Significant association of YAP1 and HSPC111 proteins with poor prognosis in Chinese gastric cancer patients

Hypoxia-induced exosomes facilitate lung pre-metastatic niche formation in hepatocellular carcinoma through the miR-4508-RFX1-IL17A-p38 MAPK-NF-κB pathway

Background: Hypoxia plays an important role in the lung metastasis of hepatocellular carcinoma (HCC). However, the process by which hypoxia promotes the formation of a pre-metastatic niche (PMN) and its underlying mechanism remain unclear. Methods: Exosomes derived from normoxic and hypoxic HCC cells were collected to induce fibroblast activation in vitro and PMN formation in vivo. The micro RNA (miR) profiles of the exosomes were sequenced to identify differentially expressed miRNAs. Gain- and loss-of-function analyses were performed to investigate miR-4508 function. Dual-luciferase, western blotting, and real-time reverse transcription-PCR analyses were used to identify the direct targets of miR-4508 and its downstream signaling pathways. To demonstrate the roles of hypoxic tumor-derived exosomes (H-TDEs) and miR-4508 in the lung metastasis of liver cancer, H22 tumor cells were injected through the tail vein of mice. Blood plasma-derived exosomes from patients with HCC who underwent transarterial chemoembolization (TACE) were applied to determine clinical correlations. Results: We demonstrated that H-TDEs activated lung fibroblasts and facilitated PMN formation, thereby promoting lung metastasis in mice. Screening for upregulated exosomal miRNAs revealed that miR-4508 and its target, regulatory factor X1 (RFX1), were involved in H-TDE-induced lung PMN formation. Moreover, miR-4508 was significantly upregulated in plasma exosomes derived from patients with HCC after TACE. We confirmed that the p38 MAPK-NF-κB signaling pathway is involved in RFX1 knockdown-induced fibroblast activation and PMN formation. In addition, IL17A, a downstream target of RFX1, was identified as a link between RFX1 knockdown and p38 MAPK activation in fibroblasts. Conclusion: Hypoxia enhances the release of TDEs enriched with miR-4508, thereby promoting lung PMN formation by targeting the RFX1-IL17A-p38 MAPK-NF-κB pathway. These findings highlight a novel mechanism underlying hypoxia-induced pulmonary metastasis of HCC.

Relationship between Yes-Associated Protein 1 and Prognosis of Digestive System Neoplasm: Quantitative Analysis and Bioinformatics Analysis Based on 4023 Patients

Yes-associated protein 1 (YAP1) is involved in the development of a variety of malignancies. However, the prognosis of malignant digestive tumors with YAP1 expression is still controversial. This study searched 31 articles with 36 data sets of 4023 patients to explore the role of YAP1 expression on the prognosis of digestive malignant tumors by searching the PubMed, Embase, Web of Science, Google Scholar, and Cochrane Library databases. Specifically, relevant cancer expression matrix data were downloaded from The Cancer Genome Atlas (TCGA) database. In this meta-analysis, quantitative analysis showed that the overexpression of YAP1 was not conducive to OS (1.62, 95% CI (1.38, 1.90), P=0.001) and DFS (1.59, 95% CI (1.31, 1.93), P=0.001) in patients with digestive malignant tumors. In addition, TCGA database analysis showed that YAP1 was overexpressed in gastric cancer, cholangiocarcinoma, and colorectal cancer. Survival analysis showed that the patients with high expression of YAP1 in pancreatic cancer have a poor OS (MST: 394 vs. 691 days, P < 0.0001) and DFS (MST: 371 vs. 542 days, P=0.026) prognosis. YAP1 may be a molecular marker that effectively predicts the survival of malignant digestive tumors, especially pancreatic cancer, and is a potential therapeutic target for malignant digestive tumors.

