Aberrant Loss of Dickkopf-3 in Gastric Cancer: Can It Predict Lymph Node Metastasis Preoperatively?

DKK3, Downregulated in Invasive Epithelial Ovarian Cancer, Is Associated with Chemoresistance and Enhanced Paclitaxel Susceptibility via Inhibition of the β-Catenin-P-Glycoprotein Signaling Pathway

Simple Summary

Dickkopf-3 (DKK3) is considered a tumor suppressor as it possesses anti-tumoral properties and is frequently downregulated in various cancers. However, the role of DKK3 in ovarian cancer is not known. In this study, we showed that DKK3 loss occurred in 56.1% of patients with ovarian cancer and that it was significantly associated with poor survival and chemoresistance. Secreted DKK3 possessed anti-tumoral properties and enhanced paclitaxel susceptibility by inhibiting the β-catenin-P-glycoprotein signaling pathway in ovarian cancer. This study revealed promising therapeutic effects of secreted DKK3, which targets paclitaxel-resistant ovarian cancer.

Abstract

Dickkopf-3 (DKK3), a tumor suppressor, is frequently downregulated in various cancers. However, the role of DKK3 in ovarian cancer has not been evaluated. This study aimed to assess aberrant DKK3 expression and its role in epithelial ovarian carcinoma. DKK3 expression was assessed using immunohistochemistry with tissue blocks from 82 patients with invasive carcinoma, and 15 normal, 19 benign, and 10 borderline tumors as controls. Survival data were analyzed using Kaplan–Meier and Cox regression analysis. Paclitaxel-resistant cells were established using TOV-21G and OV-90 cell lines. Protein expression was assessed using Western blotting and immunofluorescence analysis. Cell viability was assessed using the MT assay and 3D-spheroid assay. Cell migration was determined using a migration assay. DKK3 was significantly downregulated in invasive carcinoma compared to that in normal, benign, and borderline tumors. DKK3 loss occurred in 56.1% invasive carcinomas and was significantly associated with disease-free survival and chemoresistance in serous adenocarcinoma. DKK3 was lost in paclitaxel-resistant cells, while β-catenin and P-glycoprotein were upregulated. Exogenous secreted DKK3, incorporated by cells, enhanced anti-tumoral effect and paclitaxel susceptibility in paclitaxel-resistant cells, and reduced the levels of active β-catenin and its downstream P-glycoprotein, suggesting that DKK3 can be used as a therapeutic for targeting paclitaxel-resistant cancer.

Unsupervised learning of cross-modal mappings in multi-omics data for survival stratification of gastric cancer

Aims: This study presents a survival stratification model based on multi-omics integration using bidirectional deep neural networks (BiDNNs) in gastric cancer. Methods: Based on the survival-related representation features yielded by BiDNNs through integrating transcriptomics and epigenomics data, K-means clustering analysis was performed to cluster tumor samples into different survival subgroups. The BiDNNs-based model was validated using tenfold cross-validation and in two independent confirmation cohorts. Results: Using the BiDNNs-based survival stratification model, patients were grouped into two survival subgroups with log-rank p-value = 9.05E-05. The subgroups classification was robustly validated in tenfold cross-validation (C-index = 0.65 ± 0.02) and in two confirmation cohorts (E-GEOD-26253, C-index = 0.609; E-GEOD-62254, C-index = 0.706). Conclusion: We propose and validate a robust and stable BiDNN-based survival stratification model in gastric cancer.

Methylation Patterns of DKK1, DKK3 and GSK3β Are Accompanied with Different Expression Levels in Human Astrocytoma

In the present study, we investigated genetic and epigenetic changes and protein expression levels of negative regulators of Wnt signaling, DKK1, DKK3, and APC as well as glycogen synthase kinase 3 (GSK3β) and β-catenin in 64 human astrocytomas of grades II-IV. Methylation-specific PCR revealed promoter methylation of DKK1, DKK3, and GSK3β in 38%, 43%, and 18% of samples, respectively. Grade IV comprised the lowest number of methylated GSK3β cases and highest of DKK3. Evaluation of the immunostaining using H-score was performed for β-catenin, both total and unphosphorylated (active) forms. Additionally, active (pY216) and inactive (pS9) forms of GSK3β protein were also analyzed. Spearman's correlation confirmed the prevalence of β-catenin's active form (r_s = 0.634, p < 0.001) in astrocytoma tumor cells. The Wilcoxon test revealed that astrocytoma with higher levels of the active pGSK3β-Y216 form had lower expression levels of its inactive form (p < 0.0001, Z = -5.332). Changes in APC's exon 11 were observed in 44.44% of samples by PCR/RFLP. Astrocytomas with changes of APC had higher H-score values of total β-catenin compared to the group without genetic changes (t = -2.264, p = 0.038). Furthermore, a positive correlation between samples with methylated DKK3 promoter and the expression of active pGSK3β-Y216 (r_s = 0.356, p = 0.011) was established. Our results emphasize the importance of methylation for the regulation of Wnt signaling. Large deletions of the APC gene associated with increased β-catenin levels, together with oncogenic effects of both β-catenin and GSK3β, are clearly involved in astrocytoma evolution. Our findings contribute to a better understanding of the etiology of gliomas. Further studies should elucidate the clinical and therapeutic relevance of the observed molecular alterations.

