scholarly journals MiR-323a-3p Inhibits Tumor Growth and Gefitinib Resistance Acquisition by Targeting EGFR/ErbB3 in Colorectal Cancer

2021 ◽  
Author(s):  
Yuanzhou Zhang ◽  
Shunshun Liang ◽  
Bowen Xiao ◽  
Jingying Hu ◽  
Yechun Pang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Growth ◽  
Tumor Growth ◽  
Western Blot ◽  
Cell Lines ◽  
Acquired Resistance ◽  
Luciferase Reporter ◽  
Apoptosis Pathway ◽  
Acquired Drug Resistance ◽  
Protein Levels

Abstract Background: EGFR-TKIs are prone to develop acquired drug resistance in colorectal cancer and are only applicable in Kras wild type colorectal cancer patients. This study aimed to determine the reasons for the poor treatment efficacy of TKIs in Kras mutant CRC and to improve the treatment effect. Method: The RTK Phosphorylation Membrane array was used to detect and screen changes in phosphorylated protein levels in KRAS mutant-resistant CRC cells. qRT-PCR, western blot and TCGA database were applied for reporting the expression of ERGR and ErbB3 in CRC. Luciferase reporter and western blot examined the network of miR-323a-3p. RTCA, colony formation, CCK-8, caspase-3/7 activity and Flow cytometry probed the impacts of miR-323a-3p on CRC cell growth.Results: We illustrated that ErbB3 and EGFR were activated in gefitinib-resistant Kras mutant colorectal cancer cell lines. ErbB3 is highly expressed in Kras mutant patient tissues, and patients with ErbB3high/EGFRhigh had a poorer prognosis. Mechanically, We found and verified that the tumor suppressor miR-323a-3p simultaneously directly targeted EGFR/ErbB3 and inhibited tumor cell growth by activating the apoptosis pathway. Further functionality studies identified miR-323a-3p synergized with gefitinib to inhibit tumor growth, and this synergy prevented the development of acquired resistance to gefitinib in CRC cell lines.Conclusion: Accordingly, these data indicate that Kras mutant CRC TKI resistance occurs due to the activation of EGFR and ErbB3. Thus, miR-323a-3p has the potential to treat Kras-mutated colorectal cancer by targeting ErbB3/EGFR.

scholarly journals Circular RNA circCSPP1 knockdown attenuates doxorubicin resistance and suppresses tumor progression of colorectal cancer via miR-944/FZD7 axis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lanlan Xi ◽  
Quanlin Liu ◽  
Wei Zhang ◽  
Linshan Luo ◽  
Jingfeng Song ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Tumor Growth ◽  
Circular Rna ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Protein Levels ◽  
Cell Progression ◽  
Rna Immunoprecipitation ◽  
Induced Apoptosis

Abstract Background Circular RNAs (circRNAs) have been reported to play vital roles in colorectal cancer (CRC). However, only a few circRNAs have been experimentally validated and functionally described. In this research, we aimed to reveal the functional mechanism of circCSPP1 in CRC. Methods 36 DOX sensitive and 36 resistant CRC cases participated in this study. The expression of circCSPP1, miR-944 and FZD7 were detected by quantitative real time polymerase chain reaction (qRT-PCR) and the protein levels of FZD7, MRP1, P-gp and LRP were detected by western blot. Cell proliferation, migration, invasion, and apoptosis were assessed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay, transwell assay, or flow cytometry analysis, respectively. The interaction between miR-944 and circCSPP1 or frizzled-7 (FZD7) was predicted by Starbase 3.0 and verified by the dual luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull down assay. Xenograft tumor assay was performed to examine the effect of circCSPP1 on tumor growth in vivo. Results The expression of circCSPP1 and FZD7 was upregulated while miR-944 expression was downregulated in doxorubicin (DOX)-resistant CRC tissues and cells. CircCSPP1 knockdown significantly downregulated enhanced doxorubicin sensitivity, suppressed proliferation, migration, invasion, and induced apoptosis in DOX-resistant CRC cells. Interestingly, we found that circCSPP1 directly downregulated miR-944 expression and miR-944 decreased FZD7 level through targeting to 3′ untranslated region (UTR) of FZD7. Furthermore, circCSPP1 mediated DOX-resistant CRC cell progression and doxorubicin sensitivity by regulating miR-944/FZD7 axis. Besides, circCSPP1 downregulation dramatically repressed CRC tumor growth in vivo. Conclusion Our data indicated that circCSPP1 knockdown inhibited DOX-resistant CRC cell growth and enhanced doxorubicin sensitivity by miR-944/FZD7 axis, providing a potential target for CRC therapy.

