Peritoneal and subperitoneal stroma may facilitate regional spread of ovarian cancer.

PURPOSE: Epithelial ovarian cancer (EOC) is characterized by early peritoneal involvement ultimately contributing to morbidity and mortality. To study the role of the peritoneum in fostering tumor invasion, we analyzed differences between the transcriptional repertoires of peritoneal tissue lacking detectable cancer in patients with EOC versus benign gynecologic disease. EXPERIMENTAL DESIGN: Specimens were collected at laparotomy from patients with benign disease (b) or malignant (m) ovarian pathology and comprised primary ovarian tumors, paired bilateral specimens from adjacent peritoneum and attached stroma (PE), subjacent stroma (ST), peritoneal washes, ascites, and peripheral blood mononuclear cells. Specimens were immediately frozen. RNA was amplified by in vitro transcription and cohybridized with reference RNA to a custom-made 17.5k cDNA microarray. RESULTS: Principal component analysis and unsupervised clustering did not segregate specimens from patients with benign or malignant pathology. Class comparison identified differences between benign and malignant PE and ST specimens deemed significant by permutation test (P = 0.027 and 0.012, respectively). A two-tailed Student's t test identified 402 (bPE versus mPE) and 663 (mST versus bST) genes differentially expressed at a significance level of P2 < or = 0.005 when all available paired samples from each patient were analyzed. The same comparison using one sample per patient reduced the pool of differentially expressed genes but retained permutation test significance for bST versus mST (P = 0.031) and borderline significance for bPE versus mPE (P = 0.056) differences. CONCLUSIONS: The presence of EOC may foster peritoneal implantation and growth of cancer cells by inducing factors that may represent molecular targets for disease control.

Cellular tumor vaccines administered after T cell-depleted allogeneic bone marrow transplantation induce effective anti-tumor immune responses.

In allogeneic hematopoietic stem cell (HSC) transplantation, graft vs. tumor (GVT) activity contributes to the cancer cure. It is closely associated with graft vs. host disease (GVHD), an immune response initiated by transplanted donor T-cell responses against host minor histocompatibility antigens (mHAgs). GVHD is prevented by T-cell depletion of the donor graft, but T-cell depletion also abrogates curative GVT. We wished to test the hypothesis that cellular tumor vaccines administered after T cell-depleted HSC transplant can induce significant GVT effects, despite the absence of transplanted mature donor T cells. In this investigation, a murine model of major histocompatibility complex (MHC)-matched, mHAg-mismatched allogeneic HSC transplant was studied. T cell-depleted or normal T cell-containing grafts were given to myeloablated recipients. Following reconstitution the recipients were vaccinated with tumor vaccines. GVT responses were measured in vitro by T-cell function assays and flow cytometry, and in vivo by tumor burden or survival. Post-transplant tumor vaccines induced effective anti-tumor responses in recipients of T cell-depleted transplants, producing cytolytic and cytokine responses, reduced tumor burden and prolonged survival. Recipients of T cell-depleted transplants that still have significant thymic function may be suitable subjects for post-transplant vaccine therapy.

Pilot study of Flt3 ligand comparing intraperitoneal with subcutaneous routes on hematologic and immunologic responses in patients with peritoneal carcinomatosis and mesotheliomas.

PURPOSE: This study compared the clinical toxicity and hematological effects of i.p. and s.c. administration of fms-like tyrosine kinase-3-ligand (Flt3-L; Amgen, Thousand Oaks, CA), a truncated glycoprotein that increases dendritic cells (DCs) and monocytes. EXPERIMENTAL DESIGN: Patients with peritoneal carcinomatosis or mesothelioma were randomly assigned to treatment with Flt3-L (25 micro g/kg, maximum 1500 micro g), i.p. or s.c., days 1-5 and 8-12, then changed to the alternative route at 4 weeks. Treatment was continued s.c. or i.p. at 8 weeks. RESULTS: Fifteen patients (14 evaluable) were randomized to receive i.p. (n = 8) or s.c. (n = 7) injections. Their median age was 55 years (range, 40-68 years). Primary tumors were as follows: ovarian/peritoneal cancer (n = 9); gastrointestinal cancer (n = 2); and mesothelioma (n = 4). Treatment was well tolerated without serious toxicity (24 i.p. cycles; 32 s.c. cycles). Treatment (i.p. or s.c.) resulted in significant increases in WBCs (WBC, monocytes, and Lin(-)DR(+) DCs), and platelets (during washout). Both interleukin (IL)-12(p70) and IL-10 were secreted by monocyte-derived DCs after in vitro exposure to maturation factors. Increased IL-12 versus IL-10 secretion responses and higher proportions of the CD11c(+) DC subset in post-Flt3-L specimens suggested a maturational shift toward the monocyte-derived DC phenotype had occurred. Three patients (2 with mesothelioma and 1 with gastrointestinal cancer) had stable disease for 8, 8, and 12+ months, respectively. CONCLUSIONS: Flt3-L, administered either i.p. or s.c., is well tolerated and produced similar increases in monocytes, DCs, and platelets. DCs from peripheral blood and peritoneal fluids showed cell surface phenotypic and cytokine maturational responses to activation stimuli. These findings suggested that Flt3-L, in combination with suitable activating agents, could be developed further in patients with epithelial ovarian cancer.

Neuroendocrine modulation of signal transducer and activator of transcription-3 in ovarian cancer.

There is growing evidence that chronic stress and other behavioral conditions are associated with cancer pathogenesis and progression, but the mechanisms involved in this association are poorly understood. We examined the effects of two mediators of stress, norepinephrine and epinephrine, on the activation of signal transducer and activator of transcription-3 (STAT3), a transcription factor that contributes to many promalignant pathways. Exposure of ovarian cancer cell lines to increasing concentrations of norepinephrine or epinephrine showed that both independently increased levels of phosphorylated STAT3 in a dose-dependent fashion. Immunolocalization and ELISA of nuclear extracts confirmed increased nuclear STAT3 in response to norepinephrine. Activation of STAT3 was inhibited by blockade of the beta1- and beta2-adrenergic receptors with propranolol, and by blocking protein kinase A with KT5720, but not with the alpha receptor blockers prazosin (alpha1) and/or yohimbine (alpha2). Catecholamine-mediated STAT3 activation was not inhibited by pretreatment with an anti-interleukin 6 (IL-6) antibody or with small interfering RNA (siRNA)-mediated decrease in IL-6 or gp130. Regarding the effects of STAT3 activation, exposure to norepinephrine resulted in an increase in invasion and matrix metalloproteinase (MMP-2 and MMP-9) production. These effects were completely blocked by STAT3-targeting siRNA. In mice, treatment with liposome-incorporated siRNA directed against STAT3 significantly reduced isoproterenol-stimulated tumor growth. These studies show IL-6-independent activation of STAT3 by norepinephrine and epinephrine, proceeding through the beta1/beta2-adrenergic receptors and protein kinase A, resulting in increased matrix metalloproteinase production, invasion, and in vivo tumor growth, which can be ameliorated by the down-regulation of STAT3.