Activated Notch1 signaling cooperates with papillomavirus oncogenes in transformation and generates resistance to apoptosis on matrix withdrawal through PKB/Akt.
Invasive cervical tumors, a major subset of human epithelial neoplasms, are characterized by the consistent presence of papillomavirus oncogenes 16 or 18 E6 and E7 products. Cervical tumors also consistently exhibit cytosolic and nuclear forms of Notch1, suggesting the possible persistent activation of the Notch pathway. Here we show that activated Notch1 synergizes with papillomavirus oncogenes in transformation of immortalized epithelial cells and leads to the generation of resistance to anoikis, an apoptotic response induced on matrix withdrawal. This resistance to anoikis by activated Notch1 is mediated through the activation of PKB/Akt, a key effector of activated Ras in transformation. We suggest that activated Notch signaling may serve to substitute for the lack of activated Ras mutations in the majority of human cervical neoplasms.
Rangarajan
A
A
Tata Institute of Fundamental Research, National Centre for Biological Sciences, Bangalore, 560065, India.
Syal
R
R
Selvarajah
S
S
Chakrabarti
O
O
Sarin
A
A
Krishna
S
S
D017209:Apoptosis / Q000502:physiology; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D004268:DNA-Binding Proteins; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D009856:Oncogene Proteins, Viral / Q000502:physiology*; D027383:Papillomaviridae / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D014157:Transcription Factors
D004268:DNA-Binding Proteins; C052603:E6 protein, Human papillomavirus type 18; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; D009856:Oncogene Proteins, Viral; D011518:Proto-Oncogene Proteins; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D014157:Transcription Factors; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt