Methylated +58CpG site decreases DCN mRNA expression and enhances TGF-β/Smad signaling in NSCLC cells with high metastatic potential

Role of Ubiquitination and Epigenetics in the Regulation of AhR Signaling in Carcinogenesis and Metastasis: "Albatross around the Neck" or "Blessing in Disguise"

The molecular mechanisms and signal transduction cascades evoked by the activation of aryl hydrocarbon receptor (AhR) are becoming increasingly understandable. AhR is a ligand-activated transcriptional factor that integrates environmental, dietary and metabolic cues for the pleiotropic regulation of a wide variety of mechanisms. AhR mediates transcriptional programming in a ligand-specific, context-specific and cell-type-specific manner. Pioneering cutting-edge research works have provided fascinating new insights into the mechanistic role of AhR-driven downstream signaling in a wide variety of cancers. AhR ligands derived from food, environmental contaminants and intestinal microbiota strategically activated AhR signaling and regulated multiple stages of cancer. Although AhR has classically been viewed and characterized as a ligand-regulated transcriptional factor, its role as a ubiquitin ligase is fascinating. Accordingly, recent evidence has paradigmatically shifted our understanding and urged researchers to drill down deep into these novel and clinically valuable facets of AhR biology. Our rapidly increasing realization related to AhR-mediated regulation of the ubiquitination and proteasomal degradation of different proteins has started to scratch the surface of intriguing mechanisms. Furthermore, AhR and epigenome dynamics have shown previously unprecedented complexity during multiple stages of cancer progression. AhR not only transcriptionally regulated epigenetic-associated molecules, but also worked with epigenetic-modifying enzymes during cancer progression. In this review, we have summarized the findings obtained not only from cell-culture studies, but also from animal models. Different clinical trials are currently being conducted using AhR inhibitors and PD-1 inhibitors (Pembrolizumab and nivolumab), which confirm the linchpin role of AhR-related mechanistic details in cancer progression. Therefore, further studies are required to develop a better comprehension of the many-sided and "diametrically opposed" roles of AhR in the regulation of carcinogenesis and metastatic spread of cancer cells to the secondary organs.

Prognostic Hub Genes in the Immune Microenvironment of Lung Adenocarcinoma by Estimation

BACKGROUND

The mortality of lung adenocarcinoma(LUAD) is high. Recent studies have found that the degree of immune infiltration and stromal cells in the tumour microenvironment or tumours makes a significant contribution to prognosis.

METHODS

During study, we screened differentially expressed genes (DEGs) of TCGA database for prognostic genes in LUAD immune microenvironment. Further, immune and stromal cells were quantified using ESTIMATE algorithm. To study the effects of immune and stromal cell-associated genes on the prognosis of LUAD, LUAD patients were divided into high and low groups according to their immune/ stromal scores. The obtained scores were found to be related to the phenotype and survival rate of LUAD patients. By selecting DEGs with high expression in immune and stromal cells, we performed functional enrichment analysis and found that most genes are associated with pathways of cancer, stimulus response and the MAPK signaling. The functions and enriched pathways of LUAD prognostic genes were shown by a protein-protein interaction (PPI) network. Nonetheless, an external database was used to validate the prognostic genes from the TCGA.

RESULTS

Prognostic genes were listed according to their expression position and protein function.

CONCLUSION

We provided a new targets for immunotherapy of LUAD, which further provides basic knowledge for future clinical research.

Decorin inhibits the insulin-like growth factor I signaling in bone marrow mesenchymal stem cells of aged humans

