MicroRNA-34a: A Versatile Regulator of Myriads of Targets in Different Cancers

Significant association of miRNA 34a with BRCA1 expression in pancreatic ductal adenocarcinoma: an insight on miRNA regulatory pathways in the Pakistani population

BACKGROUND

Pancreatic Ductal Adenocarcinoma (PDAC) is among the most aggressive cancers, characterized by high mortality rates. Studies on various cancers across the globe indicate that regulatory miRNAs play a vital role in cellular signaling. However, the expression and interactions of these miRNAs in the Pakistani patients with PDAC is yet to be explored. Here, we aim to investigate a panel of four regulatory miRNAs (miRNA 34a, 30b, 142 and 137) in PDAC and their interaction with selected target proteins in the signaling pathway (KRAS, p53, BRCA1, APC).

METHODS

We conducted a study on 109 PDAC patients to analyze the selected miRNAs and protein targets. Formalin Fixed Paraffin Embedded (FFPE) tumor samples were obtained from the hospital's department of histopathology. After confirmation of diagnosis and appropriate tumor content, tissues were processed for RNA extraction. Based on the acceptable quality and quantity of RNA, 43 samples were proceeded for qRT-PCR. Relative expression of the miRNAs was determined through 2-[ΔΔCt] method. Further, FFPE tumor blocks were used to perform tissue sectioning followed by immunohistochemistry experiments. Stained slides were scored independently by two pathologists according to set criteria.

RESULTS

Expression profiles revealed that miRNA 34a, 30b, and 142 showed high expression in approximately 69-70% of cases, while miRNA 137 had a lower high expression frequency (53.4%). Among protein biomarkers, KRAS, BRCA1, and APC were predominantly expressed, with high expression levels observed in 79.1%, 69.8%, and 51.2% of cases, respectively, whereas p53 showed positive expression in only 34.9% of cases. Statistical analysis showed that expression of miRNA 34a was significantly associated with the expression of BRCA1 (p = 0.034). No significant associations were observed for KRAS, p53, or APC with the selected miRNAs. Moreover, the expression of miRNA 34a independently showed significant association with miRNA 30b (p = 0.000) and miRNA 137 (p = 0.001). None of the miRNA showed an association with the overall survival, patient demographics or the clinicopathological characteristics.

CONCLUSION

Our study highlights a potential bi-directional regulatory relationship between BRCA1 and miRNA 34a, suggesting that miRNA 34a may both respond to and influence BRCA1 activity within cellular signaling pathways. This complex interaction points to a layered regulatory network that could play a crucial role in tumor suppression in PDAC, underscoring the therapeutic potential of targeting this miRNA-protein crosstalk.

Tumor Suppressor miR-34a: Potential Biomarker of TACE Response in HCC

PURPOSE

TACE induces variable systemic effects by producing factors that promote inflammation, oncogenesis, and angiogenesis. Here we compare concentrations of microRNAs (miR-21, miR-210 and miR-34a) and vascular endothelial growth factor (VEGF) in hepatocellular carcinoma (HCC) patients undergoing TACE with degradable (DSM) and nondegradable (DEB) particles and potential use of these biomarker changes for prediction of patient outcomes.

MATERIALS AND METHODS

Overall, 52 patients with HCC treated with DSM TACE (24 patients) and DEB TACE (28 patients) were included in this prospective study. Concentrations of studied biomarkers were measured from blood plasma preprocedurally, immediately (< 90 min) postprocedurally, and 24-h after TACE. Levels were compared between DSM and DEB TACE and correlated with treatment response six and 12 months after the first TACE.

RESULTS

Both DSM and DEB TACE elevated plasma levels of miR-21, miR-34a, and miR-210 at 24 h post-procedure compared to baseline levels (FC 1.25-4.0). MiR-34a elevation immediately after TACE was significantly associated with nonprogressive disease compared to those with progressive disease at both six months (FCa: p = 0.014) and 12 months (FCa: p = 0.029) post-TACE. No significant biomarker changes were found between the embolization particle groups. However, VEGF levels showed a decrease only in the DSM TACE group (FC24: p =  < 0.001).

CONCLUSION

Embolization particle type did not significantly impact miRNA or VEGF changes post-TACE. However, miR-34a elevation immediately after the procedure predicts better patient outcome and may prove useful as a biomarkers for the monitoring of clinical outcomes.

LEVEL OF EVIDENCE

Level 3 Prospective cohort study.

microRNAs expression profile in phyllodes tumors of the breast

Proliferation of both stromal and epithelial components is a characteristic of fibroepithelial cancers of the breast. Certain fibroepithelial tumors of the breast, such as fibradenomas and phyllodes tumors, are challenging to distinguish and categorize. To find biomarkers for early diagnosis and improved disease management, it is crucial to deepen our understanding of the molecular pathogenesis pathways and tumor biology of PTs. It has been demonstrated that microRNAs (miRNAs) have significant roles in cancers; the expression pattern of miRNAs can help with cancer categorization and treatment. In contrast, little is understood about miRNAs in breast fibroepithelial cancers. This study was conducted retrospectively with the goal of assessing the expression of six mature miRNAs (hsa-miR-21, hsa-miR-155, hsa-miR-182, hsa-miR-34a, hsa-miR-148a, and hsa-miR-205) in breast fibroepithelial cancers using real-time PCR and predicting these miRNAs' targets using computational techniques. This study comprised 64 patients in total-55 with phyllodes tumors and 9 with fibroadenoma. The research was carried out at the Farhat Hached University Hospital's pathology department in Tunisia. These particular miRNAs expression levels were evaluated via qRT-PCR, and in silico techniques were utilized to predict potential miRNA targets. Analysis of miRNA expression in fibroadenoma and phyllodes tumor tissues revealed that miR-21, miR-155 and miR-182 were upregulated in PTs compared to fibroadenoma and normal tissues. We reported that miR-34a, miR-148a and miR-205 were downregulated in both borderline and malignant PTs compared to fibroadenoma and normal tissue. In silico miRNA target prediction suggested the involvement of these molecules in a wide context of cell signaling pathways.

Dysregulation of Non-Coding RNAs: Roles of miRNAs and lncRNAs in the Pathogenesis of Multiple Myeloma

The dysregulation of non-coding RNAs (ncRNAs), specifically microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), leads to the development and advancement of multiple myeloma (MM). miRNAs, in particular, are paramount in post-transcriptional gene regulation, promoting mRNA degradation and translational inhibition. As a result, miRNAs can serve as oncogenes or tumor suppressors depending on the target genes. In MM, miRNA disruption could result in abnormal gene expression responsible for cell growth, apoptosis, and other biological processes pertinent to cancer development. The dysregulated miRNAs inhibit the activity of tumor suppressor genes, contributing to disease progression. Nonetheless, several miRNAs are downregulated in MM and have been identified as gene regulators implicated in extracellular matrix remodeling and cell adhesion. miRNA depletion potentially facilitates the tumor advancement and resistance of therapeutic drugs. Additionally, lncRNAs are key regulators of numerous cellular processes, such as gene expression, chromatin remodeling, protein trafficking, and recently linked MM development. The lncRNAs are uniquely expressed and influence gene expression that supports MM growth, in addition to facilitating cellular proliferation and viability via multiple molecular pathways. miRNA and lncRNA alterations potentially result in anomalous gene expression and interfere with the regular functioning of MM. Thus, this review aims to highlight the dysregulation of these ncRNAs, which engender novel therapeutic modalities for the treatment of MM.

