Localization of a novel tumor metastasis suppressor region on the short arm of human chromosome 2

Much of the lethality of malignant neoplasms is attributable directly to their ability to develop secondary growths in organs at a distance from the primary tumor mass, whereas few patients die from their primary neoplasm. Little is known about the molecular mechanism of tumor metastasis, however, which is controlled by a variety of positive and negative factors. In the search for metastasis suppressor genes, we have used the microcell-mediated chromosome transfer method and a rat prostate tumor model in SCID mice. When human chromosome 2 was introduced into the highly metastatic rat prostatic tumor cell, AT6.1, the metastatic ability of this cell was significantly (>99%) decreased in animals. An STS-based PCR analysis for 8 hybrid clones indicates that the suppressor activity is located in the p25-22 region of the chromosome. Furthermore, the AT6.1 cell with human chromosome 2 showed a reduced ability to invade Matrigel, suggesting that the suppressor activity is involved in the step of tumor invasion during the progression of prostate cancer. We have also examined the status of the suppressor region on chromosome 2 in human prostate cancer specimens and found that this region was often lost in high-grade tumors. These results suggest that the putative suppressor gene on chromosome 2 is functionally involved in the progression of human prostate cancer. Genes Chromosomes Cancer 28:285-293, 2000.

Immunohistochemical localization of substance P receptors in the midline glia of the developing rat medulla oblongata with special reference to the formation of raphe nuclei

Immunohistochemical localization of the substance P receptor (SPR) was examined in the developing rat medulla oblongata, with special reference to the development of substance P (SP)-immunoreactive neurons which form the medullary raphe nuclei. During development, SPR immunoreactivity was detected in cells lying lateral to the medullary midline from embryonic day 13 (E13) to postnatal day 5 (P5). The SPR-positive cell bodies were located close to the fourth ventricle, and bore long processes extending to the ventral pial surface. This SPR immunoreactivity co-localized with staining for monoclonal antibody 1D11, a specific marker of immature astrocytes. Substance P (SP)-immunoreactive neurons were first detected at E14 in the ventrolateral part of the medulla. By E16 their number had increased and they were arrayed in two rows closely parallel to the SPR-immunoreactive processes of non-neuronal cells. By P1, two separate SP-immunoreactive cell clusters could be recognized at the midline, representing dorsally the nascent raphe pallidus and ventrally the raphe obscurus. In addition, many SP-immunoreactive fibers traveled rostrocaudally in the medulla oblongata, juxtaposed to the midline sheets of SPR-immunoreactive long processes. SPR-immunoreactive processes at the midline were also immunoreactive for S-100, a glia-specific calcium-binding protein that is known to promote axonal growth of raphe neurons. These results suggest that SPR-expressing immature glial cells at the medullary midline are involved in the development of SP-immunoreactive raphe neurons, both in the formation of the medullary raphe nuclei and in axon guidance and growth.

Adenoviral vector-mediated GDNF gene transfer prevents death of adult facial motoneurons

We examined neuroprotective effects of an adenoviral vector encoding glial cell line-derived neurotrophic factor (AxCAhGDNF) on the lesioned adult rat facial motoneurons. After facial nerve avulsion, animals locally injected into the facial canal with AxCALacZ (adenovirus encoding beta-galactosidase gene) or AxCAhGDNF showed expression of beta-galactosidase activity or intense immunolabeling for GDNF in lesioned facial motoneurons, respectively. The treatment with AxCAhGDNF after avulsion significantly prevented the loss of lesioned facial motoneurons, ameliorated choline acetyltransferase immunoreactivity, and suppressed the activity of nitric oxide synthase in these neurons. These results indicate that the adenovirus-mediated gene transfer of GDNF may prevent the degeneration of motoneurons in adult humans with peripheral nerve injury and motor neuron diseases.

