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PubMed1993

Comparative effects of aging process on phosphatidylcholine biosynthesis pathway: a key role for CTP-phosphocholine cytidylyltransferase?

The effects of aging on phosphatidylcholine (PtdCho) biosynthesis were investigated in liver and brain subcellular fractions of the rat, by studying the activity and regulation of CTP phosphocholine cytidylyltransferase (CT), the rate limiting enzyme in PtdCho biosyntheses. With both tissues, CT activity was present in cytosolic and microsomal fractions, but in brain, CT activity seemed to escape to an inhibiting feed back mechanism. In brain, CT activity was greater in the microsomal fraction, whilst in liver, a higher CT activity was seen in the cytosolic fraction. In liver fractions of aged animals, there was no significant change in CT activity or its sensitivity to negative feedback regulation, as compared to young animals. In contrast, a progressive age related decline in CT activity was observed in the brain microsomal fraction. Furthermore, the incorporation of newly formed CDPCho into PtdCho was also reduced in aged animals, and paralleled the decreased incorporation of choline in PtdCho. The age-related decrease in CT activity cannot be explained by product feed back inhibition or decreased diacylglycerol levels. Since PtdCho is a major membrane lipid, the reduction in CT activity may lead to a decreased membrane integrity and fluidity during the aging process, and these effects may be greater in neuronal cells.

Aging↗

PubMed1999

The mitogen-activated protein kinase kinase/extracellular signal-regulated kinase cascade activation is a key signalling pathway involved in the regulation of G(1) phase progression in proliferating hepatocytes.

In this study, activation of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signalling pathway was analyzed in proliferating rat hepatocytes both in vivo after partial hepatectomy and in vitro following epidermal growth factor (EGF)-pyruvate stimulation. First, a biphasic MEK/ERK activation was evidenced in G(1) phase of hepatocytes from regenerating liver but not from sham-operated control animals. One occurred in early G(1) (30 min to 4 h), and the other occurred in mid-late G(1), peaking at around 10.5 h. Interestingly, the mid-late G(1) activation peak was located just before cyclin D1 induction in both in vivo and in vitro models. Second, the biological role of the MEK/ERK cascade activation in hepatocyte progression through the G(1)/S transition was assessed by adding a MEK inhibitor (PD 98059) to EGF-pyruvate-stimulated hepatocytes in primary culture. In the presence of MEK inhibitor, cyclin D1 mRNA accumulation was inhibited, DNA replication was totally abolished, and the MEK1 isoform was preferentially targeted by this inhibition. This effect was dose dependent and completely reversed by removing the MEK inhibitor. Furthermore, transient transfection of hepatocytes with activated MEK1 construct resulted in increased cyclin D1 mRNA accumulation. Third, a correlation between the mid-late G(1) MEK/ERK activation in hepatocytes in vivo after partial hepatectomy and the mitogen-independent proliferation capacity of these cells in vitro was established. Among hepatocytes isolated either 5, 7, 9, 12 or 15 h after partial hepatectomy, only those isolated from 12- and 15-h regenerating livers were able to replicate DNA without additional growth stimulation in vitro. In addition, PD 98059 intravenous administration in vivo, before MEK activation, was able to inhibit DNA replication in hepatocytes from regenerating livers. Taken together, these results show that (i) early induction of the MEK/ERK cascade is restricted to hepatocytes from hepatectomized animals, allowing an early distinction of primed hepatocytes from those returning to quiescence, and (ii) mid-late G(1) MEK/ERK activation is mainly associated with cyclin D1 accumulation which leads to mitogen-independent progression of hepatocytes to S phase. These results allow us to point to a growth factor dependency in mid-late G(1) phase of proliferating hepatocytes in vivo as observed in vitro in proliferating hepatocytes and argue for a crucial role of the MEK/ERK cascade signalling pathway.

Animals↗

PubMed1989

Gas chromatographic and gas chromatographic/tandem mass spectrometric characterization of precursors on the sesterterpene pathway for steroid biosynthesis.

