TY  - JOUR
AU  - Stepanović, Ana
AU  - Terzić Jovanović, Nataša
AU  - Korać, Aleksandra
AU  - Zlatović, Mario
AU  - Nikolić, Igor
AU  - Opsenica, Igor
AU  - Pešić, Milica
PY  - 2024
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/6664
AB  - Two novel hybrid compounds, CON1 and CON2, have been developed by combining sclareol (SC) and doxorubicin (DOX) into a single molecular entity. These hybrid compounds have a 1:1 molar ratio of covalently linked SC and DOX. They have demonstrated promising anticancer properties, especially in glioblastoma cells, and have also shown potential in treating multidrug-resistant (MDR) cancer cells that express the P-glycoprotein (P-gp) membrane transporter. CON1 and CON2 form nanoparticles, as confirmed by Zetasizer, transmission electron microscopy (TEM), and chemical modeling. TEM also showed that CON1 and CON2 can be found in glioblastoma cells, specifically in the cytoplasm, different organelles, nucleus, and nucleolus. To examine the anticancer properties, the U87 glioblastoma cell line, and its corresponding multidrug-resistant U87-TxR cell line, as well as patient-derived astrocytoma grade 3 cells (ASC), were used, while normal human lung fibroblasts were used to determine the selectivity. CON1 and CON2 exhibited better resistance and selectivity profiles than DOX, showing less cytotoxicity, as evidenced by real-time cell analysis, DNA damage determination, cell death induction, mitochondrial respiration, and mitochondrial membrane depolarization studies. Cell cycle analysis and the β-galactosidase activity assay suggested that glioblastoma cells die by senescence following CON1 treatment. Overall, CON1 and CON2 showed great potential as they have better anticancer features than DOX. They are promising candidates for additional preclinical and clinical studies on glioblastoma.
PB  - Elsevier Masson SAS
T2  - Biomedicine & Pharmacotherapy
T1  - Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma
VL  - 174
DO  - 10.1016/j.biopha.2024.116496
SP  - 116496
ER  - 

@article{
author = "Stepanović, Ana and Terzić Jovanović, Nataša and Korać, Aleksandra and Zlatović, Mario and Nikolić, Igor and Opsenica, Igor and Pešić, Milica",
year = "2024",
abstract = "Two novel hybrid compounds, CON1 and CON2, have been developed by combining sclareol (SC) and doxorubicin (DOX) into a single molecular entity. These hybrid compounds have a 1:1 molar ratio of covalently linked SC and DOX. They have demonstrated promising anticancer properties, especially in glioblastoma cells, and have also shown potential in treating multidrug-resistant (MDR) cancer cells that express the P-glycoprotein (P-gp) membrane transporter. CON1 and CON2 form nanoparticles, as confirmed by Zetasizer, transmission electron microscopy (TEM), and chemical modeling. TEM also showed that CON1 and CON2 can be found in glioblastoma cells, specifically in the cytoplasm, different organelles, nucleus, and nucleolus. To examine the anticancer properties, the U87 glioblastoma cell line, and its corresponding multidrug-resistant U87-TxR cell line, as well as patient-derived astrocytoma grade 3 cells (ASC), were used, while normal human lung fibroblasts were used to determine the selectivity. CON1 and CON2 exhibited better resistance and selectivity profiles than DOX, showing less cytotoxicity, as evidenced by real-time cell analysis, DNA damage determination, cell death induction, mitochondrial respiration, and mitochondrial membrane depolarization studies. Cell cycle analysis and the β-galactosidase activity assay suggested that glioblastoma cells die by senescence following CON1 treatment. Overall, CON1 and CON2 showed great potential as they have better anticancer features than DOX. They are promising candidates for additional preclinical and clinical studies on glioblastoma.",
publisher = "Elsevier Masson SAS",
journal = "Biomedicine & Pharmacotherapy",
title = "Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma",
volume = "174",
doi = "10.1016/j.biopha.2024.116496",
pages = "116496"
}

Stepanović, A., Terzić Jovanović, N., Korać, A., Zlatović, M., Nikolić, I., Opsenica, I.,& Pešić, M.. (2024). Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma. in Biomedicine & Pharmacotherapy
Elsevier Masson SAS., 174, 116496.
https://doi.org/10.1016/j.biopha.2024.116496

Stepanović A, Terzić Jovanović N, Korać A, Zlatović M, Nikolić I, Opsenica I, Pešić M. Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma. in Biomedicine & Pharmacotherapy. 2024;174:116496.
doi:10.1016/j.biopha.2024.116496 .

Stepanović, Ana, Terzić Jovanović, Nataša, Korać, Aleksandra, Zlatović, Mario, Nikolić, Igor, Opsenica, Igor, Pešić, Milica, "Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma" in Biomedicine & Pharmacotherapy, 174 (2024):116496,
https://doi.org/10.1016/j.biopha.2024.116496 . .

TY  - CONF
AU  - Opsenica, Igor
AU  - Koračak, Ljiljana
AU  - Lupšić, Ema
AU  - Jovanović, Mirna
AU  - Novaković, Miroslav
AU  - Pešić, Milica
PY  - 2023
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/6382
AB  - Derivatization of artemisinin, a natural sesquiterpene lactone, and its synthetic analog artesunate, is of significant interest in medicinal chemistry due to their versatile biological activity, including antimalarial and anticancer. The importance of the pyrimidine scaffold in medicinal chemistry is evidenced by its presence in many natural products and approved drugs, as well as in numerous biologically active compounds.
In this study, we report the synthesis of several novel hybrid molecules comprising two pharmacophores
(artesunic acid and pyrimidine scaffold) and their activity against sensitive and multidrug‐resistant (MDR)
human non‐small cell lung carcinoma (NSCLC) cells. The synthesis of novel artemisinin-pyrimidine hybrid
molecules was accomplished via amide bond formation between artesunic acid and pyrimidine derivatives. A lead compound was identified through structure activity relationship (SAR) studies. Several hybrids were capable of evading the MDR phenotype, increasing the sensitivity of MDR NSCLC cells toward doxorubicin and displayed inhibitory activity against P-glycoprotein.
PB  - Cambridge: Royal Society of Chemistry
C3  - Book of abstracts: 22nd European Symposium on Organic Chemistry Ghent: ESOC23GHENT; 2023 Jul 9-13; Ghent, Belgium
T1  - Synthesis of Novel Artemisinin Derivatives With Potent Anticancer Activities Against Multidrug-resistant Cancer Cells
SP  - 213
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_6382
ER  - 

