The critical role for TAK1 in trichloroethylene-induced contact hypersensitivity in vivo and in CD4+ T cell function alteration by trichloroethylene and its metabolites in vitro.

Occupational exposure to trichloroethylene (TCE) has been associated with severe, generalized contact hypersensitivity (CHS) skin disorder, which is considered a delayed-type hypersensitivity reaction mediated by antigen-specific T cells. Transforming growth factor-ß activated kinase-1 (TAK1) is essential for regulating the development and effector function of T cells. We hypothesized that disrupting TAK1 activity might inhibit TCE-induced CHS response. In this study, a local lymph node assay was employed to build a CHS model induced by TCE combined with the inducible-TAK1 deletion system to study the effect of TAK1 on it. It was observed that TAK1 deficiency ameliorated the TCE-induced CHS response and was associated with defective T cell expansion and activation and IFN-γ production in vivo. Furthermore, we investigated the effects of TCE and its metabolites trichloroacetic acid (TCA) and dichloroacetic acid (DCA) on CD4+ T cell function and the effect of TAK1 on it in vitro. The results showed that TCE, TCA and DCA augmented the proliferation, activation and differentiation of CD4+ T cells through Jnk MAPK and NF-κB pathways. TAK1 deletion significantly attenuated these effects induced by TCE, TCA or DCA on CD4+ T cells. In conclusion, it is suggested that TAK1 plays a critical role both in TCE-induced CHS response in vivo and in TCE and its metabolite-induced CD4+ T cell activation in vitro. Local inhibition of TAK1 might offer a promising alternative feasible strategy for TCE-induced CHS.

Blue light filtered white light induces depression-like responses and temporary spatial learning deficits in rats.

OBJECTIVES: Ambient light has a vital impact on mood and cognitive functions. Blue light has been previously reported to play a salient role in the antidepressant effect via melanopsin. Whether blue light filtered white light (BFW) affects mood and cognitive functions remains unclear. The present study aimed to investigate whether BFW led to depression-like symptoms and cognitive deficits including spatial learning and memory abilities in rats, and whether they were associated with the light-responsive function in retinal explants. METHODS: Male Sprague-Dawley albino rats were randomly divided into 2 groups (n = 10) and treated with a white light-emitting diode (LED) light source and BFW light source, respectively, under a standard 12 : 12 h L/D condition over 30 days. The sucrose consumption test, forced swim test (FST) and the level of plasma corticosterone (CORT) were employed to evaluate depression-like symptoms in rats. Cognitive functions were assessed by the Morris water maze (MWM) test. A multi-electrode array (MEA) system was utilized to measure electro-retinogram (ERG) responses induced by white or BFW flashes. RESULTS: The effect of BFW over 30 days on depression-like responses in rats was indicated by decreased sucrose consumption in the sucrose consumption test, an increased immobility time in the FST and an elevated level of plasma CORT. BFW led to temporary spatial learning deficits in rats, which was evidenced by prolonged escape latency and swimming distances in the spatial navigation test. However, no changes were observed in the short memory ability of rats treated with BFW. The micro-ERG results showed a delayed implicit time and reduced amplitudes evoked by BFW flashes compared to the white flash group. CONCLUSIONS: BFW induces depression-like symptoms and temporary spatial learning deficits in rats, which might be closely related to the impairment of light-evoked output signals in the retina.

Effects of coal-fired PM2.5 on the expression levels of atherosclerosis-related proteins and the phosphorylation level of MAPK in ApoE-/- mice.

BACKGROUND: Air pollution increases the morbidity and mortality of cardiovascular disease (CVD). Atherosclerosis (AS) is the pathological basis of most CVD, and the progression of atherosclerosis and the increase of fragile plaque rupture are the mechanism basis of the relationship between atmospheric particulate pollution and CVD. The aim of the present study was to investigate the effects of coal-fired fine particulate matter (PM2.5) on the expression levels of atherosclerosis-related proteins (von Willebrand factor (vWF), Endothelin-1 (ET-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin, and to explore the role and mechanism of the progression of atherosclerosis induced by coal-fired PM2.5 via the mitogen-activated protein kinase (MAPK) signaling pathways. METHODS: Different concentrations of PM2.5 were given to apolipoprotein-E knockout (ApoE-/-) mice via intratracheal instillation for 8 weeks. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of vWF, ET-1 in serum of mice. Immunohistochemistry was used to observe the expression and distribution of ICAM-1 and E-selectin in the aorta of mice. Western blot was used to investigate the phosphoylation of proteins relevant to MAPK signaling pathways. RESULTS: Coal-fired PM2.5 exacerbated atherosclerosis induced by a high-fat diet. Fibrous cap formation, foam cells accumulation, and atherosclerotic lesions were observed in the aortas of PM2.5-treated mice. Coal-fired PM2.5 increased the protein levels of ET-1, ICAM-1, and E-selectin, but there was no significant difference in the vWF levels between the PM2.5-treatment mice and the HFD control mice. Coal-fired PM2.5 promoted the phosphorylation of p38, c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) in aortic tissues of mice. CONCLUSION: Coal-derived PM2.5 exacerbated the formation of atherosclerosis in mice, increased the expression levels of atherosclerosis-related proteins in mice serum, and promoted the phosphorylation of proteins relevant to MAPK signaling pathway. Thus, MAPK signaling pathway may play a role in the atherosclerosis pathogenesis induced by Coal-derived PM2.5.

