Expression of the IAP protein family acts cooperatively to predict prognosis in human bladder cancer patients

Acidic Microenvironment Enhances Cisplatin Resistance in Bladder Cancer via Bcl-2 and XIAP

Cisplatin (CDDP) remains a key drug for patients with advanced bladder cancer (BC), despite the emergence of new therapeutic agents; thus, the identification of factors contributing to CDDP treatment resistance is crucial. As acidity of the tumor microenvironment has been reported to be associated with treatment resistance and poor prognosis across various cancer types, our objectives in this study were to investigate the effects of an acidic environment on BC cells and elucidate the mechanisms behind CDDP resistance. Our findings show that BC cells cultured under acidic conditions developed cisplatin resistance as acidity increased. Notably, CDDP administered to BC cells in a pH 6.0 environment required double the concentration, compared to those in a pH 7.5 environment, to achieve equivalent toxicity. Using chloroquine and navitoclax, we identified the involvement of the Bcl-2 and LC3B pathways in the acquisition of CDDP resistance under acidic conditions. A Western blot analysis revealed that the activations of Bcl-2 and XIAP expression appear to inhibit both apoptotic and autophagic cell death. Taken together, these results suggest that alleviating the acidity of the tumor microenvironment in clinical settings might enhance BC sensitivity to CDDP.

Inhibitor of apoptosis proteins as therapeutic targets in bladder cancer

Evasion from apoptosis is a hallmark of cancer. Inhibitor of apoptosis proteins (IAPs) contribute to this hallmark by suppressing the induction of cell death. IAPs were found to be overexpressed in cancerous tissues and to contribute to therapeutic resistance. The present review focuses on the IAP members cIAP1, cIAP2, XIAP, Survivin and Livin and their importance as potential therapeutic targets in bladder cancer.

Lipopolysaccharide sensitizes the therapeutic response of breast cancer to IAP antagonist

Inhibitor of apoptosis protein (IAP) is a class of E3 ubiquitin ligases functioning to support cancer survival and growth. Many small-molecule IAP antagonists have been developed, aiming to degrade IAP proteins to kill cancer. We have evaluated the effect of lipopolysaccharide (LPS), a component of the bacterial outer membrane, on IAP antagonists in treating breast cancer in a mouse model to guide future clinical trials. We show that LPS promotes IAP antagonist-induced regression of triple-negative breast cancer (TNBC) from MDA-MB-231 cells in immunodeficient mice. IAP antagonists such as SM-164, AT-406, and BV6, do not kill MDA-MB-231 cells alone, but allow LPS to induce cancer cell apoptosis rapidly. The apoptosis caused by LPS plus SM-164 is blocked by toll-like receptor 4 (TLR4) or MyD88 inhibitor, which inhibits LPS-induced TNFα production by the cancer cells. Consistent with this, MDA-MB-231 cell apoptosis induced by LPS plus SM-164 is also blocked by the TNF inhibitor. LPS alone does not kill MDA-MB-231 cells because it markedly increases the protein level of cIAP1/2, which is directly associated with and stabilized by MyD88, an adaptor protein of TLR4. ER⁺ MCF7 breast cancer cells expressing low levels of cIAP1/2 undergo apoptosis in response to SM-164 combined with TNFα but not with LPS. Furthermore, TNFα but not LPS alone inhibits MCF7 cell growth in vitro. Consistent with these, LPS combined with SM-164, but not either of them alone, causes regression of ER⁺ breast cancer from MCF7 cells in immunodeficient mice. In summary, LPS sensitizes the therapeutic response of both triple-negative and ER⁺ breast cancer to IAP antagonist therapy by inducing rapid apoptosis of the cancer cells through TLR4- and MyD88-mediated production of TNFα. We conclude that antibiotics that can reduce microbiota-derived LPS should not be used together with an IAP antagonist for cancer therapy.

Subcellular localization of X-linked inhibitor of apoptosis protein (XIAP) in cancer: does that matter?

