Downregulation of miR-222-3p Reverses Doxorubicin-Resistance in LoVo Cells Through Upregulating Forkhead Box Protein P2 (FOXP2) Protein

Validation of Selected MicroRNA Transcriptome Data in the Bovine Corpus Luteum during Early Pregnancy by RT-qPCR

In cattle, the corpus luteum (CL) is pivotal in maintaining early pregnancy by secreting progesterone. To establish pregnancy, the conceptus produces interferon-τ, preventing luteolysis and initiating the transformation of the CL spurium into a CL verum. Although this transformation is tightly regulated, limited data are available on the expression of microRNAs (miRNAs) during and after this process. To address this gap, we re-analyzed previously published RNA-Seq data of CL from pregnant cows and regressed CL from non-pregnant cows. This analysis identified 44 differentially expressed miRNAs. From this pool, three miRNAs-bta-miR-222-3p, bta-miR-29c, and bta-miR-2411-3p-were randomly selected for relative quantification. Using bovine ovaries (n = 14) obtained from an abattoir, total RNA (including miRNAs) was extracted and converted to cDNA for RT-qPCR. The results revealed that bta-miR-222-3p was downregulated (p = 0.016) in pregnant females compared to non-pregnant cows with regressed CL. However, no differences in miRNA expression were observed between CL of pregnant and non-pregnant cows for bta-miR-29c (p > 0.32) or bta-miR-2411-3p (p > 0.60). In silico prediction approaches indicated that these miRNAs are involved in pathways regulating pregnancy maintenance, such as the VEGF- and FoxO-signaling pathways. Additionally, their biogenesis is regulated by GABPA and E2F4 transcription factors. The validation of selected miRNA expression in the CL during pregnancy by RT-qPCR provides novel insights that could potentially lead to the identification of biomarkers related to CL physiology and pregnancy outcome.

Promoter of lncRNA MORT is aberrantly methylated in colorectal cancer

Aberrant DNA methylation plays essential roles in the colorectal cancer (CRC) carcinogenesis and has been demonstrated as a promising marker for cancer early detection. In this project, methylation status of the MORT promoter was studied in CRC and their marginal tissues using qMSP assay. Furthermore, we investigated the molecular function of MORT in CRC progression using computational analysis. The results showed a high methylation level of MORT promoter in CRC tissues. By in silico analysis, we found that MORT downregulation could promote the proliferation of CRC cells via sponging of has-miR-574-5p and has-miR-31-5p, and alteration of their targets expression pattern such as MYOCD and FOXP2. In conclusion, based on our results, promoter hypermethylation of MORT might be considered as a potential biomarker for CRC detection.

Utilizing non-coding RNA-mediated regulation of ATP binding cassette (ABC) transporters to overcome multidrug resistance to cancer chemotherapy

Multidrug resistance (MDR) is one of the primary factors that produces treatment failure in patients receiving cancer chemotherapy. MDR is a complex multifactorial phenomenon, characterized by a decrease or abrogation of the efficacy of a wide spectrum of anticancer drugs that are structurally and mechanistically distinct. The overexpression of the ATP-binding cassette (ABC) transporters, notably ABCG2 and ABCB1, are one of the primary mediators of MDR in cancer cells, which promotes the efflux of certain chemotherapeutic drugs from cancer cells, thereby decreasing or abolishing their therapeutic efficacy. A number of studies have suggested that non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a pivotal role in mediating the upregulation of ABC transporters in certain MDR cancer cells. This review will provide updated information about the induction of ABC transporters due to the aberrant regulation of ncRNAs in cancer cells. We will also discuss the measurement and biological profile of circulating ncRNAs in various body fluids as potential biomarkers for predicting the response of cancer patients to chemotherapy. Sequence variations, such as alternative polyadenylation of mRNA and single nucleotide polymorphism (SNPs) at miRNA target sites, which may indicate the interaction of miRNA-mediated gene regulation with genetic variations to modulate the MDR phenotype, will be reviewed. Finally, we will highlight novel strategies that could be used to modulate ncRNAs and circumvent ABC transporter-mediated MDR.

