PIK3R1 targeting by miR-21 suppresses tumor cell migration and invasion by reducing PI3K/AKT signaling and reversing EMT, and predicts clinical outcome of breast cancer

Identification of LIFR, PIK3R1, and MMP12 as Novel Prognostic Signatures in Gallbladder Cancer Using Network-Based Module Analysis

Background: Gallbladder cancer (GBC) is a rare and aggressive malignancy of the biliary tract with a dismal survival rate. Effective biomarkers and therapeutic targets are urgently needed.

Methods: We analyzed gene expression profiles of GBC to identify differentially expressed genes (DEGs) and then used these DEGs to identify functional module biomarkers based on protein functional interaction (FI) networks. We further evaluated the module-gene protein expression and clinical significance with immunohistochemistry staining (IHC) in a tissue microarray (TMA) from 80 GBC samples.

Results: Five functional modules were identified. Module 0 included classical cancer signaling pathways, such as Ras and PI3K-Akt; and modules 1–4 included genes associated with muscle cells, fibrinogen, extracellular matrix, and integrins, respectively. We validated the expression of LIFR, PIK3R1, and MMP12, which were hubs or functional nodes in modules. Compared with paired peritumoural tissues, we found that the expression of LIFR (P = 0.002) and PIK3R1 (P = 0.046) proteins were significantly downregulated, and MMP12 (P = 0.006) was significantly upregulated. Further prognostic analysis showed that patients with low expression of LIFR had shorter overall survival than those with high expression (log-rank test P = 0.028), the same trend as for PIK3R1 (P = 0.053) and MMP12 (P = 0.006). Multivariate analysis indicated that expression of MMP12 protein (hazard ratio [HR] = 0.429; 95% confidence interval [CI] 0.198, 0.930; P = 0.032) was one of the significant independent prognostic factors for overall survival.

Conclusions: We found a highly reliable FI network, which revealed LIFR, PIK3R1, and MMP12 as novel prognostic biomarker candidates for GBC. These findings could accelerate biomarker discovery and therapeutic development in this cancer.

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.

Deregulated Gab2 phosphorylation mediates aberrant AKT and STAT3 signaling upon PIK3R1 loss in ovarian cancer

Copy number loss of PIK3R1 (p85α) most commonly occurs in ovarian cancer among all cancer types. Here we report that ovarian cancer cells manifest a spectrum of tumorigenic phenotypes upon knockdown of PIK3R1. PIK3R1 loss activates AKT and p110-independent JAK2/STAT3 signaling through inducing changes in the phosphorylation of the docking protein Gab2, thereby relieving the negative inhibition on AKT and promoting the assembly of JAK2/STAT3 signalosome, respectively. Additional mechanisms leading to AKT activation include enhanced p110α kinase activity and a decrease in PTEN level. PIK3R1 loss renders ovarian cancer cells vulnerable to inhibition of AKT or JAK2/STAT3. The combination of AKT and STAT3 inhibitors significantly increases the anti-tumor effect compared to single-agent treatments. Together, our findings provide a rationale for mechanism-based therapeutic approach that targets tumors with loss of PIK3R1.

MicroRNA‑21 regulates the biological behavior of esophageal squamous cell carcinoma by targeting RASA1

MicroRNA‑21 (miR‑21) has been revealed to play a crucial role in regulating the biological behavior, including proliferation, migration, invasion and metastasis in certain cancers. However, its role in esophageal squamous cell carcinoma (ESCC) has yet to be elucidated. Based on the data of GSE13937 downloaded from Gene Expression Omnibus (GEO) database, miR‑21 was revealed to be one of the top 20 differentially expressed (DE) miRNAs screened using the Morpheus online tool. RAS p21 protein activator 1 (RASA1) was predicted as the target gene of miR‑21 using the predicting software and was combined with miR‑21 using the luciferase reporter assay. Its relative expression was significantly decreased, however, miR‑21 was increased in the tumor tissues compared to the normal adjacent tissues in patients with ESCC as determined by quantitative polymerase chain reaction (q‑PCR). Furthermore, overexpression of miR‑21 (mimic) could significantly decrease the gene level of RASA1. Conversely, downregulation of miR‑21 (inhibitor) significantly increased the gene level of RASA1, while downregulation of RASA1 (siRASA1) markedly increased the gene expression of miR‑21. Notably, the expression of Snail and vimentin were significantly increased by upregulation of miR‑21 and downregulation of RASA1. Transwell results revealed that miR‑21 and RASA1 regulated proliferation, migration and invasion in ESCC cells. In an in vivo model, miR‑21 inhibitor (antagomir) could inhibit tumor growth. In conclusion, miR‑21 regulated cell proliferation, migration, invasion and tumor growth of ESCC by directly targeting RASA1, which may have been achieved via regulation of Snail and vimentin. Anti‑miR‑21 revealed an antitumor effect. Thus, it may be considered as a possible target for ESCC therapy.

Overexpression of PIK3R1 promotes hepatocellular carcinoma progression

Background

Phosphoinositide-3-kinase, regulatory subunit 1 (PIK3R1) could regulate cancer cell proliferation important for cancer cell proliferation; however, its role in Hepatocellular carcinoma (HCC) remains largely unknown. Here, we investigated the role of PIK3R1 in HCC and examined the underlying molecular mechanisms.

