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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Analysis of Geologic CO 2 Migration Pathways in Farnsworth Field, NW Anadarko Basin

This study reports on analyses of natural, geologic CO 2 migration paths in Farnsworth Oil Field, northern Texas, where CO 2 was injected into the Pennsylvanian Morrow B reservoir as part of enhanced oil recovery and carbon sequestration efforts. We interpret 2D and 3D seismic reflection datasets of the study site, which is located on the western flank of the Anadarko basin, and compare our seismic interpretations with results from a tracer study. Petroleum system models are developed to understand the petroleum system and petroleum- and CO 2 -migration pathways. We find no evidence of seismically resolvable faults in Farnsworth Field, but interpret a karst structure, erosional structures, and incised valleys. These interpretations are compared with results of a Morrow B well-to-well tracer study that suggests that inter-well flow is up-dip or lateral. Southeastward fluid flow is inhibited by dip direction, thinning, and draping of the Morrow B reservoir over a deeper, eroded formation. Petroleum system models predict a deep basin-ward increase in temperature and maturation of the source rocks. In the northwestern Anadarko Basin, petroleum migration was generally up-dip with local exceptions; the Morrow B sandstone was likely charged by formations both below and overlying the reservoir rock. Based on this analysis, we conclude that CO 2 escape in Farnsworth Field via geologic pathways such as tectonic faults is unlikely. Abandoned or aged wellbores remain a risk for CO 2 escape from the reservoir formation and deserve further monitoring and research.

58 GEOSCIENCES↗
DOE OSTI2017

Radionuclide Migration at a Plowshare Program Site: the Gasbuggy Underground Nuclear Test Site, San Juan County, New Mexico - 17019

Project Gasbuggy in northwest New Mexico was the first of three subsurface nuclear tests the U.S. Atomic Energy Commission conducted to evaluate the potential to enhance the production of natural gas from low-permeability geologic formations. In 1967, a 29-kiloton nuclear device was detonated in the Lewis Shale (marine shale and siltstone), 1,292 m below the land surface. The detonation vaporized a cavity into which overlying rock collapsed, forming a 101-m high rubble-filled chimney with a radius of 25 m. Explosion-generated fractures extended between 120 m and 150 m from the working point (detonation location). Most of the radionuclides generated from the explosion remain in the cavity melt glass or have decayed to negligible amounts; tritium radioactivity, however, is still high enough and potentially mobile enough to be of concern. Tritium is able to exchange with stable hydrogen and form liquid water and water vapor; under two-phase (liquid and gas) reservoir conditions the majority of tritium is stored as liquid water and volatilises only to restore equilibrium conditions as gas is removed. A numerical model was developed to examine the migration of tritium in both phases through the fractured shale and sandstone under present conditions. The results suggest that tritium has migrated only 110 m from the working point between 1967 and 2014. Although tritium is able to exchange between the gas and aqueous phases, the faster-diffusing gas phase is responsible for most of the tritium transport from the chimney. A hypothetical producing gas well located 340 m from the working point was added to the model to determine if tritiated water vapor (HTO) could migrate toward the well; results show that, because the low gas velocities could not compete with the high rate of radioactive decay, tritium would not reach the well. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Blocking Ion Migration Stabilizes the High Thermoelectric Performance in Cu 2 Se Composites

The applications of mixed ionic–electronic conductors are limited due to phase instability under a high direct current and large temperature difference. Here, it is shown that Cu 2 Se is stabilized through regulating the behaviors of Cu + ions and electrons in a Schottky heterojunction between the Cu 2 Se host matrix and in-situ-formed BiCuSeO nanoparticles. The accumulation of Cu + ions via an ionic capacitive effect at the Schottky junction under the direct current modifies the space-charge distribution in the electric double layer, which blocks the long-range migration of Cu + and produces a drastic reduction of Cu + ion migration by nearly two orders of magnitude. Moreover, this heterojunction impedes electrons transferring from BiCuSeO to Cu 2 Se, obstructing the reduction reaction of Cu + into Cu metal at the interface and hence stabilizes the β-Cu 2 Se phase. Furthermore, incorporation of BiCuSeO in Cu 2 Se optimizes the carrier concentration and intensifies phonon scattering, contributing to the peak figure of merit ZT value of ≈2.7 at 973 K and high average ZT value of ≈1.5 between 400 and 973 K for the Cu 2 Se/ BiCuSeO composites. Here, this discovery provides a new avenue for stabilizing mixed ionic–electronic conduction thermoelectrics, and gives fresh insights into controlling ion migration in these ionic-transport-dominated materials.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Cooperative Cluster Metalation and Ligand Migration in Zirconium Metal–Organic Frameworks

