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1126
Proceedings of the 48th Annual ASTRO Meeting
Group
*Tumor Doubling Time (days)†
*PSA Doubling Time (days)†
MM AS-MDM2 MM⫹RT AS-MDM2⫹RT MM⫹AD AS-MDM2⫹AD MM⫹RT⫹AD AS-MDM2⫹RT⫹AD
19 (12) 12 (7) 18 (11) 23 (10) 27 (10) 6 (6) 17 (9) 28 (5)
25 (12) 17 (7) 25 (11) 22 (10) 14 (10) 8 (6) 13 (9) 24 (5)
Tumor Volume at 10 wks (mm3)† 277.3 254.1 247.9 79‡ 307.6 179.6 146.8 26.3‡
S203
PSA at 10 wks (ng/ml)† 33.9 32.9 34.6 22.1 25.7 19.6 20.3 6.4
FFTVF 16% 30% 18% 30% 25% 62% 38% 77%
(2/12) (3/10) (2/11) (3/10) (3/12) (8/13)‡ (5/13) (10/13)‡
FFBF 16% 30% 18% 38% 25% 54% 46% 69%
(2/12) (3/10) (2/11) (5/13) (3/12) (7/13)‡ (6/13) (9/13)
* Doubling times are calculated only from mice (number indicated in pretences) where tumor volume/PSA show an upward trend after treatment † Values estimated from exponential fits of longitudinal data ‡ Statistical significant difference (p⬍0.05), compared to the group above
Author Disclosure: R. Stoyanova, None; P. Hachem, None; H.H. Hensley, None; H. Kwon, None; A. Pollack, None.
1126
Antisense MDM2 Oligonucleotides Sensitize Androgen-Insensitive Human Prostate Cancer Cells To Androgen Deprivation In Vitro And In Vivo
Z. Mu1, P. Hachem1, H. Hensley1, R. Stoyanova1, A. L. Hanlon1, S. Agrawal2, A. Pollack1 1 Fox Chase Cancer Center, Philadelphia, PA, 2Idera Pharmaceuticals, Cambridge, MA Background: Men with high risk prostate cancer typically have heterogeneous primary tumors and/or micrometastatic disease, and would benefit from not only sensitization to radiation (RT), but also sensitization to androgen deprivation (AD). We have previously shown that antisense MDM2 (AS) sensitizes wild type LNCaP cells to androgen deprivation (AD), radiation (RT) and the combination in vitro. As an extension of these studies, a growth-inhibition resistant human LNCaP cell line (LNCaP-Res) was developed. These cells are representative of the early transition to androgen dependence and likely are present in many patients with locally-advanced tumors. Purpose/Objective(s): The objectives are to 1) determine if LNCaP-Res cells continue to respond to AS, with and without AD; and 2) compare these responses to those in bcl-2 overexpressing LNCaP (LNCaP-BST) cells. The latter comparison was made because LNCaP-Res cells overexpress bcl-2 when grown in AD medium. Materials/Methods: The LNCaP-Res line was established by long-term culture of LNCaP cells in AD medium for ⬎12 mo. Cell death was quantified by Annexin V, Caspase 3⫹7 activity and clonogenic cell survival. For the in vivo studies, LNCaP-Res cells were implanted orthotopically into the prostates of intact and castrated nude mice. Tumor growth was monitored by MRI. AS and the mismatch control (MM) were given by i.p. injection at doses 25mg/kg per day, 5 days /week for 15 days. Statistical comparisons between groups were accomplished with Student’s t-Test for the tumor volume doubling times and Fisher Exact Test for freedom from tumor volume failure (FFTVF; endpoint of ⬍100 mm3 at day 30). Results: AS caused a significant reduction in MDM2 expression and an increase in p53 and p21 expression in wild-type LNCaP, LNCaP-Res and LNCaP-BST cell lines. AS⫹AD resulted in significantly higher levels of apoptosis, compared to AS or AD alone, even in LNCaP-Res cells. Moreover, significant LNCaP-Res in vivo tumor growth inhibition was observed from the combination of AS⫹AD (Table). The mean doubling time from AS⫹AD (21 days) was significantly longer than for AS alone (6 days) (p⬍0.05). The percentage of FFTVF was significantly higher from AS⫹AD (54%) over AS alone (0%; p⬍0.05) and there was a trend for AS⫹AD over MM⫹AD (14%; p⫽0.09). Conclusions: AS enhanced LNCaP-Res apoptotic cell death in vitro and tumor inhibition in vivo when combined with AD, despite the fact that LNCaP-Res cells were no longer growth inhibited by AD. AS-MDM2 has promise for the treatment of men with high risk clinically localized prostate cancer, as well as those with early hormone refractory disease.
The antitumor effects of AS alone or in combination with AD (castration) in nude mice bearing LNCaP-
Mice
Group
Mice (n)
Normal Normal Castrated (AD) Castrated (AD)
MM AS MM AS
5 4 7 7
Baseline Tumor Size (mm3) M ⫹ SEM
Doubling Time (days) Mean (range)
FFTVF
⫹ ⫹ ⫹ ⫹
8 (5.1-15.6) 6 (3.4-7.1) 9 (4.6-10.6) 21 (5.7-77.5)
0% (0/5) 0% (0/4) 14% (1/7) 54% (4/7)
31.3 23.1 30.6 16.5
6.5 8.1 6.4 2.8
Author Disclosure: Z. Mu, None; P. Hachem, None; H. Hensley, None; R. Stoyanova, None; A.L. Hanlon, None; S. Agrawal, None; A. Pollack, Varian, B. Research Grant; TAP Pharmaceuticals;Astrazeneca, D. Speakers Bureau/Honoraria.
