Elucidating the mechanism of regulation of transforming growth factor β Type II receptor expression in human lung cancer cell lines

Therapeutic targeting of TGF-β in lung cancer

Transforming growth factor-β (TGF-β) plays a complex role in lung cancer pathophysiology, initially acting as a tumor suppressor by inhibiting early-stage tumor growth. However, its role evolves in the advanced stages of the disease, where it contributes to tumor progression not by directly promoting cell proliferation but by enhancing epithelial-mesenchymal transition (EMT) and creating a conducive tumor microenvironment. While EMT is typically associated with enhanced migratory and invasive capabilities rather than proliferation per se, TGF-β's influence on this process facilitates the complex dynamics of tumor metastasis. Additionally, TGF-β impacts the tumor microenvironment by interacting with immune cells, a process influenced by genetic and epigenetic changes within tumor cells. This interaction highlights its role in immune evasion and chemoresistance, further complicating lung cancer therapy. This review provides a critical overview of recent findings on TGF-β's involvement in lung cancer, its contribution to chemoresistance, and its modulation of the immune response. Despite the considerable challenges encountered in clinical trials and the development of new treatments targeting the TGF-β pathway, this review highlights the necessity for continued, in-depth investigation into the roles of TGF-β. A deeper comprehension of these roles may lead to novel, targeted therapies for lung cancer. Despite the intricate behavior of TGF-β signaling in tumors and previous challenges, further research could yield innovative treatment strategies.

circKCNN2 suppresses the recurrence of hepatocellular carcinoma at least partially via regulating miR-520c-3p/methyl-DNA-binding domain protein 2 axis

BACKGROUND

Recurrence is the major cause of hepatocellular carcinoma (HCC) death. We aimed to identify circular RNA (circRNA) with predictive and therapeutic value for recurrent HCC.

METHODS

Tissue samples from recurrent and non-recurrent HCC patients were subjected to circRNA sequencing and transcriptome sequencing. circKCNN2 was identified through multi-omics analyses. The effects of circKCNN2 on HCC were evaluated in cells, animals, database of The Cancer Genome Atlas, and a cohort with 130 HCC patients. circRNA precipitation, chromatin immunoprecipitation assay, RNA pull-down, luciferase assay, and cell experiments were applied to evaluate the interaction of circKCNN2 with miRNAs and proteins. The association between circKCNN2 and the therapeutic effect of lenvatinib was investigated in HCC cell lines and HCC tissue-derived organoids.

RESULTS

The expression of circKCNN2 was downregulated in HCC tissues and predicted a favorable overall survival and recurrence-free survival. The expression of circKCNN2 was positively correlated with the parental gene, potassium calcium-activated channel subfamily N member (KCNN2). Nuclear transcription factor Y subunit alpha (NFYA) was proven to inhibit the promoter activity of KCNN2, downregulate the expression of KCNN2 and circKCNN2, and predict an unfavorable recurrence-free survival. Ectopic expression of circKCNN2 inhibited HCC cell proliferation, colony formation, migration, and tumor formation in a mouse model. miR-520c-3p sponged by circKCNN2 could reverse the inhibitory effect of circKCNN2 on HCC cells and down-regulate the expression of methyl-DNA-binding domain protein 2 (MBD2). The intratumoral expression of MBD2 predicted a favorable recurrence-free survival. circKCNN2 down-regulated the expression of fibroblast growth factor receptor 4 (FGFR4), which can be reversed by miR-520c-3p and knockdown of MBD2. Lenvatinib inhibited the expression of FGFR4 and upregulated the expression of circKCNN2 and MBD2. Ectopic expression of circKCNN2 in HCC cells enhanced the therapeutic effect of lenvatinib. However, the high inherent level of circKCNN2 in HCC cells was associated with lenvatinib resistance.

CONCLUSIONS

circKCNN2, transcriptionally repressed by NFYA, suppresses HCC recurrence via the miR-520c-3p/MBD2 axis. Inherent level of circKCNN2 in HCC cells predisposes anti-tumor effect of lenvatinib possibly because both circKCNN2 and lenvatinib repress the expression of FGFR4. circKCNN2 may be a promising predictive biomarker and therapeutic agent for HCC recurrence.

