Behaviors Of Lung Adenocarcinoma Cells Research Articles

Circ_0004140 promotes lung adenocarcinoma progression by upregulating NOVA2 via sponging miR-330-5p.

Circular RNAs (circRNAs) play a significant role in the tumorigenesis and progression of diverse human cancers, including lung adenocarcinoma. A previous study suggested that circ_0004140 expression was increased in lung adenocarcinoma cells. However, the molecular mechanism of circRNA circ_0004140 involved in lung adenocarcinoma is poorly defined. Circ_0004140, microRNA-330-5p (miR-330-5p), and NOVA alternative splicing regulator 2 (NOVA2) expression were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, migration, invasion, and angiogenesis ability were assessed using 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, transwell, and capillary-like network formation assays. Proliferating cell nuclear antigen (PCNA), cyclin D1, and NOVA2 protein levels were detected using Western blot assay. The interaction between miR-330-5p and circ_0004140 or NOVA2 was verified by dual-luciferase reporter assay. Xenograft tumor model was utilized to assess the role of circ_0004140 in tumor growth in vivo. Circ_0004140 was upregulated in lung adenocarcinoma tissues and cell lines. Circ_0004140 silencing suppressed cell proliferation, migration, invasion and tube formation ability, and triggered the apoptosis of lung adenocarcinoma cells. Circ_0004140 acted as a molecular sponge for miR-330-5p, and miR-330-5p silencing largely reversed circ_0004140 knockdown-induced effects in lung adenocarcinoma cells. NOVA2 was a target of miR-330-5p, and NOVA2 overexpression might largely overturn miR-330-5p overexpression-induced influences in lung adenocarcinoma cells. Circ_0004140 upregulated NOVA2 expression via sponging miR-330-5p in lung adenocarcinoma cells. Circ_0004140 silencing restrained xenograft tumor growth in vivo. Circ_0004140 knockdown might suppress the malignant biological behaviors of lung adenocarcinoma cells via miR-330-5p-dependent regulation of NOVA2.

Retracted: Calycosin Inhibits the Malignant Behaviors of Lung Adenocarcinoma Cells by Regulating the circ_0001946/miR-21/GPD1L/HIF-1α Signaling Axis.

[This retracts the article DOI: 10.1155/2022/3969389.].

Targeting the Phosphatidylinositol 3-Kinase/AKT1 Signaling Pathway: Iphigenia indica Extracts Induce Apoptosis in Lung Adenocarcinoma Cells

This study aimed to investigate the inhibitory effects of Iphigenia indica extracts on lung adenocarcinoma A549 cells through the PI3K/AKT1 signaling pathway. The researchers treated A549 cells with different concentrations of Iphigenia indica extracts and conducted various assays. The results showed that the viability of A549 cells decreased with increasing concentration of Iphigenia indica extracts. Iphigenia indica extracts and PI3K/AKT inhibitor had a higher inhibitory rate of cell proliferation and colony formation, reduced migration and invasion, and induced apoptosis in A549 cells compared to the control group. Furthermore, Iphigenia indica extracts and PI3K/AKT inhibitor reduced the protein levels of Bcl-2, PI3K, and AKT1 and increased the level of Bax. The findings suggest that Iphigenia indica extracts may inhibit malignant biological behaviors of lung adenocarcinoma cells through the PI3K/AKT1 signaling pathway by inducing apoptosis, inhibiting proliferation, migration and invasion, and regulating the expression of Bcl-2, Bax, PI3K, and AKT1. Overall, Iphigenia indica extracts may have potential as a therapeutic agent for lung adenocarcinoma.

