Knockdown of long noncoding RNA urothelial carcinoma associated 1 inhibits colorectal cancer cell proliferation and promotes apoptosis via modulating autophagy

Long noncoding RNA urothelial carcinoma associated 1 (UCA1) has been implicated in the growth and metastasis of colorectal cancer (CRC), and autophagy contributes to tumorigenesis and cancer cell survival. However, the regulatory role of UCA1 in CRC cell viability by modulating autophagy remains unclear. In the present study, a significant positive correlation was observed between UCA1 and microtubule-associated protein 1 light chain 3 (LC3) levels, and the elevated UCA1 was negatively correlated with the PKB/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway in 293T cells. Downregulation of UCA1 inhibited autophagy activation and cell proliferation, whereas the apoptosis was increased and the cell cycle was arrested in G2 stage. The next results showed that UCA1 was markedly upregulated in Caco-2 cells. Knockdown of UCA1 significantly decreased the LC3-II and autophagy-related gene 5 (ATG5) protein levels and resulted in an increase in p62 expression. Conversely, the autophagy activator rapamycin (RAPA) reversed the effects. Furthermore, downregulated UCA1 decreased Caco-2 cells population in the G1 phase and increased the cells number in G2 phage. The cell proliferation was inhibited, and apoptosis rate was promoted. More important, RAPA could also abrogate the changes induced by knockdown of UCA1. Collectively, these data demonstrated that downregulated UCA1 induced autophagy inhibition, resulting in suppressing cell proliferation and promoting apoptosis, which suggested that UCA1 might serve as a potential new oncogene to regulate CRC cells viability by modulating autophagy.     

Gamma-synuclein promotes cancer cell survival and inhibits stress- and chemotherapy drug-induced apoptosis by modulating MAPK pathways

Synucleins are a family of highly conserved small proteins predominantly expressed in neurons. Recently we and others have found that gamma-synuclein is dramatically up-regulated in the vast majority of late-stage breast and ovarian cancers and that gamma-synuclein over-expression can enhance tumorigenicity. In the current study, we have found that gamma-synuclein is associated with two major mitogen-activated kinases (MAPKs), i.e. extracellular signal-regulated protein kinases (ERK1/2) and c-Jun N-terminal kinase 1 (JNK1), and have shown that over-expression of gamma-synuclein leads to constitutive activation of ERK1/2 and down-regulation of JNK1 in response to a host of environmental stress signals, including UV, arsenate, and heat shock. We also tested the effects of gamma-synuclein on apoptosis and activation of JNK and ERK in response to several chemotherapy drugs. We have found that gamma-synuclein-expressing cells are significantly more resistant to the chemotherapeutic drugs paclitaxel and vinblastine as compared with the parental cells. The resistance to paclitaxel can be partially obliterated when ERK activity is inhibited using a MEK1/2 inhibitor. Activation of JNK and its downstream caspase-3 by paclitaxel or vinblastine is significantly down-regulated in gamma-synuclein-expressing cells, indicating that the paclitaxel- or vinblastine-activated apoptosis pathway is blocked by gamma-synuclein. In contrast to paclitaxel and vinblastine, etoposide does not activate JNK, and gamma-synuclein over-expression has no apparent effect on this drug-induced apoptosis. Taken together, our data indicate that oncogenic activation of gamma-synuclein contributes to the development of breast and ovarian cancer by promoting tumor cell survival under adverse conditions and by providing resistance to certain chemotherapeutic drugs.     

Exosome-transmitted LINC00461 promotes multiple myeloma cell proliferation and suppresses apoptosis by modulating microRNA/BCL-2 expression

Background

Multiple myeloma (MM) is a hematologic cancer caused by the abnormal expansion of plasma cells, but the exact mechanism underlying MM development is not completely known. Recently, multiple long noncoding RNAs (lncRNAs) were implicated in the regulation of MM development.

lncRNA CASC11 promotes cancer cell proliferation in bladder cancer through miRNA-150

