Evaluation of two prognostic indices for adult T-cell leukemia/lymphoma in the subtropical endemic area, Okinawa, Japan.

Aggressive adult T-cell leukemia/lymphoma (ATL) has an extremely poor prognosis and is hyperendemic in Okinawa, Japan. This study evaluated two prognostic indices (PIs) for aggressive ATL, the ATL-PI and Japan Clinical Oncology Group (JCOG)-PI, in a cohort from Okinawa. The PIs were originally developed using two different Japanese cohorts that included few patients from Okinawa. The endpoint was overall survival (OS). Multivariable Cox regression analyses in the cohort of 433 patients revealed that all seven factors for calculating each PI were statistically significant prognostic predictors. Three-year OS rates for ATL-PI were 35.9% (low-risk, n = 66), 10.4% (intermediate-risk, n = 256), and 1.6% (high-risk, n = 111), and those for JCOG-PI were 22.4% (moderate-risk, n = 176) and 5.3% (high-risk, n = 257). The JCOG-PI moderate-risk group included both the ATL-PI low- and intermediate-risk groups. ATL-PI more clearly identified the low-risk patient subgroup than JCOG-PI. To evaluate the external validity of the two PIs, we also assessed prognostic discriminability among 159 patients who loosely met the eligibility criteria of a previous clinical trial. Three-year OS rates for ATL-PI were 34.5% (low-risk, n = 42), 9.2% (intermediate-risk, n = 109), and 12.5% (high-risk, n = 8). Those for JCOG-PI were 22.4% (moderate-risk, n = 95) and 7.6% (high-risk, n = 64). The low-risk ATL-PI group had a better prognosis than the JCOG-PI moderate-risk group, suggesting that ATL-PI would be more useful than JCOG-PI for establishing and examining novel treatment strategies for ATL patients with a better prognosis. In addition, strongyloidiasis, previously suggested to be associated with ATL-related deaths in Okinawa, was not a prognostic factor in this study.

Human T-cell leukemia virus type I Tax genotype analysis in Okinawa, the southernmost and remotest islands of Japan: Different distributions compared with mainland Japan and the potential value for the prognosis of aggressive adult T-cell leukemia/lymphoma.

Okinawa, comprising remote islands off the mainland of Japan, is an endemic area of human T-cell leukemia virus type I (HTLV-1), the causative virus of adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy (HAM). We investigated the tax genotype of HTLV-1 among 29 HTLV-1 carriers, 74 ATL patients, and 33 HAM patients in Okinawa. The genotype distribution-60 (44%) taxA cases and 76 (56%) taxB cases-differed from that of a previous report from Kagoshima Prefecture in mainland Japan (taxA, 10%; taxB, 90%). A comparison of the clinical outcomes of 45 patients (taxA, 14; taxB, 31) with aggressive ATL revealed that the overall response and 1-year overall survival rates for taxA (50% and 35%, respectively) were lower than those for taxB (71% and 49%, respectively). In a multivariate analysis of two prognostic indices for aggressive ATL, Japan Clinical Oncology Group-Prognostic Index and Prognostic Index for acute and lymphoma ATL, with respect to age, performance status, corrected calcium, soluble interleukin-2 receptor, and tax genotype, the estimated hazard ratio of taxA compared with taxB was 2.68 (95% confidence interval, 0.87-8.25; P=0.086). Our results suggest that the tax genotype has clinical value as a prognostic factor for aggressive ATL.

Characterization of patients with aggressive adult T-cell leukemia-lymphoma in Okinawa, Japan: a retrospective analysis of a large cohort.

