Cyclin-dependent kinase 5 controls vasculogenic mimicry formation in non-small cell lung cancer via the FAK-AKT signaling pathway

Inhibition of PD-L1 expression in non-small cell lung cancer may reduce vasculogenic mimicry formation by inhibiting the epithelial mesenchymal transformation process

Non-small cell lung cancer (NSCLC) is a kind of highly malignant tumor. Studies have shown that Vasculogenic mimicry (VM) may be responsible for dismal prognosis in NSCLC. Immunotherapy with programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1) has significantly altered the treatment of assorted cancers, including NSCLC, but its role and mechanism in the formation of Vasculogenic mimicry (VM) in NSCLC remains unclear. This study aimed to investigate the role of the anti-PD-L1 antibody in the formation of VM in NSCLC and its possible mechanisms. The results showed that anti-PD-L1 antibody therapy could inhibit the growth of NSCLC-transplanted tumors and reduce the formation of VMs. In addition, this study found that anti-PD-L1 antibodies could increase the expression of the epithelial-mesenchymal transition (EMT) related factor E-cadherin. zinc finger E-box binding homeobox 1 (ZEB1) is an important transcription factor regulating EMT. Knocking down ZEB1 could significantly inhibit tumor growth, as well as the expression of VE-cadherin and mmp2, while remarkably increase the expression of E-cadherin. During this process, the formation of VM was inhibited by knowing down ZEB1 in both in vitro and in vivo experiments of the constructed ZEB1 knockdown stable transfected cell strains. Therefore, in this study, we found that anti-PD-L1 antibodies may reduce the formation of VMs by inhibiting the EMT process.

Doxazosin inhibits vasculogenic mimicry in human non‑small cell lung cancer through inhibition of the VEGF‑A/VE‑cadherin/mTOR/MMP pathway

Lung cancer is the leading cause of cancer-related death worldwide, and ~85% of lung cancers are non-small cell lung cancer (NSCLC), which has a low 5-year overall survival rate and high mortality. Several therapeutic strategies have been developed, such as targeted therapy, immuno-oncotherapy and combination therapy. However, the low survival rate indicates the urgent need for new NSCLC treatments. Vasculogenic mimicry (VM) is an endothelial cell-free tumor blood supply system of aggressive and metastatic tumor cells present during tumor neovascularization. VM is clinically responsible for tumor metastasis and resistance, and is correlated with poor prognosis in NSCLC, making it a potential therapeutic target. In the present study, A549 cells formed glycoprotein-rich lined tubular structures, and transcript levels of VM-related genes were markedly upregulated in VM-forming cells. Based on a drug repurposing strategy, it was demonstrated that doxazosin (an antihypertensive drug) displayed inhibitory activity on VM formation at non-cytotoxic concentrations. Doxazosin significantly reduced the levels of vascular endothelial growth factor A (VEGF-A) and matrix metalloproteinase-2 (MMP-2) in the cell media during VM formation. Further experiments revealed that the protein expression levels of VEGF-A and vascular endothelial-cadherin (VE-cadherin), which contribute to tumor aggressiveness and VM formation, were downregulated following doxazosin treatment. Moreover, the downstream signaling Ephrin type-A receptor 2 (EphA2)/AKT/mTOR/MMP/Laminin-5γ2 network was inhibited in response to doxazosin treatment. In conclusion, the present study demonstrated that doxazosin displayed anti-VM activity in an NSCLC cell model through the downregulation of VEGF-A and VE-cadherin levels, and the suppression of signaling pathways related to the receptor tyrosine kinase, EphA2, protein kinases, AKT and mTOR, and proteases, MMP-2 and MMP-9. These results support the add-on anti-VM effect of doxazosin as a potential agent against NSCLC.

