Article Figures & Data
Figures
- Fig. 1.
In vitro cell association of liposomes with Namalwa cells as a function of concentration at 37°C (1 and 3) or 4°C (2 and 4). Nontargeted Stealth liposomes (•); SIL(αCD19) (▴); SIL(αCD20) (▪); Targeted combination of SIL(αCD19) + SIL(αCD20) (⋄). 1 and 2, liposomes were composed of Hydrogenated soy phosphatidylcholine (HSPC):cholesterol (Chol):distearoylphosphatidylethanolamine (mPEG-DSPE):maleimide-derivatized PEG2000-DSPE (Mal-PEG-DSPE; 2:1:0.1) or HSPC:Chol:mPEG-DSPE:Mal-PEG-DSPE (2:1:0.08:0.02). 3 and 4, liposomes were composed of egg sphingomyelin (SM):Chol:mPEG-DSPE (55:40:5) or SM:Chol:mPEG-DSPE:Mal-PEG-DSPE (55:40:4:1). Liposomes were labeled with [3H]CHE and incubated with 1 million Namalwa cells for 1 h after which the cells were washed with cold PBS to remove the unbound liposomes. The concentration of monoclonal antibodies on HSPC-SILs was 64 μg αCD19/μmol phospholipid (PL) or 54 μg αCD20/μmol PL and that on SM-SILs was 59 μg αCD19/μmol PL or 56 μg αCD20/μmol PL. Data are expressed as pmol PL/1 million cells. Each point is an average of three replicates from one representative experiment; bars, ± SD.
- Fig. 2.
Specific cell association of immunoliposomes with Namalwa cells as a function of concentration at 37°C (1 and 3) or 4°C (2 and 4). SIL(αCD19) (▴); SIL(αCD20) (▪); Targeted combination of SIL(αCD19) + SIL(αCD20) (⋄). ∗, calculated sum of cell association of SIL(αCD19) and SIL(αCD20). 1 and 2, liposomes were composed of hydrogenated soy phosphatidylcholine:cholesterol (Chol):distearoylphosphatidylethanolamine (mPEG-DSPE; 2:1:0.1) or hydrogenated soy phosphatidylcholine:Chol:mPEG-DSPE:maleimide-derivatized PEG2000-DSPE (2:1:0.08:0.02). 3 and 4, liposomes were composed of SM:Chol:mPEG-DSPE (55:40:5) or SM:Chol:mPEG-DSPE:maleimide-derivatized PEG2000-DSPE (55:40:4:1). Data are expressed as pmol phospholipid/1 million cells. Each point is an average of three replicates from one representative experiment; bars, ± SD.
Tables
- Table 1
Survival times of SCID mice after immunoliposomal DXRa treatments
SCID mice (5–7/group) were injected i.v. with 5 million Namalwa cells in 0.2 ml PBS. After 24 h they were injected i.v. in the tail vein with a single bolus dose of 3 mg/kg as free DXR or liposomal DXR. Liposomes were composed of HSPC:Chol:mPEG-DSPE (2:1:0.1) or HSPC:Chol:mPEG-DSPE:Mal-PEG-DSPE (2:1:0.08:0.02). DXR-loaded liposomes targeted with mAbs had 76 μg αCD19/μmol PL (40 molecules of αCD19/liposome) or 70 μg αCD20/μmol PL (37 molecules of αCD20/liposome), respectively. Free mAbs were dosed at 15 μg of αCD19 or 13 μg of αCD20 per mouse, which corresponds to the total amount of mAb received on immunoliposomes. Empty liposomes had 36 molecules of αCD19/liposome or 33 molecules of αCD20/liposome. The combination groups of free mAbs, empty or DXR-loaded liposomes had both components in equal parts. The combination of DXR-loaded αCD19 and αCD20-targeted liposomes was dosed at a total DXR dose of 3 mg/kg, and a total dose of 14 μg free mAbs per mouse.
Group Mean survival time ± SD (days) Percentage increase life span Long-term survivors (>150 days) Control (saline) 27.6 ± 0.5 0/5 free DXR 31.3 ± 2.7 13 0/5 DXR-HSPC-SL 28.6 ± 1.0 4 0/5 HSPC-SIL (αCD20) 30.5 ± 1.0 11 0/6 HSPC-SIL (αCD19) 31.5 ± 2.4 14 0/6 HSPC-SIL (αCD20) + HSPC-SIL (αCD19) 33.2 ± 2.0 20 0/6 αCD20 34.3 ± 1.1 24 0/6 αCD19 34.8 ± 1.0 26 0/6 αCD20 + αCD19 40.7 ± 2.0 47 0/6 DXR-HSPC-SL + αCD20 33.0 ± 1.3 20 0/6 DXR-HSPC-SL + αCD19 39.5 ± 1.0 43 0/6 DXR-HSPC-SIL (αCD20) 34.3 ± 4.2 24 0/7 DXR-HSPC-SIL (αCD19) 45.7 ± 4.7 66 0/7 DXR-HSPC-SIL (αCD20) + DXR-HSPC-SIL (αCD19) 48.6 ± 4.4 76 0/7 -
a DXR, doxorubicin; HSPC, hydrogenated soy phosphatidylcholine; Chol, cholesterol; mPEG-DSPE, methoxy (polyethylene glycol)2000 distearoylphosphatidylethanolamine; Mal-PEG-DSPE, maleimide-derivatized PEG2000-DSPE; mAb, monoclonal antibody; PL, phospholipid; SIL, Stealth immunoliposomes; SL, Stealth liposomes.
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- Table 2
Survival times of SCID mice after immunoliposomal VCRa treatments
SCID mice (6–7/group) were injected i.v. with 5 million Namalwa cells in 0.2 ml PBS. After 24 h they were injected i.v. in the tail vein with a single bolus dose of 0.66 mg/kg as free VCR or liposomal VCR. Liposomes were composed of SM:Chol:mPEG-DSPE (55:40:5) or SM:Chol:mPEG-DSPE:Mal-PEG-DSPE (55:40:4:1). Liposomes targeted with mAbs had 66 μg αCD19/μmol PL (34 molecules of αCD19/liposome) or 52 μg αCD20/μmol PL (27 molecules of αCD20/liposome, respectively). The combination group had VCR-SM-SIL (αCD19) and VCR-SM-SIL (αCD20; total dose = 0.66 mg/kg) in equal parts.
Group Mean survival time ± SD (days) Percentage increase life span Long-term survivors (>150 days) Control (saline) 25.4 ± 0.5 0/6 Free VCR 38.7 ± 4.0 53 0/6 VCR-SM-SL 31.9 ± 3.0 26 0/7 VCR-SM-SL + αCD20 44.7 ± 5.9 76 0/6 VCR-SM-SL + αCD19 62.3 ± 8.8 145 0/6 VCR-SM-SIL (αCD20) 49.0 ± 4.6 93 2/7 VCR-SM-SIL (αCD19) 66.0 ± 13.1 160 3/7 VCR-SM-SIL (αCD20) + VCR-SM-SIL (αCD19) 77.0, 91.0 203, 258 5/7 -
a VCR, vincristine; SM, egg sphingomyelin; Chol, cholesterol; mPEG-DSPE, distearoyl phosphatidyl; Mal-PEG-DSPE, maleimide-derivatized PEG2000-DSPE; mAb, monoclonal antibody; PL, phospholipid; SIL, Stealth immunoliposomes.
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Volume 10, Issue 7
