Sustained tumour eradication after induced caspase-3 activation and synchronous tumour apoptosis requires an intact host immune response

Effective anticancer treatments often result in the induction of large amounts of tumour cell death. In vivo, such dying tumour cells are a potential source of antigens for T-cell stimulation. Although apoptosis is generally considered nonimmunogenic, recent evidence suggests that some anticancer therapies that induce apoptosis can elicit antitumour immune responses. Here, a doxycycline-inducible, constitutively active caspase-3 (‘death switch'') was constructed in a murine tumour model to explore the impact of the host immune response to rapid, synchronous and substantial tumour cell apoptosis. In vitro, up to 80% of tumour cells underwent apoptotic cell death within 24 h and death was accompanied by the release of potential ‘danger signal'' molecules HMGB1 and HSP90. In vivo, death switch induction provoked rapid, pronounced tumour regression in immune-competent and immune-deficient mice, but sustained tumour eradication was observed only in immune-competent mice. Moreover, the majority of mice that were tumour free after death switch induction were protected from further tumour rechallenge. In addition, long-term remission after induction of the death switch was completely abrogated following depletion of CD8 T cells. These data suggest that sustained tumour eradication after substantial tumour apoptosis requires an antitumour host immune response that prevents tumour relapse. In many patients, cancer therapies produce encouraging initial responses that are only short lived. These results provide new insights that may have important implications for further development of strategies that result in long-term tumour clearance after initially effective anticancer treatment.     

Chemotherapeutic potential of novel non-toxic nucleoside analogues on EAC ascitic tumour cells

Therapeutic efficacy of nucleoside analogues (NAs) like Gemcitabine, 5-fluorouracil in cancer treatment is already well established. Most of the known NAs are highly toxic to normal cells due to its non-specific action; thus searching for non-toxic NAs are still going on. For that purpose we have synthesised nine different NAs by alteration of their structural and functional groups. The aim of present study is to investigate the therapeutic potential of NAs against mice bearing breast adenocarcinoma cells at IC50 dose for 10 days treatment schedule. Results of the present study showed that, among the seven nucleoside analogues, NA-7 and NA-9 showed maximum therapeutic efficacy in controlling cancer cells by inhibiting cell proliferation and inducing apoptosis without any adverse effects to normal host cells. Additionally, NAs significantly decreased the tumour burden and enhanced survivability of host through generation of reactive oxygen species in tumour cells. These ultimately led to DNA damage, depolarisation of mitochondrial membrane potential and apoptosis in tumour cells. To find out the molecular mechanisms, we showed that administration of NA-7 and NA-9, down- regulating the expression of Bcl-2, cyclin D1, C-myc, P-21 and up-regulating the expression of P-53, Cyt-c, Bax, caspase-3 and caspase-9. The results suggest that NA-7 and NA-9 exhibits significant antitumor activity than 5-fluorouracil by modulating the cell cycle checkpoints and inducing apoptosis in Ehrlich ascites carcinoma (EAC)-bearing mice. Additionally, NA-7 and NA-9 did not show any clastogenic effect on bone marrow cells at sub-lethal dose. Thus, the present study clearly suggested therapeutic benefit of NAs by augmenting anticancer efficacy and diminishing toxicity to the host.     

A novel tumour model system for the study of long-term protective immunity and immune T cell memory

We present a novel non-transgenic system to be used for studies on anti-tumour adoptive immunotherapy (ADI) and long-term T cell memory. Tumour-reactive donor immune cells against lacZ-transfected syngeneic tumour cells (ESbL-Gal) were generated from a naíve T cell repertoire in DBA/2 mice by a well-established priming/restimulation protocol, and transferred to tumour-inoculated athymic nu/nu mice. The donor immune cells efficiently mediated protective anti-tumour immunity involving both CD4(+) and CD8(+) T cells, and anti-metastatic effects were stronger in 4.5 Gy pre-irradiated than in non-irradiated tumour-inoculated hosts. Long-term persistence of beta-galactosidase (Gal)-specific T cells was shown ex vivo by tetramer staining of CD8(+) T cells specific for an immunodominant Gal epitope. Resistance of treated nu/nu mice against tumour rechallenge revealed the existence of long-term protective immune memory.     

