Downregulation of YAP inhibits proliferation and induces apoptosis in Eca-109 cells

Asiaticoside inhibits breast cancer progression and tumor angiogenesis via YAP1/VEGFA signal pathway

Objective

Breast cancer poses a major health risk to millions of females globally. Asiaticoside (AC) is a naturally occurring compound derived from Centella asiatica, a widely used medicinal plant in the oriental countries and has potential antitumor properties. The primary aim of this study was to investigate the anti-cancer effects of synthesized AC at the cellular level and assess its ability to inhibit tumor growth and angiogenesis in breast cancer.

Methods

The proliferative capacities of MCF-7 and MDA-MB-231 cells were determined using CCK-8 assay. To analyze invasion and migration, Transwell assays were conducted on the same cell lines. Additionally, apoptosis was analyzed in vitro using flow cytometry. Real-time RT-PCR was used to examine mRNA expression, and Western-blotting assay was employed to examine protein expression. Subcutaneous injection of MDA-MB-231 cells into female BALB/c nude mice was followed by treatment with AC to study its anti-tumor effects in vivo.

Results

AC treatment reduced cell proliferation and triggered apoptosis in MCF-7 and MDA-MB-231 cells. The invasive and pro-angiogenesis ability were also impaired upon AC treatment. AC administration also impeded the tumor growth and tumor-associated angiogenesis of MDA-MB-231 cells in nude mice, which was accompanied by the decreased levels of YAP1 and VEGFA.

Conclusion

Taken together, our results demonstrated the anti-cancer activity of AC in breast cancer. AC is able to suppress the malignancy of breast cancercells via YAP1/VEGFA signal pathway.

Chaetocin exhibits anticancer effects in esophageal squamous cell carcinoma via activation of Hippo pathway

Dysfunction of the Hippo pathway is common in esophageal squamous carcinoma (ESCC). Chaetocin, a small molecular compound isolated from the marine fungus, exhibits potent anticancer effects. However, the anticancer effects of chaetocin on ESCC and its potential relationship to Hippo pathway remain unclear. Here, we demonstrated that chaetocin dramatically inhibited the proliferation in ESCC cells by causing cycle arrest in the M phase and activating the caspase-dependent apoptosis signaling pathway in vitro, and we also found that chaetocin induced the accumulation cellular reactive oxygen species (ROS). The RNA-seq analysis indicated that the Hippo pathway is one of the most enriched pathways after chaetocin treatment. We further revealed that chaetocin triggered the activation of Hippo pathway in ESCC cells, which is characterized by elevated phosphorylation levels of almost all core proteins in Hippo pathway, such as MST1 (Thr183), MST2 (Thr180), MOB1 (Thr35), LAST1 (Thr1079 and Ser909) and YAP (Ser127), ultimately leading to decreased nuclear translocation of YAP. Moreover, the MST1/2 inhibitor XMU-MP-1 not only partially rescued the inhibitory effect chaetocin-induced proliferation, but also rescued the chaetocin-induced apoptosis in ESCC cells. Furthermore, in vivo results confirmed the antitumor effect of chaetocin and its relationship with Hippo pathway. Taken together, our study demonstrates that chaetocin exhibits anticancer effects in ESCC via activation of Hippo pathway. These results provide an important basis for further research of chaetocin as a potential candidate for ESCC treatment.

Emerging role of interaction between m6A and main ncRNAs in gastrointestinal (GI) cancers

As a prevalent epigenetic modification, the role of m6A has been increasingly highlighted in the alteration of numerous RNAs implicated with multiple biological processes, such as formation, export, translation, and degradation. With further the understanding of m6A, accumulating evidence shows that m6A modification similarly affects metabolic process of non-coding genes. But the specifical interplay of m6A and ncRNAs (non-coding RNAs) in gastrointestinal cancers still lacks complete discussion. Thus, we analyzed and summarized how ncRNAs affect the regulators of m6A and by what means the expression of ncRNAs is altered via m6A in gastrointestinal cancers. We focused on the effect of the interaction of m6A and ncRNAs on the molecular mechanisms of malignant behavior in gastrointestinal cancers, revealing more possibilities of ncRNAs for diagnosis and treatment in term of epigenetic modification.

N6-methyladenosine demethylase ALKBH5 suppresses malignancy of esophageal cancer by regulating microRNA biogenesis and RAI1 expression

N6-Methyladenosine (m6A) is the most prevalent epigenetic RNA modification and is vital in regulating malignancies. The roles of m6A modifiers on noncoding RNAs have not been fully investigated in esophageal cancer. By screening all m6A modifiers, ALKBH5 was the most potent member related to patient outcomes and suppressing esophageal cancer malignancy in cell and animal models. It demethylated pri-miR-194-2 and inhibited miR-194-2 biogenesis through an m6A/DGCR8-dependent manner. RAI1, previously considered as a circadian clock transcriptional regulator, was the main target of miR-194-2. It enhanced transcription of Hippo pathway upstream genes by binding to their 3'UTR and suppressed YAP/TAZ nuclear translocation. The ALKBH5/miR-194-2/RAI1 axis was also validated in clinical samples. In addition, the increased malignancy by low ALKBH5 was abolished by the YAP inhibitor verteporfin. Our findings uncover a critical role of ALKBH5 in miRNAs biogenesis and provide novel insight for developing treatment strategies in esophageal cancer.

