Radioimmunotherapy targeting of HER2/neu oncoprotein on ovarian tumor using lead-212-DOTA-AE1

The specificity, toxicity and efficacy of lead (212Pb) radioimmunotherapy were evaluated in nude mice bearing the SK-OV-3 human ovarian tumor cell line expressing the HER2/neu proto-oncogene.

METHODS

The therapeutic agent used was the tumor-specific anti-HER2/neu monoclonal antibody AE1 conjugated to 212Pb, 212Bi being the daughter and thus the source of the alpha-particle and beta emissions. A bifunctional derivative of tetraazacyclododecanetetraacetic acid (p-SCN-Bz-DOTA) was used to couple 212Pb to the anti-HER2/neu monoclonal antibody AE1. The chelating agent did not alter the binding affinity to its antigenic target or the pharmacokinetics and tissue distribution of the AE1 antibody. Toxicity and therapeutic efficacy of 212Pb-AE1 were evaluated in nude mouse ascites or solid tumor models, wherein SK-OV-3 cells were administered i.p. or s.c., respectively.

RESULTS

The dose-limiting acute toxicity after i.v. administration of 212Pb-AE1 was bone marrow suppression, which was observed at doses above 25 microCi. Therefore, doses of 10 and 20 microCi were used in efficacy trials. The i.p. administration of 212Pb-AE1 3 days after i.p. tumor inoculation led to a significant (P2 = 0.015) prolongation of tumor-free survival. In a second model, i.v. treatment with 212Pb-AE1 3 days after s.c. tumor inoculation prevented subsequent tumor development in all animals treated with 10 or 20 microCi of 212Pb-AE1 (P2 = 0.002 compared to control groups). This efficacy in the adjuvant setting was antibody specific because treatments with equivalently labeled control antibody or unlabeled AE1 antibody or no treatment were less effective. The rate of growth of small (mean tumor volume, 15 mm3) SK-OV-3 tumors was modestly inhibited. However, tumor growth was not inhibited in mice bearing larger (mean tumor volume, 146 mm3) SK-OV-3 tumors by the administration of a single dose of 10 or 20 microCi of 212Pb-AE1.

CONCLUSION

Lead-212-AE1 as an intact radiolabeled monoclonal antibody may be of only modest value in the therapy of bulky solid tumors due to the short physical half-life of 212Pb and time required to achieve a useful tumor-to-normal tissue ratio of radionuclide after administration. However, the radiolabeled monoclonal antibody may be useful in therapy of tumors in the adjuvant setting. Furthermore, 212Pb may be of value in select situations, including treatment of leukemia, intercavitary therapy or strategies that target vascular endothelial cells of tumors.

[Pulmonary sling or ring-sling complex? respiratory problems--diagnosis, therapy, prognosis]

PS is a rare congenital vascular anomaly in which the left pulmonary artery originates from the right pulmonary artery and courses between trachea and esophagus to the hilus of the left lung causing compression of the right mainstem bronchus and trachea. In about half of all cases this vessel anomaly is associated with tracheo-bronchial and/or cardiovascular malformations. We present 6 patients with PS concentrating on the accompanying malformations of the tracheobronchial tree. All patients had the typical symptoms of wheezing and stridor already in early infancy. 3 patients showed concomitant tracheobronchial anomalies. 2 patients had additional cardiovascular deformities. In 3 of the patients the positive clinical course allowed conservative therapy. In the case of 2 further patients the respiratory problems demanded surgery, one of this patients died. A further patient died after palliative surgery of cardiac anomaly.

Compliance with therapy in children with respiratory diseases

Compliance with medical treatment was evaluated in 89 children and adolescents with respiratory diseases using two methods of assessment: a double blinded covert recording of the use of an air compressor for nebulization of drugs and the determination of theophylline levels in serum. In the covert monitoring of inhalation the overall compliance with the prescribed medication was 47.6%. In the open randomized theophylline trial, 56%-71% of the patients (according to uncontrolled or controlled intake of the drug) received a dosage of theophylline which was too low to achieve a sufficient serum level in the range of 10-20 mg/l. This, however, was also due to the fact that in 72% of the cases physicians prescribed doses which were substantially below the recommended amount of drug according to age and weight. It is, therefore, concluded that compliance of medication is based on the patients adherence to the medication, to the efficacy of the drug itself and the attitude of the physician.

