Bisphenol A induced male germ cell apoptosis via IFNß-XAF1-XIAP pathway in adult mice.

Bisphenol A (BPA) impairs male fertility by acting as an endocrine disruptor. However, the mechanisms by which BPA cause reproductive toxicity are not fully elucidated. Here, we explored the role of XAF1, a novel pro-apoptosis molecule, in BPA-induced abnormal spermatogenesis and the transcriptional regulation mechanism of BPA-induced XAF1. BPA exposure detrimentally impacted spermatogenesis by inducing excessive germ cell apoptosis. XAF1 was upregulated in germ cells after BPA exposure, which was involved in the apoptosis pathway. In addition, the expression levels of XIAP and XAF1 were inversely correlated after BPA exposure. Knockdown of XAF1 expression partially inhibited the apoptosis of GC-2 cells, suppressed the activation of caspase 3 and improved the BPA-induced XIAP expression. Moreover, IFNß expression levels were significantly upregulated after BPA exposure both in vitro and in vivo, and these levels were positively related to the expression of XAF1. Furthermore, IFNß knockdown reduced the expression of XAF1 and increased the expression of XIAP in BPA-treated GC-2 cells. Together, these data indicated that BPA triggers male germ cell apoptosis in mice via the IFNß-XAF1-XIAP pathway, which may contribute to BPA-induced testis toxicity.

Artepillin C as a targeting survivin molecule in oral squamous cell carcinoma cells in vitro: A preliminary study.

BACKGROUND: Survivin, a member of the inhibitor of apoptosis family, is overexpressed in most human tumors, but undetectable in normal adult tissues. It is a promising target molecule in cancer treatment, as interference in its function promotes apoptosis. Artepillin C, a major, biologically active ingredient of Brazilian propolis, possesses anticancer activity against several cancer cells with different tissue origins. However, little is known about its bioactivity on oral squamous cell carcinoma cells or its effect on survivin expression. The aim of this study was to investigate the cytotoxic and antisurvivin activities of artepillin C in oral squamous cell carcinoma cells. METHODS: HSC-3 human oral squamous cell carcinoma cells were treated with varying doses of artepillin C for up to 72 hours. Cell viability was measured by WST-1, and the cytotoxic effects of artepillin C on HSC-3 cells were quantified with flow cytometry. The survivin levels were determined by ELISA. RESULTS: Artepillin C exhibited dose- and time-dependent cytotoxic effects on HSC-3 cells. Flow cytometric analysis showed that 22% of untreated HSC-3 cells underwent spontaneous cell death, whereas 77.32% of the cells were killed in response to the highest dose of artepillin C at 72 hours. Survivin expression was reduced in treated cells. CONCLUSIONS: HSC-3 cells are vulnerable to artepillin C in a dose- and time-dependent manner. HSC-3 cell death induced by artepillin C, at least in part, was a result of a decrease in survivin levels.

Inhibition of survivin expression after using oxaliplatin and vinflunine to induce cytogenetic damage in vitro in lymphocytes from colon cancer patients and healthy individuals.

Chemotherapy drugs usually inflict a lethal dose to tumour cells with the consequence that these cells are being killed by cell death. However, each round of chemotherapy also causes damage to normal somatic cells. The DNA cross-linking agent oxaliplatin (OXP), which causes DNA double-strand breaks, and vinflunine (VFN), which disrupts the mitotic spindle, are two of these chemotherapy drugs which were evaluated in vitro using peripheral lymphocytes from colorectal cancer patients and healthy individuals to determine any differential response. Endpoints examined included micronucleus (MN) induction using the cytokinesis-blocked micronucleus (CBMN) assay and pancentromeric fluorescence in situ hybridisation. Also, survivin expression was monitored since it regulates the mitotic spindle checkpoint and inhibits apoptosis. OXP produced cytogenetic damage (micronuclei in binucleated cells) via its clastogenic but also previously unknown aneugenic action, possibly through interfering with topoisomerase II, whilst VFN produced micronuclei in mononucleated cells because of incomplete karyokinesis. Survivin expression was found to be significantly reduced in a concentration-dependent manner by not only OXP but surprisingly also VFN. This resulted in large numbers of multinucleated cells found with the CBMN assay. As survivin is upregulated in cancers, eliminating apoptosis inhibition might provide a more targeted chemotherapy approach; particularly, when considering VFN, which only affects cycling cells by inhibiting their mitotic spindle, and alongside possibly other pro-apoptotic compounds. Hence, these newly found properties of VFN -the inhibition of survivin expression-might demonstrate a promising chemotherapeutic approach as VFN induces less DNA damage in normal somatic cells compared to other chemotherapeutic compounds.

