Influence of ABC stroke score on late recurrence of paroxysmal atrial fibrillation following radiofrequency catheter ablation.

BACKGROUND: In this study we investigated the impact of ABC stroke score on the recurrence of paroxysmal atrial fibrillation (PAF) following radiofrequency catheter ablation (RFCA). METHODS: A total of 132 patients with PAF who underwent RFCA from October 2018 to September 2019 were included in this study. During the first phase of this study the patients were categorized into two groups based on late recurrence of atrial fibrillation after RFCA. In the second phase, the patients were further divided into two groups based on whether their ABC stroke score was ≥ 6.5. RESULT: The univariate analysis indicated that the risk factors for late recurrence of PAF included early recurrence, ABC stroke score, CHA2DS2-VASc score, and NT-proBNP (P < 0.05). Cox multivariate regression analysis revealed that ABC stroke score (P = 0.006) and early recurrence (P = 0.000) were independent predictors of late recurrence, and ABC stroke score ≥ 6.5 was a risk for predicting recurrence of PAF after RFCA with a sensitivity of 66.7% and specificity of 65.7%. After the completion of the 1:1 matching, the univariate Cox analysis indicated that an elevated score of ABC stroke (≥ 6.5) was an independent predictor of late recurrence of PAF (HR = 2.687, 95% CI: 1.036-6.971, P = 0.042). However, using an ABC stroke score cut off at 6.4 predicted the recurrence of atrial tachyarrhythmia with 85% sensitivity and 58.5% specificity. CONCLUSION: An ABC stroke score ≥ 6.4 is a predictor for late recurrence of PAF after RFCA.

PSMD14 stabilizes estrogen signaling and facilitates breast cancer progression via deubiquitinating ERα.

The over-activation of ERα signaling is regarded as the major driver for luminal breast cancers, which could be effective controlled via selective estrogen receptor modulators (SERM), such as tamoxifen. The endocrine resistance is still a challenge for breast cancer treatment, while recently studies implicate the post-translational modification on ERα play important roles in endocrine resistance. The stability of ERα protein and ERα transcriptome are subject to a balance between E3 ubiquitin ligases and deubiquitinases. Through deubiquitinases siRNA library screening, we discover PSMD14 as a critical deubiquitinase for ERα signaling and breast cancer progression. PSMD14 could facilitate breast cancer progression through ERα signaling in vitro and in vivo, while pharmaceutical inhibition of PSMD14 via Thiolutin could block the tumorigenesis in breast cancer. In endocrine resistant models, PSMD14 inhibition could de-stabilize the resistant form of ERα (Y537S) and restore tamoxifen sensitivity. Molecular studies reveal that PSMD14 could inhibition K48-linked poly-ubiquitination on ERα, facilitate ERα transcriptome. Interestingly, ChIP assay shows that ERα could bind to the promoter region of PSMD14 and facilitate its gene transcription, which indicates PSMD14 is both the upstream modulator and downstream target for ERα signaling in breast cancer. In general, we identified a novel positive feedback loop between PSMD14 and ERα signaling in breast cancer progression, while blockade of PSMD14 could be a plausible strategy for luminal breast cancer.

Regulation of the Hippo/YAP axis by CXCR7 in the tumorigenesis of gastric cancer.

BACKGROUND: The Hippo pathway is crucial in organ size control and tumorigenesis. Dysregulation of the Hippo/YAP axis is commonly observed in gastric cancer, while effective therapeutic targets for the Hippo/YAP axis are lacking. Identification of reliable drug targets and the underlying mechanisms that could inhibit the activity of the Hippo/YAP axis and gastric cancer progression is urgently needed. METHODS: We used several gastric cancer cell lines and xenograft models and performed immunoblotting, qPCR, and in vivo studies to investigate the function of CXCR7 in gastric cancer progression. RESULTS: In our current study, we demonstrate that the membrane receptor CXCR7 (C-X-C chemokine receptor 7) is an important modulator of the Hippo/YAP axis. The activation of CXCR7 could stimulate gastric cancer cell progression through the Hippo/YAP axis in vitro and in vivo, while pharmaceutical inhibition of CXCR7 via ACT-1004-1239 could block tumorigenesis in gastric cancer. Molecular studies revealed that the activation of CXCR7 could dephosphorylate YAP and facilitate YAP nuclear accumulation and transcriptional activation in gastric cancer. CXCR7 functions via G-protein Gαq/11 and Rho GTPase to activate YAP activity. Interestingly, ChIP assays showed that YAP could bind to the promoter region of CXCR7 and facilitate its gene transcription, which indicates that CXCR7 is both the upstream signalling and downstream target of the Hippo/YAP axis in gastric cancer. CONCLUSION: In general, we identified a novel positive feedback loop between CXCR7 and the Hippo/YAP axis, and blockade of CXCR7 could be a plausible strategy for gastric cancer.