Histone Modification in NSCLC: Molecular Mechanisms and Therapeutic Targets

Lung cancer is the leading cause of cancer mortality in both genders, with non-small cell lung cancer (NSCLC) accounting for about 85% of all lung cancers. At the time of diagnosis, the tumour is usually locally advanced or metastatic, shaping a poor disease outcome. NSCLC includes adenocarcinoma, squamous cell carcinoma, and large cell lung carcinoma. Searching for novel therapeutic targets is mandated due to the modest effect of platinum-based therapy as well as the targeted therapies developed in the last decade. The latter is mainly due to the lack of mutation detection in around half of all NSCLC cases. New therapeutic modalities are also required to enhance the effect of immunotherapy in NSCLC. Identifying the molecular signature of NSCLC subtypes, including genetics and epigenetic variation, is crucial for selecting the appropriate therapy or combination of therapies. Epigenetic dysregulation has a key role in the tumourigenicity, tumour heterogeneity, and tumour resistance to conventional anti-cancer therapy. Epigenomic modulation is a potential therapeutic strategy in NSCLC that was suggested a long time ago and recently starting to attract further attention. Histone acetylation and deacetylation are the most frequently studied patterns of epigenetic modification. Several histone deacetylase (HDAC) inhibitors (HDIs), such as vorinostat and panobinostat, have shown promise in preclinical and clinical investigations on NSCLC. However, further research on HDIs in NSCLC is needed to assess their anti-tumour impact. Another modification, histone methylation, is one of the most well recognized patterns of histone modification. It can either promote or inhibit transcription at different gene loci, thus playing a rather complex role in lung cancer. Some histone methylation modifiers have demonstrated altered activities, suggesting their oncogenic or tumour-suppressive roles. In this review, patterns of histone modifications in NSCLC will be discussed, focusing on the molecular mechanisms of epigenetic modifications in tumour progression and metastasis, as well as in developing drug resistance. Then, we will explore the therapeutic targets emerging from studying the NSCLC epigenome, referring to the completed and ongoing clinical trials on those medications.

Identification of novel biomarkers of prostate cancer through integrated analysis

Background

The current methods adopted to screen for prostate cancer (PCa) can sometimes be misleading and inaccurate. Moreover, for advanced stages of PCa, the current effect of treatment is not satisfactory for some patients. Accordingly, we aimed to identify new biomarkers for the diagnosis and prognosis of PCa.

Methods

A series of bioinformatic tools were utilized to search for potential new biomarkers of PCa and analyze their functions, expression, clinical relevance, prognostic value, and underlying mechanisms.

Results

Although ASPN was overexpressed in PCa, EDN3, PENK, MEIS2, IGF1, and CXCL12 were downregulated. The univariate Cox regression analysis showed that abnormally high expression of ASPN and low expression of other genes predicted worse prognosis. Moreover, the multivariate Cox regression analysis showed that ASPN, PENK, and MEIS2 were independently associated with the overall survival (OS) of patients, whereas other markers were not. The outcomes of gene ontology and gene set enrichment analysis showed that the expression levels of these genes might be associated with cell proliferation and infiltration of immune cells in PCa.

Conclusions

We demonstrated that ASPN, EDN3, PENK, MEIS2, IGF1, and CXCL12 are possibly novel diagnostic indicators for PCa, whereas ASPN, PENK, and MEIS2 show appealing potential to predict the prognosis of this disease.

Pan-RAS inhibitors: Hitting multiple RAS isozymes with one stone

Mutations in the three RAS oncogenes are present in approximately 30% of all human cancers that drive tumor growth and metastasis by aberrant activation of RAS-mediated signaling. Despite the well-established role of RAS in tumorigenesis, past efforts to develop small molecule inhibitors have failed for various reasons leading many to consider RAS as "undruggable." Advances over the past decade with KRAS(G12C) mutation-specific inhibitors have culminated in the first FDA-approved RAS drug, sotorasib. However, the patient population that stands to benefit from KRAS(G12C) inhibitors is inherently limited to those patients harboring KRAS(G12C) mutations. Additionally, both intrinsic and acquired mechanisms of resistance have been reported that indicate allele-specificity may afford disadvantages. For example, the compensatory activation of uninhibited wild-type (WT) NRAS and HRAS isozymes can rescue cancer cells harboring KRAS(G12C) mutations from allele-specific inhibition or the occurrence of other mutations in KRAS. It is therefore prudent to consider alternative drug discovery strategies that may overcome these potential limitations. One such approach is pan-RAS inhibition, whereby all RAS isozymes co-expressed in the tumor cell population are targeted by a single inhibitor to block constitutively activated RAS regardless of the underlying mutation. This chapter provides a review of past and ongoing strategies to develop pan-RAS inhibitors in detail and seeks to outline the trajectory of this promising strategy of RAS inhibition.

Effect of myeloid ecotropic viral integration site (MEIS) family genes on tumor microenvironment remodeling and its potential therapeutic effect

BACKGROUND

The myeloid ecotropic viral integration site (MEIS) family of genes is related to the occurrence, development, and outcome of many cancers. However, its role in the immune and tumor microenvironment (TME) is unclear. This study explored the relationship between the expression of MEIS genes and patient survival, immune subtypes, TME, tumor stem cell correlation, and drug sensitivity in cancer.

METHODS

We used The Cancer Genome Atlas pan-cancer data to analyze the expression of the MEIS family genes. Kaplan-Meier analysis and univariate Cox proportional hazard regression model were used to detect the relationship between gene expression and overall survival. Analysis of variance was used to explore the relationship between the MEIS family and the immune components in the tumor, and the ESTIMATE algorithm was used to calculate the proportion and level of tumor-infiltrating immune cells. Spearman and Pearson's correlation tests were carried out to detect the relationship between MEIS and the characteristics of tumor stem cells and drug sensitivity.

