The X-linked transcription factor FOXP3 is expressed by epithelial cells of organs including the breast, where it is considered a tumour suppressor. The chemokine receptor CXCR4 also regulates the development of breast cancer by stimulating cell migration towards CXCL12-expressing sites of metastatic spread. During activation, human T cells show reciprocal regulation of FOXP3 and CXCR4. This study was designed to examine the role FOXP3 plays in metastatic breast cancer, with a particular focus on its potential to regulate CXCR4. Human breast cancer samples showed significantly decreased FOXP3 protein expression but an increased number of CXCR4 transcripts. In comparison with normal primary breast epithelial cells, FOXP3 was down-regulated at both transcript and protein levels in the breast cancer cell lines MCF-7 and MDA-MB-231. In the invasive MDA-MB-231 cells, the remaining FOXP3 was located predominately within the cytoplasm. Following stable FOXP3 overexpression in MDA-MB-231 cells, significant decreases were observed in the expression of ErbB2/HER2, SKP2, c-MYC, and CXCR4. In contrast, an increase in p21 expression led to inhibition of cell proliferation, with a greater proportion in the G1 phase of the cell cycle suggesting the induction of senescence. Specific knockdown of FOXP3 in normal human breast epithelial cells with siRNA significantly increased ErbB2/HER2, SKP2, c-MYC, and CXCR4, and decreased p21 expression. These cells also showed a significantly increased chemotactic response towards CXCL12, consistent with a role for FOXP3 in the regulation of cell migration. Results from this study are consistent with FOXP3 functioning as an important tumour suppressor in breast cancer. Indeed, the potential functions of FOXP3 in breast epithelium can now be extended to include regulation of CXCR4 expression and response to the pro-metastatic chemokine CXCL12.
The FOXP3 transcription factor can regulate T cell migration by inhibiting expression of CXCR4, the receptor for the chemokine CXCL12. The increased expression of CXCR4 by breast cancer cells can drive metastatic migration towards sites that express CXCL12. Intracellular trafficking of FOXP3 to the nucleus is
The undergraduate curriculum is the starting point for the doctors of the future. It should provide a strong foundation for learning and practice as a junior doctor and beyond. In the modern era, anatomy teaching, as with all other areas of the curriculum, has needed to be tailored to fulfill this outcome effectively. Traditionally, anatomy has been taught by a method based on dissection of the human body. Dissection of the human body during an anatomy course raises questions about invasion of privacy, issues of introducing dying and death appropriately to medical students as well as issues of cost and practicality. These issues have been the subjects of much debate.
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