Otud6b induces pulmonary arterial hypertension by mediating the Calpain-1/HIF-1α signaling pathway.

Pulmonary hypertension (PAH) is a cardiopulmonary disease in which pulmonary artery pressure continues to rise, leading to right heart failure and death. Otud6b is a member of the ubiquitin family and is involved in cell proliferation, apoptosis and inflammation. The aim of this study was to understand the role and mechanism of Otud6b in PAH. C57BL/6 and Calpain-1 knockout (KO) mice were exposed to a PAH model induced by 10% oxygen. Human pulmonary artery endothelial cells (HPACEs) and human pulmonary artery smooth muscle cells (HPASMCs) were exposed to 3% oxygen to establish an in vitro model. Proteomics was used to determine the role of Otud6b and its relationship to Calpain-1/HIF-1α signaling. The increased expression of Otud6b is associated with the progression of PAH. ROtud6b activates Otud6b, induces HIF-1α activation, increases the production of ET-1 and VEGF, and further aggravates endothelial injury. Reducing Otud6b expression by tracheal infusion of siOtud6b has the opposite effect, improving hemodynamic and cardiac response to PAH, reducing the release of Calpain-1 and HIF-1α, and eliminating the pro-inflammatory and apoptotic effects of Otud6b. At the same time, we also found that blocking Calpain-1 reduced the effect of Otud6b on HIF-1α, and inhibiting HIF-1α reduced the expression of Calpain-1 and Otud6b. Our study shows that increased Otud6b expression during hypoxia promotes the development of PAH models through a positive feedback loop between HIF-1α and Calpain-1. Therefore, we use Otud6b as a biomarker of PAH severity, and regulating Otud6b expression may be an effective target for the treatment of PAH.

Biallelic OTUD6B variants associated with a Kabuki syndrome-like disorder in three siblings: A clinical report and literature review.

Biallelic variants in the OTUD6B gene have been reported in the literature in association with an intellectual developmental disorder featuring dysmorphic facies, seizures, and distal limb abnormalities. Physical differences described for affected individuals suggest that the disorder may be clinically recognizable, but previous publications have reported an initial clinical suspicion for Kabuki syndrome (KS) in some affected individuals. Here, we report on three siblings with biallelic variants in OTUD6B co-segregating with neurodevelopmental delay, shared physical differences, and other clinical findings similar to those of previously reported individuals. However, clinical manifestations such as long palpebral fissures, prominent and cupped ears, developmental delay, growth deficiency, persistent fetal fingertip pads, vertebral anomaly, and seizures in the proband were initially suggestive of KS. In addition, previously unreported clinical manifestations such as delayed eruption of primary dentition, soft doughy skin with reduced sweating, and mirror movements present in our patients suggest an expansion of the phenotype, and we perform a literature review to update on current information related to OTUD6B and human gene-disease association.

OTUD6B promotes cholangiocarcinoma growth by regulating STAT3 phosphorylation through deubiquitination of PTK2.

Cholangiocarcinoma (CCA) is a hepatobiliary carcinoma with uncontrolled cell proliferation, poor prognosis, and high mortality. The ovarian tumor structural domain (OTU) containing protein 6B (OTUD6B) belongs to the OTU deubiquitin family and is vital in tumor development. However, its expression and biological function in CCA remain unknown. The expression of OTUD6B in CCA was analyzed using TIMER2.0, UALCAN, and GEO databases. MTT, clonal formation assay, immunofluorescence staining, immunohistochemistry staining, and flow cytometry examined the regulation of OTUD6B on cell proliferation, cycle, and apoptosis. The effects of OTUD6B on tumor volume and weight were assessed using the xenograft tumor model. The activities of PTK2 and STAT3 were detected by western blot and CO-IP. The biological database identified that OTUD6B was upregulated in CCA. In CCA cells, OTUD6B knockdown reduced CCA cell proliferation and promoted apoptosis. Cell cycle analysis indicated that the cycle stopped at the G0/G1 phase after OTU6B downregulation. Furthermore, OTUD6B knockdown resulted in a decrease in tumor volume and weight in xenograft tumor models. Mechanistically, OTUD6B is involved in the deubiquitination of PTK2. PTK2 further affected the phosphorylation of STAT3 thereby regulating the CCA process. Our study demonstrates that OTUD6B knockdown participates in the ubiquitination of PTK2 and phosphorylation of STAT3 to alleviate the process of CCA. These results suggest that OTUD6B may be a potential new strategy for CCA treatment.