X-linked inhibitor of apoptosis protein (XIAP) finely tunes the balance between survival and death to control homeostasis. XIAP is found aberrantly expressed in cancer, which has been shown to promote resistance to therapy-induced apoptosis and confer poor outcome. Despite its predominant cytoplasmic localization in human tissues, growing evidence implicates the expression of XIAP in other subcellular compartments in sustaining cancer hallmarks. Herein, we review our current knowledge on the prognostic role of XIAP localization and discuss molecular mechanisms underlying differential biological functions played in each compartment. The comprehension of XIAP subcellular shuttling and functional dynamics might provide the rationale for future anticancer therapeutics.

The Great Escape: The Power of Cancer Stem Cells to Evade Programmed Cell Death

Cancer is one of the primary causes of death worldwide. Tumour malignancy is related to tumor heterogeneity, which has been suggested to be due to a small subpopulation of tumor cells named cancer stem cells (CSCs). CSCs exert a key role in metastasis development, tumor recurrence, and also epithelial-mesenchymal transition, apoptotic resistance, self-renewal, tumorigenesis, differentiation, and drug resistance. Several current therapies fail to eradicate tumors due to the ability of CSCs to escape different programmed cell deaths. Thus, developing CSC-selective and programmed death-inducing therapeutic approaches appears to be of primary importance. In this review, we discuss the main programmed cell death occurring in cancer and the promising CSC-targeting agents developed in recent years. Even if the reported studies are encouraging, further investigations are necessary to establish a combination of agents able to eradicate CSCs or inhibit their growth and proliferation.

XIAP's Profile in Human Cancer

XIAP, the X-linked inhibitor of apoptosis protein, regulates cell death signaling pathways through binding and inhibiting caspases. Mounting experimental research associated with XIAP has shown it to be a master regulator of cell death not only in apoptosis, but also in autophagy and necroptosis. As a vital decider on cell survival, XIAP is involved in the regulation of cancer initiation, promotion and progression. XIAP up-regulation occurs in many human diseases, resulting in a series of undesired effects such as raising the cellular tolerance to genetic lesions, inflammation and cytotoxicity. Hence, anti-tumor drugs targeting XIAP have become an important focus for cancer therapy research. RNA-XIAP interaction is a focus, which has enriched the general profile of XIAP regulation in human cancer. In this review, the basic functions of XIAP, its regulatory role in cancer, anti-XIAP drugs and recent findings about RNA-XIAP interactions are discussed.

The Multiple Roles of the IAP Super-family in cancer

The Inhibitor of Apoptosis proteins (IAPs) are a family of proteins that are mainly known for their anti-apoptotic activity and ability to directly bind and inhibit caspases. Recent research has however revealed that they have extensive roles in governing numerous other cellular processes. IAPs are known to modulate ubiquitin (Ub)-dependent signaling pathways through their E3 ligase activity and influence activation of nuclear factor κB (NF-κB). In this review, we discuss the involvement of IAPs in individual hallmarks of cancer and the current status of therapies targeting these critical proteins.

XIAP Interaction with E2F1 and Sp1 via its BIR2 and BIR3 domains specific activated MMP2 to promote bladder cancer invasion

XIAP has generally been thought to function in bladder cancer. However, the potential function of structure-based function of XIAP in human BC invasion has not been well explored before. We show here that ectopic expression of the BIR domains of XIAP specifically resulted in MMP2 activation and cell invasion in XIAP-deleted BC cells, while Src was further defined as an XIAP downstream negative regulator for MMP2 activation and BC cell invasion. The inhibition of Src expression by the BIR domains was caused by attenuation of Src protein translation upon miR-203 upregulation; which was resulted from direct interaction of BIR2 and BIR3 with E2F1 and Sp1, respectively. The interaction of BIR2/BIR3 with E2F1/Sp1 unexpectedly occurred, which could be blocked by serum-induced XIAP translocation. Taken together, our studies, for the first time revealed that: (1) BIR2 and BIR3 domains of XIAP play their role in cancer cell invasion without affecting cell migration by specific activation of MMP2 in human BC cells; (2) by BIR2 interacting with E2F1 and BIR3 interacting with Sp1, XIAP initiates E2F1/Sp1 positive feedback loop-dependent transcription of miR-203, which in turn inhibits Src protein translation, further leading to MMP2-cleaved activation; (3) XIAP interaction with E2F1 and Sp1 is observed in the nucleus. Our findings provide novel insights into understanding the specific function of BIR2 and BIR3 of XIAP in BC invasion, which will be highly significant for the design/synthesis of new BIR2/BIR3-based compounds for invasive BC treatment.