Aging impairs the IGF-I signaling of bone marrow mesenchymal stem cells (bmMSCs), but the mechanism is unclear. Here, we found that the ability to auto-phosphorylate IGF-I receptor (IGF-IR) in response to IGF-I was decreased in the bmMSCs of aged donors. Conversely, data showed that decorin (DCN) expression was prominently increased in aged bmMSCs, and that under IGF-I treatment, DCN knockdown in serum-starved aged bmMSCs potentiated their mitogenic activity and IGF-IR auto-phosphorylation, whereas DCN overexpression in serum-starved adult bmMSCs decreased both activities. Co-immunoprecipitation assays suggested that IGF-I and DCN bound to IGF-IR in a competitive manner. Online MethPrimer predicted 4 CpG islands (CGIs) in the introns of DCN gene. RT-qPCR and bisulfite sequencing showed that dimethyloxalylglycine, an inhibitor of DNA demethylation, increased DCN mRNA expression and CGI-I methylation in adult bmMSCs, whereas 5-aza-2’-deoxycytidine, a DNA methylation inhibitor, decreased DCN mRNA expression and CGI-I methylation in aged bmMSCs, and ultimately enhanced the proliferation of serum-starved aged bmMSCs under IGF-I stimulation. Thus, IGF-IR could be the prime target of aging in down-regulating the IGF-I signaling of bmMSCs, where DCN could be a critical mediator.

Identifying hub genes of papillary thyroid carcinoma in the TCGA and GEO database using bioinformatics analysis

Background

Thyroid carcinoma (THCA) is a common endocrine malignant tumor. Papillary carcinoma with low degree of malignancy and good prognosis is the most common. It can occur at any age, but it is more common in young adults. Although the mortality rate is decreased due to early diagnosis, the survival rate varies depending on the type of tumor. Therefore, the purpose of this study is to identify hub biomarkers and novel therapeutic targets for THCA.

Methods

The GSE3467, GSE3678, GSE33630 and GSE53157 were obtained from the GEO database, including 100 thyroid tumors and 64 normal tissues to obtain the intersection of differentially expressed genes, and a protein-protein interaction network was constructed to obtain the HUB gene. The corresponding overall survival information from The Cancer Genome Atlas Project-THCA was then included in this research. The signature mechanism was studied by analyzing the gene ontology and the Kyoto Encyclopedia of Genes and Genome database.

Results

In this research, we identified eight candidate genes (FN1, CCND1, CDH2, CXCL12, MET, IRS1, DCN and FMOD) from the network. Also, expression verification and survival analysis of these candidate genes based on the TCGA database indicate the robustness of the above results. Finally, our hospital samples validated the expression levels of these genes.

Conclusion

The research identified eight mRNA (four up–regulated and four down–regulated) which serve as signatures and could be a potential prognostic marker of THCA.

Protective Role of Decorin in Primary Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) represents one of the most frequent type of primary liver cancers. Decorin, a small leucine-rich proteoglycan of the extracellular matrix, represents a powerful tumor cell growth and migration inhibitor by hindering receptor tyrosine kinases and inducing p21^WAF1/CIP1. In this study, first we tested decorin expression in HCCs utilizing in silico data, as well as formalin fixed paraffin embedded tissue samples of HCC in a tissue microarray (TMA). In silico data revealed that DCN/SMA mRNA ratio is decreased in HCC compared to normal tissues and follows the staging of the disease. Among TMA samples, 52% of HCCs were decorin negative, 33% exhibited low, and 15% high decorin levels corroborating in silico results. In addition, applying conditioned media of hepatoma cells inhibited decorin expression in LX2 stellate cells in vitro. These results raise the possibility that decorin acts as a tumor suppressor in liver cancer and that is why its expression decreased in HCCs. To further test the protective role of decorin, the proteoglycan was overexpressed in a mouse model of hepatocarcinogenesis evoked by thioacetamide (TA). After transfection, the excessive proteoglycan amount was mainly detected in hepatocytes around the central veins. Upon TA-induced hepatocarcinogenesis, the highest tumor count was observed in mice with no decorin production. Decorin gene delivery reduced tumor formation, in parallel with decreased pEGFR, increased pIGF1R levels, and with concomitant induction of pAkt (T308) and phopho-p53, suggesting a novel mechanism of action. Our results suggest the idea that decorin can be utilized as an anti-cancer agent.

The impact of emphysema on surgical outcomes of early-stage lung cancer: a retrospective study

BACKGROUND

The presence of emphysema on computed tomography (CT) is associated with an increased frequency of lung cancer, but the postoperative outcomes of patients with pulmonary emphysema are not well known. The objective of this study was to investigate the association between the extent of emphysema and long-term outcomes, as well as mortality and postoperative complications, in early-stage lung cancer patients after pulmonary resection.

