Circ_0001821 knockdown suppresses growth, metastasis, and TAX resistance of non-small-cell lung cancer cells by regulating the miR-526b-5p/GRK5 axis

CircSFMBT2 Plays an Oncogenic Role in Lung Adenocarcinoma Depending on the miR-1305/SALL4 Axis

Circular RNAs (circRNAs) exhibit significant functions in diverse malignant tumors, including lung adenocarcinoma (LUAD). In this study, we aimed to elucidate the role of circRNA scm like with four mbt domains 2 (circSFMBT2) in LUAD. Quantitative real-time polymerase chain reaction (qRT-PCR), western blot assay or immunohistochemistry (IHC) assay was performed for quantification of circSFMBT2, microRNA-1305 (miR-1305), spalt like transcription factor 4 (SALL4), proliferating Cell Nuclear Antigen (PCNA) or Ki-67. 5-ethynyl-2'-deoxyuridine (EdU) assay, transwell assay and flow cytometry analysis were applied to analyze cell proliferation, metastasis and apoptosis, respectively. Mouse xenograft model was established to explore the function of circSFMBT2. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to estimate the relationship between miR-1305 and circSFMBT2 or SALL4. CircSFMBT2 was upregulated in LUAD and related to advanced TNM stage and poor prognosis. CircSFMBT2 knockdown suppressed cell proliferation, metastasis, glycolysis and induced apoptosis in LUAD cells in vitro as well as tumor formation in vivo. CircSFMBT2 directly targeted miR-1305, and miR-1305 inhibition reversed circSFMBT2 knockdown-mediated inhibitory effects on LUAD malignant behaviors. SALL4 was the target gene of miR-1305. MiR-1305 overexpression repressed the malignant phenotypes of LUAD cells, while SALL4 enhancement abated the effects. CircSFMBT2 aggravated the progression of LUAD by the miR-1305/SALL4 axis, which might provide a diagnostic and prognostic marker for LUAD.

miRNAs and exosomal miRNAs in lung cancer: New emerging players in tumor progression and therapy response

Non-coding RNAs have shown key roles in cancer and among them, short RNA molecules are known as microRNAs (miRNAs). These molecules have length less than 25 nucleotides and suppress translation and expression. The functional miRNAs are produced in cytoplasm. Lung cancer is a devastating disease that its mortality and morbidity have undergone an increase in recent years. Aggressive behavior leads to undesirable prognosis and tumors demonstrate abnormal proliferation and invasion. In the present review, miRNA functions in lung cancer is described. miRNAs reduce/increase proliferation and metastasis. They modulate cell death and proliferation. Overexpression of oncogenic miRNAs facilitates drug resistance and radio-resistance in lung cancer. Tumor microenvironment components including macrophages and cancer-associated fibroblasts demonstrate interactions with miRNAs in lung cancer. Other factors such as HIF-1α, lncRNAs and circRNAs modulate miRNA expression. miRNAs have also value in the diagnosis of lung cancer. Understanding such interactions can pave the way for developing novel therapeutics in near future for lung cancer patients.

LINC01343 targets miR-526b-5p to facilitate the development of hepatocellular carcinoma by upregulating ROBO1

Long noncoding RNAs (lncRNAs) contribute to hepatocellular carcinoma (HCC) progression and development. However, the function and molecular mechanisms of action of LINC01343 in HCC remain unclear. qRT-PCR and western blotting were performed to assess miR-526b-5p, LINC01343, and ROBO1 levels in HCC cell lines and tissue samples. Flow cytometry, transwell, and cell counting kit-8 assays were conducted in vitro to assess how LINC01343 influences the apoptosis, migration, and proliferation of HCC cells. In addition, the role of LINC01343 in the growth of tumors was verified using an in vivo xenograft tumor assay. Specific binding of miR-526b-5p to LINC01343/ROBO1 was validated using RNA immunoprecipitation and dual-luciferase reporter experiments. LINC01343 was upregulated in HCC cells and tissues. In vitro, LINC01343-knockdown Hep3B and Huh-7 cells exhibited enhanced apoptosis and suppressed proliferation and migration. An in vivo study further validated that LINC01343-knockdown repressed tumor growth. In terms of mechanisms, LINC01343 directly sponged miR-526b-5p, negatively modulating its expression. Moreover, further experiments revealed that inhibiting miR-526b-5p could counteract the tumor-suppressive effects of LINC01343-knockdown in Hep3B and Huh-7 cells. ROBO1 was identified as a direct target of miR-526b-5p. ROBO1 knockdown weakens the migratory and proliferative abilities of Hep3B and Huh-7 cells. Nonetheless, the inhibition of miR-526b-5p mitigated this effect. These findings revealed that LINC01343 serves as a vital oncogene in HCC. Moreover, the LINC01343/miR-526b-5p/ROBO1 axis may be a prospective target for HCC treatment.