Survivin, a molecular target for therapeutic interventions in squamous cell carcinoma.

Squamous cell carcinoma (SCC) is the most common cancer worldwide. The treatment of locally advanced disease generally requires various combinations of radiotherapy, surgery, and systemic therapy. Despite aggressive multimodal treatment, most of the patients relapse. Identification of molecules that sustain cancer cell growth and survival has made molecular targeting a feasible therapeutic strategy. Survivin is a member of the Inhibitor of Apoptosis Protein (IAP) family, which is overexpressed in most of the malignancies including SCC and totally absent in most of the normal tissues. This feature makes survivin an ideal target for cancer therapy. It orchestrates several important mechanisms to support cancer cell survival including inhibition of apoptosis and regulation of cell division. Overexpression of survivin in tumors is also associated with poor prognosis, aggressive tumor behavior, resistance to therapy, and high tumor recurrence. Various strategies have been developed to target survivin expression in cancer cells, and their effects on apoptosis induction and tumor growth attenuation have been demonstrated. In this review, we discuss recent advances in therapeutic potential of survivin in cancer treatment.

Anticancer activity of a trans-platinum(II) complex of 3-aminoflavone to ovarian cancer cells.

OBJECTIVES: Cisplatin is a classical anticancer drug used in the treatment of ovarian cancer. Unfortunately, the treatment is associated with numerous adverse effects. Studies concerning new platinum derivatives with less organ toxicity are conducted. The aim of this study was to analyse the effect of a new trans-platinum(II) complex of 3-aminoflavone on the viability and mortality of the cells from OVCAR 3 and CAOV 3 ovarian cancer cell lines and on the expression of the selected genes involved in the process of apoptosis. MATERIAL AND METHODS: The viability of ovarian cancer cells and the cytotoxicity of a trans-platinum(II) complex of 3-amino-flavone: [trans-Pt(3-af )2Cl2), trans-bis-(3-aminoflavone) dichloridoplatinum(II)] and cisplatin were analysed using a spectrophotometric method with the use of MTT assay and LDH assay. BAX, BCL2, BIRC5 gene expression analysis on mRNA level was conducted with the use of Real-Time PCR method. RESULTS: It was observed that parallel to an increase in the concentration of the new complex compound and cisplatin there is a decrease in viability and an increase in mortality of ovarian cancer cells. As a result of exposure to the studied compound and cisplatin, an increased BAX gene expression and decreased BCL2 and BIRC5 gene expression were observed in the studied ovarian cancer cell lines. CONCLUSION: Trans-Pt(3-af )2Cl2 exhibits anticancer activity towards OVCAR 3 and CAOV 3 ovarian cancer cell lines. The studied complex compound can be considered as a potential anticancer drug.

Survivin-targeted nanoparticles for pancreatic tumor imaging in mouse model.

We investigated the potential of targeting survivin, an inhibitor of apoptosis, in visualize pancreatic tumor in mouse model using targeted magnetic nanoparticles (MNPs) and magnetic resonance imaging (MRI). Chitosan-coated MNPS and survivin antisense oligonucleotide(ASON) were conjugated to give Sur-MNPs. Accumulations of targeted, non-targeted nanoparticles or nonsense oligonucleotide-MNPs (NSON-MNPs) in the liver, spleen, kidney and tumors were determined. Targeted nanoparticles were highly accumulated in BxPC-3 cells but not in non-cancer cells. In vivo MRI showed a significant T2 signal reduction in tumors of mice injected with targeted nanoparticles but slight signal change in tumors of mice injected with non-targeted nanoparticles or NSON-MNPs. Prussian blue staining demonstrated highly accumulated Sur-MNPs in tumor mass compared with normal pancreatic, kidney and liver tissues. Our data show that the MNPs functionalized with ASON lead to the targeted localization in pancreatic tumors. Survivin targeted nanoparticles could be used for detection of pancreatic tumors.

