Targeting inhibitor of apoptosis proteins (IAPs) enhances susceptibility of oral squamous carcinoma cells to cisplatin.

PURPOSE: Oral Squamous Cell Carcinoma (OSCC) is the 6th most common cancer worldwide. It is generally aggressive and closely associated with chemoresistance and poor survival. There is accumulating evidence for the involvement of inhibitors of apoptosis proteins (IAPs), including IAP1 and XIAP, in mediating chemotherapy resistance in OSCC. Various strategies for targeting IAPs have been designed and tested in recent years and several small molecule IAP inhibitors are in clinical trials as monotherapies as well as in combination with radiotherapy and chemotherapy. The purpose of this study was to evaluate and compare the efficacy and biological activity of three IAP inhibitors both as stand-alone and sensitising agents to cisplatin in a preclinical model of squamous cell carcinoma of the tongue. METHODS: Cisplatin-sensitive SCC4 and -resistant SCC4cisR cells were utilised in this study. Apoptosis was evaluated by flow cytometric analysis of Annexin V/Propidium Iodide-stained cells. Expression of IAP proteins was determined by western blotting and knockdown of cIAP1, livin and XIAP was conducted by transfection of cells with siRNA. RESULTS: We establish for the first time the therapeutic efficacy of the Smac mimetic, BV6 and the XIAP inhibitor Embelin, for OSCC. Both of these IAP targeting agents synergistically enhanced cisplatin-mediated apoptotic cell death in resistant cells which was mediated in part by depletion of XIAP. In addition, knockdown of XIAP using siRNA enhanced cisplatin-mediated cell death, demonstrating the importance of targeting XIAP in this sensitisation. CONCLUSION: These findings provide pre-clinical evidence that IAP inhibition may be a valuable therapeutic option in OSCC.

Prognostic value and therapeutic potential of IAP family in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) ranks as the eighth most prevalent malignancy globally and has the eighth greatest fatality rate when compared to all other forms of cancer. The inhibitor of apoptosis protein (IAP) family comprises a collection of apoptosis-negative modulators characterized by at least one single baculovirus IAP repeat (BIR) domain in its N-terminal region. While the involvement of the IAP family is associated with the initiation and progression of numerous tumours, its specific role in HNSCC remains poorly understood. Thus, this study aimed to comprehensively examine changes in gene expression, immunomodulatory effects, prognosis, and functional enrichment of HNSCC utilising bioinformatics analysis. Elevated levels of distinct IAP family members were observed to varying degrees in HNSCC, with high BIRC2 expression indicating a worse prognosis. Additionally, Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to probe the enrichment of gene expression and biological processes related to the IAP family in HNSCC. The infiltration levels of immune cells were shown to be strongly associated with the IAP gene expression, as determined by subsequent analysis. Hence, BIRC2 could be an effective immunotherapy target for HNSCC. Collectively, novel knowledge of the biological roles and prognostic implications of IAP family members in HNSCC is presented in this study.

Overview of role of survivin in cancer: expression, regulation, functions, and its potential as a therapeutic target.

Survivin holds significant importance as a member of the inhibitor of apoptosis protein (IAP) family due to its predominant expression in tumours rather than normal terminally differentiated adult tissues. The high expression level of survivin in tumours is closely linked to chemotherapy resistance, heightened tumour recurrence, and increased tumour aggressiveness and serves as a negative prognostic factor for cancer patients. Consequently, survivin has emerged as a promising therapeutic target for cancer treatment. In this review, we delve into the various biological characteristics of survivin in cancers and its pivotal role in maintaining immune system homeostasis. Additionally, we explore different therapeutic strategies aimed at targeting survivin.

Molecular mechanisms underlying the BIRC6-mediated regulation of apoptosis and autophagy.

