Involvement of NF-kappaB activation in the apoptosis induced by extracellular adenosine in human hepatocellular carcinoma HepG2 cells

Exploration of the Potential Mechanism of Calculus Bovis in Treatment of Primary Liver Cancer by Network Pharmacology

AIM AND OBJECTIVE

Calculus Bovis (CB) has been employed to treat diseases for a long time. It has been identified to play significant anti-inflammatory and anti-tumor roles. However, the mechanism of treating primary liver cancer (PLC) remains to be revealed. This study aims to clarify the molecules and mechanisms of CB in treating PLC.

MATERIALS AND METHODS

After oral bioavailability (OB) and drug-likeness (DL) screening, 15 small molecules were identified as the potential ingredients against PLC. Following this, related targets network constructions and pathways were applied to clarify the mechanism of CB in treating PLC. An in vitro experiment was carried out to identify the function of CB in treating PLC.

RESULTS

Eleven compounds of CB were identified that play an anti-PLC role, including oleanolic acid, ergosterol, ursolic acid, etc. The potential targets which were observed include IL6, MAPK-8, VEGFA, Caspase-3, etc. Further analysis showed that the mechanism of CB in the treatment of PLC involved apoptosis-related pathways and immune-related pathways.

CONCLUSION

In summary, the current study combines network pharmacology and in vitro experiments to reveal the mechanism of CB against PLC. We concluded that 11 ingredients of CB have an anti-PLC effect. Furthermore, CB plays a key role in treating PLC mainly by apoptosisrelated pathways and immune-related pathways. Our experiment verifies that CB promotes the apoptosis of SMMC-7721.

Role of the Mitochondrial Citrate-malate Shuttle in Hras12V-Induced Hepatocarcinogenesis: A Metabolomics-Based Analysis

The activation of the Ras signaling pathway is a crucial process in hepatocarcinogenesis. Till now, no reports have scrutinized the role of dynamic metabolic changes in Ras oncogene-induced transition of the normal and precancerous liver cells to hepatocellular carcinoma in vivo. In the current study, we attempted a comprehensive investigation of Hras12V transgenic mice (Ras-Tg) by concatenating nontargeted metabolomics, transcriptomics analysis, and targeted-metabolomics incorporating [U-¹³C] glucose. A total of 631 peaks were detected, out of which 555 metabolites were screened. Besides, a total of 122 differently expressed metabolites (DEMs) were identified, and they were categorized and subtyped with the help of variation tendency analysis of the normal (W), precancerous (P), and hepatocellular carcinoma (T) liver tissues. Thus, the positive or negative association between metabolites and the hepatocellular carcinoma and Ras oncogene were identified. The bioinformatics analysis elucidated the hepatocarcinogenesis-associated significant metabolic pathways: glycolysis, mitochondrial citrate-malate shuttle, lipid biosynthesis, pentose phosphate pathway (PPP), cholesterol and bile acid biosynthesis, and glutathione metabolism. The key metabolites and enzymes identified in this analysis were further validated. Moreover, we confirmed the PPP, glycolysis, and conversion of pyruvate to cytosol acetyl-CoA by mitochondrial citrate-malate shuttle, in vivo, by incorporating [U-¹³C] glucose. In summary, the current study presented the comprehensive bioinformatics analysis, depicting the Ras oncogene-induced dynamic metabolite variations in hepatocarcinogenesis. A significant finding of our study was that the mitochondrial citrate-malate shuttle plays a crucial role in detoxification of lactic acid, maintenance of mitochondrial integrity, and enhancement of lipid biosynthesis, which, in turn, promotes hepatocarcinogenesis.

LncRNA MEG3 contributes to adenosine-induced cytotoxicity in hepatoma HepG2 cells by downregulated ILF3 and autophagy inhibition via regulation PI3K-AKT-mTOR and beclin-1 signaling pathway