RESULTS

The MEIS family of genes shows different expression profiles in different cancers, with substantial inter- and intra-cancer heterogeneity. Among them, MEIS3 was upregulated in most cancers, whereas MEIS2 was downregulated. The change in MEIS gene expression was usually related to overall survival, but whether a member of the MEIS family was a risk factor or a protective factor was cancer-dependent. Immune component analysis suggested that the role of MEIS genes in promoting or inhibiting cancer may be related to different degrees of immune silencing. Further, there were varying degrees of correlation between MEIS gene expression and cancer cell stemness characteristics. It was also found that MEIS genes, especially MEIS1 and MEIS2, may be related to chemotherapy resistance.

CONCLUSIONS

We explored the expression, prognostic relationship, molecular characteristics, and effects on immunity and TME of the MEIS gene family in cancer. Our results suggest that MEIS members should be studied as independent entities in different types of cancer. The MEIS gene family may be a potential target for cancer therapy, but further experiments are needed to confirm this.

GATA2 regulates mast cell identity and responsiveness to antigenic stimulation by promoting chromatin remodeling at super-enhancers

Mast cells are critical effectors of allergic inflammation and protection against parasitic infections. We previously demonstrated that transcription factors GATA2 and MITF are the mast cell lineage-determining factors. However, it is unclear whether these lineage-determining factors regulate chromatin accessibility at mast cell enhancer regions. In this study, we demonstrate that GATA2 promotes chromatin accessibility at the super-enhancers of mast cell identity genes and primes both typical and super-enhancers at genes that respond to antigenic stimulation. We find that the number and densities of GATA2- but not MITF-bound sites at the super-enhancers are several folds higher than that at the typical enhancers. Our studies reveal that GATA2 promotes robust gene transcription to maintain mast cell identity and respond to antigenic stimulation by binding to super-enhancer regions with dense GATA2 binding sites available at key mast cell genes.

HDAC10 Regulates Cancer Stem-Like Cell Properties in KRAS-Driven Lung Adenocarcinoma

Activation of oncogenic KRAS is the most common driving event in lung adenocarcinoma development. Despite the existing rationale for targeting activated KRAS and its downstream effectors, the failure of clinical trials to date indicates that the mechanism of KRAS-driven malignancy remains poorly understood. Here we report that histone deacetylase 10 (HDAC10) might function as a putative tumor suppressor in mice carrying a spontaneously activated oncogenic Kras allele. Hdac10 deletion accelerated KRAS-driven early-onset lung adenocarcinomas, increased macrophage infiltration in the tumor microenvironment, and shortened survival time in mice. Highly tumorigenic and stem-like lung adenocarcinoma cells were increased in Hdac10-deleted tumors compared with Hdac10 wild-type tumors. HDAC10 regulated the stem-like properties of KRAS-expressing tumor cells by targeting SOX9. Expression of SOX9 was significantly increased in Hdac10-deleted tumor cells and depletion of SOX9 in Hdac10 knockout (KO) lung adenocarcinoma cells inhibited growth of tumorspheres. The genes associated with TGFβ pathway were enriched in Hdac10 KO tumor cells, and activation of TGFβ signaling contributed to SOX9 induction in Hdac10 KO lung adenocarcinoma cells. Overall, our study evaluates the functions and mechanisms of action of HDAC10 in lung carcinogenesis that will inform the rationale for targeting its related regulatory signaling as an anticancer strategy. SIGNIFICANCE: These findings linking HDAC10 and lung tumorigenesis identify potential novel strategies for targeting HDAC10 as a treatment for lung cancer.

MEIS transcription factors in development and disease

MEIS transcription factors are key regulators of embryonic development and cancer. Research on MEIS genes in the embryo and in stem cell systems has revealed novel and surprising mechanisms by which these proteins control gene expression. This Primer summarizes recent findings about MEIS protein activity and regulation in development, and discusses new insights into the role of MEIS genes in disease, focusing on the pathogenesis of solid cancers.

The homeobox transcription factor MEIS2 is a regulator of cancer cell survival and IMiDs activity in Multiple Myeloma: modulation by Bromodomain and Extra-Terminal (BET) protein inhibitors

The transcription factor Myeloid Ecotropic Insertion Site 2 (MEIS2) has been identified as a cellular substrate of the E3-ubiquitin ligase complex CRL4-cereblon (^CRL4CRBN) in crystal structure and by biochemical screen. Emerging evidence suggests that IMiDs can block MEIS2 from binding to CRBN facilitating the subsequent activation of a ^CRL4CRBN^IMiD-E3-ubiquitin ligase activity and proteasome-mediated degradation of critical substrates regulators of Multiple Myeloma (MM) cell survival and proliferation. Bromodomain and Extra-Terminal (BET) family of proteins are important epigenetic regulators involved in promoting gene expression of several oncogenes, and many studies have revealed important anticancer activities mediated by BET inhibitors (BETi) in hematologic malignancies including MM. Here, we investigated MEIS2 in MM, the role of this protein as a modulator of IMiDs activity and the ability of BETi to inhibit its expression. Our observations indicate that inhibition of MEIS2 in MM cells by RNA interference correlates with reduced growth, induction of apoptosis and enhanced efficacy of different anti-MM drugs. In addition, MEIS2 regulates the expression of Cyclin E/CCNE1 in MM and induction of apoptosis after treatment with the CDK inhibitor Seliciclib/Roscovitine. Interestingly, modulation of MEIS2 can regulate the expression of NKG2D and DNAM-1 NK cell-activating ligands and, importantly, the activity of IMiDs in MM cells. Finally, BETi have the ability to inhibit the expression of MEIS2 in MM, underscoring a novel anticancer activity mediated by these drugs. Our study provides evidence on the role of MEIS2 in MM cell survival and suggests therapeutic strategies targeting of MEIS2 to enhance IMiDs anti-myeloma activity.

