Mutant smoothened and methods of using the same

• US 8,481,680 B2
• Filed: 10/05/2011
• Issued: 07/09/2013
• Est. Priority Date: 10/05/2010
• Status: Active Grant

• Current Assignee: Curis, Inc.
• Original Assignee: Curis, Inc., Genentech, Inc. (Roche Holding AG)
• Inventors: de Sauvage, Frederic J., Dijkgraaf, Gerrit J. P.
• Primary Examiner(s): STOICA, ELLY GERALD
• Application Number:
  US13/253,317
• Publication Number:
  US 20120039893A1
• Time in Patent Office: 643 Days
• Field of Search: None
• US Class Current: 530/350
• CPC Class Codes: A61P 35/00 Antineoplastic agents
• CPC Class Codes: A61P 43/00 Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• CPC Class Codes: C07K 14/705 Receptors; Cell surface antigens; Cell surface determinants tumour specific antigens C07K14/4748
• CPC Class Codes: C07K 14/723 G protein coupled receptor, e.g. TSHR-thyrotropin-receptor, LH/hCG receptor, FSH receptor

Abstract

The emergence of mutations in tyrosine kinases following treatment of cancer patients with molecular-targeted therapy represents a major mechanism of acquired drug resistance. Here, we describe a mutation in the serpentine receptor, Smoothened (SMO), which results in resistance to a Hedgehog (Hh) pathway inhibitor in medulloblastoma. A single amino acid substitution in a conserved glutamic acid residue of SMO maintains Hh signaling, but results in the inability of the Hh pathway inhibitor, GDC-0449, to bind SMO and suppress the pathway. The invention provides screening methods to detect SMO mutations and methods to screen for drugs that specifically modulate mutant SMO exhibiting drug resistance.

Claims

1. An isolated mutant SMO protein comprising the amino acid sequence of SEQ ID NO:

2, wherein said amino acid sequence comprises alanine (A) or lysine (K) at amino acid 518.

2. A method of screening for compounds that inhibit signaling of a mutant SMO protein according to claim 1, comprising contacting said mutant SMO with a test compound and detecting binding of said compound to said mutant SMO whereby binding of said test compound to mutant SMO indicates that said test compound is an inhibitor of mutant SMO.

3. A method of screening for compounds that inhibit signaling of a mutant SMO protein according to claim 1, comprising contacting a cell that expresses said mutant SMO with a test compound and detecting activity of Gli in said cell whereby the presence of Gli activity indicates that said test compound is not an inhibitor of mutant SMO.