Alteration of cell-cycle regulation in epithelial ovarian cancer

Long Non-Coding RNAs in Ovarian Cancer: Mechanistic Insights and Clinical Applications

Background/Objectives: Ovarian cancer is a leading cause of gynecological cancer mortality worldwide, often diagnosed at advanced stages due to vague symptoms and the lack of effective early detection methods. Long non-coding RNAs (lncRNAs) have emerged as key regulators in cancer biology, influencing cellular processes such as proliferation, apoptosis, and chemoresistance. This review explores the multifaceted roles of lncRNAs in ovarian cancer pathogenesis and their potential as biomarkers and therapeutic targets. Methods: A comprehensive literature review was conducted to analyze the structural and functional characteristics of lncRNAs and their contributions to ovarian cancer biology. This includes their regulatory mechanisms, interactions with signaling pathways, and implications for therapeutic resistance. Advanced bioinformatics and omics approaches were also evaluated for their potential in lncRNA research. Results: The review highlights the dual role of lncRNAs as oncogenes and tumor suppressors, modulating processes such as cell proliferation, invasion, and angiogenesis. Specific lncRNAs, such as HOTAIR and GAS5, demonstrate significant potential as diagnostic biomarkers and therapeutic targets. Emerging technologies, such as single-cell sequencing, provide valuable insights into the tumor microenvironment and the heterogeneity of lncRNA expression. Conclusions: LncRNAs hold transformative potential in advancing ovarian cancer diagnosis, prognosis, and treatment. Targeting lncRNAs or their associated pathways offers promising strategies to overcome therapy resistance and enhance personalized medicine. Continued research integrating omics and bioinformatics will be essential to unlock the full clinical potential of lncRNAs in ovarian cancer management.

The Clinicopathological Significance of the Cyclin D1/E1-Cyclin-Dependent Kinase (CDK2/4/6)-Retinoblastoma (RB1/pRB1) Pathway in Epithelial Ovarian Cancers

Cyclin-dependent kinases (CDK2, CDK4, CDK6), cyclin D1, cyclin E1 and phosphorylated retinoblastoma (pRB1) are key regulators of the G1/S cell cycle checkpoint and may influence platinum response in ovarian cancers. CDK2/4/6 inhibitors are emerging targets in ovarian cancer therapeutics. In the current study, we evaluated the prognostic and predictive significance of the CDK2/4/6-cyclin D1/E1-pRB1 axis in clinical ovarian cancers (OC). The CDK2/4/6, cyclin D1/E1 and RB1/pRB1 protein expression were investigated in 300 ovarian cancers and correlated with clinicopathological parameters and patient outcomes. CDK2/4/6, cyclin D1/E1 and RB1 mRNA expression were evaluated in the publicly available ovarian TCGA dataset. We observed nuclear and cytoplasmic staining for CDK2/4/6, cyclins D1/E1 and RB1/pRB1 in OCs with varying percentages. Increased nuclear CDK2 and nuclear cyclin E1 expression was linked with poor progression-free survival (PFS) and a shorter overall survival (OS). Nuclear CDK6 was associated with poor OS. The cytoplasmic expression of CDK4, cyclin D1 and cyclin E1 also has predictive and/or prognostic significance in OCs. In the multivariate analysis, nuclear cyclin E1 was an independent predictor of poor PFS. Tumours with high nuclear cyclin E1/high nuclear CDK2 have a worse PFS and OS. Detailed bioinformatics in the TCGA cohort showed a positive correlation between cyclin E1 and CDK2. We also showed that cyclin-E1-overexpressing tumours are enriched for genes involved in insulin signalling and release. Our data not only identified the prognostic/predictive significance of these key cell cycle regulators but also demonstrate the importance of sub-cellular localisation. CDK2 targeting in cyclin-E1-amplified OCs could be a rational approach.

Exposure to Cadmium Telluride Quantum Dots and Gene Expression Profile of Huh-7 Hepatocellular Carcinoma Cell Line

Nanoparticles have shown promising potential for efficient drug delivery, circumventing biological interferences like immunological and renal clearance and mechanical and enzymatic destruction. However, a handful of research papers have questioned the biomedical use of metal-based nanoparticles like cadmium telluride quantum dots (CdTe-QDs) for their cytotoxic, genotoxic, and carcinogenic potential. Herein, we examined the effects of CdTe-QD NPs on gene expression profile of hepatocellular carcinoma (Huh-7) cell line. Huh-7 cells were treated with CdTe-QD NPs (10 μg/ml for 6, 12, and 24 hours, and 25 μg/ml for 6 and 12 hours), and transcriptomic analysis was performed using microarray to evaluate the global gene expression profile. Differential expressed genes (DEGs) were observed for both the doses (10 and 25 μg/ml) of CdTe-QD NPs at different time points. Gene ontology (GO) analysis revealed that genes involved in molecular function of cell cycle, organizational injury and abnormalities, cell death and survival, gene expression, cancer, organismal survival, and cellular development were differentially expressed. Overall, we have demonstrated differential expression of several genes, involved in maintaining cell survival, metabolism, and genome integrity. These findings were confirmed by RT-qPCR study for some canonical pathway genes signifying possible implication in NP toxicity-mediated cell survival and inhibition of cell death.

Association between CDKN1A gene rs1801270 polymorphisms and susceptibility to colorectal cancser in an Iranian population

CDKN1A gene is implicated in cell differentiation, development process, repair, apoptosis, senescence, migration, and tumorigenesis. Somatic alterations and polymorphisms may interfere in the function of CDKN1A, and this could affect the individual susceptibility to colorectal cancer (CRC). Here in, we evaluated the importance of single nucleotide polymorphic variants in codon 31 of CDKN1A (rs1801270: C > A) for the development of colorectal cancer in an Iranian population. A total of 150 CRC patients and 150 healthy controls were enrolled in this study. Genomic DNA was extracted from peripheral blood specimens. Genotypes were determined using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay. In CRC patients, the genotype frequencies detected were 90%, 8.0% and 2.0%2 for CC, AC and AA genotypes while the genotype frequencies in control group were 78%, 20.7% and 1.35% 1.35% for CC, AC and AA genotype, respectively. There were statistically significant differences in the distribution of CDKN1A rs1801270 genotypes and allele frequencies between colorectal cancer patients and healthy controls (p value = 0.021). Also, results indicated a significant negative association between AC genotype and risk of colorectal cancer occurrence. (Odds ratio (OR)=0.357; 95% confidence interval (CI)=0.168-0.760, p = 0.007). Our data suggest that the AC genotype may have a protective role in the development of CRC in an Iranian population.

Effect of butyrate, a bacterial by-product, on the viability and ICAM-1 expression/production of human vascular endothelial cells: Role in infectious pulpal/periapical diseases

AIM

To investigate the effects of butyric acid (BA), a metabolic product generated by pulp and root canal pathogens, on the viability and intercellular adhesion molecule-1 (ICAM-1) production of endothelial cells, which are crucial to angiogenesis and pulpal/periapical wound healing.

METHODOLOGY

Endothelial cells were exposed to butyrate with/without inhibitors. Cell viability, apoptosis and reactive oxygen species (ROS) were evaluated using an MTT assay, PI/annexin V and DCF fluorescence flow cytometry respectively. RNA and protein expression was determined using a polymerase chain reaction assay and Western blotting or immunofluorescent staining. Soluble ICAM-1 (sICAM-1) was measured using an enzyme-linked immunosorbent assay. The quantitative results were expressed as mean ± standard error (SE) of the mean. The data were analysed using a paired Student's t-test where necessary. A p-value ≤0.05 was considered to indicate a statistically significant difference between groups.

RESULTS

Butyrate (>4 mM) inhibited cell viability and induced cellular apoptosis and necrosis. It inhibited cyclin B1 but stimulated p21 and p27 expression. Butyrate stimulated ROS production and hemeoxygenase-1 (HO-1) expression as well as activated the Ac-H3, p-ATM, p-ATR, p-Chk1, p-Chk2, p-p38 and p-Akt expression of endothelial cells. Butyrate stimulated ICAM-1 mRNA/protein expression and significant sICAM-1 production (p < .05). Superoxide dismutase, 5z-7oxozeaenol, SB203580 and compound C (p <  .05), but not ZnPP, CGK733, AZD7762 or LY294002, attenuated butyrate cytotoxicity to endothelial cells. Notably, little effect on butyrate-stimulated sICAM-1 secretion was found. Valproic acid, phenylbutyrate and trichostatin (three histone deacetylase inhibitors) significantly induced sICAM-1 production (p < .05).

