Angiogenesis inhibitors in the treatment of epithelial ovarian cancer

Successful treatment of ovarian cancer with apatinib combined with chemotherapy: A case report

RATIONALE

The standard treatment for ovarian cancer is chemotherapy with 2 drugs (taxanes and platinum drugs). However, the traditional combination of the 2 drugs has many adverse effects (AEs) and the cancer cells will quickly become resistant to the drugs. Apatinib is a small-molecule antiangiogenic agent which has shown promising therapeutic effects against diverse tumor types, but it still remains unknown whether apatinib has an antitumor effect in patients with ovarian cancer. Herein, we present a successfully treated case of ovarian cancer using chemotherapy and apatinib, in order to demonstrate the effectiveness of this new combined regimen in ovarian cancer.

PATIENTS CONCERNS

A 51-year-old Chinese woman presented with ovarian cancer >4.5 years. The disease and the cancer antigen 125 (CA-125) had been controlled well by surgical treatment and following chemotherapy. However, the drugs could not control the disease anymore as the CA-125 level was significantly increasing.

DIAGNOSIS

Ovarian cancer.

INTERVENTIONS

The patient was treated with apatinib combined with epirubicin. Apatinib was administered orally, at an initial daily dose of 500 mg, and was then reduced to 250 mg qd after the appearance of intolerable hand-foot syndrome (HFS) and oral ulcer. Then, the oral ulcer disappeared and the HFS was controlled by dose adjustment, oral vitamin B6, and hand cream application.

OUTCOMES

The CA-125 reverted to the normal value after treatment with the new regimen. Magnetic resonance imaging showed that the original tumor lesions had disappeared. Apatinib monotherapy as maintenance therapy was then used to successfully control the cancer with a complete response. Our study is the first, to our knowledge, to report the therapeutic effects of apatinib and epirubicin on ovarian cancer.

LESSONS

Apatinib combined with chemotherapy and apatinib monotherapy as maintenance therapy could be a new therapeutic strategy for ovarian cancer, especially adenocarcinomas.

Cinnamon extract reduces VEGF expression via suppressing HIF-1α gene expression and inhibits tumor growth in mice

Although many anti-VEGF agents are available for cancer treatment, side effects of these agents limit their application for cancer treatment and prevention. Here we studied the potential use of a diet-based agent as an inhibitor for VEGF production. Using a VEGF reporter assay, our data showed that an extract from cinnamon (CE) was a potent inhibitor of VEGF production in human cancer cells and suggested inhibition might be mediated through the suppression of HIF-1α gene expression and protein synthesis. Furthermore, CE treatment was found to inhibit expression and phosphorylation of STAT3 and AKT, which are key factors in the regulation of HIF-1α expression, and significantly reduce angiogenesis potential of cancer cells by migration assay. Consistent with these results, we observed significant suppression of VEGF expression, blood vessel formation, and tumor growth in a human ovarian tumor model in mice treated with CE. Cinnamaldehyde, a major component in cinnamon, was identified as one active component in CE that inhibits VEGF expression. Taken together, our findings provide a novel mechanism underlying anti-angiogenic and anti-tumor actions of CE and support the potential use of CE in cancer prevention and treatment. © 2016 Wiley Periodicals, Inc.

Targeting JAK1/STAT3 signaling suppresses tumor progression and metastasis in a peritoneal model of human ovarian cancer

JAK/STAT3 is one of the major signaling pathways that is aberrantly activated in ovarian cancer and associated with tumor progression and poor prognosis in patients with ovarian cancer. In this study, we evaluated the therapeutic potential of targeting JAK/STAT3 signaling in ovarian cancer using a peritoneal dissemination mouse model. We developed this mouse model by injecting a metastatic human ovarian cancer cell line, SKOV3-M-Luc, into the peritoneal cavity of immunodeficient mice. This model displayed a phenotype similar to late-stage ovarian cancer, including extensive peritoneal metastasis and ascites production. The constitutive activation of STAT3 in human ovarian cancer cells appeared to be mediated by an autocrine cytokine loop involving the IL6 family of cytokines and JAK1 kinase. shRNA-mediated knockdown of JAK1 or STAT3 in ovarian cancer cells led to reduced tumor growth, decreased peritoneal dissemination, and diminished ascites production, suggesting a critical role of STAT3 in ovarian cancer progression. Similar results were obtained when a small-molecule inhibitor (JAKi) of the JAK1 kinase was used to treat ovarian cancer in this model. In addition, we found that the expression level of IL6 was correlated with activation of STAT3 in ovarian cancer cells both in vitro and in vivo, suggesting a potential application of IL6 as a biomarker. Altogether, our results demonstrate that targeting JAK1/STAT3, using shRNA knockdown or a small-molecule inhibitor, effectively suppressed ovarian tumor progression and, therefore, could be a potential novel therapeutic approach for treating advanced ovarian cancer.

