Overcoming platinum resistance in ovarian carcinoma

Overexpression of CHI3L1 is associated with chemoresistance and poor outcome of epithelial ovarian carcinoma

We propose CHI3L1 as a prognostic biomarker for patients with epithelial ovarian carcinoma (EOC) and also suggest possible biological functions of CHI3L1. We measured CHI3L1 expression with quantitative real time-polymerase chain reaction (qRT-PCR) in 180 women with EOC and evaluated correlations between CHI3L1 expression, clinicopathological characteristics, and the outcomes of the patients. The expression of CHI3L1 was higher in cancerous tissues than in normal tissues. The expression of CHI3L1 was also higher in patients with a serous histological type, advanced stage, and chemoresistance. Patients with high CHI3L1 expression had a shorter progression-free survival (p < 0.001)and overall survival (p < 0.001). Patients with high CHI3L1 expression also had a high risk of recurrence (p < 0.001)and death (p < 0.001). In vitro studies showed that CHI3L1 up-regulated the expression of anti-apoptotic Mcl-1 protein and hampered paclitaxel-induced apoptosis of ovarian cancer cells. These results suggest that CHI3L1 shows potential as a prognostic biomarker for EOC. CHI3L1 may promote chemoresistance via inhibition of drug-induced apoptosis by up-regulating Mcl-1.

Proton pump inhibitors enhance the effects of cytotoxic agents in chemoresistant epithelial ovarian carcinoma

This study was designed to investigate whether proton pump inhibitors (PPI, V-ATPase blocker) could increase the effect of cytotoxic agents in chemoresistant epithelial ovarian cancer (EOC). Expression of V-ATPase protein was evaluated in patients with EOC using immunohistochemistry, and patient survival was compared based on expression of V-ATPase mRNA from a TCGA data set. In vitro, EOC cell lines were treated with chemotherapeutic agents with or without V-ATPase siRNA or PPI (omeprazole) pretreatment. Cell survival and apoptosis was assessed using MTT assay and ELISA, respectively. In vivo experiments were performed to confirm the synergistic effect with omeprazole and paclitaxel on tumor growth in orthotopic and patient-derived xenograft (PDX) mouse models. Expression of V-ATPase protein in ovarian cancer tissues was observed in 44 patients (44/59, 74.6%). Higher expression of V-ATPase mRNA was associated with poorer overall survival in TCGA data. Inhibition of V-ATPase by siRNA or omeprazole significantly increased cytotoxicity or apoptosis to paclitaxel in chemoresistant (HeyA8-MDR, SKOV3-TR) and clear cell carcinoma cells (ES-2, RMG-1), but not in chemosensitive cells (HeyA8, SKOV3ip1). Moreover, the combination of omeprazole and paclitaxel significantly decreased the total tumor weight compared with paclitaxel alone in a chemoresistant EOC animal model and a PDX model of clear cell carcinoma. However, this finding was not observed in chemosensitive EOC animal models. These results show that omeprazole pretreatment can increase the effect of chemotherapeutic agents in chemoresistant EOC and clear cell carcinoma via reduction of the acidic tumor microenvironment.

Gemcitabine-oxaliplatin (GEMOX) for epithelial ovarian cancer patients resistant to platinum-based chemotherapy

BACKGROUND

Patients with platinum-resistant epithelial ovarian cancer (EOC) experience poor outcome. Currently, no clearly superior management strategy exists for platinum-resistant EOC patients.

PURPOSE

Analyze the efficacy and safety of gemcitabine-oxaliplatin (GEMOX) in platinum resistant EOC patients.

PATIENTS AND METHODS

Thirty-two patients with platinum-based resistant EOC were included. Studied patients had received GEM at the dose of 1000mg/m(2) on days 1 and 8 and OX 100mg/m(2) on day 1, administered over 2h 30min after GEM infusion of 3week treatment cycle.

RESULTS

In the evaluation of tumor response, none of patients had achieved CR while PR, SD, were observed in 7 (21.9%), 9 (28.1%) respectively, clinical benefit (CR+PR+SD) was recorded in 50% of patients while PD was observed in 16 (50%) patients. In regard to survival, the median value of OS was 10.5months (range, 2.2-17.5months). The median value of PFS was 6.37months (range, 1-17.5months). The one-year OS rate was 34.4% and the one-year PFS rate was 12.5%. Concerning hematological toxicity grade 3 neutropenia was recorded in 4 (12.5%) patients while grade 4 febrile neutropenia was recorded in 2 (6.3%) patients and grade 4 anemia was represented by 3.1%. Grade 1-2 fatigue was the most common non-hematological toxicity and represented by 65.6% of patients. Grade 3 non hematological toxicity was recorded with nausea/vomiting and hepatic toxicity represented by 3.1% for both.

CONCLUSION

The GEMOX combination is a regimen with a moderate therapeutic efficacy and tolerable toxic side effects in patients with platinum-resistant EOC.

Clinical outcome of treatment with serine-threonine kinase inhibitors in recurrent epithelial ovarian cancer: a systematic review of literature

INTRODUCTION

While serine-threonine kinases (STK) are attractive therapeutic targets in epithelial ovarian cancer, clinical outcomes of STK inhibitors in the management of recurrent disease have not been completely described.

AREAS COVERED

A systematic literature review of published clinical studies on STK inhibitors targeting mTOR, MAPK, and aurora kinase pathways in recurrent epithelial ovarian cancer was conducted, revealing 18 clinical trials (497 patients). Pooled analyses were performed to assess treatment response, survival time, and adverse events. Median progression-free survival was 3.4 months in STK inhibitor-based therapy, and the average response rate and clinical benefit rate were 13% and 67%, respectively. Among regimens comprised of only STK inhibitors (11 trials, 299 patients), median progression-free time was 2.7 months, response rate was 10%, and clinical benefit rate was 64%. Compared to single STK inhibitor monotherapy (52.5%), clinical benefit rates significantly improved when STK inhibitors were combined with a cytotoxic agent (71.4%), other class biological agent (74.2%), or an additional STK inhibitor (95.0%) (all, P ≤ 0.002).

EXPERT OPINION

STK inhibitor-based therapy showed modest activity for recurrent epithelial ovarian cancer with reasonable clinical benefit rates, suggesting its potential utility for maintaining disease stability if supported by future studies. Efficacy appears greatly improved in appropriately selected patient populations, especially those with low-grade serous ovarian carcinoma, platinum-sensitive disease, cancers with somatic RAS or BRAF mutations, and when used in a combination regimen with a cytotoxic or biological agent.

