USP22 promotes tumor progression and induces epithelial–mesenchymal transition in lung adenocarcinoma

ObjectivesOur previous study showed that USP22 as an oncogene may mediate cancer development and progression in NSCLC, but the underlying molecular mechanism remains uncharacterized. Epithelial–mesenchymal transition (EMT) has been reported to play an important role in migration and invasion of the tumor cells. Thus, this study aims to determine the clinical significance and the possible roles of USP22 in EMT and progression of lung adenocarcinoma.MethodsImmunohistochemistry was used to determine the expression of USP22 in clinical samples. The clinical correlations and prognostic significance of the aberrantly expressed proteins were evaluated by statistical analysis. Moreover, we evaluated whether USP22 could induce EMT in cultured lung cancer cells.ResultsThe USP22 expression was positive in 76.03% of specimens and was correlated with advanced clinicopathologic classifications (differentiation, T and AJCC stages) and TGF-β1 expression (p = 0.008). Multivariate Cox regression analysis revealed that USP22 expression level was an independent prognostic factor for both overall survival and disease-free survival (HR, 2.060; p = 0.013 and HR, 1.993; p = 0.016). In vitro study revealed that USP22 can regulate proliferation and invasive properties, and induce EMT of lung adenocarcinoma cells. Moreover, USP22 may up-regulate TGF-β1 expression.ConclusionsOur data indicated that USP22 may promote lung adenocarcinoma cell invasion by the induction of EMT.     

Targeting polymerase θ impairs tumorigenesis and enhances radiosensitivity in lung adenocarcinoma

Radioresistance remains a major obstacle to efficacious radiotherapy in non–small-cell lung cancer (NSCLC). DNA replication proteins are novel targets for radiosensitizers. POLQ is a DNA polymerase involved in DNA damage response and repair. We found that POLQ is overexpressed in NSCLC and is clinically correlated with high tumor stage, poor prognosis, increased tumor mutational burden, and ALK and TP5 mutation status; POLQ inhibition impaired lung tumorigenesis. Notably, POLQ expression was higher in radioresistant lung cancer cells than in wild-type cancer cells. Moreover, POLQ expression was further increased in radioresistant cells after radiation. Enhanced radioresistance is through a prolonged G2/M phase and faster repair of DNA damage, leading to reduced radiation-induced apoptosis. Novobiocin (NVB), a POLQ inhibitor, specifically targeted cancer cells. Genetic knockdown of POLQ or pharmacological inhibition by NVB decreased radioresistance in lung adenocarcinoma while causing little toxicity to normal pulmonary epithelial cells. In conclusion, POLQ is a promising and practical cancer-specific target to impair tumorigenesis and enhance radiosensitivity in NSCLC.     

The nonsmokers’ and smokers’ pathways in lung adenocarcinoma: Histological progression and molecular bases

There could be two carcinogenetic pathways for lung adenocarcinoma (LADC): the nonsmokers’ pathway and the smokers’ pathway. This review article describes the two pathways with special reference to potential relationships between histological subtypes, malignant grades, and driver mutations. The lung is composed of two different tissue units, the terminal respiratory unit (TRU) and the central airway compartment (CAC). In the nonsmokers’ pathway, LADCs develop from the TRU, and their histological appearances change from lepidic to micropapillary during the progression process. In the smokers’ pathway, LADCs develop from either the TRU or the CAC, and their histological appearances vary among cases in the middle of the progression process, but they are likely converged to acinar/solid at the end. On a molecular genetic level, the nonsmokers’ pathway is mostly driven by EGFR mutations, whereas in the smokers’ pathway, approximately one-quarter of LADCs have KRAS mutations, but the other three-quarters have no known driver mutations. p53 mutations are an important factor triggering the progression of both pathways, with unique molecular alterations associated with each, such as MUC21 expression and chromosome 12p13-21 amplification in the nonsmokers’ pathway, and HNF4α expression and TTF1 mutations in the smokers’ pathway. However, investigation into the relationship between histological progression and genetic alterations is in its infancy. Tight cooperation between traditional histopathological examinations and recent molecular genetics can provide valuable insight to better understand the nature of LADCs.     

