Recent advances in the treatment of epithelial ovarian cancer

Microphysiological systems as models for immunologically 'cold' tumors

The tumor microenvironment (TME) is a diverse milieu of cells including cancerous and non-cancerous cells such as fibroblasts, pericytes, endothelial cells and immune cells. The intricate cellular interactions within the TME hold a central role in shaping the dynamics of cancer progression, influencing pivotal aspects such as tumor initiation, growth, invasion, response to therapeutic interventions, and the emergence of drug resistance. In immunologically 'cold' tumors, the TME is marked by a scarcity of infiltrating immune cells, limited antigen presentation in the absence of potent immune-stimulating signals, and an abundance of immunosuppressive factors. While strategies targeting the TME as a therapeutic avenue in 'cold' tumors have emerged, there is a pressing need for novel approaches that faithfully replicate the complex cellular and non-cellular interactions in order to develop targeted therapies that can effectively stimulate immune responses and improve therapeutic outcomes in patients. Microfluidic devices offer distinct advantages over traditional in vitro 3D co-culture models and in vivo animal models, as they better recapitulate key characteristics of the TME and allow for precise, controlled insights into the dynamic interplay between various immune, stromal and cancerous cell types at any timepoint. This review aims to underscore the pivotal role of microfluidic systems in advancing our understanding of the TME and presents current microfluidic model systems that aim to dissect tumor-stromal, tumor-immune and immune-stromal cellular interactions in various 'cold' tumors. Understanding the intricacies of the TME in 'cold' tumors is crucial for devising effective targeted therapies to reinvigorate immune responses and overcome the challenges of current immunotherapy approaches.

The Significance of Adaptation and Coping with Disease among Patients with Diagnosed Gynaecological Cancer in the Context of Disease Acceptance

Uterine/endometrial and ovarian tumours are among the most common gynaecological cancers. Adaptation to cancer encompasses a variety of complex behavioural, cognitive, and emotional processes. The purpose of mental adaptation is to alleviate emotional discomfort and regain mental stability. The aim of the study was to assess the influence of adaptation and coping with gynaecological cancer on the level of disease acceptance among the studied women. The study included 81 patients diagnosed with gynaecological cancer. Mental adaptation to cancer was measured using the Min-Mac scale, disease acceptance was measured using the AIS and the level of adaptation was measured using the CAPS. The average AIS score was 26.65 ± 8.85 points. Adaptation and coping methods did not vary significantly depending on the diagnosed type of cancer. The constructive style of fighting the disease prevailed (45.11 ± 6.01). The AIS scores correlated significantly and positively with the intensity of the constructive style of mental adaptation, and negatively with the intensity of the destructive style. The studied group of patients with gynaecological cancer displayed a moderate level of disease acceptance, the constructive style of adaptation was the most prevalent, and the location of the cancer did not have an effect on coping mechanisms.

Period Analysis of Intraracial Differences in Incidence and Survival Rates in Epithelial Ovarian Cancer

BACKGROUND

To explain the difference in the incidence and relative survival in a population-based cohort of women with epithelial ovarian cancer (EOC) postdiagnosis in the last forty years. EOC is the most common type of all ovarian cancers, but there is inadequate information about the variations related to long-term EOC survival.

METHODS

We acquired the incidence and relative survival rate data from the Surveillance, Epidemiology, and End Results (SEER) registries to analyze the epidemiological variations from 1974 to 2013 in EOC-affected individuals. The survival disparities in EOC-specific individuals due to age, race, and socioeconomic status (SES) were performed by Kaplan-Meier analysis. The Results. The overall incidence of EOC progressively declined to 9.0 per 100,000 from 11.4 in the last forty years. The median survival rate improved to 48 months in the first decade from a previous of 27 months in the fourth decade. The 5-year relative survival rate (RSR) increased to 44.3% that was previously 32.3% at the same time. However, between whites and blacks, an increase from 11 to 18 months was observed in the median survival differences. Between the low and high poverty groups, it was increased from 7 months to 12 months, respectively.

CONCLUSIONS

The incidence rate of RSR and EOC-specific individuals in the last forty years was improved. However, the survival rates among different races and SES differed over time.

Androgen/Androgen Receptor Signaling in Ovarian Cancer: Molecular Regulation and Therapeutic Potentials

Ovarian cancer (OVCA) arises from three cellular origins, namely surface epithelial cells, germ cells, and stromal cells. More than 85% of OVCAs are EOCs (epithelial ovarian carcinomas), which are the most lethal gynecological malignancies. Cancer stem/progenitor cells (CSPCs) are considered to be cancer promoters due to their capacity for unlimited self-renewal and drug resistance. Androgen receptor (AR) belongs to the nuclear receptor superfamily and can be activated through binding to its ligand androgens. Studies have reported an association between AR expression and EOC carcinogenesis, and AR is suggested to be involved in proliferation, migration/invasion, and stemness. In addition, alternative AR activating signals, including both ligand-dependent and ligand-independent, are involved in OVCA progression. Although some clinical trials have previously been conducted to evaluate the effects of anti-androgens in EOC, no significant results have been reported. In contrast, experimental studies evaluating the effects of anti-androgen or anti-AR reagents in AR-expressing EOC models have demonstrated positive results for suppressing disease progression. Since AR is involved in complex signaling pathways and may be expressed at various levels in OVCA, the aim of this article was to provide an overview of current studies and perspectives regarding the relevance of androgen/AR roles in OVCA.

