Metadherin regulates actin cytoskeletal remodeling and enhances human gastric cancer metastasis via epithelial-mesenchymal transition

Cancer fitness genes: emerging therapeutic targets for metastasis

Development of cancer therapeutics has traditionally focused on targeting driver oncogenes. Such an approach is limited by toxicity to normal tissues and treatment resistance. A class of 'cancer fitness genes' with crucial roles in metastasis have been identified. Elevated or altered activities of these genes do not directly cause cancer; instead, they relieve the stresses that tumor cells encounter and help them adapt to a changing microenvironment, thus facilitating tumor progression and metastasis. Importantly, as normal cells do not experience high levels of stress under physiological conditions, targeting cancer fitness genes is less likely to cause toxicity to noncancerous tissues. Here, we summarize the key features and function of cancer fitness genes and discuss their therapeutic potential.

METTL1 promotes neuroblastoma development through m7G tRNA modification and selective oncogenic gene translation

Background

Neuroblastoma (NBL) is the most common extra-cranial solid tumour in childhood, with prognosis ranging from spontaneous remission to high risk for rapid and fatal progression. Despite existing therapy approaches, the 5-year event-free survival (EFS) for patients with advanced NBL remains below 30%, emphasizing urgent necessary for novel therapeutic strategies. Studies have shown that epigenetic disorders play an essential role in the pathogenesis of NBL. However, the function and mechanism of N7-methylguanosine (m⁷G) methyltransferase in NBL remains unknown.

Methods

The expression levels of m⁷G tRNA methyltransferase Methyltransferase-like 1 (METTL1) were analyzed by querying the Gene Expression Omnibus (GEO) database and further confirmed by immunohistochemistry (IHC) assay. Kaplan-Meier, univariate and multivariate cox hazard analysis were performed to reveal the prognostic role of METTL1. Cell function assays were performed to evaluate how METTL1 works in proliferation, apoptosis and migration in cell lines and xenograft mouse models. The role of METTL1 on mRNA translation activity of NBL cells was measured using puromycin intake assay and polysome profiling assay. The m⁷G modified tRNAs were identified by tRNA reduction and cleavage sequencing (TRAC-seq). Ribosome nascent-chain complex-bound mRNA sequencing (RNC-seq) was utilized to identify the variation of gene translation efficiency (TE). Analyzed the codon frequency decoded by m⁷G tRNA to clarify the translation regulation and mechanism of m⁷G modification in NBL.

Results

This study found that METTL1 were significantly up-regulated in advanced NBL, which acted as an independent risk factor and predicted poor prognosis. Further in NBL cell lines and BALB/c-nu female mice, we found METTL1 played a crucial role in promoting NBL progression. Furthermore, m⁷G profiling and translation analysis revealed downregulation of METTL1 would inhibit puromycin intake efficiency of NBL cells, indicating that METTL1 did count crucially in regulation of NBL cell translation. With all tRNAs with m⁷G modification identified in NBL cells, knockdown of METTL1 would significantly reduce the levels of both m⁷G modification and m⁷G tRNAs expressions. Result of RNC-seq shew there were 339 overlapped genes with impaired translation in NBL cells upon METTL1 knockdown. Further analysis revealed these genes contained higher frequency of codons decoded by m⁷G-modified tRNAs and were enriched in oncogenic pathways.

Conclusion

This study revealed the critical role and mechanism of METTL1-mediated tRNA m⁷G modification in regulating NBL progression, providing new insights for developing therapeutic approaches for NBL patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-022-00414-z.

Metadherin-mediated mechanisms in human malignancies

Metadherin (MTDH) has been recognized as a novel protein that is critical for the progression of multiple types of human malignancies. Studies have reported that MTDH enhances the metastatic potential of cancer cells by regulating multiple signaling pathways. miRNAs and various tumor-related proteins have been shown to interact with MTDH, making it a potential therapeutic target as well as a biomarker in human malignancies. MTDH plays a critical role in inflammation, angiogenesis, hypoxia, epithelial-mesenchymal transition and autophagy. In this review, we present the function and mechanisms of MTDH for cancer initiation and progression.

