Short-Term Statin Therapy Induces Hepatic Insulin Resistance Through HNF4α/PAQR9/PPM1α Axis Regulated AKT Phosphorylation.

Statins, the first-line medication for dyslipidemia, are linked to an increased risk of type 2 diabetes. But exactly how statins cause diabetes is yet unknown. In this study, a developed short-term statin therapy on hyperlipidemia mice show that hepatic insulin resistance is a cause of statin-induced diabetes. Statin medication raises the expression of progesterone and adiponectin receptor 9 (PAQR9) in liver, which inhibits insulin signaling through degradation of protein phosphatase, Mg2+/Mn2+ dependent 1 (PPM1α) to activate ERK pathway. STIP1 homology and U-box containing protein 1 (STUB1) is found to mediate ubiquitination of PPM1α promoted by PAQR9. On the other hand, decreased activity of hepatocyte nuclear factor 4 alpha (HNF4α) seems to be the cause of PAQR9 expression under statin therapy. The interventions on PAQR9, including deletion of PAQR9, caloric restriction and HNF4α activation, are all effective treatments for statin-induced diabetes, while liver specific over-expression of PPM1α is another possible tactic. The results reveal the importance of HNF4α-PAQR9-STUB1-PPM1α axis in controlling the statin-induced hepatic insulin resistance, offering a fresh insight into the molecular mechanisms underlying statin therapy.

Biological Activities of Citrus-Derived Extracellular Vesicles on Human Cells: The Role of Preservation.

Extracellular vesicles (EVs) have been identified as important mediators for cell-to-cell communication. Citrus-based EVs in particular offer an excellent platform for nutraceutical delivery systems, as their endemic cargo includes micronutrients (e.g., ascorbic acid), which contribute to their antioxidant capacity. Despite being extensively investigated as to their therapeutic and diagnostic potential, their cargo is inherently unstable and thus directly affected by their storage and preservation. In this study, EVs were isolated from citrus fruit using tangential flow filtration and evaluated for their physicochemical characteristics, antioxidant activity and effects on human cells. To assess how their isolation and preservation methods affect these properties, the EVs were tested immediately after isolation (from fresh and freeze-thawed juices) or following freeze-drying. A measurable biological effect of cryoprotection on citrus-derived EVs was evident, whether during or after isolation. This was more pronounced in the cell-based assays, ranging from -4% to +32% in human skin fibroblast proliferation. Nevertheless, the effects on human cancer cells varied depending on the cell line. Although these results should be considered preliminary observations, subject to further investigation, it is safe to state that any type of preservation is expected to impact the EVs' biological activity.

Bioactive materials from berberine-treated human bone marrow mesenchymal stem cells promote alveolar bone regeneration by regulating macrophage polarization.

Alveolar bone regeneration has been strongly linked to macrophage polarization. M1 macrophages aggravate alveolar bone loss, whereas M2 macrophages reverse this process. Berberine (BBR), a natural alkaloid isolated and refined from Chinese medicinal plants, has shown therapeutic effects in treating metabolic disorders. In this study, we first discovered that culture supernatant (CS) collected from BBR-treated human bone marrow mesenchymal stem cells (HBMSCs) ameliorated periodontal alveolar bone loss. CS from the BBR-treated HBMSCs contained bioactive materials that suppressed the M1 polarization and induced the M2 polarization of macrophages in vivo and in vitro. To clarify the underlying mechanism, the bioactive materials were applied to different animal models. We discovered macrophage colony-stimulating factor (M-CSF), which regulates macrophage polarization and promotes bone formation, a key macromolecule in the CS. Injection of pure M-CSF attenuated experimental periodontal alveolar bone loss in rats. Colony-stimulating factor 1 receptor (CSF1R) inhibitor or anti-human M-CSF (M-CSF neutralizing antibody, Nab) abolished the therapeutic effects of the CS of BBR-treated HBMSCs. Moreover, AKT phosphorylation in macrophages was activated by the CS, and the AKT activator reversed the negative effect of the CSF1R inhibitor or Nab. These results suggest that the CS of BBR-treated HBMSCs modulates macrophage polarization via the M-CSF/AKT axis. Further studies also showed that CS of BBR-treated HBMSCs accelerated bone formation and M2 polarization in rat teeth extraction sockets. Overall, our findings established an essential role of BBR-treated HBMSCs CS and this might be the first report to show that the products of BBR-treated HBMSCs have active effects on alveolar bone regeneration.

