Treatment goals in ovarian cancer

NANOG regulates epithelial-mesenchymal transition and chemoresistance through activation of the STAT3 pathway in epithelial ovarian cancer

NANOG is a key transcription factor that is overexpressed and plays an important role in various cancers. Its overexpression is associated with highly tumorigenic, drug-resistant, and poor prognosis. However, the underlying mechanism of action of NANOG in ovarian cancer remains unclear. Epithelial-mesenchymal transition (EMT), which is a critical process in cancer invasion and metastasis, is also associated with drug resistance. We determined whether NANOG is associated with EMT and chemoresistance in epithelial ovarian cancer cells. NANOG expression was increased in epithelial ovarian cancer cells (HEY and SKOV3) compared with normal epithelial ovarian cells (Moody). Low expression of NANOG increased the expression of E-cadherin and decreased the expression of vimentin, β-catenin, and Snail. Furthermore, the cell migration and invasion abilities were decreased. The multidrug resistance genes MDR-1 and GST-π were also downregulated when NANOG was lowly expressed. The cells that were transfected with the si-NANOG plasmid were more sensitive to cisplatin compared with the cells that were transfected with empty vector. The data demonstrated that Stat3 was correlated with NANOG-mediated EMT and drug resistance. The silencing of Stat3 expression abrogated NANOG-mediated EMT changes and increased the sensitivity of the cells to chemotherapy. These results suggest that NANOG mediates EMT and drug resistance through activation of the Stat3 pathway in epithelial ovarian cancer.

Epithelial ovarian cancer stem-like cells expressing α-gal epitopes increase the immunogenicity of tumor associated antigens

Background

As ovarian cancer stem cells (CSCs) are responsible for tumor initiation, invasion, metastasis, and chemo-resistance, new stratagems that selectively target ovarian CSCs are critically significant. Our previous work have demonstrated that ovarian cancer spheroid cells are tumorigenic and chemo-resistant, and have the properties of ovarian CSCs. Herein, we hypothesized that expressing α-gal epitopes on ovarian spheroid cells may help eliminate CSCs and improve the outcome of therapeutic intervention for ovarian cancer patients.

Methods

Lentivirus-mediated transfer of a pig α(1,3)galactosyltransferase [α1,3GT] enzyme gene into human ovarian cell line SKOV3 cells formed α-gal epitope-expressing cells (SKOV3-gal cells), and then these cells were maintained in a serum-free culture system to form SKOV3-gal spheroid cells. Efficacy of this cell vaccine was demonstrated in α1,3GT knockout mice (α1,3GT KO mice).

Results

The antibody titers to α-gal epitopes measured by ELISA were significantly increased in α1,3GT KO mice after immunization with SKOV3-gal spheroid cells. Furthermore, compared with the non-immunized KO mice, the SKOV3 tumors grafted under renal capsules of KO mice immunized with SKOV3-gal spheroid cells grew slower and began to shrink on day 12. Western blot analysis also showed that immunized KO mice can produce effective antibody against certain tumor associated antigens (TAAs) derived from both SKOV3 cells and SKOV3 spheroid cells. The TAAs were further investigated by mass spectrometry and RNA interference (RNAi) technology. The results suggested that antibodies responding to protein c-erbB-2 may be raised in the sera of the mice after immunization with SKOV3-gal spheroid cells. Ultimately, vaccination with SKOV3-gal spheroid cells induced more CD3 + CD4 + T cells in the spleen of immunized mice than non-immunized KO mice.

Conclusions

The results suggest that vaccination using ovarian cancer stem-like cells engineered to express α-gal epitopes may be a novel strategy for treatment of ovarian cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1973-7) contains supplementary material, which is available to authorized users.

Evolution of management in peritoneal surface malignancies

Management of peritoneal surface malignancies has gradually evolved by the introduction of cytoreductive surgery in combination with intraperitoneal chemotherapy applications. Recently, peritoneal metastases of intraabdominal solid organ tumors and primary peritoneal malignancies such as peritoneal mesothelioma are being treated with this new approach. Selection criteria are important to reduce morbidity and mortality rates of patients who will experience minimal or no benefit from these combined treatment modalities. Management of peritoneal surface malignancies with this current trend is presented in this review.

Hepatocyte growth factor secreted by ovarian cancer cells stimulates peritoneal implantation via the mesothelial-mesenchymal transition of the peritoneum

OBJECTIVE

A current working model for the metastatic process of ovarian carcinoma suggests that cancer cells are shed from the ovarian tumor into the peritoneal cavity and attach to the layer of mesothelial cells that line the inner surface of the peritoneum, and several studies suggest that hepatocyte growth factor (HGF) plays an important role in the dissemination of ovarian cancer. Our objectives were to evaluate the HGF expression of ovarian cancer using clinical data and assess the effect of HGF secreted from human ovarian cancer cells to human mesothelial cells.

METHODS

HGF expression was immunohistochemically evaluated in 165 epithelial ovarian cancer patients arranged as tissue microarrays. HGF expression in four ovarian cancer cell lines was evaluated by using semi-quantitative polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay. The effect of ovarian cancer cell derived HGF to the human mesothelial cells was assessed by using morphologic analysis, Western blotting and cell invasion assay. The effect of HGF on ovarian cancer metastasis was assessed by using in vivo experimental model.

RESULTS

The clinical data showed a significantly high correlation between the HGF expression and the cancer stage. The in vivo and in vitro experimental models revealed that HGF secreted by ovarian cancer cells induces the mesothelial-to-mesenchymal transition and stimulates the invasion of mesothelial cells. Furthermore, manipulating the HGF activity affected the degree of dissemination and ascite formation.

CONCLUSIONS

We demonstrated that HGF secreted by ovarian cancer cells plays an important role in cancer peritoneal implantation.

Regional hyperthermia of the abdomen, a pilot study towards the treatment of peritoneal carcinomatosis

BACKGROUND

Peritoneal carcinomatosis occurs in different cancer subtypes and is associated with a dismal prognosis. Some doubts remain whether the whole abdomen can be treated by regional hyperthermia, therefore we analyzed feasibility conducting a pilot study.

METHODS

A simulation of the abdominopelvic heat distribution in 11 patients with peritoneal carcinomatosis was done using the HyperPlan software and the SIGMA-60 and SIGMA-Eye applicators. Tissue-specific region-related electrical and thermal parameters were used to solve the Maxwell's equations and the bioheat-transfer equation. Three-dimensional specific absorption rate (SAR) distributions and, additionally, estimated region-related perfusion rates were used to solve the bioheat-transfer equation. The predicted SAR and temperature distributions were compared with minimally invasive measurements in pelvic reference points.

