MicroRNA-338-3p Inhibits Proliferation and Promotes Apoptosis of Multiple Myeloma Cells Through Targeting Cyclin-Dependent Kinase 4

miRNAs driving diagnosis, progression, and drug resistance in multiple myeloma

Multiple myeloma (MM) is a tumor of transformed plasma cells. It's the second most common hematologic cancer after non-Hodgkin lymphoma. MM is a complex disease with many different risk factors, including ethnicity, race, and epigenetics. The microRNAs (miRNAs) are a critical epigenetic factor in multiple myeloma, influencing key aspects such as pathogenesis, prognosis, and resistance to treatment. They have the potential to assist in disease diagnosis and modulate the resistance behavior of MM towards therapeutic regimens. These characteristics could be attributed to the modulatory effects of miRNAs on some vital pathways such as NF-KB, PI3k/AKT, and P53. This review discusses the role of miRNAs in MM with a focus on their role in disease progression, diagnosis, and therapeutic resistance.

Exosomal miRNAs in the Tumor Microenvironment of Multiple Myeloma

Multiple myeloma (MM) is a malignancy of plasma cells in the bone marrow and is characterized by the clonal proliferation of B-cells producing defective monoclonal immunoglobulins. Despite the latest developments in treatment, drug resistance remains one of the major challenges in the therapy of MM. The crosstalk between MM cells and other components within the bone marrow microenvironment (BME) is the major determinant of disease phenotypes. Exosomes have emerged as the critical drivers of this crosstalk by allowing the delivery of informational cargo comprising multiple components from miniature peptides to nucleic acids. Such material transfers have now been shown to perpetuate drug-resistance development and disease progression in MM. MicroRNAs(miRNAs) specifically play a crucial role in this communication considering their small size that allows them to be readily packed within the exosomes and widespread potency that impacts the developmental trajectory of the disease inside the tumor microenvironment (TME). In this review, we aim to provide an overview of the current understanding of the role of exosomal miRNAs in the epigenetic modifications inside the TME and its pathogenic influence on the developmental phenotypes and prognosis of MM.

A review on the role of cyclin dependent kinases in cancers

The Cyclin-dependent kinase (CDK) class of serine/threonine kinases has crucial roles in the regulation of cell cycle transition and is mainly involved in the pathogenesis of cancers. The expression of CDKs is controlled by a complex regulatory network comprised of genetic and epigenetic mechanisms, which are dysregulated during the progression of cancer. The abnormal activation of CDKs results in uncontrolled cancer cell proliferation and the induction of cancer stem cell characteristics. The levels of CDKs can be utilized to predict the prognosis and treatment response of cancer patients, and further understanding of the function and underlying mechanisms of CDKs in human tumors would pave the way for future cancer therapies that effectively target CDKs. Defects in the regulation of cell cycle and mutations in the genes coding cell-cycle regulatory proteins lead to unrestrained proliferation of cells leading to formation of tumors. A number of treatment modalities have been designed to combat dysregulation of cell cycle through affecting expression or activity of CDKs. However, effective application of these methods in the clinical settings requires recognition of the role of CDKs in the progression of each type of cancer, their partners, their interactions with signaling pathways and the effects of suppression of these kinases on malignant features. Thus, we designed this literature search to summarize these findings at cellular level, as well as in vivo and clinical levels.

Circular RNA in multiple myeloma: A new target for therapeutic intervention

Circular RNAs (circRNAs) are RNA molecules with a stable closed-loop structure that are found in a variety of organisms. CircRNAs are highly stable and conserved, and they play important roles in transcriptional regulation and splicing. Multiple Myeloma (MM) is a malignant proliferative disease for which there are currently no effective and comprehensive treatments. Numerous circRNAs may contribute to the development and progression of MM by acting as oncogenes or regulators. Due to the unique function of circRNAs, they have a high potential for regulating the biological functions (including proliferation and apoptosis) of MM cells, and their expression levels and molecular mechanism are closely related to their diagnostic value, therapeutic sensitivity, and clinical prognosis of MM patients. In this review, we aim to provide a detailed overview of the structure and function of circRNAs and demonstrate the potential therapeutic value and potential mechanism of circRNAs in MM via experiments and clinical trials.

