Melatonin: A promising agent targeting leukemia

Leukemia or cancer of blood is a well-known cancer, which affects a range of people from newborns to the very old. It is a public health problem throughout the world. By way of treatment, due to the lack of specific anticancer therapies, common treatments of leukemia lead to severe side effects. Nonspecific anticancer drugs result in inhibition of normal cell growth and thereby their necrosis. Moreover, drug resistance is an additional problem, which stands in the way of leukemia treatment. Thus, finding new treatments for leukemia is essential. Melatonin, as a natural product, has been shown to be effective in a wide variety of diseases such as coronary heart disease, schizophrenia, chronic pain, and Alzheimer's disease. In addition, melatonin levels have been observed to be altered in different cancers, such as breast cancer, colorectal cancer endometrial cancer, and hematopoetical cancers. Anticancer features of melatonin such as pro-oxidation, apoptosis induction, antiangiogenesis property and metastasis and invasion inhibition suggest that this natural compound can be used as a potential agent in novel therapeutic strategies for cancers. Also, it has been reported that melatonin has positive and protective effects on different physiological reactions and in normal bone marrow cells suggesting effectiveness in leukemia therapy. Thus, the aim of our paper was to depict and summarize the main molecular targets of melatonin on leukemia models.     

Agarose: a possible universal gel exclusion agent

Granulated agarose gels suitable for gel exclusion chromatography of proteins of any molecular weight may now be prepared. This was made possible by the observation that agarose solutions of 16% polysaccharide may be prepared by displacing 8% agarose from solution with 8% polyethylene glycol Mr 6000. The displaced polysaccharide concentrates in a viscous mass occupying half the volume of the original carbohydrate solution. By diluting the displaced polysaccharide with hot watery solutions of electrolyte and allowing the solutions to congeal, gels of any desired concentration, ranging from low to the maximum of 16%, may be prepared.     

A recombinant scFv-FasLext as a targeting cytotoxic agent against human Jurkat-Ras cancer

Background

Targeted therapy of human cancers is an attractive approach and has been investigated with limited success. We have developed novel cytotoxic agents for targeted therapy of human cancers based on the extracellular cytotoxicity domain of CD178 (FasL) and the specificity offered by single chain antibodies (scFv) against dominant human tumor Ag TAG-72 (cc49scFv) and TAL6 (L6scFv).

Results

The cc49scFv-FasL_ext is highly effective in in vitro killing of human TAG-72⁺ Jurkat-Ras tumor cells with a 30,000 fold greater cytotoxicity as compared to soluble FasL (sFasL). On the other hand, L6scFv-FasL_ext only increased cytotoxicity 500-fold as compared with sFasL against TAL6⁺ HeLa cells in in vitro assays. The high specificity and strong cytotoxicity of cc49scFv-FasL_ext made it feasible to cure IP-implanted Jurkat-Ras tumors in SCID mice.

Conclusion

Our study demonstrated that scFv-FasL_ext with a strong cytotoxicity against sensitive human tumor targets may be useful as effective chemotherapeutic agents.     

A new optical and nuclear dual-labeled imaging agent targeting interleukin 11 receptor alpha-chain

Optical imaging has great potential for studying molecular recognitions both in vivo and in vitro, yet nuclear imaging is the most effective clinical molecular imaging modality. The combination of optical and nuclear imaging modalities may provide complementary information for improving diagnosis and management of diseases. In this study we developed an optical and nuclear dual-labeled imaging agent, 111In-DTPA-Bz-NH-SA-K(IR-783-S-Ph-CO)-c(CGRRAGGSC)NH2, called DLIA-IL11Ralpha. 111In-DTPA-Bz-NH-SA is the radiotracer moiety; a near-infrared dye IR-783-S-Ph-COOH serves as the fluorescent emitter; and the cyclic peptide c(CGRRAGGSC), which is known to target interleukin 11 receptor alpha-chain (IL-11Ralpha), delivers the desired imaging agent to its target. Experiments revealed that the cyclic peptide c(CGRRAGGSC) continued to possess the targeting capability to IL-11Ralpha after the conjugation of the optical and nuclear tracers. Furthermore, the presence of the metal isotope chelator did not cause quenching of fluorescence emission. The cross validation and direct comparison of optical and nuclear imaging of a tumor was achieved using a single injection, and the preliminary results show the conjugate has tumor targeting capabilities in vivo.     

A novel 99mTc-labeled testosterone derivative as a potential agent for targeting androgen receptors

With an insight that ligands possessing a N2S2 tetradentate array of donor atoms serve as ideal bifunctional chelating agents (BFCA) in the radiolabeling of target-specific agents, 5-hydroxy-3,7-diazanonan-1,9-dithiol (DAHPES) with a derivatizable substituent in the form of a hydroxyl group in the backbone was synthesized. The preparation of a steroid conjugate via coupling of this BFCA with testosterone-3-(O-carboxymethyl) oxime and the subsequent radiolabeling of the conjugate under optimized conditions with 99mTc, the ideal diagnostic radionuclide in nuclear medicine procedures, are reported. The immunoreactivity of the radiolabeled conjugate was demonstrated in a study using anti-testosterone antibodies, wherein the radiolabeled conjugate exhibited significant binding with antiserum to testosterone. Cell-uptake studies in DU145 prostate carcinoma cell line bearing androgen receptors (ARs) and comparison with AR non-bearing breast carcinoma cell line revealed the specific binding of the steroidal moiety with the testosterone receptor.     

