DDP-resistant Non-small Cell Lung Cancer Research Articles

Microsomal glutathione transferase 1 confers cisplatin resistance of non-small cell lung cancer via interaction with arachidonate lipoxygenase 5 to repress ferroptosis.

Cisplatin (DDP) resistance remains a primary cause of chemotherapy failure and recurrence of non-small cell lung cancer (NSCLC). Abnormal high microsomal glutathione transferase 1 (MGST1) expression has been found in DDP-resistant NSCLC cells. This study aimed to explore the function and mechanism of MGST1 in DDP resistance of NSCLC cells. The expression levels of target molecules were assessed by quantitative real-time polymerase chain reaction (RT-qPCR) and western blotting. Cell proliferation was evaluated by cell counting kit-8 (CCK-8) and colony formation assays. Ferroptosis was determined by malondialdehyde (MDA), glutathione (GSH), Fe2+, and reactive oxygen species (ROS) levels. The interaction between proteins was confirmed by Co-immunoprecipitation (Co-IP). The effect of MGST1 on DDP resistance was evaluated using the tumor xenograft assay in vivo. Immunohistochemical staining was performed to measure Ki-67 and p-H2A.X expression in tumor tissues. MGST1 expression was higher, while arachidonate lipoxygenase 5 (ALOX5) expression was lower in DDP-resistant NSCLC patients and cells. MGST1 ablation sensitized NSCLC cells to DDP therapy through inducing ferroptosis. MGST1 protein directly interacted with ALOX5 protein to restrain ALOX5-triggered ferroptosis. Ferroptosis inhibitor or sh-ALOX5 reversed the promotive effect of MGST1 silencing on the DDP sensitivity of NSCLC cells. Finally, MGST1 depletion sensitized NSCLC cells to DDP therapy in nude mice in vivo. MGST1 high expression contributed to DDP resistance of NSCLC cells by inhibiting ALOX5-induced ferroptosis. Our results provide a potential therapeutic target for overcoming DDP resistance in NSCLC patients.

USP5-dependent HDAC1 promotes cisplatin resistance and the malignant progression of non-small cell lung cancer by regulating RILP acetylation levels.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide, with cisplatin (DDP) resistance being a significant challenge in its treatment. Histone deacetylase 1 (HDAC1) has been implicated in the regulation of NSCLC progression; however, its role in the resistance of NSCLC to DDP remains unclear. The mRNA levels of HDAC1, ubiquitin specific peptidase 5 (USP5), and Rab interacting lysosomal protein (RILP) were analyzed by quantitative real-time polymerase chain reaction. The protein expression of HDAC1, multidrug resistance protein 1 (MRP1) and RILP was detected by western blotting assay or immunohistochemistry assay. The IC50 value of DDP was determined using a cell counting kit-8 assay, while cell proliferation, apoptosis, and invasion were assessed using 5-Ethynyl-2'-deoxyuridine assay, flow cytometry, and trans well invasion assay, respectively. Cancer stem-like cell properties were analyzed by a sphere formation assay. The interaction between USP5 andHDAC1 was investigated using MG132 assay and co-immunoprecipitation (Co-IP).RILP acetylation was analyzed by a Co-IP assay. A xenograft mouse model assay was employed to study the in vivo effects of HDAC1 silencing on DDP sensitivity. HDAC1 expression was upregulated in DDP-resistant NSCLC tissues and cells. Silencing HDAC1 enhanced the sensitivity of NSCLC cells to DDP, inhibited cell proliferation, invasion, and the formation of microspheres and induced cell apoptosis. USP5 was found to deubiquitinate and stabilize HDAC1 in DDP-resistant NSCLC cells. Moreover, HDAC1 overexpression reversed the effects induced by USP5 silencing. HDAC1 also sensitized Rab-interacting lysosomal protein (RILP) acetylation in DDP-resistant NSCLC cells, and RILP upregulation counteracted the effects of HDAC1 overexpression in DDP-resistant NSCLC cells. HDAC1 silencing also improved the sensitivity of tumors to DDP in vivo. USP5-dependentstabilization of HDAC1 contributed to cisplatin resistance and the malignancy of NSCLC by diminishing the levels of RILP acetylation, which suggested that targeting the HDAC1-USP5axis might represent a novel therapeutic strategy for overcoming DDP resistance in NSCLC patients.

ETS1 promotes cisplatin resistance of NSCLC cells by promoting GRP78 transcription.