MCTS1 enhances the proliferation of laryngeal squamous cell carcinoma via promoting OTUD6B-1 mediated LIN28B deubiquitination.

The aberrant upregulation of MCTS1 Re-Initiation and Release Factor (also known as Malignant T-cell-amplified sequence 1, MCTS1) can promote laryngeal squamous cell carcinoma (LSCC). It might act as a binding partner of multiple proteins. In this study, we further explored the expression of potential interaction between MCTS1 and OTU domain-containing protein 6B (OTUD6B) and its influence on the ubiquitination and degradation of OTUD6B's substrate in LSCC. LSCC cell lines AMC-HN-8 and TU177 were utilized for assessing protein-protein interaction, protein degradation and tumor growth in vitro and in vivo. The results showed that MCTS1 interacts with OUTD6B isoform 1 (OTUD6B-1) in the cell lines. Higher OTUD6B-1 expression is associated with significantly shorter progression-free interval in LSCC patients. OTUD6B positively modulated the expression of cyclin D1, cyclin E1 and c-Myc and LSCC cell proliferation in vitro and in vivo. MCTS1 negatively modulated the degradation of LIN28B in G1/S cells, via enhancing OTUD6B-mediated cleaving of K48-branched ubiquitin chains from LIN28B. OTUD6B or LIN28B shRNA weakened MCTS1 overexpression-induced cyclin D1 and c-Myc protein expression and LSCC cell proliferation. In summary, this study revealed that MCTS1 could enhance LSCC proliferation partially via the OTUD6B-LIN28B axis.

The long noncoding RNA OTUD6B-AS1 enhances cell proliferation and the invasion of hepatocellular carcinoma cells through modulating GSKIP/Wnt/ß-catenin signalling via the sequestration of miR-664b-3p.

Ovarian tumour domain containing 6B antisense RNA1 (OTUD6B-AS1), a newly identified long noncoding RNA (lncRNA), has been reported as a key cancer-related lncRNA. However, the detailed relevance of OTUD6B-AS1 in hepatocellular carcinoma (HCC) remains undetermined. This study was designed to determine the functional significance and regulatory mechanism of OTUD6B-AS1 in HCC. We found that the expression of OTUD6B-AS1 was up-regulated in HCC tissues, and patients with high levels of OTUD6B-AS1 expression had shorter survival rates than those with low OTUD6B-AS1 expression. Elevated expression of the lncRNA was also found in multiple HCC cell lines and the silencing of OTUD6B-AS1 significantly decreased proliferation, colony formation and invasion. Correspondingly, OTUD6B-AS1 overexpression had the opposite effect on HCC cell invasion, colony formation and proliferation. Notably, OTUD6B-AS1 was identified as a molecular sponge of microRNA-664b-3p (miR-664b-3p). The down-regulation of miR-664b-3p was detected in HCC tissues and cell lines, and the up-regulation of miR-664b-3p repressed proliferation and invasion in HCC cells by targeting the glycogen synthase kinase-3ß interaction protein (GSKIP). Moreover, OTUD6B-AS1 knockdown or miR-664b-3p up-regulation exerted a suppressive effect on Wnt/ß-catenin signalling via the down-regulation of GSKIP. In addition, GSKIP overexpression markedly reversed OTUD6B-AS1 knockdown- or miR-664b-3p overexpression-induced antitumour effects in HCC. Further data confirmed that OTUD6B-AS1 knockdown exerted a tumour-inhibition role in HCC in vivo. Overall, these findings indicate that the lncRNA OTUD6B-AS1 accelerates the proliferation and invasion of HCC cells by enhancing GSKIP/Wnt/ß-catenin signalling via the sequestration of miR-664b-3p. Our study reveals a novel molecular mechanism, mediated by lncRNA OTUD6B-AS1, which may play a key role in regulating the progression of HCC.

