X-linked Inhibitor Of Apoptosis Protein Expression Research Articles

XIAP overexpressing inflammatory breast cancer patients have high infiltration of immunosuppressive subsets and increased TNFR1 signaling targetable with Birinapant

ObjectiveTo assess the expression pattern of X-linked inhibitor of apoptosis protein (XIAP), a cellular stress sensor, and delineate the associated changes in the tumor immune microenvironment (TiME) for prognostic value and new therapeutic targets in inflammatory breast cancer (IBC). MethodsImmunohistochemistry was conducted to assess the spatial localization of immune subsets, XIAP, and PDL1 expression in IBC and non-inflammatory breast cancer (nIBC) pretreatment tumors (n = 142). Validation and further exploration were performed by gene expression analysis of patient tumors along with signaling studies in a co-culture model. ResultsHigh XIAP in 37/81 IBC patients correlated significantly with high PD-L1, increased infiltration of FOXP3+ Tregs, CD163+ tumor-associated macrophages (TAMs), low CD8/CD163 ratio in both tumor stroma (TS) and invasive margins (IM), and higher CD8+ T cells and CD79α+ B cells in the IM. Gene set enrichment analysis identified cellular stress response- and inflammation-related genes along with tumor necrosis factor receptor 1 (TNFR1) expression in high-XIAP IBC tumors. Induction of TNFR1 and XIAP was observed when patient-derived SUM149 IBC cells were co-cultured with human macrophage-conditioned media simulating TAMs, further demonstrating that the TNF-α signaling pathway is a likely candidate governing TAM-induced XIAP overexpression in IBC cells. Finally, addition of Birinapant, a pan IAP antagonist, induced cell death in the pro-survival cytokine-enriched conditions. ConclusionUsing immunophenotyping and gene expression analysis in patient biospecimens along with in silico modeling and a preclinical model with a pan-IAP antagonist, this study revealed an interplay between increased TAMs, TNF-α signaling, and XIAP activation during (immune) stress in IBC. These data demonstrate the potential of IAP antagonists as immunomodulators for improving IBC therapeutic regimens.

Immunohistochemical Expression of XIAP in Mucoepidermoid Carcinoma

Objective: The X-linked inhibitor of apoptosis protein (XIAP) immunohistochemical expression was employed to assess the anti-apoptotic activity of mucoepidermoid carcinoma (MEC) in relation to different clinicopathological variables to understand if XIAP immunoexpression could reflect the histologic grade and the biologic activity and prognosis in MEC patients.
 Materials and Methods: A retrospective study was accomplished on 16 MEC cases. The worked MEC cases involved the three histologic grades, low, intermediate, and high. Assessement of XIAP immunoexpression was made in relation to different clinicopathological parameters. The analysis of data was done by Pearson`s Chi-square test. Pearson correlation co-efficiency test was used to test the association between the different variables. The P‐value <0.05 was considered to be statistically significant.
 Results: There were statistically significant differences in XIAP immunoexpression in relation to the following parameters; the TNM clinical stage (P=0.036), and the histologic grade (P=0.008). Conversely, the immunoexpression of XIAP was not significantly correlated with patients’ age (P=0.141), patients` gender (P= 0.471), and the anatomical site of the tumor (P=0.827) in MEC cases.
 Conclusion: The immunoexpression of XIAP correlates with histologic grading of MEC. Additionally, XIAP immunoexpression reflects the clinical and biological behavior of MEC.

TP induces hepatic intolerance to FasL-mediated hepatocyte apoptosis by inhibiting XIAP

Triptolide (TP) is extracted from the traditional Chinese medicine Tripterygium wilfordii Hook. F. (TWHF). Its severe toxic side effects, especially hepatotoxicity, have limited the clinical application of TP-related drugs. In this study, we investigated the mechanism of the hepatotoxic effects of TP from the perspective that TP inhibited the expression of the pro-survival protein X-linked inhibitor of apoptosis protein (XIAP) and enhanced FasL-mediated apoptosis of hepatocytes. TP and CD95/Fas antibody (Jo-2) were administered by gavage to C57BL/6 mice for 7 consecutive days. After co-administration of TP and Jo-2, mouse livers showed large areas of necrosis and apoptosis and significantly increased Caspase-3 activity. KEGG pathway enrichment analysis indicated that TP may cause the development of liver injury through the apoptotic signaling pathway. Proteinprotein interaction networks showed that XIAP played an essential role in this process. TP reduced the protein expression of XIAP after combination treatment with Jo-2/FasL in vivo/in vitro. TP and FasL co-stimulation significantly increased microRNA-137 (miR-137) levels in AML12 cells, while inhibition of miR-137 expression induced a rebound in XIAP protein expression. In conclusion, TP presensitizes hepatocytes and enhances the sensitivity of hepatocytes to the Fas/FasL pathway by inhibiting the protein expression of XIAP, leading to hepatocyte apoptosis.

