Role of TGF-beta1, its receptor TGFbetaRII, and Smad proteins in the progression of colorectal cancer

Recent advances and molecular mechanisms of TGF-β signaling in colorectal cancer, with focus on bioactive compounds targeting

Colorectal cancer (CRC) is one of the most significant forms of human cancer. It is characterized by its heterogeneity because several molecular factors are involved in contiguity and can link it to others without having a linear correlation. Among the factors influencing tumor transformation in CRC, transforming growth factor-beta (TGF-β) plays a key promoter role. This factor is associated with human colorectal tumors with a very high prognosis: it increases the survival, invasion, and metastasis of CRC cells, thus functioning as an oncogene. The inhibition of this factor can constitute a major therapeutic route for CRC treatment. Various chemical drugs including synthetic molecules and biotherapies have been developed as TGF-β inhibitors. Moreover, the scientific community has recently shown a major interest in screening natural drugs inhibiting TGF-β in CRC. In this context, we carried out this review article using computerized databases, such as PubMed, Google Scholar, Springer Link, Science Direct, Cochrane Library, Embase, Web of Science, and Scopus, to highlight the molecular mechanism of TGF-β in CRC induction and progression and current advances in the pharmacodynamic effects of natural bioactive substances targeting TGF-β in CRC.

RNA-Interference-Mediated miR-122-Based Gene Regulation in Colon Cancer, a Structural In Silico Analysis

The role of microRNA 122 (miR-122) in colorectal cancer (CRC) has not been widely investigated. In the current study, we aimed to identify the prominent gene and protein interactors of miR122 in CRC. Based on their binding affinity, these targets were chosen as candidate genes for the creation of miR122-mRNA duplexes. Following this, we examined the miRNA-mediated silencing mechanism using the gene-silencing complex protein Argonaute (AGO). Public databases, STRING, and GeneMANIA were utilized to identify major proteins and genes interacting with miR-122. DAVID, PANTHER, UniProt, FunRich, miRwalk, and KEGG were used for functional annotation, pathway enrichment, binding affinity analysis, and expression of genes in different stages of cancer. Three-dimensional duplexes of hub genes and miR-122 were created using the RNA composer, followed by molecular interaction analysis using molecular docking with the AGO protein. We analyzed, classified, and scrutinized 93 miR-122 interactors using various bioinformatic approaches. A total of 14 hub genes were categorized as major interactors of miR-122. The study confirmed the role of various experimentally documented miR-122 interactors such as MTDH (Q86UE4), AKT1 (P31749), PTPN1 (P18031), MYC (P01106), GSK3B (P49841), RHOA (P61586), and PIK3CG (P48736) and put forth several novel interactors, with AKT3 (Q9Y243), NCOR2 (Q9Y618), PIK3R2 (O00459), SMAD4 (P61586), and TGFBR1 (P36897). Double-stranded RNA duplexes of the strongest interactors were found to exhibit higher binding affinity with AGO. In conclusions, the study has explored the role of miR-122 in CRC and has identified a closely related group of genes influencing the prognosis of CRC in multiple ways. Further, these genes prove to be targets of gene silencing through RNA interference and might serve as effective therapeutic targets in understanding and treating CRC.

Tumor-associated macrophages improve hypoxia-induced endoplasmic reticulum stress response in colorectal cancer cells by regulating TGF-β1/SOX4

Hypoxia is a common feature of solid tumors that can induce endoplasmic reticulum stress (ERS). This study aimed to explore the mechanism behind tumor-associated macrophages (TAMs) improving the ERS response of colorectal cancer (CRC) under hypoxic conditions. Herein, it was demonstrated that TAMs reduce ERS by secreting TGF-β1 and activating SOX4/TMEM2 signaling in CRC cells. The expression levels of TGF-β1, SOX4, and TMEM2 in 20 pairs of tumor tissues and para-carcinoma tissues were assessed. A co-culture system of CRC cells with THP-1-derived macrophages under hypoxic conditions in vitro was investigated to determine the protective effect of TAMs on CRC cells. Moreover, to further verify the underlying mechanism, TGF-β1 and SOX4 were knocked down in the TAMs and CRC cells, respectively. The results exposed that TGF-β1, SOX4, and TMEM2 were abundantly expressed in tumor tissues. Moreover, the co-culture system revealed that macrophages stimulate TGF-β1 secretion under hypoxia, which depresses the CRC cells' ERS, further promoting cell proliferation and inhibiting apoptosis. Furthermore, increased TGF-β1 levels promoted the expression of SOX4 and TMEM2 in CRC cells. Conversely, the knockdown of SOX4 attenuated the protective effect of TAMs on TGF-β1-stimulated CRC cells. In conclusion, these results suggest that the elevated ERS induced by hypoxia in CRC cells could be relieved by TAMs via the secretion of TGF-β1. Finally, TGF-β1 suppresses undue ERS response in CRC cells by activating the SOX4-TMEM2 axis.

The Therapeutic Potential of Tackling Tumor-Induced Dendritic Cell Dysfunction in Colorectal Cancer

Colorectal cancer (CRC) is the third most diagnosed malignancy and the second leading cause of cancer-related deaths worldwide. Locally advanced and metastatic disease exhibit resistance to therapy and are prone to recurrence. Despite significant advances in standard of care and targeted (immuno)therapies, the treatment effects in metastatic CRC patients have been modest. Untreatable cancer metastasis accounts for poor prognosis and most CRC deaths. The generation of a strong immunosuppressive tumor microenvironment (TME) by CRC constitutes a major hurdle for tumor clearance by the immune system. Dendritic cells (DCs), often impaired in the TME, play a critical role in the initiation and amplification of anti-tumor immune responses. Evidence suggests that tumor-mediated DC dysfunction is decisive for tumor growth and metastasis initiation, as well as for the success of immunotherapies. Unravelling and understanding the complex crosstalk between CRC and DCs holds promise for identifying key mechanisms involved in tumor progression and spread that can be exploited for therapy. The main goal of this review is to provide an overview of the current knowledge on the impact of CRC-driven immunosuppression on DCs phenotype and functionality, and its significance for disease progression, patient prognosis, and treatment response. Moreover, present knowledge gaps will be highlighted as promising opportunities to further understand and therapeutically target DC dysfunction in CRC. Given the complexity and heterogeneity of CRC, future research will benefit from the use of patient-derived material and the development of in vitro organoid-based co-culture systems to model and study DCs within the CRC TME.

SMAD4 Expression in Renal Cell Carcinomas Correlates With a Stem-Cell Phenotype and Poor Clinical Outcomes

Renal cell carcinoma (RCC) is the most lethal neoplasm of common urologic cancers with poor prognoses. SMAD4 has a principal role in TGF-β (Transformis growth factorβ)-induced epithelial to mesenchymal transition (EMT) as a key factor in gaining cancer stem cell (CSC) features and tumor aggressiveness. This study aimed to evaluate the expression patterns and clinical significance of SMAD4 in RCC and the impact of its targeting on stem cell/mesenchymal cells and EMT characteristics in renal spheroid derived cells (SDCs) compared to parental cells (PCs) in RCC. The expression pattern and clinical significance of SMAD4 was evaluated in RCC. SDCs were enriched using a sphere culture system. Then SDCs and their PCs were compared with respect to their sphere and colony formation, expression of putative CSC markers, invasiveness as well as expression of genes, including stemness/mesenchymal, SMAD4 and TGFβ1genes. Finally, the effect of SMAD4 knockdown on SDCs was analyzed. We demonstrated that SMAD4 is positively correlated with decreased disease specific survival (DSS) in RCC patients and clear cell RCC (ccRCC) subtype and associates with poor DSS in patients with RCC, especially in ccRCC as the most metastatic RCC subtype. SDCs exhibited higher stem cell/mesenchymal properties. Inhibition of SMAD4 in PCs accelerated the dissociation of SDCs and decreased their clonogenicity, invasiveness, expression of mesenchymal markers and expression of SMAD4 and TGFβ1 genes compared to SDCs before transfection. We suggest that targeting SMAD4 may be useful against renal CSCs and may improve RCC prognosis.

