Complex roles of cAMP-PKA-CREB signaling in cancer

Natural products and ferroptosis: A novel approach for heart failure management

BACKGROUND

The discovery of ferroptosis has brought a revolutionary breakthrough in heart failure treatment, and natural products, as a significant source of drug discovery, are gradually demonstrating their extraordinary potential in regulating ferroptosis and alleviating heart failure symptoms. In addition to chemically synthesized small molecule compounds, natural products have attracted attention as an important source for discovering compounds that target ferroptosis in treating heart failure.

PURPOSE

Systematically summarize and analyze the research progress on improving heart failure through natural products' modulation of the ferroptosis pathway.

METHODS

By comprehensively searching authoritative databases like PubMed, Web of Science, and China National Knowledge Infrastructure with keywords such as "heart failure", "cardiovascular disease", "heart disease", "ferroptosis", "natural products", "active compounds", "traditional Chinese medicine formulas", "traditional Chinese medicine", and "acupuncture", we aim to systematically review the mechanism of ferroptosis and its link with heart failure. We also want to explore natural small-molecule compounds, traditional Chinese medicine formulas, and acupuncture therapies that can inhibit ferroptosis to improve heart failure.

RESULTS

In this review, we not only trace the evolution of the concept of ferroptosis and clearly distinguish it from other forms of cell death but also establish a comprehensive theoretical framework encompassing core mechanisms such as iron overload and system xc-/GSH/GPX4 imbalance, along with multiple auxiliary pathways. On this basis, we innovatively link ferroptosis with various types of heart failure, covering classic heart failure types and extending our research to pre-heart failure conditions such as arrhythmia and aortic aneurysm, providing new insights for early intervention in heart failure. Importantly, this article systematically integrates multiple strategies of natural products for interfering with ferroptosis, ranging from monomeric compounds and bioactive components to crude extracts and further to traditional Chinese medicine formulae. In addition, non-pharmacological means such as acupuncture are also included.

CONCLUSION

This study fills the gap in the systematic description of the relationship between ferroptosis and heart failure and the therapeutic strategies of natural products, aiming to provide patients with more diverse treatment options and promote the development of the heart failure treatment field.

Gastrodin prevents stress-induced synaptic plasticity impairment and behavioral dysfunction via cAMP/PKA/CREB signaling pathway

BACKGROUND

Chronic stress is widely recognized as a critical factor that impairs synaptic plasticity dependent brain function and behavior, contributing to the onset of depression and anxiety disorders, which subsequently undermine learning and memory processes. Gastrodin (GAS), a prominent bioactive constituent of Gastrodiae Rhizoma exhibiting notable neuroprotective properties, holds significant potential for the prevention and treatment of stress-induced neurological dysfunction. However, the protective effects of GAS on stress-induced synaptic plasticity impairment and the underlying mechanisms have yet to be fully elucidated.

OBJECTIVES

To investigate the potential of GAS in protecting synaptic plasticity from chronic stress and its underlying cellular and molecular mechanisms.

METHOD

A chronic stress model was constructed in C57BL/6J mice, and the effects of GAS on synaptic plasticity were examined using Golgi staining and immunohistochemistry. Systematic behavioral analysis was employed to assess the impact of GAS on depressive- and anxiety-like behaviors and cognitive function of mice. Metabolomics, transcriptomics, Western blotting, immunolocalization, enzyme-linked immunosorbent assay, and the administration of signal blockers were utilized to investigate the cellular and molecular pathways via which GAS safeguards synaptic plasticity.

RESULTS

The results showed that chronic stress exposure reduces the dendritic arbor complexity, density of dendritic spines, proportion of mushroom spines of hippocampal neurons, as well as disrupts synaptic function, impairs cognitive function and induces depressive-like behaviors. Importantly, impairment of hippocampal synaptic plasticity, anxiety- and depressive-like behaviors, and cognitive decline induced by chronic stress were significantly ameliorated following GAS treatment. Moreover, we identified the cAMP/PKA/CREB signaling in hippocampal neurons as a potential mechanism through which GAS prevents synaptic plasticity impairment from chronic stress exposure. Blockade of cAMP/PKA/CREB signaling abolished the protective effects of GAS on synaptic plasticity of hippocampal neurons and behaviors in stress-exposed mice.

CONCLUSION

This study is the first to identify GAS as a potential natural compound for alleviating stress-induced synaptic plasticity impairment and behavioral dysfunction by activating the cAMP/PKA/CREB signaling pathway in hippocampal neurons, offering a promising strategy for stress-induced neurological disorders.

miR-135b-5p/PDE3B Axis Regulates Gemcitabine Resistance in Pancreatic Cancer Through Epithelial-Mesenchymal Transition

Gemcitabine-based chemotherapy is an effective treatment for pancreatic cancer (PC), but gemcitabine resistance frequently compromises the therapeutic efficacy, resulting in clinical chemotherapeutic failure and a poor prognosis for patients. In this study, we investigated the mechanisms of gemcitabine chemoresistance in PC by examining the roles of microRNAs linked to gemcitabine resistance and their downstream signaling pathways. In vitro experiments were performed to alter miR-135b-5p levels in PC parental and drug-resistant cells to probe its function. miR-135b-5p targets PDE3B was confirmed by using RNA-seq technology to screen for gemcitabine-resistance-associated mRNAs in PC. A series of rescue experiments were performed after cotransfection, demonstrating that PDE3B could reverse miR-135b-5p-mediated chemoresistance and epithelial-mesenchymal transition (EMT). These findings indicate that the miR-135b-5p/PDE3B axis generates resistance by stimulating the EMT signaling pathway, which provides new insights into gemcitabine chemoresistance in PC.

Gpr109A in TAMs promoted hepatocellular carcinoma via increasing PKA/PPARγ/MerTK/IL-10/TGFβ induced M2c polarization

To delineate Gpr109A's role and mechanisms in modulating the immune microenvironment of hepatocellular carcinoma. Employing Gpr109A-knockout mice and in vitro co-cultures of hepatocellular carcinoma cells with macrophages, this study utilized a suite of techniques, including lentiviral vectors for stable cell line establishment, Western blotting, cell scratch, CCK-8, transwell assays, flow cytometry, immunohistochemistry and phagocytosis assay to assess various cellular behaviors and interactions. Gpr109A deletion markedly reduced the oncogenic potential of H22 cells, both in vivo and when co-cultured with knockout macrophages, impairing their growth, invasion, and migration. In Gpr109A-knockout macrophages, an upregulation of MerTK and a reduction in immunosuppressive cytokine release were observed, indicating a shift towards an M2c macrophage phenotype. This shift is linked to Gpr109A's role in promoting protease overexpression and inhibiting SHP2 phosphorylation, crucial for enhancing cancer cell proliferation and invasiveness. Gpr109A significantly influences macrophage polarization to the M2c type, augmenting hepatocellular carcinoma cell aggressiveness.

