Cromolyn chitosan nanoparticles reverse the DNA methylation of RASSF1A and p16 genes and mitigate DNMT1 and METTL3 expression in breast cancer cell line and tumor xenograft model in mice.

BACKGROUND: Developing epigenetic drugs for breast cancer (BC) remains a novel therapeutic approach. Cromolyn is a mast cell stabilizer emerging as an anticancer drug; its encapsulation in chitosan nanoparticles (CSNPs) improves its effect and bioavailability. However, its effect on DNA and RNA methylation machineries has not been previously tackled. METHODS: The possible anticancer effect of cromolyn CSNPs and its potential as an epigenetic drug was investigated in vitro using MCF-7 human BC cell line and in vivo using Ehrlich ascites carcinoma-xenograft model in mice symbolizing murine mammary adenocarcinoma. Mice were injected with a single dose of Ehrlich ascites carcinoma cells subcutaneously for the induction of tumor mass, and then randomized into three groups: control, cromolyn CSNPs (equivalent to 5 mg cromolyn/kg, i.p.) and plain CSNPs twice/week for 2 weeks. RESULTS: Cromolyn CSNPs showed prominent anticancer effect in MCF-7 cells by reducing the cell viability percent and enhancing DNA damage in the comet assay demonstrating its apoptotic actions. Mechanistically, cromolyn CSNPs influenced potential epigenetic processes through mitigating DNA methyltransferase 1 (DNMT1) expression, reversing the hypermethylation pattern of the tumor suppressor RASSF1A and p16 genes and attenuating the expression of the RNA N6-methyladenosine writer, methyltransferase-like 3 (METTL3). Cromolyn CSNPs diminished ERK1/2 phosphorylation, a possible arm influencing DNMT1 expression. In vivo, cromolyn CSNPs lessened the tumor volume and halted DNMT1 and METTL3 expression in Ehrlich carcinoma mice. CONCLUSIONS: Cromolyn CSNPs have the premise as an epigenetic drug through inhibiting ERK1/2 phosphorylation/DNMT1/DNA methylation and possibly impacting the RNA methylation machinery via mitigating METTL3 expression.

LINC01116 Promotes Migration and Invasion of Oral Squamous Cell Carcinoma by Acting as a Competed Endogenous RNA in Regulation of MMP1 Expression.

Oral squamous cell carcinoma (OSCC) has increasingly become a worldwide health concern, and its survival rate has not been much improved partially due to a deficiency of precise molecular markers. Dysregulation of LINC01116, a long noncoding RNA sequence, has been observed in several types of cancer. However, the role played by LINC01116 in OSCC has not yet been fully elaborated. This study explored how LINC01116 was involved in the regulation of OSCC progression by analyzing expressions of LINC01116 in OSCC patients. The findings demonstrated upregulation of LINC01116 in OSCC tissues as opposed to regular oral mucosa, and overexpression of LINC01116 was correlated with advanced tumor status. LINC01116 knockdown using shRNA markedly reduced the OSCC cell invasion and migration in vitro. Moreover, the expression of LINC01116 was negatively correlated with that of microRNA-9-5p (miR-9). Luciferase reporter and loss-of-function assays demonstrated that LINC01116 functioned as a competing endogenous RNA (ceRNA) that could effectively sponge miR-9, thus regulating the derepression of matrix metalloproteinase 1 (MMP1). Furthermore, we confirmed that LINC01116 knockdown did not affect the expression of MMP1 messenger RNA (mRNA). Collectively, it is demonstrated in this study that overexpression of LINC01116 can promote the OSCC progression. The LINC01116-miR-9-MMP1 axis provides a novel insight into the OSCC pathogenesis and offers potential therapeutic targets against OSCC.

Exosome-derived miR-200a promotes esophageal cancer cell proliferation and migration via the mediating Keap1 expression.

Previous studies have reported that exosomes bearing certain microRNAs (miRNAs) are related to the physiological functions of different types of cancer cells. Our study aimed to elucidate the role of miR-200a in esophageal squamous cell carcinoma (ESCC). We observed that miR-200a expression is higher in esophageal carcinoma cells, tissues, and exosomes than in normal cells and healthy tissues. We showed that exosome-shuttled miR-200a promotes the proliferation, migration, and invasion of esophageal cells and inhibits apoptosis, thereby leading to the progression of ESCC. We showed that miR-200a exerts its effects through its interaction with Keap1, thus altering the Keap1/Nrf2 signaling pathway. Our results suggest that exosome-shuttled miR-200a might be useful as a biomarker for prognosis in patients with ESCC.

