Transcription factors Sp1 and p73 control the expression of the proapoptotic protein NOXA in the response of testicular embryonal carcinoma cells to cisplatin.
Testicular germ cell tumors (TGCTs) are highly responsive to and curable by cisplatin-based chemotherapy even in advanced stages. We have studied the molecular mechanisms involved in the induction of apoptosis in response to cisplatin, and found that proapoptotic Noxa is transcriptionally up-regulated following cisplatin exposure, even in the absence of p53, in NTERA2 cisplatin-sensitive cells but not in 1411HP-resistant cells. Blockade of Noxa reduced the apoptotic response of embryonal carcinoma (EC) NTERA2 cells to cisplatin. A detailed analysis of the Noxa promoter revealed that p73 and Sp1-like factors, Sp1 and KLF6, played key roles in the transcriptional control of this gene. Overexpression of TAp73 induced Noxa whereas the dominant negative isoform ΔNp73, reduced the levels of Noxa after cisplatin exposure in NTERA2 and 2102EP. Interestingly, down-regulation of Sp1 increased Noxa expression in response to cisplatin. However, blockade of KLF6 decreased cisplatin-induced up-regulation of Noxa in EC cell lines. In addition, tissue microarray analyses of TGCTs revealed that expression of Noxa correlates with good clinical prognosis in patients with embryonal carcinoma. Thus, our data show the transcriptional network that regulates Noxa in EC cells, which is key for their apoptotic response to cisplatin-based chemotherapy, and propose Noxa as a predictive factor of therapeutic response.
Molecular Genetics Unit, Hospital Valdecilla, and Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Av. Cardenal Herrera Oria s/n, 39011 Santander, Spain.
Lara
L
Grande
Gabriel
G
Bretones
Manuel
M
Rosa-Garrido
Eva M
EM
Garrido-Martin
Teresa
T
Hernandez
Susana
S
Fraile
Luisa
L
Botella
Enrique
E
de Alava
August
A
Vidal
Xavier
X
Garcia del Muro
Alberto
A
Villanueva
M Dolores
MD
Delgado
Jose L
JL
Fernandez-Luna
D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000502:physiology*; D001483:Base Sequence; D018236:Carcinoma, Embryonal / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology* / Q000627:therapeutic use; D015331:Cohort Studies; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000502:physiology*; D011379:Prognosis; D011401:Promoter Regions, Genetic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D016329:Sp1 Transcription Factor / Q000502:physiology*; D013736:Testicular Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000502:physiology*
D000970:Antineoplastic Agents; D017931:DNA Primers; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D016329:Sp1 Transcription Factor; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human; D002945:Cisplatin