Prognostic and clinicopathological significance of SIRT1 expression in NSCLC: a meta-analysis

Downregulation of circ-YES1 suppresses NSCLC migration and proliferation through the miR-142-3p-HMGB1 axis

BACKGROUND

Circular RNAs (circRNAs) are a new family of abundant regulatory RNAs with roles in various types of cancer. While the hsa_circ_0046701 (circ-YES1) function in non-small cell lung cancer (NSCLC) is unclear.

METHODS

Circ-YES1 expression in normal pulmonary epithelial and NSCLC cells was examined. The small interfering RNA for circ-YES1 was prepared, cell proliferation and migration were assessed. Tumorigenesis in nude mice was assayed to validate the role of circ-YES1. Bioinformatics analyses and luciferase reporter assays were utilized to identify downstream targets of circ-YES1.

RESULTS

Compared to normal pulmonary epithelial cells, the circ-YES1 expression increased in NSCLC cells, and cell proliferation and migration were suppressed after circ-YES1 knockdown. Both high mobility group protein B1 (HMGB1) and miR-142-3p were found to be downstream targets of circ-YES1, and miR-142-3p inhibition and HMGB1 overexpression reversed the effects of circ-YES1 knockdown on cell proliferation and migration. Similarly, HMGB1 overexpression reversed the miR-142-3p overexpression effects on these two processes. The imaging experiment results revealed that circ-YES1 knockdown impeded tumor development and metastasis in a nude mouse xenograft model.

CONCLUSION

Taken together, our results show that circ-YES1 promotes tumor development through the miR-142-3p-HMGB1 axis and support the development of circ-YES1 probability as a new therapeutic NSCLC target.

Ginsenoside CK Inhibits TGF-β-Induced Epithelial-Mesenchymal Transition in A549 Cell via SIRT1

Ginsenoside CK is the main metabolite of protopanaxadiol saponins in intestinal bacteria. Previous studies have shown that ginsenoside CK can affect many aspects of tumor development through a variety of mechanisms. However, few studies have reported the antimetastatic effects of ginsenoside CK in non-small-cell lung cancer (NSCLC). In this study, we explored the effect of ginsenoside CK on epithelial-mesenchymal transition (EMT) induced by TGF-β in A549 cells and the potential molecular mechanisms. Our data showed that ginsenoside CK effectively prevented TGF-β-induced EMT, as indicated by the upregulation of E-cadherin and downregulation of vimentin. Furthermore, ginsenoside CK inhibited the metastatic ability of A549 cells in the tail vein lung metastasis model of nude mice. Additionally, ginsenoside CK decreased the expression of silent information regulator 2 homolog 1 (SIRT1) in the inhibition of EMT induced by TGF-β. Moreover, the antimetastatic effect of ginsenoside CK was reversed by SIRT1 overexpression. Generally, our results indicated the antimetastatic effect and underlying mechanism of ginsenoside CK on TGF-β-induced EMT in A549 cells, suggesting that ginsenoside CK can be used as an effective antineoplastic agent.

SIRT1/PGC-1α/PPAR-γ Correlate With Hypoxia-Induced Chemoresistance in Non-Small Cell Lung Cancer

Resistance is the major cause of treatment failure and disease progression in non-small cell lung cancer (NSCLC). There is evidence that hypoxia is a key microenvironmental stress associated with resistance to cisplatin, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), and immunotherapy in solid NSCLCs. Numerous studies have contributed to delineating the mechanisms underlying drug resistance in NSCLC; nevertheless, the mechanisms involved in the resistance associated with hypoxia-induced molecular metabolic adaptations in the microenvironment of NSCLC remain unclear. Studies have highlighted the importance of posttranslational regulation of molecular mediators in the control of mitochondrial function in response to hypoxia-induced metabolic adaptations. Hypoxia can upregulate the expression of sirtuin 1 (SIRT1) in a hypoxia-inducible factor (HIF)-dependent manner. SIRT1 is a stress-dependent metabolic sensor that can deacetylate some key transcriptional factors in both metabolism dependent and independent metabolic pathways such as HIF-1α, peroxisome proliferator-activated receptor gamma (PPAR-γ), and PPAR-gamma coactivator 1-alpha (PGC-1α) to affect mitochondrial function and biogenesis, which has a role in hypoxia-induced chemoresistance in NSCLC. Moreover, SIRT1 and HIF-1α can regulate both innate and adaptive immune responses through metabolism-dependent and -independent ways. The objective of this review is to delineate a possible SIRT1/PGC-1α/PPAR-γ signaling-related molecular metabolic mechanism underlying hypoxia-induced chemotherapy resistance in the NSCLC microenvironment. Targeting hypoxia-related metabolic adaptation may be an attractive therapeutic strategy for overcoming chemoresistance in NSCLC.