Targeting the bile acid receptor TGR5 with Gentiopicroside to activate Nrf2 antioxidant signaling and mitigate Parkinson's disease in an MPTP mouse model

INTRODUCTION

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by classical symptoms including bradykinesia, rest tremor and rigidity. Oxidative stress and mitochondrial dysfunction are recognized as pivotal factors in PD progression. Gentiopicroside (GPS), a secoiridoid derived from Gentiana manshurica Kitagawa, exhibits antioxidant and mitophagy induction properties. Nonetheless, the effects and mechanisms by which GPS mitigates neurodegeneration in PD remain to be thoroughly elucidated.

OBJECTIVES

The goal of this study was to investigate the neuroprotective effects and mechanisms of GPS in PD models.

METHODS

We established the MPTP/MPP+-induced PD models to measure the neuroprotection of GPS. Transcriptomic analysis, oxidative biochemical kits, western blot and cell immunofluorescence were conducted to elucidate the fundamental mechanisms at play. Subsequently, the targeting and activation of the transmembrane G protein-coupled receptor-5 (TGR5) by GPS were measured by molecular docking, cellular thermal shift assay, microscale thermophoresis (MST) and cyclic adenosine monophosphate (cAMP) quantitation. Finally, we verified whether the neuroprotective and antioxidant effects of GPS were dependent on TGR5 by using specific small interfering RNA (siRNA), pharmacological antagonist and knockout mice.

RESULTS

GPS significantly attenuated dopaminergic (DAergic) neuron loss and restored motor function in the MPTP-induced PD mouse model. Whole-genome RNA sequencing and subsequent mechanistic investigations revealed that GPS enhanced the expression and facilitated nuclear entry of factor erythroid-related 2-factor 2 (Nrf2), and reduced oxidative stress and mitochondrial dysfunction stimulated by neurotoxin. Additionally, GPS could target TGR5 and prevent its downregulation in PD model. TGR5's silencing or inhibition weakened the neuroprotective effect of GPS and blocked GPS-mediated activation of Nrf2 antioxidant signaling in PD model. Moreover, the therapeutic effect of GPS in mitigating motor deficits and neurodegeneration was also abolished in Tgr5 knockout mice.

CONCLUSION

These findings collectively indicated that GPS targeted TGR5 to activate Nrf2 antioxidant signaling and ultimately ameliorated the pathological progression of PD.

The Role of Scleral Changes in the Progression of Myopia: A Review and Future Directions

This review article comprehensively examines the alterations in scleral collagen fibers and the extracellular matrix (ECM) during myopia progression, with a particular focus on the scleral hypoxia theory and inflammatory mechanisms. It delves into key signaling pathways, including the matrix metalloproteinase - 2 (MMP-2) pathway, hypoxia - inducible factors (HIF-1α and HIF-2α) pathways, and the Wnt signaling pathway. By elucidating the intricate relationships between these signaling pathways, this article highlights the latest advancements in myopia prevention and control strategies that target the sclera. Moreover, it provides novel insights into the molecular mechanisms underlying scleral remodeling and explores their potential therapeutic applications for effectively managing myopia progression.

GALR1 and PENK serve as potential biomarkers in invasive non-functional pituitary neuroendocrine tumours

BACKGROUND

Some nonfunctioning pituitary neuroendocrine tumor (NFPitNET) can show invasive growth, which increases the difficulty of surgery and indicates a poor prognosis. However, the molecular mechanism related to invasiveness remains to be further studied. This study is to screen and identify the characteristic biomarkers of invasive NFPitNETs.

METHODS

Based on the data of 73 NFPitNETs microarray chips in the GSE169498 dataset, this study used weighted gene co-expression network (WGCNA), differential expression analysis, protein-protein interaction (PPI) network analysis and various machine learning methods (XGBOOST, LASSO regression, random forest, support vector machine) to screen candidate biomarkers for invasive NFPitNET. Then, using gene set enrichment analysis (GSEA) to explore the differences in biological activities and signaling pathways between invasive NFPitNET and non-invasive NFPitNET. Single-sample GSEA (ssGSEA) was used to analyze key biomarkers-related signaling pathways. Finally, the expression and function of the key biomarkers were verified by q-RT PCR, immunohistochemical (IHC) experiments and in vitro experiments.

RESULTS

Combined with WGCNA and differential expression analysis, 128 high-expression and 85 low-expression candidate biomarkers were preliminarily obtained. PPI analysis and four machine learning algorithms further identified GALR1, PENK and HOXD9. The receiver operating characteristic (ROC) curve results showed that the three biomarkers had good predictive ability of invasiveness. After combining the validation set data, GALR1 and PENK were the final key biomarkers. Finally, PCR and IHC results verified the decreased expression of GALR1 and PENK in invasive NFPitNET and promotes proliferation and invasive ablity of pituitary tumor cells.

CONCLUSION

This study confirmed that the reduced expression of GALR1 and PENK is an important molecular feature of invasive NFPitNETs, which may play an important role in inhibiting the development of NFPitNET.

Downregulation of CMIP contributes to preeclampsia development by impairing trophoblast function via the PDE7B-cAMP pathway

BACKGROUND

Preeclampsia (PE) is one of the leading causes of perinatal maternal and fetal morbidity and mortality, but its precise mechanism remains elusive. Previous research has suggested that c-Maf-inducible protein (CMIP) is abnormally expressed in PE pathophysiology. Therefore, we aimed to explore the potential role of CMIP and its downstream molecules in PE.

METHODS

Multiplex immunofluorescence and immunohistochemical assays were conducted on preeclamptic placentas. Functional analysis of CMIP was performed in HTR-8/SVneo cells through transfection experiments in which either CMIP was overexpressed or downregulated. RNA sequencing was utilized to identify the molecular pathways downstream of CMIP. The impact of hypoxia on CMIP levels was assessed in three different types of trophoblast cells. The therapeutic efficacy of CMIP was evaluated in an N(ω)-nitro-L-arginine methyl ester (L-NAME)-induced rat model of PE.

RESULTS

CMIP expression was downregulated in extrachorionic trophoblasts (EVTs) and syncytiotrophoblasts (STBs) in preeclamptic placentas. This downregulation of CMIP in trophoblast cells disrupts cell proliferation, migration, invasion, and angiogenesis by upregulating the PDE7B-cAMP pathway, while elevated CMIP levels enhance these cellular functions. Hypoxia reduced CMIP expression in all three types of trophoblast cells. Moreover, in a rat model of PE, supplementation with CMIP alleviated hypertension and increased fetal weight and number.

CONCLUSIONS

Our study demonstrates for the first time that the CMIP-PDE7B-cAMP pathway contributes to PE development by influencing trophoblast function. The signaling pathway proteins involved in PE induced by CMIP may provide new clues to the occurrence of PE and new targets for future PE therapy.

