miRNA-130a targets ATG2B and DICER1 to inhibit autophagy and trigger killing of chronic lymphocytic leukemia cells

MicroRNA-mediated autophagy and drug resistance in cancer: mechanisms and therapeutic strategies

This paper provides an exhaustive overview of the intricate interplay between microRNAs (miRNAs) and autophagy in the context of human cancers, underscoring the pivotal role these non-coding RNAs play in modulating autophagic pathways and their implications for cancer development, progression, and resistance to therapy. MiRNAs, as critical regulators of gene expression post-transcription, influence various biological processes, including autophagy, a catabolic mechanism essential for cellular homeostasis, stress response, and survival. The review meticulously delineates the mechanisms through which miRNAs impact autophagy by targeting specific genes and signaling pathways, thereby affecting cancer cell proliferation, metastasis, and response to chemotherapy. It highlights several miRNAs with dual roles, acting either as oncogenes or tumor suppressors based on the cellular context and the specific autophagic pathways they regulate. The paper further explores the therapeutic potential of targeting miRNA-autophagy axis, offering insights into novel strategies for cancer treatment through modulation of this axis. Emphasizing the complexity of the miRNA-autophagy relationship, the review calls for more in-depth studies to unravel the nuanced regulatory networks between miRNAs and autophagy in cancer, which could pave the way for the development of innovative therapeutic interventions and diagnostic tools.

Study on the mechanism of miR-7562 regulating ATG5 and ATG12 genes in Penaeus monodon under Vibrio harveyi infection

MicroRNAs (miRNAs) play a fundamental role in the post-transcriptional regulation of genes and are pivotal in modulating immune responses in marine species, particularly during pathogen assaults. This study focused on the function of miR-7562 and its regulatory effects on autophagy against Vibrio harveyi infection in the black tiger shrimp (Penaeus monodon), an economically important aquatic species. We successfully cloned and characterized two essential autophagy-related genes (ATGs) from P. monodon, PmATG5 and PmATG12, and then identified the miRNAs potentially involved in co-regulating these genes, which were notably miR-7562, miR-8485, and miR-278. Subsequent bacterial challenge experiments and dual-luciferase reporter assays identified miR-7562 as the principal regulator of both genes, particularly by targeting the 3'UTR of each gene. By manipulating the in vivo levels of miR-7562 using mimics and antagomirs, we found significant differences in the expression of PmATG5 and PmATG12, which corresponded to alterations in autophagic activity. Notably, miR-7562 overexpression resulted in the downregulation of PmATG5 and PmATG12, leading to a subdued autophagic response. Conversely, miR-7562 knockdown elevated the expression levels of these genes, thereby enhancing autophagic activity. Our findings further revealed that during V. harveyi infection, miR-7562 continued to influence the autophagic pathway by specifically targeting the ATG5-ATG12 complex. This research not only sheds light on the miRNA-dependent mechanisms governing autophagic immunity in shrimp but also proposes miR-7562 as a promising target for therapeutic strategies intended to strengthen disease resistance within the crustacean aquaculture industry.

Additional prognostic value of polymorphisms within the 3'-untranslated region of programmed cell death pathway genes in early-stage breast cancer

Introduction

The programmed cell death (PCD) pathway plays an important role in restricting cancer cell survival and proliferation. However, limited studies have investigated the association between genetic variants in the 3'-untranslated region of the PCD pathway genes and breast cancer outcomes.

Methods

In this study, we genotyped 28 potentially functional single nucleotide polymorphisms (SNPs) in 23 PCD pathway genes in 1,177 patients with early-stage breast cancer (EBC) from a Han Chinese population. The median follow-up period was 174 months.

Results

Among all the candidate SNPs, four independent SNPs (rs4900321 and rs7150025 in ATG2B, rs6753785 in BCL2L11, and rs2213181 in c-Kit) were associated with invasive disease-free survival (iDFS), distant disease-free survival (DDFS), breast cancer-specific survival (BCSS) and overall survival (OS), respectively. Further combined genotypes of these four SNPs revealed that the survival decreased as the number of unfavorable genotypes increased (Ptrend = 1.0 × 10-6, 8.5 × 10-8, 3.6 × 10-4, and 1.3 × 10-4 for iDFS, DDFS, BCSS, and OS, respectively). Receiver operating characteristic curve analysis demonstrated that incorporating unfavorable genotypes and clinicopathological variables improved the ability to predict EBC survival (P = 0.006, 0.004, 0.029, and 0.019 for iDFS, DDFS, BCSS, and OS, respectively). Additionally, rs6753785 and rs2213181 were associated with BCL2L11 and c-Kit mRNA expression, respectively.

Conclusions

Our results suggest that these four SNPs may act as novel biomarkers for EBC survival, possibly by modulating the expression of the corresponding genes.

Molecular mechanisms in regulation of autophagy and apoptosis in view of epigenetic regulation of genes and involvement of liquid-liquid phase separation

Cellular physiology is critically regulated by multiple signaling nexuses, among which cell death mechanisms play crucial roles in controlling the homeostatic landscape at the tissue level within an organism. Apoptosis, also known as programmed cell death, can be induced by external and internal stimuli directing the cells to commit suicide in unfavourable conditions. In contrast, stress conditions like nutrient deprivation, infection and hypoxia trigger autophagy, which is lysosome-mediated processing of damaged cellular organelle for recycling of the degraded products, including amino acids. Apparently, apoptosis and autophagy both are catabolic and tumor-suppressive pathways; apoptosis is essential during development and cancer cell death, while autophagy promotes cell survival under stress. Moreover, autophagy plays dual role during cancer development and progression by facilitating the survival of cancer cells under stressed conditions and inducing death in extreme adversity. Despite having two different molecular mechanisms, both apoptosis and autophagy are interconnected by several crosslinking intermediates. Epigenetic modifications, such as DNA methylation, post-translational modification of histone tails, and miRNA play a pivotal role in regulating genes involved in both autophagy and apoptosis. Both autophagic and apoptotic genes can undergo various epigenetic modifications and promote or inhibit these processes under normal and cancerous conditions. Epigenetic modifiers are uniquely important in controlling the signaling pathways regulating autophagy and apoptosis. Therefore, these epigenetic modifiers of both autophagic and apoptotic genes can act as novel therapeutic targets against cancers. Additionally, liquid-liquid phase separation (LLPS) also modulates the aggregation of misfolded proteins and provokes autophagy in the cytosolic environment. This review deals with the molecular mechanisms of both autophagy and apoptosis including crosstalk between them; emphasizing epigenetic regulation, involvement of LLPS therein, and possible therapeutic approaches against cancers.

Epigenetic Regulation of Autophagy in Bone Metabolism

The skeletal system is crucial for supporting bodily functions, protecting vital organs, facilitating hematopoiesis, and storing essential minerals. Skeletal homeostasis, which includes aspects such as bone density, structural integrity, and regenerative processes, is essential for normal skeletal function. Autophagy, an intricate intracellular mechanism for degrading and recycling cellular components, plays a multifaceted role in bone metabolism. It involves sequestering cellular waste, damaged proteins, and organelles within autophagosomes, which are then degraded and recycled. Autophagy's impact on bone health varies depending on factors such as regulation, cell type, environmental cues, and physiological context. Despite being traditionally considered a cytoplasmic process, autophagy is subject to transcriptional and epigenetic regulation within the nucleus. However, the precise influence of epigenetic regulation, including DNA methylation, histone modifications, and non-coding RNA expression, on cellular fate remains incompletely understood. The interplay between autophagy and epigenetic modifications adds complexity to bone cell regulation. This article provides an in-depth exploration of the intricate interplay between these two regulatory paradigms, with a focus on the epigenetic control of autophagy in bone metabolism. Such an understanding enhances our knowledge of bone metabolism-related disorders and offers insights for the development of targeted therapeutic strategies.

Regulatory miRNAs in cancer cell recovery from therapy exposure and its implications as a novel therapeutic strategy for preventing disease recurrence

The desired outcome of cancer therapies is the eradication of disease. This can be achieved when therapy exposure leads to therapy-induced cancer cell death as the dominant outcome. Theoretically, a permanent therapy-induced growth arrest could also contribute to a complete response, which has the potential to lead to remission. However, preclinical models have shown that therapy-induced growth arrest is not always durable, as recovering cancer cell populations can contribute to the recurrence of cancer. Significant research efforts have been expended to develop strategies focusing on the prevention of recurrence. Recovery of cells from therapy exposure can occur as a result of several cell stress adaptations. These include cytoprotective autophagy, cellular quiescence, a reversable form of senescence, and the suppression of apoptosis and necroptosis. It is well documented that microRNAs regulate the response of cancer cells to anti-cancer therapies, making targeting microRNAs therapeutically a viable strategy to sensitization and the prevention of recovery. We propose that the use of microRNA-targeting therapies in prolonged sequence, that is, a significant period after initial therapy exposure, could reduce toxicity from the standard combination strategy, and could exploit new epigenetic states essential for cancer cells to recover from therapy exposure. In a step toward supporting this strategy, we survey the available scientific literature to identify microRNAs which could be targeted in sequence to eliminate residual cancer cell populations that were arrested as a result of therapy exposure. It is our hope that by successfully identifying microRNAs which could be targeted in sequence we can prevent disease recurrence.

