Mitogen-activated protein kinases in normal and (pre)neoplastic ovarian surface epithelium

Aberrant miR-3135b and miR-1273g-3p expression in the peripheral blood samples of BRCA1/2 (±) ovarian cancer patients

Ovarian cancer (OC) ranks as the eighth most prevalent malignancy among women globally. The short non-coding RNA molecules, microRNAs (miRNAs) target multiple mRNAs and regulate the gene expression. Here in this study, we aimed to validate miR-3135b and miR-1273g-3p as novel biomarkers for prognostic and diagnostic factor OC. After RNA isolation, we analyzed the miR-3135b and miR-1273g-3p expression in peripheral blood samples derived from 150 OC patients. Subsequently, we compared their expression levels with 100 healthy controls. The differences of miR-3135b and miR-1273g-3p expression were detected using the Quantitative Real Time-PCR (qRT-PCR) technique following miRNA-specific cDNA synthesis pursing miRNA separation. The miR-3135b and miR-1273g-3p were higher in OC patients who tested positive for BRCA1/2 compared to BRCA-negative patients, and healthy cases. The level of miR-3135b demonstrated a roughly 4.82-fold increase in OC patients in comparison to the healthy cases, while miR-1273g-3p expression exhibited a roughly 6.77-fold increase. The receiver operating characteristic (ROC) analysis has demonstrated the potential of miR-3135b and miR-1273g-3p as markers for distinguishing between OC patients and healthy controls. The higher expressions of miR-3135b and miR-1273g-3p could be associated with OC development. Moreover, miR-3135b may have a diagnostic potential and miR-1273g-3p may have both diagnostic and prognostic potential in OC cell differentiation. The string analysis has revealed an association between miR-1273g-3p and the MDM2 gene, suggesting a potential link to tumor formation through the proteasomal degradation of the TP53 tumor suppressor gene. Additionally, the analysis indicates an association of miR-1273g-3p with CHEK1, a gene involved in checkpoint-mediated cell cycle arrest. String analysis also indicates that miR-3135b is associated with the MAPK1 gene, causing activation of the oncogenesis cascade. In conclusion, miR-1273g-3p, and miR-3135b exhibit significant potential as diagnostic markers. However, further research is needed to comprehensively investigate these miRNAs diagnostic and predictive characteristics in a larger cohort.

Prognostic and immune correlation analysis of mitochondrial autophagy and aging-related genes in lung adenocarcinoma

PURPOSE

Mitophagy and aging (MiAg) are very important pathophysiological mechanisms contributing to tumorigenesis. MiAg-related genes have prognostic value in lung adenocarcinoma (LUAD). However, prognostic, and immune correlation studies of MiAg-related genes in LUAD are lacking.

METHODS

MiAg differentially expressed genes (DEGs) in LUAD were obtained from public sequencing datasets. A prognostic model including MiAg DEGs was constructed according to patients divided into low- and high-risk groups. Gene Ontology, gene set enrichment analysis, gene set variation analysis, CIBERSORT immune infiltration analysis, and clinical characteristic correlation analyses were performed for functional annotation and correlation of MiAgs with prognosis in patients with LUAD.

RESULTS

Seven MiAg DEGs of LUAD were identified: CAV1, DSG2, DSP, MYH11, NME1, PAICS, PLOD2, and the expression levels of these genes were significantly correlated (P < 0.05). The RiskScore of the MiAg DEG prognostic model demonstrated high predictive ability of overall survival of patients diagnosed with LUAD. Patients with high and low MiAg phenotypic scores exhibited significant differences in the infiltration levels of eight types of immune cells (P < 0.05). The multi-factor DEG regression model showed higher efficacy in predicting 5-year survival than 3- and 1-year survival of patients with LUAD.

CONCLUSIONS

Seven MiAg-related genes were identified to be significantly associated with the prognosis of patients diagnosed with LUAD. Moreover, the identified MiAg DEGs might affect the immunotherapy strategy of patients with LUAD.

Glycosphingolipids are mediators of cancer plasticity through independent signaling pathways

The molecular repertoire promoting cancer cell plasticity is not fully elucidated. Here, we propose that glycosphingolipids (GSLs), specifically the globo and ganglio series, correlate and promote the transition between epithelial and mesenchymal cells. The epithelial character of ovarian cancer remains stable throughout disease progression, and spatial glycosphingolipidomics reveals elevated globosides in the tumor compartment compared with the ganglioside-rich stroma. CRISPR-Cas9 knockin mediated truncation of endogenous E-cadherin induces epithelial-to-mesenchymal transition (EMT) and decreases globosides. The transcriptomics analysis identifies the ganglioside-synthesizing enzyme ST8SIA1 to be consistently elevated in mesenchymal-like samples, predicting poor outcome. Subsequent deletion of ST8SIA1 induces epithelial cell features through mTOR^S2448 phosphorylation, whereas loss of globosides in ΔA4GALT cells, resulting in EMT, is accompanied by increased ERK^Y202/T204 and AKT^S124. The GSL composition dynamics corroborate cancer cell plasticity, and further evidence suggests that mesenchymal cells are maintained through ganglioside-dependent, calcium-mediated mechanisms.

Applications of Proteomics in Ovarian Cancer: Dawn of a New Era

The ability to identify ovarian cancer (OC) at its earliest stages remains a challenge. The patients present an advanced stage at diagnosis. This heterogeneous disease has distinguishable etiology and molecular biology. Next-generation sequencing changed clinical diagnostic testing, allowing assessment of multiple genes, simultaneously, in a faster and cheaper manner than sequential single gene analysis. Technologies of proteomics, such as mass spectrometry (MS) and protein array analysis, have advanced the dissection of the underlying molecular signaling events and the proteomic characterization of OC. Proteomics analysis of OC, as well as their adaptive responses to therapy, can uncover new therapeutic choices, which can reduce the emergence of drug resistance and potentially improve patient outcomes. There is an urgent need to better understand how the genomic and epigenomic heterogeneity intrinsic to OC is reflected at the protein level, and how this information could potentially lead to prolonged survival.