CONCLUSION

Butyric acid inhibited proliferation, induced apoptosis, stimulated ROS and HO-1 production and increased ICAM-1 mRNA expression and protein synthesis in endothelial cells. Cell viability affected by BA was diminished by some inhibitors; however, the increased sICAM-1 secretion by BA was not affected by any of the tested inhibitors. These results facilitate understanding of the pathogenesis, prevention and treatment of pulpal/periapical diseases.

Effects of Iron Chelation in Osteosarcoma

BACKGROUND

Osteosarcoma is an aggressive bone tumor. It represents the principal cause of cancer-associated death in children. Considering the recent findings on the role of iron in cancer, iron chelation has been investigated for its antineoplastic properties in many tumors. Deferasirox is the most used iron chelator compound and in previous studies showed an anticancer effect in hematologic and solid malignancies. Eltrombopag is a Thrombopoietin receptor used in thrombocytopenia that also binds and mobilize iron. It demonstrated an effect on iron overload conditions and also in contrasting cancer cell proliferation.

OBJECTIVE

We analyzed the effects of deferasirox and eltrombopag in human osteosarcoma cells in an attempt to identify other therapeutic approaches for this tumor.

METHODS

We cultured and treated with deferasirox and Eltrombopag, alone and in combination, two human osteosarcoma cell lines, MG63 and 143B. After 72h exposure, we performed RTqPCR, Western Blotting, Iron Assay and cytofluorimetric assays to evaluate the effect on viability, apoptosis, cell cycle progression and ROS production.

RESULTS

The iron-chelating properties of the two compounds are also confirmed in osteosarcoma, but we did not observe any direct effect on tumor progression.

DISCUSSION

We tested deferasirox and eltrombopag, alone and in combination, in human osteosarcoma cells for the first time and demonstrated that their iron-chelating activity does not influence biochemical pathways related to cancer progression and maintenance.

CONCLUSION

Although further investigations on possible effects mediated by cells of the tumor microenvironment could be of great interest, in vitro iron chelation in osteosarcoma does not impair tumor progression.

Sulforaphane-cysteine downregulates CDK4 /CDK6 and inhibits tubulin polymerization contributing to cell cycle arrest and apoptosis in human glioblastoma cells

Here we demonstrated that sulforaphane-cysteine (SFN-Cys) regulated cell cycle-related protein expressions in G0/G1 and G2/M phases of U87MG cells via High Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (HPLC-MS/MS) and proteomics analysis. Further, mRNA products of CDK4, CDK6 and α-tubulin were significantly higher in glioblastoma than those in normal tissues, and these results were significantly correlated to pathological grades and clinical prognosis via analyzing TCGA and CGGA databases. Furthermore, Western blot showed that SFN-Cys downregulated CDK4, CDK6 and p-Rb in a dose-dependent manner and these results were reversed by p-ERK1/2 blocker PD98059 in U87MG and U373MG cells. The reductions of CDK4, CDK6 and p-Rb were reversed by proteasome inhibitor MG132; similarly, the upregulation of 26S proteasome by SFN-Cys was reversed by PD98059. Interestingly, SFN-Cys decreased CDK4 and CDK6 by phosphorylated ERK1/2-caused proteasomal degradation resulting in decreased Rb phosphorylation contributing to cell cycle arrest in G0/G1 phase. Besides, Western blot showed that SFN-Cys downregulated α-tubulin resulting in microtubule disruption and aggregation, and cell cycle arrest in G2/M phase and apoptosis. These results might help us understand the molecular etiology of glioblastoma progression to establish brand-new anti-cancer therapies.

CDK4/6 inhibition promotes immune infiltration in ovarian cancer and synergizes with PD-1 blockade in a B cell-dependent manner

Great progress has been made in the field of tumor immunotherapy in the past decade. However, the therapeutic effects of immune checkpoint blockade (ICB) against ovarian cancer are still limited. Recently, an inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6i) has been reported to enhance antitumor immunity in preclinical models. The combined use of CDK4/6i and ICB may be beneficial, but the effects of CDK4/6is on the tumor immune microenvironment and whether they can synergize with ICB in treating ovarian cancer remain unknown. Methods: In this study, we first assessed the antitumor efficacy of abemaciclib, an FDA-approved CDK4/6i, in a syngeneic murine ovarian cancer model. Then, immunohistochemistry, immunofluorescence and flow cytometry were performed to evaluate the number, proportion, and activity of tumor-infiltrating lymphocytes. Cytokine and chemokine production was detected both in vivo and in vitro by PCR array analysis and cytokine antibody arrays. The treatment efficacy of combined abemaciclib and anti-PD-1 therapy was evaluated in vivo, and CD8+ and CD4+ T cell activities were analyzed using flow cytometry. Lastly, the requirement for both CD8+ T cells and B cells in combination treatment was evaluated in vivo, and potential cellular mechanisms were further analyzed by flow cytometry. Results: We observed that abemaciclib monotherapy could enhance immune infiltration, especially CD8+ T cell and B cell infiltration, in the ID8 murine ovarian cancer model. Immunophenotyping analysis showed that abemaciclib induced a proinflammatory immune response in the tumor microenvironment. PCR array analysis suggested the presence of a Th1-polarized cytokine profile in abemaciclib-treated ID8 tumors. In vitro studies showed that abemaciclib-treated ID8 cells secreted more CXCL10 and CXCL13, thus recruiting more lymphocytes than control groups. Combination treatment achieved better tumor control than monotherapy, and the activities of CD8+ and CD4+ T cells were further enhanced when compared with monotherapy. The synergistic antitumor effects of combined abemaciclib and anti-PD-1 therapy depended on both CD8+ T cells and B cells. Conclusion: These findings suggest that combined treatment with CDK4/6i and anti-PD-1 antibody could improve the efficacy of anti-PD-1 therapy and hold great promise for the treatment of poorly immune-infiltrated ovarian cancer.

An Overview of Candidate Therapeutic Target Genes in Ovarian Cancer

Ovarian cancer (OC) shows the highest mortality rate among gynecological malignancies and, because of the absence of specific symptoms, it is frequently diagnosed at an advanced stage, mainly due to the lack of specific and early biomarkers, such as those based on cancer molecular signature identification. Indeed, although significant progress has been made toward improving the clinical outcome of other cancers, rates of mortality for OC are essentially unchanged since 1980, suggesting the need of new approaches to identify and characterize the molecular mechanisms underlying pathogenesis and progression of these malignancies. In addition, due to the low response rate and the high frequency of resistance to current treatments, emerging therapeutic strategies against OC focus on targeting single factors and pathways specifically involved in tumor growth and metastasis. To date, loss-of-function screenings are extensively applied to identify key drug targets in cancer, seeking for more effective, disease-tailored treatments to overcome lack of response or resistance to current therapies. We review here the information relative to essential genes and functional pathways recently discovered in OC, often strictly interconnected with each other and representing promising biomarkers and molecular targets to treat these malignancies.

