The effect of celastrol in combination with 5-fluorouracil on proliferation and apoptosis of gastric cancer cell lines

Background:Despite the availability of chemotherapy drugs such as 5-fluorouracil(5-FU),the treatment of some cancers such as gastric cancer remains challenging due to drug resistance and side effects.This study aimed to investigate the effect of celastrol in combination with the chemotherapy drug 5-FU on proliferation and induction of apoptosis in human gastric cancer cell lines(AGS and EPG85-257).Materials and Methods:In this in vitro study,AGS and EPG85-257 cells were treated with different concentrations of celastrol,5-FU,and their combination.Cell proliferation was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT)assay.The synergistic effect of 5-FU and celastrol was studied using Compusyn software.The DNA content at different phases of the cell cycle and apoptosis rate was measured usingflow cytometry.Results:Co-treatment with low concentrations(10%inhibitory concentration(IC10))of celastrol and 5-FU significantly reduced IC50(p<0.05)so that 48 h after treatment,IC50 was calculated at 3.77 and 6.9μM for celastrol,20.7 and 11.6μM for 5-FU,and 5.03 and 4.57μM for their combination for AGS and EPG85-257 cells,respectively.The mean percentage of apoptosis for AGS cells treated with celastrol,5-FU,and their combination was obtained 23.9,41.2,and 61.9,and for EPG85-257 cells 5.65,46.9,and 55.7,respectively.In addition,the 5-FU and celastrol-5-FU combination induced cell cycle arrest in the synthesis phase.Conclusions:Although celastrol could decrease the concentration of 5-fluorouracil that sufficed to suppress gastric cancer cells,additional studies are required to arrive at conclusive evidence on the anticancer effects of celastrol.

Construction of chlorogenic acid-containing liposomes with prolonged antitumor immunity based on T cell regulation

As a potential cancer immunotherapeutic agent,chlorogenic acid(CHA)has entered phase II clinical trials in China as a lyophilized powder formulation for treating glioma.However,the in vivo instability of CHA necessitates daily intramuscular injections,resulting in patient noncompliance.In this study,CHA-phospholipid complex(PC)-containing PEGylated liposomes(CHA-PC PEG-Lipo,named as CPPL),with CHA-PC as the drug intermediate,were prepared to lower the administration frequency.CPPL demonstrated excellent physicochemical properties,enhanced tumor accumulation,and inhibited tumor growth even when the administration interval was prolonged to 4 days when compared to a CHA solution and CHA-PC loaded liposomes(CHA-PC Lipo,labeled as CPL),both of which only demonstrated antitumor efficacy with once-daily administration.Further evaluation of the in vivo antitumor immune mechanism suggested that the extended antitumor immune efficacy of CPPL could be attributed to its distinct immune-stimulating mechanism when compared with CHA solution and CPL,such as stimulating both CD4+and CD8+T cell infiltration,inhibiting myeloid-derived suppressor cell expression,reducing the expression of Th2 related factors,and notably,increasing the memory T cells in tumor tissues.This CHA-containing formulation could reduce the frequency of in vivo CHA administration during cancer treatment via T cells,especially memory T cell regulation.

Cell cycle regulation and anticancer drug discovery

Cellular growth,development,and differentiation are tightly controlled by a conserved biological mechanism:the cell cycle.This cycle is primarily regulated by cyclin-dependent kinase(CDK)-cyclin complexes,checkpoint kinases,and CDK inhibitors.Deregulation of the cell cycle is a hallmark of the transformation of normal cells into tumor cells.Given its importance in tumorigenesis,several cell cycle inhibitors have emerged as potential therapeutic drugs for the treatment of cancers-both as singleagent therapy and in combination with traditional cytotoxic or molecular targeting agents.In this review,we discuss the mechanisms underlying cell cycle regulation and present small-molecule anticancer drugs that are under development,including both pan-CDK inhibitors and CDK4/6-selective inhibitors.In addition,we provide an outline of some promising CDK inhibitors currently in preclinical and clinical trials that target cell cycle abnormalities in various cancers.

Research Progress in the Regulation of Tumor Cells and Tumor Stem Cells at Multiple Targets by Antrodia camphorata

Extensive in vitro and in vivo research reveals multiple intracellular molecular targets of Antrodia camphorata,and these targets affect growth,apoptosis,angiogenesis,invasion and metastasis of cells.These targets include tumor suppressor,cell cycle regulator,transcription factor,angiogenesis and metastasis factor,apoptosis and survival regulator,etc.Additionally,more and more attention has been paid to the molecular mechanism of A.camphorata on the regulation of tumor stem cells.Meanwhile,there is evidence that the immunoregulation of A.camphorata is enhanced,which may lead cell cycle arrest or apoptosis.In this paper,molecular mechanism of tumor cells and tumor stem cells regulated at multiple targets by A.camphorata in vitro and in vivo in the past decade is summarized.

