Regulation of mouse primordial follicle formation by signaling through the PI3K pathway

Author(s):  
Joshua J N Burton ◽  
Amanda J Luke ◽  
Melissa E Pepling

Abstract Cell signaling mediated by the KIT receptor is critical for many aspects of oogenesis including the proliferation and migration of primordial germ cells, as well as the survival, growth, and maturation of ovarian follicles. We previously showed that KIT regulates cyst breakdown and primordial follicle formation, and in this study, have investigated the mechanisms downstream of the receptor by modulating the activity of two downstream signaling cascades: the phosphoinositide 3-kinase (PI3K) and the mitogen-activated protein kinase (MAPK) pathways. E17.5 ovaries were cultured for five days with a daily dose of media supplemented with either the PI3K inhibitor LY294002, the MEK inhibitor U0126, or a DMSO vehicle control. Our histological observations aligned with the established role of PI3K in oocyte growth and primordial follicle activation but also revealed that LY294002 treatment delayed the processes of cyst breakdown and primordial follicle formation. U0126 treatment also led to a reduction in oocyte growth and follicle development but did not appear to affect cyst breakdown. The delay in cyst breakdown was mitigated when ovaries were dually dosed with LY294002 and KITL, suggesting that while KIT may signal through PI3K to promote cyst breakdown, other signaling networks downstream of the receptor could compensate. These observations unearth a role for PI3K signaling in the establishment of the ovarian reserve and suggest that PI3K might be the primary mediator of KIT-induced cyst breakdown and primordial follicle formation in the mouse ovary.

2021 ◽  
Author(s):  
Hyun-Jeong Kim ◽  
Jing-fei Dong ◽  
Yejin Song ◽  
Hyo-Il Jung ◽  
Jaewoo Song

Abstract Inflammation is an essential contributing factor in the development of thrombosis. Using a microfluidic flow chamber, we investigated how the proinflammatory cytokine interleukin 6 (IL-6) affects the cleavage of platelet-bearing ultra-large VWF (ULVWF) by plasma ADAMTS13. We found that IL-6-treated platelets perfused at arteriolar shear stress significantly enhanced the ULVWF-platelet complex formation on activated endothelial cells and suppressed their clearance by ADAMTS13 under flow conditions. We also detected the phosphorylation of the serine/threonine kinase Akt and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) in platelets treated with IL-6. Treatment of IL-6-primed platelets with either the phosphoinositol-3 kinase (PI3K) inhibitor LY294002 or the mitogen-activated protein kinase kinase (MEK) inhibitor U0126 reduced the ULVWF-platelet complex formation and restored the clearance of the complex by plasma ADAMTS13, compared to IL-6-primed platelets. Furthermore, IL-6 enhanced the phosphorylation of the intracellular adaptor molecule 14-3-3ζ, which regulates VWF binding to the glycoprotein (GP) Ib-IX complex. The 14-3-3 antagonist R18 significantly increased ADAMTS-13 cleavage of ULVWF strings with adherent IL-6-treated platelets. These findings indicate that IL-6 related intracellular signals of platelet is involved in regulating ULVWF-platelet binding and ULVWF cleavage by ADAMTS13.


Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1082
Author(s):  
Amandeep Singh ◽  
Jeehoon Ham ◽  
Joseph William Po ◽  
Navin Niles ◽  
Tara Roberts ◽  
...  

Thyroid cancer is the most prevalent endocrine malignancy that comprises mostly indolent differentiated cancers (DTCs) and less frequently aggressive poorly differentiated (PDTC) or anaplastic cancers (ATCs) with high mortality. Utilisation of next-generation sequencing (NGS) and advanced sequencing data analysis can aid in understanding the multi-step progression model in the development of thyroid cancers and their metastatic potential at a molecular level, promoting a targeted approach to further research and development of targeted treatment options including immunotherapy, especially for the aggressive variants. Tumour initiation and progression in thyroid cancer occurs through constitutional activation of the mitogen-activated protein kinase (MAPK) pathway through mutations in BRAF, RAS, mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway and/or receptor tyrosine kinase fusions/translocations, and other genetic aberrations acquired in a stepwise manner. This review provides a summary of the recent genetic aberrations implicated in the development and progression of thyroid cancer and implications for immunotherapy.