Integrated serum pharmacochemistry and network pharmacology to explore the mechanism of Yi-Shan-Hong formula in alleviating chronic liver injury.

BACKGROUND: Chronic liver injury (CLI) is a complex condition that requires effective therapeutic interventions. The Yi-Shan-Hong (YSH) formula is an empirically derived remedy that has shown effectiveness and safety in the management of chronic liver damage. However, the bioactive components and multifaceted mechanisms of YSH remain inadequately understood. PURPOSE: To examine the bioactive compounds and functional processes that contribute to the therapeutic benefits of YSH against CLI. METHODS: Serum pharmacochemistry and network pharmacology were employed to identify active compounds and possible targets of YSH in CLI. In addition, YSH was also given in three doses to d-(+)-galactosamine hydrochloride (D-GalN) -induced CLI rats to test its therapeutic efficacy. RESULTS: The analysis of serum samples successfully detected 25 compounds from YSH. Searches on the databases resulted in 277 genes as being correlated with chemicals in YSH, and 397 genes associated with CLI. In vivo experiments revealed that YSH displayed a notable therapeutic impact on liver injury caused by d-GalN. This was evidenced by enhanced liver function and histopathological improvements, reduced oxidative stress response, proinflammatory factors, and fibrosis levels. Importantly, no discernible adverse effects were observed. Furthermore, the administration of YSH treatment reversed the activation of AKT phosphorylation caused by d-GalN, aligning with the findings of the network pharmacology study. CONCLUSION: These findings provide preclinical evidence of YSH's therapeutic value in CLI and highlight its hepatoprotective action via the PI3K/AKT signaling pathway.

Structurally diverse amides from Chloranthus henryi var. hupehensis and their anti-inflammatory activities by blocking Akt phosphorylation.

Eleven new amides, four racemic pairs of (±)-chlorahupetamides A, B, D, E (1, 2, 4, 5) and chlorahupetamides C, F, G (3, 6, 7), have been isolated from Chloranthus henryi var. hupehensis. Compounds 1-3 are the first naturally occurring dimers via an unprecedented [2 + 2] cycloaddition derived from two dissimilar cinnamic acid amides, while compounds 4 and 5 represent the first examples of lignanamides in Chloranthus; together with two new hydroxycinnamic acid amide monomers (6-7), these compounds were obtained. Their structures were characterized by nuclear magnetic resonance (NMR), electronic circular dichroism (ECD), and X-ray diffraction analysis. Meanwhile, an LPS-induced BV-2 cell inflammatory model was used to determine the potential anti-inflammatory activity of all the isolated compounds. Intriguingly, compound -1 treatment showed a much greater inhibition of TNF-α expression with an EC50 value of 1.80 µM, while compound + 1 had more advantages in reducing IL-1ß expression with an EC50 value of 19.93 µM. Moreover, compounds + 1 and -1 could significantly suppress inflammation and inhibit the Akt signaling pathway by decreasing the phosphorylated protein levels of Akt.