Methods

The expression of PIK3R1 was evaluated by immunohistochemistry and qRT-PCR in a series of HCC tissues. The mRNA and protein expression of PIK3R1 was used by qRT-PCR and western blot assays in a series of human HCC cell lines, and then we choose MHCC97H and HCCLM3 cells as a model to investigate the effect of PIK3R1 on HCC progression. The effects of PIK3R1 knowdown on cell proliferation, migration, apoptosis of HCC were assessed by the MTT assay, clonogenic assays, wound healing assay and flow cytometry in vitro. Western blot assay was performed to assess the expression changes of PI3K/AKT/mTOR signaling pathway.

Results

Our results found that PIK3R1 was highly expressed in HCC tissues compared with adjacent normal tissues. Knockdown of PIK3R1 inhibited the proliferation, migration and promoted apoptosis of HCC cell lines. In addition, we proved that knockdown of PIK3R1 downregulated p-PI3K, p-AKT, and p-mTOR expressions in MHCC97H and HCCLM3 cells.

Conclusions

In conclusion, PIK3R1 providing potential novel targets for the treatment of HCC.

High-throughput chemical screening to discover new modulators of microRNA expression in living cells by using graphene-based biosensor

MicroRNAs (miRNAs) are important regulatory RNAs that control gene expression in various biological processes. Therefore, control over the disease-related miRNA expression is important both for basic research and for a new class of therapeutic modality to treat serious diseases such as cancer. Here, we present a high-throughput screening strategy to identify small molecules that modulate miRNA expression in living cells. The screen enables simultaneous monitoring of the phenotypic cellular changes associated with the miRNA expression by measuring quantitative fluorescent signals corresponding to target miRNA level in living cells based on a novel biosensor composed of peptide nucleic acid and nano-sized graphene oxide. In this study, the biosensor based cellular screening of 967 compounds (including FDA-approved drugs, enzyme inhibitors, agonists, and antagonists) in cells identified four different classes of small molecules consisting of (i) 70 compounds that suppress both miRNA-21 (miR-21) expression and cell proliferation, (ii) 65 compounds that enhance miR-21 expression and reduce cell proliferation, (iii) 2 compounds that suppress miR-21 expression and increase cell proliferation, and (iv) 21 compounds that enhance both miR-21 expression and cell proliferation. We further investigated the hit compounds to correlate cell morphology changes and cell migration ability with decreased expression of miR-21.

MicroRNA-21: A promising biomarker for the prognosis and diagnosis of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer worldwide. The high mortality rate of NSCLC is due to a limited number of diagnosis being made at an early stage of disease. Therefore, the development of a novel biological marker for the diagnosis and prognosis prediction of NSCLC remains urgent. Current literature shows that microRNA-21 (miRNA-21/miR-21), as an oncogenic miRNA, is involved in the growth, metastasis and apoptosis of NSCLC cells through its control of various target molecules and signaling pathways. Notably, a growing body of evidence further shows that miR-21 is closely associated with the prognosis prediction, recurrence and diagnosis of cancer patients, indicating that miR-21 may be a novel promising biomarker for the diagnosis and prognosis prediction of NSCLC. The present review aimed to provide a summary of recent findings on the associated progression toward finding a novel biomarker for NSCLC.

Oridonin inhibits VEGF-A-associated angiogenesis and epithelial-mesenchymal transition of breast cancer in vitro and in vivo

Metastasis is the primary cause of mortality in patients with breast cancer and lacks effective therapeutic agents. Oridonin, an active diterpenoid compound isolated from Rabdosia rubescens, was identified to be the most potent anti-tumor ingredient. However, the molecular mechanisms responsible for its anti-metastatic effects remain unclear. In the present study, oridonin significantly suppressed the migration, invasion and adhesion of MDA-MB-231 and 4T1 breast cancer cells, and inhibited tube formation of human umbilical vein endothelial cells in a dose-dependent manner. The expression levels of epithelial-mesenchymal transition (EMT)-associated marker and the hypoxia inducible factor 1α (HIF-1α)/vascular endothelium growth factor (VEGF) signaling pathway mRNA and proteins were determined by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively in vitro. The results demonstrated that oridonin effectively inhibited EMT as demonstrated by the significant increases in the expression levels of E-cadherin, and decreased expression of N-cadherin, Vimentin and Snail. In addition, oridonin exerted its anti-angiogenesis activity through significantly decreasing HIF-1α, VEGF-A and VEGF receptor-2 protein expression. Furthermore, oridonin was demonstrated to decrease the micro-vessel density as evidenced by the decreased expression of cluster of differentiation 31, a marker for neovasculature. In brief, oridonin inhibits tumor cell migration, invasion and adhesion, as well as tumor angiogenesis, which are mediated by suppressing EMT and the HIF-1α/VEGF signaling pathway. The results of the present study suggest that oridonin may be a promising anti-metastatic agent in breast cancer treatment.

