miR-203 inhibits cell growth and regulates G1/S transition by targeting Bmi-1 in myeloma cells

MicroRNA-Mediated Regulation of Histone-Modifying Enzymes in Cancer: Mechanisms and Therapeutic Implications

In the past decade, significant advances in molecular research have provided a deeper understanding of the intricate regulatory mechanisms involved in carcinogenesis. MicroRNAs, short non-coding RNA sequences, exert substantial influence on gene expression by repressing translation or inducing mRNA degradation. In the context of cancer, miRNA dysregulation is prevalent and closely associated with various stages of carcinogenesis, including initiation, progression, and metastasis. One crucial aspect of the cancer phenotype is the activity of histone-modifying enzymes that govern chromatin accessibility for transcription factors, thus impacting gene expression. Recent studies have revealed that miRNAs play a significant role in modulating these histone-modifying enzymes, leading to significant implications for genes related to proliferation, differentiation, and apoptosis in cancer cells. This article provides an overview of current research on the mechanisms by which miRNAs regulate the activity of histone-modifying enzymes in the context of cancer. Both direct and indirect mechanisms through which miRNAs influence enzyme expression are discussed. Additionally, potential therapeutic implications arising from miRNA manipulation to selectively impact histone-modifying enzyme activity are presented. The insights from this analysis hold significant therapeutic promise, suggesting the utility of miRNAs as tools for the precise regulation of chromatin-related processes and gene expression. A contemporary focus on molecular regulatory mechanisms opens therapeutic pathways that can effectively influence the control of tumor cell growth and dissemination.

MicroRNA-429 Regulates Invasion and Migration of Multiple Myeloma Cells via Bmi1/AKT Pathway

Background: miR-429-mediated progression of multiple myeloma (MM) was studied through mediating B cell-specific Moloney murine leukemia virus integration site 1 (Bmi1)/protein kinase B (AKT) pathway. Methods: miRNA or siRNA was delivered into MM cell lines to alter cellular proliferation, apoptosis, invasion and migration. Measurements of miR-429 and Bmi1 levels were performed. AKT and p-AKT expression change was measured after regulating miR-429. The interaction between miR-429 and Bmi1 was analyzed. Results: miR-429 elevation disrupted proliferation, anti-apoptosis, migration and invasion properties of MM cells, and inactivated AKT pathway. Bmi1 was a targeting partner of miR-429, which was highly expressed in MM. Bmi1 knockdown phenotyped the effects of overexpressed miR-429 on MM cells. AKT agonist SC70 reversed miR-429-regulated inhibition of MM cell growth. Conclusion: miR-429 suppresses the activation of Bmi1/AKT pathway to down-regulate the malignant functions of MM cells.

The Crucial Roles of Bmi-1 in Cancer: Implications in Pathogenesis, Metastasis, Drug Resistance, and Targeted Therapies

B-cell-specific Moloney murine leukemia virus integration region 1 (Bmi-1, also known as RNF51 or PCGF4) is one of the important members of the PcG gene family, and is involved in regulating cell proliferation, differentiation and senescence, and maintaining the self-renewal of stem cells. Many studies in recent years have emphasized the role of Bmi-1 in the occurrence and development of tumors. In fact, Bmi-1 has multiple functions in cancer biology and is closely related to many classical molecules, including Akt, c-MYC, Pten, etc. This review summarizes the regulatory mechanisms of Bmi-1 in multiple pathways, and the interaction of Bmi-1 with noncoding RNAs. In particular, we focus on the pathological processes of Bmi-1 in cancer, and explore the clinical relevance of Bmi-1 in cancer biomarkers and prognosis, as well as its implications for chemoresistance and radioresistance. In conclusion, we summarize the role of Bmi-1 in tumor progression, reveal the pathophysiological process and molecular mechanism of Bmi-1 in tumors, and provide useful information for tumor diagnosis, treatment, and prognosis.

lncRNA transcription factor 7 is related to deteriorating clinical features and poor prognosis in multiple myeloma, and its knockdown suppresses disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway

Multiple myeloma (MM) remains a challenge to treat, and its precise pathogenic mechanisms have not been fully clarified. The present study aimed to evaluate the relation between long non-coding RNA transcription factor 7 (lnc-TCF7) and clinical features, as well as the prognosis of patients with MM, and to determine the effects of lnc-TCF7-knockdown on the regulation (and regulatory mechanisms) of MM progression. lnc-TCF7 expression was detected in the bone marrow plasma cells of 86 patients with MM and 30 healthy controls. In patients with MM, the clinical data were collected, and event-free survival (EFS) and overall survival (OS) analyses were conducted. In vitro, lnc-TCF7 expression was detected in MM cell lines and normal bone marrow plasma cells. Using Roswell Park Memorial Institute 8226 cells, functional experiments were conducted following lnc-TCF7 short hairpin (sh)RNA transfection, and compensation experiments were performed after lnc-TCF7 shRNA transfection alone and in combination with a microRNA (miR)-203 inhibitor. lnc-TCF7 expression was increased in patients with MM compared with the healthy controls and was positively related to β-2-microglobulin expression and International Staging System stage, while negatively associated with complete response, EFS and OS. In vitro, lnc-TCF7 was upregulated in MM cells compared with normal bone marrow plasma cells, and its knockdown suppressed MM cell proliferation while promoting apoptosis. Compensation experiments showed that miR-203 inhibition promoted MM progression by regulating the Jagged1-Notch1 signaling pathway in lnc-TCF7-knockdown cells. In conclusion, increased lnc-TCF7 expression was related to deteriorating clinical features and prognosis, and lnc-TCF7-knockdown inhibited disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway activation in MM.

COTI-2 induces cell apoptosis in pediatric acute lymphoblastic leukemia via upregulation of miR-203

COTI-2 is a third-generation thiosemicarbazone, which is effective against a diverse group of human cancer cell lines at nanomolar concentrations. COTI-2 also showed superior activity against tumor cells, in vitro and in vivo. As a high efficacy and low toxicity agent, it currently candidates in a phase I clinical study of gynecological malignancies and head and neck squamous cell carcinoma (HNSCC). However, its effect in pediatric T-cell acute lymphoblastic leukemia (T-ALL) is not clear. This study investigates the effect of COTI-2 on T-ALL Jurkat cells in vitro and in vivo. Jurkat cells were exposure to COTI-2 at different concentration and time. Cell apoptosis was detected by flow cytometry to examine the sensitivity of Jurkat cell lines treated with either COTI-2 alone or in combination with MiR-203 mimic or inhibitor in vitro. An orthotopic mouse model was used to examine the sensitivity of Jurkat cells treated with COTI-2 in vivo. Western blotting and RT-qPCR were performed to dissect molecular mechanisms. The results showed that COTI-2 promotes apoptosis of Jurkat cells in dose-and time-dependent way. Enforced expression of miR-203 promotes COTI-2-mediated cell apoptosis, whereas miR-203 silencing attenuates COTI-2-mediated cell apoptosis in Jurkat cells in vitro. COTI-2 is also effective against growth of Jurkat cells in vivo. Mechanistically, COTI-2 induced miR-203 upregulation and inhibited caspase-3/9 activaty leading to inhibition of cell apoptosis. Taken together, COTI-2 inhibits tumor growth in vitro and in vivo in Jurkat cells likely through miR-203-dependent mechanisms. COTI-2 may be a potential approach for T-ALL treatment.

Role of Polycomb Complexes in Normal and Malignant Plasma Cells

Plasma cells (PC) are the main effectors of adaptive immunity, responsible for producing antibodies to defend the body against pathogens. They are the result of a complex highly regulated cell differentiation process, taking place in several anatomical locations and involving unique genetic events. Pathologically, PC can undergo tumorigenesis and cause a group of diseases known as plasma cell dyscrasias, including multiple myeloma (MM). MM is a severe disease with poor prognosis that is characterized by the accumulation of malignant PC within the bone marrow, as well as high clinical and molecular heterogeneity. MM patients frequently develop resistance to treatment, leading to relapse. Polycomb group (PcG) proteins are epigenetic regulators involved in cell fate and carcinogenesis. The emerging roles of PcG in PC differentiation and myelomagenesis position them as potential therapeutic targets in MM. Here, we focus on the roles of PcG proteins in normal and malignant plasma cells, as well as their therapeutic implications.