A transcriptomic and proteomic analysis and comparison of human brain tissue from patients with and without epilepsy

The present study was to investigate potential biomarkers and therapeutic targets for epilepsy by conducting a transcriptomic and proteomic analysis of human brain tissue from patients with epileptic lesions. Brain tissue was collected from the epileptic lesions after surgical resection and surgical removed brain tissue from non-epileptic patients. Using RNA sequencing and iTRAQ-based proteomic analysis, The transcriptomic analysis identified 1,604 DEGs, with 584 upregulated and 1,020 downregulated. The proteomic analysis identified 694 DEPs, with 331 upregulated and 363 downregulated. The combined transcriptomic and proteomic analysis showed that the DEGs and DEPs were mainly enriched in biological processes such as D-aspartate transport, transmembrane transport, cell junctions, vesicle transport, and metabolic processes. Tubulin polymerization promoting protein family member-3 (TPPP3), proprotein convertase subtilisin/kexin type-1 (PCSK1), and dihydropyrimidinase-like 3 (DPYSL3) were significantly altered in the epilepsy patients, and their expression trends were confirmed by the RT-qPCR, WB, and IHC staining results. By integrating transcriptomic and proteomic analyses, we identified genes and proteins expressed differently in epileptic and non-epileptic patients and their associated biological processes. Three key DEPs (TPPP3, PCSK1, and DPYSL3) were identified, indicating their potential significance in the pathological mechanisms of epilepsy.

GPR65 Inactivation in Tumor Cells Drives Antigen-Independent CAR T-cell Resistance via Macrophage Remodeling

SIGNIFICANCE

The study identifies GPR65 as an important determinant of B-cell acute lymphoblastic leukemia response to CAR T-cell therapy. Notably, GPR65 absence signals CAR T resistance. By emphasizing the therapeutic potential of targeting VEGFA or host macrophages, our study identifies routes to optimize CAR T-cell therapy outcomes in hematologic malignancies via tumor microenvironment manipulation.

PKA plays a conserved role in regulating gene expression and metabolic adaptation by phosphorylating Rpd3/HDAC1

Cells need to reprogram their metabolism to adapt to extracellular nutrient changes. The yeast histone acetyltransferase SAGA (Spt-Ada-Gcn5-acetyltransferase) has been reported to acetylate its subunit Ada3 and form homo-dimers to enhance its ability to acetylate nucleosomes and facilitate metabolic gene transcription. How cells transduce extracellular nutrient changes to SAGA structure and function changes remains unclear. Here, we found that SAGA is deacetylated by Rpd3L complex and uncover how its deacetylase activity is repressed by nutrient sensor protein kinase A (PKA). When sucrose is used as the sole carbon source, PKA catalytic subunit Tpk2 is activated, which phosphorylates Rpd3L catalytic subunit Rpd3 to inhibit its ability to deacetylate Ada3. Moreover, Tpk2 phosphorylates Rpd3L subunit Ash1, which specifically reduces the interaction between Rpd3L and SAGA. By phosphorylating both Rpd3 and Ash1, Tpk2 inhibits Rpd3L-mediated Ada3 deacetylation, which promotes SAGA dimerization, nucleosome acetylation and transcription of genes involved in sucrose utilization and tricarboxylate (TCA) cycle, resulting in metabolic shift from glycolysis to TCA cycle. Most importantly, PKA phosphorylates HDAC1, the Rpd3 homolog in mammals to repress its deacetylase activity, promote TCA cycle gene transcription and facilitate cell growth. Our work hence reveals a conserved role of PKA in regulating Rpd3/HDAC1 and metabolic adaptation.

Loss of DRD5P2 in hypoxia attenuates Rock2 degradation to promote EMT and gastric cancer metastasis

BACKGROUND

Metastasis is the leading cause of gastric cancer (GC)-related death. However, the molecular mechanisms underlying GC metastasis are not well understood. In this study, we focused on dopamine receptor 5 pseudogene 2 (DRD5P2), a novel long non-coding RNA, in GC metastasis.

METHODS

Expression of DRD5P2 in GC was detected by real-time PCR (RT-PCR) and fluorescence in situ hybridization (FISH). The effect of DRD5P2 in GC cells was examined by transwell invasion and migration assays. The pathways underlying DRD5P2/Rock2 signaling were studied by Western blot, co-immunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP) and RNA immunoprecipitation (RIP) analysis. Regulatory mechanism between hypoxia and DRD5P2 expression was explored in vitro by ChIP and Dual-luciferase reporter assays.

RESULTS

DRD5P2 expression is downregulated in advanced human GC and is associated with poor clinical outcomes. Gain- and loss-of-function studies showed that DRD5P2 inhibits GC cell migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro, as well as peritoneal dissemination in vivo. Mechanistic analysis revealed that DRD5P2 binds with Rock2 and recruits the E3 ubiquitin ligase KAP1 to mediate Rock2 degradation, thus suppressing the Ezrin/HRAS/ERK/CREB pathway and ultimately attenuating Snail-mediated EMT and GC metastasis. Furthermore, DRD5P2 transcription is inhibited by hypoxia in a HIF-1α/ZNF263-dependent manner in GC cells.

CONCLUSIONS

DRD5P2 acts as a tumor suppressor in GC metastasis by suppressing Rock2/ERK/Snail signaling, and DRD5P2 is transcriptionally suppressed under hypoxia via the HIF-1α/ZNF263 axis.

Redox Regulation of cAMP-Dependent Protein Kinase and Its Role in Health and Disease

Protein kinase A (PKA) is a key regulator of cellular signaling that regulates key physiological processes such as metabolism, cell proliferation, and neuronal function. While its activation by the second messenger 3',5'-cyclic adenosine triphosphate (cAMP) is well characterized, recent research highlights additional regulatory mechanisms, particularly oxidative post-translational modifications, that influence PKA's structure, activity, and substrate specificity. Both the regulatory and catalytic subunits of PKA are susceptible to redox modifications, which have been shown to play important roles in the regulation of key cellular functions, including cardiac contractility, lipid metabolism, and the immune response. Likewise, redox-dependent modulation of PKA signaling has been implicated in numerous diseases, including cardiovascular disorders, diabetes, and neurodegenerative conditions, making it a potential therapeutic target. However, the mechanisms of crosstalk between redox- and PKA-dependent signaling remain poorly understood. This review examines the structural and functional regulation of PKA, with a focus on redox-dependent modifications and their impact on PKA-dependent signaling. A deeper understanding of these mechanisms may provide new strategies for targeting oxidative stress in disease and restoring balanced PKA signaling in cells.

Mitochondrial, metabolic and bioenergetic adaptations drive plasticity of colorectal cancer cells and shape their chemosensitivity

The extent of mitochondrial heterogeneity and the presence of mitochondrial archetypes in cancer remain unknown. Mitochondria play a central role in the metabolic reprogramming that occurs in cancer cells. This process adjusts the activity of metabolic pathways to support growth, proliferation, and survival of cancer cells. Using a panel of colorectal cancer (CRC) cell lines, we revealed extensive differences in their mitochondrial composition, suggesting functional specialisation of these organelles. We differentiated bioenergetic and mitochondrial phenotypes, which point to different strategies used by CRC cells to maintain their sustainability. Moreover, the efficacy of various treatments targeting metabolic pathways was dependent on the respiration and glycolysis levels of cancer cells. Furthermore, we identified metabolites associated with both bioenergetic profiles and cell responses to treatments. The levels of these molecules can be used to predict the therapeutic efficacy of anti-cancer drugs and identify metabolic vulnerabilities of CRC. Our study indicates that the efficacy of CRC therapies is closely linked to mitochondrial status and cellular bioenergetics.

