Expression of Minichromosome Maintenance 2 (MCM2), Ki-67, and Cell-Cycle-Related Molecules, and Apoptosis in the Normal-Dysplasia-Carcinoma Sequence of the Oral Mucosa

Pathobiology ◽  
2001 ◽  
Vol 69 (3) ◽  
pp. 150-158 ◽  
Author(s):  
Isamu Kodani ◽  
Kohei Shomori ◽  
Mitsuhiko Osaki ◽  
Itaru Kuratate ◽  
Kazuo Ryoke ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Oral Mucosa ◽  
Minichromosome Maintenance ◽  
Ki 67

Cell cycle-dependent reactivity with the monoclonal antibody Ki-67 during myeloid cell differentiation

1988 ◽  
Vol 179 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Robert P. Wersto ◽  
Fritz Herz ◽  
Robert E. Gallagher ◽  
Leopold G. Koss
Keyword(s):  
Cell Cycle ◽  
Monoclonal Antibody ◽  
Cell Differentiation ◽  
Myeloid Cell ◽  
Ki 67 ◽  
Cycle Dependent

scholarly journals MCM3 upregulation confers endocrine resistance in breast cancer and is a predictive marker of diminished tamoxifen benefit

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Sanne Løkkegaard ◽  
Daniel Elias ◽  
Carla L. Alves ◽  
Martin V. Bennetzen ◽  
Anne-Vibeke Lænkholm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Patients ◽  
Endocrine Therapy ◽  
Endocrine Resistance ◽  
Predictive Marker ◽  
Endocrine Treatment ◽  
Breast Cancer Patients ◽  
Minichromosome Maintenance ◽  
Primary Tumors

AbstractResistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in the cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317), and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Interestingly, the MCM3 levels did not affect the efficacy of growth inhibitory by CDK4/6 inhibitors. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic marker adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.

The murine Ki-67 cell proliferation antigen accumulates in the nucleolar and heterochromatic regions of interphase cells and at the periphery of the mitotic chromosomes in a process essential for cell cycle progression

1996 ◽  
Vol 109 (1) ◽  
pp. 143-153 ◽  
Author(s):  
M. Starborg ◽  
K. Gell ◽  
E. Brundell ◽  
C. Hoog
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Tandem Repeats ◽  
Sequence Motifs ◽  
Mitotic Chromosomes ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Cycle Progression ◽  
Conserved Sequence ◽  
Interphase Cells

We have isolated the murine homologue of the human Ki-67 antigen. The Ki-67 antigen is used as a marker to assess the proliferative capacity of tumour cells; however, its cellular function is not known. The murine Ki-67 cDNA sequence (TSG126) was found to contain 13 tandem repeats, making up more than half of the total protein size. A comparison of this repetitive sequence block to its human counterpart, which contains 16 consecutive repeat units, revealed several conserved sequence motifs, including one motif frequently observed in proteins interacting with DNA. An antiserum developed against the product of the TSG126 cDNA clone identified a protein with an apparent molecular mass of 360 kDa, mainly expressed in proliferating cells. The TSG126 protein begins to accumulate during the late G1 stage of the cell cycle and is first seen as numerous small granules evenly distributed throughout the nucleus. During the S and the G2 phases, larger foci that overlap with the nucleoli and the heterochromatic regions are formed. At the onset of mitosis the TSG126 protein undergoes a dramatic redistribution process and becomes associated with the surface of the condensed chromosomes. The relative absence of the TSG126 protein from G1 interphase cells strongly argues against a model where the association of the TSG126 protein with mitotic chromosomes merely reflects a mechanism for the symmetrical distribution of nucleolar proteins between daughter cells. Instead, the intracellular distribution of the TSG126 protein during the cell cycle suggests that it could have a chromatin-associated function in both interphase and mitotic cells. Microinjection of anti-TSG126 antibodies into proliferating Swiss-3T3 fibroblasts was found to delay cell cycle progression, indicating that the TSG126 protein has an essential nuclear function.

scholarly journals Drosophila Minichromosome Maintenance 6 Is Required for Chorion Gene Amplification and Genomic Replication