MicroRNA-498 inhibits the proliferation, migration and invasion of gastric cancer through targeting BMI-1 and suppressing AKT pathway

Recently, microRNA-498 (miR-498) plays important effect in human cancers. Nonetheless, the role of miR-498 is still unclear in gastric cancer (GC). Therefore, this study was designed to investigate the function of miR-498 in GC tissues and cell lines (SGC-7901, BGC-823, MGC-803). The expressions of miR-498 and BMI-1 were examined in GC tissues via the RT-qPCR assay. The function of miR-498 was investigated through MTT and transwell assays. The relationship between miR-498 and BMI-1 was testified by dual luciferase assay. The protein expression of EMT markers, AKT pathway markers and BMI-1 was measured through western blot. The expression of miR-498 was decreased in GC tissues which predicted poor prognosis of GC patients. Moreover, functional analyses show that the overexpression of miR-498 inhibited the progression of GC. Furthermore, BMI-1 was a direct target of miR-498 which was upregulated in GC. Especially, the upregulation of BMI-1 recovered the suppressive effect of miR-498 in GC. In addition, miR-498 inhibited the metastasis and proliferation of GC cells through blocking EMT and AKT pathway. MiR-498, by targeting BMI-1, presents a plethora of tumor suppressor activities in GC cells.

miR-124 and miR-203 synergistically inactivate EMT pathway via coregulation of ZEB2 in clear cell renal cell carcinoma (ccRCC)

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is one of the most aggressive urological malignancies. MicroRNAs (miRNAs) are post-transcriptional gene regulators in tumor pathophysiology. As miRNAs exert cooperative repressive effects on target genes, studying the miRNA synergism is important to elucidate the regulation mechanism of miRNAs.

METHODS

We first created a miRNA-mRNA association network based on sequence complementarity and co-expression patterns of miRNA-targets. The synergism between miRNAs was then defined based on their expressional coherence and the concordance between target genes. The miRNA and mRNA expression were detected in RCC cell lines (786-O) using quantitative RT-PCR. Potential miRNA-target interaction was identified by Dual-Luciferase Reporter assay. Cell proliferation and migration were assessed by CCK-8 and transwell assay.

RESULTS

A synergistic miRNA-miRNA interaction network of 28 miRNAs (52 miRNA pairs) with high coexpression level were constructed, among which miR-124 and miR-203 were identified as most tightly connected. ZEB2 expression is inversely correlated with miR-124 and miR-203 and verified as direct miRNA target. Cotransfection of miR-124 and miR-203 into 786-O cell lines effectively attenuated ZEB2 level and normalized renal cancer cell proliferation and migration. The inhibitory effects were abolished by ZEB2 knockdown. Furthermore, pathway analysis suggested that miR-124 and miR-203 participated in activation of epithelial-to-mesenchymal transition (EMT) pathway via regulation of ZEB2.

CONCLUSIONS

Our findings provided insights into the role of miRNA-miRNA collaboration as well as a novel therapeutic approach in ccRCC.

CBX4 promotes the proliferation and metastasis via regulating BMI-1 in lung cancer

Proliferation and metastasis are significantly malignant characteristics of human lung cancer, but the underlying molecular mechanisms are poorly understood. Chromobox 4 (CBX4), a member of the Polycomb group (PcG) family of epigenetic regulatory factors, enhances cellular proliferation and promotes cancer cell migration. However, the effect of CBX4 in the progression of lung cancer is not fully understood. We found that CBX4 is highly expressed in lung tumours compared with adjacent normal tissues. Overexpression of CBX4 significantly promotes cell proliferation and migration in human lung cancer cell lines. The knockdown of CBX4 obviously suppresses the cell growth and migration of human lung cancer cells in vitro. Also, the proliferation and metastasis in vivo are blocked by CBX4 knockdown. Furthermore, CBX4 knockdown effectively arrests cell cycle at the G0/G1 phase through suppressing the expression of CDK2 and Cyclin E and decreases the formation of filopodia through suppressing MMP2, MMP9 and CXCR4. Additionally, CBX4 promotes proliferation and metastasis via regulating the expression of BMI-1 which is a significant regulator of proliferation and migration in lung cancer cells. Taken together, these data suggest that CBX4 is not only a novel prognostic marker but also may be a potential therapeutic target in lung cancer.

