Functional conservation between fission yeast moc1/sds23 and its two orthologs, budding yeast SDS23 and SDS24, and phenotypic differences in their disruptants

The moc1/sds23 gene was isolated to induce sexual development of a sterile strain due to overexpression of adenylate cyclase in Schizosaccharomyces pombe. Here, we studied the functional conservation between moc1/sds23 and its two orthologs SDS23 and SDS24 in Saccharomyces cerevisiae. We observed that the temperature sensitivity, salt tolerance, cell morphology, and sterility of the Deltamoc1 mutant in S. pombe were recovered by expressing either S. cerevisiae SDS23 or SDS24. We found that deletion of both SDS23 and SDS24 resulted in the production of a large vacuole that was reversed by the expression of S. pombe moc1/sds23. In these ways we found that S. pombe Moc1/Sds23 and S. cerevisiae SDS23p or SDS24p are functional homologs. In addition we found that the Deltasds23 Deltasds24 diploid strain reduces cell separation in forming pseudohyphal-like growth in S. cerevisiae. Thus S. pombe moc1/sds23 and S. cerevisiae SDS23 or SDS24 are interchangeable with each other, but their disruptants are phenotypically dissimilar.     

Mechanisms and significance of bifunctional NK4 in cancer treatment

Based on the background that hepatocyte growth factor (HGF) and c-Met/HGF receptor tyrosine kinase play a definite role in tumor invasion and metastasis, NK4, four-kringles containing intramolecular fragment of HGF, was isolated as a competitive antagonist for the HGF-c-Met system. Independent of its HGF-antagonist action, NK4 inhibited angiogenesis induced by vascular endothelial cell growth factor and basic fibroblast growth factor, as well as HGF, indicating that NK4 is a bifunctional molecule that acts as an HGF-antagonist and angiogenesis inhibitor. Interestingly, kringle domains in distinct types of proteins, e.g., plasminogen, prothrombin, plasminogen activators, apolipoprotein(a), and HGF, share angioinhibitory actions. In experimental models of distinct types of cancers, NK4 protein administration or NK4 gene therapy inhibited tumor invasion, metastasis, and angiogenesis-dependent tumor growth. Cancer treatment with NK4 may prove to suppress malignant tumors to be 'static' in both tumor growth and spreading, as based on biological characteristics of malignant tumors.     

Sparse and wavy hair: a new model for hypoplasia of hair follicle and mammary glands on rat chromosome 17

Mutant animals in the skin and hair have been used to identify important genes in biomedical research. We describe a new mutant rat, sparse and wavy hair (swh), that spontaneously arose in a colony of inbred WTC rats. The mutant phenotype was characterized by sparse and wavy hair, which was most prominent at age 3-4 weeks, and was inherited in an autosomal recessive manner. The swh/swh rats showed impaired gain of body weight, and their hair follicles were reduced both in number and size, associated with hypoplasia of the sebaceous glands and the subcutaneous fat tissue. Female swh/swh rats were unable to suckle their offspring. Their mammary glands were hypoplastic, and differentiation of mammary epithelial and myoepithelial cells was impaired. Linkage analysis of 579 backcross rats localized the swh locus to a .35-cM region between D17Rat131 and D17Rat50 in the distal end of rat Chr 17. The swh locus spanned the 3.7-Mb genomic region where 24 genes have been mapped and corresponded to the centromere region of the mouse Chr 2 or the region of the human Chr 10p11.1-p14. None of the genes or loci described in mouse or human hair and skin diseases mapped to these regions. These findings suggest that the rat swh is a novel mutation associated with impaired development of the skin appendages, such as hair follicles, sebaceous glands, and mammary glands, and will provide an experimental model to clarify a gene and mechanisms for development of skin appendages.     

Electro-transfer of small interfering RNA ameliorated arthritis in rats

RNA interference provides the powerful means of sequence-specific gene silencing. Particularly, small interfering RNA (siRNA) duplexes may be potentially useful for therapeutic molecular targeting of human diseases, although novel delivery systems should be devised to achieve efficient and organ-specific transduction of siRNA. In the present study, we demonstrated that electro-transfer of a siRNA-polyamine complex made efficient and specific gene knockdown possible in the articular synovium. Targeted suppression of the tumor necrosis factor-alpha gene through this procedure significantly ameliorated collagen-induced arthritis in rats. Our results suggest the potential feasibility of therapeutic intervention with RNA medicines for treatment of rheumatoid and other locomotor diseases.     