α-bisabolol enhances radiotherapy-induced apoptosis in endometrial cancer cells by reducing the effect of XIAP on inhibiting caspase-3

Endometrial cancer (EC) is one of the most common cancers in females. Although the diagnosis and treatment in early stages can greatly improve the survival rate of patients, the advanced EC still is lethal. Radiotherapy is widely used against EC, and it is a great challenge to find an effective way to overcome the resistance of EC during radiotherapy. α-bisabolol is a promising drug, which has already exhibited its anti-tumor effect in some malignancies. Here we reported that α-bisabolol could inhibit the proliferation of EC cells. It is also shown that their abilities of migration and invasion were effectively reduced by α-bisabolol. Furthermore, our results also demonstrated that α-bisabolol could improve sensitivity of EC cells in radiotherapy and further inhibited the growth of EC cells. By Western blot, we found the expression of matrix metalloproteinases-9 (MMP-9) and cyclin E were significantly decreased, which indicated that EC cells can be further suppressed by using α-bisabolol and radiotherapy. It is also demonstrated in our study that the rate of apoptotic cells is markedly increased in EC by using these two treatments. The significant decrease in X-linked inhibitor of apoptosis protein (XIAP) and increase in caspase-3 detected in our study suggested that the enhancement of apoptosis is mediated by XIAP/caspase-3 pathway, which was further confirmed by examining the downstream effectors of caspase-3, COX-2, PARP and cleaved PARP. In the present study, we demonstrated that α-bisabolol could enhance the sensitivity of EC cells to radiotherapy, which provide a novel alternative for overcoming radioresistance of EC cells and achieving a better outcome in radiotherapy.

Different Lipid Regulation in Ovarian Cancer: Inhibition of the Immune System

Lipid metabolism is altered in several cancer settings leading to different ratios of intermediates. Ovarian cancer is the most lethal gynecological malignancy. Cancer cells disperse in the abdominal space and ascites occurs. T cells obtained from ascites are unable to proliferate after an antigenic stimulus. The proliferation of ascites-derived T cells can be restored after culturing the cells for ten days in normal culture medium. No pathway aberrancies were detected. The acellular fraction of ascites can inhibit the proliferation of autologous as well as allogeneic peripheral blood lymphocytes, indicating the presence of soluble factors that interfere with T cell functionality. Therefore, we analyzed 109 lipid mediators and found differentially regulated lipids in suppressive ascitic fluid compared to normal abdominal fluid. Our study indicates the presence of lipid intermediates in ascites of ovarian cancer patients, which coincidences with T cell dysfunctionality. Since the immune system in the abdominal cavity is compromised, this may explain the high seeding efficiency of disseminated tumor cells. Further research is needed to fully understand the correlation between the various lipids and T cell proliferation, which could lead to new treatment options.

Tribbles 2 mediates cisplatin sensitivity and DNA damage response in epithelial ovarian cancer

Aim was to identify methylated genes with functional involvement in cisplatin-resistance development of epithelial ovarian cancer (EOC). Genome-wide analyses of hypermethylated CpG-islands in resistant cell lines in combination with qRT-PCR analyses were used to identify epigenetically silenced genes. EOC-Type-II tumors were analyzed for gene methylation and expression and TCGA data were interrogated in-silico. Experiments revealed 37 commonly hypermethylated genes in resistant cells of which Tribbles 2 (TRIB2) showed the most pronounced downregulation on mRNA level and was characterized further. TRIB2 showed a reactivation after 5'-Aza-Cytidine treatment in resistant cells but a cisplatin-dependent, prominent upregulation on mRNA level in sensitive cells, only. Re-expression in resistant A2780 cells increased the sensitivity to cisplatin and other DNA-damaging agents, but not taxanes. Contrary, knockdown of TRIB2 increased resistance to cisplatin in sensitive cells. TRIB2 was involved in the induction of a cisplatin-dependent cell cycle arrest and apoptosis by influencing p21 and survivin expression. An increased Pt-DNA-adduct formation in TRIB2 re-expressing cells did not translate in higher levels of dsDNA damage (yH2AX-foci). Thus, TRIB2 is potentially involved in the signal transduction from nucleotide excision repair of intrastrand cross links. Importantly, patient stratification of two homogenous cohorts of EOC-Type-II patients from Jena (n = 38) and the TCGA (n = 149) by TRIB2 mRNA expression consistently revealed a significantly decreased PFS for patients with low TRIB2 levels (log-rank p < 0.05). Tumors from resistant patients expressed the lowest levels of TRIB2. Downregulation of TRIB2 contributes to platin-resistance and TRIB2 expression should be validated as prognostic and predictive marker for EOC.

E2F transcription factor 2 variants as predictive biomarkers for recurrence risk in patients with squamous cell carcinoma of the oropharynx

Because E2F transcription factor 2 (E2F2) promoter polymorphisms have been implicated in carcinogenesis and prognosis, we investigated associations between genetic variants in five E2F2 promoter polymorphisms and recurrence risk of squamous cell carcinoma of the oropharynx (SCCOP) in 1 008 patients. A log-rank test and multivariable Cox models were used to assess the associations. Compared with patients with variant genotypes of E2F2-rs2742976 and E2F2-rs3218123, patients with common homozygous genotypes had better disease-free survival (both log-rank, P < 0.001) and lower SCCOP recurrence risk (HR, 0.4, 95% CI, 0.3-0.6 and HR, 0.3, 95% CI, 0.2-0.5, respectively) after multivariable adjustment. Furthermore, among patients with HPV16-positive tumors, those with common homozygous genotypes of E2F2-rs2742976 and E2F2-rs3218123 had better disease-free survival rates (both log-rank, P < 0.001) and lower recurrence risk (HR, 0.1, 95% CI, 0.1-0.4 and HR, 0.1, 95% CI, 0.0-0.2, respectively) than patients with variant genotypes. However, no significant differences were found for the other three polymorphisms. After combining the risk genotypes of the five polymorphisms and using the high-risk group (2-5 risk genotypes) as the reference group, we found that the low-risk groups (0 or 1 risk genotype) had significantly lower recurrence risk among all patients (HR, 0.4, 95% CI, 0.3-0.6) and among HPV16-positive patients (HR, 0.2, 95% CI, 0.1-0.5). Our findings suggest that E2F2 polymorphisms may individually or jointly modify SCCOP recurrence risk, particularly for SCCOP patients with HPV16-positive tumors. © 2017 Wiley Periodicals, Inc.

Asiatic acid exerts anticancer potential in human ovarian cancer cells via suppression of PI3K/Akt/mTOR signalling

Context Asiatic acid, a triterpenoid compound extracted from the tropical medicinal plant Centella asiatica (Family: Apiaceae), has exhibited various biological activities. Objective This study was performed to investigate the cytotoxic effects of asiatic acid on human ovarian cancer cells. Materials and methods SKOV3 and OVCAR-3 ovarian cancer cells were exposed to different concentrations of asiatic acid (10-100 μg/mL) for 72 or 48 h. Cell viability, colony formation, cell cycle distribution, apoptotic response were examined. Involvement of the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway was tested. Results At the concentration of 40 μg/mL, asiatic acid caused about 50% reduction in the viability of ovarian cancer cells, but had little effect on the viability of normal human ovarian epithelial cells. Asiatic acid at 10 μg/mL reduced colony formation of ovarian cancer cells by 25-30%. Asiatic acid-treated cells showed a cell cycle arrest at the G0/G1 phase and 7- to 10-fold increase in apoptosis. The phosphorylation levels of PI3K, Akt and mTOR were remarkably lower in asiatic acid-treated cells. Overexpression of constitutively active Akt partially reversed the cytotoxic effects of asiatic acid, as evidenced by increased cell viability and colony formation. Furthermore, knockdown of Akt mimicked the growth-suppressive activity of asiatic acid. Discussion and conclusion These results provide first the evidence for the anticancer potential of asiatic acid in ovarian cancer cells, partially via inactivation of the PI3K/Akt/mTOR pathway. Asiatic acid may represent a potential therapeutic agent for ovarian cancer.

p14 expression differences in ovarian benign, borderline and malignant epithelial tumors

BACKGROUND

Abnormalities in tumor suppressors p14, p16 and p53 are reported in several human cancers. In ovarian epithelial carcinogenesis, p16 and p53 show higher immunohistochemical staining frequencies in malignant tumors and are associated with poor prognoses. p14 was only analyzed in carcinomas, with conflicting results. There are no reports on its expression in benign and borderline tumors. This study aims to determine p14, p16 and p53 expression frequencies in ovarian benign, borderline and malignant tumors and their associations with clinical parameters.

METHODS

A cross-sectional study utilizing immunohistochemistry was performed on paraffin-embedded ovarian epithelial tumor samples. Clinical data were collected from medical records. Fisher's exact test and the Bonferroni correction were performed for frequency associations. Survival comparisons utilized Kaplan-Meier and log rank testing. Associations were considered significant when p < 0.05.