scholarly journals Knockdown of Long Non-Coding RNA XIST Inhibited Doxorubicin Resistance in Colorectal Cancer by Upregulation of miR-124 and Downregulation of SGK1

2018 ◽  
Vol 51 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Jia Zhu ◽  
Rui Zhang ◽  
Dongxiang Yang ◽  
Jibin Li ◽  
Xiaofei Yan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Western Blot ◽  
Molecular Mechanisms ◽  
Luciferase Reporter ◽  
Regulatory Function ◽  
Glutathione S Transferase ◽  
Protein Levels ◽  
Qrt Pcr ◽  
Ic50 Value

Background/Aims: Doxorubicin (DOX) is a widely used chemotherapeutic agent for colorectal cancer (CRC). However, the acquirement of DOX resistance limits its clinical application for cancer therapy. Mounting evidence has suggested that aberrantly expressed lncRNAs contribute to drug resistance of various tumors. Our study aimed to explore the role and molecular mechanisms of lncRNA X-inactive specific transcript (XIST) in chemoresistance of CRC to DOX. Methods: The expressions of XIST, miR-124, serum and glucocorticoid-inducible kinase 1 (SGK1) mRNA in DOX-resistant CRC tissues and cells were detected by qRT-PCR or western blot analysis. DOX sensitivity was assessed by detecting IC50 value of DOX, the protein levels of P-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) and apoptosis. The interactions between XIST, miR-124 and SGK1 were confirmed by luciferase reporter assay, qRT-PCR and western blot. Xenograft tumor assay was used to verify the role of XIST in DOX resistance in CRC in vivo. Results: XIST expression was upregulated and miR-124 expression was downregulated in DOX-resistant CRC tissues and cells. Knockdown of XIST inhibited DOX resistance of CRC cells, as evidenced by the reduced IC50 value of DOX, decreased P-gp and GST-π levels and enhanced apoptosis in XIST-silenced DOX-resistant CRC cells. Additionally, XIST positively regulated SGK1 expression by interacting with miR-124 in DOX-resistant CRC cells. miR-124 suppression strikingly reversed XIST-knockdown-mediated repression on DOX resistance in DOX-resistant CRC cells. Moreover, SGK1-depletion-elicited decrease of DOX resistance was greatly restored by XIST overexpression or miR-124 inhibition in DOX-resistant CRC cells. Furthermore, XIST knockdown enhanced the anti-tumor effect of DOX in CRC in vivo. Conclusion: XIST exerted regulatory function in resistance of DOX possibly through miR-124/SGK1 axis, shedding new light on developing promising therapeutic strategy to overcome chemoresistance in CRC patients.

scholarly journals miR-128 Targets the SIRT1/ROS/DR5 Pathway to Sensitize Colorectal Cancer to TRAIL-Induced Apoptosis

2018 ◽  
Vol 49 (6) ◽  
pp. 2151-2162 ◽  
Author(s):  
Bo Lian ◽  
Dongxiang Yang ◽  
Yanlong Liu ◽  
Gang Shi ◽  
Jibin Li ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Flow Cytometry ◽  
Western Blot ◽  
Cancer Cells ◽  
Cell Lines ◽  
Sirtuin 1 ◽  
Luciferase Reporter ◽  
Pcr Analysis ◽  
Reporter Assays ◽  
Induced Apoptosis

