Up-regulation of sonic hedgehog contributes to TGF-β1-induced epithelial to mesenchymal transition in NSCLC cells.
BACKGROUND
Lung cancer, especially non-small cell lung cancer (NSCLC) is the major cause of cancer-related deaths in the United States. The aggressiveness of NSCLC has been shown to be associated with the acquisition of epithelial-to-mesenchymal transition (EMT). The acquisition of EMT phenotype induced by TGF-β1in several cancer cells has been implicated in tumor aggressiveness and resistance to conventional therapeutics; however, the molecular mechanism of EMT and tumor aggressiveness in NSCLC remains unknown.


RESULTS
In this study we found for the first time that the induction of EMT by chronic exposure of A549 NSCLC cells to TGF-β1 (A549-M cells) led to the up-regulation of sonic hedgehog (Shh) both at the mRNA and protein levels causing activation of hedgehog signaling. These results were also reproduced in another NSCLC cell line (H2030). Induction of EMT was found to be consistent with aggressive characteristics such as increased clonogenic growth, cell motility and invasion. The aggressiveness of these cells was attenuated by the treatment of A549-M cells with pharmacological inhibitors of Hh signaling in addition to Shh knock-down by siRNA. The inhibition of Hh signaling by pharmacological inhibitors led to the reversal of EMT phenotype as confirmed by the reduction of mesenchymal markers such as ZEB1 and Fibronectin, and induction of epithelial marker E-cadherin. In addition, knock-down of Shh by siRNA significantly attenuated EMT induction by TGF-β1.


CONCLUSIONS
Our results show for the first time the transcriptional up-regulation of Shh by TGF-β1, which is mechanistically associated with TGF-β1 induced EMT phenotype and aggressive behavior of NSCLC cells. Thus the inhibitors of Shh signaling could be useful for the reversal of EMT phenotype, which would inhibit the metastatic potential of NSCLC cells and also make these tumors more sensitive to conventional therapeutics.
Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan, United States of America.
Ma'in Y
MY
Maitah
Shadan
S
Ali
Aamir
A
Ahmad
Shirish
S
Gadgeel
Fazlul H
FH
Sarkar
D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D053823:Hedgehog Proteins / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics*
D053823:Hedgehog Proteins; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1
Oncogene. 2005 Nov 14;24(50):7443-54
16288291
Cell. 2007 Dec 14;131(6):1109-23
18083101
Oncogene. 2010 Jun 17;29(24):3490-500
20418909
Cell. 2009 Aug 21;138(4):645-659
19682730
Respir Res. 2005 Jun 09;6:56
15946381
Cancer. 1995 Jan 1;75(1 Suppl):191-202
8000996
Cancer Res. 2005 Oct 15;65(20):9455-62
16230409
Oncogene. 2009 Oct 8;28(40):3513-25
19633682
Cell. 2004 Aug 6;118(3):277-9
15294153
Nature. 2009 Apr 9;458(7239):776-9
19169242
Carcinogenesis. 2008 Mar;29(3):480-90
18174246
Cell. 1999 Jan 22;96(2):225-33
9988217
Trends Pharmacol Sci. 2009 Jun;30(6):303-12
19443052
Cancer Res. 2006 Jan 15;66(2):944-50
16424029
Nat Clin Pract Oncol. 2008 May;5(5):280-90
18349857
Cancer Res. 2007 Mar 1;67(5):2187-96
17332349
Endocr Relat Cancer. 2007 Sep;14(3):865-74
17914115
Drug Resist Updat. 2008 Aug-Oct;11(4-5):123-51
18718806
Int J Mol Med. 2008 Sep;22(3):271-5
18698484
Nature. 2003 Mar 20;422(6929):313-7
12629553
Trends Mol Med. 2007 Dec;13(12):535-41
17981506
Gastroenterology. 2009 Oct;137(4):1478-1488.e8
19577569
Curr Opin Cell Biol. 2003 Dec;15(6):740-6
14644200
Cell Res. 2009 Jan;19(1):89-102
19050696
Nature. 2003 Oct 23;425(6960):851-6
14520413
Cancer Res. 2009 Sep 15;69(18):7135-9
19738043
Br J Cancer. 2010 Jan 19;102(2):383-91
20010943
Nat Rev Drug Discov. 2006 Dec;5(12):1026-33
17139287
Gene Expr Patterns. 2009 Feb;9(2):94-108
18996226
PLoS One. 2008 Aug 06;3(8):e2888
18682804
Oncogene. 2010 Aug 26;29(34):4741-51
20531305
Clin Cancer Res. 2005 Dec 15;11(24 Pt 1):8686-98
16361555
Biochim Biophys Acta. 2010 Apr;1805(2):181-208
20085802
J Cell Biochem. 2007 Nov 1;102(4):829-39
17914743
Development. 2000 Aug;127(15):3283-93
10887084
Cancer Res. 2007 Jul 15;67(14):6981-6
17638910
Oncogene. 2007 Feb 15;26(7):1046-55
16909105
Stem Cells. 2009 Aug;27(8):1712-21
19544444
J Clin Invest. 2002 Aug;110(3):341-50
12163453
FEBS Lett. 2005 Dec 5;579(29):6681-7
16307741
Bull Mem Acad R Med Belg. 2007;162(3-4):219-23
18075052
Gastroenterology. 2006 Jul;131(1):14-29
16831586
Cancer Res. 2009 Apr 1;69(7):2783-91
19293183
J Clin Invest. 1999 Oct;104(7):855-64
10510326
Nat Rev Cancer. 2009 Apr;9(4):265-73
19262571
J Korean Med Sci. 2007 Oct;22(5):898-904
17982242
Br J Cancer. 2009 Jan 27;100(2):389-98
19107131
Clin Chest Med. 1993 Mar;14(1):1-15
8462243