scholarly journals Prolactin regulates ZNT2 expression through the JAK2/STAT5 signaling pathway in mammary cells

2009 ◽  
Vol 297 (2) ◽  
pp. C369-C377 ◽  
Author(s):  
Linxi Qian ◽  
Veronica Lopez ◽  
Young Ah Seo ◽  
Shannon L. Kelleher

The zinc transporter ZnT2 ( SLC30A2) plays an important role in zinc secretion into milk during lactation. The physiological process of mammary gland secretion is regulated through complex integration of multiple lactogenic hormones. Prolactin plays a primary role in this regulation through the activation of various signaling cascades including Jak2/STAT5, mitogen-activated protein kinase (MAPK), p38, and phosphatidylinositol 3-kinase (PI3K). The precise mechanisms that regulate the transfer of specific nutrients such as zinc into milk are not well understood. Herein we report that prolactin increased ZnT2 abundance transcriptionally in cultured mammary epithelial (HC11) cells. To delineate the responsible mechanisms, we first determined that prolactin-mediated ZnT2 induction was inhibited by pretreatment with the Jak2 inhibitor AG490 but not by the MAPK inhibitor PD-98059. Using a luciferase reporter assay, we demonstrated that ZnT2 promoter activity was increased by prolactin treatment, which was subsequently abolished by expression of a dominant-negative STAT5 construct, implicating the Jak2/STAT5 signaling pathway in the transcriptional regulation of ZnT2. Two putative consensus STAT5 binding sequences in the ZnT2 promoter were identified (GAS1:−674 to −665 and GAS2:−377 to −368). Mutagenesis of the proximal GAS2 element resulted in complete abrogation of PRL-induced ZnT2 promoter activity. The promoter incorporating the distal GAS1 mutation was only able to respond to very high PRL concentrations. Results from both the mutagenesis and gel shift assays indicated that a cooperative relationship exists between GAS1 and GAS2 for PRL-induced activation; however, the proximal GAS2 plays a more critical role in STAT5-mediated signal transduction compared with the GAS1 element. Finally, chromosome immunoprecipition assay further confirmed that prolactin activates STAT5 binding to the ZnT2 promoter in vivo. Taken together, these results illustrate that prolactin regulates the transcription of ZnT2 through activation of the Jak2/STAT5 signaling pathway to assist in providing optimal zinc for secretion into milk during lactation.

2007 ◽  
Vol 176 (5) ◽  
pp. 709-718 ◽  
Author(s):  
Chunxi Ge ◽  
Guozhi Xiao ◽  
Di Jiang ◽  
Renny T. Franceschi

The extracellular signal–regulated kinase (ERK)–mitogen-activated protein kinase (MAPK) pathway provides a major link between the cell surface and nucleus to control proliferation and differentiation. However, its in vivo role in skeletal development is unknown. A transgenic approach was used to establish a role for this pathway in bone. MAPK stimulation achieved by selective expression of constitutively active MAPK/ERK1 (MEK-SP) in osteoblasts accelerated in vitro differentiation of calvarial cells, as well as in vivo bone development, whereas dominant-negative MEK1 was inhibitory. The involvement of the RUNX2 transcription factor in this response was established in two ways: (a) RUNX2 phosphorylation and transcriptional activity were elevated in calvarial osteoblasts from TgMek-sp mice and reduced in cells from TgMek-dn mice, and (b) crossing TgMek-sp mice with Runx2+/− animals partially rescued the hypomorphic clavicles and undemineralized calvaria associated with Runx2 haploinsufficiency, whereas TgMek-dn; Runx2+/− mice had a more severe skeletal phenotype. This work establishes an important in vivo function for the ERK–MAPK pathway in bone that involves stimulation of RUNX2 phosphorylation and transcriptional activity.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Feng He ◽  
Hang Xiao ◽  
Yixin Cai ◽  
Ni Zhang

