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Ghozlan H, Showalter A, Lee E, Zhu X, Khaled AR. Chaperonin-Containing TCP1 Complex (CCT) Promotes Breast Cancer Growth Through Correlations With Key Cell Cycle Regulators. Front Oncol 2021; 11:663877. [PMID: 33996588 PMCID: PMC8121004 DOI: 10.3389/fonc.2021.663877] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
Uncontrolled proliferation as a result of dysregulated cell cycling is one of the hallmarks of cancer. Therapeutically targeting pathways that control the cell cycle would improve patient outcomes. However, the development of drug resistance and a limited number of inhibitors that target multiple cell cycle modulators are challenges that impede stopping the deregulated growth that leads to malignancy. To advance the discovery of new druggable targets for cell cycle inhibition, we investigated the role of Chaperonin-Containing TCP1 (CCT or TRiC) in breast cancer cells. CCT, a type II chaperonin, is a multi-subunit protein-folding complex that interacts with many oncoproteins and mutant tumor suppressors. CCT subunits are highly expressed in a number of cancers, including breast cancer. We found that expression of one of the CCT subunits, CCT2, inversely correlates with breast cancer patient survival and is subject to copy number alterations through genomic amplification. To investigate a role for CCT2 in the regulation of the cell cycle, we expressed an exogenous CCT2-FLAG construct in T47D and MCF7 luminal A breast cancer cells and examined cell proliferation under conditions of two-dimensional (2D) monolayer and three-dimensional (3D) spheroid cultures. Exogenous CCT2 increased the proliferation of cancer cells, resulting in larger and multiple spheroids as compared to control cells. CCT2-expressing cells were also able to undergo spheroid growth reversal, re-attaching, and resuming growth in 2D cultures. Such cells gained anchorage-independent growth. CCT2 expression in cells correlated with increased expression of MYC, especially in spheroid cultures, and other cell cycle regulators like CCND1 and CDK2, indicative of a novel activity that could contribute to the increase in cell growth. Statistically significant correlations between CCT2, MYC, and CCND1 were shown. Since CCT2 is located on chromosome 12q15, an amplicon frequently found in soft tissue cancers as well as breast cancer, CCT2 may have the basic characteristics of an oncogene. Our findings suggest that CCT2 could be an essential driver of cell division that may be a node through which pathways involving MYC, cyclin D1 and other proliferative factors could converge. Hence the therapeutic inhibition of CCT2 may have the potential to achieve multi-target inhibition, overcoming the limitations associated with single agent inhibitors.
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Affiliation(s)
- Heba Ghozlan
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Adrian Showalter
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Eunkyung Lee
- Department of Health Sciences, College of Health Professions and Sciences, University of Central Florida, Orlando, FL, United States
| | - Xiang Zhu
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Annette R Khaled
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
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Kinase-independent role of cyclin D1 in chromosomal instability and mammary tumorigenesis. Oncotarget 2016; 6:8525-38. [PMID: 25940700 PMCID: PMC4496164 DOI: 10.18632/oncotarget.3267] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 01/31/2015] [Indexed: 01/26/2023] Open
Abstract
Cyclin D1 is an important molecular driver of human breast cancer but better understanding of its oncogenic mechanisms is needed, especially to enhance efforts in targeted therapeutics. Currently, pharmaceutical initiatives to inhibit cyclin D1 are focused on the catalytic component since the transforming capacity is thought to reside in the cyclin D1/CDK activity. We initiated the following study to directly test the oncogenic potential of catalytically inactive cyclin D1 in an in vivo mouse model that is relevant to breast cancer. Herein, transduction of cyclin D1−/− mouse embryonic fibroblasts (MEFs) with the kinase dead KE mutant of cyclin D1 led to aneuploidy, abnormalities in mitotic spindle formation, autosome amplification, and chromosomal instability (CIN) by gene expression profiling. Acute transgenic expression of either cyclin D1WT or cyclin D1KE in the mammary gland was sufficient to induce a high CIN score within 7 days. Sustained expression of cyclin D1KE induced mammary adenocarcinoma with similar kinetics to that of the wild-type cyclin D1. ChIP-Seq studies demonstrated recruitment of cyclin D1WT and cyclin D1KE to the genes governing CIN. We conclude that the CDK-activating function of cyclin D1 is not necessary to induce either chromosomal instability or mammary tumorigenesis.
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Witkiewicz AK, Knudsen ES. Retinoblastoma tumor suppressor pathway in breast cancer: prognosis, precision medicine, and therapeutic interventions. Breast Cancer Res 2014; 16:207. [PMID: 25223380 PMCID: PMC4076637 DOI: 10.1186/bcr3652] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A series of recent studies have demonstrated that the retinoblastoma tumor suppressor (RB) pathway plays a critical role in multiple clinically relevant aspects of breast cancer biology, spanning early stage lesions to targeted treatment of metastatic disease. In ductal carcinoma in situ, multiple groups have shown that dysregulation of the RB pathway is critically associated with recurrence and disease progression. Functional models have similarly illustrated key roles for RB in regulating epithelial–mesenchymal transition and other features contributing to aggressive disease. Invasive breast cancers are treated in distinct fashions, and heterogeneity within the RB pathway relates to prognosis and response to commonly used therapeutics. Luminal B breast cancers that have a poor prognosis amongst estrogen receptor-positive disease are defined based on the expression of RB-regulated genes. Such findings have led to clinical interventions that directly target the RB pathway through CDK4/6 inhibition which have promise in both estrogen receptor-positive and Her2-positive disease. In contrast, RB loss results in improved response to chemotherapy in triple-negative breast cancer, where ongoing research is attempting to define intrinsic vulnerabilities for targeted intervention. These findings support a wide-reaching impact of the RB pathway on disease that could be harnessed for improved clinical interventions.
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Lou X, Zhang J, Liu S, Xu N, Liao DJ. The other side of the coin: the tumor-suppressive aspect of oncogenes and the oncogenic aspect of tumor-suppressive genes, such as those along the CCND-CDK4/6-RB axis. Cell Cycle 2014; 13:1677-93. [PMID: 24799665 DOI: 10.4161/cc.29082] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although cancer-regulatory genes are dichotomized to oncogenes and tumor-suppressor gene s, in reality they can be oncogenic in one situation but tumor-suppressive in another. This dual-function nature, which sometimes hampers our understanding of tumor biology, has several manifestations: (1) Most canonically defined genes have multiple mRNAs, regulatory RNAs, protein isoforms, and posttranslational modifications; (2) Genes may interact at different levels, such as by forming chimeric RNAs or by forming different protein complexes; (3) Increased levels of tumor-suppressive genes in normal cells drive proliferation of cancer progenitor cells in the same organ or tissue by imposing compensatory proliferation pressure, which presents the dual-function nature as a cell-cell interaction. All these manifestations of dual functions can find examples in the genes along the CCND-CDK4/6-RB axis. The dual-function nature also underlies the heterogeneity of cancer cells. Gene-targeting chemotherapies, including that targets CDK4, are effective to some cancer cells but in the meantime may promote growth or progression of some others in the same patient. Redefining "gene" by considering each mRNA, regulatory RNA, protein isoform, and posttranslational modification from the same genomic locus as a "gene" may help in better understanding tumor biology and better selecting targets for different sub-populations of cancer cells in individual patients for personalized therapy.
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Affiliation(s)
- Xiaomin Lou
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Ju Zhang
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Siqi Liu
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Ningzhi Xu
- Laboratory of Cell and Molecular Biology; Cancer Institute; Chinese Academy of Medical Science; Beijing, PR China
| | - D Joshua Liao
- Hormel Institute; University of Minnesota; Austin, MN USA
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Chung J, Noh H, Park KH, Choi E, Han A. Longer survival in patients with breast cancer with cyclin d1 over-expression after tumor recurrence: longer, but occupied with disease. J Breast Cancer 2014; 17:47-53. [PMID: 24744797 PMCID: PMC3988342 DOI: 10.4048/jbc.2014.17.1.47] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 03/13/2014] [Indexed: 11/30/2022] Open
Abstract
Purpose The effect of cyclin D1 overexpression on breast cancer outcomes and prognosis is controversial, even though amplification of the cyclin D1 gene, CCND1, has been shown to be associated with early relapse and poor prognosis. In this study, we examined the relationship between cyclin D1 overexpression and disease-specific survival (DSS). We also analyzed survival in patients who experienced recurrence. Methods We retrospectively analyzed data from patients diagnosed with ductal carcinoma between April 2005 and December 2010. We examined clinicopathologic factors associated with cyclin D1 overexpression and analyzed the influence of cyclin D1 on recurrence-free survival and DSS. Results We identified 236 patients diagnosed with primary breast cancer who completed all phases of their primary treatment. Cyclin D1 overexpression was significantly associated with longer DSS (5-year DSS, 89.9% in patients without cyclin D1 overexpression vs. 98.9% in patients with cyclin D1 overexpression; p=0.008). Multivariate analysis also found that patients with cyclin D1 overexpressing tumors had significantly longer disease-specific survival than patients whose tumors did not overexpress cyclin D1, with a hazard ratio for disease-specific mortality of 7.97 (1.17-54.22, p=0.034). However, in the group of patients who experienced recurrence, cyclin D1 overexpression was not significantly associated with recurrence-free survival. Cyclin D1 overexpression was significantly associated with increased survival after disease recurrence, indicating that cyclin D1 overexpression might be indicative of more indolent disease progression after metastasis. Conclusion Cyclin D1 overexpression is associated with longer DSS, but not recurrence-free survival, in patients with breast cancer. Longer postrecurrence survival could explain the apparent inconsistency between DSS and recurrence-free survival. Patients with cyclin D1-overexpressing tumors survive longer, but with metastatic disease after recurrence. This information should spark the urgent development of tailored therapies to cure these patients.
