The upregulation and transcriptional regulatory mechanisms of Extra spindle pole bodies like 1 in bladder cancer: An immunohistochemistry and high-throughput screening Evaluation.

Background: This study aimed to explore the expression level and transcriptional regulation mechanism of Extra Spindle Pole Bodies Like 1 (ESPL1) in bladder cancer (BC). Methods: A multicentre database of samples (n = 1391) was assayed for ESPL1 mRNA expression in BC and validated at the protein level by immunohistochemical (IHC) staining of in-house samples (n = 202). Single-cell sequencing (scRNA-seq) analysis and enrichment analysis explored ESPL1 distribution and their accompanying molecular mechanisms. ATAC-seq, ChIP-seq and Hi-C data from multiple platforms were used to investigate ESPL1 upstream transcription factors (TFs) and potential epigenetic regulatory mechanisms. Immune-related analysis, drug sensitivity and molecular docking of ESPL1 were also calculated. Furthermore, upstream microRNAs and the binding sites of ESPL1 were predicted. The expression level and early screening efficacy of miR-299-5p in blood (n = 6625) and tissues (n = 537) were examined. Results: ESPL1 was significantly overexpressed at the mRNA level (p < 0.05, SMD = 0.75; 95 % CI = 0.09, 1.40), and IHC staining of in-house samples verified this finding (p < 0.0001). ESPL1 was predominantly distributed in BC epithelial cells. Coexpressed genes of ESPL1 were enriched in cell cycle-related signalling pathways, and ESPL1 might be involved in the communication between epithelial and residual cells in the Hippo, ErbB, PI3K-Akt and Ras signalling pathways. Three TFs (H2AZ, IRF5 and HIF1A) were detected upstream of ESPL1 and presence of promoter-super enhancer and promoter-typical enhancer loops. ESPL1 expression was correlated with various immune cell infiltration levels. ESPL1 expression might promote BC growth and affect the sensitivity and therapeutic efficacy of paclitaxel and gemcitabine in BC patients. As an upstream regulator of ESPL1, miR-299-5p expression was downregulated in both the blood and tissues, possessing great potential for early screening. Conclusions: ESPL1 expression was upregulated in BC and was mainly distributed in epithelial cells. Elevated ESPL1 expression was associated with TFs at the upstream transcription start site (TSS) and distant chromatin loops of regulatory elements. ESPL1 might be an immune-related predictive and diagnostic marker for BC, and the overexpression of ESPL1 played a cancer-promoting role and affected BC patients' sensitivity to drug therapy. miR-299-5p was downregulated in BC blood and tissues and was also expected to be a novel marker for early screening.

Upregulation of ESPL1 is associated with poor prognostic outcomes in endometrial cancer.

BACKGROUND: Extra spindle pole bodies-like 1 (ESPL1) is known to play a crucial role in the segregation of sister chromatids during mitosis. Overexpression of ESPL1 is considered to have oncogenic effects in various human cancers. However, the specific biological function of ESPL1 in endometrial cancer (EC) remains unclear. METHODS: The TCGA and GEO databases were utilized to assess the expression of ESPL1 in EC. Immunohistochemistry was utilized to detect separase expression in EC samples. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate the diagnostic and prognostic significance of ESPL1 in EC. Gene Set Enrichment Analysis (GSEA) was employed to explore the potential signaling pathway of ESPL1 in EC. Cell proliferation and colony formation ability were analyzed using CCK-8 and colony formation assay. RESULTS: Our analysis revealed that ESPL1 is significantly upregulated in EC, and its overexpression is associated with advanced clinical characteristics and unfavourable prognostic outcomes. Suppression of ESPL1 attenuated proliferation of EC cell line. CONCLUSION: The upregulation of ESPL1 is associated with advanced disease and poor prognosis in EC patients. These findings suggest that ESPL1 has the potential to serve as a diagnostic and prognostic biomarker in EC, highlighting its significance in the management of EC patients.

The expression of ESPL1 was higher in EC tissue than normal endometrial tissue.ESPL1 could be a potential prognostic marker for EC.

PAX2 mediated upregulation of ESPL1 contributes to cisplatin resistance in bladder cancer through activating the JAK2/STAT3 pathway.