Abstract Background Esophageal cancer (ESCA) is one of the most common cancers worldwide and has a very poor prognosis. Hypoxia-inducible factor 1 (HIF1) signaling pathway plays a critical role in tumorigenesis and is therefore considered a potential therapeutic target in the treatment of many cancers. Activating transcription factor 5 (ATF5) facilitates the expression of various genes and has been extensively studied for its potential role in cancer treatment. Methods The expression level of ATF5 in clinic sample was detected by quantitative real time PCR and immunohistochemistry. ATF5 biological function was investigated by western blot, cell cycle analysis, cell viability assay, luciferase reporter assays, colony formation assay, transwell assay, wound healing assay, tube formation assay, and ELISA assay. CHIP and Re-CHIP assay, GST-pulldown, and RNA-sequencing were used to study the cross-talks between ATF5 and HIF1 complex. Mouse xenograft study was utilized to study the correlation of ATF5 and tumor growth in vivo. Student’s t-test or Chi-square test was used for statistical analysis. Results Here, we first found ATF5 was dramatically upregulated in ESCA cancer and related with poor survival time. Next, we found that the expression level of ATF5 had a positive relationship with the proliferation, migration, and invasion ability of ESCA cells. Besides, we innovatively found that ATF5 functions as a novel coactivator in HIF1 transcription complex by binding to HIF1α. Further, we demonstrated that silencing ATF5 phenocopies HIF1α knockdown in tumorigenic properties in vitro and inhibited ESCA tumor angiogenesis and proliferation in vivo. Conclusion Herein, we found ATF5 as a novel component of the HIF1 transcription complex. The findings of the present study may provide new insights into the development of a novel and more efficient therapeutic strategy against ESCA.


2021 ◽  
Author(s):  
Xiaowei Fei ◽  
Ya-nan Dou ◽  
Kai Sun ◽  
Jialiang Wei ◽  
Qingdong Guo ◽  
...  

Abstract Background Tripartite motif (TRIM) 22 and mitogen-activated protein kinase (MAPK) signaling pathways play a critical role in tumor growth and therapeutic resistance of glioblastoma (GBM) respectively. However, the molecular mechanism between TRIM22 and MAPK signaling remains to be clarified. Methods We constructed TRIM22 knockout cell lines for molecular biology experiments, detected potential DNA fragments binding to TRIM22 by ChIP-Seq technology, and verified the sequencing results by ChIP-qPCR and CUT&Tag technology. In addition, we constructed different TRIM22 mutants to detect the binding of proteins in MAPK signaling pathway. Finally, the therapeutic effect was verified in NOD/SCID mice. The difference between the two groups of data conforming to the normal distribution was tested by Student t-test. Results Here, we found for the first time that TRIM22 acts as a transcription factor in the nucleus and binds to exon 2 of the transcript (NM_001204160) of SPHK2 gene to regulate its expression by ChIP-Seq technology, thus indirectly affecting the downstream MAPK signaling pathway. Knockout of TRIM22 using Cas9-sgRNAs resulted in decreased mRNA level of SPHK2 in GBM cells, while overexpression of TRIM22 enhanced it. The ERK1/2 driven luciferase reporter construct identified TRIM22 as a potential activator of MAPK signaling. Knockout and overexpression of TRIM22 regulate the inhibition and activation of MAPK signaling through its RING-finger domain. Co-immunoprecipitation demonstrated that TRIM22 bound to the negative regulator Raf-1 of MAPK signaling and accelerated its degradation by inducing K48-linked ubiquitination. The combination of the two is related to the CC domain and SPRY domain of TRIM22 and the C1D domain of Raf-1. TRIM22 also forms a complex with the downstream regulator ERK1/2 of MAPK and promotes K63-linked ubiquitination, resulting in the phosphorylation of ERK1/2. In addition, in vitro and in situ xenotransplantation models, SPHK2 inhibitor (K145), ERK1/2 inhibitor (Selumetinib) and non-phosphorylated mutant Raf-1S338A inhibited the growth promoting properties of TRIM22 in GBM cell line. Conclusions In conclusion, our study shows that TRIM22 regulates SPHK2 transcription as a transcription factor, indirectly affects MAPK signaling, and activates MAPK signaling through post-translational modification of two critical regulators of MAPK signaling in GBM cells.


2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Jiewei Lin ◽  
Zhiwei Xu ◽  
Junjie Xie ◽  
Xiaxing Deng ◽  
Lingxi Jiang ◽  
...  

AbstractAPOL1 encodes a secreted high-density lipoprotein, which has been considered as an aberrantly expressed gene in multiple cancers. Nevertheless, the role of APOL1 in the regulatory mechanisms of pancreatic cancer remains unknown and should be explored. We identified APOL1 was abnormally elevated in human pancreatic cancer tissues compared with that in adjacent tissues and was associated with poor prognosis. The effects of APOL1 in PC cell proliferation, cell cycle, and apoptosis was verified via functional in vitro and in vivo experiments. The results showed that knockdown of APOL1 significantly inhibited the proliferation and promoted apoptosis of pancreatic cancer. In addition, we identified APOL1 could be a regulator of NOTCH1 signaling pathway using bioinformatics tools, qRT-PCR, dual-luciferase reporter assay, and western blotting. In summary, APOL1 could function as an oncogene to promote proliferation and inhibit apoptosis through activating NOTCH1 signaling pathway expression in pancreatic cancer; therefore, it may act as a novel therapeutic target for pancreatic cancer.