Non-small cell lung cancer (NSCLC) is a common malignant tumor characterized by rapid growth and invasive power. Glucose regulatory protein 78 (GRP78) is important in cancer cell progression. Here, this study aimed to explore the effect and mechanism of GRP78 on cisplatin (DDP) resistance of NSCLC cells. qRT-PCR and Western blot detected the expression of genes and proteins. Flow cytometry was used to analyze endoplasmic reticulum stress (ERS) induced by DDP in NSCLC. Cell proliferation and apoptosis were examined using cell counting kit-8 (CCK8), cell cloning, and flow cytometry, respectively. Chromatin immunoprecipitation assay (CHIP) and dual-luciferase reporter assays were performed to determine the binding of ETS1 and GRP78 promoter. Mouse xenograft models were constructed for in vivo analysis. ERS was induced by DDP in NSCLC cells. GRP78 were upregulated in DDP-resistant NSCLC tissues, and knockdown of GRP78 suppressed DDP resistance, clone formation, promoted apoptosis, and inhibited ERS in DDP-resistant NSCLC cells. ETS1 knockdown repressed GRP78 expression and NSCLC tumor growth. Interestingly, ETS1 played a role in DDP-resistant NSCLC via GRP78. ETS1 inhibits cisplatin sensitivity of NSCLC cells by promoting GRP78 transcription.

LncRNA SH3PXD2A-AS1 facilitates cisplatin resistance in non-small cell lung cancer by regulating FOXM1 succinylation

BackgroundLong noncoding RNAs (lncRNAs) play vital regulatory functions in non-small cell lung cancer (NSCLC). Cisplatin (DDP) resistance has significantly decreased the effectiveness of DDP-based chemotherapy in NSCLC patients. This study aimed to investigate the effects of SH3PXD2A antisense RNA 1 (SH3PXD2A-AS1) on DDP resistance in NSCLC.MethodsProliferation and apoptosis of DDP-resistant NSCLC cells were detected using cell counting kit-8 and flow cytometry assays. The interaction between SH3PXD2A-AS1 and sirtuin 7 (SIRT7) was assessed using co-immunoprecipitation (Co-IP), RNA pull-down, RNA immunoprecipitation (RIP), RNA fluorescence in situ hybridization, and immunofluorescence assays, while succinylation (SUCC) of Forkhead Box M1 (FOXM1) was analyzed by IP and Western blot assays. The role of SH3PXD2A-AS1 in vivo was explored using a xenografted tumor model.ResultsExpression of SH3PXD2A-AS1 was found elevated in DDP-resistant NSCLC cells, while it’s knocking down translated into suppression of cell viability and promotion of apoptosis. Moreover, silencing of SH3PXD2A-AS1 resulted in decreased FOXM1 protein level and enhanced FOXM1-SUCC protein level. The SIRT7 was found to interact with FOXM1, translating into inhibition of FOXM1 SUCC at the K259 site in human embryonic kidney (HEK)-293T cells. Overexpressing of SIRT7 reversed the increase of FOXM1-SUCC protein level and apoptosis, and the decrease of cell viability induced by silencing of SH3PXD2A-AS1. In tumor-bearing mice, SH3PXD2A-AS1 inhibition suppressed tumor growth and the protein levels of Ki67, SIRT7, and FOXM1.ConclusionSH3PXD2A-AS1 promoted DDP resistance in NSCLC cells by regulating FOXM1 SUCC via SIRT7, offering a promising therapeutic approach for NSCLC.

Role and mechanism of COL3A1 in regulating the growth, metastasis, and drug sensitivity in cisplatin-resistant non-small cell lung cancer cells

ABSTRACT Non-small cell lung cancer (NSCLC) is among the most difficult malignancies to treat. Type III collagen (COL3A1) can affect the progression and chemoresistance development of NSCLC. We herein explored the mechanism that drives COL3A1 dysregulation in NSCLC. Potential RNA-binding proteins (RBPs) and transcription factors (TFs) that could bind to COL3A1 were searched by bioinformatics. mRNA expression was detected by quantitative PCR. Protein expression was evaluated using immunoblotting and immunohistochemistry. The effects of the variables were assessed by gauging cell growth, invasiveness, migratory capacity, apoptosis, and cisplatin (DDP) sensitivity. The direct YY1/COL3A1 relationship was confirmed by ChIP and luciferase reporter experiments. Xenograft experiments were done to examine COL3A1’s function in DDP efficacy. COL3A1 showed enhanced expression in DDP-resistant NSCLC. In H460/DDP and A549/DDP cells, downregulation of COL3A1 exerted inhibitory functions in cell growth, invasiveness, and migration, as well as promoting effects on cell DDP sensitivity and apoptosis. Mechanistically, ELAV-like RNA binding protein 1 (ELAVL1) enhanced the mRNA stability and expression of COL3A1, and Yin Yang 1 (YY1) promoted the transcription and expression of COL3A1. Furthermore, upregulation of COL3A1 reversed ELAVL1 inhibition- or YY1 deficiency-mediated functions in DDP-resistant NSCLC cells. Additionally, COL3A1 downregulation enhanced the anti-tumor efficacy of DDP in vivo. Our investigation demonstrates that COL3A1 upregulation, induced by both RBP ELAVL1 and TF YY1, exerts important functions in phenotypes of NSCLC cells with DDP resistance, offering an innovative opportunity in the treatment of drug-resistant NSCLC.