An increasing amount of evidence is accumulating to support the proposal that steroidogenesis can occur by a sesterterpene pathway as well as the cholesterol pathway. Key intermediates on the sesterterpene pathway are 23,24-dinor-5-cholen-3 beta-ol (guneribol) and some of its metabolites, e.g. 23,24-dinor-4-cholen-3-one (guneribone). It has been reported that these intermediates are biosynthesized and converted to steroid hormones by a range of endocrine tissues in vitro. Monitoring the pentafluorobenzyloxime derivatives by negative ion chemical ionization mass spectrometry in the electron capture mode provided evidence for the presence of guneribone in extracts of bovine testicular and human adrenal tumour tissue. Complementary evidence was obtained from gas chromatographic/tandem mass spectrometric data generated on a triple-quadrupole instrument by monitoring daughter ions (in the multiple ion detection, MID mode) of the molecular anion of derivatized guneribone in both standards and tissue extracts. The present findings that sesterterpene pathway intermediates are present as endogenous compounds in tissue extracts, together with the previously reported radiochemical data, give further support to the sesterterpene pathway hypothesis.

Adrenal Gland Neoplasms↗

PubMed1999

A temperature-dependent switch from chaperone to protease in a widely conserved heat shock protein.

Misfolding or unfolding of polypeptides can occur as a consequence of environmental stress and spontaneous mutation. The abundance of general chaperones and proteases suggests that cells distinguish between proteins that can be refolded and "hopeless" cases fated to enter the proteolytic pathway. The mechanisms controlling this key metabolic decision are not well understood. We show here that the widely conserved heat shock protein DegP (HtrA) has both general molecular chaperone and proteolytic activities. The chaperone function dominates at low temperatures, while the proteolytic activity is present at elevated temperatures. These results show that a single cellular factor can switch between two key pathways, controlling protein stability and turnover. Implications of this finding for intracellular protein metabolism are discussed.

Amylases↗

PubMed2000

Interactive health communication in preventive medicine: internet-based strategies in teaching and research.

Interactive health communication using Internet technologies is expanding the range and flexibility of intervention and teaching options available in preventive medicine and the health sciences. Advantages of interactive health communication include the enhanced convenience, novelty, and appeal of computer-mediated communication; its flexibility and interactivity; and automated processing. We outline some of these fundamental aspects of computer-mediated communication as it applies to preventive medicine. Further, a number of key pathways of information technology evolution are creating new opportunities for the delivery of professional education in preventive medicine and other health domains, as well as for delivering automated, self-instructional health behavior-change programs through the Internet. We briefly describe several of these key evolutionary pathways. We describe some examples from work we have done in Australia. These demonstrate how we have creatively responded to the challenges of these new "information environments," and how they may be pursued in the education of preventive medicine and other health care practitioners and in the development and delivery of health behavior-change programs through the Internet. Innovative and thoughtful applications of this new technology can increase the consistency, reliability, and quality of information delivered.

Australia↗

PubMed1989

Cloning and expression of the gene cluster encoding key proteins involved in acetyl-CoA synthesis in Clostridium thermoaceticum: CO dehydrogenase, the corrinoid/Fe-S protein, and methyltransferase.

Acetogenic bacteria fix CO or CO2 by a pathway of autotrophic growth called the acetyl-CoA (or Wood) pathway. Key enzymes in the pathway are a methyltransferase, a corrinoid/Fe-S protein, a disulfide reductase, and a carbon monoxide dehydrogenase. This manuscript describes the isolation of the genes that code for the methyltransferase, the two subunits of the corrinoid/Fe-S protein, and the two subunits of carbon monoxide dehydrogenase. These five genes were found to be clustered within an approximately 10-kilobase segment on the Clostridium thermoaceticum genome. The proteins were expressed at up to 5-10% of Escherichia coli cell protein, and isopropyl beta-D-thiogalactopyranoside had no effect on the levels of expression, implying that the C. thermoaceticum inserts contained transcriptional and translational signals that were recognized by E. coli. The methyltransferase is expressed in E. coli in a fully active dimeric form with a specific activity and heat stability similar to the enzyme expressed in C. thermoaceticum. However, both the corrinoid/Fe-S protein and carbon dioxide dehydrogenase, although expressed in high amounts and with identical subunit molecular weights in E. coli, are inactive and less heat stable than are the native enzymes from C. thermoaceticum.

