Dasatinib (BMS-35482) has synergistic activity with paclitaxel and carboplatin in ovarian cancer cells

Purpose

To explore the activity of dasatinib alone and in combination with paclitaxel and carboplatin in ovarian cancer cells and to determine if dasatinib activity can be predicted based on evaluation of the SRC pathway.

Experimental design

Microarray analysis was performed for IGROV1, OVCAR3, A2780 and SKOV3 ovarian cancer cells and the status of the genomic SRC signature pathway was determined. Cells were treated with carboplatin, paclitaxel and dasatinib individually and in combination. Pre- and post-treatment phospho-SRC (pSRC) and SRC protein expression was determined. Dose-response curves were constructed, and drug interaction was assessed by the Combination Index (CI) method.

Results

SRC protein expression levels reflected the SRC pathway genomic signature in the cell lines with the lowest (SKOV3) and highest (IGROV1) pathway expression, but not in those with intermediate expression (OVCAR3, A2780). Dasatinib treatment caused loss of pSRC in all cell lines, with 50% growth inhibition for IGROV1 at 70 nM, OVCAR3 at 34 nM, A2780 at 4.1 μM and SKOV3 at 530 nM. Dasatinib combined with cytotoxics yielded a synergistic effect (CI = 0.46 to 0.79) in all cell lines except SKOV3.

Conclusion

Dasatinib in combination with standard chemotherapeutic agents appears to interact in a synergistic manner in some ovarian cancer cell lines. Further research is needed to evaluate tumor cell characteristics which predict response to dasatinib.     

Costunolide induces apoptosis in platinum-resistant human ovarian cancer cells by generating reactive oxygen species

Objective

The acquired resistance to platinum-based drugs has become an obstacle in the management of ovarian cancer. We investigated the apoptosis-inducing effect of costunolide, a natural sesquiterpene lactone, in platinum-resistant human ovarian cancer cells, along with the molecular mechanism of action.

Methods

Costunolide and cisplatin were examined in platinum-resistant human ovarian cancer cells. MTT assay for cell viability, PI staining for cell cycle profiling, and Annexin V assay for apoptosis analysis. ROS production and protein expression was assessed by H₂DCFDA staining and Western blotting, respectively. Combination effect was determined using the Combination Index (CI) method.

Results

It was found that costunolide is more potent than cisplatin in inhibiting cell growth in three platinum-resistant ovarian cancer cell lines (MPSC1^PT, A2780^PT, and SKOV3^PT). Costunolide induced apoptosis of platinum-resistant cells in a time- and dose-dependent manner and suppressed tumor growth in SKOV3^PT-bearing mouse model. In addition, costunolide triggered the activation of caspase-3, -8, and -9. Pretreatment with caspase inhibitors neutralized the pro-apoptotic activity of costunolide. We further demonstrated that costunolide induced a significant increase in intracellular reactive oxygen species (ROS). Additionally, the antioxidant N-acetyl-L-cysteine (NAC) significantly attenuated the costunolide-induced production of ROS, activation of caspases, down-regulation of Bcl-2, and apoptosis in platinum-resistant ovarian cancer cells. Moreover, costunolide synergized with cisplatin to induce cell death in platinum-resistant ovarian cancer cells.

Conclusions

Taken together, these data suggest that costunolide, alone or in combination with cisplatin, may be of therapeutic potential in platinum-resistant ovarian cancer.     

Brain metastases from epithelial ovarian carcinoma: evaluation of prognosis and managements - a Taiwanese Gynecologic Oncology Group (TGOG) study

Objective

To evaluate the characteristics and outcome of patients with brain metastases from epithelial ovarian carcinoma.

Methods

The clinical and pathologic characteristics, treatment and outcome of patients with brain metastases from epithelial ovarian carcinoma were analyzed from eight medical centers in Taiwan under the TGOG (Taiwanese Gynecologic Oncology Group).

Results

A total of 64 patients were recruited in this study. The incidence of brain metastases from epithelial ovarian carcinoma seemed to be increasing in recent years. The median survival from the diagnosis of brain metastases was 8 months (range: 0-72). Prior cancer relapse before the diagnosis of brain metastases, number of brain metastases and multimodal treatment were related to the duration of survival.