Functional MUC4 suppress epithelial–mesenchymal transition in lung adenocarcinoma metastasis

The mucin MUC4 is a high molecular weight membrane-bound transmembrane glycoprotein that is frequently detected in invasive and metastatic cancer. The overexpression of MUC4 is associated with increased risks for several types of cancer. However, the functional role of MUC4 is poorly understood in lung adenocarcinoma. Using antisense-MUC4-RNA transfected adenocarcinoma cells, we discovered that the loss of MUC4 expression results in epithelial–mesenchymal transition (EMT). We found morphological alterations and the repression of the epithelial marker E-cadherin in transfected cells. Additionally, the loss of MUC4 caused the upregulation of the mesenchymal marker vimentin compared to control cells. Using a MUC4-knockdown versus control LTEP xenograft mice model (129/sv mice), we also found that EMT happened in lung tissues of MUC4-knockdown-LTEP xenograft mice. Moreover, antisense-MUC4-RNA transfected cells had a significantly increased cellular migration ability in vitro. The loss of MUC4 also occurred in lung adenocarcinoma patients with lymph node metastases. We further investigated MUC4 and found that it plays a critical role in regulating EMT by modulating β-catenin. Taken together, our study reveals a novel role for MUC4 in suppressing EMT and suggests that the assessment of MUC4 may function as a prognostic biomarker and could be a potential therapeutic target for lung adenocarcinoma metastasis.     

JAK／STAT信号通路与急性白血病

JAK／STAT信号通路是由多种细胞因子与受体结合激活的中心通路,参与肿瘤的增殖、分化和凋亡过程。研究表明,血液细胞中JAK／STAT突变及调控异常对急性白血病发生发展起重要作用。探讨此通路的异常有望为治疗急性白血病提供新靶点。     

Expression of the tumor suppressor miR-206 is associated with cellular proliferative inhibition and impairs invasion in ERα-positive endometrioid adenocarcinoma

This study investigated the role of miR-206 in estrogen receptor-α (ERα)-positive endometrial endometrioid adenocarcinoma (EEC). We profiled miR-206 expression in 30 EEC clinical samples using qRT-PCR, and explored its relationship with ERα and clinical parameters. A luciferase reporter assay assessed the ERα targeting potential of miR-206. Functional analyses of miR-206 were performed in EEC cell lines. MiRNA-206 expression decreased in ERα-positive EECs, and its expression was negatively correlated with ERα. MiRNA-206 overexpression inhibited ERα-dependent proliferation, impaired invasiveness and induced cell cycle arrest of ERα-positive EEC cell lines. Therefore, aberrantly expressed miRNA-206 may be associated with the development of ERα-positive EEC.     

Stepwise progression of pulmonary adenocarcinoma—clinical and molecular implications

Stepwise progression of pulmonary adenocarcinoma is described from the viewpoint of both pathology and molecular biology. Pulmonary adenocarcinoma develops to invasive carcinoma through atypical adenomatous hyperplasia, adenocarcinoma in situ and minimally invasive adenocarcinoma. The Noguchi classification is well correlated with this sequential histological progression. On the other hand, in terms of molecular biology, p16 gene inactivation, EGFR mutation and KRAS mutation are early events, and tumors progress to invasive adenocarcinoma as a result of p53 mutation, loss of various chromosomes and other genetic abnormalities.     

