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[Background] The inflammatory response in Helicobacter pylori-infected gastric tissue is mediated by cag pathogenicity island (PAI)-dependent activation of nuclear factor-κB (NF-κB). Phosphatidylinositol 3-kinase (PI3K)/Akt signaling is known to play a role in NF-κB activation, but little information is available on the relationship between H. pylori and PI3K/Akt signaling in gastric epithelial cells. We examined whether H. pylori activates Akt in gastric epithelial cells, the role of cag PAI in this process and the role of Akt in regulating H. pylori-induced NF-κB activation., [Results] Phosphorylated Akt was detected in epithelial cells of H. pylori-positive gastric tissues. Although Akt was activated in MKN45 and AGS cells by coculture with cag PAI-positive H. pylori strains, a cag PAI-negative mutant showed no activation of Akt. H. pylori also induced p65 phosphorylation. PI3K inhibitor suppressed H. pylori-induced p65 phosphorylation and NF-κB transactivation, as well as interleukin-8 expression. Furthermore, transfection with a dominant-negative Akt inhibited H. pylori-induced NF-κB transactivation. Transfection with small interference RNAs for p65 and Akt also inhibited H. pylori-induced interleukin-8 expression., [Conclusion] The results suggest that cag PAI-positive H. pylori activates Akt in gastric epithelial cells and this may contribute to H. pylori-mediated NF-κB activation associated with mucosal inflammation and carcinogenesis.

本研究は，温浴時の海水濃度条件の違いが体温変動，心拍数および主観的温度感覚に及ばす影響を検討するために，38．5℃に設定された水温条件下で15分間入浴および60分間安静の温浴実験をおこなった。海水濃度条件は0％，1％，3．5％，7％の4種類とした。被験者は年齢18～21歳の健康な男子大学生8名であった。被験者の平均の年齢，身長，体重および体脂肪率はそれぞれ19．8±1．0歳，169．2±5．Ocm，57．1±3．1kgおよび14．0±2．6％であった。直腸温は，全条件とも入浴直後から一過性に上昇傾向を示し，出浴後は潜熱現象を示した。海水濃度を比較すると，7＞3．5＞1＞0％の順に有意な上昇傾向を示した。平均皮膚温は，全条件とも入浴直後から10分間は一過性に上昇傾向を示した。その後，入浴10～20分の間はわずかに上昇し，出浴後は10分前後に急速に下降傾向を示し，それ以降はゆるやかな低下を示した。海水濃度を比較すると，7％膿度が他濃度より入浴時の上昇度が高く，またその影響で出浴後の温度低下度も他濃度より低い傾向を示した。平均体温は，全条件とも入浴直後から一過性に上昇傾向を，また出浴直後から急速に下降傾向を示し，その後の回復期にはゆるやかな低下を示した。以上の結果から7％までの海水濃度温浴では，直腸温および皮膚温ともに成分濃度依存性の体温上昇反応が示唆された。, The purpose of the present study was to compare thermal responses of the body between bathing in warm sea water and further to examine effects of concentration of chemical components in sea water affect thermal responses of the body when bathing in warm sea water. The thermal responses were based on the examination of taking rectal, skin, and mean body temperatures in bathing and recovery on land. Eight healthy men were the subjects in this experiment, and they were in average 19.8±1.0 in age, 169.2±5.0cms in height, 57.1±3.1kgs in weight, and 14.0±2.6% in fat. The subjects bathed in sea water and fresh water for 15 minutes and took recovery on land for 60 minutes respectively. The experiment was tested under water temperature at 38.5℃ during bathing. The conditions of concentration of chemical components in sea water were 7, 3.5, 1, 0%. For all the subjects, the rectal temperature increased during bathing and decreased gradually during recovery on land. Bathing in sea water statistically showed significant increases of rectal temperature at 15 minutes during bathing. It was constantly higher at 7> 3.5 > 1 > 0%. The mean skin temperature showed a continuous increase during bathing and showed a rapid decrease during 5 minutes in recovery on land, and a gradual decrease after then. No statistically significant differences were detected in the mean skin temperature between 7, 3.5, 1 and 0%. The mean body temperature also showed a continuous increase during bathing and showed a rapid decrease during the 10 minutes in recovery on land, and a gradual decrease after then. In bathing in sea water the mean body temperature statistically showed significant increases during bathing.

