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author:("Fu, lieu")
1.  The tumor suppressive role of NUMB isoform 1 in esophageal squamous cell carcinoma 
Oncotarget  2014;5(14):5602-5614.
Esophageal quamous cell carcinoma (ESCC) is the predominant histological type of esophageal carcinoma in Asian populations. To date, few biomarkers have been identified for ESCC. In present study, we found a tumor suppressor, NUMB isoform 1 (NUMB-1), as a promising prognostic biomarker for patients with ESCC. NUMB-1 mRNA was downregulated in 66.7% of primary ESCC tissues when compared with matched adjacent non-tumor tissues. The low expression of NUMB-1 was significantly associated with high tumor recurrence (p=0.029) and poor post-operative overall survival (p=0.016). To further explore the underlying mechanisms by which NUMB-1 regulates ESCC, we demonstrated that ectopic expression of NUMB-1 inhibited cell proliferation through inducing G2/M phase arrest, which was accompanied by an increase in p21 and cyclin B1-cdc2 levels. However, it had no impact on apoptosis of ESCC cells. In addition, overexpression of NUMB-1 prevented epithelial-mesenchymal transition, inhibited invasion of ESCC cells and NOTCH pathway, suppressed Aurora-A activity by preventing phosphorylation of Aurora-A at T288 which resulted in cell cycle arrest. Taken together, our findings suggested NUMB-1 functions as a tumor-suppressor and serves as a prognositc biomarker for ESCC patients; thus, NUMB-1 may be a potential novel therapeutic target for treatment of ESCC.
PMCID: PMC4170621  PMID: 24980814
esophageal squamous cell carcinoma; ESCC; NUMB isoform 1; Aurora-A; G2/M arrest
2.  Elevated Orai1 expression mediates tumor-promoting intracellular Ca2+ oscillations in human esophageal squamous cell carcinoma 
Oncotarget  2014;5(11):3455-3471.
Effective treatment as well as prognostic biomarker for malignant esophageal squamous cell carcinoma (ESCC) is urgently needed. The present study was aimed at identifying oncogenic genes involving dysregulated intracellular Ca2+ signaling, which is known to function importantly in cellular proliferation and migration. Tumors from patients with ESCC were found to display elevated expression of Orai1, a store-operated Ca2+ entry (SOCE) channel, and the high expression of Orai1 was associated with poor overall and recurrence-free survival. In contrast to the quiescent nature of non-tumorigenic epithelial cells, human ESCC cells exhibited strikingly hyperactive in intracellular Ca2+ oscillations, which were sensitive to treatments with Orai1 channel blockers and to orai1 silencing. Moreover, pharmacologic inhibition of Orai1 activity or reduction of Orai1 expression suppressed proliferation and migration of ESCC in vitro and slowed tumor formation and growth in in vivo xenografted mice. Combined, these findings provide the first evidence to imply Orai1 as a novel biomarker for ESCC prognostic stratification and also highlight Orai1-mediated Ca2+ signaling pathway as a potential target for treatment of this deadly disease.
PMCID: PMC4116495  PMID: 24797725
store-operated calcium entry; STIM1; oncogenic; knockdown; xenograft
3.  UMMS-4 enhanced sensitivity of chemotherapeutic agents to ABCB1-overexpressing cells via inhibiting function of ABCB1 transporter 
Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transporters through efflux of antineoplastic agents from cancer cells is a major obstacle to successful cancer chemotherapy. The inhibition of these ABC transporters is thus a logical approach to circumvent MDR. There has been intensive research effort to design and develop novel inhibitors for the ABC transporters to achieve this goal. In the present study, we evaluated the ability of UMMS-4 to modulate P-glycoprotein (P-gp/ABCB1)-, breast cancer resistance protein (BCRP/ABCG2)- and multidrug resistance protein (MRP1/ABCC1)-mediated MDR in cancer cells. Our findings showed that UMMS-4, at non-cytotoxic concentrations, apparently circumvents resistance to ABCB1 substrate anticancer drugs in ABCB1-overexpressing cells. When used at a concentration of 20 μmol/L, UMMS-4 produced a 17.53-fold reversal of MDR, but showed no effect on the sensitivity of drug-sensitive parental cells. UMMS-4, however, did not significantly alter the sensitivity of non-ABCB1 substrates in all cells and was unable to reverse ABCG2- and ABCC1-mediated MDR. Additionally, UMMS-4 profoundly inhibited the transport of rhodamine 123 (Rho 123) and doxorubicin (Dox) by the ABCB1 transporter. Furthermore, UMMS-4 did not alter the expression of ABCB1 at the mRNA and protein levels. In addition, the results of ATPase assays showed that UMMS-4 stimulated the ATPase activity of ABCB1. Taken together, we conclude that UMMS-4 antagonizes ABCB1-mediated MDR in cancer cells through direct inhibition of the drug efflux function of ABCB1. These findings may be useful for the development of safer and more effective MDR modulator.