Exosome-mediated gefitinib resistance in lung cancer HCC827 cells via delivery of miR-21

Acquired resistance to gefitinib remains a major challenge in cancer treatment. In the present study, the effect of exosomes on the transmission of gefitinib resistance from gefitinib-resistant HCC827 lung cancer cells (H827R) to their gefitinib-sensitive counterparts and the potential underlying mechanisms by which this occurs was investigated. Exosomes were obtained from the cell supernatant using ultracentrifugation and the ExoQuick-TC exosome precipitation solution. Drug resistance was assessed by flow cytometry, apoptosis assays and cell counting kit-8 assays. The expression of microRNA (miR)-21 was analyzed by reverse transcription-quantitative polymerase chain reaction. Exosomes released by H827R cells (R/exo) may decrease the sensitivity of the human NSCLC HCC827 cell line to gefitinib. The results indicated that miR-21 expression was increased in R/exo and R/exo-treated H827S cells. However, miR-21 inhibition abrogated exosome-mediated drug resistance. Phosphorylated-protein kinase B (p-Akt), which is downstream of miR-21, was downregulated following gefitinib treatment; however, R/exo pretreatment elevated p-Akt levels and promoted the activation of Akt. By contrast, miR-21 inhibition reduced p-Akt expression. Therefore, the induction of miR-21 via exosomes and the activation of Akt may be mechanisms by which exosomes mediate the transfer of drug resistance.

Silencing of ASPP2 promotes the proliferation, migration and invasion of triple-negative breast cancer cells via the PI3K/AKT pathway

Apoptosis-stimulating p53 protein 2 (ASPP2) is an apoptosis inducer that acts via binding with p53 and then enhancing the transcriptional activities toward pro‑apoptosis genes. ASPP2 has recently been reported to serve a major role in p53‑independent pathways. Triple‑negative breast cancer (TNBC) is a type of breast cancer that is more aggressive and highly lethal when p53 is mutated. In the present study, the mRNA level of ASPP2 was found to be suppressed in breast tumors compared with that in adjacent normal breast tissues, and the expression of ASPP2 was also decreased in a series of breast cancer cell lines compared with that in MCF‑10A normal breast cells. Downregulation of ASPP2 by specific small interfering RNA (siRNA) transfection was able to promote cell growth, reduce cell apoptosis, and contribute to cell migration and invasion. Furthermore, downregulation of ASPP2 promoted cell epithelial‑mesenchymal transition (EMT) in MDA‑MB‑231 and HCC‑1937 TNBC cells. Furthermore, it was found that when ASPP2 siRNA was transfected into MDA‑MB‑231 and HCC‑1937 cells, the expression of phosphoinositide‑3‑kinase regulatory subunit 1 (p85α) decreased and phosphorylation of protein kinase B (AKT) increased, which are key molecular regulators in the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. In conclusion, the present data indicated that ASPP2 had a crucial influence on the proliferation and metastasis in TNBC, and that the functional mechanism may be p53‑independent to a great extent. ASPP2 and its link with the PI3K/AKT pathway deserve further investigation and may provide novel insights into therapeutic targets for TNBC.

miRNAs as potential regulators of mTOR pathway in renal cell carcinoma

Renal cell carcinoma (RCC) is the most commonly occurring solid cancer of the adult kidney with the majority of RCC cases being detected accidentally. The most aggressive subtype is clear cell RCC (ccRCC). miRNAs, a family of small noncoding RNAs regulating gene expression have been identified as key biological modulators. The von Hippel-Lindau pathway is one of the signaling pathways involved in the pathophysiology of ccRCC. Another oncogenic mechanism involves the activation of PI3K/AKT/mTOR signaling and serves as a central regulator of cell metabolism, proliferation and survival. Several studies have described the involvement of miRNA dysregulation in the pathogenesis and progression of ccRCC. These molecules can be considered as potential diagnostic and prognostic biomarkers, allowing response to therapy to be monitored.

Tissue and serum microRNA profile of oral squamous cell carcinoma patients

Head and neck cancer is characterized by malignant tumors arising from the epithelium covering the upper aerodigestive tract, and the majority of these epithelial malignancies are squamous cell carcinomas (SCCs) of the oral cavity (OSCCs). The aim of the current work was to identify miRNAs regulated in OSCC cancerous tissue when compared to a healthy adjacent tissue and to verify the presence of the same miRNAs in the circulation of these patients. For that serum samples and biopsies of healthy and tumor tissues were collected from five patients diagnosed with OSCC of the oral cavity, RNA was extracted from these samples and microRNAs libraries were prepared and sequenced. A total 255 miRNAs were identified in tissue and 381 different miRNAs were identified in serum samples. When comparing the miRNA expression between tumor and healthy tissue we identified 48 miRNAs (25 down- and 23 up-regulated) that were differentially expressed (FDR < 0.05). From these 48 differentially expressed miRNAs in tissue, 30 miRNAs were also found in the serum of the same patients. hsa-miR-32-5p was up-regulated in tumor compared to healthy tissue in our study, and was previously shown to be up-regulated in the serum of OSCC patients. Therefore, this suggests that miRNAs can be used as potential non-invasive biomarkers of OSCC.

