LINC00665 promotes glycolysis in lung adenocarcinoma cells via the let-7c-5p/HMMR axis.

Lung adenocarcinoma (LUAD) is one of the most lethal and common malignancies. The energy metabolism of LUAD is a critical factor affecting its malignant progression, and research on this topic can aid in the development of novel cancer treatment targets. Bioinformatics analysis of the expression of long non-coding RNA (lncRNA) LINC00665 in LUAD was performed. Downstream regulatory molecules of LINC00665 were predicted using the StarBase database. We used quantitative reverse transcription polymerase chain reaction and western blot to measure the expression at mRNA and protein levels, respectively. The effects of the LINC00665/let-7c-5p/HMMR axis on cell viability in vitro were tested by CCK-8 assay. The regulatory effects on glycolysis were analyzed by extracellular acidification rate, oxygen consumption rate, glucose uptake, adenosine triphosphate production, and lactate production. The predicted competitive endogenous RNA mechanism between LINC00665 and let-7c-5p/HMMR was verified by a dual-luciferase reporter gene assay. LINC00665 was upregulated in LUAD. Silencing LINC00665 inhibited tumor proliferation and reduced the glycolytic activity of tumor cells. Additionally, the expression of LINC00665 had a negative correlation with that of let-7c-5p, while the expression of HMMR was remarkably inhibited by let-7c-5p. HMMR could affect the development of LUAD by influencing glycolytic capacity. Mechanistically, LINC00665 acted as a molecular sponge to absorb let-7c-5p and targeted HMMR. Transfection of let-7c-5p inhibitor or overexpression of HMMR plasmid could reverse the inhibition in proliferation and glycolysis of LUAD cells induced by silencing of LINC00665. In summary, this study demonstrated that the LINC00665/let-7c-5p/HMMR regulatory axis promoted the tumorigenesis of LUAD by enhancing aerobic glycolysis, suggesting that this regulatory axis was an effective target for inhibiting LUAD progression and providing theoretical support for the development of new drugs for LUAD.

LINC00665 promotes the progression and immune evasion of lung cancer by facilitating the translation of TCF7 protein through dependence on IRES.

OBJECTIVE: To investigate the influence of LINC00665 on the development and immune evasion of lung cancer. METHODS: Tumor tissues and corresponding adjacent tissues were collected from 84 lung cancer patients, categorized into non-metastatic (n = 58) and metastatic (n = 26) groups. LINC00665 expression in lung cancer and metastatic lung cancer tissues was assessed via qRT-PCR. Pearson correlation analysis was conducted to examine the correlation between LINC00665 and immune-modulating cytokines (TGF-ß, IL-10, IL-1ß, IFN-γ, IL-2, TNF-α). A549 and H1299 cells, with relatively high LINC00665 expression, were used for in vitro studies. Cells were transfected with LINC00665-targeting shRNA, and changes in proliferation, apoptosis, migration, invasion, and NK cell cytotoxicity were assessed. Downstream molecular mechanisms of LINC00665 were investigated using GEO database analysis, highlighting the association with HHLA2. LINC00665's role in promoting HHLA2 expression via binding with TCF7 was explored. In low LINC00665-expressing A549/H1299 cells, overexpression of HHLA2 was performed to evaluate effects on malignant behavior and NK cell sensitivity. A xenograft model was established for in vivo validation through tumor volume and weight measurements, Ki-67 immunoreactivity analysis, and flow cytometry analysis of CD107a + NK cells. RESULTS: LINC00665, TCF7 mRNA, and HHLA2 mRNA expression levels were significantly higher in lung cancer tissues than adjacent tissues, with non-metastatic lung cancer showing higher expression than metastatic lung cancer. In metastatic lung cancer, LINC00665 positively correlated with immune-suppressive cytokines (TGF-ß, IL-10, IL-1ß) and negatively correlated with anti-tumor cytokines (IFN-γ, IL-2, TNF-α). LINC00665 knockdown significantly inhibited lung cancer cell growth and metastasis, promoting sensitivity to NK cells. Further analysis revealed that LINC00665 recruits transcription factor TCF7 to upregulate HHLA2 expression in lung cancer cells, thereby facilitating lung cancer development and immune escape. CONCLUSION: LINC00665, through recruitment of TCF7 and upregulation of HHLA2, inhibits NK cell cytotoxicity, promoting the development and immune evasion of lung cancer.