MIR34A modulates lens epithelial cell apoptosis and cataract development via the HK1/caspase 3 signaling pathway

Cataracts are the leading cause of blindness in the world. Age is a major risk factor for cataracts, and with increasing aging, the burden of cataracts will grow, but the exact details of cataractogenesis remain unclear. A recent study showed that microRNA-34a (MIR34A) is involved in the development of cataracts, but the underlying pathogenesis remains obscure. Here, our results of microRNA target prediction showed that hexokinase 1 (HK1) is one of the genes targeted by MIR34A. Based on this finding, we focused on the function of MIR34A and HK1 in the progress of cataracts, whereby the human lens epithelial cell line SRA01/04 and mouse lens were treated with MIR34A mimics and HK1 siRNA. We found that HK1 mRNA is a direct target of MIR34A, whereby the high expression of MIR34A in the cataract lens suppresses the expression of HK1. In vitro, the upregulation of MIR34A together with the downregulation of HK1 inhibits the proliferation, induces the apoptosis of SRA01/04 cells, and accelerates the opacification of mouse lenses via the HK1/caspase 3 signaling pathway. In summary, our study demonstrates that MIR34A modulates lens epithelial cell (LEC) apoptosis and cataract development through the HK1/caspase 3 signaling pathway.

Apoptosis-targeted gene therapy for non-small cell lung cancer using chitosan-poly-lactic-co-glycolic acid -based nano-delivery system and CASP8 and miRs 29A-B1 and 34A

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide, with resistance to apoptosis being a major driver of therapeutic resistance and aggressive phenotype. This study aimed to develop a novel gene therapy approach for NSCLC by targeting resistance to apoptosis. Loss of function mutations of caspase 8 (CASP8) and downregulation of microRNAs (miRs) 29A-B1 and 34A were identified as key contributors to resistance to apoptosis in NSCLC. A biodegradable polymeric nano-gene delivery system composed of chitosan-poly-lactic-co-glycolic acid was formulated to deliver initiator CASP8 and miRs 29A-B1 and 34A. The nano-formulation efficiently encapsulated the therapeutic genes effectively internalized into NSCLC cells and induced significant apoptosis. Evaluation of the nano-formulation in A549 tumor spheroids showed a significant increase in apoptosis within the core of the spheroids, suggesting effective penetration into the spheroid structures. We provide a novel nano-formulation that demonstrate therapeutic potential for suicidal gene therapy in NSCLC.

Signaling pathways in cancer metabolism: mechanisms and therapeutic targets

A wide spectrum of metabolites (mainly, the three major nutrients and their derivatives) can be sensed by specific sensors, then trigger a series of signal transduction pathways and affect the expression levels of genes in epigenetics, which is called metabolite sensing. Life body regulates metabolism, immunity, and inflammation by metabolite sensing, coordinating the pathophysiology of the host to achieve balance with the external environment. Metabolic reprogramming in cancers cause different phenotypic characteristics of cancer cell from normal cell, including cell proliferation, migration, invasion, angiogenesis, etc. Metabolic disorders in cancer cells further create a microenvironment including many kinds of oncometabolites that are conducive to the growth of cancer, thus forming a vicious circle. At the same time, exogenous metabolites can also affect the biological behavior of tumors. Here, we discuss the metabolite sensing mechanisms of the three major nutrients and their derivatives, as well as their abnormalities in the development of various cancers, and discuss the potential therapeutic targets based on metabolite-sensing signaling pathways to prevent the progression of cancer.

Epigenetic programing of cancer stemness by transcription factors-non-coding RNAs interactions

Cancer 'stemness' is fundamental to cancer existence. It defines the ability of cancer cells to indefinitely perpetuate as well as differentiate. Cancer stem cell populations within a growing tumor also help evade the inhibitory effects of chemo- as well as radiation-therapies, in addition to playing an important role in cancer metastases. NF-κB and STAT-3 are representative transcription factors (TFs) that have long been associated with cancer stemness, thus presenting as attractive targets for cancer therapy. The growing interest in non-coding RNAs (ncRNAs) in the recent years has provided further insight into the mechanisms by which TFs influence cancer stem cell characteristics. There is evidence for a direct regulation of TFs by ncRNAs, such as, microRNAs (miRNAs), long non-coding RNAs (lncRNAs) as well as circular RNAs (circRNAs), and vice versa. Additionally, the TF-ncRNAs regulations are often indirect, involving ncRNA-target genes or the sponging of other ncRNA species by individual ncRNAs. The information is rapidly evolving and this review provides a comprehensive review of TF-ncRNAs interactions with implications on cancer stemness and in response to therapies. Such knowledge will help uncover the many levels of tight regulations that control cancer stemness, providing novel opportunities and targets for therapy in the process.

Nanomedicine for autophagy modulation in cancer therapy: a clinical perspective

In recent years, progress in nanotechnology provided new tools to treat cancer more effectively. Advances in biomaterials tailored for drug delivery have the potential to overcome the limited selectivity and side effects frequently associated with traditional therapeutic agents. While autophagy is pivotal in determining cell fate and adaptation to different challenges, and despite the fact that it is frequently dysregulated in cancer, antitumor therapeutic strategies leveraging on or targeting this process are scarce. This is due to many reasons, including the very contextual effects of autophagy in cancer, low bioavailability and non-targeted delivery of existing autophagy modulatory compounds. Conjugating the versatile characteristics of nanoparticles with autophagy modulators may render these drugs safer and more effective for cancer treatment. Here, we review current standing questions on the biology of autophagy in tumor progression, and precursory studies and the state-of-the-art in harnessing nanomaterials science to enhance the specificity and therapeutic potential of autophagy modulators.

Anti-Cancer Effects of Queen Bee Acid (10-Hydroxy-2-Decenoic Acid) and Its Cellular Mechanisms against Human Hepatoma Cells

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common form of liver cancer that occurs in hepatocytes. Although many chemical drugs, e.g., cisplatin, methotrexate, taxis, and doxorubicin are used to treat HCC, there have been numerous reports related to the side effects of these drugs (e.g., emerging drug resistance, bone marrow failure, and gastrointestinal disorders). These issues led scientists to search for the novel anti-cancer drugs, mainly in natural products with greater efficiency and less toxicity. The current survey was intended to assess the anti-cancer effects of queen bee acid (10-Hydroxy-2-Decenoic Acid, 10-HDA) and its cellular mechanisms against the human hepatoma cell line HepG2.

MATERIALS AND METHODS

The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay was used to evaluate the effect of 10-HDA on the viability of HepG2 cells. The initial and late apoptosis in the HepG2 cells treated with 10-HDA were assessed by the Annexin-V (AV) assay. The level of the gene and protein expression of some apoptosis genes (e.g., caspase-3, Bcl-2-associated X protein (BAX), and B-cell lymphoma protein 2 (Bcl-2)), Poly (ADP-ribose) polymerases (PARP), and miRNA-34a (miR-34a), were measured by real-time PCR and Western blot.

RESULTS

The obtained findings revealed that HepG2 cell viability was markedly reduced (p < 0.01) following exposure to 10-HDA in a dose-dependent matter. The calculated half maximal cytotoxic concentration (CC50) value of 10-HDA was 59.6 µg/mL for HepG2 cells, while this value for normal THLE-3 cells was 106.4 µg/mL. We found that 10-HDA markedly elevated (p < 0.01) the percentage of necrotic and apoptotic cells from 0.94 to 9.7 and 27.6%, respectively. The real-time PCR results showed that the expression levels of the caspase-3, Bax, and miR-34a genes were significantly (p < 0.001) elevated. Contrary to these results, a significant (p < 0.01) reduction in the expression level of the Bcl2 gene was observed. The levels of protein expression of Caspase-3, PARP, and Bax were markedly elevated following exposure of HepG2 cells to 10-HDA at ¼ CC50, ½ CC50, and CC50. The level of protein expression of Bcl-2 was markedly reduced following exposure of HepG2 cells to 10-HDA at ¼ CC50, ½ CC50, and CC50 (p < 0.01).

CONCLUSION

The current results confirmed the potent in vitro cytotoxic effects of 10-HDA on HepG2 cells with no significant cytotoxic effects on normal cells. Although its mechanisms of action have not been fully studied, the induction of apoptosis via different pathways was determined as one of the principle mechanisms of action of 10-HDA against HepG2 cells. Nevertheless, additional surveys must be performed to clearly understand the mechanisms of action and safety of this fatty acid.

