IRX1 influences peritoneal spreading and metastasis via inhibiting BDKRB2-dependent neovascularization on gastric cancer. Oncogene. 2011;30:4498-4508. [PMID: 21602894 PMCID: PMC3208739 DOI: 10.1038/onc.2011.154]

LncRNA UCA1 promotes vasculogenic mimicry by targeting miR-1-3p in gastric cancer

Long noncoding RNA urothelial carcinoma-associated 1 (UCA1) has been implicated in several tumors. UCA1 promotes cell proliferation, migration, and invasion of gastric cancer (GC) cells, but the molecular mechanism has not been fully elucidated. This study revealed the oncogenic effects of UCA1 on cell growth and invasion. Furthermore, UCA1 expression was significantly correlated with the overall survival of GC patients, and the clinicopathological indicators, including tumor size, depth of invasion, lymph node metastasis, and TNM stage. Additionally, miR-1-3p was identified as a downstream target of UCA1, which was negatively regulated by UCA1. MiR-1-3p inhibited cell proliferation and vasculogenic mimicry (VM), and induced cell apoptosis by upregulating BAX, BAD, and tumor suppressor TP53 expression levels. Moreover, miR-1-3p almost completely reversed the oncogenic effect caused by UCA1, including cell growth, migration, and VM formation. This study also confirmed that UCA1 promoted tumor growth in vivo. In this study, we also revealed the correlation between UCA1 and VM formation, which is potentially crucial for tumor metastasis. Meanwhile, its downstream target miR-1-3p inhibited VM formation in GC cells. In summary, these findings indicate that the UCA1/miR-1-3p axis is a potential target for GC treatment.

Establishment of skin cutaneous melanoma prognosis model based on vascular mimicry risk score

Studies have indicated that Vascular mimicry (VM) could contribute to the unfavorable prognosis of skin cutaneous melanoma (SKCM). Thus, the objective of this study was to identify therapeutic targets associated with VM in SKCM and develop a novel prognostic model. Gene expression data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) were utilized to identify differentially expressed genes (DEGs). By intersecting these DEGs with VM genes, we acquired VM-related DEGs specific to SKCM, and then identified prognostic-related VM genes. A VM risk score system was established based on these prognosis-associated VM genes, and patients were then categorized into high- and low-score groups using the median score. Subsequently, differences in clinical characteristics, gene set enrichment analysis (GSEA), and other analyses were further presented between the 2 groups of patients. Finally, a novel prognostic model for SKCM was established using the VM score and clinical characteristics. 26 VM-related DEGs were identified in SKCM, among the identified DEGs associated with VM in SKCM, 5 genes were found to be prognostic-related. The VM risk score system, comprised of these genes, is an independent prognostic risk factor. There were significant differences between the 2 patient groups in terms of age, pathological stage, and T stage. VM risk scores are associated with epithelial biological processes, angiogenesis, regulation of the SKCM immune microenvironment, and sensitivity to targeted drugs. The novel prognostic model demonstrates excellent predictive ability. Our study identified VM-related prognostic markers and therapeutic targets for SKCM, providing novel insights for clinical diagnosis and treatment.

Multi-omics integration analysis of GPCRs in pan-cancer to uncover inter-omics relationships and potential driver genes

G protein-coupled receptors (GPCRs) are the largest drug target family. Unfortunately, applications of GPCRs in cancer therapy are scarce due to very limited knowledge regarding their correlations with cancers. Multi-omics data enables systematic investigations of GPCRs, yet their effective integration remains a challenge due to the complexity of the data. Here, we adopt two types of integration strategies, multi-staged and meta-dimensional approaches, to fully characterize somatic mutations, somatic copy number alterations (SCNAs), DNA methylations, and mRNA expressions of GPCRs in 33 cancers. Results from the multi-staged integration reveal that GPCR mutations cannot well predict expression dysregulation. The correlations between expressions and SCNAs are primarily positive, while correlations of the methylations with expressions and SCNAs are bimodal with negative correlations predominating. Based on these correlations, 32 and 144 potential cancer-related GPCRs driven by aberrant SCNA and methylation are identified, respectively. In addition, the meta-dimensional integration analysis is carried out by using deep learning models, which predict more than one hundred GPCRs as potential oncogenes. When comparing results between the two integration strategies, 165 cancer-related GPCRs are common in both, suggesting that they should be prioritized in future studies. However, 172 GPCRs emerge in only one, indicating that the two integration strategies should be considered concurrently to complement the information missed by the other such that obtain a more comprehensive understanding. Finally, correlation analysis further reveals that GPCRs, in particular for the class A and adhesion receptors, are generally immune-related. In a whole, the work is for the first time to reveal the associations between different omics layers and highlight the necessity of combing the two strategies in identifying cancer-related GPCRs.

IRX1 is a novel gene, overexpressed in high-grade IDH-mutant astrocytomas

BACKGROUND

IDH-mutant astrocytomas include CNS WHO grade 2 (A2), grade 3 (A3) and grade 4 (A4), of which A3 and A4 are high-grade. A3 has a heterogenous clinical outcome that cannot be explained entirely by the existing molecular biomarkers. We comprehensively studied the transcriptome profile of A3 to determine clinical significance.

METHODS

TCGA mRNA-sequencing data of A3 was analyzed to derive differentially expressed genes (DEG), which were short-listed using various approaches. mRNA expression of the short-listed genes was validated using NanoString platform on a uniformly treated and molecularly characterized A3 cohort. Protein expression of one prognostically significant gene, Iroquois-class homeodomain (IRX1) was assessed by immunohistochemistry and correlated with patient survival and tumor recurrence. IRX1 expression was also studied in different grades of astrocytoma. Since DNA methyltransferase 3 alpha (DNMT3A) influences IRX1 expression, its mutations were evaluated in a subset of tumors.

RESULTS

TCGA analysis identified 96 DEG in A3 tumours. 57 genes were short-listed and finally narrowed down to 14 genes. mRNA values of 12/14 genes validated in our cohort. On multiple-variable analysis, IRX1 was the most prognostically relevant gene, with respect to progression free survival of patients. Further, IRX1 immunoexpression was significantly higher in A3 and A4 when compared to A2 and glioblastoma. Higher IRX1 immunoexpression correlated with poor prognosis in patients with A3 tumours. Also, a higher IRX1 expression was associated with DNMT3A mutation.

CONCLUSION

Our study identifies IRX1 as a novel biomarker overexpressed in high-grade IDH-mutant astrocytomas with prognostic significance in A3. DNMT3A mutation probably modulates IRX1 expression.

Iroquois Family Genes in Gastric Carcinogenesis: A Comprehensive Review

Gastric cancer (GC) is the fifth leading cause of cancer-associated death worldwide, accounting for 768,793 related deaths and 1,089,103 new cases in 2020. Despite diagnostic advances, GC is often detected in late stages. Through a systematic literature search, this study focuses on the associations between the Iroquois gene family and GC. Accumulating evidence indicates that Iroquois genes are involved in the regulation of various physiological and pathological processes, including cancer. To date, information about Iroquois genes in GC is very limited. In recent years, the expression and function of Iroquois genes examined in different models have suggested that they play important roles in cell and cancer biology, since they were identified to be related to important signaling pathways, such as wingless, hedgehog, mitogen-activated proteins, fibroblast growth factor, TGFβ, and the PI3K/Akt and NF-kB pathways. In cancer, depending on the tumor, Iroquois genes can act as oncogenes or tumor suppressor genes. However, in GC, they seem to mostly act as tumor suppressor genes and can be regulated by several mechanisms, including methylation, microRNAs and important GC-related pathogens. In this review, we provide an up-to-date review of the current knowledge regarding Iroquois family genes in GC.