Ginsenoside Rg1 attenuates the NASH phenotype by regulating the miR-375-3p/ATG2B/PTEN-AKT axis to mediate autophagy and pyroptosis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is one of the most frequent liver diseases at present, and there is no radical treatment. The consequences of a variety of ginsenoside compounds on this situation have before been reported, however, the specific effect on the monomeric ginsenoside Rg1 (Rg1) and its associated underlying molecular mechanism stay unknown.

MATERIAL AND METHODS

In vitro, the cell models were constructed by exposing free fatty acids (FFAs) to HepG2 cells. A methionine and choline deficiency (MCD)-induced NASH mouse model was also established over 5-6 weeks of treatment. Rg1 is a traditional Chinese medicine monomer. These NASH models were treated with Rg1 and analyzed by qRT-PCR, Western Blot, sequencing, Oil red O staining, immunofluorescence, enzyme activity, HE staining, ELISA, double luciferase reporter assay, and immunohistochemistry.

RESULTS

Overexpression of ATG2B, an autophagy-related protein, attenuated lipid droplet accumulation and reduces ALT, AST, inflammatory cytokines, hydrogen peroxide, and pyroptosis in established mouse and cellular models of NASH and increased levels of ATP and autophagy. The binding sites of miR-375-3p and ATG2B were verified by bioinformatic prediction and a dual-luciferase reporter gene. Knockdown of miR-375-3p promoted autophagy and inhibited pyroptosis. ATG2B knockdown substantially attenuated the impact of miR-375-3p on NASH. Rg1 appears to regulate the occurrence and development of NASH inflammation through miR-375-3p and ATG2B in vitro and in vivo, and is regulated by PTEN-AKT pathway.

CONCLUSIONS

This study showed that Rg1 participates in autophagy and pyroptosis through the miR-375-3p/ATG2B/PTEN-AKT pathway, thereby alleviating the occurrence and development of NASH, for that reason revealing Rg1 as a candidate drug for NASH.

The Role of microRNAs in Regulating Cancer Cell Response to Oxaliplatin-Containing Regimens

Oxaliplatin (cyclohexane-1,2-diamine; oxalate; platinum [2+]) is a third-generation chemotherapeutic drug with anticancer effects. Oxaliplatin has a role in the treatment of several cancers. It is one of the few drugs which can eliminate the neoplastic cells of colorectal cancer. Also, it has an influential role in breast cancer, lung cancer, bladder cancer, prostate cancer, and gastric cancer. Although oxaliplatin has many beneficial effects in cancer treatment, resistance to this drug is in the way to cure neoplastic cells and reduce treatment efficacy. microRNAs are a subtype of small noncoding RNAs with ∼22 nucleotides that exist among species. They have diverse roles in physiological processes, including cellular proliferation and cell death. Moreover, miRNAs have essential roles in resistance to cancer treatment and can strengthen sensitivity to chemotherapeutic drugs and regimens. In colorectal cancer, the co-treatment of oxaliplatin with anti-miR-19a can partially reverse the oxaliplatin resistance through the upregulation of phosphatase and tensin homolog (PTEN). Moreover, by preventing the spread of gastric cancer cells and downregulating glypican-3 (GPC3), MiR-4510 may modify immunosuppressive signals in the tumor microenvironment. Treatment with oxaliplatin may develop into a specialized therapeutic drug for patients with miR-4510 inhibition and glypican-3-expressing gastric cancer. Eventually, miR-122 upregulation or Wnt/β-catenin signaling suppression boosted the death of HCC cells and made them more sensitive to oxaliplatin. Herein, we have reviewed the role of microRNAs in regulating cancer cells' response to oxaliplatin, with particular attention to gastrointestinal cancers. We also discussed the role of these noncoding RNAs in the pathophysiology of oxaliplatin-induced neuropathic pain.

The imminent role of microRNAs in salivary adenoid cystic carcinoma

Unfortunately, despite the severe problem associated with salivary adenoid cystic carcinoma (SACC), it has not been studied in detail yet. Therefore, the time has come to understand the oncogenic cause of SACC and find the correct molecular markers for diagnosis, prognosis, and therapeutic target to tame this disease. Recently, we and others have suggested that non-coding RNAs, specifically microRNAs and long non-coding RNAs, can be ideal biomarkers for cancer(s) diagnosis and progression. Herein, we have shown that various miRNAs, like miR-155, miR‑103a‑3p, miR-21, and miR-130a increase the oncogenesis process, whereas some miRNAs such as miR-140-5p, miR-150, miR-375, miR-181a, miR-98, miR-125a-5p, miR-582-5p, miR-144-3p, miR-320a, miR-187 and miR-101-3p, miR-143-3p inhibit the salivary adenoid cystic carcinoma progression. Furthermore, we have found that miRNAs also target many vital genes and pathways like mitogen-activated protein kinases-snail family transcriptional repressor 2 (MAPK-Snai2), p38/JNK/ERK, forkhead box C1 protein (FOXC1), mammalian target of rapamycin (mTOR), integrin subunit beta 3 (ITGB3), epidermal growth factor receptor (EGFR)/NF-κB, programmed cell death protein 4 (PDCD4), signal transducer and activator of transcription 3 (STAT3), neuroblastoma RAS (N-RAS), phosphatidylinositol-3-kinase (PI3K)/Akt, MEK/ERK, ubiquitin-like modifier activating enzyme 2 (UBA2), tumor protein D52 (TPD52) which play a crucial role in the regulation of salivary adenoid cystic carcinoma. Therefore, we believe that knowledge from this manuscript will help us find the pathogenesis process in salivary adenoid cystic carcinoma and could also give us better biomarkers of diagnosis and prognosis of the disease.

MicroRNAs and the Diagnosis of Childhood Acute Lymphoblastic Leukemia: Systematic Review, Meta-Analysis and Re-Analysis with Novel Small RNA-Seq Tools

Simple Summary

MicroRNAs (miRNAs) have been under the spotlight for the last three decades. These non-coding RNAs seem to be dynamic regulators of mRNA stability and translation, in addition to interfering with transcription. Circulating miRNAs play a critical role in cell-to-cell interplay; therefore, they can serve as disease biomarkers. Meta-analysis of published data revealed that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against acute lymphoblastic leukemia (ALL) in children. Reanalysis of small RNA-seq data with novel tools identified significantly overexpressed members of the miR-128, miR-181, miR-130 and miR-17 families and significantly lower expression of miR-30, miR-24-2 and miR143~145 clusters, miR-574 and miR-618 in pediatric T-ALL cases compared with controls. Inconsistencies in methodology and study designs in most published material preclude reproducibility, and further cohort studies need to be conducted in order to empower novel tools, such as ALLSorts and RNAseqCNV.

Abstract

MicroRNAs (miRNAs) have been implicated in childhood acute lymphoblastic leukemia (ALL) pathogenesis. We performed a systematic review and meta-analysis of miRNA single-nucleotide polymorphisms (SNPs) in childhood ALL compared with healthy children, which revealed (i) that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against ALL occurrence in children; (ii) no significant association between rs2910164 genotypes in miR-146a and childhood ALL; and (iii) SNPs in DROSHA, miR-449b, miR-938, miR-3117 and miR-3689d-2 genes seem to be associated with susceptibility to B-ALL in childhood. A review of published literature on differential expression of miRNAs in children with ALL compared with controls revealed a significant upregulation of the miR-128 family, miR-130b, miR-155, miR-181 family, miR-210, miR-222, miR-363 and miR-708, along with significant downregulation of miR-143 and miR-148a, seem to have a definite role in childhood ALL development. MicroRNA signatures among childhood ALL subtypes, along with differential miRNA expression patterns between B-ALL and T-ALL cases, were scrutinized. With respect to T-ALL pediatric cases, we reanalyzed RNA-seq datasets with a robust and sensitive pipeline and confirmed the significant differential expression of hsa-miR-16-5p, hsa-miR-19b-3p, hsa-miR-92a-2-5p, hsa-miR-128-3p (ranked first), hsa-miR-130b-3p and -5p, hsa-miR-181a-5p, -2-3p and -3p, hsa-miR-181b-5p and -3p, hsa-miR-145-5p and hsa-miR-574-3p, as described in the literature, along with novel identified miRNAs.

miRNAs in Lymphocytic Leukaemias-The miRror of Drug Resistance

Refractory disease and relapse remain the main causes of cancer therapy failure. Refined risk stratification, treatment regimens and improved early diagnosis and detection of minimal residual disease have increased cure rates in malignancies like childhood acute lymphoblastic leukaemia (ALL) to 90%. Nevertheless, overall survival in the context of drug resistance remains poor. The regulatory role of micro RNAs (miRNAs) in cell differentiation, homeostasis and tumorigenesis has been under extensive investigation in different cancers. There is accumulating data demonstrating the significance of miRNAs for therapy outcomes in lymphoid malignancies and some direct demonstrations of the interplay between these small molecules and drug response. Here, we summarise miRNAs' impact on chemotherapy resistance in adult and paediatric ALL and chronic lymphocytic leukaemia (CLL). The main focus of this review is on the modulation of particular signaling pathways like PI3K-AKT, transcription factors such as NF-κB, and apoptotic mediators, all of which are bona fide and pivotal elements orchestrating the survival of malignant lymphocytic cells. Finally, we discuss the attractive strategy of using mimics, antimiRs and other molecular approaches pointing at miRNAs as promising therapeutic targets. Such novel strategies to circumvent ALL and CLL resistance networks may potentially improve patients' responses and survival rates.