A Negative Feedback Loop Between NAMPT and TGF-β Signaling Pathway in Colorectal Cancer Cells

Background

Nicotinamide phosphoribosyltransferase (NAMPT) and the transforming growth factor-β (TGF-β) signaling pathway play important roles in colorectal tumorigenesis and progress. However, the underlying regulatory mechanisms between NAMPT and TGF-β signaling in colorectal cancer (CRC) remain poorly understood.

Methods

Public data were extracted from the Oncomine database and the PrognoScan database to investigate the mRNA expression and the prognostic value of NAMPT, respectively, in CRC. Western blot tests were performed to detect Smad2, Smad3, p-Smad2, p-Smad3, Smad4 expression in CRC cells transfected with human NAMPT-siRNA or NAMPT-overexpressing plasmid. TGF-β1 concentrations in culture supernatants were assayed using ELISA kits. The effect of TGF-β1 on NAMPT expression was evaluated by quantitative real-time PCR and Western blot. The dual-luciferase reporter assay was employed to confirm the binding of miR-1-3p to NAMPT 3ʹ-UTR. Subsequently, NAMPT levels in HCT116 cells transfected with the mimics and inhibitors of miR-1-3p were detected by quantitative real-time PCR and Western blot.

Results

NAMPT was overexpressed in human CRC and was correlated with short overall survival. NAMPT increased the protein expression levels of components in the TGF-β signaling pathway including Smad2, Smad3, and Smad4. Moreover, NAMPT promoted TGF-β1 secretion. Intriguingly, the TGF-β1 treatment down-regulated NAMPT expression at mRNA and protein levels in CRC cells which were partly through the up-regulation of miR-1-3p that directly bound to the NAMPT 3ʹ-UTR. These outcomes demonstrated that NAMPT was a downstream target of miR-1-3p and there was a negative association between NAMPT and miR-1-3p in CRC.

Conclusion

There is a negative feedback loop between NAMPT and the TGF-β signaling pathway in CRC cells, providing new insight into the mechanism underlying the regulatory pathways in CRC.

Silencing of lncRNA EZR-AS1 inhibits proliferation, invasion, and migration of colorectal cancer cells through blocking transforming growth factor β signaling

Long non-coding RNA (lncRNA) plays a key regulatory role in the pathogenesis of colorectal cancer (CRC). In the present study, the specific regulatory role of lncRNA ezrin antisense RNA 1 (EZR-AS1) on CRC was investigated. The expression of lncRNA EZR-AS1 was significantly up-regulated in CRC cell lines (HCT8, HCT116, HT29, and SW620 cells), which was significantly different from that of normal human fetal colonic mucosa cells (FHC cells) (P<0.01). HCT116 and HT29 cells were then transfected with EZR-AS1 shRNA (sh-EZR-AS1) to silence lncRNA EZR-AS1 (P<0.01). When compared with the Control, after transfection of SH-EZR-AS1, E-cadherin was up-regulated, Vimentin was down-regulated, the apoptosis rate was increased, the cell viability, wound healing rate, and the number of invasive cells were decreased in HCT116 and HT29 cells (P<0.05). Silencing of lncRNA EZR-AS also significantly reduced the tumor volume and weight in mice injected with sh-EZR-AS1-transfected HCT116 and HT29 cells (P<0.05). The regulatory relationship between lncRNA EZR-AS1 and transforming growth factor β (TGF-β) signaling was further identified in CRC cells. Silencing of lncRNA EZR-AS1 significantly down-regulated TGF-β, Smad2, and α-SMA expression in HCT116 and HT29 cells at the protein level (P<0.05). The intervention of SB431542 (a TGF-β receptor blocker) and silencing of Smad2 both significantly down-regulated lncRNA EZR-AS1 expression in HCT116 and HT29 cells (P<0.01). In conclusion, silencing of lncRNA EZR-AS1 inhibited the proliferation, invasion, migration, and epithelial–mesenchymal transition, and promoted the apoptosis of CRC cells through blocking TGF-β signaling.

Activation of Slit2/Robo1 Signaling Promotes Tumor Metastasis in Colorectal Carcinoma through Activation of the TGF-β/Smads Pathway

Slit2 (slit guidance ligand 2), a ligand of the Roundabout1 (Robo1) transmembrane receptor, is often overexpressed in colorectal carcinomas (CRCs). In this study, we performed data mining in the Metabolic gEne RApid Visualizer (MERAV) database and found that Slit2 and TGF-β1 (Transforming growth factor-β1) are highly expressed in carcinomas relative to those in tumor-free tissues from healthy volunteers or wild type mice. Furthermore, expression of Slit2 and TGF-β1 in CRCs increases with pathological stages. Serum levels of Slit2 in patients with CRC and in ApcMin/+ mice with spontaneous intestinal adenoma were significantly increased compared with those in healthy controls. Specific blockage of Slit2 binding to Robo1 inactivated TGF-β/Smads signaling and inhibited tumor cell migration and metastasis, which can be partially restored by treatment with TGF-β1. However, specific inhibition of TGF-β1/Smads signaling reduced CRC tumor cell migration and invasion without affecting cell proliferation. This study suggests that activation of Slit2/Robo1 signaling in CRC induces tumor metastasis partially through activation of the TGF-β/Smads pathway.

Clinicopathological Characterization and Prognostic Implication of SMAD4 Expression in Colorectal Carcinoma

Background

SMAD family member 4 (SMAD4) has gained attention as a promising prognostic factor of colorectal cancer (CRC) as well as a key molecule to understand the tumorigenesis and progression of CRC.

Methods

We retrospectively analyzed 1,281 CRC cases immunohistochemically for their expression status of SMAD4, and correlated this status with clinicopathologic and molecular features of CRCs.

Results

A loss of nuclear SMAD4 was significantly associated with frequent lymphovascular and perineural invasion, tumor budding, fewer tumor-infiltrating lymphocytes, higher pT and pN category, and frequent distant metastasis. In contrast, tumors overexpressing SMAD4 showed a significant association with sporadic microsatellite instability. After adjustment for TNM stage, tumor differentiation, adjuvant chemotherapy, and lymphovascular invasion, the loss of SMAD4 was found to be an independent prognostic factor for worse 5-year progression-free survival (hazard ratio [HR], 1.27; 95% confidence interval [CI], 1.01 to 1.60; p=.042) and 7-year cancer-specific survival (HR, 1.45; 95% CI, 1.06 to 1.99; p=.022).

Conclusions

We confirmed the value of determining the loss of SMAD4 immunohistochemically as an independent prognostic factor for CRC in general. In addition, we identified some histologic and molecular features that might be clues to elucidate the role of SMAD4 in colorectal tumorigenesis and progression.

Ginsenoside Rb2 inhibits epithelial-mesenchymal transition of colorectal cancer cells by suppressing TGF-β/Smad signaling

BACKGROUND

Treating colorectal cancer (CRC) continues to be a clinical challenge. Studies have shown that epithelial-mesenchymal transition (EMT) is a critical step in tumor progression and transforming growth factor-β1 (TGF-β1) signaling has been shown to play a crucial role in EMT. Here, we investigate the inhibition effect of Ginsenoside Rb2, main bioactive component of ginseng, in human colorectal cancer cells via TGF-β1.

