miR‐483‐3p suppresses the proliferation and progression of human triple negative breast cancer cells by targeting the HDAC8 >oncogene

MicroRNA-mediated epigenetic regulation of HDAC8 and HDAC6: Functional significance in cervical cancer

Cervical cancer, a leading global cause of female mortality, exhibits diverse molecular aberrations influencing gene expression and signaling pathways. Epigenetic factors, including histone deacetylases (HDACs) such as HDAC8 and HDAC6, along with microRNAs (miRNAs), play pivotal roles in cervical cancer progression. Recent investigations have unveiled miRNAs as potential regulators of HDACs, offering a promising therapeutic avenue. This study employed in-silico miRNA prediction, qRT-PCR co-expression studies, and Dual-Luciferase reporter assays to identify miRNAs governing HDAC8 and HDAC6 in HeLa, cervical cancer cells. Results pinpointed miR-497-3p and miR-324-3p as novel negative regulators of HDAC8 and HDAC6, respectively. Functional assays demonstrated that miR-497-3p overexpression in HeLa cells suppressed HDAC8, leading to increased acetylation of downstream targets p53 and α-tubulin. Similarly, miR-324-3p overexpression inhibited HDAC6 mRNA and protein expression, enhancing acetylation of Hsp90 and α-tubulin. Notably, inhibiting HDAC8 via miRNA overexpression correlated with reduced cell viability, diminished epithelial-to-mesenchymal transition (EMT), and increased microtubule bundle formation in HeLa cells. In conclusion, miR-497-3p and miR-324-3p emerge as novel negative regulators of HDAC8 and HDAC6, respectively, with potential therapeutic implications. Elevated expression of these miRNAs in cervical cancer cells holds promise for inhibiting metastasis, offering a targeted approach for intervention in cervical malignancy.

Long non-coding RNA small nucleolar RNA host gene 29 drives chronic myeloid leukemia progression via microRNA-483-3p/Casitas B-lineage Lymphoma axis-mediated activation of the phosphoinositide 3-kinase/Akt pathway

The aberrant expression of the long non-coding RNA (lncRNA) Small Nucleolar RNA Host Gene 29 (SNHG29) has been associated with various human cancers. However, the role of SNHG29 in chronic myeloid leukemia (CML) remains elusive. Therefore, this study aimed to investigate the function of SNHG29 in CML and unveil its potential underlying mechanisms. Herein, peripheral blood samples from 44 CML patients and 17 healthy subjects were collected. The expressions of SNHG29, microRNA-483-3p (miR-483-3p), and Casitas B-lineage Lymphoma (CBL) were measured using quantitative polymerase chain reaction (qPCR) or Western Blot. Cell viability, apoptosis, and cell cycle progression were evaluated using the Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine incorporation, and flow cytometry, respectively. Western Blot analysis was employed to assess protein expressions related to cellular proliferation, apoptosis, and oncogenesis. RNA immunoprecipitation and dual-luciferase reporter assays were utilized to verify the interactions among SNHG29, miR-483-3p, and CBL. SNHG29 was significantly overexpressed in both blood samples of CML patients and CML cell lines. In CML, increased expression of SNHG29 was positively correlated with clinical staging, and patients with high SNHG29 expression had poorer survival outcomes. Functionally, knocking down SNHG29 effectively inhibited CML cell proliferation and promoted apoptosis. Mechanistically, SNHG29 acted as a competing endogenous RNA for miR-483-3p to modulate CBL expression, thereby activating the Phosphoinositide 3-Kinase/Akt signaling pathway and mediating CML progression. In summary, these findings reveal that SNHG29 promotes tumorigenesis in CML, offering a potential therapeutic strategy for CML treatment.

Specific expression profile of follicular fluid-derived exosomal microRNAs in patients with diminished ovarian reserve

BACKGROUND

Diminished ovarian reserve (DOR) is defined as a reduction in ovarian reserve and oocyte quality. The pathophysiology of DOR has not been completely explained as of yet. Scholars have uncovered a large number of exosomes that have been detected in follicular fluid, and exosomal miRNAs have been proven to play a critical role in controlling ovarian disorders and follicle formation. We focused on the expression profile of follicular fluid-derived exosomal microRNAs (miRNAs) and attempted to understand if their role is connected to the pathomechanism of DOR.

METHODS

The follicular fluid-derived differentially expressed exosomal miRNAs (DEmiRs) between patients with DOR and those with normal ovarian function were investigated using the next-generation sequencing (NGS) method. The main metabolic and signaling pathways of DEmiRs were identified using the KEGG pathway database, disease ontology (DO) analysis, and gene ontology (GO) analysis. In the end, a Protein-Protein Interaction (PPI) network was built to search for exosomal miRNAs and their target genes that were potentially strongly connected with DOR.