METHODS

The clinical records of 566 consecutive lung cancer patients who underwent pulmonary resection in our department were retrospectively reviewed. Among these, the data sets of 364 pathological stage I patients were available. The associations between the extent of lung emphysema and long-term outcomes and postoperative complications were investigated. Emphysema was assessed on the basis of semiquantitative CT. Surgery-related complications of Grade ≥ II according to the Clavien-Dindo classification were included in this study.

RESULTS

Emphysema was present in 63 patients. The overall survival and relapse-free survival of the non-emphysema and emphysema groups at 5 years were 89.0 and 61.3% (P < 0.001), respectively, and 81.0 and 51.7%, respectively (P < 0.001). On multivariate analysis, significant prognostic factors were emphysema, higher smoking index, and higher histologic grade (p < 0.05). Significant risk factors for poor recurrence-free survival were emphysema, higher smoking index, higher histologic grade, and presence of pleural invasion (P < 0.05). Regarding Grade ≥ II postoperative complications, pneumonia and supraventricular tachycardia were more frequent in the emphysema group than in the non-emphysema group (P = 0.003 and P = 0.021, respectively).

CONCLUSION

The presence of emphysema affects the long-term outcomes and the development of postoperative complications in early-stage lung cancer patients.

Investigating the mechanism by which SMAD3 induces PAX6 transcription to promote the development of non-small cell lung cancer

Background

This study investigated the function of SMAD3 (SMAD family member 3) in regulating PAX6 (paired box 6) in non-small cell lung cancer.

Methods

First, qRT-PCR was employed to detect SMAD3 expression in cancer tissues along with normal tissues and four cell lines, including BEAS-2B, H125, HCC827 and A549 cells. SMAD3 was knocked down by small interference RNA (siRNA), and then its expression was determined via qRT-PCR and Western blot analysis. The correlation between SMAD3 and PAX6 was determined by double luciferase reporter experiments and chromatin immunoprecipitation (ChIP) assay. Cell viability was evaluated by CCK-8 and colony forming assays, while cell migration and invasion were detected by Transwell analysis.

Results

SMAD3 and PAX6 were upregulated in lung cancer tissues and cancer cells. Knocking down SMAD3 and PAX6 by transfection with siRNAs specifically suppressed the expression of SMAD3 and PAX6 mRNA and protein levels. SMAD3 could promote PAX6 transcriptional activity by binding to its promoter. Reduced expression of SMAD3 led to the downregulation of PAX6 mRNA and protein levels along with decreased cell migration, invasion, proliferation and viability in A549 and HCC827 cells. PAX6 overexpression altered the si-SMAD3-induced inhibition of cell migration, invasion, proliferation and viability in A549 and HCC827 cells. Additionally, PAX6 knockdown alone also repressed the cell migration, invasion, proliferation and viability of the cell lines.

Conclusions

SMAD3 promotes the progression of non-small cell lung cancer by upregulating PAX6 expression.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0948-z) contains supplementary material, which is available to authorized users.

Clinicopathologic characteristics of non-small cell lung cancer in patients with smoking-related chronic obstructive pulmonary disease

BACKGROUND

The purpose of this study was to clarify the clinicopathologic characteristics of non-small cell lung cancer (NSCLC) patients with smoking-related chronic obstructive pulmonary disease (COPD) and to evaluate the biological behavior of this disease. We investigated the association between smoking-related COPD, the recurrence-free proportion (RFP) and the clinicopathological features of clinical stage I NSCLC patients.

METHODS

Between 2005 and 2014, 218 consecutive patients with clinical stage I NSCLC underwent complete resection with lobectomy or greater and systematic lymph node dissection. Differences in categorical outcomes were evaluated by the χ² test. RFPs were estimated using the Kaplan-Meier method, and differences were evaluated using the log-rank test.