Prognostic role of SIRT6 in gastrointestinal cancers: a meta-analysis

Sirtuin 6 (SIRT6) plays a critical role in the progression and development of gastrointestinal cancers. However, the association between SIRT6 expression and clinicopathological parameters and prognosis in gastrointestinal cancer patients remains inconclusive. Consequently, we conducted this meta-analysis to evaluate the importance of SIRT6 expression in various types of gastrointestinal cancers. PubMed, EMBASE, and Web of Science databases were systematically searched to screen the relevant literature. The reported or estimated hazard ratio (HR) and odds ratio (OR) and their corresponding 95% confidence interval (CI) were pooled to assess the strength of the association. Nine studies involving 867 patients were included in the meta-analysis. Overall analysis showed that high SIRT6 expression was related to better overall survival in gastrointestinal cancers (HR = 0.62, 95% CI = 0.47–0.82). High SIRT6 expression was also related to a favorable tumor node metastasis (TNM) stage (OR = 0.44, 95% CI = 0.28–0.70) among gastrointestinal cancer patients. Our meta-analysis revealed that high SIRT6 expression might be a potential biomarker predicting better prognosis in gastrointestinal cancers, which may offer options for gastrointestinal cancer treatment.

Sirtuin1 expression and survival in endometrial and clear-cell uterine cancer

Several risk factors like obesity and hyperlipidemia were described for endometrial cancer. Here, the nuclear NAD-dependent histone-deacetylase Sirtuin1 (SIRT1) seems to be important. SIRT1 is also involved in cell regulatory mechanisms and can serve as tumor promotor or suppressor. Its role in tumor biology is not clear yet. In this study, we evaluated and correlated the SIRT1 expression with patients’ tumor characteristics in endometrioid and clear-cell cancer of the uterus. 65 paraffin-embedded samples of patients with endometrial and clear-cell cancer of the uterus were immunohistochemically stained and SIRT1 expression was evaluated by immunoreactive score. The results were correlated to clinical and pathological tumor characteristics as well as to the expression of ARID1A and β-Catenin. The staining was significantly more intensive in uterine endometrioid carcinoma compared to uterine clear-cell carcinoma (p = 0.007). The expression of SIRT1 correlated significantly with the membranous expression of β-Catenin (p = 0.028) and ARID1A (p = 0.021). Patients with positive Sirtuin1 expression had a significantly better progression-free survival (p = 0.042), the overall survival showed a trend towards a better prognosis (p = 0.070). SIRT1 expression seems to be associated with improved progression-free survival in uterine cancer (endometrioid and clear-cell) and is correlated to the tumor suppressors β-Catenin and ARID1A. Further studies are necessary to elucidate the role of SIRT1 in uterine and ovarian cancer and its potential as a therapeutic target.

CircRNA hsa_circ_0087862 Acts as an Oncogene in Non-Small Cell Lung Cancer by Targeting miR-1253/RAB3D Axis

Purpose

Circular RNAs (circRNAs) have been found to regulate several human tumors. The present study was to explore the mechanism of hsa_circ_0087862 in regulating non-small cell lung cancer (NSCLC).

Methods

Totally 102 NSCLC cases were enrolled. NCI-H1359 and A549 cells were transfected. Cells viability, apoptosis, migration and invasion were determined by CCK-8 assay, flow cytometry, scratch test and transwell experiment, respectively. Luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were performed. Xenograft tumor experiments were performed using nude mice. hsa_circ_0087862, miR-1253 and RAB3D expression in tissues/cells were detected by qRT-PCR. RAB3D and Ki67 protein expressions in cells/tissues were researched by Western blot and immunohistochemistry. Apoptosis of xenograft tumor tissue cells was detected using Tunel assay.