Ganoderma atrum polysaccharide induces anti-tumor activity via the mitochondrial apoptotic pathway related to activation of host immune response

Ganoderma atrum polysaccharide (PSG-1), the major active ingredient isolated from Ganoderma atrum, has been suggested as a candidate for cancer therapy. The aim of this study was to investigate the anti-tumor effect of PSG-1 using sarcoma 180 (S-180) transplanted mice and further to examine the molecular mechanisms of PSG-1-induced anti-tumor effect. Results showed that PSG-1 significantly inhibited tumor growth in S-180-bearing mice. PSG-1-induced tumor apoptosis was associated with the alteration of Bcl-2 family proteins, increase of reactive oxygen species generation, loss of mitochondrial membrane potential (Δψ(m) ), release of cytochrome c from the mitochondria into cytosol, and activation of caspase-3 and -9. Elevation of immune function was also shown during PSG-1-induced tumor apoptosis, as evidenced by increase of spleen and thymus indexes, lymphocyte proliferation, concentrations of tumor necrosis factor (TNF)-α, and interleukin-2 in serum. Furthermore, the combined treatment of PSG-1 and cyclophosphamide (CTX) results in an enhancement of the anti-tumor effect of CTX alone via increased host immune response. These results suggested that PSG-1 had a potent anti-tumor activity by induction of tumor apoptosis through mitochondrial pathways, and immunoenhancement effect of PSG-1 was related to its anti-tumor effect. In addition, PSG-1 enhanced CTX-induced anti-tumor activity in S-180-bearing mice.     

Complete tumour regressions induced by vaccination with IL-12 gene-transduced tumour cells in combination with IL-15 in a melanoma model in mice

In the present study, IL-12 gene-transduced B78-H1 melanoma cells (B78/IL-12) were used in combination with IL-15 to treat melanoma-bearing mice. Genetically modified B78/IL-12 cells, when injected subcutaneously, induced strong activation of antitumour mechanisms resulting in complete loss of tumourigenicity. In a therapeutic model, intratumoural injection of irradiated B78/IL-12 cells significantly delayed tumour growth and led to the regression of melanoma in one case. Similarly, consecutive daily injections of IL-15 markedly inhibited tumour progression with occasional curative effects. When used in combination, vaccination with B78/IL-12 cells and treatment with IL-15 caused eradication of established tumours in all treated mice. The combined treatment with B78/IL-12 cells and IL-15 activated not only a local response against tumour, but also induced systemic antitumour immunity that led to a delay or inhibition of tumour development at a distant site. In vitro studies demonstrated that when used together, B78/IL-12 cells and IL-15 induced a shift from a type Th2 to a type Th1 response. Activation of the antitumour immune response in double-treated mice resulted, in part, from stimulation of IFN- production and was accompanied by the development of cytotoxic effectors in the spleen. As shown in a macrophage tumouricidal assay, macrophages could also play a role in the antitumour effects. The results confirmed that vaccination with IL-12 gene-modified tumour cells is superior to the treatment with unmodified tumour cell vaccine and, additionally, showed that IL-15 is an excellent candidate for adjuvant therapy, inducing synergistically not only a delay of tumour growth but also its complete eradication.     

Swainsonine promotes apoptosis in human oesophageal squamous cell carcinoma cells <Emphasis Type="BoldItalic">in vitro</Emphasis> and <Emphasis Type="BoldItalic">in vivo</Emphasis> through activation of mitochondrial pathway

Swainsonine, a natural indolizidine alkaloid, has been reported to have antitumour effects, and can induce apoptosis in human gastric and lung cancer cells. In the present study, we evaluated the antitumour effects of swainsonine on several oesophageal squamous cell carcinoma cells and investigated relative molecular mechanisms. Swainsonine treatment inhibited the growth of Eca-109, TE-1 and TE-10 cells in a concentration-dependent manner as measured by MTT assay. Morphological observation, DNA laddering detection and flow cytometry analysis demonstrated that swainsonine treatment induced Eca-109 cell apoptosis in vitro. Further results showed that swainsonine treatment up-regulated Bax, down-regulated Bcl-2 expression, triggered Bax translocation to mitochondria, destructed mitochondria integrity and activated mitochondria-mediated apoptotic pathway, followed by the release of cytochrome c, which in turn activated caspase-9 and caspase-3, promoted the cleavage of PARP, resulting in Eca-109 cell apoptosis. Moreover, swainsonine treatment inhibited Bcl-2 expression, promoted Bax translocation, cytochrome c release and caspase-3 activation in xenograft tumour cells, resulting in a significant decrease of tumour volume and tumour weight in the swainsonine-treated xenograft mice groups compared with that in the control group. Taken together, this study demonstrated that swainsonine inhibited Eca-109 cells growth through activation of mitochondria-mediated caspase-dependent pathway.     