Mechanisms Controlling MicroRNA Expression in Tumor

MicroRNAs (miRNAs) are widely present in many organisms and regulate the expression of genes in various biological processes such as cell differentiation, metabolism, and development. Numerous studies have shown that miRNAs are abnormally expressed in tumor tissues and are closely associated with tumorigenesis. MiRNA-based cancer gene therapy has consistently shown promising anti-tumor effects and is recognized as a new field in cancer treatment. So far, some clinical trials involving the treatment of malignancies have been carried out; however, studies of miRNA-based cancer gene therapy are still proceeding slowly. Therefore, furthering our understanding of the regulatory mechanisms of miRNA can bring substantial benefits to the development of miRNA-based gene therapy or other combination therapies and the clinical outcome of patients with cancer. Recent studies have revealed that the aberrant expression of miRNA in tumors is associated with promoter sequence mutation, epigenetic alteration, aberrant RNA modification, etc., showing the complexity of aberrant expression mechanisms of miRNA in tumors. In this paper, we systematically summarized the regulation mechanisms of miRNA expression in tumors, with the aim of providing assistance in the subsequent elucidation of the role of miRNA in tumorigenesis and the development of new strategies for tumor prevention and treatment.

Mir-34a: a regulatory hub with versatile functions that controls osteosarcoma networks

Osteosarcoma (OS) is one of the most prevalent and highly aggressive bone malignancies. The treatment strategies of OS is under standard regimens, including surgical resection, chemotherapy, and other adjuvant therapy. However, the 5-year survival rate is still unsatisfactory. Previous studies have demonstrated that the expression of miR-34a decreases in osteosarcoma, which is involved in regulating numerous genes directly or indirectly at the post-transcriptional level and other pathways. Thus, miR-34a plays an important role in mediating OS cell proliferation, differentiation, migration, and apoptosis, and might be a pivotal biomarker for OS with diagnostic and therapeutic potentials. In this review, we aim to summarize the relationship between miR-34a and OS, with an emphasis on the specific mechanisms in OS development referring to miR-34a. Moreover, the potential role of miR-34a as a diagnostic, prognostic, and therapeutic candidate for OS would be presented in detail. However, the molecular mechanisms related to miR-34a and OS remain elusive, and more investigations are needed to reach a comprehensive understanding.

Binding sites of miRNA on the overexpressed genes of oral cancer using 7mer-seed match

The microRNAs having a length of ~ 19-22 nucleotides are the small, non-coding RNAs. The evolution of microRNAs in many disorders may hold the key to tackle complex challenges. Oral cancer belongs to the group of head and neck cancer. It occurs in the mouth region that appears as an ulcer. In this study, we collected information on the overexpressed genes of oral cancer. The coding sequences of the genes were derived from NCBI and the entire set of human microRNAs present in miRBASE 21 was retrieved. The human microRNAs that can target the overexpressed genes of oral cancer were determined with the aid of our in-house software. The interaction between microRNAs and the overexpressed genes was evaluated with 7mer-m8 model of microRNA targeting. The genes DKK1 and APLN paired with only one miRNA i.e., miR-447 and miR-6087, respectively. But the genes INHBA and MMP1 were found to be targeted by 2 miRNAs, while the genes FN1, FAP, TGFPI, COL4A1, COL4A2, and LOXL2 were found to be targeted by 16, 5, 9, 18, 29, and 11 miRNAs. Subsequently, several measures such as free energy, translation efficiency, and cosine similarity metric were used to estimate the binding process. It was found that the target region's stability was higher than the upstream and downstream zones. The overexpressed genes' GC contents were calculated, revealing that the codons in target miRNA region were overall GC rich as well as GC3 rich. Lastly, gene ontology was performed to better understand each gene's involvement in biological processes, molecular function, and cellular component. Our study showed the role of microRNAs in gene repression, which could possibly aid in the prognosis and diagnosis of oral cancer.

Characterization of miR-34a-Induced Epithelial-Mesenchymal Transition in Non-Small Lung Cancer Cells Focusing on p53

Background: Epithelial–mesenchymal transition (EMT), a phenotypic conversion of the epithelial to mesenchymal state, contributes to cancer progression. Currently, several microRNAs (miRNAs) are associated with EMT-mediated cancer progression, but the contribution of miR-34a to EMT in cancer cells remains controversial. The present study aimed to clarify the role of miR-34a in the EMT-related phenotypes of human non-small cell lung cancer (NSCLC) cell lines, A549 (p53 wild-type) and H1299 (p53-deficient). Methods: The miR-34a mimic and p53 small interfering RNA (siRNA) were transfected into the cells using Lipofectamine, and the obtained total RNA and cell lysates were used for real-time polymerase chain reaction and Western blotting analysis, respectively. Results: The introduction of the miR-34a mimic led to an increase in the mRNA and protein expression levels of α-smooth muscle actin (α-SMA), a mesenchymal marker gene, in A549, but not in H1299 cells. Additionally, miR-34a-induced the upregulation of p53 activity and migration was observed in A549, but not in H1299 cells. However, under the p53-knockdown condition, only α-SMA upregulation by miR-34a was abolished. Conclusion: These findings indicate a close relationship between p53 and miR-34a-induced EMT in p53-wild type NSCLC cells, which provides novel insights about the role of miR-34a in EMT-like phenotypic changes in NSCLC.

Combination therapy with miR-34a and doxorubicin synergistically induced apoptosis in T-cell acute lymphoblastic leukemia cell line

MicroRNAs are identified to take actively part in the development of different cancers. Reduced expression of tumor suppressor miRNAs leads to cancer cell development, so restoring the expression of these miRNAs can be an appropriate treatment option for cancer. Due to the heterogeneity of cancer cells, single-drug therapy often results in drug resistance. Therefore, the combination of chemotherapy with miRNA can be a powerful strategy for cancer treatment. In the current investigation, miR-34a mimic, and negative control were purchased and transfected using jetPEI reagents. Then the synergic effects of miR-34a in combination with doxorubicin were investigated on cell death of acute T-cell lymphoblastic leukemia Jurkat cell line, as well as the expression of some genes including Caspase-3, Bcl-2, and p53 which are involved in apoptosis. Our outcomes showed that this combination remarkably reduced the expression of the Bcl-2 gene, the target gene of miR-34a. According to the results of the MTT assay, the survival rate was significantly decreased compared to the untreated cells. Results of the flow cytometry assay and DAPI staining demonstrated an increased apoptosis rate of Jurkat cells in combination therapy. Moreover, cell cycle arrest was observed at the G2/M phase in cells that were treated with miR-34a/doxorubicin. Most importantly, we showed that the transfection of the Jurkat cells with miR-34a increased the sensitivity of these cells to doxorubicin. Furthermore, the combination of miR-34a and doxorubicin drug effectively increased apoptosis of treated cells. Therefore, this method can be used as an impressive treatment for T-ALL.

Epigenetic regulation of immunosuppressive tumor-associated macrophages through dysregulated microRNAs

Macrophages are immune cells that play different roles under different physiological conditions. They are present in all tissues where they primarily protect from bacteria and pathogens in addition to assisting in tissue repair. During tumor progression, macrophages can exert contrasting effects based on the M1 vs. M2 polarization. The M2 macrophages support tumor growth through mechanisms that help suppress immune responses and/or circumvent immune-surveillance. A number of such mechanisms such as production of IL-10 and arginase, and expression of PD-L1, V-domain Ig suppressor of T cell activation and B7 family molecule B7-H4 are now believed central to the immunosuppressive effects of tumor-associated macrophages (TAMs). Emerging data has identified epigenetic regulation of these immunosuppressive mechanisms by small non-coding RNAs, the microRNAs (miRNAs). This review discusses the available literature on the subject, including the exosomes mediated transfer of miRNAs between cancer cells and the macrophages within the tumor microenvironment. A number of miRNAs are now believed to be involved in TAMs' production of IL-10 and expression of PD-L1 while the information on such regulation of other immunosuppressive mechanisms is slowly emerging. A better understanding of epigenetic regulation of macrophages-mediated immunosuppressive effect can help identify novel targets for therapy and aid the design of future studies aimed at sensitizing tumors to immune responses.