RESULTS

In 11 patients (7 of them treated in the SIGMA-60 and 4 in the SIGMA-Eye applicator) the measured treatment variables (SAR, temperatures in the pelvic reference points) indicated that the heated volumes were higher for the SIGMA-Eye applicator. The mean computed abdominal SARs were less for the SIGMA-Eye (33 versus 44 W/kg). Nevertheless, the temperature distributions in the abdomen (peritoneal cavity) were more homogeneous in the SIGMA-Eye applicator as compared to the SIGMA-60 as indicated by higher values of T90 (mean 40.2 versus 38.2 °C) and T50 (mean 41.1 versus 40.2 °C), while the maximum temperatures were similar (in the range 41 to 43 °C). Even though the mean abdominal SAR was lower in the SIGMA-Eye, the heat distribution covered a larger volume of the abdomen (in particular the upper abdomen). For the SIGMA-60 applicator the achieved T90 appeared to be limited between 41 and 42 °C, for the SIGMA Eye applicator more effective T90 in the range 42 to 43 °C were obtained.

CONCLUSION

Our results suggest that an adequate heating of the abdomen and therefore abdominal regional hyperthermia in PC patients appears feasible. The SIGMA-Eye applicator appears to be superior compared to the SIGMA-60 applicator for abdominal hyperthermia.

Role of imaging in the pretreatment evaluation of common gynecological cancers

Different treatment options are available for patients with gynecological cancers. Imaging plays an important role in assessment of patients with common cancers involving uterine body, cervix and ovaries, from detection to evaluation of the extent of disease. The purpose of this review is to highlight the role of cross-sectional imaging techniques in treatment stratification and overall management of patients with endometrial, cervical and ovarian cancers. Several imaging techniques used are described, including ultrasound, computed tomography (CT), MRI and PET/CT. Specific imaging appearances of the most common uterine, cervical and ovarian cancers are discussed. Imaging findings corresponding to the 2009 revised International Federation of Gynecology and Obstetrics (FIGO) staging of gynecologic malignancies are also described. In the multidisciplinary evaluation of patients with gynecologic malignancies, the role of the radiologist has become central for accurate diagnosis and evaluation of extent of disease to achieve better treatment selection and planning.

Nanodelivery of gambogic acid by functionalized graphene enhances inhibition of cell proliferation and induces G0/G1 cell cycle arrest in cervical, ovarian, and prostate cancer cells

Graphene was used to deliver gambogic acid to cervical, ovarian, and prostate cancer cells and the complex was shown to be more effective at inhibiting cell proliferation, initiating cell cycle arrest and inducing apoptosis compared to the drug alone.

Carboplatin and taxol resistance develops more rapidly in functional BRCA1 compared to dysfunctional BRCA1 ovarian cancer cells

A major risk factor for ovarian cancer is germline mutations of BRCA1/2. It has been found that (80%) of cellular models with acquired platinum or taxane resistance display an inverse resistance relationship, that is collateral sensitivity to the other agent. We used a clinically relevant comparative selection strategy to develop novel chemoresistant cell lines which aim to investigate the mechanisms of resistance that arise from different exposures of carboplatin and taxol on cells having BRCA1 function (UPN251) or dysfunction (OVCAR8). Resistance to carboplatin and taxol developed quicker and more stably in UPN251 (BRCA1-wildtype) compared to OVCAR8 (BRCA1-methylated). Alternating carboplatin and taxol treatment delayed but did not prevent resistance development when compared to single-agent administration. Interestingly, the sequence of drug exposure influenced the resistance mechanism produced. UPN251-6CALT (carboplatin first) and UPN251-6TALT (taxol first) have different profiles of cross resistance. UPN251-6CALT displays significant resistance to CuSO4 (2.3-fold, p=0.004) while UPN251-6TALT shows significant sensitivity to oxaliplatin (0.6-fold, p=0.01). P-glycoprotein is the main mechanism of taxol resistance found in the UPN251 taxane-resistant sublines. UPN251 cells increase cellular glutathione levels (3.0-fold, p=0.02) in response to carboplatin treatment. However, increased glutathione is not maintained in the carboplatin-resistant sublines. UPN251-7C and UPN251-6CALT are low-level resistant to CuSO4 suggesting alterations in copper metabolism. However, none of the UPN251 sublines have alterations in the protein expression of ATP7A or CTR1. The protein expression of BRCA1 and MRP2 is unchanged in the UPN251 sublines. The UPN251 sublines remain sensitive to parp inhibitors veliparib and CEP8983 suggesting that these agents are candidates for the treatment of platinum/taxane resistant ovarian cancer patients.

A qualitative study of ovarian cancer survivors' perceptions of endpoints and goals of care

OBJECTIVES

A survey of the Ovarian Cancer National Alliance revealed a communication gap between physicians and survivors. This qualitative study explored the space between perceptions in hopes of better defining treatment endpoints meaningful to treating physicians and their patients.

METHODS

A focus group of ovarian cancer survivors (n=22) was assembled via the survivor support network SHARE. A physician-guided session explored expectations of treatment, perceived outcomes, toxicity thresholds and decision making. The session was recorded, transcribed and coded. Common themes were identified and used to perform intra-case analysis by two independent reviewers.

RESULTS

The main themes identified were barriers to communication, importance of frequent communication between patient and physician regarding goals, and expectations of treatment changing with position along the treatment continuum. One hundred percent of participants identified communication with their physician as an essential element in determining treatment course. However, only 14% reported having a discussion about goals, values and perceptions with their physician preceding treatment decisions. Participants reported that the terms progression free and overall survival held minimal significance for them and instead they preferred an individualized approach to care focusing on quality of life. Many women underreported side effects with reasons ranging from fear of dose reductions and additional tests to forgetting about symptoms due to anxiety.

CONCLUSIONS

An objective measure of treatment success meaningful to survivors, physicians and regulators is, at present, elusive and may not exist. Ideally, future trial design would place equal weight on quantitative and qualitative measures and include information about goals of treatment.

Upregulation of Limk1 caused by microRNA-138 loss aggravates the metastasis of ovarian cancer by activation of Limk1/cofilin signaling

LIM kinase 1 (Limk1) is associated with cell prolife-ration and metastasis and its dysregulated expression has been observed in many types of cancer. The present study aimed to examine the role of Limk1 in the development of ovarian cancer, as well as the underlying molecular mechanism involved. The results showed that increased Limk1 and decreased miR-138 expression co-existed in ovarian cancer. Furthermore, knockout of Limk1 or the overexpression of miR-138 resulted in reduced cell invasion and migration, while silencing of miR-138 led to enhancement of the invasion and migration of ovarian cancer cells. Cell growth was inhibited by the overexpression of miR-138, although not by the knockout of Limk1. miR-138 directly targeted Limk1 and inhibited ovarian cancer cell growth by PCNA and Bcl-2. Moreover, Limk1/cofilin/p-cofilin is likely a critical signaling pathway involving in miR-138 modulation of ovarian cancer cell metastasis. The results provide evidence supporting miR-138/Limk1 as a novel diagnostic or therapeutic target for ovarian cancer.

