Selenite-induced apoptosis and autophagy in colon cancer cells.
Sodium selenite (Se) is known to induce diverse stress responses in malignant cells which may lead to various types of cell death including apoptosis and/or autophagy. In colon cancer cells, Se activates several signaling pathways whose interactions and ultimate endpoints may vary in individual study models. In our previous work we showed differences in Se-dependent growth inhibition, cell cycle alterations and apoptosis in colon cancer cells with functional (HCT-116) and deleted (HCT-116-p53KO) p53. Moreover, detailed morphological and biochemical analyses revealed the presence of autophagy in Se-treated cells. Thus the aim of this study was to investigate in detail mechanisms, relationship and crosstalk between apoptosis and autophagy in Se-treated HCT-116 cancer cells differing in p53 status since p53 has been shown to play a well-known role in apoptosis but dichotomous role in autophagy. We report that the absence of p53 in malignant colonocytes changes patterns of response to Se-induced stress which include differential activation of MAP kinases (p38 - HCT-116 and JNK - HCT-116 p53KO) including their respective roles in the process of apoptosis and autophagy as well as the involvement of mTOR or PI3K signaling. Our results seem to suggest that deletion of p53 inevitably leads to a higher level of instability and delays in an individual cell decision in the face of stress whether to activate apoptosis or autophagy which may consequently occur simultaneously with mutual dichotomous relationship.
Department of Medical Biology and Genetics, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
Věra
V
Králová
Soňa
S
Benešová
Miroslav
M
Cervinka
Emil
E
Rudolf
D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D004249:DNA Damage; D055785:Gene Knockdown Techniques; D045325:HCT116 Cells; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D018038:Sodium Selenite / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency* / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
D016588:Anticarcinogenic Agents; C494811:BCL2L1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D020928:Mitogen-Activated Protein Kinases; D018038:Sodium Selenite