The Role of Exosomal Non-Coding RNAs in Colorectal Cancer Drug Resistance.

BACKGROUND: Colorectal cancer (CRC) is one of the most common types of cancer diagnosed worldwide with high morbidity; drug resistance is often responsible for treatment failure in CRC. Non-coding RNAs (ncRNAs) play distinct regulatory roles in tumorigenesis, cancer progression and chemoresistance. METHODS: A literature search was conducted in PubMed database in order to sum up and discuss the role of exosomal ncRNAs (ex-ncRNAs) in CRC drug resistance/response and their possible mechanisms. RESULTS: Thirty-six (36) original research articles were identified; these included exosome or extracellular vesicle (EV)-containing microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and small-interfering (siRNAs). No studies were found for piwi-interacting RNAs. CONCLUSIONS: Exosomal transfer of ncRNAs has been documented as a new mechanism of CRC drug resistance. Despite being in its infancy, it has emerged as a promising field for research in order to (i) discover novel biomarkers for therapy monitoring and/or (ii) reverse drug desensitization.

miR-182 targeting reprograms tumor-associated macrophages and limits breast cancer progression.

The protumor roles of alternatively activated (M2) tumor-associated macrophages (TAMs) have been well established, and macrophage reprogramming is an important therapeutic goal. However, the mechanisms of TAM polarization remain incompletely understood, and effective strategies for macrophage targeting are lacking. Here, we show that miR-182 in macrophages mediates tumor-induced M2 polarization and can be targeted for therapeutic macrophage reprogramming. Constitutive miR-182 knockout in host mice and conditional knockout in macrophages impair M2-like TAMs and breast tumor development. Targeted depletion of macrophages in mice blocks the effect of miR-182 deficiency in tumor progression while reconstitution of miR-182-expressing macrophages promotes tumor growth. Mechanistically, cancer cells induce miR-182 expression in macrophages by TGFß signaling, and miR-182 directly suppresses TLR4, leading to NFκb inactivation and M2 polarization of TAMs. Importantly, therapeutic delivery of antagomiR-182 with cationized mannan-modified extracellular vesicles effectively targets macrophages, leading to miR-182 inhibition, macrophage reprogramming, and tumor suppression in multiple breast cancer models of mice. Overall, our findings reveal a crucial TGFß/miR-182/TLR4 axis for TAM polarization and provide rationale for RNA-based therapeutics of TAM targeting in cancer.

Nuclear genome-derived circular RNA circPUM1 localizes in mitochondria and regulates oxidative phosphorylation in esophageal squamous cell carcinoma.

Circular RNAs (circRNAs) were shown to play an important role in the occurrence and progression of tumors. However, the functions of nuclear genome-derived circRNAs localized in mitochondria of tumor cells remain largely elusive. Here, we report that circPUM1, a circular RNA derived from back-splicing of pre-mRNAs of nuclear genome PUM1, localizes in mitochondria. The expression level of circPUM1 is positively correlated with HIF1α accumulation under CoCl2-induced intracellular hypoxic-like condition in esophageal squamous cell carcinoma (ESCC) cell lines. Importantly, circPUM1 acts as a scaffold for the interaction between UQCRC1 and UQCRC2 in ESCC cell lines. Knock-down of circPUM1 would result in lower intracellular oxygen concentration, downregulated oxidative phosphorylation, decrease of mitochondrial membrane potential, increase of ROS generation and shrinking of mitochondria, respectively. CircPUM1 depletion induces dysfunction of the mitochondrial complex III and the cleavage of caspase3 spontaneously. Interestingly, disruption of circPUM1 led to pyroptosis that initiates the cell death of ESCC cell lines. Therefore, we conclude that circPUM1 plays a critical role in maintaining the stability of mitochondrial complex III to enhance oxidative phosphorylation for ATP production of ESCC cells and moreover propose that ESCC cells exploit circPUM1 during cell adaptation.

Analyses of human cancer driver genes uncovers evolutionarily conserved RNA structural elements involved in posttranscriptional control.

