Expression of Livin, an antiapoptotic protein, is an independent favorable prognostic factor in childhood acute lymphoblastic leukemia

Livin/BIRC7 gene expression as a possible diagnostic biomarker for endometrial hyperplasia and carcinoma

BACKGROUND

Livin/BIRC7 is a member of the inhibitors of apoptosis proteins family which are implicated in development of cancer through the inhibition of apoptosis process. This case-control study was intended to investigate livin/BIRC7 gene expression in endometrial hyperplasia and carcinoma and its correlation to some oxidative stress markers in addition to its possible diagnostic performance.

METHODS

This study included 90 participants [30 endometrial hyperplasia patients, 30 endometrial carcinoma patients, and 30 healthy controls]. Livin/BIRC7 gene expression was analyzed using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Serum catalase activity was assessed by enzyme-linked immunosorbent assay (ELISA) and malondialdehyde level was measured by the colorimetric method.

RESULTS

Livin/BIRC7 gene expression was significantly (p < 0.001) higher in endometrial carcinoma from patients with endometrial hyperplasia when compared to controls. A positive correlation was found between livin/BIRC7 expression and serum catalase activity and malondialdehyde level in endometrial hyperplasia and carcinoma. The detection of livin/BIRC7 in endometrial carcinoma has excellent sensitivity and specificity.

CONCLUSIONS

Livin/BIRC7 was overexpressed in endometrial carcinoma with excellent power to differentiate endometrial carcinoma from endometrial hyperplasia or healthy subjects, suggesting that it might be a useful molecular marker for endometrial carcinoma diagnosis.

TREM2 promotes natural killer cell development in CD3-CD122+NK1.1+ pNK cells

Background

Triggering receptor expressed on myeloid cells 2 (TREM2) signaling is considered to regulate anti-inflammatory responses in macrophages, dendritic cell maturation, osteoclast development, induction of obesity, and Alzheimer’s disease pathogenesis. However, little is known regarding the effect of TREM2 on natural killer (NK) cells.

Results

Here, we demonstrated for the first time that CD3⁻CD122⁺NK1.1⁺ precursor NK (pNK) cells expressed TREM2 and their population increased in TREM2-overexpressing transgenic (TREM2-TG) mice compared with that in female C57BL/6 J wild type (WT) mice. Both NK cell-activating receptors and NK cell-associated genes were expressed at higher levels in various tissues of TREM2-TG mice than in WT mice. In addition, bone marrow-derived hematopoietic stem cells (HSCs) of TREM2-TG mice (TG-HSCs) successfully differentiated into NK cells in vitro, with a higher yield from TG-HSCs than from WT-HSCs. In contrast, TREM2 signaling inhibition by TREM2-Ig or a phosphatidylinositol 3-kinase (PI3K) inhibitor affected the expression of the NK cell receptor repertoire and decreased the expression levels of NK cell-associated genes, resulting in significant impairment of NK cell differentiation. Moreover, in melanoma-bearing WT mice, injection of bone marrow cells from TREM2-TG mice exerted greater antitumor effects than that with cells from WT control mice.

Conclusions

Collectively, our data clearly showed that TREM2 promoted NK cell development and tumor regression, suggesting TREM2 as a new candidate for cancer immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00420-0.

Leflunomide ameliorates experimental autoimmune myasthenia gravis by regulating humoral and cellular immune responses

Leflunomide, an immunosuppressive disease-modifying anti-rheumatic drug (DMARD), is widely used in the treatment of rheumatoid arthritis (RA), psoriatic arthritis (PA) as well as multiple sclerosis. However, its role in myasthenia gravis (MG) has not yet been clearly explored. Here, we investigated the effect of leflunomide on experimental autoimmune myasthenia gravis (EAMG) in vivo and in vitro. The results demonstrated that leflunomide alleviated the severity of EAMG associated with reduced serum total anti-acetylcholine receptor (AChR) IgG levels. During the development of EAMG, the increase of follicular helper T cells (Tfh) 1, Tfh 17 cells and decrease of follicular regulatory T cells (Tfr) were reversely altered after leflunomide administration. Our work further found that leflunomide might inhibit Tfh cells through the IL-21/STAT3 pathway to reduce the secretion of antibodies by B cells. In addition, leflunomide rebuilt the balance of Th1/Th2/Th17/Treg subsets. These results suggested that leflunomide ameliorated EAMG severity by regulating humoral immune responses and Th cell profiles thereby providing a novel effective treatment strategy for MG.

Novel targeted mtLivin nanoparticles treatment for disseminated diffuse large B-cell lymphoma

We previously showed that Livin, an inhibitor of apoptosis protein, is specifically cleaved to produce a truncated protein, tLivin, and demonstrated its paradoxical proapoptotic activity. We further demonstrated that mini-tLivin (MTV), a 70 amino acids derivative of tLivin, is a proapoptotic protein as potent as tLivin. Based on these findings, in this study we aimed to develop a venue to target MTV for the treatment of diffuse large B-cell lymphoma (DLBCL). MTV was conjugated to poly (lactide-co-glycolic acid) surface-activated nanoparticles (NPs). In order to target MTV-NPs we also conjugated CD40 ligand (CD40L) to the surface of the NPs and evaluated the efficacy of the bifunctional CD40L-MTV-NPs. In vitro, CD40L-MTV-NPs elicited significant apoptosis of DLBCL cells. In a disseminated mouse model of DLBCL, 37.5% of MTV-NPs treated mice survived at the end of the experiment. Targeting MTV-NPs using CD40L greatly improved survival and 71.4% of these mice survived. CD40L-MTV-NPs also greatly reduced CNS involvement of DLBCL. Only 20% of these mice presented infiltration of lymphoma to the brain in comparison to 77% of the MTV-NPs treated mice. In a subcutaneous mouse model, CD40L-MTV-NPs significantly reduced tumor volume in correlation with significant increased caspase-3 activity. Thus, targeted MTV-NPs suggest a novel approach to overcome apoptosis resistance in cancer.

Apoptosis in Autoimmunological Diseases, with Particular Consideration of Molecular Aspects of Psoriasis

Apoptosis is a natural physiological process involving programmed cell death. Thanks to this process, it is possible to maintain the homeostasis of the body and the immune system. Dysfunctions of this mechanism lead to development of autoimmune diseases such as psoriasis; these diseases are chronic and treatment is extremely difficult. In psoriasis (a skin disease), apoptosis disorders are manifested by keratinocyte proliferation dysfunction. Autoimmune diseases coexisting with psoriasis include multiple sclerosis, autoimmune thyroid disease, and diabetes, but the common pathogenesis of these diseases is not fully understood. Given the heterogenous nature and chronic and recurrent course of psoriasis, the selection of an effective therapeutic strategy is still a problem. This literature review was focused on the process of apoptosis as a factor in the development of autoimmune diseases, with particular emphasis on psoriasis. The work also includes a review of therapeutic methods of psoriasis based on the latest literature.