miRNAs as short non-coding RNAs in regulating doxorubicin resistance

The treatment of cancer patients has been prohibited by chemoresistance. Doxorubicin (DOX) is an anti-tumor compound disrupting proliferation and triggering cell cycle arrest via inhibiting activity of topoisomerase I and II. miRNAs are endogenous RNAs localized in cytoplasm to reduce gene level. Abnormal expression of miRNAs changes DOX cytotoxicity. Overexpression of tumor-promoting miRNAs induces DOX resistance, while tumor-suppressor miRNAs inhibit DOX resistance. The miRNA-mediated regulation of cell death and hallmarks of cancer can affect response to DOX chemotherapy in tumor cells. The transporters such as P-glycoprotein are regulated by miRNAs in DOX chemotherapy. Upstream mediators including lncRNAs and circRNAs target miRNAs in affecting capacity of DOX. The response to DOX chemotherapy can be facilitated after administration of agents that are mostly phytochemicals including curcumol, honokiol and ursolic acid. These agents can regulate miRNA expression increasing DOX's cytotoxicity. Since delivery of DOX alone or in combination with other drugs and genes can cause synergistic impact, the nanoparticles have been introduced for drug sensitivity. The non-coding RNAs determine the response of tumor cells to doxorubicin chemotherapy. microRNAs play a key role in this case and they can be sponged by lncRNAs and circRNAs, showing interaction among non-coding RNAs in the regulation of doxorubicin sensitivity.

Role of forkhead box proteins in regulation of doxorubicin and paclitaxel responses in tumor cells: A comprehensive review

Chemotherapy is one of the common first-line therapeutic methods in cancer patients. Despite the significant effects in improving the quality of life and survival of patients, chemo resistance is observed in a significant part of cancer patients, which leads to tumor recurrence and metastasis. Doxorubicin (DOX) and paclitaxel (PTX) are used as the first-line drugs in a wide range of tumors; however, DOX/PTX resistance limits their use in cancer patients. Considering the DOX/PTX side effects in normal tissues, identification of DOX/PTX resistant cancer patients is required to choose the most efficient therapeutic strategy for these patients. Investigating the molecular mechanisms involved in DOX/PTX response can help to improve the prognosis in cancer patients. Several cellular processes such as drug efflux, autophagy, and DNA repair are associated with chemo resistance that can be regulated by transcription factors as the main effectors in signaling pathways. Forkhead box (FOX) family of transcription factor has a key role in regulating cellular processes such as cell differentiation, migration, apoptosis, and proliferation. FOX deregulations have been associated with resistance to chemotherapy in different cancers. Therefore, we discussed the role of FOX protein family in DOX/PTX response. It has been reported that FOX proteins are mainly involved in DOX/PTX response by regulation of drug efflux, autophagy, structural proteins, and signaling pathways such as PI3K/AKT, NF-kb, and JNK. This review is an effective step in introducing the FOX protein family as the reliable prognostic markers and therapeutic targets in cancer patients.

Two Enhances the Cisplatin Sensitivity of Cervical Cancer Cells via Suppression of c-MET Expression

Background

The drug resistance of chemotherapeutic agents leads to unsatisfactory survival rates for cervical cancer (CC) patients. We aimed to explore the effect of FOXP2 on the sensitivity of CC cells to cisplatin (DDP) and its mechanism in Changde, China in 2018.

Methods

A Total of 6 cervical cancer tissue samples including 3 patients with cisplatin sensitivity and 3 patients with cisplatin resistance, who received DDP-based treatment, were obtained from Changde First People's Hospital, Changde City during 2021, and FOXP2 level was detected by Western blot. The expression levels of FOXP2 and c-MET (hepatocyte growth factor receptor, c-MET) in cells were determined by q-PCR and Western blot analysis. The cell survival, apoptosis, and clone formation were analyzed by flow cytometry, MTT assay, or clone formation assay. Dual-luciferase reporter assays and Chromatin immunoprecipitation were applied to verify the regulation between FOXP2 and c-MET.