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Affiliation(s)
- Jaesik Chung
- Department of Surgery, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Hany Noh
- Department of Surgery, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Kwang Hwa Park
- Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Eunhee Choi
- Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Airi Han
- Department of Surgery, Yonsei University Wonju College of Medicine, Wonju, Korea
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Combination of E2F-1 promoter-regulated oncolytic adenovirus and cytokine-induced killer cells enhances the antitumor effects in an orthotopic rectal cancer model. Tumour Biol 2013; 35:1113-22. [PMID: 24037896 DOI: 10.1007/s13277-013-1149-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/26/2013] [Indexed: 12/14/2022] Open
Abstract
Due to the anatomical structure of the rectum, the treatment of rectal cancer remains challenging. Ad-E2F, an oncolytic adenovirus containing the E2F-1 promoter, can selectively replicate within and kill cancer cells derived from solid tumors. Thus, this virus provides a novel approach for the treatment of rectal cancer. Given the poor efficacy and possible adverse reactions that arise from the use of oncolytic virus alone and the results of our analysis of the efficacy of Ad-E2F in the treatment of rectal cancer, we investigated the use of oncolytic adenovirus in combination with adoptive immunotherapy using cytokine-induced killer (CIK) cells as a therapeutic treatment for rectal cancer. Our results illustrated that E2F-1 gene expression is higher in rectal cancer tissue than in normal tissue. Furthermore, the designed oncolytic adenovirus Ad-E2F is capable of selectively killing colorectal cell lines but has no significant effect on CIK cells. The results of in vitro and in vivo experiments demonstrated that combined therapy with Ad-E2F and CIK cells produce stronger antitumor effects than the administration of Ad-E2F or CIK cells alone. For low rectal cancers that are suitable for intratumoral injection, local injections of oncolytic viruses in combination with CIK cell-based adoptive immunotherapy may be suitable as a novel comprehensive therapeutic approach.
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Tenga MJ, Lazar IM. Proteomic snapshot of breast cancer cell cycle: G1/S transition point. Proteomics 2013; 13:48-60. [PMID: 23152136 DOI: 10.1002/pmic.201200188] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 09/22/2012] [Accepted: 10/25/2012] [Indexed: 01/16/2023]
Abstract
The biological processes that unfold during the G1-phase of the cell cycle are dependent on extracellular mitogenic factors that signal the cell to enter a state of quiescence, or commit to a cell-cycle round by passing the restriction point (R-point) and enter the S-phase. Unlike normal cells, cancer cells evolved the ability to evade the R-point and continue through the cell cycle even in the presence of extensive DNA damage or absence of mitogenic signals. The purpose of this study was to perform a quantitative proteomic evaluation of the biological processes that are responsible for driving MCF-7 breast cancer cells into division even when molecular checkpoints such as the G1/S R-point are in place. Nuclear and cytoplasmic fractions of the G1 and S cell-cycle phases were analyzed by LC-MS/MS to result in the confident identification of more than 2700 proteins. Statistical evaluation of the normalized data resulted in the selection of proteins that displayed twofold or more change in spectral counts in each cell state. Pathway mapping, functional annotation clustering, and protein interaction network analysis revealed that the top-scoring clusters that could play a role in overriding the G1/S transition point included DNA damage response, chromatin remodeling, transcription/translation regulation, and signaling proteins.
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Affiliation(s)
- Milagros J Tenga
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 246021, USA
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8
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Cell Proliferation (KI-67) Expression Is Associated with Poorer Prognosis in Nigerian Compared to British Breast Cancer Women. ISRN ONCOLOGY 2013; 2013:675051. [PMID: 23691362 PMCID: PMC3649293 DOI: 10.1155/2013/675051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/14/2013] [Indexed: 02/05/2023]
Abstract
Background. Black women with breast cancer (BC) in Nigeria have higher mortality rate compared with British women. This study investigated prognostic features of cell proliferation biomarker (Ki-67) in Nigerian breast cancer women. Materials and Methods. The protein expression of Ki-67 was investigated in series of 308 Nigerian women, prepared as a tissue microarray (TMA), using immunohistochemistry. Clinic-pathological parameters, biomarkers, and patient outcome of tumours expressing Ki-67 in Nigerian women were correlated with UK grade-matched series. Results. A significantly larger proportion of breast tumours from Nigerian women showed high Ki-67 expression. Those tumours were significantly correlated with negative expression of the steroid hormone receptors (ER and PgR), p21, p27, E-cadherin, BRCA-1, and Bcl-2 (all P < 0.001), but positively associated with EGFR (P = 0.003), p53, basal cytokeratins: CK56, CK14, triple negative, and basal phenotype using Nielsen's classification (all P < 0.001) compared to UK women. Multivariate analyses showed that race was also associated with BCSS independent of tumour size, lymph node status, and ER status. Conclusion. Ki-67 expression was observed to have contributed to the difference in the BCSS in Nigerian compared with British BC women. Therefore, targeting Ki-67 in the indigenous black women with BC might improve the patient outcome in the black women with BC.
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9
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Grunda JM, Steg AD, He Q, Steciuk MR, Byan-Parker S, Johnson MR, Grizzle WE. Differential expression of breast cancer-associated genes between stage- and age-matched tumor specimens from African- and Caucasian-American Women diagnosed with breast cancer. BMC Res Notes 2012; 5:248. [PMID: 22616718 PMCID: PMC3476447 DOI: 10.1186/1756-0500-5-248] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 04/25/2012] [Indexed: 11/24/2022] Open
Abstract
Background Recent studies suggest that the poorer breast cancer outcome observed in African-American women (AAW) may, in part, result from underlying molecular factors. The purpose of this study was to investigate gene expression differences between Caucasian-American women (CAW) and AAW that may contribute to this poorer prognosis. Methods The expression of 84 genes involved in breast carcinoma prognosis, response to therapy, estrogen signaling, and tumor aggressiveness was assessed in age- and stage-matched CAW and AAW paraffin-embedded breast cancer specimens. The Wilcoxon–Mann–Whitney Test was used to identify genes with a significant difference in expression between CAW and AAW. To determine if the differentially expressed genes could segregate between the CAW and AAW, we performed semi-supervised principal component analysis (SSPCA). Results Twenty genes were differentially expressed between AAW and CAW. SSPCA incorporating these 20 genes segregated AAW and CAW into two distinct groups. AAW were significantly (p < 0.05) more likely to display aberrations in G1/S cell-cycle regulatory genes, decreased expression of cell-adhesion genes, and low to no expression of ESR1, PGR, ERBB2 and estrogen pathway targets. Conclusions The gene expression differences identified between AAW and CAW may contribute to more aggressive disease, resistance to therapy, enhanced metastatic potential and poor clinical outcome. These findings support the hypothesis that breast cancer specimens collected from AAW display distinct gene expression differences compared to similar tissues obtained from CAW. Additional population-based studies are necessary to determine if these gene expression variations contribute to the highly aggressive and treatment-resistant breast cancer phenotype frequently observed in AAW.
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Affiliation(s)
- Jessica M Grunda
- Department of Medicine, Division of Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Elayat G, Selim AGA, Gorman P, Tomlinson I, Wells CA. Cyclin D-1 protein over-expression is not associated with gene amplification in benign and atypical apocrine lesions of the breast. Pathol Res Pract 2010; 207:75-8. [PMID: 21159451 DOI: 10.1016/j.prp.2010.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 05/31/2010] [Accepted: 06/09/2010] [Indexed: 11/30/2022]
Abstract
Cyclin D-1 protein over-expression and/or gene amplification have been shown to be frequent events in subsets of breast carcinomas. Cyclin D-1 is generally considered as a weak oncogene, and its over-expression has been shown to occur in occasional benign breast lesions. In a previous series, we have shown that cyclin D-1 was over-expressed in subsets of apocrine metaplasia (APM) and apocrine adenosis (AA) of the breast and that such over-expression was mostly associated with a significant increase in the proliferative capacity of these lesions. We examined the mechanisms involved in cyclin D-1 over-expression in apocrine lesions. A total of 41 cases were analysed in this study. The cases were divided into: 18 cases of APM and 23 cases of AA. All cases analysed had been previously analysed by immunohistochemistry, and all showed over-expression of the cyclin D-1 protein. Fluorescence in situ hybridisation (FISH) was performed using a dual cyclin D-1 (spectrum orange)/chromosome 11 centromere (spectrum green) DNA probe. The results showed that none of the cases studied had concomitant gene amplification. These results suggest that other post-transcriptional mechanisms might be responsible for cyclin D-1 protein over-expression in benign apocrine lesions. Further studies are needed to understand the mechanisms involved in abnormal cyclin D-1 expression in these lesions.