Rescue of lesioned adult rat spinal motoneurons by adenoviral gene transfer of glial cell line-derived neurotrophic factor

Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect cranial and spinal motoneurons, that suggests potential uses of GDNF in the treatment of spinal cord injury and motor neuron diseases. We examined neuroprotective effect of human GDNF encoded by an adenovirus vector (AxCAhGDNF) on the death of lesioned adult rat spinal motoneurons. The seventh cervical segment (C7) ventral and dorsal roots and dorsal root ganglia of adult Fisher 344 rats were avulsed, and AxCAhGDNF, AxCALacZ (adenovirus encoding beta-galactosidase gene) or PBS was inoculated in C7 vertebral foramen. One week after the avulsion and treatment with AxCALacZ, the animals showed expression of beta-galactosidase activity in lesioned spinal motoneurons. Animals avulsed and treated with AxCAhGDNF showed intense immunolabeling for GDNF in lesioned spinal motoneurons and expression of virus-induced human GDNF mRNA transcripts in the lesioned spinal cord tissue. Nissl-stained cell counts revealed that the treatment with AxCAhGDNF significantly prevented the loss of lesioned ventral horn motoneurons 2 to 8 weeks after avulsion, as compared to AxCALacZ or PBS treatment. Furthermore, the AxCAhGDNF treatment ameliorated choline acetyltransferase immunoreactivity in the lesioned motoneurons after avulsion. These results indicate that the adenovirus-mediated gene transfer of GDNF may prevent the degeneration of motoneurons in adult humans with spinal cord injury and motor neuron diseases.

The Bacillus subtilis yabG gene is transcribed by SigK RNA polymerase during sporulation, and yabG mutant spores have altered coat protein composition

The expression of six novel genes located in the region from abrB to spoVC of the Bacillus subtilis chromosome was analyzed, and one of the genes, yabG, had a predicted promoter sequence conserved among SigK-dependent genes. Northern blot analysis revealed that yabG mRNA was first detected from 4 h after the cessation of logarithmic growth (T(4)) in wild-type cells and in a gerE36 (GerE(-)) mutant but not in spoIIAC (SigF(-)), spoIIGAB (SigE(-)), spoIIIG (SigG(-)), and spoIVCB (SigK(-)) mutants. The transcription start point was determined by primer extension analysis; the -10 and -35 regions are very similar to the consensus sequences recognized by SigK-containing RNA polymerase. Inactivation of the yabG gene by insertion of an erythromycin resistance gene did not affect vegetative growth or spore resistance to heat, chloroform, and lysozyme. The germination of yabG spores in L-alanine and in a mixture of L-asparagine, D-glucose, D-fructose, and potassium chloride was also the same as that of wild-type spores. On the other hand, the protein preparation from yabG spores included 15-, 18-, 21-, 23-, 31-, 45-, and 55-kDa polypeptides which were low in or not extracted from wild-type spores under the same conditions. We determined their N-terminal amino acid sequence and found that these polypeptides were CotT, YeeK, YxeE, CotF, YrbA (31 and 45 kDa), and SpoIVA, respectively. The fluorescence of YabG-green fluorescent protein fusion produced in sporulating cells was detectable in the forespores but not in the mother cell compartment under fluorescence microscopy. These results indicate that yabG encodes a sporulation-specific protein which is involved in coat protein composition in B. subtilis.

Antibody against a novel, myriocin (ISP-I)-based immunosuppressant, FTY720

An antibody was prepared by immunizing rabbits with an ovalbumin conjugate of 2-amino-2-(2-(4-(4-mercaptobutyl)phenyl)ethyl)propane-1,3-diol HCl (AMPD-4), which contains the essential structure of the novel immunosuppressant FTY720. As the antibody reacted to not only AMPD-4, but also FTY720, it should be useful for immunoassay of FTY720 in body fluids, tissues and cells.

Annexin VII as a novel marker for invasive phenotype of malignant melanoma

Both F10 and BL6 sublines of B16 mouse melanoma cells are metastatic after intravenous injection, but only BL6 cells are metastatic after subcutaneous injection. While examining the genetic difference between the two sublines, we found a marked reduction of annexin VII expression in BL6 cells. In addition, fusion cell clones of both sublines were as poorly metastatic as F10 cells after subcutaneous injection, and contained the annexin VII message as abundantly as F10 cells. Hence, we examined whether the annexin VII expression was correlated with the less malignant phenotype of clinical cases by immunohistochemistry. Immunoreactivities to anti-annexin VII antibody in melanoma cells were evaluated quantitatively by using skin mast cells as an internal positive control. Eighteen patients with malignant melanoma were divided into two groups: lymph node metastasis-negative and positive groups. The ratio of numbers of patients positive versus negative to the antibody was significantly larger in the former than in the latter group. These results not only indicated that annexin VII serves as a marker for less invasive phenotype of malignant melanoma, but also suggested a possible role of annexin VII in tumor suppression.

