MicroRNA-34a suppresses the invasion and migration of colorectal cancer cells by enhancing EGR1 and inhibiting vimentin

EGR1-Driven METTL3 Activation Curtails VIM-Mediated Neuron Injury in Epilepsy

Uncovering mechanisms underlying epileptogenesis aids in preventing further epilepsy progression and to lessen seizure severity and frequency. The purpose of this study is to explore the antiepileptogenic and neuroprotective mechanisms of EGR1 in neuron injuries encountered in epilepsy. Bioinformatics analysis was conducted to identify the key genes related to epilepsy. The mice were rendered epileptic using the kainic acid protocol, followed by measurement of seizure severity, high amplitude and frequency, pathological changes of hippocampal tissues and neuron apoptosis. Furthermore, an in vitro epilepsy model was constructed in the neurons isolated from newborn mice, which was then subjected to loss- and gain-of-function investigations, followed by neuron injury and apoptosis assessment. Interactions among EGR1, METTL3, and VIM were analyzed by a series of mechanistic experiments. In the mouse and cell models of epilepsy, VIM was robustly induced. However, its knockdown reduced hippocampal neuron injury and apoptosis. Meanwhile, VIM knockdown decreased inflammatory response and neuron apoptosis in vivo. Mechanistic investigations indicated that EGR1 transcriptionally activated METTL3, which in turn downregulated VIM expression through m6A modification. EGR1 activated METTL3 and reduced VIM expression, thereby impairing hippocampal neuron injury and apoptosis, preventing epilepsy progression. Taken together, this study demonstrates that EGR1 alleviates neuron injuries in epilepsy by inducing METTL3-mediated inhibition of VIM, which provides clues for the development of novel antiepileptic treatments.

WD40 repeat 43 mediates cell survival, proliferation, migration and invasion via vimentin in colorectal cancer

Background

WD40 repeat (WDR)43 is an RNA-binding protein that belongs to the WDR domain protein family. Its biological function is largely unclear, particularly in colorectal cancer (CRC).

Methods

In the present study, we searched the TCGA database and found the correlation between WDR43 and CRC. Subsequently, the high expression of WDR43 in human clinical samples of CRC was validated and we further examined the biological functions of it in CRC cells. Finally, we explored potential downstream proteins or pathways and established subcutaneous xenograft model to verify our findings.

Results

Immunohistochemistry of 16 patient specimens confirmed that the expression of WDR43 was elevated in CRC. WDR43 knockdown was shown to increase apoptosis and inhibit the proliferation, migration and invasion of CRC cells in vitro and reduce tumorigenesis in animal models. In addition, it was found that WDR43 knockdown inhibited vimentin (VIM) expression in CRC cells and overexpression of VIM can partially reverse the effects of WDR43 both in vitro and in vivo.

Conclusion

In conclusion, the role of WDR43 in the occurrence and development of CRC was investigated in the present study. WDR43 may serve as a valuable biomarker and provide new options for the diagnosis and treatment of colorectal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02109-1.

Interplay between DNA Methyltransferase 1 and microRNAs During Tumorigenesis

Cancer is a genetic disease resulting from genomic changes; however, epigenetic alterations act synergistically with these changes during tumorigenesis and cancer progression. Epigenetic variations are gaining more attention as an important regulator in tumor progression, metastasis and therapy resistance. Aberrant DNA methylation at CpG islands is a central event in epigeneticmediated gene silencing of various tumor suppressor genes. DNA methyltransferase 1 (DNMT1) predominately methylates at CpG islands on hemimethylated DNA substrates in proliferation of cells. DNMT1 has been shown to be overexpressed in various cancer types and exhibits tumor-promoting potential. The major drawbacks to DNMT1-targeted cancer therapy are the adverse effects arising from nucleoside and non-nucleoside based DNMT1 inhibitors. This paper focuses on the regulation of DNMT1 by various microRNAs (miRNAs), which may be assigned as future DNMT1 modulators, and highlights how DNMT1 regulates various miRNAs involved in tumor suppression. Importantly, the role of reciprocal inhibition between DNMT1 and certain miRNAs in tumorigenic potential is approached in this review. Hence, this review seeks to project an efficient and strategic approach using certain miRNAs in conjunction with conventional DNMT1 inhibitors as a novel cancer therapy. It has also been pinpointed to select miRNA candidates associated with DNMT1 regulation that may not only serve as potential biomarkers for cancer diagnosis and prognosis, but may also predict the existence of aberrant methylation activity in cancer cells.

