The tumor-suppressive function of UNC5D and its repressed expression in renal cell carcinoma

Identification of Epigenetically Modified Hub Genes and Altered Pathways Associated With Retinoblastoma

Retinoblastoma (Rb) is the most common childhood malignancy initiated by biallelic mutation in RB1 gene and driven by various epigenetic events including DNA methylation and microRNA dysregulation. Hence, understanding the key genes that are critically modulated by epigenetic modifications in RB1 -/- cells is very important to identify prominent biomarkers and therapeutic targets of Rb. In this study, we for the first time have integrated various Rb microarray NCBI-GEO datasets including DNA Methylation (GSE57362), miRNA (GSE7072) and mRNA (GSE110811) to comprehensively investigate the epigenetic consequences of RB loss in retinoblastoma tumors and identify genes with the potential to serve as early diagnostic markers and therapeutic targets for Rb. Interestingly, the GEO2R and co-expression network analysis have identified three genes namely E2F3, ESR1, and UNC5D that are significantly deregulated by modified DNA methylation, mRNA and microRNA expression in Rb tumors. Due to their recognition in all epigenetic, transcriptomic, and miRNA datasets, we have termed these genes as "common genes". The results of our integrative bioinformatics analysis were validated in vitro by studying the gene and protein expression of these common genes in Y79, WERI-Rb-1, Rb cell lines and non-tumorigenic retinal pigment epithelial cell line (hTERT-RPE). The expression of E2F3 and UNC5D were up-regulated and that of ESR1 was down-regulated in Rb tumor cells when compared to that in non-tumorigenic hTERT-RPE cells. More importantly, UNC5D, a potent tumor suppressor gene in most cancers is significantly up-regulated in Y79 and Weri Rb1 cells, which, in turn, questions its anti-cancer properties. Together, our study shows that E2F3, ESR1, and UNC5D may be crucially involved in Rb tumorigenesis and possess the potential to act as early diagnostic biomarkers and therapeutic targets of Rb.

Promoter methylation-mediated repression of UNC5 receptors and the associated clinical significance in human colorectal cancer

Background

Deregulated methylation of tumor suppressor genes is a hallmark event in colorectal cancer (CRC) carcinogenesis. UNC5 receptors, down-regulated in various human malignancies due to epigenetic alterations, have been proposed as putative tumor suppressor genes. In this study, we focused on the methylation-mediated inhibition of UNC5 receptors and the associated clinical significance in CRC.

Methods

Methylation and expression analysis was performed in TCGA datasets. And the results were confirmed in vitro in CRC cell lines treated with 5-aza-deoxycytidine. Then, the expression and epigenetic alterations of UNC5 receptors were evaluated in clinical specimens. Moreover, the diagnostic and prognostic values of the methylation alterations were also analyzed.

Results

Methylation-mediated repression was observed in UNC5C and UNC5D, but not in UNC5A and UNC5B, which was confirmed in CRC cell lines. Except for UNC5B, significantly elevated methylation was observed in UNC5A, UNC5C, and UNC5D in CRC. The discrimination efficiency of the three receptors was comparable with that of SEPT9. Kaplan–Meier curve survival analysis showed that hypermethylation of UNC5A, UNC5C and UNC5D was associated with poor progression-free and overall survival. Moreover, methylation levels of UNC5C and UNC5D were independent predictors of CRC progression-free (P = 0.001, P = 0.003, respectively) and overall survival (P = 0.008, P = 0.004, respectively).

Conclusions

Hypermethylation of UNC5C and UNC5D mediates the repression and has promising diagnostic and prognostic values in CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01211-5.