Variation of DNA methylation on the IRX1/2 genes is responsible for the neural differentiation propensity in human induced pluripotent stem cells

Introduction

Human induced pluripotent stem cells (hiPSCs) are useful tools for reproducing neural development in vitro. However, each hiPSC line has a different ability to differentiate into specific lineages, known as differentiation propensity, resulting in reduced reproducibility and increased time and funding requirements for research. To overcome this issue, we searched for predictive signatures of neural differentiation propensity of hiPSCs focusing on DNA methylation, which is the main modulator of cellular properties.

Methods

We obtained 32 hiPSC lines and their comprehensive DNA methylation data using the Infinium MethylationEPIC BeadChip. To assess the neural differentiation efficiency of these hiPSCs, we measured the percentage of neural stem cells on day 7 of induction. Using the DNA methylation data of undifferentiated hiPSCs and their measured differentiation efficiency into neural stem cells as the set of data, and HSIC Lasso, a machine learning-based nonlinear feature selection method, we attempted to identify neural differentiation-associated differentially methylated sites.

Results

Epigenome-wide unsupervised clustering cannot distinguish hiPSCs with varying differentiation efficiencies. In contrast, HSIC Lasso identified 62 CpG sites that could explain the neural differentiation efficiency of hiPSCs. Features selected by HSIC Lasso were particularly enriched within 3 Mbp of chromosome 5, harboring IRX1, IRX2, and C5orf38 genes. Within this region, DNA methylation rates were correlated with neural differentiation efficiency and were negatively correlated with gene expression of the IRX1/2 genes, particularly in female hiPSCs. In addition, forced expression of the IRX1/2 impaired the neural differentiation ability of hiPSCs in both sexes.

Conclusion

We for the first time showed that the DNA methylation state of the IRX1/2 genes of hiPSCs is a predictive biomarker of their potential for neural differentiation. The predictive markers for neural differentiation efficiency identified in this study may be useful for the selection of suitable undifferentiated hiPSCs prior to differentiation induction.

Analysis of different adipose depot gene expression in cachectic patients with gastric cancer

Purpose

This study aimed to identify the differentially expressed genes (DEGs) that contributed to the different amount of fat loss between subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) among cachectic patients.

Methods

RNA sequencing was performed and bioinformatic tools were utilized to analyze the biological functions and construct regulation networks of DEGs. We presumed that iroquois homeobox 1 (IRX1) to be a hub gene and analyzed its clinical significance. Mouse model of cancer cachexia was established and differences between SAT and VAT were compared. The function of IRX1 on lipid metabolism was clarified by Oil Red O staining, qRT-PCR, and Western blotting in adipocytes.

Results

A total of 455 DEGs were screened between SAT and VAT in cachectic patients. Several hub genes were selected and IRX1 was presumed to contribute to the pathological difference between SAT and VAT in cancer cachexia. Patients with higher expression of IRX1 in SAT than VAT revealed significantly higher weight loss, IL-6 and TNF-α, as well as lower BMI, SAT, and VAT area. IRX1 expression in SAT was negatively correlated with SAT area. In cachectic mice, the expression of IRX1 in SAT was significantly higher than that in VAT. The inhibition effect on adipogenesis exerted by IRX1 was also proved in vitro.

Conclusion

These data supported that DEGs contribute to the different degrees of fat loss among adipose depots in cachectic patients. IRX1 in SAT promoted fat loss by inhibiting adipocyte differentiation and adipogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00708-x.

An overview of kinin mediated events in cancer progression and therapeutic applications

Kinins are bioactive peptides generated in the inflammatory milieu of the tissue microenvironment, which is involved in cancer progression and inflammatory response. Kinins signals through activation of two G-protein coupled receptors; inducible Bradykinin Receptor B1 (B1R) and constitutive receptor B2 (B2R). Activation of kinin receptors and its cross-talk with receptor tyrosine kinases activates multiple signaling pathways, including ERK/MAPK, PI3K, PKC, and p38 pathways regulating cancer hallmarks. Perturbations of the kinin-mediated events are implicated in various aspects of cancer invasion, matrix remodeling, and metastasis. In the tumor microenvironment, kinins initiate fibroblast activation, mesenchymal stem cell interactions, and recruitment of immune cells. Albeit the precise nature of kinin function in the metastasis and tumor microenvironment are not completely clear yet, several kinin receptor antagonists show anti-metastatic potential. Here, we showcase an overview of the complex biology of kinins and their role in cancer pathogenesis and therapeutic aspects.

Development and Validation of a Six-Gene Prognostic Signature for Bladder Cancer

Human bladder cancer (BCa) is the most common urogenital system malignancy. Patients with BCa have limited treatment efficacy in clinical practice. Novel biomarkers could provide more crucial information conferring to cancer diagnosis, treatment, and prognosis. Here, we aimed to explore and identify novel biomarkers associated with cancer-specific survival of patients with BCa to build a prognostic signature. Based on univariate Cox regression, Lasso regression, and multivariate Cox regression analysis, we conducted an integrated analysis in the training set (GSE32894) and established a six-gene signature to predict the cancer-specific survival for human BCa. The six genes were Cyclin Dependent Kinase 4 (CDK4), E2F Transcription Factor 7 (E2F7), Collagen Type XI Alpha 1 Chain (COL11A1), Bradykinin Receptor B2 (BDKRB2), Yip1 Interacting Factor Homolog B (YIF1B), and Zinc Finger Protein 415 (ZNF415). Then, we validated the prognostic value of the model by using two other datasets (GSE13507 and TCGA). Also, we conducted univariate and multivariate Cox regression analyses, and results indicated that the six-gene signature was an independent prognostic factor of cancer-specific survival of patients with BCa. Functional analysis was performed based on the differentially expressed genes of low- and high-risk patients, and we found that they were enriched in lipid metabolic and cell division-related biological processes. Meanwhile, the gene set enrichment analysis (GSEA) revealed that high-risk samples were enriched in cell cycle and cancer-related pathways [G2/M checkpoint, E2F targets, mitotic spindle, mTOR signaling, spermatogenesis, epithelial–mesenchymal transition (EMT), DNA repair, PI3K/AKT/mTOR signaling, unfolded protein response (UPR), and MYC targets V2]. Lastly, we detected the relative expression of each signature in BCa cell lines by quantitative real-time PCR (qRT-PCR). As far as we know, currently, the present study is the first research that developed and validated a cancer-specific survival prognostic index based on three independent cohorts. The results revealed that this six-gene signature has a predictive ability for cancer-specific prognosis. Moreover, we also verified the relative expression of these six signatures between the bladder cell line and four BCa cell lines by qRT-PCR. Nevertheless, experiments to further explore the function of six genes are lacking.

Long noncoding RNA SH3PXD2A-AS1 promotes colorectal cancer progression by regulating p53-mediated gene transcription

Long non-coding RNAs (lncRNAs) play key roles in various human cancers. We aimed to determine the key lncRNAs mediating colorectal cancer (CRC) progression. We identified some lncRNAs aberrantly expressed in CRC tissues by using lncRNA microarrays and demonstrated that SH3PXD2A-AS1 was one of the most highly overexpressed lncRNAs in CRC. We further aimed to explore the roles and possible molecular mechanisms of SH3PXD2A-AS1 in CRC. RNA ISH revealed that SH3PXD2A-AS1 was overexpressed in CRC compared with adjacent normal colon tissues and indicated poor prognosis in CRC. Functional analyses showed that SH3PXD2A-AS1 enhanced cell proliferation, angiogenesis, and metastasis. Mechanistically, SH3PXD2A-AS1 can directly interact with p53 protein and regulate p53-mediated gene transcription in CRC. We provided mechanistic insights into the regulation of SH3PXD2A-AS1 on p53-mediated gene transcription and suggested its potential as a new prognostic biomarker and target for the clinical management of CRC.