RESULTS

In comparison to normal controls, 52 DEmiRs were discovered in follicular fluid-derived exosomes of DOR patients, of which 19 were up-regulated and 33 were down-regulated (|log2(fold change) |>2, P < 0.05). GO, DO analysis, and the KEGG pathway database revealed that many of these DEmiRs have broad biological roles that are connected to ovarian function and disorders. The top ten DEmiRs in terms of expression were then chosen for miRNA-mRNA interaction analysis. Totally, 8 experimentally supported miRNAs (hsa-miR-1246, hsa-miR-483-3p, hsa-miR-122-5p, hsa-miR-130b-3p, hsa-miR-342-3p, hsa-miR-625-3p, hsa-miR-675-3p, and hsa-miR-134-5p) and 126 target genes were filtrated by utilizing Cytoscape software. The module analysis findings of the PPI network showed that the main module cluster with a score > 6.0 (MCODE score = 15) had six hub genes, including IGFR, VEGFA, KRAS, ERBB2, RHOA, and PTEN (MCODE score = 11.472).

CONCLUSION

Our data suggested a special expression profile of follicular fluid-derived exosomal miRNAs in patients with DOR, which was probably correlated to ovarian dysfunction and follicle formation. These results may give a unique insight into a better understanding of the molecular process in the pathogenesis of DOR or other ovarian diseases.

HDAC8 as an emerging target in drug discovery with special emphasis on medicinal chemistry

HDAC8 catalyzes the deacetylation of both histones and nonhistone proteins. The abnormal expression of HDAC8 is associated with various pathological conditions causing cancer and other diseases like myopathies, Cornelia de Lange syndrome, renal fibrosis, and viral and parasitic infections. The substrates of HDAC8 are involved in diverse molecular mechanisms of cancer such as cell proliferation, invasion, metastasis and drug resistance. Based on the crystal structures and the key residues at the active site, HDAC8 inhibitors have been designed along the canonical pharmacophore. This article details the importance, recent advancements, and the structural and functional aspects of HDAC8 with special emphasis on the medicinal chemistry aspect of HDAC8 inhibitors that will help in developing novel epigenetic therapeutics.

Structure-Based Discovery of Selective Histone Deacetylase 8 Degraders with Potent Anticancer Activity

Inducing protein degradation by proteolysis targeting chimeras has gained tremendous momentum as a promising novel therapeutic strategy. Here, we report the design, synthesis, and biological characterization of highly potent proteolysis targeting chimeric small molecules targeting the epigenetic regulator histone deacetylase 8 (HDAC8). We developed potent and effective HDAC8 degraders, as exemplified by SZUH280 (16e), which effectively induced HDAC8 protein degradation and inhibited cancer cell growth even at low micromolar concentrations. Our preliminary mechanistic studies revealed that SZUH280 hampers DNA damage repair in cancer cells, promoting cellular radiosensitization. In mice, a single SZUH280 dose induced rapid and prolonged HDAC8 protein degradation in xenograft tumor tissues. Moreover, SZUH280 alone or in combination with irradiation resulted in long-lasting tumor regression in an A549 tumor mouse model. Our findings qualify a new chemical tool for HDAC8 knockdown and may lead to the development of a new class of cancer therapeutics.

Circ_0008784 activates Wnt/β-catenin pathway to affect the proliferation and apoptosis of triple-negative breast cancer cells

Triple-negative breast cancer (TNBC), as a subtype of breast tumors with aggressive nature, threatens the health of females across the globe. It's urgent to explore novel therapeutic targets for the improvement of TNBC treatments. Bioinformatics was used to identify circular RNA (circRNA) differentially expressed in TNBC tissues. The circular structure and expression in TNBC cells was subjected to analysis of quantitative polymerase chain reaction (qPCR) and PCR-agarose gel electrophoresis. Functional experiments and qPCR assays were carried out to probe the biological functions of circ_0008784 and microRNA-506-3p (miR-506-3p). It was verified by the assays that circ_0008784 propels proliferation and inhibit apoptosis of TNBC cells; and miR-506-3p was found to suppress proliferation and facilitate apoptosis of TNBC cells. TOP/FOP-Flash reporter, luciferase reporter, RNA-binding protein immunoprecipitation (RIP), RNA pulldown and rescue assays were implemented for exploring the underlying mechanisms of circ_0008784. It was found that circ_0008784 regulates Wnt/β-catenin signaling pathway, and augments TNBC cell progression via sponging miR-506-3p to modulate catenin beta 1 (CTNNB1). Circ_0008784 activates Wnt/β-catenin pathway to affect the proliferation and apoptosis of TNBC cells. Elucidating the mechanism of circ_0008784 underlying TNBC is of great significance to TNBC treatment.

miR-589-5p Inhibits Cell Proliferation by Targeting Histone Deacetylase 3 in Triple Negative Breast Cancer

BACKGROUND

Histone deacetylase 3 (HDAC3) is a potential oncogene that is significantly up-regulated in patients with breast cancer. MicroRNAs (miRs) are a group of small non-coding and regulatory RNAs which have recently been proposed as promising molecules for breast cancer target therapy. In the current study, we investigated the impact of miR-589-5p/ HDAC3 axis on cancer cell development in triple negative breast cancer (TNBC) cells.

