ErbB2 signaling epigenetically suppresses microRNA-205 transcription via Ras/Raf/MEK/ERK pathway in breast cancer

Dynamic characterization of circulating tumor DNA in HER2-altered advanced non-small cell lung cancer treated with pyrotinib and apatinib: Exploratory biomarker analysis from PATHER2 study

BACKGROUND

HER2 mutations are critical drivers of non-small cell lung cancer (NSCLC), affecting 2 %-3 % of patients and often leads to poor prognosis and limited response to conventional therapies. This study investigates the genomic characteristics and prognostic relevance of dynamic circulating tumor DNA (ctDNA) monitoring in advanced NSCLC patients with HER2 mutations treated with pyrotinib and apatinib.

METHODS

The PATHER2 study included 33 advanced NSCLC patients harboring HER2 mutations or amplification, who received combination therapy of pyrotinib and apatinib. Among them, 27 patients had baseline blood samples available for analysis. Baseline blood samples (n = 27), follow-up samples after one treatment cycle (n = 13), and samples upon disease progression (n = 18) were collected. ctDNA was extracted and sequenced using a 556-gene panel.

RESULTS

At baseline, HER2 mutations were detected in 21 of 27 patients through ctDNA, and 19 showed consistent results between tissue and blood sample testing. Patients with TP53 and DNMT3A alterations at baseline had significantly shorter progression-free survival (PFS). Dynamic ctDNA monitoring revealed that patients without detectable HER2 mutations after one treatment cycle had longer PFS and a trend toward longer overall survival (OS) compared to those with persistent HER2 mutations. The newly emerged mutations after resistance were infrequently found in HER2, instead primarily enriched in the chromatin remodeling pathway.

CONCLUSION

ctDNA holds significant value in guiding the treatment of patients with HER2 mutations. Baseline TP53 and DNMT3A alterations, along with persistent HER2 mutations after initial treatment, are associated with poorer prognosis. The primary mechanism of resistance to pyrotinib and apatinib in these patients may be attributed to chromatin remodeling rather than on-target alterations.

Interaction of GPER-1 with the endocrine signaling axis in breast cancer

G Protein-Coupled Estrogen Receptor 1 (GPER-1) is a membrane estrogen receptor that has emerged as a key player in breast cancer development and progression. In addition to its direct influence on estrogen signaling, a crucial interaction between GPER-1 and the hypothalamic-pituitary-gonadal (HPG) axis has been evidenced. The novel and complex relationship between GPER-1 and HPG implies a hormonal regulation with important homeostatic effects on general organ development and reproductive tissues, but also on the pathophysiology of cancer, especially breast cancer. Recent research points to a great versatility of GPER-1, interacting with classical estrogen receptors and with signaling pathways related to inflammation. Importantly, through its activation by environmental and synthetic estrogens, GPER-1 is associated with hormone therapy resistance in breast cancer. These findings open new perspectives in the understanding of breast tumor development and raise the possibility of future applications in the design of more personalized and effective therapeutic approaches.

Applying a Gene Reversal Rate Computational Methodology to Identify Drugs for a Rare Cancer: Inflammatory Breast Cancer

The aim of this study was to utilize a computational methodology based on Gene Reversal Rate (GRR) scoring to repurpose existing drugs for a rare and understudied cancer: inflammatory breast cancer (IBC). This method uses IBC-related gene expression signatures (GES) and drug-induced gene expression profiles from the LINCS database to calculate a GRR score for each candidate drug, and is based on the idea that a compound that can counteract gene expression changes of a disease may have potential therapeutic applications for that disease. Genes related to IBC with associated differential expression data (265 up-regulated and 122 down-regulated) were collated from PubMed-indexed publications. Drug-induced gene expression profiles were downloaded from the LINCS database and candidate drugs to treat IBC were predicted using their GRR scores. Thirty-two (32) drug perturbations that could potentially reverse the pre-compiled list of 297 IBC genes were obtained using the LINCS Canvas Browser (LCB) analysis. Binary combinations of the 32 perturbations were assessed computationally to identify combined perturbations with the highest GRR scores, and resulted in 131 combinations with GRR greater than 80%, that reverse up to 264 of the 297 genes in the IBC-GES. The top 35 combinations involve 20 unique individual drug perturbations, and 19 potential drug candidates. A comprehensive literature search confirmed 17 of the 19 known drugs as having either anti-cancer or anti-inflammatory activities. AZD-7545, BMS-754807, and nimesulide target known IBC relevant genes: PDK, Met, and COX, respectively. AG-14361, butalbital, and clobenpropit are known to be functionally relevant in DNA damage, cell cycle, and apoptosis, respectively. These findings support the use of the GRR approach to identify drug candidates and potential combination therapies that could be used to treat rare diseases such as IBC.

