RESUMEN
WRN helicase is a promising target for treatment of cancers with microsatellite instability (MSI) due to its essential role in resolving deleterious non-canonical DNA structures that accumulate in cells with faulty mismatch repair mechanisms1-5. Currently there are no approved drugs directly targeting human DNA or RNA helicases, in part owing to the challenging nature of developing potent and selective compounds to this class of proteins. Here we describe the chemoproteomics-enabled discovery of a clinical-stage, covalent allosteric inhibitor of WRN, VVD-133214. This compound selectively engages a cysteine (C727) located in a region of the helicase domain subject to interdomain movement during DNA unwinding. VVD-133214 binds WRN protein cooperatively with nucleotide and stabilizes compact conformations lacking the dynamic flexibility necessary for proper helicase function, resulting in widespread double-stranded DNA breaks, nuclear swelling and cell death in MSI-high (MSI-H), but not in microsatellite-stable, cells. The compound was well tolerated in mice and led to robust tumour regression in multiple MSI-H colorectal cancer cell lines and patient-derived xenograft models. Our work shows an allosteric approach for inhibition of WRN function that circumvents competition from an endogenous ATP cofactor in cancer cells, and designates VVD-133214 as a promising drug candidate for patients with MSI-H cancers.
Asunto(s)
Regulación Alostérica , Descubrimiento de Drogas , Inhibidores Enzimáticos , Proteómica , Helicasa del Síndrome de Werner , Animales , Femenino , Humanos , Masculino , Ratones , Regulación Alostérica/efectos de los fármacos , Línea Celular Tumoral , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/enzimología , Neoplasias Colorrectales/patología , Cisteína/efectos de los fármacos , Cisteína/metabolismo , Roturas del ADN de Doble Cadena/efectos de los fármacos , Descubrimiento de Drogas/métodos , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/química , Inestabilidad de Microsatélites , Modelos Moleculares , Helicasa del Síndrome de Werner/antagonistas & inhibidores , Helicasa del Síndrome de Werner/química , Helicasa del Síndrome de Werner/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Muerte Celular/efectos de los fármacos , Adenosina Trifosfato/metabolismoRESUMEN
BACKGROUND: Cervical cancer (CC) is a viral-associated tumor caused by the infection with the human papilloma virus. CC is then an immunogenic cancer that expresses viral antigens. Despite being immunogenic, CC does not fully respond to immune checkpoint inhibitors (ICI). LIF is a crucial cytokine in embryo implantation, involved in maternal tolerance that acts as an immunomodulatory factor in cancer. LIF is expressed in CC and high levels of LIF is associated with poor prognosis in CC. METHODS: We evaluated the impact of LIF on the immune response to ICI using primary plasmocytoid dendritic cells (pDCs) and macrophage cultures, syngeneic animals and patient-derived models that recapitulate the human tumor microenvironment. RESULTS: We found that the viral proteins E6 and E7 induce the expression of LIF via the NFκB pathway. The secreted LIF can then repress type I interferon expressed in pDCs, and CXCL9 expressed in tumor associated macrophages. Blockade of LIF promotes the induction of type I interferon and CXCL9 inducing the tumor infiltration of CD8 T cell. This results in the sensitization of the tumor to ICI. Importantly, we observed that patients with CC expressing high levels of LIF tent to be resistant to ICI. CONCLUSION: Our data show that the HPV virus induces the expression of LIF to provide a selective advantage to the tumor cell by generating local immunosuppression via the repression of type I interferon and CXCL9. Combinatory treatment with blocking antibodies against LIF and ICI could be effective against CC expressing high levels of LIF.