Targeted regulation of MiR-98 on E2F1 increases chemosensitivity of leukemia cells K562/A02

MicroRNA-98: the multifaceted regulator in human cancer progression and therapy

MicroRNA-98 (miR-98) stands as an important molecule in the intricate landscape of oncology. As a subset of microRNAs, these small non-coding RNAs have accompanied a new era in cancer research, underpinning their significant roles in tumorigenesis, metastasis, and therapeutic interventions. This review provides a comprehensive insight into the biogenesis, molecular properties, and physiological undertakings of miR-98, highlighting its double-edged role in cancer progression-acting both as a tumor promoter and suppressor. Intriguingly, miR-98 has profound implications for various aspects of cancer progression, modulating key cellular functions, including proliferation, apoptosis, and the cell cycle. Given its expression patterns, the potential of miR-98 as a diagnostic and prognostic biomarker, especially in liquid biopsies and tumor tissues, is explored, emphasizing the hurdles in translating these findings clinically. The review concludes by evaluating therapeutic avenues to modulate miR-98 expression, addressing the challenges in therapy resistance, and assessing the efficacy of miR-98 interventions. In conclusion, while miR-98's involvement in cancer showcases promising diagnostic and therapeutic avenues, future research should pivot towards understanding its role in tumor-stroma interactions, immune modulation, and metabolic regulation, thereby unlocking novel strategies for cancer management.

The microRNA Let-7 and its exosomal form: Epigenetic regulators of gynecological cancers

Many types of gynecological cancer (GC) are often silent until they reach an advanced stage, and are therefore often diagnosed too late for effective treatment. Hence, there is a real need for more efficient diagnosis and treatment for patients with GC. During recent years, researchers have increasingly studied the impact of microRNAs cancer development, leading to a number of applications in detection and treatment. MicroRNAs are a particular group of tiny RNA molecules that regulate regular gene expression by affecting the translation process. The downregulation of numerous miRNAs has been observed in human malignancies. Let-7 is an example of a miRNA that controls cellular processes as well as signaling cascades to affect post-transcriptional gene expression. Recent research supports the hypothesis that enhancing let-7 expression in those cancers where it is downregulated may be a potential treatment option. Exosomes are tiny vesicles that move through body fluids and can include components like miRNAs (including let-7) that are important for communication between cells. Studies proved that exosomes are able to enhance tumor growth, angiogenesis, chemoresistance, metastasis, and immune evasion, thus suggesting their importance in GC management.

ATP-Binding Cassette Subfamily G Member 2 in Acute Myeloid Leukemia: A New Molecular Target?

Despite the progress in the knowledge of disease pathogenesis and the identification of many molecular markers as potential targets of new therapies, the cure of acute myeloid leukemia remains challenging. Disease recurrence after an initial response and the development of resistance to old and new therapies account for the poor survival rate and still make allogeneic stem cell transplantation the only curative option. Multidrug resistance (MDR) is a multifactorial phenomenon resulting from host-related characteristics and leukemia factors. Among these, the overexpression of membrane drug transporter proteins belonging to the ABC (ATP-Binding Cassette)-protein superfamily, which diverts drugs from their cellular targets, plays an important role. Moreover, a better understanding of leukemia biology has highlighted that, at least in cancer, ABC protein's role goes beyond simple drug transport and affects many other cell functions. In this paper, we summarized the current knowledge of ABCG2 (formerly Breast Cancer Resistance Protein, BCRP) in acute myeloid leukemia and discuss the potential ways to overcome its efflux function and to revert its ability to confer stemness to leukemia cells, favoring the persistence of leukemia progenitors in the bone marrow niche and justifying relapse also after therapy intensification with allogeneic stem cell transplantation.