Signal recognition particle-dependent protein targeting, universal to all kingdoms of life

The signal recognition particle (SRP) and its membrane-bound receptor represent a ubiquitous protein-targeting device utilized by organisms as different as bacteria and humans, archaea and plants. The unifying concept of SRP-dependent protein targeting is that SRP binds to signal sequences of newly synthesized proteins as they emerge from the ribosome. In eukaryotes this interaction arrests or retards translation elongation until SRP targets the ribosome-nascent chain complexes via the SRP receptor to the translocation channel. Such channels are present in the endoplasmic reticulum of eukaryotic cells, the thylakoids of chloroplasts, or the plasma membrane of prokaryotes. The minimal functional unit of SRP consists of a signal sequence-recognizing protein and a small RNA. The as yet most complex version is the mammalian SRP whose RNA, together with six proteinaceous subunits, undergo an intricate assembly process. The preferential substrates of SRP possess especially hydrophobic signal sequences. Interactions between SRP and its receptor, the ribosome, the signal sequence, and the target membrane are regulated by GTP hydrolysis. SRP-dependent protein targeting in bacteria and chloroplasts slightly deviate from the canonical mechanism found in eukaryotes. Pro- and eukaryotic cells harbour regulatory mechanisms to prevent a malfunction of the SRP pathway. Electronic Publication     

基于流行性感冒病毒保守区域的通用流行性感冒疫苗的研究进展

流行性感冒(流感)疫情频频暴发,严重危害人类健康和公共卫生。虽然接种流感疫苗能够起到有效的预防作用,但由于流感病毒易变异,使得流感疫苗只对疫苗株或与疫苗株高度相近的病毒株具有保护效果。因此,研制一种可抵御不同型或亚型流感病毒的通用疫苗成为流感疫苗研究的热点。现就基于流感病毒保守区域的通用流感疫苗的研究进展作一综述。     

Targeted bioactivity of membrane-anchored TNF by an antibody-derived TNF fusion protein

We describe the generation and characterization of a fusion protein consisting of a humanized anti-fibroblast-activating protein (anti-FAP) Ab and human TNF replacing the IgG1 CH2/CH3 Fc domain. The construct was generated by recombinant DNA technology and preserved its IgG1-derived dimeric structure with the TNF molecule linked as a dimer. Expression in CHO cells was optimized in serum-free medium under GMP conditions to achieve production levels up to 15 mg/liter. Recognition of the FAP Ag by the construct was as good as that by the parental anti-FAP Ab. TNF signaling was induce able via both TNF receptor types. When acting in solution, the Ab-linked TNF dimer exhibited a 10- to 20-fold lower activity compared with recombinant trimeric TNF. However, after binding to FAP-expressing cells, immobilized anti-FAP-TNF dimer was equivalent to membrane-anchored TNF with regard to bioactivity. Amplification of TNF-related pathways by mimicking the membrane-integrated TNF signaling was detectable in various systems, such as apoptosis induction or tissue factor production. The difference in TNF receptor type 1 and 2 signaling by the anti-FAP-TNF construct correlated well with its Ag-bound or -soluble status. Translating the approach into a xenograft animal model (BALB/c nu/nu mice), we demonstrated low toxicity with measurable antitumor efficacy for the TNF fusion protein after i.v. application. Immunohistochemical analysis of tumor sections showed restricted TNF-mediated macrophage recruitment to the targeted tissue in a time- and dose-dependent manner. These data warrant transfer of the anti-FAP-TNF immunocytokine into clinical trials for the treatment of FAP-positive tumors.     

A growth factor antagonist as a targeting agent for sterically stabilized liposomes in human small cell lung cancer

The ability of a growth factor antagonist, [D-Arg(6),D-Trp(7,9)-N(me)Phe(8)]-substance P(6-11), named antagonist G, to selectively target polyethylene glycol-grafted liposomes (known as sterically stabilized liposomes) to a human classical small cell lung cancer (SCLC) cell line, H69, was examined. Our results showed that radiolabeled antagonist G-targeted sterically stabilized liposomes (SLG) bound to H69 cells with higher avidity than free antagonist G and were internalized (reaching a maximum of 13000 SLG/cell), mainly through a receptor-mediated process, likely involving clathrin-coated pits. This interaction was confirmed by confocal microscopy to be peptide- and cell-specific. Moreover, it was shown that SLG significantly improved the nuclear delivery of encapsulated doxorubicin to the target cells, increasing the cytotoxic activity of the drug over non-targeted liposomes. In mice, [(125)I]tyraminylinulin-containing SLG were long circulating, with a half-life of 13 h. Use of peptides like antagonist G to promote binding and internalization of sterically stabilized liposomes, with their accompanying drug loads, i.e., anticancer drugs, genes or antisense oligonucleotides, into target cells has the potential to improve therapy of SCLC.     

