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

RUNX3 mediates keloid fibroblast proliferation through deacetylation of EZH2 by SIRT1

BACKGROUND

Keloid is a benign proliferative fibrous disease featured by excessive fibroblast proliferation after skin injury. However, the mechanism of abnormal cell proliferation is still unclear. Herein, we investigated the mechanism of abnormal proliferation in keloids involving Sirtuin 1(SIRT1)/ Zeste Homolog 2 (EZH2)/ Runt-related transcription factor 3 (RUNX3).  METHODS: HE staining was used to observe the histopathological changes. Western blot was performed to detect SIRT1/EZH2/RUNX3 and cell cycle related proteins. RT-PCR detected EZH2 mRNA. After knockdown of EZH2 or overexpression of RUNX3, cell proliferation and cell cycle was analyzed. Immunoprecipitation was used to detect acetylated EZH2.

RESULTS

The results showed that overexpression of RUNX3 inhibited cell proliferation and arrested cell cycle at G1/S phase, whereas inhibition of SIRT1 promoted cell proliferation and G1/S phase of the cell cycle. Knockdown of EZH2 promoted the expression of RUNX3, inhibited cell proliferation and shortened the progression of G1 to S phase. Simultaneous knockdown of EZH2 and inhibition of SIRT1 reversed these effects. Inhibition of SIRT1 increased its protein stability by increasing EZH2 acetylation, thereby reducing the expression of RUNX3 and promoting cell proliferation.

CONCLUSIONS

Conclusively, the SIRT1/EZH2/RUNX3 axis may be an important pathway in the regulation of abnormal proliferation in keloids.

TRIM44 Promotes Endometrial Carcinoma Progression by Activating the FRS2 Signalling Pathway

The Tripartite Motif Containing 44 (TRIM44) is highly expressed in a variety of tumours. However, the TRIM44's role in endometrial carcinoma (EC) progression remains unknown. To investigate the TRIM44's role in the development and metastasis of EC, we detected TRIM44 expression in EC cell lines and surgical specimens from patients with EC using immunohistochemistry, real-time reverse transcription-polymerase chain reaction, and western blotting analysis. The biological functions of TRIM44 by loss-of-function analysis in RL95-2 and Ishikawa cells were studied. The effect of TRIM44 on the progression of EC in terms of cell proliferation, apoptosis, and invasion was examined and revealed its underlying mechanism in vitro using EC cell lines and in vivo using mouse xenograft models. The TRIM44's expression was positively correlated with EC progression and poor prognosis. The TRIM44 knockdown reduced the EC cell proliferation and invasion while promoting cell apoptosis. Mechanism experiments showed that the TRIM44 interacts with Fibroblast Growth Factor Receptor Substrate 2 (FRS2) and negatively regulates the expression of Bone Morphogenetic Protein 4(BMP4), β-catenin, and Transforming Growth Factor Beta Receptor 1(TGF-βR1). Moreover, the effect of TRIM44 overexpression on EC cell proliferation, invasion, and apoptosis is reversed by the FRS2 knockdown. Our study may provide a new perspective on targeting the TRIM44/FRS2 signaling pathway in treating EC, which deserves further investigation.

Effect of Hesperidin against Induced Colon Cancer in Rats: Impact of Smad4 and Activin A Signaling Pathway

SCOPE

To evaluate the chemopreventive efficacy of hesperidin (Hsd) in 1,2-dimethylhydrazine (DMH)-induced colorectal cancer (CRC) and demonstrate its role in mothers against decapentaplegic homolog 4(Smad4) and activin A signaling pathways.

METHODS AND RESULTS

A CRC rat model was established by DMH exposure, and the animals were randomly divided into five groups: Control group, Hsd, DMH, DMH + Hsd, and DMH followed by Hsd. The resected colon was subjected to macroscopic, microscopic, molecular, histopathological, and immunohistochemical examination. Activin A, Smad4, malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), and superoxide dismutase (SOD) levels in tissues were also measured. The DMH group exhibited a significant increase in the gene and protein expression of activin A as well as MDA and NO levels in tissues. There was a significant reduction in the gene and protein expression of Smad4 as well as GSH and SOD levels in tissues. Administration of Hsd significantly upregulated Smad4 and activin A gene expressions in both the DMH + Hsd and DMH followed by Hsd groups. Moreover, Hsd improved the antioxidant status of the former two groups.

CONCLUSION

This study demonstrated the chemopreventive effect of Hsd against CRC by modulating Smad4 and activin A signaling in vivo. Further studies are needed to demonstrate its clinical value and explore its possible role in advanced malignancy.

Role and clinical significance of TGF‑β1 and TGF‑βR1 in malignant tumors (Review)

The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-β (TGF-β) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-β signaling pathway, TGF-β1 and TGF-β receptor 1 (TGF-βR1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-β1 and TGF-βR1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-κB signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-β1 and TGF-βR1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-β1 or TGF-βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.

