Prognostic and therapeutic impact of the chromosome 20q13.2 ZNF217 locus amplification in ovarian clear cell carcinoma

BACKGROUND:

The goal of this study was to examine the clinical significance of ZNF217 amplification and assess whether ZNF217 could be a potential therapeutic target in ovarian clear cell carcinoma (OCCC).

METHODS:

ZNF217 expression and amplification in OCCC was assessed by immunohistochemistry, fluorescence in situ hybridization, and clinical data collected via a retrospective chart review. ZNF217 gene knockdown using silencing RNA (siRNA) was used to assess ZNF217 functions in OCCC cell lines.

RESULTS:

Gene amplification was identified in 12 of 60 (20.0%) OCCCs. ZNF217 copy number correlated significantly with ZNF217 protein expression (r = 0.341; P<.01). ZNF217 amplification correlated significantly with shorter progression‐free (P = .0042) and overall (P = .0199) survival. There were nonsignificant trends between high ZNF217 protein expression and poor progression‐free (P = .2594) and overall (P = .2199) survival. Multivariate analysis revealed ZNF217 gene amplification to be an independent prognostic factor for progression‐free and overall survival after standard platinum agent‐based chemotherapy (P = .0339 and P = .031, respectively). Profound growth inhibition and apoptosis were observed in ZNF217 siRNA‐treated cancer cells with gene amplification compared with cancer cells with ZNF217 moderate expression without ZNF217 gene amplification or with low ZNF217 expression.

CONCLUSION:

These findings indicate that ZNF217 overexpression is critical to growth and survival of OCCCs with ZNF217 gene amplification. Furthermore, they suggest that ZNF217 siRNA‐induced phenotypes depend on amplification status of OCCCs. Therefore, ZNF217‐targeted therapy may benefit OCCC patients with ZNF217 amplification. Cancer 2011. © 2011 American Cancer Society.     

ZNF217 is a marker of poor prognosis in breast cancer that drives epithelial-mesenchymal transition and invasion

The Krüppel-like zinc finger protein ZNF217 is a candidate oncogene in breast cancer. In this study, we showed that high levels of expression of ZNF217 mRNA are associated with poor prognosis and the development of metastases in breast cancer. Overexpression of ZNF217 in breast cancer cells stimulated migration and invasion in vitro and promoted the development of spontaneous lung or node metastases in mice in vivo. ZNF217 also promoted epithelial-mesenchymal transition (EMT) in human mammary epithelial cells, and the TGF-β-activated Smad signaling pathway was identified as a major driver of ZNF217-induced EMT. In addition, a TGF-β autocrine loop sustained activation of the TGF-β pathway in ZNF217-overexpressing mammary epithelial cells, most likely because of ZNF217-mediated direct upregulation of TGFB2 or TGFB3. Inhibition of the TGF-β pathway led to the reversal of ZNF217-mediated EMT. Together, our findings indicate that ZNF217 mRNA expression may represent a novel prognostic biomarker in breast cancer. Therapeutic targeting of ZNF217 of the TGF-β signaling pathway may benefit the subset of patients whose tumors express high levels of ZNF217.     

Silencing of ZNF217 gene influences the biological behavior of a human ovarian cancer cell line

Zinc-finger protein 217 (ZNF217), a candidate oncogene on 20q13.2, can lead cultured human ovarian and mammary epithelial cells to immortalization, which indicates selective expression of ZNF217 affecting 20q13 amplification during critical early stages of cancer progression. In this study, we tested the hypothesis that ZNF217 is a key factor in regulating ovarian cancer proliferation and progression. We examined the effect of the inhibition of ZNF217 expression on proliferation and invasion by establishing the ZNF217 knockdown ovarian cancer cell line using RNA interference (RNAi). Our results showed that silencing of ZNF217 resulted in the effective inhibition of ovarian cancer cell growth and invasive ability. The results suggested that ZNF217 might play a crucial role in the proliferation and invasion of ovarian cancer.     

