Livin/melanoma inhibitor of apoptosis protein as a potential therapeutic target for the treatment of malignancy

Livin promotes Th2-type immune response in airway allergic diseases

OBJECTIVES

To investigate the effects of livin on the Th2 immune response in airway allergic diseases (AAD) and explore the interaction among livin, GATA3, IL-4 in peripheral blood CD4+ T cells of AAD patients.

METHODS

WT mice and livin KO mice were developed for model of AAD. Th2 cell levels in the lung tissues and spleen were assessed by flow cytometry. Also, it was assessed in the culture after exposing to livin inhibitor (Lp-15); the protein and mRNA levels of livin, GATA3 and IL-4 in peripheral blood CD4+ T cells isolated from patients with or without AAD were measured by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. Finally, Co-immunoprecipitation (Co-IP) was employed to identify the interaction between livin and GATA3.

RESULTS

Compared with WT mouse, Th2 cell frequency in lung tissues and spleen was significantly decreased in livin KO mouse; after adding Lp-15, the differentiation from Naive CD4+T cells in spleen to Th2 cells was blocked; the protein and mRNA levels of livin, GATA3 and IL-4 in AAD group were higher than that in control group. The levels of livin were positively correlated with IL-4, and GATA3 was also positively correlated with IL-4 and livin. GATA3 was detected in the protein complex co-precipitated with livin antibody, and livin was also detected in the protein complex co-precipitated by GATA3 antibody.

CONCLUSION

Livin increases the expression of IL-4 and facilitates naive CD4+ T cells to differentiate into Th2 cells, which triggers airway allergy.

Manuka honey in combination with 5-Fluorouracil decreases physical parameters of colonspheres enriched with cancer stem-like cells and reduces their resistance to apoptosis

The aim of the present work was to evaluate the in vitro effect of Manuka honey and its combination with 5-Fu, the most common drug used in the treatment of colon cancer, on the morphological and physical parameters of colonspheres enriched with cancer stem-like cells deriving from HCT-116 colon adenocarcinoma cell line and on the apoptosis rate. Manuka honey, alone and more in combination with 5-Fu, reduced the weight, the diameter and mass density of the spheroids and induced apoptosis through the downregulation of many apoptosis inhibitors, including IAPs (Livin, Survivin, XIAP), IGFs (IGF-I, IGF-II and IGF-IR) and HSPs (HSP-27, HSP-60 and HSP-70). These results led to a reduction in the survival ability of cancer stem-like cells, as well as to a chemosensitizing effect of honey towards 5-Fu, considering that apoptosis resistance is one of the main causes of cancer stem-like cells chemoresistance.

The curcumin analog EF24 is highly active against chemotherapy-resistant melanoma cells

BACKGROUND

Malignant melanoma (MM) is an aggressive type of skin cancer with a poor prognosis, because MM cells are characterized by unresponsiveness to chemotherapy.

OBJECTIVE

In this study, we evaluated the effectiveness of several curcumin analogs on four MM cell lines (SK-MEL-28, MeWo, A-375, and CHL-1), and explored their underlying mechanisms of action.

METHODS

Cell viability was measured by a Tetrazolium-based MTS assay. Cell apoptosis, reactive oxygen species (ROS), and cell cycle were assayed by flow cytometry. Protein levels were assayed by western blotting.

RESULTS

MM cells are quite resistant to the conventional chemotherapeutics cisplatin and dacarbazine, and the targeted therapy drug vemurafinib. Among the curcumin analogs, EF24 is the most potent compound against the resistant MM cells. EF24 dose- and time-dependently reduced the viability of MM cells by inducing apoptosis. Although EF24 did not increase the production of reactive oxygen species (ROS), it upregulated the endoplasmic reticulum (ER) stress marker BiP, but downregulated the unfolded protein response (UPR) signaling. Moreover, treatment of MM cells with EF24 downregulated the expression of the anti-apoptotic protein Bcl-2, as well as the inhibitor of apoptosis proteins (IAPs) XIAP, cIAP1, and Birc7, which are known to protect MM cells from apoptosis. The downregulation of Bcl-2 and IAP expression by EF24 was associated with the inhibition of the NF-κB pathway.

CONCLUSION

These findings demonstrate that EF24 is a potent anti-MM agent. The anti-MM effect is likely mediated by the suppression of UPR and the NF-κB pathway.

BIRC7 and STC2 Expression Are Associated With Tumorigenesis and Poor Outcome in Extrahepatic Cholangiocarcinoma

Background:

Extrahepatic cholangiocarcinoma (EHCC) is a highly aggressive epithelial malignancy and has a poor prognosis for the insensitivity to therapies and difficulty in detection. Novel targets and biomarkers are urgently needed to develop for functional, diagnostic and prognostic application on EHCC.

Methods:

Immunohistochemical staining technique using the EnVision antibody complex was performed on the samples obtained from 100 EHCC, 30 peritumoral extrahepatic biliary tract (EHBT), 10 EHBT adenomas and 15 normal EHBT tissues.

Results:

The positive rates of BIRC7 and STC2 expression in tissues obtained from peritumoral EHBT, EHBT adenomas and normal EHBT were significantly lower than those in EHCC tissues. BIRC7 and STC2 proteins were expressed at significantly higher levels in patients with lymph node metastasis, invasion of adjacent tissues, and higher TNM stage (III and/or IV) and unable to undergo resection (biopsy only). Kaplan-Meier survival curves indicated that significantly decreased overall survival rate in patients with positive-BIRC7 or positive-STC2 expression compared with patients of negative-BIRC7 or negative-STC2 expression, respectively. Cox-proportional regression analysis demonstrated that positive-BIRC7 and positive-STC2 expression, along with poor differentiation of EHCC, tumor size >3 cm, lymph node metastasis, invasion of adjacent tissues and unable to undergo resection are independent prognostic factors of EHCC patients.

Conclusions:

The levels of BIRC7 and STC2 expression were correlated with clinicopathological characteristics of EHCC, and positive expression of BIRC7 and STC2 are associated with progression and poor clinical outcomes of EHCC. BIRC7 and STC2 might be a potential biomarker for EHCC in clinic.

Methylation-mediated miR-214 regulates proliferation and drug sensitivity of renal cell carcinoma cells through targeting LIVIN

LIVIN, a member of the inhibitor of apoptosis proteins (IAPs), is reported playing important roles in the development and progression of multiple human cancers. However, its underlined mechanisms in human renal cell carcinoma (RCC) are still needed to be clarified. In the present study, we reported that inhibition of miR-214 promoted the expression of LIVIN, then facilitated RCC cells growth and reduced the sensitivity of RCC cells to chemotherapeutic drugs. In constant, overexpression of miR-214 had contradictory effects. Further investigation showed that miR-214 was down-regulated in RCC because of abnormal methylation. In addition, DNA methyltransferase DNMT1, miR-214 and LIVIN are directly correlated in RCC patients. In conclusion, these results suggest that abnormal miR-214 methylation negatively regulates LIVIN, which may promote RCC cells growth and reduced the sensitivity of RCC cells to chemotherapeutic drugs.