Photosensitizer verteporfin inhibits the growth of YAP- and TAZ-dominant gastric cancer cells by suppressing the anti-apoptotic protein Survivin in a light-independent manner

Yes-associated protein (YAP) positivity indicates a poor prognosis in gastric cancer. Transcriptional co-activator with a PDZ-binding domain (TAZ), a YAP paralog, is highly expressed in gastric signet ring cell carcinoma. Verteporfin (VP), a clinical photosensitizer, was recently shown to inhibit YAP/TAZ. In the present study, the therapeutic potential of VP treatment was explored using two gastric cancer cell lines: MKN-45 (TAZ-dominant) and MKN-74 (YAP-dominant). Cell proliferation was evaluated by MTS assay. Vascular mimicry was evaluated by the tube formation assay. Gene and protein expression levels of YAP/TAZ downstream effectors [such as Survivin, Cysteine-rich angiogenic inducer 61 (CYR61), and connective tissue growth factor (CTGF)] were measured. YAP or TAZ localization was evaluated by immunofluorescence. Cell death was assessed by immunofluorescent staining of Annexin V. YAP and TAZ expression were knocked down by small interfering RNA. The current results demonstrate that MKN-45, a poorly differentiated TAZ-dominant gastric cancer cell line, was more sensitive to VP than MKN-74, a moderately differentiated YAP-dominant gastric cancer cell line. VP changed the localization of YAP/TAZ, promoted its degradation and significantly decreased the protein level of Survivin in both cell lines. Cell death was induced by VP treatment in a dose-dependent manner. Vascular mimicry was inhibited in both cell lines. Proliferation in both cell lines decreased in response to YAP/TAZ knockdown. The present study indicated that VP has potential as a therapeutic agent in YAP- and TAZ-dominant gastric cancers due to its ability to suppress the anti-apoptotic protein Survivin via inhibition of YAP and TAZ.

Clinical significance of YAP1 and TAZ in esophageal squamous cell carcinoma

BACKGROUND

Esophageal cancer is the eighth most frequent and sixth most fatal cancer worldwide. This study aimed to investigate the clinical characteristics and prognostic significance of yes related protein 1 (YAP1) and transcriptional co-activator with PDZ binding motif (TAZ) in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

A total of 306 ESCC pathological specimens and adjacent tissues (as control; tissues from the esophageal mucosa >5 cm from the edge of the tumor) were collected between January, 2008 and December, 2018. Immunohistochemical staining was used to assess the expression of YAP1 and TAZ proteins in the ESCC and adjacent tissues, and their relationship with clinicopathological parameters was evaluated using SPSS 21.0 software.

RESULTS

YAP1 and TAZ proteins were highly expressed in ESCC, and their expression was closely related to TNM stage and lymph node metastasis. Expression of YAP1 was associated with tumor size (P = .029), differentiation (P = .000), depth of invasion (P = .001), and TNM stage (P = .000). Expression of TAZ was associated with tumor size (P = .034), differentiation (P = .000), depth of invasion (P = .029), lymph node metastasis (P = .006), and ethnicity (P < .001). The expression of YAP1 protein was positively correlated with the expression of TAZ protein (r = 0.257, P < .05). YAP1 and TAZ expression (P = .039 and .000, respectively), tumor size (P = .041), and lymph node metastasis (P = .001) significantly affected the overall survival of patients with ESCC, and represent independent factors for overall survival.

CONCLUSION

YAP1 and TAZ proteins are highly expressed in ESCC, and closely related to the clinical and pathological parameters such as the diameter of the tumor, degree of differentiation, and depth of invasion, indicating that YAP1 and TAZ may be involved in the development of ESCC. YAP1 and TAZ may be used as prognostic markers in ESCC.

NUSAP1 Promotes Gastric Cancer Tumorigenesis and Progression by Stabilizing the YAP1 Protein

The Yes-associated protein (YAP1) is a main effector of the canonical Hippo pathway, which contributes greatly to tumor initiation, progression, and metastasis in multiple cancers, including gastric cancer (GC). Due to limited knowledge of YAP1 upregulation in cancer, it is a great challenge of therapeutic targets toward the Hippo-YAP1 pathway. Here, we identify nucleolar spindle-associated protein 1 (NUSAP1) as a novel binding partner of YAP1. The upregulation of NUSAP1 is associated with unfavorable clinical outcomes in GC patients, and NUSAP1 depletion impairs its oncogenic properties in vitro and in a xenograft model. Mechanistically, we discovered that NUSAP1 functions as a positive regulator of YAP1 protein stability, thereby inducing the transcription of Hippo pathway downstream target genes, such as CTGF and CYR61. More interestingly, we find that the cancer-promoting effects of NUSAP1 on GC cell growth, migration, and invasion are mainly mediated by YAP1. Furthermore, aberrant expression of NUSAP1 and YAP1 is highly correlated in GC cell lines and tissues. We herein clarify the role of the oncogenic NUSAP1-YAP1 axis in GC tumorigenesis and progression and, therefore, provide novel therapeutic targets for GC treatment.

