Association of biofilm production of coagulase-negative staphylococci with expression of a specific polysaccharide intercellular adhesin.

An association between adherent biofilm production on tissue culture plates and expression of a specific polysaccharide intercellular adhesion (PIA), which is functionally involved in cell clustering, was investigated for 179 Staphylococcus epidermidis isolates. Of the S. epidermidis strains, 50.8% were biofilm producers (A570 of > 0.1). There was a significant positive association between biofilm production and PIA expression: 86.8% of biofilm-producing S. epidermidis strains produced PIA as detected with a specific coagglutination assay. In contrast, 88.6% of the biofilm-negative isolates did not express PIA (P < .001). A linear association between the amount of PIA produced as detected by inhibition ELISA and the amount of biofilm produced was established for 49 S. epidermidis strains, representing a continuum from biofilm-negative to strongly biofilm-producing (r = .81, P < .001). Apparently, PIA is important for biofilm accumulation in the majority of clinical S. epidermidis isolates.

Epidermal growth factor receptor expression in human lung cancer cell lines.

Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) cell lines were studied for epidermal growth factor (EGF) receptor expression. All NSCLC cell lines tested (eight of eight) had specific EGF binding sites, whereas only five of 11 SCLC cell lines bound EGF. NSCLC and SCLC cell lines expressed the same type of high affinity EGF binding sites with a Kd of 0.5 to 4.5 nM; however, NSCLC cells bound significantly more EGF than SCLC cell lines. The amount of binding sites in NSCLC cells ranged between 71 and 1,000 fmol/mg of protein and in SCLC cells, between 26 and 143 fmol/mg of protein. The two SCLC cell lines with EGF binding values within the range of NSCLC belonged to the variant subtype of SCLC. By means of an anti-erbB serum and indirect radioimmunoprecipitation, a strong Mr approximately 170,000 protein band could be detected in the NSCLC cell lines. This protein corresponds to the EGF receptor molecule. Its identity was proven by competition with excess erbB antigen for the antibody during the radioimmunoprecipitation. Furthermore, this Mr 170,000 protein exhibited protein kinase activity as evidenced by in vitro autophosphorylation. The radioactivity incorporated into the Mr 170,000 band in radioimmunoprecipitation and protein kinase assays was 10 to 100 times lower in these SCLC cell lines which were positive in the EGF binding assay compared to the NSCLC cell lines. We conclude that NSCLC in contrast to SCLC expresses high levels of EGF receptors which may be used to facilitate the differential diagnosis in some cases of lung cancer. These data suggest that EGF may play a role in growth and differentiation of NSCLC.

Characterization of the state of differentiation of six newly established human non-small-cell lung cancer cell lines.

Six new non-small-cell lung cancer (NSCLC) cell lines were established directly from human tissue or indirectly via nude mouse xenografts in serum-supplemented media with success rates of 8% and 13%, respectively. They comprised one adenocarcinoma (ADLC-5M2), two squamous cell carcinomas (EPLC-32M1, EPLC-65H), two large cell carcinomas (LCLC-97TM1, LCLC-103H), and one malignant biphasic mesothelioma (MSTO-211H). All cell lines grew adherent to culture vessels with population doubling times (PDT) of 16-40 h, formed colonies in soft agarose with efficiencies of 0.1%-5.1%, and all grew in athymic nude mice. Xenograft histologies appeared as follows: (a) undifferentiated carcinomas with feeble resemblance to the original tumors in the case of adenocarcinomas and squamous cell carcinomas; (b) large cell carcinoma with high resemblance to the original tumor; (c) an undifferentiated tumor with predominance of large epithelial cells and few fibrous cells in the case of mesothelioma. Human chorionic gonadotropin (HCG) was found by radioimmunoassay and high-affinity binding sites for epidermal growth factor (EGF) by radio-receptor assay in 4/4 cell lines. A very low activity of L-DOPA decarboxylase (DDC) was detectable only in the adenocarcinoma cell line. All cell lines overexpressed the c-myc protooncogene, and no gene rearrangement or amplification was observed. Chromosome analysis revealed modal chromosome numbers of 70-73 in ADLC-5M2, EPLC-32M1, EPLC-65H, and MSTO-211H. Cell lines derived from large cell carcinoma had modal values of 65 and 170 and a wider chromosome distribution than all other cell lines. A NSCLC specific chromosomal aberration has been undetectable until now. These cell lines may aid in elucidating the biology of NSCLC and its interrelationship to other lung tumors.

Peptides and growth factors in small cell lung cancer: production, binding sites, and growth effects.

We investigated the production, binding to cell membranes, and influence on cell proliferation of peptides and growth factors in 4 classic, 5 transitional, and 5 variant SCLC cell lines. Glucagon, neurotensin, and TGF-alpha were present in all cell lines. Bombesin was predominantly found in classic cell lines and insulin in variant cell lines. Neurokinin A, calcitonin, CGRP, GHRF, somatostatin, and CNTF were detectable in some cell lines without prevalence for a particular cell type. We could not detect AVP, growth hormone, neuropeptide Y, substance P, VIP, and NGF. Insulin binding sites were present on 11/14 cell lines, and some cell lines specifically bound bombesin, calcitonin, and EGF. Growth effects were detectable for insulin, GRP-related peptides, tachykinins, and VIP. Using serum-free conditions, insulin and VIP had a growth stimulating effect in liquid culture at nanomolar concentrations. Bombesin and neuromedin B stimulated the clonal growth at a concentration of 3-30 nM. The tachykinins neurokinin A, neurokinin B, physalaemin, and eledoisin inhibited the clonal and mass culture growth with a peak effect in the range of 0.1 to 10 pM. Peptide-induced stimulating and inhibiting effects were within a magnitude of 2-fold. All other peptides and growth factors tested, including ACTH, AVP, calcitonin, glucagon, neurotensin, somatostatin, EGF, CNTF, and NGF did not affect the growth of SCLC. We conclude that the growth of SCLC is partly controlled by such peptides in an autocrine/paracrine fashion.