Determinants of trimetrexate lethality in human colon cancer cells

We examined the cytotoxicity and biochemical effects of the lipophilic antifol trimetrexate (TMQ) in two human colon carcinoma cell lines, SNU-C4 and NCI-H630, with different inherent sensitivity to TMQ. While a 24 h exposure to 0.1 microM TMQ inhibited cell growth by 50-60% in both cell lines, it did not reduce clonogenic survival. A 24 h exposure to 1 and 10 microM TMQ produced 42% and 50% lethality in C4 cells, but did not affect H630 cells. Dihydrofolate reductase (DHFR) and thymidylate synthase were quantitatively and qualitatively similar in both lines. During drug exposure, DHFR catalytic activity was inhibited by > or = 85% in both cell lines; in addition, the reduction in apparent free DHFR binding capacity (< or = 20% of control), depletion of dTTP, ATP and GTP pools and inhibition of [6-3H]deoxyuridine incorporation into DNA were similar in C4 and H630 cells. TMQ produced a more striking alteration of the pH step alkaline elution profile of newly synthesised DNA in C4 cells compared with 630 cells, however, indicating greater interference with DNA chain elongation or more extensive DNA damage. When TMQ was removed after a 24 h exposure to 0.1 microM, recovery of DHFR catalytic activity and apparent free DHFR binding sites was evident over the next 24-48 h in both cell lines. With 1 and 10 microM, however, persistent inhibition of DHFR was evident in C4 cells, whereas DHFR recovered in H630 cells. These data suggest that, although DHFR inhibition during TMQ exposure produced growth inhibition, DHFR catalytic activity 48 h after drug removal was a more accurate predictor of lethality in these two cell lines. Several factors appeared to influence the duration of DHFR inhibition after drug removal, including initial TMQ concentration, declining cytosolic TMQ levels after drug removal, the ability to acutely increase total DHFR content and the extent of TMQ-mediated DNA damage. The greater sensitivity of C4 cells to TMQ-associated lethality may be attributed to the greater extent of TMQ-mediated DNA damage and more prolonged duration of DHFR inhibition after drug exposure.

Amphiregulin, epidermal growth factor receptor, and estrogen receptor expression in human primary breast cancer

Amphiregulin is a recently described member of the epidermal growth factor family. Primary breast cancers were assessed for expression of amphiregulin by immunochemistry (111 cases), Northern, and/or dot blots (68 cases). Epidermal growth factor and estrogen receptors were measured in all cases. p53 and erbB-2 expression was assessed by immunohistochemistry for most cases. There was no association of these factors with amphiregulin expression, which was detected by immunochemistry in 40 of 111 cases. A significant association of amphiregulin expression assessed by Northern dot blots versus immunochemical staining was seen (P = 0.0016). Expression was not detected in adjacent nontumor tissue by immunochemistry. Amphiregulin was expressed in tumor epithelium, but not stromal or inflammatory cells. Expression was more common in lymph node positive cases (23 of 49; 47%) than lymph node negative cases (11 of 42; 26%; P = 0.04). The coexpression of epidermal growth factor receptor and amphiregulin in 35% of epidermal growth factor receptor positive cases raises the possibility of an autocrine loop in this subset of patients. Amphiregulin stimulates fibroblast growth and is up-regulated in breast cancer. A possible effect on tumor stroma may relate to the association with metastases.

Measuring proliferation in routine fine needle aspirates. Immunocytochemical detection of bromodeoxyuridine incorporation and Ki-67 expression in breast aspirates

Two simple quantitative means of measuring tumour proliferation which can be applied to cytological material are described. One method involves immunocytochemical staining of cytological smears prepared from breast aspirates with the monoclonal antibody Ki-67. The other method involves incubation of aspirated material with 5-Bromo-2-deoxyuridine (BrdU). Direct measurement of the S phase of the cell cycle is feasible in breast fine needle aspirates by Bromodeoxyuridine incorporation and subsequent immunocytochemical detection. The proliferation indices obtained correlate with those derived from Ki-67 staining. This technique is suitable for routine use in the assessment of tumour proliferation.

OK. Phaeogalera and Galerina in arctic-subarctic Alaska (U.S.A.) and the Yukon Territory (Canada)

Eleven taxa of Galerina and Phaeogalera are described. Galerina leptocystis, Galerina subarctica, and Galerina praticola are reported from arctic North America for the first time. Phaeogalra stagnina is only found in very humid, wet meadow tundra associated with Drepanocladus or Calliergon. Galerina arctica is reported for the first time from Alaska and Canada. One species, Galerina pseudocerina, is found only in arctic alpine habitats in Canada and not in the arctic tundra. Two forms of Galerina pseudomycenopsis represent the most common taxon observed in Alaskan North Slope wet meadow tundra on peat or associated with Calliergon, Drepanocladus, and Sphagnum. Two species, Galerina clavata and Galerina hypnorum, are common cosmopolitan taxa, but only G. clavata is frequently encountered on the Alaskan North Slope. The association of the Galerina taxa with mosses is presented and discussed, as well as their occurrence in microhabitats in wet meadow tundra and among polygons in coastal tundra on the Alaskan North Slope. Key words: Galerina, Phaeogalera, Cortinariaceae, Alaska, Yukon Territory, bryophytes.

