Location
Philadelphia, PA
Start Date
17-4-2026 1:30 PM
End Date
17-4-2026 2:30 PM
Description
Introduction:
Although Doxorubicin (DOX) is a widely prescribed chemotherapeutic agent, its clinical use is limited by cardiotoxicity (DIC) due to oxidative stress, mitochondrial dysfunction, and apoptosis in cardiac tissue. Dexrazoxane (DEX) is the only FDA-approved cardioprotective agent to prevent DIC. However, DEX may induce secondary malignancy. Mitochondria-targeted antioxidants (MTAs), such as mitoquinone (MitoQ), selectively accumulate within mitochondria to scavenge reactive oxygen species (ROS) at their primary site of production. Our previous findings demonstrated that MitoQ pre-treatment increased cell viability in DOX-treated H9c2 myoblasts. However, it remains unclear whether MitoQ can selectively protect cardiomyocytes without compromising DOX’s anticancer efficacy, a critical requirement for potential clinical application.
Methods:
H9c2 myoblasts were treated with DOX (500 nM - 60 μM, n=5), MitoQ (0.1 μM - 20 μM, n=5), or DEX (1 μM - 500 μM, n=5) to determine the dose-response. To evaluate the effects of MitoQ pretreatment, H9c2 cells were incubated with MitoQ (0.1 μM - 20 μM, n=5) or DEX (1 μM - 500 μM, n=5) for 30 minutes or 24 hours, followed by washout and incubation with 40 μM DOX for an additional 24 hours. In the co-treatment groups, cells received MitoQ or DEX simultaneously with 40 μM DOX for 24 hours. Thereafter, cell viability was assessed using Cell Counting Kit-8 (CCK-8) by measuring absorbance at 450 nm. Similar experiments were conducted on 22RV1 prostate cancer cells to determine the effects of MitoQ and DEX on DOX’s anti-cancer effects. Data was normalized to untreated controls or the DOX 40 μM-treated positive controls. Furthermore, cleaved caspase-3 expression in H9c2 protein samples was detected by western blot and normalized to the expression of ꞵ-actin.
Results:
DOX dose-dependently reduced H9c2 cell viability by 44±6% (1 μM) and 54±2% (40 μM, n=5) when compared with nontreated H9c2 cells after incubation for 24 hours. Similarly, 1 μM and 40 μM DOX decreased 22RV1 cancer cell viability by 31±4% (n=5) and 53±5% (n=5) when compared to untreated control. Pretreatment of H9c2 cells with MitoQ (5 μM, n=3) for 24 hours showed increased viability by 97±13% (n=3) compared to DOX 40 μM alone. This protection was greater than that observed with 5 μM MitoQ when given pre-treatment for 30-minute (9±6%, n=3), co-treatment for 30-minutes (-5±13%) and 24 hours (11±15%), or DEX (1-500 μM) pre- or co-treatment. In contrast, MitoQ (5 μM, n=4) pre-treatment for 24 hours showed additional reduction (22±1%, n=4) in cell viability, whereas MitoQ co-treatment and DEX pre/co-treatment exhibited the similar cell viability when compared to DOX (40 μM) in 22RV1 cells. Last, DOX (1 - 20 μM), not MitoQ (1 - 5 μM), increased cleaved caspase-3 expression after incubation for 24-hours.
Conclusion:
DOX produced comparable dose-dependent cytotoxicity in H9c2 myoblast and 22RV1 prostate cancer cells, possibly by apoptosis. Notably, 24-hour MitoQ pre-treatment dramatically protected H9c2 myoblasts while slightly enhancing DOX’s cytotoxicity in prostate cancer cells, which is better than DEX’s effects. The underlying mechanisms of MitoQ-mediated cardioprotection will be further evaluated.
Embargo Period
6-3-2026
Included in
Investigating the Effect of Mitoquinone on Doxorubicin-induced Damage in H9c2 myoblast
Philadelphia, PA
Introduction:
Although Doxorubicin (DOX) is a widely prescribed chemotherapeutic agent, its clinical use is limited by cardiotoxicity (DIC) due to oxidative stress, mitochondrial dysfunction, and apoptosis in cardiac tissue. Dexrazoxane (DEX) is the only FDA-approved cardioprotective agent to prevent DIC. However, DEX may induce secondary malignancy. Mitochondria-targeted antioxidants (MTAs), such as mitoquinone (MitoQ), selectively accumulate within mitochondria to scavenge reactive oxygen species (ROS) at their primary site of production. Our previous findings demonstrated that MitoQ pre-treatment increased cell viability in DOX-treated H9c2 myoblasts. However, it remains unclear whether MitoQ can selectively protect cardiomyocytes without compromising DOX’s anticancer efficacy, a critical requirement for potential clinical application.
Methods:
H9c2 myoblasts were treated with DOX (500 nM - 60 μM, n=5), MitoQ (0.1 μM - 20 μM, n=5), or DEX (1 μM - 500 μM, n=5) to determine the dose-response. To evaluate the effects of MitoQ pretreatment, H9c2 cells were incubated with MitoQ (0.1 μM - 20 μM, n=5) or DEX (1 μM - 500 μM, n=5) for 30 minutes or 24 hours, followed by washout and incubation with 40 μM DOX for an additional 24 hours. In the co-treatment groups, cells received MitoQ or DEX simultaneously with 40 μM DOX for 24 hours. Thereafter, cell viability was assessed using Cell Counting Kit-8 (CCK-8) by measuring absorbance at 450 nm. Similar experiments were conducted on 22RV1 prostate cancer cells to determine the effects of MitoQ and DEX on DOX’s anti-cancer effects. Data was normalized to untreated controls or the DOX 40 μM-treated positive controls. Furthermore, cleaved caspase-3 expression in H9c2 protein samples was detected by western blot and normalized to the expression of ꞵ-actin.
Results:
DOX dose-dependently reduced H9c2 cell viability by 44±6% (1 μM) and 54±2% (40 μM, n=5) when compared with nontreated H9c2 cells after incubation for 24 hours. Similarly, 1 μM and 40 μM DOX decreased 22RV1 cancer cell viability by 31±4% (n=5) and 53±5% (n=5) when compared to untreated control. Pretreatment of H9c2 cells with MitoQ (5 μM, n=3) for 24 hours showed increased viability by 97±13% (n=3) compared to DOX 40 μM alone. This protection was greater than that observed with 5 μM MitoQ when given pre-treatment for 30-minute (9±6%, n=3), co-treatment for 30-minutes (-5±13%) and 24 hours (11±15%), or DEX (1-500 μM) pre- or co-treatment. In contrast, MitoQ (5 μM, n=4) pre-treatment for 24 hours showed additional reduction (22±1%, n=4) in cell viability, whereas MitoQ co-treatment and DEX pre/co-treatment exhibited the similar cell viability when compared to DOX (40 μM) in 22RV1 cells. Last, DOX (1 - 20 μM), not MitoQ (1 - 5 μM), increased cleaved caspase-3 expression after incubation for 24-hours.
Conclusion:
DOX produced comparable dose-dependent cytotoxicity in H9c2 myoblast and 22RV1 prostate cancer cells, possibly by apoptosis. Notably, 24-hour MitoQ pre-treatment dramatically protected H9c2 myoblasts while slightly enhancing DOX’s cytotoxicity in prostate cancer cells, which is better than DEX’s effects. The underlying mechanisms of MitoQ-mediated cardioprotection will be further evaluated.