Down-regulation of long non-coding RNA ESCCAL_1 inhibits tumor growth of esophageal squamous cell carcinoma in a xenograft mouse model

Long non-coding RNA ESCCAL-1/miR-590/LRP6 signaling pathway participates in the progression of esophageal squamous cell carcinoma

BACKGROUND

Long non-coding RNAs (lncRNAs) have critical functions within esophageal squamous cell carcinoma (ESCC). However, the function and mechanism underlying ESCC-associated lncRNA-1 (ESCCAL-1) in ESCC tumorigenesis have not been well clarified.

METHODS

ESCCAL-1, miR-590 and LRP6 were quantified using qRT-PCR. Cell viability, migration and invasion abilities were measured using CCK-8 assay and transwell assays. The protein pression was determined with western blot assay. The xenograft model assays were used to examine the impact of ESCCAL-1 on tumorigenic effect in vivo. Direct relationships among ESCCAL-1, miR-590 and LRP6 were confirmed using dual-luciferase reporter assays.

RESULTS

The present work discovered the ESCCAL-1 up-regulation within ESCC. Furthermore, ESCCAL-1 was found to interact with miR-590 and consequently restrict its expression. Functionally, knocking down ESCCAL-1 or over-expressing miR-590 hindered ESCC cell growth, invasion, and migration in vitro. Moreover, inhibition of miR-590 could reverse the effect of knockdown of ESCCAL-1 on cells. Importantly, it was confirmed that LRP6 was miR-590's downstream target and LRP6 over-expression also partly abolished the role of miR-590 overexpression in ESCC cells.

CONCLUSION

We have uncovered a novel regulatory network comprising aberrant interaction of ESCCAL-1/miR-590/LRP6 participated in ESCC progression.

A Pleiotropic Role of Long Non-Coding RNAs in the Modulation of Wnt/β-Catenin and PI3K/Akt/mTOR Signaling Pathways in Esophageal Squamous Cell Carcinoma: Implication in Chemotherapeutic Drug Response

Despite the availability of modern techniques for the treatment of esophageal squamous cell carcinoma (ESCC), tumor recurrence and metastasis are significant challenges in clinical management. Thus, ESCC possesses a poor prognosis and low five-year overall survival rate. Notably, the origin and recurrence of the cancer phenotype are under the control of complex cancer-related signaling pathways. In this review, we provide comprehensive knowledge about long non-coding RNAs (lncRNAs) related to Wnt/β-catenin and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway in ESCC and its implications in hindering the efficacy of chemotherapeutic drugs. We observed that a pool of lncRNAs, such as HERES, TUG1, and UCA1, associated with ESCC, directly or indirectly targets various molecules of the Wnt/β-catenin pathway and facilitates the manifestation of multiple cancer phenotypes, including proliferation, metastasis, relapse, and resistance to anticancer treatment. Additionally, several lncRNAs, such as HCP5 and PTCSC1, modulate PI3K/Akt/mTOR pathways during the ESCC pathogenesis. Furthermore, a few lncRNAs, such as AFAP1-AS1 and LINC01014, block the efficiency of chemotherapeutic drugs, including cisplatin, 5-fluorouracil, paclitaxel, and gefitinib, used for ESCC treatment. Therefore, this review may help in designing a better therapeutic strategy for ESCC patients.

ESCCAL-1 promotes cell-cycle progression by interacting with and stabilizing galectin-1 in esophageal squamous cell carcinoma