Effect of USP9X on Akt phosphorylation and platelet function / 中国输血杂志

【Objective】 To explore the expression of USP9X in platelets and its effect on platelet function. 【Methods】 The expression of USP9X in human and mouse was evaluated by PCR and Western blot. Platelets from young and old mice were separated and prepared, and the expression of USP9X was detected. USP9X inhibitos were used to assess the regulation of USP9X in platelet function, including aggregation, ATP release and spreading. Platelet lysates were collected in different time points to evaluate the change of phosphorylation of Akt in USP9X inhibitors treated platelets. 【Results】 Both human and mouse platelets expressed USP9X. Compared to the young mice, the old mice showed significantly enhanced expression of USP9X(P<0.05). To assess the effect of USP9X on platelet function, USP9X inhibitor was used to pre-incubate platelets for 30 min and platelet function were examined later. Results showed that USP9X inhibitor significantly decreased platelet activation including aggregation, ATP release and spreading(P<0.05). Compared to the control group, the inhibitor treated group showed a significant decrease in the spreading area after 45 minutes. The Western blot results showed a significant decrease in Akt phosphorylation levels of platelets in the USP9X inhibitor treated group. 【Conclusion】 Both human and mouse platelet express USP9X, and inhibition of USP9X decreased platelet function including aggregation, ATP release and spreading. USP9X can also influence the phosphorylation of Akt. The inhibitor of USP9X may become a potential therapeutic target for thrombosis intervention.

Lysicamine Reduces Protein Kinase B (AKT) Activation and Promotes Necrosis in Anaplastic Thyroid Cancer.

Anaplastic thyroid cancer (ATC) is an aggressive form of thyroid cancer (TC), accounting for 50% of total TC-related deaths. Although therapeutic approaches against TC have improved in recent years, the survival rate remains low, and severe adverse effects are commonly reported. However, unexplored alternatives based on natural compounds, such as lysicamine, an alkaloid found in plants with established cytotoxicity against breast and liver cancers, offer promise. Therefore, this study aimed to explore the antineoplastic effects of lysicamine in papillary TC (BCPAP) and ATC (HTH83 and KTC-2) cells. Lysicamine treatment reduced cell viability, motility, colony formation, and AKT activation while increasing the percentage of necrotic cells. The absence of caspase activity confirmed apoptosis-independent cell death. Necrostatin-1 (NEC-1)-mediated necrosome inhibition reduced lysicamine-induced necrosis in KTC-2, suggesting necroptosis induction via a reactive oxygen species (ROS)-independent mechanism. Additionally, in silico analysis predicted lysicamine target proteins, particularly those related to MAPK and TGF-ß signaling. Our study demonstrated lysicamine's potential as an antineoplastic compound in ATC cells with a proposed mechanism related to inhibiting AKT activation and inducing cell death.

Novel 5-aminopyrazoles endowed with anti-angiogenetic properties: Design, synthesis and biological evaluation.

The promising anti-angiogenetic properties of previously synthesized pyrazolyl ureas provided the rationale for the synthesis of novel 5-aminopyrazoles 2-5, differently decorated on the pyrazole nucleus. All the derivatives were tested by MTT assays and proved to be non-cytotoxic against eight different tumor cell lines and normal fibroblasts. An EdU proliferation assay was carried out on human foreskin fibroblasts and VEGF stimulated human umbilical vein endothelial cells which confirmed the absence of cytotoxicity of the compounds on human cells up to 20 µM concentration. To evaluate the influence of the newly synthesized pyrazoles on MAPK and PI3K signaling pathways, the phosphorylation of ERK1/2 and Akt was analyzed by Western blots from HFF and HUVEC cell lysates stimulated with growth factors in the presence or absence of the compounds. Pyrazoles 3b and 3c showed a significant inhibition of Akt phosphorylation in both tested cell lines with lower phosphorylation levels than the reference compound GeGe-3 in HUVEC. Furthermore, derivatives 2 and 3 appeared to strongly affect the migration of HFF cells in a wound healing assay, confirming their potential ability to interfere with the angiogenesis process. The new pyrazole library extends the structure-activity relationships of the previously isolated compounds and highlights the attractiveness of this chemical class for pathological cell migration and angiogenesis.

The effect of Banxia-houpo decoction on CUMS-induced depression by promoting M2 microglia polarization via TrkA/Akt signalling.