PURPOSE

The current study aims to study the inhibitory effect of Ginsenoside Rb2 on HCT116 and SW620 cells and its anti-tumor mechanism.

METHODS

Histomorphological analysis and western blot analysis were performed to evaluate expression of TGF-β1 in human cancerous colon samples and the adjacent normal samples. The docking simulation assay were performed to explore the potential mode of binding of Ginsenoside Rb2 to the TGF-β1 protein. CCK8, adhesion and invasion assay were used to assess the effects of Ginsenoside Rb2 in HCT116 and SW620 cells. RT-PCR, Western blot and Immunohistochemical staining were employed to detect the TGF-β1-related signaling pathways in the colon cancer cells and/or xenograft mice.

RESULTS

The expression of TGF-β1 in human cancerous colon samples was significantly increased compared with the adjacent normal samples. Ginsenoside Rb2 inhibit the growth, adhesion, EMT and metastasis of human colorectal cancer cells. The docking simulation assay confirmed that Ginsenoside Rb2 bound to the hydrophobic pocket of TGF-β1, which partially overlaps with the binding sites on TGF-β1, and thus disrupted TGF-β1 dimerization. Western Blot analysis further confirmed that Ginsenoside Rb2 could inhibit the expression of TGF-β1 in vitro and in vivo. Furthermore, Ginsenoside Rb2 could inhibit the expression of Smad4 and phosphorylated Smad2/3.

CONCLUSION

Ginsenoside Rb2 could inhibit EMT of colorectal cancer cells through the TGF-β1/Smad signaling, and might be a potential candidate for the treatment of colorectal cancer.

Celastrol inhibits colorectal cancer through TGF-β1/Smad signaling

BACKGROUND

There are few clinical challenges associated with the treatment of colorectal cancer (CRC). Studies have shown that TGF-β plays a crucial role in CRC. Importantly, celastrol, a major components of the root extract of the traditional Chinese herb Tripterygium wilfordii Hook F, has been shown to inhibit the growth, adhesion, and metastasis of human CRC cells through the inhibition of TGF-β1/Smad signaling.

MATERIALS AND METHODS

Real-time PCR and Western blot tests were proceeded to present TGF-β1, TGF-β receptor type I (TGFβRI), TGF-β receptor type II (TGFβRII), Smad2/3, p-Smad2/3, Smad4, and glyceraldehyde-3-phosphate dehydrogenase expression in human colon cancer cell samples.

RESULTS

Our results indicated that celastrol can reduce the expression levels of TGF-β1, TGFβRI, and TGFβRII in HCT116 and SW620 cells. Furthermore, celastrol could also prevent the increase in Smad4 and p-Smad2/3 in HCT116 and SW620 cells.

CONCLUSION

Celastrol could inhibit tumor growth through TGF-β1/Smad signaling and might be a promising therapeutic component against CRC.

Role of the transforming growth factor-β signaling pathway in the pathogenesis of colorectal cancer

The transforming growth factor-β (TGF-β) signaling pathway plays an important role in cancer cell proliferation, growth, metastasis, and apoptosis. It has been shown that TGF-β acts as a tumor suppressor in the early stages of the disease, and as a tumor promoter in its late stages. Mutations in the TGF-β signaling components, the TGF-β receptors and cytoplasmic signaling transducers, are frequently observed in colorectal carcinomas. Exploiting specific TGF-β receptor agonist and antagonist with antitumor properties may be a way of controlling cancer progression. This review summarizes the regulatory role of TGF-β signaling in the pathogenesis of colorectal cancer.

HOXC6 gene silencing inhibits epithelial-mesenchymal transition and cell viability through the TGF-β/smad signaling pathway in cervical carcinoma cells

Background

Homeobox C6 (HOXC6) plays a part in malignant progression of some tumors. However, the expression of HOXC6 and its clinical significance remains unclear in cervical carcinoma (CC). The purpose of this study is to verify the effects of HOXC6 gene silencing on CC through the TGF-β/smad signaling pathway.

Methods

CC tissues and corresponding paracancerous tissues were collected from CC patients with involvement of a series of HOXC6-siRNA, HA-HOXC6 and the TGF-β/smad pathway antagonist. HOXC6 expression was analyzed in six CC cell lines (C-33A, HeLa, CaSki, SiHa, ME-180, and HCC-94) by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The mRNA and protein expression of HOXC6, TGF-β1, TGF-β RII, smad4, smad7, E-cadherin, N-cadherin, Vimentin, ki-67, proliferating cell nuclear antigen (PCNA), p27, and Cyclin D1 were determined by RT-qPCR and western blot analysis. Cell proliferation, apoptosis and cell cycle were detected by MTT assay and flow cytometry, respectively.

Results

Higher positive expression rate of HOXC6 protein was observed in CC tissues and HOXC6 was related to TNM stage, lymphatic metastasis, cancer types, primary lesion diameter, and histological grade of CC. Silencing HOXC6 inhibited epithelial-mesenchymal transition (EMT) (shown as decreased N-cadherin and Vimentin, and increased E-cadherin) through the inactivation of the TGF-β/smad signaling pathway. HOXC6 gene silencing hindered cell proliferation and accelerated cell apoptosis of CC cells. Furthermore, the effect of HOXC6 silencing was enhanced when the TGF-β/smad signaling pathway was suppressed.

Conclusion

The results reveal that HOXC6 gene silencing may inhibit EMT event and cell viability in CC through the inhibition of the activation of TGF-β/smad signaling pathway.

Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk

Colorectal cancer (CRC) is one of the leading cancers throughout the world. It represents the third most common cancer and the fourth in mortality. Most of CRC are sporadic, arise with no known high-penetrant genetic variation and with no previous family history. The etiology of sporadic CRC is considered to be multifactorial and arises from the interaction of genetic variants of low-penetrant genes and environmental risk factors. The most common well-studied genetic variation is single nucleotide polymorphisms (SNPs). SNP arises as a point mutation. If the frequency of the sequence variation reaches 1% or more in the population, it is referred to as polymorphism, but if it is lower than 1%, the allele is typically considered as a mutation. Lots of SNPs have been associated with CRC development and progression, for example, genes of TGF-β1 and CHI3L1 pathways. TGF-β1 is a pleiotropic cytokine with a dual role in cancer development and progression. TGF-β1 mediates its actions through canonical and noncanonical pathways. The most important negative regulatory protein for TGF-β1 activity is termed SMAD7. The production of TGF-β can be controlled by another protein called YKL-40. YKL-40 is a glycoprotein with an important role in cancer initiation and metastasis. YKL-40 is encoded by the CHI3L1 gene. The aim of the present review is to give a brief introduction of CRC, SNP, and examples of some SNPs that have been documented to be associated with CRC. We also discuss two important signaling pathways TGF-β1 and CHI3L1 that influence the incidence and progression of CRC.

Tumor budding and human chorionic gonadotropin-β expression correlate with unfavorable patient outcome in colorectal carcinoma

Tumor budding is thought to represent a manifestation of epithelial-to-mesenchymal transition (EMT) and it has been correlated with poor patient outcomes in colorectal cancer (CRC). Our group recently demonstrated that human chorionic gonadotropin-β (hCGβ) modulates EMT in CRC. In the current study, based on the likely relationships between tumor budding and hCGβ expression, we examined their clinicopathologic significance in CRC. Twenty-eight of 80 (35.0%) CRC showed tumor budding. Tumor budding significantly correlated with lymph node metastasis (P < 0.01), pathologic stage (P < 0.01), lymphatic invasion (P = 0.044), and vascular invasion (P = 0.013). Thirteen of 80 (16.3%) CRC were hCGβ positive on immunohistochemistry. More tumor buds were present in the hCGβ-positive cases (P < 0.01), and tumor budding was significantly correlated with hCGβ positivity (P < 0.01). Cases with both tumor budding and hCGβ expression had the poorest prognosis compared with all other groups (P < 0.01). In conclusion, tumor budding and hCGβ expression are closely associated with EMT, and they are independent prognostic factors in CRC. They identify patients with an "EMT phenotype" who may respond to targeted molecular therapies.

