Serum/glucocorticoid-regulated kinase 1 contributes to the proliferation of varicella-zoster virus and induction of cyclin B1 expression.

In this study, we investigated the role of serum/glucocorticoid-regulated kinase 1 (SGK1) in varicella-zoster virus (VZV) replication. VZV DNA replication and plaque formation were inhibited by SGK1 knockout and treatment with an SGK1 inhibitor. Furthermore, SGK1 inhibition suppressed the increase in cyclin B1 expression induced by VZV infection. These results suggest that VZV infection induces SGK1 activation, which is required for efficient viral proliferation through the expression of cyclin B1. This is the first study to report that SGK1 is involved in the VZV life cycle.

KIF22 promotes multiple myeloma progression by regulating the CDC25C/CDK1/cyclinB1 pathway.

PURPOSE: Multiple myeloma (MM) is an incurable hematological malignancy characterized by clonal proliferation of malignant plasma B cells in bone marrow, and its pathogenesis remains unknown. The aim of this study was to determine the role of kinesin family member 22 (KIF22) in MM and elucidate its molecular mechanism. METHODS: The expression of KIF22 was detected in MM patients based upon the public datasets and clinical samples. Then, in vitro assays were performed to investigate the biological function of KIF22 in MM cell lines, and subcutaneous xenograft models in nude mice were conducted in vivo. Chromatin immunoprecipitation (ChIP) and luciferase reporter assay were used to determine the mechanism of KIF22-mediated regulation. RESULTS: The results demonstrated that the expression of KIF22 in MM patients was associated with several clinical features, including gender (P = 0.016), LDH (P < 0.001), ß2-MG (P = 0.003), percentage of tumor cells (BM) (P = 0.002) and poor prognosis (P < 0.0001). Furthermore, changing the expression of KIF22 mainly influenced the cell proliferation in vitro and tumor growth in vivo, and caused G2/M phase cell cycle dysfunction. Mechanically, KIF22 directly transcriptionally regulated cell division cycle 25C (CDC25C) by binding its promoter and indirectly influenced CDC25C expression by regulating the ERK pathway. KIF22 also regulated CDC25C/CDK1/cyclinB1 pathway. CONCLUSION: KIF22 could promote cell proliferation and cell cycle progression by transcriptionally regulating CDC25C and its downstream CDC25C/CDK1/cyclinB1 pathway to facilitate MM progression, which might be a potential therapeutic target in MM.

[Identification of key genes in Wilms tumor based on high-throughput RNA sequencing and their impacts on prognosis and immune responses].

OBJECTIVE: To identify the key genes differentially expressed in Wilms tumor and analyze their potential impacts on prognosis and immune responses of the patients. METHODS: High-throughput RNA sequencing was used to identify the differentially expressed mRNAs in clinical samples of Wilms tumor and paired normal tissues, and their biological functions were analyzed using GO, KEGG and GSEA enrichment analyses. The hub genes were identified using STRING database, based on which a prognostic model was constructed using LASSO regression. The mutations of the key hub genes were analyzed and their impacts on immunotherapy efficacy was predicted using the cBioPortal platform. RT-qPCR was used to verify the differential expressions of the key hub genes in Wilms tumor. RESULTS: Of the 1612 differentially expressed genes identified in Wilms tumor, 1030 were up-regulated and 582 were down-regulated, involving mainly cell cycle processes and immune responses. Ten hub genes were identified, among which 4 genes (TP53, MED1, CCNB1 and EGF) were closely related to the survival of children with Wilms tumor. A 3-gene prognostic signature was constructed through LASSO regression analysis, and the patients stratified into with high- and low-risk groups based on this signature had significantly different survival outcomes (HR=1.814, log-rank P=0.002). The AUCs of the 3-, 5- and 7-year survival ROC curves of this model were all greater than 0.7. The overall mutations in the key hub genes or the individual mutations in TP53/CCNB1 were strongly correlated with a lower survival rates, and a high TP53 expression was correlated with a poor immunotherapy efficacy. RT-qPCR confirmed that the key hub genes had significant differential expressions in Wilms tumor tissues and cells. CONCLUSION: TP53 gene plays an important role in the Wilms tumor and may potentially serve as a new immunotherapeutic biomarker as well as a therapeutic target.

Regulatory Role of Meox1 in Muscle Growth of Sebastes schlegelii.

