RESUMEN
Genomic analyses of cancer have identified recurrent point mutations in the RNA splicing factor-encoding genes SF3B1, U2AF1, and SRSF2 that confer an alteration of function. Cancer cells bearing these mutations are preferentially dependent on wild-type (WT) spliceosome function, but clinically relevant means to therapeutically target the spliceosome do not currently exist. Here we describe an orally available modulator of the SF3b complex, H3B-8800, which potently and preferentially kills spliceosome-mutant epithelial and hematologic tumor cells. These killing effects of H3B-8800 are due to its direct interaction with the SF3b complex, as evidenced by loss of H3B-8800 activity in drug-resistant cells bearing mutations in genes encoding SF3b components. Although H3B-8800 modulates WT and mutant spliceosome activity, the preferential killing of spliceosome-mutant cells is due to retention of short, GC-rich introns, which are enriched for genes encoding spliceosome components. These data demonstrate the therapeutic potential of splicing modulation in spliceosome-mutant cancers.
Asunto(s)
Neoplasias/tratamiento farmacológico , Neoplasias/genética , Piperazinas/farmacología , Piridinas/farmacología , Empalme del ARN/genética , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Empalmosomas/genética , Administración Oral , Animales , Secuencia de Bases , Humanos , Intrones/genética , Células K562 , Leucemia/genética , Leucemia/patología , Ratones , Mutación , Neoplasias/patología , Piperazinas/administración & dosificación , Piridinas/administración & dosificación , Empalme del ARN/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Bibliotecas de Moléculas Pequeñas/farmacología , Carga Tumoral , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Recurrent mutations in the spliceosome are observed in several human cancers, but their functional and therapeutic significance remains elusive. SF3B1, the most frequently mutated component of the spliceosome in cancer, is involved in the recognition of the branch point sequence (BPS) during selection of the 3' splice site (ss) in RNA splicing. Here, we report that common and tumor-specific splicing aberrations are induced by SF3B1 mutations and establish aberrant 3' ss selection as the most frequent splicing defect. Strikingly, mutant SF3B1 utilizes a BPS that differs from that used by wild-type SF3B1 and requires the canonical 3' ss to enable aberrant splicing during the second step. Approximately 50% of the aberrantly spliced mRNAs are subjected to nonsense-mediated decay resulting in downregulation of gene and protein expression. These findings ascribe functional significance to the consequences of SF3B1 mutations in cancer.
Asunto(s)
Empalme Alternativo , Mutación , Neoplasias/genética , Fosfoproteínas/genética , Ribonucleoproteína Nuclear Pequeña U2/genética , Alelos , Secuencia de Aminoácidos , Secuencia de Bases , Células HEK293 , Humanos , Datos de Secuencia Molecular , Tasa de Mutación , Degradación de ARNm Mediada por Codón sin Sentido , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Factores de Empalme de ARN , Ribonucleoproteína Nuclear Pequeña U2/química , Ribonucleoproteína Nuclear Pequeña U2/metabolismoRESUMEN
A total synthesis of the natural product 6-deoxypladienolide D (1) has been achieved. Two noteworthy attributes of the synthesis are (1) a late-stage allylic oxidation which proceeds with full chemo-, regio-, and diastereoselectivity and (2) the development of a scalable and cost-effective synthetic route to support drug discovery efforts. 6-Deoxypladienolide D (1) demonstrates potent growth inhibition in a mutant SF3B1 cancer cell line, high binding affinity to the SF3b complex, and inhibition of pre-mRNA splicing.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Línea Celular Tumoral/química , Línea Celular Tumoral/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Compuestos Epoxi/síntesis química , Compuestos Epoxi/metabolismo , Macrólidos/síntesis química , Macrólidos/metabolismo , Fosfoproteínas/antagonistas & inhibidores , Fosfoproteínas/química , Empalme del ARN/efectos de los fármacos , Ribonucleoproteína Nuclear Pequeña U2/antagonistas & inhibidores , Ribonucleoproteína Nuclear Pequeña U2/química , Antineoplásicos/química , Sitios de Unión , Compuestos Epoxi/química , Humanos , Macrólidos/química , Factores de Empalme de ARNRESUMEN
The total synthesis of kalihinol C, a bis-isonitrile marine diterpenoid isolated from Acanthella sp., is reported. The decalin framework was established via an intramolecular Diels-Alder cycloaddition and subsequently functionalized through a series of substrate-controlled diastereoselective transformations to install the tertiary isonitrile, beta-hydroxy isonitrile, and pendant tetrahydrofuranyl ring.
