The Ig VH complementarity-determining region 3-containing Rb9 peptide, inhibits melanoma cells migration and invasion by interactions with Hsp90 and an adhesion G-protein coupled receptor

The present work aims at investigating the mechanism of action of the Rb9 peptide, which contains the VHCDR 3 sequence of anti-sodium-dependent phosphate transport protein 2B (NaPi2B) monoclonal antibody RebMab200 and displayed antitumor properties. Short peptides corresponding to the hypervariable complementarity-determining regions (CDRs) of immunoglobulins have been associated with antimicrobial, antiviral, immunomodulatory and antitumor activities regardless of the specificity of the antibody. We have shown that the CDR derived peptide Rb9 induced substrate hyperadherence, inhibition of cell migration and matrix invasion in melanoma and other tumor cell lines. Rb9 also inhibited metastasis of murine melanoma in a syngeneic mouse model. We found that Rb9 binds to and interferes with Hsp90 chaperone activity causing attenuation of FAK-Src signaling and downregulation of active Rac1 in B16F10-Nex2 melanoma cells. The peptide also bound to an adhesion G-protein coupled receptor, triggering a concentration-dependent synthesis of cAMP and activation of PKA and VASP signaling as well as IP-3 dependent Ca2+ release. Hsp90 is highly expressed on the cell surface of melanoma cells, and synthetic agents that target Hsp90 are promising cancer therapeutic drugs. Based on their remarkable antitumor effects, the CDR-H3-derived peptides from RebMab200, and particularly the highly soluble and stable Rb9, are novel candidates to be further studied as potential antitumor drugs, selectively acting on cancer cell motility and invasion

AC-1001 H3 CDR peptide induces apoptosis and signs of autophagy in vitro and exhibits antimetastatic activity in a syngeneic melanoma model

Antibody-derived peptides modulate functions of the immune system and are a source of anti-infective and antitumor substances. Recent studies have shown that they comprise amino acid sequences of immunoglobulin complementarity-determining regions, but also fragments of constant regions. VH CDR3 of murine mAb AC-1001 displays antimetastatic activities using B16F10-Nex2 murine melanoma cells in a syngeneic model. The peptide was cytotoxic in vitro in murine and human melanoma cells inducing reactive oxygen species (ROS) and apoptosis by the intrinsic pathway. Signs of autophagy were also suggested by the increased expression of LC3/LC3II and Beclin 1 and by ultrastructural evidence. AC-1001 H3 bound to both G- and F-actin and inhibited tumor cell migration. These results are important evidence of the antitumor activity of Ig CDR-derived peptides. © 2016 Federation of European Biochemical Societies

Mastoparan induces apoptosis in B1 6F10-Nex2 melanoma cells via the intrinsic mitochondrial pathway and displays antitumor activity in vivo

Mastoparan is an a-helical and amphipathic tetradecapeptide obtained from the venom of the wasp Vespula lewisii. This peptide exhibits a wide variety of biological effects, including antimicrobial activity, increased histamine release from mast cells, induction of a potent mitochondrial permeability transition and tumor cell cytotoxicity. Here, the effects of mastoparan in malignant melanoma were studied using the murine model of B16F10-Nex2 cells. in vitro, mastoparan caused melanoma cell death by the mitochondrial apoptosis pathway, as evidenced by the Annexin V-FITC/PI assay, loss of mitochondrial membrane potential (Delta psi(m)), generation of reactive oxygen species, DNA degradation and cell death signaling. Most importantly, mastoparan reduced the growth of subcutaneous melanoma in syngeneic mice and increased their survival. the present results show that mastoparan induced caspase-dependent apoptosis in melanoma cells through the intrinsic mitochondrial pathway protecting the mice against tumor development. (C) 2014 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)INCT ToxConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Butantan Inst, Biochem & Biophys Lab, São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, Expt Oncol Unit UNONEX, São Paulo, SP, BrazilUniv São Paulo, Inst Biomed Sci, Dept Immunol, BR-05508 São Paulo, SP, BrazilUniv São Paulo, Cell & Mol Therapy Ctr NUCEL NETCEM, São Paulo, BrazilUniv São Paulo, Sch Med, Lab Genet & Mol Hematol LIM31, BR-05508 São Paulo, BrazilButantan Inst, Lab Genet, São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, Expt Oncol Unit UNONEX, São Paulo, SP, BrazilFAPESP: 2010/51077-5Web of Scienc