Novel long noncoding RNA OTUD6B-AS1 indicates poor prognosis and inhibits clear cell renal cell carcinoma proliferation via the Wnt/ß-catenin signaling pathway.

BACKGROUND: The long noncoding RNA (lncRNA) OTUD6B antisense RNA 1 (OTUD6B-AS1) is oriented in an antisense direction to the protein-coding gene OTUD6B on the opposite DNA strand. TCGA database data show that the expression of the lncRNA OTUD6B-AS1 is downregulated and that OTUD6B-AS1 acts as an antioncogene in a variety of tumors. However, the expression and biological functions of the lncRNA OTUD6B-AS1 are still unknown in tumors, including clear cell renal cell carcinoma (ccRCC). METHODS: The expression level of OTUD6B-AS1 was measured in 75 paired human ccRCC tissue and corresponding adjacent normal renal tissue samples. The correlations between the OTUD6B-AS1 expression level and clinicopathological features were evaluated using the chi-square test. The effects of OTUD6B-AS1 on ccRCC cells were determined via MTT assay, clone formation assay, transwell assay, and flow cytometry. Furthermore, the impact of OTUD6B-AS1 overexpression on the activation of the Wnt/ß-catenin signaling pathway was investigated. Finally, ACHN cells with OTUD6B-AS1 overexpression were subcutaneously injected into nude mice to evaluate the influence of OTUD6B-AS1 on tumor growth in vivo. RESULTS: In this study, we found that the expression of the lncRNA OTUD6B-AS1 was downregulated in ccRCC tissue samples and that patients with low OTUD6B-AS1 expression had shorter overall survival than patients with high OTUD6B-AS1 expression, which showed that the different expression level of OTUD6B-AS1 indirectly correlated with survival of patients. Lentivirus-mediated OTUD6B-AS1 overexpression significantly decreased the proliferation of ccRCC cells and promoted the apoptosis of the cells. Furthermore, OTUD6B-AS1 overexpression partly inhibited cell migration and invasion. The overexpression of OTUD6B-AS1 decreased the activity of the Wnt/ß-catenin pathway and suppressed the expression of epithelial-to-mesenchymal transition (EMT)-related proteins (E-cadherin, N-cadherin and Snail) in ccRCC cells. In addition, compared with the parental ACHN cells, OTUD6B-AS1-overexpressing ACHN cells injected into nude mice exhibited decreased tumor growth in vivo. CONCLUSIONS: Taken together, our findings present a road map for targeting the newly identified lncRNA OTUD6B-AS1 to suppress ccRCC progression in cell lines, and these results elucidate a novel potential therapeutic target for ccRCC treatment.

The deubiquitinating protein OTUD6B promotes lung adenocarcinoma progression by stabilizing RIPK1.

BACKGROUND: There is growing evidence indicating that deubiquitinating enzymes may contribute to tumor progression and can serve as promising therapeutic targets. METHODS: The overexpression of deubiquitinase OTUD6B in lung adenocarcinoma (LUAD) and its adjacent tissues was analyzed by immunohistochemistry and TCGA/GO database. Survival analysis further supported OTUD6B as a potential target for LUAD treatment. We assessed the effect of OTUD6B on LUAD cell growth using cell viability assays and conducted TUNEL staining, migration, and invasion experiments to investigate the impact of OTUD6B on the apoptosis and metastasis of LUAD cells. Additionally, we established a transplanted tumor model in nude mice to validate our findings in vivo. Finally, using IP mass spectrometry and co-IP experiments, we screened and confirmed the influence of RIPK1 as a substrate of OTUD6B in LUAD. RESULTS: OTUD6B is highly overexpressed in human LUAD and predicts poor prognosis in LUAD patients. OTUD6B knockdown inhibited the proliferation of LUAD cells and enhanced apoptosis and inhibited metastasis in LUAD cells suppressed. A549 xenografts revealed that OTUD6B deletion can slow down tumour growth. Additionally, OTUD6B can bind to RIPK1, reduce its ubiquitination level and increase its protein stability. CONCLUSIONS: Our results suggest that OTUD6B is a promising clinical target for LUAD treatment and that targeting OTUD6B may constitute an effective anti-LUAD strategy.