Procaspase 9 is the initiator caspase for apoptosis, but how its levels and activities are maintained remains unclear. The gigantic Inhibitor-of-Apoptosis Protein BIRC6/BRUCE/Apollon inhibits both apoptosis and autophagy by promoting ubiquitylation of proapoptotic factors and the key autophagic protein LC3, respectively. Here we show that BIRC6 forms an anti-parallel U-shaped dimer with multiple previously unannotated domains, including a ubiquitin-like domain, and the proapoptotic factor Smac/DIABLO binds BIRC6 in the central cavity. Notably, Smac outcompetes the effector caspase 3 and the pro-apoptotic protease HtrA2, but not procaspase 9, for binding BIRC6 in cells. BIRC6 also binds LC3 through its LC3-interacting region, probably following dimer disruption of this BIRC6 region. Mutation at LC3 ubiquitylation site promotes autophagy and autophagic degradation of BIRC6. Moreover, induction of autophagy promotes autophagic degradation of BIRC6 and caspase 9, but not of other effector caspases. These results are important to understand how the balance between apoptosis and autophagy is regulated under pathophysiological conditions.

Synergistic cytotoxicity of decitabine and YM155 in leukemia cells through upregulation of SLC35F2 and suppression of MCL1 and survivin expression.

The hypomethylation agent decitabine (DAC), in combination with other apoptosis inducers, is considered a potential modality for cancer treatment. We investigated the mechanism underlying the combined cytotoxicity of DAC and YM155 in acute myeloid leukemia (AML) cells because of increasing evidence that YM155 induces apoptosis in cancer cells. Co-administration of DAC and YM155 resulted in synergistic cytotoxicity in AML U937 cells, which was characterized by the induction of apoptosis, NOXA-dependent degradation of MCL1 and survivin, and depolarization of mitochondria. Restoration of MCL1 or survivin expression attenuated DAC/YM155-induced U937 cell death. DAC initiated AKT and p38 MAPK phosphorylation in a Ca2+/ROS-dependent manner, thereby promoting autophagy-mediated degradation of ß-TrCP mRNA, leading to increased Sp1 expression. DAC-induced Sp1 expression associated with Ten-eleven-translocation (TET) dioxygenases and p300 was used to upregulate the expression of SLC35F2. Simultaneously, the activation of p38 MAPK induced by DAC, promoted CREB-mediated NOXA expression, resulting in survivin and MCL1 degradation. The synergistic cytotoxicity of DAC and YM155 in U937 cells was dependent on elevated SLC35F2 expression. Additionally, YM155 facilitated DAC-induced degradation of MCL1 and survivin. A similar mechanism explained DAC/YM155-mediated cytotoxicity in AML HL-60 cells. Our data demonstrated that the synergistic cytotoxicity of DAC and YM155 in AML cell lines U937 and HL-60 is dependent on AKT- and p38 MAPK-mediated upregulation of SLC35F2 and p38 MAPK-mediated degradation of survivin and MCL1. This indicates that a treatment regimen that amalgamates YM155 and DAC may be beneficial for AML.

Downregulation of BIRC2 hinders the progression of rheumatoid arthritis through regulating TRADD.

AIM: Rheumatoid arthritis (RA) is a chronic inflammation mediated by an autoimmune response. Baculoviral IAP repeat-containing 2 (BIRC2) and tumor necrosis factor receptor 1-associated death domain protein (TRADD) have been reported to be highly expressed in RA, while their specific roles during RA progression remain unclear. This study aims to explore the specific regulation of BIRC2/TRADD during the progression of RA. METHODS: C28/I2 cells were stimulated by lipopolysaccharide (LPS) to establish an in vitro RA cellular model. The expression level of BIRC2 and TRADD was examined by quantitative real-time polymerase chain reaction and western blot. Cell Counting Kit-8 and flow cytometry assays were performed to examine cell viability and necroptosis, respectively. The oxidative stress markers were detected using commercial kits, and the pro-inflammatory cytokines were measured by ELISA assay. The interaction between BIRC2 and TRADD was verified by co-immunoprecipitation assay. RESULTS: BIRC2 and TRADD were discovered to be highly expressed in LPS-mediated C28/I2 cells. BIRC2 knockdown was demonstrated to inhibit LPS-induced cell viability loss, necroptosis, oxidative stress, and inflammation in C28/I2 cells. BIRC2 could interact with TRADD and positively regulate TRADD expression. In addition, the protective role of BIRC2 knockdown against LPS-mediated injuries in C28/I2 cells was partly weakened by TRADD overexpression. CONCLUSION: In summary, BIRC2 knockdown alleviated necroptosis, oxidative stress, and inflammation in LPS-mediated C28/I2 cells, which might correlate to the regulatory role of TRADD, indicating a novel target for the treatment of RA.

cIAPs control RIPK1 kinase activity-dependent and -independent cell death and tissue inflammation.