A tumour-selective cascade activatable self-detained system for drug delivery and cancer imaging

Achieving the activation of drugs within cellular systems may provide targeted therapies. Here we construct a tumour-selective cascade activatable self-detained system (TCASS) and incorporate imaging probes and therapeutics. We show in different mouse models that the TCASS system accumulates in solid tumours. The molecules show enhanced accumulation in tumour regions via the effect of recognition induced self-assembly. Analysis of the molecular penetration in tumour tissue shows that in vivo self-assembly increases the penetration capability compared to typical soft or hard nanomaterials. Importantly, the in vivo self-assembled molecules exhibit a comparable clearance pathway to that of small molecules, which are excreted from organs of the reticuloendothelial system (liver and kidney), while are relatively slowly eliminated from tumour tissues. Finally, this system, combined with the NIR probe, shows high specificity and sensitivity for detecting bladder cancer in isolated intact patient bladders.

The activation of drugs within cellular systems may provide targeted therapies for cancer. Here, the authors make a drug delivery system that is activated within the cell and exploits XIAP expression to cleave a linker region, resulting in the self-assembly of the system and drug release within cancer cells.

Molecular characterization of low grade and high grade bladder cancer

Background

Bladder cancer (BC) is the 9^th most common cancer diagnosis worldwide. Low grade (LG) represents 70% of all BCs, characterized by recurrence and rare ability (10–15%) to progress to high grade (HG) and invade. The remaining 30% is high grade (HG), fast invasive BC, which is resistant to therapy. Identifying biomarkers for predicting those tumors able to progress is a key goal for patient outcome improvement. This study focuses on the most promising prognostic markers.

Materials and methods

TP53 and FGFR3 mutational status, Survivin, CK19, CK20, E-cadherin and CD44 gene expression analysis were performed on 66 BCs.

Results

Survivin was found associated to tumor grade (p<0.05). Moreover, Survivin correlated with CD44 in TP53 wild type (p = 0.0242) and FGFR3 wild type (p = 0.0036) tumors. In particular the Survivin-CD44 correlation was associated to HG FGFR3 wild type BCs (p = 0.0045). Unsupervised hierarchical clustering based on gene expression data identified four distinct molecular groups reflecting the patient histology (p = 0.038).

Conclusion

We suggest Survivin, both as a biomarker associated to G3 BCs but negatively related to TP53 mutational status, and as a potential novel therapeutic target.

Expression of Inhibitor of Apoptosis Gene Family Members in Bladder Cancer Tissues and the 5637 Tumor Cell Line

Background: Apoptosis is suppressed in cancer tissues and tumor cell lines because anti-apoptosis genes are overexpressed. The inhibitor of apoptosis proteins (IAP) gene family contributes to control of apoptosis. The expression profile of eight genes of the IAP family in biopsies from patients with a history of bladder cancer and normal bladder tissues, as well as a bladder tumor cell line (5637), was assessed in the present study. Methods: Cancer tissue samples were obtained at surgery and the 5637 tumor cell line was cultured in RPMI1640 medium. Beyond tumor margins were selected as normal tissue. Expressional profile of interested genes was obtained by using specific primers and the real-time PCR method. Results: The results showed that expression of seven of the studied genes was up-regulated in cancer tissues and the cell line whereas BIRC4 (XIAP) was down-regulated in both. Conclusions: The results showed that these genes were expressed to a greater extent in cancer tissue and cancer cells than in normal tissues. The data suggested that over-expression of anti-apoptotic genes such as IAP family members, can trigger cells to escape from apoptosis.

