Syalil-SSEA1(SLX) levels in supernatant of cultured human lung carcinoma cell lines

The significance of NSE and CEA as a differentiation marker for the cellular heterogeneity of small cell lung cancer

Neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) levels in the culture supernatant of the 65 pulmonary carcinoma cell lines: Small cell lung cancer (SCLC) 18, large cell carcinoma 14, squamous cell carcinoma 14, adenocarcinoma 14 and adenosquamous cell carcinoma 5, were measured by a radioimmunoassay (RIA). The mean value of NSE was 30.8+/-22.4 ng/ml and 9.2+/-8.7 ng/ml in SCLC and non-SCLC, respectively. The mean value of CEA was 15.1+/-20.9 ng/ml and 26.6+/-72.3 ng/ml in SCLC and non-SCLC, respectively. A significant difference in NSE levels was obtained between SCLC cell lines and non-SCLC cell lines. In SCLC cell lines, a significant inverse proportional correlation was observed between NSE and CEA levels. The CEA production tended to be higher in cells with low levels of NSE than in those with high NSE production. With respect to correlation between marker production and growth characteristics of SCLC cells in vitro, significantly higher NSE and lower CEA levels were found in cells growing with floating colony or neurite like characteristics (classic cell type) than those in cells with epithelial or intermediate growth characteristics (variant cell type). A significant positive correlation between NSE levels and the survival periods was found in follow-up studies of 10 patients who underwent surgery with complete resection of the primary tumor. All of 4 long term survivors over 3 years after surgery had significantly high NSE and relatively low CEA producing tumors. The relationship of these markers to clinical status of the patient suggests that an analysis for correlation of NSE and CEA levels in SCLC patients may be useful to discriminate between a pure neuroendocrine SCLC tumor and a mixed small cell/large cell tumor, and in monitoring therapeutic effect and prognosis of each patient.

Infrequent somatic mutations of the p73 gene in various human cancers

AIMS

It has already been reported that loss of heterozygosity (LOH) on chromosome 1p is frequent in a variety of human cancers. This finding implies the presence of some important tumour suppressor genes in this region. p73, a candidate tumour suppressor gene identified recently in chromosome band 1p36.33, encodes a protein highly homologous to p53. To investigate the role of the p73 gene in human carcinogenesis, we studied genetic alterations of this gene in various human cancers.

METHODS

We analysed the entire coding exons as well as their surrounding exon-intron boundaries of the p73 gene in 185 cases of various types of tumours (47 breast cancers, 43 colorectal cancers, 31 gastric cancers, 23 neuroblastomas, 21 lung cancer cell lines, and 20 pancreatic cancer cell lines); they are known as a group of tumours with frequent LOHs in the 1p region. PCR-SSCP analysis was performed and tumours in which aberrant migrating sized bands were observed were subjected to direct sequencing analyses.

RESULTS

Of the 185 cases, only one somatic mis-sense mutation of glutamine from arginine at codon 269 in exon 7 was found in one breast cancer. In addition, several polymorphisms were found at codons 137, 336, 349, and 610, as well as in introns 6, 8, and 9. Monoallelic expression was also observed in pancreatic cancer cell lines.

CONCLUSIONS

Our results suggest that inactivation of the p73 gene does not play a major role in the tumour types analysed in the present study.

Distribution of the CD15 epitope in the mammalian developing lung is opposite in mouse compared with human

The distribution of the expression of the CD15 epitope was characterized by immunohistochemistry in the developing mouse and human lung on embryonic days E9.5-E19 and gestational weeks GW7-GW25, respectively. In the earliest stages in the mouse, the tracheal epithelial cells expressed CD15 on their apical and lateral cell membranes and, in the more proximal regions, also showed a faint cytoplasmatic CD15 expression. Only very few epithelial cells in the bronchial bud regions expressed CD15 on their apical surfaces. In later stages (E12-E17), cells in the proximal parts of the bronchi and bronchioli expressed CD15 on their apical, but also on their lateral membranes, and increasing numbers of cells expressed CD15 cytoplasmatically. Cells in the distal, presumably proliferating, areas of the bud regions were CD15 negative. This distribution pattern of CD15 was consistent until the latest embryonic stages. These results are completely opposite to those found in human developing lung where up to GW20 bronchial and bronchiolar bud regions were CD15 positive, while in the proximal parts of the airways the vast majority of cells were CD15 negative. After GW20, CD15 immunoreactivity in the bud regions vanished and was completely absent on GW25. This difference between human and mouse adds further evidence to profound species differences in the expression of CD15 in various organs, e.g., in the cerebellum or the retina, and should be taken into account when considering functional roles of CD15 and also when relating results from a (transgenic) mouse model to the respective human organ system.

Indomethacin enhances the cytotoxicity of VCR and ADR in human pulmonary adenocarcinoma cells

The ability of anti-inflammatory agents to modulate cellular sensitivity to anticancer drugs was investigated for pulmonary carcinoma cells in vitro. We examined the drug sensitivity of two pulmonary adenocarcinoma cell lines (76-2, 77-4) in the presence of two drugs, an anticancer drug and an anti-inflammatory agent, for 72 hr by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with 96 well plates. Anticancer drugs used for screening test were cyclophosphamide (CPM), mitomycin C (MMC), adriamycin (ADR), 5-fluorouracil (5FU), vindesine (VDS), cisplatin (CDDP), cytarabine (Ara C), methotrexate (MTX), etoposide (VP-16), and vincristine (VCR). Anti-inflammatory agents examined as modulators to anticancer drugs were aspirin, mefenamic acid, ibuprofen, sulindac, piroxicam, phenacetin, dicrofenac, ketoprofen, tolmetin and indomethacin. Screening tests showed indomethacin to be the most effective modulator, resulting in more than a 3-fold increase in cytotoxicity of VCR as compared with that produced by VCR alone. Study of each of the ten anticancer drugs in combination with indomethacin showed VCR to be the most effective anticancer drug in this combination. In 76-2 cells, the concentration of VCR producing 50% growth inhibition (IC50) for VCR alone and VCR in combination with 2 micrograms/ml indomethacin were 1.58 +/- 0.16 and 0.52 +/- 0.1 ng/ml respectively, which represents a 3-fold decrease. In 77-4 cells, the IC50 for VCR alone and VCR in combination with 2 micrograms/ml indomethacin were 2.86 +/- 0.2 and 0.52 +/- 0.11 ng/ml respectively, which represents a 3.8-fold decrease. Our studies indicate that clinically achievable concentrations of indomethacin may be useful in modulating VCR resistance in human pulmonary adenocarcinoma cells, so that combined use of VCR and indomethacin may be of potential clinical significance in the treatment of lung cancer.