Targeting of stromal versican by miR-144/199 inhibits multiple myeloma by downregulating FAK/STAT3 signalling

The abnormal growth of malignant plasma cells in Multiple Myeloma (MM) requires bone marrow (BM) niche consisting of proteoglycans, cytokines, etc. Versican (VCAN), a chondroitin sulphate proteoglycan promotes progression in solid tumours but there is dearth of literature in MM. Hence, we studied the involvement of VCAN in MM and its regulation by microRNAs as a therapeutic approach. Thirty MM patients and 20 controls were recruited and BM stromal cells (BMSCs) were isolated by primary culture. Molecular levels of VCAN, miR-144, miR-199 & miR-203 were determined in study subjects and cell lines. The involvement of VCAN in myeloma pathogenesis was studied using BMSCs-conditioned medium (BMSCs-CM) and VCAN-neutralizing antibody or microRNA mimics. Elevated expression of VCAN was observed in patients especially in BM stroma while microRNA expression was significantly lower and showed negative correlation with VCAN. Moreover, BMSCs-CM showed the presence of VCAN which upon supplementing to MM cells alter parameters in favour of myeloma progression, however, this effect was neutralized by VCAN antibody or miR (miR-144 and miR-199) mimics. The downstream signalling of VCAN was found to activate FAK and STAT3 which subsides by using VCAN antibody or miR mimics. The neutralization of oncogenic effect of BMSCs-CM by VCAN blockage affirms its plausible role in progression of MM. VCAN was observed as a paracrine mediator in the cross-talk of BMSCs and myeloma cells in BM microenvironment. Therefore, these findings suggest exploring VCAN as novel therapeutic target and utilization of microRNAs as a therapy to regulate VCAN for better management of MM.

Effective Delivery of a Microtubule Polymerization Inhibitor Synergizes with Standard Regimens in Models of Pancreatic Ductal Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDA) is a deadly cancer that is broadly chemoresistant, due in part to biophysical properties of tumor stroma, which serves as a barrier to drug delivery for most classical chemotherapeutic drugs. The goal of this work is to evaluate the preclinical efficacy and mechanisms of PTC596, a novel agent with potent anticancer properties in vitro and desirable pharmacologic properties in vivo.Experimental Design: We assessed the pharmacology, mechanism, and preclinical efficacy of PTC596 in combination with standards of care, using multiple preclinical models of PDA.

RESULTS

We found that PTC596 has pharmacologic properties that overcome the barrier to drug delivery in PDA, including a long circulating half-life, lack of P-glycoprotein substrate activity, and high systemic tolerability. We also found that PTC596 combined synergistically with standard clinical regimens to improve efficacy in multiple model systems, including the chemoresistant genetically engineered "KPC" model of PDA. Through mechanistic studies, we learned that PTC596 functions as a direct microtubule polymerization inhibitor, yet a prior clinical trial found that it lacks peripheral neurotoxicity, in contrast to other such agents. Strikingly, we found that PTC596 synergized with the standard clinical backbone regimen gemcitabine/nab-paclitaxel, yielding potent, durable regressions in a PDX model. Moreover, similar efficacy was achieved in combination with nab-paclitaxel alone, highlighting a specific synergistic interaction between two different microtubule-targeted agents in the setting of pancreatic ductal adenocarcinoma.

CONCLUSIONS

These data demonstrate clear rationale for the development of PTC596 in combination with standard-of-care chemotherapy for PDA.

Clinical significance of circulatory microRNA-203 in serum as novel potential diagnostic marker for multiple myeloma

PURPOSE

Multiple myeloma (MM) is a hematological malignancy marked by uncontrolled proliferation and accumulation of plasma cells in bone marrow. Despite presence of numerous diagnostic markers for MM, their invasive and non-specific nature demands identification of some effective biomarker. Small non-coding RNAs, i.e., microRNAs being secreted out in circulation could depict the change in homeostasis. Earlier, we reported diagnostic potential of a proteoglycan, Versican (VCAN) in MM, hence, VCAN linked cell-free microRNAs have been explored to study their diagnostic involvement in MM.