Metformin combined with p38 MAPK inhibitor improves cisplatin sensitivity in cisplatin‑resistant ovarian cancer

The aim of the present study was to determine the effects of metformin, combined with a p38 mitogen‑activated protein kinase (MAPK) inhibitor, on the sensitivity of cisplatin‑resistant ovarian cancer to cisplatin. The expression and distribution of phosphorylated p38 MAPK (P‑p38 MAPK) was confirmed in drug‑resistant and primary ovarian cancer tissues by immunohistochemistry and western blotting. A bromodeoxyuridine ELISA kit was used to analyze the effects of metformin, SB203580, a p38 MAPK inhibitor, and metformin combined with SB203580, on the cell proliferation of SKOV3/DDP cisplatin‑resistant ovarian cancer cells. The protein expression of P‑p38 MAPK was significantly higher in cisplatin‑resistant ovarian cancer, as compared with the primary ovarian cancer tissues. Metformin combined with SB203580 significantly enhanced the sensitivity of SKOV3/DDP cells to cisplatin. In conclusion, the p38 MAPK signaling pathway may be associated with cisplatin‑resistant ovarian cancer. Metformin, combined with the p38 MAPK inhibitor, significantly increased the sensitivity of SKOV3/DDP cells to cisplatin treatment.

The EMT (epithelial-mesenchymal-transition)-related protein expression indicates the metastatic status and prognosis in patients with ovarian cancer

Objectives

The epithelial-mesenchymal-transition (EMT) is an important step in the invasion and metastasis of cancer. A critical molecular feature of this process is the downregulation of the E-cadherin expression, which is primarily controlled by Snail-related zinc-finger transcription factors. The aim of this study was to evaluate the prognostic impact of the expression of EMT-related proteins (E-cadherin and Snail) in patients with ovarian cancer.

Methods

An immunohistochemical analysis was conducted using tissue microarray samples of 174 primary tumors and 34 metastases of ovarian carcinoma, and the relationships between the protein expression, clinicopathological features and outcomes were investigated.

Results

A reduced E-cadherin expression was observed in 36.8% of the primary tumors and 30.4%, 35.7%, 37.7% and 52.7% of the stage I, II, III and IV tumors, respectively. The nuclear expression of Snail was positive in 33.9% of the primary tumors. The rate of an EMT-positive status, as represented by both a reduced E-cadherin expression and a nuclear expression of Snail, was significantly higher in the patients with peritoneal dissemination than in those without (p < 0.05). The EMT status was significantly associated with both the progression-free survival and overall survival (p <0.01). A multivariate analysis showed an EMT-positive status to be a significant predictor of both the progression-free survival (p < 0.05) and overall survival (P < 0.01).

Conclusions

These data indicate that the EMT status is significantly associated with peritoneal metastasis and both the progression-free survival and overall survival in patients with ovarian cancer. Therefore, clarifying and controlling EMT signaling is a promising approach to molecular targeted therapy for ovarian cancer.

Oncogenic Fli-1 is a potential prognostic marker for the progression of epithelial ovarian cancer

Background

Ovarian cancer is the most lethal gynecologic malignancy, but its etiology remains poorly understood. This study investigated the role of Fli-1 in ovarian carcinogenesis and disease survival.

Methods

Fli-1 protein expression was evaluated by immunohistochemistry in 104 primary epithelial ovarian cancer (EOC) patients with known follow-up data and 20 controls. Correlation between Fli-1 expression and clinical characteristics was evaluated with the logistic regression. Kaplan Meier analysis was used to assess the impact of Fli-1 expression on overall survival (OS) and disease-free survival (DFS). Cell proliferation and migration assay were used to explore the function of Fli-1 in ovarian cancer cells.

Results

Fli-1 was expressed in 74% cases and up-regulated in EOC tissues compared with normal control tissues (p< 0.05). The high expression of Fli-1 was significantly associated with advanced tumor stage, positive lymph nodal involvement, and poor OS and DFS (p< 0.05). Further analysis showed Fli-1 is an independent prognostic factor for OS and DFS. Down-regulation of Fli-1 inhibited cell proliferation but did not affect cell migration in SKOV3 cells.

Conclusions

This study revealed that Fli-1 played an essential role in the development and progression of ovarian cancers. Its overexpression is intimately related to malignant phenotypes and poor clinical outcome, suggesting that Fli-1 is a potential prognostic marker and therapeutic molecular target in ovarian cancer.

SDF-1/CXCR7 axis enhances ovarian cancer cell invasion by MMP-9 expression through p38 MAPK pathway

Ovarian cancer is an aggressive gynecological malignancy with high metastatic potential. Recently, the CXC receptor (CXCR7) has been identified as a new receptor for stromal-derived factor-1 (SDF-1), and exerts important roles in cancer development. However, its effect on ovarian cancer and the underlying mechanism remain unknown. In this study, we detected abundant CXCR7 expression in ovarian cancer tissues and cells. Moreover, SDF-1 induced dramatically upregulation of CXCR7 mRNA and protein levels, indicating that the SDF-1/CXCR7 axis existed in ovarian cancer. Further analysis confirmed that SDF-1 enhanced cell adhesion and subsequent invasion, which were significantly attenuated when pretreated with CXCR7 small interference RNA (siRNA), indicating the critical function of SDF-1/CXCR7 in cell invasion. Further mechanistic analysis indicated that SDF-1/CXCR7 enhanced cell invasion by matrix metalloproteinase (MMP)-9, as pretreatment with MMP-9 siRNA significantly abrogated a number of invading cells. Additionally, SDF-1/CXCR7 induced phosphorylation of the p38 MAPK pathway, which was accounted for MMP-9 expression as preconditioning with the p38 MAPK inhibitor SB203580 obviously decreased MMP-9 expression. Together, our data implied that SDF-1/CXCR7 enhanced ovarian cancer cell invasion by MMP-9 expression through the p38 MAPK pathway. Thus, these findings confirmed the critical role of SDF-1/CXCR7 during the pathological processes of ovarian cancer and supported its potential targets for further development of antiovarian cancer therapy.

Intraperitoneal chemotherapy against peritoneal carcinomatosis: current status and future perspective

Peritoneal carcinomatosis (PC), caused by advanced abdominal malignancies, such as those of the ovarian and gastrointestinal tracts, has an extremely poor prognosis. Intraperitoneal (IP) chemotherapy has been clinically applied for several decades, but its clinical efficacy has not been fully determined. An accumulating body of evidence suggests that cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) is the optimal treatment for selected patients with ovarian and colorectal cancers with PC. Recent studies suggest that IP administration of taxane with systemic chemotherapy in a neoadjuvant setting improves patient survival in gastric cancer with PC. The pharmacokinetics of IP-administered drugs should be primarily considered in order to optimize IP chemotherapy. Therefore, the development of specific IP drugs using newly emerging molecular targeted reagents or new drug delivery systems, such as nanomedicine or controlled absorption/release methods, is essential to improve the efficacy of IP chemotherapy.