The Bdkrb2 gene family provides a novel view of viviparity adaptation in Sebastes schlegelii

BACKGROUND

Black rockfish (Sebastes schlegelii) is a viviparous teleost. We proposed that the rockfish ovarian wall had a similar function to the uterus of mammals previously. In the present study, the well-developed vascular system was observed in the ovarian wall and the exterior surface of the egg membrane. In gestation, adaptation of the ovary vasculature to the rising needs of the embryos occurs through both vasodilation and neovascularization. Bdkrb2, encoding a receptor for bradykinin, plays a critical role in the control of vasodilatation by regulating nitric oxide production.

RESULTS

Eight Bdkrb2 genes were identified in the black rockfish genome. These genes were located on chromosome 14, which are arranged in a tandem array, forming a gene cluster spanning 50 kb. Protein structure prediction, phylogenetic analysis, and transcriptome analysis showed that eight Bdkrb2 genes evolved two kinds of protein structure and three types of tissue expression pattern. Overexpression of two Bdkrb2 genes in zebrafish indicated a role of them in blood vessel formation or remodeling, which is an important procedure for the viviparous rockfish getting prepared for fertilization and embryos implantation.

CONCLUSIONS

Our study characterizes eight Bdrkb2 genes in the black rockfish, which may contribute to preparation for fertilization and embryo implantation. This research provides a novel view of viviparity adaptation and lays the groundwork for future research into vascular regulation of ovarian tissue in the breeding cycle in black rockfish.

BDKRB2 is a novel EMT-related biomarker and predicts poor survival in glioma

Bradykinin receptor B2 (BDKRB2) has been reported as an oncogene in several malignancies. In glioma, the role of BDKRB2 remains unknown. This study aimed at investigating its clinical significance and biological function in glioma at the transcriptional level. We selected 301 glioma patients with microarray data from CGGA database and 697 with RNAseq data from TCGA database. Transcriptome and clinical data of 998 samples were analyzed. Statistical analysis and figure generating were performed with R language. BDKRB2 expression showed a positive correlation with the WHO grade of glioma. BDKRB2 was increased in IDH wildtype and mesenchymal subtype of glioma. Gene ontology analysis demonstrated that BDKRB2 was profoundly associated with extracellular matrix organization in glioma. GSEA analysis revealed that BDKRB2 was particularly correlated with epithelial-to-mesenchymal transition (EMT). GSVA analysis showed that BDKRB2 was significantly paralleled with several EMT signaling pathways, including PI3K/AKT, hypoxia, and TGF-β. Moreover, BDKRB2 expression was significantly correlated with key biomarkers of EMT, especially with N-cadherin, snail, slug, vimentin, TWIST1, and TWIST2. Finally, higher BDKRB2 indicated significantly shorter survival for glioma patients. In conclusion, BDKRB2 was associated with more aggressive phenotypes of gliomas. Furthermore, BDKRB2 was involved in the EMT process and could serve as an independent prognosticator in glioma.

Hormonal modulation of ESR1 mutant metastasis

Estrogen receptor alpha gene (ESR1) mutations occur frequently in ER-positive metastatic breast cancer, and confer clinical resistance to aromatase inhibitors. Expression of the ESR1 Y537S mutation induced an epithelial-mesenchymal transition (EMT) with cells exhibiting enhanced migration and invasion potential in vitro. When small subpopulations of Y537S ESR1 mutant cells were injected along with WT parental cells, tumor growth was enhanced with mutant cells becoming the predominant population in distant metastases. Y537S mutant primary xenograft tumors were resistant to the antiestrogen tamoxifen (Tam) as well as to estradiol (E2) withdrawal. Y537S ESR1 mutant primary tumors metastasized efficiently in the absence of E2; however, Tam treatment significantly inhibited metastasis to distant sites. We identified a nine-gene expression signature, which predicted clinical outcomes of ER-positive breast cancer patients, as well as breast cancer metastasis to the lung. Androgen receptor (AR) protein levels were increased in mutant models, and the AR agonist dihydrotestosterone significantly inhibited estrogen-regulated gene expression, EMT, and distant metastasis in vivo, suggesting that AR may play a role in distant metastatic progression of ESR1 mutant tumors.

IRX5 prompts genomic instability in colorectal cancer cells

The Iroquois homeobox gene 5 (IRX5), one of the members of the Iroquois homeobox family, has been identified to correlate with worse prognosis in many cancers, including colorectal cancer (CRC). In this study, upregulation of IRX5 revealed a great reduction in the proliferation of CRC colorectal cancer cell line SW480 and DLD-1, which was accompanied by G1/S arrest, increased expression in cyclin E1, P21, and P53 and a decrease in cyclin A2, B1, and D1. Furthermore, IRX5-mediated an increase expression of RH2A protein, the biomarker of DNA damage. Consequently, the SA-β-gal level is higher in IRX5-overexpression cells compared to control ones, which showed elevated DNA damage triggered cellular senescence. Recapitulating the above findings, IRX5 exhibited higher levels of genomic instability. IRX5 may be a perspective target for cancer therapy and it deserves further investigation.

Comprehensive analysis of prognosis-related methylated sites in breast carcinoma

Background

Breast carcinoma has become a nonnegligible public health problem in China with its increasing incidence and mortality in woman. As a early event regulating tumorigenesis and development, DNA methylation became one of the focuses of current carcinoma researches on potential diagnostic and therapeutic targets.

Methods

In this study, we comprehensively analyzed the gene expression data and DNA methylation data of breast carcinoma and adjacent normal tissues samples in the Gene Expression Omnibus database. Influences of tumor stage, adjuvant therapy, hormone therapy, and chemotherapy on CpG methylation level were explored by linear regression analysis. Correlations between methylation and gene expression levels were determined by spearman rank correlation analysis. Log‐rank test was applied for determining significance of associations between CpG sites methylation level and breast cancer patients' Kaplan–Meier survival.

Results

A total of 229 CpG sites were found to be significantly associated with tumor stage or treatment, and eight of which were potential markers that affect the survival of breast carcinoma and negatively correlated with their genes' expression levels.

Conclusions

We reported eight CpG sites as potential breast cancer prognosis signatures through comprehensively analyzed gene expression and DNA methylation datasets, and excluding influences of tumor stage and treatment. This should be helpful for breast cancer early diagnosis and treatment.

Targeting vasculogenic mimicry by phytochemicals: A potential opportunity for cancer therapy

Vasculogenic mimicry (VM) is regarded as a process where very aggressive cancer cells generate vascular-like patterns without the presence of endothelial cells. It is considered as the main mark of malignant cancer and has pivotal role in cancer metastasis and progression in various types of cancers. On the other hand, resistance to the antiangiogenesis therapies leads to the cancer recurrence. Therefore, development of novel chemotherapies and their combinations is urgently needed for abolition of VM structures and also for better tumor therapy. Hence, identifying compounds that target VM structures might be superior therapeutic factors for cancers treatment and controlling the recurrence and metastasis. In recent times, naturally occurring compounds, especially phytochemicals have obtained great attention due to their safe properties. Phytochemicals are also capable of targeting VM structure and also their main signaling pathways. Consequently, in this review article, we illustrated key signaling pathways in VM, and the phytochemicals that affect these structures including curcumin, genistein, lycorine, luteolin, columbamine, triptolide, Paris polyphylla, dehydroeffusol, jatrorrhizine hydrochloride, grape seed proanthocyanidins, resveratrol, isoxanthohumol, dehydrocurvularine, galiellalactone, oxacyclododecindione, brucine, honokiol, ginsenoside Rg3, and norcantharidin. The recognition of these phytochemicals and their safety profile may lead to new therapeutic agents' development for VM elimination in different types of tumors.