Jacaranone Induces Apoptosis in Melanoma Cells via ROS-Mediated Downregulation of Akt and p38 MAPK Activation and Displays Antitumor Activity in Vivo

Background: Malignant melanoma is a deadly type of metastatic skin cancer with increased incidence over the past 30 years. Despite the advanced knowledge on the biology, immunobiology and molecular genetics of melanoma, the alternatives of treatment are limited with poor prognosis. On clinical trials, natural products and among them redox-active quinones have been tested in the attempt to control the growth of cancer cells. Recently, we isolated jacaranone from Pentacalia desiderabilis, a benzoquinone derivative that showed a broad antitumor activity and protective anti-melanoma effect in a syngeneic model. the purified substance is active at micromolar concentrations, is not hemolytic, and is not toxic in naive mice.Methodology/Principal Findings: the jacaranone antitumor activity was shown against several human cancer cell lines in vitro. Moreover, the induction of apoptosis in murine melanoma cells and jacaranone antitumor activity in vivo, in a melanoma experimental model, were also shown. Jacaranone renders antiproliferative and proapoptotic responses in tumor cells, by acting on Akt and p38 MAPK signaling pathways through generation of reactive oxygen species (ROS). the free radical scavenger N-acetyl-cysteine (NAC) was able to completely suppress cell death induced by jacaranone as it blocked Akt downregulation, p38 MAPK activation as well as upregulation of proapoptotic Bax. Notably, treatment of melanoma growing subcutaneously in mice with jacaranone significantly extended the mean survival times in a dose-dependent manner.Conclusions/Significance: the results provide evidence for the mechanisms of action of jacaranone and emphasize the potential use of this quinone for the treatment of melanoma

Pyrostegia venusta heptane extract containing saturated aliphatic hydrocarbons induces apoptosis on B16F10-Nex2 melanoma cells and displays antitumor activity in vivo

Background: Pyrostegia venusta (Ker. Gawl.) Miers (Bignoniacea) is a medicinal plant from the Brazilian Cerrado used to treat leucoderma and common diseases of the respiratory system. Objective: To investigate the antitumor activity of P.venusta extracts against melanoma. Materials and Methods: The cytotoxic activity and tumor induced cell death of heptane extract (HE) from P. venusta flowers was evaluated against murine melanoma B16F10-Nex2 cells in vitro and in a syngeneic model in vivo. Results: We found that HE induced apoptosis in melanoma cells by disruption of the mitochondrial membrane potential, induction of reactive oxygen species and late apoptosis evidenced by plasma membrane blebbing, cell shrinkage, chromatin condensation and DNA fragmentation, exposure of phosphatidylserine on the cell surface and activation of caspase-2,-3,-8,-9. HE was also protective against singeneyc subcutaneous melanoma HE compounds were also able to induce cell cycle arrest at G2/M phases on tumor cells. On fractionation of HE in silica gel we isolated a cytotoxic fraction that contained a mixture of saturated hydrocarbons identified by (1) H NMR and GC-MS analyses. Predominant species were octacosane (C 28 H 58 -36%) and triacontane (C 30 H 62 -13%), which individually showed significant cytotoxic activity against murine melanoma B16F10-Nex2 cells in vitro and a very promising antitumor protection against subcutaneous melanoma in vivo. Conclusion: The results suggest that the components of the heptane extract, mainly octasane and triacontane, which showed antitumor properties in experimental melanoma upon regional administration, might also be therapeutic in human cancer, such as in the mostly epidermal and slowly invasive melanomas, such as acral lentiginous melanoma, as an adjuvant treatment to surgical excision.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Chemical structure of jacaranone isolated from leaves of <i>P. </i><i>desiderabilis</i><i>.</i>

<p>Chemical structure of jacaranone isolated from leaves of <i>P. </i><i>desiderabilis</i><i>.</i></p