A strategy to eradicate well-developed Krebs-2 ascites in mice

Abstract

We describe the strategy, which allows curing experimental mice engrafted with Krebs-2 ascites. The strategy is based on the facts that i) Krebs-2 tumor-initiating stem cells (TISCs) are naturally capable of internalizing fragments of extracellular double-stranded DNA (dsDNA); ii) upon delivery into TISCs, these dsDNA fragments interfere with the on-going DNA repair process so that TISCs either die or lose their tumorigenic potential. The following 3-step regimen of therapeutic procedures leading to eradication of Krebs-2 ascites is considered. Firstly, three timed injections of cyclophosphamide (CP) exactly matching the interstrand cross-link (ICL) repair phases that lead to synchronization of ascites cells in late S/G2/M. Secondly, additional treatment of ascites 18 hours post each CP injection (at NER/HR transition timepoint) with a composite dsDNA-based preparation interfering with the NER and HR repair pathways, so that tumorigenic properties of ascites cells are compromised. Thirdly, final treatment of mice with a combination of CP and dsDNA injections as ascites cells undergo apoptotic destruction, and the surviving TAMRA+ TISCs arrested in late S/G2/M phases massively enter into G1/S, when they regain sensitivity to CP+dsDNA treatment. Thus, this regimen assures that no viable cells, particularly Krebs-2 TISCs, remain.

Identification of the xenograft and its ascendant sphere-forming cell line as belonging to EBV-induced lymphoma, and characterization of the status of sphere-forming cells

“…These cells could be related to the subpopulation of TAMRA+ cells present in a small proportions (less than 1%) in the mouse and human bone marrow [11]. However, as follows from our previous reports, the ability to capture extracellular double-stranded DNA fragments is the hallmark of only undifferentiated cells, both normal and cancerous [7][8][9][10][11][12][13][14].…”

“…Primary free-floating spheres were shown to contain cells with the characteristic B cell surface marker CD20. The spheres contained 1-3% of cells with inherent capability of internalizing a TAMRAlabeled double-stranded DNA probe [7][8][9][10][11][12][13][14]. These undifferentiated cells, together with a group of floating TAMRA-negative cells, constituted a sphere-organizing center, inducing repeated aggregation of cells into a spherical 3d structure.…”

Gene expression profiling of tumor-initiating stem cells from mouse Krebs-2 carcinoma using a novel marker of poorly differentiated cells

“…Elimination of these cells results in elimination of the engraftment potential of the cells and in curing of the mice from developed Krebs-2 ascites [16, 20]. …”

Evaluation of a strategy for tumor-initiating stem cell eradication in primary human glioblastoma cultures as a model

“…Необходимым условием применения разработанной стратегии является использование сложнокомпозиционного препарата, составные части которого дифференцированно интерферируют стадию эксцизионной репарации нуклеотидов (NER -nucleotide excision repair) и стадию гомологичной рекомбинации в СИРК. Такой принцип полностью лишает возможности СИРК преодолеть терапевтическую обработку, что сопровождается их разрушением и вылечиванием животных от рака (Dolgova et al, 2014;Potter et al, 2016).…”

“…В клеточном сообществе асцитных раковых клеток существует две дискриминируемые по признаку интернализации TAMRAмеченной ДНК популяции клеток, которые захватывают ДНКзонд (TAMRA+ клетки) и не захватывают его (TAMRA-клетки). Известно, что TAMRA+ клетки обладают свойствами СИРК (Dolgova et al, 2014;Potter et al, 2016Potter et al, , 2017. Было сделано предположение, что эти две популяции клеток поразному завершают остановку клеточного цикла в поздней S/G2/Mфазе клеточного цикла.…”