Overexpression of SCC antigen and cyclins in an adenoid squamous carcinoma cell line derived from the maxillary sinus.

Squamous cell carcinoma antigen (SCC-Ag) is produced by the two almost identical, tandemly arrayed genes, SCCA1 and SCCA2. In this study, we investigated the mechanism of increased expression of SCC-Ag in a cell line SCCMM derived from an aggressive adenoid SCC with high titer of SCC-Ag in the patient serum. The differential polymerase chain reaction using specific primers for SCCA1 and SCCA2 revealed no gene amplification in SCCMM. However, RT-PCR demonstrated that levels of SCCA1 and SCCA2 mRNAs in SCCMM were 80- and 120-fold higher than those in CaSki as a reference SCC cell, respectively. Western blot analysis showed that the levels of these two SCC-Ag proteins in SCCMM were 15-fold higher than those in CaSki, suggesting that expression of the SCC-Ag in SCCMM was controlled at both the transcriptional and post-transcriptional levels. To investigate highly malignant character of SCCMM, expression of cell cycle regulatory proteins was investigated by Western blotting. Cyclin E and cyclin B1 were expressed at approximately 100-fold higher levels in SCCMM than in CaSki, but Cip/Kip cyclin-dependent kinase inhibitors (CDKIs) were expressed at low levels and p16 and p19 ink4 CDKIs were not detected. These results suggest that the aggressive growth of SCCMM is due, at least in part, to large increases in cyclin E and cyclin B1 expression with low levels of CDKIs.

Dual antitumor effects of 5-fluorouracil on the cell cycle in colorectal carcinoma cells: a novel target mechanism concept for pharmacokinetic modulating chemotherapy.

5-Fluorouracil (5-FU) is one of the most widely used anticancer agents for advanced colorectal carcinoma, but its response rate is only 15%. The "pharmacokinetic modulating chemotherapy" (PMC) regimen that we have advocated has proved to be highly effective in treating colorectal carcinoma. PMC consists of a continuous i.v. infusion of 5-FU over 24 h for 1day a week at 600 mg/m2/day, and an oral dose of uracil-tegafur (UFT), a 5-FU derivative, at 400 mg/day for 5-7 days per week, repeated every week for more than 6 months. Assays of 5-FU in 23 patients receiving this treatment showed serum concentrations ranging from 88 to 1,323 ng/ml. We then analyzed the effects of clinically relevant concentrations of 5-FU found in colorectal cancer patients treated with the PMC regimen on the growth of three human colorectal adenocarcinoma cell lines, SW480 and COLO320DM (mutant p53) and HCT116 (wild-type p53). Exposure of these three cell lines to 5-FU resulted in growth inhibition in a dose-dependent manner. Exposure to 100 ng/ml of 5-FU in SW480 and COLO320DM caused G1 arrest after 24 h and G2 arrest after 72-144 h, and only a minority of the cell population showed apoptotic features, which indicated that most of the cells were killed through mitotic catastrophe, nonapoptotic cell death. On the contrary, exposure to 1000 ng/ml of 5-FU in SW480 and COLO320DM resulted in G1-S-phase arrest and the induction of apoptosis throughout the experimental period. Nuclear cyclin B1 expression was markedly induced with exposure to 100 ng/ml of 5-FU in SW480 and COLO320DM; and expression of 14-3-3sigma protein, a cell cycle inhibitor in the GG phase, was induced in SW480. ICT116 responded to lower concentrations of 5-FU more rapidly: G2 arrest was seen after 24-72 h of exposure to 10 ng/ml of 5-FU, and G,1rrest was seen after 12-24 h of exposure to 100 ng/ml. These results show that 5-FU acts via two different pathways, depending on dose: (a) G,1S-phase cell cycle arrest and apoptosis at 1,000 ng/ml in SW480 and COLO320DM, and 100 ng/ml in HCT116; and (b) G2-M-phase cell cycle arrest and mitotic catastrophe at 100 ng/ll in SW480 and COLO320DM, and 10 ng/ml in HCT116. These results suggest that the efficacy of our PMC regimen is based on targeting at least two different phases of the cell cycle. In our clinical trial, we showed efficacy independent of p53 status, ascertained by cell kinetic analysis in vitro, which may lead to a novel concept of schedule-oriented biochemical modulation of this drug.

Cytogenetic analysis of de novo acute myeloid leukemia with trilineage myelodysplasia in comparison with myelodysplastic syndrome evolving to acute myeloid leukemia.

Characteristics of karyotypes were analyzed in de novo acute myeloid leukemia (AML) with trilineage myelodysplasia (AML/TMDS) at initial diagnosis and compared with myelodysplastic syndrome (MDS) cases that had evolved to AML (MDS/AML). Abnormal karyotypes were seen in 11 of 19 patients with AML/TMDS and 13 of 16 MDS/AML cases. Trisomy 8 was observed in 3 AML/TMDS cases as a sole anomaly and was also present in 3 MDS/AML cases but not as a sole finding. Although MDS/AML frequently displayed monosomies or long-arm deletions of chromosome 5, 7 and 9, only one case exhibited long-arm deletion (of chromosome 7) in AML/TMDS. Two or more chromosome aberrations were found in some cases in both groups. These findings suggest that AML/TMDS had passed through several preleukemic stages at diagnosis, as has been well documented in MDS and MDS/AML. Additionally, clonal evolution may have already occurred in AML/TMDS, as MDS transformed to AML is associated with clonal evolution.

Usefulness of K-ras gene mutation at codon 12 in bile for diagnosing biliary strictures.

