05-166 Sigma-AldrichAnti-IGF-II Antibody, clone S1F2

This study was to test the hypothesis that altered IGF2 system in the placental labyrinth zone (LZ) impairs feto-placental growth in response to maternal protein restriction. Rats were fed a 20% protein diet and an isocaloric 6 % protein diet (LP) from day 1 to days 14, 18, or 21 of pregnancy. The effects of diet, gender of placenta and fetus, and day of pregnancy on placental weight, fetal weight, and expression of the IGF2 axis in the placental LZ and amino acids in maternal plasma were analyzed. Growth restriction occurred in both female and male fetuses by LP, coincident with impaired LZ growth and efficiency. The expression of Igf2, Igf2P0, Igf1r, Igf2r, Insr, Igfbp1, and Igfbp2 in placental LZ were affected by diet, gender and/or day of pregnancy. Concentrations of total essential amino acids and total nonessential amino acids were reduced and increased, respectively, in maternal plasma of LP-fed rats. These results indicate that adaptation of the IGF2 system in rat LZ occurs in a sex- and time-dependent manner in response to maternal protein restriction; however, these adaptations cannot prevent the growth restriction of both male and female fetuses during late pregnancy.

This study aimed to identify molecular determinants of sensitivity of non-small cell lung cancer (NSCLC) to anti-insulin-like growth factor receptor (IGF-IR) therapy.A total of 216 tumor samples were investigated, of which 165 consisted of retrospective analyses of banked tissue and an additional 51 were from patients enrolled in a phase II study of figitumumab, a monoclonal antibody against IGF-IR, in stage IIIb/IV NSCLC. Biomarkers assessed included IGF-IR, epidermal growth factor receptor, IGF-II, IGF-IIR, insulin receptor substrate 1 (IRS-1), IRS-2, vimentin, and E-cadherin. Subcellular localization of IRS-1 and phosphorylation levels of mitogen-activated protein kinase and Akt1 were also analyzed.IGF-IR was differentially expressed across histologic subtypes (P = 0.04), with highest levels observed in squamous cell tumors. Elevated IGF-IR expression was also observed in a small number of squamous cell tumors responding to chemotherapy combined with figitumumab (P = 0.008). Because no other biomarker/response interaction was observed using classical histologic subtyping, a molecular approach was undertaken to segment NSCLC into mechanism-based subpopulations. Principal component analysis and unsupervised Bayesian clustering identified three NSCLC subsets that resembled the steps of the epithelial to mesenchymal transition: E-cadherin high/IRS-1 low (epithelial-like), E-cadherin intermediate/IRS-1 high (transitional), and E-cadherin low/IRS-1 low (mesenchymal-like). Several markers of the IGF-IR pathway were overexpressed in the transitional subset. Furthermore, a higher response rate to the combination of chemotherapy and figitumumab was observed in transitional tumors (71%) compared with those in the mesenchymal-like subset (32%; P = 0.03). Only one epithelial-like tumor was identified in the phase II study, suggesting that advanced NSCLC has undergone significant dedifferentiation at diagnosis.NSCLC comprises molecular subsets with differential sensitivity to IGF-IR inhibition.