Acetyl Coenzyme A↗

PubMed2000

Reversible phosphorylation at the C-terminal regulatory domain of p21(Waf1/Cip1) modulates proliferating cell nuclear antigen binding.

The p53-inducible gene product p21(WAF1/CIP1) plays a critical role in regulating the rate of tumor incidence, and identifying mechanisms of its post-translational regulation will define key pathways that link growth control to p21-dependent tumor suppression. A eukaryotic cell model system has been developed to determine whether protein kinase signaling pathways that phosphorylate human p21 exist in vivo and whether such pathways regulate the binding of p21 to one of its key target proteins, proliferating cell nuclear antigen (PCNA). Although human p21 expressed in Sf9 cells is able to form a complex with human PCNA, the inclusion of cell-permeable phosphatase inhibitors renders p21 protein inactive for PCNA binding. The treatment of this inactive isoform of p21 with alkaline phosphatase restores its binding to PCNA, suggesting that p21 expressed in Sf9 cells is subject to reversible phosphorylation at a key regulatory site(s). A biochemical approach was subsequently used to map the phosphorylation sites within p21, whose modification in vitro can inhibit p21-PCNA complex formation, to the C-terminal domain at residues Thr(145) or Ser(146). A phospho-specific antibody was developed that only bound to full-length p21 protein after phosphorylation in vitro at Ser(146), and this reagent was further used to demonstrate that the inactive isoform of p21 recovered from Sf9 cells treated with phosphatase inhibitors had been phosphorylated in vivo at Ser(146). These data identify the first phosphorylation site within the C-terminal regulatory domain of p21 whose modification in vivo modulates p21-PCNA interactions and define a eukaryotic cell model that can be used to study post-translational signaling pathways that regulate p21.

Amino Acid Sequence↗

PubMed2025

MEIS1 knockdown upregulates WNT signaling pathway genes in esophageal squamous cell carcinoma.

BACKGROUND: The transcription factor MEIS1 belongs to the 3-amino acid loop extension (TALE) family of homeodomain proteins which plays various functions in normal and tumor cell progression. The canonical WNT/β-catenin pathway governs a plethora of biological processes including cell proliferation, differentiation, and tumor development. In the present study, the effect of MEIS1 gene silencing was assessed on WNT pathway genes in esophageal squamous cell carcinoma (ESCC) cells. MATERIALS AND METHODS: Along with the packaging plasmids, the pLKO.1-MEIS1 plasmid was cotransfected into HEK293T to generate lentiviral particles, followed by transduction of a semi-confluent KYSE-30 cell culture. After total RNA extraction and cDNA synthesis, comparative real-time PCR was applied to assess the efficiency of MEIS1 knockdown and the expression of genes related to the WNT signaling pathway. RESULTS: The results revealed effective downregulation of MEIS1 in KYSE-30 cells. Interestingly, MEIS1 silencing led to a substantial overexpression of WNT pathway key components while the expression of negative regulators of this pathway was substantially decreased. CONCLUSIONS: Our data suggest that MEIS1 gene probably induces WNT/β-catenin pathway deactivation in ESCC cells. Consequently, the inverse correlation of MEIS1 expression and WNT signaling pathway activation may introduce a new molecular linkage through ESCC progression and aggressiveness.

Humans↗

PubMed1998

Stress-activated signalling pathways in yeast.

Eukaryotic cells have developed response mechanisms to combat the harmful effects of a variety of stress conditions. In the majority of cases, such responses involve changes in the gene expression pattern of the cell, leading to increased levels and activities of proteins that have stress-protective functions. Over the last few years, considerable progress has been made in understanding how stress-dependent transcriptional changes are brought about, and it transpires that the underlying mechanisms are highly conserved, being similar in organisms ranging from yeast to man. Many of the stress signals derive from the extracellular environment and accordingly these signals require transduction from the cell surface to the nucleus. This is accomplished through stress-activated signalling pathways, key amongst which are the highly conserved stress-activated MAP kinase pathways. Stimulation of these pathways leads to the increased activity of specific transcription factors and consequently the increased expression of certain stress-related genes. In this review, we focus on the progress that has been made in understanding these stress responses in yeast.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1996

Tumor suppression and apoptosis of human prostate carcinoma mediated by a genetic locus within human chromosome 10pter-q11.