Celecoxib Blocks Vasculogenic Mimicry via an Off-Target Effect to Radiosensitize Lung Cancer Cells: An Experimental Study

The resistance to radiotherapy in lung cancer can be attributed to vasculogenic mimicry (VM) to some extent. Celecoxib (CXB), a selective inhibitor of cyclooxygenase-2 (COX-2), is reported as a radiosensitizer in non-small cell lung cancer (NSCLC). However, whether CXB can regulate VM formation via an off-target effect to radiosensitize NSCLC remains unclear. This study aimed to elucidate the mechanism underlying the radiosensitizing effect of CXB on NSCLC, i.e., whether CXB can inhibit VM formation via binding to newly identified targets other than COX-2. CXB radiosensitivity assay was performed in BALB/c mice bearing H460 xenografts and C57 mice bearing Lewis lung cancer (LLC) xenografts, which were divided into the control, CXB, irradiation (IR) treatment, and IR plus CXB groups. VM formation was observed using 3D Matrigel, periodic acid solution (PAS) staining, and immunofluorescence staining. The potential off-targets of CXB were screened using Protein Data Bank (PDB) database, MGLTools 1.5.6, and AutoDock Vina 1.1.2 and confirmed by Western blotting, enzyme activity assay, and RNA interference in vitro experiments and by immunohistochemistry in vivo experiments. CXB treatment almost eliminated the enhancement of VM formation by IR in vitro and in vivo, partially due to COX-2 inhibition. Four potential off-targets were predicted by molecular docking. Among them, aminopeptidase N (APN) and integrin alpha-V (ITAV) were remarkably inhibited in protein expression and enzyme activity in vitro or in vivo, consistent with the remarkable reduction of VM formation in H460 xenografts in BALB/c mice. In conclusion, CXB dramatically blocked VM through inhibiting newly identified off-targets APN and ITAV, other than COX-2, then radiosensitizing NSCLC.

GSK2126458 has the potential to inhibit the proliferation of pancreatic cancer uncovered by bioinformatics analysis and pharmacological experiments

BACKGROUND

Pancreatic cancer is one of the most serious digestive malignancies. At present, there is an extreme lack of effective strategies in clinical treatment. The purpose of this study is to identify key genes and pathways in the development of pancreatic cancer and provide targets for the treatment of pancreatic cancer.

METHODS

GSE15471 and GSE62165 were used to screen differentially expressed genes by GEO2R tool. Hub genes prognostic potential assessed using the GEPIA and Kaplan-Meier plotter databases. The drug susceptibility data of pan-cancer cell lines is provided by The Genomics of Drug Sensitivity in Cancer Project (GDSC). Finally, the effects of PI3K-Akt signaling pathway inhibitors on cell viability of pancreatic cancer cells were detected by cell proliferation and invasion assays.

RESULTS

A total of 609 differentially expressed genes were screened and enriched in the focal adhesion, phagosome and PI3K-Akt signaling pathway. Of the 15 hub genes we found, four were primarily associated with the PI3K-Akt signaling pathway, including COL3A1, EGF, FN1 and ITGA2. GDSC analysis showed that mTOR inhibitors are very sensitive to pancreatic cancer cells with mutations in EWSR1.FLI1 and RNF43. Cell proliferation and invasion results showed that mTOR inhibitors (GSK2126458) can inhibit the proliferation of pancreatic cancer cells.

CONCLUSIONS

This study suggested that the PI3K-Akt signaling pathway may be a key pathway for pancreatic cancer, our study uncovered the potential therapeutic potential of GSK2126458, a specific mTOR inhibitor, for pancreatic cancer.

TRPS1 knockdown inhibits angiogenic vascular mimicry in human triple negative breast cancer cells

PURPOSE

Vascular mimicry (VM) tubules are lumen structures comprised of malignant tumor cells without the participation of endothelial cells. VM simulates blood vessel function in tumors to deliver a sufficient blood supply for proliferation, invasion, and metastasis of malignant tumors, thereby reducing the clinical effects of anti-angiogenic treatments. The elimination or prevention of malignant tumor VM development therefore represents an urgent research goal as a therapeutic strategy to and cut off nutrients required for tumor growth. The GATA transcription factor TRPS1 is abnormally up-regulated in breast cancer, osteosarcoma, prostate cancer, and other tumor tissues, and is instrumental in regulating cell proliferation, differentiation, and tissue growth and development.

METHODS

Here, we explored the effects of TRPS1 knockdown on VM and the proteins underlying its development in triple-negative breast cancer cell line MDA-MB-231.

