Expression Of cIAP2 Research Articles

Regulation of pro-apoptotic and anti-apoptotic factors in obesity-related esophageal adenocarcinoma

BackgroundObesity is a risk factor for esophageal adenocarcinoma (EAC). It was reported that obesity -associated inflammation correlates with insulin resistance and increased risk of EAC. The objective of the study is to investigate the role of obesity associated inflammatory mediators in the development of EAC.MethodsWe included 23 obese and nonobese patients with EAC or with or without Barrett’s esophagus (BE) after IRB approval. We collected 23 normal, 10 BE, and 19 EAC tissue samples from endoscopy or esophagectomy. The samples were analyzed for the expression levels of pro-apoptotic and anti-apoptotic factors, PKC-δ, cIAP2, FLIP, IGF-1, Akt, NF-kB and Ki67 by immunofluorescence and RT-PCR. We compared the expression levels between normal, BE, and EAC tissue using Students’ t-test between two groups.ResultsOur results showed decreased gene and protein expression of pro-apoptotic factors (bad, bak and bax) and increased expression of anti-apoptotic factors (bcl-2, Bcl-xL) in BE and EAC compared to normal tissues. There was increased gene and protein expression of PKC-δ, cIAP2, FLIP, NF-kB, IGF-1, Akt, and Ki67 in BE and EAC samples compared to normal esophagus. Further, an increased folds changes in mRNA expression of proapoptotic factors, antiapoptotic factors, PKC-δ, IGF-1, Akt, and Ki-67 was associated with obesity.ConclusionPatients with EAC had increased expression of cIAP2 and FLIP, and PKC-δ which is associated with inhibition of apoptosis and possible progression of esophageal adenocarcinoma.

CIAP-2 protein is upregulated by human papillomavirus in oropharyngeal cancers: role in radioresistance in vitro

BackgroundHigh-risk human papillomaviruses are the causal agents of a subset of head and neck cancers. A previous transcriptomic analysis showed that cIAP2 protein, involved in cell survival and apoptosis, is upregulated in OKF6 oral cells that express HPV16 E6/E7. In addition, cIAP2 promotes radioresistance, a very important concern in HNC treatment. However, cIAP2 increase has not yet been evaluated in oropharyngeal carcinomas (OPCs), nor has been the role of cIAP2 in HNC radioresistance.MethodsWe carried out a descriptive-analytical retrospective study in 49 OPCs from Chilean patients. We determined the expression of cIAP2 at transcript and proteins levels using reverse-transcriptase -polymerase chain reaction and immunohistochemistry, respectively. HPV and p16 expression were previously analyzed in these specimens. In addition, SCC-143 HNC cells ectopically expressing HPV16 E6/E7 were analyzed for cIAP2 expression and after transfection with a siRNA for HPV16 E6/E7 knocking down.ResultsWe found a statistically significant association between HPV presence and cIAP2 expression (p = 0.0032 and p = 0.0061, respectively). An association between p16 and cIAP2 levels was also found (p = 0.038). When SCC-143 cells were transfected with a construct expressing HPV16 E6/E7, the levels of cIAP2 were significantly increased (p = 0.0383 and p = 0.0115, respectively). Conversely, HPV16 E6 and E7 knocking down resulted in a decrease of cIAP2 levels (p = 0.0161 and p = 0.006, respectively). Finally, cIAP2 knocking down in HPV16 E6/E7 cells resulted in increased apoptosis after exposure to radiation at 4 and 8 Gy (p = 0.0187 and p = 0.0061, respectively).ConclusionThis study demonstrated for the first time a positive relationship between HPV presence and cIAP2 levels in OPCs. Additionally, cIAP2 knocking down sensitizes HNC cells to apoptosis promoted by radiation. Therefore, cIAP2 is a potential therapeutic target for radiation in HPV-driven HNC.

Abstract We060: Hypoxia Inducible Factor-2α Enhances Neutrophil Survival and Promotes Cardiac Injury Following Myocardial Infarction via cIAP-1 Signaling