@conference{
author = "Opsenica, Igor and Koračak, Ljiljana and Lupšić, Ema and Jovanović, Mirna and Novaković, Miroslav and Pešić, Milica",
year = "2023",
abstract = "Derivatization of artemisinin, a natural sesquiterpene lactone, and its synthetic analog artesunate, is of significant interest in medicinal chemistry due to their versatile biological activity, including antimalarial and anticancer. The importance of the pyrimidine scaffold in medicinal chemistry is evidenced by its presence in many natural products and approved drugs, as well as in numerous biologically active compounds.
In this study, we report the synthesis of several novel hybrid molecules comprising two pharmacophores
(artesunic acid and pyrimidine scaffold) and their activity against sensitive and multidrug‐resistant (MDR)
human non‐small cell lung carcinoma (NSCLC) cells. The synthesis of novel artemisinin-pyrimidine hybrid
molecules was accomplished via amide bond formation between artesunic acid and pyrimidine derivatives. A lead compound was identified through structure activity relationship (SAR) studies. Several hybrids were capable of evading the MDR phenotype, increasing the sensitivity of MDR NSCLC cells toward doxorubicin and displayed inhibitory activity against P-glycoprotein.",
publisher = "Cambridge: Royal Society of Chemistry",
journal = "Book of abstracts: 22nd European Symposium on Organic Chemistry Ghent: ESOC23GHENT; 2023 Jul 9-13; Ghent, Belgium",
title = "Synthesis of Novel Artemisinin Derivatives With Potent Anticancer Activities Against Multidrug-resistant Cancer Cells",
pages = "213",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_6382"
}

Opsenica, I., Koračak, L., Lupšić, E., Jovanović, M., Novaković, M.,& Pešić, M.. (2023). Synthesis of Novel Artemisinin Derivatives With Potent Anticancer Activities Against Multidrug-resistant Cancer Cells. in Book of abstracts: 22nd European Symposium on Organic Chemistry Ghent: ESOC23GHENT; 2023 Jul 9-13; Ghent, Belgium
Cambridge: Royal Society of Chemistry., 213.
https://hdl.handle.net/21.15107/rcub_ibiss_6382

Opsenica I, Koračak L, Lupšić E, Jovanović M, Novaković M, Pešić M. Synthesis of Novel Artemisinin Derivatives With Potent Anticancer Activities Against Multidrug-resistant Cancer Cells. in Book of abstracts: 22nd European Symposium on Organic Chemistry Ghent: ESOC23GHENT; 2023 Jul 9-13; Ghent, Belgium. 2023;:213.
https://hdl.handle.net/21.15107/rcub_ibiss_6382 .

Opsenica, Igor, Koračak, Ljiljana, Lupšić, Ema, Jovanović, Mirna, Novaković, Miroslav, Pešić, Milica, "Synthesis of Novel Artemisinin Derivatives With Potent Anticancer Activities Against Multidrug-resistant Cancer Cells" in Book of abstracts: 22nd European Symposium on Organic Chemistry Ghent: ESOC23GHENT; 2023 Jul 9-13; Ghent, Belgium (2023):213,
https://hdl.handle.net/21.15107/rcub_ibiss_6382 .

TY  - CONF
AU  - Stepanović, Ana
AU  - Lupšić, Ema
AU  - Dinić, Jelena
AU  - Podolski-Renić, Ana
AU  - Pajović, Milica
AU  - Jovanović Stojanov, Sofija
AU  - Dragoj, Miodrag
AU  - Terzić Jovanović, Nataša
AU  - Opsenica, Igor
AU  - Pešić, Milica
PY  - 2023
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5905
AB  - Background: Doxorubicin (DOX) has been very effective against glioblastoma in
vitro. Its application in vivo is hampered because it cannot pass the blood–brain
barrier (BBB). Significant research efforts are invested to overcome this limitation.
Sclareol (SC) is an aromatic compound naturally found in clary sage. The
combination of SC and DOX showed promising effects in different tumor types in
vitro and in vivo. Therefore, we tested their combination and innovative hybrid
molecules (SC:DOX) on glioblastoma cells with the expression of P-glycoprotein, a
major component of BBB and cancer multidrug resistance marker. Methods:
Cytotoxicity and selectivity towards glioblastoma cells of SC, DOX, their
combination, and SC:DOX were examined by MTT assay. The effect of SC on DOX
accumulation was determined by flow cytometry. We also studied SC:DOX
accumulation, cellular uptake, localization imaging, and DNA damage induction.
Results: The effects of simultaneous SC and DOX treatments demonstrated the
considerable potential of SC to reverse DOX resistance in glioblastoma cells and
increase DOX accumulation. SC:DOX hybrids, named CON1 and CON2 were less
cytotoxic than DOX, but with reduced resistance and increased selectivity towards
glioblastoma cells. Cellular uptake of CON1 and CON2 was increased in glioblastoma
cells compared to DOX. Perinuclear localization of CON1 and CON2 vs. nuclear
localization of DOX as well as no DNA damaging effects suggest a different
mechanism of action for SC:DOX. Conclusion: The combination of SC and DOX, and
their innovative hybrids, could be considered a promising strategy that can overcome
the limitations of DOX application in glioblastoma.
PB  - Belgrade: Serbian Neuroscience Society
C3  - Book of abstracts: 8th Congress of Serbian neuroscience society with international participation; 2023 May 31 - Jun 2; Belgrade, Serbia
T1  - New anti-glioblastoma strategy with natural compounds sclareol and doxorubicin
SP  - 71
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_5905
ER  - 

