Involvement of CD24 in Multiple Cancer Related Pathways Makes It an Interesting New Target for Cancer Therapy

CD24 (cluster of differentiation 24) is a small heavy glycosylated protein, which is overexpressed in many cancer and some cancer stem cells and is associated with the development, invasion, and metastasis of cancer cells. The exact role of CD24 in these processes is not fully understood, however, in this article, it has been tried to present a collection of cancer-related mechanisms attributed to CD24. Based on the literature, CD24 dis-regulates different signaling pathways in various cancer cells, including; Src kinases, STAT3, EGFR, Wnt/β-catenin and MAPK. Src kinases play an important role in the signaling pathways which activate p38 MAPK and STAT3 pathways. Akt and ERK are downstream effectors of CD24-activated EGFR, which promote cell proliferation, invasion and metastasis. CD24 increases the expression of HER2 by the activation of NF-κB transcription factor. Moreover, CD24 up-regulates the expression of miR-21 oncomir through the activation of Src kinases. Identification of the details of these pathways and also new pathways will help researchers to explore new CD24 targeted therapies.

Establishment and characterization of cloned CD4- CD8- alphabeta-T cell receptor (TCR)-bearing autoreactive T cells from autoimmune NZB x NZW F1 mice

Murine models such as NZB/W F1, NZB.H-2bm12 and MRL.lpr/lpr mice have provided greater insight into the pathogenic mechanisms of lupus. To understand further the roles of T cells and cytokines in the pathogenesis of murine lupus, 11 cloned anti-DNA antibodies augmenting autoreactive T cell lines were derived from NZB/W F1 mice. All these autoreactive cells responded to syngeneic splenic cells and helped syngeneic B cells to produce anti-DNA antibodies, especially the IgG antibody. Ten out of 11 autoreactive T cell lines expressed neither CD4 nor CD8 cell surface markers on their surface. In addition, the cytokine production pattern of these autoreactive T cell lines was predominantly of type 0 (Th0) or type 2 T helper cells (Th2). To further investigate the role of accessory molecules in the activation of these autoreactive T cell lines, expression of IL-2R and heat-stable antigen (HSA) on these autoreactive T cells was analysed. Results suggest that the HSA played a critical role in the activation and function of these double-negative cloned autoreactive T cells.

The gamma delta T lymphocytes of the perinatal murine thymus

We have previously shown that the adult thymus contains three subsets of gamma delta T cells that can be defined by the expression of THY-1 and heat-stable antigen (HSA). In this study, the number of cells in each of these thymic gamma delta populations was investigated at different stages throughout life. In adult mice, the populations stay relatively constant, however, in contrast, there were major variations in them early in development. It was shown that only two of the gamma delta populations were present in the prenatal thymus, a major population of Thy-1+ HSA - cells, and a smaller population of Thy-1+ HSA+ cells. However, after birth, most of the Thy-1+ HSA - cells appear to loose the Thy-1 antigen, forming the third population of HSA - Thy-1 - cells. The adult configuration of populations appeared to be established within the first week after birth. Therefore, whereas the gamma delta populations stayed relatively constant from this time point onwards, there were major variations early in development. Throughout life, most gamma delta thymocytes are CD4- CD8-, however, in the neonatal thymus, there are some CD+ and CD+ gamma delta thymocytes, and these are contained in the Thy-1+ HSA - population.