Modes of internalizations of human prostate carcinoma (DU145) cells in vitro and in murine xenotransplants

ABSTRACT

Ultrastructural data compiled from DU145 human prostate carcinoma cells growing in vivo and, more often in vitro or after treatment by pro-oxidant reactants, can induce and encompass several processes of cell internalization or entosis. These events were observed after tumor cells were essentially undergoing autoschizic injuries and other cell deaths without externalization of phosphatidylserine. Based on other previous observations made on DU145 cells, one hypothesizes that, as a means of survival, tumor cells find sources of nutrients through phagocytosis of apparently intact, injured cells, corpses, and cell debris by cannibalism. These peculiar activities occurred sporadically, in a small population of cells and could be dictated by their widely adapted energetic metabolism, now impaired, either due to the location of the cells in the growing tumors or in vitro as a result of this pro-oxidant anticancer treatment causing damage and abolishing their adapted metabolism.

KEYWORDS:

• Autoschizis
• cannibalism
• cell death
• cytophagosome
• entosis
• human prostatic carcinoma

Acknowledgments

This research was supported by the Summa Research Foundation, Akron, OH, USA; IC Med Tech, El Cajon, CA, USA; and St. George’s University School of Medicine, KBT Global Scholar’s Program where C. Ruffo contributed at a scholarly summer activity in the Department of Anatomical Sciences with J. Gilloteaux. Data were presented as invited at the Aegean Conferences, Rhodes (Greece) as part of the 2nd International Meeting of Clearance of Dying Cells and Debris in Healthy and Diseased Immune System, Oct 5–10, 2014 [68]. Kate Adamson, Northumbria University Graphics assisted in the electronic transfer of the illustrations.