MicroRNA-21 promotes cell proliferation, migration, and resistance to apoptosis through PTEN/PI3K/AKT signaling pathway in esophageal cancer

Catalytic Knockdown of miR-21 by Artificial Ribonuclease: Biological Performance in Tumor Model

Control of the expression of oncogenic small non-coding RNAs, notably microRNAs (miRNAs), is an attractive therapeutic approach. We report a design platform for catalytic knockdown of miRNA targets with artificial, sequence-specific ribonucleases. miRNases comprise a peptide [(LeuArg)₂Gly]₂ capable of RNA cleavage conjugated to the miRNA-targeted oligodeoxyribonucleotide, which becomes nuclease-resistant within the conjugate design, without resort to chemically modified nucleotides. Our data presented here showed for the first time a truly catalytic character of our miR-21-miRNase and its ability to cleave miR-21 in a multiple catalytic turnover mode. We demonstrate that miRNase targeted to miR-21 (miR-21-miRNase) knocked down malignant behavior of tumor cells, including induction of apoptosis, inhibition of cell invasiveness, and retardation of tumor growth, which persisted on transplantation into mice of tumor cells treated once with miR-21-miRNase. Crucially, we discover that the high biological activity of miR-21-miRNase can be directly related not only to its truly catalytic sequence-specific cleavage of miRNA but also to its ability to recruit the non-sequence specific RNase H found in most cells to elevate catalytic turnover further. miR-21-miRNase worked synergistically even with low levels of RNase H. Estimated degradation in the presence of RNase H exceeded 10³ miRNA target molecules per hour for each miR-21-miRNase molecule, which provides the potency to minimize delivery requirements to a few molecules per cell. In contrast to the comparatively high doses required for the simple steric block of antisense oligonucleotides, truly catalytic inactivation of miRNA offers more effective, irreversible, and persistent suppression of many copy target sequences. miRNase design can be readily adapted to target other pathogenic microRNAs overexpressed in many disease states.

Exosomal miRNA in chemoresistance, immune evasion, metastasis and progression of cancer

In the treatment of cancer, there are three significant limitations causing high mortality and recurrence rates among cancer patients. First, the escape of tumor cells from the immune system; second, the development of multi-drug resistance (MDR) to chemotherapeutic drugs; and, third, the noxious metastases of cancer cells. Exosomes are vesicular cargos involved in the transportation of miRNA, mRNA and proteins from one cell to another cell. This review details the current understanding of the exosomal transmission of miRNA and crosstalk with the downstream consequences, ultimately leading to the progression and metastasis of cancer. Further, this review also discusses how exosomal miRNA can provide promising novel targets for the treatment and detection of cancer.

Targeted Regulation of miR-26a on PTEN to Affect Proliferation and Apoptosis of Prostate Cancer Cells

Objective: PI3K/AKT signal pathway is important for negative regulation of FoxO3a/p27Kip1, maintaining cell survival and inhibiting apoptosis. Phosphatase and tensin homology deleted on chromosome 10 (PTEN) gene negatively regulates PI3K/AKT signal pathway. It's downregulation is correlated with prostate cancer (PC) pathogenesis. Previous study showed significantly elevated miR-26a expression in PC tissues, indicating its tumor facilitating role in PC. Bioinformatics analysis revealed targeted relationship between miR-26a and 3'-UTR of PTEN mRNA. This study investigated if miR-26a and PTEN dysregulation played a role in proliferation and apoptosis of PC-3 cells. Materials and Methods: PC tumor tissues were collected along with benign prostate hyperplasia samples. Expression of miR-26a and PTEN was detected. The targeted relationship between miR-26a and PTEN was analyzed by dual-luciferase reporter gene assay. In vitro-cultured PC-3 cells were treated with miR-26a inhibitor and/or pIRES2-PTEN. Flow cytometry was employed to detect cell apoptosis, cycle, and Ki-67 expression. Expression of miR-26a and PTEN was analyzed. Western blot was employed to detect protein levels of p-AKT, p-FoxO3a, and p27Kip1. Results: PC tissues had elevated miR-26a expression and lower PTEN expression compared with benign hyperplasia. miR-26a targeted and inhibited PTEN expression. Transfection of miR-26a inhibitor and/or overexpression of PTEN significantly decreased phosphorylation activity of AKT and FoxO3a, enhanced p27Kip1 expression, cell apoptosis, weakened proliferation ability, and arrested cell cycle at G0/G1 phase. Conclusions: PC tissue had higher miR-26a and lower PTEN expressions. miR-26a targeted and inhibited PTEN, potentiated phosphorylation activity of AKT and FoxO3a, downregulated p27Kip1 expression, decreased cell apoptosis, and facilitated proliferation.

Effect of microRNA-27a-5p on apoptosis and inflammatory response of pancreatic acinar cells in acute pancreatitis by targeting PTEN

To investigate the apoptosis and inflammatory response of microRNA-27a-5p (miR-27a-5p) in pancreatic acinar cells of acute pancreatitis (AP) and its related mechanisms. Rat pancreatic acinar cell line AR42J was treated with caerulein (10nmol/L) to construct an acute pancreatitis cell model. Quantitative real-time polymerase chain reaction was performed to measure the expression of miR-27a-5p; The miR-27a-5p mimic was transfected into cell, and the apoptosis rate of the cells was detected by flow cytometry; The levels of TNF-α, IL-1, and IL-6 in the culture supernatant were determined by enzyme-linked immunosorbent assay; TargetScans database predicted and dual luciferase reporter gene assay verified the relationship between miR-27a-5p and the phosphatase and tensin homolog deleted on chromosome 10 (PTEN); The recovery experiment explored the apoptosis and the effects of inflammatory responses. The expression of miR-27a-5p decreased gradually (P < 0.05) and the expression of PTEN increased gradually (P < 0.05) with the prolongation of acting time. Upregulation of miR-27a-5p significantly promoted cell apoptosis (P < 0.05) and inhibited inflammatory response (P < 0.05); The TargetScans database predicted that the 3'UTR of PTEN contains a base complementary to the miR-27a-5p seed region. Cotransfection of wild-type vector (PTEN-WT) with miR-27a-5p mimic or miR-27a-5p inhibitor significantly affected the relative activity of luciferase (P < 0.05), and no significant impact was observed in mutant PTEN-MUT. Compared with miR-27a-5p + pcDNA group, transfection of miR-27a-5p mimic and pcDNA-PTEN significantly increased the expression of PTEN (P < 0.05), decreased the apoptotic rate (P < 0.05), and increased the inflammatory response (P < 0.05). miR-27a-5p induced apoptosis and inhibited the inflammatory response of pancreatic acinar cells in AP by targeting PTEN.

Effect of miR-301a/PTEN pathway on the proliferation and apoptosis of cervical cancer

The aim of this study was to evaluate the effect of the miR-301a/PTEN pathway in cervical cancer. miR-301a and PTEN expression were measured by quantitative real-time PCR (qRT-PCR) in tissues samples and HeLa cells. PTEN protein level was determined by Western blotting. Dual reporter luciferase assay was performed to validate PTEN as a direct target of miR-301a. The gain- and loss-of function assay was performed by miR-301a overexpression and silencing. Cell proliferation was monitored by cell counting Kit-8 (CCK-8). Cell apoptosis was quantitated by flow cytometry. SPSS was used to analyze the significant difference in the treatments. miR-301a demonstrated a significantly higher expression in cervical carcinoma tissues compared with the paired non-carcinoma tissues ( n = 12), while PTEN expression was found to be significantly lower in cervical carcinoma tissues than their paired non-carcinoma tissues ( n = 12). In addition, PTEN was identified as the direct target of miR-301a. Moreover, overexpression of miR-301a significantly promoted HeLa cells proliferation and anti-apoptosis which had a reverse pattern after PTEN overexpression. Our results confirm PTEN as a direct target of miR-301a in HeLa cells and suggest that miR-301a/PTEN pathway contributes to the development and progression of cervical cancer.