Human OTUD6B positively regulates type I IFN antiviral innate immune responses by deubiquitinating and stabilizing IRF3.

IMPORTANCE: Interferon (IFN) regulatory factor (IRF3) is one of the key factors for type I IFN transcription. To sophisticatedly regulate type I IFN antiviral immune response, IRF3 activity is closely controlled by a variety of post-translational modifications. However, the regulatory mechanisms are still not fully elucidated. In the present study, we found that human deubiquitinase OTUD6B positively regulates IRF3-mediated antiviral immune response. OTUD6B can stabilize the IRF3 protein level via hydrolyzing (Lys33)-linked polyubiquitin at Lys315. More importantly, mice with OTUD6B overexpression exhibited more resistance to RNA virus infection. Thus, unlike the previous report that zebrafish OTUD6B negatively regulates the antiviral response by suppressing K63-linked ubiquitination of IRF3 and IRF7, we demonstrate that human OTUD6B actually enhances type I IFN response and has the potential for antiviral therapy.

LncRNA OTUD6B-AS1 overexpression promoted GPX4-mediated ferroptosis to suppress radioresistance in colorectal cancer.

BACKGROUND: Radiotherapy is widely employed in colorectal cancer (CRC) treatment but is often compromised by developed radioresistance. This study explored the mechanism of long non-coding RNA ovarian tumor domain containing 6B-antisense RNA1 (lncRNA OTUD6B-AS1) in CRC radioresistance through tripartite motif 16 (TRIM16). METHODS: CRC and non-cancerous tissues were collected and radioresistant CRC cells were established, with real-time quantitative polymerase chain reaction to determine gene expression in tissues and cells. Radioresistance was evaluated by cell counting kit-8 assay and immunofluorescence (γ-H2AX) and ferroptosis was tested by Western blot assay (ACSL4/GPX4) and assay kits (Fe2+/ROS/MDA/GSH). The association between ferroptosis and lncRNA OTUD6B-AS1-inhibited radioresistance was testified using ferroptosis inhibitor. The subcellular localization of lncRNA OTUD6B-AS1 was tested by the nuclear/cytoplasmic fractionation assay, with RNA immunoprecipitation assay to validate gene interactions. Rescue experiments were conducted to analyze the role of TRIM16 in CRC radioresistance. RESULTS: LncRNA OTUD6B-AS1 and TRIM16 were poorly expressed (P < 0.01) in CRC tissues and cells and further decreased (P < 0.01) in radioresistant CRC cells. OTUD6B-AS1 overexpression decreased cell survival (P < 0.01), increased γ-H2AX levels (P < 0.01), and elevated ferroptosis and oxidative stress (P < 0.01) after X-ray radiation. Ferroptosis inhibitor attenuated radioresistance (P < 0.01) caused by lncRNA OTUD6B-AS1 overexpression. LncRNA OTUD6B-AS1 stabilized TRIM16 mRNA via binding to HuR. TRIM16 knockdown reduced ferroptosis and increased radioresistance (P < 0.05). CONCLUSION: OTUD6B-AS1 overexpression stabilized TRIM16 via binding to HuR and increased GPX4-mediated ferroptosis, thus attenuating CRC radioresistance. Our study provided a new rationale for the treatment of CRC.

Loss of OTUD6B Stimulates Angiogenesis and Promotes Diabetic Atherosclerosis.

