Macrophage AHR-TLR4 cross-talk drives p-STAT3 (Ser727)-mediated mitochondrial oxidative stress and upregulates IDO/ICAM-1 in the steatohepatitis induced by aflatoxin B1

Aflatoxin B1 (AFB1) is a major mycotoxin contaminant showing in the environment and foods. In this study, the molecular initiating events (MIEs) of AFB1-induced steatohepatitis were explored in mice and human cell model. We observed dose-dependent steatohepatitis in the AFB1-treated mice, including triglyceride accumulation, fibrotic collagen secretion, enrichment of CD11b + and F4/80+ macrophages/Kupffer cells, cell death, lymphocytes clusters and remarkable atrophy areas. The gut barrier and gut-microbiota were also severely damaged after the AFB1 treatment and pre-conditioned colitis in the experimental mice aggravated the steatohepatitis phenotypes. We found that macrophages cells can be pro-inflammatorily activated to M1-like phenotype by AFB1 through an AHR/TLR4/p-STAT3 (Ser727)-mediated mitochondrial oxidative stress. The phenotypes can be rescued by AHR inhibitors in the mice model and human cell model. We further showed that this signaling axis is based on the cross-talk interaction between AHR and TLR4. Gene knock-up experiment found that the signaling is dependent on AFB1 ligand-binding with AHR, but not protein expressions of TLR4. The signaling elevated NLRP3 and two immune metabolic enzymes ICAM-1 and IDO that are associated with macrophage polarization. Results from intervention experiments with natural anti-oxidant and AHR inhibitor CH223191 suggest that the macrophage polarization may rely on AHR and ROS. Our study provides novel and critical references to the food safety and public health regulation of AFB1.

Abstract P3-10-13: Bilateral breast cancer in China: A 10-year single-center retrospective study

BACKGROUD: Women with unilateral breast cancer are at increased risk for developing contralateral disease. The objective of the single-center retrospective study was to evaluate the incidence of bilateral breast cancer (BBC) and to analyze the clinicopathological characteristics for BBC in China.

METHODS: We retrospectively reviewed the electronic medical records of 3924 female patients with breast cancer consecutively treated at the department of Breast Oncology in the Peking University Cancer Hospital between 2006 and 2016. BBC was categorized as synchronous (within 6 months) or metachronous bilateral breast cancer (after 6 months of a first tumor). Patients with BBC were identified according to the criteria described by Chaudary et al. Patients with stage IV first breast cancer, and those who were found to have distant metastases between the first and second primary breast cancer were excluded. Analyses of demographic, clinicopathologic, and treatment characteristics were done between sBBC and mBBC.

RESULTS: The incidence of BBC in our population was 3.2% (127 of 3924). Of those, 2.5 % ( 99 of 3924) were metachronous bilateral breast cancer ( mBBC ), and 0.71 % (28 of 3924) were synchronous bilateral breast cancer ( sBBC ). The overall median age of the patients at first diagnosis was 45 years (range, 27-81 years). The age of onset of the first mBBC was significantly younger than that of sBBC ( p = 0.027). In mBBC subgroups, the median time interval between first and second tumors was 68 months (range, 7-342 months), and 80.8% of the second tumor were diagnosed within 10 years of the diagnosis of the first tumor. A positive family history of breast cancer was found in 25% of sBBC and 9.1% of mBBC ( p = 0.025). In ER-negative first tumor of mBBC, 56.1% of the second tumor were ER-positive. Mastectomy was the commonest surgery performed in these patients.

CONCLUSIONS: Our results confirmed the necessity of screening contralateral breast at the diagnosis of unilateral breast cancer and following-up for Chinese patients with breast cancer.

Citation Format: Li H, Jiang H, Zhang R, Shao B, Yan Y, Ran R, Di L. Bilateral breast cancer in China: A 10-year single-center retrospective study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-13.

Abstract P2-02-06: Biomarker analysis by next generation circulating tumor DNA (ctDNA) sequencing in patients with advanced breast cancer

Background: Next-generation sequencing is of increasing interest to identify specific targets for both drug development and treatment. The study of metastatic cancer is complicated by lack of tissue and the potential for change in biology over treatment. We evaluated ctDNA in patients with advanced breast cancer to explore the relationship between specific DNA mutations and prognosis as well as therapeutic decision making.

