Table 1. RGDfV increases ceramides and decreases sphingomyelins, and these changes are abrogated following ASM. knockdown.
| Ceramides (pmol/nmol Pi) | ||||||||||
| C14-CER | C16-CER | C18:0-CER | C18:1-CER | C20:0-CER | C22:0-CER | C24:0-CER | C24:1-CER | |||
| NC | 0.44±0.08 | 3.17±0.13 | 0.10±0.01 | 0.04±0.01 | 0.15±0.03 | 1.85±0.21 | 3.35±0.35 | 7.83±0.59 | ||
| NC+RGDfV | 0.47±0.07 | 4.76±0.29 | 0.14±0.01 | 0.05±0.01 | 0.13±0.01 | 1.94±0.14 | 4.26±0.17 | 10.14±1.09 | ||
| p value | NS | 0.008 | 0.042 | NS | NS | NS | 0.039 | 0.016 | ||
| ASM1 | 0.43±0.05 | 3.09±0.51 | 0.1±0.01 | 0.06±0.01 | 0.15±0.02 | 1.85±0.19 | 2.48±0.17 | 6.93±0.57 | ||
| ASM1+RGDfV | 0.36±0.02 | 3.30±0.29 | 0.1±0.01 | 0.06±0.01 | 0.11±0.01 | 1.94±0.23 | 3.4±0.16 | 7.59±0.24 | ||
| p value | NS | NS | NS | NS | NS | NS | 0.021 | NS | ||
| ASM2 | 0.36±0.01 | 2.60±0.21 | 0.09±0.01 | 0.06±0.01 | 0.14±0.01 | 1.77±0.14 | 3.16±0.37 | 7.07±0.31 | ||
| ASM2+RGDfV | 0.40±0.03 | 4.13±0.55 | 0.11±0.01 | 0.07±0.02 | 0.12±0.03 | 1.92±0.29 | 3.59±0.50 | 8.61±1.06 | ||
| p value | NS | 0.061 | NS | NS | NS | NS | NS | NS | ||
| Sphingomyelins (pmol/nmol Pi) | ||||||||||
| C14-SM | C16-SM | C18:0-SM | C18:1-SM | C20:0-SM | C22:0-SM | C22:1-SM | C24:0-SM | C24:1-SM | ||
| NC | 1.36±0.00 | 46.02±2.79 | 1.70±0.14 | 43.83±1.57 | 4.12±0.39 | 21.51±1.60 | 0.6±0.06 | 65.11±2.62 | 11.47±0.69 | |
| NC+RGDfV | 0.94±0.02 | 38.04±0.46 | 1.36±0.09 | 37.71±1.16 | 3.07±0.24 | 17.19±0.59 | 0.41±0.05 | 51.27±1.35 | 8.61±0.42 | |
| p value | 0.001 | 0.047 | 0.035 | NS | NS | NS | NS | 0.018 | 0.024 | |
| ASM1 | 1.31±0.08 | 50.47±1.17 | 2.28±0.22 | 59.5±3.06 | 5.04±0.53 | 27.67±1.03 | 0.63±0.10 | 73.40±2.45 | 12.29±0.87 | |
| ASM1+RGDfV | 1.23±0.20 | 51.04±2.61 | 2.25±0.20 | 63.94±6.96 | 4.81±0.34 | 27.02±2.17 | 0.57±0.08 | 73.59±3.99 | 11.55±0.99 | |
| p value | NS | NS | NS | NS | NS | NS | NS | NS | NS | |
| ASM2 | 1.55±0.06 | 57.51±10.26 | 3.63±0.55 | 89.99±9.11 | 7.58±1.28 | 35.79±6.49 | 0.98±0.19 | 82.08±15.31 | 15.09±2.76 | |
| ASM2+RGDfV | 1.23±0.12 | 56.39±14.60 | 3.73±1.07 | 99.79±27.60 | 7.46±1.88 | 34.78±8.66 | 0.90±0.29 | 79.38±13.78 | 14.67±4.20 | |
| p value | NS | NS | NS | NS | NS | NS | NS | NS | NS | |
Lysates of cells treated with siRNA and RGDfV as in Figs. 2C–D as were analyzed by mass spectrometry as detailed in Methods. Sphingolipid nomenclature: Ceramides are 1,3-hydroxy-2-amino alkanes (sphinganine) or alkenes (sphingosine) with fatty acid alkyl chains of C14 to C24 linked to the amino group of the sphingosine or sphinganine. A double bond in fatty acid alkyl chains is indicated as number “1” in the name. For example, C14-CER is sphingosine + C14 fatty acid without a double bond, and C18:1-CER is sphingosine + C18 fatty acid with a double bond. Sphingomyelins (SM) have sphingosine with the 1-hydroxyl group modified to phosphocholine as a core structural moiety, and the numbers for SM are the number of carbons of fatty acid chain. The levels of C20:1-CER, C22:1-CER and C20:1-SM were below the level of detection and were thus were not included in the table. Shown are means of three independent experiments ± SEM. NS: not statistically significant.