miR-205-5p inhibits homocysteine-induced pulmonary microvascular endothelium dysfunction by targeting FOXO1

Homocysteine (Hcy) is a risk factor for multiple chronic diseases, and vascular endothelial cell injury has been regarded as the initiating step for this process. miRNAs are involved in Hcy-induced endothelial dysfunction, while the underlying mechanism and roles of miRNAs in pulmonary endothelial dysfunction induced by homocysteine are unknown. Here, we find that miR-205-5p alleviates pulmonary endothelial dysfunction by targeting FOXO1 in CBS +/‒ mice to protect against Hcy-induced pulmonary endothelial dysfunction. Mechanistically, we show that Hcy can lead to DNA hypermethylation of the miR-205-5p promoter due to the increased binding of DNMT1 to its promoter, which contributes to reduction of miR-205-5p expression. In summary, miR-205-5p promoter hypermethylation causes downregulation of miR-205-5p expression, resulting in a reduction in miR-205-5p binding to FOXO1 during homocysteine-induced pulmonary endothelial dysfunction. Our data indicate that miR-205-5p may be a potential therapeutic target against Hcy-induced pulmonary injury.

The Mechanism of DNA Methylation and miRNA in Breast Cancer

Breast cancer is the most prevalent cancer in the world. Currently, the main treatments for breast cancer are radiotherapy, chemotherapy, targeted therapy and surgery. The treatment measures for breast cancer depend on the molecular subtype. Thus, the exploration of the underlying molecular mechanisms and therapeutic targets for breast cancer remains a hotspot in research. In breast cancer, a high level of expression of DNMTs is highly correlated with poor prognosis, that is, the abnormal methylation of tumor suppressor genes usually promotes tumorigenesis and progression. MiRNAs, as non-coding RNAs, have been identified to play key roles in breast cancer. The aberrant methylation of miRNAs could lead to drug resistance during the aforementioned treatment. Therefore, the regulation of miRNA methylation might serve as a therapeutic target in breast cancer. In this paper, we reviewed studies on the regulatory mechanisms of miRNA and DNA methylation in breast cancer from the last decade, focusing on the promoter region of tumor suppressor miRNAs methylated by DNMTs and the highly expressed oncogenic miRNAs inhibited by DNMTs or activating TETs.

Nucleocytoplasmic transport of active HER2 causes fractional escape from the DCIS-like state

Activation of HER2/ErbB2 coincides with escape from ductal carcinoma in situ (DCIS) premalignancy and disrupts 3D organization of cultured breast-epithelial spheroids. The 3D phenotype is infrequent, however, and mechanisms for its incomplete penetrance have been elusive. Using inducible HER2/ErbB2-EGFR/ErbB1 heterodimers, we match phenotype penetrance to the frequency of co-occurring transcriptomic changes and uncover a reconfiguration in the karyopherin network regulating ErbB nucleocytoplasmic transport. Induction of the exportin CSE1L inhibits nuclear accumulation of ErbBs, whereas nuclear ErbBs silence the importin KPNA1 by inducing miR-205. When these negative feedbacks are incorporated into a validated systems model of nucleocytoplasmic transport, steady-state localization of ErbB cargo becomes ultrasensitive to initial CSE1L abundance. Erbb2-driven carcinomas with Cse1l deficiency outgrow less irregularly from mammary ducts, and NLS-attenuating mutants or variants of HER2 favor escape in 3D culture. We conclude here that adaptive nucleocytoplasmic relocalization of HER2 creates a systems-level molecular switch at the premalignant-to-malignant transition.

miR-145, miR-205 and miR-451: potential tumor suppressors involved in the progression of in situ to invasive carcinoma of the breast

BACKGROUND

MicroRNAs (miRNAs) control diverse biologic processes during tumor progression. This study was conducted to identify miRNAs that are implicated in progression of in situ to invasive breast cancer (IBC) and to evaluate their association with clinicopathological features of ductal carcinoma in situ (DCIS).