Galectin-1 knockdown inhibits proliferation, migration, invasion and promotes apoptosis of lung adenocarcinoma cells in vitro

To investigate the effect of galectin-1 on biological behaviors of lung adenocarcinoma cells and the underlying mechanism. The expression levels of galectin-1 mRNA were detected in 8 pairs of lung adenocarcinoma tissues and adjacent normal tissues and in lung adenocarcinoma cell lines A549 and H1299 and normal bronchial epithelial cell line BEAS-2b using qRT-PCR. The effect of galectin-1 knockdown by RNA interference on the proliferation, invasion and migration abilities and apoptosis of lung adenocarcinoma cells were examined using CCK8 assay, Transwell assay, scratch assay and flow cytometry. Western blotting was performed to detect the expressions of apoptosis-related proteins BAX, BCL-2, and caspase-3 and the proteins involved in the AKT and ERK pathways. The mRNA expression of galectin-1 was significantly increased in lung cancer tissues and lung adenocarcinoma cell lines (P < 0.05). In lung adenocarcinoma cells, galectin-1 knockdown significantly inhibited cell proliferation, migration and invasion and obviously increased cell apoptosis rate (P < 0.05), causing also significant reduction of the phosphorylation level of ERK signaling pathway (P < 0.05). Galectin-1 knockdown inhibits proliferation, migration, and invasion and promotes apoptosis of lung adenocarcinoma cells, and this effect is mediated probably by inhibition of the phosphorylation levels of the ERK pathway.

ID2 inhibits lung adenocarcinoma cell malignant behaviors by inhibiting the activation of the PI3K/AKT/mTOR signaling pathway

Lung cancer is the most common cancer and one of the main causes of cancer-related deaths, presenting in most cases as metastatic disease. Given the frequent gene mutation and/or signaling deregulation in lung adenocarcinoma, identifying novel factors or agents that target these signaling pathways may be promising strategies for lung adenocarcinoma therapy. Herein, we identified inhibitor of DNA binding 2 (ID2) as an aberrantly downregulated gene in lung adenocarcinoma. ID2 overexpression not only suppressed the viability, colony formation ability, and migration ability of lung adenocarcinoma cells but also decreased the protein levels of N-cadherin, MMP2, MMP9 and the phosphorylation levels of AKT and mTOR. The effects of PI3K/AKT/mTOR signaling agonist on lung adenocarcinoma cells were opposite to those of ID2 overexpression, partially reversing the effects of ID2 overexpression. In these experimental tissue samples, ID2 protein levels and mRNA expression were also down-regulated compared with those in adjacent non-cancerous tissues. Altogether, these findings indicated that ID2 exerts its tumor-suppressive effects on the malignant behavior of lung adenocarcinoma cells by inhibiting the activation of the PI3K/AKT/mTOR signaling pathway. Restoration of ID2 expression in lung adenocarcinoma cells may improve the therapeutic efficacy of lung adenocarcinoma therapies.

Calycosin Inhibits the Malignant Behaviors of Lung Adenocarcinoma Cells by Regulating the circ_0001946/miR-21/GPD1L/HIF-1α Signaling Axis.

Objective To clarify the potential function and molecular mechanism of calycosin in lung adenocarcinoma (LUAD) cells. Methods LUAD cells (A549 and H1299) were treated with calycosin at different concentrations (25 nM, 50 nM, and 100 nM) for 24 h. The colony formation, invasion, and migration of the cells were assessed by colony formation, transwell, and scratch assays, respectively. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to determine the mRNA expression level of circ_0001946, miR-21, glycerol-3-phosphate dehydrogenase 1 like (GPD1L), and hypoxia-inducible factor-1α (HIF-1α) in clinical tissue samples and LUAD cells. RNA pull-down assay and dual-luciferase reporter assay were performed to verify the relationship among circ_0001946, miR-21, GPD1L, and HIF-1α. Western blot was performed to detect the protein expression of epithelial-mesenchymal transition (EMT) process-related genes (E-cadherin, N-cadherin, and snail) and GPD1L as well as HIF-1α. Results Calycosin inhibited colony formation, invasion, migration, and EMT progression in A549 and H1299 cells. Besides, calycosin was able to regulate the expression of circ_0001946, miR-21, GPD1L, and HIF-1α in LUAD cells. According to the findings of QRT-PCR, the expression level of circ_0001946 and GPD1L in LUAD tissues was significantly lower than that in adjacent noncancerous normal tissues, and the expression of miR-21 and HIF-1α was also significantly increased in clinical tissue samples. In addition, there was a targeted regulatory relationship among the above four expressions. Knockdown of circ_0001946 expression in A549 cells treated with calycosin enhanced the malignant behavior of A549 cells and inhibited the anticancer effect of calycosin. However, the knockdown of miR-21 promoted the anticancer effect of calycosin and inhibited the malignant behavior of A549. Conclusion Calycosin can inhibit colony formation, invasion, migration, and EMT process of LUAD cells via regulating the circ_0001946/miR-21/GPD1L/HIF-1α signaling axis and could be a promising therapeutic drug for LUAD.