ZNF217 confers resistance to the pro-apoptotic signals of paclitaxel and aberrant expression of Aurora-A in breast cancer cells

Background  

ZNF217 is a candidate oncogene located at 20q13, a chromosomal region frequently amplified in breast cancers. The precise mechanisms involved in ZNF217 pro-survival function are currently unknown, and utmost importance is given to deciphering the role of ZNF217 in cancer therapy response.     

ZNF217 is Overexpressed and Enhances Cell Migration and Invasion in Colorectal Carcinoma

Background: To investigate the expression and clinical significance of zinc finger protein 217 (ZNF217)in human colorectal carcinoma (CRC). Materials and Methods: The expression of ZNF217 in 60 CRCtissues and matched tumor adjacent tissues, collected between January 2013 and June 2014, was assessedimmunohistochemically. The relationship between the expression of ZNF217 and clinicopathlogical features wasanalyzed by Pearson chi-square test. In addition, siRNA was used to down-regulate the expression of ZNF217 inCRC cells. The effects of ZNF217 for cell migration and invasion were measured by wound healing assay andtranswell assay, respectively. Results: The expression level of ZNF217 was significantly higher in CRC tissuesthan in tumor adjacent tissues (p<0.05), positively correlating with tumor size, lymphatic metastasis and advancedTNM stage (p<0.05). Down-regulation of ZNF217 in CRC cells could significantly suppress cell migration andinvasion. Conclusions: ZNF217 is overexpressed in colorectal carcinoma tissues and is associated with tumormalignant clinicopathological features. ZNF217 may promote CRC progression by inducing cell migration andinvasion.     

DNA methylation transcriptionally regulates the putative tumor cell growth suppressor ZNF677 in non-small cell lung cancers

In our study, we investigated the role of ZNF677 in non-small cell lung cancers (NSCLC). By comparing ZNF677 expression in primary tumor (TU) and in the majority of cases also of corresponding non-malignant lung tissue (NL) samples from > 1,000 NSCLC patients, we found tumor-specific downregulation of ZNF677 expression (adjusted p-values < 0.001). We identified methylation as main mechanism for ZNF677 downregulation in NSCLC cells and we observed tumor-specific ZNF677 methylation in NSCLC patients (p < 0.0001). In the majority of TUs, ZNF677 methylation was associated with loss of ZNF677 expression. Moreover, ZNF677 overexpression in NSCLC cells was associated with reduced cell proliferation and cell migration. ZNF677 was identified to regulate expression of many genes mainly involved in growth hormone regulation and interferon signalling. Finally, patients with ZNF677 methylated TUs had a shorter overall survival compared to patients with ZNF677 not methylated TUs (p = 0.013). Overall, our results demonstrate that ZNF677 is trancriptionally regulated by methylation in NSCLCs, suggest that ZNF677 has tumor cell growth suppressing properties in NSCLCs and that ZNF677 methylation might serve as prognostic parameter in these patients.     

Mutational mechanisms of amplifications revealed by analysis of clustered rearrangements in breast cancers

BackgroundComplex clusters of rearrangements are a challenge in interpretation of cancer genomes. Some clusters of rearrangements demarcate clear amplifications of driver oncogenes but others are less well understood. A detailed analysis of rearrangements within these complex clusters could reveal new insights into selection and underlying mutational mechanisms.Patients and methodsHere, we systematically investigate rearrangements that are densely clustered in individual tumours in a cohort of 560 breast cancers. Applying an agnostic approach, we identify 21 hotspots where clustered rearrangements recur across cancers.ResultsSome hotspots coincide with known oncogene loci includingCCND1, ERBB2, ZNF217, chr8:ZNF703/FGFR1, IGF1R, andMYC. Others contain cancer genes not typically associated with breast cancer:MCL1,PTP4A1, andMYB. Intriguingly, we identify clustered rearrangements that physically connect distant hotspots. In particular, we observe simultaneous amplification ofchr8:ZNF703/FGFR1 andchr11:CCND1 where deep analysis reveals that a chr8–chr11 translocation is likely to be an early, critical, initiating event.ConclusionsWe present an overview of complex rearrangements in breast cancer, highlighting a potential new way for detecting drivers and revealing novel mechanistic insights into the formation of two common amplicons.     