JAK–STAT signalling controls cancer stem cell properties including chemotherapy resistance in myxoid liposarcoma

Myxoid liposarcoma (MLS) shows extensive intratumoural heterogeneity with distinct subpopulations of tumour cells. Despite improved survival of MLS patients, existing therapies have shortcomings as they fail to target all tumour cells. The nature of chemotherapy-resistant cells in MLS remains unknown. Here, we show that MLS cell lines contained subpopulations of cells that can form spheres, efflux Hoechst dye and resist doxorubicin, all properties attributed to cancer stem cells (CSCs). By single-cell gene expression, western blot, phospho-kinase array, immunoprecipitation, immunohistochemistry, flow cytometry and microarray analysis we showed that a subset of MLS cells expressed JAK–STAT genes with active signalling. JAK1/2 inhibition via ruxolitinib decreased, while stimulation with LIF increased, phosphorylation of STAT3 and the number of cells with CSC properties indicating that JAK–STAT signalling controlled the number of cells with CSC features. We also show that phosphorylated STAT3 interacted with the SWI/SNF complex. We conclude that MLS contains JAK–STAT-regulated subpopulations of cells with CSC features. Combined doxorubicin and ruxolitinib treatment targeted both proliferating cells as well as cells with CSC features, providing new means to circumvent chemotherapy resistance in treatment of MLS patients.     

Do all lung adenocarcinomas follow a stepwise progression?

Similar to the adenoma–carcinoma sequence of colorectal cancer, lung adenocarcinoma is thought to follow a linear multistep progression, in which a precursor lesion progresses to adenocarcinoma in situ, which is followed by invasive adenocarcinoma. However, lung adenocarcinoma can no longer be considered as a single type of tumor but rather a group of distinct subsets of tumors that arise from different molecular pathways. Consistent with this concept, recent findings revealed that this linear progression might not occur in all lung adenocarcinomas. First, according to the molecular classification based on expression profiling, lung cancer can be divided into at least two subsets; precancerous and in situ lesions share characteristics of molecular expression and clinical features with only one of the two subsets, suggesting that the linear progression is only applicable to the subset in the molecular classification. Second, when EGFR and KRAS were examined based on the progression steps, the mutation rate of KRAS was disproportionally distributed; however, according to the progression schema, gene alterations should be evenly accumulated along the entire progression. Third, by means of comparative genomic hybridization analysis, some adenocarcinoma in situ revealed gene alterations discontinuous to invasive adenocarcinoma. Finally, there were some clinical observations that support that some lesions escape from the progression. In this review, we hypothesize a novel scenario for the progression of lung adenocarcinoma, which does not support a linear progression schema.     

MicroRNA-451 induces epithelial–mesenchymal transition in docetaxel-resistant lung adenocarcinoma cells by targeting proto-oncogene c-Myc

Epithelial–mesenchymal transition (EMT) has been reported to play a significant role in tumour metastasis as well as chemoresistance. However, the molecular mechanisms involved in chemotherapy-induced EMT are still unclear. MicroRNA (miRNA) expression and functions have been reported to contribute to phenotypic features of tumour cells. To investigate the roles of miRNAs in chemotherapy-induced EMT, we established two docetaxel-resistant lung adenocarcinoma (LAD) cell models (SPC-A1/DTX and H1299/DTX), which display EMT-like properties and gain increased invasion or migration activity. MiR-451 was found to be significantly downregulated in docetaxel-resistant LAD cells, and re-expression of miR-451 could reverse EMT to mesenchymal–epithelial transition (MET) and inhibit invasion and metastasis of docetaxel-resistant LAD cells both in vitro and in vivo. The proto-oncogene c-Myc was identified as a direct and functional target of miR-451, and further researches confirmed that overexpression of c-Myc which induced extracellular-signal-regulated kinase (ERK)-dependent glycogen synthase kinase-3 beta (GSK-3β) inactivation and subsequent snail activation is essential for acquisition of EMT phenotype induced by loss of miR-451. Furthermore, c-Myc was significantly upregulated in docetaxel-non-responding LAD tissues in comparison with docetaxel-responding tissues, and its expression was inversely correlated with miR-451 expression. This study first reported the involvement of miR-451/c-Myc/ERK/GSK-3β signalling axis in the acquisition of EMT phenotype in docetaxel-resistant LAD cells, suggesting that re-expression of miR-451 or targeting c-Myc will be a potential strategy for the treatment of chemoresistant LAD patients.     

