RGD peptide inhibits tumor growth by affecting angiogenesis related signaling pathway of laryngeal cancer stem cells / El péptido RGD inhibe el crecimiento tumoral al afectar la vía de señalización relacionada con la angiogénesis de las células madre del cáncer de laringe

SUMMARY: This study is to investigate the role and mechanism of RGD peptide in laryngeal cancer stem cells (CSCs). Laryngeal cancer CD133+Hep-2 CSCs were sorted by flow cytometry. RGD peptide was co-cultured with sorted laryngeal CSCs. Cell proliferation was detected with CCK-8 assay. The mRNA levels of VEGF/VEGFR2/STAT 3/HIF-1α were detected with RT-PCR. The proteins of VEGF/ VEGFR2/STAT 3/HIF-1α were detected with Western blot. The sorted CSCs were inoculated into nude mice. Tumor volume was measured. Integrin αvβ3 expression in tumor tissues was analyzed with immunohistochemistry. The results showed that the ratio of CD133+ CSCs to the total number of cells was 1.34±0.87 %, while CD133-non-tumor stem cells accounted for 95.0±5.76 %. The sorted cancer stem cells grew well. The RGD peptide significantly inhibited the proliferation of CD133+Hep-2 laryngeal CSCs in a dose-dependent manner. The RGD peptide significantly inhibited the mRNA of VEGFR2, STAT3 and HIF-1α in laryngeal CSCs in a concentration-dependent manner. Consistently, the RGD peptide significantly inhibited the protein expression of VEGFR2, STAT3 and HIF-1α in laryngeal CSCs in a dose-dependent manner. At the same time, in vivo tumor experiments showed that the RGD peptide significantly inhibited tumor volume but not the body weight. Furthermore, RGD peptide significantly inhibited the expression of tumor angiogenesis-related protein integrin αvβ3. Our findings demonstrate that RGD peptide inhibits tumor cell proliferation and tumor growth. The underlying mechanism may that RGD inhibits tumor angiogenesis-related signaling pathways, thus affecting the tumor angiogenesis, and decreasing the progression of human laryngeal CSCs.

Este estudio se realizó para investigar el papel y el mecanismo del péptido RGD en las células madre del cáncer de laringe (CSC). Las CSC CD133+Hep-2 de cáncer de laringe se clasificaron mediante citometría de flujo. El péptido RGD se cocultivó con CSC laríngeas clasificadas. La proliferación celular se detectó con el ensayo CCK-8. Los niveles de ARNm de VEGF/VEGFR2/ STAT 3/HIF-1α se detectaron con RT-PCR. Las proteínas de VEGF/ VEGFR2/STAT 3/HIF-1α se detectaron con Western blot. Las CSC clasificadas se inocularon en ratones nudos. Se midió el volumen del tumor. La expresión de integrina αvβ3 en tejidos tumorales se analizó con inmunohistoquímica. Los resultados mostraron que la proporción de CSC CD133+ con respecto al número total de células fue de 1,34 ± 0,87 %, mientras que las células madre no tumorales CD133 representaron el 95,0 ± 5,76 %. Las células madre cancerosas clasificadas crecieron bien. El péptido RGD inhibió significativamente la proliferación de CSC laríngeas CD133+Hep-2 de una manera dependiente de la dosis. El péptido RGD inhibió significativamente el ARNm de VEGFR2, STAT3 y HIF-1α en CSC laríngeas de manera dependiente de la concentración. De manera consistente, el péptido RGD inhibió significativamente la expresión proteica de VEGFR2, STAT3 y HIF-1α en CSC laríngeas, de manera dependiente de la dosis. Al mismo tiempo, los experimentos con tumores in vivo mostraron que el péptido RGD inhibía significativamente el volumen del tumor pero no el peso corporal. Además, el péptido RGD inhibió significativamente la expresión de la proteína integrina αvβ3 relacionada con la angiogénesis tumoral. Nuestros hallazgos demuestran que el péptido RGD inhibe la proliferación de células tumorales y el crecimiento tumoral. El mecanismo subyacente puede ser que RGD inhiba las vías de señalización relacionadas con la angiogénesis tumoral, afectando así la angiogénesis tumoral y disminuyendo la progresión de las CSC laríngeas humanas.

In vivo characterization of the integrin beta3 as a receptor for Hantaan virus cellular entry

Binding of viruses to cell surface molecules is an essential step in viral infection. In vitro studies suggested that the alpha v beta3 integrin receptor is the epithelial cell receptor for Hantaan virus (HTNV). Whether beta3 is in vivo the only or central cellular receptor for HTNV infection is not known. To investigate the role of beta3 integrin for cellular entry of HTNV, we established an HTNV infection model in newborn murine pups. Infected pups died at an average age of 14.2 +/- 1.1 days with high levels of viral antigen detected in their brain, lung, and kidney. Pre-injection of blocking monoclonal antibodies (mAb) specific for either beta3 or av prolonged survival significantly to a maximal average survival of 19.7 +/- 1.5 days (P<0.01) and 18.4 +/- 0.9 days (P<0.01), respectively. XT-199, a chemical blocker of the alpha v beta3 receptor also prolonged survival to 19.5 +/- 1.3 days (P<0.01). In contrast to these receptor blockades, anti-HTNV antibody was not only able to prolong survival, but 20% of infected pups achieved long-term survival. An anti-murine beta1 antibody comparatively prolonged survival (19.0 +/- 1.2 days), suggesting that HTNV infection is partly mediated through integrin beta1 receptors as well as through beta3 receptors in vivo. Our data demonstrate that the beta3 receptor is important for HTNV infection in vivo, but also suggest that HTNV may utilize additional receptors beyond beta3 for cellular entry within an organism.