Expression of cell cycle regulators p57(KIP2), cyclin D1, and cyclin E in epithelial ovarian tumors and survival

Regulatory miRNAs, circRNAs and lncRNAs in cell cycle progression of breast cancer

Breast cancer is a complex and heterogeneous disease that poses a significant public health concern worldwide, and it remains a major challenge despite advances in treatment options. One of the main properties of cancer cells is the increased proliferative activity that has lost regulation. Dysregulation of various positive and negative modulators in the cell cycle has been identified as one of the driving factors of breast cancer. In recent years, non-coding RNAs have garnered much attention in the regulation of cell cycle progression, with microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs) being of particular interest. MiRNAs are a class of highly conserved and regulatory small non-coding RNAs that play a crucial role in the modulation of various cellular and biological processes, including cell cycle regulation. CircRNAs are a novel form of non-coding RNAs that are highly stable and capable of modulating gene expression at posttranscriptional and transcriptional levels. LncRNAs have also attracted considerable attention because of their prominent roles in tumor development, including cell cycle progression. Emerging evidence suggests that miRNAs, circRNAs and lncRNAs play important roles in the regulation of cell cycle progression in breast cancer. Herein, we summarized the latest related literatures in breast cancer that emphasize the regulatory roles of miRNAs, circRNAs and lncRNAs in cell cycle progress of breast cancer. Further understanding of the precise roles and mechanisms of non-coding RNAs in breast cancer cell cycle regulation could lead to the development of new diagnostic and therapeutic strategies for breast cancer.

Analysis of the Whole-Genome Sequences from an Equus Parent-Offspring Trio Provides Insight into the Genomic Incompatibilities in the Hybrid Mule

Interspecific hybridization often shows negative effects on hybrids. However, only a few multicellular species, limited to a handful of plants and animals, have shown partial genetic mechanisms by which hybridization leads to low fitness in hybrids. Here, to explore the outcome of combining the two genomes of a horse and donkey, we analyzed the whole-genome sequences from an Equus parent-offspring trio using Illumina platforms. We generated 41.39× and 46.21× coverage sequences for the horse and mule, respectively. For the donkey, a 40.38× coverage sequence was generated and stored in our laboratory. Approximately 24.86 million alleles were discovered that varied from the reference genome. Single nucleotide polymorphisms were used as polymorphic markers for assigning alleles to their parental genomic inheritance. We identified 25,703 Mendelian inheritance error single nucleotide polymorphisms in the mule genome that were not inherited from the parents through Mendelian inheritance. A total of 555 de novo single nucleotide polymorphisms were also identified. The rate of de novo single nucleotide polymorphisms was 2.21 × 10^-7 in the mule from the Equus parent-offspring trio. This rate is obviously higher than the natural mutation rate for Equus, which is also consistent with the previous hypothesis that interracial crosses may have a high mutation rate. The genes associated with these single nucleotide polymorphisms are mainly involved in immune processes, DNA repair, and cancer processes. The results of the analysis of three genomes from an Equus parent-offspring trio improved our knowledge of the consequences of the integration of parental genomes in mules.

Immunohistochemical Expression of p27Kip1, p57Kip2, Cyclin D1, Nestin, and Ki-67 in Ependymoma

p27 and p57 are tumor suppressors that are dysregulated in many cancers. We investigated the immunohistochemical expression of p27 and p57 in ependymoma, with a secondary emphasis on cyclin D1, nestin, and Ki-67. Sixty-five patients diagnosed with ependymoma were included. Clinical and tumoral data were retrieved, and the expression of p27, p57, cyclin D1, nestin, and Ki-67 was measured. Pearson’s χ2 test was used to measure associations and the Kaplan–Meier method was used for survival analysis. p27 underexpression was significantly associated with pseudopalisading necrosis in tumors with foci of necrosis (p = 0.004). Cyclin D1 overexpression was associated with intracranial (p = 0.044), recurrent (p = 0.022) and grade 3 tumors (p = 0.016); nestin overexpression was associated with supratentorial (p = 0.025), mitotically active (p < 0.001), and grade 3 tumors (p = 0.004); Ki-67 overexpression was associated with supratentorial (p = 0.044) and grade 3 tumors (p < 0.001) and the 3 main features of anaplasia. None of the markers were intercorrelated or predictive of overall survival. In conclusion, p27 underexpression in tumors with foci of necrosis signals a pseudopalisading pattern. Cyclin D1, nestin, and Ki-67 are useful markers in ependymoma, but evidence-based cutoff values are required to standardize this interpretation.

Lidocaine inhibits the proliferation of lung cancer by regulating the expression of GOLT1A

OBJECTIVES

Lidocaine is the most commonly used local anaesthetic in clinical and can inhibit proliferation, suppress invasion and migration and induce apoptosis in human lung adenocarcinoma (LAD) cells. However, its specific downstream molecular mechanism is unclear.

MATERIALS AND METHODS

LAD cell lines, A549 and H1299 cells, were treated with lidocaine. The proliferation was evaluated by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) and bromodeoxyuridine (BrdU) assay. The expression level of related proteins was detected by real-time quantitative PCR (qPCR) and Western blot assay.

RESULTS

The results indicated that lidocaine dose-dependently suppressed the proliferation of A549 and H1299 cells. In the LAD patients' samples, GOLT1A was upregulated and involved in the poor prognosis and higher grade malignancy. Additionally, GOLT1A mediates the function of lidocaine on repressing proliferation by regulating the cell cycle in A549 cells.

CONCLUSIONS

Our findings suggest that lidocaine downregulates the GOLT1A expression to repress the proliferation of lung cancer cells.

miR-497 expression, function and clinical application in cancer

MicroRNAs (miRNAs) are small non-coding RNAs that inhibit gene expression by binding to the 3' untranslated region (3'-UTR) of their target mRNAs. Recent studies show that miR-497 plays an important role in various cancers. Here, we summarize the existing studies of miR-497 as following: (1) miR-497 expression in cancer; (2) regulation mechanisms of miR-497 expression; (3) function of miR-497 in cancer; (4) direct targets of miR-497; (5) Clinical applications of miR-497. Recent analyses verify that miR-497 mainly suppresses tumors; however, it also acts as an oncogene in several cancers. Increasing evidence indicates that miR-497 can serve as a diagnostic and prognostic biomarker and is a promising therapeutic target for future clinical applications.

Cyclin-dependent kinase 2 is an ideal target for ovary tumors with elevated cyclin E1 expression

CCNE1 gene amplification is present in 15-20% ovary tumor specimens. Here, we showed that Cyclin E1 (CCNE1) was overexpressed in 30% of established ovarian cancer cell lines. We also showed that CCNE1 was stained positive in over 40% of primary ovary tumor specimens regardless of their histological types while CCNE1 staining was either negative or low in normal ovary and benign ovary tumor tissues. However, the status of CCNE1 overexpression was not associated with the tumorigenic potential of ovarian cancer cell lines and also did not correlate with pathological grades of ovary tumor specimens. Subsequent experiments with CCNE1 siRNAs showed that knockdown of CCNE1 reduced cell growth only in cells with inherent CCNE1 overexpression, indicating that these cells may have developed an addiction to CCNE1 for growth/survival. As CCNE1 is a regulatory factor of cyclin-dependent kinase 2 (Cdk2), we investigated the effect of Cdk2 inhibitor on ovary tumorigenecity. Ovarian cancer cells with elevated CCNE1 expression were 40 times more sensitive to Cdk2 inhibitorSNS-032 than those without inherent CCNE1 overexpression. Moreover, SNS-032 greatly prolonged the survival of mice bearing ovary tumors with inherent CCNE1 overexpression. This study suggests that ovary tumors with elevated CCNE1 expression may be staged for Cdk2-targeted therapy.