CircABCA13 acts as a miR-4429 sponge to facilitate esophageal squamous cell carcinoma development by stabilizing SRXN1.

Circular RNAs (circRNAs) play a pivotal role in the tumorigenesis and progression of various cancers. However, the role and mechanisms of circABCA13 in esophageal squamous cell carcinoma (ESCC) are largely unknown. Here, we reported that circABCA13, a novel circular RNA generated by back-splicing of the intron of the ABCA13 gene, is highly expressed in ESCC tumor tissues and cell lines. Upregulation of circABCA13 correlated with TNM stage and a poor prognosis in ESCC patients. While knockdown of circABCA13 in ESCC cells significantly reduced cell proliferation, migration, invasion, and anchorage-independent growth, overexpression of circABCA13 facilitated tumor growth both in vitro and in vivo. In addition, circABCA13 directly binds to miR-4429 and sequesters miR-4429 from its endogenous target, SRXN1 mRNA, which subsequently upregulates SRXN1 and promotes ESCC progression. Consistently, overexpression of miR-4429 or knockdown of SRXN1 abolished malignant behavior promotion of ESCC results from circABCA13 overexpression in vitro and in vivo. Collectively, our study uncovered the oncogenic role of circABCA13 and its mechanism in ESCC, suggesting that circABCA13 could be a potential therapeutic target and a predictive biomarker for ESCC patients.

RBCK1 regulates the progression of ER-positive breast cancer through the HIF1α signaling.

Breast cancer is the most common malignancy in women on a global scale. It can generally be divided into four main categories, of which estrogen receptor ER-positive breast cancer accounts for most breast cancer cases. RBCK1 protein is an E3 ubiquitin ligase containing the UBL, NZF, and RBR domains. It is well known to exhibit abnormal expression in breast tumors, making it a valuable diagnostic marker and drug target. Additionally, studies have confirmed that in breast cancer, about 25 to 40% of tumors appear as visible hypoxic regions, while in hypoxia, tumor cells can activate the hypoxia-inducing factor HIF1 pathway and widely activate the expression of downstream genes. Previous studies have confirmed that in the hypoxic environment of tumors, HIF1α promotes the remodeling of extracellular matrix, induces the recruitment of tumor-associated macrophages (TAM) and immunosuppression of allogeneic tumors, thereby influencing tumor recurrence and metastasis. This research aims to identify RBCK1 as an important regulator of HIF1α signaling pathway. Targeted therapy with RBCK1 could be a promising treatment strategy for ER-positive breast cancer.

RNF31 represses cell progression and immune evasion via YAP/PD-L1 suppression in triple negative breast Cancer.

BACKGROUND: Recently genome-based studies revealed that the abnormality of Hippo signaling is pervasive in TNBC and played important role in cancer progression. RING finger protein 31 (RNF31) comes to RING family E3 ubiquitin ligase. Our previously published studies have revealed RNF31 is elevated in ER positive breast cancer via activating estrogen signaling and suppressing P53 pathway. METHODS: We used several TNBC cell lines and xenograft models and performed immuno-blots, QPCR, in vivo studies to investigate the function of RNF31 in TNBC progression. RESULT: Here, we demonstrate that RNF31 plays tumor suppressive function in triple negative breast cancer (TNBC). RNF31 depletion increased TNBC cell proliferation and migration in vitro and in vitro. RNF31 depletion in TNBC coupled with global genomic expression profiling indicated Hippo signaling could be the potential target for RNF31 to exert its function. Further data showed that RNF31 depletion could increase the level of YAP protein, and Hippo signaling target genes expression in several TNBC cell lines, while clinical data illustrated that RNF31 expression correlated with longer relapse-free survival in TNBC patients and reversely correlated with YAP protein level. The molecular biology assays implicated that RNF31 could associate with YAP protein, facilitate YAP poly-ubiquitination and degradation at YAP K76 sites. Interestingly, RNF31 could also repress PDL1 expression and sensitive TNBC immunotherapy via inhibiting Hippo/YAP/PDL1 axis. CONCLUSIONS: Our study revealed the multi-faced function of RNF31 in different subtypes of breast malignancies, while activation RNF31 could be a plausible strategy for TNBC therapeutics.