Targeting Yes1 Associated Transcriptional Regulator Inhibits Hepatocellular Carcinoma Progression and Improves Sensitivity to Sorafenib: An in vitro and in vivo Study

Purpose

The aim of this study was to investigate the role of Yes1 associated transcriptional regulator (YAP1) in the pathology of hepatocellular carcinoma (HCC) and its potential as a therapeutic target.

Methods

YAP1 expression in HCC and adjacent tissues was determined via immunohistochemistry; in HCC and human normal liver cell lines, expression was examined via Western blotting. The effects of YAP1 knockdown and overexpression were detected following transfection of HCC cells with siRNA-YAP1 recombinants or pcDNA3.1-YAP1 plasmids. A tumor xenograft model was constructed by implanting YAP1-knockdown lentivirus-infected Hep-3B cells into nude mice, and the animals were treated with sorafenib.

Results

In patients with HCC, YAP1 was upregulated in tumor tissue compared with adjacent tissue, and its high expression in the tumor was associated with increased Edmonson grade. In vitro, YAP1 expression was increased in Hep-3B, SK-HEP-1 and Huh7 cells, while it was similar in SMMC-7721 cells and LO2 cells. Meanwhile, YAP1 increased cell proliferation and invasion, promoted the progression of epithelial-mesenchymal transition, and inhibited cell apoptosis in HCC cells; furthermore, YAP1 knockdown combined with the administration of sorafenib decreased cell viability and increased cell apoptosis compared with YAP1 knockdown or treatment with sorafenib alone. In vivo, YAP1 knockdown inhibited tumor growth and metastasis, whereas it promoted apoptosis; meanwhile, YAP1 knockdown synergized with sorafenib to suppress tumor progression in HCC mice.

Conclusion

YAP1 is upregulated in both HCC tumor tissues and cell lines. Moreover, it promotes cell proliferation and invasion and promoted the progression of epithelial-mesenchymal transition in vitro. Furthermore, targeting YAP1 inhibits HCC progression and improves sensitivity to sorafenib in vitro and in vivo.

Up-regulated acylglycerol kinase (AGK) expression associates with gastric cancer progression through the formation of a novel YAP1-AGK-positive loop

Acylglycerol kinase (AGK) uses adenosine triphosphate (ATP) and acylglycerol to generate adenosine diphosphate (ADP) and acyl‐sn‐glycerol 3‐phosphate in cells. Recent evidence has demonstrated that dysregulated AGK expression is associated with the development of various human cancers. This study investigated the effects of AGK on gastric cancer cell proliferation and carcinogenesis and explored the underlying molecular events. AGK expression was up‐regulated in gastric cancer and was associated with poor prognosis in gastric cancer patients. AGK overexpression increased gastric cancer proliferation, invasion capacity and the expression of the epithelial‐mesenchymal transition markers in vitro. Conversely, the knockdown of AGK expression reduced gastric cancer cell proliferation in vitro and in nude mouse tumour cell xenografts. Importantly, AGK expression was associated with the YAP1 expression in gastric cancer cells and tissues. YAP1 expression also transcriptionally induced AGK expression through the binding of TEAD to the AGK gene promoter. However, AGK expression inhibited the activation of the Hippo pathway proteins and induced YAP1 nuclear localization to enhance the transcription activity of YAP1/TEADs. In conclusion, the study demonstrates that AGK is not only a novel target of the Hippo‐YAP1 pathway, but that it also positively regulates YAP1 expression, thus forming a YAP1‐AGK–positive feedback loop.

Sophoridine inhibits lung cancer cell growth and enhances cisplatin sensitivity through activation of the p53 and Hippo signaling pathways

BACKGROUND

Sophoridine, a quinolizidine alkaloid extracted from the Chinese herb Sophora alopecuroides L., has been reported to exert antitumor effects against multiple human cancers. However, few studies have evaluated its tumor-suppressing effects and associated mechanism with respect to lung cancer, in addition to its potential to be used for clinical lung cancer treatment.

