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Biomedical subjects

M Nomizu

Publications and source records attributed to M Nomizu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Initiation of skin basement membrane formation at the epidermo-dermal interface involves assembly of laminins through binding to cell membrane receptors.

To study the mechanism of basement membrane formation, we determined by immunochemistry temporal and spatial expression of laminin-5 (Ln-5), laminin-1 (Ln-1) and their integrin receptors during early skin morphogenesis. A 3-dimensional skin culture was used that allows the study of the sequential molecular events of basement membrane formation at the epidermodermal interface. During early anchorage of keratinocytes to the extracellular matrix there is expression of Ln-5, BP-230 antigen and alpha3, beta1 integrin subunits. During epidermal stratification and prior to the formation of the lamina densa there is assembly of Ln-5, Ln-1, collagen IV and nidogen accompanied by keratinocyte basal clustering of alpha2, alpha3, alpha6, beta1, and beta4+ integrin subunits. The assembly pattern of Ln-1 and Ln-5 can be disturbed with functional antibodies against the beta1 (AIIB2) and alpha6 (GoH3) integrin subunits. Ln-1 assembly can also be disturbed with antibodies against its E8 domain and by competitive inhibition with a synthetic peptide (AG-73) derived from its G-4 domain. Quantitative RT-PCR showed that the dermis contributes about 80% of the laminin gamma)1 chain mRNA while 20% is produced by the epidermis which emphasizes its dual tissue origin and the major contribution of the mesenchyma in laminin production. The laminin gamma2 chain mRNA, present in Ln-5, was mostly of epidermal origin. This study presents evidence that during the initiation of basement membrane formation, laminins bind to keratinocyte plasma membrane receptors and thus may serve as nucleation sites for further polymerization of these compounds by a self-assembly process.

Actin Cytoskeleton↗
PubMed1998

Activation of beta1 integrin signaling stimulates tyrosine phosphorylation of p190RhoGAP and membrane-protrusive activities at invadopodia.

The ligation of available alpha6beta1 integrin in adherent LOX melanoma cells by laminin G peptides and integrin stimulatory antibodies induced cell invasiveness, independent of adhesion activity of integrins that were pre-bound to extracellular matrix (Nakahara, H., Nomizu, M., Akiyama, S. K., Yamada, Y., Yeh, Y., and Chen, W.-T. (1996) J. Biol. Chem. 271, 27221-27224). Here, we show that this induced invasion involves an increase in tyrosine phosphorylation of a 190-kDa GTPase-activating protein for Rho family members (p190(RhoGAP); p190) and membrane-protrusive activities at invadopodia. This tyrosine phosphorylation does not occur when the adherent cells are treated with non-activating antibody against beta1 integrin, control laminin peptides, or tyrosine kinase inhibitors genistein and herbimycin A. Although p190 and F-actin co-distribute in all cell cortex extensions, tyrosine-phosphorylated proteins including p190 appear to associate with F-actin specifically in invadopodia. In addition, the localized matrix degradation and membrane-protrusive activities were blocked by treatment of LOX cells with tyrosine kinase inhibitors as well as microinjection of antibodies directed against p190 but not by non-perturbing antibodies or control buffers. We suggest that activation of the alpha6beta1 integrin signaling regulates the tyrosine phosphorylation state of p190 which in turn connects downstream signaling pathways through Rho family GTPases to actin cytoskeleton in invadopodia, thus promoting membrane-protrusive and degradative activities necessary for cell invasion.

Amino Acid Sequence↗
PubMed1998

Laminin alpha1 chain G domain peptide, RKRLQVQLSIRT, inhibits epithelial branching morphogenesis of cultured embryonic mouse submandibular gland.