KLF5 strengthens drug resistance of ovarian cancer stem-like cells by regulating survivin expression

OBJECTIVES

Ovarian cancer stem-like cells (CSCs), which can form non-adherent sphere cells in a stem-cell selection culture system, exhibit stemness and drug resistance to chemotherapeutics, which are properties not observed in differentiated cells. Recent studies have demonstrated that Kruppel-like factor 5 (KLF5) is involved in cell proliferation and mediates cell survival and tumourigenesis. Here, we investigated the role of KLF5 and its downstream target survivin, in strengthening drug resistance of ovarian CSCs.

MATERIALS AND METHODS

Ovarian cancer cell line SKOV3 was cultured under serum-free conditions and differentiating conditions to promote formation of sphere cells and differentiated cells, respectively. siRNA-KLF5 was used to knock down KLF5, and survivin expression vector was used to overexpress survivin. Cells were further analysed by qPCR, immunofluorescence staining and western blotting. Chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA) were performed to investigate the relationship between KLF5 and survivin expression. Drug resistance was examined by MTT and apoptosis assays.

RESULTS

KLF5 was highly expressed in the ovarian cancer cell line SKOV3 sphere cells, accompanied by elevated survivin expression. Silencing KLF5 by small interfering RNA in sphere cells down-regulated survivin expression, which also sensitized the sphere cells to apoptosis induced by chemotherapeutic drugs (cisplatin or paclitaxel). Furthermore, ChIP assay, survivin overexpression and EMSA results indicated that KLF5 controlled survivin expression by directly binding the surivin promoter in the cells.

CONCLUSIONS

The KLF5-mediated signalling pathway is a potential target for elimination of ovarian CSCs.

Local control and prognostic significance of transarterial treatment for limited recurrence of ovarian cancer as third-line and beyond therapy

BACKGROUND

We aimed to retrospectively evaluate the safety and efficacy of transarterial treatment for the recurrence of ovarian cancer, limited to one or two gross regions, in a palliative setting as third-line and beyond therapy.

METHODS

Twenty-six consecutive patients were enrolled to undergo transarterial treatment of target lesions that were life-threatening or influenced their quality of life. Transarterial infusion via each feeding artery using 20-40 mg cisplatin and 20-40 mg docetaxel per patient was repeated every 4-6 weeks. Superabsorbent polymer microspheres were added for embolization after drug infusion, especially in hepatic or pelvic treatments. Univariate and multivariate Cox's proportional hazards models were used to assess the correlations between overall survival and individual parameters.

RESULTS

A total of 63 feeding arteries (median 2 per patient; range 1-5) were treated for 36 target sites (liver, 12; pelvis, 8; abdominal cavity, 7; lymph node, 3; other, 6) at the initial treatment. Of the 128 total sessions, the only grade 3/4 toxicity was neutropenia (3.8 %). The target lesion response rate by RECIST ver.1.1 was 50.0 % (11.5 % complete response; 38.5 % partial response). After a median follow-up of 30 months, the median overall survival was 16 months. Among 10 tumor-associated symptomatic patients, 7 showed symptom improvement. Multivariate analyses shows that the only independent prognostic factor was target lesion response (hazard ratio 18.7; 95 % CI 1.9-183.4; p = 0.01).

CONCLUSIONS

Transarterial treatment for ovarian cancer achieves a high local response and good symptom control, and significantly contributes to survival for patients with local control after multiple relapses.

Ovarian cancer stem cell-specific gene expression profiling and targeted drug prescreening

Cancer stem cells, with unlimited self-renewal potential and other stem cell characteristics, occur in several types of cancer, including ovarian cancer (OvC). Although CSCs can cause tumor initiation, malignant proliferation, relapse and multi-drug resistance, ways to eliminate them remain unknown. In the present study, we compared ovarian cancer stem cell (OVCSC) expression profiles in normal ovarian surface epithelium and ovarian cells from patients with advanced disease to identify key pathways and specific molecular signatures involved in OVC progression and to prescreen candidate small-molecule compounds with anti-OVCSC activity. Comparison of genome-wide expression profiles of OvC stemness groups with non-stemness controls revealed 6495, 1347 and 509 differentially expressed genes in SDC, SP1 and SP2 groups, respectively, with a cut-off of fold-change set at >1.5 and P<0.05. NAB1 and NPIPL1 were commonly upregulated whereas PROS1, GREB1, KLF9 and MTUS1 were commonly downregulated in all 3 groups. Most differentially expressed genes consistently clustered with molecular functions such as protein receptor binding, kinase activity and chemo-repellent activity. These genes regulate cellular components such as centrosome, plasma membrane receptors, and basal lamina, and may participate in biological processes such as cell cycle regulation, chemoresistance and stemness induction. Key Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as ECM receptor, ErbB signaling, endocytosis and adherens junction pathways were enriched. Gene co-expression extrapolation screening by the Connectivity Map revealed several small-molecule compounds (such as SC-560, disulfiram, thapsigargin, esculetin and cinchonine) with potential anti-OVCSC properties targeting OVCSC signature genes. We identified several key CSC features and specific regulation networks in OVCSCs and predicted several small molecules with potential anti-OVCSC pharmacological properties, which may aid the development of OVCSC-specific drugs.

Gemcitabine plus carboplatin in platinum-sensitive recurrent ovarian carcinoma

Although the general intent of treatment for patients with recurrent ovarian cancer is palliative, and cure does not seem to be a realistic objective in this setting, median overall survival is greater than 12 months in platinum-sensitive recurrent ovarian cancer. Patients with ovarian cancer can now expect that the time from first relapse of their disease to death will be longer than the period from diagnosis to that first relapse. There is current evidence from prospective randomized trials that carboplatin combined with either paclitaxel or gemcitabine confers a progression-free survival advantage over platinum monotherapy for patients with platinum-sensitive relapsed ovarian cancer. Since the efficacy of paclitaxel/platinum and gemcitabine/carboplatin regimens appears to be comparable based on similar progression-free survival (both combinations confer a 3-month advantage), toxicity profiles should be taken into account when deciding on the combination to be used. The gemcitabine/carboplatin combination should be preferred in patients with underlying peripheral neuropathy. Since alopecia associated with paclitaxel can diminish the overall quality of life, the gemcitabine plus carboplatin combination may be preferable for patients in whom alopecia is a major consideration. This review provides an update on the role of the gemcitabine/carboplatin combination in platinum-sensitive recurrent ovarian cancer.