Copper-imidazo[1,2-a]pyridines induce intrinsic apoptosis and modulate the expression of mutated p53, haem-oxygenase-1 and apoptotic inhibitory proteins in HT-29 colorectal cancer cells

Metastatic colorectal cancer responds poorly to treatment and is a leading cause of cancer related deaths. Worldwide, chemotherapy of metastatic colorectal cancer remains plagued by poor efficacy, development of resistance and serious adverse effects. Copper-imidazo[1,2-a]pyridines were previously shown by our group to be selectively active against several cancer cell lines, with three complexes, JD46(27), JD47(29), and JD88(21), showing IC₅₀ values between 0.8 and 1.8 μM against HT-29 cells. Here, we report that treatment with the copper complexes resulted in fragmented nuclei suggestive of apoptotic cell death, which was confirmed by increased annexin V binding and caspase-3/7 activity. The copper complexes caused a loss of mitochondrial membrane potential and increased caspase-9 activity. The absence of caspase-8 activity indicated activation of the intrinsic pathway. Proteomic analysis revealed that copper-imidazo[1,2-a]pyridines decreased the expression of phosphorylated forms of p53 [phospho-p53(S15), phospho-p53(S46) and phospho-p53(S392)]. The expression of inhibitor of apoptosis proteins, XIAP, cIAP1, livin, and the antiapoptotic proteins, Bcl-2 and Bcl-x, was decreased. HO/HMOX/HSP32, expression was notably increased, which suggested the accumulation of reactive oxygen species. Increased expression of TRAIL-R2/DR5 death receptor indicated the possible dual activation of both the extrinsic and intrinsic apoptotic pathways; however, caspase-8 activation could not be demonstrated. In conclusion, the copper-imidazo[1,2-a]pyridines were effective inducers of apoptotic cell death at low micromolar concentrations and changed the expression levels of proteins important for cell survival and cell death. These copper complexes may be useful tools to better understand the complexity of signalling networks in cancer cell death in response to cell stress.

Mannan oligosaccharide increases the growth performance, immunity and resistance capability against Vibro Parahemolyticus in juvenile abalone Haliotis discus hannai Ino

This trial was conducted to investigate the effect of mannose oligosaccharides (MOS) on the growth performance, antioxidation, immunity and disease resistance of Vibro Parahemolyticus in juvenile abalone Haliotis discus hannai Ino. Four formulated diets were produced to contain 0.00 g/kg, 0.40 g/kg, 0.80 g/kg and 1.60 g/kg Actigen®, with functional ingredients of MOS, respectively. Accordingly, the experimental diets were named as A0, A4, A8 and A16. After 120-days feeding trial, the best growth performance was observed in A8 group (P < 0.05) and there was no significant difference in A0, A4 and A16 groups. With the increase of dietary MOS, the activity of the total antioxidant capacity in hepatopancreas is increasingly elevated (P < 0.05) while no significant difference was observed on activity of glutathione S-transferase (P > 0.05). The activities of superoxide dismutase and glutathione peroxidase were firstly increased and then decreased, with the highest values in A8 group (P < 0.05). Immune-related parameters were significantly affected by dietary MOS inclusion. Specifically, the activities of alkaline phosphatase and acid phosphatase in hepatopancreas and serum of abalone fed diets containing MOS were significantly higher than those of control A0 group (P < 0.05). Moreover, the highest values of both enzymes were observed in hepatopancreas of A8 group but in serum of A16 group, respectively. The lysozyme activities in hepatopancreas and serum of A4 group were significantly higher than those of other groups (P < 0.05) and there was no significant difference in A0, A8 and A16 groups (P > 0.05). The activities of cytophagy and respiratory burst in serum of abalone were not significantly affected by dietary MOS content (P > 0.05). The mRNA levels of focal adhesion kinase and integrin-linked kinase were gradually elevated with the increase of dietary MOS, with the highest value recorded in A16 group (P < 0.05). The gene expression of caspse-3 in A8 group was dramatically higher than those of other groups (P < 0.05) and there was no significant difference in A0, A4 and A16 groups (P > 0.05). The mRNA level of nuclear factor-κB was not significantly affected by dietary MOS (P > 0.05). During 56 h of V. Parahemolyticus challenge period, the accumulated mortality rate of abalone fed diets containing MOS were significantly lower than that of control A0 group in each time point (P < 0.05). Overall, the lowest rate was happened in A8 group (P < 0.05). In conclusion, MOS inclusion in diet has obviously positive effect on growth, immunity and disease resistance capability of abalone, with the optimal level of Actigen® at 0.80 g/kg in diet.

High BIRC7 Expression Might Be an Independent Prognostic Indicator of Poor Recurrence-Free Survival in Patients With Prostate Cancer

Background:

BIRC7, which encodes Baculoviral inhibitor of apoptosis (IAP) repeat-containing protein 7, is an oncogene in multiple types of cancer. In this study, we examined the association between BIRC7 expression and the clinicopathological characteristics of prostate cancer, the independent prognostic value of BIRC7 in terms of recurrence-free survival, and the molecular mechanisms of its dysregulation.

Methods:

Data mining was performed using data from The Cancer Genome Atlas. The patients were divided into high and low BIRC7 expression groups according to the Youden index determined by receiver operating characteristic curves for recurrence. Subgroup analysis was performed according to T stages and Gleason score.

Results:

BIRC7 was significantly upregulated in prostate cancer tissues (N = 497) than in normal prostate tissues (N = 52). High BIRC7 expression group had lower ratios of overall response rate and medium-grade (Gleason score 6-7) tumors and higher proportions of nodal invasion and recurrence after surgery. Although Kaplan-Meier curves showed that high BIRC7 expression was generally associated with poor recurrence-free survival, the following subgroup analysis only confirmed the association in T3/T4 and medium-grade tumors. Multivariate analysis showed that BIRC7 expression was not an independent indicator of recurrence-free survival in T2 or high-grade tumors, but was independently associated with poor recurrence-free survival in T3/T4 tumors (hazard ratio: 4.249, 95% confidence interval: 1.563-11.546, P = .005) and in medium-grade tumors (hazard ratio: 6.041, 95% confidence interval: 1.763-20.703, P = .004). DNA amplification was associated with significantly upregulated BIRC7 expression. There was also a weak negative correlation between BIRC7 expression and its DNA methylation (Pearson r = −0.23).

Conclusion:

Based on these findings, we infer that BIRC7 upregulation might serve as a valuable biomarker of increased recurrence risk in advanced T stages and medium-grade prostate cancer. Its expression is at least regulated by both copy number alteration and DNA methylation.

SNIPERs-Hijacking IAP activity to induce protein degradation

The induction of protein degradation by chimeric small molecules represented by proteolysis-targeting chimeras (PROTACs) is an emerging approach for novel drug development. We have developed a series of chimeric molecules termed specific and non-genetic inhibitor of apoptosis protein (IAP)-dependent protein erasers (SNIPERs) that recruit IAP ubiquitin ligases to effect targeted degradation. Unlike the chimeric molecules that recruit von Hippel-Lindau and cereblon ubiquitin ligases, SNIPERs induce simultaneous degradation of IAPs such as cIAP1 and XIAP along with the target proteins. Because cancer cells often overexpress IAPs-a mechanism involved in the resistance to cancer therapy-SNIPERs could be used to kill cancer cells efficiently.

