RING finger protein 187 as a novel potential biomarker for predicting the prognosis of ovarian carcinoma in 2 cancer centers

RING finger protein 187 (RNF187) has been used to predict prognosis of several human carcinomas. However, the clinicopathologic and prognostic implication of RNF187 expression in ovarian carcinomas remains not to be evaluated. The aim of this study was to explore the clinicopathologic and the prognostic significance of RNF187 in patients with ovarian carcinomas. Expression levels of RNF187 protein were investigated by immunohistochemical staining based on tissue-microarray composed of 147 patients with ovarian carcinomas. Receiver operating characteristic curve analysis was used to select the ideal cut-off value of RNF187 expression in ovarian carcinoma, and then analyze the correlation between the status of RNF187 expression and various clinicopathologic variables by chi-square test. Univariate analysis was employed to investigate the association between clinicopathologic variables and prognosis of patients by Kaplan-Meier method. Multivariate analysis was performed to identify the independent prognostic factors by the Cox regression model. Our results demonstrated that high expression of RNF187 was significantly associated with late FIGO stage, high histologic grade and pN1 stage in ovarian carcinoma (P < 0.05). Univariate analysis uncovered patients with the high expression of RNF187 have the worse overall survival and disease-free survival (P < 0.05). More surprisingly, multivariate analysis determined that the RNF187 expression was served as an independent prognostic factor in ovarian carcinoma. The high expression of RNF187 might influence a more aggressive biological behavior in ovarian carcinoma. Therefore, RNF187 expression could be useful to act as a new independent prognostic biomarker for patients with ovarian carcinoma.

Intraoperative Raman-Guided Chemo-Photothermal Synergistic Therapy of Advanced Disseminated Ovarian Cancers

Abdominal miliary spread and metastasis is one of the most aggressive features in advanced ovarian cancer patients. The current standard treatment of advanced ovarian cancer is cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). However, most patients cannot receive optimal CRS outcomes due to the extreme difficulty of completely excising all microtumors during operation. Though HIPEC can improve prognosis, treatment is untargeted and may damage healthy organs and cause complications. New strategies for precise detection and complete elimination of disseminated microtumors without side effects are therefore highly desirable. Here, cisplatin-loaded gap-enhanced Raman tags (C-GERTs) are designed specifically for the intraoperative detection and elimination of unresectable disseminated advanced ovarian tumors. With unique and strong Raman signals, good biocompatibility, decent plasmonic photothermal conversion, and good drug loading capacity, C-GERTs enable detection and specific elimination of microtumors with a minimum diameter of 1 mm via chemo-photothermal synergistic therapy, causing minimal side effects and significantly prolonging survival in mice. The results demonstrate that C-GERTs-based chemo-photothermal synergistic therapy can effectively control the spread of disseminated tumors in mice and has potential as a safe and powerful method for treatment of advanced ovarian cancers, to improve survival and life quality of patients.

Anticancer Activity of Toxins from Bee and Snake Venom-An Overview on Ovarian Cancer

Cancer represents the disease of the millennium, a major problem in public health. The proliferation of tumor cells, angiogenesis, and the relationship between the cancer cells and the components of the extracellular matrix are important in the events of carcinogenesis, and these pathways are being used as targets for new anticancer treatments. Various venoms and their toxins have shown possible anticancer effects on human cancer cell lines, providing new perspectives in drug development. In this review, we observed the effects of natural toxins from bee and snake venom and the mechanisms through which they can inhibit the growth and proliferation of cancer cells. We also researched how several types of natural molecules from venom can sensitize ovarian cancer cells to conventional chemotherapy, with many toxins being helpful for developing new anticancer drugs. This approach could improve the efficiency of standard therapies and could allow the administration of decreased doses of chemotherapy. Natural toxins from bee and snake venom could become potential candidates for the future treatment of different types of cancer. It is important to continue these studies concerning therapeutic drugs from natural resource and, more importantly, to investigate their mechanism of action on cancer cells.