A new member of the GTPase superfamily that is upregulated in highly metastatic cells

Two sublines of B16 melanoma cells, F10 and BL6, are metastatic after intravenous injection, but only BL6 cells are metastatic after subcutaneous injection. We found a new member of the GTPase superfamily, namely TIB929, which displayed an induction of expression in BL6 cells. It conserved three consensus sequences for GTP-binding site motifs and showed a significant homology to the yeast Gtr2 gene throughout the coding sequence. TIB929 was expressed ubiquitously in human tumor cells, with a marked expression in highly metastatic cells. TIB929 was mapped on mouse chromosome 4D, syntenic to human chromosome 1p. The results suggested an involvement of TIB929 in malignant progression.

Characterization of the yrbA gene of Bacillus subtilis, involved in resistance and germination of spores

Insertional inactivation of the yrbA gene of Bacillus subtilis reduced the resistance of the mutant spores to lysozyme. The yrbA mutant spores lost their optical density at the same rate as the wild-type spores upon incubation with L-alanine but became only phase gray and did not swell. The response of the mutant spores to a combination of asparagine, glucose, fructose, and KCl was also extremely poor; in this medium yrbA spores exhibited only a small loss in optical density and gave a mixture of phase-bright, -gray, and -dark spores. Northern blot analysis of yrbA transcripts in various sig mutants indicated that yrbA was transcribed by RNA polymerase with sigma(E) beginning at 2 h after the start of sporulation. The yrbA promoter was localized by primer extension analysis, and the sequences of the -35 (TCATAAC) and -10 (CATATGT) regions were similar to the consensus sequences of genes recognized by sigma(E). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of proteins solubilized from intact yrbA mutant spores showed an alteration in the protein profile, as 31- and 36-kDa proteins, identified as YrbA and CotG, respectively, were absent, along with some other minor changes. Electron microscopic examination of yrbA spores revealed changes in the spore coat, including a reduction in the density and thickness of the outer layer and the appearance of an inner coat layer-like structure around the outside of the coat. This abnormal coat structure was also observed on the outside of the developing forespores of the yrbA mutant. These results suggest that YrbA is involved in assembly of some coat proteins which have roles in both spore lysozyme resistance and germination.

The Bacillus subtilis yaaH gene is transcribed by SigE RNA polymerase during sporulation, and its product is involved in germination of spores

The expression of 21 novel genes located in the region from dnaA to abrB of the Bacillus subtilis chromosome was analyzed. One of the genes, yaaH, had a predicted promoter sequence conserved among SigE-dependent genes. Northern blot analysis revealed that yaaH mRNA was first detected from 2 h after the cessation of logarithmic growth (T(2)) of sporulation in wild-type cells and in spoIIIG (SigG(-)) and spoIVCB (SigK(-)) mutants but not in spoIIAC (SigF(-)) and spoIIGAB (SigE(-)) mutants. The transcription start point was determined by primer extension analysis; the -10 and -35 regions are very similar to the consensus sequences recognized by SigE-containing RNA polymerase. A YaaH-His tag fusion encoded by a plasmid with a predicted promoter for the yaaH gene was produced from T(2) of sporulation in a B. subtilis transformant and extracted from mature spores, indicating that the yaaH gene product is a spore protein. Inactivation of the yaaH gene by insertion of an erythromycin resistance gene did not affect vegetative growth or spore resistance to heat, chloroform, and lysozyme. The germination of yaaH mutant spores in a mixture of L-asparagine, D-glucose, D-fructose, and potassium chloride was almost the same as that of wild-type spores, but the mutant spores were defective in L-alanine-stimulated germination. These results suggest that yaaH is a novel gene encoding a spore protein produced in the mother cell compartment from T(2) of sporulation and that it is required for the L-alanine-stimulated germination pathway.