Meox1 is a critical transcription factor that plays a pivotal role in embryogenesis and muscle development. It has been established as a marker gene for growth-specific muscle stem cells in zebrafish. In this study, we identified the SsMeox1 gene in a large teleost fish, Sebastes schlegelii. Through in situ hybridization and histological analysis, we discovered that SsMeox1 can be employed as a specific marker of growth-specific muscle stem cells, which originate from the somite stage and are primarily situated in the external cell layer (ECL) and myosepta, with a minor population distributed among muscle fibers. The knockdown of SsMeox1 resulted in a significant increase in Ccnb1 expression, subsequently promoting cell cycle progression and potentially accelerating the depletion of the stem cell pool, which ultimately led to significant growth retardation. These findings suggest that SsMeox1 arrests the cell cycle of growth-specific muscle stem cells in the G2 phase by suppressing Ccnb1 expression, which is essential for maintaining the stability of the growth-specific muscle stem cell pool. Our study provides significant insights into the molecular mechanisms underlying the indeterminate growth of large teleosts.

Effects of silencing NLRP3 gene on proliferation of psoriasis-like HaCaT cells and expressions of cytokines.

We aimed to explore the effects of silencing NOD-like receptor protein 3 (NLRP3) on proliferation of psoriasis-like HaCaT cells and expressions of cytokines. HaCaT cells were treated with human keratinocyte growth factor (KGF) and were divided into KGF group, negative control group, NLRP3-RNAi group and control group. Cells proliferation was detected by CCK8, cell clone formation rate was detected by clone formation assay, distribution of cells cycle was detected by flow cytometry, expressions of cyclin B1 (Cyclin B1), cyclin-dependent kinase 2 (CDK2), Ki67 and proliferating cell nuclear antigen (PCNA) proteins were detected by Western blot, and levels of interleukin (IL)-17, IL-23, IL-6 and tumor necrosis factor α (TNF-α) were detected by enzyme-linked immunosorbent assay. Compared with control group, expressions of NLRP3 mRNA and protein, proliferation rate and clonal formation rate were increased in KGF group, percentage of cells in G0/G1 phase was decreased, percentage of cells in S phase was increased, expressions of Cyclin B1, CDK2, Ki67 and PCNA proteins were increased, and levels of IL-17, IL-23, IL-6 and TNF-α were increased. Compared with negative control group, expressions of NLRP3 mRNA and protein, proliferation rate and clonal formation rate were decreased in NLRP3-RNAi group, percentage of cells in G0/G1 phase was increased, percentage of cells in S phase was decreased, expressions of Cyclin B1, CDK2, Ki67 and PCNA proteins were decreased, and levels of IL-17, IL-23, IL-6 and TNF-α were decreased. Silencing NLRP3 gene can inhibit the proliferation of psoriasis-like HaCaT cells, arrest cell cycle, inhibit the expressions of cell proliferation-related proteins and reduce levels of pro-inflammatory factors.

Toxoplasma gondii modulates the host cell cycle, chromosome segregation, and cytokinesis irrespective of cell type or species origin.

BACKGROUND: Toxoplasma gondii is an apicomplexan intracellular obligate parasite and the etiological agent of toxoplasmosis in humans, domestic animals and wildlife, causing miscarriages and negatively impacting offspring. During its intracellular development, it relies on nutrients from the host cell, controlling several pathways and the cytoskeleton. T. gondii has been proven to control the host cell cycle, mitosis and cytokinesis, depending on the time of infection and the origin of the host cell. However, no data from parallel infection studies have been collected. Given that T. gondii can infect virtually any nucleated cell, including those of humans and animals, understanding the mechanism by which it infects or develops inside the host cell is essential for disease prevention. Therefore, we aimed here to reveal whether this modulation is dependent on a specific cell type or host cell species. METHODS: We used only primary cells from humans and bovines at a maximum of four passages to ensure that all cells were counted with appropriate cell cycle checkpoint control. The cell cycle progression was analysed using fluorescence-activated cell sorting (FACS)-based DNA quantification, and its regulation was followed by the quantification of cyclin B1 (mitosis checkpoint protein). The results demonstrated that all studied host cells except bovine colonic epithelial cells (BCEC) were arrested in the S-phase, and none of them were affected in cyclin B1 expression. Additionally, we used an immunofluorescence assay to track mitosis and cytokinesis in uninfected and T. gondii-infected cells. RESULTS: The results demonstrated that all studied host cell except bovine colonic epithelial cells (BCEC) were arrested in the S-phase, and none of them were affected in cyclin B1 expression. Our findings showed that the analysed cells developed chromosome segregation problems and failed to complete cytokinesis. Also, the number of centrosomes per mitotic pole was increased after infection in all cell types. Therefore, our data suggest that T. gondii modulates the host cell cycle, chromosome segregation and cytokinesis during infection or development regardless of the host cell origin or type.