2012 ◽  
Vol 40 (1) ◽  
pp. 251-256 ◽  
Author(s):  
Pamela A. Lochhead ◽  
Rebecca Gilley ◽  
Simon J. Cook

The MEK5 [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase 5]/ERK5 pathway is the least well studied MAPK signalling module. It has been proposed to play a role in the pathology of cancer. In the present paper, we review the role of the MEK5/ERK5 pathway using the ‘hallmarks of cancer’ as a framework and consider how this pathway is deregulated. As well as playing a key role in endothelial cell survival and tubular morphogenesis during tumour neovascularization, ERK5 is also emerging as a regulator of tumour cell invasion and migration. Several oncogenes can stimulate ERK5 activity, and protein levels are increased by a novel amplification at chromosome locus 17p11 and by down-regulation of the microRNAs miR-143 and miR-145. Together, these finding underscore the case for further investigation into understanding the role of ERK5 in cancer.


Blood ◽  
2000 ◽  
Vol 96 (13) ◽  
pp. 4142-4151 ◽  
Author(s):  
Marcin Majka ◽  
Anna Janowska-Wieczorek ◽  
Janina Ratajczak ◽  
M. Anna Kowalska ◽  
Gaston Vilaire ◽  
...  

Abstract The role of the chemokine binding stromal-derived factor 1 (SDF-1) in normal human megakaryopoiesis at the cellular and molecular levels and its comparison with that of thrombopoietin (TPO) have not been determined. In this study it was found that SDF-1, unlike TPO, does not stimulate αIIbβ3+ cell proliferation or differentiation or have an antiapoptotic effect. However, it does induce chemotaxis, trans-Matrigel migration, and secretion of matrix metalloproteinase 9 (MMP-9) and vascular endothelial growth factor (VEGF) by these cells, and both SDF-1 and TPO increase the adhesion of αIIbβ3+ cells to fibrinogen and vitronectin. Investigating the intracellular signaling pathways induced by SDF-1 and TPO revealed some overlapping patterns of protein phosphorylation/activation (mitogen-activated protein kinase [MAPK] p42/44, MAPK p38, and AKT [protein kinase B]) and some that were distinct for TPO (eg, JAK-STAT) and for SDF-1 (eg, NF-κB). It was also found that though inhibition of phosphatidyl-inositol 3-kinase (PI-3K) by LY294002 in αIIbβ3+ cells induced apoptosis and inhibited chemotaxis adhesion and the secretion of MMP-9 and VEGF, the inhibition of MAPK p42/44 (by the MEK inhibitor U0126) had no effect on the survival, proliferation, and migration of these cells. Hence, it is suggested that the proliferative effect of TPO is more related to activation of the JAK-STAT pathway (unique to TPO), and the PI-3K–AKT axis is differentially involved in TPO- and SDF-1–dependent signaling. Accordingly, PI-3K is involved in TPO-mediated inhibition of apoptosis, TPO- and SDF-1–regulated adhesion to fibrinogen and vitronectin, and SDF-1–mediated migration. This study expands the understanding of the role of SDF-1 and TPO in normal human megakaryopoiesis and indicates the molecular basis of the observed differences in cellular responses.


2008 ◽  
Vol 412 (2) ◽  
pp. e15-e16 ◽  
Author(s):  
Vilmante Borutaite

The question of how Bax is activated during apoptosis to perform its role in permeabilization of mitochondrial membranes is intriguing for investigators in the wide field of cell death research. In their paper published in the Biochemical Journal in 2006, Capano and Crompton presented their discovery that simulated ischaemia causes rapid activation of AMPK (AMP-activated protein kinase) which phosphorylates and activates p38 MAPK (mitogen-activated protein kinase) leading to Bax activation and translocation to mitochondria in isolated cardiac myocytes. This was the first report on the molecular mechanism of Bax activation and migration during ischaemia-induced apoptosis in cardiomyocytes.


Endocrinology ◽  
1997 ◽  
Vol 138 (8) ◽  
pp. 3103-3111 ◽  
Author(s):  
Masahide Ohmichi ◽  
Koji Koike ◽  
Akiko Kimura ◽  
Kanji Masuhara ◽  
Hiromasa Ikegami ◽  
...  

Abstract In this study, prostaglandin (PG) F2α was found to activate mitogen-activated protein (MAP) kinase and MAP kinase kinase (MEK) in cultured rat puerperal uterine myometrial cells. PGF2α stimulation also led to an increase in phosphorylation of raf-1, son of sevenless (SOS), and Shc. Furthermore, we examined the mechanism by which PGF2α induced MAP kinase phosphorylation. Both pertussis toxin (10 ng/ml), which inactivates Gi/Go proteins, and expression of a peptide derived from the carboxyl terminus of the β-adrenergic receptor kinase 1 (βARK1), which specifically blocks signaling mediated by the βγ subunits of G proteins, blocked the PGF2α-induced activation of MAP kinase. Ritodrine (1 μm), which is known to relax uterine muscle contraction, attenuated PGF2α-induced tyrosine phosphorylation of MAP kinase. Moreover, to examine the role of MAP kinase pathway in uterine contraction, an inhibitor of MEK activity, PD098059, was used. Although MEK inhibitor had no effect on PGF2α-induced calcium mobilization, this inhibitor partially inhibited PGF2α-induced uterine contraction. These results provide evidence that PGF2α stimulates the MAP kinase signaling pathway in cultured rat puerperal uterine myometrial cells through Gβγ protein, suggesting that this new pathway may play an important role in the biological action of PGF2α on these cells.