RESULTS

The 5-year RFP of clinical stage I NSCLC patients with smoking-related COPD was 55%, which was significantly lower than in those without smoking-related COPD (85%; p < 0.001). Postoperative pathological factors, including moderate or poor histological differentiation, intratumoral vascular invasion and lymph node metastasis, were detected more often in patients with smoking-related COPD. In adenocarcinoma patients, the 5-year RFP of patients with smoking-related COPD was 47%, which was significantly lower than in those without smoking-related COPD (87%; p < 0.001). The presence of a solid component was more frequently found in patients with smoking-related COPD (p = 0.007).

CONCLUSION

Clinical stage I NSCLC patients with smoking-related COPD have histologically more invasive tumors than those without smoking-related COPD.

P21-activated kinase 7 (PAK7) interacts with and activates Wnt/β-catenin signaling pathway in breast cancer

Background: Breast cancer is the highest incidence of tumor in women, which seriously threaten women's health. The occurrence and progression of breast cancer is linked to inactivation or downregulation of tumor suppressors, and activation or upregulation of oncogenes. However, the mechanism of PAK7 involving in the occurrence and progression of breast cancer is not yet fully understood. Methods: PAK7 expression was analyzed by RT-qPCR and immunohistochemistry and correlated with clinicopatholgical parameters in breast cancer tissue microarray. The effects of PAK7 on breast cancer cells were detected by CCK-8 assay, colon formation assay, wound healing and transwell assays, and flow cytometry. The relationship between PAK7 and Wnt/β-catenin signaling pathway was determined by western blotting, TOP/FOP flash, co-Immunoprecipitation and co-localization assays. Results: PAK7 expression was significantly increased in breast cancer tissues and positively correlated with pathological differentiation and TNM stage of breast cancer. Overexpression of PAK7 could significantly promote proliferation and migration of breast cancer cells, and inhibit apoptosis. In contrast, PAK7 knockdown significantly inhibited the proliferation and migration of breast cancer cells and promoted apoptosis. In addition, PAK7 could activate Wnt/β-catenin signaling pathway in breast cancer cells. Further study found that PAK7 could directly bind to GSK3β and β-catenin, and regulate β-catenin degradation by phosphorylating GSK3β. Conclusions: Our study demonstrated that PAK7, as an oncogene, involved in breast cancer progression by activating the Wnt/β-catenin signaling pathway, suggesting that the potential applicability of PAK7 as a target for breast cancer treatment.

Methylated +322-327 CpG site decreases hOGG1 mRNA expression in non-small cell lung cancer

hOGG1 plays a role in several disease pathways, including various cancers. Despite such functional importance, how hOGG1 is regulated at the transcriptional level in human non-small cell lung cancer (NSCLC) remains unknown, particularly via DNA methylation changes. We obtained NSCLC tissues and adjacent non-cancerous tissues and examined hOGG1 mRNA expression levels. NSCLC cells were treated with 5-Aza to test whether DNA methylation can influence the expression of hOGG1. The MassARRAY EpiTYPER and luciferase reporter gene assays were used to define the functional region of the hOGG1 gene (including CpG sites). Finally, ChIP assay was utilized to verify transcription factor binding to the hOGG1 5'-UTR region. Our previous studies supported the idea that the methylation of the hOGG1 gene promoter region occurs frequently in NSCLC. Treatment with 5-Aza, a demethylating agent, led to a significant restoration of hOGG1 expression in NSCLC cell lines. Quantitative PCR and MassARRAY EpiTYPER assays demonstrated that methylation of the +322-327 CpG site in the 5'-UTR region of hOGG1 was higher in NSCLC tissues compared with adjacent non-cancerous tissues. Notably, the methylation level of +322-327 site (T/N) was inversely correlated with that of hOGG1 mRNA level (T/N) in 25 NSCLC tissues. ChIP assay and in silico prediction showed an association between the +322-327 CpG site and Sp1, which has been reported to be an activator of transcription. Importantly, luciferase reporter gene and ChIP assays showed that +322-327 CpG site methylation particularly reduced the recruitment of Sp1 to the 5'-UTR sequence in hOGG1 and reduced transcriptional activity ~50%. In summary, we have demonstrated that hOGG1 mRNA is downregulated in NSCLC tissues. Moreover, we identified that the methylated +322-327 CpG site in the hOGG1 5'-UTR is associated with reduced expression of hOGG1 by decreasing the recruitment of Sp1 to the 5'-UTR of hOGG1.