Naringenin nanoparticles targeting cyclin B1 suppress the progression of rheumatoid arthritis-associated lung cancer by inhibiting fibroblast-to-myofibroblast transition.

There is growing evidence of an elevated risk of lung cancer in patients with rheumatoid arthritis. The poor prognosis of rheumatoid arthritis-associated lung cancer and the lack of therapeutic options pose an even greater challenge to the clinical management of patients. This study aimed to identify potential molecular targets associated with the progression of rheumatoid arthritis-associated lung cancer and examine the efficacy of naringenin nanoparticles targeting cyclin B1. Mendelian randomizatio analysis revealed that rheumatoid arthritis has a positive correlation with the risk of lung cancer. Cyclin B1 was significantly upregulated in patients with rheumatoid arthritis-associated lung cancer and was significantly overexpressed in synovial tissue fibroblasts. Furthermore, the overexpression of cyclin B1 in rheumatoid arthritis fibroblast-like synoviocytes, which promotes their proliferation and fibroblast-to-myofibroblast transition, can significantly contribute to the growth and infiltration of lung cancer cells. Importantly, our prepared naringenin nanoparticles targeting cyclin B1 effectively attenuated proliferation and fibroblast-to-myofibroblast transition by blocking cells at the G2/M phase. In vivo experiments, naringenin nanoparticles targeting cyclin B1 significantly alleviated the development of collagen-induced arthritis and lung orthotopic tumors. Collectively, our results reveal that naringenin nanoparticles targeting cyclin B1 can suppress the progression of rheumatoid arthritis-associated lung cancer by inhibiting fibroblast-to-myofibroblast transition. These findings provide new insights into the treatment of rheumatoid arthritis-associated lung cancer therapy.

Bioinformatics analysis highlights CCNB1 as a potential prognostic biomarker and an anti-kidney renal papillary cell carcinoma drug target.

Kidney renal papillary cell carcinoma (KIRP) is a common urinary tumor that causes lymph node invasion. Once metastatic, the prognosis is poor and there is a lack of effective early diagnostic markers for this tumor. The expression of CCNB1 in KIRP tumor tissues was significantly higher than that in normal tissues in The Cancer Genome Atlas database with or without the genotype-tissue expression database, and a consistent result was obtained in 32 paired tissues. In addition, CCNB1 expression increased remarkably with the progression of the T and M stages. Moreover, using the online HPA database, we verified that the immunohistochemical scores of CCNB1 in KIRP were higher than those in the normal kidney tissues. The higher expression group of CCNB1 showed a worse prognosis in KIRP. Moreover, the receiver operating characteristic curve, univariate and multivariate analyses, and construction of the column diagram further illustrated that CCNB1 was an independent prognostic factor for KIRP. Meanwhile, CCNB1 could better predict the 1- and 3-year survival rates of KIRP. Six genes were significantly and positively co-expressed with CCNB1. We also found that the CCNB1 high-expression group was enriched in the ECM_RECEPTOR_INTERACTION and FOCAL_ADHESION pathways. Finally, drug sensitivity analysis combined with molecular docking identified 5 targeting drugs with the strongest binding activity to CCNB1. CCNB1 is a potential and reliable biomarker for KIRP diagnosis and can be used to predict the survival of patients with KIRP. The 5 selected drugs targeting CCNB1 may provide new hopes for patients with KIRP metastasis.

Alternative cleavage and polyadenylation of the Ccnb1 mRNA defines accumulation of cyclin protein during the meiotic cell cycle.