Methods:Peripheral blood was collected in EDTA at the time of diagnosis of advanced disease. Samples were sent to Geneplus-Beijing for sequencing. Indexed Illumina libraries were prepared from germline and circulating DNA using the KAPA Library Preparation Kit; the capture probe was designed based on genomic regions selected with 1021 genes, covering the most frequently mutated genes and exons in solid tumors. Clinical characteristics, treatment and outcome data were collected. We analyzed progression free survival (PFS) from first-line therapy and overall survival (OS), endpoints were correlated with observed gene mutations.

Results: 54 patients were enrolled; 27 (50%) HER2+, 22 (41%) hormone receptor + (HR+)/HER2-, and 5 (9%) triple negative (TNBC). Median age was 48 (range 26-74). The median follow-up was 8 years (range 12-180 months). First-line therapy included chemotherapy with trastuzumab for HER2+ disease, chemotherapy with endocrine maintenance (17) or endocrine therapy alone (5) for HR+/HER2- disease, and chemotherapy for TNBC. Mutations were found in TP53, PIK3CA, PIK3CA 3140 A>G(p.H1047R) and ERBB (including ERBB1-4), at 40.7%, 35.2%, 20.4% and 25.9%, respectively. In univariate analysis, patients with tumor mutations in TP53 had a shorter OS (median 64 vs 121 months, p=0.006). The PIK3CA 3140 A>G mutation was more frequent in HER2+ (7/27, 25.9%) than HR+/HER2- (4/22 (18.2%) or TNBC (0/5), and was associated with shorter median PFS in HER2+ disease (mutant vs. wild type: 4 (range 2-9) vs. 8 (range 2-22) months, p=0.006). The frequency of ERBB mutation was similar in HER2- 7/27(25.9%) (p=0.707) or HER2+ 7/27(25.9%) disease (p=0.066); there was no significant impact on PFS in any subset. Multivariate analysis for HER2+ disease including age, ER, Ki67, TP53, PIK3CA, PIK3CA 3140 A>G and ERBB), demonstrated that the PIK3CA 3140 A>G mutation was the only factor associated with shorter PFS (p=0.025); further analysis by receiver operating characteristic (ROC) curve showed that the PIK3CA 3140 A>G mutation and the mutation in PIK3CA 3140 A>G and ERBB combination pathway had a large area under the curve (AUC), with AUC of 0.789, and 0.734 respectively.

Conclusions: Using NGS in ctDNA, we found that the PIK3CA 3140A>G mutation was more frequent in HER2+ disease, and was the only mutation associated with shorter PFS on multivariate analysis. The presence of a TP53 mutation was associated with worse OS. Evaluation of ctDNA is feasible in a general breast cancer population and has prognostic impact; further correlation of these findings with tumor samples is ongoing.

Citation Format: Li H, Wang J, Rugo HS, Zhang Y, Yang L, Liu X, Shao B, Xu Y, Yang L, Zhang R, Ran R, Chang L. Biomarker analysis by next generation circulating tumor DNA (ctDNA) sequencing in patients with advanced breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-06.

The metabolic responses of HepG2 cells to the exposure of mycotoxin deoxynivalenol

As the number of reported deoxynivalenol (DON) contamination incidents increased steadily over the past decades, there has been a widespread interest in understanding the cellular mechanisms of the toxicological effects of DON using in vitro systems and omics technologies. The present investigation was conducted to understand the metabolomic changes in human hepatocellular carcinoma cells (HepG2) exposed to 10 μM DON for short term (4 h) and long term (12 h) periods, using a non-targeted metabolomics approach. Our results revealed a remarkable metabolic shift from short term to long term exposure to DON in HepG2 cells. Our metabolomics data also confirmed the role of DON induced oxidative stress in DON toxicity. Coupled with pattern recognition and pathway analysis, effects of DON on redox homeostasis, energy balance, lipid metabolism, and potential toxicological mechanisms were discussed, which would facilitate further studies on the risk assessment of the dietary mycotoxin DON.