It has been reported that Banxia-houpo decoction (BXHPD) serves as the anti-depressant treatment for a mild and severe depressive disease with limited side effects. The present study was performed to evaluate the protective effect of BXHPD on chronic unpredicted mild stress (CUMS)-induced depression and explore its effect on TrkA/Akt-mediated microglia polarization. The CUMS procedure was carried out, and the mice were intragastrically treated with BXHPD once daily. The selective TrkA inhibitor GW441756 was applied to further investigate the role of TrkA in BXHPD-mediated microglia polarization. The behaviour test including open field test (OFT), sucrose preference test (SPT), novelty-suppressed feeding test (NSFT), tail suspension test (TST) and forced swim test (FST) was performed. The concentrations of pro-inflammatory cytokines IL-6, TNF-α, IL-1ß, IL-12 and anti-inflammatory cytokines IL-4, IL-10 were determined using Enzyme-linked immunosorbent assay. The population of Iba1+ cells and the length of microglia processes were observed under the fluorescence microscope. The mRNA expressions of Arg1, Ym1 and Fizzl1 were measured by PCR. The protein expressions of TrkA, p-Tyr490-TrkA, p-Ser473-Akt, p-Ser473-Akt1, p-Ser474-Akt2, p-CREB and Jmjd3 were detected by western blot. Our results showed that BXHPD attenuated CUMS-induced depressive-like behaviour, promoted anti-inflammatory cytokines, inhibited pro-inflammatory cytokines, suppressed microglia activation, promoted M2 phenotype-specific indices and upregulated the expressions of TrkA, p-Tyr490-TrkA, p-Ser473-Akt, p-Ser473-Akt1, p-Ser474-Akt2, p-CREB and Jmjd3. The above beneficial effect of BXHPD can be blocked by TrkA inhibitor GW441756. This work demonstrated that BXHPD exerted an anti-depressant effect by promoting M2 phenotype microglia polarization via TrkA/Akt pathway.

Calnuc-derived nesfatin-1-like peptide is an activator of tumor cell proliferation and migration.

Calnuc (nucleobindin-1, nucb1) is a Ca2+ -binding protein involved in the etiology of many human diseases. To understand the functions of calnuc, we have identified a nesfatin-1-like peptide (NLP) in its N terminus that is proteolyzed by a convertase enzyme in the secretory granules of cells. Mutational studies confirm the presence of a proteolytic cleavage site for proprotein convertase subtilisin/kexin type 1 (PCSK1). We demonstrate that NLP regulates Gαq-mediated intracellular Ca2+ dynamics, likely via a G-protein-coupled receptor. NLP treatment to carcinoma cell lines (SCC131 cells) promotes the expression of regulators of cell cycle, proliferation, and clonogenicity by the AKT/mTOR pathway. NLP is causative of augmented migration and epithelial-mesenchymal transition (EMT), illustrating its metastatic propensity and establishing its tumor promotion ability.

Inhibition of protein arginine deiminase II suppresses retinoblastoma in orthotopic transplantation in mice.

Chemotherapies are used for treating retinoblastoma; however, numerous patients suffer from recurrence or symptoms due to chemotherapy, which emphasizes the need for alternative therapeutic strategies. The present study demonstrated that protein arginine deiminase Ⅱ (PADI2) was highly expressed in human and mouse retinoblastoma tissues due to the overexpression of E2 factor (E2F). By inhibiting PADI2 activity, the expression of phosphorylated AKT was reduced, and cleaved poly (ADP­ribose) polymerase level was increased, leading to induced apoptosis. Similar results were obtained in orthotopic mouse models with reduced tumor volumes. In addition, BB­Cl­amidine showed low toxicity in vivo. These results suggested that PADI2 inhibition has potential clinical translation. Furthermore, the present study highlights the potential of epigenetic approaches to target RB1­deficient mutations at the molecular level. The current findings provide new insights into the importance of retinoblastoma intervention by managing PADI2 activity according to the treatment of specific inhibitors and depletion approaches in vitro and in orthotopic mouse models.