Interrelation of the Circulating and Tissue MicroRNA-21 with Tissue PDCD4 Expression and the Invasiveness of Iraqi Female Breast Tumors

The changes in the translational repression and variation in mRNA degradation induced by micro RNA are important aspects of tumorigenesis. The association of microRNA-21 with clinicopathologic features and expression of programed cell death 4 (PDCD4) in Iraqi female's with breast tumors has not been studied. MicroRNAs were extracted from a set of 60 breast tumor tissues and blood samples of females with breast cancer and benign breast lesions obtained after breast-reductive surgery, and only blood samples from 30 normal volunteers. These extracts were evaluated for miR-21 expression by quantitative RT-PCR. Analysis of PDCD4 protein expression was carried out as miR-21 target gene by immunohistochemical tests and correlating the results with patients' clinicopathological features. Significant overexpression of miRNA-21 was found in breast cancer group. The fold increase in the miR-21 gene expression was significantly higher in circulating exosomes and breast tissues of breast cancer patients as compared to other groups (P < 0.001). Overexpression of miR-21 was also significantly associated with the advanced tumor stage and histological grade. In breast cancer patients, PDCD4 protein expression was decreased to about 70% of the level in the control group. The delta Ct of exosomal and breast tissue miRNA-21 was negatively associated with PDCD4 expression. In conclusion, the translational repression of the PDCD4 induced by the high expression of miR-21 promotes breast cell transformation and development of breast tumor, and circulating miR-21 level could be applied to the screening panels for early detection of women breast cancer.

Propofol regulates the expression of TLR4 through miR‑21 in human umbilical vein endothelial cells

Propofol (2,6-diisopropylphenol) is one of the most commonly used intravenous anesthetics. Anesthetics can regulate the inflammatory process; however, the mechanism remains to be fully elucidated. The present study aimed to investigate whether and how propofol affects the inflammatory reaction in human umbilical vein endothelial cells (HUVECs). The expression levels of Toll‑like receptor 4 (TLR4) and cluster of differentiation 14 (CD14) were determined in HUVECs treated with propofol and lipopolysaccharide (LPS) using western blot and reverse transcription‑quantitative polymerase chain reaction analyses. In addition, whether propofol regulated the expression of TLR4 though microRNA (miR)‑21 was examined. The results showed that LPS promoted the expression levels of TLR4, CD14 and tumor necrosis factor α (TNFα), and suppressed the expression of miR‑21 in HUVECs. Propofol suppressed the expression levels of TLR4, CD14 and TNFα, and upregulated the expression of miR‑21 in a concentration‑dependent manner. miR‑21 downregulated the expression of TLR4 at the mRNA and protein levels, whereas the miR‑21 mimic reversed the effect of LPS on the expression of TLR4. In addition, the miR‑21 inhibitor inhibited the downregulatory effect of propofol on the expression of TLR4. TargetScan analysis showed that TLR4 was included in the list of targets of miR‑21. Fluorescent reporter assays showed that the miR‑21 mimic and propofol treatment reduced the fluorescence intensity in cells transfected with a reporter vector containing the wild‑type TLR4 3'‑untranslated region. Taken together, the results of the present study demonstrated that propofol regulated the expression of TLR4 in HUVECs through miR‑21.

EGFR pathway subgroups in Chilean colorectal cancer patients, detected by mutational and expression profiles, associated to different clinicopathological features

Colorectal cancer is a multistep process affecting several signaling pathways including EGFR (epidermal growth factor receptor), a therapeutic target for metastatic disease. Our aim was to characterize the mutational and expression profiles of the EGFR pathway in colorectal tumors and to integrate these results according to five previously defined groups. We screened seven genes for mutations ( KRAS-BRAF-PIK3CA-PIK3R1-AKT1-MAP2K1-PTEN) and six proteins (EGFR-p110α-p85α-PTEN-phosphoAKT-phosphoMEK1) by immunohistochemistry, PTEN deletion, and MSI. At least one mutated gene was observed in 68% of tumors ( KRAS 45%, PIK3CA 21%, BRAF 14%, and PTEN 7%). PTEN deletion was observed in 10.7% of tumors and 19.6% were MSI-High. In all, 54% of tumors showed a high EGFR expression, 48% p110α, 4.4% phosphoAKT, and 22% phosphoMEK1; and 43% showed low PTEN expression and 22% p85α. In total, five groups of tumors were defined based on MSI, BRAF, and KRAS mutations. Three groups gather mainly early-stage tumors, whereas a fourth group is mostly conformed by advanced tumors. We described here that 71.4% of tumors from one group have a mutated PI3K/PTEN pathway, in comparison to other groups having 32%, 27%, and 25%. In addition, the five groups are differentiated by molecular features such as EGFR, p85α, p110α, and PTEN, showing variable expression among tumor groups. In conclusion, alterations on the EGFR pathway were found in a high percentage of colorectal cancer patients. Using the integration of diverse molecular markers, we ratified previous classification in an ethnic group having relevant genetic differences and living in a different environmental background, adding complementary molecular targets related to therapy.

Targeting epithelial-mesenchymal plasticity in cancer: clinical and preclinical advances in therapy and monitoring

The concept of epithelial-mesenchymal plasticity (EMP), which describes the dynamic flux within the spectrum of phenotypic states that invasive carcinoma cells may reside, is being increasingly recognised for its role in cancer progression and therapy resistance. The myriad of events that are able to induce EMP, as well as the more recently characterised control loops, results in dynamic transitions of cancerous epithelial cells to more mesenchymal-like phenotypes through an epithelial-mesenchymal transition (EMT), as well as the reverse transition from mesenchymal phenotypes to an epithelial one. The significance of EMP, in its ability to drive local invasion, generate cancer stem cells and facilitate metastasis by the dissemination of circulating tumour cells (CTCs), highlights its importance as a targetable programme to combat cancer morbidity and mortality. The focus of this review is to consolidate the existing knowledge on the strategies currently in development to combat cancer progression via inhibition of specific facets of EMP. The prevalence of relapse due to therapy resistance and metastatic propensity that EMP endows should be considered when designing therapy regimes, and such therapies should synergise with existing chemotherapeutics to benefit efficacy. To further improve upon EMP-targeted therapies, it is imperative to devise monitoring strategies to assess the impact of such treatments on EMP-related phenomenon such as CTC burden, chemosensitivity/-resistance and micrometastasis in patients.

