Selective Retention of an Inactive Allele of the DKK2 Tumor Suppressor Gene in Hepatocellular Carcinoma

The assessment of Dickkopf-1 and Dickkopf-2 protein concentration in different subtypes of non-small cell lung cancer subtypes

Introduction

Lung cancer is one of the most prevalent cancers worldwide. Dickkopf-1 (DKK-1) and -2 (DKK-2) are important proteins for the regulated Wnt signalling pathway. Alternations in the Wnt pathway are associated with tumour progression. The aim of the study was to analyse the concentration of DKK-1 and DKK-2 in tumour and matched non-tumour (NT) samples of 65 patients with non-small cell lung cancer (NSCLC), including 3 subtypes: adenocarcinoma (AC), squamous cell carcinoma (SCC), and large cell carcinoma (LCC).

Material and methods

The protein concentration was measured by enzyme-linked immunosorbent assay (ELISA) in homogenates.

Results

The difference between the level of DKK-1 in tumour and NT specimens was not significant for the whole NSCLC group and SCC and LCC subtype, while in AC samples they were significantly higher (p = 0.028). The highest concentration of DKK-1 was found in the advanced NSCLC samples, with the T4 parameter as well as stage III. Significantly decreased DKK-2 concentrations were detected in all NSCLC subtypes (p < 0.05). Moreover, the DKK-2 level was higher in non-smokers than in smokers. The results indicate that concentrations of DKKs were different in relation to subtypes as well as clinical and socio-demographic parameters. The concentration of DKKs could be associated with the progression of NSCLC.

Conclusions

We suggest that DKK-1 could play an oncogenic role in AC, while DKK-2 could be a tumour suppressor in all NSCLC subtypes. Dickkopf-1 and DKK-2 proteins could have differential roles in the Wnt signalling pathway, which is important in many cellular processes, such as proliferation and apoptosis.

WNT/β-catenin signaling in hepatocellular carcinoma: The aberrant activation, pathogenic roles, and therapeutic opportunities

Hepatocellular carcinoma (HCC) is a liver cancer, highly heterogeneous both at the histopathological and molecular levels. It arises from hepatocytes as the result of the accumulation of numerous genomic alterations in various signaling pathways, including canonical WNT/β-catenin, AKT/mTOR, MAPK pathways as well as signaling associated with telomere maintenance, p53/cell cycle regulation, epigenetic modifiers, and oxidative stress. The role of WNT/β-catenin signaling in liver homeostasis and regeneration is well established, whereas in development and progression of HCC is extensively studied. Herein, we review recent advances in our understanding of how WNT/β-catenin signaling facilitates the HCC development, acquisition of stemness features, metastasis, and resistance to treatment. We outline genetic and epigenetic alterations that lead to activated WNT/β-catenin signaling in HCC. We discuss the pivotal roles of CTNNB1 mutations, aberrantly expressed non-coding RNAs and complexity of crosstalk between WNT/β-catenin signaling and other signaling pathways as challenging or advantageous aspects of therapy development and molecular stratification of HCC patients for treatment.

KDM1A drives hepatoblastoma progression by activating the Wnt/β-catenin pathway through inhibition of DKK3 transcription

This study is to explore the mechanism of KDM1A-regulated hepatoblastoma (HB) development. Cancerous and paracancer tissues of 30 HB patients were collected for detection of KDM1A and DKK3 expression. HuH-6 and HepG2 cells were subjected to assays of cellular activities after treatment with sh-KDM1A, sh-DKK3, and/or XAV-939 (an inhibitor of the Wnt/β-catenin pathway). Chromatin immunoprecipitation was used to determine the interaction of KDM1A with DKK3. Nude mice were injected with HuH-6 cells in which KDM1A was knocked down. KDM1A was highly expressed and DKK3 was lowly expressed in HB patients. Knockdown of KDM1A reduced the proliferative and invasive capabilities of HepG2 and HuH-6 cells and accelerated the cell apoptosis; these influences were nullified by knockdown of DKK3. KDM1A inhibited DKK3 transcription by reducing H3 methylation. XAV-939 treatment inhibited the development of HepG2 and HuH-6 cells in which KDM1A and DKK3 were both knocked down. Knockdown of KDM1A reduced the tumor mass, inactivated the Wnt/β-catenin signaling, and increased the expression of DKK3 in nude mice. KDM1A stimulates HB development by activating the Wnt/β-catenin pathway through inhibition of DKK3 transcription.

Dickkopf-2 (DKK2) as Context Dependent Factor in Patients with Esophageal Adenocarcinoma

Dickkopf-2 (DKK2) has been described as Wnt/beta-catenin pathway antagonist and its expression is mediated by micro RNA-221 (miRNA-221). So far, there is only limited data characterizing the role of DKK2 expression in esophageal cancer. A tissue micro array of 192 patients with esophageal adenocarcinoma was analyzed immunohistochemically for DKK2, miRNA-221 expression by RNA scope, and GATA6 amplification by fluorescence in-situ hybridization. The data was correlated with clinical, pathological and molecular data (TP53, HER2, c-myc, GATA6, PIK3CA, and KRAS amplifications). DKK2 expression was detectable in 21.7% and miRNA-221 expression in 33.5% of the patients. We observed no correlation between DKK2 or miRNA-221 expression and clinico-pathological data DKK2 expression was correlated with TP53 mutations and amplification of GATA6. We did not detect a survival difference in dependence of DKK2 for the total cohort, however, in patients without neoadjuvant treatment DKK2 expression correlated with a prolonged survival (median overall-survival 202 vs. 55 months, p = 0.012) which turned opposite in patients that underwent neoadjuvant treatment. High amounts of miRNA-221 were in trend associated with a prolonged overall-survival (p = 0.070). DKK2 as a Wnt antagonist is associated with prolonged survival in patients without neoadjuvant treatment and changes its prognostic value to the contrary in patients after neoadjuvant therapy. The modulatory effects of neoadjuvant treatment in connection with DKK2 expression are not fully understood, but when considering DKK2 as a tumor marker, it is necessary to see it in the context of neoadjuvant therapy.

