scholarly journals Cyclin D3-CDK6 Complex Facilitates Tumorigenesis by Regulating the C-Myc/miR-15a/16 Axis in a Feedback Loop in Gastric Cancer

2020 ◽  
Author(s):  
Yeting Hong ◽  
Wei He ◽  
Jianbin Zhang ◽  
Lu Shen ◽  
Chong Yu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Feedback Loop ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Cyclin D3 ◽  
Luciferase Reporter

Abstract Background: Cyclin D3-CDK6 complex is a component of the core cell cycle machinery that regulates cell proliferation. By using Human Protein Atlas database, a higher expression level of this complex was found in gastric cancer. However, the function of this complex in gastric cancer remain poorly understood. This study aims to determine the expression pattern of this complex in gastric cancer and to investigate its biological role during tumorigenesis.Methods: To demonstrate that Cyclin D3-CDK6 regulate the c-Myc/miR-15a/16 axis in a feedback loop in gastric cancer, a series of methods were conducted both in vitro and in vivo experiments, including qRT-PCR, western blot analysis, EdU assay, flow cytometry, luciferase reporter assay and immunohistochemical staining. SPSS and Graphpad prism software were used for data analysis.Results: In this study, we found that Cyclin D3 and CDK6 were significantly upregulated in gastric cancer and correlated with poorer overall survival. Further study proved that this complex significantly promoted cell proliferation and cell cycle progression in vitro and accelerated xenografted tumor growth in vivo. Furthermore, we explored the molecular mechanisms through which the complex mediated Rb phosphorylation and then promoted c-Myc expression in vitro, we also found c-Myc could suppress miR-15a/16 expression in gastric cancer cell. Finally, we found that miR-15a/16 can simultaneously regulate Cyclin D3 and CDK6 expression as direct target genes.Conclusions: Our findings uncover the Cyclin D3-CDK6/c-Myc/miR-15a/16 feedback loop axis as a pivotal role in the regulation of gastric cancer tumorigenesis, and this regulating axis may provide a potential therapeutic target for gastric cancer treatment.

scholarly journals LMNB2 Promotes the Progression of Colorectal Cancer by Silencing p21 Expression

2020 ◽  
Author(s):  
Chen-Hua Dong ◽  
Tao Jiang ◽  
Hang Yin ◽  
Hu Song ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Luciferase Reporter ◽  
Cycle Progression ◽  
Cancer Tissues ◽  
P21 Promoter

Abstract Background: Lamin B2 (LMNB2) is involved in chromatin remodelling and the rupture and reorganization of the nuclear membrane during mitosis, which is necessary for eukaryotic cell proliferation. However, there are few reports on the expression and function of LMNB2 in colorectal cancer.Methods: A tissue microarray (TAM) was used to detect the expression of LMNB2 in 226 colorectal cancer tissues and the corresponding adjacent tissues. The CCK-8 colorimetric assay, EdU incorporation analyses, colony formation assays and cell cycle experiments were used to evaluate the effect of LMNB2 on colorectal cancer cell proliferation in vitro, and a mouse tumorigenic model was used to study the effect of LMNB2 on colorectal cancer cells in vivo. The main pathways and genes regulated by LMNB2 were detected by RNA sequencing. Dual-luciferase reporter assays were conducted to test the direct binding between LMNB2 and p21, and ChIP analysis showed that LMNB2 promotes cell proliferation by regulating the p21 promoter.Results: The results showed that LMNB2 expression is increased in colorectal cancer tissues. Highly expressed LMNB2 is associated with tumour size and TNM stage. Multivariate Cox analysis showed that LMNB2 can be used as an independent prognostic factor in patients with colorectal cancer. Functional assays indicated that LMNB2 obviously enhanced cell proliferation by promoting cell cycle progression in vitro and in vivo. LMNB2 facilitates cell proliferation via regulating the p21 promoter, whereas LMNB2 had no effect on cell apoptosis in terms of mechanism.Conclusion: LMNB2 promotes the proliferation of colorectal cancer by regulating p21-mediated cell cycle progression, indicating the potential value of LMNB2 as a clinical prognostic marker and molecular therapeutic target.

scholarly journals The POU2F1/miR-4490/USP22 axis regulates cell proliferation and metastasis in gastric cancer