Blockage of MDM2-mediated p53 ubiquitination by yuanhuacine restrains the carcinogenesis of prostate carcinoma cells by suppressing LncRNA LINC00665.

Prostate cancer (PCa) is a challenging issue for men's health worldwide due to its uncontrolled proliferation and high metastatic potential. Increasing evidence has supported plant extracts and natural plant derivatives as promising antitumor therapy with less toxic side effects. Yuanhuacine is an active component isolated from Daphne genkwa and can effectively suppress the tumorigenesis of several cancers. However, its role in PCa remains unclear. In this study, yuanhuacine dose-dependently inhibited the proliferation and induced apoptosis of PCa cells. Moreover, yuanhuacine also restrained the invasion and migration of PCa cells. Mechanically, yuanhuacine decreased the ubiquitination and degradation of p53 protein, and ultimately increased p53 levels, which was regulated by inhibiting the phosphorylation and total protein levels of mouse double minute 2 (MDM2). Moreover, elevation of MDM2 reversed the suppressive efficacy of yuanhuacine in PCa cell viability, invasion, and migration. The network pharmacologic and bioinformatics analysis confirmed that MDM2 might be a common target of D. genkwa and LINC00665. Furthermore, yuanhuacine inhibited LINC00665 expression. Upregulation of LINC00665 reversed yuanhuacine-mediated inhibition in MDM2 protein expression and suppressed p53 levels by enhancing its ubiquitination in yuanhuacine-treated cells. Importantly, the inhibitory effects of yuanhuacine on cell viability and metastatic potential were offset after LINC00665 elevation. Together, the current findings highlight that yuanhuacine may possess tumor-suppressive efficacy by inhibiting LINC00665-mediated MDM2/p53 ubiquitination signaling. Therefore, this study indicates that yuanhuacine may be a promising candidate for the treatment of PCa.

LINC00665 knockdown confers sensitivity in irradiated non-small cell lung cancer cells through the miR-582-5p/UCHL3/AhR axis.

BACKGROUND: The resistance to radiotherapy remains a major obstacle that limits the efficacy of radiotherapy in non-small cell lung cancer (NSCLC). This study aims to illustrate the molecular mechanism underlying the role of LINC00665 in the radiosensitivity of NSCLC, which involves ubiquitin C-terminal hydrolase L3 (UCHL3). METHODS AND RESULTS: The expression of UCHL3 was determined in clinical tissue samples collected from NSCLC patients and NSCLC cell lines. We found that UCHL3 overexpression occurred in both NSCLC tissues and cells, associated with poor prognosis in NSCLC patients. Mechanistically, UCHL3 stabilized aryl hydrocarbon receptor (AhR) protein through deubiquitination, thereby promoting PD-L1 expression. UCHL3 reduced the radiosensitivity of NSCLC cells by stabilizing AhR protein. Upstream microRNAs (miRNAs) and lncRNAs of UCHL3 were predicted by microarray profiling and validated by functional experiments. LINC00665 functioned as a sponge of miR-582-5p and thus up-regulated the expression of the miR-582-5p target UCHL3. Gain- and loss- of function assays were performed to assess the effects of LINC00665, UCHL3 and miR-582-5p on the in vitro cell malignant behaviors and immune escape as well as on the in vivo tumor growth. Silencing LINC00665 or overexpressing miR-582-5p enhanced the sensitivity of NSCLC cells to radiotherapy. LINC00665 augmented the immune escape of NSCLC cells in vitro and in vivo through stabilizing AhR protein via the miR-582-5p/UCHL3 axis. CONCLUSIONS: Overall, LINC00665 reduced the radiosensitivity of NSCLC cells via stabilization of AhR through the miR-582-5p/UCHL3 axis.

LINC00665 up-regulates SIN3A expression to modulate the progression of colorectal cancer via sponging miR-138-5p.

