Expression of hypoxia-inducible factor 1alpha gene affects the outcome in patients with ovarian cancer

Integrated analysis of single-cell and bulk transcriptome reveals hypoxia-induced immunosuppressive microenvironment to predict immunotherapy response in high-grade serous ovarian cancer

Background

Hypoxia is significantly associated with cancer progression and treatment outcomes. Nevertheless, the precise molecular mechanisms underlying the hypoxia-induced immunosuppressive microenvironment in high-grade serous ovarian cancer (HGSOC) are still not fully understood.

Methods

By analyzing five independent transcriptomic datasets, we investigated the effect of hypoxia on prognosis and tumor microenvironment (TME) in HGSOC. The hypoxia levels and the intercellular communication signaling pathways were studied by using single-cell analysis. Furthermore, the Hypoxia-TME classifier was developed and then validated in the multiple HGSOC datasets. In addition, we also investigated the prognostic significance, genetic variations, signaling pathways, and the potential for immunotherapy benefits in different Hypoxia-TME subgroups.

Results

Hypoxia was identified as a crucial risk factor in HGSOC, and strongly correlated with an immunosuppressive microenvironment characterized by alterations in the composition and distribution of immune cells. Single-cell analysis elucidated the heterogeneity inherent within the TME in HGSOC, and demonstrated an association between the hypoxic TME and fibroblasts as well as macrophages. CellChat analysis identified SPP1-CD44 and CXCL12-CXCR4 as the principal signaling axes through which macrophages and fibroblasts interact with T cells, respectively. Moreover, a personalized Hypoxia-TME classifier was constructed and validated through the integration of the hypoxia (18 genes) and TME (7 immune cells) scores. It was observed that patients in the Hypoxialow/TMEhigh subgroup displayed a significantly better prognosis than other subgroups. Different subgroups exhibited unique genomic alterations and variations in signaling pathway differences, including TGF-β and Wnt/β-catenin pathways, which are closely associated with various biological functions. Finally, our results indicated that patients in the Hypoxialow/TMEhigh subgroup exhibit a better response to immunotherapy, suggesting the potential utility of the Hypoxia-TME classifier as a new biomarker in HGSOC.

Conclusion

Our study revealed hypoxia-induced immunosuppressive microenvironment, and developed Hypoxia-TME classifier to distinguish the prognosis, immune characteristics, and potential benefits of immunotherapy in HGSOC.

Hypoxia, but Not Normoxia, Reduces Effects of Resveratrol on Cisplatin Treatment in A2780 Ovarian Cancer Cells: A Challenge for Resveratrol Use in Anticancer Adjuvant Cisplatin Therapy

Natural compounds, such as resveratrol (Res), are currently used as adjuvants for anticancer therapies. To evaluate the effectiveness of Res for the treatment of ovarian cancer (OC), we screened the response of various OC cell lines to the combined treatment with cisplatin (CisPt) and Res. We identified A2780 cells as the most synergistically responding, thus optimal for further analysis. Because hypoxia is the hallmark of the solid tumor microenvironment, we compared the effects of Res alone and in combination with CisPt in hypoxia (pO2 = 1%) vs. normoxia (pO2 = 19%). Hypoxia caused an increase (43.2 vs. 5.0%) in apoptosis and necrosis (14.2 vs. 2.5%), reactive oxygen species production, pro-angiogenic HIF-1α (hypoxia-inducible factor-1α) and VEGF (vascular endothelial growth factor), cell migration, and downregulated the expression of ZO1 (zonula occludens-1) protein in comparison to normoxia. Res was not cytotoxic under hypoxia in contrast to normoxia. In normoxia, Res alone or CisPt+Res caused apoptosis via caspase-3 cleavage and BAX, while in hypoxia, it reduced the accumulation of A2780 cells in the G2/M phase. CisPt+Res increased levels of vimentin under normoxia and upregulated SNAI1 expression under hypoxia. Thus, various effects of Res or CisPt+Res on A2780 cells observed in normoxia are eliminated or diminished in hypoxia. These findings indicate the limitations in using Res as an adjuvant with CisPt therapy in OC.

Effects of the exercise-inducible myokine irisin on proliferation and malignant properties of ovarian cancer cells through the HIF-1 α signaling pathway

Exercise has been shown to be associated with reduced risk and improving outcomes of several types of cancers. Irisin -a novel exercise-related myokine- has been proposed to exert beneficial effects in metabolic disorders including cancer. No previous studies have investigated whether irisin may regulate malignant characteristics of ovarian cancer cell lines. In the present study, we aimed to explore the effect of irisin on viability and proliferation of ovarian cancer cells which was examined by MTT assay. Then, we evaluated the migratory and invasive abilities of the cells via transwell assays. Moreover, the percentage of apoptosis induction was determined by flow cytometry. Furthermore, the mRNA expression level of genes related to the aerobic respiration (HIF-1α, c-Myc, LDHA, PDK1 and VEGF) was detected by real-time PCR. Our data revealed that irisin treatment significantly attenuated the proliferation, migration and invasion of ovarian cancer cells. Additionally, irisin induced apoptosis in ovarian cancer cells. We also observed that irisin regulated the expression of genes involved in aerobic respiration of ovarian cancer cells. Our results indicated that irisin may play a crucial role in inhibition of cell growth and malignant characteristics of ovarian cancer. These findings may open up avenues for future studies to identify the further therapeutic use of irisin in ovarian cancer management.