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Affiliation(s)
- Ghada Elayat
- Department of Histopathology, Queen Mary College, University of London, St Bartholomew's Hospital, West Smithfield, London, EC1A 7BE, UK
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Ertel A, Dean JL, Rui H, Liu C, Witkiewicz AK, Knudsen KE, Knudsen ES. RB-pathway disruption in breast cancer: differential association with disease subtypes, disease-specific prognosis and therapeutic response. Cell Cycle 2010; 9:4153-63. [PMID: 20948315 DOI: 10.4161/cc.9.20.13454] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In breast cancer, inactivation of the RB tumor suppressor gene is believed to occur via multiple mechanisms to facilitate tumorigenesis. However, the prognostic and predictive value of RB status in disease-specific clinical outcomes has remained uncertain. We investigated RB pathway deregulation in the context of both ER-positive and ER-negative disease using combined microarray datasets encompassing over 900 breast cancer patient samples. Disease-specific characteristics of RB pathway deregulation were investigated in this dataset by evaluating correlation among pathway genes as well as differential expression across patient tumor populations defined by ER status. Survival analysis among these breast cancer samples demonstrates that the RB-loss signature is associated with poor disease outcome within several independent cohorts. Within the ER-negative subpopulation, the RB-loss signature is associated with improved response to chemotherapy and longer relapse-free survival. Additionally, while individual genes in the RB target signature closely reproduce its prognostic value, they also serve to predict and monitor response to therapeutic compounds, such as the cytostatic agent PD-0332991. These results indicate that the RB-loss signature expression is associated with poor outcome in breast cancer, but predicts improved response to chemotherapy based on data in ER-negative populations. While the RB-loss signature, as a whole, demonstrates prognostic and predictive utility, a small subset of markers could be sufficient to stratify patients based on RB function and inform the selection of appropriate therapeutic regimens.
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Affiliation(s)
- Adam Ertel
- Kimmel Cancer Center, Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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Gustafsson N, Zhao C, Gustafsson JÅ, Dahlman-Wright K. RBCK1 Drives Breast Cancer Cell Proliferation by Promoting Transcription of Estrogen Receptor α and Cyclin B1. Cancer Res 2010; 70:1265-74. [DOI: 10.1158/0008-5472.can-09-2674] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Elayat G, Selim AGA, Wells CA. Alterations of the cell cycle regulators cyclin D1, cyclin A, p27, p21, p16, and pRb in apocrine metaplasia of the breast. Breast J 2009; 15:475-82. [PMID: 19624419 DOI: 10.1111/j.1524-4741.2009.00762.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
G1/S transition defects have been a proposed requirement for tumor development. Apocrine metaplasia (APM) in the breast has been held as a sign of benignity. Yet, a number of studies have reported the presence of molecular abnormalities in some forms of APM suggesting a possible oncogenic potential for some of these lesions. We currently investigate the role of some of the cell cycle proteins, previously reported to be de-regulated in breast cancer, in an attempt to assess their significance in APM. Using immunohistochemistry, the expression of cyclin D1, cyclin A, p27, p21, p16, pRb and Ki-67 was examined in 93 cases of APM. The cases were divided into nonpapillary (NAPM) (30 cases) and papillary metaplasia (PAPM) (63 cases). PAPM was further subdivided into simple papillary (SPAPM) (29 cases), complex papillary (28 cases) and highly complex papillary (six cases). For statistical analysis, the last two groups were merged together (CPAPM). The results showed that increased histological complexity was associated with significant increase of proliferative capacity and alterations of the cell cycle control. The median Ki-67 index was 1.5% in SPAPM and 4.8% in the CPAPM. Also, alterations of the cell cycle regulators were significantly higher in the CPAPM than in the SPAPM. NAPM was generally similar to normal breast epithelium. Apocrine cells were negative for p16 while pRb was expressed in all cases. These findings suggest that in complex forms of APM, there is a considerable degree of cellular unrest. This may contribute to increased susceptibility to carcinogenesis.
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Affiliation(s)
- Ghada Elayat
- Department of Histopathology, St Bartholomew's Hospital, West Smithfield, London, United Kingdom
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Wang L, Shao ZM. Cyclin E Expression and Prognosis in Breast Cancer Patients: A Meta-Analysis of Published Studies. Cancer Invest 2009; 24:581-7. [PMID: 16982462 DOI: 10.1080/07357900600894799] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In vitro studies showed that cyclin E can accelerate the cell cycle by shorten the G1/S phase transition. Therefore, varieties of studies have investigated the relationship between cyclin E and survival in breast cancer patients. However, the results differed widely between studies. We reviewed the published studies and performed a meta-analysis, which including 12 independent studies and 2,534 patients. The combined HR estimate for relapse-free survival (RFS) was 2.32 (95% CI, 1.25-4.30) and 1.72 (95% CI, 0.95-3.10) in univariate and multivariate analysis, respectively. In addition, the combined HR estimate for overall survival (OS) and breast cancer specific survival (BCSS) was 2.98 (95% CI, 1.85-4.78) and 2.86 (95% CI, 1.85-4.41) in univariate and multivariate analysis, respectively. In conclusion, the high level of cyclin E appears to be an independent prognostic factor to OS/BCSS of breast cancer patients but not to RFS.
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Affiliation(s)
- Lei Wang
- Department of Breast Surgery, Department of Oncology, Cancer Hospital/Cancer Institute, Fudan University, Shanghai, China
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Abstract
The retinoblastoma tumour suppressor (RB) is a crucial regulator of cell-cycle progression that is invoked in response to a myriad of anti-mitogenic signals. It has been hypothesized that perturbations of the RB pathway confer a synonymous proliferative advantage to tumour cells; however, recent findings demonstrate context-specific outcomes associated with such lesions. Particularly, loss of RB function is associated with differential response to wide-ranging therapeutic agents. Thus, the status of this tumour suppressor may be particularly informative in directing treatment regimens.
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Affiliation(s)
- Erik S Knudsen
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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Borgquist S, Anagnostaki L, Jirström K, Landberg G, Manjer J. Breast tumours following combined hormone replacement therapy express favourable prognostic factors. Int J Cancer 2007; 120:2202-7. [PMID: 17278089 DOI: 10.1002/ijc.22542] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The aim of the present study was to evaluate the association between different types of hormone replacement therapy (HRT) and risk of specific breast cancer subgroups. A population-based prospective cohort study including 12,583 peri- or postmenopausal women were followed using record-linkage with national cancer registries. During an average follow-up of 4.5 years, 332 cases of invasive breast cancer were diagnosed. Tumour samples were available from 283 cases. These tumours were re-evaluated according to histological type, grade, and mitotic index. Evaluation of tumours included estrogen and progesterone receptor status (ERalpha, ERbeta and PgR), as well as expression of Ki67, HER2, cyclin D1 and p27. The incidence of breast cancer in current users of combined HRT (CHRT) was significantly higher than in non-users. The difference corresponded to an adjusted relative risk (95% confidence interval) of 3.01 (2.35-3.84) as obtained using a Cox's proportional hazards analysis. CHRT was associated with lobular tumours (3.48:1.99-6.10), grade 1 tumours (4.46:2.79-7.13) and tumours with a low mitotic index (4.35:2.99-6.34). CHRT was not related to any specific subgroup in terms of ERalpha-, ERbeta- or PgR-expression. CHRT was associated with low proliferating tumours, defined by the Ki67 index (3.58:2.60-4.93), HER2 amplified tumours (4.40:1.93-10.06), low expression of the oncogene cyclin D1 (3.14:2.32-4.23) and high expression of the tumour suppressor gene p27 (3.47:2.40-5.01). Use of estrogen-alone HRT (ERT) was not associated with any statistically significant risk of breast cancer. We conclude that the use of CHRT is associated with an increased incidence of breast tumours with comparatively favourable prognostic factors.
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Affiliation(s)
- Signe Borgquist
- Department of Laboratory Medicine, Division of Pathology, Malmö University Hospital, Lund University, SE-20502 Malmö, Sweden.
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Borgquist S, Wirfält E, Jirström K, Anagnostaki L, Gullberg B, Berglund G, Manjer J, Landberg G. Diet and body constitution in relation to subgroups of breast cancer defined by tumour grade, proliferation and key cell cycle regulators. Breast Cancer Res 2007; 9:R11. [PMID: 17254341 PMCID: PMC1851395 DOI: 10.1186/bcr1644] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 01/07/2007] [Accepted: 01/25/2007] [Indexed: 12/23/2022] Open
Abstract
Background The general lack of clear associations between diet and breast cancer in epidemiological studies may partly be explained by the fact that breast cancer is a heterogeneous disease that may have disparate genetic associations and different aetiological bases. Method A total of 346 incident breast cancers in a prospective cohort of 17,035 women enrolled in the Malmö Diet and Cancer study (Sweden) were subcategorized according to conventional pathology parameters, proliferation and expression of key cell cycle regulators. Subcategories were compared with prediagnostic diet and body measurements using analysis of variance. Results A large hip circumference and high body mass index were associated with high grade tumours (P = 0.03 and 0.009, respectively), whereas low energy and unadjusted fat intakes were associated with high proliferation (P = 0.03 and 0.004, respectively). Low intakes of saturated, monounsaturated and polyunsaturated fatty acids were also associated with high proliferation (P = 0.02, 0.004 and 0.003, respectively). Low energy and unadjusted fat intakes were associated with cyclin D1 overexpression (P = 0.02 and 0.007, respectively), whereas cyclin E overexpression was positively correlated with fat intake. Oestrogen receptor status and expression of the tumour suppressor gene p27 were not associated with either diet or body constitution. Conclusion Low energy and low total fat (polyunsaturated fatty acids in particular) intakes, and high body mass index were associated with relatively more malignant breast tumours. Dietary behaviours and body constitution may be associated with specific types of breast cancer defined by conventional pathology parameters and cyclin D1 and cyclin E expression. Further studies including healthy control individuals are needed to confirm our results.