AK002210 promotes the proliferation, migration and invasion of trophoblast cell through regulating miR-590/NAIP signal axis

Preeclampsia (PE) is a pregnancy-related syndrome and has become the leading cause of maternal and neonatal morbidity and mortality. LncRNA has been elucidated to play critical roles in the phenotype of trophoblast cells. However, the effect of AK002210 has not been reported. We aim to investigate the effect of AK002210 on the phenotype of trophoblast cells. Quantitative reverse transcription PCR was used to assess the gene expression. CCK-8 assay was used to evaluate the cell proliferation. Transwell assay was performed to detect the migration and invasion of trophoblast cells. Luciferase assay and rescue experiment were carried out to verify the interaction between miR-590-3p and AK002210 as well as NLR family apoptosis inhibitory protein (NAIP). The results revealed that AK002210 promoted the proliferation, migration and invasion of trophoblast cell while AK002210 knockdown inhibited that. Mechanically, we found that AK002210 was targeted by miR-590-3p. Moreover, miR-590-3p also directly targets NAIP which served as a ceRNA of AK002210. Rescue experiment showed that miR-590-3p reversed the effect of AK002210 which further confirmed their interaction. Moreover, AK002210 was proved to participated in the regulation of ERK/MMP-2 signal axis. In conclusion, we found that AK002210 knockdown may play a critical role in the progression of PE via miR-590-3p/NAIP and ERK/MMP signaling. It has potential to be a novel prognostic or therapeutic marker of PE.

A correlation between BCL-2 modifying factor, p53 and livin gene expressions in cancer colon patients

Accumulating evidence has revealed that livin gene and BCL-2 modifying factor (BMF) gene are closely associated with the initiation and progression of colon carcinoma by activating or suppressing multiple malignant processes. Those genes that can detect colon - cancer are a promising approach for cancer screening and diagnosis. This study aimed to evaluate correlation between livin, BMF and p53 genes expression in colon cancer tissues of patients included in the study, and their relationship with clinicopathological features and survival outcome in those patients. In this study, 50 pathologically diagnosed early cancer colon patients included and their tissue biopsy with 50 matched adjacent normal tissue, and 50 adenoma tissue specimens were analyzed for livin gene and BMF gene expressions using real time PCR. The relationship of those genes expressions with clinicopathological features, tumor markers, Time to Progression and overall survival for those patients were correlated in cancer colon group. In this study, there was a significant a reciprocal relationship between over expression of livin gene and down regulation of BMF and p53 genes in colon cancer cells. Livin mRNA was significantly higher, while BMF and p53 mRNA were significantly lower in colorectal cancer tissue compared to benign and normal colon tissue specimens (P < 0.001), however, this finding was absent between colon adenomas and normal mucosa. There was a significant association between up regulation of livin and down regulation of BMF and p53 expressions with more aggressive tumor (advanced TNM stage), rapid progression with metastasis and decreased overall survival in cancer colon patients, hence these genes can serve as significant prognostic markers of poor outcome in colon cancer patients. This work highlights the role of livin, BMF and p53 genes in colorectal tumorigenesis and the applicability of using those genes as a diagnostic and prognostic markers in patients with colon carcinoma and as a good target for cancer colon treatment in the future.

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Apoptosis and anti-apoptotic markers are a hallmark in cancer.

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There is a reciprocal relation between anti-apoptotic livin and proapoptotic BMF and P53 genes expression.

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Upregulation of livin and downregulation of BMF and P 53 genes expression are markers of poor prognosis in colon cancer.

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High livin expression is associated with more aggressive tumors with rapid progressions and metastasis.

A pilot study of Livin gene and Yes-associated protein 1 expression in hepatocellular carcinoma patients

Background

Livin gene and Yes-Associated Protein 1 (YAP1 (play a pivotal role in organ size control and tumorigenesis.

Aim

In the present pilot study, we investigate the expression of Livin gene and YAP1 in hepatitis C virus (HCV) associated hepatocellular carcinoma (HCC) compared to other HCV patients and controls.

Methods: the studied patients were divided into three groups 30 patients in each group in addition to 30 healthy subjects as a control group. Relative quantification of Livin gene and YAP-1 were assessed by quantitative Real Time RT-PCR (qPCR) in all studied patients and healthy controls. other laboratory investigations were done including complete blood count (CBC),international normalized ratio (INR) as well as liver function tests and tumor markers.

Results

Significant overexpression of Livin gene and YAP-1 was detected in HCC group followed by Hepatitis C Virus (HCV) untreated group then HCV treated group. The relative quantitation (RQ) of both genes showed positive correlation to the carcinoembryonic antigen (CEA) level and a significant relation was found between higher level of Livin and YAP1 genes and tumor size. The overall survival rate was low in those patients with high levels of Livin and YAP 1 genes so they were considered as indicators of a bad prognosis.

Conclusion

There is overexpression of Livin gene and YAP1 in hepatocellular carcinoma patients. They can be used as indicators of bad prognosis of the disease pathway together with low survival rate.

Destined to Die: Apoptosis and Pediatric Cancers

Apoptosis (programmed cell death) is a systematic and coordinated cellular process that occurs in physiological and pathophysiological conditions. Sidestepping or resisting apoptosis is a distinct characteristic of human cancers including childhood malignancies. This review dissects the apoptosis pathways implicated in pediatric tumors. Understanding these pathways not only unraveled key molecules that may serve as potential targets for drug discovery, but also molecular nodes that integrate with other signaling networks involved in processes such as development. This review presents current knowledge of the complex regulatory system that governs apoptosis with respect to other processes in pediatric cancers, so that fresh insights may be derived regarding treatment resistance or for more effective treatment options.

Livin participates in resistance to trastuzumab therapy for breast cancer through ERK1/2 and AKT pathways and promotes EMT-like phenotype

Trastuzumab resistance has emerged as a major issue in anti-human epidermal growth factor receptor-2 (HER2) therapy for breast cancers. The cell lines maintain overexpression of HER2. Upon treatment with trastuzumab, R-SKBR3 and R-BT474 cell lines displayed an increased growth rate and invasiveness, accompanied by activation of the ERK1/2 and AKT signaling pathways, and also a parental EMT-like transition (epithelial–mesenchymal transition) was promoted, with increases in N-cadherin, vimentin, and fibronectin and a decrease in E-cadherin. A further investigation found that livin played a key role in the development of trastuzumab resistance. Knockdown of the expression of livin by livin-shRNA3 in R-SKBR3 and R-BT474 cells decreased ERK1/2 and AKT, resensitized the resistant cells to the therapeutic activities of trastuzumab by inducing growth arrest, inhibition of proliferation, and G1-S cell cycle checking in the presence of the antibody, and they also exhibited an EMT-like transition (epithelial–mesenchymal transition), with a decrease in N-cadherin and an increase in E-cadherin, and the cell invasiveness was inhibited in response to the downregulation of livin. Conversely, SKBR3 and BT474 cells that had been stably transfected with pcDNA3.1-livin underwent promotion of an EMT-like transition and displayed a significant decrease in E-cadherin and increases in N-cadherin, vimentin, and fibronectin, and ectopic expression of livin in HER2-overexpressing breast cancer cells conferred resistance to trastuzumab. In vivo, the administration of livin AS (antisense oligonucleotides) restored sensitivity to trastuzumab in resistant breast cancer xenografts via the ERK1/2 and AKT signaling pathways. Patients with livin-overexpressing breast cancers exhibited significantly poorer responses to trastuzumab-based therapy than those with normal livin levels. In summary, our data suggest that the upregulation of livin activates the ERK1/2 and AKT signaling pathways and promotes an EMT-like transition. This could be an important mechanism that leads to trastuzumab resistance in HER2-overexpressing breast cancer cells.

