Research IndicatorsGraph generated 14 March 2017 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 14 March, 2017 using data from PubMed, MeSH and CancerIndex
Specific Cancers (7)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
GEO Profiles, NCBI
Search the gene expression profiles from curated DataSets in the Gene Expression Omnibus (GEO) repository.
Latest Publications: SIRT1 (cancer-related)
Jiang G, Wen L, Zheng H, et al.miR-204-5p targeting SIRT1 regulates hepatocellular carcinoma progression.
Cell Biochem Funct. 2016; 34(7):505-510 [PubMed
] Related Publications
Hepatocellular carcinoma (HCC) is the most common type of cancer, which presents rapid tumor growth, drug resistance, and metastasis. Recently, microRNAs are shown to be involved in the cell biological processes in HCC, but the underlying molecular mechanisms remain unclear. This study aimed to investigate the cellular function and molecular mechanism of miR-204-5p in HCC. SIRT1 mRNA and miR-204-5p were examined by real-time reverse transcription polymerase chain reaction. SIRT1 protein levels were measured by Western blotting. Cell proliferation assay was performed to confirm colony formation. Invasion assay was performed by transwell system. SPSS 15.0 for Windows was used for statistical analysis. SIRT1 was a potential oncogene in cancer, which was identified as a direct target of miR-204-5p. Overexpression of miR-204-5p in human HCC cell lines (BEL-7405 and QGY-7701) caused the suppression of cell survival ability, the increase of apoptosis, and drug sensitivity. SIRT1 was overexpressed in human HCC tissues and was negatively related to miR-204-5p levels. These results indicate that miR-204-5p and SIRT1 may play an important role in the development of HCC.
Shah AA, Ito A, Nakata A, Yoshida MIdentification of a Selective SIRT2 Inhibitor and Its Anti-breast Cancer Activity.
Biol Pharm Bull. 2016; 39(10):1739-1742 [PubMed
] Related Publications
SIRT2 is a member of the human sirtuin family of proteins and possesses nicotinamide adenine dinucleotide (NAD)-dependent lysine deacetylase activity. SIRT2 has been involved in various cellular processes including gene transcription, genome constancy, and the cell cycle. In addition, SIRT2 is deeply implicated in diverse diseases including cancer. In this study, we identified a small molecule inhibitor of SIRT2 with a structure different from known SIRT2 inhibitors by screening from a chemical library. The hit compound showed a high selectivity toward SIRT2 as it only inhibited SIRT2, and not other sirtuins including SIRT1 and SIRT3 or zinc-dependent histone deacetylases (HDACs) including HDAC1 and HDAC6, in vitro. The compound increased the acetylation level of eukaryotic translation initiation factor 5A (eIF5A), a physiological substrate of SIRT2, and reduced cell viability of human breast cancer cells accompanied with a decrease in c-Myc expression. These results suggest that the compound is cellular effective and has potential for development as a therapeutic agent against breast cancers by specific inhibition of SIRT2.
Hou Y, Wang F, Cheng L, et al.Expression Profiles of SIRT1 and APP Genes in Human Neuroblastoma SK-N-SH Cells Treated with Two Epigenetic Agents.
Neurosci Bull. 2016; 32(5):455-62 [PubMed
] Related Publications
In our previous studies, significant hypermethylation of the sirtuin 1 (SIRT1) gene and demethylation of the β-amyloid precursor protein (APP) gene were found in patients with Alzheimer's disease (AD) compared with the normal population. Moreover, the expression of SIRT1 was significantly decreased while that of APP was increased in AD patients. These results indicated a correlation of DNA methylation with gene expression levels in AD patients. To further investigate the epigenetic mechanism of gene modulation in AD, we used two epigenetic drugs, the DNA methylation inhibitor 5-aza-2'-deoxycytidine (DAC) and the histone deacetylase inhibitor trichostatin A (TSA), to treat human neuroblastoma SK-N-SH cells in the presence of amyloid β-peptide Aβ25-35(Aβ25-35). We found that DAC and TSA had different effects on the expression trends of SIRT1 and APP in the cell model of amyloid toxicity. Although other genes, such as microtubule-associated protein τ, presenilin 1, presenilin 2, and apolipoprotein E, were up-regulated after Aβ25-35 treatment, no significant differences were found after DAC and/or TSA treatment. These results support the evidence in AD patients and reveal a strong correlation of SIRT1/APP expression with DNA methylation and/or histone modification, which may help understand the pathogenesis of AD.
Chen Y, Chen J, Yun L, et al.Hydroquinone-induced malignant transformation of TK6 cells by facilitating SIRT1-mediated p53 degradation and up-regulating KRAS.
Toxicol Lett. 2016; 259:133-42 [PubMed
] Related Publications
Hydroquinone (HQ), known as one of the metabolic products of benzene, causes a number of hematologic malignancies. The study evaluated the potential mechanism of Sirtuin 1 (SIRT1) in HQ-induced TK6 cell malignant transformation. The data of our study show that short term exposure of TK6 cells to HQ led to a decrease expression of SIRT1. Knockdown of SIRT1 sensitized to the HQ-induced apoptosis in vitro and increased the expression of p53, p21 and γ-H2AX. Furthermore, chronic HQ-treated (20μM once a week for 19 weeks) caused carcinogenic transformation and was confirmed by abnormal cell proliferation, matrix metalloproteinase 9(MMP9) and subcutaneous tumor formation in nude mice. SIRT1 increased KRAS expression, and decreased H3K9 and H3K18 acetylation, inhibited p53 signaling and the level of caspase-3 in HQ-induced transformation cells. Taken together, these data suggest that SIRT1 is involved in HQ-induced malignant transformation associated with suppressing p53 signaling and activation of KRAS.
Igci M, Kalender ME, Borazan E, et al.High-throughput screening of Sirtuin family of genes in breast cancer.