Inferring Synergistic Drug Combinations Based on Symmetric Meta-Path in a Novel Heterogeneous Network

Combinatorial drug therapy is a promising way for treating cancers, which can reduce drug side effects and improve drug efficacy. However, due to the large-scale combinatorial space, it is difficult to quickly and effectively identify novel synergistic drug combinations for further implementing combinatorial drug therapy. The computational method of fusing multi-source knowledge is a time- and cost-efficient strategy to infer synergistic drug combinations for testing. However, for the existing computational methods of inferring synergistic drug combinations, it still remains a challenging to effectively combine multi-source information to achieve the desired results. Hence, in this study, we developed a novel Inference method of Synergistic Drug Combinations based on Symmetric Meta-Path (ISDCSMP), which can systematically and accurately prioritize synergistic drug combinations in a novel drug-target heterogeneous network integrating multi-source information. In the experiment, ISDCSMP outperformed the state-of-the-art methods in terms of AUC and precision on the benchmark dataset in five-fold cross validation. Moreover, we further illustrated performances of different ways for obtaining the combination coefficients, and analyzed the influences of the maximum meta-path length. The performances of various single meta-paths were described in five-fold cross validation. Finally, we confirmed the practical usefulness of ISDCSMP with the predicted novel synergistic drug combinations. The source code of ISDCSMP is available at https://github.com/KDDing/ISDCSMP.

Overexpression of long noncoding RNA PTPRG-AS1 is associated with poor prognosis in epithelial ovarian cancer

OBJECTIVE Long noncoding RNAs (lncRNAs) have been shown to play a critical role in tumor progression. Abnormal expression of LncRNA PTPRG antisense RNA 1 (PTPRG-AS1) has been reported in several tumors. Hence, we aimed to determine the expression and clinical significance of PTPRG-AS1 in epithelial ovarian cancer (EOC) patients. METHODS The expressions of PTPRG-AS1 were assessed in 184 pairs of EOC tumor specimens and adjacent normal tissues. The levels of target lncRNAs and GAPDH were examined using standard SYBR-Green methods. The relationships between the expressions of PTPRG-AS1 and the clinicopathological features were analyzed using the chi-square test. Multivariate analysis using the Cox proportional hazards model was performed to assess the prognostic value of PTPRG-AS1 in EOC patients. RESULTS We confirmed that the expressions of PTPRG-AS1 were distinctly higher in the EOC tissue compared with the adjacent non-tumor specimens (p < 0.01). Higher levels of PTPRG-AS1 in EOC patients were associated with advanced FIGO stage (p = 0.005), grade (p = 0.006), and distant metastasis (p = 0.005). Survival analyses revealed that patients with high expressions of PTPRG-AS1 had a distinctly decreased overall survival (p = 0.0029) and disease-free survival (p = 0.0009) compared with those with low expressions of PTPRG-AS1. Multivariate assays indicated that PTPRG-AS1 expression was an independent prognostic factor for both overall survival and disease-free survival in EOC (Both p < 0.05). CONCLUSIONS Our study suggests that PTPRG-AS1 may serve as a novel prognostic biomarker for EOC patients.

Increase Paclitaxel Sensitivity to Better Suppress Serous Epithelial Ovarian Cancer via Ablating Androgen Receptor/Aryl Hydrocarbon Receptor-ABCG2 Axis

Background: Epithelial ovarian cancer (EOC) is one of the most lethal gynecological malignancies and presents chemoresistance after chemotherapy treatment. Androgen receptor (AR) has been known to participate in proliferation. Yet the mechanisms of the resistance of this drug and its linkage to the AR remains unclear. Methods: To elucidate AR-related paclitaxel sensitivity, co-IP, luciferase reporter assay and ChIP assay were performed to identify that AR direct-regulated ABCG2 expression under paclitaxel treatment. IHC staining by AR antibody presented higher AR expression in serous-type patients than other types. AR degradation enhancer (ASC-J9) was used to examine paclitaxel-associated and paclitaxel-resistant cytotoxicity in vitro and in vivo. Results: We found AR/aryl hydrocarbon receptor (AhR)-mediates ABCG2 expression and leads to a change in paclitaxel cytotoxicity/sensitivity in EOC serous subtype cell lines. Molecular mechanism study showed that paclitaxel activated AR transactivity and bound to alternative ARE in the ABCG2 proximal promoter region. To identify AR as a potential therapeutic target, the ASC-J9 was used to re-sensitize paclitaxel-resistant EOC tumors upon paclitaxel treatment in vitro and in vivo. Conclusion: The results demonstrated that activation of AR transactivity beyond the androgen-associated biological effect. This novel AR mechanism explains that degradation of AR is the most effective therapeutic strategy for treating AR-positive EOC serous subtype.