Gastrodin facilitates recovery of neurological function of MCAO rats through upregulating miR-20a-5p/XIAP pathway via exosome.

Cerebral infarction (CI) is characterised by high morbidity, mortality, and disability rates. Recently, Chinese medicine has been widely used and has gained satisfactory results in the treatment of CI. Our previous study showed that gastrodin could facilitate the recovery of neurological function in middle cerebral artery occlusion (MCAO) rats. This study explores this mechanism. SD rats were separated into control, sham, model, and gastrodin groups. After MCAO surgery, the gastrodin group was administered gastrodin (100 mg/kg), and after 1/3/7 days, the ischaemic hemisphere and serum was collected, and then we extracted the circulating exosomes from the serum. We then tested the levels of XIAP (x-linked inhibitor of apoptosis protein), IAP binding proteins (SMAC, HtrA2, ARTs), and miR-20a-5p (a gastrodin potential effect target) in the brain tissues, circulating exosomes, and serum using various methods. Our results showed that circulating exosomes can penetrate the blood-brain barrier (BBB) and that gastrodin can upregulate the amount of miR-20a-5p in circulating exosomes. The circulating exosomes penetrate the BBB and upregulate the expression of XIAP in the ischaemic hemisphere. Gastrodin can also decrease the amount of IAP binding proteins (SMAC, HtrA2, ARTs). Gastrodin can increase the amount of miR-20a-5p in circulating exosomes, which penetrates the BBB and upregulates XIAP expression in the ischaemic hemisphere. By inhibiting apoptosis of neurones, it can facilitate the recovery of neurological function in MCAO rats.

Nicotine promotes renal interstitial fibrosis via upregulation of XIAP in an alpha7-nAChR-dependent manner

Renal fibrosis, characterized by excessive accumulation of the extracellular matrix in the renal tubulointerstitium, can lead to chronic kidney disease (CKD), resulting in a heavy burden on families and society. Clinical studies have shown that smoking is closely associated with CKD deterioration in patients with diabetes, hypertension, polycystic kidney disease, and kidney transplantation. However, the mechanism of action of nicotine in renal fibrosis pathogenesis remains largely unknown. X-linked inhibitor of apoptosis (XIAP), a member of the inhibitor of apoptosis protein (IAP) family, is involved in apoptosis, necroptosis, autophagy, and immune response. Here, the upregulated expression of XIAP and α7 nicotine acetylcholine receptor (α7-nAChR) was determined in the kidneys of the CKD smoking group in human and animal studies. A significant positive correlation between XIAP and cotinine was observed. In addition, the nuclear translocation and transcriptional activity of SP1 were promoted when nicotine bound to α7-nAChR, resulting in XIAP overexpression and renal interstitial fibrosis progression. This phenotype can be reversed by the nicotine receptor subtype α7-nAChR antagonists methyllycaconitine. Our results revealed the complex underlying mechanism of nicotine in promoting renal fibrosis by altering SP1 nucleocytoplasmic translocation and regulating XIAP expression. These results provide novel insights into the pathogenesis and treatment of CKD.