Circ_0001715 Functions as a miR-1249-3p Sponge to Accelerate the Progression of Non-small Cell Lung Cancer via Upregulating the Level of FGF5

Circular RNAs (circRNAs) have been widely involved in the malignant development of human cancers. Circ_0001715 was aberrantly upregulated in non-small cell lung cancer (NSCLC). However, circ_0001715 function has never been researched. This study was designed to investigate the role and mechanism of circ_0001715 in NSCLC. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to examine the levels of circ_0001715, microRNA-1249-3p (miR-1249-3p) and Fibroblast Growth Factor 5 (FGF5). The proliferation detection was conducted using colony formation assay and EdU assay. Cell apoptosis was analyzed via flow cytometry. Wound healing assay and transwell assay were used for determination of migration and invasion, respectively. The protein levels were measured through western blot. Target analysis was carried out via dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Xenograft tumor model was established in mice for in vivo research. The significant upregulation of circ_0001715 was detected in NSCLC samples and cells. Circ_0001715 knockdown induced the inhibitory effects on proliferation, migration and invasion but the promoting effect on apoptosis of NSCLC cells. Circ_0001715 could interact with miR-1249-3p. The regulatory role of circ_0001715 was achieved by sponging miR-1249-3p. Furthermore, miR-1249-3p targeted FGF5 and miR-1249-3p acted as a cancer inhibitor by targeting FGF5. Moreover, circ_0001715 upregulated the FGF5 level via targeting miR-1249-3p. In vivo assay showed that circ_0001715 promoted the NSCLC progression through the miR-1249-3p/FGF5 axis. The current evidence elucidated that circ_0001715 served as an oncogenic regulator in NSCLC progression by depending on the miR-1249-3p/FGF5 axis.

Hsa_circ_0003489 Drives PTX Resistance of Human NSCLC Cells Through Modulating miR-98-5p/IGF2

Background

Circular RNAs (circRNAs) demonstrated critical roles within developing tumors and treatment resistance in an increasing body of research. The aim was to look into the functions and processes of hsa_circ_0003489 in the non-small cell lung cancer (NSCLC) paclitaxel (PTX) resistance.

Methods

NSCLC cell-based cultures including A549 and H460 were employed for such an investigation. hsa_circ_0003489, miR-98-5p, and insulin-like growth factor 2 (IGF2) expression-profiles were evaluated with a quantitative real-time polymerase chain reaction (RT-qPCR). The PTX resistance was determined using MTT assay, and the ELISA test measured IGF2 expression. Facilitating corroboration for miR-98-5p relation and hsa_circ_0003489 or IGF2, a dual-luciferase reporter method was applied.

Results

The hsa_circ_0003489 level was raised in cells and tissues from PTX-resistant (PR) NSCLC. In PR NSCLC cells, hsa_circ_0003489 knockdown reduced PTX resistance. For the purpose of the mechanism study, hsa_circ_0003489 knockdown substantially reduced IGF2 expression via miR-98-5p sponging, improving PTX sensitivity in PR NSCLC.

Conclusion

Through miR-98-5p/IGF2 axis control, hsa_circ_0003489 knockdown helped NSCLC overcome PTX resistance, suggesting a potential circRNA-targeted therapy for the disease.

Role of microRNAs in regulation of doxorubicin and paclitaxel responses in lung tumor cells