BACKGROUND: Colorectal cancer (CRC) is a malignant tumor affecting people worldwide. Long noncoding RNAs (lncRNAs) is a crucial factor modulating various cancer progression, including CRC. Long intergenic non-protein coding RNA 665 (LINC00665) has been proven as an oncogene in several cancers, but its function in CRC is still unclear. METHODS: QRT-PCR was performed for RNA quantification. Functional assays were designed and carried to test cell phenotype while mechanism experiments were adopted for detecting the interaction of LINC00665, microRNA-138-5p (miR-138-5p) and SIN3 transcription regulator family member A (SIN3A). In vivo experiments were conducted to test LINC00665 function on modulating CRC tumor progression. RESULTS: LINC00665 displayed high expression in CRC tissues and cells, and promoted tumor progression in vivo. MiR-138-5p displayed abnormally low expression in CRC, and was verified to be sponged by LINC00665. Furthermore, SIN3A, as the downstream mRNA of miR-138-5p, exerted promoting impacts on CRC cells. Rescue experiments certified that overexpressed SIN3A or silenced miR-138-5p could offset the repressed function of LINC00665 knockdown on CRC progression. CONCLUSIONS: LINC00665 could sponge miR-138-5p to up-regulate SIN3A expression, thus accelerating CRC progression.

Long non-coding RNA LINC00665 promotes melanoma cell growth and migration via regulating the miR-224-5p/VMA21 axis.

Melanoma is an aggressive malignant skin tumor endangering the health of patients. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been increasingly reported to be implicated in the carcinogenesis of melanoma. Long intergenic non-coding RNA 00665 (LINC00665) has been found to exert important regulatory roles in some cancers, yet its function in melanoma remains to be investigated. QRT-PCR analysis was conducted to evaluate the relative expression of RNAs. Functional experiments in vitro including colony formation, EdU, wound-healing and transwell assays, as well as in vivo xenograft assays, were utilized to study the role of LINC00665 in melanoma. Mechanical experiments were implemented to probe into the molecular linkage of LINC00665, miR-224-5p and VMA21. LINC00665 was abnormally highly expressed in melanoma cells. Silencing LINC00665 could inhibit the proliferation and migration of melanoma cells. LINC00665 sponged miR-224-5p to upregulate VMA21. VMA21 knockdown exerted similarly interfering effects on above biological processes in melanoma cells. However, VMA21 overexpression abolished the in vitro and in vivo outcomes of LINC00665 silencing. LINC00665 promotes proliferative and migrating abilities of melanoma cells via targeting miR-224-5p/VMA21 axis.

Silencing LINC00665 inhibits cutaneous melanoma in vitro progression and induces apoptosis via the miR-339-3p/TUBB.

BACKGROUND: LncRNAs are closely related to cutaneous melanoma (CM) tumorigenesis and metastasis, and it can affect the progression of CM by regulating cell proliferation, migration, invasion, apoptosis, and other cellular mechanisms. This study investigated the role of LINC00665 in CM. METHODS: Expressions of LINC00665, miR-339-3p, and tubulin beta chain (TUBB) in CM cells were analyzed by qRT-PCR and/or Western blot. The LINC00665/miR-339-3p/TUBB targeting network was predicted by bioinformatics tools, screened out by Venn diagrams and analyzed by Pearson's correlation coefficients, followed by validation via dual-luciferase reporter assay and/or pull-down assay. Transfection of siLINC00665 or miR-339-3p inhibitor/mimic was conducted with CM cells whose viability, proliferation, migration, invasion, cell cycle progression, and apoptosis were measured by CCK-8 assay, colony formation assay, wound healing assay, Transwell assay, and flow cytometry. The associations of TUBB with tumor biological characteristics and other proteins were analyzed by CanserSEA and String, respectively. RESULTS: High-expressed LINC00665 was detected in CM cells. Silencing LINC00665 decreased CM cell viability; inhibited colony formation, cell cycle progression, migration and invasion; enhanced apoptosis; and upregulated miR-339-3p. LINC00665 targeted miR-339-3p which targeted TUBB. MiR-339-3p upregulation induced effects similar to the LINC00665-silencing-induced effects and could downregulate TUBB, which was associated with malignant behaviors and related to other five proteins. MiR-339-3p downregulation induced the opposite effects of what miR-339-3p upregulation induced, and the miR-339-3p downregulation-induced effects could be reversed by LINC00665 silencing. CONCLUSION: Silencing LINC00665 inhibits in vitro CM progression and induces apoptosis via the miR-339-3p/TUBB axis.