Association test algorithm between a qualitative phenotype and a haplotype or haplotype set using simultaneous estimation of haplotype frequencies, diplotype configurations and diplotype-based penetrances

Analysis of the association between haplotypes and phenotypes is becoming increasingly important. We have devised an expectation-maximization (EM)-based algorithm to test the association between a phenotype and a haplotype or a haplotype set and to estimate diplotype-based penetrance using individual genotype and phenotype data from cohort studies and clinical trials. The algorithm estimates, in addition to haplotype frequencies, penetrances for subjects with a given haplotype and those without it (dominant mode). Relative risk can thus also be estimated. In the dominant mode, the maximum likelihood under the assumption of no association between the phenotype and presence of the haplotype (L(0max)) and the maximum likelihood under the assumption of association (L(max)) were calculated. The statistic -2 log(L(0max)/L(max)) was used to test the association. The present algorithm along with the analyses in recessive and genotype modes was implemented in the computer program PENHAPLO. Results of analysis of simulated data indicated that the test had considerable power under certain conditions. Analyses of two real data sets from cohort studies, one concerning the MTHFR gene and the other the NAT2 gene, revealed significant associations between the presence of haplotypes and occurrence of side effects. Our algorithm may be especially useful for analyzing data concerning the association between genetic information and individual responses to drugs.     

Bi-directional regulation of Ser-985 phosphorylation of c-met via protein kinase C and protein phosphatase 2A involves c-Met activation and cellular responsiveness to hepatocyte growth factor

Previous studies indicated that treatment of cells with 12-O-tetradecanoylphorbol-13-acetate induced phosphorylation of Ser-985 at the juxtamembrane of c-Met, the receptor tyrosine kinase for hepatocyte growth factor (HGF), and this was associated with decreased tyrosine phosphorylation of c-Met. However, the regulatory mechanisms and the biological significance of the Ser-985 phosphorylation in c-Met remain unknown. When A549 human lung cancer cells were exposed to oxidative stress with H(2)O(2), H(2)O(2) treatment induced phosphorylation of Ser-985, but this was abrogated by an inhibitor for protein kinase C (PKC). Likewise, treatment of cells with NaF (an inhibitor of protein phosphatases) allowed for phosphorylation of Ser-985, and a protein phosphatase responsible for dephosphorylation of Ser-985 was identified to be protein phosphatase 2A (PP2A). The effects of PKC inhibitors revealed that PKCdelta and -epsilon were responsible for the Ser-985 phosphorylation of c-Met, and pull-down analysis indicated that associations of PKCdelta and -epsilon with c-Met may be involved in the regulation of Ser-985 phosphorylation of c-Met. Instead, PP2A was constitutively associated with c-Met, whereas its activity to dephosphorylate Ser-985 of c-Met was decreased when cells were exposed to H(2)O(2). Addition of HGF to A549 cells in culture induced c-Met tyrosine phosphorylation, the result being mitogenic response and cell scattering. In contrast, in the presence of H(2)O(2) stress, HGF-dependent tyrosine phosphorylation of c-Met was largely suppressed with a reciprocal relationship to Ser-985 phosphorylation, and this event was associated with abrogation of cellular responsiveness to HGF. These results indicate that Ser-985 phosphorylation of c-Met is bi-directionally regulated through PKC and PP2A, and the Ser-985 phosphorylation status may provide a unique mechanism that confers cellular responsiveness/unresponsivenss to HGF, depending on extracellular conditions.     

Cryopreservation of porcine embryos derived from in vitro-matured oocytes

This study describes a cryopreservation method for porcine in vitro-produced (IVP) embryos using as a model parthenogenetic embryos derived from in vitro-matured (IVM) oocytes. IVP embryos at the expanded blastocyst stage were cryopreserved by vitrification using the minimum volume cooling (MVC) method and exhibited an embryo survival rate of 41.2%. Survival was then significantly improved (83.3%, P < 0.05) by decreasing the amount of cytoplasmic lipid droplets (delipation) prior to vitrification. IVP embryos at the 4-cell stage also survived cryopreservation when vitrified after delipation (survival rate, 36.0%), whereas post-thaw survival of nondelipated embryos was quite low (9.7%). Furthermore, it was demonstrated that porcine IVP morulae can be cryopreserved by vitrification following delipation by a noninvasive method (survival rate, 82.5%). These results clearly confirm that porcine embryos derived from IVM oocytes can be effectively cryopreserved with high embryo survival using the MVC method in conjunction with delipation.     

No influence of tumor growth by intramuscular injection of hepatocyte growth factor plasmid DNA: safety evaluation of therapeutic angiogenesis gene therapy in mice

Recently, a novel therapeutic treatment for ischemic diseases using angiogenic growth factors to augment collateral artery development has been proposed. As intramuscular injection of naked human hepatocyte growth factor (HGF) plasmid DNA induced therapeutic angiogenesis in several animal test subjects, we have started a clinical trial to treat peripheral arterial disease. However, one might assume that over-expression of angiogenic growth factors could enhance tumor growth. To resolve this issue, we examined the over-expression of HGF in tumor bearing mice. Tumors on their backs were prepared with an intradermal inoculation of A431, human epidermoid cancer cells expressing c-Met. These mice were intramuscularly injected with human HGF plasmid or control plasmid into the femoral muscle. Human HGF concentration was increased only in the femoral muscle, but not in blood. Although recombinant HGF stimulated the growth of A431 cells in vitro, temporally and locally HGF elevation in hindlimb had no effect on tumor growth in mice.