DOXIL when combined with Withaferin A (WFA) targets ALDH1 positive cancer stem cells in ovarian cancer

Ovarian cancer is a highly aggressive and deadly disease. Currently, the treatment for ovarian cancer entails cytoreductive surgery followed by chemotherapy, mainly cisplatin or carboplatin combined with paclitaxel. Although this regimen is initially effective in a high percentage of cases, unfortunately, after few months of initial treatment, tumor relapse occurs due to platinum-resistance. DOXIL (liposomal preparation of doxorubicin) is a choice of drug for recurrent ovarian cancer. However, its response rate is very low and is accompanied by myocardial toxicity. Resistance to chemotherapy and recurrence of cancer is primarily attributed to the presence of cancer stem cells (CSCs), a small population of cells present in cancer. Effect of DOXIL and withaferin A (WFA), both alone and in combination, was investigated on cell proliferation of ovarian cancer cell line A2780 and tumor growth in SCID mice bearing i.p. ovarian tumors. ALDH1 cells were isolated from A2780 using cell sorter, and effect of DOXIL and WFA both alone and in combination on tumorigenic function of ALDH1 was studied using spheroids formation assays in vitro. Western blots were performed to examine the expression of ALDH1 and Notch 1 genes. In our studies, we showed, for the first time, that DOXIL when combined with withaferin A (WFA) elicits synergistic effect on inhibition of cell proliferation of ovarian cancer cells and inhibits the expression of ALDH1 protein, a marker for ALDH1 positive cancer stem cells (CSCs), and Notch1, a signaling pathway gene required for self-renewal of CSCs. Inhibition of expression of both ALDH1 and Notch1 genes by WFA was found to be dose dependent, whereas DOXIL (200 nM) was found to be ineffective. SCID mice, bearing i.p. ovarian tumors, were treated with a small dose of DOXIL (2 mg/kg) in combination with a sub-optimal dose of WFA (2 mg/kg) which resulted in a highly significant (60% to 70%) reduction in tumor growth, and complete inhibition of metastasis compared to control. In contrast, WFA treatment showed a significant reduction in tumor growth but no change in metastasis compared to control. DOXIL showed non-significant reduction in tumor growth and no change in metastasis compared to control. Isolated ALDH1 positive CSCs treated with the combination of DOXIL and WFA resulted in a significant reduction in spheroids formation (tumorigenic function of CSCs) and expression of ALDH1 protein. WFA when used alone at a concentration of 1.5 μM was found to be highly effective in suppression of ALDH1 expression, whereas DOXIL at a concentration of 200 nM was found to be ineffective. DOXIL in combination with WFA elicits synergistic effects, targets cancer stem cells, and has potential to minimize induction of drug resistance and reoccurrence of cancer. Based on our studies, we conclude that the combination of DOXIL with WFA has the potential to be an effective therapy for ovarian cancer and may ameliorate DOXIL related side effects as well as recurrence of ovarian cancer leading to increase in patients' survival rate.

Therapeutic evaluation of microRNA-15a and microRNA-16 in ovarian cancer

Treatment of chemo-resistant ovarian cancer (OvCa) remains clinically challenging and there is a pressing need to identify novel therapeutic strategies. Here we report that multiple mechanisms that promote OvCa progression and chemo-resistance could be inhibited by ectopic expression of miR-15a and miR-16. Significant correlations between low expression of miR-16, high expression of BMI1 and shortened overall survival (OS) were noted in high grade serous (HGS) OvCa patients upon analysis of The Cancer Genome Atlas (TCGA). Targeting BMI1, in vitro with either microRNA reduced clonal growth of OvCa cells. Additionally, epithelial to mesenchymal transition (EMT) as well as expression of the cisplatin transporter ATP7B were inhibited by miR-15a and miR-16 resulting in decreased degradation of the extra-cellular matrix and enhanced sensitization of OvCa cells to cisplatin. Nanoliposomal delivery of the miR-15a and miR-16 combination, in a pre-clinical chemo-resistant orthotopic mouse model of OvCa, demonstrated striking reduction in tumor burden compared to cisplatin alone. Thus, with the advent of miR replacement therapy some of which are in Phase 2 clinical trials, miR-15a and miR-16 represent novel ammunition in the anti-OvCa arsenal.

2-Deoxy-d-Glucose Sensitizes Human Ovarian Cancer Cells to Cisplatin by Increasing ER Stress and Decreasing ATP Stores in Acidic Vesicles

Cisplatin is a commonly used chemotherapeutic agent; however, the development of acquired resistance limits its application. Here, we demonstrate that 2-deoxy-d-glucose (2-DG) enhanced the antitumor effects of cisplatin in SKOV3 cells, which include inhibition of proliferation and promotion of apoptosis. Additionally, either cisplatin or 2-DG alone could upregulate the endoplasmic reticulum (ER) stress-associated protein glucose-regulated protein-78 (GRP78). Moreover, exposure to 2-DG increased the expression of GRP78 induced by cisplatin. Cisplatin also upregulated ER stress-associated apoptotic protein 153/C/EBP homology protein (CHOP) in SKOV3 cells. While treatment with 2-DG alone could not upregulate the CHOP expression, a combination of both 2-DG and cisplatin increased the protein levels of CHOP above those induced by Cisplatin alone. Finally, cisplatin mediated an increase in ATP stores within acidic vesicles, whereas 2-DG decreased this effect. These data demonstrate that 2-DG sensitizes SKOV3 cells to cisplatin by increasing ER stress and decreasing ATP stores in acidic vesicles.

TOP2A gene copy gain predicts response of epithelial ovarian cancers to pegylated liposomal doxorubicin: TOP2A as marker of response to PLD in ovarian cancer

OBJECTIVE

The treatment of platinum resistant/refractory epithelial ovarian cancer (EOC) is a challenge for oncologists. One of the most utilized drugs in these patients is pegylated liposomal doxorubicin (PLD). As PLD is active only in a small subset of patients and causes side effects, selection of responsive patients is an unmet need and might be guided by the status of the DNA topoisomerase II alpha (TOP2A) that is poisoned by the drug.

METHODS

From 176 ovarian cancers treated in three institutions, we selected 38 patients treated with PLD monotherapy as second/third line of treatment. TOP2A gene copies were measured using Fluorescent In Situ Hybridization (FISH) and expression evaluated using immunohistochemistry. Patients' derived xenografts (PDXs) of ovarian cancers were used to assess the correlation between TOP2A protein expression and response to PLD.

