Iron chelation regulates cyclin D1 expression via the proteasome: a link to iron deficiency–mediated growth suppression

Blood ◽  
2006 ◽  
Vol 109 (9) ◽  
pp. 4045-4054 ◽  
Author(s):  
Effie Nurtjahja-Tjendraputra ◽  
Dong Fu ◽  
Juanita M. Phang ◽  
Des R. Richardson
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Control ◽  
D1 Protein ◽  
Iron Chelation ◽  
Growth Suppression ◽  
Dependent Manner ◽  
Critical Function ◽  
Cyclin D1 Protein

Abstract Iron (Fe) plays an important role in proliferation, and Fe deficiency results in G1/S arrest. Despite this, the precise role of Fe in cell-cycle control remains unclear. Cyclin D1 plays a critical function in G1 progression by interacting with cyclin-dependent kinases. Previously, we examined the effect of Fe depletion on the expression of cell-cycle control molecules and identified a marked decrease in cyclin D1 protein, although the mechanism involved was unknown. In this study, we showed that cyclin D1 was regulated posttranscriptionally by Fe depletion. Iron chelation of cells in culture using desferrioxamine (DFO) or 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) decreased cyclin D1 protein levels after 14 hours and was rescued by the addition of Fe. Cyclin D1 half-life in control cells was 80 ± 15 minutes (n = 5), while in chelator-treated cells it was significantly (P < .008) decreased to 38 ± 3 minutes (n = 5). Proteasomal inhibitors rescued the Fe chelator–mediated decrease in cyclin D1 protein, suggesting the role of the proteasome. In Fe-replete cells, cyclin D1 was degraded in an ubiquitin-dependent manner, while Fe depletion induced a ubiquitin-independent pathway. This is the first report linking Fe depletion–mediated growth suppression at G1/S to a mechanism inducing cyclin D1 proteolysis.

mTOR function in skeletal muscle hypertrophy: increased ribosomal RNA via cell cycle regulators

2005 ◽  
Vol 289 (6) ◽  
pp. C1457-C1465 ◽  
Author(s):  
Gustavo A. Nader ◽  
Thomas J. McLoughlin ◽  
Karyn A. Esser
Keyword(s):  
Cell Cycle ◽  
Protein Expression ◽  
Cyclin D1 ◽  
Ribosomal Rna ◽  
Molecular Mechanisms ◽  
D1 Protein ◽  
Rna Content ◽  
Cyclin D1 Protein ◽  
Rb Phosphorylation ◽  
Myotube Hypertrophy

The purpose of this study was to identify the potential downstream functions associated with mammalian target of rapamycin (mTOR) signaling during myotube hypertrophy. Terminally differentiated myotubes were serum stimulated for 3, 6, 12, 24, and 48 h. This treatment resulted in significant myotube hypertrophy (protein/DNA) and increased RNA content (RNA/DNA) with no changes in DNA content or indices of cell proliferation. During myotube hypertrophy, the increase in RNA content was accompanied by an increase in tumor suppressor protein retinoblastoma (Rb) phosphorylation and a corresponding increase in the availability of the ribosomal DNA transcription factor upstream binding factor (UBF). Serum stimulation also induced an increase in cyclin D1 protein expression in the differentiated myotubes with a concomitant increase in cyclin D1-dependent cyclin-dependent kinase (CDK)-4 activity toward Rb. The increases in myotube hypertrophy and RNA content were blocked by rapamycin treatment, which also prevented the increase in cyclin D1 protein expression, CDK-4 activity, Rb phosphorylation, and the increase in UBF availability. Our findings demonstrate that activation of mTOR is necessary for myotube hypertrophy and suggest that the role of mTOR is in part to modulate cyclin D1-dependent CDK-4 activity in the regulation of Rb and ribosomal RNA synthesis. On the basis of these results, we propose that common molecular mechanisms contribute to the regulation of myotube hypertrophy and growth during the G1 phase of the cell cycle.