Rationale: Heart failure is a major cause of mortality following myocardial infarction (MI). Neutrophils (PMNs) are among the first immune cells to accumulate in the infarcted region. While some long-term beneficial functions of PMN in heart injury are now appreciated, en mase PMN accumulation in injured hearts is still associated with worsened resolution of inflammation and disease outcomes. MI causes extensive hypoxic injury to heart tissue, where hypoxia-inducible factors (HIFs) play critical roles in cellular functions. While HIF1α regulation of cell survival, migration and metabolism have been well-studied, the role of HIF-2α in these processes is not well-understood. Even less is known of HIF-2α contributions to PMN effector functions, especially in the context of MI. Objectives: The current study aimed to 1. Mechanistically explore how HIF-2α regulates survival of tissue infiltrating PMNs post-MI and 2. Determine how HIF-2α activity in PMNs impacts heart injury resolution post-MI, and whether specific HIF-2α deletion in PMNs can alleviate MI-induced tissue injury. Methods & Results: Infarct size, cardiac functions monitored by echocardiography, and scar tissue formation after left anterior descending coronary ligation injury model were compared between littermate control and specific PMN HIF-2α depletion (Ly6G-cre +/- HIF-2α fl/fl ) mice. Myocardial infarction size, cardiac dysfunction, scare tissue deposit and survival of tissue infiltrating PMNs post-MI were substantially attenuated in mice with PMN HIF-2α deletion. A significantly reduced lifespan of HIF-2α knockout PMNs was further confirmed by fate-mapping EdU pulse chase experiments. Mechanistically, molecular studies revealed that HIF-2α transcriptionally regulates expression of the pro-survival factor cIAP1 in PMNs binding to an HRE located in the promoter region of BIRC2 , in a hypoxia-inducible manner. Ex-vivo pharmacological inhibition of cIAP1 expression in PMNs using Birinapant resulted in dramatic cell death, establishing the critical role of cIAP1 in PMN survival. Finally, our data demonstrate that the protective effect of HIF-2α deletion in PMNs on MI outcomes was due to elevated recruitment of reparative macrophages into infarcted hearts. Conclusion: HIF-2α, through cIAP1 regulation, promotes PMN survival and tissue retention post-MI, leading to worsen cardiac functions and scar formation.

Effect of Neisseria gonorrhea Infection on Gene Expression of p53 and cIAP2 Genes in Cervical Cancer

Background: Neisseria gonorrhoeae (N. gonorrhea) is one of the most common bacterial infections causing health problems in the epithelial lining of the cervix. Previous studies did not adequately address its role in cervical cancer (CEC), therefore, the current study aimed to determine the impact of N. gonorrhea infection on gene expression of p53 and cIAP2 in CEC. Materials and Methods: samples were collected from 20 women suffering from cervical cancer with N. gonorrhea infection (CC-NG), and 20 women who had cervical cancer without N. gonorrhea infection (CC) and 40 healthy women as the control group. N. gonorrhea diagnosis was done by Modified Thayer-Martin (MTM) agar and gram stain. Gene expression of p53 and cIAP2 was carried out using real-time PCR. Results: P53 and cIAP2 genes had high molecular expression (folding change) in CC-NG (17.172 and 31.135 respectively) and CC (16.02 and 15.45 respectively) compared to healthy control (1.00) (P>0.05). Moreover, when the expression of both genetic indicators was compared to each other an increase in gene transcription in the cases of CC-NG compared to CC was observed. The antibiotic resistance pattern for the tested Neisseria gonorrhoeae strains was as follows: to ceftriaxone (100%), penicillin (96%), amoxicillin (90%), tetracycline (89%) and ciprofloxacin (77%) but low to cefixime (4%), spectinomycin (5%) and azithromycin (9 2%). Conclusion: N. gonorrhea infection can be determine as risk factor for CEC development.

Abstract 3132: Examining The Role Of The Lung Endothelial Cell Anti-apoptotic Protein C-iap2 In Schistosomiasis-associated Pulmonary Hypertension

Introduction: Schistosomiasis-associated Pulmonary Hypertension (Sch-PH) is the most common form of group I PH worldwide and remains with no targeted therapy. Previously, we observed that the loss of the anti-inflammatory protein caveolin-1 (Cav-1) in lung endothelial cells (EC) contributed to the survival of the abnormal EC phenotype in Sch-PH. Abnormal cell survival has been associated with some members of the inhibitor of apoptosis protein (IAP) family, but their role in Sch-PH is unknown. Hypothesis: The major etiological agent of Sch-PH, i.e., S. mansoni , may contribute to the abnormal lung EC phenotype via altered IAP family expression, specifically the inducible member c-IAP2. Methods/Methods: To test this hypothesis, we first quantified constitutive c-IAP1 and inducible c-IAP2 expression on lung samples from male and female control and pre-clinical S. mansoni egg-exposed mice (240 eggs/gram body weight intraperitoneally followed by intravenous injection of 175 eggs/gram body weight). Then, the specific contribution of EC-c-IAP2 expression to the progression of the disease was evaluated in our new mouse model ( Cdh5.CreERT2;cIAP1 -/- ,cIAP2 fl/fl - Cdh5.CreERT2;cIAP1 +/- ,cIAP2 +/fl ). EC- Cav1 -/- mice were also evaluated to test the contribution of EC-Cav-1 to lung c-IAP2 expression. Results/Discussion: Western blot and immunohistochemistry analysis revealed a reduction in c-IAP2 expression in the whole lung tissue of S. mansoni egg-exposed mice compared to controls (1.21 ± 0.12; 0.88 ± 0.06, control and egg-exposed mice respectively; p<0.05; n=6). No difference was observed in c-IAP1 expression. Preliminary data indicate that genetic ablation of c-IAP2 in EC heterozygous mice promoted a mild increase in microvascular thickness and area in Masson’s Trichrome -stained lung sections. Consistent with our previous findings, c-IAP2 expression was also significantly impaired when Cav-1 expression was absent in lung ECs, suggesting that EC-Cav-1 may contribute to reduced lung c-IAP2 expression, leading to the severe vascular remodeling that underlies the development of Sch-PH. Conclusion: Our data is uncovering whether c-IAP2 expression is a novel and specific molecular target for future therapeutic approaches against chronic Sch-PH.