Extra spindle-polar body like 1 (ESPL1) is associated with the development of a variety of cancers, including bladder cancer, and is closely related to chemoresistance. In this study, we aimed to reveal the role of ESPL1 in bladder cancer progression and cisplatin (DDP) resistance. First, ESPL1 was found to be highly expressed in tumor tissues and cells of bladder cancer, and more highly expressed in cisplatin resistant tumor tissues or cells. The binding of PAX2 in ESPL1 promoter region was predicted by Jaspar database and verified by Ch-IP analysis and the luciferase reporter gene assay. Next, cisplatin-resistant T24 cells (T24/DDP) were established and transfected with ESPL1 siRNA (si-ESPL1) or overexpression vector (pcDNA-ESPL1) or co-transfected with PAX2 siRNA (si-PAX2) or overexpression vector (pcDNA-PAX2), and then treated with DDP or AG490, an inhibitor of JAK2. The results showed that silencing ESPL1 significantly reduced T24/DDP cell viability, colony formation and invasion, enhanced sensitivity to DDP, and induced cell apoptosis. Silencing PAX2 decreased ESPL1 expression, enhanced sensitivity to DDP, and induced apoptosis of T24/DDP cells, and inhibited activation of JAK2/STAT3 pathway. Overexpressing ESPL1 reversed the effect of PAX2 silencing on T24/DDP cells, while AG490 counteracted the reversal effect of overexpressing ESPL1. Finally, a xenograft tumor model was established and found that silencing ESPL1 or DDP treatment inhibited tumor growth, while silencing ESPL1 combined with DDP treatment had the best effect. In summary, this study suggested that PAX2-mediated ESPL1 transcriptional activation enhanced cisplatin resistance in bladder cancer by activating JAK2/STAT3 pathway.

Genome-wide CRISPR screen identifies ESPL1 limits the response of gastric cancer cells to apatinib.

Apatinib was the first anti-angiogenic agent approved for treatment of metastatic gastric cancer (GC). However, the emergence of resistance was inevitable. Thus investigating new and valuable off-target effect of apatinib directly against cancer cells is of great significance. Here, we identified extra spindle pole bodies-like 1 (ESPL1) was responsible for apatinib resistance in GC cells through CRISPR genome-wide gain-of-function screening. Loss of function studies further showed that ESPL1 inhibition suppressed cell proliferation, migration and promoted apoptosis in vitro, and accordingly ESPL1 knockdown sensitized GC cells to apatinib. In addition, we found ESPL1 interacted with mouse double minute 2 (MDM2), a E3 ubiquitin protein ligase, and the combination of MDM2 siRNA with apatinib synergistically ameliorated the resistance induced by ESPL1 overexpression. In summary, our study indicated that ESPL1 played a critical role in apatinib resistance in GC cells. Inhibition of MDM2 could rescue the sensitivity of GC cells to apatinib and reverse ESPL1-mediated resistance.

Correlation Between Serum ESPL1 and Hepatitis B Virus-related Hepatocellular Carcinoma Histological Grade: A Chinese Single-center Case-control Study.

BACKGROUND/AIM: Serum markers to determine the histological grade of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) are still limited. This study aimed to investigate if serum extra spindle pole bodies-like 1 (ESPL1) protein could reflect the histological grade of HBV-related HCC. MATERIALS AND METHODS: A total of 154 patients with HBV-related HCC were enrolled in the experimental group and 41 non-HBV-related patients in the control. Enzyme-linked immunosorbent assay was used to detect serum ESPL1 levels. The differences in serological ESPL1, alpha-fetoprotein (AFP), and des-gamma-carboxy prothrombin (DCP) were compared between the two groups. HCC tumor diameter was measured, and pathological examination was performed to compare the relationship between ESPL1, AFP, and DCP and tumor size and histological grade. RESULTS: Serum AFP and DCP levels showed no significant difference between experimental group and control group, and increased when the tumor diameter increased but were not related to HCC histological grade. Serological ESPL1 levels were higher in the experimental group than those in the control group, and positively correlated with the histological grade. In the experimental group, tumor size and histological grade were almost independent (Kappa=0.000); patients with medium size tumors had the highest serum ESPL1 levels and the highest proportion of poorly differentiated carcinomas, whereas 75.6% of patients with small size tumors had moderately differentiated carcinomas and only 20% well differentiated carcinomas. CONCLUSION: Serum ESPL1 can reflect the malignant degree of HBV-related HCC and is helpful in identifying small size HCC tumors.