Cellular inhibitor of apoptosis proteins (cIAPs) are RING-containing E3 ubiquitin ligases that ubiquitylate receptor-interacting protein kinase 1 (RIPK1) to regulate TNF signalling. Here, we established mice simultaneously expressing enzymatically inactive cIAP1/2 variants, bearing mutations in the RING domains of cIAP1/2 (cIAP1/2 mutant RING, cIAP1/2MutR ). cIap1/2MutR/MutR mice died during embryonic development due to RIPK1-mediated apoptosis. While expression of kinase-inactive RIPK1D138N rescued embryonic development, Ripk1D138N/D138N /cIap1/2MutR/MutR mice developed systemic inflammation and died postweaning. Cells expressing cIAP1/2MutR and RIPK1D138N were still susceptible to TNF-induced apoptosis and necroptosis, implying additional kinase-independent RIPK1 activities in regulating TNF signalling. Although further ablation of Ripk3 did not lead to any phenotypic improvement, Tnfr1 gene knock-out prevented early onset of systemic inflammation and premature mortality, indicating that cIAPs control TNFR1-mediated toxicity independent of RIPK1 and RIPK3. Beyond providing novel molecular insights into TNF-signalling, the mouse model established in this study can serve as a useful tool to further evaluate ongoing therapeutic protocols using inhibitors of TNF, cIAPs and RIPK1.

MicroRNAs Regulate Inhibitor of Apoptosis Proteins (IAPs) in Colorectal Cancer.

Colorectal cancer (CRC) is the second most common cause of cancer mortality, with approximately 1.9 million new cases and 0.9 million deaths globally in 2020. One of the potential ways to treat colorectal cancer may be through the use of molecular methods to induce cell apoptosis. Apoptosis is a natural cellular event that regulates the growth and proliferation of body cells and prevents cancer. In this pathway, several molecules are involved; one group promotes this process, and some molecules that are representative of inhibitors of apoptosis proteins (IAPs) inhibit apoptosis. The most important human IAPs include c-IAP1, c-IAP2, NAIP, Survivin, XIAP, Bruce, ILP-2, and Livin. Several studies have shown that the inhibition of IAPs may be useful in cancer treatment. MicroRNAs (miRNAs) may be effective in regulating the expression of various proteins, including those of the IAPs family; they are a large subgroup of non-coding RNAs that are evolutionarily conserved. Therefore, in this review, the miRNAs that may be used to target IAPs in colorectal cancer were discussed.

Molecular basis for nuclear accumulation and targeting of the inhibitor of apoptosis BIRC2.

The inhibitor of apoptosis protein BIRC2 regulates fundamental cell death and survival signaling pathways. Here we show that BIRC2 accumulates in the nucleus via binding of its second and third BIR domains, BIRC2BIR2 and BIRC2BIR3, to the histone H3 tail and report the structure of the BIRC2BIR3-H3 complex. RNA-seq analysis reveals that the genes involved in interferon and defense response signaling and cell-cycle regulation are most affected by depletion of BIRC2. Overexpression of BIRC2 delays DNA damage repair and recovery of the cell-cycle progression. We describe the structural mechanism for targeting of BIRC2BIR3 by a potent but biochemically uncharacterized small molecule inhibitor LCL161 and demonstrate that LCL161 disrupts the association of endogenous BIRC2 with H3 and stimulates cell death in cancer cells. We further show that LCL161 mediates degradation of BIRC2 in human immunodeficiency virus type 1-infected human CD4+ T cells. Our findings provide mechanistic insights into the nuclear accumulation of and blocking BIRC2.

Survivin Expression in Luminal Breast Cancer and Adjacent Normal Tissue for Immuno-Oncology Applications.