[Effect of DJ-1 silencing by RNA interference on growth of xenografted human laryngeal squamous cell carcinoma Hep-2 cells in nude mice].

Objective: To investigate the effect of silencing DJ-1 on xenografted human laryngeal squamous cell carcinoma (LSCC) Hep-2 cells in nude mice. Methods: Xenograft model of human LSCC was established by subcutaneous transplantation of Hep-2 cells in 24 nude mice. The LSCC-bearing nude mice were randomly divided into 3 groups (n=8 in each):DJ-1 siRNA low dose group and DJ-1 siRNA high dose group were injected in tumors with 20 µg of DJ-1 siRNA or 40 µg of DJ-1 siRNA in 50 µL, respectively; control group was injected with 5% glucose solution in 50 µL, twice a week for 3 weeks. The weight and size of tumors were measured before injection. The animals were sacrificed 48 h after the final treatment, and the tumors were harvested and weighed. The apoptosis and proliferation of tumor cells were determined; the expressions of Caspase-3 and Ki-67 in tumor specimens were detected with immunohistochemistry. The expression of DJ-1, PTEN, survivin mRNA and protein in tumor tissues were detected by RT-PCR and Western blotting, respectively. Results: Tumor weight in low dose group[(0.66±0.15)g] and high dose group[(0.48±0.11)g] were significantly lower than that in control group[(0.83±0.16)g, all P<0.05]. The inhibition rates of low dose group and high dose group were (20.48±0.18)% and (42.16±0.13)%, respectively. Immunohistochemistry showed that the expression of Caspase-3 was increased and Ki-67 was reduced in tumor specimens, compared with the control group (all P<0.05). RT-PCR and Western blot results showed that in low dose group and high dose group the mRNA and protein expression of DJ-1 and survivin significantly decreased (all P<0.05), while PTEN mRNA and protein content increased (all P<0.05). Conclusion: High dose DJ-1 siRNA can inhibit the tumor growth in human LSCC xenograft nude mouse model, which indicates that down-regulating DJ-1 and survivin, and up-regulating PTEN expression may lead to blockage of PI3K-PKB/Akt signaling pathway and promoting tumor cell apoptosis.

DHT inhibits the Aß25-35-induced apoptosis by regulation of seladin-1, survivin, XIAP, bax, and bcl-xl expression through a rapid PI3-K/Akt signaling in C6 glial cell lines.

Previous evidences indicate that androgen is neuroprotective in the brain. However, the underling mechanisms remain to be fully elucidated. Moreover, it is controversial whether dihydrotestosterone (DHT) modulates the expression of apoptosis-related effectors, such as survivin, XIAP, bax, and bcl-xl proteins mediated by the PI3-K/Akt pathway, which contributes to androgen neuroprotection. In this study using a C6 glial cell model, apoptotic cells were detected by flow cytometry. Akt, seladin-1, survivin, XIAP, bcl-xl, and bax protein expression is investigated by Western blot. After amyloid ß-protein fragment (Aß25-35) treatment, apoptotic cells at early (annexin V+, PI-) and late (annexin V+, PI+) stages were significantly increased. Apoptosis at early and late was obviously inhibited in the presence of DHT. The effect of DHT was markedly blocked by PI3-K inhibitor LY294002.To elicit the mechanism of DHT protection, the expression of seladin-1, survivin, XIAP, bax, and bcl-xl protein was determined in C6 cells treated with Aß25-35, DHT, or LY294002. Aß25-35 significantly downregulated the expression of seladin-1, survivin, XIAP, bcl-xl protein and upregulated the expression of bax protein. DHT significantly inhibited the expression of bax, seladin-1, survivin, XIAP, and bcl-xl protein induced by Aß25-35. Further, we found the effect of DHT was significantly inhibited by LY294002. Collectively, in a C6 glial cell model, we firstly found that DHT inhibits Aß25-35-induced apoptosis by a rapid nongenic PI-3K/Akt activation as well as regulation of seladin-1, survivin, XIAP, bcl-xl, and bax proteins.

