MK-2206, an AKT inhibitor, promotes caspase-independent cell death and inhibits leiomyoma growth

The Role and Mechanism of TRIM Proteins in Gastric Cancer

Tripartite motif (TRIM) family proteins, distinguished by their N-terminal region that includes a Really Interesting New Gene (RING) domain with E3 ligase activity, two B-box domains, and a coiled-coil region, have been recognized as significant contributors in carcinogenesis, primarily via the ubiquitin-proteasome system (UPS) for degrading proteins. Mechanistically, these proteins modulate a variety of signaling pathways, including Wnt/β-catenin, PI3K/AKT, and TGF-β/Smad, contributing to cellular regulation, and also impact cellular activities through non-signaling mechanisms, including modulation of gene transcription, protein degradation, and stability via protein-protein interactions. Currently, growing evidence indicates that TRIM proteins emerge as potential regulators in gastric cancer, exhibiting both tumor-suppressive and oncogenic roles. Given their critical involvement in cellular processes and the notable challenges of gastric cancer, exploring the specific contributions of TRIM proteins to this disease is necessary. Consequently, this review elucidates the roles and mechanisms of TRIM proteins in gastric cancer, emphasizing their potential as therapeutic targets and prognostic factors.

New AKT-dependent mechanisms of anti-COVID-19 action of high-CBD Cannabis sativa extracts

COVID-19 is caused by the SARS-CoV-2 virus, which enters target cells via interactions with ACE2 and TMPRSS2. Here, we show AKT serine/threonine kinase-dependent epigenetic control of ACE2 and TMPRSS2 expression by high-cannabidiol (CBD) cannabis extracts and their individual components. CBD alone and extracts #1, #5, #7, and #129 downregulated ACE2 and TMPRSS2 in lung fibroblast WI-38 cells through AKT-mediated inhibition. miR-200c-3p and let-7a-5p were two contributing miRNAs in CBD-mediated suppression of ACE2 and TMPRSS2. CBD and terpene PTWT2.2 profoundly inhibited ACE2 and TMPRSS2 expression, both individually and in combination. Extracts #1, #5, #7, and #169 suppressed COX2 expression and remarkably attenuated TNFα/IFNγ-triggered induction of proinflammatory factors IL-6 and IL-8 by AKT pathway. The most abundant molecules present in extracts #1 and #7 modulated the expression of COX2, IL-6, and IL-8 both individually and in combination. These results reveal that high-CBD cannabis extracts attenuated ACE2 and TMPRSS2 expression and the induction of inflammatory mediators COX2, IL-6, and IL-8 via the AKT pathway, highlighting their potential anti-COVID-19 features.

Regulation of AKT Signaling in Mouse Uterus

17β-estradiol (E2) treatment of ovariectomized adult mice stimulates the uterine PI3K-AKT signaling pathway and epithelial proliferation through estrogen receptor 1 (ESR1). However, epithelial proliferation occurs independently of E2/ESR1 signaling in neonatal uteri. Similarly, estrogen-independent uterine epithelial proliferation is seen in adulthood in mice lacking Ezh2, critical for histone methylation, and in wild-type (WT) mice treated neonatally with estrogen. The role of AKT in estrogen-independent uterine epithelial proliferation was the focus of this study. Expression of the catalytically active phosphorylated form of AKT (p-AKT) and epithelial proliferation were high in estrogen receptor 1 knockout and WT mice at postnatal day 6, when E2 concentrations were low, indicating that neither ESR1 nor E2 are essential for p-AKT expression and epithelial proliferation in these mice. However, p-AKT levels and proliferation remained estrogen responsive in preweaning WT mice. Expression of p-AKT and proliferation were both high in uterine luminal epithelium of mice estrogenized neonatally and ovariectomized during adulthood. Increased expression of phosphorylated (inactive) EZH2 was also observed. Consistent with this, Ezh2 conditional knockout mice show ovary-independent uterine epithelial proliferation and high epithelial p-AKT. Thus, adult p-AKT expression is constitutive and E2/ESR1 independent in both model systems. Finally, E2-induced p-AKT expression and normal uterine proliferation did not occur in mice lacking membrane (m)ESR1, indicating a key role for membrane ESR1 in AKT activation. These findings emphasize the importance of AKT activation in promoting uterine epithelial proliferation even when that proliferation is not E2/ESR1 dependent and further indicate that p-AKT can be uncoupled from E2/ESR1 signaling in several experimental scenarios.

Simvastatin modulates estrogen signaling in uterine leiomyoma via regulating receptor palmitoylation, trafficking and degradation

Uterine leiomyomas or fibroids are the most common tumors of the female reproductive tract. Estrogen (E2), a steroid-derived hormone, and its receptors (ERs), particularly ER-α, are important drivers for the development and growth of leiomyomas. We previously demonstrated that simvastatin, a drug used for hyperlipidemia, also possesses anti-leiomyoma properties. The aim of this work is to investigate the impact of simvastatin on ER-α signaling in leiomyoma cells, including its expression, downstream signaling, transcriptional activity, post-translational modification, trafficking and degradation. Primary and immortalized human uterine leiomyoma (HuLM) cells were used for in vitro experiments. Immunodeficient mice xenografted with human leiomyoma tissue explants were used for in vivo studies. Leiomyoma samples were obtained from patients enrolled in an ongoing double-blinded, phase II, randomized controlled trial. Here, we found that simvastatin significantly reduced E2-induced proliferation and PCNA expression. In addition, simvastatin reduced total ER-α expression in leiomyoma cells and altered its subcellular localization by inhibiting its trafficking to the plasma membrane and nucleus. Simvastatin also inhibited E2 downstream signaling, including ERK and AKT pathways, E2/ER transcriptional activity and E2-responsive genes. To explain simvastatin effects on ER-α level and trafficking, we examined its effects on ER-α post-translational processing. We noticed that simvastatin reduced ER-α palmitoylation; a required modification for its stability, trafficking to plasma membrane, and signaling. We also observed an increase in ubiquitin-mediated ER-α degradation. Importantly, we found that the effects of simvastatin on ER-α expression were recapitulated in the xenograft leiomyoma mouse model and human tissues. Thus, our data suggest that simvastatin modulates several E2/ER signaling targets with potential implications in leiomyoma therapy and beyond.

