Cytoskeleton Regulator PAK4 Plays a Role in Growth and Survival of Myeloma with a Potential Therapeutic Intervention Using PAK4 Allosteric Modulators (PAMs)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3381-3381
Author(s):  
Mariateresa Fulciniti ◽  
Rajya Lakshmi Bandi ◽  
Nicola Amodio ◽  
Antonia Cagnetta ◽  
William Senapedis ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Cellular Migration ◽  
Allosteric Modulators ◽  
Loss Of Function ◽  
Growth And Survival ◽  
Function Study ◽  
Orally Bioavailable ◽  
Cell Growth And Survival

Abstract P21-activated serine/threonine kinase 4 (PAK4) is a major effector of Cdc42 and is essential for cytoskeleton reorganization. PAK4 is activated in cancer cells, promotes cell migration and anchorage-independent cell growth, and protects against apoptosis induction. With cellular migration playing a significant role in multiple myeloma (MM) cell growth and survival, we investigated the expression and subcellular localization of PAK4 in MM cells. We observed a high level of un-phosphorylated PAK4 in the cytoplasm and high levels of phosphorylated PAK4 in the nucleus. In a gain-of-function study, over-expression of PAK4-eGFP in PAK4-deficient MM cells (RPMI8226) significantly increased cell proliferation and survival. Conversely, in a loss-of-function study, conditional knock-down of PAK4 expression with TRIPZ-lentiviral vectors decreased MM cell proliferation and survival proportionally to the reduction in PAK4. With a significant impact of PAK4 on MM cell growth, we identified a class of orally bioavailable PAK4 allosteric modulators (PAMs; e.g. KPT-6604, -7189, -7657, -8752). We observed inhibition of MM cell growth and survival after treatment with PAMs even in the presence of bone marrow microenvironment. In addition, there is a significant correlation between PAK4 expression and the inhibition concentration (IC50s) of PAMs in proliferation assays. Moreover, inhibition of PAK4 induced receptor and mitochondrial-mediated apoptotic pathways via Caspase-3, -8, and -9 activation. PAMs had no significant effect on normal PBMCs, suggesting a favorable therapeutic index in MM treatment. Finally, in two murine models of human myeloma, orally bioavailable KPT-8752 given daily was able to inhibit tumor growth in vivo and prolong overall survival. In summary, PAK4 plays an important cellular and molecular function in myeloma and its inhibition with a new class of PAK4 allosteric modulators provides a novel therapeutic approach for the treatment of MM. Disclosures Senapedis: Karyopharm: Employment. Baloglu:Karyopharm: Employment. Anderson:Celgene: Consultancy; Sanofi-Aventis: Consultancy; Onyx: Consultancy; Acetylon: Scientific Founder, Scientific Founder Other; Oncoprep: Scientific Founder Other; Gilead Sciences: Consultancy.

Role of small GTP binding proteins in the growth-promoting and antiapoptotic actions of gastrin

2004 ◽  
Vol 287 (3) ◽  
pp. G715-G725 ◽  
Author(s):  
Vinzenz Stepan ◽  
Saravanan Ramamoorthy ◽  
Nonthalee Pausawasdi ◽  
Craig D. Logsdon ◽  
Frederick K. Askari ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Binding Proteins ◽  
Dominant Negative ◽  
Growth And Survival ◽  
Gtp Binding Proteins ◽  
Gtp Binding ◽  
Growth Promoting ◽  
Stimulation Of ◽  
Cell Growth And Survival

G17 has growth promoting and antiapoptotic effects on the AR4–2J pancreatic acinar cell line. We previously reported that whereas MAPK regulates G17-stimulation of AR4–2J cell proliferation, Akt mediates the antiapoptotic action of G17. We examined the signal-transduction pathways mediating G17 stimulation of AR4–2J cell growth and survival. G17 activated the small GTP binding proteins Ras, Rac, Rho, and Cdc42. Transduction of the cells with adenoviral vectors expressing dominant negative Akt, Ras, Rho, and Cdc42 but not dominant negative Rac inhibited AR4–2J cell proliferation and survival. Both exoenzyme C3 from Clostridium botulinum (C3), a toxin known to inactivate Rho, and PD98059, a MAPK inhibitor, reversed G17 inhibition of AR4–2J cell apoptosis. G17 induction of Akt activation was reduced by >60% by both dominant negative Ras and Rho and by 30% by dominant negative Cdc42. In contrast, G17-stimulated MAPK activation was blocked by >80% by dominant negative Ras but not by dominant negative Rho and Cdc42. Similar results were observed in the presence of C3. Dominant negative Rac failed to affect G17 induction of both Akt and MAPK, whereas it inhibited sorbitol by almost 50% but not G17-stimulated activation of p38 kinase. Thus G17 promotes AR4–2J cell growth and survival through the activation of multiple GTP binding proteins, which, in turn, regulate different protein kinase cascades. Whereas Ras activates Akt and MAPK, Rho and Cdc42 appear to regulate Akt and possibly other as yet unidentified kinases mediating the growth-stimulatory actions of G17.