The Role of miR-29a and miR-143 on the Anti-apoptotic MCL-1/cIAP-2 Genes Expression in EGFR Mutated Non-small Cell Lung Carcinoma Patients.

The survival rate of lung cancer is low due to the high frequency of drug resistance in patients with mutations in the driver genes. Overexpression of anti-apoptotic genes is one of the most prominent features of tumor drug resistance. EGFR signaling induces the expression of anti-apoptotic genes. Also, microRNAs (miRNAs) have a critical role in regulating biological functions such as apoptosis; a process mostly eluded in cancer progression. The mutation screening was performed on one thousand non-small cell lung carcinoma patients to enroll clinical samples in this study. Bioinformatics analysis predicted that miRNAs (miR-29a, miR-143) might regulate MCL-1 and cIAP-2 expression. We investigated the expression of MCL-1, cIAP-2, miR-29a, and miR-143 encoding genes in adenocarcinoma patients with or without EGFR mutations before treatment. The potential role of miR-29a and miR-143 on gene expression was evaluated by overexpression and luciferase assays in HEK-293T cells. EGFR mutations were found in 262 patients (26.2%) with a greater incidence in females (36.23% vs. 20.37%, P = 0.001). The expression levels of MCL-1 and cIAP-2 genes in patients with mutated EGFR were higher than those of wild-type EGFR. In contrast, compared to those of patients with wild-type EGFR, the expression levels of miR-29a and miR-143 were lower in the patients carrying EGFR mutations. In cell culture, overexpression of miR-29a and miR-143 significantly downregulated the expression of MCL-1 and cIAP-2. Dual-luciferase reporter experiments confirmed that miR-29a and miR-143 target MCL-1 and cIAP-2 mRNAs, respectively. Our results suggest that upregulation of EGFR signaling in lung cancer cells may increase anti-apoptotic MCL-1 and cIAP-2 gene expression, possibly through downregulation of miR-29a-3p and miR-143-3p.

Expression and clinical significance of Capase3 and C-IAP1/2 in ectopic endometrium of patients with endometriosis.

To analyze the expression of capase3 and C-IAP1/2 in endometriosis and their relationship with clinical practice. Ectopic and eutopic endometrial tissues were collected from women with endometriosis, and the control tissues were obtained from regular patients without endometriosis. The expression level of capase3 and C-IAP1/2 was detected by immunohistochemistry; in addition, the relationship between C-IAP1/2 expression and the clinical stage of endometriosis was analyzed. The expression of Caspase-3 in ectopic and eutopic endometrium was significantly lower than that in the control group (P < 0.005). The expression of C-IAP1/2 in ectopic and situ endometrium was significantly higher than in the control group (P < 0.005). The expression of C-IAP1/2 in stage III-IV was higher than in stage I-II endometriosis. The positive expression of c-IAP1 protein in ectopic endometrial tissue was negatively correlated with the positive expression of Caspase-3 protein in ectopic endometrial tissue (P<0.001). The low expression of Caspase-3 and the high expression of C-IAP1/2 in the ectopic endometrium and eutopic endometrial tissues compared with the controls. The results indicated that the apoptotic ability of eutopic and ectopic endometrium is weakened, which is involved in the pathogenesis of endometriosis. It is expected to be a target for the diagnosis and therapy of this disease. At the same time, the expression level of C-IAP1/2 is related to the stage of endometriosis, which can guide clinical treatment.

