Cyclin gene amplification and overexpression in breast and ovarian cancers: evidence for the selection of cyclin D1 in breast and cyclin E in ovarian tumors

Clinical Significance of Cyclin Expression Profiling in Ocular Surface Squamous Neoplasia

Ocular surface squamous neoplasia (OSSN) can recur, metastasize, and even cause death. Cyclins regulate the cell cycle progression at different phases and its dysregulation is associated with uncontrollable cell growth and malignant transformation of the cell. Overexpression of cyclin has been reported in various malignancies and is associated with poor prognosis. However, the role of cyclins in OSSN remains unexplored. This study has been designed to assess the prognostic significance of cyclin (cyclin B1, E1, and D1) immunoexpression in 100 OSSN patients. The targeted proteins demonstrated overexpression of cyclin B1, cyclin E1, and cyclin D1 in 55%, 37%, and 56% OSSN cases prospectively. A gradual and significant increase in the cyclin B1 (P=0.01) and cyclin D1 (P=0.005) expression was seen from Tis to the T4 category. Overexpression of cyclin B1 was associated with poor disease-free survival and worst prognosis in both early (P=0.03) as well as advanced T staged (P=0.038) OSSN patients. Overexpression of cyclin E1 was associated with worst disease-free survival (P=0.01) and poor prognosis in advanced stage OSSN patients. Our findings suggest that cyclin B1 and cyclin E1 have prognostic relevance in OSSN patients, and therefore are recommended for detecting high-risk category cases. A significant increase in the expression of cyclins from early to advanced stage indicates that cyclins play an important role in the pathogenesis of OSSN patients.

Prognostic and Predictive Value of CCND1/Cyclin D1 Amplification in Breast Cancer With a Focus on Postmenopausal Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Up to 80% of breast cancers (BCa) are estrogen receptor positive and current treatments target the estrogen receptor (endocrine therapies) and/or CDK4/6 (CDK4/6 inhibitors). CCND1 encodes the protein cyclin D1, responsible for regulation of G1 to S phase transition in the cell cycle. CCND1 amplification is common in BCa and contributes to increased cyclin D1 expression. As there are signalling interactions between cyclin D1 and the estrogen receptor, understanding the impact of CCND1 amplification on estrogen receptor positive patients' disease outcomes, is vital. This review aims to evaluate CCND1 amplification as a prognostic and predictive biomarker in BCa.

MATERIALS AND METHODS

Publications were retrieved from the databases: PubMed, MEDLINE, Embase and Cochrane library. Exclusion criteria were duplication, publication type, non-English language, in vitro and animal studies, not BCa, male BCa, premenopausal BCa, cohort size <35, CCND1 amplification not reported. Publications with cohort duplication, and inadequate recurrence free survival (RFS) and overall survival (OS) data, were also excluded. Included publications were assessed for Risk of Bias (RoB) using the Quality In Prognosis Studies tool. Statistical analyses (Inverse Variance and Mantel-Haenszel) were performed in Review Manager. The PROSPERO registration number is [CRD42020208179].

RESULTS

CCND1 amplification was significantly associated with positive estrogen receptor status (OR:1.70, 95% CI:1.19-2.43, p = 0.004) and cyclin D1 overexpression (OR: 5.64, 95% CI: 2.32-13.74, p=0.0001). CCND1 amplification was significantly associated with shorter RFS (OR: 1.64, 95% CI: 1.13-2.38, p = 0.009), and OS (OR: 1.51, 95% CI: 1.19-1.92, p = 0.0008) after removal of studies with a high RoB. In endocrine therapy treated patients specifically, CCND1 amplification predicted shorter RFS (HR: 2.59, 95% CI: 1.96-3.41, p < 0.00001) and OS (HR: 1.59, 95% CI: 1.00-2.49, p = 0.05) also after removal of studies with a high RoB.

CONCLUSION

While a lack of standardised approach for the detection of CCND1 amplification is to be considered as a limitation, CCND1 amplification was found to be prognostic of shorter RFS and OS in BCa. CCND1 amplification is also predictive of reduced RFS and OS in endocrine therapy treated patients specifically. With standardised methods and cut offs for the detection of CCND1 amplification, CCND1 amplification would have potential as a predictive biomarker in breast cancer patients.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42020208179.

Oncogenic and Tumor Suppressive Components of the Cell Cycle in Breast Cancer Progression and Prognosis

Cancer, a disease of inappropriate cell proliferation, is strongly interconnected with the cell cycle. All cancers consist of an abnormal accumulation of neoplastic cells, which are propagated toward uncontrolled cell division and proliferation in response to mitogenic signals. Mitogenic stimuli include genetic and epigenetic changes in cell cycle regulatory genes and other genes which regulate the cell cycle. This suggests that multiple, distinct pathways of genetic alterations lead to cancer development. Products of both oncogenes (including cyclin-dependent kinase (CDKs) and cyclins) and tumor suppressor genes (including cyclin-dependent kinase inhibitors) regulate cell cycle machinery and promote or suppress cell cycle progression, respectively. The identification of cyclins and CDKs help to explain and understand the molecular mechanisms of cell cycle machinery. During breast cancer tumorigenesis, cyclins A, B, C, D1, and E; cyclin-dependent kinase (CDKs); and CDK-inhibitor proteins p16, p21, p27, and p53 are known to play significant roles in cell cycle control and are tightly regulated in normal breast epithelial cells. Following mitogenic stimuli, these components are deregulated, which promotes neoplastic transformation of breast epithelial cells. Multiple studies implicate the roles of both types of components-oncogenic CDKs and cyclins, along with tumor-suppressing cyclin-dependent inhibitors-in breast cancer initiation and progression. Numerous clinical studies have confirmed that there is a prognostic significance for screening for these described components, regarding patient outcomes and their responses to therapy. The aim of this review article is to summarize the roles of oncogenic and tumor-suppressive components of the cell cycle in breast cancer progression and prognosis.

Coffee decoction enhances tamoxifen proapoptotic activity on MCF-7 cells

The consumption of coffee has been suggested to effectively enhance the therapeutic effects of tamoxifen against breast cancer; however, the underlying molecular mechanisms remain unclear. We herein attempted to clarify how coffee decoction exerts anti-cancer effects in cooperation with tamoxifen using the estrogen receptor α (ERα)-positive breast cancer cell line, MCF-7. The results obtained showed that coffee decoction down-regulated the expression of ERα, which was attributed to caffeine inhibiting its transcription. Coffee decoction cooperated with tamoxifen to induce cell-cycle arrest and apoptotic cell death, which may have been mediated by decreases in cyclin D1 expression and the activation of p53 tumor suppressor. The inclusion of caffeine in coffee decoction was essential, but not sufficient, to induce cell-cycle arrest and apoptotic cell death, suggesting the requirement of unknown compound(s) in coffee decoction to decrease cyclin D1 expression and activate apoptotic signaling cascades including p53. The activation of p53 through the cooperative effects of these unidentified component(s), caffeine, and tamoxifen appeared to be due to the suppression of the ERK and Akt pathways. Although the mechanisms by which the suppression of these pathways induces p53-mediated apoptotic cell death remain unclear, the combination of decaffeinated coffee, caffeine, and tamoxifen also caused cell-cycle arrest and apoptotic cell death, suggesting that unknown compound(s) present in decaffeinated coffee cooperate with caffeine and tamoxifen.

