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Tumor targeting by Michele Bernasconi

Schweizer Krebsbulletin, 2019

Rhabdomyosarcoma (RMS) is the most common childhood soft tissue sarcoma. Current therapies need t... more Rhabdomyosarcoma (RMS) is the most common childhood soft tissue sarcoma. Current therapies need to be improved in order to increase survival, and decrease long-term side effects. We are currently following two approaches to devise novel targeted therapies: development of targeted nanotherapeutics, and identification of novel targets for chimeric antigen (CAR) T cell therapies.

Journal of Materials Chemistry B, 2017

Important elements for an efficient tumor targeted delivery are cancer-specific de novo-or over-e... more Important elements for an efficient tumor targeted delivery are cancer-specific de novo-or over-expression of target receptors and their availability on the tumor cell surface. Peptides can be designed to selectively bind to such receptors and act as tumor-targeting ligands, as has been revealed in several preclinical studies. Notably, the amino acid sequences of these peptides can be chemically modified to prevent enzymatic degradation and improve the stability of the peptide. Furthermore, tumor-targeting peptides can be conjugated to the surface of nanosized drug carriers for the selective delivery of anticancer drugs to tumors. In this review, tumor receptors for which targeting peptides have been identified are described, and their targeting potential is considered. Various chemical modifications of peptides are thoroughly described, and targeting peptides as well as peptide-functionalized nanocarriers are critically discussed. The limitations of active targeting nanocarriers are evaluated in detail, and an outlook on the potential of tumor-targeting peptides and their clinical applications is provided.

Nanomedicine, 2017

Aim: Our goal was to improve vincristine (VCR) based rhabdomyosarcoma (RMS) therapy by encapsulat... more Aim: Our goal was to improve vincristine (VCR) based rhabdomyosarcoma (RMS) therapy by encapsulating the drug into liposomes. A targeting strategy was attempted to enhance tumor accumulation. Materials & methods: VCR was loaded in control and peptide-decorated liposomes via an active method. The interaction of an RMS-specific peptide with the presumed target furin and the cellular uptake of both liposomal groups were studied in vitro. Pharmacokinetics and biodistribution of VCR-containing liposomes were assessed in an RMS xenograft mouse model. Results: Liposomes ensured high VCR concentration in plasma and in the tumor. Peptide-decorated liposomes showed modest uptake in RMS cells. Conclusion: The investigated peptide-modified liposomal formulation may not be optimal for furin-mediated RMS targeting. Nevertheless, VCR-loaded liposomes could serve as a delivery platform for experimental RMS.

PLOS One, 2010

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Improvement of treatme... more Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Improvement of treatment efficacy and decreased side effects through tumor-targeted drug delivery would be desirable. By panning with a phage-displayed cyclic random peptide library we selected a peptide with strong affinity for RMS in vitro and in vivo. The peptide minimal binding motif Arg-X-(Arg/Lys)(Arg/Lys) identified by alanine-scan, suggested the target receptor to be a proprotein convertase (PC). Expression profiling of all PCs in RMS biopsies and cell lines revealed consistent high expression levels for the membranebound furin and PC7. Direct binding of RMS-P3 peptide to furin was demonstrated by affinity chromatography and supported by activity and colocalization studies. Treatment of RMS in mice with doxorubicin coupled to the targeting peptide resulted in a two-fold increase in therapeutic efficacy compared to doxorubicin treatment alone. Our findings indicate surface-furin binding as novel mechanism for therapeutic cell penetration which needs to be further investigated. Furthermore, this work demonstrates that specific targeting of membrane-bound furin in tumors is possible for and suggests that RMS and other tumors might benefit from proprotein convertases targeted drug delivery. Citation: Hajdin K, D'Alessandro V, Niggli FK, Schäfer BW, Bernasconi M (2010) Furin Targeted Drug Delivery for Treatment of Rhabdomyosarcoma in a Mouse Model. PLoS ONE 5(5): e10445.