LINC00665 enhances tumorigenicity of endometrial carcinoma by interacting with high mobility group AT-hook 1.

BACKGROUND: Endometrial carcinoma is a frequently diagnosed cancer among females. LncRNAs are reported to be associated with various cancers. Their biological roles in endometrial carcinoma progression is an emerging scientific area. LINC00665 can exert a significant role in many cancers. However, its potential function in endometrial carcinoma is still poorly known. METHOD: qRT-PCR was carried out to test expression of LINC00665 and HMGA1. Western blot analysis was carried out to detect protein expression of HMGA1. Cell proliferation was evaluated using Cell Counting Kit-8 (CCK-8) and EdU assay. Flow cytometry assay was used to determine cell apoptosis and cell cycle. Wound healing and transwell invasion assay was carried out to test cell migration and invasion. Immunohistochemical staining and HE staining were conducted to assess Ki-67 and tumor growth respectively. RESULTS: Expression of LINC00665 in clinical endometrial carcinoma tissues and cells was obviously up-regulated. Loss of LINC00665 could repress endometrial carcinoma cell viability, induce cell apoptosis and block cell cycle in G1 phase. KLE and HHUA cell migration and invasion ability were depressed by LINC00665 shRNA. Decrease of LINC00665 suppressed endometrial carcinoma tumorigenicity in vivo. RIP assay proved that LINC00665 directly bound with HMGA1 protein. shRNA of HMGA1 obviously restrained endometrial carcinoma cell growth and cell invasion. CONCLUSIONS: LINC00665 might promote endometrial carcinoma progression by positively modulating HMGA1.

LINC00665 activates Wnt/ß-catenin signaling pathway to facilitate tumor progression of colorectal cancer via upregulating CTNNB1.

Background LINC00665 is a newly identified oncogene, which has been reported to be oncogene in various cancers. Nevertheless, its role in the progression of colorectal cancer (CRC) remains obscure to the extent. This study aimed at exploring the role and mechanism of LINC00665 in CRC progression. Materials and methods RNA and protein expression were detected via qRT-PCR and western blot. Functional assays were conducted to investigate the role of LINC00665 in the CRC cellular processes. TOP/FOP assay was performed to detect the activity of Wnt/ß-catenin signaling pathway. Mechanism investigations were carried out to explore the regulatory relationship among genes. Results LINC00665 was overtly expressed in CRC cell lines at high levels. Functionally, silencing of LINC00665 could curb in vitro CRC cell growth, migration and invasion, while stimulating cell apoptosis. Mechanically, LINC00665 sponged miR-214-3p to up-regulate CTNNB1 expression, consequently activating Wnt/ß-catenin signaling pathway. Furthermore, LINC00665 could bind to U2AF2 and enhance the association between U2AF2 and CTNNB1, increasing the stability of CTNNB1. CTNNB1 overexpression could reverse the suppressive effects of LINC00665 downregulation. Conclusion LINC00665 stimulates CRC progression through the activation of Wnt/ß-catenin signaling pathway, which hopefully might be a therapeutic target for CRC.

LINC00665 knockdown protects against cerebral ischemia-reperfusion injury.