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Affiliation(s)
- Signe Borgquist
- Division of Pathology, Department of Laboratory Medicine, Malmö University Hospital, S-205 02 Malmö, Sweden
- Division of Oncology, Department of Clinical Sciences, Lund University Hospital, S-221 85 Lund, Sweden
| | - Elisabet Wirfält
- Department of Clinical Sciences, Malmö University Hospital, S-205 02 Malmö, Sweden
| | - Karin Jirström
- Division of Pathology, Department of Laboratory Medicine, Malmö University Hospital, S-205 02 Malmö, Sweden
| | - Lola Anagnostaki
- Division of Pathology, Department of Laboratory Medicine, Malmö University Hospital, S-205 02 Malmö, Sweden
| | - Bo Gullberg
- Department of Clinical Sciences, Malmö University Hospital, S-205 02 Malmö, Sweden
| | - Göran Berglund
- Department of Clinical Sciences, Malmö University Hospital, S-205 02 Malmö, Sweden
| | - Jonas Manjer
- Department of Surgery, Malmö University Hospital, S-205 02 Malmö. Sweden
| | - Göran Landberg
- Division of Pathology, Department of Laboratory Medicine, Malmö University Hospital, S-205 02 Malmö, Sweden
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19
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Erlandsson F, Martinsson-Ahlzén HS, Wallin KL, Hellström AC, Andersson S, Zetterberg A. Parallel cyclin E and cyclin A expression in neoplastic lesions of the uterine cervix. Br J Cancer 2006; 94:1045-50. [PMID: 16538218 PMCID: PMC2361235 DOI: 10.1038/sj.bjc.6603038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cyclin E levels are high during late G1 and early S-phase in normal cells. The cyclin E expression over the cell cycle in tumours is not fully known. The impact on patient outcome by high cyclin E levels during other parts of the cell cycle than late G1- and early S-phase is unknown. We set out to study the expression of cyclin E over the cell cycle in cervical carcinomas. Using immunofluorescence staining of cyclin A, digital microscopy, and digital image analysis, we determined which cells in a tissue section that were in S- or G2-phase. M-phase cells were detected by morphology. By simultaneously staining for cyclin E, we investigated the variation in cyclin E levels over the cell cycle in cervical carcinoma lesions. In a case–control study, in which each deceased patient was matched with a patient still alive and well after >5 years of follow-up, we found that the deceased patients had a considerably higher fraction of cyclin A-positive cells staining for cyclin E than the survivors (n=36). We conclude that parallel cyclin E and cyclin A expression is an indicator for poor outcome in cervical carcinomas. In addition, we investigated the expression pattern of cyclin E and cyclin A in consecutive biopsy samples from cervical carcinomas at different stages, as well as in human papillomavirus positive or negative adenocarcinomas in order to further study the cyclin E and cyclin A expression pattern in neoplastic lesions of the uterine cervix.
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Affiliation(s)
- F Erlandsson
- Cancer Center Karolinska, CCK R8:04, Karolinska University Hospital Solna, Karolinska Institutet, Stockholm 17176, Sweden.
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20
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Roy PG, Thompson AM. Cyclin D1 and breast cancer. Breast 2006; 15:718-27. [PMID: 16675218 DOI: 10.1016/j.breast.2006.02.005] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 02/23/2006] [Accepted: 02/24/2006] [Indexed: 11/20/2022] Open
Abstract
Cyclin D1 is one of the frequently overexpressed proteins and one of the commonly amplified genes in breast cancer. This article reviews the roles of cyclin D1 in cell-cycle regulation (normal and abnormal), mammary gland development and carcinogenesis and the relationship to oestrogen in breast tissues. It concludes by presenting the clinical, prognostic and therapeutic implications of our current knowledge of cyclin D1 in breast cancer.
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Affiliation(s)
- Pankaj G Roy
- Department of Surgery & Molecular Oncology, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
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21
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Grupka NL, Bloom C, Singh M. Expression of retinoblastoma protein in breast cancer metastases to sentinel nodes: evaluation of its role as a marker for the presence of metastases in non-sentinel axillary nodes, and comparison to p16INK4a. Appl Immunohistochem Mol Morphol 2006; 14:63-70. [PMID: 16540733 DOI: 10.1097/01.pai.0000161486.72621.4a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The aim of this study was to evaluate the role of retinoblastoma protein (pRb), alone and in combination with p16, as a predictive marker for metastases in non-sentinel nodes in cases where the sentinel node showed metastatic breast carcinoma. Paraffin blocks of lymph nodes from 48 patients with metastatic breast carcinoma were immunostained with a monoclonal antibody to retinoblastoma protein (PharMingen). Results were compared with known prognostic parameters of the primary tumor, estrogen and progesterone receptor status, proliferation index, and p16 (DAKO) expression. Lymph nodes from 38 of the 48 (79%) cases were pRb positive. There was no correlation of pRb staining alone with the primary tumor parameters studied or the proliferative index of the metastatic tumor. In 16 patients with both a sentinel node biopsy and an axillary lymph node dissection, 8 (50%) had metastatic breast carcinoma. The sentinel nodes of three of these eight patients (38%) were pRb negative (positive predictive value of 60% vs. 73% for p16). The remaining eight patients (50%) had no metastases in non-sentinel nodes, even though their sentinel nodes had metastatic breast carcinoma; six of these eight patients (75%) were pRb positive (negative predictive value of 55% vs. 83% for p16). pRb and p16 staining results combined showed that pRb-negative/p16-positive cases were associated with non-sentinel node metastases (positive predictive value of 100%) as well as poor prognostic parameters. Patients with the opposite staining profile (pRb positive and p16 negative) were mostly without non-sentinel node metastases (negative predictive value of 75%). Cases negative for both pRb and p16 were consistently associated with a better prognostic phenotype and absence of additional axillary node metastases. In conclusion, the presence or absence of pRb in sentinel nodes is of little predictive value for non-sentinel node metastases unless taken in conjunction with the presence of p16 staining. Instead, it appears to enhance the positive predictive value of p16 in determining the presence of non-sentinel node metastases. Due to the limited subgroup sample size in this study, clinical guidelines cannot be suggested as yet, but further research focused on the pRb-negative/p16-positivie and pRb-negative/p16-negative phenotypes may yield beneficial results.
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Affiliation(s)
- Nichon L Grupka
- Department of Pathology, University of Colorado Health Sciences Center, Denver, Colorado 80045, USA
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22
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Shah A, Swain WA, Richardson D, Edwards J, Stewart DJ, Richardson CM, Swinson DEB, Patel D, Jones JL, O'Byrne KJ. Phospho-akt expression is associated with a favorable outcome in non-small cell lung cancer. Clin Cancer Res 2005; 11:2930-6. [PMID: 15837744 DOI: 10.1158/1078-0432.ccr-04-1385] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Akt, a Serine/Threonine protein kinase, mediates growth factor-associated cell survival. Constitutive activation of Akt (phosphorylated Akt, P-Akt) has been observed in several human cancers, including lung cancer and may be associated with poor prognosis and chemotherapy and radiotherapy resistance. The clinical relevance of P-Akt in non-small cell lung cancer (NSCLC) is not well described. In the present study, we examined 82 surgically resected snap-frozen and paraffin-embedded stage I to IIIA NSCLC samples for P-Akt and Akt by Western blotting and for P-Akt by immunohistochemistry. P-Akt protein levels above the median, measured using reproducible semiquantitative band densitometry, correlated with a favorable outcome (P = 0.007). Multivariate analysis identified P-Akt as a significant independent favorable prognostic factor (P = 0.004). Although associated with a favorable prognosis, high P-Akt levels correlated with high tumor grade (P = 0.02). Adenocarcinomas were associated with low P-Akt levels (P = 0.039). Akt was not associated with either outcome or clinicopathologic variables. Cytoplasmic (CP-Akt) and nuclear (NP-Akt) P-Akt tumor cell staining was detected in 96% and 42% of cases, respectively. Both CP-Akt and NP-Akt correlated with well-differentiated tumors (P = 0.008 and 0.017, respectively). NP-Akt also correlated with nodal metastases (P = 0.022) and squamous histology (P = 0.037).These results suggest P-Akt expression is a favorable prognostic factor in NSCLC. Immunolocalization of P-Akt, however, may be relevant as NP-Akt was associated with nodal metastases, a known poor prognostic feature in this disease. P-Akt may be a potential novel therapeutic target for the management of NSCLC.