Isoalantolactone induces autophagic cell death in SKOV₃ human ovarian carcinoma cells via upregulation of PEA-15

We investigated the effects of isoalantolactone on cell growth inhibition and underlying cell death mechanisms in SKOV3 human ovarian cancer cells. The effects of isoalantolactone on cell proliferation and cell cycle were examined by EdU incorporation assay and DNA content assay. Western blotting was performed to determine the protein expression effects of isoalantolactone on cell cycle‑related proteins, autophagic regulators and PEA‑15. Autophagic vacuoles were observed by acridine orange staining. PEA‑15 knockdown by siRNA was used to confirm that PEA‑15 was involved in isoalantolactone‑induced autophagy of SKOV3 cells. Isoalantolactone inhibited the viability and proliferation of SKOV3 cells in a dose‑ and time‑dependent fashion. Isoalantolactone induced cell cycle arrest at G2/M phase and decreased the expression of cell cycle‑related proteins cyclin B1 and CDK1 in SKOV3 cells. Accordingly, isoalantolactone also induced SKOV3 cell autophagy via accumulation of autophagic vacuoles in the cytoplasm, increased Beclin1 protein expression, and increased LC3 cleavage. Furthermore, we observed that isoalantolactone‑induced autophagy was through increased PEA‑15 expression and the phosphorylation of ERK, whereas less change was observed to autophagy on SKOV3 cells through PEA‑15 knockdown by siRNA. Isoalantolactone‑induced autophagic cell death was further confirmed by pretreatment with the autophagy inhibitor 3‑methyladenine (3‑MA). In conclusion, isoalantolactone induced cell cycle arrest and autophagy and inhibited cell proliferation of SKOV3 cells via the upregulated PEA‑15 expression and the phosphorylation of ERK.

Laparoscopy for diagnosing resectability of disease in patients with advanced ovarian cancer

BACKGROUND

The presence of residual tumour after primary debulking surgery is the most important prognostic factor in patients with advanced ovarian cancer. In up to 60% of cases, residual tumour of more than 1 cm is left behind, stressing the necessity of accurately selecting those patients who should be treated with primary debulking surgery and those who should receive neoadjuvant chemotherapy instead.

OBJECTIVES

To determine if performing an open laparoscopy after the diagnostic work-up of patients suspected of advanced ovarian cancer is accurate in predicting the resectability of disease.

SEARCH METHODS

We searched MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Register of Diagnostic Test Accuracy Studies, MEDION and ISI Web of Science to February 2013. Furthermore, we checked references of identified primary studies and review articles.

SELECTION CRITERIA

We included studies that evaluated the diagnostic accuracy of laparoscopy to determine the resectability of disease in patients who are suspected of advanced ovarian cancer and planned to receive primary debulking surgery.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the quality of included studies using QUADAS-2 and extracted data on study and patients' characteristics, index test, target condition and reference standard. Data for two-by-two tables were extracted and summarised graphically. Sensitivity and specificity and negative predictive values were calculated.

MAIN RESULTS

We included seven studies reporting on six cohorts. Between 27% to 64% of included patients per study were positive on laparoscopy (too extensive disease to warrant laparotomy) and between 36% to 73% were negative (disease suitable for debulking laparotomy). Only two studies avoided partial verification bias and provided data to calculate sensitivity and specificity, which did not justify meta-analysis. These two studies had a sensitivity of 0.70 (95% confidence interval (CI) 0.57 to 0.82) and 0.71 (95% CI 0.44 to 0.90); however, the specificity of both studies was 1.00 (95% CI 0.90 to 1.00). In these two studies there were no false positives, i.e. no patients for whom laparoscopy indicated that major surgery would not be successful and should be avoided, whereas, in reality the patient could be successfully operated upon. Negative predictive values (NPV), for those patients who were diagnosed with having not too extensive disease correctly identified were 0.75 (95% CI 0.55 to 0.86) and 0.96 (95% CI 0.56 to 0.99) due to a different prevalence. Although the studies did report sufficient data to calculate NPVs, we judged these estimates too heterogeneous to meta-analyse.Three studies described the development or validation of a prediction model with a clear cut-off for test positivity. Sensitivity and specificity of these prediction models were 0.30 to 0.70 and 0.89 to 1.00, respectively. However, one of these studies suffered from partial verification bias.