The Multiple Myeloma Landscape: Epigenetics and Non-Coding RNAs

Simple Summary

Recent findings in multiple myeloma have led to therapies which have improved patient life quality and expectancy. However, frequent relapse and drug resistance emphasize the need for more efficient therapeutic approaches. The discovery of non-coding RNAs as key actors in multiple myeloma has broadened the molecular landscape of this disease, together with classical epigenetic factors such as methylation and acetylation. microRNAs and long non-coding RNAs comprise the majority of the described non-coding RNAs dysregulated in multiple myeloma, while circular RNAs are recently emerging as promising molecular targets. This review provides a comprehensive overview of the most recent knowledge on this topic and suggests new therapeutic strategies.

Abstract

Despite advances in available treatments, multiple myeloma (MM) remains an incurable disease and represents a challenge in oncohematology. New insights into epigenetic factors contributing to MM development and progression have improved the knowledge surrounding its molecular basis. Beyond classical epigenetic factors, including methylation and acetylation, recent genome analyses have unveiled the importance of non-coding RNAs in MM pathogenesis. Non-coding RNAs have become of interest, as their dysregulation opens the door to new therapeutic approaches. The discovery, in the past years, of molecular techniques, such as CRISPR-Cas, has led to innovative therapies with potential benefits to achieve a better outcome for MM patients. This review summarizes the current knowledge on epigenetics and non-coding RNAs in MM pathogenesis.

Down-regulation of circ_0058058 suppresses proliferation, angiogenesis and metastasis in multiple myeloma through miR-338-3p/ATG14 pathway

Background

Multiple myeloma (MM) is one of the most frequently diagnosed hematological malignancy. Dysregulation of circular RNAs (circRNAs) has important impacts on MM process. Herein, this work aimed to investigate the role and mechanism of circ_0058058 in MM progression.

Methods

Levels of genes and proteins were detected by real-time reverse transcription PCR (RT-qPCR) and Western blot. CCK-8 assay, colony formation assay, EdU assay, flow cytometry, tube formation assay, transwell assay and Western blot were utilized to detect the proliferation, apoptosis, angiogenesis and metastasis of MM cells. The target relationship between miR-338-3p and circ_0058058 or ATG14 (autophagy related 14) was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. In vivo experiments were performed using Xenograft assay.

Results

Circ_0058058 was up-regulated in MM bone marrow aspirates and cells, knockdown of circ_0058058 reduced MM cell proliferation, angiogenesis and metastasis, but induced apoptosis in vitro. In a MM xenograft mouse model, circ_0058058 silencing reduced MM tumor growth and cell proliferation. Mechanistically, circ_0058058 acted as a sponge for miR-338-3p to up-regulate ATG14 expression, which was validated to be a target of miR-338-3p. Rescue assay showed that miR-338-3p inhibition reversed the antitumor effects of circ_0058058 knockdown on MM cell. Moreover, forced expression of miR-338-3p suppressed MM cell malignant phenotype, which was abolished by ATG14 up-regulation.

Conclusion

Circ_0058058 functions as a sponge for miR-338-3p to elevate ATG14 expression to promote MM cell proliferation, metastasis and angiogenesis, affording a potential therapeutic target for MM prevention.

Roles of miRNA dysregulation in the pathogenesis of multiple myeloma

Multiple myeloma (MM) is a malignant disease of plasma cells with complex pathology, causing significant morbidity due to its end-organ destruction. The outcomes of patients with myeloma have significantly improved in the past couple of decades with the introduction of novel agents, such as proteasome inhibitors, immunomodulators, and monoclonal antibodies. However, MM remains incurable and presents considerable individual heterogeneity. MicroRNAs (miRNAs) are short, endogenous noncoding RNAs of 19-22 nucleotides that regulate gene expression at the posttranscriptional level. Numerous studies have shown that miRNA deregulation is closely related to MM pathology, including tumor initiation, progression, metastasis, prognosis, and drug response, which make the complicated miRNA network an attractive and marvelous area of investigation for novel anti-MM therapeutic approaches. Herein, we mainly summarized the current knowledge on the roles of miRNAs, which are of great significance in regulating pathological factors involved in MM progressions, such as bone marrow microenvironment, methylation, immune regulation, genomic instability, and drug resistance. Meanwhile, their potential as novel prognostic biomarkers and therapeutic targets was also discussed.

High expression of CPNE5 and CPNE9 predicts positive prognosis in multiple myeloma

BACKGROUND

CPNEs are significant biomarkers which can affect the progression and prognosis of various tumor diseases. However, the prognosis role of CPNEs in multiple myeloma (MM) is still unclear.

OBJECTIVES

To investigate the prognosis role of CPNEs in MM.