Anastasis enhances metastasis and chemoresistance of colorectal cancer cells through upregulating cIAP2/NFκB signaling

Chemotherapy is a common strategy to treat cancer. However, acquired resistance and metastasis are the major obstacles to successful treatment. Anastasis is a process by which cells survive executioner caspase activation when facing apoptotic stress. Here we demonstrate that colorectal cancer cells can undergo anastasis after transient exposure to chemotherapeutic drugs. Using a lineage tracing system to label and isolate cells that have experienced executioner caspase activation in response to drug treatment, we show that anastasis grants colorectal cancer cells enhanced migration, metastasis, and chemoresistance. Mechanistically, treatment with chemotherapeutic drugs induces upregulated expression of cIAP2 and activation of NFκB, which are required for cells to survive executioner caspase activation. The elevated cIAP2/NFκB signaling persists in anastatic cancer cells to promote migration and chemoresistance. Our study unveils that cIAP2/NFκB-dependent anastasis promotes acquired resistance and metastasis after chemotherapy.

BV6, AN ANTAGONIST OF INHIBITOR OF APOPTOSIS PROTEINS, SENSITIZES RESISTANT MANTLE CELL LYMPHOMA CELLS TO VENETOCLAX

Introduction: Although Bruton’s tyrosine kinase inhibitors (BTKi) and CAR T-cell therapy have achieved remarkable efficacy in the treatment of mantle cell lymphoma (MCL), it remains incurable due to the inevitable development of therapeutic resistance. The BCL-2 inhibitor venetoclax is effective in many relapsed MCL patients, including those who progressed on BTKi, but subsequent relapse to venetoclax yields poor clinical outcomes. Hence, novel therapeutics and combination therapies are required to tackle the clinical challenges. Here, we investigated BV6, an antagonist of inhibitor of apoptosis proteins (IAPs), alone and in combination with venetoclax in multiple therapy-resistant MCL models. Methods: We performed single-cell RNA-seq to assess gene expression in ibrutinib-sensitive, ibrutinib-resistant, and dual ibrutinib-/CAR T-resistant MCL patients. Cell lines with acquired resistance to ibrutinib or venetoclax, as well as primary tumor cells from patients who relapsed after multiple therapies, were used as models of MCL resistance. CellTiter-Glo® luminescent assay was used to measure cell viability; annexin V/PI staining was used to measure the induction of apoptosis; and western blotting was used to assess IAP and apoptosis signaling protein expression across MCL cell lines after drug treatment. Results: The single-cell RNA-seq analysis demonstrated that IAP gene expression was not influenced by patient response to ibrutinib and CAR T-cell therapy, and western blotting showed that IAP proteins were broadly expressed across all MCL cell lines. To determine the on-target effects of BV6, we treated JeKo-1, JeKo-IBN-R, Mino, and Mino-VEN-R cells with BV6 and examined the expression of IAPs. BV6 treatment for 4h markedly reduced c-IAP1 and c-IAP2 expression, and moderately reduced XIAP expression. BV6 inhibited cell viability in both ibrutinib- and venetoclax-resistant cell lines, and BV6 treatment for 24 h dose-dependently induced apoptosis in MCL cells, including not only cell lines with acquired resistance but also patient primary cells, independent of their resistance to ibrutinib, venetoclax, and CAR T-cell therapy. We observed a striking and significant synergy in the cell viability assay when ibrutinib- or venetoclax-resistant cells were treated with BV6 combined with venetoclax (combination index < 1), and a dramatic enhancement of apoptosis (p < 0.001). The combination eradicated c-IAP1 and c-IAP2 expression, while XIAP was synergistically diminished. This was accompanied by strong caspase-3 activation and PARP cleavage. This combination therapy is currently under evaluation in venetoclax-resistant mouse model in vivo. Conclusions: Our findings indicate that a combination of IAP antagonists with apoptosis inducers can be exploited as a rational strategy to overcome therapeutic resistance in MCL. This study was supported by philanthropic funds from the Kimmel Research fund and various donor funds. Keywords: Aggressive B-cell non-Hodgkin lymphoma, Combination Therapies, Molecular Targeted Therapies No conflicts of interests pertinent to the abstract.

Divergent effect of Birinapant, and BV6 SMAC mimetic on TNFα induced NF-κB signaling and cell viability in activated hepatic stellate cells.