Purpose: Angiogenesis is an essential promoter of atherosclerotic plaque rupture. However, the mechanism of its regulation is not understood. OTUD6B regulates cell proliferation, migration, and angiogenesis. We investigated the role of OTUD6B in angiogenesis in diabetic atherosclerotic plaques. Patients and Methods: The expression of OTUD6B was analyzed by single cell RNA sequencing (scRNA-seq) and RNA sequencing (RNA-seq) and evaluated by Immunofluorescence in human anterior tibial arteries from diabetic amputees and ApoE-/- mice. Furthermore, we constructed a mouce model of diabetic atherosclerosis and used the mice to study the effect of OTUD6B downregulation in vivo by injecting them with AAV-shOTUD6B. Mouse brain microvascular endothelial cells (MBVECs) were treated with normal glucose and high lipid (NG/HL) or high glucose and high lipid (HG/HL), and siOTUD6B was used to investigate the effect of OTUD6B on proliferation, migration, and lumen formation of endothelial cells. Results: We found that OTUD6B expression was markedly downregulated in human anterior tibial arteries from diabetic amputees and ApoE-/- mice. The silencing of OTUD6B resulted in diabetic atherosclerotic mice plaque instability and increased angiogenesis. In addition, the silencing of OTUD6B expression enhanced the proliferation, migration, and lumen formation of endothelial cells. Conclusion: OTUD6B can reduce angiogenesis in atherosclerotic plaques, enhance plaque stability and delay the progression of atherosclerosis by regulating the proliferation, migration, and lumen formation of endothelial cells.

Identification of OTUD6B as a new biomarker for prognosis and immunotherapy by pan-cancer analysis.

Background: Ovarian-tumor (OTU) domain-containing protein 6B (OTUD6B), one of newly identified OTU deubiquitylating enzyme families, is proved to be associated with tumor progression. However, whether it plays a key role in pan-cancer still remains unknown. Methods: The profiles of OTUD6B expression in multiple cancers were analyzed using The Cancer Genome Atlas (TCGA) database. Information of protein expression was performed based on the HPA, GeneCards, and String databases. K-M plotter and survival data analysis were used to analyze the prognostic value of OTUD6B expression, including overall survival (OS), disease-specific survival (DSS), disease-free interval (DFI), and progression-free interval (PFI). R package "clusterProfiler" was used for enrichment analysis of OTUD6B. Furthermore, we analyzed the correlation between the expression of OTUD6B, immune infiltration, and immune-related genes. Additionally, we preliminarily validated its tumorigenic effect in lung cancer cell lines. Findings: OTUD6B expression was upregulated in most cancers, such as COAD, CHOL, and LUAD, and predicted poor prognosis in most cancers in TCGA. Results showed that OTUD6B expression was positively correlated with memory CD4+ T cells, Th1 CD4+ T cells, and CD8+ T cells. In terms of the immune-related genes, OTUD6B was found to be associated with most types of genes, such as immunostimulatory genes KDR, TGFBR1, and IL-10. Moreover, for most types of tumors, the immune score was found to be negatively correlated with OTUD6B expression. In addition, lung cancer cell lines with OTUD6B knockdown significantly inhibited proliferation and invasion ability of lung cancer cells. Conclusions: The study indicated that OTUD6B is an oncogene and may serve as a new potential biomarker in various tumors. OTUD6B may play a part in TIME, which could be applied as a new target for cancer therapy.

Novel biallelic variants affecting the OTU domain of the gene OTUD6B associate with severe intellectual disability syndrome and molecular dynamics simulations.

Intellectual developmental disorder with dysmorphic facies, seizures, and distal limb anomalies (IDDFSDA) is an autosomal recessive multisystem disorder caused by compound heterozygous or homozygous variants in the gene OTUD6B. Herein, we describe novel pathogenic compound heterozygous variants in OTUD6B identified via whole-exome sequencing in an index case exhibited the severe IDDFSDA phenotype. The potential pathogenicity of the novel frameshift and missense variants in the index case was investigated using in silico tools. The truncating frameshift variant in one allele was predicted to undergo degradation via nonsense-mediated decay of the mRNA molecule. To predict the severity of the damage to the protein caused by the missense variant in the other allele and its effects on phenotypic severity was further investigated together with a previously reported first homozygous missense variant in the same domain in another patient with a less severe IDDFSDA phenotype using structural modeling and molecular dynamics (MD) simulations for the first time. Based on these analyzes, it is anticipated that Tyr216Cys in the earlier reported case with less severe IDDFSDA will lead to localized destabilization, whereas Ile274Arg in the presented index case with the severe IDDFSDA phenotype will lead to significant distortion in the overall fold of OTUD6B. Our findings suggest that compound LOF and ultrarare missense variants may be contribute to the underlying variability expressivity associated with this disorder. In conclusion, our findings support that the clinical severity could be related with the predicted functional severity of the variations in OTUD6B. However, additional functional studies are required.