Activation of Akt involves resistance to NF-κB inhibition and abrogation of both triggers synergistic apoptosis in lung adenocarcinoma cells

Objectives

Although nuclear factor (NF)-κB and phosphoinositide 3-kinase (PI3K)-Akt-mTOR comprise key pathways, their interrelationship in lung cancer cell survival is poorly understood and needs further analyses.

Materials and methods

We examined the activation of the NF-κB and Akt-mTORC1-p70 S6 kinase (S6K) pathways and the effect of inhibitors for NF-κB, mTORC1, and Akt using fresh lung adenocarcinoma cells.

Results

The cases used for this study showed constitutive NF-κB activity; however, all cases but one showed resistance to NF-κB inhibition. Further examination revealed that the resistant cases were also active in the Akt-mTORC1-S6K pathway. These cases were insensitive to mTORC1 inhibition but sensitive to Akt inhibition. Akt inhibition recovered sensitivity to NF-κB inhibition and dual inhibition showed a synergistic effect on apoptosis induction.

Conclusion

These results indicate that the activation of Akt involves resistance to NF-κB inhibition and both pathways synergistically support the survival of lung adenocarcinoma cells. The results also indicate that inhibition of the mTORC1-S6K pathway does not inhibit the survival of these cells.     

Biomarkers for immune checkpoint inhibition in non–small cell lung cancer (NSCLC)

The emergence of immunotherapy has dramatically changed how non–small cell lung cancer is treated, and longer survival is now possible for some patients, even those with advanced disease. Although some patients achieve durable responses to checkpoint blockade, not all experience such benefits, and some suffer from significant immunotoxicities. Given this, biomarkers that predict response to therapy are essential, and testing for tumor programmed death ligand 1(PD-L1) expression is the current standard. The extent of PD-L1 expression determined by immunohistochemistry (IHC) has demonstrated a correlation with treatment response, although limitations with this marker exist. Recently, tumor mutational burden has emerged as an alternative biomarker, and studies have demonstrated its utility, irrespective of the PD-L1 level of a tumor. Gene expression signatures, tumor genotype (such as the presence of an oncogenic driver mutation), as well as the density of tumor-infiltrating lymphocytes in the tumor microenvironment also seem to affect response to immunotherapy and are being researched. Peripheral serum markers are being studied, and some have demonstrated predictive ability, although most are still investigational and need prospective validation. In the current article, the authors review the biomarker PD-L1 as well as other emerging and investigational tissue-based and serum-based markers that have potential to better predict responders to immunotherapy.     

Targeting NF-κB in mouse models of lung adenocarcinoma

Xue et al. demonstrate response and increased survival but development of acquired resistance to proteasome and inhibitor-κB kinase inhibitors targeting NF-κB activation in adenocarcinomas of Kras-activated, p53-deficient mice.     

Norcantharidin impairs medulloblastoma growth by inhibition of Wnt/β-catenin signaling

Medulloblastoma is one of the leading causes of morbidity and mortality in pediatric cancer. Wnt-active tumors, an independent molecular subgroup in medulloblastoma, are characterized by a distinct pattern of genomic aberrations. We assessed the anticancer activity of cantharidin and norcantharidin against medulloblastoma, as cell lines in vitro and in athymic nude mice in vivo. Cantharidin and norcantharidin treatment impaired the growth of DAOY and UW228 medulloblastoma cells and promoted the loss of β-catenin activation and the β-catenin nuclearization linked to N-cadherin impairment in vitro. Intra-peritoneal administration of norcantharidin inhibited the growth of intra-cerebellum tumors in orthotopic xenograft nude mice. Analysis of the xenograft tissues revealed enhanced neuronal differentiation and reduced β-catenin expression. Our findings suggest that norcantharidin has potential therapeutic applications in the treatment of medulloblastoma as a result of its ability to cross the blood–brain barrier and its impairment of Wnt-β-catenin signaling.