Inhibitors of apoptosis: clinical implications in cancer

Inhibitor of apoptosis (IAP) family comprises a group of endogenous proteins that function as main regulators of caspase activity and cell death. They are considered the main culprits in evasion of apoptosis, which is a fundamental hallmark of carcinogenesis. Overexpression of IAP proteins has been documented in various solid and hematological malignancies, rendering them resistant to standard chemotherapeutics and radiation therapy and conferring poor prognosis. This observation has urged their exploitation as therapeutic targets in cancer with promising pre-clinical outcomes. This review describes the structural and functional features of IAP proteins to elucidate the mechanism of their anti-apoptotic activity. We also provide an update on patterns of IAP expression in different tumors, their impact on treatment response and prognosis, as well as the emerging investigational drugs targeting them. This aims at shedding the light on the advances in IAP targeting achieved to date, and encourage further development of clinically applicable therapeutic approaches.

Concomitant modulation of PTEN and Livin in gastric cancer treatment

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Livin are important in the development of gastric cancer (GC). PTEN and Livin are involved in the regulation of tumor cell proliferation, migration and apoptosis. The modulation of PTEN or Livin has been investigated extensively in various cancer models. However, no studies have been performed to evaluate the combined effect of concurrently modulating these two genes on the development of GC. In the present study, the BGC823 human gastric carcinoma cell line was transfected with a dual gene modified vector (pCL-neo-PTEN-siLivin) in parallel with single gene modified vectors (pCL‑neo‑PTEN or pRNAT‑U6.1‑siLivin), and an empty control vector. Dual gene modulation (pCL‑neo‑PTEN‑siLivin) had a more marked effect on the inhibition of cell proliferation, induction of apoptosis, and reduction of cell penetration in Matrigel, compared with either single gene alone or empty vector transfection. In a xenograft nude mouse model, the inoculation of pCL‑neo‑PTEN‑siLivin‑transfected BGC823 cells led to a markedly reduced tumor burden, compared with that in all other inoculation groups. In conclusion, the overexpression of PTEN concomitant with Livin gene silencing was confirmed as a feasible and effective in vitro and in vivo gene modulation method, which may represent a potential therapeutic strategy for the treatment of GC.

Vitamin E Reversed Apoptosis of Cardiomyocytes Induced by Exposure to High Dose Formaldehyde During Mice Pregnancy

In this study, we investigated the protection effect of Vitamin E (Vit E) on formaldehyde (FA) exposure during pregnancy induced apoptosis of cardiomyocytes, and used an HL-1 cell line to confirmed the findings in vivo.Pregnant mice received different doses of FA (0.5 mg/kg, 1.0 mg/kg, 1.5 mg/kg, 0.1 μg Vit E, or 1.5 mg/kg + 0.1 μg Vit E). TUNEL staining was used to reveal the apoptosis in cardiomyocytes, and SOD, MDA, GSH, Livin, and Caspase-3 in cardiomyocytes were detected by ELISA, RT-PCR, and Western blot. For in vitro study, HL-1 cells were treated with vehicle, 5 μmol/L FA, 25 μmol/L FA, 50 μmol/L FA, 10 mg/L Vit. E, and 50 μmol/L FA+ 10 mg/L Vit E, respectively. CCK-8 assay and flow cytometry were used to evaluate cell vitality and apoptosis. A high dose of FA exposure led to cytotoxicity in both pregnant mice and offspring, as TUNEL staining revealed a significant apoptosis of cardiomyocytes, and the alternation in SOD, GSH, MDA, Livin, and Caspase-3 was found in cardiomyocytes. 0.1 μg Vit. E could reverse high doses of FA exposure induced apoptosis of cardiomyocytes in both pregnant mice and offspring. The in vitro study revealed that FA exposure induced a decrease of cell viability and increased cell apoptosis, as well as oxidative stress in HL-1 cells with alternation in SOD, GSH, MDA, Livin, and Caspase-3.This study revealed a high dose of FA induced oxidative stress and apoptosis of cardiomyocytes in both pregnant mice and offspring, and Vit E supplement during pregnancy reversed the systemic and myocardial toxicity of FA.

Immune surveillance in melanoma: From immune attack to melanoma escape and even counterattack

Pharmacologic inhibition of the cytotoxic T lymphocyte antigen 4 (CTLA4) and the programmed death receptor-1 (PD1) has resulted in unprecedented durable responses in metastatic melanoma. However, resistance to immunotherapy remains a major challenge. Effective immune surveillance against melanoma requires 4 essential steps: activation of the T lymphocytes, homing of the activated T lymphocytes to the melanoma microenvironment, identification and episode of melanoma cells by activated T lymphocytes, and the sensitivity of melanoma cells to apoptosis. At each of these steps, there are multiple factors that may interfere with the immune surveillance machinery, thus allowing melanoma cells to escape immune attack and develop resistance to immunotherapy. We provide a comprehensive review of the complex immune surveillance mechanisms at play in melanoma, and a detailed discussion of how these mechanisms may allow for the development of intrinsic or acquired resistance to immunotherapeutic modalities, and potential avenues for overcoming this resistance.

Molecular impact of selective NFKB1 and NFKB2 signaling on DLBCL phenotype

Diffuse large B-cell lymphoma (DLBCL) has been categorized into two molecular subtypes that have prognostic significance, namely germinal center B-cell like (GCB) and activated B-cell like (ABC). Although ABC-DLBCL has been associated with NF-κB activation, the relationships between activation of specific NF-κB signals and DLBCL phenotype remain unclear. Application of novel gene expression classifiers identified two new DLBCL categories characterized by selective p100 (NF-κB2) and p105 (NF-κB1) signaling. Interestingly, our molecular studies showed that p105 signaling is predominantly associated with GCB subtype and histone mutations. Conversely, most tumors with p100 signaling displayed ABC phenotype and harbored ABC-associated mutations in genes such as MYD88 and PIM1. In vitro, MYD88 L265P mutation promoted p100 signaling through TAK1/IKKα and GSK3/Fbxw7a pathways, suggesting a novel role for this protein as an upstream regulator of p100. p100 signaling was engaged during activation of normal B cells, suggesting p100's role in ABC phenotype development. Additionally, silencing p100 in ABC-DLBCL cells resulted in a GCB-like phenotype, with suppression of Blimp, IRF4 and XBP1 and upregulation of BCL6, whereas introduction of p52 or p100 into GC cells resulted in differentiation toward an ABC-like phenotype. Together, these findings identify specific roles for p100 and p105 signaling in defining DLBCL molecular subtypes and posit MYD88/p100 signaling as a regulator for B-cell activation.