Abstract Cooperative cluster metalation and ligand migration were performed on a Zr‐MOF, leading to the isolation of unique bimetallic MOFs based on decanuclear Zr 6 M 4 (M=Ni, Co) clusters. The M 2+ reacts with the μ 3 ‐OH and terminal H 2 O ligands on an 8‐connected [Zr 6 O 4 (OH) 8 (H 2 O) 4 ] cluster to form a bimetallic [Zr 6 M 4 O 8 (OH) 8 (H 2 O) 8 ] cluster. Along with the metalation of Zr 6 cluster, ligand migration is observed in which a Zr–carboxylate bond dissociates to form a M–carboxylate bond. Single‐crystal to single‐crystal transformation is realized so that snapshots for cooperative cluster metalation and ligand migration processes are captured by successive single‐crystal X‐ray structures. In 3+ was metalated into the same Zr‐MOF which showed excellent catalytic activity in the acetaldehyde cyclotrimerization reaction. This work not only provides a powerful tool to functionalize Zr‐MOFs with other metals, but also structurally elucidates the formation mechanism of the resulting heterometallic MOFs.

Yuan, Shuai↗
DOE OSTI2023

Migration and Precipitation of Platinum in Anion‐Exchange Membrane Fuel Cells

Abstract Despite the recent progress in increasing the power generation of Anion‐exchange membrane fuel cells (AEMFCs), their durability is still far lower than that of Proton exchange membrane fuel cells (PEMFCs). Using the complementary techniques of X‐ray micro‐computed tomography (CT), Scanning Electron Microscopy (SEM) and Energy Dispersive X‐ray (EDX) spectroscopy, we have identified Pt ion migration as an important factor to explain the decay in performance of AEMFCs. In alkaline media Pt +2 ions are easily formed which then either undergo dissolution into the carbon support or migrate to the membrane. In contrast to PEMFCs, where hydrogen cross over reduces the ions forming a vertical “Pt line” within the membrane, the ions in the AEM are trapped by charged groups within the membrane, leading to disintegration of the membrane and failure. Diffusion of the metal components is still observed when the Pt/C of the cathode is substituted with a FeCo−N−C catalyst, but in this case the Fe and Co ions are not trapped within the membrane, but rather migrate into the anode, thereby increasing the stability of the membrane.

Raut, Aniket↗
DOE OSTI2019

Light hydrocarbon and noble gas migration as an analogue for potential CO 2 leakage: numerical simulations and field data from three hydrocarbon systems

Abstract Sites where anthropogenic CO 2 captured from industrial sources is stored in deep geological formations for climate change mitigation are required to show secure retention of the injected CO 2 . Monitoring, reporting, and verification (MRV) plans are needed to indicate that no CO 2 release has occurred. We explored the degree to which direct comparison between a surface anomaly and reservoir geochemistry using various geochemical parameters can be used for attribution. We used data collected on light hydrocarbons and noble gases throughout the sedimentary column at three CO 2 enhanced oil recovery (EOR) sites to understand the processes that may cause fluid evolution. Light hydrocarbon and noble gases were sampled from reservoirs, gas‐bearing intervals above reservoirs, and groundwater. Vertical profiles indicated that lighter components are relatively enriched during migration (i.e. chromatographic separation). Static and numerical models were designed to simulate episodic gas migration and geochemical alteration of these geochemical parameters from solubility and sorption. The effects of hydrocarbon solubility were minimal (Bernard ratio changes within 5.2%) although field data were within the range of expected alterations from sorption. Forward models of CO 2 migration and noble gas interactions showed that CO 2 stripping causes an enrichment of crustal noble gases. In areas where natural fluxes of CO 2 from depth are non‐existent, the occurrence of crustal noble gas signature may distinguish fugitive CO 2 from the reservoir from natural near‐surface sources, and could be considered to explain apparent fluid anomalies. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

Anderson, Jacob↗
DOE OSTI2019

Development of quantitative metrics of plume migration at geologic CO 2 storage sites