Genome-wide DNA methylation and transcriptome analyses reveal important epigenetic genes associated with valgus-varus deformity in broilers.

1. Valgus-varus deformity (VVD) is a common leg bone problem in broilers that causes serious economic losses to the breeding industry. The genetic aetiology of VVD is not clear, which restricts the genetic control of VVD.2. In this study, knee cartilage of 35-day-old VVD and normal broilers was sequenced by whole-genome bisulphite sequencing (WGBS). The unique whole-genome DNA methylation profile of VVD broilers was described, and the methylation data and transcription data were used for joint analysis.3. The mean methylation level of the VVD group was greater than that in the normal group. A total of 4315 differentially methylated regions (DMRs) were detected from methylation data, with the highest DMR density on chromosomes 25, 27, 31 and 33. DMRs were mainly located in introns, which accounted for more than 60%, followed by promoter and exon regions.4. A total of 2326 differentially methylated genes (DMGs) were identified from DMRs, including 1159 genes with upregulated DMRs, 936 genes with downregulated DMRs, and 231 genes with two types of DMRs.5. The ESPL1 gene may be an important epigenetic gene of VVD. The methylation of particular CpG17, CpG18 and CpG19 sites in the promoter region of the ESPL1 gene may hinder the binding of transcription factors and promoters and increase the expression of ESPL1.

Gene Expression Pattern of ESPL1, PTTG1 and PTTG1IP Can Potentially Predict Response to TKI First-Line Treatment of Patients with Newly Diagnosed CML.

The achievement of major molecular response (MMR, BCR::ABL1 ≤ 0.1% IS) within the first year of treatment with tyrosine kinase inhibitors (TKI) is a milestone in the therapeutic management of patients with newly diagnosed chronic myeloid leukemia (CML). We analyzed the predictive value of gene expression levels of ESPL1/Separase, PTTG1/Securin and PTTG1IP/Securin interacting protein for MMR achievement within 12 months. Relative expression levels (normalized to GUSB) of ESPL1, PTTG1 and PTTG1IP in white blood cells of patients (responders n = 46, non-responders n = 51) at the time of diagnosis were comparatively analyzed by qRT-PCR. 3D scatter plot analysis combined with a distance analysis performed with respect to a commonly calculated centroid center resulted in a trend to larger distances for non-responders compared to the responder cohort (p = 0.0187). Logistic regression and analysis of maximum likelihood estimates revealed a positive correlation of distance (cut-off) with non-achieving MMR within 12 months (p = 0.0388, odds ratio 1.479, 95%CI: 1.020 to 2.143). Thus, 10% of the tested non-responders (cut-off ≥ 5.9) could have been predicted already at the time of diagnosis. Future scoring of ESPL1, PTTG1 and PTTG1IP transcript levels may be a helpful tool in risk stratification of CML patients before initiation of TKI first = line treatment.

Pan-Cancer analysis and experimental validation identify the oncogenic nature of ESPL1: Potential therapeutic target in colorectal cancer.

Introduction: Extra spindle pole bodies like 1 (ESPL1) are required to continue the cell cycle, and its primary role is to initiate the final segregation of sister chromatids. Although prior research has revealed a link between ESPL1 and the development of cancer, no systematic pan-cancer analysis has been conducted. Combining multi-omics data with bioinformatics, we have thoroughly described the function of ESPL1 in cancer. In addition, we examined the impact of ESPL1 on the proliferation of numerous cancer cell lines. In addition, the connection between ESPL1 and medication sensitivity was verified using organoids obtained from colorectal cancer patients. All these results confirm the oncogene nature of ESPL1. Methods: Herein, we downloaded raw data from numerous publicly available databases and then applied R software and online tools to explore the association of ESPL1 expression with prognosis, survival, tumor microenvironment, tumor heterogeneity, and mutational profiles. To validate the oncogene nature of ESPL1, we have performed a knockdown of the target gene in various cancer cell lines to verify the effect of ESPL1 on proliferation and migration. In addition, patients' derived organoids were used to verify drug sensitivity. Results: The study found that ESPL1 expression was markedly upregulated in tumorous tissues compared to normal tissues, and high expression of ESPL1 was significantly associated with poor prognosis in a range of cancers. Furthermore, the study revealed that tumors with high ESPL1 expression tended to be more heterogeneous based on various tumor heterogeneity indicators. Enrichment analysis showed that ESPL1 is involved in mediating multiple cancer-related pathways. Notably, the study found that interference with ESPL1 expression significantly inhibited the proliferation of tumor cells. Additionally, the higher the expression of ESPL1 in organoids, the greater the sensitivity to PHA-793887, PAC-1, and AZD7762. Discussion: Taken together, our study provides evidence that ESPL1 may implicate tumorigenesis and disease progression across multiple cancer types, highlighting its potential utility as both a prognostic indicator and therapeutic target.