RBCK1 is an endogenous inhibitor for triple negative breast cancer via hippo/YAP axis.

BACKGROUND: Triple negative breast cancer (TNBC) is one of the most lethal breast cancer subtypes. Due to a lack of effective therapeutic targets, chemotherapy is still the main medical treatment for TNBC patients. Thus, it is important and necessary to find new therapeutic targets for TNBC. Recent genomic studies implicated the Hippo / Yap signal is over activated in TNBC, manifesting it plays a key role in TNBC carcinogenesis and cancer progression. RBCK1 was firstly identified as an important component for linear ubiquitin assembly complex (LUBAC) and facilitates NFKB signaling in immune response. Further studies showed RBCK1 also facilitated luminal type breast cancer growth and endocrine resistance via trans-activation estrogen receptor alpha. METHODS: RBCK1 and YAP protein expression levels were measured by western blotting, while the mRNA levels of YAP target genes were measured by RT-PCR. RNA sequencing data were analyzed by Ingenuity Pathway Analysis. Identification of Hippo signaling activity was accomplished with luciferase assays, RT-PCR and western blotting. Protein stability assays and ubiquitin assays were used to detect YAP protein degradation. Ubiquitin-based immunoprecipitation assays were used to detect the specific ubiquitination modification on the YAP protein. RESULTS: In our current study, our data revealed an opposite function for RBCK1 in TNBC progression. RBCK1 over-expression inhibited TNBC cell progression in vitro and in vivo, while RBCK1 depletion promoted TNBC cell invasion. The whole genomic expression profiling showed that RBCK1 depletion activated Hippo/YAP axis. RBCK1 depletion increased YAP protein level and Hippo target gene expression in TNBC. The molecular biology studies confirmed that RBCK1 could bind to YAP protein and enhance the stability of YAP protein by promoting YAP K48-linked poly-ubiquitination at several YAP lysine sites (K76, K204 and K321). CONCLUSION: Our study revealed the multi-faced RBCK1 function in different subtypes of breast cancer patients and a promising therapeutic target for TNBC treatment. Video abstract.

OTUB1 suppresses Hippo signaling via modulating YAP protein in gastric cancer.

Gastric cancer is one of the most lethal human malignancies in the world. Although great efforts are put in developing novel therapeutic targets, the effective targeting drugs are still limited. Recent studies reveal the abnormality of Hippo/YAP axis play critical role in the oncogenic process of gastric cancer. It is of great importance to demonstrate the regulation of Hippo signaling activity and YAP protein turnover in gastric cancer. Besides, the phosphorylation cascade on YAP function, which has been thoroughly investigated, the ubiquitination of YAP is also important in Hippo signaling status. Here, We utilized the DUB (Deubiquitinase) siRNA library to identify critical DUB for Hippo signaling. We discovered OTUB1 as a critical factor to facilitate gastric cancer cell stemness and progression, which deubiquitinated and stabilized YAP protein. The clinical data analysis implicated OTUB1 was higher expressed in gastric cancer, which correlated with YAP activity and poor survival. OUTB1 interacted with YAP protein via its OTU domain (Ovarian tumor domain) and deubiquitinated YAP at several lysine sites (K90, K280, K343, K494 and K497), which subsequently inhibited YAP degradation. Our study revealed a novel deubiquitinase of Hippo/YAP axis and one possible therapeutic target for YAP-driven gastric cancer.