Lung cancer as the leading cause of cancer related mortality is always one of the main global health challenges. Despite the recent progresses in therapeutic methods, the mortality rate is still significantly high among lung cancer patients. A wide range of therapeutic methods including chemotherapy, radiotherapy, and surgery are used to treat lung cancer. Doxorubicin (DOX) and Paclitaxel (TXL) are widely used as the first-line chemotherapeutic drugs in lung cancer. However, there is a significant high percentage of DOX/TXL resistance in lung cancer patients, which leads to tumor recurrence and metastasis. Considering, the side effects of these drugs in normal tissues, it is required to clarify the molecular mechanisms of DOX/TXL resistance to introduce the efficient prognostic and therapeutic markers in lung cancer. MicroRNAs (miRNAs) have key roles in regulation of different pathophysiological processes including cell division, apoptosis, migration, and drug resistance. MiRNA deregulations are widely associated with chemo resistance in various cancers. Therefore, considering the importance of miRNAs in chemotherapy response, in the present review, we discussed the role of miRNAs in regulation of DOX/TXL response in lung cancer patients. It has been reported that miRNAs mainly induced DOX/TXL sensitivity in lung tumor cells by the regulation of signaling pathways, autophagy, transcription factors, and apoptosis. This review can be an effective step in introducing miRNAs as the non-invasive prognostic markers to predict DOX/TXL response in lung cancer patients.

miR-526b-5p/c-Myc/Foxp1 participates in recurrent spontaneous abortion by regulating the proliferation, migration, and invasion of trophoblasts

PURPOSE

As a member of the C19MC family, miR-526b-5p is mainly expressed in the placental tissue and is a well-known tumor suppressor microRNA. However, its effect on the function of trophoblasts and its role in the development of recurrent spontaneous abortion (RSA) remains unclear.

METHODS

Transcriptome sequencing, quantitative real-time polymerase chain reaction (RT-qPCR), Western blot, 5-ethynyl-2'-deoxyuridine (Edu) proliferation analysis, cell counting kit-8 (CCK8) assay, Transwell assays, and wound healing were used to detect the proliferation, migration, and invasion capacity of trophoblasts. Target genes of miR-526b-5p were obtained by the dual luciferase reporter system. The promoter-reporter system and ChIP-qPCR were used to prove that c-Myc positively regulated the expression of Foxp1 RESULTS: The miR-526b-5p levels were significantly higher in patients with RSA than in controls. High expression of miR-526b-5p inhibited the proliferation, migration, and invasion of trophoblast cell line. By contrast, low expression of miR-526b-5p promoted the proliferation and migration of trophoblast cell line. Target genes of miR-526b-5p were c-Myc and Foxp1. c-Myc positively regulated the expression of Foxp1 by binding to the Foxp1 promoter location -146/-135. Finally, miR-526b-5p impeded the proliferation, migration, and invasion of trophoblasts by negatively regulating c-Myc by rescue experiments.

CONCLUSION

Thus, miR-526b-5p affected the proliferation, migration, and invasion of trophoblasts by targeting c-Myc and Foxp1. Low expression of c-Myc further deactivated the positive transcriptional regulation of c-Myc on Foxp1, which may be the mechanism of RSA. This study provides potential therapeutic targets and clues for the diagnosis and treatment of RSA.

Circ_0001821 Potentiates Cell Growth, Metastasis, and Stemness in Colorectal Cancer by Regulating miR-339-3p/CST1

Dysregulation of circRNAs is associated with human cancer progression, but its expression pattern and function in cancer are not fully understood. The aim of our study is to investigate the effects of circ_0001821 on colorectal cancer (CRC) proliferation, migration, invasion, and stemness. The expression level of circ_0001821 in CRC tissues and cells was detected by quantitative real-time PCR. The effects of circ_0001821 silencing on the proliferation, migration, invasion, and stemness of CRC cells were examined by cell counting kit-8, 5-Ethynyl-2'-deoxyuridine, transwell, sphere formation, and western blot assays. Bioinformatics and dual-luciferase reporter gene assay were used to verify the relationship between circ_0001821 and miR-339-3p, miR-339-3p and CST1 in CRC cells. Circ_0001821 was highly expressed in CRC tissues and cells. Circ_0001821 silencing inhibited the proliferation, migration, invasion, and stemness of CRC cells, and transfection of miR-339-3p inhibitor partly attenuated this effect. In addition, circ_0001821 can bind miR-339-3p to regulate CST1 expression. Circ_0001821 silencing also curbed tumor growth in vivo. Circ_0001821 promoted CRC cell proliferation, migration, invasion, and stemness by regulating the miR-339-3p/CST1 axis.

