TY  - JOUR
AU  - Vucicevic, Ljubica
AU  - Misirkić, Maja
AU  - Janjetović, Kristina D.
AU  - Vilimanovich, Urosh
AU  - Sudar, Emina
AU  - Isenović, Esma R.
AU  - Prica, Marko
AU  - Harhaji-Trajković, Ljubica M.
AU  - Kravić-Stevović, Tamara K.
AU  - Bumbaširević, Vladimir Ž.
AU  - Trajković, Vladimir S.
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4180
AB  - In the present study, we report that compound C, an inhibitor of a key intracellular energy sensor AMP-activated protein kinase (AMPK), can induce autophagy in cancer cells. The induction of autophagy in U251 human glioma cell line was demonstrated by acridine orange staining of intracellular acidic vesicles, Beclin 1 induction, p62 decrease and conversion of LC3-I to autophagosome-associated LC3-II in the presence of proteolysis inhibitors. The presence of autophagosome-like vesicles was confirmed by transmission electron microscopy. Compound C-mediated inhibition of AMPK and raptor in U251 cells was associated with paradoxical decrease in phosphorylation of AMPK/raptor-repressed mTOR, a major negative regulator of autophagy, and its downstream target p70S6K. The phosphorylation of an mTOR activator Akt and the PI3K-activating kinase Src was also impaired in compound C-treated cells. The siRNA-mediated AMPK silencing did not reduce the activity of the Akt/mTOR/p70S6K pathway and AMPK activators metformin and AICAR failed to block compound C-induced autophagy. Autophagy inhibitors bafilomycin and chloroquine significantly increased the cytotoxicity of compound C towards U251 cells, as confirmed by increase in lactate dehydrogenase release, DNA fragmentation and caspase-3 activation. Similar effects of compound C were also observed in C6 rat glioma, L929 mouse fibrosarcoma and B16 mouse melanoma cell lines. Since compound C has previously been reported to suppress AMPK-dependent autophagy in different cell types, our findings suggest that the effects of compound C on autophagy might be dose-, cell type- and/or context-dependent. By demonstrating the ability of compound C to induce autophagic response in cancer cells via AMPK inhibition-independent downregulation of Akt/mTOR pathway, our results warrant caution when using compound C to inhibit AMPK-dependent cellular responses, but also support further exploration of compound C and related molecules as potential anticancer agents.
T2  - Autophagy
T1  - Compound C induces protective autophagy in cancer cells through AMPK inhibition-independent blockade of Akt/mTOR pathway
VL  - 7
IS  - 1
SP  - 40
EP  - 50
DO  - 10.4161/auto.7.1.13883
ER  - 

@article{
author = "Vucicevic, Ljubica and Misirkić, Maja and Janjetović, Kristina D. and Vilimanovich, Urosh and Sudar, Emina and Isenović, Esma R. and Prica, Marko and Harhaji-Trajković, Ljubica M. and Kravić-Stevović, Tamara K. and Bumbaširević, Vladimir Ž. and Trajković, Vladimir S.",
year = "2011",
abstract = "In the present study, we report that compound C, an inhibitor of a key intracellular energy sensor AMP-activated protein kinase (AMPK), can induce autophagy in cancer cells. The induction of autophagy in U251 human glioma cell line was demonstrated by acridine orange staining of intracellular acidic vesicles, Beclin 1 induction, p62 decrease and conversion of LC3-I to autophagosome-associated LC3-II in the presence of proteolysis inhibitors. The presence of autophagosome-like vesicles was confirmed by transmission electron microscopy. Compound C-mediated inhibition of AMPK and raptor in U251 cells was associated with paradoxical decrease in phosphorylation of AMPK/raptor-repressed mTOR, a major negative regulator of autophagy, and its downstream target p70S6K. The phosphorylation of an mTOR activator Akt and the PI3K-activating kinase Src was also impaired in compound C-treated cells. The siRNA-mediated AMPK silencing did not reduce the activity of the Akt/mTOR/p70S6K pathway and AMPK activators metformin and AICAR failed to block compound C-induced autophagy. Autophagy inhibitors bafilomycin and chloroquine significantly increased the cytotoxicity of compound C towards U251 cells, as confirmed by increase in lactate dehydrogenase release, DNA fragmentation and caspase-3 activation. Similar effects of compound C were also observed in C6 rat glioma, L929 mouse fibrosarcoma and B16 mouse melanoma cell lines. Since compound C has previously been reported to suppress AMPK-dependent autophagy in different cell types, our findings suggest that the effects of compound C on autophagy might be dose-, cell type- and/or context-dependent. By demonstrating the ability of compound C to induce autophagic response in cancer cells via AMPK inhibition-independent downregulation of Akt/mTOR pathway, our results warrant caution when using compound C to inhibit AMPK-dependent cellular responses, but also support further exploration of compound C and related molecules as potential anticancer agents.",
journal = "Autophagy",
title = "Compound C induces protective autophagy in cancer cells through AMPK inhibition-independent blockade of Akt/mTOR pathway",
volume = "7",
number = "1",
pages = "40-50",
doi = "10.4161/auto.7.1.13883"
}