Association of the Timeless Gene with Prognosis and Clinical Characteristics of Human Lung Cancer.

(1) Background: As the most common malignant tumor type worldwide, it is necessary to identify novel potential prognostic biomarkers to improve the poor prognosis of lung cancer. The Timeless gene, a circadian rhythm-related gene, is associated with several types of cancer. However, studies analyzing the clinical significance of the Timeless gene in patients with lung cancer are currently limited. (2) Methods: In the present study, the expression levels and prognostic potential of the Timeless gene and its co-expressed genes in different subtypes of lung cancer were explored using multiple bioinformatics approaches. The correlations between the Timeless gene and its co-expressed genes were validated using A549 and NCI-H226 cells by transfecting them with expression vectors and analyses using Western blot and reverse transcription-quantitative PCR. (3) Results: The Oncomine and GEPIA database analyses indicated that the expression of the Timeless gene was significantly higher in lung cancer as compared to that in the normal tissue. Using the UALCAN database, significant differences in Timeless gene expression were determined among different stages of lung cancer and between genders. A Kaplan-Meier plotter analysis indicated that high expression of the Timeless gene was associated with poor overall survival (OS) and progression-free survival (PFS) of patients with lung cancer. In the cBioPortal and GEPIA database analyses, extra spindle pole bodies like 1 (ESPL1) was the top correlated gene of Timeless in patients with lung cancer. Similar to the Timeless gene, high expression of the ESPL1 gene was also associated with poor OS and PFS. Of note, overexpression of the Timeless gene increased the expression level of ESPL1 at both the mRNA and protein levels. (4) Conclusion: The present study explored the clinical significance of the Timeless gene and its correlated gene ESPL1 in patients with lung cancer, thereby providing a potential therapeutic target for lung cancer.

Let-7c-5p Restrains Cell Growth and Induces Apoptosis of Lung Adenocarcinoma Cells via Targeting ESPL1.

Lung adenocarcinoma (LUAD) is a predominant malignancy, and its high mortality prompts us to incessantly probe the relevant targeted treatment. This work intended to study the molecular mechanism of ESPL1 in LUAD. Bioinformatics analysis was performed for pan-cancer and prognosis analysis as well as target gene prediction. Expression of ESPL1 mRNA and let-7c-5p was determined via qRT-PCR, and western blot was employed to detect protein level of ESPL1. Dual-luciferase reporter gene method verified the interaction between ESPL1 and let-7c-5p. Thereafter, CCK-8, wound healing, Transwell, and flow cytometry assays were utilized to investigate proliferation, migration, and apoptosis of LUAD cells. The results revealed that ESPL1 was upregulated in LUAD, which was associated with poor prognosis. Overexpressed ESPL1 promoted LUAD cells to invade, proliferate, and migrate. Furthermore, ESPL1 was a target gene of let-7c-5p. Let-7c-5p was downregulated in LUAD cells, and played a suppressive role in LUAD malignant development, while reversed by ESPL1. Taken together, it was posited that let-7c-5p/ESPL1 may be underlying therapeutic targets of LUAD.

ESPL1 Is a Novel Prognostic Biomarker Associated With the Malignant Features of Glioma.