A New Family with a Novel OTUD6B Mutation: Practicing Whole Exome Sequencing for Antenatal Diagnosis of Tetralogy of Fallot.

OTUD6B, which encodes a member of the ovarian tumor domain-containing deubiquitinating enzyme, has recently been associated with autosomal recessive intellectual disability syndrome with seizures and dysmorphic features. Here, we report one additional case with Tetralogy of Fallot (ToF), who has microcephaly and dysmorphic features along with renal parenchymal disease with simple cortical cysts. The family's first pregnancy was medically terminated due to antenatal diagnosis of ToF. A novel homozygous variant in OTUD6B (c.815T>G; p.[Ile272Arg]) was revealed by whole exome sequencing (WES) along with a previously reported heterozygous PKD1 variant, unraveling the blended phenotype observed in the proband. Our findings highlight the importance of WES for the prenatal diagnosis of ToF and expand the OTUD6B mutational spectrum.

Compound Heterozygote of Point Mutation and Chromosomal Microdeletion Involving OTUD6B Coinciding with ZMIZ1 Variant in Syndromic Intellectual Disability.

The OTUD6B and ZMIZ1 genes were recently identified as causes of syndromic intellectual disability (ID) with shared phenotypes of facial dysmorphism, distal limb anomalies, and seizure disorders. OTUD6B- and ZMIZ1-related ID are inherited in autosomal recessive and autosomal dominant patterns, respectively. We report a 5-year-old girl with developmental delay, facial phenotypes resembling Williams syndrome, and cardiac defects. The patient also had terminal broadening of the fingers and polydactyly. Cytogenomic microarray (CMA), whole exome sequencing (WES), and mRNA analysis were performed. The CMA showed a paternally inherited 0.118 Mb deletion of 8q21.3, chr8:92084087-92202189, with OTUD6B involved. The WES identified a hemizygous OTUD6B variant, c.873delA (p.Lys291AsnfsTer3). The mother was heterozygous for this allele. The WES also demonstrated a heterozygous ZMIZ1 variant, c.1491 + 2T > C, in the patient and her father. This ZMIZ1 variant yielded exon 14 skipping, as evidenced by mRNA study. We suggest that Williams syndrome-like phenotypes, namely, periorbital edema, hanging cheek, and long and smooth philtrum represent expanded phenotypes of OTUD6B-related ID. Our data expand the genotypic spectrum of OTUD6B- and ZMIZ1-related disorders. This is the first reported case of a compound heterozygote featuring point mutation, chromosomal microdeletion of OTUD6B, and the unique event of OTUD6B, coupled with ZMIZ1 variants.

Studying OTUD6B-OTUB1 Protein-Protein Interaction by Low-Throughput GFP-Trap Assays and High-Throughput AlphaScreen Assays.

Protein-protein interactions (PPI) are involved in a myriad of cellular processes, and their deregulation can lead to many diseases. One such process is protein ubiquitination that requires an orchestrated action of three key enzymes to add ubiquitin moieties to substrate proteins. Importantly, this process is reversible through deubiquitinating enzymes. Both ubiquitination and deubiquitination require many PPIs that once classified can be utilized to identify small molecule inhibitors counteracting these reactions. Here, we study the protein-protein interaction between the two deubiquitinating enzymes OTUB1 and OTUD6B and report for the first time that both proteins directly interact with each other. We describe the GFP-Trap immunoprecipitation as a cell-based method to analyze the OTUD6B-OTUB1 interaction in the cellular context and the AlphaScreen (amplified luminescent proximity homogeneous assay) assay as a tool to detect direct interactions and to search for PPI inhibitors.