The development of cancers research based on mitochondrial heat shock protein 90

Mitochondrial heat shock protein 90 (mtHsp90), including Tumor necrosis factor receptor-associated protein 1 (TRAP1) and Hsp90 translocated from cytoplasm, modulating cellular metabolism and signaling pathways by altering the conformation, activity, and stability of numerous client proteins, and is highly expressed in tumors. mtHsp90 inhibition results in the destabilization and eventual degradation of its client proteins, leading to interference with various tumor-related pathways and efficient control of cancer cell development. Among these compounds, gamitrinib, a specific mtHsp90 inhibitor, has demonstrated its safety and efficacy in several preclinical investigations and is currently undergoing evaluation in clinical trials. This review aims to provide a comprehensive overview of the present knowledge pertaining to mtHsp90, encompassing its structure and function. Moreover, our main emphasis is on the development of mtHsp90 inhibitors for various cancer therapies, to present a thorough overview of the recent pre-clinical and clinical advancements in this field.

Molecular Characterization of the Response to Conventional Chemotherapeutics in Pro-B-ALL Cell Lines in Terms of Tumor Relapse

Little is known about optimally applying chemotherapeutic agents in a specific temporal sequence to rapidly reduce the tumor load and to improve therapeutic efficacy. The clinical optimization of drug efficacy while reducing side effects is still restricted due to an incomplete understanding of the mode of action and related tumor relapse mechanisms on the molecular level. The molecular characterization of transcriptomic drug signatures can help to identify the affected pathways, downstream regulated genes and regulatory interactions related to tumor relapse in response to drug application. We tried to outline the dynamic regulatory reprogramming leading to tumor relapse in relapsed MLL-rearranged pro-B-cell acute lymphoblastic leukemia (B-ALL) cells in response to two first-line treatments: dexamethasone (Dexa) and cytarabine (AraC). We performed an integrative molecular analysis of whole transcriptome profiles of each treatment, specifically considering public knowledge of miRNA regulation via a network-based approach to unravel key driver genes and miRNAs that may control the relapse mechanisms accompanying each treatment. Our results gave hints to the crucial regulatory roles of genes leading to Dexa-resistance and related miRNAs linked to chemosensitivity. These genes and miRNAs should be further investigated in preclinical models to obtain more hints about relapse processes.

Advances in the application of Let-7 microRNAs in the diagnosis, treatment and prognosis of leukemia

The lethal-7 (Let-7) family of microRNAs (miRNAs) controls the process of development and differentiation, but is also related to the occurrence of tumors and a poor prognosis of patients with tumors. Thus, a more comprehensive exploration of its functions will provide further insights into these processes, and may promote the diagnosis and treatment of tumors. Leukemia is a type of progressive malignant disease, and its pathogenesis involves a variety of epigenetic factors. Amongst the several related epigenetic factors, the Let-7 miRNAs are an important family of molecules that play a crucial role in maintaining a variety of critical biological processes, including development, differentiation and proliferation. In the present study, the role of Let-7 as a tumor suppressor gene and oncogene is reviewed, and the complex regulatory functions of several Let-7 family members in different subtypes of leukemia are described. The current body of knowledge thus far indicates that Let-7 is not only a potential diagnostic and prognostic marker of leukemia, but also a potential therapeutic target for the treatment of affected patients, with particular potential when targeted by adjuvant treatments alongside traditional treatment to improve their survival rate.

Multidrug efflux transporter ABCG2: expression and regulation

The adenosine triphosphate (ATP)-binding cassette efflux transporter G2 (ABCG2) was originally discovered in a multidrug-resistant breast cancer cell line. Studies in the past have expanded the understanding of its role in physiology, disease pathology and drug resistance. With a widely distributed expression across different cell types, ABCG2 plays a central role in ATP-dependent efflux of a vast range of endogenous and exogenous molecules, thereby maintaining cellular homeostasis and providing tissue protection against xenobiotic insults. However, ABCG2 expression is subjected to alterations under various pathophysiological conditions such as inflammation, infection, tissue injury, disease pathology and in response to xenobiotics and endobiotics. These changes may interfere with the bioavailability of therapeutic substrate drugs conferring drug resistance and in certain cases worsen the pathophysiological state aggravating its severity. Considering the crucial role of ABCG2 in normal physiology, therapeutic interventions directly targeting the transporter function may produce serious side effects. Therefore, modulation of transporter regulation instead of inhibiting the transporter itself will allow subtle changes in ABCG2 activity. This requires a thorough comprehension of diverse factors and complex signaling pathways (Kinases, Wnt/β-catenin, Sonic hedgehog) operating at multiple regulatory levels dictating ABCG2 expression and activity. This review features a background on the physiological role of transporter, factors that modulate ABCG2 levels and highlights various signaling pathways, molecular mechanisms and genetic polymorphisms in ABCG2 regulation. This understanding will aid in identifying potential molecular targets for therapeutic interventions to overcome ABCG2-mediated multidrug resistance (MDR) and to manage ABCG2-related pathophysiology.