PMCID: PMC3960452  PMID: 24660104
UMMS-4; multidrug resistance; ATP binding cassette transporters; ABCB1; chemotherapeutic drugs
4.  Nilotinib potentiates anticancer drug sensitivity in murine ABCB1-, ABCG2-, and ABCC10-multidrug resistance xenograft models 
Cancer letters  2012;328(2):307-317.
A panel of clinically used tyrosine kinase inhibitors was compared and nilotinib was found to most potently sensitize specific anticancer agents by blocking the functions of ABCB1/P-glycoprotein, ABCG2/BCRP and ABCC10/MRP7 transporters involved in multi-drug resistance. Nilotinib appreciably enhanced the antitumor response of 1) paclitaxel in the ABCB1- and novel ABCC10-xenograft models, and 2) doxorubicin in a novel ABCG2-xenograft model. With no apparent toxicity observed in the above models, nilotinib attenuated tumor growth synergistically and increased paclitaxel concentrations in ABCB1-overexpressing tumors. The beneficial actions of nilotinib warrant consideration as viable combinations in the clinic with agents that suffer from MDR-mediated insensitivity.
PMCID: PMC3513659  PMID: 23063650
ABC transporters; ABCB1/P-gp; ABCC10/MRP7; ABCG2/BCRP; Nilotinib; multidrug resistance
5.  Identification of Five Serum Protein Markers for Detection of Ovarian Cancer by Antibody Arrays 
PLoS ONE  2013;8(10):e76795.
Protein and antibody arrays have emerged as a promising technology to study protein expression and protein function in a high-throughput manner. These arrays also represent a new opportunity to profile protein expression levels in cancer patients’ samples and to identify useful biosignatures for clinical diagnosis, disease classification, prediction, drug development and patient care. We applied antibody arrays to discover a panel of proteins which may serve as biomarkers to distinguish between patients with ovarian cancer and normal controls.
Methodology/Principal Findings
Using a case-control study design of 34 ovarian cancer patients and 53 age-matched healthy controls, we profiled the expression levels of 174 proteins using antibody array technology and determined the CA125 level using ELISA. The expression levels of those proteins were analyzed using 3 discriminant methods, including artificial neural network, classification tree and split-point score analysis. A panel of 5 serum protein markers (MSP-alpha, TIMP-4, PDGF-R alpha, and OPG and CA125) was identified, which could effectively detect ovarian cancer with high specificity (95%) and high sensitivity (100%), with AUC =0.98, while CA125 alone had an AUC of 0.87.
Our pilot study has shown the promising set of 5 serum markers for ovarian cancer detection.
PMCID: PMC3792870  PMID: 24116163
6.  Targeting cancer stem cells: a new therapy to cure cancer patients 
Cancer stem cells (CSCs) have been defined as cells within tumor that possess the capacity to self-renew and to cause the heterogeneous lineages of cancer cells that comprise the tumor. They have been identified in blood, breast, brain, colon, melanoma, pancreatic, prostate, ovarian, lung cancers and so on. It is often considered to be associated with chemo-resistance and radio-resistance that lead to the failure of traditional therapies. Most therapies are directed at the fast growing tumor mass but not the slow dividing cancer stem cells. Eradicating cancer stem cells, the root of cancer origin and recurrence, has been thought as a promising approach to improve cancer survival or even to cure cancer patients. Understanding the characteristics of cancer stem cells will help to develop novel therapies to eliminate the initiating cancer stem cell, and the relevant patents on the cancer stem cell and cancer therapy by cancer stem cells will be discussed.
