Shuenn Chen Yang

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.

MicroRNA-135b promotes lung cancer metastasis by regulating multiple targets in the Hippo pathway and LZTS1

Dysregulation of microRNAs has a critical role in cancer progression. Here we identify an intronic microRNA, miR-135b that is upregulated in highly invasive non-small-cell lung cancer cells. Expression of miR-135b enhances cancer cell invasive and migratory abilities in vitro and promotes cancer metastasis in vivo, while specific inhibition of miR-135b by a miR-135b-specific molecular sponge and antagomirs suppresses cancer cell invasion, orthotopic lung tumour growth and metastasis in a mouse model. miR-135b targets multiple key components in the Hippo pathway, including LATS2, β-TrCP and NDR2, as well as LZTS1. Expression of miR-135b, LZTS1, LATS2 and nuclear TAZ predicts poor outcomes of non-small-cell lung cancer. We find that miR-135b is dually regulated by DNA demethylation and nuclear factor-kappaB signalling, implying that abnormal expression of miR-135b in cancer may result from inflammatory and epigenetic modulations. We conclude that miR-135b is an oncogenic microRNA and a potential therapeutic target for non-small-cell lung cancer.

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.

Claudin-1 Is a Metastasis Suppressor and Correlates with Clinical Outcome in Lung Adenocarcinoma

RATIONALE Claudin (CLDN)-1, a key component of tight junction complexes, was down-regulated in human lung adenocarcinomas. OBJECTIVES To investigate the clinical significance of CLDN1 expression in patients with lung adenocarcinoma and its role in cancer invasion and metastasis. METHODS We examined the CLDN1 mRNA expression in tumor specimens from 64 patients with lung adenocarcinoma and protein expression by immunohistochemistry in an independent cohort of 67 patients with lung adenocarcinoma. CLDN1 functions in cancer cell migration, invasion, and metastatic colonization were studied by overexpression and knockdown of CLDN1. Affymetrix microarrays were performed to identify gene expression changes associated with CLDN1 overexpression. MEASUREMENTS AND MAIN RESULTS We found that low-CLDN1 mRNA expression had shorter overall survival (P = 0.027, log-rank test) in 64 patients with lung adenocarcinoma, and we confirmed by immunohistochemistry that low CLDN1 expression had shorter overall survival (P = 0.024, log-rank test) in an independent cohort of 67 patients with lung adenocarcinoma. Overexpression of CLDN1 inhibited cancer cell dissociation in time-lapse imaging of wound healing, and suppressed cancer cell migration, invasion, and metastasis. Knockdown CLDN1 expression increased cancer cell invasive and metastatic abilities. Affymetrix microarrays identified a panel of genes altered by CLDN1 overexpression. CLDN1 increased expressions of cancer invasion/metastasis suppressors (e.g., connective tissue growth factor [CTGF], thrombospondin 1 [THBS1], deleted in liver cancer 1 [DLC1], occludin [OCLN], zona occludens 1 [ZO-1]) and suppressed expressions of invasion/metastasis enhancers (e.g., secreted phosphoprotein 1 [SPP1], cut-like homeobox 1 [CUTL1], transforming growth factor alpha [TGF-alpha], solute carrier family 2 [faciliated glucose transporter] member 3 [SLC2A3], placental growth factor [PGF]), supporting a role for CLDN1 as an invasion and metastasis suppressor. CONCLUSIONS CLDN1 is a cancer invasion/metastasis suppressor. CLDN1 is also a useful prognostic predictor and potential drug treatment target for patients with lung adenocarcinoma.

Trifluoperazine, an Antipsychotic Agent, Inhibits Cancer Stem Cell Growth and Overcomes Drug Resistance of Lung Cancer

RATIONALE Cancer stem cell (CSC) theory has drawn much attention, with evidence supporting the contribution of stem cells to tumor initiation, relapse, and therapy resistance. OBJECTIVES To screen drugs that target CSCs to improve the current treatment outcome and overcome drug resistance in patients with lung cancer. METHODS We used publicly available embryonic stem cell and CSC-associated gene signatures to query the Connectivity Map for potential drugs that can, at least in part, reverse the gene expression profile of CSCs. High scores were noted for several phenothiazine-like antipsychotic drugs, including trifluoperazine. We then treated lung CSCs with different EGFR mutation status with trifluoperazine to examine its anti-CSC properties. Lung CSCs resistant to epidermal growth factor receptor-tyrosine kinase inhibitor or cisplatin were treated with trifluoperazine plus gefitinib or trifluoperazine plus cisplatin. Animal models were used for in vivo validation of the anti-CSC effect and synergistic effect of trifluoperazine with gefitinib. MEASUREMENTS AND MAIN RESULTS We demonstrated that trifluoperazine inhibited CSC tumor spheroid formation and down-regulated the expression of CSC markers (CD44/CD133). Trifluoperazine inhibited Wnt/β-catenin signaling in gefitinib-resistant lung cancer spheroids. The combination of trifluoperazine with either gefitinib or cisplatin overcame drug resistance in lung CSCs. Trifluoperazine inhibited the tumor growth and enhanced the inhibitory activity of gefitinib in lung cancer metastatic and orthotopic CSC animal models. CONCLUSIONS Using in silico drug screening by Connectivity Map followed by empirical validations, we repurposed an existing phenothiazine-like antipsychotic drug, trifluoperazine, as a potential anti-CSC agent that could overcome epidermal growth factor receptor-tyrosine kinase inhibitor and chemotherapy resistance.