METHODS

We performed miRNA microarray analyses to find differentially expressed miRNAs between DCIS and IBC in a test set, and validated expression levels of selected miRNAs using a different set of tumors. Finally, we evaluated the relationship between clinicopathological features and the expression of selected miRNAs in DCIS samples.

RESULTS

We found that miR-145-5p, miR-205-5p and miR-451a are significantly down-regulated in IBC compared to DCIS in the whole group, and in the estrogen receptor (ER)-positive and ER-negative subgroups. In a validation set, miR-145, miR-205, and miR-451 also showed lower expression levels in IBC than in DCIS, irrespective of ER status. Moreover, their expression levels were significantly lower in the invasive component compared to the in situ component within same tumors. MiR-145, miR-205 and miR-451 commonly showed lower expression levels in DCIS with positive HER2 status and high Ki-67 proliferation index. Especially, miR-145 and miR-205 showed lower expression levels in DCIS with microinvasion, compared to pure DCIS. In addition, lower miR-205 expression level was associated with high nuclear grade, comedo type necrosis, and hormone receptor negativity.

CONCLUSIONS

Our study showed that miR-145, miR-205 and miR-451 expression decreased in IBC compared to DCIS, and their expression levels were low in DCIS with high-risk features for progression, implying their contributions in the progression of DCIS to invasive carcinoma as tumor suppressors.

miR-34a-5p functions as a tumor suppressor in head and neck squamous cell cancer progression by targeting Flotillin-2

While a number of therapeutic advances have been made in recent years, the overall survival of patients with head and neck squamous cell cancer (HNSCC) remains poor. MicroRNAs (miRNAs) are key drivers of oncogenic progression, with miR-34a-5p downregulation having been observed in many different tumor types. Here, we assessed the link between miR-34a-5p and HNSCC progression and the mechanistic basis for this relationship. Levels of miR-34a-5p in HNSCC tumors and cell lines were assessed via qPCR, after which we explored the functional importance of this miRNA in this oncogenic setting. Through luciferase reporter assays, the ability of miR-34a-5p to regulate flotillin-2 (FLOT-2) was further clarified. Overall, these analyses revealed that HNSCC tumors and cells exhibited marked miR-34a-5p downregulation that was linked to the progression of this tumor type. At a functional level, miR-34a-5p constrained the proliferation, migratory/invasive activity, and epithelial-mesenchymal transition induction in HNSCC cells. At the mechanistic level, miR-34a-5p was found to suppress FLOT-2 expression and to activate the MEK/ERK1/2 pathway. Overall, these results suggest that miR-34a-5p can function as a tumor suppressor miRNA in HNSCC owing to its ability to target FLOT-2, highlighting the promise of targeting this regulatory axis to treat HNSCC.

Selective Extracellular Signal-Regulated Kinase 1/2 (ERK1/2) Inhibition by the SCH772984 Compound Attenuates In Vitro and In Vivo Inflammatory Responses and Prolongs Survival in Murine Sepsis Models

Sepsis is the leading cause of death in intensive care units worldwide. Current treatments of sepsis are largely supportive and clinical trials using specific pharmacotherapy for sepsis have failed to improve outcomes. Here, we used the lipopolysaccharide (LPS)-stimulated mouse RAW264.7 cell line and AlphaLisa assay for TNFa as a readout to perform a supervised drug repurposing screen for sepsis treatment with compounds targeting epigenetic enzymes, including kinases. We identified the SCH772984 compound, an extracellular signal-regulated kinase (ERK) 1/2 inhibitor, as an effective blocker of TNFa production in vitro. RNA-Seq of the SCH772984-treated RAW264.7 cells at 1, 4, and 24 h time points of LPS challenge followed by functional annotation of differentially expressed genes highlighted the suppression of cellular pathways related to the immune system. SCH772984 treatment improved survival in the LPS-induced lethal endotoxemia and cecal ligation and puncture (CLP) mouse models of sepsis, and reduced plasma levels of Ccl2/Mcp1. Functional analyses of RNA-seq datasets for kidney, lung, liver, and heart tissues from SCH772984-treated animals collected at 6 h and 12 h post-CLP revealed a significant downregulation of pathways related to the immune response and platelets activation but upregulation of the extracellular matrix organization and retinoic acid signaling pathways. Thus, this study defined transcriptome signatures of SCH772984 action in vitro and in vivo, an agent that has the potential to improve sepsis outcome.