Variants of SMAD1 gene increase the risk of colorectal cancer in the Bangladeshi population

Colorectal cancer is the fourth most common type of malignancy worldwide that may develop due to the accumulation of several genetic variations. Different single nucleotide polymorphisms of SMAD1 gene are assumed to be linked with increased colorectal cancer risk. The current case-control study was conducted to verify the association of genetic polymorphisms of SMAD1 (rs11100883 and rs7661162) with colorectal cancer in the Bangladeshi population. This study was performed on 275 colorectal cancer patients and 300 healthy volunteers using polymerase chain reaction-restriction fragment length polymorphism method. The odds ratios were adjusted for age and sex with logistic regression analysis. In case of SMAD1 rs11100883 polymorphism, GA heterozygous genotype, GA + AA (dominant model), and minor allele "A" were significantly associated with colorectal cancer (adjusted odds ratio = 1.55, 95% confidence interval = 1.09-2.20, p = 0.014; adjusted odds ratio = 1.59, 95% confidence interval = 1.13-2.23, p = 0.008; and odds ratio = 1.35, 95% confidence interval = 1.06-1.73, p = 0.015, respectively) and the significance exists after the Bonferroni correction. Again, single nucleotide polymorphism rs7661162 showed significant association with an elevated colorectal cancer risk for AG heterozygous genotype, AG + GG (dominant model), AG versus AA + GG (overdominant model), and minor allele "G" (adjusted odds ratio = 1.78, 95% confidence interval = 1.24-2.56, p = 0.002; adjusted odds ratio = 1.68, 95% confidence interval = 1.18-2.39, p = 0.004; adjusted odds ratio = 1.76, 95% confidence interval = 1.23-2.53, p = 0.002; and odds ratio = 1.47, 95% confidence interval = 1.08-2.00, p = 0.014, respectively) and significance withstands after the Bonferroni correction. No significant age and gender differences between cases and controls were observed. In silico, gene expression analysis showed that the SMAD1 mRNA level was downregulated in the colon and rectal cancer tissues compared to healthy tissues. In conclusion, our findings indicate that SMAD1 rs11100883 and rs7661162 polymorphisms are responsible for increasing the susceptibility of colorectal cancer development in the Bangladeshi population.

SMADs binding site polymorphisms rs9911630 is associated with susceptibility but not prognosis of gastric cancer: a case control study

Background: Single nucleotide polymorphisms (SNPs) in transcription factor binding sites (TFBS) can change their binding strength, affecting the function of transcription factors (TFs). Small mother against decapentaplegic (SMAD) proteins are known as a family of TFs involved in tumorigenesis. We performed this study to investigate whether SNPs in SMADs binding sites affect the susceptibility or prognosis of gastric cancer (GC).

Methods: Using bioinformatics tools, we focused on the association between rs9911630 polymorphism and GC. We performed this case-control study in 1275 GC patients and 1426 cancer-free subjects using TaqMan allelic discrimination method.

Results: We found that rs9911630 A>G polymorphism was associate to an increased risk of gastric cancer (adjusted OR for additive model = 1.16; 95% CI = 1.03-1.30). Furthermore, we assess whether rs9911630 polymorphism affected the prognosis of GC. However, no significant association was discovered between rs9911630 A>G polymorphism and overall survival time of GC patients (HR for addictive model = 1.01; 95%CI = 0.88-1.15).

Conclusions: Our results suggested that rs9911630 polymorphism in SMADs target site might influence susceptibility but not prognosis of gastric cancer.

Optimal Bayesian Filtering for Biomarker Discovery: Performance and Robustness

Optimal Bayesian feature filtering (OBF) is a fast and memory-efficient algorithm that optimally identifies markers with distributional differences between treatment groups under Gaussian models. Here, we study the performance and robustness of OBF for biomarker discovery. Our contributions are twofold: (1) we examine how OBF performs on data that violates modeling assumptions, and (2) we provide guidelines on how to set input parameters for robust performance. Contribution (1) addresses an important, relevant, and commonplace problem in computational biology, where it is often impossible to validate an algorithm's core assumptions. To accomplish both tasks, we present a battery of simulations that implement OBF with different inputs and challenge each assumption made by OBF. In particular, we examine the robustness of OBF with respect to incorrect input parameters, false independence, imbalanced sample size, and we address the Gaussianity assumption by considering performance on an extensive family of non-Gaussian distributions. We address advantages and disadvantages between different priors and optimization criteria throughout. Finally, we evaluate the utility of OBF in biomarker discovery using acute myeloid leukemia (AML) and colon cancer microarray datasets, and show that OBF is successful at identifying well-known biomarkers for these diseases that rank low under moderated t-test.

Runx3 expression in rectal cancer cells and its effect on cell invasion and proliferation

Effect of Runx3 gene on the cell proliferation and invasion of rectal cancer was investigated to explore potential new targets for targeted treatment of rectal cancer. The Runx3 overexpression group (OE group), blank plasmid control group, negative control and blank group of the rectal cancer HRC-9698 cell strain were set. The overexpressed Runx3 plasmid was transfected in OE group; the empty plasmid was transfected in blank plasmid control group; only liposome Lipofectamine was added to negative control group; only 1640 medium was used in blank group. RT-qPCR was used for detection of the mRNA expression of Runx3 in different groups; CCK-8 kit for detection of cell proliferation in different groups; Transwell chamber test for detection of cell strain invasion in different groups. The mRNA expression of Runx3 gene in OE group was the highest, significantly higher than that in blank plasmid control group, negative control and blank group (P<0.01). The OD values of overexpressed Runx3 at 96 h after transfection in OE group was significantly lower than each control group (P<0.01). At the same time-point, pairwise comparison in each group found that OE group was significantly lower than blank plasmid control, negative control and blank groups (all P<0.01). In the invasion experiment, the number of invasion cells in OE, blank plasmid control, negative control and blank groups were 38.63±9.33, 107.87±5.66, 110.93±4.33 and 112.86±6.66, respectively. OE group was significantly lower than each control group (P<0.01). Overexpression of Runx3 gene in vitro inhibits the cell proliferation of rectal cancer and blocks the cell invasion and metastasis. This study provides a new idea and a new molecular therapeutic target for molecular targeted therapy of rectal cancer.