RETRACTED: Gastrodin protects rat cardiomyocytes H9c2 from hypoxia-induced injury by up-regulation of microRNA-21

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Author. The journal contacted the authors for their response to the following remark from Dr Elisabeth Bik regarding this paper: ‘This paper belongs to a set of over 400 papers (as per February 2020) that share very similar Western blots with tadpole-like shaped bands, the same background pattern, and striking similarities in title structures, paper layout, bar graph design, and - in a subset - flow cytometry panels. Despite these similarities, these papers are authored by researchers from different departments and institutes, with almost no overlap in authors’. The authors failed to respond to this directly but instead requested the journal to retract the paper on the basis that the data were not represented accurately and new results have shown inconsistency with what has been reported in this paper. The authors apologise for any misconceptions that this paper may have resulted in.

Hypoxic non-small-cell lung cancer cell-derived exosomal miR-21 promotes resistance of normoxic cell to cisplatin

Purpose

To explore the effects of hypoxic non-small-cell lung cancer (NSCLC)-derived exosomes on NSCLC resistance to cisplatin.

Materials and methods

Exosomes were isolated by differential centrifugation and characterized by transmission electron microscope and Western blotting. Quantitative real-time PCR was used to measure miR-21 levels. MTT assays and colony formation assays were performed to investigate the effects of hypoxia-induced exosomes on cisplatin resistance.

Results

Hypoxic NSCLC cell-derived exosomes facilitate normoxic cell resistance to cisplatin. In addition, hypoxia enhanced the miR-21 expression in NSCLC cells and cell-derived exosomes. Interestingly, changes in miR-21 levels in the hypoxia-induced exosomes affected the sensitivity of recipient cells to cisplatin. Mechanically, exosomal miR-21 promoted cisplatin resistance by downregulating phosphatase and tensin homolog (PTEN). The expression of miR-21 in tumor cell lines and clinical NSCLC tumor samples was positively correlated with hypoxia-inducible factor-1α and negatively correlated with PTEN. Moreover, high miR-21 expression was associated with shorter median survival period in patients undergoing pharmacotherapy, but no association was observed in patients who were not under pharmacotherapy.

Conclusion

Exosomal miR-21 derived from hypoxic NSCLC cells may promote cisplatin resistance, which indicates that exosomal miR-21 might be a potential biomarker and therapeutic target to address NSCLC chemoresistance.

Curcumol inhibits colorectal cancer proliferation by targeting miR-21 and modulated PTEN/PI3K/Akt pathways

AIMS

The purpose of this study was to demonstrate how curcumol affected the expression of miR-21 and whether its effects on miR-21 was associated with the activation of PTEN/PI3K/Akt pathways in CRC cells.

MAIN METHODS

MTT and xenograft assay were used to examine how curcumol inhibits colorectal cancer (CRC) cells' growth. Q-PCR and western blot analysis were employed to test the role of miR-21 in the inhibition of curcumol on proliferation and PTEN/PI3K/Akt pathways of CRC cells.

KEY FINDINGS

We found that curcumol effectively inhibited CRC cells from proliferating via the PTEN/PI3K/Akt pathways and reduced expression of miR-21 both in vitro and in vivo. miR-21 mimics were found to decrease the protein level of PTEN and increase the expression of PI3K, phospho-Akt (p-Akt) and NF-κB, while miR-21 sponge (miR-21-SP) enhanced the expression of PTEN and reduced the activity of PI3K, Akt and NF-κB. Furthermore, miR-21-SP strengthened the role of curcumol in up-regulating PTEN and inhibiting PI3K/Akt pathways, but miR-21 reversed the effect of curcumol on the PTEN/PI3K/Akt pathways.

SIGNIFICANCE

Our research demonstrated that curcumol reduced the proliferation of CRC cells through PTEN/PI3K/Akt by targeting miR-21 and miR-21 could be a target molecule of curcumol for CRC treatment.

Targeting MicroRNA-21 Suppresses Gastric Cancer Cell Proliferation and Migration via PTEN/Akt Signaling Axis

MicroRNA plays a pivotal role in various human cancers, especially in human gastric cancer. In the present study, we evaluated the effect of microRNA-21 (miR-21) on the gastric cancer cell proliferation, migration, apoptosis and the related signaling cascades. Here, we showed that down-regulation of miR-21 markedly reduced gastric cancer cell proliferation (AGS and NCI-N87 cells) in a time dependent manner. Moreover, our findings revealed that silencing miR-21 dramatically blocked gastric cancer cell migration and movement, which might be related to down-regulation of vimentin expression. We also found that down-regulation of miR-21 promoted cell apoptosis and repressed cell cycle progression. Further investigation showed that down-regulation of miR-21 significantly increased phosphatase and tensin homolog (PTEN) protein expression level, but not transcription level (mRNA level), which in turn decreased Akt phosphorylation at Thr308 and Ser473. Collectively, our results uncover that miR-21 targets PTEN/Akt signaling pathway and regulates cell proliferation, migration and apoptosis in human gastric cancer cells. Our findings may provide a therapeutic target for treatment of human gastric cancer.

Mesyl phosphoramidate antisense oligonucleotides as an alternative to phosphorothioates with improved biochemical and biological properties

Forty years of research have shown that antisense oligonucleotides have great potential to target mRNAs of disease-associated genes and noncoding RNAs. Among the vast number of oligonucleotide backbone modifications, phosphorothioate modification is the most widely used in research and the clinic. However, along with their merits are notable drawbacks of phosphorothioate oligonucleotides, including decreased binding affinity to RNA, reduced specificity, and increased toxicity. Here we report the synthesis and in vitro evaluation of the DNA analog mesyl phosphoramidate oligonucleotide. This oligonucleotide type recruits RNase H and shows significant advantages over phosphorothioate in RNA affinity, nuclease stability, and specificity in inhibiting key processes of carcinogenesis. Thus, mesyl phosphoramidate oligonucleotides may be an attractive alternative to phosphorothioates.

Here we describe a DNA analog in which the mesyl (methanesulfonyl) phosphoramidate group is substituted for the natural phosphodiester group at each internucleotidic position. The oligomers show significant advantages over the often-used DNA phosphorothioates in RNA-binding affinity, nuclease stability, and specificity of their antisense action, which involves activation of cellular RNase H enzyme for hybridization-directed RNA cleavage. Biological activity of the oligonucleotide analog was demonstrated with respect to pro-oncogenic miR-21. A 22-nt anti–miR-21 mesyl phosphoramidate oligodeoxynucleotide specifically decreased the miR-21 level in melanoma B16 cells, induced apoptosis, reduced proliferation, and impeded migration of tumor cells, showing superiority over isosequential phosphorothioate oligodeoxynucleotide in the specificity of its biological effect. Lower overall toxicity compared with phosphorothioate and more efficient activation of RNase H are the key advantages of mesyl phosphoramidate oligonucleotides, which may represent a promising group of antisense therapeutic agents.

MiR-139-5p regulates VEGFR and downstream signaling pathways to inhibit the development of esophageal cancer

BACKGROUND

MiR-139-5p plays a significant role in tumorigenesis, metastasis and recurrence, suggesting that it may potentially be used as a promising biomarker for esophageal cancer diagnosis, prognosis and therapy. This study aimed to investigate the role and the mechanism of miRNA-139-5p in esophageal cancer.