Epigenetic Regulation of Breast Cancer Stem Cells Contributing to Carcinogenesis and Therapeutic Implications

Globally, breast cancer has remained the most commonly diagnosed cancer and the leading cause of cancer death among women. Breast cancer is a highly heterogeneous and phenotypically diverse group of diseases, which require different selection of treatments. Breast cancer stem cells (BCSCs), a small subset of cancer cells with stem cell-like properties, play essential roles in breast cancer progression, recurrence, metastasis, chemoresistance and treatments. Epigenetics is defined as inheritable changes in gene expression without alteration in DNA sequence. Epigenetic regulation includes DNA methylation and demethylation, as well as histone modifications. Aberrant epigenetic regulation results in carcinogenesis. In this review, the mechanism of epigenetic regulation involved in carcinogenesis, therapeutic resistance and metastasis of BCSCs will be discussed, and finally, the therapies targeting these biomarkers will be presented.

Regulation of breast cancer metastasis signaling by miRNAs

Despite the decline in death rate from breast cancer and recent advances in targeted therapies and combinations for the treatment of metastatic disease, metastatic breast cancer remains the second leading cause of cancer-associated death in U.S. women. The invasion-metastasis cascade involves a number of steps and multitudes of proteins and signaling molecules. The pathways include invasion, intravasation, circulation, extravasation, infiltration into a distant site to form a metastatic niche, and micrometastasis formation in a new environment. Each of these processes is regulated by changes in gene expression. Noncoding RNAs including microRNAs (miRNAs) are involved in breast cancer tumorigenesis, progression, and metastasis by post-transcriptional regulation of target gene expression. miRNAs can stimulate oncogenesis (oncomiRs), inhibit tumor growth (tumor suppressors or miRsupps), and regulate gene targets in metastasis (metastamiRs). The goal of this review is to summarize some of the key miRNAs that regulate genes and pathways involved in metastatic breast cancer with an emphasis on estrogen receptor α (ERα+) breast cancer. We reviewed the identity, regulation, human breast tumor expression, and reported prognostic significance of miRNAs that have been documented to directly target key genes in pathways, including epithelial-to-mesenchymal transition (EMT) contributing to the metastatic cascade. We critically evaluated the evidence for metastamiRs and their targets and miRNA regulation of metastasis suppressor genes in breast cancer progression and metastasis. It is clear that our understanding of miRNA regulation of targets in metastasis is incomplete.

miR-205 in Breast Cancer: State of the Art

Despite its controversial roles in different cancer types, miR-205 has been mainly described as an oncosuppressive microRNA (miRNA), with some contrasting results, in breast cancer. The role of miR-205 in the occurrence or progression of breast cancer has been extensively studied since the first evidence of its aberrant expression in tumor tissues versus normal counterparts. To date, it is known that the expression of miR-205 in the different subtypes of breast cancer is decreasing from the less aggressive subtype, estrogen receptor/progesterone receptor positive breast cancer, to the more aggressive, triple negative breast cancer, influencing metastasis capability, response to therapy and patient survival. In this review, we summarize the most important discoveries that have highlighted the functional role of this miRNA in breast cancer initiation and progression, in stemness maintenance, in the tumor microenvironment, its potential role as a biomarker and its relevance in normal breast physiology—the still open questions. Finally, emerging evidence reveals the role of some lncRNAs in breast cancer progression as sponges of miR-205. Here, we also reviewed the studies in this field.

The Therapeutic Potential of MicroRNAs in Cancer: Illusion or Opportunity?

The functional involvement of microRNAs in human neoplasia has raised in the last years an increasing interest in the scientific community toward the potential application in clinics as therapeutic tools. Indeed, the possibility to modulate their expression to re-establish a lost equilibrium and counteract tumor growth and dissemination, and/or to improve responsiveness to standard therapies, is promising and fascinating. However, several issues need to be taken into account such as factors related to miRNA stability in the blood, tissue penetration and potential off-target effects, which might affect safety, tolerability and efficacy of an miRNA-based therapy. Here we describe the most relevant challenges related to miRNA-based therapy, review the delivery strategies exploited to date and the on-going clinical trials.