METHODS

Biopsy proven MM patients and controls were recruited. The relative microRNA expression of VCAN linked microRNAs (miR-143, miR-144, miR-199, and miR-203) along with levels of VCAN have been investigated in bone marrow supernatant fluid (BMSF) and blood serum and their correlation were done with clinico-pathological parameters. The diagnostic potential was assessed using ROC curve.

RESULTS

Relative microRNA expression of all microRNAs was found significantly lower in MM patients in both BMSF and serum while VCAN levels were substantially higher in patients. VCAN levels showed positive trend while microRNAs expression showed negative trend with severity of disease. miR-203 showed significant correlation with myeloma-associated parameters and also showed optimum sensitivity and specificity for diagnosis of MM in serum.

CONCLUSIONS

Downregulation of cell-free microRNAs illustrates their importance in MM. The negative trend of microRNAs with disease progression suggests their diagnostic significance. Correlation of miR-203 with myeloma clinical parameters along with optimum sensitivity and specificity affirms its non-invasive diagnostic potential in MM which could further be validated in larger patient cohort.

Identification of key pathways and genes in endometrial cancer using bioinformatics analyses

Endometrial cancer (EC) is one of the most common gynecological cancer types worldwide. However, to the best of our knowledge, its underlying mechanisms remain unknown. The current study downloaded three mRNA and microRNA (miRNA) datasets of EC and normal tissue samples, GSE17025, GSE63678 and GSE35794, from the Gene Expression Omnibus to identify differentially expressed genes (DEGs) and miRNAs (DEMs) in EC tumor tissues. The DEGs and DEMs were then validated using data from The Cancer Genome Atlas and subjected to gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. STRING and Cytoscape were used to construct a protein-protein interaction network and the prognostic effects of the hub genes were analyzed. Finally, miRecords was used to predict DEM targets and an miRNA-gene network was constructed. A total of 160 DEGs were identified, of which 51 genes were highly expressed and 100 DEGs were discovered from the PPI network. Three overlapping genes between the DEGs and the DEM targets, BIRC5, CENPF and HJURP, were associated with significantly worse overall survival of patients with EC. A number of DEGs were enriched in cell cycle, human T-lymphotropic virus infection and cancer-associated pathways. A total of 20 DEMs and 29 miRNA gene pairs were identified. In conclusion, the identified DEGs, DEMs and pathways in EC may provide new insights into understanding the underlying molecular mechanisms that facilitate EC tumorigenesis and progression.

BMI1 and PTEN are key determinants of breast cancer therapy: A plausible therapeutic target in breast cancer

BMI-1 (B-lymphoma Mo-MLV insertion region 1) is a key protein partner in polycomb repressive complex 1 (PRC1) that helps in maintaining the integrity of the complex. It is also a key player in ubiquitination of histone H2A which affects gene expression pattern involved in various cellular processes such as cell proliferation, growth, DNA repair, apoptosis and senescence. In many cancers, Overexpression of BMI1correlates with advanced stages of disease, aggressive clinicopathological behavior, poor prognosis resistance to radiation and chemotherapy. BMI1 is emerging as a key player in EMT, chemo-resistance and cancer stemness. Overexpression is observed in various cancer types such as breast, primary hepatocellular carcinoma (HCC), gastric, ovarian, head and neck, pancreatic and lung cancer. Studies have shown that experimental reduction of BMI protein level in tumor cells results in inhibition of cell proliferation, induction of apoptosis and/or senescence, and increases susceptibility to cytotoxic agents and radiation therapy. Thus, inhibition of BMI1 expression particularly in breast cancer stem cells can be used as a potential strategy for the complete elimination of tumor and to prevent disease relapse. On other hand PTEN is known to be an important tumor suppressor next to p53. In many cancers particularly in breast cancer, p53 and PTEN undergo mutations. Studies have indicated the functional and mechanistic link between the BMI-1oncoprotein and tumor suppressor PTEN in the development and progression of cancer. The current review focuses on recent findings of how oncogenicity and chemo-resistance are caused by BMI1. It also highlights the transcriptional regulation between BMI1 and PTEN that dictates the therapeutic outcome in cancers where the functional p53 is absent. Herein, we have clearly demonstrated the regulation of transcription at genomic loci of BMI1 and PTEN in cancerous tissue or cells and the possible epigenetic regulation by histone deacetylase inhibitors (HDACi) at BMI1 and PTEN loci that may provide some clue for the possible therapy against TNBC in near future.