Gene. 2016; 586(1):123-8 [PubMed
] Related Publications
Mammalian Sirtuins have been shown to perform distinct cellular functions and deregulated expression of these genes was reported to be involved in the development of various malignancies including breast cancer. An increasing number of evidence indicates that Sirtuins have both tumor promoter and tumor suppressor functions. However, the roles of Sirtuins have not been well-reported in breast cancer. In the present study, quantitative expression levels of Sirtuins (SIRT1-7) in breast cancer patients and breast cancer cell lines (MCF-7 and SKBR3) and control cell line (CRL-4010) were assessed by using a high-throughput real-time PCR method. As a result, Sirtuins were found to be differentially expressed in breast cancer tissues and cancer cell lines. Particularly, expressions of SIRT1 and SIRT4 were found to be significantly down-regulated in breast cancer tissues and SKBR3 breast cancer cells. In contrast, SIRT2, SIRT3, and SIRT5 genes were shown to be up-regulated in our study. Although SIRT6 and SIRT7 were also up-regulated in breast cancer tissues, these expression changes were statistically insignificant. Additionally, SIRT2, SIRT3, SIRT5, SIRT6 and SIRT7 were found to be differentially expressed in breast cancer cell lines. Yet, these changes were not well-correlated with tissue expression levels. In conclusion, Sirtuin family of genes shows differential expressions in breast cancer tissues and cells and SIRT1 and SIRT4 seem to play key tumor suppressor roles in breast cancer development. Herein, we report expression levels of Sirtuin family of genes in both breast cancer tissues and cancer cell lines simultaneously.
BACKGROUND: Breast cancer is reported to cause the highest mortality among female cancer patients. Previous studies have explored the association of silent mating-type information regulator 2 homolog 1 (SIRT1) gene expression with prognosis in breast cancer. However, no studies exist, so far, on the role of SIRT1 gene polymorphism in breast cancer risk or prognosis. The present study aimed to assess the association between SIRT1 gene polymorphisms and breast cancer in Egyptians.
METHODS: The study comprised 980 Egyptian females divided into a breast cancer group (541 patients) and a healthy control group (439 subjects). SIRT1 gene single nucleotide polymorphisms (SNPs) rs3758391, rs3740051 and rs12778366 were genotyped using real-time polymerase chain reaction (RT-PCR). Allelic and genotypic frequencies were determined in both groups and association with breast cancer and clinicopathological characteristics was assessed.
RESULTS: Breast cancer patients exhibited elevated serum SIRT1 levels which varied among different tumor grades. SIRT1 rs3758391 and rs12778366 TT genotypes were more frequent, exhibited higher SIRT1 levels than CC and CT genotypes and were associated with histologic grade and lymph node status. SIRT1 rs12778366 TT genotype also correlated with negative estrogen receptor (ER) and progesterone receptor (PR) statuses. The T allele frequency for both SNPs was higher in breast cancer patients than in normal subjects. Combined GG and AG genotypes of rs3740051 were more frequent, showed higher serum SIRT1 levels than the AA genotype, and were associated with ER and PR expression. Furthermore, inheritance of the G allele was associated with breast cancer.
CONCLUSIONS: Our findings reveal that rs3758391 and rs12778366 polymorphisms of SIRT1 gene are associated with breast cancer risk and prognosis in the Egyptian population.
Calgani A, Delle Monache S, Cesare P, et al.Leptin contributes to long-term stabilization of HIF-1α in cancer cells subjected to oxygen limiting conditions.
Cancer Lett. 2016; 376(1):1-9 [PubMed
] Related Publications
Leptin, a cytokine produced by the adipose tissue in response to food intake, is a key player in the regulation of energy balance and body weight control. Physiological action of leptin in modulating the metabolic adaptation of different peripheral tissues supports the hypothesis that it could also exert a direct effect on cancer cells. In vitro, treatment with leptin up-regulated HIF-1α and stimulated adhesion and invasion of prostate cancer cells cultured in hypoxia. Leptin action was effective in both low and high glycolytic cancer cell lines, and determined the up-regulation of lactate exporter MCT4 and its associated protein CD147. HIF-1α stabilization was oligomycin-independent and was associated with an important modulation of mitochondrial homeostasis. In fact, leptin treatment produced mitochondrial biogenesis, stabilization of mitochondrial membrane potential and increased uncoupled respiration through the up-regulation of UCP2. Furthermore, leptin counteracted the downmodulation of SIRT1 induced by hypoxia, and persistent high levels of SIRT1 were directly involved in HIF-1α stabilization. Leptin can sustain cancer progression in hypoxic environment and when mitochondrial respiration is impaired. Leptin signaling axis, including the new proposed intermediate SIRT1, could represent a new diagnostic and therapeutic target in prostate cancer.
Huang G, Cheng J, Yu F, et al.Clinical and therapeutic significance of sirtuin-4 expression in colorectal cancer.
Oncol Rep. 2016; 35(5):2801-10 [PubMed
] Related Publications
Several members of the sirtuin family (SIRT1-7), which are a highly conserved family of NAD+-dependent enzymes, play an important role in tumor formation. Recent studies indicate that SIRT4 acts as a tumor suppressor by regulating glutamine metabolism. In the present study, we investigated the expression and activity of SIRT4 in colorectal cancer. Using a tissue microarray of 89 colorectal cancer cases, we found that SIRT4 was significantly downregulated in colorectal cancer tissues compared with that noted in the corresponding normal tissue (P<0.001). Lower SIRT4 levels were associated with worse pathological differentiation (P=0.031) and poorer post-operative overall survival rate (P=0.041). We found that SIRT4 overexpression inhibited the proliferation of colorectal cancer cells in vitro and in vivo. SIRT4 inhibited the glutamine metabolism of colorectal cancer cells and synergistically with glycolysis inhibitors induced cell death. SIRT4 also increased the sensitivity of colorectal cancer cells to chemotherapeutic drug 5-fluorouracil by inhibiting the cell cycle. Together, these results highlight the prognostic value of SIRT4 in colorectal cancer and the potential application of SIRT4 in colorectal cancer treatment.