Circular RNA-AnnexinA7 accelerates cisplatin resistance in non-small cell lung cancer via modulating microRNA-545-3p to mediate Cyclin D1

Objective: To explore the mechanism of circular RNA (circRNA)-AnnexinA7 (ANXA7) in non-small cell lung cancer (NSCLC) cisplatin (DDP) resistance through microRNA (miR)-545-3p to target Cyclin D1 (CCND1). Methods: DDP-resistant and non-resistant NSCLC tissues and normal tissues were collected. DDP-resistant cells (A549/DDP and H460/DDP) were constructed. circ-ANXA7, miR-545-3p, CCND1, P-Glycoprotein, and glutathione S-transferase-π in tissues and cells were measured. Analysis of circ-ANXA7 ring structure was performed, as well as detection of circ-ANXA7 distribution in cells. Cell proliferation was detected by MTT and colony formation assay, apoptosis rate was detected by flow cytometry, and cell migration and invasion were evaluated by Transwell assay. The targeting relationship between circ-ANXA7, miR-545-3p and CCND1 was verified. Measurement of tumor volume and quality in mice was performed. Results: Circ-ANXA7 and CCND1 were elevated, while miR-545-3p was suppressed in DDP-resistant NSCLC tissues and cells. Circ-ANXA7 combined with miR-545-3p, which targeted CCND1 to expedite A549/DDP cell proliferation, migration, invasion, DDP resistance, but inhibited cell apoptosis. Conclusion: Circ-ANXA7 enhances DDP resistance in NSCLC via absorbing miR-545-3p to target CCND1 and might be a latent therapeutic target for NSCLC.

Circ_0110498 facilitates the cisplatin resistance of non-small cell lung cancer by mediating the miR-1287-5p/RBBP4 axis.

Circular RNAs (circRNAs) play vital roles in non-small cell lung cancer (NSCLC) progression. Our research analyzed the role of circ_0110498 on the cisplatin (DDP) resistance of NSCLC. Cell glycolysis was analyzed by measuring glucose consumption and lactate production. Protein expression was determined by western blot analysis. The expression of circ_0110498, microRNA (miR)-1287-5p and RBBP4 was detected by RT-qPCR assay. Cell counting kit-8, colony formation and transwell assays, together with flow cytometry were conducted to analyze cell DDP resistance, proliferation, metastasis and apoptosis. Circ_0110498 expression was elevated in DDP-resistant NSCLC tissues and cells. Circ_0110498 silencing not only suppressed the DDP resistance of NSCLC cells by inhibiting cell growth, metastasis and glycolysis, but also enhanced the DDP sensitivity of NSCLC tumors. MiR-1287-5p was sponged by circ_0110498, and its inhibitor also reversed the effect of circ_0110498 silencing on the DDP resistance of NSCLC cells. MiR-1287-5p interacted with RBBP4, and RBBP4 overexpression partly reversed the inhibitory effect of miR-1287-5p on the DDP resistance of NSCLC cells. Circ_0110498 facilitated DDP resistance partly through mediating the miR-1287-5p/RBBP4 signaling in NSCLC.

LncRNA SNHG7 promotes non-small cell lung cancer progression and cisplatin resistance by inducing autophagic activity.