Ras enhances TGF-β signaling by decreasing cellular protein levels of its type II receptor negative regulator SPSB1

Background

Transformation by oncogene Ras overcomes TGF-β mediated growth inhibition in epithelial cells. However, it cooperates with each other to mediate epithelial to mesenchymal transition (EMT). The mechanism of how these two pathways interact with each other is controversial.

Methods

Molecular techniques were used to engineer expression plasmids for Ras, SPRY, TGF-β receptors, type I and II and ubiquitin. Immunoprecipitation and western blots were employed to determine protein-protein interactions, preotein levels, protein phosphorylation while immunofluorecesent staining for molecular co-localization. TGF-β signalling activities is also determined by its luciferase reporter assay. Trans-well assays were used to measure cell migration and invasion.

Results

Ras interacts with the SPSB1’s SPRY domain to enhance TGF-β signaling. Ras interacts and colocalizes with the TGF-β type II receptor’s (TβRII) negative regulator SPSB1 on the cell membrane, consequently promoting SPSB1 protein degradation via enhanced mono- and di-ubiquitination. Reduced SPSB1 levels result in the stablization of TβRII, in turn the increase of receptor levels significantly enhance Smad2/3 phosphorylation and signaling. Importantly, forced expression of SPSB1 in Ras transformed cells suppresses TGF-β signaling and its mediated migration and invasion.

Conclusion

Ras positively cooperates with TGF-β signaling by reducing the cellular protein levels of TβRII negative regualtor SPSB1.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0223-4) contains supplementary material, which is available to authorized users.

Regulatory T cells and potential inmmunotherapeutic targets in lung cancer

Lung cancer and metastasis are two of the most lethal diseases globally and seldom have effective therapies. Immunotherapy is considered as one of the powerful alternatives. Regulatory T cells (Tregs) can suppress the activation of the immune system, maintain immune tolerance to self-antigens, and contribute to immunosuppression of antitumor immunity, which is critical for tumor immune evasion in epithelial malignancies, including lung cancer. The present review gives an overview of the biological functions and regulations of Tregs associated with the development of lung cancer and metastasis and explores the potentials of Treg-oriented therapeutic targets. Subsets and features of Tregs mainly include naturally occurring Tregs (nTregs) (CD4(+) nTregs and CD8(+) nTregs) and adaptive/induced Tregs (CD4(+) iTregs and CD8(+) iTregs). Tregs, especially in circulation or regional lymph nodes, play an important role in the progress and metastasis of lung cancer and are considered as therapeutic targets and biomarkers to predict the survival length and recurrence of lung cancer. Increasing understanding of Tregs' functional mechanisms will lead to a number of clinical trials on the discovery and development of Treg-oriented new therapies. Tregs play important roles in lung cancer and metastasis, and the understanding of Tregs becomes more critical for clinical applications and therapies. Thus, Tregs and associated factors can be potential therapeutic targets for lung cancer immunotherapy.

An epigenetic auto-feedback loop regulates TGF-β type II receptor expression and function in NSCLC

The downregulation of transforming growth factor-β (TGF-β) type II receptor (TβRII) expression and function plays a pivotal role in the loss of the TGF-β-induced tumor suppressor function that contributes to lung cancer progression. The aberrant expression of miRNAs has been shown to be involved in the regulation of oncogenes and tumor suppressor genes. Our current study involving miRNA microarray, northern blot and QRT-PCR analysis shows an inverse correlation between miR-20a and TβRII expression in non-small cell lung cancer (NSCLC) tissues and cell lines. Stable expression of miR-20a downregulates TβRII in lung epithelial cells which results in an inhibition of TGF-β signaling and attenuation of TGF-β-induced cell growth suppression and apoptosis. Stable knock down of miR-20a increases TβRII expression and inhibits tumorigenicity of lung cancer cells in vivo. Oncogene c-Myc promotes miR-20a expression by activating its promoter leading to downregulation of TβRII expression and TGF-ß signaling. MiR-145, which is upregulated by TGF-β, inhibits miR-20a expression by targeting c-Myc and upregulates TβRII expression. These correlations among miRNAs and cellular proteins are supported by TCGA public database using NSCLC specimens. These results suggest a novel mechanism for the loss of TβRII expression and TGF-β-induced tumor suppressor functions in lung cancer through a complex auto-feedback loop TGF-β/miR-145/c-Myc/miR-20a/TβRII.