Experimental breakthroughs have provided unprecedented insights into the genes involved in cancer. The identification of such cancer driver genes is a major step in gaining a fuller understanding of oncogenesis and provides novel lists of potential therapeutic targets. A key area that requires additional study is the posttranscriptional control mechanisms at work in cancer driver genes. This is important not only for basic insights into the biology of cancer, but also to advance new therapeutic modalities that target RNA-an emerging field with great promise toward the treatment of various cancers. In the current study we performed an in silico analysis on the transcripts associated with 800 cancer driver genes (10,390 unique transcripts) that identified 179,190 secondary structural motifs with evidence of evolutionarily ordered structures with unusual thermodynamic stability. Narrowing to one transcript per gene, 35,426 predicted structures were subjected to phylogenetic comparisons of sequence and structural conservation. This identified 7,001 RNA secondary structures embedded in transcripts with evidence of covariation between paired sites, supporting structure models and suggesting functional significance. A select set of seven structures were tested in vitro for their ability to regulate gene expression; all were found to have significant effects. These results indicate potentially widespread roles for RNA structure in posttranscriptional control of human cancer driver genes.

MiR-369-5p inhibits the proliferation and migration of hepatocellular carcinoma cells by down-regulating HOXA13 expression.

MicroRNA (miRNA) is vital to the progression of hepatocellular carcinoma (HCC). Thereinto, miR-369-5p could yield assorted effects on various cancers, but there are few reports concerning the effect of miR-369-5p on HCC. Thus this study aimed to investigate the effect and mechanism of miR-369-5p in HCC. The data of miR-369-5p and HOXA13 expressions in liver hepatocellular carcinoma (LIHC) were analyzed by starBase, and then the miR-369-5p expression in HCC tissues and cells was detected by quantitative real-time PCR. Subsequently, miR-369-5p mimic was transfected into HCC cells and then its effects on cell activities were evaluated by cell counting kit-8, colony formation, wound healing, transwell assays, respectively. Expressions of epithelial-mesenchymal transition (EMT)-related genes were determined by western blot. The targeting relationship between miR-369-5p and HOXA13 was predicted by Targetscan and verified by dual-luciferase reporter assay. Pearson correlation test was used to analyze the correlation between HOXA13 and miR-369-5p. The above assays were experimented again to investigate the effects of HOXA13 on biological activity and EMT of HCC cells. MiR-369-5p expression was down-regulated and HOXA13 expression was up-regulated in LIHC. MiR-369-5p targeted HOXA13 and the expression of miR-369-5p was negatively correlated with the HOXA13 expression. MiR-369-5p inhibited the viability, proliferation, migration and invasion of HCC cells, increased E-cadherin level and decreased N-cadherin and Vimentin expressions. Concurrently, HOXA13 overexpression could counteract the effects of miR-369-5p on biological activity and EMT-related biomarkers of HCC cells. To conclude, miR-369-5p inhibits the viability, proliferation, migration and invasion of HCC cells by repressing the expression of HOXA13.

The LOXL1 antisense RNA 1 (LOXL1-AS1)/microRNA-423-5p (miR-423-5p)/ectodermal-neural cortex 1 (ENC1) axis promotes cervical cancer through the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway.

As the fourth commonest malignancy among females worldwide, cervical cancer (CC) poses a huge challenge to human health. The pivotal regulatory roles of lncRNAs in cancers have been highlighted. LOXL1 antisense RNA 1 (LOXL1-AS1) has been reported to play a key role in cervical squamous cell carcinoma and other various cancers. Thus, we investigated the roles and mechanisms of lncRNA LOXL1-AS1 in CC. The in vivo experiments demonstrated that LOXL1-AS1 downregulation inhibited tumor growth and metastasis and proliferation of CC cells. The results of RT-qPCR demonstrated that LOXL1-AS1 and ectodermal-neural cortex 1 (ENC1) expression levels were upregulated in CC cells and tissues, while microRNA-423-5p (miR-423-5p) level was downregulated. As subcellular fractionation assays, RNA pull down assays and luciferase reporter assays revealed, LOXL1-AS1 bound to miR-423-5p and miR-423-5p targeted ENC1. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, wound healing and colony formation assays demonstrated that miR-423-5p upregulation and LOXL1-AS1 downregulation inhibited CC cell proliferation and migration, while ENC1 upregulation attenuated the inhibitory effects of miR-423-5p upregulation on the malignant phenotypes of CC cells. Western blotting was conducted to measure protein levels and the results showed that ENC1 knockdown inhibited the activation of ERK/MEK pathway. In summary, the LOXL1-AS1/miR-423-5p/ENC1 axis accelerates CC development through the MEK/ERK pathway.

