ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of metronomic chemotherapy of low dose phosphoramide combined with prednisolone (CP metronomic chemotherapy) on proliferation and apoptosis of RPMI 8226 cells, and to explore its regulating effect on Notch1/NF-κB signaling pathways.</p><p><b>METHODS</b>Experiment was divided into the DMSO control group, and the phosphoramide mustard (PM) group, the prednisolone group, the phosphoramide mustard plus prednisolone group (the CP group). RPMI 8226 cells were treated with different drugs, CCK-8 method was used to detect cell proliferation, flow cytometry was used to detect the cell cycle and apoptosis, reverse transcription PCR was used to detect Notch1 and NF-κB mRNA expression level.</p><p><b>RESULTS</b>Compared with DMSO control group, RPMI8226 cell proliferation inhibition rate in all the PM, prednisolone and CP groups increased significantly with prolonging of time (r of 0.994,0.996,0.999, respectively, P<0.001). And at the same time, the inhibitory rate of cell proliferation was significantly different; the cell inhibitory rate in PM group was lowest, that in CP group was highgest, that in prednissone group was intermediate (P<0.01). After 48 hours, compared with the DMSO control group, the G/Gcell proportion in treatment group increased significantly, S phase cell proportion decreased significantly, especially in PM and CP groups. The G/M phase cell proportion increased in PM group, while reduced in the prednisolone and the CP groups. After 48 hours, compared with the DMSO control group, RPMI 8226 cell apoptosis rate increased as follow: in PM, pre-dnisolone and CP group(P<0.01). After 48 hours, compared with the DMSO control group, Notch1 and NF-κB mRNA expression in the prednisolone, the PM and the CP group decreased significantly(P<0.001).</p><p><b>CONCLUSION</b>CP metronomic chemotherapy can significantly reduce RPMI 8226 cell proliferation, promote RPMI 8226 cell apoptosis, arrest RPMI 8226 cells mainly in the G/Gphase, and significantly reduce Notch1 and NF-κB expression levels. It is suggested that Notch1/NF-κB signaling pathways is involved in CP metronomic chemotherapy for MM.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To investigate effects of low-dose cyclophosphamide and prednisone (CP) metronomic chemotherapy on microvessel density of bone marrow, serum vascular endothelial growth factor (VEGF) and platelet derived growth factor BB (PDGF-BB)in multiple myeloma (MM) patients.</p><p><b>METHODS</b>54 refractory or relapsed MM patients were treated with CP metronomic chemotherapy consisted of oral cyclophosphamide (CTX, 50 mg/d) and prednisone (Pred, 15 mg/d). Bone marrow and peripheral blood of each patient were collected before and 2, 4, 6 months after treatment. Among the 37 assessable patients, 30 cases were responsive with the response rate of 81.08%. Another 17 cases were follow-uped less than 6 months or failure to obtain serum samples or lost to follow-up. Microvessel density of bone marrow was measured by immunohistochemistry and serum VEGF/PDGF-BB expression was analyzed by ELISA in the 37 assessable patients.</p><p><b>RESULTS</b>2, 4, 6 months following CP metronomic chemotherapy, microvessel densities of bone marrow in the responders were 33.1 ± 4.8/HP, 24.8 ± 3.7/HP, 19.7 ± 2.1/HP respectively; the expressions of VEGF were (394 ± 57) ng/L, (268 ± 32) ng/L and (217 ± 20) ng/L respectively; the expressions of PDGF-BB were (304 ± 31) ng/L, (274 ± 31) ng/L and (196 ± 22) ng/L respectively. After CP metronomic chemotherapy, there were significantly lower of microvessel density, VEGF and PDGF-BB levels than pretreatment \[MVD 48.5 ± 5.9/HP, VEGF (517 ± 60) ng/L, PDGF-BB (484 ± 60) ng/L\]in the responders (P < 0.01). While in the non-responders, after treated by CP metronomic chemotherapy for 2 months, microvessel density, the expression of VEGF and the expression of PDGF-BB were 32.5 ± 4.7/HP, 512 ± 39 ng/L and (452 ± 39) ng/L respectively. There were no significant changes of MVD, VEGF and PDGF-BB levels compared with pretreatment \[MVD 33.2 ± 5.6/HP,VEGF (498 ± 55) ng/L, PDGF-BB (488 ± 44) ng/L\] (P > 0.05).</p><p><b>CONCLUSIONS</b>Our findings suggested that continuous low-dose CP metronomic chemotherapy could decrease microvessel density of bone marrow in MM patients. Furthermore, it down-regulated expression of serum VEGF and PDGF-BB to exert its anti-angiogenesis in MM.</p>