The Role of microRNAs in Development of Colitis-Associated Colorectal Cancer

Colorectal cancer (CRC) is the third most deadly cancer worldwide, and inflammatory bowel disease (IBD) is one of the critical factors in CRC carcinogenesis. IBD is responsible for an unphysiological and sustained chronic inflammation environment favoring the transformation. MicroRNAs (miRNAs) belong to a class of highly conserved short single-stranded segments (18-25 nucleotides) non-coding RNA and have been extensively discussed in both CRC and IBD. However, the role of miRNAs in the development of colitis-associated CRC (CAC) is less clear. The aim of this review is to summarize the major upregulated (miR-18a, miR-19a, miR-21, miR-31, miR-155 and miR-214) and downregulated (miR-124, miR-193a-3p and miR-139-5p) miRNAs in CAC, and their roles in genes' expression modulation in chronic colonic-inflammation-induced carcinogenesis, including programmed cell-death pathways. These miRNAs dysregulation could be applied for early CAC diagnosis, to predict therapy efficacy and for precision treatment.

miR-34a mimic or pre-mir-34a, which is the better option for cancer therapy? KatoIII as a model to study miRNA action in human gastric cancer cells

Background

Aberrantly expressed microRNAs play important roles in gastric tumorigenesis. However, use of miRNAs as a therapeutic option in gastric cancer still remains as a challenging problem.

Methods

We performed transient transfection of miR-34a-5p mimic and stable transfection of pre-mir-34a into KatoIII cells. Then, we evaluated the effect of transfected miRNAs on numerous cellular and molecular processes.

Results

Following transient transfection of miR-34a-5p mimic at 25 nM—a commonly used concentration—into KatoIII cells, inhibition of two target genes expression, namely Notch1 and β-catenin, was not observed, but a non-significant marginal increase of these genes was detected. No changes were detected in the percentage of apoptotic cells as well as in CD44 + and EpCAM + cells after 25 nM miR-34a-5p mimic transfection. Interestingly, stable transfection of pre-mir-34a into KatoIII cells (named as KatoIII-pGFPC1-34a cells) caused a significant repression in β-catenin protein and Notch1 mRNA levels (p < 0.05 and p < 0.01, respectively) relative to equivalent control (KatoIII- pGFPC1-empty cells). The percentage of CD44 + cells in the KatoIII-pGFPC1-34a cells (< 40%) was significantly lower than that in control cells (~ 95%) (p < 0.05). An increase of ~ 3.5% in apoptotic cells and a slower proliferation rate were detected in KatoIII-pGFPC1-34a cells.

Conclusions

Our study revealed that the effect of miR mimic in target gene repression can be dependent to its concentration as well as to the cell type. Meanwhile, our findings further support a regulatory function for pre-miRNAs in target repression and will help to develop effective therapeutic strategies in cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01872-5.

