Myosin light chain kinase is responsible for high proliferative ability of breast cancer cells via anti-apoptosis involving p38 pathway.
OBJECTIVE
To investigate whether myosin light chain kinase (MLCK) contributed to the high proliferative ability of breast cancer cells.


METHODS
Soft agar colony formation on the MCF-7 and LM-MCF-7 cell lines was determined. The cell cycles of MCF-7 and LM-MCF-7 were detected using flow cytometry analysis. Western blot analysis was performed to detect the expression levels of p-ERK1/2, total-ERK1/2, p-p38, total p38, p-JNK, total-JNK, survivin, Bcl-2, p-MLC, caspase-9, cleaved caspase-9, and MLCK. After treatment with adriamycin (ADR), ML-7 and SB203580, apoptosis was examined using flow cytometry analysis and Annexin V-FITC fluorescence microscopy.


RESULTS
The breast cancer LM-MCF-7 cell line with high metastasis potential (a metastitic sub-clone of MCF-7) had higher anti-apoptosis ability relative to MCF-7 cells in response to adriamycin treatment (apoptosis rate: 6.76% vs 28.58%, P<0.05). Moreover, the expression level of MLCK was upregulated and the level of phosphorylated p38 (p-p38) was decreased in LM-MCF-7 cells. Flow cytometry analysis showed that ML-7, selective inhibitor of MLCK, could induce apoptosis of the LM-MCF-7 cells, in which the level of p-p38 was increased. Meanwhile, the expression levels of Bcl-2 and survivin were downregulated, while the caspase-9 was upregulated suggesting that the cells were undergone apoptosis. Flow cytometry analysis showed that SB203580, an inhibitor of p38, abolished ML-7-induced apoptosis, which resulted in the upregulation of Bcl-2 and survivin, and downregulation of caspase-9, suggesting that Bcl-2, survivin and caspase-9 are downstream effectors of p38.


CONCLUSIONS
MLCK is responsible for high proliferative ability of breast cancer cells through anti-apoptosis, in which p38 pathway was involved.
Cui
Wen-jing
WJ
Department of Biochemistry, the Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
Liu
Yi
Y
Zhou
Xiao-lei
XL
Wang
Feng-ze
FZ
Zhang
Xiao-dong
XD
Ye
Li-hong
LH
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004317:Doxorubicin / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D020935:MAP Kinase Signaling System; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D009362:Neoplasm Metastasis; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin; D009219:Myosin-Light-Chain Kinase; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases
Cancer. 2003 Jun 15;97(12):3017-26
12784337
Acta Pharmacol Sin. 2007 Mar;28(3):431-8
17303008
Zhonghua Yi Xue Za Zhi. 2006 Jan 3;86(1):61-5
16606541
Oncogene. 2004 Apr 12;23(16):2838-49
15077147
Mol Cell Biol. 2005 Jul;25(14):6259-66
15988034
Nat Rev Cancer. 2003 Dec;3(12):931-43
14737123
Nat Rev Cancer. 2003 Nov;3(11):859-68
14668816
J Cell Biochem. 2005 Feb 1;94(2):351-64
15526279
FASEB J. 2003 Mar;17(3):407-16
12631580
Acta Pharmacol Sin. 2010 Feb;31(2):202-10
20139903
Acta Biochim Biophys Sin (Shanghai). 2008 Apr;40(4):304-10
18401528
Am J Physiol Lung Cell Mol Physiol. 2001 Jun;280(6):L1168-78
11350795
Breast Cancer Res. 2006;8(6):216
17164010
Immunol Rev. 2009 Mar;228(1):212-24
19290930
Curr Med Chem. 2009;16(10):1229-35
19355881
Biochem Biophys Res Commun. 2003 Jun 20;306(1):244-9
12788095
Cancer Cell. 2003 Jan;3(1):51-62
12559175
Eur J Cancer. 2006 May;42(7):948-57
16574402
Oncogene. 2003 Sep 1;22(37):5885-96
12947395
Nat Rev Cancer. 2006 Jun;6(6):449-58
16723991
Gut. 2003 Jan;52(1):144-51
12477778
Semin Arthritis Rheum. 2003 Jun;32(6):345-69
12833244
Exp Eye Res. 2005 Jun;80(6):777-85
15939033
Hepatogastroenterology. 2008 May-Jun;55(84):930-5
18705300
J Cell Sci. 2006 Jun 1;119(Pt 11):2269-81
16723733
Cancer Lett. 2008 Nov 8;270(2):312-27
18710790
Endocrinology. 2009 Apr;150(4):1607-17
19008312
Breast Cancer Res. 2001;3(3):150-3
11305949
Acta Pharmacol Sin. 2008 Mar;29(3):333-40
18298898
Pol Merkur Lekarski. 2007 Dec;23(138):403-7
18432121
Science. 2003 Mar 21;299(5614):1859-63
12649474