Downregulated microRNA-150 upregulates IRX1 to depress proliferation, migration, and invasion, but boost apoptosis of gastric cancer cells

OBJECTIVE

Many studies have reported the correlation of microRNAs (miRNAs) with cancers, yet few have proposed the function of miR-150 in gastric cancer. This study intends to discuss the role of miR-150 in gastric cancer development by regulating IRX1.

METHODS

Gastric cancer tissues and adjacent tissues were collected. MiR-150-3p, IRX1, CXCL14, and NF-κB (p65) expressions were detected. Gastric cancer cell lines SNU-1 and MKN-45 were used for subsequent cellular experiments. Cell proliferation, colony formation, migration and invasion, apoptosis, and cell cycle distribution in SNU-1 and MKN-45 cells were determined via gain-of and loss-of-function assays. The tumor growth in nude mice was also detected.

RESULTS

MiR-150, CXCL14, and NF-κB (p65) were upregulated and IRX1 was downregulated in gastric cancer tissues and cells. CXCL14 and NF-κB (p65) expression was positively related to miR-150 expression and negatively to IRX1 expression. MiR-150 inhibition and IRX1 overexpression in SNU-1 cells restricted viability, colony formation, migration, and invasion abilities, but boosted apoptosis of gastric cancer cells in vitro, and also repressed tumor growth in vivo. These results could be reversed by miR-150 elevation and IRX1 silencing, and the results from in vivo and in vitro experiments were consistent.

CONCLUSION

Our study reveals that miR-150 downregulation restrains proliferation, migration, and invasion, while facilitating apoptosis of gastric cancer cells by upregulating IRX1.

Fact or Fiction, It Is Time for a Verdict on Vasculogenic Mimicry?

The term vasculogenic mimicry (VM) refers to the capacity of certain cancer cells to form fluid-conducting structures within a tumor in an endothelial cell (EC)-free manner. Ever since its first report by Maniotis in 1999, the existence of VM has been an extremely contentious issue. The overwhelming consensus of the literature suggests that VM is frequently observed in highly aggressive tumors and correlates to lower patient survival. While the presence of VM in vivo in animal and patient tumors are claimed upon the strong positive staining for glycoproteins (Periodic Acid Schiff, PAS), it is by no means universally accepted. More controversial still is the existence of an in vitro model of VM that principally divides the scientific community. Original reports demonstrated that channels or tubes occur in cancer cell monolayers in vitro when cultured in matrigel and that these structures may support fluid movement. However, several years later many papers emerged stating that connections formed between cancer cells grown on matrigel represented VM. We speculate that this became accepted by the cancer research community and now the vast majority of the scientific literature reports both presence and mechanisms of VM based on intercellular connections, not the presence of fluid conducting tubes. In this opinion paper, we call upon evidence from an exhaustive review of the literature and original data to argue that the majority of in vitro studies presented as VM do not correspond to this phenomenon. Furthermore, we raise doubts on the validity of concluding the presence of VM in patient samples and animal models based solely on the presence of PAS+ staining. We outline the requirement for new biomarkers of VM and present criteria by which VM should be defined in vitro and in vivo.

Regulation of fibroblast-like synoviocyte transformation by transcription factors in arthritic diseases

Inflammation in the synovium is known to mediate joint destruction in several forms of arthritis. Fibroblast-like synoviocytes (FLS) are cells that reside in the synovial lining of joints and are known to be key contributors to inflammation associated with arthritis. FLS are a major source of inflammatory cytokines and catabolic enzymes that promote joint degeneration. We now know that there exists a direct correlation between the signaling pathways that are activated by the pro-inflammatory molecules produced by the FLS, and the severity of joint degeneration in arthritis. Research focused on understanding the signaling pathways that are activated by these pro-inflammatory molecules has led to major advancements in the understanding of the joint pathology in arthritis. Transcription factors (TFs) that act as downstream mediators of the pro-inflammatory signaling cascades in various cell types have been reported to play an important role in inducing the deleterious transformation of the FLS. Interestingly, recent studies have started uncovering that several TFs that were previously reported to play role in embryonic development and cancer, but not known to have pronounced roles in tissue inflammation, can actually play crucial roles in the regulation of the pathological properties of the FLS. In this review, we will discuss reports that have been able to impart novel arthritogenic roles to TFs that are specialized in embryonic development. We also discuss the therapeutic potential of targeting these newly identified regulators of FLS transformation in the treatment of arthritis.

Morphological characteristics of vasculogenic mimicry and its correlation with EphA2 expression in gastric adenocarcinoma

Genetically deregulated tumor cells generate vascular channels by vasculogenic mimicry (VM) that is independent of endothelial blood vessels. The morphological characteristics of VM and the role of EphA2 in the formation of VM were evaluated in 144 clinical samples of gastric adenocarcinoma and AGS gastric cancer cell line. It has long been believed that VM consists of PAS-positive basement membrane and CD31/CD34-negative cells. Interestingly, we found that the luminal surface of gastric tumor cells that form VM channels showed PAS-positive reaction, and that the involvement of CD31/CD34-positive tumor cells in the formation of VM channels. Highly aggressive tumor cells that formed VM were found to express CD31 or CD34, implicating the angiogenic and vasculogenic potential of the genetically deregulated tumor cells. VM occurrence was positively correlated with high expression of EphA2 in our patient cohort, and the indispensable role of EphA2 in VM formation was identified by gene silencing in AGS cells. We also report that Epstein–Barr virus (EBV)-positive tumor cells were involved in the formation of VM channels in EBV-associated gastric cancer samples. Overall, our results suggest that EphA2 signaling promotes tumor metastasis by inducing VM formation during gastric tumorigenesis.

Adipocytes fuel gastric cancer omental metastasis via PITPNC1-mediated fatty acid metabolic reprogramming

Omental metastasis occurs frequently in gastric cancer (GC) and is considered one of the major causes of gastric cancer-related mortality. Recent research indicated that omental adipocytes might mediate this metastatic predilection. Phosphatidylinositol transfer protein, cytoplasmic 1 (PITPNC1) was identified to have a crucial role in metastasis. However, whether PITPNC1 participates in the interaction between adipocytes and GC omental metastasis is unclear. Methods: We profiled and analyzed the expression of PITPNC1 through analysis of the TCGA database as well as immunohistochemistry staining using matched GC tissues, adjacent normal gastric mucosa tissues (ANTs), and omental metastatic tissues. The regulation of PITPNC1 by adipocytes was explored by co-culture systems. By using both PITPNC1 overexpression and silencing methods, the role of PITPNC1 in anoikis resistance and metastasis was determined through in vitro and in vivo experiments. Results: PITPNC1 was expressed at higher rates in GC tissues than in ANTs; notably, it was higher in omental metastatic lesions. Elevated expression of PITPNC1 predicted higher rates of omental metastasis and a poor prognosis. PITPNC1 promoted anoikis resistance through fatty acid metabolism by upregulating CD36 and CPT1B expression. Further, PITPNC1 was elevated by adipocytes and facilitated GC omental metastasis. Lastly, in vivo studies showed that PITPNC1 was a therapeutic indicator of fatty acid oxidation (FAO) inhibition. Conclusion: Elevated expression of PITPNC1 in GC is correlated with an advanced clinical stage and a poor prognosis. PITPNC1 promotes anoikis resistance through enhanced FAO, which is regulated by omental adipocytes and consequently facilitates GC omental metastasis. Targeting PITPNC1 might present a promising strategy to treat omental metastasis.

