Keywords: antitumor immunity, cancer stem cell, dendritic cell, metastasis, vaccine Abbreviations: ALDH, aldehyde dehydrogenase; CSC, cancer stem cell; CSC-DC, CSC lysate-pulsed dendritic cell; DC, dendritic cell; H-DC, heterogeneous, unsorted tumor cell lysate-pulsed dendritic cell; RT, radiation therapy; qRT-PCR, real time quantitative PCR.The inability to target cancer stem cells (CSC) may be a significant factor contributing to treatment failure. We have developed a strategy to target the CSC populations in melanoma and squamous cell carcinoma using CSC lysate-pulsed dendritic cells (DCs). The CSC-DC vaccine was administered in the adjuvant setting after localized radiation therapy of established tumors. Using mouse models we demonstrated that DCs pulsed with CSCs enriched by virtue of their expression of the CSC marker ALDH (termed CSC-DC) significantly inhibited tumor growth, reduced development of pulmonary metastases and prolonged survival. The effect was associated with downregulation of chemokine (C-C motif) receptors CCR7 and CCR10 in tumor cells and decreased expression of the chemokine (C-C motif) ligands CCL21, CCL27 and CCL28 in lung tissue. The CSC-DC vaccine significantly reduced ALDH high CSC frequency in primary tumors. Direct targeting of CSCs was demonstrated by the specific binding of IgG produced by ALDH high CSC-DC vaccineprimed B cells to ALDH high CSCs, resulting in lysis of these target CSCs in the presence of complement. These data suggest that the CSC-DC vaccine approach may be useful in the adjuvant setting where local and systemic relapse are high after conventional treatment of cancers.

Cancer stem cells promote tumorigenesis and progression of hepatocellular carcinoma (HCC). Recently, emerging evidence indicates tumor-associated macrophages (TAMs) play an important role in tumor progression. However, TAMs often occurs with unknown mechanisms. As an important mediator in intercellular communications, exosomes secreted by host cells mediate the exchange of genetic materials and proteins, which involves tumor aggressiveness.The aim of the study was to investigate whether exosomes derived from TAMs mediate stem cell properties in HCC. TAMs were isolated from the tissues of HCC. microRNA (miRNA) expression profiles of TAMs were analyzed using miRNA microarray. In vitro cell coculture was further conducted to investigate the crosstalk between TAMs and tumor cells mediated by TAMs exosomes. In this study, we showed that TAMs exosomes promote HCC cell proliferation and stem cell properties. Using miRNA profiles assay, we identified significantly lower levels of miR-125a and miR-125b in exosomes and cell lysate isolated from TAMs.Functional studies revealed that the HCC cells were treated with TAM exosomes or transfected with miR-125a/b suppressed cell proliferation and stem cell properties by targeting CD90, a stem cell marker of HCC stem cells. The study indicated that miR-125a/b targeting CD90 played important roles in cancer stem cells of HCC. K E Y W O R D S cancer stem cell (CSC), CD90, hepatocellular carcinoma (HCC), macrophages, miR-125a, miR-125b J Cell Biochem. 2019;120:3046-3055. wileyonlinelibrary.com/journal/jcb How to cite this article: Wang Y, Wang B, Xiao S, Li Y, Chen Q. miR-125a/b inhibits tumorassociated macrophages mediated in cancer stem cells of hepatocellular carcinoma by targeting CD90. J Cell Biochem. 2019;120:3046-3055.