The goal of our laboratory is to investigate mechanisms of tumorigenesis and
tumor progression, and to apply genome-wide techniques to develop anti-cancer
therapies. Our research focuses on transcriptional regulation of gene expression
during stem cell self-renewal and differentiation and during tumorigenesis. Tumor
cells acquire malignant behavior by altering many signaling pathways. Dysregulation
of gene transcription plays a pivotal role in generating phenotypic plasticity. For
example, epithelial tumors are able to re-activate embryonary genetic programs, which
allow tumor cells to migrate and disseminate. The diversity of transcriptional
aberrations in cancer poses a basic obstacle to successful therapies, which would
require simultaneous targeting of many pathways. The strategy that my laboratory has
adopted takes advantage of tumor cell regulatory networks. First, we use artificial
transcription factors (ATFs) as genetic probes to identify genes and gene pathways
responsible for the appearance of specific malignant phenotypes. Second, we investigate
the ability of ATFs to interfere with tumor cell regulatory programs. Cancer cell
reprogramming with such artificial “genetic switches” may afford a new
therapeutic strategy. In its simplest design, an ATF is composed of a DNA binding domain
(DBD) and an effector domain (activator or repressor). A variety of molecular scaffolds
have been used as DBDs, from chemical molecules to natural protein domains. One of the
ATF scaffolds that we use is based on the Cys2-His2 zinc finger (ZF) domain. We have
constructed multi-finger proteins specifically recognizing consecutive triplets of DNA
by linkage of several sequence-specific ZF domains. When directed to specific DNA sequences
in targeted promoters, ATFs can regulate endogenous genes involved in tumor progression.
We also use large libraries of ATFs made by recombination of highly specific ZF domains to
regulate cancer cell behavior. Additionally, the functional screens of ATFs in cancer cells
aim to identify novel targets of neoplastic disease progression. We expect that ATF screens
will provide functional insights and experimental validation of markers associated with poor
clinical outcome. (Figure of Zinc Finger.)
Recent Publications:
Dreier, B., Fuller, R.P., Segal, D.J., Lund, C., Blancafort, P., Huber, A., Koksch, B., and Barbas, C.F.III.
(2005) Development of zinc finger domains for recognition of the 5’-CNN-3’ family DNA sequences and their use
in the construction of artificial transcription factors. J Biol Chem 280(42): 35588-97. Abstract
Blancafort, P., Chen, E, Gonzalez, B, Bergquist, S., Zijlstra, A,, Guthy, D., Brachat, A., Brakenhoff, R., Quigley,
J., Edrmann, D., and Barbas C.F.III. (2005) Genetic reprogramming of tumor cells by zinc finger
transcription factors. Proc Natl Acad Sci 102(33): 11716-21.
Abstract
Magnenat, L., Blancafort, P. and Barbas III, C.F. (2004). In vivo library selection and designed affinity manuration of polydactyl zinc finger transcription factors for ICAM-1 gene regulation. J Mol Biol 341(3): 635-49. Abstract
Blancafort, P., Segal, D.J., and Barbas III, C.F. (2004). Designing transcription factor architectures for drug design. Mol Pharmacol 66(6): 1361-7. Abstract
Lund, C.V, Blancafort, P., Popkov, M. and Barbas III, C.F. (2004) Promoter-targeted Phage Display Selections with Preassembled Synthetic Zinc Finger Libraries for Endogenous Gene Regulation. J Mol Biol 340(3): 599-613. Abstract