Progression through the mitotic and meiotic cell cycle is driven by fluctuations in the levels of cyclins, the regulatory subunits controlling the localization and activity of CDK1 kinases. Cyclin levels are regulated through a precise balance of synthesis and degradation. Here we demonstrate that the synthesis of Cyclin B1 during the oocyte meiotic cell cycle is defined by the selective translation of mRNA variants generated through alternative cleavage and polyadenylation (APA). Using gene editing in mice, we introduced mutations into the proximal and distal polyadenylation elements of the 3' untranslated region (UTR) of the Ccnb1 mRNA. Through in vivo loss-of-function experiments, we demonstrate that the translation of mRNA with a short 3' UTR specifies Cyclin B1 protein levels that set the timing of meiotic re-entry. In contrast, translation directed by a long 3' UTR is necessary to direct Cyclin B1 protein accumulation during the MI/MII transition. These findings establish that the progression through the cell cycle is dependent on the selective translation of multiple mRNA variants generated by APA.

DEPDC1B enhances malignant phenotypes of multiple myeloma through upregulating CCNB1 and inhibiting p53 signaling pathway.

The identification and investigation of key molecules involved in the pathogenesis of multiple myeloma (MM) hold paramount clinical significance. This study primarily focuses on elucidating the role of DEPDC1B within the context of MM. Our findings robustly affirm the abundant expression of DEPDC1B in MM tissues and cell lines. Notably, DEPDC1B depletion exerted inhibitory effects on MM cell proliferation and migration while concurrently facilitating apoptosis and G2 cell cycle arrest. These outcomes stand in stark contrast to the consequences of DEPDC1B overexpression. Furthermore, we identified CCNB1 as a putative downstream target, characterized by a co-expression pattern with DEPDC1B, mediating DEPDC1B's regulatory influence on MM. Additionally, our results suggest that DEPDC1B knockdown may activate the p53 pathway, thereby impeding MM progression. To corroborate these in vitro findings, we conducted in vivo experiments that further validate the regulatory role of DEPDC1B in MM and its interaction with CCNB1 and the p53 pathway. Collectively, our research underscores DEPDC1B as a potent promoter in the development of MM, representing a promising therapeutic target for MM treatment. This discovery bears significant implications for future investigations in this field.

SETDB2 interacts with BUBR1 to induce accurate chromosome segregation independently of its histone methyltransferase activity.

SETDB2 is a H3K9 histone methyltransferase required for accurate chromosome segregation. Its H3K9 histone methyltransferase activity was reported to be associated with chromosomes during metaphase. Here, we confirm that SETDB2 is required for mitosis and accurate chromosome segregation. However, these functions are independent of its histone methyltransferase activity. Further analysis showed that SETDB2 can interact with BUBR1, and is required for CDC20 binding to BUBR1 and APC/C complex and CYCLIN B1 degradation. The ability of SETDB2 to regulate the binding of CDC20 to BUBR1 or APC/C complex, and stabilization of CYCLIN B1 are also independent of its histone methyltransferase activity. These results suggest that SETDB2 interacts with BUBR1 to promote binding of CDC20 to BUBR1 and APC3, then degrades CYCLIN B1 to ensure accurate chromosome segregation and mitosis, independently of its histone methyltransferase activity.

[Effects of Methionine Restriction on Proliferation, Cell Cycle, and Apoptosis of Human Acute Leukemia Cells].

OBJECTIVE: To investigate the effects of methionine restriction on proliferation, cell cycle and apoptosis of human acute leukemia cells. METHODS: Cell Counting Kit-8 (CCK-8) assay was used to detect the effect of methionine restriction on HL-60 and Jurkat cells proliferation. The effect of methionine restriction on cell cycle of HL-60 and Jurkat cells was examined by PI staining. Annexin V-FITC / PI double staining was applied to detect apoptosis of HL-60 and Jurkat cells following methionine restriction. The expression of cell cycle-related proteins cyclin B1, CDC2 and apoptosis-related protein Bcl-2 was evaluated by Western blot assay. RESULTS: Methionine restriction significantly inhibited the proliferation of HL-60 and Jurkat cells in a time-dependent manner (HL-60: r =0.7773, Jurkat: r =0.8725), arrested the cells at G2/M phase (P < 0.001), and significantly induced apoptosis of HL-60 and Jurkat cells (HL-60: P < 0.001; Jurkat: P < 0.05). Furthermore, Western blot analysis demonstrated that methionine restriction significantly reduced the proteins expression of Cyclin B1 (P < 0.05), CDC2 (P < 0.01) and Bcl-2 (P < 0.001) in HL-60 and Jurkat cells. CONCLUSION: Acute leukemia cells HL-60 and Jurkat exhibit methionine dependence. Methionine restriction can significantly inhibit the proliferation, promote cell cycle arrest and induce apoptosis of HL-60 and Jurkat cells, which suggests that methionine restriction may be a potential therapeutic strategy for acute leukemia.

