Downregulated expression of hsa_circ_0037515 and hsa_circ_0037516 as novel biomarkers for non-small cell lung cancer.

Circular RNAs (circRNAs) represent a class of endogenous non-coding RNAs. Recently, it has been reported that circRNAs might serve as novel potential biomarkers for the diagnosis of cancer, including non-small cell lung cancer (NSCLC). Mutations in the ATP binding cassette subfamily A member 3 (ABCA3) have been increasingly associated with lung disease; however, roles for circRNAs at the ABCA3 locus have not been identified. To characterize novel biomarkers in NSCLC, a bioinformatics platform was used to select circRNAs within the ABCA3 gene. Divergent primers were designed for hsa_circ_0037515 and hsa_circ_0037516, and the PCR products were sequenced to verify their existence in lung tissue. To evaluate diagnostic potential, expression levels of hsa_circ_0037515, hsa_circ_0037516, and ABCA3 were measured by quantitative reverse transcription-polymerase chain reaction; differences in expression levels were analyzed using the paired t-test, and receiver operating characteristic (ROC) curves were established. Our results demonstrate that ABCA3 mRNA, hsa_circ_0037515, and hsa_circ_0037516 are significantly downregulated in 61 paired samples of NSCLC compared to adjacent lung tissues (P < 0.01), and that the areas under the ROC curves for the two circRNAs (0.81 and 0.82, respectively) are indicative of diagnostic value. Furthermore, the significance was improved by considering the two circRNAs in combination (area under the ROC curve, 0.90). Our results suggest that hsa_circ_0037515 and hsa_circ_0037516 serve as novel potential biomarkers for the diagnosis of NSCLC.

Epigenetic silencing of ZNF132 mediated by methylation-sensitive Sp1 binding promotes cancer progression in esophageal squamous cell carcinoma.

Epigenetic alteration of tumor suppression gene is one of the most significant indicators in human esophageal squamous cell carcinoma (ESCC). In this study, we identified a novel ESCC hypermethylation biomarker ZNF132 by integrative computational analysis to comprehensive genome-wide DNA methylation microarray dataset. We validated the hypermethylation status of ZNF132 in 91 Chinese Han ESCC patients and adjacent normal tissues with methylation target bisulfite sequencing (MTBS) assay. Meanwhile, ZNF132 gene silencing mediated by hypermethylation was confirmed in both solid tissues and cancer cell lines. What is more, we found that in vitro overexpression of ZNF132 in ESCC cells could significantly reduce the abilities of the cell in growth, migration and invasion, and tumorigenicity of cells in a nude mouse model. We validated the Sp1-binding site in the ZNF132 promoter region with chromatin immunoprecipitation assay and demonstrated that the hypermethylation status could reduce the Sp1 transcript factor activity. Our results suggest that ZNF132 plays an important role in the development of ESCC as a tumor suppressor gene and support the underlying mechanism caused by the DNA hypermethylation-mediated Sp1-binding decay and gene silencing.

Clofoctol and sorafenib inhibit prostate cancer growth via synergistic induction of endoplasmic reticulum stress and UPR pathways.

