Association study between genome-wide significant variants of vitamin B12 metabolism and gastric cancer in a han Chinese population.

Gastric cancer is one of the leading causes of cancer mortality worldwide. Accumulating evidence suggests that vitamin B12 plays an important role in the development of gastric cancer. Genome-wide association studies on metabolites in the one-carbon metabolism pathway identified several vitamin B12-related polymorphisms. Therefore, we investigated the association between variants within vitamin B12-related genes and gastric cancer in a Han Chinese population. Eight variants within the genome were significant vitamin B12-related genes, and they were selected for analysis in this case-control study. This study used a total of 492 gastric cancer patients and 550 noncancer controls. The variant rs526934 from the TCN1 gene was associated with an increased risk of developing gastric cancer. Increased risks of gastric cancer occurrence were observed in the minor G allele (OR = 1.25, 95% CI = 1.03-1.52, P = 0.031) and GG genotype (OR = 2.06, 95% CI = 1.24-3.42, P = 0.0043) compared with the wild-type A allele and AA-GA genotype, respectively. In the haplotypic analysis, we found that the CUBN haplotypes were associated with an altered gastric cancer risk. The rs1801222T/rs11254363A (OR = 1.40, 95% CI = 1.05-1.86, P = 0.021) and rs1801222C/rs11254363G (OR = 4.39, 95% CI = 2.32-8.30, P < 0.0001) haplotypes exhibited an increased gastric cancer risk, while rs1801222T/rs11254363G showed protective effects against gastric cancer (OR = 0.43, 95% CI = 0.25-0.73, P = 0.002) compared with the wild-type rs1801222C/rs11254363A haplotype. The circulating vitamin B12 concentration-related variants were associated with the occurrence of gastric cancer. This finding shed light on the unexpected role of vitamin B12 metabolism genes in gastric carcinogenesis and highlighted the interplay of diet, genetics, and human cancers.

A novel method for simultaneously measuring boronophenylalanine uptake in brain tumor cells and number of cells using inductively coupled plasma atomic emission spectroscopy.

Boron neutron capture therapy (BNCT) combines neutron irradiation with boron compounds that are selectively uptaken by tumor cells. Boronophenylalanine (BPA) is a boron compound used to treat malignant brain tumors. The determination of boron concentration in cells is of great relevance to the field of BNCT. This study was designed to develop a novel method for simultaneously measuring the uptake of BPA by U87 and U251 cells (two brain tumor cell lines) and number of cells using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results revealed a linear correlation between phosphorus intensity and the numbers of U87 and U251 cells, with correlation coefficients (R2) of 0.9995 and 0.9994, respectively. High accuracy and reliability of phosphorus concentration standard curve were also found. Using this new method, we found that BPA had no significant effect on phosphorus concentration in either U87 or U251 cells. However, BPA increased the boron concentration in U87 and U251 cells in a concentration-dependent manner, with the boron concentration in U87 cells being higher than that in U251 cells. In both U87 and U251 cells, boron was mainly distributed in the cytoplasm and nucleus, accounting for 85% and 13% of the total boron uptake by U87 cells and 86% and 11% of the total boron uptake by U251 cells, respectively. In the U87 and U251 cell-derived xenograft (CDX) animal model, tumor exhibited higher boron concentration values than blood, heart, liver, lung, and brain, with a tumor/blood ratio of 2.87 for U87 cells and 3.11 for U251 cells, respectively. These results suggest that the phosphorus concentration in U87 and U251 cells can represent the number of cells and BPA is easily uptaken by tumor cells as well as in tumor tissue.

KIF22 Promotes Development of Pancreatic Cancer by Regulating the MEK/ERK/P21 Signaling Axis.