Conclusions

The prognosis for patients with brain metastases from epithelial ovarian carcinoma is generally poor. However, clinicians should keep alert to the neurological complaints of ovarian cancer patients and the patients might benefit from aggressive multimodal treatments.     

Glucose deprivation activates AMPK and induces cell death through modulation of Akt in ovarian cancer cells

Objectives

Upregulation of glycolysis has been demonstrated in multiple tumor types. Glucose deprivation results in diminished intracellular ATP; this is counteracted by AMPK activation during energy deficiency to restore ATP levels. We sought to determine whether glucose deprivation could induce cytotoxicity in ovarian cancer cells through activation of AMPK, and whether AMPK activators could mimic glucose deprivation induced cytotoxicity.

Methods

Sensitivity to 2DG induced cytotoxicity and glucose deprivation was determined in a panel of ovarian cancer cells. Cellular growth rate, rate of glucose uptake, and response to glucose deprivation were determined. Expression of Glut-1, HIF1-α, AMPK and Akt was determined by immunoblotting.

Results

Incubation of ovarian cancer cells with glucose-free media, 2-DG and AMPK activators resulted in cell death. The glycolytic phenotype of ovarian cancer cells was present in both normoxic and hypoxic conditions, and did not correlate with HIF1-α expression levels. Sensitivity to glucose deprivation was independent of growth rate, rate of glucose uptake, and appeared to be dependent upon constitutive activation of Akt. Glucose deprivation resulted in activation of AMPK and inhibition of Akt phosphorylation. Treatment with AMPK activators resulted in AMPK activation, Akt inhibition, and induced cell death in ovarian cancer cells.

Conclusions

Ovarian cancer cells are glycolytic as compared to normal, untransformed cells, and are sensitive to glucose deprivation. Because ovarian cancer cells are dependent upon glucose for growth and survival, treatment with AMPK activators that mimic glucose deprivation may result in broad clinical benefits to ovarian cancer patients.     

Green tea for ovarian cancer prevention and treatment: a systematic review of the in vitro, in vivo and epidemiological studies

Objective

This systematic review was conducted to examine the effects of green tea or green tea components on the prevention and progression of epithelial ovarian cancer.

Methods

Using Medline, EMBASE and SciVerse (last researched: July 2011), we retrieved 22 articles including 5 epidemiological studies.

Results

In epithelial ovarian cancer cell lines, green tea and green tea components have been shown to downregulate the expression of proteins involved in inflammation, cell signalization, cell motility and angiogenesis. Green tea and green tea components would induce apoptosis and could potentiate the effects of cisplatin, a chemotherapeutic agent. In human observational studies, significant associations between green tea intake and both decreased ovarian cancer occurrence and better prognosis were reported.

Conclusions

Available literature suggests potential molecular targets for green tea in ovarian cancer treatment and also provides data supporting the clinical evaluation of the role of green tea or green tea components in ovarian cancer prevention and treatment.     

Novel nanotechnology approaches to diagnosis and therapy of ovarian cancer

Objective

Ovarian carcinoma is the leading cause of death from gynecologic malignancies, which is a direct outcome of missing its diagnosis at an early stage. Approximately 75% of ovarian cancer patients are initially diagnosed with disseminated intra-abdominal disease (stages III-IV) when ~ 30% of patients have a 5-year survival rate. In addition to the challenge of early detection of ovarian cancer, its therapy presents several challenges including the route of therapy, resistance to therapy with recurrence of cancer, and specific targeting of ovarian cancer to reduce cytotoxic side effects.

Methods

We reviewed recent literature employing nanotechnology approaches to diagnosis and therapy of ovarian cancer.

Results

Recent innovations in nanotechnology with applications in cancer diagnostics and therapy help circumvent many pre-existing problems with conventional chemotherapy and present new ways of diagnosis and therapy.

Conclusions

Nanotechnology has promising potential in enhancing early detection of ovarian cancer and treatment of recurrent disease.     

Elafin selectively regulates the sensitivity of ovarian cancer cells to genotoxic drug-induced apoptosis

Objective

Elafin has been reported to be abundantly expressed in human epithelial ovarian carcinoma (EOC), however, its functions are poorly understood. Here, we evaluated the role of elafin in modulating the sensitivity of human EOC cells to chemotherapeutic drugs.

