Epithelial cell adhesion molecule promotes breast cancer resistance protein-mediated multidrug resistance in breast cancer by inducing partial epithelial-mesenchymal transition.

Overexpression of breast cancer resistance protein (BCRP) plays a crucial role in the acquired multidrug resistance (MDR) in breast cancer. The elucidation of molecular events that confer BCRP-mediated MDR is of major therapeutic importance in breast cancer. Epithelial cell adhesion molecule (EpCAM) has been implicated in tumor progression and drug resistance in various types of cancers, including breast cancer. However, the role of EpCAM in BCRP-mediated MDR in breast cancer remains unknown. In the present study, we revealed that EpCAM expression was upregulated in BCRP-overexpressing breast cancer MCF-7/MX cells, and EpCAM knockdown using siRNA reduced BCRP expression and increased the sensitivity of MCF-7/MX cells to mitoxantrone (MX). The epithelial-mesenchymal transition (EMT) promoted BCRP-mediated MDR in breast cancer cells, and EpCAM knockdown partially suppressed EMT progression in MCF-7/MX cells. In addition, Wnt/ß-catenin signaling was activated in MCF-7/MX cells, and the inhibition of this signaling attenuated EpCAM and BCRP expression and partially reversed EMT. Together, this study illustrates that EpCAM upregulation by Wnt/ß-catenin signaling induces partial EMT to promote BCRP-mediated MDR resistance in breast cancer cells. EpCAM may be a potential therapeutic target for overcoming BCRP-mediated resistance in human breast cancer.

[The surface biomarkers of sputum cells in coal mine workers and patients with pneumoconiosis].

OBJECTIVE: To explore the significance of intercellular adhesion molecule -1 (CD54 or ICAM-1), epidermal growth factor receptor (EGFR) and platelet-derived factor (PDGF) in sputum cells of workers exposed to dust and patients with pneumoconiosis for the early diagnosis of pneumoconiosis. METHODS: The subjects included 62 workers exposed to dusts, 51 workers not exposed to dusts, 22 patients with pneumoconiosis and 10 healthy controls. The respiratory sputum technique was used to collect the sputum samples and the biomarkers (ICAM-1, EGFR and PDGF) of the sputum samples were detected with the sputum samples. RESULTS: When the exposure group was compared with non-exposure group, there were no significant differences of surface biomarkers (ICAM-1, EGFR and PDGF) in sputum cells (neutrophil leucocytes, macrophages, lymphocytes and acidophilic/basophil leucocytes). As compared with other workers exposed to dusts, the surface CD54 and EGFR expression levels increased significantly and the surface PDGF expression level decreased significantly in workers exposed to dusts for 10 years (P<0.05). As compared with controls, the CD54 and EGFR expression levels of sputum cells increased significantly and the PDGF expression level of sputum cells decreased significantly in patients with pneumoconiosis at the stages of I and II + mI (P<0.05). CONCLUSION: The expression levels of the surface CD54, EGFR and PDGF of sputum cells in workers exposed to dusts and patients with pneumoconiosis changed, which may be useful for early detecting pneumoconiosis.and patients is changed, which may be meaningful for early detection of pneumoconiosis.

[Involvement of Toll-like receptor in silica-induced tumor necrosis factor alpha release from human macrophage cell line].

OBJECTIVE: To characterize the role of Toll-like receptor 4 (TLR4) in silica-induced production of tumor necrosis factor alpha (TNFalpha) from macrophage cell line. METHODS: The human macrophage cell line THP-1 was incubated with silica suspension. Cell media were collected and TNFalpha levels in the supernatants measured with ELISA. To examine the involvement of TLR4 in silica-induced TNFalpha release, the neutralizing antibody (HTA125) against human TLR4 receptor was employed to pretreat THP-1 cells prior to silica treatment. Moreover, murine macrophages expressing wild type or mutated TLR4 were also treated with silica to verify the effect of TLR4 in silica-induced TNFalpha release. RESULTS: Compared with the control group [(3.18 +/- 0.41) pg/ml], the TNFalpha release in cells exposed to 100 microg/ml silica for 4 h and 8 h [(4.71 +/- 0.84), (6.22 +/- 0.58) pg/ml, respectively] increased 1.48 and 1.96 fold, respectively. Pretreatment of THP-1 cells with 20 microg/ml HTA125 antibody significantly blocked silica-induced TNFalpha release by 27%. Furthermore, the TNFalpha content released from cells expressing mutated TLR4 reduced by 30% in compared with that from the cells expressing wild type TLR4 after silica stimulation. CONCLUSION: TLR4 mediates silica-induced TNFalpha release from macrophages.