@conference{
author = "Stepanović, Ana and Lupšić, Ema and Dinić, Jelena and Podolski-Renić, Ana and Pajović, Milica and Jovanović Stojanov, Sofija and Dragoj, Miodrag and Terzić Jovanović, Nataša and Opsenica, Igor and Pešić, Milica",
year = "2023",
abstract = "Background: Doxorubicin (DOX) has been very effective against glioblastoma in
vitro. Its application in vivo is hampered because it cannot pass the blood–brain
barrier (BBB). Significant research efforts are invested to overcome this limitation.
Sclareol (SC) is an aromatic compound naturally found in clary sage. The
combination of SC and DOX showed promising effects in different tumor types in
vitro and in vivo. Therefore, we tested their combination and innovative hybrid
molecules (SC:DOX) on glioblastoma cells with the expression of P-glycoprotein, a
major component of BBB and cancer multidrug resistance marker. Methods:
Cytotoxicity and selectivity towards glioblastoma cells of SC, DOX, their
combination, and SC:DOX were examined by MTT assay. The effect of SC on DOX
accumulation was determined by flow cytometry. We also studied SC:DOX
accumulation, cellular uptake, localization imaging, and DNA damage induction.
Results: The effects of simultaneous SC and DOX treatments demonstrated the
considerable potential of SC to reverse DOX resistance in glioblastoma cells and
increase DOX accumulation. SC:DOX hybrids, named CON1 and CON2 were less
cytotoxic than DOX, but with reduced resistance and increased selectivity towards
glioblastoma cells. Cellular uptake of CON1 and CON2 was increased in glioblastoma
cells compared to DOX. Perinuclear localization of CON1 and CON2 vs. nuclear
localization of DOX as well as no DNA damaging effects suggest a different
mechanism of action for SC:DOX. Conclusion: The combination of SC and DOX, and
their innovative hybrids, could be considered a promising strategy that can overcome
the limitations of DOX application in glioblastoma.",
publisher = "Belgrade: Serbian Neuroscience Society",
journal = "Book of abstracts: 8th Congress of Serbian neuroscience society with international participation; 2023 May 31 - Jun 2; Belgrade, Serbia",
title = "New anti-glioblastoma strategy with natural compounds sclareol and doxorubicin",
pages = "71",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_5905"
}

Stepanović, A., Lupšić, E., Dinić, J., Podolski-Renić, A., Pajović, M., Jovanović Stojanov, S., Dragoj, M., Terzić Jovanović, N., Opsenica, I.,& Pešić, M.. (2023). New anti-glioblastoma strategy with natural compounds sclareol and doxorubicin. in Book of abstracts: 8th Congress of Serbian neuroscience society with international participation; 2023 May 31 - Jun 2; Belgrade, Serbia
Belgrade: Serbian Neuroscience Society., 71.
https://hdl.handle.net/21.15107/rcub_ibiss_5905

Stepanović A, Lupšić E, Dinić J, Podolski-Renić A, Pajović M, Jovanović Stojanov S, Dragoj M, Terzić Jovanović N, Opsenica I, Pešić M. New anti-glioblastoma strategy with natural compounds sclareol and doxorubicin. in Book of abstracts: 8th Congress of Serbian neuroscience society with international participation; 2023 May 31 - Jun 2; Belgrade, Serbia. 2023;:71.
https://hdl.handle.net/21.15107/rcub_ibiss_5905 .

Stepanović, Ana, Lupšić, Ema, Dinić, Jelena, Podolski-Renić, Ana, Pajović, Milica, Jovanović Stojanov, Sofija, Dragoj, Miodrag, Terzić Jovanović, Nataša, Opsenica, Igor, Pešić, Milica, "New anti-glioblastoma strategy with natural compounds sclareol and doxorubicin" in Book of abstracts: 8th Congress of Serbian neuroscience society with international participation; 2023 May 31 - Jun 2; Belgrade, Serbia (2023):71,
https://hdl.handle.net/21.15107/rcub_ibiss_5905 .

TY  - JOUR
AU  - Koračak, Ljiljana
AU  - Lupšić, Ema
AU  - Terzić Jovanović, Nataša
AU  - Jovanović, Mirna
AU  - Novaković, Miroslav
AU  - Nedialkov, Paraskev
AU  - Trendafilova, Antoaneta
AU  - Zlatović, Mario
AU  - Pešić, Milica
AU  - Opsenica, Igor
PY  - 2023
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5890
AB  - The synthesis of 17 hybrid molecules, consisting of artesunate, a derivative of naturally occurring artemisinin, and synthetic 4-aryl-2-aminopyrimidines, is described. New compounds were designed to improve the parent compounds' cytotoxic properties, activity, and selectivity. The synthesized hybrid molecules (15a–f with ethylenediamine linker and 16a–k with piperazine linker), as well as their precursors – pyrimidine derivatives (13a–f and 14a–k), artemisinin, and artesunate, were tested on sensitive and multidrug-resistant (MDR) human non-small cell lung carcinoma (NSCLC) cells. All hybrid compounds with piperazine linker 16a–k were selective toward NSCLC cells and displayed IC50 values below 5 μM. Although they showed similar anticancer potency as artesunate, their selectivity against cancer cells was considerably improved. Importantly, 16h–k hybrid compounds were able to evade MDR phenotype, inhibit P-glycoprotein (P-gp) activity, and increase the sensitivity of MDR NSCLC cells to doxorubicin (DOX). The inhibition of P-gp activity induced by 16h–j was stronger than the one obtained with artesunate. Among these four hybrid compounds, 16k was the most potent anticancer agent with similar IC50 values of around 1.5 μM (for comparison – over 3.1 μM for artesunate) in sensitive and MDR NSCLC cells.
PB  - Cambridge: Royal Society of Chemistry
T2  - New Journal of Chemistry
T1  - Novel artesunate–pyrimidine-based hybrids with anticancer potential against multidrug-resistant cancer cells
IS  - 14
VL  - 47
DO  - 10.1039/D3NJ00427A
SP  - 6844
EP  - 6855
ER  - 