Ceramide Analog 5cc Overcomes TRAIL Resistance by Enhancing JNK Activation and Repressing XIAP Expression in Metastatic Colon Cancer Cells

Introduction: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered to be an effective apoptosis inducer due to its selectivity for tumor cells. However, many cancer cells, especially metastatic cancer cells, often exhibit resistance to TRAIL because their apoptotic pathway is impaired or their pro-survival pathway is overactivated. TRAIL resistance is the main obstacle to current TRAIL therapy. Nowadays, ceramide analogs represent a new class of potential anticancer agents. Therefore, we hypothesized that disrupting pro-survival signaling with ceramide analogs would increase TRAIL-mediated apoptosis. Methods: MTT assay and flow cytometry were conducted to evaluate the synergistic effect of ceramide analog 5cc on TRAIL in metastatic colon cancer cells. Western blot was used to detect signaling proteins affected by 5cc. RNA interference was performed to analyze the effects of specific gene on 5cc-enhanced apoptosis. Results: Ceramide analog 5cc markedly enhanced TRAIL-induced apoptosis evidenced by increased propidium iodide/annexin V double-positive cells and PARP cleavage in SW620 and LS411N cells. At the molecular level, 5cc significantly reduced the expression of anti-apoptotic protein X-linked inhibitor of apoptosis protein (XIAP) through the activation of the c-Jun n-terminal kinase (JNK) pathway which is critically involved in sensitizing tumor cells to TRAIL/5cc combination. JNK-silenced cells exhibited a significant reversal of TRAIL/5cc-mediated apoptosis. Conclusion: Our data demonstrated that ceramide analog 5cc overcomes TRAIL resistance by enhancing JNK activation and repressing XIAP expression in metastatic colon cancer cells.

X-linked inhibitor of apoptosis protein (XIAP) expression level analyzed by immunohistochemistry (IHC) as it relates to clinical and pathologic characteristics in prostate cancer.

e17012 Background: XIAP acts in both the extrinsic and intrinsic apoptotic pathways as an inhibitor of cell death, protecting cells from a range of triggers. Regulation due to apoptosis resistance may represent a targetable factor for therapeutic intervention in prostate cancer. This study focuses on XIAP as a biomarker and its expression in correlation with disease aggression. Methods: Expression levels of XIAP was analyzed by immunohistochemistry (IHC), graded 1 through 3 according to signal intensity, in radical prostatectomy samples from 90 patients with prostate cancer with a range of phenotypes including: indolent (A), locally advanced (B), progressive to metastatic (C) and de novo metastatic (D). Prognostic data was collected and Fisher’s exact statistical analysis was performed. Secondary analyses included a Fisher’s exact test with a pairwise comparison between individual disease grades and Gleason scores. Results: Higher XIAP protein expression levels on IHC correlated with disease grade and with total Gleason score (p = 0.0008 and p = 0.0002 respectively) by Fisher’s exact test analysis, indicating more aggressive disease phenotypes. Secondary results looked at a pairwise Fisher’s exact analysis comparing XIAP expression levels among disease grades (A-D) and Gleason scores. XIAP expression only significantly differed between those with grade A and D as well as between individuals with grades B and D (measured by Bonferroni-adjusted p-value of 0.003 and 0.018 respectively). Statistical significance was also achieved in XIAP expression levels when comparing among Gleason scores 6 and 8 (p = 0.025), 6 and 9 (p = 0.0125), as well as 7 and 9 (p = 0.030). Conclusions: This study demonstrates a correlation between XIAP expression levels by IHC and aggressiveness of disease, demonstrating clinical significance of XIAP as a prostate cancer biomarker. [Table: see text]

Lead exposure disturbs ATP7B-mediated copper export from brain barrier cells by inhibiting XIAP-regulated COMMD1 protein degradation

The brain barrier is an important structure for metal ion homeostasis. According to studies, lead (Pb) exposure disrupts the transportation of copper (Cu) through the brain barrier, which may cause impairment of the nervous system; however, the specific mechanism is unknown. The previous studies suggested the X-linked inhibitor of apoptosis (XIAP) is a sensor for cellular Cu level which mediate the degradation of the MURR1 domain-containing 1 (COMMD1) protein. XIAP/COMMD1 axis was thought to be an important regulator in Cu metabolism maintenance. In this study, the role of XIAP-regulated COMMD1 protein degradation in Pb-induced Cu disorders in brain barrier cells was investigated. Pb exposure significantly increased Cu levels in both cell types, according to atomic absorption technology testing. Western blotting and reverse transcription PCR (RT-PCR) showed that COMMD1 protein levels were significantly increased, whereas XIAP, ATP7A, and ATP7B protein levels were significantly decreased. However, there were no significant effects at the messenger RNA (mRNA) level (XIAP, ATP7A, and ATP7B). Pb-induced Cu accumulation and ATP7B expression were reduced when COMMD1 was knocked down by transient small interfering RNA (siRNA) transfection. In addition, transient plasmid transfection of XIAP before Pb exposure reduced Pb-induced Cu accumulation, increased COMMD1 protein levels, and decreased ATP7B levels. In conclusion, Pb exposure can reduce XIAP protein expression, increase COMMD1 protein levels, and specifically decrease ATP7B protein levels, resulting in Cu accumulation in brain barrier cells.

