Identification of tyrosine kinase, HCK, and tumor suppressor, BEM, as potential mediators of AHI- oncogene in primary and transformed CTCL cells

摘要

AHI- is an oncogene often targeted by provirus insertional mutagenesis in mu-rine ieukemias and lymphomas. Aberrant expression of human AHI- occurs in cutaneous T-ceil lymphoma (CTCL) cells and in CD+CD7~ Sezary cells from patients with Sezary syndrome. Stable knockdown of AHI- using retroviral-mediated RNA interference in CTCL cells inhibits their transforming activity in vitro and in vivo. To identify genes involved in AHM-mediated transformation, microar-ray analysis was performed to identifydifferentially expressed genes in AHI--suppressed CTCL cells. Fifteen up-regulated and down-regulated genes were identified and confirmed by quantitative reverse transcription-polymerase chain reaction. Seven were further confirmed in a microarray analysis of CD+CD7~ Sezary cells from Sezary syndrome patients. HCK and BIN emerged as new candidate cooperative genes, with differential protein expression, which correlates with observed transcript changes. Interestingly, changes in HCK phosphorylation and biologic re-sponse to its inhibitor, dasatinib, were observed in AWM-suppressed or -over-expressed cells. The tumor suppressor BIN physically interacts with MYC in CTCL cells, which also exhibit differential MYC protein expression. In addition, aberrant expression of alternative splicing forms of BIN was observed in primary and transformed CTCL cells. These findings indicate that HCK and BIN may play critical roles in AH/-J-mediated leukemic transformation of human CTCL cells.