Silencing the livin gene enhances the cytotoxic effects of anticancer drugs on colon cancer cells

Purpose

Livin is associated with drug response in several cancers. The aim of this study was to investigate the effect of silencing the livin gene expression on anticancer drug response in colorectal cancer.

Methods

siRNA was transfected at different concentrations (0, 10, and 30nM) into HCT116 cells, then cells were treated with either 5-fluorouracil (FU)/leucovorin (LV) or oxaliplatin (L-OHP)/5-FU/LV. Cellular viability and apoptosis were evaluated following silencing of livin gene expression combined with treatment with anticancer drugs.

Results

Livin gene expression was effectively suppressed by 30nM siRNA compared with control and 10nM siRNA. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay showed that proliferation was effectively inhibited in cells treated with a combination of both siRNA and an anticancer drug, compared to cells treated with siRNA-Livin or anticancer drug alone. In particular, the combination of 30nM siRNA and L-OHP/5-FU/LV resulted in a 93.8% and 91.4% decrease, compared to untreated control or L-OHP/5-FU/LV alone, respectively. Cellular proliferation was most effectively suppressed by a combination of 30nM of siRNA and L-OHP/5-FU/LV compared to other combinations.

Conclusion

siRNA-mediated down-regulation of livin gene expression could significantly suppress colon cancer growth and enhance the cytotoxic effects of anticancer drugs such as 5-FU and L-OHP. The results of this study suggest that silencing livin gene expression in combination with treatment with anticancer drugs might be a novel cancer therapy for colorectal cancer.

Overexpression of Livin promotes migration and invasion of colorectal cancer cells by induction of epithelial-mesenchymal transition via NF-κB activation

Livin is a novel member of the inhibitors of apoptosis protein family and has been implicated in the development and progression of colorectal cancer (CRC). However, the underlying mechanisms of Livin in CRC remain not fully understood. In this study, we investigated the effects of Livin expression on the proliferation and metastasis of CRC cells and also addressed its related molecular mechanism to metastasis. The expression of Livin in CRC cells (HCT116, SW480, and HT-29 cell lines) was determined by Western blot analysis. Our results show that the overexpression of Livin significantly promotes the proliferation, migration, and invasion of SW480 cells. Concurrently, the inhibition of Livin reduces the proliferation, migration, and invasion of HCT116 cells. In addition, Livin overexpression promotes the epithelial–mesenchymal transition, as evidenced by a decrease in epithelial E-cadherin expression and an increase in mesenchymal markers, including vimentin, Slug, and Snail. Furthermore, adding the NF-κB inhibitor, BAY 11-7028, or transfecting with small interfering RNA against p65 notably restores the expression level of E-cadherin and attenuates the invasive ability of Livin-overexpressing cells. Taken together, these results indicate that Livin potentiates migration and invasion of CRC cells partially through the induction of epithelial–mesenchymal transition via NF-κB activation. Livin may be a potential therapeutic target for CRC.

Piperine derivatives as potential inhibitors of Survivin: An in silico molecular docking

Targeting Survivin, as an inhibitor of apoptosis and a regulator of cell division, has become a worldwide controversial issue. Piperine as a pungent alkaloid has been identified as the most potent adjuvant at enhancing the efficacy of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-based therapies in triple-negative breast cancer (TNBC) cells in vitro and in vivo, which might be mediated through inhibition of Survivin. In this work, the binding energies, inhibition constants and binding modes of a group of previously synthesized Piperine derivatives at the binding site of Survivin have been studied using molecular docking tools and the best compounds with minimum binding energies are proposed as potential drugs for the inhibition of Survivin. A comprehensive SAR analysis has been done on the results that can be used for designing new Piperine analogs with higher efficacy. Molecular docking computations also show that the studied compounds can bind to BIR domain of Survivin in the same binding site as that of Smac/DIABLO with a suitable binding energy. This binding may result in the segregation of Smac/DIABLO in the cytosol and subsequently free Smac/DIABLO molecules could be available for binding with inhibitors of apoptosis to initiate caspase mediated apoptosis.

Livin is associated with the invasive and oncogenic phenotypes of human hepatocellular carcinoma cells

AIM

Livin, a member of the inhibitors of apoptosis proteins, is expressed in variable cancers, and its expression is considered a poor prognostic marker. The aims of this study were to observe the effect of Livin on the behaviors of hepatocellular carcinoma (HCC) cells and to evaluate its expression in HCC tissues and its relation to prognosis.

METHODS

The biological effects of Livin on tumor cell behavior were investigated using siRNA in HepG2 and Chang cells. Migration, invasion and proliferation assays were performed. Flow cytometric analyses and western blotting were used to evaluate the impact of Livin on apoptosis and the cell cycle. In addition, western blotting and immunohistochemistry were used to investigate Livin expression in HCC tissues.

RESULTS

Livin knockdown suppressed tumor cell migration, invasion and proliferation in HCC cells, and increased the proportion of apoptotic cells as compared with scrambled siRNA-transfected HCC cells. Furthermore, Livin knockdown resulted in the activation of caspases and increased apoptosis. In addition, Livin knockdown modulated cell cycle regulatory protein levels such as decrease of cyclins and cyclin-dependent kinase (CDK) level, and increase of CDK inhibitor (CDKI) level in HCC cells. The Livin protein level was significantly elevated in HCC tissues as compared with normal hepatic tissues. However, Livin expression was not found to be associated with clinicopathological parameters, which included patient survival.

CONCLUSION

These results suggest that Livin is associated with invasive and oncogenic phenotypes of human HCC cells.

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.

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.

Differential expression of Livin, caspase-3, and second mitochondria-derived activator of caspases in chronic rhinosinusitis with nasal polyps

BACKGROUND AND OBJECTIVES

The pathogenesis of human chronic rhinosinusitis with nasal polyps (CRSwNP) remains undetermined. Livin is a member of the inhibitor of the apoptosis protein family proteins. Caspase-3 and second mitochondria-derived activator of caspases (Smac) are critical in the induction of apoptosis. However, little is known about their roles in CRSwNP. We aimed to investigate the expression and role of Livin, caspase-3, and Smac in CRSwNP.

STUDY DESIGN

Basic research and descriptive study.

SETTING

Fuzhou General Hospital, Fuzhou, Fujian, China.

METHODS

The immunohistochemistry method was employed for detecting Livin, caspase-3, and Smac protein expression, and real-time polymerase chain reaction was used for assaying mRNA expression of Livin, caspase-3, and Smac in CRSwNP and controls. Moreover, the effects of various stimulators on Livin were evaluated on human nasal epithelial cells (HNECs) culture. Then, the effects of Livin on caspase-3 and Smac were observed on the culture of HNECs.

RESULTS

Stronger protein and mRNA expression of Livin was observed in CRSwNP, especially eosinophilic CRSwNP, weaker protein and mRNA expression of caspase-3 and Smac was observed in CRSwNP, and Livin expression was negatively related to caspase-3 or Smac expression, respectively. Livin mRNA was augmented by interleukin (IL)-4, IL-17A, and IL-1β but suppressed by interferon-γ. Caspase-3 and Smac mRNA expression were inhibited by Livin.