METHODS

Seven hundred and thirty-five samples from two independent data sets were involved to analyze the clinical and molecular characteristics, and prognosis role of the expression of CPNE1-9 in MM.

RESULTS

MM patients with higher expressions of CPNE5 and CPNE9 had longer event-free survival (EFS) and overall survival (OS) compared with CPNE5low and CPNE9low expression groups (EFS: P= 0.0054, 0.0065; OS: P= 0.015, 0.016, respectively). Multivariate regression analysis showed that CPNE5 was an independent favorable predictor for EFS and OS (EFS: P= 0.005; OS: P= 0.006), and CPNE9 was an independent positive indicator for EFS (P= 0.002). Moreover, the survival probability and the cumulative event of EFS and OS in CPNE5highCPNE9high group were significantly longer than other groups.

CONCLUSIONS

High expressions of CPNE5 and CPNE9 might be used as positive indicators for MM, and their combination was a better predictor for the survival of MM patients.

Long non-coding RNA ANRIL and its target microRNAs (microRNA-34a, microRNA-125a and microRNA-186) relate to risk stratification and prognosis in multiple myeloma

OBJECTIVE

This study aimed to investigate the correlations of long non-coding RNA ANRIL (lncRNA ANRIL), microRNA (miR)-34a, miR-125a and miR-186 with disease risk, clinical features and prognosis of multiple myeloma (MM).

METHOD

Totally, 87 MM patients and 30 controls were recruited. LncRNA ANRIL and its target miRNAs (miR-34a, miR-125a and miR-186) in bone marrow derived plasma cells were detected by RT-qPCR. Treatment response was assessed and survivals were calculated in MM patients.

RESULTS

LncRNA ANRIL expression was increased, while miR-34a, miR-125a and miR-186 expressions were reduced in MM patients compared with controls. Meanwhile, lncRNA ANRIL negatively correlated with miR-34a and miR-125a but not miR-186 in MM patients, while did not correlate with miR-34a, miR-125a or miR-186 in controls. In MM patients, lncRNA ANRIL high expression associated with higher beta-2-microglobulin (β2-MG) and more advanced international staging system (ISS) stage; miR-125a high expression associated with lower β2-MG, less advanced ISS stage and less t (14; 16) abnormality; miR186 high expression associated with increased albumin; while miR-34a did not associate with any clinical features. Furthermore, lncRNA ANRIL high expression associated with decreased complete response (CR), while miR-34a high and miR-125a high expression associated with increased CR and objective response rate. Additionally, lncRNA ANRIL high expression associated with shorter progression-free survival (PFS), while miR-34a high expression associated with prolonged overall survival (OS), and miR-125a high expression associated with longer PFS and OS.

CONCLUSION

LncRNA ANRIL and its target miRNAs might serve as biomarkers for assisting with personalized treatment and prognosis improvement of MM.

A minor review of microRNA-338 exploring the insights of its function in tumorigenesis

MicroRNAs(miRNAs) are small non-coding RNAs which have a critical role in various biological processes via direct binding and post-transcriptionally regulating targeted genes expression. More than one-half of human genes were regulated by miRNAs and their aberrant expression was detected in various human diseases, including cancers. miRNA-338 is a new identified miRNA and increasing evidence show that miRNA-338 participates in the progression of lots of cancers, such as lung cancer, hepatocellular cancer, breast cancer, glioma, and so on. Although a range of targets and signaling pathways such as MACC1 and Wnt/β-catenin signaling pathway were illustrated to be regulated by miRNA-338, which functions in tumor progression are still ambiguous and the underlying molecular mechanisms are also unclear. Herein, we reviewed the latest studies in miRNA-338 and summarized its roles in different type of human tumors, which might provide us new idea for further investigations and potential targeted therapy.

Silencing of circular RNA_0000326 inhibits cervical cancer cell proliferation, migration and invasion by boosting microRNA-338-3p-dependent down-regulation of CDK4