Emerging role of let-7 family in the pathogenesis of hematological malignancies

Let-7 includes a family of miRNA which are implicated in the developmental processes as well as carcinogenesis. This miRNA family has been shown to influence pathogenesis of a variety of hematological malignancies through changing expression of a number of oncogenic pathways, particularly those related with MYC. Expression of these miRNAs has been found to be different between distinct hematological malignancies or even between cytogenetically-defined subgroups of a certain malignancy. In the current review, we summarize the data regarding biogenesis, genomic locations, targets and regulatory network of this miRNA family in the context of hematological malignancies.

Let-7i Reduces Aggressive Phenotype and Induces BRCAness in Ovarian Cancer Cells

High-grade serous carcinoma of the ovary is a deadly gynecological cancer with poor long-term survival. Dysregulation of microRNAs has been shown to contribute to the formation of cancer stem cells (CSCs), an important part of oncogenesis and tumor progression. The let-7 family of microRNAs has previously been shown to regulate stemness and has tumor suppressive actions in a variety of cancers, including ovarian. Here, we demonstrate tumor suppressor actions of let-7i: repression of cancer cell stemness, inhibition of migration and invasion, and promotion of apoptosis, features important for cancer progression, relapse, and metastasis. Let-7i over-expression results in increased sensitivity to the PARP inhibitor olaparib in samples without BRCA mutations, consistent with induction of BRCAness phenotype. We also show that let-7i inhibits the expression of several factors involved in the homologous recombination repair (HRR) pathway, providing potential mechanisms by which the BRCAness phenotype could be induced. These actions of let-7i add to the rationale for use of this miRNA as a treatment for ovarian cancer patients, including those without mutations in the HRR pathway.

HOXA11-AS induces cisplatin resistance by modulating the microRNA-98/PBX3 axis in nasopharyngeal carcinoma

Long non-coding RNA homeobox A11-antisense RNA (HOXA11-AS) has been implicated in cisplatin (DDP) resistance in multiple types of cancer. The purpose of the present study was to investigate the role of HOXA11-AS in DDP-resistant nasopharyngeal carcinoma (NPC) cells. The expression levels of HOXA11-AS were examined using reverse transcription-quantitative PCR. Cell viability was measured using a Cell Counting Kit-8 assay, and a TUNEL assay was utilized to assess cell apoptosis. The expression levels of apoptosis-related factors (Bax and Bcl-2) were detected by western blot analysis. The interaction between microRNA-98 (miR-98) and HOXA11-AS or pre-B-cell leukemia homeobox 3 (PBX3) was demonstrated using bioinformatics analysis, dual-luciferase reporter assays and RNA immunoprecipitation assays. HOXA11-AS and PBX3 expressions levels were upregulated, whereas miR-98 levels were downregulated in DDP-resistant NPC tissues. Patients with NPC with high HOXA11-AS expression had a low survival rate. Knockdown of HOXA11-AS enhanced the DDP sensitivity of DDP-resistant NPC (5-8F/DDP and SUNE1/DDP) cells, which was demonstrated by the accelerated apoptosis. In addition, HOXA11-AS inhibited the expression levels of miR-98 through direct interaction. Furthermore, miR-98 inhibition counteracted the inductive effect of HOXA11-AS-knockdown on the DDP sensitivity of NPC cells. PBX3 was a target of miR-98 and was positively modulated by HOXA11-AS. Overexpression of PBX3 reversed the suppressive effect of HOXA11-AS silencing on the DDP resistance of NPC cells. The data demonstrated that HOXA11-AS enhanced DDP resistance in NPC via the miR-98/PBX3 axis, providing a potential therapeutic target for patients with DDP-resistant NPC.

