[Direct contact with bone stromal HS-5 cells reduces the sensitivity of HEL to drugs]

This study was proposed to investigate the sensitivity and resistence of HEL cells co-cultured with bone marrow stromal HS-5 cells to chemotherapeutic drugs. HEL cells were cultured in direct contact with HS-5 cells for 6, 12, and 24 h. Cell Counting Kit-8 (CCK-8) was used to determine the sensitivity of HEL cell to cytarabine, methotrexate, VP16, and daunomycin. Cell cycle distribution was determined by using flow cytometry. Real-time RT-PCR was performed to detect the transcription levels of p19, p21, p27, MDR1, ABCG2 and bcl-2. Western blot was performed to determine the protein levels of p-Akt(Ser473), p-glycogen synthase kinase 3β (p-GSK3β(Ser9)), p-signal transducer and activator of transcription (p-STAT3(Tyr705)), Bcl-2, cleaved-Notch1(V1754), and Hes1. The results showed that chemo-sensitivity of HEL cells was remarkably reduced when co-cultured with HS-5 cells. HEL cells were arrested in the G(0)/G(1) phase after co-culture for 24 h. Transcription of p21 was significantly up-regulated at 6 h. Transcription of p19 decreased at 12 h and returned to baseline at 24 h. No significant changes in the mRNA expression of other genes were found. The expressions of p-Akt(Ser473), p-GSK3β(Ser9), cleaved-Notch1(V1754) and Bcl-2 proteins were significantly up-regulated in HEL cells, and Hes1 protein was significantly down-regulated. There was no change in p-STAT3(Tyr705) expression. It is concluded that the direct contact with HS-5 cells can reduce the chemo-sensitivity of HEL cells.