Integrated Analysis of the Anoikis-Related Signature Identifies Rac Family Small GTPase 3 as a Novel Tumor-Promoter Gene in Hepatocellular Carcinoma

Anoikis resistance in hepatocellular carcinoma (HCC) cells boosts survival and metastasis. This study aimed to establish an anoikis-related genes (ARGs)-based model for predicting HCC patients' outcomes and investigate the clinicopathological significance and function of crucial ARGs. The transcriptional expression patterns for HCC cohorts were compiled from TCGA, GEO and ICGC. Univariate and LASSO multivariate analyses were performed to screen for prognostic ARGs. Gain- and loss-of-function studies, RNA sequencing, and mass spectrometry were employed to elucidate the underlying mechanisms of ARGs in HCC. We established a five-gene ARGs risk model for HCC prognosis, with an AUC value of 0.812 for 1-year survival. Among the five genes, Rac family small GTPase 3 (RAC3) was upregulated in HCC relative to adjacent normal tissues and negatively correlated to overall survival and disease-free survival of patients with HCC. Silence of RAC3 in HCC cells resulted in an increased cell apoptosis and diminished cell proliferation and invasion. Mechanistically, we uncovered that RAC3 binding with SOX6 propelled the advancement of HCC cells through NNMT-mediated stimulation of the cAMP/MAPK/Rap1 signaling. In particular, EHop-016, a small molecule inhibitor targeting RAC3, significantly suppressed HCC progression.

A review of pharmacological mechanisms, challenges and prospects of macromolecular glycopeptides

Macromolecular glycopeptides are natural products derived from various sources, distinguished by their structural diversity, multifaceted biological activities, and low toxicity. These compounds exhibit a wide range of biological functions, such as immunomodulation, antitumor effects, anti-inflammatory properties, antioxidant activity, and more. However, limited understanding of natural glycopeptides has hindered their development and practical application. To promote their advancement and utilization, it is crucial to thoroughly investigate the pharmacological mechanisms of glycopeptides and address the challenges in natural glycopeptide research. This review uniquely focuses on the primary biological activities and potential molecular mechanisms of glycopeptides as reported in recent literature. Moreover, we emphasize the current challenges in glycopeptide research, including extraction and isolation difficulties, purification challenges, structural analysis complexities, elucidation of structure-activity relationships, characterization of biosynthetic pathways, and ensuring bioavailability and stability. The future prospects for glycopeptide research are also explored. We argue that ongoing research into glycopeptides will significantly contribute to drug development and provide more effective therapeutic options and disease treatment alternatives for human health.

cAMP response element-binding protein: A credible cancer drug target

Despite advancements in radiotherapy, chemotherapy, endocrine therapy, targeted therapy, and immunotherapy, resistance to therapy remains a pervasive challenge in oncology, in part owing to tumor heterogeneity. Identifying new therapeutic targets is key to addressing this challenge because it can both diversify and enhance existing treatment options, particularly through combination regimens. The cAMP response element-binding protein (CREB) is a transcription factor involved in various biological processes. It is aberrantly activated in several aggressive cancer types, including breast cancer. Clinically, high CREB expression is associated with increased breast tumor aggressiveness and poor prognosis. Functionally, CREB promotes breast cancer cell proliferation, survival, invasion, metastasis, as well as therapy resistance by deregulating genes related to apoptosis, cell cycle, and metabolism. Targeting CREB with small molecule inhibitors has demonstrated promise in preclinical studies. This review summarizes the current understanding of CREB mechanisms and their potential as a therapeutic target. SIGNIFICANCE STATEMENT: cAMP response element-binding protein (CREB) is a master regulator of multiple biological processes, including neurodevelopment, metabolic regulation, and immune response. CREB is a putative proto-oncogene in breast cancer that regulates the cell cycle, apoptosis, and cellular migration. Preclinical development of CREB-targeting small molecules is underway.

Thermogenesis and Energy Metabolism in Brown Adipose Tissue in Animals Experiencing Cold Stress

Cold exposure is a regulatory biological functions in animals. The interaction of thermogenesis and energy metabolism in brown adipose tissue (BAT) is important for metabolic regulation in cold stress. Brown adipocytes (BAs) produce uncoupling protein 1 (UCP1) in mitochondria, activating non-shivering thermogenesis (NST) by uncoupling fuel combustion from ATP production in response to cold stimuli. To elucidate the mechanisms underlying thermogenesis and energy metabolism in BAT under cold stress, we explored how cold exposure triggers the activation of BAT thermogenesis and regulates overall energy metabolism. First, we briefly outline the precursor composition and function of BA. Second, we explore the roles of the cAMP- protein kinase A (PKA) and adenosine monophosphate-activated protein kinase (AMPK) signaling pathways in thermogenesis and energy metabolism in BA during cold stress. Then, we analyze the mechanism by which BA regulates mitochondria homeostasis and energy balance during cold stress. This research reveals potential therapeutic targets, such as PKA, AMPK, UCP1 and PGC-1α, which can be used to develop innovative strategies for treating metabolic diseases. Furthermore, it provides theoretical support for optimizing cold stress response strategies, including the pharmacological activation of BAT and the genetic modulation of thermogenic pathways, to improve energy homeostasis in livestock.

Structural basis of human ABCC4 recognition of cAMP and ligand recognition flexibility

BACKGROUND

ABCC4 (ATP-binding cassette sub-family C member 4) is a transporter protein that is primarily localized to the plasma membrane, and its efflux activity is associated with the progression of various cancers and the development of drug resistance. Cyclic adenosine monophosphate (cAMP) is an important biomolecule that is considered a transport substrate of ABCC4. However, there is currently no direct structural understanding of how ABCC4 binds cAMP, and the mechanisms by which it recognizes a diverse range of substrate ligands remain poorly understood. Some studies have indicated that, under physiological conditions, cAMP does not significantly stimulate the ATPase activity of ABCC4, making the commonly used ATPase activity assays for ABC proteins unsuitable for studying cAMP.

RESULTS

Here, we successfully resolved the cryo-electron microscopy (cryo-EM) structure of the human ABCC4-cAMP (hABCC4-cAMP) complex, revealing how hABCC4 binds to cAMP and identifying the key residues involved. This structure was compared with two other hABCC4 complex structures we obtained (Methotrexate and Prostaglandin E2) and with previously published structures. We discovered some new structural insights into how hABCC4 binds ligands. On the basis of the structural information obtained, we confirmed the feasibility of using 8-[Fluo]-cAMP in a transport assay to detect cAMP translocation and found that some challenges remain to be addressed.

CONCLUSIONS

These results suggest that hABCC4 can bind cAMP and exhibits varying degrees of flexibility when binding with different substrates, including cAMP. These findings expand our understanding of the structural biology of ABCC4.