High Skp2/Low p57(Kip2) Expression is Associated with Poor Prognosis in Human Breast Carcinoma

Downregulation of p57^Kip2 is involved in tumor progression, and S-phase kinase-associated protein 2 (Skp2) is an E3 ligase that regulates a variety of cell cycle proteins. However, the prognostic value of p57^Kip2 and its correlation with Skp2 in breast cancer have not been fully elucidated. Here we report our study on the expression of p57^Kip2 and Skp2 in 102 breast cancer patients by immunohistochemistry, and analysis of clinicopathologic parameters in relation to patient prognosis. The expression of p57^Kip2 was negatively associated with Skp2 expression in breast cancer (r = −0.26, P = 0.009). Kaplan–Meier analysis indicated that both high Skp2 and low p57^Kip2 correlated with poor disease-free survival (DFS) (P = 0.05), and a group with the combination of high Skp2/low p57^Kip2 demonstrated even worse DFS (log-rank = 21.118, P < 0.001). In addition, univariate analysis showed that Skp2, p57^Kip2, histological grade, lymph node metastasis, and estrogen and progesterone receptors (ER and PR) were all associated with DFS, and multivariate analysis revealed that lymph node metastasis and Skp2 were independent prognostic biomarkers. The correlation between p57 and Skp2 was further demonstrated in multiple breast cancer cell lines and cell cycle phases. Half-life and immunoprecipitation (IP) experiments indicated that Skp2 directly interacts with p57^Kip2 and promotes its degradation, rather than its mutant p57^Kip2 (T310A). Overall, our findings demonstrate that Skp2 directly degrades p57^Kip2, and an inverse correlation between these proteins (high skp2/low p57^Kip2) is associated with poor prognosis in breast cancer. Thus, our results indicate a combined prognostic value of these markers in breast cancer diagnosis and treatment.

Long noncoding RNAs(lncRNAs) and the molecular hallmarks of aging

During aging, progressive deleterious changes increase the risk of disease and death. Prominent molecular hallmarks of aging are genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, cellular senescence, stem cell exhaustion, and altered intercellular communication. Long noncoding RNAs (lncRNAs) play important roles in a wide range of biological processes, including age-related diseases like cancer, cardiovascular pathologies, and neurodegenerative disorders. Evidence is emerging that lncRNAs influence the molecular processes that underlie age-associated phenotypes. Here, we review our current understanding of lncRNAs that control the development of aging traits.

MicroRNA-30c-2-3p negatively regulates NF-κB signaling and cell cycle progression through downregulation of TRADD and CCNE1 in breast cancer

Nuclear Factor kappa B (NF-κB) signaling is frequently deregulated in a variety of cancers and is constitutively active in estrogen receptor negative (ER-) breast cancer subtypes. These molecular subtypes of breast cancer are associated with poor overall survival. We focused on mechanisms of NF-κB regulation by microRNAs (miRNAs), which regulate eukaryotic gene expression at the post-transcriptional level. In a previous genome-wide miRNA screen, we had identified miR-30c-2-3p as one of the strongest negative regulators of NF-κB signaling. Here we have uncovered the underlying molecular mechanisms and its consequences in breast cancer. In vitro results show that miR-30c-2-3p directly targets both TNFRSF1A-associated via death domain (TRADD), an adaptor protein of the TNFR/NF-κB signaling pathway, and the cell cycle protein Cyclin E1 (CCNE1). Ectopic expression of miR-30c-2-3p downregulated essential cytokines IL8, IL6, CXCL1, and reduced cell proliferation as well as invasion in MDA-MB-231 breast cancer cells. RNA interference (RNAi) induced silencing of TRADD phenocopied the effects on invasion and cytokine expression caused by miR-30c-2-3p, while inhibition of CCNE1 phenocopied the effects on cell proliferation. We further confirmed the tumor suppressive role of this miRNA using a dataset of 781 breast tumors, where higher expression was associated with better survival in breast cancer patients. In summary we have elucidated the mechanism by which miR-30c-2-3p negatively regulates NF-κB signaling and cell cycle progression in breast cancer.

MiRNA-497 regulates cell growth and invasion by targeting cyclin E1 in breast cancer

Background

MicroRNAs are a class of endogenous single strand non-coding RNAs that are involved in many important physiological and pathological processes. The purpose of this study was to examine the expression levels of miR-497 in human breast cancer and its function in MDA-MB-231 breast cancer cells.

Methods

Quantitative polymerase chain reaction was used to measure the expression levels of miR-497 in 40 breast cancer specimens and adjacent normal breast tissues. MTT assays, colony formation assays, wound healing assays, transwell assays and cell cycle assays were used to explore the potential function of miR-497 in MDA-MB-231 breast cancer cells. Dual-luciferase reporter assays were performed to analyze the regulation of putative target of miR-497, and western blot assays were used to validate the dual-luciferase results.

Results

The expression of miR-497 in breast cancer specimens was lower than adjacent normal tissues (P < 0.05). Overexpression of miR-497 inhibited cellular growth, suppressed cellular migration and invasion, and caused a G1 arrest. Dual-luciferase reporter assays showed that miR-497 binds the 3′-untranslated region (3′-UTR) of cyclin E1, suggesting that cyclin E1 is a direct target of miR-497. Western blot assays confirmed that overexpression of miR-497 reduced cyclin E1 protein levels.

Conclusions

MiR-497 may act as a tumor suppressor gene in breast cancer. Inhibited cellular growth, suppressed cellular migration and invasion, and G1 cell cycle arrest were observed upon overexpression of miR-497 in cells, possibly by targeting cyclin E1. These results indicate miR-497 could be considered a therapeutic target for the development of treatment for breast cancer.

Expression of p15INK⁴b and p57KIP² and relationship with clinicopathological features and prognosis in patients with vulvar squamous cell carcinoma

Background

The cyclin-dependent kinase inhibitors p15^INK4b and p57^KIP2 are important regulators of the cell cycle, and their abnormal expression has been detected in various tumors. However, little is known about the role of p15^INK4b and p57^KIP2 in the pathogenesis of vulvar carcinoma, and the prognostic impact is still unknown. In our current study, we examined the expression of p15^INK4b and p57^KIP2 in a large series of vulvar squamous cell carcinomas to elucidate the prognostic impact.

Methods

Expression of p15^INK4b and p57^KIP2 were examined in 297 vulvar squamous cell carcinomas using immunohistochemistry. Both uni- and multivariate analysis of prognostic factors were performed, and correlations with clinicopathologic parameters were examined.

Results

Compared to the high levels of p15^INK4b and p57^KIP2 in normal vulvar squamous epithelium, low levels of p15^INK4b and p57^KIP2 were found in 82% and 44% of vulvar carcinomas, respectively. Low levels of p15^INK4b and p57^KIP2 correlated significantly with malignant features, including large tumor diameter (p = 0.03 and p = 0.001, respectively) and increased invasiveness (p = 0.003 and p = 0.04, respectively). Although p15^INK4b and p57^KIP2 levels could not be identified as prognostic markers, combined analysis of p14^ARF/p15^INK4b/p16^INK4a showed that patients whose tumors expressed low levels of two or three of these INK4 proteins had a worse prognosis than those with only low levels of one or no protein (univariate analysis p = 0.02). The independent prognostic significance of these INK4 proteins was confirmed by multivariate analysis (p = 0.008).

Conclusions

We show for the first time that p15^INK4b and p57^KIP2 may be involved in the progression of vulvar carcinomas and the combined p14^ARF/p15^INK4b/p16^INK4a status was a statistically independent prognostic factor.