MicroRNA let-7b downregulates AML1-ETO oncogene expression in t(8;21) AML by targeting its 3'UTR

Background

Acute myeloid leukemia (AML) with the t(8;21)(q22;q22) chromosomal translocation is among the most common subtypes of AML and produces the AML1-ETO (RUNX1-ETO, RUNX1-RUNX1T1) oncogenic fusion gene. AML1-ETO functions as an aberrant transcription factor which plays a key role in blocking normal hematopoiesis. Thus, the expression of AML1-ETO is critical to t(8;21) AML leukemogenesis and maintenance. Post-transcriptional regulation of gene expression is often mediated through interactions between trans-factors and cis-elements within transcript 3′-untranslated regions (UTR). AML1-ETO uses the 3′UTR of the ETO gene, which is not normally expressed in hematopoietic cells. Therefore, the mechanisms regulating AML1-ETO expression via the 3’UTR are attractive therapeutic targets.

Methods

We used RNA-sequencing of t(8;21) patients and cell lines to examine the 3′UTR isoforms used by AML1-ETO transcripts. Using luciferase assay approaches, we test the relative contribution of 3′UTR cis elements to AML1-ETO expression. We further use let-7b microRNA mimics and anti-let-7b sponges for functional studies of t(8;21) AML cell lines.

Results

In this study, we examine the regulation of AML1-ETO via the 3’UTR. We demonstrate that AML1-ETO transcripts primarily use a 3.7 kb isoform of the ETO 3′UTR in both t(8;21) patients and cell lines. We identify a negative regulatory element within the AML1-ETO 3′UTR. We further demonstrate that the let-7b microRNA directly represses AML1-ETO through this site. Finally, we find that let-7b inhibits the proliferation of t(8;21) AML cell lines, rescues expression of AML1-ETO target genes, and promotes differentiation.

Conclusions

AML1-ETO is post-transcriptionally regulated by let-7b, which contributes to the leukemic phenotype of t(8;21) AML and may be important for t(8;21) leukemogenesis and maintenance.

Diagnostic value of miR-637 in patients with atherosclerosis and its predictive significance for the future cardiovascular events

Objectives

Atherosclerosis is a common vascular disease. MiR-637 has been demonstrated to be low-expressed in hypertensive patients, and atherosclerosis is closely related to hypertension. Therefore, this study speculated that miR-637 may play an important role in the development of atherosclerosis. In brief, this study examined the expression level of miR-637 in patients with atherosclerosis and further analyzed its clinical value in patients with atherosclerosis.

Methods

The expression level of miR-637 was detected in serum from 86 patients with atherosclerosis and 75 healthy controls by using quantitative reverse transcription-polymerase chain reaction. The receiver operating characteristic curve was used to assess the diagnostic value of miR-637 in atherosclerosis. Pearson’s correlation analysis was performed to evaluate the relationship between serum miR-637 and different clinical parameters. The prognostic value of miR-637 in atherosclerosis was analyzed by the Kaplan–Meier survival curve and multivariate cox regression analysis.

Results

Compared with healthy individuals, miR-637 was downregulated in the serum of atherosclerosis patients. The receiver operating characteristic curve suggested the high diagnostic value of miR-637 for atherosclerosis, with the AUC of 0.853, specificity of 77.9%, and sensitivity of 80.0%. The expression level of miR-637 was negatively correlated with CIMT (r = –0.8101, P <  0.0001) and CRP (r = –0.6154, P <  0.0001), respectively. Survival analysis indicated that miR-637 was also found to be an independent prognostic factor for atherosclerosis.

Conclusions

MiR-637 is a potential noninvasive diagnostic marker of atherosclerosis and has important predictive value for the occurrence of future cardiovascular events.