KCNN1 promotes proliferation and metastasis of breast cancer via ERLIN2-mediated stabilization and K63-dependent ubiquitination of Cyclin B1.

Potassium Calcium-Activated Channel Subfamily N1 (KCNN1), an integral membrane protein, is thought to regulate neuronal excitability by contributing to the slow component of synaptic after hyperpolarization. However, the role of KCNN1 in tumorigenesis has been rarely reported, and the underlying molecular mechanism remains unclear. Here, we report that KCNN1 functions as an oncogene in promoting breast cancer cell proliferation and metastasis. KCNN1 was overexpressed in breast cancer tissues and cells. The pro-proliferative and pro-metastatic effects of KCNN1 were demonstrated by CCK8, clone formation, Edu assay, wound healing assay and transwell experiments. Transcriptomic analysis using KCNN1 overexpressing cells revealed that KCNN1 could regulate key signaling pathways affecting the survival of breast cancer cells. KCNN1 interacts with ERLIN2 and enhances the effect of ERLIN2 on Cyclin B1 stability. Overexpression of KCNN1 promoted the protein expression of Cyclin B1, enhanced its stability and promoted its K63 dependent ubiquitination, while knockdown of KCNN1 had the opposite effects on Cyclin B1. Knockdown (or overexpression) ERLNI2 partially restored Cyclin B1 stability and K63 dependent ubiquitination induced by overexpression (or knockdown) of KCNN1. Knockdown (or overexpression) ERLIN2 also partially neutralizes the effects of overexpression (or knockdown) KCNN1-induced breast cancer cell proliferation, migration and invasion. In paired breast cancer clinical samples, we found a positive expression correlations between KCNN1 and ERLIN2, KCNN1 and Cyclin B1, as well as ERLIN2 and Cyclin B1. In conclusion, this study reveals, for the first time, the role of KCNN1 in tumorigenesis and emphasizes the importance of KCNN1/ERLIN2/Cyclin B1 axis in the development and metastasis of breast cancer.

A pancancer analysis of the oncogenic role of cyclin B1 (CCNB1) in human tumors.

Aberrant levels of the G2/M cyclin cyclin B1 (gene CCNB1) have been associated with multiple cancers; however, the literature lacks a focused and comprehensive analysis of the regulation of this important regulator of cell proliferation in cancer. Through this work, we performed a pancancer analysis of the levels of CCNB1 and dissected aspects of regulation and how this correlates with cancer prognosis. We comprehensively evaluated the expression and promoter methylation of CCNB1 across 38 cancers based on RNA sequencing data obtained from the Cancer Genome Atlas (TCGA). The correlation of CCNB1 with prognosis and the tumor microenvironment was explored. Using lung adenocarcinoma data, we studied the potential upstream noncoding RNAs involved in the regulation of CCNB1 and validated the protein levels and prognostic value of CCNB1 for this disease site. CCNB1 was highly expressed, and promoter methylation was reduced in most cancers. Gene expression of CCNB1 correlated positively with poor prognosis of tumor patients, and these results were confirmed at the protein level using lung adenocarcinoma. CCNB1 expression was associated with the infiltration of T helper cells, and this further correlated with poor prognosis for certain cancers, including renal clear cell carcinoma and lung adenocarcinoma. Subsequently, we identified a specific upstream noncoding RNA contributing to CCNB1 overexpression in lung adenocarcinoma through correlation analysis, expression analysis and survival analysis. This study provides a comprehensive analysis of the expression and methylation status of CCNB1 across several forms of cancer and provides further insight into the mechanistic pathways regulating Cyclin B1 in the tumorigenesis process.

Tumor suppressor Parkin induces p53-mediated cell cycle arrest in human lung and colorectal cancer cells.