Differential expression of hypoxia-inducible factors related to the invasiveness of epithelial ovarian cancer

Ovarian cancer is the most lethal gynecological cancer, and it is frequently diagnosed at advanced stages, with recurrences after treatments. Treatment failure and resistance are due to hypoxia-inducible factors (HIFs) activated by cancer cells adapt to hypoxia. IGFBP3, which was previously identified as a growth/invasion/metastasis suppressor of ovarian cancer, plays a key role in inhibiting tumor angiogenesis. Although IGFBP3 can effectively downregulate tumor proliferation and vasculogenesis, its effects are only transient. Tumors enter a hypoxic state when they grow large and without blood vessels; then, the tumor cells activate HIFs to regulate cell metabolism, proliferation, and induce vasculogenesis to adapt to hypoxic stress. After IGFBP3 was transiently expressed in highly invasive ovarian cancer cell line and heterotransplant on mice, the xenograft tumors demonstrated a transient growth arrest with de-vascularization, causing tumor cell hypoxia. Tumor re-proliferation was associated with early HIF-1α and later HIF-2α activations. Both HIF-1α and HIF-2α were related to IGFBP3 expressions. In the down-expression of IGFBP3 in xenograft tumors and transfectants, HIF-2α was the major activated protein. This study suggests that HIF-2α presentation is crucial in the switching of epithelial ovarian cancer from dormancy to proliferation states. In highly invasive cells, the cancer hallmarks associated with aggressiveness could be activated to escape from the growth restriction state.

Propofol-Based Total Intravenous Anesthesia is Associated with Better Survival than Desflurane Anesthesia in Epithelial Ovarian Cancer Surgery: A Retrospective Cohort Study

Background: Previous studies have shown that anesthetic techniques can affect outcomes of cancer surgery. We investigated the association between anesthetic techniques and patient outcomes after elective epithelial ovarian cancer surgery.

Methods: This was a retrospective cohort study of patients who received elective open surgery for epithelial ovarian cancer between January 2009 and December 2014. Patients were grouped according to the administration of propofol or desflurane anesthesia. Kaplan–Meier analysis was performed, and survival curves were constructed from the date of surgery to death. Univariate and multivariate Cox regression models were used to compare hazard ratios for death after propensity matching. Subgroup analyses were performed for age, body mass index, preoperative carbohydrate antigen-125 level, International Federation of Gynecology and Obstetrics staging, and operation and anesthesia time.

Results: In total, 165 patients (76 deaths, 46.1%) who received desflurane anesthesia and 119 (30 deaths, 25.2%) who received propofol anesthesia were eligible for analysis. After propensity matching, 104 patients were included in each group. In the matched analysis, patients who received propofol anesthesia had better survival with a hazard ratio of 0.52 (95% confidence interval, 0.33–0.81; p = 0.005). Subgroup analyses also showed significantly better survival with old age, high body mass index, elevated carbohydrate antigen-125 level, advanced International Federation of Gynecology and Obstetrics stage, and prolonged operation and anesthesia time in the matched propofol group. In addition, patients administered with propofol anesthesia had less postoperative recurrence and metastasis than those administered with desflurane anesthesia in the matched analysis.

Conclusion: Propofol anesthesia was associated with better survival in patients who underwent elective epithelial ovarian cancer open surgery. Prospective studies are warranted to evaluate the effects of propofol anesthesia on oncological outcomes in patients with epithelial ovarian cancer.

The prognostic significance of high/positive expression of tissue VEGF in ovarian cancer

Background & aim

At present, numerous reports have shown that high/positive expression of tissue vascular endothelial growth factor (VEGF) may be associated with the prognosis of patients with ovarian cancer. However, their results still remained controversy. Thus, this meta-analysis was designed to analyze and assess the prognostic value of tissue VEGF expression in patients with ovarian cancer.

Method

We searched PubMed, Embase, Cochrane Library and Web of Science to October, 2017. Hazard Ratio (HR) with its 95% confidence intervals (CIs) was used to evaluate the association between high/positive expression of tissue VEGF and the prognosis of ovarian cancer patients. All statistical analyses were performed using standard statistical procedures provided in RevMan 5.2.

Result

A total of 18 studies (including 1145 patients) were included for this meta-analysis. The positive/high expression of tissue VEGF had an obvious association with overall survival (OS) (HR 2.24, 95% CI 1.36–3.70; P=0.002), progression-free survival (PFS) (HR 1.60, 95% CI 1.11–2.31; P=0.01) and disease-free survival (DFS) (HR 3.49, 95% CI 1.27–9.56; P=0.02) of patients with ovarian cancer respectively.

Conclusion

The present meta-analysis indicated that positive/high expression of tissue VEGF may have a close association with survival of ovarian cancer.

Serum Vascular Endothelial Growth Factor-A as a Prognostic Biomarker for Epithelial Ovarian Cancer

Background

Bevacizumab, which targets vascular endothelial growth factor (VEGF)-A, has recently been proven to be effective for the treatment of epithelial ovarian cancer (EOC). Thus, interest in VEGF-A has increased. There are few reports on concomitant detection of both ligands and its soluble receptors in serum samples, and the significance of serum VEGF-A in EOC is unclear, unlike the situation with tissue samples. We conducted the present study to explore the levels of serum VEGF family and its receptors and to evaluate their utility as prognostic biomarkers.

Methods

A total of 128 patients with EOC, who were consecutively treated at Tottori University Hospital between 2006 and 2012, were included. Blood samples were collected before initial surgery. Serum concentrations of VEGF-A, VEGF-C, VEGFR-1, and VEGFR-2 were analyzed by enzyme-linked immunosorbent assay. We also examined the mRNA and protein expression of VEGF-A in tumor tissue from 30 cases by real-time reverse transcription polymerase chain reaction and immunohistochemistry.

Results

The levels of VEGF-A in patients with stage III/IV disease were significantly higher than those with stage I/II disease (P = 0.0036). On the other hand, the level of VEGFR-2 in stage III/IV was significantly lower than that in stage I/II (P = 0.0026). With the cutoff value of VEGF/VEGFRs at the median level, the overall survival (OS) for patients with high VEGF-A levels was significantly lower than those with low levels (P = 0.015). Patients with high VEGFR-2 levels showed better prognosis than those with low VEGFR-2 levels (P = 0.023). Multivariate analysis revealed that International Federation of Gynecology and Obstetrics stage and serum VEGF-A were independent prognostic factors for OS [hazard ratio 2.01, 95% confidence interval (1.13–3.63), P = 0.017]. There was no significant correlation between mRNA or protein expression and serum levels of VEGF-A.

Conclusions

Serum VEGF-A is an independent prognostic factor for OS in patients with EOC, implying that serum VEGF-A is a prognostic biomarker for EOC. Further study to validate the data is needed.

