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.

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.

BRCA1 deficiency enhances the aggressiveness of breast cancer cells expressing HPV16 oncoproteins.

BACKGROUND INFORMATION: The precise etiology of breast cancer is not completely understood, although women with BRCA1 gene mutations have a significantly increased risk of developing the disease. In addition, sporadic breast cancer is frequently associated with decreased BRCA1 gene expression. Growing evidence of Human papillomaviruses (HPVs) infections in breast tumors has raised the possibility of the involvement of HPVs in the pathogenesis of breast cancer. We investigated whether the effects of HPV oncoproteins E6 and E7 were influenced by the expression levels of BRCA1. HPV16E6E7 (prototype or E6D25E/E7N29S Asian variant type) were stably expressed in MDA-MB231 breast cancer cells, wild type for BRCA1, or with BRCA1 knocked down. RESULTS: Expression of HPV16E6E7 oncogenes did not affect BRCA1 levels and the abundance of HPV16E6E7 was not altered by BRCA1 knockdown. BRCA1 levels did not alter HPV16E6E7-dependent degradation of G1-S cell cycle proteins p53 and pRb. However, we found that the expression of G2-M cell cycle protein cyclin B1 enhanced by HPV16E6E7 was impacted by BRCA1 levels. Especially, we found the correlation between BRCA1 and cyclin B1 expression and this was also confirmed in breast cancer samples from a Thai cohort. We further demonstrated that the combination of HPV oncoproteins and low levels of BRCA1 protein appears to enhance proliferation and invasion. Transactivation activities of HPV16E6E7 on genes regulating cell proliferation and invasion (TGF-ß and vimentin) were significantly increased in BRCA1-deficient cells. CONCLUSIONS: Our results indicate that a deficiency of BRCA1 promotes the transactivation activity of HPV16E6E7 leading to increase of cell proliferation and invasion. SIGNIFICANCE: HPV infection appears to have the potential to enhance the aggressiveness of breast cancers, especially those deficient in BRCA1.

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.

Сopper nanoparticles supported on charcoal and betacellulin - Two novel stimulators of ovarian granulosa cell functions and their functional interrelationships.

The present experiments are aimed to examine the effect of copper nanoparticles supported on charcoal (CuNPs/C), growth factor betacellulin (BTC) and their interrelationships in the control of ovarian cell functions. Porcine ovarian granulosa cells were cultured in the presence of CuNPs/C (0, 1, 10 or 100 ng/ml), BTC (100 ng/ml) and the combination of both, CuNPs/C + BTC. Markers of cell proliferation (BrDU incorporation), of the S-phase (PCNA) and G-phase (cyclin B1) of the cell cycle, markers of extrinsic (nuclear DNA fragmentation) and cytoplasmic/mitochondrial apoptosis (bax and caspase 3), and the release of progesterone and estradiol were assessed by BrDU test, TUNEL, quantitative immunocytochemistry and ELISA. Both CuNPs/C and BTC, when added alone, increased the expression of all the markers of cell proliferation, reduced the expression of all apoptosis markers and stimulated progesterone and estradiol release. Moreover, BTC was able to promote the CuNPs/C action on the accumulation of PCNA, cyclin B1, bax and estradiol output. These observations demonstrate the stimulatory action of both CuNPs/C and BTC on ovarian cell functions, as well as the ability of BTC to promote the action of CuNPs/C on ovarian cell functions.

Inhibition of vinculin activity has an adverse effect on porcine ovarian cells.