DUB1 suppresses Hippo signaling by modulating TAZ protein expression in gastric cancer.

BACKGROUND: The Hippo pathway functions as a tumor suppressor pathway in human cancers, while dysfunction of the Hippo pathway is frequently observed in malignancies. Although YAP/TAZ activity is tightly controlled by the phosphorylation cascade of the MST-LATS-YAP/TAZ axis, it is still unclear why the YAP/TAZ proteins are activated in human cancers despite Hippo pathway activation. Recent studies have suggested that in addition to phosphorylation, several other posttranslational modifications, including ubiquitination, also play critical roles in modulating TAZ function. METHODS: We used several gastric cancer cell lines and performed western blot analysis, real-time PCR, immunoprecipitation assays, and in vitro ubiquitination assays and established a xenograft mouse model. RESULTS: Here, by screening a DUB (deubiquitinase) siRNA library, we discovered that DUB1 functions as a critical modulator that facilitates gastric cancer stemness and progression by deubiquitinating and activating the TAZ protein. We also found that DUB1 expression was elevated in gastric cancer and that elevated DUB1 expression correlated with TAZ activation and poor survival. DUB1 associates with the TAZ protein and deubiquitinates TAZ at several lysine residues, which subsequently stabilizes TAZ and facilitates its function. CONCLUSIONS: Our study revealed a novel deubiquitinase in the Hippo/TAZ axis and identified one possible therapeutic target for Hippo-driven gastric cancer.

YAP inhibits ERα and ER+ breast cancer growth by disrupting a TEAD-ERα signaling axis.

Hippo signaling restricts tissue growth by inhibiting the transcriptional effector YAP. Here we uncover a role of Hippo signaling and a tumor suppressor function of YAP in estrogen receptor positive (ER+) breast cancer. We find that inhibition of Hippo/MST1/2 or activation of YAP blocks the ERα transcriptional program and ER+ breast cancer growth. Mechanistically, the Hippo pathway transcription factor TEAD physically interacts with ERα to increase its promoter/enhancer occupancy whereas YAP inhibits ERα/TEAD interaction, decreases ERα occupancy on its target promoters/enhancers, and promotes ERα degradation by the proteasome. Furthermore, YAP inhibits hormone-independent transcription of ERα gene (ESR1). Consistently, high levels of YAP correlate with good prognosis of ER+ breast cancer patients. Finally, we find that pharmacological inhibition of Hippo/MST1/2 impeded tumor growth driven by hormone therapy resistant ERα mutants, suggesting that targeting the Hippo-YAP-TEAD signaling axis could be a potential therapeutical strategy to overcome endocrine therapy resistance conferred by ERα mutants.

TRIM3 facilitates estrogen signaling and modulates breast cancer cell progression.

BACKGROUND: Breast cancer is the most common cancer in women worldwide. More than 70% of breast cancers are estrogen receptor (ER) alpha positive. Compared with ER alpha-negative breast cancer, which is more aggressive and has a shorter survival time, ER alpha-positive breast cancer could benefit from endocrine therapy. Selective estrogen receptor modulators, such as tamoxifen, are widely used in endocrine therapy. Approximately half of ER alpha-positive breast cancer patients will eventually develop endocrine resistance, making it a major clinical challenge in therapy. Thus, decoding the throughput of estrogen signaling, including the control of ER alpha expression and stability, is critical for the improvement of breast cancer therapeutics. METHODS: TRIM3 and ER alpha protein expression levels were measured by western blotting, while the mRNA levels of ER alpha target genes were measured by RT-PCR. A CCK-8 assay was used to measure cell viability. RNA sequencing data were analyzed by Ingenuity Pathway Analysis. Identification of ER alpha signaling activity was accomplished with luciferase assays, RT-PCR and western blotting. Protein stability assays and ubiquitin assays were used to detect ER alpha protein degradation. Ubiquitin-based immunoprecipitation assays were used to detect the specific ubiquitination modification on the ER alpha protein. RESULTS: In our current study, we found that TRIM3, an E3 ligase, can promote ER alpha signaling activity and breast cancer progression. TRIM3 depletion inhibits breast cancer cell proliferation and migration, while unbiased RNA sequencing data indicated that TRIM3 is required for the activity of estrogen signaling on the -genome-wide scale. The immunoprecipitation assays indicated that TRIM3 associates with ER alpha and promotes its stability, possibly by inducing K63-linked polyubiquitination of ER alpha. In conclusion, our data implicate a nongenomic mechanism by which TRIM3 stabilizes the ER alpha protein to control ER alpha target gene expression linked to breast cancer progression. CONCLUSION: Our study provides a novel posttranslational mechanism in estrogen signaling. Modulation of TRIM3 expression or function could be an interesting approach for breast cancer treatment. Video abstract.