Abstract GS5-08: Soluble E-cadherin: a novel prognostic biomarker and driver of brain metastasis in inflammatory breast cancer

Abstract Background: Inflammatory breast cancer (IBC) is a highly aggressive form of breast cancer with rapid onset and a strong propensity to spread to distant organs. Five-year overall survival (OS) rates remain poor, in part because of the high risk of brain metastasis: 19% of patients with IBC have brain metastases within the first 2 years after diagnosis. Our hypothesis for this study was that soluble E-cadherin (sEcad), an 80-kDa extracellular proteolytic fragment of full-length E-cadherin - a tumor promoter in IBC, is crucial for driving brain metastasis in IBC. Methods: We analyzed serum sEcad levels in from 348 IBC patients by ELISA. Four IBC cell lines [ER–/HER2+ (MDA-IBC3; SUM190) and ER–/HER2– (SUM149; BCX010)], human brain microvascular endothelial cells, and immortalized human astrocytes were used in this study. Stable overexpression of sEcad in IBC cell lines was achieved using lentiviral vectors. Mass spectrometry and Bio-ID-based proteomics assays, and RNA sequencing were used to identify sEcad-interacting proteins and potential mechanisms. In vivo, we studied tumor growth and brain metastasis in mice by injecting IBC cells into the mammary fatpad or tail vein, respectively, of SCID/Beige mice. Results: In IBC patients, higher serum sEcad levels correlated with poorer OS (p=0.02), earlier development of metastasis (p=0.006), and development of brain metastasis (p=0.04). On multivariable analysis, sEcad independently predicted OS (hazard ratio [HR]=2.07 [95% CI 1.19-3.60], p=0.01). In vitro, sEcad overexpression in IBC cell lines promoted anchorage-independent growth, migration, invasion, and resistance to anoikis. In vivo, sEcad-overexpressing SUM149 cells promoted primary tumor growth (p=0.007). Mice injected with sEcad-overexpressing MDA-IBC3 cells also had higher incidence of brain metastasis (100% vs 50%, p=0.03), metastatic burden (p=0.02) and number of metastases per mouse (p=0.0009), and had worse OS (p=0.0016), and brain metastasis-free survival (p=0.04), relative to controls. We further found that sEcad increased cancer cell adhesion to brain endothelial cells (p=0.01) and promoted induction of reactive astrocytes (as identified by high glial fibrillary acidic protein levels) in vitro and in vivo. Mechanistically, mass spectrometry and Bio-ID assays identified X-linked inhibitor of apoptosis protein (XIAP), a potent inhibitor of apoptotic cell death, as a novel binding partner of sEcad, which was validated through co-immunoprecipitation. Further analysis showed that sEcad bound to the BIR2 domain of XIAP. XIAP is the most potent and best-defined anti-apoptotic IAP family member, and it could induce NF-κB activation to inhibit tumor cell apoptosis Gene set enrichment analysis of RNA-seq profiling data showed activation of NF-kB signaling and downregulation of apoptotic pathways in the sEcad-overexpressing SUM149 cells compared with controls. Immunoblotting revealed that sEcad enhanced XIAP expression, activated NF-κB signaling, and inhibited cleavage of caspase-3 in IBC cells. Conclusions: We found that higher serum sEcad correlates with development of brain metastases and independently predicts poor OS in patients with IBC. We further found that sEcad promotes tumor growth and brain metastasis, perhaps via activation of XIAP/NF-κB signaling in breast cancer cells and promotion of endothelial cell adhesion and reactive astrocytosis in the brain microenvironment. These findings uncover a novel and crucial role for sEcad in brain metastasis and provide new insights and potential therapeutic targets for patients with metastatic IBC. Citation Format: Xiaoding Hu, Yun Xiong, Emilly S. Villodre, Juhee Song, Ganiraju C Manyam, Moises J Tacam, Jing Wang, Chandra Bartholomeusz, Debu Tripathy, Naoto T. Ueno, Wendy Woodward, Savitri Krishnamurthy, Junjie Chen, Bisrat Debeb. Soluble E-cadherin: a novel prognostic biomarker and driver of brain metastasis in inflammatory breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-08.