Expression of Cyclin D1 protein in residual tumor after neoadjuvant chemotherapy for breast cancer

PURPOSE

Hormone receptor (HR)-positive breast cancer (BC) shows a poor response to neoadjuvant chemotherapy (NACT). New treatment targets like the Cyclin D1-CDK4/CDK6 complex are promising adjuvant/post-neoadjuvant therapeutic strategies. Evaluating Cyclin D1 overexpression in residual tumor could recognize those patients that benefit most from such post-neoadjuvant treatment. In this study, we determined Cyclin D1 expression in residual BC after NACT. Secondary aims were to correlate Cyclin D1 expression levels with clinicopathological parameters and to assess its prognostic value after NACT.

METHODS

We retrospectively assessed the nuclear expression of Cyclin D1 on tissue microarrays with residual tumor from 284 patients treated in the neoadjuvant GeparTrio (n = 186) and GeparQuattro (n = 98) trials. Evaluation was performed with a standardized immunoreactive score (IRS) after selecting a cut-off value.

RESULTS

A high expression level (IRS ≥ 6) of Cyclin D1 was found in 37.3% of the assessed specimens. An increased Cyclin D1 expression was observed in HR-positive tumors, compared to HR-negative tumors (p = 0.02). Low Cyclin D1 levels correlated with clinical tumor stage 1-3 (p = 0.03). Among patients with HR-positive/Her2-negative tumors and high Cyclin D1 expression, a better disease-free survival (DFS) was graphically suggested, but not significant (p = 0.21).

CONCLUSION

Our study demonstrates a measurable nuclear expression of Cyclin D1 in post-neoadjuvant residual tumor tissue of HR-positive BC. Cyclin D1 expression was not prognostic for DFS after NACT. Our results and defined cut-off suggest that the marker can be used to stratify tumors according to protein expression levels. Based on this, a prospective evaluation is currently performed in the ongoing Penelope-B trial.

Tetrandrine and cancer - An overview on the molecular approach

Tetrandrine has been known in the treatment of tuberculosis, hyperglycemia, negative ionotropic and chronotropic effects on myocardium, malaria, cancer and fever since years together. It has been known that, tetrandrine could modulate multiple signaling molecules such as kinases of cell cycle and rat sarcoma (RAS) pathway along with proteins of tumor suppressor genes, autophagy related, β-catenins, caspases, and death receptors. Moreover, tetrandrine exhibited reversal of drug resistance by modulating P-glyco protein (P-gp) expression levels in different cancers which is an added advantage of this compound compared to other chemotherapy drugs. Though, bioavailability of tetrandrine is a limiting factor, the anticancer activity was observed in animal models without changing any pharmacokinetic parameters. In the present review, role of tetrandrine as kinase inhibitor, inducer of autophagy and caspase pathways and suppressor of RAS mediated cell proliferation were discussed along with inhibition of angiogenesis. It has also been discussed that how tetrandrine potentiate anticancer effect in different types of cancers by modulating multidrug resistance under in vitro and in vivo trials including the available literature on the clinical trials.

Cyclin D1 is significantly associated with stage of tumor and predicts poor survival in endometrial carcinoma patients

Cyclin D1 overexpression has been described to have oncogenic role and association with diagnosis, prognosis and survival in various tumors. This study will describe the immunohistochemical phenotype of cyclin D1, and investigate the correlation between these patterns of expression and clinicopathological parameters of endometrial carcinomas, to conclude the clinical relevance of cyclin D1 expression in the evolution of endometrial neoplasms. This study employed 101 endometrial tissue samples which include 71 endometrial carcinomas and thirty normal and benign endometrium cases. All these tissue samples were used in the assembly of tissue microarrays which have been utilized afterward in immunohistochemistry staining to detect cyclin D1 expression. Forty (56.3%) cases of endometrial carcinomas showed brown nuclear expression of cyclin D1 including 36 (61%) cases of endometrioid carcinomas, and 3 (33.3%) cases of serous carcinomas. Twenty three (76.6%) cases of control group demonstrated nuclear expression. High score cyclin D1 immunohistochemical staining has been significantly linked with patient age (P=0.0001). Large proportion of high score cyclin D1 immunohistochemical staining was observed in females who are <40years of age while high proportions of negative staining were observed in older age groups. Histologic type of tissue was also significantly related to cyclin D1 immunohistochemical staining (P-value=0.0001), high staining is more common in normal proliferative and secretory endometrium while serous carcinoma is more prevalent with negative staining. Stage of tumor was significantly associated with cyclin D1 immunohistochemical staining (P-value=0.029), proportion of stage III and IV are higher in negative cyclin D1 immunostaining. Significantly higher proportion of high score cyclin D1 immunostaining is observed in controls while higher proportion of negative cyclin D1 immunostaining is observed among carcinoma cases (P-value=0.0001). No significant associations between cyclin D1 immunohistochemical staining and grade, recurrence and alive status were observed. Significant different survival distributions were observed (P-value=0.011) and poor survival behavior was correlated with negative cyclin D1 immunohistochemical staining. In conclusion, greater frequency of cyclin D1 expression was revealed in normal endometrial tissues in comparison with carcinomas. The distribution pattern of cyclin D1 immunoexpression suggests poor prognoses in endometrial carcinoma patients.

The 'Pushmi-Pullyu' of DNA REPAIR: Clinical Synthetic Lethality

Maintenance of genomic integrity is critical for adaptive survival in the face of endogenous and exogenous environmental stress. The loss of stability and fidelity in the genome caused by cancer and cancer treatment provides therapeutic opportunities to leverage the critical balance between DNA injury and repair. Blocking repair and pushing damaged DNA through the cell cycle using therapeutic inhibitors exemplify the 'pushmi-pullyu' effect of disrupted DNA repair. DNA repair inhibitors (DNARi) can be separated into five biofunctional categories: sensors, mediators, transducers, effectors, and collaborators that recognize DNA damage, propagate injury DNA messages, regulate cell cycle checkpoints, and alter the microenvironment. The result is cancer therapeutics that takes advantage of clinical synthetic lethality, resulting in selective tumor cell kill. Here, we review recent considerations related to DNA repair and new DNARi agents and organize those findings to address future directions and clinical opportunities.