Okinawa Prefecture, located in the subtropics, is an area of endemic adult T-cell leukemia-lymphoma (ATL) in Japan. We retrospectively analyzed 659 patients with aggressive ATL in seven institutions in Okinawa between 2002 and 2011. The median patient age was 68 years. More patients were aged ≥90 years (2.6 %), in this study, than in a nationwide survey (<1 %). The median survival time (MST) of the entire cohort was 6.5 months. Of the 217 patients who had a clinical status similar to that stated in the eligibility criteria of JCOG9801 (a randomized phase III study comparing VCAP-AMP-VECP with CHOP-14), 147 who received the CHOP regimen had a poorer MST than those in the CHOP-14 arm of JCOG9801 (8 vs 11 months). The prevalence of strongyloidiasis in the ATL patients was much higher (12.4 %) than in the historical cohort who visited the University of the Ryukyus Hospital (3.4 %). Furthermore, strongyloidiasis may be associated with ATL-related deaths. These findings suggest that, compared with other areas in Japan, in Okinawa, the proportion of patients aged ≥90 years with clinical features of aggressive ATL is higher, outcomes are poorer, and the disease is associated with a higher prevalence of strongyloidiasis.

Protein phosphatase 2A as a potential target for treatment of adult T cell leukemia.

The aim of this study was to establish the role of serine/threonine protein phosphatase 2A (PP2A) in the survival of leukemic cells from patients with adult T cell leukemia (ATL), associated with human T cell leukemia virus type 1 (HTLV-1). In HTLV-1-infected T cell lines and ATL cells, okadaic acid (OkA), a potent PP2A inhibitor, induced decrease in cell viability and G1 cell cycle arrest by decreasing the expression levels of cyclin D2, cyclin-dependent kinase 4 and cyclin-dependent kinase 6, phosphorylation of pRb, and upregulation of p21, p27 and GADD45α. OkA-induced apoptosis was also due to the suppression of expression of Bcl-2, Bcl-x(L) and XIAP, and the activation of caspases-3, -8 and -9, and caspase-3 downstream mammalian STE20-like kinase 1 and H2AX. OkA inhibited nuclear factor-kappa B DNA binding and activated mitogen-activated protein (MAP) kinases. Other new PP2A-specific inhibitors, cytostatin and rubratoxin A, also induced decrease in cell viability through caspase-dependent mechanism. MAP kinase inhibitors confirmed the role of p38 MAP kinase in PP2A inhibitors-induced apoptosis. OkA resulted in the generation of reactive oxygen species, and exogenous antioxidant prevented activation of the indicated caspases. Finally, PP2A knockdown inhibited cell growth. The results showed that PP2A inhibition caused reactive oxygen species generation and affected distinct signaling pathways, resulting in the activation of H2AX and subsequent apoptotic cell death. These results suggest that PP2A is a potentially useful target in the treatment of ATL.

[The appearance of t(9;22)(q34;q11.2) in BJP-λ type multiple myeloma during maintenance therapy including lenalidomide].

A 61-year-old man, who was diagnosed with Bence-Jones protein (BJP)-λ type multiple myeloma, was treated with bortezomib. Although maintenance therapy including lenalidomide was continued, t(9;22)(q34;q11.2) was detected in the marrow cells by a cytogenetic study. The increased incidence of a secondary malignancy after treatment with lenalidomide for multiple myeloma has been highlighted in previous clinical trials; however, reports on the presence of t(9;22)(q34;q11.2) or the onset of chronic myelogenous leukemia have yet to be found. Although the cause of chronic myelogenous leukemia with the lenalidomide treatment is not yet clear, it is an interesting case.

CD69 overexpression by human T-cell leukemia virus type 1 Tax transactivation.

