Reciprocal negative regulation between the tumor suppressor protein p53 and B cell CLL/lymphoma 6 (BCL6) via control of caspase-1 expression

Effect of caspase-1 (CASP1) combined with multimodal ultrasound features on the prognosis of breast cancer patients

Background

Breast cancer (BRCA) is the malignant tumor with the highest incidence rate among women in the world, and its mortality rate ranks second. The purpose of our study is to explore the correlation between caspase-1 (CASP1) and the prognosis of BRCA patients and the potential mechanism of action, and to analyze the clinical value of CASP1 combined with multimodal ultrasound features in early screening and prognosis of BRCA.

Methods

We analyzed The Cancer Genome Atlas (TCGA) database to confirm that CASP1 was expressed in BRCA patients and determine whether its expression was correlated with patient prognosis. The relationship between CASP1 expression and survival was measured by the clinicopathological parameters. Multivariate analysis was performed using Cox regression, and a nomogram was developed using these results for quality assurance purposes. The correlations between CASP1 and immune cells were investigated using the Tumor Immune Estimation Resource (TIMER) and TCGA databases. Next, we performed gene set enrichment analysis (GSEA) to determine the potential mechanism of action. Finally, to analyze the effect of CASP1 combined with multimodal ultrasonography characteristics on the prognosis of BRCA patients was studied by analyzing the clinical data of patients.

Results

CASP1 expression was lower in BRCA tumor tissues than in the surrounding tissues. Patients with high CASP1 expression had better overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) than those with low CASP1 expression. GSEA suggested that CASP1 may affect the cell cycle, immune environment, inflammation, apoptosis, the HIPPOMERLIN pathway, Natural killer (NK) cell regulation of cytotoxicity, p53 expression, the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, the mitogen-activated protein kinase (MAPK) pathway, extracellular matrix, etc., thereby influencing the biological events in BRCA. Among conventional ultrasound features and contrast-enhanced ultrasound (CEUS) features, mass margin status and blood flow grade were associated with the expression of CASP1. Meanwhile, patients with poor ultrasound features tended to have low CASP1 expression.

Conclusions

CASP1 may be a novel predictive marker for BRCA patients. CASP1 combined with multimodal ultrasound features has good clinical value in the early screening and prognostic prediction of BRCA.

Post-translational regulation of proto-oncogene ZBTB7A expression by p53 status in cancer cells: HSP90-dependent stabilization vs. p53-KLHL20-ubiquitin proteasomal degradation

ZBTB7A overexpressed in many human cancers is a major oncogenic driver. ZBTB7A promotes tumorigenesis by regulating transcription of the genes involved in cell survival and proliferation, apoptosis, invasion, and migration/metastasis. One unresolved issue is the mechanism underlying the aberrant overexpression of ZBTB7A in cancer cells. Interestingly, inhibition of HSP90 decreased ZBTB7A expression in a variety of human cancer cells. ZBTB7A interacts with and is stabilized by HSP90. Inhibition of HSP90 by 17-AAG resulted in p53-dependent proteolysis of ZBTB7A via increased p53 expression and upregulation of the CUL3-dependent E3 ubiquitin ligase, KLHL20. Down-regulation of ZBTB7A resulted in the derepression of a major negative regulator of cell cycle progression, p21/CDKN1A. We discovered a new function of p53 regulating ZBTB7A expression through KLHL20-E3 ligase and proteasomal protein degradation system.

A pyroptosis-related signature predicts prognosis and indicates immune microenvironment infiltration in glioma

BACKGROUND

Glioma, the most common malignant brain tumor, leads to high recurrence rates and disabilities in patients. Pyroptosis is an inflammasomes-induced programmed cell death in response to infection or chemotherapy. However, the role of pyroptosis in glioma has not yet been elucidated.

METHODS

RNA-seq data and clinical information of 660 gliomas and 847 samples were downloaded from the TCGA and CGGA, respectively. Then, data of 104 normal brain tissues was retrieved from the GTEx for differential expression analysis. Twelve pairs of peritumoral tissue and glioma samples were used for validation. Gene alteration status of differentially expressed pyroptosis-related regulators in gliomas was detected in cBioPortal algorithm. Consensus clustering was employed to classify gliomas based on differentially expressed pyroptosis-related regulators. Subsequently, a PS-signature was constructed using LASSO-congressional analysis for clinical application. The immune infiltration of glioma microenvironment (TME) was explored using ESTIMATE, CIBERSORT, and the other immune signatures.