Trastuzumab resistance has emerged as a major issue in anti-human epidermal growth factor receptor-2 (HER2) therapy for breast cancers.

Livin/BIRC7 expression as malignancy marker in adrenocortical tumors

Livin/BIRC7 is a member of the inhibitors of apoptosis proteins family, which are involved in tumor development through the inhibition of caspases. Aim was to investigate the expression of livin and other members of its pathway in adrenocortical tumors and in the adrenocortical carcinoma (ACC) cell line NCI-H295R.

The mRNA expression of livin, its isoforms α and β, XIAP, CASP3 and DIABLO was evaluated by qRT-PCR in 82 fresh-frozen adrenal tissues (34 ACC, 25 adenomas = ACA, 23 normal adrenal glands = NAG). Livin protein expression was assessed by immunohistochemistry in 270 paraffin-embedded tissues (192 ACC, 58 ACA, 20 NAG). Livin, CASP3 and cleaved caspase-3 were evaluated in NCI-H295R after induction of livin overexpression.

Relative livin mRNA expression was significantly higher in ACC than in ACA and NAG (0.060 ± 0.116 vs 0.004 ± 0.014 and 0.002 ± 0.009, respectively, p < 0.01), being consistently higher in tumors than in adjacent NAG and isoform β more expressed than α. No significant differences in CASP3, XIAP and DIABLO levels were found among these groups. In immunohistochemistry, livin was localized in both cytoplasm and nuclei. The ratio between cytoplasmic and nuclear staining was significantly higher in ACC (1.51 ± 0.66) than in ACA (0.80 ± 0.35) and NAG (0.88 ± 0.27; p < 0.0001). No significant correlations were observed between livin expression and histopathological parameters or clinical outcome. In NCI-H295R cells, the livin overexpression slightly reduced the activation of CASP3, but did not correlate with cell viability.

In conclusion, livin is specifically over-expressed in ACC, suggesting that it might be involved in adrenocortical tumorigenesis and represent a new molecular marker of malignancy.

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.

Livin modulates the apoptotic effects of vesicular stomatotitis virus in lung adenocarcinoma

Vesicular stomatitis virus (VSV) has shown promise in cancer treatment. However, it achieved limited effects against lung cancer. Lung cancer has intrinsic mechanisms that render resistance to VSV. In this study, we attempted to explore the expression of the anti-apoptotic factor Livin in lung adenocarcinoma and its possible relationship to VSV vulnerability. We found VSV induced apoptosis in a time- and dose-dependent manner, with the concomitant change in the expression of Livin. We elevated the expression of Livin both transiently and stably, and the cells became insensitive to VSV treatment. We further found the BIR domain of Livin was mainly responsible for its modulation effects. This finding suggested a possible interaction with the second mitochondria-derived activator of caspase (SMAC). The knock-down of SMAC also inhibited apoptosis by VSV. The relationship was confirmed by the co-immunoprecipitation. Finally, we knocked down the endogenous Livin, and the knock-down sensitized cells to VSV treatment. Our results suggested the important role of Livin and its partner molecule in the process of VSV treatment.

Identifying new targets in leukemogenesis using computational approaches

There is a need to identify novel targets in Acute Lymphoblastic Leukemia (ALL), a hematopoietic cancer affecting children, to improve our understanding of disease biology and that can be used for developing new therapeutics. Hence, the aim of our study was to find new genes as targets using in silico studies; for this we retrieved the top 10% overexpressed genes from Oncomine public domain microarray expression database; 530 overexpressed genes were short-listed from Oncomine database. Then, using prioritization tools such as ENDEAVOUR, DIR and TOPPGene online tools, we found fifty-four genes common to the three prioritization tools which formed our candidate leukemogenic genes for this study. As per the protocol we selected thirty training genes from PubMed. The prioritized and training genes were then used to construct STRING functional association network, which was further analyzed using cytoHubba hub analysis tool to investigate new genes which could form drug targets in leukemia. Analysis of the STRING protein network built from these prioritized and training genes led to identification of two hub genes, SMAD2 and CDK9, which were not implicated in leukemogenesis earlier. Filtering out from several hundred genes in the network we also found MEN1, HDAC1 and LCK genes, which re-emphasized the important role of these genes in leukemogenesis. This is the first report on these five additional signature genes in leukemogenesis. We propose these as new targets for developing novel therapeutics and also as biomarkers in leukemogenesis, which could be important for prognosis and diagnosis.

Increased μ-Calpain Activity in Blasts of Common B-Precursor Childhood Acute Lymphoblastic Leukemia Correlates with Their Lower Susceptibility to Apoptosis

Childhood acute lymphoblastic leukemia (ALL) blasts are characterized by inhibited apoptosis promoting fast disease progress. It is known that in chronic lymphocytic and acute myeloid leukemias the reduced apoptosis is strongly related with the activity of calpain-calpastatin system (CCS) composed of cytoplasmic proteases--calpains--performing the modulatory proteolysis of key proteins involved in cell proliferation and apoptosis, and of their endogenous inhibitor--calpastatin. Here, the CCS protein abundance and activity was for the first time studied in childhood ALL blasts and in control bone marrow CD19+ B cells by semi-quantitative flow cytometry and western blotting of calpastatin fragments resulting from endogenous calpain activity. Significantly higher μ-calpain (CAPN1) gene transcription, protein amounts and activity (but not those of m-calpain), with calpastatin amount and transcription of its gene (CAST) greatly varying were observed in CD19(+) ALL blasts compared to control cells. Significant inverse relation between the amount/activity of calpain and spontaneous apoptosis was noted. Patients older than 10 years (considered at higher risk) displayed increased amounts and activities of blast calpain. Finally, treatment of blasts with the tripeptide calpain inhibitors II and IV significantly and in dose-dependent fashion increased the percentage of blasts entering apoptosis. Together, these findings make the CCS a potential new predictive tool and therapeutic target in childhood ALL.

Caspase-1 inhibitor ameliorates experimental autoimmune myasthenia gravis by innate dendric cell IL-1-IL-17 pathway

BACKGROUND

IL-1β has been shown to play a pivotal role in autoimmunity. Cysteinyl aspartate-specific proteinase-1 (caspase-1) inhibitor may be an important drug target for autoimmune diseases. However, the effects of caspase-1 inhibitor on myasthenia gravis (MG) remain undefined.

METHODS

To investigate the effects of caspase-1 inhibitor on experimental autoimmune myasthenia gravis (EAMG), an animal model of MG, caspase-1 inhibitor was administered to Lewis rats immunized with region 97-116 of the rat AChR α subunit (R97-116 peptide) in complete Freund's adjuvant. The immunophenotypical characterization by flow cytometry and the levels of autoantibody by ELISA were carried out to evaluate the neuroprotective effect of caspase-1 inhibitor.