Long non‑coding RNA TP73 antisense RNA 1 facilitates the proliferation and migration of cervical cancer cells via regulating microRNA‑607/cyclin D2

The present study aimed to explore the effect of the long non‑coding RNA TP73 antisense RNA 1 (TP73‑AS1) on cervical cancer progression. Cervical cancer and adjacent tissues were collected from 56 patients and assessed. In addition, HeLa and CaSki cells were transfected with various plasmids, inhibitors and corresponding controls, and then Cell Counting Kit‑8 and Transwell assays were used to detect the cell proliferation, migration and invasion abilities. Luciferase reporter gene assay was also performed in HeLa cells. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to investigate TP73‑AS1, microRNA‑607 (miR‑607) and cyclin D2 (CCND2) gene expression, while CCND2 protein expression was determined by western blot analysis. The results revealed that the TP73‑AS1 level was upregulated in cervical cancer tissues (P<0.05) and predicted a poor 5‑year overall survival (P<0.05). HeLa and CaSki cells transfected with siTP73‑AS1 exhibited reduced proliferation, migration and invasion abilities when compared with those in the siNC group (P<0.05). Furthermore, miR‑607 was found to be negatively regulated by TP73‑AS1, while CCND2 was negatively regulated by miR‑607. HeLa and CaSki cells transfected with siTP73‑AS1 exhibited lower CCND2 mRNA and protein expression levels compared with the siNC and siTP73‑AS1 + miR‑inhibitor groups (P<0.05). Compared with the siNC and siTP73‑AS1 + CCND2 overexpression groups, siTP73‑AS1‑transfected HeLa and CaSki cells had decreased proliferation, migration and invasion abilities (P<0.05). In conclusion, the findings suggested that upregulation of TP73‑AS1 promoted cervical cancer progression by promoting CCND2 via the suppression of miR‑607 expression.

Interplay of miRNAs and Canonical Wnt Signaling Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the leading causes of cancer death worldwide and the activation of canonical Wnt signaling pathway is universal in hepatocellular carcinoma patients. MicroRNAs are found to participate in the pathogenesis of hepatocellular carcinoma by activating or inhibiting components in the canonical Wnt signaling pathway. Meanwhile, transcriptional activation of microRNAs by canonical Wnt signaling pathway also contributes to the occurrence and progression of hepatocellular carcinoma. Pharmacological inhibition of hepatocellular carcinoma pathogenesis and other cancers by microRNAs are now in clinical trials despite the challenges of identifying efficient microRNAs candidates and safe delivery vehicles. The focus of this review is on the interplay mechanisms between microRNAs and canonical Wnt signaling pathway in hepatocellular carcinoma, and a deep understanding of the crosstalk will promote to develop a better management of this disease.

Expression of hepatic Wnt5a and its clinicopathological features in patients with hepatocellular carcinoma

BACKGROUD

Wingless-type MMTV integration site family member 5a (Wnt5a) is involved in carcinogenesis. However, little data are available in Wnt5a signaling with hepatocellular carcinoma (HCC). In the present study, we investigated the expression of hepatic Wnt5a in HCC and the role of Wnt5a in HCC progression and outcome.

METHODS

Wnt5a expression and cellular distribution in HCCs and their matched paracancerous tissues from 87 patients were analyzed with tissue microarray and immunohistochemistry and compared with hepatic Wnt3a signaling. Wnt5a expression was categorized into low or high based on immunohistochemistry. Overall survival rate of HCC patients was estimated in correlation with the hepatic Wnt5a level using Kaplan-Meier method; the survival difference between patients with low and those with high Wnt5a was compared with log-rank test; and prognostic analysis was carried out with Cox regression.

RESULTS

Total incidence of Wnt5a expression in the HCC tissues was 70.1%, which was significantly lower (χ²= 13.585, P < 0.001) than that in their paracancerous tissues (88.5%). Significant difference of Wnt5a intensity was found between HCC and their paracancerous tissues (Z = 8.463, P < 0.001). Wnt5a intensity was inversely correlated with Wnt3a signaling (r = -0.402, P < 0.001) in HCC tissues. A decrease of Wnt5a expression in relation to the clinical staging from stage I to IV and low or no staining at advanced HCC were observed. Wnt5a level was related to periportal embolus (χ²= 11.069, P < 0.001), TNM staging (χ²= 8.852, P < 0.05), 5-year survival (χ²= 4.961, P < 0.05), and confirmed as an independent prognosis factor of HCC patients (hazard ratio: 1.957; 95% confidence interval: 1.109-3.456; P < 0.05).

CONCLUSIONS

The decrease of hepatic Wnt5a signaling is associated with HCC progression and poor prognosis.