2020 ◽  
Vol 15 (1) ◽  
pp. 284-295
Author(s):  
Yongtian Zhang ◽  
Dandan Zhao ◽  
Shumei Li ◽  
Meng Xiao ◽  
Hongjing Zhou ◽  
...  

AbstractMultiple myeloma (MM) is a serious health issue in hematological malignancies. Long non-coding RNA taurine-upregulated gene 1 (TUG1) has been reported to be highly expressed in the plasma of MM patients. However, the functions of TUG1 in MM tumorigenesis along with related molecular basis are still undefined. In this study, increased TUG1 and decreased microRNA-34a-5p (miR-34a-5p) levels in MM tissues and cells were measured by the real-time quantitative polymerase reaction assay. The expression of relative proteins was determined by the Western blot assay. TUG1 knockdown suppressed cell viability, induced cell cycle arrest and cell apoptosis in MM cells, as shown by Cell Counting Kit-8 and flow cytometry assays. Bioinformatics analysis, luciferase reporter assay, and RNA pull-down assay indicated that miR-34a-5p was a target of TUG1 and directly bound to notch receptor 1 (NOTCH1), and TUG1 regulated the NOTCH1 expression by targeting miR-34a-5p. The functions of miR-34a-5p were abrogated by TUG1 upregulation. Moreover, TUG1 loss impeded MM xenograft tumor growth in vivo by upregulating miR-34a-5p and downregulating NOTCH1. Furthermore, TUG1 depletion inhibited the expression of Hes-1, Survivin, and Bcl-2 protein in MM cells and xenograft tumors. TUG1 knockdown inhibited MM tumorigenesis by regulating the miR-34a-5p/NOTCH1 signaling pathway in vitro and in vivo, deepening our understanding of the TUG1 function in MM.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jiong Ma ◽  
Chunxia Zhou ◽  
Xuejun Chen

Abstract Background Hedgehog (Hh) signaling pathway, which is essential for cell proliferation and differentiation, is noted to be aberrantly activated in tumor from increasing studies in recent years. MicroRNAs (miRNAs) as an important non-coding RNA in cells have been proven to possess a regulatory role specific to the Hh signaling pathway. Here, in vitro and in vivo cellular/molecular experiments were adopted to clarify the regulatory mechanism linking miR-636 to the Hh signaling pathway in ovarian cancer (OVC). Methods Protein–protein interaction analysis was performed to identify the hub gene in the Hh pathway. TargetScan database was used to predict the potential upstream regulators for Gli2. qRT-PCR was performed to test the expression of miR-636, while Western blot was conducted to detect the expression of proteins related to the Hh pathway and epithelial-mesenchymal transition (EMT). For cell functional experiments, HO-8910PM OVC cell line was used. MTT assay and wound healing assay were used to measure the effect of miR-636 on cell proliferation and migration. Flow cytometry was carried out to examine the effect of miR-636 on cell cycle, and Western blot was used to identify the change in expression of Hh and EMT-related proteins. Dual-luciferase reporter gene assay was implemented to detect the targeting relationship between miR-636 and Gli2. Xenotransplantation models were established for in vivo examination. Results Gli2 was identified as the hub gene of the Hh pathway and it was validated to be regulated by miR-636 based on the data from TargetScan and GEO databases. In vitro experiments discovered that miR-636 was significantly lowly expressed in OVC cell lines, and overexpressing miR-636 significantly inhibited HO-8910PM cell proliferation, migration and induced cell cycle arrest in G0/G1 phase, while the inhibition of miR-636 caused opposite results. Dual-luciferase reporter gene assay revealed that Gli2 was the target gene of miR-636 in OVC. Besides, overexpressed miR-636 decreased protein expression of Gli2, and affected the expression of proteins related to the Hh signaling pathway and EMT. Rescue experiments verified that overexpression of Gli2 reversed the inhibitory effect of miR-636 on HO-8910PM cell proliferation and migration, and attenuated the blocking effect of miR-636 on cell cycle. The xenotransplantation experiment suggested that miR-636 inhibited cell growth of OVC by decreasing Gli2 expression. Besides, overexpressing Gli2 potentiated the EMT process of OVC cells via decreasing E-cadherin protein expression and increasing Vimentin protein expression, and it reversed the inhibitory effect of miR-636 on OVC cell proliferation in vivo. Conclusion miR-636 mediates the activation of the Hh pathway via binding to Gli2, thus inhibiting EMT, suppressing cell proliferation and migration of OVC. Trial registration: The experimental protocol was established, according to the ethical guidelines of the Helsinki Declaration and was approved by the Human Ethics Committee of The Second Affiliated hospital of Zhejiang University School of Medicine (IR2019001235). Written informed consent was obtained from individual or guardian participants.


