SuperSAGE evidence for CD14++CD16+ monocytes as a third monocyte subset

Abstract

Monocytes are a heterogeneous cell population with subset-specific functions and phenotypes. The

Chemotherapy of colorectal liver metastases induces a rapid rise in intermediate blood monocytes which predicts treatment response

“…11,12 Highest TNFa expression was found in non-classical monocytes, consistent with a strong pro-inflammatory potential. HLA-DR and CCR5 were both expressed at highest levels in the intermediate subset, indicating a pronounced role in antigen-presentation as well as chemotactic response to tumor signals, respectively.…”

“…While the low and uniform levels of VEGF transcripts were unexpected, all other results were in line with previously published reports on gene expression patterns of monocyte subsets. 11,12 Importantly, there were no significant differences in the gene expression profiles between monocyte subsets isolated from healthy controls and mCRC patients, even though we have previously shown that the frequency of subpopulations differs significantly between healthy individuals and mCRC patients. 16 Furthermore, chemotherapy did not alter the gene expression profile of monocyte subsets in mCRC patients.…”

“…23 However, the role of monocytes and particular subpopulations in the tumor setting is not fully understood. Microarray studies by Zawada et al 12 have linked the subset of intermediate monocytes to pro-inflammatory as well as proangiogenic properties. Therefore, their role in malignant disease seems ambiguous, as this subset is capable of stimulating tumor angiogenesis on the one hand, but may also exert antitumor effects on the other hand by the production of pro-inflammatory cytokines such as TNF-a, IL-1b and IL-6 and by antigen presentation.…”

“…10 Recent studies on the gene expression profile of monocyte subsets have suggested a developmental relationship between these populations with gradual changes in surface markers during maturation. 11,12 In accordance, the non-classical subset may represent the most progressed stage of differentiation.…”

“…11,12 Non-classical monocytes (5%) exhibit a "patrolling" behavior i.e. crawling along vessel walls to screen for integrity 13 and they react strongly to viral signals.…”