Cells, Stem Cells, and Cancer Stem Cells

Abstract

The stem cell field owes a great deal to the previous work conducted by embryologists and researchers devoted to reproductive medicine. The time is coming when this emerging field will pay off in the reproductive sciences by offering new avenues of understanding gametogenesis and early embryonic development. Human embryonic stem cells are pluripotent cells that proliferate in vitro while maintaining an undifferentiated state, and they are capable of differentiating into most cell types under appropriate conditions. Embryo-friendly approaches have been developed as new methods of obtaining human embryonic stem cells without destroying the embryo. Somatic stem cells have been identified and isolated from numerous adult organs and tissues to create a multipotent and autologous source of cells with established medical indications. Cell reprogramming is now a scientific fact, and induced pluripotent cells, a new pluripotent cell type, have been generated by the overexpression of specific genes from a myriad of differentiated adult cell types. Cancer is now considered a stem cell disease. Cancer stem cells share numerous features with normal stem cells including hallmarks properties such as self-renewal and undifferentiation. Therefore, the actual focus of ovarian cancer research on the cancer stem cell model should generate efficient and personalized treatment designs to improve treatment efficiency.

Peritoneal carcinomatosis: A malignant disease with an embryological origin?

“…Recent studies criticize carcinogenesis models based on the accumulation of genetic mutations of normal somatic cells because of their simplicity [14,15] and propose an alternative theory based on genetic and epigenetic events that occur in stem cells (SCs). SCs play a role both in transcoelomic spread and in the development of the peritoneum in the embryo.…”

Immunohistochemical Detection of Cancer Stem Cell Related Markers CD44 and CD133 in Metastatic Colorectal Cancer Patients

“…Both of these cell types are undifferentiated with the capacity to differentiate into hierarchical sequence of other tumor or normal cells; they are capable of self-renewal and asymmetric division and they have relatively long cycling times and long-term survival [8]. In addition to this, CSCs were described to be highly resistant to chemotherapy and radiotherapy which makes them very difficult to target and eliminates them by common therapy regimens.…”

Metabolic regulation of glioma stem-like cells in the tumor micro-environment

“…These differentiation events are functionally important and tend to result in committed cellular steps towards terminal cell states. However, it is an important aspect of tissue homeostasis to maintain certain sub-populations of stem-like precursors that can give rise to functionally mature progeny in the event of cellular turnover or wound healing [13]. In cancer, it has been proposed that elements of this homeostatic mechanism have been hijacked for cancer propagation.…”

“…In light of current understandings of tumor heterogeneity and tumor resistance/recurrence, it is more likely that both of these models may in fact describe different elements of a central process and therefore both explain the cancer stem cell model to a point, as some have proposed a hybrid of the two theories to explain the complex dynamics involved (Fig. 1) [13,16,17,18]. The important fact remains that however these cells may have come to be, the elimination of the cancer stem cell population in any tumor model represents one of the most important hurdles to cancer research and treatment today.…”

“…Normal tumor cells may not be able to modulate their metabolism as readily or utilize microenvironmental alterations to glucose or oxygen accessibility to such effect. Additionally, microenvironmental inflammation and subsequent secretion of cytokines such as IL-6 and IL-8 along with NFκB activation has been shown to drive PI3K/Akt mediated glycolytic shifts in CSCs and promote CSC self-renewal [79,80,81]. More work in this area needs to be done but the idea that cytokine modulation in the microenvironment could again promote stemness and metabolic plasticity of CSCs lends more credence to the idea that the microenvironment-CSC crosstalk is a vital component of metabolism and resistance in many tumors.…”