Skip to main content
. 2015 May 27;6(30):29833–29846. doi: 10.18632/oncotarget.4006

Figure 7. Specific inhibitors of RhoA, ERK1–2 and HIF-1α effectively reverse the MDR phenotype of IGHV UM cells.

Figure 7

IGHV UM cells were left untreated or treated with the ERK1–2 kinase inhibitor PD (10 μM), the RhoA kinase inhibitor Y276 (10 μM) and the HIF-1α inhibitor YC-1 (10 μM), both in the absence and in the presence of M2–10B4 SCs. A. HIF-1α activity. Co-culture with M2–10B4 SCs significantly increased the activity of HIF-1α (p = 0.0014). PD, Y276 and YC-1 significantly reduced the activity of HIF-1α in IGHV UM cells after 24 hours of culture, both in the absence (p always ≤ 0.0048) and in the presence (p always ≤ 0.0052) of SCs. B. MDR1 expression. Twenty four-hour co-culture with M2–10B4 SCs significantly increased the expression of MDR1 in IGHV UM cells (p < 0, 0001). After PD, Y276 and YC-1 treatment a significant decrease in MDR1 expression was observed in IGHV UM cells cultured alone (p always ≤ 0.001) and in the presence of SCs (p always ≤ 0.0001). C. Doxo intracellular accumulation. Intracellular Doxo was significantly lower in IGHV UM cells cultured with SCs than in IGHV UM cells cultured alone (p = 0.02). After 48-hour exposure to PD, Y276 and YC-1, Doxo accumulation was significantly increased, both in the absence (p always ≤ 0.003) and in the presence of M2–10B4 SCs (p always ≤ 0.0012). D. Percentage of CD19+/CD5+ viable cells. IGHV UM cells were exposed to 1 μM Doxo, used alone and in combination with each inhibitor (i.e. PD+Doxo, Y276+Doxo, YC-1+Doxo), both in the absence and in the presence of the M2–10B4 SCs. Cell viability was determined by Ann-V staining and cytofluorimetric analysis on CD19+/CD5+ cells after 48-hours of culture. Doxo alone, as well as the three inhibitors used as single agents, did not induce a decrease in cell viability. By contrast, the combinations PD+Doxo, Y276+Doxo and YC-1+Doxo significantly reduced the viability of IGHV UM cells both in the absence and in the presence (p always < 0.0001) of SCs. In panels A–D results are from 7 side-by-side experiments. Box and whiskers plot represent median values, first and third quartiles, and minimum and maximum values for each dataset.