Methods

Elafin expression was determined by ELISA in 9 established human EOC cell lines. A lentivirus encoding elafin-specific shRNA was used to down-regulate elafin expression in OVCAR3 and OV433 cells, and a plasmid encoding elafin was used to ectopically express elafin in elafin-negative SKOV3 cells. Sensitivity to cisplatin and other genotoxic agents and to paclitaxel, an inhibitor of microtubule depolymerization, was examined in OVCAR3, OV433 and SKOV3 sublines. Cell viability was determined by the MTT assay, apoptosis by annexin V/7-AAD staining and caspase activation by fluorimetric assay.

Results

Knockdown of the elafin gene decreases cisplatin IC50 by at least 2-folds in OVCAR3 and OVCAR433 cells (p < 0.01) but does not affect paclitaxel IC50. The sensitivity to other genotoxic agents such as carboplatin, cyclophosphamide and 5-fluorouracil was also increased by silencing the expression of elafin. Apoptosis and caspase-3 activation were significantly augmented in cisplatin-treated OVCAR3 cells with silenced elafin. Overexpression of elafin in SKOV3 cells made them more resistant to cisplatin and decreased cisplatin-induced apoptosis and caspase activation (p < 0.01).

Conclusions

Expression of elafin decreases the sensitivity of human EOC cells to several genotoxic agents, which may have an important implication in predicting the response of patients with EOC to chemotherapy in the clinic.     

Correlation of macroscopic and microscopic pathology in risk reducing salpingo-oophorectomy: implications for intraoperative specimen evaluation

Objective

A minority of risk-reducing salpingo-oophorectomy (RRSO) specimens from BRCA mutation carriers will contain clinically occult carcinoma that is detectable only using a specialized pathologic evaluation protocol. Although intraoperative detection of cancer may alter immediate surgical management, technical complications impairing pathologic diagnosis may result if fresh tissue dissection and frozen sections are performed on unselected RRSO specimens. We hypothesize that macroscopic specimen findings may predict which RRSO specimens contain cancer and therefore may guide selection of specimens for intraoperative pathologic evaluation. The aim of this study was to correlate the macroscopic and microscopic pathologic findings in RRSO.

Methods

RRSO specimens from 134 women with a BRCA mutation were retrospectively classified by their grossly visible findings (cysts and/or nodules versus grossly unremarkable). Correlation of the gross findings with the microscopic finding of occult tubal and/or ovarian carcinoma was performed by re-examination of all pathology slides.

Results

While 46% of RRSO had visible ovarian cysts and 34% had visible tubal/paratubal cysts, no cyst contained cancer on microscopic examination. Carcinoma was detected in 2/22 (9%) visible ovarian nodules and in 2/8 (25%) visible tubal nodules. Conversely, among all 11 RRSO specimens containing cancer, 7 (64%) had no corresponding visible abnormality.

Conclusion

Frozen section evaluation of a solid nodule may be valuable in patients consented for immediate surgical staging. Otherwise it is best to avoid intraoperative dissection or frozen section of RRSO that are macroscopically normal or contain only cysts; such specimens should remain undissected for immediate formalin-fixation as the first step of the specialized pathology evaluation protocol.     

A novel genome-based approach correlates TMPRSS3 overexpression in ovarian cancer with DNA hypomethylation

Objective

In an attempt to analyze more profoundly aberrant DNA hypomethylation in epithelial ovarian cancer (EOC), we applied a novel genome-based approach which includes expression profiling following pharmacologic stimulation of DNA methylation with the methyl donor S-adenosyl-l-methionine (SAM).

Methods

Four different EOC cell lines (OVCAR3, SKOV3, TOV21 and TOV112) were treated with SAM, and gene expression profiling was performed in SAM-treated and control EOC cells. Genes, downregulated upon SAM treatment were considered as potentially hypomethylated in EOC. DNA hypomethylation was independently validated in ovarian tumor and control tissues by bisulfite sequencing PCR (BSP).

