Let-7c Inhibits the Proliferation, Invasion, and Migration of Glioma Cells via Targeting E2F5

Comparison of Oncogenes, Tumor Suppressors, and MicroRNAs Between Schizophrenia and Glioma: The Balance of Power

The risk of cancer in schizophrenia has been controversial. Confounders of the issue are cigarette smoking in schizophrenia, and antiproliferative effects of antipsychotic medications. The author has previously suggested comparison of a specific cancer like glioma to schizophrenia might help determine a more accurate relationship between cancer and schizophrenia. To accomplish this goal, the author performed three comparisons of data; the first a comparison of conventional tumor suppressors and oncogenes between schizophrenia and cancer including glioma. This comparison determined schizophrenia has both tumor-suppressive and tumor-promoting characteristics. A second, larger comparison between brain-expressed microRNAs in schizophrenia with their expression in glioma was then performed. This identified a core carcinogenic group of miRNAs in schizophrenia offset by a larger group of tumor-suppressive miRNAs. This proposed "balance of power" between oncogenes and tumor suppressors could cause neuroinflammation. This was assessed by a third comparison between schizophrenia, glioma and inflammation in asbestos-related lung cancer and mesothelioma (ALRCM). This revealed that schizophrenia shares more oncogenic similarity to ALRCM than glioma.

RGS16 regulated by let-7c-5p promotes glioma progression by activating PI3K-AKT pathway

Gliomas are the most common central nervous system tumours; they are highly aggressive and have a poor prognosis. RGS16 belongs to the regulator of G-protein signalling (RGS) protein family, which plays an important role in promoting various cancers, such as breast cancer, pancreatic cancer, and colorectal cancer. Moreover, previous studies confirmed that let-7c-5p, a well-known microRNA, can act as a tumour suppressor to regulate the progression of various tumours by inhibiting the expression of its target genes. However, whether RGS16 can promote the progression of glioma and whether it is regulated by miR let-7c-5p are still unknown. Here, we confirmed that RGS16 is upregulated in glioma tissues and that high expression of RGS16 is associated with poor survival. Ectopic deletion of RGS16 significantly suppressed glioma cell proliferation and migration both in vitro and in vivo. Moreover, RGS16 was validated as a direct target gene of miR let-7c-5p. The overexpression of miR let-7c-5p obviously downregulated the expression of RGS16, and knocking down miR let-7c-5p had the opposite effect. Thus, we suggest that the suppression of RGS16 by miR let-7c-5p can promote glioma progression and may serve as a potential prognostic biomarker and therapeutic target in glioma.

METTL3 promotes the growth and metastasis of pancreatic cancer by regulating the m6A modification and stability of E2F5

BACKGROUND

Pancreatic cancer belongs to lethal cancer with limited efficient treatment currently, and its main cause of death is rapid tumor growth and early metastasis. N6-methyladenosine (m6A) modification is a new method of epigenetic gene regulation involved in tumor progression, in which methyltransferase-like 3(METTL3) is the sole catalytic subunit. However, the role of METTL3 in pancreatic cancer remains to be explored.

METHODS

m6A level was measured using MeRIP assay, and RT-qPCR and western blot were applied to determine mRNA and protein expression, respectively. Cellular behaviors were detected using CCK-8, EdU, wound healing and transwell assays. Xenograft assays were conducted to further verify the roles of METTL3 in pancreatic cancer.

RESULTS

METTL3 was highly expressed in pancreatic cancer. However, downregulation of METTL3 restrained the viability, migration and invasion of pancreatic cancer cells. Moreover, E2F5 was found to be positively regulated by METTL3. Intriguingly, the anti-tumor functions of METTL3 knockdown in the phenotype of pancreatic cancer cells were overturned by overexpression of E2F5. Silencing METTL3 resulted in the decreased stability of E2F5 by methylating E2F5.

CONCLUSIONS

In conclusion, METTL3 can promote the malignant progression of pancreatic cancer by modifying E2F5 through m6A methylation to promote its stability.

