Tumor Suppressor In Lung Cancer Research Articles

METTL3-mediated deficiency of lncRNA HAR1A drives non-small cell lung cancer growth and metastasis by promoting ANXA2 stabilization

We previously reported lncRNA HAR1A as a tumor suppressor in non-small cell lung cancer (NSCLC). However, the delicate working mechanisms of this lncRNA remain obscure. Herein, we demonstrated that the ectopic expression of HAR1A inhibited the proliferation, epithelial-mesenchymal transition (EMT), migration, and invasion of NSCLC cells and enhanced paclitaxel (PTX) sensitivity in vitro and in vivo. We identified the oncogenic protein annexin 2 (ANXA2) as a potential interacting patterner of HAR1A. HAR1A overexpression enhanced ANXA2 ubiquitination and accelerated its degradation via the ubiquitin–proteasome pathway. We further uncovered that HAR1A promoted the interaction between E3 ubiquitin ligase TRIM65 and ANXA2. Moreover, the ANXA2 plasmid transfection could reverse HAR1A overexpression-induced decreases in proliferation, migration, and invasion of NSCLC cells and the activity of the NF-κB signaling pathway. Finally, we found that HAR1A loss in NSCLC might be attributed to the upregulated METTL3. The m6A modification levels of HAR1A were increased in cancer cells, while YTHDF2 was responsible for recognizing m6A modification in the HAR1A, leading to the disintegration of this lncRNA. In conclusion, we found that METTL3-mediated m6A modification decreased HAR1A in NSCLC. HAR1A deficiency, in turn, stimulated tumor growth and metastasis by activating the ANXA2/p65 axis.

Emerging roles of FOXK2 in cancers and metabolic disorders.

FOXK2, a member of the Forkhead box K (FOXK) transcription factor family, is widely expressed in various tissues and organs throughout the body. FOXK2 plays crucial roles in cell proliferation, differentiation, autophagy, de novo nucleotide biosynthesis, DNA damage response, and aerobic glycolysis. Although FOXK2 is recognized as an oncogene in colorectal cancer and hepatocellular carcinoma, it acts as a tumor suppressor in breast cancer, cervical cancer, and non-small cell lung cancer (NSCLC). This review provides an overview of the recent progress in understanding the regulatory mechanisms of FOXK2 and its downstream targets, highlights the significant impact of FOXK2 dysregulation on cancer etiology, and discusses the potential of targeting FOXK2 for cancer treatment.

Abstract 4450: MYC upregulates MCT4 expression and promotes metabolic reprogramming and enhanced lactate utilization in LKB1-deficient NSCLC