Prostate cancer is the second leading cause of male cancer deaths in the United States. Yet, despite a large international effort, little is known about the molecular mechanisms that underlie this devastating disease. Prostate secretory epithelial cells and androgen-dependent prostate carcinomas undergo apoptosis in response to androgen deprivation and, furthermore, most prostate carcinomas become androgen independent and refractory to further therapeutic manipulations during disease progression. Definition of the genetic events that trigger apoptosis in the prostate could provide important insights into critical pathways in normal development as well as elucidate the perturbations of those key pathways in neoplastic transformation. We report the functional definition of a novel genetic locus within human chromosome 10pter-q11 that mediates both in vivo tumor suppression and in vitro apoptosis of prostatic adenocarcinoma cells. A defined fragment of human chromosome 10 was transferred via microcell fusion into a prostate adenocarcinoma cell line. Microcell hybrids containing only the region 10pter-q11 were suppressed for tumorigenicity following injection of microcell hybrids into nude mice. Furthermore, the complemented hybrids undergo programmed cell death in vitro via a mechanism that does not require nuclear localization of p53. These data functionally define a novel genetic locus, designated PAC1, for prostate adenocarcinoma 1, involved in tumor suppression of human prostate carcinoma and furthermore strongly suggest that the cell death pathway can be functionally restored in prostatic adenocarcinoma.

Adenocarcinoma↗

PubMed2026

Exploring the Potential Molecular Targets of Cyanidin-3-O-glucoside for Type 2 Diabetes Mellitus Treatment.

INTRODUCTION: This study aims to elucidate the multi-target molecular mechanism of cyanidin-3-O-glucoside (C3G) in treating Type 2 Diabetes (T2DM) through network pharmacology methods. METHODS: The study was designed to predict the targets of C3G through public databases and to screen for T2DM-related targets. Protein-protein interaction (PPI) network analysis, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on the common targets. Core targets were further validated through molecular docking and molecular dynamics (MD) simulations. RESULTS: This research identified a total of 57 potential targets of C3G in the treatment of T2DM. Subsequent PPI analysis identified ALB (Degree=43), AKT1 (Degree=41), and TNF (Degree=41) as the top three hub proteins. Pathway analysis indicated significant involvement in the insulin signaling pathway (P = 4.205×10-9), AMPK signaling pathway (P = 9.582×10-7), and FoxO signaling pathway (P = 1.315×10-6). Molecular docking revealed strong binding affinities between C3G and NOS3 (-9.5 kcal/mol), PPARG (-9.0 kcal/mol), TNF (-8.5 kcal/mol), and INSR (-8.4 kcal/mol). MD simulations further confirmed that the C3G-target complex has excellent binding stability. DISCUSSION: C3G may intervene in the pathological progression of T2DM by regulating key pathways such as insulin sensitivity, inflammatory responses, and oxidative stress. Further studies suggest that INSR and NOS3 may be new targets through which C3G exerts its effects, but their specific mechanisms and in vivo biological functions still need to be elucidated by subsequent experiments. CONCLUSION: C3G may intervene in the progression of T2DM in a multi-pathway synergistic manner by targeting key molecules such as INSR and NOS3.

Anthocyanins↗

PubMed2026

TMEM33 regulates the proliferation and migration of lung adenocarcinoma by promoting the PI3K/AKT/mTOR signaling pathway.