Small regulators making big impacts:regulation of neural stem cells by small non-coding RNAs

Neurodegeneration and traumatic brain injuries are leading causes of disability and present an enormous disease burden both in terms of patient suffering and healthcare cost.Treatment of brain lesions remains as a major challenge in medicine largely because of the limited regenerative capacity of the adult brain.

Viral infections and cell cycle G2/M regulation

Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast (Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15 (Tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. These Cdc2 regulators are the downstream targets of two well- characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins, which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest. Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small T antigen, polyomavirus T antigen, HTLV Tax and adenovirus E4orf4. Thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

Regulation of neuroinflammatory properties of glial cells by T cell effector molecules

Multiple sclerosis （MS） is a chronic inflammatory and neurodegenerative disorder that is thought to be mediated by autoreactive T lymphocytes that find their way into the central nervous system （CNS）. The pathological mechanism of MS is still being elucidated but it involves complex interactions between infiltrating immune cells and resi- dent glial cells within the CNS that culminate into strong neuroinflammation and axonal damage.

Genetic polymorphisms in genes regulating cell death and prognosis of patients with rectal cancer receiving postoperative chemoradiotherapy

Objective:The identification of biomarkers for predicting chemoradiotherapy efficacy is essential to optimize personalized treatment.This study determined the effects of genetic variations in genes involved in apoptosis,pyroptosis,and ferroptosis on the prognosis of patients with locally advanced rectal cancer receiving postoperative chemoradiotherapy(CRT).Methods:The Sequenom MassARRAY was used to detect 217 genetic variations in 40 genes from 300 patients with rectal cancer who received postoperative CRT.The associations between genetic variations and overall survival(OS)were evaluated using hazard ratios(HRs)and 95%confidence intervals(CIs)computed using a Cox proportional regression model.Functional experiments were performed to determine the functions of the arachidonate 5-lipoxygenase(ALOX5)gene and the ALOX5 rs702365 variant.Results:We detected 16 genetic polymorphisms in CASP3,CASP7,TRAILR2,GSDME,CASP4,HO-1,ALOX5,GPX4,and NRF2 that were significantly associated with OS in the additive model(P<0.05).There was a substantial cumulative effect of three genetic polymorphisms(CASP4 rs571407,ALOX5 rs2242332,and HO-1 rs17883419)on OS.Genetic variations in the CASP4 and ALOX5 gene haplotypes were associated with a higher OS.We demonstrated,for the first time,that rs702365[G]>[C]represses ALOX5 transcription and corollary experiments suggested that ALOX5 may promote colon cancer cell growth by mediating an inflammatory response.Conclusions:Polymorphisms in genes regulating cell death may play essential roles in the prognosis of patients with rectal cancer who are treated with postoperative CRT and may serve as potential genetic biomarkers for individualized treatment.

Regulation of neural stem cell fate decisions by mitochondrial dynamics

Stem cells possess the ability to divide symmetrically or asymmet- rically to allow for maintenance of the stem cell pool or become committed progenitors and differentiate into various cell lineages. The unique self-renewal capabilities and pluripotency of stem cells are integral to tissue regeneration and repair （Oh et al., 2014）. Mul- tiple mechanisms including intracellular programs and extrinsic cues are reported to regulate neural stem cell （NSC） fate （Bond et al., 2015）. A recent study, published in Cell Stern Cell, identified a novel mechanism whereby mitochondrial dynamics drive NSC fate （Khacho et al., 2016）.

DIFFERENCES IN EXPRESSION AND REGULATION BETWEEN TRANSFORMED CELLS OF THE HUMAN GASTRIC CARCINOMA ONCOGENE Ha-ras AND THE UNTRANSFORMED PARENT CELLS

An Ha-ras oncogene was isolated from a cell line of gastric carcinoma called BGE-823 in order to elucidate genetic control and the influence of DNA sequences. The oncogene was cloned and identified as a single nucleotide substitution of thymine for guanine in the 12th codon through the sequencing of its first axon. We compared the differences of expression and regulation between the transformed Ha-ras cells and untransformed parent cells. Data indicated that the expression of Ha-ras in the transformed cells was five-fold higher than in the untransformed cells and that the Ha-ras gene in the former was hypersensitive toward DNase I. In addition, a nuclear protein of 35 kilodaltons bound strongly to the 2.5 Kb fragment located upstream of the 6.6 Kb Ha-ras gene and contained a CC rich region. These results suggest that there might be another mechanism of activation for the ras gene besides point mutation.