LINC00665 has been reported to participate in several human diseases. However, the role of LINC00665 in cerebral ischemia-reperfusion (CI/R) is still unknown. This study is designed to investigate the role of LINC00665 in rats with CI/R injury. We established middle cerebral artery occlusion/ reperfusion (MCAO/R) rats model in vivo. PC12 cells treated with oxygen-glucose deprivation/reperfusion (OGD/R) were used to establish in vitro I/R model. RT-qPCR assay was adopted to assess the mRNA expression of LINC00665 and miR-744-5p. MTT assay was used to determine cell viability. The protein expression of Bax and Bcl-2 were detected by Western blot assay. The relationship between LINC00665 and miR-744-5p was confirmed by dual luciferase reporter assay and RNA immunoprecipitation (RIP). In this study, we found that LINC00665 was sharply up regulated in MCAO/R rats and PC12 cells treated with I/R. Functionally, LINC00665 knockdown attenuated oxidative damage in PC12 cells treated with I/R. Moreover, LINC00665 knockdown promoted cell viability, while inhibited cell apoptosis in PC12 cells treated with I/R. In addition, miR-744-5p was confirmed to be a target of LINC00665. LINC00665 knockdown was validated to project CI/R injury by sponging miR-744-5p expression.

LINC00665 induces gastric cancer progression through activating Wnt signaling pathway.

Long noncoding RNAs (lncRNAs) are recently recognized as noteworthy regulators of different tumors, counting gastric cancer (GC). Lately, long intergenic noncoding RNA (LINC) 00665 has been verified to display significant parts in several cancers. Be that as it may, its role and mechanism in GC movement still stay uninvestigated. As of now, we observed LINC00665 was obviously GC cells (MKN28, BGC-823, SGC7-901, AGS, HGC-27) in comparison to GES-1 cells, which was identified as human normal gastric epithelial cells. Then, LINC00665 was obviously downregulated in GC cells including AGS and BGC-823 cells. Loss of LINC00665 greatly repressed AGS and BGC-823 cell survival and cell expansion. Moreover, GC cell apoptosis was significantly induced by the loss of LINC00665. For another, we found that the GC cell cycle was also captured in G1 and G2 phases. The experiments on cell migration and invasion indicated that knockdown of LINC00665 restrained GC cell migration and invasion. Modifications in Wnt signaling are closely associated with the development of cancers. Here, we found that Wnt signaling was significantly inactivated by the silence of LINC00665 in GC cells. ß-catenin and cyclinD1 were restrained whereas GSK-3ß was induced by the inhibition of LINC00665 in GC cells. Furthermore, we confirmed the impact of LINC00665 in vivo using xenograft models. Taken these together, we indicated that LINC00665 could function as a novel biomarker in GC progression.

Long non-coding RNA linc00665 interacts with YB-1 and promotes angiogenesis in lung adenocarcinoma.

Angiogenesis is a core hallmark of advanced cancers, especially in lung adenocarcinoma (LUAD). However, the underlying functions and mechanisms of lncRNAs in tumor angiogenesis remain largely unknown. Here we found that linc00665 depletion could markedly depressed proliferation and capillary tube formation of HUVECs in vitro. Mechanistically, linc00665 directly interacted with YB-1 protein, enhanced its stability through inhibiting ubiquitination-dependent proteolysis and stimulated its nuclear translocation in LUAD cells. The accumulated nuclear YB-1 activated expression of ANGPT4, ANGPTL3 and VEGFA by binding to their promoters, contributing to tumor-related angiogenesis in vitro and in vivo. Collectively, we conclude that linc00665 induces tumor-related angiogenesis in LUAD by directly interacting with YB-1 and activating YB-1-ANGPT4/ANGPTL3/VEGFA axis, which provides promising anti-angiogenic targets for cancer therapy.

Knockdown of LINC00665 inhibits proliferation and invasion of breast cancer via competitive binding of miR-3619-5p and inhibition of catenin beta 1.

