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VEGFR-3 plays an indispensable role in lymphangiogenesis. Previous findings suggest that blocking the VEGFR-3 signaling pathway can inhibit lymph node metastasis effectively, thus reduce the incidence of distant metastasis. The development of new VEGFR-3 targeting drugs for early detection and effective treatments is, therefore, urgently requied. Here, in vitro biopanning of a phage-displayed peptide library was used to identify specific peptides binding to the extracellular domain of VEGFR-3. We obtained a novel VEGFR-3 targeting peptide TMVP1 (LARGR), our combined immunofluorescence and radiopharmaceutical studies revealed that FITC-TMVP1 and 99mTc-labeled TMVP1 specifically accumulated in VEGFR-3 positive lymphatic vessels of tumors after i.v administration in tumor xenograft models in vivo. The accumulation of the TMVP1 in lymphatic vessels was specific, because this accumulation can be significantly reduced by blocking experiments. To enhance the therapeutic efficacy of anticancer drugs, we fused TMVP1 to a proapoptotic peptide D(KLAKLAK)2, the fusion peptide strongly inhibited tumor lymphangiogenesis in vitro and in vivo, and specifically suppressed lung metastasis in a 4T1 breast cancer xenograft model. Our results suggest that TMVP1 is a promising therapeutic strategy for the development of new diagnostic tracers or alternative anticancer agents for tumor lymphangiogenesis and lymphatic metastasis.

E-cadherin is a key cell-to-cell adhesion molecule associated with the invasion and metastasis of tumor cells; however, the molecular mechanisms are not entirely understood. In this study, we investigated whether downregulation of E-cadherin by E-cadherin-specific small intefering RNA (siRNA) was able to promote malignant phenotypes of prostate cancer cells through upregulating the metastasis-associated gene 1 (MTA1) in vitro. The expression levels of E-cadherin in human paired prostate adenocarcinoma cell lines, PC-3M-2B4 (2B4) and PC-3M-1E8 (1E8), were investigated using western blot analysis. The alteration of malignant phenotypes associated with decreasing E-cadherin expression were assessed in 2B4 cells using wound-healing assays, solid-phase adhesion assays, invasion assays and cytoskeletal staining. The expression of E-cadherin and MTA1 in normal, localized and metastatic prostate cancer cells was analyzed using immunohistochemistry. Downregulation of E-cadherin using an RNA interference approach led to the upregulation of MTA1 expression, decreased tumor cell adhesion ability as well as enhanced cell mobility, invasion and cellular polarity compared with the controls (P

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively kill tumor cells and enhance therapy in vivo. However, concerns regarding its considerable liver toxicity limit its use in humans as a cancer therapy. Tumor molecular targeted peptide 1 (TMTP1) has previously been reported by our laboratory to target primary tumors and metastatic foci. Here, we report a novel recombinant fusion protein, sTRAIL-TMTP1, which not only induced apoptosis in cancer cells in vitro but also inhibited tumor growth and metastases in vivo. Moreover, sTRAIL-TMTP1 impacted tumor angiogenesis. The biodistribution results demonstrated that sTRAIL-TMTP1 accumulation peaked 6 h after injection and persisted for 24 h in the tumor, while faint sTRAIL-TMTP1 accumulation was detected in normal organs in tumor-bearing mice. Thus, combining sTRAIL with TMTP1 resulted in high anti-tumor activity and low toxicity. In conclusion, the novel fusion protein sTRAIL-TMTP1 was successfully developed in our laboratory and was observed to induce apoptosis both in primary and metastatic cancer, which may lead to the development of novel, targeted anticancer agents.Construction, purification, and characterization of the novel recombinant fusion protein, sTRAIL-TMTP1. sTRAIL-TMTP1 not only induce apoptosis in cancer cells but inhibit tumor growth and metastasis. sTRAIL-TMTP1 showed an impact on caspase activity and tumor angiogenesis. sTRAIL-TMTP1's accumulate in tumor with little accumulation in normal organs.