Origin recognition complex subunit 1 (ORC1) augments malignant behaviors of lung adenocarcinoma cells via targeting Wnt signaling

ABSTRACT It has been reported that origin recognition complex subunit 1 (ORC1) plays an oncogenic role in certain human cancers. Nevertheless, its regulatory function in lung adenocarcinoma (LUAD) progression was poorly understood. In this study, gene and protein levels were measured via RT-qPCR and Western blotting. LUAD cell viability, apoptosis, and metastasis were determined via CCK-8, TUNEL, and Transwell assays. Bioinformatics analyses were performed using Genotype Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) databases. Herein, it was revealed that ORC1 was evidently upregulated and positively correlated to unsatisfactory prognosis in LUAD. Besides, single-sample gene set enrichment analysis (ssGSEA) revealed that ORC1 is negatively associated with 17 immune infiltrating cells and differently expressed in several kinds of immune cells. Also, Gene Ontology (GO) analysis indicated the involvement of ORC1 in several molecular functions. In addition, in vitro experiments demonstrated that ORC1 facilitated malignant behaviors of LUAD cells; moreover, animal assays further affirmed that ORC1 promoted LUAD tumor growth in vivo. As for the molecular mechanisms involved, it was found that ORC1 depletion inhibited the Wnt pathway in LUAD cells. Furthermore, rescue experiments demonstrated that Wnt signaling activation could abate the impacts of ORC1 knockdown on tumorigenic phenotypes of LUAD cells. In conclusion, our findings demonstrated that ORC1 promoted LUAD progression by regulating the Wnt signaling, indicating ORC1 could be an auspicious biomarker or target for LUAD diagnosis and treatment.

Ropivacaine Inhibits Lung Cancer Cell Malignancy Through Downregulation of Cellular Signaling Including HIF-1α In Vitro.

Background: Ropivacaine is widely used to induce regional anesthesia during lung cancer surgery. Previous studies reported that amide-linked local anesthetics, e.g., ropivacaine, affected the biological behavior of lung adenocarcinoma cells, but the conclusion is controversial and warrants further study. This study set out to investigate the biological effects of ropivacaine on cultured lung cancer cells and underlying mechanisms. Methods: Lung cancer cell lines (A549 and H1299) were cultured and then treated with or without ropivacaine (0.5, 1, and 2 mM) for 48 or 72 h. Their proliferation, migration, and invasion together with cell death and molecules including hypoxia inducible factor (HIF)-1α, VEGF, matrix metalloproteinase (MMP)-1, MMP-2, and MMP-9 expression associated with these changes were determined. Results: Ropivacaine significantly inhibited proliferation and migration, invasion, and cell death in a concentration-dependent manner in both cell lines. Ropivacaine also promoted cell death and induced a concentration- and time-dependent cell arrest towards the G0/G1 phase. Expression of VEGF, MMP-1, MMP-2, MMP-9, and HIF-1α in both cell lines was also inhibited by ropivacaine in a concentration-related manner. Conclusion: Our data indicated that ropivacaine inhibited lung cancer cell malignancy, which may be associated with downregulation of cell-survival-associated cellular molecules. The translational value of the current work is subjected to further study.