Smad4 gene silencing enhances the chemosensitivity of human lymphoma cells to adriamycin via inhibition of the activation of transforming growth factor β signaling pathway

There are diverse investigations focused on the therapies of lymphoma. Our research was taken to identify the effects of lentiviral-mediated Smad4 gene silencing on chemosensitivity of human lymphoma cells to adriamycin (ADM) via transforming growth factor β (TGFβ) signaling pathway. Raji/ADM cells were cultured and infected with lentiviral particles Smad4-short hairpin (shRNA) and control-shRNA. Then, the messenger RNA (mRNA) and protein levels of TGFβ signaling pathway-related factors (Smad4, Smad3, cyclinE, cyclinD1, and p21) in Raji/ADM cells were determined. The effect of Smad4-shRNA on cell viability, invasion and migration, and apoptosis were also detected. Compared with the Raji group, increased mRNA and protein levels of Smad4, Smad3, cyclinE, cyclinD1, enhanced cell proliferation, migration and invasion as well as decreased mRNA, and protein levels of p21 and cell apoptosis rate were found in the Raji/ADM and control-shRNA groups. However, Smad4 gene silencing resulted in decreased mRNA and protein levels of Smad4, Smad3, cyclinE, and cyclinD1 along with inhibited cell proliferation, migration and invasion but increased expression of p21 together with cell apoptosis. Collectively, Smad4 gene silencing can inhibit the activation of TGFβ signaling pathway, thereby enhancing the chemosensitivity of human lymphoma cells to ADM.

Stepwise approach to SNP-set analysis illustrated with the Metabochip and colorectal cancer in Japanese Americans of the Multiethnic Cohort

BACKGROUND

Common variants have explained less than the amount of heritability expected for complex diseases, which has led to interest in less-common variants and more powerful approaches to the analysis of whole-genome scans. Because of low frequency (low statistical power), less-common variants are best analyzed using SNP-set methods such as gene-set or pathway-based analyses. However, there is as yet no clear consensus regarding how to focus in on potential risk variants following set-based analyses. We used a stepwise, telescoping approach to analyze common- and rare-variant data from the Illumina Metabochip array to assess genomic association with colorectal cancer (CRC) in the Japanese sub-population of the Multiethnic Cohort (676 cases, 7180 controls). We started with pathway analysis of SNPs that are in genes and pathways having known mechanistic roles in colorectal cancer, then focused on genes within the pathways that evidenced association with CRC, and finally assessed individual SNPs within the genes that evidenced association. Pathway SNPs downloaded from the dbSNP database were cross-matched with Metabochip SNPs and analyzed using the logistic kernel machine regression approach (logistic SNP-set kernel-machine association test, or sequence kernel association test; SKAT) and related methods.

RESULTS

The TGF-β and WNT pathways were associated with all CRC, and the WNT pathway was associated with colon cancer. Individual genes demonstrating the strongest associations were TGFBR2 in the TGF-β pathway and SMAD7 (which is involved in both the TGF-β and WNT pathways). As partial validation of our approach, a known CRC risk variant in SMAD7 (in both the TGF-β and WNT pathways: rs11874392) was associated with CRC risk in our data. We also detected two novel candidate CRC risk variants (rs13075948 and rs17025857) in TGFBR2, a gene known to be associated with CRC risk.

CONCLUSIONS

A stepwise, telescoping approach identified some potentially novel risk variants associated with colorectal cancer, so it may be a useful method for following up on results of set-based SNP analyses. Further work is required to assess the statistical characteristics of the approach, and additional applications should aid in better clarifying its utility.

miR144-3p inhibits PMVECs excessive proliferation in angiogenesis of hepatopulmonary syndrome via Tie2

BACKGROUND/AIM

Increasing evidence show microRNAs (miRNAs) are associated with hepatopulmonary syndrome (HPS). The aim of this study was to investigate the role of miR-144 in the angiogenesis of HPS, as well as to identify its underlying mechanism.

METHODS

The expression levels of miR-144-3p were assessed in pulmonary micro-vascular endothelial cells (PMVECs), as well as in lung tissues from rats with HPS. We predicted the potential target of miR-144-3p. Tyrosine kinase 2(Tie2) was identified as a target gene of miR144-3p, which has an essential role in the angiogenesis of lung vessel. In addition, the effects of miR-144-3p regulated on Tie2 was examined. The upregulation and down-regulation of miR-144-3p can affect the proliferation of PMVECs.

RESULTS

We found that the levels of miR-144-3p were frequently downregulated in HPS tissues and cell lines, and overexpression of miR-144-3p dramatically inhibited PMVECs proliferation and cell cycle. We further verified the Tie2 as a novel and direct target of miR-144-3p in HPS.

CONCLUSION

miR-144-3p can negatively regulate PMVECs proliferation by Tie2 expression. In addition, overexpression of miR-144-3p may prove beneficial as a therapeutic strategy for HPS treatment.

Genetic variants in the TGFβ-signaling pathway influence expression of miRNAs in colon and rectal normal mucosa and tumor tissue

The TGF-β signaling pathway is involved in regulation of cell growth, angiogenesis, and metastasis. We test the hypothesis that genetic variation in the TGF-β signaling pathway alters miRNA expression.We use data from 1188 colorectal cancer cases to evaluate associations between 80 SNPs in 21 genes.Seven variants eIF4E rs12498533, NFκB1 rs230510, TGFB1 rs4803455, TGFBR1 rs1571590 and rs6478974, SMAD3 rs3743343, and RUNX1 rs8134179 were associated with expression level of miRNAs in normal colorectal mucosa. RUNX2 rs12333172 and BMPR1B rs13134042 were associated with miRNAs in normal colon mucosa; eIF4EBP3 rs250425, SMAD3 rs12904944, SMAD7 rs3736242, and PTEN rs532678 were associated with miRNA expression in normal rectal mucosa. Evaluation of the differential expression between carcinoma and normal mucosa showed that SMAD3 rs12708491 and rs2414937, NFκB1 rs230510 and rs3821958, and RUNX3 rs6672420 were associated with several miRNAs for colorectal carcinoma. Evaluation of site-specific differential miRNA expression showed that BMPR1B rs2120834, BMPR2 rs2228545, and eIF4EBP3 rs250425 were associated with differential miRNA expression in colon tissue and SMAD3 rs12901071, rs1498506, and rs2414937, BMPR2 rs2228545, and RUNX2 rs2819854, altered differential miRNA expression in rectal tissue.These data support the importance of the TGF-β signaling pathway to the carcinogenic process, possibly through their influence on miRNA expression levels.