2020 ◽  
Vol 43 (6) ◽  
pp. 1017-1033 ◽  
Author(s):  
Yizhi Xiao ◽  
Side Liu ◽  
Jiaying Li ◽  
Weiyu Dai ◽  
Weimei Tang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Epithelial Mesenchymal Transition ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Aberrant Expression ◽  
Mesenchymal Transition

Abstract Purpose Growing evidence indicates that aberrant expression of microRNAs contributes to tumor development. However, the biological role of microRNA-4490 (miR-4490) in gastric cancer (GC) remains to be clarified. Methods To explore the function of miR-4490 in GC, we performed colony formation, EdU incorporation, qRT-PCR, Western blotting, in situ hybridization (ISH), immunohistochemistry (IHC), flow cytometry, ChIP and dual-luciferase reporter assays. In addition, the growth, migration and invasion capacities of GC cells were evaluated. Results We found that miR-4490 was significantly downregulated in primary GC samples and in GC-derived cell lines compared with normal controls, and that this expression level was negatively correlated with GC malignancy. Exogenous miR-4490 expression not only reduced cell cycle progression and proliferation, but also significantly inhibited GC cell migration, invasion and epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, we found that miR-4490 directly targets USP22, which mediates inhibition of GC cell proliferation and EMT-induced metastasis in vitro and in vivo. Moreover, we found through luciferase and ChIP assays that transcription factor POU2F1 can directly bind to POU2F1 binding sites within the miR-4490 and USP22 promoters and, by doing so, modulate their transcription. Spearman’s correlation analysis revealed a positive correlation between USP22 and POU2F1 expression and negative correlations between miR-4490 and USP22 as well as miR-4490 and POU2F1 expression in primary GC tissues. Conclusion Based on our results we conclude that miR-4490 acts as a tumor suppressor, and that the POU2F1/miR-4490/USP22 axis plays an important role in the regulation of growth, invasion and EMT of GC cells.

scholarly journals LncRNA LINC00337 Sponges miR-1285-3p to Promote Proliferation and Metastasis of Lung Adenocarcinoma Cells Through Up-Regulating YTHDF1

2020 ◽  
Author(s):  
Ru-nan Zhang ◽  
Dong-mei Wu ◽  
Li-ping Wu ◽  
Guo-wei Gao
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Lung Adenocarcinoma ◽  
Molecular Mechanisms ◽  
Luciferase Reporter ◽  
Gear Up ◽  
Knock Down ◽  
Reporter Assays

Abstract Background: Emerging studies have attested that long noncoding RNAs (lncRNAs) predominantly functioned in carcinogenesis of multiple developing human tumors. The current research aimed at probing the underlying participation and mechanisms of LINC00337 in lung adenocarcinoma.Methods: Here we analyzed TCGA and GTEx datasets and chose LINC00337 as research object. Cell proliferation, cell apoptosis, cell cycle, and invasion were detected in gain and loss experiment of LINC00337 both in vitro and in vivo. Moreover, RNA pull-down, luciferase reporter assays, western blotting analysis, rescue experiment were performed to investigate underlying molecular mechanisms of LINC00337 function. Results: LINC00337 was remarkably increased in lung adenocarcinoma. Also, LINC00337 knock-down was unraveled to repress cell invasion and proliferation as well as cell cycle, and gear up apoptosis in lung adenocarcinoma in vitro and in vivo. With respect to mechanism, LINC00337 knock-down boosted miR-1285-3p to be expressed and then restrained YTHDF1 to be expressed post-transcriptionally. Crucially, both miR-1285-3p decrement and YTHDF1 overexpression successfully countered the influence on cell proliferation, invasion and apoptosis caused by LINC00337 shRNA.Conclusions: These results suggest that LINC00337 acted as an oncogenic lncRNA, targeting miR-1285-3p and regulating YTHDF1 expression, to promote the progression of lung adenocarcinoma.

scholarly journals LncRNA LINC00337 sponges mir-1285-3p to promote proliferation and metastasis of lung adenocarcinoma cells by upregulating YTHDF1

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ru-nan Zhang ◽  
Dong-mei Wu ◽  
Li-ping Wu ◽  
Guo-wei Gao
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Lung Adenocarcinoma ◽  
Molecular Mechanisms ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Gear Up ◽  
Underlying Mechanisms

