Cdc7 is an essential kinase that promotes DNA replication by activating origins of replication. Here, we characterized the potent Cdc7 inhibitor PHA-767491 (1) in biochemical and cell-based assays, and we tested its antitumor activity in rodents. We found that the compound blocks DNA synthesis and affects the phosphorylation of the replicative DNA helicase at Cdc7-dependent phosphorylation sites. Unlike current DNA synthesis inhibitors, PHA-767491 prevents the activation of replication origins but does not impede replication fork progression, and it does not trigger a sustained DNA damage response. Treatment with PHA-767491 results in apoptotic cell death in multiple cancer cell types and tumor growth inhibition in preclinical cancer models. To our knowledge, PHA-767491 is the first molecule that directly affects the mechanisms controlling initiation as opposed to elongation in DNA replication, and its activities suggest that Cdc7 kinase inhibition could be a new strategy for the development of anticancer therapeutics.

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase responsible for the development of different tumor types. Despite the remarkable clinical activity of crizotinib (Xalkori), the first ALK inhibitor approved in 2011, the emergence of resistance mutations and of brain metastases frequently causes relapse in patients. Within our ALK drug discovery program, we identified compound 1, a novel 3-aminoindazole active on ALK in biochemical and in cellular assays. Its optimization led to compound 2 (entrectinib), a potent orally available ALK inhibitor active on ALK-dependent cell lines, efficiently penetrant the blood-brain barrier (BBB) in different animal species and highly efficacious in in vivo xenograft models. Moreover, entrectinib resulted to be strictly potent on the closely related tyrosine kinases ROS1 and TRKs recently found constitutively activated in several tumor types. Entrectinib is currently undergoing phase I/II clinical trial for the treatment of patients affected by ALK-, ROS1-, and TRK-positive tumors.

Prodigiosins (Ps) represent a family of naturally occurring red pigments characterized by a common pyrrolylpyrromethene skeleton. Some members of this family have been shown to possess interesting immunosuppressive properties exerted with a novel mechanism of action, different from that of currently used drugs. In fact, Ps inhibit phosphorylation and activation of JAK-3, a cytoplasmic tyrosine kinase associated with a cell surface receptor component called common gamma-chain, which is exclusive of all IL-2 cytokine family receptors. Blocking common gamma-chain transduction activity results in a potent and specific immunosuppressive activity. With respect to the interesting and unexploited immunomodulating properties of this family of compounds we initiated a medicinal chemistry program aimed at finding novel prodigiosin derivatives with improved immunosuppressive activity and lower toxicity. Utilizing an unprecedented and flexible way of assembling the prodigiosin frame, a number of new derivatives have been prepared and tested leading to the choice of 4-benzyloxy-5-[(5-undecyl-2H-pyrrol-2-ylidene)methyl]-2, 2'-bi-1H-pyrrole (PNU-156804, 16) as a lead immunosuppressant.

A new model of 4-alkyl-1-arylpiperazines containing a terminal dihydronaphthalene fragment on the alkyl chain was synthesized in order to have mixed serotonergic and dopaminergic activity and to pursue the recent alternative approaches to the discovery of novel antipsychotic and anxiolytic agents. Title compounds were evaluated for in vitro activity on dopamine D-2 and serotonin ~-H T~A and 5-HTz receptors by radioreceptor binding assays. They show high nanomolar affiiity for ~-H T~A , moderate affinity for D-2, and low affinity for 5-HTz receptors, and in particular, two compounds, 4-[3-( 1,2-dihydro-6-methoxynaphthalen-4-yl)-n-propyll-1-(2-methoxyphenyl)piperazine (8) and 4-[3-( 1,2-dihydro-8-methoxynaphthalen-4-yl)-n-propyll-l-(2-pyridyl)piperazine (E), show values (nM) of ICs0 = 2.0 and 1.4 for ~-H T~A and ICs0 = 90.6 and 119.3 for D-2, respectively.Some in vivo behavioral studies show compound 8 to be an antagonist on ~-H T~A receptors. These first findings place the new arylpiperazines on the same level as that of the azaspirone class, e.g., and buspirone. 1-(2-methoxypheny1)-4-[4-(2-phthalimido)-n-butyl]piperazineCommon chlorpromazine-like antipsychotic drugs produce extrapyramidal symptoms (EPS), while antianxiety agents, such as benzodiazepines, present ataxia, sedative phenomena, and signs of drug dependence as side effects.Recent observationslJ indicate that improvement of these agents may be attained by combining dopaminergic and serotonergic activities in a single structure. Indeed, at the moment, there is considerable interest in molecules with multireceptorial activity3 as novel antipsychotic agents of potential clinical significance.Within this context, examples of compounds having both D-2 and 5-HTz receptor antagonist properties are setoperone4 and risperidone:b which have been evaluated in clinical trials, as well as new molecules which are predicted to be efficacious against negative symptoms of schizophrenia and to have fewer EPS.' Another example of an atypical neuroleptic drug with reduced side effects is clozapine which, in addition to acting on a specific subclass of dopamine receptors,8 interacts with significant affinity on a broad range of receptor types (serotonergic, adrenergic, muscarinic, a n d histaminergic).B-12Formerly, in our laboratories, we have synthesized compounds such as the l-aminoethylheterotetralin13J4 derivatives 1, which show no affinity for dopaminergic and serotonergic receptors, although they are open derivatives of active cyclic structures on DA and 5-HT receptors.In order to achieve this dual affinity for these receptors, we inserted the terminal nitrogen of the side chain of compounds 1 in an arylpiperazine structure. During the last decade, the arylpiperazine moiety has shown to be one of the templates for 5-HT activity,16 but minor Abstract published in Advance ACS Abstracts, December 15,1993. 1 : R --NE-2 : R --N 7 L N -Aryl modifications involve significant changes in affinity and selectivity, since it can also display moderate to high affinity for DA rece...

Cdc7 kinase is an essential protein that promotes DNA replication in eukaryotic organisms. Genetic evidence indicates that Cdc7 inhibition can cause selective tumor-cell death in a p53-independent manner, supporting the rationale for developing Cdc7 small-molecule inhibitors for the treatment of cancers. In this paper, the synthesis and structure-activity relationships of 2-heteroaryl-pyrrolopyridinones, the first potent Cdc7 kinase inhibitors, are described. Starting from 2-pyridin-4-yl-1,5,6,7-tetrahydro-pyrrolo[3,2-c]pyridin-4-one, progress toward a simple scaffold, tailored for Cdc7 inhibition, is reported.