[Corrigendum] CXCR1 promotes malignant behavior of gastric cancer cells in vitro and in vivo in AKT and ERK1/2 phosphorylation.

Subsequently to the publication of the above article, the authors contacted the Editorial Office to explain that they had inadvertently included data from the same original source in the first row of data panels in Fig. 4B on p. 2191 (showing the results of cell migration assay experiments) to represent two differently performed experiments. Specifically, these images (second and third data panels) containing partially overlapping data corresponded to the 'Vacant­BGC823' in the empty plasmid transfection group and the background 'BGC823 cell' groups, respectively. However, the authors had retained their original data, which they presented to the office for our inspection, and were able to reassemble the data correctly in the figure. The revised version of Fig. 4, showing the replacement data for the 'Vacant­BGC823' and 'BGC823' Migration panels in Fig. 4B, is shown on the next page. The authors are grateful to the Editor of International Journal of Oncology for allowing them this opportunity to publish a Corrigendum, and all the authors agree with its publication. Furthermore, the authors apologize to the readership for any inconvenience caused. [International Journal of Oncology 48: 2184­2196, 2016; DOI: 10.3892/ijo.2016.3428].

Up-Regulation of microRNA-424 Causes an Imbalance in AKT Phosphorylation and Impairs Enteric Neural Crest Cell Migration in Hirschsprung Disease.

Insights into the role of microRNAs (miRNAs) in disease pathogenesis have made them attractive therapeutic targets, and numerous miRNAs have been functionally linked to Hirschsprung disease (HSCR), a life-threatening genetic disorder due to defective migration, proliferation, and colonization of enteric neural crest cells (ENCCs) in the gut. Recent studies have demonstrated that miR-424 strongly inhibits migration in a variety of cell types and its potential target RICTOR is essential for neural crest cell development. We therefore sought to interrogate how miR-424 and RICTOR contribute to the pathogenesis of HSCR. We utilized HSCR cases and human neural cells to evaluate the miR-424-mediated regulation of RICTOR and the downstream AKT phosphorylation. We further developed an ex vivo model to assess the effects of miR-424 on ENCC migration and proliferation. Then, single-cell atlases of gene expression in both human and mouse fetal intestines were used to determine the characteristics of RICTOR and AKT expression in the developing gut. Our findings demonstrate that miR-424 levels are markedly increased in the colonic tissues of patients with HSCR and that it regulates human neural cell migration by directly targeting RICTOR. Up-regulation of miR-424 leads to decreased AKT phosphorylation levels in a RICTOR-dependent manner, and this, in turn, impairs ENCC proliferation and migration in the developing gut. Interestingly, we further identified prominent RICTOR and AKT expressions in the enteric neurons and other types of enteric neural cells in human and mouse fetal intestines. Our present study reveals the role of the miR-424/RICTOR axis in HSCR pathogenesis and indicates that miR-424 is a promising candidate for the development of targeted therapies against HSCR.

Fine particulate matter (PM2.5)-induced pulmonary oxidative stress contributes to increases in glucose intolerance and insulin resistance in a mouse model of circadian dyssynchrony.