Chorionic Gonadotropin-β Modulates Epithelial-Mesenchymal Transition in Colorectal Carcinoma Metastasis

Ectopic production of free β human chorionic gonadotropin (hCGβ) has been associated with aggressive behavior in non-trophoblastic tumors. hCGβ shares common evolutionary sequences with transforming growth factor-β (TGF-β), which represents a major driving force of epithelial-to-mesenchymal transition (EMT). In this study, we examined the biological roles of hCGβ during EMT and its clinical significance in colorectal cancer (CRC) progression. Eighty CRC specimens and 54 preoperative serum samples were analyzed. hCGβ-overexpressing human CRC cell lines were examined for invasiveness and tumorigenicity, and the expression of EMT-associated genes was investigated. In human CRC, histologic hCGβ positivity [13/80 (16.3%)] was lower than serologic hCGβ positivity [13/54 (24.1%)]. However, it was significantly correlated with several clinicopathological features and unfavorable outcome (P < 0.05). hCGβ-overexpressing cell lines had increased invasiveness, migratory ability, and metastatic potential in mice (P < 0.01). Western blot, PCR, and microarray analyses showed hCGβ altered expression of EMT-related genes, including E-cadherin, phosphorylated SMAD2, SNAIL, and TWIST. hCGβ-induced SNAIL and TWIST overexpression levels were reversible by type I and type II TGF-β receptor inhibitors (P < 0.05). hCGβ thus induces EMT via the TGF-β signaling pathway, and it may represent a molecular target in CRC treatment.

Prognostic value of transforming growth factor-beta in patients with colorectal cancer who undergo surgery: a meta-analysis

Background

Transforming growth factor-beta (TGF-β) is associated with a higher incidence of distant metastasis and decreased survival. Whether TGF-β can be used as a prognostic indicator of colorectal cancer (CRC) remains controversial.

Methods

The Medline, EMBASE and Cochrane databases were searched from their inception to March 2016. The studies that focused on TGF-β as a prognostic factor in patients with CRC were included in this analysis. Overall survival (OS) and disease-free survival (DFS) were analysed separately. A meta-analysis was performed, and hazard ratios (HR) with 95% confidence intervals (CI) were calculated.

Results

Twelve studies were included in the analysis, of which 8 were used for OS and 7 for DFS. In all, 1622 patients with CRC undergoing surgery were included. Combined HRs suggested that high expression of TGF-β had a favourable impact on OS (HR = 1.68, 95% CI: 1.10–2.59) and DFS (HR = 1.11, 95% CI: 1.03–1.19) in CRC patients. For OS, the combined HRs of Asian studies and Western studies were 1.50 (95% CI: 0.61–3.68) and 1.80 (95% CI: 1.33–2.45), respectively. For DFS, the combined HRs of Asian studies and Western studies were 1.42 (95% CI: 0.61–3.31) and 1.11 (95% CI: 1.03–1.20), respectively.

Conclusions

This meta-analysis demonstrates that TGF-β can be used as a prognostic biomarker for CRC patients undergoing surgery, especially for CRC patients from Western countries.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3215-7) contains supplementary material, which is available to authorized users.

The distribution and potential prognostic value of SMAD protein expression in chronic lymphocytic leukemia

The SMAD proteins are responsible for transducing signals from activated transforming growth factor-beta. This is the first study assessing the expression of SMAD-1/8, SMAD-2/3, SMAD-4, and SMAD-7 in chronic lymphocytic leukemia cells with regard to their clinical significance and potential prognostic value. Overexpression of SMAD-1/8 was observed in 160 chronic lymphocytic leukemia patients compared to 42 healthy volunteers (p = 0.023) and was associated with a more progressive course of the disease (p = 0.016). Moreover, the high expression of SMAD-1/8 correlated with other, well-established prognostic factors, including clinical stage (p = 0.010) and lymphocyte doubling time (p = 0.021). The expression of SMAD-4 was lower in chronic lymphocytic leukemia patients compared with the control group (p = 0.003). Importantly, lower SMAD-4 levels correlated with longer progression-free survival (p = 0.009), progressive course of the disease (p = 0.002), advanced clinical stage (p = 0.0004), elevated beta-2-microglobulin and lactate dehydrogenase levels (p < 0.05), shorter lymphocyte doubling time (p = 0.009), and CD38 antigen expression (p = 0.039). In addition, lower SMAD-4 expression correlated with lower apoptotic index (p = 0.0007) and lower expression of receptors for vascular endothelial growth factors VEGFR-1 and VEGFR-2. A significant association was found between the low expression of inhibitory protein SMAD-7 and both zeta-chain-associated protein kinase 70–negative cells (p = 0.04) and lower apoptotic index (p = 0.004). No differences were observed in SMAD-2/3 expression. In conclusion, our results demonstrate a significant correlation between greater SMAD-1/8 and lower SMAD-4 expression in chronic lymphocytic leukemia cells, as well as more progressive outcome and poor prognosis. These data provide supporting evidence that the expression of SMAD proteins plays an important role in disease development and may be considered as a novel, biologic prognostic factor in this disease.

Chinese 1 strain of Toxoplasma gondii excreted-secreted antigens negatively modulate Foxp3 via inhibition of the TGFßRII/Smad2/Smad3/Smad4 pathway

Toxoplasma gondii is an opportunistic intracellular parasite and is considered an important aetiological factor in the process of abortion, especially as occurs in early gestation. Chinese 1 strain of T. gondii is a dominant genotype prevalent in China. Although it is known that early foetal resorption triggered by RH strain of T. gondii is attributable to immune mechanisms rather than its direct effect in uterus, the underlying mechanism of the abortion caused by Chinese 1 strain remains unclear. This study was designed to investigate the effect of excreted–secreted antigens (ESA) of Chinese 1 strain of T. gondii on the expression of forkhead box transcription factor (Foxp3) as it pertains to early pregnancy and abortion. ESA caused a marked inhibition in the expression of Foxp3 both in vivo and in vitro. In addition, ESA negatively modulated Smad2 and Smad3 at the posttranslational level. Smad2 siRNA cooperated with ESA to further suppress the level of Foxp3. This inhibitory effect on Foxp3 expression was partially abrogated by overexpression of Smad2, Smad3 and Smad4. Additionally, ESA attenuated the expression of TGFßRII, whereas TGFßRII agonist could profoundly reversed the decreased Foxp3 triggered by ESA. Collectively, the findings suggested that ESA restricted Foxp3 expression by inhibiting TGFßRII/Smad2/Smad3/Smad4 signalling, ultimately resulting in abortion.