International Journal of Cancer, 2009

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. To improve existing th... more Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. To improve existing therapies and broaden the spectrum of cytotoxic agents that can be used in RMS treatment, we performed a phage-display-based screening for peptides that bind specifically to RMS cells. Two peptides binding to RMS and to other tumour cell lines, but not to normal skeletal muscle cells and fibroblasts, were isolated from phage-displayed random peptide libraries. One peptide, named RMS-I (CQQSNRGDRKRC) contained the integrin-binding motif RGD and its binding was blocked by an antibody against a v b 3 integrin, which is expressed on the RMS cell line RD. The isolation of RMS-I confirmed the validity of our screening procedure. The second peptide, named RMS-II (CMGNKRSAKRPC), shows sequence similarity to a previously identified peptide with tumour lymphatic specificity, LyP-1. However, RMS-II binds in vivo to RMS xenografts better than LyP-1 and homes to the tumour blood and not to lymphatic vessels. Therefore, RMS-II represents a promising peptide for the development of RMS-specific targeting approaches.

Cancer Cell, 2003

The vasculature in the angiogenic stages of a mouse model of pancreatic islet carcinogenesis was ... more The vasculature in the angiogenic stages of a mouse model of pancreatic islet carcinogenesis was profiled in vivo with phage libraries that display short peptides. We characterized seven peptides distinguished by their differential homing to angiogenic progenitors, solid tumors, or both. None homed appreciably to normal pancreatic islets or other organs. Five peptides selectively homed to neoplastic lesions in the pancreas and not to islet ␤ cell tumors growing subcutaneously, xenotransplant tumors from a human cancer cell line, or an endogenously arising squamous cell tumor of the skin. Three peptides with distinctive homing to angiogenic islets, tumors, or both colocalized with markers that identify endothelial cells or pericytes. One peptide is homologous with pro-PDGF-B, which is expressed in endothelial cells, while its receptor is expressed in pericytes.

Proceedings of the National Academy of Sciences, 2002

We used a screening procedure to identify protein domains from phage-displayed cDNA libraries tha... more We used a screening procedure to identify protein domains from phage-displayed cDNA libraries that bind both to bone marrow endothelial progenitor cells and tumor vasculature. Screening phage for binding of progenitor cell-enriched bone marrow cells in vitro, and for homing to HL-60 human leukemia cell xenograft tumors in vivo, yielded a cDNA fragment that encodes an Nterminal fragment of human high mobility group protein 2 (HMGN2, formerly HMG-17). Upon i.v. injection, phage displaying this HMGN2 fragment homed to HL-60 and MDA-MB-435 tumors.

Proceedings of the National Academy of Sciences, 2002

Organ specific drug targeting was explored in mice as a possible alternative to surgery to treat ... more Organ specific drug targeting was explored in mice as a possible alternative to surgery to treat prostate diseases. Peptides that specifically recognize the vasculature in the prostate were identified from phage-displayed peptide libraries by selecting for phage capable of homing into the prostate after an i.v. injection. One of the phage selected in this manner homed to the prostate 10 -15 times more than to other organs. Unselected phage did not show this preference. The phage bound also to vasculature in the human prostate. The peptide displayed by the prostate-homing phage, SMSIARL (single letter code), was synthesized and shown to inhibit the homing of the phage when co-injected into mice with the phage. Systemic treatment of mice with a chimeric peptide consisting of the SMSIARL homing peptide, linked to a proapoptotic peptide that disrupts mitochondrial membranes, caused tissue destruction in the prostate, but not in other organs. The chimeric peptide delayed the development of the cancers in prostate cancerprone transgenic mice (TRAMP mice). These results suggest that it may be possible to develop an alternative to surgical prostate resection and that such a treatment may also reduce future cancer risk.

Proceedings of the National Academy of Sciences, 1996

The expression of a number of human paired box-containing (PAX) genes has been correlated with va... more The expression of a number of human paired box-containing (PAX) genes has been correlated with various types of tumors. Novel fusion genes encoding chimeric fusion proteins have been found in the pediatric malignant tumor alveolar rhabdomyosarcoma (RMS). They are generated by two chromosomal translocations t(2;13) and t(1;13) juxtaposing PAX3 or PAX7, respectively, with a forkhead domain gene FKHR. Here we describe that specific down-regulation of the t(2;13) translocation product in alveolar RMS cells by antisense oligonucleotides results in reduced cellular viability. Cells of embryonal RMS, the other major histiotype of this tumor, were found to express either wild type PAX3 or PAX7 at elevated levels when compared with primary human myoblasts. Treatment of corresponding embryonal RMS cells with antisense olignucleotides directed against the mRNA translational start site of either one of these two transcription factors similarly triggers cell death, which is most likely due to induction of apoptosis. Retroviral mediated ectopic expression of mouse Pax3 in a PAX7 expressing embryonal RMS cell line could partially rescue antisense induced apoptosis. These data suggest that the PAX3͞FKHR fusion gene and wild-type PAX genes play a causative role in the formation of RMS and presumably other tumor types, possibly by suppressing the apoptotic program that would normally eliminate these cells.