PMCID: PMC3365812  PMID: 22679565
Cancer stem cell; biomarker; signal pathway; drug resistance; natural compound; Mesenchymal stem cells; differentiation therapy
7.  Marine sponge-derived sipholane triterpenoids reverse P-glycoprotein (ABCB1)-mediated multidrug resistance in cancer cells 
Biochemical pharmacology  2010;80(10):1497-1506.
Previously, we reported sipholenol A, a sipholane triterpenoid from the Red Sea sponge Callyspongia siphonella, as a potent reversal of multidrug resistance (MDR) in cancer cells that overexpressed P-glycoprotein (P-gp). Through extensive screening of several related sipholane triterpenoids that have been isolated from the same sponge, we identified sipholenone E, sipholenol L and siphonellinol D as potent reversals of MDR in cancer cells. These compounds enhanced the cytotoxicity of several P-gp substrate anticancer drugs, including colchicine, vinblastine and paclitaxel, and significantly reversed the MDR-phenotype in P-gp-overexpressing MDR cancer cells KB-C2 in a dose-dependent manner. Moreover, these three sipholanes had no effect on the response to cytotoxic agents in cells lacking P-gp expression or expressing MRP1 (ABCC1) or MRP7 (ABCC7) or breast cancer resistance protein (BCRP/ABCG2). All three sipholanes (IC50 >50 μM) were not toxic to all the cell lines that were used. [3H]-Paclitaxel accumulation and efflux studies demonstrated that all three triterpenoids time-dependently increased the intracellular accumulation of [3H]-paclitaxel by directly inhibiting P-gp-mediated drug efflux. Sipholanes also inhibited calcein-AM transport from P-gp-overexpressing cells. The Western blot analysis revealed that these three triterpenoids did not alter the expression of P-gp. However, they stimulated P-gp ATPase activity in a concentration-dependent manner and inhibited the photolabeling of this transporter with its transport substrate [125I]-iodoarylazidoprazosin. In silico molecular docking aided the virtual identification of ligand binding sites of these compounds. In conclusion, sipholane triterpenoids efficiently inhibit the function of P-gp through direct interactions and may represent potential reversal agents for the treatment of MDR.
PMCID: PMC2948058  PMID: 20696137
ABC transporter; Chemosensitivity; P-glycoprotein; sipholane triterpenoid; multidrug resistance
8.  Up-regulation of P-glycoprotein confers acquired resistance to 6-mercaptopurine in human chronic myeloid leukemia cells 
Oncology Letters  2011;2(3):549-556.
To investigate the mechanisms of cellular resistance to 6-mercaptopurine (6-MP) in chronic myeloid leukemia (CML), a 6-MP resistant cell line (K562-MP5) was established by stepwise selection of the CML cell line (K562). The results of the drug sensitivity analysis of the K562-MP5 cell line revealed the cells to be 339-fold more resistant to 6-MP compared with the parental K562 cells. K562-MP5 cells exhibited decreased accumulation and increased efflux of [14C]6-MP and its metabolites. In addition, K562-MP5 cells showed increased [3H]MTX transport. K562-MP5 cells over-expressed P-glycoprotein (P-gp) and up-regulated MDR1 mRNA levels. Taken together, these results suggest that the up-regulation of P-gp, which contributes to the decreased accumulation by increasing the efflux of 6-MP and its metabolites, underlies the mechanism of 6-MP resistance in K562 cells.
PMCID: PMC3410452  PMID: 22866119
chronic myeloid leukemia; multidrug resistance; 6-mercaptopurine; P-glycoprotein; ATP binding cassette transporter

Results 1-8 (8)