Sex specific function of epithelial STAT3 signaling in pathogenesis of K-ras mutant lung cancer.
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ABSTRACT:
SUBMITTER: Caetano MS
PROVIDER: S-EPMC6214980 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionTyrosine phosphorylated signal transducer and activator of transcription 3 (pStat3) is present in numerous cancers and is required for mediating tumorigenesis. Autocrine and paracrine interleukin (IL)-6 signaling is the principal mechanism by which Stat3 is persistently phosphorylated in epithelial tumors including breast, lung, colon and gastric cancer. The Ras oncogene mediates cellular transformation without evidence of pStat3 in cultured cells. Recently, however non-tyrosine phosphorylated Stat3 was shown to have a transcriptional activating function, a role in mitochondrial function and to mediate cell migration.. Here we examined the role of Stat3 in Ras mediated transformation.MethodsHa-rasV12 transformed mammary epithelial cells (MCF10A) cells were transduced with a Stat3shRNA, IL-6shRNA and/or treated with inhibitors of Janus kinases (JAKs) to examine the role of the IL-6 signaling pathway in Ras mediated invasion and tumorigenesis.ResultsCellular migration, invasion, anchorage independent growth and tumorigenesis were largely abrogated in the Stat3-reduced cells compared to control cells. Analysis of MCF10A-Ras tumors revealed high levels of pStat3 and interleukin-6. Tumors derived from transgenic MMTV-K-Ras mice were also found to express pStat3 and IL-6. MCF10A-Ras cells, when grown in a three-dimensional Matrigel culture system revealed the appearance of the junctional protein E-Cadherin as a consequence of reducing Stat3 levels or inhibiting Stat3 activity. Decreasing IL-6 levels in the MCF10A-Ras cells abrogated tumorigenesis and reduced cell migration. By isolating Ras-expressing primary tumors and serially passaging these cells in two-dimensional culture led to a decrease in IL-6 and pStat3 levels with the reappearance of E-Cadherin.ConclusionsThe cellular and environmental context can lead to differential IL-6/pStat3 signaling and a dependency on this cytokine and transcription factor for migration, invasion and tumorigenesis.
| S-EPMC3096973 | biostudies-literature
Project description:Chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, is an independent risk factor for lung cancer. Lung tissues obtained from human smokers with COPD and lung cancer demonstrate hypoxia and up-regulated hypoxia inducible factor-1 (HIF-1). HIF-1 activation is the central mechanism for controlling the cellular response to hypoxia during inflammation and tumor development. These facts suggest a link between COPD-related airway inflammation, HIF-1, and lung cancer. We have previously established a mouse model of COPD-like airway inflammation that promotes lung cancer in a K-ras mutant mouse model (CC-LR). Here we show that tumors in the CC-LR model have significantly elevated levels of HIF-1? and HIF-1 activity. To determine the tumor-promoting functions of HIF-1 in CC-LR mice, the gene Hif1a which encodes HIF-1? and is required for HIF-1 activity, was disrupted in the lung epithelium of CC-LR animals. Airway epithelial specific HIF-1? deficient mice demonstrated significant reductions in lung surface tumor numbers, tumor angiogenesis, and tumor cell proliferation in the absence or presence of COPD-like airway inflammation. In addition, when CC-LR mice were bred with transgenic animals that overexpress a constitutively active mutant form of human HIF-1? in the airway epithelium, both COPD- and adenocarcinoma-like phenotypes were observed. HIF-1? overexpressing CC-LR mice had significant emphysema, and they also showed potentiated tumorigenesis, angiogenesis, and cell proliferation accompanied by an invasive metastatic phenotype. Our gain and loss of function studies support a key role for HIF-1? in the promotion of lung cancer by COPD-like inflammation.
