Restoration of SOCS3 suppresses human lung adenocarcinoma cell growth by downregulating activation of Erk1/2, Akt apart from STAT3.
SOCS3 is regarded as a major negative regulator of STAT3. Recent evidence indicates that SOCS3 regulates strength and duration of other signaling pathways including ras/ERK1/2/MAPK, PI3-K/Akt in non-malignant cells. The repression or silence of SOCS3 expression in a few tumor types has led to speculation that loss of SOCS3 gene is closely related to deregulation of multiple signal pathways during tumorigenesis. However, apart from STAT3, little is known in malignant cells about the mechanism by which SOCS3 modulates other intracellular signal cascades such as Erk1/2 and Akt, whose aberrant activation has been implicated in many human tumors. Expression of SOCS3 proved deficient in human lung adenocarcinoma A549 cells, and forced expression of SOCS3 resulted in growth inhibition. Growth suppression due to SOCS3 was associated with attenuated activation of Erk1/2, Akt as well as STAT3. The results suggested that SOCS3, as negative regulators of cytokine signaling, might maintain homeostasis by regulating multiple signaling pathways and reverse cell malignant behavior.
Yu
Zu-Bin
ZB
Department of Thoracic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, PR China.
Bai
Li
L
Qian
Pin
P
Xiao
Yin-Bin
YB
Wang
Guan-Song
GS
Qian
Gui-Sheng
GS
Bai
Chun-Xue
CX
Min
Jia-Xin
JX
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
C106644:SOCS3 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3