The role of MAPK in the biphasic dose-response phenomenon induced by cadmium and mercury in HEK293 cells.

Some studies show that Cd(2+) and Hg(2+) may induce cell proliferation and apoptosis via biphasic dose-response relationship in human cells. However, mechanisms underlying this phenomenon are still in puzzle. In this study, we aim at detecting the biphasic effects of Cd(2+) and Hg(2+) on proliferation and apoptosis of human embryonic kidney 293 (HEK293) cells, analyzing the change of the mitogen-activated protein kinase (MAPK) pathways, and discussing the relationship between them. The results demonstrate that Cd(2+) and Hg(2+) can stimulate cell proliferation at lower concentrations (0.05 and 0.5 microM) but inhibit it at higher concentrations (50 and 500 microM). Apoptosis increases at higher concentrations (50 and 500 microM) of Cd(2+) and Hg(2+). While 0.5 microM Cd(2+) and Hg(2+) decrease the JNK phosphorylation, 50 microM Cd(2+) and Hg(2+) increase the JNK and P38 phosphorylation. When HEK293 cells are treated with 20 microM JNK inhibitor or 100 microM ERK1/2 inhibitor, the cell proliferation do not increase significantly at low concentrations (0.05 and 0.5 microM), but still decrease at high concentrations (50 and 500 microM). When HEK293 cells are treated with 20 microM P38 inhibitor, the tendency of cell proliferation is not affected. Data in our study suggests that activation of MAPK pathway may be involved in the biphasic effect induced by Cd(2+) and Hg(2+).

TAK1 knock-down in macrophage alleviate lung inflammation induced by black carbon and aged black carbon.

Black carbon (BC) can combine with organic matter and form secondary pollutants known as aged BC. BC and aged BC can cause respiratory system inflammation and induce lesions at relevant sites, but the underlying mechanism has remained unknown. To gain insight into the potential mechanisms, we focused on macrophages and transforming growth factor ß-activated kinase 1 (TAK1) which are a crucial factor in inflammation. Our research aims to determine the role of TAK1 in macrophages in pulmonary inflammation induced by particulate matter. In this study, BC and 1,4-naphthoquinone were mixed to model aged BC (1,4NQ-BC) in atmosphere. BC induced mice lung inflammation model, lung macrophage knock-down TAK1 animal model and primary macrophage knock-down TAK1 model were used to explore whether TAK1 in macrophage is a critical role in the process of inflammation. The results showed that the expressions of inflammatory cytokines (IL-1ß, IL-6, IL-33) mRNA were significantly increased and the phosphorylation of MAPK and NF-κB signaling pathway related proteins were enhanced in RAW 264.7 cell lines. In vivo studies revealed that the indicators of pulmonary inflammation (pathology, inflammatory cell numbers) and related cytokines (IL-1ß, IL-6, IL-33) mRNA expressions in CD11c-Map3k7-/- animals were significantly lower than wild-type animals after mice were instilled particles. In mice primary macrophages, the expressions of IL-6, IL-33 mRNA were inhibited after TAK1 gene was knock-down. These results unequivocally demonstrated that TAK1 plays a crucial role in BC induced lung inflammation in mice, and we can infer that BC and 1,4NQ-BC cause these inflammatory responses by stimulating pulmonary macrophages.

Pubertal chlorocholine chloride exposure inhibits testicular testosterone synthesis by down-regulating steroidogenic enzymes in adult rats.