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Affiliation(s)
- Amit Shah
- University Department of Oncology, University of Leicester, Leicester, United Kingdom
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23
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Sandhu C, Connor M, Kislinger T, Slingerland J, Emili A. Global Protein Shotgun Expression Profiling of Proliferating MCF-7 Breast Cancer Cells. J Proteome Res 2005; 4:674-89. [PMID: 15952714 DOI: 10.1021/pr0498842] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein expression becomes altered in breast epithelium during malignant transformation. Knowledge of these perturbations should provide insight into the molecular basis of breast cancer, as well as reveal possible new therapeutic targets. To this end, we have performed an extensive comparative proteomic survey of global protein expression patterns in proliferating MCF-7 breast cancer cells and normal human mammary epithelial cells using gel-free shotgun tandem mass spectrometry. Pathophysiological alterations associated with the malignant breast cancer phenotype were detected, including differences in the apparent levels of key regulators of the cell cycle, signal transduction, apoptosis, transcriptional regulation, and cell metabolism.
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Affiliation(s)
- Charanjit Sandhu
- Program in Proteomics and Bioinformatics, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
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24
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Wingate H, Zhang N, McGarhen MJ, Bedrosian I, Harper JW, Keyomarsi K. The Tumor-specific Hyperactive Forms of Cyclin E Are Resistant to Inhibition by p21 and p27. J Biol Chem 2005; 280:15148-57. [PMID: 15708847 DOI: 10.1074/jbc.m409789200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The low molecular weight (LMW) isoforms of cyclin E are unique to cancer cells. In breast cancer, such alteration of cyclin E is a very strong predictor of poor patient outcome. Here we show that alteration in binding properties of these LMW isoforms to CDK2 and the CDK inhibitors (CKIs), p21 and p27, results in their functional hyperactivity. The LMW forms of cyclin E are severalfold more effective at binding to CDK2. Additionally, compared with the full-length cyclin E-CDK2 complexes, the LMW cyclin E-CDK2 complexes are significantly more resistant to inhibition by p21 and p27, despite equal binding of the CKIs to the LMW complexes. When both the full-length and the LMW cyclin E are co-expressed, p27 preferentially binds to the LMW forms yet is unable to inhibit the CDK2 activity. Thus, the LMW forms of cyclin E may contribute to tumorigenesis through their resistance to the inhibitory activities of p21 and p27 while sequestering these CKIs from the full-length cyclin E.
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Affiliation(s)
- Hannah Wingate
- Department of Experimental Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4095, USA
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25
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Abstract
The proto-oncogene cyclin D1 has been implicated in the genesis of a large proportion of human tumors from diverse histological origins. It has long been assumed that the action of cyclin D1, as an activator of cdk4 and cdk6 and leading to progression through the G1 phase of the cell cycle, underlies its pathological activity. But, more recently, analyses of the patterns of gene expression in human cancer have revealed a previously unappreciated mechanism of action for cyclin D1, suggesting that both cdk-dependent and cdk-independent activities might contribute to tumorigenesis. The development of therapeutics designed to target the aberrant activity of cyclin D1 in human cancers will rely upon an intimate molecular understanding of these distinct mechanisms of actions and their relative importance. Here, we describe the known functions of the cyclin D1 oncogene and delineate the evidence that cdk-independent actions are important for cyclin D1-mediated oncogenesis.
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Affiliation(s)
- Mark E Ewen
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA.
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26
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Derenzini M, Ceccarelli C, Santini D, Taffurelli M, Treré D. The prognostic value of the AgNOR parameter in human breast cancer depends on the pRb and p53 status. J Clin Pathol 2004; 57:755-61. [PMID: 15220371 PMCID: PMC1770366 DOI: 10.1136/jcp.2003.015917] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The amount of argyrophilic nucleolar organiser regions (AgNORs) represents a cell kinetics parameter used in tumour pathology for prognostic purposes. AgNOR expression is directly related to the rate of ribosome biogenesis, which has been recently shown to be controlled also by the tumour suppressor proteins pRb and p53. AIMS To ascertain the relative prognostic value of AgNORs and of pRb and p53 expression in breast carcinoma. METHODS This study was carried out on 335 human primary breast carcinomas with a median follow up time of 108 months. AgNORs were measured by morphometric analysis on sections that had been selectively silver stained; expression of p53 and phosphorylated and non-phosphorylated pRb forms was assessed by immunohistochemistry. RESULTS Patients were divided into groups with low (249) and high (86) AgNOR values; with normal (267) and mutated p53 (68); and with normal (256) and hyperphosphorylated or deleted pRb (79). Univariate analysis of disease free survival showed that AgNORs and the status of pRb and p53 were significantly related to the patients' clinical outcome. However, among the four groups characterised by different pRb and p53 status, the AgNOR parameter was not capable of distinguishing subgroups of patients with different clinical outcomes. CONCLUSIONS These findings indicate that the prognostic value of the AgNOR parameter depends on the status of the tumour suppressor proteins pRb and p53, and it cannot be ascribed to the relation between AgNORs and the cell proliferation rate.
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Affiliation(s)
- M Derenzini
- Department of Experimental Pathology, Unit of Clinical Pathology, University of Bologna, Bologna 40126, Italy.
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27
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Ekholm-Reed S, Méndez J, Tedesco D, Zetterberg A, Stillman B, Reed SI. Deregulation of cyclin E in human cells interferes with prereplication complex assembly. ACTA ACUST UNITED AC 2004; 165:789-800. [PMID: 15197178 PMCID: PMC2172392 DOI: 10.1083/jcb.200404092] [Citation(s) in RCA: 229] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Deregulation of cyclin E expression has been associated with a broad spectrum of human malignancies. Analysis of DNA replication in cells constitutively expressing cyclin E at levels similar to those observed in a subset of tumor-derived cell lines indicates that initiation of replication and possibly fork movement are severely impaired. Such cells show a specific defect in loading of initiator proteins Mcm4, Mcm7, and to a lesser degree, Mcm2 onto chromatin during telophase and early G1 when Mcm2-7 are normally recruited to license origins of replication. Because minichromosome maintenance complex proteins are thought to function as a heterohexamer, loading of Mcm2-, Mcm4-, and Mcm7-depleted complexes is likely to underlie the S phase defects observed in cyclin E-deregulated cells, consistent with a role for minichromosome maintenance complex proteins in initiation of replication and fork movement. Cyclin E-mediated impairment of DNA replication provides a potential mechanism for chromosome instability observed as a consequence of cyclin E deregulation.
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Affiliation(s)
- Susanna Ekholm-Reed
- Dept. of Molecular Biology, MB-7, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA.
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28
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Jirström K, Ringberg A, Fernö M, Anagnostaki L, Landberg G. Tissue microarray analyses of G1/S-regulatory proteins in ductal carcinoma in situ of the breast indicate that low cyclin D1 is associated with local recurrence. Br J Cancer 2004; 89:1920-6. [PMID: 14612904 PMCID: PMC2394433 DOI: 10.1038/sj.bjc.6601398] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ductal carcinoma in situ (DCIS) of the breast constitutes about 10% of all diagnosed breast cancers and, despite surgical removal, it may recur, either as DCIS or invasive breast cancer. Nuclear grade and growth pattern according to Andersen et al as well as surgical margins are factors that have been used to predict local recurrence, but ideally a set of tumour-specific factors should be identified and used as prognostic markers. Many cell cycle regulatory gene products have been shown to be involved in the formation of tumours and are either oncogenes or suppressor genes and involved in key processes in the transformation. We therefore characterised the cell cycle regulators cyclin E, cyclin D1, p27 and p16 in a material of DCIS cases arranged in a tissue microarray. With a manual tissue arrayer, 52% of the initial 177 DCIS samples were successfully targeted allowing immunohistochemical analyses of all four proteins in 92 cases of DCIS. As also observed in invasive breast cancer, there was a trend indicating that DCIS cases with high cyclin D1 were cyclin E low and oestrogen receptor-positive, whereas cyclin E high DCIS cases were cyclin D1 low and oestrogen receptor-negative. For the 64 patients that did not receive postoperative radiotherapy, there were 16 local recurrences (eight DCIS and eight invasive breast cancer) during a mean follow-up time of 63 months. Cyclin E, p27 or p16 were not associated with local recurrence, but interestingly cyclin D1 was significantly and inversely associated with local recurrence, both using univariate and multivariate analyses. In summary, using a tissue array approach we have shown that cyclin D1, besides growth pattern, is a prognostic marker for local recurrence in DCIS.