Background/Aims: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an ideal anti-tumor drug because it exhibits selective cytotoxicity against cancer cells. However, certain cancer cells are resistant to TRAIL, and the potential mechanisms are still unclear. The aim of this study was to reduce the resistance of colorectal cancer (CRC) cells to TRAIL. Methods: Quantitative real-time PCR analysis was performed to detect the expression of microRNA-128 (miR-128) in tissues from patients with CRC and CRC cell lines. MTT assays were used to evaluate the effect of miR-128 on TRAIL-induced cytotoxicity against CRC cell lines. The distribution of death receptor 5 (DR5) and the production of reactive oxygen species (ROS) were detected by flow cytometry analysis. Western blot, flow cytometry, and luciferase reporter assays were performed to evaluate the potential mechanism and pathway of miR-128-promoted apoptosis in TRAIL-treated CRC cells. Results: MiR-128 expression was downregulated in tumor tissues from patients with CRC as well as in CRC cell lines in vitro. The enforced expression of miR-128 sensitized CRC cells to TRAIL-induced cytotoxicity by inducing apoptosis. Mechanistically, bioinformatics, western blot analysis, and luciferase reporter assays showed that miR-128 directly targeted sirtuin 1 (SIRT1) in CRC cells. miR-128 overexpression suppressed SIRT1 expression, which promoted the production of ROS in TRAIL-treated CRC cells. This increase of ROS subsequently induced DR5 expression, and thus increased TRAIL-induced apoptosis in CRC cells. Conclusion: The combination of miR-128 with TRAIL may represent a novel approach for the treatment of CRC.

Apatinib inhibits tumor progression and promotes antitumor efficacy of cytotoxic drugs in esophageal squamous cell carcinoma.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e15554-e15554
Author(s):  
Yanyan Chi ◽  
Feng Wang ◽  
Xiangrui Meng ◽  
Zhengzheng Shan ◽  
Yan Sun ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Esophageal Cancer ◽  
Cell Growth ◽  
Western Blot ◽  
Cell Lines ◽  
Cytotoxic Drugs ◽  
Migration And Invasion ◽  
Protein Levels ◽  
Bax Protein

e15554 Background: Apatinib, a highly selective inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2), inhibits the angiogenesis of tumors. The function and mechanism of Apatinib in esophageal squamous cell carcinoma (ESCC) remains unknown. Methods: The expression of VEGFR-2 in ESCC cell lines (KYSE450, EC1, KYSE410, KYSE70) were detected by western blot. KYSE450 and EC1 cell lines were treated with Apatinib, or combined with cytotoxic drugs: paclitaxel (TAX), 5-fluorouracil (5-FU) or cisplatin (DDP) respectively. Cell proliferation was then measured using CCK-8 assay; cell apoptosis was analyzed by flow cytometry; cell migration and invasion were evaluated by wound healing and transwell assays. The expression of VEGFR-2, Bcl2, MMP-2/MMP-9, p-Akt and p-mTOR in KYSE450 and EC1 cell lines were determined by western blot. Esophageal cancer xenografts model was established and used to evaluate the antitumor effects of combination of Apatinib and cytotoxic drugs in vivo. Immunohistochemistry was used to detect the expression of Ki67, VEGFR-2 and CD31 in tumor tissues of esophageal cancer xenografts model. Results: We found that Apatinib efficiently inhibited cell growth, metastasis and activity of the Akt/mTOR pathway in ESCC cells. Western blot analysis showed that Apatinib significantly increased Bax protein levels, decreased VEGFR-2, Bcl2, MMP-2/MMP-9, p-Akt and p-mTOR protein levels in ESCC cells. Moreover, Apatinib enhanced chemosensitivity of cytotoxic drugs TAX, 5-FU and DDP by upregulating expression of Bax protein, and downregulating expression of VEGFR-2, Bcl2, MMP-2/MMP-9 protein in vitro. Compared with single agent groups, the combination of Apatinib with each chemotherapeutic drug significantly repressed tumor growth and angiogenesis through blocking the expression of Ki67, VEGFR-2 and CD31 in vivo. Conclusions: Taken together, Apatinib suppressed cell growth, migration and invasion, and promoted antitumor effect of chemotherapeutic agents in ESCC.

scholarly journals Hsa_circRNA_000166 facilitated cell growth and limited apoptosis through targeting miR-326 / LASP1 axis in colorectal cancer

2020 ◽  
Author(s):  
Qin Hao ◽  
Zhongtao Zhang
Keyword(s):  
Colorectal Cancer ◽  
Cell Growth ◽  
Cell Lines ◽  
Direct Interaction ◽  
Luciferase Assay ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Western Blot Assay ◽  
Apoptosis Assay ◽  
Geo Database