Enhanced tumor accumulation and cellular uptake of liposomes modified with ether-bond linked cholesterol derivatives

Novel liposomal formulations based on cholesterol modification had been designed previously by our lab, but we found them with a poor stability and short half-life, especially in blood circulation. The results might be attributed to the hydrolysis of ester linked cholesterol derivatives by esterase in plasma. Thus, in this study, we newly synthesized ether-linked cholesterol derivatives and compared them to other preparations. A comparison with the substrate cholesterol-PEG2000-maleimide showed that ether-linked cholesterol-PEG2000-maleimide could relatively maintain integrity in serum, with only a small mottle emerging on TLC (thin-layer chromatography) plates through the experiment. Then a cell-penetrating peptide TAT was attached to the distal end of CHO-PEG2000 to prepare liposomes and to further evaluate the two cholesterol derivatives. Optimized liposomes (65:35, lipid/cholesterol, molar ratio) composed of 3% CHO-PEG2000 and 3% CHO-PEG2000-TAT showed good stability in 50%FBS (fetal bovine serum). In vitro experiments showed that as incubation time prolonged, ether-linked-TAT LIP showed a 3.67-fold higher uptake amount than ester-linked-TAT LIP. In vivo, ether-linked-TAT LIP accumulated better in tumors and had a 40% higher cellular uptake amount. Altogether, we could conclude that our newly ether-linked cholesterol derivatives possessed better stability especially in blood circulation which led to increased tumor cellular uptake in vitro and in vivo. Our study may offer a better way in cholesterol modification to prepare functionalized liposomes.

[Effect of exogenous p16 gene on the growth of wild-type p53 human lung adenocarcinoma cells]

OBJECTIVE

To study the effect of p16 gene on human adenocarcinoma cell lines and the posibility of exogenous p16 gene for gene therapy of lung cancer.

METHODS

A p16 gene recombinant expression vector was constructed by cloning p16 cDNA into the pcDNA3 vector at the sites of BamH1 and Xho I, and was transferred by electroporation into p16 gene deficient human lung adenocarcinoma cell lines (A549 and H460) which expressed wild-type p53 gene. The p16 mRNA and protein expression of A549-p16 and H460-p16 cell was detected by Northern blots and immunocytochemistry, respectively. The cell growth properties and cell cycle pattern were aassessed by flow cytometry.

RESULTS

The growth and colony forming efficiency of A549-p16 and H460-p16 cells were significantly inhibited compared with the controls. Flow cytometry showed A549-p16 and H460-p16 cells were arrested in G1 phase of cell cycle, and the percentage of cells in S phase and G2/M phase was decreased significantly. Tumorigenicity of the A549-p16 and H460-p16 cells in nude mice was greatly inhibited.

CONCLUSION

The results show that human p16 gene can suppress the malignant phenotype of wild-type p53 human lung adenocarcinoma cell lines (A549 and H460). p16 gene can play a role in the gene therapy of human lung adenocarcinoma.

[Development and application of the method for controlling contamination of tumor samples with normal cells to detect deletion of P16 gene in primary lung carcinoma]

OBJECTIVE

The method is to be established to effectively promote the sensitivity of the detection of P16 gene deletion from tumor tissues mixed with normal cells and to determine the relationship between the gene alteration and the lung cancers.

METHODS

The normal DNA and that of MCF-7 cells with P16 gene deletion was proportionally mixed and the mixture was limitedly diluted. The exon2 of P16 gene and internal control gene fragment were amplified with template of various amounts of DNA. And polymerase chain reaction (PCR) technique was used in the amplification of exon2 of P16 gene with certain amount of lung cancer DNA as the templates. The amplified fragment was analyzed with SSCP.

RESULTS

Normal DNA did not contaminate P16 gene deletion when DNA template was 5 ng and normal cells less than 40%. No deletion and mutation of P16 gene was found in the small cell lung cancer and normal cancer-surrounding lung tissues, while P16 gene deletion and mutation were found respectively in 21 and 3 cases of 52 cases of non-small cell lung cancer. The rate of P16 gene deletion (72%) in lung cancer with lymphatic involvement was significantly higher than that in lung cancer without the metastasis (16.8%) (P < 0.05). It is found that P16 gene deletion was markedly associated with pathologic manifestation and prognosis of non-small cell lung cancer (P < 0.05).

CONCLUSIONS

Controlling of the amount of template DNA in PCR helps to promote the sensitivity of detection of P16 gene deletion. The abnormality of P16 gene might relate to the malignant development of non-small cell lung cancer.

