Hedgehog pathway mutations drive oncogenic transformation in high-risk T-cell acute lymphoblastic leukemia.

The role of Hedgehog signaling in normal and malignant T-cell development is controversial. Recently, Hedgehog pathway mutations have been described in T-ALL, but whether mutational activation of Hedgehog signaling drives T-cell transformation is unknown, hindering the rationale for therapeutic intervention. Here, we show that Hedgehog pathway mutations predict chemotherapy resistance in human T-ALL, and drive oncogenic transformation in a zebrafish model of the disease. We found Hedgehog pathway mutations in 16% of 109 childhood T-ALL cases, most commonly affecting its negative regulator PTCH1. Hedgehog mutations were associated with resistance to induction chemotherapy (P = 0.009). Transduction of wild-type PTCH1 into PTCH1-mutant T-ALL cells induced apoptosis (P = 0.005), a phenotype that was reversed by downstream Hedgehog pathway activation (P = 0.007). Transduction of most mutant PTCH1, SUFU, and GLI alleles into mammalian cells induced aberrant regulation of Hedgehog signaling, indicating that these mutations are pathogenic. Using a CRISPR/Cas9 system for lineage-restricted gene disruption in transgenic zebrafish, we found that ptch1 mutations accelerated the onset of notch1-induced T-ALL (P = 0.0001), and pharmacologic Hedgehog pathway inhibition had therapeutic activity. Thus, Hedgehog-activating mutations are driver oncogenic alterations in high-risk T-ALL, providing a molecular rationale for targeted therapy in this disease

Virtual coupling of pyran protons in the 1H NMR spectra of C- and N-glucoronides: Dependence on substitution and solvent

We have observed that certain C-and N-glucuronides prepared as intermediates for breast cancer preventives demonstrate non-first order 1H NMR spectra that are not the result of impurities or degradation but are instead due to virtual coupling in the pyran proton network. This virtual coupling shows the expected dependence on solvent and field strength and, more importantly, on the nature of the C-1 substitution. Although the hybridization of the atom bonded to C-1 may play a role, it appears that steric and/or electronic factors, which have the effect of increasing Δv/J for H-3 and H-4, are critical for eliminating the spectral complexity. These observations, which appear to be fairly general, suggest that this phenomenon should be considered when addressing the purity of pharmaceutical agents containing these types of structural units

Structure–Activity Relationships and Mechanism of Action of Small Molecule Smoothened Modulators Discovered by High-Throughput Screening and Rational Design

Smoothened (Smo) is the signal transducer of the Hedgehog (Hh) pathway and its stimulation or inhibition is considered a potential powerful tool in regenerative medicine and for the treatment of cancer. In the last years, many natural and nonnatural small molecules have been identified that are able to modulate the Hh pathway. Most of them target Smo, while only a few compounds are able to interact directly with upstream and downstream Hh pathway components. Although several compounds showed a remarkable potency and selectivity, their use induced emergence of mutated and resistant cell lines. In an attempt to find new chemical entries able to affect the Hh pathway and overcome limitation imposed by mutations and resistance, academic researchers and pharmaceutical companies are making further efforts to identify new drug-like small molecules to be included in the currently available therapeutic protocols for several types of cancers or in regenerative medicine and tissue repair