Notch1 phenotype and clinical stage progression in non-small cell lung cancer

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

A comprehensive integrated gene network construction to explore the essential role of Notch 1 in lung adenocarcinoma (LUAD)

The heterogeneous biological landscape of non-small cell lung cancer (NSCLC) is largely attributed to the activation of Notch signalling pathway. Among the Notch family transmembrane proteins, neurogenic locus notch homolog protein1 (NOTCH1) is a putative oncogene in NSCLC which activates the pathway as negative prognostic factor. This study aims to explore integrated network approach in lung adenocarcinoma (LUAD) especially linked to the notch pathway and its receptors. Our gene set enrichment analysis reveals the key Notch pathway genes are predominantly down regulated in LUAD. There were 675 genes with a total of 6517 functional interactions and 6 densely connected clusters of 38 miRNAs, 84 transcription factors with 156 edges identified through network construction. Here we report five key genes namely NOTCH1, CDH1, ERBB2, GAPDH and COL1A1 significantly enriched in Notch pathway which are further validated through the KM plot, box plots, stage plots and TIMER analysis. In addition, the NOTCH1 receptor is strongly linked to the immune checkpoint inhibitor CD274 (PD-L1) and can be considered as prognostic marker and tumour suppressor gene in LUAD which surely provide the basis for early diagnosis and futuristic immunotherapeutic targets for LUAD.

Lung Cancer Stem Cell Markers as Therapeutic Targets: An Update on Signaling Pathways and Therapies

Cancer stem cells, a relatively small group of self-renewing cancer cells, were first isolated from acute myeloid leukemia. These cells can play a crucial role in tumor metastasis, relapse, and therapy resistance. The cancer stem cell theory may be applied to lung cancer and explain the inefficiency of traditional treatments and eventual recurrence. However, because of the unclear accuracy and illusive biological function of cancer stem cells, some researchers remain cautious about this theory. Despite the ongoing controversy, cancer stem cells are still being investigated, and their biomarkers are being discovered for application in cancer diagnosis, targeted therapy, and prognosis prediction. Potential lung cancer stem cell markers mainly include surface biomarkers such as CD44, CD133, epithelial cell adhesion molecule, and ATP-binding cassette subfamily G member 2, along with intracellular biomarkers such as aldehyde dehydrogenase, sex-determining region Y-box 2, NANOG, and octamer-binding transcription factor 4. These markers have different structures and functions but are closely associated with the stem potential and uncontrollable proliferation of tumor cells. The aberrant activation of major signaling pathways, such as Notch, Hedgehog, and Wnt, may be associated with the expression and regulation of certain lung cancer stem cell markers, thus leading to lung cancer stem cell maintenance, chemotherapy resistance, and cancer promotion. Treatments targeting lung cancer stem cell markers, including antibody drugs, nanoparticle drugs, chimeric antigen receptor T-cell therapy, and other natural or synthetic specific inhibitors, may provide new hope for patients who are resistant to conventional lung cancer therapies. This review provides comprehensive and updated data on lung cancer stem cell markers with regard to their structures, functions, signaling pathways, and promising therapeutic target approaches, aiming to elucidate potential new therapies for lung cancer.

TET2 and DNMT3A mutations and exceptional response to 4'-thio-2'-deoxycytidine in human solid tumor models

Background

Challenges remain on the selection of patients who potentially respond to a class of drugs that target epigenetics for cancer treatment. This study aims to investigate TET2/DNMT3A mutations and antitumor activity of a novel epigenetic agent in multiple human cancer cell lines and animal models.

Methods

Seventeen cancer cell lines and multiple xenograft models bearing representative human solid tumors were subjected to 4′-thio-2′-deoxycytidine (T-dCyd) or control treatment. Gene mutations in cell lines were examined by whole exome and/or Sanger sequencing. Specific gene expression was measured in cells and xenograft tumor samples by Western blotting and immunohistochemistry. TET2/DNMT3A mutation status in 47,571 human tumor samples was analyzed at cBioPortal for Cancer Genomics.