Hsa_circ_0020850 promotes the malignant behaviors of lung adenocarcinoma by regulating miR-326/BECN1 axis

BackgroundCircular RNAs (circRNAs) are a novel type of endogenous RNAs and play vital roles in lung adenocarcinoma. However, the function and underlying mechanism of circ_0020850 in lung adenocarcinoma remain unknown.MethodsThe levels of circ_0020850, microRNA-326 (miR-326), and Beclin1 (BECN1) were analyzed by real-time quantitative polymerase chain reaction and western blot analyses. The migration and invasion were determined by wound healing and transwell assays, respectively. Colony formation assay was used to assess cell proliferation ability. The angiogenic ability was analyzed by Matrigel angiogenesis assay. The apoptosis rate was calculated by flow cytometry assay. Dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays were conducted to confirm the interaction relationship among circ_0020850, miR-326, and BECN1. A xenograft mice model was established to assess the role of circ_0020850 in vivo.ResultsWe found that circ_0020850 was obviously overexpressed in lung adenocarcinoma tissues and cells. Knockdown of circ_0020850 inhibited migration, invasion, proliferation, and angiogenesis but induced apoptosis in lung adenocarcinoma cells in vitro, as well as curbed tumor growth in vivo. MiR-326 was a target of circ_0020850, and knockdown of miR-326 abolished the suppression effect of circ_0020850 on the malignant behaviors of lung adenocarcinoma cells. Additionally, miR-326 could negatively regulate BECN1 expression, thereby regulating lung adenocarcinoma cell phenotypes. Importantly, circ_0020850 could directly bind to miR-326 and thus relieve miR-326-mediated inhibition on BECN1.ConclusionCirc_0020850 promoted the malignant development of lung adenocarcinoma by regulating miR-326/BECN1 axis, indicating that circ_0020850 might serve as a promising target for the diagnosis and treatment of lung adenocarcinoma patients.

Effect of Mir-299-3p on the biological function of lung adenocarcinoma cell H1299 through targeting PTPRD

The paper aimed to investigate the effects of up-regulation and down-regulation of Mir-299-3p on the proliferation, migration, invasion and apoptosis of lung adenocarcinoma cell line H1299, and to preliminarily explore the mechanism of Mir-299-3p regulating the biological behavior of lung adenocarcinoma cells. Mir-299-3p inhibitor and Mir-299-3p mimics were transfected into lung adenocarcinoma cell line H1299, and the transfection efficiency was measured by fluorescence microscopy. The successfully transfected lung adenocarcinoma cells were detected of proliferation, migration, invasion, and apoptosis. Mir-299-3p inhibitor and Mir-299-3p mimics were used to down-regulate and up-regulate Mir-299-3p respectively. Western blot was employed to detect the expressions of STAT3, p-STAT3, caspase3, Bcl-2, Bax and MMP-9 proteins in lung adenocarcinoma cells. Small interfering RNA technology was applied to construct a cell line with low expression of PTPRD. WB was used to measure the transfection efficiency to determine whether the down-regulation of PTPRD can partially or completely reverse the proliferation, migration, invasion, and apoptosis of lung adenocarcinoma cells after the down-regulation of Mir-299-3p. It was also determined whether the down-regulation of PTPRD can partially or completely reverse the effect of Mir-299-3p down-regulation on the expressions of p-STAT3, MMP-9, Cleaved-caspase3, Bcl-2 and Bax proteins in lung adenocarcinoma cells. Down-regulation of Mir-299-3p can inhibit the proliferation and invasion of lung adenocarcinoma cell H1299, promote cell apoptosis, inhibit the expression of p-STAT3 and MMP-9, promote the expressions of apoptosis-inducing proteins such as Bax and Cleaved-caspase3, and also inhibit the expression of apoptosis inhibitor protein Bcl-2. The up-regulation of Mir-299-3p worked in the opposite way. PTPRD is the direct target gene of Mir-299-3p. Mir-299-3p may directly target PTPRD to regulate the expressions of p-STAT3, MMP-9, Cleaved-caspase3, Bcl-2 and Bax proteins to affect the biological behavior of lung adenocarcinoma cells.