RESULTS

cBioPortal algorithm revealed alteration of these regulators was correlated to better prognosis of gliomas. Then, our study showed that pyroptosis-related regulators can be used to sort out patients into two clusters with distinct prognostic outcome and immune status. Moreover, a PS-signature for predicting the prognosis of glioma patients was developed based on the identified subtypes. The high PS-score group showed more abundant inflammatory cell infiltration and stronger immune response, but with poorer prognosis of gliomas.

CONCLUSION

The findings of this study provide a therapeutic basis for future research on pyroptosis and unravel the relationship between pyroptosis and glioma prognosis. The risk signature can be utilized as a prognostic biomarker for glioma.

DSF/Cu induces antitumor effect against diffuse large B-cell lymphoma through suppressing NF-κB/BCL6 pathways

Background

The B-cell lymphoma 6 (BCL6) oncogene is required for the survival of diffuse large B-cell lymphoma (DLBCL), which is incurable using conventional chemotherapy. Thus, it is imperative to improve the survival of patients with DLBCL. Disulfide (DSF) has been shown to have anticancer effects, but its effect on DLBCL remains unclear.

Methods

Four DLBCL cell lines (OCI-LY1, OCI-LY7, OCI-LY10 and U2932) and primary DLBCL cells from eight newly diagnosed DLBCL patients were pretreated with DSF alone or in combination with Cu. Cell morphology was observed under microscope. Flow cytometry was performed to evaluate the cell apoptosis, cell cycle, the mitochondrial membrane potential and the intracellular accumulation of reactive oxygen species (ROS). The protein expression was respectively measured by flow cytometry and western blotting.

Results

DSF or DSF/Cu exhibited a marked inhibitory effect on the growth of DLBCL cells, accompanied by cell cycle arrest at the G0/G1 phase. Meanwhile, DSF or DSF/Cu significantly induced DLBCL cells apoptosis. Further study revealed that DSF or DSF/Cu promoted apoptosis by inhibiting NF-κB signaling pathway. Interestingly, DSF/Cu significantly reduced BCL6 and AIP levels. In addition, DSF significantly up-regulate p53 protein in OCI-LY7 and OCI-LY10 while down-regulate p53 protein in OCI-LY1 and U2932.

Conclusion

These results provided evidence for the anti-lymphoma effects of DSF on DLBCL and suggested that DSF has therapeutic potential to DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02661-4.

Low BACH2 Expression Predicts Adverse Outcome in Chronic Lymphocytic Leukaemia

Chronic lymphocytic leukaemia (CLL) is a heterogeneous disease with a highly variable clinical outcome. There are well-established CLL prognostic biomarkers that have transformed treatment and improved the understanding of CLL biology. Here, we have studied the clinical significance of two crucial B cell regulators, BACH2 (BTB and CNC homology 1, basic leucine zipper transcription factor 2) and BCL6 (B-cell CLL/lymphoma 6), in a cohort of 102 CLL patients and determined the protein interaction networks that they participate in using MEC-1 CLL cells. We observed that CLL patients expressing low levels of BCL6 and BACH2 RNA had significantly shorter overall survival (OS) than high BCL6- and BACH2-expressing cases. Notably, their low expression specifically decreased the OS of immunoglobulin heavy chain variable region-mutated (IGHV-M) CLL patients, as well as those with 11q and 13q deletions. Similar to the RNA data, a low BACH2 protein expression was associated with a significantly shorter OS than a high expression. There was no direct interaction observed between BACH2 and BCL6 in MEC-1 CLL cells, but they shared protein networks that included fifty different proteins. Interestingly, a prognostic index (PI) model that we generated, using integrative risk score values of BACH2 RNA expression, age, and 17p deletion status, predicted patient outcomes in our cohort. Taken together, these data have shown for the first time a possible prognostic role for BACH2 in CLL and have revealed protein interaction networks shared by BCL6 and BACH2, indicating a significant role for BACH2 and BCL6 in key cellular processes, including ubiquitination mediated B-cell receptor functions, nucleic acid metabolism, protein degradation, and homeostasis in CLL biology.

