Targeting HER2/neu with a fully human IgE to harness the allergic reaction against cancer cells

Breast and ovarian cancer are two of the leading causes of cancer deaths among women in the United States. Overexpression of the HER2/neu oncoprotein has been reported in patients affected with breast and ovarian cancers, and is associated with poor prognosis. To develop a novel targeted therapy for HER2/neu expressing tumors, we have constructed a fully human IgE with the variable regions of the scFv C6MH3-B1 specific for HER2/neu. This antibody was expressed in murine myeloma cells and was properly assembled and secreted. The Fc region of this antibody triggers in vitro degranulation of rat basophilic cells expressing human FcεRI (RBL SX-38) in the presence of murine mammary carcinoma cells that express human HER2/neu (D2F2/E2), but not the shed (soluble) antigen (ECDHER2) alone. This IgE is also capable of inducing passive cutaneous anaphylaxis in a human FcεRIα transgenic mouse model, in the presence of a cross-linking antibody, but not in the presence of soluble ECDHER2. Additionally, IgE enhances antigen presentation in human dendritic cells and facilitates cross-priming, suggesting that the antibody is able to stimulate a secondary T-cell anti-tumor response. Furthermore, we show that this IgE significantly prolongs survival of human FcεRIα transgenic mice bearing D2F2/E2 tumors. We also report that the anti-HER2/neu IgE is well tolerated in a preliminary study conducted in Macaca fascicularis (cynomolgus) monkeys. In summary, our results suggest that this IgE should be further explored as a potential therapeutic against HER2/neu overexpressing tumors, such as breast and ovarian cancers.Fil: Daniels, Tracy R.. University of California at Los Angeles; Estados UnidosFil: Leuchter, Richard K.. University of California at Los Angeles; Estados UnidosFil: Quintero, Rafaela. University of California; Estados UnidosFil: Helguera, Gustavo Fernando. University of California at Los Angeles; Estados Unidos. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodríguez, José A.. University of California at Los Angeles; Estados UnidosFil: Martínez Maza, Otoniel. University of California at Los Angeles; Estados UnidosFil: Schultes, Birgit C.. Advanced Immune Therapeutics, Inc.; Estados Unidos. Momenta Pharmaceuticals, Inc.; Estados UnidosFil: Nicodemus, Christopher F.. Advanced Immune Therapeutics, Inc.; Estados UnidosFil: Penichet, Manuel L.. University of California at Los Angeles; Estados Unido

A novel IgE antibody targeting the prostate-specific antigen as a potential prostate cancer therapy

Prostate cancer (PCa) is the second leading cause of cancer deaths in men in the United States. The prostate-specific antigen (PSA), often found at high levels in the serum of PCa patients, has been used as a marker for PCa detection and as a target of immunotherapy. The murine IgG1 monoclonal antibody AR47.47, specific for human PSA, has been shown to enhance antigen presentation by human dendritic cells and induce both CD4 andCD8 T-cell activation when complexed with PSA. In this study, we explored the properties of a novel mouse/human chimeric anti-PSA IgE containing the variable regions of AR47.47 as a potential therapy for PCa. Our goal was to take advantage of the unique properties of IgE in order to trigger immune activation against PCa.Fil: Daniels-Wells, Tracy R. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América;Fil: Helguera, Gustavo Fernando. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Tecnologia Farmaceutica; Argentina; University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América;Fil: Leuchter, Richard K. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América;Fil: Quintero, Rafael. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América;Fil: Kozman, Maggie. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América;Fil: Rodríguez, José A.. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América; University of California. The Molecular Biology Institute; Estados Unidos de América;Fil: Ortiz-Sánchez, E. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América; Biomedical Research in Cancer. Basic Research Division. National Institute of Cancerology; Mexico.;Fil: Martínez-Maza, Otonel. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América;Fil: Schultes, Brigit C.. Advanced Immune Therapeutics; Estados Unidos de América;Fil: Nicodemus Christopher. Advanced Immune Therapeutics; Estados Unidos de América;Fil: Penichet, Manuel. University of California. David Geffen School of Medicine. Department of Surgery. Division of Surgical Oncology; Estados Unidos de América; University of California. The Molecular Biology Institute; Estados Unidos de América

The use of the electrolyte leakage method for assessing cell membrane stability as a water stress tolerance test in durum wheat

This work was carried out to adapt the electrolyte leakage technique to durum wheat and then to evaluate its relevance in the assessment of the cell membrane stability as a mechanism of water stress tolerance in this species. The method currently used is based on in vitro desiccation of leaf tissues by a solution of polyethylene glycol (PEG) and a subsequent measurement of electrolyte leakage into deionised water. It consists of three successive steps: (1) a washing treatment to remove solutes from both leaf surfaces and cells damaged by cutting; (2) a stress period during which the leaf tissues are plunged in a PEG-solution and (3) a rehydration period during which after-effects of the stress are evaluated. During the washing period, the major part of electrolytes was removed within 15 min. Varying the stress conditions influenced both the percent and the kinetics of electrolyte leakage during rehydration. Electrolyte leakage exhibited a characteristic pattern reflecting the condition of cellular membranes (repair and hardening). In practice, we recommend a 15-minute washing time, a 10-hour stress period and 4 h of rehydration. The extent of the cell membrane damage not only correlated well with the growth responses of wheat seedlings belonging to various cultivars to withholding water but also with the recognised field performances of these cultivars. The relative proportion of endogenous ions lost in the effusate during the rehydration step may vary strongly according to the element analysed and the precise nutritional status of the plant should therefore be considered. However, an increase in inorganic ion leakage does not fully explain the recorded PEG-induced increase in electrical conductivity (EC) during the subsequent rehydration step and organic ions are probably also involved in such an increase

