Demonstration of CD44 gene expression in cells from fine needle aspirates of breast lesions by the polymerase chain reaction

Uncoupling of the ERα regulated morphological phenotype from the cancer stem cell phenotype in human breast cancer cell lines

The CD24(low/-)CD44(+)EpCAM(+) phenotype is associated with breast cancer initiating cells. To investigate if these putative breast cancer stem cell markers are regulated by estrogen receptor alpha (ERα) we have determined the expression levels of EpCAM, CD44 and CD24 in several well characterized breast cancer cell lines. The expression levels of the three adhesion proteins were quantitatively different in the cell lines but the composite CD24(low/-)CD44(+)EpCAM(+) breast cancer stem cell phenotype was shown to exist as a small fraction, between 0.1% and 1.2%, in all breast cancer cell lines tested. Experimental silencing of ERα resulted in a reduced epithelial appearance and partial reduction of CD24 mRNA, while levels of CD44 and EpCAM were unaltered. Moreover, knockdown of ERα led to a change in the morphology of the cells similar to the epithelial to mesenchymal transition phenotype and was associated with decreased E-cadherin expression. Our findings offer new insights into the regulation of the breast cancer stem cell phenotype by ERα and suggest that treatments targeting the breast cancer stem cell adhesion molecules and the ERα pathway may be complementary.

Distribution of CD44 messenger RNA in archival paraffin wax embedded tumours and normal tissues viewed by in situ hybridisation

Aims-We have previously demonstrated the abnormal localisation of expression of the CD44 gene in carcinoma cells in cryostat sections of fresh frozen tumour tissues, using radioactive in situ hybridisation (RISH). In order to facilitate further analysis of the expression of this gene in a wider range of neoplastic and non-neoplastic conditions, we have developed a technique which can visualise its low copy number transcripts in archival paraffin wax embedded specimens.Methods-(35)S labelled riboprobes complementary to transcripts from the standard (CD44s) and variant (CD44v) regions of the gene were used on paraffin wax embedded sections of tumours and corresponding normal tissues of the colon, breast and uterine cervix.Results-Elevated levels of signals for CD44s and CD44v transcripts were observed in carcinoma cells relative to their non-neoplastic counterparts in all tissues examined.Conclusion-This method permits easy access to material which can be selected for suitability, handled at room temperature without degradation and relied upon to show good histological detail. Comparison of the results with those on frozen tissues showed similar distributions of signals. Furthermore, the resolution and morphological detail was improved in paraffin wax sections.