Exosomes of A549 Cells Induced Migration, Invasion, and EMT of BEAS-2B Cells Related to let-7c-5p and miR-181b-5p

As carriers containing abundant biological information, exosomes could deliver the property of donor cells to recipient cells. Emerging studies have shown that tumor cells could secrete a mass of exosomes into the microenvironment to regulate bystander cells. However, the underlying mechanisms of such a phenomenon remain largely unexplored. In this research, we purified and identified the exosomes of A549 cells and found that A549-cell-derived exosomes promoted BEAS-2B cells migration, invasion, and epithelial-mesenchymal transition (EMT). Importantly, we observed that let-7c-5p and miR-181b-5p were attenuated in A549-cell-derived exosomes compared to BEAS-2B-cell-derived exosomes. The analysis of miRNA expression level in BEAS-2B cells indicated that incubation with A549-cell-derived exosomes reduced the expression levels of let-7c-5p and miR-181b-5p. In transient transfections assay, we found that downregulation of let-7c-5p and miR-181b-5p simultaneously showed stronger promotion of BEAS-2B cells migration and invasion than individually. Moreover, exosomes secreted from A549 cells with upregulated expression of let-7c-5p and miR-181b-5p significantly reduce their regulatory effect on BEAS-2B cells. Bioinformatics analyses revealed that let-7c-5p and miR-181b-5p inhibit the EMT process mainly by regulating focal adhesion and mitogen-activated protein kinase (MAPK) signaling pathway. Thus, our data demonstrated that A549-cell-derived exosomal let-7c-5p and miR-181b-5p could induce migration, invasion, and EMT in BEAS-2B cells, which might be regulated through focal adhesion and MAPK signaling pathway. The expression level of let-7c-5p and miR-181b-5p may show great significance for the early diagnosis of lung cancer.

Inhibition of HDACs Suppresses Cell Proliferation and Cell Migration of Gastric Cancer by Regulating E2F5 Targeting BCL2

(1) Background: Gastric cancer (GC) is the most common high death-rate cancer type worldwide, with an enhanced prevalence and increased rate of mortality. Although significant evidence on surgery strategy has been generated for the treatment of GC, conclusions are still uncertain regarding profound metastatic or persevering gastric cancer. Therefore, it is essential to develop novel and effective biomarkers or therapeutic targets for the diagnosis of GC. Histone deacetylations (HDACs) are important epigenetic regulators that control the aberrant transcription of critical genes that are mainly involved in cell proliferation, cell migration, regulation of the cell cycle, and different signal pathways. (2) Methods: Expression analysis of HDACs family members and E2F5 in gastric cancer cell lines was determined by RT-PCR and Western blotting. The cell proliferation was determined through an MTT assay. Cell migration was determined using a wound-healing assay. Flow cytometry experiments were used to determine cell-cycle analysis. The statistical software OriginPro 2015 (OriginLab, Northampton, MA, USA) was used to analyze data. A p value of < 0.05 was regarded as significant. (3) Results: The present study shows that E2F5 expression is upregulated in GC cancer cell lines compared to normal cell lines, and is positively associated with the level of HDACs and BCL2. HDACi and knocking down of E2F5 as tumor suppressors inhibited cell proliferation, migration invasion, and blocked the cell cycle in gastric cancer cells by suppressing BCL2. The results conclude that the anticancer mechanism of HDACi was determined by regulating E2F5 via targeting BCL2. (4) Conclusions: Our results suggest that the HDAC–E2F5–BCL2 signaling axis might be a novel potential biomarker in gastric cancer.

Lin28A promotes the proliferation and stemness of lung cancer cells via the activation of mitogen-activated protein kinase pathway dependent on microRNA let-7c

Background

Among patients with lung cancer, metastatic and relapsed cases account for the largest proportion of disease-associated deaths. Tumor metastasis and relapse are believed to originate from cancer stem cells (CSCs), which have the capacity to be highly proliferative and invasive. In our previous studies, we established a conditional basement membrane extract-based (BME-based) 3-dimensional (3D) culture system to mimic the tumor growth environment in vivo and further amplified lung cancer stem cells (LCSCs) in our system. However, the molecular mechanisms of LCSC amplification and development in our 3D culture system have not been fully uncovered.