Tumor necrosis factor-α (TNFα) is a pleiotropic cytokine involved in nuclear factor kappa B (NF-κB) mediated cell survival as well as cell death. High serum TNFα levels correlate with liver fibrosis and enhance hepatic stellate cell (HSC) viability. However, the regulatory role of cellular inhibitor of apoptosis-1/2 (cIAP1/2) during TNFα induced NF-κB signaling in activated HSCs is largely unknown. Activated HSCs were treated with cIAP1/2 inhbitiors i.e., SMAC mimetic BV6, and Birinapant in the presence of TNFα and macrophage conditioned media. TNFα cytokine increased cIAP2 expression and enhanced cell viability through the canonical NF-κB signaling in activated HSCs. cIAP2 inhibition via BV6 decreased the TNFα induced canonical NF-κB signaling, and reduced cell viability in activated HSCs. SMAC mimetic, Birinapant alone did not affect the cell viability but treatment of TNFα sensitized HSCs with Birinapant induced cell death. While BV6 mediated cIAP2 ablation was able to decrease the TNFα induced canonical NF-κB signaling, this effect was not observed with Birinapant treatment. Secreted TNFα from M1 polarized macrophages sensitized activated HSCs to BV6 or Birinapant mediated cell death. However, M2 polarized macrophage conditioned medium rescued the activated HSCs from BV6 mediated cytotoxicity. In this study, we describe the regulatory role of cIAP2 in TNFα induced NF-κB signaling in activated HSCs. Targeting cIAP2 may be a promising approach for liver fibrosis treatment via modulating NF-κB signaling in activated HSCs.

Abstract 15005: Tlr4/py14-Caveolin-1-Mediated Endothelial C-iap2 Expression During Schistosomiasis-Associated Pulmonary Arterial Hypertension

Introduction: During schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH), hyperproliferation of abnormal endothelial cells (ECs) contributes to development of severe vascular lesions within the lungs; a life-threatening phenomenon that remains with no target therapy. Hypothesis: Here, we found that antigenic molecules from the major etiological agent of Sch-PAH, i.e., S. mansoni , amplify the secretion of the antiapoptotic protein c-IAP2 via TLR4-pY14Cav-1 signaling pathway, which we hypothesized to contribute to generation of an EC memory of survival and severity of PAH. Methods/Results: Cav-1 deficiency via shedding of extracellular vesicles (EVs) leads to survival of an apoptosis-resistant EC phenotype during idiopathic PAH. Similarly, S. mansoni egg antigens also reduced lung EC-Cav-1 expression, suggesting that Cav-1 also plays a role during pathogen-associated PAH. Cav-1 depletion via EVs precedes its phosphorylation at residue Tyr14 (pY14Cav-1), which in turn, contributes to EV loading. Among apoptotic regulators, IAPs have been found as a cargo of EVs in different conditions, including in TLR4-activated cells. Accordingly, our data indicates that S. mansoni egg antigen p40 also activated TLR4/NFkB-mediated signaling, inducing c-IAP2 expression and a time-dependent phosphorylation of Cav-1 in human lung microvascular EC (HMVEC-L: 228.2 +/- 38.28% of control; p&lt;0.05; n=4). Moreover, although Sm-p40 alone was unable to induce shedding of EVs, combination with NFkB-associated proinflammatory mediators (TNF-α, IL-6, and ATP), significantly increased EV shedding by HMVEC-L, suggesting that S. mansoni may epigenetically prime ECs, but co-factors are required to induce EV shedding. Finally, Sch-PAH model using EC- Cav1 -/- mice ( End-scl.Cre ERT2 ;Rosa mt/mg ;Cav1 fl/fl ) revealed that Cav-1 absence led to accumulation of eggs within the lungs and loss of eGFP+ cells, indicating that EC-Cav-1 phosphorylation may be required to development of Sch-PAH. Conclusions: Our data suggest that S. mansoni -induced pY14Cav-1 is associated to expression of the anti-apoptotic c-IAP2 protein, which may be critical for prolonged survival of a pathogenic EC phenotype during the development of Sch-PAH.

DIFFERENTIAL EXPRESSION AND STABILITY OF XIAP AND CIAP-1 MAY INFLUENCE THE APOPTOSIS-RESISTANT PHENOTYPE OF LUNG FIBROBLASTS IN IDIOPATHIC PULMONARY FIBROSIS

DIFFERENTIAL EXPRESSION AND STABILITY OF XIAP AND CIAP-1 MAY INFLUENCE THE APOPTOSIS-RESISTANT PHENOTYPE OF LUNG FIBROBLASTS IN IDIOPATHIC PULMONARY FIBROSIS

A019 Obesity Increases the Expression of FLIP and cIAP2 which Associates with Decreased Apoptosis and Tumor Progression in Esophageal Adenocarcinoma

A019 Obesity Increases the Expression of FLIP and cIAP2 which Associates with Decreased Apoptosis and Tumor Progression in Esophageal Adenocarcinoma

Abstract 388: Role Of The Antiapoptotic C-iap2 On The Generation Of An Endothelial Memory In Schistosomiasis-associated Pulmonary Arterial Hypertension

