The cGAS-STING signaling in cardiovascular and metabolic diseases: Future novel target option for pharmacotherapy

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling exert essential regulatory function in microbial-and onco-immunology through the induction of cytokines, primarily type I interferons. Recently, the aberrant and deranged signaling of the cGAS-STING axis is closely implicated in multiple sterile inflammatory diseases, including heart failure, myocardial infarction, cardiac hypertrophy, nonalcoholic fatty liver diseases, aortic aneurysm and dissection, obesity, etc. This is because of the massive loads of damage-associated molecular patterns (mitochondrial DNA, DNA in extracellular vesicles) liberated from recurrent injury to metabolic cellular organelles and tissues, which are sensed by the pathway. Also, the cGAS-STING pathway crosstalk with essential intracellular homeostasis processes like apoptosis, autophagy, and regulate cellular metabolism. Targeting derailed STING signaling has become necessary for chronic inflammatory diseases. Meanwhile, excessive type I interferons signaling impact on cardiovascular and metabolic health remain entirely elusive. In this review, we summarize the intimate connection between the cGAS-STING pathway and cardiovascular and metabolic disorders. We also discuss some potential small molecule inhibitors for the pathway. This review provides insight to stimulate interest in and support future research into understanding this signaling axis in cardiovascular and metabolic tissues and diseases.

Chronic Lymphocytic Leukemia (CLL): evaluation of AKT protein kinase and microRNA gene expression related to disease pathogenesis

Abstract The present study evaluated 56 patients diagnosed with Chronic Lymphocytic Leukemia (CLL) and a control group of 44 clinically healthy subjects with no previous history of leukemia. Genetic expressions of AKT and microRNAs were evaluated by quantitative PCR (qPCR). A significant increase in AKT gene expression in patients when compared to controls was observed (p = 0.017). When the patients were stratified according to Binet subgroups, a significant difference was observed between the subgroups, with this protein kinase appearing more expressed in the B+C subgroup (p = 0.013). Regarding miRNA expression, miR-let-7b and miR-26a were reduced in CLL patients, when compared to controls. However, no significant differences were observed in these microRNA expressions between the Binet subgroups (A versus B+C). By contrast, miR-21 to miR-27a oncogenes showed no expression difference between CLL patients and controls. AKT protein kinase is involved in the signaling cascade that occurs with BCR receptor activation, leading to increased lymphocyte survival and protection against the induction of cell death in CLL. Thus, increased AKT protein kinase expression and the reduction of miR-let-7b and miR-26a, both tumor suppressors, may explain increased lymphocyte survival in CLL patients and may be promising markers for the prognostic evaluation of this disease.

A multifunctional cross-validation high-throughput screening protocol enabling the discovery of new SHP2 inhibitors

The protein tyrosine phosphatase Src homology phosphotyrosyl phosphatase 2 (SHP2) is implicated in various cancers, and targeting SHP2 has become a promising therapeutic approach. We herein described a robust cross-validation high-throughput screening protocol that combined the fluorescence-based enzyme assay and the conformation-dependent thermal shift assay for the discovery of SHP2 inhibitors. The established method can effectively exclude the false positive SHP2 inhibitors with fluorescence interference and was also successfully employed to identify new protein tyrosine phosphatase domain of SHP2 (SHP2-PTP) and allosteric inhibitors. Of note, this protocol showed potential for identifying SHP2 inhibitors against cancer-associated SHP2 mutation SHP2-E76A. After initial screening of our in-house compound library (∼2300 compounds), we identified 4 new SHP2-PTP inhibitors (0.17% hit rate) and 28 novel allosteric SHP2 inhibitors (1.22% hit rate), of which SYK-85 and WS-635 effectively inhibited SHP2-PTP (SYK-85: IC

Selective inhibition of CDK4/6: A safe and effective strategy for developing anticancer drugs