METHODS

In-silico analysis determined that miR-589-5p potentially targets HDAC3. We evaluated the HDAC3 and mir-589-5p expression levels in clinical samples and breast cancer cell lines including MDA-MB-231, MDA-MB-468, MCF-7 and MCF-10A. HDAC3 was knocked out to investigate its role on cancer cell progression. Anti-cancerous role of the miR-589-5p was assessed using an expression vector. We evaluated possible alteration in the cell cycle progression, cell viability and cell proliferation, after transient transfection.

RESULTS

HDAC3 was over-expressed in TNBC clinical samples and breast cancer cell lines compared to non-cancerous controls while miR-589-5p was down regulated in cancer cells. Suppression of HDAC3 decreased the cell viability, cell proliferation and colony formation. Similar results were observed after over-expression of the miR-589-5p. Dual-Luciferase reporter assay confirmed the direct targeting of HDAC3 by miR-589-5p.

CONCLUSION

Our results showed that miR-589-5p mediates its anti-proliferative effects on breast cancer cells via targeting HDAC3. These findings suggest that the miR-589-5p/ HDAC3 axis could be considered as a possible therapeutic strategy in TNBC.

The role of histone deacetylase 3 in breast cancer

It has been recently revealed that Histone Deacetylase (HDAC) 3, a unique member of the HDACs family, can trigger and progress cancers by alternation in genes expression and proteins activity. Epigenetic modifications by HDACs have been studied well in various cancer cells. Recent studies have focused on the HDAC enzymes as a possible target in cancer therapy. There are significant documents on upregulation of HDAC3 in breast cancer (BC) cells which suggest an oncogenic role for this enzyme. Interestingly, some studies showed that HDAC3 inhibition could be considered as a promising target in breast cancer therapy, and thus far, several inhibitors from different nature have been introduced. In this review, we discussed the function and highlight the existing inhibitors of HDAC3 in BC pathogenesis and therapy.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.

LINC00662 Promotes Proliferation and Invasion and Inhibits Apoptosis of Glioma Cells Through miR-483-3p/SOX3 Axis

LINC00662 plays a prominent role in the carcinogenesis and progression of diverse cancers. However, its biological functions in glioma are still unclear. LINC00662 expression in glioma tissue samples and cell lines was examined by quantitative real-time polymerase chain reaction. The correlation between LINC00662 expression and the clinical characteristics of 50 patients with glioma was analyzed. LINC00662 knockdown and overexpression cell lines were constructed, and the effects of LINC00662 on the proliferation, invasion, and apoptosis of glioma cells were evaluated by cell counting kit-8, 5-ethynyl-2'-deoxyuridine, Transwell, and flow cytometry assays, respectively. Besides, the relationships among LINC00662, miR-483-3p, and sex-determining region Y-box 3 (SOX3) were assessed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Western blot was used to detect the regulatory effects of LINC00662 and miR-483-3p on SOX3 expression in glioma cells. LINC00662 expression level was elevated in glioma tissues and cell lines compared to that in normal tissues and cell lines. LINC00662 high expression was associated with the adverse prognosis of patients with glioma. Knockdown of LINC00662 repressed the proliferation and invasion of glioma cells, and promoted apoptosis. Additionally, it was revealed that LINC00662 acted as the molecular sponge of miR-483-3p, and SOX3 was verified as a direct target of miR-483-3p. The inhibition of miR-483-3p expression and SOX3 overexpression reversed the biological effects of LINC00662 knockdown on glioma cells. This study reports the key regulatory role of LINC00662/miR-483-3p/SOX3 axis in the tumorigenesis and progression of glioma, bringing novel insights into the underlying mechanisms of glioma.

The functional significance and cross-talk of non-coding RNAs in triple negative and quadruple negative breast cancer

One of the leading causes of cancer-related deaths worldwide is breast cancer, among which triple-negative breast cancer (TNBC) is the most malignant and lethal subtype. This cancer accounts for 10-20% of all breast cancer deaths. Proliferation, tumorigenesis, and prognosis of TNBC are affected when the androgen receptor (AR) is not expressed, and it is classified as quadruple negative breast cancer (QNBC). Non-coding RNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play a significant role in tumorigenesis by virtue of their oncogenic and tumor-suppressive properties. To regulate tumorigenesis, miRNAs interact with their target mRNAs and modulate their expression, whereas lncRNAs can either act alone or interact with miRNAs or other molecules through various signaling pathways. Conversely, circRNAs regulate tumorigenesis by acting as miRNA sponges predominantly. Recently, non-coding RNAs were studied comprehensively for their roles in tumor proliferation, progression, and metastasis. As a result of existing studies and research progress, non-coding RNAs have been implicated in TNBC, necessitating their use as biomarkers for future diagnostic applications. In this review, the non-coding RNAs are explicitly implicated in the regulation of breast cancer, and their cross-talk between TNBC and QNBC is also discussed.