scholarly journals Ferroportin Downregulation Promotes Cell Proliferation By Modulating the Nrf2-Mir 17-5p Axis in Multiple Myeloma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5596-5596
Author(s):  
Jumei Shi ◽  
Yuanyuan Kong ◽  
Liangning Hu ◽  
Gege Chen ◽  
Dandan Yu ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cell Growth ◽  
Conflicts Of Interest ◽  
Biological Effects ◽  
Regulatory Protein ◽  
Osteoclast Differentiation ◽  
Iron Concentration ◽  
Growth And Survival ◽  
Cell Growth And Survival

Recent findings demonstrate that aberrant downregulation of the iron-exporter protein, ferroportin (FPN1), is associated with poor prognosis and osteoclast differentiation in multiple myeloma (MM). Here, we show that FPN1 was downregulated in MM and that clustered regularly interspaced short palindromic repeat (CRISPR)-mediated FPN1 knockout promoted MM cell growth and survival. Using an microRNA target-scan algorithm, we identified miR 17-5p as an FPN1 regulator that promoted cell proliferation and cell cycle progression, and inhibited apoptosis - both in vitro and in vivo. miR 17-5p inhibited retarded tumor growth in a MM xenograft model. Moreover, restoring FPN1 expression at least partially abrogated the biological effects of miR 17-5p in MM cells. The cellular iron concentration regulated the expression of the iron-regulatory protein (IRP) via the 5-untranslated region of IRP messenger RNA and modulated the post-transcriptional stability of FPN1. Bioinformatics analysis with subsequent chromatin immunoprecipitation-polymerase chain reaction and luciferase activity experiments revealed that the transcription factor Nrf2 drove FPN1 transcription through promoter binding and suppressed miR 17-5p (which also increased FPN1 expression). Nrf2-mediated FPN1 downregulation promoted intracellular iron accumulation and reactive oxygen species. Our study links FPN1 transcriptional and post-transcriptional regulation with MM cell growth and survival, and validates the prognostic value of FPN1 and its utility as a novel therapeutic target in MM. Figure 1 Disclosures No relevant conflicts of interest to declare.

Functional and Clinical Impact of Splicing Factor Dysregulation in Multiple Myeloma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 726-726 ◽  
Author(s):  
Mariateresa Fulciniti ◽  
Mehmet Kemal Samur ◽  
Naim Ur Rashid ◽  
Rajya Lakshmi Bandi ◽  
Manoj Bhasin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Board Of Directors ◽  
Plasma Cells ◽  
Splicing Factor ◽  
Alternate Splicing ◽  
Advisory Committees ◽  
Growth And Survival ◽  
Cell Growth And Survival