| S-EPMC6152479 | biostudies-literature
Project description:Investigating whether DNA methylation (DNA-M) at an earlier age is associated with lung function at a later age and whether this relationship differs by sex could enable prediction of future lung function deficit. A training/testing-based technique was used to screen 402 714 cytosine-phosphate-guanine dinucleotide sites (CpGs) to assess the longitudinal association of blood-based DNA-M at ages 10 and 18 years with lung function at 18 and 26 years, respectively, in the Isle of Wight birth cohort (IOWBC). Multivariable linear mixed models were applied to the CpGs that passed screening. To detect differentially methylated regions (DMRs), DMR enrichment analysis was conducted. Findings were further examined in the Avon Longitudinal Study of Parents and Children (ALSPAC). Biological relevance of the identified CpGs was assessed using gene expression data. DNA-M at eight CpGs (five CpGs with forced expiratory volume in 1 s (FEV1) and three CpGs with FEV1/forced vital capacity (FVC)) at an earlier age was associated with lung function at a later age regardless of sex, while at 13 CpGs (five CpGs with FVC, three with FEV1 and five with FEV1/FVC), the associations were sex-specific (p FDR <0.05) in IOWBC, with consistent directions of association in ALSPAC (IOWBC-ALSPAC consistent CpGs). cg16582803 (WNT10A) and cg14083603 (ZGPAT) were replicated in ALSPAC for main and sex-specific effects, respectively. Among IOWBC-ALSPAC consistent CpGs, DNA-M at cg01376079 (SSH3) and cg07557690 (TGFBR3) was associated with gene expression both longitudinally and cross-sectionally. In total, 57 and 170 DMRs were linked to lung function longitudinally in males and females, respectively. CpGs showing longitudinal associations with lung function have the potential to serve as candidate markers in future studies on lung function deficit prediction.
| S-EPMC8255542 | biostudies-literature
Project description:BackgroundmiRNAs play crucial role in the progression of K-Ras-mutated nonsmall cell lung cancer (NSCLC). However, most studies have focused on miRNAs that target K-Ras. Here, we investigated miRNAs regulated by mutant K-Ras and their functions.MethodsmiRNAs regulated by mutant K-Ras were screened using miRNA arrays. miR-199b expression levels were measured by qRT-PCR. The protein expression levels were measured using Western blot and immunohistochemistry. The effects of miR-199b on NSCLC were examined both in vitro and in vivo by overexpressing or inhibiting miR-199b. DNA methylation was measured by bisulfite sequencing.ResultsAn inverse correlation was observed between K-Ras mutation status and miR-199b levels in NSCLC specimens and cell lines. The inhibition of miR-199b stimulated NSCLC growth and metastasis, while restoration of miR-199b suppressed K-Ras mutation-driven lung tumorigenesis as well as K-Ras-mutated NSCLC growth and metastasis. miR-199b inactivated ERK and Akt pathways by targeting K-Ras, KSR2, PIK3R1, Akt1, and Rheb1. Furthermore, we determined that mutant K-Ras inhibits miR-199b expression by increasing miR-199b promoter methylation.ConclusionOur findings suggest that mutant K-Ras plays an oncogenic role through downregulating miR-199b in NSCLC and that overexpression of miR-199b is a novel strategy for the treatment of K-Ras-mutated NSCLC.
| S-EPMC6466664 | biostudies-literature
Project description:K-ras mutations are associated with smoking-induced lung cancer and poor clinical outcomes. In mice, K-ras mutations are sufficient to induce lung tumors, which require phosphoinoside-3-kinase (PI3K) and further downstream, mammalian target of rapamycin (mTOR) activation. However, the roles of individual Akt isoforms that link PI3K and mTOR are unknown. Here, we show that deletion of Akt1 but not Akt2 or Akt3 prevents lung tumorigenesis in a tobacco carcinogen-induced model and a genetic model. Akt1 deletion prevented tumor initiation as well as tumor progression, coincident with decreased Akt signaling in tumor tissues. In contrast, deletion of Akt3 increased tumor multiplicity in the carcinogen model and increased tumor size in the genetic model. Fibroblasts lacking Akt1 are resistant to transformation by mutant K-ras and stimulation by epidermal growth factor. Human lung cancer cells with mutant K-ras and diminished Akt1 levels fail to grow in vivo. These data suggest that Akt1 is the primary Akt isoform activated by mutant K-ras in lung tumors, and that Akt3 may oppose Akt1 in lung tumorigenesis and lung tumor progression. Given that Akt inhibitors in clinical development as cancer therapeutics are not isoform selective, these studies support specific targeting of Akt1 to mitigate the effects of mutant K-ras in lung cancer.