Long noncoding RNAs (lncRNAs) CASC11 is an oncogenic lncRNA in gastric cancer and colorectal cancer. Our study aimed to investigate the role of lncRNA CASC11 in bladder cancer. In this study we showed that plasma lncRNA CASC11 was upregulated, while plasma miRNA-150 was downregulated in patients with early-stage bladder cancer than in healthy controls. Altered expression of plasma lncRNA CASC11 and miRNA-150 separated patients with bladder cancer from healthy controls. lncRNA CASC11 expression was inversely correlated with miRNA-150 expression in patients with bladder cance but not in healthy controls. Overexpression of lncRNA CASC11 mediated the inhibition of miRNA-150 expression in cancer cells, while miRNA-150 overexpression did not significantly alter lncRNA CASC11 expression. lncRNA CASC11 overexpression promoted, while miRNA-150 overexpression inhibited cancer cell proliferation. miRNA-150 also attenuated the enhancing effects of lncRNA CASC11 overexpression on cancer cell proliferation. However, overexpression of lncRNA CASC11 showed no significant effects on cancer cell migration and invasion. Therefore, lncRNA CASC11 may promote cancer cell proliferation in bladder cancer, and the actions of lncRNA CASC11 are likely through miRNA-150.     

m6A RNA methylation-mediated NDUFA4 promotes cell proliferation and metabolism in gastric cancer

Gastric cancer (GC) is a malignancy with poor prognosis. NDUFA4 is reported to correlate with the progression of GC. However, its underlying mechanism in GC is unknown. Our study was to reveal the pathogenic mechanism of NDUFA4 in GC. NDUFA4 expression was explored in single-cell and bulk RNA-seq data as well as GC tissue microarray. Mitochondrial respiration and glycolysis were estimated by oxygen consumption rate and extracellular acidification rate, respectively. The interaction between NDUFA4 and METTL3 was validated by RNA immunoprecipitation. Flow cytometry was used to estimate cell cycle, apoptosis and mitochondrial activities. NDUFA4 was highly expressed in GC and its high expression indicated a poor prognosis. The knockdown of NDUFA4 could reduce cell proliferation and inhibit tumor growth. Meanwhile, NDUFA4 could promote glycolytic and oxidative metabolism in GC cells, whereas the inhibition of glycolysis suppressed the proliferation and tumor growth of GC. Besides, NDUFA4 inhibited ROS level and promoted MMP level in GC cells, whereas the inhibition of mitochondrial fission could reverse NDUFA4-induced glycolytic and oxidative metabolism and tumor growth of GC. Additionally, METTL3 could increase the m6A level of NDUFA4 mRNA via the m6A reader IGF2BP1 to promote NDUFA4 expression in GC cells. Our study revealed that NDUFA4 was increased by m6A methylation and could promote GC development via enhancing cell glycolysis and mitochondrial fission. NDUFA4 was a potential target for GC treatment.Subject terms: Gastric cancer, Cancer metabolism     

Long non-coding RNA PVT1-5 promotes cell proliferation by regulating miR-126/SLC7A5 axis in lung cancer

Dysregulated long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) play key roles in the development of human cancers. The lncRNA plasmacytoma variant translocation 1 (PVT1) is reported to be an oncogene in a variety of cancers. However, the roles of PVT1-5 and its related miRNAs in lung cancer are poorly understood. In this study, we found that PVT1-5 expression was significantly increased in lung cancer tissues and cell lines. By using biotin-labeled lncRNA-PVT1-5 probe for miRNA in vivo precipitation (miRIP) in lung cancer cells and dual-luciferase reporterassays, we identified that miR-126 was associated with lncRNA-PVT1-5. Furthermore, knockdown of lncRNA-PVT1-5 in cells could down-regulate the expression of SLC7A5, the target of oncogenic miR-126, resulting in the cell proliferation. Conversely, inhibiting the expression of miR-126 markedly increased the expression of SLC7A5 and alleviated cell proliferation inhibition. Thus, our results indicated that lncRNA-PVT1-5 may function as a competing endogenous RNA (ceRNA) for miR-126 to promote cell proliferation by regulating the miR-126/SLC7A5 pathway, suggesting that lncRNA-PVT1-5 plays a crucial role in lung cancer progression and lncRNA-PVT1-5/miR-126/SLC7A5 regulatory network may shed light on tumorigenesis in lung cancer.     