Vucicevic, L., Misirkić, M., Janjetović, K. D., Vilimanovich, U., Sudar, E., Isenović, E. R., Prica, M., Harhaji-Trajković, L. M., Kravić-Stevović, T. K., Bumbaširević, V. Ž.,& Trajković, V. S.. (2011). Compound C induces protective autophagy in cancer cells through AMPK inhibition-independent blockade of Akt/mTOR pathway. in Autophagy, 7(1), 40-50.
https://doi.org/10.4161/auto.7.1.13883

Vucicevic L, Misirkić M, Janjetović KD, Vilimanovich U, Sudar E, Isenović ER, Prica M, Harhaji-Trajković LM, Kravić-Stevović TK, Bumbaširević VŽ, Trajković VS. Compound C induces protective autophagy in cancer cells through AMPK inhibition-independent blockade of Akt/mTOR pathway. in Autophagy. 2011;7(1):40-50.
doi:10.4161/auto.7.1.13883 .

Vucicevic, Ljubica, Misirkić, Maja, Janjetović, Kristina D., Vilimanovich, Urosh, Sudar, Emina, Isenović, Esma R., Prica, Marko, Harhaji-Trajković, Ljubica M., Kravić-Stevović, Tamara K., Bumbaširević, Vladimir Ž., Trajković, Vladimir S., "Compound C induces protective autophagy in cancer cells through AMPK inhibition-independent blockade of Akt/mTOR pathway" in Autophagy, 7, no. 1 (2011):40-50,
https://doi.org/10.4161/auto.7.1.13883 . .

TY  - JOUR
AU  - Vucicevic, Ljubica
AU  - Misirkić, Maja
AU  - Janjetović, Kristina D.
AU  - Harhaji-Trajković, Ljubica M.
AU  - Prica, Marko
AU  - Stevanović, Darko
AU  - Isenović, Esma R.
AU  - Sudar, Emina
AU  - Šumarac-Dumanović, Mirjana
AU  - Micic, Dragan
AU  - Trajković, Vladimir S.
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3690
AB  - We investigated the effect of compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), on proliferation and viability of human U251 and rat C6 glioma cell lines. Compound C caused G(2)/M cell cycle block, accompanied by apoptotic glioma cell death characterized by caspase activation, phosphatidylserine exposure and DNA fragmentation. The mechanisms underlying the pro-apoptotic action of compound C involved induction of oxidative stress and downregulation of antiapoptotic molecule Bcl-2, while no alteration of pro-apoptotic Bax was observed. Compound C diminished AMPK phosphorylation and enzymatic activity, resulting in reduced phosphorylation of its target acetyl CoA carboxylase. AMPK activators metformin and AICAR partly prevented the cell cycle block, oxidative stress and apoptosis induced by compound C. The small interfering RNA (siRNA) targeting of human AMPK mimicked compound C-induced G(2)/M cell cycle arrest, but failed to induce oxidative stress and apoptosis in U251 glioma cells. In conclusion, our data indicate that AMPK inhibition is required, but not sufficient for compound C-mediated apoptotic death of glioma cells. (c) 2009 Elsevier Inc. All rights reserved.
T2  - Biochemical Pharmacology
T1  - AMP-activated protein kinase-dependent and -independent mechanisms underlying in vitro antiglioma action of compound C
VL  - 77
IS  - 11
SP  - 1684
EP  - 1693
DO  - 10.1016/j.bcp.2009.03.005
ER  - 