Adenosine is a promising cytotoxic reagent for tumors, long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) has been indicated to play critical roles in tumorigenesis, ILF3 has been recognized as a MEG3-binding protein, however, the roles of adenosine and MEG3 on hepatoma are still ambiguous. To clarify the effects of MEG3 on the adenosine-induced cytotoxicity in hepatoma, MEG3 and ILF3 lentivirus were transduced into human hepatoma HepG2 cells to stimulate overexpression of MEG3 (OE MEG3) and overexpression of ILF3 (OE ILF3), furthermore, ILF3 small interfering RNA (siRNA) was also applied to downregulate the expression of ILF3. In this study, autophagy was markedly inhibited by low concentration of adenosine, which present by not only inhibited transformation from LC3-I to LC3-II and autophagosomes formation, but also the elevation of mTOR and reduction of beclin-1 proteins. Furthermore, low concentration of adenosine also exerted marked cytotoxicity representing induced cell apoptosis together with reductions of cell viability and migration, which were also markedly enhanced by OE MEG3. Novelly and excitingly, adenosine markedly stimulated MEG3 expression, OE MEG3 markedly decreased the ILF3 expression in HepG2 cells, and the adenosine-induced autophagy inhibition, together with the ratio of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR were also boosted by OE MEG3. More interestingly, OE ILF3 increased autophagy, whereas downregulated ILF3, especially in the case of adenosine, led to marked autophagy inhibition by decreasing beclin-1. The present study demonstrates autophagy inhibition is involved in the adenosine-induced cytotoxicity in HepG2 cells, the cytotoxicity can be synergized by OE MEG3 via downregulated ILF3 to activate PI3K/Akt/mTOR and inactivate the beclin-1 signaling pathway. In conclusion, MEG3 and inhibition of autophagy might be potential targets for augmenting adenosine-induced cytotoxicity in hepatoma.

Hopea odorata extract inhibits hepatocellular carcinoma via induction of caspase-dependent apoptosis

Introduction

Cancer is a disease with a global burden and is a major and increasing threat to public health. The demand for new modalities to treat and prevent cancer is high. Given the toxic side effects of standard treatments, such as chemotherapy, there is greater research interest in naturally derived compounds due to their selective toxicity to cancer cells. This study aimed to test the anticancer activity of a crude extract of Hopea odorata on hepatocellular carcinoma (HCC) HepG2 cell line.

Methods

Methanol extracts of H. odorata were prepared from the bark of H. odorata plants (H. odorata extract). The in vitro cytotoxicity of H. odorata extracts on human HCC cell line HepG2 compared to normal human fibroblasts (HFs) was assessed by Alamar Blue assay. Caspase-3/7 was detected using a reagent that consists of DEVD peptide conjugated to a nucleic acid-binding dye. Apoptosis induction by the H. odorata plant extract on HepG2 was evaluated by Annexin V/7-AAD using flow cytometry. Disintegrated nuclei of plant-treated cells were observed under a fluorescent microscope using Hoechst and propidium iodide (PI) staining. In addition, using the Hoechst/PI staining technique, the ratio of dead to total cells was determined by distinguishing Hoechst and PI fluorescent signals.

Results

We found that the IC₅₀ value of H. odorata extract on HepG2 was 12.67±5 µg/mL and on HF was 44±3 µg/mL. The IC₅₀ value of doxorubicin on HepG2 was 153.3±15 ng/mL and on HF was 6.3±0.6 ng/mL. The selectivity index (SI) of H. odorata extract for HepG2 cells was ~3.48, while the SI of doxorubicin for HepG2 cells was ~0.04. The ratio of dead to total cells increased in a dose-dependent manner for HepG2 cells when observed under a fluorescent microscope, while the ratio of dead to total cells barely changed for HF cells. The H. odorata extract inhibited HepG2 cells via the activation of caspase-3/7. At 250 µg/mL concentration of the H. odorata extract, 35% of HepG2 cells were induced into apoptosis, and the cells exhibited disintegrated nuclei under a fluorescent microscope.

Conclusion

These findings demonstrate that the methanolic bark extracts of H. odorata plant induce apoptosis and selective cytotoxicity toward HepG2 but not HF. Therefore, purification of compounds from H. odorata bark extracts may be useful as anticancer agents, and thus, more studies are warranted to investigate the anticancer properties of H. odorata.