Results

Cell survival was significantly inhibited by T-dCyd in breast BT549, lung NCI-H23, melanoma SKMEL5 and renal ACHN cancer lines harboring deleterious TET2 and nonsynonymous DNMT3A mutations compared to 13 lines without such mutation pattern (P = 0.007). The treatment upregulated p21 and induced cell cycle arrest in NCI-H23 cells, and dramatically inhibited their xenograft tumor growth versus wildtype models. T-dCyd administrations led to a significant p21 increase and near eradication of tumor cells in the double-mutant xenografts by histological evaluation. TET2/DNMT3A was co-mutated in human lung, breast, skin and kidney cancers and frequently in angioimmunoblastic and peripheral T cell lymphomas and several types of leukemia.

Conclusions

Cell and animal models with concurrent mutations in TET2 and DNMT3A were sensitive to T-dCyd treatment. The mutations were detectable in human solid tumors and frequently occur in some hematological malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01091-5.

Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) in non-small cell lung cancer

Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is a transcription factor that can regulate downstream target gene expression. Kelch-like ECH-associated protein 1 (Keap1) negatively regulates Nrf2 activation and translocation to target its 26S proteasomal degradation. It has been widely reported that the Keap1/Nrf2 pathway is associated with tumorigenesis, chemotherapy resistance and progression and development of non-small cell lung cancer (NSCLC). High expression of Nrf2 and low abundance of Keap1 contribute to the abnormalities and unrealistic treatment prognosis of NSCLC. Therefore, elucidating the role and potential mechanism of Nrf2 in NSCLC is essential for understanding tumorigenesis and for the development of strategies for effective clinical management. Here, we summarize current knowledge about the molecular structure and biological function of Nrf2, and we discuss the roles of Nrf2 in tumorigenesis, which will further provide a possible therapeutic strategy for NSCLC.

Novel ADAM-17 inhibitor ZLDI-8 inhibits the proliferation and metastasis of chemo-resistant non-small-cell lung cancer by reversing Notch and epithelial mesenchymal transition in vitro and in vivo

Acquired drug-resistant non-small cell lung cancer (NSCLC) has strong proliferation ability and is prone to epithelial-mesenchymal transition (EMT) and subsequent metastasis. Notch pathway mediates cell survival and EMT and is involved in the induction of multidrug resistance (MDR). ZLDI-8 is an inhibitor of Notch activating/cleaving enzyme ADAM-17 we found before. However, the effects of ZLDI-8 on resistant NSCLC was unclear. Here, we demonstrated for the first time that ZLDI-8 could induce apoptosis in lung cancer, especially in chemotherapy-resistant non-small cell lung cancer cells, and also inhibit migration, invasion and EMT phenotype of drug-resistant lung cancer. ZLDI-8 inhibits the Notch signaling pathway, thereby regulating the expression of survival/apoptosis and EMT-related proteins. Moreover, ZLDI-8 suppresses multidrug-resistant lung cancer xenograft growth in vivo and blocks metastasis in a tail vein injection mice model. Therefore, ZLDI-8 is expected to be an effective agent in the treatment of drug-resistant lung cancer.

Single nucleotide polymorphism rs3124599 in Notch1 is associated with the risk of lung cancer in northeast Chinese non-smoking females

Lung cancer is one of the most common cancers and the main cause of cancer-related deaths. Notch1 might play a part in tumorigenesis of lung cancer. Here we explored the relationship of three SNPs (rs3124599, rs3124607 and rs3124594) in Notch1 with the risk and the survival of lung cancer in non-smoking females, including 556 cases and 395 controls. Chi-square tests, logistic regression analysis and crossover analysis were conducted to estimate the association between SNPs and the risk of lung cancer and the interaction between SNPs and environmental exposure. Survival analysis was conducted to explore the association between SNPs and survival of lung cancer. The results demonstrated that the polymorphism of rs3124599 was associated with the susceptibility of lung cancer in recessive model (AA+AG vs. GG). Compared to the those with AA or AG genotype, individuals with GG genotype had a 1.562-fold increased risk of lung cancer (P = 0.023, OR = 1.562, 95% CI = 1.062-2.297). In stratified analysis, the GG genotype of rs3124599 would increase the risk of small cell lung cancer (SCLC) (P = 0.011, OR = 2.167, 95% CI = 1.193-3.396). However, no significant interaction between rs3124599 and cooking oil fume exposure was observed either in addictive model or multiplicative model. The results of survival analysis showed there was no significant association between SNPs and prognosis of lung cancer (P = 0.949 for rs3124599, P = 0.508 for rs3124607, P = 0.884 for rs3124594). Our study might indicate that rs312599 in Notch1 may be a novel biomarker for SCLC risk in Chinese non-smoking females.

