Similar protein expression profiles of ovarian and endometrial high-grade serous carcinomas

Pixantrone as a novel MCM2 inhibitor for ovarian cancer treatment

BACKGROUND

Mini-chromosome maintenance protein 2 (MCM2) is a potential target for the development of cancer therapeutics. However, small molecule inhibitors targeting MCM2 need further investigation.

METHODS

Molecular dynamics simulation was performed to identify active pockets in the MCM2 protein structure (6EYC). The active pocket was used as a docking model to discover MCM2 inhibitors by using structure-based virtual screening and surface plasmon resonance (SPR) assay. Furthermore, the efficacy of pixantrone targeting MCM2 in ovarian cancer was evaluated in vitro and in vivo.

RESULTS

Pixantrone was identified as a novel inhibitor of MCM2 by virtual screening. SPR binding affinity analysis confirmed the direct binding of pixantrone to MCM2 protein. Pixantrone significantly reduced the viability of ovarian cancer cells A2780 and SKOV3 in a dose- and time-dependent manner. In addition, pixantrone inhibited DNA replication, and induced cell cycle arrest and apoptosis in ovarian cancer cells via targeting MCM2. Knockdown of MCM2 could attenuate the inhibitory activity of pixantrone in ovarian cancer cells. Furthermore, pixantrone significantly suppressed ovarian cancer growth in the A2780 cell xenograft mouse model and showed favorable safety.

CONCLUSION

These findings suggest that pixantrone may be a promising drug for ovarian cancer patients by targeting MCM2 in the clinic.

Assessment of the differences in oncologic outcomes between patients with high-grade serous ovarian carcinoma and uterine serous carcinoma

AIM

To evaluate whether the recurrence rates, recurrence patterns, and survival outcomes differed according to the primary site of the tumor in patients with high-grade serous ovarian carcinoma (HGSOC) and uterine serous carcinoma (USC).

METHODS

The population of this multicenter retrospective study consisted of patients who had USC or HGSOC. Progression-free survival (PFS) and disease-specific survival (DSS) estimates were determined using the Kaplan-Meier method. Survival curves were compared using the log-rank test.

RESULTS

The study cohort consisted of 247 patients with HGSOC and 34 with USC. Recurrence developed in 118 (51.1%) in the HGSOC group and 14 (42.4%) in the USC group (p = 0.352). The median time to recurrence was 23.5 (range, 4-144) and 17 (range, 4-43) months in the HGSOC and USC groups, respectively (p = 0.055). The 3-year PFS was 52% in the HGSOC group and 47% in the USC group (p = 0.450). Additionally, 3-year DSS was 92% and 82% in the HGSOC and USC groups, respectively (p = 0.060).

CONCLUSIONS

HGSOC and USC are aggressive tumors with high recurrence and mortality rates in advanced stages. These two carcinomas, which are similar in molecular features and clinical management, may also have similar recurrence patterns, disease failure, and survival rates.

Role of the RNA-binding protein family in gynecologic cancers

Gynecological cancers pose a threat to women's health. Although early-stage gynecological cancers show good outcomes after standardized treatment, the prognosis of patients with advanced, met-astatic, and recurrent cancers is poor. RNA-binding proteins (RBPs) are important cellular proteins that interact with RNA through RNA-binding domains and participate extensively in post-transcriptional regulatory processes, such as mRNA alternative splicing, polyadenylation, intracellular localization and stability, and translation. Abnormal RBP expression affects the normal function of oncogenes and tumor suppressor genes in many malignancies, thus leading to the occurrence or progression of cancers. Similarly, RBPs play crucial roles in gynecological carcinogenesis. We summarize the role of RBPs in gynecological malignancies and explore their potential in the diagnosis and treatment of cancers. The findings summarized in this review may provide a guide for future research on the functions of RBPs.