RESULTS

We found that caspase-1 inhibitor improved EAMG clinical symptom, which was associated with decreased IL-17 production by CD4+ T cells and γδ T cells, lower affinity of anti-R97-116 peptide IgG. Caspase-1 inhibitor decreased expression of CD80, CD86, and MHC class II on DCs, as well as intracellular IL-1β production from DCs. In addition, caspase-1 inhibitor treatment inhibited R97-116 peptide-specific cell proliferation and decreased follicular helper T cells relating to EAMG development.

CONCLUSIONS

Our results suggest that caspase-1 inhibitor ameliorates experimental autoimmune myasthenia gravis by innate DC IL-1-IL-17 pathway and provides new evidence that caspase-1 is an important drug target in the treatment of MG and other autoimmune diseases.

Inhibition of livin expression suppresses cell proliferation and enhances chemosensitivity to cisplatin in human lung adenocarcinoma cells

Livin is a novel member of the inhibitor of apoptosis protein family that has been reported to be overexpressed in various types of human malignancy. Although several studies have demonstrated that livin may be used as an effective target for tumor therapy, few studies have investigated its role in human lung adenocarcinoma. In the present study, two different methods were used in order to investigate the tumor‑suppressing effect of livin in human lung adenocarcinoma cells. Firstly, small interfering (si)RNA technology was used to down regulate livin expression; siRNA-mediated knockdown of livin was confirmed using reverse transcription quantitative polymerase chain reaction and western blot analysis, and cell proliferations was assessed using an MTT assay in vitro. Secondly, inhibition of livin expression was induced through the synergistic inhibitory effect between flavopiridol and tumor necrosis factor‑related apoptosis-inducing ligand (TRAIL). Experimental results revealed that, following transfection of the livin gene-silencing vector, the gene expression of livin was markedly decreased, SPC-A1 cell proliferation was significantly reduced and the therapeutic effect of the chemotherapy drug cisplatin was markedly improved. This growth inhibitory effect was also observed in the flavopiridol and TRAIL combination treatment group. In the flavopiridol and TRAIL combination treatment group, the protein expression of livin was significantly reduced and the survival rate of SPC‑A1 cells was significantly lower than the flavopiridol and TRAIL single operation group. In conclusion, the RNA silencing and the synergistic inhibitory effect between flavopiridol with TRAIL was able to effectively inhibit the expression of livin, significantly decrease SPC-A1 tumor cell proliferation and significantly enhance sensitivity to the chemotherapy drug cisplatin. These findings suggest that livin may be used as a novel target for tumor gene therapy.

p21(WAF1) modulates drug-induced apoptosis and cell cycle arrest in B-cell precursor acute lymphoblastic leukemia

p21(WAF1) is a well-characterized mediator of cell cycle arrest and may also modulate chemotherapy-induced cell death. The role of p21(WAF1) in drug-induced cell cycle arrest and apoptosis of acute lymphoblastic leukemia (ALL) cells was investigated using p53-functional patient-derived xenografts (PDXs), in which p21(WAF1) was epigenetically silenced in T-cell ALL (T-ALL), but not in B-cell precursor (BCP)-ALL PDXs. Upon exposure to diverse cytotoxic drugs, T-ALL PDX cells exhibited markedly increased caspase-3/7 activity and phosphatidylserine (PS) externalization on the plasma membrane compared with BCP-ALL cells. Despite dramatic differences in apoptotic characteristics between T-ALL and BCP-ALL PDXs, both ALL subtypes exhibited similar cell death kinetics and were equally sensitive to p53-inducing drugs in vitro, although T-ALL PDXs were significantly more sensitive to the histone deacetylase inhibitor vorinostat. Transient siRNA suppression of p21(WAF1) in the BCP-ALL 697 cell line resulted in a moderate depletion of the cell fraction in G1 phase and marked increase in PS externalization following exposure to etoposide. Furthermore, stable lentiviral p21(WAF1) silencing in the BCP-ALL Nalm-6 cell line accelerated PS externalization and cell death following exposure to etoposide and vorinostat, supporting previous findings. Finally, the Sp1 inhibitor, terameprocol, inhibited p21(WAF1) expression in Nalm-6 cells exposed to vorinostat and also partially augmented vorinostat-induced cell death. Taken together, these findings demonstrate that p21(WAF1) regulates the early stages of drug-induced apoptosis in ALL cells and significantly modulates their sensitivity to vorinostat.

Expression of the apoptosis inhibitor livin in colorectal adenoma-carcinoma sequence: correlations with pathology and outcome

The inhibitor of apoptosis family member livin is expressed in several types of cancer but not in most benign tissues, and it has been considered to be a poor prognostic mark in various malignancies. However, livin expression and its prognostic relevance have not been evaluated in colorectal adenoma-carcinoma sequence. In this study, we analyzed the difference of livin expression among normal mucosa, adenoma, and adenocarcinoma and investigated the relationship of livin expression in carcinomas with clinicopathological variables using immunohistochemistry and real-time reverse transcription-PCR. We observed that the expression of livin protein was mainly present on base of colorectal crypts in adenoma and throughout the epithelium in carcinoma, whereas did not present in accompanying normal mucosa, and the expression of livin messenger RNA (mRNA) in adenocarcinomas was significantly higher than in adenomas and in normal mucosa (P = 0.001, respectively), whereas, compared with normal mucosa, the expression level of livin mRNA was up-regulated in adenomas but no significant difference (P = 0.196). We also found that the expression levels of livin mRNA in rectal cancer was significantly higher than those in colonic cancer, and livin mRNA expression was strongly related to colorectal cancer invasive depth but not to clinical tumor stage, differentiation, lymph node metastasis, tumor morphological category and pathological type, and patient's age and gender. These findings support the possibility that the livin gene may play a role in colorectal tumorigenesis, and increased expression of livin mRNA may serve as a new target for colorectal cancer treatment.

Relationship between expression of Livin and the biological behavior of human oral squamous cell carcinoma

Livin is one of the most important members of the inhibitor protein (IAP) family. It is overexpressed in several types of tumors and may have prognostic significance. The purpose of this study was to investigate Livin expression in human oral squamous cell carcinomas (OSCCs) and to determine whether Livin affects tumor cell behavior in OSCC cell lines and thus evaluate its potential usefulness in serving as a possible target for molecular-targeted therapy in a preclinical model. The expression of Livin protein was investigated in human OSCC tissues through immunohistochemistry and western blot analysis. To evaluate the impact of Livin knockdown on the behavior of human OSCC cell lines, invasion, migration, proliferation and apoptosis assays using small-interfering RNA (siRNA) were performed. RT-PCR and western blot analysis were used to assess alteration of Livin expression at the mRNA and protein levels. The results revealed that expression of Livin was increased in the human OSCC tissues compared with the adjacent normal mucosa. In addition, immunoreactivity of Livin was expressed in 8 OSCC tissues (44.4%). Knockdown of Livin resulted in significantly reduced cell invasion, migration and proliferation in the human OSCC cells. Livin knockdown induced cell apoptosis in the human OSCC cells. Moreover, Livin inhibited apoptosis by suppressing the activity of caspases in the human OSCC cells. In conclusion, livin is associated with invasive and oncogenic phenotypes such as tumor cell invasion, tumor cell migration, tumor cell proliferation, and resistance to apoptosis in human OSCC cells.