Assessment of mucosal immune response in genitourinary tract using urine

A novel method to assess mucosal immune response in the genitourinary mucosa after immunization with a mucosal vaccine has been developed. In this method, secretory IgA antibody is measured by a highly sensitive enzyme immunoassay (immune-complex transfer enzyme immunoassay) using urine as a specimen. The urinary IgA antibody response could be detected by the immune-complex transfer enzyme immunoassay. In contrast, a conventional enzyme immunoassay (enzyme-linked immunosorbent assay (ELISA)) could not detect this response because of its low sensitivity. Because urine samples can be collected easily and nontraumatically, not only from experimental animals but also from humans, both males and females, the present method may be applicable for assessing the protective efficacy of candidates for mucosal vaccines against sexually transmitted microorganisms, such as human immunodeficiency virus. Furthermore, the usefulness of this method for novel mucosal vaccine formulae was shown for a model in which vaccine antigen and Bordetella pertussis adjuvant were adsorbed onto CaCO, and enclosed in enteric coated capsules.

Assembly of the CotSA coat protein into spores requires CotS in Bacillus subtilis

The CotSA protein, encoded by cotSA (ytxN) of Bacillus subtilis, was detected from the cells at 5 h after the onset of sporulation (T5) and in the spore coat of wild-type cells, but not in cotE, cotS, gerE, or cotSA mutant spores. CotSA was also detected in the sporangium at T5 to T7 but not in the sporangium at T18 of cotS mutant cells, while the incorporation of CotS into the coat was not dependent upon CotSA. These results suggested that CotSA was synthesized simultaneously with CotS during T5 to T7 of sporulation and assembled into the coat dependent upon CotS.

Determination of the bioavailability of intranasal elcatonin in humans: development of a sandwich transfer enzyme immunoassay for elcatonin

A sandwich transfer enzyme immunoassay for elcatonin (ECT) and its usability for the pharmacokinetic study are described. The anti-salmon calcitonin (SCT) antibody was used for the present assay. The assay procedure consisted of the reaction of ECT with 2,4-dinitrophenylbiotinyl anti-SCT IgG and anti-SCT Fab'-beta-D-galactosidase conjugate, trapping onto (anti-2,4-dinitrophenyl bovine serum albumin) IgG-coated polystyrene balls, eluting with epsilonN-2,4-dinitrophenyl-L-lysine and transferring to streptavidin-coated polystyrene balls and fluorometric detection of beta-D-galactosidase activity. The practical detection limit of ECT was 0.15 pg (44 amol)/50 microl of sample and 3 pg/ml as the concentration. The application of this method has enabled us to directly estimate the bioavailability of ECT dosed intranasaly at a therapeutic level (100 IU, 17 microg) for its anti-osteoporotic effect as compared to an intramuscular dose (40 IU, 6.7 microg). The pharmacokinetic parameters of the intranasal ECT (n = 6) thus estimated were as follows: the area underthe serum concentration-time curve (AUC) = 2,570 +/- 1,650 (SD) pg x min/ml, and the maximal concentration (Cmax) = 60 +/- 25 (SD) pg/ml with the maximal time (Tmax) = 17.5 +/- 6.9 (SD) min, when the AUC for the intramuscular ECT (n = 9) = 9,460 +/- 5,870 (SD) pg x min/ml and the Cmax = 165 +/- 79 (SD) pg/ml with the Tmax = 16.1 +/- 4.2 (SD) min.

Development of a highly sensitive and specific two-site enzyme immunoassay for parathyroid hormone (1-34): application to pharmacokinetic study on intranasal parathyroid hormone (1-34) in human