[Background] Human T-cell leukemia virus type I (HTLV-I) is associated with pulmonary diseases, characterized by bronchoalveolar lymphocytosis, which correlates with HTLV-I proviral DNA in carriers. HTLV-I Tax seems to be involved in the development of such pulmonary diseases through the local production of inflammatory cytokines and chemokines in T cells. However, little is known about induction of these genes by HTLV-I infection in lung epithelial cells., [Results] We tested infection of lung epithelial cells by HTLV-I by coculture studies in which A549 alveolar and NCI-H292 tracheal epithelial cell lines were cocultured with MT-2, an HTLV-I-infected T-cell line. Changes in the expression of several cellular genes were assessed by reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay and flow cytometry. Coculture with MT-2 cells resulted in infection of lung epithelial cells as confirmed by detection of proviral DNA, HTLV-I Tax expression and HTLV-I p19 in the latter cells. Infection was associated with induction of mRNA expression of various cytokines, chemokines and cell adhesion molecule. NF-κB and AP-1 were also activated in HTLV-I-infected lung epithelial cells. In vivo studies showed Tax protein in lung epithelial cells of mice bearing Tax and patients with HTLV-I-related pulmonary diseases., [Conclusion] Our results suggest that HTLV-I infects lung epithelial cells, with subsequent production of cytokines, chemokines and cell adhesion molecules through induction of NF-κB and AP-1. These changes can contribute to the clinical features of HTLV-I-related pulmonary diseases.

Clinical trials for treatment of adult T-cell leukemia (ATL) caused by human T-cell leukemia virus type I (HTLV-I) using all-trans-retinoic acid (ATRA) have shown satisfactory therapeutic responses, although efficacies were limited. Recently, many synthetic retinoids have been developed and among them, a novel synthetic retinoid, Am80 (Tamibarotene) is an RARα- and RARβ-specific retinoid expected to overcome ATRA resistance. The present study examined the inhibitory effects of Am80 on HTLV-I-infected T-cell lines and ATL cells. Am80 had negligible growth inhibition of peripheral blood mononuclear cells but marked growth inhibition of both HTLV-I-infected T-cell lines and ATL cells. Am80 arrested cells in the G1 phase of the cell cycle and induced apoptosis in HTLV-I-infected T-cell lines. It inhibited also the phosphorylation of IκBα and NF-κB-DNA binding, in conjunction with reduction of expression of proteins involved in the G1/S cell cycle transition and apoptosis. Am80 also inhibited the expression of JunD, resulting in suppression of AP-1-DNA binding. Furthermore, severe combined immunodeficient mice with tumors induced by subcutaneous inoculation of HTLV-I-infected T cells, responded to Am80 treatment with partial regression of tumors and no side-effects. These findings demonstrate that Am80 is a potential inhibitor of NF-κB and AP-1, and is a potentially useful therapeutic agent against ATL. (Cancer Sci 2008; 99: 2286–2294)

Clinical trials for treatment of adult T-cell leukemia (ATL) caused by human T-cell leukemia virus type I (HTLV-I) using all-trans-retinoic acid (ATRA) have shown satisfactory therapeutic responses, although efficacies were limited. Recently, many synthetic retinoids have been developed and among them, a novel synthetic retinoid, Am80 (Tamibarotene) is an RARα- and RARβ-specific retinoid expected to overcome ATRA resistance. The present study examined the inhibitory effects of Am80 on HTLV-I-infected T-cell lines and ATL cells. Am80 had negligible growth inhibition of peripheral blood mononuclear cells but marked growth inhibition of both HTLV-I-infected T-cell lines and ATL cells. Am80 arrested cells in the G1 phase of the cell cycle and induced apoptosis in HTLV-I-infected T-cell lines. It inhibited also the phosphorylation of IκBα and NF-κB-DNA binding, in conjunction with reduction of expression of proteins involved in the G1/S cell cycle transition and apoptosis. Am80 also inhibited the expression of JunD, resulting in suppression of AP-1-DNA binding. Furthermore, severe combined immunodeficient mice with tumors induced by subcutaneous inoculation of HTLV-I-infected T cells, responded to Am80 treatment with partial regression of tumors and no side-effects. These findings demonstrate that Am80 is a potential inhibitor of NF-κB and AP-1, and is a potentially useful therapeutic agent against ATL. (Cancer Sci 2008; 99: 2286–2294)