Survivin (BIRC5) is a tumor-associated antigen (TAA) overexpressed in various tumors but present at low to undetectable levels in normal tissue. Survivin is known to have a high expression in breast cancer (e.g., Ductal Carcinoma in situ (DCIS) and triple negative breast cancer). Previous studies have not compared survivin expression levels in DCIS tumor samples to levels in adjacent, normal breast tissue from the same patient. To ensure the effective use of survivin as a target for T cell immunotherapy of breast cancer, it is essential to ascertain the varying levels of survivin expression between DCIS tumor tissue samples and the adjacent normal breast tissue taken from the same patient simultaneously. Next-generation sequencing of RNA (RNA-seq) in normal breast tissue and tumor breast tissue from five women presenting with DCIS for lumpectomy was used to identify sequence variation and expression levels of survivin. The identity of both tumor and adjacent normal tissue samples were corroborated by histopathology. Survivin was overexpressed in human breast tissue tumor samples relative to the corresponding adjacent human normal breast tissue. Wild-type survivin transcripts were the predominant species identified in all tumor tissue sequenced. This study demonstrates upregulated expression of wild type survivin in DCIS tumor tissue versus normal breast tissue taken from the same patient at the same time, and provides evidence that developing selective cytotoxic T lymphocyte (CTL) immunotherapy for DCIS targeting survivin warrants further study.

Targeting Upregulated cIAP2 in SOX10-Deficient Drug Tolerant Melanoma.

Drug tolerance and minimal residual disease (MRD) are likely to prelude acquired resistance to targeted therapy. Mechanisms that allow persister cells to survive in the presence of targeted therapy are being characterized but selective vulnerabilities for these subpopulations remain uncertain. We identified cellular inhibitor of apoptosis protein 2 (cIAP2) as being highly expressed in SOX10-deficient drug tolerant persister (DTP) melanoma cells. Here, we show that cIAP2 is sufficient to induce tolerance to MEK inhibitors, likely by decreasing the levels of cell death. Mechanistically, cIAP2 is upregulated at the transcript level in SOX10-deficient cells and the AP-1 complex protein, JUND, is required for its expression. Using a patient-derived xenograft model, we demonstrate that treatment with the cIAP1/2 inhibitor, birinapant, during the MRD phase delays the onset of resistance to BRAF inhibitor and MEK inhibitor combination therapy. Together, our data suggest that cIAP2 upregulation in SOX10-deficient subpopulations of melanoma cells induces drug tolerance to MAPK targeting agents and provides a rationale to test a novel therapeutical approach to target MRD.

Differential regulation of BIRC2 and BIRC3 expression by inflammatory cytokines and glucocorticoids in pulmonary epithelial cells.

Roles for the baculoviral inhibitor of apoptosis repeat-containing (BIRC) genes, BIRC2 and BIRC3, may include signaling to the inflammatory transcription factor, nuclear factor-κB (NF-κB) and protection from cell death. However, distinct functions for each BIRC are not well-delineated. Given roles for the epithelium in barrier function and host defence, BIRC2 and BIRC3 expression was characterized in pulmonary epithelial cell lines and primary human bronchial epithelial cells (pHBECs) grown as undifferentiated cells in submersion culture (SC) or as highly differentiated cells at air-liquid interface (ALI). In A549 cells, interleukin-1ß (IL1B) and tumor necrosis factor α (TNF) induced BIRC3 mRNA (~20-50-fold), with maximal protein expression from 6-24 h. Similar effects occurred in BEAS-2B and Calu-3 cells, as well as SC and ALI pHBECs. BIRC2 protein was readily detected in unstimulated cells, but was not markedly modulated by IL1B or TNF. Glucocorticoids (dexamethasone, budesonide) modestly increased BIRC3 mRNA and protein, but showed little effect on BIRC2 expression. In A549 cells, BIRC3 mRNA induced by IL1B was unchanged by glucocorticoids and showed supra-additivity with TNF-plus-glucocorticoid. Supra-additivity was also evident for IL1B-plus-budesonide induced-BIRC3 in SC and ALI pHBECs. Using A549 cells, IL1B- and TNF-induced BIRC3 expression, and to a lesser extent, BIRC2, was prevented by NF-κB inhibition. Glucocorticoid-induced BIRC3 expression was prevented by silencing and antagonism of the glucocorticoid receptor. Whereas TNF, but not IL1B, induced degradation of basal BIRC2 and BIRC3 protein, IL1B- and TNF-induced BIRC3 protein remained stable. Differential regulation by cytokines and glucocorticoids shows BIRC2 protein expression to be consistent with roles in rapid signaling events, whereas cytokine-induced BIRC3 may be more important in later effects. While TNF-induced degradation of both BIRCs may restrict their activity, cytokine-enhanced BIRC3 expression could prime for its function. Finally, shielding from glucocorticoid repression, or further enhancement by glucocorticoid, may indicate a key protective role for BIRC3.