Manganese (II) chloride leads to dopaminergic neurotoxicity by promoting mitophagy through BNIP3-mediated oxidative stress in SH-SY5Y cells

Background

Manganese overexposure can induce neurotoxicity, lead to manganism and result in clinical manifestations similar to those of parkinsonism. However, the underlying molecular mechanism is still unclear. This study demonstrated that MnCl₂ induces mitophagy and leads to neurotoxicity by promoting BNIP3-mediated reactive oxygen species (ROS) generation.

Methods

Human neuroblastoma SH-SY5Y cells were used throughout our experiments. Cell viability was detected by cell proliferation/toxicity test kits. Mitochondrial membrane potential was measured by flow cytometry. ROS generation was detected using a microplate reader. Protein levels were evaluated by Western blot. Transmission electron microscopy was used to evaluate mitochondrial morphology. Co-immunoprecipitation was used to verify the interaction between BNIP3 and LC3.

Results

MnCl₂ led to loss of mitochondrial membrane potential and apoptosis of SH-SY5Y cells by enhancing expression of BNIP3 and conversion of LC3-I to LC3-II. Moreover, MnCl₂ reduced expression of the mitochondrial marker protein TOMM20 and promoted interaction between BNIP3 and LC3. The results also indicated that a decrease in BNIP3 expression reduced the mitochondrial membrane potential loss, attenuated apoptosis and reduced mitochondrial autophagosome formation in SH-SY5Y cells after MnCl₂ treatment. Finally, we found that manganese-induced ROS generation could be reversed by the antioxidant N-acetyl cysteine (NAC) or silencing BNIP3 expression.

Conclusions

BNIP3 mediates MnCl₂-induced mitophagy and neurotoxicity in dopaminergic SH-SY5Y cells through ROS. Thus, BNIP3 contributes to manganese-induced neurotoxicity by functioning as a mitophagy receptor protein.

Wnt/β-catenin signaling pathway in uterine leiomyoma: role in tumor biology and targeting opportunities

Uterine leiomyoma is the most common tumor of the female reproductive system and originates from a single transformed myometrial smooth muscle cell. Despite the immense medical, psychosocial, and financial impact, the exact underlying mechanisms of leiomyoma pathobiology are poorly understood. Alterations of signaling pathways are thought to be instrumental in leiomyoma biology. Wnt/β-catenin pathway appears to be involved in several aspects of the genesis of leiomyomas. For example, Wnt5b is overexpressed in leiomyoma, and the Wnt/β-catenin pathway appears to mediate the role of MED12 mutations, the most common mutations in leiomyoma, in tumorigenesis. Moreover, Wnt/β-catenin pathway plays a paracrine role where estrogen/progesterone treatment of mature myometrial or leiomyoma cells leads to increased expression of Wnt11 and Wnt16, which induces proliferation of leiomyoma stem cells and tumor growth. Constitutive activation of β-catenin leads to myometrial hyperplasia and leiomyoma-like lesions in animal models. Wnt/β-catenin signaling is also closely involved in mechanotransduction and extracellular matrix regulation and relevant alterations in leiomyoma, and crosstalk is noted between Wnt/β-catenin signaling and other pathways known to regulate leiomyoma development and growth such as estrogen, progesterone, TGFβ, PI3K/Akt/mTOR, Ras/Raf/MEK/ERK, IGF, Hippo, and Notch signaling. Finally, evidence suggests that inhibition of the canonical Wnt pathway using β-catenin inhibitors inhibits leiomyoma cell proliferation. Understanding the molecular mechanisms of leiomyoma development is essential for effective treatment. The specific Wnt/β-catenin pathway molecules discussed in this review constitute compelling candidates for therapeutic targeting.

Ganglioneuromas are driven by activated AKT and can be therapeutically targeted with mTOR inhibitors

Peripheral sympathetic nervous system tumors are the most common extracranial solid tumors of childhood and include neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. Surgery is the only effective therapy for ganglioneuroma, which may be challenging due to the location of the tumor and involvement of surrounding structures. Thus, there is a need for well-tolerated presurgical therapies that could reduce the size and extent of ganglioneuroma and therefore limit surgical morbidity. Here, we found that an AKT–mTOR–S6 pathway was active in human ganglioneuroma but not neuroblastoma samples. Zebrafish transgenic for constitutively activated myr-Akt2 in the sympathetic nervous system were found to develop ganglioneuroma without progression to neuroblastoma. Inhibition of the downstream AKT target, mTOR, in zebrafish with ganglioneuroma effectively reduced the tumor burden. Our results implicate activated AKT as a tumorigenic driver in ganglioneuroma. We propose a clinical trial of mTOR inhibitors as a means to shrink large ganglioneuromas before resection in order to reduce surgical morbidity.

Inhibition of Fibroblast Activation in Uterine Leiomyoma by Components of Rhizoma Curcumae and Rhizoma Sparganii

Background: The herbs Rhizoma Curcumae and Rhizoma Sparganii (RCRS) are often used in traditional Chinese medicine for the treatment of uterine leiomyoma (UL). The effectiveness of RCRS for the treatment of UL has been confirmed in our previous studies.

Purpose: This study aimed to investigate the molecular mechanism by which RCRS inhibits the activation of fibroblast activation protein (FAP) and prevents UL in rats.

Study Design and Methods: A Sprague Dawley (SD) rat model of UL was established via estrogen and progesterone load combined with external stimulation. Histological analyses, enzyme-linked immunosorbent assays, and western blotting were performed to evaluate the effect of RCRS on UL and elucidate its mechanism of action.

Results: Our data showed that the treatment of SD rats with RCRS significantly reduced the expression of extracellular matrix component collagen, FAP, and transforming growth factor beta (a FAP-activating factor) and the phosphorylation of the cell proliferation pathway-related signaling factors AKT/MEK/ERK.