Nucleic Acids Research, 1994

Furin in rhabdomyosarcoma by Michele Bernasconi

International Journal of Cancer, 2017

Proprotein convertases are proteases that have been implicated in the activation of a wide variet... more Proprotein convertases are proteases that have been implicated in the activation of a wide variety of proteins. These proteins are generally synthesised as precursor proteins and require limited proteolysis for conversion into their mature bioactive counterparts. Many of these proteins, including metalloproteases, growth factors and their receptors or adhesion molecules, have been shown to facilitate tumour formation and progression. Hence, this review will focus on the proprotein convertase furin and its role in cancer. The expression of furin has been confirmed in a large spectrum of cancers such as head and neck squamous cell carcinoma, breast cancer and rhabdomyosarcoma. Functional studies modulating furin activity uncovered its importance for the processing of many cancer-related substrates and strongly indicate that high furin activity promotes the malignant phenotype of cancer cells. In this review, we summarise the expression and function of furin in different cancer types, discuss its role in processing cancer-related proproteins and give examples of potential therapeutic approaches that take advantage of the proteolytic activity of furin in cancer cells.

PLOS ONE, 2016

The proprotein convertase (PC) furin cleaves precursor proteins, an important step in the activat... more The proprotein convertase (PC) furin cleaves precursor proteins, an important step in the activation of many cancer-associated proteins. Substrates of furin and furin-like PCs play a role in proliferation, metastasis and invasion. Some of them are involved in the progression of the pediatric soft tissue sarcoma rhabdomyosarcoma (RMS). In this study, we show that PCs, and in particular furin, are expressed in RMS cell lines. To investigate the functional role of furin, we generated RMS cell lines with modulated furin activity. Silencing or stable inhibition of furin delayed tumor growth in Rh30 and RD xenografts in vivo, and was correlated with lower microvessel density. Reduced furin activity also decreased migration and invasion abilities in vitro, and inhibition of furin in RMS cells diminished processing of IGF1R, VEGF-C, PDGF-B and MT1-MMP, leading to lower levels of mature proteins. Furthermore , we found that furin activity is required for proper IGF signaling in RMS cells, as furin silencing resulted in reduced phosphorylation of Akt upon IGF1 stimulation. Taken together, our results suggest that furin plays an important role in the malignant phenotype of RMS cells by activating proteins involved in tumor growth and vascularization, metastasis and invasion.

EBV by Michele Bernasconi

PloS one, 2015

Molecular Cancer, 2007

Epigenetic silencing of regulatory genes by aberrant methylation contributes to tumorigenesis. DN... more Epigenetic silencing of regulatory genes by aberrant methylation contributes to tumorigenesis. DNA methyltransferase inhibitors (DNMTI) represent promising new drugs for anti-cancer therapies. The DNMTI 5-Azacytidine is effective against myelodysplastic syndrome, but induces switching of latent to lytic Epstein-Barr virus (EBV) in vitro and results in EBV DNA demethylation with the potential of induction of lytic EBV in vivo. This is

Cellular Microbiology, 2007

or adults with mature immune systems. Infectious mononucleosis and chronic immune activation are ... more or adults with mature immune systems. Infectious mononucleosis and chronic immune activation are linked to increased risk for EBV-associated lymphoma. Here we show that EBV initiates progressive lytic infection by expression of BZLF-1 and the late lytic genes gp85 and gp350/220 in cord blood mononuclear

