Search PubMed⌕ Search

Biomedical subjects

K S Webb

Publications and source records attributed to K S Webb.

13 recordsLinked to original sources
PubMed1991

Establishment and characterization of a new human prostatic carcinoma cell line (DuPro-1).

A new human prostate adenocarcinoma cell line (DuPro-1) has been established from the athymic nude mouse supported xenograft DU5683. This was accomplished by embedding dispersed xenograft cells in 0.1 by 5.0 cm. spaghetti-like strands of Basement Membrane MATRIGEL [BMM (Collaborative Research, Inc.)], a unique technique facilitating the transition to tissue culture. Now passed over 30 times, the cells display anchorage and serum concentration independent growth with a doubling time of 22 to 24 hours. Cells exhibit pronounced morphological differences when grown on BMM coated culture dishes, assuming a pseudoglandular configuration, in contrast to typical homogeneous monolayer growth on plastic culture dishes. Light and electron microscopy show cohesive sheets of anaplastic epithelial cells, consistent with prostate carcinoma. Karyotypic analysis revealed all human chromosomes, near tetraploidy, 10 to 12 markers, and 3 to 4 X chromosomes, without a Y chromosome. Cells injected s.c. or embedded in BMM and implanted in the subrenal capsule space are equally tumorigenic in male and female athymic mice, suggesting that DuPro-1 cells are hormonally insensitive. Embedding cells in BMM may be useful in developing other tissue culture cell lines from neoplasms difficult to initiate in vitro. DuPro-1 should provide a valuable means to study the biology, immunology, and chemosensitivity of human prostate cancer.

Adenocarcinoma↗
PubMed1990

Characterization of a new model of human prostatic cancer: the multicellular tumor spheroid.

Multicellular tumor spheroids (MTS) provide a closer in vitro correlate to in vivo malignancy than do conventional monolayer cultures; while simulating many parameters of in vivo growth, MTS systems provide those perquisites (i.e., experimental control, economy, expediency) associated with in vitro evaluation of preclinical therapeutic strategies. For these reasons, we exploited the proclivity of the highly metastatic human prostatic carcinoma subline I-LN-PC3-IA to spontaneously assume a spheroid morphology under routine culture conditions. I-LN spheroids demonstrate salient features described in other spheroid systems and exhibit histologic characteristics of human prostate carcinoma. Cells encompassed in the I-LN spheroid format demonstrated functional divergence from their monolayer counterparts with respect to immunoreactivity for prostatic acid phosphatase, positional dependence of prostate-restricted p40 antigen expression, and chemotherapeutic drug response. This new in vitro-in vivo transition model of human prostatic carcinoma should provide a valuable in vitro context to expediently evaluate in vivo correlates of oncolytic protocols on a malignancy that remains refractive to therapy.

Antineoplastic Agents↗
PubMed1986

Metastatic phenotype of human prostate tumor cells in athymic nude mice: alteration by exposure to ethyl methanesulfonate and "reversion" by 5-azacytidine.

The human prostate tumor subline 1-LN-PC-3-1A (1-LN) is reproducibly metastatic in adult athymic nude mice. Cells surviving a brief in vitro exposure to ethyl methanesulfonate (EMS) exhibited a profound decrease in capacity for experimental lung metastasis in nude mice. Thirty days after EMS treatment, 1 X 10(6) uncloned EMS-treated 1-LN cells (1-LN-EMS-10) were injected IV into groups of 6 to 8-week-old male athymic nude mice (BALB/cAnBOM). A median of 8.5 colonies/lung was observed among 20 1-LN-EMS-10-injected mice, which was significantly different from the median of 51 colonies/lung produced among 14 1-LN-injected mice (P = 0.0002). This altered phenotype remained stable during 150 days of continuous culture. However, the 1-LN-EMS-10 cells were tumorigenic in 10/10 nude mice injected SC. Single lung tumor colonies recovered from 1-LN-EMS-10-injected mice and reinjected IV into nude mice produced medians of 32-63 colonies/lung. The altered metastatic phenotype resulting from treatment of 1-LN with EMS was reversed by exposure to a noncytotoxic dose of 5-azacytidine, but unaffected by a second exposure to EMS. Collectively these data demonstrate that the metastatic phenotype of these human tumor cells in athymic nude mice can be heritably altered by in vitro exposure to EMS and 5-azacytidine. Analysis of the mechanisms underlying these phenotypic changes may provide insight into parts of the complex process of tumor cell evolution.