Novel biomarkers for the diagnosis and prognosis of gallbladder cancer

Gallbladder cancer (GBC) is the most common form of biliary tract malignancy with a dismal prognosis. A poor outcome in patients with GBC is related to the aggressive nature of the tumor, delayed diagnosis, and a lack of reliable biomarkers and effective treatment. Therefore, early diagnosis and accurate disease assessment are crucial to prolonging the patient survival. Identification of novel prognostic and diagnostic biomarkers may help improve the early diagnostic rate and develop specific targeted treatments for patients with GBC. We herein review the novel biomarkers that may be associated with the diagnosis and prognosis in GBC and their potential clinical significance in the management of GBC.

Dickkopf Homolog 3 (DKK3) Acts as a Potential Tumor Suppressor in Gallbladder Cancer

Gallbladder cancer (GBC) is a common malignancy of biliary tract cancers and its incidence has been rising rapidly worldwide. The prognosis for this disease is dismal as most of the symptoms are non-specific leading to a definitive diagnosis only at a late stage. Loss of DKK3 gene is associated with a possible tumor suppressor role in human cancers. The role and regulation of DKK3 in GBC have not been studied. We found that DKK3 expression levels were low in GBC patients and cell lines. Treatment of GBC cell lines with demethylating agent 5-Aza- 2'-deoxycytidine enhances its expression, establishing impact of methylation on DKK3 expression. We observed low expression of DKK3 in gallbladder adenocarcinoma tumors and highly invasive GBC cell lines. We showed that overexpression of DKK3 can decrease cell invasion, proliferation, and colony forming ability of GBC cells. Our data thus demonstrated the DKK3 gene is a potential tumor suppressor gene in GBC and aberrant promoter methylation could be involved in its downregulation, which may play a role in the tumorigenesis and aggressiveness of GBC.

Regulatory effect of miR-346/DKK3 axis on tumor cell proliferation in colon cancer

AIM

To investigate the regulatory effect of the miR-346/DKK3 axis on tumor cell proliferation in colon cancer.

METHODS

The expression of miR-346 in normal colon epithelial cells and colon cancer cells as well as in colon tissues and noncancerous tissues was examined by RT-PCR. The effect of miR-346 on the proliferation of colon cancer cells was examined by MTT assay. Flow cytometry was used to detect the effect of miR-346 on the colon cancer cell cycle. The dual luciferase reporter gene assay was used to validate the binding relationship between miR-346 and DKK3. The effect of DKK3 on the function of colon cancer cells was studied by transfecting colon cancer cells with siRNA and pcDNA-DKK3.

RESULTS

The expression of miR-346 in colon cancer cells was significantly upregulated. Overexpression of miR-346 promoted the proliferation of colon cancer cells. The proportion of cells in G1 phase decreased, and the proportion of cells in S phase and G2/M phase increased. The dual luciferase reporter assay showed that miR-346 bound directly to the 3'-UTR of DKK3. Inhibition of DKK3 using siRNA promoted the proliferation of colon cancer cells, reduced the proportion of cells in G1 phase and increased the proportion of cells in S phase and G2/M phase. Further, overexpression of DKK3 partially abrogated the proliferative effect of miR-346 on colon cancer cells.

CONCLUSION

MiR-346 promotes the proliferation of colon cancer cells by inhibiting DKK3.

Dickkopf homolog 3 (DKK3): A candidate for detection and treatment of cancers?

Wnt signaling is an evolutionary highly conserved pathway that is modulated by several inhibitors and activators, and plays a key role in numerous physiological processes. One of the extracellular Wnt inhibitors is the DKK (Dickkopf Homolog) family which has four members (Dkk1-4) and a unique Dkk3-related gene, Dkkl1 (soggy). DKK3 is a divergent member of the DKK protein family. Evidence suggests that DKK3 may serve as a potential therapeutic target in several types of human cancers. We review here the biological role of DKK3 as a tumor suppressor gene (TSG) or oncogene, and its correlation with various miRNAs. In addition, we discuss the role of polymorphisms and promoter methylation of the DKK3 gene, and of its expression in regulating cancer cell proliferation. Finally, we propose that DKK3 may be considered as both a biomarker and a therapeutic target in different cancers.

Serum biomarker analysis in patients with recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) occurs in 1–5% of parturients. The sustained therapy and research for RSA is expensive, which is a serious issue faced by both patients and doctors. The aim of the present study was to detect protein expression profiles in the serum of RSA patients and healthy controls, and to identify potential biomarkers for this disease. A 1,000-protein microarray consisting of a combination of Human L-507 and L-493 was used. The microarray data revealed that eight serum protein expression levels were significantly upregulated and 143 proteins were downregulated in RSA patients compared with the healthy controls. ELISA individually validated 5 of these 151 proteins in a larger cohort of patients and control samples, demonstrating a significant decrease in insulin-like growth factor-binding protein-related protein 1 (IFGBP-rp1)/IGFBP-7, Dickkopf-related protein 3 (Dkk3), receptor for advanced glycation end products (RAGE) and angiopoietin-2 levels in patients with RSA. Sensitivity and specificity analyses were calculated by a receiver operating characteristics curve, and were revealed to be 0.881, 0.823, 0.79 and 0.814, with diagnostic cut-off points of 95.44 ng/ml for IFGBP-rp1, 32.84 ng/ml for Dkk3, 147.27 ng/ml for RAGE and 441.40 ng/ml for angiopoietin-2. The present study indicated that these four proteins were downregulated in RSA samples and may be useful as biomarkers for the prediction and diagnosis of RSA. Subsequent studies in larger-scale cohorts are required to further validate the diagnostic value of these markers.