RESULTS

We found that TRPS1 knockdown resulted in obvious inhibition of VM development. Fluorescence microscopy of F-actin and tubulin revealed that loss of TRPS1 function resulted in disruption of cytoskeleton and microtubule formation, respectively. In addition, TRPS1-suppressed cells exhibited reduced accumulation of VM-associated proteins EphA2, MMP-2, MMP-9, VEGF, and VE-cadherin. Moreover, it is interesting to know that the capacity for migration and invasion were limited in MDA-MB-231cells after TRPS1 knockdown and that the average number of VM tubules, their length, and number of intersections were also significantly decreased.

CONCLUSIONS

Based on our results, and in light of previous studies, we thus proposed that TRPS1 suppression negatively affects vascular mimicry possibly through reduced TRPS1-mediated transcriptional regulation of VM-related protein VEGF-A.

Knockdown of CDK5 down-regulates PD-L1 via the ubiquitination-proteasome pathway and improves antitumor immunity in lung adenocarcinoma

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Knockdown of CDK5 down-regulates PD-L1 in lung adenocarcinoma and improves tumor immunity.

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Interference of CDK5 leads to ubiquitination and degradation of PD-L1 protein.

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TRIM21 mediates the ubiquitination and degradation process of PD-L1.

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Combination of CDK5 disruption and anti-PD-L1 therapy has a stronger effect on inhibiting tumor formation, compared with CDK5 knockdown alone.

Although immunotherapy (anti-PD-1/PD-L1 antibodies) has been approved for clinical treatment of lung cancer, only a small proportion of patients respond to monotherapy. Hence, understanding the regulatory mechanism of PD-L1 is particularly important to identify optimal combinations. In this study, we found that inhibition of CDK5 induced by shRNA or CDK5 inhibitor leads to reduced expression of PD-L1 protein in human lung adenocarcinoma cells, while the mRNA level is not substantially altered. The PD-L1 protein degradation is mediated by E3 ligase TRIM21 via ubiquitination-proteasome pathway. Subsequently, we studied the function of CDK5/PD-L1 axis in LUAD. In vitro, the absence of CDK5 in mouse Lewis lung cancer cell (LLC) has no effect on cell proliferation. However, the attenuation of CDK5 or combined with anti-PD-L1 greatly suppresses tumor growth in LLC implanted mouse models in vivo. Disruption of CDK5 elicits a higher level of CD3⁺, CD4⁺ and CD8⁺ T cells in spleens and lower PD-1 expression in CD4⁺ and CD8⁺ T cells. Our findings highlight a role for CDK5 in promoting antitumor immunity, which provide a potential therapeutic target for combined immunotherapy in LUAD.

CDK5 Knockdown inhibits proliferation and induces apoptosis and Cell Cycle Arrest in Human Glioblastoma

Aims: Gliomas are the most common malignant brain neoplasms with high recurrence and lethality rates. Recently, studies have reported that cyclin-dependent kinase 5 (CDK5) is involved in tumorigenesis. Herein, we applied bioinformatics analysis to determine the clinical value of CDK5 in patients with glioma and examined the effects of CDK5 on glioblastoma cell proliferation, apoptosis, and cell cycle in vitro.

Methods: Gene expression profiles containing clinical data of low-grade glioma (LGG) and glioblastoma cohorts were obtained from The Cancer Genome Atlas database and analyzed to determine the association between CDK5 expression and glioma clinicopathological characteristics. Kaplan-Meier survival analysis was performed for prognosis analysis. Gene set enrichment analysis (GSEA) was used to identify the biological pathways involved in differential CDK5 expression. In vitro experiments were performed to explore the effects of CDK5 on glioma cell functions.

Results: CDK5 expression was substantially higher in glioblastoma than in LGG. GSEA showed that some metabolism-related pathways were associated with the high CDK5 expression phenotype. In vitro experiments showed that CDK5 knockdown impaired cell proliferation and colony formation ability, and induced apoptosis and cell cycle arrest.

Conclusion: CDK5 may act as a potential biomarker of glioma progression and a valid target for glioma therapy.