[Effects and significance of gas explosion on expression of NF-kappaB and ICAM1 in lung tissue of rats].

OBJECTIVE: To explore the expression of NF-kappaB and ICAM-1 in the gas explosion wounded lung of rats and the relationship. METHODS: Digoxin labeled NF-kappaB was used as probe. In situ hybridization was performed to detect the NF-kappaB mRNA. Immunohistochemistry was used to detect the expression of NF-kappaB and ICAM-1. RESULTS: The levels of NF-kappaB mRNA, the expression of NF-kappaB and ICAM-1 in the wounded rats were significantly increased and reached their peak two hours after injury. Pathology of lung tissue showed that some crachea epithelium mucosae were desquamated; congestion, edema of trachea wall and infiltration of neutrophilic granulocytes were found; hemorrhage, edema and infiltration of lots of inflammatory cells were present in alveolus cells. Electron microscope showed that type I, especially type II alveolus epithelia had degeneration and desquamation. CONCLUSION: The injury of gas explosion can activate NF-kappaB, which has close correlation with the acute injury to lung.

[A study on relationship between rat brain tissues hurts of the gas explosion and the expression of protein kinase CamRNA and c-fos gene.].

OBJECTIVES: To explore relationship between rat brain tissues hurts of gas explosion and the expression of Protein Kinase C alpha mRNA. METHODS: Build up rat hurt model of gas explosion. In Situ Hybridization (IDH) technique was used to test Protein Kinase C alpha mRNA. Immunohistochemical Assays (IHA) was used to determine c-fos gene protein. RESULTS: Only a little a mount expression of PKC alpha mRNA and c-fos of the control group was detected. The expression of the cerebral cortex and hippocampus of PKC alpha mRNA 24 h, 48 h and the 48 h increased obviously, and the 48 h reached the peak of expression; (t = 4.12 P < 0.01). The expression of c-fos protein of the cerebral cortex and hippocampus started to increase obviously at 0.5 h and the 4 h reached the peak, then the strength lowered gradually and the expression level came back normal level on fifth day. CONCLUSION: The anoxia of brain tissues due to the gas explosion may promote the expression of PKCamRNA, and PKCamRNA could regulate the expression of the gene of c-fos. Both PKCamRNA and the gene of c-fos are involved in harmful processes to the nerve cells.

Fibroblast growth factor 4 is required but not sufficient for the astrocyte dedifferentiation.

Our recent studies demonstrated that mature astrocytes from spinal cord can be reprogrammed in vitro and in vivo to generate neural stem/progenitor cells (NSPCs) following treatment with conditioned medium collected from mechanically injured astrocytes. However, little is known regarding the molecular mechanisms underlying the reprogramming of astrocytes. Here, we show that fibroblast growth factor 4 (FGF4) exerts a critical role in synergistically converting astrocytes into NSPCs that can express multiple neural stem cell markers (nestin and CD133) and are capable of both self-renewal and differentiation into neurons and glia. Lack of FGF4 signals fails to elicit the dedifferentiation of astrocytes towards NSPCs, displaying a substantially lower efficiency in the reprogramming of astrocytes and a slower transition through fate-determined state. These astrocyte-derived NSPCs displayed relatively poor self-renewal and multipotency. More importantly, further investigation suggested that FGF4 is a key molecule necessary for activating PI3K/Akt/p21 signaling cascades, as well as their downstream effectors responsible for directing cell reprogramming towards NSPCs. Collectively, these findings provide a molecular basis for astrocyte dedifferentiation into NSPCs after central nervous system (CNS) injury and imply that FGF4 may be a clinically applicable molecule for in situ neural repair in the CNS disorders.