We develop plume migration metrics based on spatial moment analysis methods that quantify the spatio–temporal evolution of plumes at geologic CO 2 storage sites. The metrics are generalized to handle any 3–D scalar attribute field values. Within the geologic CO 2 storage context, these can be parameters such as CO 2 saturation, effective pressure, overpressure, dissolved CO 2 concentration, total dissolved solids, pH, and other attributes that are critical for assessing risks. Here, the metrics are comprehensive in that they can effectively handle and account for complex continuous and discontinuous plumes and intra–plume migration. We demonstrate the metrics on simulated CO 2 plumes injected into flat and tilted reservoirs with homogeneous and heterogeneous permeability fields. Using these idealized reservoir scenarios, we demonstrate the information that the metrics extract, showing that the metrics elucidate nuances in plume migration not apparent by standard approaches to the scalar fields values.

03 NATURAL GAS↗
DOE OSTI2020

Modeling CO 2 plume migration using an invasion-percolation approach that includes dissolution

Geological carbon dioxide (CO 2 ) sequestration has been proposed as a viable technique to decrease effective emissions of CO 2 into the atmosphere. However, the security of this sequestration is tied to our understanding of the long-term migration of CO 2 in subsurface. The dissolution of CO 2 in the reservoir brine is one of the main long-term trapping mechanisms. However, the assumptions used in large-scale reservoir simulations usually lead to an overestimation of the dissolution volume. We propose a modified approach based on the macroscopic invasion-percolation (MIP) theory that allows the dissolution of CO 2 into brine. We used a high-resolution geological model to compare the Darcy-, modified MIP-, and classic MIP-based simulation results. We observed a significant shrinkage in the nonaqueous plume volume when dissolution is considered during the MIP simulation. In the case of Darcy-based simulation, the plume was completely trapped inside the reservoir with limited migration even after a thousand-year simulation. On the other hand, the majority of the plume migrated out of the simulated reservoir in the case of MIP. Our approach provides more realistic estimation of the dissolution volume and nonaqueous plume extent while leveraging the computational efficiency enjoyed by MIP.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Hydride Migration within RhH 2 Ag 19 Superatom: A Combined Neutron Diffraction and DFT Analysis

Abstract An investigation combining neutron diffraction and DFT allows determining the most likely hydride migration pathway within the icosahedral metal framework of [RhH 2 Ag 19 {S 2 P(O n Pr) 2 } 12 ] (RhH 2 Ag 19 ). Starting from the experimentally derived solid‐state structures, a computational analysis is able to reveal an energetically favorable migration pathway with a maximum energy barrier of 4.2 kcal mol −1 . The two hydrides migrate simultaneously within the Rh@Ag 12 icosahedral core, traversing several positional isomers. This study expands the understanding of hydride dynamics in nanoclusters and provides critical insights into the structural flexibility of the superatom framework. These findings have significant implications for hydrogen storage, catalysis, and the design of advanced hydride‐containing materials.

Chemistry↗
DOE OSTI2019

Dioscin-6’-O-acetate impairs migration of lung cancer cells through attenuations of MMP-2 and MMP-9 via NF-κB suppression

More than 90% of the cancer-associated mortality is attributed to its metastasis. Numerous studies demonstrated that natural steroidal saponins from plants had the capacity to inhibit lung cancer metastasis. Dioscin-6’-O-acetate (DA) was a novel steroidal saponin first obtained from the rhizomes of Dioscorea althaeoides R. Knuth. Our previous study indicated that it suppressed lung cancer cell proliferation via inducing cell-cycle arrest and enhancing caspase-dependent apoptosis. Until now, there were still no reports on its anti-migration activity. In the present study, we further verified the anti-proliferation and apoptosis-inducing effects and investigated the anti-migration effects of DA on human NSCLC (NCI-H460, NCI-H1299, NCI-H520) and SCLC (NCI-H446) cells for the first time. To clarify the possible mechanisms, western blot and/or RT-PCR analysis were used. The results revealed that DA treatment increased the levels of caspase 3, 8, 9, and Bax and markedly decreased the expression of bcl-2, PCNA, MMP-2, MMP-9, and NF-κB. Docking study indicated that DA presented strong affinity with the key metastasis-related proteins, such as MMP-2, MMP-9, and NF-κB. We proposed that DA might suppress lung cancer proliferation by downregulating PCNA, induce lung cancer apoptosis via activation of caspase-dependent apoptosis pathways, and inhibit lung cancer migration possibly by targeting MMP-2/9 through NF-κB signaling suppression. The findings would provide the foundation for the clinical use of DA in future.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Distribution and migration mechanism of fluoride in groundwater in the Manas River Basin, Northwest China