DHPAC, a novel microtubule depolymerizing agent, suppresses angiogenesis and vasculogenic mimicry formation of human non-small cell lung cancer

Angiogenesis and vasculogenic mimicry (VM) are the main causes of tumor metastasis and recurrence. In this study, we investigated the antiangiogenesis and anti-VM formation of a novel microtubule depolymerizing agent, DHPAC, as well as combretastatin A4 (CA4, a combretastatin derivate) in non-small-cell lung cancer (NSCLC), subsequently elucidating the underlying mechanisms. In human umbilical vein endothelial cells (HUVECs), DHPAC could enter cells and inhibit proliferation, migration, and angiogenesis in the presence and absence of conditioned medium from H1299 cells. Interestingly, the inhibition was enhanced under the stimulation of the conditioned medium. Under hypoxia or normoxia, DHPAC suppressed signal transducer and activator of transcription 3 phosphorylation and reduced vascular endothelial growth factor (VEGF) expression and secretion from HUVECs, thus impeding the activation of the downstream signal transduction pathway of VEGF/VEGFR2. However, JNK inhibitors reversed the inhibitory effect of DHPAC on the angiogenesis, suggesting that DHPAC regulated angiogenesis through activating JNK. In H1299 cells, DHPAC could inhibit proliferation, migration, invasion, and the formation of VM. In addition, DHPAC inhibited the phosphorylation of FAK and AKT and decreased the expressions of VEGF, matrix metalloproteinase 2 (MMP2), MMP9 and Laminin 5, suggesting that DHPAC inhibited VM formation via the FAK/AKT signaling pathway. In addition, CA4 showed a similar effect as DHPAC against angiogenesis and VM formation. These new findings support the use of microtubule destabilizing agents as a promising strategy for cancer therapy.

Cell-dependent regulation of vasculogenic mimicry by carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1)

Vasculogenic mimicry (VM) promotes tumor migration, metastasis, and invasion in various types of cancer, but the relationship between VM and these phenotypes remains undefined. In this study, we examined carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) as a novel target of VM. We found that ectopic expression of CEACAM1 in HT1080 human fibrosarcoma cells suppressed the formation of a VM-like network. Further, cell migration and proliferation were abated by the introduction of CEACAM1 into HT1080 cells. Conversely, knockout (KO) of the CEACAM1 gene in SK-MEL-28 melanoma cells, which normally express high levels of CEACAM1, inhibited formation of a VM-like network, which was covered on reintroduction of CEACAM1. These results suggest that CEACAM1 differentially regulates formation of the VM-like network between cancer cell types and implicate CEACAM1 as a novel therapeutic target in malignant cancer.

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CEACAM1 is not expressed in HT1080 cells, and overexpression of CEACAM1 in HT1080 cells suppresses vasculogenic mimicry.

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CEACAM1 is highly expressed in SK-MEL-28 cells, and deletion of CEACAM1 in SK-MEL-28 cells abolishes vasculogenic mimicry.

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CEACAM1 regulates vasculogenic mimicry in a cell-dependent manner.

Regulation Networks Driving Vasculogenic Mimicry in Solid Tumors

Vasculogenic mimicry (VM) is a mechanism whereby cancer cells form microvascular structures similar to three-dimensional channels to provide nutrients and oxygen to tumors. Unlike angiogenesis, VM is characterized by the development of new patterned three-dimensional vascular-like structures independent of endothelial cells. This phenomenon has been observed in many types of highly aggressive solid tumors. The presence of VM has also been associated with increased resistance to chemotherapy, low survival, and poor prognosis. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are non-coding RNAs that regulate gene expression at the post-transcriptional level through different pathways. In recent years, these tiny RNAs have been shown to be expressed aberrantly in different human malignancies, thus contributing to the hallmarks of cancer. In this context, miRNAs and lncRNAs can be excellent biomarkers for diagnosis, prognosis, and the prediction of response to therapy. In this review, we discuss the role that the tumor microenvironment and the epithelial-mesenchymal transition have in VM. We include an overview of the mechanisms of VM with examples of diverse types of tumors. Finally, we describe the regulation networks of lncRNAs-miRNAs and their clinical impact with the VM. Knowing the key genes that regulate and promote the development of VM in tumors with invasive, aggressive, and therapy-resistant phenotypes will facilitate the discovery of novel biomarker therapeutics against cancer as well as tools in the diagnosis and prognosis of patients.