Targeting roles of inflammatory microenvironment in lung cancer and metastasis

Inflammatory cells and mediators are essential components in tumor microenvironment and play decisive roles in the initiation, proliferation, survival, promotion, invasion, or metastasis of lung cancer. Clinical and epidemiologic studies suggested a strong association between inflammation and lung cancer and an influence of immune surveillances and tumor responses to chemotherapeutic drugs, although roles of inflammation in lung cancer remain unclear. The present review outlined roles of inflammation in lung cancer, with particular focus on inflammatory components, types, biomarkers, or principal mechanisms by which the inflammation contributes to the development of lung cancer. The cancer-associated inflammatory cells (CICs) should be furthermore defined and include cancer-specific and interacted cells with inflammatory or inflammation-like characteristics, e.g., innate or adaptive immune cells and cancer tissue cells. We also discuss targeting potentials of inflammation in the prevention and treatment of lung cancer. The diversity of cancer-related inflammatory microenvironment is instrumental to design novel therapeutic approaches for lung cancer.

Reduced decorin expression in the tumor stroma correlates with tumor proliferation and predicts poor prognosis in patients with I-IIIA non-small cell lung cancer

Decorin, chiefly synthesized by tumor stroma, is known as a tumor suppressor. However, the clinical and prognostic significance in lung cancer remained unclear. Here, decorin and Ki67 expression was detected by immunohistochemistry (IHC) in I-IIIA non-small cell lung cancer (NSCLC) tissues (n = 264) in comparison to adjacent normal tissues (n = 40). The relationship between the expression of decorin and clinical characteristics, as well as Ki67 index and prognosis, was analyzed. Decorin expression was decreased in both the stroma (P < 0.001) and the tumor cells (P = 0.038) in NSCLC specimens. There was the lowest stromal expression of decorin in patients with G3 adenocarcinoma and higher Ki67 index in the stromal decorin-negative group. The Kaplan-Meier survival analysis demonstrated that lack of decorin in the stroma was correlated with a shorter DFS and OS (P = 0.005 and P = 0.010, respectively), while there was no significant association between decorin expression in the tumor cells and outcome. Multivariate analysis showed that reduced expression of decorin in the stroma was an independent prognostic factor for poor outcome including DFS (HR = 5.685, 95 % CI 0.493-0.933; P = 0.017) and OS (HR = 6.579, 95 % CI 0.484-0.908; P = 0.010). Negative decorin in the stroma combined with high Ki67 index predicted poorer outcomes for I-IIIA NSCLC patients. Our results provide data on decorin expression in both the stroma and cancer cells in NSCLC and reveal that reduced expression of stromal decorin correlates with high Ki67 index and has prognostic significance for poor outcome in I-IIIA NSCLC. Our data suggest that evaluating stromal decorin expression might be useful in assessing the prognosis and malignant potential.

Next-Generation Sequencing and Applications to the Diagnosis and Treatment of Lung Cancer

Cancer is a genetic disease characterized by uncontrolled growth of abnormal cells. Over time, somatic mutations accumulate in the cells of an individual due to replication errors, chromosome segregation errors, or DNA damage. When not caught by traditional mechanisms, these somatic mutations can lead to cellular proliferation, the hallmark of cancer. Lung cancer is the leading cause of cancer-related mortality in the United States, accounting for approximately 160,000 deaths annually. Five year survival rates for lung cancer remain low (<50 %) for all stages, with even worse prognosis (<15 %) in late stage cases. Technological advances, including advances in next-generation sequencing (NGS), offer the vision of personalized medicine or precision oncology, wherein an individual's treatment can be based on his or her individual molecular profile, rather than on historical population-based medicine. Towards this end, NGS has already been used to identify new biomarker candidates for the early diagnosis of lung cancer and is increasingly used to guide personalized treatment decisions. In this review we will provide a high-level overview of NGS technology and summarize its application to the diagnosis and treatment of lung cancer. We will also describe how NGS can drive advances that bring us closer to precision oncology and discuss some of the technical challenges that will need to be overcome in order to realize this ultimate goal.

