Marcelo L. Rodríguez-Puebla, M.Sc., Ph.D.
Assistant Professor of Carcinogenesis

M. Sc.: University of Buenos Aires, School of Natural Sciences
Ph.D.: University of Buenos Aires, Institute of Biochemistry Research "Luis F. Leloir" Cell Biology, 1995
Postdoctoral Fellow: 1996-1999
M. D. Anderson Cancer Center, Smithville, Texas
Assistant Professor of Carcinogenesis: 2000-2002
M. D. Anderson Cancer Center, Smithville, Texas


Phone: (919) 515-7409
Fax: (919) 515-3044
E-mail: Marcelo_Rodriguez-Puebla@ncsu.edu

Research Area:

Cell cycle regulation, skin carcinogenesis, mouse model, tumor biology

Current Research:

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The overall goal of my research is to study the cell-cycle regulation in mouse skin by using transgenic and knockout mouse technology. In mammalian cells, proliferation is under the control of factors that regulate the transitions between different cell-cycle stages at two main checkpoints, the G1/S and the G2/M transition. The D-type cyclins (cyclins D1, D2 and D3) are a family of key cell-cycle regulators that function by association with and activation of cyclin-dependent kinases 4 and 6 (CDKs) at G1 phase to phosphorylate Rb protein that controls the cell cycle progression. Our results show that in an in vivo model of mouse epidermis proliferation D-type cyclins form complexes with CDK4,6 at different time points and in some cases the complex formation is independent of the level of expression of D-type cyclins and CDKs.

In order to study the role of the different cell cycle regulators in vivo, we have developed several transgenic mice that expressed cyclin D2, cyclin D3 or CDK4 in the basal cell layer of squamous epithelia. Also, the development of transgenic mice that overexpressed CDK2 and CDK6 are in progress. Although, all of these transgenic mice developed a hyperproliferative phenotype; the most severe phenotype was observed in K5-CDK4 transgenic animals. They also developed a severe dermal fibrosis and mild epidermal hyperplasia. These animals are also hypersensitive to treatment with the tumor promoter TPA. These results in the K5-CDK4 mice were unexpected because; previous reports showed that expression of the catalytic subunit (CDKs) without concomitant expression of the regulatory subunits (cyclins) does not result in increased proliferation.

We have also studied cell cycle regulation in chemically induced mouse skin tumors. Our preliminary results showed that CDK4 overexpression in epidermal basal cell layer increase malignant conversion of papillomas to squamous cell carcinomas (SCC). CDK4-deficient mice corroborated the importance of CDK4 in tumor development. We found that lack of CDK4 completely inhibit mouse skin tumor development. This study will shed light on the link between cyclin-dependent kinase activities and carcinogenesis.

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Role of c-myc in chemical carcinogenesis

Myc overexpression can immortalize cells, promote cell-cycle progression as well as inhibit differentiation in vitro. K5-Myc transgenic mice showed increased keratinocyte proliferation and spontaneous tumors in epithelial tissues. We have shown that Myc overexpression induces aberrant expression of CDK4 in vivo and moderate expression of cyclin D1, cyclin D2, and cyclin E. Lack of CDK4 in K5-Myc overexpressing mice (K5-Myc/CDK4 null mice) resulted in abrogation of spontaneous tumor development, suggesting that CDK4 is mediating the tumor formation induced by Myc. Biochemical analysis of K5-Myc/CDK4 null epidermis showed that CDK4 mediates the proliferative activities of Myc by sequestering p21 and p27 and indirectly activating CDK2 kinase activity. These results show for the first time that CDK4 mediates Myc's proliferative and oncogenic activities in vivo.