The study is aimed at exploring the potential biological process and molecular mechanism of KIF22 involved in the development and progression of pancreatic cancer. First, we used the GEPIA database and tissue qRT-PCR to examine the expression of KIF22 mRNA in pancreatic cancer. Meanwhile, immunohistochemistry revealed the presence of KIF22 in 71 pancreatic cancer tissues versus 30 paracarcinoma tissues. Then, we also explored the relationship between KIF22 expression level and clinical prognosis. Furthermore, in pancreatic cancer cells, we silenced KIF22 by transfecting KIF22 SiRNA, and we investigated the effect of KIF22 on the proliferation of pancreatic cancer cells with MTT and colony formation assays. Finally, we used Gene Set Enrichment Analysis (GSEA) to look at the effect of KIF22 on the cell cycle regulation of pancreatic cancer cells, and we used Western blot to look at the relationship between KIF22 and the phosphorylated MEK1/2, ERK1/2 (p-MEK1/2, p-ERK1/2), and the cyclin-dependent kinase inhibitor (P21). In this study, we found that KIF22 was highly expressed in pancreatic cancer tissues, and patients with high expression of KIF22 demonstrated significantly worse clinical prognosis outcomes (P < 0.05). When the KIF22 gene was silenced in pancreatic cancer cells (PANC-1 and MIA PaCa-2), the cells' ability to proliferate was significantly reduced. Furthermore, GSEA confirmed that KIF22 is involved in cell cycle regulation in pancreatic cancer patients (FDR = 0.00158, P < 0.0001). Besides, the level of KIF22 expression was positively correlated with Ki67 (r = 0.8043, P < 0.0001), and KIF22 can promote the transmutation of G1/S. The expression of p-MEK1/2 and p-ERK1/2 was significantly downregulated, while P21 expression was significantly upregulated (P < 0.05). According to our findings, KIF22 is highly expressed in pancreatic cancer and demonstrates a poor clinical prognosis. It regulates the cell cycle via the MEK/ERK/P21 signaling axis and promotes the development of pancreatic cancer.

Exploration of the Wound Healing Potential of Thermoplastic Polyurethane Electrospun Membrane Incorporated with Phenolic Acids in Spenceria ramalana Trimen.

Wound healing process is usually accompanied by infection and the wound dressing loaded with antibiotics is usually used to treat skin wound. However, the intensive use of antibiotics may lead to development of resistance and the antibiotic resistance has become a major global problem. Finding new wound dressing with sustained antibacterial property to overcome the problem of resistance is one of clinical challenge. In this work, phenolic acids in Spenceria ramalana Trimen and sliver nanoparticle incorporated thermoplastic polyurethane nanofibrous membrane (TPU/AgNPs/TPA) are fabricated via electrospinning. The TPU/AgNPs/TPA membrane exhibits excellent physicochemical properties with uniform morphology, good mechanical capacity, and appropriate hydrophilia providing suitable environment for wound healing. Moreover, the TPU/AgNPs/TPA membrane shows mild antioxidant property and exhibits continuous antibacterial activity against Staphylococcus aureus and Escherichia coli especially against drug-resistant E. coli. The antibacterial efficiency is as high as 99% lasting for 36 h. Furthermore, the TPU/AgNPs/TPA membrane used as wound dressing can accelerate wound healing through downregulating TNF-α and IL-1ß and upregulating vascular endothelial growth factor and epidermal growth factor. Therefore, the TPU/AgNPs/TPA membrane presented in this work with good antibacterial activity is an excellent wound dressing and has great potential in wound healing applications to overcome the problem of resistance.

Lonicera rupicola Hook.f.et Thoms flavonoids ameliorated dysregulated inflammatory responses, intestinal barrier, and gut microbiome in ulcerative colitis via PI3K/AKT pathway.