Results of human and animal studies independently suggest that either ambient fine particulate matter (PM2.5) air pollution exposure or a disturbed circadian rhythm (circadian dyssynchrony) are important contributing factors to the rapidly evolving type-2-diabetes (T2D) epidemic. The objective of this study is to investigate whether circadian dyssynchrony increases the susceptibility to PM2.5 and how PM2.5 affects metabolic health in circadian dyssynchrony. We examined systemic and organ-specific changes in glucose homeostasis and insulin sensitivity in mice maintained on a regular (12/12 h light/dark) or disrupted (18/6 h light/dark, light-induced circadian dyssynchrony, LICD) light cycle exposed to air or concentrated PM2.5 (CAP, 6 h/day, 30 days). Exposures during Zeitgeber ZT3-9 or ZT11-17 (Zeitgeber in circadian time, ZT0 = begin of light cycle) tested for time-of-day PM2.5 sensitivity (chronotoxicity). Mice transgenic for lung-specific overexpression of extracellular superoxide dismutase (ecSOD-Tg) were used to assess the contribution of CAP-induced pulmonary oxidative stress. Both, CAP exposure from ZT3-9 or ZT11-17, decreased glucose tolerance and insulin sensitivity in male mice with LICD, but not in female mice or in mice kept on a regular light cycle. Although changes in glucose homeostasis in CAP-exposed male mice with LICD were not associated with obesity, they were accompanied by white adipose tissue (WAT) inflammation, impaired insulin signaling in skeletal muscle and liver, and systemic and pulmonary oxidative stress. Preventing CAP-induced oxidative stress in the lungs mitigated the CAP-induced decrease in glucose tolerance and insulin sensitivity in LICD. Our results demonstrate that circadian dyssynchrony is a novel susceptibility state for PM2.5 and suggest that PM2.5 by inducing pulmonary oxidative stress increases glucose intolerance and insulin resistance in circadian dyssynchrony.

Attenuation of Skeletal Muscle Atrophy Induced by Dexamethasone in Rats by Teaghrelin Supplementation.

Muscle atrophy caused by an imbalance between the synthesis and the degradation of proteins is a syndrome commonly found in the elders. Teaghrelin, a natural compound from oolong tea, has been shown to promote cell differentiation and to inhibit dexamethasone-induced muscle atrophy in C2C12 cells. In this study, the therapeutic effects of teaghrelin on muscle atrophy were evaluated in Sprague Dawley rats treated with dexamethasone. The masses of the soleus, gastrocnemius and extensor digitorum longus muscles were reduced in dexamethasone-treated rats, and the reduction of these muscle masses was significantly attenuated when the rats were supplemented with teaghrelin. Accordingly, the level of serum creatine kinase, a marker enzyme of muscle proteolysis, was elevated in dexamethasone-treated rats, and the elevation was substantially reduced by teaghrelin supplementation. A decrease in Akt phosphorylation causing the activation of the ubiquitin-proteasome system and autophagy for protein degradation was detected in the gastrocnemius muscles of the dexamethasone-treated rats, and this signaling pathway for protein degradation was significantly inhibited by teaghrelin supplementation. Protein synthesis via the mTOR/p70S6K pathway was slowed down in the gastrocnemius muscles of the dexamethasone-treated rats and was significantly rescued after teaghrelin supplementation. Teaghrelin seemed to prevent muscle atrophy by reducing protein degradation and enhancing protein synthesis via Akt phosphorylation.

Alpha-Mangostin Reduces Pericellular Fibronectin on Suspended Tumor Cells and Therapeutically, but Not Prophylactically, Suppresses Distant Metastasis.

Major cancer deaths can be ascribed to distant metastasis to which the assembly of pericellular fibronectin (periFN) on suspended tumor cells (STCs) in the bloodstream that facilitate endothelial attachment can lead. Even though mangosteen pericarps (MP) extracts and the major component α-mangostin (α-MG) exhibit potent cancer chemopreventive properties, whether they can prophylactically and therapeutically be used as dietary nutraceuticals to prevent distant metastasis by suppressing periFN assembly on STCs within the circulation remains obscure. Immunofluorescence staining, MTT assays, flow cytometric assays, immunoblotting, and experimental metastasis mouse models were used to detect the effects of MP extracts or α-MG on periFN on STCs, tumor cell proliferation and apoptosis, the AKT activity, and tumor lung metastasis. The periFN assembly on STCs was significantly diminished upon treatments of STCs with either α-MG or MP extracts in a dose-dependent manner without inhibiting cell proliferation and viability due to increased AKT activity. Pretreatment of STCs with α-MG appeared to suppress tumor lung metastasis and prolong mouse survival rates. Oral gavage with MP extracts could therapeutically, but not prophylactically, prevent lung metastasis of STCs. We concluded that MP extracts or the major component α-MG may therapeutically serve as a potent anti-metastatic nutraceutical.