Cheng F, Su L, Yao C, et al.SIRT1 promotes epithelial-mesenchymal transition and metastasis in colorectal cancer by regulating Fra-1 expression.
Cancer Lett. 2016; 375(2):274-83 [PubMed
] Related Publications
Understanding molecular mechanisms of colorectal cancer (CRC) metastasis is urgently required for targeted therapy and prognosis of metastatic CRC. In this study, we explored potential effects of silent mating type information regulation 2 homolog 1 (SIRT1) on CRC metastasis. Our data showed that ectopic expression of SIRT1 markedly increased the migration and invasion of CRC cells. In contrast, silencing SIRT1 repressed this behavior in aggressive CRC cells. Tumor xenograft experiments revealed that knockdown of SIRT1 impaired CRC metastasis in vivo. Silencing SIRT1 in CRC cells induced mesenchymal-epithelial transition (MET), which is the reverse process of epithelial-mesenchymal transition (EMT) and characterized by a gain of epithelial and loss of mesenchymal markers. We provided a mechanistic insight toward regulation of Fra-1 by SIRT1 and demonstrated a direct link between the SIRT1-Fra-1 axis and EMT. Moreover, SIRT1 expression correlated positively with Fra-1 expression, metastasis and overall survival in patients with CRC. Taken together, our data provide a novel mechanistic role of SIRT1 in CRC metastasis, suggesting that SIRT1 may serve as a potential therapeutic target for metastatic CRC.
Sirt1 is a NAD⁺-dependent protein-modifying enzyme involved in regulating gene expression, DNA damage repair, metabolism and survival, as well as acts as an important subcellular target of resveratrol. The complex mechanisms underlying Sirt1 signaling during carcinogenesis remain controversial, as it can serve both as a tumor promoter and suppressor. Whether resveratrol-mediated chemopreventive effects are mediated via Sirt1 in CRC growth and metastasis remains unclear; which was the subject of this study. We found that resveratrol suppressed proliferation and invasion of two different human CRC cells in a dose-dependent manner, and interestingly, this was accompanied with a significant decrease in Ki-67 expression. By transient transfection of CRC cells with Sirt1-ASO, we demonstrated that the anti-tumor effects of resveratrol on cells was abolished, suggesting the essential role of this enzyme in the resveratrol signaling pathway. Moreover, resveratrol downregulated nuclear localization of NF-κB, NF-κB phosphorylation and its acetylation, causing attenuation of NF-κB-regulated gene products (MMP-9, CXCR4) involved in tumor-invasion and metastasis. Finally, Sirt1 was found to interact directly with NF-κB, and resveratrol did not suppress Sirt1-ASO-induced NF-κB phosphorylation, acetylation and NF-κB-regulated gene products. Overall, our results demonstrate that resveratrol can suppress tumorigenesis, at least in part by targeting Sirt1 and suppression of NF-κB activation.
Uveal melanoma (UM) is the most common intraocular malignancy in adults. Despite improvements in surgical, radiation and chemotherapy treatments, the overall survival of UM and prognosis remain poor. In the present study, we hypothesized that Sirtuin 1 and 2 (SIRT1/2), class III histone deacetylases (HDACs), were critical in controlling the destiny of bulk tumor cells and cancer stem cells (CSCs) of UM. We testified this hypothesis in four lines of UM cells (92.1, Mel 270, Omm 1 and Omm 2.3). Our results showed that inhibition of SIRT1/2 by Tenovin-6 induced apoptosis in UM cells by activating the expression of tumor suppressor genes such as p53 and elevating reactive oxygen species (ROS). Tenovin-6 inhibited the growth of UM cells. Tenovin-6 and vinblastine was synergistic in inducing apoptosis of UM cell line 92.1 and Mel 270. Furthermore, Tenovin-6 eliminated cancer stem cells in 92.1 and Mel 270 cells. In conclusion, our findings suggest that Tenovin-6 may be a promising agent to kill UM bulk tumor cells and CSCs.
Lattanzio F, Carboni L, Carretta D, et al.Treatment with the neurotoxic Aβ (25-35) peptide modulates the expression of neuroprotective factors Pin1, Sirtuin 1, and brain-derived neurotrophic factor in SH-SY5Y human neuroblastoma cells.
Exp Toxicol Pathol. 2016; 68(5):271-6 [PubMed
] Related Publications
The deposition of Amyloid β peptide plaques is a pathological hallmark of Alzheimer's disease (AD). The Aβ (25-35) peptide is regarded as the toxic fragment of full-length Aβ (1-42). The mechanism of its toxicity is not completely understood, along with its contribution to AD pathological processes. The aim of this study was to investigate the effect of the neurotoxic Aβ (25-35) peptide on the expression of the neuroprotective factors Pin1, Sirtuin1, and Bdnf in human neuroblastoma cells. Levels of Pin1, Sirtuin 1, and Bdnf were compared by real-time PCR and Western blotting in SH-SY5Y cells treated with Aβ (25-35) or administration vehicle. The level of Pin1 gene and protein expression was significantly decreased in cells exposed to 25 μM Aβ (25-35) compared to vehicle-treated controls. Similarly, Sirtuin1 expression was significantly reduced by Aβ (25-35) exposure. In contrast, both Bdnf mRNA and protein levels were significantly increased by Aβ (25-35) treatment, suggesting the activation of a compensatory response to the insult. Both Pin1 and Sirtuin 1 exert a protective role by reducing the probability of plaque deposition, since they promote amyloid precursor protein processing through non-amyloidogenic pathways. The present results show that Aβ (25-35) peptide reduced the production of these neuroprotective proteins, thus further increasing Aβ generation.