The miR-487b-3p/GRM3/TGFβ signaling axis is an important regulator of colon cancer tumorigenesis

Molecular targeting is an import strategy to treat advanced colon cancer. The current study demonstrates that expression of GRM3, a metabotropic glutamate receptor mainly expressed in mammalian central nervous system, is significantly upregulated in majority of human colonic adenocarcinomas tested and colon cancer cell lines. Knockdown of GRM3 expression or inhibition of GRM3 activation in colon cancer cells reduces cell survival and anchorage-independent growth in vitro and inhibits tumor growth in vivo. Mechanistically, GRM3 antagonizes TGFβ-mediated activation of protein kinase A and inhibition of AKT. In addition, TGFβ signaling increases GRM3 protein stability and knockdown of GRM3 enhances TGFβ-mediated tumor suppressor function. Further studies indicate that miR-487b-3p directly targets GRM3. Overexpression of miR-487b-3p mimics the effects of GRM3 knockdown and suppresses the tumorigenicity of colon cancer cells in vivo. Expression of miR-487b-3p is decreased in colon adenocarcinomas and inversely correlates with GRM3 expression. Taken together, these studies indicate that upregulation of GRM3 expression is a functionally important molecular event in colon cancer, and that GRM3 is a promising molecular target for colon cancer treatment. This is particularly interesting and important from a therapeutic standpoint because numerous metabotropic glutamate receptor antagonists are available, many of which have been found unsuitable for treatment of neuropsychiatric disorders for reasons such as inability to readily penetrate blood brain barriers. Since GRM3 is upregulated in colon cancer, but rarely expressed in normal peripheral tissues, targeting GRM3 with such agents would not likely cause adverse neurological or peripheral side effects, making GRM3 an attractive and specific molecular target for colon cancer treatment.

Expression of VEGF-D, SMAD4, and SMAD7 and Their Relationship with Lymphangiogenesis and Prognosis in Colon Cancer

AIM

The vascular endothelial growth factor (VEGF) and TGF-β1 pathways play important roles in cancer. However, few studies have evaluated the expression and roles of VEGF-D, SMAD4, and SMAD7 in colon cancer, and the conclusions remain controversial. To clarify the roles of VEGF-D, SMAD4, and SMAD7 in colon cancer, we examined their expression and evaluated correlations with lymphangiogenesis, prognosis, and chemotherapeutic outcome.

METHODS

The expression of VEGF-D, SMAD4, and SMAD7 was immunohistochemically examined in 251 primary colon cancer samples obtained from the Harbin Medical University.

RESULTS

The expression of VEGF-D, SMAD4, and SMAD7 was identified in 71.7, 41.0, and 69.7 % of samples, respectively. Positive expression of VEGF-D and SMAD7 and lost expression of SMAD4 were significantly correlated with lymph node metastasis and high lymphatic vessel density. VEGF-D and SMAD7 were found to be independent indicators of prognosis and chemotherapy outcome, and positive expression of either VEGF-D or SMAD7 was associated with significantly shorter overall survival and disease-free survival (OS and DFS) than negative expression in all 251 patients (P < 0.001 for OS and DFS) and patients following chemotherapy (P < 0.001 for OS and DFS).

CONCLUSION

VEGF-D, SMAD4, and SMAD7 were involved in lymphangiogenesis and lymph node metastasis. VEGF-D and SMAD7 can serve as predictors of prognosis and chemotherapeutic outcome in colon cancer.

Are SMAD7 rs4939827 and CHI3L1 rs4950928 polymorphisms associated with colorectal cancer in Egyptian patients?

A wide variety of genes have been associated with colorectal cancer (CRC) development and progression. The SMAD7 gene encodes an intracellular protein, which inhibits the transforming growth factor beta (TGF-β) signaling pathway, thereby having a key role in the control of neoplastic processes in various organs. The CHI3L1 gene encodes glycoprotein YKL-40, which plays a role in cell proliferation, anti-apoptosis, and angiogenesis. The present study aimed to evaluate the association of single nucleotide polymorphisms (SNPs) SMAD7 rs4939827 and CHI3L1 rs4950928, as well as circulating TGFβ-1 and YKL-40 levels with CRC in an Egyptian population of 77 CRC patients and 36 healthy controls. Polymorphisms in the SMAD7 rs4939827 and the CHI3L1 rs4950928 genes were determined using the real-time polymerase chain reaction (RT-PCR). Both the SMAD7 rs4939827 TT genotype and the CHI3L1 rs4950928 C allele were associated with the rectal but not the colon cancer. In addition, the C allele of both SMAD7 rs4939827 and CHI3L1 rs4950928 was associated with increased serum levels of TGF-β1 and YKL-40, respectively. In conclusion, our data suggest that SMAD7 rs4939827 and CHI3L1 rs4950928 SNPs have no significant association with CRC. A significant association of SNP in SMAD7 rs4939827 and CHI3L1 rs4950928 was revealed between the rectal cancer and colon cancer patients.

Changes of immunocytic phenotypes and functions from human colorectal adenomatous stage to cancerous stage: Update

It is believed that chronic inflammation as seen in patients with ulcerative colitis significantly increases the colorectal cancer (CRC) risk and functions as the main driving force for the development of colitis associated CRC. Recently, increasing evidences suggest that inflammation is also involved in the processing of sporadic CRCs that mostly develop from the preformed adenomas through a long-term progression. Within the adenoma/CRC tumor microenvironment, high dense immunocytes with significant phenotypic and functional changes have been observed. These cells might produce high level of inflammatory mediators and then affect the adenoma-cancer transition. In this review, we summarize the update on altered phenotypes and inflammatory mediators within the tumor microenvironment from the adenomatous stage to the cancerous stage, and discuss the significance of inflammatory mediators as biomarkers in predicating the progression from the premalignant adenoma lesion to the sporadic CRC lesion and the potential as therapeutic targets.

A Meta-Analysis of SMAD4 Immunohistochemistry as a Prognostic Marker in Colorectal Cancer

AIM: SMAD4 immunohistochemistry is considered a valuable prognostic marker in colorectal cancer, but individual studies have often been small and the results variable. A meta-analysis could potentially clarify these findings. METHODS: In September 2014, a Pubmed and Google Scholar search was conducted to find publications that reported the prognostic value of SMAD4 expression. A meta-analysis was performed to clarify the association between SMAD4 expression and survival outcomes. RESULTS: 137 studies were found, of which 13 were considered eligible. The studies consisted of a total of 3800 patients. Three different endpoints were taken into account, namely, overall survival (OS), disease-free survival (DFS), and cancer-specific survival (CSS). In addition, the studies were divided into univariate and multivariate analyses. The pooled hazard ratios were given as follows: univariate CSS = 1.75 [95% confidence interval (CI): 0.93-3.32; z= 1.69; P= .09]; multivariate CSS = 2.17 (95% CI: 1.56-3.01; z= 4.65; P= .000); univariate DFS = 2.11 (95% CI: 1.36-3.28; z= 3.32; P= .001); multivariate DFS = 2.15 (95% CI: 1.56-3.01; z= 4.65; P= .000); univariate OS and DFS = 2.30 (95% CI: 1.41-3.73; z= 3.36; P= .001); univariate OS = 2.28 (95% CI: 1.30-4.00; z= 2.89; P= .004). CONCLUSION: The results of the presented meta-analyses indicate that SMAD4 expression status using immunohistochemistry is a prognostic marker for patient survival.

Multiple functional risk variants in a SMAD7 enhancer implicate a colorectal cancer risk haplotype

Genome-wide association studies (GWAS) of colorectal cancer (CRC) have led to the identification of a number of common variants associated with modest risk. Several risk variants map within the vicinity of TGFβ/BMP signaling pathway genes, including rs4939827 within an intron of SMAD7 at 18q21.1. A previous study implicated a novel SNP (novel 1 or rs58920878) as a functional variant within an enhancer element in SMAD7 intron 4. In this study, we show that four SNPs including novel 1 (rs6507874, rs6507875, rs8085824, and rs58920878) in linkage disequilibrium (LD) with the index SNP rs4939827 demonstrate allele-specific enhancer effects in a large, multi-component enhancer of SMAD7. All four SNPs demonstrate allele-specific protein binding to nuclear extracts of CRC cell lines. Furthermore, some of the risk-associated alleles correlate with increased expression of SMAD7 in normal colon tissues. Finally, we show that the enhancer is responsive to BMP4 stimulation. Taken together, we propose that the associated CRC risk at 18q21.1 is due to four functional variants that regulate SMAD7 expression and potentially perturb a BMP negative feedback loop in TGFβ/BMP signaling pathways.