IL-21 polymorphisms rs907715 and rs2221903 are associated with decreased non-small cell lung cancer susceptibility

The etiology of lung cancer is still incompletely understood. Previous studies have suggested the association between IL-21 polymorphisms and autoimmune diseases, however, little is known about its role in lung cancer susceptibility. Here, we investigated the role of two SNPs of IL-21 gene in a cohort of non-small cell lung cancer (NSCLC) patients. A total of 128 NSCLC patients and 156 healthy controls were genotyped. Multivariate logistic regression was used to analyze the association between IL-21 polymorphisms and NSCLC risk. Our data showed that both rs907715 and rs2221903 were significantly associated with lung cancer susceptibility, and patients carrying rs907715A (P = 0.007, adjusted OR = 0.60, 95% CI = 0.42-0.87) or rs2221903G (P = 0.020, adjusted OR = 0.52, 95% CI = 0.30-0.90) allele had a decreased risk of NSCLC. Further study identified that the association between IL-21 polymorphisms and NSCLC risk was limited to lung adenocarcinoma. Haplotype analysis revealed that the AG (P = 0.006, OR = 0.072 95% CI = 0.011-0.451) and AA (P = 0.022, OR = 0.657, 95% CI = 0.458-0.941) haplotypes of rs907715/rs2221903 were associated with a decreased risk of NSCLC, whereas the GA (P = 0.0001, OR = 1.932, 95% CI = 1.378-2.710) haplotype was associated with an increased risk. In conclusion, our study demonstrates the association between IL-21 polymorphisms (rs907715 and rs2221903) and NSCLC risk in a Chinese Han population, indicating their potential role in lung cancer detection and treatment.

Immunotherapy in lung cancer

Immunotherapy has emerged in recent years as a promising therapeutic approach in lung cancer. Two approaches are of particular interest: immune checkpoint inhibition, which aims to counteract the physiologic mechanisms of immune tolerance co-opted by some tumors, and vaccine therapy, which enables enhanced exposure to tumor antigen. Immune checkpoint therapies include the monoclonal antibody blockade of the cytotoxic T-lymphocyte antigen-4 (CTLA-4) with ipilimumab, as well as antibody blockade of the programmed cell death-1 (PD-1) receptor and the PD-1 ligand. These immune checkpoint therapies have been evaluated in both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) with early evidence of activity. Vaccines include antigen specific therapies which induce specific antitumor immunity against relevant tumor-associated antigens. In lung cancer, these include the melanoma-associated antigen-A3 (MAGE-A3), membrane-associated glycoprotein (MUC-1), and the epidermal growth factor receptor (EGFR). Whole tumor vaccines have also been evaluated in lung cancer and influence the patient's immune system to allow recognition of the tumor as foreign creating de novo immunity. This review summarizes the evidence to date for the efficacy and safety of immunotherapies in lung cancer.

A pan-cancer modular regulatory network analysis to identify common and cancer-specific network components

Many human diseases including cancer are the result of perturbations to transcriptional regulatory networks that control context-specific expression of genes. A comparative approach across multiple cancer types is a powerful approach to illuminate the common and specific network features of this family of diseases. Recent efforts from The Cancer Genome Atlas (TCGA) have generated large collections of functional genomic data sets for multiple types of cancers. An emerging challenge is to devise computational approaches that systematically compare these genomic data sets across different cancer types that identify common and cancer-specific network components. We present a module- and network-based characterization of transcriptional patterns in six different cancers being studied in TCGA: breast, colon, rectal, kidney, ovarian, and endometrial. Our approach uses a recently developed regulatory network reconstruction algorithm, modular regulatory network learning with per gene information (MERLIN), within a stability selection framework to predict regulators for individual genes and gene modules. Our module-based analysis identifies a common theme of immune system processes in each cancer study, with modules statistically enriched for immune response processes as well as targets of key immune response regulators from the interferon regulatory factor (IRF) and signal transducer and activator of transcription (STAT) families. Comparison of the inferred regulatory networks from each cancer type identified a core regulatory network that included genes involved in chromatin remodeling, cell cycle, and immune response. Regulatory network hubs included genes with known roles in specific cancer types as well as genes with potentially novel roles in different cancer types. Overall, our integrated module and network analysis recapitulated known themes in cancer biology and additionally revealed novel regulatory hubs that suggest a complex interplay of immune response, cell cycle, and chromatin remodeling across multiple cancers.