Circulating exosomal microRNAs as diagnostic and prognostic biomarkers in patients with diffuse large B-cell lymphoma

Exosomal microRNAs (miRNAs) are potential biomarkers for a variety of tumors, but have not yet been studied in diffuse large B-cell lymphoma (DLBCL). Here, we investigated the use of exosomal miRNAs in DLBCL diagnosis and prognosis. A total of 256 individuals, including 133 DLBCL patients, 94 healthy controls (HCs), and 29 non-DLBCL concurrent controls (CCs), were enrolled. Exosomal miRNAs were profiled in the screening stage using microarray analysis, and miRNA candidates were confirmed in training, testing, and external testing stages using qRT-PCR. Follow-up information on the DLBCL patients was collected, and miRNAs were used to develop diagnostic and prognostic models for these patients. Five exosomal miRNAs (miR-379-5p, miR-135a-3p, miR-4476, miR-483-3p, and miR-451a) were differentially expressed between DLBCL patients and HCs with areas under the receiver operating characteristic curve (AUC) of 0.86, 0.90, and 0.86 for the training, testing, and external testing stages, respectively. Four exosomal miRNAs (miR-379-5p, miR-135a-3p, miR-4476, and miR-451a) were differentially expressed between patients with DLBCL and CCs, with an AUC of 0.78. One miRNA (miR-451a) was significantly associated with both progression-free survival (PFS) and overall survival (OS) of DLBCL patients, R analysis indicated the combination of miR-451a with international prognostic index was a better predictor of PFS and OS for these patients. Our study suggests that subsets of circulating exosomal miRNAs can be useful noninvasive biomarkers for the diagnosis of DLBCL and that the use of circulating exosomal miRNAs improves the identification of patients with newly diagnosed DLBCL with poor outcomes.

Imatinib Regulates miR-483-3p and Mitochondrial Respiratory Complexes in Gastrointestinal Stromal Tumors

Metabolic adaptation to increased oxidative phosphorylation (OXPHOS) has been found in gastrointestinal stromal tumor (GIST) upon imatinib treatment. However, the underlying mechanism of imatinib-induced OXPHOS is unknown. Discovering molecules that mediate imatinib-induced OXPHOS may lead to the development of therapeutic strategies synergizing the efficacy of imatinib. In this study, we explored the role of microRNAs in regulating OXPHOS in GIST upon imatinib treatment. Using a microarray approach, we found that miR-483-3p was one of the most downregulated miRNAs in imatinib-treated tumors compared to untreated tumors. Using an extended series of GIST samples, we further validated the downregulation of miR-483-3p in imatinib-treated GIST samples by RT-qPCR. Using both gain- and loss-of-function experiments, we showed that miR-483-3p could regulate mitochondrial respiratory Complex II expression, suggesting its role in OXPHOS regulation. Functionally, miR-483-3p overexpression could rescue imatinib-induced cell death. These findings provide the molecular link for imatinib-induced OXPHOS expression and the biological role of miR-483-3p in regulating cell viability upon imatinib treatment.

Long Noncoding RNA TTC39A-AS1 Promotes Breast Cancer Tumorigenicity by Sponging MicroRNA-483-3p and Thereby Upregulating MTA2

INTRODUCTION

In recent years, the regulatory activities of long noncoding RNAs have received increasing attention as an important research focus. This study aimed to characterize the expression and detailed roles of TTC39A antisense RNA 1 (TTC39A-AS1) in breast cancer (BC), in addition to concentrating on its downstream mechanisms.

METHODS

Quantitative RT-PCR was performed to determine the expression levels of TTC39A-AS1, microRNA-483-3p (miR-483-3p), and metastasis-associated gene 2 (MTA2). Further, the detailed functions of TTC39A-AS1 in BC cells were confirmed using the Cell Counting Kit 8 assay, flow cytometric analysis, and Transwell cell migration and invasion assays. The targeting relationship between TTC39A-AS1, miR-483-3p, and MTA2 in BC was predicted via bioinformatics analysis and further confirmed by performing the luciferase reporter assay and RNA immunoprecipitation.

RESULTS

TTC39A-AS1 was present in high levels in BC; this result was confirmed in our sample cohort and The Cancer Genome Atlas database. Patients with BC with a high level of TTC39A-AS1 had a shorter overall survival than those with a low level of TTC39A-AS1. Functionally, the absence of TTC39A-AS1 accelerated cell apo-ptosis but retained cell proliferation, migration, and invasion. Mechanistically, TTC39A-AS1 functioned as a competing endogenous RNA in BC by sponging miR-483-3p and thereby indirectly increasing MTA2 expression. Finally, rescue experiments revealed that the tumor-inhibiting actions of TTC39A-AS1 knockdown on the malignant characteristics of BC cells could be reversed by inhibiting miR-483-3p or upregulating MTA2.

CONCLUSION

The newly identified TTC39A-AS1/miR-483-3p/MTA2 pathway was revealed to be a critical regulator in the tumorigenicity of BC, possibly offering a novel therapeutic direction for the anticancer treatment of BC.