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Affiliation(s)
- K Jirström
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, S-205 02, Malmö, Sweden
| | - A Ringberg
- Department of Plastic and Reconstructive Surgery, Lund University, Malmö University Hospital, Sweden
| | - M Fernö
- Department of Oncology, University Hospital Lund, Sweden
| | - L Anagnostaki
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, S-205 02, Malmö, Sweden
| | - G Landberg
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, S-205 02, Malmö, Sweden
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, S-205 02, Malmö, Sweden. E-mail:
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29
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Porter PL, Lund MJ, Lin MG, Yuan X, Liff JM, Flagg EW, Coates RJ, Eley JW. Racial differences in the expression of cell cycle-regulatory proteins in breast carcinoma. Cancer 2004; 100:2533-42. [PMID: 15197793 DOI: 10.1002/cncr.20279] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND African-American (AA) women are more likely to be diagnosed with an advanced stage of breast carcinoma than are white women. After adjustment for disease stage, many studies indicate that tumors in AA women are more likely than tumors in white women are to exhibit a high level of cell proliferation and features of poor prognosis. The purpose of the current study was to compare tumor characteristics and cell cycle alterations in AA women and white women that might affect the aggressiveness of breast carcinoma. METHODS The study included 124 AA and 397 white women, ages 20-54 years. These women were enrolled in a case-control study in Atlanta, Georgia, between 1990 and 1992. Breast tumor specimens obtained from these women were centrally reviewed for histologic characteristics and evaluated for expression of estrogen and progesterone receptors (ER/PR), c-ErbB-2, Ki-67, p53, cyclin E, cyclin D1, p27, p16, pRb, and p21 by immunohistochemistry. Logistic regression models were used to assess the age- and stage-adjusted associations of various tumor characteristics with race. RESULTS The odds of a breast carcinoma diagnosis at a younger age and at a later stage were higher for AA women than for white women. After adjustment for disease stage and age at diagnosis, AA women also were found to have increased odds of having a higher-grade tumor, a higher mitotic index, marked tumor necrosis, ductal histology, loss of ER and PR, overexpression of cyclin E, p16, and p53 and low expression of cyclin D1 at diagnosis. CONCLUSIONS The observed differences between tumor specimens obtained from AA women and tumor specimens obtained from white women, independent of stage and age at diagnosis, indicated that race may be a determinant, or a surrogate for other determinants, of aggressive breast carcinoma and specific cell cycle defects.
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Affiliation(s)
- Peggy L Porter
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
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30
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Abstract
Breast cancer is a genetic disease. Like other human cancers, it is thought to occur as the result of progressive accumulation of genetic aberrations. These aberrations result in a deviation of the gene expression profiles from that of the normal progenitor cell. In up to 99% of cases, breast cancer is due to solely somatic genetic aberrations without germ-line ones. Considerable progress have already been made in understanding the genetic mechanisms underlying the development and progression of breast cancer. Several extensively studied genes are now well known to be involved. Unfortunately, our ability to make clinically useful interventions on the basis of these data is limited. Because of the involvement of multiple genes and complex pathways in a single cancer cell, the molecular dysfunctioning underlying breast cancer remains to be completely clarified. In a next future, studying the global gene expression of different types of tumors will allow the development of expression profiles unique for a breast cancer, its stage and prognostic category, leading to diagnostic assays and the identification of new therapeutic targets.
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Affiliation(s)
- F Lerebours
- E0017 INSERM/Oncogénétique, Centre René Huguenin, 35 rue Dailly, F-92211, St-Cloud, France.
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31
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Landberg G. Multiparameter analyses of cell cycle regulatory proteins in human breast cancer: a key to definition of separate pathways in tumorigenesis. Adv Cancer Res 2002; 84:35-56. [PMID: 11883531 DOI: 10.1016/s0065-230x(02)84002-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Breast cancer is one of the most common cancer forms affecting many women. The disease nevertheless has widely varying behavior and therefore patient outcome, and an important undertaking is to define and understand the molecular mechanisms behind these actions. Defects in the G1/S transition in the cell cycle affect both tumor proliferation and the fidelity of check points responsible for chromosomal integrity and DNA damage response and has lately been shown to represent one of a rather limited set of key aberrations in the transformation process. Many cell cycle regulatory proteins are either oncogenes or suppressor genes or are closely associated to the transformation process. The types of aberrations in the G1/S transition seem to be different in various cancers but are nevertheless often linked to clinical behaviors. In this review the role of multiparameter analyses of cell cycle regulatory proteins in breast cancer will be outlined with special attention to pattern analyses as well as the definition of two contrasting pathways in tumorigenesis defined by either cyclin D1 or cyclin F overexpression.
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Affiliation(s)
- Göran Landberg
- Department of Laboratory Medicine, Lund University, Malmö University Hospital, Sweden
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32
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Strube RW, Chen SY. Characterization of anti-cyclin E single-chain Fv antibodies and intrabodies in breast cancer cells: enhanced intracellular stability of novel sFv-F(c) intrabodies. J Immunol Methods 2002; 263:149-67. [PMID: 12009211 DOI: 10.1016/s0022-1759(02)00035-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Cyclin E is a critical cell cycle protein in the regulated progression of normal cells to replicate their DNA. Ectopic overexpression of cyclin E results in accelerated G(1) progression, chromosome instability, and a reduced requirement for growth factors. Dysregulated cyclin E expression is found in nearly all breast cancers examined. Toward the goal of developing a system to block cyclin E function in normal and breast cancer cells, we have developed anti-cyclin E single-chain antibodies (sFvs) for use as intrabodies. We have cloned the variable region genes from two hybridoma cell lines that produce anti-human cyclin E antibodies, linked them into sFvs, and showed their ability to bind cyclin E when expressed as sFv-F(c) fusion proteins. Engineering of the sFvs as sFv-F(c) intrabodies resulted in a dramatic increase in the sFv half-life as analyzed by pulse-chase and immunofluorescence, and these fusion intrabodies can be expressed in the cytosol or retargeted to the nucleus of breast cancer cell lines. Stable expression of a nuclear-targeted anti-cyclin E intrabody appears to inhibit the growth of the breast cancer cell line SKBR3. This work sets the stage for the development of intrabody-based inducible or tissue-specific cyclin E knockouts and for identifying cyclin E and its vital cell cycle functions as a potential gene therapy target in breast and other cancers.
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Affiliation(s)
- Randall W Strube
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC 27109, USA
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33
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Pérez-Tenorio G, Stål O. Activation of AKT/PKB in breast cancer predicts a worse outcome among endocrine treated patients. Br J Cancer 2002; 86:540-5. [PMID: 11870534 PMCID: PMC2375266 DOI: 10.1038/sj.bjc.6600126] [Citation(s) in RCA: 307] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2001] [Revised: 12/03/2001] [Accepted: 12/05/2001] [Indexed: 12/21/2022] Open
Abstract
Akt/PKB is a serine/threonine protein kinase that regulates cell cycle progression, apoptosis and growth factor mediated cell survival in association with tyrosine kinase receptors. The protein is a downstream effector of erbB-2 with implications in breast cancer progression and drug resistance in vitro. We aimed to examine the role of Akt-1 in breast cancer patients, by determining whether the expression (Akt-1) and/or activation (pAkt) were related to prognostic markers and survival. The expression of erbB-2, heregulin beta 1 and Bcl-2 was also assessed by flow cytometry or immunohistochemistry. This study comprised 93 patients, aged <50 who were treated with tamoxifen and/or goserelin. We found that pAkt was associated with lower S-phase fraction (P=0.001) and the presence of heregulin beta 1-expressing stromal cells (P=0.017). Neither Akt-1 nor pAkt was related with other factors. Tumour cells-derived heregulin beta 1 was found mainly in oestrogen receptor negative (P=0.026) and node negative (P=0.005) cases. Survival analysis revealed that pAkt positive patients were more prone to relapse with distant metastasis, independently of S-phase fraction and nodal status (multivariate analysis; P=0.004). The results suggest that activation of Akt may have prognostic relevance in breast cancer.
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Affiliation(s)
- G Pérez-Tenorio
- Department of Biomedicine and Surgery, Division of Oncology, Clinical Research Center, Faculty of Health Sciences, Linköping University, SE-581 85 Linköping, Sweden.
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Michalides R, van Tinteren H, Balkenende A, Vermorken JB, Benraadt J, Huldij J, van Diest P. Cyclin A is a prognostic indicator in early stage breast cancer with and without tamoxifen treatment. Br J Cancer 2002; 86:402-8. [PMID: 11875707 PMCID: PMC2375223 DOI: 10.1038/sj.bjc.6600072] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2001] [Revised: 11/05/2001] [Accepted: 11/14/2001] [Indexed: 11/30/2022] Open
Abstract
Overexpression of G1-S regulators cyclin D1 or cyclin A is frequently observed in breast cancer and is also to result in ligand-independent activation of oestrogen receptor in vitro. This might therefore, provide a mechanism for failure of tamoxifen treatment. We examined by immunohistochemical staining the effect of deregulation of these, and other cell cycle regulators on tamoxifen treatment in a group of 394 patients with early stage breast cancer. In univariate analysis, expression of cyclin A, Neu, Ki-67 index, and lack of OR expression were significantly associated with worse prognosis. When adjusted by the clinical model (for lymph node status, age, performance status, T-classification, grade, prior surgery, oestrogen receptor status and tamoxifen use), only overexpression of cyclin A and Neu were significantly associated with worse prognosis with hazard ratios of, respectively, 1.709 (P=0.0195) and 1.884 (P=0.0151). Overexpression of cyclin A was found in 86 out of the 201 OR-positive cases treated with tamoxifen, and was the only independent marker associated with worse prognosis (hazard ratio 2.024, P=0.0462). In conclusion, cyclin A is an independent predictor of recurrence of early stage breast cancer and is as such a marker for response in patients treated with tamoxifen.