Results

FOXP2 was downregulated in cisplatin-resistant cervical cancer tissues and cells compared with control. FOXP2 overexpression in SiHa/DDP cells inhibited cell proliferation and promoted cell apoptosis, whereas down-regulation of FOXP2 in SiHa cells had the opposite result. FOXP2 enhanced chemosensitive to DDP in CC cells. FOXP2 is negatively correlated with c-MET expression level in SiHa and SiHa/DDP cells. Mechanistically, FOXP2 binds to the promoter region of c-MET to regulate its expression in CC cells negatively. Overexpression of c-MET can attenuate the enhancement of DDP-induced apoptosis caused by FOXP2 overexpression.

Conclusion

This is a novel study on the role of FOXP2 in promoting the DDP sensitivity of CC cells by inhibiting c-MET. The FOXP2/c-MET signaling axis uncovered in the present study may be a novel therapeutic target for the DDP therapy resistance of CC.

MiR-222-3p Aggravates the Inflammatory Response by Targeting SOCS1 to Activate STAT3 Signaling in Ulcerative Colitis

BACKGROUND

Ulcerative colitis is characterized by relapsing inflammation in the gastrointestinal tract with limited treatment options. The aim of the present study was to assess the anti-inflammatory effect of Suppressor of cytokine signaling (SOCS1) on lipopolysac- charide-stimulated RAW264.7 cells and to investigate its potential mechanisms.

METHODS

The in vitro ulcerative colitis model was established by using lipopolysaccharide-stimulated RAW264.7 cells. Western blot- ting was used to detect the protein expression levels of SOCS1, JAK2, STAT3, and VDR. Reverse transcription-quantitative polymerase chain reaction was used to measure the mRNA expression of SOCS1, miR-222-3p, and VDR. An enzyme-linked immunosorbent assay was performed to measure the levels of inflammatory cytokines. A luciferase assay assessed the binding of SOCS1 to miR-222-3p. A total of 15 patients with ulcerative colitis and 18 healthy controls were recruited. The expression levels of SOCS1 and miR-222-3p in the colonic mucosa tissues of patients with ulcerative colitis and healthy controls were determined by reverse transcription-quantitative polymerase chain reaction.

RESULTS

SOCS1 upregulation inhibited the lipopolysaccharide-induced inflammation in RAW264.7 cells. SOCS1 was confirmed to be tar- geted by miR-222-3p. Silencing SOCS1 significantly abolished the inhibitory effects of miR-222-3p downregulation on inflammation. MiR-222-3p activated STAT3 signaling and reduced VDR expression by targeting SOCS1 in lipopolysaccharide-treated RAW264.7 cells. Additionally, miR-222-3p expression was upregulated in ulcerative colitis patients (P = 5.16E-10), while SOCS1 (P = 2.75E-10) and VDR (P = 52.5E-9) expression was downregulated in ulcerative colitis patients. Endoscopic scores (UCEIS) revealed significant positive cor- relation with miR-222-3p and negative correlation with SOCS1 and VDR.

CONCLUSION

MiR-222-3p targets SOCS1 to aggravate the inflammatory response by suppressing VDR and activating STAT3 signaling in ulcerative colitis.

The role of human umbilical cord mesenchymal stem cells-derived exosomal microRNA-431-5p in survival and prognosis of colorectal cancer patients

We aim to discuss the role of miR-431-5p in colorectal cancer (CRC) progression via regulating peroxiredoxin 1 (PRDX1). miR-431-5p and PRDX1 expression were detected in CRC tissues and cells, and the relationship between miR-431-5p expression and prognosis of CRC patients was analyzed. Exosomes were extracted from human umbilical cord mesenchymal stem cells (hUCMSCs) and co-cultured with LoVo cells. MTT assay, flow cytometry and Transwell assay were implemented to test cell viability, apoptosis and invasion and migration ability, respectively. The tumor growth was determined as well, and the binding relation between miR-431-5p and PRDX1 was confirmed. miR-431-5p was downregulated and PRDX1 was upregulated in CRC, and miR-431-5p downregulation was associated with poor prognosis. hUCMSC-Exos suppressed the malignant behaviors of LoVo cells, and overexpression of miR-431-5p further aggravated the inhibitory effect of hUCMSC-Exos on LoVo cells. hUCMSC-Exos inhibited PRDX1 expression via miR-431-5p. PRDX1 was targeted by miR-431-5p. miR-431-5p serves as a prognostic biomarker in CRC, and hUCMSC-Exos transfer of miR-431-5p decelerates CRC cell growth by inhibiting PRDX1.