Abstract STK11, which encodes the serine/threonine kinase LKB1, is the second most commonly altered tumor suppressor in non-small cell lung cancer (NSCLC). LKB1 loss is frequently co-mutated with KRAS and associated with primary resistance to immunotherapy, which is partially due to MCT4-dependent lactate secretion. However, the mechanisms driving MCT4 elevation and metabolic reprogramming remains unclear. We hypothesized that increased MYC expression, which is associated with LKB1 loss, plays a pivotal role in metabolic alterations, promoting lactate incorporation and maintaining redox homeostasis. To explore the impact of lactate on tumor cells with LKB1 loss, we performed metabolic profiling on KRAS mutant (K) murine lung cancer cells with or without LKB1 knockout (KL) treated with either glucose or lactate as the carbon source. PLS analysis indicated that there was no notable difference between K and KL cells after glucose treatment. However, we observed significant changes in metabolites between K and KL cells when treated with lactate. Differentially altered metabolites included TCA-related components such as acetyl-CoA and glutamate, indicating enhanced lactate utilization in KL tumor cells. We also noticed that KL cells showed increased oxidative phosphorylation (OXPHOS) with the addition of lactate, with increased GSH/GSSH and NADPH/NADP+ ratios, suggesting that, as compared to LKB1-intact cells, LKB1-deficient cells had an enhanced ability to utilize OXPHOS and maintain redox homeostasis with lower levels of ROS generation when utilizing lactate as an energy source. However, in KL cells, MYC knockout (KO) or MCT4 KO partially abolished the lactate-induced OXPHOS and increased ROS. Moreover, [U-13C]lactate tracing revealed that isotopologues were significantly enriched in TCA components in KL cells, and this was reversed by either MYC KO or MCT4 KO, suggesting that MYC and MCT4 were critical for lactate reutilization in KL tumor cells. We observed that MYC could directly bind to the promoter region and transcriptionally activate MCT4 expression, and restoring MCT4 in MYC KO cells enhanced lactate incorporation and decreased ROS levels. Finally, we injected KL murine tumor cells with or without MYC/MCT4 KO into mice and infused [U-13C]lactate to detect the isotopologues distribution in vivo. KL tumors showed significantly enhanced lactate incorporation as compared to K tumors, while MYC KO or MCT4 KO reversed these phenotypes. Collectively, our data indicates that in LKB1-deficient tumors, upregulation of MYC promotes MCT4 expression and increases lactate incorporation and utilization, and that can be inhibited by targeting MYC or MCT4. These findings provide insight into the mechanisms driving the metabolic reprogramming and aggressive phenotype of KRAS-mutant LKB1-deficient tumors and identify a novel therapeutic strategy for this recalcitrant subgroup. Citation Format: Yu Qian, David Molkentine, Yifan Kong, Qian Huang, Chendong Yang, Alissa Poteete, Alvaro P. Guimaraes, Peixin Jiang, Ferdinandos Skoulidis, Alexandre Reuben, John D. Minna, Ralph J. DeBerardinis, John V. Heymach. MYC upregulates MCT4 expression and promotes metabolic reprogramming and enhanced lactate utilization in LKB1-deficient NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4450.

Abstract A178: Therapeutic potential of a p14ARF minimal domain peptide in non-small cell lung cancer

Abstract Many current therapeutic efforts in cancer biology focus on inhibiting the function of aberrant oncogenes whose activities are known to increase proliferation and cell growth. Unfortunately, these efforts have had limited success in lung cancer, where the five-year survival rate remains unchanged. We sought a novel approach; rather than inhibiting oncogenes, we worked to reestablish the function of the p14ARF tumor suppressor in non-small cell lung cancer (NSCLC) to block tumor growth and proliferation. The p14ARF tumor suppressor is encoded by the CDKN2A gene and is the second most commonly mutated gene in NSCLC. p14ARF is known to play a fundamental role in preventing cancer progression by regulating senescence, apoptosis, and proliferation. Here, to determine the minimal functional domain of p14ARF, we generated a panel of p14ARF expression mutants, deleting various amino acids within the known functional and conserved domains of p14ARF. These mutants were then evaluated for their ability to function as wild type p14ARF. Through proliferative and transformative studies, we identified a 10-amino acid domain that is required for p14ARF function. New cell-penetrating peptide technology was employed to determine if these resides were sufficient to elicit antiproliferative effects on their own. We now show that this small region of ARF is capable of entering tumor cells when linked to a cell penetrating peptide. Moreover, this small cell penetrating ARF peptide retains all of ARF’s known tumor suppressor functions. Our findings provide evidence that small cell penetrating peptides are capable of inhibiting tumor cell growth and proliferation. These experiments also lay the foundation for more precise therapeutic peptide cancer treatments, ones that could be used to restore p14ARF tumor suppressor function. Citation Format: Anna L Grobelny, Leonard B Maggi, Jason D Weber. Therapeutic potential of a p14ARF minimal domain peptide in non-small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A178.