RESULTS

p14 absent expression was associated with malignant tumors (60 % positive) (p = 0.000), while 93 % and 94 % of benign and borderline tumors, respectively, were positive. p16 was positive in 94.6 % of carcinomas, 75 % of borderline and 45.7 % of benign tumors (p = 0.000). p53 negative staining was associated with benign tumors (2.9 % positive) (p = 0.016) but no difference was observed between borderline (16.7 %) and malignant tumors (29.7 %) (p = 0.560). No associations were found between expression rates, disease-free survival times or clinical variables. Carcinoma subtypes showed no difference in expression.

CONCLUSIONS

This is the first description of p14 expression in benign and borderline tumors. It remains stable in benign and borderline tumors, while carcinomas show a significant absence of staining. This may indicate that p14 abnormalities occur later in carcinogenesis. p16 and p53 frequencies increase from benign to borderline and malignant tumors, similarly to previous reports, possibly reflecting the accumulation of inactive mutant protein. The small sample size may have prevented statistically significant survival analyses and clinical correlations. Future studies should investigate genetic abnormalities in p14 coding sequences and include all types of ovarian epithelial tumors. Bigger sample sizes may be needed for significant associations.

Follicle Depletion Provides a Permissive Environment for Ovarian Carcinogenesis

We modeled the etiology of postmenopausal biology on ovarian cancer risk using germ cell-deficient white-spotting variant (Wv) mice, incorporating oncogenic mutations. Ovarian cancer incidence is highest in peri- and postmenopausal women, and epidemiological studies have established the impact of reproductive factors on ovarian cancer risk. Menopause as a result of ovarian follicle depletion is thought to contribute to higher cancer risk. As a consequence of follicle depletion, female Wv mice develop ovarian tubular adenomas, a benign epithelial tumor corresponding to surface epithelial invaginations and papillomatosis frequently found in postmenopausal human ovaries. Lineage tracing using MISR2-Cre indicated that the tubular adenomas that developed in Wv mice were largely derived from the MISR2 lineage, which marked only a fraction of ovarian surface and oviduct epithelial cells in wild-type tissues. Deletion of p27, either heterozygous or homozygous, was able to convert the benign tubular adenomas into more proliferative tumors. Restricted deletion of p53 in Wv/Wv mice by either intrabursal injection of adenoviral Cre or inclusion of the MISR2-Cre transgene also resulted in augmented tumor growth. This finding suggests that follicle depletion provides a permissive ovarian environment for oncogenic transformation of epithelial cells, presenting a mechanism for the increased ovarian cancer risk in postmenopausal women.

Efficacy and Safety of Abemaciclib, an Inhibitor of CDK4 and CDK6, for Patients with Breast Cancer, Non-Small Cell Lung Cancer, and Other Solid Tumors

We evaluated the safety, pharmacokinetic profile, pharmacodynamic effects, and antitumor activity of abemaciclib, an orally bioavailable inhibitor of cyclin-dependent kinases (CDK) 4 and 6, in a multicenter study including phase I dose escalation followed by tumor-specific cohorts for breast cancer, non-small cell lung cancer (NSCLC), glioblastoma, melanoma, and colorectal cancer. A total of 225 patients were enrolled: 33 in dose escalation and 192 in tumor-specific cohorts. Dose-limiting toxicity was grade 3 fatigue. The maximum tolerated dose was 200 mg every 12 hours. The most common possibly related treatment-emergent adverse events involved fatigue and the gastrointestinal, renal, or hematopoietic systems. Plasma concentrations increased with dose, and pharmacodynamic effects were observed in proliferating keratinocytes and tumors. Radiographic responses were achieved in previously treated patients with breast cancer, NSCLC, and melanoma. For hormone receptor-positive breast cancer, the overall response rate was 31%; moreover, 61% of patients achieved either response or stable disease lasting ≥6 months.

SIGNIFICANCE

Abemaciclib represents the first selective inhibitor of CDK4 and CDK6 with a safety profile allowing continuous dosing to achieve sustained target inhibition. This first-in-human experience demonstrates single-agent activity for patients with advanced breast cancer, NSCLC, and other solid tumors. Cancer Discov; 6(7); 740-53. ©2016 AACR.See related commentary by Lim et al., p. 697This article is highlighted in the In This Issue feature, p. 681.

Differences in Clinical and Biological Features Between Type I and Type II Tumors in FIGO Stages I-II Epithelial Ovarian Carcinoma

OBJECTIVE

The objective of this study was to compare immunohistochemical profile for the apoptosis regulators p53, C-MYC, bax, PUMA, and PTEN and the cell cycle regulatory proteins p21 and p27, as well as clinical factors between types I and II tumors.

METHODS

In total, 131 patients in FIGO (International Federation of Gynecology and Obstetrics) stages I-II were divided into 2 groups of patients after type I tumors (n = 79) and type II tumors (n = 52). Differences in the immunohistochemical profile for the cell cycle-related proteins, detected by tissue microarrays and immune-histochemistry, were compared. For statistical tests, the Pearson χ test and the logistic regression model were used. All tests were 2-sided, and the level of statistical significance was P ≤ 0.05.

RESULTS

In multivariate logistic regression analysis with recurrent disease as endpoint, FIGO stage (odds ratio [OR], 4.7), type I/II tumors (OR, 3.8), body mass index (BMI) (OR, 3.5), and p53 status (OR, 4.2) all were found to be independent predictive factors. In 2 different multivariate logistic regression analyses with type I/II tumors as endpoint, both p53p21 (OR, 2.9) and p27 status (OR, 3.0) were associated with type II tumors. Differently, C-MYC status (OR, 0.4) was associated with type I tumors. Furthermore, age (OR, 1.04), BMI (OR, 0.4), and recurrent disease (OR, 4.3) all were associated to type II tumors. In survival analysis, there was a trend (P = 0.054) toward better disease-free survival for patients with type I tumors.

CONCLUSIONS

Concomitant positivity for p53 and negativity for p21, positivity for p27, and negativity for C-MYC in an epithelial ovarian tumor might strengthen the diagnostic option of type II tumor ovarian carcinoma. Patients with type II tumors were older, had lower BMI, and had more often recurrent disease than patients with type I tumors.

Expression and significance of CDC25B, PED/PEA-15 in esophageal carcinoma

OBJECTIVE

To explore the role of CDC25B, PED/PEA-15 in the development of esophageal carcinoma and its influence on the prognosis.

METHODS

Fluorescence quantitative real-time PCR and immunohistochemistry methods were used to analyze the expression of CDC25B, PED/PEA-15 in esophageal carcinoma. Moreover, survival analysis was done using the Kaplan-Meier method.

RESULTS

In 66 cases of esophageal cancer tissues, the relative content of CDC25B mRNA was 16.22 (13.93-18.90). The positive expression rate of CDC25B protein was 48.5%, significantly higher than normal mucosa tissues (0%) (p<0.01). The relative content of PED/PEA-15 mRNA was 12.47 (10.41-14.93). The positive expression rate of PED/PEA-15 protein was 68.2%, significantly higher than normal mucosa tissues (17.6%) (p<0.01). The CDC25B protein expression was correlated with differentiation grade and depth of invasion (p<0.05). The PED/PEA-15 protein expression was related to differentiation grade, lymph node metastasis, and depth of invasion (p<0.05). Survival analysis showed that the mean survival time of PED/PEA-15-positive expression group was lower compared with the negative expression group (χ(2)=5.549, p=0.018). Analysis of the relationship between CDC25B and PED/PEA-15 suggested that there was a positive correlation between them (r=4.061, p=0.044).

CONCLUSION

Both CDC25B and PED/PEA-15 play a certain role in the carcinogenesis of esophageal cancer, and PED/PEA-15 has a greater influence on postoperative survival time. They will be the new diagnostic/therapeutic targets in esophageal carcinoma.

Polymorphisms of cell cycle control genes influence the development of sporadic medullary thyroid carcinoma

BACKGROUND

The role of key cell cycle regulation genes such as, CDKN1B, CDKN2A, CDKN2B, and CDKN2C in sporadic medullary thyroid carcinoma (s-MTC) is still largely unknown.