LCL161 enhances expansion and survival of engineered anti-tumor T cells but is restricted by death signaling.

Background: The genesis of SMAC mimetic drugs is founded on the observation that many cancers amplify IAP proteins to facilitate their survival, and therefore removal of these pathways would re-sensitize the cells towards apoptosis. It has become increasingly clear that SMAC mimetics also interface with the immune system in a modulatory manner. Suppression of IAP function by SMAC mimetics activates the non-canonical NF-κB pathway which can augment T cell function, opening the possibility of using SMAC mimetics to enhance immunotherapeutics. Methods: We have investigated the SMAC mimetic LCL161, which promotes degradation of cIAP-1 and cIAP-2, as an agent for delivering transient costimulation to engineered BMCA-specific human TAC T cells. In doing so we also sought to understand the cellular and molecular effects of LCL161 on T cell biology. Results: LCL161 activated the non-canonical NF-κB pathway and enhanced antigen-driven TAC T cell proliferation and survival. Transcriptional profiling from TAC T cells treated with LCL161 revealed differential expression of costimulatory and apoptosis-related proteins, namely CD30 and FAIM3. We hypothesized that regulation of these genes by LCL161 may influence the drug's effects on T cells. We reversed the differential expression through genetic engineering and observed impaired costimulation by LCL161, particularly when CD30 was deleted. While LCL161 can provide a costimulatory signal to TAC T cells following exposure to isolated antigen, we did not observe a similar pattern when TAC T cells were stimulated with myeloma cells expressing the target antigen. We questioned whether FasL expression by myeloma cells may antagonize the costimulatory effects of LCL161. Fas-KO TAC T cells displayed superior expansion following antigen stimulation in the presence of LCL161, suggesting a role for Fas-related T cell death in limiting the magnitude of the T cell response to antigen in the presence of LCL161. Conclusions: Our results demonstrate that LCL161 provides costimulation to TAC T cells exposed to antigen alone, however LCL161 did not enhance TAC T cell anti-tumor function when challenged with myeloma cells and may be limited due to sensitization of T cells towards Fas-mediated apoptosis.

The expanding role of IAP antagonists for the treatment of head and neck cancer.

Inhibitors of apoptosis proteins (IAPs) inhibit the intrinsic and extrinsic cell death pathways, promoting cell survival. Antagonists of these pathways are under study as anti-cancer therapeutics. A high proportion of head and neck squamous cell carcinomas (HNSCCs) have genomic alterations in IAP pathways, resulting in the dysregulation of cell death pathways and rendering them susceptible to IAP antagonist therapy. Preclinical studies suggest IAP antagonists, also known as second mitochondria-derived activator of caspases mimetics, may be effective treatments for HNSCC, especially when combined with radiation. Mechanistic studies have shown both molecular mechanisms (i.e., enhanced cell death) and immune mechanisms (e.g., immunogenic cell death and T-cell activation), underlying the efficacy of these drugs in preclinical models. Phase I/II clinical trials have shown promising results, portending a future where this class of targeted therapies becomes incorporated into the treatment paradigm for head and neck cancers. IAP antagonists have shown great promise for head and neck cancer, especially in combination with radiation therapy. Here, we review recent preclinical and clinical studies on the use of these novel targeted agents for head and neck cancer.

Survivin expression at the mRNA level in tumors and the protein concentration in the serum and peritoneal fluid in patients with serous ovarian tumors.

