RESUMEN
Despite aggressive surgical and chemotherapy protocols, survival rates for osteosarcoma patients have not improved over the last 30 years. Therefore, novel therapeutic agents are needed. Receptor tyrosine kinases have emerged as targets for the development of new cancer therapies since their activation leads to enhanced proliferation, survival, and metastasis. In fact, aberrant expression and activation of RTKs have been associated with the progression of many cancers. Studies from our lab using phosphoproteomic screening identified RTKs that are activated and thus may contribute to the signaling within metastatic human osteosarcoma cells. Functional genomic screening using siRNA was performed to distinguish which of the activated RTKs contribute to in vitro phenotypes associated with metastatic potential (motility, invasion, colony formation, and cell growth). The resulting RTK hits were then validated using independent validation experiments. From these results, we identified four RTKs (Axl, EphB2, FGFR2, and Ret) that have not been previously studied in osteosarcoma and provide targets for the development of novel therapeutics.
Asunto(s)
Neoplasias Óseas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Osteosarcoma/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-ret/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Receptor EphB2/antagonistas & inhibidores , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/antagonistas & inhibidores , Antineoplásicos/uso terapéutico , Neoplasias Óseas/genética , Neoplasias Óseas/metabolismo , Neoplasias Óseas/patología , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundario , Osteosarcoma/genética , Osteosarcoma/metabolismo , Osteosarcoma/secundario , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-ret/genética , Proteínas Proto-Oncogénicas c-ret/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Proteínas Tirosina Quinasas Receptoras/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptor EphB2/genética , Receptor EphB2/metabolismo , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/genética , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal , Tirosina Quinasa del Receptor AxlRESUMEN
ß-nitrostyrene compounds, such as 3,4-methylenedioxy-ß-nitrostyrene (MNS), inhibit growth and induce apoptosis in tumor cells, but no reports have investigated their role in osteosarcoma. In this study, human osteosarcoma cell families with cell lines of varying tumorigenic and metastatic potential were utilized. Scrape motility assays, colony formation assays, and colony survival assays were performed with osteosarcoma cell lines, both in the presence and absence of MNS. Effects of MNS on human osteoblasts and airway epithelial cells were assessed in monolayer cultures. MNS decreased metastatic cell line motility by 72-76% and colony formation by 95-100%. MNS consistently disrupted preformed colonies in a time-dependent and dose-dependent manner. MNS had similar effects on human osteoblasts but little effect on airway epithelial cells. An inactive analog of MNS had no detectable effects, demonstrating specificity. MNS decreases motility and colony formation of osteosarcoma cells and disrupts preformed cell colonies, while producing little effect on pulmonary epithelial cells.
RESUMEN
Inhibitors of specific tyrosine kinases are attractive lead compounds for development of targeted chemotherapies for many tumors, including osteosarcoma. We asked whether inhibition of specific tyrosine kinases would decrease the motility, colony formation, and/or invasiveness by human osteosarcoma cell lines (TE85, MNNG, 143B, SAOS-2, LM-7). An EGF-R inhibitor reduced motility of all five cell lines by 50% to 80%. In contrast, an IGF-1R inhibitor preferentially reduced motility by 42% in LM-7 cells and a met inhibitor preferentially reduced motility by 80% in MNNG cells. The inhibitors of EGF-R, IGF-1R, and met reduced colony formation by more than 80% in all tested cell lines (TE85, MNNG, 143B). The EGF-R inhibitor reduced invasiveness by 62% in 143B cells. The JAK inhibitor increased motility of SAOS-2 and LM7 cells without affecting colony formation or invasiveness. Inhibitors of HER-2, NGF-R, and PDGF-Rs did not affect motility, invasiveness, or colony formation. These results support the hypothesis that specific tyrosine kinases regulate tumorigenesis and/or metastasis in osteosarcoma.
Asunto(s)
Neoplasias Óseas/genética , Osteosarcoma/genética , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Línea Celular Tumoral , Ensayos de Migración Celular , Humanos , Invasividad Neoplásica , Células Madre Neoplásicas/efectos de los fármacos , Receptor IGF Tipo 1/antagonistas & inhibidores , Células Tumorales CultivadasRESUMEN
The hypoxanthine phosphoribosyltransferase (Hprt) locus has been shown to have minimal influence on transgene expression when used as a surrogate site in the mouse genome. We have developed a method to transfer bacterial artificial chromosomes (BACs) as a single copy into the partially deleted Hprt locus of embryonic stem cells. BACs were modified by Cre/loxP recombination to contain the sequences necessary for homologous recombination into and complementation of the partially deleted Hprt locus. Modified BACs were shown to undergo homologous recombination into the genome intact, to be stably transmitted through the germ line of transgenic mice, and to be expressed in the proper tissue-specific manner. This technology will facilitate many studies in which correct interpretation of data depends on developmentally appropriate transgene expression in the absence of rearrangements or deletions of endogenous DNA.