Altered Sirtuin 7 Expression is Associated with Early Stage Breast Cancer

Abstract

BACKGROUNDTo evaluate sirtuin-7 (SirT7) mRNA expression status in breast cancer patients with different metastatic stages and survey SirT7 mRNA expression status in eight different types of cancer.METHODSThe expression of SirT7 in the commercially available TissueScan qPCR Breast Cancer Disease cDNA arrays containing 16 normal, 23 Stage I, 36 IIA, 22 IIB, 8 IIIA, 23 IIIA, 6 IIIB, 13 IIIC, and 5 IV were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) assay. Similar analysis was performed in TissueScan qPCR Cancer Survey cDNA array, which includes breast, colon, kidney, liver, lung, ovarian, prostate, and thyroid specimens.RESULTSThe mRNA expression levels of SirT7 were significantly higher in breast cancer samples compared to normal breast specimens (P < 0.001). Stratification of patients into groups according to metastatic stages indicated statistically significantly higher levels of SirT7 mRNA in CS-I, CS-II, and CS-III when compared to normal breast tissue (P < 0.05). Notably, SirT7 mRNA levels were higher in CS-I, CS-IIA, CS-IIB, and CS-IIIA (P < 0.05). Additionally, there were significantly lower SirT7 mRNA levels in thyroid carcinoma when compared to their corresponding normal tissue (P < 0.05).CONCLUSIONSOur results indicate an increase in the mRNA expression level of SirT7 in breast cancer, particularly in CS-I, CS-IIA, CS-IIB, and CS-IIIA. The relationship of altered SirT7 with breast cancer progression and patient survival should be prospectively explored in future studies.

SIRT7 antagonizes TGF-β signaling and inhibits breast cancer metastasis

“…On the other side, Sirt7 are consistently downregulated in tumorigenic cells compared to non-tumorigenic ones in mice 44 , and SIRT7 is negatively correlated with progression of human head and neck squamous cell carcinoma 45 . Interestingly, Aljada et al 46 showed that SIRT7 is significantly upregulated in early stage of breast cancers but gradually declined with tumor progression. Indeed, oncogenic transformation, tumor growth, and metastasis are phenotypically distinct and mechanistically different processes.…”

Sirtuin 7: a new marker of aggressiveness in prostate cancer

“…Generally, sirtuins are considered to be tumor suppressors, but they may also act as tumor promoters particularly in advanced cancers [ 11 – 13 ]. Elevated levels of Sirt7 have been previously observed in several cancers including breast, liver, pancreas and colon [ 14 – 17 ]. SIRT7 is also associated with poor prognosis in gastric, lung, cervical and hepatocellular carcinoma [ 15 , 18 – 20 ].…”

MicroRNA-3666 inhibits breast cancer cell proliferation by targeting sirtuin 7

“…Ashraf et al (35) demonstrated that SIRT7 was significantly increased in breast cancer associated with node-positive breast cancer. Aljada et al (50) reported that high expression levels of SIRT7 were associated with early stage breast cancer (50). Furthermore, a high level of SIRT7 expression has been suggested as a predictor of adverse outcomes in breast cancer (36).…”