Notch signaling and non-small cell lung cancer

Lung cancer is the leading cause of cancer-associated mortality worldwide. Elucidation of the pathogenesis and biology of lung cancer is critical for the design of an effective treatment for patients. Non-small cell lung cancer (NSCLC) accounts for 80–85% of lung cancer cases. The abnormal expression of Notch signaling pathway members is a relatively frequent event in NSCLC. The Notch signaling pathway serves important roles in cell fate determination, proliferation, differentiation and apoptosis. Increasing evidence supports the association of Notch signaling dysregulation with various types of malignant tumor, including NSCLC. Several studies have demonstrated that members of the Notch signaling pathway may be potential biomarkers for predicting the progression and prognosis of patients with NSCLC. Furthermore, Notch signaling serves critical roles in the tumorigenesis and treatment resistance of NSCLC cells by promoting the proliferation or inhibiting the apoptosis of NSCLC cells. The present review provides a detailed summary of the roles of Notch signaling in NSCLC.

Downregulation of long non-coding RNA LET predicts poor prognosis and increases Notch signaling in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) have been found to be dysregulated in a variety of tumors. The lncRNA-Low Expression in Tumor (LET) is a recently identified lncRNA, but its expression pattern and biological significance in human non-small cell lung cancer (NSCLC) are still largely unknown. In this study, we found that lncRNA-LET was significantly downregulated in human NSCLC lung tissues and cell lines. Decreased lncRNA-LET expression was strongly associated with advanced tumor stages and poorer overall survival of NSCLC patients. Functionally, overexpression of lncRNA-LET in NSCLC H292 cells significantly suppressed cell proliferation, migration and invasion, and promoted cell cycle arrest and apoptosis, while knockdown of lncRNA-LET in NSCLC H1975 cells showed an opposite effect, pointing to a tumor-suppressive role for lncRNA-LET in NSCLC. Mechanistically, we demonstrated that lncRNA-LET overexpression significantly reduced the expression of Notch1 intracellular Domain (NICD1) in H292 cells while knockdown of lncRNA-LET increased NICD1 expression in H1975 cells. Similarly, NSCLC lung tissues with high levels of lncRNA-LET had lower NICD1 expression. Thus, our results provide a strong rationale for lncRNA-LET to be used as a prognostic indicator and a potent therapeutic target for NSCLC patients, and highlight a novel lncRNA-LET/Notch axis in regulating NSCLC cell fate and tumor progression.

Prognostic roles of mRNA expression of notch receptors in non-small cell lung cancer

Notch signalling is aberrantly activated in human non-small cell lung cancer (NSCLC). Nevertheless, the prognostic roles of mRNA expression of four Notch receptors in NSCLC patients remain elusive. In this report, we reported the prognostic roles of Notch receptors in a total of 1,926 NSCLC patients through “The Kaplan-Meier plotter” (KM plotter) database which is capable to assess the effect of 22,277 genes on survival of NSCLC patients. We found that mRNA high expression level of Notch1 was associated with better overall survival (OS) for all NSCLC patients, hazard ratio (HR) 0.78 (0.69-0.89), p=0.00019, better OS in adenocarcinoma (Ade) patients, HR 0.59 (0.46-0.75), p=1.5e-05, as well as in squamous cell carcinoma (SCC) patients, HR 0.78 (0.62-0.99), p=0.044. mRNA high expression levels of Notch2 and Notch3 were associated with worsen OS for all NSCLC patients, as well as in Ade, but not in SCC patients. mRNA high expression level of Notch4 was not found to be associated with to OS for all NSCLC patients. In addition, mRNA high expression levels of Notch2, Notch3, but Notch4 are significantly associated with the NSCLC patients who have different smoking status. Our results indicate that mRNA expression of Notch receptors may have distinct prognostic values in NSCLC patients. These results will benefit for developing tools to accurately predict the prognosis of NSCLC patients.

Effects of the Notch1 signaling pathway on human lung cancer A549 cells

PURPOSE

To evaluate the effects of the Notch1 signaling pathway on human lung cancer A549 cells.