@article{
author = "Koračak, Ljiljana and Lupšić, Ema and Terzić Jovanović, Nataša and Jovanović, Mirna and Novaković, Miroslav and Nedialkov, Paraskev and Trendafilova, Antoaneta and Zlatović, Mario and Pešić, Milica and Opsenica, Igor",
year = "2023",
abstract = "The synthesis of 17 hybrid molecules, consisting of artesunate, a derivative of naturally occurring artemisinin, and synthetic 4-aryl-2-aminopyrimidines, is described. New compounds were designed to improve the parent compounds' cytotoxic properties, activity, and selectivity. The synthesized hybrid molecules (15a–f with ethylenediamine linker and 16a–k with piperazine linker), as well as their precursors – pyrimidine derivatives (13a–f and 14a–k), artemisinin, and artesunate, were tested on sensitive and multidrug-resistant (MDR) human non-small cell lung carcinoma (NSCLC) cells. All hybrid compounds with piperazine linker 16a–k were selective toward NSCLC cells and displayed IC50 values below 5 μM. Although they showed similar anticancer potency as artesunate, their selectivity against cancer cells was considerably improved. Importantly, 16h–k hybrid compounds were able to evade MDR phenotype, inhibit P-glycoprotein (P-gp) activity, and increase the sensitivity of MDR NSCLC cells to doxorubicin (DOX). The inhibition of P-gp activity induced by 16h–j was stronger than the one obtained with artesunate. Among these four hybrid compounds, 16k was the most potent anticancer agent with similar IC50 values of around 1.5 μM (for comparison – over 3.1 μM for artesunate) in sensitive and MDR NSCLC cells.",
publisher = "Cambridge: Royal Society of Chemistry",
journal = "New Journal of Chemistry",
title = "Novel artesunate–pyrimidine-based hybrids with anticancer potential against multidrug-resistant cancer cells",
number = "14",
volume = "47",
doi = "10.1039/D3NJ00427A",
pages = "6844-6855"
}

Koračak, L., Lupšić, E., Terzić Jovanović, N., Jovanović, M., Novaković, M., Nedialkov, P., Trendafilova, A., Zlatović, M., Pešić, M.,& Opsenica, I.. (2023). Novel artesunate–pyrimidine-based hybrids with anticancer potential against multidrug-resistant cancer cells. in New Journal of Chemistry
Cambridge: Royal Society of Chemistry., 47(14), 6844-6855.
https://doi.org/10.1039/D3NJ00427A

Koračak L, Lupšić E, Terzić Jovanović N, Jovanović M, Novaković M, Nedialkov P, Trendafilova A, Zlatović M, Pešić M, Opsenica I. Novel artesunate–pyrimidine-based hybrids with anticancer potential against multidrug-resistant cancer cells. in New Journal of Chemistry. 2023;47(14):6844-6855.
doi:10.1039/D3NJ00427A .

Koračak, Ljiljana, Lupšić, Ema, Terzić Jovanović, Nataša, Jovanović, Mirna, Novaković, Miroslav, Nedialkov, Paraskev, Trendafilova, Antoaneta, Zlatović, Mario, Pešić, Milica, Opsenica, Igor, "Novel artesunate–pyrimidine-based hybrids with anticancer potential against multidrug-resistant cancer cells" in New Journal of Chemistry, 47, no. 14 (2023):6844-6855,
https://doi.org/10.1039/D3NJ00427A . .

TY  - CONF
AU  - Stojković, Pavle
AU  - Stepanović, Ana
AU  - Terzić Jovanović, Nataša
AU  - Novaković, Miroslav
AU  - Trendafilova, Antoaneta
AU  - Pešić, Milica
AU  - Opsenica, Igor M.
PY  - 2022
UR  - https://euchems2022.eu/images/abstracts.pdf
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5372
AB  - Sclareol is a labdane diterpenoid found in clary sage (Salvia sclarea L.) with various biological activities,
most notably anticancer and cytotoxic activity [1]. There are several examples of synthetic derivatives
of sclareol with antischistosomal [2], antifungal [3], and anticancer activity [4]. Since it is known that
modifications of biologically active molecules can lead to the improvement of physicochemical
properties and modes of interactions with target cells, we have envisioned the derivatization of sclareol
to obtain molecules with more potent cytotoxic activity.
Sclareol used as a starting material in this research was isolated from Clary sage harvested in Bulgaria.
New compounds were obtained by derivatization of sclareol at its Δ14,15 double bond using oxidative
Heck coupling catalyzed by palladium-acetate with copper(II)-acetate as oxidant, followed by the
introduction of different diamine-moieties. Finally, the terminal amino-group was coupled with a
nitrogen-rich heterocycle to obtain desired compounds. During the course of the synthesis, both tertiary
and tertiary allylic hydroxyl groups remained unchanged, which was of particular interest, since it was
shown that the tertiary allylic group is crucial for the biological activity of sclareol.
Synthesized compounds were tested on human cancer cell lines, primarily glioblastoma cells. It was
shown that certain derivatives have caused a significant reduction of glioblastoma cell viability at low
concentrations. Moreover, some derivatives inhibited cell membrane transporter P-glycoprotein (P-gp)
responsible for multidrug resistance and increased accumulation of doxorubicin to the same extent as
tariquidar (a well-known P-gp inhibitor). Most importantly, novel molecules exhibited more potent
biological activity than sclareol itself.
PB  - Sociedade Portuguesa de Química
C3  - Abstract Book: 8th EuChemS Chemistry Congress; 2022 Aug 28 - Sep 1; Lisbon, Portugal
T1  - Synthesis of novel sclareol derivatives and evaluation of their anticancer activity
SP  - 604
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_5372
ER  - 