Puerarin facilitates osteogenesis in steroid-induced necrosis of rabbit femoral head and osteogenesis of steroid-induced osteocytes via miR-34a upregulation

The present study investigated the effect of puerarin on promoting the osteogenesis in steroid-induced necrosis of the femoral head (SONFH). New Zealand rabbits were administrated with horse serum and methylprednisolone (MPS) for establishing SONFH in vivo model, which was then treated with puerarin treatment. Histo-morphological changes in the femoral head were examined by hematoxylin-eosin staining. Osteoblasts were isolated from healthy rabbits and treated by individual or combined administration of dexamethasone and puerarin. Osteoblast viability was measured by CCK-8 assay. Mineralized nodule formation was evaluated by alizarin red assay. Expressions of RUNX family transcription factor 2 (RUNX2), Type-I collagen α 1 (COL1A1), ALP and miR-34a in the femoral head were determined by qRT-PCR and Western blot. Puerarin attenuated the effect of SONFH on promoting histopathological abnormalities and counteracted SONFH inhibition on the expressions of ALP, RUNX2, COL1A1 and miR-34a in the rabbits. Rabbit osteoblasts were successfully isolated, as they showed red mineralized nodules. Dexamethasone exposure decreased osteoblast viability, which was increased by puerarin treatment. Furthermore, puerarin treatment attenuated dexamethasone-induced inhibition on the viability, osteoblastic differentiation, and the expressions of ALP, RUNX2, COL1A1 and miR-34a in the osteoblasts. Puerarin facilitated osteogenesis of steroid-induced necrosis of rabbit femoral head and osteogenesis of steroid-induced osteocytes via miR-34a upregulation.

Nanocell-mediated delivery of miR-34a counteracts temozolomide resistance in glioblastoma

BACKGROUND

Glioblastoma is the most common primary brain tumor and remains uniformly fatal, highlighting the dire need for developing effective therapeutics. Significant intra- and inter-tumor heterogeneity and inadequate delivery of therapeutics across blood-brain barrier continue to be significant impediments towards developing therapies which can significantly enhance survival. We hypothesize that microRNAs have the potential to serve as effective therapeutics for glioblastoma as they modulate the activity of multiple signaling pathways, and hence can counteract heterogeneity if successfully delivered.

METHODS

Using a computational approach, we identified microRNA-34a as a microRNA that maximally reduces the activation status of the three core signaling networks (the receptor tyrosine kinase, p53 and Rb networks) that have been found to be deregulated in most glioblastoma tumors. Glioblastoma cultures were transfected with microRNA-34a or control microRNA to assess biological function and therapeutic potential in vitro. Nanocells were derived from genetically modified bacteria and loaded with microRNA-34a for intravenous administration to orthotopic patient-derived glioblastoma xenografts in mice.

RESULTS

Overexpression of microRNA-34a strongly reduced the activation status of the three core signaling networks. microRNA-34a transfection also inhibited the survival of multiple established glioblastoma cell lines, as well as primary patient-derived xenograft cultures representing the proneural, mesenchymal and classical subtypes. Transfection of microRNA-34a enhanced temozolomide (TMZ) response in in vitro cultures of glioblastoma cells with primary TMZ sensitivity, primary TMZ resistance and acquired TMZ resistance. Mechanistically, microRNA-34a downregulated multiple therapeutic resistance genes which are associated with worse survival in glioblastoma patients and are enriched in specific tumor spatial compartments. Importantly, intravenous administration of nanocells carrying miR-34a and targeted to epidermal growth factor receptor (EGFR) strongly enhanced TMZ sensitivity in an orthotopic patient-derived xenograft mouse model of glioblastoma.

CONCLUSIONS

Targeted bacterially-derived nanocells are an effective vehicle for the delivery of microRNA-34a to glioblastoma tumors. microRNA-34a inhibits survival and strongly sensitizes a wide range of glioblastoma cell cultures to TMZ, suggesting that combination therapy of TMZ with microRNA-34a loaded nanocells may serve as a novel therapeutic approach for the treatment of glioblastoma tumors.

miR-34a-5p might have an important role for inducing apoptosis by down-regulation of SNAI1 in apigenin-treated lung cancer cells

Apigenin is a flavonoid with antioxidant and anticancer effects. It has been reported that apigenin inhibits proliferation, migration, and invasion and induces apoptosis in cultured lung cancer cells. However, there is little information on the involvement of microRNAs (miRNAs) in its effects. miRNA microarray analysis and polymerase-chain-reaction analysis of miRNAs revealed that treatment of human lung cancer A549 cells with apigenin up-regulated the level of miR-34a-5p. Furthermore, mRNA microarray analysis and the results of three microRNA target prediction tools showed that Snail Family Transcriptional Repressor 1 (SNAI1), which inhibits the induction of apoptosis, had its mRNA expression down-regulated in A549 cells treated with apigenin. Our findings suggest that apigenin might induce apoptosis by down-regulation of SNAI1 through up-regulation of miR-34a-5p in A549 cells.

Melatonin inhibits proliferation and viability and promotes apoptosis in colorectal cancer cells via upregulation of the microRNA-34a/449a cluster

Colorectal cancer (CRC) has a significant burden on healthcare systems worldwide, and is associated with high morbidity and mortality rates in patients. In 2020, the estimated new cases of colon cancer in the United States are 78,300 in men and 69,650 in women. Thus, developing effective and novel alternative agents and adjuvants with reduced side effects is important to reduce the lethality of the disease and improve the quality of life of patients. Melatonin, a pineal hormone that possesses numerous physiological functions, including anti-inflammatory and antitumor activities, can be found in various tissues, including the gastrointestinal tract. Melatonin exerts anticarcinogenic effects via various mechanisms; however, the identified underlying molecular mechanisms do not explain the full breadth of anti-CRC effects mediated by melatonin. MicroRNAs (miRs) serve critical roles in tumorigenesis, however, whether melatonin can inhibit CRC by regulating miRs is not completely understood. In the present study, the roles and mechanism underlying melatonin in CRC were investigated. The proliferation of human CRC cells was tested by CCK8, EDU and colony formation assay. The apoptosis of cancer cells was detected by flow cytometry and western blotting. A xenograft mouse model was constructed and the proliferation and apoptosis of tumor tissue was detected by Ki-67 and TUNEL staining assay respectively. Reverse transcription-quantitative PCR and western blotting were performed to measure the regulation of miRs on mRNA, and the dual-luciferase report analysis experiment was used to verify the direct target genes of miRs. Compared with the control group, melatonin inhibited viability and proliferation, and induced apoptosis in CRC cells. Additionally, the effect of melatonin in a xenograft mouse model was assessed. Compared with the control group, melatonin significantly enhanced the expression levels of the miR-34a/449a cluster, reduced CRC cell proliferation and viability, and increased CRC cell apoptosis. Finally, the dual-luciferase reporter assay indicated that Bcl-2 and Notch1 were the target mRNAs of the miR-34a/449a cluster. To the best of our knowledge, the present study was the first to suggest that melatonin inhibited proliferation and viability, and promoted apoptosis in CRC cells via upregulating the expression of the miR-34a/449a cluster in vitro and in vivo. Therefore, melatonin may serve as a potential therapeutic for CRC.

Current developments of targeting the p53 signaling pathway for cancer treatment

p53 is one of the most well-studied tumor suppressors. It is mutated or deleted in half of all cancers. In the other half carrying wild type p53, the p53 signaling pathway is disrupted by abnormalities of other components in the pathway. Due to its paramount role in tumor suppression, p53 has attracted great interest in drug development as any clinically successful therapeutic agent to target the p53 pathway will save millions of lives. However, designing therapeutics targeting the pathway has been extremely challenging, despite more than forty years of research. This review will summarize past and current efforts of developing p53-based gene therapy and targeted therapies for cancer treatment. In addition, the current efforts of exploiting the immunogenicity of p53 protein for cancer immunotherapy will be reviewed. Challenges and future directions for targeting the p53 pathway will be discussed.

