Effect of different concentrations of oxygen on expression of sigma 1 receptor and superoxide dismutases in human colon adenocarcinoma cell lines.
BACKGROUND
Tumor cells due to distance from capillary vessels exist in different oxygenation conditions (anoxia, hypoxia, normoxia). Changes in cell oxygenation lead to reactive oxygen species production and oxidative stress. Sigma 1 receptor (Sig1R) is postulated to be stress responding agent and superoxide dismutases (SOD1 and SOD2) are key antioxidant enzymes. It is possible that they participate in tumor cells adaptation to different concentrations of oxygen.


OBJECTIVE
Evaluation of Sig1R, SOD1, and SOD2 expression in different concentrations of oxygen (1%, 10%, 21%) in colon adenocarcinoma cell lines.


METHODS
SW480 (primary adenocarcinoma) and SW620 (metastatic) cell lines were cultured in standard conditions in Dulbecco's modified Eagle's medium for 5 days, and next cultured in Hypoxic Chamber in 1% O2, 10% O2, 21% O2. Number of living cells was determined by trypan blue assay. Level of mRNA for Sig1R, SOD1, and SOD2 was determined by standard PCR method. Statistical analysis was conducted using Statistica 10.1 software.


RESULTS
We observed significant changes in expression of Sig1R, SOD1, SOD2 due to different oxygen concentrations. ANOVA analysis revealed significant interactions between studied parameters mainly in hypoxia conditions in SW480 cells and between Sig1R and SOD2 in SW620 cells. It also showed that changes in expression of studied proteins depend significantly on type of the cell line.


CONCLUSIONS
Changes of Sig1R and SOD2 expression point to mitochondria as main organelle responsible for survival of tumor cells exposed to hypoxia or oxidative stress. Studied proteins are involved in intracellular response to stress related with different concentrations of oxygen.
a Department of Biochemistry , Medical University of Warsaw , Warsaw , Poland.
Michał
M
Skrzycki
a Department of Biochemistry , Medical University of Warsaw , Warsaw , Poland.
Hanna
H
Czeczot
a Department of Biochemistry , Medical University of Warsaw , Warsaw , Poland.
Magdalena
M
Mielczarek-Puta
a Department of Biochemistry , Medical University of Warsaw , Warsaw , Poland.
Dagmara
D
Otto-Ślusarczyk
a Department of Biochemistry , Medical University of Warsaw , Warsaw , Poland.
Wojciech
W
Graboń
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000975:Antioxidants / Q000378:metabolism; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology; D010100:Oxygen / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D017480:Receptors, sigma / Q000096:biosynthesis* / Q000235:genetics; D013482:Superoxide Dismutase / Q000096:biosynthesis* / Q000235:genetics; D000072105:Superoxide Dismutase-1 / Q000096:biosynthesis* / Q000235:genetics; D000097605:Sigma-1 Receptor; D000099156:Superoxide Dismutase 2
D000975:Antioxidants; D010100:Oxygen; D017382:Reactive Oxygen Species; D017480:Receptors, sigma; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D000097605:Sigma-1 Receptor; D000099156:Superoxide Dismutase 2; C000606290:SOD1 protein, human
Hypoxia; calcium; oxidative stress; tumor