Research has confirmed that extra spindle pole bodies-like 1 (ESPL1), an etiological factor, promotes the malignant progression of cancers. However, the relationship between ESPL1 and glioma has not yet been demonstrated. The purpose of this study was to reveal the potential mechanisms of ESPL1-mediated malignant glioma progression. Gene expression data and detailed clinical information of glioma cases were obtained from multiple public databases. Subsequently, a series of bioinformatics analyses were used to elucidate the effects of ESPL1 on glioma. The results demonstrated that the mRNA and protein levels of ESPL1 in glioma were higher than those in normal brain tissues. In addition, ESPL1 expression was considerably associated with the clinical and pathological features of gliomas, such as World Health Organization grade, histology, and 1p19q co-deletion status. Importantly, ESPL1 reduced the overall survival (OS) of glioma patients and had prognostic value for gliomas. Gene set enrichment analysis (GSEA) indirectly revealed that ESPL1 regulates the activation of cancer-related pathways, such as the cell cycle and base excision repair pathways. In addition, we used the Connectivity Map (CMap) database to screen three molecular drugs that inhibit ESPL1: thioguanosine, antimycin A, and zidovudine. Finally, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression levels of ESPL1 in glioma cell lines. This study plays an important role in revealing the etiology of glioma by revealing the function of ESPL1, providing a potential molecular marker for the diagnosis and treatment of glioma, especially low-grade glioma.

Serum ESPL1 Can Be Used as a Biomarker for Patients With Hepatitis B Virus-Related Liver Cancer: A Chinese Case-Control Study.

AIMS: To investigate the feasibility of serum extra spindle pole bodies-like 1 (ESPL1) used as a biomarker for patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). METHODS: 131 chronic HBV-infection patients were recruited and divided into HBV S gene integration, non-HBV S gene integration, chronic hepatitis B (CHB), HBV-related liver cirrhosis (LC) and HBV-related HCC group, 24 non-HBV-related HCC patients were selected as HCC control group, 30 people without HBV-infection as healthy control group. Serum ESPL1 were detected and compared. RESULTS: ESPL1 level of integration group was significantly higher than that of non-integration group (346.7 vs 199.6 ng/ml, P = 0.000) and healthy control group (346.7 vs 41.3 ng/ml, P = 0.000). ESPL1 level of non-integration group was significantly higher than that of healthy control group (199.6 vs 41.3 ng/ml, P = 0.000); ESPL1 levels in chronic HBV-infection related groups were increased in turn according to CHB group (95.8 ng/ml), HBV-related LC group (268.2 ng/ml), HBV-related HCC group (279.9 ng/ml) and integration group (346.7 ng/ml). Except that there was no significant difference in ESPL1 levels between HBV-related LC and HCC group (P = 0.662), pairwise comparisons between other groups showed significant differences (P < 0.05). ESPL1 level of HBV-related HCC group was significantly higher than that of non-HBV-related HCC group (279.9 vs 46.6 ng/ml, P = 0.000), there was no noticeable difference between non-HBV-related HCC and healthy control group (46.6 vs 41.3 ng/ml, P = 0.848). ESPL1 level of HBV-related HCC group after resection was significantly lower than that of before resection (178.4 vs 260.8 ng/ml, P = 0.000). CONCLUSIONS: Chronic HBV-infection patients with high ESPL1 level may indicate HBV S gene integration and is a high-risk population for HBV-related HCC. Serum ESPL1 can be used as a biomarker for screening HBV-related HCC high-risk population and monitoring recurrence.

Haploinsufficiency of cohesin protease, Separase, promotes regeneration of hematopoietic stem cells in mice.

Cohesin recently emerged as a new regulator of hematopoiesis and leukemia. In addition to cohesin, whether proteins that regulate cohesin's function have any direct role in hematopoiesis and hematologic diseases have not been fully examined. Separase, encoded by the ESPL1 gene, is an important regulator of cohesin's function. Canonically, protease activity of Separase resolves sister chromatid cohesion by cleaving cohesin subunit-Rad21 at the onset of anaphase. Using a Separase haploinsufficient mouse model, we have uncovered a novel role of Separase in hematopoiesis. We report that partial disruption of Separase distinctly alters the functional characteristics of hematopoietic stem/progenitor cells (HSPCs). Although analyses of peripheral blood and bone marrow of Espl1+/Hyp mice broadly displayed unperturbed hematopoietic parameters during normal hematopoiesis, further probing of the composition of early hematopoietic cells in Espl1+/Hyp bone marrow revealed a mild reduction in the frequencies of the Lin- Sca1+ Kit- (LSK) or LSK CD48+ CD150- multipotent hematopoietic progenitors population without a significant change in either long-term or short-term hematopoietic stem cells (HSCs) subsets at steady state. Surprisingly, however, we found that Separase haploinsufficiency promotes regeneration activity of HSCs in serial in vivo repopulation assays. In vitro colony formation assays also revealed an enhanced serial replating capacity of hematopoietic progenitors isolated from Espl1+/Hyp mice. Microarray analysis of differentially expressed genes showed that Separase haploinsufficiency in HSCs (SP-KSL) leads to enrichment of gene signatures that are upregulated in HSCs compared to committed progenitors and mature cells. Taken together, our findings demonstrate a key role of Separase in promoting hematopoietic regeneration of HSCs.