Regulation of neural stem/progenitor cell functions by P2X and P2Y receptors

Neural stem/progenitor cells：Radial glial cells constitute multipotent cells in the ventricular zone,lining the wall of the lateral ventricle of the embryonic brain.They have the capacity to give rise to cells belonging to all three major linages（neurons,astrocytes and oligodendrocytes）of the nervous system（Tang and Illes,2017）.

Ferroptosis mechanism and Alzheimer's disease

Regulated cell death is a genetically determined form of programmed cell death that commonly occurs during the development of living organisms.This process plays a crucial role in modulating homeostasis and is evolutionarily conserved across a diverse range of living organisms.Ferroptosis is a classic regulatory mode of cell death.Extensive studies of regulatory cell death in Alzheimer’s disease have yielded increasing evidence that fe rroptosis is closely related to the occurrence,development,and prognosis of Alzheimer’s disease.This review summarizes the molecular mechanisms of ferroptosis and recent research advances in the role of ferro ptosis in Alzheimer’s disease.Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for Alzheimer’s disease.

JAK/STAT signaling regulates tissue outgrowth and male germline stem cell fate in Drosophila

In multicellular organisms, biological activities are regulated by cell signaling. The various signal transduction path- ways regulate cell fate, proliferation, migration, and polarity. Miscoordination of the communicative signals will lead to disasters like cancer and other fatal diseases. The JAK/STAT signal transduction pathway is one of the pathways, which was first identified in vertebrates and is highly conserved throughout evolution. Studying the JAK/STAT signal transduc- tion pathway in Drosophila provides an excellent opportunity to understand the molecular mechanism of the cell regu- lation during development and tumor formation. In this review, we discuss the general overview of JAK/STAT signaling in Drosophila with respect to its functions in the eye development and stem cell fate determination.

Do pyroptosis, apoptosis, and necroptosis (PANoptosis) exist in cerebral ischemia? Evidence from cell and rodent studies

Some scholars have recently developed the concept of PANoptosis in the study of infectious diseases where pyroptosis,apoptosis and necroptosis act in consort in a multimeric protein complex,PANoptosome.This allows all the components of PANoptosis to be regulated simultaneously.PANoptosis provides a new way to study the regulation of cell death,in that different types of cell death may be regulated at the same time.To test whether PANoptosis exists in diseases other than infectious diseases,we chose cerebral ischemia/reperfusion injury as the research model,collected articles researching cerebral ischemia/reperfusion from three major databases,obtained the original research data from these articles by bibliometrics,data mining and other methods,then integrated and analyzed these data.We selected papers that investigated at least two of the components of PANoptosis to check its occurrence in ischemia/reperfusion.In the cell model simulating ischemic brain injury,pyroptosis,apoptosis and necroptosis occur together and this phenomenon exists widely in different passage cell lines or primary neurons.Pyroptosis,apoptosis and necroptosis also occurred in rat and mouse models of ischemia/reperfusion injury.This confirms that PANoptosis is observed in ischemic brain injury and indicates that PANoptosis can be a target in the regulation of various central nervous system diseases.

RANKL signaling in bone marrow mesenchymal stem cells negatively regulates osteoblastic bone formation

RANKL signaling is essential for osteoclastogenesis. Its role in osteoblastic differentiation and bone formation is unknown. Here we demonstrate that RANK is expressed at an early stage of bone marrow mesenchymal stem cells(BMSCs) during osteogenic differentiation in both mice and human and decreased rapidly. RANKL signaling inhibits osteogenesis by promoting β-catenin degradation and inhibiting its synthesis. In contrast, RANKL signaling has no significant effects on adipogenesis of BMSCs.Interestingly, conditional knockout of rank in BMSCs with Prx1-Cre mice leads to a higher bone mass and increased trabecular bone formation independent of osteoclasts. In addition, rank: Prx1-Cre mice show resistance to ovariectomy-(OVX) induced bone loss. Thus, our results reveal that RANKL signaling regulates both osteoclasts and osteoblasts by inhibition of osteogenic differentiation of BMSCs and promotion of osteoclastogenesis.

Effects of virus infection on expression of cell cycle regulatory proteins in the unicellular marine algae Emiliania huxleyi

The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G 2 /M-phase regulatory proteins are analyzed by immunobloting in unicel-lular Emiliania huxleyi,suggesting that virus induced cell cycle arrest is related with virus＇s effect on cyclins and cyclin dependent kinases. E. huxleyi virus（EhV） represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner,blocking host cells G 2 /M checkpoint. Dephosphorylated /inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors,which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication.