Endometrial cancer diagnostic and prognostic algorithms based on proteomics, metabolomics, and clinical data: a systematic review

Endometrial cancer is the most common gynaecological malignancy in developed countries. Over 382,000 new cases were diagnosed worldwide in 2018, and its incidence and mortality are constantly rising due to longer life expectancy and life style factors including obesity. Two major improvements are needed in the management of patients with endometrial cancer, i.e., the development of non/minimally invasive tools for diagnostics and prognostics, which are currently missing. Diagnostic tools are needed to manage the increasing number of women at risk of developing the disease. Prognostic tools are necessary to stratify patients according to their risk of recurrence pre-preoperatively, to advise and plan the most appropriate treatment and avoid over/under-treatment. Biomarkers derived from proteomics and metabolomics, especially when derived from non/minimally-invasively collected body fluids, can serve to develop such prognostic and diagnostic tools, and the purpose of the present review is to explore the current research in this topic. We first provide a brief description of the technologies, the computational pipelines for data analyses and then we provide a systematic review of all published studies using proteomics and/or metabolomics for diagnostic and prognostic biomarker discovery in endometrial cancer. Finally, conclusions and recommendations for future studies are also given.

A comprehensive immunohistochemical analysis of IMP2 and IMP3 in 542 cases of ovarian tumors

BACKGROUND

IMP2 and IMP3 are mRNA binding proteins involved in carcinogenesis. We examined a large cohort of ovarian tumors with the aim to assess the value of IMP2 and IMP3 for differential diagnosis, and to assess their prognostic significance.

METHODS

Immunohistochemical analyses with antibodies against IMP2 and IMP3 were performed on 554 primary ovarian tumors including 114 high grade serous carcinomas, 100 low grade serous carcinomas, 124 clear cell carcinomas, 54 endometrioid carcinomas, 34 mucinous carcinomas, 75 mucinous borderline tumors, and 41 serous borderline tumors (micropapillary variant). The associations of overall positivity with clinicopathological characteristics were evaluated using the chi-squared test or Fisher's Exact test.

RESULTS

We found IMP2 expression (in more than 5% of tumor cells) in nearly all cases of all tumor types, so the prognostic meaning could not be analyzed. The positive IMP3 expression (in more than 5% of tumor cells) was most common in mucinous carcinomas (82%) and mucinous borderline tumors (81%), followed by high grade serous (67%) and clear cell carcinomas (67%). The expression was less frequent in endometrioid carcinomas (39%), low grade serous carcinomas (23%), and micropapillary variant of serous borderline tumors (20%). Prognostic significance of IMP3 could be evaluated only in low grade serous carcinomas in the case of relapse-free survival, where negative cases showed better RFS (p = 0.033).

CONCLUSION

Concerning differential diagnosis our results imply that despite the differences in expression in the different ovarian tumor types, the practical value for diagnostic purposes is limited. Contrary to other solid tumors, we did not find prognostic significance of IMP3 in ovarian cancer, with the exception of RFS in low grade serous carcinomas. However, the high expression of IMP2 and IMP3 could be of predictive value in ovarian carcinomas since IMP proteins are potential therapeutical targets.

Anti-lipolysis-stimulated lipoprotein receptor monoclonal antibody as a novel therapeutic agent for endometrial cancer

Background

Endometrial cancer (EC) is a common gynecologic malignancy and patients with advanced and recurrent EC have a poor prognosis. Although chemotherapy is administered for those patients, the efficacy of current chemotherapy is limited. Therefore, it is necessary to develop novel therapeutic agents for EC. In this study, we focused on lipolysis-stimulated lipoprotein receptor (LSR), a membrane protein highly expressed in EC cells, and developed a chimeric chicken–mouse anti-LSR monoclonal antibody (mAb). This study investigated the antitumor effect of an anti-LSR mAb and the function of LSR in EC.

Methods

We examined the expression of LSR in 228 patients with EC using immunohistochemistry and divided them into two groups: high-LSR (n = 153) and low-LSR groups (n = 75). We developed a novel anti-LSR mAb and assessed its antitumor activity in an EC cell xenograft mouse model. Pathway enrichment analysis was performed using protein expression data of EC samples. LSR-knockdown EC cell lines (HEC1 and HEC116) were generated by transfected with small interfering RNA and used for assays in vitro.