Cervical cancer is one of the leading causes of cancer-related death among women, which is attributed partly by limited treatment options. Recent studies have provided in-depth explanations regarding the role of circular RNA in cancers. We aimed to investigate the role of circular RNA_0000326 in cervical cancer. Bioinformatics analysis revealed a high circ_0000326 expression in cervical cancer. Cervical cancer cells and tissues were also observed to have elevated levels of circ_0000326 and the upregulation of circ_0000326 depended on the stage of cancer. Transfection with siRNA of circ_0000326 resulted in the inhibition of proliferation, migration and cell cycle of cancer cells. Interestingly, we confirmed that circ_0000326 served as a sponge for microRNA-338-3p and that the miRNA bound to Cyclin-dependent kinase 4. In the presence of microRNA-338-3p mimic or silencing of circ_0000326, Cyclin-dependent kinase 4 expression was decreased. Transfection with microRNA-338-3p mimic inhibited cell clone formation and proliferation. Moreover, in vivo experiment revealed that the injection of shRNA-circ_0000326 lentivirus suppressed tumor growth and decreased Cyclin-dependent kinase 4 expression. Taken altogether, our results showed that circ_0000326 exerted oncogenic effects on cervical cancer by upregulating Cyclin-dependent kinase 4 via sponging microRNA-338-3p. This systematic investigation on circ_0000326 could provide further insight into cervical cancer.

The role of microRNA-338-3p in cancer: growth, invasion, chemoresistance, and mediators

Cancer still remains as one of the leading causes of death worldwide. Metastasis and proliferation are abnormally increased in cancer cells that subsequently, mediate resistance of cancer cells to different therapies such as radio-, chemo- and immune-therapy. MicroRNAs (miRNAs) are endogenous short non-coding RNAs that can regulate expression of target genes at post-transcriptional level and capable of interaction with mRNA-coding genes. Vital biological mechanisms including apoptosis, migration and differentiation are modulated by these small molecules. MiRNAs are key players in regulating cancer proliferation and metastasis as well as cancer therapy response. MiRNAs can function as both tumor-suppressing and tumor-promoting factors. In the present review, regulatory impact of miRNA-338-3p on cancer growth and migration is discussed. This new emerging miRNA can regulate response of cancer cells to chemotherapy and radiotherapy. It seems that miRNA-338-3p has dual role in cancer chemotherapy, acting as tumor-promoting or tumor-suppressor factor. Experiments reveal anti-tumor activity of miRNA-338-3p in cancer. Hence, increasing miRNA-338-3p expression is of importance in effective cancer therapy. Long non-coding RNAs, circular RNAs and hypoxia are potential upstream mediators of miRNA-338-3p in cancer. Anti-tumor agents including baicalin and arbutin can promote expression of miRNA-338-3p in suppressing cancer progression. These topics are discussed to shed some light on function of miRNA-338-3p in cancer cells.

Circ_0007841 promotes the progression of multiple myeloma through targeting miR-338-3p/BRD4 signaling cascade

Background

The pathogenesis of multiple myeloma (MM) is not completely known. Uncovering the potential mechanism of MM initiation and progression is essential for identifying novel diagnostic and therapeutic targets. Herein, we explored the function and the working mechanism of circular RNA circ_0007841 in MM progression.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to detect the expression of circ_0007841, microRNA-338-3p (miR-338-3p) and bromodomain containing 4 (BRD4). Cell proliferation ability was analyzed through cell counting kit-8 (CCK8) assay, colony formation assay and flow cytometry. Transwell assays were conducted to measure the migration and invasion abilities of MM cells. Cell apoptosis was also assessed by flow cytometry. The interaction between miR-338-3p and circ_0007841 or BRD4 was confirmed by dual-luciferase reporter assay and RNA-pull down assay.

Results

Circ_0007841 was highly expressed in bone marrow (BM)-derived plasma cells of MM patients and MM cell lines than that in healthy volunteers and normal plasma cell line nPCs. Circ_0007841 promoted the proliferation, cell cycle and metastasis and impeded the apoptosis of MM cells. miR-338-3p was a direct target of circ_0007841 in MM cells and circ_0007841 accelerated the progression of MM through targeting miR-338-3p. BRD4 could directly bind to miR-338-3p in MM cells and miR-338-3p exerted an anti-tumor role through targeting BRD4. Circ_0007841 promoted the activation of PI3K/AKT signaling via miR-338-3p/BRD4 axis. Exosomes generated from mesenchymal stromal cells (MSCs) elevated the malignant behaviors of MM cells via circ_0007841.

Conclusion

Circ_0007841 acted as an oncogene to promote the proliferation, cell cycle and motility and restrain the apoptosis of MM cells through sequestering miR-338-3p to up-regulate the expression of BRD4.