METHODS

This study included 11 patients from an area with a high incidence of esophageal cancer. The expression levels of miRNA-139-5p in esophageal cancer tissues and para-carcinoma tissues of 11 patients were measured. We examined the expression of miR-139-5p in serum obtained from 92 consecutive patients from Cixian, which is a region in Hebei Province with a high rate of histologically confirmed esophageal cancer. The expression of miR-139-5p in esophageal cancer cell lines was detected. In the KYSE150 cell line with the lowest expression level of miR-139-5p, we transfected a plasmid to upregulate the expression level and examined the role of miR-139-5p in esophageal squamous cell carcinoma proliferation, migration and invasion. We conducted a gene profiling study using miR-139-5p cell lines to detect the expression of significant genes related to tumor progression, including cyclinD1, E-cadherin and VEGFR-1. We then constructed luciferase reporters containing miR-139-5p, which contained wild-type (WT) or mutated-type (Mut) VEGFR-1 binding sites to investigate the target.

RESULTS

MiRNA-139-5p expression levels in esophageal cancer tissues from 11 patients were significantly higher than those in para-carcinoma tissues. MiR-139-5p expression in the serum of 92 patients with esophageal cancer was associated with gender (P = 0.039) and TNM stage (P = 0.015). Factors that were not correlated with miR-139-5p expression were age (P = 0.293), smoking history (P = 0.397), length of tumor (P = 0.309), width of tumor (P = 0.296), depth of tumor (P = 0.724), lymphoma metastasis (P = 0.531) and postoperative therapy (P = 0.884). MiR-139-5p (P = 0.013) correlated significantly with observed survival rates. The lymphoma metastasis (P = 0.005) and TNM stage (P = 0.000) were significantly associated with observed survival rates. However, no significant relationships were found between the miR-139-5p and patient characteristics including gender, age, smoking history, tumor size and postoperative therapy. In the KYSE150 cell line, the expression level of miR-139-5p was the lowest. We transfected a plasmid to upregulate the expression level and found that the cell proliferation, metastasis and invasion abilities decreased. Upregulation of miR-139-5p inhibited the expression of Cyclin D1 and VEGFR-1 and increased the expression of E-cadherin. For further confirmation, we constructed luciferase reporters containing miR-139-5p, which contained wild-type (WT) or mutated-type (Mut) VEGFR-1 binding sites for target investigation. The results show that the corresponding VEGFR-1-Mut construct no longer suppressed miR-139-5p.

CONCLUSIONS

MiR-139-5p may be a novel therapeutic target and prognostic biomarker of esophageal cancer.

Network pharmacology-based prediction of the active ingredients, potential targets, and signaling pathways in compound Lian-Ge granules for treatment of diabetes

AIMS

Compound Lian-Ge granules (CLGGs) is a traditional Chinese medicine preparation with good hypoglycemic effect and health function. This study was to predict its active ingredients, potential targets, signaling pathways, and investigate its mechanism of "ingredient-targets-pathways."

METHODS

Pharmacodynamics studies on diabetic rats showed that CLGGs had an obvious hypoglycemic effect. On this basis, 27 hypoglycemic active ingredients were screened out. Their targets were confirmed by comparing with these hypoglycemic targets in PharmMapper and DrugBank databases via reversed pharmacophore matching approach. The relationships between ingredients and targets were revealed by comparing data in the String database. A network of "ingredient-target-passageway" was constructed.

RESULTS

Studies showed that CLGGs had 24 active ingredients, ie, berberine, puerarin, danshinolic acid A, and sinigrin, etc. These ingredients involved nine targets, ie, insulin-like growth factor 1 receptor, insulin-degrading enzyme, ɑ-amylase, and so on, and 111 metabolic pathways, eg, hypoxia-inducible factor 1 signaling pathway, PI3K-Akt signaling pathway, mammalian target of rapamycin signaling pathway, and FoxO signaling pathway.

CONCLUSION

Using network pharmacology methods, this study predicted the hypoglycemic active ingredients in CLGGs and revealed their targets, and provided a clue for further exploration of the hypoglycemic mechanism of CLGGs.

MicroRNA-195: a review of its role in cancers

MicroRNAs (miRNAs) are small and highly conserved noncoding RNAs that regulate gene expression at the posttranscriptional level by binding to the 3′-UTR of target mRNAs. Recently, increasing evidence has highlighted their profound roles in various pathological processes, including human cancers. Deregulated miRNAs function as either oncogenes or tumor suppressor genes in multiple cancer types. Among them, miR-195 has been reported to significantly impact oncogenicity in various neoplasms by binding to critical genes and signaling pathways, enhancing or inhibiting the progression of cancers. In this review, we focus on the expression of miR-195 in regulatory mechanisms and tumor biological processes and discuss the future potential therapeutic implications of diverse types of human malignancies.

Circulating serum oncologic miRNA in pediatric juvenile pilocytic astrocytoma patients predicts mural nodule volume

BACKGROUND

Juvenile pilocytic astrocytomas represent the largest group of pediatric brain tumors. The ideal management for these tumors is early, total surgical resection. To detect and track treatment response, a screening tool is needed to identify patients for surgical evaluation and assess the quality of treatment. The identification of aberrant miRNA profiles in the sera of juvenile pilocytic astrocytoma patients could provide such a screening tool.

METHODS

The authors reviewed the serum profiles of 84 oncologically relevant miRNAs in pediatric juvenile pilocytic astrocytoma patients via qPCR screening.

RESULTS

miR-21, miR-15b, miR-23a, and miR-146b were significantly elevated in the sera of JPA patients as compared to non-oncologic controls, oncologic controls, and post-JPA resection samples (p < 0.001, 0.022, 0.034, 0.044). miR-21 had the highest AUC on ROC analysis (AUC > 0.99, sensitivity 75%, specificity 100%). All four miRNAs also correlated well with tumor mural nodule size, though they only poorly correlated with total tumor size, including cystic components (Spearman's R²: miR-21 91.7 vs 6.9%, miR-15b 86.3 vs 23.1%, miR-23a 85.8 vs 23.0%, miR-146b 59.8 vs 11.9%).

CONCLUSION

In this small pilot study, pediatric juvenile pilocytic astrocytoma patients had significant elevations in serum miR-21, miR-15b, miR-23a, and miR-146b levels that do not appear to be driven by hydrocephalus or local distortion of the intracranial contents. These alterations correlate with solid tumor component volume and reverse with complete tumor resection, suggesting that this serum miRNA profile may delineate biomarkers for screening and tracking juvenile pilocytic astrocytoma patients. Additional studies, with a larger cohort, are needed to verify these results.

MiR-374b Promotes Proliferation and Inhibits Apoptosis of Human GIST Cells by Inhibiting PTEN through Activation of the PI3K/Akt Pathway

Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. In order to investigate a new treatment fot GIST, we hypothesized the effect of miR-374b targeting PTEN gene-mediated PI3K/Akt signal transduction pathway on proliferation and apoptosis of human gastrointestinal stromal tumor (GIST) cells. We obtained GIST tissues and adjacent normal tissues from 143 patients with GIST to measure the levels of miR-374b, PTEN, PI3K, Akt, caspase9, Bax, MMP2, MMP9, ki67, PCNA, P53 and cyclinD1. Finally, cell viability, cell cycle and apoptosis were detected. According to the KFGG analysis of DEGs, PTEN was involved in a variety of signaling pathways and miRs were associated with cancer development. The results showed that MiR-374b was highly expressed, while PTEN was downregulated in the GIST tissues. The levels of miR-374b, PI3K, AKT and PTEN were related to tumor diameter and pathological stage. Additionally, miR-374b increased the mRNA and protein levels of PI3K, Akt, MMP2, MMP9, P53 and cyclinD1, suggesting that miR-374b activates PI3K/Akt signaling pathway in GIST-T1 cells. Moreover, MiR-374b promoted cell viability, migration, invasion, and cell cycle entry, and inhibited apoptosis in GIST cells. Taken together, the results indicated that miR-374b promotes viability and inhibits apoptosis of human GIST cells by targeting PTEN gene through the PI3K/Akt signaling pathway. Thus, this study provides a new potential target for GIST treatment.

