Cyclin T1 overexpression induces malignant transformation and tumor growth.

Human PTE Fb is a protein kinase composed by CDK9 and Cyclin T that controls the elongation phase of RNA Pol II. This complex also affects the activation and differentiation program of lymphoid cells. In this study we found that several head and neck tumor cell lines overexpress PTE Fb. We also established that Cyclin T1 is able to induce transformation in vitro, as we determined by foci and colony formation assays. Nu/nu mice s.c. injected with stable transfected Cyclin T1 cells (NIH 3T3 Cyclin T1) developed tumors faster than animals injected with control cells (NIH 3T3 beta-gal). In vitro, NIH 3T3 Cyclin T1 cells show increased proliferation and CDK4-Rb phosphorylation. Even more, silencing E2F1 expression (shRNA E2F1) in NIH 3T3 cells resulted in a dramatic inhibition of Cyclin T1-induced foci. All these data demonstrate for the first time the Cyclin T1 oncogenic function and suggest a role for this protein in controlling cell cycle probably via Rb/E2F1 pathway.
AuthorsCristian Moiola, Paola De Luca, Kevin Gardner, Elba Vazquez, Adriana De Siervi
JournalCell cycle (Georgetown, Tex.) (Cell Cycle) Vol. 9 Issue 15 Pg. 3119-26 (Aug 01 2010) ISSN: 1551-4005 [Electronic] United States
PMID20714219 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
Chemical References
  • Cyclin T
  • Retinoblastoma Protein
  • Positive Transcriptional Elongation Factor B
  • CDK4 protein, human
  • CDK9 protein, human
  • Cyclin-Dependent Kinase 4
  • Cyclin-Dependent Kinase 9
  • Animals
  • Cell Line, Tumor
  • Cell Proliferation
  • Cell Transformation, Neoplastic (genetics, pathology)
  • Clone Cells
  • Cyclin T (genetics, metabolism)
  • Cyclin-Dependent Kinase 4 (metabolism)
  • Cyclin-Dependent Kinase 9 (metabolism)
  • Gene Expression Regulation, Neoplastic
  • Head and Neck Neoplasms (enzymology, genetics, pathology)
  • Humans
  • Mice
  • NIH 3T3 Cells
  • Neoplasms (metabolism, pathology)
  • Phosphorylation
  • Positive Transcriptional Elongation Factor B (metabolism)
  • Retinoblastoma Protein (metabolism)
  • Tumor Stem Cell Assay
  • Xenograft Model Antitumor Assays

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