CONCLUSIONS

Upregulation of Livin and downregulation of caspase-3 and Smac were observed in CRSwNP, especially in eosinophilic CRSwNP. Livin may exert its anti-apoptosis effect by suppressing caspase-3 and Smac in CRSwNP. IL-4, IL-17A, and IL-1β may be critical for Livin expression.

Prospective experimental studies on the renal protective effect of ulinastatin after paraquat poisoning

BACKGROUND

Paraquat (PQ) is an effective herbicide and is widely used in agricultural production, but PQ poisoning is frequently seen in humans with the lung as the target organ. Currently, there are many studies on lung injury after PQ poisoning. But the kidney as the main excretory organ after PQ poisoning is rarely studied and the mechanisms of this poisoning is not very clear. In this study, we observed the expression of caspase-3 and livin protein in rat renal tissue after PQ poisoning as well as the therapeutic effects of ulinastatin.

METHODS

Fifty-four Sprague-Dawley (SD) rats were randomly divided into three experimental groups: control group (group A), paraquat poisoning group (group B) and ulinastatin group (group C), with 18 rats in each group. Rats in group B and group C were administered intragastrically with 80 mg/kg PQ, rats in group C were injected peritoneally with 100 000 U/kg ulinastatin once a day, while rats in group A were administered intragastrically with the same volume of saline as PQ. At 24, 48, 72 hours after poisoning, the expression of livin in renal tissue was detected by Westen blotting, the expression of caspase-3 was detected by immunohistochemistry, and the rate of renal cell apoptosis was tested by TUNEL detection. The histopathological changes were observed at the same time.

RESULTS

Compared to group A, the expression of caspase-3 in the renal tissue of rats in groups B and C increased significantly at any time point. Compared with group B, the expression of caspase-3 in renal tissue of rats in group C decreased. Compared with group A, the expression of livin in renal tissue in rats of groups B and C increased significantly at any time point (P<0.01), especially in group C (P<0.01). TUNEL method showed that the rate of renal cell apoptosis index was higher in group B at corresponding time points than in group A (P<0.01), and was lower in group C at corresponding time points than in group B (P<0.01).

CONCLUSION

UTI has a protective effect on the renal tissue of rats after paraquat poisoning through up-regulating the expression of livin and down-regulating the expression of caspase-3, but the regulation path still needs a further research.

Expression and prognostic significance of livin, caspase-3, and ki-67 in the progression of human ampullary carcinoma

Livin is a new member of the inhibitor of apoptosis proteins family of proteins that interacts with downstream caspases, such as caspase-3, caspase-7, and caspase-9, however, its role in human ampullary carcinoma has not been clearly defined. Immunohistochemistry was used to evaluate tissue samples from patients with ampullary carcinomas (n=71) using antibodies against livin, Ki-67 (a proliferation marker), and caspase-3. Livin was detected in 33/71 cases (in the cytoplasm of all and in the nucleus of only 2 cases). High livin expression correlated with cell differentiation, tumor-node-metastasis stage, and lymph node metastasis (P=0.001, P<0.001, and P=0.028, respectively). Caspase-3 and Ki-67 expression were significantly associated with differentiation (P<0.001, P=0.008, respectively). There was a significant negative correlation between livin and caspase-3 (r=-0.575, P<0.001), and a positive correlation between livin and Ki-67 (r=0.308, P=0.009). Survival of patients with high livin expression was shorter compared with that of patients with low livin expression (P=0.001). Expression of caspase-3 was not associated with overall survival in this cohort (P=0.335). Livin expression was an independent prognostic factor (hazard ratio 2.693, P=0.017), as was lymph node metastasis (hazard ratio 4.959; P<0.001). In this study livin expression significantly correlated with the proliferation marker Ki-67, but was negatively correlated with caspase-3 expression. These data suggest that livin may be a valuable prognostic factor for human ampullary carcinoma.

Chalcones with electron-withdrawing and electron-donating substituents: anticancer activity against TRAIL resistant cancer cells, structure-activity relationship analysis and regulation of apoptotic proteins

In the present study, a series of 46 chalcones were synthesised and evaluated for antiproliferative activities against the human TRAIL-resistant breast (MCF-7, MDA-MB-231), cervical (HeLa), ovarian (Caov-3), lung (A549), liver (HepG2), colorectal (HT-29), nasopharyngeal (CNE-1), erythromyeloblastoid (K-562) and T-lymphoblastoid (CEM-SS) cancer cells. The chalcone 38 containing an amino (-NH2) group on ring A was the most potent and selective against cancer cells. The effects of the chalcone 38 on regulation of 43 apoptosis-related markers in HT-29 cells were determined. The results showed that 20 apoptotic markers (Bad, Bax, Bcl-2, Bcl-w, Bid, Bim, CD40, Fas, HSP27, IGF-1, IGFBP-4, IGFBP-5, Livin, p21, Survivin, sTNF-R2, TRAIL-R2, XIAP, caspase-3 and caspase-8) were either up regulated or down regulated.

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.

Knockdown of Livin inhibits growth and invasion of gastric cancer cells through blockade of the MAPK pathway in vitro and in vivo

Livin, a novel member of the human inhibitors of apoptosis protein family, has been shown to be critical for tumor progression and poor prognosis for several types of malignancies. However, limited reports exist regarding the biological functions of Livin in human gastric cancer (GC). The present study investigated the clinical significance of Livin and caspase-3 (CAS-3) in human GC using immunohistochemistry assay, and explore the potential using RNA interference to knockdown Livin expression, including the subsequent effects on tumor growth and invasion in GC cells in vitro and in vivo. Our results showed that the rate of positive expression of Livin was significantly higher in GC tissues compared to that in adjacent non-cancer tissues (ANCT) (64.1 vs. 30.8%, P<0.001), while CAS-3 was lower in GC tissues than in ANCT (33.3 vs. 66.7%, P=0.001). Livin expression was positively correlated with tumor differentiation and lymph node metastases (P=0.009; P=0.007), while CAS-3 was negatively correlated with them (P=0.036; P=0.002) in patients with GC. Furthermore, knockdown of Livin inhibited cell proliferative activities and invasive potential, and induced cell in situ apoptosis in GC cells, accompanied with decreased expression of p38 MAPK, VEGF and MMP-2 and increased expression of CAS-3. In addition, the tumor volumes in the SGC7901 subcutaneous nude mouse model treated with Lv-shLivin was significantly smaller compared to those of the PBS group (P<0.01). Taken together, our findings indicate that the expression of Livin is increased in human GC and correlates with tumor differentiation and lymph node metastases, while knockdown of Livin inhibits cell growth and invasion through blockade of the MAPK pathway in GC cells, suggesting that Livin may be a potential therapeutic target for the treatment of GC.

Expression and prognostic significance of Livin in gastric cancer

Livin is one of the most important members of the inhibitor of apoptosis protein family. It is overexpressed in several types of tumors and may have prognostic significance. The present study investigated the biological role of Livin in the oncogenic behavior of gastric cancer cells, the expression of Livin in gastric cancer tissue and the relationship of its expression with various clinicopathological parameters and patient survival. Small interfering RNA blocked Livin gene expression in AGS and SNU638 human gastric cancer cell lines. The expression of Livin was investigated in gastric cancer tissues by RT-PCR, western blotting and immunohistochemistry. The associations with various clinicopathological parameters and survival were analyzed. Livin knockdown inhibited tumor cell migration, invasion and proliferation in AGS and SNU638 cells. Livin knockdown induced apoptosis by activating caspase-3, caspase-7 and PARP. Livin knockdown induced cell cycle arrest by a decrease in cyclin D1, cyclin-dependent kinase 4 and 6 and an increase in expression of p21 and p27. The ERK1/2 and JNK signaling pathways were inhibited by Livin knockdown. Livin expression was upregulated in gastric cancer tissues at the mRNA and protein levels. However, no significant correlation was found between Livin expression and various clinicopathological parameters including survival. In conclusion, Livin expression may be important in the alteration of invasive and oncogenic phenotypes of gastric cancer cells. The prognostic relevance of Livin remains unclear.

Expression of Livin in colorectal cancer and its relationship to tumor cell behavior and prognosis

BACKGROUNDS

Expression of Livin, a member of the inhibitors of apoptosis protein family, is associated with tumor development and progression. The aims of this study were to evaluate whether Livin affects oncogenic biological behavior of colorectal cancer cells, and to document the relationship between its expression and various clinicopathological parameters in colorectal cancer.

METHODS

We investigated the impact of Livin on tumor cell behavior by using the small interfering RNA and pcDNA3.1 vector in SW480 and DKO1 colorectal cancer cell lines. The expression of Livin was investigated by RT-PCR and immunohistochemistry in coloretcal cancer tissues. The apoptotic cells were visualized by TUNEL assay, and proliferative cells were visualized by Ki-67 antibody staining.

RESULTS

Knockdown of Livin suppressed tumor cell migration and invasion in colorectal cancer cells. Knockdown of Livin induced the apoptosis by up-regulating of caspase-3, -7 and PARP activities and the cell cycle arrest by decreasing cyclin D1, cyclin D3, cyclin-dependent kinase 4 and 6, and by inducing p27 expression. The MAPK signaling cascades were significantly blocked by knockdown of Livin. In contrast, overexpression of Livin enhanced tumor cell migration and invasion, and inhibited the apoptosis and cell cycle arrest. The mean apoptotic index (AI) value of Livin positive tumors was significantly lower than AI of Livin negative tumors. However, there was no significant difference between Livin expression and Ki-67 labeling index (KI). Livin expression was significantly increased in colorectal cancer and metastatic lymph node tissues compared to normal colorectal mucosa and non-metastatic lymph node tissues and was associated with tumor stage, lymphovascular invasion, lymph node metastasis and poor survival.

CONCLUSIONS

These results indicate that Livin is associated with tumor progression by increasing tumor cell motility and inhibiting apoptosis in colorectal cancer.

RNA interference-mediated knockdown of Livin suppresses cell proliferation and invasion and enhances the chemosensitivity to cisplatin in human osteosarcoma cells

Livin is a novel member of the inhibitor of apoptosis protein (IAP) family that has been reported to be overexpressed in a variety of human malignancies, including osteosarcoma. However, the potential roles of Livin in tumorigenesis have not been elucidated. In the present study, we employed RNA interference (RNAi) technology to suppress endogenous Livin expression in osteosarcoma cells and successfully generated a U2-OS cell line with stably knockdown of Livin. Functional analysis showed that knockdown of Livin significantly reduced cell proliferation, colony formation, and invasion and migration capacities of U2-OS cells in vitro. Moreover, specific downregulation of Livin led to cell cycle arrest at the G0/G1 phase and eventual apoptosis. Meanwhile, western blot analysis revealed that cells with stably knockdown of Livin showed decreased expression levels of Cyclin D1, Bcl-2, matrix metalloproteinase (MMP)-2 and MMP-9, but increased expression levels of activated Caspase-3, Bax and cleaved poly (ADP-ribose) polymerase (PARP) compared to those transfected with a control vector. We also observed that suppression of Livin expression in osteosarcoma cells increased their chemosensitivity to cisplatin. Taken together, our data suggest that Livin is involved in tumorigenesis of human osteosarcoma and may serve as a promising therapeutic target for osteosarcoma.

Inhibition of Jak-STAT3 pathway enhances bufalin-induced apoptosis in colon cancer SW620 cells

Background

The purpose of the research is to investigate the roles of Jak-STAT3 signaling pathway in bufalin-induced apoptosis in colon cancer SW620 cells.

Methods

The inhibitory effects of bufalin on cell proliferation were determined by MTT (Methyl thiazolyltetrazolium) assay. The morphological changes of cells were measured by Wright-Giemsa staining. The cell cycle arrest and apoptosis were tested by flow cytometry analysis. Western Blot was used to determine the protein expression of the apoptosis inhibitors livin and caspase-3, the apoptosis-related proteins Bax and Bcl-2, as well as the key protein kinases in the Jak-stat3 signaling pathway, stat3 and p-stat3.

Results

(1) Bufalin inhibited the proliferation of SW620 cells. IC50 at 24 h, 48 h and 72 h were 76.72 ± 6.21 nmol/L, 34.05 ± 4.21 nmol/L and 16.7 ± 6.37 nmol/L. (2) Bufalin induced SW620 cell cycle arrest and apoptosis, indicated by the appearance of apoptotic bodies; (3) The results from flow cytometry demonstrated that there was cell cycle G2/M phase arrest in 20 nmol/L bufalin treatment group (36.29 ± 2.11% vs 18.39 ± 1.74%, P<0.01); there was a sub-diploid apoptosis peak in 80 nmol/L bufalin treatment group (19.69 ± 1.63% vs 0.99 ± 0.23%, P <0.01). The apoptosis rate was 34.63 ± 2.57% (vs 19.69 ± 1.63%, P = 0.002) in JAK kinase inhibitor AG490 plus bufalin treatment group. (4) During the process of bufalin-induced apoptosis in SW620 cells, transient activation of p-stat3 inhibited the activation of stat3, up-regulated Bax expression, down-regulated livin and Bcl-2 expression (P<0.01), and activated caspase-3. Inhibition of Jak-stat3 signaling pathway by pre-treatment with AG490 significantly enhanced the bufalin-induced apoptosis (P<0.01), further up-regulated Bax protein expression, down-regulated livin and Bcl-2 protein expression and enhanced caspase-3 activation.

Conclusions

Bufalin not only inhibited the growth of colon cancer SW620 cells, but also induced apoptosis of SW620 cells. Activation of caspase-3, up-regulation of Bax, down-regulation of livin and Bcl-2, as well as inhibition of Jak-stat3 signaling pathway might be the important mechanisms for the bufalin-induced apoptosis.

In vitro and in vivo antitumoral action of metformin on hepatocellular carcinoma

AIMS

  Metformin is a biguanide that has been widely used to treat type 2 diabetes. Several studies have shown that metformin is also effective in treating cancer, including hepatocellular carcinoma (HCC). The objective of this study was to evaluate the antitumor effects of metformin in HCC, and to investigate the potential molecular target(s) of metformin-mediated antitumor activity.