Arctigenin attenuates paraquat-induced human lung epithelial A549 cell injury by suppressing ROS/p38 mitogen-activated protein kinases-mediated apoptosis

BACKGROUND

Paraquat (PQ)-induced acute lung injury (ALI) and pulmonary fibrosis are common diseases with high mortality but without effective antidotes in emergency medicine. Our previous study has proved that arctigenin suppressed pulmonary fibrosis induced by PQ. We wondered whether arctigenin could also have a protective effect on PQ-induced ALI.

METHODS

A PQ-induced A549 cell injury model was used, and the effect of arctigenin was determined by a cell counting kit-8 (CCK-8) cell viability assay. In addition, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) staining assays and mitochondrial membrane potential assays were performed to evaluate the level of cell apoptosis. The generation of reactive oxygen species (ROS) was reflected by dihydroethidium (DHE) staining and a 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay. Moreover, immunoblotting studies were used to assess the expression of mitogen-activated protein kinases (MAPKs) and p38 MAPK.

RESULTS

Arctigenin attenuated PQ-induced inhibition of A549 cell viability in a dose-dependent manner. Arctigenin also significantly reduced PQ-induced A549 cell apoptosis, as reflected by the TUNEL assay and mitochondrial membrane potential assay, which may result from suppressed ROS/p38 MAPK signaling because we found that arctigenin dramatically suppressed ROS generation and p38 MAPK phosphorylation.

CONCLUSION

Arctigenin could attenuate PQ-induced lung epithelial A549 cell injury in vitro by suppressing ROS/p38 MAPK-mediated cell apoptosis, and arctigenin might be considered a potential candidate drug for PQ-induced ALI.

Current and Futuristic Roadmap of Ovarian Cancer Management: An Overview

Ovarian cancer (OC) is the most lethal gynecological malignancy among women worldwide. In most cases, it is diagnosed late at an advanced stage and does not respond well to existing therapies leading to its poor prognosis. In addition, other factors including epidemiological, complex histological diversity, multiple molecular alterations, and overlapping signaling pathways are also important contributors to poor disease outcome. Efforts have continued to develop a deeper understanding of the molecular pathogenesis and altered signaling nodes that provide hope for better clinical management through the development of novel approaches for early diagnosis, disease subtyping, prognosis, and therapy. In this chapter, we provide a detailed overview of OC and its histological subtypes and discuss prevalent molecular aberrations and active signaling pathways that drive OC progression. We also summarize various diagnostic and prognostic markers and therapeutic approaches currently being employed and discuss emerging findings that hold the potential to change the future course of OC management.

Upregulated Expression of Calcium-Dependent Annexin A6: A Potential Biomarker of Ovarian Carcinoma

PURPOSE

An early and accurate diagnosis of ovarian carcinoma (OC) may reduce morbidity and mortality of the patients. To improve the clinical outcome in OC patients, the present study is aimed at identifying robust biomarkers for early OC diagnosis. EXPERIMENTAL DESIGN: In order to look for early-stage protein markers, a systematic protein profiling approach involving 2-dimensional electrophoresis coupled with mass spectrometric analyses of human malignant and non-malignant ovarian biopsy samples, is performed.

RESULTS

Six 2D gel spots, corresponding to five proteins, display statistically significant differential expression in the tumor tissues compared to benign controls (FDR ≤ 0.05; PMF score ≥ 79). Ingenuity pathway analysis predicts two proteins, that is, Ca²⁺ -dependent membrane-binding protein annexin A6 (AnxA6) and the metabolic enzyme l-lactate dehydrogenase A chain, as potential predictive biomarkers. Increased expression of AnxA6 is further ascertained by Western blot and enzyme linked immunosorbent assay in the resected tissues and the plasma samples. The expression is found markedly increasing particularly in the advanced stage tumors.

CONCLUSIONS AND CLINICAL RELEVANCE

The significant upregulation of AnxA6 in OC, reported for the first time, is likely to provide insight into the mechanism of OC progression, which may lead to the design of potential diagnostic and therapeutic strategies.

LAMC2 regulated by microRNA-125a-5p accelerates the progression of ovarian cancer via activating p38 MAPK signalling

AIMS

Laminin γ2 (LAMC2) is over-expressed in ovarian cancer, and its high expression facilitates cell invasion. Nevertheless, the effects of LAMC2 on other ovarian cancer cell functions and its underlying mechanism remain largely unclear. Bioinformatics analysis shows that LAMC2 is a predicted target of miR-125a-5p and miR-193a-3p. Therefore, the present study aimed to investigate the effects of LAMC2 in ovarian cancer progression and determine whether LAMC2 expression is under the regulation of miR-125a-5p or miR-193a-3p in ovarian cancer.

MATERIALS AND METHODS

Immunohistochemistry staining, western blot and qPCR were used to detect LAMC2 expression profiles. CCK-8, flow cytometry and tumour formation assays were used to assess cell proliferation, apoptosis and tumorigenesis. The interaction between miR-125a-5p/miR-193a-3p and LAMC2 were determined by the luciferase gene reporter assay.