A highly sensitive and specific two-site enzyme immunoassay for parathyroid hormone (1-34) (PTH(1-34)) and its usability for the pharmacokinetic study are described. Plasma samples were incubated simultaneously with 2,4-dinitrophenylated anti-PTH(1-34) IgG and anti-PTH(1-34) Fab'-beta-D-galactosidase conjugate. The immune complex formed of the three components was trapped onto (anti-2,4-dinitrophenyl group) IgG-coated polystyrene balls. beta-D-Galactosidase activity bound to the polystyrene balls was assayed by fluorometry. The practical detection limit of PTH(1-34) was 50 fg (12 amol)/0.05 ml of sample and 1 pg/ml as the concentration and practically no interference occurred by PTH(1-84) and PTH-related protein (1-34) up to 300 pg/ml and 10 ng/ml, respectively. The application of this method has enabled us to directly estimate the bioavailability of PTH(1-34) dosed intranasally at the prescribed level (0.090 mg). The pharmacokinetic parameters of the intranasal PTH(1-34) (n = 4) thus estimated were as follows: the area under the plasma concentration-time curve (AUC) = 20,500+/-15,900(SD) pg.min/ml; the mean residence time (MRT) = 194+/-16.3(SD) min; and the maximal concentration (Cmax) = 98+/-51 (SD) pg/ml with the maximal time (Tmax) = 35.0+/-12.2(SD) min.

A sandwich transfer enzyme immunoassay for salmon calcitonin: determination of the bioavailability of intranasal salmon calcitonin in human

A sandwich transfer enzyme immunoassay for salmon calcitonin (SCT) and its usability for the pharmacokinetic study are described. The assay procedure consisted of the reaction of SCT with 2,4-dinitrophenyl biotinyl anti-SCT IgG and anti-SCT Fab'-beta-galactosidase conjugate, trapping onto (anti-2,4-dinitrophenyl bovine serum albumin) IgG-coated polystyrene balls, eluting with epsilon N-2,4-dinitrophenyl-L-lysine and transferring to streptavidin-coated polystyrene balls and fluorometric detection of beta-D-galactosidase activity. The practical detection limit of SCT was 0.05 pg (15 amol)/50 microliters of sample and 1 pg/ml as the concentration. The application of this method has enabled us to directly estimate the bioavailability of SCT dosed intranasally at the therapeutic level (160 IU, 31 micrograms) for its anti-osteoporotic effect as compared to an intramuscular dose (10 IU, 1.9 micrograms). The pharmacokinetic parameters of the intranasal SCT (n = 6) thus estimated were as follows: the area under the blood concentration-time curve (AUC) 9400 +/- 5400 (SD) pg.h/ml, and the mean residence time (MRT) = 42 +/- 14 (SD) min, when the AUC for the intramuscular SCT (n = 3) = 5600 +/- 2000 (SD) pg.h/ml and the MRT = 39 +/- 19 (SD) min.

Plasma level monitoring of nasal salmon calcitonin in the rat by a heterogeneous two-site enzyme immunoassay

The experimental and clinical effectiveness of nasal salmon calcitonin (SCT) for treatment of osteoporosis in humans has been well established, but none is known yet about the pharmacokinetic property in relation to therapeutic efficacy, especially when used in a therapeutic dose range. This preclinical study was designed to evaluate such a property, first of all in rats, using a novel heterogeneous two-site enzyme immunoassay that has allowed us to evaluate the pharmacokinetic property of parenteral SCT in rats due to the high sensitivity (the detection limit = 2 pg of SCT/ml of plasma). It was found that as early as 10 min after the nasal dosing of 1.25, 5, or 20 U/rat, the SCT immunoactivity became detectable in plasma and thereafter it waned rapidly with time. Hypocalcemia developed in a dose-dependent manner, but with a delay of approximately 20 min from the peak of the immunoactivity and lasted hours. The pharmacokinetic parameters measured for the doses (1.25, 5, and 20 U/rat) were as follows; the AUCs (pg.hr/ml) = 20.8, 89.0, and 189, and the MRTs (min) = 52, 54, and 45, respectively. The results appear to suggest: (1) the unexpected quick transfer of nasal SCT into and from the circulation, (2) a delayed onset of hypocalcemia and possibly its anti-osteopenic action, both of which may last longer, (3) that keeping the plasma SCT above the in vitro anti-osteoclastic level (approximately 1 pM) only for a few hours per 2 days would be enough for inducing the distinct anti-osteopenic effect in rats, and (4) the feasibility of designing the clinical study as to the pharmacokinetics and pharmacodynamics of nasal SCT on humans.