Journal of General Virology, 2007

Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) blocks B-cell receptor (BCR) signalli... more Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) blocks B-cell receptor (BCR) signalling after BCR cross-linking to inhibit activation of lytic EBV, and ectopically expressed LMP2B negatively regulates LMP2A. Here, it is demonstrated that silencing of LMP2B in EBV-harbouring Burkitt's lymphoma Akata cells results in reduced expression of EBV immediateearly lytic BZLF1 gene mRNA and late lytic gp350/220 protein upon BCR cross-linking. Similarly, reduction of lytic EBV activation was observed in Akata cells overexpressing LMP2A. In contrast, silencing of LMP2A expression resulted in higher lytic EBV mRNA and protein expression in BCR cross-linked Akata cells. These observations indicate a role for LMP2B distinct from that of LMP2A in regulation of lytic EBV activation in the host cell and support the hypothesis that LMP2B exhibits a negative-regulatory effect on the ability of LMP2A to maintain EBV latency by preventing the switch to lytic replication. 2007). Nevertheless, the role of LMP2B in the presence of EBV remains unknown.

Journal of Infectious Diseases, 2014

Epstein-Barr virus (EBV) infects more than 90% of the human population within the first two decad... more Epstein-Barr virus (EBV) infects more than 90% of the human population within the first two decades of life and establishes reversible latent infection in B cells. Which stimuli leads to switching from latent to lytic EBV infection in vivo are still elusive. Group A Streptococci (GAS) are a common cause of bacterial pharyngotonsillitis in children and adolescents and colonize tonsil and pharynx of up to 20% of healthy children. Thus, concomitant

Schweizer Krebsbulletin, 2019

Journal of Materials Chemistry B, 2017

Nanomedicine, 2017

PLOS One, 2010

International Journal of Cancer, 2009

Cancer Cell, 2003

Proceedings of the National Academy of Sciences, 2002

Proceedings of the National Academy of Sciences, 1996

Nucleic Acids Research, 1994

International Journal of Cancer, 2017

PLOS ONE, 2016

PloS one, 2015

Molecular Cancer, 2007

Cellular Microbiology, 2007

Journal of General Virology, 2007

Journal of Infectious Diseases, 2014

Journal of Virology, 2008

EBV has not been established. Here, LMP2B, LMP2A, or both were overexpressed in EBV-harboring Aka... more EBV has not been established. Here, LMP2B, LMP2A, or both were overexpressed in EBV-harboring Akata cells to study the function of LMP2B. The overexpression of LMP2B increased the magnitude of EBV switching from its latent to its lytic form upon BCR cross-linking, as indicated by a more-enhanced upregulation and expression of EBV lytic genes and significantly increased production of transforming EBV compared to Akata vector control cells or LMP2Aoverexpressing cells. Moreover, LMP2B lowered the degree of BCR cross-linking required to induce lytic EBV infection. Finally, LMP2B colocalized with LMP2A as demonstrated by immunoprecipitation and immunofluorescence and restored calcium mobilization upon BCR cross-linking, a signaling process inhibited by LMP2A. Thus, our findings suggest that LMP2B negatively regulates the function of LMP2A in preventing the switch from latent to lytic EBV replication.

Journal of Virology, 2008

paralleled by lower proliferation rates. In summary, these data suggest that EBV exploits the B-c... more paralleled by lower proliferation rates. In summary, these data suggest that EBV exploits the B-cell differentiation status and tissue origin to establish persistent infection.

Journal of Virology, 2010

Virology journal, 2006

The Epstein-Barr virus (EBV) is associated with lymphoid malignancies, including Burkitt's ly... more The Epstein-Barr virus (EBV) is associated with lymphoid malignancies, including Burkitt's lymphoma (BL), and can transform human B cells in vitro. EBV-harboring cell lines are widely used to investigate lymphocyte transformation and oncogenesis. Qualitative EBV gene expression has been extensively described, but knowledge of quantitative transcription is lacking. We hypothesized that transcription levels of EBNA1, the gene essential for EBV persistence within an infected cell, are similar in BL cell lines. To compare quantitative gene transcription in the BL cell lines Namalwa, Raji, Akata, Jijoye, and P3HR1, we developed an oligonucleotide microarray chip, including 17 housekeeping genes, six latent EBV genes (EBNA1, EBNA2, EBNA3A, EBNA3C, LMP1, LMP2), and four lytic EBV genes (BZLF1, BXLF2, BKRF2, BZLF2), and used the cell line B95.8 as a reference for EBV gene transcription. Quantitative polymerase chain reaction assays were used to validate microarray results. We found that...