Prognostic Stratification of Bladder Cancer Patients with a MicroRNA-based Approach

Robust non-invasive tests for prognostic stratification of bladder cancer (BCa) patients are in high demand. Following a comprehensive analysis of studies on BCa, we selected a panel of 29 microRNAs (miRNAs) and analyzed their levels in urine and plasma samples in a prospective cohort of 63 BCa patients (32 at high risk of recurrence and 31 low-risk cases) and 37 healthy controls using RT-qPCR. To design an assay suitable for large-scale testing, we applied a hierarchical pipeline to select the miRNAs that were not affected by confounding factors such as haematuria and urine specific gravity, and exceeded stringent cut-off criteria (fold change >2.5 and p-value < 0.005). Using a two-step decision tree based on the urine levels of miR-34a-5p, miR-200a-3p and miR-193a-5p, normalized against miR-125b-5p, patients could be classified as high- or low-risk with a sensitivity of 0.844, specificity of 0.806 and accuracy of 0.825. Furthermore, univariate Cox proportional hazards regression analyses indicated that increased urine levels of miR-29a-3p, miR-34a-5p, miR-193a-5p, miR-200c-3p, miR-205-5p and miR-532-5p were associated with a shorter event-free survival (hazard ratios > 3.1, p-value < 0.05). Taken together, our findings suggest that measuring the urine levels of these miRNAs could provide a novel cost-effective, noninvasive test for risk assessment of BCa patients.

The roles of non-coding RNAs in vascular calcification and opportunities as therapeutic targets

Vascular calcification (VC) is characterized by an accumulation of calcium phosphate crystals inside the vessel wall. VC is often associated with diabetes, chronic kidney disease (CKD), atherosclerosis, and cardiovascular disease (CVD). Even though the number of patients with VC remains prevalent, there are still no approved therapies for the treatment of VC. Since the pathogenesis of VC is diverse and involves multiple factors and mechanisms, it is critical to reveal the novel mechanisms involved in VC. Although protein-coding RNAs involved in VC have been extensively studied, the roles of non-coding RNAs (ncRNAs) are not yet fully understood. The field of ncRNAs has recently received attention, and accumulating evidence from studies in VC suggests that ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play an important role in the regulation of VC. NcRNAs can modulate VC by acting as promoters or inhibitors and may be useful in the clinical diagnosis and treatment of VC. In this article, we review and discuss ncRNAs that regulate VC and present the therapeutic implications of these ncRNAs.

Nanomaterials for Autophagy-Related miRNA-34a Delivery in Cancer Treatment

Autophagy is an evolutionary conserved physiological process with a fundamental role during development, differentiation, and survival of eukaryotic cells. On the other hand, autophagy dysregulation is observed in many pathological conditions, including cancer. In particular, tumor growth and progression are accompanied and promoted by increased autophagy that allows cancer cells to escape apoptosis and to proliferate also in harsh microenvironments. It is, therefore, clear that the impairment of the autophagic process may represent a valid strategy to inhibit or reduce cancer growth and progression. Among the plethora of molecular players controlling cancer growth, a group of small endogenous noncoding RNAs called microRNAs (miRNAs) has recently emerged. In fact, miRNAs can act as either oncogenes or oncosuppressors depending on their target genes. Moreover, among miRNAs, miRNA-34a has been connected with both tumor repression and autophagy regulation, and its expression is frequently lost in many cancers. Therefore, enforced expression of miRNA-34a in cancer cells may represent a valid strategy to reduce cancer growth. However, such strategy is limited by the fast biodegradation and short half-life of miRNA-34a and by the lack of an efficient intracellular delivery system. The following review describes the autophagic process and its role in cancer as well as the role of miRNAs in general and miRNA-34a in particular in regulating tumor growth by modulating autophagy. Finally, we describe the use of nanoparticles as a promising strategy to selectively deliver miRNA-34a to tumor cells for therapeutic and diagnostic purposes.

Identification of MicroRNAs With In Vivo Efficacy in Multiple Myeloma-related Xenograft Models

BACKGROUND/AIM

Multiple myeloma is a B-cell neoplasm, which can spread within the marrow of the bones forming many small tumors. In advanced disease, multiple myeloma can spread to the blood as plasma cell leukemia. In some cases, a localized tumor known as plasmacytoma is found within a single bone. Despite the approval of several agents such as melphalan, corticosteroids, proteasome inhibitors, thalidomide-based immuno-modulatory agents, histone deacetylase inhibitors, a nuclear export inhibitor and monoclonal antibodies daratuzumab and elatuzumab, the disease presently remains uncurable.

MATERIALS AND METHODS

In order to define new targets and treatment modalities we searched the literature for microRNAs, which increase or inhibit in vivo efficacy in multiple-myeloma-related xenograft models.

RESULTS AND CONCLUSION

We identified six up-regulated and twelve down-regulated miRs, which deserve further preclinical validation.

Long non-coding RNA TUG1 knockdown hinders the tumorigenesis of multiple myeloma by regulating the microRNA-34a-5p/NOTCH1 signaling pathway

Multiple myeloma (MM) is a serious health issue in hematological malignancies. Long non-coding RNA taurine-upregulated gene 1 (TUG1) has been reported to be highly expressed in the plasma of MM patients. However, the functions of TUG1 in MM tumorigenesis along with related molecular basis are still undefined. In this study, increased TUG1 and decreased microRNA-34a-5p (miR-34a-5p) levels in MM tissues and cells were measured by the real-time quantitative polymerase reaction assay. The expression of relative proteins was determined by the Western blot assay. TUG1 knockdown suppressed cell viability, induced cell cycle arrest and cell apoptosis in MM cells, as shown by Cell Counting Kit-8 and flow cytometry assays. Bioinformatics analysis, luciferase reporter assay, and RNA pull-down assay indicated that miR-34a-5p was a target of TUG1 and directly bound to notch receptor 1 (NOTCH1), and TUG1 regulated the NOTCH1 expression by targeting miR-34a-5p. The functions of miR-34a-5p were abrogated by TUG1 upregulation. Moreover, TUG1 loss impeded MM xenograft tumor growth in vivo by upregulating miR-34a-5p and downregulating NOTCH1. Furthermore, TUG1 depletion inhibited the expression of Hes-1, Survivin, and Bcl-2 protein in MM cells and xenograft tumors. TUG1 knockdown inhibited MM tumorigenesis by regulating the miR-34a-5p/NOTCH1 signaling pathway in vitro and in vivo, deepening our understanding of the TUG1 function in MM.

MicroRNA-34a deficiency leads to impaired wound closure by augmented inflammation in mice

Background

Proper inflammation resolution is critical for cutaneous wound healing and disordered inflammation resolution results in chronic nonhealing wounds. However, the cellular and molecular mechanisms for resolution of inflammation during skin wound healing are not well understood. MicroRNA-34a is regarded as one tumor suppressor with complexed immune regulatory effects, yet its role during skin wound repair is still unclear.

Methods

Circular full thickness excisional wounds were made on the dorsal skin of C57 mice and miR-34a expression pattern was examined by real time RT-PCR and in situ hybridization. The wound healing rates and histologic morphometric analysis were quantified and compared between wounds treated with antagomir-34a and autologous control antagomir-NC wounds, as well as wounds between miR-34a knockout (KO) and wild type (WT) mice. Immunohistochemistry (IHC) for both MPO and F4/80 were performed to examine the infiltrative neutrophils and macrophages in wounds from miR-34a KO and WT mice. Cytokines including IL-1β, IL-6, TNF-α and IL-10, were detected and analyzed by real time RT-PCR during wound healing. IHC for IL-6 and p-STAT3 were quantified, and WB for p-STAT3 and IL-6R were examined in wounds of miR-34a KO and WT mice.