BACKGROUND: Long intergenic non-protein coding RNA00665 (LINC00665) plays a crucial tumorigenic role in many cancers, such as gastric cancer and lung adenocarcinoma. However, its role and mechanism of action in the progression of breast cancer (BC) are unknown. METHODS: LINC00665 expression levels were determined using quantitative polymerase chain reaction analysis with BC tissues and cell lines. BC cell proliferation was tested by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, whereas BC cell migration and invasion capabilities were analyzed by performing transwell migration assays. Percentages of apoptotic cells were measured by flow cytometry. Interactions between LINC00665 and miR-3169-5p were examined by performing luciferase reporter assays, and the expression levels of proteins, such as ß-catenin, were examined by western blot analysis. RESULTS: LINC00665 was expressed at high levels in BC tissues and cells. Upregulated LINC00665 expression correlated with tumor size and tumor, node, and metastasis stages, but not with the age of patients. LINC00665 knockdown inhibited BC cell proliferation, migration, and invasion, whereas it promoted apoptosis. Moreover, bioinformatics analysis and the luciferase reporter assay revealed that LINC00665 bound the microRNA (miR) miR-3619-5p. miR-3619-5p expression correlated negatively with LINC00665 expression in BC tissues. miR-3619-5p overexpression inhibited BC cell proliferation, migration, and invasion, but promoted apoptosis. Simultaneous knockdown of LINC00665 and miR-3619-5p led to increased cell proliferation, migration, and invasion, and inhibited apoptosis. Additionally, catenin beta 1, which encodes the ß-catenin protein, was the target gene of miR-3619-5p. ß-catenin expression clearly decreased after LINC00665 knockdown and miR-3619-5p overexpression, but increased after simultaneous knockdown of LINC00665 and miR-3619-5p. CONCLUSION: LINC00665 knockdown inhibited BC cell proliferation and invasion by binding miR-3619-5p and inhibiting ß-catenin expression.

[Retracted] LINC00665 functions as a competitive endogenous RNA to regulate AGTR1 expression by sponging miR­34a­5p in glioma.

Following the publication of the above paper, it was drawn to the Editor's attention by a concerned reader that the 'Control' data panel shown for the EdU assay experiment in Fig. 6D on p. 1209 was strikingly similar to a data panel featured in Fig. 7 that had already been submitted to the journal Cancer Management and Research by different authors at different research institutes [Chen T­J, Gao F, Yang T, Li H, Li Y, Ren H and Chen M­W: Knockdown of linc­POU3F3 suppresses the proliferation, apoptosis, and migration resistance of colorectal cancer. Cancer Manag Res 12: 4379­4390, 2020]. Owing to the fact that contentious data in the above article had already been submitted for publication prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 45: 1202­1212, 2021; DOI: 10.3892/or.2021.7949].

LINC00665 target let-7i/HMGA1 promotes the proliferation and invasion of hepatoma cells.

OBJECTIVES: Our group previously found that LINC00665 was upregulated in hepatocellular carcinoma (HCC) tissues through database analysis; however, the potential molecular mechanism of LINC00665 in HCC progression still needs further study. METHODS: qRTPCR was performed to determine the differential expression of LINC00665 and let-7i in HCC cells. Dual-luciferase reporter assays were performed to analyze the interaction of LINC00665 and let-7i. CCK-8 assays, scratch assays, Transwell invasion assays, qRTPCR and western blotting were performed to determine the regulatory mechanism of LINC00665/let-7i/HMGA1 in HCC cells. RESULTS: LINC00665 was upregulated in HCC cells compared with normal hepatocytes. A potential binding site between LINC00665 and let-7i was confirmed by dual-luciferase reporter assay. In HCC cells, inhibition of LINC00665 significantly reduced cell proliferation, migration and invasion ability via the let-7i/HMGA1 signaling axis. CONCLUSION: LINC00665 promotes the proliferation and invasion of HCC cells via the let-7i/HMGA1 signaling axis.

STAU1-mediated CNBP mRNA degradation by LINC00665 alters stem cell characteristics in ovarian cancer.

BACKGROUND: To investigate the role of lncRNA LINC00665 in modulating ovarian cancer stemness and its influence on treatment resistance and cancer development. METHODS: We isolated ovarian cancer stem cells (OCSCs) from the COC1 cell line using a combination of chemotherapeutic agents and growth factors, and verified their stemness through western blotting and immunofluorescence for stem cell markers. Employing bioinformatics, we identified lncRNAs associated with ovarian cancer, with a focus on LINC00665 and its interaction with the CNBP mRNA. In situ hybridization, immunohistochemistry, and qPCR were utilized to examine their expression and localization, alongside functional assays to determine the effects of LINC00665 on CNBP. RESULTS: LINC00665 employs its Alu elements to interact with the 3'-UTR of CNBP mRNA, targeting it for degradation. This molecular crosstalk enhances stemness by promoting the STAU1-mediated decay of CNBP mRNA, thereby modulating the Wnt and Notch signaling cascades that are pivotal for maintaining CSC characteristics and driving tumor progression. These mechanistic insights were corroborated by a series of in vitro assays and validated in vivo using tumor xenograft models. Furthermore, we established a positive correlation between elevated CNBP levels and increased disease-free survival in patients with ovarian cancer, underscoring the prognostic value of CNBP in this context. CONCLUSIONS: lncRNA LINC00665 enhances stemness in ovarian cancer by mediating the degradation of CNBP mRNA, thereby identifying LINC00665 as a potential therapeutic target to counteract drug resistance and tumor recurrence associated with CSCs.