Comparative serum microRNA array analysis of the spleen-stomach dampness-heat syndrome in different diseases: Chronic hepatitis B and chronic gastritis

Spleen-stomach dampness-heat syndrome (SSDHS) is the common Traditional Chinese Medicine (TCM) syndrome observed in both chronic hepatitis B (CHB) and chronic gastritis (CG). The specialized TCM prescription for CHB and CG patients with SSDHS is same, but there is limited information about the biological characteristics of this TCM syndrome. This study aimed to identify the serum miRNAs profile for the SSDHS in two different diseases in order to evaluate the miRNA-mediated biological characteristics of this TCM syndrome. We performed comparative microarray analysis of serum miRNA expression profiles in 10 CHB patients with SSDHS (SSDHS-CHB), 10 CG patients with SSDHS (SSDHS-CG), and 10 healthy controls (HC). The selected miRNAs were further validated by qRT-PCR in 13 SSDHS-CHB patients, 13 SSDHS-CG patients, and 13 HC. Moreover, bioinformatics analysis (GO and KEGG pathway enrichment analyses) was applied to identify the involved target genes and pathways for these selected miRNAs. Nine significantly differentially expressed (SDE)-miRNAs in the SSDHS-CHB group and 24 SDE-miRNAs in the SSDHS-CG group were identified, compared with the HC group (fold change >2.0 and p < .05). Among these, upregulated hsa-miR-483-3p and downregulated hsa-miR-223-3p were identified as the common SDE-miRNAs for both SSDHS-CHB and SSDHS-CG groups. Bioinformatics analysis of the common SDE-miRNA's target genes showed their involvement in the regulation of inflammation, immune response, and tumorigenesis. SSDHS-specific hsa-miR-483-3p and hsa-miR-223-3p identified in this study indicated a relevance to the underlying biological basis of SSDHS, and may provide scientific basis for the application of same TCM prescription in CHB and CG.

MiR-205 suppressed the malignant behaviors of breast cancer cells by targeting CLDN11 via modulation of the epithelial-to-mesenchymal transition

Some Aberrant expression of miRNAs plays an important role in the occurrence and distant metastasis of breast cancer. This study aimed to identify crucial miRNA signatures for breast cancer using microarray data from the Gene Expression Omnibus database, including ductal carcinoma in situ and invasive duct carcinoma. In this study, we founded that miR-205 was significantly down-regulated in breast cancer, and the low expression of miR-205 was significantly associated with the TNM stage of breast cancer. In vitro, functional studies revealed that over-expression of miR-205 inhibited the proliferation and promoted apoptosis of breast cancer cells MDA-MB-231. Mechanistically, claudin 11 (CLDN11) was found to be the direct target of miR-205; the function of miR-205 could be exerted via downregulation of the target gene CLDN11 in breast cancer cells. Furthermore, the over-expression of miR-205 promoted the expression of the epithelial marker E-cadherin but reduced the mesenchymal markers in breast cancer cells. These results collectively indicated the tumor-suppressive role of miR-205 in breast cancer by targeting CLDN11; implying miR-205 may serve as a novel therapeutic target for breast cancer.

The clinical significance of histone deacetylase-8 in human breast cancer

Recent studies have shown that the histone deacetylase-8 (HDAC8), as one of the HDACs, regulates the expression and activity of various genes involved in cancer initiation and progression. The HDAC8 plays an epigenetic role to dysregulate expressions or to interact with transcription factors. Most researchers had focused on the HDAC 1-3 and 6, but today the HDAC8 isotype is a promising target in cancer therapy. Different studies, on breast cancer (BC) cells, have recently shown the HDAC8 overexpression and suggested its oncogenic potential. It seems that the HDAC8 could be a novel and promising target in breast cancer treatment. Some studies on BC demonstrated therapeutic properties of the inhibitors of HDAC8 such as suberoylanilide hydroxamic acid (SAHA), Trichostatin A, valproic acid, sodium butyrate, 1,3,4 oxadiazole with alanine hybrid [(R)-2-amino-N-((5-phenyl-1,3,4-oxadiazol-2-yl) methyl) propanamide (10b)], N-(2-Hydroxyphenyl)-2propylpentanamide (compound 2) and PCI-34051. In this review, we highlight the role and existing inhibitors of HDAC8 in BC pathogenesis and therapy.

Long non-coding RNA MIR100HG promotes the migration, invasion and proliferation of triple-negative breast cancer cells by targeting the miR-5590-3p/OTX1 axis

Background

As an aggressive subtype of breast cancer with a high risk of recurrence, triple-negative breast cancer (TNBC) lacks available treatment targets. LncRNA MIR100HG promotes cell proliferation in TNBC. However, few studies have investigated the molecular mechanism of MIR100HG in TNBC. Thus, additional in-depth investigations are needed to unravel its associated regulatory mechanism.