Exosomal transfer of circ_0006174 contributes to the chemoresistance of doxorubicin in colorectal cancer by depending on the miR-1205/CCND2 axis

Exosomes are the mediators of intercellular signal transduction, and they have been involved in the carcinogenesis and chemoresistance of tumor cells. Herein, we intended to investigate whether circular RNA (circRNA) circ_0006174 can regulate chemoresistance of doxorubicin (DOX) in colorectal cancer via exosomes. Forty-one pairs of normal and CRC (DOX sensitive, n = 16; DOX resistant, n = 25) samples were collected. The resistant cell lines (LoVo/DOX and HCT116/DOX) were constructed by exposure of parental cell lines (LoVo and HCT116) to DOX. The detection of circ_0006174, microRNA-1205 (miR-1205), and cyclin D2 (CCND2) was performed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8(CCK-8) was applied for determining the half of inhibitory concentration (IC50) of DOX and cell proliferation. The migration and invasion capacities were analyzed via transwell assay. Exosomes were extracted using ultracentrifugation. Protein levels were determined using western blot. Dual-luciferase reporter assay was used for affirming target interaction. In vivo experiment was performed by establishing xenograft models in mice. Circ_0006174 level was upregulated in DOX-resistant CRC tissues and cells. The downregulation of circ_0006174 inhibited DOX resistance, cell proliferation, migration, and invasion in DOX-resistant CRC cells. Interestingly, the abundant circ_0006174 was enriched in exosomes derived from DOX-resistant CRC cells. Furthermore, circ_0006174 could enhance DOX resistance via the exosomal intercellular transfer. Moreover, we validated the target relation of circ_0006174/miR-1205 or miR-1205/CCND2. The effect of exosomal circ_0006174 on DOX resistance was achieved by upregulating the miR-1205-mediated CCND2. In vivo, knockdown of circ_0006174 also enhanced tumor sensitivity to DOX by targeting miR-1205/CCND2 axis. Altogether, these findings unraveled that circ_0006174-enriched exosomes elevated DOX chemoresistance in CRC by the miR-1205/CCND2 axis. The exosomal circ_0006174 can be used as an available biomarker for the diagnosis of chemoresistance in CRC.

Advances in understanding the role of P-gp in doxorubicin resistance: Molecular pathways, therapeutic strategies, and prospects

P-glycoprotein (P-gp) is a drug efflux transporter that triggers doxorubicin (DOX) resistance. In this review, we highlight the molecular avenues regulating P-gp, such as Nrf2, HIF-1α, miRNAs, and long noncoding (lnc)RNAs, to reveal their participation in DOX resistance. These antitumor compounds and genetic tools synergistically reduce P-gp expression. Furthermore, ATP depletion impairs P-gp activity to enhance the antitumor activity of DOX. Nanoarchitectures, including liposomes, micelles, polymeric nanoparticles (NPs), and solid lipid nanocarriers, have been developed for the co-delivery of DOX with anticancer compounds and genes enhancing DOX cytotoxicity. Surface modification of nanocarriers, for instance with hyaluronic acid (HA), can promote selectivity toward cancer cells. We discuss these aspects with a focus on P-gp expression and activity.

The related miRNAs involved in doxorubicin resistance or sensitivity of various cancers: an update