Parkin and mitophagy in cancer

Mitophagy, the selective engulfment and clearance of mitochondria, is essential for the homeostasis of a healthy network of functioning mitochondria and prevents excessive production of cytotoxic reactive oxygen species from damaged mitochondria. The mitochondrially targeted PTEN-induced kinase-1 (PINK1) and the E3 ubiquitin ligase Parkin are well-established synergistic mediators of the mitophagy of dysfunctional mitochondria. This pathway relies on the ubiquitination of a number of mitochondrial outer membrane substrates and subsequent docking of autophagy receptor proteins to selectively clear mitochondria. There are also alternate Parkin-independent mitophagy pathways mediated by BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 and Nip-3 like protein X as well as other effectors. There is increasing evidence that ablation of mitophagy accelerates a number of pathologies. Familial Parkinsonism is associated with loss-of-function mutations in PINK1 and Parkin. A growing number of studies have observed a correlation between impaired Parkin activity and enhanced cancer development, leading to the emerging concept that Parkin activity, or mitophagy in general, is a tumour suppression mechanism. This review examines the molecular mechanisms of mitophagy and highlights the potential links between Parkin and the hallmarks of cancer that may influence tumour development and progression.

PKCiota promotes ovarian tumor progression through deregulation of cyclin E

The high frequency of relapse of epithelial ovarian tumors treated with standard chemotherapy has highlighted the necessity to identify targeted therapies that can improve patient outcomes. The dynamic relationship between Cyclin E and PKCiota frequent overexpression in high-grade ovarian tumors poses a novel pathway for therapeutic investigation. We hypothesized that a PI3K dependent signaling pathway activating PKCiota perpetuates cyclin E deregulation during ovarian tumorigenesis. We observed a positive correlation between PKCiota and cyclin E in a panel of 19 ovarian cancer cell lines. Modulation of cyclin E had no effect on PKCiota knockdown/overexpression however PKCiota differentially regulated cyclin E expression. In the serous ovarian cancer cells (IGROV, OVCAR-3), shPKCiota decreased proliferation, caused a G1 arrest, and significantly prolonged overall survival in xenograft mouse models. In vitro shPKCiota decreased the ability of IGROV cells to grow under anchorage independent conditions and form aberrant acini, which was dependent upon Ad-cyclin E or Ad-LMW-E expression. RPPA analysis of PKCiota wild-type, catalytic active, dominant negative protein isoforms strengthened the association between phospho-PKCiota levels and PI3K pathway activation. Inhibitors of PI3K coordinately decreased phospho-PKCiota and Cyclin E protein levels. In conclusion, we have identified a PI3K/PKCiota/Cyclin E signaling pathway as a therapeutic target during ovarian tumorigenesis.

Histo-genomic stratification reveals the frequent amplification/overexpression of CCNE1 and BRD4 genes in non-BRCAness high grade ovarian carcinoma

The treatment of epithelial ovarian cancer (EOC) is narrowly focused despite the heterogeneity of this disease in which outcomes remain poor. To stratify EOC patients for targeted therapy, we developed an approach integrating expression and genomic analyses including the BRCAness status. Gene expression and genomic profiling were used to identify genes recurrently (>5%) amplified and overexpressed in 105 EOC. The LST (Large-scale State Transition) genomic signature of BRCAness was applied to define molecular subgroups of EOC. Amplified/overexpressed genes clustered mainly in 3q, 8q, 19p and 19q. These changes were generally found mutually exclusive. In the 85 patients for which the genomic signature could be determined, genomic BRCAness was found in 52 cases (61.1%) and non-BRCAness in 33 (38.8%). A striking mutual exclusivity was observed between BRCAness and amplification/overexpression data. Whereas 3q and 8q alterations were preferentially observed in BRCAness EOC, most alterations on chromosome 19 were in non-BRCAness cases. CCNE1 (19q12) and BRD4 (19p13.1) amplification/overexpression was found in 19/33 (57.5%) of non-BRCAness cases. Such disequilibrium was also found in the TCGA EOC data set used for validation. Potential target genes are frequently amplified/overexpressed in non-BRCAness EOC. We report that BRD4, already identified as a target in several tumor models, is a new potential target in high grade non-BRCAness ovarian carcinoma.

Cooperation of DLC1 and CDK6 affects breast cancer clinical outcome

Low DLC1 expression is found to frequently co-occur with aberrant expression of cell cycle genes including CDK6 in human lung and colon cancer. Here, we explore the influence of the synergistic effect of DLC1 and CDK6 on human breast cancer survival at the genetic, transcriptional, and translational levels. We found that high DLC1 and low CDK6 expression are associated with good prognosis. The DLC1 intronic SNP rs561681 is found to fit a recessive model, complying with the tumor suppressive role of DLC1. The heterozygote of the DLC1 SNP is found to increase the hazard when the CDK6 intronic SNP rs3731343 is rare homozygous, and it becomes protective when rs3731343 is common homozygous. We propose that DLC1 expression is the lowest in patients harboring the rare homozygote of rs561681 and functional DLC1 is the lowest when rs561681 is heterozygous and rs3731343 is rare homozygous. We are the first to report such synergistic effects of DLC1 and CDK6 on breast cancer survival at the transcriptional level, the overdominant model fitted by the SNP pair, and the dominant negative effect at the translational level. These findings link the germline genetic polymorphisms and synergistic effect of DLC1 and CDK6 with breast cancer progression, which provide the basis for experimentally elucidating the mechanisms driving differential tumor progression and avail in tailoring the clinical treatments for such patients based on their genetic susceptibility.

Cell cycle regulators cyclin D1 and CDK4/6 have estrogen receptor-dependent divergent functions in breast cancer migration and stem cell-like activity

Cyclin D1 and its binding partners CDK4/6 are essential regulators of cell cycle progression and are implicated in cancer progression. Our aim was to investigate a potential regulatory role of these proteins in other essential tumor biological characteristics. Using a panel of breast cancer cell lines and primary human breast cancer samples, we have demonstrated the importance of these cell cycle regulators in both migration and stem-like cell activity. siRNA was used to target cyclin D1 and CDK4/6 expression, having opposing effects on both migration and stem-like cell activity dependent upon estrogen receptor (ER) expression. Inhibition of cyclin D1 or CDK4/6 increases or decreases migration and stem-like cell activity in ER-ve (ER-negative) and ER+ve (ER-positive) breast cancer, respectively. Furthermore, overexpressed cyclin D1 caused decreased migration and stem-like cell activity in ER-ve cells while increasing activity in ER+ve breast cancer cells. Treatment of breast cancer cells with inhibitors of cyclin D1 and CDK4/6 (Flavopiridol/PD0332991), currently in clinical trials, mimicked the effects observed with siRNA treatment. Re-expression of ER in two ER-ve cell lines was sufficient to overcome the effects of either siRNA or clinical inhibitors of cyclin D1 and CDK4/6.   In conclusion, cyclin D1 and CDK4/6 have alternate roles in regulation of migration and stem-like cell activity. Furthermore, these effects are highly dependent upon expression of ER. The significance of these results adds to our general understanding of cancer biology but, most importantly, could be used diagnostically to predict treatment response to cell cycle inhibition in breast cancer.

Genetic polymorphisms in AURKA, BRCA1, CCNE1 and CDK2 are associated with ovarian cancer susceptibility among Chinese Han women

INTRODUCTION

Centrosome aberrations and cell-cycle deregulation have important implications for ovarian cancer development. The AURKA, BRCA1, CCNE1 and CDK2 genes play pivotal roles in centrosome duplication and cell-cycle regulation.