Conclusion: Our results suggest that RCRS is effective in the prevention and treatment of UL in rats, and RCRS may exert its functions by inhibiting the activation of tumor-associated fibroblasts and cell proliferation and by improving the tumor extracellular matrix.

Effects of Phthalate Esters on Human Myometrial and Fibroid Cells: Cell Culture and NOD-SCID Mouse Data

Evidence is growing that phthalate esters play an important role in the pathogenesis of estrogen-dependent gynecologic diseases, especially uterine fibroids. We aimed to investigate whether in vitro treatment with di-(2-ethylhexyl)-phthalate (DEHP) affects angiogenesis, proliferation, and apoptosis in uterine fibroids. To ascertain this, we evaluated vascular endothelial growth factor (VEGF) expression and AKT/ERT phosphorylation and compared the fibroid volume between nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice fed with and without DEHP. VEGF expression was measured using enzyme-linked immunosorbent assay, and AKT/ERK phosphorylation was analyzed by western blot analysis in human myometrial and fibroid cells. The volume of the fibroid tissues implanted to NOD/SCID mice was measured, and the expression of collagen type I protein, Ki-67, proliferating cell nuclear antigen, and B cell lymphoma 2 were analyzed using immunohistochemistry. We could see significant increases in VEGF expression and AKT phosphorylation in human myometrial and fibroid cells treated with DEHP. The volume of the fibroid tissues was significantly increased in NOD/SCID mice fed with DEHP, which was accompanied by increased expression of collagen type I and AKT phosphorylation. Taken together, these results suggest that exposure to phthalate esters may influence uterine fibroid pathogenesis by increasing VEGF and collagen expression and upregulating AKT phosphorylation.

PI3K/AKT/mTOR signaling in gastric cancer: Epigenetics and beyond

PI3K/AKT/mTOR pathway is one of the most important signaling pathways involved in normal cellular processes. Its aberrant activation modulates autophagy, epithelial-mesenchymal transition, apoptosis, chemoresistance, and metastasis in many human cancers. Emerging evidence demonstrates that some infections as well as epigenetic regulatory mechanisms can control PI3K/AKT/mTOR signaling pathway. In this review, we focused on the role of this pathway in gastric cancer development, prognosis, and metastasis, with an emphasis on epigenetic alterations including DNA methylation, histone modifications, and post-transcriptional modulations through non-coding RNAs fluctuations as well as H. pylori and Epstein-Barr virus infections. Finally, we reviewed different molecular targets and therapeutic agents in clinical trials as a potential strategy for gastric cancer treatment through the PI3K/AKT/mTOR pathway.

SIRT1 promotes pulmonary artery endothelial cell proliferation by targeting the Akt signaling pathway

Pulmonary arterial hypertension (PAH) is a disease characterized by a progressive increase in pulmonary vascular resistance and obliterative pulmonary vascular remodeling; however, the pathogenesis of the disease is not completely understood. Sirtuin 1 (SIRT1) is a histone deacetylase involved in cell survival and metabolism. The present study explored the potential role of SIRT1 in human pulmonary arterial endothelial cells (HPAECs) under hypoxic conditions. In vitro HPAECs were cultured and exposed to hypoxic conditions. Subsequently, SIRT1 expression levels were measured via western blotting, the generation of reactive oxygen species (ROS) was evaluated, and the interaction between SIRT1 and Akt was assessed via reverse transcription-quantitative PCR and western blotting. In addition, the effects of SIRT1 on cell proliferation and apoptosis were also investigated. The results indicated that hypoxia induced SIRT1 expression in pulmonary arterial endothelial cells, which may be associated with ROS generation. SIRT1 expression activated the Akt signaling pathway, which increased the expression levels of Bcl-2 and hypoxia-inducible factor-1 in HPAECs. Moreover, SIRT1 promoted HPAEC proliferation and inhibited HPAEC apoptosis. ROS generation enhanced the SIRT1/Akt axis, which was essential for epithelial cell injury under hypoxic conditions. Therefore, blocking SIRT1 may reduce hypoxia-induced pathological damage in HPAECs.

Activation of protein kinase B by WNT4 as a regulator of uterine leiomyoma stem cell function

OBJECTIVE

To investigate the functional interaction between the Wnt/β-catenin and protein kinase B (Akt) pathways in leiomyoma stem cells (LSC).

DESIGN

Laboratory study.

SETTING

Research laboratory.

PATIENT(S)

Premenopausal women (n = 36; age range: 28 to 49 years) undergoing hysterectomy or myomectomy for leiomyoma.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Gene expression, protein phosphorylation, and cell proliferation.

RESULT(S)

Cells from human leiomyoma tissues were sorted by fluorescence-activated cell sorting (FACS) into three populations: LSC, intermediate cells (LIC), and differentiated cells (LDC) with the function of the Wnt/β-catenin and Akt signaling pathways in leiomyoma cells evaluated using real-time quantitative polymerase chain reaction and immunoblot analyses. The Wnt/β-catenin signaling pathway components were differentially expressed in each leiomyoma cell population. WNT4 was distinctly overexpressed in LIC, and its receptor FZD6 was primarily expressed in LSC. WNT4 stimulated Akt phosphorylation, activated β-catenin, and increased primary leiomyoma cell proliferation. These stimulatory effects were abolished by cotreatment with the Akt inhibitor, MK-2206. WNT4 up-regulated the expression of pro-proliferative genes, c-Myc and cyclin D1, specifically in LSC; this was also abrogated by Akt inhibition.

CONCLUSION(S)

Our data suggest that WNT4 regulates LSC proliferation via Akt-dependent β-catenin activation, representing a key step toward a better understanding of LSC regulation and potentially novel therapeutic targets.

