Background: Murine studies suggest that myeloid cells such as vascular leukocytes (VLC) and Tie2 + monocytes play a critical role in tumor angiogenesis and vasculogenesis. Myeloid cells are a primary cause of resistance to anti-VEGF therapy. The elimination of these cells from the tumor microenvironment significantly restricts tumor growth in both spontaneous and xenograft murine tumor models. Thus animal studies indicate that myeloid cells are potential therapeutic targets for solid tumor therapy. Abundant VLC and Tie2 + monocytes have been reported in human cancer. Unfortunately, the importance of VLC in human cancer growth remains untested as there are no confirmed therapeutics to target human VLC.
Ovarian cancer is the most lethal of gynecologic malignancies. Currently, standard treatment for epithelial ovarian cancer consists of surgical debulking followed by adjuvant chemotherapy with a platinum-based drug coupled with paclitaxel. While initial response to chemotherapy is high, the majority of patients develop recurrent disease which is characterized by chemoresistance. The primary cytotoxic effect of many chemotherapy drugs is mediated by apoptotic response in tumor cells. Recent data indicates that cross talk between the tumor microenvironment and malignant epithelial cells can influence apoptotic response as well. The identification of molecules involved in the regulation and execution of apoptosis, and their alterations in ovarian carcinoma have provided new insights into the mechanism behind the development of chemoresistance in this disease. Our challenge is now to devise strategies to circumvent cell death defects and ultimately improve response to treatment in ovarian carcinoma patients.
Human tumor vessels express tumor vascular markers (TVMs), proteins that are not expressed in normal blood vessels. Antibodies targeting TVMs could act as potent therapeutics. Unfortunately, preclinical in vivo studies testing anti-human TVM therapies have been difficult to perform due to a lack of in vivo models with confirmed expression of human TVMs. We therefore evaluated TVM expression in a human embryonic stem cell derived teratoma (hESCT) tumor model previously shown to have human vessels. We now report that, in the presence of tumor cells, hESCT tumor vessels express human TVMs. The addition of mouse embryonic fibroblasts and human tumor endothelial cells significantly increases the number of human tumor vessels. TVM induction is mostly tumor type specific with ovarian cancer cells inducing primarily ovarian TVMs while breast cancer cells induce breast cancer specific TVMs. We demonstrate the utility of this model to test an anti-human specific TVM immunotherapeutics; anti-human Thy-1 TVM immunotherapy results in central tumor necrosis and a three-fold reduction in human tumor vascular density. Finally, we tested the ability of the hESCT model, with human tumor vascular niche, to enhance the engraftment rate of primary human ovarian cancer stem-like cells (CSC). ALDH+ CSC from patients (n=6) engrafted in hESCT within 4–12 weeks whereas none engrafted in the flank. ALDH- ovarian cancer cells showed no engraftment in the hESCT or flank (n=3). Thus this model represents a useful tool to test anti-human TVM therapy and evaluate in vivo human CSC tumor biology.
IntroductionTo describe patient-reported outcomes and toxicities at time of treatment discontinuation secondary to progression or toxicities in advanced/recurrent cervical cancer patients receiving chemotherapy with bevacizumab.MethodsSummarize toxicity, grade, and health-related quality of life within 1 month of treatment discontinuation for women receiving chemotherapy with bevacizumab in GOG240.ResultsOf the 227 patients who received chemotherapy with bevacizumab, 148 discontinued study protocol treatment (90 for disease progression and 58 for toxicity). The median survival time from treatment discontinuation to death was 7.9 months (95% CI 5.0 to 9.0) for those who progressed versus 12.1 months (95% CI 8.9 to 23.2) for those who discontinued therapy due to toxicities. The most common grade 3 or higher toxicities included hematologic, gastrointestinal, and pain. Some 57% (84/148) of patients completed quality of life assessment within 1 month of treatment discontinuation. Those patients who discontinued treatment due to progression had a mean decline in the FACT-Cx TOI of 3.2 points versus 2.2 in patients who discontinued therapy due to toxicity. This was a 9.9 point greater decline in the FACT-Cx TOI scores than those who discontinued treatment due to progression (95% CI 2.8 to 17.0, p=0.007). The decline in quality of life was due to worsening physical and functional well-being. Those who discontinued treatment due to toxicities had worse neurotoxicity and pain.DiscussionPatients who discontinued chemotherapy with bevacizumab for toxicity experienced longer post-protocol survival but significantly greater declination in quality of life than those with progression. Future trial design should include supportive care interventions that optimize physiologic function and performance status for salvage therapies.
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