SNAIL gene inhibited by hypoxia-inducible factor 1α (HIF-1α) in epithelial ovarian cancer

The aim of this study was to investigate the relationship between HIF-1α and SNAIL gene expression in the epithelial ovarian cancer (EOC) cell line. EOC cells were treated with hypoxia, hypoxia combined with rapamycin, and control. The expression of HIF-1α and E-cad were assessed by reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. The gene expression of SNAIL was studied by RT-PCR and real-time PCR. RNA interference technology was used to determine the relationship between HIF-1α and SNAIL. The present study indicated that the HIF-1α protein was expressed and increased in EOC cell line. SNAIL mRNA was found to increase and E-cad expression decreased with the time of hypoxia prolonged. Hypoxia increased invasion abilities of EOC cell line, but compared with cells exposed to hypoxia, the change of invasive ability of cells with rapamycin had no effect. The expression of HIF-1α protein and SNAIL mRNA could be inhibited gradually by rapamycin. siRNA of HIF-1α could suppress the expression of SNAIL while siRNA of SNAIL had no influence on HIF-1α protein expression. HIF-1α may be the upstream of the SNAIL gene in EOC. Our data suggested that HIF-1α might be an upregulator of the SNAIL gene and HIF-1α-SNAIL-E-cad pathway may play an important role in EOC invasion and metastasis.

Clinicopathological characteristics of gynecological cancer associated with hypoxia-inducible factor 1α expression: a meta-analysis including 6,612 subjects

BACKGROUND

Gynecological cancer is characterized by tumor hypoxia. However, the role of hypoxia-inducible factor 1α (HIF-1α) in gynecological cancer remains unclear.

METHOD

Electronic databases including Cochrane Library, PUBMED, Web of Knowledge and clinical trial registries were searched from inception through October 2014 for published, case-control studies assessing the association between HIF-1α and the clinicopathological characteristics of gynecological cancer. We pooled results from 59 studies using fixed or random-effects models and present results as odds ratios (ORs) following the PRISMA guidelines.

RESULTS

Our meta-analysis, which included 6,612 women, demonstrated that the expression of HIF-1α was associated with the clinicopathological characteristics of gynecological cancer. The expression of HIF-1α in cancer or borderline tissue was significantly higher than that in normal tissue (cancer vs. normal: odds ratio (OR) =9.59, 95% confidence interval (CI): 5.97, 15.39, p<0.00001; borderline vs. normal: OR=4.13, 95% (CI): 2.43, 7.02, p<0.00001; cancer vs. borderline: OR=2.70, 95% (CI): 1.69, 4.31, p<0.0001). The expression of HIF-1α in III-IV stage or lymph node metastasis was significantly higher than that in I-II stage or that without lymph node metastasis, respectively (OR=2.66, 95% (CI): 1.87,3.79, p<0.00001; OR= 3.98, 95% (CI): 2.10,12.89, p<0.0001). HIF-1α was associated with histological grade of cancer (Grade 3 vs. Grade 1: OR=3.77, 95% (CI): 2.76,5.16, p<0.00001; Grade 3 vs. Grade 2: OR=1.62, 95% (CI): 1.20,2.19, p=0.002; Grade 2 vs. Grade 1: OR=2.34, 95% (CI): 1.82,3.00, p<0.00001),5-years disease free survival (DFS) rates (OR=2.93, 95% (CI):1.43,6.01, p=0.001) and 5-years overall survival (OS) rates (OR=5.53, 95% (CI): 2.48,12.31, p<0.0001).

CONCLUSION

HIF-1α is associated with the malignant degree, FIGO stage, histological grade, lymph node metastasis, 5-years survival rate and recurrence rate of gynecological cancer. It may play an important role in clinical treatment and prognostic evaluation.

Sulforaphane reduces molecular response to hypoxia in ovarian tumor cells independently of their resistance to chemotherapy

One of the recently emerging anticancer strategies is the use of natural dietary compounds, such as sulforaphane, a cancer-chemopreventive isothiocyanate found in broccoli. Based on the growing evidence, sulforaphane acts through molecular mechanisms that interfere with multiple oncogenic pathways in diverse tumor cell types. Herein, we investigated the anticancer effects of bioavailable concentrations of sulforaphane in ovarian carcinoma cell line A2780 and its two derivatives, adriamycin-resistant A2780/ADR and cisplatin-resistant A2780/CP cell lines. Since tumor microenvironment is characterized by reduced oxygenation that induces aggressive tumor phenotype (such as increased invasiveness and resistance to chemotherapy), we evaluated the effects of sulforaphane in ovarian cancer cells exposed to hypoxia (2% O₂). Using the cell-based reporter assay, we identified several oncogenic pathways modulated by sulforaphane in hypoxia by activating anticancer responses (p53, ARE, IRF-1, Pax-6 and XRE) and suppressing responses supporting tumor progression (AP-1 and HIF-1). We further showed that sulforaphane decreases the level of HIF-1α protein without affecting its transcription and stability. It can also diminish transcription and protein level of the HIF-1 target, CA IX, which protects tumor cells from hypoxia-induced pH imbalance and facilitates their migration/invasion. Accordingly, sulforaphane treatment leads to diminished pH regulation and reduced migration of ovarian carcinoma cells. These effects occur in all three ovarian cell lines suggesting that sulforaphane can overcome the chemoresistance of cancer cells. This offers a path potentially exploitable in sensitizing resistant cancer cells to therapy, and opens a window for the combined treatments of sulforaphane either with conventional chemotherapy, natural compounds, or with other small molecules.

Low-dose-intensity bevacizumab with weekly irinotecan for platinum- and taxanes-resistant epithelial ovarian cancer

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of low-dose-intensity bevacizumab and weekly irinotecan as salvage treatment for patients with platinum- and taxanes-resistant advanced epithelial ovarian cancer.

METHODS

Fifty-two patients with platinum- and taxanes-resistant advanced epithelial ovarian cancer received bevacizumab 5 mg/Kg days 1 and 15; irinotecan 60 mg/m(2) days 1, 8 and 15. The combined therapy was repeated every 28 days, up to six cycles.