RESULTS

Clinical data showed that TOP2A gene gain that is paralleled by increased expression of the protein, was associated with a higher probability of clinical benefit from PLD. Treatment of PDXs demonstrated that only xenografts showing a high percentage of TOP2A expressing cells underwent tumor shrinkage when treated with PLD.

CONCLUSIONS

These data show that TOP2A gene gain and protein over-expression might predict activity of PLD in platinum resistant/refractory EOC.

Effect of lymphovascular space invasion on survival of stage I epithelial ovarian cancer

OBJECTIVE

To evaluate the effect of lymphovascular space invasion on survival of patients with early-stage epithelial ovarian cancer.

METHODS

A multicenter retrospective study was conducted for patients with stage IA-C epithelial ovarian cancer who underwent primary comprehensive surgery including lymphadenectomy. Histopathology slides for ovarian tumors were examined by gynecologic pathologists for the presence or absence of lymphovascular space invasion. Survival analysis was performed examining tumoral factors.

RESULTS

A total of 434 patients were included in the analysis. Lymphovascular space invasion was detected in 76 (17.5%) patients associated with histology (P=.042) and stage (P=.044). Lymphovascular space invasion was significantly associated with decreased survival outcomes (disease-free survival, 5-year rate 78.4% compared with 90.7%, P=.024 and overall survival, 84.9% compared with 93.2%, P=.031) in univariate analysis. In multivariate analysis, lymphovascular space invasion did not remain a significant variable for disease-free survival (hazard ratio [HR] 1.98, 95% confidence interval [CI] 0.97-3.97, P=.059) or overall survival (HR 2.41, 95% CI 0.99-5.85, P=.052). Lymphovascular space invasion was associated with increased risk of hematogenous and lymphatic metastasis (HR 4.79, 95% CI 1.75-13.2, P=.002) but not peritoneal metastasis (P=.33) in multivariate analysis. Among lymphovascular space invasion-expressing tumors, patients who received fewer than six cycles of postoperative chemotherapy had significantly poorer disease-free survival than those who received six or more cycles (HR 4.59, 95% CI 1.20-17.5, P=.015).

CONCLUSION

Lymphovascular space invasion is an important histologic feature to identify a subgroup of patients with increased risk of recurrence in stage I epithelial ovarian cancer.

LEVEL OF EVIDENCE

III.

Withaferin a alone and in combination with cisplatin suppresses growth and metastasis of ovarian cancer by targeting putative cancer stem cells

Currently, the treatment for ovarian cancer entails cytoreductive surgery followed by chemotherapy, mainly, carboplatin combined with paclitaxel. Although this regimen is initially effective in a high percentage of cases, unfortunately within few months of initial treatment, tumor relapse occurs because of platinum-resistance. This is attributed to chemo-resistance of cancer stem cells (CSCs). Herein we show for the first time that withaferin A (WFA), a bioactive compound isolated from the plant Withania somnifera, when used alone or in combination with cisplatin (CIS) targets putative CSCs. Treatment of nude mice bearing orthotopic ovarian tumors generated by injecting human ovarian epithelial cancer cell line (A2780) with WFA and cisplatin (WFA) alone or in combination resulted in a 70 to 80% reduction in tumor growth and complete inhibition of metastasis to other organs compared to untreated controls. Histochemical and Western blot analysis of the tumors revealed that inclusion of WFA (2 mg/kg) resulted in a highly significant elimination of cells expressing CSC markers - CD44, CD24, CD34, CD117 and Oct4 and downregulation of Notch1, Hes1 and Hey1 genes. In contrast treatment of mice with CIS alone (6 mg/kg) had opposite effect on those cells. Increase in cells expressing CSC markers and Notch1 signaling pathway in tumors exposed to CIS may explain recurrence of cancer in patients treated with carboplatin and paclitaxel. Since, WFA alone or in combination with CIS eliminates putative CSCs, we conclude that WFA in combination with CIS may present more efficacious therapy for ovarian cancer.

BRCA1-IRIS inactivation sensitizes ovarian tumors to cisplatin

Ovarian cancer is the first in mortalities among gynecologic cancers in the United States, often due to late diagnosis and/or acquired platinum-resistant recurrences. This study investigates whether BRCA1-IRIS is a novel treatment target for ovarian cancers and in platinum-resistant recurrences. Here we show that more than half of the ovarian cancer samples analyzed showed BRCA1-IRIS and survivin overexpression and lacked nuclear FOXO3a expression. Normal ovarian epithelial cells overexpressing BRCA1-IRIS formed metastasis in mice when injected in the peritoneal cavity, whereas aggressive ovarian cancer cell lines failed to form tumors or metastases in mice when BRCA1-IRIS was silenced in them. We show that BRCA1-IRIS activates two autocrine signaling loops, brain-derived neurotrophic factor/tyrosine kinase B receptor (BDNF/TrkB) and neuregulin 1 (NRG1)/ErbB2. These loops are involved in anoikis resistance and metastasis promotion. These loops operate in several ovarian cancer cell lines, and BRCA1-IRIS silencing or inactivation using a novel inhibitory peptide renders both non-functional and promoted cell death. In a mouse xenograft model, BRCA1-IRIS inactivation using this novel inhibitory peptide resulted in significant reduction in ovarian tumor growth. More importantly, this treatment sensitized ovarian tumors to low cisplatin concentrations. Taken together, these data strongly suggest that BRCA1-IRIS and/or BDNF/TrkB and NRG1/ErbB2 could serve as rational therapeutic targets for advanced ovarian cancers.

Anti-tumour activity of phosphoinositide-3-kinase antagonist AEZS-126 in models of ovarian cancer

PURPOSE

Platinum resistance is the most crucial problem for treatment of ovarian cancer. There is a clinical need for new treatment strategies which overcome platinum resistance. Recently high level of AKT was shown to be involved in platinum resistance and furthermore in resistance against Natural-killer (NK)-cell mediated killing in ovarian cancer.

METHODS

Here, we investigate the ability of the PI3K/AKT inhibitor AEZS-126 alone and in combination with rapamycin to selectively target ovarian cancer cell proliferation and survival in vitro by MTT-assays and FACS based analysis. Furthermore the mechanism of cytotoxicity is analysed by FACS based assays. The NK-killing efficiency of ovarian cancer cells with and without pre-treatment with AEZS-126 was analysed.

RESULTS

AEZS-126 showed good anti-tumour activity in in vitro models of ovarian cancer. Main mechanism of cytotoxicity seems to be necroptosis which could be abrogated by co-incubation with necrostatin-1. Furthermore pre-treatment of platinum resistant cells with AEZS-126 resulted in an increased accessibility of these tumour cells for killing by NK-cells.