BACKGROUND: Lonicera rupicola Hook.f.et Thoms (LRH) is used as a customary medicinal herb in Tibetans. And LRH flavonoids have excellent anti-inflammatory and antioxidant pharmacological activities. However, the specific effects of LRH and its mechanism remain unknown, and there is a deficiency of systematic research, leading to the waste of LRH as a medicinal resource. PURPOSE: In this study, in an attempt to rationalize the development and utilization of Tibetan herbal resources, the therapeutic efficacy and the underlying molecular mechanisms of LRH flavonoids on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) were investigated, establishing the favorable basis for the pharmacodynamic material basis of LRH and providing a scientific basis for the discovery of new drugs for the treatment of UC. METHODS: Firstly, ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was used for identification and detection of the flavonoid components of LRH. Meanwhile, their potential targets, biological functions and signaling pathways were predicted with the assistance of network pharmacology analysis. Subsequently, pharmacological efficacy of LRH were evaluated by body weight loss, colon length, disease activity index (DAI), histology observation and the expression levels of inflammatory mediators, messenger RNA (mRNA) and tight junction proteins. Moreover, in the present investigation, we also profiled the gut microbiome via high-throughput sequencing of the V3-V4 region of 16S ribosomal DNA (rDNA) for bacterial community composition and diversity by Illumina MiSeq platforms. Finally, the key regulatory proteins in the PI3K/AKT pathways were measured to investigate their underlying molecular mechanisms. RESULTS: A total of 37 LRH flavonoid components were identified and detected by UPLC-MS/MS, and 12 potential active components were obtained after screening. 137 of their common targets with UC were further predicted. GO and KEGG pathway enrichment analysis and molecular docking experiments demonstrated that LRH flavonoids could interfere with UC through "multi-component-multi-target-multi-pathway". In the animal experiments, LRH flavonoids could significantly attenuate UC as demonstrated by reducing the body weight loss and DAI, restoring colon length, decreasing oxidative stress, and improving the intestinal epithelial cell barrier. The mRNA and proteins expression levels of inflammatory mediators were returned to dynamic balance following LRH flavonoids treatment. 16S rDNA sequence analysis indicated that LRH flavonoids promoted the recovery of gut microbiome. And the PI3K/AKT pathway was significantly suppressed by LRH flavonoids. CONCLUSIONS: LRH flavonoids exhibited multifaceted protective effects against DSS-induced UC in mice through mitigating colon inflammation and oxidative stress, restoring epithelial barrier function, and improving the gut microenvironment potentially through modulation of the PI3K/AKT pathway. This finding demonstrated that LRH flavonoids possessed great potential for becoming an excellent drug for the treatment of UC.

Evaluation of Pharmacokinetics of Boronophenylalanine and Its Uptakes in Gastric Cancer.

Boron neutron capture therapy (BNCT), a cellular-level particle radiation therapy, combines boron compounds selectively delivered to tumor tissue with neutron irradiation. Boronophenylalanine (BPA) is a boron compound widely used in malignant melanoma, malignant brain tumors, and recurrent head and neck cancer. However, neither basic nor clinical research was reported for the treatment of gastric cancer using BPA. Selective distribution of boron in tumors rather than that in blood or normal tissue prior to neutron irradiation is required for the successful treatment of BNCT. This study evaluated the pharmacokinetics and safety of 10B-labeled BPA (10B-BPA, abbreviated as BPA) and its uptakes in gastric cancer. Pharmacokinetics and safety were evaluated in Sprague-Dawley (SD) rats intravenously injected with BPA. The uptakes of boron in gastric cancer cell line MKN45 and in cell-derived xenografts (CDX) and patient-derived xenografts (PDX) animal models were measured. The results showed that the boron concentration in the blood of rats decreased fast in the first 30 min followed by a steady decrease following the observation time, having a half-life of 44.11 ± 8.90 min and an AUC-last of 815.05 ± 62.09 min×µg/ml. The distribution of boron in different tissues (heart, liver, lung, stomach, and small intestine) of rats revealed a similar pattern in blood except for that in the brain, kidney, and bladder. In MKN45 cells, boron concentration increased in a time- and concentration-dependent manner. In both CDX and PDX animal models, the boron is preferentially distributed in tumor tissue rather than in blood or normal tissues. In addition, BPA had no significant adverse effects in rats. Taken together, the results suggested that BPA revealed a fast decrease in boron concentration in rats and is more likely to distribute in tumor cells and tissue.

Construction and Validation of a Novel Prognostic Signature for Intestinal Type of Gastric Cancer.