MEIS2 is essential for neuroblastoma cell survival and proliferation by transcriptional control of M-phase progression

MEIS2 has an important role in development and organogenesis, and is implicated in the pathogenesis of human cancer. The molecular basis of MEIS2 action in tumorigenesis is not clear. Here, we show that MEIS2 is highly expressed in human neuroblastoma cell lines and is required for neuroblastoma cell survival and proliferation. Depletion of MEIS2 in neuroblastoma cells leads to M-phase arrest and mitotic catastrophe, whereas ectopic expression of MEIS2 markedly enhances neuroblastoma cell proliferation, anchorage-independent growth, and tumorigenicity. Gene expression profiling reveals an essential role of MEIS2 in maintaining the expression of a large number of late cell-cycle genes, including those required for DNA replication, G2-M checkpoint control and M-phase progression. Importantly, we identify MEIS2 as a transcription activator of the MuvB-BMYB-FOXM1 complex that functions as a master regulator of cell-cycle gene expression. Further, we show that FOXM1 is a direct target gene of MEIS2 and is required for MEIS2 to upregulate mitotic genes. These findings link a developmentally important gene to the control of cell proliferation and suggest that high MEIS2 expression is a molecular mechanism for high expression of mitotic genes that is frequently observed in cancers of poor prognosis.

Cancer subclonal genetic architecture as a key to personalized medicine

The future of personalized oncological therapy will likely rely on evidence-based medicine to integrate all of the available evidence to delineate the most efficacious treatment option for the patient. To undertake evidence-based medicine through use of targeted therapy regimens, identification of the specific underlying causative mutation(s) driving growth and progression of a patient's tumor is imperative. Although molecular subtyping is important for planning and treatment, intraclonal genetic diversity has been recently highlighted as having significant implications for biopsy-based prognosis. Overall, delineation of the clonal architecture of a patient's cancer and how this will impact on the selection of the most efficacious therapy remain a topic of intense interest.

Vicious cycle of TGF-β signaling in tumor progression and metastasis

TGF-β is an important biological mediator. It regulates a wide range of functions including embryonic development, wound healing, organ development, immuno-modulation, and cancer progression. Interestingly, TGF-β is known to inhibit cell growth in benign cells but promote progression in cancer cells, a phenomenon known as TGF-β paradox. TGF-β stimulation in cancer cells leads to a differential Erk activation, which srves as the basis of TGF-β paradox between benign and cancer cells. The critical events of TGF-β mediated Erk activation are suppressed TBRs and elevated TGF-β in tumor cells but not in benign cells. These events form the basis of the "vicious cycle of TGF-β signaling". The term "vicious cycle", implies that, with each advancing cycle of TGF-β signaling, the tumor will accumulate more TGF-β and will be more "aggressive" than that of the previous cycle. Understanding this vicious cycle of TGF-β signaling in tumor progression and metastasis will help us to predict indolent from aggressive cancers and will help us to develop novel anti-cancer strategies.

Mysteries of TGF-β Paradox in Benign and Malignant Cells

TGF-β regulates a wide range of biological functions including embryonic development, wound healing, organogenesis, immune modulation, and cancer progression. Interestingly, TGF-β is known to inhibit cell growth in benign cells but promote progression in cancer cells; this phenomenon is known as TGF-β paradox. To date, the mechanism of this paradox still remains a scientific mystery. In this review, we present our experience, along with the literature, in an attempt to answer this mystery. First, we observed that, on TGF-β engagement, there is a differential activation of Erk between benign and cancer cells. Since activated Erk is a major mediator in tumor progression and metastasis, a differentially activated Erk represents the answer to this mystery. Second, we identified a key player, PP2A-B56α, which is differentially recruited by the activated type I TGF-β receptor (TBRI) in benign and tumor cells, resulting in differential Erk activation. Finally, TGF-β stimulation leads to suppressed TBRs in tumor cells but not in benign cells. This differentially suppressed TBRs triggers differential recruitment of PP2A-B56α and, thus, differential activation of Erk. The above three events explain the mysteries of TGF-β paradox. Understanding the mechanism of TGF-β paradox will help us to predict indolent from aggressive cancers and develop novel anti-cancer strategies.

Histone deacetylases: a saga of perturbed acetylation homeostasis in cancer

In the current era of genomic medicine, diseases are identified as manifestations of anomalous patterns of gene expression. Cancer is the principal example among such maladies. Although remarkable progress has been achieved in the understanding of the molecular mechanisms involved in the genesis and progression of cancer, its epigenetic regulation, particularly histone deacetylation, demands further studies. Histone deacetylases (HDACs) are one of the key players in the gene expression regulation network in cancer because of their repressive role on tumor suppressor genes. Higher expression and function of deacetylases disrupt the finely tuned acetylation homeostasis in both histone and non-histone target proteins. This brings about alterations in the genes implicated in the regulation of cell proliferation, differentiation, apoptosis and other cellular processes. Moreover, the reversible nature of epigenetic modulation by HDACs makes them attractive targets for cancer remedy. This review summarizes the current knowledge of HDACs in tumorigenesis and tumor progression as well as their contribution to the hallmarks of cancer. The present report also describes briefly various assays to detect histone deacetylase activity and discusses the potential role of histone deacetylase inhibitors as emerging epigenetic drugs to cure cancer.