Elevated fluoride (F) concentration in groundwater is posing a public health risk in the Manas River Basin (MRB), Northwest China. Based on the characterization of regional groundwater flow, 90 groundwater samples from aquifers were analyzed, along with top-soil leachate and pore-water samples from aquitards. Stable oxygen (δ{sup 18}O) and hydrogen isotopes, radiocarbon and hydrochemical analyses of the groundwater and pore-water samples were conducted to trace groundwater hydrological and hydrochemical processes and thereby understand the distribution and migration mechanism of F. The groundwater is recharged by meteoric precipitation through vapor condensation processes in the Tianshan Mountains. The F concentration in groundwater samples from this basin ranged from 0.11 to 48.15 mg/L (mean 2.56 mg/L). In 37 of the 90 groundwater samples, the F concentrations were above the safe level for drinking water. The F concentrations progressively increased with the residence time and well depths in the northwest of the alluvial-fluvial plain, where groundwater is overexploited for agricultural and domestic use. Positive correlations between F and sodium (Na)/calcium (Ca) indicate that the enrichment and migration of F are influenced by cation exchange processes under high-Na and alkaline pH conditions. The relationships between δ{sup 18}O and F and chloride (Cl) concentrations were nonlinear due to leaching and mixing processes. This shows that vertical leaching by irrigation return flow and mixing with pore water are the dominant processes driving the migration of F in the groundwater flow system of MRB, in addition to geochemical processes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Non-radiative luminescence decay with self-trapped hole migration in strontium titanate: Interplay between optical and transport properties

A novel model for the non-radiative decay of self-trapped excitons (STEs) in the advanced functional oxide SrTiO3 is proposed and supported by experimental observations. The study is based on the initial ionoluminescence stage for STE emission at 2.5 eV, and its dependence on temperature and electronic excitation rate under energetic heavy-ion irradiation. For all temperatures, this initial stage reaches rapidly a quasi-steady level, and then decreases as induced-structural damage increases. The quasi-steady luminescence exhibits a linear dependence on the excitation rate, suggesting a constant efficiency for STEs formation. An activation energy of 55 meV, essentially independent of the incident ion mass and energy of projectile-ion, is deduced from an Arrhenius-type relationship with irradiation temperature. This energy is in good agreement with experimental values, measured for non-radiative STE decay under ns-laser pulse excitation, and reasonably consistent with density functional theory calculations for migration of self-trapped holes (STHs) described by a small-polaron adiabatic hopping model. A new mechanism dealing with a non-radiative contribution to the STE transition is discussed, consisting of STH migration through thermally-activated hopping and annihilation with the STE-electron. Luminescence kinetics from the chromium intrinsic impurity strongly supports this model, being consistent with the annihilation of Cr 3+ centers through recombination with migrating STHs.

luminescence↗
DOE OSTI2014

c-Cbl regulates αPix-mediated cell migration and invasion

Highlights: • c-Cbl ubiquitinates αPix for proteasome-mediated degradation. • C6 and A172 glioma cells lack c-Cbl, which leads to stabilization of αPix. • The accumulated αPix promotes migration and invasion of the cancer cells. • The lack of c-Cbl in the cells appears responsible for their malignant behavior. - Abstract: c-Cbl, a RING-type ubiquitin E3 ligase, down-regulates receptor tyrosine kinases, including EGF receptor, and inhibits cell proliferation. Moreover, c-Cbl mutations are frequently found in patients with myeloid neoplasm. Therefore, c-Cbl is known as a tumor suppressor. αPix is expressed only in highly proliferative and mobile cells, including immune cells, and up-regulated in certain invasive tumors, such as glioblastoma multiforme. Here, we showed that c-Cbl serves as an ubiquitin E3 ligase for proteasome-mediated degradation of αPix, but not βPix. Remarkably, the rat C6 and human A172 glioma cells were unable to express c-Cbl, which leads to a dramatic accumulation of αPix. Depletion of αPix by shRNA markedly reduced the ability of the glioma cells to migrate and invade, whereas complementation of shRNA-insensitive αPix promoted it. These results indicate that c-Cbl negatively regulates αPix-mediated cell migration and invasion and the lack of c-Cbl in the C6 and A172 glioma cells is responsible for their malignant behavior.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Rab25 upregulation correlates with the proliferation, migration, and invasion of renal cell carcinoma