2021 ◽  
Vol 14 (8) ◽  
pp. e243264
Author(s):  
Chung-Shien Lee ◽  
Emily Miao ◽  
Kasturi Das ◽  
Nagashree Seetharamu

BRAF (v-raf murine sarcoma viral oncogene homolog B1) and MEK (mitogen-activated protein kinase kinase) inhibitors have been shown to improve clinical outcomes in tumours presenting with mutations in the BRAF gene. The most common form of BRAF mutation is V600E/K and has been shown to occur in thyroid cancers. Treatment data for patients harbouring less frequent BRAF mutations are limited. In vitro studies have shown that mutations in codons 599–601 increase kinase activity similar to that in V600E mutations, which suggests that BRAF and MEK inhibitors could be an effective treatment option. Here, we report a case of a patient with thyroid carcinoma harbouring a rare amino acid insertion in codon 599 of the BRAF gene (T599_V600insT) treated with a BRAF and MEK inhibitor.


2020 ◽  
Vol 21 (6) ◽  
pp. 2167
Author(s):  
Jingxuan Zhu ◽  
Congcong Li ◽  
Hengzheng Yang ◽  
Xiaoqing Guo ◽  
Tianci Huang ◽  
...  

Activation of the mitogen-activated protein kinase (MAPK) signaling pathway regulated by human MAP kinase 1 (MEK1) is associated with the carcinogenesis and progression of numerous cancers. In addition, two active mutations (P124S and E203K) have been reported to enhance the activity of MEK1, thereby eventually leading to the tumorigenesis of cancer. Trametinib is an MEK1 inhibitor for treating EML4-ALK-positive, EGFR-activated, and KRAS-mutant lung cancers. Therefore, in this study, molecular docking and molecular dynamic (MD) simulations were performed to explore the effects of inactive/active mutations (A52V/P124S and E203K) on the conformational changes of MEK1 and the changes in the interaction of MEK1 with trametinib. Moreover, steered molecular dynamic (SMD) simulations were further utilized to compare the dissociation processes of trametinib from the wild-type (WT) MEK1 and two active mutants (P124S and E203K). As a result, trametinib had stronger interactions with the non-active MEK1 (WT and A52V mutant) than the two active mutants (P124S and E203K). Moreover, two active mutants may make the allosteric channel of MEK1 wider and shorter than that of the non-active types (WT and A52V mutant). Hence, trametinib could dissociate from the active mutants (P124S and E203K) more easily compared with the WT MEK1. In summary, our theoretical results demonstrated that the active mutations may attenuate the inhibitory effects of MEK inhibitor (trametinib) on MEK1, which could be crucial clues for future anti-cancer treatment.


2019 ◽  
Vol 14 (1) ◽  
pp. 133-140
Author(s):  
Rui-Xia Chang ◽  
Ai-Ling Cui ◽  
Lu Dong ◽  
Su-Ping Guan ◽  
Ling-Yan Jiang ◽  
...  

AbstractRAS protein activator like-1 (RASAL1) exists in numerous human tissues and has been commonly demonstrated to act as a tumor suppressor in several cancers. This study aimed to identify the functional characteristics of RASAL1 in ovarian adenocarcinoma and a potential mechanism of action. We analyzed RASAL1 gene expression in ovarian adenocarcinoma samples and normal samples gained from the GEO and Oncomine databases respectively. Then the relationship between RASAL1 expression and overall survival (OS) was assessed using the Kaplan-Meier method. Furthermore, the biological effect of RASAL1 in ovarian adenocarcinoma cell lines was assessed by Quantitative real time-PCR (qRT-PCR), Cell Counting Kit-8 (CCK-8), western blot, wound healing and transwell assay. The statistical analysis showed patients with higher RASAL1 expression correlated with worse OS. The in vitro assays suggested knockdown of RASAL1 could inhibit cell proliferation, cell invasion and migration of ovarian adenocarcinoma. Moreover, the key proteins in the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) signaling pathway were also decreased in ovarian adenocarcinoma cells with RASAL1 silencing. These findings provide promising evidence that RASAL1 may be not only a powerful biomarker but also an effective therapeutic target of ovarian adenocarcinoma.


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