Stigmalactam from Orophea enterocarpa induces human cancer cell apoptosis via a mitochondrial pathway
Ratana Banjerdpongchai1, Benjawan Wudtiwai, Wilart Pompimon
1Dept of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai, ThailandE-mail : rbanjerd@gmail.com.
Abstract:
Stigmalactam, an aristolactam-type alkaloid extracted from Orophea enterocarpa, exerts cytotoxicity against several human and murine cancer cell lines, but the molecular mechanisms remain elusive. The aims of this study were to identify the mode and mechanisms of human cancer cell death induced by stigmalactam employing human hepatocellular carcinoma HepG2 and human invasive breast cancer MDA-MB-231 cells as models, compared to normal murine fibroblasts. It was found that stigmalactam was toxic to HepG2 and MDA-MB-231 cells with IC50 levels of 23.0±2.67 μM and 33.2±4.54 μM, respectively, using MTT assays. At the same time the IC50 level towards murine normal fibroblast NIH3T3 cells was 24.4±6.75 μM. Reactive oxygen species (ROS) production was reduced in stigmalactam-treated cells dose dependently after 4 h of incubation, indicating antioxidant activity, measured by using 2',7',-dichlorohydrofluorescein diacetate and flow cytometry. Caspase-3 and caspase-9 activities were increased in a dose response manner, while stigmalactam decreased the mitochondrial transmembrane potential dose-dependently in HepG2 cells, using 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, indicating mitochondrial pathway-mediated apoptosis. In conclusion, stigmalactam from O. enterocarpa was toxic to both HepG2 and MDA-MB-231 cells and induced human cancer HepG2 cells to undergo apoptosis via the intrinsic (mitochondrial) pathway.
Insights
Stigmalactam, an alkaloid from Orophea enterocarpa, shows cytotoxicity against human cancer cells. It induces apoptosis in hepatocellular carcinoma HepG2 cells via the intrinsic mitochondrial pathway.
Area of Science:
- Natural Products Chemistry
- Molecular Biology
- Cancer Research
Background:
- Aristolactam-type alkaloids, like stigmalactam from Orophea enterocarpa, exhibit cytotoxic properties.
- The precise molecular mechanisms underlying stigmalactam's anti-cancer effects are not fully understood.
- Investigating novel anti-cancer agents is crucial for developing new therapeutic strategies.
Purpose of the Study:
- To elucidate the mode and mechanisms of human cancer cell death induced by stigmalactam.
- To evaluate stigmalactam's cytotoxicity against human hepatocellular carcinoma (HepG2) and invasive breast cancer (MDA-MB-231) cell lines.
- To compare stigmalactam's effects on cancer cells versus normal murine fibroblasts (NIH3T3).
Main Methods:
- Cytotoxicity was assessed using MTT assays to determine half-maximal inhibitory concentrations (IC50).
- Reactive oxygen species (ROS) production was measured using 2',7',-dichlorofluorescein diacetate and flow cytometry.
- Apoptosis was evaluated by measuring caspase-3 and caspase-9 activities and assessing mitochondrial transmembrane potential using 3,3'-dihexyloxacarbocyanine iodide and flow cytometry.
Main Results:
- Stigmalactam demonstrated toxicity towards HepG2 (IC50=23.0±2.67 μM) and MDA-MB-231 (IC50=33.2±4.54 μM) cells, with comparable toxicity to normal NIH3T3 cells (IC50=24.4±6.75 μM).
- Stigmalactam exhibited dose-dependent antioxidant activity by reducing ROS production.
- Increased caspase-3 and caspase-9 activities and decreased mitochondrial transmembrane potential indicated apoptosis induction via the intrinsic pathway in HepG2 cells.
Conclusions:
- Stigmalactam is cytotoxic to human hepatocellular carcinoma (HepG2) and invasive breast cancer (MDA-MB-231) cells.
- Stigmalactam induces apoptosis in HepG2 cells through the intrinsic (mitochondrial) pathway.
- The findings provide insights into the molecular mechanisms of stigmalactam's anti-cancer activity.
Related Concept Videos
01:31The Intrinsic Apoptotic Pathway
01:30Apoptosis
01:17The Extrinsic Apoptotic Pathway
01:30Overview of Cell Death
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the...
01:22Cellular Injury V: Apoptosis and Autophagy