LncRNA OTUD6B-AS1 Induces Cisplatin Resistance in Cervical Cancer Cells Through Up-Regulating Cyclin D2 via miR-206.

Cervical cancer is one of the most common gynecological cancers. Cisplatin resistance remains a major hurdle in the successful treatment of cervical cancer. Aberrant expression of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are implicated in cisplatin resistance. However, the regulatory functions of lncRNAs and miRNAs in cervical cancer cisplatin resistance and the underlying mechanisms are still elusive. Our qRT-PCR assays verified that miR-206 levels were down-regulated in cisplatin-resistant cervical cancer cells. The introduction of miR-206 sensitized cisplatin-resistant cervical cancer cells to cisplatin. Our qRT-PCR and luciferase reporter assays showed that Cyclin D2 (CCND2) was the direct target for miR-206 in cervical cancer cells. The cisplatin-resistant cervical cancer cells expressed higher CCND2 expression than the parental cells, whereas inhibition of CCND2 could sensitize the resistant cells to cisplatin treatment. Furthermore, we demonstrated that lncRNA OTUD6B-AS1 was up-regulated in cisplatin-resistant cervical cancer cells, and knocking down OTUD6B-AS1 expression induced re-acquirement of chemosensitivity to cisplatin in cervical cancer cells. We also showed that OTUD6B-AS1 up-regulated the expression of CCND2 by sponging miR-206. Low miR-206 and high OTUD6B-AS1 expression were associated with significantly poorer overall survival. Taken together, these results suggest that OTUD6B-AS1-mediated down-regulation of miR-206 increases CCND2 expression, leading to cisplatin resistance. Modulation of these molecules may be a therapeutic approach for cisplatin-resistant cervical cancer.

LncRNA OTUD6B-AS1 inhibits many cellular processes in colorectal cancer by sponging miR-21-5p and regulating PNRC2.

Accumulating evidence has revealed that long noncoding RNAs (lncRNAs) play essential roles in regulating cellular process of various cancers. There have been many studies on the biological functions of lncRNAs in colorectal cancer (CRC). In this research, we explored the role and mechanism of lncRNA ovarian tumor domain containing 6B antisense RNA1 (OTUD6B-AS1) in CRC. Here, we detected OTUD6B-AS1 expression in CRC tissues and cells by RT-qPCR. Functional experiments were performed to test alterations in different cellular processes. Moreover, to verify the binding ability among the indicated RNA molecules, we carried out RIP, RNA pull-down and luciferase reporter assays. According to our data, OTUD6B-AS1 expression was low in CRC tissues and cells. Functionally, overexpression of OTUD6B-AS1 inhibited cell proliferation, migration, invasion and EMT, and promoted cell apoptosis. Bioinformatic analysis and mechanistical experiments confirmed that OTUD6B-AS1 could act as a competitive endogenous RNA (ceRNA) to upregulate Proline-Rich Nuclear Receptor Coactivator 2 (PNRC2) expression by sequestering miR-21-5p. Further rescue experiments validated the inhibitory function of the OTUD6B-AS1/miR-21-5p/PNRC2 axis in cellular process of CRC. Overall, OTUD6B-AS1 inhibits cellular development in CRC by sponging miR-21-5p and upregulating PNRC2, providing a novel insight into the exploration on CRC treatment.

Comparison of Genetic Variants and Manifestations of OTUD6B-Related Disorder: The First Mexican Case.

The intellectual disability syndrome characterized by seizures and dysmorphic features was initially described in 2017 and was associated with genetic variants in the OTUD6B gene, identified by exome sequencing (ES) in a large cohort. This multisystem disorder primarily affects the central nervous system, the gastrointestinal, and the skeletal systems. In this article, we describe the first Mexican patient diagnosed by ES. The homozygous c.433C>T (p.Arg145*) variant of the OTUD6B gene confirmed this intellectual disability syndrome. In addition to seizures and other more frequently reported manifestations of this condition, this is the third patient with associated hypothyroidism and hypogammaglobulinemia, underscoring the value of screening for these conditions in other patients. The current challenge with this patient is to ensure medical management of his seizures and provide him with a better quality of life. The possibilities of additional therapeutic approaches may increase by understanding the physiopathology of the involved pathways.