Results

Among the genes identified, one of particular interest was the type II serine protease TMPRSS3 gene variants A and D (TMPRSS3-A/D), previously recognized as overexpressed in EOC and representing potential EOC therapeutic targets. Consecutive BSP analysis demonstrated that the common putative promoter region of the TMPRSS3-A/D gene variants was significantly hypomethylated in high-grade serous EOC tumors, compared to low-malignant potential ovarian tumors and normal ovarian tissue.

Conclusions

Our data imply that TMPRSS3-A/D overexpression in EOC is probably due to hypomethylation of their control region thus indicating that TMPRSS3-A/D variants could also represent novel molecular targets for epigenetic therapy of late stages of the disease. Our results also suggest that the frequently observed upregulation of different members of the type II serine proteases gene family in advanced cancer could be due to aberrant DNA hypomethylation. Furthermore, our study introduces a promising discovery approach that could be used for the identification of hypomethylated genes in different experimental cell models.     

Clear cell carcinoma of the ovary: a review of the literature

Objective

Different histologic types of epithelial ovarian cancer may represent different diseases with unique clinical and molecular characteristics. Clear cell carcinoma (CCC) of the ovary has been reported as having a worse prognosis than high grade serous epithelial ovarian cancer (EOC). This article critically reviews the literature pertinent to the pathology, pathogenesis, diagnosis, management, and outcome of patients with ovarian CCC.

Methods

MEDLINE was searched for all research articles published in English between January 01, 1977 and January 30, 2012 which reported on patients diagnosed with ovarian CCC. Given the rarity of this tumor, studies were not limited by design or number of reported patients.

Results

Ovarian CCC tumors represent 5-25% of ovarian cancers. Its histologic diagnosis can be challenging, resulting often times in misclassification of these tumors. Ovarian CCC tends to present at earlier stages and has been associated with endometriosis, ARID1A and PIK3CA mutations. When compared to stage-matched controls, patients with early-stage ovarian CCCs may have a better prognosis than patients with high-grade serous tumors. For those with advanced stage disease, high-grade serous histology confers a better prognosis than ovarian CCC. Patients with Stage IC-IV have a relatively poor prognosis and efforts should center in discovery of more effective treatment strategies.

Conclusions

Ovarian CCC is a biologically distinct entity, different from high-grade serous EOC. Future studies should explore the role of targeted therapies in the management of ovarian CCC.     

High-mobility group protein B1 (HMGB1) is a novel biomarker for human ovarian cancer

Background

High mobility group box l (HMGB1), a nuclear and extracellular protein, is implicated in some physiologic and pathologic conditions. In this study, we investigated the expression and function of HMGB1 in ovarian cancer.

Methods

cDNA microarray analysis was performed to compare gene expression profiles of the highly invasive and the low invasive subclones derived from the SKOV3 human ovarian cancer cell line. Immunohistochemistry (IHC) staining was performed to investigate HMGB1 expression in a total of 100 ovarian tissue specimens. In functional assays, effects of HMGB1 knockdown on the biological behavior of ovarian cancer cells were investigated.

Results

HMGB1 was overexpressed in the highly invasive subclone compared with the low invasive subclone. High HMGB1 expression was associated with poor clinicopathologic features. Knockdown of HMGB1 expression significantly suppressed ovarian cancer cell proliferation accompanied by decreased cyclin D1 and PCNA expression, and inhibited cell migration and invasion accompanied by decreased MMP2 and MMP9 activities.

Conclusion

HMGB1 is a newly identified gene overexpressed in ovarian cancer and associated with poor clinicopathologic features. HMGB1 may serve as a new biomarker and a therapeutic target for ovarian cancer in the future.     

Multidisciplinary management of malignant ovarian germ cell tumours

Objectives

Malignant ovarian germ cell tumours (MOGCT) are rare cancers of young women. Limited prospective trials exist from which evidence-based management can be developed. This review summarizes the available literature concerning MOGT in order to provide the clinician with information relevant to their multidisciplinary management.

Methods

MEDLINE was searched between 1966 and 2010 for all publications in English where the studied population included women diagnosed with malignant ovarian germ cell tumours.