Cisplatin (DDP) is among the most widely used chemotherapeutic drugs for non-small cell lung cancer (NSCLC), yet the frequent emergence of chemoresistance serves as a major barrier to the treatment of this tumor type. Long non-coding RNAs (lncRNAs) have recently been shown to influence the ability of cells to resist particular chemotherapy drugs. The present study was developed to explore the role of the lncRNA SNHG7 as a regulator of NSCLC cell chemosensitivity. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to measure SNHG7 expression in NSCLC tissues from patients that were sensitive/resistant to DDP, correlations between SNHG7 expression levels and the patients' clinicopathological characteristics were assessed, and the prognostic relevance of SNHG7 expression was examined via the Kaplan-Meier approach. In addition, SNHG7 expression was assessed in NSCLC cell lines that were DDP-sensitive or -resistant, while western blotting and immunofluorescence staining were employed to detect autophagy-associated protein expression in A549, A549/DDP, HCC827, and HCC827/DDP cells. NSCLC cell chemoresistance was quantified via the Cell Counting Kit-8 (CCK-8) assay approach, and flow cytometry was used to detect the apoptotic death of these tumor cells. The chemosensitivity of xenograft tumors in vivo was further assessed to validate the functional importance of SNHG7 as a regulator of NSCLC DDP resistance. Relative to paracancerous tissues, NSCLC tumors exhibited SNHG7 upregulation, and this lncRNA was further upregulated in DDP-resistant patients compared to chemosensitive patients. Consistently, higher SNHG7 expression levels were correlated with worse patient survival outcomes. DDP-resistant NSCLC cells were also found to exhibit higher levels of SNHG7 expression than chemosensitive cells, and knocking down this lncRNA enhanced the sensitivity of these cells to DDP treatment, resulting in impaired proliferation and higher rates of apoptotic death. Knocking down SNHG7 was also sufficient to suppress microtubule associated protein 1 light chain 3 beta (LC3B) and Beclin1 protein levels and promote p62 upregulation in vitro. The silencing of this lncRNA additionally inhibited the resistance of NSCLC xenograft tumors to DDP treatment in vivo. SNHG7 can promote malignant behaviors and DDP resistance in NSCLC cells at least partly via the induction of autophagic activity.

Circ_0030411 aggravates cisplatin-resistance in non-small cell lung cancer by serving as a miR-495-3p sponge to enhance CCND1 expression

Circular RNAsplay important modulators in cisplatin (DDP) resistant non-small cell lung cancer (NSCLC). Herein, the role and mechanism of circ_0030411 in DDP-resistant NSCLC was explored. Circ_0030411, miR-495-3p, CCND1, PCNA, Bax, E-cadherin, and ki-67 expression were examined byqRT-PCR, western blot and IHC. DDP resistance, cell proliferation, apoptosis, and motility were assessed usingCCK, EdU flow cytometry, and transwell. Xenograft tumour model was established to explore the role of circ_0030411 in DDP-resistant NSCLC. Interaction between miR-495-3p and circ_0030411 or CCND1 wasverified via luciferase reporterand RIP. Circ_0030411 and CCND1 were increased in DDP-resistant NSCLC tissues and cells, andmiR-495-3p level was decreased. Circ_0030411 knockdown hindered cell growth, migration, invasion, in DDP-resistant NSCLC cells, and improved DDP sensitivityof NSCLC in vivo. Mechanistically, circ_0030411 acted as a sponge of miR-495-3p to affect CCND1expression. Circ_0030411 facilitated DDP resistance by regulating the miR-495-3p/CCND1 axis, highlighting a promising target for NSCLC patients.

Knockdown of circLRWD1 weakens DDP resistance via reduction of SIRT5 expression through releasing miR-507 in non-small cell lung cancer.

Cisplatin (DDP) is an antineoplastic agent for non-small cell lung cancer (NSCLC). Hsa_circ_0081664 (circLRWD1) is overexpressed in DDP-resistant NSCLC cells, but its function is unclear. Thus, this study is to investigate whether circLRWD1 participates in DDP resistance in NSCLC. Changes in circLRWD1 expression were determined by real-time quantitative PCR. Effects of circLRWD1 inhibition on DDP-resistant NSCLC cell viability, proliferation, migration, invasion, and apoptosis were analyzed. The sponge function of circLRWD1 was predicted by bioinformatics analysis and verified by dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. The function of circLRWD1 in DDP resistance was verified by xenograft models. CircLRWD1 was unconventionally overexpressed in DDP-resistant NSCLC samples and cells. Moreover, circLRWD1 silencing decreased IC 50 value, restrained cell proliferation, reduced cell migration and invasion, and facilitated cell apoptosis in DDP-resistant NSCLC cells. Also, circLRWD1 knockdown elevated DDP-resistant NSCLC cell sensitivity to DDP in xenograft models. Furthermore, circLRWD1 regulated SIRT5 expression via adsorbing miR-507. SIRT5 overexpression weakened circLRWD1 silencing-mediated suppression of cell resistance to DDP in DDP-resistant NSCLC cells. In conclusion, circLRWD1 elevated SIRT5 expression via adsorbing miR-507, resulting in promoting NSCLC cell resistance to DDP, providing evidence to explain the significant role of circLRWD1 in DDP resistance in NSCLC.