CONCLUSION

We demonstrated the highly efficient anti-tumour activity of AEZS-126 in in vitro models of ovarian cancer. Due to the good anti-tumour activity and the expected increase in NK-cell mediated killing even of platinum resistant tumour cells, AEZS-126 seems to be a promising candidate for clinical testing in ovarian cancer.

The small molecule NSC676914A is cytotoxic and differentially affects NFκB signaling in ovarian cancer cells and HEK293 cells

Background

The small molecule NSC676914A was previously identified as an NF-κB inhibitor in TPA-stimulated HEK293 cells (Mol Can Ther 8:571-581, 2009). We hypothesized that this effect would also be seen in ovarian cancer cells, and serve as its mechanism of cytotoxicity. OVCAR3 and HEK293 cell lines stably containing a NF-κB luciferase reporter gene were generated.

Methods

Levels of NF-κB activity were assessed by luciferase reporter assays, after stimulation with LPA, LPS, TPA, and TNFα, in the presence or absence of a known NF-κB inhibitor or NSC676914A, and cytotoxicity was measured.

Results

NSC676914A was toxic to both OVCAR3 and HEK293 cells. We also investigated the cytotoxicity of NSC676914A on a panel of lymphoma cell lines with well characterized mutations previously shown to determine sensitivity or resistance to NF-κB inhibition. The compound did not show predicted patterns of effects on NF-κB activity in either lymphoma, ovarian or HEK293 cell lines. In HEK293 cells, the small molecule inhibited NF-κB when cells were stimulated, while in OVCAR3 cells it only partially inhibited NF-κB. Interestingly, we observed rescue of cell death with ROS inhibition.

Conclusions

The current study suggests that the effect of NSC676914A on NF-κB depends on cell type and the manner in which the pathway is stimulated. Furthermore, as it is similarly toxic to lymphoma, OVCAR3 and HEK293 cells, NSC676914A shows promising NF-κB-independent anti-cancer activity in ovarian tumor cells.

Estrogen receptor expression and increased risk of lymphovascular space invasion in high-grade serous ovarian carcinoma

OBJECTIVE

Recent studies have demonstrated that lymphovascular space invasion (LVSI) is associated with increased risk of hematogenous and lymphatic metastasis and poor clinical outcome of women with epithelial ovarian cancer. Given the suspected role of estrogen in promoting ovarian cancer metastasis, we examined potential links between estrogen receptor and LVSI in high-grade serous ovarian carcinoma.

METHODS

Tumoral expression of ER, PR, p53, MDR1, EGFR, HER2, DNA ploidy, and S-phase fraction was examined for 121 cases of stage I-IV high-grade serous ovarian carcinoma samples obtained at primary cytoreductive surgery. Biomarker expression was correlated to LVSI and survival outcomes.

RESULTS

LVSI was observed in 101 (83.5%) of all cases. Immunohistochemistry of tested biomarkers showed ER (86.7%) to be the most commonly expressed followed by p53 (71.4%), HER2 (68.3%), EGFR (52.1%), MDR-1 (14.3%), and PR (8.9%). ER expression was positively correlated to PR expression (r=0.31, p=0.001). LVSI was only correlated with ER (odds ratio 6.27, 95%CI 1.93-20.4, p=0.002) but not with other biomarkers. In multivariate analysis, ER remained significantly associated with LVSI (p=0.039). LVSI remained a significant prognostic factor for decreased progression-free survival (HR 3.01, 95%CI 1.54-5.88, p=0.001) and overall survival (HR 2.69, 95%CI 1.18-6.23, p=0.021) while ER-expression did not remain as a significant variable in multivariate analysis.

CONCLUSION

Our data demonstrated that estrogen receptor was positively correlated with LVSI that was an independent prognostic indicator of poor survival outcomes of high-grade serous ovarian carcinoma. This study emphasizes the importance of estrogen pathway in promoting lymphatic or vascular spread of high-grade serous ovarian carcinoma.

Reversing Platinum Resistance in High-Grade Serous Ovarian Carcinoma: Targeting BRCA and the Homologous Recombination System

Resistance to platinum chemotherapy is one of the main factors driving ovarian cancer mortality, and overcoming platinum resistance is considered one of the greatest challenges in ovarian cancer research. Genetic and functional evidence points to the homologous recombination (HR) DNA repair system, and BRCA1 and BRCA2 in particular, as main determinants of response to platinum therapy. BRCA-mutant ovarian cancers are especially sensitive to platinum, associated with better survival, and amenable to poly ADP ribose polymerase inhibitor treatment. Here, we discuss a therapeutic concept that seeks to disrupt HR capacity via targeting of BRCA1 and BRCA2 functionality in order to reverse platinum resistance in BRCA-proficient high-grade serous ovarian cancers (HGSOC). We review the molecular signaling pathways that converge on BRCA1 and BRCA2, their activation status in ovarian cancer, and therapeutic options to modulate BRCA function. Several recent publications demonstrate efficient chemosensitization of BRCA-proficient cancers by combining targeted therapy with standard platinum-based agents. Due to its inherent genomic heterogeneity, molecularly defined subgroups of HGSOC may require different approaches. We seek to provide an overview of available agents and their potential use to reverse platinum resistance by inhibiting the HR system, either directly or indirectly, by targeting oncogenic activators of HR.

Reversing Platinum Resistance in High-Grade Serous Ovarian Carcinoma: Targeting BRCA and the Homologous Recombination System

Resistance to platinum chemotherapy is one of the main factors driving ovarian cancer mortality, and overcoming platinum resistance is considered one of the greatest challenges in ovarian cancer research. Genetic and functional evidence points to the homologous recombination (HR) DNA repair system, and BRCA1 and BRCA2 in particular, as main determinants of response to platinum therapy. BRCA-mutant ovarian cancers are especially sensitive to platinum, associated with better survival, and amenable to poly ADP ribose polymerase inhibitor treatment. Here, we discuss a therapeutic concept that seeks to disrupt HR capacity via targeting of BRCA1 and BRCA2 functionality in order to reverse platinum resistance in BRCA-proficient high-grade serous ovarian cancers (HGSOC). We review the molecular signaling pathways that converge on BRCA1 and BRCA2, their activation status in ovarian cancer, and therapeutic options to modulate BRCA function. Several recent publications demonstrate efficient chemosensitization of BRCA-proficient cancers by combining targeted therapy with standard platinum-based agents. Due to its inherent genomic heterogeneity, molecularly defined subgroups of HGSOC may require different approaches. We seek to provide an overview of available agents and their potential use to reverse platinum resistance by inhibiting the HR system, either directly or indirectly, by targeting oncogenic activators of HR.