Chlorocholine chloride (CCC) is widely used to regulate plant growth. Considerable attention has been focused on its reproductive and developmental toxicities. In order to investigate the effects of pubertal CCC exposure on testicular testosterone (T) synthesis, male SD rats were exposed to CCC by oral gavage at doses of 0, 75, 150 and 300 mg/kg bw/day from postnatal day 23 to 70. We observed that pubertal CCC exposure lowered the body weight and the mean Johnsen's score. The percentage of seminiferous tubules with deciduous spermatogenic cells was increased in the 75 and 150 mg/kg bw/day groups. In addition, pubertal CCC exposure reduced the testicular absolute weights in the 75 and 300 mg/kg bw/day groups as well as the sperm motility in epididymides in the 150 mg/kg bw/day group. A significant decrease of testicular T was observed while levels of hypothalamic gonadotropin-releasing-hormone (GnRH) and serum luteinizing hormone (LH) were increased. Protein levels of steroidogenic acute regulatory (StAR), cholesterol side-chain cleavage enzyme (P450scc) and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) were decreased. Taken together, these results indicate that pubertal CCC exposure in rats might decrease testicular T synthesis by suppressing the expression of steroidogenic enzymes, which partially lead to an impairment on spermatogenesis.

The skeletal developmental toxicity of chlormequat chloride and its underlying mechanisms.

Chlormequat Chloride (CCC), a widely used plant growth regulator, could decrease body weight in animals; however, the mechanism has not been well studied. This study was designed to evaluate the skeletal development toxicity of CCC on pubertal male Sprague-Dawley (SD) rats and to investigate whether CCC impacts the development of chondrocyte, osteoblast and osteoclast through growth hormone (GH) and insulin like growth factor 1 (IGF-I). Rats from 23 to 70 on postnatal days were exposed to CCC daily by gavage at doses of 0, 75, 150, and 300mg/kg bw/d. The results showed that the size of femurs and tibias, bone mineral density and biomechanical parameters were significantly decreased in the 300mg/kg bw/d group compared with the control group. The concentration of osteocalcin (OCN) and C-terminal telopeptide of type I collagen (CTX-I) in blood in the 150mg/kg bw/d group was also changed. The mRNA expression ratio of the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in 150 and 300mg/kg bw/d group was increased. Histological analysis of proximal and distal epiphyseal plates of the right femurs showed that both the proliferative zone and hypertrophic zone narrowed in CCC-treated groups. The concentration of IGF-I in blood was reduced with an increase in exposure doses of CCC. The mRNA expression of growth hormone receptor (GHR) in tibia was decreased in the CCC-treated group. The results indicated that CCC might indirectly impact the formation and activation of chondrocytes, osteoblasts and osteoclasts because of the decline of GHR and IGF-I, leading to skeletal development damage.

The effect of ethephon on immune system in male offspring of mice.

Ethephon can liberate ethylene which could interfere the plant growth process. The aim of the present study was to determine the effect of ethephon on developing immune system of male offspring. Ethephon could enhance NK cell activity in male mice. For 4-week-old male mice, lymphocytes of peripheral blood increased while the hemolytic plaque number decreased. Delayed type hypersensitivity(DTH) was inhibited in all groups. The expression of protein Bcl11b and p-p38 in thymus of treatment groups were lower than control group. Our results indicated that cellular immunity of male offspring is more sensitive to ethephon when exposed in pregnancy and lactation period. It should be emphasized that exposure to ethephon during the in utero stage and lactation stage still could damage the immune function of animal in the period before fully mature even in the dosage that could not influence the immune function of adult animal.

The research of genetic toxicity of ß-phellandrene.

ß-Phellandrene, a plant extract, can be used as natural pesticides and synthetic materials. As a factor that human may be exposed to, the toxicity information about ß-phellandrene is scared at present. This study focused on the genetic toxicity of ß-phellandrene. The genetic toxicity of ß-phellandrene was evaluated by micronucleus test, comet assay, Ames test, and chromosomal aberration test. In this study, 2850, 1425, 712.5mg/kg ß-phellandrene were used in vivo experiments (comet assay and micronucleus test). For Ames test, pure ß-phellandrene and different concentrations were used in the experiment. According to the results of cell viability assay (MTT test), the concentration of chromosomal aberration test was formulated. The result of comet assay showed that ß-phellandrene can significantly induce DNA damage at the dosage of 1425 and 2850mg/kg. While the results of Micronucleus test and chromosome aberration test showed that ß-phellandrene does not lead to apparently genetic toxicity on chromosome level. Ames tests suggest that ß-phellandrene had the ability to increase gene mutation with or without S9 mixture. So, it could be drawn that ß-phellandrene would have certain genetic toxicity, and the toxicity is reflected as DNA strand breaks and mutation. This study filled the lack of genetic toxicity study of ß-phellandrene, and enriched information for risk assessment for ß-phellandrene.