Impact of chronic obstructive pulmonary disease on postoperative recurrence in patients with resected non-small-cell lung cancer

Purpose

This study aimed to determine whether the severity of chronic obstructive pulmonary disease (COPD) affects recurrence-free survival in non-small-cell lung cancer (NSCLC) patients after surgical resection.

Patients and methods

A retrospective study was performed on 421 consecutive patients who had undergone lobectomy for NSCLC from January 2008 to June 2011. Classification of COPD severity was based on guidelines of the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Characteristics among the three subgroups were compared and recurrence-free survivals were analyzed.

Results

A total of 172 patients were diagnosed with COPD (124 as GOLD-1, 46 as GOLD-2, and two as GOLD-3). The frequencies of recurrence were significantly higher in patients with higher COPD grades (P<0.001). Recurrence-free survival at 5 years was 78.1%, 70.4%, and 46.4% in non-COPD, mild COPD, and moderate/severe COPD groups, respectively (P<0.001). By univariate analysis, the age, sex, smoking history, COPD severity, tumor size, histology, and pathological stage were associated with recurrence-free survival. Multivariate analysis showed that older age, male, moderate/severe COPD, and advanced stage were independent risk factors associated with recurrence-free survival.

Conclusion

NSCLC patients with COPD are at high risk for postoperative recurrence, and moderate/severe COPD is an independent unfavorable prognostic factor.

Inactivation of BLU is associated with methylation of Sp1-binding site of BLU promoter in gastric cancer

BLU is a candidate tumor suppressor gene, which is epigenetically inactivated in many human malignancies. However, the expression and biological functions of BLU in gastric cancer has not yet been reported. In the present study, we identified a functional BLU promoter which was regulated by the transcription activator Sp1. Bisulfite sequencing and qRT-PCR assays indicated that the silence of BLU expression in gastric cancer was significantly associated with DNA hypermethylation of BLU promoter including -39 CpG site located in the Sp1 transcription element. The expression of BLU was notably restored in AGS and SGC7901 cells following the demethylation-treatment with 5'-Aza-2'-deoxycytidine. Moreover, the results from ChIP, EMSA and luciferase reporter gene showed that -39 CpG methylation could prevent Sp1 from binding to the promoter of BLU and decreased transcription activity of the BLU gene by ~70%. In addition, knockdown of BLU significantly promoted cellular proliferation and colony formation in gastric cancer cells. In conclusion, we identified a novel functional BLU promoter and proved that BLU promoter activity was regulated by Sp1. Furthermore, we found that hypermethylated -39 CpG in BLU proximal promoter directly reduced its binding with Sp1, which may be one of the mechanisms accounting for the inactivation of BLU in gastric cancer.

RNF111/Arkadia is regulated by DNA methylation and affects TGF-β/Smad signaling associated invasion in NSCLC cells

OBJECTIVES

RNF111/Arkadia is a critical regulator of TGF-β signaling, being required for SMAD3-mediated responses such as TGF-β-induced repression of E-cadherin. Previous studies show that mutations in RNF111 in human cancers are rare and RNF111 promotes lung tumor metastasis. However, the epigenetic mechanisms underlying the role of RNF111 in non-small cell lung cancer (NSCLC) metastasis remain unknown. Here, we mainly focused on low- (95C) and high-metastatic (95D) NSCLC cell lines, which share a similar genetic background, and investigated the methylation-based regulation of RNF111 expression.

MATERIALS AND METHODS

Clonal bisulfite sequencing, real-time qRT-PCR, western blot analysis, luciferase reporter assays, RNA interference, chromatin immunoprecipitation (ChIP) assay and transwell migration and invasion assays were performed on human NSCLC cell lines 95C and 95D.