Breast cancer susceptibility gene 1 (BRCA1) is a tumor suppressor protein that functions to maintain genomic stability through critical roles in DNA repair, cell-cycle arrest, and transcriptional control. The androgen receptor (AR) is expressed in more than 70% of breast cancers and has been implicated in breast cancer pathogenesis. However, little is known about the role of BRCA1 in AR-mediated cell proliferation in human breast cancer. Here, we report that a high expression of AR in breast cancer patients was associated with shorter overall survival (OS) using a tissue microarray with 149 non-metastatic breast cancer patient samples. We reveal that overexpression of BRCA1 significantly inhibited expression of AR through activation of SIRT1 in breast cancer cells. Meanwhile, SIRT1 induction or treatment with a SIRT1 agonist, resveratrol, inhibits AR-stimulated proliferation. Importantly, this mechanism is manifested in breast cancer patient samples and TCGA database, which showed that low SIRT1 gene expression in tumor tissues compared with normal adjacent tissues predicts poor prognosis in patients with breast cancer. Taken together, our findings suggest that BRCA1 attenuates AR-stimulated proliferation of breast cancer cells via SIRT1 mediated pathway.
Since altered energy metabolism is a hallmark of cancer, many drugs targeting metabolic pathways are in active clinical trials. The tumor suppressor p53 is often inactivated in cancer, either through downregulation of protein or loss-of-function mutations. As such, stabilization of p53 is considered as one promising approach to treat those cancers carrying wild type (WT) p53. Herein, SIRT1 inhibitor Tenovin-1 and polo-like kinase 1 (Plk1) inhibitor BI2536 were used to stabilize p53. We found that both Tennovin-1 and BI2536 increased the anti-neoplastic activity of metformin, an inhibitor of oxidative phosphorylation, in a p53 dependent manner. Since p53 has also been shown to regulate metabolic pathways, we further analyzed glycolysis and oxidative phosphorylation upon drug treatments. We showed that both Tennovin-1 and BI2536 rescued metformin-induced glycolysis and that both Tennovin-1 and BI2536 potentiated metformin-associated inhibition of oxidative phosphorylation. Of significance, castration-resistant prostate cancer (CRPC) C4-2 cells show a much more robust response to the combination treatment than the parental androgen-dependent prostate cancer LNCaP cells, indicating that targeting energy metabolism with metformin plus p53 stabilizers might be a valid approach to treat CRPC carrying WT p53.
Li Y, Zhang J, He J, et al.MicroRNA-132 cause apoptosis of glioma cells through blockade of the SREBP-1c metabolic pathway related to SIRT1.
Biomed Pharmacother. 2016; 78:177-84 [PubMed
] Related Publications
BACKGROUND: The inhibition role of miRNA (microRNA or miR) on cancer signaling pathways has been used to prospective cancer treatment. SIRT1 might promote tumorigenesis in human glioma.
METHODS: Here, we investigated whether miR-132 regulate the expression of SIRT1 and its downstream SREBP (Sterol regulatory element-binding protein)-lipogenesis-cholesterogenesis metabolic pathway in human glioma cells. Furthermore, we studied the effect on biology function of glioma cell induced by miR-132.
RESULTS: MiR-132 inhibited SIRT1 and SREBP-1c expression and downregulated their targeted genes, including HMGCR and FASN. MiR-132 suppressed the cell growth, tumorigenicity, the invasion of glioma cells and migration as well as promoted their apoptosis. The pathways associated with cancer progression and tumorigenicity, and induce glioma cell apoptosis has been inhibited by miR-132 involving in a caspase-dependent apoptotic mechanism.
CONCLUSIONS: The recovery of miR-132 resulted in caspase-dependent apoptotic death in glioma cells. MiR-132 that was newly discovered represents a newly targeting mechanism in treatment for glioma.
Perumal D, Kuo PY, Leshchenko VV, et al.Dual Targeting of CDK4 and ARK5 Using a Novel Kinase Inhibitor ON123300 Exerts Potent Anticancer Activity against Multiple Myeloma.
Cancer Res. 2016; 76(5):1225-36 [PubMed
] Related Publications
Multiple myeloma is a fatal plasma cell neoplasm accounting for over 10,000 deaths in the United States each year. Despite new therapies, multiple myeloma remains incurable, and patients ultimately develop drug resistance and succumb to the disease. The response to selective CDK4/6 inhibitors has been modest in multiple myeloma, potentially because of incomplete targeting of other critical myeloma oncogenic kinases. As a substantial number of multiple myeloma cell lines and primary samples were found to express AMPK-related protein kinase 5(ARK5), a member of the AMPK family associated with tumor growth and invasion, we examined whether dual inhibition of CDK4 and ARK5 kinases using ON123300 results in a better therapeutic outcome. Treatment of multiple myeloma cell lines and primary samples with ON123300 in vitro resulted in rapid induction of cell-cycle arrest followed by apoptosis. ON123300-mediated ARK5 inhibition or ARK5-specific siRNAs resulted in the inhibition of the mTOR/S6K pathway and upregulation of the AMPK kinase cascade. AMPK upregulation resulted in increased SIRT1 levels and destabilization of steady-state MYC protein. Furthermore, ON123300 was very effective in inhibiting tumor growth in mouse xenograft assays. In addition, multiple myeloma cells sensitive to ON123300 were found to have a unique genomic signature that can guide the clinical development of ON123300. Our study provides preclinical evidence that ON123300 is unique in simultaneously inhibiting key oncogenic pathways in multiple myeloma and supports further development of ARK5 inhibition as a therapeutic approach in multiple myeloma.