Abstract Background: Circular RNAs(circRNAs) belong to non-coding RNAs and widely expressed in a variety of cell species, including cancers. However, the function and mechanism of circRNAs in colorectal cancer (CRC) has not been well investigated. Methods: Microarray data of CRC from Gene Expression Omnibus (GEO) database was used to obtain DEGs. QRT-PCR and western blot assay were performed to determine the mRNA and protein levels of multiple genes, respectively. Cell growth and apoptosis assay were conducted to measure CRC cell proliferation and apoptosis, respectively. Luciferase assay was utilized to confirm the direct interaction between hsa_circRNA_000166 and miR-326. Results: We downloaded and analyzed the circRNA expression profile of CRC from the GEO database and identified 181 differentially expressed circRNAs between 10 pairs of CRC and adjacent normal tissues. Interestingly, we observed that the expression of hsa_circRNA_000166 was the top increased among these circRNAs. Then, we confirmed an upregulation of hsa_circRNA_000166 in CRC tissues and cell lines and observed that higher expression of hsa_circRNA_000166 was associated with poor 5-year survival rate of patients with CRC. Cell growth and apoptosis assay revealed that hsa_circRNA_000166 regulated the cell growth and apoptosis in CRC cell lines. Furthermore, we identified that hsa_circRNA_000166 targeted miR-326/LASP1 pathway using bioinformatic analysis and luciferase reporter assay. Finally, overexpression of miR-326 could sufficiently rescued the aberrant cell growth and apoptosis in CRC cell lines. Conclusion: Taken together, our results indicated that downregulation of hsa_circRNA_000166 inhibited the cell growth and facilitated apoptosis during CRC development by sponging miR-326 / LASP1 pathway.

Role of metalloproteinase-7 in oxaliplatin acquired resistance in colorectal cancer cell lines

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 20042-20042 ◽  
Author(s):  
V. Almendro ◽  
J. Maurel ◽  
J. Augé ◽  
G. Laus ◽  
J. Domingo-Domenech ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Western Blot ◽  
Cell Line ◽  
Cell Lines ◽  
Acquired Resistance ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Fasl Expression ◽  
Ic50 Values

20042 Background: Mechanisms responsible for acquired resistance in colorectal cancer (CRC) tumors are not well understood. Anticancer drugs have been shown to enhance FASL expression by NF-kB induction. Additionally Metalloproteinase (MMP)-7 is over-expressed in CRC and has been shown to inhibit apoptosis by cleavage of FASL. We have previously shown in vivo that, sFASL increment was associated with acquired chemoresistance. Therefore we speculate that inhibition of MMP-7 or NF-kB can reverse chemoresistance in CRC cell lines. Methods: We generated an oxaliplatin-resistant cells (HT29R) from a p53 mutated (HT29) cell line. Both cell lines were cultured for 72h with different concentrations of oxaliplatin, BAY11–7085 (inhibitor of NF-kB activation), 0.01 mM of the MMP-7 inhibitor 1,10-Phenanthroline monohydrate (1,10-PM) and 100 ng/ml of DX2 monoclonal antibody. Different drug combinations were performed. Citotoxicity was determined by the MTS method, and cell cycle was analysed at 72h. Cell lines were characterized for MMP-7 expression (ELISA), NF-KB (Western-Blot), Fas expression (immunohistochemistry) and FasL expression (Western-Blot). Results: FAS was down-expressed in HT29R compared to HT29. The HT29R cells showed a IC50 for oxaliplatin 2-fold higher than normal cells. Treatment with 1,10-PM decrease MMP-7 levels (p < 0.005) compared with untreated cells. Additionally, inhibition of MMP-7, restore IC50 values after oxaliplatin treatment in HT29R without changes in NF-KB expression. This oxaliplatin-resistant cell line, presents also sensibility for BAY11–7085, without affecting MMP-7 levels. Finally the addition of oxaliplatin to the MMP-7 inhibitor, increase FAS-mediated apoptosis (induced by DX2 antibody), suggesting that FASL cleavage is responsable of sensitivity. Conclusions: Reversal of oxaliplatin chemo-resistance can be obtained either by MMP-7 or NF-kB inhibition. Both drugs induced sFASL decrement, by inhibiting cleavage or expression, respectively. No significant financial relationships to disclose.

scholarly journals hsa_circRNA_000166 Facilitated Cell Growth and Limited Apoptosis through Targeting miR-326/LASP1 Axis in Colorectal Cancer

