Quantification of VGF- and pro-SAAS-derived peptides in endocrine tissues and the brain, and their regulation by diet and cold stress.

Two novel granin-like polypeptides, VGF and pro-SAAS, which are stored in and released from secretory vesicles and are expressed widely in nervous, endocrine, and neuroendocrine tissues, play roles in the regulation of body weight, feeding, and energy expenditure. Both VGF and pro-SAAS are cleaved into peptide fragments, several of which are biologically active. We utilized a highly sensitive and specific radioimmunoassay (RIA) to immunoreactive, pro-SAAS-derived PEN peptides, developed another against immunoreactive, VGF-derived AQEE30 peptides, and quantified these peptides in various mouse tissues and brain regions. Immunoreactive AQEE30 was most abundant in the pituitary, while brain levels were highest in hypothalamus, striatum, and frontal cortex. Immunoreactive PEN levels were highest in the pancreas and spinal cord, and in brain, PEN was most abundant in striatum, hippocampus, pons and medulla, and cortex. Since both peptides were expressed in hypothalamus, a region of the brain that controls feeding and energy expenditure, double label immunofluorescence studies were employed. These demonstrated that 42% of hypothalamic arcuate neurons coexpress VGF and SAAS peptides, and that the intracellular distributions of these peptides in arcuate neurons differed. By RIA, cold stress increased immunoreactive AQEE30 and PEN peptide levels in female but not male hypothalamus, while a high fat diet increased AQEE30 and PEN peptide levels in female but not male hippocampus. VGF and SAAS-derived peptides are therefore widely expressed in endocrine, neuroendocrine, and neural tissues, can be accurately quantified by RIA, and are differentially regulated in the brain by diet and cold stress.

Initial clinical experience evaluating Yttrium-90-chimeric T84.66 anticarcinoembryonic antigen antibody and autologous hematopoietic stem cell support in patients with carcinoembryonic antigen-producing metastatic breast cancer.

cT84.66 is a human/murine IgG1 with high affinity and specificity for carcinoembryonic antigen (CEA). An earlier Phase I trial defined the maximum tolerated dose for 90Y-diethylenetriaminepentaacetic acid (DTPA)-cT84.66 at 22 mCi/m2. Dose-limiting toxicities were reversible leukopenia and thrombocytopenia. The purpose of this Phase I trial was to evaluate the feasibility and toxicities of administering higher activities of 90Y-DTPA-cT84.66 with stem cell support in patients with CEA-producing breast cancer. Patients with CEA-producing breast cancer refractory to standard therapies underwent peripheral stem cell collection followed by infusion of 111indium-DTPA-cT84.66. Those patients demonstrating tumor targeting received a single therapy dose of 90Y-DTPA-cT84.66, followed by Ca-DTPA infusion for 72 h posttherapy. Stem cells were reinfused following a divided schedule. To date, seven patients have been accrued to this trial. Each patient received an imaging dose of (111)In-cT84.66. Six patients demonstrated tumor imaging and received a single cycle of 90Y-cT84.66 at 15 mCi/m2 (three patients) and 22.5 mCi/m2 (three patients). One patient did not demonstrate tumor imaging and was not treated. At these administered activities, 90Y-cT84.66 was well tolerated. No dose-limiting toxicities have been observed. All patients demonstrated hematopoietic recovery after stem cell infusion. One patient demonstrated stable disease for 4 months; one patient had stable disease and reduction of bone pain for 3 months; and a third patient experienced >50% reduction of an ovarian metastasis, resolution of malignant pleural effusion, stable pleural metastases, and stable bone scan for 14 months. Preliminary results from this ongoing Phase I trial are promising and demonstrate the feasibility and potential for antitumor effects of stem cell supported 90Y-cT84.66 therapy in patients with CEA-producing breast cancers.