A novel exon 15-deleted, splicing variant of Slit2 shows potential for growth inhibition in addition to invasion inhibition in lung cancer

Cancer. 2011 Aug 1;117(15):3404-15. doi: 10.1002/cncr.25890. Epub 2011 Jan 24.

Abstract

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-ΔE15) 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-ΔE15 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-ΔE15 greatly suppresses cell growth.

Conclusions: The data demonstrated that exon 15 modulates Slit2 function in growth inhibition of lung cancer cells. Because slit2-ΔE15 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / genetics
  • Adenocarcinoma / pathology*
  • Animals
  • Base Sequence
  • Blotting, Western
  • Cell Division / genetics*
  • Cell Line, Tumor
  • Culture Media, Conditioned
  • DNA Primers
  • Exons*
  • Flow Cytometry
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / pathology*
  • Mice
  • Mice, SCID
  • Nerve Tissue Proteins / genetics*
  • Polymerase Chain Reaction
  • RNA Splicing*
  • RNA, Small Interfering

Substances

  • Culture Media, Conditioned
  • DNA Primers
  • Intercellular Signaling Peptides and Proteins
  • Nerve Tissue Proteins
  • RNA, Small Interfering
  • Slit homolog 2 protein