Neuropilin-2 Is upregulated in lung cancer cells during TGF-β1-induced epithelial-mesenchymal transition

The epithelial-mesenchymal transition (EMT) and its reversal, mesenchymal-epithelial transition (MET), are fundamental processes involved in tumor cell invasion and metastasis. SEMA3F is a secreted semaphorin and tumor suppressor downregulated by TGF-β1 and ZEB1-induced EMT. Here, we report that neuropilin (NRP)-2, the high-affinity receptor for SEMA3F and a coreceptor for certain growth factors, is upregulated during TGF-β1-driven EMT in lung cancer cells. Mechanistically, NRP2 upregulation was TβRI dependent and SMAD independent, occurring mainly at a posttranscriptional level involving increased association of mRNA with polyribosomes. Extracellular signal-regulated kinase (ERK) and AKT inhibition blocked NRP2 upregulation, whereas RNA interference-mediated attenuation of ZEB1 reduced steady-state NRP2 levels. In addition, NRP2 attenuation inhibited TGF-β1-driven morphologic transformation, migration/invasion, ERK activation, growth suppression, and changes in gene expression. In a mouse xenograft model of lung cancer, NRP2 attenuation also inhibited locally invasive features of the tumor and reversed TGF-β1-mediated growth inhibition. In support of these results, human lung cancer specimens with the highest NRP2 expression were predominantly E-cadherin negative. Furthermore, the presence of NRP2 staining strengthened the association of E-cadherin loss with high-grade tumors. Together, our results demonstrate that NRP2 contributes significantly to TGF-β1-induced EMT in lung cancer.

Overcoming intratumor heterogeneity of polygenic cancer drug resistance with improved biomarker integration

Improvements in technology and resources are helping to advance our understanding of cancer-initiating events as well as factors involved with tumor progression, adaptation, and evasion of therapy. Tumors are well known to contain diverse cell populations and intratumor heterogeneity affords neoplasms with a diverse set of biologic characteristics that can be used to evolve and adapt. Intratumor heterogeneity has emerged as a major hindrance to improving cancer patient care. Polygenic cancer drug resistance necessitates reconsidering drug designs to include polypharmacology in pursuit of novel combinatorial agents having multitarget activity to overcome the diverse and compensatory signaling pathways in which cancer cells use to survive and evade therapy. Advances will require integration of different biomarkers such as genomics and imaging to provide for more adequate elucidation of the spatially varying location, type, and extent of diverse intratumor signaling molecules to provide for a rationale-based personalized cancer medicine strategy.

Emerging evidence of epithelial-to-mesenchymal transition in lung carcinogenesis

The epithelial-to-mesenchymal transition (EMT) is a developmental programme that regulates embryonic morphogenesis and involves significant morphological and molecular changes in cells. Experimental models have revealed that EMT also contributes to various malignant features of cancer cells, including motile, invasive, anti-apoptotic and stem-like phenotypes. Clinically, correlative studies have indicated that mesenchymal-like features of tumour cells are associated with poor tumour differentiation as well as worse patient prognosis. Nevertheless, due to its transitory nature, demonstration of an actual occurrence of EMT during human carcinogenesis is challenging, and most of the evidence to date has been limited to breast and colorectal cancers. However, recent studies suggest that EMT may occur during lung cancer development, although such evidence is still limited. We propose three approaches for obtaining direct evidence of EMT in human cancers and use these criteria to review the available data. We suggest that multiple intrinsic and extrinsic factors cooperatively induce EMT in lung cancer. Intrinsic factors include oncogenic genetic changes such as mutant K-RAS. Extrinsic factors are associated with a tumour microenvironment that is inflammatory and hypoxic. The induction of EMT is primarily mediated by various EMT-inducing transcription factors that suppress E-cadherin expression, including SLUG and ZEB1. miR-200 family expression can reverse EMT by suppressing EMT- inducing transcription factors. Obviously, more data demonstrating the clinical relevance of EMT in lung cancer are required, and further elucidation of how EMT is regulated in lung cancer will enable us to develop novel therapeutics that specifically target molecules with critical roles in EMT.

Role of TGF-β signaling in curcumin-mediated inhibition of tumorigenicity of human lung cancer cells

PURPOSE

Curcumin has been shown to have potent anticancer activities like inhibition of cell proliferation, induction of apoptosis, and suppression of angiogenesis. Transforming growth factor-β (TGF-β) signaling plays a complex role in tumor suppression and promotion depending on the tumor type and stage. However, the effect of curcumin on TGF-β signaling in cancer cells and the role of TGF-β signaling in curcumin-induced anticancer activities have not been determined. Here, we investigate the role of curcumin on TGF-β signaling, and whether TGF-β signaling is involved in the antitumor activities of curcumin.

METHODS

Human non-small cell lung cancer (NSCLC) cell lines, ACC-LC-176 (without TGF-β signaling), H358, and A549 (with TGF-β signaling) were treated with curcumin to determine cell growth, apoptosis, and tumorigenicity. Antitumor activities of curcumin were determined using these cell lines and an in vivo mouse model. We also tested the effect of curcumin on TGF-β/Smad signaling by western blotting and by luciferase assays.

