Establishment of a human primary pancreatic cancer mouse model to examine and investigate gemcitabine resistance

Abstract

Pancreatic cancer is one of the most fatal types of cancer and is associated with a dismal prognosis. Gemcitabine-based chemotherapy is clinically used for the treatment of advanced pancreatic cancer. However, many forms of pancreatic cancer have acquired resistance to gemcitabine. In order to prevent patients from suffering from the side effects of chemotherapy and to have the chance to receive more effective intervention, assessment of whether the patient pancreatic cancer cells are resistant to gemcitabine before clinical practice is crucial. Recently, patient-derived xenograft (PDX) models have been regarded as a practical approach for preclinical drug resistance test. In the present study, we harvested tumor specimens from 28 pancreatic cancer patients to establish PDX models. The tumor formation rate of the xenografts was 100%, several of which could be re-implanted in nude mice for more than 10 passages. Primary cells were further obtained from the PDX xenografts to determine their morphological features and evaluate their proliferation rate, migration capacity and angiopoietic ability. In addition, the sensitivities of the primary cells and PDX xenografts to gemcitabine were correlated with each other. When compared to the gemcitabine-sensitive cells, the gemcitabine-resistant cells had a higher level of MCF2L expression, suggesting that MCF2L plays an important role in gemcitabine resistance.

DNA Methylation Clusters and Their Relation to Cytogenetic Features in Pediatric AML

“…Patients with t(8;21) demonstrated overall hypomethylation as compared to other groups, with all of the top 50 probes (mapping to 44 unique genes) significantly hypo-methylated as compared to non t(8;21) cases ( Table 2 ). These genes included MCF2L , a guanine nucleotide exchange factor implicated in gemcitabine resistance that also impacts Rho/Rac signaling [ 35 ]; SLC9A1 , involved in maintaining alkaline pH and Warburg effect and associated with chemo-resistance in solid tumors; FAM120B located in close proximity to MLLT4 , a known fusion partner in leukemia; DZIP1 , zinc finger protein 1, an oncogene involved in wnt/B catenin and Hedgehog signaling; genes with potential tumor suppressive effects; PTPRF that acts via deactivating ERK1/2 signaling; LARP1 that interacts with oncogenic transcripts and regulates mTOR post-transcriptionally with impact on CDK9 and mTOR interaction in leukemia [ 36 ]. A few selected examples from the t(8:21) specific paired methylation and expression signatures, are shown in Figure 3 panels A and B ( Table S3 shows the detailed results).…”

Comprehensive analysis and establishment of a prediction model of alternative splicing events reveal the prognostic predictor and immune microenvironment signatures in triple negative breast cancer

“…MC2L is one of the guanine nucleotide exchange factors, which may link the potential signalling pathway through RAC1, RHOA and CDC42, also named DBS/DBLs Big Sister, belonging to the DBL family [ 39 ]. Research has shown that MCF2L/DBS MCF2L may play an important role in gemcitabine resistance of primary pancreatic cancer patients [ 40 ], which may provide some explanations for the causes of TNBC chemotherapy resistance. It should be noted that the EPB41 gene encodes Erythrocyte Membrane Protein Band 4.1, which belongs to the family of cytoskeletal proteins that play important roles in maintaining normal cell morphology and cell adhesion, migration, division, and intercellular signalling [ 41 – 43 ].…”

Desenvolvimento de xenotransplantes de tumores pancreáticos humanos para varredura genética de alvos moleculares com potencial terapêutico

“…Para além da pesquisa básica e pré-clínica, existe também a perspectiva de aplicação clínica dos PDXs na elaboração de estratégias terapêuticas personalizadas, nas quais atuariam como avatares dos pacientes para o teste e seleção do melhor regime de tratamento (Jin et al, 2010b;Hidalgo et al, 2011;Villarroel et al, 2011;Kamiyama et al, 2013;Malaney et al, 2014;Witkiewicz et al, 2016;Cheng et al, 2017;Dong et al, 2017;Perales-Patón et al, 2017;Williams, 2017). Por outro lado, embora representem um novo e valioso instrumento no arsenal dos pesquisadores na guerra contra o câncer, os PDXs não são modelos perfeitos e também apresentam as suas limitações (Kelland, 2004;Kopetz et al, 2012;Choi et al, 2014;Hidalgo et al, 2014;Byrne et al, 2017;Cheng et al, 2017;Dong et al, 2017;Lin et al, 2017a;Wen et al, 2017;Williams, 2018). Por exemplo, o estabelecimento dos xenotransplantes nem sempre é bem sucedido, havendo taxas de sucesso significativamente baixas para determinados tipos de câncer, o que se configura como um obstáculo importante à sua eventual aplicação em medicina personalizada (Hidalgo et al, 2014;Dong et al, 2017).…”

“…Como exemplo, a gradual substituição do estroma humano pelo estroma murino ao longo das passagens pode afetar o efeito de drogas dirigidas contra esse componente do tumor, como é o caso dos agentes antiangiogênicos (Kelland, 2004;Kopetz et al, 2012;Hidalgo et al, 2014;Cassidy et al, 2015;Byrne et al, 2017;Wen et al, 2017;Williams, 2018). De modo semelhante, o comprometimento do sistema imunológico nos camundongos receptores torna os PDXs incapazes de recapitular com precisão as complexas interações entre as células neoplásicas e as células imunes, restringindo assim a avaliação de terapias com agentes imunomoduladores (Choi et al, 2014;Hidalgo et al, 2014;Cassidy et al, 2015;Byrne et al, 2017;Cheng et al, 2017;Wen et al, 2017;Williams, 2018). Outro inconveniente que pode causar equívocos nas conclusões acerca do efeito de medicamentos é o fato de que PDXs gerados a partir de tumores resistentes à terapia podem eventualmente perder essa característica, e se tornar novamente suscetíveis (Sereti et al, 2018).…”

“…Apesar dessas limitações, o uso dos PDXs emerge como um instrumento com grande potencial para avançar o conhecimento sobre a patogênese do câncer e permitir o exame de abordagens inovadoras para o cuidado dos pacientes. Na oncologia pancreática, em específico, um número crescente de publicações tem mostrado a expansão das aplicações desse modelo (Sereti et al, 2018), sobretudo para a identificação de biomarcadores prognósticos (Jimeno et al, , 2010Garrido-Laguna et al, 2011;Torphy et al, 2014;Duconseil et al, 2015;Bian et al, 2017), investigação de mecanismos de resistência (Kim et al, 2012;Noll et al, 2016;Zhang et al, 2017;Golan et al, 2018) e na avaliação de novos regimes terapêuticos, frequentemente baseados no reposicionamento de drogas (Laheru et al, 2012;Walters et al, 2013b;Gayet et al, 2015;Hiroshima et al, 2015;Witkiewicz et al, 2015a;Nicolle et al, 2017;Rajeshkumar et al, 2017;Chou et al, 2018;Kawaguchi et al, 2018ab Paradise et al, 2018). Diversos estudos identificaram perfis anormais de metilação do DNA, particularmente associados à inativação de genes supressores de tumor, e sugerem que essas alterações seriam eventos precoces na oncogênese pancreática, se intensificando ao longo da progressão da doença (Ueki et al, 2000(Ueki et al, , 2001Fukushima et al, 2002;Sato et al, 2003ab;Hagihara et al, 2004;Matsubayashi et al, 2006;Omura et al, 2008;Sato et al, 2008;Tan et al, 2009;Shimizu et al, 2011;Vincent et al, 2011b;Nones et al, 2014).…”