Expression and prognostic significance of livin/BIRC7 in childhood acute lymphoblastic leukemia

Livin, a member of the inhibitor of apoptosis proteins has been considered to be a poor prognostic marker in malignancies. However, little is known about the clinical relevance of livin expression in childhood acute lymphoblastic leukemia (ALL). The aim of the present study was to assess the expression of livin on leukemic blasts of de novo childhood ALL and its relevance to clinical and hematological findings, and treatment outcome. The expression of livin was analyzed in 80 patients with newly diagnosed childhood ALL using quantitative reverse transcriptase-polymerase chain reaction. The results of the study revealed that the expression levels of livin were higher in patients with favorable prognostic factors. Furthermore, livin expression was associated with a favorable early response to chemotherapy (leukemic blast <25% day 7 bone marrow response) (P = 0.001). Patients with high livin expression were associated with significantly higher CR rate (P = 0.02) and lower mortality rate (P = 0.05) than those with low livin expression. Kaplan-Meier curves demonstrated that high livin expression was associated with significantly longer DFS (P = 0.004) and overall survival (P = 0.02). Multivariate analysis demonstrated that livin expression was independent favorable prognostic factor for OS and DFS (P = 0.05 and P = 0.01, respectively). This study suggests that livin expression could be a novel prognostic marker in childhood ALL thus it could be incorporated into patient stratification and treatment protocols.

Inhibitor of Apoptosis (IAP) proteins in hematological malignancies: molecular mechanisms and therapeutic opportunities

Inhibitor of Apoptosis (IAP) proteins exert essential functions during tumorigenesis as well as treatment resistance by simultaneously blocking cell death pathways and promoting cell survival. As IAP proteins are typically aberrantly expressed in human cancers including hematological malignancies, they represent in principle promising targets for therapeutic interventions. There are currently exciting opportunities to rationally exploit the therapeutic targeting of IAP proteins for the treatment of leukemia and lymphoma. Further insights into the signaling pathways that are under the control of IAP proteins and into the specific IAP protein-dependent vulnerabilities of hematological neoplasms are expected to pave the avenue to novel treatment strategies.

Inhibitor of apoptosis proteins in pediatric leukemia: molecular pathways and novel approaches to therapy

Inhibitor of Apoptosis (IAP) proteins are a family of proteins with antiapoptotic functions that contribute to the evasion of apoptosis, a form of programed cell death. IAP proteins are expressed at high levels in a variety of human cancers including childhood acute leukemia. This elevated expression has been associated with unfavorable prognosis and poor outcome. Therefore, IAP proteins are currently exploited as therapeutic targets for cancer drug discovery. Consequently, small-molecule inhibitors or antisense oligonucleotides directed against IAP proteins have been developed over the last years. Indeed, IAP antagonists proved to exhibit in vitro and in vivo antitumor activities against childhood pediatric leukemia in several preclinical studies. Thus, targeting IAP proteins represents a promising molecular targeted strategy to overcome apoptosis resistance in childhood leukemia, which warrants further exploitation.

Livin expression is an independent factor in rectal cancer patients with or without preoperative radiotherapy

BACKGROUND

This study was aimed to investigate the expression significance of Livin in relation to radiotherapy (RT), clinicopathological and biological factors of rectal cancer patients.

METHODS

This study included 144 primary rectal cancer patients who participated in a Swedish clinical trial of preoperative radiotherapy. Tissue microarray samples from the excised primary rectal cancers, normal mucosa and lymph node metastases were immunostained with Livin antibody. The proliferation of colon cancer cell lines SW620 and RKO was assayed after Livin knock-down.

RESULTS

The expression of Livin was significantly increased from adjacent (P = 0.051) or distant (P = 0.028) normal mucosa to primary tumors. 15.4% (2/13) and 39.7% (52/131) patients with Livin-negative and positive tumors died at 180 months after surgery, and the difference tended to be statistically significant (P = 0.091). In multivariate analyses, the difference achieved statistical significance, independent of TNM stage, local and distant recurrence, grade of differentiation, gender, and age (odds ratio = 5.09, 95% CI: 1.01-25.64, P = 0.048). The in vitro study indicated colon cancer cells with Livin knock-down exhibited decreased proliferation compared with controls after RT.

CONCLUSIONS

The expression of Livin was was independently related to survival in rectal cancer patients, suggesting Livin as a useful prognostic factor for rectal 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.

IAP proteins as targets for drug development in oncology

The inhibitors of apoptosis (IAPs) constitute a family of proteins involved in the regulation of various cellular processes, including cell death, immune and inflammatory responses, cell proliferation, cell differentiation, and cell motility. There is accumulating evidence supporting IAP-targeting in tumors: IAPs regulate various cellular processes that contribute to tumor development, such as cell death, cell proliferation, and cell migration; their expression is increased in a number of human tumor samples, and IAP overexpression has been correlated with tumor growth, and poor prognosis or low response to treatment; and IAP expression can be rapidly induced in response to chemotherapy or radiotherapy because of the presence of an internal ribosome entry site (IRES)-dependent mechanism of translation initiation, which could contribute to resistance to antitumor therapy. The development of IAP antagonists is an important challenge and was subject to intense research over the past decade. Six molecules are currently in clinical trials. This review focuses on the role of IAPs in tumors and the development of IAP-targeting molecules for anticancer therapy.

IAPs on the move: role of inhibitors of apoptosis proteins in cell migration

Inhibitors of Apoptosis Proteins (IAPs) are a class of highly conserved proteins predominantly known for the regulation of caspases and immune signaling. However, recent evidence suggests a crucial role for these molecules in the regulation of tumor cell shape and migration by controlling MAPK, NF-κB and Rho GTPases. IAPs directly control Rho GTPases, thus regulating cell shape and migration. For instance, XIAP and cIAP1 function as the direct E3 ubiquitin ligases of Rac1 and target it for proteasomal degradation. IAPs are differentially expressed in tumor cells and have been targeted by several cancer therapeutic drugs that are currently in clinical trials. Here, we summarize the current knowledge on the role of IAPs in the regulation of cell migration and discuss the possible implications of these observations in regulating tumor cell metastases.

Overexpression of the truncated form of Livin reveals a complex interaction with caspase-3

Disruption in apoptosis are involved in cancer development and progression. Livin-β, has been identified as a critical modulator for cell death in several tumor cell lines. It was demonstrated that a truncated fragment of Livin-β (tLivin) without its N-terminal 52 amino acids is produced in cells through protein cleavage. However, the biological consequence of the cleavage remains largely ignored. In the present study, we report that tLivin exerted a pro-apoptotic effect on cells. The subcellular localization of tLivin was mainly restricted to the cytoplasm. To explore the underlying mechanism, we observed an elevated caspase-3 activity which may account for the apoptosis. Furthermore, we observed that tLivin was further cleaved into a smaller fragment in cells. This second cleavage was possibly related to activated caspase-3. The resulted C-terminal fragment (livC) was an anti-apoptotic factor. Our study may help to deepen our understanding of the role of Livin in the regulation of cell death.