Regulation of P53 signaling in breast cancer by the E3 ubiquitin ligase RNF187.

The tumor suppressor P53 plays critical role in preventing cancer. P53 is rarely mutated and remains functional in luminal-type breast cancer(1). According to current knowledge, wild-type P53 function is tightly controlled by posttranslational modifications, such as ubiquitination. Several ubiquitin ligases have been shown to regulate P53 ubiquitination and protein stability. Here, we report that RNF187, a RING family ubiquitin ligase, facilitates breast cancer growth and inhibits apoptosis by modulating P53 signaling. RNF187 expression was elevated in breast cancer and correlated with breast cancer survival only in the P53 wild-type groups. Bioinformatic analysis showed that the expression of RNF187 was negatively correlated with the expression of P53 target genes, such as IGFBP3 and FAS, in breast cancer. RNF187 depletion inhibited breast cancer growth and facilitated cell death. RNA sequencing analysis indicated that RNF187 could be an important modulator of P53 signaling. Further experiments showed that RNF187 interacts with P53 and promotes its degradation by facilitating its polyubiquitination in breast cancer cells. Interestingly, the in vitro ubiquitin assay showed that RNF187 can directly ubiquitinate P53 in a manner independent of MDM2. These findings reveal a novel direct P53 regulator and a potential therapeutic target for breast cancer.

The E3 Ubiquitin Ligase HOIP inhibits Cancer Cell Apoptosis via modulating PTEN stability.

Chemotherapy is widely used in a variety of solid tumors, such as lung cancer, gastric cancer and breast cancer. The genotoxic drugs, such as cisplatin, suppress cancer progression either by inhibition cell proliferation or facilitating apoptosis. However, the chemotherapy resistance remains an urgent challenge in cancer therapy, especially in advanced stages. Several studies showed that the activation of pro-survival pathways, such as PI3K-AKT, participated in mediating chemotherapy resistance. The insights into the molecular mechanisms for underlying chemotherapy resistance are of great importance to improve cancer patient survival in advanced stages. The HOIP protein belongs to the RING family E3 ubiquitin ligases and modulates several atypical ubiquitination processes in cellular signaling. Previous studies showed that HOIP might be an important effector in modulating cancer cell death under genotoxic drugs. Here, we report that HOIP associates with PTEN and facilitates PTEN degradation in cancer cells. Depletion of HOIP causes cell cycle arrest and apoptosis, which effects could be rescued by PTEN silencing. Besides, the survival data from public available database show that HOIP expression correlates with poor survival in several types of chemotherapy-treated cancer patients. In conclusion, our study establishes a novel mechanism by which HOIP modulates PTEN stability and facilitates chemotherapy resistance in malignancies.

ZNF213 negatively controls triple negative breast cancer progression via Hippo/YAP signaling.

Breast cancer is one of the most commonly diagnosed malignancies worldwide, while the triple negative breast cancer (TNBC) is the most aggressive and virulent subtype in breast cancers. Compared with luminal type breast cancers, which could be well controlled by endocrine treatment, TNBC is worse in prognosis and lack of effective targeted therapy. Thus, it would be interesting and meaningful to identify novel therapeutic targets for TNBC treatments. Recent genomic data showed the activation of Hippo/YAP signaling in TNBC, indicating its critical roles in TNBC carcinogenesis and cancer progression. Hippo/YAP signaling could subject to several kinds of protein modifications, including ubiquitination and phosphorylation. Quite a few studies have demonstrated these modifications, which controlled YAP protein stability and turnover, played critical role in Hippo signaling activation In our current study, we identified ZNF213 as a negative modifier for Hippo/YAP axis. ZNF213 depletion promoted TNBC cell migration and invasion, which could be rescued by further YAP silencing. ZNF213 knocking down facilitated YAP protein stability and Hippo target gene expression, including CTGF and CYR61. Further mechanism studies demonstrated that ZNF213 associated with YAP and facilitated YAP K48-linked poly-ubiquitination at several YAP lysine sites (K252, K254, K321 and K497). Besides, the clinical data showed that ZNF213 negatively correlated with YAP protein level and Hippo target gene expression in TNBC samples. ZNF213 expression correlated with good prognosis in TNBC patients. Our data provided novel insights in YAP proteolytic regulation and TNBC progression.