Co-culture of hepatoma cells with hepatocytic precursor (stem-like) cells inhibits tumor cell growth and invasion by downregulating Akt/NF-κB expression

Hepatocytic stem cells (HSCs) have inhibitory effects on hepatocarcinoma cells. The present study investigated the effects of HSC activity in hepatocarcinoma cells in vitro. A Transwell co-culture system of hepatocytic precursor (stem-like) WB-F344 cells and hepatoma CBRH-7919 cells was used to assess HSC activity in metastasized hepatoma cells in vitro. Nude mouse xenografts were used to assess HSC activity in vivo. Co-culture of hepatoma CBRH-7919 cells with WB-F344 cells suppressed the growth and colony formation, tumor cell migration and invasion capacity of CBRH-7919 cells. The nude mouse xenograft assay demonstrated that the xenograft size of CBRH-7919 cells following co-culture with WB-F344 cells was significantly smaller compared with that of control cells. Furthermore, the expression levels of the epithelial markers E-cadherin and β-catenin were downregulated, while the mesenchymal markers α-SMA and vimentin were upregulated. Co-culture of CBRH-7919 cells with WB-F344 cells downregulated NF-κB and phospho-Akt expression. In conclusion, hepatocytic precursor (stem-like) WB-F344 cells inhibited the growth, colony formation and invasion capacity of metastasized hepatoma CBRH-7919 cells in vitro and in vivo by downregulating Akt/NF-κB signaling.

microRNA-622 acts as a tumor suppressor in hepatocellular carcinoma

microRNAs (miRNAs) are important regulators of tumor development and progression. In this study, we aimed to explore the expression and role of miR-622 in hepatocellular carcinoma (HCC). We found that miR-622 was significantly downregulated in human HCC specimens compared to adjacent noncancerous liver tissues. miR-622 downregulation was significantly associated with aggressive parameters and poor prognosis in HCC. Enforced expression of miR-622 significantly decreased the proliferation and colony formation and induced apoptosis of HCC cells. In vivo studies demonstrated that miR-622 overexpression retarded the growth of HCC xenograft tumors. Bioinformatic analysis and luciferase reporter assays revealed that miR-622 directly targeted the 3'-untranslated region (UTR) of mitogen-activated protein 4 kinase 4 (MAP4K4) mRNA. Ectopic expression of miR-622 led to a significant reduction of MAP4K4 expression in HCC cells and xenograft tumors. Overexpression of MAP4K4 partially restored cell proliferation and colony formation and reversed the induction of apoptosis in miR-622-overexpressing HCC cells. Inhibition of JNK and NF-κB signaling phenocopied the anticancer effects of miR-622 on HCC cells. Taken together, miR-622 acts as a tumor suppressor in HCC and restoration of miR-622 may provide therapeutic benefits in the treatment of HCC.

Involvement of endoplasmic reticulum stress and p53 in lncRNA MEG3-induced human hepatoma HepG2 cell apoptosis

Long non-coding RNAs (lncRNAs) play important roles in diverse biological processes. Although downregulation of lncRNA maternally expressed gene 3 (MEG3) has been identified in several types of cancers, little is known concerning its biological role and regulatory mechanism in hepatoma. Our previous studies demonstrated that MEG3 induces apoptosis in a p53-dependent manner. The aim of the present study was to determine whether endoplasmic reticulum (ER) stress is involved in MEG3‑induced apoptosis. Recombinant lentiviral vectors containing MEG3 (Lv‑MEG3) were constructed and transfected into HepG2 cells. A 3‑(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, RT‑PCR, flow cytometry, western blot analysis, immunofluorescence and immunohistochemistry were applied. Transfected HepG2 cells were also transplanted into nude mice, and the tumor growth curves were determined. The results showed that the recombinant lentivirus of MEG3 was transfected successfully into the HepG2 cells and the expression level of MEG3 was significantly increased. Ectopic expression of MEG3 inhibited HepG2 cell proliferation in vitro and in vivo, and also induced apoptosis. Ectopic expression of MEG3 increased ER stress‑related proteins 78‑kDa glucose‑regulated protein (GRP78), inositol‑requiring enzyme 1 (IRE1), RNA‑dependent protein kinase‑like ER kinase (PERK), activating transcription factor 6 (ATF6), C/EBP homologous protein (CHOP), caspase‑3, as well as p53 and NF‑κB expression accompanied by NF‑κB translocation from the cytoplasm to the nucleus. Furthermore, inhibition of NF‑κB with Bay11‑7082 decreased p53 expression in the MEG3‑transfected cells. These results indicate that MEG3 inhibits cell proliferation and induces apoptosis, partially via the activation of the ER stress and p53 pathway, in which NF‑κB signaling is required for p53 activation in ER stress.