The search for biomarkers to direct antiangiogenic treatment in epithelial ovarian cancer

Antiangiogenic agents have demonstrated improved progression-free survival in women with primary and recurrent epithelial ovarian cancer (EOC). Biomarkers that predict outcomes in patients treated with antiangiogenic agents are being investigated to rationally direct therapy for women most likely to benefit from these agents. Among the most promising plasma-based biomarkers are vascular endothelial growth factor (VEGF)-A, fibroblast growth factor, platelet-derived growth factor, angiopoietin-2, and VEGF receptor-2. While these biomarkers have been correlated with prognosis, they have not been shown to predict benefit, specifically from anti-VEGF therapy, highlighting the need for alternative biomarkers, including molecular and clinical factors, which may be predictive of outcome in women with ovarian cancer treated with antiangiogenic agents. Biomarkers are currently being investigated as secondary outcomes in several ongoing phase II and phase III clinical trials of antiangiogenic agents in patients with EOC. Molecular techniques, such as microarray analyses, and imaging techniques, such as dynamic contrast-enhanced magnetic resonance imaging, positron emission tomography, and single photon emission computed tomography, are also being explored in this field. In this review, we provide a comprehensive overview of current biomarker research, with an emphasis on angiogenic biomarkers associated with EOC.

Observation of ovarian cancer stem cell behavior and investigation of potential mechanisms of drug resistance in three-dimensional cell culture

Cancer cells behave differently in a three-dimensional (3D) cell culture compared with in the conventional two-dimensional (2D) one. Accumulated evidences indicate that the characteristics of cancer stem cells (CSCs) are different from common cancer cells due to their ability to produce tumors and resist chemoradiation. The objective of this work was to observe CSC behavior and investigate the potential mechanisms of CSC drug resistance in 3D versus 2D in vitro environment. We first demonstrated that the CD44(+)CD117(+)cells isolated from the human epithelial ovarian cancer HO8910 cell line have the properties of CSCs that revealed faster growth, larger tumorsphere and stronger survival potential in the hypoxic environment in 3D cell culture as well as more powerful tumorigenicity in a xenograft mice than the HO8910 cells. The CD44(+)CD117(+)CSCs also exhibited high chemoresistance to anticancer drugs when the cells were incubated with 5-fluorouracil, cisplatin and carboplatin, respectively in 3D versus 2D environment. This might be associated with the high expression of ABCG2, ABCB1 and the high expression of MMP-2 and MMP-9 in CD44(+)CD117(+)CSCs. Overall, these results suggest the advantages of using 3D culture model to accurately display CSC behavior in vitro. 3D model may improve the efficacy of screening anticancer drugs for treatment of ovarian CSCs.

Angiogenesis-related pathways in the pathogenesis of ovarian cancer

Ovarian Cancer represents the most fatal type of gynecological malignancies. A number of processes are involved in the pathogenesis of ovarian cancer, especially within the tumor microenvironment. Angiogenesis represents a hallmark phenomenon in cancer, and it is responsible for tumor spread and metastasis in ovarian cancer, among other tumor types, as it leads to new blood vessel formation. In recent years angiogenesis has been given considerable attention in order to identify targets for developing effective anti-tumor therapies. Growth factors have been identified to play key roles in driving angiogenesis and, thus, the formation of new blood vessels that assist in "feeding" cancer. Such molecules include the vascular endothelial growth factor (VEGF), the platelet derived growth factor (PDGF), the fibroblast growth factor (FGF), and the angiopoietin/Tie2 receptor complex. These proteins are key players in complex molecular pathways within the tumor cell and they have been in the spotlight of the development of anti-angiogenic molecules that may act as stand-alone therapeutics, or in concert with standard treatment regimes such as chemotherapy. The pathways involved in angiogenesis and molecules that have been developed in order to combat angiogenesis are described in this paper.