TRIM55 suppresses malignant biological behavior of lung adenocarcinoma cells by increasing protein degradation of Snail1

ABSTRACT Up until now, cancer refractoriness and distal organ metastatic disease remain as major obstacles for oncologists to achieve satisfactory therapeutic effects for lung adenocarcinoma patients. Previous studies indicated that TRIM55, which participates in the natural development of muscle and cardiovascular system, plays a protective role in hepatocellular carcinoma (HCC) pathogenesis. Therefore, in this study, we aimed to unveil the detailed molecular mechanism of TRIM55 and identify the potential target for lung adenocarcinoma patients. Surgical samples and lung cancer cell lines were collected to detect the TRIM55 expression for patients with or without lymph node/distal organ metastasis. Cellular functional assays including transwell assay, wound healing assay, cellular survivability assay, etc. as well as ubiquitination assay were performed to evaluate the impact of TRIM55/Snail1 regulatory network via the UPP pathway on lung cancer tumor cell migration and chemo-resistance. Lung cancer tissues and tumor cell lines exhibited significantly lower levels of TRIM55 expression. Functional study further indicated that TRIM55 inhibited chemo-resistance, migration, and cancer stem-cell like phenotype of tumor cells. Further detailed molecular experiments indicated that TRIM55 promoted degradation of Snail1 via the UPP pathway, which played an interesting role in the regulation of cancer cell malignancy. This study provided novel theory that TRIM55 acted as a potential tumor suppressor by inhibition of tumor cell malignancy through enhancement of Snail1 degradation via the UPP pathway. Our research will inspire further exploration on TRIM55 to promote therapeutic effects for lung adenocarcinoma patients.

ETV4 mediated lncRNA C2CD4D-AS1 overexpression contributes to the malignant phenotype of lung adenocarcinoma cells via miR-3681-3p/NEK2 axis

ABSTRACT Lung adenocarcinoma (LUAD) is originated from the mucus-producing glands of the lungs. The involvement of long noncoding RNAs (lncRNAs) has been discovered in multiple diseases. In the present research, we aimed to unmask the role of C2CD4D and THEM5 antisense RNA 1 (C2CD4D-AS1) in LUAD. RT-qPCR or western blot analysis was respectively applied in the detection of RNA or protein expressions. The function of C2CD4D-AS1 in LUAD was assessed by functional assays. Through ChIP, RNA pull down, DNA pull down, RIP and luciferase reporter assays, the in-depth regulatory mechanism of C2CD4D-AS1 in LUAD was explored. C2CD4D-AS1 was dramatically overexpressed in LUAD tissues and cell lines. As a result, depletion of C2CD4D-AS1 significantly repressed cell proliferation, migration, invasion and stimulated cell apoptosis in LUAD. Mechanistically, ETS variant transcription factor 4 (ETV4) activated the transcription of C2CD4D-AS1 and stimulated its up-regulation in LUAD cells, thus affecting LUAD cell biological functions. Furthermore, C2CD4D-AS1 sponged microRNA-3681-3p (miR-3681-3p) and regulated NIMA-related kinase 2 (NEK2), thus participating in modulating LUAD cell biological behaviors. To conclude, C2CD4D-AS1 up-regulation induced by ETV4 enhanced NEK2 expression by sequestering miR-3681-3p to contribute to the malignant behaviors of LUAD cells.

The miR-4306/IGF2R axis modulates the lung adenocarcinoma response to irradiation in vitro and in vivo.

BackgroundLung adenocarcinoma accounts for more than 50% of non-small cell lung cancers. Dysregulated microRNAs (miRNAs) and coding genes play a critical role in lung adenocarcinoma irradiation resistance and might be promising therapeutic targets. In the present study, we demonstrate the effect of the miR-4306/IGF2R axis on malignant behaviors of lung adenocarcinoma cells and the response to irradiation.MethodsQuantitative realtime-PCR and Western blot assays were applied for miR-4306 and IGF2R expression in tumors and cells. A CCK-8 assay kit was used to detect cell viability. Colony formation assay was implied to detect cell proliferation. Transwell assay was used to detect cell invasion. A subcutaneous tumor model was performed in nude mice to detect tumor formation in vivo. Hematoxylin & eosin (H&E) staining were used to observe pathological status of tumor in nude mice. To validate the miR-4306 binding IGF2R 3'-UTR, a dual-luciferase reporter assay was performed.ResultsThe expression level of miR-4306 was dramatically upregulated in lung adenocarcinoma samples and cells, and could be induced by irradiation in a dose-dependent manner. In lung adenocarcinoma cells, miR-4306 overexpression significantly promoted cell viability and invasive abilities and attenuated the inhibitory effect of irradiation on malignant cancer cell behaviors. In a subcutaneous tumor model in nude mice, miR-4306 overexpression promoted tumor growth and attenuated the suppressive effect of irradiation on tumor growth. miR-4306 directly inhibited the expression of IGF2R. In lung adenocarcinoma cells without irradiation, IGF2R overexpression was inhibited, while IGF2R knockdown promoted cell viability and invasive abilities. The effects of miR-4306 overexpression were partially attenuated by IGF2R overexpression. In lung adenocarcinoma cells, suppressive role of irradiation on cancer cell viability and invasive abilities were enhanced by IGF2R overexpression, but attenuated by IGF2R knockdown. The effects of miR-4306 overexpression on cancer cell viability and invasive abilities were also partially attenuated by IGF2R overexpression in lung adenocarcinoma cells with irradiation. In tissue samples, expression of miR-4306 and IGF2R were negatively correlated.ConclusionsThe miR-4306/IGF2R axis could significantly affect lung adenocarcinoma progression and response to radiotherapy, and further investigation of the clinical implications of this axis is strongly recommended.