Journal of virology, 2014

In order to understand and possibly treat B-cell malignancies associated with latent gammaherpesv... more In order to understand and possibly treat B-cell malignancies associated with latent gammaherpesvirus infection, it is vital to understand the factors that control the balance between the two transcriptional states of gammaherpesviruses: latency and lytic replication. We used murine gammaherpesvirus 68 (MHV 68) as a model system to investigate how engagement of endosomal Toll-like receptors (TLRs) impacts reactivation from latency in vitro and establishment of latent infection in vivo. We found that treatment with TLR7 ligand R848 or TLR9 ligand CpG oligodeoxynucleotide (ODN) suppresses reactivation of MHV 68 in vitro. These suppressive effects correlated with the ability to activate cellular transcription factor NF-κB. Downregulation of TLR9 by RNA interference in vitro led to a reduction of nuclear levels of NF-κB p65 and consequently to an increase of spontaneous reactivation in cells latently infected with MHV 68, indicating that the TLR9 pathway suppresses spontaneous reactivat...

International Journal of Cancer, 2013

Lymphoproliferative diseases (LPDs) associated with Epstein-Barr virus (EBV) infection cause sign... more Lymphoproliferative diseases (LPDs) associated with Epstein-Barr virus (EBV) infection cause significant morbidity and mortality in bone marrow and solid organ transplant recipients. To gain insight into LPD pathogenesis and to identify potential effective therapeutic approaches, we investigated early molecular events leading to B-cell transformation by gene expression profiling of EBV-infected B-cells from tonsils by Affymetrix microarray 72 hr postinfection when the B-cells hyperproliferation phase starts. Cell cycle and apoptosis were the most significantly affected pathways and enriched gene sets. In particular, we found significantly increased expression of cyclin-dependent kinase (CDK)1 and CCNB1 (cyclin B1) and of one of their downstream targets BIRC5 (survivin). Importantly, the strong upregulation of the antiapoptotic protein survivin was confirmed in lymphoblastoid cell lines (LCLs) and 71% of EBV-positive post-transplant EBV-LPD lesions scored positive for survivin. The validity of early transforming events for the identification of therapeutic targets for EBV-LPD was confirmed by the marked antiproliferative effect of the CDK inhibitor flavopiridol on LCLs and by the strong induction of apoptosis by survivin inhibition with YM155 or terameprocol. Our results suggest that targeting of CDKs and/or survivin in post-transplant EBV-LPD by specific inhibitors might be an important approach to control and eliminate EBV-transformed B-cells that should be further considered.

Trends in Microbiology, 2008

The oncogenic Epstein-Barr virus (EBV) infects the majority of the human population without doing... more The oncogenic Epstein-Barr virus (EBV) infects the majority of the human population without doing harm and establishes a latent infection in the memory B-cell compartment. To accomplish this, EBV hijacks B-cell differentiation pathways and uses its own viral genes to interfere with B-cell signalling to achieve life-long persistence. EBV latent membrane protein 2A (LMP2A) provides a surrogate B-cell receptor signal essential for cell survival and is believed to have a crucial role in the maintenance of latency by blocking B-cell activation which would otherwise lead to lytic EBV infection. These two functions demand tight control of LMP2A activity and expression levels. Based on recent insights in the function of LMP2B, an isoform of LMP2A, we propose a model for how LMP2B modulates the activity of LMP2A contributing to maintenance of EBV latency.

Journal of Experimental & Clinical Cancer Research

Background Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood, whose prog... more Background Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood, whose prognosis is still poor especially for metastatic, high-grade, and relapsed RMS. New treatments are urgently needed, especially systemic therapies. Chimeric Antigen Receptor T cells (CAR Ts) are very effective against hematological malignancies, but their efficacy against solid tumors needs to be improved. CD276 (B7-H3) is a target upregulated in RMS and detected at low levels in normal tissues. FGFR4 is a very specific target for RMS. Here, we optimized CAR Ts for these two targets, alone or in combination, and tested their anti-tumor activity in vitro and in vivo. Methods Four different single-domain antibodies were used to select the most specific FGFR4-CAR construct. RMS cell killing and cytokine production by CD276- and FGFR4-CAR Ts expressing CD8α or CD28 HD/TM domains in combination with 4-1BB and/or CD28 co-stimulatory domains were tested in vitro. The most effective CD276- and FGFR4...