Long intergenic noncoding RNA 00908 promotes proliferation and inhibits apoptosis of colorectal cancer cells by regulating KLF5 expression

Long intergenic noncoding RNAs (lincRNAs) play a vital role in the occurrence and progression of cancer. The mechanism of lincRNAs in colorectal cancer (CRC) has not been fully elucidated. In this context, an integrated comparative long noncoding RNA (lncRNA) microarray technology was used to determine the expression profile of lncRNAs in CRC. The roles of LINC00908 are unclear. We found that LINC00908 was significantly upregulated in CRC. Inhibition of LINC00908 resulted in reduced cell proliferation and G1 cell cycle arrest, which was mediated by cyclin D1, cyclin‐dependent kinase 4, and phosphorylated retinoblastoma. Moreover, inhibition of LINC00908‐induced apoptosis through the intrinsic apoptosis signaling pathway, as shown by the activation of caspase‐9 and caspase‐3. Mechanistically, miR‐143‐3p directly bound to LINC00908. miR‐143‐3p expression was negatively correlated with LINC00908 expression in CRC tissue. Functional experiments revealed opposing roles for miR‐143‐3p and LINC00908, suggesting that LINC00908 negatively regulates miR‐143‐3p. Mechanistically, miR‐143‐3p directly targets LINC00908. The KLF5 inhibitor ML264 affected proliferation and apoptosis, indicating that LINC00908 may act as a competing endogenous RNA to facilitate the expression of the miR‐143‐3p target gene KLF5. Thus, LINC00908 has an important proliferative and antiapoptotic role in CRC by regulating the cell cycle and intrinsic apoptosis. LINC00908 could be a potential biomarker and a new therapeutic target for CRC.     

Long non‐coding RNA 00312 regulated by HOXA5 inhibits tumour proliferation and promotes apoptosis in Non‐small cell lung cancer

Non‐small cell lung cancer (NSCLC) is the most prevalent type of lung cancer. The abnormal expression of many long non‐coding RNAs (lncRNAs) has been reported involved in the progression of various tumours, which can be used as diagnostic indicators or antitumour targets. Here, we found that the long non‐coding RNA 00312 was down‐regulated in paired NSCLC tissues and correlated with poor clinical outcome; decreased linc00312 expression in NSCLC was associated with larger and later stage tumours. Functional experiments showed that linc00312 could inhibit cell proliferation and promote apoptosis in vitro and in vivo. Furthermore, we found that HOXA5 could bind in the promoter of linc00312 and up‐regulated the expression of it. Moreover, linc00312 was down‐regulated in the plasma of NSCLC patients compared with that of healthy volunteers or other pulmonary diseases patients. Taken together, our findings indicated that linc00312 could be a novel diagnosis biomarker and a promising therapeutic target for NSCLC.     

SOCS1 counteracts ROS-mediated survival signals and promotes apoptosis by modulating cell cycle to increase radiosensitivity of colorectal cancer cells

As negative regulators of cytokine signaling pathways, suppressors of cytokine signaling (SOCS) proteins have been reported to possess both pro-tumor and anti-tumor functions. Our recent studies have demonstrated suppressive effects of SOCS1 on epithelial to mesenchymal signaling in colorectal cancer cells in response to fractionated ionizing radiation or oxidative stress. The objective of the present study was to determine the radiosensitizing action of SOCS1 as an anti-tumor mechanism in color-ectal cancer cell model. In HCT116 cells exposed to ionizing radiation, SOCS1 over-expression shifted cell cycle arrest from G2/M to G1 and promoted radiation-induced apoptosis in a p53-dependent manner with down-regulation of cyclin B and up-regulation of p21. On the other hand, SOCS1 knock-down resulted in a reduced apoptosis with a decrease in G1 arrest. The regulatory action of SOCS1 on the radiation response was mediated by inhibition of radiation-induced Jak3/STAT3 and Erk activities, thereby blocking G1 to S transition. Radiation-induced early ROS signal was responsible for the activation of Jak3/Erk/STAT3 that led to cell survival response. Our data col-lectively indicate that SOCS1 can promote radiosensitivity of colorectal cancer cells by counteracting ROS-mediated survival signal, thereby blocking cell cycle progression from G1 to S. The resulting increase in G1 arrest with p53 activation then contributes to the promotion of apoptotic response upon radiation. Thus, induction of SOCS1 expression may increase therapeutic efficacy of radiation in tumors with low SOCS1 levels.     