KEY FINDINGS

The results showed that LAMC2 was over-expressed in ovarian cancer tissues and cell lines. Over-expression of LAMC2 significantly promoted cell proliferation and repressed cell apoptosis, as well as increased the expression levels of p38, p-p38, c-myc and CREB, and translocated p38 protein to the nucleus. In addition, the promotion of cell proliferation and repression of cell apoptosis mediated by LAMC2 over-expression were all weakened when p38 was downregulated. Moreover, LAMC2 expression was negatively regulated by miR-125a-5p, which inhibited the nuclear accumulation of p38 protein. Upregulation of LAMC2 significantly abolished the effects of miR-125a-5p on cell proliferation inhibition and cell apoptosis promotion, as well as tumourigenesis repression.

SIGNIFICANCE

The present study clarified that LAMC2 functioned as an oncogene in ovarian cancer through upregulating p38 under the regulation of miR-125a-5p.

Dual Inhibitors-Loaded Nanotherapeutics that Target Kinase Signaling Pathways Synergize with Immune Checkpoint Inhibitor

Introduction

Immune checkpoint inhibitors that boost cytotoxic T cell-based immune responses have emerged as one of the most promising approaches in cancer treatment. However, it is increasingly being realized that T cell activation needs to be rationally combined with molecularly targeted therapeutics for a maximal anti-tumor outcome. Currently, two oncogenic drivers, MAPK and PI3K-mTOR have emerged as the two main molecular targets for combining with immunotherapy. However, there are major challenges in enabling such combinations: first, such combinations can result in high rates of toxicity. Second, while, these molecular targets could be driving tumor progression, they are essential for activation of the immune cells. So, the kinase inhibitors and immunotherapy can antagonize each other.

Objectives

We rationalized that the synergistic combination of kinase inhibitors and immunotherapy could be enabled by dual inhibitors-loaded supramolecular nanotherapeutics (DiLN) that can co-deliver PI3K- and MAPK-inhibitors to the cancer cells and activate immune response by T cell-modulating immunotherapy, resulting in greater anti-tumor efficacy while minimizing toxicity.

Methods

We engineered DiLNs by designing the amphiphilic building blocks (both drugs and co-lipids) that enables supramolecular nanoassembly. DiLNs were tested for their physiochemical properties including size, morphology, stability and drug release kinetics profiles. The efficacy of DiLNs was tested in drug-resistant cells such as BRAF^V600E melanoma (D4M), Clear cell ovarian carcinoma (TOV21G) cells. The tumor inhibition efficiency of DiLNs in combination with immune checkpoint inhibitor antibody was studied in syngeneic D4M animal model.

Results

DiLNs were stable for over a month and released the drugs in a sustained manner. In vitro cytotoxicity studies in D4M and TOV21G cells showed that DiLNs were significantly more effective than free drugs. In vivo studies showed that the combination of DiLNs with anti PD-L1 antibody resulted in superior antitumor effect and survival.

Conclusion

This study shows that the rational combination of DiLNs that target multiple oncogenic signaling pathways with immune checkpoint inhibitors could emerge as an effective strategy to improve immunotherapeutic response against drug resistant tumors.

Sideroxylin (Callistemon lanceolatus) suppressed cell proliferation and increased apoptosis in ovarian cancer cells accompanied by mitochondrial dysfunction, the generation of reactive oxygen species, and an increase of lipid peroxidation

Sideroxylin is a C-methylated flavone isolated from Callistemon lanceolatus and exerts antimicrobial activity against Staphylococcus aureus. However, the anticancer effects of sideroxylin and its intracellular signaling mechanisms have not yet been identified. Results of our study showed that sideroxylin decreased cell proliferation and increased apoptosis, causing DNA fragmentation, depolarization of the mitochondrial membrane, the generation of reactive oxygen species, and an increase of lipid peroxidation in ovarian cancer cells (ES2 and OV90 cells). Additionally, sideroxylin activated the phosphorylation of ERK1/2, JNK, P38, and MAPK proteins and the use of LY294002, U0126, SB203580, and SP600125 to block their phosphorylation, respectively, in ES2 and OV90 cells. Collectively, the results of present study indicated that sideroxylin was a novel therapeutic agent to combat the proliferation of ovarian cancer cells through the induction of mitochondrial dysfunction and the activation of PI3 K and MAPK signal transduction.

Effect of CXCR4 silencing with shRNA on MAPK signaling in ovarian cancer

Our previous study demonstrated that short hairpin RNA (shRNA) targeting of C-X-C chemokine receptor type 4 (CXCR4) significantly inhibited cell proliferation, metastasis and invasion. On the basis of these results, the aim of the present study was to determine the effects of shRNA-CXCR4 silencing on mitogen-activated protein kinase (MAPK) signaling in human SW626 ovarian cancer cells. Following silencing the CXCR4 gene with shRNA, the mRNA expression of apoptosis signal-regulating kinase 1 (ASK1) was determined using the reverse transcription-quantitative polymerase chain reaction, whereas the protein expression of extracellular-signal-regulated kinase (ERK)1/2 and phosphorylated (p)-c-Jun were determined using immunocytochemistry and western blotting. SW626 cells transfected with shRNA-CXCR4 exhibited significantly increased ASK1 mRNA expression (P<0.05), significantly increased p-c-Jun protein expression (P<0.05), and significantly decreased ERK1/2 protein expression (P<0.05). Silencing the CXCR4 gene with shRNA significantly inhibited cell proliferation, promoted cell apoptosis and may be mediated by the MAPK signaling pathway.