Tumour escape mechanisms and their therapeutic implications in combination tumour therapy

Most tumours arise from a single normal cell through a sequential evolutionary process of mutation and selection. Tumours are initiated by escaping non‐immune surveillance, which includes defective DNA repair, epigenetic gene alternation, resistance to apoptosis and loss of intercellular contact inhibition. Tumour cells harbour mutations in a number of critical genes that provide selective advantages at various stages during the evolution of the tumour. The tumour cells that circumvent the tumour suppressor mechanisms of the non‐immune surveillance process are edited by the immune system, resulting in the selection of a resistant tumour variant. The selection of the tumour cell is further shaped by its interactions with cells and other factors in its microenvironment. Tumour evolution is thought to adhere to Darwinian principles by escaping both non‐immune (intrinsic) and immune (extrinsic) responses against self‐altered tumour cells. At end‐stage, tumours have escaped both non‐immune and immune surveillance with increased threshold of apoptosis. Combination therapy has been proposed, by exploring the non‐immune and immune suppressive nature of the tumour, and has been found to have a therapeutic efficiency on tumour regression as compared with monotherapies. The combination of immunotherapy and other different modalities, especially vaccines, with conventional anticancer therapies with optimized dosage and scheduling can offer synergistic antitumour effects. Here, we focus on the mechanism of tumour evolution and its implication in combination therapy.     

Caspase-2 as a tumour suppressor

Ever since its discovery 20 years ago, caspase-2 has been enigmatic and its function somewhat controversial. Although many in vitro studies suggested that caspase-2 was important for apoptosis, demonstrating an in vivo cell death role for this caspase has been more problematic, with caspase-2-deficient mice showing limited, tissue-specific cell death defects. Recent results from different laboratories suggest that at least one of its physiological roles in animals is to protect against cellular stress and transformation. As such, loss of caspase-2 augments tumorigenesis in some mouse models of cancer, assigning a tumour suppressor function to this enigmatic caspase. This review focuses on this seemingly non-apoptotic function of caspase-2 as a tumour suppressor and reconciles some of the recent findings in the field.     

Cold-induced changes in brown adipose tissue thermogenic capacity of immunocompetent and immunodeficient hairless mice

Mild cold acclimation (22°C, 3 weeks) of hairless mice was shown to increase 5-fold the brown adipose tissue uncoupling protein content in immunodeficient BALB/c nu/nu mice, but by only 2.3-fold in immunocompetent BFU mice. The difference in activation of brown adipose tissue thermogenic capacity was due to a 2-fold increase in the content of brown adipose tissue in nu/nu mice only, which was paralleled by an increase in brown adipose tissue protein but not DNA content. Likewise, only in nu/nu mice the cold acclimation increased the reaction of natural killer cells in blood and peritoneal exudate with a shift from spleen to lymph nodes and increased the phagocytic index. The results indicate that the immune system may influence the defence against cold at the level of brown adipose tissue thermogenesis.Abbreviations AU arbitrary unit(s) - bw body weight - HEMA 2-hydromethyl-metacrylate copolymer - BAT brown adipose tissue - UCP uncoupling protein - ATPase mitochondrial F_oF₁-ATPsynthase - IL-1 interleukin 1 - TNF tumour necrosis factor - NK cells natural killer cells - T _a ambient temperature     

Anti-neoplastic action of aspirin against a T-cell lymphoma involves an alteration in the tumour microenvironment and regulation of tumour cell survival