Molecular mechanism of TGF-β signaling pathway in colon carcinogenesis and status of curcumin as chemopreventive strategy

Colon cancer is one of the third most common cancer in man, the second most common cancer in women worldwide, and the second leading cause of mortality in the USA. There are a number of molecular pathways that have been implicated in colon carcinogenesis, including TGF-β/Smad signaling pathway. TGF-β (transforming growth factor-beta) signaling pathway has the potential to regulate various biological processes including cell growth, differentiation, apoptosis, extracellular matrix modeling, and immune response. TGF-β signaling pathway acts as a tumor suppressor, but alterations in TGF-β signaling pathway promotes colon cancer cell growth, migration, invasion, angiogenesis, and metastasis. Here we review the role of TGF-β signaling cascade in colon carcinogenesis and multiple molecular targets of curcumin in colon carcinogenesis. Elucidation of the molecular mechanism of curcumin on TGF-β signaling pathway-induced colon carcinogenesis may ultimately lead to novel and more effective treatments for colon cancer.

Low expression of transforming growth factor beta-1 in cancer tissue predicts a poor prognosis for patients with stage III rectal cancers

OBJECTIVE

Transforming growth factor beta (TGF-β) plays an important role in tumorigenesis and metastasis. It works as a tumor suppressor in the normal colon, but acts as a cancer promoter during the late stages of colorectal carcinogenesis. High expression of TGF-β is known to be associated with advanced stages, tumor recurrence and decreased survival of patients. We investigated the expression of TGF-β and its signaling axis molecules and evaluated their prognostic significance in patients with stage III rectal cancers.

METHODS

Tissues from 201 cases of stage III rectal cancer were subjected to immunohistochemistry for TGF-β1, type II TGF-β receptor, Smad3, Smad4 and Smad7 proteins. The immunoactivities of these molecules were evaluated and the results were compared with clinicopathological variables including patient survival.

RESULTS

Low expression of TGF-β1 protein was correlated with a decreased disease-free survival in univariate Kaplan-Meier (p = 0.003) and multivariate Cox regression (HR 9.188 and 95% CI 1.256-67.198, p = 0.029) analyses. The loss of Smad4 protein expression was associated with a reduction in disease-free survival in the univariate analysis, but this finding was not significant after the multivariate analysis.

CONCLUSION

Low expression of TGF-β1 protein is associated with a poor prognosis for patients with stage III rectal cancers.

Identification of the angiogenic gene signature induced by EGF and hypoxia in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is characterised by hypoxia, which activates gene transcription through hypoxia-inducible factors (HIF), as well as by expression of epidermal growth factor (EGF) and EGF receptors, targeting of which has been demonstrated to provide therapeutic benefit in CRC. Although EGF has been demonstrated to induce expression of angiogenic mediators, potential interactions in CRC between EGF-mediated signalling and the hypoxia/HIF pathway remain uncharacterised.

METHODS

PCR-based profiling was applied to identify angiogenic genes in Caco-2 CRC cells regulated by hypoxia, the hypoxia mimetic dimethyloxallylglycine (DMOG) and/or EGF. Western blotting was used to determine the role of HIF-1alpha, HIF-2alpha and MAPK cell signalling in mediating the angiogenic responses.

RESULTS

We identified a total of 9 angiogenic genes, including angiopoietin-like (ANGPTL) 4, ephrin (EFNA) 3, transforming growth factor (TGF) β1 and vascular endothelial growth factor (VEGF), to be upregulated in a HIF dependent manner in Caco-2 CRC cells in response to both hypoxia and the hypoxia mimetic dimethyloxallylglycine (DMOG). Stimulation with EGF resulted in EGFR tyrosine autophosphorylation, activation of p42/p44 MAP kinases and stabilisation of HIF-1α and HIF-2α proteins. However, expression of 84 angiogenic genes remained unchanged in response to EGF alone. Crucially, addition of DMOG in combination with EGF significantly increased expression of a further 11 genes (in addition to the 9 genes upregulated in response to either DMOG alone or hypoxia alone). These additional genes included chemokines (CCL-11/eotaxin-1 and interleukin-8), collagen type IV α3 chain, integrin β3 chain, TGFα and VEGF receptor KDR.

CONCLUSION

These findings suggest that although EGFR phosphorylation activates the MAP kinase signalling and promotes HIF stabilisation in CRC, this alone is not sufficient to induce angiogenic gene expression. In contrast, HIF activation downstream of hypoxia/DMOG drives expression of genes such as ANGPTL4, EFNA3, TGFβ1 and VEGF. Finally, HIF activation synergises with EGF-mediated signalling to additionally induce a unique sub-group of candidate angiogenic genes. Our data highlight the complex interrelationship between tumour hypoxia, EGF and angiogenesis in the pathogenesis of CRC.

Relationship of TGF-β1 and Smad7 expression with decreased dendritic cell infiltration in liver gastrointestinal cancer metastasis

Immune responses and their modulation within the liver are critical to the outcome of liver malignancies. In late-stage tumors, secreted TGF-β promotes oncogenic functions and can confer tolerogenicity to some immune cells like DCs. The TGF-β signaling pathway is involved in the control of several biological processes, including immunosurveillance. The aim of the present study was to assess CD1a(+) and CD83(+) DCs and to evaluate the impact of TGF-β pathway on DCs maturation and distribution in the liver metastases from gastric and colorectal tumors. The percentage of CD83(+) DCs in the liver tissue, surrounding metastasis and in the metastasis-free liver was measured by flow cytometry, and TGF-β levels were assessed in the tissue supernatant from the peritumoral liver after mononuclear cell isolation and in the sera of the same patients. CD1a(+) and CD83(+) DCs were observed in the tumor stroma and border. Out of 73 patients, there was cytoplasmic reactivity: of TGF-β1 in 37 (50.7%); of Smad4 in 62 (84.9%); of Smad7 in 46 (63%), and of TGFβRII in 39 (53.4%) of the metastases. The TGF-β1 expression in tumor cell cytoplasm correlated with low CD1a(+) and low CD83(+) DCs infiltration. The tissue levels of TGF-β1, measured by ELISA in the supernatant were significantly increased in metastases than in normal liver. Using a two-color FACS analysis, we found that the percentage of HLA-DR(+) CD83(+) DCs in metastases was significantly decreased as compared with metastasis-free liver tissue. In conclusion, the positive and negative correlations between the mediators from the TGF-β pathway implied the existence of imbalance and suppression of this cytokine activity. The presence of increased TGF-β expression by immunohistochemistry in tumor cells was confirmed by detection of increased TGF-β tissue level in the supernatant from the tissue homogenate. The observation of low numbers of CD1a(+) and CD83(+) DCs in tumor stroma correlated with TGF-β overexpression in tumor cells, a fact that well documents the immunosuppressive role of TGF-β in metastasis development. The increased percentage of CD83(+) DCs in the peritumoral tissue supposes that there could be active recruitment or local differentiation of DCs in the metastasis border, but inside the tumor the immune cells recruitment and activity are suppressed by TGF-β and by other cytokines.