PLOS ONE, 2017

Burkitt's lymphoma (BL) is the most common childhood cancer in equatorial Africa, and is endemic ... more Burkitt's lymphoma (BL) is the most common childhood cancer in equatorial Africa, and is endemic to areas where people are chronically co-infected with Epstein-Barr virus (EBV) and the malaria pathogen Plasmodium falciparum. The contribution of these pathogens in the oncogenic process remains poorly understood. We showed earlier that the activation of Toll-like receptor (TLR) 9 by hemozoin, a disposal product formed from the digestion of blood by P. falciparum, suppresses the lytic reactivation of EBV in BL cells. EBV lytic reactivation is regulated by the expression of transcription factor Zta (ZEBRA), encoded by the EBV gene BZLF1. Here, we explore in the BL cell line Akata, the mechanism involved in repression by TLR9 of expression of BZLF1. We show that BZLF1 repression is mediated upon TLR9 engagement by a mechanism that is largely independent of de novo protein synthesis. By CRISPR/Cas9-induced inactivation of TLR9, MyD88, IRAK4 and IRAK1 we confirm that BZLF1 repression is dependent on functional TLR9 and MyD88 signaling, and identify IRAK4 as an essential element for TLR9-induced repression of BZLF1 expression upon BCR cross-linking. Our results unprecedentedly show that TLR9-mediated inhibition of lytic EBV is largely independent of new protein synthesis and demonstrate the central roles of MyD88 and IRAK4 in this process contributing to EBV's persistence in the host's Bcell pool.

Cell Death & Disease, 2012

Photodiagnosis and Photodynamic Therapy, Mar 1, 2023

PLOS ONE, Aug 22, 2016

The proprotein convertase (PC) furin cleaves precursor proteins, an important step in the activat... more The proprotein convertase (PC) furin cleaves precursor proteins, an important step in the activation of many cancer-associated proteins. Substrates of furin and furin-like PCs play a role in proliferation, metastasis and invasion. Some of them are involved in the progression of the pediatric soft tissue sarcoma rhabdomyosarcoma (RMS). In this study, we show that PCs, and in particular furin, are expressed in RMS cell lines. To investigate the functional role of furin, we generated RMS cell lines with modulated furin activity. Silencing or stable inhibition of furin delayed tumor growth in Rh30 and RD xenografts in vivo, and was correlated with lower microvessel density. Reduced furin activity also decreased migration and invasion abilities in vitro, and inhibition of furin in RMS cells diminished processing of IGF1R, VEGF-C, PDGF-B and MT1-MMP, leading to lower levels of mature proteins. Furthermore, we found that furin activity is required for proper IGF signaling in RMS cells, as furin silencing resulted in reduced phosphorylation of Akt upon IGF1 stimulation. Taken together, our results suggest that furin plays an important role in the malignant phenotype of RMS cells by activating proteins involved in tumor growth and vascularization, metastasis and invasion.

Virology Journal, Jun 6, 2006

Journal of Materials Chemistry B, 2017

This review outlines the most recent advances in peptide-mediated tumor-targeting and gives insig... more This review outlines the most recent advances in peptide-mediated tumor-targeting and gives insight into the direction of the field.

Cancers, Oct 14, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Proceedings of the National Academy of Sciences of the United States of America, Feb 5, 2002

Organ specific drug targeting was explored in mice as a possible alternative to surgery to treat ... more Organ specific drug targeting was explored in mice as a possible alternative to surgery to treat prostate diseases. Peptides that specifically recognize the vasculature in the prostate were identified from phage-displayed peptide libraries by selecting for phage capable of homing into the prostate after an i.v. injection. One of the phage selected in this manner homed to the prostate 10-15 times more than to other organs. Unselected phage did not show this preference. The phage bound also to vasculature in the human prostate. The peptide displayed by the prostate-homing phage, SMSIARL (single letter code), was synthesized and shown to inhibit the homing of the phage when co-injected into mice with the phage. Systemic treatment of mice with a chimeric peptide consisting of the SMSIARL homing peptide, linked to a proapoptotic peptide that disrupts mitochondrial membranes, caused tissue destruction in the prostate, but not in other organs. The chimeric peptide delayed the development of the cancers in prostate cancerprone transgenic mice (TRAMP mice). These results suggest that it may be possible to develop an alternative to surgical prostate resection and that such a treatment may also reduce future cancer risk.