Autophagy inhibits cancer stemness in triple-negative breast cancer via miR-181a-mediated regulation of ATG5 and/or ATG2B

Autophagy has a dual role in the maintenance of cancer stem cells (CSCs), but the precise relationship between autophagy and cancer stemness requires further investigation. In this study, it was found that luminal and triple‐negative breast cancers require distinct therapeutic approaches because of their different amounts of autophagy flux. We identified that autophagy flux was inhibited in triple‐negative breast cancer (TNBC) CSCs. Moreover, miRNA‐181a (miR‐181a) expression is upregulated in both TNBC CSCs and patient tissues. Autophagy‐related 5 (ATG5) and autophagy‐related 2B (ATG2B) participate in the early formation of autophagosomes and were revealed as targets of miR‐181a. Inhibition of miR‐181a expression led to attenuation of TNBC stemness and an increase in autophagy flux. Furthermore, treatment with curcumin led to attenuation of cancer stemness in TNBC CSCs; the expression of ATG5 and ATG2B was enhanced and there was an increase of autophagy flux. These results indicated that ATG5 and ATG2B are involved in the suppression of cancer stemness in TNBC. In summary, autophagy inhibits cancer stemness through the miR‐181a‐regulated mechanism in TNBC. Promoting tumor‐suppressive autophagy using curcumin may be a potential method for the treatment of TNBC.

Crocin exerts anti-proliferative and apoptotic effects on cutaneous squamous cell carcinoma via miR-320a/ATG2B

Cutaneous squamous cell carcinoma (cSCC) is a highly prevalent skin malignancy, and the effective therapy still remains a challenge. Crocin can be used for cSCC therapy. This study explored the effects of cSCC cells treatment with crocin in vitro and in vivo. The study used A431 and SCL-1 cells lines, cSCC human samples and BALB/C nude mice for investigations. Apoptosis was determined by MTT assays, while miR-320a and ATG2B expressions were validated through RT-qPCR. Interaction of miR-320a with ATG2B was examined via dual luciferase reporter assay. The autophagy and apoptosis proteins expressions were further confirmed through western blot and immunofluorescence staining assays. The results indicated a significantly upregulated miR-320a, but a down-regulated ATG2B expression in the cSCC clinical samples. Crocin significantly repressed cSCC cells growth, and induced apoptosis through autophagy. Furthermore, miR-320a expression was inhibited and ATG2B expression was increased. Dual luciferase reporter assay revealed that miR-320a regulated ATG2B expression directly. Additionally, the upregulation of ATG2B expression in cSCC cells inhibited cell proliferation and led to cell apoptosis. Crocin also reduced tumor growth and stimulated the apoptosis in vivo. In conclusion, miR-320a is upregulated and ATG2B is down-regulated in cSCC, Crocin suppresses the proliferation and induces apoptosis of cSCC cells. Further, Crocin increases autophagy while miR-320a hinders autophagy and the apoptotic effects of crocin on cSCC cells. MiR-320a binds ATG2B directly, and ATG2B expression is upregulated by crocin. Finally, Crocin triggers cSCC cells apoptosis in vivo. Crocin can target ATG2B/miR-320a and may be an effective alternative for cSCC treatment.

Optimization of BCG Therapy Targeting Neutrophil Extracellular Traps, Autophagy, and miRNAs in Bladder Cancer: Implications for Personalized Medicine

Bladder cancer (BC) is the ninth most common cancer and the thirteenth most common cause of mortality worldwide. Bacillus Calmette Guerin (BCG) instillation is a common treatment option for BC. BCG therapy is associated with the less adversary effects, compared to chemotherapy, radiotherapy, and other conventional treatments. BCG could inhibit the progression and recurrence of BC by triggering apoptosis pathways, arrest cell cycle, autophagy, and neutrophil extracellular traps (NETs) formation. However, BCG therapy is not efficient for metastatic cancer. NETs and autophagy were induced by BCG and help to suppress the growth of tumor cells especially in the primary stages of BC. Activated neutrophils can stimulate autophagy pathway and release NETs in the presence of microbial pathogenesis, inflammatory agents, and tumor cells. Autophagy can also regulate NETs formation and induce production of reactive oxygen species (ROS) and NETs. Moreover, miRNAs are important regulator of gene expression. These small non-coding RNAs are also considered as an essential factor to control the levels of tumor development. However, the interaction between BCG and miRNAs has not been well-understood yet. Therefore, the present study discusses the roles of miRNAs in regulations of autophagy and NETs formation in BCG therapy in the treatment of BC. The roles of autophagy and NETs formation in BC treatment and efficiency of BCG are also discussed.

Perturbation-Based Modeling Unveils the Autophagic Modulation of Chemosensitivity and Immunogenicity in Breast Cancer Cells

In the absence of new therapeutic strategies, chemotherapeutic drugs are the most widely used strategy against metastatic breast cancer, in spite of eliciting multiple adverse effects and having low responses with an average 5-year patient survival rate. Among the new therapeutic targets that are currently in clinical trials, here, we addressed the association between the regulation of the metabolic process of autophagy and the exposure of damage-associated molecular patterns associated (DAMPs) to immunogenic cell death (ICD), which has not been previously studied. After validating an mCHR-GFP tandem LC3 sensor capacity to report dynamic changes of the autophagic metabolic flux in response to external stimuli and demonstrating that both basal autophagy levels and response to diverse autophagy regulators fluctuate among different cell lines, we explored the interaction between autophagy modulators and chemotherapeutic agents in regards of cytotoxicity and ICD using three different breast cancer cell lines. Since these interactions are very complex and variable throughout different cell lines, we designed a perturbation-based model in which we propose specific modes of action of chemotherapeutic agents on the autophagic flux and the corresponding strategies of modulation to enhance the response to chemotherapy. Our results point towards a promising therapeutic potential of the metabolic regulation of autophagy to overcome chemotherapy resistance by eliciting ICD.

Serum Exosomal Dicer Is a Useful Biomarker for Early Detection of Differentiated Gastric Adenocarcinoma

BACKGROUND AND AIM

A recent basic study identified that Dicer is contained in exosomes derived from cancer cells and plays crucial roles in microRNA maturation and cancer development. Based on this novel basic concept, we analyzed the usefulness of serum exosomal Dicer as a diagnostic biomarker for gastrointestinal cancers.

METHODS

Enrolled participants (691) were categorized into 3 groups: gastric cancer (GC) cohort, 183 patients (90 healthy controls (HCs) and 93 GC patients); esophageal cancer (EC) cohort, 115 patients (90 HCs and 25 EC patients); and colorectal cancer (CRC) cohort, 188 patients (92 HCs and 96 CRC patients) after age- and sex matching using the propensity score. The quality of isolated serum exosomes was validated with an electron microscope, particle size analyzer, and exosome marker, CD63.

RESULTS

Serum exosomal Dicer was significantly higher in the GC group than in the HC group (p = 0.004), whereas no significant differences were found in both EC and CRC cohorts. Serum exosomal Dicer was significantly higher in only differentiated gastric adenocarcinoma and not in the undifferentiated type. Moreover, serum exosomal Dicer showed no significant differences regardless of Helicobacter pylori (H. pylori) status. The biomarker panel combining serum exosomal Dicer with H. pylori status distinguished between HC and differentiated GC patients with an area under the curve (AUC) of 0.762. As for early-stage diagnosis, this combination distinguished between HC and stage I differentiated GC with an AUC = 0.758.

CONCLUSIONS

Serum exosomal Dicer is a potential noninvasive diagnostic biomarker for early detection of differentiated gastric adenocarcinoma.

