scholarly journals ei24, a p53 Response Gene Involved in Growth Suppression and Apoptosis

2000 ◽  
Vol 20 (1) ◽  
pp. 233-241 ◽  
Author(s):  
Zhengming Gu ◽  
Cathy Flemington ◽  
Thomas Chittenden ◽  
Gerard P. Zambetti
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Apoptotic Cell ◽  
Functional Characterization ◽  
Growth Control ◽  
P53 Tumor Suppressor ◽  
Cycle Arrest ◽  
P53 Response

ABSTRACT DNA damage and/or hyperproliferative signals activate the wild-type p53 tumor suppressor protein, which induces a G1 cell cycle arrest or apoptosis. Although the mechanism of p53-mediated cell cycle arrest is fairly well defined, the p53-dependent pathway regulating apoptosis is poorly understood. Here we report the functional characterization of murine ei24 (also known asPIG8), a gene directly regulated by p53, whose overexpression negatively controls cell growth and induces apoptotic cell death. Ectopic ei24 expression markedly inhibits cell colony formation, induces the morphological features of apoptosis, and reduces the number of β-galactosidase-marked cells, which is efficiently blocked by coexpression of Bcl-XL. Theei24/PIG8 gene is localized on human chromosome 11q23, a region frequently altered in human cancers. These results suggest that ei24 may play an important role in negative cell growth control by functioning as an apoptotic effector of p53 tumor suppressor activities.

A Stapled p53 Helix Targets HDMX to Overcome Nutlin-3 Resistance and Reactivate the p53 Tumor Suppressor Pathway in Cancer

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2645-2645
Author(s):  
Federico Bernal ◽  
Mark Wade ◽  
Amy M. Silverstein ◽  
Gregory L. Verdine ◽  
Geoffrey M. Wahl ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Cancer Cells ◽  
Ubiquitin Ligase ◽  
Human Cancer ◽  
Transactivation Domain ◽  
Binding Interaction ◽  
P53 Tumor Suppressor ◽  
Cycle Arrest

Abstract p53 is a transcription factor that induces cell cycle arrest or apoptosis in response to DNA damage and cellular stress, and thereby plays a critical role in protecting cells from malignant transformation. The E3 ubiquitin ligase HDM2 controls p53 levels through a direct binding interaction that neutralizes the transactivation activity of p53 and targets it for degradation via the ubiquitylation-proteasomal pathway. Whereas the HDM2-homologue HDMX lacks ubiquitin ligase function, it participates in regulating the p53 axis by heterodimerizing with HDM2 and sequestering p53 through protein interaction. Loss of p53 activity, either by deletion, mutation, or HDM2/HDMX overexpression, is the most common defect in human cancer. Tumors expressing wild type p53 are rendered vulnerable by pharmacologic approaches that stabilize and upregulate p53. In this context, HDM2 and HDMX have emerged as independent therapeutic targets for restoring p53 activity and resensitizing cancer cells to apoptosis in vitro and in vivo. The small molecule nutlin-3 is an effective antagonist of the p53-HDM2 interaction. However, several studies have demonstrated the inability of nutlin-3 to disrupt the p53-HDMX complex, rendering tumor cells that overexpress HDMX nutlin-3-resistant. We have previously described the synthesis and characterization of a hydrocarbon-stapled alpha-helical p53 peptide (SAH-p53-8) that binds HDM2 with low nanomolar affinity, targets HDM2 in situ, and reactivates the p53 tumor suppressor pathway in HDM2-overexpressing osteosarcoma cells. We now report that SAH-p53-8 binds HDMX with even higher affinity, co-immunoprecipitates with endogenous HDMX, and induces apoptosis and cell cycle arrest in nutlin-3-resistant cancer cells that overexpress HDMX. Thus, by inserting a chemical staple into a peptide fragment of the p53 transactivation domain, we have generated the first bifunctional inhibitor of HDM2 and HDMX, enabling the investigation and pharmacologic modulation of both targets in human cancer.

scholarly journals mdm-2 inhibits the G1 arrest and apoptosis functions of the p53 tumor suppressor protein.