METHODS

In order to evaluate the influence of inherited polymorphisms of these genes on the pathogenesis of s-MTC, we used TaqMan SNP genotyping to examine 45 s-MTC patients carefully matched with 98 controls.

RESULTS

A multivariate logistic regression analysis demonstrated that CDKN1B and CDKN2A genes were related to s-MTC susceptibility. The rs2066827*GT+GG CDKN1B genotype was more frequent in s-MTC patients (62.22%) than in controls (40.21%), increasing the susceptibility to s-MTC (OR=2.47; 95% CI=1.048-5.833; P=0.038). By contrast, the rs11515*CG+GG of CDKN2A gene was more frequent in the controls (32.65%) than in patients (15.56%), reducing the risk for s-MTC (OR=0.174; 95% CI=0.048-0.627; P=0.0075). A stepwise regression analysis indicated that two genotypes together could explain 11% of the total s-MTC risk. In addition, a relationship was found between disease progression and the presence of alterations in the CDKN1A (rs1801270), CDKN2C (rs12885), and CDKN2B (rs1063192) genes. WT rs1801270 CDKN1A patients presented extrathyroidal tumor extension more frequently (92%) than polymorphic CDKN1A rs1801270 patients (50%; P=0.0376). Patients with the WT CDKN2C gene (rs12885) presented larger tumors (2.9±1.8 cm) than polymorphic patients (1.5±0.7 cm; P=0.0324). On the other hand, patients with the polymorphic CDKN2B gene (rs1063192) presented distant metastases (36.3%; P=0.0261).

CONCLUSION

In summary, we demonstrated that CDKN1B and CDKN2A genes are associated with susceptibility, whereas the inherited genetic profile of CDKN1A, CDKN2B, and CDKN2C is associated with aggressive features of tumors. This study suggests that profiling cell cycle genes may help define the risk and characterize s-MTC aggressiveness.

MiR-506 suppresses proliferation and induces senescence by directly targeting the CDK4/6-FOXM1 axis in ovarian cancer

Ovarian carcinoma is the most lethal gynaecological malignancy. Better understanding of the molecular pathogenesis of this disease and effective targeted therapies are needed to improve patient outcomes. MicroRNAs play important roles in cancer progression and have the potential for use as either therapeutic agents or targets. Studies in other cancers have suggested that miR-506 has anti-tumour activity, but its function has yet to be elucidated. We found that deregulation of miR-506 in ovarian carcinoma promotes an aggressive phenotype. Ectopic over-expression of miR-506 in ovarian cancer cells was sufficient to inhibit proliferation and to promote senescence. We also demonstrated that CDK4 and CDK6 are direct targets of miR-506, and that miR-506 can inhibit CDK4/6-FOXM1 signalling, which is activated in the majority of serous ovarian carcinomas. This newly recognized miR-506-CDK4/6-FOXM1 axis provides further insight into the pathogenesis of ovarian carcinoma and identifies a potential novel therapeutic agent.

Genetic alteration and immunohistochemical staining patterns of ovarian high-grade serous adenocarcinoma with special emphasis on p53 immnnostaining pattern

We evaluated p53, KRAS, BRAF and CTNNB1 mutation and p53, WT1, p16 and beta-catenin expression in 31 ovarian high-grade serous adenocarcinoma. Twenty-five (80.6%) tumors contained functional mutations of p53; three frameshift, four nonsense and 19 missense mutations. None of the tumors showed KRAS, BRAF or CTNNB1 mutation. In all 18 tumors with missense mutations, ≥60% of tumor cells were strongly positive for p53 immunostaining whereas all tumors with frameshift or nonsense mutations were completely negative. Missense mutation was correlated with diffuse and strong imunoreaction and frameshift/nonsense mutation was correlated with completely negative immunoreaction (P = 0.000). Tumors with wild-type p53 revealed a wide range of immunostaining patterns. In 27 (87.1%) and 18 (58.1%) tumors, ≥50% of tumor cells were moderate to strongly positive for WT1 and p16, respectively. A considerable intratumoral heterogeneity for p16 expression was present. None of the tumors demonstrated nuclear beta-catenin expression. p53 mutations appear to be a powerful molecular marker for ovarian high-grade serous adenocarcinoma. Using p53 with an appropriate interpretation criteria together with WT1, p16 and beta-catenin, most of the high-grade serous adenocarcinoma could be distinguished from other ovarian tumors.

Glucosamine, a naturally occurring amino monosaccharide, inhibits A549 and H446 cell proliferation by blocking G1/S transition

Uncontrolled proliferation is important in tumorigenesis. In the present study, the effects of glucosamine on lung cancer cell proliferation were investigated. The expression of cyclin E, one of the key cyclins in the G1/S transition, and Skp2, the ubiquitin ligase subunit that targets the negative cell cycle regulator, p27Kip1, were also assessed. Moreover, the underlying mechanisms of action of glucosamine were investigated in lung cancer cells. A549 and H446 cells were synchronized using thymidine in the presence or absence of glucosamine. The effect of glucosamine on lung cancer cell proliferation was determined by MTT assay. Cyclin E and p27Kip1 proteins and their phosphorylation levels were detected by western blot analysis. Furthermore, the effect of glucosamine on the cell cycle was evaluated by flow cytometry. Glucosamine was found to inhibit lung cancer cell proliferation and to suppress Skp2 and cyclin E expression. Notably, the phosphorylation levels of cyclin E (Thr62) and p27Kip1 (Thr187) were downregulated by glucosamine, and negatively correlated with degradation. Glucosamine was also found to arrest lung cancer cells in the G1/S phase. Thus, glucosamine may inhibit lung cancer cell proliferation by blocking G1/S transition through the inhibition of cyclin E and Skp2 protein expression.

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.

Identification of genes and microRNAs involved in ovarian carcinogenesis

MicroRNAs (miRNAs) play roles in the clinic, both as diagnostic and therapeutic tools. The identification of relevant microRNAs is critically required for ovarian cancer because of the prevalence of late diagnosis and poor treatment options currently. To identify miRNAs involved in the development or progression of ovarian cancer, we analyzed gene expression profiles downloaded from Gene Expression Omnibus. Comparison of expression patterns between carcinomas and the corresponding normal ovarian tissues enabled us to identify 508 genes that were commonly up-regulated and 1331 genes that were down-regulated in the cancer specimens. Function annotation of these genes showed that most of the up-regulated genes were related to cell cycling, and most of the down-regulated genes were associated with the immune response. When these differentially expressed genes were mapped to MiRTarBase, we obtained a total of 18 key miRNAs which may play important regulatory roles in ovarian cancer. Investigation of these genes and microRNAs should help to disclose the molecular mechanisms of ovarian carcinogenesis and facilitate development of new approaches to therapeutic intervention.

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.

Optimizing molecular-targeted therapies in ovarian cancer: the renewed surge of interest in ovarian cancer biomarkers and cell signaling pathways

The hallmarks of ovarian cancer encompass the development of resistance, disease recurrence and poor prognosis. Ovarian cancer cells express gene signatures which pose significant challenges for cancer drug development, therapeutics, prevention and management. Despite enhancements in contemporary tumor debulking surgery, tentative combination regimens and abdominal radiation which can achieve beneficial response rates, the majority of ovarian cancer patients not only experience adverse effects, but also eventually relapse. Therefore, additional therapeutic possibilities need to be explored to minimize adverse events and prolong progression-free and overall response rates in ovarian cancer patients. Currently, a revival in cancer drug discovery is devoted to identifying diagnostic and prognostic ovarian cancer biomarkers. However, the sensitivity and reliability of such biomarkers may be complicated by mutations in the BRCA1 or BRCA2 genes, diverse genetic risk factors, unidentified initiation and progression elements, molecular tumor heterogeneity and disease staging. There is thus a dire need to expand existing ovarian cancer therapies with broad-spectrum and individualized molecular targeted approaches. The aim of this review is to profile recent developments in our understanding of the interrelationships among selected ovarian tumor biomarkers, heterogeneous expression signatures and related molecular signal transduction pathways, and their translation into more efficacious targeted treatment rationales.