Human T-cell leukemia virus type 1 (HTLV-1) infection is associated with the development of adult T-cell leukemia (ATL) and various inflammatory diseases. CD69 is a marker of early activation of lymphocytes. We investigated the effects of HTLV-1 infection on the expression of CD69. The CD69 gene was upregulated in all viral protein Tax-expressing HTLV-1-transformed T-cell lines, except MT-2 and peripheral blood mononuclear cells from patients with ATL compared with uninfected T-cell line, Tax-negative ATL-derived T-cell lines and normal peripheral blood mononuclear cells. Flow cytometric analysis and immunohistochemical analysis confirmed the enhanced expression of CD69 in HTLV-1-transformed T-cell lines and in ATL cells in lymph nodes and skin lesions, and its absence in MT-2 and peripheral blood mononuclear cells. CD69 expression was induced following infection of human T-cell line with HTLV-1, and specifically by Tax. Tax transcriptionally activated CD69 gene through both nuclear factor-κB and cyclic adenosine 3',5'-monophosphate response element-binding protein signaling pathways. Detailed analysis of the CD69 promoter indicated that the Tax-induced expression of CD69 was regulated by multiple cis-acting elements and by the interplay of transcription factors of the nuclear factor-κB, early growth response and cyclic adenosine 3',5'-monophosphate response element-binding protein families. The lack of CD69 expression in MT-2 is due to epigenetic mechanism involving deacetylation, but not methylation. We conclude that CD69 is a Tax-regulated gene, and its regulation by Tax may play a role in cellular activation and HTLV-1-induced disease pathogenesis.

Overexpression of caveolin-1 in adult T-cell leukemia.

Caveolin-1 is implicated in the regulation of signal pathways. Adult T-cell leukemia (ATL) is a T-cell malignancy causatively associated with human T-cell leukemia virus type 1 (HTLV-1). To determine the role of caveolin-1 in leukemogenesis, we examined caveolin-1 expression levels in HTLV-1-infected T-cell lines and ATL cells. These cells expressed high levels of caveolin-1 compared with uninfected T-cell lines and normal peripheral blood mononuclear cells (PBMCs). Caveolin-1-positive ATL cells were detected in ATL lymph nodes and skin lesions, and caveolin-1 was also detected in the plasma of patients with ATL. Infection of a human T-cell line, an epithelial cell line, and normal PBMCs with HTLV-1 induced caveolin-1 expression. The viral protein Tax transcriptionally activated caveolin-1 gene through nuclear factor-kappaB and cAMP response element binding protein signal pathways. HTLV-1-infected T-cell lines, and ATL cells are known to be resistant to transforming growth factor beta (TGF-beta)-induced growth inhibition. Caveolin-1 was colocalized with TGF-beta type I receptor in HTLV-1-infected T-cell lines and suppressed TGF-beta signaling. Caveolin-1 knockdown in an HTLV-1-infected T-cell line exhibited susceptibility to TGF-beta. Thus, we describe a new function for Tax, repression of TGF-beta signaling through caveolin-1 expression, which may play a critical role in ATL leukemogenesis.

Aberrant expression of the transcription factor Twist in adult T-cell leukemia.

Adult T-cell leukemia (ATL) is a T-cell malignancy etiologically associated with human T-cell leukemia virus type 1 (HTLV-1). Twist, a highly conserved basic helix-loop-helix transcription factor, is a newly identified oncogene. However, there are no reports on Twist expression in ATL. To define the role of Twist in leukemogenesis of ATL, we examined its expression in T-cell lines and PBMC. HTLV-1-infected T-cell lines and ATL cells expressed high levels of Twist compared with uninfected T-cell lines and normal PBMC. Immunohistochemistry showed immunostaining for Twist in ATL cells in ATL lymph nodes and skin lesions. Infection of normal PBMC with HTLV-1 induced Twist expression. Induction of the viral protein Tax in a human T-cell line led to upregulation of Twist. Tax-induced Twist expression involved the NF-kappaB and CREB signaling pathways. Twist augmented Tax-mediated HTLV-1 LTR and NF-kappaB activation. Short interfering RNA against Twist inhibited cell growth of HTLV-1-infected T-cell lines and downregulation of Twist expression in an HTLV-1-infected T-cell line inhibited the expression of Akt1, interleukin-2 receptor alpha chain, and Tax as well as the known target genes of Twist, YB-1 and Akt2. In conclusion, the results suggest that Tax-induced induction of Twist contributes to leukemogenesis of ATL.

Overexpression of Aurora A by loss of CHFR gene expression increases the growth and survival of HTLV-1-infected T cells through enhanced NF-kappaB activity.