Chrysin attenuates progression of ovarian cancer cells by regulating signaling cascades and mitochondrial dysfunction

Chrysin is mainly found in passion flowers, honey, and propolis acts as a potential therapeutic and preventive agent to inhibit proliferation and invasion of various human cancer cells. Although chrysin has anti-carcinogenic effects in several cancers, little is known about its functional roles in ovarian cancer which shows poor prognosis and chemoresistance to traditional therapeutic agents. In the present study, we investigated functional roles of chrysin in progression of ovarian cancer cells using ES2 and OV90 (clear cell and serous carcinoma, respectively) cell lines. Results of the current study demonstrated that chrysin inhibited ovarian cancer cell proliferation and induced cell death by increasing reactive oxygen species (ROS) production and cytoplasmic Ca²⁺ levels as well as inducing loss of mitochondrial membrane potential (MMP). Moreover, chrysin activated mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT pathways in ES2 and OV90 cells in concentration-response experiments. Collectively, our results led us to propose that chrysin-induced apoptotic events are mediated by the activation of PI3K and MAPK pathways in human ovarian cancer cells.

Inhibitory effects of delphinidin on the proliferation of ovarian cancer cells via PI3K/AKT and ERK 1/2 MAPK signal transduction

Delphinidin is a member of the anthocyanidin family and is a natural pigment in red cabbage, berries, sweet potatoes and grapes. It possesses nutraceutical properties against various chronic diseases and types of cancer. However, little is known about its preventative effects on epithelial ovarian cancer, a disease that is associated with a low survival rate, a poor prognosis and a high rate of recurrence. The results of the present study demonstrated that the proliferation of SKOV3 cells decreased in a dose-dependent manner in response to treatment with delphinidin, and the phosphorylation of carcinogenic protein kinases associated with the progression of epithelial ovarian cancer was affected by delphinidin treatment. The levels of phosphorylated protein kinase B (AKT), ribosomal protein S6 kinase β-1 (P70S6K), ribosomal protein S (S6), extracellular signal-regulated kinase (ERK)1/2 and p38 were suppressed by increasing concentrations of delphinidin. Furthermore, the combination of certain pharmacological inhibitors, including phosphoinositide 3-kinase (PI3K; LY294002), ERK1/2 (U0126) and delphinidin significantly reduced the proliferation of SKOV3 cells and the phosphorylation of each of those target proteins. In addition, delphinidin treatment exerted anti-proliferative effects on paclitaxel-resistant SKOV3 cells, compared with treatment with paclitaxel alone. These results indicate that delphinidin inhibits the proliferation of SKOV3 cells through inactivation of PI3K/AKT and ERK1/2 mitogen-activated protein kinase signaling cascades, and that this cell signaling pathway may be a pivotal therapeutic target for the prevention of epithelial ovarian cancer, including paclitaxel-resistant ovarian cancer.

Gene Expression Profiling of Chemokines and Their Receptors in Low and High Grade Astrocytoma

Background: Despite intense interest in molecular characterization and searches for novel therapeutic targets, the glioblastoma remains a formidable clinical challenge. Among many contributors to gliomagenesis, chemokines have drawn special attention due to their involvement in a plethora of biological processes and pathological conditions. In the present study we aimed to elucidate any pro-gliomagenic chemokine axis and probable roles in development of glioblastoma multiforme (GBM). Method: An array of 84 chemokines, chemokine receptors and related genes were studied by real time PCR with comparison between low grade astrocytoma (diffuse astrocytoma – grade II) and high grade astrocytoma (glioblastoma multiforme – grade IV). Gene ontology analysis and database mining were performed to funnel down the important axis in GBM followed by validation at the protein level by immunohistochemistry on tissue microarrays. Results: Gene expression and gene ontology analysis identified CXCL8 as an important chemokine which was more frequently up-regulated in GBM as compared to diffuse astrocytoma. Further we demonstrated localization of CXCL8 and its receptors in glioblastoma possibly affecting autocrine and paracrine signalling that promotes tumor cell proliferation and neovascularisation with vascular mimicry. Conclusion: From these results CXCL8 appears to be an important gliomagenic chemokine which may be involved in GBM growth by promoting tumor cell proliferation and neovascularization via vascular mimicry. Further in vitro and in vivo investigations are required to explore its potential candidature in anti-GBM therapy.

Beside P53 and PTEN: Identification of molecular alterations of the RAS/MAPK and PI3K/AKT signaling pathways in high-grade serous ovarian carcinomas to determine potential novel therapeutic targets

Despite great histological and molecular heterogeneity, the clinical management of high-grade ovarian carcinomas remains unspecialized. As a major subgroup, high-grade serous ovarian carcinomas (HGSOCs) require novel therapies. In addition to utilizing conventional histological prognostic markers and performing oncogenetic investigations, the molecular diagnostic method of next generation sequencing (NGS) was performed to identify ‘druggable’ targets that could provide access to innovative therapy. The present study was performed in 45 HGSOC patients (mean age, 59.1 years; range, 25–87 years) with histologically proven HGSOC. Breast cancer 1/2 (BRCA1/2) germline mutations were screened in 17 patients with a familial or personal history of cancer, which was justified by oncogenetic investigations. Tumor protein 53 (P53) and phosphatase and tensin homolog (PTEN) expression were assessed in formalin-fixed paraffin-embedded tissues using immunohistochemistry. Somatic mutations of Kirsten rat sarcoma viral oncogene homolog, neuroblastoma RAS viral oncogene homolog (NRAS), B-Raf proto-oncogene, serine/threonine kinase, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA) and MET proto-oncogene, receptor tyrosine kinase (MET) were screened using NGS on DNA extracts from frozen tumor specimens obtained at diagnosis. With a median follow-up of 38 months (range, 6–93 months), 20 patients are alive, 10 patients are disease-free and 14 patients progressed within 6 months following platinum-based therapy. P53 overexpression was detected in 67% of patients and PTEN loss was detected in 38% of the patients. The overexpression of mutant P53 was found to be associated with a longer progression-free and overall survival. In total, 2 NRAS (exon 3), 3 PIK3CA (exon 5 and 10) and 5 MET mutations (exons 14 and 18) were detected. In HGSOCs, in addition to P53 and PTEN alterations, somatic genetic abnormalities can be detected using NGS and provide molecular rationale for targeted therapies, potentially offering novel therapeutic opportunities to patients.