Atorvastatin-modified dendritic cells in vitro ameliorate experimental autoimmune myasthenia gravis by up-regulated Treg cells and shifted Th1/Th17 to Th2 cytokines

Conventional therapies for autoimmune diseases produce nonspecific immune suppression, which are usually continued lifelong to maintain disease control, and associated with a variety of adverse effects. In this study, we found that spleen-derived dendritic cells (DCs) from the ongoing experimental autoimmune myasthenia gravis (EAMG) rats can be induced into tolerogenic DCs by atorvastatin in vitro. Administration of these tolerogenic DCs to EAMG rats on days 5 and 13 post immunization (p.i.) resulted in improved clinical symptoms, which were associated with increased numbers of CD4(+)CD25(+) T regulatory (Treg) cells and Foxp3 expression, decreased lymphocyte proliferation among lymph node mononuclear cells (MNC), shifted cytokine profile from Th1/Th17 to Th2 type cytokines, decreased level of anti-R97-116 peptide (region 97-116 of the rat acetylcholine receptor α subunit) IgG antibody in serum. These tolerogenic DCs can migrate to spleen, thymus, popliteal and inguinal lymph nodes after they were injected into the EAMG rats intraperitoneally. Furthermore, these tolerogenic DCs played their immunomodulatory effects in vivo mainly by decreased expression of CD86 and MHC class II on endogenous DCs. All these data provided us a new strategy to treat EAMG and even human myasthenia gravis (MG).

Livin promotes progression of breast cancer through induction of epithelial-mesenchymal transition and activation of AKT signaling

The inhibitor of apoptosis proteins (IAP) are closely correlated with proliferation, apoptosis, motility, and metastasis. Livin is the most recently identified IAP, and its role in breast progression remains unknown. In our study, analyses of 50 patients with breast cancer revealed that the positive expression rate of Livin was higher in breast cancer tissues (62%) relative to that in adjacent (35%) and normal tissues (25%). Livin expression in breast cancer correlated with the clinical stage and axillary lymph node metastasis and could be used as a prognostic marker. Our in vitro experiment revealed that Livin was highly expressed in high-invasive MDA-MB-231 cells as compared to low-invasive cells (MCF-7). Suppression of Livin by short-hairpin RNA reduced the Livin expression of MDA-MB-231 cells and subsequently inhibited tumor cell growth, proliferation, and colony formation and induced tumor cell apoptosis, motility, migration, and invasion. Overexpression of Livin in MCF7 cells resulted in increased migration and invasion capabilities of the cells without affecting proliferation and apoptosis. In addition, epithelial-mesenchymal transition (EMT) was induced by Livin expression in breast cancer cell lines. The high level of phosphorylated AKT in MDA-MB-231 cells was suppressed by Livin knockdown. Further, Livin-induced migration and invasion could be abolished by either the application of the phosphoinositide-3-kinase inhibitor LY294002 or knockdown of AKT expression using small-interfering RNA. In conclusion, Livin serves as an independent prognostic indicator for breast cancer. Livin expression promotes breast cancer metastasis through the activation of AKT signaling and induction of EMT in breast cancer cells both in vitro and in vivo.

Upregulation of the antiapoptotic factor Livin contributes to cisplatin resistance in colon cancer cells

The antiapoptotic factor Livin has been considered critical for tumor progression and poor prognosis for variant types of tumors. However, there are only limited reports regarding its expression and biological functions in colon cancer. Here, we examined Livin expression in four colon cancer cell lines (HCT116, RKO, KM12C, and SW620) in the presence or absence of cisplatin that was used as a model reagent. We found the different response to cisplatin was related to endogenous Livin expression level. From among a panel of apoptosis-related factors (p53, Bcl-2, Bcl-XL, BAX, and survivin), the expression of Livin was upregulated after cisplatin treatment in a dose-dependent manner. Both immunocytochemistry and nuclear cytoplasmic fractionation indicated Livin remained in the cytoplasm after treatment with cisplatin. In an attempt to explore the mechanism, we found the elevated expression of Livin was not due to the decreased degradation by proteosome but was enhanced at the mRNA level. Besides, cisplatin treatment activated the mammalian target of rapamycin (mTOR) pathway as shown by increased phosphorylation of Akt1, mTOR, S6K, and 4E-BP1, together with the elevated Livin. The PI3K inhibitor LY294002 inhibited both the phosphorylation of mTOR and upregulation of Livin. The stable overexpression of Livin inhibited the activation of caspase-3 and led to resistance to cisplatin, while the knockdown of Livin by siRNA rendered colon cancer cells more sensitive to cisplatin. Our study, along with others, highlighted the potential of Livin for cancer therapy in colon cancer.

Livin expression may be regulated by miR-198 in human prostate cancer cell lines

Livin has been recently described as an inhibitor of apoptosis, which is established to be associated with a variety of cancers. Metastatic prostate cancer cell line DU145 expresses high level of Livin mRNA yet low level of its protein. Thus, we hypothesised that Livin was regulated by some miRNAs in prostate cancer cells. Livin mRNA and protein expression were investigated by reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blot, respectively. Hairpin RT-PCR was performed to analyse suspected miRNAs. Livin 3'-untranslated region (3'-UTR) wild type and mutant dual-luciferase reporter vectors were constructed. The miRNAs targeting Livin were predicted by the online software - TargetScan and miRBase, and then validated by dual luciferase reporter gene assay. We found that post-transcriptional inhibition of Livin occurred in DU145 cells, assumedly due to the miRNA pathway. Among 6 candidate miRNAs, miR-198 expression was identified to be negatively correlated with Livin expression level in some prostate cancer cell lines. Further study revealed miR-198-mediated repression of Livin expression. Therefore, the regulation of Livin expression may involve miR-198 in prostate cancer cell lines.

Rapid engraftment of human ALL in NOD/SCID mice involves deficient apoptosis signaling

Previously, we found that rapid leukemia engraftment (short time to leukemia, TTL^short) in the NOD/SCID/huALL (non-obese diabetic/severe combined immuno-deficiency/human acute lymphoblastic leukemia) xenograft model is indicative of early patient relapse. As earlier intact apoptosis sensitivity was predictive for good prognosis in patients, we investigated the importance of apoptosis signaling on NOD/SCID/huALL engraftment. Intact apoptosome function as reflected by cytochrome c-related activation of caspase-3 (CRAC-positivity) was strongly associated with prolonged NOD/SCID engraftment (long time to leukemia, TTL^long) of primary leukemia cells, good treatment response and superior patient survival. Conversely, deficient apoptosome function (CRAC-negativity) was associated with rapid engraftment (TTL^short) and early relapse. Moreover, an intact apoptosis signaling was associated with high transcript and protein levels of the pro-apoptotic death-associated protein kinase1 (DAPK1). Our data strongly emphasize the impact of intrinsic apoptosis sensitivity of ALL cells on the engraftment phenotype in the NOD/SCID/huALL model, and most importantly also on patient outcome.

The clinical effect of the inhibitor of apopotosis protein livin in melanoma

OBJECTIVE

The inhibitor of apoptosis protein (IAP) livin is frequently overexpressed in melanoma. Livin binds caspases and thereby inhibits apoptosis. We found that caspases cleave livin to produce a truncated form with a paradoxical proapoptotic activity.