Lung adenocarcinoma is a common type of lung cancer with high incidence and mortality rates. TMEM33, a tumor-associated protein, has not been fully elucidated in lung adenocarcinoma. To explore the expression of TMEM33 in lung adenocarcinoma, its impact on tumor progression, and its role in the PI3K/AKT/mTOR signaling pathway. Key genes associated with lung adenocarcinoma were screened using the Gene Expression Omnibus (GEO) dataset GSE140797 in combination with a weighted correlation network analysis (WGCNA). Gene Ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed on these key genes. TMEM33 expression in Lung adenocarcinoma patients was validated using data from the TCGA database. The directly interactive molecules were screened through a bioinformatics method. Cellular assays (Western Blot, CCK8, colony formation, scratch assay, Trans well assay) and a nude mouse model were used to investigate the effects of TMEM33 on cell proliferation, migration, and tumor growth. TMEM33 is highly expressed in lung adenocarcinoma tissues (P < 0.05) and associated with poor prognosis. Overexpression of TMEM33 promotes cell proliferation and migration, and activates the PI3K/AKT/mTOR signaling pathway (P < 0.01). In the nude mouse model, TMEM33 overexpression increases tumor volume (P < 0.001), and PI3K/AKT pathway inhibition suppresses these effects (P < 0.05, P < 0.01). TMEM33 acts as an oncogene in lung adenocarcinoma by activating the PI3K/AKT/mTOR pathway, providing new therapeutic targets.

Cell migration↗

PubMed2025

Impact of Maternal Aspirin Therapy on Neonatal Epigenetic Patterns.

BACKGROUND: Low-dose aspirin (LDA) is an intervention recommended to prevent the development of hypertensive disorders of pregnancy (HDP) in high-risk pregnancies. Maternal conditions such as HDP have been associated with cord blood epigenetic changes including those related to cardiovascular processes; however, it is unclear whether maternal aspirin therapy may impact neonatal epigenetics in otherwise healthy high-risk pregnancy. OBJECTIVE: This study aimed to determine if maternal LDA exposure in utero leads to altered DNA methylation in umbilical cord blood cells in term neonates compared with controls not exposed to aspirin, and to identify if these methylation changes alter key pathways in the development of chronic disease. METHODS: Umbilical cord blood was collected from 10 neonates without LDA exposure and 13 neonates with LDA exposure in utero. Patients with hypertensive disorders of pregnancy, COVID-19, and chorioamnionitis were excluded. Genomic DNA was isolated from umbilical cord blood cells and genome-wide DNA methylation was performed using Illumina Methylation EPIC assay. RESULTS: A total of 155 differentially methylated loci (81 genes were hypermethylated and 74 were hypomethylated) were identified in LDA-exposed neonatal umbilical cord blood compared with the control group. Important canonical pathways identified by Ingenuity Pathway Analysis (IPA) were related to Th1 and Th2 signaling and classical (M1) macrophage activation. The genes affected by LDA exposure were associated with cardiac and renal systems. CONCLUSION: LDA exposure led to differential DNA methylation in umbilical cord blood. The differentially methylated genes were related to inflammatory pathways as well as cardiac and renal toxicity pathways. LDA exposure in utero may promote altered health programming in the neonate in areas impacting cardiovascular health. KEY POINTS: · Maternal aspirin exposure is associated with differential DNA methylation in cord blood.. · Cord blood epigenetic changes associated with maternal aspirin relate to anti-inflammatory pathways.. · Research on potential protective impact of maternal aspirin on neonatal epigenetics is warranted..

Humans↗

PubMed2026

Desmoplakin loss in alveolar epithelium drives Wnt/β-Catenin-mediated extracellular matrix remodeling and fibrotic signaling in vitro.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic interstitial lung disease characterized by aberrant extracellular matrix (ECM) remodeling, epithelial dysfunction, and limited therapeutic options. Genetic studies implicate Desmoplakin (DSP), a desmosomal adhesion protein, in IPF susceptibility; however, its mechanistic role remains unclear. This study aimed to investigate the role of DSP in regulating fibrotic and ECM remodeling pathways in alveolar epithelial cells. METHODS AND RESULTS: DSP was silenced using siRNA in adenocarcinoma-derived human alveolar epithelial A549 cells. DSP loss induced epithelial-to-mesenchymal transition, enhanced cell migration, and increased epithelial permeability, along with upregulation of fibrotic and ECM-associated genes. Pathway enrichment analysis of DSP interactors (STRING database) identified the Wnt/β-catenin signaling as a potential key pathway. Mechanistic validation using cycloheximide chase assays, qPCR, western blotting, immunofluorescence, and luciferase-reporter assays suggested that DSP loss destabilizes desmosomal complexes, promoting plakoglobin (γ-catenin) degradation while reducing β-catenin turnover. This was associated with increased nuclear accumulation of β-catenin and enhanced TCF/LEF-dependent transcription, leading to elevated expression of ECM-related genes, including COL1A1 and MMP9. DSP overexpression suppressed Wnt/β-catenin signaling and fibrotic gene expression, while pharmacological inhibition of this pathway attenuated DSP-dependent increases in ECM-associated gene expression. CONCLUSION: These findings suggest that DSP may function as a regulator of alveolar epithelial homeostasis and extracellular matrix remodeling in an in vitro epithelial model. Loss of DSP is associated with activation of Wnt/β-catenin-mediated fibrotic signaling, correlating with reduced plakoglobin stability. This study provides mechanistic insight into epithelial-matrix crosstalk in vitro and identifies a candidate pathway that may contribute to ECM dysregulation in IPF, the disease relevance of which will require validation in primary human alveolar epithelial cells and in vivo models.