The CADM2/Akt pathway is involved in the inhibitory effect of miR-21-5p downregulation on proliferation and apoptosis in esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC), the main subtype of esophageal cancer, is the eighth most common cancer worldwide. Cell adhesion molecule 2 (CADM2) has been reported to be a tumor suppressor and is usually downregulated in several cancers. However, the role of CADM2 in ESCC remains unknown. The aim of the present study was to evaluate the potential role and underlying action mechanism of CADM2 in ESCC. Herein, we found that CADM2 was low-expressed in ESCC tissues and cell lines. CADM2 overexpression inhibited proliferation and induced apoptosis of ESCC cells. Moreover, CADM2 overexpression also suppressed the Akt signaling pathway in ESCC cells. MiR-21-5p down-regulation inhibited cell proliferation and induced cell apoptosis, while CADM2 knockdown attenuated the effect of anti-miR-21-5p. The expression of p-Akt was decreased in the cells transfected with anti-miR-21. However, the expression of p-Akt was increased in the cells co-transfected with anti-miR-21-5p and si-CADM2 compared with that in anti-miR-21-5p-transfecting cells. In summary, the CADM2/Akt pathway is involved in the inhibitory effect of miR-21-5p downregulation on proliferation and apoptosis in ESCC cells. These findings indicated that the miR-21-5p/CADM2/Akt axis might be a new approach for the treatment of ESCC.

Inhibition of miR-21-5p suppresses high glucose-induced proliferation and angiogenesis of human retinal microvascular endothelial cells by the regulation of AKT and ERK pathways via maspin

The aim of the present study is to investigate the role of miR-21-5p in angiogenesis of human retinal microvascular endothelial cells (HRMECs). HRMECs were incubated with 5 mM glucose, 30 mM glucose or 30 mM mannitol for 24 h, 48 h or 72 h. Then, HRMECs exposed to 30 mM glucose were transfected with miR-21-5p inhibitor. We found that high glucose increased the expression of miR-21-5p, VEGF, VEGFR2 and cell proliferation activity. Inhibition of miR-21-5p reduced high glucose-induced proliferation, migration, tube formation of HRMECs, and reversed the decreased expression of maspin as well as the abnormal activation of PI3K/AKT and ERK pathways. Down-regulation of maspin by siRNA significantly increased the activities of PI3K/AKT and ERK pathways. In conclusion, inhibition of miR-21-5p could suppress high glucose-induced proliferation and angiogenesis of HRMECs, and these effects may partly dependent on the regulation of PI3K/AKT and ERK pathways via its target protein maspin.

miRNA regulation of innate immunity

MicroRNAs (miRNAs) are small noncoding RNA and are pivotal posttranscriptional regulators of both innate and adaptive immunity. They act by regulating the expression of multiple immune genes, thus, are the important elements to the complex immune regulatory network. Deregulated expression of specific miRNAs can lead to potential autoimmunity, immune tolerance, hyper-inflammatory phenotype, and cancer initiation and progression. In this review, we discuss the contributory pathways and mechanisms by which several miRNAs influence the development of innate immunity and fine-tune immune response. Moreover, we discuss the consequence of deregulated miRNAs and their pathogenic implications.

Downregulation of microRNA-21 inhibited radiation-resistance of esophageal squamous cell carcinoma

Background

MicroRNA-21 (miR-21) was previously reported being dysregulated in many kinds of cancer including esophageal squamous cell carcinoma (ESCC). In the present study, we aimed to investigate the role of miR-21 in ESCC, especially in its effects on radiation-sensitivity of ESCC.

Methods

Expression of miR-21 was detected in 63 pairs ESCC tumor and adjacent non-tumoral tissues using qRT-PCR, correlation between miR-21 and clinicopathological feature of ESCC was analyzed. The role of miR-21 in the proliferation, cell cycle and apoptosis of ESCC cells during irradiation were studied.

Results

MicroRNA-21 expression was significantly increased in ESCC tumor tissues. Expression of miR-21 was positively associated with advanced clinical stage. Under irradiation, overexpression of miR-21 increased cell proliferation and cells in S phase, and inhibited cell apoptosis of ESCC cells. In contrast, knockdown of miR-21 had an opposite effect.

Conclusions

Downregulation of miR-21 inhibited the radiation-resistance of ESCC, whereas overexpression of miR-21 increased the radiation-resistance. MiR-21 is a potential novel target for developing specific treatment interventions in ESCC in future.

Blood and lung microRNAs as biomarkers of pulmonary tumorigenesis in cigarette smoke-exposed mice

Cigarette smoke (CS) is known to dysregulate microRNA expression profiles in the lungs of mice, rats, and humans, thereby modulating several pathways involved in lung carcinogenesis and other CS-related diseases. We designed a study aimed at evaluating (a) the expression of 1135 microRNAs in the lung of Swiss H mice exposed to mainstream CS during the first 4 months of life and thereafter kept in filtered air for an additional 3.5 months, (b) the relationship between lung microRNA profiles and histopathological alterations in the lung, (c) intergender differences in microRNA expression, and (d) the comparison with microRNA profiles in blood serum. CS caused multiple histopathological alterations in the lung, which were almost absent in sham-exposed mice. An extensive microRNA dysregulation was detected in the lung of CS-exposed mice. Modulation of microRNA profiles was specifically related to the histopathological picture, no effect being detected in lung fragments with non-neoplastic lung diseases (emphysema or alveolar epithelial hyperplasia), whereas a close association occurred with the presence and multiplicity of preneoplastic lesions (microadenomas) and benign lung tumors (adenomas). Three microRNAs regulating estrogen and HER2-dependent mechanisms were modulated in the lung of adenoma-bearing female mice. Blood microRNAs were also modulated in mice affected by early neoplastic lesions. However, there was a poor association between lung microRNAs and circulating microRNAs, which can be ascribed to an impaired release of mature microRNAs from the damaged lung. Studies in progress are evaluating the feasibility of analyzing blood microRNAs as a molecular tool for lung cancer secondary prevention.

Generation of PTEN knockout bone marrow mesenchymal stem cell lines by CRISPR/Cas9-mediated genome editing

The tumor suppressor PTEN is involved in the regulation of cell proliferation, lineage determination, motility, adhesion and apoptosis. Loss of PTEN in the bone mesenchymal stem cells (BMSCs) was shown to change their function in the repair tissue. So far, the CRISPR/Cas9 system has been proven extremely simple and flexible. Using this system to manipulate PTEN gene editing could produce the PTEN-Knocking-out (PTEN-KO) strain. We knocked out PTEN in MSCs and validated the expression by PCR and Western blot. To clarify the changes in proliferation, CCK-8 assay was applied. In support, living cell proportion was assessed by Trypan blue staining. For osteogenic and adipogenic induction, cells were cultured in different media for 2 weeks. Oil red staining and alizarin red staining were performed for assessment of osteogenic or adipogenic differentiation. The expression of Id4, Runx2, ALP and PPARγ was examined by qPCR and immunocytochemistry staining. The PTEN-KO strain was identified by sequencing. The PTEN-KO cells had an increased cell viability and higher survival compared with the wild type. However, decreased expression of Runx2 and PPARγ was found in the PTEN loss strain after induction, and consistently decreased osteogenic or adipogenic differentiation was observed by alizarin and oil red staining. Together, PTEN-KO strain showed an increased proliferation capability but decreased multi-directional differentiation potential. When BMSCs serve as seed cells for tissue engineering, the PTEN gene may be used as an indicator.