@conference{
author = "Stojković, Pavle and Stepanović, Ana and Terzić Jovanović, Nataša and Novaković, Miroslav and Trendafilova, Antoaneta and Pešić, Milica and Opsenica, Igor M.",
year = "2022",
abstract = "Sclareol is a labdane diterpenoid found in clary sage (Salvia sclarea L.) with various biological activities,
most notably anticancer and cytotoxic activity [1]. There are several examples of synthetic derivatives
of sclareol with antischistosomal [2], antifungal [3], and anticancer activity [4]. Since it is known that
modifications of biologically active molecules can lead to the improvement of physicochemical
properties and modes of interactions with target cells, we have envisioned the derivatization of sclareol
to obtain molecules with more potent cytotoxic activity.
Sclareol used as a starting material in this research was isolated from Clary sage harvested in Bulgaria.
New compounds were obtained by derivatization of sclareol at its Δ14,15 double bond using oxidative
Heck coupling catalyzed by palladium-acetate with copper(II)-acetate as oxidant, followed by the
introduction of different diamine-moieties. Finally, the terminal amino-group was coupled with a
nitrogen-rich heterocycle to obtain desired compounds. During the course of the synthesis, both tertiary
and tertiary allylic hydroxyl groups remained unchanged, which was of particular interest, since it was
shown that the tertiary allylic group is crucial for the biological activity of sclareol.
Synthesized compounds were tested on human cancer cell lines, primarily glioblastoma cells. It was
shown that certain derivatives have caused a significant reduction of glioblastoma cell viability at low
concentrations. Moreover, some derivatives inhibited cell membrane transporter P-glycoprotein (P-gp)
responsible for multidrug resistance and increased accumulation of doxorubicin to the same extent as
tariquidar (a well-known P-gp inhibitor). Most importantly, novel molecules exhibited more potent
biological activity than sclareol itself.",
publisher = "Sociedade Portuguesa de Química",
journal = "Abstract Book: 8th EuChemS Chemistry Congress; 2022 Aug 28 - Sep 1; Lisbon, Portugal",
title = "Synthesis of novel sclareol derivatives and evaluation of their anticancer activity",
pages = "604",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_5372"
}

Stojković, P., Stepanović, A., Terzić Jovanović, N., Novaković, M., Trendafilova, A., Pešić, M.,& Opsenica, I. M.. (2022). Synthesis of novel sclareol derivatives and evaluation of their anticancer activity. in Abstract Book: 8th EuChemS Chemistry Congress; 2022 Aug 28 - Sep 1; Lisbon, Portugal
Sociedade Portuguesa de Química., 604.
https://hdl.handle.net/21.15107/rcub_ibiss_5372

Stojković P, Stepanović A, Terzić Jovanović N, Novaković M, Trendafilova A, Pešić M, Opsenica IM. Synthesis of novel sclareol derivatives and evaluation of their anticancer activity. in Abstract Book: 8th EuChemS Chemistry Congress; 2022 Aug 28 - Sep 1; Lisbon, Portugal. 2022;:604.
https://hdl.handle.net/21.15107/rcub_ibiss_5372 .

Stojković, Pavle, Stepanović, Ana, Terzić Jovanović, Nataša, Novaković, Miroslav, Trendafilova, Antoaneta, Pešić, Milica, Opsenica, Igor M., "Synthesis of novel sclareol derivatives and evaluation of their anticancer activity" in Abstract Book: 8th EuChemS Chemistry Congress; 2022 Aug 28 - Sep 1; Lisbon, Portugal (2022):604,
https://hdl.handle.net/21.15107/rcub_ibiss_5372 .

TY  - CONF
AU  - Stepanović, Ana
AU  - Stojković, Pavle
AU  - Terzić Jovanović, Nataša
AU  - Novaković, Miroslav
AU  - Opsenica, Igor M.
AU  - Pešić, Milica
PY  - 2022
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5370
AB  - Background: Natural products exhibit a wide range of biological activities and they are starting point in the drug discovery process. Sclareol (SCL) naturally occurring labdane diterpene isolated from Clary sage (Salvia sclarea L.) shows diverse biological properties such as antioxidative, antimicrobial, anti-inflammatory, and anticancer activities. It is well established that fusing two pharmacophores can lead to significant improvement in the biological potential of the molecule by modifying its physicochemical properties. We envisioned that chimeric molecules synthesized by linking triazolo[1,5-a]pyrimidine pharmacophore to SCL would have more potent anticancer activity than their parental compound – SCL. Therefore, the cytotoxic potential of a series of SCL derivatives was compared with SCL. We have also studied their potential to increase the accumulation of substrates of membrane transporter which causes resistance of cancer cells – P-glycoprotein (P-gp). Methods: Cytotoxic potential, selectivity towards cancer cells, and resistance profile of SCL and its derivatives were examined by MTT assay after 72 h exposure in human glioblastoma cells (sensitive U87 and multidrug-resistant U87-TxR) and rat microglial cells (BV-2). We also investigated the effect of SCL and its derivatives on P-gp activity in U87-TxR resistant cells by determining the level of accumulated P-gp substrates (rhodamine 123 and doxorubicin) by flow cytometry. Results: More than half of the tested SCL derivatives considerably reduced glioblastoma cell viability with a concentration of 5 μM. Tested compounds evaded the resistance of glioblastoma cells showing similar or better activity against U87-TxR cells in comparison with U87 cells. All compounds significantly increased the accumulation of rhodamine 123 pointing to the inhibition of P-gp. However, only three of them increased the accumulation of doxorubicin likewise tariquidar, a well-known third-generation P-gp inhibitor, implying that these three SCL derivatives can be valuable as chemo-sensitizing agents. Conclusion: Our results showed that SCL derivatives can be considered as modulators of P-gp activity especially pointing to several lead compounds whose detailed molecular mechanism of anticancer action should be studied.
PB  - STRATAGEM COST Action
C3  - Abstract Book: STRATAGEM’s 5th Annual Meeting: New Diagnostic and Therapeutic Tools against Multidrug Resistant Tumours; 2022 Jun 29 - Jul 1; Coimbra, Portugal
T1  - Hybrids of sclareol and 1,2,4-triazolo[1,5-a]pyrimidine inhibit P-glycoprotein function in glioblastoma cells
SP  - 81
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_5370
ER  - 