Glucagon-like peptide 1 receptor agonists and cancer risk: advancing precision medicine through mechanistic understanding and clinical evidence

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as a primary first-line treatment for type 2 diabetes. This has raised concerns about their impact on cancer risk, spurring extensive research. This review systematically examines the varied effects of GLP-1RAs on the risk of different types of tumors, including overall cancer risk and specific cancers such as thyroid, pancreatic, reproductive system, liver, and colorectal cancers. The potential biological mechanisms underlying their influence on cancer risk are complex, involving metabolic regulation, direct antitumor effects, immune modulation, and epigenetic changes. A systematic comparison with other antidiabetic agents reveals notable differences in their influence on cancer risk across drug classes. Additionally, critical factors that shape the relationship between GLP-1RAs and cancer risk are thoroughly analyzed, including patient demographics, comorbidities, treatment regimens, and lifestyle factors, offering essential insights for developing individualized treatment protocols. Despite significant research progress, critical gaps remain. Future research should prioritize elucidating the molecular mechanisms behind the antitumor effects, refining individualized treatment strategies, investigating early tumor prevention applications, assessing potential benefits for non-diabetic populations, advancing the development of novel therapies, establishing robust safety monitoring frameworks, and building precision medicine decision-making platforms. These efforts aim to establish novel roles for GLP-1RAs in cancer prevention. and treatment, thereby advancing the progress of precision medicine.

Intensive stress impedes hair follicle growth through triggering cell cycle arrest of hair follicle stem cells

The detrimental effects of stress on hair growth are supported by empirical and experimental evidence, but the specific impact and mechanisms remain poorly understood. Here we utilized two intensive stress paradigms, repeated resiniferatoxin (RTX) injections and physical restraint in mice, to assess the effects of intensive stress on hair follicle growth after depilation. Initially, macroscopic pictures of the mice dorsal skin and HE staining showed a substantial inhibition of depilation-induced hair growth in both telogen and anagen hair follicle growth under intensive stress induced by RTX and restraint. Mechanistically, single-cell RNA sequencing analysis of mice skin under intensive stress highlighted a significant downregulation of cell-cycle genes and upregulation of the cAMP signaling pathway in Lgr5+ hair follicle stem cells (HFSCs). Notably, the sympathetic nervous system was activated under intensive stress. Then, the neurotransmitter noradrenaline (NA), a secretion of the sympathetic nervous system, and 8-bromo-cAMP, a cAMP analog, were used to manifest the inhibitory effect of the sympathetic nervous system on HaCaT cell proliferation, as evidenced by the results of decreased cell activity and colony formation, downregulated expression of cyclin D1/2 and CDK4, the increased percentage of G0/G1, and decreased percentage of the S phase. Importantly, hair follicle regeneration was significantly inhibited by NA and 8-bromo-cAMP in mice. Collectively, our study suggests that intensive stress inhibits the cell cycle of hair follicle growth through the sympathetic nervous system/NA/cAMP pathway, thus providing a mechanistic insight into intensive stress-induced inhibition in hair follicle growth.

Cholesterol inhibits assembly and oncogenic activation of the EphA2 receptor

The receptor tyrosine kinase EphA2 drives cancer malignancy by facilitating metastasis. EphA2 can be found in different self-assembly states: as a monomer, dimer, and oligomer. However, we have a poor understanding regarding which EphA2 state is responsible for driving pro-metastatic signaling. To address this limitation, we have developed SiMPull-POP, a single-molecule method for accurate quantification of membrane protein self-assembly. Our experiments reveal that a reduction of plasma membrane cholesterol strongly promotes EphA2 self-assembly. Indeed, low cholesterol levels cause a similar effect to the EphA2 ligand ephrinA1-Fc. These results indicate that cholesterol inhibits EphA2 assembly. Phosphorylation studies in different cell lines reveal that low cholesterol increased phospho-serine levels in EphA2, the signature of oncogenic signaling. Investigation of the mechanism that cholesterol uses to inhibit the assembly and activity of EphA2 indicate an in-trans effect, where EphA2 is phosphorylated by protein kinase A downstream of beta-adrenergic receptor activity, which cholesterol also inhibits. Our study not only provides new mechanistic insights on EphA2 oncogenic function, but it also suggests that cholesterol acts as a molecular safeguard mechanism that prevents uncontrolled self-assembly and activation of EphA2.

Stress and Obesity Signaling Converge on CREB Phosphorylation to Promote Pancreatic Cancer

One of the deadliest types of cancer is pancreatic ductal adenocarcinoma (PDAC). Chronic stress and obesity are recognized as risk factors for PDAC. We hypothesized that the combination of stress and obesity strongly promotes pancreatic cancer development and growth. Here, we show that the stress mediator norepinephrine and the β-adrenergic receptor agonist isoproterenol rapidly stimulate cyclic adenosine monophosphate response element-binding protein (CREB) phosphorylation at Ser133 in human PDAC cells. Exposure to the nonselective β-adrenergic receptor antagonist propranolol or selective antagonists, including nebivolol, atenolol, or ICI118551, blocked CREB phosphorylation elicited by norepinephrine or isoproterenol in PDAC cells. Stimulation of PDAC cells with neurotensin, a neuropeptide implicated in obesity and PDAC, also stimulated CREB phosphorylation at Ser133. Mechanistically, norepinephrine induced CREB phosphorylation at Ser133 via PKA, whereas neurotensin promoted CREB phosphorylation predominantly through protein kinase D. Our results indicate that CREB is a point of signal convergence that mediates proliferation in PDAC cells and raised the possibility that stress and diet cooperate in promoting PDAC in vivo. To test this notion, mice expressing KrasG12D in all pancreatic lineages (KC mice) and fed an obesogenic high fat, calorie diet that promotes early PDAC development were subjected to social isolation stress. We show that social isolation stress induced a significant increase in the proportion of advanced PDAC precursor lesions (pancreatic intraepithelial neoplasia) in KC mice subjected to an obesogenic high fat, calorie diet. Implications: Our data imply that chronic (social isolation) stress cooperates with diet-induced obesity in accelerating the development of pancreatic cancer.

Investigating combined hypoxia and stemness indices for prognostic transcripts in gastric cancer: Machine learning and network analysis approaches

Introduction

Gastric cancer (GC) is among the deadliest malignancies globally, characterized by hypoxia-driven pathways that promote cancer progression, including stemness mechanisms facilitating invasion and metastasis. This study aimed to develop a prognostic decision tree using genes implicated in hypoxia and stemness pathways to predict outcomes in GC patients.

Materials and methods

GC RNA-seq data from The Cancer Genome Atlas (TCGA) were analyzed to compute hypoxia and stemness scores using Gene Set Variation Analysis (GSVA) and the mRNA expression-based stemness index (mRNAsi). Hierarchical clustering identified clusters with distinct survival outcomes, and differentially expressed genes (DEGs) between clusters were identified. Weighted Gene Co-expression Network Analysis (WGCNA) identified modules and hub genes associated with clinical traits. Overlapping DEGs and hub genes underwent functional enrichment, protein-protein interaction (PPI) network analysis, and survival analysis. A prognostic decision tree was constructed using survival-associated shared genes.