| S-EPMC4133779 | biostudies-literature
Project description:UNLABELLED:Lung cancer commonly displays a number of recurrent genetic abnormalities, and about 30% of lung adenocarcinomas carry activating mutations in the Kras gene, often concomitantly with inactivation of tumor suppressor genes p16(INK4A) and p14(ARF) of the CDKN2AB locus. However, little is known regarding the function of p15INK4B translated from the same locus. To determine the frequency of CDKN2AB loss in human mutant KRAS lung cancer, The Cancer Genome Atlas (TCGA) database was interrogated. Two-hit inactivation of CDKN2A and CDKN2B occurs frequently in patients with mutant KRAS lung adenocarcinoma. Moreover, p15INK4B loss occurs in the presence of biallelic inactivation of p16(INK4A) and p14(ARF), suggesting that p15INK4B loss confers a selective advantage to mutant KRAS lung cancers that are p16(INK4A) and p14(ARF) deficient. To determine the significance of CDKN2AB loss in vivo, genetically engineered lung cancer mouse models that express mutant Kras in the respiratory epithelium were utilized. Importantly, complete loss of CDKN2AB strikingly accelerated mutant Kras-driven lung tumorigenesis, leading to loss of differentiation, increased metastatic disease, and decreased overall survival. Primary mutant Kras lung epithelial cells lacking Cdkn2ab had increased clonogenic potential. Furthermore, comparative analysis of mutant Kras;Cdkn2a null with Kras;Cdkn2ab null mice and experiments with mutant KRAS;CDKN2AB-deficient human lung cancer cells indicated that p15INK4B is a critical tumor suppressor. Thus, the loss of CDKN2AB is of biologic significance in mutant KRAS lung tumorigenesis by fostering cellular proliferation, cancer cell differentiation, and metastatic behavior. IMPLICATIONS:These findings indicate that mutant Kras;Cdkn2ab null mice provide a platform for accurately modeling aggressive lung adenocarcinoma and testing therapeutic modalities.
| S-EPMC4058359 | biostudies-literature
Project description:Signal transducer and activator of transcription 3 (STAT3) is a point of convergence for numerous oncogenic signals that are often constitutively activated in many cancerous or transformed cells and some stromal cells in the tumor microenvironment. Persistent STAT3 activation in malignant cells stimulates proliferation, survival, angiogenesis, invasion, and tumor-promoting inflammation. STAT3 undergoes activation through phosphorylation on tyrosine 705, which facilitates its dimerization. Dimeric STAT3 translocates to the nucleus, where it regulates the transcription of genes involved in cell proliferation, survival, etc. In the present study, a synthetic deguelin analogue SH48, discovered by virtual screening, inhibited the phosphorylation, nuclear translocation, and transcriptional activity of STAT3 in H-ras transformed human mammary epithelial MCF-10A cells (MCF10A-ras). We speculated that SH48 bearing an ?,?-unsaturated carbonyl group could interact with a thiol residue of STAT3, thereby inactivating this transcription factor. Non-electrophilic analogues of SH48 failed to inhibit STAT3 activation, lending support to the above supposition. By utilizing a biotinylated SH48, we were able to demonstrate the complex formation between SH48 and STAT3. SH48 treatment to MCF10A-ras cells induced autophagy, which was verified by staining with a fluorescent acidotropic probe, LysoTracker Red, as well as upregulating the expression of LC3II and p62. In conclusion, the electrophilic analogue of deguelin interacts with STAT3 and inhibits its activation in MCF10A-ras cells, which may account for its induction of autophagic death.