Berberine and Curcumin Target Survivin and STAT3 in Gastric Cancer Cells and Synergize Actions of Standard Chemotherapeutic 5-Fluorouracil.

Aberrantly expressed survivin and STAT3 signaling have emerged as major determinants of chemoresistance in gastric cancer. We evaluated effects of potent herbal derivatives curcumin, berberine, and quercetin on STAT3 signaling, survivin expression, and response to 5-fluorouracil (5-FU) treatment in gastric cancer cells (AGS). Cytotoxic and inhibitory effects of berberine, curcumin, and quercetin alone or in combination with 5-FU were examined by MTT assay, and their effect on survivin, STAT3, and the phosphorylated active STAT3 (pSTAT3) expression was examined by western blotting. Effect of these herbal derivatives on STAT3 DNA binding activity was measured by electrophoretic mobility shift assay. Curcumin, berberine, and quercetin effectively downregulated pSTAT3 levels, survivin expression, and gastric cancer cells viability in a dose-dependent manner (with corresponding IC50 values of 40.3µM, 29.2µM and 37.5µM, respectively). Berberine was more effective in inhibiting survivin expression as compared to other herbal agents. 5-FU in combination with berberine or curcumin showed a synergistic inhibition of survivin and STAT3 level resulting in enhanced cell death in gastric cancer cells. Overall, our data suggest use of berberine and curcumin as adjunct therapeutics to overcome chemoresistance during treatment of gastric malignancies.

Silibinin induced the apoptosis of Hep-2 cells via oxidative stress and down-regulating survivin expression.

Silibinin is an anticancer and chemopreventive natural compound, which is extracted from milk thistle (Silybum marianum). It is reported that silibinin has anticancer efficacy in many malignant tumors. Laryngeal carcinoma is the second most common head and neck squamous carcinoma. In the present work, we investigated the effects of silibinin on laryngeal squamous cell carcinoma (LSCC) cell line Hep-2 cells. We found that silibinin induced the decrease of cell viability in Hep-2 cells with a concentration- and time-dependent manner. Moreover, silibinin resulted in the apoptosis of Hep-2 cells and had synergy effects with arsenic trioxide. Intracellular reactive oxygen species (ROS) accumulation increased because of silibinin exposure. ROS scavenger NAC alleviated the cytotoxicity of silibinin to Hep-2 cells. The mitochondrial membrane potential (MMP) was lost in Hep-2 cells treated with silibinin. Subsequently, silibinin induced the activation of caspase-3 in Hep-2 cells and caspase inhibitor Z-VAD-FMK inhibited the cytotoxicity of silibinin in Hep-2 cells. The survivin expression decreased after Hep-2 cells were treated with silibinin. In conclusion, silibinin induced the apoptosis of Hep-2 cells via oxidative stress and down-regulating survivin expression. Therefore, silibinin is a potential therapeutical agent against LSCC in future.

Induction of prosurvival molecules during treatment: rethinking therapy options for photodynamic therapy.

Photodynamic therapy (PDT) not only causes direct cytotoxicity to malignant cells within a tumor but also appears to have both direct and indirect effects on nonmalignant components of the tumor microenvironment. A host of preclinical studies have been performed to document how PDT modulates the tumor microenvironment. This article explores the role of cellular components such as the hypoxia-inducible factor 1α, vascular endothelial growth factor, cyclooxygenase-2, matrix metalloproteinases, the antiapoptotic protein survivin, and 17-AAG (an inhibitor of heat shock proteins), with the hope that combined modality regimens targeting these processes may improve PDT tumor responsiveness.

Apoptotic effect of Polygonum Cuspidatum in oral cancer cells through the regulation of specificity protein 1.

