Cyclin D1 Oncogene Research Articles

The targeting of the cyclin D1 oncogene by an Epstein-Barr virus promoter in transgenic mice causes dysplasia in the tongue, esophagus and forestomach.

Cyclin D1 in cooperation with its major catalytic partners, cyclin-dependent kinases cdk4 and cdk6, facilitates progression through the G1 phase of the eukaryotic cell cycle, in part through phosphorylation of the retinoblastoma protein. Cyclin D1's oncogenic properties have been suggested by its cooperation with ras or adenovirus E1a to transform cultured cells, as well its overexpression in transgenic mice that leads to breast cancer. Activated by a number of different mechanisms in human cancers, the cyclin D1 gene is frequently amplified in squamous epithelial cancers derived from the head/neck and esophageal regions. In order to study the functional consequences of cyclin D1 overexpression in these squamous epithelial specific sites, we have linked the Epstein-Barr virus ED-L2 promoter to the human cyclin D1 cDNA and utilized this transgene to generate founder lines. This transgene is transcribed specifically in the tongue, esophagus and forestomach, all sharing a stratified squamous epithelium. The transgene protein product localizes to the basal and suprabasal compartments of these squamous epithelial tissues, and mice from different lines develop dysplasia, a prominent precursor to carcinoma, by 16 months of age in contrast to age-matched wild-type mice. This transgenic model is useful in demonstrating cyclin D1 may be a tumor initiating event in aero-upper digestive squamous epithelial tissues.

Correlation between p53 mutation and cyclin D1 amplification in head and neck squamous cell carcinoma

Mutations in the p53 tumour suppressor gene and amplification of the cyclin D1 (CCND1) oncogene have been commonly reported in various malignancies. In the present study of 39 squamous cell carcinomas of the head and neck, p53 mutations were manifest in 11 (28%) of the cases, whereas CCND1 amplification was seen in 6 (16%) of 37 analysed tumours. The 10 mutations occurring in coding sequences of p53 were found in exon 5 (4 cases), exon 6 (3 cases),f and exon 8 (3 cases). No mutation was found in exon 7. Eight of the 10 exon nucleotide substitutions were missense mutations and two were nonsense mutations. All six tumours with CCND1 amplification also had p53 mutations, while an additional five tumours manifested p53 mutations in the absence of CCND1 amplification. There was a statistically significant positive correlation between these two gene alterations. This raises the possibility that mutation of p53 precedes CCND1 amplification in carcinogenesis.

Inhibition of cyclin D1 oncogene with intracellular single chain antibodies : Marie-Alix Poul, Catherine Teyssier, Marie-Paule Lefranc, Immuogénétique Moléculaire, CNRS-Université de Montpellier II, BP 5051, France

Inhibition of cyclin D1 oncogene with intracellular single chain antibodies : Marie-Alix Poul, Catherine Teyssier, Marie-Paule Lefranc, Immuogénétique Moléculaire, CNRS-Université de Montpellier II, BP 5051, France

Cyclin D1/PRAD1 expression in parathyroid adenomas: an immunohistochemical study.

The cyclin D1 (PRAD1) oncogene is rearranged with the PTH gene and is transcriptionally activated in a subset of parathyroid adenomas. Because of heterogeneity in rearrangement breakpoints, the true percentage of adenomas with cyclin D1 deregulation is unknown. Overexpression of the cyclin D1 protein in parathyroid adenomas appears to be a unifying consequence of all cyclin D1 gene rearrangements and can, therefore, be examined to more comprehensively identify adenomas in which cyclin D1 is pathogenetically important. We studied cyclin D1 expression in 65 parathyroid adenomas (from 64 patients), 51 normal parathyroid glands (from the same patients), and 4 parathyroid carcinoma specimens (from 3 patients) using a microwave-enhanced immunohistochemical method and affinity-purified cyclin D1 polyclonal antiserum. When available, data on adenoma mass, intact PTH level, and concurrent serum calcium level were also collected. Twelve of the 65 adenomas (18%) showed diffuse nuclear staining of approximately 30-70% of the tumor cells. All 51 normal glands were negative, except 1 gland that showed scattered cells ( < 10%) with positive nuclear staining. In addition, scattered positive cells were seen in the compressed rim of histologically normal parathyroid tissue surrounding 2 adenomas that were cyclin D1 negative. No significant differences in adenoma mass, intact PTH levels, or concurrent calcium levels were found between positive and negative tumors. Two of 4 parathyroid carcinoma specimens from 2 of 3 patients showed strong nuclear staining for cyclin D1. Overexpression of the cyclin D1 oncogene in 18% of our cases, due to the cyclin D1/PTH translocation and/or other mechanisms, suggests that overexpressed cyclin D1 plays a role in the pathogenesis of a much larger proportion of parathyroid adenomas than previously appreciated. Cyclin D1 overexpression is a feature of typical parathyroid adenomas and is not confined to unusually large, symptom-causing adenomas as had been suggested by early DNA studies. Although only three patients with parathyroid carcinoma were studied, two of the patients' tumors stained for cyclin D1, raising the possibility that the frequency of cyclin D1 overexpression may be even greater in carcinomas. Cyclin D1 overexpression appears to highlight a central pathway in parathyroid neoplasia.