Abstract Transcriptome modifiers such as alternative pre-mRNA splicing (AS), long non-coding RNA and microRNA (miRNA) need to be considered in order to provide a more accurate genomic framework for clinical correlation, as well as for high value therapeutic target discovery. Aberrant splicing of numerous genes has been reported in other malignancies, including a small number of genes reported in MM. We have evaluated AS in MM by analyzing clinically annotated high throughput RNA-seq data from 410 newly-diagnosed patients and 18 normal donor plasma cells. We observed a profound and significant AS in MM with over 600 genes showing significant changes in relative isoform abundances (isoform switching) between MM and normal samples. Importantly, unsupervised analysis identified clinically relevant MM subgroups with high and low splicing index respectively and showed significant impact of alternate splicing on overall clinical outcome. Based on these data, we next focused on understanding the molecular mechanisms driving aberrant alternate splicing in myeloma. Several studies provide evidence that an abnormally expressed splicing factor (SF) can have oncogenic properties by impacting alternative splicing of cancer-associated genes. We detected dysregulated expression of several SFs, including SF3B1, Fox2, SRSF1, NONO, in patients with MM compared to normal plasma cells with impact on outcome, highlighting for the first time the prognostic significance of splicing related factors in myeloma. We further observed that overexpression of some of these SFs increased cell proliferation, enhanced anchorage independent growth in semi-solid medium, and affected tumorigenic potential. We have further investigated role of Serine/Arginine Splicing Factor 1 (SRSF1) in MM by gain of- and loss of- function studies. Enforced expression of SRSF1 in MM cells significantly increased proliferation, especially in the presence of bone marrow stromal cells. Conversely, transient or stable downregulation of SRSF1 with specific siRNA and shRNAs respectively, significantly inhibited MM cell proliferation and cell survival. We have also investigated a small molecular inhibitor of SRSF1 (TG003) and observed inhibition of MM cell growth and survival. The impact of this inhibitor on allelic isoforms of specific gene targets is undergoing. To dissect the mechanisms involved in the SRSF1-mediated MM growth induction, we used SRSF1 mutants lacking either of the two RNA-recognition motifs (ΔRRM1 or ΔRRM2 mutants) or the serine/argine-rich C-terminal domain (ΔRS mutant) involved in protein-protein interactions, subcellular localization, and recruitment of spliceosome components. We also used a C-terminal fusion of SRSF1 with the nuclear-retention signal of SRSF2 (NRS1 mutant), to force SRSF1 retention in the nucleus and assess the role of its nuclear versus cytoplasmic functions. We surprisingly found that only NRS1 mutant failed to promote MM growth, suggesting an important role of cytoplasmic SRSF1 in promoting MM cells proliferation. Finally, using genome wide chromatin and transcription landscape mapping techniques, we have found SRSF1 to be under the transcriptional control of E2F1, a transcription factor with significant impact on MM cell growth and survival. A significant reduction in SRSF1 at mRNA and protein levels was observed after E2F1 and/or E2F1 heterodimerization partner Dp1 gene silencing. Moreover, peptide-based strategy to abrogate interaction between Dp1-E2F1 led to decreased SRSF1 expression levels. These results indicate a functional role and clinical significance of a gene involved in regulation of alternate splicing in MM. The study highlights the need to further understand the splicing pattern in myeloma and also supports the emerging concept that splicing programs, together with transcriptional programs participate in the altered cellular function during tumor initiation and progression. Disclosures Munshi: onyx: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees; millenium: Membership on an entity's Board of Directors or advisory committees; novartis: Membership on an entity's Board of Directors or advisory committees.

scholarly journals PYCR1 interference inhibits cell growth and survival via c-Jun N-terminal kinase/insulin receptor substrate 1 (JNK/IRS1) pathway in hepatocellular cancer

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Juhua Zhuang ◽  
Yanan Song ◽  
Ying Ye ◽  
Saifei He ◽  
Xing Ma ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Tumor Growth ◽  
Insulin Receptor ◽  
Cell Apoptosis ◽  
Normal Liver ◽  
Insulin Receptor Substrate ◽  
Growth And Survival ◽  
Qrt Pcr