RESULTS

A total of 230 cycles of bevacizumab combined with irinotecan were administrated to 52 patients. Among the 52 patients, 22 patients achieved partial response (42.3 %); 12 patients had stable disease (23.1 %) and 18 patients experienced disease progression (34.6 %). The median progression-free survival and the median overall survival were 8.0 months (95 % confidence interval: 6.74-9.26 months) and 13.8 months (95 % confidence interval: 11.97-15.63 months), respectively. The most frequent grade 3-4 hematologic toxicities were neutropenia (11.5 %) and thrombocytopenia (3.8 %). The non-hematologic toxicities included grade 3 diarrhea (3.8 %) and hypertension (3.8 %). Two patients (3.8 %) were confirmed with deep vein thrombosis. Febrile neutropenia, symptomatic cardiac dysfunction and gastrointestinal perforation were not observed in this study.

CONCLUSIONS

The combination of low-dose-intensity bevacizumab and weekly irinotecan was an effective and safe regimen for patients with platinum- and taxanes-resistant epithelial ovarian cancer.

Twist2 promotes ovarian cancer cell survival through activation of Akt

Hypoxia-inducible factor-1 α (HIF-1α) is an important prognostic factor in ovarian carcinoma. Hypoxia contributes to tumor progression and is involved in the epithelial-mesenchymal transition (EMT). Twist2 is an EMT regulator, however, it remains poorly understood in ovarian carcinoma. The present study evaluated the expression of HIF-1α and Twist2 and further investigated whether Twist2 is involved in hypoxia-induced apoptosis in ovarian cancer. A series of matched paraffin-embedded tissue sections from human primary ovarian cancer and normal ovarian tissues were examined through immunohistochemical analysis, a Twist2-overexpressing stable ovarian cancer cell line was established and deferoxamine (DFO) was introduced to simulate hypoxic conditions. DFO-induced apoptosis was examined by fluorescence microscopy, MTT assays and flow cytometry. In addition, a western blot analysis was performed to examine the molecular mechanism(s) of action. Twist2 increased in epithelial ovarian cancers associated with HIF-1α expression. The acquired expression of Twist2 was able to promote the survival of ovarian cancer cells through Akt phosphorylation under DFO-induced hypoxic stress. The results suggest that Twist2 activates the PI-3K-Akt pathway to protect cells from apoptosis in a hypoxic environment. Moreover, Twist2 may be involved in the HIF-1α signaling pathway in ovarian cancer.

The prognostic value of vascular endothelial growth factor in ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

The prognostic role of vascular endothelial growth factor (VEGF) in ovarian cancer remains inconclusive. This meta-analysis aimed to explore the association between VEGF overexpression and survival outcomes in ovarian cancer patients.

METHODS

Studies were identified from PubMed and EMBASE searches performed on January 2nd, 2011. After careful review, survival data were extracted from eligible studies. A meta-analysis was performed to generate combined hazard ratio (HR) for progression-free survival (PFS) and overall survival (OS) in serum and tumor tissue studies.

RESULTS

Sixteen studies with 1111 patients were analyzed. Elevated serum VEGF was significantly associated with poor PFS [HR 2.46, 95% CI (1.84, 3.29)] and OS [HR 2.21, 95% CI (1.57, 3.13)]. No significant heterogeneity existed in serum studies. Similarly, tissue VEGF overexpression was associated with poor PFS [HR 1.63, 95% CI (1.09, 2.42)] and OS [HR 1.70, 95% CI (1.01, 2.87)]. However, significant heterogeneity was found in tissue studies, with I(2) of 44% for PFS and 64% for OS. Studies were stratified into subgroups by International Federation of Gynecology and Obstetrics (FIGO) stages. Subgroup analyses showed that high tissue VEGF was significantly associated with shorter PFS [HR 5.34, 95% CI (1.95, 14.59)] and OS [HR 6.13, 95% CI (2.47, 15.26)] in studies where predominantly early-stage patients were included, but not in studies with a majority of advanced-stage patients. Subgroup analysis was not performed in serum studies because all those studies enrolled more patients in advanced stages than early stages.

CONCLUSIONS

Overexpression of VEGF in primary tumor and serum associates with poor PFS and OS for patients with ovarian cancer. The association between high tissue VEGF level and poor prognosis exists in early stage patients, but not in advanced stage patients.

Aberrant expression of the mammalian target of rapamycin, hypoxia-inducible factor-1α, and glucose transporter 1 in the development of ovarian clear-cell adenocarcinoma

Ovarian clear-cell adenocarcinoma (CCA) is known to be a type of cancer in humans with a high frequency of expression of the mammalian target of rapamycin (mTOR), hypoxia-inducible factor-1 (HIF-1), and glucose transporter 1 (Glut1). In this study, we aimed to determine how these alterations contribute to tumor development of CCAs. Immunohistochemical expressions of phosphorylated-mTOR (p-mTOR), HIF-1α, and Glut1 were analyzed in 36 CCAs and 60 coexistent putative precursor lesions: 19 nonatypical and 16 atypical endometriotic lesions, and 11 benign and 14 borderline clear-cell adenofibroma (CCAF) components. Twenty-one cases with solitary endometriosis were also examined. The frequencies of immunopositivity for p-mTOR (in cytoplasm or nucleus), HIF-1α (in nucleus), and Glut1 increased in accordance with higher cytological atypia in the putative precursors: 58%, 5%, and 16% in the nonatypical endometriosis; 63%, 37%, and 50% in the atypical endometriosis; 77%, 95%, and 95% in the endometriosis-associated CCAs; 27%, 0%, and 0% in the benign-CCAF components; 64%, 79%, and 43% in the borderline CCAF components; and 71%, 100%, and 93% in the CCAF-associated CCAs, respectively. p-mTOR, HIF-1α (in the nucleus), and Glut1 were positive in 10%, 5%, and 19% of the solitary endometriosis, respectively. In the putative precursor lesions coexisting with CCA, a strong correlation in the expression between p-mTOR and HIF-1α and between HIF-1α and Glut1 was identified. Expressions of p-mTOR, HIF-1α, and Glut1 have already been evident in the putative precursor lesions of CCA, and these alterations cumulatively occur in the development of ovarian CCA.