The existing knowledge of the involvement of vinculin (VCL) in the control of ovarian cell functions is insufficient. To understand the role of VCL in the control of basic porcine ovarian granulosa cell functions, we decreased VCL activity by small interfering RNA (VCL siRNA). The expression of VCL, accumulation of VCL protein, cell viability, proliferation (accumulation of PCNA and cyclin B1), proportion of proliferative active cells, apoptosis (accumulation of bax, caspase 3, p53, antiapoptotic marker bcl2, and bax/bcl-2 ratio), DNA fragmentation, and release of steroid hormones and IGF-I were analyzed by RT‒qPCR, Trypan blue exclusion test, quantitative immunocytochemistry, XTT assay, TUNEL assay, and ELISA. The suppression of VCL activity inhibited cell viability, the accumulation of the proliferation-related proteins PCNA and cyclin B1, the antiapoptotic protein bcl2, and the proportion of proliferative active cells. Moreover, VCL siRNA inhibited the release of progesterone, estradiol, and IGF-1. VCL siRNA increased the proportion of the proapoptotic proteins bax, caspase 3, p53, the proportion of DNA fragmented cells, and stimulated testosterone release. Taken together, the present study is the first evidence that inhibition of VCL suppresses porcine granulosa cell functions. Moreover, the results suggest that VCL can be a potent physiological stimulator of ovarian functions.

Kielin/chordin-like protein deficiency aggravates pressure overload-induced cardiac dysfunction and remodeling via P53/P21/CCNB1 signaling in mice.

Targeting cardiac remodeling is regarded as a key therapeutic strategy for heart failure. Kielin/chordin-like protein (KCP) is a secretory protein with 18 cysteine-rich domains and associated with kidney and liver fibrosis. However, the relationship between KCP and cardiac remodeling remains unclear. Here, we aimed to investigate the role of KCP in cardiac remodeling induced by pressure overload and explore its potential mechanisms. Left ventricular (LV) KCP expression was measured with real-time quantitative PCR, western blotting, and immunofluorescence staining in pressure overload-induced cardiac remodeling in mice. Cardiac function and remodeling were evaluated in wide-type (WT) mice and KCP knockout (KO) mice by echocardiography, which were further confirmed by histological analysis with hematoxylin and eosin and Masson staining. RNA sequence was performed with LV tissue from WT and KO mice to identify differentially expressed genes and related signaling pathways. Primary cardiac fibroblasts (CFs) were used to validate the regulatory role and potential mechanisms of KCP during fibrosis. KCP was down-regulated in the progression of cardiac remodeling induced by pressure overload, and was mainly expressed in fibroblasts. KCP deficiency significantly aggravated pressure overload-induced cardiac dysfunction and remodeling. RNA sequence revealed that the role of KCP deficiency in cardiac remodeling was associated with cell division, cell cycle, and P53 signaling pathway, while cyclin B1 (CCNB1) was the most significantly up-regulated gene. Further investigation in vivo and in vitro suggested that KCP deficiency promoted the proliferation of CFs via P53/P21/CCNB1 pathway. Taken together, these results suggested that KCP deficiency aggravates cardiac dysfunction and remodeling induced by pressure overload via P53/P21/CCNB1 signaling in mice.

Unraveling the interplay between PKA inhibition and Cdk1 activation during oocyte meiotic maturation.

Oocytes are arrested in prophase I. In vertebrates, meiotic resumption is triggered by hormonal stimulation that results in cAMP-dependent protein kinase (PKA) downregulation leading to Cdk1 activation. Yet the pathways connecting PKA to Cdk1 remain unclear. Here, we identify molecular events triggered by PKA downregulation occurring upstream of Cdk1 activation. We describe a two-step regulation controlling cyclin B1 and Mos accumulation, which depends on both translation and stabilization. Cyclin B1 accumulation is triggered by PKA inhibition upstream of Cdk1 activation, while its translation requires Cdk1 activity. Conversely, Mos translation initiates in response to the hormone, but the protein accumulates only downstream of Cdk1. Furthermore, two successive translation waves take place, the first controlled by PKA inhibition and the second by Cdk1 activation. Notably, Arpp19, an essential PKA effector, does not regulate the early PKA-dependent events. This study elucidates how PKA downregulation orchestrates multiple pathways that converge toward Cdk1 activation and induce the oocyte G2/M transition.

Prognostic value of cyclin B1 and cyclin B2 expression in breast cancer: A systematic review and updated meta-analysis.