The sustained cell proliferation resulting from dysregulation of the cell cycle and activation of cyclin-dependent kinases (CDKs) is a hallmark of cancer. The inhibition of CDKs is a highly promising and attractive strategy for the development of anticancer drugs. In particular, third-generation CDK inhibitors can selectively inhibit CDK4/6 and regulate the cell cycle by suppressing the G1 to S phase transition, exhibiting a perfect balance between anticancer efficacy and general toxicity. To date, three selective CDK4/6 inhibitors have received approval from the U.S. Food and Drug Administration (FDA), and 15 CDK4/6 inhibitors are in clinical trials for the treatment of cancers. In this perspective, we discuss the crucial roles of CDK4/6 in regulating the cell cycle and cancer cells, analyze the rationale for selectively inhibiting CDK4/6 for cancer treatment, review the latest advances in highly selective CDK4/6 inhibitors with different chemical scaffolds, explain the mechanisms associated with CDK4/6 inhibitor resistance and describe solutions to overcome this issue, and briefly introduce proteolysis targeting chimera (PROTAC), a new and revolutionary technique used to degrade CDK4/6.

Disturbed Yin-Yang balance: stress increases the susceptibility to primary and recurrent infections of herpes simplex virus type 1

Herpes simplex virus type 1 (HSV-1), a neurotropic herpes virus, is able to establish a lifelong latent infection in the human host. Following primary replication in mucosal epithelial cells, the virus can enter sensory neurons innervating peripheral tissues nerve termini. The viral genome is then transported to the nucleus where it can be maintained without producing infectious progeny, and thus latency is established in the cell. Yin-Yang balance is an essential concept in traditional Chinese medicine (TCM) theory. Yin represents stable and inhibitory factors, and Yang represents the active and aggressive factors. When the organism is exposed to stress, especially psychological stress caused by emotional stimulation, the Yin-Yang balance is disturbed and the virus can re-engage in productive replication, resulting in recurrent diseases. Therefore, a better understanding of the stress-induced susceptibility to HSV-1 primary infection and reactivation is needed and will provide helpful insights into the effective control and treatment of HSV-1. Here we reviewed the recent advances in the studies of HSV-1 susceptibility, latency and reactivation. We included mechanisms involved in primary infection and the regulation of latency and described how stress-induced changes increase the susceptibility to primary and recurrent infections.

Rociletinib (CO-1686) enhanced the efficacy of chemotherapeutic agents in ABCG2-overexpressing cancer cells and o

Overexpression of adenosine triphosphate (ATP)-binding cassette subfamily G member 2 (ABCG2) in cancer cells is known to cause multidrug resistance (MDR), which severely limits the clinical efficacy of chemotherapy. Currently, there is no FDA-approved MDR modulator for clinical use. In this study, rociletinib (CO-1686), a mutant-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), was found to significantly improve the efficacy of ABCG2 substrate chemotherapeutic agents in the transporter-overexpressing cancer cells and in MDR tumor xenografts in nude mice, without incurring additional toxicity. Mechanistic studies revealed that in ABCG2-overexpressing cancer cells, rociletinib inhibited ABCG2-mediated drug efflux and increased intracellular accumulation of ABCG2 probe substrates. Moreover, rociletinib, inhibited the ATPase activity, and competed with [I] iodoarylazidoprazosin (IAAP) photolabeling of ABCG2. However, ABCG2 expression at mRNA and protein levels was not altered in the ABCG2-overexpressing cells after treatment with rociletinib. In addition, rociletinib did not inhibit EGFR downstream signaling and phosphorylation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK). Our results collectively showed that rociletinib reversed ABCG2-mediated MDR by inhibiting ABCG2 efflux function, thus increasing the cellular accumulation of the transporter substrate anticancer drugs. The findings advocated the combination use of rociletinib and other chemotherapeutic drugs in cancer patients with ABCG2-overexpressing MDR tumors.

RICTOR/mTORC2 affects tumorigenesis and therapeutic efficacy of mTOR inhibitors in esophageal squamous cell carcinoma