1996 ◽  
Vol 16 (5) ◽  
pp. 2445-2452 ◽  
Author(s):  
J Chen ◽  
X Wu ◽  
J Lin ◽  
A J Levine
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Biological Activities ◽  
Tumor Suppressor Protein ◽  
G1 Arrest ◽  
Physical Interaction ◽  
P53 Tumor Suppressor ◽  
Cycle Arrest ◽  
P53 Tumor Suppressor Protein

The mdm-2 gene encodes a 90-kDa polypeptide that binds specifically to the p53 tumor suppressor protein. This physical interaction results in the inhibition of the transcriptional functions of p53 (J. Chen, J. Lin, and A. J. Levine, Mol. Med. 1:142-152, 1995, and J. Momand, G. P. Zambetti, D. C. Olson, D. George, and A. J. Levine, Cell 69:1237-1245, 1992). Experiments are described that demonstrate the ability of mdm-2 to abrogate both the p53-mediated cell cycle arrest and the apoptosis functions. In addition, the results presented here suggest that mdm-2 binding to p53 and the resultant inhibition of p53 transcription functions are critical for reversing p53-mediated cell cycle arrest. The N-terminal half or domain of the mdm-2 protein is sufficient to regulate these biological activities of p53, consistent with the possibility that the highly conserved central acidic region and the C-terminal putative zinc fingers of mdm-2 may encode other functions.

scholarly journals p53: The Attractive Tumor Suppressor in the Cancer Research Field

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Toshinori Ozaki ◽  
Akira Nakagawara
Keyword(s):  
Cell Cycle ◽  
Cancer Research ◽  
Cell Death ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Apoptotic Cell ◽  
Genetic Alterations ◽  
Research Field ◽  
Apoptotic Cell Death ◽  
Cycle Arrest

p53 is one of the most studied tumor suppressors in the cancer research field. Of note, over 50% of human tumors carry loss of function mutations, and thus p53 has been considered to be a classical Knudson-type tumor suppressor. From the functional point of view, p53 is a nuclear transcription factor to transactivate a variety of its target genes implicated in the induction of cell cycle arrest, DNA repair, and apoptotic cell death. In response to cellular stresses such as DNA damage, p53 is activated and promotes cell cycle arrest followed by the replacement of DNA lesions and/or apoptotic cell death. Therefore, p53 is able to maintain the genomic integrity to prevent the accumulation of genetic alterations, and thus stands at a crossroad between cell survival and cell death. In this paper, we describe a variety of molecular mechanisms behind the regulation of p53.

scholarly journals A C21-Steroidal Glycoside Isolated from the Roots ofCynanchum auriculatumInduces Cell Cycle Arrest and Apoptosis in Human Gastric Cancer SGC-7901 Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yi-Qi Wang ◽  
Shui-Juan Zhang ◽  
Hong Lu ◽  
Bo Yang ◽  
Liang-Fei Ye ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Cycle ◽  
Cell Growth ◽  
Cell Cycle Arrest ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Phase Cell ◽  
Human Gastric Cancer ◽  
Gastric Cancer Cells ◽  
Cycle Arrest

Caudatin 3-O-β-D-cymaropyranosyl-(1→4)-β-D-oleandropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-β-D-cymaropyranoside (CGII) is one of the C21-steroidal glycosides isolated from the roots ofCynanchum auriculatumROYLE ex WIGHT. This study aimed to determine the cell growth, cell proliferation, and apoptotic cell death of human gastric cancer cells after CGII treatment. MTT assay was used to determine cell growth; fluorescence-activated cell sorting analysis was used to evaluate cell cycle distribution and apoptotic cell death. Immunoblotting was applied for measuring the expression of proteins involved in the cell cycle progression. The activities of caspase-3, -8, and -9 were detected by colorimetric caspase activity assays. CGII inhibited cell growth of human gastric cancer SGC-7901 cells in a concentration- and time-dependent manner. Treatment of SGC-7901 cells with CGII resulted in G1 phase cell cycle arrest, accompanied with decreased expression of cyclin D1 and cyclin-dependent kinases 4 and 6. CGII induced cell apoptosis and activated caspase-3, caspase-8, and caspase-9. In contrast, pan-caspase inhibitor z-VAD-fmk partially abolished the CGII-induced growth inhibition of SGC-7901 cells. In conclusion, CGII inhibits cell growth of human gastric cancer cells by inducing G1 phase cell cycle arrest and caspase-dependent apoptosis cascades.

scholarly journals MDM4 Isoform Expression in Melanoma Supports an Oncogenic Role for MDM4-A

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Abdullah Alatawi ◽  
SoonJye Kho ◽  
Michael P. Markey
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
P53 Gene ◽  
Genomic Databases ◽  
P53 Tumor Suppressor ◽  
Cycle Arrest ◽  
Biopsy Specimens ◽  
Direct Mutation