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.

Collapsin response mediator protein-1: A novel invasion-suppressor gene

Numerous genetic changes are associated with metastasis of cancer cells. Previously, we used microarray to identify that collapsin response mediator protein-1 (CRMP-1) was involved in cancer invasion and metastasis. We further characterized that CRMP-1 was a novel invasion-suppression gene. Members of the CRMP gene family are intracellular phosphoproteins involved in the mediation of semaphorin induced F-actin depolymerization and growth cone collapse. The precise mechanism by which CRMP-1 inhibits invasion is not yet clear. However, CRMP-1 transfected cells had fewer filopodia and less Matrigel-invasion abilities. A low expression of CRMP-1 mRNA in lung cancer tissue was significantly associated with advanced disease, lymph node metastasis, early post-operative relapse, and shorter survival. In this article, we reviewed the functions of CRMPs and semaphorins and analyzed the structure and motifs of CRMP-1 by bioinformatics. As such, we hoped to shed further light on the mechanism by which CRMP-1 suppresses the invasion of cancer cells.

Antitumor agents 288: design, synthesis, SAR, and biological studies of novel heteroatom-incorporated antofine and cryptopleurine analogues as potent and selective antitumor agents.

Novel heteroatom-incorporated antofine and cryptopleurine analogues were designed, synthesized, and tested against a panel of five cancer cell lines. Two new S-13-oxo analogues (11 and 16) exhibited potent cell growth inhibition in vitro (GI(50): 9 nM and 20 nM). Interestingly, both compounds displayed improved selectivity among different cancer cell lines, in contrast to the natural products antofine and cryptopleurine. Mechanism of action (MOA) studies suggested that R-antofine promotes dysregulation of DNA replication during early S phase, while no similar effects were observed for 11 and 15 on corresponding replication initiation complexes. Compound 11 also showed greatly reduced cytotoxicity against normal cells and moderate antitumor activity against HT-29 human colorectal adenocarcinoma xenograft in mice without overt toxicity.

Extracellular delivery of modified oligonucleotide and superparamagnetic iron oxide nanoparticles from a degradable hydrogel triggered by tumor acidosis

Chemically modified antisense RNA oligonucleotides (antagomir) offer promise for cancer therapies but suffer from poor therapeutic effect after systemic administration. Chemical modification or loading in degradable hydrogels can offer improvements in the accuracy and efficacy for sustained delivery at specific sites. In our approach, antagomir were entrapped with degradable poly(ethylene glycol) (PEG)-based hydrogels, with and without incorporation of imidazole. Superparamagnetic iron oxide nanoparticles (SPION) were simultaneously loaded with intent for magnetic resonance imaging (MRI). The incorporation of imidazole into the PEG hydrogels led to a tunable-pH-response that dictated hydrogel swelling ratio and release rate of antagomir and SPION. As a result, the PEG-imidazole hydrogel swelling ratio and degradation over a 5 week period changed up to 734% and 149% as the pH dropped from 7.4 to 6.7, respectively. The swelling ratio of PEG-imidazole hydrogels was completely reversible over repeatable cycles of pH change. The stimuli-responsive behavior of PEG-imidazole hydrogels was used for the release of antagomir and SPION under conditions consistent with tumor acidosis. This manuscript demonstrates feasibility in designing tunable-pH-responsive hydrogels for loading multimodality therapeutic and contrast agents to enhance the bioactivity of chemically modified antisense RNA oligonucleotide and SPION for acidosis-related tumor therapy and MRI imaging applications.

Long form collapsin response mediator protein-1 (LCRMP-1) expression is associated with clinical outcome and lymph node metastasis in non-small cell lung cancer patients

Collapsin response mediator protein (CRMP) family proteins are cytosolic phosphoproteins involved in semaphorin 3A-mediated neuronal cell growth cone collapse and cancer invasion. We identified a novel human isoform of CRMP family proteins named long form CRMP-1 (LCRMP-1), which was different from the known invasion suppressor, CRMP-1, in its molecular weight and the N-terminal exon-1. This study was aimed to elucidate the clinical significance of LCRMP-1 in non-small cell lung cancer (NSCLC) patients. Full-length human LCRMP-1 was cloned from lung adenocarcinoma based on the Expressed Sequence Tags (EST) database. We generated LCRMP-1 specific antibody and subsequent in vitro and in vivo invasion assays showed positive correlations between LCRMP-1 expression and lung cancer cell invasiveness. We further demonstrated that high LCRMP-1 mRNA expressions were associated with poor overall and disease-free survivals (P=0.004 and 0.006, respectively, log-rank test) in 72 NSCLC patients. The results were confirmed in an independent cohort of 54 NSCLC patients by immunohistochemistry (P=0.032, log-rank test). The metastatic lymph nodes showed higher LCRMP-1 expressions as compared with the paired primary lung tumors (P=0.012, McNemars test). In conclusion, LCRMP-1 was a cancer invasion enhancer that could be a novel prognostic biomarker in NSCLC.