METHODS

Using a haplotype-based analysis, this study aimed to investigate whether genetic polymorphisms in these four genes may contribute to ovarian cancer susceptibility. A total of 22 single nucleotide polymorphisms (SNPs) in these four genes were genotyped in 287 cases of ovarian serous cystadenocarcinomas and 618 age-matched cancer-free controls from the Chinese Han population, and then haplotype blocks were reconstructed according to our genotyping data and linkage disequilibrium (LD) status of these SNPs.

RESULTS

For AURKA, we found that haplotype GA [rs6064391 (T→G)+rs911162 (G→A)] was strongly associated with decreased ovarian cancer risk (adjusted OR=0.31, 95% CI=0.15-0.63, P=0.0012). For BRCA1, we found that haplotype CGTAG was associated with decreased ovarian cancer risk (adjusted OR=0.64, 95% CI=0.41-0.98, P=0.0417). Moreover, women harboring homozygous GA/CGTAG haplotypes showed the lowest risk (OR=0.12, 95% CI=0.02-0.94, P=0.0438). In CCNE1, the SNPs rs3218035 and rs3218042 were significantly associated with increased ovarian cancer risk (rs3218035: adjusted OR=5.20, 95% CI=1.85-14.52, P=0.0017; rs3218042: adjusted OR=4.98, 95% CI=1.75-14.19, P=0.0027). For CDK2, no significant association was found.

CONCLUSIONS

This study indicates that genetic polymorphisms of AURKA, BRCA1 and CCNE1 may affect ovarian cancer susceptibility in Chinese Han women.

Mammalian interphase cdks: dispensable master regulators of the cell cycle

Cyclin-dependent kinases (Cdks) drive cell cycle progression in all eukaryotes. Yeasts have a single major Cdk that mediates distinct cell cycle transitions via association with different cyclins. The closest homolog in mammals, Cdk1, drives mitosis. Mammals have additional Cdks-Cdk2, Cdk4, and Cdk6-that represent the major Cdks activated during interphase (iCdks). A large body of evidence has accrued that suggests that activation of iCdks dictates progression though interphase. In apparent contradiction, deficiency in each individual iCdk, respectively, in knockout mice proved to be compatible with live birth and in some instances fertility. Moreover, murine embryos could be derived with Cdk1 as the only functional Cdk. Thus, none of the iCdks is strictly essential for mammalian cell cycle progression, raising the possibility that Cdk1 is the dominant regulator in interphase. However, an absence of iCdks has been accompanied by major shifts in cyclin association to Cdk1, suggesting gain in function. After considerable tweaking, a chemical genetic approach has recently been able to examine the impact of acute inhibition of Cdk2 activity without marked distortion of cyclin/Cdk complex formation. The results suggest that, when expressed at its normal levels, Cdk2 performs essential roles in driving human cells into S phase and maintaining genomic stability. These new findings appear to have restored order to the cell cycle field, bringing it full circle to the view that iCdks indeed play important roles. They also underscore the caveat in knockdown and knockout approaches that protein underexpression can significantly perturb a protein interaction network. We discuss the implications of the new synthesis for future cell cycle studies and anti-Cdk-based therapy of cancer and other diseases.

Rsf-1, a chromatin remodelling protein, interacts with cyclin E1 and promotes tumour development

Chromosome 11q13.5 containing RSF1 (HBXAP), a gene involved in chromatin remodelling, is amplified in several human cancers including ovarian carcinoma. Our previous studies demonstrated requirement of Rsf-1 for cell survival in cancer cells, which contributed to tumour progression; however, its role in tumourigenesis has not yet been elucidated. In this study, we co-immunoprecipitated proteins with Rsf-1 followed by nanoelectrospray mass spectrometry and identified cyclin E1, besides SNF2H, as one of the major Rsf-1 interacting proteins. Like RSF1, CCNE1 is frequently amplified in ovarian cancer, and both Rsf-1 and cyclin E1 were found co-up-regulated in ovarian cancer tissues. Ectopic expression of Rsf-1 and cyclin E1 in non-tumourigenic TP53(mut) RK3E cells led to an increase in cellular proliferation and tumour formation by activating cyclin E1-associated kinase (CDK2). Tumourigenesis was not detected if either cyclin E1 or Rsf-1 was expressed, or they were expressed in a TP53(wt) background. Domain mapping showed that cyclin E1 interacted with the first 441 amino acids of Rsf-1. Ectopic expression of this truncated domain significantly suppressed G1/S-phase transition, cellular proliferation, and tumour formation of RK3E-p53(R175H) /Rsf-1/cyclin E1 cells. The above findings suggest that Rsf-1 interacts and collaborates with cyclin E1 in neoplastic transformation and TP53 mutations are a prerequisite for tumour-promoting functions of the RSF/cyclin E1 complex.

Distinct expression pattern and post-transcriptional regulation of cell cycle genes in the glandular epithelia of avian ovarian carcinomas

The cell cycle system is controlled in a timely manner by three groups of cyclins, cyclin dependent kinases and cyclin dependent kinase inhibitors. Abnormal alterations of cell cycle regulatory mechanisms are a common feature of many diseases including numerous tumor types such as ovarian cancer. Although a variety of cell cycle regulatory genes are well known in mammalian species including human and mice, they are not well studied in avian species, especially in laying hens which are recognized as an excellent animal model for research relevant to human ovarian carcinogenesis. Therefore, in the present study, we focused on comparative expression and regulation of expression of candidate genes which might be involved in the cell cycle program in surface epithelial ovarian cancer in laying hens. Our current results indicate that expression levels of cell cycle gene transcripts are greater in cancerous as compared to normal ovaries. In particular, cyclin A2 (CCNA2), CCND1, CCND2, CCND3, CCNE2, cyclin dependent kinase 1 (CDK1), CDK3, CDK5, cyclin dependent kinases inhibitor 1A (CDKN1A) and CDKN1B were upregulated predominantly in the glandular epithelia of cancerous ovaries from laying hens. Further, several microRNAs (miRs), specifically miR-1798, miR-1699, miR-223 and miR-1744 were discovered to influence expression of CCND1, CCNE2, CDK1, and CDK3 mRNAs, respectively, via their 3′-UTR which suggests that post-transcriptional regulation of gene expression influences their expression in laying hens. Moreover, miR-1626 influenced CDKN1A expression and miR-222, miR-1787 and miR-1812 regulated CDKN1B expression via their 3′-UTR regions. Collectively, results of the present study demonstrate increased expression of cell cycle-related genes in cancerous ovaries of laying hens and indicate that expression of these genes is post-transcriptionally regulated by specific microRNAs.