Dysregulation of mTORC1/mTORC2 pathway is observed in many cancers and mTORC1 inhibitors have been used clinically in many tumor types; however, the mechanism of mTORC2 in tumorigenesis is still obscure. Here, we mainly explored the potential role of mTORC2 in esophageal squamous cell carcinoma (ESCC) and its effects on the sensitivity of cells to mTOR inhibitors. We demonstrated that RICTOR, the key factor of mTORC2, and p-AKT (Ser473) were excessively activated in ESCC and their overexpression is related to lymph node metastasis and the tumor-node-metastasis (TNM) phase of ESCC patients. Furthermore, we found that mTORC1/ mTORC2 inhibitor PP242 exhibited more efficacious anti-proliferative effect on ESCC cells than mTORC1 inhibitor RAD001 due to RAD001-triggered feedback activation of AKT signal. Another, we demonstrated that down-regulating expression of RICTOR in ECa109 and EC9706 cells inhibited proliferation and migration as well as induced cell cycle arrest and apoptosis. Noteworthy, knocking-down stably RICTOR significantly suppresses RAD001-induced feedback activation of AKT/PRAS40 signaling, and enhances inhibition efficacy of PP242 on the phosphorylation of AKT and PRAS40, thus potentiates the antitumor effect of RAD001 and PP242 both and . Our findings highlight that selective targeting mTORC2 could be a promising therapeutic strategy for future treatment of ESCC.

Small molecules for fat combustion: targeting obesity

Obesity is increasing in an alarming rate worldwide, which causes higher risks of some diseases, such as type 2 diabetes, cardiovascular diseases, and cancer. Current therapeutic approaches, either pancreatic lipase inhibitors or appetite suppressors, are generally of limited effectiveness. Brown adipose tissue (BAT) and beige cells dissipate fatty acids as heat to maintain body temperature, termed non-shivering thermogenesis; the activity and mass of BAT and beige cells are negatively correlated with overweight and obesity. The existence of BAT and beige cells in human adults provides an effective weight reduction therapy, a process likely to be amenable to pharmacological intervention. Herein, we combed through the physiology of thermogenesis and the role of BAT and beige cells in combating with obesity. We summarized the thermogenic regulators identified in the past decades, targeting G protein-coupled receptors, transient receptor potential channels, nuclear receptors and miscellaneous pathways. Advances in clinical trials were also presented. The main purpose of this review is to provide a comprehensive and up-to-date knowledge from the biological importance of thermogenesis in energy homeostasis to the representative thermogenic regulators for treating obesity. Thermogenic regulators might have a large potential for further investigations to be developed as lead compounds in fighting obesity.

Correlations between the p-Akt-mTOR-p70S6K pathway and clinicopathological features or chemoresistance of ovarian cancer / 中南大学学报(医学版)

Objective:To study the relationship between alpha seine/threonine-protein kinase (p-Akt)-serine/ threonine-protein kinase (mTOR)-ribosomal protein S6 kinase (p70S6K) signaling pathway and clinicopathological features or chemoresistance of ovarian cancer.Methods:We checked the p-Akt,mTOR and p70S6K protein levels in 18 tissues with chemoresistance or 25 with chemosensitivity of ovarian cancer by immunohistochemistry technique,and analyzed the relationship between those proteins and clinicopathological features or chemoresistance of ovarian cancer.Results:The levels of p-Akt protein in ovarian serous carcinoma,mucinous carcinoma and endometrioid carcinoma were 77.14%,50.00% and 66.67%,respectively,with no significant difference (P>0.05).The levels of these proteins in well-middle differentiated carcinoma and low differentiated carcinoma were 73.33% and 75.00%,respectively,with no significant difference (P>0.05).The levels of these proteins in Ⅰ-Ⅱ stage carcinoma,and Ⅲ-Ⅳ stage carcinoma were 18.18% and 93.75%,respectively,with significant difference (P0.05).The levels of this protein in well-middle differentiated carcinoma and low differentiated carcinoma were 80.00% and 78.57%,respectively,with no significant difference (P>0.05).The levels of this protein in Ⅰ-Ⅱ stage carcinoma,and Ⅲ-Ⅳ stage carcinoma were 27.27% and 96.88%,respectively,with significant difference (P0.05).The levels of this protein in well-middle differentiated carcinoma and low differentiated carcinoma were 93.33% and 78.57%,respectively,with no significant difference (P>0.05).The levels of this protein in Ⅰ-Ⅱ stage carcinoma,and Ⅲ-Ⅳ stage carcinoma were 45.45% and 96.88%,respectively,with significant difference (P<0.05).The levels of p-Akt protein in tissue of chemoresistance and chemosensitivity of ovarian cancer were 88.89% and 64.00%,respectively,with significant difference (P<0.05).The levels of mTOR protein in tissue of chemoresistance and chemosensitivity of ovarian cancer were 94.44% and 68.00%,respectively,with significant difference (P<0.05).The levels of p70S6K protein in tissue of chemoresistance and chemosensitivity of ovarian cancer were 100.00% and 72.00%,respectively,with significant difference (P<0.05).Conclusion:The p-Akt-mTOR-p70S6K signaling pathway may take part in invasion and metastasis of ovarian cancer.The up-regulation of these proteins may be associated with the chemoresistance of ovarian cancer,and these proteins may have potential to be the prognostic markers for the chemoresistance of ovarian cancer.

