Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens
The Western Ghats, India, is a hotspot for lichen diversity. However, the pharmacological importance of lichen-associated metabolites remains untapped. This study aimed to evaluate the cytotoxic potential of lichens of this region. For this, sixteen macrolichens were collected and identified from tw...
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MDPI AG
2023-01-01
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| Series: | Plants |
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| Online Access: | https://www.mdpi.com/2223-7747/12/3/519 |
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| author | Madhuree Kumari Siya Kamat Sandeep Kumar Singh Ajay Kumar C. Jayabaskaran |
| author_facet | Madhuree Kumari Siya Kamat Sandeep Kumar Singh Ajay Kumar C. Jayabaskaran |
| author_sort | Madhuree Kumari |
| collection | DOAJ |
| description | The Western Ghats, India, is a hotspot for lichen diversity. However, the pharmacological importance of lichen-associated metabolites remains untapped. This study aimed to evaluate the cytotoxic potential of lichens of this region. For this, sixteen macrolichens were collected and identified from two locations in the Western Ghats. The acetone extract of <i>Usnea cornuta</i> (UC2A) showed significant cytotoxicity towards multiple human cancer cell lines. Interestingly, co-treatment with chloroquine (CQ), an autophagy inhibitor, increased the cytotoxic potential of the UC2A extract. A gas chromatography mass spectrometry (GCMS) study revealed usnic acid (UA), atraric acid and barbatic acid as the dominant cytotoxic compounds in the UC2A extract. Further, UA was purified and identified from the UC2A extract and evaluated for cytotoxicity in HeLa cells. The monodansyl cadaverine and mitotracker red double staining revealed the autophagy-inducing activities of UA, and the inhibition of autophagy was confirmed via CQ treatment. Autophagy inhibition increased the cytotoxicity of UA by 12–16% in a concentration-dependent manner. It also increased lipid peroxidation, ROS levels and mitochondrial depolarization and decreased glutathione availability. A decrease in zeta potential and a 40% increase in caspase 3/7 activity were also noted after CQ treatment of UA-treated cells. Thus, cytotoxicity of UA can be increased by inhibiting autophagy. |
| first_indexed | 2024-03-11T09:29:28Z |
| format | Article |
| id | doaj.art-772aa95dcf4e4b039eeab68ff634ffb0 |
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| issn | 2223-7747 |
| language | English |
| last_indexed | 2024-03-11T09:29:28Z |
| publishDate | 2023-01-01 |
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| spelling | doaj.art-772aa95dcf4e4b039eeab68ff634ffb02023-11-16T17:43:30ZengMDPI AGPlants2223-77472023-01-0112351910.3390/plants12030519Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from LichensMadhuree Kumari0Siya Kamat1Sandeep Kumar Singh2Ajay Kumar3C. Jayabaskaran4Department of Biochemistry, Indian Institute of Science, Bangalore 560012, IndiaDepartment of Biochemistry, Indian Institute of Science, Bangalore 560012, IndiaDivision of Microbiology, Indian Agricultural Research Institute, Pusa, New Delhi 110012, IndiaCentre of Advanced study in Botany, Banaras Hindu University, Varanasi 221005, IndiaDepartment of Biochemistry, Indian Institute of Science, Bangalore 560012, IndiaThe Western Ghats, India, is a hotspot for lichen diversity. However, the pharmacological importance of lichen-associated metabolites remains untapped. This study aimed to evaluate the cytotoxic potential of lichens of this region. For this, sixteen macrolichens were collected and identified from two locations in the Western Ghats. The acetone extract of <i>Usnea cornuta</i> (UC2A) showed significant cytotoxicity towards multiple human cancer cell lines. Interestingly, co-treatment with chloroquine (CQ), an autophagy inhibitor, increased the cytotoxic potential of the UC2A extract. A gas chromatography mass spectrometry (GCMS) study revealed usnic acid (UA), atraric acid and barbatic acid as the dominant cytotoxic compounds in the UC2A extract. Further, UA was purified and identified from the UC2A extract and evaluated for cytotoxicity in HeLa cells. The monodansyl cadaverine and mitotracker red double staining revealed the autophagy-inducing activities of UA, and the inhibition of autophagy was confirmed via CQ treatment. Autophagy inhibition increased the cytotoxicity of UA by 12–16% in a concentration-dependent manner. It also increased lipid peroxidation, ROS levels and mitochondrial depolarization and decreased glutathione availability. A decrease in zeta potential and a 40% increase in caspase 3/7 activity were also noted after CQ treatment of UA-treated cells. Thus, cytotoxicity of UA can be increased by inhibiting autophagy.https://www.mdpi.com/2223-7747/12/3/519Western Ghatsmacrolichensautophagyapoptosiscytotoxicityusnic acid (UA) |
| spellingShingle | Madhuree Kumari Siya Kamat Sandeep Kumar Singh Ajay Kumar C. Jayabaskaran Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens Plants Western Ghats macrolichens autophagy apoptosis cytotoxicity usnic acid (UA) |
| title | Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens |
| title_full | Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens |
| title_fullStr | Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens |
| title_full_unstemmed | Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens |
| title_short | Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens |
| title_sort | inhibition of autophagy increases cell death in hela cells through usnic acid isolated from lichens |
| topic | Western Ghats macrolichens autophagy apoptosis cytotoxicity usnic acid (UA) |
| url | https://www.mdpi.com/2223-7747/12/3/519 |
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