Relevance of immunohistochemical expression of p57kip2 in epithelial ovarian carcinoma- A systematic literature review

Background

Epithelial Ovarian Cancer (EOC) is the second most common gynaecological cancer and accounts for more deaths than all gynaecological cancers combined. Despite extensive research, progress has been slow in understanding the pathobiology. EOC is identified as a heterogeneous malignancy with various histological subtypes. It is now well known that these different histological subtypes show differences in terms of presentation, response to treatment, immunohistochemical (IHC) reactivity and molecular profiling. Cell cycle deregulation is key in cancer development and there is some evidence in the literature that this is relevant to the problem of EOC and the development of drug resistant disease. The need to identify prognostic markers has led to several gene profiling studies using tumour tissue with equivocal results. p57^kip2 is one such cell cycle regulator and its functions are being explored as recent research has shown that it is more than just a negative regulator of the cell cycle.

Aims

The aim of this review is to evaluate the literature around the IHC expression of p57^kip2 in EOC.

Methods

Systematic review of the literature focussing on clinical outcome and immunohistochemical expression in epithelial ovarian cancer.

Results

Four papers are discussed in this review and have shown great variation in IHC expression of p57^kip2 in EOC. These studies incorporated different histological subtypes of EOC. However they all suggest that p57^kip2 has a significant role in prognosis and its therapeutic indication needs to be studied. Multicentre collaborative studies on individual histological subtypes might provide more data and help to increase the number of cases especially for rarer tumours.

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.

The cyclin-dependent kinase inhibitor p57(Kip2) is epigenetically regulated in carboplatin resistance and results in collateral sensitivity to the CDK inhibitor seliciclib in ovarian cancer

Background:

Carboplatin remains a first-line agent in the management of epithelial ovarian cancer (EOC). Unfortunately, platinum-resistant disease ultimately occurs in most patients. Using a novel EOC cell line with acquired resistance to carboplatin: PEO1CarbR, genome-wide micro-array profiling identified the cyclin-dependent kinase inhibitor p57^Kip2 as specifically downregulated in carboplatin resistance. Presently, we describe confirmation of these preliminary data with a variety of approaches.

Methods:

Cytotoxicity testing (MTT) and cell cycle blockade assessed drug responsiveness. Methylation specific PCR and pyrosequencing identified sites of promoter methylation in p57^Kip2. siRNA to p57^Kip2 was used to look at the changes in apoptosis of carboplatin treated EOC cells. EOC tissues (20 cases) were assessed for mRNA levels of p57^Kip2.

Results:

Carboplatin resistance was reversed using 5-aza-cytidine in vitro. Promoter methylation sites and preferential sensitivity to seliciclib were seen in PEO1CarbR cells. Silencing p57^Kip2 decreased the apoptotic response to the effects of platinum but produced sensitisation to seliciclib. EOC biopsies indicated an association of high levels of p57^Kip2mRNA with complete responses to chemotherapy and improved outcome.

Conclusion:

We conclude that p57^Kip2 is a candidate biomarker of platinum sensitivity/resistance in EOC and such cases may show preferential response to the cyclin-dependent kinase inhibitor seliciclib.

Nuclear P27 expression in benign, borderline (LMP) and invasive tumors of the ovary and its association with prognosis: a gynecologic oncology group study

OBJECTIVE

Nuclear p27 expression was examined in non-invasive and invasive ovarian tumors from a cross-sectional study, and clinical relevance of p27 was evaluated in the primary tumors from women participating in two randomized phase III treatment trials.

METHODS

An immunohistochemistry assay was used to detect p27 in formalin-fixed paraffin-embedded ovarian tumors from 3 distinct sources.

RESULTS

Among the initial 91 ovarian tumors tested, low p27 expression (<50% positive cells) was observed in 5.4% of non-invasive tumors versus 42.6% of invasive tumors (p<0.001). In 145 ovarian cancers with high-risk early stage disease, 16.5% exhibited low p27 expression, and categorized p27 was not associated with age, race, or performance status. Low expression of p27 was common in poorly differentiated tumors (35.7%) compared to moderately (15.0%) and well (9.5%) differentiated tumors (p=0.024) and rare in clear cell carcinomas (2.4%) compared to other histologies (p=0.014). In the 139 cancers with advanced disease, 60% displayed low p27 expression, and categorized p27 expression was not associated with age, race, performance status, tumor grade, histologic subtype, measurable disease status or survival. Exploratory analyses revealed an association of cyclin E to p27 ratio >1.0 with an increased risk of death (hazard ratio=1.53; p=0.017).

CONCLUSIONS

Low p27 expression could be associated with malignant transformation of the ovarian epithelium and FIGO stage. A cyclin E to p27 ratio >1.0 may be associated with shorter survival in these patients. Further study is required to confirm the trend for increased recurrences with low p27 expression in early stage disease.

MiR-221 and MiR-222 alterations in sporadic ovarian carcinoma: Relationship to CDKN1B, CDKNIC and overall survival

MicroRNAs are often aberrantly expressed in human neoplasms and are postulated to play a role in neoplastic initiation and progression. miR-221 and miR-222 negatively regulate expression of CDKN1B (p27) and CDKN1C (p57), two cell cycle regulators expressed in ovarian surface epithelium and down-regulated in ovarian carcinomas. We characterized miR-221 and miR-222 expression in 49 sporadic high grade ovarian carcinomas and determined whether somatic mutation or epigenetic alterations explained the differences in expression of these miRNAs. We correlated these findings with protein expression of CDKN1B and CDKN1C as assessed by immunohistochemistry. Expression of miR-221 and miR-222 were closely correlated with each other (P = 0.0001). Interestingly, a lower ratio of miR-221 to miR-222 expression was significantly correlated with worse overall survival (P = 0.01) and remained a significant predictor of overall survival in multivariate analysis using the covariate adequacy of surgical cytoreduction (P = 0.03). Higher miR-222 and miR-221 expression were significantly associated with decreased CDKN1C expression (P = 0.009 and 0.01). In contrast, CDKN1B expression was not associated with miR-221 or miR-222 expression. Neither somatic mutations nor methylation of the studied region explained the alterations in miR-221 and miR-222 expression in most carcinomas.

Predictive and prognostic protein biomarkers in epithelial ovarian cancer: recommendation for future studies

Epithelial ovarian cancer is the most lethal gynecological malignancy. Due to its lack of symptoms, this disease is diagnosed at an advanced stage when the cancer has already spread to secondary sites. While initial rates of response to first treatment is >80%, the overall survival rate of patients is extremely low, mainly due to development of drug resistance. To date, there are no reliable clinical factors that can properly stratify patients for suitable chemotherapy strategies. Clinical parameters such as disease stage, tumor grade and residual disease, although helpful in the management of patients after their initial surgery to establish the first line of treatment, are not efficient enough. Accordingly, reliable markers that are independent and complementary to clinical parameters are needed for a better management of these patients. For several years, efforts to identify prognostic factors have focused on molecular markers, with a large number having been investigated. This review aims to present a summary of the recent advances in the identification of molecular biomarkers in ovarian cancer patient tissues, as well as an overview of the need and importance of molecular markers for personalized medicine in ovarian cancer.

p57KIP2: "Kip"ing the cell under control

p57(KIP2) is an imprinted gene located at the chromosomal locus 11p15.5. It is a cyclin-dependent kinase inhibitor belonging to the CIP/KIP family, which includes additionally p21(CIP1/WAF1) and p27(KIP1). It is the least studied CIP/KIP member and has a unique role in embryogenesis. p57(KIP2) regulates the cell cycle, although novel functions have been attributed to this protein including cytoskeletal organization. Molecular analysis of animal models and patients with Beckwith-Wiedemann Syndrome have shown its nodal implication in the pathogenesis of this syndrome. p57(KIP2) is frequently down-regulated in many common human malignancies through several mechanisms, denoting its anti-oncogenic function. This review is a thorough analysis of data available on p57(KIP2), in relation to p21(CIP1/WAF1) and p27(KIP1), on gene and protein structure, its transcriptional and translational regulation, and its role in human physiology and pathology, focusing on cancer development.