MiR-503 modulates epithelial-mesenchymal transition in silica-induced pulmonary fibrosis by targeting PI3K p85 and is sponged by lncRNA MALAT1

Silicosis is a kind of chronic, progressive and incurable lung fibrotic diseases with largely unknown and complex pathogenesis and molecular mechanisms. Mounting evidence suggests that microRNAs (miRNAs, miRs) are involved in the pathogenesis of silicosis. Our previous study based on miRNA microarray had shown that the expression levels of miR-503 were down-regulated in mouse lung tissues of silica-induced pulmonary fibrosis. Here, we validated the decreased expression of miR-503 in the fibrotic mouse lung tissues, human bronchial epithelial cells (HBE) and human lung adenocarcinoma A549 cells which were exposed to silica. In addition, overexpressed miR-503 inhibited silica-induced pulmonary fibrosis by attenuating the severity and the distribution of lesions in vivo and limiting the process of epithelial-mesenchymal transition (EMT) in vitro. Our molecular study further demonstrated that PI3K p85 is one of the target genes of miR-503 and the downstream molecules (Akt, mTOR and Snail) are tightly associated with EMT. Furthermore, the up-regulated lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), acted as a competing endogenous RNA (ceRNA), can directly bound to miR-503, which indicated that lncRNA MALAT1 may modulate the expression of miR-503 thus triggering the activation of downstream fibrotic signaling pathways. Taken together, our data suggested that MALAT1-miR-503-PI3K/Akt/mTOR/Snail pathway plays critical roles in silica-induced pulmonary fibrosis.

MicroRNA-21 regulates the proliferation and apoptosis of cervical cancer cells via tumor necrosis factor-α

The proliferation and apoptosis of tumor cells are regulated by a variety of microRNAs (miRs). miR-21 can inhibit the apoptosis of cancer cells in vitro. Tumor necrosis factor α (TNF-α) serves an important role in the induction of proliferation of cervical cancer cells. Previous studies have demonstrated that the expression level of miR-21 is associated with TNF-α expression in alveolar macrophages. However, to the best of our knowledge, whether miR-21 regulates TNF-α in cervical cells has not been reported. The present study was designed to investigate whether miR-21 regulates TNF-α expression, proliferation and apoptosis of cervical cancer cells. miR-21, miR-21 inhibitor and control miRNA were synthesized and transfected into HeLa cervical cancer cells. Reverse transcription-quantitative polymerase chain reaction was used to measure the expression levels of miR-21 and TNF-α at the mRNA level. Western blotting was used to measure the expression levels of TNF-α at the protein level. MTT assay and Hoechest-33342 staining were used to measure the proliferation and apoptosis of HeLa cells. miR-21 was identified to upregulate the mRNA and protein expression levels of TNF-α. Furthermore, upregulation of TNF-α enhanced the proliferation capability of HeLa cells. Changes in the expression levels of miR-21 and TNF-α did not significantly affect the apoptosis of Hela cells. In conclusion, the present study demonstrated that miR-21 regulates the expression of TNF-α in HeLa cells. Additionally, the expression level of TNF-α was positively associated with the proliferation capability of Hela cells, but not apoptosis. Therefore, miR-21 regulates the proliferation of HeLa cells through regulation of TNF-α. These results provide novel potential therapeutic targets for the treatment of cervical cancer.

Co-delivery of microRNA-21 antisense oligonucleotides and gemcitabine using nanomedicine for pancreatic cancer therapy

Tumor metastasis occurs naturally in pancreatic cancer, and the efficacy of chemotherapy is usually poor. Precision medicine, combining downregulation of target genes with chemotherapy drugs, is expected to improve therapeutic effects. Therefore, we developed a combined therapy of microRNA‐21 antisense oligonucleotides (ASO‐miR‐21) and gemcitabine (Gem) using a targeted co‐delivery nanoparticle (NP) carrier and investigated the synergistic inhibitory effects on pancreatic cancer cells metastasis and growth. Polyethylene glycol–polyethylenimine–magnetic iron oxide NPs were used to co‐deliver ASO‐miR‐21 and Gem. An anti‐CD44v6 single‐chain variable fragment (scFv_CD44v6) was used to coat the particles to obtain active and targeted delivery. Our results showed that the downregulation of the oncogenic miR‐21 by ASO resulted in upregulation of the tumor‐suppressor genes PDCD4 and PTEN and the suppression of epithelial–mesenchymal transition, which inhibited the proliferation and induced the clonal formation, migration, and invasion of pancreatic cancer cells in vitro. The co‐delivery of ASO‐miR‐21 and Gem induced more cell apoptosis and inhibited the growth of pancreatic cancer cells to a greater extent than single ASO‐miR‐21 or Gem treatment in vitro. In animal tests, more scFv_CD44v6‐PEG‐polyethylenimine/ASO‐magnetic iron oxide NP/Gem accumulated at the tumor site than non‐targeted NPs and induced a potent inhibition of tumor proliferation and metastasis. Magnetic resonance imaging was used to observed tumor homing of NPs. These results imply that the combination of miR‐21 gene silencing and Gem therapy using an scFv‐functionalized NP carrier exerted synergistic antitumor effects on pancreatic cancer cells, which is a promising strategy for pancreatic cancer therapy.

Phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog as therapeutic targets in breast cancer

Breast cancer is the most commonly diagnosed cancer among women in Turkey and worldwide. It is considered a heterogeneous disease and has different subtypes. Moreover, breast cancer has different molecular characteristics, behaviors, and responses to treatment. Advances in the understanding of the molecular mechanisms implicated in breast cancer progression have led to the identification of many potential therapeutic gene targets, such as Breast Cancer 1/2, phosphatidylinositol 3-kinase catalytic subunit alpha, and tumor protein 53. The aim of this review is to summarize the roles of phosphatidylinositol 3-kinase regulatory subunit 1 (alpha) (alias p85α) and phosphatase and tensin homolog in breast cancer progression and the molecular mechanisms involved. Phosphatase and tensin homolog is a tumor suppressor gene and protein. Phosphatase and tensin homolog antagonizes the phosphatidylinositol 3-kinase/AKT signaling pathway that plays a key role in cell growth, differentiation, and survival. Loss of phosphatase and tensin homolog expression, detected in about 20%-30% of cases, is known to be one of the most common tumor changes leading to phosphatidylinositol 3-kinase pathway activation in breast cancer. Instead, the regulatory subunit p85α is a significant component of the phosphatidylinositol 3-kinase pathway, and it has been proposed that a reduction in p85α protein would lead to decreased negative regulation of phosphatidylinositol 3-kinase and hyperactivation of the phosphatidylinositol 3-kinase pathway. Phosphatidylinositol 3-kinase regulatory subunit 1 protein has also been reported to be a positive regulator of phosphatase and tensin homolog via the stabilization of this protein. A functional genetic alteration of phosphatidylinositol 3-kinase regulatory subunit 1 that results in reduced p85α protein expression and increased insulin receptor substrate 1 binding would lead to enhanced phosphatidylinositol 3-kinase signaling and hence cancer development. Phosphatidylinositol 3-kinase regulatory subunit 1 underexpression was observed in 61.8% of breast cancer samples. Therefore, expression/alternations of phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog genes have crucial roles for breast cancer progression. This review will summarize the biological roles of phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog in breast cancer, with an emphasis on recent findings and the potential of phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog as a therapeutic target for breast cancer therapy.

MicroRNA-21 Regulates the Proliferation, Differentiation, and Apoptosis of Human Renal Cell Carcinoma Cells by the mTOR-STAT3 Signaling Pathway

MicroRNA-21 (miRNA-21), a kind of short, noncoding RNAs, functioned as a tumor marker and was upregulated in renal cell carcinoma (RCC). However, the underlying mechanisms of miRNA-21 in RCC were uncertain. Therefore, the effects and mechanisms of miRNA-21 on the proliferation, differentiation, and apoptosis of cultured human RCC cells were further investigated in this study. After slicing miRNA-21 in RCC cells, the viability, mRNA expression of C/EBPα and PPARγ, caspase 3 activity, and protein expression of mTOR, STAT3, and pSTAT3 were determined. It was found that knockdown of miRNA-21 downregulated the optical density (OD) value of cells, inhibited mRNA expression of PPARγ and C/EBPα, and enhanced activity of caspase 3. Furthermore, protein expression of pSTAT3 was also decreased in the absence of miRNA-21. Notably, miRNA-21-changed proliferation, differentiation, and apoptosis of human RCC cells were partially regulated following the block of the mTOR-STAT3 signaling pathway by the mTOR inhibitor (XL388). It was indicated that miRNA-21 promoted proliferation and differentiation and decreased apoptosis of human RCC cells through the activation of the mTOR-STAT3 signaling pathway.

Corepressor metastasis-associated protein 3 modulates epithelial-to-mesenchymal transition and metastasis

Worldwide, metastasis is the leading cause of more than 90% of cancer-related deaths. Currently, no specific therapies effectively impede metastasis. Metastatic processes are controlled by complex regulatory networks and transcriptional hierarchy. Corepressor metastasis-associated protein 3 (MTA3) has been confirmed as a novel component of nucleosome remodeling and histone deacetylation (NuRD). Increasing evidence supports the theory that, in the recruitment of transcription factors, coregulators function as master regulators rather than passive passengers. As a master regulator, MTA3 governs the target selection for NuRD and functions as a transcriptional repressor. MTA3 dysregulation is associated with tumor progression, invasion, and metastasis in various cancers. MTA3 is also a key regulator of E-cadherin expression and epithelial-to-mesenchymal transition. Elucidating the functions of MTA3 might help to find additional therapeutic approaches for targeting components of NuRD.