The density of macrophages in colorectal cancer is inversely correlated to TGF-β1 expression and patients' survival

The role of macrophages in colorectal cancer tumorogenesis is complex because they can both prevent and promote tumor development. We investigated CD68-positive cell infiltration in tumor tissue and its correlations with proteins of TGF-β1 signaling pathway and survival of the patients after surgical therapy. A non-selected panel of 210 primary tumors of colorectal origin was investigated immunohistochemically with antibodies against CD68, TGF-β1, TGFβRII and Smad4. Lower CD68 infiltration in tumor stroma was associated with expression of TGF-β1 (p = 0.002) and SMAD4 (p = 0.090) in tumor cell cytoplasm and with TGFβRII expression (p = 0.017) in tumor cells membranes. The absence of SMAD4 immune deposits in tumor cell nuclei was more often seen in biopsies with low number of CD68 in the invasive front (p = 0.044). The low number of CD68-positive cells was significantly associated with several adverse clinical and histological tumor characteristics as the presence of metastases in local lymph nodes (p = 0.047), distant metastases (p = 0.0003), advanced tumor stage (p = 0.006), tumor cell invasion of blood, lymph vessels or perineural invasion (p = 0.004), higher histological types (p = 0.0002) and lower grade of inflammatory infiltration in the invasive front (p = 0.002). Moreover, the low grade of CD68 appeared to be significant unfavorable factors of prognosis of the patients with colorectal cancer. The results of our study confirm the prognostic significance of low level of tumor-associated macrophage infiltration in colorectal cancer as unfavorable marker for survival of the patients.

Quantitative analysis of cancer-associated gene methylation connected to risk factors in Korean colorectal cancer patients

Objectives

The purpose of this paper was to elucidate the potential methylation levels of adjacent normal and cancer tissues by comparing them with normal colorectal tissues, and to describe the correlations between the methylation and clinical parameters in Korean colorectal cancer (CRC) patients.

Methods

Hypermethylation profiles of nine genes (RASSF1, APC, p16^INK4a, Twist1, E-cadherin, TIMP3, Smad4, COX2, and ABCB1) were examined with 100 sets of cancer tissues and 14 normal colorectal tissues. We determined the hypermethylation at a given level by a percent of methylation ratio value of 10 using quantitative methylation real-time polymerase chain reaction.

Results

Nine genes' hypermethylation levels in Korean CRC patient tissues were increased more higher than normal colorectal tissues. However, the amounts of p16^INK4a and E-cadherin gene hypermethylation in normal and CRC tissues were not significantly different nor did TIMP3 gene hypermethylation in adjacent normal and cancer tissues differ significantly. The hypermethylation of TIMP3, E-cadherin, ABCB1, and COX2 genes among other genes were abundantly found in normal colorectal tissues. The hypermethylation of nine genes' methylation in cancer tissues was not significantly associated with any clinical parameters. In Cohen's kappa test, it was moderately observed that RASSF1 was related with E-cadherin, and Smad4 with ABCB1 and COX2.

Conclusions

This study provides evidence for different hypermethylation patterns of cancer-associated genes in normal and CRC tissues, which may serve as useful information on CRC cancer progression.

Expression of TGF-β1 and Smad2 in human gastric cancer

AIM: To investigate the correlation of the expression of transforming growth factor-β1 (TGF-β1) and mothers against decapentaplegic homolog 2 (Smad2) with the carcinogenesis and tumor progression of human gastric cancer.

METHODS: Western blot and real-time PCR were used to detect the expression of TGF-β1 and Smad2 protein and mRNA in 45 cases of gastric cancer and matched normal gastric mucosal tissues.

RESULTS: The positive rates of TGF-β1 and Smad2 protein expression were significantly higher in gastric cancer than in normal gastric mucosa (77.8% vs 33.3%, 73.3% vs 26.7%, both P < 0.05). The positive rates of TGF-β1 and Smad2 mRNA expression were also significantly higher in gastric cancer than in normal tissue (88.9% vs 35.6%, 84.4% vs 31.1%, both P < 0.05). The protein expression of TGF-β1 and Smad2 was correlated with pathological grade, lesion depth, lymph node metastasis and vessel invasion.

CONCLUSION: Overexpression of TGF-β1 and Smad2 may play an important role in the development and progression of gastric cancer.

Immune microenvironmental shift along human colorectal adenoma-carcinoma sequence: is it relevant to tumor development, biomarkers and biotherapeutic targets?

Human colorectal carcinoma (CRC) is one of the leading cancers. Every year, the WHO estimates a total of 945,000 new CRC cases, with 492,000 deaths worldwide. Most CRCs arise from the main premalignant lesion, colorectal adenomas, and the progression of colorectal adenoma to CRCs may take a long-term time course. The development of human CRCs is not only determined by the adenomatous cells, but also by the interaction between adenomatous cells and host immune environment. In response to tumor initiation or invasion, many inflammatory cells and components will be inevitably activated and form an inflammatory microenvironment surrounding the CRC tumors. Accumulative evidence has revealed that inflammatory response plays a key role in the development of human CRCs by implicating in many aspects including in determining the microenvironmental immune function shift from immunosurveillance to immunosuppression and significantly influences the progression of precancerous lesions to cancers. In this review, the functional changes of immune microenvironment from precancerous stage (adenoma) to cancer stage are summarized, and their potential as predictive biomarkers and biotherapeutic significance in preventing the development of CRCs are discussed.

Prognostic role of CD10⁺ myeloid cells in association with tumor budding at the invasion front of colorectal cancer

The expression of CD10 in tumor cells has been reported to correlate with liver metastasis in colorectal cancer (CRC). However, fibroblasts and immune cells positive for CD10 at the tumor invasion front have not been comprehensively studied. We classified CD10 expression patterns into three types of cells, tumor cells (tCD10), stromal myofibroblasts (sCD10), and immune cells (iCD10), and investigated their correlation with the expression of transforming growth factor-β (TGF-β1) protein and tumor budding grade. Several cell surface markers were stained to detect the phenotype of iCD10(+) cells, including CD3, CD20, CD11b, CD14, CD15, and CD163. Specimens and follow-up data of 206 CRC patients were examined. In multivariate analysis, iCD10 could be an independent prognostic factor for both recurrence-free survival and overall survival in stage I-III CRC (hazard ratio, 2.522 [1.299-4.896], P = 0.006; 2.890 [1.357-6.157], P = 0.006, respectively). The expression of sCD10 and iCD10 was strongly correlated with TGF-β1 expression in tumor cells and tumor budding grade. The phenotype of iCD10(+) cells was CD11b(+) and CD15(+) granulocytes. The infiltration of sCD10(+) fibroblasts and iCD10(+) granulocytes at the tumor invasion front might interact with TGF-β1 protein expression and enhance tumor budding grade. The expression level of iCD10 at the tumor invasion front represented an independent prognostic biomarker in stage I-III CRC and could be integrated into a new staging system.

Association between TGFBR2 gene polymorphism (rs2228048, Asn389Asn) and intracerebral hemorrhage in Korean population

Transforming growth factor, beta receptor II (TGFBR2) is mainly expressed by neurons in the central nervous system, and reduced neuronal TGFBR2 signaling results in accelerated age-dependent neurodegeneration. To investigate whether TGFBR2 polymorphisms are associated with ischemic stroke (IS) and intracerebral hemorrhage (ICH), two single nucleotide polymorphisms (SNPs) of TGFBR2 gene (rs764522, -1444C/G; rs2228048, Asn389Asn) were selected and genotyped by direct sequencing in 247 stroke patients (120 IS and 127 ICH) and 655 control subjects (260 for IS and 395 for ICH). SNPStats, SNPAnalyzer, Helixtree, and Haploview version 4.2 were used to analyze genetic data. Multiple logistic regression models (codominant, dominant, recessive, and log-additive) were performed to evaluate odds ratios (ORs), 95% confidence intervals (CIs), and p values. The synonymous SNP rs2228048 was significantly associated with ICH (p = 0.032 in codominant 2 model, p = 0.024 in dominant model, p = 0.020 in recessive model, and p = 0.005 in log-additive model) and Fisher's exact test (p = 0.009). Allele frequencies of rs2228048 were different between ICH and controls (p = 0.006). In Bonferroni correction, these correlations were also significant. These results suggest that the synonymous SNP rs2228048 of TGFBR2 gene may be associated with development of ICH in Korean population.