Separase activity distribution can be a marker of major molecular response and proliferation of CD34+ cells in TKI-treated chronic myeloid leukemia patients.

Separase, a cysteine endopeptidase, is a key player in mitotic sister chromatid separation, replication fork dynamics, and DNA repair. Aberrant expression and/or altered separase proteolytic activity are associated with aneuploidy, tumorigenesis, and disease progression. Since genomic instability and clonal evolution are hallmarks of progressing chronic myeloid leukemia (CML), we have comparatively examined separase proteolytic activity in TKI-treated chronic phase CML. Separase proteolytic activity was analyzed on single cell level in 88 clinical samples and in 14 healthy controls by a flow cytometric assay. In parallel, BCR-ABL1 gene expression and replication fork velocity were measured by qRT-PCR and DNA fiber assays, respectively. The separase activity distribution (SAD) value indicating the occurrence of MNCs with elevated separase proteolytic activity within samples was found to positively correlate with BCR-ABL1 gene expression levels and loss of MMR (relapse) throughout routine BCR-ABL1 monitoring. Analyses of CD34+ cells and MNCs fractionized by flow cytometric cell sorting according to their separase activity levels (H- and L-fractions) revealed that CD34+ cells with elevated separase activity levels (H-fractions) displayed enhanced proliferation/viability when compared with cells with regular (L-fraction) separase activity (mean 3.3-fold, p = 0.0011). BCR-ABL1 gene expression positivity prevailed in MNC H-fractions over L-fractions (42% vs. 8%, respectively). Moreover, expanding CD34+ cells of H-fractions showed decreased replication fork velocity compared with cells of L-fractions (p < 0.0001). Our data suggests an association between high separase activity, residual BCR-ABL1 gene expression, and enhanced proliferative capacity in hematopoietic cells within the leukemic niche of TKI-treated chronic phase CML.

High Rate of Detection of Human ESPL1-HBV S Fusion Gene in Patients With HBV-related Liver Cancer: A Chinese Case-Control Study.

AIM: It has been shown that the integration of hepatitis B virus (HBV) gene into the host genome is a high-risk factor for development of hepatocellular carcinoma (HCC). However, the relationship between HBV S-integrated human extra spindle pole bodies-like 1 (ESPL1) gene and HCC is unknown. This study was designed to detect HBV S-integrated human ESPL1 fusion gene in patients with HCC for potentially using this fusion gene as a biomarker for HCC diagnosis. PATIENTS AND METHODS: Nineteen and 70 patients with chronic hepatitis B (CHB) were recruited to the experimental and control groups, respectively, and both groups underwent an effective nucleoside/nucleotide analog therapy and follow-up for HCC occurrence for up to 11 years. HCC tissues were obtained by surgical resection from the experimental group, while liver tissues were collected by liver biopsy in the control group prior to treatment with nucleoside/nucleotide analogs. Alu polymerase chain reaction was used to assess HBV S gene integration in the liver tissues from both groups. HBV S-integrated human ESPL1 fusion gene was then detected in patients with HBV S gene integration using a gene database. RESULTS: All patients in the experimental group developed HCC, whereas no HCC was diagnosed in the control group. HBV S gene integration was identified in 12 out of 19 HCC tissues in the experimental group, giving a detection rate of 63.2%, which was significantly greater than that of 15.7% (11/70) in the control group (p<0.001). We further showed that HBV S-integrated human ESPL1 fusion gene was detected in eight patients (rate of 66.7%) among the 12 patients with HCC with HBV S gene integration in the experimental group, whereas the fusion gene was not detectable in any of the patients in the control group (p=0.001). CONCLUSION: This research demonstrates a high detection rate of HBV S-integrated human ESPL1 fusion gene in patients with HBV-related HCC and shows that this fusion gene appears to be associated with HCC development in patients with CHB. These findings suggest that HBV S-integrated human ESPL1 fusion gene may potentially serve as a biomarker for early detection of HCC in HBV-infected populations.