Pterostilbene increases PTEN expression through the targeted downregulation of microRNA-19a in hepatocellular carcinoma

Pterostilbene (Pter) is reported to exhibit an anticancer effect in hepatocellular carcinoma (HCC). In order to explore the anticancer mechanism in HCC cells, the present study aimed to investigate whether pterostilbene (Pter) may increase phosphatase and tensin homolog (PTEN) expression through targeted downregulation of microRNA (miRNA/miR)-19a in hepatocellular carcinoma (HCC). The proliferation, apoptosis and cell cycle was analyzed in the SMMC-7721 HCC cell line by MTT assays and flow cytometry methods. Cells were divided into five treatment groups: Pter treatment, miR-19a inhibitor transfection, Pter + miR-19a inhibitor, negative control transfection and blank control. The expression of miR-19a and PTEN was detected by reverse transcription-quantitative polymerase chain reaction and western blot analysis following treatment. Furthermore, a luciferase reporter gene assay was performed to determine whether the PTEN gene was a direct target of miR-19a. The results demonstrated that Pter treatment or miR-19a inhibitor transfection downregulated miR-19a and induced PTEN/Akt pathway regulation, which led to proliferation inhibition, cell cycle arrest in the S phase, increased apoptosis and reduced cell invasion. These results indicated that Pter may increase PTEN expression through the direct downregulation of miR-19a in HCC. Therefore, miR-19a may have potential as a novel molecular marker for HCC and Pter may be a promising clinical target with the potential to be developed as a HCC therapy.

Honokiol suppresses proliferation and induces apoptosis via regulation of the miR‑21/PTEN/PI3K/AKT signaling pathway in human osteosarcoma cells

Honokiol (HNK) is a small biphenolic compound, which exerts antineoplastic effects in various types of cancer. However, the mechanism underlying the antitumor effects of HNK in osteosarcoma (OS) cells is not yet fully understood. Emerging evidence has indicated that microRNAs (miRNAs/miRs) serve key roles in numerous pathological processes, including cancer. It has previously been reported that Chinese medicinal herbs harbor anticancer properties via modulating miRNA expression. Therefore, the present study aimed to determine whether HNK could suppress OS cell growth by regulating miRNA expression. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometric analysis were used to evaluate the cell proliferation and apoptosis in human OS cells after treatment with HNK, respectively. The results demonstrated that HNK inhibits proliferation and induces apoptosis of human OS cells in a dose-dependent manner. Furthermore, HNK-induced apoptosis was characterized by upregulation of proapoptotic proteins, including cleaved-caspase-3, cleaved-poly (ADP-ribose) polymerase and B-cell lymphoma 2 (Bcl-2)-associated X protein, and downregulation of the anti-apoptotic protein Bcl-2. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) verified that HNK was able to induce aberrant expression of miRNAs in human OS cells, and miR-21 was one of the miRNAs that was most significantly downregulated. To further investigate miR-21 function, the present study validated that HNK reduces miR-21 levels in a dose-dependent manner. In addition, restoration of miR-21 expression abrogated the suppressive effects of HNK on OS cells. Luciferase assay and western blot analysis identified that miR-21 inhibits the expression of phosphatase and tensin homolog (PTEN) by directly targeting its 3′-UTR. Notably, HNK was able to suppress the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway; however, it was reactivated by miR-21 overexpression. Taken together, these data indicated that HNK may inhibit proliferation and induce apoptosis of human OS cells by modulating the miR-21/PTEN/PI3K/AKT signaling pathway. Therefore, miR-21 may be considered a potential therapeutic target for the treatment of osteosarcoma with HNK.

Long non-coding RNA CASC2 enhanced cisplatin-induced viability inhibition of non-small cell lung cancer cells by regulating the PTEN/PI3K/Akt pathway through down-regulation of miR-18a and miR-21

Long non-coding RNA cancer susceptibility candidate 2 (lncRNA CASC2) is a tumor suppressor and has been proved to contribute to chemotherapy efficacy. However, the effect of CASC2 on cisplatin cytotoxicity in non-small cell lung cancer (NSCLC) is unclear. The present study aimed to investigate the role of CASC2 in regulating cisplatin cytotoxicity in NSCLC cells. Herein, we found that CASC2 was low-expressed, while miR-18a and miR-21 were over-expressed in NSCLC cell lines. CASC2 enhanced the inhibition effect of cisplatin on cell viability. Down-regulation of miR-18a and miR-21 exhibited the similar effect to CASC2 and mimics of miR-18a and miR-21 displayed the opposite effect to CASC2. MiR-18a and miR-21 were two targets of CASC2 in NSCLC. PTEN was found to be a target of miR-18a and miR-21 in NSCLC. CASC2 overexpression increased PTEN expression level and reduced the ratio of p-Akt/Akt. MiR-18a or miR-21 mimics attenuated the effect of CASC2 overexpression on the PTEN expression and ratio of p-Akt/Akt. The results suggested that CASC2 enhanced cisplatin-induced viability inhibition of NSCLC cells via PTEN/PI3K/Akt pathway through suppressing miR-18a and miR-21 expression.

Long non-coding RNA cancer susceptibility candidate 2 (lncRNA CASC2) is a tumor suppressor and has been proved to contribute to chemotherapy efficacy.

Metformin inhibits HaCaT cell viability via the miR-21/PTEN/Akt signaling pathway

Substantial preclinical evidence has indicated out a direct anti‑proliferation effect of metformin on various solid tumors; however, further and more detailed exploration into its molecular mechanism remains to be performed. The present study aimed to investigate the effect of metformin on cell viability and its underlying mechanism, in the cultured human skin keratinocyte cell line, HaCaT. In addition, it aimed to clarify the role of the microRNA-21(miR-21)/phosphatase and tensin homolog (PTEN)/AKT serine/threonine kinase 1 (Akt) signaling pathway, which has been hypothesized to be involved in the molecular mechanism of this drug. Cell Counting Kit‑8 assays were used to assess the impact of metformin on cell viability; reverse transcription‑quantitative polymerase chain reaction was used to quantify the expression of miR‑21; western blotting was used to monitor the expression level of PTEN and Akt proteins. In addition, miR‑21 expression levels were artificially manipulated in HaCaT cells using a miR‑21 inhibitor in order to observe the subsequent expression changes of miR‑21 targets and alterations in cell viability. The results indicated that metformin suppressed HaCaT cell growth in a dose‑ and time‑dependent manner (P<0.05). Metformin treatment downregulated miR‑21 expression (t=‑8.903, P<0.05). Following transfection with the miR‑21 inhibitor, HaCaT cell growth was significantly slower than in the control groups (P<0.05). In addition, reduced miR‑21 levels results in significantly increased PTEN protein expression levels and reduced Akt protein expression levels compared with control (P<0.05). Metformin was, therefore, concluded to inhibit HaCaT cell growth in a time‑and dose‑dependent manner, and the miR‑21/PTEN/Akt signaling pathway may serve a crucial role in the molecular mechanism of metformin's effect on HaCaT cells. Therefore the present study presents an advanced insight into the potential inhibitory effect of metformin on tumor cells.

A Genetic Variant in miR-124 Decreased the Susceptibility to Esophageal Squamous Cell Carcinoma in a Chinese Kazakh Population

AIMS

Esophageal squamous cell carcinoma (ESCC) is characterized by high prevalence and mortality worldwide, and it is very highly prevalent in China. ESCC is caused by various factors, including microRNAs (miRNAs) whose expression have been shown to play a major role in tumor generation. Single nucleotide polymorphisms (SNPs) in miRNAs could affect susceptibility to numerous cancers. This study aimed to evaluate the relationship between SNPs in miR-124 and ESCC risk in the Chinese Kazakh population.

METHODS

A total of 239 Chinese Kazakh patients with ESCC and 227 healthy Chinese Kazakh individuals were recruited in this study. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to analyze the miR-124 rs531564 genotype.