The malignant property of circHIPK2 for angiogenesis and chemoresistance in non-small cell lung cancer

Chemotherapy resistance limits the efficacy of cisplatin (DDP) when treating non-small cell lung cancer (NSCLC). Circular RNAs (circRNAs) confers a regulatory role in drug resistance. Innovatively, the regulatory role of circular RNA HIPK2 (circHIPK2) in DDP resistance was probed in the work. In this research, tumor tissues and matched normal tissues were obtained from 52 NSCLC patients, and the expressions of circHIPK2, miR-1249–3p and VEGFA in the tissues were detected by qPCR or Western Blot. Correlation analysis of circHIPK2 expression with survival prognosis and clinicopathological features was conducted. Parental NSCLC cell lines (A549, H460) and DDP-resistant cell lines (A549/DDP, H460/DDP) were selected, and the expression of circHIPK2, miR-1249–3p and VEGFA in the cells were detected. Cell IC50 value, proliferation, migration, invasion, apoptosis and angiogenesis were detected. Tumor xenografts were established to detect the role of circHIPK2 in vivo. The binding relationship between circHIPK2, miR-1249–3p and VEGFA was verified by dual luciferase reporter experiment, RNA pull down and RIP experiment. Our data showed that circHIPK2 and VEGFA were abnormally overexpressed and miR-1249–3p was underexpressed in DDP-resistant NSCLC tissues and cell lines. CircHIPK2 knockdown or miR-1249–3p upregulation inhibited DDP resistance, malignant behavior, and angiogenesis in NSCLC. CircHIPK2 by competitive absorption of miR-1249–3p mediated VEGFA. CircHIPK2 promoted the sensitivity of drug-resistant cells to DDP in NSCLC by regulating VEGFA. CircHIPK2 enhanced the growth of DDP-resistant NSCLC cells in vivo. In conclusion, circHIPK2 has the malignant property for angiogenesis and chemoresistance in NSCLC via the network of miR-1249–3p/VEGFA.

Circular RNA hsa_circ_0068252 Functions in Cisplatin Resistance and Immune Response via miR-1304-5p/PD-L1 Axis in Non-Small Cell Lung Cancer

Background: Research suggests that circRNAs play important roles in non-small cell lung cancer (NSCLC). The function of hsa_circ_0068252 in NSCLC, especially in cisplatin (DDP) resistance and the mechanisms, was explored in this study. Methods: NSCLC patient samples and two NSCLC cell lines along with corresponding DDP-resistant cell lines were used. Expression levels of circ_0068252 were detected. SiRNA for circ_0068252 and inhibitor for miRNA were used in all functional analyses. A co-culture system of NSCLC cells with CD8+ T cells was used. The cellular location of circ_0068252 was detected and its target miRNA was predicted and verified. Finally, the mechanism responsible for circ_0068252 function on PD-L1 was analyzed using luciferase reporter assay in the two DDP-resistant cell lines, as well as in the co-culture system. The cytotoxicity of T cells was detected by lactate dehydrogenase assay. Results: Our findings revealed that a high level of circ_0068252 was correlated with poor prognosis of NSCLC and DDP resistance. Knockdown of circ_0068252 could promote the sensitivity of DDP-resistant NSCLC cells to DDP. Moreover, knockdown of circ_0068252 could regulate the immune microenvironment which was mediated via CD8+ T cells. Finally, circ_0068252 could up-regulate PD-L1 expression by adsorbing miR-1304-5p. Conclusion: The circ_0068252/miR-1304-5p/PD-L1 signal axis participates in the regulation of DDP resistance and immune escape of NSCLC cells. Our results suggest that circ_0068252 may be a potential diagnostic marker and therapeutic target for DDP-resistant NSCLC.

Exosome-transmitted circVMP1 facilitates the progression and cisplatin resistance of non-small cell lung cancer by targeting miR-524-5p-METTL3/SOX2 axis