A promising effect of zerumbone with improved anti-tumor-promoting inflammation activity of miR-34a in colorectal cancer cell lines

Cross-talk among inflammation and colorectal cancer cells is chiefly reported through a complex of cytokines, chemokines, and growth factors. MicroRNA performs strategic roles in controlling a variety of signaling cascades. miR-34a is known as a master regulator of tumor suppression. Combined application of different miRNA-based agents and chemotherapeutic drugs has been used to augment drug sensitivity and may reinforce the antitumor effect. A lot of studies specify a substantial increase in the effectiveness of combination therapies. The anti-inflammatory activity of Zerumbone (ZER) was investigated in many cancers. In this study the level of the inflammatory cytokines including CXCL-12 (SDF-1), CCL-2 (MCP-1), TGF-β and IL-33 has been measured in pmiR-34a-5p transfected and pmiR-34a-5p +ZER treated CRC cell lines (HCT-116 and SW48) by QRT-PCR and ELISA methods, respectively. The results showed that miR-34a could significantly inhibit cytokine expression in both cell lines for 48 and 72 h except SDF-1 which no inhibition was observed in SW48 cells. ZER suppressed SDF-1 for all three time points in both cell lines, while in SW48 cells IL-33 and TGF-β were inhibited in 72 h and in HCT-116 cells MCP-1 diminished for only 24 h and TGF-β diminished for all three times. Combination of both miR-34a and ZER suppressed TGF-β, SDF-1 and MCP-1 in HCT-116 cells in all time points while in SW48 cells, suppression of most cytokines was observed in 48 and 72 h. Furthermore Colony formation assay and scratch test were employed to detect changes of proliferation and migration in CRC transfected and treated cells. Generally, we found that miR-34a could considerably decrease the expression of inflammatory cytokines and the combination of ZER+ miR-34 boosted this effect. Moreover the migration and proliferation decreased in treated and transfected cells and this reduction was more severe in miR-34a +ZER treatment. It is important to note that in the case of cell resistance to each of these therapeutic agents, inhibition of cytokines can be compensated by another one.

Role of microRNA/Epithelial-to-Mesenchymal Transition Axis in the Metastasis of Bladder Cancer

Bladder cancer (BC) is the 11th most common diagnosed cancer, and a number of factors including environmental and genetic ones participate in BC development. Metastasis of BC cells into neighboring and distant tissues significantly reduces overall survival of patients with this life-threatening disorder. Recently, studies have focused on revealing molecular pathways involved in metastasis of BC cells, and in this review, we focus on microRNAs (miRNAs) and their regulatory effect on epithelial-to-mesenchymal transition (EMT) mechanisms that can regulate metastasis. EMT is a vital process for migration of BC cells, and inhibition of this mechanism restricts invasion of BC cells. MiRNAs are endogenous non-coding RNAs with 19-24 nucleotides capable of regulating different cellular events, and EMT is one of them. In BC cells, miRNAs are able to both induce and/or inhibit EMT. For regulation of EMT, miRNAs affect different molecular pathways such as transforming growth factor-beta (TGF-β), Snail, Slug, ZEB1/2, CD44, NSBP1, which are, discussed in detail this review. Besides, miRNA/EMT axis can also be regulated by upstream mediators such as lncRNAs, circRNAs and targeted by diverse anti-tumor agents. These topics are also discussed here to reveal diverse molecular pathways involved in migration of BC cells and strategies to target them to develop effective therapeutics.

Roles of miRNAs in Colorectal Cancer: Therapeutic Implications and Clinical Opportunities

Colorectal cancer (CRC) is one of the most disseminated diseases across the globe engaging the digestive system. Various therapeutic methods from traditional to the state-of-the-art ones have been applied in CRC patients, however, the attempts have been unfortunate to lead to a definite cure. MiRNAs are a smart group of non-coding RNAs having the capabilities of regulating and controlling coding genes. By utilizing this stock-in-trade biomolecules, not only disease’s symptoms can be eliminated, there may also be a good chance for the complete cure of the disease in the near future. Herein, we provide a comprehensive review delineating the therapeutic relationship between miRNAs and CRC. To this, various clinical aspects of miRNAs which act as a tumor suppressor and/or an oncogene, their underlying cellular processes and clinical outcomes, and, in particular, their effects and expression level changes in patients treated with chemo- and radiotherapy are discussed. Finally, based on the results deducted from scientific research studies, therapeutic opportunities based on targeting/utilizing miRNAs in the preclinical as well as clinical settings are highlighted.