Dopamine impairs functional integrity of rat hepatocytes through nuclear factor kappa B activity modulation: An in vivo, ex vivo, and in vitro study

Dopamine (DA) is commonly used to maintain the hemodynamic stability of brain-dead donors despite its controversial effects on organ functions. This study aimed at examining the hemodynamic effect of DA in a rat brain-dead model in vivo, alteration of hepatocyte integrity in liver grafts after ex vivo preservation, and changes in cultured clone-9 hepatocytes including cellular viability, cell cycle, apoptotic regulators, and lipopolysaccharide (LPS)-stimulated nuclear factor kappa B (NF-κB) signaling machinery. Although in vivo findings demonstrated enhanced portal venous blood flow and hepatic microcirculatory perfusion after DA infusion, no apparent advantage was noted in preserving hepatocyte integrity ex vivo. In vitro, prolonged exposure to high-dose DA reduced proliferation and induced G1 growth arrest of clone-9 hepatocytes with concomitant decreases in B cell lymphoma 2 (BCL2)/B cell lymphoma 2-associated X protein (BAX) and heat shock protein 70/BAX protein ratios and intracellular NF-κB p65. Moreover, DA pretreatment suppressed LPS-elicited inhibitor of κBα phosphorylation and subsequent NF-κB nuclear translocation, suggesting that DA may down-regulate NF-κB signaling, thereby reducing expression of antiapoptotic regulators, such as BCL2. In conclusion, despite augmentation of hepatic perfusion, DA infusion failed to preserve hepatocyte integrity both in vivo and ex vivo. In vitro findings demonstrated that high-dose DA may hamper the function of NF-κB signaling machinery and eventually undermine functional integrity of hepatocytes in liver grafts.

The role of constitutive nitric-oxide synthase in ultraviolet B light-induced nuclear factor κB activity

NF-κB is a transcription factor involved in many signaling pathways that also plays an important role in UV-induced skin tumorigenesis. UV radiation can activate NF-κB, but the detailed mechanism remains unclear. In this study, we provided evidence that the activation of constitutive nitric-oxide synthase plays a role in regulation of IκB reduction and NF-κB activation in human keratinocyte HaCaT cells in early phase (within 6 h) post-UVB. Treating the cells with l-NAME, a selective inhibitor of constitutive nitric-oxide synthase (cNOS), can partially reverse the IκB reduction and inhibit the DNA binding activity as well as nuclear translocation of NF-κB after UVB radiation. A luciferase reporter assay indicates that UVB-induced NF-κB activation is totally diminished in cNOS null cells. The cNOS-mediated reduction of IκB is likely due to the imbalance of nitric oxide/peroxynitrite because treating the cells with lower (50 μm), but not higher (100-500 μm), concentration of S-nitroso-N-acetylpenicillamine (SNAP) can reverse the effect of l-NAME in partial restore IκB level post-UVB. Our data also showed that NF-κB activity was required for maintaining a stable IκB kinase α subunit (IKKα) level because treating the cells with NF-κB or cNOS inhibitors could reduce IKKα level upon UVB radiation. In addition, our data demonstrated that although NF-κB protects cells from UVB-induced death, its pro-survival activity was likely neutralized by the pro-death activity of peroxynitrite after UVB radiation.

Synergistic effect of pyrrolidine dithiocarbamate and cisplatin in human cervical carcinoma

We aimed to delineate how pyrrolidine dithiocarbamate (PDTC) affects nuclear factor κB (NF-κB) and to determine its antitumor activity alone and in combination with cisplatin in human cervical cancer SiHa cells. The SiHa cells were treated with various concentrations of PDTC and/or cisplatin at various time intervals. Cell proliferation and apoptosis were determined using a water-soluble tetrazolium salt 8 assay and flow cytometry. Electrophoretic mobility shift assay was used to assess NF-κB activity. Pyrrolidine dithiocarbamate (2.5-100 µmol/L) was found to inhibit the growth of SiHa cell lines. Cisplatin (0.01-20.0 μg/mL) and PDTC (2.5-20.0 µmol/L) combined demonstrated additive inhibitive effects on cell growth and increased the level of apoptosis. In addition, PDTC blocked cisplatin-induced activation of NF-κB, leading to enhanced apoptosis and increased chemosensitivity to cisplatin. Taken together, PDTC has significant potential as a chemotherapy agent, alone or in combination with cisplatin.