OBJECTIVES: The aim of this study was to evaluate the growth inhibitory and apoptosis-inducing effects and mechanisms of Polygonum cuspidatum root in oral cancer cells. MATERIALS AND METHODS: The testing materials were separated by normal-phase silica gel liquid chromatography. The effect of P. cuspidatum root on apoptotsis and its mechanism were performed using 3-(4,5-dimethylthiazol-20yl)-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium) (MTS) assay, western blot analysis, RT-PCR, promoter assay, and (4'-6-Diamidino-2-phenylindole) (DAPI) staining. RESULTS: The methanol extract of P. cuspidatum (MEPC) inhibited the proliferation of oral cancer cells by inducing caspase-dependent apoptosis. Protein and mRNA expression levels and the transactivation of Specificity protein 1 (Sp1) were markedly decreased in KB cells treated with MEPC. Ethyl acetate fraction (EA) from MEPC was more potent than aqueous fraction (AQ) from MEPC to induce apoptosis. F2, F3, and F4 from EA differentially inhibited the growth of KB cells, and it depends on the amount of Emodin in F2, F3, and F4. Moreover, Emodin inhibited oral cancer cell growth and induced caspase-dependent apoptosis by decreasing Sp1. MEPC also decreased an apoptosis-related downstream target of Sp1 protein, survivin. CONCLUSION: The results from this study strongly suggest that MEPC, its fraction, and Emodin may be potential bioactive materials to cause apoptosis mechanism via the down-regulation of Sp1 in oral cancer cells.

Molecularly targeted radiosensitization of human prostate cancer by modulating inhibitor of apoptosis.

PURPOSE: The inhibitor of apoptosis proteins (IAP) are overexpressed in hormone-refractory prostate cancer, rendering the cancer cells resistant to radiation. This study aims to investigate the radiosensitizing effect of small-molecule IAP inhibitor both in vitro and in vivo in androgen-independent prostate cancer and the possible mechanism of radiosensitization. EXPERIMENTAL DESIGN: Radiosensitization of SH-130 in human prostate cancer DU-145 cells was determined by clonogenic survival assay. Combination effect of SH-130 and ionizing radiation was evaluated by apoptosis assays. Pull-down and immunoprecipitation assays were employed to investigate the interaction between SH-130 and IAPs. DU-145 xenografts in nude mice were treated with SH-130, radiation, or combination, and tumor suppression effect was determined by caliper measurement or bioluminescence imaging. Nuclear factor-kappaB activation was detected by luciferase reporter assay and quantitative real-time PCR. RESULTS: SH-130 potently enhanced radiation-induced caspase activation and apoptosis in DU-145 cells. Both X-linked IAP and cIAP-1 can be pulled down by SH-130 but not by inactive SH-123. Moreover, SH-130 interrupted interaction between X-linked IAP/cIAP-1 and Smac. In a nude mouse xenograft model, SH-130 potently sensitized the DU-145 tumors to X-ray radiation without increasing systemic toxicity. The combination therapy suppressed tumor growth more significantly than either treatment alone, with over 80% of complete tumor regression. Furthermore, SH-130 partially blocked tumor necrosis factor-alpha- and radiation-induced nuclear factor-kappaB activation in DU-145 cells. CONCLUSIONS: Our results show that small-molecule inhibitors of IAPs can overcome apoptosis resistance and radiosensitize human prostate cancer with high levels of IAPs. Molecular modulation of IAPs may improve the outcome of prostate cancer radiotherapy.

Inhibition of PHF-like tau hyperphosphorylation in SH-SY5Y cells and rat brain slices by K252a.