Active sequences from the laminin alpha1 and alpha2 chain carboxyl-terminal globular domains (G domain) have been identified by screening overlapping synthetic peptides in a number of biological assays (Nomizu et al. [1995] J. Biol. Chem. 270:20583-20590; Nomizu et al. [1996] FEBS Lett. 396:37-42). We have tested the activity of these peptides in submandibular gland explants of embryonic day 13 mice to determine the functional sites involved in organ development. The laminin alpha1 chain peptide, RKRLQVQLSIRT (residues 2719-2730 and designated AG-73), significantly inhibited epithelial branching morphogenesis. In contrast, other cell adhesive laminin alpha1 chain peptides including the AASIKVAVSADR and NRWHSIYITRFG failed to inhibit the branching. MG-73, a homologue of AG-73 from the laminin alpha2 chain, did not inhibit the branching. The alpha2 chain peptide had no effect, which may be due to the low levels of this laminin chain in day 13 mice. Laminin alpha2 chain-specific monoclonal antibodies strongly reacted with the basement membranes of developed acini but only weakly stained embryonic day 13 submandibular epithelium. The expression of E-cadherin and alpha6 integrin, as detected by immunofluorescence, were unchanged in both AG-73 and control scramble peptide-treated epithelial cells of the explants. In contrast, immunostaining of nidogen/entactin showed that explants treated with AG-73 for 3 days had a discontinuous basement membrane. Explants treated for 3 days with control peptide showed a normal basement membrane. These results suggest that the region containing the AG-73 sequence of the laminin alpha1 chain is crucial for development of submandibular gland at early embryonic stages. The discontinuous basement membrane in AG-73-treated explants may indicate an important role for this region in basement membrane assembly.

Animals↗
PubMed1998

Tissue transglutaminase is not increased during apoptosis of HT-1080 human fibrosarcoma cells.

Tissue transglutaminase (tTGase), a cytosolic enzyme which catalyzes the covalent cross-linking of proteins, is thought to be involved in the apoptosis. Here, we tested whether tTGase is involved during HT-1080 fibrosarcoma cell apoptosis induced by the YIGSR (Tyr-Ile-Gly-Ser-Arg) peptide. This sequence is derived from the laminin alpha1 chain, and its potency is increased by the formation of a 16mer polymerization using a lysine tree structure. Cells were treated with several different concentrations of Ac-Y 16 for 16 hours, and apoptosis was increased in dose-dependent manner. When assayed by incorporation of [14C] putrescine into succinylated casein, total transglutaminase activity was decreased in parallel with the change in the number of attached cells. Western blot analysis using polyclonal antibody against tTGase showed that the tTGase protein level had not been significantly changed when equal amounts of the protein were applied. To confirm this result, we induced apoptosis of these cells by coating the tissue culture plates with non-adhesive poly-hydroxyethyl methacrylate (HEMA). Western blot analysis showed that the tTGase protein level did not change during this process of apoptosis. Although it has been suggested that tTGase is involved in the process of apoptosis of various cells in vitro and in vivo, our data demonstrate that tTGase is not involved in the process of apoptosis of HT-1080 human fibrosarcoma cell induced by either Ac-Y 16 or a non-adhesive culture surface.

Apoptosis↗
PubMed1998

Growth and dissemination of a newly-established murine B-cell lymphoma cell line is inhibited by multimeric YIGSR peptide.