Regenerative process after experimental injury of hypoglossal nerves in guinea pigs

The nerve regenerative process has been investigated by many studies. However, the quantification of the degree of crush of peripheral nerves has not yet been performed. The aim of this study was to determine and standardize the ligature intensity and crush level of the hypoglossal nerve of guinea pigs. The compound action potentials evoked by electric stimulation were used as an index of the degree of nerve crush. To demonstrate nerve regeneration after ligating and crushing of the right hypoglossal nerve, fluorescein isothiocynate conjugated cholera toxin-B subunit (CTb-FITC) was injected into the intact fiber of the left hypoglossal nerve, and the central side from the crushed region of the right hypoglossal nerve fiber. The total cross sectional area of the retrograde-labeled hypoglossal motoneurons was investigated under a confocal laser scanning microscope. The results of the evaluation using CTb-FITC indicated that the nerve regeneration occurred from two weeks after crush and recovered in six weeks.

C-ABI3, the carrot homologue of the Arabidopsis ABI3, is expressed during both zygotic and somatic embryogenesis and functions in the regulation of embryo-specific ABA-inducible genes

A carrot gene homologous to the ABI3 gene of Arabidopsis was isolated from a carrot somatic embryo cDNA library and designated C-ABI3. The sequence of C-ABI3 was very similar to those of ABI3 of Arabidopsis and VP1 of maize in certain conserved regions. The expression of C-ABI3 was detected specifically in embryogenic cells, somatic embryos and developing seeds. Thus, expression of C-ABI3 was limited to tissues that acquired desiccation tolerance in response to endogenous or exogenous abscisic acid (ABA). Endogenous levels of ABA in seeds increased transiently and then desiccation of seeds started. The expression of C-ABI3 in developing seeds was observed prior to the increase in levels of endogenous ABA that was followed by desiccation of seeds. In transgenic mature leaves in which C-ABI3 was ectopically expressed, expression of ECP31, ECP63 and ECP40 was induced by treatment with ABA, which indicates that the expression of ECP genes was controlled by the pathway(s) that involved C-ABI3 and ABA. This suggests that C-ABI3 has the same function as VP1/ABI3 factor in carrot somatic embryos.

Human chromosome 16 suppresses metastasis but not tumorigenesis in rat prostatic tumor cells

Genomic aberrations at the chromosome 16q arm are one of the most consistent abnormalities observed by loss of heterozygosity and comparative genomic hybridization analyses in human prostate cancer, suggesting that there are tumor suppressor or metastasis suppressor genes encoded by this chromosomal region. To functionally identify such suppressor genes, we have conducted microcell-mediated chromosome transfer to introduce human chromosome 16 into the highly metastatic Dunning rat prostatic cancer cell line, AT6.1. The metastatic ability of the resultant microcell hybrid clones was then tested in a standard spontaneous metastasis assay using SCID mice. When the microcell-mediated chromosome transfer hybrid cells containing whole human chromosome 16 were injected, the number of metastatic lesions in the lung was significantly reduced as much as 99% on average. Therefore, chromosome 16 has a strong activity to suppress the metastatic ability of AT6.1 cells while it did not affect the tumorigenesis and tumor growth rate. A PCR analysis of various microcell hybrid clones with sequence-tagged site markers indicates that the metastasis suppressor activity is located in the q24.2 region of chromosome 16. Our results are consistent with the previous finding that the region of human chromosome 16q has frequent loss of heterozygosity in prostate cancer patients and suggest that there is a metastasis suppressor gene in this region that may play an important role in the progression of prostate cancer.

Cloning of a novel gene yrbB, encoding a protein located in the spore integument of Bacillus subtilis

A DNA fragment (2.7 kbp) containing three deduced open reading frames, orf1, orf2 and orf3 (partial sequence), was isolated from the genomic library of Bacillus subtilis using an antiserum raised against spore integument, and was sequenced. orf2 was 519 nucleotides long and encoded a protein of 172 amino acids with a predicted molecular size of 19,552, corresponding to the protein which reacted with the antiserum. Immunoelectron microscopic observation indicated that YrbB, the product of orf2, was located within the spore integument, mainly in the cortex layer with a part in the inner region of the coat layer.