Abstract Background Emerging studies have shown that long noncoding RNAs (lncRNAs) predominantly function in the carcinogenesis of multiple developing human tumors. The current study aimed to investigate the underlying mechanisms of LINC00337 in lung adenocarcinoma. Methods We analyzed TCGA and GTEx datasets and chose LINC00337 as the research object. Cell proliferation, cell apoptosis, cell cycle, migration, and invasion were detected in the gain and loss experiments of LINC00337 both in vitro and in vivo. Moreover, RNA pull-down, luciferase reporter assays, western blotting analysis, and rescue experiments were performed to investigate the underlying molecular mechanisms of LINC00337 function. Results LINC00337 expression was remarkably upregulated in lung adenocarcinoma. In addition, LINC00337 knockdown was shown to repress cell migration, invasion, and proliferation, as well as the cell cycle, and gear up apoptosis in lung adenocarcinoma in vitro and in vivo. With respect to the mechanism, LINC00337 knockdown boosted miR-1285-3p expression and then restrained YTHDF1 expression post-transcriptionally. Crucially, both miR-1285-3p decrement and YTHDF1 overexpression successfully reversed the influence on cell proliferation, migration, invasion, and apoptosis caused by LINC00337 shRNA. Conclusions These results suggest that LINC00337 acts as an oncogenic lncRNA, targeting miR-1285-3p and regulating YTHDF1 expression, to promote the progression of lung adenocarcinoma.

scholarly journals LMNB2 promotes the progression of colorectal cancer by silencing p21 expression

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Chen-Hua Dong ◽  
Tao Jiang ◽  
Hang Yin ◽  
Hu Song ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Gene Set Enrichment Analysis ◽  
Molecular Therapy ◽  
Cycle Progression ◽  
Cancer Tissues

AbstractColorectal cancer is the second common cause of death worldwide. Lamin B2 (LMNB2) is involved in chromatin remodeling and the rupture and reorganization of nuclear membrane during mitosis, which is necessary for eukaryotic cell proliferation. However, the role of LMNB2 in colorectal cancer (CRC) is poorly understood. This study explored the biological functions of LMNB2 in the progression of colorectal cancer and explored the possible molecular mechanisms. We found that LMNB2 was significantly upregulated in primary colorectal cancer tissues and cell lines, compared with paired non-cancerous tissues and normal colorectal epithelium. The high expression of LMNB2 in colorectal cancer tissues is significantly related to the clinicopathological characteristics of the patients and the shorter overall and disease-free cumulative survival. Functional analysis, including CCK8 cell proliferation test, EdU proliferation test, colony formation analysis, nude mouse xenograft, cell cycle, and apoptosis analysis showed that LMNB2 significantly promotes cell proliferation by promoting cell cycle progression in vivo and in vitro. In addition, gene set enrichment analysis, luciferase report analysis, and CHIP analysis showed that LMNB2 promotes cell proliferation by regulating the p21 promoter, whereas LMNB2 has no effect on cell apoptosis. In summary, these findings not only indicate that LMNB2 promotes the proliferation of colorectal cancer by regulating p21-mediated cell cycle progression, but also suggest the potential value of LMNB2 as a clinical prognostic marker and molecular therapy target.

scholarly journals Positive feedback between lncRNA FLVCR1-AS1 and KLF10 may inhibit pancreatic cancer progression via the PTEN/AKT pathway

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Jiewei Lin ◽  
Shuyu Zhai ◽  
Siyi Zou ◽  
Zhiwei Xu ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Pancreatic Cancer ◽  
Cell Proliferation ◽  
Cancer Progression ◽  
Positive Feedback ◽  
Molecular Mechanisms ◽  
Tumor Tissues ◽  
And Migration