Neuroblastoma-targeted nanoparticles and novel nanotechnology-based treatment methods

Neuroblastoma is a complicated pediatric tumor, originating from the neural crest, which is the most prevalent in adrenal glands, but may rarely be seen in some other tissues as well. Studies are focused on developing new strategies through novel chemo- and immuno-therapeutic drug targets. Different types of oncogenes such as MYCN, tumor suppressor genes such as p53, and some structural genes such as vascular endothelial growth factor are considered as targets for neuroblastoma therapy. The individual expression patterns in NB cells make them appropriate for this purpose. The combined effect of nano-drug delivery systems and specific drug targets will result in lower systemic side effects, prolonged therapeutic effects, and improvements in the pharmacokinetic properties of the drugs. Some of these novel drug delivery systems with a focus on liposomes as carriers are also discussed. In this review, genes and protein products that are beneficial as drug targets in the treatment of neuroblastoma have been discussed.

Targeting autophagy-related protein kinases for potential therapeutic purpose

Autophagy, defined as a scavenging process of protein aggregates and damaged organelles mediated by lysosomes, plays a significant role in the quality control of macromolecules and organelles. Since protein kinases are integral to the autophagy process, it is critically important to understand the role of kinases in autophagic regulation. At present, intervention of autophagic processes by small-molecule modulators targeting specific kinases has becoming a reasonable and prevalent strategy for treating several varieties of human disease, especially cancer. In this review, we describe the role of some autophagy-related kinase targets and kinase-mediated phosphorylation mechanisms in autophagy regulation. We also summarize the small-molecule kinase inhibitors/activators of these targets, highlighting the opportunities of these new therapeutic agents.

MiR-150-5p May Contribute to Pathogenesis of Human Leiomyoma via Regulation of the Akt/p27Kip1 Pathway In Vitro

Uterine leiomyoma is found in ~50–80% of women of a reproductive age and is the most common reason for hysterectomy. Recently, posttranscriptional gene silencing by microRNAs (miRs) has been reported as a mechanism for regulating gene expression stability in the pathogenesis of uterine leiomyomas. In this study, miR microarray analysis of leiomyomas and paired myometrial tissue revealed numerous aberrantly expressed miRs, including miR-150. In functional assays, transfection with miR-150 mimic resulted in decreased migration and fibrosis, implying an inhibition of leiomyoma growth. To identify the target genes of miR-150 in leiomyoma, gene set analysis and network analysis were performed. To overcome the limitations of in silico analysis, changes in expression levels of hallmark genes in leiomyoma after transfection with a miR-150 mimic were also evaluated using qRT-PCR. As a result, the Akt/p27^Kip1 pathway was presumed to be one of the target pathways of miR-150. After transfecting cultured leiomyoma cells with the miR-150 mimic, expression levels of its target gene Akt decreased, whereas those of p27^Kip1 increased significantly. Our results suggest that miR-150 affects the cell cycle regulation in uterine leiomyoma through the Akt/p27^Kip1 pathway.

Comparative analysis of AKT and the related biomarkers in uterine leiomyomas with MED12, HMGA2, and FH mutations

Uterine leiomyomas (ULM) are histologically and molecularly heterogeneous and clinically they grow at vastly different rates. Several driver gene mutations have been identified in ULM, including MED12 mutations, HMGA2 overexpression, and biallelic FH inactivation. ULM with different driver mutant genes may use different molecular pathways, but currently no clear correlation between gene mutations and growth related pathways has been established. To better define this relationship, we collected ULM with MED12 (n = 25), HMGA2 (n = 15), and FH (n = 27) mutations and examined the sex steroid hormone, cell cycle, and AKT pathway genes by immunohistochemistry. While ER and PR were highly expressed in all types of ULM, FH ULM showed lower ER expression and higher PR expression. HMGA2 tumors had significantly higher levels of AKT signaling and mitogenic activity than other ULM types. HMGA2 activated AKT signaling through upregulation of IGF2BP2. Silencing HMGA2 in ULM cells resulted in downregulation of AKT and upregulation of p16 and p21, which eventually led to cell senescence. HMGA2 overexpression in ULM is not only related to tumor development but also plays a role in controlling cellular proliferation through the AKT pathway.

Oxidative stress-induced miRNAs modulate AKT signaling and promote cellular senescence in uterine leiomyoma

Uterine leiomyomas (ULM) grow under high oxidative stress due to a hypoxic microenvironment and defects in redox metabolism. AKT is one major pathway activated by reactive oxygen species (ROS) that maintains ULM growth and survival. We previously reported that AKT inactivated by AKT inhibitors can significantly induce cellular senescence in ULM cells. Since some miRNAs are induced by AKT inhibitors in an ROS-dependent manner, we proposed that these miRNAs may modulate AKT function and cellular senescence in ULM. We therefore established ex vivo models of a three-dimensional ULM spheroid culture system to study the role of miRNAs in cellular senescence. Four miRNAs, miR-29b, miR-181a, miR-182, and miR-200c, were found to induce cellular senescence in primary ULM and myometrium spheroid cultures when stably overexpressed. miR-181a and miR-182 were found to repress AKT3 and CCND2, respectively. Correspondingly, RNAi of AKT3 or CCND2 also induced cellular senescence and G0/G1 arrest. Thus, miR-181a and miR-182 may drive cellular senescence in ULM by repressing AKT3 and CCND2 activity, respectively. We further demonstrated that senescent ULM cells can be effectively removed by BH3 mimetic ABT263, which provides a new therapeutic venue for the treatment of ULM. Our findings suggest that miRNAs are potent modulators in regulating the ROS-AKT-cell cycle axis in uterine leiomyoma.

KEY MESSAGES

A subset of oxidative stress-induced miRNAs is involved in AKT signaling in uterine leiomyoma. Overexpression of miR-181a and miR-182 resulted in cellular senescence in leiomyoma through repression of AKT3 and CCND2, respectively. Silencing of AKT3 and CCND2 drives leiomyoma cell into senescence and cycle arrest. Application of our newly developed 3D leiomyoma spheroids can provide a quick and reliable ex vivo model for cytopathologic and functional analysis. BH3 mimetics can effectively reduce the viability of miRNA-mediated senescent cells in leiomyoma.

