Histone Deacetylase 4 Promotes Osteosarcoma Cell Proliferation and Invasion by Regulating Expression of Proliferating Cell Nuclear Antigen

Interactions between circRNAs and miR-141 in Cancer: From Pathogenesis to Diagnosis and Therapy

The function of non-coding RNAs (ncRNAs) in the pathogenesis and development of cancer is indisputable. Molecular mechanisms underlying carcinogenesis involve the aberrant expression of ncRNAs, including circular RNAs (circRNAs), and microRNAs (miRNAs). CircRNAs are a class of single-stranded, covalently closed RNAs responsible for maintaining cellular homeostasis through their diverse functions. As a part of the competing endogenous RNA (ceRNAs) network, they play a central role in the regulation of accessibility of miRNAs to their mRNA targets. The interplay between these molecular players is based on the primary role of circRNAs that act as miRNAs sponges, and the circRNA/miRNA imbalance plays a central role in different pathologies including cancer. Herein, we present the latest state of knowledge about interactions between circRNAs and miR-141, a well-known member of the miR-200 family, in malignant transformation, with emphasis on the biological role of circRNA/miR-141/mRNA networks as a future target for novel anti-cancer therapies.

Synergistic Interaction of the Class IIa HDAC Inhibitor CHDI0039 with Bortezomib in Head and Neck Cancer Cells

In contrast to class I/IIb/pan histone deacetylase inhibitors (HDACi), the role of class IIa HDACi as anti-cancer chemosensitizing agents is less well understood. Here, we studied the effects of HDAC4 in particular and the class IIa HDACi CHDI0039 on proliferation and chemosensitivity in Cal27 and cisplatin-resistant Cal27CisR head and neck squamous cell cancer (HNSCC). HDAC4 and HDAC5 overexpression clones were generated. HDAC4 overexpression (Cal27_HDAC4) increased proliferation significantly compared to vector control cells (Cal27_VC). Chicken chorioallantoic membrane (CAM) studies confirmed the in vitro results: Cal27_HDAC4 tumors were slightly larger than tumors from Cal27_VC, and treatment with CHDI0039 resulted in a significant decrease in tumor size and weight of Cal27_HDAC4 but not Cal27_VC. Unlike class I/pan-HDACi, treatment with CHDI0039 had only a marginal impact on cisplatin cytotoxicity irrespective of HDAC4 and HDAC5 expression. In contrast, the combination of CHDI0039 with bortezomib was synergistic (Chou–Talalay) in MTT and caspase 3/7 activation experiments. RNAseq indicated that treatment with CHDI0039 alters the expression of genes whose up- or downregulation is associated with increased survival in HNSCC patients according to Kaplan–Meier data. We conclude that the combination of class IIa HDACi with proteasome inhibitors constitutes an effective treatment option for HNSCC, particularly for platinum-resistant cancers.

HDAC4 in cancer: A multitasking platform to drive not only epigenetic modifications

Controlling access to genomic information and maintaining its stability are key aspects of cell life. Histone acetylation is a reversible epigenetic modification that allows access to DNA and the assembly of protein complexes that regulate mainly transcription but also other activities. Enzymes known as histone deacetylases (HDACs) are involved in the removal of the acetyl-group or in some cases of small hydrophobic moieties from histones but also from the non-histone substrate. The main achievement of HDACs on histones is to repress transcription and promote the formation of more compact chromatin. There are 18 different HDACs encoded in the human genome. Here we will discuss HDAC4, a member of the class IIa family, and its possible contribution to cancer development.

Andrographolide inhibits the growth of human osteosarcoma cells by suppressing Wnt/β-catenin, PI3K/AKT and NF-κB signaling pathways

Osteosarcoma (OS) is an aggressive malignant skeletal tumor characterized by an extremely poor prognosis and a high tendency to recur. The frequently used anti-OS chemotherapy regents are often limited by drug resistance and severe adverse events. It is urgent to develop more effective, tolerable and safe drugs for the treatment of OS. Andrographolide (AG), a diterpenoid lactone isolated from Andrographis paniculata, has been proved to possess anti-tumor activity against several human cancer types. In this current study, we evaluated the inhibitory effect of AG on human OS cells and probed the possible mechanism. We found that AG inhibited the proliferation of human OS cells and blocked cell cycle at G2/M phase. Furthermore, AG impeded the migration and invasion, while promoted the apoptosis of human OS cells. Moreover, we found that AG inhibited OS growth and lung metastasis in orthotopic transplantation model. Mechanistically, we demonstrated that AG suppressed the activity of Wnt/β-catenin, PI3K/AKT and NF-κB signaling pathways. Notably, we validated that AG synergized with the inhibitors of Wnt/β-catenin, PI3K/AKT and NF-κB to suppress the proliferation, migration and invasion of human OS cells. Collectively, our study conclusively demonstrates that AG inhibits the growth of human OS cells, thus, may be a promising candidate for the treatment of OS.