Genetic variation in the transforming growth factor-β signaling pathway and survival after diagnosis with colon and rectal cancer

BACKGROUND

The transforming growth factor-β (TGF-β) signaling pathway is involved in many aspects of tumorigenesis, including angiogenesis and metastasis. The authors evaluated this pathway in association with survival after a diagnosis of colon or rectal cancer.

METHODS

The study included 1553 patients with colon cancer and 754 patients with rectal cancer who had incident first primary disease and were followed for a minimum of 7 years after diagnosis. Genetic variations were evaluated in the genes TGF-β1 (2 single nucleotide polymorphisms [SNPs]), TGF-β receptor 1 (TGF-βR1) (3 SNPs), smooth muscle actin/mothers against decapentaplegic homolog 1 (Smad1) (5 SNPs), Smad2 (4 SNPs), Smad3 (37 SNPs), Smad4 (2 SNPs), Smad7 (11 SNPs), bone morphogenetic protein 1 (BMP1) (11 SNPs), BMP2 (5 SNPs), BMP4 (3 SNPs), bone morphogenetic protein receptor 1A (BMPR1A) (9 SNPs), BMPR1B (21 SNPs), BMPR2 (11 SNPs), growth differentiation factor 10 (GDF10) (7 SNPs), Runt-related transcription factor 1 (RUNX1) (40 SNPs), RUNX2 (19 SNPs), RUNX3 (9 SNPs), eukaryotic translation initiation factor 4E (eiF4E) (3 SNPs), eukaryotic translation initiation factor 4E-binding protein 3 (eiF4EBP2) (2 SNPs), eiF4EBP3 (2 SNPs), and mitogen-activated protein kinase 1 (MAPK1) (6 SNPs).

RESULTS

After adjusting for American Joint Committee on Cancer stage and tumor molecular phenotype, 12 genes and 18 SNPs were associated with survival in patients with colon cancer, and 7 genes and 15 tagSNPs were associated with survival after a diagnosis of rectal cancer. A summary score based on "at-risk" genotypes revealed a hazard rate ratio of 5.10 (95% confidence interval, 2.56-10.15) for the group with the greatest number of "at-risk" genotypes; for rectal cancer, the hazard rate ratio was 6.03 (95% confidence interval, 2.83-12.75).

CONCLUSIONS

The current findings suggest that the presence of several higher risk alleles in the TGF-β signaling pathway increase the likelihood of dying after a diagnosis of colon or rectal cancer.

Genetics, cytogenetics, and epigenetics of colorectal cancer

Most of the colorectal cancer (CRC) cases are sporadic, only 25% of the patients have a family history of the disease, and major genes causing syndromes predisposing to CRC only account for 5-6% of the total cases. The following subtypes can be recognized: MIN (microsatellite instability), CIN (chromosomal instability), and CIMP (CpG island methylator phenotype). CIN occurs in 80-85% of CRC. Chromosomal instability proceeds through two major mechanisms, missegregation that results in aneuploidy through the gain or loss of whole chromosomes, and unbalanced structural rearrangements that lead to the loss and/or gain of chromosomal regions. The loss of heterozygosity that occur in the first phases of the CRC cancerogenesis (in particular for the genes on 18q) as well as the alteration of methylation pattern of multiple key genes can drive the development of colorectal cancer by facilitating the acquisition of multiple tumor-associated mutations and the instability phenotype.

CD1a and CD1d genes polymorphisms in breast, colorectal and lung cancers

CD1 molecules might contribute to anti-tumor immune response by presentation of tumor-derived lipid and glycolipid antigens to T cells and NKT cells. Polymorphisms in CD1 genes have been suggested to modify ligand binding of CD1 molecules and thereby change the antigen presenting ability of these molecules. The aim of this study was to investigate the exon 2 polymorphisms of CD1a and CD1d in several high incident cancers in Iran. For this purpose, 201 female breast cancer patients and 207 healthy women, 64 lung cancer patients and 95 healthy individuals and 109 patients with colorectal cancer and 109 healthy controls were recruited to this study. Using PCR-SSP method, no significant correlation was found in genotype and allele frequencies of CD1a between all three studied groups and their control counterparts. Moreover, a dominant frequency of CD1d 01 (A) allele was observed in the majority of studied individuals. No significant association between the CD1 polymorphisms and prognostic factors in breast, lung and colorectal cancers was detected. Our results highlight the conserved nature of CD1 genes and may point to the immuoregulatory functions of CD1 molecules in cancer that can be exerted through fine tuning of NK, T and NKT cells.

Variable selection for discriminant analysis with Markov random field priors for the analysis of microarray data

MOTIVATION

Discriminant analysis is an effective tool for the classification of experimental units into groups. Here, we consider the typical problem of classifying subjects according to phenotypes via gene expression data and propose a method that incorporates variable selection into the inferential procedure, for the identification of the important biomarkers. To achieve this goal, we build upon a conjugate normal discriminant model, both linear and quadratic, and include a stochastic search variable selection procedure via an MCMC algorithm. Furthermore, we incorporate into the model prior information on the relationships among the genes as described by a gene-gene network. We use a Markov random field (MRF) prior to map the network connections among genes. Our prior model assumes that neighboring genes in the network are more likely to have a joint effect on the relevant biological processes.

RESULTS

We use simulated data to assess performances of our method. In particular, we compare the MRF prior to a situation where independent Bernoulli priors are chosen for the individual predictors. We also illustrate the method on benchmark datasets for gene expression. Our simulation studies show that employing the MRF prior improves on selection accuracy. In real data applications, in addition to identifying markers and improving prediction accuracy, we show how the integration of existing biological knowledge into the prior model results in an increased ability to identify genes with strong discriminatory power and also aids the interpretation of the results.

FMNL2 enhances invasion of colorectal carcinoma by inducing epithelial-mesenchymal transition

FMNL2 is a member of diaphanous-related formins that control actin-dependent processes such as cell motility and invasion. Its overexpression in metastatic cell lines and tissues of colorectal carcinoma has been associated with aggressive tumor development in our previous study. But its specific role in cancer is largely unknown. Here we report that FMNL2 is involved in epithelial-mesenchymal transition (EMT) maintenance in human colorectal carcinoma cells. A positive correlation between FMNL2 and vimentin expression and an inverse correlation between FMNL2 and E-cadherin expression were found in colorectal carcinoma cell lines and cancer tissues. Specific knockdown of FMNL2 led to an epithelial-state transition, confirmed by the cobblestone-like phenotype, upregulation of E-cadherin, α-catenin, and γ-catenin, and downregulation of vimentin, snail, slug. Loss of FMNL2 expression lowered the ability of TGF-β to induce cell invasion and EMT, as shown by morphology and the expression levels. Upregulation of vimentin, slug, snail, downregulation of E-cadherin and activation of receptor-Smad3 phosphorylation were observed in M5 and MDCK cells induced by TGF-β, whereas altered expression of these markers was not obvious in FMNL2-depleting M5 cells. High levels of activation of p-MAPK and p-MEK, but not p-PI3K and p-AKT, were observed in SW480/FMNL2+ cells compared with control cells. Treatment with U0126 could abrogate the activation of p-MAPK and p-MEK, whereas LY294002 treatment had no effect on the PI3K/AKT pathway. In conclusion, these findings identify a novel EMT and tumor promoting function for FMNL2, which is involved in TGF-β-induced EMT and colorectal carcinoma cell invasion via Smad3 effectors, or in collaboration with MAPK/MEK pathway.