METHODS

  The antiproliferative effects of metformin were assessed in human HCC cell lines and normal human liver cells at various concentrations. Orthotopic xenograft tumors were established in athymic nude mice, and tumor growth was monitored after metformin treatment. Western blot analysis and cell cycle regulation were performed to determine the involvement of various mediators of apoptosis.

RESULTS

  Metformin specifically inhibited the growth of HCC cells without affecting the growth of normal liver cells both in vitro and in vivo. Metformin caused cell cycle arrest in HCC cells, which resulted in caspase-3 activation. Livin levels decreased in a dose-dependent manner upon metformin treatment. Metformin activated 5'-adenosine monophosphate-activated protein kinase, inhibited the mammalian target of rapamycin pathway and downregulated Livin protein expression.

CONCLUSION

  Our findings indicate that metformin is effective at initiating apoptosis and inhibiting key survival signaling pathways in HCC cells. These data provide a foundation for further studies to evaluate metformin in the clinic either as a single agent or in combination with other first-line agents as a treatment option for HCC.

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.

Livin regulates prostate cancer cell invasion by impacting the NF-κB signaling pathway and the expression of FN and CXCR4

Prostate cancer (PCa) has the second highest mortality rate of all tumor-related diseases for males in Western countries, and the incidence of PCa in China is increasing. Previous studies have proven that inhibitor of apoptosis proteins (IAPs) can regulate tumor cell invasion and metastasis. Livin is the most recently identified IAP. Our previous study showed that Livin might play an important role in the initiation of human PCa and that Livin-α might promote cell proliferation by regulating the G1-S cell cycle transition. However, whether Livin, as an IAP, can regulate the invasive ability of PCa cells remains unknown. In this study, we found that the expression of Livin was higher in metastatic PCa tissues than in nonmetastatic tissues and that the expression of Livin was downregulated/upregulated by small interfering RNA/vector, which could inhibit/promote PC-3/LNCaP cell invasion. This action was related to the impact of Livin on nuclear factor-κB (NF-κB) and its downstream signaling pathway, including FN and CXCR4. Together, our findings suggested that Livin might regulate tumor cell invasion in PCa directly, and that Livin might be an ideal candidate for preventing tumor cell invasion.

Molecular Network Associated with MITF in Skin Melanoma Development and Progression

Various environmental and genetic factors affect the development and progression of skin cancers including melanoma. Melanoma development is initially triggered by environmental factors including ultraviolet (UV) light, and then genetic/epigenetic alterations occur in skin melanocytes. These first triggers alter the conditions of numerous genes and proteins, and they induce and/or reduce gene expression and activate and/or repress protein stability and activity, resulting in melanoma progression. Microphthalmia-associated transcription factor (MITF) is a master regulator gene of melanocyte development and differentiation and is also associated with melanoma development and progression. To find better approaches to molecular-based therapies for patients, understanding MITF function in skin melanoma development and progression is important. Here, we review the molecular networks associated with MITF in skin melanoma development and progression.

Cdk2 acts upstream of mitochondrial permeability transition during paclitaxel-induced apoptosis

Sequential activation of cyclin-dependent kinases (Cdks) controls mammalian cell cycle. Here we demonstrate that the upregulation of cyclin-dependent kinase 2 (Cdk2) activity coincides with the loss of mitochondrial membrane potential (MMP) in paclitaxel-induced apoptosis. Ectopic expression of the dominant negative Cdk2 (Cdk2-dn) and a specific Cdk2 inhibitor, p21( WAF1/CIP1 ), effectively suppresses the loss of MMP, the release of cytochrome c, and subsequent activation of caspase-3 in paclitaxel-treated cells. Whereas forced activation of Cdk2 by overexpression of cyclin A dramatically promotes these events. We further show that Cdk2 activation status does not interfere with a procedure that lies downstream of cytochrome c release induced by Bax protein. These findings suggest that Cdk2 kinase can regulate apoptosis at earlier stages than mitochondrial permeability transition and cytochrome c release.

Livin-α promotes cell proliferation by regulating G1-S cell cycle transition in prostate cancer

BACKGROUND

Prostate cancer is the third most common cancer and the second leading cause of cancer death for males in US. Livin has recently been described as a cancer-associated member of inhibitor of apoptosis proteins family, highly expressed in prostate cancer. Livin gene encodes two splicing variants, termed Livin-α and Livin-β. We hypothesized that deregulation of proliferation could be due in part to Livin expression.

METHODS

Pathological analysis of Livin was performed in 20 prostate cancer tissues and 5 benign prostatic hyperplasia tissues. The expression of Livin isoforms was also investigated by Western blot in prostate cancer cell lines LNCaP and PC3. The role of Livin-α in vitro was further studied. Using Livin-α knockdown and overexpression models, cell cycle analysis, Ki-67 immunocytostaining, and MTT assay were performed respectively.

RESULTS

Livin expression positive ratio was shown to be 5.4%, 23.6%, 52.4%, 73.4% in benign prostatic hyperplasia, low, medium, and high grade of prostate cancer respectively, and Livin was positively correlated with clinical pathological grades of prostate cancer. Livin-α was expressed in both LNCaP and PC3; meanwhile; Livin-β was only detected in the PC3. Livin-α siRNA not only resulted in G(1)-S cell cycle arrest, but also strongly correlated with the descended proliferation index and survival rate in LNCaP. In comparison, overexpression of Livin-α resulted in an accelerated S phase entry combined with elevated proliferation index and survival in LNCaP.

CONCLUSIONS

Livin-α may promote cell proliferation by regulating G(1)-S cell cycle transition and possibly play an important part in initiation of prostate cancer.

DHA alters expression of target proteins of cancer therapy in chemotherapy resistant SW620 colon cancer cells

Diets rich in n-3 polyunsaturated fatty acids (PUFAs) have been associated with a reduced risk of several types of cancer. Recent reports have suggested that these PUFAs enhance the cytotoxic effect of cancer chemoradiotherapy. The effect of docosahexaenoic acid (DHA) on key cell cycle regulators and target proteins of cancer therapy was investigated in the human malign colon cancer cell line SW620. Cell cycle check point proteins such as p21 and stratifin (14-3-3 sigma) increased at mRNA and protein level, whereas cell cycle progression proteins such as cell division cycle 25 homolog and cyclin-dependent kinase 1 decreased after DHA treatment. Protein levels of inhibitors of apoptosis family members associated with chemotherapy resistance and cancer malignancy, survivin and livin, decreased after the same treatment: likewise the expression of NF-kappaB. Levels of the proapoptotic proteins phosphorylated p38 MAPK and growth arrest-inducible and DNA damage-inducible gene 153/C/EBP-homologous protein (CHOP) increased. The results indicate that DHA treatment causes simultaneous cell cycle arrest in both the G1 and G2 phase. In conclusion, DHA affects several target proteins of chemotherapy in a favorable way. This may explain the observed enhanced chemosensitivity in cancer cells supplemented with n-3 PUFAs and encourage further studies investigating the role of n-3 PUFAs as adjuvant to chemotherapy and radiotherapy in vivo.