Jaceosidin inhibits the progression and metastasis of NSCLC by regulating miR-34c-3p/Integrin α2β1 axis

Non-coding RNAs are crucial for cancer progression, among which miR-34c-3p has been demonstrated to be a tumor suppressor in non-small cell lung cancer (NSCLC). In this study, we attempt to identify flavonoids that can up-regulate miR-34c-3p expression, evaluate the anticancer activity of the flavonoids and explore its underlying mechanism in NSCLC cells. Six flavonoids were screened by RT-qPCR and we found that jaceosidin significantly increased miR-34c-3p expression in A549 cells. We found that jaceosidin inhibited the proliferation, migration and invasion of A549 and H1975 cells in a dose-relevant manner, indicated by cell counting kit (CCK-8) assay, wound healing assay, transwell assay and EdU assay, we observed that jaceosidin inhibited the proliferation, migration and invasion of A549 and H1975 cells in a dose-relevant manner. Further research suggested that miR-34c-3p bound to the transcriptome of integrin α2β1 and then inhibited its expression, leading to the inhibitory effect on the migration and invasion of NSCLC. Our study sheds some light on anti-tumor of jaceosidin and provides a potential lead compound for NSCLC therapy.

MicroRNA-125a-5p as a Tumor Suppressor in Non-Small Cell Lung Cancer (NSCLC): Inhibition of Proliferation and Induction of Apoptosis via P13K/AKT/MMP Signaling Pathway

To investigate the effects of micro ribonucleic acid (miR)-125a-5p on the proliferation and apoptosis of non-small cell lung cancer (NSCLC) cells and its possible mechanism. With NSCLC A549 cells as the experimental research objects, transfection reagent was employed to transfect miR-125a-5p NC group, miR-125a-5p mimic group and miR-125a-5p siRNA group into A549 cells. qRT-PCR and cloning assays were conducted to detect the level of miR125a-5p in A549 cells and the effect of miR125a-5p on the proliferation of A549 cells. The effect of miR-125a-5p on apoptosis of A549 cells was detected via FCM. Additionally, the effects of miR-125a-5p on the mRNA and protein expressions of PI3K and AKT and the expressions of MMP-2 and MMP-9 in A549 cells were determined through qRT-PCR, Western blotting and immunohistochemistry, respectively. Compared with those in miR-125a-5p NC group, the proliferation ability of A549 cells was improved, their apoptosis rate was significantly decreased, and the mRNA and protein levels of PI3K and AKT and the levels of MMP-2 and MMP-9 in A549 cells were increased in miR-125a-5p siRNA group, whereas they showed totally opposite tendencies in miR-125a-5p mimic group. miR-125a-5p overexpression can hinder A549 cell growth, boost apoptosis, and reduce MMP-2 and MMP-9 levels via the PI3K/AKT/MMP pathway.

Statement of Retraction: MicroRNA-422a functions as a tumor suppressor in non-small cell lung cancer through SULF2-mediated TGF-β/SMAD signaling pathway

This article refers to:RETRACTED ARTICLE: MicroRNA-422a functions as a tumor suppressor in non-small cell lung cancer through SULF2-mediated TGF-β/SMAD signaling pathway

Exosomal transfer of miR-195-5p restrains lung adenocarcinoma progression

Exosome is an important way for tumor cells to communicate with other cells and plays an important role in tumor progression. Previous studies revealed that miR-195-5p acts as a tumor suppressor in lung cancer. However, the role and molecular mechanism of exosomal transferred miR-195-5p in lung adenocarcinoma (LAC) remains unknown. Here, we found that miR-195-5p expression in circulating exosomes of LAC patients was lower than that of healthy controls. Meanwhile, the expression of exosomal miR-195-5p from normal bronchial epithelial cell line BEAS-2B cells was significantly higher than that of lung cancer cell lines. The exosome labeling assay confirmed that BEAS-2B cells-derived exosomes could be captured by lung cancer cells. Furthermore, exosomal miR-195-5p derived from BEAS-2B cells remarkably inhibited the proliferation, migration, invasion of lung cancer cells, and tumor growth in vivo. In addition, exosomal miR-195-5p from BEAS-2B cells also suppressed the tube-forming ability of vascular endothelial cells. Moreover, we verified that miR-195-5p decreased apelin (APLN) expression to inactivate the Wnt signaling pathway, thereby inhibiting tumor invasiveness and angiogenesis. In conclusion, our research shows that exosomal miR-195-5p from normal bronchial epithelial cells hinders the progression of LAC, suggesting that regulation of exosomal miR-195-5p provides a novel strategy for LAC treatment.