Enhanced antitumor effects of adenoviral-mediated siRNA against GRP78 gene on adenosine-induced apoptosis in human hepatoma HepG2 cells

Our previous studies show that adenosine-induced apoptosis is involved in endoplasmic reticulum stress in HepG2 cells. In this study, we have investigated whether knockdown of GRP78 by short hairpin RNA (shRNA) increases the cytotoxic effects of adenosine in HepG2 cells. The adenovirus vector-delivered shRNA targeting GRP78 (Ad-shGRP78) was constructed and transfected into HepG2 cells. RT-PCR assay was used to determine RNA interference efficiency. Effects of knockdown of GRP78 on adenosine-induced cell viabilities, cell-cycle distribution and apoptosis, as well as relative protein expressions were determined by flow cytometry and/or Western blot analysis. The intracellular Ca2+ concentration was detected by laser scanning confocal microscope. Mitochondrial membrane potential (ΔΨm) was measured by a fluorospectrophotometer. The results revealed that GRP78 mRNA was significantly downregulated by Ad-shGRP78 transfection. Knockdown of GRP78 enhanced HepG2 cell sensitivity to adenosine by modulating G0/G1 arrest and stimulating Bax, Bak, m-calpain, caspase-4 and CHOP protein levels. Knockdown of GRP78 worsened cytosolic Ca2+ overload and ΔΨm loss. Knockdown of caspase-4 by shRNA decreased caspase-3 mRNA expression and cell apoptosis. These findings indicate that GRP 78 plays a protective role in ER stress-induced apoptosis and show that the combination of chemotherapy drug and RNA interference adenoviruses provides a new treatment strategy against malignant tumors.

Apoptosis induced by adenosine involves endoplasmic reticulum stress in EC109 cells

Apoptosis plays a critical role in the development and homeostasis of multicellular organisms, and endoplasmic reticulum stress (ERS) is one of the intrinsic apoptosis pathways. Previous studies have shown that adenosine induces apoptosis in several cancer cell lines. However, the molecular mechanism remains poorly understood. In this study, we explored whether adenosine triggers apoptosis of EC109 esophageal carcinoma (EC) cells by ERS. The MTT assay was used to determine cell proliferation; cell cycle detection (FCM) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to determine cell apoptosis. The subcellular distribution and expression of the ERS-related proteins GRP78, cleaved caspase-3, cleaved caspase-4, CHOP and NF-κB p65 were detected by western blot techniques. NF-κB activation was measured by electrophoretic mobility shift assay (EMSA). The MTT assay demonstrated that adenosine inhibited EC109 cell proliferation in a dose- and time-dependent manner. FCM and TUNEL assay verified that adenosine caused an apoptotic peak in cell cycle arrest and a higher percentage of apoptotic cells. Western blot analysis confirmed that the expression of GRP78, cleaved caspase-4, CHOP, NF-κB p65 and cleaved caspase-3 were upregulated in a dose-dependent manner after adenosine treatment. EMSA revealed that adenosine activated NF-κB p65. This is the first demonstration that adenosine inhibits cell proliferation, increases GRP78 and NF-κB p65 expression and induces apoptosis by CHOP and caspase-4 pathways. The ERS pathway is involved in adenosine-induced apoptosis in EC109 cells.

Effect of NF-κB inhibitors on the chemotherapy-induced apoptosis of the colon cancer cell line HT-29

This study aimed to investigate the impact of the combined use of the nuclear factor-κB (NF-κB) inhibitors pyrrolidine dithiocarbamate (PDTC), bortezomib or SN50, and the chemotherapy agents arsenic acid (As₂O₃), fluorouracil (5FU), oxaliplatin or paclitaxel on the growth and apoptosis of HT-29 cells. Cell morphology was observed using inverted microscopy, and cell viability and apoptosis were assessed using the MTT assay and flow cytometry, respectively. The activities of NF-κB were analyzed by western blotting and electrophoretic mobility shift assay (EMSA). Cell growth was significantly inhibited by As₂O₃, oxaliplatin and paclitaxel in a time- and concentration-dependent manner (P<0.05), while 5FU inhibited cell growth in a time-dependent manner only (P<0.05). The growth inhibition rate and apoptosis induction ratio were increased following the combined treatment of the chemotherapy agent and NF-κB inhibitor. The expression of NF-κB p65 was upregulated when cells were treated with a chemotherapy drug, however it was downregulated following combined treatment or treatment with an NF-κB inhibitor alone. In conclusion, an NF-κB inhibitor combined with a chemotherapy drug effectively inhibited cell proliferation, induced cell apoptosis and inhibited NF-κB activity to enhance the chemotherapeutic sensitivity of HT-29 cells.

