RESUMO
Authors would like to make a correction to the previous article [...].
RESUMO
Aberrant Notch and Wnt signaling are known drivers of cholangiocarcinoma (CCA), but the underlying factors that initiate and maintain these pathways are not known. Here, we show that the proline-rich homeodomain protein/hematopoietically expressed homeobox (PRH/HHEX) transcription factor forms a positive transcriptional feedback loop with Notch3 that is critical in CCA. PRH/HHEX expression is elevated in CCA, and depletion of PRH reduces CCA tumor growth in a xenograft model. Overexpression of PRH in primary human biliary epithelial cells is sufficient to increase cell proliferation and produce an invasive phenotype. Interrogation of the gene networks regulated by PRH and Notch3 reveals that unlike Notch3, PRH directly activates canonical Wnt signaling. These data indicate that hyperactivation of Notch and Wnt signaling is independent of the underlying mutational landscape and has a common origin in dysregulation of PRH. Moreover, they suggest new therapeutic options based on the dependence of specific Wnt, Notch, and CDK4/6 inhibitors on PRH activity. SIGNIFICANCE: The PRH/HHEX transcription factor is an oncogenic driver in cholangiocarcinoma that confers sensitivity to CDK4/6 inhibitors.
Assuntos
Antineoplásicos/farmacologia , Neoplasias dos Ductos Biliares/tratamento farmacológico , Colangiocarcinoma/tratamento farmacológico , Proteínas de Homeodomínio/metabolismo , Receptor Notch3/metabolismo , Fatores de Transcrição/metabolismo , Animais , Antineoplásicos/uso terapêutico , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/patologia , Ductos Biliares Intra-Hepáticos/citologia , Ductos Biliares Intra-Hepáticos/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Colangiocarcinoma/genética , Colangiocarcinoma/patologia , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Resistencia a Medicamentos Antineoplásicos/genética , Células Epiteliais , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Redes Reguladoras de Genes , Proteínas de Homeodomínio/genética , Humanos , Células K562 , Masculino , Camundongos , Mutação , Invasividade Neoplásica/genética , Piperazinas/farmacologia , Piperazinas/uso terapêutico , Cultura Primária de Células , Regiões Promotoras Genéticas , Piridinas/farmacologia , Piridinas/uso terapêutico , RNA-Seq , Fatores de Transcrição/genética , Via de Sinalização Wnt/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cholangiocarcinoma is a disease with a poor prognosis and increasing incidence and hence there is a pressing unmet clinical need for new adjuvant treatments. Protein kinase CK2 (previously casein kinase II) is a ubiquitously expressed protein kinase that is up-regulated in multiple cancer cell types. The inhibition of CK2 activity using CX-4945 (Silmitasertib) has been proposed as a novel treatment in multiple disease settings including cholangiocarcinoma. Here, we show that CX-4945 inhibited the proliferation of cholangiocarcinoma cell lines in vitro. Moreover, CX-4945 treatment induced the formation of cytosolic vacuoles in cholangiocarcinoma cell lines and other cancer cell lines. The vacuoles contained extracellular fluid and had neutral pH, features characteristic of methuosis. In contrast, simultaneous knockdown of both the α and α' catalytic subunits of protein kinase CK2 using small interfering RNA (siRNA) had little or no effect on the proliferation of cholangiocarcinoma cell lines and failed to induce the vacuole formation. Surprisingly, low doses of CX-4945 increased the invasive properties of cholangiocarcinoma cells due to an upregulation of matrix metallopeptidase 7 (MMP-7), while the knockdown of CK2 inhibited cell invasion. Our data suggest that CX-4945 inhibits cell proliferation and induces cell death via CK2-independent pathways. Moreover, the increase in cell invasion brought about by CX-4945 treatment suggests that this drug might increase tumor invasion in clinical settings.