BACKGROUND The epithelial-mesenchymal transition (EMT) has been shown to be involved in the process of invasion and metastasis of prostate cancer. SIRT1 is the mammalian homologue of the silent information regulator 2 (Sir2) gene, and is abnormally expressed in prostate cancer cells. Therefore, it is hypothesized that SIRT1 mediates the invasion/metastatic ability of prostate cancer via EMT regulation. This study thus investigated the effect of SIRT1 gene on the invasion and migration of prostate cancer cell line PC-3 via the small interference RNA (siRNA) against SIRT1. MATERIAL AND METHODS SiRNA construct was transfected into PC-3 cells, which were tested for the cell migration and invasion ability by scratch assay and Transwell migration assay, respectively. Expression levels of vimentin, E-cadherin, and N-cadherin were further quantified by Western blotting and RT-PCR. RESULTS Both mRNA and protein levels of SIRT1 were depressed after siRNA transfection, along with weakened migration and invasion ability of PC-3 cells. Elevated E-cadherin and suppressed N-cadherin and vimentin were observed in those transfected cells. CONCLUSIONS The silencing of SIRT1 gene in PC-3 cells can suppress the movement, migration, and invasion functions of prostate cancer cells, possibly via the down-regulation of mesenchymal markers vimentin and N-cadherin accompanied with up-regulation of epithelial marker N-cadherin, thus reversing the EMT process.
Sirtuins (SIRT) are nicotinamide adenine dinucleotide (NAD+) dependent deacetylases or ADP- ribosyl transferases (ARTs) that deacetylate lysine residues on various proteins regulating a variety of cellular and metabolic processes. These enzymes regulate metabolism, cell survival, differentiation and DNA repair. SIRT proteins play an important role in the survival and drug resistance of cancer cells. The purpose of the present study was to investigate the expression and role of SIRT in chronic lymphocytic leukemia (CLL). We analyzed the expression of SIRT1 and SIRT2 in CLL and normal B cells using the Oncomine database as well as by Western blotting of fresh CLL cells from patients and pro-lymphocytic leukemia (PLL) cell lines, JVM-3 and MEC-2. We showed that both primary CLL cells and JVM-3 and MEC-2 cell lines overexpress high levels of functional SIRT1 and SIRT2. SIRT inhibitors EX-527 and sirtinol impair cell growth, induce ROS production, loss of mitochondrial membrane potential and apoptosis in primary CLL cells and cell lines. Using shRNA knock down of SIRT1 and SIRT2 in JVM-3 and MEC-2 cell lines, we showed that expression of both proteins is crucial for the survival of these cells. Furthermore, studies in nutrient deprived conditions suggest a role of SIRT in metabolism in CLL. These results demonstrate that the inhibition of SIRT1 and SIRT2 activity may be a new therapeutic approach for CLL.
Quesada AE, Assylbekova B, Jabcuga CE, et al.Expression of Sirt1 and FoxP3 in classical Hodgkin lymphoma and tumor infiltrating lymphocytes: Implications for immune dysregulation, prognosis and potential therapeutic targeting.
Int J Clin Exp Pathol. 2015; 8(10):13241-8 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Hodgkin Reed-Sternberg (HRS) cells may promote differentiation of CD4+ naïve T cells toward both FoxP3+ T regulatory (Treg) cells and TIA-1+ cytotoxic T lymphocytes (CTL). Previous studies suggest that an overabundance of cytotoxic TIA-1+ cells in relation to FoxP3+ T reg cells portends unfavorable outcomes in classical Hodgkin lymphoma (cHL), raising the possibility that its pathogenesis may be related to immune dysregulation. Sirt1 deacetylates FoxP3 and leads to decreased Treg functionality. Our objective was to compare Sirt1 and FoxP3 expressions in Hodgkin lymphoma infiltrating lymphocytes (HLIL) and confirm Sirt1 expression in HRS cells.
DESIGN: Immunohistochemical staining of paraffin-embedded tissue with antibodies to Sirt1, FoxP3, TIA-1, and CD8 was performed. Expression of Sirt1 was assessed in both the HRS cells and in the HLILs in twenty-four cases. Adequate tissue was available in 13 cHL cases to permit the enumeration of FoxP3, TIA-1 and CD8 by giving their percent staining of HLILs.
RESULTS: In HLILs, nuclear expression of Sirt1 was 32-88% (mean 67%); FoxP3 expression was 9-40% (mean 23.9%); TIA-1 expression was 15-87% (mean 32%); and CD8 expression was 10-45% (mean = 31%). Sirt1 to FoxP3 ratio was 0.96-5.5 (mean 3.2). TIA-1 to FoxP3 ratio was 0.6-5.1 (mean 1.6). CD8 to FoxP3 ratio was 0.43-3.7 (mean 1.5). There was a difference of Sirt1 to FoxP3 ratios between remission and recurrence groups, being significantly higher in the recurrence group (P = 0.005). Sirt1 demonstrated high nuclear expression in the HRS cells of 21 out of 24 (88%) cases analyzed.
CONCLUSION: The relative overexpression of Sirt1 to FoxP3 in HLILs may be considered possible targets for immune modulation. Histone deacetylase inhibitors may increase the efficacy of existing treatment regimens by downregulating SIRT1 gene mRNA/Sirt1 protein function and together with rapamycin could expand the T regulatory/FoxP3 population and functionality and improve prognosis for remission in cHL. Targeting Sirt1 in the HRS cells may facilitate their ability to promote naïve T cell differentiation toward Treg cells over CTL.
Liu GF, Lu JY, Zhang YJ, et al.C/EBPα negatively regulates SIRT7 expression via recruiting HDAC3 to the upstream-promoter of hepatocellular carcinoma cells.
