Effects of Unfertilized Egg White on Proliferation, Migration and Expression of Genes Linked to Stemness and Differentiation in SW480 Colon Cancer Cell Line

Embryonic cancers are very rare. However, the exact components preventing cancer development or progression in embryonic microenvironment are largely unknown. On the other hand, cancer stem cells with characteristics similar to embryonic stem cells are involved in cancer progression and resistance to treatment. The aim of this study was to investigate effects of unfertilized egg white, as an embryonic microenvironment model, on proliferation, self-renewal, stemness and migration of SW480 colon cancer cells and 5-fluorouracil (5FU) resistant subgroup.

In brief, SW480 and 5FU-SW480 cells were exposed to 10% (v/v) egg white. To assess viability, self-renewal and stemness characteristics and migratory capacity of the colon cancer cells, MTT, flow PI staining and flow cytometry, colony formation, spheroid and wound healing assays were used, respectively. Furthermore, expression levels of c-Myc, Nanog, Ndrg1 and E-cadherin genes were quantified using real-time polymerase chain reaction.

Findings showed that 10% volume of unfertilized egg white significantly decreased cell survival, inhibited cell cycle in G0/G1, decreased colony formation and sphere formation and inhibited migration ability in the two cell groups, compared to the control. Moreover, expression of c-Myc and Nanog decreased while expression of Ndrg1 and E-cadherin increased in SW480 cells. However, c-Myc gene expression increased in 5FU-SW480 with decreases in expression of Nanog and Ndrg1.

It seems that unfertilized egg white includes various mechanisms to control cancer development and progression. Further studies are needed to identify actual components affecting stemness and invasiveness of tumor cells, specifically cancer stem cells.