FAT4 activation inhibits epithelial-mesenchymal transition (EMT) by promoting autophagy in H2228/Cer cells.

As a tumor suppressor in lung cancer, FAT atypical cadherin 4 (FAT4) has a critical role in epithelial-mesenchymal transition (EMT). However, the role of FAT4 in ceritinib-resistant anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer (NSCLC) EMT has not been reported. It is necessary to discuss the role of FAT4 in this process and its potential mechanism of interaction. We found that the expression level of FAT4 was downregulated markedly in ceritinib-resistant NCI-H2228 (H2228/Cer) cells. Jujuboside A, a FAT4 activator, diminished EMT and metastasis of H2228/Cer cells. Importantly, autophagy inhibition inverted the inhibitory effect of FAT4 activation on EMT. Furthermore, we found the regulatory action of FAT4 on autophagy was related to proteasome 26S subunit ubiquitin receptor and non-ATPase 4 (PSMD4) and proteasome 20S subunit beta 4 (PSMB4), and the inhibitory effect of autophagy on EMT might be related to ROS/NF-κB/IκB-α and Wnt/β-catenin pathways. In conclusion, FAT4 activation can inhibit the process of EMT in H2228/Cer cells by promoting autophagy, which provides a potential target for ceritinib-resistant ALK positive NSCLC therapy.

Abstract 821: Dissecting the role of Stag2 in lung adenocarcinoma

Abstract Lung cancer is the most common cause of cancer-related deaths worldwide. Cancers are driven by genomic alterations that activate tumor-promoting oncogenes and inactivate tumor suppressor genes. While some of the most common driver genes have been extensively characterized, many tumor suppressor genes are less well studied. A better understanding of the mechanisms by which different tumor suppressor genes constrain tumorigenesis has the potential to uncover unappreciated biological processes that influence carcinogenesis. Recently, we performed an in vivo screen within a genetically engineered mouse model of oncogenic KRAS-driven lung cancer and found that STAG2 inactivation dramatically increases tumor growth. While STAG2 is mutated in ~4% of human lung adenocarcinomas, 20% of lung adenocarcinomas are low or negative for STAG2 protein. STAG2 is a subunit of one of the two major cohesin complexes, which are present in all cell types and have been implicated in many different cellular processes. STAG2 has not previously been recognized as a critical tumor suppressor in lung cancer and the mechanism through which its inactivation drives lung tumor growth is unknown. Immunohistochemistry, low-pass whole genome sequencing, and analysis of canonical target genes suggest that STAG2 inactivation is not associated with mechanisms previously implicated in other cancer types including chromosomal instability, increased DNA damage, or the activation of MEK/ERK or cGAS/STING signaling. Interesting, we have found that Stag2 is the only cohesin subunit that functions as a tumor suppressor in lung cancer in vivo. Chromatin accessibility profiling and gene expression analyses on Stag2-proficient and -deficient mouse lung adenocarcinoma cells have unveiled potential mediators and effects of STAG2 function. Ongoing genomic analyses of human and mouse lung cancers will demystify the relationship between major cohesin complexes, uncover the impact of STAG2 inactivation on cohesin binding genome wide, and investigate the role of Stag2 inactivation on the tumor microenvironment. We anticipate that our study will uncover the mechanisms of STAG2-mediated tumor suppression in lung cancer and provide novel insights into lung tumorigenesis. Citation Format: Emily L. Ashkin, Hongchen Cai, Yuning J. Tang, Chuan Li, Su Kit Chew, King Hung, Julia Belk, Saswati Karmakar, Jess Hebert, Maryam Yousefi, Charles Swanton, Dmitri A. Petrov, Monte Winslow. Dissecting the role of Stag2 in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 821.