Over-expression of semaphorin4D, hypoxia-inducible factor-1α and vascular endothelial growth factor is related to poor prognosis in ovarian epithelial cancer

Semaphorin4D (SEMA4D) has been regarded as an important protein in tumor angiogenesis, though originally identified in neurodevelopment. SEMA4D is extensively expressed in several malignant solid tumors. Nevertheless, the function and expression of SEMA4D in epithelial ovarian cancer (EOC) is as yet not well understood. The aim of this study was to investigate SEMA4D expression in EOC and evaluate its clinical–pathological and prognostic significance. Immunohistochemistry was used to analyze SEMA4D expression and tumor angiogenesis-related proteins (HIF-1α and VEGF) in tissues from 40 patients with normal ovarian epithelia and 124 EOC patients. SEMA4D was found to be expressed in 61.3% of the 124 EOC tissues, which was significantly higher than in the normal ovarian epithelia (p < 0.001). SEMA4D expression correlated with HIF-1α and VEGF closely (ρ = 0.349 and 0.263, p < 0.001). Positive SEMA4D staining was significantly higher in tissues from patients with low histological grade, FIGO stage III-IV, lymph node metastasis and residual disease ≥1 cm (p < 0.05). In the Cox proportional hazard mode, SEMA4D expression and histologic grade were independent indicators of overall survival (OS) and progress-free survival (PFS) for EOC patients. These findings suggest that the cooperation of SEMA4D, HIF-1α, and VEGF may indicate poor prognosis for patients with EOC, thereby demonstrating that SEMA4D and its role in angiogenesis in EOC warrants further study.

Clinical trials and future potential of targeted therapy for ovarian cancer

Ovarian cancer is the leading cause of death in women with gynecological cancer. Most patients are diagnosed at an advanced stage with a poor prognosis. Currently, surgical tumor debulking followed by chemotherapy based on platinum and taxane is the standard treatment for advanced disease. However, these patients remain at great risk for recurrence and developing drug resistance. Therefore, new treatment strategies are needed to improve outcomes for patients with advanced and recurrent ovarian cancer. Several agents targeted at particular molecules have been developed for ovarian cancer and are now entering clinical trials. The functional targets of these agents are aberrations in tumor tissues including angiogenesis, the human epidermal growth factor receptor family, poly(ADP-ribose) polymerase (PARP), mammalian target of rapamycin (mTOR) signaling pathway, and α-folate receptor (α-FR). The anti-angiogenic compound bevacizumab has been reported as the most effective targeted agent. Bevacizumab plus chemotherapy prolonged progression-free survival (PFS) both for advanced and platinum-sensitive recurrent ovarian cancer, but did not increase overall survival. A PARP inhibitor, olaparib, applied as maintenance treatment also improved PFS in platinum-sensitive relapsed ovarian cancer. Furthermore, mTOR inhibitors and a monoclonal antibody to α-FR, farletuzumab, are attractive treatment strategies either alone or combined with chemotherapy. Understanding the tumor molecular biology and identifying predictive biomarkers are essential steps in selecting the best treatment strategies. This article reviews available clinical data on the most promising targeted agents for ovarian cancer.

A case series of low dose bevacizumab and chemotherapy in heavily pretreated patients with epithelial ovarian cancer

BACKGROUND

The addition of bevacizumab to standard chemotherapy prolongs progression free survival in the first line treatment of epithelial ovarian cancer (EOC), but its cost/effectiveness is debated. We assessed the safety and activity of a lower dose of bevacizumab in pretreated advanced stage EOC.

METHODS

We treated 15 patients, mostly with platinum resistant EOC, who had received a median of four prior cytotoxic regimens, with bevacizumab 5-7.5 mg/kg q21 days in combination with either carboplatin (n = 8), oral cyclofosfamide (n = 5) or weekly paclitaxel (n = 2). Bevacizumab was administered until disease progression. Tumor response was assessed by CA125 and fusion 18 F-FDG PET/contrast enhanced CT.

RESULTS

The median number of bevacizumab cycles was 21 (range 3-59). The median baseline CA125 was 272 U/ml and decreased to 15.2 U/ml at nadir. Tumor response was 4 complete response (CR) (26.7%) and 7 partial response (PR) (46.7%) by chemotherapy (CT), with an overall response rate of 73.4% (95% CI, 51.0 - 95.8) according to Response Evaluation Criteria In Solid Tumors (RECIST), and 6 CR (40%) and 4 PR (26.7%) by PET, for an overall metabolic response rate of 67% (95%CI, 42.8 - 90.6) according to PET Response Criteria in Solid Tumors (PERCIST). Median progression free survival (PFS) was 21 months and median overall survival (OS) was 24 months. Grade 3 adverse events related to bevacizumab were hypertension (n = 2), proteinuria (n = 1) and epistaxis (n = 5). Treatment was delayed in five patients for nasal bleeding or uncontrolled hypertension.

CONCLUSIONS

Low-dose bevacizumab and chemotherapy was well tolerated and active in a heavily pretreated population of advanced EOC. Further studies should assess the activity of low dose bevacizumab in EOC.

Special Agents Hunting Down Women Silent Killer: The Emerging Role of the p38α Kinase

Ovarian cancer is sensitive to chemotherapy with platinum compounds; however, the therapy success rate is significantly lowered by a high incidence of recurrence and by the acquisition of drug resistance. These negative outcomes mainly depend on altered apoptotic and drug resistance pathways, determining the need for the design of new therapeutic strategies to improve patient survival. This challenge has become even more critical because it has been recognized that hindering uncontrolled cell growth is not sufficient as the only curative approach. In fact, while current therapies are mostly conceived to impair survival of highly proliferating cells, several lines of research are now focusing on cancer-specific features to specifically target malignant cells with the aim of avoiding drug resistance and reducing adverse effects. Recently, great interest has been generated by the identification of metabolic reprogramming mechanisms occurring in cancer cells, such as the increase in glycolysis levels. In this light, pharmacologic manipulation of relevant pathways involved in cancer-specific metabolism and drug resistance could prove an effective approach to treat ovarian cancer patients.