Overexpression of the X-Linked Inhibitor of Apoptosis Protein (XIAP) in Neurons Improves Cell Survival and the Functional Outcome after Traumatic Spinal Cord Injury.

Mechanical trauma to the spinal cord causes extensive neuronal death, contributing to the loss of sensory-motor and autonomic functions below the injury location. Apoptosis affects neurons after spinal cord injury (SCI) and is associated with increased caspase activity. Cleavage of X-linked inhibitor of apoptosis protein (XIAP) after SCI may contribute to this rise in caspase activity. Accordingly, we have shown that the elevation of XIAP resulted in increased neuronal survival after SCI and improved functional recovery. Therefore, we hypothesise that neuronal overexpression of XIAP can be neuroprotective after SCI with improved functional recovery. In line with this, studies of a transgenic mice with overexpression of XIAP in neurons revealed that higher levels of XIAP after spinal cord trauma favours neuronal survival, tissue preservation, and motor recovery after the spinal cord trauma. Using human SH-SY5Y cells overexpressing XIAP, we further showed that XIAP reduced caspase activity and apoptotic cell death after pro-apoptotic stimuli. In conclusion, this study shows that the levels of XIAP expression are an important factor for the outcome of spinal cord trauma and identifies XIAP as an important therapeutic target for alleviating the deleterious effects of SCI.

Construction and validation of a novel tumor necrosis factor-related apoptosis-inducing ligand mutant MuR5S4-TR.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively kill tumor cells but has no significant effect on normal cells. However, the use of TRAIL is limited for resistance by more than 50% of the tumor cell lines. It's very important to develop a more efficient form of TRAIL for cancer treatment. The N-terminal in soluble fragments (114-281aa) of TRAIL was redesigned to construct a novel TRAIL mutant-MuR5S4-TR. The Cell Counting Kit-8 method to explore the antitumor effects. The potential mechanisms were also explored. Novel TRAIL mutant with cell-penetrating peptides (CPP) like and Second mitochondria-derived activator of caspases (Smac) like structure-MuR5S4-TR was successfully constructed. The prokaryotic expression system was successfully built, and the MuR5S4-TR was purified and reconfirmed by western blot. MuR5S4-TR could enhance the antitumor effects of TRAIL in most of the cancer cell lines significantly, NCI-H460 lung cancer cell line, for instance. After MuR5S4-TR treatment, the expressions of death receptor 4 (DR4), DR5, Caspase-8, and cleaved Caspase-3 were remarkably increased, however, there was no significant difference in X-linked inhibitor of apoptosis expression. We constructed a novel TRAIL mutant with CPP-like and Smac-like structure-MuR5S4-TR. The MuR5S4-TR showed significantly stronger antitumor effects than TRAIL in many tumor cell lines. The MuR5S4-TR showed strong antitumor effects both in vitro and in vivo. This preliminary study implies that MuR5S4-TR may be a more efficient form of TRAIL for cancer therapy.

Caspase-3, Caspase-8 and XIAP Gene Expression in the Placenta: Exploring the Causes of Spontaneous Preterm Labour.

A better understanding of the pathogenesis of preterm birth (PTB) will allow us to lower the PTB rate, reducing perinatal morbidity and mortality. This article presents the hypothesis that premature placenta apoptosis could be a potential cause of PTB. We evaluated gene expression involved in apoptosis: caspase-3, caspase-8, and XIAP (X-linked inhibitor of apoptosis) in the placenta during pregnancy (n = 41), at the onset of preterm labour (n = 42), after preterm (n = 44) and term (n = 32) labour. We used RNA extraction, reverse transcription, and PCR. During pregnancy the gene expression of caspase-3 and caspase-8 is low, but XIAP is higher than the caspases. At the onset of preterm labour, we observed a significantly increased expression of both caspase-8 (10.7-fold, p < 0.01) and caspase-3 (2.5-fold, p < 0.01) and XIAP (3-fold; p < 0.05) compared with expression during pregnancy. Our study showed that during pregnancy, the expression of caspase genes in the placenta is low and probably controlled by high XIAP expression. At the onset of preterm labour, the expression of caspase genes increases sharply. This may initiate the onset of preterm labour.