Results

The majority of patients can be cured with fertility-preserving surgery with or without combination chemotherapy. Long term survival approaches 100% in early stage disease and is approximately 75% in advanced stage disease. Most studies suggest that the treatment has little, if any, effect on future fertility and limited data suggest that there is no adverse effect on the future quality of life.

Conclusion

MOGCTs are rare tumours of young women the majority of which can be successfully treated with fertility-preserving surgery with or without chemotherapy with preservation of reproductive function. Minimisation of chemotherapy in good prognostic groups and improved treatment in resistant and relapsed MOGCT are important goals for the future. Further studies are needed to quantify the late adverse effects of treatment in long term survivors.     

MUC16 (CA125) regulates epithelial ovarian cancer cell growth, tumorigenesis and metastasis

Objectives

MUC16 (CA125) protein is a high molecular weight mucin overexpressed in the majority of epithelial ovarian cancers (EOC) but not in the epithelium of normal ovaries suggesting that it might play a role in EOC pathogenesis. Here, we explored the phenotypic consequences of MUC16 knockdown and expression of its C-terminal domain with the aim of establishing a role for MUC16 in tumorigenesis.

Methods

MUC16 was down-regulated by stably expressing an anti-MUC16 endoplasmic reticulum-targeted single-chain antibody which prevented MUC16 cell surface localization in NIH:OVCAR3 cells. In addition, we generated epitope tagged, N-terminal region-deleted MUC16 constructs with (MUC16TMU) and without (MUC16CTD) cytoplasmic tail deletions and stably expressed them in SKOV3 cells.

Results

Although MUC16 knockdown did not affect the cell growth rate, knockdown cells reached a stationary growth phase after 4 days whereas control cells continued to grow for up to 7 days. Colony formation assays in soft agar demonstrated that MUC16 knockdown cells had > 8-fold reduction in their ability to form colonies. Importantly, MUC16 knockdown completely prevents the formation of subcutaneous tumors in nude mice. Conversely, we show that ectopic expression of the MUC16CTD enhances SKOV3 tumor cell growth, colony formation in soft agar and enhances tumor growth and metastases in SCID mice. In addition, MUC16CTD expression increases cell motility, invasiveness, and metastatic property. Deletion of the cytoplasmic tail from the MUC16CTD completely abolished its ability to enhance tumor cell growth, cell motility and invasiveness. Furthermore, the increased invasive properties of MUC16CTD-expressing cells correlated with decreased expression of E-cadherin and increased expression of N-cadherin and vimentin.

Conclusion

These findings provide the first evidence for a critical role of MUC16 in tumor cell growth, tumorigenesis and metastases.     

Prognosis of ovarian clear cell carcinoma compared to other histological subtypes: a meta-analysis

Objective

To compare the survival outcome between clear cell carcinoma (CCC) and other histological subtypes in epithelial ovarian carcinoma (EOC).

Methods

From January 1974 to February 2011, we identified a total of 31,800 (CCC; 2152, non-CCC; 29648) patients from 12 studies meeting the inclusion criteria.

Results

Heterogeneity tests demonstrated significant between-study variation (I² = 92.1%) with no significant difference in hazard ratio (HR) for death between CCC and non-CCC (HR; 1.16, 95% CI; 0.85-1.57, random-effects model). Comparing the HR based on stage I + II, and stage III + IV, between CCC and non-CCC, showed that CCC patients had a higher hazard rate for death than those with non-CCC of the ovary (stage I + II; HR; 1.17, 95% CI; 1.01-1.36, stage III + IV; HR; 1.65, 95% CI; 1.52-1.79). In a comparison of CCC and serous EOC, advanced stage (III and IV) CCC only showed a poorer hazard rate for death than serous EOC (HR; 1.71, 95% CI; 1.57-1.86).

Conclusion

This analysis suggests that ovarian CCC patients had poorer prognosis than those with other histological subtypes of EOC, especially in advanced EOC stages. Different treatment strategies may be needed for patients with ovarian CCC.     