RESULTS

Allele G of the miR-124 rs531564 polymorphism significantly reduced the risk of ESCC in the Chinese Kazakh population [odds ratio (OR) = 0.711; 95% confidence interval (CI): 0.508-0.996; p = 0.047]. The dominant model indicated that the CG+GG genotypes were associated with significantly decreased ESCC risk compared to the CC genotype (adjusted OR = 0.586; 95% CI: 0.396-0.867; p = 0.007). Stratification analyses showed that compared with the CC genotype, the CG and CG+GG genotypes manifested reduced ESCC risks in the female group [CG vs. CC: OR = 0.472; 95% CI: 0.255-0.872; p = 0.016; (CG+GG) vs. CC: OR = 0.472; 95% CI: 0.255-0.872; p = 0.016] and the age group of <57 years old [CG vs. CC: OR = 0.456; 95% CI: 0.258-0.806; p = 0.006; (CG+GG) vs. CC: OR = 0.456; 95%CI: 0.258-0.806; p = 0.006]. The miR-124 rs531564 polymorphism showed no significant association with histological stage, lymph node metastasis, depth of invasion, or tumor/node/metastasis stage.

CONCLUSIONS

Our findings are the first to be reported that the miR-124 rs531564 polymorphism decreased ESCC risk in the Chinese Kazakh population.

Inhibition of miRNA-21 attenuates the proliferation and metastasis of human osteosarcoma by upregulating PTEN

The present study aimed to investigate the expression of micro (mi)RNA-21 in osteosarcoma cells, and its role in inhibiting the invasion and metastasis of osteosarcoma. Human osteosarcoma MG-63 cells and osteoblast hFOB1.19 cells were used to compare the expression of miRNA-21 using reverse transcription-quantitative polymerase chain reaction analysis. A miRNA-21 mimic or inhibitor were transfected into the MG-63 cells to upregulate and downregulate the expression of miRNA-21, respectively. The present study investigated the proliferation and invasion of transfected MG-63 cells using MTT and Transwell assays. Western blot analyses were used to investigate the regulation of important proteins in the phosphatase and tensin homolog/phosphoinositide 3-kinase/RAC-α serine/threonine-protein kinase (PTEN/PI3K/AKT) signaling pathway. Compared with hFOB1.19 cells, miRNA-21 expression was significantly upregulated in the MG-63 cells (P<0.01), which lead to increased proliferation. Downregulating miRNA-21 expression reduced the proliferation of MG-63 cells compared with hFOB1.19 cells. Invasion assays and western blot analyses revealed that the overexpression of miRNA-21 significantly enhanced the invasion ability of MG-63 cells and the expression of phosphorylated (p-)AKT, while downregulation of miRNA-21 expression reduced the protein level of AKT and p-AKT. In the MG-63 cells, miRNA-21 upregulation significantly inhibited the protein level of PTEN, resulting in significantly increased AKT and PI3K protein levels (P<0.01). In conclusion, the results of the present study indicate that the expression of miRNA-21, PI3K and AKT is increased in the osteosarcoma cell line MG-63, which results in reduced expression of PTEN and increased expression of proteins in the PI3K/AKT signaling pathway, and thus increases the aggressiveness of osteosarcoma cells.

Fucoidan elevates surface organic cation transporter 2 expression via upregulation of protein kinase A in uric acid nephropathy

Uric acid nephropathy (UAN) is caused by excessive uric acid, and is a key risk factor for uric acid nephrolithiasis, gouty arthritis, renal diseases and cardiovascular diseases. The present study aimed to evaluate the protective effect of fucoidan, a sulfated polysaccharide component of brown algae, on UAN and to elucidate the underlying molecular mechanism. A rat model of UAN was induced by adenine treatment, and rats were then randomly assigned to control, model or fucoidan treatment groups. Hematoxylin and eosin staining of the kidney tissues of rats with UAN was subjected to conventional morphological evaluation. Cellular infiltrate in the tubules, atrophic glomeruli, tubular ectasia, granuloma hyperplasia focal fibrosis and accumulated urate crystals in the tubules of UAN rat renal tissues were observed. These symptoms of kidney damage were reduced in the fucoidan treatment group. Periodic acid methenamine silver-Masson staining was performed and the results indicated that renal interstitial fibrosis was reduced among renal tissues from the fucoidan treatment group compared with the model group. Terminal deoxynucleotidyl-transferase-mediated dUTP nick end labelling staining revealed a lower proportion of apoptotic nuclei in the kidneys of the fucoidan treatment group compared with the model group. Protein kinase A (PKA) 2β and phosphorylated PKA 2β protein levels were significantly elevated in renal tissues of the fucoidan treatment group compared with the model group (P<0.05 and P<0.01, respectively), suggesting that PKA expression was upregulated by fucoidan. Immunohistochemistry staining of PKA in rat renal tissues demonstrated increased expression of PKA. The surface organic cation transporter 2 (OCT2) level was significantly increased by fucoidan treatment compared with the model group (P<0.01), with no significant change in total OCT2 level. COS-7 cells ectopically expressing OCT2 were established. It was indicated that fucoidan was able to activate PKA and upregulate surface OCT2 in OCT2-expressing COS-7 cells. This further demonstrated that upregulation of surface OCT2 expression in OCT2-expressing cells was induced by PKA upregulation. In conclusion, fucoidan upregulated surface OCT2 expression in renal tissues to alleviate the symptoms of UAN via upregulated expression of PKA.

Association of long non-coding RNA GAS5 and miR-21 levels in CD4+ T cells with clinical features of systemic lupus erythematosus

The present study aimed to assess the expression of growth arrest-specific 5 (GAS5) and microRNA (miR)-21 in systemic lupus erythematosus (SLE), and attempted to explore their association with clinical features. CD4⁺ T cells were isolated from peripheral blood of healthy donors and SLE patients by magnetic-activated cell sorting. GAS5 and miR-21 expression levels in cluster of differentiation (CD)4⁺ T cells were measured by reverse-transcription quantitative polymerase chain reaction. The results revealed that GAS5 and miR-21 levels were significantly elevated in CD4⁺ T cells of patients with SLE compared with those in control subjects (P<0.05). Regarding clinical features, SLE patients with ulceration had higher GAS5 expression levels in CD4⁺ T cells than those without ulceration (P<0.05), and the expression of miR-21 was significantly higher in CD4⁺ T cells of SLE patients with low levels of complement component 3 (C3) than in those with normal levels of complement C3 (P<0.05). In conclusion, GAS5 and miR-21 in CD4⁺ T cells may serve as potential biomarkers for the diagnosis and monitoring of the progression of SLE.

Molecular mechanisms and theranostic potential of miRNAs in drug resistance of gastric cancer

INTRODUCTION

Systemic chemotherapy is a curative approach to inhibit gastric cancer cells proliferation. Despite the great progress in anti-cancer treatment achieved during the last decades, drug resistance and treatment refractoriness still extensively persists. Recently, accumulating studies have highlighted the role of miRNAs in drug resistance of gastric cancers by modulating some drug resistance-related proteins and genes expression. Pre-clinical reports indicate that miRNAs might serve as ideal biomarkers and potential targets, thus holding great promise for developing targeted therapy and personalized treatment for the patients with gastric cancer. Areas covered: This review provide a comprehensive overview of the current advances of miRNAs and molecular mechanisms underlying miRNA-mediated drug resistance in gastric cancer. We particularly focus on the potential values of drug resistance-related miRNAs as biomarkers and novel targets in gastric cancer therapy and envisage the future research developments of these miRNAs and challenges in translating the new findings into clinical applications. Expert opinion: Although the concrete mechanisms of miRNAs in drug resistance of gastric cancer have not been fully clarified, miRNA may be a promising theranostic approach. Further studies are still needed to facilitate the clinical applications of miRNAs in drug resistant gastric cancer.