The Pattern of Signatures in Gastric Cancer Prognosis

Gastric cancer is one of the most common malignancies worldwide and it is a fourth leading cause of cancer-related death. Carcinogenesis is a multistage disease process specified by the gradual procurement of mutations and epigenetic alterations in the expression of different genes, which finally lead to the occurrence of a malignancy. These genes have diversified roles regarding cancer development. Intracellular pathways are assigned to the expression of different genes, signal transduction, cell-cycle supervision, genomic stability, DNA repair, and cell-fate destination, like apoptosis, senescence. Extracellular pathways embrace tumour invasion, metastasis, angiogenesis. Altered expression patterns, leading the different clinical responses. This review highlights the list of molecular biomarkers that can be used for prognostic purposes and provide information on the likely outcome of the cancer disease in an untreated individual.

Protein arginine methyltransferase 5-mediated epigenetic silencing of IRX1 contributes to tumorigenicity and metastasis of gastric cancer

IRX1 is originally characterized as a tumor suppressor gene of gastric cancer (GC) by our group based on serially original studies. However, the molecular regulatory mechanisms of IRX1 are not clear yet. Here, we identified protein arginine methyltransferase 5 (PRMT5) as a major upstream regulator of IRX1 for determining GC progression. Expression of PRMT5 was significantly increased in human GC tissues (433 out of 602 cases, 71.93%) compared with normal gastric mucosa, and exhibited diagnostic and prognostic potential. Overexpression of PRMT5 promoted tumorigenicity and metastasis of GC cells, while knockdown of PRMT5 abrogated tumorigenicity and metastasis of GC cells in vitro and in vivo. By co-immunoprecipitation and chromatin immunoprecipitation assays, we proved that PRMT5 elevated methylation levels of tumor suppressor IRX1 promoter via recruiting DNMT3A at promoter region. Knockdown of PRMT5 in SGC7901 and NCI-N87 cells decreased the recruitment of DNMT3A at IRX1 promoter, and reduced the methylation level of IRX1 promoter, then re-activated IRX1 expression. Whereas, overexpression of PRMT5 could epigenetically suppress IRX1 expression. Overall, PRMT5 promoted tumorigenicity and metastasis of gastric cancer cells via epigenetic silencing of IRX1. Targeting PRMT5 in GC might inhibit the malignant characters of GC and drawing a novel therapeutic potential.

HIF-2α promotes the formation of vasculogenic mimicry in pancreatic cancer by regulating the binding of Twist1 to the VE-cadherin promoter

Vasculogenic mimicry (VM) is a blood supply modality that occurs independently of endothelial cell angiogenesis. Hypoxia and the epithelial-mesenchymal transition (EMT) induce VM formation by remodeling the extracellular matrix. Our previous study demonstrated that hypoxia-inducible factor-2 alpha (HIF-2α) promotes the progress of EMT in pancreatic cancer; however, whether HIF-2α promotes VM formation in pancreatic cancer remains unknown. In this study, we investigated HIF-2α expression and VM by immunohistochemistry in 70 pancreatic cancer patients as well as the role of Twist1and Twist2 in HIF-2α-induced VM in vitro and in vivo. We found that the overexpression of HIF-2α and VM were correlated with poor tumor differentiation, late clinical stage and lymph node metastasis, and a poor prognosis in pancreatic cancer. Moreover, the upregulation of HIF-2α in SW1990 cells induced VM formation, whereas the opposite results were found after silencing HIF-2α in AsPC-1 cells. A mechanistic study indicated that HIF-2α might regulate the binding of twist1 to vascular endothelial cadherin (VE-cadherin) to promote VM formation in pancreatic cancer cells, and that the P1 (-421bp) and P4 (-2110bp) regions of the Twist1 binding sequences are positive regulatory elements for VE-cadherin. In addition, we confirmed that the overexpression of HIF-2α increased Twist1 expression and promoted tumor growth and VM formation in pancreatic cancer xenografts in nude mice. These findings indicated that HIF-2α might play a critical role in VM and that HIF-2α and the pathway of HIF-2α inducing VM formation are potential therapeutic targets for pancreatic cancer.

Genome-wide DNA methylation analysis reveals molecular subtypes of pancreatic cancer

Pancreatic cancer (PC) is the fourth leading cause of cancer deaths in the United States with a five-year patient survival rate of only 6%. Early detection and treatment of this disease is hampered due to lack of reliable diagnostic and prognostic markers. Recent studies have shown that dynamic changes in the global DNA methylation and gene expression patterns play key roles in the PC development; hence, provide valuable insights for better understanding the initiation and progression of PC. In the current study, we used DNA methylation, gene expression, copy number, mutational and clinical data from pancreatic patients. We independently investigated the DNA methylation and differential gene expression profiles between normal and tumor samples and correlated methylation levels with gene expression patterns. We observed a total of ~23-thousand differentially methylated CpG sites (Δβ≥0.1) between normal and tumor samples, where majority of the CpG sites are hypermethylated in PC, and this phenomenon is more prominent in the 5′UTRs and promoter regions compared to the gene bodies. Differential methylation is observed in genes associated with the homeobox domain, cell division and differentiation, cytoskeleton, epigenetic regulation and development, pancreatic development and pancreatic signaling and pancreatic cancer core signaling pathways. Correlation analysis suggests that methylation in the promoter region and 5′UTR has mostly negative correlations with gene expression while gene body and 3′UTR associated methylation has positive correlations. Regulatory element analysis suggests that HOX cluster and histone core proteins are upstream regulators of hypomethylation, while SMAD4, STAT4, STAT5B and zinc finger proteins (ZNF) are upstream regulators of hypermethylation. Non-negative matrix factorization (NMF) clustering of differentially methylated sites generated three clusters in PCs suggesting the existence of distinct molecular subtypes. Cluster 1 and cluster 2 showed samples enriched with clinical phenotypes like neoplasm histological grade and pathologic T-stage T3, respectively, while cluster 3 showed the enrichment of samples with neoplasm histological grade G1. To the best of our knowledge, this is the first genome-scale methylome analysis of PC data from TCGA. Our clustering analysis provides a strong basis for future work on the molecular subtyping of epigenetic regulation in pancreatic cancer.

Chitinase 3 like 1 (CHI3L1) promotes vasculogenic mimicry formation in cervical cancer

Vasculogenic mimicry (VM) is an alternative microvascular system which tumour cells orchestrate, independent of endothelial cell-mediated angiogenesis. VM develops tumour vascular networks that correlate with tumour growth, metastasis, and short survival time of patients with a number of cancers. However, little is known regarding VM in the vascularisation of cervical cancer. Chitinase 3 like 1 (CHI3L1) has been previously reported to display the ability to induce angiogenesis in cervical cancer. Here, we explored a pathological role of CHI3L1 in tumour cell-mediated vascularisation. Sixty-six samples of cervical cancer were collected to examine CHI3L1 expression and VM formation using immunohistochemistry and CD34-periodic acid-Schiff (PAS) dual staining. CHI3L1 expression was significantly correlated with formation of tumour cell-associated vascular channels in the absence of endothelial cells (p=0.031). Interestingly, tumour samples lacking VM were positively correlated with non-metastasis (p=0.035). Patients with VM positive tumours tended to have decreased overall survival (OS) compared to those with VM negative samples (43.9 versus 64.6 months, p=0.079). In addition, recombinant CHI3L1 enhanced cervical cancer cell lines to form tube-like structures, supporting the notion that CHI3L1 mediates VM in cervical cancer. Our present data reveal the crucial role of CHI3L1 in the formation of VM, which may contribute to tumour aggressiveness. Therefore, targeting CHI3L1 may be a valuable strategy for the reduction of cervical cancer vascularisation and metastasis.