RETRACTED ARTICLE: Long non-coding RNA GATA6-AS1 upregulates GATA6 to regulate the biological behaviors of lung adenocarcinoma cells

BackgroundLung adenocarcinoma (LUAD) is known to be one of the leading causes of cancer-related deaths globally. In recent decades, long non-coding RNAs (lncRNAs) have been indicated to exert pivotal regulating functions in multiple biological behaviors in the initiation and development of LUAD. However, the functional mechanism of lncRNA GATA binding protein 6 antisense RNA 1 (GATA6-AS1) in LUAD has not been explored.MethodsIn the current study, GATA6-AS1 expression in LUAD tissues was revealed. Meanwhile, GATA6-AS1 expression in LUAD cells was investigated via RT-qPCR analysis. After A549 and H1975 cells were transfected with GATA6-AS1 overexpression plasmids, EdU and colony formation assays, TUNEL assays and flow cytometry analyses, as well as wound healing and Transwell assays were conducted to detect cell proliferation, apoptosis, migration and invasion. Afterwards, bioinformatic tools, western blot analyses, dual-luciferase reporter assays, and RNA immunoprecipitation (RIP) assays were performed to investigate the correlation of microRNA-4530 (miR-4530), GATA6-AS1 and GATA6.ResultsWe found that GATA6-AS1 expression was low-expressed in LUAD tissues and cells. Furthermore, the upregulation of GATA6-AS1 suppressed the proliferative, migration and invasion abilities, as well as promoted apoptotic rate of A549 and H1975 cells. Moreover, the mechanistic investigations revealed that GATA6-AS1 upregulated the expression of its cognate sense gene GATA6 by binding with miR-4530, thereby modulating the malignant progression of LUAD cells.ConclusionsGATA6-AS1 repressed LUAD cell proliferation, migration and invasion, and promoted cell apoptosis via regulation of the miR-4530/GATA6 axis, indicating GATA6-AS1 as a new prognostic biomarker for LUAD.

Influence of Autophagy Inhibition on Lung Adenocarcinoma Cell Migration and Invasion Ability, and Efficacy of Gefitinib.

An increasing number of studies have emphasized the role of autophagy in cancer cell metastasis and treatment of malignant tumors. Autophagy inhibitors have been widely used in combination therapies to treat advanced malignancies. Several lung adenocarcinoma cells harbor epidermal growth factor receptor (EGFR) gene mutations, and EGFR tyrosine kinase inhibitors (TKIs) are routinely used in the treatment of lung adenocarcinoma. However, a number of lung adenocarcinoma tumors do not respond or develop resistance to EGFR TKIs. The aim of the present study was to explore the effect of autophagy inhibition on the biological behavior of lung adenocarcinoma cells. In addition, whether autophagy inhibition increases the efficacy of gefitinib in lung adenocarcinoma was investigated. The activation of autophagy was inhibited via the reduction of the expression of ATG5 in A549, H1975 and HCC827 cells. ATG5 knockdown using ATG5 siRNA partially suppressed the LC3B-II expression, decreased the LC3B-I/II conversion rate and enhanced the P62 expression. Cell scratch test and Transwell assay showed that the inhibition of autophagy could impair the migration and invasion ability of cells. These studies suggested that autophagy may play a pro-survival role in lung adenocarcinoma.