2002 ◽  
Vol 13 (2) ◽  
pp. 607-620 ◽  
Author(s):  
Gina Schwed ◽  
Noah May ◽  
Yana Pechersky ◽  
Brian R. Calvi
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Genetic Dissection ◽  
Minichromosome Maintenance ◽  
Multiple Origins ◽  
Origin Licensing ◽  
Mcm Complex ◽  
Mcm Proteins ◽  
Prereplicative Complex ◽  
Cycle Regulation

Duplication of the eukaryotic genome initiates from multiple origins of DNA replication whose activity is coordinated with the cell cycle. We have been studying the origins of DNA replication that control amplification of eggshell (chorion) genes duringDrosophila oogenesis. Mutation of genes required for amplification results in a thin eggshell phenotype, allowing a genetic dissection of origin regulation. Herein, we show that one mutation corresponds to a subunit of the minichromosome maintenance (MCM) complex of proteins, MCM6. The binding of the MCM complex to origins in G1 as part of a prereplicative complex is critical for the cell cycle regulation of origin licensing. We find that MCM6 associates with other MCM subunits during amplification. These results suggest that chorion origins are bound by an amplification complex that contains MCM proteins and therefore resembles the prereplicative complex. Lethal alleles of MCM6 reveal it is essential for mitotic cycles and endocycles, and suggest that its function is mediated by ATP. We discuss the implications of these findings for the role of MCMs in the coordination of DNA replication during the cell cycle.

Assessment of the ultrastructural and proliferative properties of human embryonic stem cell-derived cardiomyocytes

2003 ◽  
Vol 285 (6) ◽  
pp. H2355-H2363 ◽  
Author(s):  
Mirit Snir ◽  
Izhak Kehat ◽  
Amira Gepstein ◽  
Raymond Coleman ◽  
Joseph Itskovitz-Eldor ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Late Stage ◽  
Human Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Es Cell ◽  
Cardiomyocyte Proliferation ◽  
Ki 67

Assessment of early ultrastructural development and cell-cycle regulation in human cardiac tissue is significantly hampered by the lack of a suitable in vitro model. Here we describe the possible utilization of human embryonic stem cell (ES) lines for investigation of these processes. With the use of the embryoid body (EB) differentiation system, human ES cell-derived cardiomyocytes at different developmental stages were isolated and their histomorphometric, ultrastructural, and proliferative properties were characterized. Histomorphometric analysis revealed an increase in cell length, area, and length-to-width ratio in late-stage EBs (>35 days) compared with early (10–21 days) and intermediate (21–35 days) stages. This was coupled with a progressive ultrastructural development from an irregular myofibrillar distribution to an organized sarcomeric pattern. Cardiomyocyte proliferation, assessed by double labeling with cardiac-specific antibodies and either [3H]thymidine incorporation or Ki-67 immunolabeling, demonstrated a gradual withdrawal from cell cycle. Hence, the percentage of positively stained nuclei in early-stage cardiomyocytes ([3H]thymidine: 60 ± 10%, Ki-67: 54 ± 23%) decreased to 36 ± 7% and 9 ± 16% in intermediate-stage EBs and to <1% in late-stage cardiomyocytes. In conclusion, a reproducible temporal pattern of early cardiomyocyte proliferation, cell-cycle withdrawal, and ultrastructural maturation was noted in this model. Establishment of this unique in vitro surrogate system may allow to examine the molecular mechanisms underlying these processes and to assess interventions aiming to modify these properties. Moreover, the detailed characterization of the ES cell-derived cardiomyocyte may be crucial for the development of future cell replacement strategies aiming to regenerate functional myocardium.

scholarly journals LncRNA SNHG12 regulates the radiosensitivity of cervical cancer through the miR-148a/CDK1 pathway

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Chen Wang ◽  
Shiqing Shao ◽  
Li Deng ◽  
Shelian Wang ◽  
Yongyan Zhang
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Tumor Growth ◽  
Luciferase Reporter ◽  
Tunel Staining ◽  
Cell Cycle Distribution ◽  
Ki 67 ◽  
In Vivo Experiments ◽  
Potential Biomarker

