Antitumor and apoptotic effects of 5-methoxypsoralen in U87MG human glioma cells and its effect on cell cycle, autophagy and PI3K/Akt signaling pathway
Authors: Haixia Guo
Yuelin He
Chaoke Bu
Zhiyong Peng
Journal: Archives of Medical Science (2019)
Discipline: CLINICAL MEDICINE
Keywords: 5-methoxypsoralen; apoptosis; coumarins; flow cytometry; glioma.
Affiliations: Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.

Abstract:  Introduction: The main purpose of the current study was to investigate the antitumor effects of 5-methoxypsoralen in U87MG human glioma cells along with studying its effects on cell cycle progression, autophagy and the PI3K/Akt signaling pathway. Material and methods: The cytotoxic effects of the drug were demonstrated by the MTS cell viability assay while its effects on cellular morphology associated with cell apoptosis were evaluated by phase contrast and fluorescence microscopic techniques. Effects of 5-methoxypsoralen on the cell cycle were studied by flow cytometry while effects on PI3K/Akt proteins were evaluated by western blot assay. Results: The results indicate that 5-methoxypsoralen led to time-dependent as well as dose-dependent inhibitory effects on U-87MG human glioma cells. 5-Methoxypsoralen led to a substantial decrease of cell count along with distorted cell morphology. The molecule also led to DNA ladder formation which increased with increasing doses of 5-methoxypsoralen. 5-methoxypsoralen also led to dose-dependent G2/M phase cell cycle arrest. 5-Methoxypsoralen-treated cells also exhibited altered cell ultrastructure with the appearance of autophagic vacuoles and the number of these vacuoles increased with increasing drug dose. Conclusions: In brief, the results indicate that 5-methoxypsoralen exerted potent anticancer and apoptotic effects in U-87MG human glioma cells along with inducing cell cycle arrest, autophagy and m-TOR/PI3K/Akt signaling pathway inhibition. 

Retracted: No

PubPeer comments:
 *[left]* Figure 3 from [Guo et al (2019)] .  5-Methoxypsoralen induces significant morphological changes in U87MG human glioblastoma cells. The cells were treated with different concentrations u2013 0 (A), 5 (B), 20 (C) and 50 (D) u03bcM u2013 for 48 h and then observed under an inverted phase contrast microscope at 200. magnification. Orange colored arrows represent apoptotic cells . *[right]* Figure 4 from [Gong et al (2017)] . H t to Elisabeth Bik for the annotated version, emphasising that (C) and (D) are the same apart from a 180-deg flip. ![file] , 
 *[left]* Figure 4 from [Guo et al (2019)] .  Fluorescence microscopic study of the apoptosis induced by 5-methoxypsoralen in U87MG human glioblastoma cells. The cells were treated with 0 (A), 5 (B), 20 (C), and 50 u03bcM (D) doses of 5-methoxypsoralen for 48 h and then stained with acridine orange propidium iodide double dye and finally examined with a fluorescence microscope at 400. magnification. Green arrows indicate viable cells, while yellow arrows indicate apoptotic cells . *[right]* Figure 3 from [Gong et al (2017)] . H t to Elisabeth Bik for the annotated version. ![file] , 
 Figure 6.  5-Methoxypsoralen induces G2 M cell cycle in U87MG human glioblastoma cells. The cells were treated with varying doses (0, 5, 20 and 50 u03bcM) of 5-methoxypsoralen for 48 h, stained with propidium iodide dye and then analyzed by flow cytometry . ![file] , 
 *[left]* Figure 7 from [Guo et al (2019)] .  5-Methoxypsoralen induces autophagic cell death in U87MG human glioblastoma cells. The cells were treated with 0, 5, 20 and 50 u03bcM doses of 5-methoxypsoralen for 48 h and then analyzed using a transmission electron microscope at 8000. resolution. Arrows indicate autophagic vacuoles . *[right]* Figure 5 from [Gong et al (2017)] . H t to Elisabeth Bik for the annotated version. The frames are not identical, with many vacuoles that are void in the left version becoming black in the right version, but the annotations still apply. ![] , 
 *[left]* Figure 5 from [Guo et al (2019)] .  5-Methoxypsoralen led to DNA fragmentation in U87MG human glioblastoma cells. The cells were treated with 0 (control), 5, 20 and 50 u00b5M doses of the drug, incubated for 48 h and then harvested. The DNA was extracted and then analyzed using 1.5% agarose gel electrophoresis . *[right]* Figure 7 from [Chen et al (2019)] .  Methylwogonin induced DNA fragmentation in A375 human malignant melanoma cells. The cells were treated with 0 (control), 50, 150 and 300 u00b5M doses of the drug, incubated for 48 h and then harvested. The DNA was extracted and then analysed using 1.5% agarose gel electrophoresis . ![file] , 
  Figure 8. 5-Methoxypsoralen led to dose-dependent inhibition of m-TOR PI3K Akt signaling pathway proteins. The effect of the drug on expression of these proteins was evaluated by western blot assay . Unexpected similarity. ![file] ,