RESULTS

RNF111 was high-expressed in 95D cells, which showed low-level methylation at -459CpG site in RNF111 promoter. The opposite results were obtained in 95C cells. Cell-based and biochemical assays revealed that -459CpG methylation can inhibit RNF111 transcriptional expression by interfering with the recruitment of Sp1 to RNF111 promoter. On TGF-β stimulation, siRNA-mediated RNF111 knockdown inhibited TGF-β/Smad signaling activity and Snail (an inducer of metastasis) expression, and enhanced E-cadherin (an epithelial-to-mesenchymal transition marker) expression in 95C and 95D cells. Furthermore, demethylation-induced upregulation of RNF111 enhanced phosphorylation of SMAD3 and Snail expression, and repressed E-cadherin expression in 95C cells expressing low RNF111.

CONCLUSIONS

Our results suggest that -459CpG methylation in Sp1-binding site of RNF111 promoter transcriptionally decreases RNF111 expression, which inhibits TGF-β/Smad signaling associated invasion in NSCLC cells.

Repression of TIF1γ by SOX2 promotes TGF-β-induced epithelial-mesenchymal transition in non-small-cell lung cancer

TIF1γ is a novel regulator of transforming growth factor (TGF)-β/Smad signaling. Our previous studies show that dysregulated expression of transcriptional intermediary factor 1 γ (TIF1γ) and abnormal TGF-β/Smad signaling are implicated in non-small-cell lung cancer (NSCLC) separately. However, how TIF1γ contributes to NSCLC by controlling TGF-β/Smad signaling is poorly understood. Here, we investigated the mechanistic role of TIF1γ in TGF-β-induced epithelial-mesenchymal transition (EMT), as well as a link between TIF1γ and SOX2 in NSCLC. We show that TIF1γ is a downstream target of SOX2 in NSCLC cells. SOX2 overexpression negatively regulated TIF1γ promoter activity and thereby attenuated TIF1γ mRNA and protein expression levels; SOX2 knockdown significantly enhanced TIF1γ promoter activity and augmented TIF1γ expression. Moreover, TIF1γ mRNA expression was downregulated in human NSCLC tissues and negatively correlated with SOX2 protein, which was upregulated in NSCLC tissues. Importantly, knockdown of TIF1γ or SOX2 overexpression augmented SMAD4 (human Mad (mothers against decapentaplegic)-related homologous protein 4)-dependent transcriptional responses, and enhanced TGF-β-induced EMT and human NSCLC cell invasion; knockdown of SOX2 impaired TGF-β-induced EMT and NSCLC cell invasion. In an in vivo model of metastasis, knockdown of TIF1γ promotes NSCLC cell metastasis. In addition, our data suggested that TIF1γ inhibited TGF-β-induced EMT through competing with SMAD4 in NSCLC cells. Taken together, our findings reveal a new mechanism by which SOX2-mediated transcription repression of TIF1γ promotes TGF-β-induced EMT in NSCLC.

Epigenetic mechanisms in cancer: push and pull between kneaded erasers and fate writers

Research concerning the epigenome over the years has systematically and sequentially shown substantial development and we have moved from global inhibition of modifications of the epigenome toward identification and targeted therapy against tumor-specific epigenetic mechanisms. In accordance with this approach, several drugs with epigenetically modulating activity have received considerable attention and appreciation, and recently emerging scientific evidence is uncovering details of their mode of action. High-throughput technologies have considerably improved our existing understanding of tumor suppressors, oncogenes, and signaling pathways that are key drivers of cancer. In this review, we summarize the general epigenetic mechanisms in cancer, including: the post-translational modification of DNA methyltransferase and its mediated inactivation of Ras association domain family 1 isoform A, Sonic hedgehog signaling, Wnt signaling, Notch signaling, transforming growth factor signaling, and natural products with epigenetic modification ability. Moreover, we introduce the importance of nanomedicine for delivery of natural products with modulating ability to epigenetic machinery in cancer cells. Such in-depth and comprehensive knowledge regarding epigenetic dysregulation will be helpful in the upcoming era of molecular genomic pathology for both detection and treatment of cancer. Epigenetic information will also be helpful when nanotherapy is used for epigenetic modification.