Carcinosarcoma of the Tongue With Cyclin D1 Gene Amplification

2001 ◽  
Vol 125 (3) ◽  
pp. 433-436
Author(s):  
Hiroaki Suzuki ◽  
Katsushige Yamashiro ◽  
Chikako Yoshida ◽  
Yasunori Fujioka
Keyword(s):  
Cell Cycle ◽  
Squamous Cell Carcinoma ◽  
Cyclin D1 ◽  
Spindle Cell ◽  
D1 Protein ◽  
Molecular Aspect ◽  
Sarcomatous Component ◽  
Cyclin D1 Protein ◽  
Rare Malignancy

Abstract Carcinosarcoma of the tongue is a rare malignancy and its molecular aspect is unclear. A case of carcinosarcoma of the tongue in a 51-year-old man is presented. A polypoid tumor of the tongue, measuring 12 × 12 × 6 mm, was resected. Histologically, the tumor was composed of a squamous cell carcinoma and a spindle cell sarcomatous component. We previously showed that one cell-cycle regulator, the cyclin D1 gene, was frequently amplified in esophageal carcinosarcoma, which shows the same morphologic features as carcinosarcoma of the tongue. In this case, we examined whether the cyclin D1 gene is amplified in carcinosarcoma of the tongue as well. Fluorescence in situ hybridization analysis revealed that the cyclin D1 gene was amplified in both components of carcinosarcoma of the tongue. The cyclin D1 protein was also detected by immunostaining in both components. Our results suggest that the amplification of cyclin D1 gene plays a role in the molecular pathogenesis of carcinosarcoma of the tongue, at least in some cases.

Myeloma Cell Lines Are Not Sensitive to Modulation of Cyclin D1 Level.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 790-790 ◽  
Author(s):  
Helen D. Nickerson ◽  
Marta Chesi ◽  
Peter Leif Bergsagel
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Cyclin D1 ◽  
Cell Lines ◽  
Transfection Efficiency ◽  
D1 Protein ◽  
Myeloma Cell ◽  
Transfected Cells ◽  
Cyclin D1 Protein ◽  
Human Myeloma Cell

Abstract Dysregulation of D type cyclins is an almost universal event in multiple myeloma. Overexpression of cyclin D1 may occur by chromosomal translocation of t(11:14)(q13:32), and also in association with hyperdiploidy. To investigate the role of cyclin D1 in the growth of human myeloma cell lines, we used both shRNA plasmid constructs, and an siRNA Smartpool against cyclin D1 and compared to control cells transfected with anti-GFP or GAPDH constructs. siRNA was electroporated into multiple myeloma cell lines overexpressing cyclin D1 (KMS12PE, U266, H929) which gave a 50–60% transfection efficiency, assessed using a GFP plasmid. Successful reduction in levels of cyclin D1 was confirmed by western blotting and normalization to a beta actin standard. Cyclin D1 protein in sh- or siRNA transfected cells was reduced on average to 32% of that in cells transfected with an anti-GAPDH or anti-GFP siRNA. In individual experiments reduction of cyclin D1 protein to as little as 10% of control was observed. However, we found no sign of increased apoptosis by Annexin V/Propidium iodide staining. Furthermore, cell cycle analysis by ethidium bromide staining and flow cytometry revealed no significant change in the cell cycle of sh- or siRNA transfected cells when compared to control cells. qPCR analysis revealed no acute compensatory increase in the RNA levels of other D-type cyclins (D2, D3) following reduction of cyclin D1 levels. These results may be explained by the residual presence of sufficient cyclin D1 protein for cell cycle progression. An alternative explanation is that changes that frequently occur in myeloma to other cell cycle regulators, for example p16(INK4a) and Rb are able to circumvent cell cycle effects of reducing cyclin D1protein. These results suggest that the human myeloma cell lines tested are not acutely sensitive to cyclin D1 level.

scholarly journals Frequent overexpression of cyclin D1 in sporadic pancreatic endocrine tumours

2003 ◽  
Vol 179 (1) ◽  
pp. 73-79 ◽  
Author(s):  
SS Guo ◽  
X Wu ◽  
AT Shimoide ◽  
J Wong ◽  
F Moatamed ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Cyclin D1 ◽  
P38 Mapk ◽  
D1 Protein ◽  
Mitogen Activated Protein Kinase ◽  
Transcriptional Level ◽  
Endocrine Tumours ◽  
Cyclin D1 Protein ◽  
Pancreatic Endocrine Tumours