Methods

MIR100HG and miR-5590-3p expression in TNBC tissue samples and cell lines was detected by RT-qPCR. Flow cytometry, transwell, wound-healing, CCK8 and colony formation assays were performed to analyse cell apoptosis, cell cycle, invasion, migration and proliferation. The protein expression of orthodenticle homeobox 1 (OTX1) and proteins in the ERK/MAPK signalling pathway were assessed by western blot analysis. Bioinformatics and luciferase assay were performed to predict and validate the interaction between MIR100HG and miR-5590-3p as well as OTX1 and miR-5590-3p. RNA immunoprecipitation (RIP) was used to detect the interaction between MIR100HG and miR-5590-3p. Subcutaneous tumour growth was observed in nude mice. Immunohistochemistry (IHC) analysis was used to assess OTX1 expression in tumour tissues.

Results

MIR100HG expression was upregulated, whereas that of miR-5590-3p was downregulated in TNBC. MIR100HG was shown to directly interact with miR-5590-3p. Furthermore, MIR100HG knockdown could promote TNBC cell apoptosis and cell cycle arrest in G0/G1 phase while inhibiting migration, invasion and proliferation. Furthermore, miR-5590-3p inhibition showed the opposite results and could reverse the effect of MIR100HG knockdown in TNBC cells. MiR-5590-3p downregulated the ERK/MAPK signalling pathway, suppressed the migration, invasion and proliferation of TNBC cells and promoted their apoptosis and cell cycle arrest in G0/G1 phase by targeting OTX1. In addition, MIR100HG knockdown inhibited OTX1 expression by upregulating miR-5590-3p in vivo, thereby inhibiting tumour growth.

Conclusions

MIR100HG promotes the progression of TNBC by sponging miR-5590-3p, thereby upregulating OTX1, suggesting a new potential treatment target for TNBC.

Autophagic Vacuole Secretion Triggered by Chidamide Participates in TRAIL Apoptosis Effect in Breast Cancer Cells

BACKGROUND

Breast cancer is one of the most prevalent diseases threatening women's health today. Indepth research on breast cancer (BC) pathogenesis and prevention and treatment methods are gradually receiving attention. Chidamide is a novel histone deacetylase inhibitor (HDACi) that depresses the function of histone deacetylase, consequently affecting the growth of BC cells through epigenetic modification. However, preclinical and clinical studies show that chidamide is ineffective in long-term treatment. We demonstrated in previous experiments that TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis in BC cells and is significantly less non-toxic to normal cells than chidamide. Therefore, in this study, we treated BC cells with chidamide and TRAIL to explore a novel option to reduce the clinical toxicity through augmenting the sensitivity for BC cells.

METHODS AND RESULTS

Results from the MTT and cell viability assays indicated that the combination of chidamide and TRAIL in MCF-7 and MDA-MB-231 cells induced BC cell death, while maintaining a reduced concentration of chidamide. Autophagy assay and annexin V analysis showed that the autophagosome microtubuleassociated protein1light chain3-II (LC3-II) was abnormally increased and much more early and late phase of apoptotic cells appeared during chidamide and TRAIL induction. Anti-tumor assays in a BC tumor xenograft model displayed that the mixture of chidamide and TRAIL exhibited stronger effects on inhibiting tumor growth. The data from real-time PCR and western blotting showed that the cytotoxic effect correlated with the expressions of related apoptosis and autophagy factors.

CONCLUSION

Our data are the first to demonstrate the synergistic effects of chidamide and TRAIL in BC cells, specifically, the pharmacological effects on cell death induction. These results lay a solid experimental and theoretical basis to solve the clinical resistance of chidamide.

MiR-646 prevents proliferation and progression of human breast cancer cell lines by suppressing HDAC2 expression

BACKGROUND

Breast cancer is a type of cancer with a high incidence and mortality rate worldwide. Change in epigenetic mechanisms enhances cancer cell progression. Histon deacetylase 2 (HDAC2) was found to act as a potential oncogene in different malignancies. For better understanding the mechanisms related to breast cancer development, we investigated the role of HDAC2 in breast cancer and the inhibitory effect of miR-646 on this oncogene.

METHODS

A total of thirty cancerous tissues and 30 adjacent non-cancerous specimens and also three breast cancer cell lines were enrolled in the study. Quantitative reverse transcriptase PCR (qRT-PCR) was employed to detect the HDAC2 and miR-646 expression level in the studied samples. The biological roles of HDAC2 and miR-646 were investigated through manipulating the expression level of HDAC2 or miR-646 in breast cancer cells. Finally, we evaluated whether the HDAC2 is a direct target for miR-646.

RESULTS

In this study, we found HDAC2 is significantly upregulated in cancerous specimens and cell lines compared to non-cancerous tissues and normal cell line. On the other hand, miR-646 expression was decreased in clinical specimens and breast cancer cells compared to non-cancerous samples. Knocking out of the HDAC2 and overexpression of miR-646 inhibited breast cancer cell growth but promoted cell death, while untreated groups showed inverse results. Furthermore, we showed that in the breast cancer cells, miR-646 regulates the progression and proliferation by suppressing HDAC2.

CONCLUSION

Taken together, our study identified a miR-646/HDAC2 regulatory function in the breast cancer development and introduced a therapeutically target for breast cancer.

