Current methods for Cancer Stem Cell characterisation and isolation - Essay Example

Apart from achieving a 40-98% enrichment, this technique also produced spheres with enhanced tumorigenicity in immune-compromised mice [Ponti et.al. 2005]. Such a methodology has also been adopted for the enrichment of CSCs from brain [Singh et. al. 2003], bone sarcomas [Gibbs et.al. 2005], pancreas [Gou et. al. 2007], melanomas [Fang et. al. 2005] and colon [Ricci-Vitiani et. al. 2007]. The spheres produced in all these instances had a high level of surface markers that belong to the respective tumor initiators, namely CSCs.

The exploitation of the sphere forming properties of CSCs for their enrichment in culture is considerably more preferable than using surface markers or SPs. In spite of its utility, the process of isolation of CSCs based on sphere formation has significant limitations, the biggest one of which is that they are a heterogeneous population, wherein, only a few cells undergo self-renewal [Ponti et. al. 2005]. Furthermore, upon immunofluorescence analysis of spheres obtained in prostrate cell lines, it has been found that these are heterogenous for CSC surface markers [Patrawala et. al. 2006].

Moreover, variation in sphere size, culture medium and the differences in employed techniques for enrichment also limit the success of the process, as shown in neurosphere cultures [Jensen & Parmar 2006]. The ALDH enzyme plays an important role in the conversion of aldehydes into weak acids. This reaction is vital for the generation of biologically active substances. The ALDEFLUOR assay is based on an enzymatic reaction that measures aldhehyde dehydrogenase 1 (ALDH 1) activity. The detoxifying enzyme, ALDH 1, is responsible for the formation retinoic acid, a biologically active substance, from the oxidation of retinol.

The enzyme ALDH1 is abundant in primitive hematopoietic cells and is expressed in the early