Introduction: Schistosomiasis-associated Pulmonary Arterial Hypertension (Sch-PAH) is a life-threatening complication of chronic S. mansoni infection, which can evolve to heart failure and death. During PAH, hyperproliferation of apoptosis-resistant endothelial cells (ECs) has been extensively reported, but therapeutic approaches to reverse this pathological phenotype remain clinically challenging. Hypothesis: Thus, our hypothesis is that antigenic molecules from S. mansoni eggs amplify the secretion of inhibitor of apoptosis protein 2 (c-IAP2), leading to generation of an abnormal EC memory of survival and the development of PAH. Methods/Results: Previously, we showed that depletion of the anti-apoptotic protein Caveolin-1 (Cav-1) via shedding of extracellular vesicles (EVs) leads to the survival of an abnormal EC phenotype through an unclear mechanism. Analysis of survival-associated genes in isolated murine lung ECs from Flk1 +/GFP ;Cav1 -/- mice, revealed high expression of the anti-apoptotic genes BIRC3 and BIRC5 (which encodes cIAP2 and survivin, respectively) when compared to control ECs. Interesting, exposure to 1 μg/mL of the major S. mansoni egg antigen Sm-p40 induced time-dependent phosphorylation of Cav-1 at residue Tyr14 in human lung microvascular EC (HMVEC-L: 228.2 +/- 38.28% of control; p&lt;0.05; n=4), culminating in c-IAP2 expression with no difference on the constitutive expression of c-IAP1. Furthermore, Sm-p40 treatment of HMVEC-L in the presence of pro-inflammatory mediators IL-6, TNF-α, and ATP induced a significant release of EVs containing c-IAP2. Finally, in vivo analysis of lungs from S. mansoni -infected mice confirmed a significant decrease in Cav-1 expression unique to the egg-dependent granuloma area, indicating that local inflammatory response due to egg-derived antigenic molecules is essential for reprogramming and survival of an abnormal EC phenotype during Sch-PAH. Conclusions: Our data suggest that S. mansoni -induced Cav-1 depletion promotes the secretion of the anti-apoptotic c-IAP2 protein, which may be critical for prolonged survival of a pathogenic EC phenotype during the development of Sch-PAH.

FL118, acting as a 'molecular glue degrader', binds to dephosphorylates and degrades the oncoprotein DDX5 (p68) to control c-Myc, survivin and mutant Kras against colorectal and pancreatic cancer with high efficacy.

ABSTRACTBackgroundPancreatic ductal adenocarcinoma (PDAC), a difficult‐to‐treat cancer, is expected to become the second‐largest cause of cancer‐related deaths by 2030, while colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer deaths. Currently, there is no effective treatment for PDAC patients. The development of novel agents to effectively treat these cancers remains an unmet clinical need. FL118, a novel anticancer small molecule, exhibits high efficacy against cancers; however, the direct biochemical target of FL118 is unknown.MethodsFL118 affinity purification, mass spectrometry, Nanosep centrifugal device and isothermal titration calorimetry were used for identifying and confirming FL118 binding to DDX5/p68 and its binding affinity. Immunoprecipitation (IP), western blots, real‐time reverse transcription PCR, gene silencing, overexpression (OE) and knockout (KO) were used for analysing gene/protein function and expression. Chromatin IP was used for analysing protein‐DNA interactions. The 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromid assay and human PDAC/CRC cell/tumour models were used for determining PDAC/CRC cell/tumour in vitro and in vivo growth.ResultsWe discovered that FL118 strongly binds to dephosphorylates and degrades the DDX5 oncoprotein via the proteasome degradation pathway without decreasing DDX5 mRNA. Silencing and OE of DDX5 indicated that DDX5 is a master regulator for controlling the expression of multiple oncogenic proteins, including survivin, Mcl‐1, XIAP, cIAP2, c‐Myc and mutant Kras. Genetic manipulation of DDX5 in PDAC cells affects tumour growth. PDAC cells with DDX5 KO are resistant to FL118 treatment. Our human tumour animal model studies further indicated that FL118 exhibits high efficacy to eliminate human PDAC and CRC tumours that have a high expression of DDX5, while FL118 exhibits less effectiveness in PDAC and CRC tumours with low DDX5 expression.ConclusionDDX5 is a bona fide FL118 direct target and can act as a biomarker for predicting PDAC and CRC tumour sensitivity to FL118. This would greatly impact FL118 precision medicine for patients with advanced PDAC or advanced CRC in the clinic. FL118 may act as a ‘molecular glue degrader’ to directly glue DDX5 and ubiquitination regulators together to degrade DDX5.