Transcriptomic analysis reveals putative osmoregulation mechanisms in the kidney of euryhaline turbot Scophthalmus maximus responded to hypo-saline seawater

Turbot harbor a relatively remarkable ability to adapt to opposing osmotic challenges and are an excellent model species to study the physiological adaptations of flounder associated with osmoregulatory plasticity.The kidney transcriptome of turbot treated 24 h in water of hypo-salinity(salinity 5)and seawater(salinity 30)was sequenced and characterized.In silico analysis indicated that all unigenes had significant hits in seven databases.The functional annotation analysis of the transcriptome showed that the immune system and biological processes associated with digestion,absorption,and metabolism played an important role in the osmoregulation of turbot in response to hypo-salinity.Analysis of biological processes associated with inorganic channels and transporters indicated that mineral absorption and bile secretion contributed to iono-osmoregulation resulting in cell volume regulation and cell phenotypic plasticity.Moreover,we analyzed and predicted the mechanisms of canonical signaling transduction.Biological processes involved in renin secretion,ECM-receptor interaction,adherens junction,and focal adhesion played an important role in the plasticity phenotype in hypo-stress,while the signal transduction network composed of the MAPK signaling pathway and PI3K-Akt signaling pathway with GABAergic synapse,worked in hypoosmoregulation signal transduction in the turbot.In addition,analysis of the tissue specificity of targeted gene expression using qPCR during salinity stress was carried out.The results showed that the kidney,gill,and spleen were vital regulating organs of osmotic pressure,and the osmoregulation pattern of euryhaline fish dif fered among species.

SHP2 regulates skeletal cell fate by modifying SOX9 expression and transcriptional activity

Chondrocytes and osteoblasts differentiate from a common mesenchymal precursor, the osteochondroprogenitor（OCP）, and help build the vertebrate skeleton. The signaling pathways that control lineage commitment for OCPs are incompletely understood. We asked whether the ubiquitously expressed protein-tyrosine phosphatase SHP2（encoded by Ptpn11） affects skeletal lineage commitment by conditionally deleting Ptpn11 in mouse limb and head mesenchyme using ＂Cre-lox P＂-mediated gene excision.SHP2-deficient mice have increased cartilage mass and deficient ossification, suggesting that SHP2-deficient OCPs become chondrocytes and not osteoblasts. Consistent with these observations, the expression of the master chondrogenic transcription factor SOX9 and its target genes Acan, Col2a1, and Col10a1 were increased in SHP2-deficient chondrocytes, as revealed by gene expression arrays, q RT-PCR, in situ hybridization, and immunostaining. Mechanistic studies demonstrate that SHP2 regulates OCP fate determination via the phosphorylation and SUMOylation of SOX9, mediated at least in part via the PKA signaling pathway. Our data indicate that SHP2 is critical for skeletal cell lineage differentiation and could thus be a pharmacologic target for bone and cartilage regeneration.

Alpl prevents bone ageing sensitivity by specifically regulating senescence and differentiation in mesenchymal stem cells

Mutations in the liver/bone/kidney alkaline phosphatase(Alpl) gene cause hypophosphatasia(HPP) and early-onset bone dysplasia,suggesting that this gene is a key factor in human bone development. However, how and where Alpl acts in bone ageing is largely unknown. Here, we determined that ablation of Alpl induces prototypical premature bone ageing characteristics, including bone mass loss and marrow fat gain coupled with elevated expression of p16INK4A(p16) and p53 due to senescence and impaired differentiation in mesenchymal stem cells(MSCs). Mechanistically, Alpl deficiency in MSCs enhances ATP release and reduces ATP hydrolysis. Then, the excessive extracellular ATP is, in turn, internalized by MSCs and causes an elevation in the intracellular ATP level, which consequently inactivates the AMPKα pathway and contributes to the cell fate switch of MSCs. Reactivating AMPKα by metformin treatment successfully prevents premature bone ageing in Alpl+/-mice by improving the function of endogenous MSCs.These results identify a previously unknown role of Alpl in the regulation of ATP-mediated AMPKα alterations that maintain MSC stemness and prevent bone ageing and show that metformin offers a potential therapeutic option.

Fluid and Osmotic Pressure Balance and Volume Stabilization in Cells Dedicated to Professor Karl Stark Pister for his 95th birthday

A fundamental problem for cells with their fragile membranes is the control of their volume.The primordial solution to this problem is the active transport of ions across the cell membrane to modulate the intracellular osmotic pressure.In this work,a theoretical model of the cellular pump-leak mechanism is proposed within the general framework of linear nonequilibrium thermodynamics.The model is expressed with phenomenological equations that describe passive and active ionic transport across cell membranes,supplemented by an equation for the membrane potential that accounts for the electrogenicity of the ionic pumps.For active ionic transport,the model predicts that the intracellular fluid pressure will be balanced by the osmotic pressure and a new pressure component that arises from the active ionic fluxes.A model for the pump-leak mechanism in an idealized human cell is introduced to demonstrate the applicability of the proposed theory.