Point mutations of the K-ras gene at codon 12 are often detected in the pancreatic juice of patients with pancreatic cancer. Detection of these mutations may, thus, have diagnostic implications. K-ras mutations may also have diagnostic potential for other biliary tumors. We sought to detect K-ras mutations in DNA obtained from bile in patients with biliary tract cancers, pancreatic cancer and benign biliary disease but who had obstructive jaundice. In 35 patients, bile was collected during percutaneous transhepatic choledocal drainage (PTCD) catheters. K-ras gene mutations at codon 12 in the samples were examined using mutant-allele-specific-amplification (MASA). We compared these results with cytological analyses of bile. K-ras mutations at codon 12 in bile were detected in 11 of 14 (79%) of the patients with biliary duct cancer, 3 of 9 (33%) with pancreatic cancer but not in patients with gallbladder cancer (n=3), papilla of Vater's cancer (n=3) or benign biliary diseases (n=6). In the patients, where cytological evaluation did not reveal malignant cells, K-ras mutations in bile were detected in 5 of 7 (71%) patients with biliary duct cancer and 2 of 5 (40%) with pancreatic cancer. This approach, when used in conjunction with bile cytology, may improve the yield in diagnosing suspected malignant tumors of the pancreatic-biliary system.

Founder effect of a prevalent phenylketonuria mutation in the Oriental population.

A missense mutation has been identified in the human phenylalanine hydroxylase [PAH; phenylalanine 4-monooxygenase; L-phenylalanine, tetrahydrobiopterin:oxygen oxidoreductase (4-hydroxylating), EC 1.14.16.1] gene in a Chinese patient with classic phenylketonuria (PKU). A G-to-C transition at the second base of codon 413 in exon 12 of the gene results in the substitution of Pro413 for Arg413 in the mutant protein. This mutation (R413P) results in negligible enzymatic activity when expressed in heterologous mammalian cells and is compatible with a classic PKU phenotype in the patient. Population genetic studies reveal that this mutation is tightly linked to restriction fragment length polymorphism haplotype 4, which is the predominant haplotype of the PAH locus in the Oriental population. It accounts for 13.8% of northern Chinese and 27% of Japanese PKU alleles, but it is rare in southern Chinese (2.2%) and is absent in the Caucasian population. The data demonstrate unambiguously that the mutation occurred after racial divergence of Orientals and Caucasians and suggest that the allele has spread throughout the Orient by a founder effect. Previous protein polymorphism studies in eastern Asia have led to the hypothesis that "northern Mongoloids" represented a founding population in Asia. Our results are compatible with this hypothesis in that the PKU mutation might have occurred in northern Mongoloids and subsequently spread to the Chinese and Japanese populations.

A simple method of lysosomal hydrolase assay in a single somatic cell and its application.

A new and simple assay method for lysosomal hydrolase in a single cultured skin fibroblast is described. Using 4-methylumbelliferyl-glycosides and ordinary laboratory equipment, the activity can be measured with the highest sensitivity of 0.5 pmol of 4-methylumbelliferone released from the substrates. Two systems were compared and the methods described proved reliable for the diagnosis of several variants of beta-galactosidase deficiency.

Hypersialyloligosacchariduria in mucolipidoses: a method for diagnosis.

A method is described for the detection of abnormal oligosaccharides in a small (5 ml) volume of urine, employing filtration on a Bio Gel P-6 column, determination of neutral sugar and bound sialic acid, and determination of creatinine content. With this method increased urinary excretion of sialic acid-rich oligosaccharides has been detected in nine patients with mucolipidoses (five cases of mucolipidosis II and four patients of mucolipidosis, with beta-galactosidase deficiency). The filtration patterns of oligosaccharides in mucolipidoses were clearly distinguishable from those in other inborn errors of metabolism. Total excreted oligosaccharides were increased 5--30-fold in these patients; mucolipidosis II, 640--1350 microgram neutral sugar/mg creatinine; control 54 +/- 20 microgram neutral sugar/mg creatinine. The oligosaccharides consisted of three sialic acid-rich fractions and were common in both types of mucolipidosis. Our data indicate that hypersialyoligosacchariduria is the main biochemical feature of both types of mucolipidosis.

A hypotetraploid human T lymphoid cell line established by cell fusion.

A human T lymphoid cell line was established by cell hybridization technique from peripheral blood leucocytes of a patient with Sezary syndrome. The cells beared the surface antigens of human T lymphocyte specificity as demonstrated by immune cytolysis tests, but did not form E rosettes with sheep red blood cells. Isozyme patterns of enzymes in this line such as lactate dehydrogenase, glucose 6-phosphate dehydrogenase and esterase were of human type. The line had 79 chromosomes in modal number. This case supports the proposal that the production of tetraploids is favourable for establishment of cell lines.

DNA repair characteristics and skin cancers of xeroderma pigmentosum patients in Japan.

Fifty xeroderma pigmentosum patients in Japan were examined for clinical characteristics and DNA repair of their cells, Skin cancers developed in 22 patients. Most of the patients without skin cancers were children, except for 5 older patients who had intermediate or nearly normal levels of DNA repair in their cells. All patients younger than 10 years old had no or very low activity of unscheduled DNA synthesis after ultraviolet light irradiation. Three genetic complementation groups, A, D, and E, and variants were found. Many Group A patients and no Group C patients characterized Japanese patients, compared with those in Europe and the United States, where Group C patients were most frequent. The high frequency of patients with low DNA repair capacities in their cells may account for the apparent high frequency of xeroderma pigmentosum patients in Japan. Age distribution of the cancer-bearing patients and their DNA repair characteristics suggest that almost all xeroderma pigmentosum patients will develop skin cancers unless their cells have nearly normal levels of DNA repair.