Abstract Background FLVCR1-AS1 is a key regulator of cancer progression. However, the biological functions and underlying molecular mechanisms of pancreatic cancer (PC) remain unknown. Methods FLVCR1-AS1 expression levels in 77 PC tissues and matched non-tumor tissues were analyzed by qRT-PCR. Moreover, the role of FLVCR1-AS1 in PC cell proliferation, cell cycle, and migration was verified via functional in vitro and in vivo experiments. Further, the potential competitive endogenous RNA (ceRNA) network between FLVCR1-AS1 and KLF10, as well as FLVCR1-AS1 transcription levels, were investigated. Results FLVCR1-AS1 expression was low in both PC tissues and PC cell lines, and FLVCR1-AS1 downregulation was associated with a worse prognosis in patients with PC. Functional experiments demonstrated that FLVCR1-AS1 overexpression significantly suppressed PC cell proliferation, cell cycle, and migration both in vitro and in vivo. Mechanistic investigations revealed that FLVCR1-AS1 acts as a ceRNA to sequester miR-513c-5p or miR-514b-5p from the sponging KLF10 mRNA, thereby relieving their suppressive effects on KLF10 expression. Additionally, FLVCR1-AS1 was shown to be a direct transcriptional target of KLF10. Conclusions Our research suggests that FLVCR1-AS1 plays a tumor-suppressive role in PC by inhibiting proliferation, cell cycle, and migration through a positive feedback loop with KLF10, thereby providing a novel therapeutic strategy for PC treatment.

scholarly journals Tumor quiescence: elevating SOX2 in diverse tumor cell types downregulates a broad spectrum of the cell cycle machinery and inhibits tumor growth

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ethan P. Metz ◽  
Erin L. Wuebben ◽  
Phillip J. Wilder ◽  
Jesse L. Cox ◽  
Kaustubh Datta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cell Cycle Machinery

Abstract Background Quiescent tumor cells pose a major clinical challenge due to their ability to resist conventional chemotherapies and to drive tumor recurrence. Understanding the molecular mechanisms that promote quiescence of tumor cells could help identify therapies to eliminate these cells. Significantly, recent studies have determined that the function of SOX2 in cancer cells is highly dose dependent. Specifically, SOX2 levels in tumor cells are optimized to promote tumor growth: knocking down or elevating SOX2 inhibits proliferation. Furthermore, recent studies have shown that quiescent tumor cells express higher levels of SOX2 compared to adjacent proliferating cells. Currently, the mechanisms through which elevated levels of SOX2 restrict tumor cell proliferation have not been characterized. Methods To understand how elevated levels of SOX2 restrict the proliferation of tumor cells, we engineered diverse types of tumor cells for inducible overexpression of SOX2. Using these cells, we examined the effects of elevating SOX2 on their proliferation, both in vitro and in vivo. In addition, we examined how elevating SOX2 influences their expression of cyclins, cyclin-dependent kinases (CDKs), and p27Kip1. Results Elevating SOX2 in diverse tumor cell types led to growth inhibition in vitro. Significantly, elevating SOX2 in vivo in pancreatic ductal adenocarcinoma, medulloblastoma, and prostate cancer cells induced a reversible state of tumor growth arrest. In all three tumor types, elevation of SOX2 in vivo quickly halted tumor growth. Remarkably, tumor growth resumed rapidly when SOX2 returned to endogenous levels. We also determined that elevation of SOX2 in six tumor cell lines decreased the levels of cyclins and CDKs that control each phase of the cell cycle, while upregulating p27Kip1. Conclusions Our findings indicate that elevating SOX2 above endogenous levels in a diverse set of tumor cell types leads to growth inhibition both in vitro and in vivo. Moreover, our findings indicate that SOX2 can function as a master regulator by controlling the expression of a broad spectrum of cell cycle machinery. Importantly, our SOX2-inducible tumor studies provide a novel model system for investigating the molecular mechanisms by which elevated levels of SOX2 restrict cell proliferation and tumor growth.

The Cold-Shock Domain Protein YB-1 Is Important for Cellular Proliferation and the Prevention of Premature Senescence.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2571-2571
Author(s):  
Zhi Hong Lu ◽  
Jason T. Books ◽  
Timothy James Ley
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Binding Proteins ◽  
Cellular Proliferation ◽  
Cold Shock ◽  
Premature Senescence ◽  
Cycle Progression