The role of noncoding RNAs in epithelial cancer

Regulatory noncoding RNAs (ncRNAs) are a class of RNAs transcribed by regions of the human genome that do not encode for proteins. The three main members of this class, named microRNA, long noncoding RNA, and circular RNA play a key role in the regulation of gene expression, eventually shaping critical cellular processes. Compelling experimental evidence shows that ncRNAs function either as tumor suppressors or oncogenes by participating in the regulation of one or several cancer hallmarks, including evading cell death, and their expression is frequently deregulated during cancer onset, progression, and dissemination. More recently, preclinical and clinical studies indicate that ncRNAs are potential biomarkers for monitoring cancer progression, relapse, and response to cancer therapy. Here, we will discuss the role of noncoding RNAs in regulating cancer cell death, focusing on those ncRNAs with a potential clinical relevance.

Analysis of Let-7 Family miRNA in Plasma as Potential Predictive Biomarkers of Diagnosis for Papillary Thyroid Cancer

The most common histological type of thyroid cancer is papillary thyroid carcinoma (PTC). Radical resection of the thyroid gland is currently the recommended method of treatment. Almost 75% of thyroidectomies performed just for diagnostic purposes are benign. Thus, the confirmation of innovative and more precise noninvasive biomarkers holds promise for the detection of PTC, which may decrease the number of unnecessary thyroid lobectomies. In this work, using the droplet digital PCR (ddPCR) method, we have analyzed the level of five miRNAs (let-7a, let-7c, let-7d, let-7f, and let-7i) in the plasma of patients with PTC and compared them with those of a healthy control group to investigate whether miRNAs also have value in the management of PTC. Levels of four miRNAs, namely let-7a, let-7c, let-7d, and let-7f, were significantly higher in PTC patients than healthy controls. Thus, the analysis of circulating let-7 can be a useful tool and support the currently used methods for PTC diagnosis. However, our observation requires further research on a larger patient group.

miR-98 Modulates Cytokine Production from Human PBMCs in Systemic Lupus Erythematosus by Targeting IL-6 mRNA

Objective

There is evidence that interleukin-6 (IL-6) upregulation plays a critical role in immunopathology of systemic lupus erythematosus (SLE). MicroRNA- (miRNA-) 98 was predicted to bind with the 3′-untranslated region (3′-UTR) of IL-6 gene. We hypothesized miR-98 through its regulation of IL-6 gene expression to influence cytokine production from peripheral blood mononuclear cells (PBMCs) in SLE.

Methods

The expression of miR-98 and IL-6 mRNA in the PBMCs of 41 SLE patients and 20 healthy controls (HC) was detected by quantitative reverse transcription PCR (qRT-PCR). The correlations between miR-98 expression and clinical features were evaluated. Luciferase reporter assay was performed to identify miR-98 targets. miR-98 mimics, miR-98 inhibitor, and IL-6 overexpression vector were generated. Cell viability of PBMCs was assessed using MTT assay. Gene expression and protein level were determined by qRT-PCR and Western blotting. TNF-α, IL-8, IL-1β, and IL-10 levels in cultured supernatants were quantified using ELISA.

Results

The expression of miR-98 was downregulated in PBMCs of SLE patients, and its expression is negatively associated with IL-6 levels. miR-98 expression was correlated with disease activity, lupus nephritis, and anti-dsDNA antibody. IL-6 mRNA was a target gene of miR-98. IL-6 overexpression promoted the proliferation of PBMCs and increased the levels of TNF-α, IL-8, IL-1β, and IL-10. Those effects were further enhanced by miR-98 inhibitor, while were suppressed by miR-98 mimics. miR-98 regulated the levels of STAT3 phosphorylation via its target gene IL-6.

Conclusion

The current study revealed that miR-98 could ameliorate STAT3-mediated cell proliferation and inflammatory cytokine production via its target gene IL-6 in patients with SLE. These results suggest that miR-98 might serve as a potential target for SLE treatment and other IL-6-mediated diseases.