Abstract Background Liver cancer is the second leading causes of cancer-related death globally. Pyrroline-5-carboxylate reductase 1 (PYCR1) plays a critical role in metabolic profiles of tumors. Therefore, it is necessary to explore the mechanisms of PYCR1 on cell growth and survival in hepatocellular carcinoma (HCC). Methods Protein and mRNA expression levels of PYCR1 in 140 pairs of tumor and adjacent normal liver tissues of HCC patients were analyzed by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR). Expressions of PYCR1 were inhibited in BEL-7404 cells and SMMC-7721 cells using gene interference technology. The cell proliferation was detected by Celigo and MTT assay. The colony formation assay was also performed. The cell apoptosis was measured by flow cytometric assay. The effect of PYCR1 interference on tumor growth was observed by xenograft nude mice assay in vivo. The downstream pathway of PYCR1 interference was searched by microarray and bioinformatics analysis, and validated by qRT-PCR and western blot. Results PYCR1 levels were significantly up-regulated in HCC tumor tissues than adjacent normal liver tissues in both protein and mRNA levels (P < 0.01). In vitro, the cell proliferation was significantly slower in shPYCR1 group than shCtrl group in BEL-7404 and SMMC-7721 cells (P < 0.001). The colony number was significantly smaller after PYCR1 interference (P < 0.01). The percentage of apoptosis cells significantly increased in shPYCR1 group (P < 0.01). In vivo, PYCR1 interference could obviously suppress tumor growth in xenograft nude mice. The volume and weight of tumors were significantly smaller via PYCR1 interference. The c-Jun N-terminal kinase (JNK) signaling pathway significantly altered, and insulin receptor substrate 1 (IRS1) were significantly down-regulated by PYCR1 interference in both mRNA and protein levels (P < 0.001). Conclusion PYCR1 interference could inhibit cell proliferation and promote cell apoptosis in HCC through regluting JNK/IRS1 pathway. Our study will provide a drug target for HCC therapy and a potential biomarker for its diagnosis or prognosis.

Human Monoclonal Antibody Targeting IL-17A (AIN457) Down-Regulates MM Cell-Growth and Survival and Inhibits Osteoclast Development In Vitro and In Vivo: A Potential Novel Therapeutic Application In Myeloma

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 456-456
Author(s):  
Rao H Prabhala ◽  
Mariateresa Fulciniti ◽  
Dheeraj Pelluru ◽  
Puru Nanjappa ◽  
Christine Pai ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Cell Growth ◽  
Stromal Cells ◽  
Human Monoclonal Antibody ◽  
Critical Role ◽  
Osteoclast Differentiation ◽  
Growth And Survival ◽  
Cell Growth And Survival

Abstract Abstract 456 We have previously demonstrated that IL-17 producing TH17cells, a new subset of T helper cells, are significantly elevated in peripheral blood and bone marrow (BM) from patients with multiple myeloma (MM) and IL-17 produced by these cells promotes MM cell growth and survival, suppresses immune responses and induces osteoclast differentiation both in vitro and in vivo. Based on these observations we have investigated the effects of human anti-IL-17A monoclonal antibody (mAb), AIN-457, in MM. We observed that whereas IL-17A induced proliferation of MM cells (+30.7+2.7%) compared to control; anti-IL-17A mAb AIN-457 significantly inhibited MM cell growth both in presence and absence of BM stromal cells, as measured by thymidine incorporation (−18.7+1.5% and −22.7+2.6% respectively). We have further confirmed these inhibitory effects of anti-IL-17A antibody using MM cell colony forming assay with MethoCult agar plates. While presence of IL-17A increased the colony number from 80 in control plates to 188, presence of AIN-457 reduced the colonies to <40 per unit area (p < 0.01). Evaluating the mechanism of action, IL-17A induced IL-6 production (+289.6+38%; p<0.01); while AIN457 significantly down-regulated IL-6 production (−25+7%; p<0.05) in MM-BMSC co-culture. We also observed that AIN-457 significantly reduced adhesion of MM cells to stromal cells (27%, p=0.011). AIN457 significantly inhibited IL-6 production in human fetal bone chips in the presence of MM cells within 24 hours of ex-vivo culture (control − 487+39 pg/ml; IL-17 990+27 pg/ml; p<0.01 and AIN-457 − 326+7 pg/ml; p<0.01). Since IL-17A plays a critical role in bone damage, we further evaluated the effect of this mAb on the generation of osteoclasts. When normal BM cells were cultured for three weeks in osteoclast supporting medium, presence of AIN-457 significantly inhibited TRAP+ multinucleated osteoclast cell numbers by>60%. We next evaluated the efficacy of AIN-457 in vivo in the murine models of human myeloma; in the subcutaneous MM xenograft model, we observed significant reduction in tumor volumes by pre-treatment with AIN457 compared to control (142+77 mm versus 355+56 mm, p=0.019) while IL-17A significantly increased MM cell growth (727+135 mm, p=0.01). More importantly in the SCIDhu model of human myeloma where MM cells grow within the human microenvironment in the mice, administration of AIN-457 weekly for 4 weeks after the first detection of tumor in mice led to a significant inhibition of tumor growth as measured by human sIL-6 receptor compared to control mice (5.9±2.2 ng/ml versus 23.2±6.3 ng/ml; n=7; P <0.01). These pre-clinical in vitro and in vivo observations confirm the role of IL-17A produced by TH17 cells in MM and provide the rationale for clinical evaluation of AIN 457 for both anti-myeloma effects as well as to improve bone disease in myeloma. Disclosures: No relevant conflicts of interest to declare.