Biochim Biophys Acta. 2016; 1859(2):348-54 [PubMed
] Related Publications
Mammalian Sirtuin proteins (SIRTs) are homologs of yeast Sir2, and characterized as class III histone deacetylases of NAD(+) dependence. Unlike their lower counterparts that are directly involved in the extending of lifespan, mammalian SIRTs mainly function in metabolism and cellular homeostasis, among them, SIRT7 is the least understood. SIRT7 is localized in the nucleus and rich in nucleoli associated with RNA polymerase I, and correlated with cell proliferation. In contrast, SIRT7 has recently been demonstrated to specifically deacetylate H3K18ac in the chromatin, and in most cases represses proliferation. Although MicroRNA as miR-125b has been reported to down-regulate SIRT7 by binding to its 3'UTR, however, how SIRT7 gene is regulated remains unclear. Here, we identified the transcription initiation site of human SIRT7 gene at the upstream 23rd A nucleotide respective to the translational codon, and the SIRT7 is a TATA-less and initiator-less gene. The sequences in the upstream region between -256 and -129 bp are identical with important functions in the three species detected. A C/EBPα responding element is found that binds both C/EBPα and C/EBPβ in vitro. We showed TSA induced SIRT7 gene transcription and only the HDAC3, but not its catalytic domain depleted mutant, interacted with C/EBPα to occupy the C/EBPα element and repressed SIRT7 gene in the hepatocellular carcinoma cells. To our knowledge, this is the first report on the regulation mechanism of SIRT7 gene, in which, HDAC3 collaborated with C/EBPα to occupy its responding element in the upstream region of SIRT7 gene and repressed its expression in human cells.
Sirtuins participate in hormone imbalance, metabolism and aging, which are important processes for endometrial cancer (EC) development. Sirtuins mRNA expression (SIRT1 to 7) was determined in 76 ECs (63 Type I, 12 Type II and one mixed EC), and 30 non-neoplastic endometria (NNE) by quantitative real-time PCR. SIRT1 and SIRT7 protein expression was evaluated by immunohistochemistry using Allred score. Compared to NNE, ECs showed SIRT7 (p < 0.001) mRNA overexpression, whereas SIRT1 (p < 0.001), SIRT2 (p < 0.001), SIRT4 (p < 0.001) and SIRT5 (p < 0.001) were underexpressed. No significant differences were observed for SIRT3 and SIRT6. Type II ECs displayed lower SIRT1 (p = 0.032) and SIRT3 (p = 0.016) transcript levels than Type I ECs. Concerning protein expression, SIRT1 immunostaining median score was higher in ECs compared to NNE epithelium (EC = 5 vs. NNE = 2, p < 0.001), while SIRT7 was lower in ECs (EC = 6 vs. NNE = 7, p < 0.001). No significant associations were found between SIRT1/7 immunoexpression and histological subtype, grade, lymphovascular invasion or stage. Our data shows that sirtuins are deregulated in EC. The diversity of expression patterns observed suggests that sirtuins may have distinctive roles in endometrial cancer similarly to what has been described in other cancer models.
Sun H, McGuire MF, Zhang S, Brown RENUT Midline Carcinoma: Morphoproteomic Characterization with Genomic and Therapeutic Correlates.
Ann Clin Lab Sci. 2015; 45(6):692-701 [PubMed
] Related Publications
NUT midline carcinoma is a rare entity arising primarily in the midline of teenagers and young adults. Genomically, it is associated with a translocation involving a nuclear protein in testis (NUT) gene with other genes, most commonly, the BRD4 gene. The resultant is a partial or near total block in differentiation of tumor cells into mature squamous elements. Such tumors are resistant to conventional therapy with a reported mean survival at less than 1 year. In this study, we investigated two cases with genomic confirmation as NUT midline carcinoma by morphoproteomic analysis using immunohistochemical antibodies. Our results showed overexpression, largely in the undifferentiated cells of the tumors of: 1) Stemness marker, SRY (sex determining region Y)-box 2 (Sox2); 2) Constitutive activation of the mTORC2 pathway with expression of total insulin-like growth factor-1 receptor (IGF-1R[Tyr1165/1166]), and nuclear p-mTOR (Ser 2448) and p-Akt (Ser 473); and 3) c-Myc, silent mating type information regulation 2 homolog 1 (Sirt1) and histone methyltransferase enhancer of Zeste, Drosophila, homolog 2 (EZH2) as molecular impediments to differentiation. These data were analyzed through the use of QIAGEN's Ingenuity(®) Pathway Analysis (IPA(®), QIAGEN Redwood City, www.qiagen.com/ingenuity). The results established the interconnection of these pathways and molecules, and identified several pharmacogenomic agents--melatonin, metformin, vorinostat, curcumin, and sulforaphane--that have the potential to remove the block in differentiation and lead to the establishment of a more benign form of NUT midline carcinoma.
He Z, Yi J, Jin L, et al.Overexpression of Sirtuin-1 is associated with poor clinical outcome in esophageal squamous cell carcinoma.
Tumour Biol. 2016; 37(6):7139-48 [PubMed
] Related Publications
Sirtuin-1 (SIRT1), one member of the mammalian sirtuin family, has been suggested to play an essential role in the development and progression of many tumors. However, the relationship between expression of SIRT1 and prognosis of esophageal cancer is still unknown. This study aimed to investigate SIRT1 expression and its possible prognostic value in esophageal squamous cell carcinoma (ESCC). A total of 86 patients with ESCC were enrolled in our study group. Clinical data and matched tissues were collected. Western blotting and real-time quantitative reverse transcription PCR (RT-PCR) were carried out to explore the expression of SIRT1 in four human ESCC cell lines, one human normal epithelial cell line, and clinical ESCC tissues. Expression levels of SIRT1 protein in tissues of specimens were detected by immunohistochemistry (IHC). Survival analysis was carried out using the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were performed to evaluate the correlation of SIRT1 expression with clinical features and prognosis of ESCC patients. Basal expression levels of SIRT1 protein in ESCC tumor tissues and cell lines were higher than those in the control groups. IHC analysis showed that expression levels of SIRT1 protein significantly correlated with TNM stage and lymph node status of ESCC patients. Moreover, upregulated SIRT1 expression was associated with poor clinical prognosis. High SIRT1 expression in ESCC could serve as an independent predictive biomarker for diagnosis and prognosis in ESCC patients.
Chen H, Lu Q, Fei X, et al.miR-22 inhibits the proliferation, motility, and invasion of human glioblastoma cells by directly targeting SIRT1.
