Downregulation of thrombospondin-1 by DNA hypermethylation is associated with tumor progression in laryngeal squamous cell carcinoma

MicroRNA-3907 promotes the proliferation and migration of sebaceous gland carcinoma of the eyelid by targeting thrombospondin 1

MicroRNAs (miRNAs/miRs) play an important role in various types of carcinoma, including sebaceous gland carcinoma (SGC) of the eyelid. miR-3907 was found to be highly expressed in lung cancer; however, to the best of our knowledge, the biological role of miR-3907 in SGC has not previously been evaluated. The aim of the present study was to determine the role and mechanism of miR-3907 in the occurrence and development of SGC. miR-3907 was screened and identified as a novel upregulated miRNA in SGC tissues and cells, as determined using miRNA microarrays and reverse transcription-quantitative (RT-q) PCR analyses. Compared with the control group, cellular proliferation and migration were enhanced in the miR-3907 mimics group, and decreased in the miR-3907 inhibitor group. Moreover, miR-3907 negatively regulated thrombospondin 1 (THBS1) expression, as shown by bioinformatics prediction, RT-qPCR, western blotting and dual-luciferase reporter assays. In addition, compared with the control group, the small interfering (si) siRNA-THBS1 group exhibited enhanced proliferation and migration abilities, which were decreased in the THBS1 overexpression group. Furthermore, THBS1 overexpression was found to attenuate the stimulative effect of miR-3907 mimics, and THBS1-knockdown reversed the inhibitory effect of the miR-3907 inhibitor in SGC cells. Collectively, the results of the present study indicated that miR-3907 promoted the proliferation and migration of SGC by downregulating THBS1, and that this axis may be a potential target for the prognostic assessment and treatment of SGC.

Circulating methylated THBS1 DNAs as a novel marker for predicting peritoneal dissemination in gastric cancer

Objectives

Thrombospondin 1 (THBS1) is known to play a key role in tumor metastasis, and aberrant DNA methylation is one of the mechanisms regulating THBS1. The present study investigated whether methylated THBS1 in circulating cell‐free DNA from preoperative peritoneal lavage fluid (PPLF) and peripheral blood could be used as a potential biomarker for predicting peritoneal dissemination in gastric cancer (GC) patients.

Methods

The status of THBS1 methylation was detected by quantitative methylation‐specific PCR (MSP) in tumor tissues, paired PPLF, and serum from 92 GC patients. The correlation between methylated THBS1 levels and peritoneal dissemination of GC was studied, and its diagnostic value for predicting peritoneal dissemination was clarified by the receiver operating characteristic (ROC) curve.

Results

Aberrant THBS1 methylation in tumor tissues was significantly higher than that in paracancerous normal tissues (p < 0.0001). No THBS1 methylation was found in 40 healthy controls, and partial methylation was detected in 3 of 48 patients with chronic non‐atrophic gastritis. The frequency of THBS1 methylation in pairing PPLF and serum from 92 GC patients was 52.2% (48/92) and 58.7% (54/92), respectively. The results of methylated THBS1 in pairing PPLF and serum were similar to those of tumor tissues. Aberrant THBS1 methylation in tumor tissues and pairing PPLF or serum was closely related to peritoneal dissemination, tumor progression, and poor prognosis (all p < 0.0001).

Conclusion

Circulating methylated THBS1 DNAs in PPLF/serum may predict peritoneal dissemination, a potential poor prognostic factor for GC patients.

Long non-coding RNA BZRAP1-AS1 silencing suppresses tumor angiogenesis in hepatocellular carcinoma by mediating THBS1 methylation

BACKGROUND

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer associated with a high mortality. Long non-coding RNAs (lncRNAs) have recently emerged as regulators in the development and progression of several cancers, and therefore represent an opportunity to uncover new targets for therapy. In the present study, we aimed to investigate the potential effect of lncRNA BZRAP1-AS1 on the angiogenesis of HCC.