Abnormal hyperphosphorylation of tau is believed to constitute a critical biochemical event in the process of neurofibrillary degeneration of Alzheimer's disease. We have developed a cellular model where apparently authentic PHF-like tau hyperphosphorylation is induced by okadaic acid. To gain deeper insight into the complex mechanisms of this pathological process we tested a variety of kinase inhibitors in this model. We found that K252a is differentiated from staurosporine by its inhibition of ERK2: both compounds are structurally related microbial metabolites generally believed to have only moderate kinase selectivity. However, since ERK2 inhibitors are exceedingly rare, we used this differential inhibitory property of K252a to demonstrate the involvement of ERK2 in PHF-type tau hyperphosphorylation. K252a was uniquely able to completely suppress the okadaic acid-induced tau hyperphosphorylation in SH-SY5Y cells and rat brain slices by way of including ERK2 in its inhibitory spectrum, and to conserve the normal binding of tau to tubulin. GSK3 inhibitors partially affected the normal state of tau phosphorylation in SH-SY5Y cells, but had no impact on okadaic acid-induced tau hyperhosphorylation. As K252a is the first molecule identified capable of preventing the spectrum of PHF-like tau hyperphosphorylation markers, it may represent a conceptual starting point for therapeutic development of suitable spectrum kinase inhibitors.

Livin/ML-IAP as a new target for cancer treatment.

Livin is a member of the inhibitors of apoptosis protein (IAP) gene family, which encodes negative regulatory proteins that prevent cell apoptosis. Livin is selectively expressed in the most common human neoplasms and appears to be involved in tumor cell resistance to chemotherapeutic agents. Several studies in vitro and in vivo have demonstrated that down-regulation of Livin expression increases the apoptotic rate, reduces tumor growth potential and sensitized tumor cells to chemotherapeutic drugs. This review will focus on the role of this protein during cancer development and progression and will demonstrate possible targets for cancer therapy.

Effect of combining epidermal growth factor receptor inhibitors and cisplatin on proliferation and apoptosis of oral squamous cell carcinoma cells.

Epidermal growth factor (EGF) is known to be involved in the proliferation and metastasis of squamous cell carcinoma (SCC), suggesting that the EGF receptor (EGFR) must also contribute to SCC development. In combination with conventional anti-cancer drugs, agents that block EGFR may represent an efficient means of inhibiting proliferation and inducing apoptosis in SCC cells. We investigated the effects of combining an anti-EGFR monoclonal antibody (C225) or an EGFR-selective tyrosine kinase inhibitor (AG1478) with the conventional anti-cancer drug cisplatin on the oral SCC (OSCC) cell lines NA and Ca9-22. We detected constitutive expression of EGFR on the cell membranes of both cell lines. OSCC cell proliferation was inhibited by C225, AG1478 and cisplatin in a dose-dependent manner. The combination of C225 or AG1478 with cisplatin at concentrations

5-Aminolevulinic acid-based photodynamic therapy suppressed survival factors and activated proteases for apoptosis in human glioblastoma U87MG cells.

Glioblastoma is the most common astrocytic brain tumor in humans. Current therapies for this malignancy are mostly ineffective. Photodynamic therapy (PDT), an exciting treatment strategy based on activation of a photosensitizer, has not yet been extensively explored for treating glioblastoma. We used 5-aminolevulinic acid (5-ALA) as a photosensitizer for PDT to induce apoptosis in human malignant glioblastoma U87MG cells and to understand the underlying molecular mechanisms. Trypan blue dye exclusion test showed a decrease in cell viability after exposure to increasing doses of 5-ALA for 4h followed by PDT with a broad spectrum blue light (400-550 nm) at a dose of 18J/cm(2) for 1h and then incubation at 37 degrees C for 4h. Following 0.5 and 1mM 5-ALA-based PDT (5-ALA-PDT), Wright staining and ApopTag assay showed occurrence of apoptosis morphologically and biochemically, respectively. After 5-ALA-PDT, down regulation of nuclear factor kappa B (NFkappaB) and baculovirus inhibitor-of-apoptosis repeat containing-3 (BIRC-3) protein indicated inhibition of survival signals. Besides, 5-ALA-PDT caused increase in Bax:Bcl-2 ratio and mitochondrial release of cytochrome c and apoptosis-inducing factor (AIF). Activation of calpain, caspase-9, and caspase-3 occurred in course of apoptosis. Calpain and caspase-3 activities cleaved alpha-spectrin at specific sites generating 145kD spectrin breakdown product (SBDP) and 120kD SBDP, respectively. The results suggested that 5-ALA-PDT induced apoptosis in U87MG cells by suppression of survival signals and activation of proteolytic pathways. Thus, 5-ALA-PDT can be an effective strategy for inducing apoptosis in glioblastoma.