Zinc finger protein 277 is an intestinal transit-amplifying cell marker and colon cancer oncogene.

Sustained proliferative signaling and resisting cell death are hallmarks of cancer. Zinc finger protein 277 (ZNF277; murine Zfp277), a transcription factor regulating cellular senescence, is overexpressed in colon cancer, but its actions in intestinal homeostasis and neoplasia are unclear. Using human and murine intestine, human colon cancer cells, and ApcMin/+ mice with dysregulated ß-catenin signaling and exuberant intestinal neoplasia, we explored the actions of ZNF277/Zfp277 and defined the underlying mechanisms. In normal human and murine intestine, ZNF277/Zfp277 was expressed uniquely in early stem cell progenitors, undifferentiated transit-amplifying cells (TACs). Zfp277 was overexpressed in the ApcMin/+ mouse colon, implicating ZNF277/Zfp277 as a transcriptional target of ß-catenin signaling. We confirmed this by showing ß-catenin knockdown reduced ZNF277 expression and, using chromatin IP, identified 2 ß-catenin binding sites in the ZNF277 promoter. Zfp277 deficiency attenuated intestinal epithelial cell proliferation and tumor formation, and it strikingly prolonged ApcMin/+ mouse survival. RNA-Seq and PCR analyses revealed that Zfp277 modulates expression of genes in key cancer pathways, including ß-catenin signaling, the HOXD family that regulates development, and p21WAF1, a cell cycle inhibitor and tumor suppressor. In both human colon cancer cells and the murine colon, ZNF277/Zfp277 deficiency induced p21WAF1 expression and promoted senescence. Our findings identify ZNF277/Zfp277 as both a TAC marker and colon cancer oncogene that regulates cellular proliferation and senescence, in part by repressing p21WAF1 expression.

LncRNAs LCETRL3 and LCETRL4 at chromosome 4q12 diminish EGFR-TKIs efficiency in NSCLC through stabilizing TDP43 and EIF2S1.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are effective targeted therapy drugs for advanced non-small cell lung cancer (NSCLC) patients carrying sensitized EGFR mutations. The rapid development of EGFR-TKIs resistance represents a major clinical challenge for managing NSCLC. The chromosome 4q12 is the first genome-wide association study (GWAS)-reported locus associated with progression-free survival (PFS) of NSCLC patients treated with EGFR-TKIs. However, the biological significance of the noncoding transcripts at 4q12 in NSCLC remains elusive. In the present study, we identified two 4q12 long noncoding RNAs (lncRNAs) LCETRL3 and LCETRL4 which could significantly dimmish EGFR-TKIs efficiency. In line with their oncogenic role, evidently higher LCETRL3 and LCETRL4 levels were observed in NSCLC tissues as compared with normal specimens. Importantly, lncRNA LCETRL3 can interact with oncoprotein TDP43 and inhibit ubiquitination and degradation of TDP43. Similarly, lncRNA LCETRL4 can bind and stabilize oncoprotein EIF2S1 through reducing ubiquitin-proteasome degradation of EIF2S1. In particular, elevated levels of LCETRL3 or LCETRL4 in NSCLC cells resulted in stabilization of TDP43 or EIF2S1, increased levels of NOTCH1 or phosphorylated PDK1, activated AKT signaling and, thus, EGFR-TKIs resistance. Taken together, our data revealed a novel model that integrates two lncRNAs transcribed from the 4q12 locus into the regulation of EGFR-TKIs resistance in NSCLC. These findings shed new light on the importance of functionally annotating lncRNAs in the GWAS loci and provided insights to declare novel druggable targets, i.e., lncRNAs, which may unlock the therapeutic potential of EGFR-TKIs resistant NSCLC in the clinic.

LncRNA PVT1 facilitates DLBCL development via miR-34b-5p/Foxp1 pathway.

Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of non-Hodgkin lymphoma and is a very aggressive malignancy with tumor growing rapidly in organs like lymph nodes. The pathogenesis of DLBCL is not clear and the prognosis of DLBCL requires improvement. Here, we investigated the mechanisms of DLBCL, with the focus on lncRNA PVT1/miR-34b-5p/Foxp1 axis. Human DLBCL tissues from diagnosed DLBCL patients and four human DLBCL cell lines, one normal human B lymphoblastoid cell line were used. qRT-PCR and western blotting were employed to measure expression levels of lncRNA PVT1, Foxp1, miR-34b-5p, ß-catenin, and proliferation-related proteins. MTT assay and colony formation assay were performed to determine cell proliferation. Flow cytometry was used to examine cell apoptosis. ChIP and Dual-luciferase assay were utilized to validate interactions of Foxp1/promoters, PVT1/miR-34b-5p and miR-34b-5p/Foxp1. Mouse tumor xenograft model was used to determine the effect of sh-PVT1 on tumor growth in vivo. In this study, we found PVT1 and Foxp1 were elevated in DLBCL tissues and cells while miR-34b-5p was decreased. Knockdown of PVT1, overexpression of miR-34b-5p, or Foxp1 knockdown repressed DLBCL cell proliferation but enhanced cell apoptosis. PVT1 directly bound miR-34b-5p to disinhibit Foxp1/ß-catenin signaling. Foxp1 regulated CDK4, CyclinD1, and p53 expression via binding with their promoters. Knockdown of Foxp1 partially reversed the effects of miR-34b-5p inhibitor on DLBCL cell proliferation and apoptosis. Inhibition of PVT1 through shRNA suppressed DLBCL tumor growth in vivo. All in all, lncRNA PVT1 promotes DLBCL progression via acting as a miR-34b-5p sponge to disinhibit Foxp1/ß-catenin signaling.

Processing body (P-body) and its mediators in cancer.

In recent years, processing bodies (P-bodies) formed by liquid-liquid phase separation, have attracted growing scientific attention due to their involvement in numerous cellular activities, including the regulation of mRNAs decay or storage. These cytoplasmic dynamic membraneless granules contain mRNA storage and decay components such as deadenylase and decapping factors. In addition, different mRNA metabolic regulators, including m6A readers and gene-mediated miRNA-silencing, are also associated with such P-bodies. Cancerous cells may profit from these mRNA decay shredders by up-regulating the expression level of oncogenes and down-regulating tumor suppressor genes. The main challenges of cancer treatment are drug resistance, metastasis, and cancer relapse likely associated with cancer stem cells, heterogeneity, and plasticity features of different tumors. The mRNA metabolic regulators based on P-bodies play a great role in cancer development and progression. The dysregulation of P-bodies mediators affects mRNA metabolism. However, less is known about the relationship between P-bodies mediators and cancerous behavior. The current review summarizes the recent studies on P-bodies mediators, their contribution to tumor development, and their potential in the clinical setting, particularly highlighting the P-bodies as potential drug-carriers such as exosomes to anticancer in the future.

Noncoding RNAs and hyperthermic intraperitoneal chemotherapy in advanced gastric cancer.

Gastric cancer (GC) is one of the most common malignant tumors globally. About 20-30% of patients with gastric cancer show peritoneal implantation metastasis at the first diagnosis. Peritoneal metastasis is responsible for 70% of deaths of patients with advanced gastric cancer. Although there are many ways to treat advanced gastric cancer, the prognosis of patients with recurrence is unsatisfactory. An auxiliary treatment with hyperthermic intraperitoneal chemotherapy (HIPEC), is an internationally recognized recommended treatment for advanced gastric cancer. A series of clinical trials have shown that HIPEC significantly improves the overall survival of patients with cancer. Compared with the cytoreductive surgery (CRS) alone, HIPEC combined with CRS markedly reduced the rate of peritoneal metastasis in patients with ovarian cancer and colorectal cancer. It has been demonstrated that HIPEC alters transcription of many genes by affecting non-coding RNAs, which may contribute to the suppressive effect of HIPEC on the synthesis of nucleic acids and proteins in cancer cells. This paper reviews the recent advances in understanding the role of non-coding RNAs in tumor invasion and metastasis of advanced gastric cancer. We also consider changes in noncoding RNA levels and other molecules in advanced gastric cancer cases treated with HIPEC. We hope that our review will provide a reference for future research on molecular epidemiology and etiology of advanced gastric cancer and promote precise treatment of this malignancy using HIPEC.

miR-183-5p promotes proliferation, invasion, and glycolysis of thyroid carcinoma cells by targeting FOXO1.