Epstein Barr virus-positive B-cell lymphoma is highly vulnerable to MDM2 inhibitors in vivo

MDM2 inhibitors have potent in vivo activity against and could be a novel therapy for EBV-positive B-cell lymphoma.

EBV positivity or loss of BCL6 expression can be a potential predictive biomarker for response to MDM2 inhibitors in patients with lymphoma

Epstein-Barr virus–positive (EBV-positive) B-cell lymphomas are common in immunocompromised patients and remain an unmet medical need. Here we report that MDM2 inhibitors (MDM2is) navtemadlin and idasanutlin have potent in vivo activity in EBV-positive B-cell lymphoma established in immunocompromised mice. Tumor regression was observed in all 5 EBV-positive xenograft–associated B-cell lymphomas treated with navtemadlin or idasanutlin. Molecular characterization showed that treatment with MDM2is resulted in activation of p53 pathways and downregulation of cell cycle effectors in human lymphoma cell lines that were either EBV-positive or had undetectable expression of BCL6, a transcriptional inhibitor of the TP53 gene. Moreover, treatment with navtemadlin resulted in tumor regression and prevented systemic dissemination of EBV-positive lymphoma derived from 2 juvenile patients with posttransplant lymphoproliferative diseases, including 1 whose tumor was resistant to virus-specific T-cell therapy. These results provide proof-of-concept for targeted therapy of EBV-positive lymphoma with MDM2is and the feasibility of using EBV infection or loss of BCL6 expression to identify responders to MDM2is.

The Mechanism of Nano-Particles Intervening Invasion and Metastasis of Lymphoma Based on Autophagy Targeted with miR-36b and Orienteering Analysis on Apoptosis Gene

Whether the expression of gene P53 related with autophagy and apoptosis and action was regulated by miR-36b was discussed in our study. And the action of orienteering nano-particles on intervening invasion and metastasis of lymphoma was analyzed. The normal lymphoid tissue collected from the patients with simple lymphatic hyperplasia was set as control. The lymphoma samples from patients with early indolent lymphoma were collected. The level of mRNA in miR-36b and P53 was detected by PCR. The level of P53 protein and level of mRNA in miR-36b and P53 among normal lymphoid cell, cell strain of low metastatic lymphoma and cell strain of high metastatic lymphoma was compared. They were divided into four groups: miR-NC group, orienteering nano-particles’ group, siRNA-NC group and siRNA-P53 group. The cell proliferative capacity was detected by FCM. The quantity of cell invasion and metastasis was detected by transwell. The expression quantity of P53 mRNA in lymphoma tissue was increased obviously compared with control group. The expression of miR-36b was lower while the expression of P53 was higher along with the later staging of TNM. And the express was related with the staging of TNM. The expression quantity of P53 mRNA in lymphoma cell was higher in normal cell notably. But expression quantity of miR-36b in lymphoma cell was lower in normal cell notably. The decreased of expression of miR-36b and increased of expression of P53 was related with enhancing the ability of invasion and metastasis of lymphoma cells.

Expression and prognosis analyses of CASP1 in acute myeloid leukemia

Caspase1 (CASP1) is a gene that encodes multiple proteins related to cell death. Nevertheless, the function of CASP1 in the pathogenesis of AML is still unclear. In the present study, a detailed analysis of cancer versus normal samples was performed to explore the relationship between CASP1 and leukemia. We used sequencing data from multiple cancer gene databases to analyze the gene expression and regulatory network of CASP1 in leukemia. We discovered that mRNA expression levels of CASP1 are increased in leukemia cell lines, especially in acute myelocytic leukemia (AML). Then, we verified the mRNA expression of CASP1 in AML clinical samples and observed significantly higher expression of CASP1 in relapsed AML patients. High CASP1 expression was associated with poor prognosis and CASP1 inhibition could impair the proliferation of AML cells. Related functional network identification suggests that CASP1 regulates apoptosis, immune and inflammatory response via pathways involving LYN, LCK, and the E2F family. These findings suggest that CASP1 probably contributes to the pathogenesis, and identify CASP1 as a factor for predicting the prognosis and as a therapeutic target of AML patients.

