Endoglin (CD105) contributes to platinum resistance and is a target for tumor-specific therapy in epithelial ovarian cancer.

PURPOSE: Endoglin (CD105) is a membranous protein overexpressed in tumor-associated endothelial cells, chemoresistant populations of ovarian cancer cells, and potentially stem cells. Our objective was to evaluate the effects and mechanisms of targeting endoglin in ovarian cancer. EXPERIMENTAL DESIGN: Global and membranous endoglin expression was evaluated in multiple ovarian cancer lines. In vitro, the effects of siRNA-mediated endoglin knockdown with and without chemotherapy were evaluated by MTT assay, cell-cycle analysis, alkaline comet assay, γ-H2AX foci formation, and quantitative PCR. In an orthotopic mouse model, endoglin was targeted with chitosan-encapsulated siRNA with and without carboplatin. RESULTS: Endoglin expression was surprisingly predominantly cytoplasmic, with a small population of surface-positive cells. Endoglin inhibition decreased cell viability, increased apoptosis, induced double-stranded DNA damage, and increased cisplatin sensitivity. Targeting endoglin downregulates expression of numerous DNA repair genes, including BARD1, H2AFX, NBN, NTHL1, and SIRT1. BARD1 was also associated with platinum resistance, and was induced by platinum exposure. In vivo, antiendoglin treatment decreased tumor weight in both ES2 and HeyA8MDR models when compared with control (35%-41% reduction, P < 0.05). Endoglin inhibition with carboplatin was associated with even greater inhibitory effect when compared with control (58%-62% reduction, P < 0.001). CONCLUSIONS: Endoglin downregulation promotes apoptosis, induces significant DNA damage through modulation of numerous DNA repair genes, and improves platinum sensitivity both in vivo and in vitro. Antiendoglin therapy would allow dual treatment of both tumor angiogenesis and a subset of aggressive tumor cells expressing endoglin and is being actively pursued as therapy in ovarian cancer.

Uterine leiomyosarcoma diffusely express disialoganglioside GD2 and bind the therapeutic immunocytokine 14.18-IL2: implications for immunotherapy.

Uterine leiomyosarcoma comprises <1 % of uterine malignancies and is known for its clinically aggressive course. Extrapelvic recurrences are common and often lethal. No adjuvant therapies have been shown to significantly improve overall survival, highlighting the need for new and novel therapies. Our objective was to determine whether GD2-specific immunocytokine therapy may be explored for the treatment for uterine leiomyosarcoma. To do so, frozen tissue sections were obtained from the Gynecologic Oncology Group tumor bank and evaluated by immunohistochemistry (IHC) for GD2 expression using both the parent mouse monoclonal antibody 14G2A and immunocytokine 14.18-IL2 generated from the 14G2A sequence. Immunoreactivity was detected by avidin-biotin complex with DAB substrate. Specimens were reviewed by a pathologist with light microscopy and classified as negative, 1+, 2+ or 3+, compared to human melanoma cells as positive control and tissue incubated in the absence of primary antibody as negative control. GD2 was diffusely present in all evaluable samples. 10 tumors (67 %) demonstrated 3+ IHC intensity for GD2, two tumors (13 %) demonstrated 2+ intensity, and 3 (20 %) tumors demonstrated 1+ intensity. Eleven cases had sufficient tissue to assess 14.18-IL2 binding. All 11 cases bound 14.18-IL2 in a pattern identical to the parent antibody. Uterine leiomyosarcoma diffusely express GD2 and bind the therapeutic immunocytokine 14.18-IL2. This warrants further exploration to determine whether immunocytokine therapy may have a clinical role in the management of these aggressive tumors.

Completed versus aborted radical hysterectomy for node-positive stage IB cervical cancer in the modern era of chemoradiation therapy.

OBJECTIVE: Debate continues about optimal management of patients with node-positive stage I cervical cancer. Our objective was to determine if patient outcomes are affected by radical hysterectomy in the modern era of adjuvant chemoradiation. METHODS: Cervical cancer patients diagnosed from 2000 to 2008 were identified. Demographics, therapy, clinicopathologic data, progression free survival (PFS), overall survival (OS), total radiation exposure, and grade 3-4 complications were analyzed by student t, Mann-Whitney, Fisher's exact, Kaplan-Meier, and log rank tests. RESULTS: This single-institution review evaluated forty-one of 334 (13.4%) patients scheduled to undergo radical hysterectomy that had gross nodal disease diagnosed intraoperatively. 15 underwent aborted radical hysterectomy following lymphadenectomy; the remaining 26 underwent radical hysterectomy and lymphadenectomy. Eleven patients undergoing radical hysterectomy underwent whole pelvic radiation therapy (WPRT) while 8 (30.7%) patients underwent WPRT and postoperative vaginal brachytherapy (BT) for local treatment secondary to close margins. All patients undergoing aborted radical hysterectomy underwent WPRT and BT. With mean follow-up of 42.3 months, there were no significant differences in urinary, gastrointestinal, or hematologic complications between groups. When comparing those undergoing radical hysterectomy to aborted radical hysterectomy, there were no significant differences in local recurrence (11.5% vs 26.7%, p=0.39) or distant recurrence (19.2% vs. 33.3%, p=0.45), PFS (74.9 months vs 46.8 months, p=0.106), or OS (91.8 months vs 69.4 months, p=0.886). CONCLUSIONS: Treatment of patients with early stage cervical cancer and nodal metastasis may be tailored intraoperatively. Completion of radical hysterectomy and lymphadenectomy decreases radiation exposure without apparently compromising safety or outcome in the era of adjuvant chemoradiation.

Molecular/genetic therapies in ovarian cancer: future opportunities and challenges.

Ovarian cancer is the most lethal gynecologic cancer. Traditional therapies have included surgical management and cytotoxic chemotherapy; however, treatment paradigms continue to shift from empiric cytotoxic chemotherapy to more individualized treatment. Recent research efforts have focused on determining and targeting the molecular biological mechanisms of ovarian cancer in an attempt to develop novel therapeutic modalities with the ultimate goal of improving outcome while limiting toxicity. This chapter reviews progress in the development of novel therapies directed at major pathways implicated in ovarian tumorigenesis including angiogenesis, PARP inhibition, signal transduction, antifolate therapies, death receptor-mediated therapies, histone deacetylase inhibition, immunotherapeutics, and oncolytics.