2003 ◽  
Vol 17 (10) ◽  
pp. 1921-1930 ◽  
Author(s):  
Twila A. Jackson ◽  
David M. Koterwas ◽  
Melissa A. Morgan ◽  
Andrew P. Bradford

Abstract Fibroblast growth factors (FGFs) play a critical role in pituitary development and in pituitary tumor formation and progression. We have previously characterized FGF signal transduction and regulation of the tissue-specific rat prolactin (rPRL) promoter in GH4 pituitary cells. FGF induction of rPRL transcription is independent of Ras, but mediated by a protein kinase C-δ (PKCδ)-dependent activation of MAPK (ERK). Here we demonstrate a functional role for the Rho family monomeric G protein, Rac1, in FGF regulation of PRL gene expression via an atypical signaling pathway. Expression of dominant negative Rac, but not RhoA or Cdc42, selectively inhibited FGF-induced rPRL promoter activity. Moreover, expression of dominant negative Rac also attenuated FGF-2 and FGF-4 stimulation of MAPK (ERK). However, in contrast to other Rac-dependent signaling pathways, FGF activation of rPRL promoter activity was independent of the c-Jun N-terminal kinase (JNK) and phosphoinositide 3-kinase/Akt cascades. FGFs failed to activate JNK1 or JNK2, and expression of dominant negative JNK or Akt constructs did not block FGF-induced PRL transcription. Consistent with the role of PKCδ in FGF regulation of PRL gene expression, activation of the rPRL promoter was blocked by an inhibitor of phospholipase Cγ (PLCγ) activity. FGF treatment also induced rapid tyrosine phosphorylation of PLCγ in a Rac-dependent manner. These results suggest that FGF-2 and FGF-4 activate PRL gene expression via a novel Rac1, PLCγ, PKCδ, and ERK cascade, independent of phosphoinositol-3-kinase and JNK.


Endocrinology ◽  
2003 ◽  
Vol 144 (3) ◽  
pp. 839-849 ◽  
Author(s):  
Buffy S. Ellsworth ◽  
Brett R. White ◽  
Ann T. Burns ◽  
Brian D. Cherrington ◽  
Annette M. Otis ◽  
...  

Reproductive function is dependent on the interaction between GnRH and its cognate receptor found on gonadotrope cells of the anterior pituitary gland. GnRH activation of the GnRH receptor (GnRHR) is a potent stimulus for increased expression of multiple genes including the gene encoding the GnRHR itself. Thus, homologous regulation of the GnRHR is an important mechanism underlying gonadotrope sensitivity to GnRH. Previously, we have found that GnRH induction of GnRHR gene expression in αT3-1 cells is partially mediated by protein kinase C activation of a canonical activator protein-1 (AP-1) element. In contrast, protein kinase A and a cAMP response element-like element have been implicated in mediating the GnRH response of the GnRHR gene using a heterologous cell model (GGH3). Herein we find that selective removal of the canonical AP-1 site leads to a loss of GnRH regulation of the GnRHR promoter in transgenic mice. Thus, an intact AP-1 element is necessary for GnRH responsiveness of the GnRHR gene both in vitro and in vivo. Based on in vitro analyses, GnRH appeared to enhance the interaction of JunD, FosB, and c-Fos at the GnRHR AP-1 element. Although enhanced binding of cFos reflected an increase in gene expression, GnRH appeared to regulate both FosB and JunD at a posttranslational level. Neither overexpression of a constitutively active Raf-kinase nor pharmacological blockade of GnRH-induced ERK activation eliminated the GnRH response of the GnRHR promoter. GnRH responsiveness was, however, lost in αT3-1 cells that stably express a dominant-negative c-Jun N-terminal kinase (JNK) kinase, suggesting a critical role for JNK in mediating GnRH regulation of the GnRHR gene. Consistent with this possibility, we find that the ability of forskolin and membrane-permeable forms of cAMP to inhibit the GnRH response of the GnRHR promoter is associated with a loss of both JNK activation and GnRH-mediated recruitment of the primary AP-1-binding components.