Unveiling the ups and downs of miR-205 in physiology and cancer: transcriptional and post-transcriptional mechanisms

miR-205 plays important roles in the physiology of epithelia by regulating a variety of pathways that govern differentiation and morphogenesis. Its aberrant expression is frequently found in human cancers, where it was reported to act either as tumor-suppressor or oncogene depending on the specific tumor context and target genes. miR-205 expression and function in different cell types or processes are the result of the complex balance among transcription, processing and stability of the microRNA. In this review, we summarize the principal mechanisms that regulate miR-205 expression at the transcriptional and post-transcriptional level, with particular focus on the transcriptional relationship with its host gene. Elucidating the mechanisms and factors regulating miR-205 expression in different biological contexts represents a fundamental step for a better understanding of the contribution of such pivotal microRNA to epithelial cell function in physiology and disease, and for the development of modulation strategies for future application in cancer therapy.

Prognostic Role of microRNA-205 in Human Gynecological Cancer: A Meta-Analysis of Fourteen Studies

Several studies have revealed that miR-205 plays important roles in the development of gynecological cancers and thus may serve as a potential prognostic biomarker, but the current conclusions remain controversial. Therefore, the goal of this study was to explore the prognostic significance and functional mechanisms of miR-205 based on a meta-analysis and bioinformatics investigation. A total of 14 published studies containing 5835 patients were enrolled by searching the PubMed, EMBASE, and Cochrane library databases, 13 (14 datasets) and 5 (6 datasets) of which evaluated the correlations between the expression level of miR-205 and overall survival (OS) or disease-free survival (DFS)/disease-specific survival (DSS)/progression-free survival (PFS)/distant metastasis-free survival (DMFS), respectively. Furthermore, the use of online Kaplan-Meier plotter database analysis supplemented another seven results for OS. Then, a meta-analysis using these 21 and 6 datasets was performed. As a result, the overall analysis failed to demonstrate any significant associations between miR-205 expression and OS (p = 0.267) or DSS/DFS/DMFS/PFS (p = 0.457), but the subgroup analysis suggested that elevated miR-205 predicted a reduced OS for breast cancer (BC) patients (hazard ratio [HR] = 0.84, 95% confidence interval [CI] = 0.72-0.98; p = 0.022), while higher miR-205 was associated with a poor DSS for endometrial cancer (EC) patients (HR = 2.19, 95% CI = 1.45-3.32; p < 0.001). Function prediction analysis indicated that miR-205 may be involved in BC by negatively influencing hub genes, SMARCA5 and SIAH1, whereas miR-205 may participate in EC by negatively modulating BMPR1B because of the presence of interactions of miR-205 with them at 3'-untranslated region and their opposite prognosis outcomes with miR-205. In conclusion, our findings suggest miR-205 may be a promising prognostic biomarker and therapeutic target for BC and EC patients.

A miR-205-LPCAT1 axis contributes to proliferation and progression in multiple cancers

In the past two decades, miRNAs have been demonstrated to play critical roles in development and progression of malignant diseases. To identify the role and mechanism of miRNA are urgent for the application of miRNA-based therapeutics in cancers. MiR-205 is a conserved miRNA from the invertebrate to mammalian species. Previous studies showed a large body of evidence to demonstrate the oncogenic or tumor suppressive role of it in different types of cancers. Our aim here is to clarify the role and novel mechanism of miR-205 in solid tumors. In the present study, we found that a high level of miR-205 is an independent biomarker for favorable prognosis in LIHC, HNSCC and LUSC. In the functional experiment, we stably expressed miR-205 in tumor cell lines derived from above mentioned cancers. The result showed that overexpression of miR-205 significantly inhibits cancer cell proliferation. Mechanistically, we identified that the lysophosphatidylcholine acyltransferase-1 (LPCAT1) is a novel target of miR-205 in multiple cancer cells. Furthermore, we found that LPCAT1 is required for sustained proliferation of cancer cells and a high level of it is closely associated with poor prognosis in clinical patients. Collectively, we revealed the important prognostic value of a miR-205-LPCAT1 axis in multiple cancers and highlighted an essential role of LPCAT1 in miR-205-regulated cancer cell proliferation. All these discoveries make a miR-205-LPCAT1 axis to shed light upon a potential therapeutic target in cancer treatment.

