Non-Professional Phagocytosis Increases in Melanoma Cells and Tissues with Increasing E-Cadherin Expression

• Published in: Current oncology (Toronto) 2023-08, Vol.30 (8), p.7542-7552
• Main Authors: Unseld, Luzie Helene, Hildebrand, Laura S, Putz, Florian, Büttner-Herold, Maike, Daniel, Christoph, Fietkau, Rainer, Distel, Luitpold Valentin
• Format: Article
• Language: English
• Subjects: Cadherins; cell cannibalism; cell-in-cell structures; E-cadherin; Humans; malignant melanoma; Melanoma; Melanoma, Cutaneous Malignant; Metastasis; non-professional phagocytosis; Phagocytosis; Skin; Skin Neoplasms
• ISSN: 1718-7729; 1198-0052; 1718-7729
• DOI: 10.3390/curroncol30080547

Non-professional phagocytosis in cancer has been increasingly studied in recent decades. In malignant melanoma metastasis, cell-in-cell structures have been described as a sign of cell cannibalism. To date, only low rates of cell-in-cell structures have been described in patients with malignant melanoma. To investigate these findings further, we examined twelve primary melanoma cell lines in both adherent and suspended co-incubation for evidence of engulfment. In addition, 88 malignant melanoma biopsies and 16 healthy tissue samples were evaluated. E-cadherin levels were determined in the cell lines and tissues. All primary melanoma cell lines were capable of phagocytosis, and phagocytosis increased when cells were in suspension during co-incubation. Cell-in-cell structures were also detected in most of the tissue samples. Early T stages and increasingly advanced N and M stages have correspondingly lower rates of cell-in-cell structures. Non-professional phagocytosis was also present in normal skin tissue. Non-professional phagocytosis appears to be a ubiquitous mechanism in malignant melanoma. The absence of phagocytosis in metastases may be one reason for the high rate of metastasis in malignant melanoma.