Abstract Background Radiation resistance is a major obstacle to the prognosis of cervical cancer (CC) patients. Many studies have confirmed that long non-coding RNAs (lncRNAs) are involved in the regulation of radiosensitivity of cancers. However, whether small nucleolar RNA host gene 12 (SNHG12) regulates the radiosensitivity of CC remains unknown. Methods Quantitative real-time polymerase chain reaction was used to measure the expression levels of SNHG12 and microRNA-148a (miR-148a). The radiosensitivity of cells was evaluated by clonogenic assay. Flow cytometry and caspase-3 activity assay were performed to assess the apoptosis ability and cell cycle distribution of cells. Besides, dual-luciferase reporter and RNA immunoprecipitation assay were used to verify the interaction between miR-148a and SNHG12 or cyclin-dependent kinase 1 (CDK1). Also, the protein levels of CDK1, CCND1 and γ-H2AX were detected by western blot analysis. Furthermore, in vivo experiments were conducted to verify the effect of SNHG12 on CC tumor growth. Ki-67 and TUNEL staining were employed to evaluate the proliferation and apoptosis rates in vivo. The hematoxylin and eosin (HE) staining were employed to evaluate the tumor cell morphology. Results SNHG12 was upregulated in CC tissues and cells, and its knockdown improved the radiosensitivity by promoting the radiation-induced apoptosis and cell cycle arrest of CC cells. Also, miR-148a could be sponged by SNHG12 and could target CDK1. MiR-148a inhibitor or CDK1 overexpression could invert the promotion effect of silenced-SNHG12 on CC radiosensitivity. Meanwhile, SNHG12 interference reduced the tumor growth of CC, increased miR-148a expression, and inhibited CDK1 level in vivo. Conclusion LncRNA SNHG12 promoted CDK1 expression to regulate the sensitivity of CC cells to radiation through sponging miR-148a, indicating that SNHG12 could be used as a potential biomarker to treat the radiotherapy resistance of CC patients.

scholarly journals MCM7 Ubiquitination Regulates CMG Helicase Disassembly in Human

2021 ◽  
Author(s):  
Qianqian Sun ◽  
Kun Liu ◽  
Fangzhou Li ◽  
Bingquan Qiu ◽  
Zhisong Fu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Genome Stability ◽  
Human Tumor ◽  
Cell Fractionation ◽  
Minichromosome Maintenance ◽  
E3 Ligases ◽  
Minichromosome Maintenance Protein ◽  
Fork Stalling

Abstract BackgroundThe disassembly of the replisome plays an essential role in maintaining genome stability at the termination of DNA replication. However, the mechanism of replisome disassembly remains unknown in human. In this study, we screened E3 ligases and deubiquitinases (DUBs) for the ubiquitination of minichromosome maintenance protein (MCM) 7 and provided evidence of this process driving CMG helicase disassembly in human tumor cells. MethodsSILAC-MS/MS was analyzed to identify ubiquitinated proteins in HeLa cells. The ubiquitination/deubiquitylation assay in vitro and in vivo were detected by Western blot. Thymidine and HU were implied to synchronized cell cycle，and detect the role of ubiquitinated MCM7 in cell cycle. Cell fractionation assay was used to detect the function of ubiquitination of MCM7 in chromatin and non-chromatin. Aphidicolin、Etoposide、ICRF-193 and IR were applied to cause replication fork stalling. MG-132 and NMS-873 were used to inhibit the proteasome degradation and p97 segregase. Flow cytometer and FlowJo flow cytometry software were used to cell cycle analysis.ResultsIn our study, we found that the ubiquitin ligase RNF8 catalyzes the k63-linked poly-ubiquitination of MCM7 both in vivo and in vitro, and lysine 145 of MCM7 is the primary ubiquitination site. Moreover, the poly-ubiquitination of MCM7 mainly exists in the chromatin, which is dynamically regulated by the cell cycle, mainly occurs in the late S phase. And DNA damage can significantly reduce the poly-ubiquitylation of MCM7 in the late S phage. Furthermore, the proteasome, p97 segregase, USP29 and ATXN3 are required for the removal of MCM7 ubiquitination to promote the disassembly of CMG on chromatin. ConclusionsIn the late S phage of cell cycle, RNF8 catalyzes the poly-ubiquitination of MCM7, and then initiates the disassembly of CMG helicase from chromatin, which is mediated by p97, proteasome, USP29 and ATXN3 in human. We reveal the novel function of the poly-ubiquitylation of MCM7, which is a regulatory signal to control CMG complex unloading at replication termination sites.

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