Identification of autophagy-associated miRNA signature for the cervical squamous cell cancer and high-grade cervical intraepithelial lesions

Cervical cancer markedly threatens women's health worldwide and currently ranks fourth leading cause of cancer mortality in women according to recent global cancer statistics. Recent advances have proven that not only tumor suppressor and oncogenes but also non-coding RNAs including micro RNAs (miRNAs) have significant impact in the development and progression of cervical cancers. Previous studies have identified many cancer-specific miRNAs for the early detection of cervical cancers. However, the diagnostic and prognostic use of autophagy-associated miRNAs for the cervical squamous cell cancer (SCC) cases and high-grade squamous intraepithelial lesion (HSIL) have not been uncovered. In the present study, we revealed that miRNAs are differentially expressed in both cervical SCC and HSIL. A total of 35 HSIL, 35 cervical SCC and 30 healthy controls were enrolled for the present study. Total RNA including miRNAs were isolated from the FFPE tissue samples and miRNA expression levels were quantified by quantitative PCR. Predicted miRNA targets of autophagy related genes were determined using miRNA-target prediction algorithms. MiR-143, miR-372, miR-375 and miR-30c were markedly downregulated in HSIL and cervical SCC. MiR-130a was significantly upregulated in the cervical SCC group compared to HSIL and control groups. MiR-30a, miR-520e, miR-548c and miR-372 were significantly associated with the overall survival of cervical SCC patients and these miRNAs were determined to be significant diagnostic markers as revealed by ROC analysis. Together, these results indicate that autophagy-associated miRNAs are potentially valuable for the differential diagnosis and targeted therapy to cervical cancer.

Epigenetic regulation of autophagy: A key modification in cancer cells and cancer stem cells

Aberrant epigenetic alterations play a decisive role in cancer initiation and propagation via the regulation of key tumor suppressor genes and oncogenes or by modulation of essential signaling pathways. Autophagy is a highly regulated mechanism required for the recycling and degradation of surplus and damaged cytoplasmic constituents in a lysosome dependent manner. In cancer, autophagy has a divergent role. For instance, autophagy elicits tumor promoting functions by facilitating metabolic adaption and plasticity in cancer stem cells (CSCs) and cancer cells. Moreover, autophagy exerts pro-survival mechanisms to these cancerous cells by influencing survival, dormancy, immunosurveillance, invasion, metastasis, and resistance to anti-cancer therapies. In addition, recent studies have demonstrated that various tumor suppressor genes and oncogenes involved in autophagy, are tightly regulated via different epigenetic modifications, such as DNA methylation, histone modifications and non-coding RNAs. The impact of epigenetic regulation of autophagy in cancer cells and CSCs is not well-understood. Therefore, uncovering the complex mechanism of epigenetic regulation of autophagy provides an opportunity to improve and discover novel cancer therapeutics. Subsequently, this would aid in improving clinical outcome for cancer patients. In this review, we provide a comprehensive overview of the existing knowledge available on epigenetic regulation of autophagy and its importance in the maintenance and homeostasis of CSCs and cancer cells.

Role of Long Non-Coding RNA Polymorphisms in Cancer Chemotherapeutic Response

Genetic polymorphisms are defined as the presence of two or more different alleles in the same locus, with a frequency higher than 1% in the population. Since the discovery of long non-coding RNAs (lncRNAs), which refer to a non-coding RNA with a length of more than 200 nucleotides, their biological roles have been increasingly revealed in recent years. They regulate many cellular processes, from pluripotency to cancer. Interestingly, abnormal expression or dysfunction of lncRNAs is closely related to the occurrence of human diseases, including cancer and degenerative neurological diseases. Particularly, their polymorphisms have been found to be associated with altered drug response and/or drug toxicity in cancer treatment. However, molecular mechanisms are not yet fully elucidated, which are expected to be discovered by detailed studies of RNA–protein, RNA–DNA, and RNA–lipid interactions. In conclusion, lncRNAs polymorphisms may become biomarkers for predicting the response to chemotherapy in cancer patients. Here we review and discuss how gene polymorphisms of lncRNAs affect cancer chemotherapeutic response. This knowledge may pave the way to personalized oncology treatments.

MicroRNA-146a inhibits autophagy to maintain the intracellular survival of Burkholderia pseudomallei by targeting LIPA

Burkholderia pseudomallei is the etiological agent of melioidosis, which is an emerging infectious disease endemic to many tropical regions. Autophagy is an intrinsic cellular process that degrades cytoplasmic components and plays an important role in protecting the host against pathogens. Like many intracellular pathogens, B. pseudomallei can evade the autophagy-dependent cellular clearance. However, the underlying mechanism remains unclear. In this study, we applied a combination of multiple assays to monitor autophagy processes and found that B. pseudomallei induced an incomplete autophagic flux and eliminate autophagy clearance in macrophages by blocking autophagosome-lysosome fusion. Based on a high-throughput microarray screening, we found that LIPA (lysosomal acid LIPAse A) was downregulated during B. pseudomallei infection. MiR-146a was then identified to be specifically upregulated upon infection with B. pseudomallei and further regulated LIPA expression by interacting with 3'UTR of LIPA. Furthermore, overexpression of miR-146a contributed to the defect of autophagic flux caused by B. pseudomallei and was beneficial for the survival of B. pseudomallei in macrophages. Therefore, our findings suggest that miR-146a inhibits autophagy via posttranscriptional suppression of LIPA expression to maintain B. pseudomallei survival in macrophages.

Cephalotaxine Inhibits the Survival of Leukemia Cells by Activating Mitochondrial Apoptosis Pathway and Inhibiting Autophagy Flow

Cephalotaxine (CET) is a natural alkaloid with potent antileukemia effects. However, its underlying molecular mechanism has not been well understood. In this study, we verified that CET significantly inhibited the viability of various leukemia cells, including HL-60, NB4, Jurkat, K562, Raji and MOLT-4. RNA-sequencing and bioinformatics analysis revealed that CET causes mitochondrial function change. Mechanism research indicated that CET activated the mitochondrial apoptosis pathway by reducing the mitochondrial membrane potential, downregulating anti-apoptotic Bcl-2 protein and upregulating pro-apoptotic Bak protein. In addition, the autophagy signaling pathway was highly enriched by RNA-seq analysis. Then, we found that CET blocked the fluorescence colocation of MitoTracker Green and LysoTracker Red and upregulated the level of LC3-II and p62, which indicated that autophagy flow was impaired. Further results demonstrated that CET could impair lysosomal acidification and block autophagy flow. Finally, inhibiting autophagy flow could aggravate apoptosis of HL-60 cells induced by CET. In summary, this study demonstrated that CET exerted antileukemia effects through activation of the mitochondria-dependent pathway and by impairing autophagy flow. Our research provides new insights into the molecular mechanisms of CET in the treatment of leukemia.

MiR-15a-5p Confers Chemoresistance in Acute Myeloid Leukemia by Inhibiting Autophagy Induced by Daunorubicin

Anthracyclines remain a cornerstone of induction chemotherapy for acute myeloid leukemia (AML). Refractory or relapsed disease due to chemotherapy resistance is a major obstacle in AML management. MicroRNAs (miRNAs) have been observed to be involved in chemoresistance. We previously observed that miR-15a-5p was overexpressed in a subgroup of chemoresistant cytogenetically normal AML patients compared with chemosensitive patients treated with daunorubicin and cytarabine. MiR-15a-5p overexpression in AML cells reduced apoptosis induced by both drugs in vitro. This study aimed to elucidate the mechanisms by which miR-15a-5p contributes to daunorubicin resistance. We showed that daunorubicin induced autophagy in myeloid cell lines. The inhibition of autophagy reduced cell sensitivity to daunorubicin. The overexpression of miR-15a-5p decreased daunorubicin-induced autophagy. Conversely, the downregulation of miR-15a-5p increased daunorubicin-induced autophagy. We found that miR-15a-5p targeted four genes involved in autophagy, namely ATG9a, ATG14, GABARAPL1 and SMPD1. Daunorubicin increased the expression of these four genes, and miR-15a-5p counteracted this regulation. Inhibition experiments with the four target genes showed the functional effect of miR-15a-5p on autophagy. In summary, our results indicated that miR-15a-5p induces chemoresistance in AML cells through the abrogation of daunorubicin-induced autophagy, suggesting that miR-15a-5p could be a promising therapeutic target for chemoresistant AML patients.

Voluntary wheel-running exercise attenuates brain aging of rats through activating miR-130a-mediated autophagy

Autophagy is a highly regulated intracellular process for the degradation of protein aggregates and damaged organelles. Recently, autophagy has been implicated in Alzheimer's disease (AD) and aging. Autophagy process is regulated by the recruitment and assembly of several autophagy-related genes (Atgs) such as, Atg7 and LC3, as the highly conserved and important markers involved in the regulation of autophagy. We recently reported the reduced LC3-II/LC3-I ratio, down-regulated ATG7, and increased p62 protein levels in hippocampal tissues of aging rats. MicroRNA-130a (miR-130a) plays a crucial role in physiological and pathological processes, but whether miR-130a affects the autophagy of brain is unknown. We aim to explore the regulatory role of miR-130a on the autophagy and cell senescence of SH-SY5Y, as well as LC3-II/LC3-I ratio, and the expression of p62, ATG7, Ac-p53 and p21 during exercise intervention of aging rats. In this study, miR-130a expression was markedly down-regulated in the hippocampal of aged rats companying with up-regulated expression of Ac-p53 and p21 when compared with young rats. In contrast, voluntary wheel running could up-regulate miR-130a expression; decrease the expression of Ac-p53 and p21 in aging rats. Interestingly, exercise reversed the impaired autophagy resulted from aging possibly by activating AMPK signaling. Moreover, overexpression of miR-130a in d-galactose (D-gal)-induced SH-SY5Y cell senescence model attenuated d-gal-induced impaired autophagy and cell senescence, demonstrated by decreased levels of LC3, Ac-p53, p21 and increased p62, suggesting that voluntary wheel running can alleviate brain aging in natural aging rats by up-regulating miR-130a-mediated autophagy.