Recurring Amplification at 11q22.1-q22.2 Locus Plays an Important Role in Lymph Node Metastasis and Radioresistance in OSCC

A key feature in the pathogenesis of OSCC is genetic instability, which results in altered expression of genes located in amplified/deleted chromosomal regions. In a previous study we have shown that the amplification of the 11q22.1-q22.2 region, encoding cIAP1 and cIAP2, is associated with lymph node metastasis and poor clinical outcome in OSCC. Here, we validate the aCGH results by nuc ish and detect a weak amplification at the 11q22.1-q22.2 locus in 37% of the 182 samples tested. We find positive correlation of 11q22.1-q22.2 amplification with lymph node metastasis, reduced survival, and increased cancer recurrence, and we observe that patients with 11q22.1-q22.2 amplification fail to respond to radiotherapy. We confirm the concurrent overexpression of cIAP1 and cIAP2 and observe differential subcellular localization of the two proteins in OSCC. To ascertain the roles of cIAP1/cIAP2 in lymph node metastasis and radioresistance, we use an in vitro pre-clinical model and confirm the role of cIAP1 in invasion and the role of cIAP2 in invasion and migration. Studies of other tumor types in which cIAP1 is overexpressed suggest that multi-regimen treatments including SMAC mimetics may be effective. Thus, the evaluation of 11q22.1-q22.2 amplifications in OSCC patients may help choose the most effective treatment.

Characterization of inflammasome-related genes in urine sediments of patients receiving intravesical BCG therapy

BACKGROUND

Nowadays, the intravesical Bacillus Calmette-Guérin (BCG) instillation is the method of choice for the postsurgical treatment of high-grade nonmuscle-invasive bladder cancer , to reduce both recurrence rate and risk of progression. BCG is hypothesized to correct the immune system disequilibrium occurring during carcinogenesis, through an immunostimulation with detrimental effects for tumoral cells. Inflammation plays a crucial role in tumor progression. The deregulation of inflammasomes upon carcinogenesis underlines its importance both in physiologic and pathologic human conditions. Nucleotide oligomerization domain-like receptors (NLRs) are key components of this molecular platform and the increase in expression of some members of nucleotide oligomerization domain-like receptors family (NLRP3, NLRP4, NLRP9, and NLR family apoptosis inhibitory protein [NAIP]) in urothelial carcinoma was already demonstrated in our previous work. The first aim of the present work was to estimate whether these inflammasome-related genes show alterations during BCG instillations. The expression levels of NLRP3, NLRP4, NLRP9, and NAIP were assessed in the urine sediments from patients, which underwent surgery for superficial high-grade bladder cancer and further subjected to serial BCG instillations. The eventual association between NLR expression and recurrence was also evaluated. The expression of CK20 mRNA as confirmed marker of bladder cancer was also assayed.

METHODS

Urine were sampled from patients harboring high-grade superficial bladder cancer and treated postsurgically with weekly BCG instillations for 6 weeks (induction cycle, I). Urine sediments were processed and resulting RNA was reverse transcribed and used for amplification by real-time PCR.

RESULTS

After surgery, CK20 levels decreased significantly whereas NLRP4 and NLRP9 genes showed an increase. NLRP3 and NAIP remained substantially unmodified. CK20 mRNA decreased at the end of the induction cycle. NLRP3 did not show relevant modifications. The expression levels of NLRP4 and NLRP9 decreased significantly after 2 BCG administrations and remained substantially downregulated during the whole induction cycle. CK20 was higher in recurrence cases before BCG administration compared to the recurrence-free group, while no significant difference after BCG therapy was recorded. NLRP4 and NLRP9 were higher in patients with recurrence before BCG administration.

CONCLUSIONS

The study underlines the importance of NLRP4 and NLRP9 in urothelial carcinoma and if these preliminary data will be confirmed in larger cohort studies, the assessment of NLRP4 and NLRP9 expression levels could help to predict the BCG failure, playing a relevant role in decision making for early radical surgery.