Hdac4 Regulates the Proliferation of Neural Crest-Derived Osteoblasts During Murine Craniofacial Development

Craniofacial development involves the regulation of a compendium of transcription factors, signaling molecules, and epigenetic regulators. Histone deacetylases (HDACs) are involved in the regulation of cell proliferation, differentiation, and homeostasis across a wide range of tissues, including the brain and the cardiovascular, muscular, and skeletal systems. However, the functional role of Hdac4 during craniofacial development remains unclear. In this study, we investigated the effects of knocking out Hdac4 on craniofacial skeletal development by conditionally disrupting the Hdac4 gene in cranial neural crest cells (CNCCs) using Cre-mediated recombination. Mice deficient for Hdac4 in CNCC-derived osteoblasts demonstrated a dramatic decrease in frontal bone formation. In vitro, pre-osteoblasts (MC3T3-E1 cells) lacking Hdac4 exhibited reduced proliferative activity in association with the dysregulation of cell cycle-related genes. These findings suggested that Hdac4 acts, at least in part, as a regulator of craniofacial skeletal development by positively regulating the proliferation of CNCC-derived osteoblasts.

circ‑LRP6 contributes to osteosarcoma progression by regulating the miR‑141‑3p/HDAC4/HMGB1 axis

Circular RNA-lipoprotein receptor 6 (circ-LRP6) serves a role in promoting the tumorigenesis of retinoblastoma, esophageal squamous cell cancer and oral squamous cell carcinoma; however, whether circ-LRP6 demonstrates the same effect in osteosarcoma (OS) is yet to be fully elucidated. The present study aimed to analyze the expression, role and potential molecular mechanism of circ-LRP6 in OS. The expression levels of circ-LRP6, microRNA (miR)-141-3p, histone deacetylase 4 (HDAC4) and high mobility group protein 1 (HMGB1) were evaluated by reverse transcription- quantitative PCR in OS tissues and cell lines. Cell Counting Kit-8, Transwell and Matrigel assays were conducted to evaluate cell proliferation, migration and invasion, respectively. Western blotting was also performed to determine HDAC4 and HMGB1 protein expression levels. Bioinformatics and dual-luciferase reporter assays were used to predict and analyze the interactions between circ-LRP6 and miR-141-3p, miR-141-3p and HDAC4, as well as between miR-141-3p and HMGB1. Additionally, RNA immunoprecipitation was performed to verify the association between circ-LRP6 and miR-141-3p. The results confirmed that circ-LRP6 was highly expressed in OS tissues and cell lines. In addition, circ-LRP6 negatively regulated the expression of miR-141-3p and, in turn, miR-141-3p negatively regulated HDAC4 and HMGB1 expression. Functional assays revealed that circ-LRP6 knockdown inhibited the proliferation, migration and invasion of OS cells, whereas the inhibition of miR-141-3p or the overexpression of either HDAC4 or HMGB1 partly reversed the inhibitory effect of circ-LRP6 knockdown. In summary, the present study determined that circ-LRP6 knockdown inhibited the proliferation, migration and invasion of OS cells by regulating the miR-141-3p/HDAC4/HMGB1 axis.

HDAC4 Mediates Smoking-Induced Pancreatic Cancer Metastasis

OBJECTIVE

Cigarette smoking is an established risk factor for pancreatic ductal adenocarcinoma (PDAC). In this project, we investigated the effect of smoking and the role of histone deacetylase 4 (HDAC4) in PDAC invasion and metastasis.

METHODS

Cells were treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and cigarette smoke extract and the mRNA levels of HDACs were measured by real-time polymerase chain reaction. Invasion was measured using the Matrigel Invasion Assay. Syngeneic PDAC mice were treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and metastasis measured. Human PDAC primary and metastatic tissues were analyzed by immunohistochemistry.

RESULTS

Levels of HDAC4 mRNA were increased by smoking. Smoking compounds significantly promoted invasion of cancer cells and promoted metastasis of PDAC cells to different organs, including the liver and the lung, whereas inhibition of HDAC4 prevented this effect. The effect of HDAC4 inhibition on preventing smoking-induced metastasis was greater in the liver compared with the lung. We found that HDAC4 is highly expressed in primary and metastatic PDAC tumors.

CONCLUSIONS

We found that HDAC4 is the only HDAC induced by smoking among all HDACs analyzed. We found that smoking promotes invasion and metastasis of PDAC cells through a mechanism that involves HDAC4 and that HDAC4 is a promising target for preventing PDAC metastasis.

The Multiple Function of lncRNA MALAT1 in Cancer Occurrence and Progression

Long non-coding RNAs (lncRNAs) have received particular attention in the last decade due to its engaging in carcinogenesis and tumorigenesis. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a lncRNA that plays physiological and pathological roles in many aspects of genome function as well as biological processes involved in cell development, differentiation, proliferation, invasion, and migration. In this article, we will review the effects of lncRNA MALAT1 on the progression of six prevalent human cancers by focusing on MALAT1 ability to regulate post-transcriptional modification and signaling pathways.

