Terminal differentiation and loss of tumorigenicity of human cancers via pluripotency-based reprogramming

Abstract

Pluripotent cells can be derived from various types of somatic cells by nuclear reprogramming using defined transcription factors. It is however unclear whether human cancer cells can be similarly reprogrammed and subsequently terminally differentiated with abrogation of tumorigenicity. Here, using sarcomas we show that human derived complex karyotype solid tumors: (1) can be reprogrammed into a pluripotent-like state as defined by all in vitro criteria used to define pluripotent stem cells generated from somatic cells; (2) can be terminally differentiated into mature connective tissue and red blood cells; and (3) terminal differentiation is accompanied with loss of both proliferation and tumorigenicity. We go on to perform the first global DNA promoter methylation and gene expression analyses comparing human cancers to their reprogrammed counterparts and report that reprogramming/differentiation results in significant epigenetic remodeling of oncogenes and tumor suppressors; while not significantly altering the differentiation status of the reprogrammed cancer cells, in essence de-differentiating them to a state slightly before the mesenchymal stem cell differentiation stage. Our data demonstrates that direct nuclear reprogramming can restore terminal differentiation potential to human derived cancer cells, with simultaneous loss of tumorigenicity, without the need to revert to an embryonic state. We anticipate that our models would serve as a starting point to more fully assess how nuclear reprogramming overcomes the multitude of genetic and epigenetic aberrancies inherent in human cancers to restore normal terminal differentiation pathways. Finally, these findings suggest that nuclear reprogramming may be a broadly applicable therapeutic strategy for the treatment of cancer.

Emerging Roles of Krüppel-Like Factor 4 in Cancer and Cancer Stem Cells

“…Recent progress has demonstrated that P53 mutations can enhance the efficiency of reprogramming, and upregulation of KLF4 in mutant somatic cells, or P53-knockout cells, produces aggressive cancers in mice (Sarig et al, 2010). Reprogramming of cancer cells by pluripotency factors has been proposed as potential cancer therapies due to their capability to restore terminal differentiation of cancer cells in vitro, increase the responsiveness of cancer cells to chemotherapy in vitro, and reduce the tumorigenicity in vivo (Zhang et al, 2013).…”

Xenopatients 2.0: Reprogramming the epigenetic landscapes of patient-derived cancer genomes

“…These findings support the notion that the epigenetic modification of a cancer cell via nuclear reprogramming could correct some malignant effects of oncogene activation and oncosuppressor gene inactivation, which may constitute the basis for a novel strategy to control tumor progression. 81,82 Zhang et al 81 reported the terminal differentiation and loss of tumorigenicity of human sarcomas via pluripotency-based reprogramming, but these authors failed to observe benign mature tissue elements in their teratomas assays. Kim et al, 83 the only group that has reported the successful generation of a patient-derived iPS cell line from human pancreatic ductal adenocarcinoma (PDAC), only obtained one iPS-like line from a pancreatic cancer harboring a KRAS mutation, the predominant driver of PDAC, and a deletion in exon 2 of the pivotal tumor suppressor CDKN2A.…”

“…However, these authors reported only xenograft formation with no histology or immunohistochemistry. Zhang et al 81 recently demonstrated that the reprogramming of sarcoma cells using the 4 canonical Yamanaka genes plus Nanog and Lin28 created cancer cells that lost their tumorigenicity, exhibited reduced drug resistance, and dedifferentiated as iPS cells into various lineages, such as fibroblasts and hematopoietic lineages. Interestingly, the expression of endogenous c-Myc appeared to be reduced in their cellular model, and it was hypermethylated during the reprogramming process.…”

Back on Track: New Perspectives on Cancer Cell Reprogramming

“…This paper presents an alternative approach to cancer cell reprogramming towards a differentiated state, by skipping the iPSCs production passage usually found in the literature [9]. We supposed that cancer cells already showed sufficient stem-cell-like behavior to be ready for direct differentiation towards other germ layer lineages.…”

“…This metabolic switch is evidenced by a modulation in the expression of glycolysis enzymes, with a lowered expression of the glycolytic enzyme isoforms involved in the Warburg effect such as HK2, IDH2 and PKM2 [7] Concomitantly, we observe an increase in oxidative phosphorylation, as deduced by the decreased ATP content in differentiated cells compared to SH-SY5Y cells, following the in vitro inhibition of the mitochondrial electron transport chain. Restoration of mitochondrial activity is accompanied by a marked increase in Sirt3 activity [8].This paper presents an alternative approach to cancer cell reprogramming towards a differentiated state, by skipping the iPSCs production passage usually found in the literature [9]. We supposed that cancer cells already showed sufficient stem-cell-like behavior to be ready for direct differentiation towards other germ layer lineages.…”