Epigenetics and MicroRNAs in Cancer

The ability to reprogram the transcriptional circuitry by remodeling the three-dimensional structure of the genome is exploited by cancer cells to promote tumorigenesis. This reprogramming occurs because of hereditable chromatin chemical modifications and the consequent formation of RNA-protein-DNA complexes that represent the principal actors of the epigenetic phenomena. In this regard, the deregulation of a transcribed non-coding RNA may be both cause and consequence of a cancer-related epigenetic alteration. This review summarizes recent findings that implicate microRNAs in the aberrant epigenetic regulation of cancer cells.

MiR-203 Participates in Human Placental Angiogenesis by Inhibiting VEGFA and VEGFR2 Expression

Angiogenesis during placentation is of great significance in maintaining normal pregnancy. However, the molecular mechanisms of this process are not clear. It has been reported that miR-203 plays a critical role in the development and progression of many tumors but not focused on the relationship between miR-203 and placental angiogenesis. The present study aims to illustrate the correlation between miR-203 and vascular endothelial growth factor (VEGFA)/vascular endothelial growth factor receptors 2 (VEGFR2) in human placenta and human umbilical vein endothelial cells (HUVECs) obtained from 40 samples. Samples of human placenta were collected based on gestation age, which was divided into early preterm (n = 10), late preterm (n = 12), and term (n = 18). In this work, we demonstrated that the expression of miR-203 decreased significantly in the placenta according to the gestation age, in contrast, the expression of VEGFA and VEGFR2 increased accordingly. In vitro experiments revealed that overexpression of miR-203 not only suppressed the proliferation, migration, invasion, and tube formation of HUVECs but also affected the expression of VEGFA and VEGFR2. Furthermore, inhibition of miR-203 expression showed equally apparent positive effects on HUVECs. In conclusion, our study suggests that miR-203 plays an important role in regulating placental angiogenesis through inhibiting the expression of VEGFA and VEGFR2, thus miR-203 may represent a potential therapeutic target for patients with abnormal formation of blood vessels in the placenta.

Identification and profiling of growth-related microRNAs in Chinese perch (Siniperca chuatsi)

Background

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play important roles in the regulation of diverse biological processes in eukaryotes. Chinese perch (Siniperca chuatsi) is one of the most economically important fish species widely cultured in China. Growth is an extremely important characteristic in fish. Individual differences in body size are common in Siniperca chuatsi, which significantly influence the aquaculture production of Siniperca chuatsi. However, the underline growth-related regulatory factors, such as miRNAs, are still unknown.

Results

To investigate the growth-related miRNAs in Siniperca chuatsi, two RNA libraries from four growth-related tissues (brain, pituitary, liver, and muscle) of Siniperca chuatsi at 6-month stage with relatively high or low growth rates (big-size group or small-size group) were obtained and sequenced using Solexa sequencing. A total of 252 known miRNAs and 12 novel miRNAs were identified. The expression patterns of these miRNAs in big-size group and small-size group were compared, and the results showed that 31 known and 5 novel miRNAs were differently expressed (DE). Furthermore, to verify the Solexa sequencing, five DE miRNAs were randomly selected and quantified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The results showed that their expression patterns were consistent with those of Solexa sequencing. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of target genes of DE miRNAs was performed. It showed that the target genes were involved in multiple biological processes including metabolic process, suggesting that metabolic process played an important role in growth of fish.

Conclusions

Siniperca chuatsi is a popular and economically important species in aquaculture. In this study, miRNAs in Siniperca chuatsi with different growth rates were identified, and their expression profiles were compared. The data provides the first large-scale miRNA profiles related to growth of Siniperca chuatsi, which is expected to contribute to a better understanding of the role of miRNAs in regulating the biological processes of growth and possibly useful for Siniperca chuatsi breeding.

Electronic supplementary material

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