1
|
Bryan C, Rice C, Hoffman H, Harkisheimer M, Sweeney M, Skordalakes E. Structural Basis of Telomerase Inhibition by the Highly Specific BIBR1532. Structure 2015; 23:1934-1942. [PMID: 26365799 DOI: 10.1016/j.str.2015.08.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 01/03/2023]
Abstract
BIBR1532 is a highly specific telomerase inhibitor, although the molecular basis for inhibition is unknown. Here we present the crystal structure of BIBR1532 bound to Tribolium castaneum catalytic subunit of telomerase (tcTERT). BIBR1532 binds to a conserved hydrophobic pocket (FVYL motif) on the outer surface of the thumb domain. The FVYL motif is near TRBD residues that bind the activation domain (CR4/5) of hTER. RNA binding assays show that the human TERT (hTERT) thumb domain binds the P6.1 stem loop of CR4/5 in vitro. hTERT mutations of the FVYL pocket alter wild-type CR4/5 binding and cause telomere attrition in cells. Furthermore, the hTERT FVYL mutations V1025F, N1028H, and V1090M are implicated in dyskeratosis congenita and aplastic anemia, further supporting the biological and clinical relevance of this novel motif. We propose that CR4/5 contacts with the telomerase thumb domain contribute to telomerase ribonucleoprotein assembly and promote enzymatic activity.
Collapse
Affiliation(s)
- Christopher Bryan
- The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA; Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Cory Rice
- The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA; Department of Biochemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hunter Hoffman
- The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA
| | | | - Melanie Sweeney
- The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA; Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Emmanuel Skordalakes
- The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA; Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA; Department of Biochemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
2
|
Abstract
Inappropriate activation of a single enzyme, telomerase, is associated with the uncontrollable proliferation of cells observed in as many as 90% of all of human cancers. Since the mid-1990s, when telomerase activity was detected in human tumors, scientists have eyed the enzyme as an ideal target for developing broadly effective anticancer drugs. One of the missing links in the effort to identify such therapies has been the high-resolution structure of the enzyme, a powerful tool used for the identification and development of clinical drugs. A recent structure of the catalytic subunit of teleomerase from the Skordalakes laboratory, a major advancement in the field of telomeres, has opened the door to the development of new, broadly effective cancer drugs, as well as anti-aging therapies. Here we present a brief description of telomerase biology, current efforts to identify telomerase function modulators and the potential importance of the telomerase structure in future drug development.
Collapse
Affiliation(s)
- Emmanuel Skordalakes
- Gene Expression & Regulation Program, The Wistar Institute, 3601 Spruce St, Philadelphia, PA 19104, USA
| |
Collapse
|
3
|
Folini M, Gandellini P, Zaffaroni N. Targeting the telosome: therapeutic implications. Biochim Biophys Acta Mol Basis Dis 2009; 1792:309-16. [PMID: 19419699 DOI: 10.1016/j.bbadis.2009.01.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 01/28/2009] [Accepted: 01/30/2009] [Indexed: 12/12/2022]
Abstract
Since telomere integrity is required to guarantee the unlimited replicative potential of cancer cells, telomerase, the enzyme responsible for telomere length maintenance in most human tumors, and lately also telomeres themselves have become extremely attractive targets for new anticancer interventions. At the current status of knowledge, it is still not possible to define the best therapeutic target between telomerase and telomeres. It is noteworthy that interfering with telomeres, through direct targeting of telomeric DNA or proteins involved in the telosome complex, could negatively affect the proliferative potential not only of tumors expressing telomerase activity but also of those that maintain their telomeres through alternative lengthening or still unknown mechanisms. This review presents the different therapeutic approaches proposed thus far and developed in preclinical tumor models and discusses the perspectives for their use in the clinical setting.
Collapse
Affiliation(s)
- Marco Folini
- Department of Experimental Oncology and Laboratories, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milan, Italy
| | | | | |
Collapse
|