Different CDK4 complexes in mouse epidermis

We are studying the complex formation between CDK4 and protein others than D-type cyclins and cyclin-dependent kinase inhibitors. We have isolated complexes of high molecular weight (more than 600 KDa) which are increased when CDK4 is overexpressed. These complexes are specific for CDK4, and CDK6 protein do not appear to form high molecular complexes. Clearly these complexes are different form the dimmers (CDK and cyclins) and trimmers (CDK, cyclins and CKI). The isolation, composition and roles of novel components of these complexes in normal and neoplastic proliferation are being studied by using molecular size-exclusion chromatography, 2-D gels and proteomic technology.

Role of cyclin D3 in normal and neoplastic proliferation

We have described a negative loop that regulates the protein level of D-type cyclins. This negative loop participates in the regulation of cyclin D3 and cyclin D2. At this moment we are studying the role of this circuit in the deregulation of cyclin D2 in chemical induced mouse tumors. In order to understand how this circuit works in normal and neoplastic proliferation we are using siRNA technology to down-regulate these cell cycle regulators in vivo.

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Representative Publications:

Robles, A.I., Rodriguez-Puebla, M.L., Glick, A.B., Trempus, C., Hansen, L., Sicinski, P., Tennant, R.W., Weinberg, R.A., Yuspa, S.H., and Conti, C.J. Reduced skin tumor development in Cyclin D1 deficient mice highlights the oncogenic ras pathway in vivo. Genes & Dev. 12: 2469-2474, 1998.

Rodriguez-Puebla, M.L., Robles, A.I., and Conti C.J. Ras activity and Cyclin D1 expression: An essential mechanism in mice skins tumor development. Molecular Carcinogenesis 24:1-6, 1999.

Rodriguez-Puebla, M.L., LaCava, M., and Conti, C.J. Cyclin D1 overexpression in mouse epidermis increases Cyclin-dependent Kinase activity and cell proliferation in vivo but does not affect skin tumor development. Cell Growth Differ. 10: 467-472, 1999.

Rodriguez-Puebla, M.L., LaCava, M., Miliani de Marval, P., Jorcano, Jose L., Richie, Ellen R. and Conti C.J. Cyclin D2 overexpression in transgenic mice induces thymic and epidermal hyperplasia whereas cyclin D3 expression results only in epidermal hyperplasia. Am. J. Pathol. 157: 1039-1050, 2000.

Miliani de Marval, P.L., Gimenez-Conti, I.B., LaCava, M., Martinez, L., Conti, C.J. and Rodriguez-Puebla, M.L. Transgenic Expression of cdk4 results in epidermal hyperplasia, hypertrophy and severe dermal fibrosis. Am. J. Pathol. 159:369-379, 2001.

Rodriguez-Puebla, M.L., Miliani de Marval, P.L., LaCava, M., Moons, D.S., Kiyokawa, H., and Conti, C.J. cdk4 Deficiency Inhibits Skin Tumor Development but Does not Affect Normal Keratinocyte Proliferation. Am. J. Pathol. 161: 405-411, 2002.

Rodriguez-Puebla, M.L., Senderowicz, A.M. and Conti, C.J. . "Deregulation of cell cycle progression by oncogenic transformation" in Oncogene-Targeted Therapies, Humana Press, Totowa, NJ., pp. 133-152, 2003.

Miliani de Marval, P.L., Macias, E., Conti, C.J., and Rodriguez-Puebla, M.L. Enhanced Malignant Progression in Cyclin-Dependent Kinase 4 transgenic mice. In Press, 2003.

Macias E., Kim Y, Miliani de Marval P., Klein-Szanto, A., and Rodriguez-Puebla, M.L.Cdk2 deficiency decrease ras/cdk4-dependent malignant progression, but not myc-induced tumorigenesis.Cancer Research 67 (20): 9713-20, 2007.

Macias E., Miliani de Marval P., Senderowicz A., Dlugosz A., Cullen, J and Rodriguez-Puebla, M.L.CDK4 expression is specifically retained in the adult adenohypophysis and collaborates in pituitary tumorigenesis.Cancer Research 68 (1): 162-171, 2008.

Links:

Rodriguez-Puebla Lab Personnel

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