ANLN Enhances Triple-Negative Breast Cancer Stemness Through TWIST1 and BMP2 and Promotes its Spheroid Growth

ANLN is frequently upregulated in triple-negative breast cancer (TNBC) and its high expression in tumors are significantly associated with poor survival and recurrence, thereby it has been proposed to function as a prognostic marker for breast cancer. However, the specific function and molecular mechanisms by which ANLN promotes TNBC tumorigenesis remain elusive. Using multiomic profiling, we recently uncovered ANLN as a TNBC-specific gene driven by super-enhancer. Here, by Crispr/Cas9 editing, we showed that knockout of ANLN inhibits spheroid growth of TNBC. Interestingly, its effect on cell proliferation in 2D cultures is minimal. ANLN depletion inhibits mammosphere formation and clonogenicity potently, suggesting its important function in regulating cancer stem cells (CSCs). We screened a panel of stem cell-related genes and uncovered several CSC genes regulated by ANLN. We further identify TWIST1 and BMP2 as essential genes that mediate ANLN’s function in stemness but not spheroid growth. These findings may contribute to search for effective targeted therapies to treat TNBC.

MetaDE-Based Analysis of circRNA Expression Profiles Involved in Gastric Cancer

BACKGROUND

Circular RNAs (circRNAs) could play carcinogenic roles in gastric cancer (GC) and have potential to be biomarkers for GC early diagnosis, which needs to be further excavated and supported by more evidence.

AIMS

The study aims to identify more authentic circRNA expression profiles that could function as potential biomarkers in GC.

METHODS

circRNA expression data in three microarrays were downloaded from Gene Expression Omnibus datasets. A systematic meta-analysis based on an integrated dataset pre-processed from the three microarrays was conducted to identify a panel of differentially expressed circRNAs (DEcircs) by using the metaDE package. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes term enrichment were used to note the corresponding functions of DEcircs. Quantitative real-time polymerase chain reaction was applied to verify the DEcircs expression in cancer tissues and adjacent paracancerous tissues. A GC risk-related circRNAs-miRNAs-mRNAs network was further constructed and analyzed.

RESULTS

MetaDE analysis suggested 64 DEcircs between cancer tissues and adjacent normal tissues. GO and KEGG analysis showed that the parental genes of these DEcircs were mainly associated with histone methylation, Wnt signalosome and histone methylation activity. Hsa_circ_0005927 and hsa_circ_0067934 were verified in GC tissues, and a GC risk-related network was constructed.

CONCLUSION

MetaDE-based circRNA expression profiles revealed a series of potential biomarkers involved in GC. Two circRNAs, hsa_circ_0005927 and hsa_circ_0067934, could be more authentic biomarkers for GC screening. The GC risk-related network of hsa_circ_0005927/hsa_circ_0067934 and their downstream targets will provide new genetic insights for GC research.

Long Noncoding RNA DLGAP1-AS1 Promotes the Aggressive Behavior of Gastric Cancer by Acting as a ceRNA for microRNA-628-5p and Raising Astrocyte Elevated Gene 1 Expression

Purpose

The long noncoding RNA DLGAP1 antisense RNA 1 (DLGAP1-AS1) plays well-defined roles in the malignant progression of hepatocellular carcinoma. The purpose of this study was to determine whether DLGAP1-AS1 affects the aggressive behavior of gastric cancer (GC).

Methods

DLGAP1-AS1 expression in GC tissue samples and cell lines was determined by reverse-transcription quantitative PCR. GC cell proliferation, apoptosis, migration, invasion, and tumor growth in vitro as well as in vivo were examined by the Cell Counting Kit-8 assay, flow-cytometric analysis, transwell migration and invasion assays, and xenograft model experiments, respectively.