Hypomethylation signature of tumor-initiating cells predicts poor prognosis of ovarian cancer patients

DNA methylation contributes to tumor formation, development and metastasis. Epigenetic dysregulation of stem cells is thought to predispose to malignant development. The clinical significance of DNA methylation in ovarian tumor-initiating cells (OTICs) remains unexplored. We analyzed the methylomic profiles of OTICs (CP70sps) and their derived progeny using a human methylation array. qRT-PCR, quantitative methylation-specific PCR (qMSP) and pyrosequencing were used to verify gene expression and DNA methylation in cancer cell lines. The methylation status of genes was validated quantitatively in cancer tissues and correlated with clinicopathological factors. ATG4A and HIST1H2BN were hypomethylated in OTICs. Methylation analysis of ATG4A and HIST1H2BN by qMSP in 168 tissue samples from patients with ovarian cancer showed that HIST1H2BN methylation was a significant and independent predictor of progression-free survival (PFS) and overall survival (OS). Multivariate Cox regression analysis showed that patients with a low level of HIST1H2BN methylation had poor PFS (hazard ratio (HR), 4.5; 95% confidence interval (CI), 1.4-14.8) and OS (HR, 4.3; 95% CI, 1.3-14.0). Hypomethylation of both ATG4A and HIST1H2BN predicted a poor PFS (HR, 1.8; 95% CI, 1.0-3.6; median, 21 months) and OS (HR, 1.7; 95% CI, 1.0-3.0; median, 40 months). In an independent cohort of ovarian tumors, hypomethylation predicted early disease recurrence (HR, 1.7; 95% CI, 1.1-2.5) and death (HR, 1.4; 95% CI, 1.0-1.9). The demonstration that expression of ATG4A in cells increased their stem properties provided an indication of its biological function. Hypomethylation of ATG4A and HIST1H2BN in OTICs predicts a poor prognosis for ovarian cancer patients.

Genetic variants in matrix metalloproteinase genes as disposition factors for ovarian cancer risk, survival, and clinical outcome

Ovarian cancer is one of the leading female cancers in the United States. Challenges remain in early diagnosis of this deadly disease. Matrix metalloproteinases (MMPs) family genes are paradoxically involved in cancer promotion and suppression. We hypothesize that genetic variants in MMP genes are associated with ovarian cancer development, so they could be potential markers for ovarian cancer diagnosis and prognosis. In this study of 417 ovarian cancer cases and 417 healthy controls, we genotyped a comprehensive panel of 266 single nucleotide polymorphisms (SNPs) in 23 MMP genes and analysed their associations with ovarian cancer risk, overall survival and treatment response in ovarian cancer cases who received platinum-based chemotherapy with surgery. In the analysis on 339 Caucasian cases and 349 Caucasian controls, 4 SNPs were significantly associated with cancer risk. The most significant association was observed for rs2292730 (OR = 2.03, 95% CI = 1.39-2.96, P = 0.0002). Classification and regression tree analysis identified four terminal nodes with differential risk of ovarian cancer. Thirty-four SNPs were significantly associated with overall survival and four of which showed significant association with response to chemotherapy. Unfavourable genotype analysis of top SNPs on overall risk of death showed significant gene-dosage effect, survival tree analysis differentiated patients into distinct risk groups based on their genetic profiles with median survival times (MSTs) ranging from 17.7 to 151.7 months. In conclusion, our results suggest that genetic variants in MMP pathway genes may modulate the risk and clinical outcomes of ovarian cancer, both individually and jointly.

Cytoreductive surgery in primary advanced epithelial ovarian cancer

Epithelial ovarian cancer is one of the most common malignancy and one of the principal causes of death among gynaecological neoplasm. The majority of patients (about 70%) present with an advanced International Federation of Gynaecology and Obstetrics stage disease. The current standard treatment for these patients consists of complete cytoreduction and combined systemic chemotherapy (CT). An increasing proportion of patients undergoing complete cytoreduction to no gross residual disease (RD) is associated with progressively longer overall survival. As a counterpart, some authors hypothesized the improving in survival could be due more to a less diffused initial disease than to an increase in surgical cytoreduction rate. Moreover the biology of the tumor plays an important role in survival benefit of surgery. It’s still undefined how the intrinsic features of the tumor make intra-abdominal implants easier to remove. Adjuvant and hyperthermic intraperitoneal CT could play a decisive role in the coming years as the completeness of macroscopic disease removal increases with advances in surgical techniques and technology. The introduction of neo-adjuvant CT moreover will play a decisive role in the next years Anyway cytoreduction with no macroscopic residual of disease should always be attempted. However the definition of RD is not universal. A unique and definitive definition is needed.

Over-expression of fibroblast activation protein alpha increases tumor growth in xenografts of ovarian cancer cells

Fibroblast activation protein alpha (FAPα) is a 95-kDa serine protease of post-prolyl peptidase family on cell surface. FAPα is widely expressed in tumor microenvironment. The wide spread association of FAPα expression with cancer suggests that it has important functions in the disease. However, the nature of FAPα's roles in cancer cell activity is not well-determined. It has been showed that FAPα silencing in SKOV3 cells induces ovarian tumors but significantly reduces tumor growth in a xenograft mouse model. To further determine the role of FAPα in epithelial ovarian cancer cells, SKOV3-FAPα and HO8910-FAPα cell lines, which over-expressed FAPα stably, were constructed and then their biological behaviors were investigated. It was found that FAPα promoted ovarian cancer cell proliferation, drug resistance, invasiveness, and migration in vitro. Immunochemistry assay showed that FAPα significantly facilitated tumor growth in xenograft tumor tissues. These results suggested that FAPα might directly promote tumor growth and invasiveness in ovarian cancer cells.

Imaging VCAM-1 as an indicator of treatment efficacy in metastatic ovarian cancer

The inability to successfully treat women with ovarian cancer is due in large part to the advanced stage of disease at diagnosis, the development of platinum resistance, and the lack of sensitive methods to monitor tumor progression and response to treatment. Vascular cell adhesion molecule-1 (VCAM-1) is expressed on the mesothelium of ovarian cancer patients. We investigated VCAM-1 expression as a marker of peritoneal metastasis and tumor response to platinum-based chemotherapy.

METHODS

Peritoneal or omental biopsies obtained from women diagnosed with stage I, stage II, or stage III/IV ovarian cancer were evaluated by immunohistochemistry. The effects of carboplatin on mesothelial VCAM-1 expression were determined in cultured cells by Western blot. Radiolabeled VCAM-1-specific peptide imaging probes and SPECT were used in a mouse model of ovarian cancer peritoneal metastasis to identify VCAM-1 as a viable imaging target.