OBJECTIVES: Ovarian cancer is one of the gynecological cancers that have the worst prognosis. The expression of the proteins from the IAP family (inhibitor of apoptosis protein), including survivin, is observed in many types of cancer. The aim of the study was to evaluate survivin at the mRNA level in tumors and the protein concentration in the serum and peritoneal fluid of patients with serous ovarian cancer in order to assess the relationship between the concentration of survivin and the histological subtypes of cancer. MATERIAL AND METHODS: The study group consisted of 55 women, including patients with serous ovarian cancer (n = 30, nine low-grade serous carcinoma LGSC, 21 high-grade serous carcinoma HGSC), serous cysts (n = 10) and the control group (n = 15). The concentration of protein in the peritoneal fluid and serum was assessed using ELISA tests. The expression of survivin gene BIRC5 in the tumors was assessed using the RT-qPCR method. RESULTS: The data that was obtained indicated that the concentration of survivin was higher in the serum of the women with serous ovarian cancer compared those that had benign tumors (p < 0.05) and the control group (p < 0.001). The survivin concentration was also higher in both the serum and peritoneal fluid in the HGSC group compared to the LGSC group (p < 0.001). The mRNA level was highest in the HGSC group, and there was a statistically significant difference compared to those in the benign tumor group and HGSC group ( p < 0.05). CONCLUSIONS: The observed changes prove that the expression level increases significantly in HGSC in both the protein and mRNA levels. Based on these findings, it can be assumed that assessing this parameter could be a useful additional indicator of the progression and differentiation of this type of cancer. However, this requires further research in a larger group of patients and possibly in other types of ovarian cancer.

X-linked inhibitor of apoptosis protein represents a promising therapeutic target for relapsed/refractory ALL.

Acute lymphoblastic leukemia (ALL) represents the most frequent malignancy in children, and relapse/refractory (r/r) disease is difficult to treat, both in children and adults. In search for novel treatment options against r/r ALL, we studied inhibitor of apoptosis proteins (IAP) and Smac mimetics (SM). SM-sensitized r/r ALL cells towards conventional chemotherapy, even upon resistance against SM alone. The combination of SM and chemotherapy-induced cell death via caspases and PARP, but independent from cIAP-1/2, RIPK1, TNFα or NF-κB. Instead, XIAP was identified to mediate SM effects. Molecular manipulation of XIAP in vivo using microRNA-30 flanked shRNA expression in cell lines and patient-derived xenograft (PDX) models of r/r ALL mimicked SM effects and intermediate XIAP knockdown-sensitized r/r ALL cells towards chemotherapy-induced apoptosis. Interestingly, upon strong XIAP knockdown, PDX r/r ALL cells were outcompeted in vivo, even in the absence of chemotherapy. Our results indicate a yet unknown essential function of XIAP in r/r ALL and reveal XIAP as a promising therapeutic target for r/r ALL.

Exploring the Role of the Inhibitor of Apoptosis BIRC6 in Breast Cancer: A Database Analysis.

PURPOSE: The aim of the present work was to investigate the role of apoptosis inhibitor BIRC6 (baculoviral IAP repeat-containing protein 6) in breast cancer (BC), focusing particularly on its involvement in the metastatic cascade. METHODS: We analyzed BIRC6 mRNA expression levels and copy number variations in three BC databases from The Cancer Genome Atlas comparing clinical and molecular attributes. Genomic analysis was performed using the cBioPortal platform, whereas transcriptomic studies (mRNA expression levels, correlation heatmaps, survival plots, and gene ontology) were performed using USC Xena and R. Statistical significance was set at P < .05. RESULTS: Our bioinformatic analyses showed that there was a differential expression of BIRC6 in cancer samples when compared with normal samples. Copy number variations that involve amplification and gain of BIRC6 gene were correlated with negative hormone receptor tumors, higher prognostic indexes, younger age at diagnosis, and both chemotherapy and radiotherapy administration. Transcriptomic and gene ontology analyses showed that, under conditions of high BIRC6 mRNA levels, there are differential expression patterns in apoptotic, proliferation, and metastatic pathways. CONCLUSION: In summary, our in silico data suggest that BIRC6 plays an antiapoptotic, pro-proliferative, and apparent prometastatic role and could be a relevant molecular target for treatment of BC tumors.

Hydrogen gas promotes apoptosis of lung adenocarcinoma A549 cells through X-linked inhibitor of apoptosis and baculoviral inhibitor of apoptosis protein repeat-containing 3.