Emerging Therapeutics to Overcome Chemoresistance in Epithelial Ovarian Cancer: A Mini-Review

Ovarian cancer is the fifth leading cause of cancer death among women and the most lethal gynecologic malignancy. One of the leading causes of death in high-grade serous ovarian cancer (HGSOC) is chemoresistant disease, which may present as intrinsic or acquired resistance to therapies. Here we discuss some of the known molecular mechanisms of chemoresistance that have been exhaustively investigated in chemoresistant ovarian cancer, including drug efflux pump multidrug resistance protein 1 (MDR1), the epithelial–mesenchymal transition, DNA damage and repair capacity. We also discuss novel therapeutics that may address some of the challenges in bringing approaches that target chemoresistant processes from bench to bedside. Some of these new therapies include novel drug delivery systems, targets that may halt adaptive changes in the tumor, exploitation of tumor mutations that leave cancer cells vulnerable to irreversible damage, and novel drugs that target ribosomal biogenesis, a process that may be uniquely different in cancer versus non-cancerous cells. Each of these approaches, or a combination of them, may provide a greater number of positive outcomes for a broader population of HGSOC patients.

Predictive value of XRCC1 and XRCC3 gene polymorphisms for risk of ovarian cancer death after chemotherapy

OBJECTIVE

To investigate any association between XRCC1 and XRCC3 polymorphisms and outcome of platinum-based chemotherapy in ovarian cancer patients.

METHODS

With a prospective study design was cases were consecutively collected from January 2005 to January 2007. All 310 included patients were followed-up until the end of January 2010. Genotyping of XRCC1 and XRCC3 polymorphisms was conducted by TaqMan Gene Expression assays.

RESULTS

A total of 191 patients died during follow-up. Our study showed a lower survival rate in XRCC1 399 Arg/Arg genotype than Gln/ Gln, with a significant increased risk of death (HR=1.69, 95%CI=1.07-2.78). Similarly, those carrying XRCC3 Thr/ Thr genotype had a increased risk as compare to the Met/Met genotype, with a HR (95% CI) of 1.90 (1.12-3.41). There was no significant association between XRCC1 Arg194Trp and XRCC1Arg280His gene polymorphisms and ovarian cancer death.

CONCLUSION

Our study demonstrates that polymorphisms in DNA repair genes have roles in the susceptibility and survival of ovarian cancer patients.

Comparative effectiveness of platinum-based chemotherapy versus taxane and other regimens for ovarian cancer

The aim was to compare the two most commonly recommended chemotherapy regimens (platinum-based chemotherapy and platinum-taxane combination) with non-platinum-based chemotherapy and those with no chemotherapy in a large nationwide and population-based cohort of patients with ovarian cancer with up to 17 years of follow-up. We studied 12,181 patients diagnosed with stages I-IV ovarian cancer at age ≥ 65 in 1991-2005 from the 16 areas of the United States. We also performed matched cohort analyses based on conditional probability of receiving platinum chemotherapy in 3,428 patients. In patients with early stage ovarian cancer, those who received platinum-taxane combination had the highest 5-year all-cause (62.5 %) and cancer-specific (65.1 %) survival rates, as compared to 51.5 and 63.7 % in those without chemotherapy. After adjusting for potential confounders, hazard ratios of all-cause mortality (0.66, 95 % CI 0.55-0.79) and cancer-specific mortality (0.74, 0.61-0.90) were significantly lower in patients receiving platinum-taxane combination as compared to those without chemotherapy. Among patients with late-stage ovarian cancer, risks of mortality were significantly reduced in patients who received both platinum and taxane (0.38, 0.36-0.41 for all-cause mortality; 0.40, 0.37-0.42 for cancer-specific mortality). Dose-response relationship appeared strong within each of the three chemotherapy regimens. These results and trends were almost identical in the matched cohort. Platinum-taxane combination chemotherapy and platinum-based chemotherapy without taxane were effective in prolonging survival with a significant dose-response relationship among patients with late-stage ovarian cancer. Among those with early stage tumors, platinum-taxane combination appeared more effective than other chemotherapy regimens.

Low dose histone deacetylase inhibitor, LBH589, potentiates anticancer effect of docetaxel in epithelial ovarian cancer via PI3K/Akt pathway in vitro

The purpose of this study was to investigate the effect of combination of LBH589 with docetaxel (DTX) on the growth and survival of epithelial ovarian cancer (EOC) cells in vitro and the possible mechanisms of chemo-sensitization of LBH589 in the combination treatment. The effect of LBH589 alone or in combination with DTX on four EOC cell lines (OVCAR-3, IGROV-1, A2780 and SKOV-3) was studied by MTT and clonogenic assays, acridine orange (AO)/ethidium bromide (EB) staining for apoptosis, Western blotting for apoptosis-related proteins, histone H3 and H4 proteins, DNA double strand break (DSB) repair marker and phosphorylation of Akt. LBH589 alone inhibited EOC cell proliferation in a time and dose-dependent manner. Low-dose of LBH589 (IC(20)) combined with DTX had an additive effect and greatly improved efficacy of DTX cell killing in EOC cells. Compared to DTX alone, the combination treatment with LBH589 and DTX induced more apoptosis and led to an increased and persistent DSB. Cell death following single or combined treatment was associated with the release of cytochrome c activity, increased caspase-3 (active) and PARP-1(cleaved), histone acetylation-related proteins and PI3k/Akt signaling pathway. Our results suggest that LBH589 enhances DTX-induced apoptosis in human EOC cells, and can be used in combination with DTX as an attractive strategy for treating human EOC.

