IDO1 plays a tumor-promoting role via MDM2-mediated suppression of the p53 pathway in diffuse large B-cell lymphoma.
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SUBMITTER: Sun C
PROVIDER: S-EPMC9237101 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundCell-division cycle 20 (CDC20) is overexpressed in a variety of tumor cells and is negatively regulated by wild-type p53 (wtp53). Our previous study uncovered that CDC20 was upregulated and associated with poor outcome in diffuse large B-cell lymphoma (DLBCL) based on bioinformatics analysis. Dysregulation of the MDM2-p53 is a major mechanism to promote DLBCL. Thus, we hypothesized that CDC20 could be a downstream gene of the MDM2-p53 signaling pathway. However, the clinical significance and mechanistic role of a novel MDM2-p53-CDC20 signaling pathway in DLBCL have still remained unclear.Materials and methodsRT-qPCR was performed in MDM2 knocked down (KD) and control (Ctrl) OCI-Ly3/OCI-Ly10 cells to investigate whether CDC20 was a downstream gene of the MDM2-p53 pathway. The effects of CDC20 on cell proliferation, cell cycle and apoptosis were assessed, as well as the role of CDC20 in suppressing tumorigenicity in vivo. Furthermore, we also investigated the roles of CDC20 and MDM2 in progression of DLBCL and the underlying mechanisms.ResultsThe results of RT-qPCR revealed that CDC20 was downregulated while TP53 was upregulated in MDM2 KD OCI-Ly3 and OCI-Ly10 cells. It was unveiled that the expression levels of CDC20 and MDM2 were upregulated in DLBCL tissues and cells, and high CDC20 expression was correlated with adverse clinical features and poor outcome. Functional assays showed that downregulation of CDC20 could inhibit proliferation, induce apoptosis and cell cycle arrest in vitro. In addition, inactivation of the MDM2-p53 pathway by downregulation of MDM2 restored wtp53 expression level and reduced CDC20 protein level in OCI-Ly3 and OCI-Ly10 cells. Besides, targeting CDC20 was found to suppress tumorigenesis of DLBCL in vivo.ConclusionCDC20 was identified as a key downstream gene of the MDM2-p53 signaling pathway in DLBCL and may be used as a novel target gene to guide therapeutic applications.
| S-EPMC7575066 | biostudies-literature
Project description:Objectivep53 gene, as "the guardian of the genome", is the most widely studied tumor suppressor gene. Previous studies have shown that about 50 percent of tumors have P53 dysfunction. This article aims to retrospectively analyze the correlation between p53 rs1625895 polymorphism and the prognosis of patients with diffuse large B-cell lymphoma (DLBCL).MethodsPCR combined with Sanger sequencing were used to detect rs1625895 genotype in 384 DLBCL patients. The relationship between rs1625895 polymorphisms and the clinical characteristics, first-line therapeutic effects and the prognosis of the patients were analyzed.ResultsAmong all the patients, 2 (0.5%) patients with AA genotype, 34 (8.9%) patients with AG genotype and 348 (90.6%) patients with GG genotype were identified. The patients with different rs1625895 genotypes did not have any difference in terms of age, gender, B symptoms (developing any of the following symptoms: unexplained recurrent fever (often above 38 °C), night sweats, and unexplained weight loss of 10% within 6 months ), erythrocyte sedimentation rate (ESR), international prognostic index (IPI) and molecular subtype (P>0.05). The overall response rate (ORR) was 82.9% and 82.8% in AA/AG and GG, respectively. There was no significant difference between the first-line therapeutic effects of the two groups (P>0.05). And there was also no difference between A allele carriers and homozygous G allele carriers for the 5-year progressionfree survival rate (PFS) (71.8% vs. 62.3%, χ2=1.351, P=0.245) and 5-year overall survival rate (OS) (72.2% vs. 64.1%, χ2=1.267, P=0.260). But in the subgroup with Germinal Center B-cell (GCB) type, the patients carrying A allele for rs1625895 had an obviously longer PFS (91.7% vs. 72.7%, χ2=4.493, P=0.034) and OS (91.7% vs. 76.7%, χ2=4.246, P=0.039) compared with the patients homozygous for the G allele. As for the patients with non-GCB subtype, there was no significant difference in PFS and OS between different rs1625895 genotypes (P>0.05). According to whether the first-line regimen contained rituximab or not, the patients were divided into two groups treated with cyclophosphoramide, doxorubicin, vincristine and prednisone (CHOP) or with rituximab and CHOP (R-CHOP). But in both subgroups, there was no significant difference in the 5-year PFS and OS between the AA/AG and GG patients, too (P>0.05).ConclusionFor DLBCL patients receiving CHOP regimen chemotherapy in the first line, p53 rs1625895 cannot predict the clinical efficacy and prognosis of the patients, but in the patients with GCB subtype, this polymorphism may be a prognostic indicator.