X-linked inhibitor of apoptosis protein (XIAP) predicts disease-free survival in BRAFV600E mutant papillary thyroid carcinoma in middle eastern patients.

X-linked inhibitor of apoptosis (XIAP) is the most potent caspase inhibitory IAP family member and its over-expression is implicated in aggressive behavior of various solid tumors, including papillary thyroid carcinoma (PTC). BRAFV600E mutation is the most common oncogenic event in PTC and is also known to be associated with aggressive clinico-pathological characteristics. In this study, we investigated the prevalence of XIAP expression in more than 1600 PTCs from Middle Eastern ethnicity and its prognostic value to predict disease-free survival (DFS), in combination with the BRAFV600E mutation. Clinical data, XIAP expression by immunohistochemistry and BRAF mutation status were analyzed in 1640 Saudi PTC patients seen at our institute between 1988 - 2020. BRAFV600E mutation was found in 910 of 1640 patients (55.5%) and was significantly correlated with older age, extrathyroidal extension, bilaterality, multifocality and lymph node metastasis, but was not an independent predictor of DFS. XIAP was over-expressed in 758 of 1640 (46.2%) and was associated with aggressive clinico-pathological features. It was also found to be an independent prognostic marker for DFS (HR = 1.28, 95% CI = 1.02 - 1.60, P = 0.0342). XIAP overexpression was correlated with presence of BRAFV600E mutation in PTC patients. Interestingly, we found the ability to predict shorter DFS was 2.7-fold higher in PTCs with over-expression of XIAP and BRAFV600E mutation compared to patients with high XIAP and wild-type BRAFV600E status (HR = 2.74, 95% CI = 2.19 - 3.44, p < 0.0001). XIAP expression is an independent predictor of prognosis in Middle Eastern PTC patients. Combination of XIAP expression and BRAFV600E mutation can synergistically improve the DFS prediction in PTC patients, which may help clinicians to establish the most appropriate initial care and long-term surveillance strategies.

Effect of Butylphthalide Capsules on Smac and XIAP Expression in Rats after Ischemia Reperfusion

IntroductionLittle is known about the protective effects of butylphthalide on cerebral ischemia-reperfusion injury. This study aims to investigate the impact on the second mitochondrial-derived activator of Caspases (Smac) and X-linked inhibitor of apoptosis protein (XIAP) expression in the ischemic semidark area using a rat model of carotid artery stenosis. MethodsThirty Sprague–Dawley rats were randomly divided into the sham-operated group, carotid stenosis model controls, low-dose (20 mg/kg), medium-dose (40 mg/kg), and high-dose (80 mg/kg) butylphthalide groups. The neurological function was scored by the balance beam test (BBT). The morphological changes of brain tissue were detected by Hematoxylin-eosin (HE) staining, with apoptosis detected by Terminal Deoxynucleotidyl Transferase mediated dUTP Nick-End Labeling (TUNEL) staining. Smac and XIAP protein expression were detected by immunohistochemistry (IHC). The expressions of Smac and XIAP mRNA were detected by real-time quantitative polymerase chain reaction (RT-qPCR). ResultsHE showed that neuronal loss, nuclear consolidation, and vacuolar degeneration were significantly reduced in the medium and high-dose butylphthalide groups compared with the model controls. The BBT scores and apoptotic index were significantly lower in the medium and high doses of butylphthalide compared with the model controls. RT-qPCR and IHC showed that Smac, XIAP mRNA and protein expressions in the ischemic hemispheric region were significantly reduced in low, medium, and high doses of butylphthalide compared with the model controls (P < 0.05), showing some concentration effect. ConclusionsButylphthalide can significantly reduce Smac and XIAP mRNA and protein expression, inhibit neuronal apoptosis induced by ischemia-reperfusion injury in rats with carotid stenosis, and exert neuroprotective effects.

