Inhibitors of histone acetyltransferases KAT6A/B induce senescence and arrest tumour growth.

Acetylation of histones by lysine acetyltransferases (KATs) is essential for chromatin organization and function1. Among the genes coding for the MYST family of KATs (KAT5-KAT8) are the oncogenes KAT6A (also known as MOZ) and KAT6B (also known as MORF and QKF)2,3. KAT6A has essential roles in normal haematopoietic stem cells4-6 and is the target of recurrent chromosomal translocations, causing acute myeloid leukaemia7,8. Similarly, chromosomal translocations in KAT6B have been identified in diverse cancers8. KAT6A suppresses cellular senescence through the regulation of suppressors of the CDKN2A locus9,10, a function that requires its KAT activity10. Loss of one allele of KAT6A extends the median survival of mice with MYC-induced lymphoma from 105 to 413 days11. These findings suggest that inhibition of KAT6A and KAT6B may provide a therapeutic benefit in cancer. Here we present highly potent, selective inhibitors of KAT6A and KAT6B, denoted WM-8014 and WM-1119. Biochemical and structural studies demonstrate that these compounds are reversible competitors of acetyl coenzyme A and inhibit MYST-catalysed histone acetylation. WM-8014 and WM-1119 induce cell cycle exit and cellular senescence without causing DNA damage. Senescence is INK4A/ARF-dependent and is accompanied by changes in gene expression that are typical of loss of KAT6A function. WM-8014 potentiates oncogene-induced senescence in vitro and in a zebrafish model of hepatocellular carcinoma. WM-1119, which has increased bioavailability, arrests the progression of lymphoma in mice. We anticipate that this class of inhibitors will help to accelerate the development of therapeutics that target gene transcription regulated by histone acetylation.

Perforated appendicitis with endosalpingiosis.

Endosalpingiosis a condition of ectopic glandular epithelium diagnosed histologically, most commonly on pelvic and abdominal peritoneum, that can be associated with abdominal pain mimicking appendicitis. There is evidence emerging that endosalpingiosis may be associated with serous ovarian malignancies. Here we describe a case of perforated appendicitis with concurrent endosalpingiosis. Further research is required to better elucidate the association between endosalpingiosis and malignancy, and the implications of a concurrent presentation with a hollow viscus perforation.

A remarkable inversion of structure-activity dependence on imido N-substituents with varying co-ligand topology and the synthesis of a new borate-free zwitterionic polymerisation catalyst.

Ethylene polymerisation productivities of tris(pyrazolyl)methane-supported catalysts [Ti(NR){HC(Me2pz)3}Cl2] show a dramatically different dependence on the imido R-group compared to those of their TACN analogues, attributed to differences in fac-N3 donor topology; when treated with AliBu3, the zwitterionic tris(pyrazolyl)methide compound [Ti(N-2-C6H4tBu){C(Me2pz)3}Cl(THF)] also acts as a highly active, single site catalyst (TACN = 1,4,7-trimethyltriazacyclononane).

Discovery and evaluation of highly active imidotitanium ethylene polymerisation catalysts using high throughput catalyst screening.

A family of ca. 50 imidotitanium precatalysts [Ti(NR)(Me(3)[9]aneN(3))Cl(2)](R = alkyl or aryl; Me(3)[9]aneN(3)= 1,4,7-trimethyltriazacyclononane) were prepared in good yields using semi-automated procedures; high-throughput screening techniques identified seven highly active ethylene polymerisation precatalysts with activities in the range ca. 3 400 to 10 000 kg(PE) mol(-1) h(-1) bar(-1).

New titanium imido synthons: syntheses and supramolecular structures.

Reactions of Ti(NMe(2))(2)Cl(2) with a wide range of primary alkyl and arylamines RNH(2) afforded the corresponding 5-coordinate imido titanium compounds Ti(NR)Cl(2)(NHMe(2))(2) (R = (t)Bu (1), (i)Pr (2), CH(2)Ph (3), Ph (4), 2,6-C(6)H(3)Me(2) (5), 2,6-C(6)H(3)(i)Pr(2) (6), 2,4,6-C(6)H(2)F(3) (7), 2,3,5,6-C(6)HF(4) (8), C(6)F(5) (9), 4-C(6)H(4)Cl (10), 2,3,5,6-C(6)HCl(4) (11), 2-C(6)H(4)CF(3) (12), 2-C(6)H(4)(t)Bu (13)). The compounds 1-13 are monomeric in solution but in the solid state form either N-H...Cl hydrogen bonded dimers or chains or perfluorophenyl pi-stacked chains, depending on the imido R-group. The compound 13 was also prepared in a "one-pot" synthesis from RNH(2) and Ti(NMe(2))(4) and Me(3)SiCl. Reaction of certain Ti(NR)Cl(2)(NHMe(2))(2) compounds with an excess of pyridine afforded the corresponding bis- or tris-pyridine analogues [Ti(NR)Cl(2)(py)(x)](y) (x = 3, y = 1; x = y = 2), and the structure of Ti(2)(NC(6)F(5))(2)Cl(2)(mu-Cl)(2)(py)(4) shows pi-stacking of perfluorophenyl rings. Reaction of Ti(NMe(2))(2)Cl(2) with cross-linked aminomethyl polystyrene gave quantitative conversion to the corresponding solid-supported titanium imido complex. This paper represents the first detailed study of how supramolecular structures of imido compounds may be influenced by simple variation of the imido ligand N-substituent.