Effects of duration and intensity of aluminum stress on growth parameters in four rice genotypes differing in aluminum sensitivity

The effects of aluminum (Al) stresses of varying intensities and durations on growth parameters were investigated in four Oryza sativa L. genotypes (two Al sensitive, two Al resistant). Our results support the current opinion that the use of only one parameter cannot easily account for differences in Al resistance, since Al concentration or stress duration can affect plant responses in opposite directions. For short stress duration (40 days) at Al 500 mu M, weight parameters appear to be more discerning than length parameters. Necrosis evaluation is a more reliable criterion for plants maintained for a long time (80 days) in the presence of high Al concentrations (Al 1000 or 1500 mu M)

Improvement of rice callus regeneration in the presence of NaCl

The effects of abscisic acid (37.8 mu M), polyethylene glycol (5%), proline (10 mM), tryptophan (490 mu M) and indoleacetic acid (5.7 mu M) on rice callus regeneration were studied at various doses of NaCl (0, 50 and 100 mM) on three month-old mature embryo-derived callus of two japonica (I Kong Pao and Aiwu) and two indica (IR 2153 and Nona Bokra) rice cultivars differing in salinity tolerance. NaCl strongly decreased the regeneration frequency of all cultivars but slightly increased the survival of regenerated plantlets. Tryptophan stimulated regeneration and increased subsequent survival rates of regenerated plantlets in all cultivars at all NaCl doses. Abscisic acid and polyethylene glycol, though not affecting the final regeneration percentages, delayed regeneration and reduced the mean number of plantlets produced per regenerating callus in all cultivars, as well as rooting ability and survival of regenerated plantlets in indica genotypes. Proline had no marked effect on regeneration, whatever the NaCl dose or cultivar, while indoleacetic acid reduced shoot regeneration and increased root regeneration

NaCl impact on somaclonal variation exhibited by tissue culture-derived fertile plants of rice (Oryza sativa L.)

In order to analyse the effects of NaCl added to in vitro culture media on subsequent somaclonal variation exhibited by regenerated plants (R-0) and their R-1 and R-2 progenies, four procedures of in vitro selection differing in the stage of stress imposition were applied to mature embryo-derived calli obtained from three rice cultivars. Somaclonal variation was quantified at maturity for seven yield-related parameters on fertile plants cultivated in the absence of-salt. For most parameters, R-0, R-1 and R-2 plants performed less than the initial cultivar but their variability also strongly increased and maximal values were often recorded on tissue culture-derived plants. Somaclonal variation depended on genotype, morphological parameter analysed, NaCl dose and stage of stress imposition. Exposure to NaCl during proliferation phase decreased the extent of somaclonal variation in R-0 comparatively to plane regenerated from non-stressed calli, but it was still higher than somaclonal variation observed when NaCl was added to regeneration medium. Subsequent evolution of somaclonal variation in R-1 and R-2 populations suggested that NaCl added to proliferation medium mainly restricted the physiological component of somaclonal variation while such a trend was not observed when NaCl was added to regeneration or rooting media

Compared effects of sudden and progressive impositions of salt stress in three durum wheat (Triticum durum Desf.) cultivars

The effect of sudden vs. progressive exposure to salt stress at the seedling stage was investigated in three durum wheat cultivars differing in their mean level of sale and drought resistance. Both procedures of stress imposition induced a decrease in relative growth rates, K concentrations and leaf osmotic potential values, as well as an increase in Na, proline and soluble sugar contents. Growth inhibition was largest in the drought-resistant cultivar Omrabi 5, suggesting that drought and salt-resistance are not necessarily linked in Triticum durum. Suddenly-applied NaCl often appeared more detrimental than progressive exposure. Quantitative differences between the effects of the two modes of stress imposition suggested the existence of a precocious adaptative mechanism in response to progressive exposure but varied according to the physiological parameter used to evaluate plant behaviour, the final dose of NaCl and the genotype. The most salt-resistant cultivar (Belikh) was the less influenced by the kinetics of stress application. The modification of the mineral nutrition- and osmotic adjustment-related parameters is discussed in relation to the specific physiological strategy of salinity resistance postulated in Triticum durum and in light of the contrasting evidence in the literature

Heritable chilling tolerance improvement in rice through somaclonal variation and cell line selection

Embryo-derived calli of four rice varieties (Oryza sativa L.) were submitted to different continuous or discontinuous periods of chilling stress at 4 degrees C, with a total length varying from 2 to 6 weeks. Other calli were cultivated during different times without cold stress. The reduction of plant regeneration percentages induced by low temperature was more pronounced in the more cold-sensitive varieties. Regenerated plants (RO) and their descendants in R1, R2 and R3 generations were cold-screened together with control plants. A mass selection was applied to the control plants during three successive generations. In all varieties, significantly higher chilling survival rates were obtained in R3 with in vitro grown plants than with control plants. Higher plant survival rates were obtained with the more chilling-sensitive varieties when a short discontinuous chilling treatment or no treatment had been applied, with the intermediate variety with short or intermediate treatments, and with the more cold-tolerant variety with longer, continuous treatments. The relative importance of pre-existing versus in vitro-induced variation and of epigenetic versus heritable variation, along with the significance of such cold tolerance improvement for breeding purposes are discussed