Results

We found miR-34a was significantly downregulated in the inflammatory phase and back to normal levels in the proliferative phase. Both topical knockdown wounds miR-34a levels by antagomir gel and systematic knockout miR-34a using KO mice resulted in impaired wound healing with delayed re-epithelialization and augmented inflammation. IHC results indicated that there were more residual infiltrative inflammatory cells in the proliferative phase. Moreover, over-activated IL-6/STAT3 signal pathway was identified in the wounds of miR-34a KO mice.

Conclusions

Our findings reveal that miR-34a deficiency augments skin wound inflammation response and leads to impaired wound healing, which suggest that targeted inhibition of miR-34a for tissue repair/regeneration should be with serious consideration.

The role of miR-34 in cancer drug resistance

Resistance to conventional chemotherapy remains a major cause of cancer relapse and cancer-related deaths. Therefore, there is an urgent need to overcome resistance barriers. To improve cancer treatment approaches, it is critical to elucidate the basic mechanisms underlying drug resistance. Increasingly, the mechanisms involving micro-RNAs (miRNAs) are studied because miRNAs are also considered practical therapeutic options due to high degrees of specificity, efficacy, and accuracy, as well as their ability to target multiple genes at the same time. Years of research have firmly established miR-34 as a key tumor suppressor miRNA whose target genes are involved in drug resistance mechanisms. Indeed, numerous articles show that low levels of circulating miR-34 or tumor-specific miR-34 expression are associated with poor response to chemotherapy. In addition, elevation of inherently low miR-34 levels in resistant cancer cells effectively restores sensitivity to chemotherapeutic agents. Here, we review this literature, also highlighting some contradictory observations. In addition, we discuss the potential utility of miR-34 expression as a predictive biomarker for chemotherapeutic drug response. Although caution needs to be exercised, miR-34 is emerging as a biomarker that could improve cancer precision medicine.

Epidrugs: targeting epigenetic marks in cancer treatment

Growing evidence suggests that aberrant epigenetic regulation of gene function is strongly related to the genesis of cancer. Unlike genetic mutations, the ability to reprogram the epigenetic landscape in the cancer epigenome is one of the most promising target therapies in both treatment and reversibility of drug resistance. Epigenetic alterations in cancer development and progression may be the basis for the individual variation in drug response. Thus, this review focuses on the emerging area of pharmaco(epi)genomics, specifically highlighting epigenetic reprogramming during tumorigenesis and how epigenetic markers are targeted as a therapy (epidrugs) and the clinical implications of this for cancer treatment.

MicroRNA-34a Acutely Regulates Synaptic Efficacy in the Adult Dentate Gyrus In Vivo

Activity-dependent synaptic plasticity involves rapid regulation of neuronal protein synthesis on a time-scale of minutes. miRNA function in synaptic plasticity and memory formation has been elucidated by stable experimental manipulation of miRNA expression and activity using transgenic approaches and viral vectors. However, the impact of rapid miRNA modulation on synaptic efficacy is unknown. Here, we examined the effect of acute (12 min), intrahippocampal infusion of a miR-34a antagonist (antimiR) on medial perforant path-evoked synaptic transmission in the dentate gyrus of adult anesthetised rats. AntimiR-34a infusion acutely depressed medial perforant path-evoked field excitatory post-synaptic potentials (fEPSPs). The fEPSP decrease was detected within 9 min of infusion, lasted for hours, and was associated with knockdown of antimiR-34a levels. AntimiR-34a-induced synaptic depression was sequence-specific; no changes were elicited by infusion of scrambled or mismatch control. The rapid modulation suggests that a target, or set of targets, is regulated by miR-34a. Western blot analysis of dentate gyrus lysates revealed enhanced expression of Arc, a known miR-34a target, and four novel predicted targets (Ctip2, PKI-1α, TCF4 and Ube2g1). Remarkably, antimiR-34a had no effect when infused during the maintenance phase of long-term potentiation. We conclude that miR-34a regulates basal synaptic efficacy in the adult dentate gyrus in vivo. To our knowledge, these in vivo findings are the first to demonstrate acute (< 9 min) regulation of synaptic efficacy in the adult brain by a miRNA.

Identification of miRNAs correlating with stage and progression of colorectal cancer

Aim: miRNAs control biological processes that are implicated in carcinogenesis, and have been researched as potential biomarkers for colorectal cancer (CRC). The aim of the current study was to evaluate the miRNA expression profile in CRC patients to determine their potential to be used as biomarkers in the disease. Materials & methods: Total 47 tissues and their matched marginal tissues, as control group, were obtained from CRC patients. The transcript levels of a selected panel of 15 cancer-associated miRNAs were quantified via real-time gene expression method. Results: miR-155, miR130a, miR-181b, miR-196a, miR-200c and miR-224 were significantly upregulated, while miR122, miR-132, miR-203b, miR330, miR-323, miR-378a-3p and miR-598 we significantly downregulated in CRC. Conclusion: We identified a panel of miRNAs that may be involved in the etiology and pathogenesis of CRC, and may be used for novel diagnostic and therapeutic strategies.

Assessment of anticancer activity of Pulicaria undulata on hepatocellular carcinoma HepG2 cell line

Searching for new sources of safe nutraceuticals antitumor drugs is an important issue. Consequentially, this study designed to assess the antitumor activity of Pulicaria undulata extract in vitro in the treatment of hepatocellular carcinoma HepG2 cell line. Aerial parts of P. undulata plants were collected, used for phytochemical analysis, and assessed for anticancer activity. The antitumor activity was evaluated through studying the cell viability and apoptotic pathway. The gas chromatography-mass spectrometry phytochemical analysis revealed that P. undulata is a promising new source of several known antioxidant and antitumor compounds which could participate in drug development and exploration of alternative strategies to the harmful synthetic antitumor drugs. P. undulata stifled HepG2 cell viability in a concentration-dependent manner. Meanwhile, P. undulata tempted substantial apoptosis in HepG2 cells and enhanced the expression of miR-34a. However, the mRNA expression level of antiapoptotic B-cell lymphoma-2 was markedly decreased by P. undulata treatment. Moreover, P. undulata increased the protein expression of proapoptotic p53 and caspase 3/9 with reducing B-cell lymphoma-2 protein expression level. Thus, P. undulata induced apoptosis in the HepG2 cells by overexpression of miR-34a which regulates p53/B-cell lymphoma-2/caspases signaling pathway. These findings were well appreciated with morphological studies of cells treated with P. undulata. In conclusion, P. undulata could be a probable candidate agent for the initiation of cell apoptosis in HepG2 and thereby can serve as promising therapeutic agent for treatment of hepatocellular carcinoma which should attract further studies.

Candidate Genes and MiRNAs Linked to the Inverse Relationship Between Cancer and Alzheimer's Disease: Insights From Data Mining and Enrichment Analysis

The incidence of cancer and Alzheimer’s disease (AD) increases exponentially with age. A growing body of epidemiological evidence and molecular investigations inspired the hypothesis of an inverse relationship between these two pathologies. It has been proposed that the two diseases might utilize the same proteins and pathways that are, however, modulated differently and sometimes in opposite directions. Investigation of the common processes underlying these diseases may enhance the understanding of their pathogenesis and may also guide novel therapeutic strategies. Starting from a text-mining approach, our in silico study integrated the dispersed biological evidence by combining data mining, gene set enrichment, and protein-protein interaction (PPI) analyses while searching for common biological hallmarks linked to AD and cancer. We retrieved 138 genes (ALZCAN gene set), computed a significant number of enriched gene ontology clusters, and identified four PPI modules. The investigation confirmed the relevance of autophagy, ubiquitin proteasome system, and cell death as common biological hallmarks shared by cancer and AD. Then, from a closer investigation of the PPI modules and of the miRNAs enrichment data, several genes (SQSTM1, UCHL1, STUB1, BECN1, CDKN2A, TP53, EGFR, GSK3B, and HSPA9) and miRNAs (miR-146a-5p, MiR-34a-5p, miR-21-5p, miR-9-5p, and miR-16-5p) emerged as promising candidates. The integrative approach uncovered novel miRNA-gene networks (e.g., miR-146 and miR-34 regulating p62 and Beclin1 in autophagy) that might give new insights into the complex regulatory mechanisms of gene expression in AD and cancer.