Overexpression of delta Np63 in a human nasopharyngeal carcinoma cell line downregulates CKIs and enhances cell proliferation

p63 belongs to a member of the tumor suppressor protein p53 family. Due to alternative promoter usage, two types of p63 proteins are produced. The DeltaNp63 isoform lacks the N-terminal transactivation domain and is thought to antagonize TAp63 and p53 in target gene regulation. DeltaNp63 has been found to be overexpressed in numerous human squamous cell carcinomas, including nasopharyngeal carcinoma (NPC). However, the role of DeltaNp63 overexpression in NPC pathogenesis has not been clear. In this study, we use a DeltaNp63 overexpressing human NPC cell line (NPC-076) to explore the possible roles of DeltaNp63 in cell proliferation and cell-cycle regulation. We found that the proliferation of NPC-076 cell is greatly suppressed when the overexpressed DeltaNp63 is silenced by specific DeltaNp63 siRNA. Further studies show that DeltaNp63 silencing results in the upregulation of CKIs, including p27(kip1) and p57(kip2) in both mRNA and protein levels. Cell-cycle analysis shows that DeltaNp63 silencing also results in an increased G1 phase cell and apoptotic cell population. Our findings indicate that DeltaNp63 plays important roles in the regulation of NPC-076 cell-cycle progression, and may play a role in the maintenance of NPC-076 tumor cell phenotype.

Analysis of gene expression in early-stage ovarian cancer

PURPOSE

Gene expression profile was analyzed in 68 stage I and 15 borderline ovarian cancers to determine if different clinical features of stage I ovarian cancer such as histotype, grade, and survival are related to differential gene expression.

EXPERIMENTAL DESIGN

Tumors were obtained directly at surgery and immediately frozen in liquid nitrogen until analysis. Glass arrays containing 16,000 genes were used in a dual-color assay labeling protocol.

RESULTS

Unsupervised analysis identified eight major patient partitions, one of which was statistically associated to overall survival, grading, and histotype and another with grading and histotype. Supervised analysis allowed detection of gene profiles clearly associated to histotype or to degree of differentiation. No difference was found between borderline and grade 1 tumors. As to recurrence, a subset of genes able to differentiate relapsers from nonrelapsers was identified. Among these, cyclin E and minichromosome maintenance protein 5 were found particularly relevant, as their expression was inversely correlated to progression-free survival (P = 0.00033 and 0.017, respectively).

CONCLUSIONS

Specific molecular signatures define different histotypes and prognosis of stage I ovarian cancer. Mucinous and clear cells histotypes can be distinguished from the others regardless of tumor grade. Cyclin E and minichromosome maintenance protein 5, whose expression was found previously to be related to a bad prognosis of advanced ovarian cancer, appear to be potential prognostic markers in stage I ovarian cancer too, independent of other pathologic and clinical variables.

Cyclin E overexpression in epithelial ovarian cancer characterizes an etiologic subgroup

BACKGROUND

The objective of this study was to determine whether cyclin E overexpression defines an etiologically distinct subgroup of ovarian cancer.

METHODS

We analyzed data from 538 epithelial ovarian cancer cases and 629 controls enrolled in a population-based case-control study. Cyclin E protein overexpression was assessed using immunohistochemistry. Case-control and case-case comparisons were done to evaluate the relationship between cyclin E overexpression and epidemiologic risk factors. Logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) while adjusting for potential confounders.

RESULTS

Case-control comparisons showed ovarian cancers with and without cyclin E overexpression have different associations with several epidemiologic risk factors. A dose-response relationship was observed between lifetime ovulatory cycles (LOC) and ovarian cancer that overexpressed cyclin E [OR, 1.8; 95% CI, 1.1-3.0 for moderately high LOC (265-390 cycles) and OR, 2.7; 95% CI, 1.6-4.5 for high LOC (>390 cycles) compared with low LOC (<265 cycles)], but no relationship was seen with cancers that lacked overexpression. The most important components of the LOC variable contributing to the differences in the association with the cyclin E subgroups of ovarian cancer were months of oral contraceptive use and months pregnant.

CONCLUSIONS

Cyclin E overexpression is associated with a high number of LOC, largely influenced by oral contraceptive use and pregnancy. This suggests that cyclin E overexpression is a molecular signature characteristic of ovarian cancer cases that may arise via a pathway that involves ovulation-induced alterations.

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.

The clinical importance of Ki-67, p16, p14, and p57 expression in patients with advanced ovarian carcinoma

The present study addressed the impact of p14, p16, p57, and Ki-67 in a large cohort of uniformly treated patients with stage III ovarian cancer in relation to other clinicopathologic variables and prognosis. We immunohistochemically studied 171 primary tumors from previously untreated patients with advanced ovarian carcinomas for expression of Ki-67, p16, p14, and p57. High protein levels of Ki-67 (>10% positive nuclei) were found in 144 cases (84%), p16 (>50% positive nuclei) in 53 cases (31%), p57 (>10% positive nuclei) in 41 cases (24%), and p14 (any positive nuclei) in 19 cases (11%). A correlation between high Ki-67 expression and presence of residual disease after primary surgery (P = 0.019), ascites (P = 0.006), higher International Federation of Gynecology and Obstetrics substage (P < 0.001), poor differentiation (P < 0.001), and higher Silverberg histopathologic grade (P < 0.0001) was seen. High expression of p16 correlated to poor differentiation (P = 0.033) and higher Silverberg histopathologic grade (P = 0.018). In univariate analysis, high expression of Ki-67 (P = 0.0001) and p16 (P = 0.005) was associated with poor survival. However, in multivariate analysis, only high expression of Ki-67 was significantly associated with shorter survival (P = 0.025). No correlations were seen between expression of p14 and p57 and clinicopathologic parameters. None of the factors studied was able to predict response to chemotherapy. Our results showed that Ki-67 represents an independent prognostic predictor in stage III ovarian cancer. We did not find p16, p14, and p57 to be useful as prognostic markers.

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.

Significance of E2F-1 overexpression in epithelial ovarian cancer

E2F-1 is a downstream regulator of the Rb pathway and is a transcription factor that plays a key role in the control of cell cycle progression. Deregulation of E2F-1 expression and Rb pathway is involved in carcinogenesis. The aim of this study was to evaluate E2F-1 expression and Rb pathway alteration and to elucidate their correlation with clinical and pathologic parameters in epithelial ovarian cancer (EOC). We investigated overexpression of E2F-1 and alterations of p16(INK4a), cyclin D1, CDK4, and pRb using immunohistochemistry and tissue microarray methods in 72 EOC patients. Overexpression of E2F-1 was detected in 45.8% of samples. The overall abnormal expression frequencies of p16(INK4a), cyclin D1, CDK4, and pRb were 33.3%, 11.1%, 12.5%, and 38.9%, respectively. E2F-1 overexpression was not associated with alteration of the Rb pathway. E2F-1 overexpression was correlated with FIGO stage, histologic grade, and mitotic index; it was a valuable prognostic variable along with FIGO stage in the multivariated analysis. The results suggest that E2F-1 has a growth-promoting effect in EOC and that E2F-1 overexpression may provide a useful prognostic indicator for EOC.

Expression of human telomerase reverse transcriptase and cyclin-D1 in olfactory neuroblastoma

Olfactory neuroblastoma is an uncommon neoplasm. Typically, these tumors are indolent with long-standing symptomatology, but the fact that the lesions are indeed malignant has been proven by the repeated demonstration that they can metastasize to distant organs. Suitable prognostic factors are lacking and therapeutic strategy still remains controversial. Expression of human telomerase reverse transcriptase (hTERT) is associated with most human malignancies and high levels have been correlated with poor prognosis in many cancers. In comparison, overexpression of cyclin-D1 occurs in several malignancies and has been associated with aggressive tumor behavior and poorer prognosis. In this study, we collected 16 olfactory neuroblastomas from the Kaohsiung Medical University Hospital. The aim was to investigate the value of immunoexpression of hTERT and cyclin-D1 in correlation with clinicopathologic features of olfactory neuroblastoma. Low and high cyclin-D1 expression was found in 6 and 10 cases, respectively. For hTERT, low and high protein expression was detected in 5 and 11 tumors, respectively. Cyclin-D1 expression was not correlated with selected parameters. However, high hTERT expression was significantly correlated with high Kadish stage. In conclusion, high hTERT expression can be considered a potential indicator of aggressive olfactory neuroblastoma.