The p53 tumor suppressor integrates upstream signals such as DNA damage and active oncogenes to initiate cell cycle arrest or apoptosis. This response is critical to halting inappropriate growth signals. As such, p53 activity is lost in cancer. In melanoma, however, the p53 gene is intact in a reported 94% of human cases. Rather than direct mutation, p53 is held inactive through interaction with inhibitory proteins. Here, we examine the expression of the two primary inhibitors of p53, MDM2 and MDM4, in genomic databases and biopsy specimens. We find that MDM4 is frequently overexpressed. Moreover, changes in splicing of MDM4 occur frequently and early in melanomagenesis. These changes in splicing must be considered in the design of therapeutic inhibitors of the MDM2/4 proteins for melanoma.

scholarly journals Phenethyl Isothiocyanate (PEITC) Inhibits the Growth of Human Oral Squamous Carcinoma HSC-3 Cells throughG0/G1Phase Arrest and Mitochondria-Mediated Apoptotic Cell Death

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Po-Yuan Chen ◽  
Kai-Chun Lin ◽  
Jing-Pin Lin ◽  
Nou-Ying Tang ◽  
Jai-Sing Yang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cell Cycle Arrest ◽  
Apoptotic Cell ◽  
Human Cancer ◽  
Morphological Changes ◽  
Squamous Carcinoma ◽  
Phenethyl Isothiocyanate ◽  
Cycle Arrest ◽  
Oral Squamous Carcinoma

Phenethyl isothiocyanate (PEITC), an effective anticancer and chemopreventive agent, has been reported to inhibit cancer cell growth through cell-cycle arrest and induction of apoptotic events in various human cancer cells models. However, whether PEITC inhibits human oral squamous cell carcinoma HSC-3 cell growth and its underlying mechanisms is still not well elucidated. In the present study, we evaluated the inhibitory effects of PEITC in HSC-3 cells and examined PEITC-modulated cell-cycle arrest and apoptosis. The contrast-phase and flow cytometric assays were used for examining cell morphological changes and viability, respectively. The changes of cell-cycle and apoptosis-associated protein levels were determined utilizing Western blotting in HSC-3 cells after exposure to PEITC. Our results indicated that PEITC effectively inhibited the HSC-3 cells’ growth and caused apoptosis. PEITC inducedG0/G1phase arrest through the effects of associated protein such as p53, p21, p17, CDK2 and cyclin E, and it triggered apoptosis through promotion of Bax and Bid expression and reduction of Bcl-2, leading to decrease the levels of mitochondrial membrane potential (ΔΨm), and followed the releases of cytochromec, AIF and Endo G then for causing apoptosis in HSC-3 cells. These results suggest that PEITC could be an antitumor compound for oral cancer therapy.

Jab1-siRNA Induces Cell Growth Inhibition and Cell Cycle Arrest in Gall Bladder Cancer Cells via Targeting Jab1 Signalosome

2020 ◽  
Vol 19 (16) ◽  
pp. 2019-2033 ◽  
Author(s):  
Pratibha Pandey ◽  
Mohammad H. Siddiqui ◽  
Anu Behari ◽  
Vinay K. Kapoor ◽  
Kumudesh Mishra ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bladder Cancer ◽  
Cell Growth ◽  
Gall Bladder ◽  
Growth Inhibition ◽  
Cell Cycle Arrest ◽  
Gall Bladder Cancer ◽  
Cell Growth Inhibition ◽  
Cycle Arrest ◽  
Apoptotic Induction

Background: The aberrant alteration in Jab1 signalosome (COP9 Signalosome Complex Subunit 5) has been proven to be associated with the progression of several carcinomas. However the specific role and mechanism of action of Jab1 signalosome in carcinogenesis of gall bladder cancer (GBC) are poorly understood. Objective: The main objective of our study was to elucidate the role and mechanism of Jab1 signalosome in gall bladder cancer by employing siRNA. Methods: Jab1 overexpression was identified in gall bladder cancer tissue sample. The role of Jab1-siRNA approach in cell growth inhibition and apoptotic induction was then examined by RT-PCR, Western Blotting, MTT, ROS, Hoechst and FITC/Annexin-V staining. Results: In the current study, we have shown that overexpression of Jab1 stimulated the proliferation of GBC cells; whereas downregulation of Jab1 by using Jab1-siRNA approach resulted incell growth inhibition and apoptotic induction. Furthermore, we found that downregulation of Jab1 induces cell cycle arrest at G1 phase and upregulated the expression of p27, p53 and Bax gene. Moreover, Jab1-siRNA induces apoptosis by enhancing ROS generation and caspase-3 activation. In addition, combined treatment with Jab1-siRNA and gemicitabine demonstrated an enhanced decline in cell proliferation which further suggested increased efficacy of gemcitabine at a very lower dose (5μM) in combination with Jab1-siRNA. Conclusion: In conclusion, our study strongly suggests that targeting Jab1 signalosome could be a promising therapeutic target for the treatment of gall bladder cancer.