Biphasic dose-dependent effect of lithium chloride on survival of human hormone-dependent breast cancer cells (MCF-7)

Lithium, the first element of Group I in the periodic system, is used to treat bipolar psychiatric disorders. Lithium chloride (LiCl) is a selective inhibitor of glycogen synthase kinase-3β (GSK-3β), a serine/threonine kinase that regulates many cellular processes, in addition to its role in the regulation of glycogen synthase. GSK-3β is emerged as a promising drug target for various neurological diseases, type-2 diabetes, cancer, and inflammation. Several works have demonstrated that lithium can either inhibit or stimulate growth of normal and cancer cells. Hence, the present study is focused to analyze the underlying mechanisms that dictate the biphasic oncogenic properties of LiCl. In the current study, we have investigated the dose-dependent effects of LiCl on human breast cancer cells (MCF-7) by assessing the consequences on cytotoxicity and protein expressions of signaling molecules crucial for the maintenance of cell survival. The results showed breast cancer cells respond in a diverse manner to LiCl, i.e., at lower concentrations (1, 5, and 10 mM), LiCl induces cell survival by inhibiting apoptosis through regulation of GSK-3β, caspase-2, Bax, and cleaved caspase-7 and by activating anti-apoptotic proteins (Akt, β-catenin, Bcl-2, and cyclin D1). In contrast, at high concentrations (50 and 100 mM), it induces apoptosis by reversing these effects. Moreover, LiCl also alters the sodium and potassium levels thereby altering the membrane potential of MCF-7 cells. Thus it is inferred that LiCl exerts a dose-dependent biphasic effect on breast cancer cells (MCF-7) by altering the apoptotic/anti-apoptotic balance.

Prognostic biomarkers in ovarian cancer

Epithelial ovarian cancer (EOC) remains the most lethal gynecological malignancy despite several decades of progress in diagnosis and treatment. Taking advantage of the robust development of discovery and utility of prognostic biomarkers, clinicians and researchers are developing personalized and targeted treatment strategies. This review encompasses recently discovered biomarkers of ovarian cancer, the utility of published prognostic biomarkers for EOC (especially biomarkers related to angiogenesis and key signaling pathways), and their integration into clinical practice.

Limited prognostic value of tissue protein expression levels of cyclin E in Danish ovarian cancer patients: from the Danish 'MALOVA' ovarian cancer study

The primary objective of this study was to assess the expression of cyclin E in tumour tissues from 661 patients with epithelial ovarian tumours. The second was to evaluate whether cyclin E tissue expression levels correlate with clinico-pathological parameters and prognosis of the disease. Using tissue arrays (TA), we analysed the cyclin E expression levels in tissues from 168 women with borderline ovarian tumours (BOT) (147 stage I, 4 stage II, 17 stage III) and 493 Ovarian cancer (OC) patients (127 stage I, 45 stage II, 276 stage III, 45 stage IV). Using a 10% cut-off level for cyclin E overexpression, 20% of the BOTs were positive with a higher proportion of serous than mucinous tumours. Sixty-two per cent of the OCs were positive for cyclin E expression with the highest percentage found in clear cell carcinomas. Results based on univariate and multivariate survival analyses with a 10% cut-off value showed that cyclin E had no independent prognostic value. In conclusion, we found cyclin E expression in tumour tissue to be of limited prognostic value to Danish OC patients.

Breaking the cycle: An insight into the role of ERα in eukaryotic cell cycles

There have been numerous reviews written to date on estrogen receptor (ER), focusing on topics such as its role in the etiology of breast cancer, its mode of regulation, its role as a transcriptional activator and how to target it therapeutically, just to name a few. One reason for so much attention on this nuclear receptor is that it acts not only as a prognostic marker, but also as a target for therapy. However, a relatively undiscovered area in the literature regarding ER is how its activity in the presence and absence of ligand affects its role in proliferation and cell cycle transition. In this review, we provide a brief overview of ER signaling, ligand dependent and independent, genomic and non-genomic, and how these signaling events affect the role of ER in the mammalian cell cycle.

Inherited and acquired alterations in development of breast cancer

Breast cancer is the most common cancer among women, accounting for about 30% of all cancers. In contrast, breast cancer is a rare disease in men, accounting for less than 1% of all cancers. Up to 10% of all breast cancers are hereditary forms, caused by inherited germ-line mutations in "high-penetrance," "moderate-penetrance," and "low-penetrance" breast cancer susceptibility genes. The remaining 90% of breast cancers are due to acquired somatic genetic and epigenetic alterations. A heterogeneous set of somatic alterations, including mutations and gene amplification, are reported to be involved in the etiology of breast cancer. Promoter hypermethylation of genes involved in DNA repair and hormone-mediated cell signaling, as well as altered expression of micro RNAs predicted to regulate key breast cancer genes, play an equally important role as genetic factors in development of breast cancer. Elucidation of the inherited and acquired genetic and epigenetic alterations involved in breast cancer may not only clarify molecular pathways involved in the development and progression of breast cancer itself, but may also have an important clinical and therapeutic impact on improving the management of patients with the disease.

Down-regulation of the oncogene cyclin D1 increases migratory capacity in breast cancer and is linked to unfavorable prognostic features

The oncogene cyclin D1 is highly expressed in many breast cancers and, despite its proliferation-activating properties, it has been linked to a less malignant phenotype. To clarify this observation, we focused on two key components of malignant behavior, migration and proliferation, and observed that quiescent G(0)/G(1) cells display an increased migratory capacity compared to cycling cells. We also found that the down-regulation of cyclin D1 in actively cycling cells significantly increased migration while also decreasing proliferation. When analyzing a large set of premenopausal breast cancers, we observed an inverse proliferation-independent link between cyclin D1 and tumor size and recurrence, suggesting that this protein might abrogate infiltrative malignant behavior in vivo. Finally, gene expression analysis after cyclin D1 down-regulation by siRNA confirmed changes in processes associated with migration and enrichment of our gene set in a metastatic poor prognosis signature. This novel function of cyclin D1 illustrates the interplay between tumor proliferation and migration and may explain the attenuation of malignant behavior in breast cancers with high cyclin D1 levels.

A multilevel data integration resource for breast cancer study

BACKGROUND

Breast cancer is one of the most common cancer types. Due to the complexity of this disease, it is important to face its study with an integrated and multilevel approach, from genes, transcripts and proteins to molecular networks, cell populations and tissues. According to the systems biology perspective, the biological functions arise from complex networks: in this context, concepts like molecular pathways, protein-protein interactions (PPIs), mathematical models and ontologies play an important role for dissecting such complexity.

RESULTS

In this work we present the Genes-to-Systems Breast Cancer (G2SBC) Database, a resource which integrates data about genes, transcripts and proteins reported in literature as altered in breast cancer cells. Beside the data integration, we provide an ontology based query system and analysis tools related to intracellular pathways, PPIs, protein structure and systems modelling, in order to facilitate the study of breast cancer using a multilevel perspective. The resource is available at the URL http://www.itb.cnr.it/breastcancer.

CONCLUSIONS

The G2SBC Database represents a systems biology oriented data integration approach devoted to breast cancer. By means of the analysis capabilities provided by the web interface, it is possible to overcome the limits of reductionist resources, enabling predictions that can lead to new experiments.

