Danfeng Luo

Huazhong University of Science and Technology, Wuhan, Hubei, China

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Publications (9)34.9 Total impact

  • Article: DT390-triTMTP1, a Novel Fusion Protein of Diphtheria Toxin with Tandem Repeat TMTP1 Peptide, Preferentially Targets Metastatic Tumors.
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    ABSTRACT: Peptide-based therapies have emerged as one of the most promising therapeutics strategy in cancer-targeted therapy. Using our laboratory newly identified peptide TMTP1 and diphtheria toxin, we developed a new fusion protein that showed remarkable ability to target highly metastatic tumors. Fusion protein toxins were generated by fusing the first 390 amino acids of diphtheria toxin [truncated diphtheria toxin (DT390)] to different repeats of peptide TMTP1 (DT390-TMTP1, DT390-biTMTP1, and DT390-triTMTP1). Efficacies of the recombinant fusion proteins on tumor growth and metastasis were evaluated in vitro and in vivo. DT390-triTMTP1 showed the most powerful toxicity against cancer, which led to tumor growth retardation or regression and prolonged survival of human prostate cancer PC-3M-1E8 subcutaneously bearing or gastric cancer MKN-45 orthotopic nude mice. Increased TUNEL and caspase-3 staining and reduced ki67 staining in tumor cells suggested that the anticancer effects of DT390-triTMTP1 were through selectively inducing apoptosis and inhibiting proliferation of cancer cells. In a murine model of human orthotopic gastric carcinoma, DT390-biTMTP1 significantly inhibited metastases to liver and spleen, while DT390-triTMTP1 not only totally suppressed metastasis but also reduced primary tumors by 66.6%. In the biodistribution test, DT390-triTMTP1 was observed to home to tumor tissue rapidly and lasted over 48 h, with only a transient appearance in liver and kidney immediately after injection. Thus, our present study provided a novel recombinant fusion protein DT390-triTMTP1 with preferential targeting and high cytotoxicity, which may be a promising strategy for the targeted therapy of cancer metastasis.
    Molecular Pharmaceutics 11/2012; · 4.78 Impact Factor
  • Article: Suppression of EphB4 improves the inhibitory effect of mTOR shRNA on the biological behaviors of ovarian cancer cells by down-regulating Akt phosphorylation.
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    ABSTRACT: The aim of the present study was to examine the effects of suppression of EphB4 and/or mTOR on the biological behaviors of ovarian cancer cells, and the potential regulatory pathways. Antisense EphB4 vectors and shRNA vectors targeting mammalian target of rapamycin (mTOR) were constructed and transfected into A2780 and SKOV3 cells (two ovarian cancer cell lines). The effects of the antisense EphB4 vectors and the shRNA vectors on the proliferation, apoptosis and invasion of ovarian cancer cells were measured, and the expression of EphB4, mTOR and Akt detected. The results showed that transfection with mTOR shRNA could inhibit growth, induce apoptosis, and reduce invasive ability of ovarian cancer cells, which was accompanied by downregulation of EphB4, mTOR and Akt. The inhibitory effects on cell growth caused by mTOR shRNA alone were weaker than those by antisense pEGFP-C1-EphB4. In the antisense pEGFP-C1-EphB4-transfected cells, it was found that EphB4 knockdown could decrease the mTOR expression and slightly reduce the Akt phosphorylation. Significant suppressive effects on cell growth were observed in cells co-transfected with antisense pEGFP-C1-EphB4 and mTOR shRNA. In co-transfection group, the expression levels of EphB4, mTOR and Akt were distinctly lower than those in other groups. It was concluded that suppression of EphB4 may inhibit the growth of ovarian cancer cells by downregulation of the PI3K/Akt/mTOR pathway, and reverse Akt phosphorylation induced by mTOR shRNA. Inhibition of EphB4 and mTOR combined may cooperatively suppress the biological behaviors of ovarian cancer cells.
    Journal of Huazhong University of Science and Technology 06/2012; 32(3):358-63. · 0.38 Impact Factor
  • Article: Enhanced targeted anticancer effects and inhibition of tumor metastasis by the TMTP1 compound peptide TMTP1-TAT-NBD.
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    ABSTRACT: 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.