scholarly journals Transcriptional CDK inhibitors, CYC065 and THZ1 promote Bim-dependent apoptosis in primary and recurrent GBM through cell cycle arrest and Mcl-1 downregulation

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Viktorija Juric ◽  
Lance Hudson ◽  
Joanna Fay ◽  
Cathy E. Richards ◽  
Hanne Jahns ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Cell Cycle Arrest ◽  
Cortical Neurons ◽  
Apoptotic Cell ◽  
Cdk Inhibitors ◽  
Induce Cell Death ◽  
Viability Loss ◽  
Cycle Arrest ◽  
Recurrent Gbm

AbstractActivation of cyclin-dependent kinases (CDKs) contributes to the uncontrolled proliferation of tumour cells. Genomic alterations that lead to the constitutive activation or overexpression of CDKs can support tumourigenesis including glioblastoma (GBM), the most common and aggressive primary brain tumour in adults. The incurability of GBM highlights the need to discover novel and more effective treatment options. Since CDKs 2, 7 and 9 were found to be overexpressed in GBM, we tested the therapeutic efficacy of two CDK inhibitors (CKIs) (CYC065 and THZ1) in a heterogeneous panel of GBM patient-derived cell lines (PDCLs) cultured as gliomaspheres, as preclinically relevant models. CYC065 and THZ1 treatments suppressed invasion and induced viability loss in the majority of gliomaspheres, irrespective of the mutational background of the GBM cases, but spared primary cortical neurons. Viability loss arose from G2/M cell cycle arrest following treatment and subsequent induction of apoptotic cell death. Treatment efficacies and treatment durations required to induce cell death were associated with proliferation velocities, and apoptosis induction correlated with complete abolishment of Mcl-1 expression, a cell cycle-regulated antiapoptotic Bcl-2 family member. GBM models generally appeared highly dependent on Mcl-1 expression for cell survival, as demonstrated by pharmacological Mcl-1 inhibition or depletion of Mcl-1 expression. Further analyses identified CKI-induced Mcl-1 loss as a prerequisite to establish conditions at which the BH3-only protein Bim can efficiently induce apoptosis, with cellular Bim amounts strongly correlating with treatment efficacy. CKIs reduced proliferation and promoted apoptosis also in chick embryo xenograft models of primary and recurrent GBM. Collectively, these studies highlight the potential of these novel CKIs to suppress growth and induce cell death of patient-derived GBM cultures in vitro and in vivo, warranting further clinical investigation.

scholarly journals Tumor Suppressor Inactivation in the Pathogenesis of Adult T-Cell Leukemia

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Christophe Nicot
Keyword(s):  
Cell Cycle ◽  
T Cell ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Tumor Suppressors ◽  
Epigenetic Mechanisms ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia ◽  
Cycle Arrest

Tumor suppressor functions are essential to control cellular proliferation, to activate the apoptosis or senescence pathway to eliminate unwanted cells, to link DNA damage signals to cell cycle arrest checkpoints, to activate appropriate DNA repair pathways, and to prevent the loss of adhesion to inhibit initiation of metastases. Therefore, tumor suppressor genes are indispensable to maintaining genetic and genomic integrity. Consequently, inactivation of tumor suppressors by somatic mutations or epigenetic mechanisms is frequently associated with tumor initiation and development. In contrast, reactivation of tumor suppressor functions can effectively reverse the transformed phenotype and lead to cell cycle arrest or death of cancerous cells and be used as a therapeutic strategy. Adult T-cell leukemia/lymphoma (ATLL) is an aggressive lymphoproliferative disease associated with infection of CD4 T cells by the Human T-cell Leukemia Virus Type 1 (HTLV-I). HTLV-I-associated T-cell transformation is the result of a multistep oncogenic process in which the virus initially induces chronic T-cell proliferation and alters cellular pathways resulting in the accumulation of genetic defects and the deregulated growth of virally infected cells. This review will focus on the current knowledge of the genetic and epigenetic mechanisms regulating the inactivation of tumor suppressors in the pathogenesis of HTLV-I.

Sign in / Sign up

Export Citation Format

Share Document