Bevacizumab and ovarian cancer

PURPOSE OF REVIEW

Vascular endothelial growth factor (VEGF), one of the major pathways involved in tumor angiogenesis, is often overexpressed in epithelial ovarian cancer (EOC), and therefore an attractive target for therapy. This review aims to evaluate the rationale for targeting angiogenic pathways by the usage of the anti-VEGF agent bevacizumab in EOC.

RECENT FINDINGS

Bevacizumab monotherapy has been shown to be effective in the treatment of EOC with response rate of 16-21% in phase II trials. In phase III trials, patients with advanced EOC who received combination chemotherapy (paclitaxel + carboplatin) plus bevacizumab with maintenance bevacizumab had significantly longer progression-free survival than those who received chemotherapy alone, but did not prolong overall survival. The most common grade 3/4 adverse events of bevacizumab monotherapy include hypertension and proteinuria, while heavily pretreated patients were at increased risk of bowel perforation. The addition of bevacizumab to the standard chemotherapy in patients with advanced EOC may not be cost-effective.

SUMMARY

Bevacizumab has significant activity and is the most promising drug in EOC. However, understanding of its unique adverse events and identification of predictive biomarkers of bevacizumab response are necessary in order to select patients most likely to benefit from this therapy.

Intraoperative imaging in ovarian cancer: fact or fiction?

Tumor-targeted fluorescence imaging for cancer diagnosis and treatment is an evolving field of research that is on the verge of clinical implementation. As each tumor has its unique biologic profile, selection of the most promising targets is essential. In this review, we focus on target finding in ovarian cancer, a disease in which fluorescence imaging may be of value in both adequate staging and in improving cytoreductive efforts, and as such may have a beneficial effect on prognosis. Thus far, tumor-targeted imaging for ovarian cancer has been applied only in animal models. For clinical implementation, the five most prominent targets were identified: folate receptor α, vascular endothelial growth factor, epidermal growth factor receptor, chemokine receptor 4, and matrix metalloproteinase. These targets were selected based on expression rates in ovarian cancer, availability of an antibody or substrate aimed at the target approved by the Food and Drug Administration, and the likelihood of translation to human use. The purpose of this review is to present requirements for intraoperative imaging and to discuss possible tumor-specific targets for ovarian cancer, prioritizing for targets with substrates ready for introduction into the clinic.

Tumour hypoxia promotes tolerance and angiogenesis via CCL28 and T(reg) cells

Although immune mechanisms can suppress tumour growth, tumours establish potent, overlapping mechanisms that mediate immune evasion. Emerging evidence suggests a link between angiogenesis and the tolerance of tumours to immune mechanisms. Hypoxia, a condition that is known to drive angiogenesis in tumours, results in the release of damage-associated pattern molecules, which can trigger the rejection of tumours by the immune system. Thus, the counter-activation of tolerance mechanisms at the site of tumour hypoxia would be a crucial condition for maintaining the immunological escape of tumours. However, a direct link between tumour hypoxia and tolerance through the recruitment of regulatory cells has not been established. We proposed that tumour hypoxia induces the expression of chemotactic factors that promote tolerance. Here we show that tumour hypoxia promotes the recruitment of regulatory T (T(reg)) cells through induction of expression of the chemokine CC-chemokine ligand 28 (CCL28), which, in turn, promotes tumour tolerance and angiogenesis. Thus, peripheral immune tolerance and angiogenesis programs are closely connected and cooperate to sustain tumour growth.

Tumour hypoxia promotes tolerance and angiogenesis via CCL28 and T(reg) cells

Although immune mechanisms can suppress tumour growth, tumours establish potent, overlapping mechanisms that mediate immune evasion. Emerging evidence suggests a link between angiogenesis and the tolerance of tumours to immune mechanisms. Hypoxia, a condition that is known to drive angiogenesis in tumours, results in the release of damage-associated pattern molecules, which can trigger the rejection of tumours by the immune system. Thus, the counter-activation of tolerance mechanisms at the site of tumour hypoxia would be a crucial condition for maintaining the immunological escape of tumours. However, a direct link between tumour hypoxia and tolerance through the recruitment of regulatory cells has not been established. We proposed that tumour hypoxia induces the expression of chemotactic factors that promote tolerance. Here we show that tumour hypoxia promotes the recruitment of regulatory T (T(reg)) cells through induction of expression of the chemokine CC-chemokine ligand 28 (CCL28), which, in turn, promotes tumour tolerance and angiogenesis. Thus, peripheral immune tolerance and angiogenesis programs are closely connected and cooperate to sustain tumour growth.

The expression of HIF-1α in primary hepatocellular carcinoma and its correlation with radiotherapy response and clinical outcome

The purpose of this study was to evaluate the relationship between hypoxia-inducible factor-1α (HIF-1α) protein expression in hepatocellular carcinoma (HCC), and responses of abdominal metastatic lymph nodes (LNs) from HCC patients treated with external beam radiotherapy (EBRT). HIF-1α immunohistochemical staining was performed on tissue microarrays (TMAs) of primary HCC specimens from 69 HCC patients with abdominal LN metastases. All patients received abdominal metastatic LN EBRT at the Department of Radiation Oncology at Zhongshan Hospital. A receiver-operating characteristic (ROC)-based approach and logistical regression analysis were used to determine the predictive value of HIF-1α expression in primary tumors with HCC metastatic LN EBRT response. Kaplan-Meier curves and log-rank tests were used to analyze patient survival. Cox proportional hazards regression model was used to analyze independent prognostic factors. HIF-1α expression was correlated with blood hemoglobin (Hb: r = -0.280, P = 0.020), response of abdominal metastatic LNs to EBRT (r = 0.286, P = 0.017), locoregional recurrence (r = 0.278, P = 0.021), and cancer-specific deaths (r = 0.298, P = 0.013). HIF-1α expression was predictive of EBRT response of metastatic LNs [area under the curve (AUC): 0.646; 95% confidence interval (CI): 0.499-0.793; P = 0.047], locoregional recurrence (AUC: 0.657; 95% CI: 0.509-0.805; P = 0.049) and cancer-specific deaths (AUC: 0.671; 95% CI: 0.531-0.812; P = 0.035). Patients with tumors exhibiting high HIF-1α expression had significantly poorer overall survival (OS) than those with low tumor expression of HIF-1α (P = 0.016). Multivariate analysis showed that Hb (P = 0.035), vascular invasion (P = 0.026), Child-Pugh score (P < 0.001), intrahepatic tumor control (P < 0.001), and HIF-1α (P = 0.020) were independent prognosis factors for OS of HCC patients after receiving abdominal metastatic LN EBRT. HIF-1α expression in primary HCCs was associated with EBRT response of abdominal metastatic LNs and poor prognosis.

