CD34—Structure, Functions and Relationship with Cancer Stem Cells

Abstract

The CD34 protein was identified almost four decades ago as a biomarker for hematopoietic stem cell progenitors. CD34 expression of these stem cells has been exploited for therapeutic purposes in various hematological disorders. In the last few decades, studies have revealed the presence of CD34 expression on other types of cells with non-hematopoietic origins, such as interstitial cells, endothelial cells, fibrocytes, and muscle satellite cells. Furthermore, CD34 expression may also be found on a variety of cancer stem cells. Nowadays, the molecular functions of this protein have been involved in a variety of cellular functions, such as enhancing proliferation and blocking cell differentiation, enhanced lymphocyte adhesion, and cell morphogenesis. Although a complete understanding of this transmembrane protein, including its developmental origins, its stem cell connections, and other functions, is yet to be achieved. In this paper, we aimed to carry out a systematic analysis of the structure, functions, and relationship with cancer stem cells of CD34 based on the literature overview.

FLT3 and IRAK4 Inhibitor Emavusertib in Combination with BH3-Mimetics in the Treatment of Acute Myeloid Leukemia

“…The surface marker CD34 was negatively associated with the response to CA4948, S63845, and PU-H71 treatment, with elevated susceptibility of primary AML samples with CD34 <30%. CD34 is a hematopoietic stem cell marker and may mediate the attachment to the bone marrow extracellular matrix and stromal cells [44]. Leukemic stem cells are a subpopulation of leukemia cells characterized by the CD34 + CD38-phenotype, and are considered to be resistant to standard treatment [45].…”

New Insights in ATP Synthesis as Therapeutic Target in Cancer and Angiogenic Ocular Diseases

“…28,29 CD34 is a member of the CD34 transmembrane phosphoglycoproteins family together with endoglycan and podocalyxin. 110,111 CD34 is expressed on stem cells and progenitor cells as well as CSCs and enhances cell proliferation and inhibits cell differentiation. CD34 stimulates cell migration and can promote and block cell adhesion.…”

“…73 The exact roles of CD34 in (cancer) stem cells, progenitor cells, and ECs are still far from understood. 111 In the next section of this review, we evaluate energy metabolism in tip ECs and non-tip ECs (proliferating stalk ECs, maturing phalanx ECs, and quiescent mature ECs), as well as that of PCs as a potential target for anti-angiogenic therapy in ocular diseases.…”

“…CD34 stimulates cell migration and can promote and block cell adhesion. 110 , 111 CD34 is a biomarker of EC precursor cells and of tip ECs in vitro , whereas in vivo it is expressed on the apical membrane of ECs during angiogenesis and plays an anti-adhesive role in lumen formation and possibly in maintaining lumina of capillaries ( Fig. 6 ).…”

“… 73 The exact roles of CD34 in (cancer) stem cells, progenitor cells, and ECs are still far from understood. 111 …”