Mechanistic insight of cyclin-dependent kinase 5 in modulating lung cancer growth

Lung harbors the growth of primary and secondary tumors. Even though numerous factors regulate the complex signal transduction and cytoskeletal remodeling toward the progression of lung cancer, cyclin-dependent kinase 5 (Cdk5), a previously known kinase in the central nervous system, has raised much attention in the recent years. Patients with aberrant Cdk5 expression also lead to poor survival. Cdk5 has already been employed in various cellular processes which shape the fate of cancer. In lung cancer, Cdk5 mainly regulates tumor suppressor genes, carcinogenesis, cytoskeletal remodeling, and immune checkpoints. Inhibiting Cdk5 by using drugs, siRNA or CRISP-Cas9 system has rendered crucial therapeutic advantage in the combat against lung cancer. Thus, the relation of Cdk5 to lung cancer needs to be addressed in detail. In this review, we will discuss various cellular events modulated by Cdk5 and we will go further into their underlying mechanism in lung cancer.

Molecular Mechanisms and Anticancer Therapeutic Strategies in Vasculogenic Mimicry

Vasculogenic mimicry (VM) is a vascular formation mechanism used by aggressive tumor cells. VM provides an alternative pathway for adequate blood perfusion and challenges the traditional angiogenesis mechanism that depends only on endothelial cells (ECs), as VM-forming tumor cells express a mixed endothelial/tumor phenotype. VM is closely correlated with tumor invasion, migration, and progression. Hence, anticancer therapeutic strategies targeting VM biogenesis are essential. It is widely acknowledged that the VM formation mechanism involves multiple pathways. The purpose of this review is to describe the potential molecular mechanisms related to different pathways and discuss the involvement of microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) in VM formation. Moreover, we discuss the significance of VM in clinical practice and present new anticancer therapeutic strategies that target VM.

Melittin Inhibits Hypoxia-Induced Vasculogenic Mimicry Formation and Epithelial-Mesenchymal Transition through Suppression of HIF-1α/Akt Pathway in Liver Cancer

In this study, we investigated whether melittin could suppress hypoxia-induced vasculogenic mimicry (VM) formation in liver cancer and explored the underlying mechanisms. Melittin significantly inhibited the proliferation of liver cancer cells with or without CoCl₂ presence. Melittin also significantly inhibited CoCl₂-induced migration, invasion, and VM formation of liver cancer cells. CoCl₂ treatment suppressed the expression of E-cadherin and elevated the expression of N-cadherin and Vimentin. Melittin reversed the changes in the protein and mRNA levels of these epithelial-mesenchymal transition (EMT) markers. CoCl₂-induced accumulation of HIF-1α increased the level of phosphorylated Akt and upregulated the expression of VEGF and MMP-2/9. Melittin decreased the HIF-1α level and thereby suppressed the levels of p-Akt, VEGF, and MMP-2/9. In addition, the inhibitor of PI3K/Akt also suppressed CoCl₂-induced EMT and liver cancer cells migration, and the activator of Akt, SC-79, partly blocked the effect of melittin on CoCl₂-induced EMT and liver cancer cells migration. In the xenograft tumor model in nude mice, melittin treatment significantly suppressed the tumor growth, VM formation, and HIF-1α expression in the tumor. In conclusion, this study indicates melittin may inhibit hypoxia-induced VM formation and EMT in liver cancer through inhibiting HIF-1α/Akt pathway.

The prognostic value of Tiam1 correlates with its roles in epithelial-mesenchymal transition progression and angiogenesis in lung adenocarcinoma

Background

Tiam1 has been identified as an oncogene and acts as an activator of GTPase Rac. Tiam1 was reported to be a promoter of cancer progression in various cancer types, while in lung adenocarcinoma, its mechanism of action is poorly understood.

Materials and Methods

Immunohistochemistry staining and Western blot assay were used to determine Tiam1 expression in lung adenocarcinoma tissues, and its association with prognosis was determined by statistical analysis. We depleted Tiam1 in both A549 and H1975 cancer cell lines. Carboxyfluorescein diacetate succinimidyl ester staining and colony formation assays were used to evaluate its impact on cell proliferation ability after depletion. Transwell migration assay and wound healing assays were performed to determine its impact on migration ability of both cell lines. Western blot assay and immunofluorescence staining were used to analyze the association between Tiam1 and epithelial-mesenchymal transition (EMT) progression. Tube formation assay and vasculogenic mimicry assay were used to show the impact of Tiam1 depletion on cancer angiogenesis.