Dimethyl Fumarate Induces Apoptosis via Inhibiting NF-κB and STAT3 Signaling in Adult T-cell Leukemia/Lymphoma Cells

Adult T-cell leukemia (ATL) is a peripheral T lymphocytic malignancy caused by human T-cell leukemia virus type 1 (HTLV-1) infection. Despite treatment that includes novel agents that have been developed, most of ATL patients relapse and acquire multidrug resistance. As a result, the creation of newer agents is critical. Dimethyl fumarate (DMF) has several effects in cancer cells, including cell signaling, proliferation and cell death. However, its antitumor effects on ATL cells remain unknown. In this study, we looked at DMF's antitumor effects on ATL cells. We examined the effects of DMF on proliferation and apoptosis using the trypan blue exclusion assay and annexin V/propidium iodide staining in HTLV-1-infected and transformed T-cell lines, MT-1 and MT-2 cells. We also evaluated the effects of DMF on the nuclear factor-kappa B (NF-κB) and signal transducers and activators of transcription 3 (STAT3) signaling pathways and anti-apoptotic proteins by immunoblotting. DMF inhibited proliferation and induced apoptosis in MT-1 and MT-2 cells by activating poly ADP-ribose polymerase (PARP). Furthermore, DMF inhibited the constitutive activation of both canonical and non-canonical NF-κB pathways in MT-2 cells and the non-canonical NF-κB pathway in MT-1 cells. DMF also inhibited the constitutive tyrosine phosphorylation of STAT3 and the expression of anti-apoptotic proteins, c-IAP2 and survivin in both cells. These results indicate that DMF inhibits proliferation and induces apoptosis in HTLV-1-infected and transformed T-cells by suppressing NF-κB and STAT3 signaling pathways. DMF should be investigated further as a novel agent for ATL.

Inhibition of cIAP1 in the effective suppression of chemotherapy‑resistant hepatoblastoma.

Cellular inhibitor of apoptosis protein‑1 (cIAP1) is a key regulator of programmed cell death and is known to be associated with chemotherapeutic resistance. The present study aimed to investigate the antitumor efficacy of birinapant, a novel selective inhibitor of cIAP1, against cisplatin (CDDP)‑resistant hepatoblastoma (HB) cells. Western blot analysis was used to investigate the antitumor effect of birinapant on cIAP1 expression in Huh6 cells at the protein level. A WST‑8 assay was performed to evaluate the tumor growth inhibitory effect of birinapant on the human HB cell lines, Huh6 and HepG2. Huh6 cells were exposed to CDDP and/or birinapant in order to confirm tumor growth inhibition. The antitumor efficacy of birinapant plus CDDP combination therapy was significantly higher than that of CDDP monotherapy in a dose‑dependent manner (P=0.035). The study also investigated the antitumor efficacy of birinapant plus CDDP combination therapy in an established xenograft model of SCID mice. Compared with CDDP monotherapy, birinapant combined with CDDP showed better inhibition of tumor growth (P=0.121). It was observed that the mRNA expression of cIAP1 in tumors was significantly enriched in the CDDP monotherapy group compared with that in the untreated group. Furthermore, immunohistochemical staining was performed to compare cIAP1 expression in pre‑ and post‑chemotherapy specimens in patients with HB, and a significant increase was observed in the post‑chemotherapy specimens (P<0.001). CDDP‑resistant Huh6 (Huh6‑CDDPR) cells were also established following repeated exposure to CDDP. Birinapant was substantially more effective against the Huh6‑CDDPR cells than against the Huh6 wild‑type cells. Taken together, these findings suggest that repeated exposure to CDDP enhances cIAP1 expression in HB cells and that birinapant is a promising therapeutic drug for CDDP‑resistant HB.

Expression levels of cellular inhibitor of apoptosis proteins and colitogenic cytokines are inversely correlated with the activation of interferon regulatory factor 4.