Targeted therapies in epithelial ovarian cancer: Molecular mechanisms of action

Ovarian cancer is the leading cause of death in women with gynecological cancer. Most patients are diagnosed at an advanced stage and have a poor prognosis. Currently, surgical tumor debulking, followed by platinum- and taxane-based chemotherapy is the standard treatment for advanced ovarian cancer. However, these patients are at great risk of recurrence and emerging drug resistance. Therefore, novel treatment strategies are required to improve outcomes for women with advanced ovarian cancer. A variety of molecular targeted agents, the majority of which are monoclonal antibodies and small-molecule protein-kinase inhibitors, have been explored in the management of ovarian cancer. The targets of these agents include angiogenesis, the human epidermal growth factor receptor family, ubiquitin-proteasome pathway, epigenetic modulators, poly(ADP-ribose) polymerase (PARP), and mammalian target of rapamycin (mTOR) signaling pathway, which are aberrant in tumor tissue. The antiangiogenic agent, bevacizumab, has been reported as the most effective targeted agent and should be included in the standard chemotherapeutic regimen for advanced ovarian cancer. PARP inhibitors, which are mainly used in breast and ovarian cancer susceptibility gene-mutated patients, and mTOR inhibitors are also attractive treatment strategies, either alone or combination with chemotherapy, for ovarian cancer. Understanding the tumor molecular biology and identification of predictive biomarkers are essential steps for selection of the best treatment strategies. This article reviews the molecular mechanisms of the most promising targeted agents that are under early phase clinical evaluation for ovarian cancer.

Predictive and prognostic protein biomarkers in epithelial ovarian cancer: recommendation for future studies

Epithelial ovarian cancer is the most lethal gynecological malignancy. Due to its lack of symptoms, this disease is diagnosed at an advanced stage when the cancer has already spread to secondary sites. While initial rates of response to first treatment is >80%, the overall survival rate of patients is extremely low, mainly due to development of drug resistance. To date, there are no reliable clinical factors that can properly stratify patients for suitable chemotherapy strategies. Clinical parameters such as disease stage, tumor grade and residual disease, although helpful in the management of patients after their initial surgery to establish the first line of treatment, are not efficient enough. Accordingly, reliable markers that are independent and complementary to clinical parameters are needed for a better management of these patients. For several years, efforts to identify prognostic factors have focused on molecular markers, with a large number having been investigated. This review aims to present a summary of the recent advances in the identification of molecular biomarkers in ovarian cancer patient tissues, as well as an overview of the need and importance of molecular markers for personalized medicine in ovarian cancer.

p38alpha is required for ovarian cancer cell metabolism and survival

INTRODUCTION

Ovarian cancer is highly sensitive to chemotherapy but also shows a high rate of recurrence and drug resistance. These negative outcomes mostly depend on altered apoptotic pathways, making the design of new therapeutic strategies based on the induction of other types of cell death highly desirable. Several lines of research are now addressing cancer-specific features to specifically target tumor cells, thus reducing adverse effects. In this light, a great deal of attention has been devoted to the metabolic reprogramming occurring in cancer cells, which display increased levels of glycolysis compared with their normal counterparts. We recently showed that inhibition of p38alpha impairs key metabolic functions of colorectal cancer cells, inducing growth arrest, autophagy, and cell death both in vivo and in vitro. These effects are mediated by a switch from hypoxia-inducible factor 1alpha (HIF1alpha) to forkhead transcription factor O (FoxO)-dependent transcription.

METHODS

We first characterized p38 expression in OVCAR-3, A2780, and SKOV-3 ovarian cancer cell lines. Then, we treated these cells with the p38alpha/p38beta-specific inhibitor SB202190 and performed a morphological, proliferation, and survival analyses. Finally, we studied HIF1alpha and FoxO3A expressions and signaling pathways to evaluate their role in SB202190-induced effects.

RESULTS

p38alpha blockade induces the formation of intracellular autophagic vacuoles and reduces growth and viability of ovarian cancer cells. As in colorectal cancer, the underlying molecular mechanism seems to rely on a shift from HIF1alpha- to FoxO3A-dependent transcription, which is promoted by the activation of the adenosine monophosphate-activated protein kinase pathway.

CONCLUSIONS

These data corroborate the hypothesis that pharmacological modulation of genes involved in cancer-specific homeostasis, such as p38alpha, might be exploited to design new therapeutic approaches to cancer treatment.

Hypoxia promotes expansion of the CD133-positive glioma stem cells through activation of HIF-1alpha

Hypoxia contributes to the progression of a variety of cancers by activating adaptive transcriptional programs that promote cell survival, motility and tumor angiogenesis. Although the importance of hypoxia and subsequent hypoxia-inducible factor-1alpha (HIF-1alpha) activation in tumor angiogenesis is well known, their role in the regulation of glioma-derived stem cells is unclear. In this study, we show that hypoxia (1% oxygen) promotes the self-renewal capacity of CD133-positive human glioma-derived cancer stem cells (CSCs). Propagation of the glioma-derived CSCs in a hypoxic environment also led to the expansion of cells bearing CXCR4 (CD184), CD44(low) and A2B5 surface markers. The enhanced self-renewal activity of the CD133-positive CSCs in hypoxia was preceded by upregulation of HIF-1alpha. Knockdown of HIF-1alpha abrogated the hypoxia-mediated CD133-positive CSC expansion. Inhibition of the phosphatidylinositol 3-kinase(PI3K)-Akt or ERK1/2 pathway reduced the hypoxia-driven CD133 expansion, suggesting that these signaling cascades may modulate the hypoxic response. Finally, CSCs propagated at hypoxia robustly retained the undifferentiated phenotype, whereas CSCs cultured at normoxia did not. These results suggest that response to hypoxia by CSCs involves the activation of HIF-1alpha to enhance the self-renewal activity of CD133-positive cells and to inhibit the induction of CSC differentiation. This study illustrates the importance of the tumor microenvironment in determining cellular behavior.