Under-expression of the opioid growth factor receptor promotes progression of human ovarian cancer

The opioid growth factor (OGF) and its receptor, OGFr, serve as a tonically active inhibitory axis regulating the proliferation of human ovarian cancer cells. In the present study, we have investigated the repercussion on the progression of this deadly neoplasia when cells are engineered to molecularly under-express OGFr. shRNA constructs were used to knockdown OGFr in SKOV-3 cells; two clonal cell lines were examined. OGFr protein expression was decreased up to 73% in clones compared with wild-type (WT) and empty vector (EV) controls. OGFr-binding assays of clones revealed 50–55% decreases in binding capacity compared with control cells; binding affinity was comparable in all groups. Cell number in clones was increased 33–132%, and doubling times decreased 29–35%, compared with WT and EV cultures. Addition of exogenous OGF or naltrexone did not affect cell number in cultures with silenced OGFr. DNA synthesis of clonal cell lines was increased 136–146% from the WT and EV groups; no changes were noted in cell survival. Nude mice injected subcutaneously with cells under-expressing OGFr had an increased tumor incidence, decreased latency to tumor formation, increased tumor volume and decreased OGFr expression in tumors compared with WT and EV controls. OGF treatment in mice with WT or EV tumors, but not OGFr under-expressing tumors, inhibited tumor volume and weight. Collectively, these data demonstrate the critical nature of the OGF–OGFr axis as a determinant of the progression of human ovarian cancer, and suggest that attenuation of this system has an important bearing on the survival of these patients.

Functional polymorphisms of the hOGG1 gene confer risk to type 2 epithelial ovarian cancer in Chinese

OBJECTIVE

8-Hydroxydeoxyguanosine (8-OHdG) is an oxidized nucleoside that can lead to misincorporation of bases. Human 8-oxoguanine DNA glycosylase (hOGG1) is the key defense enzyme against mutation by the cellular 8-OHdG in duplex DNA. The present study was aimed to explore whether the hOGG1 gene variants play an important role in the carcinogenesis of epithelial ovarian cancer (EOC).

METHODS

Germ line variants in 5'-untranslated region (c.-18G>T, c.-23A>G, c.-45G>A, and c.-53G>C) and c.977C>G (Ser326Cys) polymorphism in exon7 of the hOGG1 gene in 420 sporadic EOCs and 840 controls were detected. Immunohistochemical and promoter luciferase activity assays were used to explore the effect of c.-18G>T variant on hOGG1 expression.

RESULTS

In contrast to type I EOC cases, patients with type II EOC were usually older, already in the advanced stage, and exhibited a common protein 53 (p53) overexpression. The frequencies of genotypes c.-18G/T and c.977G/G in hOGG1 were significantly high in the patients with type II EOC (odds ratio, 2.83; 95% confidence interval, 1.45-5.52; odds ratio, 1.66; 95% confidence interval, 1.26-2.17) but not in the patients with type I EOC. The average level of hOGG1 protein in the normal tissues adjacent to the type II EOC-carried c.-18G/T was lower than that with c.-18G/G (P = 0.01). The luciferase activity in the c.-18T allele was lower than that in the c.-18G allele (P = 0.001).

CONCLUSION

The genotypes of c.-18G/T in 5'-untranslated region and c.977G/G in exon7 of the hOGG1 gene would confer risk to type II EOC.

Association of genetic polymorphisms in cell-cycle control genes and susceptibility to endometrial cancer among Chinese women

Although genetic variations in cell-cycle control genes have been previously linked to cancer risk, no study has specifically evaluated the role of these gene variants in endometrial carcinogenesis. Using data from the Shanghai Endometrial Cancer Study, a population-based case-control study with 1,199 cases and 1,212 age-matched controls (1997-2003), the authors carried out a systematic evaluation of the association of cell-cycle control genes with endometrial cancer risk. Sixty-five tagging or potentially functional single nucleotide polymorphisms in the CCNB1, CCND1, CCNE1, CDK2, CDK4, CDK6, CDKN1A, CDKN1B, and CDKN2A genes were genotyped and evaluated. Three single nucleotide polymorphisms in the CDKN1B gene (rs11055027, rs3759216, and rs34330) were related to endometrial cancer risk, although only the association with rs34330 remained statistically significant after adjustment for multiple comparisons. The odds ratios for rs34330 were 1.33 (95% confidence interval (CI): 1.06, 1.66) and 1.51 (95% CI: 1.16, 1.94) for the CT and TT genotypes, respectively, compared with the CC genotype. In vitro luciferase reporter assays showed that the minor allele (A) in rs3759216, which was associated with decreased endometrial cancer risk (odds ratio = 0.73, 95% CI: 0.56, 0.94) without adjustment for multiple comparisons, significantly increased promoter activity. These findings suggest that polymorphisms of the CDKN1B gene may play a role in endometrial carcinogenesis.

The opioid growth factor (OGF) and low dose naltrexone (LDN) suppress human ovarian cancer progression in mice

OBJECTIVE

The opioid growth factor (OGF) and its receptor, OGFr, serve as a tonically active inhibitory axis regulating cell proliferation in normal cells and a variety of cancers, including human ovarian cancer. Blockade of OGF and OGFr with the nonselective opioid receptor antagonist naltrexone (NTX) upregulates expression of OGF and OGFr. Administration of a low dosage of NTX (LDN) blocks endogenous opioids from opioid receptors for a short period of time (4-6 h) each day, providing a window of 18-20 h for the upregulated opioids and receptors to interact. The present study investigated the repercussions of upregulating the OGF-OGFr axis by treatment with OGF or LDN on human ovarian tumorigenesis in vivo.

METHODS

Female nude mice were transplanted intraperitoneally with SKOV-3 human ovarian cancer cells and treated on a daily basis with OGF (10 mg/kg), LDN (0.1 mg/kg), or an equivalent volume of vehicle (saline). Tumor burden, as well as DNA synthesis, apoptosis, and angiogenesis was assessed in tumor tissue following 40 days of treatment.

RESULTS

OGF and LDN markedly reduced ovarian tumor burden (tumor nodule number and weight). The mechanism of action was targeted to an inhibition of tumor cell proliferation and angiogenesis; no changes in cell survival were noted.

CONCLUSIONS

This study shows that a native opioid pathway can suppress human ovarian cancer in a xenograft model, and provides novel non-toxic therapies for the treatment of this lethal neoplasia.

OVCA1 inhibits the proliferation of epithelial ovarian cancer cells by decreasing cyclin D1 and increasing p16

OVCA1, a tumor suppressor gene, is deleted or lower expressed in about 80% of ovarian cancer. Over expression of OVCA1 in human ovarian cancer A2780 cells inhibits cell proliferation and arrests cells in G1 stage. However, the fact that the molecular mechanism of OVCA1 inhibits cell growth is presently elusive. Here we investigated the potential signaling pathway induced by over-expression of OVCA1. Our results show that over-expression of human OVCA1 in ovarian cancer cells A2780 leads to down-regulation of cyclin D1, and up-regulation of p16, but no effect on the expression of NF-κB. It indicates that OVCA1 could inhibit the proliferation of ovarian cancer cell A2780 by p16/cyclin D1 pathway, but not by NF-κB.