It has been previously shown that adrenocortical tumors (ACT) in adults exhibit structural abnormalities in tumor DNA in approximately 30% of cases. These abnormalities involve chromosome 11p15 and include loss of heterozygosity, paternal isodisomy, and overexpression of the gene for insulin-like growth factor II (IGF2), correlating with DNA demethylation at this locus. It has been hypothesized that these events occur late in the tumorigenic process in adults and seem to correlate with a worse prognosis. We present 4 pediatric cases of ACT diagnosed at 2.5 yr, 10 months, 12 yr, and 2.2 yr. All 4 patients presented with virilization, and 1 patient also showed signs and symptoms of glucocorticoid excess. The youngest patient's maternal aunt had surgical excision of a more than 15-cm ACT 18 yr previously, but the aunt is doing well at age 23 yr. They all had surgical removal of their tumors. The 2.5-yr-old child also received chemotherapy and radiotherapy because of capsular rupture and, after 3 local recurrences, died 3.3 yr after initial presentation. We investigated all 4 tumors for chromosome 11 structural abnormalities (11p15.5 to 11q23), IGF2 and H19 expression by competitive RT-PCR analysis, and IGF2 methylation patterns by Southern analysis. All 4 tumors (100%) showed a combination of structural abnormalities at the 11p15 locus with mosaic loss of heterozygosity involving 11p. All tumors also had significantly increased IGF2 messenger ribonucleic acid levels relative to normal adrenal (up to 36-fold) and significant IGF2 demethylation (mean, 87%). H19 messenger ribonucleic acid levels were undetectable in 3 of 4 tumors, explained in part by mosaic loss of the actively expressed maternal allele for this imprinted gene. By immunohistochemistry we were able to confirm increased IGF-II peptide levels within the tumor tissue in 10 pediatric patients, including the 4 patients described above. Concomitantly, we also observed nuclear accumulation of p53, suggesting somatic mutations. For the 10-month-old patient, sequencing revealed a p53 germline mutation. We therefore conclude that in pediatric ACT, structural abnormalities of tumor DNA and IGF2 overexpression as well as p53 mutations are very common and are therefore less useful for prognosis than in adults. Our findings support the theory that pediatric ACT, whose IGF2 expression and steroidogenesis evoke the phenotype of the fetal adrenal cortex, may arise because of defective apoptosis.

Basement membrane promotes the reassembly of isolated type II alveolar cells into alveoli-like structures, a process attributable in part to a novel cell adhesion site in the alpha 1-chain of laminin-1 (M. L. Matter and G. W. Laurie. J. Cell Biol. 124: 1083-1090, 1994). The possibility that basement membrane contains other alveolarization activities was probed by subtraction analysis and use of neutralizing antibodies. Deletion of components 100 kDa, and subsequently 10 kDa, reduced alveolar cross-sectional area by 70% to 22-25 x 10(3) microns2: the approximate size of alveolar-like structures formed on purified laminin-1 alone. The deleted basement membrane material was adhesive for type II alveolar cells but failed to support alveolar formation in the absence of laminin-1. Preincubation of basement membrane with neutralizing anti-epidermal growth factor (EGF), -basic fibroblast growth factor (bFGF), -insulin-like growth factor (IGF)II, or -transforming growth factor (TGF)-beta antibodies had no inhibitory effect. Because both subtracted basement membrane preparations have in common the exclusion of components 10 kDa, these results are interpreted as pointing to a sub-10-kDa alveolarization activity(s) that plays a key accessory role in laminin-1-dependent alveolar formation.

In vitro exposure to low-energy, combined magnetic fields (CMF) increased the release of insulin-like growth factor (IGF)-II from human TE-85 osteosarcoma cells. Short-term CMF exposure of only 10 min increased IGF-II levels in conditioned medium 1 h post CMF exposure. IGF-II levels were measured with a radioreceptor assay using H-35 cells that contain abundant IGF-II but not IGF-I receptors. This assay also uses a recently validated BioGel P-10 acid gel filtration method to remove IGF binding protein before quantitation of either IGF-I or IGF-II. In addition to an increase in IGF-II levels, DNA synthesis, as an index of cell proliferation, was increased during the 24-h period post CMF exposure. A monoclonal antibody against IGF-II blocked the increase in cell proliferation following CMF exposure, whereas a control monoclonal antibody against osteocalcin did not attenuate the mitogenic action of CMF exposure. The effect of CMF exposure to increase both cell proliferation and IGF-II was cell-density dependent with greater stimulation by CMF observed at lower densities. Together, these data are consistent with the hypothesis that CMF exposure stimulates release/production of IGF-II from bone cells and that increased IGF-II then promotes an increase in cell proliferation.