The effects of chlormequat chloride on the development of pubertal male rats.

Chlormequat Chloride (CCC) is a plant growth regulator that is widely applied in agriculture. Previous studies have shown that long-term exposure of CCC could decrease body weight in animals. However, the underlying mechanisms have not been studied. In this study, CCC was administered to rats daily by gavage on postnatal days 23-60 at doses of 0, 75, 150 and 300mg/kg bw/d. The results showed that body weight and the length of the right femur were significantly decreased in the 300mg/kg bw/d group. Histological analysis of proximal growth plates of the right femurs showed narrowed proliferative zones and hypertrophic zones in CCC-treated groups. The mRNA expression of growth hormone, growth hormone receptor and insulin like growth factor 1 were decreased in the CCC-treated group. The results indicated that CCC may affect the expression of growth hormone and insulin-like growth factor 1 and subsequently cause a decrease in body weight and bone length.

MAP4K4 deficiency in CD4(+) T cells aggravates lung damage induced by ozone-oxidized black carbon particles.

As the main composition of combustion, black carbon (BC) is becoming more and more noticeable at home and abroad. Ozone-oxidized black carbon (oBC) was produced through aging of ozone, one of the near-surface pollutants, to black carbon. And oBC was found to be more oxidation and cell toxicity when compared with BC. Besides, as a key cell of immunity, whether CD4(+) T cell would involve in lung inflammation induced by particular matter is still unclear. This study aims to observe the effect of oBC on lung damage in mice and discuss how the functional MAP4K4 defect CD4(+) T cells (conditional knockout of MAP4K4) presents its role in this process. In our study, MAP4K4 deletion in CD4(+) T cells (MAP4K4 cKO) could increase cell number of macrophages, lymphocytes and neutrophils in bronchoalveolar lavage fluid (BALF) exposed to oBC. MAP4K4 deletion in CD4(+) T cell also affected CD4(+) T cell differentiation in mediastinal lymph nodes after oBC stimulation. The number of CD4(+) IL17(+) T cell increased obviously. The levels of IL-6 mRNA of lung in MAP4K4 cKO mice was higher than that in wild type mice after exposed to oBC, while the level of IL-6 in BALF had the same trend. Histological examination showed that MAP4K4 deletion in CD4(+) T cells affected lung inflammation induced by oBC. Results indicated that MAP4K4 cKO in CD4(+) T cells upgraded the level of inflammation in lung when exposed to oBC, which may be connected to the CD4(+) T cell differentiation and JNK, ERK and P38 pathways.

Gene expression profiles of hepatocytes treated with La(NO3)3 of rare earth in rats.

AIM: To compare the gene expression between La(NO(3))(3)-exposed and control rats in vivo. METHODS: Rats were fed La(NO(3))(3) once daily at a dose of 20 mg/kg for one month by gavage. Gene expression of hepatocytes was detected using mRNA differential display (DD) technique and cDNA microarray and compared between treated and control groups. RESULTS: Six differentially expressed sequence tags were cloned by DD, of which five were up regulated and one was down regulated in treated rats. Two sequences were determined. One band was novel. The other shared 100% sequence homology with AU080263 Sugano mouse brain mncb Mus musculus cDNA clone MNCb-5435 5'. With DNA microarray, 136 differentially expressed genes were identified including 131 over-expressed genes and 5 under-expressed genes. Most of these differentially expressed genes were cell signal and transmission genes, genes associated with metabolism, protein translation and synthesis. CONCLUSION: La(NO(3))(3) could change the expression levels of some kinds of genes. Further analysis of the differentially expressed genes would be helpful for understanding the wide biological effect spectrum of rare earth elements.

[The induction of apoptosis and reactive oxygen species in human skin fibroblast by ultraviolet A].

OBJECTIVE: To analyse the induction of apoptosis and reactive oxygen species (ROS) in human skin fibroblast by ultraviolet A (UVA). METHODS: Human skin fibroblasts were irradiated with UVA, apoptosis was determined with flowcytometry and fluorescent microscopy, the intracellular ROS production was measured with a spectrofluorometer, and the free radicals were determined with electron spin resonance. RESULTS: A significant increase of apoptosis was observed in human skin fibroblast after exposure to UVA with a dosage at 110-120 kJ.m-2, mannitol could counteract apoptosis; a higher level of intracellular ROS and the hydroxyl free radical was detected in the irradiated samples. CONCLUSION: A lower dose of irradiation of UVA(0.6 mW.cm-2) can induce apoptosis in human skin fibroblast, and ROS might play a role in the induction of apoptosis.