Cellular inhibitors of apoptosis proteins 1 (cIAP1) and 2 (cIAP2) are involved in signaling pathways mediated by Toll-like receptors (TLRs) and tumor necrosis factor (TNF)-α. Excessive activation of TLRs and TNF-α underlies the immunopathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). However, the roles played by cIAP1 and cIAP2 in the development of CD and UC remain poorly understood. In this study, we attempted to clarify the molecular link between cIAP1/cIAP2 and colonic inflammation. Human monocyte-derived dendritic cells (DCs) treated with siRNAs specific for cIAP1 or cIAP2 exhibited reduced pro-inflammatory cytokine responses upon stimulation with TLR ligands. Expression of cIAP1 and cIAP2 in human DCs was suppressed in the presence of interferon regulatory factor 4 (IRF4). This effect was associated with inhibition of cIAP1 and cIAP2 polyubiquitination. To verify these in vitro findings, we created mice overexpressing IRF4 in DCs and showed that these mice were resistant to trinitrobenzene sulfonic acid-induced colitis as compared with wild-type mice; these effects were accompanied by reduced expression levels of cIAP1 and cIAP2. Pro-inflammatory cytokine production by mesenteric lymph node cells upon stimulation with TLR ligands was reduced in mice with DC-specific IRF4 overexpression as compared with that in wild-type mice. Finally, in clinical samples of the colonic mucosa from patients with CD, there was a negative relationship between the percentage of IRF4+ DCs and percentages of cIAP1+ or cIAP2+ lamina propria mononuclear cells. These data suggest that the colitogenic roles of cIAP1 and cIAP2 are negatively regulated by IRF4.

MiR-192/NKRF axis confers lung cancer cell chemoresistance to cisplatin via the NF-κB pathway.

BackgroundChemoresistance influences the therapeutic effect of cisplatin and remains a major obstacle to its clinical use. MicroRNAs are associated with drug resistance of various tumors. However, the association between microRNAs and cisplatin in lung cancer remains largely unclear.MethodsMicroRNA expression profile was identified by microRNA microarray between the lung cancer cisplatin‐sensitive cell line A549 (A549) and cisplatin‐resistant cell line A549/DDP (A549/DDP) and confirmed by quantitative real‐time‐PCR (qRT‐PCR). In vitro loss‐ and gain‐of‐function studies were performed to reveal the biological function of miR‐192 and related mechanism of the microRNA‐192/NKRF axis in lung cancer cell cisplatin resistance.ResultsIncreased miR‐192 expression was detected in A549/DDP cells compared to A549. High miR‐192 expression significantly suppressed apoptosis, enhanced proliferation, and conferred resistance to cisplatin in lung cancer cells. NF‐κB repressing factor (NKRF), which is involved in the regulation of the NF‐κB signaling pathway, was identified as a direct target of miR‐192. Overexpression of miR‐192 significantly increased the nuclear protein amount and transcriptional activation of NF‐κB and expression of cIAP1, cIAP2, Bcl‐xl and XIAP, whereas decreased miR‐192 expression did the opposite. Inhibition of the NF‐κB signal pathway by curcumin reversed the effect of upregulation of miR‐192 on proliferation, apoptosis and cisplatin‐resistance in lung cancer cells. These results indicated that miR‐192/ NKRF axis enhances the cisplatin resistance of lung cancer cells through activating the NF‐κB pathway in vitro.ConclusionsMiR‐192 plays a crucial role in cisplatin‐resistance of lung cancer cells. Thus, MiR‐192 may represent a therapeutic target for overcoming resistance to cisplatin‐based chemotherapy in lung cancer.

Targeting cIAPs attenuates CCl4-induced liver fibrosis by increasing MMP9 expression derived from neutrophils

AimsLiver fibrosis is a growing public health concern without effective medical treatment. Recent reports have indicated that inhibitors of apoptosis proteins (IAPs) were potential targets for idiopathic pulmonary fibrosis therapy. However, their roles have not been well identified in liver fibrosis. MethodsThe expression of IAPs were examined in human liver tissue and experimental mouse models. Liver fibrosis in CCl4-induced mouse models were investigated by Sirius red staining, RT-PCR, Western blotting after hepatocytes-specific cIAP2 knockout or IAPs inhibitor APG-1387 treatment. The underlying molecular mechanism of APG-1387 action was explored by apoptosis analysis, matrix metalloprotein 9 (MMP9) inhibition, neutrophils depletion, and CC Motif Chemokine Ligand 5 (CCL5) gene knockout in vitro and in vivo. FindingsOur study showed that increased expression of cIAP2 was associated with liver fibrosis severity in liver tissues. Deletion of cIAP2 from hepatocytes or degrading cIAPs by APG-1387 ameliorated liver fibrosis induced by CCl4. APG-1387 treatment exhibited increased expression of MMP9 and resulted in higher ratio of MMP9 to tissue inhibitor of metalloproteinase-1. MMP9 was mainly derived from CCL5 chemotactic neutrophils. Further, MMP9 inhibition by CTT peptide, neutrophil depletion by Ly6G antibody or CCL5 deficiency blocked the anti-fibrotic effects of APG-1387 in vivo. SignificanceThese results suggested that cIAPs, especially cIAP2, might play a novel role in the pathogenesis of liver fibrosis, and targeting cIAPs represented a promising therapeutic strategy for liver fibrosis by increasing MMP9 expression induced by CCL5 chemotactic neutrophils.