Mutant p53 regulates Survivin to foster lung metastasis

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal cancers worldwide and evolves often to lung metastasis. P53R175H (homologous to Trp53R172H in mice) is a common hot spot mutation. How metastasis is regulated by p53R175H in ESCC remains to be investigated. To investigate p53R175H-mediated molecular mechanisms, we used a carcinogen-induced approach in Trp53R172H/- mice to model ESCC. In the primary Trp53R172H/- tumor cell lines, we depleted Trp53R172H (shTrp53) and observed a marked reduction in cell invasion in vitro and lung metastasis burden in a tail-vein injection model in comparing isogenic cells (shCtrl). Furthermore, we performed bulk RNA-seq to compare gene expression profiles of metastatic and primary shCtrl and shTrp53 cells. We identified the YAP-BIRC5 axis as a potential mediator of Trp53R172H -mediated metastasis. We demonstrate that expression of Survivin, an antiapoptotic protein encoded by BIRC5, increases in the presence of Trp53R172H Furthermore, depletion of Survivin specifically decreases Trp53R172H-driven lung metastasis. Mechanistically, Trp53R172H but not wild-type Trp53, binds with YAP in ESCC cells, suggesting their cooperation to induce Survivin expression. Furthermore, Survivin high expression level is associated with increased metastasis in several GI cancers. Taken together, this study unravels new insights into how mutant p53 mediates metastasis.

Corosolic Acid Inhibits Cancer Progress Through Inactivating YAP in Hepatocellular Carcinoma

Chemotherapy is critical for the treatment of hepatocellular carcinoma (HCC). Despite the proapoptotic effects of corosolic acid (CA) treatment, its underlying mechanism is not completely clear. The aim of this study was to determine the molecular mechanism of CA in HCC treatment. MTT assay was used to determine the IC₅₀ of CA. Immunoprecipitation and immunofluorescence were used to detect the interaction and subcellular localization of Yes-associated protein (YAP) and mouse double minute 2 (MDM2). In addition, in vivo xenotransplantation was performed to assess the effects of CA, YAP, and MDM2 on tumorigenesis. The IC₅₀ of CA was about 40 μM in different HCC cell lines, and CA decreased YAP expression by reducing its stability and increasing its ubiquitination. CA treatment and MDM2 overexpression significantly decreased the crosstalk between YAP and cAMP-responsive element-binding protein (CREB), TEA domain transcription factor (TEAD), and Runt-related transcription factor 2 (Runx2). CA stimulation promoted the translocation of YAP and MDM2 from the nucleus to the cytoplasm and increased their binding. In addition, CA treatment obviously reduced tumorigenesis, whereas this effect was abolished when cells were transfected with sh-MDM2 or Vector-YAP. The present study uncovered that CA induced cancer progress repression through translocating YAP from the nucleus in HCC, which might provide a new therapeutic target for HCC.

Yes-associated protein (YAP) predicts poor prognosis and regulates progression of esophageal squamous cell cancer through epithelial-mesenchymal transition

The impact of yes-associated protein (YAP) on the prognosis of patients with esophageal squamous cell cancer (ESCC) and its mechanism of action has seldom been reported. In the present study, the role of YAP on the prognosis of patients with ESCC and the mechanism of action of YAP in promoting the progression of ESCC was investigated. Tumor tissue samples from patients with ESCC were collected and the level of YAP expression was detected using immunohistochemical staining. In addition, YAP was knocked-down in ESCC cell lines and the effects on cell migration and invasion were examined. The expression levels of vimentin, N-cadherin, and E-cadherin were further investigated to examine the association between YAP and epithelial-mesenchymal transition (EMT). Results showed that overexpression of YAP was associated with larger lymph node metastasis and poor disease-free survival and overall survival. Compared with patients in early stage ESCC, the association was more significant in patients with late stage ESCC. Univariate and multivariate analyses further indicated that YAP expression could be an independent prognostic factor for ESCC. Downregulation of YAP inhibited cell migration and invasion. Western blot analysis showed that when YAP was knocked down, expression levels of vimentin and N-cadherin were reduced, whereas that of E-cadherin was increased. In conclusion, the results indicates that YAP expression level could be a novel marker for predicting the prognosis of patients with ESCC, and YAP-promoted tumor migration and invasion might be through EMT in ESCC.

Folic Acid Has a Protective Effect on Retinal Vascular Endothelial Cells against High Glucose

Diabetic retinopathy (DR) is a severe complication of diabetes, which seriously affects the life quality of patients. Because of the damage caused by DR, there is an urgent need to develop effective drugs. Folic acid, a water-soluble vitamin, is one of the vitamin B complexes. Folic acid is widely found in the meat and vegetables. In the clinic, low folic acid levels in the body may have a certain correlation with DR. However, there is no relevant basic research proving a relationship between folic acid levels and DR. The purpose of this study was therefore to investigate whether folic acid has a protective effect on the retinal vascular endothelial cells against high glucose levels. Moreover, the molecular mechanism of action of folic acid was further explored. The results showed that folic acid significantly suppressed the cell viability, tube length, migrated cells and the percentage of BrdU⁺ cells compared with the high glucose group. Moreover, folic acid decreased the mRNA expression of TEAD1 and the protein expression of TEAD1 and YAP1. These findings indicate that folic acid can protect retinal vascular endothelial cells from high glucose-induced injury by regulating the proteins in the Hippo signaling pathway.