Infrequently expressed miRNAs influence survival after diagnosis with colorectal cancer

Half of miRNAs expressed in colorectal tissue are expressed < 50% of the population. Many infrequently expressed miRNAs have low levels of expression. We hypothesize that less frequently expressed miRNAs, when expressed at higher levels, influence both disease stage and survival after diagnosis with colorectal cancer (CRC); low levels of expression may be background noise.

We examine 304 infrequently expressed miRNAs in 1893 population-based cases of CRC with paired carcinoma and normal mucosa miRNA profiles. We evaluate miRNAs with disease stage and survival after adjusting for age, study center, sex, MSI status, and AJCC stage. These miRNAs were further evaluated with RNA-Seq data to identify miRNA::mRNA associations that may provide insight into the functionality of miRNAs.

Eleven miRNAs were associated with advanced disease stage among colon cancer patients (Q value = 0.10). Eight infrequently expressed miRNAs influenced survival if highly expressed in overall CRC. Of these, five increased likelihood of dying if they were highly expressed, i.e. miR-124-3p, miR-143-5p, miR-145-3p, miR31-5p, and miR-99b-5p, while three were associated with better survival if highly expressed, i.e. miR-362-5p, miR-374a-5p, and miR-590-5p. Thirteen miRNAs infrequently expressed in colon-specific carcinoma tissue were associated with CRC survival if highly expressed. Evaluation of miRNAs::mRNA associations showed that mRNA expression influenced by infrequently expressed miRNA contributed to networks and pathways shown to influence disease progression and prognosis.

Our large study enabled us to examine the implications of infrequently expressed miRNAs after removal of background noise. These results require replication in other studies. Confirmation of our findings in other studies could lead to important markers for prognosis.

Genetic Variants in the Insulin-like Growth Factor Pathway and Colorectal Cancer Risk in the Netherlands Cohort Study

Interrelationships between insulin-like growth factors (IGFs), hyperinsulinaemia, diabetes, and colorectal cancer (CRC) indicate involvement of IGFs in colorectal tumorigenesis. We investigated the CRC risk associated with 24 single nucleotide polymorphisms (SNPs) in 9 genes related to the IGF pathway and an IGF1 19-CA repeat polymorphism. Variants were selected from literature and genotyped in toenail DNA from 3,768 subcohort members and 2,580 CRC cases from the Netherlands Cohort Study, which has a case-cohort design (n = 120,852). We used the follow-up period 1986–2002. Eighteen SNPs were unequivocally associated with selected endpoints in the literature and unfavorable alleles were aggregated into a genetic sum score. Cox regression showed that a higher genetic sum score significantly increased CRC risk at all subsites, except the rectum, in men (highest vs. lowest tertile: HR for CRC = 1.36, 95% CI: 1.11, 1.65; P-trend = 0.002). Single SNPs (except the IGF1 SNP rs5742694) were not associated with risk. Models including the total number of IGF1 19-CA repeats showed CRC risk was halved at all subsites in women carrying <38 repeats but not >38 repeats (≤36 versus 38 repeats: HR for CRC = 0.44; 95% CI: 0.33, 0.58; P-trend < 0.001). These findings support a role for variants in IGF-related genes in colorectal tumorigenesis.

Vitamin D3 enhances the tumouricidal effects of 5-Fluorouracil through multipathway mechanisms in azoxymethane rat model of colon cancer

Background

Vitamin D3 and its analogues have recently been shown to enhance the anti-tumour effects of 5- Fluorouracil (5-FU) both in vitro and in xenograft mouse model of colon cancer. This study measured the potential mechanism(s) by which vitamin D3 could synergise the tumouricidal activities of 5-FU in azoxymethane (AOM) rat model of colon cancer.

Methods

Seventy-five male Wistar rats were divided equally into 5 groups: Control, AOM, AOM-treated by 5-FU (5-FU), AOM-treated by vitamin D3 (VitD3), and AOM-treated by 5-FU + vitamin D3 (5-FU/D). The study duration was 15 weeks. AOM was injected subcutaneously for 2 weeks (15 mg/kg/week). 5-FU was injected intraperitoneally in the 9th and 10th weeks post AOM (8 total injections were given: 12 mg/kg/day for 4 successive days, then 6 mg/kg every other day for another 4 doses) and oral vitamin D3 (500 IU/rat/day; 3 days/week) was given from week 7 post AOM till the last week of the study. The colons were collected following euthanasia for gross and histopathological examination. The expression of β-catenin, transforming growth factor-β1 (TGF-β1), TGF-β type 2 receptor (TGF-βR2), smad4, inducible nitric oxide synthase (iNOS), and heat shock protein-90 (HSP-90) proteins was measured by immunohistochemistry. In colonic tissue homogenates, quantitative RT-PCR was used to measure the mRNA expression of Wnt, β-catenin, Dickkopf-1 (DKK-1) and cyclooxygenase-2 (COX-2) genes, while ELISA was used to measure the concentrations of TGF-β1, HSP-90 and COX-2 proteins.