Renal cell carcinoma (RCC) is a common urological cancer with a poor prognosis. A recent cohort study revealed that the median survival of RCC patients was only 1.5 years and that <10% of the patients in the study survived up to 5 years. In tumor development, Rab GTPase are known to play potential roles such as regulation of cell proliferation, migration, invasion, communication, and drug resistance in multiple tumors. However, the correlation between Rabs expression and the occurrence, development, and metastasis of RCC remains unclear. In this study, we analyzed the transcriptional levels of 52 Rab GTPases in RCC patients. Our results showed that high levels of Rab25 expression were significantly correlated with RCC invasion classification (P < 0.01), lymph-node metastasis (P < 0.001), and pathological stage (P < 0.01). Conversely, in 786-O and A-498 cells, knocking down Rab25 protein expression inhibited cell proliferation, migration, and invasion. Our results also demonstrated that Rab25 is a target gene of let-7d, and further suggested that Rab25 upregulation in RCC is due to diminished expression of let-7d. These findings indicate that Rab25 might be a novel candidate molecule involved in RCC development, thus identifying a potential biological therapeutic target for RCC. - Highlights: • The transcriptional levels of 52 Rab GTPases were analyzed in renal cell carcinoma (RCC). • High levels of Rab25 expression were significantly correlated with clinicopathological factors of RCC. • Knockdown of Rab25 protein expression reduced RCC cells proliferation, migration, and invasion. • Rab25 is a target gene of let-7d in RCC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

The role of microRNA-1274a in the tumorigenesis of gastric cancer: Accelerating cancer cell proliferation and migration via directly targeting FOXO4

MicroRNAs (miRNAs) are a series of 18–25 nucleotides length non-coding RNAs, which play critical roles in tumorigenesis. Previous study has shown that microRNA-1274a (miR-1274a) is upregulated in human gastric cancer. However, its role in gastric cancer progression remains poorly understood. Therefore, the current study was aimed to examine the effect of miR-1274a on gastric cancer cells. We found that miR-1274a was overexpressed in gastric cancer tissues or gastric cancer cells including HGC27, MGC803, AGS, and SGC-7901 by qRT-PCR analysis. Transfection of miR-1274a markedly promoted gastric cancer cells proliferation and migration as well as induced epithelial–mesenchymal transition (EMT) of cancer cells. Our further examination identified FOXO4 as a target of miR-1274a, which did not influence FOXO4 mRNA expression but significantly inhibited FOXO4 protein expression. Moreover, miR-1274a overexpression activated PI3K/Akt signaling and upregulated cyclin D1, MMP-2 and MMP-9 expressions. With tumor xenografts in mice models, we also showed that miR-1274a promoted tumorigenesis of gastric cancer in vivo. In all, our study demonstrated that miR-1274a prompted gastric cancer cells growth and migration through dampening FOXO4 expression thus provided a potential target for human gastric cancer therapy. - Highlights: • MiR-1274a expression was augmented in gastric cancer. • MiR-1274a promoted proliferation, migration and induced EMT in cancer cells. • MiR-1274a directly targeted FOXO4 expression. • MiR-1274a triggered PI3K/Akt signaling in cancer cells. • MiR-1274a significantly increased tumor xenografts growth.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Fenofibrate suppressed proliferation and migration of human neuroblastoma cells via oxidative stress dependent of TXNIP upregulation