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia (ATL). Aurora A, a mitotic checkpoint protein, is overexpressed in human cancer cells. The cell cycle-dependent turnover of Aurora A is regulated by E3 ubiquitin ligases such as checkpoint with fork head-associated and ring finger (CHFR). Here, we found overexpression of Aurora A protein in HTLV-1-infected T-cell lines and primary ATL cells. The expression of CHFR mRNA was reduced in these cells by abnormal methylation of CHFR promoter region. Knockdown of Aurora A using small interfering RNA suppressed the growth of HTLV-1-infected T-cell line. Transfection of Aurora A expression plasmid enhanced Tax-induced nuclear factor-kappaB (NF-kappaB) reporter activity. Transfection of CHFR expression plasmid into an HTLV-1-infected T-cell line reduced cell growth, Aurora A protein level and constitutive NF-kappaB reporter activity. Aurora kinase inhibitor suppressed the growth and survival of HTLV-1-infected T-cell lines and primary ATL cells. It also reduced constitutive NF-kappaB activity in an HTLV-1-infected T-cell line by reducing IkappaB kinase beta phosphorylation and the expression of antiapoptotic protein survivin. Our results suggested that loss of CHFR expression resulted to accumulation of Aurora A, which increased NF-kappaB activity. These findings highlight the critical role of Aurora A in HTLV-1-infected T cells, making this molecule a potentially suitable target for future therapies for ATL.

Anti-adult T-cell leukemia/lymphoma effects of indole-3-carbinol.

BACKGROUND: Adult T-cell leukemia/lymphoma (ATLL) is a malignancy derived from T cells infected with human T-cell leukemia virus type 1 (HTLV-1), and it is known to be resistant to standard anticancer therapies. Indole-3-carbinol (I3C), a naturally occurring component of Brassica vegetables such as cabbage, broccoli and Brussels sprout, is a promising chemopreventive agent as it is reported to possess antimutagenic, antitumorigenic and antiestrogenic properties in experimental studies. The aim of this study was to determine the potential anti-ATLL effects of I3C both in vitro and in vivo. RESULTS: In the in vitro study, I3C inhibited cell viability of HTLV-1-infected T-cell lines and ATLL cells in a dose-dependent manner. Importantly, I3C did not exert any inhibitory effect on uninfected T-cell lines and normal peripheral blood mononuclear cells. I3C prevented the G1/S transition by reducing the expression of cyclin D1, cyclin D2, Cdk4 and Cdk6, and induced apoptosis by reducing the expression of XIAP, survivin and Bcl-2, and by upregulating the expression of Bak. The induced apoptosis was associated with activation of caspase-3, -8 and -9, and poly(ADP-ribose) polymerase cleavage. I3C also suppressed IkappaBalpha phosphorylation and JunD expression, resulting in inactivation of NF-kappaB and AP-1. Inoculation of HTLV-1-infected T cells in mice with severe combined immunodeficiency resulted in tumor growth. The latter was inhibited by treatment with I3C (50 mg/kg/day orally), but not the vehicle control. CONCLUSION: Our preclinical data suggest that I3C could be potentially a useful chemotherapeutic agent for patients with ATLL.

Anti-adult T-cell leukemia effects of a novel synthetic retinoid, Am80 (Tamibarotene).

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 RARalpha- and RARbeta-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 IkappaBalpha and NF-kappaB-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-kappaB and AP-1, and is a potentially useful therapeutic agent against ATL.

Anti-adult T-cell leukemia effects of brown algae fucoxanthin and its deacetylated product, fucoxanthinol.