AUTHORS' CONCLUSIONS

Laparoscopy is a promising test, but the low number of studies and the differences between the included studies do not allow firm conclusions to be drawn from these data. Due to a difference in prevalence, there is a wide range in negative predictive values between studies. Two studies verified all patients. These imply a high specificity of laparoscopy in diagnosing resectability and have a good sensitivity. Both studies show that the use of criteria for unresectable disease will result in no patients inappropriately unexplored. However, there will still be patients undergoing unsuccessful primary laparotomy. Using a prediction model does not increase the sensitivity and will result in more unnecessarily explored patients, due to a lower specificity.

A novel melittin-MhIL-2 fusion protein inhibits the growth of human ovarian cancer SKOV3 cells in vitro and in vivo tumor growth

In the current study, we produced a novel fusion protein (melittin-mutant human interleukin 2, melittin-MhIL-2) comprising a mutant human interleukin 2 (Arg88/Ala125) genetically linked to melittin. The plasmid pET15b-melittin-MhIL-2 (Arg88/Ala125) was transformed into E. coli for protein expression. The expressed melittin-MhIL-2 protein was purified using a series of purification steps. The interleukin 2 (IL-2) activity of melittin-MhIL-2 fusion protein was compared with recombinant human interleukin 2 (rhIL-2) for its ability to induce CTLL-2 proliferation. Moreover, the fusion protein directly inhibits the growth of human ovarian cancer SKOV3 cells in vitro. In an in vivo initial experiment, the fusion protein inhibited tumor growth in ovarian cancer mice. In conclusion, we generated a novel melittin-MhIL-2 fusion protein that retained functional activity of IL-2 and melittin and inhibited tumor growth in vivo.

Anti-KDEL-coated nanoparticles: a promising tumor targeting approach for ovarian cancer?

The purpose of this study was to target ovarian cancer cells by coupling paclitaxel (Tx)-loaded nanoparticles (NPs-Tx) to antibodies against KDEL sequence, able to recognize GRP94 and GRP78 that are located at cell surface in cancer cells whereas they are in the endoplasmic reticulum in healthy cells. Tx-loaded poly (DL-lactic acid) nanoparticles coated with anti-KDEL antibodies (NPs-Tx-KDEL) were successfully prepared and characterized. Interaction between tumor cells and NPs-Tx or NPs-Tx-KDEL was observed by microscopy with fluorescently labeled NPs and the efficacy of the different formulations was compared by a viability assay. Particles functionalized with monoclonal antibodies (mAb) showed a higher binding to the cells even though the internalization rate appeared limited. The effect of NPs-Tx-KDEL on cell viability (proliferation) was compared to Tx, NPs, NPs-Tx, anti-KDEL mAb or anti-KDEL mAb in combination with NPs-Tx in Bg-1 ovarian cell line. Our data indicate that NPs-Tx-KDEL significantly increase sensitivity of Bg-1 cells to Tx compared to other treatments. This study confirms the interest of anti-cancer therapy by targeting cell surface GRP78 and GRP94 on cancer cells, and demonstrates the efficiency of coupling KDEL antibodies to NPs.

Therapeutic strategies in epithelial ovarian cancer

Ovarian cancer is the most lethal gynecologic malignancy. It appears that the vast majority of what seem to be primary epithelial ovarian and primary peritoneal carcinomas is, in fact, secondary from the fimbria, the most distal part of the fallopian tube.