Loss of p16INK4A expression in low-grade ovarian serous carcinomas

According to a tumor progression model, low-grade ovarian serous carcinomas may evolve from serous borderline tumors or micropapillary tumors. We sought to investigate the role of and associations between BRAF mutational status, extracellular signal regulated kinase activation, and p16(INK4A) expression in various types of ovarian serous tumors. We analyzed 29 typical ovarian serous borderline tumors, 8 micropapillary tumors, 4 low-grade invasive ovarian serous carcinomas, and 24 high-grade invasive ovarian serous carcinomas for the BRAF mutational status at codon 600; in addition, expression levels of the downstream signaling protein extracellular signal regulated kinase and the p16(INK4A) tumor suppressor protein were assessed by immunohistochemistry. There was a decline in p16(INK4A) expression from serous borderline tumors to micropapillary tumors with almost complete loss in low-grade invasive carcinomas. High-grade carcinomas had a variable p16(INK4A) expression pattern. We found a T1799A BRAF mutation in 12 typical serous borderline tumors (41%) and 1 micropapillary tumor (12.5%). No mutations were found in the low-grade and high-grade invasive carcinomas (0%). Among the typical borderline tumors, cases with BRAF mutations tended to have stronger p16(INK4A) expression compared with cases with wild-type BRAF. No other correlations were identified between the BRAF mutational status and expression levels of the analyzed proteins. Loss of p16(INK4A) expression may be a pathogenetic factor in the progression from serous borderline tumors to low-grade invasive carcinomas. The divergent molecular profiles support the theory that high-grade carcinomas are unrelated to serous borderline tumors or low-grade carcinomas.

Prognostic impact of p53, p27, and C-MYC on clinicopathological features and outcome in early-stage (FIGO I-II) epithelial ovarian cancer

INTRODUCTION

The objective of the study was to evaluate the prognostic effect of p53, p27, and C-MYC on clinicopathological features, recurrent disease, and disease-free survival (DFS) of 131 patients with ovarian cancer in International Federation of Gynecology and Obstetrics (FIGO) stages I-II.

METHODS

The technique of tissue microarray and immunohistochemistry was used for detection of positivity/overexpression of the biological markers p53, p27, and C-MYC.

RESULTS

In the complete series, the 5-year and overall survival rates were 68% and 71%, respectively. Positive staining for p53, p27, and C-MYC was detected in 25%, 57%, and 76% of cases, respectively. Positivity of p53, p27, concomitant p53-p27, C-MYC, and C-MYC-p27 status were associated with tumor grade. Positivity of p27 and concomitant p53-p27 were related to serous tumors. In survival analysis, DFS was related to p53, combined p53-p27, and combined p53-C-MYC status. Significant predictive factors for tumor recurrences were the FIGO stage (odds ratio [OR] = 9.8), status of node sampling (OR = 0.2), and p53 status (OR = 3.7) in a logistic regression analysis. In a multivariate Cox regression analysis, FIGO stage (hazard ratio [HR] = 4.3) and p53 status (HR = 3.0) were significant prognostic factors for DFS. In a separate Cox regression analysis, FIGO stage (HR = 2.0) and concomitant p53-p27-C-MYC status (HR = 0.3) were independent prognostic factors for DFS. It was possible to identify a subgroup, constituting 30% of the patients, who had excellent survival with tumors of concomitant p53 negativity, p27 positivity, and C-MYC positivity apart from the clinicopathological factors. Patients in this subgroup were longtime survivors with DFS of 92% at 5 and 9 years.

CONCLUSIONS

The results of this study strongly suggest that patients with p53-positive tumors (alone/or combined with p27 and/or C-MYC) had significantly worse survival (DFS) compared with patients with p53-negative tumors. Patients with p53-positive tumors continued to have recurrences after the 5-year follow-up and die in disease.

Cyclin D1 predicts the prognosis of advanced serous ovarian cancer

We previously reported that cyclin E (CCNE1) amplification is strongly associated with resistance to treatment in serous ovarian cancer by high-resolution oligonucleotide copy number analysis. Dysregulation of cell cycle control has been implicated as the key event in human oncogenesis, and aberrant expression of G1-S phase-related genes in particular has been reported in epithelial ovarian cancer (EOC). Nevertheless, there are conflicting results concerning the prognostic values of these abnormalities in EOC. This study focused on advanced serous EOC cases and investigated the association between the expression of G1-S phase-regulatory proteins and clinicopathological parameters. The utility of these proteins as prognostic factors was assessed, and whether these targets reflect chemoresistance of advanced serous EOC was investigated. A total of 66 patients treated by primary surgery were evaluated in this study. Immunohistochemical analysis for cyclin D1, pRb, p16, p53, p27(Kip1), p21(Waf1/Cip1) and cyclin E was performed on formalin-fixed tissue sections collected from primary surgical specimens. The correlations between the expression of these proteins and the clinicopathological parameters, including progression-free survival (PFS), overall survival (OS) and chemosensitivity, were examined. Upon univariate analysis, overexpression of cyclin D1 was positively correlated with reduced PFS (p=0.00062) and OS (p=0.00037). Reduced expression of p27(Kip1) was associated with shorter OS (p=0.064). Upon multivariate analysis, overexpression of cyclin D1 (p=0.0019), reduced expression of p27(Kip1) (p=0.042) and residual tumor volume (p=0.0092) were identified as independent predictors of OS. Overexpression of cyclin D1 (p=0.011) as well as residual tumor volume (p=0.006) were significantly associated with first-line chemosensitivity. In advanced serous EOC, overexpression of cyclin D1 contributed largely to poor prognosis, and this may have been in part mediated by chemoresistance. Cyclin D1 is a possible target for overcoming the refractory nature of advanced serous EOC.

Genomic expression profiles in liver of mice exposed to purified terephthalic acid manufacturing wastewater

DNA micorarray was used to analyze hepatic transcriptional profile of male mice (Mus musculus) after 35-d intragastric perfusion treatment with purified terephthalic acid (PTA) manufacturing wastewater. Haematological analysis demonstrated that the levels of glutamyl transferase and lactate dehydrogenase in serum were significantly decreased, and DNA microarray showed that a total of 306 genes were differentially expressed in PTA wastewater-treated mice. According to Kyoto encyclopedia of genes and genomes pathway database, the differentially expressed genes were mainly grouped to metabolic pathways (58 genes) and biological processes (101 genes). PTA wastewater had significant impacts upon metabolisms of lipid, carbohydrate, amino acid, vitamin and nucleotide. Several signal transduction pathways are most susceptible to PTA wastewater, including mitogen-activated protein kinases, Janus kinase/signal transducers and activators of transcription and calcium signaling pathways. Potential public health problems may arise from the discharge of PTA wastewater into the environment.

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.

Identification of glucocorticoid-induced leucine zipper as a key regulator of tumor cell proliferation in epithelial ovarian cancer

Background

Little is known about the molecules that contribute to tumor progression of epithelial ovarian cancer (EOC), currently a leading cause of mortality from gynecological malignancies. Glucocorticoid-Induced Leucine Zipper (GILZ), an intracellular protein widely expressed in immune tissues, has been reported in epithelial tissues and controls some of key signaling pathways involved in tumorigenesis. However, there has been no report on GILZ in EOC up to now. The objectives of the current study were to examine the expression of GILZ in EOC and its effect on tumor cell proliferation.

Results

GILZ expression was measured by immunohistochemical staining in tissue sections from 3 normal ovaries, 7 benign EOC and 50 invasive EOC. GILZ was not detected on the surface epithelium of normal ovaries and benign tumors. In contrast, it was expressed in the cytoplasm of tumor cells in 80% EOC specimens. GILZ immunostaining scores correlated positively to the proliferation marker Ki-67 (Spearman test in univariate analysis, P < 0.00001, r = 0.56). They were also higher in tumor cells containing large amounts of phosphorylated protein kinase B (p-AKT) (unpaired t test, P < 0.0001). To assess the effect of GILZ on proliferation and AKT activation, we used the BG-1 cell line derived from ovarian tumor cells as a cellular model. GILZ expression was either enhanced by stable transfection or decreased by the use of small interfering (si) RNA targeting GILZ. We found that GILZ increased cell proliferation, phospho-AKT cellular content and AKT kinase activity. Further, GILZ upregulated cyclin D1 and phosphorylated retinoblastoma (p-Rb), downregulated cyclin-dependent kinase inhibitor p21, and promoted the entry into S phase of cell cycle.

Conclusion

The present study is the first to identify GILZ as a molecule produced by ovarian cancer cells that promotes cell cycle progression and proliferation. Our findings clearly indicate that GILZ activates AKT, a crucial signaling molecule in tumorigenesis. GILZ thus appears as a potential key molecule in EOC.

Cell cycle genes and ovarian cancer susceptibility: a tagSNP analysis

Background:

Dysregulation of the cell cycle is a hallmark of many cancers including ovarian cancer, a leading cause of gynaecologic cancer mortality worldwide.