| S-EPMC7433513 | biostudies-literature
Project description:The prognostic implications of miR-21, miR-17-92 and miR-155 were evaluated in diffuse large B-cell lymphoma (DLBCL) patients, and novel mechanism by which miR-21 contributes to the oncogenesis of DLBCL by regulating FOXO1 and PI3K/AKT/mTOR pathway was investigated. The expressions of miR-21, miR-17-92 and miR-155 measured by quantitative reverse-transcription-PCR were significantly up-regulated in DLBCL tissues (n=200) compared to control tonsils (P=0.012, P=0.001 and P<0.0001). Overexpression of miR-21 and miR-17-92 was significantly associated with shorter progression-free survival (P=0.003 and P=0.014) and overall survival (P=0.004 and P=0.012). High miR-21 was an independent prognostic factor in DLBCL patients treated with rituximab-combined chemotherapy. MiR-21 level was inversely correlated with the levels of FOXO1 and PTEN in DLBCL cell lines. Reporter-gene assay showed that miR-21 directly targeted and suppressed the FOXO1 expression, and subsequently inhibited Bim transcription in DLBCL cells. MiR-21 also down-regulated PTEN expression and consequently activated the PI3K/AKT/mTOR pathway, which further decreased FOXO1 expression. Moreover, miR-21 inhibitor suppressed the expression and activity of MDR1, thereby sensitizing DLBCL cells to doxorubicin. These data demonstrated that miR-21 plays an important oncogenic role in DLBCL by modulating the PI3K/AKT/mTOR/FOXO1 pathway at multiple levels resulting in strong prognostic implication. Therefore, targeting miR-21 may have therapeutic relevance in DLBCL.
| S-EPMC4558134 | biostudies-literature
Project description: Not available
| S-EPMC8377611 | biostudies-literature
Project description:Abnormalities in the TP53 gene and overexpression of MDM2, a transcriptional target and negative regulator of p53, are commonly observed in cancers. The MDM2-p53 feedback loop plays an important role in tumor progression and thus, increased understanding of the pathway has the potential to improve clinical outcomes for cancer patients. Hepatocellular carcinoma (HCC) has emerged as one of the most commonly diagnosed forms of human cancer; yet, the current treatment for HCC is less effective than those used against other cancers. We review the current studies of the MDM2-p53 pathway in cancer with a focus on HCC and specifically discuss the impact of p53 mutations along with other alterations of the MDM2-p53 feedback loop in HCC. We also discuss the potential diagnostic and prognostic applications of p53 and MDM2 in malignant tumors as well as therapeutic avenues that are being developed to target the MDM2-p53 pathway.
| S-EPMC4504428 | biostudies-literature
Project description:The p53 signalling pathway, which controls cell fate, has been extensively studied due to its prominent role in tumor development. The pathway includes the tumor supressor protein p53, its vertebrate paralogs p63 and p73, and their negative regulators MDM2 and MDM4. The p53/p63/p73-MDM system is ancient and can be traced in all extant animal phyla. Despite this, correct phylogenetic trees including both vertebrate and invertebrate species of the p53/p63/p73 and MDM families have not been published.Here, we have examined the evolution of the p53/p63/p73 protein family with particular focus on the p53/p63/p73 transactivation domain (TAD) and its co-evolution with the p53/p63/p73-binding domain (p53/p63/p73BD) of MDM2. We found that the TAD and p53/p63/p73BD share a strong evolutionary connection. If one of the domains of the protein is lost in a phylum, then it seems very likely to be followed by loss of function by the other domain as well, and due to the loss of function it is likely to eventually disappear. By focusing our phylogenetic analysis to p53/p63/p73 and MDM proteins from phyla that retain the interaction domains TAD and p53/p63/p73BD, we built phylogenetic trees of p53/p63/p73 and MDM based on both vertebrate and invertebrate species. The trees follow species evolution and contain a total number of 183 and 98 species for p53/p63/p73 and MDM, respectively. We also demonstrate that the p53/p63/p73 and MDM families result from whole genome duplications.The signaling pathway of the TAD and p53/p63/p73BD in p53/p63/p73 and MDM, respectively, dates back to early metazoan time and has since then tightly co-evolved, or disappeared in distinct lineages.