Objective: Lung cancer is currently the cancer with the highest incidence and death toll worldwide. Hydrogen gas has been found to affect a variety of diseases; however, the effect of hydrogen gas on patients with lung cancer has not been reported. Therefore, we determined the effect of hydrogen gas on apoptosis of lung adenocarcinoma in vivo and in vitro. Materials and Methods: A549 cells in the logarithmic phase were treated with 20%, 40%, or 60% hydrogen gas. Cell apoptosis was evaluated by flow cytometry. The A549 cell suspension was inoculated into 15 nude mice. The mice were randomly divided into control, hydrogenation (inhalation of 60% hydrogen gas), and cisplatin groups (intraperitoneal injection of cisplatin [4 mg/kg]). After 3 weeks, the tumor tissue was removed and measured. We identified differentially expressed genes by transcriptional profiling. The levels of X-linked inhibitor of apoptosis (XIAP), baculoviral inhibitor of apoptosis protein repeat-containing 3 (BIRC3), and BCL2-associated X and apoptosis regulator (BAX) protein expression were detected by Western blotting and immunohistochemistry. Results: Compared with the control group, the apoptosis rates in the 20%, 40%, and 60% hydrogen gas groups were significantly increased (P < 0.01). The levels of XIAP and BIRC3 protein expression were clearly decreased in the hydrogen gas group compared to the control group. Moreover, cisplatin and hydrogen gas reduced the tumor volume in nude mice (P < 0.01). Transcriptome sequencing showed that XIAP, BIRC2, BIRC3, BAX, PIK3CD, and ATM were related to apoptosis. Hydrogen gas further decreased the levels of XIAP and BIRC3 expression than in nude mice (P < 0.01). Conclusion: Hydrogen gas promoted apoptosis of A549 cells by reducing the expression of XIAP and BIRC3 protein.

Survivin in Breast Cancer: A Review.

Breast cancer is the most frequently diagnosed cancer in women and ranks second among causes for cancer-related death in women. Gene technology has led to the recognition that breast cancer is a heterogeneous disease composed of different biological subtypes, and genetic profiling enables the response to chemotherapy to be predicted. This fact emphasizes the importance of selecting sensitive diagnostic and prognostic markers in the early disease stage and more efficient targeted treatments for this disease. One such prognostic marker appears to be survivin. Many studies have shown that survivin is strongly expressed in different types of cancers. Its overexpression has been demonstrated in breast cancer, and high activity of the survivin gene has been associated with a poor prognosis and worse survival rates.

Prognostic Significance of the BIRC2-BIRC3 Gene Signature in Head and Neck Squamous Cell Carcinoma.

BACKGROUND/AIM: Head and neck squamous cell carcinoma (HNSCC) has poor prognosis, with survival rates that have not significantly improved over the past several decades. Therefore, prediction of HNSCC prognosis is of clinical importance. Baculoviral IAP Repeat containing 2 (BIRC2) and Baculoviral IAP Repeat containing 3 (BIRC3) are involved in oncogenic activity by modulating cell proliferation, apoptosis and invasion in HNSCC. This study aimed to develop and validate a predictive gene signature for BIRC2 and BIRC3. MATERIALS AND METHODS: The genomic copy number and gene expression for BIRC2 and BIRC3 were systematically explored in patients with HNSCC to investigate the clinical relevance of BIRC2 and BIRC3 activation. A prognostic signature was developed based on correlations associated with BIRC2 and BIRC3 mRNA expression and copy number alterations. Hierarchical clustering was used to classify the clusters (Clusters 1 and 2). Moreover, independent validation of the BIRC2-BIRC3 gene signature was performed using the Leipzig, MDACC, FHCRC, and KHU datasets. To explore the biological functions of the BIRC2-BIRC3 gene signature, string analysis and pathway annotation were also performed. RESULTS: BIRC2-BIRC3 gene signature-derived cluster 2 patients exhibited significantly poor survival. This signature also predicted survival in three independent cohorts. Interestingly, the BIRC2-BIRC3 gene signature additionally permitted the identification of survival in advanced tumor stages with excellent accuracy in all three cohorts. Multivariate Cox regression analysis identified that the BIRC2-BIRC3 signature was an independent predictor associated with the survival of patients with HNSCC. Moreover, Inhibition of BIRC2 modulated the NF-B signaling pathway via upregulation of CBR1 expression. CONCLUSION: The BIRC2-BIRC3 gene signature was found to be associated with the prognosis of HNSCC. Thus, BIRC2 and BIRC3 could be potential targets for improving HNSCC prognosis.