CircPIM3 regulates taxol resistance in non-small cell lung cancer via miR-338-3p/TNFAIP8 axis

Numerous work has revealed the involvement of circular RNA (circRNA) in regulating chemotherapy resistance. Here, we investigate circPIM3 role in taxol (Tax) resistance in non-small cell lung cancer (NSCLC). CircPIM3, microRNA (miR)-338-3p and tumor necrosis factor-alpha-induced protein-8 (TNFAIP8) expression were detected via quantitative real-time PCR, western blot or immunohistochemistry assay. Tax resistance was evaluated using cell counting kit-8, cell proliferation was measured by colony formation assay, cell cycle and apoptosis were examined via flow cytometry. The interplay between miR-338-3p and circPIM3 or TNFAIP8 was confirmed by dual-luciferase reporter assay. Finally, the effect of circPIM3 on Tax resistance in NSCLC in vivo was investigated by xenograft models. CircPIM3 and TNFAIP8 were upregulated in Tax-resistant NSCLC tissue and cell samples. Reducing circPIM3 expression inhibited Tax resistance, proliferation and induced cycle arrest and apoptosis in Tax-resistant NSCLC cells. Mechanically, circPIM3 absence led to downregulation of TNFAIP8 via absorbing miR-338-3p. Additionally, circPIM3 depletion increased Tax sensitivity of NSCLC in vivo. Silencing of circPIM3 suppressed Tax resistance in Tax-resistant NSCLC cells through regulation of the miR-338-3p/TNFAIP8 axis.

The emerging role of circular RNAs in drug resistance of non-small cell lung cancer

Due to the characteristics of aggressiveness and high risk of postoperative recurrence, non-small cell lung cancer (NSCLC) is a serious hazard to human health, accounting for 85% of all lung cancer cases. Drug therapies, including chemotherapy, targeted therapy and immunotherapy, are effective treatments for NSCLC in clinics. However, most patients ultimately develop drug resistance, which is also the leading cause of treatment failure in cancer. To date, the mechanisms of drug resistance have yet to be fully elucidated, thus original strategies are developed to overcome this issue. Emerging studies have illustrated that circular RNAs (circRNAs) participate in the generation of therapeutic resistance in NSCLC. CircRNAs mediate the modulations of immune cells, cytokines, autophagy, ferroptosis and metabolism in the tumor microenvironment (TME), which play essential roles in the generation of drug resistance of NSCLC. More importantly, circRNAs function as miRNAs sponges to affect specific signaling pathways, directly leading to the generation of drug resistance. Consequently, this review highlights the mechanisms underlying the relationship between circRNAs and drug resistance in NSCLC. Additionally, several therapeutic drugs associated with circRNAs are summarized, aiming to provide references for circRNAs serving as potential therapeutic targets in overcoming drug resistance in NSCLC.

Role of circular RNAs in the diagnosis, regulation of drug resistance and prognosis of lung cancer (Review)

Lung cancer is one of the most common malignant tumors in China and is the highest cause of mortality among male and female patients, both in urban and rural areas. A subset of patients with lung cancer only display chest tightness without any other obvious symptoms. This is because most symptoms do not manifest during the early stages of disease development. Consequently, most patients with lung cancer are diagnosed when the disease is in the advanced stages, when they are already unfit for surgical treatment. Furthermore, the prognosis of patients with lung cancer is poor. The 5-year survival rate of patients with stage IA lung cancer is 85%, compared with 6% in those with stage IV. This requires the development of strategies for early diagnosis, treatment and prognosis to improve the management of lung cancer. Circular RNAs (circRNAs) belong to a class of closed circular non-coding RNAs formed by reverse splicing of a precursor mRNA. These RNAs are highly stable, ubiquitously expressed, conserved, and show high specificity. CircRNAs regulate biological processes, such as the proliferation, differentiation and invasion of lung cancer cells. Therefore, they can be used as biomarkers for the early diagnosis and prognosis prediction of lung cancer, as well as novel targets for therapy design. In the present review, the biological characteristics and functions of circRNAs, as well as their application in the diagnosis, control of drug resistance and effect on the prognosis of patients with lung cancer, will be discussed.

Advances in the Study of CircRNAs in Tumor Drug Resistance

Recent studies have revealed that circRNAs can affect tumor DNA damage and repair, apoptosis, proliferation, and invasion and influence the transport of intratumor substances by acting as miRNA sponges and transcriptional regulators and binding to proteins in a variety of ways. However, research on the role of circRNAs in cancer radiotherapy and chemoresistance is still in its early stages. Chemotherapy is a common approach to oncology treatment, but the development of tumor resistance limits the overall clinical efficacy of chemotherapy for cancer patients. The current study suggests that circRNAs have a facilitative or inhibitory effect on the development of resistance to conventional chemotherapy in a variety of tumors, suggesting that circRNAs may serve as a new direction for the study of antitumor drug resistance. In this review, we will briefly discuss the biological features of circRNAs and summarize the recent progression of the involvement of circRNAs in the development and pathogenesis of cancer chemoresistance.