UNC5 dependence receptor family in human cancer: A controllable double-edged sword

UNC5 receptor family (UNC5A-D) have been identified as dependence receptors whose functions depend on the availability of their ligand netrin-1. Through binding to netrin-1, these receptors transmit signals for cell survival, migration and differentiation, and participate in diverse physiological and pathological processes. In the lack of netrin-1, however, these receptors initiate apoptosis-inducing signal. Accumulating evidence reveals that netrin-1 and its receptors play a role in tumorigenesis and tumor progression. The expression of UNC5 receptor family is down-regulated in a variety of human tumors. Expression aberrance of UNC5 receptor family in tumors is caused by diverse mechanisms including genomic, epigenetic, transcriptional and post-transcriptional regulation. Notably, blocking netrin-1 binding to its receptors induces apoptotic cell death in tumor cells. In this review, we describe the characters and roles of UNC5 family members in tumorigenesis and tumor progression, discussing the regulatory mechanisms underlying down-regulation of UNC5 family members as well as recent implications of targeting netrin-1/UNC5 on potential clinical application for cancer treatment.

Exome sequencing identifies somatic mutations in novel driver genes in non-small cell lung cancer

Lung cancer is the leading cause of cancer death worldwide and accounts for more than one-third of all newly diagnosed cancer cases in China. Therefore, it is of great clinical significance to explore new driver gene mutations in non-small-cell lung cancer (NSCLC). Using an initial bioinformatic analysis, we identified somatic gene mutations in 13 patients with NSCLC and confirmed these mutations by targeted sequencing in an extended validation group of 88 patients. Recurrent mutations were detected in UNC5D (7.9%), PREX1 (5.0%), HECW1 (4.0%), DACH1 (2.0%), and GPC5 (2.0%). A functional study was also performed in UNC5D mutants. Mutations in UNC5D promoted tumorigenesis by abolishing the tumor suppressor function of the encoded protein. Additionally, in ten patients with lung squamous cell carcinoma, we identified mutations in KEAP1/NFE2L2 that influenced the expression of target genes in vivo and in vitro. Overall, the results of our study expanded the known spectrum of driver mutations involved in the pathogenesis of NSCLC.

Explore prognostic marker of colorectal cancer based on ceRNA network

Colorectal cancer (CRC) is one of the most common malignant tumors in the world. With the deepening of people's understanding of CRC at the molecular level, the survival and prognosis of CRC have been significantly improved with the help of surgery, radiotherapy, and chemotherapy, molecular targeted biological therapy and early detection of diseases. The research of different disciplines and the development of multihistological analysis in recent years have proved that the occurrence and development of CRC is a complex biological process with the common action of multiple factors, which involves the huge changes of various histological levels such as the genome, transcriptome, and epigenome. At present, the abnormal expression of protein products in the transcription process has attracted more and more attention. Based on the sensitivity and timeliness of its changes, it has become a hot topic to study the occurrence and development mechanism of CRC through transcriptome changes, so as to provide markers for early diagnosis and prognosis. In recent years, competitive endogenous RNA (ceRNA) has become one of the hot topics in cancer research. The ceRNA hypothesis holds that transcripts such as long noncoding RNA can competitively bind microRNA (miRNA), thus preventing miRNA from binding to messenger RNA (mRNA) and thereby regulating the expression of mRNA. At present, the interaction mechanism of ceRNA in CRC is still unclear, and exploring its interaction relationship is of great significance to elucidate the occurrence and development mechanism of CRC. In this study, we used The Cancer Genome Atlas (TCGA) RNA - seq data of colorectal Cancer and microRnas - seq data to construct colorectal Cancer ceRNA topology network to mine key RNAs that influence the prognosis of colorectal cancer, providing potential RNA biomarkers.

UNC5D, suppressed by promoter hypermethylation, inhibits cell metastasis by activating death-associated protein kinase 1 in prostate cancer

Prostate cancer (PCa) death primarily occurs due to metastasis of the cells, but little is known about the underlying molecular mechanisms. This study aimed to evaluate the expression of UNC5D, a newly identified tumor suppressor gene, analyze its epigenetic alterations, and elucidate its functional relevance to PCa metastasis. Meta-analysis of publicly available microarray datasets revealed that UNC5D expression was frequently downregulated in PCa tissues and inversely associated with PCa metastasis. These results were verified in clinical specimens by real-time PCR and immunohistochemistry assays. Through methylation analysis, the downregulated expression of UNC5D in PCa tissues and cell lines was found to be attributable to the hypermethylation of the promoter. A negative correlation was observed between methylation and UNC5D mRNA expression in PCa samples. The ectopic expression of UNC5D in PCa cells effectively reduced their ability to migrate and invade both in vitro and in vivo, and siRNA-mediated knockdown of UNC5D yielded consistent results. UNC5D can recruit and activate death-associated protein kinase 1, which remained to be essential for its metastatic suppressor function. In conclusion, these results suggested that UNC5D as a novel putative metastatic suppressor gene that is commonly down-regulated by hypermethylation in PCa.