Expression and functional role of inhibitor-of-apoptosis protein livin (BIRC7) in neuroblastoma

We evaluated the expression of the inhibitor-of-apoptosis protein (IAP)livin (BIRC7)in 59 cases ofneuroblastoma (NBL) by quantitative RT-PCR. We also examined the role of livin in protecting tumor cells from chemotherapy drugs. Livin expression varied significantly amongtumors. High levels of expression were observed in 17 of 39 patients with advanced stages (stages 3 and 4) and 6 of 20 patients with localized stages (stages 1 and 2). Livin-transfected, MYCN-amplified NBL cells showed increased resistance to doxorubicin and etoposide. Conversely, livin knockdown with siRNA enhanced spontaneous and drug-induced apoptosis in NBL cells. Multivariate analysis of prognostic factors showed that high livin expression worsened prognosis for patients with MYCN-amplified tumors. Our data suggest that (i) livin is frequently expressed in NBL and protects tumor cells with amplified MYCN oncogene from genotoxic agents; (ii) the antiapoptotic effect of livin in NBL is blocked by siRNA; (iii) in the sample studied, high livin expression enhanced the adverse prognostic impact of MYCN amplification. These findings suggest that livin may contribute to drug resistance in NBL.

Antisense oligonucleotide targeting Livin induces apoptosis of human bladder cancer cell via a mechanism involving caspase 3

BACKGROUND AND AIM

in recent years, Livin, a new member of IAPs family, is found to be a key molecule in cancers. Researchers consider Livin may become a new target for tumor therapy; however, the role of it in bladder cancer is still unclear. The purpose of this article is to investigate Antisense Oligonucleotide (ASODN) of Livin on treating bladder cancer cell and underlying mechanisms.

METHODS

Phosphorathioate modifying was used to synthesize antisense oligonucleotides targeting Livin, followed by transfection into human bladder cancer cell 5637. After transfection, Livin mRNA and protein level, cell proliferation and apoptosis changes, caspase3 level and its effect on human bladder cancer transplantable tumor in nude mice were measured.

RESULT

results showed Livin ASODN effectively inhibited Livin expression and tumor cell proliferation, and these effects probably through enhanced caspase3 activity and apoptosis of tumor cells. In nude mice transplantable tumor model, Livin expressions were inhibited meanwhile caspase3 expression was increased. Tumor growth slowed down and apoptosis was enhanced.

CONCLUSION

Our data suggest that Livin plays an important role in inhibiting apoptosis of bladder cancer cells. Livin ASODN may promote cell apoptosis, inhibit bladder cancer growth, and become one of the methods of gene therapy for bladder cancer.

Isolation of peptides blocking the function of anti-apoptotic Livin protein

Livin (ML-IAP) is a cancer-associated member of the inhibitor of apoptosis protein (IAP) family. By yeast two-hybrid screening of a randomized peptide expression library, we isolated short linear peptides that specifically bind to Livin, but not to other IAPs. Intracellular expression of the peptides sensitized livin-expressing cancer cells toward different pro-apoptotic stimuli. The bioactive peptides neither showed sequence homologies to Smac-derived IAP inhibitors, nor did they interfere with the binding of Livin to Smac. Intracellular expression of the peptides did not affect the levels or the subcellular distribution of Livin. Growth of livin-expressing tumor cells was inhibited in colony formation assays by the Livin-targeting peptides. These findings provide evidence that the targeted inhibition of Livin by peptides represents a viable approach for the apoptotic sensitization and growth inhibition of tumor cells. The inhibitory peptides isolated here could form a novel basis for the development of therapeutically useful Livin inhibitors.

Expression of inhibitor of apoptosis protein Livin in gastric cancer and adjacent non-cancerous tissue

AIM: To detect the expression of Livin protein in gastric cancer and adjacent non-cancerous tissue, and to analyze its prognostic significance by exploring the relationship between Livin expression and the biological behavior of gastric cancer.

METHODS: The expression of Livin was detected by immunohistochemistry (streptavidin-peroxidase method) in 50 gastric cancer and matched adjacent non-cancerous tissue samples. Quantitative analysis of Livin expression was performed with the Image-Pro Plus 6.0 software. The significance of Livin expression in gastric cancer was then analyzed.

RESULTS: The integrated absorbance (IA) value of Livin staining in gastric cancer tissue was significantly higher than that in adjacent non-cancerous tissue (283 270.55 ± 199 604.16 vs 6 878.08 ± 9 214.56, P < 0.01). The IA value was lower in well and moderately differentiated cancer tissue than in poorly and undifferentiated tissue (41 288.94 ± 27 891.09 vs 359 690.5 ± 166 583.17, P < 0.01), in cancer tissue not invading the serosal layer than in that invading the serosal layer (T_3-4) (85 529.62 ± 115 287.42 vs 360 174.77 ± 170 507.09, P < 0.01), and in gastric cancer without lymph node metastasis than in that with lymph node metastasis (148 547.51 ± 152 479.47 vs 380 949.72 ± 171 073.92, P < 0.01).

CONCLUSION: Livin protein is highly expressed in gastric cancer. Livin expression is significantly associated with tumor differentiation, infiltration and lymph node metastasis in gastric caner. Livin protein may be used as a prognostic marker for gastric cancer.

Influence of Etoposide on anti-apoptotic and multidrug resistance-associated protein genes in CD133 positive U251 glioblastoma stem-like cells

It has been hypothesized that cancer stem cell is responsible for the refractoriness of glioblastoma therapy. This study is to observe the influence of Etoposide on anti-apoptotic and multidrug resistance-associated protein genes in glioblastoma stem-like cells. U251 glioblastoma cells were cultured and CD133 positive cancer stem-like cells were isolated and identified. Cell counting kit-8 assay, cell morphology and flow cytometry were employed for assaying cell survival condition. Real-time quantitative PCR was chosen for detecting mRNA expression of livin, livinalpha, livinbeta, survivin, MRP1 and MRP3. As results, after Etoposide intervention, the U251 stem-like cells showed more resistant property, more intact morphology and lower apoptotic rate than that in U251 cells (p<0.05). It could be found that the expression of livinbeta in U251 stem-like cells was significantly higher (p<0.05). After Etoposide intervention, only livinalpha was suppressed markedly (p<0.05), while livin expression was not notably decreased with livinbeta increased on the contrary (p<0.05). MRP1 and MRP3 in U251 stem-like cells were significantly higher than that in cancer cells, and after chemotherapy, the expression of MRP1 increased notably (p<0.05). But the expression of survivin and MRP3 did not show these features. In conclusion, after Etoposide intervention glioblastoma stem-like cells showed a stronger resistance to apoptosis and death, and the anti-apoptotic gene livinbeta was more related with the high survival rate and MRP1 appeared to be more related with transporting chemotherapeutics out of glioblastoma stem-like cells.

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.