RESUMEN
In an effort to develop new agents and molecular targets for the treatment of cancer, aspargine-glycine-arginine (NGR)-targeted liposomal doxorubicin (TVT-DOX) is being studied. The NGR peptide on the surface of liposomal doxorubicin (DOX) targets an aminopeptidase N (CD13) isoform, specific to the tumor neovasculature, making it a promising strategy. To further understand the molecular mechanisms of action, we investigated cell binding, kinetics of internalization as well as cytotoxicity of TVT-DOX in vitro. We demonstrate the specific binding of TVT-DOX to CD13-expressing endothelial [human umbilical vein endothelial cells (HUVEC) and Kaposi sarcoma-derived endothelial cells (SLK)] and tumor (fibrosarcoma, HT-1080) cells in vitro. Following binding, the drug was shown to internalize through the endosomal pathway, eventually leading to the localization of doxorubicin in cell nuclei. TVT-DOX showed selective toxicity toward CD13-expressing HUVEC, sparing the CD13-negative colon-cancer cells, HT-29. Additionally, the nontargeted counterpart of TVT-DOX, Caelyx, was less cytotoxic to the CD13-positive HUVECs demonstrating the advantages of NGR targeting in vitro. The antitumor activity of TVT-DOX was tested in nude mice bearing human prostate-cancer xenografts (PC3). A significant growth inhibition (up to 60%) of PC3 tumors in vivo was observed. Reduction of tumor vasculature following treatment with TVT-DOX was also apparent. We further compared the efficacies of TVT-DOX and free doxorubicin in the DOX-resistant colon-cancer model, HCT-116, and observed the more pronounced antitumor effects of the TVT-DOX formulation over free DOX. The potential utility of TVT-DOX in a variety of vascularized solid tumors is promising.
Asunto(s)
Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Doxorrubicina/administración & dosificación , Doxorrubicina/farmacocinética , Oligopéptidos/metabolismo , Animales , Antineoplásicos/farmacología , Transporte Biológico , Antígenos CD13/metabolismo , Línea Celular Tumoral , Neoplasias del Colon , Doxorrubicina/farmacología , Resistencia a Antineoplásicos , Endocitosis , Endosomas/metabolismo , Humanos , Técnicas In Vitro , Liposomas , Masculino , Ratones , Ratones Desnudos , Neoplasias de la Próstata , Unión ProteicaRESUMEN
Previous studies have shown that human PSP94 can inhibit the growth of prostate cancer cells both in vitro and in vivo. To further validate this potential and investigate the protein within a homologous setting, we examined the effects of rat PSP94 on the growth of the rat prostate adenocarcinoma cell line PAIII in vitro. To generate rat PSP94, we used both a plasmid-based expression system and a recombinant rat PSP molecule. Rat PSP was shown to inhibit the growth and survival of PAIII cells in a dose-dependent manner with > 90 percent reductions in both observed. TUNEL and Annexin-V assays confirmed PAIII cell death to be via apoptosis.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Proliferación Celular/efectos de los fármacos , Neoplasias de la Próstata/tratamiento farmacológico , Proteínas de Secreción Prostática/farmacología , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Animales , Apoptosis/efectos de los fármacos , Northern Blotting , Western Blotting , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Clonación Molecular , Relación Dosis-Respuesta a Droga , Electroforesis en Gel de Poliacrilamida , Etiquetado Corte-Fin in Situ , Técnicas In Vitro , Masculino , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Ratas , Proteínas Recombinantes , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , TransfecciónRESUMEN
Preclinical studies of prostate cancer (CaP) have employed a genetically engineered mouse model, since there is no naturally occurring CaP in rodents. We have previously reported a new knock-in mouse adenocarcinoma prostate (KIMAP) model. In this study, we demonstrate that the new model possesses a tumor architecture of heterogeneity and multifocality similar to that of human CaP, by utilizing a new compound scoring system to compare with the PSP94 (approved gene symbol Msmb) gene-directed transgenic mouse CaP model (TGMAP). KIMAP mice showed a balanced distribution of tumor extent, which penetrated the prostate gland. Comparative studies on cDNA microarrays demonstrated that KIMAP tumors were upregulated with higher contents of immunoresponse genes, whereas PSP-TGMAP tumors had neuroendocrine (NE) differentiation. The majority of KIMAP mice did not progress to NE CaP, which was observed only at a very late stage and a low frequency. Several tumor marker genes characteristic of human CaP were uniquely identified in KIMAP tumors, including hepsin, maspin, Nkx3.1, CD10 and PSP94 (similar to PSA), etc. The differences between these two CaP models are attributed to the introduction of a single endogenous knock-in mutation. Due to the similarities between human CaP tumors and the PSP-KIMAP tumors, this preclinical model may supplement the current transgenic models to study CaP more accurately.