Results

High expression of LSR was associated with poor overall survival (hazard ratio: 3.53, 95% confidence interval: 1.35–9.24, p = 0.01), advanced stage disease (p = 0.045), deep myometrial invasion (p = 0.045), and distant metastasis (p < 0.01). In EC with deep myometrial invasion, matrix metalloproteinase (MMP) 2 was highly expressed along with LSR. Anti-LSR mAb significantly inhibited the tumor growth in EC cell xenograft mouse model (tumor volume, 407.1 mm³versus 726.3 mm³, p = 0.019). Pathway enrichment analysis identified the mitogen-activated protein kinase (MAPK) pathway as a signaling pathway associated with LSR expression. Anti-LSR mAb suppressed the activity of MAPK in vivo. In vitro assays using EC cell lines demonstrated that LSR regulated cell proliferation, invasion, and migration through MAPK signaling, particularly MEK/ERK signaling and membrane-type 1 MMP (MT1-MMP) and MMP2. Moreover, ERK1/2-knockdown suppressed cell proliferation, invasion, migration, and the expression of MT1-MMP and MMP2.

Conclusions

Our results suggest that LSR contributes to tumor growth, invasion, metastasis, and poor prognosis of EC through MAPK signaling. Anti-LSR mAb is a potential therapeutic agent for EC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09789-6.

The role of insulin-like growth factor 2 mRNA binding proteins in female reproductive pathophysiology

Insulin-like growth factor 2 (IGF2) mRNA binding proteins (IMPs) family belongs to a highly conserved family of RNA-binding proteins (RBPs) and is responsible for regulating RNA processing including localization, translation and stability. Mammalian IMPs (IMP1-3) take part in development, metabolism and tumorigenesis, where they are believed to play a major role in cell growth, metabolism, migration and invasion. IMPs have been identified that are expressed in ovary, placenta and embryo. The up-to-date evidence suggest that IMPs are involved in folliculogenesis, oocyte maturation, embryogenesis, implantation, and placentation. The dysregulation of IMPs not only contributes to carcinogenesis but also disturbs the female reproduction, and may participate in the pathogenesis of reproductive diseases and obstetric syndromes, such as polycystic ovary syndrome (PCOS), pre-eclampsia (PE), gestational diabetes mellitus (GDM) and gynecological tumors. In this review, we summarize the role of IMPs in female reproductive pathophysiology, and hope to provide new insights into the identification of potential therapeutic targets.

Phase II study of niraparib in recurrent or persistent rare fraction of gynecologic malignancies with homologous recombination deficiency (JGOG2052)

Background

Poly (adenosine diphosphate)-ribose polymerase (PARP) inhibitors for tumors with homologous recombination deficiency (HRD), including pathogenic mutations in BRCA1/2, have been developed. Genomic analysis revealed that about 20% of uterine leiomyosarcoma (uLMS) have HRD, including 7.5%–10% of BRCA1/2 alterations and 4%–6% of carcinomas of the uterine corpus, and 2.5%–4% of the uterine cervix have alterations of BRCA1/2. Preclinical and clinical case reports suggest that PARP inhibitors may be effective against those targets. The Japanese Gynecologic Oncology Group (JGOG) is now planning to conduct a new investigator-initiated clinical trial, JGOG2052.

Methods

JGOG2052 is a single-arm, open-label, multi-center, phase 2 clinical trial to evaluate the efficacy and safety of niraparib monotherapy for a recurrent or persistent rare fraction of gynecologic malignancies with BRCA1/2 mutations except for ovarian cancers. We will independently consider the effect of niraparib for uLMS or other gynecologic malignancies with BRCA1/2 mutations (cohort A, C) and HRD positive uLMS without BRCA1/2 mutations (cohort B). Participants must have 1–3 lines of previous chemotherapy and at least one measurable lesion according to RECIST (v.1.1). Niraparib will be orally administered once a day until lesion exacerbation or unacceptable adverse events occur. Efficacy will be evaluated by imaging through an additional computed tomography scan every 8 weeks. Safety will be measured weekly in cycle 1 and every 4 weeks after cycle 2 by blood tests and physical examinations. The sample size is 16–20 in each of cohort A and B, and 31 in cohort C. Primary endpoint is the objective response rate.