Changes in the cellular microRNA profile by the intracellular expression of HIV-1 Tat regulator: A potential mechanism for resistance to apoptosis and impaired proliferation in HIV-1 infected CD4+ T cells

HIV-1 induces changes in the miRNA expression profile of infected CD4+ T cells that could improve viral replication. HIV-1 regulator Tat modifies the cellular gene expression and has been appointed as an RNA silencing suppressor. Tat is a 101-residue protein codified by two exons that regulates the elongation of viral transcripts. The first exon of Tat (amino acids 1–72) forms the transcriptionally active protein Tat72, but the presence of the second exon (amino acids 73–101) results in a more competent regulatory protein (Tat101) with additional functions. Intracellular, full-length Tat101 induces functional and morphological changes in CD4+ T cells that contribute to HIV-1 pathogenesis such as delay in T-cell proliferation and protection against FasL-mediated apoptosis. But the precise mechanism by which Tat produces these changes remains unknown. We analyzed how the stable expression of intracellular Tat101 and Tat72 modified the miRNA expression profile in Jurkat cells and if this correlated with changes in apoptotic pathways and cell cycle observed in Tat-expressing cells. Specifically, the enhanced expression of hsa-miR-21 and hsa-miR-222 in Jurkat-Tat101 cells was associated with the reduced expression of target mRNAs encoding proteins related to apoptosis and cell cycle such as PTEN, PDCD4 and CDKN1B. We developed Jurkat cells with stable expression of hsa-miR-21 or hsa-miR-222 and observed a similar pattern to Jurkat-Tat101 in resistance to FasL-mediated apoptosis, cell cycle arrest in G₂/M and altered cell morphology. Consequently, upregulation of hsa-miR-21 and hsa-miR-222 by Tat may contribute to protect against apoptosis and to anergy observed in HIV-infected CD4+ T cells.

Research progress on the relationship between zinc deficiency, related microRNAs, and esophageal carcinoma

Esophageal cancer (EC) is a common malignant tumor of the gastrointestinal tract with a high incidence in China. Zinc (Zn) deficiency is a key risk factor for the occurrence and development of EC and affects progression by regulating microRNA (miRNA, miR) expression. In addition, the dysregulation of miRNAs is accompanied by the dysregulation of their target genes in EC. In this paper, we review the potential molecular mechanisms between Zn deficiency and EC with the aim of providing new strategies and methods for early diagnosis, targeted therapy, and prognostic evaluation.

Inhibition of PTEN activity aggravates cisplatin-induced acute kidney injury

Cisplatin (cis-Diamminedichloroplatinum II) has been widely and effectively used in chemotherapy against tumors. Nephrotoxicity due to cisplatin is one of the most common clinical causes of acute kidney injury (AKI), which has a poor prognosis and high mortality. The signaling mechanisms underlying cisplatin-induced AKI are not completely understood. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor that negatively regulates the cell-survival pathway and is considered a double-edged sword in organ damage. In this study, we examined the effect that inhibiting PTEN activity in experimental models of cisplatin-induced AKI had on the degrees of AKI. Compared with vehicle mice, mice treated with bpV(pic) (specific inhibitor of PTEN) had exacerbated renal damage due to cisplatin-induced AKI. Furthermore, inhibition of PTEN activity increased cell apoptosis in the kidneys of mice induced by cisplatin. More inflammatory cytokines were activated after cisplatin treatment in mice of the bpV(pic)-treated group compared with vehicle mice, and these inflammatory cytokines may be partially derived from bone marrow cells. In addition, inhibiting PTEN activity decreased the phosphorylation of p53 in the pathogenesis of cisplatin-induced AKI. In summary, our study has demonstrated that inhibiting PTEN activity aggravates cisplatin-induced AKI via apoptosis, inflammatory reaction, and p53 signaling pathway. These results indicated that PTEN may serve as a novel therapeutic target for cisplatin-induced AKI.

Inhibition of miR-23a increases the sensitivity of lung cancer stem cells to erlotinib through PTEN/PI3K/Akt pathway

Epidermal growth factor receptor-targeted tyrosine kinase inhibitors (EGFR-TKIs) have become first-line drugs used for non-small cell lung cancer (NSCLC) treatment. However, drug resistance to EGFR-TKIs will be developed inevitably due to the repeated use of these drugs. In the present study, we isolated cancer stem cells (CSCs) from the PC9 NSCLC cell line. We then observed that the PC9 CSCs showed significant resistance to erlotinib compared with the PC9 non-CSCs. Erlotinib failed to suppress the phosphorylation of PI3K and AKT in PC9 CSCs, although the EGFR was inhibited sufficiently. Mechanically, we observed aberrant upregulation of microRNA-23a (miR-23a) and downregulation of PTEN in PC9 CSCs compared to PC9 non-CSCs. Luciferase reporter assays proved that PTEN was the target of miR-23a in PC9 CSCs. Furthermore, knockdown of miR-23a enhanced the antitumor effect of erlotinib by increasing the expression of PTEN. In addition, transfection with miR-23a inhibitors promoted the erlotinib-dependent inhibition of PI3K/AKT pathway, thus, suppressing the proliferation and inducing apoptosis in PC9 CSCs. These results propose that upregulation of miR-23a is a potential mechanism associated with resistance to EGFR-TKIs in lung cancer stem cells. Inhibition of miR-23a serves as a novel therapeutic strategy to eliminate the EGFR-TKIs resistance of lung cancer stem cells.

The prognostic value and potential drug target of phosphatase and tensin homolog in breast cancer patients: A meta-analysis

BACKGROUND

The prognostic significance of phosphatase and tensin homolog (PTEN) in patients with breast cancer (BC) remains controversial. The aims of our meta-analysis are to evaluate its association with clinicopathological characteristics and prognostic value in patients with breast cancer.

METHODS

PubMed, EMBASE, Web of Science, and China National Knowledge Infrastructure (CNKI) were systematically searched up to December 2016. The meta-analysis was performed using hazard ratio (HR), odds ratio (OR), and 95% confidence intervals (CI) as effect measures. A fixed or random effect model was used depending on the heterogeneity analysis. Statistical analysis was performed using Review manager software version 5.3.

RESULTS

Seventeen studies including 4343 patients with breast cancer were analyzed. The meta-analysis indicated that breast cancers with PTEN loss were significantly associated with the tumor size ≥2 cm group (ORFEM = 1.68, 95%CIFEM [1.34, 2.10]), negative expression of estrogen receptor (ORREM = 1.95, 95%CIREM [1.09, 3.49]), negative expression of progesterone receptor (ORFEM = 1.72, 95%CIFEM [1.43, 2.08]), the advanced stage (ORREM = 1.94, 95%CIREM [1.35, 2.80]), positive axillary lymph node metastasis (ORREM = 1.80, 95%CIREM [1.30, 2.50]), and the local recurrence (ORFEM = 1.70, 95%CIFEM [1.26, 2.28]). None of other clinicopathological parameters such as the HER2 status and distant metastasis were associated with PTEN loss. The decreased PTEN expression was significantly correlated with the overall survival (OS) of patients (HRREM = 1.83, 95%CIREM [1.32, 2.53]) and the disease-free survival (DFS) of patients (HRREM = 2.43, 95%CIREM [1.31, 4.53]).

CONCLUSION

Our meta-analysis demonstrates that PTEN loss is of particular importance for predicting breast cancer aggressiveness and poor prognosis. PTEN is a potential drug target for the development of individualized treatment in BC patients.