MATERIALS AND METHODS

A549 cells were transfected with recombinant plasmids. Cell proliferation was detected by MTT assay. A tumor-bearing mouse model was established for intratumoral gene injection. Apoptosis-related factors were detected by immunohistochemical assay. Caspase-8, caspase-3, caspase-9, PI3K, pAkt and pSTAT3 expressions were detected by Western blotting.

RESULTS

Compared with A549-GFP and A549 cells, A549-ICN cell growth in mice decelerated, tumor volume significantly reduced (p < 0.01), and survival time significantly increased (p < 0.05). Cyclin E and phosphorylated Rb protein expressions were significantly down-regulated. Compared with control, apoptosis-related protein Bcl-2 expression in tumors injected with Notch1 gene was significantly inhibited. After Deltex1 transfection, A549 cell proliferation decelerated, growth was significantly inhibited (p < 0.05), and survival time was significantly extended (p < 0.05). Cyclin E and mutant p53 protein expressions in tumors were down-regulated, phosphorylated Rb expression was almost completely inhibited, and Bcl-2 expression was significantly inhibited. TNF-α-related apoptosis-inducing ligand (TRAIL) inhibited A549-ICN cell growth time- and dose-dependently. After treatment for 24 h or longer, TRAIL induced apoptosis of more A549-ICN cells. Cleaved caspase-3 and cleaved caspase-9 were detected only in A549-ICN cells after 6 h of 40 ng/mL TRAIL treatment, but cleaved caspase-8 was not detected. Combining Notch1 signal with TRAIL inhibited PI3K, phosphorylated Akt and phosphorylated STAT3 expressions.

CONCLUSION

The Notch1 signaling pathway may inhibit A549 cell growth in vitro and in vivo by regulating cell cycle-related and anti-apoptotic protein expressions. Notch1 activation also suppressed A549 cell apoptosis by inhibiting the PI3K/pAkt pathway and activating the caspase-3 pathway in cooperation with TRAIL.

Luteolin suppresses gastric cancer progression by reversing epithelial-mesenchymal transition via suppression of the Notch signaling pathway

BACKGROUND

Gastric cancer (GC) is one of the most malignant tumors and the second leading cause of cancer-related deaths in the world. Luteolin, a flavonoid present in many fruits and green plants, suppresses cancer progression. The effects of luteolin on GC cells and their underlying mechanisms remain unclear.

METHODS

Effects of luteolin on cell proliferation, migration, invasion, and apoptosis were examined in vitro and in vivo by cell counting kit-8 (CCK-8), transwell assays, and flow cytometry, respectively. Real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blots were performed to evaluate Notch1 signaling and activation of epithelial-mesenchymal transition (EMT) in GC cells treated with or without luteolin. Immunohistochemistry was performed to examine proliferation and Notch1 expression in xenograft tumors.

RESULTS

Luteolin significantly inhibited cell proliferation, invasion, and migration in a dose-dependent and time-dependent manner and promoted cell apoptosis. Luteolin reversed EMT by shrinking the cytoskeleton and by inducing the expression of epithelial biomarker E-cadherin and downregulating the mesenchymal biomarkers N-cadherin, vimentin and Snail. Furthermore, Notch1 signaling was inhibited by luteolin, and downregulation of Notch1 had similar effects as luteolin treatment on cell proliferation, migration, and apoptosis. In addition, luteolin suppressed tumor growth in vivo. A higher expression of Notch1 correlated with a poor overall survival and a poor time to first progression. Furthermore, co-immunoprecipitation analysis revealed that activated Notch1 and β-catenin formed a complex and regulated cell proliferation, migration, and invasion.

CONCLUSIONS

In this study, GC progression was inhibited by luteolin through suppressing Notch1 signaling and reversing EMT, suggesting that luteolin may serve as an effective anti-tumor drug in GC treatment.

