Long non-coding RNA H19 regulates proliferation of ovarian granulosa cells via STAT3 in polycystic ovarian syndrome
Authors: Jiangrong Hei
Yongbian Ren
Jianxun Wei
Hongmei Li
Li Li
Journal: Archives of Medical Science (2021)
Discipline: CLINICAL MEDICINE
Keywords: STAT3; apoptosis; lncRNA H19; polycystic ovarian syndrome.

Abstract:  Introduction: Studies have shown that long non-coding RNAs (lncRNA) are aberrantly expressed in polycystic ovarian syndrome (PCOS) ovaries and may have a role in PCOS development. In this study, the role and therapeutic implications of lncRNA H19 were investigated in PCOS ovaries and granulosa cells. Material and methods: qRT-PCR was used for expression analysis. Cell Counting Kit 8 (CCK-8) assay was used for cell viability and acridine orange/ethidium bromide (AO/EB) and Annexin V/propidium iodide staining was used to detect apoptosis. All transfections were carried out with Lipofectamine 2000 reagent. Western blot analysis was used for protein expression analysis. Results: The expression of lncRNA H19 was remarkably upregulated in the PCOS ovarian tissues as well as the granulosa cells. Suppression of lncRNA H19 expression caused the inhibition of KGN granulosa cell proliferation due to the triggering of apoptosis. Bioinformatic analysis revealed the presence of the GAS binding site for STAT3 in the promoter of lncRNA H19. Silencing of STAT3 suppressed the expression of lncRNA H19 in KGN cells and also halted their growth by triggering apoptosis. Co-transfect experiments revealed that STAT3 and lncRNA H19 silencing cause inhibition of KGN growth synergistically. Conclusions: lncRNA H19 regulates the growth of ovarian granulosa cells and might prove to be a therapeutic target for management of PCOS. 

Retracted: No

PubPeer comments:
 I became interested in the far-reaching influence of a 2018 in-vitro paper about Daidzein, [Hua et al (2018)] . Google Scholar informs us that it 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). Please excuse the length and list-based nature of this comment. Feel free to skip to the end. There will not be a test. - [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. ----------------------------------------------------------- The point of all this is that the present paper appears to have been constructed with the same template, as it includes the same stereotyped Apoptosis Assay paragraph with the same choice of Hua et al as a precedent. I hope the authors will forgive me for speculating that it is perhaps the work of the same third-party company.  Around 5u201310 u03bcl of culture was taken on the cover slips and stained with AO EB solution and observed under a microscope for determination of the percentage of apoptosis. The transfected KGN cells were stained with annexin V PI and subsequently examined by a flow cytometer as described previously [23]. The reference is to  23. 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: 3485-92. , 
 *[right]* Figure 2B and 4C.  Silencing of long non-coding (lncRNA) H19 in KGN cells triggers apoptosis as depicted by... (B) Annexin V propidium iodide (PI) staining of normal or Si-H19 transfected KGN cells. ;  Annexin V propidium iodide (PI) staining (C) of the NC and Si-STAT3 transfected KGN cells. *[left]* Figure 4 from [Yang et al (2019)] .  Estimation of apoptotic cell populations of OVCAR-3 cells determined by annexin V PI staining. The Figure shows that isoacteoside increases the percentage of OVCAR-3 apoptotic cells in a concentration-dependent manner. ![file] It may be that the duplicated panels of 2B from Li et al (2019) are a publishing error, since the PDF contains an embedded image that may be the original version: ![file] ,