| S-EPMC5543598 | biostudies-literature
Project description:BackgroundThe aggressive B-cell non-Hodgkin lymphomas diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) are characterised by a high proliferation rate. The anaphase-promoting complex/cyclosome (APC/C) and its co-activators Cdc20 and Cdh1 represent an important checkpoint in mitosis. Here, the role of the APC/C and its co-activators is examined in DLBCL and MCL.MethodsThe expression and prognostic value of Cdc20 and Cdh1 was investigated using GEP data and immunohistochemistry. Moreover, the therapeutic potential of APC/C targeting was evaluated using the small-molecule inhibitor proTAME and the underlying mechanisms of action were investigated by western blot.ResultsWe demonstrated that Cdc20 is highly expressed in DLBCL and aggressive MCL, correlating with a poor prognosis in DLBCL. ProTAME induced a prolonged metaphase, resulting in accumulation of the APC/C-Cdc20 substrate cyclin B1, inactivation/degradation of Bcl-2 and Bcl-xL and caspase-dependent apoptosis. In addition, proTAME strongly enhanced the anti-lymphoma effect of the clinically relevant agents doxorubicin and venetoclax.ConclusionWe identified for the first time APC/C as a new, promising target in DLBCL and MCL. Moreover, we provide evidence that Cdc20 might be a novel, independent prognostic factor in DLBCL and MCL.
| S-EPMC6738099 | biostudies-literature
Project description:The BCL6 proto-oncogene encodes a transcriptional repressor that is required for germinal center (GC) formation and whose deregulation by genomic lesions is implicated in the pathogenesis of GC-derived diffuse large B cell lymphoma (DLBCL) and, less frequently, follicular lymphoma (FL). The biological function of BCL6 is only partially understood because no more than a few genes have been functionally characterized as direct targets of BCL6 transrepression activity. Here we report that the anti-apoptotic proto-oncogene BCL2 is a direct target of BCL6 in GC B cells. BCL6 binds to the BCL2 promoter region by interacting with the transcriptional activator Miz1 and suppresses Miz1-induced activation of BCL2 expression. BCL6-mediated suppression of BCL2 is lost in FL and DLBCL, where the 2 proteins are pathologically coexpressed, because of BCL2 chromosomal translocations and other mechanisms, including Miz1 deregulation and somatic mutations in the BCL2 promoter region. These results identify an important function for BCL6 in facilitating apoptosis of GC B cells via suppression of BCL2, and suggest that blocking this pathway is critical for lymphomagenesis.
| S-EPMC2708681 | biostudies-literature
Project description:BackgroundSNP309 T/G (rs2279744) causes higher levels of MDM2, the most important negative regulator of the p53 tumor suppressor. SNP72 G/C (rs1042522) gives rise to a p53 protein with a greatly reduced capacity to induce apoptosis. Both polymorphisms have been implicated in cancer. The SNP309 G-allele has recently been reported to accelerate diffuse large B-cell lymphoma (DLBCL) formation in pre-menopausal women and suggested to constitute a genetic basis for estrogen affecting human tumorigenesis. Here we asked whether SNP309 and SNP72 are associated with DLBCL in women and are correlated with age of onset, diagnosis, or patient's survival.MethodsSNP309 and SNP72 were PCR-genotyped in a case-control study that included 512 controls and 311 patients diagnosed with aggressive NHL. Of these, 205 were diagnosed with DLBCL.ResultsThe age of onset was similar in men and women. The control and patients group showed similar SNP309 and SNP72 genotype frequencies. Importantly and in contrast to the previous findings, similar genotype frequencies were observed in female patients diagnosed by 51 years of age and those diagnosed later. Specifically, 3/20 female DLBCL patients diagnosed by 51 years of age were homozygous for SNP309 G and 2/20 DLBCL females in that age group were homozygous for SNP72 C. Neither SNP309 nor SNP72 had a significant influence on event-free and overall survival in multivariate analyses.ConclusionIn contrast to the previous study on Ashkenazi Jewish Caucasians, DLBCL in pre-menopausal women of central European Caucasian ethnicity was not associated with SNP309 G. Neither SNP309 nor SNP72 seem to be correlated with age of onset, diagnosis, or survival of patients.
| S-EPMC2375899 | biostudies-literature
Project description:Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically heterogeneous: 40% of patients respond well to current therapy and have prolonged survival, whereas the remainder succumb to the disease. We proposed that this variability in natural history reflects unrecognized molecular heterogeneity in the tumors. Using DNA microarrays, we have conducted a systematic characterization of gene expression in B-cell malignancies. Here we show that there is diversity in gene expression among the tumors of DLBCL patients, apparently reflecting the variation in tumor proliferation rate, host response and differentiation state of the tumor. We identified two molecularly distinct forms of DLBCL which had gene expression patterns indicative of different stages of B-cell differentiation. One type expressed genes characteristic of germinal center B cells ('germinal center B-like DLBCL'); the second type expressed genes normally induced during in vitro activation of peripheral blood B cells ('activated B-like DLBCL'). Patients with germinal center B-like DLBCL had a significantly better overall survival than those with activated B-like DLBCL. The molecular classification of tumors on the basis of gene expression can thus identify previously undetected and clinically significant subtypes of cancer. This study is described more fully in Alizadeh AA et al.(2000) Nature 403:503-11 Keywords: other
2002-06-27 | GSE60 | GEO