Animals↗
PubMed1986

In vitro synergism between hybrid immunotoxins and chemotherapeutic drugs: relevance to immunotherapy of prostate carcinoma.

Cultured prostate carcinoma cells incubated in the presence of a novel hybrid immunotoxin and ricin A chain exhibited synergy with the chemotherapeutic drugs vinblastine, methotrexate, and bleomycin. No cooperative effect was noted with adriamycin. Under conditions where individual components of immunotoxin or chemotherapeutic drug mixtures were nontoxic or minimally toxic the immunotoxin-drug mixture exhibited marked impact on 14C amino acid incorporation into prostate carcinoma cells. Analysis of drug-treated cells by flow cytometry indicated that cells exposed to vinblastine and bleomycin bound hybrid immunotoxin antibody to a greater extent than cells not exposed to these drugs. Adriamycin did not exhibit synergistic cytotoxicity with hybrid immunotoxin. Also, adriamycin did not enhance antibody binding as evaluated by flow cytometry. The fact that hybrid monoclonal antibody-ricin A chain (HIT-RAC) conjugates inhibited uptake of 14C amino acids 3 to 10-fold within 48 h of incubation with target cells and that this inhibition was further increased 2 to 3-fold in conjunction with three out of four chemotherapeutic drugs tested may be attributed to the unique cytotoxicity imposed by the hybrid immunotoxins. The RAC moiety is not chemically coupled to antibody but instead occupies one of the antigen-combining sites of the molecule. In this manner, RAC is closely juxtaposed to the cell membrane of the target cell and is anchored in this position via binding of the remaining antigen-combining site to p40 prostate restricted antigen.

Antibodies, Monoclonal↗
PubMed1978

Diffusion of nitrosamines through protective gloves.

A simple experimental demonstration of the permeability of protective gloves to volatile nitrosamines has been carried out. Rubber and polyvinyl chloride (PVC) gloves were turned inside out and the fingers filled with dilute solutions of nitrosamines in hexane. The outer faces of the fingers were washed with water at various times and the nitrosamine content of these washings determined. From these measurements the proportions of the various nitrosamines passing through the gloves were calculated. For both types of gloves N-nitrosopyrrolidine (NPYR) permeated the fingers most rapidly and to the greatest extent. Only a relatively small amount of N-nitrosodibutylamine (NDBA) was transmitted. It was also established that the rubber gloves themselves did not contain any of the common volatile nitrosamines; N-nitrosomethylphenylamine and N-nitrosodiphenylamine were also absent.

Chromatography, Gas↗
PubMed1977

Simple chemiluminescent detector for the screening of foodstuffs for the presence of volatile nitrosamines.

The construction and subsequent evaluation of an apparatus for the detection of trace amounts of nitrosamines is described. The apparatus consists of a gas chromatograph, a catalytic chamber to generate nitric oxide from eluted nitrosamines, and a chemiluminescent detector to measure the infra-red emission resulting from interaction of this gas with ozone. Examples of the use of the system for determining the nitrosamine concentration in food extracts and other materials are given.

Chromatography, Gas↗
PubMed1977

Correlation of apparent molecular weight and antigenicity of viral proteins: an SDS-page separation followed by acrylamide-agarose electrophoresis and immunoprecipitation.

A simple method is described which combines a sodium dodecyl sulfate polyacrylamide gel electrophoresis (SOS-PAGE) in the first demension with a second electrophoresis, at right angles to the first, into an agarose matrix. The proteins, separated by SDS-PAGE, are exposed to appropriate antisera after the second stage electrophoresis and immunoprecipitates form in the agarose corresponding to the relative electrophoretic mobilities of proteins in the first stage SDS-PAGE separation. The method thus provides a simple, reproducible means for correlating antigenicity with apparent molecular weight of proteins. The technique is qualtitative, but requires smaller quantities of antisera than more conventional immunoelectrophoretic methods such as rocket electrophoresis.

Antigens, Viral↗