No abstract

It has been recently reported that treatment with an anti-placenta growth factor (PlGF) antibody inhibits metastasis and primary tumor growth. Here we show that, although anti-PlGF treatment inhibited wound healing, extravasation of B16F10 cells, and growth of a tumor engineered to overexpress the PlGF receptor (VEGFR-1), neutralization of PlGF using four novel blocking antibodies had no significant effect on tumor angiogenesis in 15 models. Also, genetic ablation of the tyrosine kinase domain of VEGFR-1 in the host did not result in growth inhibition of the anti-VEGF-A sensitive or resistant tumors tested. Furthermore, combination of anti-PlGF with anti-VEGF-A antibodies did not result in greater antitumor efficacy than anti-VEGF-A monotherapy. In conclusion, our data argue against an important role of PlGF during primary tumor growth in most models and suggest that clinical evaluation of anti-PlGF antibodies may be challenging.

The prostate and seminal vesicle (SV) are androgen-dependent secretory glands of the male genital tract. The epithelial cells of these glands produce the bulk of the seminal secretions. The objective of the present study was to examine the ontogeny of cytokeratin and androgen receptor (AR) expression in the rat SV, anterior prostate (AP) and ventral prostate (VP). The study utilized organ culture to examine the effects of androgens on the development of these markers and castration of adult rats to examine androgenic effects on their maintenance. Tissues were examined from 14 days of gestation to adulthood. The SV was a tubular organ from its inception while the prostate formed from solid epithelial cords. These prostatic buds canalized in a proximal to distal manner starting at day 1 postnatal in the VP and day 5 in the AP. The expression of cytokeratins and AR was visualized by immunocytochemistry. In all three glands keratins 5, 7, 8, 14, 18 and 19 were initially uniformly expressed in all epithelial cells. In the SV, segregation of cytokeratins between the luminal and basal cell types started at 4 days postnatally with keratin 7 localizing to basal cells. Five days after birth, keratins 5 and 14 were also localized to the basal epithelium, while keratins 8 and 18 were only expressed by luminal cells. Keratin 19 was expressed in all epithelial cells throughout development and into adulthood. In the VP and AP the same pattern of cytokeratin segregation occurred as in the SV. Epithelial differentiation occurred in a proximal to distal fashion in the prostate. In the proximal VP ducts keratins 7 and 14 were basally localized by 2 days postnatally, while keratin 5 did not clearly segregate to basal cells until day 9 after birth. In the AP keratin 14 was basally localized by 1 day postnatal but keratin 5 and 7 did not colocalize to the basal cells until days 9 and 12, respectively. AR were expressed in the epithelium of the urogenital sinus from 19 days of gestation. At 19 and 20 days of embryonic development AR-negative prostatic buds were seen emerging from the AR-positive urogenital sinus epithelium. By birth AR were detectable in the epithelium of both prostatic lobes and the S V The role of androgens in the development of the prostatic and SV epithelium was investigated in a serum-free organ culture system. These experiments showed that differentiation of prostatic and SV luminal and basal epithelial cell types was accelerated as compared to the in vivo situation in the presence of androgens, and did not occur in their absence. Following castration of adult animals the prostate and SV regressed with preferential loss of luminal epithelium. The relative numbers of basal cells was increased, though some flattened cells expressing a luminal cell pattern of cytokeratins were still observed. AR were detected in the prostatic and SV epithelium of long-term castrated animals. In summary, the rat prostate was found to be derived from undifferentiated solid epithelial cords. Canalization occurred concurrent with the di...

The prostate and seminal vesicle (SV) are androgen-dependent secretory glands of the male genital tract. They produce the bulk of the seminal secretions. The object of the present study was to examine and document the ontogeny of stromal maturation in the rat anterior and ventral prostate and SV. These organs have a loosely organized cellular mesenchyme during fetal development. During prostatic development the mesenchyme condensed to form smooth muscle sheaths immediately surrounding the epithelium, with looser connective tissue between individual ducts. In the SV, a loose connective tissue layer called the lamina propria lies between the epithelium and developing muscle. Smooth muscle oc-actin, myosin, desmin, laminin, vinculin, vimentin and androgen receptor (AR) expression were examined by immunocytochemical methods during the pre- and postnatal developmental periods. The first marker to be detected was vimentin, which was initially found throughout the mesenchyme. During development vimentin became mostly restricted to the interductal tissue of the prostate and the lamina propria of the SV. Smooth muscle markers were expressed in an orderly sequence in a proximal to distal manner along prostatic ducts, from the urethra towards the tips. Expression of oc-actin was followed by vinculin, myosin, desmin, and laminin. These markers became localized to the developing smooth muscle sheaths and were not expressed in the interductal tissue of the prostate or the lamina propria of the SV. Organ culture experiments demonstrated that androgens were required for the differentiation of smooth muscle sheaths. Castration of adult rats demonstrated that androgens were required to maintain smooth muscle differentiation. In castrates, the stroma was relatively thicker but less dense than in intact animals. Following castration, expression of the smooth muscle markers was lost sequentially in the reverse order of their expression during development. In long-term castrates oc-actin, vimentin and a small amount of vinculin were detected. AR were first detected in the urogenital sinus mesenchyme immediately surrounding the epithelium at 16 days of gestation. As development progressed expression of AR became more widespread, and postnatally was found throughout the mesenchyme. As maturation of smooth muscle occurred, stromal expression of AR became localized to the muscular sheath immediately surrounding the epithelium. In the prostate the interductal connective tissue displayed very low levels of AR expression. In the SV, AR were also observed in the lamina propria. In summary, stromal differentiation and dedif-ferentiation in the rat prostate and SV were found to be androgen-dependent processes with ordered sequential ontogenic expression of specific markers.

Anti-factor D (AFD; FCFD4514S, lampalizumab) is a humanized IgG Fab fragment directed against factor D (fD), a rate-limiting serine protease in the alternative complement pathway (AP). Evaluation of AFD as a potential intravitreal (IVT) therapeutic for dry age-related macular degeneration patients with geographic atrophy (GA) is ongoing. However, it is unclear whether IVT administration of AFD can affect systemic AP activation and potentially compromise host-immune responses. We characterized the pharmacologic properties of AFD and assessed the effects of AFD administered IVT (2 or 20 mg) or intravenous (0.2, 2, or 20 mg) on systemic complement activity in cynomolgus monkeys. For the IVT groups, serum AP activity was reduced for the 20 mg dose group between 2 and 6 hours postinjection. For the intravenous groups, AFD inhibited systemic AP activity for periods of time ranging from 5 minutes (0.2 mg group) to 3 hours (20 mg group). Interestingly, the concentrations of total serum fD increased up to 10-fold relative to predose levels following administration of AFD. Furthermore, AFD was found to inhibit systemic AP activity only when the molar concentration of AFD exceeded that of fD. This occurred in cynomolgus monkeys at serum AFD levels $2 mg/ml, a concentration 8-fold greater than the maximum serum concentration observed following a single 10 mg IVT dose in a clinical investigation in patients with GA. Based on these findings, the low levels of serum AFD resulting from IVT administration of a clinically relevant dose are not expected to appreciably affect systemic AP activity.