Reversing Platinum Resistance in High-Grade Serous Ovarian Carcinoma: Targeting BRCA and the Homologous Recombination System

Resistance to platinum chemotherapy is one of the main factors driving ovarian cancer mortality, and overcoming platinum resistance is considered one of the greatest challenges in ovarian cancer research. Genetic and functional evidence points to the homologous recombination (HR) DNA repair system, and BRCA1 and BRCA2 in particular, as main determinants of response to platinum therapy. BRCA-mutant ovarian cancers are especially sensitive to platinum, associated with better survival, and amenable to poly ADP ribose polymerase inhibitor treatment. Here, we discuss a therapeutic concept that seeks to disrupt HR capacity via targeting of BRCA1 and BRCA2 functionality in order to reverse platinum resistance in BRCA-proficient high-grade serous ovarian cancers (HGSOC). We review the molecular signaling pathways that converge on BRCA1 and BRCA2, their activation status in ovarian cancer, and therapeutic options to modulate BRCA function. Several recent publications demonstrate efficient chemosensitization of BRCA-proficient cancers by combining targeted therapy with standard platinum-based agents. Due to its inherent genomic heterogeneity, molecularly defined subgroups of HGSOC may require different approaches. We seek to provide an overview of available agents and their potential use to reverse platinum resistance by inhibiting the HR system, either directly or indirectly, by targeting oncogenic activators of HR.

Myriocin induces apoptotic lung cancer cell death via activation of DR4 pathway

It has been known that myriocin inhibits melanoma growth. However, the effects and action mechanisms of myriocin on lung cancer cell growth have not been reported. In this study, we examined whether myriocin isolated from Mycelia sterilia inhibits cell growth of lung cancer cells (A549 and NCI-H460) as well as possible signaling pathways involved in cell growth inhibition. Different concentrations of myriocin inhibited the growth of lung cancer cells through the induction of apoptotic cell death. Consistent with cancer cell growth inhibition, myriocin induced the expression of death receptors (DRs) as well as p-JNK and p-p38 in both cell lines. Moreover, the combination of myriocin with DR4 ligand TRAIL, and other well known anti-tumor drugs (docetaxel and cisplatin) synergistically inhibited cancer cell growth, and induced DR4 expression. These results showed that myriocin inhibits lung cancer cells growth through apoptosis via the activation of DR4 pathways, and enhanced anti-cancer effects with well known drugs. Thus, our study indicates that myriocin could be effective for lung cancer cells as an anti-cancer drug and/or a conjunction agent with well known anti-cancers.

Platelet-derived growth factor receptor alpha (PDGFRα) targeting and relevant biomarkers in ovarian carcinoma

OBJECTIVE

Platelet-derived growth factor receptor alpha (PDGFRα) is believed to be associated with cell survival. We examined (i) whether PDGFRα blockade enhances the antitumor activity of taxanes in ovarian carcinoma and (ii) potential biomarkers of response to anti-PDGFRα therapy.

METHODS

PDGFRα expression in 176 ovarian carcinomas was evaluated with tissue microarray and correlated to survival outcome. Human-specific monoclonal antibody to PDGFRα (IMC-3G3) was used for in vitro and in vivo experiments with or without docetaxel. Gene microarrays and reverse-phase protein arrays with pathway analyses were performed to identify potential predictive biomarkers.

RESULTS

When compared to low or no PDGFRα expression, increased PDGFRα expression was associated with significantly poorer overall survival of patients with ovarian cancer (P=0.014). Although treatment with IMC-3G3 alone did not affect cell viability or increase apoptosis, concurrent use of IMC-3G3 with docetaxel significantly enhanced sensitization to docetaxel and apoptosis. In an orthotopic mouse model, IMC-3G3 monotherapy had no significant antitumor effects in SKOV3-ip1 (low PDGFRα expression), but showed significant antitumor effects in HeyA8-MDR (high PDGFRα expression). Concurrent use of IMC-3G3 with docetaxel, compared with use of docetaxel alone, significantly reduced tumor weight in all tested cell lines. In protein ontology, the EGFR and AKT pathways were downregulated by IMC-3G3 therapy. MAPK and CCNB1 were downregulated only in the HeyA8-MDR model.

CONCLUSION

These data identify IMC-3G3 as an attractive therapeutic strategy and identify potential predictive markers for further development.

Exploratory study of carboplatin plus the copper-lowering agent trientine in patients with advanced malignancies

PURPOSE

Preclinical data showed that trientine, a copper-lowering agent, re-sensitized cancer cells to carboplatin through enhanced human copper transporter 1 (hCtr1) -mediated platinum uptake.

EXPERIMENTAL DESIGN

We studied carboplatin and trientine in patients (n = 55; 45 who had failed platinum) with advanced malignancies (Phase I, modified 3 + 3 design).

RESULTS

The most common cancers were head and neck (n = 13), non-small cell lung (n = 10) and epithelial ovarian (n = 8). The median number of prior regimens was four. No dose-limiting toxicity or treatment-related deaths were observed at doses up to carboplatin AUC 6 given with trientine. Eight patients achieved stable disease (SD) ≥ 6 months (six platinum failures) and one patient with platinum-resistant ovarian cancer, partial response (PR) (total SD ≥ 6 months/PR = 9, 16.4 %). The mean nadir serum copper level in the nine patients with SD ≥ 6 months/PR was 0.55 μg/mL (95 % CI, 0.34-0.75) versus 1.22 μg/mL (95 % CI, 1.02-1.42) (p < 0.001) in 38 tested patients with progression. In patients who maintained their ceruloplasmin (major copper-carrying protein) levels at 5-15 mg/dL (n = 9), the median progression-free and overall survivals were 9.2 and 15.2 months versus 1.9 (p = 0.001) and 5.7 months (p = 0.033) in patients who did not (n = 38), respectively.

CONCLUSIONS

The combination of a copper-lowering agent with carboplatin was well tolerated and associated with antitumor activity, especially in patients in whom copper and/or ceruloplasmin levels were lowered. Further investigation of this strategy for reversing platinum resistance is warranted.