Introducing LNAzo: More Rigidity for Improved Photocontrol of Oligonucleotide Hybridization

Oligonucleotide-based therapeutics have made rapid progress in clinical treatment of a variety of disease indications. Since most therapeutic oligonucleotides serve more than just one function and tend to have a prolonged lifetime, spatio-temporal control of these functions would be desirable. Photoswitches like azobenzene have proven themselves as useful tools in this matter. Upon irradiation, the photoisomerization of the azobenzene moiety causes destabilization in adjacent base pairs, leading to a decreased hybridization affinity. Since the way the azobenzene is incorporated in the oligonucleotide is of utmost importance, we synthesized locked azobenzene C-nucleosides and compared their photocontrol capabilities to established azobenzene C-nucleosides in oligonucleotide test-sequences by means of fluorescence-, UV/Vis-, and CD-spectroscopy.

miR-34a promotes bone regeneration in irradiated bone defects by enhancing osteoblastic differentiation of mesenchymal stromal cells in rats

Background

Radiation exposure negatively affects the regenerative ability and makes reconstruction of bone defects after tumor section difficult. miR-34a is involved in radiation biology and bone metabolism. The aim of this study was to investigate whether miR-34a could contribute to bone regeneration in irradiated bone defects.

Methods

The expression of miR-34a was analyzed during the osteoblastic differentiation of irradiated BMSCs and bone formation in irradiated bone defects. miR-34a mimics and miR-34a inhibitor were used to upregulate or suppress the expression of miR-34a in BMSCs irradiated with 2 or 4 Gy X-ray radiation. In vitro osteogenesis and subcutaneous osteogenesis were used to assess the effects of miR-34a on the osteogenic ability of radiation-impaired BMSCs. Collagen-based hydrogel containing agomiR-34a or antagomiR-34a were placed into the 3-mm defects of irradiated rat tibias to test the effect of miR-34a on bone defect healing after irradiation.

Results

miR-34a was upregulated in the process of bone formation after irradiation. Transfecting radiation-impaired BMSCs with miR-34a mimics enhanced their osteoblastic differentiation in vitro by targeting NOTCH1. Overexpression of miR-34a enhanced the ectopic bone formation of irradiated BMSCs. In situ delivery of miR-34a promoted bone regeneration in irradiated bone defects.

Conclusions

miR-34a promoted the osteoblastic differentiation of BMSCs and enhanced the ectopic bone formation after irradiation. miR-34a promoted bone defect healing in irradiated rat tibias. miR-34a-targeted therapy might be a promising strategy for promoting the reconstruction of bone defects after radiotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1285-y) contains supplementary material, which is available to authorized users.

lncRNA KCNQ1OT1 enhances the chemoresistance of oxaliplatin in colon cancer by targeting the miR-34a/ATG4B pathway

Purpose

The chemoresistance of colon cancer to oxaliplatin (L-OHP) indicates poor prognosis. Long non-coding RNA (lncRNA) KCNQ1OT1 (KCNQ1 opposite strand/antisense transcript 1) has been shown to participate in the tumorigenesis of several types of cancers. However, little is known about the role of KCNQ1OT1 in the chemoresistance and prognosis of colon cancer.

Materials and methods

Quantitative-PCR and Western blot were used to measure the expression profiles of KCNQ1OT1, miR-34a, and Atg4B in colon cancer tissues and cells. Cell viability assay and flow cytometry were used to examine their effects on cell proliferation and death. Cleavage of LC3 and GFP-LC3 plasmid transfection were used to detect autophagic activity. Double luciferase reporter assay was used to verify the interactions between miRNA and lncRNA or mRNA. Xenograft tumor model was used to verify the effects of KCNQ1OT1 in vivo.

Results

In this study, it is shown that the expression level of KCNQ1OT1 was increased in tumor, which indicated poor prognosis in colon cancer patients. Using colon cancer cell lines HCT116 and SW480, it was demonstrated that knockdown of KCNQ1OT1 decreased the cell viability and increased the apoptosis rates upon L-OHP treatment. Further studies indicated that Atg4B upregulation was partially responsible for KCNQ1OT1-induced protective autophagy and chemoresistance. Moreover, miR-34a functioned as a bridge between KCNQ1OT1 and Atg4B, which could be sponged by KCNQ1OT1, while it could also bind to the 3'-UTR of Atg4B and downregulate its expressions. Finally, we show that the KCNQ1OT1/miR-34a/Atg4B axis regulated the chemoresistance of colon cancer cells in vitro and in vivo.

Conclusion

lncRNA KCNQ1OT1 promoted the chemoresistance of colon cancer by sponging miR-34a, thus upregulating the expressions of Atg4B and enhancing protective autophagy. KCNQ1OT1 might become a promising target for colon cancer therapeutics.

MicroRNA-34a-5p suppresses tumorigenesis and progression of glioma and potentiates Temozolomide-induced cytotoxicity for glioma cells by targeting HMGA2

Glioma is a frequently diagnosed brain tumors and Temozolomide (TMZ) is a common chemotherapeutic drug for glioma. High mobility group AT-hook 2 (HMGA2) was reported to be linked with glioma pathogenesis and Temozolomide (TMZ)-induced cytotoxicity. Our present study aimed to further search for the upstream regulatory microRNAs (miRNAs) of HMGA2 in glioma. RT-qPCR assay was conducted to measure the expression of HMGA2 mRNA and microRNA-34a-5p (miR-34a-5p). HMGA2 protein expression was examined by western blot assay. Cell proliferative ability and cell viability was assessed by CCK-8 assay. Cell migratory and invasive capacities were estimated by Transwell migration and invasion assay. Bioinformatics analysis and luciferase reporter assay was conducted to investigate the potential interaction between miR-34a-5p and HMGA2. Mouse xenograft experiments were performed to further test the roles of TMZ, miR-34a-5p and HMGA2, alone or in combination, in glioma tumorigenesis in vivo. We found HMGA2 expression was notably upregulated in glioma tissues and cells, and associated with glioma grade and poor prognosis. HMGA2 knockdown or miR-34a-5p overexpression inhibited migration, invasion, proliferation and enhanced TMZ-induced cytotoxicity in glioma cells. Moreover, HMGA2 was a target of miR-34a-5p. And, miR-34a-5p expression was remarkably reduced in glioma tissues and cells. MiR-34a-5p exerted its function through targeting HMGA2 in glioma cells. HMGA2 knockdown or miR-34a-5p overexpression inhibited tumor growth and enhanced TMZ-mediated anti-tumor effect in glioma xenograft models. We concluded MiR-34a-5p suppressed tumorigenesis and progression of glioma and potentiated TMZ-induced cytotoxicity for glioma cells by targeting HMGA2, deepening our understanding on molecular basis of HMGA2 in glioma.

Roles of MicroRNA-34a in Epithelial to Mesenchymal Transition, Competing Endogenous RNA Sponging and Its Therapeutic Potential

MicroRNA-34a (miR-34a), a tumor suppressor, has been reported to be dysregulated in various human cancers. MiR-34a is involves in certain epithelial-mesenchymal transition (EMT)-associated signal pathways to repress tumorigenesis, cancer progression, and metastasis. Due to the particularity of miR-34 family in tumor-associated EMT, the significance of miR-34a is being increasingly recognized. Competing endogenous RNA (ceRNA) is a novel concept involving mRNA, circular RNA, pseudogene transcript, and long noncoding RNA regulating each other’s expressions using microRNA response elements to compete for the binding of microRNAs. Studies showed that miR-34a is efficient for cancer therapy. Here, we provide an overview of the function of miR-34a in tumor-associated EMT. ceRNA hypothesis plays an important role in miR-34a regulation in EMT, cancer progression, and metastasis. Its potential roles and challenges as a microRNA therapeutic candidate are discussed. As the negative effect on cancer progression, miR-34a should play crucial roles in clinical diagnosis and cancer therapy.

