Small cell lung cancer (SCLC) is a special kind of lung cancer, which comprises 15%-20% of all lung cancers. Different from other lung cancers, SCLC exhibits aggressive behavior with rapid growth and spread to distant sites early[
1]. Although SCLC is exquisite sensitivity to chemotherapy and radiation, it is more prone to relapse and recurrence. Special AT-rich sequence binding protein 1 (SATB1) is a nuclear matrix attachment region binding protein (MBP) which participates in higher-order chromatin organization and tissue-specific gene expression[
2,
3]. SATB1 play an important role in differentiation, and expresses at high level in thymocyte, its expression is down-regulated in mature T cells[
4,
5]. SATB1 has been reported to promote a metastatic phenotype and correlate with poor prognosis in breast cancer[
6]. Its expression has also been associated with unfavourable clinicopathological characteristics and poor prognosis in gastric, liver and colorectal cancer and glioma[
7‐
12]. RNA-interference-mediated knockdown in aggressive cancer cells have altered the expression of over 1,000 genes, this technique effectively inhibited cell capacity of proliferation, invasion, tumor growth and metastasis[
6]. Zheng et al. also found SATB1 expression in aggressive rather than non-aggressive breast cancer cells[
13]. Similarly, transduction of SATB1into non-metastatic cells led to the invasion of tumors in mice[
14], whereas silencing SATB1 lead cells to their normal phenotype and prevented tumor growth and metastasis. RNA interference (RNAi) targeting SATB1 has been successfully used in sarcoma[
15], leukemia[
16] and pancreatic cells[
17], few report has been published concerning the effect of small interfering RNA (siRNA) on the SATB1 gene in SCLC cells, in our study, we investigated the expression of SATB 1 and its role in the pathogenesis of SCLC by knocking down SATB1 in NCI-H446 cells.