Method

We established the conditional 3D culture system to amplify LCSCs in other lung cancer cell lines, followed by examining the expression of Lin28A and let-7 microRNAs in them. We also explored the expression of Lin28A and let-7 microRNAs in LCSCs from clinical lung cancer tissue samples and even analyzed the correlation of Lin28A/let-7c and patients’ survival outcomes. We further constructed A549 cells either knockdown of Lin28A or overexpression of let-7c, followed by investigating stemness marker gene expression, and stemness phenotypes including mammosphere culture, cell migration and invasion in vitro, as well as tumorigenicity in vivo.

Results

Here, we observed that Lin28A/let-7c was dysregulated in LCSCs in both the 3D culture system and lung cancer tissues. Further, the abnormal expression of Lin28A/let-7c was correlated with poor survival outcomes. Via the construction of A549 cells with let-7c over-expression, we found that let-7c inhibited the maintenance of LCSC properties, while the results of Lin28A knockdown showed that Lin28A played a critical role in the enrichment and proliferation of LCSCs via mitogen-activated protein kinase (MAPK) signaling pathway. Importantly, we found that LCSCs with knockdown of Lin28A or over-expression of let-7c exhibited inhibited carcinogenesis and disrupted expansion in vivo.

Conclusions

Our study uncovered the functions and mechanisms of the Lin28A/let-7c/MAPK signaling pathway in promoting the proliferation and cancer stemness of LCSCs, which might be a potential therapeutic target for reducing and even eliminating LCSCs in the future.

Expression, Prognosis, and Immune Infiltrates Analyses of E2Fs in Human Brain and CNS Cancer

Objective

We investigated the expression patterns, potential functions, unique prognostic value, and potential therapeutic targets of E2Fs in brain and CNS cancer and tumor-infiltrating immune cell microenvironments.

Methods

We analyzed E2F mRNA expression levels in diverse cancer types via Oncomine and GEPIA databases, respectively. Moreover, we evaluated the prognostic values using GEPIA database and TCGAportal database and the correlation of E2F expression with immune infiltration and the correlation between immune cell infiltration and GBM and LGG prognosis via TIMER database. Then, cBioPortal, GeneMANIA, and DAVID databases were used for mutation analysis, PPI network analysis of coexpressed gene, and functional enrichment analysis.

Results

E2F1-8 expression increased in most cancers, including brain and CNS cancer. Higher expression in E2F1, 2, 4, 6, 7, and 8 indicated poor OS of LGG. Higher E2F3–6 and E2F1–8 expressions correlated with poor prognosis and increased immune infiltration levels in CD8+ T cells, macrophages, neutrophils, and DCs in GBM and CD8+ T cells, B cells, CD4+ T cells, neutrophils, macrophages, and DCs in LGG, respectively.

Conclusion

E2F1–8 and E2F2–8 could be hopeful prognostic biomarkers of GBM and LGG, respectively. E2F3–6 and E2F1–8 could be likely therapeutic targets in patients with immune cell infiltration of GBM and LGG, respectively.

Let-7c-5p Inhibits Cell Proliferation and Migration and Promotes Apoptosis via the CTHRC1/AKT/ERK Pathway in Esophageal Squamous Cell Carcinoma

PURPOSE

Let-7c-5p has been identified as a tumor suppressor in various malignancies; however, its function and mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we explored the role and potential molecular mechanism of let-7c-5p in ESCC.

MATERIALS AND METHODS

mRNA and protein expression levels were detected by quantitative real time-polymerase chain reaction (qRT-PCR) and Western blotting. The cell counting kit-8 (CCK-8) assay was used to assess cell proliferation. Flow cytometry analysis was used to detect cell apoptosis, and cell migration was measured by wound healing assay and Transwell assays. The dual-luciferase reporter assay was used to verify the targeting relationship between let-7c-5p and CTHRC1. The tumor xenograft model was constructed to further verify the effect of let-7c-5p on the growth of ESCC in vivo.