BACKGROUND: Intestinal type of gastric cancer (IGC) is the largest subtype of gastric cancer (GC) by Lauren classification. The purpose of this present study was to construct a prognostic signature for IGC patients, based on the high-grade dysplasia (HGD) and IGC tissues, to improve and enhance the prognostic accuracy. METHODS: The microarray datasets and associated clinical characteristics of HGD and IGC were obtained from the Gene Expression Omnibus (GEO) database. Based on the differential expression analysis between HGD and IGC, the prognostic-related differential expression genes (DEGs) were identified in a training set by univariate COX regression analysis. The least absolute shrinkage and selection operator (LASSO) regression was used to construct an optimal prognostic signature. The enrichment analysis was performed by using Gene Set Enrichment Analysis (GSEA). The performance of the nomogram was assessed by the calibration curve and concordance index (C-index). The results were validated by using a testing set. RESULTS: We identified 35 prognostic-related DGEs in the training set. The nine-gene signature was established by LASSO analysis. The nine-gene signature was an independent risk factor in both the training and testing sets. The areas under the curve (AUC) values of receiver operating characteristic (ROC) analysis were 0.733 and 0.700 for the training and testing sets, respectively. In GSEA analysis, the gene expression in high-risk group was enriched in hedgehog signaling, epithelial mesenchymal transition, and angiogenesis. The nomogram for IGC showed good performance with C-index of 0.81 (95% CI: 0.76-0.86) and 0.70 (95% CI: 0.63-0.77) in the training and testing sets, respectively. CONCLUSION: We identified and verified a nine-gene signature for the prognostic prediction of IGC patients, which might identify subgroups of IGC patients and select more suitable therapeutic options.

Electrospun Fibrous Membrane Containing a Cyclodextrin Covalent Organic Framework with Antibacterial Properties for Accelerating Wound Healing.

Skin wounds are usually accompanied by bacterial infections and inflammations, leading to delayed wound healing, which remain a great challenge in clinical treatment. Therefore, it is of great significance to develop wound dressings that inhibit bacterial infections to accelerate wound healing. Herein, we reported the fabrication of inclusion complex (a ß-cyclodextrin covalent organic framework loaded with enrofloxacin and flunixin meglumine)-incorporated electrospun thermoplastic polyurethane fibers (named ENR-FM-COF-TPU) via electrospinning. The obtained ENR-FM-COF-TPU fibrous membrane exhibited excellent physicochemical and biological properties such as uniform and stable morphology, proper hydrophobicity, good water uptake capacity, and admirable biocompatibility, which showed perfect behavior as a wound dressing. In addition, the ENR-FM-COF-TPU membrane achieved a sustained drug release of enrofloxacin and flunixin meglumine and displayed powerful antibacterial activity against Staphylococcus aureus and Escherichia coli with 99% inhibitory efficiency for 50 h. More importantly, the wound healing therapy effect was investigated using a full-thickness skin defect model of mice. It suggested that the ENR-FM-COF-TPU membrane could significantly accelerate and enhance wound healing through downregulating inflammatory cytokines (IL-1ß and TNF-α) and increasing the expression of growth factors (VEGF and EGF). Due to its excellent properties, the ENR-FM-COF-TPU membrane may have promising potential in wound healing applications.

Cyclodextrin metal-organic framework as vaccine adjuvants enhances immune responses.

It is urgently needed to develop novel adjuvants for improving the safety and efficacy of vaccines. Metal-organic frameworks (MOFs), with high surface area, play an important role in drug delivery. With perfect biocompatibility and green preparation process, the γ-cyclodextrin metal-organic framework (γ-CD-MOF) fabricated with cyclodextrin and potassium suitable for antigen delivery. In this study, we modified γ-CD-MOF with span-85 to fabricate the SP-γ-CD-MOF as animal vaccine adjuvants. The ovalbumin (OVA) as the model antigen was encapsulated into particles to investigate the immune response. SP-γ-CD-MOF displayed excellent biocompatibility in vitro and in vivo. After immunization, SP-γ-CD-MOF loaded with OVA could induce high antigen-specific IgG titers and cytokine secretion. Meanwhile, SP-γ-CD-MOF also significantly improved the proliferation of spleen cells and activated and matured the bone marrow dendritic cells (BMDCs). The study showed the potential of SP-γ-CD-MOF in vaccine adjuvants and provided a novel idea for the development of vaccine adjuvants.

Enrofloxacin/florfenicol loaded cyclodextrin metal-organic-framework for drug delivery and controlled release.