Long non-coding RNAs (LncRNAs) play important roles in the development of human esophageal squamous cell carcinoma (ESCC). Our previous studies have shown that knockdown of LncRNA ESCCAL-1 expression inhibits the growth of ESCC cells, but the mechanisms remain largely unknown. In this study, we show that over-expression of ESCCAL-1 promotes ESCC cell proliferation and cell-cycle progression by blocking ubiquitin-mediated degradation of an oncoprotein galectin-1 (Gal-1). Multiple LncRNA expression datasets as well as our own data together reveal that ESCCAL-1 is evidently up-regulated in ESCC tissues and exhibits promising diagnostic value. Over-expression of ESCCAL-1 augmented ESCC cell proliferation and cell-cycle progression, whereas down-regulation of ESCCAL-1 resulted in the opposite effects. Mechanistically, LncRNA ESCCAL-1 directly binds to Gal-1 and positively regulates its protein level without affecting its mRNA level. Up-regulation of Gal-1 facilitated ESCC cell proliferation and cell-cycle progress. Knockdown of Gal-1 mitigated the effects of ESCCAL-1-mediated high cellular proliferation, NF-κB signaling activation and tumorigenicity of ESCC cells. Thus, our findings provide novel insight into the mechanism by which ESCCAL-1 facilitates ESCC tumorigenesis and cell-cycle progression by interacting with and stabilizing Gal-1 protein, suggesting a potential therapeutic target for ESCC.

Downregulation of long non-coding RNA LOC101928477 correlates with tumor progression by regulating the epithelial-mesenchymal transition in esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest malignancies. There is a growing body of evidence showing that long non‐coding RNAs (lncRNAs) play critical roles in ESCC oncogenesis. The present study aimed to explore the role of LOC101928477, a newly discovered lncRNA, in the development and metastasis of ESCC.

Methods

In this study, real‐time PCR, western blotting, cell counting kit‐8 (CCK‐8), flow cytometry, colony formation, wound healing, transwell migration/invasion assay, immunofluorescence, and immunohistochemistry were used. We also applied an in situ xenograft mouse model and a lung metastasis mouse model to verify our findings.

Results

We determined that LOC101928477 expression was inhibited in ESCC tissue and ESCC cell lines when compared with controls. Moreover, forced expression of LOC101928477 effectively inhibited ESCC cell proliferation, colony formation, migration, and invasion via suppression of epithelial‐mesenchymal transition (EMT). Furthermore, LOC101928477 overexpression inhibited in situ tumor growth and lung metastasis in a mouse model.

Conclusions

Together, our results suggested that LOC101928477 could be a novel suppressor gene involved in ESCC progression.

Long non-coding RNA ESCCAL-1 promotes esophageal squamous cell carcinoma by down regulating the negative regulator of APOBEC3G

The expression of lncRNA ESCCAL-1 is upregulated in esophageal squamous cell carcinoma (ESCC). However, the molecular pathways regulated by ESCCAL-1 in esophageal cancer remain obscure. We found that high expression of the lncRNA ESCCAL-1 in human ESCC tumors correlated with worse clinicopathologic features. Furthermore, depletion of ESCCAL-1 in ESCC models inhibited the cellular processes associated with malignancy, including proliferation, migration and invasion, resistance to apoptosis, and impaired tumor growth in mice. Using a combinatorial approach, we discovered that ESCCAL-1 regulates malignant phenotypes in ESCC by acting as a molecular sponge for miR-590-3p. This interaction prevents miR-590-3p from suppressing APOBEC3G expression. Increased APOBEC3G was also a biomarker of worse clinicopathologic features in human ESCC tumors. Depletion of ESSCAL-1 or APOBEC3G, or overexpression of miR-590-3p resulted in increased apoptosis due to downregulation of the PI3K/Akt signaling. This study demonstrates that the lncRNA ESCCAL-1 promotes malignant features of ESCC by relieving the inhibitory effect of miR-590-3p on APOBEC3G expression and identifies potential biomarkers or therapeutic targets to improve ESCC treatment outcomes.

lncRNA KLF3-AS1 Suppresses Cell Migration and Invasion in ESCC by Impairing miR-185-5p-Targeted KLF3 Inhibition