MiR-205 Dysregulations in Breast Cancer: The Complexity and Opportunities

MicroRNAs (miRNAs) are endogenous non-coding small RNAs that downregulate target gene expression by imperfect base-pairing with the 3' untranslated regions (3'UTRs) of target gene mRNAs. MiRNAs play important roles in regulating cancer cell proliferation, stemness maintenance, tumorigenesis, cancer metastasis, and cancer therapeutic resistance. While studies have shown that dysregulation of miRNA-205-5p (miR-205) expression is controversial in different types of human cancers, it is generally observed that miR-205-5p expression level is downregulated in breast cancer and that miR-205-5p exhibits a tumor suppressive function in breast cancer. This review focuses on the role of miR-205-5p dysregulation in different subtypes of breast cancer, with discussions on the effects of miR-205-5p on breast cancer cell proliferation, epithelial-mesenchymal transition (EMT), metastasis, stemness and therapy-resistance, as well as genetic and epigenetic mechanisms that regulate miR-205-5p expression in breast cancer. In addition, the potential diagnostic and therapeutic value of miR-205-5p in breast cancer is also discussed. A comprehensive list of validated miR-205-5p direct targets is presented. It is concluded that miR-205-5p is an important tumor suppressive miRNA capable of inhibiting the growth and metastasis of human breast cancer, especially triple negative breast cancer. MiR-205-5p might be both a potential diagnostic biomarker and a therapeutic target for metastatic breast cancer.

MicroRNAs Contribute to Breast Cancer Invasiveness

Cancer statistics in 2018 highlight an 8.6 million incidence in female cancers, and 4.2 million cancer deaths globally. Moreover, breast cancer is the most frequent malignancy in females and twenty percent of these develop metastasis. This provides only a small chance for successful therapy, and identification of new molecular markers for the diagnosis and prognostic prediction of metastatic disease and development of innovative therapeutic molecules are therefore urgently required. Differentially expressed microRNAs (miRNAs) in cancers cause multiple changes in the expression of the tumorigenesis-promoting genes which have mostly been investigated in breast cancers. Herein, we summarize recent data on breast cancer-specific miRNA expression profiles and their participation in regulating invasive processes, in association with changes in cytoskeletal structure, cell-cell adhesion junctions, cancer cell-extracellular matrix interactions, tumor microenvironments, epithelial-to-mesenchymal transitions and cancer cell stem abilities. We then focused on the epigenetic regulation of individual miRNAs and their modified interactions with other regulatory genes, and reviewed the function of miRNA isoforms and exosome-mediated miRNA transfer in cancer invasiveness. Although research into miRNA’s function in cancer is still ongoing, results herein contribute to improved metastatic cancer management.

MicroRNA-205-5p inhibits three-dimensional spheroid proliferation of ErbB2-overexpressing breast epithelial cells through direct targeting of CLCN3

We previously reported that microRNA-205-5p (miR-205-5p) is significantly decreased in the ErbB2-overexpressing breast epithelial cell line MCF10A-ErbB2 compared with control cells. In this study, we identified a direct target of miR-205-5p, chloride voltage-gated channel 3 (CLCN3). CLCN3 expression was induced by ErbB2 overexpression; this induced expression was then reduced to control levels by the transfection of the miR-205-5p precursor. In RNA-binding protein immunoprecipitation with Ago1/2/3 antibody, CLCN3 was significantly enriched in 293T embryonic kidney cells with miR-205-5p mimic transfection compared with negative control mimic transfection. In luciferase reporter assays using CLCN3 3'-UTR constructs, the miR-205-5p mimic significantly decreased reporter activity of both wild-type and partial mutant constructs in MCF10A-ErbB2 cells. In contrast, no inhibitory effects of the miR-205-5p mimic were detected using the complete mutant constructs. Since miR-205-5p expression in exosomes derived from MCF10A-neo cells was substantially higher than in exosomes derived from MCF10A-ErbB2 cells, we next investigated whether an exosome-mediated miR-205-5p transfer could control CLCN3 expression. To this end, exosomal miR-205-5p derived from MCF10A-neo cells was functionally transferred to MCF10A-ErbB2 cells, which served to decrease the expression of CLCN3. To assess the roles of CLCN3 in breast cancer, we next performed three-dimensional (3D) spheroid proliferation analyses using MCF10A-ErbB2 cells treated with MCF10A-neo-derived exosomes or CLCN3 shRNA stably expressing SKBR3 and MDA-MB-453 breast cancer cells. Our results showed that both treatment with MCF10A-neo-derived exosome and CLCN3 shRNA expression suppressed 3D spheroid proliferation. Collectively, these novel findings suggest that CLCN3 may be a novel direct target of miR-205-5p and this CLCN3/miR-205-5p interaction may serve a pivotal role in regulating breast cancer cellular proliferation under physiological conditions.