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Qin Hao ◽  
Zhongtao Zhang
Keyword(s):  
Colorectal Cancer ◽  
Cell Growth ◽  
Cell Lines ◽  
Bioinformatics Analysis ◽  
Gene Expression Omnibus ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Normal Tissues ◽  
Apoptosis Assay ◽  
Geo Database

Circular RNAs (circRNAs) belong to noncoding RNAs and are widely expressed in a variety of cell species, including cancers. However, the function and mechanism of circRNAs in colorectal cancer (CRC) has not been well investigated. Here, we firstly downloaded and analyzed the circRNA expression profile of CRC from the Gene Expression Omnibus (GEO) database. And we identified 181 differentially expressed circRNAs between 10 pairs of CRC and adjacent normal tissues. Interestingly, we observed that the expression of hsa_circRNA_000166 was the top increased among these circRNAs. Then, we confirmed an upregulation of hsa_circRNA_000166 in CRC tissues and cell lines and observed that higher expression of hsa_circRNA_000166 was associated with poor 5-year survival rate of patients with CRC. Next, we investigated the function of hsa_circRNA_000166 during CRC progression by knocking down its expression. Cell growth and apoptosis assay revealed that hsa_circRNA_000166 regulated the cell growth and apoptosis in CRC cell lines. Furthermore, we identified that hsa_circRNA_000166 targeted the miR-326/LASP1 pathway using bioinformatics analysis and luciferase reporter assay. Finally, suppression of miR-326 or overexpression of LASP1 could sufficiently rescue the aberrant cell growth and apoptosis in CRC cell lines. Taken together, our results indicated that downregulation of hsa_circRNA_000166 inhibited the cell growth and facilitated apoptosis during CRC development by sponging the miR-326/LASP1 pathway.

microRNA-133b Regulates Cell Proliferation and Cell Cycle Progression via Targeting HuR in Colorectal Cancer

2022 ◽  
Vol 12 (2) ◽  
pp. 335-345
Author(s):  
Xiaoyan Zhang ◽  
Wei Zhu ◽  
Junjie Lu
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cell Viability ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Quantitative Polymerase Chain Reaction ◽  
Luciferase Reporter ◽  
Protein Levels ◽  
Ht 29

MicroRNAs (miRNAs/miRs) have been identified to serve a key role in the development of tumors. However, the role of miR-133b in colorectal cancer (CRC) remains largely unclear. This study will investigate the role and mechanism of miR-133b in CRC. Reverse transcription-quantitative polymerase chain reaction analysis was performed to detect the level of miR-133b in CRC cell lines. Bioinformatics software TargetScan predicted the potential target genes of miR-133b, and a dual luciferase reporter assay was used to confirm this. To investigate the role of miR-133b in CRC cells, miR-133b was upregulated or downregulated in CRC cell lines (SW620 and HT-29) by transfecting with a miR-133b mimic or inhibitor, respectively. Subsequently, cell viability was analyzed using MTT assay, whereas cell apoptosis and the cell cycle distribution were analyzed by flow cytometry. In addition, the associated protein levels were detected using western blot analysis. The results demonstrated that miR-133b was significantly downregulated in CRC cell lines when compared with the normal colonic epithelial NCM-460 cell line. Human antigen R (HuR; also termed ELAVL1) was demonstrated to be a direct target of miR-133b and was negatively regulated by miR-133b. HuR was also notably upregulated in the CRC cell lines when compared with the normal control. Transfection of SW620 and HT-29 cells with the miR-133b mimic significantly inhibited cell viability, and induced cell apoptosis and G1 phase arrest, while upregulation of HuR demonstrated the opposite effects. Furthermore, the present data demonstrated that the miR-133b mimic significantly enhanced the protein levels of p21 and p27, and downregulated cyclin D1 and cyclin A levels in SW620 and HT-29 cells; the opposite effects were observed following treatment with the miR-133b inhibitor. In conclusion, the data indicate that miR-133b suppressed CRC cell growth by targeting HuR.

scholarly journals Recovery of miR-139-5p in Ovarian Cancer Reverses Cisplatin Resistance by Targeting C-Jun