We presented an antibiotic-loaded γ-cyclodextrin metal-organic framework that delivered antibiotics suitable for the treatment of bacterial infections. The γ-cyclodextrin metal-organic framework was developed using γ-cyclodextrin and potassium ion via the ultrasonic method. The antibiotic (florfenicol and enrofloxacin) was primarily encapsulated into the pore structures of γ-CD-MOF, which allowed the sustained release of antibiotics over an extended period of time in vitro and in vivo. Notably, antibiotics-loaded γ-CD-MOF showed much superior activity against bacteria than free antibiotics (lower MIC value) and displayed better long-lasting activity (longer antibacterial time). The antibiotics-loaded γ-CD-MOF showed nontoxic and perfect biocompatibility to mammalian cells and tissues both in vitro and in vivo. These materials thus represent a novel drug-delivery device suitable for antibiotic therapy. This research is of great significance for reducing the generation of bacterial resistance and providing new ideas for the application of γ-CD-MOF.

Upregulation of family with sequence similarity 83 member D expression enhances cell proliferation and motility via activation of Wnt/ß-catenin signaling and predicts poor prognosis in gastric cancer.

BACKGROUND/AIMS: Gastric cancer (GC) is the third most common cause of cancer-related death worldwide. The molecular mechanisms underlying the progression of gastric cancer are still not fully elucidated. In this study, we focused on exploring the role of family with sequence similarity 83, member D (FAM83D) in gastric cancer progression. METHODS: The expression of FAM83D in GC tissues was detected by immunohistochemistry (IHC) staining. FAM83D knockdown or overexpression were constructed in AGS and SGC-7901 cells with two distinct siRNA duplexes and lentivirus infection, respectively, to explore the role of FAM83D in gastric cancer progression. Nude mouse xenograft assay was used to further explore the role of FAM83D in tumorigenesis in vivo. RESULTS: We found that FAM83D mRNA and protein levels were higher in human GC tumor tissues and in GC cell lines, compared with the adjacent normal tissues and non-malignant gastric epithelial cell lines, respectively, and that higher FAM83D expression was correlated with worse overall survival (p<0.0001) and disease-free survival (p<0.0001) in GC patients. Additionally, our results showed that FAM83D overexpression significantly enhanced the proliferation, clonogenicity, and motility of GC cells, whereas FAM83D depletion caused a dramatic increase in the number of cells arrested at the G1 phase of the cell cycle. Consistent with these findings from in vitro experiment, our data also indicated that FAM83D knockdown significantly repressed GC tumor growth in vivo. Furthermore, we demonstrated that FAM83D depletion was associated with reduced Wnt/ß-catenin signaling. CONCLUSIONS: This study suggested that FAM83D overexpression enhanced the proliferation, clonogenicity, and motility of GC cells by activating Wnt/ß-catenin signaling, and FAM83D may be a promising diagnostic and therapeutic target for human GC.

LDLRAD2 overexpression predicts poor prognosis and promotes metastasis by activating Wnt/ß-catenin/EMT signaling cascade in gastric cancer.

The therapeutic strategies for advanced gastric cancer (GC) remain unsatisfying and limited. Therefore, it is still imperative to fully elucidate the mechanisms underlying GC aggressive progression. The prognostic value and biological functions of low density lipoprotein receptor class A domain containing protein 2 (LDLRAD2) in GC have never been studied yet. We found that LDLRAD2 expression was significantly upregulated in GC and closely correlated with poor prognosis in GC patients. Functionally, LDLRAD2 promoted epithelial-mesenchymal transition, migration and invasion, and metastasis of GC cells. Mechanistically, LDLRAD2 interacted with and inhibited Axin1 from binding to cytoplasmic ß-catenin, which facilitated the nuclear translocation of ß-catenin, thereby activating Wnt/ß-catenin pathway. Inhibition of ß-catenin activity markedly abolished LDLRAD2-induced migration, invasion and metastasis. Together, these results suggested that LDLRAD2 contributed to invasion and metastasis of GC through activating Wnt/ß-catenin pathway. LDLRAD2/ Wnt/ß-catenin axis may be a potential therapeutic target for GC treatment.

Differential Expression and Significance of Endoplasmic Reticulum Golgi Intermediate Compartment 1 in Precancerous Gastric Lesions and Gastric Cancer.