Dysregulation of the E3 ubiquitin ligase Parkin has been linked to various human cancers, indicating that Parkin is a tumor suppressor protein. However, the mechanisms of action of Parkin remain unclear to date. Thus, we aimed to elucidate the mechanisms of action of Parkin as a tumor suppressor in human lung and colorectal cancer cells. Results showed that Parkin overexpression reduced the viability of A549 human lung cancer cells by inducing G2/M cell cycle arrest. In addition, Parkin caused DNA damage and ATM (Ataxia telangiectasia mutated) activation, which subsequently led to p53 activation. It also induced the p53-mediated upregulation of p21 and downregulation of cyclin B1. Moreover, Parkin suppressed the proliferation of HCT-15 human colorectal cancer cells by a mechanism similar to that in A549 lung cancer cells. Taken together, our results suggest that the tumor-suppressive effects of Parkin on lung and colorectal cancer cells are mediated by DNA damage/p53 activation/cyclin B1 reduction/cell cycle arrest. [BMB Reports 2023; 56(10): 557-562].

MicroRNA-30c-5p arrests bladder cancer G2/M phase and suppresses its progression by targeting PRC1-mediated blocking of CDK1/Cyclin B1 axis.

BACKGROUND: MicroRNAs (miRNAs) play a critical role in cancer development and progression, the dis-regulation of miR-30c-5p has been observed in various malignant tumors but no research was done in bladder cancer (BCa). This study aims to investigate the downregulation of miR-30c-5p in BCa, and examine its mechanism and prognostic significance. METHODS: Bioinformatics analyses and clinical specimens were employed to investigate the relationship between miR-30c-5p and clinical information in BCa patients. The expression levels of miR-30c-5p and its target gene were assessed by real-time PCR and western blot. Cell viability was evaluated through clonogenic capacity, CCK-8, and EdU assays. Cell cycle distribution and cell apoptosis were determined by flow cytometry. The anti-tumor effect of miR-30c-5p was also validated in animal models. RESULTS: The expression levels of miR-30c-5p were significantly decreased in both bladder tumor tissue and BCa cell lines. Low miR-30c-5p expression was found to be correlated with unfavorable TNM stages and poor prognosis. Over-expressing miR-30c-5p was observed to hinder BCa cell growth, migration, and invasion abilities and causing cell cycle arrest. Mechanistically, miR-30c-5p directly binds and suppresses PRC1, thereby blocking the CDK1/Cyclin B1 axis in BCa, thus impairing BCa cell viability and inducing cell cycle arrest at G2/M phase. CONCLUSION: Down-regulated miR-30c-5p promotes BCa through its target gene PRC1, miR-30c-5p is a favorable biomarker for predicting clinical outcomes in BCa patients and has the potential to be a therapeutic target.

CCNB1 is a novel prognostic biomarker and promotes proliferation, migration and invasion in Wilms tumor.

BACKGROUND: Wilms tumour (WT) is a mixed type of embryonal tumour that usually occurs in early childhood. However, our knowledge of the pathogenesis or progression mechanism of WT is inadequate, and there is a scarcity of beneficial therapeutic strategies. METHODS: High-throughput RNA sequencing was employed in this study to identify differentially expressed genes (DEGs) in clinical tumor samples and matching normal tissues. The STRING database was utilized to build a protein-protein interaction (PPI) network, and the Cytohubba method was used to identify the top 10 highly related HUB genes. Then, the key genes were further screened by univariate COX survival analysis. Subsequently, the XCELL algorithm was used to evaluate the tumour immune infiltration. RT-PCR, WB, and IF were used to verify the expression level of key genes in clinical tissues and tumour cell lines. Finally, the function of the key gene was further verified by loss-of-function experiments. RESULTS: We initially screened 1612 DEGs, of which 1030 were up-regulated and 582 were down-regulated. The GO and KEGG enrichment analysis suggested these genes were associated with 'cell cycle', 'DNA replication'. Subsequently, we identified 10 key HUB genes, among them CCNB1 was strongly related to WT patients' overall survival. Multiple survival analyses showed that CCNB1 was an independent indicator of WT prognosis. Thus, we constructed a nomogram of CCNB1 combined with other clinical indicators. Single gene GSEA and immune infiltration analysis revealed that CCNB1 was associated with the degree of infiltration or activation status of multiple immune cells. TIDE analysis indicated that this gene was correlated with multiple key immune checkpoint molecules and TIDE scores. Finally, we validated the differential expression level of CCNB1 in an external gene set, the pan-cancer, clinical samples, and cell lines. CCNB1 silencing significantly inhibited the proliferation, migration, and invasive capabilities of WIT-49 cells, also, promoted apoptosis, and in turn induced G2 phase cell cycle arrest in loss-of-function assays. CONCLUSION: Our study suggests that CCNB1 is closely related to WT progression and prognosis, and serves as a potential target.