Results

hsa_circ_0087862 was significantly up-regulated in NSCLC patients, which was associated with poor prognosis (P < 0.05). hsa_circ_0087862 down-regulation prominently weakened NSCLC cells viability, migration, invasion and enhanced apoptosis (P < 0.01). hsa_circ_0087862 overexpression exhibited the opposite results in NSCLC cells. miR-1253 was sponged by hsa_circ_0087862. miR-1253 expression in NSCLC tissues was negatively correlated with hsa_circ_0087862 (P < 0.001). RAB3D expression in NSCLC was directly inhibited by miR-1253. miR-1253 down-regulation or RAB3D overexpression dramatically reversed NSCLC cells phenotype induced by hsa_circ_0087862 down-regulation. hsa_circ_0087862 down-regulation markedly inhibited tumor growth in vivo (P < 0.01). In xenograft tumor tissues, hsa_circ_0087862 down-regulation obviously decreased expression of RAB3D, Ki67 and increased apoptosis.

Conclusion

hsa_circ_0087862 acted as an oncogene in NSCLC by targeting miR-1253/RAB3D.

miR-448 promotes progression of non-small-cell lung cancer via targeting SIRT1

Deregulation of microRNAs (miRs) has been demonstrated to be involved in both the initiation and the development of non-small-cell lung cancer (NSCLC). miR-448 has been identified as a tumor suppressor in several cancer types. The aim of the present study was to explore the role of miR-448 in NSCLC. Tumor tissues and paired normal tissues were obtained from patients with NSCLC. The viability and migration of A549 cells were determined by the Cell Counting kit-8 and wound-healing assays, respectively. Gene and protein levels were detected by reverse transcription-quantitative polymerase chain reaction analysis and western blotting, respectively. The interaction between the 3' untranslated region of sirtuin1 (SIRT1) and miR-448 was predicted by TargetScan and verified by dual luciferase reporter assay. miR-448 levels were revealed to be decreased whereas SIRT1 levels were increased in NSCLC tissues compared with normal tissues. Pearson's correlation analysis demonstrated that there was a negative correlation between miR-448 and SIRT1 mRNA levels. Overexpression of miR-448 led to reduced growth and migration ability of A549 cells. In addition, overexpression of miR-448 decreased SIRT1 mRNA and protein levels, thereby inhibiting epithelial-mesenchymal transition (EMT) and affecting EMT-associated molecules, including vimentin and E-cadherin. Dual luciferase reporter assay confirmed that SIRT1 was a direct target of miR-448. Notably, activation of SIRT1 by resveratrol treatment partially reversed the cell growth inhibition induced by miR-448 mimics. These findings suggested that the progression of NSCLC may be controlled by miR-448, which appears to hold promise as a therapeutic target for patients with NSCLC.

20(S)-Protopanaxadiol Inhibits Angiotensin II-Induced Epithelial- Mesenchymal Transition by Downregulating SIRT1

20(S)-Protopanaxadiol (PPD) is one of the major active metabolites in ginseng saponin. Our previous studies revealed a broad spectrum of antitumor effects of PPD. Angiotensin II (Ang II), the biologically active peptide of the renin-angiotensin system (RAS), plays a critical role in the metastasis of various cancers. However, its role in the anti-metastatic effects of PPD is not clearly understood. In this study, we investigated the inhibitory effect of PPD on Ang II-induced epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells, and the potential molecular mechanisms of suppression of NSCLC migration and metastasis by PPD. Treatment of A549 cells with Ang II increased metastases in an experimental model of cancer metastasis in vivo. PPD effectively prevented Ang II-induced EMT, as indicated by upregulation of E-cadherin and downregulation of vimentin. Additionally, Ang II upregulated the class III deacetylase sirtuin 1 (SIRT1) expression in EMT progression, while downregulation of SIRT1 was involved in suppression of Ang II-induced EMT by PPD. Moreover, the inhibitory effect of PPD was reversed by SIRT1 upregulation, and PPD demonstrated synergy with an SIRT1 inhibitor on Ang II-induced EMT. Taken together, our data reveal the mechanism of the anti-metastatic effects of PPD on Ang II-induced EMT and indicate that PPD can be used as an effective anti-tumor treatment.