International Journal of Molecular Sciences, Jan 30, 2023

PLOS ONE, Apr 9, 2015

<p>Infection of AGS-EV (empty vector control), AGS-hT (hTERT-overexpression) and AGS-DN (DN... more <p>Infection of AGS-EV (empty vector control), AGS-hT (hTERT-overexpression) and AGS-DN (DNhTERT-overexpression) cells was confirmed by EBER-FISH 3 (A), 7 (B) and 14 (C) dpi. Nuclei are stained with DAPI (blue). GFP expressing cells appear green, EBER expressing cells appear red and double positive cells appear with yellow nuclei in merged pictures. Pictures shown are representative for three independent experiments; Scale bar = 50 μm.</p

PLOS ONE, Apr 9, 2015

The Epstein-Barr virus (EBV) is transmitted from host-to-host via saliva and is associated with e... more The Epstein-Barr virus (EBV) is transmitted from host-to-host via saliva and is associated with epithelial malignancies including nasopharyngeal carcinoma (NPC) and some forms of gastric carcinoma (GC). Nevertheless, EBV does not transform epithelial cells in vitro where it is rapidly lost from infected primary epithelial cells or epithelial tumor cells. Longterm infection by EBV, however, can be established in hTERT-immortalized nasopharyngeal epithelial cells. Here, we hypothesized that increased telomerase activity in epithelial cells enhances their susceptibility to infection by EBV. Using HONE-1, AGS and HEK293 cells we generated epithelial model cell lines with increased or suppressed telomerase activity by stable ectopic expression of hTERT or of a catalytically inactive, dominant negative hTERT mutant. Infection experiments with recombinant prototypic EBV (rB95.8), recombinant NPC EBV (rM81) with increased epithelial cell tropism compared to B95.8, or recombinant B95.8 EBV with BZLF1-knockout that is not able to undergo lytic replication, revealed that infection frequencies positively correlate with telomerase activity in AGS cells but also partly depend on the cellular background. AGS cells with increased telomerase activity showed increased expression mainly of latent EBV genes, suggesting that increased telomerase activity directly acts on the EBV infection of epithelial cells by facilitating latent EBV gene expression early upon virus inoculation. Thus, our results indicate that infection of epithelial cells by EBV is a very selective process involving, among others, telomerase activity and cellular background to allow for optimized host-to-host transmission via saliva.

Biomaterials Science, 2020

Recently, we described porphyrin-based periodic mesoporous organosilica (PMO) nanoparticles synth... more Recently, we described porphyrin-based periodic mesoporous organosilica (PMO) nanoparticles synthesized from a large functional octatriethoxysilylated porphyrin precursor. The framework of the nanoparticles was formed by J-aggregates of porphyrins allowing two-photon excitation photodynamic therapy (TPE-PDT) and NIR imaging. In the present work, these PMO were grafted with polyethylene glycol (PEG) moieties and an analogue of mannose 6-phosphate functionalized on anomeric position (AMFA). AMFA are known to efficiently target mannose 6-phosphate receptors (M6PR) which are over-expressed in various cancer cell lines (breast, prostate). Here, we demonstrated that M6PR was also over-expressed in rhabdomyosarcoma cells (RMS) and could be efficiently targeted with PMO-AMFA allowing TPE imaging and TPE-PDT of RMS cells. Furthermore the same treatment did not affect healthy myoblasts which do not over-express M6PR suggesting a specificity in its biomedical action.

Oncogene, May 31, 2010

Endemic Burkitt's lymphoma (BL) is considered to preferentially develop in equatorial Africa beca... more Endemic Burkitt's lymphoma (BL) is considered to preferentially develop in equatorial Africa because of chronic co-infection with Epstein-Barr virus (EBV) and the malaria pathogen Plasmodium falciparum. The interaction and contribution of both pathogens in the oncogenic process are poorly understood. Earlier, we showed that immune activation with a synthetic Toll-like receptor 9 (TLR9) ligand suppresses the initiation of EBV lytic replication in primary human B cells. In this study we investigate the mechanism involved in the suppression of EBV lytic gene expression in BL cell lines. We show that this suppression is dependent on functional TLR9 and MyD88 signaling but independent of downstream signaling elements, including phosphatidylinositol-3 kinase, mitogen-activated protein kinases and nuclear factor-jB. We identified TLR9 triggering resulting in histone modifications to negatively affect the activation of the promoter of EBV's master regulatory lytic gene BZLF1. Finally, we show that P. falciparum hemozoin, a natural TLR9 ligand, suppresses induction of EBV lytic gene expression in a dose-dependent manner. Thus, we provide evidence for a possible interaction between P. falciparum and EBV at the B-cell level and the mechanism involved in suppressing lytic and thereby reinforcing latent EBV that has unique oncogenic potential.