Blockade of crizotinib-induced BCL2 elevation in ALK-positive anaplastic large cell lymphoma triggers autophagy associated with cell death

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphomas are tumors that carry translocations involving the ALK gene at the 2p23 locus, leading to the expression of ALK tyrosine kinase fusion oncoproteins. Amongst hematologic malignancies, these lymphomas are particular in that they express very low levels of B-cell lymphoma 2 (BCL2), a recognized inhibitor of apoptosis and autophagy, two processes that share complex interconnections. We have previously shown that treatment of ALK-positive anaplastic large cell lymphoma cells with the ALK tyrosine kinase inhibitor crizotinib induces autophagy as a pro-survival response. Here, we observed that crizotinib-mediated inactivation of ALK caused an increase in BCL2 levels that restrained the cytotoxic effects of the drug. BCL2 downregulation in combination with crizotinib treatment potentiated loss of cell viability through both an increase in autophagic flux and cell death, including apoptosis. More importantly, our data revealed that the blockade of autophagic flux completely reversed impaired cell viability, which demonstrates that excessive autophagy is associated with cell death. We propose that the downregulation of BCL2 protein, which plays a central role in the autophagic and apoptotic machinery, combined with crizotinib treatment may represent a promising therapeutic alternative to current ALK-positive anaplastic large cell lymphoma treatments.

Evaluation of pre-mir-34a rs72631823 single nucleotide polymorphism in triple negative breast cancer: A case-control study

Aim

The purpose of this study is to evaluate the role of pre-miR34a rs72631823 as potential risk factor and/or prognostic marker in patients with triple negative breast cancer.

Methods

114 samples of DNA from paraffin embedded breast normal tissues of patients with triple negative breast cancer and 124 samples of healthy controls were collected and analyzed for pre-miR34a rs72631823 polymorphism.

Results

Pre-miR34a rs72631823 A allele was associated with increased TNBC risk both in univariate and multivariate analysis. The number of pre-miR34a rs72631823 AA subjects was very small and the association did not reach significance (p = 0.176, Fisher’s exact test). The examined polymorphism was not associated with overall survival at the univariate or multivariate Cox regression analysis (adjusted HR = 1.60, 95%CI: 0.64–3.96 for miR34 rs72631823 GA/AA vs. GG).

Conclusion

Our case-control study suggests that pre-miR34a rs72631823 A allele is associated with increased triple negative breast cancer risk.

Interplay of non-coding RNAs and approved antimetabolites such as gemcitabine and pemetrexed in mesothelioma

Gemcitabine and pemetrexed are clinically approved antimetabolites for the therapy of mesothelioma diseases. These drugs are often applied in combination with platinum complexes and other drugs. The activity of antimetabolites depended on the expression levels of certain non-coding RNAs, in particular, of small microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). The development of tumor resistance towards antimetabolites was regulated by non-coding RNAs. An overview of the interplay between gemcitabine/pemetrexed antimetabolites and non-coding RNAs in mesothelioma is provided. Further to this, various non-coding RNA-modulating agents are discussed which displayed positive effects on gemcitabine or pemetrexed treatment of mesothelioma diseases. A detailed knowledge of the connections of non-coding RNAs with antimetabolites will be constructive for the design of improved therapies in future.

A comprehensive investigation using meta-analysis and bioinformatics on miR-34a-5p expression and its potential role in head and neck squamous cell carcinoma

HNSCC is the sixth most common cancer worldwide and is characterized as an aggressive, malignant tumor. MiR-34a-5p (miR-34a) expression has been strongly linked to HNSCC development. However, the exact target gene of miRNA-34a-as well as its biological and mechanistic pathways-are unclear. It is critical that the clinical value of HNSCC receive further study. We conducted a continuous variable, meta-analysis from data found in the cancer literature as well as that provided by the Cancer Genome Atlas (TCGA) to estimate miR-34a expression in HNSCC. Next, TCGA database, microarray, and MiRWalk were all used to predict the target gene of miR-34a in HNSCC. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to explore the underlying molecular mechanism of miR-34a in HNSCC. Finally, we used Spearman's analysis and survival curves to identify the roles of related target genes involved in significant pathways during the development of HNSCC. Expression levels of miR-34a in HNSCC were significant lower than those in normal tissues (P<0.05) and summary receiver operating characteristic (sROC) was 0.72. The collective results obtained from KEGG and GO indicated that miR-34a may be involved in the development of HNSCC via known cancer pathways, including the p53 and/or PI3K-Akt signalling pathways. Our results suggested miR-34a has potential use as a novel, non-invasive and highly sensitive biomarker for diagnostic in HNSCC. Finally, it likely plays an essential role in the deterioration and ultimate tumorigenesis of HNSCC through determined cancer pathways.

MicroRNAs as Potential Biomarkers in Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive type of skin cancer associated with a poor prognosis. This carcinoma was named after its presumed cell of origin, the Merkel cell, which is a mechanoreceptor cell located in the basal epidermal layer of the skin. Merkel cell polyomavirus seems to be the major causal factor for MCC because approximately 80% of all MCCs are positive for viral DNAs. UV exposure is the predominant etiological factor for virus-negative MCCs. Intracellular microRNA analysis between virus-positive and virus-negative MCC cell lines and tumor samples have identified differentially expressed microRNAs. Comparative microRNA profiling has also been performed between MCCs and other non-MCC tumors, but not between normal Merkel cells and malignant Merkel cells. Finally, Merkel cell polyomavirus encodes one microRNA, but its expression in virus-positive MCCs is low, or non-detectable or absent, jeopardizing its biological relevance in tumorigenesis. Here, we review the results of microRNA studies in MCCs and discuss the potential application of microRNAs as biomarkers for the diagnosis, progression and prognosis, and treatment of MCC.

Downregulation of miR-34a promotes endothelial cell growth and suppresses apoptosis in atherosclerosis by regulating Bcl-2

Several miRNAs have been demonstrated to be involved in endothelial dysfunction during atherosclerosis (AS). However, the detailed roles and underlying mechanisms of miR-34a in AS-associated endothelial cell apoptosis are far from being addressed. Apolipoprotein E-deficient (ApoE^-/-) mice fed with high-fat diet (HFD) were used as in vivo model of AS. Oxidized low-density lipoprotein (ox-LDL)-treated human aortic endothelial cells (HAECs) were applied as in vitro model of AS. The effects of miR-34a on atherosclerotic lesions were evaluated by hematoxylin-eosin (HE) and Oil Red O staining. Pecam-1⁺ endothelial cells were isolated from the aortic arch with flow cytometry. qRT-PCR and western blot were employed to measure gene and protein expression. The effects of miR-34a on cell viability, cell cycle distribution, and apoptosis were assessed by Cell counting kit (CCK)-8 and flow cytometry analysis. The relationship between miR-34a and Bcl-2 was confirmed by online softwares, luciferase reporter assay, and RNA immunoprecipitation (RIP). miR-34a was upregulated in HFD-induced ApoE^-/- mice and ox-LDL-treated HAECs. Anti-miR-34a decreased atherosclerotic lesions and inhibited Pecam-1⁺ endothelial cells apoptosis in HFD-induced ApoE^-/- mice. Moreover, anti-miR-34a significantly promoted cell viability, alleviated cell cycle arrest, and restrained apoptosis in ox-LDL-treated HAECs. Furthermore, Bcl-2 was identified as a target of miR-34a, and miR-34a inhibited Bcl-2 expression via binding to its 3'UTR. Rescue experiments demonstrated that Bcl-2 overexpression dramatically reversed miR-34a-mediated inhibition of cell growth and promotion of apoptosis in ox-LDL-exposed HAECs. Depletion of miR-34a facilitated endothelial cell growth and blocked apoptosis in AS by upregulating Bcl-2, offering a promising avenue for AS therapy.