Predictive Study of the Active Ingredients and Potential Targets of Codonopsis pilosula for the Treatment of Osteosarcoma via Network Pharmacology

Osteosarcoma (OS) is the most common type of primary bone tumor in children and adults. Dangshen (Codonopsis pilosula) is a traditional Chinese medicine commonly used in the treatment of OS worldwide. However, the molecular mechanisms of Dangshen in OS remain unclear. Hence, in this study, we aimed to systematically explore the underlying mechanisms of Dangshen in the treatment of OS. Our study adopted a network pharmacology approach, focusing on the identification of active ingredients, drug target prediction, gene collection, gene ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and other network tools. The network analysis identified 15 active compounds in Dangshen that were linked to 48 possible therapeutic targets related to OS. The results of the gene enrichment analysis show that Dangshen produces a therapeutic effect in OS likely by regulating multiple pathways associated with DNA damage, cell proliferation, apoptosis, invasion, and migration. Based on the network pharmacology approach, we successfully predicted the active compounds and their respective targets. In addition, we illustrated the molecular mechanisms that mediate the therapeutic effect of Dangshen in OS. These findings may aid in the development of novel targeted therapies for OS in the future.

DNA damage response and repair in osteosarcoma: Defects, regulation and therapeutic implications

Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents which has the survival rate of 20% in its advanced stages. Osteosarcomas are mostly resistance to our common treatments. DNA damage response (DDR) is a specialized multistep process containing abundant proteins which are necessary for the survival of any cell and organism. DDR machinery detects a diversity of DNA lesions and inhibits the cell cycle progression if these lesions are not repairable. DDR is involved in aging, age-related diseases, and cancer. In recent years, DDR inhibitors have gained the attention of researches due to their potentials in offering novel therapeutic targets and improving the response of many cancers to either chemo- or radio-therapy. In this regard, we tried to gather a great body of evidence about the role of DDR ingredients in osteosarcoma's initiation/progression, prognosis, and treatment.

RETRACTED: MicroRNA-29a-3p strengthens the effect of dexmedetomidine on improving neurologic damage in newborn rats with hypoxic-ischemic brain damage by inhibiting HDAC4

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figs. 2B+E, which appear to have the same eyebrow shaped phenotype as many other publications tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0). The journal requested the corresponding author comment on these concerns and provide the raw data. However, the authors were not responsive to the request for comment. Since original data could not be provided, the overall validity of the results could not be confirmed. Therefore, the Editor-in-Chief decided to retract the article.

Knockdown of CircCRIM1 Inhibits HDAC4 to Impede Osteosarcoma Proliferation, Migration, and Invasion and Facilitate Autophagy by Targeting miR-432-5p

BACKGROUND

Circular RNAs (circRNAs) serve for a genre of considerable modulatory molecules that have been largely researched in human cancers. However, the contribution of circRNA cysteine-rich transmembrane bone morphogenetic protein regulator 1 (circCRIM1) to osteosarcoma (OS) is completely unclear.

METHODS

All the RNA levels were examined via quantitative real-time polymerase chain reaction (qRT-PCR). Cellular proliferation and migration/invasion were, respectively, analyzed using 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay and transwell assay. The determination of all protein expression was administrated by Western blot. Dual-luciferase reporter assay was used for proving the target combination. The exploration of circCRIM1 in vivo was performed by xenograft assay.

RESULTS

In OS tissues and cells, circCRIM1 was differentially up-regulated. Functionally, cell proliferation, migration and invasion were suppressed while autophagy was promoted after circCRIM1 was down-regulated in OS cells. Mechanistically, mircoRNA-432-5p (miR-432-5p) was a miRNA target of circCRIM1 and the inhibitory effect of circCRIM1 knockdown on OS progression was achieved by targeting miR-432-5p. Moreover, histone deacetylase 4 (HDAC4) was a downstream gene of miR-432-5p and circCRIM1 targeted miR-432-5p to up-regulate HDAC4 level. MiR-432-5p inhibited proliferation, migration, and invasion but enhanced autophagy of OS cells through down-regulating HDAC4. In vivo, knockdown of circCRIM1 decreased OS growth via acting on the miR-432-5p/HDAC4 axis.

CONCLUSION

Our findings elucidated the oncogenic function of circCRIM1 in OS via the regulation of the miR-432-5p/HDAC4 axis, affording a novel view about how circRNA participated in OS development.

Protective role of histone deacetylase 4 from ultraviolet radiation-induced DNA lesions

Ultraviolet B (UVB) exposure is a core factor that leads to skin disease or carcinogenesis through the insufficient repair of DNA lesions. UVB-induced DNA lesions are mainly removed by the nucleotide excision repair (NER) mechanism. The expression of histone deacetylase 4 (HDAC4) is altered in the skin upon UVB exposure, indicating its possible implication in UVB-induced DNA lesions repair. Here, we investigated the role of HDAC4 in the NER removal of the main classes of UVB-induced DNA lesions consisting of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs). We found that UVB irradiation increased HDAC4 expression at both the mRNA and protein levels. HDAC4 interacted with NER factor XPC, which played an important role in effectively removing the UVB-induced DNA lesions. This study provides an understanding of the HDAC4 function in DNA repair, which will allow the development of efficient strategies to protect the skin from UVR-induced diseases.