Tumour Biol. 2016; 37(5):6761-8 [PubMed
] Related Publications
Recently, microRNAs (miRNAs), a kind of small and non-coding RNA, can target the downstream molecules. Increasing evidence demonstrates that miRNAs meditate the onset and progression of a variety of tumors. In the present study, we carried out gene transfection, western blot, and reverse transcription PCR (RT-PCR) to explore the role of miR-22 in glioblastoma tissues and cell lines. Here, we verified that the expression of miR-22 was downregulated in glioblastoma tissues and cells rather than matched non-tumor tissues and normal human astrocyte (NHA) cells (p < 0.001). By contrast, SIRT1 messenger RNA (mRNA) and protein were upregulated in glioblastoma tissues and cells (p < 0.001). In vitro miR-22 mimics interfered with cell proliferation, migration, and invasion of U87 and U251 cells. Mechanically, the 3'-untranslated regions (3'-UTRs) of SIRT1 were a direct target of miR-22, leading to the decreased expression of SIRT1 protein in U87 and U251 cells. Meanwhile, miR-22 mimics also inhibited the expression of epidermal growth factor receptor (EGFR) and matrix metallopeptidase 9 (MMP9). In conclusion, miR-22 inhibited cell proliferation, migration, and invasion via targeting the 3'-UTR of SIRT1 in the progression of glioblastoma and miR-22-SIRT1 pathway can be recommended as a potential target for treatment of glioblastoma.
Temel M, Koç MN, Ulutaş S, Göğebakan BThe expression levels of the sirtuins in patients with BCC.
Tumour Biol. 2016; 37(5):6429-35 [PubMed
] Related Publications
Basal cell carcinoma (BCC) is the most common tumor in humans. Reduced expression of sirtuins interferes with DNA repair, which may cause mutations and genomic instability, and eventually leads to tumor development. In the present study, we investigate the expression levels of SIRT genes in non-tumoral and tumor tissues of patients with BCC. A total of 27 patients (16 males, 11 females) with BCC were included in the study; the mean age was 65.40 ± 10.74 years and mean follow-up was 2.5 ± 0.5 years. There were multiple synchronous lesions in six patients, and the remaining 21 patients had a single lesion. Tumor and non-tumoral tissue samples were collected from all patients, and mRNA expression levels of SIRT1-7 (Sirt1.1, Sirt1.2, Sirt2, Sirt3, Sirt4, Sirt5, Sirt6, and Sirt7) were examined by real-time PCR. The results showed that expressions of SIRT1.1, SIRT1.2, SIRT4, SIRT5, SIRT6, and SIRT7 mRNAs were unchanged in tumor tissues of BCC patients compared with non-tumoral tissue samples. Importantly, the expressions of SIRT2 and SIRT3 mRNAs were significantly reduced in tumor tissue samples from BCC patients compared with non-tumoral tissues (P = 0.02 and P = 0.03, respectively). In light of the previous reports that have demonstrated a link between SIRT proteins and cancer, our findings suggest that SIRT2 and SIRT3 may plan important roles in BCC pathogenesis and could be candidate prognostic biomarkers for BCC.
Manikandan M, Deva Magendhra Rao AK, Arunkumar G, et al.Down Regulation of miR-34a and miR-143 May Indirectly Inhibit p53 in Oral Squamous Cell Carcinoma: a Pilot Study.
Asian Pac J Cancer Prev. 2015; 16(17):7619-25 [PubMed
] Related Publications
BACKGROUND: Aberrant microRNA expression has been associated with the pathogenesis of a variety of human malignancies including oral squamous cell carcinoma (SCC). In this study, we examined primary oral SCCs for the expression of 6 candidate miRNAs, of which five (miR-34a, miR-143, miR-373, miR-380-5p, and miR- 504) regulate the tumor suppressor TP53 and one (miR-99a) is involved in AKT/mTOR signaling.
MATERIALS AND METHODS: Tumor tissues (punch biopsies) were collected from 52 oral cancer patients and as a control, 8 independent adjacent normal tissue samples were also obtained. After RNA isolation, we assessed the mature miRNA levels of the 6 selected candidates against RNU44 and RNU48 as endogenous controls, using specific TaqMan miRNA assays.
RESULTS: miR-34a, miR-99a, miR-143 and miR-380-5p were significantly down-regulated in tumors compared to controls. Moreover, high levels of miR-34a were associated with alcohol consumption while those of miR-99a and miR-143 were associated with advanced tumor size. No significant difference was observed in the levels of miR-504 between the tumors and controls whereas miR-373 was below the detection level in all but two tumor samples.
CONCLUSIONS: Low levels of miR-380-5p and miR-504 that directly target the 3'UTR of TP53 suggest that p53 may not be repressed by these two miRNAs in OSCC. On the other hand, low levels of miR-34a or miR-143 may relieve MDM4 and SIRT1 or MDM2 respectively, which will sequester p53 indicating an indirect mode of p53 suppression in oral tumors.
Ye Z, Fang J, Dai S, et al.MicroRNA-34a induces a senescence-like change via the down-regulation of SIRT1 and up-regulation of p53 protein in human esophageal squamous cancer cells with a wild-type p53 gene background.