Trial Registration

Japan Primary Registries Network (JPRN) Identifier: jRCT2031210264

Hsa_circ_0001756 promotes ovarian cancer progression through regulating IGF2BP2-mediated RAB5A expression and the EGFR/MAPK signaling pathway

Hsa_circ_0001756 was reported to be upregulated in serum samples of ovarian cancer (OC) patients and may serve as a potential OC biomarker. This study aimed to investigate the role and molecular mechanisms of hsa_circ_0001756 in OC procession. Herein, we detected the expression of hsa_circ_0001756 in OC tissues and cell lines with RT-qPCR assay, which showed that hsa_circ_0001756 was upregulated in OC tissues and cell lines. Then small interfering RNA targeting hsa_circ_0001756 (si-hsa_circ_0001756) was transfected into SKOV3 and A2780 cells, and the proliferation, invasion, and expression of epithelial-mesenchymal transition (EMT) marker proteins were determined with CCK-8, Transwell and Western blotting assays, respectively. We found that hsa_circ_0001756 knockdown inhibited OC cell proliferation, invasion and EMT. Moreover, RNA pull-down assay verified the binding between hsa_circ_0001756 and IGF2 mRNA binding protein 2 (IGF2BP2), and rescue experiments indicated that IGF2BP2 overexpression reversed the effects of has_circ_0001756 knockdown on OC cell functions. Co-IP assay verified IGF2BP2 could interact with RAB GTPase 5A (RAB5A) protein. Then SKOV3 cells were transfected with si-IGF2BP2 alone or together with pcDNA-RAB5A, followed by the detection of SKOV3 cell functions. We found that IGF2BP2 knockdown inhibited OC cell proliferation, invasion, and EMT, while RAB5A overexpression reversed these effects. Finally, SKOV3 cells transfected with si-hsa_circ_0001756 were injected into nude mice through tail vein. Hsa_circ_0001756 knockdown significantly inhibited the xenograft tumor growth of OC in vivo. In conclusion, hsa_circ_0001756 knockdown inhibits OC cell proliferation, invasion, and EMT, and reduces xenograft tumor growth by suppressing IGF2BP2-mediated RAB5A expression and blocking the EGFR/MAPK signaling pathway.

RNA-binding proteins in ovarian cancer: a novel avenue of their roles in diagnosis and treatment

Ovarian cancer (OC), an important cause of cancer-related death in women worldwide, is one of the most malignant cancers and is characterized by a poor prognosis. RNA-binding proteins (RBPs), a class of endogenous proteins that can bind to mRNAs and modify (or even determine) the amount of protein they can generate, have attracted great attention in the context of various diseases, especially cancers. Compelling studies have suggested that RBPs are aberrantly expressed in different cancer tissues and cell types, including OC tissues and cells. More specifically, RBPs can regulate proliferation, apoptosis, invasion, metastasis, tumorigenesis and chemosensitivity and serve as potential therapeutic targets in OC. Herein, we summarize what is currently known about the biogenesis, molecular functions and potential roles of human RBPs in OC and their prospects for application in the clinical treatment of OC.

Identification of the function and mechanism of m6A reader IGF2BP2 in Alzheimer's disease

Alzheimer’s disease, the most common form of dementia in the elderly, is a kind of neurodegenerative disease. However, its pathogenesis and diagnosis remain unclear. M6A is related to nervous system development and neurodegenerative diseases. Here in this study, using multiple RNA-seq datasets of Alzheimer’s brain tissues, along with bioinformatic analysis, we innovatively found that m6A reader protein IGF2BP2 was abnormally highly expressed in Alzheimer’s patients. After compared between Alzheimer’s and normal brain samples, and between IGF2BP2- high and IGF2BP2- low subgroups of Alzheimer’s patients, we took the shared differentially expressed genes as the relevant gene sets of IGF2PB2 affecting Alzheimer’s disease occurrence for subsequent analysis. Then, weight gene correlation analysis was conducted and 17 functional modules were identified. The module that most positively correlated with Alzheimer’s disease and IGF2PB2-high subgroups were mainly participated in ECM receptor interaction, focal adhesion, cytokine-cytokine receptor interaction, and TGF-beta signaling pathway. Afterwards, a hub gene-based model including 20 genes was constructed by LASSO regression and validated by ROC curve for Alzheimer diagnosis. Finally, we preliminarily elucidated that IGF2BP2 could bind with mRNAs in a m6A-dependent manner. This study first elucidates the pathogenic role of IGF2BP2 in Alzheimer’s disease. IGF2BP2 and its relevant m6A modifications are potential to be new diagnostic and therapeutic targets for Alzheimer’s patients.