A novel lncRNA lncSAMD11-1: 1 interacts with PIP4K2A to promote endometrial decidualization by stabilizing FoxO1 nuclear localization.

Decidualization is essential for a successful pregnancy and determines embryo implantation and pregnancy maintenance. Abnormal decidualization is one of the main causes of recurrent implantation failure (RIF). Studies have shown that large amounts of long noncoding RNAs (lncRNAs) are abnormally expressed in endometrial samples from patients with RIF. However, the functional contributions of lncRNAs to decidualization in RIF have not been explored. In this study, we found that lncSAMD11-1:1 was significantly declined in the endometria of patients with RIF. The knockdown of lncSAMD11-1:1 in human endometrial stromal cells (hESCs) restrained decidualization and embryo implantation in vitro, while the overexpression of lncSAMD11-1:1 facilitated hESC decidualization and embryo implantation in vitro and ameliorated decidualization in RIF patients. Mechanistically, lncSAMD11-1:1 and phosphatidylinositol-5-phosphate 4-kinase type 2 alpha (PIP4K2A) translocated out of nucleus and bound to each other during decidualization, thereby inhibiting the phosphorylation of AKT and promoting FoxO1 nuclear localization. These data suggest that lncSAMD11-1:1 might be a critical novel lncRNA functionally required for human decidualization, and the dysregulation of lncSAMD11-1:1 in the endometrium may be a new predisposing factor of RIF.

DRD2 Agonist Cabergoline Abolished the Escape Mechanism Induced by mTOR Inhibitor Everolimus in Tumoral Pituitary Cells.

The mammalian target of rapamycin (mTOR) inhibitor everolimus has been shown to display antiproliferative effects on a wide spectrum of tumors. In vitro studies demonstrated that everolimus inhibited pituitary neuroendocrine tumor (PitNET) cell growth in a subset of patients. Sensitivity to everolimus is reduced by an escape mechanism that increases AKT phosphorylation (p-AKT), leading to pro-survival pathway activation. Dopamine receptor type 2 (DRD2) mediates a reduction of p-AKT in a subgroup of non-functioning PitNETs (NF-PitNETs) and in prolactin-secreting tumor cells (MMQ cells) through a ß-arrestin 2-dependent mechanism. The aim of this study was to investigate the efficacy of everolimus combined with DRD2 agonist cabergoline in reducing NF-PitNET primary cells and MMQ cell proliferation and to evaluate AKT phosphorylation and a possible role of ß-arrestin 2. We found that 9 out of 14 NF-PitNETs were resistant to everolimus, but the combined treatment with cabergoline inhibited cell proliferation in 7 out of 9 tumors (-31.4 ± 9.9%, p < 0.001 vs. basal) and reduced cyclin D3 expression. In the everolimus-unresponsive NF-PitNET group, everolimus determined a significant increase of p-AKT/total-AKT ratio (2.1-fold, p < 0.01, vs. basal) that was reverted by cabergoline cotreatment. To investigate the molecular mechanism involved, we used MMQ cells as a model of everolimus escape mechanism. Indeed everolimus did not affect MMQ cell proliferation and increased the p-AKT/total-AKT ratio (+1.53 ± 0.24-fold, p < 0.001 vs. basal), whereas cabergoline significantly reduced cell proliferation (-22.8 ± 6.8%, p < 0.001 vs. basal) and p-AKT. The combined treatment of everolimus and cabergoline induced a reduction of both cell proliferation (-34.8 ± 18%, p < 0.001 vs. basal and p < 0.05 vs. cabergoline alone) and p-AKT/total-AKT ratio (-34.5 ± 14%, p < 0.001 vs. basal and p < 0.05 vs. cabergoline alone). To test ß-arrestin 2 involvement, silencing experiments were performed in MMQ cells. Our data showed that the lack of ß-arrestin 2 prevented the everolimus and cabergoline cotreatment inhibitory effects on both p-AKT and cell proliferation. In conclusion, this study revealed that cabergoline might overcome the everolimus escape mechanism in NF-PitNETs and tumoral lactotrophs by inhibiting upstream AKT activation. The co-administration of cabergoline might improve mTOR inhibitor antitumoral activity, paving the way for a potential combined therapy in ß-arrestin 2-expressing NF-PitNETs or other PitNETs resistant to conventional treatments.

