Esophageal cancer is a deadly disease, ranking sixth among all cancers in mortality. Despite incremental advances in diagnostics and therapeutics, esophageal cancer still carries a poor prognosis, and thus, there remains a need to elucidate the molecular mechanisms underlying this disease. There is accumulating evidence that a comprehensive understanding of the molecular composition of esophageal cancer requires attention to not only tumor cells but also the tumor microenvironment (TME), which contains diverse cell populations, signaling factors and structural molecules that interact with tumor cells and support all stages of tumorigenesis. In esophageal cancer, environmental exposures can trigger chronic inflammation, which leads to constitutive activation of pro-inflammatory signaling pathways that promote survival and proliferation. Antitumor immunity is attenuated by cell populations such as myeloid-derived suppressor cells and regulatory T cells, as well as immune checkpoints like programmed death-1. Other immune cells such as tumor-associated macrophages can have other pro-tumorigenic functions, including the induction of angiogenesis and tumor cell invasion. Cancer-associated fibroblasts secrete growth factors and alter the extracellular matrix to create a tumor niche and enhance tumor cell migration and metastasis. Further study of how these TME components relate to the different stages of tumor progression in each esophageal cancer subtype will lead to development of novel and specific TME-targeting therapeutic strategies, which offer considerable potential especially in the setting of combination therapy.

The tumor microenvironment in esophageal cancer

Phenotypic and functional heterogeneity is one of the hallmarks of human cancers. Tumor genotype variations among tumors within different patients are known as interpatient heterogeneity, and variability among multiple tumors of the same type arising in the same patient is referred to as intra-patient heterogeneity. Subpopulations of cancer cells with distinct phenotypic and molecular features within a tumor are called intratumor heterogeneity (ITH). Since Nowell proposed the clonal evolution of tumor cell populations in 1976, tumor heterogeneity, especially ITH, was actively studied. Research has focused on the genetic basis of cancer, particularly mutational activation of oncogenes or inactivation of tumor-suppressor genes (TSGs). The phenomenon of ITH is commonly explained by Darwinian-like clonal evolution of a single tumor. Despite the monoclonal origin of most cancers, new clones arise during tumor progression due to the continuous acquisition of mutations. It is clear that disruption of the "epigenetic machinery" plays an important role in cancer development. Aberrant epigenetic changes occur more frequently than gene mutations in human cancers. The epigenome is at the intersection of the environment and genome. Epigenetic dysregulation occurs in the earliest stage of cancer. The current trend of epigenetic therapy is to use epigenetic drugs to reverse and/or delay future resistance to cancer therapies. A majority of cancer therapies fail to achieve durable responses, which is often attributed to ITH. Epigenetic therapy may reverse drug resistance in heterogeneous cancer. Complete understanding of genetic and epigenetic heterogeneity may assist in designing combinations of targeted therapies based on molecular information extracted from individual tumors.

/pdf/epigenetic-heterogeneity-in-cancer-4o1txdvf1z.pdf

Epigenetic heterogeneity in cancer

S This research aimed to explore effects of SIX1 and DACH1 on hepatocellular carcinoma (HCC) cell proliferation, apoptosis and cell cycle. Fifty paired hepatocellular carcinoma tissues were screened for differentially expressed genes. SIX1 and DACH1 expressions were subjected to qRT-PCR and western blot in tumor tissues and cells. The knockdown efficiency of siRNAs and transfection efficiency of cDNAs and siRNAs were validated by qRT-PCR and western blot as well. Then colony formation assay and flow cytometry were applied to observe cell proliferation, cell apoptosis and cell cycle changes. Immunofluorescence co-localization and immunoprecipitation were used to analyze the interaction between proteins which was quantified using western blot. Effects of SIX1 and DACH1 on tumor growth and their expressions in tumors were confirmed in vitro in nude mice model. Results of these experiments showed that SIX1 was overexpressed while DACH1 was suppressed in HCC tissues and cells. The suppression of SIX1 and overexpression of DACH1 not only inhibited cell proliferation, but also induced cell apoptosis and arrested cell cycle in G2/M phase compared with control group. Results of immunofluorescence co-localization suggested that SIX1, p53 and DACH1 were significantly overlapped. Immunoprecipitation showed that DACH1 (marked with Flag tag) could pull down p53 and SIX1, but SIX1 (marked with His tag) could only pull down DACH1, which indicated that an indirect regulation between SIX1 and p53. Validated with western blot afterwards, DACH1 overexpression suppressed tumorigenesis in vivo by up-regulating p53 expression while SIX1 overexpression accelerated tumor growth by down-regulating p53 expression. Therefore, the decrease of SIX1 facilitated the expression of DACH1, thus activated the expression of p53 and suppressed the progression of HCC both in vitro and in vivo.