BACKGROUND: We investigated the expression of endoplasmic reticulum Golgi intermediate compartment 1 (ERGIC1) in precancerous gastric lesions and gastric cancer and the function of ERGIC in human gastric cancer cell lines. MATERIALS AND METHODS: A total of 160 subjects were enrolled. The expression of ERGIC1 was assayed using immunohistochemistry. Overexpression of ERGIC1 in SGC-7901 and BGC-823 cells was used to evaluate the function of ERGIC1. RESULTS: Most normal gastric mucosal tissues and the tissues with mild dysplasia showed strong expression of ERGIC1 (80% and 73.3%, respectively) assayed using immunohistochemistry. In the majority of gastric tissues with moderate and severe dysplasia, ERGIC1 was moderately positive (83.3% and 66.7%, respectively), whereas in a small proportion of gastric tissues with severe dysplasia (16.7%) and of the gastric cancer tissues (22.5%), ERGIC1 was weakly positive. No expression of ERGIC1 was found in the gastric tissues of a small proportion of severe dysplasia (16.7%) and in the most of the gastric cancer (67.5%) patients. Semiquantitative analysis revealed a gradual reduction in the expression score of ERGIC1 from normal gastric mucosal tissues to tissues from early gastric cancer. In addition, overexpression of ERGIC1 in SGC-7901 and BGC-823 cells inhibited the cell proliferation by 27.5% and 30%, respectively, on day 5. On the other hand, overexpression of ERGIC1 in both cell lines enhanced the apoptosis by 33.5% and 53.2%, respectively, as compared to control cells. CONCLUSION: These results suggested that ERGIC1 might play an inhibitory role in the initiation and progression of gastric cancer.

Tumor-derived exosomes induce PD1+ macrophage population in human gastric cancer that promotes disease progression.

Macrophages constitute a major component of tumor-infiltrating immune cells. M2 macrophages have been reported to promote tumor progression through promoting tumor angiogenesis and metastasis and regulating T-cell function. Here, we identified a protumorigenic subset of macrophages that constitutively expressed programmed cell death 1 (PD1) and accumulated in advanced-stage gastric cancer (GC). These PD1+ tumor-associated macrophages (TAMs) exhibited an M2-like surface profile, with a significant increase in the expression of CD206, IL-10, and CCL1, and a clear decrease in the expression of MHC class II, CD64, and IL-12 and the ability to phagocytose ovalbumin. Moreover, PD1+ TAMs can suppress CD8+ T-cell function and this immunosuppressive activity can effectively be enhanced upon triggering PD1 signal. GC-derived exosomes effectively educated monocytes to differentiate into PD1+ TAMs with M2 phenotypic and functional characteristics. Together, our results are the first to show that GC-derived exosomes can effectively induce PD1+ TAM generation, and these cells can produce a large number of IL-10, impair CD8+ T-cell function, and thereby create conditions that promote GC progression. Thus, methods in which immunotherapy is combined with targeting PD1+ TAMs and tumor-derived exosomes should be used to restore immune function in GC patients.

Aberrant DNA-PKcs and ERGIC1 expression may be involved in initiation of gastric cancer.

AIM: To investigate the molecular mechanisms of gastric carcinogenesis. METHODS: We used label-free quantification technology integrated with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis to identify differentially expressed proteins in 160 specimens of normal gastric mucosa, gastric mucosa with mild dysplasia, moderate dysplasia, severe dysplasia, and early mucosal gastric cancer (GC) collected at the Second Hospital of Lanzhou University from 2010 to 2015. Immunohistochemistry was used to verify the differentially expressed proteins detected by LC-MS/MS. RESULTS: With a threshold of a 1.2-fold change and a P-value < 0.05 between mild dysplasia, moderate dysplasia, severe dysplasia or early mucosal GC and matched normal gastric mucosa tissues, proteomic analysis identified 365 significantly differentially expressed proteins. ERGIC1 expression decreased, while DNA-PKcs expression increased gradually along with different stages of GC initiation based on the tendency of fold change. The expression patterns of ERGIC1 and DNA-PKcs revealed by immunohistochemistry were consistent with the LC-MS/MS results. CONCLUSION: The results suggest that aberrant ERGIC1 and DNA-PKcs expression may be involved in GC initiation.