scholarly journals XB130/Tks5 scaffold protein interaction regulates Src-mediated cell proliferation and survival

2015 ◽  
Vol 26 (24) ◽  
pp. 4492-4502 ◽  
Author(s):  
Serisha Moodley ◽  
Xiao Hui Bai ◽  
Andras Kapus ◽  
Burton Yang ◽  
Mingyao Liu
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Sh3 Domain ◽  
Scaffold Protein ◽  
Macromolecular Complex ◽  
Down Regulation ◽  
Src Tyrosine Kinase ◽  
Growth And Survival ◽  
Cell Cycle Inhibition ◽  
Cell Growth And Survival

The scaffold protein XB130 regulates cell growth, survival, and migration. Yeast two-hybrid screening suggests that XB130 interacts with another scaffold protein, Tks5. We hypothesized that XB130 and Tks5 form a macromolecular complex to mediate signal transduction cascades for the regulation of cell growth and survival. Coimmunoprecipitation demonstrated that XB130 and Tks5 interact endogenously and form a complex with Src tyrosine kinase. Structure–function studies showed that the fifth SH3 domain of Tks5 binds to the N-terminus of XB130, which contains polyproline-rich motifs. Cell growth and survival studies revealed that down-regulation of XB130 and/or Tks5 reduced cell proliferation, resulting in cell cycle inhibition at the G1 phase and increased caspase 3 activity and apoptosis. Moreover, cell proliferation and survival were increased by overexpression of XB130 or Tks5 but decreased when XB130/Tks5 binding was disrupted by overexpression of XB130 N-terminal deleted mutant and/or Tks5 fifth SH3 domain W1108A mutant. Furthermore, down-regulation of XB130 and/or Tks5 inhibited serum- and growth factor–induced Src activation and downstream phosphorylation of PI3K and Akt. Our results suggest that Tks5, similar to XB130, plays a role in cell proliferation and cell survival and that the interaction between XB130 and Tks5 appears to be critical for regulation of Src-mediated cellular homeostasis.

scholarly journals DEPTOR is a direct p53 target that suppresses cell growth and chemosensitivity

2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Danrui Cui ◽  
Xiaoqing Dai ◽  
Longyuan Gong ◽  
Xiaoyu Chen ◽  
Linchen Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
General Mechanism ◽  
Interacting Protein ◽  
Growth And Survival ◽  
Downstream Target ◽  
Mouse Tissues ◽  
Context Specific

AbstractDEP-domain containing mTOR-interacting protein (DEPTOR), a natural mTOR inhibitor, has essential roles in several processes, including cell growth, metabolism, apoptosis, and immunity. DEPTOR expression has been shown to be diversely controlled at transcriptional levels in cell- and context-specific manners. However, whether there is a general mechanism for the regulation of DEPTOR expression remains largely unknown. Here, we report that DEPTOR is a downstream target of the tumor suppressor, p53, whose activity is positively correlated with DEPTOR expression both in vitro in cell cultures and in vivo in mouse tissues. Mechanistically, p53 directly binds to the DEPTOR promoter and transactivates its expression. Depletion of the p53-binding site on the DEPTOR promoter by CRISPR-Cas9 technology decreases DEPTOR expression and promotes cell proliferation and survival by activating AKT signaling. Importantly, inhibition of AKT by small molecular inhibitors or genetic knockdown abrogates the induction of cell growth and survival induced by deletion of the p53-binding region on the DEPTOR promoter. Furthermore, p53, upon activation by the genotoxic agent doxorubicin, induces DEPTOR expression, leading to cancer cell resistance to doxorubicin. Together, DEPTOR is a direct p53 downstream target and contributes to p53-mediated inhibition of cell proliferation, survival, and chemosensitivity.