| S-EPMC7600869 | biostudies-literature
Project description:Animal models demonstrate that aberrant gene expression in utero can result in abnormal pulmonary phenotypes.We sought to identify genes that are differentially expressed during in utero airway development and test the hypothesis that variants in these genes influence lung function in patients with asthma.Stage 1 (Gene Expression): Differential gene expression analysis across the pseudoglandular (n = 27) and canalicular (n = 9) stages of human lung development was performed using regularized t tests with multiple comparison adjustments. Stage 2 (Genetic Association): Genetic association analyses of lung function (FEV(1), FVC, and FEV(1)/FVC) for variants in five differentially expressed genes were conducted in 403 parent-child trios from the Childhood Asthma Management Program (CAMP). Associations were replicated in 583 parent-child trios from the Genetics of Asthma in Costa Rica study.Of the 1,776 differentially expressed genes between the pseudoglandular (gestational age: 7-16 wk) and the canalicular (gestational age: 17-26 wk) stages, we selected 5 genes in the Wnt pathway for association testing. Thirteen single nucleotide polymorphisms in three genes demonstrated association with lung function in CAMP (P < 0.05), and associations for two of these genes were replicated in the Costa Ricans: Wnt1-inducible signaling pathway protein 1 with FEV(1) (combined P = 0.0005) and FVC (combined P = 0.0004), and Wnt inhibitory factor 1 with FVC (combined P = 0.003) and FEV(1)/FVC (combined P = 0.003).Wnt signaling genes are associated with impaired lung function in two childhood asthma cohorts. Furthermore, gene expression profiling of human fetal lung development can be used to identify genes implicated in the pathogenesis of lung function impairment in individuals with asthma.
| S-EPMC2822972 | biostudies-literature
Project description:The Janus tyrosine kinases JAK1-3 and tyrosine kinase-2 (TYK2) are frequently hyperactivated in tumors. In lung cancers JAK1 and JAK2 induce oncogenic signaling through STAT3. A putative role of TYK2 in these tumors has not been reported. Here, we show a previously not recognized TYK2-STAT3 signaling node in lung cancer cells. We reveal that the E3 ubiquitin ligase seven-in-absentia-2 (SIAH2) accelerates the proteasomal degradation of TYK2. This mechanism consequently suppresses the activation of STAT3. In agreement with these data the analysis of primary non-small-cell lung cancer (NSCLC) samples from three patient cohorts revealed that compared to lung adenocarcinoma (ADC), lung squamous cell carcinoma (SCC) show significantly higher levels of SIAH2 and reduced STAT3 phosphorylation levels. Thus, SIAH2 is a novel molecular marker for SCC. We further demonstrate that an activation of the oncologically relevant transcription factor p53 in lung cancer cells induces SIAH2, depletes TYK2, and abrogates the tyrosine phosphorylation of STAT1 and STAT3. This mechanism appears to be different from the inhibition of phosphorylated JAKs through the suppressor of cytokine signaling (SOCS) proteins. Our study may help to identify molecular mechanisms affecting lung carcinogenesis and potential therapeutic targets.
| S-EPMC4102802 | biostudies-other
Project description:The receptor tyrosine kinase KIT promotes survival and migration of melanocytes during development, and excessive KIT activity hyperactivates the RAS/MAPK pathway and can drive formation of melanomas, most notably of rare melanomas that occur on volar and mucosal surfaces of the skin. The much larger fraction of melanomas that occur on sun-exposed skin is driven primarily by BRAF- or NRAS-activating mutations, but these melanomas exhibit a surprising loss of KIT expression, which raises the question of whether loss of KIT in these tumors facilitates tumorigenesis. To address this question, we introduced a kit(lf) mutation into a strain of Tg(mitfa:BRAFV600E); p53(lf) melanoma-prone zebrafish. Melanoma onset was accelerated in kit(lf); Tg(mitfa:BRAFV600E); p53(lf) fish. Tumors from kit(lf) animals were more invasive and had higher RAS/MAPK pathway activation. KIT knockdown also increased RAS/MAPK pathway activation in a BRAFV600E-mutant human melanoma cell line. We found that pathway stimulation upstream of BRAFV600E could paradoxically reduce signaling downstream of BRAFV600E, and wild-type BRAF was necessary for this effect, suggesting that its activation can dampen oncogenic BRAFV600E signaling. In vivo, expression of wild-type BRAF delayed melanoma onset, but only in a kit-dependent manner. Together, these results suggest that KIT can activate signaling through wild-type RAF proteins, thus interfering with oncogenic BRAFV600E-driven melanoma formation. Cancer Res; 77(21); 5820-30. ©2017 AACR.
| S-EPMC5679278 | biostudies-literature