Retraction for Motiwala et al., Protein tyrosine phosphatase receptor-type O (PTPRO) exhibits characteristics of a candidate tumor suppressor in human lung cancer

Retraction for Motiwala et al., Protein tyrosine phosphatase receptor-type O (PTPRO) exhibits characteristics of a candidate tumor suppressor in human lung cancer

Artesunate Suppresses the Growth of Lung Cancer Cells by Downregulating the AKT/Survivin Signaling Pathway.

NSCLC (non-small-cell lung cancer) is the deadliest cancer in the world. Artesunate is one of the most potent and rapidly acting antimalarial agents. Recently, emerging evidence has suggested the anticancer function of artesunate. In our work, we aimed to investigate the molecular mechanism of artesunate-induced growth inhibition in human lung adenocarcinoma cells and reported that the anticancer effects of artesunate is related to its ability in downregulating AKT/Survivin signaling in A549 cells. The effect of artesunate on the proliferation of A549 cells was determined by CCK-8 assay and colony formation assay; its effect on A549 cell apoptosis was evaluated by lactate dehydrogenase (LDH) release assay. The role of artesunate on the activation of AKT/Survivin signaling was analyzed by western blot and quantitative QPCR. Finally, we used two mouse tumor models to investigate the function of artesunate on the in vivo growth of lung cancer cells. Artesunate treatment caused significant growth inhibition and apoptosis in A549 cells. Mechanistically, artesunate downregulated the activation of AKT/Survivin signaling. In agreement, hyperactivation of AKT signaling restored artesunate-induced growth inhibition in A549 cells. In mouse lung cancer models, artesunate administration significantly reduced the growth of A549 cells and LLC cells in nude mice and immunocompetent mice, respectively. Our findings suggest that artesunate serves as a potential tumor suppressor in lung cancer and hopefully can provide new insight into the development of therapeutic strategies in the clinical lung cancer treatment.

Circular RNA circ-PLCD1 functions as a tumor suppressor in non-small cell lung cancer by inactivation of PI3K/AKT signaling pathway.

Circular RNAs (circRNAs) are emerging as crucial regulators in tumorigenesis and aggressive progression. However, their biological roles in non-small cell lung cancer (NSCLC) remain largely unknown. Here, by performing circRNA high throughput sequencing in 4 paired NSCLC and normal tissues, we found a NSCLC-associated circRNA, circ-PLCD1, which was evidently downregulated in NSCLC tissues and cell lines. Circ-PLCD1 was transcriptionally activated by tumor-inhibiting protein p53, and exogenous expression of circ-PLCD1 inhibited NSCLC cell proliferation, invasion and induced apoptosis. Mechanistically, circ-PLCD1 acted as a competitive endogenous RNA (ceRNA) to sponge miR-375 and miR-1179 and elevate PTEN, a well-known inhibitor of oncogenic PI3K/AKT signaling, thereby repressing NSCLC tumorigenesis. Importantly, we also identified this ceRNA regulatory axis of circ-PLCD1/miR-375/miR-1179/PTEN in vivo by establishing a xenograft tumor model. Clinically, NSCLC patients with low circ-PLCD1 expression had larger tumor size, later clinical stage and shorter survival time than those with high circ-PLCD1 expression. Altogether, our findings reveal the important tumor suppressive role of circ-PLCD1 in NSCLC, reactivation of this circRNA may be considered as a novel therapeutic avenue for patient with NSCLC.

LACTB suppresses carcinogenesis in lung cancer and regulates the EMT pathway.