Adaptive therapy

A number of successful systemic therapies are available for treatment of disseminated cancers. However, tumor response is often transient, and therapy frequently fails due to emergence of resistant populations. The latter reflects the temporal and spatial heterogeneity of the tumor microenvironment as well as the evolutionary capacity of cancer phenotypes to adapt to therapeutic perturbations. Although cancers are highly dynamic systems, cancer therapy is typically administered according to a fixed, linear protocol. Here we examine an adaptive therapeutic approach that evolves in response to the temporal and spatial variability of tumor microenvironment and cellular phenotype as well as therapy-induced perturbations. Initial mathematical models find that when resistant phenotypes arise in the untreated tumor, they are typically present in small numbers because they are less fit than the sensitive population. This reflects the "cost" of phenotypic resistance such as additional substrate and energy used to up-regulate xenobiotic metabolism, and therefore not available for proliferation, or the growth inhibitory nature of environments (i.e., ischemia or hypoxia) that confer resistance on phenotypically sensitive cells. Thus, in the Darwinian environment of a cancer, the fitter chemosensitive cells will ordinarily proliferate at the expense of the less fit chemoresistant cells. The models show that, if resistant populations are present before administration of therapy, treatments designed to kill maximum numbers of cancer cells remove this inhibitory effect and actually promote more rapid growth of the resistant populations. We present an alternative approach in which treatment is continuously modulated to achieve a fixed tumor population. The goal of adaptive therapy is to enforce a stable tumor burden by permitting a significant population of chemosensitive cells to survive so that they, in turn, suppress proliferation of the less fit but chemoresistant subpopulations. Computer simulations show that this strategy can result in prolonged survival that is substantially greater than that of high dose density or metronomic therapies. The feasibility of adaptive therapy is supported by in vivo experiments. [Cancer Res 2009;69(11):4894-903] Major FindingsWe present mathematical analysis of the evolutionary dynamics of tumor populations with and without therapy. Analytic solutions and numerical simulations show that, with pretreatment, therapy-resistant cancer subpopulations are present due to phenotypic or microenvironmental factors; maximum dose density chemotherapy hastens rapid expansion of resistant populations. The models predict that host survival can be maximized if "treatment-for-cure strategy" is replaced by "treatment-for-stability." Specifically, the models predict that an optimal treatment strategy will modulate therapy to maintain a stable population of chemosensitive cells that can, in turn, suppress the growth of resistant populations under normal tumor conditions (i.e., when therapy-induced toxicity is absent). In vivo experiments using OVCAR xenografts treated with carboplatin show that adaptive therapy is feasible and, in this system, can produce long-term survival.

NSC606985 induces apoptosis, exerts synergistic effects with cisplatin, and inhibits hypoxia-stabilized HIF-1alpha protein in human ovarian cancer cells

The camptothecins, which target the intranuclear enzyme topoisomerase I, have advanced to the forefront of several areas of developmental chemotherapy of cancers. In the present study, we investigated the potential anti-human ovarian cancer effects of NSC606985, a novel and rarely studied camptothecin analog, and its combination with cisplatin (CDDP). Human ovarian cancer cell line COC1 cells were treated with different nanomolar of NSC606985 with or without CDDP, and cell growth and apoptosis were evaluated, respectively, by MTT assay and annexin-V assay on flow cytometry. Chou-Talalay analysis was used to evaluate combined effect of NSC606985 and CDDP. Western blot was used to detect protein kinase Cdelta (PKCdelta), caspase-3 and hypoxia-inducible factor-1alpha (HIF-1alpha) proteins. Our results showed that NSC606985 at nanomolar concentration induced apoptosis with the activation of PKCdelta in COC1 cells. Especially, NSC606985 presented the significant combined effects on COC1 cells in terms of growth inhibition and apoptosis induction. In addition, NSC606985 significantly antagonized the accumulation of HIF-1alpha stabilized by hypoxia or hypoxia-mimetic agent. These results suggest that NSC606985 and its combination with CDDP present the therapeutic potential on ovarian cancer, and deserve further preclinical and clinical studies.

VEGF-A and i-NOS expression are prognostic factors in serous epithelial ovarian carcinomas after complete surgical resection

AIMS

Clinical stage at the time of diagnosis and achievement of complete macroscopic resection during initial surgery are key factors determining the outcome of ovarian cancer. However, prediction of outcome lacks accuracy and more reliable prognostic factors are required. Therefore, an analysis and evaluation of key angiogenic factors was carried out to determine their diagnostic and prognostic value in serous ovarian cancer.

METHODS

Expression levels of vascular endothelial growth factor (VEGF)-A, hypoxia-inducible factor (HIF)1-alpha and inducible nitric oxide synthase (i-NOS) were analysed by immunohistochemistry in a homogenous group of 112 patients with serous adenocarcinoma of the ovary. Vascular density as an indicator of angiogenesis was assessed using the Chalkley eyepiece method after staining for CD34. The correlation of these data with survival and established prognostic factors such as histological grade, Federation of Gynecology and Obstetrics (FIGO) stage, and residual tumour after surgery, was evaluated. Survival analyses, multivariate analyses and correlation tests were performed.

RESULTS

In the patient group with macroscopic complete tumour resection (R0) there was a significant correlation between VEGF-A and i-NOS expression. Kaplan-Meier analysis further revealed improved progression-free survival for R0 patients with VEGF-A-positive and i-NOS-negative tumours. The predictive relevance of VEGF-A regarding progression-free survival was sustained in multivariate analysis using FIGO stage, grading and resection status as fixed variables.

CONCLUSION

VEGF-A and i-NOS are prognostic markers for clinical outcome in serous ovarian cancer patients with macroscopic complete tumour resection (R0). Hence, pre-therapeutic assessment of VEGF-A as predictive factor for an antiangiogenic therapy might be of clinical value.