Results

DLGAP1-AS1 was overexpressed in GC tissue samples and cell lines. Among patients with GC, the increased level of DLGAP1-AS1 correlated with tumor size, TNM stage, lymph node metastasis, distant metastasis, and shorter overall survival. The knockdown of DLGAP1-AS1 suppressed GC cell proliferation, migration, and invasion in vitro, as well as promoted cell apoptosis and hindered tumor growth in vivo. Mechanistically, DLGAP1-AS1 functioned as a competing endogenous RNA for microRNA-628-5p (miR-628-5p) in GC cells, thereby increasing the expression of the miR-628-5p target astrocyte elevated gene 1 (AEG-1). Functionally, the recovery of the miR-628-5p/AEG-1 axis output attenuated the effects of DLGAP1-AS1 knockdown in GC cells.

Conclusion

DLGAP1-AS1 is a pleiotropic oncogenic lncRNA in GC. DLGAP1-AS1 plays a pivotal part in the oncogenicity of GC in vitro and in vivo by regulating the miR-628-5p/AEG-1 axis. DLGAP1-AS1, miR-628-5p, and AEG-1 form a regulatory pathway to facilitate GC progression, suggesting this pathway as an effective target for the treatment of GC.

DLX6-AS1/miR-204-5p/OCT1 positive feedback loop promotes tumor progression and epithelial-mesenchymal transition in gastric cancer

BACKGROUND

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) participate in progression of gastric cancer (GC). Nevertheless, the function and expression level of DLX6-AS1 in GC remain unknown.

METHODS

We explored the sequencing data of DLX6-AS1 downloaded from The Cancer Genome Atlas. The expression of DLX6-AS1, miR-204-5p and OCT1 in 56 GC patients and GC cell lines was quantified by qRT-PCR and western blotting. Furthermore, we performed in vitro functional assays to assess proliferation, invasion and migration of GC cells by knockdown of DLX6-AS1. The expression level of epithelial-mesenchymal transition (EMT)-related genes was also determined by qRT-PCR and western blotting. Actin remodeling was detected by F-actin phalloidin staining. The luciferase reporter assay and chromatin immunoprecipitation assay was utilized to confirm the bioinformatic prediction. The function of the DLX6-AS1/miR-204-5p/OCT1 axis in GC proliferation was clarified by rescue assays.

RESULTS

We first demonstrated that DLX6-AS1 was upregulated in GC tissues and cell lines and was associated with T3/T4 invasion, distant metastasis and poor clinical prognosis. Further functional analysis showed that downregulation of DLX6-AS1 inhibited GC cell proliferation, migration, invasion and EMT in vitro. Mechanistic investigation indicated that DLX6-AS1 acted as a cancer-promoting competing endogenous RNA (ceRNA) by binding miR-204-5p and upregulating OCT1. Moreover, the transcription factor OCT1 was confirmed to enhance DLX6-AS1 expression by targeting the promoter region.

CONCLUSIONS

This study revealed that OCT1-induced DLX6-AS1 promoted GC progression and the EMT via the miR-204-5p/OCT1 axis, suggesting that this lncRNA might be a promising prognostic biomarker and therapeutic target for GC.

Reduction of Hip2 suppresses gastric cancer cell proliferation, migration, invasion and tumorigenesis

Background

Hip2, a ubiquitin-conjugating enzyme, has been shown to modulate the stability of cyclin B1, a cell cycle regulator. However, the function of Hip2 in gastric cancer (GC) remains largely elusive.

Methods

The expression of Hip2 in GC cell lines was analyzed by RT-qPCR, Western Blotting and Immunohistochemical Staining. shRNA was utilized to knock down the expression of Hip2. Cell growth, cell cycle, migration, invasion and tumorigenesis were performed by CCK-8, BrdU staining, flow cytometry, wound healing, transwell migration and invasion, and xenograft assay, respectively.

Results

Hip2 was highly expressed in GC cell lines and patients. High level of Hip2 indicated poor prognosis. Knockdown of Hip2 suppressed cell growth, lead to G2/M phase arrest, and reduced cell migration and invasion in vitro. Furthermore, downregulation of Hip2 inhibited tumorigenesis in vivo.

Conclusions

Elevated expression of HIP2 in GC patients suggested poor prognosis. Reduction of Hip2 suppressed GC progression, indicating that Hip2 may be a potential target for the management of GC.