Low-dose LBH589 increases the sensitivity of cisplatin to cisplatin-resistant ovarian cancer cells

OBJECTIVE

There is a need to develop alternative therapeutic strategies to overcome cisplatin-associated resistance in patients with ovarian cancer. Histone deacetylation (HDAC) associated with inactivation of genes has been implicated in the epigenetic silencing of tumor suppressor genes affecting critical biological activities in cancer cells and may be an important factor in acquired cisplatin-associated resistance. In this report, we tested a combination of cisplatin and LBH589 (histone deacetylation inhibitor) in cisplatin-resistant ovarian cancer cells to explore the reversal effect of cisplatin resistance and changes of gene expression.

MATERIALS AND METHODS

To detect the synergistic effects of antiproliferation between cisplatin and LBH589 in ovarian cancer cells, we performed a cell viability assay and a clonogenic assay. To investigate the differences of gene expression between cells treated by cisplatin alone and cotreated with cisplatin and LBH589, a microarray mRNA analysis was performed.

RESULTS

In the presence of low-dose LBH589, the inhibition concentration value of cisplatin for A2780-cp70 cells was much lower than with cisplatin treatment alone. Gene expression profiles identified that a total of 354 genes had been significantly upregulated and a total of 63 genes been downregulated with LBH589 cotreatment.

CONCLUSION

We hypothesized that combination of cisplatin and LBH589 can override cisplatin-associated resistance in ovarian cancer cells. These results provide initial evidence for testing this combination in clinical use.

Anti-MUC1 monoclonal antibody (C595) and docetaxel markedly reduce tumor burden and ascites, and prolong survival in an in vivo ovarian cancer model

MUC1 is associated with cellular transformation and tumorigenicity and is considered as an important tumor-associated antigen (TAA) for cancer therapy. We previously reported that anti-MUC1 monoclonal antibody C595 (MAb C595) plus docetaxel (DTX) increased efficacy of DTX alone and caused cultured human epithelial ovarian cancer (EOC) cells to undergo apoptosis. To further study the mechanisms of this combination-mediated apoptosis, we investigated the effectiveness of this combination therapy in vivo in an intraperitoneal (i.p.) EOC mouse model. OVCAR-3 cells were implanted intraperitoneally in female athymic nude mice and allowed to grow tumor and ascites. Mice were then treated with single MAb C595, DTX, combination test (MAb C595 and DTX), combination control (negative MAb IgG₃ and DTX) or vehicle control i.p for 3 weeks. Treated mice were killed 4 weeks post-treatment. Ascites volume, tumor weight, CA125 levels from ascites and survival of animals were assessed. The expression of MUC1, CD31, Ki-67, TUNEL and apoptotic proteins in tumor xenografts was evaluated by immunohistochemistry. MAb C595 alone inhibited i.p. tumor growth and ascites production in a dose-dependent manner but did not obviously prevent tumor development. However, combination test significantly reduced ascites volume, tumor growth and metastases, CA125 levels in ascites and improved survival of treated mice compared with single agent-treated mice, combination control or vehicle control-treated mice (P<0.05). The data was in a good agreement with that from cultured cells in vitro. The mechanisms behind the observed effects could be through targeting MUC1 antigens, inhibition of tumor angiogenesis, and induction of apoptosis. Our results suggest that this combination approach can effectively reduce tumor burden and ascites, prolong survival of animals through induction of tumor apoptosis and necrosis, and may provide a potential therapy for advanced metastatic EOC.

Octreotide enhances the sensitivity of the SKOV3/DDP ovarian cancer cell line to cisplatin chemotherapy in vitro

The present study aimed to investigate the effects of octreotide (OCT) on the reversal of resistance of cisplatin-resistant cancer cells and on enhancement of the cisplatin sensitivity of cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide method and flow cytometry were used to investigate the effect of cisplatin, OCT or the combination of these two compounds on the proliferation and apoptosis of SKOV3/DDP cells. Real-time, quantitative RT-PCR was used to detect the mRNA expression of SSTR2, MDR1, MRP2, GST-π and EGFR in SKOV3/DDP cells following OCT treatment. At the concentration of 2.5-20 μg/ml, OCT significantly reduced the IC(50) value (P<0.05) and promoted apoptosis (P<0.05) in the SKOV3/DDP cells in response to cisplatin. The synergistic effect of OCT and cisplatin on SKOV3/DDP cell proliferation was observed. SSTR2 was expressed on the SKOV3/DDP cell surface. OCT increased GST-π expression (P<0.05) and reduced MRP2 and EGFR expression (P<0.05) in a dose-dependent manner. However, it had no effect on the expression of MDR1 (P>0.05). It is suggested that OCT inhibits ovarian cancer proliferation and promotes apoptosis, via the cell surface expression of SSRT2, and reverses cisplatin resistance through the inhibition of MRP2 and EGFR expression.