Regulation of bFGF-induced effects on rat aortic smooth muscle cells by ß3-adrenergic receptors.

Background: Basic fibroblast growth factor (bFGF)-mediated vascular smooth muscle cell (VSMC) proliferation and migration play an important role in vascular injury-induced neointima formation and subsequent vascular restenosis, a major event that hinders the long-term success of angioplasty. The function of ß3-adrenergic receptors (ß3-ARs) in vascular injury-induced neointima formation has not yet been defined. Objectives: Our current study explored the possible role of ß3-ARs in vascular injury-induced neointima formation by testing its effects on bFGF-induced VSMC migration and proliferation. Methods: ß3-AR expression in rat carotid arteries was examined at 14 days following a balloon catheter-induced injury. The effects of ß3-AR activation on bFGF-induced rat aortic smooth muscle cell proliferation, migration, and signaling transduction (including extracellular-signal-regulated kinase/mitogen activated protein kinase, ERK/MAPK and Protein kinase B, AKT) were tested. Results: We found that vascular injury induced upregulation of ß3-ARs in neointima. Pretreatment of VSMCs with a selective ß3-AR agonist, CL316,243 significantly potentiated bFGF-induced cell migration and proliferation, and ERK and AKT phosphorylation. Our results also revealed that suppressing phosphorylation of ERK and AKT blocked bFGF-induced cell migration and that inhibiting AKT phosphorylation reduced bFGF-mediated cell proliferation. Conclusion: Our results suggest that activation of ß3-ARs potentiates bFGF-mediated effects on VSMCs by enhancing bFGF-mediated ERK and AKT phosphorylation and that ß3-ARs may play a role in vascular injury-induced neointima formation.

Cancer-Associated Fibroblasts Promote the Upregulation of PD-L1 Expression Through Akt Phosphorylation in Colorectal Cancer.

Upregulation of immune checkpoint proteins is one of the main mechanisms for tumor immune escape. The expression of programmed death ligand-1 (PD-L1) in colorectal cancer (CRC) is higher than in normal colorectal epithelial tissue, and patients with higher PD-L1 expression have a poorer prognosis. Additionally, PD-L1 expression in CRC is affected by the tumor microenvironment (TME). As a major component of the TME, cancer-associated fibroblasts (CAFs) can act as immune regulators and generate an immunosuppressive tumor microenvironment. Therefore, we speculated that CAFs may be related to the upregulation of PD-L1 in CRC, which leads to tumor immune escape. We found that CAFs upregulate PD-L1 expression in CRC cells through AKT phosphorylation, thereby reducing the killing of CRC cells by peripheral blood mononuclear cells. The ratio of CAFs to CRC cells was positively correlated with AKT phosphorylation and the expression of PD-L1 in CRC in vitro. Consistent with the in vitro results, high CAF content and high expression of PD-L1 were negatively correlated with disease-free survival (DFS) of CRC patients. These results indicate that the upregulation of PD-L1 expression in CRC by CAFs through the activation of Akt is one of the molecular mechanisms of tumor immune escape. Thus, targeted anti-CAF therapy may help improve the efficacy of immunotherapy.