B-cell lymphoma frequently shows simultaneous dissemination to multiple organs. It also occasionally involves bone and causes osteolytic lesions. To study the mechanisms responsible for this capacity of lymphoma cells to grow in different tissue microenvironments and search for effective therapeutic interventions for this hematological malignancy, we established a new murine B-cell lymphoma cell line named MH-95. The tumor disseminated to multiple organs including the lung, liver, kidney, spleen and lymph nodes within 2 weeks after subcutaneous inoculation in nude mice. In addition, the tumor also grew in bone and caused osteoclastic osteolytic lesions. Thus, this tumor model mimics the behavior in many ways of B-cell lymphoma in humans. We studied the role of laminin, a major component of the basement membrane, in this model, since although it has been implicated in solid tumor metastasis, little is known about the involvement of laminin in the growth of B-cell lymphoma in bone and other organs. Immunohistochemical examination showed strong laminin expression in the stroma of the primary subcutaneous tumor and tumors in the bone and other organs. Systemic administration of the antagonistic laminin peptide YIGSR decreased primary tumor growth and tumor cell deposit in the bone, liver and kidney. In addition, the peptide also decreased apparent neovascularization in the tumor, suggesting that the peptide suppressed angiogenesis presumably due to inhibition of laminin binding to its receptors. These results demonstrate that the MH-95 B-cell lymphoma cells express laminin and suggest that laminin plays a critical role in the growth and simultaneous dissemination of tumor cells to multiple organs, similar to what has been described in solid tumors. The results also suggest that suppression of angiogenesis through interfering with laminin actions may be a useful adjuvant therapy for B-cell lymphoma.

Amino Acids, Diamino↗
PubMed1998

[Identification of biologically active sites in laminin an extracellular matrix protein].

Laminin-1, a major component of basement membranes, has multiple biological activities including promotion of cell adhesion, spreading, migration, growth, neurite outgrowth and tumor metastasis. Several active sites on laminin-1 have been identified previously. We modified these biologically active peptides to enhance their activities. The multimeric YIGSR (Tyr-Ile-Gly-Ser-Arg) peptides assembled on a branched lysine core were found to strongly enhance the activity of YIGSR in inhibiting tumor growth and metastasis. We also found the all-D-configuration peptide segment containing the IKVAV (Ile-Lys-Val-Ala-Val) sequence had similar biological activities to the native all-L-peptide in vitro and in vivo. These results suggest that these modified compounds are potentially useful for clinical applications. We have identified new active sequences from the laminin alpha 1 chain carboxyl-terminal globular domain (G domain). Using a systematic screening for cell binding sites with 113 overlapping synthetic peptides, we found five peptides (AG-10, AG-22, AG-32, AG-56, and AG-73) showed cell attachment activities with cell-type specificities. AG-10 and AG-32 were found to interact with integrins. AG-73 caused metastases of B16-F10 mouse melanoma cells to the liver colonization in mice. Additionally AG-73 was found to promote neurite outgrowth. Moreover, this peptide inhibited laminin mediated acinar-like development of a human submandibular gland cell line. The AG-73 domain on laminin-1 could be one of the most important biologically active sites. These active peptides may useful for study of the molecular mechanism of laminin-receptor interactions and for development of therapeutic reagents for tumor metastasis and angiogenasis.

Amino Acid Sequence↗
PubMed1997

Identification of cell binding sequences in mouse laminin gamma1 chain by systematic peptide screening.

Laminin-1, a major component of basement membranes, consists of three different chains designated alpha1, beta1, and gamma1 and has diverse biological functions. We have identified cell binding sites on the mouse laminin gamma1 chain, using systematic screening of 165 overlapping synthetic peptides covering the entire chain. We identified 12 cell binding sequences using HT-1080 human fibrosarcoma and B16-F10 mouse melanoma cells in two independent assays employing peptide-conjugated Sepharose beads and peptide-coated dishes. Four peptides (C-16, C-28, C-64, and C-68) located on the globular domains of the gamma1 chain were the most active and showed dose-dependent cell attachment. Cell attachment to C-68 was inhibited by EDTA and by anti-alpha2beta1 integrin antibodies. Cell attachment to C-16 and C-64 was partially inhibited by EDTA but was not inhibited by anti-integrin antibodies. EDTA and anti-integrin antibodies did not affect cell attachment to C-28. The four peptides were tested in adhesion and differentiation assays with endothelial, neuronal, and human salivary gland cells. C-16 was the most active for all of the cells, whereas the other three peptides showed cell type specificity in their activities. The active core sequences of C-16, C-28, C-64, and C-68 are YVRL, IRVTLN, TTVKYIFR, and SIKIRGTY, respectively. These sequences are highly conserved among the different species and in the laminin gamma2 chain. These results suggest that the specific sequences on the laminin gamma1 chain are biologically active and interact with distinct cell surface receptors.