Results

Monotherapy with 5-FU or vitamin D3 significantly decreased the number of grown tumours induced by AOM (P < 0.05); however, their combination resulted in more significant tumouricidal effects (P < 0.05) compared with monotherapy groups. Mechanistically, vitamin D3/5-FU co-therapy significantly decreased the expression of Wnt, β-catenin, iNOS, COX-2 and HSP-90 and significantly increased the expression of DKK-1, TGF-β1, TGF-βR2, smad4 (P < 0.05), in comparison with their corresponding monotherapy groups.

Conclusions

Vitamin D3 and 5-FU synergise together and exhibit better anticancer effects by modulating Wnt/β-catenin pathway, TGF-β1 signals, iNOS, COX-2 and HSP-90. Further studies are required to illustrate the clinical value of vitamin D supplementation during the treatment of colon cancer with 5-FU in human patients.

Bone morphogenetic protein 2 inhibits the proliferation and growth of human colorectal cancer cells

Colorectal cancer (CRC) is one of the most deadly cancers worldwide. Significant progress has been made in understanding the molecular pathogenesis of CRC, which has led to successful early diagnosis, surgical intervention and combination chemotherapy. However, limited therapeutic options are available for metastatic and/or drug-resistant CRC. While the aberrantly activated Wnt/β-catenin pathway plays a critical initiating role in CRC development, disruption of the bone morphogenetic protein (BMP) pathway causes juvenile polyposis syndrome, suggesting that BMP signaling may play a role in CRC development. However, conflicting results have been reported concerning the possible roles of BMP signaling in sporadic colon cancer. Here, we investigated the effect of BMP2 on the proliferation, migration, invasiveness and tumor growth capability of human CRC cells. Using an adenovirus vector that overexpresses BMP2 and the piggyBac transposon-mediated stable BMP2 overexpression CRC line, we found that exogenous BMP2 effectively inhibited HCT116 cell proliferation and colony formation. BMP2 was shown to suppress colon cancer cell migration and invasiveness. Under a low serum culture condition, forced expression of BMP2 induced a significantly increased level of apoptosis in HCT116 cells. Using a xenograft tumor model, we found that forced expression of BMP2 in HCT116 cells suppressed tumor growth, accompanied by decreased cell proliferation activity. Taken together, our results strongly suggest that BMP2 plays an important inhibitory role in governing the proliferation and aggressive features of human CRC cells.

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.

Association of sedentary behavior with the expression levels of biomarkers in colorectal cancer: clinical analysis of 228 patients

There is an association between sedentary behavior and the risk of colorectal cancer (CRC), but the underlying mechanism is unclear. CRC is characterized by the changes in the expression levels of biomarkers, including voltage-gated proton channel Hv1, matrix-remodeling associated 5 (MXRA5), DEK (inducing positive supercoils into circular DNA) and protein inhibitor of activated signal transducer and activators of transcription 3 (PIAS3). Thus, sedentary behavior may affect the expression levels of these biomarkers in the colorectal tissue. Here, we recruited 228 CRC patients (128 males, 57.8 ± 7.8 years; 100 females, 57.7 ± 7.5 years) and 80 healthy subjects (48 males, 57.5 ± 6.8 years; 32 females, 56.9 ± 6.5 years) from March 7th, 2010 to May 6th, 2012. All the subjects were unrelated Han Chinese with the similar cultural and economic background. All the subjects were interviewed concerning sedentary time (sitting time categories: less than 1, 1-3, 4-6, and more than 6 h/day). The daily sedentary time of most CRC patients was more than 4 h/day, while the sedentary time of most healthy subjects was less than 3 h/day. The expression levels of Hv1, MXRA5 and DEK mRNAs and proteins were higher in CRC tissues and the levels of PIAS3 mRNA and protein were lower when the daily sedentary time was longer in CRC patients (p < 0.05). The daily sedentary time was correlated with the protein levels of CRC biomarkers. Furthermore, the sedentary time was positively related with body mass index but not daily calorie intake.

Long-chain omega-3 polyunsaturated fatty acid intake and risk of colorectal cancer

Research suggests that long-chain omega-3 polyunsaturated fatty acids (LC-PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have antineoplastic properties, yet evidence for association between LC-PUFAs and colorectal cancer (CRC) remains inconsistent. Using the VITamins And Lifestyle (VITAL) cohort, we evaluated how EPA/DHA intake, and its primary sources, fish oil supplement use and dark fish consumption, relate to CRC risk. A total of 68,109 Washington residents aged 50-76 completed a questionnaire between 2000-2002 and were followed for CRC through 2008 (n = 488). Persons using fish oil supplements on 4+ days/wk for 3+ yr experienced 49% lower CRC risk than nonusers (hazard ratio = 0.51, 95% CI = 0.26-1.00; P trend = 0.06). The association between fish oil use and decreased CRC risk was primarily observed for men (P interaction = 0.02; P trend men = 0.02; P trend women = 0.88) and for colon cancer (P difference = 0.05; P trend colon = 0.03; P trend rectum = 0.87). Although dark fish and total EPA + DHA intake were not associated with CRC risk overall, these associations varied by genetic risk (P interaction = 0.009 and 0.02, respectively), with inverse associations observed among low-moderate genetic risk groups and positive associations observed among high risk groups. Results suggest that associations between LC-PUFA intake and CRC may vary by gender, subsite, and genetic risk, providing additional insight into the potential role of LC-PUFAs in cancer prevention.

