Molecular Profiling of Conjunctival Epithelial Side-Population Stem Cells: Atypical Cell Surface Markers and Sources of a Slow-Cycling Phenotype

Hematopoietic stem cells (HSCs) are a self-renewing population of bone marrow cells that replenish the cellular elements of blood throughout life. HSCs represent a paradigm for the study of stem-cell biology, because robust methods for prospective isolation of HSCs have facilitated rigorous characterization of these cells. Recently, a new isolation method was reported, using the SLAM family of cell-surface markers, including CD150 (SlamF1), to offer potential advantages over established protocols. We examined the overlap between SLAM family member expression with an established isolation scheme based on Hoechst dye efflux (side population; SP) in conjunction with canonical HSC cell-surface markers (Sca-1, c-Kit, and lineage markers). Importantly, we find that stringent gating of SLAM markers is essential to achieving purity in HSC isolation and that the inclusion of canonical HSC markers in the SLAM scheme can greatly augment HSC purity. Furthermore, we observe that both CD150+ and CD150− cells can be found within the SP population and that both populations can contribute to long-term multilineage reconstitution. Thus, using SLAM family markers to isolate HSCs excludes a substantial fraction of the marrow HSC compartment. Interestingly, these 2 subpopulations are functionally distinct, with respect to lineage output as well as proliferative status.

Download Full-text

Side Population Cells as Prototype of Chemoresistant, Tumor-Initiating Cells

BioMed Research International ◽

10.1155/2013/517237 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 42

Author(s):

Vinitha Richard ◽

Madhumathy G. Nair ◽

T. R. Santhosh Kumar ◽

M. Radhakrishna Pillai

Keyword(s):

Stem Cells ◽

Cancer Stem Cells ◽

Cell Surface ◽

Regulatory Networks ◽

Side Population ◽

Surface Markers ◽

Cell Surface Markers ◽

Tumor Initiating Cells ◽

Alternative Source ◽

Almost All

Classically, isolation of CSCs from tumors exploits the detection of cell surface markers associated with normal stem cells. Invariable expression of these cell surface markers in almost all proliferating tumor cells that albeit impart specific functionality, the universality, and clinical credibility of CSC phenotype based on markers is still dubious. Side Population (SP) cells, as defined by Hoechst dye exclusion in flow cytometry, have been identified in many solid tumors and cell lines and the SP phenotype can be considered as an enriched source of stem cells as well as an alternative source for the isolation of cancer stem cells especially when molecular markers for stem cells are unknown. SP cells may be responsible for the maintenance and propagation of tumors and the proportion of SP cells may be a predictor of patient outcome. Several of these markers used in cell sorting have emerged as prognostic markers of disease progression though it is seen that the development of new CSC-targeted strategies is often hindered by poor understanding of their regulatory networks and functions. This review intends to appraise the experimental progress towards enhanced isolation and drug screening based on property of acquired chemoresistance of cancer stem cells.

Download Full-text

Neonatal stem cells exhibit specific characteristics in function, proliferation, and cellular signaling that distinguish them from their adult counterparts

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00031.2008 ◽

2008 ◽

Vol 294 (5) ◽

pp. R1491-R1497 ◽

Cited By ~ 14

Author(s):

Troy A. Markel ◽

Meijing Wang ◽

Paul R. Crisostomo ◽

Maiuxi C. Manukyan ◽

Jeffrey A. Poynter ◽

...

Keyword(s):

Stem Cells ◽

Cell Surface ◽

Surface Markers ◽

Cell Surface Markers ◽

Local Inflammatory Response ◽

Cell Counts ◽

Marrow Mesenchymal Stem Cells ◽

Growth Factor Production ◽

Erk Inhibition ◽

Different Levels

Stem cells may be a novel treatment modality for organ ischemia, possibly through beneficial paracrine mechanisms. Stem cells from older hosts have been shown to exhibit decreased function during stress. We therefore hypothesized that 1) neonatal bone marrow mesenchymal stem cells (nBMSCs) would produce different levels of IL-6, VEGF, and IGF-1 compared with adults (aBMSCs) when stimulated with TNF or LPS; 2) differences in cytokines would be due to distinct cellular characteristics, such as proliferation or pluripotent potential; and 3) differences in cytokines would be associated with differences in p38 MAPK and ERK signaling within nBMSCs. BMSCs were isolated from adult and neonatal mice. Cells were exposed to TNF or LPS with or without p38 or ERK inhibition. Growth factors were measured via ELISA, proliferation via daily cell counts, cell surface markers via flow cytometry, and pluripotent potential via alkaline phosphatase activity. nBMSCs produced lower levels of IL-6 and VEGF, but higher levels of IGF-1 under basal conditions, as well as after stimulation with TNF, but not LPS. Neonatal and adult BMSCs had similar pluripotent potentials and cell surface markers, but nBMSCs proliferated faster. Furthermore, p38 and ERK appeared to play a more substantial role in nBMSC cytokine and growth factor production. Neonatal stem cells may aid in decreasing the local inflammatory response during ischemia, and could possibly be expanded more rapidly than adult cells prior to therapeutic use.

Download Full-text