Search

Purpose: Indoleamine 2,3-dioxygenase 1 (IDO1: IDO), an enzyme catabolizing tryptophan (Trp) into the kynurenine (Kyn) pathway, is increasingly being recognized as an important microenvironmental factor suppressing antitumor immune responses. The purpose of the present study was to determine the prognostic significance of Trp catabolism in adult T-cell leukemia/lymphoma (ATL). Experimental Design: We quantified serum Trp and Kyn in 96 ATL patients, 38 human T-cell lymphotropic virus type-1 asymptomatic carriers (HTLV-1 ACs), and 40 healthy adult volunteer controls. The relationships between various clinical parameters including overall survival were analyzed. IDO expression was evaluated in the affected lymph nodes of ATL patients. Results: Serum Kyn concentrations and Kyn/Trp ratios were significantly higher in HTLV-1 ACs than healthy controls. Both increased significantly with progression from HTLV-1 AC to ATL. However, there were no significant differences in the serum Trp concentrations between ATL patients, HTLV-1 ACs, and controls. IDO was possibly produced by ATL and/or cells of the microenvironment. Multivariate analyses demonstrated that a high serum Kyn/Trp ratio and high Kyn level, but not a high Trp level, were significantly independent detrimental prognostic factors in ATL, as well as in that subset of patients with aggressive variant ATL. Conclusions: Quantification of serum Kyn and Trp is useful for predicting prognosis of an individual ATL patient. Furthermore, ATL, especially in patients with a high serum Kyn/Trp ratio, is an appropriate disease for testing novel cancer immunotherapies targeting IDO. Clin Cancer Res; 21(12); 2830–9. ©2015 AACR.

CCND1, FGFR3 and c-MAF mRNA expression of tumor samples from 123 multiple myeloma patients were analyzed by global RQ/RT-PCR. CCND1, FGFR3 and c-MAF were positive in 44 (36%), 28 (23%) and 16 (13%) of patients, respectively. In 7 patients, both FGFR3 and c-MAF were positive. The expression of c-MAF was independent unfavorable prognostic factors for overall survival (OS). Autologous stem cell transplantation improved progression-free survival of CCND1-positive patients. Bortezomib, thalidomide or lenalidomide extended OS of FGFR3 and/or c-MAF-positive patients. Thus, CCND1, FGFR3 and c-MAF mRNA expression can predict survival and is useful for planning stratified treatment strategies for myeloma patients.

NF-kappaB is constitutively activated in adult T-cell leukemia (ATL) and is considered responsible for cell growth and prevention of cell death. In this study, we demonstrate that NF-kappaB is constitutively activated in various HTLV-1-infected T-cell lines and ATL-derived cell lines irrespectively of Tax expression as evidenced by the phosphorylation of IkappaBalpha and p65 subunit of NF-kappaB, activation of NF-kappaB DNA binding, and upregulation of various target genes including bcl-xL, bcl-2, XIAP, c-IAP1, survivin, cyclinD1, ICAM-1 and VCAM-1. The effects of a novel IkappaB kinase (IKK) inhibitor, 2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-piperidin-4-yl nicotinonitrile (ACHP), were examined on cell growth of these cell lines and fresh ATL leukemic cells. We found that ACHP could inhibit the phosphorylation of IkappaBalpha and p65, as well as NF-kappaB DNA-binding, associated with downregulation of the NF-kappaB target genes and induce cell growth arrest and apoptosis in these cells. When Tax-active and Tax-inactive cell lines were compared, ACHP could preferentially inhibit cell growth of Tax-active cells. Moreover, ACHP exhibited strong apoptosis-inducing activity in fresh ATL cells. These findings indicate that ACHP and its derivatives are effective in inducing ATL cell death and thus feasible candidates for the treatment of ATL.

Involvement of nuclear factor-κB (NF-κB) in cell survival and proliferation of multiple myeloma has been well established. In this study we observed that NF-κB is constitutively activated in all human myeloma cell lines, thus confirming the previous studies. In addition, we found the phosphorylation of p65 subunit of NF-κB in addition to the phosphorylation of IκBα and the activation of NF-κB DNA binding and that various target genes of NF-κB including bcl-xL, XIAP, c-IAP1, cyclin D1, and IL-6 are up-regulated. We then examined the effect of a novel IκB kinase inhibitor, 2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-piperidin-4-yl nicotinonitrile (ACHP). When myeloma cells were treated with ACHP, the cell growth was efficiently inhibited with IC50 values ranging from 18 to 35 μmol/L concomitantly with inhibition of the phosphorylation of IκBα/p65 and NF-κB DNA-binding, down-regulation of the NF-κB target genes, and induction of apoptosis. In addition, we observed the treatment of ACHP augmented the cytotoxic effects of vincristine and melphalan (l-phenylalanine mustard), conventional antimyeloma drugs. These findings indicate that IκB kinase inhibitors such as ACHP can sensitize myeloma cells to the cytotoxic effects of chemotherapeutic agents by blocking the antiapoptotic nature of myeloma cells endowed by the constitutive activation of NF-κB.