Results

In this study, we demonstrated that Tiam1 overexpression in lung adenocarcinoma was significantly associated with advanced tumor grade and poor prognosis. In vitro assays indicated that Tiam1 depletion significantly inhibited cell proliferation, colony formation, and migration capacities in A549 and H1975 cells. Further investigations revealed that Tiam1 plays an important role in EMT program enhancement, angiogenesis, and accelerated tumor progression. Notably, Tiam1 depletion in cancer cells strongly inhibited human umbilical vein endothelial cell angiogenesis and vasculogenic mimicry capacities of both cancer cell lines.

Conclusion

Tiam1 overexpression is associated with lung adenocarcinoma progression and may indicate poor prognosis. Tiam1 accelerated tumor progression due to EMT and angiogenesis enhancement. Our data may provide a novel therapeutic target for lung adenocarcinoma.

Brucine Suppresses Vasculogenic Mimicry in Human Triple-Negative Breast Cancer Cell Line MDA-MB-231

Vasculogenic mimicry (VM) with the pattern of endothelial independent tubular structure formation lined by aggressive tumor cells mimics regular tumor blood vessels to ensure robust blood supply and correlates with the proliferation, invasion, metastasis, and poor prognosis of malignant tumors, which was demonstrated to be a major obstacle for resistance to antiangiogenesis therapy. Therefore, it is urgent to discover methods to abrogate the VM formation of tumors, which possesses important practical significance for improving tumor therapy. Brucine is a traditional medicinal herb extracted from seeds of Strychnos nux-vomica L. (Loganiaceae) exhibiting antitumor activity in a variety of cancer models. In the present study, the effect of brucine on vasculogenic mimicry and the related mechanism are to be investigated. We demonstrated that, in a triple-negative breast cancer cell line MDA-MB-231, brucine induced a dose-dependent inhibitory effect on cell proliferation along with apoptosis induction at higher concentrations. The further study showed that brucine inhibited cell migration and invasion with a dose-dependent manner. Our results for the first time indicated that brucine could disrupt F-actin cytoskeleton and microtubule structure, thereby impairing hallmarks of aggressive tumors, like migration, invasion, and holding a possibility of suppressing vasculogenic mimicry. Hence, the inhibitory effect of brucine on vasculogenic mimicry was further verified. The results illustrated that brucine significantly suppressed vasculogenic mimicry tube formation with a dose-dependent effect indicated by the change of the number of tubules, intersections, and mean length of tubules. The in-depth molecular mechanism of vasculogenic mimicry suppression induced by brucine was finally suggested. It was demonstrated that brucine inhibited vasculogenic mimicry which might be through the downregulation of erythropoietin-producing hepatocellular carcinoma-A2 and matrix metalloproteinase-2 and metalloproteinase-9.

Evaluation of the correlation of vasculogenic mimicry, Notch4, DLL4, and KAI1/CD82 in the prediction of metastasis and prognosis in non-small cell lung cancer

Vasculogenic mimicry (VM) is a new blood supply style in tumors and has long been treated as a useful factor in malignant tumor metastasis and prognosis. Notch4 (a marker of Notch signaling pathway receptors), DLL4 (a marker of Notch signaling pathway ligands) and KAI1/CD82 (a suppressor gene of tumor metastasis) are all effective predictive factors for tumor metastasis. In this study, we analyzed correlations among VM, Notch4, DLL4, and KAI1/CD82 in non-small cell lung cancer (NSCLC), and their respective associations with patients' clinicopathological parameters and survival rate in NSCLC.Positive rates of VM, Notch4, DLL4, and KAI1/CD82 in 189 whole NSCLC specimens were detected by histochemical and immunohistochemical staining. Moreover, patients' clinicopathological information was also collected.Positive rates of VM, Notch4, and DLL4 were significantly higher, and levels of KAI1/CD82 were significantly lower in NSCLC than in normal lung tissues. Positive rates of VM, Notch4, and DLL4 were positively associated with tumor size, lymph node metastasis (LNM), distant metastasis (DM) and tumor-node-metastasis (TNM) stage, and inversely with patients, overall survival (OS) time and positive rate of DLL4 were positively associated with tumor grade. Levels of KAI1/CD82 were negatively associated with tumor size, LNM, DM, and TNM stage. The KAI1/CD82+ subgroup had significantly longer OS time than did the KAI1/CD82- subgroup. In multivariate analysis, high VM, Notch4, DLL4 levels, tumor size, LNM, DM, TNM stage, and low KAI1/CD82 levels were potential to be independent prognostic factors for overall survival time (OST) in NSCLC patients.VM and the expression of Notch4, DLL4, and KAI1/CD82 represent promising markers for tumor metastasis and prognosis, and maybe potential therapeutic targets for NSCLC.

