A phase II trial of murine monoclonal antibody 17-1A and interferon-γ: Clinical and immunological data

Summary A group of 15 patients with metastatic colorectal adenocarcinoma received a combination of interferon (0.1 mg/m², days 1–15) and the murine monoclonal antibody 17-1A (400 mg, days 5, 7, 9 and 12). The treatment was tolerated with minimal toxicity. Of the 14 evaluable patients, 13 developed human antibody to murine 17-1A, with 11 patients demonstrating antibody to the variable region of 17-1A (anti-idiotype). Antibody to the variable region was inhibited by 17-1A but not by mouse immunoglobulin. Sera from patients with substantial anti-idiotype reactivity were capable of inhibiting the binding of murine 17-1A to antigen expressing LS174-T cells thus indicating the presence of antibody directed against the 17-1A combining site (mirror-image anti-idiotype). The median survival of the whole group was 56 weeks and there was no correlation between clinical response/survival and the development of anti-idiotype antibody.Supported by the Veterans Administration Medical Center and by Public Health Services grant CA 45 232 from the National Cancer Institute, National Institutes of Health, Department of Health and Human Services     

Alterations in hexose monophosphate shunt during lymphoblastic transformation

This study characterized the alteration in hexose monophosphate shunt (HMPS) activity occurring during lymphoblastic transformation to nonspecific mitogens. Average HMPS activity was threefold higher in phytohemagglutinin (PHA)-stimulated cultures incubated for 68 hr when compared to unstimulated cultures. Serial measurement of HMPS activity indicated that this increased activity was delayed for several hours after the addition of the mitogen and reached a peak of fivefold higher activity during the second day of culture. Glycolysis increased before HMPS activity and was increased during the entire culture period although it was also maximal during the second day of culture. Pokeweed mitogen also resulted in increased glucose metabolism. The increase was of lesser magnitude than PHA and probably reflected the lower degree of lymphoblastic transformation of pokeweed cultures.These studies demonstrate that lymphocytes undergoing blastic transformation have increased HMPS activity which follows a predictable temporal pattern as does glucose consumption. Also, this study demonstrates that the ionization chamber electrometer technique for the direct measurement of ¹⁴CO₂ can be applied to the study of long-term tissue cultures.     

<Emphasis Type="Italic">mab-31</Emphasis> and the TGF-β pathway act in the ray lineage to pattern <Emphasis Type="Italic">C. elegans</Emphasis>male sensory rays

Background  

C. elegans TGF-β-like Sma/Mab signaling pathway regulates both body size and sensory ray patterning. Most of the components in this pathway were initially identified by genetic screens based on the small body phenotype, and many of these mutants display sensory ray patterning defect. At the cellular level, little is known about how and where these components work although ray structural cell has been implicated as one of the targets. Based on the specific ray patterning abnormality, we aim to identify by RNAi approach additional components that function specifically in the ray lineage to elucidate the regulatory role of TGF-β signaling in ray differentiation.     

Interaction of monocytes with tumor cells coated with complement with or without antibody

Raji, a human B lymphoblastoid cell line has the ability to activate the complement cascade by alternate pathway mechanisms with subsequent fixation of C3 to receptors on the Raji cell membrane. Using this property, we examined the role that complement plays in mediating a cytolytic event between human peripheral blood monocytes and Raji cells coated with C3b, antibody, or both. Presence of C3 was confirmed by immune adherence. IgG bound to the Raji membrane was quantitated using I¹²⁵ Staphylococcal protein A assay. The presence of alternate pathway-activated C3 on Raji cells failed to produce monocyte-mediated cytotoxicity. These same target cells subsequently coated with antibody concentration ranging from 200 to >600,000 SPA molecules per Raji cell produced neither enhancement nor inhibition of antibody-dependent, cell-mediated cytotoxicity (ADCC). ADCC was enhanced by complement when complement activation and binding of C3 to the cell surface occurred by classical pathway mechanisms. ADCC of 32% ± 3.2 occurred with undiluted antiserum (625,000 SPA molecules bound/Raji cell) with enhancement to 52% ± 1.1 in the presence of C3. IgG inhibition of ADCC was unaffected by the presence of membrane-bound C3.     

The small heat shock protein alpha B-crystallin is a novel inhibitor of TRAIL-induced apoptosis that suppresses the activation of caspase-3

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor alpha family of cytokines that preferentially induces apoptosis in transformed cells, making it a promising cancer therapy. However, many neoplasms are resistant to TRAIL-induced apoptosis by mechanisms that are poorly understood. We demonstrate that the expression of the small heat shock protein alpha B-crystallin (but not other heat shock proteins or apoptosis-regulating proteins) correlates with TRAIL resistance in a panel of human cancer cell lines. Stable expression of wild-type alpha B-crystallin, but not a pseudophosphorylation mutant impaired in its assembly and chaperone function, protects cancer cells from TRAIL-induced caspase-3 activation and apoptosis in vitro. Furthermore, selective inhibition of alpha B-crystallin expression by RNA interference sensitizes cancer cells to TRAIL. In addition, wild-type alpha B-crystallin promotes xenograft tumor growth and inhibits TRAIL-induced apoptosis in vivo in nude mice, whereas a pseudophosphorylation alpha B-crystallin mutant impaired in its anti-apoptotic function inhibits xenograft tumor growth. Collectively, these findings indicate that alpha B-crystallin is a novel regulator of TRAIL-induced apoptosis and tumor growth. Moreover, these results demonstrate that targeted inhibition of alpha B-crystallin promotes TRAIL-induced apoptosis, thereby suggesting a novel strategy to overcome TRAIL resistance in cancer.     

Identification of hypoxanthine as the major compoenet of a chromatographic fraction of transfer factor.

A chromatographic fraction of transfer factor capable of transferring delayed hypersensitivity has been shown by us and recently confirmed by others to elute from a Sephadex G-25 column in a peak after the total column volume. The chemical composition of this fraction (TFc) was determined using fractions prepared in the same manner as preparations previously shown to have biologic activity. The major component in this fraction has been identified as hypoxanthine by identical behavior in paper, ion exchange, and gel permeation chromatography systems as well as by comparison of ultraviolet (uv), nuclear magnetic resonance (NMR) and infrared (IR) spectra of the column purified material with the spectra of crystalline hypoxanthine. In addition, the uv absorption of TFc can be converted quantitatively to uric acid by incubation with xanthine oxidase. Possible explanations for this observation include: 1) the material responsible for transfer of delayed hypersensitivity may be degraded and absent from these preparations, 2) the antigen specific component may constitute a very minor component of this fraction while hypoxanthine is responsible for some of the reported non-specific effects of transfer factor, and 3) the antigen specific transfer factor material does not elute in this fraction.