ZNF213 Facilitates ER Alpha Signaling in Breast Cancer Cells.

BACKGROUND: Breast cancer is the most common women malignancy worldwide, while estrogen receptor alpha positive type accounts for two third of all breast cancers. Although ER alpha positive breast cancer could be effectively controlled by endocrine therapy, more than half of the cases could develop endocrine resistance, making it an important clinical issue in breast cancer treatment. Thus, decoding the detailed mechanism, which controls ER alpha signaling activation and ER alpha protein stability, is of great importance for the improvement of breast cancer therapy. Several zinc finger proteins were shown to mediate the ubiquitination process and modulate protein stability. Thus, we further explore the function of Zinc finger protein 213 on ER alpha protein stability and tamoxifen resistance. METHODS: CCK8 and Edu assay was used to measure cell proliferation. RNA sequence was performed by Ingenuity pathway analysis. The ER alpha signaling activities were measured with luciferase assay, real-time quantitative PCR, and western blotting. Protein stability assay and ubiquitin assay were used to determine ER alpha protein degradation and ubiquitination. The immuno-precipitation was utilized to determine ER alpha and ZNF213 interaction. The ubiquitin-based immuno-precipitation assay was sued to detect specific ubiquitination manner on ER alpha. RESULTS: We identified ZNF213 as a novel zinc finger protein, which modulated ER alpha protein. ZNF213 expression correlated with poor outcome in endocrine treated patients. ZNF213 depletion inhibited ER alpha signaling and proliferation in breast cancer cells. Further mechanistic studies showed ZNF213 located in cytosol and nuclear, which modulated ER alpha stability via inhibiting ER alpha K48-linked ubiquitination. CONCLUSIONS: Our study reveals an interesting post-translational mechanism between ER alpha and ZNF213 in breast cancer. Targeting ZNF213 could be an appealing strategy for ER alpha positive breast cancer.

The deubiquitinating enzyme USP1 modulates ERα and modulates breast cancer progression.

Breast cancer is one of the most common malignancies worldwide, while the luminal types (ERα positive) accounts for two third of all breast cancer cases. Although ERα positive breast cancer could be effective controlled by endocrine therapy, most of the patients will develop endocrine resistance, which becomes a headache clinical issue for breast cancer field. Endocrine resistance could be caused by multiple pathway disorders, the dys-regulation of ERα signaling might be a critical factor, which makes it urgent and important to reveal the potential molecular mechanism of ERα signaling. In our current study, we identified a new deubiquitination enzyme USP1 through screening the whole DUB (Deubiquitinases) siRNA library. The expression of USP1 is elevated in human breast cancer compared with normal mammary tissues. Importantly, USP1 expression levels are specially correlated with poor survival in ERα positive patients. USP1 depletion inhibited breast cancer cell progression and ERα signaling activity. Immuno-precipitation assays indicate that USP1 associates with ERα and promotes its stability possibly via inhibiting ERα K48-linked poly-ubiquitination. In conclusion, our data implicate a non-genomic mechanism by USP1 via stabilizing ERα protein controls ERα target gene expression linked to breast cancer progression.

Regulation of Hippo/YAP signaling and Esophageal Squamous Carcinoma progression by an E3 ubiquitin ligase PARK2.