Background Circular RNAs (circRNAs) play important regulatory roles in multiple human malignancies, including non-small cell lung cancer (NSCLC). Here, we explored the role of circRNA vacuole membrane protein 1 (circVMP1) in NSCLC progression and cisplatin (DDP) resistance. Methods The DDP resistance, proliferation, sphere formation ability, migration, invasion, and apoptosis of NSCLC cells were analyzed by Cell Counting Kit-8 (CCK8) assay, 5-ethynyl-2′-deoxyuridine (EdU) assay, sphere formation assay, wound healing assay, Transwell assay, and flow cytometry. Methylated RIP-qPCR (MeRIP-qPCR) was conducted to analyze the m6A modification level of SRY-box transcription factor 2 (SOX2). Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA-pull down assay were performed to confirm the intermolecular interaction. Exosomes were identified by transmission electron microscopy (TEM) and characterized by nanoparticle tracking analysis (NTA). Results CircVMP1 expression was markedly elevated in DDP-resistant NSCLC cell lines compared with their parental cell lines. CircVMP1 absence restrained the proliferation, sphere formation, migration, invasion, and DDP resistance and promoted the apoptosis of DDP-resistant NSCLC cells. CircVMP1 acted as microRNA-524-5p (miR-524-5p) sponge to up-regulate the expression of methyltransferase 3, N6-adenosine-methyltransferase complex catalytic subunit (METTL3) and SOX2. CircVMP1 silencing restrained the malignant behaviors and DDP resistance of A549/DDP and H1299/DDP cells by targeting miR-524-5p. Exosomal circVMP1 disseminated the malignant properties and DDP resistance to DDP-sensitive cells. Exosomal circVMP1 elevated the DDP resistance of xenograft tumors in vivo. Exosomal circVMP1 was up-regulated in the serum samples of DDP-resistant NSCLC patients compared with DDP-sensitive patients. Conclusion Exosome-mediated transmission of circVMP1 promoted NSCLC progression and DDP resistance by targeting miR-524-5p-METTL3/SOX2 axis. Highlights CircVMP1 level is up-regulated in DDP-resistant NSCLC cell lines compared with DDP-sensitive cell lines. CircVMP1 absence restrains the malignant behaviors and DDP resistance of A549/DDP and H1299/DDP cells. CircVMP1-miR-524-5p/METTL3/SOX2 axis is identified for the first time. CircVMP1 plays an oncogenic role by targeting miR-524-5p-METTL3/SOX2 axis in A549/DDP and H1299/DDP cells. Exosomal circVMP1 transmits the malignant properties and DDP resistance to DDP-sensitive cells.

Circ_0030998 Restrains Cisplatin Resistance Through Mediating miR-1323/PDCD4 Axis in Non-small Cell Lung Cancer.

We aimed to explore the underlying mechanism behind the cisplatin (DDP) resistance of non-small cell lung cancer (NSCLC) cells to identify novel potential therapeutic targets to overcome chemoresistance. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were applied to analyze RNA and protein expression, respectively. Cell Counting Kit-8 (CCK8) assay was conducted to analyze the DDP resistance of NSCLC cells. Colony formation assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay were performed to analyze cell proliferation ability. Flow cytometry was applied to assess cell apoptosis. Cell migration and invasion were assessed by transwell assays. Cell glycolytic metabolism was analyzed using commercial kits. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to test the intermolecular target relations. Circular RNA_0030998 (circ_0030998) was down-regulated in DDP-resistant NSCLC tissues and cell lines. Circ_0030998 overexpression restrained the DDP resistance, proliferation, migration, invasion and glycolytic metabolism and triggered the apoptosis of NSCLC cells. Circ_0030998 overexpression contributed to the anti-tumor effect of DDP in the growth of xenograft tumor in vivo. MicroRNA-1323 (miR-1323) was a molecular target of circ_0030998 in NSCLC cells. Circ_0030998 overexpression-mediated effects on the DDP resistance and malignant properties of NSCLC cells were largely based on its negative regulation of miR-1323. MiR-1323 interacted with programmed cell death 4 (PDCD4). Circ_0030998 positively regulated PDCD4 expression partly through sponging miR-1323. MiR-1323 silencing restrained DDP resistance and progression of NSCLC partly through up-regulating PDCD4. Circ_0030998 suppressed DDP resistance and NSCLC progression depending on the regulation of miR-1323/PDCD4 axis.

Hsa_circ_0017639 regulates cisplatin resistance and tumor growth via acting as a miR-1296-5p molecular sponge and modulating sine oculis homeobox 1 expression in non-small cell lung cancer

ABSTRACT Cisplatin (DDP)-induced chemoresistance is an important reason for the failure of non-small cell lung cancer (NSCLC) treatment. Circular RNAs (circRNAs) participate in the chemoresistance of diverse cancers. However, the function of hsa_circ_0017639 (circ_0017639) in the DDP resistance of NSCLC is unclear. Forty-one NSCLC samples (21 DDP-resistant samples and 20 DDP-sensitive samples) were utilized in the research. The relative expression levels of some genes were determined by real-time quantitative polymerase chain reaction (RT-qPCR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay for half-maximal inhibitory concentration (IC50) value of DDP and cell viability, colony formation and 5-ethynyl-2’-deoxyuridine (EDU) assays for cell proliferation, flow cytometry assay for cell apoptosis, transwell assay for cell invasion and wound-healing assay for cell migration were performed. The regulation mechanism of circ_0017639 was demonstrated by a dual-luciferase reporter assay. We observed higher levels of circ_0017639 in DDP-resistant NSCLC samples and cells. Functionally, circ_0017639 silencing decreased tumor growth and elevated DDP sensitivity in vivo and induced apoptosis, repressed proliferation, invasion, and migration of DDP-resistant NSCLC cells in vitro. Mechanically, circ_0017639 modulated sine oculis homeobox 1 (SIX1) expression via sponging microRNA (miR)-1296-5p. Also, miR-1296-5p inhibitor restored circ_0017639 knockdown-mediated impacts on cell DDP resistance in DDP-resistant NSCLCs. Furthermore, SIX1 overexpression counteracted the inhibiting impact of miR-1296-5p upregulation on DDP resistance and malignant phenotypes of DDP-resistant NSCLC cells. In conclusion, circ_0017639 conferred DDP resistance and promoted tumor growth via elevating SIX1 expression through sequestering miR-1296-5p in NSCLC, providing a new mechanism for understanding the chemoresistance and progression of NSCLC.