The aim of this study was to research the influences of miR-183-5p on the proliferation, invasion, and glycolysis of thyroid cancer (THCA) cells. Clinical specimens from 84 THCA patients were included. THCA cell lines (K1, SW1736, and TPC1) were cultured. siFOXO1, miR-183-5p mimic, or miR-183-5p inhibitors were transfected into THCA cells by Lipofectamine ™ 2000. qRT-PCR, western blot, and immunohistochemistry assays were used to detect miR-183-5p and FOXO1 expression. CCK-8 assay, colony formation, flow cytometry, Transwell, and wound healing experiment were utilized, respectively, to detect cell proliferation, colony formation, apoptosis, invasion, and migration. Glycolysis was evaluated by detecting glucose uptake, lactate production, ATP level, and glycolysis-related proteins expression. Dual-luciferase reporter assay and RNA pull-down assay were employed to verify the target relationship between miR-183-5p and FOXO1. The effect of miR-183-5p on THCA cells growth in vivo was researched using nude mice. miR-183-5p was highly expressed in THCA tissues and cells, correlating with poor outcome. miR-183-5p up-regulation attenuated apoptosis, and accelerated proliferation, colony formation, migration, invasion, and glycolysis of THCA cells. Opposite results were found by miR-183-5p down-regulation. FOXO1 was a target gene of miR-183-5p, where expression was directly inhibited by miR-183-5p. FOXO1 silencing reversed the inhibitory effect of miR-183-5p inhibitor on THCA cells malignant phenotype. miR-183-5p down-regulation inhibited THCA cells growth in vivo. miR-183-5p accelerates progression and glycolysis of THCA by targeting FOXO1. miR-183-5p was a novel target for THCA treatment.

MicroRNA-656-3p inhibits colorectal cancer cell migration, invasion, and chemo-resistance by targeting sphingosine-1-phosphate phosphatase 1.

Colorectal cancer presents high rates of recurrence and metastasis, and the occurrence and progression and mechanism of its invasion and metastasis are not fully understood. The expression of miR-656-3p in patient samples and 10 cell lines were measured. Bioinformatic databases were used to predict miRNAs. Protein expressions were examined using Western blot. Transwell assay was used to measure cell migration and invasion. Transplanted tumor model in nude mice was established. Removal of the miR-656-3p by specific knocking-down of this gene promoted the chemo-resistance of colorectal cancer cells. Critically, we identified sphingosine-1-phosphate phosphatase 1 (SGPP1) as a downsteam target of the miR-656-3p, which we first obtained from 199 potential target genes from Targetscan, 200 genes from miRDB and 200 genes from DIANA, respectively. Then, we identified the interaction between SGPP1 and the miR-656-3p on 3' UTR of SGPP1 gene. Knockdown of SGPP1 greatly suppressed the tumor growth in vivo and epithelial mesenchymal transition process. miR-656-3p could regulate cell proliferation and chemoresistance in the colorectal cancer that associate to downstream target with SGPP1. Along with its downstream molecule, we would like to predict that the SGPP1 associated miR-656-3p could be used to develop early for early diagnostics for CRC oncogenesis.

Circular RNA lysophosphatidic acid receptor 3 (circ-LPAR3) enhances the cisplatin resistance of ovarian cancer.

Circular RNA (circRNA) is considered to be an important regulator that mediates cancer chemoresistance. But whether circ-LPAR3 is involved in ovarian cancer (OC) cisplatin (DDP) resistance is unclear. The circ-LPAR3, miR-634 and pyruvate dehydrogenase kinase 1 (PDK1) expression was measured by quantitative real-time PCR (qRT-PCR). Cell cisplatin resistance and viability were measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay. In addition, cell colony number, apoptosis, and metastasis were assessed by colony formation assay, flow cytometry and transwell assay. Furthermore, in vivo experiments were performed by constructing mice xenograft models. RNA interaction was confirmed by dual-luciferase reporter assay, and PDK1 protein expression was examined by Western blot analysis. Our results showed that circ-LPAR3 was markedly upregulated in DDP-resistant OC tissues and cells. Silencing of circ-LPAR3 enhanced the DDP sensitivity of OC cells and tumors. MiR-634 could interact with circ-LPAR3, and its inhibitor overturned the regulation of si-circ-LPAR3 on cell DDP resistance. Additionally, PDK1 was targeted by miR-634, and its overexpression inverted the effect of miR-634 on cell DDP resistance. To sum up, circ-LPAR3 might contribute to the DDP resistance of OC via the miR-634/PDK1 axis.