Abstract Mammalian proteins containing “cold-shock” domains belong to the most evolutionarily conserved family of nucleic acid-binding proteins known in bacteria, plants, and animals. One of these proteins, YB-1, has been implicated in basic cellular functions such as cell proliferation and responses to environmental stresses. In mammalian cells, YB-1 has been shown to shuttle between the nuclear and cytoplasmic compartments. Within the nucleus, YB-1 interacts with several DNA-and pre-mRNA-binding proteins, and has been implicated in nuclear activities, including transcriptional regulation, chromatin remodeling, and pre-mRNA splicing. YB-1 is also abundant in the cytoplasm, where it binds nonspecifically to mRNA, and may act as a general regulator of mRNA stability, cytoplasmic localization, and translation. Thus, YB-1 has been proposed to function as a multifunctional regulator for the control of gene expression in both the nucleus and cytoplasm. YB-1 overexpression has been frequently detected in a variety of human cancers, often associated with unfavorable clinical outcomes. However, it remains unclear whether YB-1 overexpression contributes directly to the malignant phenotype, or whether it is simply a non-causal “marker” associated with rapid cell growth (and poor prognostic outcomes). To further assess the role of this protein in health and disease, we created mice deficient for YB-1. Complete loss of function of this gene results in fully-penetrant late embryonic and perinatal lethality. Morphological and histological analyses revealed that YB-1−/− embryos displayed major developmental and functional defects, including neurological abnormalities, hemorrhage, and respiratory failure, which probably contributed to lethality. Growth retardation occurred in all late-stage embryos, and was the result of hypoplasia in multiple organ systems. Consistent with these in vivo results, fibroblasts isolated from YB-1−/− embryos (MEFs) grew slowly and entered senescence prematurely in vitro; these defects were rescued by ectopic expression of a GFP-tagged human YB-1 cDNA. This data suggests that YB-1 plays an important cell-autonomous role in cell proliferation and prevention of premature senescence. We further showed that loss of YB-1 in early passage MEFs resulted a delay in G0/G1 to S-phase progression, and a defect in a transcriptional mechanism that normally represses the expression of the G1-specific CDK inhibitor gene p16Ink4a, and the p53 target genes p21Cip1 and Mdm2. However, YB-1 does not cause “global” changes in the transcriptome, the proteome, or protein synthesis efficiency. As predicted, p16Ink4a and p21Cip1 double knockdown by siRNA treatment led to an increase in the rate of cell proliferation, and an extension of proliferative capacity during late passages in YB-1−/− cells. Furthermore, YB-1 deficiency reduced the ability of MEFs to proliferate normally in response to c-Myc overexpression. In conclusion, our data has revealed that YB-1 is required for normal mouse development and survival, and that it plays an important role in supporting rapid cellular proliferation both in vivo and in vitro. Our data further suggests that YB-1 is a cell cycle progression regulator that is important for preventing the early onset of senescence in cultured MEF cells. This data raises the possibility that disregulated expression of YB-1 may contribute to malignant phenotypes by supporting rapid cell cycle progression, and by protecting cells from cytotoxic stresses.

scholarly journals Cyclin A expression is under negative transcriptional control during the cell cycle.

1996 ◽  
Vol 16 (7) ◽  
pp. 3789-3798 ◽  
Author(s):  
X Huet ◽  
J Rech ◽  
A Plet ◽  
A Vié ◽  
J M Blanchard
Keyword(s):  
Cell Cycle ◽  
Transcriptional Repression ◽  
Transcriptional Control ◽  
Cell Cycle Progression ◽  
Cyclin A ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Proliferating Cells

Transcription of the gene coding for cyclin A, a protein required for S-phase transit, is cell cycle regulated and is restricted to proliferating cells. To further explore transcriptional regulation linked to cell division cycle control, a genomic clone containing 5' flanking sequences of the murine cyclin A gene was isolated. When it was fused to a luciferase reporter gene, it was shown to function as a proliferation-regulated promoter in NIH 3T3 cells. Transcription of the mouse cyclin A gene is negatively regulated by arrest of cell proliferation. A mutation of a GC-rich sequence conserved between mice and humans is sufficient to relieve transcriptional repression, resulting in a promoter with constitutively high activity. In agreement with this result, in vivo footprinting reveals a protection of the cell cycle-responsive element in G0/early G1 cells which is not observed at later stages of the cell cycle. Moreover, the footprint is present in dimethyl sulfoxide-induced differentiating and not in proliferating Friend erythroleukemia cells. Conversely, two other sites, which in vitro bind ATF-1 and NF-Y, respectively, are constitutively occupied throughout cell cycle progression.

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