Gemcitabine eliminates double minute chromosomes from human ovarian cancer cells

Double minute chromosomes are cytogenetic manifestations of gene amplification frequently seen in cancer cells. Genes amplified on double minute chromosomes include oncogenes and multi-drug resistant genes. These genes encode proteins which contribute to cancer formation, cancer progression, and development of resistance to drugs used in cancer treatment. Elimination of double minute chromosomes, and therefore genes amplified on them, is an effective way to decrease the malignancy of cancer cells. We investigated the effectiveness of a cancer drug, gemcitabine, on the loss of double minute chromosomes from the ovarian cancer cell line UACC-1598. Gemcitabine is able to decrease the number of double minute chromosomes in cells at a 7500X lower concentration than the commonly used cancer drug hydroxyurea. Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment. Gemcitabine, even at a low nanomolar concentration, is able to cause DNA damage. The selective incorporation of double minutes chromatin and γ-H2AX signals into micronuclei provides a strong link between DNA damage and the loss of double minute chromosomes from gemcitabine treated cells. Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion. Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.

Gemcitabine-oxaliplatin (GEMOX) as salvage treatment in pretreated epithelial ovarian cancer patients

Background

Currently, no clearly superior management strategy exists for recurrent, platinum-resistant ovarian cancer. We tested the efficacy and safety of gemcitabine combined with oxaliplatin (GEMOX) in a multicentre phase II clinical trial.

Methods

Forty one patients with recurrent, platinum-resistant ovarian cancer were enrolled. Prior to study entry, all the participants had received at least one platinum-based regimen. Gemcitabine was administered at 1000 mg/m² as protracted infusion (100 min) on day 1, and oxaliplatin at the dose of 100 mg/m² on day 2 in a 2 hour infusion. Cycles were repeated every two weeks.

Results

We observed an overall response rate of 37% [95% Confidence Interval (CI), 22.3–51.7]. Objective responses plus disease stabilization (clinical benefit) occurred in 78% of patients. Median progression-free survival was 6.8 months (95% CI, 5.8–7.8), and median overall survival was 16.5 months (95% CI, 12.2–20.8). Median time to self-reported symptom relief, which was described by 22 out of 27 symptomatic patients (81.5%), was 4 weeks (range, 2–8). Grade 4 neutropenia and febrile neutropenia were observed in 2 (5%) and 1 (2.5%) patients, while grade 3 anemia was encountered in 2 (5%) patients, respectively. The most common adverse effects of any grade were gastrointestinal symptoms, fatigue and neutropenia. Nine patients (22%) experienced mild allergic reaction to oxaliplatin, with no treatment discontinuation.

Conclusions

In our cohort of recurrent, platinum-resistant ovarian cancer patients, GEMOX showed encouraging activity and manageable toxicity. Under circumstances requiring a rapid disease control, this combination regimen may offer a particularly viable option, particularly in heavily pretreated patients.

Complete remission of platinum-refractory primary Fallopian tube carcinoma with third-line gemcitabine plus cisplatin: A case report and review of the literature

Primary Fallopian tube carcinoma (PFTC) is a rare but highly aggressive disease. Currently, treatments are similar to those used in epithelial ovarian carcinoma (EOC), however, there are distinct differences between the two diseases. PFTC tends to recur in the retroperitoneal nodes and distant sites more often than EOC. Limited literature with regard to effective agents in platinum-resistant and -refractory (Pt-R) disease exists, particularly after two lines of consecutive treatment. In this case report, a 47-year-old female with PFTC exhibited recurrence in the liver after postoperative chemotherapy. The patient received paclitaxel and cisplatin combination as first-line chemotherapy and topotecan as a second-line treatment, which is considered platinum-refractory. After the second-line treatment failed, this patient received a gemcitabine plus cisplatin combination as third-line chemotherapy for a total of 6 cycles. The liver metastases regressed rapidly and completely. The patient's progression-free survival (PFS) was 10 months and overall survival (OS) was 45 months. In conclusion, gemcitabine and cisplatin combination is an effective regimen for refractory PFTC even after the failure of two previous lines of consecutive chemotherapy and this warrants further independent investigation.

Immune escape of AKT overexpressing ovarian cancer cells

Platinum-resistance is the most crucial problem for treatment of ovarian cancer. There is a clinical need for new treatment strategies which overcome platinum resistance. As survival is strongly influenced by immunological parameters, immunotherapeutic strategies appear promising. Therefore a better understanding of the interaction between ovarian tumour cells and cells of the immune system is a necessary prerequisite. In the present study we aimed to enlighten the interactions between platinum resistant and platinum sensitive ovarian cancer cells and natural-killer (NK)-cells. Modified FATAL assay was used for determining the killing efficiency of NK-cells for the parental A2780 cells and the cis-platinum resistant A2780cis human ovarian cancer cells. Expression of pro- and anti-apoptotic genes as well as ligands involved in NK-cell receptor recognition were analysed by RT-PCR and flow cytometric analysis. The efficiency of NK mediated cell lysis differs between A2780 cells and the cis-platinum-resistant A2780cis cells. A2780cis cells are less accessible for NK-cell mediated killing. Based on this observation we characterized the molecular basis for resistance mechanisms. Besides an increase in anti-apoptotic genes (especially CIAP-1 and -2) that probably render A2780cis cells more resistant against apoptosis an increased amount of soluble MICA/B seems to be responsible for the lower killing rate of platinum-resistant A2780cis cells compared to their parental A2780 cells.

Eradication of Human Ovarian Cancer Cells by Transgenic Expression of Recombinant DNASE1, DNASE1L3, DNASE2, and DFFB Controlled by EGFR Promoter: Novel Strategy for Targeted Therapy of Cancer

Introduction

Ovarian cancer is the most deadly among all gynecological cancers. Patients undergoing systemic therapies of advanced ovarian cancers suffer from horrendous side effects. Cancer survivors and their offspring suffer from iatrogenic consequences of systemic therapies: genetic mutations. The ultimate goal of our work is development of therapies, which selectively and completely eliminate cancer cells, but do not harm healthy cells. An important consideration for attaining this goal is the fact that ovarian cancer cells over-express EGFR or its mutants, what becomes the factor discriminating them from healthy cells - a potential facilitator of personalized therapy.

Specific aim

The specific aim of this project was threefold: (1) to bioengineer suicide genes’ carrying vectors guided by synthetic antibodies for EGFRvIII and EGFR; (2) to genetically engineer DNA constructs for the human, recombinant DNASE1, DNASE1L3, DNASE2, and DFFB controlled by the EGFR promoter; (3) to selectively eradicate ovarian cancer cells by intranuclear targeting of the transgenically expressed recombinant DNases.