The interplay of microRNAs and transcription factors in autophagy regulation in nonalcoholic fatty liver disease

The autophagy-lysosomal degradation system has an important role in maintaining liver homeostasis by removing unnecessary intracellular components. Impaired autophagy has been linked to nonalcoholic fatty liver disease (NAFLD), which includes hepatitis, steatosis, fibrosis, and cirrhosis. Thus, gaining an understanding of the mechanisms that regulate autophagy and how autophagy contributes to the development and progression of NAFLD has become the focus of recent studies. Autophagy regulation has been thought to be primarily regulated by cytoplasmic processes; however, recent studies have shown that microRNAs (miRNAs) and transcription factors (TFs) also act as key regulators of autophagy by targeting autophagy-related genes. In this review, we summarize the miRNAs and TFs that regulate the autophagy pathway in NAFLD. We further focus on the transcriptional and posttranscriptional regulation of autophagy and discuss the complex regulatory networks involving these regulators in autophagy. Finally, we highlight the potential of targeting miRNAs and TFs involved in the regulation of autophagy for the treatment of NAFLD.

LncRNA-HOTAIR activates autophagy and promotes the imatinib resistance of gastrointestinal stromal tumor cells through a mechanism involving the miR-130a/ATG2B pathway

Gastrointestinal stromal tumors (GISTs) are common neoplasms of the gastrointestinal tract that can be treated successfully using C-kit target therapy and surgery; however, imatinib chemoresistance is a major barrier to success in therapy. The present study aimed to discover alternative pathways in imatinib-resistant GISTs. Long noncoding RNAs (lncRNAs) are newly discovered regulators of chemoresistance. Previously, we showed that the lncRNA HOTAIR was upregulated in recurrent GISTs. In this study, we analyzed differentially expressed lncRNAs after imatinib treatment and found that HOTAIR displayed the largest increase. The distribution of HOTAIR in GISTs was shifted from nucleus to cytoplasm after imatinib treatments. The expression of HOTAIR was validated as related to drug sensitivity through Cell Counting Kit-8 assays. Moreover, HOTAIR was associated strongly with cell autophagy and regulated drug sensitivity via autophagy. Mechanistically, HOTAIR correlated negatively with miRNA-130a in GISTs. The downregulation of miRNA-130a reversed HOTAIR-small interfering RNA-induced suppression of autophagy and imatinib sensitivity. We identified autophagy-related protein 2 homolog B (ATG2B) as a downstream target of miR-130a and HOTAIR. ATG2B downregulation reversed the effect of pEX-3-HOTAIR/miR-130a inhibitor on imatinib sensitivity. Finally, HOTAIR was shown to influence the autophagy and imatinib sensitivity of GIST cells in mouse tumor models. Our results suggested that HOTAIR targets the ATG2B inhibitor miR-130a to upregulate the level of cell autophagy so that promotes the imatinib resistance in GISTs.

Oncogenic role of MIR516A in human bladder cancer was mediated by its attenuating PHLPP2 expression and BECN1-dependent autophagy

Although MIR516A has been reported to be downregulated and act as a tumor suppressor in multiple cancers, its expression and potential contribution to human bladder cancer (BC) remain unexplored. Unexpectedly, we showed here that MIR516A was markedly upregulated in human BC tissues and cell lines, while inhibition of MIR516A expression attenuated BC cell monolayer growth in vitro and xenograft tumor growth in vivo, accompanied with increased expression of PHLPP2. Further studies showed that MIR516A was able to directly bind to the 3'-untranslated region of PHLPP2 mRNA, which was essential for its attenuating PHLPP2 expression. The knockdown of PHLPP2 expression in MIR516A-inhibited cells could reverse BC cell growth, suggesting that PHLPP2 is a MIR516A downstream mediator responsible for MIR516A oncogenic effect. PHLPP2 was able to mediate BECN1/Beclin1 stabilization indirectly, therefore promoting BECN1-dependent macroautophagy/autophagy, and inhibiting BC tumor cell growth. In addition, our results indicated that the increased autophagy by attenuating MIR516A resulted in a dramatic inhibition of xenograft tumor formation in vivo. Collectively, our results reveal that MIR516A has a novel oncogenic function in BC growth by directing binding to PHLPP2 3'-UTR and inhibiting PHLPP2 expression, in turn at least partly promoting CUL4A-mediated BECN1 protein degradation, thereby attenuating autophagy and promoting BC growth, which is a distinct function of MIR516A identified in other cancers.Abbreviation: ATG3: autophagy related 3; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; BAF: bafilomycin A1; BC: bladder cancer; CHX: cycloheximide; Co-IP: co-immunoprecipitation; CUL3: cullin 3; CUL4A: cullin 4A; CUL4B: cullin 4B; IF: immunofluorescence: IHC-p: immunohistochemistry-paraffin; MIR516A: microRNA 516a (microRNA 516a1 and microRNA 516a2); MS: mass spectrometry; PHLPP2: PH domain and leucine rich repeat protein phosphatase.

MicroRNA-130a inhibits proliferation of vascular smooth muscle cells by suppressing autophagy via ATG2B

Numerous microRNAs participate in regulating the pathological process of atherosclerosis. We have found miR-130a is one of the most significantly down-regulated microRNAs in arteriosclerosis obliterans. Our research explored the function of miR-130a in regulating proliferation by controlling autophagy in arteriosclerosis obliterans development. A Gene Ontology (GO) enrichment analysis of miR-130a target genes indicated a correlation between miR-130a and cell proliferation. Thus, cell cycle, CCK-8 assays and Western blot analysis were performed, and the results indicated that miR-130a overexpression in vascular smooth muscle cells (VSMCs) significantly attenuated cell proliferation, which was validated by an in vivo assay in a rat model. Moreover, autophagy is thought to be involved in the regulation of proliferation. As our results indicated, miR-130a could inhibit autophagy, and ATG2B was predicted to be a target of miR-130a. The autophagy inhibition effect of miR-130a overexpression was consistent with the effect of ATG2B knockdown. The results that ATG2B plasmids and miR-130a mimics were cotransfected in VSMCs further confirmed our conclusion. In addition, by using immunohistochemistry, the positive results of LC3 II/I and ATG2B in the rat model and artery vascular tissues from the patient were in accordance with in vitro data. In conclusion, our data demonstrate that miR-130a inhibits VSMCs proliferation via ATG2B, which indicates that miR-130a could be a potential therapeutic target that regulates autophagy in atherosclerosis obliterans.

MicroRNAs: Tiny Regulators of Gene Expression with Pivotal Roles in Normal B-Cell Development and B-Cell Chronic Lymphocytic Leukemia

Simple Summary

The involvement of miRNAs in physiological cellular processes has been well documented. The development of B cells, which is dictated by a miRNA-transcription factor regulatory network, suggests a typical process partly orchestrated by miRNAs. Besides their contribution in normal hematopoiesis, miRNAs have been severally reported to be implicated in hematological malignancies, a typical example of which is B-cell chronic lymphocytic leukemia (B-CLL). Numerous studies have attempted to highlight the regulatory role of miRNAs in B-CLL or establish some of them as molecular biomarkers or therapeutic targets. Thus, a critical review summarizing the current knowledge concerning the multifaceted role of miRNAs in normal B-cell development and B-CLL progression, prognosis, and therapy, is urgent. Moreover, this review aims to highlight important miRNAs in both normal B-cell development and B-CLL and discuss future perspectives concerning their regulatory potential and establishment in clinical practice.

Abstract

MicroRNAs (miRNAs) represent a class of small non-coding RNAs bearing regulatory potency. The implication of miRNAs in physiological cellular processes has been well documented so far. A typical process orchestrated by miRNAs is the normal B-cell development. A stage-specific expression pattern of miRNAs has been reported in the developmental procedure, as well as interactions with transcription factors that dictate B-cell development. Besides their involvement in normal hematopoiesis, miRNAs are severally implicated in hematological malignancies, a typical paradigm of which is B-cell chronic lymphocytic leukemia (B-CLL). B-CLL is a highly heterogeneous disease characterized by the accumulation of abnormal B cells in blood, bone marrow, lymph nodes, and spleen. Therefore, timely, specific, and sensitive assessment of the malignancy is vital. Several studies have attempted to highlight the remarkable significance of miRNAs as regulators of gene expression, biomarkers for diagnosis, prognosis, progression, and therapy response prediction, as well as molecules with potential therapeutic utility. This review seeks to outline the linkage between miRNA function in normal and malignant hematopoiesis by demonstrating the main benchmarks of the implication of miRNAs in the regulation of normal B-cell development, and to summarize the key findings about their value as regulators, biomarkers, or therapeutic targets in B-CLL.