2021 ◽  
Author(s):  
Shenshuo Gao ◽  
Zhikai Zhang ◽  
Xubin Wang ◽  
Yan Ma ◽  
Chensheng Li ◽  
...  

Abstract Background: Gastric cancer (GC) is one of the most common malignancies, and more and more evdiences show that the pathogenesis is regulated by various miRNAs.In this study, we investigated the role of miR-875 in GC. Methods:The expression of miR-875-5p was detected in human GC specimens and cell lines by miRNA RT-PCR. The effect of miR-875-5p on GC proliferation was determined by CCK-8 proliferation assay and EDU assay. Migration and invasion were examined by transwell migration and invasion assay and wound healing assay. The interaction between miR-875-5p and its target gene USF2 was verified by a dual luciferase reporter assay. The effects of miR-875-5p in vivo were studied in xenograft nude mice models.Related proteins were detected by Western blot.Results:The results showed that miR-875-5p inhibited the proliferation, migration and invasion of gastric cancer cells in vitro, and inhibited tumorigenesis in vivo. USF2 proved to be a direct target of miR-875-5p. Knockdown of USF2 partially counteracts the effects of miR-875-5p inhibitors.Overexpression of miR-875-5p can inhibit proliferation, migration, and invasion through the TGF-β signaling pathway by down-regulation of USF2 in GC, providing a new research direction for the diagnosis and targeted therapy of GC.Conclusions: MiR-875-5pcan inhibited the progression of GC by directly targeting USF2 and negatively regulating TGF-β signaling pathway.In the future, miR-875-5p is expected to be used as a potential therapeutic target for GC therapy.


2021 ◽  
Author(s):  
Yunxin Zhang ◽  
Kexin Shen ◽  
Hanyi Zha ◽  
Wentao Zhang ◽  
Haishan Zhang

Abstract BackgroundCircular RNA-BTG3 associated nuclear protein (circ-BANP) was identifified to involve in cell proliferation of colorectal cancer (CRC). The aerobic glycolysis is a key metabolism mediating cancer progression. However, the role of circ-BANP on aerobic glycolysis in CRC remains unknown. MethodsThe expression of circ-BANP, microRNA (miR)-874-3p, and mitogen-activated protein kinase 1 (MAPK1) mNRA was detected using quantitative real-time polymerase chain reaction. Cell viability and invasion were measured by cell counting kit-8 assay or transwell assay. Glucose consumption and lactate production were assessed by a glucose and lactate assay kit. XF Extracellular Flux Analyzer was used to determine extracellular acidifification rate (ECAR). Western blot was used to analyze the levels of hexokinase-2 (HK2), pyruvate kinase M2 (PKM2), MAPK1, proliferating cell nuclear antigen (PCNA), Cyclin D1, N-cadherin, E-cadherin, hypoxia inducible factor-1α (HIF-1α), glucose transport protein 1(GLUT1), and c-Myc. The interaction between miR-874-3p and circ-BANP or MAPK1 was confifirmed by dual luciferase reporter assay. In vivo experiments were conducted through the murine xenograft model. ResultsCirc-BANP was up-regulated in CRC tissues and cell lines. Circ-BANP knockdown suppressed CRC cell proliferation, invasion and aerobic glycolysis in vitro as well as inhibited tumor growth in vivo. Circ-BANP was a sponge of miR-874-3p and performed anti-tumor effffects by binding to miR-874-3p in CRC cells. Subsequently, we confifirmed MAPK1 was a target of miR-874-3p and circ-BANP indirectly regulated MAPK1 expression by sponging miR-874-3p. After that, we found MAPK1 overexpression partially reversed circ-BANP deletion-mediated inhibition on cell carcinogenesis and aerobic glycolysis in CRC. ConclusionCirc-BANP accelerated cell carcinogenesis and aerobic glycolysis by regulating MAPK1 through miR- 874-3p in CRC, suggesting a promising therapeutic strategy for CRC treatment.


Sign in / Sign up

Export Citation Format

Share Document