Long non-coding RNA CASC19 is associated with the progression and prognosis of advanced gastric cancer

Evidence indicates that aberrantly expressed long non-coding RNAs (lncRNAs) are involved in the development and progression of advanced gastric cancer (AGC). Using RNA sequencing data and clinical information obtained from The Cancer Gene Atlas, we combined differential lncRNA expression profiling and weighted gene co-expression network analysis to identify key lncRNAs associated with AGC progression and prognosis. Cancer susceptibility 19 (CASC19) was the top hub lncRNA among the lncRNAs included in the gene module most significantly correlated with AGC’s pathological variables. CASC19 was upregulated in AGC clinical samples and was significantly associated with higher pathologic TNM stage, pathologic T stage, lymph node metastasis, and poor overall survival. Multivariable Cox analysis confirmed that CASC19 overexpression is an independent prognostic factor for overall survival. Furthermore, quantitative real-time PCR assay confirmed that CASC19 expression in four human gastric cancer cells (AGS, BGC-823, MGC-803, and HGC-27) was significantly upregulated compared with human normal gastric mucosal epithelial cell line (GES-1). Functionally, CASC19 knockdown inhibited GC cell proliferation and migration in vitro. These findings suggest that CASC19 may be a novel prognostic biomarker and a potential therapeutic target for AGC.

Metadherin: A Therapeutic Target in Multiple Cancers

Altered expression of many genes and proteins is essential for cancer development and progression. Recently, the affected expression of metadherin (MTDH), also known as AEG-1 (Astrocyte Elevated Gene 1) and Lyric, has been implicated in various aspects of cancer progression and metastasis. Elevated expression of MTDH/AEG-1 has been reported in many cancers including breast, prostate, liver, and esophageal cancers, whereas its expression is low or absent in non-malignant tissues. These expression studies suggest that MTDH may represent a potential tumor associated antigen. MTDH also regulates multiple signaling pathways including PI3K/Akt, NF-κB, Wnt/β-catenin, and MAPK which cooperate to promote the tumorigenic and metastatic potential of transformed cells. Several microRNA have also been found to be associated with the increased MTDH expression in different cancers. Increased MTDH levels were linked to the tumor chemoresistance making it an attractive novel therapeutic target. In this review, we summarize data on MTDH function in various cancers.

miR‑454‑3p suppresses cell migration and invasion by targeting CPEB1 in human glioblastoma

MicroRNAs (miRNA/miRs) serve crucial roles in the progression of human glioblastoma (GBM); however, the exact regulatory mechanisms of miRNAs in human GBM remain unclear. The present study aimed to investigate the roles of miR‑454‑3p in human GBM. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis was performed to examine the expression of miR‑454‑3p in glioma tissues and adjacent tissues. Human GBM cell lines (LN‑229, A172 and GL15) and a normal human astrocyte cells (HA1800) were used for analysis. In addition, RT‑qPCR and western blotting were applied for mRNA and protein expression analysis, respectively. The cell proliferation was measured using a Cell Counting kit‑8 assay. Furthermore, scratch and Transwell assays were employed for the analysis of cell migration and invasion. A luciferase reporter assay was used to verify the target of miR‑454‑3p. The results revealed that miR‑454‑3p was downregulated in the glioma tissues and GBM cell lines, including LN‑229, A172 and GL15. Additionally, the overexpression of miR‑454‑3p significantly suppressed the proliferation, migration and invasion of LN‑229 cells. Furthermore, cytoplasmic polyadenylation element‑binding protein 1 (CPEB1) was confirmed as a direct target of miR‑454‑3p. These findings indicated that the overexpression of miR‑454‑3p inhibited cell proliferation, migration and invasion by downregulating CPEB1. Therefore, miR‑454‑3p may act as a tumor suppressor and represent an effective therapeutic strategy in GBM.