Adult T-cell leukemia (ATL) is a fatal malignancy of T lymphocytes caused by human T-cell leukemia virus type 1 (HTLV-1) infection and remains incurable. Carotenoids are a family of natural pigments and have several biological functions. Among carotenoids, fucoxanthin is known to have antitumorigenic activity, but the precise mechanism of action is not elucidated. We evaluated the anti-ATL effects of fucoxanthin and its metabolite, fucoxanthinol. Both carotenoids inhibited cell viability of HTLV-1-infected T-cell lines and ATL cells, and fucoxanthinol was approximately twice more potent than fucoxanthin. In contrast, other carotenoids, beta-carotene and astaxanthin, had mild inhibitory effects on HTLV-1-infected T-cell lines. Importantly, uninfected cell lines and normal peripheral blood mononuclear cells were resistant to fucoxanthin and fucoxanthinol. Both carotenoids induced cell cycle arrest during G(1) phase by reducing the expression of cyclin D1, cyclin D2, CDK4 and CDK6, and inducing the expression of GADD45alpha, and induced apoptosis by reducing the expression of Bcl-2, XIAP, cIAP2 and survivin. The induced apoptosis was associated with activation of caspase-3, -8 and -9. Fucoxanthin and fucoxanthinol also suppressed IkappaBalpha phosphorylation and JunD expression, resulting in inactivation of nuclear factor-kappaB and activator protein-1. Mice with severe combined immunodeficiency harboring tumors induced by inoculation of HTLV-1-infected T cells responded to treatment with fucoxanthinol with suppression of tumor growth, showed extensive tissue distribution of fucoxanthinol, and the presence of therapeutically effective serum concentrations of fucoxanthinol. Our preclinical data suggest that fucoxanthin and fucoxanthinol could be potentially useful therapeutic agents for patients with ATL.

Activation of hypoxia-inducible factor 1 in human T-cell leukaemia virus type 1-infected cell lines and primary adult T-cell leukaemia cells.

HTLV-1 (human T-cell leukaemia virus type 1) is the causative agent for ATL (adult T-cell leukaemia). HTLV-1 Tax can activate the PI3K (phosphoinositide 3-kinase)/Akt signalling pathway, which is responsible for survival of HTLV-1-infected T-cells. HIFs (hypoxia-inducible factors) are transcriptional regulators that play a central role in the response to hypoxia. Overexpression of HIF-1alpha in many cancers is associated with a poor response to treatment and increased patient mortality. Our objectives in the present study were to investigate whether HIF-1 was activated in HTLV-1-infected T-cells and to elucidate the molecular mechanisms of HIF-1 activation by focusing on the PI3K/Akt signalling pathway. We detected a potent pathway that activated HIF-1 in the HTLV-1-infected T-cells under a normal oxygen concentration. Enhanced HIF-1alpha protein expression and HIF-1 DNA-binding activity were exhibited in HTLV-1-infected T-cell lines. Knockdown of HIF-1alpha by siRNA (small interfering RNA) suppressed the growth and VEGF (vascular endothelial growth factor) expression of the HTLV-1-infected T-cell line. HIF-1 protein accumulation and transcriptional activity were enhanced by Tax, which was inhibited by dominant-negative Akt. Importantly, mutant forms of Tax that are defective in activation of the PI3K/Akt pathway failed to induce HIF-1 transcriptional activity. The PI3K inhibitor LY294002 suppressed HIF-1alpha protein expression, HIF-1 DNA-binding and HIF-1 transcriptional activity in HTLV-1-infected T-cell lines. In primary ATL cells, HIF-1alpha protein levels were strongly correlated with levels of phosphorylated Akt. The results of the present study suggest that PI3K/Akt activation induced by Tax leads to activation of HIF-1. As HIF-1 plays a major role in tumour progression, it may represent a molecular target for the development of novel ATL therapeutics.

Primary adrenal adult T-cell leukemia/lymphoma: a case report and review of the literature.