RESULTS

VCAM-1 expression correlated with tumor stage. All specimens from stage I patients were negative, whereas 29% of stage II patients and 73% of stage III/IV patients were positive. Although most women with advanced stage disease expressed VCAM-1, the incidence of expression was reduced among women who received neoadjuvant chemotherapy, suggesting a role for chemotherapy in regulating VCAM-1 expression. Treatment of mesothelial cells in culture with carboplatin resulted in a transient decrease in VCAM-1 expression 4 h after treatment that returned to baseline within 16-24 h. In vivo imaging of VCAM-1 also demonstrated an acute decrease in expression 4 h after carboplatin administration that recovered within 48 h in mice harboring platinum-resistant tumors. Chronic VCAM-1 expression reflected the effect of platinum-based treatment on tumor burden. Specifically, carboplatin treatment of mice with platinum-sensitive tumors showed reduced VCAM-1 expression, which correlated with reduced tumor burden; mice with platinum-resistant tumors retained elevated VCAM-1 expression and tumor burden after treatment.

CONCLUSION

Clinically relevant VCAM-1-specific imaging probes identify VCAM-1 expression as an indicator of ovarian cancer peritoneal metastasis and therapeutic response to platinum-based agents. These observations support testing the utility of VCAM-1 imaging probes to monitor treatment response in ovarian cancer patients, thus providing the potential to improve management of women with this disease.

A two-stage, single-arm, phase II study of EGCG-enriched green tea drink as a maintenance therapy in women with advanced stage ovarian cancer

OBJECTIVES

A two-stage, single-arm, phase II study was conducted to assess the effectiveness and safety of an epigallocatechin gallate (EGCG)-enriched tea drink, the double-brewed green tea (DBGT), as a maintenance treatment in women with advanced stage serous or endometrioid ovarian cancer (clinicaltrials.gov, NCT00721890).

METHODS

Eligible women had FIGO stage III-IV serous or endometrioid ovarian cancer. They had to undergo complete response after debulking surgery followed by 6 to 8 cycles of platinum/taxane chemotherapy at the Centre Hospitalier Universitaire de Québec. They all had to drink the DBGT, 500 mL daily until recurrence or during a follow-up of 18 months. The primary endpoint was the absence of recurrence at 18 months. Statistical analyses were done according to the principle of intention to treat. Using a two-stage design, the first stage consisted of 16 enrolled patients. At the end of the follow-up, if 7 or fewer patients were free of recurrence, the trial stopped. Otherwise, accrual would continue to a total of 46 patients.

RESULTS

During the first stage of the study, only 5 of the 16 women remained free of recurrence 18 months after complete response. Accordingly, the clinical trial was terminated. Women's adherence to DBGT was high (median daily intake during intervention, 98.1%, interquartile range: 89.7-100%), but 6 women discontinued the intervention before the end of their follow-up. No severe toxicity was reported.

CONCLUSIONS

DBGT supplementation does not appear to be a promising maintenance intervention in women with advanced stage ovarian cancer after standard treatment.

Role of 18F-FDG PET/CT in diagnosing peritoneal carcinomatosis in the restaging of patient with ovarian cancer as compared to contrast enhanced CT and tumor marker Ca-125

OBJECTIVES

To investigate the role of whole-body fluorine-18-2-deoxy-2-fluoro-d-glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in the identification of peritoneal carcinomatosis in patients with ovarian cancer (OC).

MATERIAL AND METHODS

Seventy-nine patients with histologically proven stages III-IV OC who underwent (18)F-FDG PET/CT were studied retrospectively. We considered group A as 51 patients who also underwent computed-tomography with contrast-enhancement (CECT), and group B as 35 patients who had also been tested for biomarker Ca-125. Sensitivity, specificity, accuracy, positive predictive values (PPV) and negative predictive values (NPV) of (18)F-FDG PET/CT as compared to CECT and to Ca-125 were evaluated.

RESULTS

(18)F-FDG PET/CT' sensitivity, specificity, accuracy, PPV and NPV for all 79 patients were: 85%, 92.31%, 88.61%, 91.89% and 85.71%, respectively. (18)F-FDG PET/CT sensitivity in group A was 78.6%, while it was 53.6% for CECT. (18)F-FDG PET/CT specificity, calculated in the same group, was 91.3%, while that of CECT was 60.9% (statistically significant difference, McNemar 4, P=0.039). Accuracy was 84.3% and 56.9%, respectively. (18)F-FDG PET/CT' sensitivity in group B was 86.4%, while that of Ca-125 was 81.8% (no statistical difference, McNemar 0, P=1). (18)F-FDG PET/CT specificity in group B was 84.6% while that of Ca-125 was 38.5% (clear but not statistically significant difference, McNemar 3.12, P=0.070). Accuracy calculated in the same group was 85.7% for (18)F-FDG PET/CT and 65.7% for Ca-125.

CONCLUSION

(18)F-FDG PET/CT is a useful diagnostic tool when peritoneal biopsy cannot be performed and it can better select those who are candidates for adjuvant chemotherapy.

MicroRNAs as therapeutic targets in chemoresistance

Despite substantial progress in understanding the cancer signaling network, effective therapies remain scarce due to insufficient disruption of oncogenic pathways, drug resistance and drug-induced toxicity. New and more creative approaches are therefore required for the treatment of cancer. MicroRNAs (miRNAs) are a family of small noncoding RNAs that regulate gene expression by sequence-selective targeting of mRNAs, leading to a translational repression or mRNA degradation. Experimental evidence demonstrates that dysregulation of specific miRNAs leads to drug resistance in different cancers and correction of these miRNAs using miRNA mimics or antagomiRs can normalize the gene regulatory network and signaling pathways and sensitize cancerous cells to chemotherapy. Therefore, miRNA-based gene therapy provides an attractive anti-tumor approach for integrated cancer therapy. Here, we will discuss the involvement of microRNAs in chemotherapy resistance and focus on recent advancements in the development and delivery of miRNA-based cancer therapeutics.

Cost-effectiveness of trabectedin plus pegylated liposomal doxorubicin for the treatment of women with relapsed platinum-sensitive ovarian cancer in the UK: analysis based on the final survival data of the OVA-301 trial

OBJECTIVES

To estimate the cost-effectiveness of trabectedin plus pegylated liposomal doxorubicin (PLD) compared with PLD alone for the treatment of patients with relapsed platinum-sensitive ovarian cancer who are not expected to benefit from retreatment with platinum-based therapies based on the final survival data published in October 2012.

METHODS

A decision-analytic model estimated the cost per quality-adjusted life-year (QALY) gained for trabectedin plus PLD compared with PLD alone from the UK National Health Service and Personal Social Services perspective over a lifetime horizon. Mean progression-free survival and overall survival were calculated by using parametric survival distributions adjusted for imbalances discovered in the final survival data. Between-arm imbalances included the platinum-free interval, cancer antigen 125 (CA-125), and Eastern Cooperative Oncology Group performance score. Cost categories included drug, administration, medical management, and treatment of adverse events. Quality of life was measured by using the EuroQol five-dimensional questionnaire. Uncertainty was addressed by deterministic and probabilistic sensitivity analysis.