Preferential effect of akt2-dependent signaling on the cellular viability of ovarian cancer cells in response to EGF

OBJECTIVE

Overexpression of the epidermal growth factor receptor (EGFR) is associated with the malignant phenotype in many cancers including ovarian cancer, which leads to increased cell proliferation and survival. In spite of emerging EGFR inhibitors as a potentially useful agent, they are largely ineffective in patients with advanced or recurrent ovarian cancers. Since Akt as a key downstream factor of EGFR is highly activated in some high grade serous ovarian tumors, the augmented Akt activation may attribute to irregular EGFR-mediated signaling observed in ovarian cancer. Here we investigated the differential effect of Akt on the EGF-induced cell viability in a panel of ovarian cancer cell lines.

METHODS

Cellular viability assay and western blot analysis were used to measure cell viability and expression levels of proteins, respectively. Knockdown of Akt was achieved with siRNA and stable transfection of expression vectors was performed.

RESULTS

Cellular viability increased in OVCAR-3 ovarian cancer cells exposed to EGF, but little to no difference was observed in the 5 other ovarian cancer cells including SKOV-3 cells despite of the expression of EGFR. In OVCAR-3 cells, EGF activated Erk and Akt, but an Erk inhibitor had no impact on cellular viability. On the other hand, the EGFR and PI3K inhibitors decreased EGF-induced cellular viability, indicating the involvement of Akt signaling. Although EGF activated Erk in SKOV-3 cells, the Akt activation was very weak as compared to OVCAR-3 cells. Furthermore, we observed a different expression of Akt isoforms: Akt1 was constitutively expressed in all tested ovarian cancer cells, while Akt3 was little expressed. Interestingly, Akt2 was highly expressed in OVCAR-3 cells. Knockdown of Akt2 blocked EGF-induced OVCAR-3 cell viability whereas knockdown for Akt1 and Erk1/2 had no significant effect. Stable transfection of Akt2 into SKOV-3 cells phosphorylated more Akt and enhanced cell viability in response to EGF.

CONCLUSIONS

Akt2-dependent signaling appears to play an important role in EGFR-mediated cellular viability in ovarian cancer and targeting specific Akt isoform may provide a potential therapeutic approach for EGFR-expressing ovarian cancers.

FSH in vitro versus LH in vivo: similar genomic effects on the cumulus

The use of gonadotropins to trigger oocyte maturation both in vivo and in vitro has provided precious and powerful knowledge that has significantly increased our understanding of the ovarian function. Moreover, the efficacy of most assisted reproductive technologies (ART) used in both humans and livestock species relies on gonadotropin input, mainly FSH and LH. Despite the significant progress achieved and the huge impact of gonadotropins, the exact molecular pathways of the two pituitary hormones, FSH and LH, still remain poorly understood. Moreover, these pathways may not be the same when moving from the in vivo to the in vitro context. This misunderstanding of the intricate synergy between these two hormones leads to a lack of consensus about their use mainly in vitro or in ovulation induction schedules in vivo. In order to optimize their use, additional work is thus required with a special focus on comparing the in vitro versus the in vivo effects. In this context, this overview will briefly summarize the downstream gene expression pathways induced by both FSH in vitro and LH in vivo in the cumulus compartment. Based on recent microarray comparative analysis, we are reporting that in vitro FSH stimulation on cumulus cells appears to achieve at least part of the gene expression activity after in vivo LH stimulation. We are then proposing that the in vitro FSH-response of cumulus cells have similitudes with the in vivo LH-response.

Antitumor properties of salinomycin on cisplatin-resistant human ovarian cancer cells in vitro and in vivo: involvement of p38 MAPK activation

In order to search for alternative agents to overcome chemoresistance during the treatment of ovarian cancer, this study aimed to examine the anticancer effects and action mechanism of salinomycin, a selective inhibitor of cancer stem cells, on cisplatin-resistant human ovarian cancer cell lines in vitro and in vivo. The concentration- (0.01-200 µM) and time‑dependent (24-72 h) growth inhibitory effects of salinomycin were observed in the ovarian cancer cell lines OV2008, C13, A2780, A2780-cp, SKOV3 and OVCAR3, by measuring cell viability using the resazurin reduction assay. The IC50 (24 h) range of salinomycin on the six cell lines was found to be 1.7-7.4 µM. After cisplatin-resistant C13 cells were treated with salinomycin, the percentage of apoptotic cells determined by flow cytometry was significantly increased, in a concentration- and time‑dependent manner. However, no cell cycle arrest was detected in the G1/G0, S and G2/M phases in the salinomycin‑treated and control cells. The Bio-Plex phosphoprotein 5-plex assay (Akt, IκB-α, ERK1/2, JNK and p38 MAPK) demonstrated a marked time- and concentration‑dependent increase in the phosphorylation of p38 MAPK, subsequent to salinomycin treatment. Moreover, salinomycin significantly suppressed tumor growth in a tumor xenograft model. These findings suggested that salinomycin efficiently inhibits the cisplatin-resistant human ovarian cancer cell line growth through the induction of apoptosis, potentially associated with the p38 MAPK activation.

Gonadotropin signalling in epithelial ovarian cancer

Ovarian cancer is the most lethal of all gynecologic malignancies, although its aetiology remains poorly understood. A role for the gonadotropins, follicle-stimulating hormone (FSH) and luteinising hormone (LH), has been implicated in a variety of different aspects of ovarian cancer tumorigenesis, including cellular proliferation, migration and invasion. This review focuses on the latest advances in knowledge concerning signalling pathways and functional consequences of gonadotropin action, including changes in protein-, miRNA- and gene expression, in epithelial ovarian cancer cells.

