Wing Kai Chan

MicroRNA Signature Predicts Survival and Relapse in Lung Cancer

We investigated whether microRNA expression profiles can predict clinical outcome of NSCLC patients. Using real-time RT-PCR, we obtained microRNA expressions in 112 NSCLC patients, which were divided into the training and testing sets. Using Cox regression and risk-score analysis, we identified a five-microRNA signature for the prediction of treatment outcome of NSCLC in the training set. This microRNA signature was validated by the testing set and an independent cohort. Patients with high-risk scores in their microRNA signatures had poor overall and disease-free survivals compared to the low-risk-score patients. This microRNA signature is an independent predictor of the cancer relapse and survival of NSCLC patients.

p53 controls cancer cell invasion by inducing the MDM2-mediated degradation of Slug

The tumour suppressor p53 is known to prevent cancer progression by inhibiting proliferation and inducing apoptosis of tumour cells. Slug, an invasion promoter, exerts its effects by repressing E-cadherin transcription. Here we show that wild-type p53 (wtp53) suppresses cancer invasion by inducing Slug degradation, whereas mutant p53 may stabilize Slug protein. In non-small-cell lung cancer (NSCLC), mutation of p53 correlates with low MDM2, high Slug and low E-cadherin expression. This expression profile is associated with poor overall survival and short metastasis-free survival in patients with NSCLC. wtp53 upregulates MDM2 and forms a wtp53–MDM2–Slug complex that facilitates MDM2-mediated Slug degradation. Downregulation of Slug by wtp53 or MDM2 enhances E-cadherin expression and represses cancer cell invasiveness. In contrast, mutant p53 inactivates Slug degradation and leads to Slug accumulation and increased cancer cell invasiveness. Our findings indicate that wtp53 and p53 mutants may differentially control cancer invasion and metastasis through the p53–MDM2–Slug pathway.

Targeting Neuropilin 1 as an Antitumor Strategy in Lung Cancer

Purpose: Neuropilin 1 (NRP1) is a mediator of lung branching and angiogenesis in embryonic development and angiogenesis in cancer. The role of NRP1 in cancer progression is not fully elucidated. We investigated the role of NRP1 in cancer invasion and tumor angiogenesis, its signaling pathways, prognostic significance, and therapeutic implications. Experimental Design: Sixty patients with non–small cell lung cancer (NSCLC) were studied. NRP1 mRNA expression was measured using real-time quantitative reverse-transcription PCR. NRP1 and cancer cell invasion, angiogenesis, and signaling pathways were studied using NRP1 stimulation by vascular endothelial growth factor 165 (VEGF165) and NRP1 inhibition by small interfering RNAs (siRNA), soluble NRP1 (sNRP1), and NRP1-inhibition peptides. The NRP1-inhibition peptides were identified using a phage display peptide library. Results: NSCLC patients with high expression of NRP1 had shorter disease-free (P = 0.0162) and overall survival (P = 0.0164; log-rank test). Multivariate analyses showed NRP1 is an independent prognostic factor in overall (HR, 2.37, 95% CI = 1.15 to 4.9, P = 0.0196) and disease-free survival [hazard ratio (HR), 2.38; 95% confidence interval (95% CI), 1.15-4.91; P = 0.0195] of NSCLC patients. Knockdown of NRP1 suppressed cancer cell migration, invasion, filopodia formation, tumorigenesis, angiogenesis, and in vivo metastasis. NRP1 signaling pathways involved VEGF receptor 2 and phosphoinositide-3-kinase (PI3K) and Akt activation. Two potent synthetic anti-NRP1 peptides, DG1 and DG2, which block NRP1 signaling pathways and suppress tumorigenesis, cancer invasion, and angiogenesis, were identified. Conclusions: NRP1 is a cancer invasion and angiogenesis enhancer. NRP1 expression is an independent predictor of cancer relapse and poor survival in NSCLC patients. NRP1 plays a critical role in tumorigenesis, cancer invasion, and angiogenesis through VEGF, PI3K, and Akt pathways. NRP1 may have potential as a new therapeutic target in NSCLC.

The ability of LCRMP-1 to promote cancer invasion by enhancing filopodia formation is antagonized by CRMP-1

Metastasis is a predominant cause of death in patients with cancer. It is a complex multistep process that needs to be better understood if we are to develop new approaches to managing tumor metastasis. Tumor cell invasion of the local stroma is suppressed by collapsin response mediator protein-1 (CRMP-1). Recently, we identified a long isoform of CRMP-1 (LCRMP-1), expression of which correlates with cancer cell invasiveness and poor clinical outcome in patients with non-small-cell lung cancer (NSCLC). Here, we report that LCRMP-1 overexpression in noninvasive human cell lines enhanced filopodia formation, cancer cell migration, and invasion via stabilization of actin. This effect required a highly conserved N-terminal region of LCRMP-1 as well as the WASP family verprolin-homologous protein-1/actin nucleation pathway (WAVE-1/actin nucleation pathway). Furthermore, LCRMP-1 appeared to act downstream of Cdc42, a Rho family protein known to be involved in actin rearrangement. In addition, LCRMP-1 associated with CRMP-1, which downregulated cancer cell metastasis by interrupting the association of LCRMP-1 and WAVE-1. Finally, we found that high-level expression of LCRMP-1 and low-level expression of CRMP-1 were associated with lymph node metastasis and poor survival in patients with NSCLC. In sum, we show that LCRMP-1 and CRMP-1 have opposing functions in regulating cancer cell invasion and metastasis and propose that this pathway may serve as a potential anticancer target.