RESULTS

Over a lifetime horizon, trabectedin plus PLD increased mean progression-free survival by 3.0 months and overall survival by 9.7 months compared with PLD alone. The additional cost and QALYs of trabectedin plus PLD were £18,476 and 0.49, resulting in an incremental cost-effectiveness ratio of £38,026 per QALY. Sensitivity analyses showed that results were sensitive to platinum-free interval adjustment and the choice of survival distributions.

CONCLUSIONS

The analysis estimated a significant improvement in mean overall survival and incremental cost per QALY compared with that calculated in the original National Institute for Health and Clinical Excellence assessment, which was based on immature survival data.

Targeting CD133 in an in vivo ovarian cancer model reduces ovarian cancer progression

OBJECTIVES

While most women with ovarian cancer will achieve complete remission after treatment, the majority will relapse within two years, highlighting the need for novel therapies. Cancer stem cells (CSC) have been identified in ovarian cancer and most other carcinomas as a small population of cells that can self-renew. CSC are more chemoresistant and radio-resistant than the bulk tumor cells; it is likely that CSC are responsible for relapse, the major problem in cancer treatment. CD133 has emerged as one of the most promising markers for CSC in ovarian cancer. The hypothesis driving this study is that despite their low numbers in ovarian cancer tumors, CSC can be eradicated using CD133 targeted therapy and tumor growth can be inhibited.

METHODS

Ovarian cancer cell lines were evaluated using flow cytometry for expression of CD133. In vitro viability studies with an anti-CD133 targeted toxin were performed on one of the cell lines, NIH:OVCAR5. The drug was tested in vivo using a stably transfected luciferase-expressing NIH:OVCAR5 subline in nude mice, so that tumor growth could be monitored by digital imaging in real time.

RESULTS

Ovarian cancer cell lines showed 5.6% to 16.0% CD133 expression. dCD133KDEL inhibited the in vitro growth of NIH:OVCAR5 cells. Despite low numbers of CD133-expressing cells in the tumor population, intraperitoneal drug therapy caused a selective decrease in tumor progression in intraperitoneal NIH:OVCAR5-luc tumors.

CONCLUSIONS

Directly targeting CSC that are a major cause of drug resistant tumor relapse with an anti-CD133 targeted toxin shows promise for ovarian cancer therapy.

Ovarian cancer stem cells enrichment

The concept of cancer stem cells (CSCs) provides a new paradigm for understanding cancer biology. Cancer stem cells are defined as a minority of cancer cells with stem cell properties responsible for maintenance and growth of tumors. The targeting of CSCs is a potential therapeutic strategy to combat ovarian cancer. Ovarian epithelial cancer cells cultured in serum-free medium can form sphere cells. These sphere cells may be enriched for cancer stem cells (CSCs). The isolation of sphere cells from solid tumors is an important technique in studying cancer cell biology. Here we describe the isolation of sphere cells from primary ovarian cancer tissue, ascites fluid, and the cancer cell line SKOV3 with stem cell selection medium.

Genetic and epigenetic alterations of steroidogenic factor‑1 in ovarian tumors

Steroidogenic factor-1 (SF-1), the product of the NR5A1 gene, is an essential transcription factor that is known to regulate steroidogenesis in ovarian epithelia, including the synthesis of progesterone, a suppressor of ovarian cancer. Expression of the SF-1 protein, a potential ovarian tumor suppressor, has been demonstrated in normal OSE cells, but is lost in most ovarian tumors and ovarian tumor cell lines. We examined loss of heterozygosity (LOH) and promoter methylation as potential mechanisms that may explain the loss of SF-1 protein in ovarian tumor tissues. Genotyping of three NR5A1 SNPs in matched tumor/normal tissues identified LOH in 16/36 (44%) of the ovarian tumors successfully analyzed, and somatic mutations (gain of allele) in 10% of the tumors. Furthermore, a methylation-sensitive restriction enzyme method was used to demonstrate statistically significant (p<0.0001) increase in the frequency of NR5A1 gene methylation in ovarian tumors (36/46; 78%) versus normal ovaries (1/11; 9%). These data suggest that the SF-1 encoding gene exhibits frequent genetic (LOH/base substitution) and epigenetic (methylation) somatic alterations in ovarian tumors. These data also present novel molecular mechanisms that may explain the loss of SF-1 protein in ovarian tumors, and its potential role in ovarian carcinogenesis.

Intraperitoneal chemotherapy in ovarian cancer: a review of tolerance and efficacy

PURPOSE

TO REVIEW THE TWO MAIN APPROACHES OF INTRAPERITONEAL (IP) CHEMOTHERAPY DELIVERY IN OVARIAN CANCER: postoperative adjuvant IP chemotherapy after cytoreductive surgery (CRS) and intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

A literature search was conducted to identify studies that employed postoperative adjuvant IP chemotherapy after CRS or combined CRS and intraoperative HIPEC in patients with ovarian cancer. Data of interest included chemotherapy protocol, morbidity and mortality, and survival data.

RESULTS

Three large randomized controlled trials comprising 707 patients with advanced ovarian cancer who received postoperative adjuvant IP chemotherapy were reviewed. Morbidity rate ranged from 56% to 94% in IP chemotherapy, and mortality rate ranged from 1% to 2%. Median disease-free survival ranged from 24 to 28 months, and overall survival ranged from 49 to 66 months. Planned chemotherapy completion rates ranged from 42% to 71%. Twenty-four nonrandomized studies that reported HIPEC comprised 1167 patients with both advanced and recurrent ovarian cancer. In patients with advanced ovarian cancer, mortality ranged from 0% to 5%, minor morbidity ranged from 16% to 90%, and major morbidity ranged from 0% to 40%. Median disease-free survival ranged from 13 to 56 months, and overall survival ranged from 14 to 64 months. Survival at 5 years ranged from 35% to 70%. In patients with recurrent ovarian cancer, the mortality rate ranged from 0% to 10%, minor morbidity ranged from 7% to 90%, and major morbidity ranged from 0% to 49%. Median disease-free survival ranged from 13 to 24 months and overall survival from 23 to 49 months. Survival at 5 years ranged from 12% to 54%.

CONCLUSION

There is level-one evidence suggesting the benefit of postoperative adjuvant intraperitoneal chemotherapy for patients with advanced ovarian cancer after cytoreductive surgery, albeit catheter-related complications resulted after treatment discontinuation. Studies report the use of HIPEC predominantly in the setting of recurrent disease and have demonstrated encouraging results, which merits further investigation in future clinical trials.

Ovarian cancer in elderly patients: a difference in treatment based on age?

PURPOSE

The aim of this study was to examine if treatment strategies differ by age in the elderly population with ovarian cancer in daily clinical practice.

METHODS

A retrospective analysis of elderly patients with ovarian cancer who were referred to our institution between January 2007 and August 2010 was done. A univariate analysis for overall survival was estimated according to the Kaplan-Meier method, censoring surviving patients at the time of last follow-up.