Overexpression of lncRNA LINC00665 inhibits the proliferation and chondroblast differentiation of bone marrow mesenchymal stem cells by targeting miR-214-3p.

BACKGROUND: Osteoarthritis is a chronic disease mainly involving the damage of articular cartilage and the whole articular tissue, which is the main cause of disability in the elderly. To explore more effective treatment measures, this study analyzed the regulatory role and molecular mechanism of lncRNA LINC00665 (LINC00665) in the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), providing a valuable theoretical basis for the pathogenesis and patient treatment of osteoarthritis. METHODS: Osteoarthritis tissues and healthy tissues were obtained from 52 patients with osteoarthritis and 34 amputated patients without osteoarthritis, and the levels of LINC00665 and miR-214-3p were assessed by RT-qPCR. BMSCs were cultured and induced chondrogenic differentiation. The proliferation ability of BMSCs was detected by CCK-8 method, and the apoptosis level of BMSCs was evaluated by flow cytometry. The content of proteoglycan-glycosaminoglycan (GAG) in cartilage matrix was determined by Alcian blue staining. In addition, the binding relationship between LINC00665 and miR-214-3p was verified by luciferase reporter assay, and the molecular mechanism was further analyzed. RESULTS: In osteoarthritis tissues, LINC00665 was elevated and miR-214-3p was down-regulated. With the chondrogenic differentiation of BMSCs, the level of GAG increased, and LINC00665 expression gradually decreased, while miR-214-3p level was on the contrary. After transfection of pcDNA3.1-LINC00665 in BMSCs, cell proliferation capacity was decreased, apoptosis rate was increased, and GAG content was reduced. Moreover, LINC00665 sponged miR-214-3p and negatively regulate its expression. Transfection of pcDNA3.1-LINC00665-miR-214-3p mimic changed the regulation of pcDNA3.1-LINC00665 on the viability and chondrogenic differentiation of BMSCs. CONCLUSIONS: Overexpression of lncRNA LINC00665 inhibited the proliferation and chondrogenic differentiation of BMSCs by targeting miR-214-3p. The LINC00665/miR-214-3p axis may improve joint damage and alleviate the progression of osteoarthritis.

Prognostic and clinicopathological values of LINC00665 in cancers: a systematic review and China population-based meta-analysis.

BACKGROUND: Recent studies have uncovered that the aberrant expression of LINC00665 contributes to the malignant pathological process of various cancers and is closely related to the unfavorable prognosis of patients with cancer. However, a systematic analysis of the prognostic and clinicopathologic values of LINC00665 in cancers has not been conducted. OBJECTIVE: We aim to clarify the association of LINC00665 expression with patient survival and clinicopathologic phenotypes in cancers. METHODS: An electronic search of PubMed, Embase and Web of Science was performed to select eligible literature. Pooled hazard ratio (HR) and odds ratio (OR) were calculated to assess the clinical importance of LINC00665. The fixed-effects model was used to analyze the combined HR values and 95% CI when the studies had no significant heterogeneity (P > 0.1 for the Chi-square test or I2 < 50%). Begg's test and sensitivity analysis were also conducted. This study was registered in The International Prospective Register of Systematic Reviews (PROSPERO registration number: CRD42021290123). RESULTS: A total of 710 patients from 10 eligible studies were enrolled in this meta-analysis, which was based on China population. The pooled results of this analysis revealed that high-level expression of LINC00665 was notably correlated with poor overall survival (HR = 2.08, 95% CI = 1.57-2.75) and recurrence-free survival (HR = 2.49, 95% CI = 1.63-3.80) in human cancers. Elevated LINC00665 expression was also correlated with more advanced clinical stage, earlier lymph node metastasis, lower tumor differentiation, earlier distant metastasis and larger tumor size. CONCLUSION: LINC00665 expression was critically related to the cancer prognosis, which has important prognostic implications for clinical prediction.