Exosomes containing miR-21 transfer the characteristic of cisplatin resistance by targeting PTEN and PDCD4 in oral squamous cell carcinoma

Resistance to chemotherapy remains a major obstacle for the effective treatment of oral squamous cell carcinoma (OSCC). Evidence for the involvement of exosomes as important regulators of cisplatin chemoresistance in OSCC is still poorly understood. Our objective of this study was to explore the roles for exosomes in modulating key cellular pathways mediating response to chemotherapy. We first developed the cisplatin-resistant cell lines (HSC-3-R and SCC-9-R) and found that the conditioned media from cisplatin-resistant OSCC cells enhanced the chemoresistance of parental OSCC cell. The release of exosomes was blocked by inhibitor (GW4869) and exosomes were found to be involved in the chemoresistance of parental OSCC cell transferred from resistant cells. The exosomes derived from resistant cells and parental cells were isolated. Then, the isolated exosomes were characterized and quantified by electron microscopy, qNano analysis, and western blot analysis. Exosomes derived from cisplatin-resistant OSCC cells were found to enhance the chemoresistance of OSCC cell and decrease the DNA damage signaling in response to cisplatin. It was also found that exosomes derived from cisplatin-resistant OSCC cells transferred miR-21 to OSCC parental cells and induced cisplatin resistance by targeting phosphatase and tensin homolog and programmed cell death 4. Furthermore, the roles of cisplatin-resistant OSCC cells-derived exosomes in vivo were confirmed by subcutaneous xenograft mouse model. Collectively, the results suggest that exosomes released from cisplatin-resistant OSCC cells transmit miR-21 to induce cisplatin resistance of OSCC cells.

MicroRNA-21 promotes bone mesenchymal stem cells migration in vitro by activating PI3K/Akt/MMPs pathway

MicroRNA-21 (miR-21) contributes to anti-apoptosis in bone marrow mesenchymal stem cells (BMSC), but its role in the migration of BMSCs remains vague. The aim of this study was to determine the possible effect of miR-21 on regulating BMSCs directional migration and the expression of MMP-2/MMP-9 in BMSCs in vitro. BMSCs were successfully infected with miR-21-up lentivirus. Cell migration using Transwell assay indicated that upregulated expression of miR-21 could significantly promote BMSCs migration. Western blot analysis indicated that miR-21 significantly upregulated the expression of MMP-2 and MMP-9, which were related to metastasis-associated genes. GM6001, the specific MMPs inhibitor, abrogated the upregulated expression of MMP-2/MMP-9 and abolished the positive effect of miR-21 on promoting BMSCs migration. Meanwhile, miR-21 significantly enhanced Akt phosphorylation, as measured by Western blot analysis. LY294002, an inhibitor of Akt activation, abrogated the phosphorylation of Akt and abolished the positive effect of miR-21 on promoting BMSCs migration and upregulating MMP-2/MMP-9 expression. These results suggest that miR-21 contributes to BMSCs migration by upregulating MMP-2/MMP-9, potentially via the PI3K/Akt pathway.

Correlation between microRNA expression, clinicopathological characteristics, and prognosis in patients with Non-small cell Lung Cancer: A retrospective study

Background

Lung cancer prognosis is related to various factors; however, the comprehensive relationship between these factors, including microRNAs (miRNAs), and lung cancer prognosis has not been determined. Thus, the aim of this study was to identify the key factors associated with lung cancer prognosis.

Methods

We retrospectively analyzed prognosis and relevant factors in 216 non‐small cell lung cancer (NSCLC) patients diagnosed from January 2008 to December 2014. Paraffin‐embedded lung tissue samples were used to detect miRNA‐21 and miRNA‐155. Clinical information was collected, including tumor malignancy, tumor node metastasis (TNM) classification, pathological type, site of the original tumor, and lung involvement. The association between factors and overall survival was analyzed. A Cox proportional hazard model was used to perform univariate and multivariate analyses.

Results

Age at surgery (hazard ratio [HR] 1.021, 95% confidence interval [CI] 1.003–1.040), TNM stages II (HR 3.858, 95% CI 2.449–6.078) and III (HR 3.099, 95% CI 1.911–5.023), and miRNA‐21 (HR 1.002, 95% CI 1.001–1.003) and miRNA‐155 expression (HR 1.131, 95% CI 1.064–1.202) were independent prognostic factors in NSCLC patients. MiRNA‐21 expression with TNM stages II (HR 1.282, 95% CI 1.197–1.372) and III (HR 1.247, 95% CI 1.149–1.354) interacted to affect prognosis in NSCLC patients.

Conclusions

Older age, higher clinical TNM stage, and increased miRNA‐21 and miRNA‐155 expression in NSCLC tissue were independently associated with poor survival in NSCLC patients. MiRNA‐21 expression and clinical TNM stage interacted to affect prognosis.

Metformin-induced ablation of microRNA 21-5p releases Sestrin-1 and CAB39L antitumoral activities

Metformin is a commonly prescribed type II diabetes medication that exhibits promising anticancer effects. Recently, these effects were found to be associated, at least in part, with a modulation of microRNA expression. However, the mechanisms by which single modulated microRNAs mediate the anticancer effects of metformin are not entirely clear and knowledge of such a process could be vital to maximize the potential therapeutic benefits of this safe and well-tolerated therapy. Our analysis here revealed that the expression of miR-21-5p was downregulated in multiple breast cancer cell lines treated with pharmacologically relevant doses of metformin. Interestingly, the inhibition of miR-21-5p following metformin treatment was also observed in mouse breast cancer xenografts and in sera from 96 breast cancer patients. This modulation occurred at the levels of both pri-miR-21 and pre-miR-21, suggesting transcriptional modulation. Antagomir-mediated ablation of miR-21-5p phenocopied the effects of metformin on both the clonogenicity and migration of the treated cells, while ectopic expression of miR-21-5p had the opposite effect. Mechanistically, this reduction in miR-21-5p enhanced the expression of critical upstream activators of the AMP-activated protein kinase, calcium-binding protein 39-like and Sestrin-1, leading to AMP-activated protein kinase activation and inhibition of mammalian target of rapamycin signaling. Importantly, these effects of metformin were synergistic with those of everolimus, a clinically relevant mammalian target of rapamycin inhibitor, and were independent of the phosphatase and tensin homolog status. This highlights the potential relevance of metformin in combinatorial settings for the treatment of breast cancer.

LF-MF inhibits iron metabolism and suppresses lung cancer through activation of P53-miR-34a-E2F1/E2F3 pathway

Our previous studies showed that low frequency magnetic fields (LF-MF) suppressed tumor growth and influenced the function of immune system. Nevertheless the mechanisms behind the effect of LF-MF still remain to be elucidated. In this study, Tumor- bearing mice subcutaneously inoculated with Lewis lung cancer cells were exposed to a LF-MF (0.4T, 7.5 Hz) for 35 days and Survival rate, tumor growth and the tumor markers were measured. Results showed that tumor growth was obviously inhibited with a prolonged survival of tumor- bearing mice by LF-MF exposure. In vitro experiments, LF-MF was found to induce cell growth arrest, cell senescence and inhibit iron metabolism of lung cancer cells. Moreover, LF-MF stabilized p53 protein via inhibiting cell iron metabolism and the stabilized p53 protein enhanced miR-34a transcription. Furthermore, increased expression of miR-34a induced cell proliferation inhibition, cell cycle arrest and cell senescence of lung cancer cells by targeting E2F1/E2F3. We also detected the relevant indicator in tumor tissue such as the iron content, the level of miR-34a and related protein, corresponding results were obtained. Taken together, these observations imply that LF-MF suppressed lung cancer via inhibiting cell iron metabolism, stabilizing p53 protein and activation P53- miR-34a-E2F1/E2F3 pathway.

MiR-21 is required for anti-tumor immune response in mice: an implication for its bi-directional roles

Here we show that miR-21, a microRNA known for its oncogenic activity, is also essential for mediating immune responses against tumor. Knockout of miR-21 in mice slowed the proliferation of both CD4⁺ and CD8⁺ cells, reduced their cytokine production and accelerated the grafted tumor growth. Further investigations indicated that miR-21 could activate CD4⁺ and CD8⁺ T cells via the PTEN/Akt pathway in response to stimulations. Taken together, these data suggest the key functions of miR-21 in mediating anti-tumor immune response and thereby uncover a bi-directional role of this traditionally known 'oncomiR' in tumorigenesis. Our study may provide new insights for the design of cancer therapies targeting microRNAs, with an emphasis on the dynamic and possibly unexpected role of these molecules.