Deubiquitylase OTUD6B Governs pVHL Stability in an Enzyme-Independent Manner and Suppresses Hepatocellular Carcinoma Metastasis.

Hypoxia inducible factors (HIFs) are the key transcription factors that allow cancer cells to survive hypoxia. HIF's stability is mainly controlled by von Hippel-Lindau (pVHL)-mediated ubiquitylation. Unlike sporadic clear-cell renal carcinomas, VHL mutation is rarely observed in hepatocellular carcinoma (HCC) and the regulatory mechanisms of pVHL-HIF signaling remain elusive. Here, it is shown that deubiquitylase ovarian tumor domain-containing 6B (OTUD6B) suppresses HCC metastasis through inhibiting the HIF activity. OTUD6B directly interacts with pVHL, decreases its ubiquitylation and proteasomal degradation to reduce HIF-1α accumulation in HCC cells under hypoxia. Surprisingly, OTUD6B limits the ubiquitylation of pVHL independent of its deubiquitylase activity. OTUD6B couples pVHL and elongin B/C to form more CBCVHL ligase complex, which protects pVHL from proteasomal degradation. Depletion of OTUD6B results in the dissociation of CBCVHL complex and the degradation of pVHL by Trp Asp repeat and suppressors of cytokine signaling box-containing protein 1 (WSB1). In human HCC tissues, the protein level of OTUD6B is positively correlated with pVHL, but negatively with HIF-1α and vascular endothelial growth factor. Low expression of OTUD6B predicts poor patient survival. Furthermore, OTUD6B gene is a direct transcriptional target of HIF-1α and upregulated upon hypoxia. These results indicate a previously unrecognized feedback loop consisting of OTUD6B, pVHL, and HIF-1α, and provide insights into the targeted hypoxic microenvironment for HCC therapy.

OTUD6B-AS1 Inhibits Viability, Migration, and Invasion of Thyroid Carcinoma by Targeting miR-183-5p and miR-21.

Background: The long noncoding RNA (lncRNA) functions as a regulator of initiation, progression, and metastasis of thyroid carcinomas. lncRNA OTUD6B antisense RNA 1 (OTUD6B-AS1) is a tumor-suppressive noncoding RNA in clear cell renal cell carcinoma. The role of OTUD6B-AS1 in thyroid carcinomas has not been reported yet. We aim to investigate the expression and biological functions of OTUD6B-AS1 in thyroid carcinomas. Methods: The expression level of OTUD6B-AS1 was measured in 60 paired human thyroid carcinoma tissues and corresponding adjacent normal thyroid tissues. The correlations between the OTUD6B-AS1 expression levels and clinicopathological features were evaluated using the Mann-Whitney test. The effects of OTUD6B-AS1 on thyroid carcinoma cells were determined via the MTT and transwell assays. The potential targets of OTUD6B-AS1 were screened using the online programs OncomiR and StarBase 3.0, and the LncBase Predicted v.2. Luciferase reporter assay was used to confirm the interactions between OTUD6B-AS1 and its potential targets. Results: OTUD6B-AS1 was downregulated in thyroid carcinoma tissue samples. The expression of OTUD6B-AS1 correlated with tumor size, clinical stage, and lymphatic metastasis of thyroid carcinoma. Overexpression of OTUD6B-AS1 significantly decreased the viability, migration, and invasion of thyroid carcinoma cells. Online programs predicted miR-183-5p and miR-21 as potential targets of OTUD6B-AS1. Luciferase reporter assays showed miR-183-5p and miR-21 bound to OTUD6B-AS1. Moreover, overexpression of miR-183-5p and miR-21 compromised the inhibitory effects of OTUD6B-AS1 on viability, migration, and invasion of thyroid carcinoma cells. Conclusions: Taken together, our findings present in vitro evidence of lncRNA OTUD6B-AS1 as a tumor suppressor in thyroid carcinomas. OTUD6B-AS1 inhibits viability, migration, and invasion of thyroid carcinoma by targeting miR-183-5p and miR-21.