Association with albumin as a means to improve biodistribution and tumor deposition of a Fab was investigated using AB.Fab4D5, a bifunctional molecule derived from trastuzumab (HERCEPTIN) capable of binding albumin and tumor antigen HER2 (erbB2) simultaneously. AB.Fab4D5 was compared with trastuzumab and a trastuzumab-derived Fab (Fab4D5) for the ability to target tumors overexpressing HER2 in mouse mammary tumor virus/HER2 allograft models. Biodistribution was monitored using intravital microscopy, histology, and integrated single-photon emission computed tomography/ computed tomography analysis. Fab4D5 tumor deposition was characterized by rapid but transient appearance in tumor at 2 h with little retention, followed by rapid accumulation in kidney by 6 h. Trastuzumab was slow to accumulate in tumors and slow to clear from normal tissues, although significant tumor deposition was achieved by 24 h. In contrast, AB.Fab4D5 was observed at 2 h in tumor and its presence was sustained beyond 24 h similar to trastuzumab. Intravital microscopy revealed that at peak tumor accumulation, tumor cell staining by AB.Fab4D5 was more uniform than for Fab4D5 or trastuzumab. Similar tumor deposition was achieved for both AB.Fab4D5 and trastuzumab at 48 h (35.9 F 1.8% and 38.2 F 3.1% injected dose/g); however, AB.Fab4D5 targeted tumors more rapidly and quickly cleared from blood, leading to a lower overall normal tissue exposure. Importantly, unlike Fab4D5, AB.Fab4D5 did not accumulate in kidney, suggesting that association with albumin leads to an altered route of clearance and metabolism. Rapid targeting, excellent tumor deposition and retention, coupled with high tumor to blood ratios may make AB.Fab an exceptional molecule for imaging and cancer therapy. [Cancer Res 2007;67(1):254-61]

The hepatocyte growth factor (HGF) and its receptor, c-Met, have been implicated in driving proliferation, invasion, and poor prognosis in pancreatic cancer. Here, we investigated the expression of HGF and c-Met in primary pancreatic cancers and described in vitro and in vivo models in which MetMAb, a monovalent antibody against c-Met, was evaluated. First, expression of HGF and MET mRNA was analyzed in 59 primary pancreatic cancers and 51 normal samples, showing that both factors are highly expressed in pancreatic cancer. We next examined HGF responsiveness in pancreatic cancer lines to select lines that proliferate in response to HGF. Based on these studies, two lines were selected for further in vivo model development: BxPC-3 (c-Met + , HGF À ) and KP4 (c-Met + , HGF + ) cells. As BxPC-3 cells are responsive to exogenous HGF, s.c. tumor xenografts were grown in a paracrine manner with purified human HGF provided by osmotic pumps, wherein MetMAb treatment significantly inhibited tumor growth. KP4 cells are autocrine for HGF and c-Met, and MetMAb strongly inhibited s.c. tumor growth. To better model pancreatic cancer and to enable long-term survival studies, an orthotopic model of KP4 was established. MetMAb significantly inhibited orthotopic KP4 tumor growth in 4-week studies monitored by ultrasound and also improved survival in 90-day studies. MetMAb significantly reduced c-Met phosphorylation in orthotopic KP4 tumors with a concomitant decrease in Ki-67 staining. These data suggest that the HGF/c-Met axis plays an important role in the progression of pancreatic cancer and that targeting c-Met therein may have therapeutic value.

Despite efforts to eliminate it at the societal level, HIV stigma persists and continues to threaten the health of people living with HIV (PLWH). We tested whether social support, adaptive coping, and/or HIV identity centrality act as resilience resources by buffering people from the negative impact of enacted and/or anticipated stigma on stress and ultimately HIV symptoms. Ninety-three PLWH completed a survey, and data analyses tested for evidence of mediation and moderation. Results demonstrated that instrumental social support, perceived community support, and HIV identity centrality buffered participants from the association between anticipated stigma and HIV symptoms. That is, anticipated stigma was associated with HIV symptoms via stress only at low levels of these resources. No resources buffered participants from the impact of enacted stigma. Identifying and enhancing resilience resources among PLWH is critical for protecting PLWH from the harmful effects of stigma.

We describe an mRNA profiling technique for determining differential gene expression that utilizes, but does not require, prior knowledge of gene sequences. This method permits high-throughput reproducible detection of most expressed sequences with a sensitivity of greater than 1 part in 100,000. Gene identification by database query of a restriction endonuclease fingerprint, confirmed by competitive PCR using gene-specific oligonucleotides, facilitates gene discovery by minimizing isolation procedures. This process, called GeneCalling, was validated by analysis of the gene expression profiles of normal and hypertrophic rat hearts following in vivo pressure overload.

Vascular endothelial growth factor (VEGF), a major regulator of angiogenesis, has therapeutic benefit in animal models of coronary or limb ischemia. However, the hemodynamic effects of VEGF have not been investigated. We examined the effects of VEGF on hemodynamics and cardiac performance. Mean arterial pressure (MAP), heart rate (HR), cardiac output, stroke volume, left ventricular (LV) dP/dt, and hematocrit were measured before and after intravenous injection of VEGF in conscious, instrumented rats. VEGF caused a dose-dependent reduction in MAP and an associated increase in HR. VEGF (250 micrograms/kg) significantly decreased cardiac output and stroke volume without affecting the inotropic state of the left ventricle, as determined by dP/dt. VEGF significantly increased hematocrit. Furthermore, VEGF did not affect contractility or HR in the isolated rat heart in vitro. The data suggest that the VEGF-induced decrease in cardiac output is due to reduced stroke volume, which may be caused by a decrease in venous return rather than a direct effect on myocardial contractility. In addition, pretreatment with N omega-nitro-L-arginine methyl-ester (L-NAME), a nitric oxide (NO) synthase inhibitor, significantly attenuated the depressor and tachycardic responses to VEGF, suggesting that VEGF-induced hypotension may be mediated by NO.