Concurrent interactome and metabolome analysis reveals role of AKT1 in central carbon metabolism

Objective

Signal transduction not only initiates entry into the cell cycle, but also reprograms the cell’s metabolism. To control abnormalities in cell proliferation, both the aspects should be taken care of, thus pleiotropic signaling molecules are considered as crucial modulators. Considering this, we investigated the role of AKT1 in central carbon metabolism. The role of AKT1 has already been established in the process of cell cycle, but its contribution to the central carbon metabolism is sparsely studied.

Results

To address this, we combined the metabolomics and proteomics approaches. In accordance to our hypothesis, we found that the AKT1 kinase activity is regulating the levels of acetyl CoA through pyruvate dehydrogenase complex. Further, the decreased levels of acetyl CoA and dependency of acetyl CoA acetyl transferase protein on AKT1 kinase activity was also found to perturb the synthesis rate of palmitic acid which is a representative of fatty acid. This was analyzed in the present study using lipid labeling method through mass spectrometry.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3364-z) contains supplementary material, which is available to authorized users.

The AKT/BCL-2 Axis Mediates Survival of Uterine Leiomyoma in a Novel 3D Spheroid Model

A deeper understanding of the pathways that drive uterine leiomyoma (ULM) growth and survival requires model systems that more closely mimic the in vivo tumors. This would provide new insights into developing effective therapeutic strategies for these common benign tumors of childbearing-aged women. In this study, we examined the role of BCL-2 in mediating ULM survival in the context of increased protein kinase B (AKT) and oxidative stress using a three-dimensional (3D), spheroid-based model that more closely resembles the native ULM tumor microenvironment. Human primary cells from matched myometrium (MM) and ULM tissues were used to establish spheroid cultures in vitro. Histological and immunohistochemical methods were used to assess the spheroid architecture and characteristics. Viability assays for 3D cultures were used to evaluate their response to BH3 mimetics and the superoxide inducer, paraquat (PQ). Primary MM and ULM cells formed spheroids in culture. Notably, ULM spheroids exhibited low proliferation, increased oxidative stress, and secretion of interstitial collagen. Knockdown studies revealed that AKT sustained BCL-2 expression in ULM. The targeting of BCL-2 with BH3 mimetics effectively reduced viability and induced apoptosis in a subset of ULM spheroids. ULM spheroids that did not respond to BH3 mimetics alone responded to combination treatment with PQ. In conclusion, BCL-2 mediates AKT survival of ULM, providing compelling evidence for further evaluation of BH3 mimetics for ULM treatment. ULM spheroids recapitulated intrinsic features of the native ULM tumor microenvironment and can be used as a model for preclinical testing of potential therapeutic options for ULM.

Novel 3D Liquid Cell Culture Method for Anchorage-independent Cell Growth, Cell Imaging and Automated Drug Screening

Cells grown in three-dimensional (3D) cultures are more likely to have native cell-cell and cell-matrix interactions than in 2D cultures that impose mechanical constraints to cells. However, most 3D cultures utilise gel matrix which, while serving as a scaffold, limits application due to its solid and opaque nature and inconsistency in cell exposure to exogenous signals. In 3D culture without gel matrix, cells tend to adhere to each other and form clumps with necrotic zone at the centre, making them unsuitable for analyses. Here we report that addition of low-molecular-weight agar named LA717 to culture media allows cells to grow as dispersed clonal spheroids in 3D. LA717 maintains cells dispersed and settled to the bottom of the medium while keeping the medium clear with little additional viscosity, making it suitable for microscopic observation. Importantly, cancer spheroids formed in LA717-containing medium show higher sensitivity to anti-cancer drugs such as Trametinib and MK-2206 that are not as effective in 2D. Because of the small and consistent size of spheroids, cell viability and drug toxicity are readily detectable in automated imaging analysis. These results demonstrate that LA717 offers a novel 3D culture system with great in vivo reflection and practicality.

Foxo-dependent Par-4 Upregulation Prevents Long-term Survival of Residual Cells Following PI3K-Akt Inhibition

Tumor recurrence is a leading cause of death and is thought to arise from a population of residual cells that survive treatment. These residual cancer cells can persist, locally or at distant sites, for years or decades. Therefore, understanding the pathways that regulate residual cancer cell survival may suggest opportunities for targeting these cells to prevent recurrence. Previously, it was observed that the proapoptotic protein (PAWR/Par-4) negatively regulates residual cell survival and recurrence in mice and humans. However, the mechanistic underpinnings on how Par-4 expression is regulated are unclear. Here, it is demonstrated that Par-4 is transcriptionally upregulated following treatment with multiple drugs targeting the PI3K-Akt-mTOR signaling pathway, and identify the Forkhead family of transcription factors as mediators of this upregulation. Mechanistically, Foxo3a directly binds to the Par-4 promoter and activates its transcription following inhibition of the PI3K-Akt pathway. This Foxo-dependent Par-4 upregulation limits the long-term survival of residual cells following treatment with therapeutics that target the PI3K-Akt pathway. Taken together, these results indicate that residual breast cancer tumor cell survival and recurrence requires circumventing Foxo-driven Par-4 upregulation and suggest that approaches to enforce Par-4 expression may prevent residual cell survival and recurrence. Mol Cancer Res; 16(4); 599-609. ©2018 AACR.

Progesterone Receptor Isoforms, Nuclear Corepressor-1 and Steroid Receptor Coactivator-1 and B-Cell Lymphoma 2 and Akt and Akt Phosphorylation Status in Uterine Myomas after Ulipristal Acetate Treatment: A Systematic Immunohistochemical Evaluation

OBJECTIVE

To investigate whether ulipristal acetate (UPA) treatment modifies the expression of progesterone receptor (PR), its nuclear cofactors steroid receptor coactivator-1 (SRC1) and nuclear corepressor-1 (NCoR1), prosurvival factor B-cell lymphoma 2 (Bcl-2), and Akt in uterine myomas.

PATIENTS

Prospective study of 59 women with symptomatic myomas undergoing myomectomy. Forty-two patients were treated preoperatively with UPA; the remaining 17 were not and they served as controls.