Newcastle disease virus induces apoptosis in cisplatin-resistant human lung adenocarcinoma A549 cells in vitro and in vivo

Cisplatin (DDP) is widely used in lung cancer chemotherapy. However, cisplatin resistance represents a major obstacle in effective clinical treatment. This study aims to investigate whether Newcastle disease virus (NDV) exhibits an oncolytic effect on cisplatin-resistant A549 lung cancer cells. We found that NDV induced A549/DDP cell apoptosis via the caspase pathway, particularly involving caspase-9, while the mitogen-activated protein kinase (MAPK) and Akt pathways also contributed to apoptotic induction. Furthermore, NDV displayed oncolytic effects in a mouse A549/DDP lung cancer model. Collectively, our data indicate that NDV could overcome the cisplatin resistance in lung cancer cells in vitro and in vivo.

Ovarian stem cell niche and follicular renewal in mammals

Stem cell niche consists of perivascular compartment, which connects the stem cells to the immune and vascular systems. During embryonic period, extragonadal primordial germ cells colonize coelomic epithelium of developing gonads. Subsequently, ovarian stem cells (OSC) produce secondary germ cells under the influence of OSC niche, including immune system-related cells and hormonal signaling. The OSC in fetal and adult human ovaries serve as a source of germ and granulosa cells. Lack of either granulosa or germ cell niche will result in premature ovarian failure in spite of the presence of OSC. During perinatal period, the OSC transdifferentiate into fibroblast-like cells forming the ovarian tunica albuginea resistant to environmental threats. They represent mesenchymal precursors of epithelial OSC during adulthood. The follicular renewal during the prime reproductive period (PRP) ensures that there are fresh eggs available for a healthy progeny. End of PRP is followed by exponentially growing fetal genetic abnormalities. The OSC are present in adult, aging, and postmenopausal ovaries, and differentiate in vitro into new oocytes. During in vitro development of large isolated oocytes reaching 200 μm in diameter, an ancestral mechanism of premeiotic nurse cells, which operates during oogenesis in developing ovaries from invertebrates to mammalian species, is utilized. In vitro developed eggs could be used for autologous IVF treatment of premature ovarian failure. Such eggs are also capable to produce parthenogenetic embryos like some cultured follicular oocytes. The parthenotes produce embryonic stem cells derived from inner cell mass, and these cells can serve as autologous pluripotent stem cells.

Expression of progranulin (Acrogranin/PCDGF/Granulin-Epithelin Precursor) in benign and malignant ovarian tumors and activation of MAPK signaling in ovarian cancer cell line

It has been recently demonstrated that progranulin is overexpressed in ovarian cancer and that this protein is involved in the stimulation of cell proliferation, malignancy, and chemoresistance in ovarian cancer. The goal of the present study was to establish the differences in progranulin expression among normal, benign, and malignant ovarian tissues and to identify the signal transduction pathways activated by progranulin in an ovarian cancer cell line. Compared with benign tumors and normal ovarian tissue, progranulin mRNA and protein were overexpressed in malignant tumors. Survival analysis by the Kaplan-Meier method showed a correlation between high mRNA expression levels with poor survival outcome. Progranulin activated the MAPK-signaling pathway in NIH-OVCAR-3 cells. Progranulin expression may be potentially involved in the pathogenesis and malignant progression of ovarian cancer, and thus may represent a therapeutic target for this particular malignancy.

Estrous cycle modulates ovarian carcinoma growth

PURPOSE

The effects of reproductive hormones on ovarian cancer growth are not well understood. Here, we examined the effects of estrous cycle variation and specific reproductive hormones on ovarian cancer growth.

EXPERIMENTAL DESIGN

We investigated the role of reproductive hormones in ovarian cancer growth using both in vivo and in vitro models of tumor growth.

RESULTS

In vivo experiments using the HeyA8 and SKOV3ip1 ovarian cancer models showed that tumor cell inoculation during proestrus significantly increased tumor burden (251-273%) compared with injection during the estrus phase. Treatment of ovariectomized mice with 17beta-estradiol resulted in a 404% to 483% increase in tumor growth compared with controls. Progestins had no significant effect, but did block estrogen-stimulated tumor growth. Tumors collected from mice sacrificed during proestrus showed increased levels of vascular endothelial growth factor (VEGF) and microvessel density compared with mice injected during estrus. HeyA8, SKOV3ip1, and mouse endothelial (MOEC) cells expressed estrogen receptor alpha and beta and progesterone receptor at the protein and mRNA levels, whereas 2774 ovarian cancer cells were estrogen receptor-negative. In vitro assays showed that 17beta-estradiol significantly increased ovarian cancer cell adhesion to collagen in estrogen receptor-positive, but not in estrogen receptor-negative cells. Additionally, 17beta-estradiol increased the migratory potential of MOEC cells, which was abrogated by the mitogen-activated protein kinase (MAPK) inhibitor, PD 09859. Treatment with 17beta-estradiol activated MAPK in MOEC cells, but not in HeyA8 or SKOV3ip1 cells.

CONCLUSION

Our data suggest that estrogen may promote in vivo ovarian cancer growth, both directly and indirectly, by making the tumor microenvironment more conducive for cancer growth.