Circ_0004015 silencing represses cisplatin chemoresistance and tumor progression by reducing KLF8 in a miR-198-dependent manner in non-small cell lung cancer.

Circular RNA (circRNA) plays vital roles in diverse cancer progression, including non-small cell lung cancer (NSCLC). Herein, the role of circ_0004015 in regulating the sensitivity of NSCLC to cisplatin (DDP) is revealed. The RNA expression of circ_0004015, microRNA-198 (miR-198) and kruppel like factor 8 (KLF8) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. The half maximal inhibitory concentration of DDP and cell proliferation were determined by cell counting kit-8 assay. Cell colony formation ability, migration, invasion and apoptosis were investigated by colony-forming assay, transwell assay and flow cytometry analysis, respectively. The effect of circ_0004015 knockdown on DDP sensitivity in vivo was demonstrated by mouse model assay. The interactions among circ_0004015, miR-198 and KLF8 were predicted by bioinformatics methods, and identified by mechanism assays. The expression of circ_0004015 and KLF8 was apparently upregulated, while miR-198 expression was downregulated in DDP-resistant NSCLC tissues and cells compared with control groups. Additionally, circ_0004015 silencing repressed DDP resistance, cell proliferation, migration and invasion, but induced cell apoptosis in DDP-resistant NSCLC cells. Circ_0004015 knockdown promoted the effect of DDP on tumor formation in vivo. Also, miR-198 inhibitors attenuated circ_0004015 depletion-mediated action though associating with circ_0004015. MiR-198 regulated DDP sensitivity and NSCLC progression by targeting KLF8. Furthermore, circ_0004015 modulated KLF8 expression through interaction with miR-198. Circ_0004015 conferred DDP resistance and promoted NSCLC progression by miR-198/KLF8 pathway, proving a potential target for studying DDP-mediated treatment of NSCLC.

Circ_0020123 enhances the cisplatin resistance in non-small cell lung cancer cells partly by sponging miR-140-3p to regulate homeobox B5 (HOXB5)

ABSTRACT Cisplatin (DDP) therapy is widely used for the treatment of non-small cell lung cancer (NSCLC), but the curative effect is limited by chemoresistance. This study was designed to explore circ_0020123 function in DDP resistance of NSCLCDDP. Expression detection for circ_0020123, microRNA-140-3p (miR-140-3p) and homeobox B5 (HOXB5) was performed by real-time polymerase chain reaction (qRT-PCR). Half inhibitory concentration (IC50) of DDP and cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay. Colony formation ability was assessed using colony formation assay. Cell migration and invasion were evaluated via transwell assay. Cell apoptosis was examined by flow cytometry. Protein analysis was conducted by Western blot. Dual-luciferase reporter assay was used to affirm target interaction. Circ_0020123 expression was upregulated in DDP-resistant NSCLC cells. DDP resistance was reduced by downregulation of circ_0020123 in NSCLC cells. Circ_0020123 was identified as a miR-140-3p sponge. The effect of si-circ_0020123 on DDP resistance was partly associated with miR-140-3p upregulation. HOXB5 was a downstream target for miR-140-3p. Overexpression of HOXB5 mitigated miR-140-3p-induced inhibition of DDP resistance in NSCLC cells. Circ_0020123 upregulated the level of HOXB5 partly via sponging miR-140-3p. Also, circ_0020123 promoted tumor growth in NSCLC/DDP xenografts by regulating miR-140-3p and HOXB5 levels at least in part. These results revealed that circ_0020123 promoted DDP resistance in NSCLC cells partly by targeting miR-140-3p/HOXB5 axis, indicating that circ_0020123 might be used as a molecular target in DDP treatment for NSCLC.

Knockdown of LINC00511 decreased cisplatin resistance in non-small cell lung cancer by elevating miR-625 level to suppress the expression of leucine rich repeat containing eight volume-regulated anion channel subunit E.