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Affiliation(s)
- R Michalides
- Division of Tumour Biology, the Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
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35
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Abstract
Clinical and experimental data have established that the leading cause of sporadic female breast cancer is exposure to estrogens, predominantly 17beta-estradiol. Recent advances in the understanding of cell-cycle control mechanisms have been applied to outline the molecular mechanisms through which estrogens regulate the cell cycle in cultured breast cancer cells, in particular, in MCF-7 cells. Here, we discuss how estrogens exert control over several key G1 phase cell-cycle regulators, namely cyclin D1, Myc, Cdk2, Cdk4, Cdk inhibitors and Cdc25A. Although the molecular mechanisms underlying estrogenic regulation of G1 phase regulators are far from clear, current evidence indicates that estrogens might regulate several key molecules required for S phase entry, this regulation being independent of cell-cycle transit per se.
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Affiliation(s)
- J S Foster
- Dept of OB/GYN, Graduate School of Medicine, University of Tennessee, Knoxville, TN 37920, USA
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36
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Maitra A, Roberts H, Weinberg AG, Geradts J. Aberrant expression of tumor suppressor proteins in the Ewing family of tumors. Arch Pathol Lab Med 2001; 125:1207-12. [PMID: 11520274 DOI: 10.5858/2001-125-1207-aeotsp] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Deregulation of tumor suppressor gene function and abrogation of cell cycle control are common features of malignant neoplasms, but corresponding data on Ewing sarcomas and primitive neuroectodermal tumors are relatively scarce. We studied the expression of 4 tumor suppressor proteins in the Ewing family of tumors (EFTs). DESIGN We examined a series of 20 pediatric EFTs for abnormal expression of p16(INK4a), p14(ARF), p21(WAF1), and pRB by immunohistochemical analysis of pretreatment, nondecalcified archival specimens. Clinical follow up was available in all cases (median, 21 months; range, 5-103 months). Five patients presented with metastatic disease, 8 had no evidence of disease at last follow up, and 12 had an adverse outcome (death or progressive tumor posttherapy). RESULTS Twelve cases (60%) demonstrated abnormal expression of at least one tumor suppressor protein. There were 11 cases (55%) with loss of p21(WAF1) expression, 4 (20%) with down-regulation of p16(INK4a), 2 (10%) with absence of pRB, and one case (5%) with loss of p14(ARF) expression. Loss of p16(INK4a) expression correlated with metastatic disease at presentation (P =.026), and showed a trend toward shortened survival (P =.20). The p21(WAF1), p14(ARF), and pRB status was not significantly correlated with either metastatic disease at presentation or outcome. CONCLUSION Abrogation of the G1 checkpoint was common in this series of EFTs, and down-regulation of p21(WAF1) and p16(INK4a) were the most frequent findings. Loss of p16(INK4a) expression may identify a subset of cases with a more aggressive phenotype.
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Affiliation(s)
- A Maitra
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, USA.
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37
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Bozcuk H, Uslu G, Peştereli E, Samur M, Ozdoğan M, Karaveli S, Sargin F, Savaş B. Predictors of distant metastasis at presentation in breast cancer: a study also evaluating associations among common biological indicators. Breast Cancer Res Treat 2001; 68:239-48. [PMID: 11727960 DOI: 10.1023/a:1012269804578] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND To investigate the correlation among some of the commonly used clinical, pathological factors and newer biological indicators, and to identify the independent predictors of distant metastasis at presentation in patients with breast cancer. METHODS The pathological specimens from 73 patients with breast cancer were retrospectively evaluated by immunohistochemistry. Data on 13 biological indicators; ER, PR, P53, c-erbB-2, PCNA, CEA, Ki-67, Vimentin, Ulex, Nm23, Cathepsin D, Factor VIII, PS2 together with clinical and pathological factors were collected. RESULTS A number of highly significant correlations were found among the biological indicators studied. By logistic regression analysis, the predictors of distant metastasis at presentation in univariate tests were tumor diameter, number of lymph nodes involved, P53, c-erbB-2 and grade. In multivariate analysis, tumor diameter (P = 0.042, HR: 1.88(1.02-3.44)), c-erbB-2 expression (P=0.035, HR: 18.20 (1.23-268.66)) and grade (P=0.010, HR: 8.05(1.66-39.00)) retained their significance. CONCLUSION Our findings show that inactivation of suppressor genes, expression of oncogenes, loss of differentiation, augmentation of proliferative activity, metastatic potential, angiogenesis and hormone receptor status are all interrelated facets of breast cancer pathogenesis. Patients with tumors overexpressing c-erbB-2 or with bigger or higher-grade tumors probably need to be more carefully evaluated for the presence of distant metastasis, thus be better staged, at presentation. This may be a new reason to test c-erbB-2 routinely in all patients with breast cancer in addition to its well-known prognostic and predictive uses.
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Affiliation(s)
- H Bozcuk
- Department of Internal medicine, Akdeniz University Medical Faculty, Antalya, Turkey.
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38
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Landberg G, Ostlund H, Nielsen NH, Roos G, Emdin S, Burger AM, Seth A. Downregulation of the potential suppressor gene IGFBP-rP1 in human breast cancer is associated with inactivation of the retinoblastoma protein, cyclin E overexpression and increased proliferation in estrogen receptor negative tumors. Oncogene 2001; 20:3497-505. [PMID: 11429696 DOI: 10.1038/sj.onc.1204471] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2001] [Revised: 03/01/2001] [Accepted: 03/15/2001] [Indexed: 12/31/2022]
Abstract
The complex insulin-like growth factor network of ligands, receptors and binding proteins has been shown to be disturbed in breast cancer. In addition to defects in proteins controlling cell cycle checkpoints, this type of aberrations could affect tumor growth and survival thereby influencing both tumor aggressiveness and potential response to treatments. We have previously identified the T1A12/mac25 protein, which is identical to the IGFBP-rP1, as a differentially expressed gene product in breast cancer cells compared with normal cells. Here we compare the expression of IGFBP-rP1 in 106 tumor samples with known status of cell cycle aberrations and other clinicopathological data. This was done using a tumor tissue section array system that allows for simultaneous immunohistochemical staining of all samples in parallel. Cytoplasmic staining of variable intensity was observed in most tumors, 15% lacked IGFBP-rP1 staining completely, 20% had weak staining, 32% intermediate and 33% showed strong staining. Low IGFBP-rP1 was associated with high cyclin E protein content, retinoblastoma protein (pRb) inactivation, low bcl-2 protein, poorly differentiated tumors and higher stage. There was a significantly impaired prognosis for patients with low IGFBP-rP1 protein tumors. Interestingly, IGFBP-rP1 showed an inverse association with proliferation (Ki-67%) in estrogen receptor negative tumors as well as in cyclin E high tumors suggesting a separate cell cycle regulatory function for IGFBP-rP1 independent of interaction with the estrogen receptor or the pRb pathway.
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MESH Headings
- Aneuploidy
- Biomarkers, Tumor/analysis
- Biomarkers, Tumor/genetics
- Breast Neoplasms/genetics
- Breast Neoplasms/pathology
- Carrier Proteins/analysis
- Carrier Proteins/genetics
- Cell Cycle/genetics
- Cell Cycle/physiology
- Cyclin D1/analysis
- Cyclin E/analysis
- Diploidy
- Female
- Gene Expression Regulation, Neoplastic
- Genes, Tumor Suppressor
- Genes, bcl-2
- Genes, erbB-2
- Genes, p53
- Humans
- Immunohistochemistry
- Insulin-Like Growth Factor Binding Proteins
- Lymphatic Metastasis
- Menopause
- Neoplasm Invasiveness
- Neoplasm Staging
- Polymorphism, Single-Stranded Conformational
- Prognosis
- Receptors, Estrogen/analysis
- Receptors, Progesterone/analysis
- Retinoblastoma Protein/metabolism
- Telomerase/analysis
- Tumor Suppressor Protein p53/analysis
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Affiliation(s)
- G Landberg
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
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39
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Dietze EC, Yee L, Seewaldt VL. Suppression of pRB expression in normal human mammary epithelial cells is associated with resistance to all-trans-retinoic acid but not N-(4-hydroxylphenyl)-retinamide. Breast Cancer Res Treat 2001; 66:41-50. [PMID: 11368409 DOI: 10.1023/a:1010620600473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Despite the widespread clinical use of synthetic and naturally occurring retinoids, the down stream targets of retinoids have not been fully characterized. We observe that G(1/0)-phase arrest induced by all-trans-retinoic acid (ATRA) in normal human mammary epithelial cells (HMECs) is temporally associated with a significant decrease in the levels of hyperphosphorylated retinoblastoma protein (pRB). Suppression of pRB protein expression in HMECs by retroviral-mediated expression of the E7 protein of the human papillomavirus strain 16 (HPV-16) was associated with resistance to ATRA-mediated growth arrest but not to the synthetic retinoid N-(4-hydroxyphenyl) retinamide (4-HPR or fenretinide). 4-HPR but not ATRA induced apoptosis in HMECs independent of the level of pRB protein expression. These observations suggest that ATRA- but not 4-HPR-mediated growth arrest may be dependent on the coordinated expression of pRB and emphasize the chemotherapeutic potential of 4-HPR, particularly for suppressing growth of tumors lacking pRB function.