Methods:

We examined single nucleotide polymorphisms (SNPs) (n=288) from 39 cell cycle regulation genes, including cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors, in a two-stage study. White, non-Hispanic cases (n=829) and ovarian cancer-free controls (n=941) were genotyped using an Illumina assay.

Results:

Eleven variants in nine genes (ABL1, CCNB2, CDKN1A, CCND3, E2F2, CDK2, E2F3, CDC2, and CDK7) were associated with risk of ovarian cancer in at least one genetic model. Seven SNPs were then assessed in four additional studies with 1689 cases and 3398 controls. Association between risk of ovarian cancer and ABL1 rs2855192 found in the original population [odds ratio, OR_{BB vs AA} 2.81 (1.29–6.09), P=0.01] was also observed in a replication population, and the association remained suggestive in the combined analysis [OR_{BB vs AA} 1.59 (1.08–2.34), P=0.02]. No other SNP associations remained suggestive in the replication populations.

Conclusion:

ABL1 has been implicated in multiple processes including cell division, cell adhesion and cellular stress response. These results suggest that characterization of the function of genetic variation in this gene in other ovarian cancer populations is warranted.

Opioid growth factor-opioid growth factor receptor axis is a physiological determinant of cell proliferation in diverse human cancers

The opioid growth factor (OGF) regulates cell proliferation of human cancer cells through the cyclin-dependent kinase inhibitory pathway, with mediation of this action by the OGF receptor (OGFr). The ubiquity of the OGF-OGFr axis in human cancer is unknown. We used 31 human cancer cell lines, representative of more than 90% of neoplasias occurring in humans, and found that OGF and OGFr were detected in the cytoplasm and nucleus by immunohistochemistry. The addition of OGF to cultures depressed cell number up to 41%, whereas naltrexone (NTX) increased cell proliferation by up to 44%, a total of 85% in the modulating capacity for the OGF-OGFr axis. Neutralization of OGF by specific antibodies led to a marked increase in cell number. Knockdown of OGFr by OGFr-siRNA resulted in a significant increase in the number of cells, even in the face of the addition of exogenous OGF. The cultures to which NTX was added and subjected to OGFr-siRNA were similar to those with OGF-siRNA alone. The OGF-OGFr axis, a physiological determinant of cell-proliferative activity, is a ubiquitous feature of human cancer cells. The identification of this native biological system in neoplasia may be important in understanding the pathophysiology of neoplasia, and in designing treatment modalities that utilize the body's own chemistry.

Implications of endoplasmic reticulum stress, the unfolded protein response and apoptosis for molecular cancer therapy. Part II: targeting cell cycle events, caspases, NF-κB and the proteasome

BACKGROUND

Endoplasmic reticulum stress (ERS), the unfolded protein response (UPR) and apoptosis signal transduction pathways are fundamental to normal cellular homeostasis and survival, but are exploited by cancer cells to promote the cancer phenotype.

OBJECTIVE

Collateral activation of ERS and UPR role players impact on cell growth, cell cycle arrest or apoptosis, genomic stability, tumour initiation and progression, tumour aggressiveness and drug resistance. An understanding of these processes affords promising prospects for specific cancer drug targeting of the ERS, UPR and apoptotic pathways.

METHOD

This review (Part II of II) brings forward the latest developments relevant to the molecular connections among cell cycle regulators, caspases, NF-κB, and the proteasome with ERS and UPR signalling cascades, their functions in apoptosis induction, apoptosis resistance and oncogenesis, and how these relationships can be exploited for targeted cancer therapy.

CONCLUSION

Overall, ERS, the UPR and apoptosis signalling cascades (the molecular therapeutic targets) and the development of drugs that attack these targets signify a success story in cancer drug discovery, but a more reductionist approach is necessary to determine the precise molecular switches that turn on antiapoptotic and pro-apoptotic programmes.

Implications of endoplasmic reticulum stress, the unfolded protein response and apoptosis for molecular cancer therapy. Part I: targeting p53, Mdm2, GADD153/CHOP, GRP78/BiP and heat shock proteins

BACKGROUND

In eukaryotes, endoplasmic reticulum stress (ERS) and the unfolded protein response (UPR) are coordinately regulated to maintain steady-state levels and activities of various cellular proteins to ensure cell survival.

OBJECTIVE

This review (Part I of II) focuses on specific ERS and UPR signalling regulators, their expression in the cancer phenotype and apoptosis, and proposes how their implication in these processes can be rationalised into proteasome inhibition, apoptosis induction and the development of more efficacious targeted molecular cancer therapies.

METHOD

In this review, we contextualise many ERS and UPR client proteins that are deregulated or mutated in cancers and show links between ERS and the UPR, their implication in oncogenic transformation, tumour progression and escape from immune surveillance, apoptosis inhibition, angiogenesis, metastasis, acquired drug resistance and poor cancer prognosis.

CONCLUSION

Evasion of programmed cell death or apoptosis is a hallmark of cancer that enables tumour cells to proliferate uncontrollably. Successful eradication of cancer cells through targeting ERS- and UPR-associated proteins to induce apoptosis is currently being pursued as a central tenet of anticancer drug discovery.

Candidate gene analysis using imputed genotypes: cell cycle single-nucleotide polymorphisms and ovarian cancer risk

Polymorphisms in genes critical to cell cycle control are outstanding candidates for association with ovarian cancer risk; numerous genes have been interrogated by multiple research groups using differing tagging single-nucleotide polymorphism (SNP) sets. To maximize information gleaned from existing genotype data, we conducted a combined analysis of five independent studies of invasive epithelial ovarian cancer. Up to 2,120 cases and 3,382 controls were genotyped in the course of two collaborations at a variety of SNPs in 11 cell cycle genes (CDKN2C, CDKN1A, CCND3, CCND1, CCND2, CDKN1B, CDK2, CDK4, RB1, CDKN2D, and CCNE1) and one gene region (CDKN2A-CDKN2B). Because of the semi-overlapping nature of the 123 assayed tagging SNPs, we performed multiple imputation based on fastPHASE using data from White non-Hispanic study participants and participants in the international HapMap Consortium and National Institute of Environmental Health Sciences SNPs Program. Logistic regression assuming a log-additive model was done on combined and imputed data. We observed strengthened signals in imputation-based analyses at several SNPs, particularly CDKN2A-CDKN2B rs3731239; CCND1 rs602652, rs3212879, rs649392, and rs3212891; CDK2 rs2069391, rs2069414, and rs17528736; and CCNE1 rs3218036. These results exemplify the utility of imputation in candidate gene studies and lend evidence to a role of cell cycle genes in ovarian cancer etiology, suggest a reduced set of SNPs to target in additional cases and controls.

Role of genetic polymorphisms and ovarian cancer susceptibility

The value of identifying women with an inherited predisposition to epithelial ovarian cancer has become readily apparent with the identification of the BRCA1, and BRCA2 genes. Women who inherit a deleterious mutation in either of these genes have a very high lifetime risk of ovarian cancer (10-60%) and to some extent, increased risks of fallopian tube and peritoneal cancer. These highly lethal cancers are almost completely prevented by prophylactic salpingoophorectomy. BRCA1/2 mutation testing has become the accepted standard of care in families with a strong history of breast and/or ovarian cancer. This approach has the potential to reduce ovarian cancer mortality by about 10%. Although the ability to perform genetic testing for BRCA1 and 2 represents a significant clinical advance, the frequency of mutations in these high penetrance ovarian cancer susceptibility genes is low in most populations. There is evidence to suggest that ovarian cancer susceptibility might be affected by common low penetrance genetic polymorphisms like it was shown for several common disorders like diabetes or breast cancer. Although such polymorphisms would increase risk to a lesser degree, they could contribute to the development of a greater proportion of ovarian cancers by virtue of their higher frequencies in the population. It has been shown that the most powerful approach to studying low penetrance genes is an association study rather than a linkage study design. This review describes the efforts that have been made in this field by individual case-control studies and through multi-center collaborations as part of international consortia such as the Ovarian Cancer Association Consortium (OCAC).