Periostin promotes tumor angiogenesis in pancreatic cancer via Erk/VEGF signaling

Pancreatic cancer (PaC) consists of a bulk of stroma cells which contribute to tumor progression by releasing angiogenic factors. Recent studies have found that periostin (POSTN) is closely associate with the metastatic potential and prognosis of PaC. The purpose of this study is to determine the role of POSTN in tumor angiogenesis and explore the precise mechanisms. In this study, we used lentiviral shRNA and human recombinant POSTN protein (rPOSTN) to negatively and positively regulate POSTN expression in vitro. We found that increased POSTN expression promoted the tubule formation dependent on human umbilical vein endothelial cells (HUVECs). Moreover, knockdown of POSTN in PaC cells reduced tumor growth and VEGF expression in vivo. In accordance with these observations, we found that Erk phosphorylation and its downstream VEGF expression were upregulated achieved in rPOSTN-treated groups, opposing results were obversed in POSTN-slienced group. Meanwhile, Erk inhibitor SCH772984 significantly decreased VEGF expression as well as tubule formation of HUVECs in rPOSTN-treated PaC cells. Taken together, these findings suggest that POSTN promotes tumor angiogenesis via Erk/VEGF signaling in PaC and POSTN may be a new target for cancer anti-vascular treatment.

Clinical significance of Iroquois Homeobox Gene - IRX1 in human glioma

The present study aimed to investigate the location, expression and clinical significance of Iroquois homeobox gene (IRX1) in human glioma. The expression of IRX1 gene in glioma cell lines (U87, U373, LN229 and T98G) and normal brain tissue was detected via reverse transcription-polymerase chain reaction. The IRX1 protein in fresh glioma specimens, with the adjacent normal brain tissue, was quantified through western blotting. The archived glioma only specimens from the present hospital and glioma specimens with adjacent normal brain tissue, from Alenabio biotechnology, were subjected to immunohistochemistry and tissue microarray analysis, respectively. The Kaplan-Meier method was employed to assess the correlation between the IRX1 level and the overall survival time of the patients. IRX1 gene was demonstrated to be expressed at varying levels in U373, LN229 and T98G cells, however not in U87 cells and normal brain tissue. Western blotting revealed increased IRX1 expression in glioma tissue compared with adjacent normal brain tissue. Furthermore, a direct correlation was observed between the IRX1 expression and the clinical glioma grade, with a significant difference in the gene expression between high grade and low grade glioma (P<0.05). Notably, IRX1 was identified to be localized to the cytoplasm in the adjacent normal brain and World Health Organization grade I glioma, whereas was identified to be present in the nucleus in higher grade glioma. In addition to being established as a significant prognostic variable, IRX1 expression was positively correlated with the overall survival of glioma patients. IRX1 gene may therefore exhibit an oncogenic role in glioma condition, and thus may be of clinical importance as a future therapeutic target.

Screening and identification of potential biomarkers in triple-negative breast cancer by integrated analysis

Triple-negative breast cancer (TNBC) has attracted great attention due to its unique biology, poor prognosis, and aggressiveness. TNBC patients are more likely to suffer from metastasis. We screened and identified the TNBC-specific genes as potential biomarkers. A total of 167 breast cancer samples (45 TNBC and 122 non-TNBC) were used in the integrated analysis. Gene expression microarrays were used to screen the differentially expressed genes. We identified 65 core DEGs. According to the GO and KEGG analysis, the gene function enrichment in TNBC was revealed, such as basal cell carcinoma, prostate cancer, oocyte meiosis and choline metabolism in cancer pathways. Moreover, the PPI network reconstruction would benefit the screening of hubs. A RFS analysis of TNBC-specific genes was also conducted. RT-PCR was used to validate the expression pattern of hubs in TNBC. Finally, nine genes were identified and all of them were novel, specific and higher dysregulation expressed genes in TNBC. Such that, these genes will serve as potential biomarkers in TNBC and benefit further research in TNBC.

HMGA2 promotes vasculogenic mimicry and tumor aggressiveness by upregulating Twist1 in gastric carcinoma

High mobility group protein A2 (HMGA2) is a transcription factor that plays an important role in the invasion and metastasis of gastric carcinoma (GC). The term vasculogenic mimicry (VM) refers to the unique ability of aggressive tumour cells to mimic the pattern of embryonic vasculogenic networks. However, the relationship between HMGA2 and VM formation remains unclear. In the present study, we examined concomitant HMGA2 expression and VM in 228 human GC samples and 4 GC cell lines. Our data indicate that HMGA2 is not only significantly associated with VM formation but also influences the prognosis of patients with gastric carcinoma. Overexpression of HMGA2 significantly increased cell motility, invasiveness, and VM formation both in vitro and in vivo. A luciferase reporter assay, Co-IP and ChIP demonstrated that HMGA2 induced the expression of Twist1 and VE-cadherin by binding to the Twist1 promoter. Moreover, we observed a decrease in VE-cadherin following Twist1 knockdown in cells overexpressing HMGA2. This study indicates that HMGA2 promotes VM in GC via Twist1-VE-cadherin signalling and influences the prognosis of patients with GC.

Regional but fatal: Intraperitoneal metastasis in gastric cancer

Peritoneal carcinomatosis appears to be the most common pattern of metastasis or recurrence and is associated with poor prognosis in gastric cancer patients. Many efforts have been made to improve the survival in patients with peritoneal metastasis. Hyperthermic intraperitoneal chemotherapy remains a widely accepted strategy in the treatment of peritoneal dissemination. Several phase II-III studies confirmed that the combined cytoreducitve surgery and hyperthermic intraperitoneal chemotherapy resulted in longer survival in patients with peritoneal carcinomatosis. In addition, proper selection and effective regional treatment in patients with high risk of peritoneal recurrence after resection will further improve prognosis in local advanced gastric cancer patients.

Molecular mechanisms of peritoneal dissemination in gastric cancer

Peritoneal dissemination represents a devastating form of gastric cancer (GC) progression with a dismal prognosis. There is no effective therapy for this condition. The 5-year survival rate of patients with peritoneal dissemination is 2%, even including patients with only microscopic free cancer cells without macroscopic peritoneal nodules. The mechanism of peritoneal dissemination of GC involves several steps: detachment of cancer cells from the primary tumor, survival in the free abdominal cavity, attachment to the distant peritoneum, invasion into the subperitoneal space and proliferation with angiogenesis. These steps are not mutually exclusive, and combinations of different molecular mechanisms can occur in each process of peritoneal dissemination. A comprehensive understanding of the molecular events involved in peritoneal dissemination is important and should be systematically pursued. It is crucial to identify novel strategies for the prevention of this condition and for identification of markers of prognosis and the development of molecular-targeted therapies. In this review, we provide an overview of recently published articles addressing the molecular mechanisms of peritoneal dissemination of GC to provide an update on what is currently known in this field and to propose novel promising candidates for use in diagnosis and as therapeutic targets.