Prognostic significance of Notch ligands in patients with non-small cell lung cancer

The Notch signaling pathway is deregulated in numerous solid types of cancer including non-small cell lung cancer (NSCLC). However, the profile of Notch ligand expression remains unclear. Therefore, the present study aimed to determine the profile of Notch ligands in NSCLC patients and to investigate whether quantitative assessment of Notch ligand expression may have prognostic significance in NSCLC patients. The study was performed in 61 pairs of tumor and matched unaffected lung tissue specimens obtained from patients with various stages of NSCLC, which were analyzed by reverse transcription-polymerase chain reaction. The marked expression levels of certain analyzed genes were detected in NSCLC samples and in noncancerous lung samples. Of the five Notch ligands, jagged 1 (Jag1), jagged 2, delta-like protein 1 and delta-like protein 4 were expressed in the majority of tissues, but their expression levels were reduced in NSCLC when compared with noncancerous lung tissue (P<0.001). Delta-like protein 3 expression was consistently low and was observed only in 21/61 tumor tissue samples. Taken together, Notch ligands are expressed in NSCLC. However, the expression level is reduced when compared to noncancerous tissue. Furthermore, the present study revealed that quantitative assessment of Jag1 expression in NSCLC may improve prognostication of patient survival.

Regulation of the epithelial to mesenchymal transition and metastasis by Raf kinase inhibitory protein-dependent Notch1 activity

Raf kinase inhibitory protein (RKIP), an endogenous inhibitor of the extracellular signal-regulated kinase (ERK) pathway, has been implicated as a suppressor of metastasis and a prognostic marker in cancers. However, how RKIP acts as a suppressor during metastasis is not fully understood. Here, we show that RKIP activity in cervical and stomach cancer is inversely correlated with endogenous levels of the Notch1 intracellular domain (NICD), which stimulates the epithelial to mesenchymal transition (EMT) and metastasis. The levels of RKIP were significantly decreased in tumor tissues compared to normal tissues, whereas NICD levels were increased. Overexpression of RKIP in several cell lines resulted in a dramatic decrease of NICD and subsequent inhibition of several mesenchymal markers, such as vimentin, N-cadherin, and Snail. In contrast, knockdown of RKIP exhibited opposite results both in vitro and in vivo using mouse models. Nevertheless, knockdown of Notch1 in cancer cells had no effect on the expression of RKIP, suggesting that RKIP is likely an upstream regulator of the Notch1 pathway. We also found that RKIP directly interacts with Notch1 but has no influence on the intracellular level of the γ-secretase complex that is necessary for Notch1 activation. These data suggest that RKIP plays a distinct role in activation of Notch1 during EMT and metastasis, providing a new target for cancer treatment.

Therapeutic target discovery and drug development in cancer stem cells for leukemia and lymphoma: from bench to the clinic

INTRODUCTION

Cancer stem cells (CSCs), also known as tumor initialing cells, have self-renewal capacity and are believed to play an important role in residual disease or tumor relapse. CSCs exhibit characteristic slow growth rate and are resistant to conventional chemotherapy/radiotherapy in experimental models. The type of cells commonly employs aberrant activity of the embryonic signal transduction pathways - Notch, Hedgehog (Hh), and Wnt - for uncontrolled proliferation and survival. Areas covered: The following article discusses key genetic and molecular alterations in Notch, Hh and Wnt pathways and drugs targeting the alterations for the treatment of leukemia and lymphoma. Expert opinion: Early signs of signal agent activity have been observed in certain types of leukemia and lymphoma with experimental therapeutics targeting the embryonic pathways in the CSC signaling network. However, clinical development of agents that inhibit the Wnt/β-catenin, Notch and Hh signaling appear to be more complex in relapsed or refractory malignancies. A strategy to effectively target signaling may rely on early application of biomarkers representative of the active signaling nodes companion to the molecularly targeted agents. Biomarkers for efficacy could potentially guide selective treatment of hematological malignancies or cancer with drugs that target the embryonic pathways.

Redox Signaling and Bioenergetics Influence Lung Cancer Cell Line Sensitivity to the Isoflavone ME-344

ME-344 [(3R,4S)-3,4-bis(4-hydroxyphenyl)-8-methyl-3,4-dihydro-2H-chromen-7-ol] is a second-generation derivative natural product isoflavone presently under clinical development. ME-344 effects were compared in lung cancer cell lines that are either intrinsically sensitive or resistant to the drug and in primary immortalized human lung embryonic fibroblasts (IHLEF). Cytotoxicity at low micromolar concentrations occurred only in sensitive cell lines, causing redox stress, decreased mitochondrial ATP production, and subsequent disruption of mitochondrial function. In a dose-dependent manner the drug caused instantaneous and pronounced inhibition of oxygen consumption rates (OCR) in drug-sensitive cells (quantitatively significantly less in drug-resistant cells). This was consistent with targeting of mitochondria by ME-344, with specific effects on the respiratory chain (resistance correlated with higher glycolytic indexes). OCR inhibition did not occur in primary IHLEF. ME-344 increased extracellular acidification rates in drug-resistant cells (significantly less in drug-sensitive cells), implying that ME-344 targets mitochondrial proton pumps. Only in drug-sensitive cells did ME-344 dose-dependently increase the intracellular generation of reactive oxygen species and cause oxidation of total (mainly glutathione) and protein thiols and the concomitant immediate increases in NADPH levels. We conclude that ME-344 causes complex, redox-specific, and mitochondria-targeted effects in lung cancer cells, which differ in extent from normal cells, correlate with drug sensitivity, and provide indications of a beneficial in vitro therapeutic index.