METHOD

Tissue microarrays were obtained from surgical specimens and immunohistochemistry was performed. Blinded quantification of expression of PR (PR-A vs. PR-B), coactivator SRC1 and corepressor NCoR1, and prosurvival factor Bcl-2, and Akt and evaluation of Akt phosphorylation levels.

RESULTS

Compared with the control group, UPA does not alter PR protein levels or expression patterns in myomas, and the PR-A/PR-B ratio was similar, as well as cytoplasmic or nuclear expression of cofactors SRC1 and NCoR1. Bcl-2 was heterogeneously expressed throughout the samples and no significant modification in expression was evidenced. No significant difference was found in Akt expression and phosphorylation between treated and untreated myomas.

CONCLUSION

This study did not find any significant change in the expression of the studied factors in myomas after UPA exposure. In conclusion, various theories on myomas cells proposed on the basis of in vitro studies are not supported in vivo.

The allosteric AKT inhibitor, MK2206, decreases tumor growth and invasion in patient derived xenografts of endometrial cancer

The purpose of this study was to test the effect of MK2206, an allosteric inhibitor of AKT, on the growth and invasion of patient-derived xenografts (PDX) of endometrial cancer. Three PDX lines, USC1 (uterine serous), EEC2 (endometrioid grade 2) and EEC4 (endometrioid grade 3) of endometrial cancer were grafted under the renal capsule of NSG mice. After 2 weeks of tumor growth the mice were treated with vehicle or 120mg/kg MK2206 twice a week for 3 weeks. Growth of all 3 PDX lines of different type and grade was significantly inhibited in response to MK2206 compared with vehicle control. Histological analysis revealed invasion and spread of EEC2 and EEC4 tumors were significantly decreased with MK2206 treatment. Immunohistochemical analysis showed a decrease in Ki67 in EEC2 upon MK2206 treatment, while USC1 and EEC4 tumors did not show differences in Ki67 levels. PR levels were evident in EEC2 which dramatically increased upon MK2206 treatment. In vitro analysis of EEC4 and AN3CA cells showed a dose-dependent decrease in p(Ser473)-AKT and p(Thr308)-AKT with MK2206. Invasion of EEC4 and AN3CA cells also significantly decreased after 36h and 72h of MK2206 treatment. PDX tumors provide an appropriate model for the testing of compounds that incorporates the heterogeneous nature of endometrial cancer. Further studies to determine efficacy of MK2206 alone or in combination with other compounds can also identify predictors of response to these pathway inhibitors.

Dysfunctional MnSOD leads to redox dysregulation and activation of prosurvival AKT signaling in uterine leiomyomas

AKT signaling promotes cell growth and survival and is often dysregulated via multiple mechanisms in different types of cancer, including uterine leiomyomas (ULMs). ULMs are highly prevalent fibrotic tumors that arise from the smooth muscular layer of the uterus, the myometrium (MM). ULMs pose a major public health issue because they can cause severe morbidity and poor pregnancy outcomes. ‬We investigate the mechanisms driving ULM growth and survival via aberrant activation of AKT. We demonstrate that an acetylation-mediated impairment of the manganese superoxide dismutase (MnSOD) activity is prevalent in ULM cells compared to the normal-matched MM from the same patients. This impairment increases the levels of superoxide and oxidative stress, which activate AKT via oxidative inactivation of the phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Redox activation of AKT promotes ULM cell survival under conditions of moderate but persistent oxidative stress that are compatible with ULM's prooxidative microenvironment. Moreover, because of impaired MnSOD activity, ULM cells are sensitive to high levels of reactive oxygen species (ROS) and superoxide-generating compounds, resulting in decreased ULM cell viability. On the contrary, MM cells with functional MnSOD are more resistant to high levels of oxidants. This study demonstrates a causative role of acetylation-mediated MnSOD dysfunction in activating prosurvival AKT signaling in ULMs. The specific AKT and redox states of ULM cells provide a potential novel therapeutic rationale to selectively target ULM cells because of their defective ROS-scavenging system.‬‬‬‬‬‬‬‬.

Targeting leiomyomas with all-trans-retinoic acid at phosphoinositide 3-kinase pathway suppression: Effective roles of β-catenin and of signaling interactions

AIM

Leiomyomas, monoclonal tumors developed by the transformation of myometrium somatic stem cells, are a major health concern that can severely impair quality of life. Pathological alterations of signaling pathways have been recognized as a key feature in a variety of human diseases. Our objective was to analyze treatment with all-trans-retinoic acid (ATRA) by suppression of the phosphoinositide 3-kinase (PI3K) pathway on growth, signaling pattern and interactions among PI3K/B-cell lymphoma 2 (Bcl2)/retinol leiomyoma proteins.

METHODS

Cultures of paired myometrium and leiomyoma cells from premenopausal women undergoing hysterectomy were collected. Western blot and analysis of variance were used for analysis.

RESULTS

Significant differences were detected between treatment with ATRA alone or with LY294002 (a PI3K growth suppressor) in response to treatment and among cell samples and cell numbers. Leiomyoma cells were less affected. Immunochemical analysis of signaling patterns demonstrated that treatments affected most of the examined protein levels differently. Significant differences between the cell type responses to treatment in pyruvate phosphate dikinase 1 (pPDK1), Bad and pβ-catenin levels were identified. The pβ-catenin level showed highly significant interaction between response to treatment and cell type.

CONCLUSIONS

ATRA treatment on PI3K pathway suppression significantly affected growth, signaling pattern and interactions among PI3K/Bcl2/retinol proteins involved in the growth, survival and apoptosis of leiomyomas. Interpretation of our results suggests that increasing knowledge of the role of signaling interplay in the pathogenesis of leiomyomas may present an opportunity to use specific signal transduction inhibitors for treating and preventing this disorder.