Amino Acid Sequence↗
PubMed1997

Liver metastasis formation by laminin-1 peptide (LQVQLSIR)-adhesion selected B16-F10 melanoma cells.

Laminin-1, a major basement membrane glycoprotein, promotes tumor cell malignancy. Incubation of B16-F10 melanoma cells with a peptide containing an active sequence in laminin-1, designated AG-73 (leu-glu-val-glu-leu-ser-ile-arg; LQVQLSIR), enhances in vitro adhesion, migration, invasion and gelatinase production and in vivo lung colonization and metastases to the liver. In the current study, we have tried to define the mechanism of enhancement of liver metastases induced by AG-73 using B16-F10 murine melanoma cells selected for adhesion on AG-73-coated dishes. Cells were sequentially selected for adhesion more than 30 times and then characterized. AG-73 selected cells had much longer cytoplasmic processes and occasionally formed nodular aggregates. AG-73 selected cells attached 1.2- to 1.5-fold better to both AG-73 and laminin-1, were able to invade through the Matrigel-coated filter up to 6-fold more, grew s.c. 1.5-2 times faster, produced twice the number of lung colonies, and showed more liver nodules (12 of 28 vs. 1 of 27) than parental cells. Our data demonstrate that the enhanced malignant phenotype of B16-F10 cells can be observed in the absence of added peptide with the adhesion-selected cells.

Amino Acid Sequence↗
PubMed1997

Fibulin-2 binds to the short arms of laminin-5 and laminin-1 via conserved amino acid sequences.

Epithelial cell-specific laminin-5, consisting of three chains, alpha3, beta3, and gamma2, is a component of the anchoring filament that traverses the lamina lucida beneath the hemidesmosomes of epidermal cells and functions to link these cells to the basement membrane. We have studied the molecular interaction between laminin-5 and extracellular matrix proteins using recombinant proteins and synthetic peptides. Affinity chromatography assays with recombinant fragments of the laminin gamma2 short arm identified a 195-kDa binding protein in the conditioned media from the mouse epidermal cell line Pam 212 and from primary dermal fibroblasts. This molecule was identified by Western blotting as fibulin-2, a recently identified extracellular matrix protein. Using deletion mutants and various synthetic peptides in competition assays, the 9-amino acid sequence SADFSVHKI (residues 199-207) in domain IV of the gamma2 chain was defined as a critical site for fibulin-2 binding. An anti-gamma2 antibody co-immunoprecipitated fibulin-2 from the conditioned media, further confirming the interaction of fibulin-2 with laminin-5. Fibulin-2 was also found to interact with laminin-1 (alpha1beta1gamma1) through a region (residues 654-665) of the alpha1 chain short arm whose sequence is similar to that of the fibulin-2 binding site of the gamma2 chain. Together these results suggest that fibulin-2 functions to bridge laminin-1 and laminin-5 with other extracellular matrix proteins, providing a linkage between the cell surface and the basement membrane.

Amino Acid Sequence↗
PubMed1996

A mechanism for regulation of melanoma invasion. Ligation of alpha6beta1 integrin by laminin G peptides.

Invasion of LOX human melanoma cells involves extracellular matrix (ECM) degradation and formation of cell surface invadopodia. Here we show that the ligation of alpha6beta1 by two peptides derived from the COOH-terminal globular domain of laminin-1 alpha1 chain (laminin G peptides), designated AG-10 (NPWHSIYITRFG) and AG-32 (TWYKIAFQRNRK), and antibodies against alpha6 and beta1 integrins promoted invasiveness. AG-10 and AG-32 inhibited cell adhesion on laminin, and the antibodies blocked cell adhesion on immobilized AG-10 and AG-32, suggesting that the peptides interact primarily with alpha6beta1 integrin. These soluble peptides and integrin antibodies induced invasiveness by causing an 2-3-fold increase in ECM degradation and invadopodial activity independently of adhesion activity of integrins that were prebound to ECM. The induced ECM degradation and invasion was associated with an increased surface expression of the 170-kDa membrane-bound gelatinase, seprase, as well as its intense localization at invadopodia but not at focal adhesions. However, the total expression levels of seprase, gelatinase A and beta1 integrins were not altered. We suggest that laminin G peptides act on the alpha6beta1 integrin signaling of invasion by stimulating invadopodial activities, which is distinct from their direct effects on cell adhesion on immobilized ECM.