Methods

Synthetic antibodies for EGFR and EGFRvIII were selected from the human library and used to bioengineer biotag-guided transgenes’ vectors. Coding sequences for the human DNASE1, DNASE1L3, DNASE2, DFFB controlled by the EGFR promoter were amplified from the human cDNA and genetically engineered into the plasmid constructs also coding for the fusions with NLS and GFP. The vectors carrying transgenes for the DNases were delivered in vitro into human ovarian cancer cells from ascites and cultures.

Results

Synthetic antibody guided vectors delivered the transgenes for the recombinant DNases efficiently into the ovarian cancer cells. Transgenic expression and nuclear targeting of the DNases in those cells resulted in destruction of their genomes and led to their death, as validated by labeling with the molecular death tags. In healthy cells, which did not over-express EGFR, no changes were recorded.

Conclusion

Targeted expression of the recombinant DNASE1, DNASE1L3, DNASE2, DFFB in the ovarian cancers in vitro resulted in their complete eradication, but had no effects upon the healthy cells. This novel therapeutic strategy has a potential for streamlining it into in vivo trials, as personalized, targeted therapy of ovarian and other cancers.

Downregulation of AKT reverses platinum resistance of human ovarian cancers in vitro

Platinum resistance is the most crucial problem for treatment of ovarian cancer. Increasing evidence points towards AKT overexpression as a mechanistic reason for this clinical condition. The present study evaluates the effect of overexpression and downregulation of AKT on the sensitivity to cisplatin in a platinum-resistant human ovarian cancer cell line and the corresponding platinum-sensitive parental cell line. A2780 and A2780cis ovarian cancer cell lines were stably transfected with an AKT-sense and AKT-antisense plasmid. Successful transfection was evaluated by western blot analysis. Cytotoxic effects of cisplatin were evaluated by metabolic (MTT) and clonogenicity assays as well as by FACS analysis. AKT overexpression (confirmed by western blotting) converted platinum-sensitive A2780 into platinum-resistant cells as shown by MTT assay. Importantly, platinum resistance of A2780cis cells could be reversed by downregulation of AKT, as demonstrated by MTT and clonogenicity assays and FACS analysis. Our data provide strong evidence that cisplatin resistance in ovarian cancer is mediated by AKT overexpression and can be overcome by AKT downregulation, thus, providing a rationale for clinical phase II/III studies combining AKT inhibitors with cisplatin.

Withaferin A synergizes the therapeutic effect of doxorubicin through ROS-mediated autophagy in ovarian cancer

Application of doxorubicin (Dox) for the treatment of cancer is restricted due to its severe side effects. We used combination strategy by combining doxorubicin (Dox) with withaferin A (WFA) to minimize the ill effects of Dox. Treatment of various epithelial ovarian cancer cell lines (A2780, A2780/CP70 and CaOV3) with combination of WFA and Dox (WFA/DOX) showed a time- and dose-dependent synergistic effect on inhibition of cell proliferation and induction of cell death, thus reducing the dosage requirement of Dox. Combination treatment resulted in a significant enhancement of ROS production resulting in immense DNA damage, induction of autophagy analyzed by transmission electron microscope and increase in expression of autophagy marker LC3B, and culminated in cell death analyzed by cleaved caspase 3. We validated combination therapy on tumor growth using an in vitro 3Dimension (3D) tumor model and the more classic in vivo xenograft model of ovarian cancer. Both tumor models showed a 70 to 80% reduction in tumor growth compared to control or animals treated with WFA or Dox alone. Immunohistochemical analysis of the tumor tissues from animals treated with WFA/Dox combination showed a significant reduction in cell proliferation and formation of microvessels accompanied by increased in LC3B level, cleaved caspase 3, and DNA damage. Taken together, our data suggest that combining WFA with Dox decreases the dosage requirement of Dox, therefore, minimizing/eliminating the severe side effects associated with high doses of DOX, suggesting the application of this combination strategy for the treatment of ovarian and other cancers with no or minimum side effects.

Significance of perioperative infection in survival of patients with ovarian cancer

OBJECTIVES

Perioperative infectious diseases comprise some of the most common causes of surgical mortality in women with ovarian cancer. This study was aimed to evaluate the significance of perioperative infections in survival of patients with ovarian cancer.

METHODS

Patients who underwent primary cytoreductive surgery were included in the analysis (n = 276). The enumeration and speciation of pathogens, antimicrobial agents used, and sensitivity assay results were culled from medical records and correlated to clinicopathologic demographics and survival outcomes. Perioperative infection was determined as a positive microbiology result obtained within a 6-week postoperative period.

RESULTS

The incidence of perioperative infection was 15.9% (common sites: urinary tract, 57.3%, and surgical wound, 21.4%). Commonly isolated pathogens were Enterococcus species (22.4%) and Escherichia coli (19.4%) in urinary tract infection, and Bacteroides fragilis, E. coli, and Klebsiella pneumoniae (all, 16%) in surgical wound infection. Imipenem represents one of the least resistant antimicrobial agents commonly seen in urinary tract and surgical wound infections in our institution. Perioperative infection was associated with diabetes, serous histology, lymph node metastasis, bowel resection, decreased bicarbonate, and elevated serum urea nitrogen in multivariate analysis. Perioperative infections were associated with increased surgical mortality, delay in chemotherapy treatment, decreased chemotherapy response, shorter progression-free survival (median time, 8.4 vs 17.6 months; P < 0.001), and decreased overall survival (29.0 vs 51.8 months; P = 0.011). Multivariate analysis showed that perioperative infections other than urinary tract infection remained a significant risk factor for decreased survival (progression-free survival, P = 0.02; and overall survival, P = 0.019).

CONCLUSION

Perioperative infectious disease comprises an independent risk factor for survival of patients with ovarian cancer.

Synergistic cytotoxic action of cisplatin and withaferin A on ovarian cancer cell lines

Cisplatin derivatives are used as the mainline treatment of ovarian cancer, despite their severe side effects and development of resistance. We developed a novel combination therapy by combining cisplatin with withaferin A. Treatment of ovarian cancer cell lines with combination therapy acted synergistically to induce cell death, thus required a lower dose of cisplatin to achieve the same therapeutic effect. WFA and cisplatin combination induced cell death through the generation of reactive oxygen species (ROS) for WFA, while DNA damage for cisplatin, suggesting that cisplatin binds directly to DNA to form adducts while WFA indirectly damages DNA through ROS generation. Our results for the first time suggest that combining low dose of cisplatin with suboptimal dose of WFA can serve as a potential combination therapy for the treatment of ovarian cancer with the potential to minimize/eliminate the side effects associated with high doses of cisplatin.

