Human T-cell leukemia virus type 1 (HTLV-1) Tax1 oncoprotein but not HTLV-2 Tax2 induces the expression of OX40 ligand by interacting with p52/p100 and RelB.

Human T-cell leukemia virus type 1 (HTLV-1) is a causative retrovirus of adult T-cell leukemia and HTLV-1-associated myelopathy. Unlike HTLV-1, the same group of retrovirus HTLV-2 has not been found to be associated with these diseases. HTLV-1 and HTLV-2 encode transforming proteins Tax1 and Tax2, and a few distinct activities of Tax1 from those of Tax2 have been proposed to contribute to the HTLV-1-specific pathogenesis of disease. One significant difference of Tax1 from Tax2 is the activation of transcription factor NF-κB2/p100/p52. We found that Tax1 but not Tax2 induces the expression of OX40 ligand (OX40L) in a human T-cell line. To induce the OX40L expression, Tax1 but not Tax2 was observed to interact with NF-κB2/p100/p52 and RelB and the distinct interaction activity was mediated by the Tax1 amino acid region of 225-232. In addition, Tax1 but not Tax2 or Tax1/225-232 interacted with p65, p50, and c-Rel; however, the interactions were much less than those noted with NF-κB2/p100/p52 and RelB. OX40L is a T-cell costimulatory molecule of the tumor necrosis factor family, and its signal plays a critical role in establishing adaptive immunity by inducing the polarized differentiation of T-cells to cells such as T helper type 2 and T follicular helper cells. Therefore, the present findings suggest that Tax1 might alter the immune response to HTLV-1 and/or differentiation of HTLV-1-infected T-cells via OX40L induction, thereby acting as a factor mediating the distinct phenotypes and pathogenesis of HTLV-1 from that of HTLV-2.

Effect of double platinum agents, combination of miriplatin-transarterial oily chemoembolization and cisplatin-hepatic arterial infusion chemotherapy, in patients with hepatocellular carcinoma: Report of two cases.

Hepatocellular carcinoma (HCC) is one of the most common cancers and the third highest cause of cancer-associated mortality worldwide. The treatment of HCC is complicated by its variable biological behavior and the frequent coexistence of chronic liver disease, particularly cirrhosis. To date, multiple treatment modalities have been developed according to the stage of the tumor and the hepatic functional reserve, including transarterial treatments such as transarterial chemoembolization, transarterial oily chemoembolization (TOCE), and hepatic arterial infusion chemotherapy (HAIC). We conducted a phase I and II study of the combination therapy with double platinum agents, miriplatin and cisplatin, and confirmed its safety and efficacy. Here, we describe two cases of unresectable HCC who were successfully treated by miriplatin-TOCE/cisplatin-HAIC combination therapy, resulting in complete responses with no significant adverse events. This report will provide that the combination therapy can be the therapeutic option for HCC patients in the advanced stage.