FGFR3 promotes angiogenesis-dependent metastasis of hepatocellular carcinoma via facilitating MCP-1-mediated vascular formation

The biological role of fibroblast growth factor receptor 3 (FGFR3) in tumor angiogenesis of hepatocellular carcinoma (HCC) has not been discussed before. Our previous work had indicated FGFR3 was overexpressed in HCC, and silencing FGFR3 in Hu7 cells could regulate tumorigenesis via down-regulating the phosphorylation level of key members of classic signaling pathways including ERK and AKT. In the present work, we explored the role of FGFR3 in angiogenesis-dependent metastasis by using SMMC-7721 and QGY-7703 stable cell lines. Our results indicated FGFR3 could regulate in vitro cell migration ability and in vivo lung metastasis ability of HCC, which was in accordance with increased angiogenesis ability in vitro and in vivo. Using the supernatant from SMMC-7721/FGFR3 cells, we conducted a human angiogenesis protein microarray including 43 angiogenesis factors and found that FGFR3 modulated angiogenesis and metastasis of HCC mainly by promoting the protein level of monocyte chemotactic protein 1 (MCP-1). Silencing FGFR3 by short hairpin RNA (shRNA) could reduce MCP-1 level in lysates and supernatant of QGY-7703 cells and SMMC-7721 cells. Silencing MCP-1 in QGY-7703 or SMMC-7721 cells could induce similar phenotypes compared with silencing FGFR3. Our results suggested FGFR3 promoted metastasis potential of HCC, at least partially if not all, via facilitating MCP-1-mediated angiogenesis, in addition to previously found cell growth and metastasis. MCP-1, a key medium between HCC cells and HUVECs, might be a novel anti-vascular target in HCC.

Caveolin-1 promotes tumor growth and metastasis via autophagy inhibition in hepatocellular carcinoma

BACKGROUND

Caveolin-1 is a member of the caveolae family of membrane proteins. Although some researchers have investigated the function of Caveolin-1 in hepatocellular carcinoma, the mechanism of Caveolin-1 action and its prognostic value in hepatocellular carcinoma remain unclear.

METHODS

Caveolin-1 expression was measured in hepatocellular carcinoma cell lines and tissues using quantitative reverse transcription-polymerase chain reaction, western blot, and immunofluorescence assays. In in vitro experiments, Caveolin-1 was depleted using a short hairpin RNA lentiviral vector, and tumor cell behavior was analyzed. The effect of Caveolin-1 on hepatocellular carcinoma cell autophagy was investigated. Prognostic value of Caveolin-1 was analyzed by immunohistochemistry in two cohorts that included a total of 721 hepatocellular carcinoma patients.

RESULTS

We found that Caveolin-1 was overexpressed in highly metastatic hepatocellular carcinoma cell lines and tumor tissues. Moreover, Caveolin-1 promoted hepatocellular carcinoma cell proliferation, migration, and angiogenesis and inhibited autophagy. Finally, Caveolin-1 expression in hepatocellular carcinoma tissues was inversely correlated with patient overall survival and time to recurrence.

CONCLUSION

Our data obtained from cell lines suggest an oncogenic role for Caveolin-1 in hepatocellular carcinoma, Caveolin-1 contributed to hepatocellular carcinoma cell autophagy deficiency. Furthermore, Caveolin-1 may function as a novel prognostic indicator for hepatocellular carcinoma patients after curative resection, and combination of targeted therapy aimed at Caveolin-1 and autophagy modulation may represent an effective way to treat hepatocellular carcinoma.

Metastasis-associated in colon cancer-1 promotes vasculogenic mimicry in gastric cancer by upregulating TWIST1/2

Vasculogenic mimicry (VM) is a blood supply modality that is strongly associated with the epithelial-mesenchymal transition (EMT), TWIST1 activation and tumor progression. We previously reported that metastasis-associated in colon cancer-1 (MACC1) induced the EMT and was associated with a poor prognosis of patients with gastric cancer (GC), but it remains unknown whether MACC1 promotes VM and regulates the TWIST signaling pathway in GC. In this study, we investigated MACC1 expression and VM by immunohistochemistry in 88 patients with stage IV GC, and also investigated the role of TWIST1 and TWIST2 in MACC1-induced VM by using nude mice with GC xenografts and GC cell lines. We found that the VM density was significantly increased in the tumors of patients who died of GC and was positively correlated with MACC1 immunoreactivity (p < 0.05). The 3-year survival rate was only 8.6% in patients whose tumors showed double positive staining for MACC1 and VM, whereas it was 41.7% in patients whose tumors were negative for both MACC1 and VM. Moreover, nuclear expression of MACC1, TWIST1, and TWIST2 was upregulated in GC tissues compared with matched adjacent non-tumorous tissues (p < 0.05). Overexpression of MACC1 increased TWIST1/2 expression and induced typical VM in the GC xenografts of nude mice and in GC cell lines. MACC1 enhanced TWIST1/2 promoter activity and facilitated VM, while silencing of TWIST1 or TWIST2 inhibited VM. Hepatocyte growth factor (HGF) increased the nuclear translocation of MACC1, TWIST1, and TWIST2, while a c-Met inhibitor reduced these effects. These findings indicate that MACC1 promotes VM in GC by regulating the HGF/c-Met-TWIST1/2 signaling pathway, which means that MACC1 and this pathway are potential new therapeutic targets for GC.

DBGC: A Database of Human Gastric Cancer

The Database of Human Gastric Cancer (DBGC) is a comprehensive database that integrates various human gastric cancer-related data resources. Human gastric cancer-related transcriptomics projects, proteomics projects, mutations, biomarkers and drug-sensitive genes from different sources were collected and unified in this database. Moreover, epidemiological statistics of gastric cancer patients in China and clinicopathological information annotated with gastric cancer cases were also integrated into the DBGC. We believe that this database will greatly facilitate research regarding human gastric cancer in many fields. DBGC is freely available at http://bminfor.tongji.edu.cn/dbgc/index.do

CEACAM6 promotes tumor angiogenesis and vasculogenic mimicry in gastric cancer via FAK signaling

CEACAM6 is a member of glycosylphosphatidylinositol-linked immunoglobulin superfamily that is implicated in a variety of human cancers. In our previous study, we reported that CEACAM6 was overexpressed in gastric cancer tissues and promoted cancer metastasis. The purpose of this study is to determine the role of CEACAM6 in tumor angiogenesis and mimicry formation. We found that overexpressed CEACAM6 promoted tubule formation dependent on HUVEC cells and vasculogenic mimicry formation of gastric cancer cells; opposing results were achieved in CEACAM6-silenced groups. Moreover, we found that mosaic vessels formed by HUVEC cells and gastric cancer cells were observed in vitro by 3D-culture assay. Overexpressed CEACAM6 in gastric cancer cells promoted tumor growth, VEGF expression and vasculogenic mimicry structures formation in vivo. In accordance with these observations, we found that phosphorylation of FAK and phosphorylation of paxillin were up-regulated in CEACAM6-overexpressing gastric cancer cells, and FAK inhibitor Y15 could reduce tubule and vasculogenic mimicry formation. These findings suggest that CEACAM6 promotes tumor angiogenesis and vasculogenic mimicry formation via FAK signaling in gastric cancer and CEACAM6 may be a new target for cancer anti-vascular treatment.

Advanced research on vasculogenic mimicry in cancer

Vasculogenic mimicry (VM) is a brand-new tumour vascular paradigm independent of angiogenesis that describes the specific capacity of aggressive cancer cells to form vessel-like networks that provide adequate blood supply for tumour growth. A variety of molecule mechanisms and signal pathways participate in VM induction. Additionally, cancer stem cell and epithelial-mesenchymal transitions are also shown to be implicated in VM formation. As a unique perfusion way, VM is associated with tumour invasion, metastasis and poor cancer patient prognosis. Due to VM's important effects on tumour progression, more VM-related strategies are being utilized for anticancer treatment. Here, with regard to the above aspects, we make a review of advanced research on VM in cancer.