2018 ◽  
Vol 51 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Ying Jiang ◽  
Jing Jiang ◽  
Haiqing Jia ◽  
Zhiwei Qiao ◽  
Jingru Zhang
Keyword(s):  
Ovarian Cancer ◽  
Drug Resistance ◽  
Cell Lines ◽  
Cisplatin Resistance ◽  
Acquired Resistance ◽  
B Cell Lymphoma ◽  
Luciferase Reporter ◽  
Acquired Drug Resistance ◽  
Ovarian Cancer Cell Lines ◽  
Platinum Based Chemotherapy

Background/Aims: In platinum-based chemotherapy for ovarian cancer, acquired drug resistance is a frequent occurrence. Because recent studies have demonstrated that dysregulation of microRNAs (miRNAs) is partly responsible for the induction of acquired drug resistance in cancers, we hypothesized that correcting the dysregulation of key miRNAs would reverse the acquired resistance to platinum-based drugs in ovarian cancer. Methods: Cisplatin-resistant SKOV3 and A2780 ovarian cancer cell lines (SKOV3-R and A2780-R, respectively) were established by long-term exposure to cisplatin. MTT assays were performed to evaluate the viability of SKOV3, SKOV3-R, A2780, and A2780-R cells. Quantitative PCR was used to examine the expression of miR-139-5p in these cell lines. The regulatory mechanism was confirmed by western blot analysis and luciferase reporter assays. After treatment with miR-139-5p and cisplatin, mitochondrial membrane potential and apoptosis were measured by using flow cytometry. Interaction with c-Jun and activating transcription factor 2 (ATF2) was evaluated by co-immunoprecipitation. Expression of B-cell lymphoma-extra large (Bcl-xl) and activation of caspase-9 and caspase-3 were detected by western blotting. Results: Expression of miR-139-5p was decreased in SKOV3-R and A2780-R cells. Recovery of miR-139-5p increased the sensitivity of SKOV3-R and A2780-R cells to cisplatin treatment, inhibited the interaction of c-Jun and ATF2, and decreased Bcl-xl expression in SKOV3-R and A2780-R cells. Expression of miR-139-5p promoted cisplatin-induced mitochondrial apoptosis through binding the 3′ untranslated region of c-Jun mRNA. Conclusion: Recovery of miR-139-5p suppressed the expression of c-Jun and thus reversed cisplatin-resistance in ovarian cancer.

scholarly journals CircLRP6 contributes to prostate cancer growth and metastasis by binding to miR-330-5p to up-regulate NRBP1

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Linghui Qin ◽  
Xiaosong Sun ◽  
Fei Zhou ◽  
Cheng Liu
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Cell Growth ◽  
Tumor Growth ◽  
Western Blot ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Mesenchymal Transition

Abstract Background Circular RNA low-density lipoprotein receptor-related protein 6 (circLRP6) is considered as an oncogene in many types of cancers. However, the function and mechanisms of circLRP6 in prostate cancer (PCa) tumorigenesis remain largely undefined. Methods Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot assays were conducted to assess the expression of circLRP6, microRNA (miR)-330-5p, and nuclear receptor binding protein 1 (NRBP1). Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2’-deoxyuridine (EDU) incorporation, flow cytometry, transwell, wound healing, and western blot assays were performed to detect cell proliferation, apoptosis, and metastasis in vitro. Subcutaneous tumor growth was observed in nude mice to investigate the role of circLRP6 in vivo. The targeting relationship between miR-330-5p and NRBP1 or circLRP6 was verified using dual-luciferase reporter, pull-down, and RNA immunoprecipitation (RIP) assays. Immunohistochemistry was employed to test relative protein expression. Results CircLRP6 was highly expressed in PCa tissues and cells, knockdown of circLRP6 impaired PCa cell growth and metastasis in vitro by affecting cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT). Mechanistic studies showed that circLRP6 could competitively bind with miR-330-5p to prevent the degradation of its target gene NRBP1. Rescue assay suggested that miR-330-5p inhibition reversed the inhibitory effects of circLRP6 knockdown on PCa cell growth and metastasis. Moreover, overexpression of miR-330-5p suppressed PCa progression via NRBP1. Notably, tumor formation assay indicated that circLRP6 silencing impeded tumor growth and EMT in vivo. Conclusion Our findings demonstrated that circLRP6 promoted PCa tumorigenesis and metastasis through miR-330-5p/NRBP1 axis, suggesting a potential therapeutic target for PCa.

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