Potassium voltage-gated channel subfamily D member 2 induces an aggressive phenotype in lung adenocarcinoma.

The study aimed to investigate the roles of potassium voltage-gated channel subfamily D member 2 (KCND2) in lung adenocarcinoma (AD). RNA sequencing data from The Cancer Genome Atlas (TCGA) database showed that the expression of KCND2 was elevated in lung AD samples compared to the normal samples, and its upregulation was significantly associated with the unfavorable clinic outcome of lung AD patients. Cell proliferation and transwell assays revealed that the growth, migration, and invasion of lung AD cells, which was crucial to cancer aggressiveness, were markedly inhibited after the depletion of KCND2. Importantly, we demonstrated that the depletion of KCND2 suppressed the biological behaviors of lung AD cells via restraining the expression of four tumor-related genes including PCNA, CDH2, SNAI1, and MMP2. Overall, KCND2 promotes the aggressiveness of lung AD and can be considered as a potential predictor of the prognosis of lung AD patients. Downregulation of KCND2 may contribute to the therapy of lung AD.

Circ-MMP2 (circ-0039411) induced by FOXM1 promotes the proliferation and migration of lung adenocarcinoma cells in vitro and in vivo

Numerous reports have stated the significance of cellular events such as proliferation, migration and EMT (epithelial-mesenchymal transition) for cancer development, but the related molecular mechanism remains elusive. FOXM1 (forkhead box transcription M1) is a nuclear co-activator participating in lung adenocarcinoma (LUAD). Thus, this study tried to explain the function of FOXM1 and its downstream molecular mechanism in LUAD. We uncovered FOXM1 upregulation in LUAD and demonstrated that FOXM1 facilitated β-catenin nuclear translocation to activate the transcription of downstream genes. Moreover, we discovered that FOXM1 transcriptionally activated circ0039411 which derived from matrix metallopeptidase 2 (MMP2) (also named as circ-MMP2), while MMP2 is a known downstream target of β-catenin. As for functional investigation, knockdown of circ-0039411 suppressed the proliferation, migration and EMT in LUAD cells and also hindered in vivo growth and metastasis of LUAD tumor. Mechanistically, circ-0039411 enhanced the stability of FOXM1 mRNA by recruiting IGF2BP3 (insulin like growth factor 2 mRNA binding protein 3), thus forming a positive feedback loop. In conclusion, this study revealed that FOXM1-induced circ-MMP2 (circ-0039411) contributes to malignant behaviors of LUAD cells via relying on FOXM1, potentially infusing inspirations for the search of new molecular targets for LUAD treatment.

Overexpression of molecule GRP94 favors tumor progression in lung adenocarcinoma by interaction with regulatory T cells.

BackgroundEndoplasmic reticulum stress exists within a tumor. Glucose‐regulated protein 94 (GRP94) is a stress‐induced chaperone protein involved in tumor development and progression. Its role in myeloma, colon cancer, and other tumors has been confirmed, but its role in lung cancer is unclear. This study aimed to determine the role of GRP94 in lung cancer progression and prognostic prediction.MethodsImmunohistochemical staining of GRP94 in human lung adenocarcinoma (AD) and corresponding normal tissue was performed, and its relationship with FOXP3+ regulatory T‐cell (Treg) infiltration analyzed. We investigated the role of GRP94 in the behavior of lung AD cells by inhibiting GRP94 expression in A549 cells. Western blotting was used to detect the TGF‐β/SMAD2 signaling molecules and explore the possible molecular mechanism of GRP94.ResultsGRP94 mRNA (encoded by HSP90B1) and protein levels were upregulated and elevated, respectively, in lung AD compared to normal lung tissues. High GRP94 expression was associated with an advanced disease stage and poor survival. There was a positive correlation between GRP94 expression and FOXP3+ Treg infiltration into lung AD tissues. Our results confirm that GRP94 knockdown inhibits cell proliferation and promotes cell apoptosis by increasing caspase‐7 and CHOP levels in lung AD cells. TGF‐β and SMAD2 protein levels were decreased after GRP94 depletion.ConclusionsOur study revealed that that GRP94 expression in lung AD favors tumor progression and predicts poor prognosis. The oncogenic role of GRP94 may involve inducing Treg infiltration by promoting the TGF‐β signaling pathway.Key points GRP94 protein levels were elevated in lung AD tissues compared to normal lung tissues. The high expression of GRP94 in lung AD favors tumor progression and predicts poor prognosis.The oncogenic role of the molecule GRP94 may involve the stimulation of Treg infiltration via promotion of the TGF‐β signaling pathway.