    Journal of Controlled Release 05/2012; 161(3):893-902. · 5.73 Impact Factor
  • Article: Anti-Tumor Effects of the Peptide TMTP1-GG-(D)(KLAKLAK)(2) on Highly Metastatic Cancers.
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    ABSTRACT: The treatment of cancer such as oligonucleotides or peptides requires efficient delivery systems. A novel peptide, TMTP1, previously derived and identified in our laboratory showed remarkable ability to target highly metastatic tumors both in vitro and in vivo, even at the early stage of occult metastasis foci. TMTP1 moderately inhibited tumor cell viability, although not enough to deem it an efficient killer of tumor cells. In this study, we sought to enhance the anti-tumor activity of TMTP1. To do this, we fused it to an antimicrobial peptide, (D)(KLAKLAK)(2), and termed the resulting peptide TMTP1-DKK. We found that TMTP1-DKK could trigger rapid apoptosis in human prostate and gastric cancer cells through both the mitochondrial-induced apoptosis pathway and the death receptor pathway. Furthermore, direct injection of TMTP1-DKK into mice with prostate and gastric xenograft cancers resulted in reduction of tumor volumes and a significant delay in tumor progression and metastasis in vivo. These results suggest that TMTP1-DKK may serve as a powerful therapeutic agent for metastatic tumors.
    PLoS ONE 01/2012; 7(9):e42685. · 4.09 Impact Factor
  • Article: TMTP1, a novel tumor-homing peptide, specifically targets hematological malignancies and their metastases.
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    ABSTRACT: TMTP1, a 5-amino acid peptide NVVRQ, obtained by using the flagella peptide library screening in our previous studies, can be used for the labeling of malignant in situ and metastatic lesions, and even micro-metastases. In this study, TMTP1 was assessed for its ability to specifically target the malignant hematopoietic cells and metastatic lesions of hematological malignancies. FITC-TMTP1 was chemically synthesized. Immunofluorescence assay and competitive test were carried out to determine the specific binding capacity of TMTPl to hematological malignant cell lines, including HL60, k562, SHI-1, Jurkat, Raji, El-4 and umbilical cord blood mononuclear cells. Mononuclear cells were isolated from the bone marrow of healthy subjects and patients with chronic myeloid leukemia. Then the cells were co-cultured with TMTP1 or scrambled peptides and the binding and affinity of TMTP1 peptide to the primary cells of hematological malignancies were flow cytometrically analyzed. The binding specificity of TMTP1 to target hematological malignancies was measured in vivo by intravenous injection of FITC-conjugated TMTP1 into El-4 lymphoma-bearing mice. The results showed that TMTP1 specifically bound to the cells of a series of hematological malignancies, including HL60, k562, Jurkat, Raji, El-4 and chronic myeloid leukemia primary cells but not to bone marrow mononuclear cells from healthy subjects. By contrast, TMTP1 could bind to the metastatic foci of lymphoma originating from the EL-4 cell line while the scrambled peptide failed to do so. Moreover, the occult metastases could be identified, with high specificity, by detecting FITC-TMTP1. We are led to conclude that TMTP1, as a novel tumor-homing peptide, can serve as a marker for primary malignant and metastatic lesions for the early diagnosis of hematological malignances and a carrier of anticancer drugs for cancer treatment.
    Journal of Huazhong University of Science and Technology 10/2011; 31(5):608-13. · 0.38 Impact Factor
  • Article: A novel oncolytic adenovirus selectively silences the expression of tumor-associated STAT3 and exhibits potent antitumoral activity.
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    ABSTRACT: Tumor cells acquire the ability to proliferate uncontrollably, resist apoptosis, sustain angiogenesis and evade immune surveillance. Signal transducer and activator of transcription (STAT) 3 regulates all of these processes in a surprisingly large number of human cancers. Consequently, the STAT3 protein is emerging as an ideal target for cancer therapy. This paper reports the generation of an oncolytic adenovirus (M4), which selectively blocks STAT3 signaling in tumor cells as a novel therapeutic strategy. M4 selectively replicated in tumor cells and expressed high levels of antisense STAT3 complementary DNA during the late phase of the viral infection in a replication-dependent manner. The viral progeny yield of M4 in tumor cells was much higher than that of the parent adenoviral mutants, Ad5/dE1A. M4 effectively silenced STAT3 and its target genes in tumor cells while sparing normal cells and exhibited potent antitumoral efficacy in vitro and in vivo. Systemic administration of M4 significantly inhibited tumor growth in an orthotopic gastric carcinoma mouse model, eliminated abdominal cavity metastases and prolonged survival time. In summary, M4 has low toxicity and great potential as a therapeutic agent for different types of cancers.
