Characterization of brain tumor initiating cells isolated from an animal model of CNS primitive neuroectodermal tumors

Abstract

CNS Primitive Neuroectodermal tumors (CNS-PNETs) are members of the embryonal family of malignant childhood brain tumors, which remain refractory to current therapeutic treatments. Current paradigm of brain tumorigenesis implicates brain tumor-initiating cells (BTIC) in the onset of tumorigenesis and tumor maintenance. However, despite their significance, there is currently no comprehensive characterization of CNS-PNETs BTICs. Recently, we described an animal model of CNS-PNET generated by orthotopic transplantation of human Radial Glial (RG) cells - the progenitor cells for adult neural stem cells (NSC) - into NOD-SCID mice brain and proposed that BTICs may play a role in the maintenance of these tumors. Here we report the characterization of BTIC lines derived from this CNS-PNET animal model. BTIC’s orthotopic transplantation generated highly aggressive tumors also characterized as CNS-PNETs. The BTICs have the hallmarks of NSCs as they demonstrate self-renewing capacity and have the ability to differentiate into astrocytes and early migrating neurons. Moreover, the cells demonstrate aberrant accumulation of wild type tumor-suppressor protein p53, indicating its functional inactivation, highly up-regulated levels of onco-protein cMYC and the BTIC marker OCT3/4, along with metabolic switch to glycolysis - suggesting that these changes occurred in the early stages of tumorigenesis. Furthermore, based on RNA- and DNA-seq data, the BTICs did not acquire any transcriptome-changing genomic alterations indicating that the onset of tumorigenesis may be epigenetically driven. The study of these BTIC self-renewing cells in our model may enable uncovering the molecular alterations that are responsible for the onset and maintenance of the malignant PNET phenotype.

Metabolism-Based Therapeutic Strategies Targeting Cancer Stem Cells

“…Importantly, such inverse relationship was functionally proven in embryonal carcinoma cells derived from teratocarcinomas, since the stimulation of mitochondrial function induced cell differentiation and loss of pluripotency (Vega-Naredo et al, 2014). In fact, the occurrence of this metabolic switch, not the final glycolytic phenotype, seems to be key for early state of tumorigenesis and acquisition of stemness-related properties in human mammospheres and brain CSCs in a mouse model of primitive neuroectodermal tumors (Dong et al, 2013; Ciavardelli et al, 2014; Malchenko et al, 2018).…”

Inorganic polyphosphate as an energy source in tumorigenesis

“…We also described an animal model of malignant childhood brain tumors that can be generated by orthotopic transplantation of RG cells into the sub-ventricular zone of the mouse brain [ 28 ]. Consequently, we derived and characterized brain cancer stem cells (CSCs), also known as BTICs, from these model tumors (see below: LC26-RTL(4) and LCAS-7RTL(138) cell lines) [ 29 ].…”

“…Previously described Radial Glial cell line LC26-10R and BTIC line LC26-RTL(4) (generated from LC26-10R) [ 29 ] were maintained in the exponential growth phase by passaging them every 3 days with growth medium Knockout DMEM/F-12 (Gibco, 12-660012) supplemented with 2% Stempro Neural Suppliment (Gibco, A1050801), 1% Hyclone Antibiotic/Antimycotic (GEHealthcare Life Sciences, SV30079.01SV3007901), 1% Glutamax (Gibco, 35-050-061) and 10 ng/mL bFGF (Sigma, GF003-AF) in laminin (Invitrogen, 23017015) coated 35 mm culture dish in CO 2 incubator at 37°C.…”

Machine Learning Approach-Based Gamma Distribution for Brain Tumor Detection and Data Sample Imbalance Analysis

“…This edge-based image segmentation [17] coordinate matching with automatic ROI detection was implemented using an orthogonal gamma distribution model with a machine learning approach. Because this algorithm self-identifies the region of interest (ROI) [18] it is distinctive among other techniques, such as Li's method, Chehade's method, and Otsu's method. Figure 2 shows the image of a brain tumor.…”