Biology and insights into the role of cohesin protease separase in human malignancies.

Separase, an enzyme that resolves sister chromatid cohesion during the metaphase-to-anaphase transition, plays a pivotal role in chromosomal segregation and cell division. Separase protein, encoded by the extra spindle pole bodies like 1 (ESPL1) gene, is overexpressed in numerous human cancers including breast, bone, brain, and prostate. Separase is oncogenic, and its overexpression is sufficient to induce mammary tumours in mice. Either acute or chronic overexpression of separase in mouse mammary glands leads to aneuploidy and tumorigenesis, and inhibition of separase enzymatic activity decreases the growth of human breast tumour xenografts in mice. This review focuses on the biology of and insights into the molecular mechanisms of separase as an oncogene, and its significance and implications for human cancers.

c-MYB is a transcriptional regulator of ESPL1/Separase in BCR-ABL-positive chronic myeloid leukemia.

BACKGROUND: Genomic instability and clonal evolution are hallmarks of progressing chronic myeloid leukemia (CML). Recently, we have shown that clonal evolution and blast crisis correlate with altered expression and activity of Separase, a cysteine endopeptidase that is a mitotic key player in chromosomal segregation and centriole duplication. Hyperactivation of Separase in human hematopoietic cells has been linked to a feedback mechanism that posttranslationally stimulates Separase proteolytic activity after imatinib therapy-induced reduction of Separase protein levels. METHODS AND RESULTS: In search for potential therapy-responsive transcriptional mechanisms we have investigated the role of the transcription factor c-MYB for Separase expression in CML cell lines (LAMA-84, K562, BV-173) and in clinical samples. Quantitative RT-PCR and Western blot immunostaining experiments revealed that c-MYB expression levels are decreased in an imatinib-dependent manner and positively correlate with Separase expression levels in cell lines and in clinical CML samples. RNA silencing of c-MYB expression in CML cell lines resulted in reduced Separase protein levels. Gelshift and ChIP assays confirmed that c-MYB binds to a putative c-MYB binding sequence located within the ESPL1 promoter. CONCLUSIONS: Our data suggest that ESPL1/Separase is a regulatory target of c-MYB. Therefore, c-MYB, known to be required for BCR-ABL-dependent transformation of hematopoietic progenitors and leukemogenesis, may also control the Separase-dependent fidelity of mitotic chromosomal segregation and centriole duplication essential for maintenance of genomic stability.

Antagonistic functional duality of cancer genes.

Cancer evolution is a stochastic process both at the genome and gene levels. Most of tumors contain multiple genetic subclones, evolving in either succession or in parallel, either in a linear or branching manner, with heterogeneous genome and gene alterations, extensively rewired signaling networks, and addicted to multiple oncogenes easily switching with each other during cancer progression and medical intervention. Hundreds of discovered cancer genes are classified according to whether they function in a dominant (oncogenes) or recessive (tumor suppressor genes) manner in a cancer cell. However, there are many cancer "gene-chameleons", which behave distinctly in opposite way in the different experimental settings showing antagonistic duality. In contrast to the widely accepted view that mutant NADP(+)-dependent isocitrate dehydrogenases 1/2 (IDH1/2) and associated metabolite 2-hydroxyglutarate (R)-enantiomer are intrinsically "the drivers" of tumourigenesis, mutant IDH1/2 inhibited, promoted or had no effect on cell proliferation, growth and tumorigenicity in diverse experiments. Similar behavior was evidenced for dozens of cancer genes. Gene function is dependent on genetic network, which is defined by the genome context. The overall changes in karyotype can result in alterations of the role and function of the same genes and pathways. The diverse cell lines and tumor samples have been used in experiments for proving gene tumor promoting/suppressive activity. They all display heterogeneous individual karyotypes and disturbed signaling networks. Consequently, the effect and function of gene under investigation can be opposite and versatile in cells with different genomes that may explain antagonistic duality of cancer genes and the cell type- or the cellular genetic/context-dependent response to the same protein. Antagonistic duality of cancer genes might contribute to failure of chemotherapy. Instructive examples of unexpected activity of cancer genes and "paradoxical" effects of different anticancer drugs depending on the cellular genetic context/signaling network are discussed.