Estrogen receptor alpha expression in ovarian cancer predicts longer overall survival

Estrogen as a potential factor of ovarian carcinogenesis, acts via two nuclear receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), but the cellular signal pathways involved are not completely clear so far. In this study we have described the expression of ERα, detected by immunocytochemistry in 11 ovarian carcinoma cell lines and by immunohistochemistry in 43 Federation Internationale des Gyneacologistes et Obstetristes stage III ovarian carcinoma specimens prepared before and after treatment with cisplatin-based schemes. For cisplatin resistance is a major obstacle in the treatment of ovarian carcinoma, analysis of cisplatin sensitivity in 11 ovarian carcinoma cell line was also performed. The strong nuclear ERα expression was only shown in the single A2780P cell line. Expression of ERα in tissue specimens did not reveal any correlations between histopathological parameters (histologic type and grading). We demonstrated a significant association with ERα expression in specimens from primary laparotomies (PL) and cause–specific survival. In the cases terminated by death of the patient, overall immunoreactivity score of ERα expression at PL was significantly lower than in surviving patients. In addition, Kaplan-Meier analysis revealed significantly shorter overall survival time and progression-free time in cases with lower immunoreactivity score of ERα expression at PL. Our findings support the hypothesis that aberrant hormone activity, by way of altered receptor expression, might be an important factor in the malignant transformation of ovarian cancer.

Microarray-Based Gene Expression Studies in Ovarian Cancer

Background

DNA microarray technology is a powerful genomic tool that has the potential to elucidate the relationship between clinical features of cancers and their underlying biological alterations.

Methods

We performed a systemic search in PubMed and Medline databases for recently published articles. The search terms used included “genome-wide,” “microarrays,” “ovarian cancer,” “prognosis” “gene expression profiling,” “molecular marker,” and “molecular biomarker.”

Results

Genome-wide expression profiling using DNA microarray technology has enhanced our understanding of the genes that influence ovarian cancer development, histopathologic subtype, progression, response to therapy, and overall survival.

Conclusions

Gene expression profiling has demonstrated its utility in ovarian cancer research. It is hoped that with technologic, statistical, and bioinformatic advances, the reliability and reproducibility of this technique will increase, spawning clinical applications that may enhance our understanding of the disease and our ability to care for patients in the future.

Effects of pharmacological concentrations of estrogens on growth of 3AO human ovarian cancer cells

During the past two decades, the knowledge of the molecular mechanism by which estrogens exert various functions in different tissues and organs has evolved rapidly. Recent reports demonstrated that estrogen could decrease the cell growth in several types of cancer cells, including ovarian cancer cells. Though experiments explored the possible mechanism of the inhibitory effect, the exact mechanism is responsible for the effect, which remains unclear. The ovary is the main source of the estrogen, estrogen receptor is expressed in several ovarian cell types, including ovarian surface epithelium, the tissue of origin of approximately 90% of the ovarian cancers. It was of great interest to analyze the effects of 17beta-estradiol (E2) on apoptosis of ovarian cancer cells, and the identification of E2-regulated specific genes involved in epithelial proliferation apoptosis, thus may be a clue for understanding the progression of ovarian cancer and for the design of new target therapies. To elucidate the mechanism involved, effects of pharmacological concentrations of estrogen were studied in human ovarian cancer cell line 3AO cells. Inhibition of cellular growth of 3AO cells was seen with E2 at concentrations higher than 0.1 micromol/L. The estrogen receptor inhibitor ICI 182780 cannot block the inhibitory effect of E2. It was surprising to find that ICI 182780 itself can inhibit the growth of 3AO cells, and had a collaborative effect with E2. The decreased cell growth induced by E2 was shown to be apoptosis as analyzed by flow cytometry. ERbeta was detected in the 3AO ovarian cancer cell line but not ERalpha. The expression of ERbeta was weak, which may partially explain why high but not low dose of E2 needed to induce the apoptosis of 3AO cells. We also observed that membrane impermeable E2, E2-BSA have lost growth inhibitory on 3AO cells, which excluded the membrane effect of E2 as previously reported by many investigators. The p38 kinase inhibitor, SB203580 were partially protected 3AO cells against growth inhibition by E2, while inhibitor of JNK, SP600125 enhanced cell death induced by E2. These results showed that MAPK is implicated in cellular processes involving apoptosis.

Chemotherapy drug response in ovarian cancer cells strictly depends on a cathepsin D-Bax activation loop

The ovarian cancer cell lines A2780 (wild-type p53) and NIHOVCAR3 (mutated p53) showed, respectively, sensitivity and resistance towards several chemotherapy drugs. We hypothesized that the two cell lines differ in their ability to activate the intrinsic death pathway and have, therefore, dissected the lysosome-mitochondrion signalling pathway by pharmacological inhibition or genetic manipulation of key regulators and executioners. Biochemical and morphological confocal fluorescence studies showed that: (1) In A2780 cells bcl-2 is expressed at an undetectable level, whereas Bax is expressed at a rather high level; by contrast, bcl-2 is highly expressed and Bax is expressed at extremely low levels in NIHOVCAR3 cells; (2) Chemotherapy treatment reduced the expression of bcl-2 in NIHOVCAR3 cells, yet these cells resisted to drug toxicity; (3) Cathepsin D (CD), not cathepsin B or L, mediates the activation of the mitochondrial intrinsic death pathway in A2780 cells; (4) Lysosome leakage and cytosolic relocation of CD occurs in the chemosensitive A2780 cells, not in the chemoresistant NIHOVCAR3 cells; (5) Bax is essential for the permeabilization of both lysosomes and mitochondria in A2780 cells exposed to chemotherapy drugs; (6) CD activity is mandatory for the oligomerization of Bax on both mitochondrial and lysosomal membranes; (7) Bax activation did not occur in the resistant NIHOVCAR3 cells despite their high content in CD. The present data are consistent with a model in which on treatment with a cytotoxic drug the activation of a CD-Bax loop leads to the generalized permeabilization of lysosomes and eventually of mitochondria, thus reaching the point of no return, and culminates with the activation of the caspase cascade. Our data also imply that dysfunctional permeabilization of lysosomes contributes to the development of chemoresistance.