The ZNF217 gene amplified in breast cancers promotes immortalization of human mammary epithelial cells

The functional consequences of overexpression of a candidate oncogene on chromosome 20q13.2, ZNF217, were examined by transducing the gene into finite life span human mammary epithelial cells (HMECs). In four independent experiments, ZNF217-transduced cultures gave rise to immortalized cells. HMECs that overcame senescence initially exhibited heterogeneous growth and continued telomere erosion, followed by increasing telomerase activity, stabilization of telomere length, and resistance to transforming growth factor beta growth inhibition. The incremental changes in telomerase activity and growth that occurred in ZNF217-transduced cultures after they overcame senescence were similar to the conversion pattern we have described previously in rare HMEC lines immortalized after exposure to a chemical carcinogen. Aberrant expression of ZNF217 may be selected for during breast cancer progression because it allows breast cells to overcome senescence and attain immortality.     

Automated analysis of protein expression and gene amplification within the same cells of paraffin-embedded tumour tissue

Background

The simultaneous detection of protein expression and gene copy number changes in patient samples, like paraffin-embedded tissue sections, is challenging since the procedures of immunohistochemistry (IHC) and Fluorescence in situ Hybridization (FISH) negatively influence each other which often results in suboptimal staining. Therefore, we developed a novel automated algorithm based on relocation which allows subsequent detection of protein content and gene copy number changes within the same cell.

Methods

Paraffin-embedded tissue sections of colorectal cancers were stained for CD133 expression. IHC images were acquired and image coordinates recorded. Slides were subsequently hybridized with fluorescently labeled DNA probes. FISH images were taken at the previously recorded positions allowing for direct comparison of protein expression and gene copy number signals within the same cells/tissue areas. Relocation, acquisition of the IHC and FISH images, and enumeration of FISH signals in the immunophenotyped tumour areas were done in an automated fashion.

Results

Automated FISH analysis was performed on 13 different colon cancer samples that had been stained for CD133; each sample was scored for MYC, ZNF217 and Chromosome 6 in CD133 positive and negative glands. From the 13 cases four (31%) showed amplification for the MYC oncogene and seven of 13 (54%) cases were amplified for ZNF217. There was no significant difference between CD133 positive tumour and CD133 negative tumour cells.

Conclusion

The technique and algorithm presented here enables an easy and reproducible combination of IHC and FISH based on a novel automated algorithm using relocation and automated spot counting.     

Coexistence of copy number increases of ZNF217 and CYP24A1 in colorectal cancers in a Chinese population

Evidence suggests that the amplification of chromosome 20q13 is common in colorectal cancers (CRCs). Certain candidate oncogenes located in this region are reported to be associated with tumorigenesis of the gastrointestinal tract. The functional impact of such regions should be extensively investigated in a large number of clinical samples. In this study, 145 CRC samples with matched adjacent normal tissues were collected from a Chinese population for copy number variation (CNV) analysis. Our results showed that both the copy numbers of 25-hydroxy vitamin D3 24-hydroxylase (CYP24A1) and zinc-finger protein 217 (ZNF217) were amplified in a relatively high percentage of CRC samples (51.1 and 60%, respectively). The mRNA expression levels of both CYP24A1 and ZNF217 were found to have increased in the collected CRC samples as compared to the matched adjacent normal tissues. ZNF217, but not CYP24A1, showed a positive correlation between copy number increases and mRNA overexpression. These findings suggest the potential role of CNVs of certain oncogenes in CRCs.