Effects of erythropoietin on apoptosis and expression of AKT in rats of chronic heart failure / 天津医药

Objective To investigate the effects of erythropoietin (EPO) on myocardial apoptosis and protein kinase B (AKT) expression in rats of chronic heart failure (CHF). Methods Thirty male adult SD rats were randomly divided into two groups, sham-operated (Sham) group (n=6) and model (Model) group (n=24). The abdominal aortic coarctation was used to build CHF model. Sixteen survived rats after operation were randomly divided into two groups including EPO group and con-trol (Control) group. EPO group was received 3 000 U/kg EPO intraperitoneal injection 3 times/week for 4 weeks, and Sham group and Control group were received same volume of normal saline. The echocardiography was used to evaluate cardiac function after 4 weeks, 8 weeks and 12 weeks of treatment. After 12 weeks, all rats were sacrificed after 24 h fasting. The cell morphology and myocardial apoptosis were observed, and apoptosis index (AI) was calculated. Myocardial P-AKT/AKT pro-tein expression was detected by Western blot assay. Results Echocardiography showed that ventricular hypertrophy was found in model group after four weeks, heart failure 8 weeks. Compared with Control group, left ventricular ejection fraction (LVEF) was significantly higher after EPO intervention for 4 weeks (P < 0.05), systolic interventricular septum thickness (IVSs), end-systolic left ventricular posterior wall thickness (LVPWs), diastolic interventricular septum thickness (IVSd), af-ter left ventricular end-diastolic wall thickness (LVPWd) were significantly lower (P<0.05). The value of AI was significant-ly lower in EPO group than that of Control group (23.87%±1.45%vs 35.58%±2.81%, P<0.01). The OD value of P-AKT/AKT was significantly decreased in Control group (0.35±0.06) than that of Sham group (0.81±0.17), the value was significant-ly increased in EPO group (1.61±0.16) than that of Control group (P<0.01). Conclusion EPO can improve heart function, inhibit myocardial apoptosis,and promote pro-phosphorylation of AKT in rats with chronic heart failure.

Silent mating-type information regulator 2 homolog 1 (SIRT1) in Alzheimer’ s disease:an update on potential mechanisms / 中国药理学通报

Alzheimer ’ s disease ( AD ) is characterized by pro-gressive loss of memory and other cognitive functions .With re-cent discoveries , activation of silent mating-type information reg-ulator 2 homolog 1 ( SIRT1 ) could attenuate the cognitive dys-function of AD via reducing amyloid-βaggregation and tau pro-tein phosphorylation , inhibiting inflammatory reaction , and regu-lating synaptic plasticity .This review aims to highlight the in-volvement of these new discoveries of SIRT 1, and Akt/protein kinase B(PKB) signaling pathways, for their potential therapeu-tic effect against AD .

HIF-1α pathway: role, regulation and intervention for cancer therapy

Hypoxia-inducible factor-1 (HIF-1) has been recognized as an important cancer drug target. Many recent studies have provided convincing evidences of strong correlation between elevated levels of HIF-1 and tumor metastasis, angiogenesis, poor patient prognosis as well as tumor resistance therapy. It was found that hypoxia (low O2 levels) is a common character in many types of solid tumors. As an adaptive response to hypoxic stress, hypoxic tumor cells activate several survival pathways to carry out their essential biological processes in different ways compared with normal cells. Recent advances in cancer biology at the cellular and molecular levels highlighted the HIF-1α pathway as a crucial survival pathway for which novel strategies of cancer therapy could be developed. However, targeting the HIF-1α pathway has been a challenging but promising progresses have been made in the past twenty years. This review summarizes the role and regulation of the HIF-1α in cancer, and recent therapeutic approaches targeting this important pathway.