Human cyclin D1 oncogene and esophageal squamous cell carcinoma.

Oncogene activation and tumor suppressor gene inactivation have been implicated in the genetic basis of esophageal squamous cell carcinoma (ESCC). Cyclin D1, an oncogene that has a critical role in G1 progression of the cell cycle, has been observed to be amplified in carcinomas of the breast and head and neck, and translocated in parathyroid adenomas and centrocytic lymphomas. Established ESCC cell lines were assayed for cyclin D1 amplification and overexpression by Southern, Northern, and Western blot analyses. In addition, cyclin D1 overexpression was determined in primary tumors and adjacent normal mucosa by differential polymerase chain reaction (PCR) and immunohistochemical staining. The authors observed that approximately 50% of ESCC cell lines with cyclin D1 DNA amplification also had RNA and protein overexpression. Related genes, cyclin D2 and D3, were not amplified or overexpressed in these cell lines with rare exception. The cyclin D1 protein was able to associate with the cell-cycle-dependent kinases, cdk4 and cdk6, but not always with proliferating cell nuclear antigen in selected cell lines tested, representing a novel finding. In addition, approximately 50% of primary tumors had cyclin D1 overexpression that was not present in adjacent normal mucosa. Cyclin D1 overexpression based on PCR correlated with enhanced cyclin D1 protein nuclear staining in malignant cells. Cyclin D1 is amplified and overexpressed in ESCC and may be important in its molecular pathogenesis.

Esophageal squamous epithelial cyclin D1 oncogene expression using an epstein-barr virus promoter in transgenic mice: H. Nakagawa 1, TC Wang 1, K Togawa 1, L Zukerberg 2, R Odze 3, JB Wilson 4, [formula omitted]1, 1Gastrointestinal Unit and 2Pathology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, 3Department of Pathology, Brigham & Women's Hospital, Boston, Mass. and 4Ludwig Institute

Esophageal squamous epithelial cyclin D1 oncogene expression using an epstein-barr virus promoter in transgenic mice: H. Nakagawa 1, TC Wang 1, K Togawa 1, L Zukerberg 2, R Odze 3, JB Wilson 4, [formula omitted]1, 1Gastrointestinal Unit and 2Pathology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, 3Department of Pathology, Brigham & Women's Hospital, Boston, Mass. and 4Ludwig Institute

EXPRESSION OF CYCLIN D1 IN SQUAMOUS-CELL CARCINOMAS OF THE HEAD AND NECK

Expression of oncogenes Cyclin D1, FGF-3 and FGF-4 was investigated in eight cases of squamous cell carcinoma of the head and neck (SCCHN) and matched normal controls using the sensitive detection technique of RT-PCR. We demonstrate elevated expression of cyclin D1 in 5/8 SCCHN tumor samples and describe the first report of overexpression of cyclin D1 in tumors of the pyriform sinus. In contrast, we do not detect, under routine conditions, expression of oncogenes FGF-3 and FGF-4 in these tumors and suggest that FGF-3 and FGF-4 are unlikely to play a role in the development of squamous cell carcinomas of the head and neck.

The PRAD-1/cyclin D1 oncogene product accumulates aberrantly in a subset of colorectal carcinomas.

The PRAD-1/cyclin D1 proto-oncogene is localized on chromosome 11q13 and it is overexpressed in several tumour types as a consequence of gene amplification or chromosomal rearrangements. In this study, the abundance and patterns of cyclin D1 protein expression in normal/non-involved colon (n = 44), primary (n = 48) and metastatic (n = 9) colorectal carcinomas, and in a series of 4 colon cancer cell lines were investigated by immunochemical methods using the DCS-6 monoclonal antibody specific for cyclin D1. While examination of all normal colorectal tissue samples and 56% of the primary tumours revealed only weak to undetectable immunostaining signals, 23% of the primary carcinomas showed moderate and 21% showed strong aberrant accumulation of this cell-cycle regulatory oncoprotein. The immunohistochemical patterns in the secondary lesions were concordant with the matched primary tumours in all cases. The staining was nuclear both in the clinical specimens and in the colon cancer cell lines, in which the antibody-mediated knock-out experiments demonstrated a positive regulatory role of the cyclin D1 protein whose function was required for progression through the G1 phase of the cell cycle. These results indicate that the PRAD-1/cyclin D1 protooncogene may be deregulated in a significant subset of colorectal tumours, and warrant further analyses of such aberrations of the cyclin D1/retinoblastoma protein pathway to elucidate its potential involvement in the multistep pathogenesis of human colorectal cancer.