Adenosine induces cell-cycle arrest and apoptosis in androgen-dependent and -independent prostate cancer cell lines, LNcap-FGC-10, DU-145, and PC3

BACKGROUND

Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via intrinsic and extrinsic pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the DU-145, PC3, and LNcap-FGC10 human prostate cancer cells.

METHODS

To observe cell viability and proliferation, MTT assay, cell counting, and BrdU assay were carried out in DU-145, PC3, and LNcap-FGC10 cells. Apoptosis was assessed with the analysis of cell cycle, Hoechst 33258 staining, propidium iodide and annexin-V staining, reactive oxygen species (ROS) formation, mitochondrial membrane potential (ΔΨM) measurement, caspase-3 activity assay, Bcl-2 and Bax protein expression. Moreover, the expression of adenosine receptors and the effects of adenosine receptor (A(1) , A(2a) , and A(3) ) antagonists were examined.

RESULT

Adenosine significantly reduced cell proliferation in a dose-dependent manner in DU-145, PC3, and LNcap-FGC10 cell lines. Adenosine induced arrest in the cell-cycle progression in G0/G1 phase through Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by morphological changes and increased sub-G1 population. Furthermore, increase of ROS, loss of MMP, activation of caspase-3, and down-regulation of Bcl-2 expression was observed. A(1) , A(2a) , A(2b) , and A(3) adenosine receptors mRNA are expressed in the cell lines. Moreover, adenosine-induced apoptosis was inhibited by MRS1220, A(3) adenosine receptor antagonist.

CONCLUSION

Our results suggest that adenosine induced apoptosis in prostate cancer cells via the mitochondrial pathway and is related to the adenosine receptors. These data might suggest that adenosine could be used as an agent for the treatment of prostate cancer.

SiRNA-mediated inhibition of NF-κB p65 down-regulations Bcl-2 expression and promotes apoptosis in hepatocellular carcinoma cell lines

AIM: To investigate the impact of small interfering RNA (siRNA)-mediated inhibition of nuclear factor-κB P65 (NF-κB p65) on Bcl-2 expression and apoptosis in human hepatocellular carcinoma (HCC) cell lines.

METHODS: HCC cell lines HepG2, SMMC7721 and human fetal liver cell line LO2 were used in the study. The expression of NF-κB p65 and Bcl-2 in the above three cell lines was detected by Western blot. SiRNA technology was then used to inhibit NF-κB p65 to observe the effect of NF-κB p65 knockdown on Bcl-2 expression and cell apoptosis.

RESULTS: The expression levels of NF-κB p65 and Bcl-2 in HepG2 and SMMC7721 cells were significantly higher than those in LO2 cells (2.14 ± 0.19, 2.09 ± 0.27 vs 0.54 ± 0.11; 1.42 ± 0.15, 1.47 ± 0.14 vs 0.60 ± 0.08, all P < 0.05). No significant difference was detected in the expression levels of NF-κB p65 and Bcl-2 between HepG2 and SMMC7721 cells. SiRNA transfection significantly down-regulated NF-κB p65 expression in HepG2 and SMMC7721 cells compared to non-transfected cells (2.08 ± 0.19 vs 0.99 ± 0.12; 2.03 ± 0.17 vs 0.94 ± 0.14, both P < 0.05). SiRNA-mediated NF-κB p65 knockdown significantly down-regulated Bcl-2 expression (1.37 ± 0.05 vs 0.72 ± 0.02; 1.44 ± 0.03 vs 0.69 ± 0.03, both P < 0.05) and increased apoptosis (5.12% ± 0.61% vs 37.87% ± 4.10%; 5.80% ± 0.71% vs 40.19% ± 3.78%, both P < 0.05) in HepG2 and SMMC7721 cells compared to non-transfected cells.

CONCLUSION: SiRNA-mediated NF-κB p65 knockdown significantly down-regulates Bcl-2 expression and promotes apoptosis in HepG2 and SMMC7721 cells.