Lung cancer causes thousands of deaths worldwide every year, and present therapeutics show little benefit for advanced-stage patients. Researchers do not know why and how lung cancer begins. Lactamase β (LACTB) is a tumor-suppressor in some cancers. However, its role in lung cancer is unknown. By analyzing the TCGA database and Kaplan-Meier Plotter database, LACTB was found to be downregulated in lung cancer tissues but the methylation level was increased. Patients with high LACTB expression exhibited improved survival. Then, in vitro assays demonstrated that LACTB overexpression inhibited cell migration and invasion, and induced apoptosis in H1299 and H1975 cells. Knockdown of LACTB caused the reverse effects. Moreover, a much higher apoptotic rate and more potent inhibitory effects on H1299 and H1975 cells were obtained when LACTB was combined with docetaxel. In addition, members of the epithelial-mesenchymal transition (EMT) signaling pathway were assessed using western blot analysis. The expression of E-cadherin was decreased while levels of N-cadherin and vimentin were increased after knockdown of LACTB in lung cancer cells. By contrast, overexpression of LACTB increased the level of E-cadherin but decreased N-cadherin and vimentin. Therefore, LACTB is a tumor suppressor in lung cancer that inhibits cell migration and invasion and induces cell apoptosis. Meanwhile, LACTB was found to strengthen the anticancer role of docetaxel and to suppress the EMT pathway in lung cancer.

Gene expression profiling using targeted RNA-sequencing to elucidate the progression from histologically normal lung tissues to non-invasive lesions in invasive lung adenocarcinoma.

Lung adenocarcinoma (LUAD) shows heterogeneous morphological features and the stepwise progression from adenocarcinoma in situ to minimally invasive adenocarcinoma to invasive LUAD. Although multiple genetic alterations have been linked to the progression, the differences between the gene expression profiles of non-invasive lesions (non-ILs) and adjacent histologically normal lung (aNL) tissues within invasive LUAD have not been investigated. Herein, we analyzed differentially expressed genes (DEGs) specific to early-stage carcinogenesis in LUAD. Invasive LUAD tissue samples containing both non-ILs and aNL tissues were obtained from seven patients with pathological stage I LUAD, and each component was subjected to microdissection. Gene expression profiles of each component were determined using targeted RNA-sequencing. In total, 2536 DEGs, including 863 upregulated and 1673 downregulated genes, were identified in non-ILs. In non-ILs, the expression of SLC44A5, a choline transporter-like protein-coding gene, was significantly upregulated, and that of TMEM100, a gene encoding a transmembrane protein, was significantly downregulated. Reportedly, SLC44A5 plays an important role in the development and progression of hepatocellular carcinoma, whereas TMEM100 functions as a tumor suppressor in non-small cell lung cancer. Gene set enrichment analysis showed that DEGs in non-ILs were negatively enriched in cell death and immune response. Immunohistochemical analysis revealed that increased SLC44A5 expression and decreased TMEM100 expression were maintained in ILs. A protein-protein interaction (PPI) network analysis identified several upregulated and downregulated hub genes with high degrees in non-ILs. In conclusion, several new DEGs and key PPI network hub genes were identified in non-ILs, contributing to understanding of early-stage carcinogenesis in LUAD.

Overexpression of 15-Hydroxyprostaglandin Dehydrogenase Inhibits A549 Lung Adenocarcinoma Cell Growth via Inducing Cell Cycle Arrest and Inhibiting Epithelial-Mesenchymal Transition.

