RESUMO
Cholangiocarcinoma (CCA), an aggressive biliary tract cancer, carries a grim prognosis with a 5-year survival rate of 5%-15%. Standard chemotherapy regimens for CCA, gemcitabine plus cisplatin (GemCis) or its recently approved combination with durvalumab demonstrate dismal clinical activity, yielding a median survival of 12-14 months. Increased serotonin accumulation and secretion have been implicated in the oncogenic activity of CCA. This study investigated the therapeutic efficacy of telotristat ethyl (TE), a tryptophan hydroxylase inhibitor blocking serotonin biosynthesis, in combination with standard chemotherapies in preclinical CCA models. Nab-paclitaxel (NPT) significantly enhanced animal survival (60%), surpassing the marginal effects of TE (11%) or GemCis (9%) in peritoneal dissemination xenografts. Combining TE with GemCis (26%) or NPT (68%) further increased survival rates. In intrahepatic (iCCA), distal (dCCA) and perihilar (pCCA) subcutaneous xenografts, TE exhibited substantial tumour growth inhibition (41%-53%) compared to NPT (56%-69%) or GemCis (37%-58%). The combination of TE with chemotherapy demonstrated enhanced tumour growth inhibition in all three cell-derived xenografts (67%-90%). PDX studies revealed TE's marked inhibition of tumour growth (40%-73%) compared to GemCis (80%-86%) or NPT (57%-76%). Again, combining TE with chemotherapy exhibited an additive effect. Tumour cell proliferation reduction aligned with tumour growth inhibition in all CDX and PDX tumours. Furthermore, TE treatment consistently decreased serotonin levels in all tumours under all therapeutic conditions. This investigation decisively demonstrated the antitumor efficacy of TE across a spectrum of CCA preclinical models, suggesting that combination therapies involving TE, particularly for patients exhibiting serotonin overexpression, hold the promise of improving clinical CCA therapy.
Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Triptofano Hidroxilase , Ensaios Antitumorais Modelo de Xenoenxerto , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/patologia , Colangiocarcinoma/metabolismo , Animais , Triptofano Hidroxilase/metabolismo , Triptofano Hidroxilase/antagonistas & inibidores , Humanos , Linhagem Celular Tumoral , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/patologia , Neoplasias dos Ductos Biliares/metabolismo , Camundongos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico , Proliferação de Células/efeitos dos fármacos , Gencitabina , Cisplatino/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Sinergismo Farmacológico , Modelos Animais de Doenças , Serotonina/metabolismo , FemininoRESUMO
Kirsten rat sarcoma viral oncogene homolog (KRAS) is one of the most frequently mutated oncogenes in solid tumors. More than 90% of pancreatic ductal adenocarcinoma (PDAC) are driven by mutations in the KRAS gene, suggesting the importance of targeting this oncogene in PDAC. Initial efforts to target KRAS have been unsuccessful due to its small size, high affinity for guanosine triphosphate/guanosine diphosphate, and lack of distinct drugbinding pockets. Therefore, much of the focus has been directed at inhibiting the activation of major signaling pathways downstream of KRAS, most notably the PI3K/AKT and RAF/MAPK pathways, using tyrosine kinase inhibitors and monoclonal antibodies. While preclinical studies showed promising results, clinical data using the inhibitors alone and in combination with other standard therapies have shown limited practicality, largely due to the lack of efficacy and doselimiting toxicities. Recent therapeutic approaches for KRASdriven tumors focus on mutationspecific drugs such as selective KRASG12C inhibitors and son of sevenless 1 panKRAS inhibitors. While KRASG12C inhibitors showed great promise against patients with nonsmall cell lung cancer (NSCLC) harboring KRASG12C mutations, they were not efficacious in PDAC largely because the major KRAS mutant isoforms in PDAC are G12D, G12V, and G12R. As a result, KRASG12D and panKRAS inhibitors are currently under investigation as potential therapeutic options for PDAC. The present review summarized the importance of KRAS oncogenic signaling, challenges in its targeting, and preclinical and clinical targeted agents including recent direct KRAS inhibitors for blocking KRAS signaling in PDAC.