Pancreatic endocrine tumours (PETs) occur sporadically or are inherited as part of the multiple endocrine neoplasia type-1 syndrome. Little is known about the molecular events leading to these tumours. Cyclin D1, a key regulator of the G1/S transition of the cell cycle, is overexpressed in a variety of human cancers as well as certain endocrine tumours. We hypothesized that similar to other endocrine tumours, cyclin D1 is overexpressed in human sporadic PETs. Cyclin D1 protein overexpression was found in 20 of 31 PETs (65%) when compared with normal pancreatic tIssue. Furthermore, Northern blot analysis suggests that cyclin D1 up-regulation occurs at the post-transcriptional level in some PETs. Because the key cell growth signalling pathways p42/p44/ERK (extracellular signal-regulated kinase), p38/MAPK (mitogen-activated protein kinase), and Akt/PKB (protein kinase B) can regulate cyclin D1 protein expression in other cell types, pancreatic endocrine tumours were analysed with phospho-specific antibodies against the active forms of these proteins to elucidate a tIssue-specific regulatory mechanism of cyclin D1 in PETs. We found frequent activation of the p38/MAPK and Akt pathways, but down-regulation of the ERK pathway, in cyclin D1 overexpressing PETs. This study demonstrates that cyclin D1 overexpression is associated with human sporadic PET tumorigenesis, and suggests that this up-regulation may occur at the post-transcriptional level. These findings will direct future studies of PETs towards cell cycle dysregulation and the identification of key growth factor pathways involved in the formation of these tumours.

scholarly journals P53-dependent suppression of the human calcyclin gene (S100A6): the role of Sp1 and of NFkappaB.

2008 ◽  
Vol 55 (3) ◽  
pp. 559-570 ◽  
Author(s):  
Weronika Króliczak ◽  
Maciej Pietrzak ◽  
Monika Puzianowska-Kuznicka
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Control ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Wild Type ◽  
Lower Efficiency ◽  
Wild Type P53 ◽  
Cell Cycle Deregulation ◽  
Cancer Tissues

Calcyclin (S100A6) is believed to participate in cell cycle control. It was, however, unclear if its expression depends on p53, a key regulator of apoptosis and cell cycle. We therefore performed transcription regulation assays in HeLa cells and found that wild type p53 suppressed the S100A6 promoter up to 12-fold in a dose-dependent manner. In contrast, the well-characterized V143A, R175H, R249S, and L344A p53 mutants cloned from human cancers suppressed this promoter with a 6 to 9-fold lower efficiency. All the sites mediating the p53-dependent suppression were contained in the -167 to +134 fragment of the S100A6 promoter. Separate overexpression of either Sp1 or of NFkappaB only partially counteracted the p53 inhibitory effect on the S100A6 promoter, while simultaneous overexpression of both these transactivators resulted in a complete abolishment of the p53 inhibitory effect on this promoter. Sp1 and NFkappaB binding to the probes resembling their putative binding sites present in the S100A6 promoter was decreased in the presence of wild type p53. We propose that the suppression of S100A6 is yet another mechanism by which p53 inhibits proliferation. Insufficient suppression of this gene by p53 mutants could well be responsible for calcyclin overexpression and cell cycle deregulation observed in cancer tissues.

scholarly journals Metformin Inhibits Growth of Breast Cancer Cell T47 through Decreasing Expression of Protein P53, BCL2 and Cyclin D1

2019 ◽  
pp. e000164
Author(s):  
Irma Yanti Rangkuti ◽  
Poppy Anjelisa Zaitun Hasibuan ◽  
Tri Widyawati ◽  
Yahwardiah Siregar
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Protein Expression ◽  
Cyclin D1 ◽  
P53 Protein ◽  
D1 Protein ◽  
T47d Cell ◽  
G1 Phase ◽  
T47d Cells ◽  
Cyclin D1 Protein