The expression of the KAI1 gene, a tumor metastasis suppressor, is directly activated by p53

KAI1 is a tumor metastasis suppressor gene that is capable of inhibiting the metastatic process in animals. The expression of the KAI1 gene also is found to be down-regulated during the tumor progression of prostate, breast, lung, bladder, and pancreatic cancers in humans, and this down-regulation appears to be at or posttranscription level. We have found that the tumor suppressor gene p53 can directly activate the KAI1 gene by interacting with the 5' upstream region. The p53 responding region is located at approximately 860 bases upstream of the transcriptional initiation site, and it contains a typical tandem repeat of the p53 consensus-binding sequence. A gel-shift mobility analysis showed that this sequence indeed had the ability to bind to the purified p53 protein. Mutations of this sequence abolished the responsiveness to p53 and also the binding ability to the p53 protein. Furthermore, immunohistochemical analysis of 177 samples of human prostate tumors revealed that the expression of the KAI1 gene was correlated strongly to that of the p53 gene and that the loss of these two markers resulted in poor survivals of patients. Our data indicate a direct relationship between p53 and KAI1 genes and suggest that the loss of p53 function, which is commonly observed in many types of cancer, leads to the down-regulation of the KAI1 gene, which may result in the progression of metastasis.

Lifestyle and gastric cancer: a case-control study

In Hokkaido, Japan, in order to investigate the etiological relation between gastric cancer and lifestyle, a case-control study was conducted, employing 242 cases with this cancer and 484 controls matched for sex, age, and place of residence. Eating meals within a short time, eating until full, irregularity in the time for supper, having dentures, and lack of teeth showed high odds ratios. Putting an excess digestive burden on the stomach by insufficient chewing promotes the development of this cancer. Stress, long working time, irregularity in sleeping time, and gray hair in males showed high odds ratios. A stressful life may be promotive for this cancer through depressed immunoresistance. Logistic regression analysis showed that those who ate meals rapidly, had strong stress and had lost many teeth were at high risk. The linear trend of the dose-response relationship between the number of teeth lost and the odds ratio was highly significant. To avoid stress, to chew foods sufficiently, and to maintain the health of the oral cavity can help to prevent gastric cancer.

Identification of a novel metastasis-suppressor region on human chromosome 12

There is a critical need for markers that can be used to predict accurately the malignant potential of histological prostate cancers (J. T. Isaacs. Am. J. Pathol., 150: 1511-1521, 1997). Metastasis-suppressor genes are attractive candidates for marker development because, by definition, their loss should be associated with the acquisition of metastatic ability. In an effort to identify such genes, a single copy of human chromosome 12, tagged with the neomycin resistance gene, was introduced into highly metastatic Dunning AT6.1 prostate cancer cells by microcell-mediated chromosomal transfer. Thirty-two AT6.1-12 clonal cell lines were established and the region(s) of chromosome 12 retained was determined by sequence tagged site-based PCR analysis. Representative AT6.1-12 clones containing overlapping regions of chromosome 12 were characterized cytogenetically and were shown to have a normal complement of parental AT6.1 rat chromosomes. Fluorescence in situ hybridization, performed on representative AT6.1-12 hybrids, demonstrated a single human chromosome 12-specific signal. The metastatic ability of six representative clones was tested in immunodeficient mice. All of the AT6.1-12 clones showed the same in vivo growth rates as the control AT6.1-neo cells. Clonal cell lines that contained a conserved approximately 70-cM portion of chromosome 12 (e.g., AT6.1-12-8, -8-1, and -8-3), showed a >30-fold suppression in the number of macroscopic surface lung metastases. Mice that received injections of these cells developed a mean number 4 lung metastases whereas mice that received injections of other AT6.1-12 hybrids (lacking the approximately 70-cM region) or AT6.1-neo control cells, developed a mean number of 140 metastases. Interestingly, histological examination of the lungs of the mice that received injections of AT6.1-12-8 cells showed essentially no microscopic metastases. These findings suggest that a gene(s) encoded by the approximately 70-cM portion of human chromosome 12 suppresses an early step in the metastatic cascade.