The impact of Mir-9 regulation in normal and malignant hematopoiesis

MicroRNAs' Significance in Retinoblastoma Diagnosis and Treatment: The Little Heroes

One in 16, 000 live births is affected by the retinal tumor RB (retinoblastoma), which is frequently found in a child's early years. Both of the RB1 alleles that have been locally mutated in the affected retina are present in 60 percent of cases. Retinoblastoma (RB) can be detected using a variety of techniques, including imaging of the brain and orbits, eye examinations under anesthesia (EUAs), and the discovery of cell-free tumor DNA in samples of aqueous humor or plasma. In addition to the conventional surgical, chemotherapy, and radiotherapy approaches to treating retinoblastoma, new approaches have also been developed. Oncogenes, genes of tumor suppressors, and other molecular elements involved in cell growth and division interact complexly during the pathogenesis of retinoblastoma. The development of new therapies depends on comprehending the function of these molecular components. As a small class of non-coding RNAs capable of altering gene expression, microRNAs (miRNA) are understood to represent potential targets for the treatment of cancer. This study aimed to describe the changes in microRNA expression in some types of cancer, with a particular focus on retinoblastoma.

MicroRNA-9 inhibits proliferation and progression in retinoblastoma cells by targeting PTEN

BACKGROUND

Retinoblastoma (RB) is the most prevalent primary intraocular malignancy, which commonly occurs during infant and childhood.

OBJECTIVE

Our study aimed to investigate whether microRNA-9 (miR-9) could regulate RB cells and its mechanism.

METHODS

qRT-PCR analysis was used to detect the expression of miR-9. In addition, to detect the migration of RB cells, wound healing assay was conducted. Xenograft tumor models in nude mice were also established, in order to assess the effects of miR-9 on tumor growth. qRT-PCR, luciferase reporter assay and western blot analysis were used to detect the target of miR-9.

RESULTS

Initially, the expression level of miR-9 was significantly decreased in the RB tissues and blood samples from patients with RB. qRT-PCR, luciferase reporter assay and western blot analysis were used to confirm that PTEN was the target genes of miR-9 and it was negatively regulated by miR-9. When the expression of miR-9 was up-regulated, the cell viability, proliferation, migration and tumor formation were significantly suppressed. Furthermore, the expression level of PTEN was decreased after transfection of miR-9 mimic. Taken together, these results indicated that miR-9 might suppress the cell viability, proliferation, migration and tumor formation in RB by inhibiting PTEN.

CONCLUSION

The in vitro and in vivo experiments demonstrated that miR-9 acts as a tumor suppressor function in RB cells and might serve as novel therapeutic targets for the treatment of RB.

Inhibition of SIRT1 by microRNA-9, the key point in process of LPS-induced severe inflammation

Severe inflammation may lead to multiple organs dysfunction syndrome, which has a high mortality. MicroRNA is found participated in this process. In this study we developed a lipopolysaccharide-induced inflammation cell model on macrophages and a lipopolysaccharide-induced inflammation mouse model. It was found that during inflammation, microRNA-9 was increased, accompanied with the up-regulation of pro-inflammatory cytokines and anti-inflammatory cytokines. Down-regulation of microRNA-9 inhibited the up-regulation of inflammatory cytokines, promoted the up-regulation of anti-inflammatory cytokines and induced the remission of organ damage, showing a protective effect in inflammation. Bioinformatics analysis combined with luciferase reporter assay showed that SIRT1 was the target gene of microRNA-9. Transfection of microRNA-9 inhibitor could increase the level of SIRT1 and decrease the activation of NF-κB pathway in macrophages. Myeloid specific sirt1 knockout mice were included and we found that lack of SIRT1 in mice macrophages led to aggravated inflammation, cell apoptosis and organ injury, and eliminated the protective property of microRNA-9 inhibitor. In conclusion, we demonstrated that inhibition of microRNA-9 could alleviate inflammation through the up-regulation of SIRT1 and then suppressed the activation of NF-κB pathway. This is a meaningful explore about the specific mechanism of microRNA-9 in inflammation.

Aging, Melatonin, and the Pro- and Anti-Inflammatory Networks

Aging and various age-related diseases are associated with reductions in melatonin secretion, proinflammatory changes in the immune system, a deteriorating circadian system, and reductions in sirtuin-1 (SIRT1) activity. In non-tumor cells, several effects of melatonin are abolished by inhibiting SIRT1, indicating mediation by SIRT1. Melatonin is, in addition to its circadian and antioxidant roles, an immune stimulatory agent. However, it can act as either a pro- or anti-inflammatory regulator in a context-dependent way. Melatonin can stimulate the release of proinflammatory cytokines and other mediators, but also, under different conditions, it can suppress inflammation-promoting processes such as NO release, activation of cyclooxygenase-2, inflammasome NLRP3, gasdermin D, toll-like receptor-4 and mTOR signaling, and cytokine release by SASP (senescence-associated secretory phenotype), and amyloid-β toxicity. It also activates processes in an anti-inflammatory network, in which SIRT1 activation, upregulation of Nrf2 and downregulation of NF-κB, and release of the anti-inflammatory cytokines IL-4 and IL-10 are involved. A perhaps crucial action may be the promotion of macrophage or microglia polarization in favor of the anti-inflammatory phenotype M2. In addition, many factors of the pro- and anti-inflammatory networks are subject to regulation by microRNAs that either target mRNAs of the respective factors or upregulate them by targeting mRNAs of their inhibitor proteins.

The clinical significance of CDX2 in leukemia: A new perspective for leukemia research

CDX2 gene encodes a transcription factor involved in primary embryogenesis and hematopoietic development; however, the expression of CDX2 in adults is restricted to intestine and is not observed in blood tissues. The ectopic expression of CDX2 has been frequently observed in acute myeloid and lymphoid leukemia which in most cases is concomitant with poor prognosis. Induction of CDX2 in mice leads to hematologic complications, showing the leukemogenic origin of this gene. CDX2 plays significant role in the most critical pathways as the regulator of important transcription factors targeting cell proliferation, multi-drug resistance and survival. On the whole, the results indicate that CDX2 has the potential to be suggested as the diagnostic marker in hematologic malignancies. This review discusses the role of aberrant expression of CDX2 in the prognosis and the response to treatment in patients with different leukemia in clinical reports in the recent decades. The improvement in this regard could be of high importance in diagnosis and treatment methods.