Benzo[a]pyrene promotes gastric cancer cell proliferation and metastasis likely through the Aryl hydrocarbon receptor and ERK-dependent induction of MMP9 and c-myc.

Gastric cancer (GC) is the fifth most common cancer worldwide and the third leading cause of global cancer-related death. Benzo[a]pyrene (BaP), a Group Ⅰ carcinogen categorized by the IARC, is a cumulative foodborne carcinogen and ubiquitous environmental pollutant with potent carcinogenic properties. However, the function and mechanism of BaP exposure on GC progression remains unclear. We investigated the role of BaP in human GC progression to identify potential mechanism underlining its carcinogenic activity. After exposure to various concentrations of BaP, human GC cells SGC-7901 and MNK-45 showed an increased capability of proliferation, migration and invasion. Further study indicated that BaP promotes the expression of matrix metalloproteinase-9 (MMP9) and c-myc at mRNA and protein level, and activates Aryl hydrocarbon receptor (AhR) and ERK pathway. Moreover, BaP-induced overexpression of MMP9 and c-myc were attenuated by the ERK inhibitor U0126 and AhR inhibitor resveratrol, respectively. These data suggest that BaP promotes proliferation and metastasis of GC cells through upregulation of MMP9 and c-myc expression, and this was likely mediated via the AhR and ERK signaling pathway.

Interactional role of microRNAs and bHLH-PAS proteins in cancer (Review).

MicroRNAs (miRNAs) are recognized as an emerging class of master regulators that regulate human gene expression at the post-transcriptional level and are involved in many normal and pathological cellular processes. Mammalian basic HLH (helix-loop-helix)-PER-ARNT-SIM (bHLH-PAS) proteins are heterodimeric transcriptional regulators that sense and respond to environmental signals (such as chemical pollutants) or to physiological signals (for instance hypoxia). In the normal state, bHLH-PAS proteins are responsible for multiple critical aspects of physiology to ensure the cell accurate homeostasis, but dysregulation of these proteins has been shown to contribute to carcinogenic events such as tumor initiation, promotion, and progression. Increasing epidemiological and experimental studies have shown that bHLH-PAS proteins regulate a panel of miRNAs, whereas some miRNAs also target bHLH-PAS proteins. The interaction between miRNAs and certain bHLH-PAS proteins [hypoxia-inducible factor (HIF) and aryl hydrocarbon receptor (AHR)] is relevant to many vital events associated with tumorigenesis. This review will summarize recent findings on the interesting and complicated underlying mechanisms that miRNAs interact with HIFs or AHR in tumors, hopefully to benefit the discovery of novel drug-interfering targets for cancer therapy.

Protective effects of hepatic stellate cells against cisplatin-induced apoptosis in human hepatoma G2 cells.

The effects of hepatic stellate cells (HSCs) on tumorigenicity of HCC have been previously reported. However, the detailed mechanisms responsible for these effects remain unclear. In this study, we investigated the effects of HSCs on cisplatin-induced apoptosis in human hepatoma HepG2 cell lines. HepG2 cells were treated with cisplatin alone or co-cultured with LX-2 cells 3 days before incubation with cisplatin. Cisplatin causes apoptosis in HepG2 cells and LX-2 cells protect HepG2 cells from death. The protection of LX-2 cells against cisplatin-induced cytotoxicity in HepG2 cells appeared to be related to the inhibition of apoptosis, as determined by cytotoxicity assay and nuclear staining analysis. p53 and Bax mRNA levels were elevated, and cell cycle arrest was produced after cisplatin treatment. LX-2 cells suppressed this elevation of p53 and Bax as well as the cell cycle arrest induced by cisplatin, when compared with those of the treated cells with cisplatin alone. The LX-2 cells pretreatment inhibited the cisplatin-induced apoptosis, which was related with the incomplete blockage in p53 activation. In summary, the results of our present study demonstrate that HSCs protect HepG2 cells against cisplatin-induced apoptosis and its protective effects occur via inhibiting the activation of p53, which is of critical importance for enhanced understanding of fundamental cancer biology.