ERCC5 is a novel biomarker of ovarian cancer prognosis

PURPOSE

To identify a biomarker of ovarian cancer response to chemotherapy. PATIENTS AND METHODS Study: participants had epithelial ovarian cancer treated with surgery followed by platinum-based chemotherapy. DNA and RNA were isolated from frozen tumors and normal DNA was isolated from matched peripheral blood. A whole-genome loss of heterozygosity (LOH) analysis was performed using a high-density oligonucleotide array. Candidate genomic areas that predicted enhanced response to chemotherapy were identified with Cox proportional hazards methods. Gene expression analyses were performed through microarray experiments. Candidate genes were tested for independent effects on survival using Cox proportional hazards models, Kaplan-Meier survival curves, and the log-rank test.

RESULTS

Using a whole-genome approach to study the molecular determinants of ovarian cancer response to platinum-based chemotherapy, we identified LOH of a 13q region to predict prolonged progression-free survival (PFS; hazard ratio, 0.23; P = .006). ERCC5 was identified as a candidate gene in this region because of its known function in the nucleotide excision repair pathway, the unique DNA repair pathway that removes platinum-DNA adducts. We found LOH of the ERCC5 gene locus and downregulation of ERCC5 gene expression to predict prolonged PFS. Integration of genomic and gene expression data shows a correlation between 13q LOH and ERCC5 gene downregulation.

CONCLUSION

ERCC5 is a novel biomarker of ovarian cancer prognosis and a potential therapeutic target of ovarian cancer response to platinum chemotherapy.

Ovarian tumor growth regression using a combination of vascular targeting agents anginex or topomimetic 0118 and the chemotherapeutic irofulven

Combination of chemotherapeutic agents and angiogenesis inhibitors is now commonly employed in the clinic to treat cancer. Here, we used angiostatic agents anginex and 0118, in combination with the chemotherapeutic irofulven, to treat human ovarian tumor xenografts in mice. General linear mixed models were used to statistically analyze tumor growth curves. Overall, combination of a low, non-toxic dose of irofulven with either angiogenesis inhibitor was more effective at inhibiting tumor growth than any of the single agent therapies. For example, the anginex/irofulven and 0118/irofulven combinations inhibited tumor growth relative to controls by 92% (p<0.0001) and 96% (p<0.0001), respectively, with the 0118/irofulven combinations yielding 100% complete responses. This study suggests that combination therapy of 0118 or anginex and irofulven may be highly effective in the clinical setting.

Ethnic differences in socioeconomic status, diagnosis, treatment, and survival among older women with epithelial ovarian cancer

The purpose of the study was to determine the ethnic disparities in socioeconomic status (SES) and in receiving definitive surgical treatment and adjuvant chemotherapy and to examine if these differences contribute to ethnic disparities in survival. We studied a population-based cohort of 5131 women diagnosed with epithelial ovarian cancer at age >or=65 between 1992 and 1999, identified from the Surveillance, Epidemiology and End Results-Medicare linked databases with up to 11 years of follow-up. The percentage of women diagnosed with epithelial ovarian cancer at advanced stage (stage III or IV) was 71.6% in Caucasians and 69.7% in African-Americans. Of these 4264 with stage IC-IV disease who are recommended for chemotherapy, fewer African-Americans received chemotherapy compared to Caucasians (50.2% versus 64.7%, P < 0.001). The risk of all-cause mortality in African-Americans was not significantly different from Caucasians (hazard ratio [HR] = 1.00, 95% CI = 0.88-1.13) after controlling for patient demographics, tumor characteristics, and comorbidity. The HR remained not significant in African-Americans compared to Caucasians after additionally adjusting for treatments (0.93, 0.82-1.06) or SES (0.94, 0.82-1.08) or both (0.88, 0.77-1.01). Women who underwent cancer-directed surgery and received adjuvant chemotherapy were 50% less likely to die than those who did not. The survival benefits from these therapies were similar in Caucasian and African-American women with ovarian cancer. There was no significant difference in survival between African-American and Caucasian women with ovarian cancer after adjusting for tumor characteristics, treatment, and sociodemographic factors. Although adjuvant chemotherapy was effective in prolonging survival, substantial numbers of women with ovarian cancer still did not receive chemotherapy.

Interferon-gamma in combination with carboplatin and paclitaxel as a safe and effective first-line treatment option for advanced ovarian cancer: results of a phase I/II study

We have previously shown that interferon-gamma 1b (IFN-gamma) in combination with cyclophosphamide and cisplatin significantly prolongs progression-free survival in ovarian cancer. In this phase I/II study, we examined if administration of IFN-gamma is also safe in combination with the current standard treatment, paclitaxel and carboplatin. Thirty-four patients with newly diagnosed advanced epithelial ovarian cancer, FIGO stage III/IV, were treated for six to nine cycles with paclitaxel (175 mg/m(2)) and carboplatin (area under the curve [AUC] 5) every 3 weeks. IFN-gamma was administered in an escalating dose from 6 days/cycle with 0.025 mg sc up to 9 days/cycle with 0.1 mg sc. As expected, administration of IFN-gamma was associated with flu-like symptoms. Grade 3/4 neutropenia was observed in 74% (25 out of 34) of patients. Other side effects, in particular peripheral neuropathies, were within the previously observed ranges for the paclitaxel plus carboplatin combination. Overall response rate (complete or partial response) in patients who received either six or nine doses (0.1 mg) of IFN-gamma/cycle (n = 28) was 71%. IFN-gamma is safe in combination with carboplatin and paclitaxel for first-line treatment of patients with advanced ovarian cancer. This combination should be further evaluated as an immunotherapeutic treatment option for ovarian cancer.

