Dataset Information

Functional and genomic characterization of patient-derived xenograft model to study the adaptation to mTORC1 inhibitor in clear cell renal cell carcinoma.

ABSTRACT: Resistance to the mechanistic target of rapamycin (mTOR) inhibitors, which are a standard treatment for advanced clear cell renal cell carcinoma (ccRCC), eventually develops in most cases. In this study, we established a patient-derived xenograft (PDX) model which acquired resistance to the mTOR inhibitor temsirolimus, and explored the underlying mechanisms of resistance acquisition. Temsirolimus was administered to PDX model mice, and one cohort of PDX models acquired resistance after repeated passages. PDX tumors were genetically analyzed by whole-exome sequencing and detected several genetic alterations specific to resistant tumors. Among them, mutations in ANKRD12 and DNMT1 were already identified in the early passage of a resistant PDX model, and we focused on a DNMT1 mutation as a potential candidate for developing the resistant phenotype. While DNMT1 expression in temsirolimus-resistant tumors was comparable with the control tumors, DNMT enzyme activity was decreased in resistant tumors compared with controls. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9-mediated heterozygous knockdown of DNMT1 in the temsirolimus-sensitive ccRCC (786-O) cell line was shown to result in a temsirolimus-resistant phenotype in vitro and in vivo. Integrated gene profiles using methylation and microarray analyses of PDX tumors suggested a global shift for the hypomethylation status including promotor regions, and showed the upregulation of several molecules that regulate the mTOR pathway in temsirolimus-resistant tumors. Present study showed the feasibility of PDX model to explore the mechanisms of mTOR resistance acquisition and suggested that genetic alterations, including that of DNMT1, which alter the methylation status in cancer cells, are one of the potential mechanisms of developing resistance to temsirolimus.

SUBMITTER: Sakamoto H

PROVIDER: S-EPMC7826464 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Functional and genomic characterization of patient-derived xenograft model to study the adaptation to mTORC1 inhibitor in clear cell renal cell carcinoma.

Sakamoto Hiromasa H Yamasaki Toshinari T Sumiyoshi Takayuki T Takeda Masashi M Shibasaki Noboru N Utsunomiya Noriaki N Arakaki Ryuichiro R Akamatsu Shusuke S Kobayashi Takashi T Inoue Takahiro T Kamba Tomomi T Nakamura Eijiro E Ogawa Osamu O

Cancer medicine 20201027 1

Resistance to the mechanistic target of rapamycin (mTOR) inhibitors, which are a standard treatment for advanced clear cell renal cell carcinoma (ccRCC), eventually develops in most cases. In this study, we established a patient-derived xenograft (PDX) model which acquired resistance to the mTOR inhibitor temsirolimus, and explored the underlying mechanisms of resistance acquisition. Temsirolimus was administered to PDX model mice, and one cohort of PDX models acquired resistance after repeated ...[more]

PMID: 33107222

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Project description:Patient-derived xenografts (PDX) are high-fidelity cancer models typically credentialled by genomics, transcriptomics and proteomics. Characterization of metabolic reprogramming, a hallmark of cancer, is less frequent. Dysregulated metabolism is a key feature of clear cell renal cell carcinoma (ccRCC) and authentic preclinical models are needed to evaluate novel imaging and therapeutic approaches targeting metabolism. We characterized 5 PDX from high-grade or metastatic ccRCC by multiparametric magnetic resonance imaging (MRI) and steady state metabolic profiling and flux analysis. Similar to MRI of clinical ccRCC, T2-weighted images of orthotopic tumors of most PDX were homogeneous. The increased hyperintense (cystic) areas observed in one PDX mimicked the cystic phenotype typical of some RCC. The negligible hypointense (necrotic) areas of PDX grown under the highly vascularized renal capsule are beneficial for preclinical studies. Mean apparent diffusion coefficient (ADC) values were equivalent to those of ccRCC in human patients. Hyperpolarized (HP) [1-13C]pyruvate MRI of PDX showed high glycolytic activity typical of high-grade primary and metastatic ccRCC with considerable intra- and inter-tumoral variability, as has been observed in clinical HP MRI of ccRCC. Comparison of steady state metabolite concentrations and metabolic flux in [U-13C]glucose-labeled tumors highlighted the distinctive phenotypes of two PDX with elevated levels of numerous metabolites and increased fractional enrichment of lactate and/or glutamate, capturing the metabolic heterogeneity of glycolysis and the TCA cycle in clinical ccRCC. Culturing PDX cells and reimplanting to generate xenografts (XEN), or passaging PDX in vivo, altered some imaging and metabolic characteristics while transcription remained like that of the original PDX. These findings show that PDX are realistic models of ccRCC for imaging and metabolic studies but that the plasticity of metabolism must be considered when manipulating PDX for preclinical studies.

Dataset Information

Functional and genomic characterization of patient-derived xenograft model to study the adaptation to mTORC1 inhibitor in clear cell renal cell carcinoma.

Publications

Functional and genomic characterization of patient-derived xenograft model to study the adaptation to mTORC1 inhibitor in clear cell renal cell carcinoma.

Similar Datasets

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