Micromolecular agents that block tumor development and metastasis hold great promise as cancer-targeted therapies. Tumor molecular targeted peptide 1 (TMTP1) was previously shown to target primary tumors and metastatic foci specifically. In this study, a group of composite peptides were incorporated to TMPT1. The NF-κB essential modulator-binding domain (NBD), and the trans-activator of transcription (TAT) peptide, were synthesized to enhance the targeted anti-tumor effects of TMTP1. TMTP1-NBD did not exhibit strong affinity to tumor cells as we had expected. Conjugating TAT with TMTP1-NBD ameliorated the poor hydrophilicity and negative charge of TMTP1-NBD. Therefore TMTP1-TAT-NBD displayed strong affinity and anti-tumor effects as we expected in vivo and in vitro. Interestingly cytoplasmic glycogen accumulation as well as apoptosis was observed in TMTP1-TAT-NBD treated PC-3M-1E8 cells. The downstream signaling pathways including AKT, GSK-3β, IκBα and NF-κB activity were verified to decrease by TMTP1-TAT-NBD. The pharmacokinetics and distribution of TMTP1-TAT-NBD in MDA-MB-231 tumor-bearing mice model provided some evidence for safety of the composite peptide, which showed the fluorescence of the peptide peaked in the tumor 6h after injection, with little fluorescence detected in normal organs except for very weak fluorescence in kidney. In conclusion, TMTP1-TAT-NBD may be a promising targeted anti-tumor agent for primary tumor and metastatic foci, which enhances the anticancer effects through inhibiting the AKT/GSK-3β/NF-κB pathway comparing with TMTP1.

Human metastasis-associated gene 1 (MTA1) is highly associated with the metastasis of prostate cancer; however, the molecular functions of MTA1 that facilitate metastasis remain unclear. In this study, we demonstrate that the silencing of MTA1 by siRNA treatment results in the upregulation of E-cadherin expression by the phosphorylation of AKT (p-AKT) and decreases the invasiveness of prostate cancer cells. We show that MTA1 is expressed in over 90% of prostate cancer tissues, especially metastatic prostate cancer tissue, comparing to non-expression in normal prostate tissue. RT-PCR analysis and Western blot assay showed that MTA1 expression is significantly higher in highly metastatic prostate cancer PC-3M-1E8 cells (1E8) than in poorly metastatic prostate cancer PC-3M-2B4 cells (2B4). Silencing MTA1 expression by siRNA treatment in 1E8 cells increased the cellular malignant characters, including the cellular adhesive ability, decreased the cellular invasive ability and changed the polarity of cellular cytoskeleton. 1E8 cells over-expressing MTA1 had a reduced expression of E-cadherin, while 1E8 cells treated with MTA1 siRNA had a higher expression of E-cadherin. The expression of phosphorylated AKT (p-AKT) or the inhibition of p-AKT by wortmannin treatment (100 nM) significantly altered the function of MTA1 in the regulation of E-cadherin expression. Alterations in E-cadherin expression changed the role of p-AKT in cellular malignant characters. All of these results demonstrate that MTA1 plays an important role in controlling the malignant transformation of prostate cancer cells through the p-AKT/E-cadherin pathway. This study also provides a new mechanistic role for MTA1 in the regulation of prostate cancer metastasis.

It has been reported that metastasis-associated gene 1 (Mta1) is overexpressed in many malignant tumors with high metastatic potential. In addition, some studies indicated that MTA1 participated in invasion, metastasis, and survival of cancer cells by regulating cell migration, adhesion and proliferation. But the role of MTA1 is unclear in vitro in the development of cervical cancer cells. This study investigated whether and how MTA1 mediated cell proliferation, migration, invasion and adhesion in cervical cancer. MTA1 expression level was detected by Western blot in two cervical cancer cell lines of different invasion potentials. The effects of MTA1 expression on SiHa cell apoptosis, cycle, proliferation, migration, invasion and adhesion were tested by flow cytometry, MTT, wound-healing assay, Transwell assay and adhesion assay, respectively. The expression levels of p53, E-cadherin, and β-catenin activity were evaluated in untreated and treated cells. The results showed that MTA1 protein expression was significantly higher in SiHa than in HeLa, which was correlated well with the potential of migration and invasion in both cell lines. Furthermore, the cell invasion, migration and adhesion capabilities were decreased after inhibition of MTA1 expression mediated by Mta1-siRNA transfection in SiHa. However, no significant differences were found in cell apoptosis, cycle, and proliferation. In addition, E-cadherin and p53 protein levels were significantly up-regulated, while β-catenin was significantly down-regulated in SiHa transfected with the siRNA. These results demonstrated that MTA1 played an important role in the migration and invasion of cervical cancer cells. It was speculated that the decreased migration and invasion capability by inhibiting the MTA1 expression in the SiHa cell line may be mediated through the altered expression of p53, and E-cadherin/β-catenin complex. MTA1 could serve as a potential therapeutic target in cervical cancer.