Background: Tribbles homolog 3 (TRIB3) is a pseudokinase involved in the regulation of several signaling pathways involved in cell survival and/or cell stress. Here, we determined the correlation between breast cancer prognosis and TRIB3 protein levels and established the role of TRIB3 in cell survival after hypoxia and/or radiotherapy.
Material and methods: TRIB3 mRNA and protein were quantified in a new independent breast cancer patient cohort using QPCR and a new specific avian antibody against TRIB3. In addition, we used siRNA-mediated knockdown of TRIB3 in a colony-forming assay after hypoxia and radiotherapy.
Results: TRIB3 mRNA and protein levels did not correlate in breast cancer cell lines or human breast cancer material. We validated our earlier finding that high TRIB3 mRNA denotes a poor prognosis, but found that high TRIB3 protein levels were associated with a good prognosis in breast cancer patients. We also show that knockdown of TRIB3 resulted in an increased survival under hypoxic conditions.
Conclusion: Whereas mRNA levels of TRIB3 are related with a poor prognosis, TRIB3 protein is associated with a good prognosis in human breast cancer patients, possibly due to the fact that TRIB3 is involved in hypoxia tolerance.
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