Serous tubal intraepithelial carcinoma upregulates markers associated with high-grade serous carcinomas including Rsf-1 (HBXAP), cyclin E and fatty acid synthase

Serous tubal intraepithelial carcinoma (STIC) has been proposed as a precursor for many pelvic high-grade serous carcinomas. Our previous analysis of the ovarian cancer genome identified several genes with oncogenic potential that are amplified and/or overexpressed in the majority of high-grade serous carcinomas. Determining whether these genes are upregulated in STICs is important in further elucidating the relationship of STICs to high-grade serous carcinomas and is fundamental in understanding the molecular pathogenesis of high-grade serous carcinomas. In this study, 37 morphologically defined STICs were obtained from 23 patients with stage IIIC/IV high-grade serous carcinomas. Both STICs and the high-grade serous carcinomas were analyzed for expression of Rsf-1 (HBXAP), cyclin E, fatty acid synthase (FASN) and mucin-4. In addition, they were examined for expression of established markers including p53, Ki-67 and p16. We found that diffuse nuclear p53 and p16 immunoreactivity was observed in 27 (75%) of 36 and 18 (55%) of 33 STICs, respectively, whereas an elevated Ki-67 labeling index (>or=10%) was detected in 29 (78%) of 37 STICs. Cyclin E nuclear staining was seen in 24 (77%) of 35 STICs, whereas normal tubal epithelial cells were all negative. Increased Rsf-1 and FASN immunoreactivity occurred in 63%, and 62% of STICs, respectively, compared with adjacent normal-appearing tubal epithelium. Interestingly, only one STIC showed increased mucin-4 immunoreactivity. Carcinomas, when compared with STICs, overexpressed p16, Rsf-1, cyclin E and FASN in a higher proportion of cases. In conclusion, STICs express several markers including Rsf-1, cyclin E and FASN in high-grade serous carcinomas. In contrast, mucin-4 immunoreactivity either did not change or was reduced in most STICs. These results suggest that overexpression of Rsf-1, cyclin E and FASN occurs early in tumor progression.

Gene expression profiling supports the hypothesis that human ovarian surface epithelia are multipotent and capable of serving as ovarian cancer initiating cells

BACKGROUND

Accumulating evidence suggests that somatic stem cells undergo mutagenic transformation into cancer initiating cells. The serous subtype of ovarian adenocarcinoma in humans has been hypothesized to arise from at least two possible classes of progenitor cells: the ovarian surface epithelia (OSE) and/or an as yet undefined class of progenitor cells residing in the distal end of the fallopian tube.

METHODS

Comparative gene expression profiling analyses were carried out on OSE removed from the surface of normal human ovaries and ovarian cancer epithelial cells (CEPI) isolated by laser capture micro-dissection (LCM) from human serous papillary ovarian adenocarcinomas. The results of the gene expression analyses were randomly confirmed in paraffin embedded tissues from ovarian adenocarcinoma of serous subtype and non-neoplastic ovarian tissues using immunohistochemistry. Differentially expressed genes were analyzed using gene ontology, molecular pathway, and gene set enrichment analysis algorithms.

RESULTS

Consistent with multipotent capacity, genes in pathways previously associated with adult stem cell maintenance are highly expressed in ovarian surface epithelia and are not expressed or expressed at very low levels in serous ovarian adenocarcinoma. Among the over 2000 genes that are significantly differentially expressed, a number of pathways and novel pathway interactions are identified that may contribute to ovarian adenocarcinoma development.

CONCLUSIONS

Our results are consistent with the hypothesis that human ovarian surface epithelia are multipotent and capable of serving as the origin of ovarian adenocarcinoma. While our findings do not rule out the possibility that ovarian cancers may also arise from other sources, they are inconsistent with claims that ovarian surface epithelia cannot serve as the origin of ovarian cancer initiating cells.

Somatic mutations of the Parkinson's disease-associated gene PARK2 in glioblastoma and other human malignancies

Mutation of the gene PARK2, which encodes an E3 ubiquitin ligase, is the most common cause of early-onset Parkinson's disease. In a search for multisite tumor suppressors, we identified PARK2 as a frequently targeted gene on chromosome 6q25.2-q27 in cancer. Here we describe inactivating somatic mutations and frequent intragenic deletions of PARK2 in human malignancies. The PARK2 mutations in cancer occur in the same domains, and sometimes at the same residues, as the germline mutations causing familial Parkinson's disease. Cancer-specific mutations abrogate the growth-suppressive effects of the PARK2 protein. PARK2 mutations in cancer decrease PARK2's E3 ligase activity, compromising its ability to ubiquitinate cyclin E and resulting in mitotic instability. These data strongly point to PARK2 as a tumor suppressor on 6q25.2-q27. Thus, PARK2, a gene that causes neuronal dysfunction when mutated in the germline, may instead contribute to oncogenesis when altered in non-neuronal somatic cells.

Expression levels of p18INK4C modify the cellular efficacy of cyclin-dependent kinase inhibitors via regulation of Mcl-1 expression in tumor cell lines

Because cyclin-dependent kinases (CDK) play a pivotal role in cancer progression, the development of CDK inhibitors has attracted attention in antitumor therapy. However, despite significant preclinical and clinical developments, CDK inhibition biomarkers for predicting efficacy against certain cancers in individual patients have not been identified. Here, we characterized a macrocyclic quinoxalin-2-one CDK inhibitor, compound A, and identified a gene biomarker for predicting its efficacy. Compound A showed 100-fold selectivity for CDK family proteins over other kinases and inhibited both E2F transcriptional activity and RNA polymerase II phosphorylation. Compound A treatment resulted in decreased proliferation in various tumor cell lines; however, the apoptosis induction rate differed significantly among the cell lines examined, which was consistent with roscovitine. By comparing the mRNA expression profiles of sensitive and resistant cell lines, we found that expression levels of an endogenous CDK inhibitor, p18(INK4C), showed a strong negative correlation to the sensitivity. In fact, p18 status was correlated with the response to CDK inhibitor in an independent data set of multiple myeloma cell lines and silencing p18 expression increased the susceptibility of resistant cells to CDK inhibitors. The analysis of molecular mechanisms revealed that cells with lowered p18 had aberrant CDK6 and E2F activities, which resulted in a transcriptional down-regulation of Mcl-1, a key molecule associated with flavopiridol-induced apoptosis, thereby leading to susceptibility to therapeutic intervention with CDK inhibitors. These results identified a molecular basis for CDK inhibitors to exert an antitumor effect in p18-deficient cancers and support the clinical use of CDK inhibitors.

Myofibroblastic sarcoma vs nodular fasciitis: a comparative study of chromosomal imbalances

We investigated the molecular cytogenetic features in myofibroblastic sarcoma (MS) to gain insight into the nature of the controversial entity. DNA copy number changes were analyzed by comparative genomic hybridization in 29 cases of MS and 5 cases of nodular fasciitis. The characteristic chromosomal imbalances in MS were gains at 1p11 --> p36.3 (19/29 [66%]), 12p12.2 --> p13.2 (13/29 [45%]), 5p13.2 --> p15.3 (9/29 [31%]), and chromosome 22 (8/29 [28%]) and loss at 15q25 --> q26.2 (7/29 [24%]). In contrast, only 1 of 5 cases of nodular fasciitis showed genetic aberrations. The average number of aberrations in nodular fasciitis (0.4) was significantly lower than that in MS (5.4). Thus, MS displayed complex DNA copy number changes and shared no range of common chromosomal abnormality with nodular fasciitis, indicating that distinct genetic pathways may be involved in the development of these entities.