Chemosensitisation by manganese superoxide dismutase inhibition is caspase-9 dependent and involves extracellular signal-regulated kinase 1/2

Chemoresistance and therapeutic selectivity are major obstacles to successful chemotherapy of ovarian cancer. Manganese superoxide disumutase (MnSOD) is an important antioxidant enzyme responsible for the elimination of superoxide radicals. We reported here that MnSOD was significantly elevated in ovarian cancer cells and its overexpression was one of the mechanisms that increased resistance to apoptosis in cancer cells. Knockdown of MnSOD by small-interfering RNA (siRNA) led to an increase in superoxide generation and sensitisation of ovarian cancer cells to the two front-line anti-cancer agents doxorubicin and paclitaxel whose action involved free-radical generation. This synergistic effect was not observed in non-transformed ovarian surface epithelial cells. Furthermore, our results revealed that this combination at the cellular level augmented activation of caspase-3 and caspase-9, but not caspase-8, suggesting involvement of an intrinsic apoptotic pathway. Evaluation of signalling pathways showed that MnSOD siRNA enhanced doxorubicin- and paclitaxel-induced phosphorylation of extracellular signal-regulated kinase 1/2. Akt activation was not affected. These results identify a novel chemoresistance mechanism in ovarian cancer, and show that combination of drugs capable of suppressing MnSOD with conventional chemotherapeutic agents may provide a novel strategy with a superior therapeutic index and advantage for the treatment of refractory ovarian cancer.

Curcumin induces G2/M arrest and apoptosis in cisplatin-resistant human ovarian cancer cells by modulating Akt and p38 MAPK

Curcumin, a major active component of turmeric, is known to induce apoptosis in several types of cancer cells, but little is known about its activity in chemoresistant cells. Hence, the aim of the present study was to investigate the anticancer properties of curcumin in cisplatin-resistant human ovarian cancer cells in vitro. The results indicated that curcumin inhibited the proliferation of both cisplatin-resistant (CR) and sensitive (CS) human ovarian cancer cells almost equally. Enhanced superoxide generation was observed in both CR and CS cells treated with curcumin. Curcumin induced G(2)/M phase cell-cycle arrest in CR cells by enhancing the p53 phosphorylation and apoptosis through the activation of caspase-3 followed by PARP degradation. Curcumin also inhibited the phosphorylation of Akt while the phosphorylation of p38 MAPK was enhanced. In summary, our results showed that curcumin inhibits the proliferation of cisplatin-resistant ovarian cancer cells through the induction of superoxide generation, G(2)/M arrest, and apoptosis.

Phenethyl isothiocyanate (PEITC) inhibits growth of ovarian cancer cells by inducing apoptosis: Role of caspase and MAPK activation

OBJECTIVE

Epithelial ovarian cancer has the highest mortality rate among gynecologic cancers. Chemotherapy is an essential component of its treatment. While isothiocyanates are known to possess chemopreventive effects against various cancers, yet little is known about their chemotherapeutic potential in ovarian cancer (OC). In the present study, we examined the antiproliferative and apoptotic effect of phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate on OVCAR-3 cells.

METHODS

Cytotoxic activity of PEITC on OVCAR-3 cells was determined using cell proliferation, apoptosis (DNA fragmentation and TUNEL assay) and caspase-activation studies. The role of PARP-1, Bax, and Bcl-2 in apoptosis was analyzed by Western blotting. Activation of JNK1/2, p38, Akt, ERK1/2, and c-Myc was examined by immunoblotting. Specific inhibitors of caspases, JNK1/2, p38, and MEK were used to corroborate these data.

RESULTS

PEITC was cytotoxic to OVCAR-3 cells, and inhibited proliferation in a dose-dependent fashion (IC(50) = 23.2 microM). PEITC induced apoptosis by activating caspase-3 and -9, without capsase-8 activation. Anti-apoptotic Bcl-2 levels were suppressed while pro-apoptotic Bax levels were enhanced. PEITC suppressed activation of Akt, ERK1/2, and the expression of transcription factor c-Myc, while simultaneously activating pro-apoptotic p38 and JNK1/2. Specific inhibitors of caspase-3 and -9, JNK1/2, and p38 reversed the cytotoxic effect of PEITC.

CONCLUSIONS

These findings demonstrate that PEITC exhibits cytotoxicity towards OVCAR-3 cells and induces apoptosis via caspase-9 and -3 pathways. PEITC inhibits Akt, ERK1/2 survival signaling, and c-Myc while simultaneously activating pro-apoptotic p38 and JNK1/2. Systematic preclinical and clinical trials with PEITC in ovarian cancer are indicated.

Transcriptomic analysis of an in vitro murine model of ovarian carcinoma: functional similarity to the human disease and identification of prospective tumoral markers and targets

Ovarian cancer is an aggressive disease of poor prognostic when detected at advanced stage. It is widely accepted that the ovarian surface epithelium plays a central role in disease etiology, but little is known about disease progression at the molecular level. To identify genes involved in ovarian tumorigenesis, we carried out a genome-wide transcriptomic analysis of six spontaneously transformed mouse ovarian surface epithelial (MOSE) cell lines, an in vitro model for human ovarian carcinoma. Loess normalization followed by statistical analysis with control of multiple testing resulted in 509 differentially expressed genes using an adjusted P-value < or = 0.05 as cut-off. The top 20 differentially expressed genes included 10 genes (Spp1, Cyp1b1, Btg1, Cfh, Mt1, Mt2, Igfbp5, Gstm1, Gstm2, and Esr1) implicated in various aspects of ovarian carcinomas, and other 3 genes (Gsto1, Lcn7, and Alcam) associated to breast cancer. Upon functional analysis, the majority of alterations affected genes involved in glutathione metabolism and MAPK signaling pathways. Interestingly, over 20% of the aberrantly expressed genes were related to extracellular components, suggestive of potential markers of disease progression. In addition, we identified the genes Pura, Cnn3, Arpc1b, Map4k4, Tgfb1i4, and Crsp2 correlated to in vivo tumorigenic parameters previously reported for these cells. Taken together, our findings support the utility of MOSE cells in studying ovarian cancer biology and as a source of novel diagnostic and therapeutic targets.