Long noncoding RNA LINC00665 is a diagnostic biomarker that enhances cell proliferation and migration in hepatocellular carcinoma.

BACKGROUND: This study aimed to evaluate the relationship between LINC00665 expression levels and the risk of hepatocellular carcinoma (HCC) in Chinese Han nationality patients and to explore the influence of LINC00665 dysregulation on the proliferation and migration potential of HCC cells. PATIENTS AND METHODS: We investigated the expression of LINC00665 in The Cancer Genome Atlas (TCGA) database. Then, we confirmed the expression of LINC00665 in 54 pairs of surgical tissues from HCC patients and in liver cancer cell lines by quantitative real-time polymerase chain reaction. Furthermore, we manipulated the expression level of LINC00665 and examined the cell proliferation and migration abilities of HCC cells. RESULTS: In the TCGA cohort, a high level of LINC00665 in patients with HCC was significantly associated with tumor stage, tumor differentiation grade, and overall survival. In our HCC patient cohort, overexpression of LINC00665 in patients showed positive correlations with alpha-fetoprotein level, Barcelona Clinic Liver Cancer stage, and tumor differentiation grade. In addition, LINC00665 was upregulated in HCC cells, especially in cells with rapid growth rates and high migration abilities. A new LINC00665 isoform with a length of 1,371 nucleotides was identified in MHCC-97H cells. Interfering with LINC00665 expression weakened the proliferation and migration abilities of HCC cells. In contrast, LINC00665 overexpression enhanced proliferation and migration abilities. CONCLUSION: LINC00665 was upregulated in HCC tissues and cells and might be used to predict a poor prognosis of HCC patients. In addition, LINC00665 may promote the malignant progression of HCC by enhancing proliferation and migration capacities.

Thymidine kinase 1 as a target is regulated by the hsa-let-7b-5p/LINC00665 axis and affects NSCLC prognosis.

Background: In the past, multiple studies have offered incremental evidence that indicates that competitive endogenous RNA (ceRNA) regulatory networks are involved in tumor growth and present novel therapeutic targets. Herein, we investigated the impact of thymidine kinase 1 (TK1)-related ceRNA networks on the prognosis of non-small cell lung cancer (NSCLC). Methods: TK1 expression data in NSCLC and normal tissue samples were retrieved from the Cancer Genome Atlas (TCGA) database and were then compared. Thereafter, the findings of the immunohistochemical staining experiments and clinical follow-up data derived from patients with NSCLC were used for conducting prognostic analysis. The starBase database was searched to determine TK1-targeted microRNAs and long non-coding RNAs, and clinical data from TCGA were used for survival analysis to construct a ceRNA network associated with TK1 expression and prognosis. Finally, the roles played by methylation and immunity in the prognosis and treatment of NSCLC were analyzed. Results: Our findings revealed that the cancer tissues expressed significantly higher TK1 levels than normal tissues, and the follow-up clinical data revealed that the prognosis was generally worse in the high-expression patients than in the low-expression patients. In addition, clinical data collected from the starBase and TCGA databases showed that the LINC00665/has-let-7b-5p/TK1 network could influence the growth and prognosis of NSCLC. It was also noted that the TK1 methylation site was correlated with the prognosis of NSCLC, and immunoprognostic analysis further indicated that patients with higher TK1 expression levels displayed a worse prognosis. Conclusion: When the regulatory network of LINC00665/has-let-7b-5p/TK1 was assessed, it was observed that elevated TK1 levels may affect the prognosis of NSCLC. Therefore, it could be considered a prognostic biomarker and a probable therapeutic target for predicting NSCLC prognosis.