MiR-27a-3p Targeting GSK3β Promotes Triple-Negative Breast Cancer Proliferation and Migration Through Wnt/β-Catenin Pathway

BACKGROUND

Dysregulation of microRNAs (miRNAs) was found to play crucial roles in varieties of cancers, which affect tumor proliferation and migration. MiR-27a-3p has been identified as a tumor-related miRNA in liver cancer, lung cancer, and colorectal cancer. However, the function of miR-27a-3p in triple-negative breast cancer (TNBC) and its possible molecular mechanisms have still not been elucidated.

METHODS

QRT-PCR technique was used to detect the expression of miR-27a-3p in TNBC and normal breast cell lines or the effects of miR-27a-3p knockdown and overexpression in TNBC cell lines. Proliferation and migration were measured by CCK-8 method, colony formation, wound healing, and Transwell assays, respectively. Furthermore, we used a dual-luciferase reporter gene assay and Western blot analysis to identify GSK3β as a target of miR-27a-3p.

RESULTS

In this study, we found that miR-27a-3p expression was significantly elevated in TNBC cell lines. Database analysis suggested that TNBC patients with a high expression of miR-27a-3p have poorer overall survival possibilities. Overexpression of miR-27a-3p promotes TNBC cells proliferation, colony formation, and cell migration in vitro. Nevertheless, dual-luciferase reporter result showed that miR-27a-3p directly targeted the 3'-UTR regions of GSK3β mRNA and negatively regulated its expression. Lastly, we demonstrated that miR-27a-3p inactivates Wnt/β-catenin signaling pathway via targeting GSK3β.

CONCLUSION

These results indicate that expression of miR-27a-3p was highly expressed in TNBC and promoted tumor progression through attenuating GSK3β and may have a potential molecular-targeted strategy for TNBC therapy.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

MicroRNAs in cancer therapy: Their involvement in oxaliplatin sensitivity/resistance of cancer cells with a focus on colorectal cancer

The resistance of cancer cells into chemotherapy has restricted the efficiency of anti-tumor drugs. Oxaliplatin (OX) being an anti-tumor agent/drug is extensively used in the treatment of various cancer diseases. However, its frequent application has led to chemoresistance. As a consequence, studies have focused in finding underlying molecular pathways involved in OX resistance. MicroRNAs (miRs) are short endogenous non-coding RNAs that are able to regulate vital biological mechanisms such as cell proliferation and cell growth. The abnormal expression of miRs occurs in pathological events, particularly cancer. In the present review, we describe the involvement of miRs in OX resistance and sensitivity. The miRs are able to induce the oncogene factors and mechanisms, resulting in stimulation OX chemoresistance. Also, onco-suppressor miRs can enhance the sensitivity of cancer cells into OX chemotherapy and trigger apoptosis and cell cycle arrest, leading to reduced viability and progression of cancer cells. MiRs can also enhance the efficacy of OX chemotherapy. It is worth mentioning that miRs affect various down-stream targets in OX resistance/sensitivity such as STAT3, TGF-β, ATG4B, FOXO1, LATS2, NF-κB and so on. By identification of these miRs and their upstream and down-stream mediators, further studies can focus on targeting them to sensitize cancer cells into OX chemotherapy and induce apoptotic cell death.

Knockdown of ADAMDEC1 inhibits the progression of glioma in vitro

BACKGROUND

Glioma is one of the most lethal malignant tumors all over the world. The prognosis of patients with high‑grade glioma remains very poor. Therefore, it is urgent to find a novel strategy for the treatment of glioma. It has been reported that ADAMDEC1 could regulate the progression of multiple diseases, including cancers. However, the role of ADAMDEC1 during the tumorigenesis of glioma remains largely unknown. Methods, Gene expression of ADAMDEC1 in glioma tissues or in cells was detected by qRT-PCR. Western blot was performed to measure the protein expressions of p53, active caspase3, active caspase9, CDK2 and Cyclin A in glioma cells. Cell proliferation was detected by CCK-8 assay. Cell apoptosis or cycle was tested by flow cytometry. Transwell was used to test the invasion of glioma cells.

RESULTS

The expression of ADAMDEC1 in glioma tissues or cells was significantly upregulated. In addition, downregulation of ADAMDEC1 notably inhibited the proliferation and induced apoptosis of glioma cells through upregulation of active caspase 3 and active caspase 9. Besides, silencing of ADAMDEC1 obviously induced G1 arrest in glioma cells via modulation of cell cycle-related proteins. Finally, knockdown of ADAMDEC1 significantly inhibited the migration and invasion of glioma cells. In contrast, overexpression of ADAMDEC1 promoted cell proliferation, migration and invasion of glioma cells.

CONCLUSION

Downregulation of ADAMDEC1 could significantly inhibit the tumorigenesis of glioma in vitro, which may serve as a novel target for the treatment of glioma.

Downregulation of miR-575 Inhibits the Tumorigenesis of Gallbladder Cancer via Targeting p27 Kip1

Background

Gallbladder cancer (GBC) is the most common biliary tract malignant cancer worldwide. It has been reported that microRNA-575 (miR-575) was involved in the tumorigenesis of many cancers. However, the role of miR-575 during the progression of GBC remains largely unknown.