SIX1 and DACH1 influence the proliferation and apoptosis of hepatocellular carcinoma through regulating p53

The potential of expression profiling using microarray analysis as a tool to predict the prognosis for different types of cancer has been realized. This study aimed to identify a novel biomarker for colorectal cancer (CRC). The expression profiles of cancer cells in 152 patients with stage I-III CRC were examined using microarray analysis. High expression in CRC cells, especially in patients with distant recurrences, was a prerequisite to select candidate genes. Thus, we identified seventeen candidate genes, and selected Traf2- and Nck-interacting kinase (TNIK), which was known to be associated with progression in CRC through Wnt signaling pathways. We analyzed the protein expression of TNIK using immunohistochemistry (IHC) and investigated the relationship between protein expression and patient characteristics in 220 stage I-III CRC patients. Relapse-free survival was significantly worse in the TNIK high expression group than in the TNIK low expression group in stage II (p = 0.028) and stage III (p = 0.006) patients. In multivariate analysis, high TNIK expression was identified as a significant independent risk factor of distant recurrence in stage III patients. This study is the first to demonstrate the prognostic significance of intratumoral TNIK protein expression in clinical tissue samples of CRC, in that high expression of TNIK protein in primary tumors was associated with distant recurrence in stage II and III CRC patients. This TNIK IHC study might contribute to practical decision-making in the treatment of these patients.

/pdf/prognostic-significance-of-traf2-and-nck-interacting-kinase-x9y32i1cn9.pdf

Prognostic significance of Traf2- and Nck- interacting kinase (TNIK) in colorectal cancer

Hepatocellular carcinoma (HCC) is difficult to diagnose early, resulting in only 30% resection rate. HCC is a relatively chemo-resistant tumor, molecular targeted therapy can only benefit approximately 30% patients with liver cancer. Bufalin (Bu) is one of the topoisomerase II inhibitors, many studies have recently focused on the anticancer activities of bufalin. In the present study, we report that bufalin can inhibit the proliferation, invasion and metastasis of liver cancer cells via the Hh signaling pathway. The human high metastasis potential LM3 hepatoma cells (HCC-LM3) were cultured in vitro, bufalin and/or Hedgehog signaling pathway inhibitors (GANT61, cyclopamine) was added into cell culture fluid for 72 h to observe the antitumor effect of bufalin. The results showed that bufalin was able to inhibit epithelial mesenchymal transition (EMT), and extracellular matrix (ECM) degradation and angiogenesis of liver cancer cells by influencing the expression of Ptch1'Gli1'Gli3 proteins in Hh signaling pathway. Bufalin could downregulate the downstream target molecules of MMP-2, MMP-9, β-catenin and VEGF in liver cancer cells by influencing the Gli1 and Gli3 expression of Hh signaling pathway, and upregulate the E-cadherin expression of liver cancer cells by influencing the Gli3 expression of Hh signaling pathway. Therefore, the present study shows that bufalin combined with Hedgehog signaling pathway inhibitors can significantly reduce the malignant biological behavior of the liver cancer cells.

/pdf/inhibitory-effect-of-bufalin-combined-with-hedgehog-4izcci5zyb.pdf

Inhibitory effect of bufalin combined with Hedgehog signaling pathway inhibitors on proliferation and invasion and metastasis of liver cancer cells

Human Dachshund homologue 1 (DACH1) is a major component of the Retinal Determination Gene Network. Loss of DACH1 expression was found in breast, prostate, lung, endometrial, colorectal and hepatocellular carcinoma. To explore the expression, regulation and function of DACH1 in human esophageal cancer, 11 esophageal cancer cell lines, 10 cases of normal esophageal mucosa, 51 cases of different grades of dysplasia and 104 cases of primary esophageal squamous cancer were employed. Methylation specific PCR, immunohistochemistry, western blot, flow cytometry, small interfering RNAs, colony formation techniques and xenograft mice model were used. We found that DACH1 expression was regulated by promoter region hypermethylation in esophageal cancer cell lines. 18.8% (6 of 32) of grade 1, 42.1% (8 of 19) of grade 2 and grade 3 dysplasia (ED2,3), and 61.5% (64 of 104) of esophageal cancer were methylated, but no methylation was found in 10 cases of normal esophageal mucosa. The methylation was increased in progression tendency during esophageal carcinogenesis (P<0.01). DACH1 methylation was associated with poor differentiation (P<0.05) and late tumor stage (P<0.05). Restoration of DACH1 expression inhibited cell growth and activated TGF-β signaling in KYSE150 and KYSE510 cells. DACH1 suppressed human esophageal cancer cell tumor growth in xenograft mice. In conclusion, DACH1 is frequently methylated in human esophageal cancer and methylation of DACH1 is involved in the early stage of esophageal carcinogenesis. DACH1 expression is regulated by promoter region hypermethylation. DACH1 suppresses esophageal cancer growth by activating TGF-β signaling.

/pdf/silencing-dach1-promotes-esophageal-cancer-growth-by-1xuofesbj8.pdf

Silencing DACH1 promotes esophageal cancer growth by inhibiting TGF-β signaling.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Yan Nie

Author Tools

Chat about Author

Papers

Silencing DACH1 promotes esophageal cancer growth by inhibiting TGF-β signaling.