Mutant p53, EGF receptor and c-erbB-2 expression in human breast cancer

p53 expression was studied in 111 primary breast cancers with a monoclonal antibody (PAb240) that reacts with an epitope in mutant p53. Epidermal growth factor receptors (EGFr) and oestrogen receptors (ER) measured by ligand binding, c-erbB-2 expression assessed by immunochemistry and lymph node status were compared with p53 staining. Fifty-nine tumours (53%) were positive for p53, and this correlated with EGFr expression (P less than 0.02), which is a known poor prognostic factor. Eighteen out of 59 p53+ tumours expressed c-erbB-2 versus 4 out of 52 p53- tumours assessed on paraffin sections. However, assessing c-erbB-2 by Southern blotting and immunochemistry on frozen sections showed that 20 out of 59 p53+ tumours overexpressed or had amplified c-erbB-2 compared with 15 out of 52 p53- tumours (not significant). Mean EGFr concentration in p53+ tumours was 31 fmol per mg of membrane protein versus 14 fmol mg-1 in p53- tumours. Cytoplasmic staining was the most frequent pattern found for p53, but some cases showed cytoplasmic plus nuclear staining, or focal cells with predominantly nuclear staining. Thus, abnormal p53 is the commonest oncogene abnormality described in breast cancer. The association with EGFr expression suggests that these oncogenes interact in the pathogenesis of breast cancer.

Human tumour-associated NK cells secrete increased amounts of interferon-gamma and interleukin-4

Numerous interactions between malignant and stromal/inflammatory cells take place within solid human tumours, which are mediated, in part, by the release of signalling proteins called cytokines. In the present study, we have compared the secretion of two important immunomodulatory cytokines, IFN-gamma and IL-4 by individual, immunophenotyped NK cells freshly isolated from either malignant tumour biopsies, or peripheral blood samples from patients with ductal invasive breast cancer. Due to the marked heterogeneity amongst cells isolated from these clinical samples, we have employed a technique called the reverse haemolytic plaque assay to identify and enumerate cytokine-secreting cells at the single cell level. Our data indicate that NK cells isolated directly from the tumour site secrete more IFN-gamma and IL-4 than NK cells from the blood of the same patients. However, a greater proportion of CD16+ cells from both sources in breast cancer patients secreted IFN-gamma than of those from the blood of healthy donors. We also show that factors secreted by the human breast cell lines, MCF-7 and MDA-231 PN9, were able to mimic the stimulatory influence of the tumour microenvironment on secretory activity of NK cells.

Effect of calcium/phosphorus ratio on mineral retention in parenterally fed premature infants

We hypothesized that retention of parenterally delivered calcium (Ca) and phosphorus (P) is affected by the ratio of the delivered minerals and that a 1.7:1 ratio would be optimal since this is the ratio of retention of these minerals by the fetus. Forty-one very low birth weight (VLBW) infants were randomly assigned to one of three total parenteral nutrition (TPN) solutions that were different only in their Ca:P ratios: 2:1 (76 mg/kg/day Ca and 38 mg/kg/day of P), and 1.3:1 (58 mg/kg/day Ca and 45 mg/kg/day P), and 1.3:1 (58 mg/kg/day of Ca and 45 mg/kg/day of P). Serum levels of calcium, phosphorus, and alkaline phosphatase, retentions of calcium and phosphorus and urinary cyclic AMP levels were measured after 48 h on the assigned Ca to P ratio. Calcium retentions were higher with the 2:1 and 1.7:1 ratios and phosphorus retentions were higher with the 1.3:1 and 1.7:1 ratios. The 1.7:1 ratio allowed for the highest absolute retention of both minerals and was the closest to published in utero accretion of calcium and phosphorus. The serum and urine studies demonstrated no abnormalities on any of the three ratios. Cyclic AMPs were not different among groups and were not elevated compared to previous reports suggesting that none resulted in parathyroid hormone (PTH) stimulation. We conclude that the 1.7:1 ratio is better than higher or lower ratios for delivery of calcium and phosphorus in TPN solutions at the quantities studied.

Measurement of cytokine release by human cells. A quantitative analysis at the single cell level using the reverse haemolytic plaque assay

The reverse haemolytic plaque assay has been adapted to detect and measure the release of such cytokines as interleukin-1, -2 and -6, GM colony-stimulating factor or interferon-gamma by individual human cells derived from either peripheral blood or enzymatically dispersed breast carcinomas. Since each of these peptides is released by more than one cell type, this in vitro assay has been coupled with immunocytochemistry to identify the particular cell type(s) contributing to the release of each cytokine. This technique is useful in (i) obviating the need for purification of a given cell type prior to estimating cytokine release, and (ii) evaluating quantitative differences in secretion amongst cells of a particular type. Such a method has the additional advantage over most alternative methods applied at the single cell level in that the cells remain viable at the end of the assay and can be used in further studies. This assay thus provides a powerful new tool in the investigation of the role of cytokines in both the normal modulation of the immune system and the development of such diseases as neoplasia.