A novel transcription factor, BmZFP67, regulates endomitosis switch by controlling the expression of cyclin B in silk glands.

Endomitosis is involved in developmental processes associated with an increase in metabolic cell activity, which is characterized by repeated rounds of DNA replication without cytokinesis. Endomitosis cells are widespread in protozoa, plants, animals and humans. Endomitosis cell cycle is currently viewed as a variation of the canonical cell cycle and transformed from mitotic cell cycle. However, the meaningful question about how endomitosis transformed from mitosis is still unclear. Herein, we identified a novel transcription factor in silk glands, ZFP67, which is gradually reduced in silk glands during the transition of mitosis to endomitosis. In addition, over-expressed ZFP67 in silk glands led to the transition delayed. And, knock-out of ZFP67 led to abnormal chromatin division and unsuccessful cell division. These data reveled that ZFP67 played an important role in transition of mitosis to endomitosis. Furthermore, ZFP67 can regulate the transcription of cyclin B, a key cyclin related to cell division and G2/M phase, which is demonstrated by chromatin immunoprecipitation and dual luciferase reporter system in this article. In conclusion, it can be speculated that the decreasing expression of ZFP67 in silk glands during the transition stage of mitosis-to-endomitosis resulted in the lack of cyclin B, which further led to unsuccessful cytokinesis and then promoted the transition from mitosis to endomitosis of silk gland cells.

Aberrant APOBEC3B Expression in Breast Cancer Is Linked to Proliferation and Cell Cycle Phase.

APOBEC3B (A3B) is aberrantly overexpressed in a subset of breast cancers, where it associates with advanced disease, poor prognosis, and treatment resistance, yet the causes of A3B dysregulation in breast cancer remain unclear. Here, A3B mRNA and protein expression levels were quantified in different cell lines and breast tumors and related to cell cycle markers using RT-qPCR and multiplex immunofluorescence imaging. The inducibility of A3B expression during the cell cycle was additionally addressed after cell cycle synchronization with multiple methods. First, we found that A3B protein levels within cell lines and tumors are heterogeneous and associate strongly with the proliferation marker Cyclin B1 characteristic of the G2/M phase of the cell cycle. Second, in multiple breast cancer cell lines with high A3B, expression levels were observed to oscillate throughout the cell cycle and again associate with Cyclin B1. Third, induction of A3B expression is potently repressed throughout G0/early G1, likely by RB/E2F pathway effector proteins. Fourth, in cells with low A3B, induction of A3B through the PKC/ncNF-κB pathway occurs predominantly in actively proliferating cells and is largely absent in cells arrested in G0. Altogether, these results support a model in which dysregulated A3B overexpression in breast cancer is the cumulative result of proliferation-associated relief from repression with concomitant pathway activation during the G2/M phase of the cell cycle.

Cockayne syndrome group A protein localizes at centrosomes during mitosis and regulates Cyclin B1 ubiquitination.

Mutations in CSA and CSB proteins cause Cockayne syndrome, a rare genetic neurodevelopment disorder. Alongside their demonstrated roles in DNA repair and transcription, these two proteins have recently been discovered to regulate cytokinesis, the final stage of the cell division. This last finding allowed, for the first time, to highlight an extranuclear localization of CS proteins, beyond the one already known at mitochondria. In this study, we demonstrated an additional role for CSA protein being recruited at centrosomes in a strictly determined step of mitosis, which ranges from pro-metaphase until metaphase exit. Centrosomal CSA exerts its function in specifically targeting the pool of centrosomal Cyclin B1 for ubiquitination and proteasomal degradation. Interestingly, a lack of CSA recruitment at centrosomes does not affect Cyclin B1 centrosomal localization but, instead, it causes its lasting centrosomal permanence, thus inducing Caspase 3 activation and apoptosis. The discovery of this unveiled before CSA recruitment at centrosomes opens a new and promising scenario for the understanding of some of the complex and different clinical aspects of Cockayne Syndrome.