title: Downregulation of NPM-ALK by siRNA causes anaplastic large cell lymphoma cell growth inhibition and augments the anti cancer effects of chemotherapy in vitro.
abstract: The fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), results from the chromosome translocation t(2;5)(p23;q25) and is present in 50-70 percent of anaplastic large-cell lymphomas (ALCLs). NPM-ALK is a constitutively activated kinase that transforms cells through stimulating several mitogenic signaling pathways. To examine if the NPM-ALK is a potential therapeutic target in ALCL, we used siRNA to specifically downregulate the expression of the NPM-ALK in ALCL cell lines. In this report, we demonstrated viability loss in t(2;5)-positive ALCL cell lines, SUDHL-1 and Karpas 299 cells, but not in lymphoma cell lines without the chromosome translocation, Jurkat and Granta 519 cells. Further study demonstrated that the downregulation of NPM-ALK resulted in decreased cell proliferation and increased cell apoptosis. When used in combination with chemotherapeutic agents, such as doxorubicin, the inhibition of the NPM-ALK augments the chemosensitivity of the tumor cells. These results revealed the importance of continuous expression of NPM-ALK in maintaining the growth of ALCL cells. Our data also suggested that the repression of the fusion gene might be a potential novel therapeutic strategy for NPM-ALK positive ALCLs.
authors.affiliation: Norris Cancer Center, Los Angeles, CA 90033, USA.
authors.forename: Faye Yuan-yi
authors.initials: FY
authors.lastname: Hsu
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.forename: W French
authors.initials: WF
authors.lastname: Anderson
authors.forename: Patrick B
authors.initials: PB
authors.lastname: Johnston
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002889:Chromosomes, Human, Pair 2; D002895:Chromosomes, Human, Pair 5; D015536:Down-Regulation; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D034741:RNA, Small Interfering / Q000627:therapeutic use*; D015398:Signal Transduction; D014178:Translocation, Genetic
chemical_list: D034741:RNA, Small Interfering; C107023:p80(NPM-ALK) protein; D011505:Protein-Tyrosine Kinases