Doxorubicin (DOX) is an effective chemotherapy agent against a wide variety of tumors. However, intrinsic or acquired resistance diminishes the sensitivity of cancer cells to DOX, which leads to a cancer relapse and treatment failure. Resolutions to this challenge includes identification of the molecular pathways underlying DOX sensitivity/resistance and the development of innovative techniques to boost DOX sensitivity. DOX is classified as a Topoisomerase II poison, which is cytotoxic to rapidly dividing tumor cells. Molecular mechanisms responsible for DOX resistance include effective DNA repair and resumption of cell proliferation, deregulated development of cancer stem cell and epithelial to mesenchymal transition, and modulation of programmed cell death. MicroRNAs (miRNAs) have been shown to potentiate the reversal of DOX resistance as they have gene-specific regulatory functions in DOX-responsive molecular pathways. Identifying the dysregulation patterns of miRNAs for specific tumors following treatment with DOX facilitates the development of novel combination therapies, such as nanoparticles harboring miRNA or miRNA inhibitors to eventually prevent DOX-induced chemoresistance. In this article, we summarize recent findings on the role of miRNAs underlying DOX sensitivity/resistance molecular pathways. Also, we provide latest strategies for utilizing deregulated miRNA patterns as biomarkers or miRNAs as tools to overcome chemoresistance and enhance patient's response to DOX treatment.

MiR-222-3p induced by hepatitis B virus promotes the proliferation and inhibits apoptosis in hepatocellular carcinoma by upregulating THBS1

This study aimed to explore the role of miR-222-3p in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). MiR-222-3p expression in tumor tissues of HBV (+) or HBV (-) HCC patients and corresponding cell lines was detected by quantitative reverse transcription PCR (qRT-PCR). Cell proliferation was assessed by cell counting kit-8 (CCK-8) and colony formation assays. Cell apoptosis was evaluated by flow cytometry. The potential targets of miR-222-3p were predicted by Targetscan, and the binding relationship between miR-222-3p and thrombospondin-1 (THBS1) was determined by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. MiR-222-3p was significantly upregulated in HCC tissues and cell lines and further elevated by HBV infection. MiR-222-3p downregulation effectively inhibited the proliferation and induced the apoptosis of HBV (-) HepG2 cells, HBV (+) HepG2.2.15 cells, Huh7-V cells, and Huh7-HBV cells. In addition, miR-222-3p overexpression enhanced the proliferation of these cell lines but exhibited no obvious effect on their apoptosis. Mechanistically, miR-222-3p was directly bound to the 3'-UTR of THBS1 and acted as its competing endogenous RNA (ceRNA). Interestingly, THBS1 silencing attenuated the inhibitory effect of miR-222-3p downregulation on the proliferation of these cell lines in vitro. Our results revealed that HBV infection further increased miR-222-3p expression and promoted HCC progression via miR-222-3p-mediated THBS1 downregulation. Our findings suggest that miR-222-3p might be a potential diagnostic and therapeutic target for HCC and HBV-related HCC.

Emerging roles and mechanisms of microRNA‑222‑3p in human cancer (Review)

MicroRNAs (miRNAs/miRs) are a class of small non‑coding RNAs that maintain the precise balance of various physiological processes through regulating the function of target mRNAs. Dysregulation of miRNAs is closely associated with various types of human cancer. miR‑222‑3p is considered a canonical factor affecting the expression and signal transduction of multiple genes involved in tumor occurrence and progression. miR‑222‑3p in human biofluids, such as urine and plasma, may be a potential biomarker for the early diagnosis of tumors. In addition, miR‑222‑3p acts as a prognostic factor for the survival of patients with cancer. The present review first summarizes and discusses the role of miR‑222‑3p as a biomarker for diverse types of cancers, and then focuses on its essential roles in tumorigenesis, progression, metastasis and chemoresistance. Finally, the current understanding of the regulatory mechanisms of miR‑222‑3p at the molecular level are summarized. Overall, the current evidence highlights the crucial role of miR‑222‑3p in cancer diagnosis, prognosis and treatment.

The role of miRNAs and lncRNAs in conferring resistance to doxorubicin

Doxorubicin is a chemotherapeutic agent that inhibits topoisomerase II, intercalates within DNA base pairs and results in oxidative DNA damage, thus inducing cell apoptosis. Although it is effective in the treatment of a wide range of human cancers, the emergence of resistance to this drug can increase tumour growth and impact patients' survival. Numerous molecular mechanisms and signalling pathways have been identified that induce resistance to doxorubicin via stimulation of cell proliferation, cell cycle switch and preclusion of apoptosis. A number of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have also been identified that alter sensitivity to doxorubicin. Understanding the particular impact of these non-coding RNAs in conferring resistance to doxorubicin has considerable potential to improve selection of chemotherapeutic regimens for cancer patients. Moreover, modulation of expression of these transcripts is a putative strategy for combating resistance. In the current paper, the influence of miRNAs and lncRNAs in the modification of resistance to doxorubicin is discussed.