Recent Developments and Applications of Quantitative Proteomics Strategies for High-Throughput Biomolecular Analyses in Cancer Research

Innovations in medical technology and dedicated focus from the scientific community have inspired numerous treatment strategies for benign and invasive cancers. While these improvements often lend themselves to more positive prognoses and greater patient longevity, means for early detection and severity stratification have failed to keep pace. Detection and validation of cancer-specific biomarkers hinges on the ability to identify subtype-specific phenotypic and proteomic alterations and the systematic screening of diverse patient groups. For this reason, clinical and scientific research settings rely on high throughput and high sensitivity mass spectrometry methods to discover and quantify unique molecular perturbations in cancer patients. Discussed within is an overview of quantitative proteomics strategies and a summary of recent applications that enable revealing potential biomarkers and treatment targets in prostate, ovarian, breast, and pancreatic cancer in a high throughput manner.

CD70 antibody-drug conjugate: A potential novel therapeutic agent for ovarian cancer

This study aimed to investigate the cytotoxicity of a cluster of differentiation 70 antibody-drug conjugate (CD70-ADC) against ovarian cancer in in vitro and in vivo xenograft models. CD70 expression was assessed in clinical samples by immunohistochemical analysis. Western blotting and fluorescence-activated cell sorting analyses were used to determine CD70 expression in the ovarian cancer cell lines A2780 and SKOV3, and in the cisplatin-resistant ovarian cancer cell lines A2780cisR and SKOV3cisR. CD70 expression after cisplatin exposure was determined in A2780 cells transfected with mock- or nuclear factor (NF)-κB-p65-small interfering RNA. We developed an ADC with an anti-CD70 monoclonal antibody linked to monomethyl auristatin F and investigated its cytotoxic effect. We examined 63 ovarian cancer clinical samples; 43 (68.3%) of them expressed CD70. Among patients with advanced stage disease (n = 50), those who received neoadjuvant chemotherapy were more likely to exhibit high CD70 expression compared to those who did not (55.6% [15/27] vs 17.4% [4/23], P < .01). CD70 expression was confirmed in A2780cisR, SKOV3, and SKOV3cisR cells. Notably, CD70 expression was induced after cisplatin treatment in A2780 mock cells but not in A2780-NF-κB-p65-silenced cells. CD70-ADC was cytotoxic to A2780cisR, SKOV3, and SKOV3cisR cells, with IC₅₀ values ranging from 0.104 to 0.341 nmol/L. In A2780cisR and SKOV3cisR xenograft models, tumor growth in CD70-ADC treated mice was significantly inhibited compared to that in the control-ADC treated mice (A2780cisR: 32.0 vs 1639.0 mm³ , P < .01; SKOV3cisR: 232.2 vs 584.9 mm³ , P < .01). Platinum treatment induced CD70 expression in ovarian cancer cells. CD70-ADC may have potential therapeutic implications in the treatment of CD70 expressing ovarian cancer.

Establishment and validation of an RNA binding protein-associated prognostic model for ovarian cancer

Background

Ovarian cancer (OC) is one of the most common gynecological malignant tumors worldwide, with high mortality and a poor prognosis. As the early symptoms of malignant ovarian tumors are not obvious, the cause of the disease is still unclear, and the patients’ postoperative quality of life of decreases. Therefore, early diagnosis is a problem requiring an urgent solution.