Bile acid signaling and biliary functions

This review focuses on various components of bile acid signaling in relation to cholangiocytes. Their roles as targets for potential therapies for cholangiopathies are also explored. While many factors are involved in these complex signaling pathways, this review emphasizes the roles of transmembrane G protein coupled receptor (TGR5), farnesoid X receptor (FXR), ursodeoxycholic acid (UDCA) and the bicarbonate umbrella. Following a general background on cholangiocytes and bile acids, we will expand the review and include sections that are most recently known (within 5-7 years) regarding the field of bile acid signaling and cholangiocyte function. These findings all demonstrate that bile acids influence biliary functions which can, in turn, regulate the cholangiocyte response during pathological events.

Role of farnesoid X receptor and bile acids in alcoholic liver disease

Alcoholic liver disease (ALD) is one of the major causes of liver morbidity and mortality worldwide. Chronic alcohol consumption leads to development of liver pathogenesis encompassing steatosis, inflammation, fibrosis, cirrhosis, and in extreme cases, hepatocellular carcinoma. Moreover, ALD may also associate with cholestasis. Emerging evidence now suggests that farnesoid X receptor (FXR) and bile acids also play important roles in ALD. In this review, we discuss the effects of alcohol consumption on FXR, bile acids and gut microbiome as well as their impacts on ALD. Moreover, we summarize the findings on FXR, FoxO3a (forkhead box-containing protein class O3a) and PPARα (peroxisome proliferator-activated receptor alpha) in regulation of autophagy-related gene transcription program and liver injury in response to alcohol exposure.

Effect of calreticulin gene silencing on proliferation and invaison in human hepatocellular carcinoma cells / 中华肝胆外科杂志

Objective To explore the effect of calreticulin (CRT) on cell proliferation and invasion of human hepatocellular carcinoma cell line SMMC-7721 and HepG2.Methods SMMC-7721 and HepG2 cells were transfected with small interfering RNA (siRNA).The transfection rate was detected by immunoflurescence and western blot.The cell proliferation,invasion and apoptosis of SMMC-7721 and HepG2 cells were determined by using cell counting kit-8 (CCK-8) assays,transwell assays and flow cytometry,respectively.The p-Akt and Akt levels were detected by western blot.Results The growth inhibition rate in the siRNA experimental group of SMMC-7721 and HepG2 cells for 24,36 and 48 h were (41.0 ±2.2) ％,(46.5 ±1.6)％,(59.7 ±2.2)％ and (36.8 ±2.7)％,(47.3 ± 1.8)％,(61.5 ±3.2)％,respectively.The apoptosis rate after down-regulating the expression of CRT in SMMC-7721 and HepG2 cells for 36h were (45.2 ± 9.1) ％ and (48.9 ± 8.0) ％,respectively.Compared with the blank group and the negative control group,the growth inhibition rate in the siRNA experimental group was lower (P ＜0.05),but the apoptosis rate was significantly higher (P ＜ 0.05).Transwell experiments confirmed that the numbers of invaded SMMC-7721 and HepG2 cells in the blank group and the negative control group and siRNA experimental group were (96.8±7.3),(95.6±5.4),(34.0±4.2) and (124.0 ±9.9),(121.6 ±7.0),(70.4±9.5),respectively,indicating that cell invasion in the siRNA experimental group was significantly suppressed (P ＜ 0.05).The expression of p-Akt was decreased (P ＜ 0.05) after down-regulating the expression of CRT for 36h.Conclusion CRT gene silencing by siRNA can inhibit the SMMC-7721 and HepG2 cell proliferation and invasion,but increase the cell apoptosis by regulating PI3K/Akt signal pathway.

