down-regulated (P<0.05).CONCLUSION: The vectors for over-expression and silencing of fibulin-3 are successfully constructed, proving that transfection of Exp and shRNA effectively changes fibulin-3 expression and the SMC-1 cell growth. Fibulin-3 may be a target molecule for MPM treatment.     

The effect of nucleolin on interleukin-1β secretion induced by lipopolysaccharide

AIM: To explore the expression of nucleolin in lipopolysaccharide(LPS)-mediated inflammatory models, and further investigate the role of nucleolin in expression and secretion of LPS-induced interleukin-1β(IL-1β). METHODS: To establish inflammatory models, mice suffered intraperitoneal injection of LPS(15 mg/kg)and RAW264.7 cells were treated with LPS(500 μg/L).Western blotting were applied to identify the expression of nucleolin in these inflammatory models. After over-expression of nucleolin by transient pcDNA3.1-C23 transfection and down-regulation by transient transfection of nucleolin antisense oligonucleotides, the secretion of IL-1β were examined by enzyme-linked immunosorbent assay (ELISA) in LPS-stimulated RAW264.7 cells. RESULTS: Westem blotting assays showed that the 110 kD nucleolin increased in RAW264.7 cells treated with LPS (500 μg/L) and the lung tissues of the mice treated with LPS (15 mg/kg), while the 80 kD component of nucleolin decreased. ELISA showed that LPS-induced IL-1β release in RAW264.7 cells transfected with pcDNA3.1-C23 was higher than that in pcDNA3.1 empty vector transfected cells. LPS-induced IL-1β release in RAW264.7 cells transfected with C23 antisense oligonucleotide was lower than that in normal cells and scramble oligonucleotide transfected cells. CONCLUSION: In LPS-mediated mouse endotoxemia model and LPS-mediated RAW264.7 cell inflammatory model, the expression of 110 kD nucleolin was up-regulated, but 80 kD nucleolin fragment decreased. Nucleolin promoted secretion of LPS-induced IL-1β.     

Effect of CREB-shRNA on mitochondrial morphology and cell apoptosis in OGD/R-induced cortical neurons

AIM: To construct recombinant lentiviral vector with short hairpin RNA (shRNA) of CREB gene, and to investigate the effect of CREB gene silencing on mitochondrial morphology and cell apoptosis in oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cortical neurons. METHODS: Three lentiviral vectors pLentiLox3.7 (PLL) inserted shRNA fragments targeting CREB gene were co-transfected with the packaging plasmids psPAX2 and pMD2.G to the 293T cells, and the virus particles, which was infected with the primary cortical neurons, was encapsulated. The protein expression of CREB was detected by Western blot. The mitochondrial morphology, cell apoptosis and the expression of Bcl-2 and Bax were evaluated by the methods of MitoTracker red, TUNEL and Western blot in OGD/R induced cortical neurons after CREB gene silencing. RESULTS: The pLL-CREB-shRNA1 was the most effective shRNA, which inhibited 80% CREB gene expression in the cortical neurons. The mitochondrial was appeared dot and fragment morphology in OGD/R induced cortical neurons with transfected pLL-CREB-shRNA1 plasmid. In addition, the expression of Bcl-2 was decreased, the expression of Bax, and the apoptosis of the neurons were increased by tranfected with pLL-CREB-shRNA1. CONCLUSION: CREB shRNA recombinant lentiviral vector specifically inhibits the expression of CREB gene. CREB gene silencing promotes the cell apoptosis and mitochondrial morphological changes in the cortical neurons induced by OGD/R.     

Roles of maspin in biological behaviors of PC-3 prostate cancer cells

AIM: To investigate the roles of maspin in the biological behaviors of prostate cancer cells. METHODS: Specific shRNA targeting maspin gene was designed. The plasmid targeting maspin gene was constructed and lentiviral expression system was used for transfection. qRT-PCR and Western blotting were performed to identify the stable maspin-shRNA-transfected PC-3 cells. The expression of apoptosis-related genes was analyzed by qRT-PCR. Dynamic observation of cell growth and doubling time were conducted by an xCELLigence system. The cell death upon proteasome inhibitor treatment was determined by flow cytometry analysis. The expression levels of RelA and RelB were detected by Western blotting. RESULTS: The recombinant plasmid containing maspin-shRNA was successfully constructed. Limited dilution was performed to obtain monoclonal PC-3-siMaspin cells. The doubling time of PC-3-siMaspin cells was 26.83 h while that of PC-3-control cells was 37.95 h. The mRNA expression of bcl-2 and A20 in PC-3-siMaspin cells was increased, while that of bax and bim was down-regulated. The cell death rates of PC-3-control cells and PC-3-siMaspin cells after treated with MG-132 were 27.1% ?5.6% and 7.5% ?2.3% at 8 h, 24.2% ?3.7% and 8.2% ?2.5% at 24 h, and 28.7% ?3.7% and 7.6%?2.5% at 36 h after treatment,respectively. RelA expression was decreased in PC-3-control cells treated with MG-132 while that in PC-3-siMaspin cells stayed unchanged. CONCLUSION: Maspin expression is increased in androgen-independent prostate cancer PC-3 cells. Maspin silencing significantly reduces the doubling time and accelerates the cell growth. Maspin silencing markedly reduces the sensitivity of PC-3 cells to proteasome inhibitor, which may be linked to the abolishment of RelA degradation.