Ushio Fukushima

Evaluation of immunological status in tumor-bearing dogs.

The purpose of this study was to evaluate immunological status in dogs with cancers at different stages, in comparison with normal dogs. The population of canine peripheral blood lymphocytes (cPBL), lymphocyte phenotypes, interleukin (IL)-6 activity and alpha 1-acid glycoprotein (alpha(1)-AG) level were analyzed. The tumor-bearing dogs had higher numbers of leukocytes than normal dogs, the count being higher in dogs with more advanced tumors. In the tumor-bearing dogs, differential leukocyte counts revealed higher percentages of inflammatory cells such as neutrophils, acidophils and monocytes, and lower numbers of CD4(+)T cells, than in normal dogs, the lymphocyte counts becoming much lower with tumor progression. In the tumor-bearing dogs, the CD8(+)T cell count at the early tumor stage was similar to that in normal dogs, but decreased with tumor progression, possibly reflecting the development of humoral immunity (Th2). Plasma IL-6 and TGF-beta activities were high in the tumor-bearing dogs. The plasma alpha(1)-AG concentration was also significantly high in the tumor-bearing dogs. Our findings suggest that assay of IL-6, TGF-beta and alpha(1)-AG may be very useful for prognostication in dogs with cancer, and that anti-tumor immunity is potently suppressed in such dogs.

Expression of survivin mRNA in dog tumors

Survivin, a member of the inhibitor of apoptosis (IAP) gene family, overexpresses in various human tumors. Recently this protein has attracted strong interest as a potential prognostic marker because it promotes malignancy through anti-apoptotic activity and is associated with a more aggressive phenotype. To explore the utility of survivin as a veterinary marker of tumor malignancy, we performed molecular cloning of dog survivin cDNA and studied survivin mRNA expression in a variety of naturally occurring dog tumors. The dog cDNA contains a 426-bp open reading frame encoding 142 amino acids of polypeptide, in which a structure termed the baculovirus IAP repeat (BIR) domain, commonly observed in IAPs, is found, as it is in other mammalian survivin protein. The transcript was detected in many adult normal organs including heart, lung, liver, stomach, duodenum, colon, spleen, kidney and testis. As a result of quantitative expression analysis by real-time PCR undertaken for benign and malignant tumors, overexpression of the survivin gene was found in 3 of 18 malignant tumors and in none of the benign tumors, suggesting that survivin overexpression is associated with tumor malignancy in dog.

cDNA cloning of hamster angiotensin-converting enzyme and mRNA expression

Angiotensin-converting enzyme (ACE; EC 3.4.15.1), a dipeptidyl carboxypeptidase, converts angiotensin I to angiotensin II, the central product of the renin–angiotensin system. We here report molecular cloning of the complete open reading frame (ORF) of hamster somatic-type ACE and its expression in hamster organs. The cloned cDNA comprises an ORF of 3942 bp, which encodes 1314 amino acids of the precursor protein of hamster somatic ACE. On the deduced amino acid sequence a putative signal peptide and a transmembrane segment are predicted at the N-terminus and near the C-terminus, respectively. Two homologous domains, referred to as N- and C-domains, are present within somatic ACE, and within each of the homologous domains a putative active center is found, as has been the case in human, mouse, rat and rabbit. The similarity of the hamster sequence with the sequences of these other mammals at both the nucleotide and amino acid levels is high (above 83%). mRNA expression analysis by conventional polymerase chain reaction (PCR) shows wide distribution of the transcript, with dominant expression in lung and kidney. Quantitative analysis of mRNA expression demonstrates that levels in lung and kidney are 100–1000 times higher than in the other organs, suggesting that these organs are important in the hamster renin–angiotensin system, as they are for other mammals.