Most anaplastic lymphoma kinase (ALK)–positive non–small cell lung cancers (NSCLCs) are highly responsive to treatment with ALK tyrosine kinase inhibitors (TKIs). However, patients with these cancers invariably relapse, typically within 1 year, because of the development of drug resistance. Herein, we report findings from a series of lung cancer patients (n = 18) with acquired resistance to the ALK TKI crizotinib. In about one-fourth of patients, we identified a diverse array of secondary mutations distributed throughout the ALK TK domain, including new resistance mutations located in the solvent-exposed region of the adenosine triphosphate–binding pocket, as well as amplification of the ALK fusion gene. Next-generation ALK inhibitors, developed to overcome crizotinib resistance, had differing potencies against specific resistance mutations. In addition to secondary ALK mutations and ALK gene amplification, we also identified aberrant activation of other kinases including marked amplification of KIT and increased autophosphorylation of epidermal growth factor receptor in drug-resistant tumors from patients. In a subset of patients, we found evidence of multiple resistance mechanisms developing simultaneously. These results highlight the unique features of TKI resistance in ALK-positive NSCLCs and provide the rationale for pursuing combinatorial therapeutics that are tailored to the precise resistance mechanisms identified in patients who relapse on crizotinib treatment.

The ability of molecular docking, using the program Glide and an MM-GBSA postdocking scoring protocol, to correctly rank a number of congeneric kinase inhibitors was assessed. The approach was successful for the cases considered and suggests that this may be useful for the design of inhibitors in the lead optimization phase of drug discovery.

Purpose: Cyclin-dependent kinase 9 (CDK9) is a transcriptional regulator and potential therapeutic target for many cancers. Multiple nonselective CDK9 inhibitors have progressed clinically but were limited by a narrow therapeutic window. This work describes a novel, potent, and highly selective CDK9 inhibitor, AZD4573. Experimental Design: The antitumor activity of AZD4573 was determined across broad cancer cell line panels in vitro as well as cell line-and patient-derived xenograft models in vivo. Multiple approaches, including integrated transcriptomic and proteomic analyses, loss-of-function pathway interrogation, and pharmacologic comparisons, were employed to further understand the major mechanism driving AZD4573 activity and to establish an exposure/ effect relationship. Results: AZD4573 is a highly selective and potent CDK9 inhibitor. It demonstrated rapid induction of apoptosis and subsequent cell death broadly across hematologic cancer models in vitro, and MCL-1 depletion in a dose-and time-dependent manner was identified as a major mechanism through which AZD4573 induces cell death in tumor cells. This pharmacodynamic (PD) response was also observed in vivo, which led to regressions in both subcutaneous tumor xenografts and disseminated models at tolerated doses both as monotherapy or in combination with venetoclax. This understanding of the mechanism, exposure, and antitumor activity of AZD4573 facilitated development of a robust pharmacokinetic/PD/efficacy model used to inform the clinical trial design. Conclusions: Selective targeting of CDK9 enables the indirect inhibition of MCL-1, providing a therapeutic option for MCL-1dependent diseases. Accordingly, AZD4573 is currently being evaluated in a phase I clinical trial for patients with hematologic malignancies (clinicaltrials.gov identifier: NCT03263637). See related commentary by Alcon et al., p. 761

Transforming growth factor-β activated kinase-1 (TAK1) is a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family that regulates several signaling pathways including NF-κB signal transduction and p38 activation. TAK1 deregulation has been implicated in human diseases including cancer and inflammation. Here, we show that, in addition to its kinase activity, TAK1 has intrinsic ATPase activity, that (5Z)-7-Oxozeaenol irreversibly inhibits TAK1, and that sensitivity to (5Z)-7-Oxozeaenol inhibition in hematological cancer cell lines is NRAS mutation status and TAK1 pathway dependent. X-ray crystallographic and mass spectrometric studies showed that (5Z)-7-Oxozeaenol forms a covalent complex with TAK1. Detailed biochemical characterization revealed that (5Z)-7-Oxozeaenol inhibited both the kinase and the ATPase activity of TAK1 following a bi-phase kinetics, consistent with the irreversible inhibition mechanism. In DoHH2 cells, (5Z)-7-Oxozeaenol potently inhibited the p38 phosphorylation driven by TAK1, and the inhibition lasted over 6 h after withdrawal of (5Z)-7-Oxozeaenol. Profiling (5Z)-7-Oxozeaenol in a panel of hematological cancer cells showed that sensitive cell lines tended to carry NRAS mutations and that genes in TAK1 regulated pathways were enriched in sensitive cell lines. Taken together, we have elucidated the molecular mechanism of a TAK1 irreversible inhibitor and laid the foundation for designing next generation TAK1 irreversible inhibitors. The NRAS-TAK1-Wnt signaling network discerned in our study may prove to be useful in patient selection for TAK1 targeted agents in hematological cancers.