Copy number changes at 8p11-12 predict adverse clinical outcome and chemo- and radiotherapy response in breast cancer

Purpose

The short arm of chromosome 8 (8p) is a frequent target of loss of heterozygosity (LOH) in cancer, and 8p LOH is commonly associated with a more aggressive tumor phenotype. The 8p11-12 region is a recurrent breakpoint area characterized by a sharp decrease in gains/amplifications and increase in allelic loss towards 8pter. However, the clustering of genomic aberrations in this region, even in the absence of proximal amplifications or distal LOH, suggests that the 8p11-12 region could play a pivotal role in oncogenesis.

Results

Loss in the FGFR1 and ZNF703-containing 8p11 region was seen in 25% of patients, correlated with lower mRNA expression levels and independently predicted poor survival, particularly in systemic treatment-naïve patients and even without adjacent 8p12 loss. Amplification of FGFR1 at 8p11 and loss of DUSP26 and UNC5D, located in the 8p12 breakpoint region, independently predicted worse event free survival. Gains in the 8p12 region encompassing WRN, NRG1, DUSP26 and UNC5D, seen in 20-30% of patients, were associated with higher mRNA expression and independently predicted chemotherapy sensitivity. Losses at 8p12 independently predicted radiotherapy resistance.

Material and methods

Multiplex ligation-dependent probe amplification was used to investigate copy number aberrations at 8p11-12 in 234 female breast cancers. Alterations were correlated with clinicopathologic characteristics, survival and response to therapy. Results were validated using public METABRIC data.

Conclusion

Allelic loss and amplification in the 8p11-12 breakpoint region predict poor survival and chemo- and radiotherapy response. Assessment of 8p11-12 gene copy number status seems to augment existing prognostic and predictive tools.

Tumor-suppressive function of UNC5D in papillary thyroid cancer

Background

Studies have shown an association of the UNC5D gene with kidney and bladder cancer and neuroblastoma. We investigated whether UNC5D acts as a tumor suppressor in papillary thyroid carcinoma (PTC).

Methods

Primary PTC tumors and matched normal thyroid tissues were obtained from 112 patients to detect UNC5D mRNA by real-time PCR. Genomic DNA sequencing was performed to detect BRAF mutation in PTC tumors. The association between UNC5D expression and clinicopathological data from PTC patients was reviewed retrospectively. PTC-derived cancer cell lines TPC-1 and K1 with stable transfection of UNC5D were used to investigate the functions of UNC5D. Flow cytometry, CCK-8, Transwell assay and scratch tests were used to examine cell cycle distribution, proliferation and migration.

Results

The expression of UNC5D was significantly decreased in PTC compared with adjacent normal thyroid tissues. Lower UNC5D expression was significantly associated with aggressive tumor behaviors, such as lymph node metastasis and BRAF mutation. Overexpression of UNC5D significantly suppressed malignant cell behaviors, including cell proliferation and migration, as well as tumor growth in vivo.

Conclusions

These findings suggest a potential tumor suppressor role of UNC5D in PTC progression; and provide insight into potential clinical relevance for the prognosis of PTC.

Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) promotes lung tumorigenesis via attenuating p53 stability

Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3/IMP3/KOC), initially identified as an RNA-binding protein, is highly expressed in embryonic tissues and a variety of cancers. Previously, our group reported that IGF2BP3 may serve as a potential diagnostic marker for lung cancer. However, little is known about the function of IGF2BP3 in lung cancer development. Here we demonstrate that IGF2BP3 expression was markedly increased in lung cancer tissues compared to normal tissues at both mRNA and protein levels. Overexpression of IGF2BP3 in lung cancer cells promoted cell proliferation, tumor migration and invasion in vitro and in vivo, whereas knockdown of IGF2BP3 exhibited opposite effects. Notably IGF2BP3 was directly associated with a deubiquitinase Ubiquitin specific peptidase 10 (USP10) and attenuated its function in stabilizing p53 protein. Silencing IGF2BP3 expression in lung cancer cells consistently increased the half-life and protein level of p53 and induced G0/G1 arrest. Thus, our data together demonstrate that IGF2BP3 promotes lung tumorigenesis via attenuating p53 protein stability.

Down-regulation of C12orf59 is associated with a poor prognosis and VHL mutations in renal cell carcinoma

C12orf59 is newly identified gene in kidney. However, the relation of C12orf59 expression and clinic features is unknown. Here, our study showed that C12orf59 was broadly expressed in normal human tissues with high expression levels in kidney while its expression is beyond detectable in a panel of cancer cell lines. C12orf59 expression in RCC was significantly decreased compared with corresponding adjacent noncancerous tissues (P < 0.01). The decreased C12orf59 expression was correlated with lymph node status (P < 0.05), distant metastases (P < 0.05), poor survival (P < 0.001) (HR 3.00; 95% CI, 1.29–7.53), VHL non-sense mutations or frame-shift mutations (P < 0.01), and UMPP gene non-sense mutations or frame-shift mutations (P = 0.01). Thus, we propose that the decreased C12orf59 expression status is a prognostic biomarker of ccRCC and cooperates with the loss of VHL all the while promoting renal carcinogenesis.

Overexpression of UNC5B in bladder cancer cells inhibits proliferation and reduces the volume of transplantation tumors in nude mice

Background

The netrin-1 receptor UNC5B plays vital roles in angiogenesis, inflammation, embryonic development and carcinogenesis. However, the functional significance of UNC5B overexpression in bladder cancer remains unclear. In this study, we investigated the role of UNC5B in bladder cancer in vitro and in vivo.

Methods

Stable transfection of the human bladder cancer cell line 5637 with UNC5B (5637-U) was confirmed by real-time RT-PCR, western blot and immunofluorescence assays. UNC5B expression in 5637 and 5637-U cells and mice tumor specimens derived from these cell lines was analyzed by immunohistochemistryand western blotting. Changes in the levels of cell cycle proteins were evaluated by western blotting. Flow cytometry, CCK-8 and scratch tests were used to examine cell cycle distribution, proliferation and migration, respectively.

Results

UNC5B overexpression in 5637 cells inhibited cell multiplication and migration and induced cell cycle arrest at the G2/M phase, meanwhile exhibited changes in the expression of cell cycle-associated proteins, showing that UNC5B may inhibit metastatic behaviors in bladder cancer cells. In addition, tumors generated from 5637-U cells were smaller than tumors generated from control 5637 cells.

Conclusions

Our findings suggest that UNC5B is a potential anti-neoplastic target in bladder cancer progression.

The phosphatase DUSP2 controls the activity of the transcription activator STAT3 and regulates TH17 differentiation

Deregulation of the TH17 subset of helper T cells is closely linked with immunological disorders and inflammatory diseases. However, the mechanism by which TH17 cells are regulated remains elusive. Here we found that the phosphatase DUSP2 (PAC1) negatively regulated the development of TH17 cells. DUSP2 was directly associated with the signal transducer and transcription activator STAT3 and attenuated its activity through dephosphorylation of STAT3 at Tyr705 and Ser727. DUSP2-deficient mice exhibited severe susceptibility to experimental colitis, with enhanced differentiation of TH17 cells and secretion of proinflammatory cytokines. In clinical patients with ulcerative colitis, DUSP2 was downregulated by DNA methylation and was not induced during T cell activation. Our data demonstrate that DUSP2 is a true STAT3 phosphatase that modulates the development of TH17 cells in the autoimmune response and inflammation.

