Murrayanine Induces Cell Cycle Arrest, Oxidative Stress, and Inhibition of Phosphorylated p38 Expression in A549 Lung Adenocarcinoma Cells
Authors: Yi Wang
Jingbao Zhang
Yanfei Gao
Changbo Ma
Journal: Medical Science Monitor (2019)
Discipline: CLINICAL MEDICINE
Keywords: Murrayanine; lung adenocarcinoma cells; apoptosis; cell cycle; protein expression
Affiliations: Department of Oncology, Jiaozhou Peoples' Hospital, Qingdao, Shandong, China (mainland)., Department of Respiratory Medicine, Qingdao Municipal Hospital, Qingdao, Shandong, China (mainland).

Abstract:  BACKGROUND Murrayanine is a carbazole alkaloid derived from Murraya koenigii, which has been used in traditional Chinese medicine in the treatment of cancer. This study aimed to investigate the effects of murrayanine on human lung adenocarcinoma cells in vitro and to investigate the mechanisms of its action. MATERIAL AND METHODS A549 human lung adenocarcinoma cells and MRC-5 human lung fibroblasts were grown in culture, and an MTT assay determined cell viability. Cells were treated for 24 h with increasing doses of murrayanine (0, 9, 18, and 36 µM). Fluorescence, using 4', 6-diamidino-2-phenylindole (DAPI), acridine orange, ethidium bromide, and propidium iodide (PI), were used for the detection of apoptosis. The cell cycle was studied with fluorescence-activated cell sorting (FACS), and Western blot evaluated protein expression. RESULTS Murrayanine treatment resulted in significant dose-dependent inhibition of the growth of A549 cells (p&lt;0.05), with an IC₅₀ of 9 µM, and arrested the cells at the G2/M phase of the cell cycle, reduced the expression of cyclin D and E, CDK2, 4, and 6, and increased the expression of p21 and p27. Murrayanine treatment increased apoptosis of the A549 cells and increased cleaved of caspase-3 and caspase-9, and the Bax/Bcl-2 ratio. Murrayanine treatment increased levels of reactive oxygen species (ROS), disrupted the mitochondrial membrane potential, inhibited invasion, and inhibited phosphorylation of p38 mitogen-activated protein kinase (MAPK) of the A549 cells. CONCLUSIONS Murrayanine induced cell cycle arrest, oxidative stress, and inhibited the expression of phosphorylated p38 in A549 adenocarcinoma cells. 