Hsa_circ_0006677 regulates special AT-rich binding protein-2-mediated tumor-suppressive effect via functioning as a miR-1245a sponge in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is still one of the most challenging malignant tumors. Deregulation of circular RNAs (circRNAs) is associated with NSCLC progression. However, the regulatory mechanism of circRNAs in NSCLC still needs to be studied. We selected a differentially expressed hsa_circ_0006677 (circ_0006677) in NSCLC through analyzing the GSE158695 and GSE112214 datasets. Expression of circ_0006677 was evaluated by real-time quantitative polymerase-chain reaction (RT-qPCR). Effects of circ_0006677 overexpression on NSCLC cell proliferation, apoptosis, migration, invasion, and stemness were determined by clonogenic, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and sphere formation assays. The regulatory mechanism of circ_0006677 was predicted by bioinformatics analysis and verified by dual-luciferase reporter and RIP assays. Animal experiments were carried out to validate the function of circ_0006677 in vivo. We observed the downregulation of circ_0006677 in NSCLC samples and cells. Functionally, circ_0006677 overexpression decreased xenograft tumor growth and restrained NSCLC cell proliferation, invasion, migration, stemness, and induced NSCLC cell apoptosis in vitro. Molecular mechanism experiments exhibited that circ_0006677 functioned as a miR-1245a sponge and mediated SATB2 expression through adsorbing miR-1245a. Either miR-1245a overexpression or SATB2 knockdown weakened circ_0006677 overexpression-mediated repression on proliferation, invasion, migration, and stemness. In conclusion, circ_0006677 regulated SATB2-mediated tumor-suppressive effect via acting as a miR-1245a sponge in NSCLC, providing a new mechanism for understanding the progression of NSCLC.

Long non-coding RNA (lncRNA) CYTOR promotes hepatocellular carcinoma proliferation by targeting the microRNA-125a-5p/LASP1 axis.

This study investigated the function of long non-coding RNA (lncRNA) cytoskeleton regulator RNA (CYTOR) in hepatocellular carcinoma (HCC). In HCC, the expression of CYTOR and microRNA (miR)-125a-5p were measured by quantitative real-time PCR (qRT-PCR). The expression of actin skeletal protein 1 (LASP1) was evaluated by Western blot analysis. Flow cytometry assays, transwell assays, colony formation assay, and cell counting kit-8 (CCK-8) assay were used to evaluate the roles of miR-125a-5p and CYTOR in HCC cells. The target genes of CYTOR and miR-125a-5p were identified by bioinformatics analysis and Luciferase assay. CYTOR was upregulated in HCC cell lines, and knockdown of CYTOR inhibited HCC cell growth. MiR-125a-5p was downregulated in HCC cells and a target of CYTOR in regulating HCC progression. Furthermore, LASP1 was a downstream target of miR-125a-5p. Finally, CYTOR was found to be involved in HCC progression in vivo. CYTOR promotes HCC development by regulating the miR-125a-5p/LASP1 axis.

Knockdown of long non-coding RNA SNHG8 suppresses the progression of esophageal cancer by regulating miR-1270/BACH1 axis.

The emerging evidence showed that lncRNAs (long non-coding RNAs) could regulate the progression and affect the malignant behaviors of cancers. LncRNA SNHG8 (small nucleolar RNA host gene 8) has been reported to participate in most cancers development. Here in this study, the role of lncRNA SNHG8 in esophageal cancer was uncovered by a series of functional experiments. The expression pattern of SNHG8 in tumor tissues or cells was first detected by qRT-PCR. Using a lentivirus knockdown shRNA is to repress the expression of SNHG8. Subsequently, the in vitro and in vivo experiments were utilized to evaluate whether the malignant behaviors of esophageal cancer were influenced by knockdown SNHG8. The results indicated that lncRNA SNHG8 should be a cancer-promoting factor with a relatively high expression level in esophageal cancer. Moreover, knockdown SNHG8 inhibited the cell viability and induced cell apoptosis in KYSE30 and TE-1 cells. In addition, based on the results of the binding site analysis and the luciferase reporter system, SNHG8 functions by the miR-1270/BACH1 axis. The follow-up experiments verified that lncRNA SNHG8 could down-regulate the expression of miR-1270 to increase the BACH1 expression. Finally, we confirmed that knockdown SNHG8 retarded the progression of esophageal cancer with a xenograft model. To sum up, our findings suggested that lncRNA SNHG8 is a cancer-promoting factor in esophageal cancer. Knockdown SNHG8 could suppress the progression of esophageal cancer, which implies SNHG8 could be used as a therapeutic target in esophageal cancer.