    Carcinogenesis 10/2009; 30(12):2014-22. · 5.70 Impact Factor
  • Article: TMTP1, a novel tumor-homing peptide specifically targeting metastasis.
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    ABSTRACT: Tumor metastasis continues to be the major obstacle to cancer therapy and the leading cause of cancer-related death. Methods used to detect metastasis, especially occult metastases, have received a great deal attention. In this study, a novel selective peptide was assessed for its specific binding to metastasis. The FliTrx bacterial peptide display system, an alternative to phage peptide display, was used to identify a 5-amino acid peptide termed TMTP1 (NVVRQ), which binds to the highly metastatic prostate cancer cell line PC-3M-1E8. The synthetic TMTP1 was tested in vitro for its binding specificity and affinity to highly metastatic cancer cells. The tumor targeting assays were done in vivo by i.v. injection of FITC-conjugated TMTP1 into tumor-bearing mice. TMTP1 specifically bound to a series of highly metastatic tumor cells, including prostate cancer PC-3M-1E8, breast cancer MDA-MB-435S, lung cancer PG-BE1, and gastric cancer MKN-45sci, in vitro and in vivo but not to the poorly metastatic or nonmetastatic cell line, including prostate cancer PC-3M-2B4, breast cancer MCF-7, lung cancer PG-LH7, or murine fibroblast cell NIH/3T3. FITC-TMTP1 strongly and specifically targeted the metastasis foci in tumor-bearing mice 24 h after i.v. peptide injection. Moreover, the occult metastases were specifically detected by FITC-TMTP1. Our results suggest that TMTP1 is a potential strategy for the development of new diagnostic tracers or alternative anticancer agents for tumor metastasis.
    Clinical Cancer Research 10/2008; 14(17):5494-502. · 7.74 Impact Factor
  • Article: Antisense Ki-67 cDNA transfection reverses the tumorigenicity and induces apoptosis in human breast cancer cells.
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    ABSTRACT: Effects of antisense Ki-67 cDNA transfection on breast cancer cells were investigated in this study. Transfection of antisense Ki-67 cDNA resulted in a 70%-80% reduction in proliferation of MDA-MB-435s, cells which highly expressed Ki-67 mRNA and protein. Transwell assay showed that mobility and invasion capability was dramatically inhibited by 50%-60%, and cell cycle analysis displayed a higher proportion in G(2)/M and G(0)/G(1) phases accompanied by remarkably increased ratio of apoptotic cells. Our results suggested that antisense Ki-67 cDNA vector treatment might be an important potential option in the anticancer therapy.
    Cancer Investigation 10/2008; 26(8):830-5. · 1.85 Impact Factor
  • Article: Deletion of the intracellular domain of coxsackie and adenovirus receptor (CAR) enhances the expression of itself and boosts the efficiency of current adenovirus-mediated gene therapy in ovarian cancer cell lines in vitro.
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    ABSTRACT: The failure of adenovirus-mediated gene therapy often derives from the absence of coxsackie and adenovirus receptor (CAR) expression in target cells. We hypothesize that the slight up-regulation of CAR expression might boost the effect of adenovirus-mediated gene therapy in ovarian cancer. To test this hypothesis, we transfected full-length and intracellular-domain-deleted (tailless) CAR plasmids into CAR-deficient ovarian cancer cell line SKOV3. We observed significant elevations of the in vitro killing effect of Adv-TK and oncolytic adenovirus-mediated cytopathic effect (CPE) in transfected sub-clones, and tailless-transfected SKOV3 showed higher CAR expressions than full-length CAR-transfected cells. We conclude that the extracellular domain of CAR is essential for adenovirus-based gene therapy and, furthermore, that its intracellular domain might play an important role in the regulation of its own expression.
    Cancer Letters 05/2007; 248(2):299-307. · 4.24 Impact Factor