Ultrasound‑targeted microbubble destruction‑mediated miR‑205 enhances cisplatin cytotoxicity in prostate cancer cells

MicroRNAs (miRNAs) are non-coding ~20 nucleotides long sequences that function in the initiation and development of a number of cancers. Ultrasound-targeted microbubble destruction (UTMD) is an effective method for microRNA delivery. The aim of the present study was to investigate the potential roles of UTMD-mediated miRNA (miR)-205 delivery in the development of prostate cancer (PCa). In the present study, miR-205 expression was examined by reverse transcription-quantitative polymerase chain reaction assay. miR-205 mimics were transfected into PC-3 cells using the UTMD method, and the PC-3 cells were also treated with cisplatin. Cell proliferation, apoptosis, migration and invasion abilities were detected using Cell Counting kit-8, flow cytometry, wound healing and Transwell assays, respectively. In addition, the protein expression levels of caspase-9, cleaved-caspase 9, cytochrome c (cytoc), epithelial (E)-cadherin, matrix metalloproteinase-9 (MMP-9), phosphorylated (p)-extracellular signal-regulated kinase (ERK) and ERK were measured by western blot analysis. The results of the present study demonstrated that miR-205 expression was low in human PCa cell lines compared with healthy cells and that UTMD-mediated miR-205 delivery inhibited PCa cell proliferation, migration and invasion, and promoted apoptosis modulated by cisplatin compared with UTMD-mediated miR-negative control group and miR-205-treated group. Furthermore, it was demonstrated that UTMD-mediated miR-205 transfection increased the expression of caspase-9, cleaved-caspase 9, cytochrome c and E-cadherin, and decreased the expression of MMP-9 and p-ERK. Therefore, UTMD-mediated miR-205 delivery may be a promising method for the treatment of PCa.

miR372 Promotes Progression of Liver Cancer Cells by Upregulating erbB-2 through Enhancement of YB-1

MicroRNAs are known to be involved in carcinogenesis. Recently, microRNA-372 (miR372) has been proven to play a substantial role in several human cancers, but its functions in liver cancer remain unclear. Herein, our results demonstrate that miR372 accelerates growth of liver cancer cells in vitro and in vivo. Mechanistically, miR372 enhances expression of Y-box-binding protein 1 (YB-1) by targeting for phosphatase and tensin homolog (PTEN) directly and consequently promotes phosphorylation of YB-1 via HULC looping dependent on ERK1/2 and PTEN. In particular, HULC knockdown or PTEN overexpression abrogated this miR372 action. Moreover, miR372 inhibits the degradation of β-catenin dependent on phosphorylation of YB-1 and then enhances the expression and activity of pyruvate kinase M2 isoform (PKM2) by β-catenin-LEF/TCF4 pathway. Furthermore, the loading of LEF/TCF4 on PKM2 promoter region was significantly increased in miR372 overexpressing Hep3B, and thus, glycolytic proton efflux rate (glycoPER) was significantly increased in rLV-miR372 group compared to the rLV group. Moreover, β-catenin knockdown abrogates this function of miR372. Ultimately, miR372 promotes the expression of erbB-2 through PKM2-pH3T11-acetylation on histone H3 lysine 9 (H3K9Ac) pathway. Of significance, both YB-1 knockdown and erbB-2 knockdown abrogate oncogenic action of miR372. Our observations suggest that miR372 promotes liver cancer cell cycle progress by activating cyclin-dependent kinase 2 (CDK2)-cyclin E-P21/Cip1 complex through miR372-YB-1-β-catenin-LEF/TCF4-PKM2-erbB-2 axis. This study elucidates a novel mechanism for miR372 in liver cancer cells and suggests that miR372 can be used as a novel therapeutic target of liver cancer.