The present study explores the potential of the anti-neoplastic action of aspirin in a transplantable murine tumour model of a spontaneously originated T-cell lymphoma designated as Dalton's lymphoma. The antitumour action of aspirin administered to tumour-bearing mice through oral and/or intraperitoneal (intratumoral) routes was measured via estimation of survival of tumour-bearing mice, tumour cell viability, tumour progression and changes in the tumour microenvironment. Intratumour administration of aspirin examined to assess its therapeutic potential resulted in retardation of tumour progression in tumour-bearing mice. Oral administration of aspirin to mice as a prophylactic measure prior to tumour transplantation further primed the anti-neoplastic action of aspirin administered at the tumour site. The anti-neoplastic action of aspirin was associated with a decline in tumour cell survival, augmented induction of apoptosis and nuclear shrinkage. Tumour cells of aspirin-treated mice were found arrested in G0/G1 phase of the cell cycle and showed nuclear localization of cyclin B1. Intratumoral administration of aspirin was accompanied by alterations in the biophysical, biochemical and immunological composition of the tumour microenvironment with respect to pH, level of dissolved O2, glucose, lactate, nitric oxide, IFNγ (interferon γ), IL-4 (interleukin-4), IL-6 and IL-10, whereas the TGF-β (tumour growth factor-β) level was unaltered. Tumour cells obtained from aspirin-treated tumour-bearing mice demonstrated an altered expression of pH regulators monocarboxylate transporter-1 and V-ATPase along with alteration in the level of cell survival regulatory molecules such as survivin, vascular endothelial growth factor, heat-shock protein 70, glucose transporter-1, SOCS-5 (suppressor of cytokine signalling-5), HIF-1α (hypoxia-inducible factor-1α) and PUMA (p53 up-regulated modulator of apoptosis). The study demonstrates a possible indirect involvement of the tumour microenvironment in addition to a direct but limited anti-neoplastic action of aspirin in the retardation of tumour growth.     

瞬时受体电位香草酸亚型1激活释放的P物质在小鼠急性心肌梗死后凋亡中的保护作用

瞬时受体电位香草酸亚型1 (transient receptor potential vanilloid 1, TRPV1)在心肌缺血激活后可传导心绞痛信号和释放P物质(substance P, SP).SP是速激肽家族成员之一,主要通过结合并激活神经激肽1 (neurokinin 1,NK1)受体发挥作用. TRPV1和SP在缺血性心脏病中对心功能的恢复和重塑有一定保护作用,但对心肌梗死后凋亡的作用及具体机制尚不明确.本研究用TRPV1基因敲除(TRPV1-/- )小鼠和野生型(wide type, WT)小鼠建立心肌梗死模型,并外源性给予SP和NK1受体拮抗剂RP67580,用TTC染色法观察梗死的面积,TUNEL法检测心肌细胞凋亡指数,Western印迹方法检测caspase-3、Bcl-2、Bax、p53的蛋白表达.结果发现,心肌梗死24 h后,TRPV1-/-小鼠比WT小鼠梗死面积更大,凋亡指数和caspase-3活性更高,Bcl-2/Bax和p53蛋白表达更低. SP预处理可以明显缩小TRPV1-/-小鼠梗死面积,降低凋亡指数、caspase-3活性和升高Bcl-2/Bax比值,而在WT小鼠中改善不明显.外源性给予RP67580,阻断SP与NK1受体结合后,与相应对照组相比,WT小鼠梗死面积和凋亡指数更大,caspase-3蛋白表达更高,Bcl-2/Bax比值更低;TRPV1-/-小鼠与相应对照组比较,凋亡指数和caspase-3表达升高,Bcl-2/Bax比值降低.研究结果表明,SP可能介导了TRPV1在急性心肌梗死后凋亡中的保护作用.     

Linoleic Acid Derivative DCP-LA Protects Neurons from Oxidative Stress-Induced Apoptosis by Inhibiting Caspase-3/-9 Activation

The present study aimed at understanding the effect of the linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) on oxidative stress-induced neuronal death. Sodium nitroprusside (SNP; 1 mM) reduced viability of cultured rat cerebral cortical neurons to 50% of basal levels, but DCP-LA significantly prevented the SNP effect in a concentration (1–100 nM)-dependent manner. In addition, DCP-LA (100 nM) rescued neurons from SNP-induced degradation. SNP (1 mM) activated caspase-3 and -9 in cultured rat cerebral cortical neurons, but DCP-LA (100 nM) abolished the caspase activation. For a mouse model of middle cerebral artery occlusion, oral administration with DCP-LA (1 mg/kg) significantly diminished degraded area due to cerebral infarction. The results of the present study, thus, demonstrate that DCP-LA protects neurons at least in part from oxidative stress-induced apoptosis by inhibiting activation of caspase-3/-9.     

