The role of long non-coding RNA BCAR4 in human cancers

BCAR4 facilitates trastuzumab resistance and EMT in breast cancer via sponging miR-665 and interacting with YAP1

Breast cancer antiestrogen resistance 4 (BCAR4) has been suggested that can modulate cell behavior, resulting in tumorigenesis and chemoresistance. However, the underlying mechanisms of BCAR4 in trastuzumab resistance (TR) is still elusive. Here, we explored the function and the underlying mechanism of BCAR4 involving in TR. We found that BCAR4 is significantly upregulated in trastuzumab-resistant BC cells. Knockdown of BCAR4 could sensitize the BC cells to trastuzumab and suppress epithelial-mesenchymal transition (EMT). Mechanically, BCAR4 promotes yes-associated protein 1 (YAP1) expression by competitively sponging miR-665, to activated TGF-β signaling. Reciprocally, YAP1 could occupy the BCAR4 promoter to enhance its transcription, suggesting that there exists a positive feedback regulation between YAP1 and BCAR4. Targeting the BCAR4/miR-665/YAP1 axis may provide a novel insight of therapeutic approaches for TR in BC.

Epigenetic Abnormalities in Chondrosarcoma

In recent years, our understanding of the epigenetic mechanisms involved in tumor pathology has improved greatly. DNA and histone modifications, such as methylation, demethylation, acetylation, and deacetylation, can lead to the up-regulation of oncogenic genes, as well as the suppression of tumor suppressor genes. Gene expression can also be modified on a post-transcriptional level by microRNAs that contribute to carcinogenesis. The role of these modifications has been already described in many tumors, e.g., colorectal, breast, and prostate cancers. These mechanisms have also begun to be investigated in less common tumors, such as sarcomas. Chondrosarcoma (CS) is a rare type of tumor that belongs to sarcomas and is the second most common malignant bone tumor after osteosarcoma. Due to unknown pathogenesis and resistance to chemo- and radiotherapies of these tumors, there is a need to develop new potential therapies against CS. In this review, we summarize current knowledge on the influence of epigenetic alterations in the pathogenesis of CS by discussing potential candidates for future therapies. We also emphasize ongoing clinical trials that use drugs targeting epigenetic modifications in CS treatment.

The role of ubiquitin signaling pathway on liver regeneration in rats

The ubiquitin signalling pathway is a large system associated with numerous intracellular mechanisms. However, its function in the liver regeneration process remains unknown. This particular study investigates the intracellular effect mechanisms of the ubiquitin signalling pathway. It also determines the differences in the expression of 88 genes belonging to the ubiquitin pathway using the RT-PCR array method. To conduct this research, three genes-that differed in the expression analysis were selected. Moreover, their proteins were analysed by western blot analysis while using Ki67 immunohistochemical analysis that determines proliferation rates by hour. It was determined that BRCA1 and BARD1, which are effective in DNA repair, play an active role at PH24. Similarly, Ube2t expression, which belongs to the Fanconi anaemia pathway associated with DNA repair, was also found to be high at PH12-72 h. In addition, it was revealed that the expressions of Anapc2, Anapc11, Cdc20 belonging to the APC/C^Cdc20 complex, which participate in cell cycle regulation, differed at different hours after PH. Expression of Mul1, which is involved in mitochondrial biogenesis and mitophagy mechanisms, peaked at PH12 under the observation. Considering the Mul1 gene expression difference, MUL1-mediated mitophagy and mitochondrial fission mechanism may be associated with liver regeneration. It was also determined that PARKIN-mediated mitophagy mechanisms are not active in 0-72 h of liver regeneration since PARKIN expression did not show a significant change in PH groups.

Identification of a seven-lncRNAs panel that serves as a prognosis predictor and contributes to the malignant progression of laryngeal squamous cell carcinoma

Background

Laryngeal squamous cell carcinoma (LSCC) is one of the most frequent head and neck cancers worldwide. Long non-coding RNAs (lncRNAs) play a critical role in tumorigenesis. However, the clinical significance of lncRNAs in LSCC remains largely unknown.

Methods

In this study, transcriptome sequencing was performed on 107 LSCC and paired adjacent normal mucosa (ANM) tissues. Furthermore, RNA expression and clinical data of 111 LSCC samples were obtained from The Cancer Genome Atlas (TCGA) database. Bioinformatics analysis were performed to construct a model for predicting the overall survival (OS) of LSCC patients. Moreover, we investigated the roles of lncRNAs in LSCC cells through loss-of-function experiments.

Results

A seven-lncRNAs panel including ENSG00000233397, BARX1-DT, LSAMP-AS1, HOXB-AS4, MNX1-AS1, LINC01385, and LINC02893 was identified. The Kaplan-Meier analysis demonstrated that the seven-lncRNAs panel was significantly associated with OS (HR:6.21 [3.27-11.81], p-value<0.0001), disease-specific survival (DSS) (HR:4.34 [1.83-10.26], p-value=0.0008), and progression-free interval (PFI) (HR:3.78 [1.92-7.43], p-value=0.0001). ROC curves showed the seven-lncRNAs panel predicts OS with good specificity and sensitivity. Separately silencing the seven lncRNAs inhibited the proliferation, migration, and invasion capacity of LSCC cells.

Conclusion

Collectively, this seven-lncRNAs panel is a promising signature for predicting the prognosis of LSCC patients, and these lncRNAs could serve as potential targets for LSCC treatment.

Long non-coding RNA CCAT2 drives the growth of laryngeal squamous cell carcinoma via regulating YAP activity

Emerging evidence suggests that long non-coding RNA (lncRNA) is closely associated with numerous human diseases, including cancer. However, the functional relevance of lncRNA in human laryngeal squamous cell carcinoma (LSCC) is largely unknown. In the current study, we described CCAT2, a previously unappreciated oncogenic lncRNA in LSCC. CCAT2 was significantly upregulated in human LSCC tissue and serum samples, associated with larger tumor volume, higher clinical stage, and poorer differentiation status. Lentivirus-mediated CCAT2 knockdown notably repressed the cell viability, colony formation, and DNA synthesis rate of LSCC. Screening of transcription factors revealed that YAP/TEAD activity was affected by CCAT2 in LSCC cells. Further, CCAT2 directly binds to YAP protein and blocks the phosphorylation of YAP induced by LATS1, resulting in the nuclear translocation of YAP and the activation of YAP oncogenic targets, such as CTGF, CYR61 and AMOTL2. Importantly, we also confirmed the regulation of CCAT2 on YAP activity in vivo based on nude mice model. Altogether, we identified a novel lncRNA that controls YAP nucleocytoplasmic shuttling and promotes LSCC cell proliferation. Given the importance of YAP in tumorigenesis and progression, our results provide insights to intervene LSCC by targeting the CCAT2/YAP axis.