BIRC7 and KLF4 expression in benign and malignant lesions of pancreas and their clinicopathological significance

This study investigated the KLF4 and BIRC7 protein expression in malignant and benign pancreatic tissues by immunohistochemical staining and the clinical and pathological significance of KLF4 and BIRC7 expression in PDAC. KLF4 expression was significantly lower, whereas BIRC7 expression was significantly higher in PDAC than that in peritumoral tissue, benign pancreatic lesions, and normal pancreatic tissue (P < 0.01). The percentage of positive BIRC7 and negative KLF4 expression was significantly lower in PDAC patients with well differentiated tumors, maximum tumor size < 3 cm, no lymph node metastasis, no invasion to the surrounding tissues and organs, and TNM stage I/II stage disease than in patients with poorly differentiated tumor, maximum tumor size > 5 cm, lymph node metastasis, invasion to surrounding tissues and organs, and TNM stage III/IV disease (P < 0.05 or P < 0.01). Kaplan-Meier survival analysis showed that the differentiation, maximum tumor size, TNM stage, lymph node metastasis, invasion, negative KLF4 expression, and positive BIRC7 expression were significantly associated with the short survival of patients with PDAC (P < 0.05 or P < 0.01). Cox multivariate analysis revealed that positive BIRC7 expression and negative KLF4 expression were independent poor prognosis factors in PDAC patients. In conclusions, positive BIRC7 expression and negative KLF4 expression are associated with the progression of PDAC and poor prognosis in patients with PDAC.

Characterization and functional analysis of two inhibitor of apoptosis genes in Zhikong scallop Chlamys farreri

The proteins of inhibitor of apoptosis (IAP) family play important roles in regulation of apoptosis, immunological response and cell proliferation. Here we reported two IAP genes (named CfIAP1 and CfIAP2) in Zhikong scallop Chlamys farreri. The full-length CfIAP1 cDNA contained 1552 nucleotides, encoding a predicted protein of 251 amino acids with two BIR domains. The full-length CfIAP2 cDNA contained 1243 nt, encoding a 356-aa protein with one BIR domain and one RING domain. The two genes are ubiquitously expressed in six types of tissue of C. farreri. The expression levels of CfIAP1 and CfIAP2 were significantly up-regulated after challenged with acute viral necrobiotic disease virus, lipopolysaccharide and exposure to air. Subcellular localization assay showed that CfIAP1 was mainly distributed in cytoplasm and CfIAP2 was in cytoplasm and nucleus. As assessed using a kit designed to test Caspase3 function in mammalian cells, the activity of CfCaspase3 was enhanced as a result of the down-regulation of CfIAP2 expression by dsRNA-mediated gene silencing. Our study indicated that CfIAP1 and CfIAP2 may participate in the innate immunity and stress responses and that CfIAP2 might block apoptosis via inhibiting CfCaspase3 indirectly through an unexplored mechanism in C. farreri.

ALKBH8 promotes bladder cancer growth and progression through regulating the expression of survivin

Human AlkB homolog 8 (ALKBH8) is highly expressed in high-grade, superficially and deeply invasive bladder cancer. Moreover, ALKBH8 knockdown induces apoptosis in bladder cancer cells. However, the underlying anti-apoptotic mechanism of ALKBH8 in bladder cancer cells has thus far remained unclear. Moreover, there is no direct evidence that highly expressed ALKBH8 is involved in tumor progression in vivo. We here show that ALKBH8 knockdown induced apoptosis via downregulating the protein expression of survivin, an anti-apoptotic factor also exhibiting increased levels in bladder cancer. We also clarify that ALKBH8 transgenic mice showed an accelerated rate of bladder tumor mass and invasiveness in an N-butyl-N-(4-hydroxybutyl)-nitrosamine-induced bladder cancer model. These findings suggest that the high expression of ALKBH8 is critical for the growth and progression of bladder cancer.

