Heterogeneity of Functional Properties of Clone 66 Murine Breast Cancer Cells Expressing Various Stem Cell Phenotypes

Abstract

IntroductionBreast cancer grows, metastasizes and relapses from rare, therapy resistant cells with a stem cell phenotype (cancer stem cells/CSCs). However, there is a lack of studies comparing the functions of CSCs isolated using different phenotypes in order to determine if CSCs are homogeneous or heterogeneous.MethodsCells with various stem cell phenotypes were isolated by sorting from Clone 66 murine breast cancer cells that grow orthotopically in immune intact syngeneic mice. These populations were compared by in vitro functional assays for proliferation, growth, sphere and colony formation; and in vivo limiting dilution analysis of tumorigenesis.ResultsThe proportion of cells expressing CD44highCD24low/neg, side population (SP) cells, ALDH1+, CD49fhigh, CD133high, and CD34high differed, suggesting heterogeneity. Differences in frequency and size of tumor spheres from these populations were observed. Higher rates of proliferation of non-SP, ALDH1+, CD34low, and CD49fhigh suggested properties of transit amplifying cells. Colony formation was higher from ALDH1− and non-SP cells than ALDH1+ and SP cells suggesting a progenitor phenotype. The frequency of clonal colonies that grew in agar varied and was differentially altered by the presence of Matrigel™. In vivo, fewer cells with a stem cell phenotype were needed for tumor formation than “non-stem” cells. Fewer SP cells were needed to form tumors than ALDH1+ cells suggesting further heterogeneities of cells with stem phenotypes. Different levels of cytokines/chemokines were produced by Clone 66 with RANTES being the highest. Whether the heterogeneity reflects soluble factor production remains to be determined.ConclusionsThese data demonstrate that Clone 66 murine breast cancer cells that express stem cell phenotypes are heterogeneous and exhibit different functional properties, and this may also be the case for human breast cancer stem cells.

Expression of CD 133 in Invasive Ductal Carcinoma of Breast

“…CD133, also known as prominin-1, is a trans-membrane glycoprotein expressed in various malignancies, such as breast carcinomas, brain tumors, pancreatic cancer, non-small cell lung cancer, hepatocellular carcinoma, and ovarian cancer. In breast carcinomas, the expression of CD133 and its relation with histopathological parameters has yielded conflicting results which may be attributed to different research methodologies and differences between study populations (Mukhopadhyay et al, 2013;Zhan et al, 2017;Kim et al, 2015;Margaret et al, 2013). In this regard few studies have been done to look into the role of CD133 in breast carcinoma.…”

The role of autophagy in the cross-talk between epithelial-mesenchymal transitioned tumor cells and cancer stem-like cells

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“…Of particular relevance in the present context is the observation that CSCs can be distinguished in predominantly non-cycling CSCs and cycling CSCs [ 54 , 58 – 60 ]. This is reminiscent of the proliferating and dormant subpopulations of somatic stem cells, with the dormant stem cell pool representing the most primitive stem cells [ 55 ].…”

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