Ivermectin suppresses tumour growth and metastasis through degradation of PAK1 in oesophageal squamous cell carcinoma

Oesophageal squamous cell carcinoma (ESCC), the most common form of oesophageal malignancies in the Asia‐Pacific region, remains a major clinical challenge. In this study, we found that ivermectin, an effective antiparasitic drug that has been approved for patients to orally treat onchocerciasis for over 30 years, displayed potent antitumour activity against ESCC cells in vitro and in nude mice. We demonstrated that ivermectin significantly inhibited cell viability and colony formation, and induced apoptosis through a mitochondrial‐dependent manner in ESCC cells. Ivermectin also abrogated ESCC cell migration, invasion, as well as the protein levels of MMP‐2 and MMP‐9. Mechanistically, ivermectin strongly inhibited the expression of PAK1; by further gain‐ and loss‐of‐function experiments, we confirmed that PAK1 played a crucial role in ivermectin‐mediated inhibitory effects on ESCC cells. In addition, the data indicated that ivermectin promoted PAK1 degradation through the proteasome‐dependent pathway. Additionally, ivermectin synergized with chemotherapeutic drugs including cisplatin and 5‐fluorouracil to induce apoptosis of ESCC cells. Interestingly, the in vivo experiments also confirmed that ivermectin effectively suppressed tumour growth and lung metastasis of ESCC. Collectively, these results indicate that ivermectin exerts a potent antitumour activity against ESCC and is a promising therapeutic candidate drug for ESCC patients, even those carrying metastasis.     

On the mechanism of alkylphosphocholine (APC)-induced apoptosis in tumour cells

Alkylphosphocholines (APCs) represent a new and very encouraging class of antitumour agents that have also been shown to induce apoptosis in tumour cells, but their exact mode of action has still not been elucidated. The APC compound presented here, S-1-O-phosphocholine-2- N-acetyl-octadecane (S-NC-2) induces apoptosis in a variety of cancer cells. To define the molecular requirements for S-NC-2-induced apoptosis, activation of caspase-8 and -3 and the cleavage of death substrates, such as poly(ADP-ribose) polymerase (PARP), were investigated in Jurkat, BJAB, SKW6.4 and K562 cells. The signalling pathway seems to be initiated at the death receptor level. Cells that are defective in Fas-receptor signalling (e.g., FADDdn BJAB), as well as cells lacking the Fas receptor (K562), were resistant to S-NC-2 treatment. Furthermore, the treatment of Jurkat cells with S-NC-2 resulted in the clustering of death receptor molecules and co-localisation of the Fas receptor with caveolin, a marker for lipid rafts. In addition, the involvement of mitochondria was detected, since S-NC-2 induces the breakdown of the mitochondrial membrane potential. Overexpression of the anti-apoptotic protein Bcl-2 prevented the loss of delta psi(m) in type II (Jurkat) but not in type I cells (SKW6.4). Moreover, cleavage of Bid was found, which points to a possible linkage between the receptor-dependent and the mitochondrial pathways.     

Individual caspase-10 isoforms play distinct and opposing roles in the initiation of death receptor-mediated tumour cell apoptosis

The cysteine protease caspase-8 is an essential executioner of the death receptor (DR) apoptotic pathway. The physiological function of its homologue caspase-10 remains poorly understood, and the ability of caspase-10 to substitute for caspase-8 in the DR apoptotic pathway is still controversial. Here, we analysed the particular contribution of caspase-10 isoforms to DR-mediated apoptosis in neuroblastoma (NB) cells characterised by their resistance to DR signalling. Silencing of caspase-8 in tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-sensitive NB cells resulted in complete resistance to TRAIL, which could be reverted by overexpression of caspase-10A or -10D. Overexpression experiments in various caspase-8-expressing tumour cells also demonstrated that caspase-10A and -10D isoforms strongly increased TRAIL and FasL sensitivity, whereas caspase-10B or -10G had no effect or were weakly anti-apoptotic. Further investigations revealed that the unique C-terminal end of caspase-10B was responsible for its degradation by the ubiquitin–proteasome pathway and for its lack of pro-apoptotic activity compared with caspase-10A and -10D. These data highlight in several tumour cell types, a differential pro- or anti-apoptotic role for the distinct caspase-10 isoforms in DR signalling, which may be relevant for fine tuning of apoptosis initiation.     

Cell kinetic studies of endothelial cells in the adenocarcinoma EO 771 and the effect of cyclophosphamide.