The effects of Livin shRNA on the response to cisplatin in HepG2 cells

Hepatocellular carcinoma is a lethal malignancy with poor prognosis, partially due to tumor metastasis, recurrence and resistance to chemo- or radio-therapy. Cisplatin can inhibit cancer cell DNA replication, and is widely used in the clinical treatment of tumors. The present study aimed to generate eukaryotic expression vectors for Livin shRNA and to examine the effects of Livin shRNA on the chemosensitivity of HepG2 hepatocellular carcinoma cells. Eukaryotic expression vectors for Livin shRNA (pSD11-U6/Neo/GFP/Livin) were designed and constructed. The HepG2 hepatocellular carcinoma cell line was transfected with this vector using the liposome method. The expression levels of Livin mRNA and protein were measured by quantitative polymerase chain reaction and western blot analysis. The rate of cell growth inhibition was measured using MTT assay following treatment of the cells with cisplatin (2.0 mg/l). DNA sequencing confirmed that the construction of the eukaryotic expression vector for Livin shRNA had been successful. Transfection of these vectors into HepG2 cells led to a significant reduction in the expression levels of Livin mRNA and protein (P<0.05). Cisplatin treatment was associated with significantly higher rates of cell growth inhibition in HepG2 cells transfected with Livin shRNA compared with those that were not transfected (P<0.05). The vectors constructed in the present study produced effective inhibition of the Livin gene in HepG2 cells and increased the chemosensitivity of hepatocellular carcinoma cells.

Effects of siRNA Livin on EJ human bladder cancer cells treated with mitomycin-C

The aim of this study was to observe the inhibitory and therapeutic effects of small interfering RNA (siRNA) targeting Livin in EJ human bladder cancer cells. Specific siRNA targeting Livin was synthesized and transfected into EJ human bladder cancer cells treated or not treated with mitomycin-C (MMC). Livin mRNA and protein, as well as proliferation and apoptosis of EJ cells was examined with reverse transcription-polymerase chain reaction, western blotting, Cell Counting Kit-8 assay and flow cytometry, respectively. The results indicated that the expression of Livin mRNA and protein in EJ cells was significantly decreased by siRNA Livin. The proliferation of EJ cells was significantly inhibited by treatment with MMC and transfection of siRNA Livin. The inhibition of cell proliferation by treatment with MMC was further enhanced by transfection of siRNA Livin. The apoptotic rate of cells transfected with siRNA Livin and treated with MMC was significantly higher than those cells receiving a single transfection of siRNA Livin and single treatment of MMC. In conclusion, the present study demonstrates that transfection of siRNA Livin induces growth suppression and apoptosis in EJ human bladder cancer cells, and increases the chemotherapeutic sensitivity of cells to MMC.

Harnessing the apoptotic programs in cancer stem-like cells

Elimination of malignant cells is an unmet challenge for most human cancer types even with therapies targeting specific driver mutations. Therefore, a multi-pronged strategy to alter cancer cell biology on multiple levels is increasingly recognized as essential for cancer cure. One such aspect of cancer cell biology is the relative apoptosis resistance of tumor-initiating cells. Here, we provide an overview of the mechanisms affecting the apoptotic process in tumor cells emphasizing the differences in the tumor-initiating or stem-like cells of cancer. Further, we summarize efforts to exploit these differences to design therapies targeting that important cancer cell population.

Prognostic value of survivin in patients with non-Hodgkin's lymphoma: a meta-analysis

BACKGROUND AND OBJECTIVES

Numerous studies have focused on the role of survivin in non-Hodgkin's lymphomas (NHLs), but evidence regarding the prognostic value of survivin with respect to overall survival (OS) in NHL remains controversial. The aim of this study is to gain a better insight about the direct relationship between survivin expression and patients' survival statuses.

MATERIALS AND METHODS

Relevant publications addressing the association between survivin expression and OS in NHL patients were selected from PubMed, Embase, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure Database (CNKI), China Science and Technology Journal Database (VIP), Wanfang Database and the Cochrane library. Studies were pooled and summary hazard ratios (HR) were calculated. Sensitivity analyses and publication bias were also conducted. Statistical analysis was performed by STATA 12.0 software.

RESULTS

12 studies met the inclusion criteria. Combined HRs suggested that survivin overexpression had an unfavorable impact on NHL patients' survival (HR=1.55, 95% CI=1.12-2.13, P=0.008). Subgroup analyses according to the studies categorized by histological type, ethnicity, cutoff scores and follow-up period were also conducted, and all the above analyses supported the stability of the prognostic role of survivin.