Associations of sirtuins with clinicopathological parameters and prognosis in non-small cell lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer-related death worldwide and it is critical to discover specific biomarkers to provide better individualized treatment and subsequently better prognosis. The sirtuins (SIRT1-7) have been reported to be involved in cancers including non-small cell lung cancer (NCSLC), however, the results are not consistent and not all the seven sirtuins are explored and compared.

METHODS

TCGA data was downloaded and used to investigate and compare the associations of sirtuins mRNA levels with clinicopathological parameters and prognosis in NSCLC.

RESULTS

Our results suggested SIRT1, SIRT3, SIRT4, and SIRT7 were highly expressed in adeno-carcinoma (ADC) patients and female patients while SIRT5 were highly expressed in squamous cell carcinoma (SCC) patients and male patients. Associations of high SIRT7 with younger onset age, high SIRT1 with distant metastasis and low T stage, and high SIRT4 with high T stage and TNM stage were also found. Kaplan-Meier plot curves and univariate Cox proportional regression analyses indicated that high SIRT2, SIRT4, and SIRT6 expressions were associated with longer overall survival (OS) time. Multivariate analyses indicated that SIRT2 and SIRT6 were still associated with OS. For recurrence-free survival (RFS), high SIRT1 expression was significantly associated with shorter RFS time while high SIRT2-3 and SIRT5-7 expressions were associated with longer RFS time in univariate analyses. After adjusting the confounding factors, significant associations were still found in SIRT1-2 and SIRT5-7 but not in SIRT3. We also stratified the patients by combining SIRT1 and SIRT2 and revealed that the combination of SIRT1 and SIRT2 was a better prediction model for RFS in NSCLC. To preliminarily understand the potential mechanisms of sirtuins in NSCLC carcinogenesis, the genes co-expressed with sirtuins were analyzed and annotated.

CONCLUSION

sirtuins might be the potential therapy targets and prognostic biomarkers in NSCLC.

Association of sirtuins with clinicopathological parameters and overall survival in gastric cancer

To evaluate the associations of sirtuins (SIRT1-7) with clinicopathological parameters in gastric cancer, sirtuins expression profile in NCBI GEO datasets, GSE62254 and GSE15459, was integrated and analyzed. The results suggested that SIRT4, SIRT6, and SIRT7 were associated with Lauren classification and SIRT3-5 were associated with pStage in gastric cancer. Then an online database derived from 1,065 gastric cancer cases, Kaplan-Meier plotter, was used to explore the associations of the mRNA levels of sirtuins with overall survival in gastric cancer. Survival curves generated from Kaplan-Meier plotter suggested that high expression of SIRT1 mRNA was favorable for overall survival in gastric cancer (SIRT1: HR = 0.64, 95% CI = 0.54–0.76, P = 2.2E-07), high expressions of SIRT2-4 and SIRT6-7 were poor for overall survival (SIRT2: HR = 2.31, 95% CI = 1.87–2.87, P = 3.6E-15; SIRT3: HR = 1.99, 95% CI = 1.62–2.45, P = 2.6E-11; SIRT4: HR = 1.41, 95% CI = 1.19–1.68, P = 6.6E-05; SIRT6: HR = 2.02, 95% CI = 1.66–2.47, P = 1.7E-12; SIRT7: HR = 1.96, 95% CI = 1.63–2.35, P = 2.7E-13), whereas no significant association existed between SIRT5 mRNA expression and overall survival. Further analyses stratified by gender, stages, Lauren classification, differentiation, treatment, and HER2 status were also performed. In summary, high SIRT1 mRNA level was associated with better overall survival, SIRT2-4 and 6–7 were associated with poor overall survival, whereas SIRT5 did not show significant association with overall survival in gastric cancer.