Let-7 as biomarker, prognostic indicator, and therapy for precision medicine in cancer

Abnormal regulation and expression of microRNAs (miRNAs) has been documented in various diseases including cancer. The miRNA let-7 (MIRLET7) family controls developmental timing and differentiation. Let-7 loss contributes to carcinogenesis via an increase in its target oncogenes and stemness factors. Let-7 targets include genes regulating the cell cycle, cell signaling, and maintenance of differentiation. It is categorized as a tumor suppressor because it reduces cancer aggressiveness, chemoresistance, and radioresistance. However, in rare situations let-7 acts as an oncogene, increasing cancer migration, invasion, chemoresistance, and expression of genes associated with progression and metastasis. Here, we review let-7 function as tumor suppressor and oncogene, considering let-7 as a potential diagnostic and prognostic marker, and a therapeutic target for cancer treatment. We explain the complex regulation and function of different let-7 family members, pointing to abnormal processes involved in carcinogenesis. Let-7 is a promising option to complement conventional cancer therapy, but requires a tumor specific delivery method to avoid toxicity. While let-7 therapy is not yet established, we make the case that assessing its tumor presence is crucial when choosing therapy. Clinical data demonstrate that let-7 can be used as a biomarker for rational precision medicine decisions, resulting in improved patient survival.

MicroRNAs and response to therapy in leukemia

A variety of epigenetic factors involved in leukemia pathogenesis. Among various epigenetic factors, microRNAs (miRNAs) have emerged as important players, which affect a sequence of cellular and molecular signaling pathways. Leukemia is known as progressive cancer, which is related to many health problems in the world. It has been shown that the destruction of the blood-forming organs could lead to abnormal effects on the proliferation and development of leukocytes and their precursors. Despite many attempts for approved effective and powerful therapies for patients with leukemia, finding and developing new therapeutic approaches are required. One of the important aspects of leukemia therapy, identification of underlying cellular and molecular mechanisms involved in the pathogenesis of leukemia. Several miRNAs (ie, miR-103, miR-101, mit-7, let-7i, miR-424, miR-27a, and miR-29c) and play major roles in response to therapy in patients with leukemia. miRNAs exert their effects by targeting a variety of targets, which are associated with response to therapy in patients with leukemia. It seems that more understanding about the roles of miRNAs in response to therapy in patients with leukemia could contribute to better treatment of patients with leukemia. Here, for the first time, we summarized various miRNAs, which are involved in response to therapy in the treatment patients with leukemia.

High expression of MiR-98 is a good prognostic factor in acute myeloid leukemia patients treated with chemotherapy alone

It has been demonstrated that microRNA-98 (miR-98) is dysregulated in multiple types of solid tumors, but its expression and impact in acute myeloid leukemia (AML) is unclear. To explore the prognostic role of miR-98 in AML, 164 AML patients with the miR-98 expression data were extracted from The Cancer Genome Atlas (TCGA) database and enrolled in this study. First, patients were divided into chemotherapy-only (chemotherapy) group and allogeneic hematopoietic stem cell transplant (allo-HSCT) group. Each group was then divided in two groups by the median expression level of miR-98. In chemotherapy group, high miR-98 expression was associated with longer event-free survival (EFS, P = 0.003) and overall survival (OS, P = 0.004), but in allo-HSCT group, EFS and OS were not significantly different between high and low miR-98 expressers. Second, All patients were divided in two groups by the median expression level of miR-98. In low miR-98 expressers, those treated with allo-HSCT had longer EFS (P = 0.001) and OS (P < 0.001) than chemotherapy, but in high miR-98 expressers, survival was independent from treatment modalities. Gene ontology enrichment analysis indicated that the genes associated with miR-98 expression were mainly concentrated in “definitive hemopoiesis”, “negative regulation of myeloid cell differentiation” and “signaling pathways regulating pluripotency of stem cells” pathways. In conclusion, our results indicated that high miR-98 expression confers good prognosis in AML patients treated with chemotherapy alone. Patients with low miR-98 expression may benefit from allo-HSCT.