[Effect of 7,12-dimethylbenz(a)athrancene on immune function in metallothionein gene-knocked-out mice].

OBJECTIVE: To study the immunotoxicity induced by 9,10-dimethyl-1,2-benzathrancene (DMBA) in metallothionein gene-knocked-out mice [MT(-/-)] as compared with that in wild-type mice [(MT(+/+)]. METHODS: Female mice were treated with 25 mg/kg and 50 mg/kg of DMBA i.p., respectively and immunized with sheep red blood cells (SRBC) i.v. on the following day and rechallenged by injection of SRBC via footpad s.c. on the fourth day post-immunization. Humoral and cell-mediated immune function was assessed by the number of spleen IgM antibody plaque formation cells (PFC) to SRBC and cell-mediated delayed-type hypersensitivity (DTH) measured by footpad swelling thickness. RESULTS: After treatment with 25 mg/kg DMBA, a decrease in weight of their spleen and thymus and PFC/spleen were observed in MT(-/-) mice, while only decrease in thymus weight of MT(+/+) mice. The humoral function was suppressed by 72% in MT(-/-) mice. No obvious change in cell-mediated immune function was observed both in MT(-/-) and MT(+/+) mice. Both humoral and cell-mediated immune function were suppressed more severe (91%) in MT(-/-) mice treated with 50 mg/kg DMBA than those treated with 25 mg/kg DMBA (72%). DTH was not altered by DMBA in MT(+/+) mice. The weight of their spleen and thymus decreased and humoral immune function suppressed in MT(+/+) mice, but these changes were significantly less severe. No obvious suppression of cell-mediated immune function was observed in MT(+/+) mice. CONCLUSION: Their humoral and cell-mediated immune function was more susceptible to being suppressed by DMBA in MT(-/-) mice, indicating that MT could protect their immune function from damage caused by DMBA.

Bisphenol A inhibits proliferation and induces apoptosis in micromass cultures of rat embryonic midbrain cells through the JNK, CREB and p53 signaling pathways.

Bisphenol A (BPA) has been widely used in the manufacture of polycarbonate plastic, water bottles and food containers. Previous studies have established that BPA could cause developmental toxicity by inhibiting the proliferation and differentiation of rat embryonic midbrain (MB) cells in vitro. However, the underlying mechanisms have not been well studied yet. In the current study, we examined the proliferation and differentiation of MB cells treated with 10(-12)-10(-4)M BPA and found that only 10(-4)M BPA inhibited proliferation and differentiation. Then, we investigated the cell cycle progression and apoptosis of MB cells; 10(-4)M BPA caused an explicit S phase and G2/M phase arrest in the cell cycle and increased the percentage of apoptotic cells. Moreover, the phosphorylation of mitogen-activated protein kinase (MAPK) and cyclic-AMP response binding protein (CREB) and the expression of some apoptotic regulatory genes were investigated. BPA (10(-4)M) reduced the phosphorylation of C-Jun N-terminal kinase (JNK) and CREB, and increased the mRNA expression level of Bax and p53. Our findings demonstrated that BPA could cause developmental toxicity through anti-proliferation and pro-apoptosis in MB cells. Multiple signaling pathways, such as the JNK, CREB and p53-mitochondrial apoptosis pathways, participate in these effects.

Individual and combined developmental toxicity assessment of bisphenol A and genistein using the embryonic stem cell test in vitro.

The potential developmental toxicity of environmental estrogenic endocrine disruptors have become a great concern in recent years. In this study, two typical environmental oestrogen, namely, bisphenol A (BPA) and genistein (GEN) were investigated for potential embryotoxicity using the embryonic stem cell test model. Afterwards, a 4×4 full factorial design and the estimated marginal means plot were performed to assess the combined effects of these two compounds. According to the linear discriminant functions and classification criteria, bisphenol A and genistein were classified as weakly embryotoxic and strongly embryotoxic respectively. As for combined effects, the overall interaction between BPA and GEN on embryonic stem cells (ESCs) differentiation was synergistic at low dosages, however, on ESCs and 3T3 cell proliferation, the predominate action was additive. Considering the actual daily intake of these chemicals, it is concluded that BPA alone might not have adverse reproductive or developmental effects on human being. However, given that BPA and GEN do have synergistic effect at low concentration, they may disturb normal embryo development together, which could result in birth defect and behavioral alterations later in life.