Altered subcellular localization of tumor-specific cyclin E isoforms affects cyclin-dependent kinase 2 complex formation and proteasomal regulation

In tumors, alternative translation and posttranslational proteolytic cleavage of full-length cyclin E (EL) produces tumorigenic low molecular weight cyclin E (LMW-E) isoforms that lack a portion of the EL amino-terminus containing a nuclear localization sequence. Therefore, we hypothesized that LMW-E isoforms have altered subcellular localization. To explore our hypothesis, we compared EL versus LMW-E localization in cell lysates and in vivo using fractionation and protein complementation assays. Our results reveal that LMW-E isoforms preferentially accumulate in the cytoplasm where they bind the cyclin E kinase partner, cyclin-dependent kinase 2 (Cdk2), and have associated kinase activity. The nuclear ubiquitin ligase Fbw7 targets Cdk2-bound cyclin E for degradation; thus, we examined if altered subcellular localization affected LMW-E degradation. We found that cytoplasmic LMW-E/Cdk2 was less susceptible to Fbw7-mediated degradation. One implication of our findings is that altered LMW-E and LMW-E/Cdk2 subcellular localization may lead to aberrant LMW-E protein interactions, regulation, and activity, ultimately contributing to LMW-E tumorigenicity.

New diagnostic and molecular characteristics of malignant mesothelioma

Malignant mesothelioma is a primary cancer of the serosal cavities, an anatomic site that is also frequently affected by metastatic disease, predominantly from primary carcinomas of the lung, breast, and ovary. Advances in immunohistochemistry have resulted in improved diagnostic sensitivity and specificity in the differential diagnosis between metastatic adenocarcinoma and malignant mesothelioma in both cytological and histological material. Recently, the author's group applied high throughput technology to the identification of new markers that may aid in differentiating malignant mesothelioma from ovarian and peritoneal serous carcinoma, tumors with closely related histogenesis and antigenic profile. In addition to the improved tools available for serosal cancer diagnosis, knowledge regarding the biology of malignant mesothelioma has been accumulating in recent years. This review presents current data regarding the diagnostic and biological aspects of malignant mesothelioma.

Estrogen receptor gene amplification occurs rarely in ovarian cancer

Amplification of the gene encoding estrogen receptor-alpha occurs in about 20% of breast cancers and is an important mechanism for estrogen receptor overexpression in this tumor type. In ovarian cancer, overexpression of estrogen receptor protein has been described in more than two thirds of cases. To study a potential role of estrogen receptor-alpha gene amplification for estrogen receptor overexpression in ovarian cancer, a tumor tissue microarray containing 428 ovarian cancers was analyzed by fluorescence in situ hybridization for estrogen receptor-alpha gene amplification and immunohistochemistry for estrogen receptor expression. The estrogen receptor-alpha gene status was successfully determined in 243 of 428 arrayed cancers. Estrogen receptor gene amplification was found in 5 of 243 (2%) of tumors. Amplification levels were usually low, with 4-8 estrogen receptor-alpha gene copies. However, one case had a high-level amplification, with more than 30 estrogen receptor-alpha gene copies. All five amplified tumors were estrogen receptor positive, with 3 of 5 tumors showing highest (Allred score, 7-8) estrogen receptor levels. The data demonstrate that estrogen receptor-alpha amplification occurs only rarely in ovarian cancer.

Serum and tissue biomarkers as predictive and prognostic variables in epithelial ovarian cancer

Tumour stage, residual disease after initial surgery, histological type and tumour grade are the most important clinical-pathological factors related to the clinical outcome of patients with epithelial ovarian cancer. In the last years, several investigations have assessed different biological variables in sera and in tissue samples from patients with this malignancy in order to detect biomarkers able to reflect either the response to chemotherapy or survival. The present paper reviewed the literature data about the predictive or prognostic relevance of serum CA 125, soluble cytokeratin fragments, serum human kallikreins, serum cytokines, serum vascular endothelial growth factor and plasma d-dimer as well as of tissue expression of cell cycle- and apoptosis-regulatory proteins, human telomerase reverse transcriptase, membrane tyrosine kinase receptors and matrix metalloproteinases. A next future microarray technology will hopefully offer interesting perspectives of translational research for the identification of novel predictive and prognostic biomarkers for epithelial ovarian cancer.

Amplification of 11q13 in ovarian carcinoma

Amplification at the 11q13 locus is commonly observed in breast, ovarian, head and neck, oral, and esophageal cancer. Studies of this region led to the identification of multiple amplicons containing several potential oncogenes including EMSY, PAK1, RSF1, and GAB2. Here, we investigate the amplification of the above four genes and their prognostic significance in histologically and clinically defined subsets of ovarian cancer. Amplification of all four genes was assessed by fluorescent in situ hybridization in tissue microarrays containing 538 clinically annotated ovarian carcinomas with 12 years of follow-up data. Overall, for the entire cohort, EMSY was amplified in 44 (16%) of 269 cases, PAK1 was amplified in 38 (15%) of 255 cases, RSF1 was amplified in 37 (12%) of 310 cases, and GAB2 was amplified in 41 (16%) of 255 cases. Amplification of EMSY, PAK1, RSF1, and GAB2 were all highly correlated with each other and with a serous histology. Univariate survival analysis showed that tumors with EMSY and RSF1 amplification were associated with a significantly worse outcome. A molecular inversion probe array was then used to study the 11q13 amplicon in 33 high grade serous carcinomas. The core of the amplicon mapped to a 6-Mb region encompassing EMSY, PAK1, RSF1, and GAB2. However, a second more telomeric amplicon was also observed for which no candidate genes have been identified. In summary, amplification of these four putative oncogenes from 11q13 in early ovarian cancer is associated with a serous histology and in the case of EMSY and RSF1 a poor outcome. These findings support the hypothesis that the11q13 amplicon in ovarian cancer is likely driven by a cassette of genes rather than by a single oncogene. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.