@article{
author = "Vucicevic, Ljubica and Misirkić, Maja and Janjetović, Kristina D. and Harhaji-Trajković, Ljubica M. and Prica, Marko and Stevanović, Darko and Isenović, Esma R. and Sudar, Emina and Šumarac-Dumanović, Mirjana and Micic, Dragan and Trajković, Vladimir S.",
year = "2009",
abstract = "We investigated the effect of compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), on proliferation and viability of human U251 and rat C6 glioma cell lines. Compound C caused G(2)/M cell cycle block, accompanied by apoptotic glioma cell death characterized by caspase activation, phosphatidylserine exposure and DNA fragmentation. The mechanisms underlying the pro-apoptotic action of compound C involved induction of oxidative stress and downregulation of antiapoptotic molecule Bcl-2, while no alteration of pro-apoptotic Bax was observed. Compound C diminished AMPK phosphorylation and enzymatic activity, resulting in reduced phosphorylation of its target acetyl CoA carboxylase. AMPK activators metformin and AICAR partly prevented the cell cycle block, oxidative stress and apoptosis induced by compound C. The small interfering RNA (siRNA) targeting of human AMPK mimicked compound C-induced G(2)/M cell cycle arrest, but failed to induce oxidative stress and apoptosis in U251 glioma cells. In conclusion, our data indicate that AMPK inhibition is required, but not sufficient for compound C-mediated apoptotic death of glioma cells. (c) 2009 Elsevier Inc. All rights reserved.",
journal = "Biochemical Pharmacology",
title = "AMP-activated protein kinase-dependent and -independent mechanisms underlying in vitro antiglioma action of compound C",
volume = "77",
number = "11",
pages = "1684-1693",
doi = "10.1016/j.bcp.2009.03.005"
}

Vucicevic, L., Misirkić, M., Janjetović, K. D., Harhaji-Trajković, L. M., Prica, M., Stevanović, D., Isenović, E. R., Sudar, E., Šumarac-Dumanović, M., Micic, D.,& Trajković, V. S.. (2009). AMP-activated protein kinase-dependent and -independent mechanisms underlying in vitro antiglioma action of compound C. in Biochemical Pharmacology, 77(11), 1684-1693.
https://doi.org/10.1016/j.bcp.2009.03.005

Vucicevic L, Misirkić M, Janjetović KD, Harhaji-Trajković LM, Prica M, Stevanović D, Isenović ER, Sudar E, Šumarac-Dumanović M, Micic D, Trajković VS. AMP-activated protein kinase-dependent and -independent mechanisms underlying in vitro antiglioma action of compound C. in Biochemical Pharmacology. 2009;77(11):1684-1693.
doi:10.1016/j.bcp.2009.03.005 .

Vucicevic, Ljubica, Misirkić, Maja, Janjetović, Kristina D., Harhaji-Trajković, Ljubica M., Prica, Marko, Stevanović, Darko, Isenović, Esma R., Sudar, Emina, Šumarac-Dumanović, Mirjana, Micic, Dragan, Trajković, Vladimir S., "AMP-activated protein kinase-dependent and -independent mechanisms underlying in vitro antiglioma action of compound C" in Biochemical Pharmacology, 77, no. 11 (2009):1684-1693,
https://doi.org/10.1016/j.bcp.2009.03.005 . .