Emerging Role of MicroRNAs in mTOR Signaling

Mechanistic target of rapamycin (mTOR) is a conserved serine/threonine kinase that plays a critical role in the control of cellular growth and metabolism. Hyperactivation of mTOR pathway is common in human cancers, driving uncontrolled proliferation. MicroRNA (miRNA) is a class of short noncoding RNAs that regulate the expression of a wide variety of genes. Deregulation of miRNAs is a hallmark of cancer. Recent studies have revealed interplays between miRNAs and the mTOR pathway during cancer development. Such interactions appear to provide a fine-tuning of various cellular functions and contribute qualitatively to the behavior of cancer. Here we provide an overview of current knowledge regarding the reciprocal relationship between miRNAs and mTOR pathway: regulation of mTOR signaling by miRNAs and control of miRNA biogenesis by mTOR. Further research in this area may prove important for the diagnosis and therapy of human cancer.

miR-21 and KLF4 jointly augment epithelial‑mesenchymal transition via the Akt/ERK1/2 pathway

miR-21 induces epithelial-mesenchymal transition (EMT) of human cholangiocarcinoma (CCA) cells. However, the mechanism by which this occurs remains unclear. In the present study, high throughput platform was employed to detect the genes that are differential expressed in QBC939 cells transfected with a hsa-miR-21 antagomir or control vectors. The EMT-related Krüppel-like factor 4 (KLF4) gene was down-regulated after miR-21 was knocked down. Overexpression of miR-21 upregulated KLF4, Akt, ERK and mesenchymal cell markers (N-cadherin and vimentin), downregulated the expression of epithelial cell marker E-cadherin and reduced cell migration and invasion. Immunohistochemistry showed that KLF4, pAkt and pERK were upregulated in tumor xenografts transfected with miR-21 mimics. Inhibitors of the PI3K-Akt and ERK1/2 pathways, LY294002 and U0126, significantly suppressed the EMT phenotype. The present data demonstrated that overexpression of miR-21, accompanied with KLF4, augmented the EMT via inactivation of Akt and ERK1/2 pathways. In conclusion, we have identified a novel mechanism that may be targeted in an attempt to relieve the malignant biological behavior of CCA cells.

Argonaute 2 immunoprecipitation revealed large tumor suppressor kinase 1 as a novel proapoptotic target of miR-21 in T cells

MicroRNA (miR)-21 is an important suppressor of T-cell apoptosis that is also overexpressed in many types of cancers. The exact mechanisms underlying the antiapoptotic effects of miR-21 are not well understood. In this study, we used the Jurkat T-cell line as a model to identify apoptosis-associated miR-21 target genes. We showed that expression of miR-21 rapidly increases upon αCD3/αCD28 activation of Jurkat cells. Inhibition of miR-21 reduced cell growth which could be explained by an increase in apoptosis. MicroRNA target gene identification by AGO2 RNA-immunoprecipitation followed by gene expression microarray (RIP-Chip) resulted in the identification of 72 predicted miR-21 target genes that were at least twofold enriched in the AGO2-IP fraction of miR-21 overexpressing cells. Of these, 71 were at least twofold more enriched in the AGO2-IP fraction of miR-21 overexpressing cells as compared to AGO2-IP fraction of control cells. The target gene for which the AGO2-IP enrichment was most prominently increased upon miR-21 overexpression was the proapoptotic protein LATS1. Luciferase reporter assays and western blot analysis confirmed targeting of LATS1 by miR-21. qRT-PCR analysis in primary T cells showed an inverse expression pattern between LATS1 transcript levels and miR-21 upon T-cell stimulation. Finally, LATS1 knockdown partially rescued the miR-21 inhibition-induced impaired cell growth. Collectively, these data identify LATS1 as a miR-21 target important for the antiapoptotic function of miR-21 in T cells and likely also in many types of cancer.

Changes of Ovarian microRNA Profile in Long-Living Ames Dwarf Mice during Aging

The Ames dwarf (df/df) mice have extended longevity and can preserve the ovarian reserve longer than Normal (N) mice. Based on this, the aim of our study was to evaluate the ovarian microRNA (miRNA) profile in young and aged df/df and N mice. Ovarian tissue was collected at 5–6 months and at 21–22 months of age for miRNA sequencing. We detected a total of 404 miRNAs in the ovarian samples, from which the abundance of 22 and 33 miRNAs changed with age in N and df/df mice, respectively. Of these, only three miRNAs were commonly regulated with age between N and df/df mice, indicating a very divergent miRNA profile between genotypes. We also detected that 46 miRNAs were regulated between N and df/df mice, of which 23 were regulated exclusively in young mice, 12 exclusively in old mice and 12 commonly regulated at young and old ages. Many genes likely to be targeted by these miRNAs are involved in the FoxO, mTOR, PI3k/Akt and insulin signaling pathways. These results suggest that the aging process has a differential impact on the ovarian miRNA profile in df/df mice, and suggest that these miRNAs can be central players in the maintenance of a younger ovarian phenotype.