@conference{
author = "Stepanović, Ana and Stojković, Pavle and Terzić Jovanović, Nataša and Novaković, Miroslav and Opsenica, Igor M. and Pešić, Milica",
year = "2022",
abstract = "Background: Natural products exhibit a wide range of biological activities and they are starting point in the drug discovery process. Sclareol (SCL) naturally occurring labdane diterpene isolated from Clary sage (Salvia sclarea L.) shows diverse biological properties such as antioxidative, antimicrobial, anti-inflammatory, and anticancer activities. It is well established that fusing two pharmacophores can lead to significant improvement in the biological potential of the molecule by modifying its physicochemical properties. We envisioned that chimeric molecules synthesized by linking triazolo[1,5-a]pyrimidine pharmacophore to SCL would have more potent anticancer activity than their parental compound – SCL. Therefore, the cytotoxic potential of a series of SCL derivatives was compared with SCL. We have also studied their potential to increase the accumulation of substrates of membrane transporter which causes resistance of cancer cells – P-glycoprotein (P-gp). Methods: Cytotoxic potential, selectivity towards cancer cells, and resistance profile of SCL and its derivatives were examined by MTT assay after 72 h exposure in human glioblastoma cells (sensitive U87 and multidrug-resistant U87-TxR) and rat microglial cells (BV-2). We also investigated the effect of SCL and its derivatives on P-gp activity in U87-TxR resistant cells by determining the level of accumulated P-gp substrates (rhodamine 123 and doxorubicin) by flow cytometry. Results: More than half of the tested SCL derivatives considerably reduced glioblastoma cell viability with a concentration of 5 μM. Tested compounds evaded the resistance of glioblastoma cells showing similar or better activity against U87-TxR cells in comparison with U87 cells. All compounds significantly increased the accumulation of rhodamine 123 pointing to the inhibition of P-gp. However, only three of them increased the accumulation of doxorubicin likewise tariquidar, a well-known third-generation P-gp inhibitor, implying that these three SCL derivatives can be valuable as chemo-sensitizing agents. Conclusion: Our results showed that SCL derivatives can be considered as modulators of P-gp activity especially pointing to several lead compounds whose detailed molecular mechanism of anticancer action should be studied.",
publisher = "STRATAGEM COST Action",
journal = "Abstract Book: STRATAGEM’s 5th Annual Meeting: New Diagnostic and Therapeutic Tools against Multidrug Resistant Tumours; 2022 Jun 29 - Jul 1; Coimbra, Portugal",
title = "Hybrids of sclareol and 1,2,4-triazolo[1,5-a]pyrimidine inhibit P-glycoprotein function in glioblastoma cells",
pages = "81",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_5370"
}

Stepanović, A., Stojković, P., Terzić Jovanović, N., Novaković, M., Opsenica, I. M.,& Pešić, M.. (2022). Hybrids of sclareol and 1,2,4-triazolo[1,5-a]pyrimidine inhibit P-glycoprotein function in glioblastoma cells. in Abstract Book: STRATAGEM’s 5th Annual Meeting: New Diagnostic and Therapeutic Tools against Multidrug Resistant Tumours; 2022 Jun 29 - Jul 1; Coimbra, Portugal
STRATAGEM COST Action., 81.
https://hdl.handle.net/21.15107/rcub_ibiss_5370

Stepanović A, Stojković P, Terzić Jovanović N, Novaković M, Opsenica IM, Pešić M. Hybrids of sclareol and 1,2,4-triazolo[1,5-a]pyrimidine inhibit P-glycoprotein function in glioblastoma cells. in Abstract Book: STRATAGEM’s 5th Annual Meeting: New Diagnostic and Therapeutic Tools against Multidrug Resistant Tumours; 2022 Jun 29 - Jul 1; Coimbra, Portugal. 2022;:81.
https://hdl.handle.net/21.15107/rcub_ibiss_5370 .

Stepanović, Ana, Stojković, Pavle, Terzić Jovanović, Nataša, Novaković, Miroslav, Opsenica, Igor M., Pešić, Milica, "Hybrids of sclareol and 1,2,4-triazolo[1,5-a]pyrimidine inhibit P-glycoprotein function in glioblastoma cells" in Abstract Book: STRATAGEM’s 5th Annual Meeting: New Diagnostic and Therapeutic Tools against Multidrug Resistant Tumours; 2022 Jun 29 - Jul 1; Coimbra, Portugal (2022):81,
https://hdl.handle.net/21.15107/rcub_ibiss_5370 .

