The Effects Of NOTCH1 And VEGF On Tumor Growth And Angiogenesis In A Mouse Model Of Multiple Myeloma

Objective:To investigate Notch1 on the effects of RPMI8226 cell growth and VEGF, Human RPMI8226 multiple myeloma cells were infected with Notch1-ICN retrovirus, so as to reveal the pathogenesis of myeloma and provide the basis for molecular targeted therapy.Materials and Methods:1.Human RPMI8226 multiple myeloma cells were infected with Notch1-ICN and Notch1-CON retrovirus stocks.2.CCK-8 was used to detect the proliferation of MM cells and sensitivity to chemotherapeutic drugs.3.Protein expression was detected by Western blot analysis.4.VEGF secretion was measured by ELISA assays.Results:1.Human RPMI8226 multiple myeloma cells were infected with Notch1-ICN and Notch1-CON retrovirus stocks successfully.2.Notch1 protein in RPMI8226-ICN cells expressed higher than that of RPMI8226 or RPMI-8226-CON cells indicating Notch1 signal activation.3.CCK-8 results showed that RPMI8226-ICN cell proliferation was significantly increased. IC50 values of Velcade in RPMI-8226-CON, and RPMI-8226-ICN were 2.14μmol/L and 3.16μmol/L (P<0.05). No marked difference was observed between RPMI-8226 group and RPMI-8226-CON group.4.ELISA results showed that Notch1 overexpression increased VEGF secretion.Conclusion:1.Notch1 overexpression promoted RPMI8226 cell proliferation2.Notch1 overexpression in RPMI8226 cells can reduce the sensitivity to drug.3.Notch1 overexpression can promote VEGF secretion, indicating that there is a relationship betweenVEGF and Notch1, which regulate VEGF expression. Objective:To study the effects of Notch overexpression on tumor growth and angiogenesis in multiple myeloma in vivo, myeloma cells was infected by Notch-ICN virus, and then was inoculated NOD/SCID mouse model.Materials and Methods:1 . RPMI-8226, RPMI-8226-CON, and RPMI-8226-ICN cells were inoculated subcutaneously in mice to establish xenograft mouse model of myeloma.2.The tumor size was continuously monitored in vivo.3.The expression of Notch1 and VEGF in different groups were detected by immunohistochemistry. Tumor sections of each group were stained with anti-CD34 antibody to evaluate the microvessel density.Results:1.The new models of human multiple myeloma using NOD/SCID mouse were successfully established.2.The transplanted tumor formation rate: On the average 7 (5-14) days, measurable tumors could be seen in 18 NOD/SCID mice left groin. The tumor formation rate was 100%.3.The general condition of experimental animals: RPMI-8226 Group: NOD/SCID mice mental condition, activity, skin condition, dietary water intake and body weight were not found significant anomalies; Volume change test results showed that of Notch1 overexpression promoted tumor growth in vivo, accelerated tumor formation. The mean tumor volume in RPMI-8226-ICN group was higher than that in the RPMI-8226-CON group. At all time point the mean total tumor volume did not differ between the RPMI-8226 and RPMI-8226-CON groups.4 . Notch1 and VEGF were found to be expressed to a higher extent in RPMI-8226-ICN group as compared to other groups. The mean MVD was increased apparently in the tumors of the RPMI-8226-ICN group compared with RPMI-8226 or RPMI-8226-CON group.Conclusion:1.Notch1 overexpression can promote tumor growth in multiple myeloma.2.Notch1 overexpression can promote multiple myeloma tumor angiogenesis.3.Notch signaling pathway is expected to become myeloma proliferation and anti-tumor anti-angiogenesis therapeutic target.