Synergistic Activation of the Tumor Suppressor, HLJ1, by the Transcription Factors YY1 and Activator Protein 1

HLJ1 is a novel tumor and invasion suppressor that inhibits tumorigenesis and cancer metastasis. However, the mechanism of HLJ1 activation is currently unclear. Here, we identify an enhancer segment in the HLJ1 gene at -2,125 to -1,039 bp upstream of the transcription start site. A 50-bp element between -1,492 and -1,443 bp is the minimal enhancer segment, which includes the activator protein 1 (AP-1) site (-1,457 to -1,451 bp), an essential regulatory domain that binds the transcriptional factors FosB, JunB, and JunD. Chromatin immunoprecipitation assays confirm that these AP-1 family members bind to a specific site in the HLJ1 enhancer segment in vivo. Overexpression of either YY1 at promoter or AP-1 at enhancer results in a 3-fold increase in the transcriptional activity of HLJ1. We propose a novel mechanism whereby expression of the tumor suppressor, HLJ1, is up-regulated via enhancer AP-1 binding to promoter YY1 and the coactivator, p300, through DNA bending and multiprotein complex formation. The combined expression of AP-1 and YY1 enhances HLJ1 expression by more than five times and inhibits in vitro cancer cell invasion. Elucidation of the regulatory mechanism of HLJ1 expression may facilitate the development of personalized therapy by inhibiting cancer cell proliferation, angiogenesis, and metastasis.

Imprint cytology improves accuracy of computed tomography-guided percutaneous transthoracic needle biopsy

The aim of the present study was to investigate whether imprint cytology can improve the diagnostic accuracy of computed tomography-guided transthoracic core biopsy. Between October 1997 and June 2004, thoracic lesions in 622 patients underwent biopsy using 19-gauge coaxial guiding needles and 20-gauge biopsy needles under computed tomography guidance. Touch imprint cytology and histopathology were performed for all biopsy specimens. Of these lesions, 431 (74.1%) were diagnosed as malignant, 151 (25.9%) as benign and 40 (6%) as nondiagnostic. Imprint cytology plus histology shows an improved diagnostic accuracy of 96.4% compared with that of imprint cytology alone (92.3%) or histopathology alone (93.0%). Procedure-related complications requiring further treatment occurred in eight (1.4%) patients. In conclusion, imprint cytology combined with histopathology can improve the diagnostic accuracy of computed tomography-guided transthoracic needle biopsy.

Economic benefits of sponsored clinical trials on pharmaceutical expenditures at a medical center in Taiwan

Concerns exist regarding the additional cost of patient care when patients are enrolled in clinical trials at hospitals. To assess the avoidance of drug costs by conducting sponsored clinical trials, a retrospective analysis evaluating drug cost avoidance in all sponsored clinical trials was conducted in 2008 at the most prominent medical center in Taiwan. The National Health Insurance (NHI) reimbursement prices of either the investigated drugs or the standardized drug therapy for each specific disease were used to calculate the cost avoidance. Drug cost avoidance from sponsored clinical trials per year, per trial, per patient, in different therapeutic areas, and in different phases was analyzed. Three quarters of the cost avoidance in drug expenditures from 194 sponsored clinical trials were estimated. All cost values are in US Dollars. Around

CATALASE PREVENTS ESTRADIOL-INDUCED CHONDROCYTE CYTOTOXICITY

11.2 million was avoided at the center in 2008. The average value of cost avoidance was

A Five-Gene Signature and Clinical Outcome in Non–Small-Cell Lung Cancer

58,000/trial-year or

Transmission and Clinical Features of Enterovirus 71 Infections in Household Contacts in Taiwan

3,900/participant-year. The early-phase trials and phase III trials accounted for 25% and 56% of all trials, respectively, while they constituted 32% and 49% of the total costs avoided, respectively. The most frequently conducted and highest cost-avoiding trials were those for antineoplastic agents, especially targeted therapy which accounted for 85% of the total cost avoidance of anti-cancer trials. This study demonstrates the profoundly positive economic impact on the healthcare system in Taiwan by sponsored clinical trials. To understand the trend of economic benefits of the trials on pharmaceutical expenditure, it would be important to analyze the cost avoidance of trials regularly in an institution.