CDK5 Functions as a Tumor Promoter in Human Lung Cancer

Cyclin-dependent kinase 5 (CDK5), an atypical member of the cyclin-dependent kinase family, plays an important role in the nervous system. Recent studies have shown that CDK5 is also associated with tumors. However, few studies have been done to investigate the mechanism underlying the connection between CDK5 and cancers. To explore the role of CDK5 in cancers by using an extensive bioinformatics data mining process. We mined the transcriptional, survival, functions and structure of CDK5 gene through databases and in vitro experiments. We found that higher CDK5 expression levels in most cancer cell lines while lower expression in liver and brain cancer cell lines. High expression of CDK5 was associated with shorter overall survival (OS) in lung cancer. In addition, high expression level of CDK5 promoted lung cancer cells proliferation and metastasis. Inhibited CDK5 decreases CAP1 phosphorylation. CDK5 may prove to be a valid target of anticancer therapies.

How Selective Are Pharmacological Inhibitors of Cell-Cycle-Regulating Cyclin-Dependent Kinases?

Cyclin-dependent kinases (CDKs) are an important and emerging class of drug targets for which many small-molecule inhibitors have been developed. However, there is often insufficient data available on the selectivity of CDK inhibitors (CDKi) to attribute the effects on the presumed target CDK to these inhibitors. Here, we highlight discrepancies between the kinase selectivity of CDKi and the phenotype exhibited; we evaluated 31 CDKi (claimed to target CDK1-4) for activity toward CDKs 1, 2, 4, 5, 7, 9 and for effects on the cell cycle. Our results suggest that most CDKi should be reclassified as pan-selective and should not be used as a tool. In addition, some compounds did not even inhibit CDKs as their primary cellular targets; for example, NU6140 showed potent inhibition of Aurora kinases. We also established an online database of commercially available CDKi for critical evaluation of their utility as molecular probes. Our results should help researchers select the most relevant chemical tools for their specific applications.

Bioinformatics analysis of microarray profiling identifies the mechanism of focal adhesion kinase signalling pathway in proliferation and apoptosis of breast cancer cells modulated by green tea polyphenol epigallocatechin 3-gallate

OBJECTIVES

This study aimed to investigate potential gene and signal pathway associated with tumour progression.

METHODS

Related microarray data set of breast cancer was obtained from Gene Expression Omnibus database, and differential-expressed genes (DEGs) between two control samples and two treated samples were analysed using statistical software R. We collected 50 epigallocatechin-3-gallate(EGCG)-related genes and 119 breast cancer-related genes to create a knowledge base for following pathway analysis.

KEY FINDINGS

A total of 502 mRNAs were identified as DEGs based on microarray analysis. Upregulated DEGs mainly enriched in nuclear nucleosome, cell adhesion, DNA packaging complex, Wnt-activated receptor activity, etc., while the downregulated DEGs significantly enriched in ncRNA processing, mitotic nuclear division, DNA helicase activity, etc. DEGs mostly enriched in gap junction, cell cycle, oxidative phosphorylation, focal adhesion, etc. EGCG suppressed FAK signalling pathway. Furthermore, EGCG could inhibit breast cancer cell proliferation and promote apoptosis by modulating CCND1.

CONCLUSIONS

Epigallocatechin 3-gallate might exert influence on breast cancer progression through inhibiting focal adhesion kinase (FAK) signalling pathway.

Recent advances in CDK inhibitors for cancer therapy

Inhibition of CDKs is an attractive approach to cancer therapy due to their vital role in cell growth and transcription. Pan-CDK inhibitors have shown some clinical benefit, and trials are ongoing. Selective CDK4 and CDK6 inhibitors have been licensed for the treatment of hormone responsive, RB-positive breast cancer in combination with antihormonal agents. Selective inhibitors of CDKs 5, 7, 8, 9 and 12 have been identified across a range of chemotypes.