Methods

We obtained the gene expression profiles of ovarian cancer and normal samples from TCGA and GTEx databases for differential expression analysis. From existing literature reports, we acquired the RNA-binding protein (RBP) list for the human species. Utilizing the online tool Starbase, we analyzed the interaction relationship between RBPs and their target genes and selected the modules of RBP target genes through Cytoscape. Finally, univariate and multivariate Cox regression analyses were used to determine the prognostic RBP signature.

Results

We obtained 527 differentially expressed RBPs, which were involved in many important cellular events, such as RNA splicing, the cell cycle, and so on. We predicted several target genes of RBPs, constructed the interaction network of RBPs and their target genes, and obtained many modules from the Cytoscape analysis. Functional enrichment of RBP target genes also includes these important biological processes. Through Cox regression analysis, OC prognostic RBPs were identified and a 10-RBP model constructed. Further analysis showed that the model has high accuracy and sensitivity in predicting the 3/5-year survival rate.

Conclusions

Our study identified differentially expressed RBPs and their target genes in OC, and the results promote our understanding of the molecular mechanism of ovarian cancer. The current study could develop novel biomarkers for the diagnosis, treatment, and prognosis of OC and provide new ideas and prospects for future clinical research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00777-1.

Clinical Significance of an m6A Reader Gene, IGF2BP2, in Head and Neck Squamous Cell Carcinoma

The importance of N6-methyladenosine (m6A) in tumor recurrence and prognosis has been recognized in recent years. The role of m6A readers, such as insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), in regulating head and neck squamous cell carcinoma (HNSCC) remains unclear. We, therefore, assessed the prognostic role of IGF2BP2 in HNSCC using openly available data from The Cancer Genome Atlas (TCGA) in conjunction with HNSCC patient sample immunohistochemistry (n = 36). The correlation between IGF2BP2 expression and clinical characteristics was then examined. The role of IGF2BP2 in prognosis was assessed by Kaplan-Meier curves and Cox analysis. Finally, TCGA data was used to explore possible carcinogenic mechanisms with multi-GSEA (gene set enrichment analysis). Analysis of TCGA data and IHC results revealed that IGF2BP2 was upregulated in HNSCC tumor tissues, and the expression level was related to the T stage. Simultaneously, Kaplan-Meier curves and Cox analysis indicated that highly expressed IGF2BP2 correlated with poor prognosis and that IGF2BP2 was a potential prognostic factor for HNSCC. Gene set enrichment analysis revealed that scavenging and degradation, synthesis and metabolism, cell growth, death and motility, and cancer pathways were differentially enriched in patients with high IGF2BP2 expression. Our results demonstrate that IGF2BP2 plays an important role in tumor progression and may serve as an important biological prognostic factor for HNSCC.

Small Cell Carcinomas of the Uterine Cervix and Lung: Proteomics Reveals Similar Protein Expression Profiles

Objective

The phenotypic and pathological features of small cell cervical carcinoma (SMCC) and small small cell lung cancer (SCLC) are very similar; thus, the chemotherapy regimens used for the rare SMCC have been routinely based on regimens used for common SCLC. We set out to explore the protein expression profile similarities between these 2 cancers to prove that linking their therapeutic regimens is justified, with a secondary aim of finding tumor-specific proteins to use as additional biomarkers for more accurate diagnosis of SMCC, and potentially to use as therapeutic targets.

Methods

Protein expression analysis was performed for 3 cases of SMCC and 1 example each of SCLC, mucinous adenocarcinoma of the cervix (MACC), lung mucinous adenocarcinoma (MACL), and squamous cell carcinoma of the cervix (SCC). We used cancer tissue–originated spheroids (CTOS) and isobaric tags for relative and absolute quantitation (iTRAQ)–based comprehensive and quantitative protein expression profile analysis. Expression in corresponding clinical samples was verified by immunohistochemistry.

Results

Rather than organ of origin–specific patterns, the SMCC and SCLC samples revealed remarkably similar protein expression profiles—in agreement with their matching tumor pathology phenotypes. Sixteen proteins were expressed at least 2-fold higher in both small cell carcinomas (SMCC and SCLC) than in MACC or SCC. Immunohistochemical analysis confirmed higher expression of creatine kinase B-type in SMCC, compared with MACC and SCC.