CAFs-Derived Exosomal miRNA-130a Confers Cisplatin Resistance of NSCLC Cells Through PUM2-Dependent Packaging

PURPOSE

Chemoresistance is a significant barrier to the treatment and management of non-small cell lung cancer (NSCLC). Exosomes play an essential role in intercellular communication. Understanding the mechanism underlying the role of tumor stroma, especially cancer-associated fibroblasts (CAFs), during chemoresistance would significantly contribute to the clinical application of chemotherapy agents.

RESULTS

In this study, we demonstrated that NSCLC-derived CAFs were innately resistant to cisplatin treatment and CAFs-conditioned medium significantly promoted the survival rate of NSCLC cells after cisplatin treatment. Additionally, CAFs-derived exosomes were taken up by NSCLC cells. Moreover, exosomal miRNA-130a was transferred from CAFs to recipient NSCLC cells and knockdown of miRNA-130a reversed the effect of CAFs-derived exosomes during chemoresistance of NSCLC cells. Furthermore, pumilio homolog 2 (PUM2), a RNA-binding protein, mediated the packaging of miRNA-130a into exosomes. The overexpression and knockdown of PUM2 promoted and inhibited tumor growth of xenograft mice, respectively.

CONCLUSION

Taken together, these results suggest that CAFs-derived exosomes confer cisplatin resistance of NSCLC cells through transferring miRNA-130a and that PUM2 is a critical factor for packaging miRNA-130a into exosomes. This study indicates that CAFs-derived exosomal miRNA-130a may be a potential therapeutic target for cisplatin resistance in NSCLC.

Enhanced Expression of miR-181b in B Cells of CLL Improves the Anti-Tumor Cytotoxic T Cell Response

The clinical progression of B cell chronic lymphocytic leukemia (CLL) is associated with immune cell dysfunction and a strong decrease of miR-181b-5p (miR-181b), promoting the death of CLL cells. Here we investigated whether the reduction of miR-181b impairs the immune response in CLL. We demonstrate that activated CD4+ T cells increase miR-181b expression in CLL through CD40-CD40L signaling, which enhances the maturation and activity of cytotoxic T cells and, consequently, the apoptotic response of CLL cells. The cytotoxic response is facilitated by a depletion of the anti-inflammatory cytokine interleukin 10, targeted by miR-181b. In vivo experiments in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice confirmed that miR-181b promotes the apoptotic death of CLL cells only when functional T cells are restored. Overall, our findings suggest that the reinstatement of miR-181b in CLL cells could be an exploitable adjuvant therapeutic option for the treatment of CLL.

Identification of a miRNA based model to detect prognostic subgroups in patients with aggressive B-cell lymphoma

In order to differentiate prognostic subgroups of patients with aggressive B-cell lymphoma, we analyzed the expression of 800 miRNAs with the NanoString nCounter human miRNA assay on a cohort of 228 FFPE samples of patients enrolled in the RICOVER-60 and MegaCHOEP trials. We identified significant miRNA signatures for overall survival (OS) and progression-free survival (PFS) by LASSO-penalized linear Cox-regression. High expression levels of miR-130a-3p and miR-423-5p indicate a better prognosis, whereas high levels of miR-374b-5p, miR-590-5p, miR-186-5p, and miR-106b-5p increase patients' risk levels for OS. Regarding PFS high expression of miR-365a-5p in addition to the other two miRNAs improves the prognosis and high levels of miR374a-5p, miR-106b-5p, and miR-590-5p, connects with increased risk and poor prognosis. We identified miRNA signatures to subdivide patients into two different risk groups. These prognostic models may be used in risk stratification in future clinical trials and help making personalized therapy decisions.

Epigenetic silencing of miR-342-3p in B cell lymphoma and its impact on autophagy

Background

miR-342-3p, localized to 14q32, is a tumor suppressor miRNA implicated in carcinogenesis. Given the presence of a promotor-associated CpG island for its host gene, EVL, we hypothesized that intronic miR-342-3p is a tumor suppressor co-regulated with host gene by promoter DNA methylation in B cell lymphoma.

Results

By bisulfite pyrosequencing-verified methylation-specific PCR (MSP), EVL/MIR342 methylation was detected in five (50%) lymphoma cell lines but not normal peripheral blood and tonsils. EVL/MIR342 methylation correlated with repression of both miR-342-3p and EVL in cell lines. In completely methylated SU-DHL-16 cells, 5-AzadC treatment resulted in promoter demethylation and re-expression of miR-342-3p and EVL. In 132 primary lymphoma samples, EVL/MIR342 was preferentially methylated in B cell lymphomas (N = 68; 68.7%) than T cell lymphoma (N = 8; 24.2%) by MSP (P < 0.0001). Moreover, EVL/MIR342 methylation was associated with lower miR-342-3p expression in 79 primary NHL (P = 0.0443). In SU-DHL-16 cells, the tumor suppressor function of miR-342-3p was demonstrated by the inhibition of cellular proliferation and increase of cell death upon over-expression of miR-342-3p. Mechanistically, overexpression of miR-342-3p resulted in a decrease of LC3-II, a biomarker of autophagy, which was pro-survival for SU-DHL-16. Pre-treatment with 3-methyladenine, an autophagy inhibitor, abrogated tumor suppression associated with miR-342-3p overexpression. By luciferase assay, MAP1LC3B, a precursor of LC3-II, was confirmed as a direct target of miR-342-3p. Finally, in SU-DHL-16 cells, overexpression of miR-342-3p downregulated the known target DNMT1, with promoter demethylation and re-expression of tumor suppressor E-cadherin.

Conclusions

Intronic miR-342-3p is co-regulated with its host gene EVL by tumor-specific promoter DNA methylation in B cell lymphoma. The tumor suppressor function of miR-342-3p was mediated via inhibition of pro-survival autophagy by targeting MAP1LC3B and downregulation of DNMT1 with demethylation and re-expression of tumor suppressor genes.

The effect of miRNA and autophagy on colorectal cancer

Colorectal cancer (CRC) has become a concern because of its high recurrence rate and metastasis rate, low early diagnosis rate and poor therapeutic effect. At present, various studies have shown that autophagy is closely connected with the occurrence and progression of CRC. Autophagy is a highly cytosolic catabolic process involved in lysosomes in biological evolution. Cells degrade proteins and damaged organelles by autophagy to achieve material circulation and maintain cell homeostasis. Moreover, microRNAs are key regulators of autophagy, and their mediated regulation of transcriptional and post-transcriptional levels plays an important role in autophagy in CRC cells. This review focuses on the recent research advances of how autophagy and related microRNAs are involved in affecting occurrence and progression of CRC and provides a new perspective for the study of CRC treatment strategies.

Dicing the Disease with Dicer: The Implications of Dicer Ribonuclease in Human Pathologies

Gene expression dictates fundamental cellular processes and its de-regulation leads to pathological conditions. A key contributor to the fine-tuning of gene expression is Dicer, an RNA-binding protein (RBPs) that forms complexes and affects transcription by acting at the post-transcriptional level via the targeting of mRNAs by Dicer-produced small non-coding RNAs. This review aims to present the contribution of Dicer protein in a wide spectrum of human pathological conditions, including cancer, neurological, autoimmune, reproductive and cardiovascular diseases, as well as viral infections. Germline mutations of Dicer have been linked to Dicer1 syndrome, a rare genetic disorder that predisposes to the development of both benign and malignant tumors, but the exact correlation of Dicer protein expression within the different cancer types is unclear, and there are contradictions in the data. Downregulation of Dicer is related to Geographic atrophy (GA), a severe eye-disease that is a leading cause of blindness in industrialized countries, as well as to psychiatric and neurological diseases such as depression and Parkinson's disease, respectively. Both loss and upregulation of Dicer protein expression is implicated in severe autoimmune disorders, including psoriasis, ankylosing spondylitis, rheumatoid arthritis, multiple sclerosis and autoimmune thyroid diseases. Loss of Dicer contributes to cardiovascular diseases and causes defective germ cell differentiation and reproductive system abnormalities in both sexes. Dicer can also act as a strong antiviral with a crucial role in RNA-based antiviral immunity. In conclusion, Dicer is an essential enzyme for the maintenance of physiology due to its pivotal role in several cellular processes, and its loss or aberrant expression contributes to the development of severe human diseases. Further exploitation is required for the development of novel, more effective Dicer-based diagnostic and therapeutic strategies, with the goal of new clinical benefits and better quality of life for patients.

Chidamide, a histone deacetylase inhibitor, inhibits autophagy and exhibits therapeutic implication in chronic lymphocytic leukemia

Novel agents have made the management of chronic lymphocytic leukemia (CLL) more promising and personalized. However, long-term treatment is still warranted which may result in toxicity and resistance. Thus, new combination therapy may help achieve deeper remission and limited-duration therapy. Histone deacetylase inhibitors (HDACi) can affect many tumors by modulating key biological functions including autophagy. Studies have shown that some novel targeted agents including ibrutinib induce autophagy. This study aimed to explore the effect of oral HDAC inhibitor, chidamide, on CLL cells as well as the role of autophagy in this process. Here, we showed that autophagy flux in CLL cells was inhibited by chidamide via post-transcriptional modulation and chidamide had cytostatic and cytotoxic effects on CLL cells. Besides, the pro-survival role of autophagy in CLL cells was validated by using autophagy inhibitor and knocking down critical autophagy gene. Notably, a combination of chidamide and ibrutinib showed significant synergism and downregulated ibrutinib-induced autophagy. This work highlights the therapeutic potential of chidamide via its effect on autophagy, especially in combination with ibrutinib.