Identification of a microRNA expression signature for chemoradiosensitivity of colorectal cancer cells, involving miRNAs-320a, -224, -132 and let7g

BACKGROUND AND PURPOSE

Preoperative chemoradiotherapy (CRT) represents the standard treatment for locally advanced rectal cancer. Tumor response and progression vary considerably. MicroRNAs represent master regulators of gene expression, and may therefore contribute to this diversity.

MATERIAL AND METHODS

Genome-wide microRNA (miRNA) profiling was performed for 12 colorectal cancer (CRC) cell lines and an individual in vitro signature of chemoradiosensitivity was established. Functional relevance of selected miRNAs was established by transfecting miRNA-mimics into SW480 and SW837 cells. The prognostic value of selected miRNAs was assessed in 128 pretherapeutic patient biopsies.

RESULTS

Thirty-six miRNAs were identified to significantly correlate with sensitivity to CRT (Q < 0.05) including miR-320a and other miRNAs involved in the MAPK-, TGF- and Wnt-pathway. Transfection of selected miRNAs (let-7g, miR-132, miR-224, miR-320a) each induced a shift of sensitivity. High expression of let-7 g was associated with a good prognosis in rectal cancer patients (P = 0.03).

CONCLUSIONS

This is the first report of a miRNA expression signature for in vitro chemoradiosensitivity of CRC cell lines. Many of the identified miRNAs have not been linked to the response to CRT and may represent potential molecular targets to sensitize resistant cancers. If further validated, let7g expression may serve as predictive biomarker.

Transforming growth factor beta-1 C-509T polymorphism and cancer risk: a meta-analysis of 55 case-control studies

AIM

To investigate the association of transforming growth factor-beta 1 (TGF-β1) C-509T polymorphism and susceptibility to cancer by means of meta-analysis.

METHODS

An extensive search was performed to identify eligible case-control studies investigating such a link. The strength of the association between TGF-β1 C-509T polymorphism and cancer risk was assessed by pooled odds ratios (ORs) and 95%confidence intervals (95%CIs) in fixed or random effects models.

RESULTS

55 published case-control studies with a total number of 21,639 cases and 28,460 controls were included. Overall, there was no association between TGF-β1 C-509T and cancer risk in all genetic comparison models (TT vs. CC: OR=1.01, 95%CI=0.89-1.15; T vs. C: OR=1.01, 95%CI=0.94-1.07). However, a stratified analysis by cancer type indicated -509 T allele was significantly associated with decreased risk of colorectal cancer (CRC) (TT vs. CT/CC: OR=0.85, 95%CI=0.76-0.95), especially for Caucasians (TT vs. CT/CC: OR=0.83, 95%CI=0.71-0.98) and for population-based studies (TT vs. CT/CC: OR=0.78, 95%CI=0.68- 0.89).

CONCLUSION

This meta-analysis suggested that TGF-β1 C-509T polymorphism might contribute to a decreased risk on colorectal cancer susceptibility, especially for Caucasians.

Phenotypic and tumor molecular characterization of colorectal cancer in relation to a susceptibility SMAD7 variant associated with survival

The minor allele (G) of rs4939827, a SMAD7 (18q21) intronic variant, is associated with a lower risk of developing colorectal cancer (CRC) and poorer survival after diagnosis. Our objective was to evaluate the associations of this variant with different tumor phenotype and intratumoral molecular characteristics. We evaluated 1509 CRC cases and 2307 age-matched controls nested within the Nurses' Health Study and the Health Professionals Follow-up Study. We used the TaqMan assay to genotype rs4939827 and logistic regression to assess the association of rs4939827 with risk of CRC according to different phenotypic and molecular characteristics. We found that the minor allele (G) in rs4939827 (SMAD7, 18q21) was associated with a lower risk of developing tumor stage pT1 or pT2 CRC [multivariate odds ratio (OR), 0.73; 95% confidence interval (CI) 0.62-0.87] but not tumor stage pT3 or pT4 (multivariate OR, 1.07; 95% CI 0.93-1.23, P for heterogeneity = 1.2 × 10(-4)). The association between rs4939827 and CRC also significantly differed by methylation of RUNX3 (P for heterogeneity = 0.005). Among those with CRC, the minor allele (G) in rs4939827 was significantly associated with poorer overall survival (hazards ratio, 1.20; 95% CI, 1.02-1.42). We can conclude that the minor allele (G) of the germline intronic SMAD7 variant rs4939827 is associated with a lower risk of CRC with earlier tumor stage and CRC without methylation of the tumor suppressor RUNX3. These findings suggest that individuals with this SMAD7 variant that develop CRC are more probably to have tumors with greater invasiveness and methylation of RUNX3, which potentially contributes to their poorer observed survival.

Correlation between TGF-β1-509 C>T polymorphism and risk of digestive tract cancer in a meta-analysis for 21,196 participants

The association between transforming growth factor β1 (TGF-β1)-509 C>T and risk of digestive tract cancer (DTC) remained uncertain as previous studies reported conflicting results. The aim of this study was to assess the association by using a meta-analysis. The databases of MEDLINE, EMBASE and WANGFANG (Chinese database) were retrieved, and latest update was on 2nd February, 2012. Pooled odds ratio and 95% confidence interval (OR and 95% CI) were calculated by using a fixed- or random-effect model. Ultimately, twenty nine case-control studies with 8664 cases and 12,532 controls were included in this meta-analysis. Overall, there was no association between TGF-β1-509 C>T and risk of DTC in all genetic comparison models (OR and 95% CI: 0.96 and 0.81-1.15 for TT vs. CC, 0.98 and 0.91-1.05 for T carriers vs. C carriers). When subgroup analyses were conducted according to ethnicity, types of cancer and sample size, T allele was significantly associated with decreased risk of DTC for Caucasians and for large sample-sized studies, and was associated with decreased risk of colorectal cancer (OR and 95% CI for TT vs. CC: 0.82 and 0.70-0.97 for Caucasians, 0.80 and 0.68-0.98 for large sample-sized studies, 0.78 and 0.62-0.97 for colorectal cancer). This study indicated that TGF-β1-509 C>T polymorphism was probably associated with risk of DTC, especially for Caucasians. Because of modest limitation, our findings should be confirmed by future studies.