X-linked inhibitor of apoptosis protein is a prognostic marker for a favorable outcome in three identified subsets in resectable adenocarcinoma of the pancreas

PurposePancreatic ductal adenocarcinoma (PDAC) is currently one of the leading causes of cancer death worldwide. Therefore, building further subgroups as well as enabling individual patient therapy and diagnostics are needed. X-linked inhibitor of apoptosis protein (XIAP) is known to modulate apoptotic and inflammatory pathways. Its expression was found to correlate with patients’ survival in other tumor entities. This study aims to examine the role of XIAP in patients with PDAC in relation to the inflammatory microenvironment.MethodsThe PANCALYZE multicenter study group included 257 patients with PDAC. Paraffin-embedded tumor samples were stained immunohistochemically for CD3, CD20, CD38, CD56, CD66b, CD117, and CD163 and XIAP. These stainings were further analyzed digitally with QuPath and survival analyses were done.ResultsXIAP-positive patients with T-cell, respectively, neutrophil enriched tumors survived significantly longer compared to XIAP-negative patients (CD3: 37.6 vs. 24.6 months, p = 0.028; CD66b: 34.1 vs. 14.9 months, p = 0.027). Additionally, XIAP-positive patients showed better survival in the lymph node-negative population (48.4 vs. 24.2 months, p = 0.019). Regarding the total population, our findings did not show a correlation between XIAP expression and survival. In multivariate cox regression analyzes XIAP proves to be an independent factor for better survival in the identified subgroups (CD3: p = 0.043; CD66b: p = 0.012, N0: p = 0.040).ConclusionWe found XIAP-positive subgroups with significantly better survival in patients with PDAC in T-cell-rich, neutrophil-rich, or lymph node-negative cohorts. This could lead to further individualized cancer treatment with less aggressive therapy protocols for XIAP-positive tumors or more intensive follow-up for XIAP-negative tumors.

262 (PB-086) Poster - Spatial Immunophenotyping Identifies Differential Infiltration of Immunosuppressive Subsets in Tumor Stroma and Invasive Margin and PDL1 expression in Inflammatory and non-Inflammatory Breast Cancer Patients overexpressing X-Linked Inhibitor of Apoptosis Protein

Background: Inflammatory Breast Cancer (IBC) is a rare, but highly aggressive variant responsible for 10% of breast cancer related mortality. X-linked inhibitor of apoptosis protein (XIAP) can suppress immune-mediated tumor cell death by its ability to inhibit caspase activity, granzyme release, and activate NFkB and MAPK inflammatory crosstalk signaling. In this study we wanted to assess the pattern of expression of XIAP and to delineate the associated changes in the tumor immune microenvironment (TiME) for prognostic value in invasive breast cancers including inflammatory breast cancer (IBC).

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

MiR-515-5p suppresses trophoblast cell invasion and proliferation through XIAP regulation in preeclampsia

MicroRNAs (miRNAs) are non-coding small RNA molecules that can be secreted into the circulation and which exist in remarkably stable forms. Circulating miRNAs regulate numerous biological process and are aberrantly expressed in pathological conditions. Differentially expressed circulating miRNAs have received attention as potential biomarkers for many diseases. In this study, we revealed that miR-515-5p was significantly upregulated in maternal serum from preeclampsia patients in comparison to normal pregnant women. Bioinformatics prediction and a dual-luciferase reporter gene assay revealed that miR-515-5p directly targets the X-linked inhibitor of apoptosis protein (XIAP) 3′-untranslated region. In addition, the overexpression of miR-515-5p inhibited the proliferation and invasion of HTR-8/SVneo trophoblast cells. The decreased XIAP expression and reduced epithelial-mesenchymal transition (EMT) were observed in the preeclamptic placenta. Collectively, miR-515-5p may play critical roles in the pathogenesis of preeclampsia through suppression of XIAP, and serum miR-515-5p may act as a potential biomarker for preeclampsia.

Exosome delivery of tumor suppressive microRNA-7 to cervical cancer cells: A novel approach for regulating cervical cancer cell growth (230)