METHODS

Different types of lung cancer cells were used to investigate the antitumor effects of sophoridine using cell viability, colony formation, and cell invasion, and migration assays. To determine the signaling pathways involved, western blot analysis, quantitative real-time polymerase chain reaction, an in vivo ubiquitination assay, and immunohistochemistry were used in cellular assays and with a subcutaneous xenograft model in BALB/c mice.

RESULTS

Sophoridine significantly suppressed the proliferation of and colony formation by lung cancer cells in vitro. Transwell assays demonstrated that sophoridine also inhibited invasion and migration in lung cancer cells. In addition, sophoridine enhanced the effects of cisplatin on lung cancer cells. A mechanistic study revealed that sophoridine significantly activated the Hippo and p53 signaling pathways, and mouse xenograft experiments further confirmed in vitro findings in lung cancer cells.

CONCLUSIONS

Taken together, these results suggest that sophoridine can inhibit lung cancer progression and enhance the effects of the anticancer drug cisplatin against lung cancer cells. The mechanism of action of sophoridine might involve the Hippo and p53 signaling pathways.

LncRNA ZEB1-AS1 Regulates Colorectal Cancer Cells by MiR-205/YAP1 Axis

Background

Recent studies demonstrated that long non-coding RNAs (lncRNAs) were involved in many biological processes. Dysregulated lncRNAs are related to many cancers, including colorectal cancer (CRC). However, the molecular mechanism of lncRNA ZEB1-AS1 in CRC is not clear.

Methods

LncRNA ZEB1-AS1, miR-205, and YAP1 expression were measured by quantitative reverse transcriptase PCR (QRT-PCR). YAP1 protein expression was measured by western blotting. Cell viability was measured by MTT assay. Cell apoptosis was detected by flow cytometry. Luciferase reporter assay was used to confirm the relationship between ZEB1-AS1, miR-205, and YAP1.

Results

LncRNA ZEB1-AS1 and YAP1 was upregulated in CRC tissues. The expression of YAP1 was positively correlated with ZEB1-AS1. Knockdown of ZEB1-AS1 inhibited cell viability and induced apoptosis in CRC cell line SW480 and HCT116 which could be reversed by overexpression of YAP1. ZEB1-AS1 targeted and regulated miR-205 which could directly bind to YAP1. Meanwhile, ZEB1-AS1 regulated the expression of YAP1 via modulating miR-205.

Conclusion

Long non-coding RNA ZEB1-AS1 silencing could inhibit cell proliferation and induce apoptosis of colorectal cancer via regulating miR-205 and YAP1.

The prognostic value of YAP1 on clinical outcomes in human cancers

Background: As an important downstream factor in the Hippo pathway, yes-associated protein 1(YAP1) has been detected to be elevated in various cancers and demonstrated to play a role in tumor development. Therefore, we evaluated by a meta-analysis the prognostic value of YAP1 in cancer patients.

Results: Sixty-eight studies with 8631 patients were identified. The results indicated that YAP1 overexpression predicted unfavorable patient prognosis in studies with overall survival (OS) (HR=1.76, 95%CI: 1.50-2.06, p<0.001) and disease-free survival (DFS) (HR=1.39, 95%CI: 1.22-1.59, p<0.001), as well as in studies with recurrence-free survival (RFS) (HR=2.38, 95%CI: 1.73-3.27, p<0.001), and disease-specific survival (DSS) (HR=2.04, 95%CI: 1.55-2.70, p<0.001). Meanwhile, YAP1 overexpression was also observed to be significantly associated with worse OS in GEPIA (HR=1.2, p<0.001).

Conclusions: Overexpression of YAP1 showed great association with poorer prognosis in patients with various cancers, particularly liver cancer. Therefore, YAP1 might be an important prognostic marker and a novel target of cancer therapy.

Methods: We searched for potential publications in several online databases and retrieved relevant data. Overall and subgroup analyses were performed. Begg’s and Egger’s tests were used to assess publication bias. Online dataset GEPIA was used to generate the survival curves and verify the prognostic role of YAP1 in patients with tumors.

LINC00958-MYC positive feedback loop modulates resistance of head and neck squamous cell carcinoma cells to chemo- and radiotherapy in vitro

Background

Aberrant long non-coding RNA (lncRNA) expression contributes cancer development and resistance to therapy. This study first assessed expression of lncRNA LINC00958 in a variety of human cancers using GEPIA database data and then associated it with prognosis of head and neck squamous cell carcinoma (HNSCC) and investigated LINC00958 interaction with c-Myc and the c-Myc-related gene interplay in HNSCC cells.