Objective: Esophageal squamous cell carcinoma (ESCC) is one of the most commonly diagnosed cancer types in China. Recent genomic sequencing analysis indicated the over-activation of Hippo/YAP signaling might play important roles for the carcinogenic process and progression for ESCC patients. However, little is known about the molecular mechanisms that controls Hippo signaling activity in ESCC. Our previous studies indicated that PLCE1-an important risk factor for ESCC-linked to ESCC progression through snail signaling, during this period, we found PARK2 was an important downstream target of PLCE1-snail axis. PARK2 was decreased in ESCC human samples, and correlated with good prognosis in ESCC patients. Further research showed that PARK2 could inhibit YAP, which functions as key downstream effectors of the Hippo pathway. Here, we aim to reveal the molecular mechanisms of PARK2 modulated Hippo pathway in ESCC. Methods: To evaluate the function of PARK2 in ESCC, we used a tissue microarray (TMA) of 223 human ESCC patients and immunohistochemistry to analyze the correlation between PARK2 expression and clinicopathologic variables. Depletion of endogenous PARK2 and YAP from ESCC cells using CRISPR/Cas9 technologies. Flow cytometry and EdU cell proliferation assay were used to detect proliferation of ESCC cells. Nude mice subcutaneous injection and Ki-67 staining were used to evaluate tumor growth in vivo. Migration and invasion assays were performed. In addition, lung metastasis models in mice were used to validate the function of PARK2 in vivo. Identification of PARK2 involved in hippo pathway was achieved by expression microarray screening, double immunofluorescence staining and co-immunoprecipitation assays. The RNA-seq analysis results were validated through quantitative real-time PCR (qRT-PCR) analysis. The protein half-life of YAP was analyzed by Cycloheximide assay, and the TEAD activity was detected by Luciferase reporter assays. Results: Clinical sample of ESCC revealed that low PARK2 expression correlated with late tumor stage (P < 0.001), poor differentiation (P < 0.04), lymph node (P < 0.001) and distant metastasis (P = 0.0087). Multivariate Cox proportional regression analysis further revealed that PARK2 expression (P = 0.032) is an independent prognostic factor for the overall survival of ESCC patients. Besides, the immunohistochemistry results showed that PARK2 negatively correlated with YAP protein level (P < 0.001). PARK2 depletion promotes ESCC progression both through Hippo/YAP axis, while PARK2 overexpression suppresses ESCC tumor progression by Hippo signaling. Co-IP and ubiquitination assays revealed that PARK2 could interact with YAP in the cytosol and promotes YAP K48-linked ubiquitination at K90 sites. Conclusion: Clinical sample analysis and mechanistic study have validated PARK2 as a tumor suppressor for ESCC. Multivariate Cox proportional regression analysis further revealed that PARK2 is an independent prognostic factor for the overall survival of ESCC patients. Cellular and molecular mechanisms in this study showed that PARK2 associated with YAP protein in the cytosol, promoted YAP ubiquitination and proteasome-dependent degradation in ESCC cells. Therefore, as a novel modulator for Hippo signaling, modulation of PARK2 activity or gene expression level could be an appealing strategy to treat esophageal.

RNF181 modulates Hippo signaling and triple negative breast cancer progression.

BACKGROUND: Breast cancer ranks No. 1 in women cancer incidence, while triple negative breast cancer (TNBC) is the most aggressive and the worst prognostic subtype in all breast cancer subtypes. Compared with estrogen receptor alpha positive breast cancer, which could be well controlled by endocrine therapy, TNBC is lack of mature molecular targets for medical therapy. Thus, it is urgent and necessary to discovery the carcinogenic mechanism and potential therapeutic targets for TNBC. Recent studies reveal that Hippo/YAP signaling is an important mediator for TNBC progression. Our current study investigates the role of RING finger protein RNF181 in modulation Hippo/YAP signaling. METHODS: YAP and RN181 protein level were measured by western blot, while the Hippo classical target genes were measured by real-time PCR. WST1 assay were used to measure cell proliferation, the trans-well and wound healing were used to measure the cell migration and invasion capacity. Protein stability and ubiquitin assay were used to detect the YAP protein ubiquitin and stability. The immuno-precipitation assays were used to detect the protein interactions. Immuno-staining was used to detect the protein localization of YAP and RNF181, while the ubiquitin-based immuno-precipitation assays were used to detect the specific ubiquitination manner of YAP. RESULTS: Our current study identified a novel modulator-RNF181 as a positive mediator for Hippo/YAP signaling activation in TNBC. RNF181 depletion significantly inhibited TNBC cell migration, invasion and proliferation, which effect could be rescued by YAP overexpression. RNF181 depletion decreased YAP protein level and Hippo signaling target genes, such as CTGF and CYR61, in TNBC cell lines. Immuno-precipitation assay showed that RNF181 interact with YAP and promoted YAP stability by inhibition K48-linked poly-ubiquitination of YAP in TNBC cells. Besides, public available data showed that RNF181 is elevated in breast cancer and related to poor prognosis in TNBC patients. CONCLUSION: Our study provides evidence to establish a non-proteolytic mechanism in modulating Hippo signaling in breast cancer. RNF181 could be an interesting marker for triple negative breast cancer prognostics and therapeutics.