There are no appropriate drugs for metastatic neuroblastoma (NB), which is the most common extra-cranial solid tumor for childhood. Thioredoxin binding protein (TXNIP), the endogenous inhibitor of ROS elimination, has been identified as a tumor suppressor in various solid tumors. It reported that fenofibrate exerts anti-tumor effects in several human cancer cell lines. However, its detail mechanisms remain unclear. The present study assessed the effects of fenofibrate on NB cells and investigated TXNIP role in its anti-tumor mechanisms. We used MTT assay to detect cells proliferation, starch wound test to investigate cells migration, H{sub 2}DCF-DA to detect intracellular ROS, siRNA to interfere TXNIP and peroxisome proliferator-androgen receptor-alpha (PPAR-α) expression, western blot to determine protein levels, flow cytometry to analyze apoptosis. Fenofibrate suppressed proliferation and migration of NB cells, remarkably increased intracellular ROS, upregulated TXNIP expression, promoted cell apoptosis. Furthermore, inhibition of TXNIP expression attenuated anti-tumor effects of fenofibrate, while inhibition of PPAR-α had no influences. Our results indicated the anti-tumor role of fenofibrate on NB cells by exacerbating oxidative stress and inducing apoptosis was dependent on the upregulation of TXNIP. - Highlights: • We found that fenofibrate suppressed proliferation and migration of NB cells. • We found that fenofibrate remarkably increased intracellular ROS, upregulated TXNIP expression, and promoted cell apoptosis. • Inhibition of TXNIP expression attenuated anti-tumor effects of fenofibrate, while inhibition of PPAR-α had no influences. • Our results indicated the anti-tumor role of fenofibrate on NB cells was dependent on the upregulation of TXNIP.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Overexpression of miR-206 suppresses glycolysis, proliferation and migration in breast cancer cells via PFKFB3 targeting

miRNAs, sorting as non-coding RNAs, are differentially expressed in breast tumor and act as tumor promoters or suppressors. miR-206 could suppress the progression of breast cancer, the mechanism of which remains unclear. The study here was aimed to investigate the effect of miR-206 on human breast cancers. We found that miR-206 was down-regulated while one of its predicted targets, 6-Phosphofructo-2-kinase (PFKFB3) was up-regulated in human breast carcinomas. 17β-estradiol dose-dependently decreased miR-206 expression as well as enhanced PFKFB3 mRNA and protein expression in estrogen receptor α (ERα) positive breast cancer cells. Furthermore, we identified that miR-206 directly interacted with 3′-untranslated region (UTR) of PFKFB3 mRNA. miR-206 modulated PFKFB3 expression in MCF-7, T47D and SUM159 cells, which was influenced by 17β-estradiol depending on ERα expression. In addition, miR-206 overexpression impeded fructose-2,6-bisphosphate (F2,6BP) production, diminished lactate generation and reduced cell proliferation and migration in breast cancer cells. In conclusion, our study demonstrated that miR-206 regulated PFKFB3 expression in breast cancer cells, thereby stunting glycolysis, cell proliferation and migration. - Highlights: • miR-206 was down-regulated and PFKFB3 was up-regulated in human breast carcinomas. • 17β-estradiol regulated miR-206 and PFKFB3 expression in ERα+ cancer cells. • miR-206directly interacted with 3′-UTR of PFKFB3 mRNA. • miR-206 fructose-2,6-bisphosphate (F2,6BP) impeded production and lactate generation. • miR-206 reduced cell proliferation and migration in breast cancer cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Down-regulation of TCF21 by hypermethylation induces cell proliferation, migration and invasion in colorectal cancer

Epigenetic alteration induced loss function of the transcription factor 21 (TCF21) has been associated with different types of human cancers. However, the epigenetic regulation and molecular functions of TCF21 in colorectal cancer (CRC) remain unknown. In this study, TCF21 expression levels and methylation status of its promoter region in CRC cell lines (n = 5) and CRC tissues (n = 151) as well as normal colorectal mucosa (n = 30) were assessed by RTq-PCR and methylation analysis (methylation specific PCR, MSP and bisulfite sequencing PCR, BSP), respectively. The cellular functions of TCF21 on CRC cell proliferation, apoptosis, invasion and migration were investigated in vitro. Our data revealed that TCF21 was frequently silenced by promoter hypermethylation in both tested CRC cell lines and primary CRC, and correlation analysis between methylation status and clinicopathologic parameters found that TCF21 methylation was significantly correlated with lymph node invasion (P = 0.013), while no significant correlation was found in other parameters. In addition, demethylation treatment resulted in re-expression of TCF21 in CRC cell lines, and cellular function experiments revealed that restoration of TCF21 inhibited CRC cell proliferation, promoted apoptosis and suppressed cell invasion and migration, suggesting that TCF21 may function as a tumor suppressor gene, which is downregulated through promoter hypermethylation in CRC development. - Highlights: • TCF21 was frequently silenced by promoter DNA methylation in CRC cells. • TCF21 was frequently methylated in primary CRC and significantly correlated with metastasis. • Restoration of TCF21 promotes cell apoptosis of CRC cells. • Restoration of TCF21 inhibits cell invasion and migration of CRC cells.

60 APPLIED LIFE SCIENCES↗