Results

Hierarchical clustering identified six clusters among 375 TCGA GC patients, with significant survival differences between cluster 1 (low hypoxia, high stemness) and cluster 4 (high hypoxia, high stemness). Validation in the GSE62254 dataset corroborated these findings. WGCNA revealed modules linked to clinical traits and survival, with functional enrichment highlighting pathways like cell adhesion and calcium signaling. The decision tree, based on genes such as AKAP6, GLRB, and RUNX1T1, achieved an AUC of 0.81 (training) and 0.67 (test), demonstrating the utility of combined scores in patient stratification.

Conclusion

This study introduces a novel hypoxia-stemness-based prognostic decision tree for GC. The identified genes show promise as prognostic biomarkers, warranting further clinical validation.

VGF and the VGF-derived peptide AQEE30 stimulate osteoblastic bone formation through the C3a receptor

New therapeutic targets, especially those that stimulate bone formation in cortical bone, are needed to overcome the limitations of current antiosteoporotic drugs. We previously demonstrated that factors secreted from megakaryocytes (MKs) promote bone formation. Here we conducted a proteomic analysis to identify a novel bone-forming factor from MK secretions. We revealed that Vgf, a nerve growth factor-responsive gene, and its derived active peptide AQEE30 in MK-conditioned medium play important roles in osteoblast proliferation and in vitro bone formation. In both Vgf-deficient male and female mice, the cortical bone mass was significantly decreased due to reductions in osteoblast number and bone formation activity. AQEE30 stimulated intracellular cyclic adenosine monophosphate (cAMP) levels and protein kinase A (PKA) activity in osteoblasts, whereas an adenylyl cyclase inhibitor blocked AQEE30-stimulated osteoblast proliferation and in vitro bone formation. Complement C3a receptor-1 (C3AR1) was expressed and interacted with AQEE30 in osteoblasts, and C3AR1 inhibition blocked all AQEE30-induced changes, including stimulated proliferation, bone formation and cAMP production, in osteoblasts. Injecting mini-PEGylated AQEE30 into calvaria increased the number of osteocalcin-positive cells and new bone formation. In conclusion, this study reveals a novel role of VGF in bone formation, particularly in cortical bone, and shows that AQEE30, a VGF-derived peptide, mediates this role by activating cAMP-PKA signaling via the C3AR1 receptor in osteoblasts.

Pde4b-regulated cAMP signaling pathway in the AUDGABA-S1TrSst circuit underlies acute-stress-induced anxiety-like behavior

Acute-stress-induced anxiety helps animals avoid danger, but the neural and molecular mechanisms controlling this behavior remain largely elusive. Here, we find that acute physical stress activates many neurons in the primary somatosensory cortex, trunk region (S1Tr). Single-cell sequencing reveals that the S1Tr c-fos-positive neurons activated by acute stress are largely GABAergic somatostatin (Sst) neurons. These S1TrSst neurons desensitize during subsequent anxiety-like behavior tests. Inhibiting or inducing apoptosis of S1TrSst neurons mimics acute-stress effects and induces anxiety, while activating these neurons reduces acute-stress-induced anxiety. S1TrSst cells receive inputs from secondary auditory cortex, dorsal area (AUD) GABAergic neurons to modulate this anxiety. Spatial transcriptome sequencing and targeted Pde4b protein knockdown show that acute stress reduces Pde4b-regulated cAMP signaling in AUDGABA-S1TrSst projections, leading to decreased S1TrSst neuron activity in subsequent behavioral tests. Our study reports a neural and molecular mechanism for acute-stress-induced anxiety, providing a basis for treating anxiety disorders.

Identification of a novel hypermethylation marker, ZSCAN18, and construction of a diagnostic model in cervical cancer

PURPOSE

Cervical cancer (CC), a common female malignancy, has been linked to alterations in DNA methylation. This study employed an integrated "dry-wet lab" strategy combining bioinformatics, machine learning, and experimental validation to identify novel methylation biomarkers for CC.

METHODS

Methylome and transcriptome data from the TCGA and GEO cohorts (n=349 discovery, n=414 validation) were analyzed to identify differentially methylated CpGs. The top candidates were validated by pyrosequencing, methylation-specific PCR, and quantitative assays. Diagnostic models were developed, and functional studies were performed for the target markers.

RESULTS

Eighteen differentially methylated CpGs were identified, with five top candidates (three in the ZSCAN18 promoter) showing diagnostic potential. ZSCAN18 promoter methylation levels and positivity rates were significantly greater in CC tissues than in normal tissues (p<0.05), reaching 77.8% (21/27) in ThinPrep cytology test (TCT) samples. The ridge regression diagnostic model achieved an AUC of 0.9421 in the validation cohort. Similarly, ZSCAN18 overexpression suppressed CC cell proliferation (p<0.05).

CONCLUSIONS

This study established a rapid, effective and systematic systemic research strategy to screen novel methylation markers for CC. ZSCAN18 promoter methylation correlates with cervical lesion severity, and the diagnostic model enhances the diagnostic ability. These findings highlight the dual role of ZSCAN18 as a diagnostic marker and potential therapeutic target.

Etomidate Induces Mitochondrial Dysfunction in Glioma Cancer Cells by Inhibiting Mitochondrial Biogenesis Mediated by CREB/PGC-1α

Gliomas are one of the most prevalent types of solid tumors in the brain. Imbalances in mitochondrial metabolism have been implicated in the pathological progression of gliomas. Etomidate, an agonist of the γ-aminobutyric acid type A (GABAA) receptor, is widely used in clinical settings. In this study, we report a novel pharmacological function of etomidate in regulating mitochondrial metabolism in glioma cancer cells. U87 glioma tumor cells were treated with etomidate (0.5, 1.0, and 2.0 µg/mL) for 24 h. Quantitative real-time PCR, western blot analysis, mtDNA/nDNA ratio, MitoTracker Red staining, Complex I and IV activity, intracellular ATP levels, and mitochondrial respiration were assessed. First, etomidate exposure inhibited the expression of PGC-1α in U87 glioma tumor cells. Further investigation revealed that etomidate suppressed the expression of Nrf1 and TFAM, the two key executors of mitochondrial biogenesis. Etomidate treatment led to damage in mitochondrial biogenesis by decreasing the mtDNA/nDNA ratio, reducing the protein expression of cytochrome B, and lowering mitochondrial mass. These changes suggest impaired mitochondrial replication and function. Correspondingly, etomidate exposure induced a "loss of mitochondrial function" by diminishing the activities of Complex I and Complex IV, the mitochondrial respiratory rate (MRR), and ATP generation. These effects highlight the detrimental impact of etomidate on the energy metabolism of glioma cells. Mechanistically, etomidate inactivated the transcription factor CREB by reducing its phosphorylation at Ser133. Activation of CREB with the second messenger cAMP restored the expression of PGC-1α, the mtDNA/nDNA ratio, Complex IV activity, summarized mitochondrial respiratory rate (MRR), and ATP production. This suggests that CREB activation may serve as a potential therapeutic strategy to counteract etomidate's inhibitory effects on mitochondrial function in glioma cells. Our results suggest that damage to mitochondrial biogenesis is a key step in the anticancer properties of etomidate in gliomas, and the decrease in PGC-1α and its downstream molecules may be the critical mechanism behind this effect.