<b>Objectives:</b> Exosomes are highly stable nanosized extracellular vehicles released from cells for cell-cell communication that protect their cargo from degradation in an array of environments. Adipocytederived stem cell exosomes (ACS-exos) have unique properties that allow them to be engineered as delivery vehicles in various biological settings. The ability to manipulate the exosomes and their contents allows exosomes to be a focus of cancer therapeutics. MicroRNAs (miRNAs) are small non-coding RNAs that control gene translation and expression. Abnormal expression of tissue miRNAs has been associated with significant alterations in cell growth. MicroRNA-7 (miR-7) has an inhibitory effect on X-Linked Inhibitor of Apoptosis Protein (XIAP), which is over-expressed in cervical cancer cells, inhibiting apoptosis and promoting cell proliferation. miR-7 down-regulates XIAP in cervical carcinoma cells, increasing apoptosis and suppressing colony formation. Our objective was to develop a new therapeutic approach for cervical cancer by employing ACS-exos to deliver miR-7 to cervical cancer cells so as to elicit regulatory effects on XIAP. <b>Methods:</b> The cervical cancer cell line C-33 A was used to demonstrate the effect of miR-7 on XIAP expression. An miRNA mimic hsa-miR-7 was used for transfection. The presence of XIAP in C-33 A cells was established using Western blot, and then the cells were transfected with miR-7 using Lipofectamine ^TM RNAiMAX. The transfected cells were collected 24 and 48 hours after treatment, and the expression of XIAP was tested using Western blot. To collect exosomes, adipocyte-derived stem cells (ACS) were cultured in a growth medium with exosome-depleted FBS for 72 hours, followed by differential centrifugation. The isolated exosomes were then transfected with either miR-7 or Texas-Red fluorescent-labeled siRNA (TX-Red) using Exo-Fect^TM Exosome Transfection Reagent. Transfected exosomes were added to the C-33 A cell culture media. The cells were analyzed under a fluorescence microscope after 24 and 48 hours of growth. Western blot was used to study the expression of XIAP. The presence of Beta-Tubulin was also tested as a loading control. <b>Results:</b> The presence of XIAP in C-33 A cells was confirmed by Western blot. In the cells transfected with miR-7, Western blot demonstrated downregulation of XIAP after both 24 and 48 hours. Successful nucleotide transfection of ACS-exos and oligonucleotide integration into the C-33 A cells was confirmed by fluorescence microscopy, which demonstrated the intracellular presence of TX-Red in only the positive control C-33 A cell line. A similar downregulation of XIAP in the cells treated with miR-7 transfected ACS-exos was seen as in the miR-7 transfected cells by Western blot. Beta-Tubulin expression was seen across the control and treatment cells. <b>Conclusions:</b> Delivery of tumor-suppressive miR-7 via ACS-exos elicited downregulation of XIAP. The isolation and successful transfection of exosomes demonstrated are key processes in utilizing exosomes for cancer therapeutics. Further, the exosome cargo nucleotides integrated into the target cells and resulted in alteration of protein expression. Additional studies examining the effects of exosome-delivered miR-7 on cervical cancer cell viability, proliferation, invasion are underway. These findings highlight the promising therapeutic potential of exosomes in cervical cancer.

LncRNA WT1-AS attenuates hypoxia/ischemia-induced neuronal injury during cerebral ischemic stroke via miR-186-5p/XIAP axis

This study aimed to investigate the role and mechanism of long non-coding RNA (lncRNA) WT1 antisense RNA (WT1-AS) in cerebral ischemic stroke. The Starbase database and dual-luciferase reporter gene assay were used to analyze the interaction between lncRNA WT1 antisense RNA (lncRNA WT1-AS) and microRNA-186-5p (miR-186-5p). Reverse transcription-quantitative PCR analysis was performed to determine lncRNA WT1-AS and miR-186-5p levels. An oxygen glucose deprivation (OGD)-induced SH-SY5Y cell injury model was established. Cell viability and apoptosis were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and flow cytometric assays, respectively. Caspase 3 activity was evaluated using a caspase 3 activity detection kit. The results showed that miR-186-5p is a direct target of the lncRNA WT1-AS. In addition, lncRNA WT1-AS levels were downregulated and miR-186-5p levels were upregulated in the blood samples of patients with ischemic stroke and OGD-induced SH-SY5Y cells. WT1-AS overexpression promoted OGD-induced cell viability and reduced the cell apoptosis and caspase 3 activity. However, these effects were reversed by miR-186-5p overexpression. Furthermore, the results demonstrated that the X-linked inhibitor of apoptosis (XIAP) was directly targeted by miR-186-5p. Similarly, transfection with the miR-186-5p inhibitor reduced OGD-induced neuronal damage by upregulating XIAP expression. In conclusion, lncRNA WT1-AS attenuates hypoxia/ischemia-induced neuronal injury in cerebral ischemic stroke through the miR-186-5p/XIAP axis.