Alteration of cell-cycle regulation in epithelial ovarian cancer

In spite of the clinical importance of epithelial ovarian cancer (EOC), little is known about the pathobiology of its precursor lesions and progression. Regulatory mechanisms of the cell cycle are mainly composed of cyclins, cyclin-dependent kinases (CDK), and CDK inhibitors. Alteration of these mechanisms results in uncontrolled cell proliferation, which is a distinctive feature of human cancers. This review describes the current state of knowledge about the alterations of cell-cycle regulations in the context of p16-cyclin D1-CDK4/6-pRb pathway, p21-p27-cyclin E-CDK2 pathway, p14-MDM2-p53 pathway, and ATM-Chk2-CDC25 pathway, respectively. Recent evidence suggests that ovarian cancer is a heterogenous group of neoplasms with several different histologic types, each with its own underlying molecular genetic mechanism. Therefore, expression of cell cycle regulatory proteins should be tested separately according to each histologic type. In serous ovarian carcinoma, high expression of p16, p53, and p27 and low expression of p21 and cyclin E were shown. In addition, this review focuses on the prognostic significance of cell cycle-regulating proteins in EOC. However, it is difficult to compare the results from different groups due to diverse methodologies and interpretations. Accordingly, researchers should establish standardized criteria for the interpretation of immunohistochemical results.

Low-molecular weight forms of cyclin E differentiate ovarian carcinoma from cells of mesothelial origin and are associated with poor survival in ovarian carcinoma

BACKGROUND

The authors recently reported on the role of cyclin E in differentiating ovarian/primary peritoneal carcinoma from malignant peritoneal mesothelioma using gene expression arrays. In the current study, they analyzed the expression of low-molecular weight (LMW) forms of cyclin E in ovarian carcinoma, malignant mesothelioma, and benign reactive effusions.

METHODS

Cyclin E protein expression was analyzed in 98 effusions (72 ovarian carcinomas, 14 malignant mesotheliomas, and 12 reactive specimens) using immunoblotting. Sixty-two ovarian carcinoma effusions were studied further for cyclin E expression using immunohistochemistry. The correlations between cyclin E expression in ovarian carcinoma and clinical parameters, including chemotherapy response, were analyzed.

RESULTS

LMW forms of cyclin E were identified in 54 of 72 ovarian carcinoma effusions (75%) compared with 1 of 14 malignant mesothelioma effusions (7%) and 1 of 12 reactive effusions (8%) (P < .001). Their presence in ovarian carcinoma was associated with a higher percentage of cyclin E-positive cells (P = .001) and increased staining intensity (P < .001) using immunohistochemistry. The presence of LMW forms of cyclin E was correlated with shorter overall survival (P = .021) and progression-free survival (P = .020). The presence of a higher percentage of cyclin E-positive cells using immunohistochemistry was correlated with shorter progression-free survival (P = .026). No association with chemotherapy response was observed.

CONCLUSIONS

LMW forms of cyclin E differentiated ovarian carcinoma from benign and malignant mesothelial cells and were associated with increased protein expression using immunohistochemistry. The expression of LMW cyclin E forms was not associated with chemotherapy response, although it may be a marker of aggressive disease in patients with metastatic ovarian carcinoma.

Cyclin E-associated kinase activity predicts response to platinum-based chemotherapy

PURPOSE

The role of cyclin E as a predictive marker of response to chemotherapy remains unknown. We have previously shown that deregulation of cyclin E in an ovarian tumor cell line model enhances cyclin E-associated kinase activity and sensitizes tumor cells to cisplatinum. We hypothesized that cyclin E deregulation would predict for responsiveness to platinum-based regimens in ovarian cancer patients.

EXPERIMENTAL DESIGN

Patients who met the following criteria were retrospectively identified from the institutional tumor bank records: (a) high-grade ovarian epithelial malignancy, (b) stage III/stage IV disease, (c) optimally debulked, (d) completed platinum-based therapy. Tumor samples were analyzed for cyclin E, p21, and p27 by Western blot analysis and assessed for cyclin E-associated kinase activity.

RESULTS

Seventy-five patients, who met the study criteria, were identified. Cyclin E protein levels did not correlate with cyclin E-cdk2 kinase activity (Spearman's rho, 0.07; P = 0.58). Cyclin E-associated kinase activity was the only significant predictive marker for response to platinum-based therapy, with higher response rates seen in patients with higher levels of activity (P = 0.045). Cyclin E protein levels did not predict for platinum sensitivity (P = 0.20). In contrast, cyclin E protein levels, but not cyclin E-associated kinase activity, was a significant predictor for freedom from recurrence (P = 0.01 and P = 0.25, respectively).

CONCLUSIONS

Cyclin E overexpression and cyclin E-associated kinase activity have distinct roles in predicting for response to chemotherapy and outcome in ovarian cancer patients. These results suggest a compartmentalization of cyclin E functions in the oncogenic process.

CCND1 amplification and cyclin D1 expression in breast cancer and their relation with proteomic subgroups and patient outcome

INTRODUCTION

Despite strong evidence regarding the role of CCND1 amplification and protein overexpression in breast carcinoma, the associations between CCND1 amplification/cyclin D1 overexpression and clinicopathological variables and clinical outcome remain controversial.

AIMS OF THE STUDY

(1) to correlate cyclin D1 expression with gene amplification; (2) to analyse the correlations between CCND1 amplification and overexpression with clinicopathological features and patients' outcome in invasive breast cancer; (3) to define the prevalence and clinical significance of cyclin D1 overexpression and CCND1 amplification in ER positive breast carcinomas (4) to define the prevalence of cyclin D1 overexpression and CCND1 amplification in breast cancers with basal-like immunophenotype.

MATERIALS AND METHODS

CCND1 amplification and protein expression were assessed on a tissue microarray containing 880 unselected invasive breast cancer cases, by means of chromogenic in situ hybridisation using the Spotlight CCND1 amplification probe and immunohistochemistry, using the rabbit monoclonal antibody SP4.

RESULTS

A total of 59/613 tumours (9.6%) showed CCND1 amplification and 224/514 (43.6%) showed strong cyclin D1 expression. A strong positive correlation between CCND1 amplification and higher levels of cyclin D1 expression was found (P < 0.001). Basal-like cancers showed infrequent CCND1 amplification and cyclin D1 overexpression (P < 0.001). Both CCND1 amplification and cyclin D1 expression were associated with positive ER status. CCND1 gene amplification was an independent prognostic factor for patients with ER positive breast cancer.

CONCLUSION

Our results demonstrate a strong correlation between CCND1 amplification and its protein expression in breast cancer. However, protein expression is more pervasive than gene amplification and associated with ER expression.

Estrogen receptor alpha (ESR1) gene amplification is frequent in breast cancer

Using an Affymetrix 10K SNP array to screen for gene copy number changes in breast cancer, we detected a single-gene amplification of the ESR1 gene, which encodes estrogen receptor alpha, at 6q25. A subsequent tissue microarray analysis of more than 2,000 clinical breast cancer samples showed ESR1 amplification in 20.6% of breast cancers. Ninety-nine percent of tumors with ESR1 amplification showed estrogen receptor protein overexpression, compared with 66.6% cancers without ESR1 amplification (P < 0.0001). In 175 women who had received adjuvant tamoxifen monotherapy, survival was significantly longer for women with cancer with ESR1 amplification than for women with estrogen receptor-expressing cancers without ESR1 amplification (P = 0.023). Notably, we also found ESR1 amplification in benign and precancerous breast diseases, suggesting that ESR1 amplification may be a common mechanism in proliferative breast disease and a very early genetic alteration in a large subset of breast cancers.