MicroRNA-338-3p suppresses cell proliferation, migration and invasion in human malignant melanoma by targeting MACC1

Malignant melanoma (MM) is the most aggressive form of skin cancer originating from melanocytes with increased proliferative and metastatic ability. Previous studies have revealed that microRNA-338-3p (miR-338-3p) functions as a tumor suppressor in several types of cancer, including cervical cancer, renal cell carcinoma and thyroid cancer. However, the function and mechanism underlying the action of miR-383-3p in MM remain unclear. In the study, aberrant downregulation of miR-338-3p was observed in 60 pairs of MM and adjacent non-tumor tissue using quantitative polymerase chain reaction assay. Decreased miR-383-3p expression was associated with advanced clinical stage (P<0.05) and lymph node metastasis (P<0.001). The overexpression of miR-338-3p in A375 and G361 cells suppressed cell proliferation and migration using MTT, colony formation, wound healing and transwell assays. Mechanistically, MACC1 was identified as a direct target for miR-338-3p using bioinformatics prediction and dual-luciferase assays. Furthermore, MACC1 expression was significantly increased and inversely correlated with the levels of miR-338-3p in MM tissues. More importantly, restoration of MACC1 resulted in reversed the inhibitory effects of miR-338-3p overexpression on MM cells by altering the expression levels of PCNA and epithelial-mesenchymal transition (EMT)-associated proteins. These results suggest that miR-338-3p functions as a novel tumor suppressor, at least in part, via targeting MACC1 and suggest that miR-338-3p may serve as a potential target for treatment of MM patients.

MicroRNA-765 is pregulated in multiple myeloma and serves an oncogenic role by directly targeting SOX6

Increasing evidence has revealed that microRNAs (miRNAs) are closely associated with multiple myeloma (MM) pathogenesis and progression. Therefore, an in-depth understanding of the biological functions of miRNAs in MM may be helpful for the identification of promising therapeutic techniques for patients with MM. miRNA-765 (miR-765) has been reported to be dysregulated in many types of human cancer. However, the expression pattern, specific roles and underlying mechanisms of miR-765 in MM remain largely unknown. In the present study, plasma miR-765 significantly increased in patients with MM and cell lines. The downregulation of miR-765 in MM cells attenuated proliferation and promoted apoptosis. Bioinformatics analysis predicted that SRY-Box 6 (SOX6) was a putative target of miR-765. This was experimentally verified using a luciferase reporter assay, reverse transcription-quantitative PCR and western blot analysis. Furthermore, plasma SOX6 was downregulated in patients with MM and the downregulation of SOX6 was inversely correlated with that of miR-765 expression. Furthermore, SOX6 knockdown markedly abrogated the effects of miR-765 underexpression on cell proliferation and apoptosis in MM. The current study demonstrated that miR-765 serves an oncogenic role in MM progression by directly targeting SOX6, suggesting that miR-765 may be a potential therapeutic target for MM prevention and treatment.

microRNA-205 and microRNA-338-3p Reduces Cell Apoptosis in Prostate Carcinoma Tissue and LNCaP Prostate Carcinoma Cells by Directly Targeting the B-Cell Lymphoma 2 (Bcl-2) Gene

Background

The inhibitor of apoptosis, B-cell lymphoma 2 (Bcl-2), is encoded by the BCL2 gene. Previous studies have shown that microRNAs are downregulated in prostate cancer. This study aimed to investigate the role of microRNA-205 and microRNA-338-3p and cell apoptosis in prostate carcinoma tissue and the LNCaP human prostate adenocarcinoma cell line by directly targeting the BCL2 gene and Bcl-2 protein expression.

Material/Methods

Bioinformatics methods predicted the target genes of miR-205 and miR-338-3p, which were validated by a luciferase assay. Immunohistochemistry was used to detect Bcl-2 protein expression in 30 samples of prostate carcinoma tissue and 30 matched samples of normal prostate. The normal prostate epithelial cell line, RWPE-1, and LNCaP human prostate adenocarcinoma cells studied in vitro. BCL2 mRNA expression and Bcl-2 protein expression were determined by quantitative polymerase chain reaction (q-PCR) and Western blot, respectively. Cell apoptosis was measured by flow cytometry using annexin V, fluorescein isothiocyanate, and phycoerythrin (annexin V-FITC/PE).

Results

TargetScan Human 7.2 predicted that the structures of miR-205 and miR-338-3p had a binding site on the proto-oncogene, BCL2, which was verified by a luciferase assay. The expression of miR-205 and miR-338-3p were significantly downregulated in prostate carcinoma tissues and LNCaP cells when compared with normal controls. BCL2 expression was significantly inhibited by overexpression of miR-205 and miR-338-3p in LNCaP cells.

Conclusions

The results of this study showed that miR-205 and miR-338-3p downregulated the expression of the BCL2 gene and decreased apoptosis in prostate carcinoma.