Expression of the chromatin remodeling factor Rsf-1 is upregulated in ovarian carcinoma effusions and predicts poor survival

OBJECTIVE

We recently identified Rsf-1, a chromatin remodeling gene, as a potential oncogene that is frequently amplified and overexpressed in ovarian serous carcinoma. However, its clinical role in ovarian cancer effusions is not clear. In the present study, we assessed the clinical significance of Rsf-1 overexpression in ovarian carcinoma effusions.

METHODS

Formalin-fixed paraffin-embedded sections from 168 effusions (134 peritoneal, 34 pleural) were analyzed for Rsf-1 expression using immunocytochemistry. Matched primary tumors (n=48) and solid metastases (n=73) from 48 patients were additionally studied. Rsf-1 expression in tumor cells in effusions was analyzed for possible association with clinicopathologic parameters and survival.

RESULTS

Rsf-1 protein expression was found in carcinoma cells in 157/168 (93%) effusions. Of these, 70 (45%) stained weakly and 87 (55%) strongly. Specimens from patients diagnosed with FIGO stage IV disease had higher staining score (extent x intensity) compared with stage III tumors (P=0.008). Rsf-1 expression level was significantly lower in primary tumors and solid metastases (P<0.001 for extent, intensity and score). Univariate survival analysis for 59 patients with post-chemotherapy recurrence effusions demonstrated a significant association between higher Rsf-1 staining and shorter overall survival (OS; P=0.009 for staining extent and intensity, P=0.02 for staining score). FIGO stage was the only clinical parameter associated with OS in this group (P=0.032). In Cox analysis, Rsf-1 expression (P=0.022 for staining extent and intensity, P=0.045 for staining score) and FIGO stage (P=0.035) were independent predictors of shorter survival.

CONCLUSIONS

Rsf-1 is frequently expressed and upregulated in ovarian carcinoma cells in effusions and is a novel prognostic marker for patients with post-chemotherapy recurrent disease. The above findings support a role of Rsf-1 in mediating disease progression and aggressive clinical behavior in this subset of ovarian carcinoma patients.

Tissue array analysis of expression microarray candidates identifies markers associated with tumor grade and outcome in serous epithelial ovarian cancer

Molecular profiling is a powerful approach to identify potential clinical markers for diagnosis and prognosis as well as providing a better understanding of the biology of epithelial ovarian cancer. On the basis of the analysis of HuFL expression data, we have previously identified genes that distinguish low malignant potential and invasive serous epithelial ovarian tumors. In this study, we used immunohistochemistry to monitor a subset of differently expressed candidates (Ahr, Paep, Madh3, Ran, Met, Mek1, Ccne1, Ccd20, Cks1 and Cas). A tissue array composed of 244 serous tumors of different grades (0-3) and stages (I-IV) was used in this analysis. All markers assayed presented differential protein expression between serous tumors of low and high grade. Significant differences in Ccne1 and Ran expression were observed in a comparison of low malignant potential and grade 1 tumor samples (p<0.01). In addition, irrespective of the grade, Ccne1, Ran, Cdc20 and Cks1 showed significant differences of expression in association with the clinical stage of disease. While high level of Ccne1 have previously been associated with poor outcomes, here we found that high level of either Ran or Cdc20 appear to be more tightly associated with a poor prognosis (p<0.001, 0.03, respectively). The application of these biomarkers in both the initial diagnosis and prognostic attributes of patients with epithelial ovarian tumors should prove to be useful in patient management.

Cyclin E expression is correlated with tumor progression and predicts a poor prognosis in patients with ovarian carcinoma

BACKGROUND

Cyclins, cyclin dependent kinases (cdks), and their inhibitors act in combination to regulate progression through the cell cycle and often are dysregulated in carcinoma. The authors hypothesized that cyclin E plays an important role in ovarian carcinogenesis and that its overexpression may be an indicator of a poor prognosis.

METHODS

Immunohistochemical analysis of cyclin E expression was performed by image analysis in normal ovaries, cystadenomas, tumors of low malignant potential, and 405 primary ovarian carcinomas by using tissue microarray technology.

RESULTS

Overexpression of cyclin E was found in 63.2% of the samples and was associated with clear cell, poorly differentiated, and serous carcinoma (P < or = .001), high-grade tumors (P < or = .001), late-stage disease (P = .002), age older than 60 years at the time of diagnosis (P = .04), and suboptimal cytoreduction (P = .001). A high percentage of cyclin E-expressing cells was associated with a poor outcome in univariate and in multivariate analyses. In addition, cyclin E levels also reduced survival in the late-stage disease group and in patients who underwent suboptimal debulking.

CONCLUSIONS

Cyclin E was identified as an independent prognostic factor in patients with ovarian carcinoma. The accumulation of cyclin E protein may be a late event in tumorigenesis and may contribute to disease progression in these patients.

Cell cycle genes in ovarian cancer: steps toward earlier diagnosis and novel therapies

Human malignant tumors are characterized by abnormal proliferation resulting from alterations in cell cycle-regulatory mechanisms. The regulatory pathways controlling cell cycle phases include several oncogenes and tumor suppressor genes that display a range of abnormalities with potential usefulness as markers of evolution or treatment response in ovarian cancer. This review summarizes the current knowledge about these aberrations in malignant tumors of the ovary. We sought to divide cell cycle-regulatory genes into four subgroups on the basis of their predominant role in a specific phase or during the transition between two phases of the cell cycle.

Expression of cell cycle regulator p57kip2, cyclinE protein and proliferating cell nuclear antigen in human pancreatic cancer: An immunohistochemical study

AIM: To investigate the effects of p57^kip2, cyclinE protein and proliferating cell nuclear antigen (PCNA) on occurrence and progression of human pancreatic cancer.

METHODS: The expression of p57^kip2, cyclinE protein and PCNA in tumor tissues and adjacent tissues from 32 patients with pancreatic cancer was detected by SP immunohistochemical technique.

RESULTS: The positive expression rate of p57^kip2 protein in tumor tissues was 46.9%, which was lower than that in adjacent pancreatic tissues (χ² = 5.317, P<0.05). p57^kip2 protein positive expression remarkably correlated with tumor cell differentiation (P<0.05), but not with lymph node metastasis (P>0.05). The positive expression rate of cyclinE protein in tumor tissues was 68.8%, which was higher than that in adjacent pancreatic tissues (χ² = 4.063, P<0.05). CyclinE protein positive expression significantly correlated with tumor cell differentiation and lymph node metastasis (P<0.05). The positive expression rate of PCNA in the tumor tissues was 71.9%, which was higher than that in adjacent pancreatic tissues (χ² = 5.189, P<0.05). PCNA positive expression remarkably correlated with tumor cell differentiation and lymph node metastasis (P<0.05).

CONCLUSION: The decreased expression of p57^kip2 and/or overexpression of cyclinE protein and PCNA may contribute to the occurrence and progression of pancreatic cancer. p57^kip2, cyclinE protein, and PCNA play an important role in occurrence and progression of pancreatic cancer.

Cyclins D1, D3, E, and A in vulvar carcinoma patients

OBJECTIVE

The treatment of vulvar squamous cell carcinoma patients is often mutilating. Effort is being made to individualize treatment in order to reduce negative side effects for patients with good prognosis. Molecular markers have been able to predict patient outcome in several tumors. The aim of this study was to characterize the expression of cyclins D1, D3, E, and A in a comparatively large series of patients with vulvar squamous cell carcinoma and look for prognostic impact.