Humans↗

PubMed2026

MYDGF as a telomerase activator and therapeutic target for osteoarthritis.

Osteoarthritis (OA) involves progressive cartilage breakdown. This is driven by impaired chondrocyte function and an imbalance in the extracellular matrix homeostasis. However, the key upstream regulators that maintain healthy chondrocytes are still not fully known. Here, we report that myeloid-derived growth factor (MYDGF) is a novel regulator of telomerase activity and is critical for cartilage health. Using a genome-wide CRISPR-Cas9 screen with a TERT reporter system, MYDGF was identified as a strong positive regulator of telomerase. Functional studies confirmed that MYDGF positively regulates TERT expression and telomerase activity in both HeLa and ATDC5 cells. In a mouse surgical destabilization of the medial meniscus (DMM) OA model, MYDGF knockout (KO) mice exhibited more severe cartilage damage. Conversely, delivering MYDGF into the knee joint using AAV virus partially alleviated cartilage injury. Transcriptome profiling revealed that MYDGF-deficient chondrocytes exhibit downregulated key pathways involved in matrix building and upregulated inflammatory signals, indicating a shift in cell state. In summary, our work establishes MYDGF as a key upstream factor for both telomerase and cartilage matrix homeostasis remodeling. It connects telomerase function to chondrocyte health. These findings also highlight MYDGF as a promising new target for treating osteoarthritis.

Cartilage degeneration↗

PubMed2025

Four-dimensional data independent acquisition proteomics and metabolomics reveal mechanisms of hydrogen-rich water at Zusanli (ST36) point against triple-negative breast cancer in mice.

OBJECTIVE: To develop a safe and effective green therapy for triple-negative breast cancer, this study combines hydrogen-rich water with acupuncture point injection, and finds that it can prevent tumor growth and minimize cancer metastasis. METHODS: After 21 d of hydrogen rich water injection treatment on 4T1 (mouse breast cancer cells) xenograft mice, in order to systematically identify differentially expressed proteins in tumor samples between the model group and the Zusanli (ST36) group injected with hydrogen rich water at acupoints, with a focus on functional proteins or signaling pathways related to tumor occurrence and development, researchers conducted four-dimensional data independent acquisition (4D-DIA) proteomic analysis on tumor tissues. In order to further investigate the dynamic changes of metabolites after therapeutic intervention, researchers conducted liquid chromatography-tandem mass spectrometry untargeted metabolomics identification and analysis on mouse serum. The results of the joint proteomics-metabolomics analysis were validated using experimental methods such as immunofluorescence, Western blotting, and quantitative reverse transcription polymerase chain reaction detection. RESULTS: Injecting hydrogen-rich water into acupoints significantly inhibited tumor growth (P < 0.05). 4D-DIA proteomics and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses uncovered pathways such as T helper 1 cell (Th1) and T helper 2 cell (Th2) cell differentiation. The KEGG metabolic pathways identified in the metabolomics analysis included galactose metabolism along with fructose and mannose metabolism. Based on the combined proteomics and metabolomics analysis, the key pathways included the C-type lectin receptor signaling pathway. The major cancer-related differential proteins detected in Th1 and Th2 cell differentiation [interleukin 6 signal transducer, nuclear factor of activated T cells 4, recombinant mitogen activated protein kinase 10 (MAPK10), and MAPK11] were upregulated after the injection of hydrogen-rich water into the Zusanli (ST36) acupoint, whereas Linker for activation of T cells (Lat), signal transducer and activator of transcription 1, and protein kinase C, theta were downregulated. CONCLUSION: The injection of hydrogen-rich water into the Zusanli (ST36) acupoint effectively inhibited the hyperplasia of 4T1 BC cells and enhanced their apoptosis, potentially exerting a therapeutic effect through multiple pathways and targeting various sites.