Anti-resorptive bisphosphonates are used for the treatment of hypercalcemia and bone complications associated with malignancies and osteoporosis, but have also been shown to have anti-tumour effects in various cancers. Adult T-cell leukaemia (ATL) is a fatal T-cell malignancy caused by infection with human T-cell leukaemia virus type I (HTLV-I), and remains incurable. ATL is associated with osteolytic bone lesions and hypercalcemia, which are major factors in the morbidity of ATL. Thus, the search for anti-ATL agents that have both anti-tumour and anti-resorptive activity is warranted. The bisphosphonate agent, incadronate prevented cell growth of HTLV-I-infected T-cell lines and primary ATL cells, but not of non-infected T-cell lines or normal peripheral blood mononuclear cells. Incadronate induced S-phase cell cycle arrest and apoptosis in HTLV-I-infected T-cell lines, and treatment of these cells with substrates of the mevalonate pathway blocked the incadronate-mediated growth suppression. Incadronate also prevented the prenylation of Rap1A protein. These results demonstrated that incadronate-induced growth suppression occurs by interfering with the mevalonate pathway. Importantly, treatment with incadronate reduced tumour formation from an HTLV-I-infected T-cell line, when these cells were inoculated subcutaneously into severe combined immunodeficient mice. These findings suggest that incadronate could be potentially useful for the treatment of ATL.

ATL is a fatal malignancy of T lymphocytes caused by HTLV-I infection and remains incurable. Galectins are a family of animal lectins that function both extracellularly (by interacting with cell surface and extracellular matrix glycoproteins and glycolipids) and intracellularly (by interacting with cytoplasmic and nuclear proteins) to modulate signaling pathways. We found that protease-resistant galectin-9 by modification of its linker peptide, hG9NC(null), prevented cell growth of HTLV-I-infected T-cell lines and primary ATL cells. The suppression of cell growth was inhibited by lactose, but not by sucrose, indicating that β-galactoside binding is essential for hG9NC(null)-induced cell growth suppression. hG9NC(null) induced cell cycle arrest by reducing the expression of cyclin D1, cyclin D2, cyclin B1, Cdk1, Cdk4, Cdk6, Cdc25C and c-Myc, and apoptosis by reducing the expression of XIAP, c-IAP2 and survivin. Most of these genes are regulated by NF-κB, which plays a critical role in oncogenesis by HTLV-I. hG9NC(null) suppressed IκBα phosphorylation, resulting in suppression of NF-κB. Most importantly, treatment with hG9NC(null) (6.7 mg/kg injected intraperitoneally every day) reduced tumor formation from an HTLV-I-infected T-cell line when these cells were inoculated subcutaneously into SCID mice. Our results suggest that hG9NC(null) could be a suitable agent for the management of ATL.

Citrin is a mitochondrial aspartate glutamate carrier primarily expressed in liver. Adult-onset type II citrullinemia is caused by mutations in the SLC25A13 gene that encodes for citrin, and patients with this condition do not express citrin. We found apoptotic hepatocytes in one such patient. This finding prompted us to investigate the role of citrin in hepatocyte survival. Knockdown of citrin by a vector-based short-hairpin RNA technique reduced cell viability and induced apoptosis of a hepatocellular carcinoma cell line, Hep3B cells. Caspase-3/7 and caspase-9 were activated, and PARP was cleaved. Citrin knockdown also increased the expression of Bax and Bak, and reduced expression of Bcl-xL and Bcl-2. These alterations resulted in the release of cytochrome c from the mitochondria. Our results indicated that citrin downregulation induces apoptosis of hepatocytes through the mitochondrial death pathway, highlighting the importance of citrin in survival of hepatocytes and maintenance of liver function.

The molecular chaperone Hsp90 is involved in the stabilization and conformational maturation of many signaling proteins that are deregulated in cancers. The geldanamycin derivative 17-AAG is currently tested in clinical trials and known to inhibit the function of Hsp90 and promote the proteasomal degradation of its misfolded client proteins. ATL is a fatal malignancy of T lymphocytes caused by HTLV-I infection and remains incurable. Since Hsp90 is overexpressed in HTLV-I-infected T-cell lines and primary ATL cells, we analyzed the effects of 17-AAG on cell survival, apoptosis and expression of signal transduction proteins. HTLV-I-infected T-cell lines and primary ATL cells were significantly more sensitive to 17-AAG in cell survival assays than normal PBMCs. 17-AAG induced the inhibition of cell cycle and apoptosis. These effects could be mediated by inactivation of NF-B, AP-1 and PI3K/Akt pathways, as well as reduction of expression of proteins involved in the G1-S cell cycle transition and apoptosis. Proteasome inhibition interfered with 17-AAG-mediated signaling proteins depletion. Collectively, our results indicate that 17-AAG suppresses ATL cell survival through, at least in part, destabilization of several client proteins and suggest that 17-AAG is a potentially useful chemotherapeutic agent for ATL.