Expression of indoleamine 2,3-dioxygenase predicts shorter survival in patients with vulvar squamous cell carcinoma (vSCC) not influencing on the recruitment of FOXP3-expressing regulatory T cells in cancer nests

Objective

Regulatory T cells (Tregs), and the enzyme indoleamine 2,3-dioxygenase (IDO), have potential regulatory properties for immune escape in cancer. Inhibitors of IDO are available and could potentially be used in vulvar cancer if IDO was proved to drive progression of the disease. The aim of this study was to evaluate the expression of factor forkhead boxP3 (FOXP3), a marker of Tregs, and IDO in vulvar squamous cell carcinoma (vSCC), and to verify their prognostic significance.

Methods

76 primary tumors and 35 lymph node metastases derived from 76 patients with full clinical history were analyzed. The intratumoral infiltration of Tregs and IDO expression within cancer were evaluated by immunohistochemistry.

Results

The number of Tregs in primary tumor and in corresponding lymph node metastasis was significantly correlated. Intensity of Treg infiltrates in the primary and metastatic sites was not correlated to IDO expression and had no influence on the overall patient survival. High IDO expression was associated with significantly worse overall survival among vSCC patients and was found to be an independent prognostic factor similarly to the tumor grade and patient's age.

Conclusions

The degree of intratumoral Treg infiltrates is an individual feature and remains stable throughout the course of the disease without impact on the patient's survival. IDO expression predicts shorter survival of vSCC patients. If immunologic tolerance of the tumor is promoted by the overexpression of IDO it will not influence the number of intratumoral Tregs. IDO expression seems to be an independent prognostic factor in patients with vSCC.     

Synchronous early-stage endometrial and ovarian cancer

Objective

To explore the clinicopathologic findings and oncological outcome of early-stage synchronous endometrial and ovarian malignancies.

Methods

A retrospective study of 93 women with synchronous stage I ovarian and stage I-II endometrial cancer treated between December 1981 and August 2005 in the gynecologic oncology department of San Gerardo Hospital, Italy.

Results

Fifty-one percent of the ovarian tumors were stage Ia and 71% of the endometrial cancers had minimal myometrial invasion. Endometrioid histology and grade 2 disease were prevalent in both sites. Hyperplasia and endometriosis coexisted in 71% and 22% of endometrial and ovarian cancers, respectively. The actuarial 5-year disease-free and overall survival rates were 83% and 96%, respectively.

Conclusion

The incidence of synchronous endometrial and ovarian cancer is not negligible, especially among young women. Synchronous cancers show very favorable pathologic features and have an excellent oncologic outcome. Adjuvant therapy should be tailored according to surgical staging and histology.     

Phase II trial of lapatinib and topotecan (LapTop) in patients with platinum-refractory/resistant ovarian and primary peritoneal carcinoma

Objective

Resistance to chemotherapy is a major challenge in the treatment of ovarian/peritoneal cancer. One purported mechanism of topotecan resistance is the breast cancer resistance protein (BCRP) and P-glycoprotein (Pgp). We designed a phase II clinical trial evaluating the efficacy and adverse event profile of concomitant topotecan and lapatinib, a small molecule pan-erbB inhibitor that can block BCRP/Pgp efflux of topotecan.

Methods

Patients with platinum-refractory or resistant epithelial ovarian/peritoneal cancer were treated with topotecan 3.2 mg/m2 IV on Day 1, 8 and 15 and lapatinib 1250 mg PO daily, continuously in 28 day cycles. The primary endpoint was response rate. For correlative studies, archived tissue was assessed for expression of EGFR, HER2, HIF-1α, CD31, and BCRP.

Results

Eighteen patients were enrolled and treated. Four experienced evidence of clinical benefit: one partial response and three with stable disease. Using a two-stage Simon design, the trial was stopped after the first stage due to insufficient activity. Grades 3+ and 4+ adverse events (AE) were experienced in 14 and 4 patients, respectively. The most common grade 3/4 AE were neutropenia (56%), thrombocytopenia (28%), and diarrhea (22%).

Conclusions

The combination of lapatinib plus topotecan for the treatment of platinum refractory/resistant epithelial ovarian cancer lacks sufficient activity to warrant further investigation. In particular, hematologic adverse events were substantial. Expression of correlative study markers did not reveal patterns of predicted benefit or toxicity. Disruption of erbB signaling and BCRP/Pgp efflux with lapatinib was insufficient for overcoming topotecan resistance, suggesting alternative mechanisms of resistance are involved.