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Affiliation(s)
- E C Dietze
- Division of Medical Oncology, Duke University Medical Center, Durhlam, NC 27710, USA
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40
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Nielsen NH, Roos G, Emdin SO, Landberg G. Methylation of the p16(Ink4a) tumor suppressor gene 5'-CpG island in breast cancer. Cancer Lett 2001; 163:59-69. [PMID: 11163109 DOI: 10.1016/s0304-3835(00)00674-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methylation of the p16(Ink4a) tumor suppressor gene 5'CpG island was analyzed in 104 primary breast cancer specimens using Southern blotting and methylation specific polymerase chain reaction (PCR) (MSP). Eight and four tumors, respectively, showed methylation, and all MSP positive tumors were detected by Southern blotting. To investigate possible methylation not detectable by these methods, bisulphite genomic sequencing was performed in 220 clones from 14 selected tumors. Absent methylation or methylation of single CpG dinucleotides prevailed in all tumors, but of the MSP positive tumors, three contained alleles with methylation of 31 or 32 of the 32 analyzed CpG dinucleotides in the island. Partially methylated alleles were also observed. In a group with low p16(Ink4a) expression determined by Western blotting, four randomly selected tumors contained several identical clones with methylation of 15 CpG dinucleotides by bisulphite genomic sequencing but with a methylation pattern that did not support detection by either Southern blotting or MSP, increasing the potential significance of p16(Ink4a) methylation in breast cancer.
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Affiliation(s)
- N H Nielsen
- Department of Medical Biosciences, Umeå University, S-901 87 Umeå, Sweden
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41
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Foster JS, Henley DC, Bukovsky A, Seth P, Wimalasena J. Multifaceted regulation of cell cycle progression by estrogen: regulation of Cdk inhibitors and Cdc25A independent of cyclin D1-Cdk4 function. Mol Cell Biol 2001; 21:794-810. [PMID: 11154267 PMCID: PMC86671 DOI: 10.1128/mcb.21.3.794-810.2001] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2000] [Accepted: 11/09/2000] [Indexed: 11/20/2022] Open
Abstract
Estrogens induce proliferation of estrogen receptor (ER)-positive MCF-7 breast cancer cells by stimulating G(1)/S transition associated with increased cyclin D1 expression, activation of cyclin-dependent kinases (Cdks), and phosphorylation of the retinoblastoma protein (pRb). We have utilized blockade of cyclin D1-Cdk4 complex formation through adenovirus-mediated expression of p16(INK4a) to demonstrate that estrogen regulates Cdk inhibitor expression and expression of the Cdk-activating phosphatase Cdc25A independent of cyclin D1-Cdk4 function and cell cycle progression. Expression of p16(INK4a) inhibited G(1)/S transition induced in MCF-7 cells by 17-beta-estradiol (E(2)) with associated inhibition of both Cdk4- and Cdk2-associated kinase activities. Inhibition of Cdk2 activity was associated with delayed removal of Cdk-inhibitory activity in early G(1) and decreased cyclin A expression. Cdk-inhibitory activity and expression of both p21(Cip1) and p27(Kip1) was decreased, however, in both control and p16(INK4a)-expressing cells 20 h after estrogen treatment. Expression of Cdc25A mRNA and protein was induced by E(2) in control and p16(INK4a)-expressing MCF-7 cells; however, functional activity of Cdc25A was inhibited in cells expressing p16(INK4a). Inhibition of Cdc25A activity in p16(INK4a)-expressing cells was associated with depressed Cdk2 activity and was reversed in vivo and in vitro by active Cdk2. Transfection of MCF-7 cells with a dominant-negative Cdk2 construct inhibited the E(2)-dependent activation of ectopic Cdc25A. Supporting a role for Cdc25A in estrogen action, antisense CDC25A oligonucleotides inhibited estrogen-induced Cdk2 activation and DNA synthesis. In addition, inactive cyclin E-Cdk2 complexes from p16(INK4a)-expressing, estrogen-treated cells were activated in vitro by treatment with recombinant Cdc25A and in vivo in cells overexpressing Cdc25A. The results demonstrate that functional association of cyclin D1-Cdk4 complexes is required for Cdk2 activation in MCF-7 cells and that Cdk2 activity is, in turn, required for the in vivo activation of Cdc25A. These studies establish Cdc25A as a growth-promoting target of estrogen action and further indicate that estrogens independently regulate multiple components of the cell cycle machinery, including expression of p21(Cip1) and p27(Kip1).
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Affiliation(s)
- J S Foster
- Department of Obstetrics and Gynecology, Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, Tennessee 37920, USA
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42
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Maitra A, Roberts H, Weinberg AG, Geradts J. Loss of p16(INK4a) expression correlates with decreased survival in pediatric osteosarcomas. Int J Cancer 2001; 95:34-8. [PMID: 11241308 DOI: 10.1002/1097-0215(20010120)95:1<34::aid-ijc1006>3.0.co;2-v] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abnormalities of the G1 cell-cycle checkpoint are commonly reported in cancers at various anatomic sites. pRB, p16(INK4a) and cyclin D1 are critical G1-checkpoint proteins responsible for maintaining the balance of cellular proliferation. We examined a series of 38 pediatric osteosarcomas for abnormal expression of pRB, p16(INK4a) and cyclin D1 by immunohistochemical analysis of archival biopsy specimens. Overall, 17/38 (45%) osteosarcomas showed evidence of G1-checkpoint abrogation, including 11/38 (29%) with loss of pRB expression and 6/38 (16%) with loss of p16(INK4a) expression. Cyclin D1 over-expression was not detected. There was an inverse correlation between loss of pRB and p16(INK4a) expression (p = 0.07). pRB and p16(INK4a) abnormalities were independent of site of disease, presence of metastasis at diagnosis and percentage of tumor necrosis in the resection specimen. Clinical follow-up was available on all patients (median 31.6 months, range 5.9-116 months). Absence of p16(INK4a) expression significantly correlated with decreased survival in univariate analysis (p = 0.03), while loss of pRB expression did not affect survival. Immunohistochemical analysis of p16(INK4a) expression in pediatric osteosarcomas may be a useful adjunctive marker of prognosis.
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Affiliation(s)
- A Maitra
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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43
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Lane HA, Beuvink I, Motoyama AB, Daly JM, Neve RM, Hynes NE. ErbB2 potentiates breast tumor proliferation through modulation of p27(Kip1)-Cdk2 complex formation: receptor overexpression does not determine growth dependency. Mol Cell Biol 2000; 20:3210-23. [PMID: 10757805 PMCID: PMC85615 DOI: 10.1128/mcb.20.9.3210-3223.2000] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/1999] [Accepted: 02/03/2000] [Indexed: 11/20/2022] Open
Abstract
Overexpression of the ErbB2 receptor, a major component of the ErbB receptor signaling network, contributes to the development of a number of human cancers. ErbB2 presents itself, therefore, as a target for antibody-mediated therapies. In this respect, anti-ErbB2 monoclonal antibody 4D5 specifically inhibits the growth of tumor cells overexpressing ErbB2. We have analyzed the effect of 4D5-mediated ErbB2 inhibition on the cell cycle of the breast tumor cell line BT474. 4D5 treatment of BT474 cells resulted in a G(1) arrest, preceded by rapid dephosphorylation of ErbB2, inhibition of cytoplasmic signal transduction pathways, accumulation of the cyclin-dependent kinase inhibitor p27(Kip1), and inactivation of cyclin-Cdk2 complexes. Time courses demonstrated that 4D5 treatment redirects p27(Kip1) onto Cdk2 complexes, an event preceding increased p27(Kip1) expression; this correlates with the downregulation of c-Myc and D-type cyclins (proteins involved in p27(Kip1) sequestration) and the loss of p27(Kip1) from Cdk4 complexes. Similar events were observed in ErbB2-overexpressing SKBR3 cells, which exhibited reduced proliferation in response to 4D5 treatment. Here, p27(Kip1) redistribution resulted in partial Cdk2 inactivation, consistent with a G1 accumulation. Moreover, p27(Kip1) protein levels remained constant. Antisense-mediated inhibition of p27(Kip1) expression in 4D5-treated BT474 cells further demonstrated that in the absence of p27(Kip1) accumulation, p27(Kip1) redirection onto Cdk2 complexes is sufficient to inactivate Cdk2 and establish the G(1) block. These data suggest that ErbB2 overexpression leads to potentiation of cyclin E-Cdk2 activity through regulation of p27(Kip1) sequestration proteins, thus deregulating the G(1)/S transition. Moreover, through comparison with an ErbB2-overexpressing cell line insensitive to 4D5 treatment, we demonstrate the specificity of these cell cycle events and show that ErbB2 overexpression alone is insufficient to determine the cellular response to receptor inhibition.
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Affiliation(s)
- H A Lane
- Friedrich Miescher Institute, CH-4002 Basel, Switzerland.
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