Optimizing gemcitabine regimens in ovarian cancer

Ovarian cancer represents the leading cause of death from gynecologic neoplasms. The chance of response to secondary treatment is currently disappointing; few agents have shown notable activity in recurrent/progressive patients. Among these agents, gemcitabine represents one of the most interesting newer antineoplastic agents, showing significant activity, synergism with cisplatin, and a mild toxicity profile in both platinum-sensitive and platinum-resistant (and also taxane-pretreated) recurrent/progressive patients. Moreover, first-line combination chemotherapy including gemcitabine has shown promising response rates in phase I and II studies. The ongoing phase III, five-arm, randomized Gynecologic Oncology Group Protocol 182/International Collaborative Ovarian Neoplasm 5 study should clarify the clinical impact of the addition of a third drug to the standard paclitaxel plus carboplatin treatment regimen.

Adeno-associated virus-mediated delivery of a mutant endostatin in combination with carboplatin treatment inhibits orthotopic growth of ovarian cancer and improves long-term survival

A human ovarian cancer cell line, which migrates to mouse ovaries and establishes peritoneal carcinomatosis, was used to evaluate the cooperative effect of an antiangiogenic gene therapy combined with chemotherapy. The ovarian carcinoma cell line MA148 was genetically modified by "Sleeping Beauty" transposon-mediated delivery of DsRed2 fluorescent protein. Stable, high-level expression of DsRed protein enabled in vivo imaging of peritoneal dissemination of ovarian cancer. Both external and internal imaging, along with histopathology, showed migration of i.p. injected human ovarian cancer cell line to mouse ovaries. Using this model, we evaluated the effect of adeno-associated virus (AAV)-mediated expression of a mutant endostatin either alone or in combination with carboplatin treatment. A single i.m. injection of recombinant AAV (rAAV)-mutant human endostatin with P125A substitution (P125A-endostatin) showed sustained expression of mutant endostatin. Antiangiogenic gene therapy inhibited orthotopic growth of ovarian cancer and resulted in 33% long-term tumor-free survival. A single cycle of carboplatin treatment combined with mutant endostatin gene therapy resulted in 60% of the animals remaining tumor free for >200 days, which was significantly better than rAAV-LacZ and/or carboplatin. Combination treatment delayed tumor appearance in 40% of the animals, wherein the residual tumors were smaller in size with limited or no peritoneal metastasis. These studies suggest that AAV-mediated gene therapy of P125A-endostatin in combination with carboplatin is a useful method to inhibit peritoneal dissemination of ovarian carcinoma.

Novel therapeutic agents in ovarian cancer

AIMS

Epithelial ovarian cancer is responsible for 4% of all cancer deaths in women, and the five-year overall survival of patients with advanced disease is 30-40%. Treatment currently comprises a combination of surgery and chemotherapy with carboplatin and paclitaxel. The main reason for treatment failure is that the majority of patients present with advanced disease, and current drugs are unable to effect a cure even in chemosensitive patients. This article systematically reviews novel therapeutic strategies that have been evaluated in patients with ovarian cancer in the last 5 years.

METHODS

Pubmed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed) and American Society of Clinical Oncology Annual conference abstracts were searched using the terms "(phase I OR phase II OR phase III OR phase 1 OR phase 2 OR phase 3) AND (ovary OR ovarian) AND (cancer OR carcinoma)" from January 2000 to May 2005 to identify studies for potential inclusion in this review. Reviews of novel therapies in ovarian cancer were also used to identify additional clinical trials.

FINDINGS

A wide range of therapeutic strategies are currently being evaluated in ovarian cancer. These include novel cytotoxics, small molecule inhibitors, monoclonal antibodies, gene therapy and immuno-therapy strategies. The rationale for the development of these agents includes enhancement of efficacy by targeting novel biological pathways, re-sensitisation to existing drugs, simplification of drug administration and/or reduction of drug-toxicity.

CONCLUSIONS

Current developments have the potential to result in substantial improvements in the outlook for women with ovarian cancer.

