Transient inhibition of NF-kappaB by DHMEQ induces cell death of primary effusion lymphoma without HHV-8 reactivation.
Primary effusion lymphoma (PEL) is a refractory malignancy caused by human herpes virus 8 (HHV-8) in immunocompromised individuals. The tumor cells of PEL are characterized by constitutive NF-kappaB activation. Dehydroxymethylepoxyquinomicin (DHMEQ) is a new NF-kappaB inhibitor and is effective on various tumor cells with constitutively activated NF-kappaB. Thus, in search for a new therapeutic modality of PEL, we examined the effect of DHMEQ on PEL cells. We confirmed constitutive activation of NF-kappaB with subcomponents of p50 and p65 in PEL cell lines. DHMEQ quickly and transiently abrogated NF-kappaB activation and reduced the cell viability in dose- and time-dependent manners, inducing apoptosis through activation of both mitochondrial and membrane pathways. Array analysis revealed that DHMEQ down-regulated expression levels of NF-kappaB target genes, such as interleukin-6 (IL6), Myc, chemokine (C-C motif) receptor 5 (CCR5) and NF-kappaB1, whereas it up-regulated expression levels of some genes involved in apoptosis, and cell cycle arrest. DHMEQ did not reactivate HHV-8 lytic genes, indicating that NF-kappaB inhibition by DHMEQ did not induce virus replication. DHEMQ rescued CB-17 SCID mice xenografted with PEL cells, reducing the gross appearance of effusion. Thus, DHMEQ transiently abrogated the NF-kappaB activation, irreversibly triggering the apoptosis cascade without HHV-8 reactivation. In addition, DHMEQ could rescue the PEL-xenograft mice. Therefore, we suggest DHMEQ as a promising candidate for molecular target therapy of the PEL.
Dabaghmanesh
Nazanin
N
Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Matsubara
Aiko
A
Miyake
Ariko
A
Nakano
Kazumi
K
Ishida
Takaomi
T
Katano
Harutaka
H
Horie
Ryoichi
R
Umezawa
Kazuo
K
Watanabe
Toshiki
T
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003512:Cyclohexanones / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006367:HeLa Cells; D019288:Herpesvirus 8, Human / Q000378:metabolism*; D006801:Humans; D020287:In Situ Nick-End Labeling; D019169:Jurkat Cells; D020014:K562 Cells; D054685:Lymphoma, Primary Effusion / Q000188:drug therapy* / Q000517:prevention & control* / Q000821:virology; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D013997:Time Factors
D000970:Antineoplastic Agents; D001549:Benzamides; D003512:Cyclohexanones; D016328:NF-kappa B; C464444:dehydroxymethylepoxyquinomicin; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9