RESULTS

Curcumin inhibited cell growth and induced apoptosis of all three NSCLC cell lines in vitro and in vivo. It significantly reduced subcutaneous tumor growth by these three cell lines irrespective of TGF-β signaling status. Curcumin inhibited TGF-β-induced Smad2/3 phosphorylation and transcription in H358 and A549 cells, but not in ACC-LC-176 cells.

CONCLUSIONS

Curcumin reduces tumorigenicity of human lung cancer cells in vitro and in vivo by inhibiting cell proliferation and promoting apoptosis. These results suggest that TGF-β signaling is not directly involved in curcumin-mediated growth inhibition, induction of apoptosis, and inhibition of tumorigenicity.

Genes regulated in metastatic osteosarcoma: evaluation by microarray analysis in four human and two mouse cell line systems

Osteosarcoma (OS) is a rare bone neoplasm that affects mainly adolescents. It is associated with poor prognosis in case of metastases formation. The search for metastasis predicting markers is therefore imperative to optimize treatment strategies for patients at risk and important for the search of new drugs for the treatment of this devastating disease. Here, we have analyzed by microarray the differential gene expression in four human and two mouse OS cell line systems consisting of parental cell lines with low metastatic potential and derivatives thereof with increased metastatic potential. Using two osteoblastic cell line systems, the most common OS phenotype, we have identified forty-eight common genes that are differentially expressed in metastatic cell lines compared to parental cells. The identified subset of metastasis relevant genes in osteoblastic OS overlapped only minimally with differentially expressed genes in the other four preosteoblast or nonosteoblastic cell line systems. The results imply an OS phenotype specific expression pattern of metastasis regulating proteins and form a basis for further investigation of gene expression profiles in patients' samples combined with survival analysis with the aim to optimize treatment strategies to develop new drugs and to consequently improve the survival of patients with the most common form of osteoblastic OS.

The significance of epigenetic alterations in lung carcinogenesis

Lung cancer is recognized as a leading cause of cancer-related death worldwide and its frequency is still increasing. The prognosis in lung cancer is poor and limited by the difficulties of diagnosis at early stage of disease, when it is amenable to surgery treatment. Therefore, the advance in identification of lung cancer genetic and epigenetic markers with diagnostic and/or prognostic values becomes an important tool for future molecular oncology and personalized therapy. As in case of other tumors, aberrant epigenetic landscape has been documented also in lung cancer, both at early and late stage of carcinogenesis. Hypermethylation of specific genes, mainly tumor suppressor genes, as well as hypomethylation of oncogenes and retrotransposons, associated with histopathological subtypes of lung cancer, has been found. Epigenetic aberrations of histone proteins and, especially, the lower global levels of histone modifications have been associated with poorer clinical outcome in lung cancer. The recently discovered role of epigenetic modifications of microRNA expression in tumors has been also proven in lung carcinogenesis. The identified epigenetic events in lung cancer contribute to its specific epigenotype and correlated phenotypic features. So far, some of them have been suggested to be cancer biomarkers for early detection, disease monitoring, prognosis, and risk assessment. As epigenetic aberrations are reversible, their correction has emerged as a promising therapeutic target.

Immune alterations and emerging immunotherapeutic approaches in lung cancer

INTRODUCTION

Subjects with lung cancer were shown to present a variety of immune abnormalities including cellular immune dysfunction, cytokine alterations, and antigen presentation defects. As discouraging results are commonly seen with the existing therapies in lung cancer, more innovative treatment strategies are needed.

AREAS COVERED

The authors review comprehensively the immune abnormalities in individuals with lung cancer, describe the lung cancer immunotherapy candidates that are most advanced in their clinical development, and summarize recent data from clinical trials of these agents.

EXPERT OPINION

Enhancing the immune system represents an appealing avenue for lung cancer therapy. Several immunomodulating agents have activity in this regard including ipilimumab, a monoclonal antibody against the CTLA-4, and talactoferrin, a dendritic cell activator. In addition, a significant activity was shown with belagenpumatucel-L, a whole-cell-based vaccine that blocks the action of TGF-β2. Other promising vaccines are protein-specific vaccines against tumor antigens such as MAGE-A3, EGF, and MUC1. Although some of these immunotherapies may have lackluster performance as single agents in advanced disease, more impressive results are seen in combination with chemotherapy agents. Given their proven activity in lung cancer, these immunotherapies may soon become a powerful addition to the oncologist's toolbox.

The interconnectedness of cancer cell signaling

The elegance of fundamental and applied research activities have begun to reveal a myriad of spatial and temporal alterations in downstream signaling networks affected by cell surface receptor stimulation including G protein-coupled receptors and receptor tyrosine kinases. Interconnected biochemical pathways serve to integrate and distribute the signaling information throughout the cell by orchestration of complex biochemical circuits consisting of protein interactions and covalent modification processes. It is clear that scientific literature summarizing results from both fundamental and applied scientific research activities has served to provide a broad foundational biologic database that has been instrumental in advancing our continued understanding of underlying cancer biology. This article reflects on historical advances and the role of innovation in the competitive world of grant-sponsored research.