Activation of type 4 metabotropic glutamate receptor promotes cell apoptosis and inhibits proliferation in bladder cancer

Bladder cancer, the second most common genitourinary malignancy, severely endangers the human health. Rising evidence suggests that metabotropic glutamate receptors (mGluRs) are involve in tumor progression. In this study, we observed that metabotropic glutamate receptor 4 (mGluR4) was functionally expressed in normal and cancerous bladder cells and its expression was positively correlated with high bladder cancer grading. We further confirmed that the activation of mGluR4 by VU0155041, an mGluR4-specific agonist, decreased cyclic adenosine monophosphate (cAMP) concentration and cell viability, promoted apoptosis and inhibited proliferation in bladder cancer cells, whereas MSOP (group III mGluR antagonist) or mGluR4 knockdown eliminated the effects of mGluR4 activity. Western blotting revealed the decreased cyclin D1 expression, increased procaspase-8/9/3 cleavage, and unbalanced Bcl-2/Bax expression in bladder cancer cell lines after mGluR4 activation, and likewise MSOP and mGluR4 knockdown abrogated the actions of mGluR4 activity. In vivo study showed that mGluR4 activation significantly inhibited tumor growth of bladder cancer via suppressing proliferation and promoting apoptosis. Furthermore, upregulation of phosphatase and tensin homolog (PTEN) and inhibition of Akt phosphorylation were also observed after mGluR4 activation. Similar with VU0155041, the Akt-specific inhibitor markedly promoted apoptosis and inhibited proliferation. Nevertheless, the PTEN-specific inhibitor significantly abolished the mGluR4 activation-induced cell apoptosis and proliferative inhibition in bladder cancer cell lines. These results indicate that mGluR4 can regulate the switch between survival and death via the cAMP/PTEN/AKT signaling pathway in bladder cancer cells. Our findings suggest that mGluR4 has diagnostic and prognostic potential for bladder cancer, and the development of mGluR4 agonist may be a promising strategy for bladder cancer treatment.     

Circular RNA circ_0103552 forecasts dismal prognosis and promotes breast cancer cell proliferation and invasion by sponging miR-1236

Breast cancer (BC) is a fatal malignancy, which has a high incidence and mortality across the world. Circular RNAs (circRNAs) have crucial roles in tumor initiation and progression. In this project, a newly found circRNA, circ_0103552 was explored. Quantitative real-time polymerase chain reaction was applied to measure its expression in the patients' tissue specimens and cells. In addition, Fisher's exact test, Kaplan-Meier curves and Cox regression model were conducted to discover the clinical significance of circ_0103552. Cell viability, clone-forming ability, apoptosis, and metastatic properties of BC cells were evaluated by gain/loss-of-function assays. Dual luciferase reporter assay was applied to illuminate its mechanisms. As data indicated, circ_0103552 was significantly elevated in BC tissue samples and cells. In addition, its expression correlates with clinical severity and dismal prognosis. Furthermore, circ_0103552 could facilitate cell growth, clone-forming ability, migration and invasion, and decrease apoptotic cells. For the mechanism exploration, circ_0103552 could directly sponge miR-1236 to execute oncogenic activities in BC cells. In summary, this study provides a novel circRNA in tumorigeneis and progression of BC and may help to develop effective therapeutic target for this devastating disease.     

miR-301a promotes pancreatic cancer cell proliferation by directly inhibiting bim expression