LINC00511 has been reported as a biomarker related to the prognosis of non-small cell lung cancer (NSCLC), but the molecular mechanism and exact functions of LINC00511 in chemoresistance of NSCLC remain to be elucidated. RT-qPCR was used to evaluate the mRNA expression of LINC00511, miR-625, and leucine rich repeat containing 8 volume-regulated anion channel subunit E (LRRC8E). Western blotting detected the protein levels of Ki-67, MMP-9, cleaved-caspase-3. The interaction between miR-625 and LINC00511 or LRRC8E was verified by luciferase reporter assays. CCK-8, TUNEL, and Transwell assays were used to evaluate IC50 value, proliferation, migration, and invasion of NSCLC cells. In our study, it was discovered that the levels of LINC00511 and LRRC8E were increased, while miR-625 expression was decreased in NSCLC tissues, DDP-resistant NSCLC cells, and non-resistant NSCLC cells. LINC00511 depletion significantly curbed cell growth, IC50 value, and metastasis in DDP-resistant NSCLC cells. In addition, the influence of LINC00511 deficiency on the DDP resistance in NSCLC was overturned by suppressing miR-625. Furthermore, LRRC8E overexpression abolished the promotive effect of miR-625 abundance on the DDP sensitivity in DDP-resistant NSCLC cells. Our results demonstrated that LINC00511 increased DDP resistance in NSCLC by suppressing miR-625 to upregulate LRRC8E.

Arteannuin B Enhances the Effectiveness of Cisplatin in Non-Small Cell Lung Cancer by Regulating Connexin 43 and MAPK Pathway.

Cisplatin (DDP)-based chemotherapy is the first-line regimen for advanced non-small cell lung cancer (NSCLC) patients. However, advanced NSCLC patients may have innate resistance to DDP or develop resistance during DDP treatment. We investigated a natural compound, arteannuin B (Art B), for its potential effects on DDP resistance in NSCLC. Art B was isolated from Artemisia annua by chromatographic purification and spectral elucidation. The activities of Art B on DDP-mediated effects were examined using in vitro and in vivo assays. We observed significant correlations in T stage, clinical stage, chemotherapy resistance and poor survival of NSCLC patients with low Cx43 expression. Art B enhanced the effectiveness of cisplatin by increasing Cx43 expression in normal and DDP-resistant NSCLC cells. Art B also increased DDP uptake through up-regulating Cx43. The combination of DDP and Art B showed better therapeutic effect than individual treatments both in vitro and in vivo. Art B increased intracellular Fe[Formula: see text] level, promoted calcium influx, and activated gap junction and MAPK pathways, which might contribute to Art B-mediated effects. Art B may serve as a new drug candidate to enhance the antitumor effect of DDP on NSCLC.

CircHUWE1 Exerts an Oncogenic Role in Inducing DDP-Resistant NSCLC Progression Depending on the Regulation of miR-34a-5p/TNFAIP8.

Background Circular RNAs (circRNAs) are reported as competing endogenous RNAs (ceRNAs) and play key roles in non-small-cell lung cancer (NSCLC) progression. Thus, this study was aimed at clarifying underlying molecular mechanisms of circHUWE1 in NSCLC. Methods The quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analyses were used for examining circHUWE1, microRNA-34a-5p (miR-34a-5p), and tumor necrosis factor alpha-induced protein 8 (TNFAIP8). IC50 of cisplatin (DDP) in A549/DDP and H1299/DDP cells and cell viability were analyzed by the Cell Counting Kit 8 (CCK-8) assay. Colony forming assay was performed to assess colony forming ability. Cell apoptosis and cell cycle distribution were determined by flow cytometry. Migrated and invaded cell numbers were examined by transwell assay. The association among circHUWE1, miR-34a-5p, and TNFAIP8 was analyzed by dual-luciferase reporter and RNA immunoprecipitation assays. A xenograft experiment was applied to clarify the functional role of circHUWE1 in vivo. Results circHUWE1 was upregulated in NSCLC tissues and cells, especially in DDP-resistant groups. circHUWE1 downregulation inhibited DDP resistance, proliferation, migration, and invasion while it induced apoptosis and cell cycle arrest of DDP-resistant NSCLC cells, which was overturned by silencing of miR-34a-5p. TNFAIP8 was a functional gene of miR-34a-5p, and the suppressive effects of miR-34a-5p overexpression on DDP-resistant NSCLC progression were dependent on the suppression of TNFAIP8. circHUWE1 inhibition also delayed tumor growth of DDP-resistant NSCLC cells. Conclusion circHUWE1 functioned as a promoter in DDP-resistant NSCLC by interaction with miR-34a-5p-TNFAIP8 networks, providing novel insight into DDP-resistant NSCLC diagnosis and treatment.