NELL-1-dependent mineralisation of Saos-2 human osteosarcoma cells is mediated via c-Jun N-terminal kinase pathway activation

PURPOSE

NELL-1 is a novel osteoinductive growth factor that has shown promising results for the regeneration of bone. Moreover, NELL-1 has been used successfully in bone regeneration in the axial, appendicular and calvarial skeleton of both small and large animal models. Despite increasing evidence of NELL-1 efficacy and future usefulness as an alternative to traditional bone graft substitutes, much has yet to be understood regarding the mechanisms of action of this novel protein. The activation of the mitogen-activated protein kinase (MAPK) pathway has been well studied in the setting of growth factor-mediated changes in osteogenic differentiation.

METHODS

In this study, we provide evidence of the involvement of MAPK signalling pathways in NELL-1-induced terminal osteogenic differentiation of Saos-2 human osteosarcoma cells. Activation of extracellular signal-regulated kinase (ERK1/2), P38 and c-Jun N-terminal kinase (JNK) pathways were screened with MAPK signalling protein array after recombinant human (rh)NELL-1 treatment. Next, the mineralisation and intracellular phosphate levels after rhNELL-1 stimulation were assessed in the presence or absence of specific MAPK inhibitors.

RESULTS

Results showed that rhNELL-1 predominantly increased JNK pathway activation. Moreover, the specific JNK inhibitor SP600125 blocked rhNELL-1-induced mineralisation and intracellular phosphate accumulation, whereas ERK1/2 and P38 inhibitors showed no effect.

CONCLUSIONS

Thus, activation of the JNK pathway is necessary to mediate terminal osteogenic differentiation of Saos-2 osteosarcoma cells by rhNELL-1. Future studies will extend these in vitro mechanisms to the in vivo effects of NELL-1 in dealing with orthopaedic defects caused by skeletal malignancies or other aetiologies.

Genetic variation in the transforming growth factor-β-signaling pathway, lifestyle factors, and risk of colon or rectal cancer

BACKGROUND

The transforming growth factor-β-signaling pathway has been identified as being involved in colorectal cancer.

OBJECTIVE

The aim of this study was to determine how diet and lifestyle factors in combination with genetic variation in the transforming growth factor-β-signaling pathway alters colorectal cancer risk.

DESIGN

We used data from 2 population-based case-control studies.

PATIENTS

Participants included patients with colon cancer (n = 1574) and controls (n = 1970) and patients with rectal cancer ( n = 791) and controls (n = 999).

MAIN OUTCOME MEASURES

The primary outcomes measured were newly diagnosed cases of colon or rectal cancer.

RESULTS

Colon and rectal cancer risk increased with the number of at-risk genotypes within the transforming growth factor-β-signaling pathway (OR 3.68, 95% CI 2.74,4.94 for colon cancer; OR 3.89, 95% CI 2.66,5.69 for rectal cancer). A high at-risk lifestyle score also resulted in significant increased risk with number of at-risk lifestyle factors (OR 2.99, 95% CI 2.32,3.85 for colon cancer; OR 3.37, 95% CI 2.24,5.07 for rectal cancer). The combination of high-risk genotype and high-risk lifestyle results in the greatest increase in risk (OR 7.89, 95% CI 4.45,13.96 for colon cancer; OR 8.75, 95% CI 3.66,20.89 for rectal cancer).

LIMITATIONS

The study results need validation in other large studies of colon and rectal cancer.

CONCLUSIONS

In summary, our data suggest that there is increased colon and rectal cancer risk with increasing number of at-risk genotypes and at-risk lifestyle factors. Although the integrity of the pathway can be diminished by a number of high-risk genotypes, this risk can be offset, in part, by maintaining a healthy lifestyle.

Meta-analyses of the associations between four common TGF-β1 genetic polymorphisms and risk of colorectal tumor

The associations between four common genetic polymorphisms of transforming growth factor-β1 (TGF-β1 -509 C > T, +869 T > C, +915 G > C, and -800 G > A) and risk of colorectal tumor (including adenoma and cancer) have been widely studied. To date, no conclusions could be available because of controversial results reported. Thus, we conducted a meta-analysis to further assess the associations. We searched the databases of Medline, Embase, and Wangfang to identify eligible studies, and latest update was on January 1, 2012. Odds ratio (OR) and 95% confidence interval (95%CI) were calculated to present the associations. Our meta-analysis indicated that TGF-β1 -509 C > T, +869 T > C, +915 G > C, and -800 G > A were not associated with risk of colorectal adenoma (OR = 0.89 for C carriers vs. TT for -509 C > T, 1.03 for C carriers vs. TT for +869 T > C, 1.09 for C carriers vs. GG for +915 G > C, and 1.19 for A carriers vs. GG for 800 G > A). However, C allele of TGF-β1 -509 C > T and A allele of -800 G > A were associated with increased risk of colorectal cancer (CRC), and OR (95%CI) was 1.23 (0.99-1.52) for CC vs. TT for -509 C > T and 6.64 (3.46-12.72) for A carriers vs. GG. The positive association between -509 C allele and risk of CRC was more obvious when subgroup analyses were conducted for population-based and large sample-sized studies as well as Caucasians. In contrast, we did not observed any associations between TGF-β1 +869 T > C, +915 G > C, and risk of CRC. This study indicated that C allele of TGF-β1-509 C > T and A allele of -800 G > A might contribute to the increased risk of CRC, and could be used as two of genetic marks for screening individuals at high risk of CRC. Because of modest limitation, large sample-sized studies were required to confirm the findings.