Overexpression of microRNA-130a predicts adverse prognosis of primary gastrointestinal diffuse large B-cell lymphoma

Primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL) is a highly heterogeneous type of non-Hodgkin lymphoma. A number of studies have demonstrated that microRNA-130a (miR-130a) serves a role in the tumorigenesis and prognosis of numerous human tumors. However, to the best of our knowledge, the prognostic significance of miR-130a in PGI-DLBCL remains unknown. The present study explored the association between miR-130a and the clinical outcomes of PGI-DLBCL. Relative miR-130a expression was assessed by reverse transcription-quantitative PCR. Immunohistochemistry was used to detect expression levels of BCL-2, c-MYC, neprilysin, B-cell lymphoma 6 protein, PWWP domain-containing DNA repair factor 3A and proliferation marker protein Ki-67. A receiver operating characteristic curve was constructed to analyze the specificity and sensitivity of microRNA levels in the diagnosis of PGI-DLBCL. Survival curves were constructed using the Kaplan-Meier method. In the present study, miR-130a expression was notably higher in patients with PGI-DLBCL compared with in the controls (P<0.0001). miR-130a overexpression was closely associated with a high International Prognostic Index score (3–5) and drug resistance (P=0.017 and P=0.044, respectively). No significant difference in other clinical features was observed. Patients with increased expression levels of miR-130a had lower overall survival [hazard ratio (HR), 2.998; 95% CI, 1.347-6.673; P=0.007] and progression-free survival (HR, 3.325; 95% CI, 1.488-7.429; P=0.003) compared with patients who had lower expression levels of miR-130a. Furthermore, multivariate Cox regression analysis suggested that miR-130a was a negative prognostic parameter in PGI-DLBCL. Therefore, upregulation of miR-130a could become a potential prognostic marker for PGI-DLBCL. Additionally, further study of these results may have important guiding significance for the prognosis of patients with PGI-DLBCL in the clinical setting.

MicroRNA-425 inhibits proliferation of chronic lymphocytic leukaemia cells through regulation of the Bruton's tyrosine kinase/phospholipase Cγ2 signalling pathway

The present study aimed to investigate the effects of microRNA (miR)-425 on the proliferation of chronic lymphocytic leukaemia (CLL) cells and the possible underlying mechanisms. The expression of miR-425 was determined in the B lymphocytes of CLL patients and in normal B lymphocytes by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, MEC-1 cells transfected with miR-425 negative control (NC) or miR-425 mimic were examined. The cell proliferation of different groups was evaluated using an MTT assay, and cell cycle distribution was evaluated using flow cytometry analysis. A dual-luciferase reporter assay was used to verify whether Bruton's tyrosine kinase (BTK) was a target of miR-425. Furthermore, the expression levels of BTK, phospholipase Cγ2 (PLCγ2), Ki-67 and proliferating cell nuclear antigen (PCNA) were determined by RT-qPCR and western blotting. The results revealed that the expression of miR-425 was significantly downregulated in B lymphocytes obtained from CLL patients as compared with that in normal B lymphocytes. When cells were transfected with miR-425 mimic, the proliferation of MEC-1 cells was significantly inhibited at 24, 48 and 72 h compared with the proliferation of control cells. Additionally, the ratio of G0/G1 cells was significantly increased and the ratio of G2/M cells was significantly decreased in miR-425-overexpressing cells compared with that in control cells. The luciferase reporter assay revealed that miR-425 binds to the 3'-untranslated region of BTK mRNA. Finally, BTK, PLCγ2, Ki-67 and PCNA expression was significantly inhibited at the mRNA and protein level in cells where miR-425 was upregulated. In conclusion, miR-425 inhibits the proliferation of MEC-1 cells, potentially by inhibiting BTK/PLCγ2 signalling, and Ki-67 and PCNA expression levels. These results provide a deeper insight for understanding the development of CLL and suggest a potential novel target for the treatment of CLL patients.

Autophagy in cancers including brain tumors: role of MicroRNAs

Autophagy has a crucial role in many cancers, including brain tumors. Several types of endogenous molecules (e.g. microRNAs, AKT, PTEN, p53, EGFR, and NF1) can modulate the process of autophagy. Recently miRNAs (small non-coding RNAs) have been found to play a vital role in the regulation of different cellular and molecular processes, such as autophagy. Deregulation of these molecules is associated with the development and progression of different pathological conditions, including brain tumors. It was found that miRNAs are epigenetic regulators, which influence the level of proteins coded by the targeted mRNAs with any modification of the genetic sequences. It has been revealed that various miRNAs (e.g., miR-7-1-3p, miR-340, miR-17, miR-30a, miR-224-3p, and miR-93), as epigenetic regulators, can modulate autophagy pathways within brain tumors. A deeper understanding of the underlying molecular targets of miRNAs, and their function in autophagy pathways could contribute to the development of new treatment methods for patients with brain tumors. In this review, we summarize the various miRNAs, which are involved in regulating autophagy in brain tumors. Moreover, we highlight the role of miRNAs in autophagy-related pathways in different cancers.

miR-1278 sensitizes nasopharyngeal carcinoma cells to cisplatin and suppresses autophagy via targeting ATG2B

Chemoresistance to cisplatin (DDP) has become a dominating obstacle to the successful treatment of nasopharyngeal carcinoma (NPC). Recently, accumulating data support the tenet that microRNAs (miRNAs) function as new crucial regulators of diverse biological processes, including chemoresistance. In this study, the miRNA expression profiles in NPC were first analyzed using miRNA microarray dataset. miR-1278 was identified as the most decreased miRNA in NPC tissues. We then validated that miR-1278 was significantly down-regulated in NPC tissues and cell lines. Moreover, decreased miR-1278 was strongly associated with worse overall survival and poor chemotherapy response. Gain-of-function experiments showed that overexpression of miR-1278 dramatically sensitized NPC cells to DDP and reduced autophagy. Mechanistically, ATG2B was identified as a target gene of miR-1278. More importantly, ATG2B overexpression reversed miR-1278-induced suppression of autophagy and DDP resistance. Taken together, our results suggested that miR-1278 inhibited the DDP resistance of NPC cells and autophagy through targeting ATG2B. miR-1278 might function as a novel therapeutic target in NPC treatment.

MicroRNA-375 exacerbates knee osteoarthritis through repressing chondrocyte autophagy by targeting ATG2B

Objective: This study aimed to explore the underlying mechanism of miR-375 in exacerbating osteoarthritis (OA).

Results: MiR-375 expression were upregulated in OA cartilage tissues, whereas ATG2B expression was decreased. MiR-375 targeted ATG2B 3’ UTR and inhibited its expression in the chondrocytes, and then suppressed autophagy and promoted endoplasmic reticulum stress (ERs). The apoptosis rate of chondrocytes was increased after being transfected with miR-375 mimics. In vivo results further verified that inhibition of miR-375 could relieve OA-related symptoms.

Conclusion: miR-375 can inhibit the expression of ATG2B in chondrocytes, suppress autophagy and promote the ERs. It suggests that miR-375 could be considered to be a key therapy target for OA.

Methods: Differential expression analyses for mRNA and miRNA microarray datasets from ArrayExpress were performed. MiR-375 and ATG2B expressions in cartilage tissues were detected by qRT-PCR. Dual luciferase assay was applied to verify the targeting relationship between ATG2B and miR-375. In vitro, the role of miR-375 on chondrocyte autophagy and ERs was investigated by western blot and immunofluorescence. The apoptotic rate was quantified by flow cytometry. In vivo, OA mice model was established, HE and Safranin O and Fast Green staining, as well as the OARSI and modified Mankin scores, were applied to measure the OA cartilage damage severity.

Autophagy regulation by microRNAs: Novel insights into osteosarcoma therapy

Osteosarcoma (OS) is a kind of primary bone cancer that is considered as the leading cause of children death. Surgery and chemotherapy are considered as common treatment approaches for OS; the rate of survival for patients is almost 60-70%. Besides the used therapeutic approaches, it seems that there is a crucial need to launch new treatments for OS. In this regard, more understanding about cellular and molecular pathways involved in OS can contribute to recovery and develop new therapeutic platforms. Autophagy is a cellular machinery that digests and degrades dysfunctional proteins and organelles, so it can regulate the cell proliferation and survival. Most of the time, OS cells use autophagy to increase their survival and proliferation and to gain the ability to resist chemotherapy. Although, there are several controversial evidences on how OS cells use autophagy. A variety of cellular and molecular pathways, that is, microRNAs (miRNAs) can modulate autophagy. MiRNAs are some endogenous, approximately 22 nucleotide RNAs that have an important role in posttranscriptional regulation of mRNAs by targeting them. There are many evidences that the various miRNA expressions in OS cells are dysregulated, so it can propel a normal cell to cancerous one by influencing the cell survival, apoptosis, and autophagy, and eventually increased chemoresitance. Hence, miRNAs can be considered as new biomarkers for OS diagnosis, and according to the role of autophagy in OS progression, miRNAs can use inhibiting or promoting autophagy agents. The present review summarizes the effects of aberrant expression of miRNAs in OS diagnosis and treatment with focus on their roles in autophagy.