Overcoming platinum resistance through the use of a copper-lowering agent

Low levels of human copper transporter 1 (hCtr1) mRNA are associated with a shorter progression-free survival after platinum-based therapy. Pretreatment with a copper-lowering agent such as trientine enhanced hCtr1-mediated platinum uptake. Therefore, we conducted a pilot study (NCT01178112) of carboplatin and trientine with the goal of resensitizing patients with advanced cancer to platinum chemotherapy. This case report reviews the outcomes of 5 patients with platinum-resistant high-grade epithelial ovarian cancer enrolled on the study to date. Overall, they tolerated treatment well. Severe adverse events that occurred in 2 patients were myelosuppression, notably anemia requiring transfusion. Dose-limiting toxicity was not observed within the first 28 days (cycle 1). After 2 cycles of therapy, partial remission was achieved in 1 patient (10+ months), stable disease in 3 patients (2, 3.5+, and 5 months, respectively), and 1 patient had progressive disease. These cases provide preliminary clinical evidence that the role of decreasing copper levels in reversing platinum resistance merits additional clinical investigation. Evaluation of this novel strategy is warranted in larger studies to assess the efficacy of this approach for treating platinum-resistant advanced epithelial ovarian cancer in patients with high copper levels.

Patient-reported symptoms and survival in ovarian cancer

OBJECTIVE

While the development of an index of clinical symptoms to use for the detection and diagnosis of ovarian cancer is under active investigation, the role of clinical symptoms in survival after the initial diagnosis is poorly understood. The aim of this study was to correlate the type and extent of clinical symptoms with survival outcomes in ovarian cancer.

METHODS

Medical records of 276 cases of primary epithelial ovarian, fallopian tube, and peritoneal cancers were evaluated. Thirty-one symptoms in 5 categories were cataloged. The significance of clinical symptoms in progression-free survival (PFS) and overall survival (OS) was evaluated.

RESULTS

Overall, 93.5% of ovarian cancer patients expressed at least 1 symptom at the time of initial diagnosis. The 3 most common symptoms were abdominal pain (40.6%), increased abdominal size (33.7%), and bloating (21.7%). In survival analysis, weight loss (16.3%), nausea/vomiting (13.4%), and lower extremity edema (6.5%) were significantly associated with both decreased PFS and OS (all, P < 0.05). In multivariate analysis, lower extremity edema remained the strongest significant symptom, associated with increased surgical mortality rate, decreased response rate to adjuvant chemotherapy after primary cytoreductive surgery, and diminished survival outcomes (median PFS, 4.9 vs 15.3 months, P < 0.0001; and median OS, 5.9 vs 49.1 months, P < 0.001). Multiple symptoms were associated with poor survival outcomes (individual number of symptom ≤1 vs 2 vs ≥3; median PFS, 26.8 vs 17.4 vs 11.7 months [P < 0.001]; and median OS, 70 vs 41.6 vs 37.2 months [P < 0.001]).

CONCLUSIONS

Lower extremity edema at initial diagnosis is a strong prognostic indicator of ovarian cancer patient.

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.

Phase I/II study of sagopilone (ZK-EPO) plus carboplatin in women with recurrent platinum-sensitive ovarian cancer

BACKGROUND

Sagopilone is the first fully synthetic epothilone in clinical development and has demonstrated promising preclinical activity. This phase I/II, prospective, open-label trial investigated the efficacy and safety of sagopilone plus carboplatin in patients with recurrent platinum-sensitive ovarian cancer (OC).

METHODS

In phase I (dose-escalation stage), patients with OC recurring at least 6 months after platinum-containing chemotherapy received 3-h infusions of sagopilone (initial dose of 12 mg m(-2)) followed by carboplatin every 3 weeks, for 2-6 treatment courses. Patients enrolled in phase II received 3-h infusions of 16 mg m(-2) sagopilone. Efficacy was assessed using modified Response Evaluation Criteria in Solid Tumors (modRECIST) and Gynecologic Cancer InterGroup CA125 criteria. The safety and tolerability of sagopilone were also evaluated.

RESULTS

In all, 45 patients received sagopilone at 12 mg m(-2) or 16 mg m(-2). There were 29 confirmed tumour responses (21 modRECIST and 8 CA125) across both treatment groups, indicating that the primary objective of the study was reached. The main adverse events (AEs) reported were peripheral neuropathy (75.6%), fatigue (71.1%) and nausea (64.4%). Grade ≥3 AEs occurred in 35 patients (77.8%). No deaths related to the study drug were reported.

CONCLUSION

Sagopilone in combination with carboplatin was effective and toxicities were manageable in patients with recurrent platinum-sensitive OC.

Targeting SRC in mucinous ovarian carcinoma

PURPOSE

Mucinous ovarian carcinomas have a distinct clinical pattern compared with other subtypes of ovarian carcinoma. Here, we evaluated (i) stage-specific clinical significance of mucinous ovarian carcinomas in a large cohort and (ii) the functional role of Src kinase in preclinical models of mucinous ovarian carcinoma.

EXPERIMENTAL DESIGN

A total of 1,302 ovarian cancer patients including 122 (9.4%) cases of mucinous carcinoma were evaluated for survival analyses. Biological effects of Src kinase inhibition were tested using dasatinib-based therapy in a novel orthotopic mucinous ovarian cancer model (RMUG-S-ip2).

RESULTS

Patients with advanced-stage mucinous ovarian cancer had significantly worse survival than those with serous histology: median overall survival, 1.67 versus 3.41 years, P = 0.002; median survival time after recurrence of 0.53 versus 1.66 years, P < 0.0001. Among multiple ovarian cancer cell lines, RMUG-S-ip2 mucinous ovarian cancer cells showed the highest Src kinase activity. Moreover, oxaliplatin treatment induced phosphorylation of Src kinase. This induced activity by oxaliplatin therapy was inhibited by concurrent administration of dasatinib. Targeting Src with dasatinib in vivo showed significant antitumor effects in the RMUG-S-ip2 model but not in the serous ovarian carcinoma (SKOV3-TR) model. Combination therapy of oxaliplatin with dasatinib further showed significant effects on reducing cell viability, increasing apoptosis, and in vivo antitumor effects in the RMUG-S-ip2 model.

CONCLUSIONS

Our results suggest that poor survival of women with mucinous ovarian carcinoma is associated with resistance to cytotoxic therapy. Targeting Src kinase with a combination of dasatinib and oxaliplatin may be an attractive approach for this disease.