Akt regulates progesterone receptor B-dependent transcription and angiogenesis in endometrial cancer cells

Progestins have long been used clinically for the treatment of endometrial cancers, however, the response rates to progestin therapy vary and the molecular mechanisms behind progestin insensitivity are poorly understood. We hypothesized that in PTEN mutated endometrial cancers, hyperactive Akt signaling downregulates Progesterone Receptor B (PRB) transcriptional activity, leading to overall impaired progestin responses. We report that inhibition of Akt with the Akt inhibitor, MK-2206 (MK), in conjunction with progestin (R5020) treatment, is sufficient to upregulate a subset of PRB target genes in Ishikawa cells stably expressing PRB (PRB-Ishikawa). Through gene ontology analysis of Akt-regulated PRB target genes, angiogenesis was found to be the principle process regulated by Akt-PRB. To further interrogate the mechanism by which Akt modulates PRB transcriptional activity, ChIP-Mass Spectrometry was performed to identify potential cofactors that differentially interact with PRB in the presence of the R5020 and MK+R5020. 14-3-3σ was identified as a protein enriched in the MK+R5020 dataset, and it was demonstrated that 14-3-3σ is required for the upregulation in PRB target gene expression following inhibition of Akt. In order to determine the ramifications of MK+R5020 treatment on angiogenesis, in vitro assays were performed and combinatorial MK+R5020 treatment significantly decreased endothelial cell invasion and tube formation more than MK or R5020 treatment alone. Furthermore, we found that combinatorial MK-2206+Progesterone treatments decreased angiogenesis and proliferation in the Pten^d/d conditional mouse model of endometrial cancer. Taken together, these findings suggest that a combinatorial therapeutic approach utilizing Akt inhibitors with progestins may improve the efficacy of progestin therapy for the treatment of endometrial cancer.

Clinical relevance of autophagic therapy in cancer: Investigating the current trends, challenges, and future prospects

Oncophagy (cancer-related autophagy) has a complex dual character at different stages of tumor progression. It remains an important clinical problem to unravel the reasons that propel the shift in the role of oncophagy from tumor inhibition to a protective mechanism that shields full-blown malignancy. Most treatment strategies emphasize curbing protective oncophagy while triggering the oncophagy that is lethal to tumor cells. In this review, we focus on the trends in current therapeutics as well as various challenges in clinical trials to address the oncophagic dilemma and evaluate the potential of these developing therapies. A detailed analysis of the clinical and pre-clinical scenario of the anticancer medicines highlights the various inducers and inhibitors of autophagy. The ways in which tumor stage, the microenvironment and combination drug treatment continue to play an important tactical role are discussed. Moreover, autophagy targets also play a crucial role in developing the best possible solution to this oncophagy paradox. In this review, we provide a comprehensive update on the current clinical impact of autophagy-based cancer therapeutic drugs and try to lessen the gap between translational medicine and clinical science.

The Epidemiology and Genetics of Uterine Leiomyoma

Uterine leiomyomas (fibroids) are the most common benign neoplasms in premenopausal women, which confer significant morbidity during the reproductive years and represent a significant public health issue. The incidence of fibroids has been associated with African-American race, early onset of menarche, early parity, and environmental/dietary exposures. These sex steroid-responsive uterine tumors are characterized by de novo transformation of the myometrium into fibroids via excessive formation of the extracellular matrix (ECM). Cytogenic anomalies, mutations in mediator complex subunit 12 (MED 12), and aberrant DNA methylation/demethylation have been observed, but have not been reported as direct mediators of fibroid development. Recent advances in epigenetics have implied a functional role of G protein-coupled receptor 10 (GPR10) overexpression and irregular microRNA expression in the pathobiology of fibroids that require future investigation. Herein, the impact of epidemiologic and genetic factors on the incidence and development of fibroids is reviewed.

Growth factors and pathogenesis

Growth factors are relatively small and stable, secreted or membrane-bound polypeptide ligands, which play an important role in proliferation, differentiation, angiogenesis, survival, inflammation, and tissue repair, or fibrosis. They exert multiple effects through the activation of signal transduction pathways by binding to their receptors on the surface of target cells. A number of studies have demonstrated the central role of growth factors and their signaling pathways in the pathogenesis of uterine leiomyomas. Numerous differentially expressed growth factors have been identified in leiomyoma and myometrial cells. These growth factors can activate multiple signaling pathways (Smad 2/3, ERK 1/2, PI3K, and β-catenin) and regulate major cellular processes, including inflammation, proliferation, angiogenesis, and fibrosis which are linked to uterine leiomyoma development and growth. In this chapter, we discuss the role of growth factors and their signaling pathways in the pathogenesis of uterine leiomyomas.

The tumor suppressor p53 guides GluA1 homeostasis through Nedd4-2 during chronic elevation of neuronal activity

Chronic activity perturbation in neurons can trigger homeostatic mechanisms to restore the baseline function. Although the importance and dysregulation of neuronal activity homeostasis has been implicated in neurological disorders such as epilepsy, the complete signaling by which chronic changes in neuronal activity initiate the homeostatic mechanisms is unclear. We report here that the tumor suppressor p53 and its signaling are involved in neuronal activity homeostasis. Upon chronic elevation of neuronal activity in primary cortical neuron cultures, the ubiquitin E3 ligase, murine double minute- 2 (Mdm2), is phosphorylated by the kinase Akt. Phosphorylated Mdm2 triggers the degradation of p53 and subsequent induction of a p53 target gene, neural precursor cell expressed developmentally down-regulated gene 4-like (Nedd4-2). Nedd4-2 encodes another ubiquitin E3 ligase. We identified glutamate receptor subunit 1 (GluA1), subunit of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors as a novel substrate of Nedd4-2. The regulation of GluA1 level is known to be crucial for neuronal activity homeostasis. We confirmed that, by pharmacologically inhibiting Mdm2-mediated p53 degradation or genetically reducing Nedd4-2 in a mouse model, the GluA1 ubiquitination and down-regulation induced by chronically elevated neuronal activity are both attenuated. Our findings demonstrate the first direct function of p53 in neuronal homeostasis and elucidate a new mechanism by which cortical neurons respond to chronic activity perturbation.