High-level ab initio methods based on the coupled cluster approximation have been used to study properties of several isomers of the C5H radical, a molecule of significant interest in radioastronomy. The three lowest-lying isomers [the well-known linear form (1) as well as two ring-chain structures, HC2C3 (2) and C2C3H (3)] lie within 30 kcal/mol with isomer 2 approximately 5 kcal/mol higher than the lowest-energy isomer 1. The computed rotational constant for the linear isomer is within 0.7% of the value determined in previous experimental analyses. Transition states formed via simple ring-opening mechanisms for the interconversion of the linear and ring-chain isomers have also been located; these lie ca. 27 and 31 kcal/mol above isomers 2 and 3, respectively, indicating reasonable kinetic stability of these structures to isomerization. The computed rotational constants for these isomers should be useful for laboratory and astronomical observation of these species. In addition, four other minimum-energy structures are found to lie somewhat higher in energy. These isomers involve both three- and four-membered carbon rings, as well as a bent-chain structure.

Dual Bcl-2/Bcl-xL inhibitors are expected to deliver therapeutic benefit in many haematological and solid malignancies, however, their use is limited by tolerability issues. AZD4320, a potent dual Bcl-2/Bcl-xL inhibitor, has shown good efficacy however had dose limiting cardiovascular toxicity in preclinical species, coupled with challenging physicochemical properties, which prevented its clinical development. Here, we describe the design and development of AZD0466, a drug-dendrimer conjugate, where AZD4320 is chemically conjugated to a PEGylated poly-lysine dendrimer. Mathematical modelling was employed to determine the optimal release rate of the drug from the dendrimer for maximal therapeutic index in terms of preclinical anti-tumour efficacy and cardiovascular tolerability. The optimised candidate is shown to be efficacious and better tolerated in preclinical models compared with AZD4320 alone. The AZD4320-dendrimer conjugate (AZD0466) identified, through mathematical modelling, has resulted in an improved therapeutic index and thus enabled progression of this promising dual Bcl-2/Bcl-xL inhibitor into clinical development.

A series of dimeric compounds based on the AVPI motif of Smac were designed and prepared as antagonists of the inhibitor of apoptosis proteins (IAPs). Optimization of cellular potency, physical properties, and pharmacokinetic parameters led to the identification of compound 14 (AZD5582), which binds potently to the BIR3 domains of cIAP1, cIAP2, and XIAP (IC50 = 15, 21, and 15 nM, respectively). This compound causes cIAP1 degradation and induces apoptosis in the MDA-MB-231 breast cancer cell line at subnanomolar concentrations in vitro. When administered intravenously to MDA-MB-231 xenograft-bearing mice, 14 results in cIAP1 degradation and caspase-3 cleavage within tumor cells and causes substantial tumor regressions following two weekly doses of 3.0 mg/kg. Antiproliferative effects are observed with 14 in only a small subset of the over 200 cancer cell lines examined, consistent with other published IAP inhibitors. As a result of its in vitro and in vivo profile, 14 was nominated as a candidate for clinical development.

Articles you may be interested inComplex absorbing potential based equation-of-motion coupled cluster method for the potential energy curve of CO 2 − anion De-perturbative corrections for charge-stabilized double ionization potential equation-of-motion coupled-cluster method J. Chem. Phys. 136, 244109 (2012); 10.1063/1.4730296 Different equation-of-motion coupled cluster methods with different reference functions: The formyl radicalActive-space symmetry-adapted-cluster configuration-interaction and equation-of-motion coupled-cluster methods for high accuracy calculations of potential energy surfaces of radicals A method proposed some time ago to correct for residual correlation effects within the framework of equation-of-motion coupled-cluster theory for ionized states in the singles and doubles approximation ͑EOMIP-CCSD͒ is discussed, and a minor modification is suggested that provides a more balanced theoretical treatment. The resulting approach is used to calculate properties of diatomic radicals, where comparison with experiment and other high-level calculations is straightforward. In addition, two electronic states of NO 2 and the ground state of the cyclic C 3 H molecule are studied, cases in which symmetry-breaking phenomena play an important role. Results indicate that EOMIP-CCSD* generally provides a systematic improvement relative to the uncorrected EOMIP-CCSD approach for predicting properties of radicals.