Activation of Akt/protein kinase B mediates the protective effects of mechanical stretching against myocardial ischemia-reperfusion injury

Akt/protein kinase B is a well-known cell survival factor and activated by many stimuli including mechanical stretching. Therefore, we evaluated the cardioprotective effect of a brief mechanical stretching of rat hearts and determined whether activation of Akt through phosphatidylinositol 3-kinase (PI3K) is involved in stretch-induced cardioprotection (SIC). Stretch preconditioning reduced infarct size and improved post-ischemic cardiac function compared to the control group. Phosphorylation of Akt and its downstream substrate, GSK-3beta, was increased by mechanical stretching and completely blocked by wortmannin, a PI3K inhibitor. Treatment with lithium or SB216763 (GSK-3beta inhibitors) before ischemia induction mimicked the protective effects of SIC on rat heart. Gadolinium (Gd3+), a blocker of stretch-activated ion channels (SACs), inhibited the stretch-induced phosphorylation of Akt and GSK-3beta. Furthermore, SIC was abrogated by wortmannin and Gd3+. In vivo stretching induced by an aorto-caval shunt increased Akt phosphorylation and reduced myocardial infarction; these effects were diminished by wortmannin and Gd3+ pretreatment. Our results showed that mechanical stretching can provide cardioprotection against ischemia-reperfusion injury. Additionally, the activation of Akt, which might be regulated by SACs and the PI3K pathway, plays an important role in SIC.

Amyloid β-protein fragment 25-35 down-regulates PI3K/Akt /p70S6K pathway in rat hippocampus in vivo / 中国药理学与毒理学杂志

AIM To investigate whether Aβ deposit in Alzheimer disease(AD) impairs signal transduction pathway responsible for neuronal survival.METHODSThe rats were randomly divided into six groups:control group and Aβ25-35 group,Aβ25-35+ibuprofen groups (7.5 and 15 mg·kg-1,respectively),Aβ25-35+ibuprofen+LY294002 group,and Aβ25-35+LY294002 group.Rats were given ibuprofen (7.5 and 15 mg·kg-1 daily,ig) for 3 weeks prior to and 1 week after icv single dose of Aβ25-35 (10 μL,1 mmol·L-1).LY294002 was injected icv 1 h before the injection of Aβ25-35.Seven days after Aβ25-35 injection,the hippocampal expressions of P53,Bax,Fas ligand (FasL),Bcl-2 proteins,phospho-Akt/PKB,and phosphorylated 70 ku ribosomal protein S6 kinase (p70S6K) and caspase 3 were determined in the brain tissue preparations from CA1 area with Western blot.The activity of caspase 3 was measured using a caspase 3 colorimetric activity assay kit.RT-PCR was used to show the change of p70s6k mRNA level.RESULTS Aβ25-35 icv injection significantly down-regulated phosphorylated Akt/PKB from 1.32±0.14 to 0.69±0.08 and p70S6K from 0.769±0.028 to 0.479±0.032 in hippocampal CA1 region.These changes were accompanied by increased expressions of the proapoptotic proteins P53,Bax,and FasL and decreased expression of the anti-apoptotic protein Bcl-2 in rat hippocampus.In addition,caspase 3 activity was significantly enhanced in hippocampal CA1 region in Aβ25-35-treated rats compared with control rats.Ibuprofen can reverse these Aβ25-35-induced changes.CONCLUSION Down-regulated anti-apoptotic PI3K/Akt/p70S6K signaling pathway induced by Aβ25-35 in rat hippocampus may contribute to the neuronal damage in AD.Ibuprofen prevents Aβ25-35-induced down-regulation of PI3K/Akt/p70S6K signaling pathway.

Angiotensin n induces apoptosis in tubular epithelial cells through inhibiting the phospho-rylation of serine-threonine kinase Akt/protein kinase B / 中华肾脏病杂志

Objective To investigate whether the signaling pathway of PI3K-AKT is involved in Ang II-induced apoptosis in rat renal tubular epithelial cells (NRK-52E).Methods Cultured cells were incubated in media containing either buffer (control) or different concentrations of Ang II (10-9 to 10-6 mol/L) for 24 h. Cells were stained by Annexin V-F1TC/PI Kit and apoptosis was evaluated by flow cytometer. Western blotting was performed to assess the levels of PI3K, total- and phosphor-AKT. Results Ang II induced tubular epithelial cell apoplosis in a dose dependent manner. Ang II significantly inhibited the phosphorylation of AKT. The level of AKT phosphorylation was negatively correlated with apoptosis in Ang II-stimulated cells(r=-0.90 ,P