Metabolic abnormalities in adult T-cell leukemia/lymphoma and induction of specific leukemic cell death using photodynamic therapy

Takashi Oka,Yoshihisa Yamano,Tadashi Yoshino,Hirofumi Fujita,Atae Utsunomiya,Tsutomu Masujima,Kozo Utsumi,Masumi Sakata,Hajime Mizuno

doi:10.1038/s41598-018-33175-7

Abstract

Adult T-cell leukemia/lymphoma (ATL) is an aggressive T-cell neoplasm caused by human T-cell leukemia virus type I (HTLV-I). Therapeutic interventions have not been associated with satisfactory outcomes. We showed that the porphyrin metabolic pathway preferentially accumulates the endogenous photosensitive metabolite, protoporphyrin IX (PpIX) in ATL, after a short-term culture with 5-aminolevulinic acid (ALA). PpIX accumulated 10–100-fold more in ATL leukemic cells when compared to healthy peripheral blood mononuclear cells (PBMCs). Patient specimens showed dynamic changes in flow cytometry profiles during the onset and progression of ATL. Furthermore, 98.7% of ATL leukemic cell death in the ATL patient specimens could be induced with 10 min of visible light exposure, while 77.5% of normal PBMCs survived. Metabolomics analyses revealed that a specific stage of the metabolic pathway progressively deteriorated with HTLV-I infection and at the onset of ATL. Therefore, this method will be useful in diagnosing and identifying high-risk HTLV-I carriers with single cell resolutions. Photodynamic therapy in the circulatory system may be a potential treatment due to its highly-specific, non-invasive, safe, simultaneous, and repeatedly-treatable modalities.

Highlights

Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignant disease of the CD4(+) T lymphocytes associated with the human T-lymphotropic virus type I (HTLV-1) infection[1,2,3,4]
The ATL cell line, TLOm1, showed strong Protoporphyrin IX (PpIX) fluorescence when cells were incubated for 24 h in the presence of 1 mM aminolevulinic acid (ALA), whereas no fluorescence was observed in the mock standard culture without ALA (Fig. 1B)
Dose response analyses of ALA against PpIX fluorescence using flow cytometry (FCM) showed PpIX fluorescence saturation in 1.0 mM ALA, which was found to be the optimum concentration for intracellular PpIX accumulation (Fig. 1C,D)

Summary

Introduction

Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignant disease of the CD4(+) T lymphocytes associated with the human T-lymphotropic virus type I (HTLV-1) infection[1,2,3,4]. PpIX absorbs energy directly from a harmless visible light source and transfers the energy to molecular oxygen to create an activated form of oxygen called singlet oxygen (1O2) and other reactive oxygen species (ROS) This singlet oxygen is supposed to be the real cytotoxic agent that reacts rapidly with cellular components and causes the tumor cell damage that leads to cell death with necrosis and/or apoptosis and tumor destruction. The dynamic FCM profile changes observed during the progression of indolent ATL clearly identified patients with high-risk indolent ATL who appeared to have developed or were likely to develop the aggressive subtypes

Methods

Results

Conclusion