PurposeLung cancer is one of the most commonly diagnosed cancer as well as the leading cause of cancer-related mortality worldwide, among which lung adenocarcinoma (LUAD) is the most frequent form of lung cancer. Previous studies have shown that 15-hydroxyprostaglandin dehydrogenase (15-PGDH) catalyzes the oxidation of prostaglandins to reduce their biological activities and behaves as a tumor suppressor in various cancers. Thus, we aimed to systematically examine the effects of 15-PGDH overexpression on cellular processes in lung adenocarcinoma cells.MethodsThe stable 15-PGDH-overexpressing A549 cell line was constructed using lentivirus particles. CCK-8 assay was used to determine the cell proliferation rate and sensitivity to cisplatin. Tandem mass tag (TMT)-based quantitative proteomic analysis was used to identify differentially expressed proteins between control and 15-PGDH-overexpression cells. The cell cycle was determined by a flow cytometer. The expression levels of mesenchymal and epithelial markers were measured using Western blotting. Wound healing and transwell assays were used to detect the cell migration and cell invasion ability, respectively.ResultsAnalysis of datasets in The Cancer Genome Atlas revealed that the PGDH gene expression level in the lung adenocarcinoma tissues was significantly lower than that in the pericarcinous tissues. 15-PGDH overexpression in A549 cells reduced cell proliferation rate. Quantitative proteomics revealed that 15-PGDH overexpression inhibited PI3K/AKT/mTOR signaling pathway, which is a signaling pathway driving tumor cell growth and epithelial-mesenchymal transition (EMT) process. In addition, both cell cycle and DNA repair-related proteins were down-regulated in 15-PGDH overexpressed cells. 15-PGDH overexpression induced G1/S cell cycle arrest and increased susceptibility to DNA damaging reagent cisplatin. Importantly, overexpression of 15-PGDH inhibited EMT process with the downregulation of β-catenin and Snail-1 as well as upregulation of E-cadherin and ZO-1.Conclusion15-PGDH is a tumor suppressor in lung cancer and may serve as a potential therapeutic target to prevent lung adenocarcinoma.

The role of miRNA-377 as a tumor suppressor in lung cancer by negative regulation of genes belonging to ErbB signaling pathway

The ErbB signaling pathway plays important role in the pathogenesis of lung cancer. We explored the role of miRNA-377 as a tumor suppressor in NSCLC through silencing of some genes in the ErbB pathway. The targeting effect of miRNA-377 on EGFR, MAPK1, ABL2, and PAK2 was evaluated. The expression levels of these genes and miRNA-377 were surveyed in NSCLC and normal human tissues, Calu-6, and A549 cells. Real-time PCR was used to figure out whether miRNA-377 could decrease the target genes mRNAs in transfected lung cancer cell lines. The effects of miRNA-377 on apoptosis cell and proliferation were analyzed. We showed that miRNA-377 targets EGFR, MAPK1, and PAK2 mRNAs in in-silico and luciferase reporter assay. The expression of miRNA-377 was significantly downregulated in human NSCLC tissues, Calu-6 and A549 cells compared to their controls. We observed a negative correlation between EGFR, MAPK1, PAK2, and miRNA-377 expression in human NSCLC tissues. A significant reduction in EGFR, MAPK1, and PAK2 mRNA levels was detected, following miRNA-377 transfection in Calu-6 and A549 cells. The higher levels of miRNA-377 in Calu-6, and A549 cells induced apoptosis and reduced proliferation, significantly. All these data reveal that miRNA-377 functions as a tumor suppressor in NSCLC and may serve as a potential therapeutic target for the treatment of NSCLC.

The CADM1 tumor suppressor gene is a major candidate gene in MDS with deletion of the long arm of chromosome 11

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis leading to peripheral cytopenias and in a substantial proportion of cases to acute myeloid leukemia. The deletion of the long arm of chromosome 11, del(11q), is a rare but recurrent clonal event in MDS. Here, we detail the largest series of 113 cases of MDS and myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) harboring a del(11q) analyzed at clinical, cytological, cytogenetic, and molecular levels. Female predominance, a survival prognosis similar to other MDS, a low monocyte count, and dysmegakaryopoiesis were the specific clinical and cytological features of del(11q) MDS. In most cases, del(11q) was isolated, primary and interstitial encompassing the 11q22-23 region containing ATM, KMT2A, and CBL genes. The common deleted region at 11q23.2 is centered on an intergenic region between CADM1 (also known as Tumor Suppressor in Lung Cancer 1) and NXPE2. CADM1 was expressed in all myeloid cells analyzed in contrast to NXPE2. At the functional level, the deletion of Cadm1 in murine Lineage-Sca1+Kit+ cells modifies the lymphoid-to-myeloid ratio in bone marrow, although not altering their multilineage hematopoietic reconstitution potential after syngenic transplantation. Together with the frequent simultaneous deletions of KMT2A, ATM, and CBL and mutations of ASXL1, SF3B1, and CBL, we show that CADM1 may be important in the physiopathology of the del(11q) MDS, extending its role as tumor-suppressor gene from solid tumors to hematopoietic malignancies.