Retracted: Yes

PubPeer comments:
 *[left]* Figure 8 from [Zhang et al (2019)] .  The concentration-dependent effect of murrayanine treatment on the invasion of the A549 lung adenocarcinoma cells. *[right]* Figure 5B from [Lin et al (2018)] .  Effect of E2F5 overexpression (pcDNA-E2F5) on ... (B) migration and invasion of miR-NC or miR-1179 mimics transfected capan-2 cells. ![] , 
  For determination of the ROS and mitochondrial membrane potential levels, the A549 cells were treated with 0, 9, 18, and 36 u00b5M concentrations of murrayanine for 24 hours and then the ROS and mitochondrial membrane potential levels in the A549 cells were determined, as described previously [11]. The reference is to  11. Hua F, Li CH, Chen XG et al: Daidzein exerts anticancer activity towards SKOV3 human ovarian cancer cells by inducing apoptosis and cell cycle arrest, and inhibiting the Raf MEK ERK cascade. Int J Mol Med, 2018; 41(6): 3485u201392 . Its relevance here is not obvious, as [Hua et al (2018)] did not in fact measure ROS or mitochondrial membrane potential, or even **mention** them. ------------------------------------------------ The influence of [Hua et al (2018)] is surprisingly far-reaching. Google Scholar informs us that their in-vitro study of Daidzein has been cited **71** times. Many of these are review papers, but we also find a surprising number of papers using it in  Apoptosis Assay paragraphs to illustrate the use of flow-cytometry and Annexin V PI staining to quantify cell apoptosis. Indeed, Hua et al did apply the method, but they were not pioneers, nor is their explanation superior to many others. Alternatively, the paper is cited as a precedent for a phytochemical (daidzein) inhibiting cancer proliferation by interrupting the cell cycle. Given all the earlier precedents, the choice again invites some explanation. It is almost as if all these papers were prepared by a third-party service (a papermill ), following a template from one paper to the next, without checking its contents. Consistent with this notion, the papers came to my attention by recycling the same figures (despite a lack of authors in common). - [Jia et al (2019)] .  The slides were covered with a covers lip and examined with a fluorescent microscope. Annexin V PI staining of the OVACAR3 cells was performed as described previously [17]. - [Luo et al (2019)] .  Many plant-derived molecules have been reported to interfere with the **ROS** level in the cancer cells [13]. ... The slides were then covered with a covers lip and examined with a fluorescent microscope. Then 4u2019,6-diamidino-2-phenylindole (DAPI) and annexin V propidium iodide (PI) staining was performed as described previously [13]. - [Zeng et al (2019)] .  The slides were then covered with a covers lip and examined with a fluorescent microscope (BDBiosciences, San Jose, CA, USA). The annexin V PI staining was performed as described previously [8]. - [Wu et al (2019)] *[retracted]*,  The slides were covered with a coverslip and examined with a fluorescent microscope (BD Biosciences, San Jose, CA, USA). Annexin V PI staining was performed as described previously [13]. - [Yang, Chen Wang (2019)] .  The slides were covered with cover slips and examined with a fluorescent microscope. Annexin V PI staining of the SW-948 cells was performed as described previously 16 . - [Yang et al (2019)] .  The slides were covered with cover slips and examined with a fuorescent microscope. DAPI and annexin V propidium iodide (PI) staining were performed as described previously [14] *[14 is a misprint for 13]*. - [Huang et al (2019)] .  The slides were covered with cover slip and examined under fluorescence microscope. Annexin V propidium iodide (PI) staining of the Icariin-treated HeLa cells was performed as described previously [18]. - [Liu et al (2019)] .  The distribution of the breast cancer SK-BR-3 cells in different cycle phases was performed by flow cytometry after PI staining, following the method reported by Hua et al [11]. ...After overnight incubation at 4u00b0C, the cells were subjected to PI staining and flow cytometry. - [Liu et al (2019)] .  After covering the glass slides with cover slips, the cells were analyzed under a fluorescent microscope (Nikon Instruments, Inc., NY, USA). For determining percentage of apoptotic cells, Annexin V PI staining assay using a FACSCalibur flow cytometry (BD Biosciences, NY, USA) was carried out using a previously reported method [12] - [Yin et al (2019)] .  The slides were covered with covers slips and examined with a fluorescent microscope. Annexin V PI staining of the SW-948 cells was performed as previously described [13] . - [Zhang et al (2019)] .  The slides were cover-slipped and examined with a fluorescent microscope. Annexin V PI staining of the SW48 cells was performed as described previously [11] . - [Ma et al (2019)] .  The slides were cover-slipped and examined under a fluorescent microscope. Annexin V PI staining was performed as described previously [15]. - [Li et al (2019)] .  The slides were cover-slipped and assessed by fluorescent microscopy. ROS estimation was performed as described previously [13]. - [Zhang et al (2019)] .  The slides were covered with a cover slip and examined with a fluorescent microscope. Annexin V PI staining was performed as previously described [12]. - [Wu et al (2020)] .  The slides were covered with a covers lip and examined with a fluorescent microscope. Annexin V PI staining of the AGS cells was performed as described previously [15]. - [Yu et al (2020)] .  The slides were cover-slipped and examined with a fluorescent microscope. Annexin V PI staining was performed as described previously [9]. - [Yin et al (2020)] .  The slides were cover-slipped and examined with a fluorescent microscope. Annexin V PI staining was performed as described previously [10]. - [Wei et al (2019)] .  The slides were covered with cover slips and examined with a fluorescent microscope. Annexin V PI staining of the OVACAR-3 cells was performed as described previously [11]. - [Wen et al (2020)] .  The glass slides laden with cell cultures were then covered with cover slips and then using a fluorescence microscope (BioTek Instruments, Inc., Winooski, VT, USA,) the cells were analysed. Quantification of apoptosis was done with annexin V PI staining assay which was performed as reported already (Hua et al., 2018). -------------------------------------------------------------- Cell-cycle arrest: - [Li Han (2019)] .  Cell cycle arrest is another important mechanism by which anticancer molecules exert their effects [16] . - [Mao et al (2019)] .  The arrest of the cancer cells at G2 M phase prevents the cancer cells from entering mitosis and as such the molecules that trigger the cell cycle arrest prevent the proliferation and tumourigenesis of cancer cells (Hua et al., 2018). - [Si et al (2019)] .  Previous studies have shown that depletion of cyclin A and B1 and upregulation of p27 and p21 results in the G2 M arrest of the cells during cell division [21]. - [Zhou et al (2019)] .  The arrest of cancer cells at G2 M phase prevents the cancer cells from entering mitosis, so the molecules that trigger cell cycle arrest prevent the proliferation and tumorigenesis of cancer cells [20]. - [Tan et al (2019)] .  Cell cycle arrest caused by several anticancer agents is an essential mechanism in the growth inhibition of cancer cells [19] . - [Wei et al (2019)] .  Furthermore, arrest of the cells at different phases of the cell cycle is an important route by which anticancer agents halt the growth of cancer cells [18]. - [Zeng et al (2019)] .  Besides autophagy, cell cycle arrest is another mechanism by which anticancer agents exert their anticancer effects [19] . -------------------------------------------------- Another list of papers cite Hua et al (2018) as precedents for methods which those authors did not in fact apply. - [Zhang et al (2019)] .  For determination of the ROS and mitochondrial membrane potential levels, the A549 cells were treated with 0, 9, 18, and 36 u00b5M concentrations of murrayanine for 24 hours and then the ROS and mitochondrial membrane potential levels in the A549 cells were determined, as described previously [11] *(in fact Hua et al did not measure or even mention ROS or mitochondrial membrane potentials)*. - [Guo et al (2019)] .  Plant-derived molecules have been reported to affect ROS levels in the cancer cells [15] . - [Xu et al (2019)] . Hua et al appear in the References but not in the text at all. - [Du et al (2019)] .  **Osteosarcoma** causes significant mortality world over and the treatments available are not efficient and are associated with a number of side-effects [11]. - [Yu et al (2019)] .  Several of the natural products have been reported to induce apoptosis and autophagy through production of ROS [18]. - [Liu et al (2019)] .  The colony formation assay was carried out as described previously [15] *[Hua et al did not perform colony-formation assays]* - [Zhu et al (2020)] .  Estimation of ROS was measured according to a method previously described [8]. - [Du et al (2020)] . Hua et al appear in the References but not in the text at all. , 
 Retracted [25 March 2021] .  An editorial decision has been made to retract this manuscript due to breach of publishing guidelines, following the identification of non-original and manipulated figures. ,