Integrated Analysis of Long Noncoding RNA and mRNA Expression Profile in Advanced Laryngeal Squamous Cell Carcinoma

Long non-coding RNA (lncRNA) plays an important role in tumorigenesis. However, the expression pattern and function of lncRNAs in laryngeal squamous cell carcinoma (LSCC) are still unclear. To investigate the aberrantly expressed lncRNAs and mRNAs in advanced LSCC, we screened lncRNA and mRNA expression profiles in 9 pairs of primary Stage IVA LSCC tissues and adjacent non-neoplastic tissues by lncRNA and mRNA integrated microarrays. Gene Ontology and pathway analysis were performed to find out the significant function and pathway of the differentially expressed mRNAs, gene-gene functional interaction network and ceRNA network were constructed to select core mRNAs, and lncRNA-mRNA expression correlation network was built to identify the interactions between lncRNA and mRNA. qRT-PCR was performed to further validate the expressions of selected lncRNAs and mRNAs in advanced LSCC. We found 1459 differentially expressed lncRNAs and 2381 differentially expressed mRNAs, including 846 up-regulated lncRNAs and 613 down-regulated lncRNAs, 1542 up-regulated mRNAs and 839 down-regulated mRNAs. The mRNAs ITGB1, HIF1A, and DDIT4 were selected as core mRNAs, which are mainly involved in biological processes, such as matrix organization, cell cycle, adhesion, and metabolic pathway. LncRNA-mRNA expression correlation network showed LncRNA NR_027340, MIR31HG were positively correlated with ITGB1, HIF1A respectively. LncRNA SOX2-OT was negatively correlated with DDIT4. qRT-PCR further validated the expression of these lncRNAs and mRNAs. The work provides convincing evidence that the identified lncRNAs and mRNAs are potential biomarkers in advanced LSCC for further future studies.

microRNA from brush biopsy to characterize oral squamous cell carcinoma epithelium

Few cancers are diagnosed based on RNA expression signatures. Oral squamous cell carcinoma (OSCC) is no exception; it is currently diagnosed by scalpel biopsy followed by histopathology. This study sought to identify oral tumor epithelial microRNA (miRNA) expression changes to determine if these changes could be used to diagnose the disease noninvasively. Analysis of miRNA profiles from surgically obtained OSCC tissue, collected under highly standardized conditions for The Cancer Genome Atlas, was done to determine the potential accuracy in differentiating tumor from normal mucosal tissue. Even when using small 20 subject datasets, classification based on miRNA was 90 to 100% accurate. To develop a noninvasive classifier for OSSC, analysis of brush biopsy miRNA was done and showed 87% accuracy in differentiating tumor from normal epithelium when using RT‐qPCR or miRNAseq to measure miRNAs. An extensive overlap was seen in differentially expressed miRNAs in oral squamous cell carcinoma epithelium obtained using brush biopsy and those reported in saliva and serum of oral squamous cell carcinoma patients in several studies. This suggested that nonselective release of these miRNAs into body fluids from tumor epithelium was largely responsible for the changes in levels in these fluids seen with this disease. Using a variation in mirRPath we identified the KEGG pathway of neurotrophin signaling as a target of these miRNAs disregulated in tumor epithelium. This highlights the utility of brush biopsy of oral mucosa to allow simple acquisition of cancer relevant miRNA information from tumor epithelium.

Prognostic value of circulating microRNA-21 for breast cancer: a systematic review and meta-analysis

BACKGROUND

There is an urgent need for novel noninvasive prognostic molecular tumor marker for monitoring the recurrence of breast cancer. MicroRNA-21 (miR-21) play a crucial role in the progression and aggressiveness of breast cancer, but its prognostic significance for patients with breast cancer remains inconclusive. The aim of this meta-analysis is to summarize the role of circulating miR-21 as a molecular marker in patients with breast cancer.

MATERIAL AND METHODS

Eligible studies were searched from the PubMed, EMBASE and Web of Science databases. The χ² and I² tests were used to evaluate heterogeneity between studies. The pooled hazard ratios (HR) with 95% confidence interval (CI) were calculated by a fixed-effects model, if no heterogeneity existed. If there was heterogeneity, a random-effects model was applied. The meta-analysis was conducted using the Review Manager 5 software.

RESULTS

A total of 7 articles which included 1629 cases were selected for the meta-analysis. Elevated miR-21 expression was significantly predictive of poor overall survival (HR = 1.51, 95%CI 1.15-1.98, p = 0.003). The subgroup analysis consisted of in tissue sample (HR = 1.66, 95%CI 1.03-2.67, p = 0.04) and serum sample (HR = 1.73, 95%CI 1.22-2.46, p = 0.002). The association between miR-21 expression level and lymph node metastasis was statistically significant (OR = 2.36, 95%CI 1.04-4.78, p = 0.03).

CONCLUSION

Our findings suggest that the circulating miR-21 expression level can predict poor prognosis in patients with breast cancer.

Exploration of the regulatory effect of miR-21 on breast cancer cell line proliferation and invasion as well as the downstream target genes

OBJECTIVE

To study the regulatory effects of miR-21 on breast cancer cell line proliferation and invasion as well as the downstream target genes.

METHODS

Breast cancer cell lines MCF-7 were cultured and transfected with miR-21 mimics and the corresponding negative control mimics (NC mimics), and then MTS kits were used to detect cell viability. Transwell experiment was used to detect cell invasion ability, and fluorescence quantitative PCR was used to detect the expression of proliferation and invasion-related genes in cells.

RESULTS

24 h after transfection of miR-21 mimics and NC mimics, cell OD value and the number of invasive cells of miR-21 group were significantly higher than those of NC group, and mRNA contents of PDCD-4, FasL, PTEN, RhoB, Maspin, TIMP3 and RECK in cells were significantly lower than those of NC group.

CONCLUSION

miR-21 can promote the proliferation and invasion of breast cancer cell lines, and its downstream target genes include PDCD-4, FasL, PTEN, RhoB, Maspin, TIMP3 and RECK.