Signaling Pathways in Leiomyoma: Understanding Pathobiology and Implications for Therapy

Uterine leiomyomas are the most common tumors of the female genital tract, affecting 50% to 70% of females by the age of 50. Despite their prevalence and enormous medical and economic impact, no effective medical treatment is currently available. This is, in part, due to the poor understanding of their underlying pathobiology. Although they are thought to start as a clonal proliferation of a single myometrial smooth muscle cell, these early cytogenetic alterations are considered insufficient for tumor development and additional complex signaling pathway alterations are crucial. These include steroids, growth factors, transforming growth factor-beta (TGF-β)/Smad; wingless-type (Wnt)/β-catenin, retinoic acid, vitamin D, and peroxisome proliferator-activated receptor γ (PPARγ). An important finding is that several of these pathways converge in a summative way. For example, mitogen-activated protein kinase (MAPK) and Akt pathways seem to act as signal integrators, incorporating input from several signaling pathways, including growth factors, estrogen and vitamin D. This underlines the multifactorial origin and complex nature of these tumors. In this review, we aim to dissect these pathways and discuss their interconnections, aberrations and role in leiomyoma pathobiology. We also aim to identify potential targets for development of novel therapeutics.

The androgen receptor mediates antiapoptotic function in myometrial cells

During pregnancy, myometrial phenotype is programmed into three characteristic stages referred to as the early proliferative, the midterm hypertrophic, and the late contractile stage. Increased myometrial growth in the early and midterm of pregnancy involves a complex process of cell proliferation, antiapoptosis and differentiation. We have previously demonstrated that the androgen receptor (AR) is required for myometrial cell proliferation by modulating IGF-1 signaling during early pregnancy. Here, we report that AR also exerts its antiapoptotic function in human myometrial cells. Enhanced AR expression protects, whereas AR silencing sensitizes myometrial cells to both intrinsic and extrinsic apoptotic stimuli. AR agonist inhibits, whereas AR antagonist induces myometrial cells to undergo apoptotic cell death. Gene microarray analysis confirms that the central functions of AR in myometrial cells are to regulate cell cycling and apoptosis through three major gene groups involving the epidermal growth factor (EGF) signaling, RNA splicing and DNA repair processes. AR mediates its antiapoptotic function through two distinct pathways. In the receptor-dependent pathway, AR is required for the expression of several protein factors within the EGF signaling pathway. Through the PI3K/Akt pathway, AR enhances the expression of the antiapoptotic protein Mcl-1. In the ligand-dependent pathway, AR agonist triggers the activation of Src kinase, which in turn phosphorylates STAT3 to increase Mcl-1 expression. We conclude from these results that the AR signaling exerts antiapoptotic function in myometrial cells, further supporting its key role in programming of myometrial phenotype.

MicroRNAs in the development and pathobiology of uterine leiomyomata: does evidence support future strategies for clinical intervention?

BACKGROUND

Human leiomyomata (fibroids) are benign tumors of the uterus, represent the most common neoplasms of reproductive-aged women and have a prevalence of ∼70% in the general population. This disorder conveys a significant degree of morbidity and remains the leading indication for hysterectomy in the USA. Prior investigations of aberrant microRNA (miRNA) expression in various malignancies have provided invaluable insight into the role of this class of small non-coding RNAs in tumor growth. Evidence of irregular miRNA expression in uterine fibroids has garnered recent interest for diagnostic and therapeutic applications. Since miRNA gene targets modulate several processes implicated in the genesis of uterine fibroids, more focused investigation has the potential to elucidate the functional significance of miRNA in the genesis and pathology of the disease.

METHODS

Comprehensive electronic searches of peer reviewed published literature in PubMed (US National Library of Medicine, National Institute of Health; http://www.ncbi.nlm.nih.gov/pubmed/) were performed for content related to the biologic functions of miRNA, the roles of miRNA in human disease and studies investigating miRNA in the context of uterine leiomyomata. Herein, this article will review the current evidence supporting the use of miRNA expression profiling as an investigative tool to assess the pathobiology of uterine fibroids and will discuss potential future applications of miRNAs as biomarkers and therapeutic targets.

RESULTS

Mounting evidence supports a functional role for miRNA as either indirect or direct regulators of gene expression which impacts the pathobiology of uterine fibroids. Specifically, miRNAs let-7, 200a, 200c, 93, 106b and 21 have been implicated in cellular proliferation, apoptosis, extracellular matrix turnover, angiogenesis and inflammation. Preliminary data provide evidence to suggest that respective in vitro miRNA expression in leiomyomata and myometrium is regulated by sex steroids.

CONCLUSIONS

Collectively, the identification of aberrantly expressed miRNAs in uterine leiomyomata and accumulating data derived from mining of gene target prediction models and recent functional studies support the concept that miRNAs might impact the genesis and progression of disease. However, the specific biologic functions of differential miRNA expression have yet to be confirmed in vivo. Further functional studies and developing miRNA technology may provide the basis for future applications of miRNAs in clinical medicine as biomarkers and therapeutic targets.

Inactivation of AKT induces cellular senescence in uterine leiomyoma

Uterine leiomyomas (fibroids) are a major public health problem. Current medical treatments with GnRH analogs do not provide long-term benefit. Thus, permanent shrinkage or inhibition of fibroid growth via medical means remains a challenge. The AKT pathway is a major growth and survival pathway for fibroids. We propose that AKT inhibition results in a transient regulation of specific mechanisms that ultimately drive cells into cellular senescence or cell death. In this study, we investigated specific mechanisms of AKT inhibition that resulted in senescence. We observed that administration of MK-2206, an allosteric AKT inhibitor, increased levels of reactive oxygen species, up-regulated the microRNA miR-182 and several senescence-associated genes (including p16, p53, p21, and β-galactosidase), and drove leiomyoma cells into stress-induced premature senescence (SIPS). Moreover, induction of SIPS was mediated by HMGA2, which colocalized to senescence-associated heterochromatin foci. This study provides a conceivable molecular mechanism of SIPS by AKT inhibition in fibroids.