Conclusions

We demonstrate a significant overlapping similarity of protein expression profiles of lung and cervical small cell carcinomas despite the significant differences in their organs of origin.

Quantitative analysis of the mitochondrial proteome in human ovarian carcinomas

Mitochondria play important roles in growth, signal transduction, division, tumorigenesis and energy metabolism in epithelial ovarian carcinomas (EOCs) without an effective biomarker. To investigate the proteomic profile of EOC mitochondrial proteins, a 6-plex isobaric tag for relative and absolute quantification (iTRAQ) proteomics was used to identify mitochondrial expressed proteins (mtEPs) in EOCs relative to controls, followed by an integrative analysis of the identified mtEPs and the Cancer Genome Atlas (TCGA) data from 419 patients. A total of 5115 quantified proteins were identified from purified mitochondrial samples, and 262 proteins were significantly related to overall survival in EOC patients. Furthermore, 63 proteins were identified as potential biomarkers for the development of an EOC, and our findings were consistent with previous reports on a certain extent. Pathway network analysis identified 70 signaling pathways. Interestingly, the results demonstrated that cancer cells exhibited an increased dependence on mitophagy, such as peroxisome, phagosome, lysosome, valine, leucine and isoleucine degradation and fatty acid degradation pathways, which might play an important role in EOC invasion and metastasis. Five proteins (GLDC, PCK2, IDH2, CPT2 and HMGCS2) located in the mitochondrion and enriched pathways were selected for further analysis in an EOC cell line and tissues, and the results confirmed reliability of iTRAQ proteomics. These findings provide a large-scale mitochondrial proteomic profiling with quantitative information, a certain number of potential protein biomarkers and a novel vision in the mitophagy bio-mechanism of a human ovarian carcinoma.

Mass spectrometry-based proteomics techniques and their application in ovarian cancer research

Ovarian cancer has emerged as one of the leading cause of gynecological malignancies. So far, the measurement of CA125 and HE4 concentrations in blood and transvaginal ultrasound examination are essential ovarian cancer diagnostic methods. However, their sensitivity and specificity are still not sufficient to detect disease at the early stage. Moreover, applied treatment may appear to be ineffective due to drug-resistance. Because of a high mortality rate of ovarian cancer, there is a pressing need to develop innovative strategies leading to a full understanding of complicated molecular pathways related to cancerogenesis. Recent studies have shown the great potential of clinical proteomics in the characterization of many diseases, including ovarian cancer. Therefore, in this review, we summarized achievements of proteomics in ovarian cancer management. Since the development of mass spectrometry has caused a breakthrough in systems biology, we decided to focus on studies based on this technique. According to PubMed engine, in the years 2008-2010 the number of studies concerning OC proteomics was increasing, and since 2010 it has reached a plateau. Proteomics as a rapidly evolving branch of science may be essential in novel biomarkers discovery, therapy decisions, progression predication, monitoring of drug response or resistance. Despite the fact that proteomics has many to offer, we also discussed some limitations occur in ovarian cancer studies. Main difficulties concern both complexity and heterogeneity of ovarian cancer and drawbacks of the mass spectrometry strategies. This review summarizes challenges, capabilities, and promises of the mass spectrometry-based proteomics techniques in ovarian cancer management.

Subcellular localization of MCM2 correlates with the prognosis of ovarian clear cell carcinoma