RESULTS

We evaluated 32 elderly patients: 17 "young-old" patients (65-74 years old), 14 "old-old" patients (75-84 years old) and 1 "oldest-old" patient (≥85 years old). At last follow-up, 20 patients (62.5%) were alive and 12 patients (37.5%) were deceased. Median time follow-up was 18.52 months. Median overall survival was 19.05 months. Median age was 73.50 years. In the subgroup of "young-old" patients, there were less "high malignant potential" (64.3 vs. 70.0%) and grade 3 ovarian cancers (84.6 vs. 90.0%), less advanced stages (III-IV: 64.7 vs. 86.7%), higher number of optimal surgical procedures (50.0 vs. 30.0%) and more frequent use of chemotherapy (82.4 vs. 66.7%). Single agent carboplatin was administered in 81.8 vs. 77.8% of "young-old" and "old-oldest old" patients, and average number of lines was 2 vs. 1. Other characteristics were similar in the two subgroups ("young-old" vs. "old-oldest old" patients). By the univariate analysis, there was no statistical significance difference in overall survival (p=0.393) between the two subgroups, with only a positive trend for young-old patients.

CONCLUSIONS

In old- and oldest-old patients, the characteristics of disease are worse and optimal treatment strategy is less frequently applied. The management of patients by multidisciplinary team is needed and it could better individualize and apply the optimal treatment approach.

The relationship between cisplatin resistance and histone deacetylase isoform overexpression in epithelial ovarian cancer cell lines

Objective

To investigate the relationship between cisplatin resistance and histone deacetylase (HDAC) isoform overexpression in ovarian cancer cell lines.

Methods

Expression of four HDAC isoforms (HDAC 1, 2, 3, and 4) in two ovarian cancer cell lines, SKOV3 and OVCAR3, exposed to various concentrations of cisplatin was examined by western blot analyses. Cells were transfected with plasmid DNA of each HDAC. The overexpression of protein and mRNA of each HDAC was confirmed by western blot and reverse transcriptase-polymerase chain reaction analyses, respectively. The cell viability of the SKOV3 and OVCAR3 cells transfected with HDAC plasmid DNA was measured using the cell counting kit-8 assay after treatment with cisplatin.

Results

The 50% inhibitory concentration of the SKOV3 and OVCAR3 cells can be determined 15-24 hours after treatment with 15 µg/mL cisplatin. The expression level of acetylated histone 3 protein in SKOV3 cells increased after exposure to cisplatin. Compared with control cells at 24 hours after cisplatin exposure, the viability of SKOV3 cells overexpressing HDAC 1 and 3 increased by 15% and 13% (p<0.05), respectively. On the other hand, OVCAR3 cells that overexpressed HDAC 2 and 4 exhibited increased cell viability by 23% and 20% (p<0.05), respectively, compared with control cells 24 hours after exposure to cisplatin.

Conclusion

In SKOV3 and OVCAR3 epithelial ovarian cancer cell lines, the correlation between HDAC overexpression and cisplatin resistance was confirmed. However, the specific HDAC isoform associated with resistance to cisplatin varied depending on the ovarian cancer cell line. These results may suggest that each HDAC isoform conveys cisplatin resistance via different mechanisms.

The insulin-like growth factor system in cancer

Insulin-like growth factor (IGF) plays an important role in tissue growth and development. Several studies have demonstrated the association between circulating levels of IGF-1 and -2 and cancer risk, and the IGF system has been implicated in the oncogenesis of essentially all solid and hematologic malignancies. The optimal strategy for targeting IGF signaling in patients with cancer is not clear. The modest benefits reported thus far underscore the need for a better understanding of IGF signaling, which would enable clinicians to identify the subset of patients with the greatest likelihood of attaining benefit from this targeted approach.

Reproductive effects of a pegylated curcumin

Curcumin, a polyphenol derived from the rhizome turmeric, has potential as an anticancer agent. We synthesized an amphipathic/surfactant pegylated curcumin (curcumin-PEG) designed for parenteral administration. Objectives of these investigations were to assess side-effects of a therapeutic regimen of curcumin-PEG in a preclinical model. Intraperitoneal (ip) tumor burdens were reduced in athymic female mice grafted with human SKOV-3 ovarian adenocarcinoma cells and injected intravenously (iv) with curcumin-PEG. There were no gross anatomical or histopathological effects detected in non-reproductive organs. Uteri (luminal fluid imbibition) and ovaries (decreased folliculogenesis) were affected by treatment. Curcumin-PEG ip hastened the onset of puberty in immature female mice. Live births were reduced in mature females housed with males and treated iv with curcumin-PEG; mating (vaginal plugs) was not affected. Accessory gland weights, testicular testosterone concentrations, and spermatogenesis were diminished in mature male mice following iv curcumin-PEG. Estrogenic/antiandrogenic and pregnancy-disrupting effects of a water soluble/bioavailable curcumin were demonstrated.

MicroRNA-199a targets CD44 to suppress the tumorigenicity and multidrug resistance of ovarian cancer-initiating cells

In ovarian cancer, CD44(+) /CD117(+) stem cells, also known as cancer-initiating cells (CICs), are highly proliferative, have a low degree of differentiation, and are resistant to chemotherapeutics. Therefore, the CD44(+) /CD117(+) subpopulation is thought to be an important target for novel therapeutic strategies. In this study, we investigated the role of microRNA-199a (miR-199a) in ovarian cancer stem cells. Luciferase reporter gene assays confirmed that miR-199a targets CD44 via an miR-199a-binding site in the 3'-UTR. CD44(+) /CD117(+) ovarian CICs were enriched from human primary ovarian tumor tissues and confirmed by flow cytometric sorting. miR-199a was cloned and transfected into ovarian CICs. CD44 mRNA and protein expression was significantly decreased in miR-199a-transfected ovarian CICs as compared with miR-199a mutant-transfected and untransfected cells. Cell cycle analysis, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide proliferation assays, the colony formation assay and the transwell migration assay indicated that miR-199a significantly affected cell cycle regulation and suppressed the proliferation and invasive capacity of ovarian CICs in vitro. miR-199a significantly increased the chemosensitivity of ovarian CICs to cisplatin, pacitaxel, and adriamycin, and reduced mRNA expression of the multidrug resistance gene ABCG2 as compared with miR-199a mutant-transfected and untransfected cells. The expression of stemness markers was also significantly reduced in miR-199a-transfected CICs as compared with miR-199a mutant-transfected and untransfected ovarian cells. Furthermore, xenograft experiments confirmed that miR-199a suppressed the growth of xenograft tumors formed by ovarian CICs in vivo. Thus, expression of endogenous mature miR-199a may prevent tumorigenesis in human ovarian cancer by regulating expression of its target gene CD44.