Upregulation of bone morphogenetic protein 4 is associated with poor prognosis in patients with hepatocellular carcinoma

Bone morphogenetic protein (BMP) 4 plays a crucial role in tumor invasion and metastasis of various human cancers. However, little is known about the correlation of BMP4 expression with clinical aggressiveness and prognosis in hepatocellular carcinoma (HCC). The aim of this study was to investigate the expression of BMP4 in HCC and determine its correlation with tumor progression and prognosis. Immunohistochemistry assay was used to determine the expression of BMP4 in HCC and corresponding paracarcinomatous tissues from 156 patients. The potential prognostic value of BMP4 was investigated by comparing the survival rates between the BMP4-positive and BMP4-negative HCC patients. Immunohistochemically, BMP4 protein expression in the HCC tissues (120/156, 76.9%) was significantly higher than that in the paracarcinomatous tissues (19/156, 12.2%, P < 0.01). The expression of BMP4 in HCC was associated with number of tumor nodules (P = 0.02), Edmondson grade (P = 0.03), TNM stage (P = 0.009), and vascular invasion (P = 0.006). In univariate survival analysis, the significant associations of the BMP4 protein overexpression with shortened patients' overall and disease-free survival were found (P = 0.001 and 0.006, respectively). Furthermore, its expression was found to be an independent factor for predicting both overall (P = 0.009) and disease-free survival (P = 0.022) of HCC in multivariate analysis. Our data suggest for the first time that BMP4 is overexpressed in HCC tissues and may also act as a novel marker for predicting the recurrence and prognosis of HCC patients after surgery.

Runx1 is a tumor suppressor gene in the mouse gastrointestinal tract

The Runx1 transcription factor plays an important role in tissue homeostasis through its effects on stem/progenitor cell populations and differentiation. The effect of Runx1 on epithelial differentiation of the secretory cell lineage of the colon was recently demonstrated. This study aimed to examine the role of Runx1 in tumor development in epithelial cells of the gastrointestinal tract. Conditional knockout mice that lacked Runx1 expression in epithelial cells of the GI tract were generated. These mice were crossed onto the Apc(Min) background, killed and their intestinal tumor phenotypes were compared with Apc(Min) Runx1 wild-type control mice. Apc-wild-type Runx1-mutant mice were also examined for tumor development. Colons from Runx1 knockout and wild-type mice were used for genome-wide mRNA expression analyses followed by gene-specific quantitative RT-PCR of whole colon and colon epithelium to identify Runx1 target genes. Runx1 deficiency in intestinal epithelial cells significantly enhanced tumorigenesis in Apc(Min) mice. Notably, epithelial Runx1 deficiency in Apc-wild-type mice was sufficient to cause tumor development. Absence of Runx1 was associated with global changes in the expression of genes involved in inflammation and intestinal metabolism, and with gene sets indicative of a metastatic phenotype and poor prognosis. Gene-specific analysis of Runx1-deficient colon epithelium revealed increased expression of genes linked to an expansion of the stem/progenitor cell population. These results identify Runx1 as a novel tumor suppressor gene for gastrointestinal tumors and support a role for Runx1 in maintaining the balance between the intestinal stem/progenitor cell population and epithelial differentiation of the GI tract.

Common colorectal cancer risk variants in SMAD7 are associated with survival among prediagnostic nonsteroidal anti-inflammatory drug users: a population-based study of postmenopausal women

Common single nucleotide polymorphisms (SNPs) in SMAD7 (18q21) have been linked to colorectal cancer (CRC) risk in genome-wide association studies, but little is known about their effects on survival. SMAD7 regulates gastrointestinal inflammation by inhibiting transforming growth factor-β (TGFB), which can act as both a tumor suppressor and a promoter of metastasis. Regular use of cyclooxygenase-2 (COX2) inhibitors, such as nonsteroidal anti-inflammatory drugs (NSAIDs), reduces the risk of developing CRC. Because COX2 overexpression reduces the growth suppressing effects of TGFB, we hypothesized that survival may depend on both SMAD7 genotype and prediagnostic NSAID use. Postmenopausal women, ages 50-74, diagnosed with incident invasive CRC from 1997 to 2002 were identified using the Seattle-Puget Sound Surveillance, Epidemiology, and End Results (SEER) cancer registry. Information on prediagnostic NSAID use and other risk factors was ascertained by interview, and women were followed-up for survival through December 31, 2009. Seven hundred and twenty-seven cases were genotyped for two GWAS hits in SMAD7 with minor allele frequency > 30%, one with minor allele associated with decreased risk (rs4939827) and one with minor allele associated with increased risk (rs4464148). Two hundred and forty-two deaths occurred, 160 attributable to CRC. Among those without distant disease at diagnosis, CRC-specific survival differed by genotype only for NSAID users: each minor allele of rs4939827 was associated with worse survival [hazard ratio (HR) = 2.67, 95% confidence interval (CI): 1.33-5.37] and each minor allele of rs4464148 was associated with better survival (HR = 0.41, CI 0.18-0.94). SMAD7 variants known to be important for CRC risk were associated with disease-specific survival among prediagnostic NSAID users.