TY  - CONF
AU  - Stepanović, Ana
AU  - Lupšić, Ema
AU  - Stojković, Pavle
AU  - Dragoj, Miodrag
AU  - Jovanović Stojanov, Sofija
AU  - Terzić- Jovanović, Nataša
AU  - Novaković, Miroslav
AU  - Opsenica, Igor M.
AU  - Pešić, Milica
PY  - 2021
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/4995
AB  - Background: Glioblastoma is the most common, aggressive and lethal brain tumor in adults with high proliferation rate, infiltrating nature and presence of multidrug resistance (MDR). Sclareol (SC) is a naturally occurring labdane type diterpene, derived from Salvia sclarea. We examined cell growth inhibition effect of SC and its derivatives (PAS and TNT groups of compounds) - hybrid (chimeric) molecules. Sclareol was covalently bonded to [1,2,4]triazolo[1,5-a]pyrimidin-7-amine scaffold, and different diamines were used as linkers. We also studied SC potential to reverse DOX resistance and its accumulation. The combination of SC with DOX has been earlier described to potentiate DOX cytotoxicity if simultaneously delivered in nanoparticles. Material and Methods: SC in combination with DOX as well as SC derivatives were tested on human glioma cell line U87, and its MDR counterpart - U87-TxR. MTT assay was used to examine inhibition of cell growth. Accumulation of DOX was measured by flow cytometry. Results: Thirteen out of nineteen TNT derivatives and three out of six PAS derivatives showed stronger anti-glioma effect than SC. Simultaneous treatment of SC with DOX demonstrated potential of SC to reverse DOX resistance. Even more, SC significantly increased DOX accumulation in both glioblastoma cell lines. Conclusion: Results obtained in this study showed a considerable synergy of SC and DOX in glioma cells. Better results observed with SC derivatives make them good candidates for further testing.
PB  - Belgrade: Serbian Association for Cancer Research
C3  - Abstract book: The fifth congress of the Serbian association for cancer research:“Translational potential of cancer research in Serbia“; 2021 Dec 3; Virtual.
T1  - Anticancer effects of sclareol and its derivatives in glioblastoma cells
SP  - 72
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_4995
ER  - 

@conference{
author = "Stepanović, Ana and Lupšić, Ema and Stojković, Pavle and Dragoj, Miodrag and Jovanović Stojanov, Sofija and Terzić- Jovanović, Nataša and Novaković, Miroslav and Opsenica, Igor M. and Pešić, Milica",
year = "2021",
abstract = "Background: Glioblastoma is the most common, aggressive and lethal brain tumor in adults with high proliferation rate, infiltrating nature and presence of multidrug resistance (MDR). Sclareol (SC) is a naturally occurring labdane type diterpene, derived from Salvia sclarea. We examined cell growth inhibition effect of SC and its derivatives (PAS and TNT groups of compounds) - hybrid (chimeric) molecules. Sclareol was covalently bonded to [1,2,4]triazolo[1,5-a]pyrimidin-7-amine scaffold, and different diamines were used as linkers. We also studied SC potential to reverse DOX resistance and its accumulation. The combination of SC with DOX has been earlier described to potentiate DOX cytotoxicity if simultaneously delivered in nanoparticles. Material and Methods: SC in combination with DOX as well as SC derivatives were tested on human glioma cell line U87, and its MDR counterpart - U87-TxR. MTT assay was used to examine inhibition of cell growth. Accumulation of DOX was measured by flow cytometry. Results: Thirteen out of nineteen TNT derivatives and three out of six PAS derivatives showed stronger anti-glioma effect than SC. Simultaneous treatment of SC with DOX demonstrated potential of SC to reverse DOX resistance. Even more, SC significantly increased DOX accumulation in both glioblastoma cell lines. Conclusion: Results obtained in this study showed a considerable synergy of SC and DOX in glioma cells. Better results observed with SC derivatives make them good candidates for further testing.",
publisher = "Belgrade: Serbian Association for Cancer Research",
journal = "Abstract book: The fifth congress of the Serbian association for cancer research:“Translational potential of cancer research in Serbia“; 2021 Dec 3; Virtual.",
title = "Anticancer effects of sclareol and its derivatives in glioblastoma cells",
pages = "72",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_4995"
}

Stepanović, A., Lupšić, E., Stojković, P., Dragoj, M., Jovanović Stojanov, S., Terzić- Jovanović, N., Novaković, M., Opsenica, I. M.,& Pešić, M.. (2021). Anticancer effects of sclareol and its derivatives in glioblastoma cells. in Abstract book: The fifth congress of the Serbian association for cancer research:“Translational potential of cancer research in Serbia“; 2021 Dec 3; Virtual.
Belgrade: Serbian Association for Cancer Research., 72.
https://hdl.handle.net/21.15107/rcub_ibiss_4995

Stepanović A, Lupšić E, Stojković P, Dragoj M, Jovanović Stojanov S, Terzić- Jovanović N, Novaković M, Opsenica IM, Pešić M. Anticancer effects of sclareol and its derivatives in glioblastoma cells. in Abstract book: The fifth congress of the Serbian association for cancer research:“Translational potential of cancer research in Serbia“; 2021 Dec 3; Virtual.. 2021;:72.
https://hdl.handle.net/21.15107/rcub_ibiss_4995 .

Stepanović, Ana, Lupšić, Ema, Stojković, Pavle, Dragoj, Miodrag, Jovanović Stojanov, Sofija, Terzić- Jovanović, Nataša, Novaković, Miroslav, Opsenica, Igor M., Pešić, Milica, "Anticancer effects of sclareol and its derivatives in glioblastoma cells" in Abstract book: The fifth congress of the Serbian association for cancer research:“Translational potential of cancer research in Serbia“; 2021 Dec 3; Virtual. (2021):72,
https://hdl.handle.net/21.15107/rcub_ibiss_4995 .