Highly malignant tumors overexpress the minichromosome maintenance 2 (MCM2) protein in the nucleus, which is associated with advanced tumor grade, advanced stage, and poor prognosis. In this study, we showed that MCM2 is highly expressed in clinical samples of ovarian clear cell carcinoma. Although MCM2 expression was mainly localized to the nuclei as in other cancers, a few cases exhibited cytoplasmic localization of MCM2. Surprisingly, tumor samples with cytoplasmic MCM2 demonstrated excellent prognosis, showing 100% survival during the observation period of more than 200 months. However, cases with nuclear expression of MCM2 exhibited approximately 78% 5-year-survival rate. In a previous study, we showed that Friend leukemia virus (FLV) envelope protein gp70 bound to MCM2, impaired its nuclear translocation, and enhanced DNA damage-induced apoptosis in FLV-infected hematopoietic cells with high levels of MCM2. As expected, clear cell carcinoma cells with cytoplasmic expression of MCM2 exhibited significantly higher apoptotic cell ratio than that of cells with nuclear MCM2 expression. In vitro experiments using ovarian cancer cells with cytoplasmic expression of MCM2 demonstrated that transfection of MCM2-ΔN enhanced DNA damage-induced apoptosis. Therefore, cytoplasmic localization of MCM2 significantly correlated with increased apoptosis in clear cell carcinoma cells, resulting in improved prognosis.

Intratumoral Delivery of an Adenoviral Vector Carrying the SOCS-1 Gene Enhances T-Cell-Mediated Antitumor Immunity By Suppressing PD-L1

Ovarian cancer is the leading cause of gynecologic cancer-related deaths and novel therapeutic strategies are required. Programmed cell death 1 and programmed cell death ligand 1 (PD-L1), which are key mediators of host immune tolerance, are associated with ovarian cancer progression. Recent evidence indicates the importance of IFNγ-induced PD-L1 for immune tolerance in ovarian cancer. This study aimed to reveal the therapeutic potential of suppressor of cytokine signaling 1 (SOCS-1), an endogenous inhibitor of the Janus kinase (JAK)-STAT signaling pathway, for the treatment of ovarian cancer. IHC assessment revealed that patients with ovarian cancer with high intratumoral STAT1 activation exhibited poor prognosis compared with patients with low STAT1 activation (P < 0.05). Stimulation of OVISE, OVTOKO, OV2944-HM-1 (HM-1), and CT26 cell lines with IFNγ induced STAT1 phosphorylation and PD-L1 expression. Adenovirus-mediated SOCS-1 gene delivery (AdSOCS-1) in HM-1 and CT26 cells in vitro potently inhibited IFNγ-induced STAT1 phosphorylation and PD-L1 upregulation, similar to the addition of JAK inhibitor I, but failed to inhibit their proliferation. Notably, intratumoral injection of AdSOCS-1, but not AdLacZ, significantly inhibited the tumor growth of HM-1 and CT26 cells subcutaneously transplanted in immunocompetent syngeneic mice. AdSOCS-1 reduced PD-L1 expression on tumors and restored the activation of tumor-infiltrating CD8⁺ T cells. Moreover, the antitumor effect of AdSOCS-1 was significantly attenuated by PD-L1 Fc-fusion protein administration in vivo, suggesting that the effect of AdSOCS-1 is mainly attributable to enhancement of tumor immunity. This study highlights the potential clinical utility of SOCS-1 as an immune checkpoint inhibitor. Mol Cancer Ther; 17(9); 1941-50. ©2018 AACR.

Ovarian Cancer and BRCA1/2 Testing: Opportunities to Improve Clinical Care and Disease Prevention

Without prevention or screening options available, ovarian cancer is the most lethal malignancy of the female reproductive tract. High-grade serous ovarian cancer (HGSOC) is the most common histologic subtype, and the role of germline BRCA1/2 mutation in predisposition and prognosis is established. Given the targeted treatment opportunities with PARP inhibitors, a predictive role for BRCA1/2 mutation has emerged. Despite recommendations to provide BRCA1/2 testing to all women with histologically confirmed HGSOC, uniform implementation remains challenging. The opportunity to review and revise genetic screening and testing practices will identify opportunities, where universal adoption of BRCA1/2 mutation testing will impact and improve treatment of women with ovarian cancer. Improving education and awareness of genetic testing for women with cancer, as well as the broader general community, will help focus much-needed attention on opportunities to advance prevention and screening programs in ovarian cancer. This is imperative not only for women with cancer and those at risk of developing cancer but also for their first-degree relatives. In addition, BRCA1/2 testing may have direct implications for patients with other types of cancers, many of which are now being found to have BRCA1/2 involvement.