Animals↗

PubMed1997

New understanding of the pathogenesis of CML: a prototype of early neoplasia.

The 9;22 chromosomal translocation characteristic of CML results in a fused bcr/abl gene and an abnormal fusion protein, p210bcr/abl. Relative to normal c-abl, p210bc1/abl has elevated tyrosine kinase activity that is essential for its transforming activity. We recently reported a prominent 62 kDa GAP-associated P-tyr protein and five additional consistent but less prominent P-tyr proteins as well as five more minor P-tyr proteins that are constitutively tyrosine phosphorylated in primary primitive lineage negative (lin-) chronic phase CML blasts but not in comparable primary lin- normal blasts. The GAP-associated p62 protein has now been purified, sequenced and its gene has been cloned; it is a previously unidentified protein and is currently being characterized. In analyzing P-tyr proteins in primary lin- normal blasts in response to various hematopoietic cytokines, we found a striking similarity in the tyrosine phosphorylation of four major and three minor proteins after stimulation with c-kit ligand (KL) and the P-tyr proteins that are constitutively phosphorylated in primary primitive lin- chronic phase CML blasts. Other cytokines tested (ie GM-CSF, G-CSF, IL-3, FLT3 ligand, TPO, EPO) were much less active or stimulated phosphorylation of other proteins. KL/c-kit and bcr/abl have some similar activities including enhancing survival and expansion of hematopoietic progenitor cells, probably acting primarily on early progenitors at the time of lineage commitment rather than on self-renewing stem cells. Activation of growth factor receptors promote a cascade of protein phosphorylations that can ultimately result in a wide range of cellular responses. Sustained activation of discrete signaling pathways in some types of cells results in differentiation, whereas transient activation instead causes a proliferative response; in other cell types, the converse is true. It may be postulated that stem cells and primitive progenitors are at a particularly susceptible stage of development that renders them especially responsive to sustained bcr/abl-induced phorphorylation of a number of signaling proteins that are components of critical regulatory pathways, including c-kit. The affected pathways control and coordinate multiple diverse cell processes including proliferation, differentiation, maturation and apoptosis, processes that are normally tightly regulated and integrated. Perturbation of these key pathways in primitive progenitors would be expected to seriously disrupt orderly hematopoiesis and could also explain the multiple subtle pleiotropic biological abnormalities characteristically observed in later maturing CML compartments that we have collectively designated 'discordant maturation'. The true situation is undoubtedly very complex and involves interaction of multiple cytokines and signaling pathways that we are now trying to define. Constitutive downstream activation of critical pathways in susceptible early progenitors that normally require KL or other factors for activation could explain most if not all features of the disease.

Adolescent↗

PubMed1998

G-protein regulatory pathways: rocketing into the twenty-first century.

Complex cellular responses involve the integration of heterotrimeric G protein systems with protein kinase signal transduction pathways. Key in this integration is the control of small GTP-binding proteins including Ras and Rho family members. In this paper, we discuss the control of signal transduction pathways by G proteins and their integration with specific tyrosine kinases. The integration of G proteins, kinases, and small GTP-binding proteins in controlling cellular responses is illustrated through the newly defined G alpha 12/13-regulated pathways. Furthermore, the polymorphonuclear leukocyte provides a primary cell system for analyzing the integration of G proteins, kinases, and small GTP-binding proteins in controlling cellular functions such as superoxide production, adherence, chemotaxis, and granule secretion.

Animals↗