Ku protein targeting by Ku70 small interfering RNA enhances human cancer cell response to topoisomerase II inhibitor and gamma radiation

Ku protein is a heterodimer (Ku70 and Ku86) known to play an important role in V(D)J recombination, apoptosis, telomere fusion, and double-strand break repair. Its role in double-strand breaks is relevant to cancer therapy because lack of Ku86 causes one of the most radiation-responsive phenotypes (hamster cells, XRS5). Although it is known that the heterodimer is necessary for the various functions of this protein, the impact of targeting Ku in human cancer cells has not been shown due to lack of appropriate approaches. It is also not known whether complete knock-out of Ku protein is required to enhance the sensitivity of human cells to gamma radiation as Ku protein is much more abundant in human cells than in hamster cells. In the current article, we have investigated the direct effect of Ku70 depletion in human cervical epithelioid (HeLa) and colon carcinoma (HCT116) cells. We specifically targeted Ku70 mRNA by use of small interfering RNA (siRNA). Of the five Ku70 siRNA synthesized, three inhibited the expression of Ku70 by up to 70% in HeLa cells. We have tested the effect of chemically synthesized siRNAs for target sequence 5 (CS #5) on the response of HeLa cells 72 hours after transfection to gamma radiation and etoposide, as this showed the maximum inhibition of Ku70 expression. Ku70 siRNA induced a decrease in the surviving fraction of irradiated HeLa cells by severalfold. Similar sensitizing effects were observed for etoposide, a topoisomerase II inhibitor. Studies with HCT116 cells using the same Ku70 siRNA (CS #5) showed a direct correlation between expression of Ku70 and sensitization to radiation and etoposide treatments.

A HPLC validated assay of paclitaxel’s related impurities in pharmaceutical forms containing Cremophor® EL

A HPLC method has been developed for the determination of the paclitaxel's related impurities in pharmaceutical forms. This method ensures the rapid determination of related impurities in the presence of polyoxyl castor oil--the main constituent of paclitaxel's clinical formulation vehicle. The method is simple and does not require any preliminary treatment of the sample. The method was fully validated.

Carboplatin selectively induces the VEGF stress response in endothelial cells: Potentiation of antitumor activity by combination treatment with antibody to VEGF

Vascular Endothelial Growth Factor (VEGF) functions as a key regulator in tumor angiogenesis. In addition, VEGF is an important survival factor for endothelial cells under chemical or physical stress. In our report, we show that treatment of endothelial cells with the chemotherapeutic agent carboplatin significantly increased the expression of VEGF. Furthermore, neutralization of secreted VEGF with specific polyclonal anti-VEGF antibodies or monoclonal antibody sensitized endothelial cells to carboplatin treatment and increased apoptosis several-fold. Interestingly, carboplatin treatment did not alter VEGF expression in tumor cells. Similarly, antibody to VEGF did not change the chemosensitivity of tumor cells to this drug. Most importantly, tumor-bearing animals treated with carboplatin showed an increase in VEGF immunoreactivity in the tumor vasculature, confirming the in vitro studies. Based on these observations, we determined whether neutralization of VEGF could enhance the anti-tumor activity of carboplatin in an in vivo ovarian cancer model system. A combination therapy consisting of a suboptimal dose of carboplatin (32.5 mg/kg/inj., q3d x 5; i.p.) and polyclonal anti-VEGF antibody (2 mg/inj., q3d x 10; i.p.) significantly enhanced solid tumor growth inhibition over individual monotherapies and included multiple complete responses. These findings suggest that VEGF is a critical endothelial cell specific survival factor that is induced by carboplatin and contributes to the protection of tumor vasculature during chemotherapy treatment. In addition, these results provide evidence for a potential mechanism that underlies enhanced anti-tumor activity achieved with chemotherapy and anti-VEGF antibody combination treatment regimens as recently reported in a number of clinical trials. We conclude that a similar type of combination therapy may be applicable to many types of malignancies since VEGF expression was differentially induced in the tumor host environment (i.e., tumor vasculature) and not in the tumor cells themselves; hence, this phenomenon may be independent of the type and origin of the primary cancer.

Ovarian cancer: strategies for overcoming resistance to chemotherapy

Ovarian cancer is responsible for 4% of deaths from cancer in women. Treatment comprises a combination of surgery and chemotherapy, but patients typically experience disease relapse within 2 years of the initial treatment. Further treatment can extend survival, although relapse eventually occurs again. A better understanding of the mechanisms that underlie this drug resistance should allow treatment to be optimized, so that substantial improvements in the outlook for women with this disease can be achieved.

Ovarian cancer: progress and continuing controversies in management

Ovarian cancer is the most lethal of the gynaecological cancers, affecting approximately 1 in 75 women in the developed world. In most cases (>75%), the disease is disseminated beyond the ovary at diagnosis. For patients with stage III-IV disease, many clinicians agree that standard treatment should comprise six cycles of paclitaxel-carboplatin. Randomised trials over the past 10 years have indicated the superiority of paclitaxel-based treatment and that carboplatin is equivalent to cisplatin, but better tolerated. A recent trial has suggested that docetaxel may be a better option than paclitaxel, with reduced neurotoxicity and comparable efficacy. Overall treatment results remain unsatisfactory, since the median survival for these patients is 2-3 years. Future progress may be made by addressing the following issues: Would sequential regimes be more effective? Intriguing results from two large randomised trials (ICON-3 and GOG-132) indicate that single agent platinum might well be incorporated into such regimes. Additionally, a range of other agents could be tested as part of first-line regimes, having demonstrated activity in relapsed patients; these include topotecan, gemcitabine and liposomal doxorubicin. Newer agents, such as cell signalling inhibitors have shown potential as single agents, but may be particularly effective in combination with current drugs. Real progress can be expected when a better understanding is achieved of the mechanisms underlying clinical drug resistance in ovarian cancer, and a close laboratory-clinical interaction is crucial.