Genentech, Inc.

Curis, Inc.

Assistance Publique-Hopitaux De Paris

Université Paris Diderot-Paris 7

Gerrit J P Dijkgraaf

Frederic J De Sauvage

Robert L Yauch

Thomas E Januario

Hayley Sharpe

Nicole Basset-Seguin

Thomas Januario

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, mutations in the serpentine receptor, Smoothened (SMO) are described, which result in resistance to a Hedgehog (Hh) pathway inhibitor, such as in medulloblastoma. Amino acid substitutions in conserved residues of SMO maintain Hh signaling, but result in the inability of the Hh pathway inhibitor, GDC-0449, to bind SMO and suppress the pathway. In some embodiments, the disclosure provides for novel mutant SMO proteins and nucleic acids and for screening methods to detect SMO mutations and methods to screen for drugs that specifically modulate mutant SMO exhibiting drug resistance.

Mutant smoothened and methods of using the same

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 aspartic 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. This mutation was not only acquired in a GDC-0449-resistant mouse model of medulloblastoma, but was identified in a Medulloblastoma patient following relapse on GDC-0449. The invention provides screening methods to detect SMO mutations and methods to screen for drugs that specifically modulate mutant SMO exhibiting drug resistance.

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.

E518A/K mutant smoothened and methods of using the same

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Gerrit J P Dijkgraaf