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Complementary DNAs coding for two subunits of hamster interleukin-12 (IL-12), p35 and p40, were cloned from a hamster dendritic cell (DC) cDNA library. The cloning demonstrated that hamster IL-12 consisted of a p35 subunit with 216 amino acid (aa) residues and a p40 subunit with 327 aa. Structural comparison of hamster p35 and p40 at the protein level showed the highest homologies with each counterpart of sigmodon (hispid cotton rat). The gene expressions of hamster IL-12 p35 and p40 in bone marrow (BM) cells cultured in the presence of mouse granulocyte macrophage-colony-stimulating factor (mGM-CSF) and IL-4 were up-regulated during culture. Immunoblot analysis of 293 cells transfected with hamster p35 and p40 expression vectors suggested the presence of a covalently linked p35/p40 heterodimer. Furthermore, supernatant from the 293 cells transfected with both expression vectors induced the up-regulation of interferon-gamma (IFN-gamma) mRNA in hamster splenocytes, indicating that the p35/p40 heterodimer IL-12 protein present in the supernatant was functional. These results suggest that the vectors containing hamster IL-12 cDNA might be suitable tools for developing an immunotherapeutic approach against experimental cancer in a hamster model.

Ghrelin is a novel brain-gut peptide that stimulates food intake and body weight gain. We studied the anabolic effect of ghrelin in a cancer cachexia mouse model. SEKI, a human melanoma cell line, was inoculated into nude mice to examine the effects of ghrelin on food intake and body weight. The intraperitoneal administration of ghrelin twice a day (6 nmol/mice/day) for 6 days suppressed weight loss in SEKI-inoculated mice and increased the rate of weight gain in vehicle-treated nude mice. Ghrelin administration also increased food intake in both SEKI- and vehicle-treated mice. Both the weight of white adipose tissue and the plasma leptin concentration were reduced in tumor-inoculated mice compared with vehicle-treated mice; these factors increased following ghrelin administration. The levels of both ghrelin peptide and mRNA in the stomach were upregulated in tumor-inoculated mice. The anabolic effect of ghrelin efficiently reverses the cachexia in mice bearing SEKI human melanoma. Ghrelin therefore may have a therapeutic ability to ameliorate cancer cachexia.

DEC-205, a putative antigen uptake receptor, belongs to a family of transmembrane C-type lectins. This molecule is known to be one of the most authentic markers for the lineage of dendritic cells. In the present study, we determined the primary structure, tissue distribution and cellular localization of hamster DEC-205. The multi-domain structure of mouse and human DEC-205 was completely conserved in hamster with the overall identity of approximately 80%. DEC-205 transcripts were detected in the thymus and bone marrow cells cultured in the presence of mouse granulocyte macrophage colony-stimulating factor and interleukin-4 in which the DEC-205 expression was up-regulated in the course of cultures. Hamster DEC-205 was mainly detected on cell membrane and shown to mediate the uptake of flourescein isothiocyanate-conjugated ovalbumin. DEC-205 is a highly conserved molecule across the species suggesting its fundamental role in the immune system.

Previous studies have shown that five human cancer cell lines, LS180, MKN-1, MMG-1, C32 and LX-1, induced remarkable weight loss in tumor-bearing nude mice. With the aim of identifying novel molecules involved in lipid catabolism, conditioned media of these cancer cell lines were analyzed in terms of lipoprotein lipase (LPL)-inhibiting or lipolytic activities. All conditioned media from the five cell lines significantly suppressed LPL activity in 3T3-L1 cells, while media from LX-1 and C32 promoted lipolytic activity in a dose-dependent manner. RT-PCR and ELISA demonstrated that the major factors responsible for LPL inhibition and lipolysis were not IL-1beta, IL-6, IL-11, TNF-alpha, TGF-beta1 or LIF in all the cancer cell lines except for MMG-1 cells. Preliminary biochemical analysis showed that the LPL-inhibiting factor produced by LX-1 cells was approximately 65 kD and vulnerable to heat, whereas the lipolytic factor was less than 1 kD and heat stable. These results suggested that unknown factors are partially involved in the pathogenesis of cancer cachexia in tumor-bearing nude mice and further purification will be needed.

MUC1 protein is widely expressed on various human cancer cells and has a specific highly glycosylated core structure with multiple tandem repeats, which may include an immunogenic peptide sequence. The potency of MUC1 protein to induce human histocompatibility leukocyte antigen-class I-restricted cytotoxic T-lymphocyte (CTL) induction remains to be fully clarified in human beings. In the current study, we made MUC1-expressing human dendritic cells (DCs) using recombinant adenovirus vector. Adenovirus vector plasmid containing human MUC1 cDNA, pAdHM4-MUC1 was constructed using in vitro ligation with a shuttle vector, pHMCMV5. Adenovirus vector expressing MUC1 was generated by the transfection of PacI-digested recombinant vector plasmid into 293 cells. Human blood DCs were obtained from 7-day culture of monocytes with recombinant human (rh) granulocyte-macrophage (GM) colony-stimulating factor (CSF) and (rh)interleukin (IL)-4. Then, 1 x 10(6) DCs were incubated with viral supernatant at a multiplicity of infection of 200 for 24 h in the presence of rhGM-CSF and rhIL-4. Flow cytometric analysis showed that 30% to 40% of the transduced DCs expressed MUC I protein; by contrast, nontransduced or transduced DCs with mock virus expressed only small amounts of MUC1 protein. Adenovirus-mediated MUC1 gene transduction into DCs had no significant effect on DC surface marker expressions or functions such as mixed leukocyte reaction. Furthermore, MUCI-specific CD8+ CTLs could be induced from healthy donor blood lymphocytes using MUC1-expressing DCs as stimulators. These results suggested that MUC1 gene-transduced DCs are a functional and potent tool for triggering a CTL response against MUC1 cancer cells.

We selected three human cancer cell lines [human melanoma (SEKI), human melanoma (G361), and human neuroepithelioma (NAGAI)] that have an ability to develop cancer cachexia syndrome with and without accompanying anorexia and examined the hypothalamic levels of mRNAs for neuropeptide Y (NPY), melanin-concentrating hormone, and orexin. The body weight of sham-operated mice continued to increase, while mice of all tumor-bearing groups lost weight. Competitive reverse transcription-polymerase chain reaction analysis showed that, regardless of feeding status, NPY mRNA levels were elevated in all tumor-bearing mice compared with sham-operated mice, although to a lesser degree than weight-matched pair-weight mice. Melanin-concentrating hormone and orexin mRNA in the hypothalamus followed the same pattern as NPY, although most of the differences did not reach statistical significance. These results support the notion that the response of NPY mRNA to a negative energy balance is less sensitive in these rodent models of cancer cachexia.