LncRNA XIST Contributes to Cisplatin Resistance of Lung Cancer Cells by Promoting Cellular Glycolysis through Sponging miR-101-3p

Background: Non-small-cell lung carcinoma is one of the most frequently diagnosed cancers. Cisplatin (CDDP) is a currently applied standard anticancer agent for advanced lung cancers. Although effectively clinical response was achieved initially, a large fraction of lung cancer patients developed cisplatin resistance. Therefore, understanding the molecular mechanisms of chemoresistance is crucial for anti-lung cancer therapy. Long non-coding RNA (lncRNA)-X-inactive-specific transcript (XIST) has been reported to be positively associated with multiple cancers. Currently, the precise role and mechanism of XIST in cisplatin resistance of lung cancer have not been elucidated. Methods: The expression levels of miR-101-3p and lncRNA XIST were detected by qRT-PCR. Cisplatin-resistant lung cancer cell line was established by selecting the survival cells under gradually increased cisplatin treatments. The cell proliferation was detected by MTT assay, and the cellular glucose metabolism rate was evaluated by Seahorse metabolic flux analysis and glucose uptake and lactate product assays. Glycolysis-related protein expression levels were detected by Western blot. Dual luciferase reporter was constructed to determine the lncRNA-miRNA interaction. Results: Here, we report XIST is significantly upregulated in lung cancer tissues compared with normal lung tissues. In addition, cisplatin-resistant lung cancer cells displayed remarkably elevated XIST expression. We demonstrated that miR-101-3p functioned as a tumor suppressor in lung cancer and sensitized lung cancer cells to cisplatin. Bioinformatics analysis predicted miR-101-3p could be a potential target of XIST through direct binding with it as a competing endogenous RNA, which was further validated from lung tumor tissues and cell lines by luciferase assay. Intriguingly, XIST significantly promoted cellular glycolysis rate of lung cancer cells. The extracellular acidification rate, glucose uptake, and lactate product were elevated by XIST overexpression. On the contrary, miR-101-3p effectively suppressed glycolysis rate. Finally, we demonstrated silencing XIST significantly recovered miR-101-3p expression and downregulated expression of glycolysis key enzymes, a phenotype could be further overridden by miR-101-3p inhibition. Conclusions: This study reveals a new molecular mechanism for the lncRNA-XIST-promoted cisplatin resistance via sponging miR-101-3p, leading to de-repression of cellular glycolysis. Moreover, these findings warrant further in vivo investigations to study XIST as a potential target to overcome cisplatin resistance.

LncRNA AC079630.4 expression associated with the progression and prognosis in lung cancer.

Mounting evidence has demonstrated the important role of long non-coding RNAs (lncRNAs) in the development and progression of lung cancer. In this study, we combined the methods of bioinformatics analysis and experimental validation, and aim to investigate the clinical significance and underlying mechanism of the novel lncRNA AC079630.4 in lung cancer. Finally, we found that AC079630.4 was significantly down-regulated in lung cancer tissues, including in its subtypes. Samples with low AC079630.4 expression had a more advanced pathological stage and a worse prognosis than those with high expression. In functional prediction, the KEGG pathway of apoptosis and the TRAIL signaling pathway were enriched in the samples with high AC079630.4 expression. In experimental validation, AC079630.4 over-expression could significantly inhibit the proliferation and clonality, and up-regulated the receptors of TRAIL (TRAIL-R1 and TRAIL-R2) in lung cancer cells. In conclusion, we adopted the methods of bioinformatics analysis and experimental validation, and identified a novel lncRNA of AC079630.4 as a tumor suppressor in lung cancer.