CONCLUSION

Our findings suggest that survivin high expression might be a poor prognostic factor for patients with NHL. However, further large scale studies are needed to confirm these findings.

Discovery of Sanggenon G as a natural cell-permeable small-molecular weight inhibitor of X-linked inhibitor of apoptosis protein (XIAP)

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Discovery of a novel XIAP-inhibitory natural compound from Morus root bark (Sanggenon G).

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Sanggenon G binds specific to the BIR3 domain of XIAP in a low μM range.

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Sanggenon G interferes with XIAP-BIR3-substrate binding in living cells.

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Sanggenon G acts as chemosensitizer in tumor cell lines with high XIAP expression.

Defects in the regulation of apoptosis are one main cause of cancer development and may result from overexpression of anti-apoptotic proteins such as the X-linked inhibitor of apoptosis protein (XIAP). XIAP is frequently overexpressed in human leukemia and prostate and breast tumors. Inhibition of apoptosis by XIAP is mainly coordinated through direct binding to the initiator caspase-9 via its baculovirus-IAP-repeat-3 (BIR3) domain. XIAP inhibits caspases directly making it to an attractive target for anti-cancer therapy. In the search for novel, non-peptidic XIAP inhibitors in this study we focused on the chemical constituents of sāng bái pí (mulberry root bark). Most promising candidates of this plant were tested biochemically in vitro by a fluorescence polarization (FP) assay and in vivo via protein fragment complementation analysis (PCA). We identified the Diels Alder adduct Sanggenon G (SG1) as a novel, small-molecular weight inhibitor of XIAP. As shown by FP and PCA analyses, SG1 binds specifically to the BIR3 domain of XIAP with a binding affinity of 34.26 μM. Treatment of the transgenic leukemia cell line Molt3/XIAP with SG1 enhances caspase-8, -3 and -9 cleavage, displaces caspase-9 from XIAP as determined by immunoprecipitation experiments and sensitizes these cells to etoposide-induced apoptosis. SG1 not only sensitizes the XIAP-overexpressing leukemia cell line Molt3/XIAP to etoposide treatment but also different neuroblastoma cell lines endogenously expressing high XIAP levels. Taken together, Sanggenon G (SG1) is a novel, natural, non-peptidic, small-molecular inhibitor of XIAP that can serve as a starting point to develop a new class of improved XIAP inhibitors.

Prognostic significance of survivin in breast cancer: meta-analysis

Survivin, an inhibitor of apoptosis protein, is a potentially prognostic factor and therapeutic target in breast carcinoma, but no consensus exists based on heterogeneous data. The aim of this present study is to clarify the prognostic relevance of survivin in breast cancer patients. Relevant articles were screened in PubMed and EMBASE databases. Patients' clinical characteristics, overall survival (OS), disease/recurrence-free survival (DFS/RFS) and positive expressed survivin rates were extracted for further analysis. Statistics extracted from Kaplan-Meier survival curves were calculated indirectly with methods developed by Parmar, Williamson, and Tierney. Multivariate Cox hazard regression analysis data were used directly in Stata 11.0. Pooled hazard ratio (HR) and 95% confidence interval (CI) were calculated to evaluate the prognostic role of survivin in breast cancer. Online literature search identified 23 articles containing 3,259 breast cancer patients. Our meta-analysis of all included studies about survival outcomes showed positive correlation between poor prognosis and survivin expression. Pooled HRs (95% CIs) for OS and DFS/RFS were 1.37 (1.12-1.68) and 1.34 (1.02-1.76), respectively. Subgroup analyses considering methods used to detect survivin (immunohistochemistry or not) and localization of survivin (whole, nuclear or cytoplasm of the cell) were also conducted, and all the above analyses supported the stability of the prognostic role of survivin. In addition, our study revealed a significant association between survivin expression and lymph node metastasis (OR: 2.74; 95% CI: 1.27-5.93) or stage of breast cancer (OR: 2.01; 95% CI: 1.29-3.13). Positive expression of survivin demonstrated a significantly higher risk of recurrence and decreased OS rates in breast cancer.