Notch signaling in lung diseases: focus on Notch1 and Notch3

Notch signaling is an evolutionarily conserved cell–cell communication mechanism that plays a key role in lung homeostasis, injury and repair. The loss of regulation of Notch signaling, especially Notch1 and Notch3, has recently been linked to the pathogenesis of important lung diseases, in particular, chronic obstructive pulmonary disease (COPD), asthma, pulmonary fibrosis, pulmonary arterial hypertension (PAH), lung cancer and lung lesions in some congenital diseases. This review focuses on recent advances related to the mechanisms and the consequences of aberrant or absent Notch1/3 activity in the initiation and progression of lung diseases. Our increasing understanding of this signaling pathway offers great hope that manipulating Notch signaling may represent a promising alternative complementary therapeutic strategy in the future.

Emerging roles of Nrf2 signal in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) causes considerable mortality in the world. Owing to molecular biological progress, treatments in adenocarcinoma have evolved revolutionarily while those in squamous lung cancer remain unsatisfied. Recent studies revealed high-frequency alteration of Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-like factor 2 (Keap1/Nrf2) pathway within squamous lung cancer, attracting researchers to focus on this particular pathway. In NSCLC patients, deregulated Nrf2 signal is recognized as a common feature at both DNA and protein level. Emerging associations between Nrf2 and other pathways have been elucidated. MicroRNA was also implicated in the regulation of Nrf2. Agents activating or antagonizing Nrf2 showed an effect in preclinical researches, reflecting different effects of Nrf2 during tumor initiation and progression. Prognostic evaluation demonstrated a negative impact of Nrf2 signal on NSCLC patients’ survival. Considering the importance of Nrf2 signal in NSCLC, further studies are required in the future.

Roles of NOTCH1 as a Therapeutic Target and a Biomarker for Lung Cancer: Controversies and Perspectives

Lung cancer is one of the most common types of human malignancies and the leading cause of cancer-related death. Patients with surgically resectable early stage lung cancer are more likely curable, but currently only a small population of patients can be diagnosed at such a stage, partly due to our incomplete understanding of the biology of lung cancer and the lack of diagnostic and prognostic biomarkers. Recent studies have shown that NOTCH1 is a critical regulator of human carcinogenesis and has been implicated in multiple steps of cancer development and progression. Herein, we review recent findings about the role of NOTCH1 in lung cancer and discuss its potential usefulness as both a therapeutic target and a biomarker for lung cancer.

Targeting Notch, Hedgehog, and Wnt pathways in cancer stem cells: clinical update

During the past decade, cancer stem cells (CSCs) have been increasingly identified in many malignancies. Although the origin and plasticity of these cells remain controversial, tumour heterogeneity and the presence of small populations of cells with stem-like characteristics is established in most malignancies. CSCs display many features of embryonic or tissue stem cells, and typically demonstrate persistent activation of one or more highly conserved signal transduction pathways involved in development and tissue homeostasis, including the Notch, Hedgehog (HH), and Wnt pathways. CSCs generally have slow growth rates and are resistant to chemotherapy and/or radiotherapy. Thus, new treatment strategies targeting these pathways to control stem-cell replication, survival and differentiation are under development. Herein, we provide an update on the latest advances in the clinical development of such approaches, and discuss strategies for overcoming CSC-associated primary or acquired resistance to cancer treatment. Given the crosstalk between the different embryonic developmental signalling pathways, as well as other pathways, designing clinical trials that target CSCs with rational combinations of agents to inhibit possible compensatory escape mechanisms could be of particular importance. We also share our views on the future directions for targeting CSCs to advance the clinical development of these classes of agents.