Podophyllotoxin Isolated from Podophyllum peltatum Induces G2/M Phase Arrest and Mitochondrial-Mediated Apoptosis in Esophageal Squamous Cell Carcinoma Cells

Abstract

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in East Asia and is the seventh leading cause of cancer deaths. Podophyllotoxin (PT), a cyclolignan isolated from podophyllum peltatum, exhibits anti-cancer effects at the cellular level. This study investigated the underlying mechanism of anti-cancer effects induced by PT in ESCC cells. Exposure to increasing concentrations of PT led to a significant decrease in the growth and anchorage-independent colony numbers of ESCC cells. PT showed high anticancer efficacy against a panel of four types of ESCC cells, including KYSE 30, KYSE 70, KYSE 410, KYSE 450, and KYSE 510 by IC50 at values ranges from 0.17 to 0.3 μM. We also found that PT treatment induced G2/M phase arrest in the cell cycle and accumulation of the sub-G1 population, as well as apoptosis. Exposure to PT triggered a significant synthesis of reactive oxygen species (ROS), a loss of mitochondrial membrane potential (MMP), and activation of various caspases. Furthermore, PT increased the levels of phosphorylated c-Jun N-terminal kinase (JNK), p38, and the expression of Endoplasmic reticulum (ER) stress marker proteins via ROS generation. An increase in the level of pro-apoptotic proteins and a reduction in the anti-apoptotic protein level induced ESCC cell death via the loss of MMP. Additionally, the release of cytochrome c into the cytosol with Apaf-1 induced the activation of multi-caspases. In conclusion, our results revealed that PT resulted in apoptosis of ESCC cells by modulating ROS-mediated mitochondrial and ER stress-dependent mechanisms. Therefore, PT is a promising therapeutic candidate as an anti-cancer drug against ESCC for clinical use.

Chemistry and Biology of Podophyllotoxins: An Update

“…[72] Additionally, Yoon et al discovered that PPT induced a significant increase in ROS producing oxidative stress, loss of mitochondrial membrane potential and expression of endoplasmic reticulum stress marker proteins, ultimately leading to cellular damage. [73] Untargeted delivery and uncontrolled release of many prodrugs can compromise the therapeutic efficacy of the drug. Through drug delivery systems and tumor-targeted modifications, nanoparticle systems provide ideas for clinical applications in oncology therapy.…”

Forest, Foods, and Nutrition

“…The discussion of the role of forest foods rich in compounds with nutrients and biologically active compounds to complement people's diet and the contribution of forest foods to a healthy diet has been exploited, adding information to the area of interest. The beneficial potential of medicinal plants and herbs has been investigated in different papers [9][10][11][12]. Functionally, extracts and biologically active components [13][14][15][16][17][18] from forest products are experiencing great interest for both research and potential application in nutraceutical, pharmaceutical, and cosmetic fields [19,20].…”