Amino Acid Sequence↗
PubMed1996

Active peptides from the carboxyl-terminal globular domain of laminin alpha2 and Drosophila alpha chains.

The laminin alpha1 chain carboxyl-terminal globular domain (G domain) contains multiple biological activities. Recently, we identified five cell binding sequences from the G domain by screening with overlapping 12-mer peptides encompassing the entire domain. The structures of these five sequences in the alpha1 chain are conserved in the corresponding regions of the different laminin alpha chains. Here we characterize the adhesion activities of the corresponding peptide segments from both the mouse laminin alpha2 chain and Drosophila laminin alpha chain using peptide-coated plastic plates and peptide-conjugated Sepharose beads. Using several cell lines, the laminin alpha2 chain peptides showed cell attachment and/or spreading activities with cell type specificities. Cell spreading on MG-10 was inhibited by integrin antibodies. Four of the Drosophila laminin peptides showed cell attachment activities. These results suggest that biologically active regions in the G domain are conserved in the laminin alpha1 and alpha2 chains, and that these regions in laminin play an important role in cell surface receptor interactions.

Amino Acid Sequence↗
PubMed1996

Identification of synthetic peptides derived from laminin alpha1 and alpha2 chains with cell type specificity for neurite outgrowth.

Laminin-1 is a potent promoter of neurite outgrowth. Here we find that the laminin-1 alpha chain contains peptide sequences that stimulate attachment and neurite outgrowth in some but not all neuronal cells. Testing of a series of overlapping peptides for biological activity with three laminin-1-responsive, neuronally derived cell lines resulted in the identification of peptide sequences, RKRLQVQLSIRT and KNRLTIELEVRT, from corresponding regions of the alpha1 and alpha2 (merosin) chain globular regions, respectively, that were active for attachment for all three cell lines and for neurite outgrowth with two of the cell lines. These data represent the identification of novel peptide sequences active with certain neuronal cells from the a1 and a2 chains of laminin. The peptides showed different attachment and neurite outgrowth activities depending on the cell type, suggesting cell type specificity in the response of the cells.

Amino Acid Sequence↗
PubMed1996

Conserved neuron promoting activity in Drosophila and vertebrate laminin alpha1.

Drosophila S2 cells were transfected with constructs that code for two portions of the Drosophila laminin alpha chain. Construct recalphaL coded for domains III, I/II, and G of laminin alpha. Construct recalphaS coded for only the COOH-most 12% of the I/II domain and the G domain. The corresponding polypeptides were isolated and characterized from the culture media. The recalphaL chain partly formed disulfide-linked heterotrimers with the endogenously produced beta and gamma laminin chains. Like normal Drosophila laminin, a substrate coating of either recalphaL or recalphaS supported neuron differentiation and neurite extension of primary Drosophila embryo cell cultures. However, at the same low concentrations, only Drosophila laminin-1, but neither recalphaL nor recalphaS supported myogenesis in these cultures. Previously, an overlapping set of dodecapeptides that covered a region of the murine laminin alpha1 chain similar to recalphaS had been synthesized and tested for cell culture support properties (Nomizu, M., Kim, W. H., Yamamura, K., Utani, A., Otaka, A., Roller, P. P., Kleinman, H. K., and Yamada, Y. (1995) J. Biol. Chem. 270, 20583-20590). The Drosophila laminin alpha homologues of the six most active vertebrate dodecapeptides were now synthesized and tested as substrates for differentiation of primary Drosophila embryo cells. Peptides that contained either the Drosophila sequence SIKVGV or the murine homologue, SIKVAV, provided support for neurite extension.