METHODS

We assessed the correlation of livin expression with survival among 114 melanoma patients treated with an autologous melanoma vaccine. In 52 patients, resection resulted in no evidence of disease (NED) and 62 remained with active disease (WAD). Protein levels were assessed using Western blot.

RESULTS

We found livin protein expression in 44/114 samples (38.4%). Median overall survival was 1.4 years in NED patients with high levels of livin protein, 8.4 years in those with low-intermediate levels and not reached in patients who did not express livin (p = 0.025). The corresponding overall survival was 2.3 years among WAD patients with high levels of livin protein, 11.3 years in those with low-intermediate levels and, paradoxically, only 4.0 years in patients who did not express livin (p = 0.012).

CONCLUSION

Livin protein expression may play a role in the progression of melanoma and correlates with survival. A high level of the protein is associated with a poor prognosis. However, in WAD patients low to intermediate level of livin, rather than absence of the protein, is associated with a favorable prognosis. This is probably due to the paradoxical proapoptotic activity of this important regulator of apoptosis.

Apoptosis inhibition or inflammation: the role of NAIP protein expression in Hodgkin and non-Hodgkin lymphomas compared to non-neoplastic lymph node

Background

Inhibitors of Apoptosis (IAP) family play a critical role in apoptosis and inflammatory response. Neuronal Apoptosis Inhibitory Protein (NAIP), as a member of both IAPs and NLR families (NOD-Like Receptor), is a unique IAP harboring NOD (Nucleotide Oligomerization Domain) and LLR (Leucine Rich Repeat) motifs. Considering these motifs in NAIP, it has been suggested that the main function of NAIP is distinct from other members of IAPs. As a member of NLR, NAIP mediates the assembly of 'Inflammasome' for inflammatory caspase activation. Pathologic expression of NAIP has been reported not only in some infectious and inflammatory diseases but also in some malignancies. However, there is no report to elucidate NAIP expression in lymphomatic malignancies.

Methods

In this study, we examined NAIP protein expression in 101 Formalin-Fixed Paraffin-Embedded blocks including samples from 39 Hodgkin Lymphoma and 23 Non Hodgkin Lymphoma cases in comparison with 39 control samples (30 normal and 9 Reactive Lymphoid Hyperplasia (RLH) lymph nodes) using semi-quantitative immuno-flourecent Staining.

Results

NAIP expression was not statistically different in lymphoma samples neither in HL nor in NHL cases comparing to normal samples. However, we evaluated NAIP expression in normal and RLH lymph nodes. Surprisingly, we have found a statistically significant-difference between the NAIP expression in RLH (M.R of NAIP/GAPDH expression = 0.6365 ± 0.017) and normal lymph node samples (M.R of NAIP/GAPDH expression = 0.5882 ± 0.047) (P < 0.01).

Conclusions

These findings show that the regulation of apoptosis could not be the main function of NAIP in the cell, so the pathologic expression of NAIP is not involved in lymphoma. But, we concluded that the over expression of NAIP has more effective role in the inflammatory response. Also, this study clarifies the NAIP expression level in lymphoma which is required for IAPs profiling in order to be used in potential translational applications of IAPs.

Targeting IAP proteins for therapeutic intervention in cancer

Evasion of apoptosis is one of the crucial acquired capabilities used by cancer cells to fend off anticancer therapies. Inhibitor of apoptosis (IAP) proteins exert a range of biological activities that promote cancer cell survival and proliferation. X chromosome-linked IAP is a direct inhibitor of caspases - pro-apoptotic executioner proteases - whereas cellular IAP proteins block the assembly of pro-apoptotic protein signalling complexes and mediate the expression of anti-apoptotic molecules. Furthermore, mutations, amplifications and chromosomal translocations of IAP genes are associated with various malignancies. Among the therapeutic strategies that have been designed to target IAP proteins, the most widely used approach is based on mimicking the IAP-binding motif of second mitochondria-derived activator of caspase (SMAC), which functions as an endogenous IAP antagonist. Alternative strategies include transcriptional repression and the use of antisense oligonucleotides. This Review provides an update on IAP protein biology as well as current and future perspectives on targeting IAP proteins for therapeutic intervention in human malignancies.

Exploiting inhibitor of apoptosis proteins as therapeutic targets in hematological malignancies

Resistance to apoptosis is one of the hallmarks of human cancers and contributes to the insensitivity of many cancers to commonly used treatment approaches. Inhibitor of apoptosis (IAP) proteins, a family of anti-apoptotic proteins, have an important role in evasion of apoptosis, as they can both block apoptosis-signaling pathways and promote survival. High expression of IAP proteins is observed in multiple cancers, including hematological malignancies, and has been associated with unfavorable prognosis and poor patients' outcome. Therefore, IAP proteins are currently considered as promising molecular targets for therapy. Indeed, drug-discovery approaches over the last decade aiming at neutralizing IAP proteins have resulted in the generation of small-molecule inhibitors or antisense oligonucleotides that demonstrated in vitro and in vivo antitumor activities in preclinical studies. As some of these strategies have already entered the stage of clinical evaluation, for example, in leukemia, an update on this promising molecular-targeted strategy to interfere with apoptotic pathways is of broad interest.

BIRC6/Apollon gene expression in childhood acute leukemia: impact on therapeutic response and prognosis

OBJECTIVE

Although BIRC6/Apollon seems to play a critical role as an antiapoptotic regulator, its clinical relevance in acute leukemia remains largely elusive. Therefore, we aimed to investigate BIRC6 gene expression in childhood acute leukemia in relation to clinicopathological characteristics at presentation, therapeutic response, and prognosis.

METHODS

BIRC6 expression level was assessed in 75 children with acute leukemia; 30 patients with acute myeloblastic leukemia (AML) and 45 patients with acute lymphoblastic leukemia (ALL) using real-time quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

The median level of BIRC6 expression did not differ significantly between AML and ALL patients. BIRC6 expression level was higher in patients with AML and ALL with extramedullary involvement, white blood cell (WBC) count ≥ 10 × 10(9) /L, and unfavorable cytogenetics at diagnosis. BIRC6 gene expression was higher in patients with unfavorable response to therapy at day 14, those who developed relapse or died in both leukemic groups. The best cutoff value of BIRC6 to predict therapeutic response and disease outcome was determined. AML and ALL patients with BIRC6 overexpression had significantly shorter overall and disease free survivals.

CONCLUSIONS

This is the first report to study BIRC6 gene in pediatric ALL. Our results suggested that BIRC6 gene expression could be considered as an adverse risk factor in childhood acute leukemia and, hence, could be used to guide therapeutic regimens.

Expression of inhibitor of apoptosis protein (IAP) livin/BIRC7 in acute leukemia in adults: correlation with prognostic factors and outcome

The clinical relevance of livin/BIRC7 expression is still controversial in different types of malignancies, therefore this study was designed to evaluate the gene expression of livin in Egyptian adult AML and ALL. Livin expression level was higher in patients with unfavorable prognostic factors at diagnosis in both ALL (p=0.002) and AML (p=0.042) and its level was negatively correlated with event free survival (EFS) and overall survival (OS) in both ALL (p<0.001for both) and AML (p=0.001 and 0.023 respectively). This study suggests that livin expression is a novel prognostic marker in adult acute leukemia and thus needs to be incorporated into the patient stratification and treatment protocols.