Cancer Cell, Nov 1, 2003

Cancers, Nov 10, 2020

Rhabdomyosarcoma (RMS) accounts for more than 50% of all soft tissue sarcomas in childhood and ad... more Rhabdomyosarcoma (RMS) accounts for more than 50% of all soft tissue sarcomas in childhood and adolescence. Despite progress and intensified multimodality treatment, prognoses are extremely poor with an overall survival rate of approximately 20% in the advanced stage. Therefore, there is an urgent need for targeted treatment options to improve overall survival rates, and to limit long-term side effects. The fibroblast growth factor receptor 4 (FGFR4) is overexpressed in RMS and other tumors as well. The goal of this work was to select FGFR4 specific single-domain antibodies (sdAb) and to develop FGFR4-targeted therapies. We could show that FGFR4-targeted liposomes have the potential to deliver drugs specifically to FGFR4-positive tumor cells and that chimeric antigen receptor T cells built with the selected antibodies can kill specifically FGFR4-expressing RMS cells.

Cancer Research, 2007

1508 Peptides are becoming increasingly important as carrier for tumor treatment and diagnosis. B... more 1508 Peptides are becoming increasingly important as carrier for tumor treatment and diagnosis. By using large libraries of random peptides it is now possible to expand the repertoire of tumor targeting peptides. Aim of this work was to identify peptides that bind specifically rhabdomyosarcoma (RMS) cells and to select peptides which show the highest specificity toward RMS in vivo in xenotransplanted tumor mice model. RMS is the most common soft tissue sarcoma in children. Two main distinct histological groups exist: embryonal RMS (ERMS, 55%), and alveolar RMS (ARMS, 20%). ARMS is generally the most aggressive and subtype, with the poorest prognosis at diagnosis due to higher incidence of metastasis. No specific target is known so far for RMS and no target specific radiotracer is available for imaging of tumor mass, which represents a major limitation for early recognition, diagnosis and therapeutic imaging. We have created and validated new phage libraries displaying random cyclic ...

GTPase G-protein Acetylase Deacetylase Ribosomal subunit Direct Stimulatory Modification Direct I... more GTPase G-protein Acetylase Deacetylase Ribosomal subunit Direct Stimulatory Modification Direct Inhibitory Modification Multistep Stimulatory Modification Multistep Inhibitory Modification Tentative Stimulatory Modification Tentative Inhibitory Modification Separation of Subunits or Cleavage Products Joining of Subunits Translocation Transcriptional Stimulatory Modification Transcriptional Inhibitory Modification CELL SIGNALING TECHNOLOGY www.cellsignal.com

Cancers

Active drug delivery by tumor-targeting peptides is a promising approach to improve existing ther... more Active drug delivery by tumor-targeting peptides is a promising approach to improve existing therapies for rhabdomyosarcoma (RMS), by increasing the therapeutic effect and decreasing the systemic toxicity, e.g., by drug-loaded peptide-targeted nanoparticles. Here, we tested 20 different tumor-targeting peptides for their ability to bind to two RMS cell lines, Rh30 and RD, using quantum dots Streptavidin and biotin-peptides conjugates as a model for nanoparticles. Four peptides revealed a very strong binding to RMS cells: NCAM-1-targeting NTP peptide, nucleolin-targeting F3 peptide, and two Furin-targeting peptides, TmR and shTmR. F3 peptide showed the strongest binding to all RMS cell lines tested, low binding to normal control myoblasts and fibroblasts, and efficient internalization into RMS cells demonstrated by the cytoplasmic delivery of the Saporin toxin. The expression of the nucleophosphoprotein nucleolin, the target of F3, on the surface of RMS cell lines was validated by co...

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