Acquisition of chemoresistance following discontinuous exposures to cisplatin is associated in ovarian carcinoma cells with progressive alteration of FAK, ERK and p38 activation in response to treatment

OBJECTIVE

Recurrence and cisplatin resistance that progressively develops in the course of treatments are major impediments in ovarian cancer therapy. We investigated the involvement of alterations of different signaling pathways in this acquired chemoresistance.

METHODS

We studied the activation of these pathways in a model of progressive acquisition of resistance that we established, by discontinuously exposing a sensitive ovarian carcinoma cell line, OAW42, to increasing concentrations of cisplatin.

RESULTS

OAW42-T1 and -T2 variants, which emerged after the first two treatments of OAW42 cells with 5 microg/ml cisplatin, showed enhanced but transient resistance. OAW42-R cells, obtained following successive reiterations of the treatment, displayed both a stronger resistance to cisplatin-induced apoptosis and an increased capacity to recover a normal proliferation after treatment. The measurement of DNA adducts demonstrated that the mechanisms leading to a decreased DNA platination could not explain the level of resistance of OAW42-R cells. The simultaneous study of activation pattern of key proteins of different signaling pathways revealed that cisplatin induced both activation of ERK and p38 and inhibition of P-FAK in the sensitive cells, whereas it progressively failed to elicit such a response in the resistant variants. In contrast, STAT3 and Akt did not seem to be involved in the acquired chemoresistance in our model.

CONCLUSIONS

Our results suggested that emergence of chemoresistance was accompanied with the progressive loss of ERK and p38 activation and with the maintenance of FAK activation in response to cisplatin, and they demonstrated that these alterations were early events in the course of treatments.

Oogenesis in adult mammals, including humans: a review

The origin of oocytes and primary follicles in ovaries of adult mammalian females has been a matter of dispute for over 100 yr. The prevailing belief that all oocytes in adult mammalian females must persist from the fetal period of life seems to be a uniquely retrogressive reproductive mechanism requiring humans to preserve their gametes from the fetal period for several decades. The utilization of modern techniques during last 10 yr clearly demonstrates that mammalian primordial germ cells originate from somatic cell precursors. This indicates that if somatic cells are precursors of germ cells, then somatic mutations can be passed on to progeny. Mitotically active germline stem cells have been described earlier in ovaries of adult prosimian primates and recently have been reported to also be present in the ovaries of adult mice. We have earlier shown that in adult human females, mesenchymal cells in the ovarian tunica albuginea undergo a mesenchymal-epithelial transition into ovarian surface epithelium cells, which differentiate sequentially into primitive granulosa and germ cells. Recently, we have reported that these structures assemble in the deeper ovarian cortex and form new follicles to replace earlier primary follicles undergoing atresia (follicular renewal). Our current observations also indicate that follicular renewal exists in rat ovaries, and human oocytes can differentiate from ovarian surface epithelium in fetal ovaries in vivo and from adult ovaries in vitro. These reports challenge the established dogma regarding the fetal origin of eggs and primary follicles in adult mammalian ovaries. Our data indicate that the pool of primary follicles in adult human ovaries does not represent a static but a dynamic population of differentiating and regressing structures. Yet, the follicular renewal may cease at a certain age, and this may predetermine the onset of the natural menopause or premature ovarian failure. A lack of follicular renewal in aging ovaries may cause an accumulation of spontaneously arising or environmentally induced genetic alterations of oocytes, and that may be why aging females have a much higher chance of having oocytes with more mutations in persisting primary follicles.

Origin of germ cells and formation of new primary follicles in adult human ovaries

Recent reports indicate that functional mouse oocytes and sperm can be derived in vitro from somatic cell lines. We hypothesize that in adult human ovaries, mesenchymal cells in the tunica albuginea (TA) are bipotent progenitors with a commitment for both primitive granulosa and germ cells. We investigated ovaries of twelve adult women (mean age 32.8 +/- 4.1 SD, range 27-38 years) by single, double, and triple color immunohistochemistry. We show that cytokeratin (CK)+ mesenchymal cells in ovarian TA differentiate into surface epithelium (SE) cells by a mesenchymal-epithelial transition. Segments of SE directly associated with ovarian cortex are overgrown by TA, forming solid epithelial cords, which fragment into small (20 micron) epithelial nests descending into the lower ovarian cortex, before assembling with zona pellucida (ZP)+ oocytes. Germ cells can originate from SE cells which cover the TA. Small (10 micron) germ-like cells showing PS1 meiotically expressed oocyte carbohydrate protein are derived from SE cells via asymmetric division. They show nuclear MAPK immunoexpression, subsequently divide symmetrically, and enter adjacent cortical vessels. During vascular transport, the putative germ cells increase to oocyte size, and are picked-up by epithelial nests associated with the vessels. During follicle formation, extensions of granulosa cells enter the oocyte cytoplasm, forming a single paranuclear CK+ Balbiani body supplying all the mitochondria of the oocyte. In the ovarian medulla, occasional vessels show an accumulation of ZP+ oocytes (25-30 microns) or their remnants, suggesting that some oocytes degenerate. In contrast to males, adult human female gonads do not preserve germline type stem cells. This study expands our previous observations on the formation of germ cells in adult human ovaries. Differentiation of primitive granulosa and germ cells from the bipotent mesenchymal cell precursors of TA in adult human ovaries represents a most sophisticated adaptive mechanism created during the evolution of female reproduction. Our data indicate that the pool of primary follicles in adult human ovaries does not represent a static but a dynamic population of differentiating and regressing structures. An essential mission of such follicular turnover might be elimination of spontaneous or environmentally induced genetic alterations of oocytes in resting primary follicles.