A universal simulator for ecological models

Software design is an often neglected issue in ecological models, even though bad software design often becomes a hindrance for re-using, sharing and even grasping an ecological model. In this paper, the methodology of agile software design was applied to the domain of ecological models. Thus the principles for a universal design of ecological models were arrived at. To exemplify this design, the open-source software Universal Simulator was constructed using C++ and XML and is provided as a resource for inspiration.     

Discovery of CYT997: a structurally novel orally active microtubule targeting agent

CYT997 was discovered as a potent tubulin polymerization inhibitor possessing potent cytotoxic activity against a range of cancer cells. Details of SAR studies, pharmacokinetic investigations and synthesis of compounds leading to the discovery of CYT997 are reported.     

Identification of ML-9 as a lysosomotropic agent targeting autophagy and cell death

The growing number of studies suggested that inhibition of autophagy enhances the efficacy of Akt kinase inhibitors in cancer therapy. Here, we provide evidence that ML-9, a widely used inhibitor of Akt kinase, myosin light-chain kinase (MLCK) and stromal interaction molecule 1 (STIM1), represents the ‘two-in-one'' compound that stimulates autophagosome formation (by downregulating Akt/mammalian target of rapamycin (mTOR) pathway) and inhibits their degradation (by acting like a lysosomotropic agent and increasing lysosomal pH). We show that ML-9 as a monotherapy effectively induces prostate cancer cell death associated with the accumulation of autophagic vacuoles. Further, ML-9 enhances the anticancer activity of docetaxel, suggesting its potential application as an adjuvant to existing anticancer chemotherapy. Altogether, our results revealed the complex effect of ML-9 on autophagy and indentified ML-9 as an attractive tool for targeting autophagy in cancer therapy through dual inhibition of both the Akt pathway and the autophagy.     

A universal type IA topoisomerase fold

A class of enzymes, called DNA topoisomerases, is responsible for controlling the topological state of cellular DNA. Among these, type IA topoisomerases form a vast family that is present in all living organisms, including higher eukaryotes, in which they play important roles in genome stability. The known 3D structures of three of these enzymes indicate that they share a common toroidal architecture. We previously showed that the toroidal structure could be split off from the core enzyme of Thermotoga maritima topoisomerase I by limited proteolysis. This structure is produced by the association of two tandemly repeated elementary folds in a head-to-tail orientation. By using a combination of structural and sequence data analysis, we show that the elementary fold of about 150 amino acid residues, referred to as the topofold, is likely to be present in the whole topoisomerase IA family. Within each enzyme, the successive topofolds share two conserved sequence motifs located at the base of the ring, and referred to as the MI and MII motifs. However, the overall sequences of the folds have largely diverged. By contrast, secondary and tertiary structures appear remarkably conserved. We suggest that this twofold repeat has evolved by gene duplication/fusion from an ancestral topofold.     

Oligonucleotide conjugate GRN163L targeting human telomerase as potential anticancer and antimetastatic agent

Telomerase is one of the key enzymes responsible for the proliferative immortality of the majority of cancer cells. We recently introduced a new telomerase inhibitor, a 13-mer oligonucleotide N3' --> P5'-thio-phosphoramidate lipid conjugate, designated as GRN163L. This compound inhibits telomerase activity in various tumor cell lines with IC(50) values of 3-300 nM without any cellular uptake enhancers. GRN163L demonstrated potent and sequence specific anti-cancer activity in vivo in multiple animal models. This compound was able to significantly affect not only the growth of primary tumors, but also the spread and proliferation of metastases. GRN163L is currently in Phase I and Phase I/II clinical studies in patients with solid tumors and CLL, respectively.     

Oridonin: targeting programmed cell death pathways as an anti‐tumour agent

Oridonin, an active diterpenoid isolated from traditional Chinese herbal medicine, has drawn rising attention for its remarkable apoptosis‐ and autophagy‐inducing activity and relevant molecular mechanisms in cancer therapy. Apoptosis is a well known type of cell death, whereas autophagy can play either pro‐survival or pro‐death roles in cancer cells. Accumulating evidence has recently revealed relationships between apoptosis and autophagy induced by oridonin; however, molecular mechanisms behind them remain to be discovered. In this review, we focus on highlighting updated research on oridonin‐induced cell death signalling pathways implicated in apoptosis and autophagy, in many types of cancer. In addition, we further discuss cross‐talk between apoptosis and autophagy induced by oridonin, in cancer. Taken together, these findings open new perspectives for further exploring oridonin as a potential anti‐tumour agent targeting apoptosis and autophagy, in future anti‐cancer therapeutics.     

A universal method for automated gene mapping

Small insertions or deletions (InDels) constitute a ubiquituous class of sequence polymorphisms found in eukaryotic genomes. Here, we present an automated high-throughput genotyping method that relies on the detection of fragment-length polymorphisms (FLPs) caused by InDels. The protocol utilizes standard sequencers and genotyping software. We have established genome-wide FLP maps for both Caenorhabditis elegans and Drosophila melanogaster that facilitate genetic mapping with a minimum of manual input and at comparatively low cost.