Esophageal squamous cell carcinoma (ESCC) is a common cancer occurring in males and females worldwide. Accumulating evidence continues to highlight the crucial roles of long non-coding RNAs (lncRNAs) in the process of tumorigenesis. However, the regulatory mechanism of lncRNAs in ESCC remains unclear. The aim of this study is to elucidate the role of lncRNA Krüppel-like factor 3 antisense RNA 1 (KLF3-AS1) in ESCC by regulating miR-185-5p and KLF3. Initially, ESCC cell spheres with stem cell-like properties were prepared by suspension culture, and subsequently characterized by assessing colony formation ability and stem cell markers. LncRNA KLF3-AS1 was found to be poorly expressed in ESCC and could upregulate the expression of KLF3 by binding to miR-185-5p. lncRNA KLF3-AS1 upregulation was observed to inhibit miR-185-5p, thereby contributing to decreased expression of SOX2 and Oct4 (octamer-binding transcription factor 4). Furthermore, enhancement of lncRNA KLF3-AS1 resulted in reduced colony formation ability, cell invasion and migration, and tumor volume in vivo while promoting cell apoptosis in ESCC through downregulation of miR-185-5p. Collectively, this study indicated that lncRNA KLF3-AS1 inhibited ESCC cell invasion and migration by impairing miR-185-5p-mediated inhibition of KLF3, highlighting a promising novel potential target for ESCC treatment.

MicroRNA-134 prevents the progression of esophageal squamous cell carcinoma via the PLXNA1-mediated MAPK signalling pathway

BACKGROUND

MicroRNAs (miRNAs) are involved in oncogenesis of esophageal squamous cell carcinoma (ESCC). miR-134 is reported to have a tumour-suppressive role but its role in ESCC is not known. The present study was designed to examine whether miR-134 inhibits ESCC development and further explored relevant underlying mechanisms.

METHODS

Differentially expressed genes related to ESCC were identified from microarray gene expression profiles. Immunohistochemical staining and RT-qRCR assays identified elevated PLXNA1 expression levels and low miR-134. The relationship between miR-134 and PLXNA1 was predicted and further verified by a dual-luciferase reporter assay. The expression levels of miR-134 and PLXNA1 in ESCC cells were modified by miR-134 mimic/inhibitor and siRNA against PLXNA1, respectively. Thereafter, the expression of MAPK signalling pathway-related proteins, as well as the viability, migration, invasion, cell cycle and cell apoptosis of ESCC cells was investigated.

FINDINGS

The results showed that miR-134 could block the MAPK signalling pathway by downregulating PLXNA1. When miR-134 was overexpressed or PLXNA1 was silenced, cell apoptosis was enhanced, the cell cycle was retarded, and the cell proliferation, migration and invasion were suppressed. In vivo experiments confirmed that miR-134 overexpression or PLXNA1 silencing restrained tumour growth and lymph node metastasis.

INTERPRETATION

These findings demonstrate that cancer cell proliferation, migration, invasion, and tumour metastasis of ESCC can be suppressed by overexpression of miR-134 through downregulating PLXNA1, which subsequently blocks the MAPK signalling pathway. These results provide new potential targets and strategies for the treatment of ESCC.

FAK alleviates radiation-induced rectal injury by decreasing apoptosis

Radiation-induced rectal injury is closely related with radiotherapy efficiency. Here, we investigated the effect of focal adhesion kinase (FAK) in radiation-induced rectal injury. Peripheral blood samples of patients with rectal cancer were collected prior to radiotherapy. Differentially expressed genes and copy number variations (CNVs) were analyzed by microarray analysis. The CTCAE v3.0 toxicity grades were used to assess acute rectal injury. The radiosensitivity of human intestinal epithelial crypt (HIEC) cells were assayed by colony formation, mitochondrial membrane potential, flow cytometry and western blotting. The rectums of C57BL/6 mice were X-irradiated locally with a single dose of 15 Gy. The effect of FAK on radiation-induced injury was investigated by hematoxylin-eosin (H&E) staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), immunohistochemistry (IHC) and quantitative real-time PCR (qRT-PCR). FAK mRNA level was inversely correlated with rectal injury severity in patient samples. A CNV amplification located on chromosome 8 was closely related with FAK. Further functional assays revealed increased levels of γH2AX expression and apoptosis-related proteins in FAK-silenced HIEC cells. The ratio of TUNEL, cl-caspase-3, cyto-c and bax/bcl-2 expression in the rectum mucosa treated with a FAK inhibitor increased significantly. These results demonstrated that FAK reduced radiation-induced rectal injury by decreasing apoptosis.