Effects of bisphenol A on the proliferation and cell cycle of HBL-100 cells.

Bisphenol A (BPA) is an environmental estrogen that exhibits non-genotoxic carcinogenicity, causing concern globally. The aim was to investigate the effects of BPA on the proliferation and cell cycle of human normal breast cells HBL-100. An improved E-Screen assay was used to study cell proliferation, and flow cytometry was used to study cell cycle phases. Western blot analysis was utilized to detect cell cycle proteins and estrogen receptor α (ERα) expression. The results showed that the highest cell proliferation rate induced by BPA was at 1.0 × 10(-6)mol/L. At 1.0 × 10(-10), 1.0 × 10(-8), and 1.0 × 10(-6)mol/L, BPA promoted more cells to enter into G2/M phase and caused an increase in the expression of cyclinD1 and CDK4. After adding ICI182780 into the system, the promoting effects of BPA on cell proliferation and cell cycle change decreased, but these promoting effects were still significantly greater compared with the solvent control (P<0.05). Regardless of ICI182780 exposure, BPA did not have significant effect on ERα expression. BPA has estrogen-like activity and can stimulate HBL-100 proliferation and cell division through the estrogen receptor pathway. BPA may have other pathways through which it can exert stimulating effects and exhibit non-genotoxic carcinogenicity.

Grape-seed proanthocyanidins ameliorate contact hypersensitivity induced by 2,4-dinitrofluorobenzene (DNFB) and inhibit T cell proliferation in vitro.

Contact hypersensitivity (CHS) is a delayed-type hypersensitivity reaction which is mediated by hapten-specific T cells. Strong haptens, such as 2, 4-dinitrofluorobenzene (DNFB) can induce it. Grape seed proanthocyanidins extract (GSPs), which is an antioxidant derived from grape seeds, has been reported to possess a variety of potent properties. However, few reports demonstrated the effects of GSPs on contact hypersensitivity. Therefore, the present study was devised to describe the role of GSPs on a mouse model of experimental CHS induced by DNFB and try to explore the possible underlying mechanisms. We observed that, GSPs when orally administrated into the CHS mice, inhibited the aggravation of inflammation. After administration of GSPs, there was obvious fewer inflammatory cell infiltration in the inflamed ears. Ear swelling after challenge was significantly reduced. In addition, we investigated the effects of GSPs on T cells in vitro, which play critical role during the progress of CHS. It was found that GSPs inhibited proliferative activity of T cells by blocking the activation of mitogen-activated protein kinases (MAPK) and NF-кB signaling pathways. Collectively, these results showed that GSPs has protective effect on CHS induced by DNFB and it also could inhibit the proliferation ability of T cells in vitro, suggesting the potential of GSPs as new and effective compound for the treatment of T-cell mediated inflammatory diseases.

In vitro malignant transformation of human bronchial epithelial cells induced by benzo(a)pyrene.

In this study, the human bronchial epithelial cells (16HBE) were treated five times with 10µM benzo(a)pyrene (BaP), followed by 20 passages culture, and the in vitro BaP-induced malignant transformation of 16HBE cells was established. Five colonies in soft agarose were then amplified and donated as T-16HBE-C1∼5 cells, respectively. T-16HBE-C1∼5 cells can form tumors subcutaneously in nude mice. Histopathological changes in the tumors indicated nests growth, high nuclear-cytoplasmic ratios, coarse and clumped chromatin, numerous and distinctly atypical mitoses, cell necrosis and surrounding normal adipose, muscle and connective tissue immersed. In addition, lung metastasis was observed in nude mice in T-16HBE-C1, 3 and 4 groups. In vitro cell migration assay results indicated that T-16HBE-C2∼5 cells showed much lower migration capabilities than 16HBE cells. Western blotting analysis showed that the expressions of p53 and p-Akt (Ser473) in T-16HBE-C1∼5 cells were significant higher than those in 16HBE cells. Our results demonstrated that BaP could induce the malignant transformation of 16HBE cells, and p53 and p-Akt (Ser473) might play crucial roles in BaP-induced carcinogenesis. The five monoclonal cell lines (T-16HBE-C1∼5) with different migration capabilities could be used as research models for further understanding the mechanisms of BaP-induced carcinogenesis and cell migration.