Detecting cell-in-cell structures in human tumor samples by E-cadherin/CD68/CD45 triple staining

Abstract

Although Cell-in-cell structures (CICs) had been documented in human tumors for decades, it is unclear what types of CICs were formed largely due to low resolution of traditional way such as H&E staining. In this work, we employed immunofluorescent method to stain a panel of human tumor samples simultaneously with antibodies against E-cadherin for Epithelium, CD68 for Macrophage and CD45 for Leukocytes, which we termed as “EML method” based on the cells detected. Detail analysis revealed four types of CICs, with tumor cells or macrophage engulfing tumor cells or leukocytes respectively. Interestingly, tumor cells seem to be dominant over macrophage (93% vs 7%) as the engulfer cells in all CICs detected, whereas the overall amount of internalized tumor cells is comparable to that of internalized CD45+ leukocytes (57% vs 43%). The CICs profiles vary from tumor to tumor, which may indicate different malignant stages and/or inflammatory conditions. Given the potential impacts different types of CICs might have on tumor growth, we therefore recommend EML analysis of tumor samples to clarify the correlation of CICs subtypes with clinical prognosis in future researches.

Cell-in-cell structures are more potent predictors of outcome than senescence or apoptosis in head and neck squamous cell carcinomas

“…For instance, Huang et al identified four subtypes of CICs which could be formed homotypically among tumor cells or heterotypically between tumor cells and leukocytes. They also stated that macrophages could target live tumor cells to generate CICs [12]. As mentioned above, entosis is described a nonapoptotic cell death program in matrix-detached cells initiated by the invasion of one living cell into another [5].…”

Early Hyperbaric Oxygen Treatment Attenuates Burn-Induced Neuroinflammation by Inhibiting the Galectin-3-Dependent Toll-Like Receptor-4 Pathway in a Rat Model

“…Thus, MIF and CD68 can be used as markers to detect both M1 and M2 macrophages and reveal macrophage expression of the burninjury site [73,74]. After HBO treatment, the expression of TNF-α and IL-1β significantly decreased.…”

Macrophages are involved in cell-in-cell structures in human tumors

“…In a study on samples from six types of human tumors, Huang et al [4] analyzed the cell types involved in CICs in human tumors by the "EML" method, where immunofluorescent staining was performed with antibodies against E-cadherin, CD68 and CD45 for Epithelium, Macrophage and Leukocytes (EML), respectively. Consistent with the above classification, they identified both homotypic and heterotypic CICs, whose amounts were comparable (54% vs 46%).…”

“…Meanwhile, tumor-associated macrophages (TAM), a sub-population of macrophages derived from bone marrow, were found important players in tumor progression by influencing multiple processes including angiogenesis, tumor cell invasion, intravasation, extravasation and persistent growth and the like [3] . Recently, macrophages were demonstrated to be involved in the formation of a type of unique cellular structures called cell-in-cell structures (CICs) in human tumor samples [4] , which refreshes our views on the roles of macrophages in tumor biology and potentially provide a novel target for tumor therapy.…”

“…CICs are divided into homotypic CICs and heterotypic CICs according to the referred cell types [4,12] . Formation of homotypic CICs between cells of the same types, usually by entosis, requires cadherin-mediated cell-cell adhesion [6,13] and the activation of the Rho-ROCK-myosin II pathway [7,14] , which may mediate competition among human tumor cells and thus promote clonal selection and tumor evolution [7,15,16] .…”