MicroRNA-195 inhibits epithelial-mesenchymal transition via downregulating CDK4 in bladder cancer

Bladder cancer is one of the most common cancers in the world. Despite advanced development made to improve the diagnosis and therapy techniques for bladder cancer, patients always have a poor outcome based on its high potential for metastasis. MiR-195 was reported to have close relevance with the process of bladder cancer. However, the molecular mechanism of miR-195 underlying bladder cancer metastasis and epithelial-mesenchymal transition (EMT) remains unclear. The present study was done to explore the function of miR-195 on EMT and cell migration in bladder cancer. In the present study, we detected the level of miR-195 in 25 matched human bladder cancer tissues and normal adjacent tissues, as well as bladder cancer cell lines or normal cells. Additionally, we determined the effects of miR-195 on expression of CDK4, and the miR-195/CKD4 signaling cascade on cell cycle, invasion, migration, and viability. Results showed that miR-195 was down expressed in bladder cancer tissues and cell lines, which inhibited EMT, cell migration, and invasion. We identify CDK4, an early G1 cell cycle regulator, as a downstream target of miR-195. Also, we found that miR-195 could induce G1-phase arrest, inhibit cell invasion, migration, and viability through down-regulation of CDK4 expression in 5637 and BIU-87 cells. Our experimental data suggest an important role for miR-195/CDK4 in bladder tumorigenesis and provide a potential therapeutic strategy for bladder cancer.

miR-145 and miR-497 suppress TGF-β-induced epithelial-mesenchymal transition of non-small cell lung cancer by targeting MTDH

Background

MicroRNAs (miRNAs) have been reported to play crucial roles in multiple cancers including non-small cell lung cancer (NSCLC). Here, we investigated the role of miR-145 and miR-497 in TGF-β-induced epithelial–mesenchymal transition (EMT) process of NSCLC.

Methods

We performed quantitative real time PCR (qRT-PCR) to detect the expression level of miR-145 and miR-497 in NSCLC cell lines. Then in the presence/absence of TGF-β, we transfected miRNA mimics or inhibitor into A549 and H1299 cells and investigated the role of miR-145 and miR-497 in cell migration and invasion using transwell and wound-healing assay. The regulation role of miR-145 and miR-497 on Metadherin (MTDH) was determined by luciferase assay. The expression level of MTDH and EMT markers E-cadherin and vimentin were detected on mRNA and protein level.

Results

In our study, our results showed that miR-145 and miR-497 were downregulated in NSCLC cell lines. Overexpression of miR-145 and miR-497 inhibited TGF-β-induced EMT and suppressed cancer cell migration and invasion, while the opposite results were observed in cells transfected with miR-145 or miR-497 inhibitor. Moreover, the luciferase assay confirmed that miR-145 and miR-497 attenuated MTDH expression by directly binding 3′-UTR of MTDH mRNA and exert the tumor-suppression role.

Conclusions

Overall, we demonstrated that miR-145 and miR-497 functioned as EMT-suppressor in NSCLC by targeting MTDH, provided new evidence that miR-145 and miR-497 as potential therapeutic targets.

MicroRNA‑675 inhibits cell proliferation and invasion in melanoma by directly targeting metadherin

Melanoma is derived from melanocytes and accounts for ~80% of skin cancer-associated fatalities worldwide. The dysregulation of microRNAs (miRNAs/miRs) is involved in the development and progression of melanoma. Therefore, miRNAs may be novel diagnostic or prognostic biomarkers and promising therapeutic targets in the treatment of patients with melanoma. miR‑675 is differentially expressed in several types of human cancer and has important roles in the pathogenesis of several diseases. However, the expression levels and the biological roles of miR‑675 in melanoma remain unclear. Therefore, the present study aimed to assess the expression of miR‑675 in melanoma, explore the effects of miR‑675 on melanoma cells and investigate the underlying molecular mechanisms that may be involved in the actions of miR‑675. The present study indicated that miR‑675 expression was downregulated in melanoma tissues and cell lines. Functional assays demonstrated that the upregulation of miR‑675 impaired cell proliferation and invasion in melanoma. Bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis demonstrated that metadherin (MTDH) was a direct target of miR‑675 in melanoma. The MTDH levels were upregulated in melanoma tissues and inversely correlated with the miR‑675 expression. Furthermore, restored MTDH expression rescued the inhibition effects in melanoma cells caused by miR‑675 overexpression. Thus, miR‑675 may be a potential therapeutic target for melanoma.