Regulation of apoptosis, autophagy and ferroptosis by non‑coding RNAs in metastatic non‑small cell lung cancer (Review)

Non-small cell lung cancer (NSCLC), a common type of cancer worldwide, is normally associated with a poor prognosis. It is difficult to treat successfully as it often metastasizes into brain or bone. Methods to facilitate the induction of effective programmed cell death (PCD) in NSCLC cells to reverse drug resistance, or to inhibit the invasion and migration of NSCLC cells, are currently under investigation. The present study summarized the regulatory functions of PCD, including apoptosis, autophagy and ferroptosis, in the context of NSCLC metastasis. It further summarized how regulatory agents, including long non-coding RNAs, circular RNAs and microRNAs, regulate PCD during the metastasis of NSCLC and characterized new potential diagnostic biomarkers of NSCLC metastasis.

Circular RNA circ_0002360 regulates the Taxol resistance and malignant behaviors of Taxol-resistant non-small cell lung cancer cells by microRNA-585-3p-dependent modulation of G protein regulated inducer of neurite outgrowth 1

Drug resistance has become the major obstacle for the treatment of non-small cell lung cancer (NSCLC). Circular RNAs (circRNAs) are tightly linked to the development of drug resistance of NSCLC. Herein, we tested the function of circ_0002360 in the Taxol resistance of NSCLC. Circ_0002360, microRNA (miR)-585-3p and G protein regulated inducer of neurite outgrowth 1 (GPRIN1) were quantified by quantitative real-time PCR (qRT-PCR). To identify the circular structure of circ_0002360, RNase R digestion was applied. To detect cell proliferation, colony formation and 5-ethynyl-2’-deoxyuridine (EdU) assays were used. For assessment of cell apoptosis, flow cytometry was adopted. For motility and invasion analyses, transwell assay was employed. Our data showed that circ_0002360 was mainly located in the cytoplasm and was highly expressed in the Taxol-resistant NSCLC. Silencing of circ_0002360 inhibited cell Taxol resistance, proliferation, motility, and invasiveness and induced apoptosis in vitro. MiR-585-3p was underexpressed in Taxol-resistant NSCLC and was targeted by circ_0002360. MiR-585-3p knockdown alleviated the influence of circ_0002360 silence on Taxol-resistant cells. GPRIN1 was directly targeted by miR-585-3p. The influence of miR-585-3p on cell Taxol resistance and functional behaviors was reversed by GPRIN1 overexpression. Moreover, circ_0002360 modulated GPRIN1 through miR-585-3p. Additionally, silencing of circ_0002360 weakened the growth of xenografts in vivo. Our study demonstrated that silencing of circ_0002360 enhanced the Taxol sensitivity and suppressed the malignant behaviors of Taxol-resistant NSCLC cells by miR-585-3p/GPRIN1 axis, providing novel targets for improving the anti-tumor efficacy of Taxol in NSCLC.

The Role of Circular RNAs in the Drug Resistance of Cancers

Cancer is a major threat to human health and longevity. Chemotherapy is an effective approach to inhibit cancer cell proliferation, but a growing number of cancer patients are prone to develop resistance to various chemotherapeutics, including platinum, paclitaxel, adriamycin, and 5-fluorouracil, among others. Significant progress has been made in the research and development of chemotherapeutic drugs over the last few decades, including targeted therapy drugs and immune checkpoint inhibitors; however, drug resistance still severely limits the application and efficacy of these drugs in cancer treatment. Recently, emerging studies have emphasized the role of circular RNAs (circRNAs) in the proliferation, migration, invasion, and especially chemoresistance of cancer cells by regulating the expression of related miRNAs and targeted genes. In this review, we comprehensively summarized the potential roles and mechanisms of circRNAs in cancer drug resistance including the efflux of drugs, apoptosis, intervention with the TME (tumor microenvironment), autophagy, and dysfunction of DNA damage repair, among others. Furthermore, we highlighted the potential value of circRNAs as new therapeutic targets and prognostic biomarkers for cancer.