CtBP1 interacts with SOX2 to promote the growth, migration and invasion of lung adenocarcinoma.

Carboxyl-terminal binding protein 1 (CtBP1) is overexpressed in many types of solid tumors and has been found to be functionally associated with proliferation, migration, invasion and drug resistance of cancer cells. However, its expression pattern and functions in lung adenocarcinoma remain unclear. In the present study, we observed that the expression of CtBP1 was upregulated in the lung adenocarcinoma tissues of patients with lymph node metastasis and that its overexpression was correlated with tumor differentiation, size and poor overall survival. Silencing of CtBP1 by transfection with shRNA inhibited the proliferation, migration and invasion of A459 lung adenocarcinoma cells in vitro as determined by MTT assay and Transwell assay, respectively. In vivo studies using a lung patient-derived tumor xenograft (PDTX) mouse model implicated CtBP1 expression in lung adenocarcinoma growth, and further in vitro co-immunoprecipitation and depletion experiments indicated that CtBP1 regulated the biological behavior of lung adenocarcinoma cells by interacting with SOX2. Patients with elevated expression of both CtBP1 and SOX2 expression had a significantly shorter overall survival rate than patients with reduced expression of these transcripts, or than patients with elevated expression of only one transcript (P<0.01 in both cases). Taken together, these findings suggest that CtBP1 plays an important role in lung adenocarcinoma and, along with SOX2, may serve as a viable prognostic marker and therapeutic target for lung adenocarcinoma.

α1-antitrypsin promotes lung adenocarcinoma metastasis through upregulating fibronectin expression.

α1-antitrypsin (AAT) has been recognized to be associated with lung adenocarcinoma metastasis. However, the mechanisms by which AAT promotes tumor metastasis remain to be investigated. Herein, we first examined AAT expression in a panel of formalin-fixed paraffin-embedded tumor tissues from 88 lung adenocarcinoma patients undergoing curative resection, using immunohistochemical methods. Lung adenocarcinoma patients with high AAT expression showed a significantly shorter overall survival compared to those with low AAT expression by Kaplan-Meier method (P=0.008). High AAT expression was also identified as an independent prognostic factor by Cox regression analysis (adjusted hazard ratio: 2.05; P=0.04). Second, the role of AAT in lung adenocarcinoma cell migration was evaluated in vitro using wound healing and Transwell assays, by transfecting the lentivirus vector with interfering sequence or coding sequence of AAT. The migration property of A549 and SPC-A1 cells was significantly diminished by downregulating AAT expression. Conversely, the migration of both cell lines was significantly increased through upregulating AAT. Furthermore, AAT could increase the expression of fibronectin (FN). FN downregulation reversed AAT-induced promotion of adenocarcinoma cell migration. Third, a cancer cell/endothelial cell co-culture model was established to investigate the effect of AAT on adenocarcinoma cell adhesion using immunofluorescence examination. The results showed that downregulation of AAT inhibited adhesion between lung adenocarcinoma cells and human umbilical vein endothelial cells whereas upregulation of AAT promoted adhesion, which may attribute to interactions between FN and integrin α5. Finally, AAT also showed the regulation effect on the metastatic behavior of lung adenocarcinoma cells in a mouse model, which may be through regulating FN expression. This study suggested that high AAT expression might be a negative prognostic marker for lung adenocarcinoma. AAT promoted lung adenocarcinoma metastasis, whose functional target may be FN. Our findings provide new insight into the mechanisms of lung adenocarcinoma metastasis.