The role of non-coding RNAs in ABC transporters regulation and their clinical implications of multidrug resistance in cancer

INTRODUCTION

Multi-drug resistance (MDR) is a hindrance toward the successful treatment of cancers. The primary mechanism that gives rise to acquired chemoresistance is the overexpression of adenosine triphosphate-binding cassette (ABC) transporters. The dysregulation of non-coding RNAs (ncRNAs) is a widely concerned reason contributing to this phenotype.

AREAS COVERED

In this review, we describe the role of intracellular and exosomal ncRNAs including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) in ABC transporters-induced tumor MDR. Meanwhile, we will introduce the potential therapeutic strategies which reverse MDR in terms of reducing the expression of ABC transporters via targeting ncRNAs, like nucleic acid delivery with nanoparticles as well as miRNAs-targeted small molecular compounds.

EXPERT OPINION

The dysregulated ncRNAs-mediated overexpression of ABC transporters in chemo-resistant cancer is not negligible. Finding out the underlying mechanism may provide a theoretical basis for clinical therapy of cancer MDR, and the emergence of new approaches for gene therapy targeting ncRNAs to suppress ABC transporters makes reversing cancer MDR possible despite its clinical application requires further investigations. Also, the discovered ncRNAs regulating ABC transporters in chemo-resistant cancers are just a tip of the iceberg of the genetic transcripts, especially for circRNAs, which justify more concern.Abbreviations: MDR, multi-drug resistance; ABC, adenosine triphosphate-binding cassette; NcRNAs, non-coding RNAs; MiRNAs, microRNAs; LncRNAs, long non-coding RNAs; CircRNAs, circular RNAs; CeRNAs, competing endogenous RNAs; 3'UTR, 3'-untranslated regions; SLC, solute carrier; ABCB1/MDR1, ABC subfamily B member 1; ABCG2/BCRP, ABC subfamily G member 2; ABCCs/MRPs, ABC subfamily C 1 to 12; DLL1: Delta-like protein 1; DTX, docetaxel; DOX/ADM/ADR, doxorubicin/adriamycin; PTX, paclitaxel; VBL, vinblastine; VCR, vincristine; MTX, methotrexate; CDDP/DDP, cisplatin/cis-diaminedichloroplatinum; OXA/L-OHP, oxaliplatin; TMZ, temozolomide; 5-FU, 5-fluorouracil; MTA, pemetrexed; NSCLC, non-small cell lung carcinoma; HCC, hepatocellular carcinoma; CRC, colorectal carcinoma; RB, retinoblastoma; RCC, renal cell carcinoma; OS, osteosarcoma; PDAC, pancreatic ductal adenocarcinoma; TNBC, triple-negative breast cancer.

microRNA-222-Mediated VHL Downregulation Facilitates Retinoblastoma Chemoresistance by Increasing HIF1α Expression

Purpose

Retinoblastoma (RB) is the most common primary intraocular tumor in children. Chemoresistance is the major obstacle for treatment of these tumors. This study aims to determine whether or not downregulating microRNA-222 (miR-222) could serve as a potential therapeutic target for preventing chemoresistance in RB treatment.

Methods

Differentially expressed miR-222 in RB samples and its downstream target genes were predicted using bioinformatics methods. The expression of miR-222 was altered by mimic or inhibitor to examine its role in RB cell in response to the chemotherapeutic agent vincristine (VCR). Further bioinformatic analysis predicted involvement of the stability of hypoxia-inducible factor 1α (HIF1α) protein in regulation of the von Hippel–Lindau (VHL) tumor suppressor, followed by characterization of the effect of VHL on the ubiquitin–proteasome degradation of HIF1α. Next, VHL or HIF1α was overexpressed to determine their effects on RB cell activities after VCR treatment. In vivo assays were performed on nude mice to further verify the in vitro results.