Treatment of epithelial ovarian cancer is based on the combination of cytoreductive surgery and combination chemotherapy using taxane and platinum. Although clear cell type is categorized in indolent type, it is known to show relatively strong resistance to carboplatin and paclitaxel regimen and thus poor prognosis compared to serous adenocarcinoma, especially in advanced stages. Irinotecan plus cisplatin therapy may effective for the clear cell adenocarcinoma.

The larger expectation for improved prognosis in ovarian carcinoma is related to the use of the new biological agents. One of the most investigated and promising molecular targeted drugs in ovarian cancer is bevacizumab, a monoclonal antibody directed against VEGF. PARP inhibitor is another one. A few recent studies demonstrated positive results of bevacizumab on progression-free survival in ovarian cancer patients, however, investigation of molecular targeting drugs in patients with ovarian cancer are still underway.

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.

Protein kinase A activity and anchoring are required for ovarian cancer cell migration and invasion

Epithelial ovarian cancer (EOC) is the deadliest of the gynecological malignancies, due in part to its clinically occult metastasis. Therefore, understanding the mechanisms governing EOC dissemination and invasion may provide new targets for antimetastatic therapies or new methods for detection of metastatic disease. The cAMP-dependent protein kinase (PKA) is often dysregulated in EOC. Furthermore, PKA activity and subcellular localization by A-kinase anchoring proteins (AKAPs) are important regulators of cytoskeletal dynamics and cell migration. Thus, we sought to study the role of PKA and AKAP function in both EOC cell migration and invasion. Using the plasma membrane-directed PKA biosensor, pmAKAR3, and an improved migration/invasion assay, we show that PKA is activated at the leading edge of migrating SKOV-3 EOC cells, and that inhibition of PKA activity blocks SKOV-3 cell migration. Furthermore, we show that while the PKA activity within the leading edge of these cells is mediated by anchoring of type-II regulatory PKA subunits (RII), inhibition of anchoring of either RI or RII PKA subunits blocks cell migration. Importantly, we also show--for the first time--that PKA activity is up-regulated at the leading edge of SKOV-3 cells during invasion of a three-dimensional extracellular matrix and, as seen for migration, inhibition of either PKA activity or AKAP-mediated PKA anchoring blocks matrix invasion. These data are the first to demonstrate that the invasion of extracellular matrix by cancer cells elicits activation of PKA within the invasive leading edge and that both PKA activity and anchoring are required for matrix invasion. These observations suggest a role for PKA and AKAP activity in EOC metastasis.

Anti-cancer effect of bee venom toxin and melittin in ovarian cancer cells through induction of death receptors and inhibition of JAK2/STAT3 pathway

We investigated whether bee venom and melittin, a major component of bee venom, inhibit cell growth through enhancement of death receptor expressions in the human ovarian cancer cells, SKOV3 and PA-1. Bee venom (1-5 μg/ml) and melittin (0.5-2 μg/ml) inhibited the growth of SKOV3 and PA-1 ovarian cancer cells by the induction of apoptotic cell death in a dose dependent manner. Consistent with apoptotic cell death, expression of death receptor (DR) 3 and DR6 was increased in both cancer cells, but expression of DR4 was increased only in PA-1 cells. Expression of DR downstream pro-apoptotic proteins including caspase-3, 8, and Bax was concomitantly increased, but the phosphorylation of JAK2 and STAT3 and the expression of Bcl-2 were inhibited by treatment with bee venom and melittin in SKOV3 and PA-1 cells. Expression of cleaved caspase-3 was increased in SKOV3, but cleaved caspase-8 was increased in PA-1 cells. Moreover, deletion of DR3, DR4, and DR6 by small interfering RNA significantly reversed bee venom and melittin-induced cell growth inhibitory effect as well as down regulation of STAT3 by bee venom and melittin in SKOV3 and PA-1 ovarian cancer cell. These results suggest that bee venom and melittin induce apoptotic cell death in ovarian cancer cells through enhancement of DR3, DR4, and DR6 expression and inhibition of STAT3 pathway.