TY  - CONF
AU  - Stepanović, Ana
AU  - Lupšić, Ema
AU  - Nikolić, Andrea M.
AU  - Dragoj, Miodrag
AU  - Jovanović Stojanov, Sofija
AU  - Novaković, Miroslav
AU  - Opsenica, Igor M.
AU  - Pešić, Milica
PY  - 2021
UR  - http://www.bds.org.rs/download/SBS_Conference_10_2021.pdf
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5607
AB  - P-glycoprotein (P-gp) is often expressed at the cellular membrane of cancer cells where it plays a significant role in protecting cancer cells from extracellular assault. It works as an export transporter for many substrates - xenobiotics including chemotherapeutics. Several generations of P-gp inhibitors have been developed and studied but they have not yet been introduced into clinics. The most promising fourth-generation comprises natural compounds. In this study, we evaluated the potential of sclareol, a naturally occurring labdane diterpene, to inhibit P-gp activity in human glioblastoma (U87, and its resistant variant U87-TxR with P-gp overexpression) and non-small cell lung carcinoma (NCI-H460, and its resistant variant NCI-H460/R with P-gp overexpression) cell lines. To that end, we used the accumulation assays of fluorescent P-gp substrates (rhodamine 123 and doxorubicin) that were analyzed by flow cytometry. An increase in the accumulation of the P-gp substrate corresponds to the level of P-gp activity suppression. Our results showed that simultaneous application of sclareol (20 μM and 50 μM) with either rhodamine 123 (5 μM) or doxorubicin (20 μM) significantly increased their accumulation in resistant cells (U87-TxR and NCI-H460/R) than in their corresponding sensitive cells (U87 and NCI-H460). The doxorubicin accumulation was also considerably increased in sensitive U87 cells implying that sclareol may interact with doxorubicin through other mechanisms in glioblastoma cells (not only by P-gp inhibition). Further investigations are envisioned to reveal the mechanisms behind sclareol and doxorubicin interaction in glioblastoma cells.
PB  - Belgrade: Faculty of Chemistry: Serbian Biochemical Society, 2021
C3  - Serbian Biochemical Society Tenth Conference: with international participation: Biochemical Insights into Molecular Mechanisms; 2021 Sep 24; Kragujevac, Serbia
T1  - Sclareol, a natural compound, inhibits P-glycoprotein activity in cancer cells
SP  - 77
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_5607
ER  - 

@conference{
author = "Stepanović, Ana and Lupšić, Ema and Nikolić, Andrea M. and Dragoj, Miodrag and Jovanović Stojanov, Sofija and Novaković, Miroslav and Opsenica, Igor M. and Pešić, Milica",
year = "2021",
abstract = "P-glycoprotein (P-gp) is often expressed at the cellular membrane of cancer cells where it plays a significant role in protecting cancer cells from extracellular assault. It works as an export transporter for many substrates - xenobiotics including chemotherapeutics. Several generations of P-gp inhibitors have been developed and studied but they have not yet been introduced into clinics. The most promising fourth-generation comprises natural compounds. In this study, we evaluated the potential of sclareol, a naturally occurring labdane diterpene, to inhibit P-gp activity in human glioblastoma (U87, and its resistant variant U87-TxR with P-gp overexpression) and non-small cell lung carcinoma (NCI-H460, and its resistant variant NCI-H460/R with P-gp overexpression) cell lines. To that end, we used the accumulation assays of fluorescent P-gp substrates (rhodamine 123 and doxorubicin) that were analyzed by flow cytometry. An increase in the accumulation of the P-gp substrate corresponds to the level of P-gp activity suppression. Our results showed that simultaneous application of sclareol (20 μM and 50 μM) with either rhodamine 123 (5 μM) or doxorubicin (20 μM) significantly increased their accumulation in resistant cells (U87-TxR and NCI-H460/R) than in their corresponding sensitive cells (U87 and NCI-H460). The doxorubicin accumulation was also considerably increased in sensitive U87 cells implying that sclareol may interact with doxorubicin through other mechanisms in glioblastoma cells (not only by P-gp inhibition). Further investigations are envisioned to reveal the mechanisms behind sclareol and doxorubicin interaction in glioblastoma cells.",
publisher = "Belgrade: Faculty of Chemistry: Serbian Biochemical Society, 2021",
journal = "Serbian Biochemical Society Tenth Conference: with international participation: Biochemical Insights into Molecular Mechanisms; 2021 Sep 24; Kragujevac, Serbia",
title = "Sclareol, a natural compound, inhibits P-glycoprotein activity in cancer cells",
pages = "77",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_5607"
}

Stepanović, A., Lupšić, E., Nikolić, A. M., Dragoj, M., Jovanović Stojanov, S., Novaković, M., Opsenica, I. M.,& Pešić, M.. (2021). Sclareol, a natural compound, inhibits P-glycoprotein activity in cancer cells. in Serbian Biochemical Society Tenth Conference: with international participation: Biochemical Insights into Molecular Mechanisms; 2021 Sep 24; Kragujevac, Serbia
Belgrade: Faculty of Chemistry: Serbian Biochemical Society, 2021., 77.
https://hdl.handle.net/21.15107/rcub_ibiss_5607

Stepanović A, Lupšić E, Nikolić AM, Dragoj M, Jovanović Stojanov S, Novaković M, Opsenica IM, Pešić M. Sclareol, a natural compound, inhibits P-glycoprotein activity in cancer cells. in Serbian Biochemical Society Tenth Conference: with international participation: Biochemical Insights into Molecular Mechanisms; 2021 Sep 24; Kragujevac, Serbia. 2021;:77.
https://hdl.handle.net/21.15107/rcub_ibiss_5607 .

Stepanović, Ana, Lupšić, Ema, Nikolić, Andrea M., Dragoj, Miodrag, Jovanović Stojanov, Sofija, Novaković, Miroslav, Opsenica, Igor M., Pešić, Milica, "Sclareol, a natural compound, inhibits P-glycoprotein activity in cancer cells" in Serbian Biochemical Society Tenth Conference: with international participation: Biochemical Insights into Molecular Mechanisms; 2021 Sep 24; Kragujevac, Serbia (2021):77,
https://hdl.handle.net/21.15107/rcub_ibiss_5607 .