[Study on tumor necrosis factor receptor of human gastric cancer cells]

OBJECTIVE

To explore the relationship between the number of tumor necrosis factor receptors (TNFR) and the degree of differentiation of gastric cancer cells, and the relationship between the number of TNFR and the cytotoxicity of tumor necrosis factor mutant (TNF-m).

METHODS

With 125I-TNF-m, the radio-ligand binding assay was used to detect the TNFR on three gastric cancer cell lines (MKN28, SGC7901 MKN45) with from high to low degrees of differentiation. MTT colorimetric method was used to study the cytotoxicity of TNF-m on the three gastric cancer cell lines in vitro.

RESULTS

The number of TNFR of the three gestric cancer cells was 9.8 x 10(-12) nmol, 5.6 x 10(-12) nmol and 3.2 x 10(-12) nmol per cell respectively it differed significent from each other (P < 0.05) but the dissociation constant was basically the same. The rate of TNF-m internalization of the three gastric cancer cells was nearly the same and temperature dependent. The half-life of TNFR was about 90 mins. The ratio of membrane receptors to cytoplasm receptors was about 0.5. The maximum killing rate of TNF-m was 86%, 60% and 34% for MKN28, SGC7901, MKN45 cells, respectively, which were significantly different (P < 0.05). Killing rate of TNF-m to these cells at 39 degrees C was higher than at 37 degrees C.

CONCLUSIONS

The number of TNFR on the surface of gastric cancer cells was associated with the degree of differentiation of gastric cancer cells. The cytotoxicity of TNF-m was related to the number of TNFR and the rate of internalization of TNF-m.

[Rhubarb decoction prevents intestinal bacterial translocation during necrotic pancreatitis]

This is a study on the efficacy and mechanism of rhubarb therapy for necrotizing pancreatitis in rats induce by intraductal infusion of 2% deoxycholate 0.4 ml/kg. The rats with such pancreatitis were orally fed with 10% rhubarb decoction 1.5 ml (treatment group n = 8) or normal saline 1.5 ml (control group n = 9) per 8 hours. Sham operated rats (sham group n = 8) were given intraductal infusion of normal saline 0.4 ml/kg. 48 hours after infusion, the rats were killed for studies of intestinal motility, serum endotoxin and amylase levels as well as bacterial cultures in messentary lymph nodes (MLN) and pancreas tissues. 5 rats died in the control group (5/9) and 1 died in the treatment group (1/8). Remarkable inhibition of gut motility was observed in control group, but gut motility was significantly improved by administration of rhubarb in treatment group. No rat died in the sham group and the rate therein were all free from endotoxemia or positive cultures. Endotoxin level of control group is much higher (61.36 +/- 28.30 pg/L) than that of treatment group (5.41 +/- 3.58 pg/L), (P < 0.001). Positive cultures were noted in most of MLN (4/4) and pancreas (4/4) in control group, but only 1 in MLN and 1 in pancreas were noted in treatment group. It is concluded that in the treatment of necrotic pancreatitis in rats rhubarb decoction is effective for promoting gut motility and preventing intestinal bacterial translocation.

[Experimental study on intratumoral injection with hydroxyapatite bioceramics and adriamycin in implanted hepatoma in mice]

Hydroxyapatite (HA) bioceramics is a biomaterial used in orthopedic area. We observed its anticancer effect in experimental hepatoma-22 (H22) in mice. BALB/c mice implanted with H22 were grouped into I, II, III and IV. Intratumoral injections were given as follows: (I) HA 0.1 g and ADM 0.1 mg n = 28; (II) HA 0.1 g n = 16; (III) ADM 0.1 mg n = 16; (IV) untreated n = 20. The tumor regression rates of the groups I, II and III were 65.9%, 41.9% and 51.1%, respectively. The mean survivals of groups I, II, III and IV were 32, 22, 26 and 18 days. Six mice of group I were alive more than 50 days before being killed, in which 4 tumor samples showed that no residual tumor cells could be seen under microscope. The possible mechanism of HA anti-cancer action is: (1) the dissolved matter of HA, glycoprotein and microfibril around the tumor cells may disturb the metabolism of cancer; (2) fibrocalcific process restricts the tumor growth; (3) immunoenhancement action (4) as a drug-release system HA is a hopeful agent of intratumoral injection for treatment of cancer.