Amino Acid Sequence↗
PubMed1996

Mechanism of laminin chain assembly into a triple-stranded coiled-coil structure.

Laminin, a basement membrane glycoprotein, is a heterotrimer with alpha, beta, and gamma chains held together by a triple-stranded alpha-helical coiled-coil structure. Recently, a short peptide sequence at the C-terminus of the alpha-helical domain of each chain was identified as a critical site for the initiation of laminin chain assembly. Synthetic peptides, B1 and B2 (51-mers from the mouse laminin beta 1 and gamma 1 chains respectively) and M (55-mer from the laminin alpha 2 chain), containing these sites were able to assemble into a triple-stranded coiled-coil structure with chain-specific interactions [Nomizu, M., Otaka, A., Utani, A., Roller, P. P., & Yamada, Y. (1994) J. Biol. Chem. 269, 30386-30392]. Here we focus on the mechanism of laminin assembly and examine the conformation and stability of the peptides under various conditions using circular dichroism (CD) spectroscopy. Dependence on chain length for the conformation and stability of trimers suggests that 51-mers for laminin beta 1 and gamma 1 chains and a 55-mer for the laminin alpha 2 chain are critical to attain high thermal stability (T m = 62 degrees C), similar to the larger fragments (approximately 200-mers) and to intact laminins. Since the conformation and stability are dependent on pH and the B1 and B2 monomers and the B1-B2 dimer conformations are partially destroyed at neutral pH, it is likely that they contain intra- and/or interchain repulsions by acidic residues. Moreover, the B1-B2 dimer was significantly more stable under acidic conditions, while the B1-B2/M trimer appears to dissociate into separate B1-B2 and M peptides at pH 2. Urea-induced denaturation showed that the B1-B2/M was more stable than the B1-B2, while both complexes showed virtually identical guanidine hydrochloride denaturation curves. Our data indicate that ionic interactions between B1-B2 and M are critical for the specific trimer formation. We propose a mechanism for laminin assembly: (1) A heterodimer B1-B2 is preferentially formed and creates an acidic pocket which provides a less stable structure due to intra- and intermolecular repulsions between acidic amino acids. (2) A basic site in the M peptide interacts specifically with the acidic pocket of the B1-B2 dimer and results in assembly into a more stable triple-stranded coiled-coil structure.

Amino Acid Sequence↗
PubMed1996

Conformational analysis of cyclic hexapeptides designed as constrained ligands for the SH2 domain of the p85 subunit of phosphatidylinositol-3-OH kinase.

The structures of the cyclic hexapeptide cyclo(-Gly-Tyr-Val-Pro-Met-Leu-) (1) and its phosphotyrosyl (pTyr) derivative cyclo[-Gly-Tyr(PO3H2)-Val-Pro-Met-Leu-] (2), designed as constrained models of a sequence that interacts with the src homology 2 (SH2) region of the p85 subunit of phosphatidylinositol-3-OH kinase (PI-3 kinase), were studied in methanol/water solutions by 500 MHz nmr spectroscopy. Compound 1 was found to exist as a 2:1 mixture of isomers about the Val-Pro bond (trans and cis prolyl) between 292-330 K in 75% CD3O(D,H)/(D,H)2O solutions. A third species of undetermined structure (ca. 5%) was also observed. Compound 2, a model of phosphorylated peptide ligand that binds to the PI-3 kinase SH2 domain, exhibited similar conformational isomerism. When either compound was dissolved in pure solvent [i.e., 100% CD3O(H,D) or (H,D)2O] the ratio of cis to trans isomers was ca 1:1. A battery of one- and two-dimensional nmr experiments at different temperatures and solvent compositions allowed a complete assignment of both the cis and trans forms of 1 and indicated the trans compound to be the major isomer. The spectral properties of the phophorylated derivative 2 paralleled those of 1, indicating like conformations for the two compounds. Analysis of rotating frame Overhauser spectroscopy data, coupling constants, amide proton temperature dependence, and amide proton exchange rates generated a set of constraints that were employed in energy minimization and molecular dynamics calculations using the CHARMM force field. The trans isomer exists with the tyrosine and C-terminal Tyr(+3) (Met) residues at opposite corners of the 18-membered ring separated by a distance of 16-18 A, in contrast with the cis isomer where the side chains of these residues are much closer in space (7-14 A). It was previously shown that the pTyr and the third amino acid C-terminal to this residue are the critical recognition elements for pTyr-peptide binding to the PI-3 kinase SH2 domain. Such cyclic structures may offer appropriate scaffolding for positioning important amino acid side chains of pTyr-containing peptides as a means of increasing their binding affinities to SH2 domains, and in turn provide a conceptual approach toward the design of SH2 domain directed peptidomimetics.