Quantitative assessment of MLAA-34 expression in diagnosis and prognosis of acute monocytic leukemia

MLAA-34 is a newly identified monocytic leukemia-associated antigen. Previous data indicated that MLAA-34 might be a novel anti-apoptosis factor related closely to carcinogenesis or progression of acute monocytic leukemia. The over-expression of MLAA-34 is intuitively expected to be associated with unfavorable clinical features in acute myeloid leukemia. However, there have been no clinical studies about the prognostic relevance of MLAA-34 expression in human malignancies. This study was done to investigate the clinical relevance of the expression of MLAA-34 in de novo acute myeloid leukemia. In 126 patients with de novo acute myeloid leukemia, the level of MLAA-34 expression and protein expression ratio were determined by using quantitative reverse transcriptase-PCR and western blot, respectively. The results were analyzed with respect to the patients' clinical features and treatment outcomes. Both MLAA-34 expression rates and expression levels were found to be higher in patients with the French-American-British classification subtype M5, and the expression levels were also higher in patients with a leukocyte number of ≥ 20 × 10(9)/L and patients with extramedullary disease. In addition, MLAA-34 over-expression (≥ median expression) was associated with an unfavorable day 7 response to induction chemotherapy and also associated with a poor survival rate. In multivariate analysis, high MLAA-34 levels was independently associated with a poorer relapse-free survival and overall survival in AML patients. In conclusion, our data indicate that MLAA-34 may be used as a prognostic marker for treatment decision-making in acute monocytic leukemia through validation by further studies.

Expression and prognostic significance of the apoptotic genes BCL2L13, Livin, and CASP8AP2 in childhood acute lymphoblastic leukemia

Improved treatment of childhood acute lymphoblastic leukemia (ALL) depends on the identification of new molecular markers that are able to predict treatment response and clinical outcome. The development of impaired apoptosis in leukemic cells is one factor that may influence their response to treatment. We investigated the expression of three apoptosis related genes, BCL2L13, CASP8AP2, and Livin, as well as their prognostic significance, in a retrospective study of 90 pediatric ALL patients diagnosed between 1996 and 2007 in Taiwan. Univariant analysis revealed that high expression of BCL2L13 was associated with inferior event-free survival and overall survival (p<0.001 and 0.005, respectively). Multivariate analysis for EFS and OS demonstrated that high expression of BCL2L13 was an independent prognostic factor for childhood ALL in this ethnic group.

Livin gene plays a role in drug resistance of colon cancer cells

OBJECTIVE

The objective of this study was to investigate the effect of knockdown of Livin expression on reversing drug resistance phenotype of colon cancer HCT-8/V cells.

DESIGN AND METHODS

Specific short hairpin RNA (shRNA) was chosen and transfected in human colon cancer HCT-8/V cell line. Cell apoptosis and chemosensitivity were evaluated following downregulation of Livin expression.

RESULTS

In the current study, Livin was found to be highly expressed in the HCT-8/V colon cancer cells, which were resistant to several anti-tumor drugs. Knocking down of Livin expression in HCT-8/V cells by specific RNAi facilitated the apoptosis of HCT-8/V cells in response to vincristine (VCR), etoposide (VP-16), and 5-flourouracil (5-FU). Chemosensitivity assay confirmed the results and demonstrated the reversal of drug resistance phenotype of HCT-8/V cells.

CONCLUSION

These data suggest that specific silencing of Livin gene expression could be a promising target for further research in clinical chemotherapy of colon cancer.

Livin abrogates apoptosis of SPC-A1 cell by regulating JNKI signaling pathway

Livin, a novel member of inhibitors of apoptosis protein, is highly expressed in tumor tissues. It is a potential target in tumor therapy. Silencing its gene expression has been found to promote tumor cell apoptosis or increase tumor sensitivity to therapies. This paper studied the effect of livin anti-apoptotic activity and examined its molecular mechanisms. In the study, higher levels of cell apoptosis were measured by FACS in the experiment group with livin expression silenced than that in controls (P < 0.05). After livin gene expression was knocked down, cleaved caspase-3 protein was up-regulated but caspase-3 mRNA expression was almost the same, the phosphorylated JNK1 protein was down-regulated but JNK1 mRNA and total JNK1 protein expression was approximately the same too. The results suggest that livin may exert anti-apoptotic action on SPC-A1 by activating JNK1 signaling pathway and inhibiting caspase-3 activation.

Overexpression of X-linked inhibitor of apoptosis protein (XIAP) is an independent unfavorable prognostic factor in childhood de novo acute myeloid leukemia

The overexpression of X-linked inhibitor of apoptosis protein (XIAP), a member of IAP family protein, is intuitively expected to be associated with unfavorable clinical features in malignancies; however, there have been only a very limited number of studies reporting the clinical relevance of XIAP expression. This study was performed to investigate the prognostic relevance of XIAP expression in childhood acute myeloid leukemia (AML). In 53 children with de novo AML, the level of XIAP expression was determined by using quantitative reverse transcriptase-polymerase chain reaction and was analyzed with respect to the clinical characteristics at diagnosis and treatment outcomes. As a result, the XIAP expression was found to be higher in patients with extramedullary disease than in those without (P=0.014). In addition, XIAP overexpression (>or=median expression) was associated with an unfavorable day 7 response to induction chemotherapy and also associated with a worse 3-yr relapsefree survival rate (52.7+/-20.9% vs. 85.9+/-14.8%, P=0.014). Multivariate analyses revealed that XIAP overexpression was an independent unfavorable prognostic factor for relapse-free survival (hazard ratio, 6.16; 95% confidence interval, 1.48-25.74; P=0.013). Collectively, XIAP overexpression may be used as an unfavorable prognostic marker in childhood AML.

The inhibitor of apoptosis protein Livin (ML-IAP) plays a dual role in tumorigenicity

The inhibitor of apoptosis protein (IAP) family can inhibit apoptosis induced by a variety of stimuli. We and others previously described the IAP Livin (ML-IAP). We found that Livin is unique among the IAP members as, on a strong apoptotic stimulus, it is specifically cleaved by caspases to produce a truncated protein with paradoxical proapoptotic activity (tLivin). We also showed that Livin encodes two splicing variants, termed Livin alpha and beta, with diverse antiapoptotic effects in vitro. In this study, we compared the Livin isoforms in vivo. An animal model was established and the effects of Livin alpha and beta on the initiation and development of tumors were compared. In the animal model, Livin alpha promotes tumor initiation in comparison with control. Interestingly, the growth of tumors originating from cells expressing Livin beta was inhibited. In these tumors, Livin beta was cleaved and produced a high level of the proapoptotic tLivin beta that repressed tumor development. When we eliminated the proapoptotic effect of Livin beta by point mutations, the resulting antiapoptotic Livin beta mutants contributed to tumor progression. In terms of mechanism, we show that Livin beta tumors develop only in mice lacking natural killer (NK) cell activity. Thus, from the animal model, we can conclude that Livin plays a major role in tumorigenicity and that NK cells induce cleavage of Livin to its proapoptotic truncated protein that in turn inhibits tumor growth. Therefore, Livin and tLivin may serve as potential targets for cancer therapy.