Syringa oblata Lindl extract alleviated corticosterone-induced depression via the cAMP/PKA-CREB-BDNF pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Syringa oblata Lindl (ZDX) is a plant in the Oleaceae family that is the primary ingredient in the classic Tibetan medicine AKARU sinensis. The plant's stem is used as a medicine, and Tibetan doctors often use it as a sedative, a use with a history of nearly 100 years. Tibetan medicine mainly uses lilac to treat headache, forgetfulness, insomnia, irritability and other symptoms. Depression is a chronic mental disorder characterized by low mood, cognitive impairments, and physical discomfort, and it has become a significant public health issue. Given the limitations of existing treatments, interest in alternative therapies, including herbal medicines, is increasing.

AIM

To elucidate the mechanism of ZDX extract in the treatment of depression.

MATERIALS AND METHODS

A depression-like mouse model was established via the subcutaneous injection of corticosterone (CORT) into the groin, and a model of PC12 cell injury was established via CORT treatment. The antidepressant effect of the ZDX extract was subsequently evaluated via weight measurements, the sucrose preference test (SPT), the forced swimming test (FST), the open field test(OFT), the tail suspension test (TST), HE staining, Nissl staining and ELISA. Moreover, immunofluorescence staining, qRT‒PCR and Western blotting were used to determine whether ZDX extract can regulate the cAMP/PKA-CREB-BDNF pathway to prevent depression and neuronal apoptosis.

RESULTS

ZDX extract significantly improved depression-like behaviours; inhibited decreases in the protein levels of cAMP, PKA, CREB and BDNF; and increased proliferative activity in the hippocampus and cortex. In addition, in vitro, ZDX extract attenuated CORT-induced injury and apoptosis in hippocampal neurons and inhibited CORT-induced decreases in the mRNA expression levels of cAMP, PKA, CREB and BDNF.

CONCLUSIONS

These findings suggest that ZDX extract has potential as a novel antidepressant therapeutic agent, offering a complementary approach to current treatments by targeting multiple pathways involved in the pathogenesis of depression. Further research is warranted to explore the clinical applications of ZDX extract in the treatment of depression.

Repeated-Dose Toxicity of Lauric Acid and Its Preventive Effect Against Tracheal Hyper-Responsiveness in Wistar Rats with Possible In Silico Molecular Targets

BACKGROUND/OBJECTIVES

Lauric acid (LA), a medium-chain fatty acid, is a promising drug for asthma treatment. This study evaluated the toxicity of repeated doses and the effect of LA on pulmonary ventilation and tracheal reactivity in asthmatic Wistar rats and identified possible molecular targets of LA action in silico.

METHODS

The rats were divided into control (CG) and LA-treated groups at 100 mg/kg (AL100G) for toxicity analysis. Pulmonary ventilation and tracheal reactivity were assessed in the control (CG), asthmatic (AG), asthmatic treated with LA at 25, 50, or 100 mg/kg (AAL25G, AAL50G, and AAL100G), and dexamethasone-treated groups (ADEXAG).

RESULTS

The results showed that LA at a dose of 100 mg/kg did not cause death or toxicity. A pulmonary ventilation analysis indicated that AG had reduced minute volume, which was prevented in AAL25G. LA at all doses prevented carbachol-induced tracheal hyper-responsiveness and reduced the relaxing effect of aminophylline, as observed in AG. An in silico analysis revealed that LA had a good affinity for nine proteins (β2-adrenergic receptor, CaV, BKCa, KATP, adenylyl cyclase, PKG, eNOS, iNOS, and COX-2).

CONCLUSIONS

LA at 100 mg/kg has low toxicity, prevents hyper-responsiveness in an asthma model in rats, and acts as a multitarget compound with a good affinity for proteins related to airway hyper-responsiveness.

The PDE4DIP-AKAP9 axis promotes lung cancer growth through modulation of PKA signalling

Phosphodiesterase 4D interacting protein (PDE4DIP) is a Golgi/centrosome-associated protein that plays critical roles in the regulation of microtubule dynamics and maintenance of the Golgi structure. However, its biological role in human cancer remains largely unknown. In this study, we showed that PDE4DIP is overexpressed in human non-small cell lung cancer (NSCLC) tissues and that upregulated PDE4DIP expression is associated with poor prognosis in patients with lung cancer. We demonstrated that PDE4DIP knockdown inhibits NSCLC cell proliferation in vitro and tumorigenicity in vivo. We further demonstrated that PDE4DIP knockdown triggers apoptosis and cell cycle arrest in NSCLC cells by activating the Protein kinase A (PKA) /CREB signalling pathway. PDE4DIP coordinates with A-kinase anchoring proteins 9 (AKAP9) to enhance the Golgi localization and stability of PKA RIIα. Depletion of PDE4DIP mislocalizes PKA RIIα from the Golgi and leads to its degradation, thereby compromising its negative regulatory effect on PKA signalling. Overall, our findings provide novel insights into the roles of the PDE4DIP-AKAP9 complex in regulating PKA signalling and NSCLC growth and highlight PDE4DIP as a promising therapeutic target for NSCLC.

Shenghui decoction inhibits neuronal cell apoptosis to improve Alzheimer's disease through the PDE4B/cAMP/CREB signaling pathway

BACKGROUND

Shenghui Decoction (SHD) is a frequently utilized traditional Chinese medicine formula in clinical settings for addressing cognitive impairment in elderly individuals. Nevertheless, the precise mechanism by which SHD exerts its effects on the most prevalent form of dementia, Alzheimer's disease (AD), remains to be elucidated.

METHODS

Temperature-induced transgenic C. elegans assess Aβ deposition and toxicity. Behavioral experiments are utilized to assess learning and memory capabilities as well as cognitive impairment in APP/PS1 mice. Immunofluorescence and immunohistochemistry are employed to identify Aβ deposits, while UHPLCOE/MS combine network pharmacology is utilized to characterize chemical composition, predict target and analyze the biological processes and signaling pathways modulated by SHD. Molecular biology methodologies confirm the functionality of regulatory pathways. Molecular docking, molecular dynamic simulations (MD) and ultrafiltration-liquid chromatography/mass spectrometry (LC/MS) are employed for the assessment of the binding interactions between active ingredients of SHD and target proteins.

RESULTS

SHD effectively reduced the deposition of Aβ in the head of C. elegans and mitigated its toxicity, as well as improved the learning deficits and cognitive impairment in APP/PS1 mice. Network pharmacology analyses revealed that G protein-coupled receptors (GPCRs) and cell apoptosis are the primary biological processes modulated by SHD, with KEEG results indicating that SHD regulated the cAMP signaling pathway. Subsequent experimental investigations demonstrated that SHD attenuated the loss of neurons in APP/PS1 mice, upregulated the expression of anti-apoptotic protein Bcl-2 and downregulated the expression of pro-apoptotic proteins like cleave-Caspase-3 both in vivo and in vitro. Additionally, SHD decreased intracellular AMP levels while increasing cAMP levels, leading to the phosphorylation of PKA to activate CREB. This process ultimately regulated the expression of Bcl-2, Bdnf, among others, to prevent cell apoptosis and safeguard neurons. Molecular docking, MD, and ultrafiltration-LC/MS revealed that the active constituents of SHD formed stable interactions with the cAMP hydrolysis enzyme phosphodiesterase 4B (PDE4B).