Cancer Lett. 2016; 370(2):216-21 [PubMed
] Related Publications
MiR-34a has been reported as a non-coding RNA universally expressed in normal old cells and a probable suppressor of diverse cancer cells; however, this miRNA's expression and anti-tumor mechanism in esophageal squamous cancer cells (ESCC) remains unclear. We explored these questions in three human ESCC lines, KYSE-450, KYSE-410, and ECa-109, with wild-type p53 and mutant p53 backgrounds. Through a specific stem-loop RT primer for miR-34a, we examined the relevant expression level of miR-34a in these three cell lines using real-time reverse transcription PCR (qRT-PCR). We found that the expression level of miR-34a induced by the DNA damage agent adrmycin (ADR) was both p53- and time-dependent. Following incubation with miR-34a, cellular growth inhibition was exhibited differently in the three cell lines harbored with different p53 backgrounds. Furthermore, the MTT assay demonstrated an miR-34a-related cytotoxic effect in cell growth. Senescence-associated β-galactosidase (SA-β-Gal) staining was used to examine senescence-like phenotypes induced by miR-34a. Mechanistic investigation suggested that the down-regulation of Sirtuin1 (SIRT1) and up-regulation of p53/p21 contributed to the anti-tumor mechanism of miR-34a in wild-type p53 ECa-109 cells, while neither of the apoptosis-related proteins PARP and caspase-3 caused significant changes. In summary, our findings indicated that the intrinsic expression of miR-34a was relatively low and was expressed differently among different p53 backgrounds and ADR treatment times. The anti-tumor effect of miR-34a was primarily dependent on the regulation of SIRT1 and p53/p21 protein, not apoptosis-associated proteins.
Jin MS, Hyun CL, Park IA, et al.SIRT1 induces tumor invasion by targeting epithelial mesenchymal transition-related pathway and is a prognostic marker in triple negative breast cancer.
Tumour Biol. 2016; 37(4):4743-53 [PubMed
] Related Publications
Absence of therapeutic targets poses a critical hurdle in improving prognosis for patients with triple negative breast cancer (TNBC). We evaluated interaction between SIRT1 and epithelial mesenchymal transition (EMT)-associated proteins as well as the role of combined protein expression as a predictor of lymph node metastasis and clinical outcome in TNBC through in vivo and vitro studies. Three hundred nineteen patients diagnosed with TNBC were chosen, immunohistochemical staining for SIRT1 and EMT-related markers' expression was performed on tissue microarrays, and in vitro experiments with each of the three human TNBC cell lines were carried out. The cohort was reclassified according to the use of adjuvant chemotherapy, tumor size, and AJCC stage to analyze the prognostic role of SIRT1 and EMT-related proteins' expression considering different therapeutic modalities and AJCC stages. Combination of four proteins including SIRT1 and three EMT-related proteins was revealed to be a statistically significant independent predictor of lymph node metastasis in the tumor size cohort as well as in the total patient population. Upon Cox regression analysis, increased expression level of the combined proteins correlated with decreased disease-free survival in the total patients as well as those who received adjuvant chemotherapy and those who had early stage breast cancer. In additional in vitro experiments, inhibition of SIRT1 expression with small interfering RNA (siRNA) suppressed tumor invasion in three different TNBC cell lines, and altered expression levels of EMT-related proteins following SIRT1 gene inhibition were identified on western blotting and fluorescence activated cell sorting (FACS) analysis; on the other hand, no change in expression levels of the cell cycle-related factors was observed. Our analysis showed the potential role of SIRT1 in association with EMT-related factors on tumor invasion, metastasis, and disease-free survival in TNBC, SIRT1, and associated EMT-related markers may offer a new prognostic indicator as well as a novel therapeutic candidate.
Tumor cells with defective apoptosis pathways often respond to chemotherapy by entering irreversible cell cycle arrest with features of senescence. However, rare cells can bypass entry to senescence, or re-enter cell cycle from a senescent state. Deficiency in senescence induction and maintenance may contribute to treatment resistance and early relapse after therapy. Senescence involves epigenetic silencing of cell cycle genes and reduced rRNA transcription. We found that senescence-inducing treatments such as DNA damage and RNA polymerase I inhibition stimulate the binding between the nucleolar protein NML (nucleomethylin) and SirT1. The NML complex promotes rDNA heterochromatin formation and represses rRNA transcription. Depletion of NML reduced the levels of H3K9Me3 and H3K27Me3 heterochromatin markers on rDNA and E2F1 target promoters in senescent cells, increased rRNA transcription, and increased the frequency of cell cycle re-entry. Depletion of the nucleolar transcription repressor factor TIP5 also promoted escape from senescence. Furthermore, tumor tissue staining showed that breast tumors without detectable nucleolar NML expression had poor survival. The results suggest that efficient regulation of nucleolar rDNA transcription facilitates the maintenance of irreversible cell cycle arrest in senescent cells. Deficiency in nucleolar transcription repression may accelerate tumor relapse after chemotherapy.
Zhang S, Zhang D, Yi C, et al.MicroRNA-22 functions as a tumor suppressor by targeting SIRT1 in renal cell carcinoma.
Oncol Rep. 2016; 35(1):559-67 [PubMed
] Related Publications
Accumulating evidence demonstrates that microRNA-22 (miR-22) was deregulated in many types of cancers and was involved in various cellular processes related to carcinogenesis. However, the exact roles and mechanisms of miR-22 remain unknown in human renal cell carcinoma (RCC). Here, the relationship between miR-22 expression pattern and clinicopathological features of patients with EOC were determined by real-time quantitative RT-PCR (qRT-PCR). Furthermore, the role of miR-22 and possible molecular mechanisms in EOC were investigated by several in vitro approaches and in a nude mouse model. Results from qRT-PCR showed that miR-22 was significantly downregulated in RCC samples compared with corresponding non-cancerous tissues, which was significantly associated with tumor stage and lymph node metastasis. Functional study demonstrated that enforced overexpression of miR-22 in renal cancer cells inhibited proliferation, migration and invasion, and induced cell apoptosis in vitro, and suppressed tumor growth in vivo. In addition, SIRT1 was identified as a direct target of miR-22 by a luciferase reporter assay. Overexpression of miR-22 activated p53 and its downstream target p21 and PUMA, and the apoptosis markers cleaved CASP3 and PARP, and inhibited epithelial-mesenchymal transition (EMT). These findings showed that miR-22 functioned as tumor suppressor in RCC and blocked RCC growth and metastasis by directly targeting SIRT1 in RCC, indicating a potential novel therapeutic role in RCC treatment.