KLHL4, a novel p53 target gene, inhibits cell proliferation by activating p21WAF/CDKN1A

KLHL4 is a member of the KLHL protein family, many of whom bind the Cul3 E3 ligase, and mediate the ubiquitination of interacting proteins. The KLHL4 gene, localized on the X chromosome, associates with a disorder known as X-linked cleft palate (CPX). However, the biological functions of KLHL4 are largely unknown. In this study, microarray analysis of HEK293A embryonic kidney cells, expressing ectopic p53, showed a 3-fold increase of KLHL4 mRNA. Moreover, both KLHL4 mRNA and protein expression were elevated by p53 or DNA damage, suggesting that KLHL4 might be a p53 target gene. We also found that KLHL4 activates transcription of p21^WAF/CDKN1A, a p53 target gene encoding a major negative regulator of the cell-cycle. KLHL4 interacted with p53 to increase its binding to p53 response element of the p21^WAF/CDKN1A gene, resulting in transcriptional upregulation. Furthermore, we observed that KLHL4 can interact with the Cul3 ubiquitin ligase, to possibly play a role in ubiquitin-mediated proteasomal degradation, and Klhl4 knocked-out MEF mouse embryonic fibroblasts proliferated faster than WT MEF cells. These results suggest that KLHL4 upregulation by p53 may inhibit cell proliferation, by activating p21^WAF/CDKN1A.

HIC2, a new transcription activator of SIRT1

The protein deacetylase SIRT1 is crucial to numerous physiological processes, such as aging, metabolism, and autoimmunity, and is repressed by various transcription factors, including HIC1. Conversely, we found that HIC2, which is highly homologous to HIC1, is a transcriptional activator of SIRT1 due to opposite activity of the intermediate domains of the two homologs. Importantly, this relationship between HIC2 and SIRT1 could be important for cardiac development, where both proteins are implicated. Here, we assessed whether ectopic expression of HIC2, and subsequent upregulation of SIRT1, might decrease apoptosis in H9c2 cardiomyocytes under simulated ischemia/reperfusion (I/R) injury conditions. Our results demonstrate that unlike its structural homolog HIC1, HIC2 is a pivotal transcriptional activator of SIRT1 and, consequently, may protect the heart from I/R injury.

Single-Cell RNA-Sequencing Identifies Activation of TP53 and STAT1 Pathways in Human T Lymphocyte Subpopulations in Response to Ex Vivo Radiation Exposure

Detrimental health consequences from exposure to space radiation are a major concern for long-duration human exploration missions to the Moon or Mars. Cellular responses to radiation are expected to be heterogeneous for space radiation exposure, where only high-energy protons and other particles traverse a fraction of the cells. Therefore, assessing DNA damage and DNA damage response in individual cells is crucial in understanding the mechanisms by which cells respond to different particle types and energies in space. In this project, we identified a cell-specific signature for radiation response by using single-cell transcriptomics of human lymphocyte subpopulations. We investigated gene expression in individual human T lymphocytes 3 h after ex vivo exposure to 2-Gy gamma rays while using the single-cell sequencing technique (10X Genomics). In the process, RNA was isolated from ~700 irradiated and ~700 non-irradiated control cells, and then sequenced with ~50 k reads/cell. RNA in each of the cells was distinctively barcoded prior to extraction to allow for quantification for individual cells. Principal component and clustering analysis of the unique molecular identifier (UMI) counts classified the cells into three groups or sub-types, which correspond to CD4+, naïve, and CD8+/NK cells. Gene expression changes after radiation exposure were evaluated using negative binomial regression. On average, BBC3, PCNA, and other TP53 related genes that are known to respond to radiation in human T cells showed increased activation. While most of the TP53 responsive genes were upregulated in all groups of cells, the expressions of IRF1, STAT1, and BATF were only upregulated in the CD4+ and naïve groups, but were unchanged in the CD8+/NK group, which suggests that the interferon-gamma pathway does not respond to radiation in CD8+/NK cells. Thus, single-cell RNA sequencing technique was useful for simultaneously identifying the expression of a set of genes in individual cells and T lymphocyte subpopulation after gamma radiation exposure. The degree of dependence of UMI counts between pairs of upregulated genes was also evaluated to construct a similarity matrix for cluster analysis. The cluster analysis identified a group of TP53-responsive genes and a group of genes that are involved in the interferon gamma pathway, which demonstrate the potential of this method for identifying previously unknown groups of genes with similar expression patterns.