DHMEQ, a new NF-kappaB inhibitor, induces apoptosis and enhances fludarabine effects on chronic lymphocytic leukemia cells.

Chronic lymphocytic leukemia (CLL) is a low-grade lymphoid malignancy incurable with conventional modalities of chemotherapy. Strong and constitutive nuclear factor kappa B (NF-kappaB) activation is a characteristic of CLL cells. We examined the effects of a new NF-kappaB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on CLL cells. Dehydroxymethylepoxyquinomicin completely abrogated constitutive NF-kappaB activity and induced apoptosis of CLL cells. Apoptosis induced by DHMEQ was accompanied by downregulation of NF-kappaB-dependent antiapoptotic genes: c-IAP, Bfl-1, Bcl-X(L) and c-FLIP. Dehydroxymethylepoxyquinomicin also inhibited NF-kappaB induced by CD40 and enhanced fludarabine-mediated apoptosis of CLL cells. Results of this study suggest that inhibition of constitutive and inducible NF-kappaB by DHMEQ in combination with fludarabine is a promising strategy for the treatment of CLL.

[The effect of tanshinone â ¡A potentiates the effects of Cisplatin in Fadu cells in vitro through downregulation of survivin].

Objective:The aim of this study is to investigate the inhibitory effect and mechanism of tanshinone ⅡA combined with cisplatin on tumor Fadu cells in pharyngeal squamous cell carcinoma. Method:Cytotoxicity was determined by CCK8 assay. Flow cytometry was used to detect apoptosis and cell cycle distribution. Western blotting was used to assess the protein expression of related signaling proteins. Result:Compared with the two single drug groups treated with Tan ⅡA and DDP respectively, the combination group showed significantly higher anti-proliferative rate (P<0.01), arrested cell cycle at S phase, and resulted in observably higher apoptotic cell fractions in human hypopharyngeal squamous cell carcinomas Fadu cells; Western blotting showed that the protein expression of cleaved caspase 3 and cleaved PARP increased ,while survivin significantly decreased in the cells treated with the combination of tanshinone ⅡA and cisplatin. Conclusion:Tanshinone ⅡA potentiates the efficacy of Cisplatin in Fadu cells, which may be attributed to the downregulation of survivin protein expression.

Prostate-apoptosis-response-gene-4 increases sensitivity to TRAIL-induced apoptosis.

The capacity of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) to preferentially induce apoptosis in malignant cells while sparing normal tissues renders it an attractive therapeutic agent. Nevertheless, the molecular determinants governing sensitivity towards TRAIL remain to be defined. Acknowledging the previously demonstrated deregulation of prostate-apoptosis-response-gene-4 (par-4) in ex vivo cells of patients suffering from acute and chronic lymphatic leukemia, we here tested the hypothesis that expression of par-4 influences sensitivity to TRAIL. Evaluating this hypothesis we show, that par-4-transfected T-lymphoblastic Jurkat cells exhibit a considerably increased rate of apoptosis upon incubation with an agonistic TRAIL-antibody as compared to their mock-transfected counterparts. Defining the underlying molecular mechanisms we provide evidence, that par-4 enhances sensitivity towards TRAIL by employing crucial members of the extrinsic pathway. Thus, par-4-overexpressing Jurkat clones show an enforced cleavage of c-Flip(L) together with an increased activation of the initiator caspases-8 and -10. In addition, expression of par-4 enables cells to down-regulate the inhibitor-of-apoptosis proteins cIAP-1, cIAP-2, XIAP and survivin with a concomitantly enhanced activation of the executioner caspases-6 and -7. Supporting the crucial role of caspase-8 in par-4-promoted apoptosis we demonstrate that inhibition of caspase-8 considerably reduces TRAIL-induced apoptosis in par-4 and mock-transfected Jurkat clones and reverses the described molecular changes. In conclusion, we here provide first evidence that expression of par-4 in neoplastic lymphocytes augments sensitivity to TRAIL-induced cell death and outline the responsible molecular mechanisms, in particular the crucial role of caspase-8 activation.