Results

miR-222 is highly expressed in RB tissues and cells and was found to facilitate resistance of RB cells to VCR. Of note, miR-222 specifically bound to and negatively regulated VHL. VHL could inhibit the stability of HIF1α and promote the degradation of ubiquitin–proteasome, thus reducing HIF1α expression to attenuate VCR resistance in RB cells. Moreover, inhibition of miR-222 in combination with VCR suppressed tumor formation in nude mice.

Conclusions

miR-222 promotes the expression of HIF1α by targeting VHL, thus accelerating the resistance of RB cells to the chemotherapeutic agent VCR.

lncRNA-miRNA-mRNA interaction network for colorectal cancer; An in silico analysis

BACKGROUND

Colorectal cancer (CRC) is one of the most frequent and diagnosed diseases. Accumulating evidences showed that mRNAs and noncoding RNAs play important regulatory roles in tumorigenesis. Identification and determining the relationship between them can help diagnosis and treatment of cancer.

METHODS

Here we analyzed three microarray datasets; GSE110715, GSE32323 and GSE21510, to identify differentially expressed lncRNAs and mRNAs in CRC. The adjusted p-value ≤0.05 was considered statistically significant. Gene set enrichment analysis was carried out using DAVID tool. The miRCancer database was searched to obtain differentially expressed miRNAs in colorectal cancer, and the miRDB database was used to attain the targets of the obtained miRNAs. To predict the lncRNA-miRNA interactions we used DIANA-LncBase v2 and RegRNA 2.0. Finally the lncRNA-miRNA-mRNA-signaling pathway network was constructed using Cytoscape v3.1.

RESULTS

By analyzing the three datasets, a total of 21 mRNAs (15 up- and 6 down-regulated) and 24 lncRNAs (18 up- and 6 down-regulated) were identified as common differentially expressed genes between CRC tumor and marginal tissues. Nevertheless, the constructed lncRNA-miRNA-mRNA-signaling pathway network revealed a convergence on 6 lncRNAs (3 up- and 3 downregulated), 7 mRNAs (2 up- and 5 downregulated) and 6 miRNAs (3 up- and 3 downregulated). We found that dysregulation of lncRNAs such as PCBP1-AS1, UCA1 and SNHG16 could sequester several miRNAs such as hsa-miR-582-5p and hsa-miR-198 and promote the proliferation, invasion and drug resistance of colorectal cancer cells.

CONCLUSIONS

We introduced a set of lncRNAs, mRNAs and miRNAs differentially expressed in CRC which might be considered for further experimental research as potential biomarkers of CRC development.

Inhibition of TRIM32 Induced by miR-519d Increases the Sensitivity of Colorectal Cancer Cells to Cisplatin

BACKGROUND

Colorectal cancer is a leading cause of cancer-related death in the world. Despite cisplatin is a commonly used chemotherapeutic drug for the colorectal cancer treatment, resistance of cancer cells to cisplatin restricts its clinical efficacy. It is important to explore the potential mechanisms and take strategies to sensitize colorectal cancer cells to cisplatin treatment.

METHODS

Differences of TRIM32 and miR-519d expression between colorectal cancer cells and human normal colon epithelial cells were evaluated by qRT-PCR and Western blot assays. Cytotoxicity of cisplatin against colorectal cancer cells was tested by CCK-8 assay. Generation of reactive oxygen species (ROS), mitochondrial membrane potential and apoptosis was measured by flow cytometry. Dual-luciferase reporter assay was used to validate the association between miR-519d and TRIM32.

RESULTS

Significant increase of TRIM32 expression in colorectal cancer tissues and cell lines was observed. TRIM32 negatively regulated the cisplatin sensitivity in colorectal cancer cells. Mechanically, overexpression of TRIM32 was induced by decrease of miR-519d. Exogenous miR-519d can inhibit the expression of TRIM32 and thus promoted the cisplatin-induced apoptosis through the mitochondrial pathway.

CONCLUSION

Overexpression of TRIM32 was induced by the absence of miR-519d in colorectal cancer. MiR-519d can be used as a sensitizer during the cisplatin-based chemotherapy of colorectal cancer.