BACKGROUND: Cyclin B1 and cyclin B2 are key regulators of cell cycle progression and have been implicated in the prognostic significance of various cancers. This meta-analysis aimed to evaluate the prognostic value of cyclin B1 and B2 expression in breast cancer. METHODS: A comprehensive literature search was conducted on Pubmed, Embase, MEDLINE, Web of Science, and Cochrane library. Studies with survival data and clinicopathological parameters associated with cyclin B1 and B2 or CCNB1 and CCNB2 genes were included. Survival data and clinicopathological parameters associated with cyclin B1 and B2 expression were extracted. Pooled hazard ratios and odds ratios with 95% confidence intervals were calculated. Subgroup analysis was conducted to assess heterogeneity. Publication bias was evaluated. RESULTS: A total of 23 studies were included in the analysis. High expression of cyclin B1 was significantly associated with worse overall survival (hazard ratio [HR] = 1.69, P < .01), disease-specific survival (HR = 1.71, P < .01), and disease-free survival (HR = 2.01, P = .01). High expression of cyclin B2 was associated with worse disease-specific survival (HR = 2.46, P = .02). Clinicopathological parameters did not show significant associations with cyclin B1 and B2 expressions. When data on cyclin B1 and B2 were combined, a significant age-related difference was found (odds ratio = 0.62, P = .04). CONCLUSIONS: This meta-analysis provides evidence supporting the prognostic significance of cyclin B1 and B2 expression in breast cancer. High expression of cyclin B1 and B2 is associated with worse survival, indicating their potential as prognostic markers in breast cancer.

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.

CDCA8 Facilitates Tumor Proliferation and Predicts a Poor Prognosis in Hepatocellular Carcinoma.

CDCA8 expression is abnormally high in a variety of cancers and involved in the biological process of tumor malignancy. In this study, we discovered that the expression of CDCA8 was up-regulated in hepatocellular carcinoma cancer (HCC) tissues and high levels of CDCA8 are associated with larger tumor size, higher AFP (α-fetoprotein) levels, and unfavorable prognosis. Cell functional experiments revealed that CDCA8 silencing remarkably inhibited proliferation and promoted apoptosis in SNU-387 and Hep-3B cells. The results of flow cytometry showed that CDCA8 regulated CDK1 and cyclin B1 expression to arrest at the S phase, inhibited proliferation, and promoted apoptosis. In addition, in vivo studies have confirmed that silencing CDCA8 could regulate CDK1/cyclin B1 signaling axis to inhibit the growth of HCC xenograft tumor. Our study demonstrated CDCA8 acts an oncogene to facilitate cell proliferation of HCC via regulating cell cycle, indicating the promising application value of CDCA8 for HCC diagnosis and clinical treatment.

BubR1 and cyclin B1 immunoexpression in pleomorphic adenoma and polymorphous adenocarcinoma of minor salivary glands.

The immunoexpression of BubR1 and cyclin B1 in pleomorphic adenoma (PA) and polymorphic adenocarcinoma (PAC) in minor salivary glands is poorly studied. Thus, a retrospective and observational study was performed to provide a better understanding of the role and immunopositivity patterns of these proteins in these lesions. Sixteen cases of PA and 16 cases of PAC were selected. Parenchyma cells were submitted to quantitative immunohistochemical analysis through the labeling index. Cytoplasmic immunoexpression of BubR1 was observed in neoplastic cells from all analyzed PA and PAC cases. All PA cases and 93.7% of PAC exhibited nuclear immunoexpression of BubR1. Higher cytoplasmic and nuclear immunoexpression of BubR1 was observed in PAC (p = 0.001 and p = 0.122, respectively). Cytoplasmic immunoexpression of cyclin B1 was observed in all cases of PA and PAC, with a higher labeling index in the latter (p < 0.001). There was a significant positive correlation between nuclear and cytoplasmic BubR1 immunoexpressions (p < 0.001) in PA and a significant negative correlation between BubR1 and cyclin B1 cytoplasmic immunoexpressions (p = 0.014) in PAC. The higher cytoplasmic and nuclear immunoexpression of BubR1 in PACs suggests the continuous maintenance of neoplastic cells in the cell cycle and migration. Higher immunoexpression of cyclin B1 supports this lesion's enhanced proliferative and migration ability.

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.

Resveratrol affects ccRCC cell senescence and macrophage polarization by regulating the stability of CCNB1 by RBM15.