Cell kinetic studies of endothelial cells in the adenocarcinoma EO 771 growing in C57bl/6j mice and after transplantation into Balb/c-nu/nu mice, as well as of the effect of cyclophosphamide treatment have been carried out. The 3H-thymidine labelling index of endothelial cells decreases from about 8% 3-6 days after tumour inoculation to about 3% at 18 days. This decrease parallels that of the labelling index of tumour cells, i.e. there is a positive correlation between the labelling index of endothelial cells and that of tumour cells. The labelling index of endothelial cells in the tumour periphery is two to three times as high as that in the tumour centre reflecting corresponding differences in the rate of proliferation. There is no difference in the proliferation of endothelial cells whether the tumour grows in C57bl/6j or in Balb/c-nu/nu mice. After treatment with cyclophosphamide the labelling index of endothelial cells decreases within 2 days to 1-2% and remains that low despite regrowth of the tumour with increased tumour cell proliferation, indicating that tumour relapse does not depend on tumour angiogenesis.     

Growth factors prevent changes in Bcl-2 and Bax expression and neuronal apoptosis induced by nitric oxide

Recent studies have shown that nitric oxide (NO) donors can trigger apoptosis of neurons, and growth factors such as insulin-like growth factor-1 (IGF-1) and basic fibroblast growth factor (bFGF) can protect against NO-induced neuronal cell death. The purpose of this study was to elucidate the possible mechanisms of NO-mediated neuronal apoptosis and the neuroprotective action of these growth factors. Both IGF-1 and bFGF prevented apoptosis induced by NO donors, sodium nitroprusside (SNP) or 3-morpholinosydnonimin (SIN-1) in hippocampal neuronal cultures. Incubation of neurons with SNP induced caspase-3-like activation following downregulation of Bcl-2 and upregulation of Bax protein levels in cultured neurons. Treatment of neurons with a bax antisense oligonucleotide inhibited the caspase-3-like activation and neuronal death induced by SNP. In addition, treatment of neurons with an inhibitor of caspase-3, Ac-DEVD-CHO, together with SNP did not affect the changes in the protein levels, although it inhibited NO-induced cell death. Pretreatment of cultures with either IGF-1 or bFGF prior to NO exposure inhibited caspase-3-like activation together with the changes in Bcl-2 and Bax protein levels. These results suggest that the changes in Bcl-2 and Bax protein levels followed by caspase-3-like activation are a component in the cascade of NO-induced neuronal apoptosis, and that the neuroprotective actions of IGF-1 and bFGF might be due to inhibition of the changes in the protein levels of the Bcl-2 family.     

Extrathymic clonal deletion of self-reactive cells in athymic mice

The repertoire of T cells present in congenitally athymic mice was studied by flow cytometric analysis on populations of T cells expanded polyclonally in vitro. Athymic (BALB/c x C57BL/6)F1 mice have levels of potentially autoreactive V beta 3- and V beta 11-bearing T cells that are significantly higher than those of euthymic CB6F1 mice. Examination of potentially autoreactive cells in athymic AKR mice, however, yielded contrasting results. V beta 6+ cells, which are deleted intrathymically in normal AKR mice, are present in the repertoire of young (less than 6-wk-old) AKR nu/nu mice. Isolation of a cloned CD4+V beta 6+ cell line with Mls-1a reactivity from young AKR nu/nu mice indicates that the correlation between TCR usage and specificity is consistent with that described in euthymic mice and that this population contains autoreactive T cells that are not anergic. By 6 mo of age, however, cells expressing V beta 6 are no longer detectable. Inability to detect these cells is not simply caused by failure to expand these cells in culture, because freshly isolated populations from old nude mice exhibit the same selective absence of V beta 6-bearing cells. The data strongly suggest that extrathymic deletion, rather than clonal anergy, accounts for the apparent absence of autoreactive V beta 6-bearing cells in aged AKR nu/nu mice.     

NF-kB 拮抗剂PDTC 对HepG2 细胞的抑制及对caspase-3 表达的影响

目的:研究NF-kB拮抗剂PDTC诱导人肝癌HepG2细胞凋亡及其对凋亡相关基因caspase-3表达的影响,初步探讨其诱导凋亡的可能机制。方法:以不同浓度的PDTC处理人肝癌HepG2细胞,利用MTT法检测对人肝癌HepG2细胞凋亡的影响;利用RT-PCR和Western-blot检测caspase-3mRNA和蛋白的表达。结果:不同浓度PDTC作用人肝癌HepG2细胞不同时间后,能够显著抑制HepG2细胞的生长增殖,存在剂量和时间依赖性(P<0.05);PDTC能够上调HepG2细胞中caspase-3mRNA和蛋白的表达。结论:NF-kB拮抗剂PDTC对人肝癌HepG2细胞产生显著抑制,并能上调HepG2细胞中caspase-3mRNA和蛋白的表达。