MicroRNA-547-5p-mediated interleukin-33/suppressor of tumorigenicity 2 signaling underlies the genesis and maintenance of neuropathic pain and is targeted by the therapy with bone marrow stromal cells.

Interleukin-33 (IL-33)/suppressor of tumorigenicity 2 (ST2) signaling is known to promote inflammation and the genesis and maintenance of neuropathic pain. However, it remained mostly unknown how IL-33/ST2 signaling can be enhanced by neuropathic stimulations. Here, we report that the chronic constriction nerve injury (CCI)-induced increases in the expression of IL-33 and ST2 and a decrease in microRNA (miRNA)-547-5p not only in the dorsal root ganglia (DRG) but also in spinal dorsal horn (SDH) ipsilateral to the CCI. We found that increasing endogenous miRNA-547-5p by the intrathecal (i.t.) infusion of agomir-miR-547-5p did not produce any effect in naive rats but blocked the CCI-induced increases in the IL-33 and ST2, and pain sensitivity. The reducing endogenous miRNA-547-5p by the i.t. delivering antagomir-miR-547-5p into naive rats caused significant changes in IL-33 and ST2 expressions in both the DRG and SDH, and pain sensitivity, which were similar to those induced by the CCI. Since increasing IL-33 by the i.t. infusion of recombinant IL-33 produced no change in the expression of miR-547-5p, and the CCI still reduced miR-547-5p expression in rats with the IL-33 knockdown, we conclude that the reduction of miR-547-5p can be an upstream event leading to the enhancement of IL-33/ST2 signaling induced by the CCI. The intravenous application of bone marrow stromal cells (BMSCs) reduced the depression of miR-547-5p in both the DRG and SDH, and pain hypersensitivity produced by the CCI or antagomir-miR547-5p application. However, the BMSC effect was significantly occluded by the pretreatment with miR-547-5p agomir or the IL-33 knockdown, demonstrating a novel mechanism underlying the BMSC therapy.

Regulation of Hippo signaling and triple negative breast cancer progression by an ubiquitin ligase RNF187.

Breast cancer is the most common malignancy for women worldwide, while Triple Negative Breast Cancer (TNBC) accounts for 20% in all patients. Compared with estrogen receptor positive breast cancer, which could be effectively controlled via endocrine therapy, TNBC is more aggressive and worse in prognosis. It is therefore urgent and necessary to develop a novel therapeutic strategy for TNBC treatment. Recent studies identified Hippo signaling is highly activated in TNBC, which could be a driving pathway for TNBC progression. In our study, we determine RNF187 as a negative regulator for Hippo signaling activation. RNF187 depletion significantly decreases cell migration and invasion capacity in TNBC. These effects could be rescued by further YAP depletion. Depletion of RNF187 increases the YAP protein level and Hippo signaling target genes, such as CTGF and CYR61 in TNBC. Immuno-precipitation assay shows that RNF187 associates with YAP, promoting its degradation possibly via inducing YAP K48-dependent poly-ubiquitination. Interestingly, Our clinical data reveals that RNF187 reversely correlates with YAP protein level and Hippo target genes. RNF187 tends to correlate with good prognosis in TNBC patients. Our study provides evidence to establish a proteolytic mechanism in regulation Hippo signaling activation in TNBC.