METHODS

Microarray-based data analysis was initially employed to screen genes and lncRNAs that are differentially expressed in HCC and the candidate BZRAP1-AS1 was identified as a hit. The expression of BZRAP1-AS1 and thrombospondin-1 (THBS1) in HCC tissues and cells were then determined using RT-qPCR. The gene methylation level was measured by methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) assays. Next, the interactions between BZRAP1-AS1, DNA methyltransferase 3B (DNMT3b), and THBS1 were assessed by RIP, RNA pull-down and ChIP assays. Finally, the roles of BZRAP1-AS1, DNMT3b and THBS1 in angiogenesis in vitro as well as tumorigenesis in vivo were evaluated by a battery of the gain- and loss-of function experiments.

RESULTS

BZRAP1-AS1 was identified as a highly expressed lncRNA in HCC tissues and cells. Down-regulation of BZRAP1-AS1 in HCC cells inhibited HUVEC proliferation, migration and angiogenesis. By interacting with DNMT3b, BZRAP1-AS1 induced methylation of the THBS1 promoter and inhibited the transcription of THBS1, resulting in promoted angiogenesis of HUVECs. Moreover, silencing of BZRAP1-AS1 repressed the angiogenesis as well as the tumor growth of HCC in vivo via up-regulating THBS1.

CONCLUSION

This study provides evidence that angiogenesis in HCC is hindered by silencing of BZRAP1-AS1. Thus, BZRAP1-AS1 may be a promising marker for the treatment of HCC.

Elevated DNA methylation in malignant tumors of the sinonasal tract and its association with patient survival

BACKGROUND

Epigenetic modifications have been recognized as an important mechanism underlying carcinoma progression. DNA methylation plays an important role in cancer biology and represents potentially heritable changes in gene expression that do not involve DNA sequence. The aim of this study was to investigate promoter methylation of selected genes in sinonasal carcinoma by comparison with noncancerous sinonasal tissue.

METHODS

To search for epigenetic events (methylation in 25 tumor suppressor genes) we used MS-MLPA (Methylation-specific multiplex ligation-dependent probe amplification) to compare methylation status of 59 formalin fixed, paraffin embedded tissue samples of sinonasal carcinomas with 18 control samples. The most important changes in methylation were confirmed using MSP (Methylation specific PCR). Detected alterations in methylation were compared with clinicopathological characteristics.

RESULTS

Using a 20% cut-off for methylation (MS-MLPA), we found significantly higher methylation in GATA5 (P=0.0005), THSB1 (P=0.0002) and PAX5 (P=0.03) genes in the sinonasal cancer group compared to the control group. Methylation in five or more genes was associated with impaired overall survival (P=0.017).

CONCLUSION

These findings provide evidence that alterations in methylation profile may be one of the major mechanisms in sinonasal carcinogenesis. In addition, changes in methylation could potentially be used as prognostic factors of sinonasal carcinoma and may have implications for future individualized therapy based on epigenetic changes.

Amphotericin B-copper (II) complex alters transcriptional activity of genes encoding transforming growth factor-beta family members and related proteins in renal cells

BACKGROUND

Several chemical modifications have been developed to overcome the toxicity of amphotericin B (AmB). Oxidized forms of AmB (AmB-ox), which may occur in patient's circulation during therapy, are as toxic as AmB. Complexes with copper (II) ions (AmB-Cu²⁺) have been reported to be less toxic to human cells. Previous studies showed that AmB changed the expression of transforming growth factor-beta (TGF-β). Therefore, the objective of this study was to investigate the influence of AmB and its modified forms on the expression of genes encoding for TGF-β family members and related proteins in renal cells.

METHODS

Human renal proximal tubule cells (RPTEC) were treated with AmB-Cu²⁺, AmB, or the oxidized form AmB-ox. The expression of TGF-β family members and related genes was determined using oligonucleotide microarrays. TGF-β1 protein level was determined using ELISA method. The mRNA level of TGF-β isoforms, TGF-β receptors and differentiating genes was evaluated by real-time RT-qPCR.

RESULTS

AmB-Cu²⁺ increased the mRNA levels of TGF-β1 and TGF-β2 isoforms and two genes encoding receptors: TGFBR1 and TGFBR2. TGF-β1 protein level in culture medium was not increased after stimulation with AmB-Cu²⁺. Microarray analysis revealed changes in both pro-fibrotic and anti-fibrotic genes.

CONCLUSIONS

These results suggest that AmB-Cu²⁺ may induce repair mechanisms in renal proximal tubule cells via changes in the expression of genes involved in intracellular signaling.