METHODS

A total of 224 vulvar squamous cell carcinomas were immunohistochemically investigated for expression of cyclins D1, D3, E, and A using the biotin-streptavidin-peroxidase method and the OptiMax Plus automated cell staining system.

RESULTS

High protein levels of cyclin D1 (any positive nuclei) were found in 58 (26%) cases, cyclin D3 (> or =50% positive nuclei) in 61 (27%) cases, cyclin E (> or =50% positive nuclei) in 41 (18%) cases, and cyclin A (> or =5% positive nuclei) in 156 (70%) cases. No prognostic impact was found for the cyclins D1, D3, E, or A.

CONCLUSIONS

The high number of cases showing increased levels of cyclin A suggests that this protein may be important in the pathogenesis of vulvar squamous cell carcinoma. No prognostic impact was found for the cyclins D1, D3, E, or A.

Discrimination between serous low malignant potential and invasive epithelial ovarian tumors using molecular profiling

Tumors of low malignant potential (LMP) represent 20% of epithelial ovarian cancers (EOCs) and are associated with a better prognosis than the invasive tumors (TOV). Defining the relationship between LMPs and TOVs remains an important goal towards understanding the molecular pathways that contribute to prognosis, as well as providing molecular markers, for these EOCs. To this end, DNA microarray analyses were performed either in a primary culture or a tumor tissue model system and selected candidate genes showing a distinctive expression profile between LMPs and TOVs were identified using a class prediction approach based on three statistical methods of analysis. Both model systems appear relevant as candidate genes identified by either model allowed the proper reclassification of samples as either LMPs or TOVs. Selected candidate genes (CAS, CCNE1, LGALS8, ITGbeta3, ATP1B1, FLIP, KRT7 and KRT19) were validated by real-time quantitative PCR analysis and show differential expression between LMPs and TOVs. Immunohistochemistry analyses showed that the two tumor classes were distinguishable by their expression of CAS, TNFR1A, FLIP, CKS1 and CCNE1. These results define signature patterns for gene expression of LMPs and TOVs and identify gene candidates that warrant further study to deepen our understanding of the biology of EOC.

Distinction between serous tumors of low malignant potential and serous carcinomas based on global mRNA expression profiling

OBJECTIVES

The molecular pathogenesis of ovarian serous tumors of low malignant potential (S-LMP) is not well understood, although the collective data suggest that they arise through molecular mechanisms distinct from those leading to conventional serous carcinomas (S-Ca). To further examine the molecular differences between these two diseases, we studied the gene expression pattern of ovarian S-LMP and S-Ca using high-density spotted cDNA and tissue microarrays.

METHODS

Total RNA from 23 ovarian S-LMP and S-Ca was analyzed on 43,200 spot cDNA microarrays and the differential expression of proteins encoded by differentially expressed genes was validated using tissue microarrays.

RESULTS

Unsupervised hierarchical clustering analysis of filtered data showed a complete separation between S-LMP and S-Ca, based predominantly on a small set of genes expressed at higher levels in S-LMP than in S-Ca. Many genes previously identified as up-regulated in ovarian carcinoma relative to normal ovarian tissue were expressed at even higher levels in S-LMP. These genes included mucin-1, mesothelin, HE4, PAX 8, and apolipoprotein J/clusterin. Immunohistochemical staining of tissue microarrays confirmed higher expression of selected proteins encoded by these genes in the S-LMP. Few genes were expressed at a higher level in S-Ca; these included E2F1, topoisomerase IIalpha, and cyclin E, with higher levels of cyclin E protein confirmed by immunohistochemistry.

CONCLUSIONS

S-LMP and S-Ca are distinguished at the molecular level by a relatively small gene set, suggesting the pathogenesis of S-LMP as well as S-Ca may involve molecular pathways that escape detection by global gene expression profiling. In order to obtain biologically and clinically relevant information about the mechanisms involved in ovarian carcinogenesis, future studies based on molecular profiles of ovarian cancer should include analyses of low malignant potential tumors. Inclusion of such tumors is also critical to the evaluation of the efficacy of potential new diagnostic and/or therapeutic biomarkers.

Cyclin D1, p53, and p21Waf1/Cip1 expression is predictive of poor clinical outcome in serous epithelial ovarian cancer

PURPOSE

Dysregulation of cell cycle control, in particular G(1)-S-phase transition, is implicated in the pathogenesis of most human cancers, including epithelial ovarian cancer (EOC). However, the prognostic significance of aberrant cell cycle gene expression in EOC remains unclear.

EXPERIMENTAL DESIGN

The expression of selected genes from the pRb pathway that regulates G(1)-S-phase progression, including cyclin D1, p16(Ink4a), cyclin E, p27(Kip1), p21(Waf1/Cip1), and p53, was examined in a consecutive series of 134 serous EOC using immunohistochemistry and the results correlated to disease outcome.

RESULTS

Molecular markers predictive of reduced overall survival in univariate analysis were overexpression of cyclin D1 (P = 0.03) and p53 (P = 0.03) and reduced expression of p27(Kip1) (P = 0.05) and p21(Waf1/Cip1) (P = 0.02), with the latter three also being prognostic for a shorter progression-free interval. In addition, patients displaying overexpression of p53 with concurrent loss of p21(Waf1/Cip1) had a significantly shorter overall (P = 0.0008) and progression-free survival (P = 0.0001). On multivariate analysis, overexpression of cyclin D1 and combined loss of p21(Waf1/Cip1) in the presence of p53 overexpression were independent predictors of overall survival. Similarly, the combination of p21(Waf1/Cip1) loss and p53 overexpression was independently predictive of a shorter progression-free interval. Overexpression of p53 and cyclin E and reduced expression of p27(Kip1) and p21(Waf1/Cip1) were significantly associated with increasing tumor grade.

CONCLUSIONS

This study confirms that dysregulation of cell cycle genes is common in EOC, and that aberrant expression of critical cell cycle regulatory proteins can predict patient outcome in serous EOC.

Expression of p57kip2 and its relationship with clinicopathology, PCNA and p53 in primary hepatocellular carcinoma

AIM: To investigate the expression of p57^kip2 and its relationship with clinicopathology, PCNA and p53 in primary hepatocellular carcinoma (HCC).

METHODS: Expression of p57^kip2, PCNA and p53 in tumor tissues from 32 patients with HCC and 10 liver tissues of normal persons was detected with Elivision immunohistochemical technique.

RESULTS: The p57^kip2 protein positive-expression rate in HCC was 56.25%, lower than that in normal tissues (100%, P<0.05). The reduced expression of p57^kip2 protein correlated significantly with moderate or low differentiation of tumor cells (P = 0.007 <0.05), high clinical stage (P = 0.041 <0.05) and poor prognosis (P = 0.036 <0.05), but did not correlate significantly with metastasis, tumor size, level of AFP and age (P>0.05). The PCNA positive-expression rate was 56.25%, which was correlated significantly with the expression of p57^kip2 (P = 0.025<0.05). The p53 positive-expression rate was 46.88%, which was not correlated significantly with the expression of p57^kip2 (P>0.05).

CONCLUSION: There is a marked loss or absence of p57^kip2 expression and high expression of PCNA in HCC, which are involved in carcinogenesis and development of HCC. The p57^kip2 and p53 may induce apoptosis via different mechanisms.

Cyclin E Amplification and Overexpression in Clear Cell Adenocarcinoma of the Ovary

OBJECTIVE

The purpose of this study is to compare DNA, mRNA and protein levels of the cyclin E between clear cell (CC) and serous (SC) ovarian carcinomas, and evaluate the relationship between cyclin E and p53 status.

METHOD

We examined the DNA, mRNA and protein levels of cyclin E and the protein level of p53 in 44 CCs and 39 SCs using microdissected tissues.

