A Novel Exon 15-Deleted, Splicing Variant of Slit2 Shows Potential for Growth Inhibition in Addition to Invasion Inhibition in Lung Cancer

作者:Lin Yu Ying; Yang Chun Hung; Sheu Gwo Tarng; Huang Chi Ying F; Wu Yu Chung; Chuang Shu Ming; Fann Ming Ji; Chang Han; Lee Huei; Chang Jinghua Tsai*
来源:Cancer, 2011, 117(15): 3404-3415.
DOI:10.1002/cncr.25890

摘要

BACKGROUND: The axon guidance cue molecule Slit2 has been shown to suppress cancer cell invasion. However, the role of Slit2 in growth inhibition is still controversial. The authors identified a novel exon 15 (AKEQYFIP)-deleted slit2, located at the end of the second leucine-rich repeat (LRR2). Because LRR2 interacts with Robo1 receptor to inhibit invasion, they hypothesized that exon 15 plays an important role in modulating Slit2 function. METHODS: Slit2 expression was assessed via microarray analysis in 27 lung adenocarcinomas. Exon 15-deleted slit2 (slit2-Delta E15) and exon 15-containing slit2 (slit2-WT) were cloned and expressed in the CL1-5 lung cancer cell line. The effect of exon 15 on Slit2-mediated cell growth was evaluated by a xenografted model and in vitro cell growth assays. The effect of exon 15 on Slit2-mediated invasion was analyzed with a modified Boyden chamber in vitro. RESULTS: Tumor growth from CL1-5/Slit2-WT cells was comparable to that from CL1-5 cells bearing empty vector. However, tumor size from CL1-5/Slit2-Delta E15 cells was much smaller than that from Slit2-WT cells or vector control cells in the xenografted model. In vitro analyses demonstrated that Slit2-WT inhibits invasion of CL1-5 cells. In addition to inhibiting invasion, Slit2-Delta E15 greatly suppresses cell growth. CONCLUSIONS: The data demonstrated that exon 15 modulates Slit2 function in growth inhibition of lung cancer cells. Because slit2-Delta E15 splice variant is present in low invasive cancer cells and nontumor lung tissues, loss of this splice variant is an important event in tumor progression and invasion. Cancer 2011;117:3404-15.

全文