Primary adrenal lymphoma (PAL) is very rare; the majority of cases reported previously were of B-cell origin. We report a rare case of primary adrenal adult T-cell leukemia/lymphoma (primary adrenal ATLL). ATLL is a highly aggressive T-cell type non-Hodgkin's lymphoma and etiologically associated with human T-cell lymphotropic virus 1 (HTLV-1). Most ATLL patients present with leukemia and widespread lymphadenopathy. A 37-year-old Japanese woman presented with back pain in January 2004. Examination showed no peripheral lymphadenopathy, circulating lymphoma cells, hepatosplenomegaly, and skin lesions. Imaging studies demonstrated large adrenal masses bilaterally. Subsequently, she underwent open adrenal biopsy and pathological diagnosis was confirmed as T-cell lymphoma. The serum antibody to HTLV-1 was positive. Southern blot analysis detected monoclonal integration of proviral DNA of HTLV-1 into host genome in the biopsy specimen. The diagnosis of ATLL arising in adrenal glands was established. Despite repeated systemic chemotherapy, the patient died of progressive disease in December 2004. ATLL could primarily involve the adrenal gland and this disease entity should be included in the differential diagnosis of adrenal mass lesions.

Inhibition of constitutively active Jak-Stat pathway suppresses cell growth of human T-cell leukemia virus type 1-infected T-cell lines and primary adult T-cell leukemia cells.

BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1), the etiologic agent for adult T-cell leukemia (ATL), induces cytokine-independent proliferation of T-cells, associated with the acquisition of constitutive activation of Janus kinases (Jak) and signal transducers and activators of transcription (Stat) proteins. Our purposes in this study were to determine whether activation of Jak-Stat pathway is responsible for the proliferation and survival of ATL cells, and to explore mechanisms by which inhibition of Jak-Stat pathway kills ATL cells. RESULTS: Constitutive activation of Stat3 and Stat5 was observed in HTLV-1-infected T-cell lines and primary ATL cells, but not in HTLV-1-negative T-cell lines. Using AG490, a Jak-specific inhibitor, we demonstrated that the activation of Stat3 and Stat5 was mediated by the constitutive phosphorylation of Jak proteins. AG490 inhibited the growth of HTLV-1-infected T-cell lines and primary ATL cells by inducing G1 cell-cycle arrest mediated by altering the expression of cyclin D2, Cdk4, p53, p21, Pim-1 and c-Myc, and by apoptosis mediated by the reduced expression of c-IAP2, XIAP, survivin and Bcl-2. Importantly, AG490 did not inhibit the growth of normal peripheral blood mononuclear cells. CONCLUSION: Our results indicate that activation of Jak-Stat pathway is responsible for the proliferation and survival of ATL cells. Inhibition of this pathway may provide a new approach for the treatment of ATL.

Curcumin targets Akt cell survival signaling pathway in HTLV-I-infected T-cell lines.

The Akt signaling pathway is important for survival and growth of cancer cells. In the present paper we show that the Akt signaling pathway is constitutively activated in human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines and in primary adult T-cell leukemia (ATL) cells. Curcumin, a natural compound present in turmeric, has been studied vigorously as a potent chemopreventive agent for cancer therapy because of its inhibitory effect on proliferation and induction of apoptosis in several tumor cell lines. We investigated the effect of curcumin on Akt activity in HTLV-I-infected T-cell lines and primary ATL cells. Phosphorylated PDK1 is an activator of Akt by phosphorylating Akt. Curcumin reduced phosphorylation of PDK1 and inhibited constitutive activation of Akt. Curcumin activated glycogen synthase kinase (GSK)-3beta, a downstream target of Akt kinase, by inhibiting phosphorylation of this protein. Curcumin reduced the expression of cell cycle regulators, cyclin D1 and c-Myc proteins, which are both degraded by activated GSK-3beta. Our results suggest that activation of the Akt signaling pathway plays an important role in ATL cell survival, and that curcumin may have anti-ATL properties mediated, at least in part, by inhibiting Akt activity. We propose that Akt-targeting agents could be useful for the treatment of ATL. In this regard, curcumin is a potentially promising compound for the treatment of ATL.

NIK-333 inhibits growth of human T-cell leukemia virus type I-infected T-cell lines and adult T-cell leukemia cells in association with blockade of nuclear factor-kappaB signal pathway.

Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type I (HTLV-I) and remains incurable. NIK-333, a novel synthetic retinoid, prevents the recurrence of human hepatoma after surgical resection of primary tumors. We explored the effects of NIK-333 on HTLV-I-infected T-cell lines and ATL cells. NIK-333 inhibited cell proliferation, induced G1 arrest, and resulted in massive apoptosis in all tested HTLV-I-infected T-cell lines and ATL cells, whereas little effect was observed on normal peripheral blood mononuclear cells. NIK-333 treatment decreases the levels of cyclin D1, cyclin D2, cIAP2, and XIAP proteins. Further analysis showed that NIK-333 inactivated nuclear factor-kappaB in HTLV-I-infected T-cell lines. In animal studies, treatment with NIK-333 (100 mg/kg given orally every other day) produced partial inhibition of growth of tumors of a HTLV-I-infected T-cell line transplanted s.c. in severe combined immunodeficient mice. Our results indicate that NIK-333 is a potentially useful therapeutic agent for patients with ATL.

Transactivation of CCL20 gene by Epstein-Barr virus latent membrane protein 1.

CCL20 is expected to play a crucial role in the initiation of immune responses and tumour growth. However, expression of CCL20 in Epstein-Barr virus (EBV)-associated diseases has not been studied. We examined the contribution of EBV infection and EBV-encoded latent membrane protein (LMP)-1 to CCL20 expression. EBV infection and LMP-1 induced CCL20 mRNA expression in the EBV-negative Burkitt lymphoma (BL) cell lines and the embryonic kidney cell line. Histone deacetylase inhibitor-stimulated endogenous LMP-1 also induced CCL20 expression in an EBV-positive BL cell line. Analysis of the CCL20 promoter showed that it was activated by LMP-1 C-terminal activation region (CTAR)-1 and CTAR-2. Co-expression of IkappaB alpha, IkappaB beta, IkappaB kinase (IKK)alpha, IKKbeta, IKKgamma, nuclear factor (NF)-kappaB-inducing kinase and tumour necrosis factor receptor-associated factor 2 dominant-negative constructs with LMP-1 inhibited the activation of the CCL20 promoter by LMP-1, suggesting that LMP-1 induces CCL20 via NF-kappaB signalling. The requirement for the NF-kappaB-binding site in the CCL20 promoter in LMP-1 responsiveness was established. Our results indicate that activation of the NF-kappaB pathway by LMP-1 is required for the activation of CCL20 expression.

Curcumin (diferuloylmethane) inhibits constitutive active NF-kappaB, leading to suppression of cell growth of human T-cell leukemia virus type I-infected T-cell lines and primary adult T-cell leukemia cells.

Adult T-cell leukemia (ATL) is a fatal malignancy of T lymphocytes caused by infection with human T-cell leukemia virus type I (HTLV-I) and remains incurable. Curcumin (diferuloylmethane), the major pigment of the spice turmeric, can be potentially effective by promoting cell apoptosis. Here we examined whether curcumin is effective in the treatment of ATL. Curcumin prevented cell growth of HTLV-I-infected T-cell lines and primary ATL cells but not of normal peripheral blood mononuclear cells. Curcumin induced cell cycle arrest by reducing the expression of cyclin D1, Cdk1 and Cdc25C and apoptosis by reducing the expression of XIAP and survivin. Most of these genes are known to be regulated by NF-kappaB, which plays a critical role in oncogenesis by HTLV-I. Curcumin suppressed constitutive active NF-kappaB of HTLV-I-infected T-cell lines and primary ATL cells by inhibiting phosphorylation of IkappaBalpha. Curcumin also inhibited Tax-induced NF-kappaB transcriptional activity. However, curcumin-induced suppression of cell growth did not correlate with Tax expression level. Curcumin inhibited the growth of HTLV-I-infected T-cell tumors implanted subcutaneously in SCID mice. Our results indicate that curcumin has tumor-suppressive activity against ATL.