PRAD-1 (CCND1)/Cyclin D1 oncogene amplification in primary head and neck squamous cell carcinoma

Abnormalities in chromosome 11q13 regions have been frequently found in head and neck squamous carcinoma. Recent studies indicate that the PRAD-1 (also CCND1), which encodes cyclin D1, is a putative oncogene that is an important component of this region. DNA was extracted from 32 snap-frozen specimens from primary head and neck squamous carcinomas. DNA from peripheral blood lymphocytes, normal mucosa, and salivary gland tissue were used as controls. A genomic DNA probe containing the first exon of PRAD-1 was used for hybridization with specimen DNAs by the Southern technique. A 5.6-kb genomic DNA probe of immunoglobulin heavy chain was used as an internal standard for assessing PRAD-1 amplification. Eleven (34.4%) squamous carcinoma specimens showed PRAD-1 amplification (2- to 10-fold). Although no significant statistical correlation among amplification status, grade stage, and DNA ploidy was observed in this small cohort, amplification was more noted in high grade, high stage, and aneuploid tumors. A highly statistical correlation between PRAD-1 amplification and proliferative activity was noted (P > 0.001). The results of this study indicate that PRAD-1 amplification appears to be a late event in the tumorigenesis of head and neck carcinoma and is associated often with a subset of aggressive tumors and high proliferation neoplasms.

DNA tumor virus oncoproteins and retinoblastoma gene mutations share the ability to relieve the cell's requirement for cyclin D1 function in G1.

The retinoblastoma gene product (pRB) participates in the regulation of the cell division cycle through complex formation with numerous cellular regulatory proteins including the potentially oncogenic cyclin D1. Extending the current view of the emerging functional interplay between pRB and D-type cyclins, we now report that cyclin D1 expression is positively regulated by pRB. Cyclin D1 mRNA and protein is specifically downregulated in cells expressing SV40 large T antigen, adenovirus E1A, and papillomavirus E7/E6 oncogene products and this effect requires intact RB-binding, CR2 domain of E1A. Exceptionally low expression of cyclin D1 is also seen in genetically RB-deficient cell lines, in which ectopically expressed wild-type pRB results in specific induction of this G1 cyclin. At the functional level, antibody-mediated cyclin D1 knockout experiments demonstrate that the cyclin D1 protein, normally required for G1 progression, is dispensable for passage through the cell cycle in cell lines whose pRB is inactivated through complex formation with T antigen, E1A, or E7 oncoproteins as well as in cells which have suffered loss-of-function mutations of the RB gene. The requirement for cyclin D1 function is not regained upon experimental elevation of cyclin D1 expression in cells with mutant RB, while reintroduction of wild-type RB into RB-deficient cells leads to restoration of the cyclin D1 checkpoint. These results strongly suggest that pRB serves as a major target of cyclin D1 whose cell cycle regulatory function becomes dispensable in cells lacking functional RB. Based on available data including this study, we propose a model for an autoregulatory feedback loop mechanism that regulates both the expression of the cyclin D1 gene and the activity of pRB, thereby contributing to a G1 phase checkpoint control in cycling mammalian cells.

RAWP revisited

Parathyroid carcinoma (PC) is an uncommon finding, accounting for only 1-2% of patients with primary hyperparathyroidism (HPT), but a relatively higher incidence has been reported in Italy and Japan. The etiology of the tumour remains unclear, but molecular analysis studies have hypothesised the involvement of mutations of several genes in the pathogenesis of PC, including the oncogene cyclin D1 or PRAD1 located at the chromosome 13, the retinoblastoma and the p53 tumour suppressor gene. The clinical presentation of patients with PC is mainly related to the increased secretion of PTH rather than to the tumour burden. The pre-operative diagnosis of malignancy is very difficult to obtain, and, thus, intra-operative recognition of PC is mandatory. However, reliable signs of malignancy are rarely detectable. Probably, only vascular invasion, that correlates with tumour recurrence and metastases, should be considered useful in confirming malignancy, although both Ki-67 and Cyclin D1 have been recently used to aid in the definitive diagnosis. The en bloc resection of the tumour, together with ipsilateral thyroid lobe and adjacent structures, only if involved, avoiding any capsular rupture of the mass, represents the gold standard of surgical treatment of patients. Although the PC has traditionally been considered as a radioresistant tumour, there are some retrospective data holding a possible benefit from post-operative irradiation. No cytotoxic regimen with proven efficacy is currently available for patients with PC, but since hypercalcemia is ultimately the most frequent cause of death, several studies have suggested the usefulness of bisphosphonates (i.e., clodronate, pamidronate and zoledronate), calcitonin, and calcimimetic agents (i.e., cinacalcet) in patients with PC and severe hypercalcemia. In conclusion, PC is a rare malignancy and the NCDB survey reports an overall five- and ten-year survival rate of 85% and 49%, respectively. However, it is very difficult to predict the clinical behaviour of patients with PC and probably the ultimate prognosis depends on successful resection of the tumour at the initial surgery.