Breast cancer is a disease that afflicts women only 0.5 to 1 % are male breast cancers.Breast cancer has several variants and requires a different therapeutic approach, and until now the therapy has not been satisfactory due to the emergence of resistance. Metformin as the main choice drug type 2 diabetes mellitus which is known to have a cytotoxic effect for breast cancer. This study aimed to analyze metformin cytotoxic mechanisms covering the cell cycle , apoptosis, expression of p53, bcl-2 and cyclin D1 T47D cells which exposed to metformin HCl. The study was conducted invitro on T47D breast cancer cells which exposed to metformin concentrations of 1738.2 µg / mL and 3476.4 µg / mL and doxorubicin concentrations of 0.1µg / mL and 0.2µg / mL for 24 hours. Cell cycle testing and apoptosis using the flowsitometry method and expression test of p53 protein, bcl-2 dancycline D1 in T47D cells with immunocytochemistry. Data was analyzed by one way Anova with Bonferroni's advanced test. The results showed that metformin inhibited the G0-G1 phase of the T47D cell cycle, triggered T47D cell apoptosis, significantly reduced p53, bcl-2 and cyclin D1 protein expression (p <0.05). Conclusion of the study, metformin inhibits T47D cells through inhibition of the cell cycle G0-G1 phase, reducing protein expression p53, bcl-2 and cyclin D1.

Resistance to Bortezomib Develops Slowly in MCL Cells, Extends to the Class of Proteasome Inhibitors, and Is Associated with Decreased Proliferation of the Resistant Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4397-4397 ◽  
Author(s):  
Helena Mora-Jensen ◽  
Edgar G. Rizzatti ◽  
Adrian Wiestner
Keyword(s):  
Cell Cycle ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Protein Expression ◽  
Cell Cycle Control ◽  
Proteasome Inhibitors ◽  
D1 Protein ◽  
Hsp70 Protein ◽  
Cyclin D1 Protein ◽  
Shock Proteins

Abstract Mantle Cell Lymphoma (MCL) is a malignancy of mature B-cells. MCL has a poor prognosis and a limited response to traditional chemotherapy. Bortezomib (BZM), a new powerful inhibitor of the proteasome, can induce responses in up to 50% of relapsed MCL patients, suggesting that in at least half of the patients the lymphoma cells are intrinsically resistant to BZM or rapidly develop resistance during single agent therapy. To investigate possible mechanisms of BZM resistance, we cultured MCL cell lines continuously in sub-lethal concentrations of BZM that were then gradually increased. Resistance was slow to develop taking several months for truly resistant clones to grow out. We generated a bortezomib resistant (BR) clone of HBL-2 with an IC50 of 30nM compared to 5nM in the parental clone and several BR subclones of Jeko-1, the most resistant of which had an IC50 of 200nM compared to 3nM for the parental clone. All BR subclones also showed decreased sensitivity to three other proteasome inhibitors: MG-132, Lactacystin, and NLVS. The increase in IC50 to these drugs was between 3 and 8-fold, consistent with more off-target effects of these drugs compared to BZM. BAY11-7082, an inhibitor of NF-kB signaling, maintained its activity against the resistant cells. Resistance to BZM, once acquired, has remained stable over several months. This is remarkable because the resistant subclones grow significantly slower than the parental lines, even after having been removed from selection for extended periods of time. Consistent with slower cell proliferation, we found reduced Cyclin D1 protein expression in the BZM resistant Jeko clones; however, mRNA levels were comparable to the parental line, indicating that changes in Cyclin D1 protein translation and/or stability may be responsible for the decreased proliferation. BZM resistance has been associated with up-regulation of proteasome components and heat-shock proteins. Indeed, in the resistant HBL-2 subclone we found marked upregulation of two proteasome components (PSMA5 and PSMC1) and of Hsp70 by RT-PCR, but there was only a small change in Hsp70 protein expression. Nevertheless, upregulation of these genes could be part a more global gene expression response as seen with ER-stress and could thus reflect an adaptive change to BZM in the HBL-2 BR subclone. All three Jeko BR clones in contradistinction showed only minor changes in PSMA5, PSMC1 and Hsp70 mRNA expression and surprisingly had markedly reduced Hsp70 protein levels. Thus, in these subclones, BR resistance appears to correlate primarily with changes affecting cell cycle control. We conclude that resistance to BZM may be determined by several mechanisms that affect cell cycle control as well as expression of proteasome components and heat-shock proteins. While the slow development of resistance suggests adaptive changes, its persistence over time is more consistent with mutations or other genomic alterations that are not readily reversible. Ongoing studies aim to more precisely define the basis for BZM resistance in MCL.

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