Methods

The expression of miR-575 in GBC cells was detected by quantitative real-time polymerase chain reaction. The proliferation of GBC cells was examined by CCK-8 assay and Ki-67 staining. Apoptosis of GBC cells was measured by flow cytometry, and cell invasion was tested by transwell assay. Moreover, protein expressions in GBC cells were evaluated using Western blot. The target gene of miR-575 was predicted using Targetscan and miRDB. Finally, xenograft tumor model was established to verify the function of miR-575 in GBC in vivo.

Results

Our findings indicated that miR-575 antagonist decreased the proliferation and invasion of GBC cells. In addition, miR-575 antagonist significantly induced apoptosis of GBC cells via inducing G1 arrest. Meanwhile, p27 Kip1 was found to be a direct target of miR-575 with luciferase reporter assay. Moreover, miR-575 antagonist significantly decreased the expressions of CDK1 and cyclin E1 and upregulated the levels of cleaved caspase3 and p27 Kip1 in GBC cells. Finally, miR-575 antagonist notably suppressed GBC tumor growth in vivo.

Conclusion

Downregulation of miR-575 significantly inhibited the tumorigenesis of GBC via targeting p27 Kip1. Thus, miR-575 might be a potential novel target for the treatment of GBC.

Wnt-regulating microRNAs role in gastric cancer malignancy

Gastric cancer (GC) is responsible for high morbidity and mortality worldwide. This cancer claims fifth place among other cancers. There are a number of factors associated with GC development such as alcohol consumption and tobacco smoking. It seems that genetic factors play significant role in GC malignancy and progression. MicroRNAs (miRs) are short non-coding RNA molecules with negative impact on the expression of target genes. A variety of studies have elucidated the potential role of miRs in GC growth. Investigation of molecular pathways has revealed that miRs function as upstream modulators of Wnt signaling pathway. This signaling pathway involves in important biological processes such as cell proliferation and differentiation, and its dysregulation is associated with GC invasion. At the present review, we demonstrate that how miRs regulate Wnt signaling pathway in GC malignancy.

MiR-483 Targeted SOX3 to Suppress Glioma Cell Migration, Invasion and Promote Cell Apoptosis

Objective

Glioma is the most common malignant brain tumor that has high aggressiveness. The aim of this study was to investigate the potential therapeutic targets for gliomas.

Materials and Methods

Real-time quantitative polymerase chain reaction (RT-qPCR) was employed to calculate the expression of miRNA and genes. The connection between the expression of miR-483 and patients' overall survival rate was evaluated using Kaplan-Meier analysis. In addition, the underlying mechanism was detected using luciferase assay.

Results

The expression level of miR-483 was significantly decreased in glioma tissue samples and cell lines, compared to the adjacent tissues and normal cell lines. Downregulation of miR-483 or upregulation of SOX3 was associated with overall survival of glioma patients. Additionally, overexpression of miR-483 promotes cell invasion and migration and inhibits apoptosis. In addition, miR-483 directly targeted to SOX3, and the expression of miR-483 has a negative correlation with SOX3 in glioma tissues. SOX3 reversed partial functions of miR-483 on cell migration, invasion, and promoted cell apoptosis in glioma.

Conclusion

MiR-483 inhibited glioma cell migration, invasion, and promoted glioma cell apoptosis by targeting SOX3. MiR-483 maybe acted as a potential target for the treatment of glioma.

Long noncoding RNA NR2F1-AS1 enhances the malignant properties of osteosarcoma by increasing forkhead box A1 expression via sponging of microRNA-483-3p

The long noncoding RNA NR2F1-AS1 has been found to promote the development of hepatocellular carcinoma and endometrial cancer. In this study, we measured NR2F1-AS1 expression in osteosarcoma (OS), determined the involvement of NR2F1-AS1 in the malignant properties of OS, and investigated the underlying mechanisms. NR2F1-AS1 was found to be upregulated in OS tumors and cell lines. The increased NR2F1-AS1 level was closely associated with advanced clinical stage and distant metastasis in patients with OS. Patients with OS in an NR2F1-AS1 high-expression group demonstrated significantly shorter overall survival than did patients in an NR2F1-AS1 low-expression group. NR2F1-AS1 knockdown inhibited OS cell proliferation, migration, and invasion and promoted cell cycle arrest and apoptosis in vitro and slowed tumor growth in vivo. NR2F1-AS1 was found to function as a competing endogenous RNA by directly sponging microRNA-483-3p (miR-483-3p) and upregulating its target oncogene forkhead box A1 (FOXA1). Finally, rescue experiments revealed that knockdown of miR-483-3p and recovery of FOXA1 expression both attenuated the influence of the NR2F1-AS1 knockdown on OS cells. Thus, NR2F1-AS1 plays an oncogenic role in OS through sponging miR-483-3p and thereby upregulating FOXA1, suggesting an additional target for osteosarcoma therapeutics.