RESULTS

We found that let-7c-5p expression was downregulated in ESCC tissue and cell lines, and its reduced expression was correlated with TNM staging and lymph node metastasis. Next, we found that let-7c-5p can be used to discriminate ESCC patients from normal control subjects by receiver operating characteristic (ROC) curve analysis. Subsequently, we observed that let-7c-5p overexpression inhibited proliferation and migration and promoted apoptosis, while let-7c-5p down-regulation promoted proliferation and migration and inhibited apoptosis of TE-1 and KYSE150 cells. Furthermore, let-7c-5p overexpression inhibited tumor growth, while let-7c-5p inhibition promoted tumor growth in xenograft models. In addition, we confirmed that CTHRC1 was a direct target gene of let-7c-5p. Then, we found that let-7c-5p level was negatively correlated with CTHRC1 and negatively regulated expression of CTHRC1 in ESCC. Moreover, we confirmed that let-7c-5p upregulation significantly reduced the phosphorylation of AKT and ERK by directly inhibiting CTHRC1, while let-7c-5p downregulation showed the opposite effect.

CONCLUSION

Our findings indicate that let-7c-5p is markedly downregulated in ESCC and suppresses proliferation and migration and promotes apoptosis of ESCC cells by inhibiting the AKT and ERK signaling pathways through negatively regulating CTHRC1. Therefore, these results suggest that let-7c-5p may represent a novel biomarker and therapeutic target for ESCC.

Hsa-let-7c exerts an anti-tumor function by negatively regulating ANP32E in lung adenocarcinoma

We attempted to investigate the relationship between hsa-let-7c and ANP32E, as well as their influence on the cells phenotype of lung adenocarcinoma. Expression of hsa-let-7c and prognostic values were assessed by bioinformatics analysis based on TCGA database. Quantitative real-time PCR and western blot was employed to measure relative expression of hsa-let-7c or ANP32E. The targeting relationship between let-7c and ANP32E was predicted by biological software and validated by dual luciferase reporter assay. With gene transfection technology, cell proliferation, invasion and migration were appraised by cell counting Kit-8, clone formation and Transwell assays. The results showed that hsa-let-7c was downregulated in lung adenocarcinoma. Downregulation of hsa-let-7c notably led to a poor survival. ANP32E was forecasted and confirmed as a directly target of hsa-let-7c, and was upregulated in lung adenocarcinoma. Furthermore, upregulation of ANP32E had a significant correlation with unsatisfactory survival. Meanwhile, the levels of ANP32E were negatively regulated by hsa-let-7c. Upregulation of hsa-let-7c remarkably suppressed the Calu-3 cell proliferation, invasion and migration, while ANP32E overexpression plasmids rescued the downtrend. Inversely, hsa-let-7c silencing in NCI-H209 cells presented the opposite outcomes. Collectively, hsa-let-7c shows an anti-tumor effect in lung adenocarcinoma by targeting ANP32E and is expected to be a potential therapeutic target for lung adenocarcinoma.

Epigenetic Drugs for Cancer and microRNAs: A Focus on Histone Deacetylase Inhibitors

Over recent decades, it has become clear that epigenetic abnormalities are involved in the hallmarks of cancer. Histone modifications, such as acetylation, play a crucial role in cancer development and progression, by regulating gene expression, such as for oncogenes or tumor suppressor genes. Therefore, histone deacetylase inhibitors (HDACi) have recently shown efficacy against both hematological and solid cancers. Designed to target histone deacetylases (HDAC), these drugs can modify the expression pattern of numerous genes including those coding for micro-RNAs (miRNA). miRNAs are small non-coding RNAs that regulate gene expression by targeting messenger RNA. Current research has found that miRNAs from a tumor can be investigated in the tumor itself, as well as in patient body fluids. In this review, we summarized current knowledge about HDAC and HDACi in several cancers, and described their impact on miRNA expression. We discuss briefly how circulating miRNAs may be used as biomarkers of HDACi response and used to investigate response to treatment.