microRNA-99a inhibiting cell proliferation, migration and invasion by targeting fibroblast growth factor receptor 3 in bladder cancer

The expression of microRNA-99a (miRNA-99a) has been investigated in a number of human cancers. It has been reported to be downregulated in several types of cancer, including ovarian carcinoma, squamous cell carcinoma of the tongue, squamous cell lung carcinoma, hepatocellular carcinoma, bladder cancer, prostate cancer and childhood adrenocortical tumors. In the present study, the effects of miRNA-99a on bladder cancer cell proliferation, migration and invasion were examined. Following transfection of miRNA-99a, cell viability, cell migration assay, cell invasion, western blot analysis and luciferase assays were conducted in bladder cancer cell lines. It was found that miRNA-99a inhibits cell proliferation, migration and invasion in T24 and EJ cells. Additionally, this study provided the first evidence that miRNA-99a is likely to directly target fibroblast growth factor receptor 3 in bladder cancer. The study provided evidence that miRNA-99a suppresses cell proliferation, migration and invasion by targeting growth factor receptor 3 in bladder cancer cell lines. These results indicated that it could be investigated as a target for therapeutic drugs designed to treat bladder cancer.

Tissue microarray analysis of X-linked inhibitor of apoptosis (XIAP) expression in breast cancer patients

The goal of this study was to determine the diagnostic and prognostic potential of X-linked inhibitor of apoptosis (XIAP) expression in breast cancer. We analyzed a tissue microarray comprised of 100 breast cancer cases and 70 matched normal samples. Analysis of an online database, which included 2,977 patients, was also performed. There was a significant difference in cytoplasmic expression of XIAP (XIAP-C) between breast cancer tissue and matched normal (p<0.001). Staining of XIAP-C was defined as negative (breast cancer 8.42% vs. normal 30.91%), slight (40.0 vs. 45.45%), moderate (43.16 vs. 23.64%), or high (8.42 vs. 0%). High XIAP-C protein expression correlated with human epidermal growth factor receptor 2 (HER-2) status (p=0.010) and with human p53 mutant-type (P53) status (p=0.039). We found that XIAP expression did not correlate with disease-free survival (p=0.706) and overall survival (p=0.496) of breast cancer patients. An Internet-based system analysis confirmed our results. In the subgroup analysis, basal-like breast cancer patients with high XIAP levels in the tumor had a significantly increased risk of relapse; thus, the up-regulation of XIAP appeared to be predictive of poor relapse-free survival (p=0.013). Kaplan-Meier curves also identified a significant correlation between distant metastasis-free survival and XIAP expression in patients with lymph-node-negative disease (p=0.030). In summary, expression of XIAP-C was significantly higher in breast cancer compared to normal tissue. XIAP-C expression correlated with HER-2 status and may be considered a prognostic biomarker for basal-like breast cancer patients.

Expression and clinical significance of livin protein in hepatocellular carcinoma

In this study, the two-step PV method of immunohistochemistry was used to determine livin protein expression in HCC tissues, pericarcinoma tissues, hepatitis/hepatic cirrhosis tissues, and normal hepatic tissues, and livin protein expression was detected in the blood plasma of patients with HCC before and after surgery, subjects with hepatic cirrhosis and hepatitis, and healthy blood donors using ELISA. Livin protein expression was significantly higher in HCC tissues than that in normal hepatic tissues and hepatitis/hepatic cirrhosis tissues, with no significant difference between HCC tissues and pericarcinoma tissues. The HCC patients with positive livin protein expression had a significantly higher survival rate than those with negative livin protein expression. Livin protein expression was significantly higher in the blood plasma of patients with HCC before and after surgery and in patients with hepatic cirrhosis and hepatitis than that in healthy blood donors, whereas livin protein expression in the blood plasma of patients with HCC was not significantly different from that of patients with hepatic cirrhosis and hepatitis. Livin protein expression in HCC tissues did not correlate with that in the blood plasma of the same HCC patients. Livin protein expression may be a potential, effective indicator for assessing prognosis in patients with HCC.