Group
*Tumor Doubling Time (days)†
*PSA Doubling Time (days)†
MM AS-MDM2 MM⫹RT AS-MDM2⫹RT MM⫹AD AS-MDM2⫹AD MM⫹RT⫹AD AS-MDM2⫹RT⫹AD
19 (12) 12 (7) 18 (11) 23 (10) 27 (10) 6 (6) 17 (9) 28 (5)
25 (12) 17 (7) 25 (11) 22 (10) 14 (10) 8 (6) 13 (9) 24 (5)
Tumor Volume at 10 wks (mm3)† 277.3 254.1 247.9 79‡ 307.6 179.6 146.8 26.3‡
S203
PSA at 10 wks (ng/ml)† 33.9 32.9 34.6 22.1 25.7 19.6 20.3 6.4
FFTVF 16% 30% 18% 30% 25% 62% 38% 77%
(2/12) (3/10) (2/11) (3/10) (3/12) (8/13)‡ (5/13) (10/13)‡
FFBF 16% 30% 18% 38% 25% 54% 46% 69%
(2/12) (3/10) (2/11) (5/13) (3/12) (7/13)‡ (6/13) (9/13)
* Doubling times are calculated only from mice (number indicated in pretences) where tumor volume/PSA show an upward trend after treatment † Values estimated from exponential fits of longitudinal data ‡ Statistical significant difference (p⬍0.05), compared to the group above
Author Disclosure: R. Stoyanova, None; P. Hachem, None; H.H. Hensley, None; H. Kwon, None; A. Pollack, None.
1126
Antisense MDM2 Oligonucleotides Sensitize Androgen-Insensitive Human Prostate Cancer Cells To Androgen Deprivation In Vitro And In Vivo
Z. Mu1, P. Hachem1, H. Hensley1, R. Stoyanova1, A. L. Hanlon1, S. Agrawal2, A. Pollack1 1 Fox Chase Cancer Center, Philadelphia, PA, 2Idera Pharmaceuticals, Cambridge, MA Background: Men with high risk prostate cancer typically have heterogeneous primary tumors and/or micrometastatic disease, and would benefit from not only sensitization to radiation (RT), but also sensitization to androgen deprivation (AD). We have previously shown that antisense MDM2 (AS) sensitizes wild type LNCaP cells to androgen deprivation (AD), radiation (RT) and the combination in vitro. As an extension of these studies, a growth-inhibition resistant human LNCaP cell line (LNCaP-Res) was developed. These cells are representative of the early transition to androgen dependence and likely are present in many patients with locally-advanced tumors. Purpose/Objective(s): The objectives are to 1) determine if LNCaP-Res cells continue to respond to AS, with and without AD; and 2) compare these responses to those in bcl-2 overexpressing LNCaP (LNCaP-BST) cells. The latter comparison was made because LNCaP-Res cells overexpress bcl-2 when grown in AD medium. Materials/Methods: The LNCaP-Res line was established by long-term culture of LNCaP cells in AD medium for ⬎12 mo. Cell death was quantified by Annexin V, Caspase 3⫹7 activity and clonogenic cell survival. For the in vivo studies, LNCaP-Res cells were implanted orthotopically into the prostates of intact and castrated nude mice. Tumor growth was monitored by MRI. AS and the mismatch control (MM) were given by i.p. injection at doses 25mg/kg per day, 5 days /week for 15 days. Statistical comparisons between groups were accomplished with Student’s t-Test for the tumor volume doubling times and Fisher Exact Test for freedom from tumor volume failure (FFTVF; endpoint of ⬍100 mm3 at day 30). Results: AS caused a significant reduction in MDM2 expression and an increase in p53 and p21 expression in wild-type LNCaP, LNCaP-Res and LNCaP-BST cell lines. AS⫹AD resulted in significantly higher levels of apoptosis, compared to AS or AD alone, even in LNCaP-Res cells. Moreover, significant LNCaP-Res in vivo tumor growth inhibition was observed from the combination of AS⫹AD (Table). The mean doubling time from AS⫹AD (21 days) was significantly longer than for AS alone (6 days) (p⬍0.05). The percentage of FFTVF was significantly higher from AS⫹AD (54%) over AS alone (0%; p⬍0.05) and there was a trend for AS⫹AD over MM⫹AD (14%; p⫽0.09). Conclusions: AS enhanced LNCaP-Res apoptotic cell death in vitro and tumor inhibition in vivo when combined with AD, despite the fact that LNCaP-Res cells were no longer growth inhibited by AD. AS-MDM2 has promise for the treatment of men with high risk clinically localized prostate cancer, as well as those with early hormone refractory disease.
The antitumor effects of AS alone or in combination with AD (castration) in nude mice bearing LNCaP-
Mice
Group
Mice (n)
Normal Normal Castrated (AD) Castrated (AD)
MM AS MM AS
5 4 7 7
Baseline Tumor Size (mm3) M ⫹ SEM
Doubling Time (days) Mean (range)
FFTVF
⫹ ⫹ ⫹ ⫹
8 (5.1-15.6) 6 (3.4-7.1) 9 (4.6-10.6) 21 (5.7-77.5)
0% (0/5) 0% (0/4) 14% (1/7) 54% (4/7)
31.3 23.1 30.6 16.5
6.5 8.1 6.4 2.8
Author Disclosure: Z. Mu, None; P. Hachem, None; H. Hensley, None; R. Stoyanova, None; A.L. Hanlon, None; S. Agrawal, None; A. Pollack, Varian, B. Research Grant; TAP Pharmaceuticals;Astrazeneca, D. Speakers Bureau/Honoraria.