BACKGROUND/PURPOSE: Prostate cancer is a major burden on public health and a major cause of morbidity and mortality among men worldwide. Drug combination therapy is known as a powerful tool for the treatment of cancer. The aim of this study is to evaluate the synergistic inhibitory mechanisms of clofoctol and sorafenib in the treatment of prostate cancer. However, the molecular mechanisms of this phenomenon have not been illuminated clearly. In this study, we investigated the anti-tumor effects of clofoctol in combination with sorafenib in vitro and in vivo. METHODS: The activity and mechanism of clofoctol in combination with sorafenib were examined in PC-3cells. mRNA and protein expression of key players in the ER stress pathway were detected with RT-PCR and Western blotting. Cell viability was estimated by CCK-8 assay or Alamar blue assay, and apoptosis and cell cycle were monitored and measured by flow cytometry. PC-3 cells were inoculated subcutaneously in male BALB/c nude mice. The therapeutic regimen was initiated when the tumor began showing signs of growth and treatment continued for 5 weeks. RESULTS: Our data indicate that clofototol and sorafenib induce cell death through synergistic induction of endoplasmic reticulum (ER) stress, resulting in activation of the unfolded protein response (UPR). Combination therapy with clofoctol and sorafenib induced an upregulation of markers of all three ER stress pathways: PERK, IRE1 and ATF6. In addition, combination therapy with clofoctol and sorafenib markedly inhibited the growth of prostate cancer xenograft tumors, compared with clofoctol or sorafenib alone. CONCLUSION: The combination of clofoctol and sorafenib can serve as a novel clinical treatment regimen, potentially enhancing antitumor efficacy in prostate cancer and decreasing the dose and adverse effects of either clofoctol or sorafenib alone. These results lay the foundation for subsequent research on this novel therapeutic regimen in human prostate cancer.

Identification of Hyper-Methylated Tumor Suppressor Genes-Based Diagnostic Panel for Esophageal Squamous Cell Carcinoma (ESCC) in a Chinese Han Population.

DNA methylation-based biomarkers were suggested to be promising for early cancer diagnosis. However, DNA methylation-based biomarkers for esophageal squamous cell carcinoma (ESCC), especially in Chinese Han populations have not been identified and evaluated quantitatively. Candidate tumor suppressor genes (N = 65) were selected through literature searching and four public high-throughput DNA methylation microarray datasets including 136 samples totally were collected for initial confirmation. Targeted bisulfite sequencing was applied in an independent cohort of 94 pairs of ESCC and normal tissues from a Chinese Han population for eventual validation. We applied nine different classification algorithms for the prediction to evaluate to the prediction performance. ADHFE1, EOMES, SALL1 and TFPI2 were identified and validated in the ESCC samples from a Chinese Han population. All four candidate regions were validated to be significantly hyper-methylated in ESCC samples through Wilcoxon rank-sum test (ADHFE1, P = 1.7 × 10-3; EOMES, P = 2.9 × 10-9; SALL1, P = 3.9 × 10-7; TFPI2, p = 3.4 × 10-6). Logistic regression based prediction model shown a moderately ESCC classification performance (Sensitivity = 66%, Specificity = 87%, AUC = 0.81). Moreover, advanced classification method had better performances (random forest and naive Bayes). Interestingly, the diagnostic performance could be improved in non-alcohol use subgroup (AUC = 0.84). In conclusion, our data demonstrate the methylation panel of ADHFE1, EOMES, SALL1 and TFPI2 could be an effective methylation-based diagnostic assay for ESCC.

Genetic variant of miR-4293 rs12220909 is associated with susceptibility to non-small cell lung cancer in a Chinese Han population.

Non-small cell lung cancer is one of the most common cancers and the leading cause of cancer death worldwide. Genetic variants in regulatory regions of some miRNAs might be involved in non-small cell lung cancer susceptibility and survival. rs12220909 (G/C) genetic polymorphism in miR-4293 has been shown to be associated with decreased risk of esophageal squamous cell carcinoma. However, the influence of rs12220909 genetic variation on non-small cell lung cancer susceptibility has not been reported. In order to evaluate the potential association between miR-4293 rs12220909 and non-small cell lung cancer risk in a Chinese population, we performed a case-control study among 998 non-small cell lung cancer cases and 1471 controls. The data shows that miR-4293 rs12220909 was significantly associated with decreased susceptibility to non-small cell lung cancer (GC vs.GG: OR = 0.681, 95%CI = 0.555-0.835, P = 2.19E-4; GG vs. GC+CC: OR = 0.687, 95%CI = 0.564-0.837, P = 1.95E-4), which indicates that rs12220909 in miR-4293 may play a significant role in the development of non-small cell lung cancer.