Materials and methods

A cohort of 48 HNSCC vs normal tissues was collected for qRT-PCR analysis of LINC00958 and c-Myc expression and statistical analyses. HNSCC cell lines were subjected to transfection with LINC00958 and c-Myc siRNAs or cDNA and their negative control siRNA or empty vector for qRT-PCR, Western blot, cell viability, colony formation, luciferase reporter, chromatin immunoprecipitation, and RNA immunoprecipitation assays.

Results

The data showed that LINC00958 expression was upregulated in HNSCC tissues and cell lines, upregulation of which was associated with poor tumor differentiation, advanced tumor stage, and shorter overall survival of patients. In vitro, LINC00958 expression induced HNSCC cell viability and colony formation, whereas knockdown of LINC00958 expression enhanced HNSCC cell sensitivity to ionizing radiation and cisplatin treatment. Mechanistically, LINC00958 is a direct target of c-Myc and can enhance the transcriptional activity of c-Myc, thus to form a positive feedback gene network in HNSCC cells, and in turn to modulate HNSCC cell resistance to chemo- and radiotherapy.

Conclusion

This study demonstrated the LINC00958 interplay with c-Myc as a feedback loop facilitated HNSCC development and resistance to chemo- and radiotherapy. Targeting of such a network could be further evaluated as a novel therapeutic strategy for HNSCC patients.

Yes-Associated Protein 1 as a Novel Prognostic Biomarker for Gastrointestinal Cancer: A Meta-Analysis

Background

Yes-associated protein 1 (YAP1) is an effector of Hippo pathway, which plays a significant role in cell proliferation and tumor progression. The relationship between YAP1 and gastrointestinal cancer has been explored in many previous studies. We conducted a meta-analysis to explore the prognostic effect of YAP1 in patients with gastrointestinal cancer.

Methods

A systematic search was performed through the PubMed, Web of Science, Embase, and Cochrane library databases to collect eligible studies. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to evaluate the relationship between YAP1 expression and gastrointestinal cancer clinical outcomes.

Results

A total of 2941 patients from 18 studies were enrolled. The results showed that elevated YAP1 expression predicted a poor prognosis in gastrointestinal cancer (HR = 1.56; 95% CI: 1.29-1.89; P < 0.001). Subgroup analyses indicated significant association between YAP1 overexpression and shorter OS of patients with esophageal squamous cell carcinoma (HR = 1.85; 95% CI: 1.25-2.73; P = 0.002), gastric cancer (HR = 1.41,95% CI: 1.02-1.95; P = 0.037), and colorectal cancer (pooled HR = 1.75; 95% CI: 1.42-2.15; P < 0.001). However, YAP1 expression did not affect DFS of patients with gastrointestinal cancer (pooled HR = 1.33; 95% CI: 0.95-1.88; P = 0.101).

Conclusion

Elevated YAP1 expression in patients with gastrointestinal cancer might be related to shorter OS. YAP1 protein could serve as a potential predictor of poor prognosis in gastrointestinal cancer.

Hippo pathway affects survival of cancer patients: extensive analysis of TCGA data and review of literature

The disruption of the Hippo pathway occurs in many cancer types and is associated with cancer progression. Herein, we investigated the impact of 32 Hippo genes on overall survival (OS) of cancer patients, by both analysing data from The Cancer Genome Atlas (TCGA) and reviewing the related literature. mRNA and protein expression data of all solid tumors except pure sarcomas were downloaded from TCGA database. Thirty-two Hippo genes were considered; for each gene, patients were dichotomized based on median expression value. Survival analyses were performed to identify independent predictors, taking into account the main clinical-pathological features affecting OS. Finally, independent predictors were correlated with YAP1 oncoprotein expression. At least one of the Hippo genes is an independent prognostic factor in 12 out of 13 considered tumor datasets. mRNA levels of the independent predictors coherently correlate with YAP1 in glioma, kidney renal clear cell, head and neck, and bladder cancer. Moreover, literature data revealed the association between YAP1 levels and OS in gastric, colorectal, hepatocellular, pancreatic, and lung cancer. Herein, we identified cancers in which Hippo pathway affects OS; these cancers should be candidates for YAP1 inhibitors development and testing.