Natural Plant Extract Berbamine Is a Potent Inhibitor of Cell Growth and Survival of Human Tenon’s Fibroblasts

2020 ◽  
Vol 63 (6) ◽  
pp. 555-563
Author(s):  
Hui Xu ◽  
Yanan Kong ◽  
Ying Chen ◽  
Na Li ◽  
Shuqiang Zhang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Cell Viability ◽  
Western Blotting ◽  
Mtor Pathway ◽  
Tunel Staining ◽  
Dependent Manner ◽  
Migration Flow ◽  
Growth And Survival ◽  
Cell Growth And Survival

<b><i>Introduction:</i></b> Post-trabeculectomy scarring due to excessive proliferation of human Tenon’s fibroblasts (HTFs) often led to operation failure. Developing a new anti-fibrosis drug with high efficacy to inhibit HTF cell growth will greatly improve the effectiveness of trabeculectomy. <b><i>Objective:</i></b> This study aims to investigate the effect of berbamine (BBM) treatment on the cell growth and survival of HTFs. <b><i>Methods:</i></b> Cultured human fetal Tenon’s fibroblasts (HFTFs) were treated with or without different concentrations of BBM. Cell morphology was observed with a phase contrast microscope. A CCK-8 method and Ki67 immunofluorescence were used to determine cell viability and cell proliferation. A scratch test was used to study cell migration. Flow cytometry and TUNEL staining were performed to detect cell apoptosis. The expression of BAX/BCL-2, ERK, and AKT/mTOR pathway components was determined by Western blotting. <b><i>Results:</i></b> BBM treatment disrupted HFTF normal morphology and inhibited its cell growth in a dose-dependent manner. Ki67 immunofluorescence and scratch assay showed BBM suppressed HFTF cell proliferation and migration. Importantly, BBM dose-dependently increased the BAX/BCL-2 ratio and induced apoptosis in HFTF cells. Western blotting showed BBM significantly inhibited the ERK and AKT/mTOR pathway, and PTEN inhibition ameliorated the inhibitory effect of BBM on cell viability and survival in HFTFs. <b><i>Conclusions:</i></b> BBM potently inhibits the cell growth and survival of HTFs through AKT/mTOR and has the potential to serve as an anti-fibrosis drug after trabeculectomy.

scholarly journals Brain-Derived Neurotrophic Factor Promotes Implantation and Subsequent Placental Development by Stimulating Trophoblast Cell Growth and Survival

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3774-3782 ◽  
Author(s):  
Kazuhiro Kawamura ◽  
Nanami Kawamura ◽  
Wataru Sato ◽  
Jun Fukuda ◽  
Jin Kumagai ◽  
...  
Keyword(s):  
Cell Growth ◽  
Neurotrophic Factor ◽  
Brain Derived Neurotrophic Factor ◽  
Trophoblast Cell ◽  
Phosphatidylinositol 3 Kinase ◽  
Trophoblast Cells ◽  
Placental Development ◽  
Growth And Survival ◽  
Cell Growth And Survival

Successful implantation of the blastocyst and subsequent placental development is essential for reproduction. Expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5, together with their receptor, tyrosine kinase B (TrkB), in trophectoderm cells of blastocyst suggests their potential roles in implantation and placental development. Here we demonstrated that treatment with BDNF promoted blastocyst outgrowth, but not adhesion, in vitro and increased levels of the cell invasion marker matrix metalloproteinase-9 in cultured blastocysts through the phosphatidylinositol 3-kinase pathway. After implantation, BDNF and neurotrophin-4/5 proteins as well as TrkB were expressed in trophoblast cells and placentas during different stages of pregnancy. Both TrkB and its ligands were also expressed in decidual cells. Treatment of cultured trophoblast cells with the TrkB ectodomain, or a Trk receptor inhibitor K252a, suppressed cell growth as reflected by decreased proliferation and increased apoptosis, whereas an inactive plasma membrane nonpermeable K252b was ineffective. Studies using the specific inhibitors also indicated the importance of the phosphatidylinositol 3-kinase/Akt pathway in mediating the action of TrkB ligands. In vivo studies in pregnant mice further demonstrated that treatment with K252a, but not K252b, suppressed placental development accompanied by increases in trophoblast cell apoptosis and decreases in placental labyrinth zone at midgestation. In vivo K252a treatment also decreased fetal weight at late gestational stages. Our findings suggested important autocrine/paracrine roles of the BDNF/TrkB signaling system during implantation, subsequent placental development, and fetal growth by increasing trophoblast cell growth and survival.

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