Cancer Stem Cells: Emergent Nature of Tumor Emergency

A functional analysis of 167 genes overexpressed in Krebs-2 tumor initiating cells was performed. In the first part of the study, the genes were analyzed for their belonging to one or more of the three groups, which represent the three major phenotypic manifestation of malignancy of cancer cells, namely (1) proliferative self-sufficiency, (2) invasive growth and metastasis, and (3) multiple drug resistance. 96 genes out of 167 were identified as possible contributors to at least one of these fundamental properties. It was also found that substantial part of these genes are also known as genes responsible for formation and/or maintenance of the stemness of normal pluri-/multipotent stem cells. These results suggest that the malignancy is simply the ability to maintain the stem cell specific genes expression profile, and, as a consequence, the stemness itself regardless of the controlling effect of stem niches. In the second part of the study, three stress factors combined into the single concept of “generalized cellular stress,” which are assumed to activate the expression of these genes, were defined. In addition, possible mechanisms for such activation were identified. The data obtained suggest the existence of a mechanism for the de novo formation of a pluripotent/stem phenotype in the subpopulation of “committed” tumor cells

The Basis of Anticancer Immunity Mechanism Induced by In Situ Vaccination

В обзоре предпринята попытка охарактеризовать принципы возникновения и распространения системного противоопухолевого иммунного ответа при in situ вакцинации – новом направлении в экспериментальной иммунотерапии злокачественных новообразований. Современные методы иммунотерапии опухолей, как правило, требуют обязательного наличия специфического антигена-мишени. Подход с использованием in situ вакцинации не требует специфического антигена. Вся совокупность детерминант, необходимых для формирования иммунного ответа, появляется в сайте вакцинации в результате лизиса опухолевых клеток клетками врожденного иммунитета, инфильтрирующими опухоль и активированными в результате проведенных обработок. Первая часть обзора представляет собой систематизацию известных литературных данных в разрезе причин, обстоятельств и факторов, определяющих возможность появления в локальном опухолевом очаге всей совокупности опухолевых антигенов, необходимых для развития противоопухолевого адаптивного иммунитета. Вторая часть обзора базируется на проведенной систематизации и представляет собой анализ возможных событий развития системного противоопухолевого иммунного ответа при in situ вакцинации с использованием платформы рецептор-лиганд/антигенпрезентирующие клетки на примере синергичного действия CpG олигонуклеотидов и антител OX40The present review is an attempt to characterize the principles of both onset and development of the systemic antitumor immune response triggered by in situ vaccination, which is a new trend in anticancer immunotherapy. Modern methods of cancer immunotherapy usually require the presence of a specific target antigen. The in situ vaccination approach does not need a specific antigen. The determinants necessary for the formation of the immune response are all present at the vaccination site, as tumor cells are lysed by cells of innate immunity, infiltrating the tumor and activated by the treatments. The first part of the review is a compilation of the literature data on causes, circumstances, and factors determining the presence in the local tumor node of the totality of tumor antigens essential for the development of the adaptive antitumor immune response. The second part of the review analyzes possible events of antitumor immune response development due to in situ vaccination using ligand-receptor interaction and antigen-presenting cells activation, based on the data structuring performed previousl

The New General Biological Property of Stem-like Tumor Cells (Part II: Surface Molecules, Which Belongs to Distinctive Groups with Particular Functions, Form a Unique Pattern Characteristic of a Certain Type of Tumor Stem-like Cells)

An ability of poorly differentiated cells of different genesis, including tumor stem-like cells (TSCs), to internalize extracellular double-stranded DNA (dsDNA) fragments was revealed in our studies. Using the models of Krebs-2 murine ascites carcinoma and EBV-induced human B-cell lymphoma culture, we demonstrated that dsDNA internalization into the cell consists of several mechanistically distinct phases. The primary contact with cell membrane factors is determined by electrostatic interactions. Firm contacts with cell envelope proteins are then formed, followed by internalization into the cell of the complex formed between the factor and the dsDNA probe bound to it. The key binding sites were found to be the heparin-binding domains, which are constituents of various cell surface proteins of TSCs—either the C1q domain, the collagen-binding domain, or domains of positively charged amino acids. These results imply that the interaction between extracellular dsDNA fragments and the cell, as well as their internalization, took place with the involvement of glycocalyx components (proteoglycans/glycoproteins (PGs/GPs) and glycosylphosphatidylinositol-anchored proteins (GPI-APs)) and the system of scavenger receptors (SRs), which are characteristic of TSCs and form functional clusters of cell surface proteins in TSCs. The key provisions of the concept characterizing the principle of organization of the “group-specific” cell surface factors of TSCs of various geneses were formulated. These factors belong to three protein clusters: GPs/PGs, GIP-APs, and SRs. For TSCs of different tumors, these clusters were found to be represented by different members with homotypic functions corresponding to the general function of the cluster to which they belong

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

Abstract Background We have characterized the human cell line arised from the Epstein–Barr virus (EBV) positive multiple myeloma aspirate subjected to the long-term cultivation. This cell line has acquired the ability to form free-floating spheres and to produce a xenograft upon transplantation into NOD/SCID mice. Methods Cells from both in vitro culture and developed xenografts were investigated with a number of analytical approaches, including pathomorphological analysis, FISH analysis, and analysis of the surface antigens and of the VDJ locus rearrangement. Results The obtained results, as well as the confirmed presence of EBV, testify that both biological systems are derived from B-cells, which, in turn, is a progeny of the EBV-transformed B-cellular clone that supplanted the primordial multiple myeloma cells. Next we assessed whether cells that (i) were constantly present in vitro in the investigated cell line, (ii) were among the sphere-forming cells, and (iii) were capable of internalizing a fluorescent TAMRA-labeled DNA probe (TAMRA+ cells) belonged to one of the three types of undifferentiated bone marrow cells of a multiple myeloma patient: CD34+ hematopoietic stem cells, CD90+ mesenchymal stem cells, and clonotypic multiple myeloma cell. Conclusion TAMRA+ cells were shown to constitute the fourth independent subpopulation of undifferentiated bone marrow cells of the multiple myeloma patient. We have demonstrated the formation of ectopic contacts between TAMRA+ cells and cells of other types in culture, in particular with CD90+ mesenchymal stem cells, followed by the transfer of some TAMRA+ cell material into the contacted cell