Netrin-1: The new tumor markers in renal clear cell carcinoma

OBJECTIVE

To explore the expression of Netrin-1 protein in human renal clear cell carcinoma (RCCC) and the relationships between Netrin-1, pathology and prognosis.

METHODS

72 cases of RCCC admitted in our hospital from 2008 June to 2009 June and their adjacent tissues were selected for study. They included 30 cases in stage Ⅰ-Ⅱ, 42 cases in stage Ⅲ-Ⅳ; 9 cases in grade Ⅰ, 9 cases in grade Ⅱ, 40 cases in grade Ⅲ and 14 cases in grade Ⅳ. All cases were followed up for more than 5 years. Survival analysis lines were made by Kaplan-Meier method and the difference between groups was tested by the Log-rank test. The expression of Netrin-1 protein was detected by immunohistochemistry staining and its clinical significance was analyzed.

RESULTS

Renal clear cell carcinoma: 51 cases in high expression of Netrin-1 and 21 cases in low expression, normal tissues: 12 cases in high expression of Netrin-1 and 60 cases in low expression, the difference between the two groups is significant (χ(2) = 42.921, P ＜ 0.01). The difference of the expression of Netrin-1in Fuhrman grade and AJCC clinical stage is significant (χ(2) = 8.000, χ(2) = 6.203; P＜0.05). The 5-year survival rate in low protein expression group and in high protein expression group was 79％ (17/21) and 62％ (32/51). The survival curve had different trend, with no significant difference between groups ((χ(2) = 1.360, P = 0.245).

CONCLUSIONS

Netrin-1 protein plays an important role in the development of RCCC. It might be a new specific tumor marker of RCCC, and might become a new target in treatment of RCCC.

Overexpression of the dependence receptor UNC5H4 inhibits cell migration and invasion, and triggers apoptosis in neuroblastoma cell

UNC5H4 is a newly identified member of the UNC5H receptor family. Previously, we have demonstrated that UNC5H4 expression is significantly higher in favorable neuroblastomas than in unfavorable ones, and higher UNC5H4 level is correlated with longer survival time. However, the function of UNC5H4 in the tumorigenesis of neuroblastoma still remains elusive. In the present study, the effects of UNC5H4 overexpression on neuroblastoma SH-SY5Y cells were investigated. We showed that enforced expression of UNC5H4 receptor significantly inhibited anchorage-dependent and anchorage-independent growth of SH-SY5Y cells. Cell migration and invasion of SH-SY5Y cells transfected with UNC5H4-expressing plasmid were obviously suppressed as compared to those transfected with emptor vector or non-transfected cells. Moreover, overexpression of UNC5H4 resulted in apoptosis in SH-SY5Y cells. The induction of apoptosis by UNC5H4 was completely abolished in the presence of its ligand, netrin-1. Finally, caspase cleavage and the presence of death domain were required for UNC5H4 to induce apoptosis in neuroblastoma SH-SY5Y cells. These data suggest that the dependence receptor UNC5H4 may act as a putative tumor suppressor in neuroblastoma.

Reduced expression of Slit2 in renal cell carcinoma

Slit2, initially identified as an important axon guidance molecule in the nervous system, was suggested to be involved in multiple cellular processes. Recently, Slit2 was reported to function as a potential tumor suppressor in diverse tumors. In this study, we systematically analyzed the expression level of Slit2 in renal cell carcinoma. Compared to paired adjacent non-malignant tissues, both Slit2 mRNA and protein expression were significantly down-regulated in renal cell carcinoma (RCC). Methylation-specific PCR showed that Slit2 promoter was methylated in two renal carcinoma cell lines. Pharmacologic demethylation dramatically induced Slit2 expression in cancer cell lines with weak expression of Slit2. Besides, bisulfite genomic sequencing confirmed that dense methylation existed in Slit2 promoter. Furthermore, in paired RCC samples, Slit2 methylation was observed in 8 out of 38 patients (21.1 %), which was well correlated with the down-regulation of Slit2 in RCC. Therefore, Slit2 may also be a potential tumor suppressor in RCC, which is down-regulated in RCC partially due to promoter methylation.