Aim: The present study sought to investigate the therapeutic effect of resveratrol on clear cell renal cell carcinoma. Materials & methods: Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays were used to verify the cell proliferation. Transwell, real-time quantitative transcription PCR, western blot and ß-galactosidase staining were used to verify the migration, macrophage polarization and senescence. The tumor inhibitory effect of resveratrol on clear cell renal cell carcinoma was verified in vivo. Results: This study confirmed that resveratrol could affect the stability of CCNB1 mRNA mediated by RBM15 and inhibit the cancer process by inhibiting the expression of EP300/CBP from the perspective of cell senescence. Conclusion: Resveratrol is able to treat clear cell renal cell carcinoma through RBM15-induced cell senescence.

Role of CCNB1, CENPF, and neutrophils in lung cancer diagnosis and prognosis.

This study aimed to investigate CCNB1, CENPF, and Neutrophils as diagnostic predictors of lung cancer and to explore their association with clinical prognosis. Clinical data were obtained for a total of 52 patients. In addition, we downloaded 555 lung cancer-related samples from the cancer genome atlas (TCGA) database. Differentially expressed genes were further screened. Immune cell infiltration and survival analysis were performed. Immunohistochemistry was used to confirm gene expression. Peripheral blood analysis showed that neutrophil percentages were significantly reduced in patients with lung cancer. The least absolute shrinkage and selection operator and multivariate regression analysis revealed that CCNB1 and CENPF were lung cancer risk factors. Both CCNB1 and CENPF are overexpressed in lung cancer. The clinical diagnostic model constructed using CCNB1, CENPF, and neutrophils had a C-index of 0.994. This model area under the curve (AUC) and internal validation C-index values were 0.994 and 0.993, respectively. The elevated expression of CCNB1 and CENPF showed that the survival rate of lung cancer patients was reduced. CCNB1 and CENPF expression was positively correlated with the clinical stage of lung cancer. Further studies confirmed that CCNB1 and CENPF are overexpressed in lung cancer tissues. The clinically constructed model with high accuracy based on CCNB1, CENPF, and neutrophils demonstrated that these are crucial indicators for lung cancer diagnosis. High expression of CCNB1 and CENPF indicates a poor prognosis in patients with lung cancer.

[Icaritin increases radiosensitivity of nasopharyngeal carcinoma cells by regulating iron death].

OBJECTIVE: To explore the radiosensitizing effect of icaritin on nasopharyngeal carcinoma (NPC) cells and the underlying mechanism. METHODS: MTT assay and clonal formation assay were used to evaluate the effect of icaritin on proliferation of human NPC HONE1 and HNE1 cells. The effects of icaritin treatment, γ-ray radiation, or both on production of reactive oxygen species (ROS), cell cycle distribution and apoptosis of the NPC cells were assessed using flow cytometry. The expressions of DNA damage markers γ-H2AX, cycle-related proteins CDC25C, p-CDC25C and cyclin B1, and ferroptosis markers ACSL4 and GXP4 were detected using Western blotting. A nude mouse model bearing subcutaneous HONE1 cell xenograft was used to observe the effect of icaritin and radiation on tumor growth. RESULTS: Icaritin dose-dependently inhibited the viability of the NPC cells and enhanced the inhibitory effect of radiation on cell proliferation. Flow cytometry and Western blotting showed that icaritin treatment prior to radiation significantly promoted ROS production and γ-H2AX expression in the NPC cells (P<0.001). Compared with radiation exposure alone, the combined treatment caused cell cycle arrest in G2 phase, down-regulated CDC25C and cyclin B1 expression, and up-regulated p-CDC25C expression in the cells (P<0.01), resulting also in increased cell apoptosis, enhanced expression of ferroptosis protein ACSL4 and lowered expression of GXP4 (P<0.001). In the tumor-bearing mice, icaritin treatment, compared with radiation alone, significantly reduced the tumor growth rate and decreased tumor weight (P<0.001). CONCLUSION: Icaritin can enhance radiosensitivity of NPC cells both in vitro and in nude mice possibly by enhancing ROS production to promote iron death of the cells.

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.

[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.

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].