Republished: tracing PAKs from GI inflammation to cancer

P-21 activated kinases (PAKs) are effectors of Rac1/Cdc42 which coordinate signals from the cell membrane to the nucleus. Activation of PAKs drive important signalling pathways including mitogen activated protein kinase, phospoinositide 3-kinase (PI3K/AKT), NF-κB and Wnt/β-catenin. Intestinal PAK1 expression increases with inflammation and malignant transformation, although the biological relevance of PAKs in the development and progression of GI disease is only incompletely understood. This review highlights the importance of altered PAK activation within GI inflammation, emphasises its effect on oncogenic signalling and discusses PAKs as therapeutic targets of chemoprevention.

Tracing PAKs from GI inflammation to cancer

P-21 activated kinases (PAKs) are effectors of Rac1/Cdc42 which coordinate signals from the cell membrane to the nucleus. Activation of PAKs drive important signalling pathways including mitogen activated protein kinase, phospoinositide 3-kinase (PI3K/AKT), NF-κB and Wnt/β-catenin. Intestinal PAK1 expression increases with inflammation and malignant transformation, although the biological relevance of PAKs in the development and progression of GI disease is only incompletely understood. This review highlights the importance of altered PAK activation within GI inflammation, emphasises its effect on oncogenic signalling and discusses PAKs as therapeutic targets of chemoprevention.

Interaction between gastric cancer stem cells and the tumor microenvironment

Gastric cancer (GC) remains a leading cause of cancer-related deaths worldwide. Cancer stem cells (CSCs) are selectively capable of tumor initiation and are implicated in tumor relapse and metastasis, thus, governing the prognosis of GC patients. Stromal cells and extracellular matrix adjacent to cancer cells are known to form a supportive environment for cancer progression. CSC properties are also regulated by their microenvironment through cell signaling and related factors. This review presents the current findings regarding the influence of the tumor microenvironment on GC stem cells, which will support the development of novel therapeutic strategies for patients with GC.

Tumour vasculogenic mimicry is associated with poor prognosis of human cancer patients: a systemic review and meta-analysis

BACKGROUND

Vasculogenic mimicry (VM) has been reported in various malignant tumours and is known to play an important role in cancer progression and metastasis. However, the impact of VM on the overall survival of human cancer patients remains controversial. The goal of this study was to evaluate whether VM is associated with 5-year survival of human cancer patients.

METHODS

Twenty-two eligible clinical studies with data on both tumour cell-dominant VM and the 5-year survival of 3062 patients involved in 15 types of cancers were pooled in the meta-analysis.

RESULTS

The 5-year overall survival of VM-positive and -negative cancer patients was 31% and 56%, respectively. The relative risk (RR) of the 5-year survival of VM-positive patients was significantly higher than that of VM-negative cases (RR=1.531; 95% confidence interval (CI): 1.357-1.726; P<0.001). Notably, metastatic melanoma patients demonstrated a higher VM rate (45.3%) than patients with primary melanoma (23.1%) and showed worse 5-year survival, suggesting that VM contributes to tumour metastasis and poor prognosis in cancer patients. Subgroup analysis indicated that a poor 5-year survival was significantly associated with eight types of VM-positive malignant tumours, such as lung, colon, liver cancers, sarcomas and melanoma; but was not associated with the seven other types of cancers, such as prostate cancer. Heterogeneity and publication biases were found among the 22 studies, mainly due to the divergent characteristics of cancers and extremely low survival rate in six types of malignant tumours.

CONCLUSION

VM-positive cancer patients show a poor 5-year overall survival compared with VM-negative malignant tumour cases, particularly in metastatic cancer.

VEZT, a novel putative tumor suppressor, suppresses the growth and tumorigenicity of gastric cancer

Vezatin (VEZT), an adherens junctions transmembrane protein, was identified as a putative tumor suppressor in our previous study. However, the role of VEZT in tumorigenesis remains elusive. We aimed to clarify its epigenetic regulation and biological functions in gastric cancer. In this study, we show that the expression level of VEZT is involved in lymphatic metastasis, depth of cancer invasion and TNM stage in 104 gastric cancer patients. Bisulfate sequencing polymerase chain reaction (BSP) methods showed that VEZT was hypermethylated in tissues and corresponding blood of gastric cancer patients compared with healthy controls. Helicobacter pylori (H. pylori) infection induces the methylation and silencing of VEZT in GES-1 cells. Restoring VEZT expression in MKN-45 and NCI-N87 gastric cancer cells inhibited growth, invasion and tumorigenesis in vitro and in vivo. Global microarray analysis was applied to analyze the molecular basis of the biological functions of VEZT after VEZT transfection combined with real-time PCR and chromatin immunoprecipitation assay. G protein-coupled receptor 56(GPR56), cell growth, cell division cycle 42(CDC42), migration/invasion and transcription factor 19(TCF19), cell cycle progression, were identified as direct VEZT target genes. TCF19, a novel target of VEZT, was functionally validated. Overexpression of TCF19 in MKN-45 cells increased cell cycle progress and growth ability. This study provides novel insight into the regulation of the VEZT gene, which could represent a potential target for therapeutic anti-cancer strategies.

Tumor cell-mediated neovascularization and lymphangiogenesis contrive tumor progression and cancer metastasis

Robust neovascularization and lymphangiogenesis have been found in a variety of aggressive and metastatic tumors. Endothelial sprouting angiogenesis is generally considered to be the major mechanism by which new vasculature forms in tumors. However, increasing evidence shows that tumor vasculature is not solely composed of endothelial cells (ECs). Some tumor cells acquire processes similar to embryonic vasculogenesis and produce new vasculature through vasculogenic mimicry, trans-differentiation of tumor cells into tumor ECs, and tumor cell-EC vascular co-option. In addition, tumor cells secrete various vasculogenic factors that induce sprouting angiogenesis and lymphangiogenesis. Vasculogenic tumor cells actively participate in the formation of vascular cancer stem cell niche and a premetastatic niche. Therefore, tumor cell-mediated neovascularization and lymphangiogenesis are closely associated with tumor progression, cancer metastasis, and poor prognosis. Vasculogenic tumor cells have emerged as key players in tumor neovascularization and lymphangiogenesis and play pivotal roles in tumor progression and cancer metastasis. However, the mechanisms underlying tumor cell-mediated vascularity as they relate to tumor progression and cancer metastasis remain unclear. Increasing data have shown that various intrinsic and extrinsic factors activate oncogenes and vasculogenic genes, enhance vasculogenic signaling pathways, and trigger tumor neovascularization and lymphangiogenesis. Collectively, tumor cells are the instigators of neovascularization. Therefore, targeting vasculogenic tumor cells, genes, and signaling pathways will open new avenues for anti-tumor vasculogenic and metastatic drug discovery. Dual targeting of endothelial sprouting angiogenesis and tumor cell-mediated neovascularization and lymphangiogenesis may overcome current clinical problems with anti-angiogenic therapy, resulting in significantly improved anti-angiogenesis and anti-cancer therapies.

Cancer stem cells: the 'heartbeat' of gastric cancer

Gastric cancer (GC) remains one of the most common cancers worldwide. Its prevalence is still on the rise in the developing countries due to the ageing population. The cancer stem cell (CSC) theory provides a new insight into the interpretation of tumor initiation, aggressive growth, recurrence, and metastasis of cancer, as well as the development of new strategies for cancer treatment. This review will focus on the progress of biomarkers and signaling pathways of CSCs, the complex crosstalk networks between the microenvironment and CSCs, and the development of therapeutic approaches against CSCs, predominantly focusing on GC.