It is well known that microRNAs (miRNAs) play an important role in many diseases, including tumorigenesis. However, the mechanisms by which miRNAs regulate pancreatic cancer (PC) development remain poorly understood. In the present study, we assayed expression level of miR‐301a in PC tissues by real‐time PCR, and defined the target gene and biological function by luciferase reporter assay and Western blot analysis. We first verified that the expression level of miR‐301a was significantly increased in PC tissues. Moreover, miR‐301a overexpression promoted PC cell proliferation, whereas its depletion decreased cell proliferation. We further demonstrated that miR‐301a directly targeted 3′‐UTR of Bim gene, and inhibited its protein expression in vitro and in vivo. Importantly, Bim re‐expression reduced PC cell proliferation induced by miR‐301a. These data suggest an important role of miR‐301a in the molecular etiology of PC and implicate the potential application of miR‐301a in PC therapy. J. Cell. Biochem. 113: 3229–3235, 2012. © 2012 Wiley Periodicals, Inc.     

Circular RNA circBCBM1 promotes breast cancer brain metastasis by modulating miR-125a/BRD4 axis

Circular RNAs (circRNAs) play critical roles in tumorigenesis and the progression of various cancers. We previously identified a novel upregulated circRNA, circBCBM1 (hsa_circ_0001944), in the context of breast cancer brain metastasis. However, the potential biological function and molecular mechanism of circBCBM1 in breast cancer brain metastasis remain largely unknown. In this study, we confirmed that circBCBM1 was a stable and cytoplasmic circRNA. Functionally, circBCBM1 promoted the proliferation and migration of 231-BR cells in vitro and growth and brain metastasis in vivo. Mechanistically, circBCBM1 acted as an endogenous miR-125a sponge to inhibit miR-125a activity, resulting in the upregulation of BRD4 (bromodomain containing 4) and subsequent upregulation of MMP9 (matrix metallopeptidase 9) through Sonic hedgehog (SHH) signaling pathway. Importantly, circBCBM1 was markedly upregulated in the breast cancer brain metastasis cells and clinical tissue and plasma samples; besides, circBCBM1 overexpression in primary cancerous tissues was associated with shorter brain metastasis-free survival (BMFS) of breast cancer patients. These findings indicate that circBCBM1 is involved in breast cancer brain metastasis via circBCBM1/miR-125a/BRD4 axis. CircBCBM1 may serve as a novel diagnostic and prognostic biomarker and potential therapeutic target for breast cancer brain metastasis.     

Long non-coding RNA LINC00460 promotes proliferation and inhibits apoptosis of cervical cancer cells by targeting microRNA-503-5p

Molecular and Cellular Biochemistry - We reported previously that the rat submandibular gland is able to release nanovesicles capable to hydrolyse millimolar concentrations of ATP, ADP and AMP in...     

Retracted: Sapylin inhibits lung cancer cell proliferation and promotes apoptosis by attenuating PI3K/AKT signaling

Sapylin (OK-432) revealed biological properties in cancers. In this study, the effect of sapylin on lung cancer cell A549 was investigated. A549 cell lines were treated with sapylin (0.1, 0.5, and 1 KE/mL) for different time intervals. A549 cell proliferation and apoptosis was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide/Ki67 assay and flow cytometry, respectively. Western blot was used to determine the expressions of proteins involved in proliferation, apoptosis, and phosphoinositide 3-kinase/serine/threonine kinase (PI3K/AKT), Wnt3a/β-catenin signaling pathway. Level of intracellular reactive oxygen species (ROS) was insured by using the ROS kit. Sapylin inhibited A549 cell viability and the expressions of proliferation-related proteins (cyclin E1 and D1) in dose- and time-dependent manners. Sapylin promoted apoptosis in a dose- and time-dependent manners. Sapylin also promoted the expressions of apoptotic proteins (cleaved caspase-3 and 8) in dose- and time-dependent manners. Furthermore, sapylin increased the intracellular concentration of ROS in a dose-dependent manner. Besides, the high expression of ROS level might induce inhibition of cell viability and increase cell apoptosis. The mechanistic study revealed that sapylin inactivated the PI3K/AKT and Wnt3a/β-catenin signaling pathways. Our findings suggest that sapylin inhibits proliferation and promotes apoptosis in lung cancer cells, thus providing a new theoretical basis for the treatment of lung cancer.