Mutant p53 disrupts role of ShcA protein in balancing Smad protein-dependent and -independent signaling activity of transforming growth factor-β (TGF-β).
Biomarkers are lacking for identifying the switch of transforming growth factor-β (TGF-β) from tumor-suppressing to tumor-promoting. Mutated p53 (mp53) has been suggested to switch TGF-β to a tumor promoter. However, we found that mp53 does not always promote the oncogenic role of TGF-β. Here, we show that endogenous mp53 knockdown enhanced cell migration and phosphorylation of ERK in DU145 prostate cancer cells. Furthermore, ectopic expression of mp53 in p53-null PC-3 prostate cancer cells enhanced Smad-dependent signaling but inhibited TGF-β-induced cell migration by down-regulating activated ERK. Reactivation of ERK by the expression of its activator, MEK-1, restored TGF-β-induced cell migration. Because TGF-β is known to activate the MAPK/ERK pathway through direct phosphorylation of the adaptor protein ShcA and MAPK/ERK signaling is pivotal to tumor progression, we investigated whether ShcA contributed to mp53-induced ERK inhibition and the conversion of the role of TGF-β during carcinogenesis. We found that mp53 expression led to a decrease of phosphorylated p52ShcA/ERK levels and an increase of phosphorylated Smad levels in a panel of mp53-expressing cancer cell lines and in mammary glands and tumors from mp53 knock-in mice. By manipulating ShcA levels to regulate ERK and Smad signaling in human untransformed and cancer cell lines, we showed that the role of TGF-β in regulating anchorage-dependent and -independent growth and migration can be shifted between growth suppression and migration promotion. Thus, our results for the first time suggest that mp53 disrupts the role of ShcA in balancing the Smad-dependent and -independent signaling activity of TGF-β and that ShcA/ERK signaling is a major pathway regulating the tumor-promoting activity of TGF-β.
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229.
Shu
S
Lin
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229.
Lan
L
Yu
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229.
Junhua
J
Yang
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229.
Zhao
Z
Liu
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229; Greehey Children's Cancer Research Institute, University of Texas Health Science Center, San Antonio, Texas 78229.
Bijal
B
Karia
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229; Greehey Children's Cancer Research Institute, University of Texas Health Science Center, San Antonio, Texas 78229; Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas 78229.
Alexander J R
AJR
Bishop
Department of Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.
James
J
Jackson
Department of Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.
Guillermina
G
Lozano
Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida 32224.
John A
JA
Copland
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229; Key Laboratory of Living Donor Liver Transplantation, First Affiliated Hospital of Nanjing Medical University, Nanjing, China 210009.
Xiaoxin
X
Mu
Key Laboratory of Living Donor Liver Transplantation, First Affiliated Hospital of Nanjing Medical University, Nanjing, China 210009.
Beicheng
B
Sun
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229; Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas 78229. Electronic address: sunl@uthscsa.edu.
Lu-Zhe
LZ
Sun
D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D016158:Genes, p53; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D011471:Prostatic Neoplasms / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism*; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism
D014408:Biomarkers, Tumor; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D051785:Smad Proteins; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016212:Transforming Growth Factor beta; D016159:Tumor Suppressor Protein p53; D048049:Extracellular Signal-Regulated MAP Kinases