RESULTS

Relative cyclin E mRNA expression was significantly higher in CC (3.62, 95% CI, 2.24-4.99) than in SC (1.75, 95% CI, 1.05-2.45; p = 0.0098). The percentage of positive nuclear staining of cyclin E was significantly higher in CC (48.3, 95% CI, 40.4-56.1) than SC (25.3, 95% CI, 17.4-33.3; p = 0.0001). The mRNA and protein expression of cyclin E was significantly correlated (r = 0.66, p < 0.0001). However, the correlation between relative DNA copy number and relative mRNA expression was not significant (r = -0.063; p = 0.66). Percentage of positive nuclear staining of cyclin E was significantly higher in p53 positive cases (51.8, 95% CI, 40.0-63.5) than p53 negative cases (36.2, 95% CI, 28.2-44.2; p = 0.028).

CONCLUSIONS

Cyclin E expression is significantly higher in CC than in SC. Cyclin E expression is significantly related with p53 positivity.

Inducible expression of p57KIP2 inhibits glioma cell motility and invasion

To examine the role of p57KIP2 in human malignant glioma cells, we studied its expression in a panel of human malignant glioma specimens by western blot and immunohistochemical analysis. To determine the effects of p57KIP2 expression on the phenotype of glioma cells, we analyzed two inducible stably transfected p57KIP2 expressing glioma cell lines. Expression of p57KIP2 was induced in U373 and U87 malignant glioma cells with doxycycline using the tetracycline repressor system. A phagokinetic track assay on gold particles was used to investigate differences in cell migration between p57KIP2 expressing and non-expressing control cells. The effects of the extracellular matrix (ECM) on U373 motility was determined in p57+ and p57-cells on surfaces coated with 5 microg/cm2 of fibronectin, laminin, type I and type IV collagens. The invasion of p57+ and p57- glioma cells across BD Biocoat Matrigel invasion chambers was then determined. p57KIP2 was weakly expressed in 4/6 glioblastoma (GBM) specimens by western blot. By immunohistochemistry, p57KIP2 immunoreactivity was positive in 8/40 GBMs, and was primarily nuclear in location. The motility of U373 glioma cells was significantly reduced after p57KIP2 induction. The presence of ECM proteins did not further alter the motility of p57+ and p57- glioma cells. The results of the invasion chamber assay showed that p57+ cells exhibited a 35% reduction in their invasive capacity as compared to p57- cells. These data suggest that p57KIP2 is expressed in at least some malignant gliomas. Inducible expression of 57KIP2 in cell lines deficient in this cyclin-dependent kinase inhibitor reduces their otility and invasiveness.

p57KIP2 immunohistochemical staining of gestational trophoblastic tumours does not identify the type of the causative pregnancy

AIM

To determine whether immunohistochemical staining for p57(KIP2), the product of the maternally expressed gene CDKN1C, can be used to differentiate between gestational trophoblastic tumours arising from a complete hydatidiform mole and those originating from non-molar pregnancies.

METHODS

The immunohistochemical expression of p57(KIP2) was investigated in 23 cases of choriocarcinoma and 17 placental site trophoblastic tumours. Fourteen of the tumours examined were shown by DNA analysis to have arisen from complete hydatidiform moles and 26 from non-molar pregnancies.

RESULTS

Five of 11 (45%) post-complete hydatidiform mole choriocarcinomas and two of three (67%) post-complete hydatidiform mole placental site trophoblastic tumours were found to be p57(KIP2)+ and showed similar immunostaining characteristics to tumours that developed from non-molar pregnancies. Although there was a statistically significant reduction in the proportion of cases showing positive p57(KIP2) staining in post-complete hydatidiform mole tumours compared with those originating in non-molar pregnancies [proportion difference 0.35 [95% confidence interval (CI) 0.05, 0.61], P = 0.02], immunostaining did not provide diagnostically useful information to differentiate between these tumours in clinical practice. There was no significant difference between the extent of staining in choriocarcinoma versus placental site trophoblastic tumours [proportion difference 0.17 (95% CI - 12, 42), P = 0.19]. The majority of both types of gestational trophoblastic tumour were positive for the presence of the p57(KIP2) protein irrespective of their genetic origin.

CONCLUSION

Immunostaining for p57(KIP2) fails to discriminate between gestational trophoblastic tumours that have arisen from complete hydatidiform moles and those that have originated from other types of pregnancy.

Activation of the protein kinase A pathway in human endometrial stromal cells reveals sequential categorical gene regulation

Decidualization of endometrial stromal cells is a prerequisite for human implantation and occurs in vivo in response to progesterone and involves activation of the protein kinase A (PKA) pathway. The objective of this study was to determine the molecular signatures and patterns of gene expression during stimulation of this pathway with an analog of cAMP. Endometrial stromal cells from two subjects were treated with or without 8-Br-cAMP (1 mM) for 0, 2, 12, 24, 36, and 48 h and were processed for microarray analysis, screening for 12,686 genes and ESTs. Most abundantly upregulated genes included neuropeptides, immune genes, IGF family members, cell cycle regulators, extracellular matrix proteases, cholesterol trafficking, cell growth and differentiation, hormone signaling, and signal transduction. Most abundantly downregulated genes included activator of NF-kappaB, actin/tropomyosin/calmodulin binding protein, cyclin B, IGFBP-5, alpha1 type XVI collagen, lipocortin III, l-kynurenine hydrolase, frizzle-related protein, and cyclin E2. RT-PCR validated upregulation of IGFBP-1, preprosomatostatin, and IL-11, and Northern analysis validated their kinetic upregulation. RT-PCR confirmed downregulation of IGFBP-5, cyclin B, and TIL-4. K-means analysis revealed four major patterns of up- and downregulated genes, and genes within each ontological group were categorized into these four kinetic patterns. Within each ontological group different patterns of temporal gene expression were observed, indicating that even genes within one functional category are regulated differently during activation of the PKA pathway in human endometrial stromal cells. Overall, the data demonstrate kinetic reprogramming of genes within specific functional groups and changes in genes associated with nucleic acid binding, cell proliferation, decreased G protein signaling, increased STAT pathway signaling, structural proteins, cellular differentiation, and secretory processes. These changes are consistent with cAMP modulating early events (0-6 h) primarily involving cell cycle regulation, subsequent events (12-24 h) involving cellular differentiation (including changes in morphology and secretory phenotype), and late events (24-48 h) mediating more specialized function, including immune modulators, in the human endometrial stromal cell.

Targeted therapy for epithelial ovarian cancer: Current status and future prospects

Despite advances in surgery and chemotherapy, less than 20% of patients with stage III or IV ovarian cancer survive long-term. In the past, cytotoxic regimens have been developed empirically, combining active agents at maximally tolerated doses, often without a clear rationale for their interaction. Advances in understanding the biology of ovarian cancer have identified multiple molecular targets that differ in normal and malignant cells. Targets include cell cycle regulators, growth factor receptors, signal transduction pathways, molecules that confer drug resistance, and angiogenic mechanisms. A number of targeted agents have entered clinical trials. Small molecular weight inhibitors, monoclonal antibodies, and antisense and gene therapy are all being evaluated alone and in combination with cytotoxic drugs. In contrast to earlier studies, the impact of each agent on the designated target can be assessed and agents can be matched to the genotype and phenotype of malignant and normal cells. In the long run, this should facilitate individualization of more effective, less toxic therapy for women with ovarian cancer.

Role of cell-cycle regulatory proteins in gynecological cancer

Human malignant tumors are characterized by abnormal proliferation resulting from alterations in cell-cycle regulatory mechanisms. This review summarizes the current knowledge about these aberrations in malignant tumors of the ovary, endometrium, cervix uteri, and vulva. The data indicate that analysis of single cell cycle stimulating or inhibiting proteins partly produces unexpected, apparently paradoxical results, and cell-cycle regulatory pathways should be regarded as a whole in order to identify the molecular mechanisms leading to abnormal tumor cell proliferation. For the papillomavirus (HPV)- associated cervical and vulvar carcinomas, the manifold effects of the viral oncogenes E6 and E7 on cell-cycle control are described.