MicroRNAs as major regulators of the autophagy pathway

Autophagy is a cellular stress response mechanism activation of which leads to degradation of cellular components, including proteins as well as damaged organelles in lysosomes. Defects in autophagy mechanisms were associated with several pathologies (e.g. cancer, neurodegenerative diseases, and rare genetic diseases). Therefore, autophagy regulation is under strict control. Transcriptional and post-translational mechanisms that control autophagy in cells and organisms studied in detail. Recent studies introduced non-coding small RNAs, and especially microRNAs (miRNAs) in the post-translational orchestration of the autophagic activity. In this review article, we analyzed in detail the current status of autophagy-miRNA connections. Comprehensive documentation of miRNAs that were directly involved in autophagy regulation resulted in the emergence of common themes and concepts governing these complex and intricate interactions. Hence, a better and systematic understanding of these interactions reveals a central role for miRNAs in the regulation of autophagy.

Function of Dicer with regard to Energy Homeostasis Regulation, Structural Modification, and Cellular Distribution

As a type III ribonuclease (RNase III) specifically cleaving double-stranded RNA substrates into short fragments, Dicer is indispensable in a range of physi/pathologic processes, e.g., nutrient deprivation, hypoxia, or DNA damage. Therefore, much interest has been paid to the research of this protein as well as its products like microRNAs (miRNAs). The close relationship between Dicer levels and fluctuations of nutrient availability suggests that the protein participates in the regulation of systemic energy homeostasis. Through miRNAs, Dicer regulates the hypothalamic melanocortin-4 system and central autophagy promoting energy expenditure. Moreover, by influencing canonical energy sensors like adenosine monophosphate-activated protein kinase (AMPK) or mammalian target of rapamycin (mTOR), Dicer favors catabolism in the periphery. Taken together, Dicer might be targeted in the control of energy dysregulation. However, factors affecting its RNase activity should be noted. Firstly, modulation of structural integrity affects its role as a ribonuclease. Secondly, although previously known as a cytosolic endoribonuclease, evidence suggests Dicer can relocalize into the nucleus where it could also produce small RNAs. In this review, we probe into involvement of Dicer in energy homeostasis as well as its structural integrity or cellular distribution which affects its ability to produce miRNAs, in the hope of providing novel insights into its mechanism of action for future application.

Programmed death-ligand 1 monoclonal antibody-linked immunoliposomes for synergistic efficacy of miR-130a and oxaliplatin in gastric cancers

Aim: PD-L1 monoclonal antibody-conjugated miR-130a/oxaliplatin-loaded immunoliposomes were constructed for enhanced therapeutic efficacy against gastric cancer. Materials & methods: The in vitro antitumor efficacy of the immunoliposomes was evaluated by cell viability, cell invasion, cell apoptosis and western blot analysis and in vivo antitumor efficacy was evaluated in a HGC27-bearing tumor xenograft model. Results: The inhibitory role of miR-130a was demonstrated in HGC27 cells by the downregulation of RAB5A and FOCL1 signaling pathways. Consequently, PD-miOXNP exhibited the strongest anticancer activity in vitro compared with any other formulation. PD-miOXNP showed a significantly higher anticancer efficacy in HGC27 tumors with reduced Ki67+ cells and increased TUNEL+ cells for mice group. Conclusion: PD-L1 monoclonal antibody-conjugated immunoliposomes have immense potential to be applied as a next-generation nanomedicine for PD-L1-positive gastric cancers.

Autophagy regulation and its role in normal and malignant hematopoiesis

Autophagy, the molecular machinery of self-eating, plays a dual role of a tumor promoter and tumor suppressor. This mechanism affects different clinical responses in cancer cells. Autophagy is targeted for treating patients resistant to chemotherapy or radiation. Limited reports investigate the significance of autophagy in cancer therapy, the regulation of hematopoietic and leukemic stem cells and leukemia formation. In the current review, the role of autophagy is discussed in various stages of hematopoiesis including quiescence, self-renewal, and differentiation.

Microrna-130a Downregulates HCV Replication through an atg5-Dependent Autophagy Pathway

We previously identified that miR-130a downregulates HCV replication through two independent pathways: restoration of host immune responses and regulation of pyruvate metabolism. In this study, we further sought to explore host antiviral target genes regulated by miR-130a. We performed a RT² Profiler™ PCR array to identify the host antiviral genes regulated by miR-130a. The putative binding sites between miR-130a and its downregulated genes were predicted by miRanda. miR-130a and predicted target genes were over-expressed or knocked down by siRNA or CRISPR/Cas9 gRNA. Selected gene mRNAs and their proteins, together with HCV replication in JFH1 HCV-infected Huh7.5.1 cells were monitored by qRT-PCR and Western blot. We identified 32 genes that were significantly differentially expressed more than 1.5-fold following miR-130a overexpression, 28 of which were upregulated and 4 downregulated. We found that ATG5, a target gene for miR-130a, significantly upregulated HCV replication and downregulated interferon stimulated gene expression. miR-130a downregulated ATG5 expression and its conjugation complex with ATG12. ATG5 and ATG5-ATG12 complex affected interferon stimulated gene (ISG) such as MX1 and OAS3 expression and subsequently HCV replication. We concluded that miR-130a regulates host antiviral response and HCV replication through targeting ATG5 via the ATG5-dependent autophagy pathway.

MicroRNAs and the Genetic Nexus of Brain Aging, Neuroinflammation, Neurodegeneration, and Brain Trauma

Aging is a complex and integrated gradual deterioration of cellular activities in specific organs of the body, which is associated with increased mortality. This deterioration is the primary risk factor for major human pathologies, including cancer, diabetes, cardiovascular disorders, neurovascular disorders, and neurodegenerative diseases. There are nine tentative hallmarks of aging. In addition, several of these hallmarks are increasingly being associated with acute brain injury conditions. In this review, we consider the genes and their functional pathways involved in brain aging as a means of developing new strategies for therapies targeted to the neuropathological processes themselves, but also as targets for many age-related brain diseases. A single microRNA (miR), which is a short, non-coding RNA species, has the potential for targeting many genes simultaneously and, like practically all other cellular processes, genes associated with many features of brain aging and injury are regulated by miRs. We highlight how certain miRs can mediate deregulation of genes involved in neuroinflammation, acute neuronal injury and chronic neurodegenerative diseases. Finally, we review the recent progress in the development of effective strategies to block specific miR functions and discuss future approaches with the prediction that anti-miR drugs may soon be used in the clinic.

Inhibition of autophagy enhances adenosine‑induced apoptosis in human hepatoblastoma HepG2 cells

In cancer research, autophagy acts as a double‑edged sword: it increases cell viability or induces cell apoptosis depending upon the cell context and functional status. Recent studies have shown that adenosine (Ado) has cytotoxic effects in many tumors. However, the role of autophagy in Ado‑induced apoptosis is still poorly understood. In the present study, Ado‑induced apoptotic death and autophagy in hepatoblastoma HepG2 cells was investigated and the relationship between autophagy and apoptosis was identified. In the present study, it was demonstrated that Ado inhibited HepG2 cell growth in a time‑ and concentration‑dependent manner and activated endoplasmic reticulum (ER) stress, as indicated by G0/G1 cell cycle arrest, the increased mRNA and protein levels of GRP78/BiP, PERK, ATF4, CHOP, cleaved caspase‑3, cytochrome c and the loss of mitochon-drial membrane potential (ΔΨm). Ado also induced autophagic flux, revealed by the increased expression of the autophagy marker microtubule‑associated protein 1 light chain 3‑II (LC3‑II), Beclin‑1, autophagosomes, and the degradation of p62, as revealed by western blot analysis and macrophage‑derived chemokine (MDC) staining. Blocking autophagy using LY294002 notably entrenched Ado‑induced growth inhibition and cell apoptosis, as demonstrated with the increased expression of cytochrome c and p62, and the decreased expression of LC3‑II. Conversely, the autophagy inducer rapamycin alleviated Ado‑induced apoptosis and markedly increased the ΔΨm. Moreover, knockdown of AMPK with si‑AMPK partially abolished Ado‑induced ULK1 activation and mTOR inhibition, and thus reinforced CHOP expression and Ado‑induced apoptosis. These results indicated that Ado‑induced ER stress resulted in apoptosis and autophagy concurrently. The AMPK/mTOR/ULK1 signaling pathway played a protective role in the apoptotic procession. Inhibition of autophagy may effectively enhance the anticancer effect of Ado in human hepatoblastoma HepG2 cells.