Amino Acid Sequence↗
PubMed1996

Inhibition of angiogenesis, tumour growth and experimental metastasis of human fibrosarcoma cells HT1080 by a multimeric form of the laminin sequence Tyr-Ile-Gly-Ser-Arg (YIGSR).

A multimeric peptide, Ac-Y16, consisting of 16 YIGSR sequences from laminin was evaluated for its effect on experimental metastasis, angiogenesis and tumour growth of HT1080 human fibrosarcoma cells. Co-injection of 0.5 mg per mouse of Ac-Y16 i.v. with HT 1080 cells inhibited lung colonisation by 100%, whereas 0.5 mg per mouse of monomeric Ac-YIGSR-NH2(AcY1) inhibited by 94%. Ac-Y16 did not show any direct cytotoxicity in tumour cells in vivo. The effect of the peptides on angiogenesis and tumour growth respectively were evaluated by counting areas of neovessels and weighing tumours after the s.c. implantation of HT1080 cells with basement membrane extracts and the peptide into nude mice. Co-injection of 0.5 mg per mouse of AC-Y16 s.c. with HT1080 cells inhibited angiogenesis and tumour growth by 92% (P<0.05) and 76% (P<0.05) respectively, whereas 0.5 mg per mouse of monomeric Ac-YIGSR-NH2(Ac-Y1) inhibited angiogenesis and tumour growth by 40% (P<0.05) and 9% (P>0.05) respectively. It can be inferred from these data that anti-tumour effects of Ac-Y16 are likely to result from anti-angiogenesis. Intraperitoneal administration of Ac-Y16 was also effective in inhibiting angiogenesis, tumour growth and lung colonisation of HT1080 cells. It was concluded that the multimeric YIGSR-containing peptide, Ac-Y16, inhibits angiogenesis, tumour growth and experimental metastasis more than the monomeric form and that it is active when administered i.p., iv. and s.c.

Amino Acid Sequence↗
PubMed1995

The synthetic [Tyr5,12,Lys7]-polyphemusin II peptide (T22) binds to the CD4 cell surface molecule.

The [Tyr5,12,Lys7]-polyphemusin II peptide (T22) inhibits HIV-1 replication in lymphocytes. The mechanism of T22 inhibition of HIV-1 replication may involve T22 competition with HIV-1 for attachment sites on the plasma membrane of targeted cells. Here we find that the T22 peptide binds to the CD4 molecule in affinity columns. We also find that antiserum to CD4 inhibits cell attachment to T22. Further CD4+ transfected cells attach to T22 while their parental cells which do not express CD4 do not attach to T22. These data demonstrate that T22 binds to the CD4 molecule and supports the hypothesis that T22 inhibits HIV-1 replication by binding to the cell surface CD4 molecule and inhibiting uptake of the virus.

Amino Acid Sequence↗