Expressions of the CIP/KIP family of CDK inhibitor proteins in primary intestinal large B-cell lymphomas: correlation with clinical outcomes

Immunohistochemistry was performed for p21, p27, p57 and p53 on paraffin-embedded tissue sections from 25 patients who had surgically resected intestinal lymphomas. It was then correlated with the patients' clinical course in an attempt to determine the expression patterns and clinical significance of the CIP/KIP family of cyclin-dependent kinase inhibitors in primary intestinal large B-cell lymphomas. p21 immunostaining was positive in 11 cases (44%) and p27 was positive in 8 cases (32%). All cases were p57-negative. p53 immunostaining was positive in 14 cases (56%) and negative in 11 cases (44%). With respect to the relationship between p21 and p53, seven cases were p53+/p21-, seven cases were p53+/p21+, seven cases were p53-/p2l-, and four cases were p53-/p21+. The expression patterns of p21 and p53 did not influence the patient's clinical outcome. However, p27-positive cases had a much higher percentage of patients sustaining a continuous complete remission state (8/8, 100%) as compared to p27-negative cases (10/17, 59%), although this difference was not statistically significant (p = 0.057). These results suggest that p27 immunoreactivity may be associated with a better clinical outcome. However, further study with larger series are planned to determine the clinical significance of p27 overexpression in primary intestinal large B-cell lymphomas.

Aberrant DNA methylation of p57KIP2 identifies a cell-cycle regulatory pathway with prognostic impact in adult acute lymphocytic leukemia

P57KIP2 is a cyclin-dependent kinase inhibitor silenced in a variety of human malignancies. DNA methylation of a region surrounding the transcription start site of p57KIP2 was found in acute lymphocytic leukemia (ALL)-derived cell lines. Methylation of this region correlated with gene silencing, and treatment of methylated/silenced cell lines with 5-aza-2'-deoxycytidine resulted in gene re-expression. P57KIP2 was methylated in 31 (50%) of 63 patients with newly diagnosed ALL, and in 11 (52%) of 21 patients with relapsed ALL. In 5 of them (25%), methylation was acquired at relapse. No association was observed between methylation of p57KIP2 alone and clinical-biologic characteristics studied, including overall survival (OS) or disease-free survival. Methylation of multiple genes in a cell-cycle regulatory pathway composed of p73, p15, and p57KIP2 occurred in 22% of Philadelphia chromosome (Ph)-negative patients. Ph-negative patients with methylation of 2 or 3 genes of this pathway had a significantly worse median OS compared with those with methylation of 0 or 1 gene (50 vs 467 weeks, respectively; P =.02). Our results indicate that p57KIP2 is frequently methylated in adult patients with ALL, and that inactivation of a pathway composed of p73, p15, and p57KIP2 predicts for poor prognosis in Ph-negative patients.

Expression and prognostic value of the cell-cycle regulatory proteins, Rb, p16MTS1, p21WAF1, p27KIP1, cyclin E, and cyclin D2, in ovarian cancer

To investigate the role of cell-cycle regulatory proteins in ovarian cancer, we performed immunohistochemistry for the cell-cycle promoters cyclin E and cyclin D2 and the cell-cycle inhibitors, Rb, p16MTS1, p21WAF1, and p27 KIP1, in 93 ovarian carcinomas (77 with follow-up data). The results were correlated with clinicopathological parameters and the prognostic value was determined by multivariate analysis. Strong Rb and moderate-high cyclin E immunoreactivity in carcinomas were weakly associated with high expression of the proliferation marker Ki67. By Cox's multivariate analysis, advanced stage (p=0.013), strong Rb expression (p=0.006), and negative-weak p21 staining (p=0.011) were independent prognostic indicators of short overall survival, indicating an apparently paradoxical role of the retinoblastoma protein in these tumors. In addition, trends pointing to an association of higher age (p=0.067) and positive cyclin E immunoreactivity (p=0.093) with an unfavorable prognosis were observed.

Expression of p57kip2 and p27kip1 proteins and its relationship with clinicopathology in human pancreatic cancer

AIM: To investigate the effects of p57^kip2 and p27^kip1 proteins on the development and progression of pancreatic cancer.

METHODS: Expression of p57^kip2 and p27^kip1 proteins in tumor and adjacent tissues of 32 patients with pancreatic cancer were detected by SP immunohistochemical technique.

RESULTS: p57^kip2 protein positive rate in tumor tissues of pancreatic cancer was 46.9%, which was lower than that in adjacent pancreatic tissues (75.0%)(x² = 5.317, P < 0.05), p57^kip2 protein expression correlated remarkably with tumor cell differentiation (x² = 4.979, P < 0.05), but did not correlate with lymph node metastasis (x² = 3.698, P < 0.05); p27^kip1 protein positive rate in the tumor tissues was 56.3%, which was lower than that in adjacent pancreatic tissues (84.4%) (x² = 6.063, P < 0.05). p27^kip1 expression was correlated remarkably with tumor cell differentiation and lymph node metastasis (x² = 5.776; x² = 4.097, P < 0.05). p57^kip2 protein positive rate (50.0%) in p27^kip1 protein positive group was higher than that (42.9%) in p27^kip1 protein negative group, and there was no significant correlation between the two groups (r = 0.19657, P > 0.05).

CONCLUSION: p57^kip2 and p27^kip1 proteins may play an important role in carcinogenesis and progression of human pancreatic cancer. Decreased expression of p57^kip2 and p27^kip1 proteins is subject to the development of pancreatic cancer and determination of cell differentiation degree, and helpful to evaluate prognosis of the diseases.

Expression of p57kip2, Rb protein and PCNA and their relationships with clinicopathology in human pancreatic cancer

AIM: To investigate the effects of inhibiting factor of cell cycle regulation p57^kip2, retinoblastinoma protein (Rb protein) and proliferating cell nuclear antigen (PCNA) in the genesis and progression of human pancreatic cancer.

METHODS: The expression of p57^kip2, Rb protein and PCNA in tumor tissues and adjacent tissues of 32 patients with pancreatic cancer was detected with SP immunohistochemical technique.

RESULTS: p57^kip2 protein positive-expression rate in tumor tissues of pancreatic cancer was 46.9%, which was lower than that in adjacent pancreatic tissues (75.0%) (χ² = 5.317, P < 0.05), p57^kip2 protein positive-expression correlated significantly with tumor cell differentiation (well-differentiation versus moderate or low-differentiation, P < 0.05) but did not correlate significantly with lymph node metastasis (lymph node metastasis versus non-lymph node metastasis, P > 0.05); Rb gene protein positive-expression rate in tumor tissues was 50.0%, which was also lower than that in adjacent pancreatic tissues (78.1%) (χ² = 5.497, P < 0.05); PCNA positive-expression rate was 71.9%, being higher than that in adjacent pancreatic tissues (43.8%) (χ² = 5.189, P < 0.05), PCNA positive-expression also correlated significantly with tumor cell differentiation and lymph node metastasis (well-differentiation versus moderate or low- differentiation, lymph node metastasis versus non-lymph node metastasis, P < 0.05). Rb protein positive-expression rate in the tumor tissues of p57^kip2 protein positive-expression group was 53.3%; and Rb protein positive-expression rate in the tumor tissues of p57^kip2 protein negative-expression group was 47.1%. There was no significant relationship between the two groups (r = 0.16507, P > 0.05).

CONCLUSION: The decreased expression of p57^kip2, Rb protein or over-expression of PCNA protein might contribute to the genesis or progression of pancreatic cancer, p57^kip2, Rb protein and PCNA may play an important role in genesis and progression of pancreatic cancer.