CONCLUSION

SHD regulated the cAMP/CREB signaling pathway to inhibit neuronal cell apoptosis and improve AD. Furthermore, it is worth noting that this mechanism may be associated with the specific and consistent binding of SHD active ingredients to PDE4B, potentially offering promising candidates for drug development aimed at addressing AD.

Molecular Mechanisms and Strategies for Inducing Neuronal Differentiation in Glioblastoma Cells

Glioblastoma multiforme (GBM) is a highly invasive brain tumor, and traditional treatments combining surgery with radiochemotherapy have limited effects, with tumor recurrence being almost inevitable. Given the lack of proliferative capacity in neurons, inducing terminal differentiation of GBM cells or glioma stem cells (GSCs) into neuron-like cells has emerged as a promising strategy. This approach aims to suppress their proliferation and self-renewal capabilities through differentiation. This review summarizes the methods involved in recent research on the neuronal differentiation of GBM cells or GSCs, including the regulation of transcription factors, signaling pathways, miRNA, and the use of small molecule drugs, among various strategies. It also outlines the interconnections between the mechanisms studied, hoping to provide ideas for exploring new therapeutic avenues for GBM and the development of differentiation-inducing drugs for GBM.

Missense mutations of GPER1 in breast invasive carcinoma: Exploring gene expression, signal transduction and immune cell infiltration with insights from cellular pharmacology

G protein-coupled estrogen receptor 1 (GPER1) plays a crucial role in the progression of breast cancer and has emerged as a promising therapeutic target. However, while missense mutations in GPER1 have been detected in breast invasive carcinoma (BIC) samples, the resulting molecular, cellular and pharmacological changes remain unclear. The present study categorized BIC samples from The Cancer Genome Atlas database based on mutation information available in the cBioPortal database. Subsequently, survival analysis was conducted and the samples screened for differentially expressed genes (DEGs). Using these DEGs, the present study performed Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, protein-protein interaction network analysis and hub gene selection. After assessing the prognostic value of hub genes, the immune cell infiltration between mutant and wild-type (WT) groups was analyzed. Finally, a luciferase reporter system was used to assess the cyclic AMP (cAMP) production mediated by GPER1 following treatment with the agonist G-1 for each mutation. The results revealed a significant decrease in progression-free survival and disease-specific survival in the GPER1 mutant group compared with the WT group. Gene expression analysis identified 60 DEGs, all of which were upregulated and significantly enriched in GO terms related to tumor progression, such as organic anion transport, glycosaminoglycan binding and monoatomic ion-gated channel activity. DEGs were also significantly enriched in the PI3K-Akt signaling pathway in KEGG. Hub gene selection and prognostic evaluation identified three genes significantly associated with survival: IL33, STAB2 and CFTR. Immune cell infiltration analysis revealed a significant decrease in CD8 T cell content in the GPER1 mutant group compared with the WT group. Luciferase reporter assays demonstrated that four missense mutations in GPER1 (L129M, E218Q, S235F and A345G) significantly attenuated the induction of cyclic adenosine monophosphate production mediated by its agonist. These findings provided valuable insights for the design of breast cancer drugs targeting GPER1 and for precision medicine initiatives.

Slide-Ring Structured Stress-Electric Coupling Hydrogel Microspheres for Low-Loss Transduction Between Tissues

High transductive loss at tissue injury sites impedes repair. The high dissipation characteristics in the electromechanical conversion of piezoelectric biomaterials pose a challenge. Therefore, supramolecular engineering and microfluidic technology is utilized to introduce slide-ring polyrotaxane and conductive polypyrrole to construct stress-electric coupling hydrogel microspheres. The molecular slippage mechanism of slide-ring structure stores and releases mechanical energy, reducing mechanical loss, the piezoelectric barium titanate enables stress-electricity conversion, and conjugated π-electron movement in conductive network improves the internal electron transfer efficiency of microspheres, thereby reducing the loss in stress-electricity conversion for the first time. Compared to traditional piezoelectric hydrogel microspheres, the stress-electric coupling efficiency of low-dissipation microspheres increased by 2.3 times, and the energy dissipation decreased to 43%. At cellular level, electrical signals generated by the microspheres triggered Ca2+ influx into stem cells and upregulated the cAMP signaling pathways, promoting chondrogenic differentiation. Enhanced electrical signals induced macrophage polarization to the M2 phenotype, reshaping inflammation and promoting tissue repair. In vivo, the low-dissipation microspheres restored low-loss transduction between tissues, alleviated cartilage damage, improved behavioral outcomes, and promoted the treatment of osteoarthritis in rats. Therefore, this study proposes a new strategy for restoring low-loss transduction between tissues, particularly in mechanically sensitive tissues.

CMAP prediction and experimental validation of Forskolin as a podocyte protective and anti-proteinuric drug for nephrotoxic serum-treated mice

Podocyte injury leads to proteinuria and glomerular diseases. Different podocyte injuries have distinct mechanisms. It is desirable to use a regimen that targets the mechanism of a given podocyte injury for a specific and improved result. However, the mechanisms of the most podocyte injuries are largely elusive, preventing optimal drug choices. Here, we test the feasibility of combining kidney single-cell RNA-seq databases and the Connectivity Map database (CMAP) to predict drugs for a specific podocyte injury. We downloaded glomerular single-cell RNA-seq dataset of nephrotoxic serum (NTS)-treated and control mice from the GEO, and compared their podocyte gene expression, resulting in identification of genes with altered expression in NTS-treated podocytes. GO and KEGG enrichment of them revealed activations of podocyte injurious NFκB, TNFα, AGE-RAGE, apoptosis, cellular senescence, MAPK, and p53 pathways, and dedifferentiation. CMAP analysis of the genes ranked Forskolin top 3. Indeed, we found that NTS-treated mice developed massive proteinuria, which was prevented by Forskolin, accompanied by pathological improvement of podocytes. In treating overdose NTS-induced severe podocyte injury, Forskolin exhibited a comparable efficacy as glucocorticoids (methylprednisolone). In vitro, Forskolin prevented NTS-induced cellular injury in cultured podocytes as shown by cell viability and cytoskeletal integrity assays. Mechanistically, Forskolin inhibited STAT3, p53, NFκB, FAK, and TGF-β pathways, while upregulated podocyte essential genes, WT1, SYNPO, and VEGFA, independently of NTS. In conclusion, Forskolin protects podocytes by directly inhibiting harmful pathways and the associated genes while enhancing podocyte essential gene expression independently of insults, resulting in an efficacy comparable with that of glucocorticoids in NTS-treated mice.

Comprehensive pan-cancer analysis reveals NTN1 as an immune infiltrate risk factor and its potential prognostic value in SKCM

Netrin-1 (NTN1) is a laminin-related secreted protein involved in axon guidance and cell migration. Previous research has established a significant connection between NTN1 and nervous system development. In recent years, mounting evidence indicates that NTN1 also plays a crucial role in tumorigenesis and tumor progression. For instance, inhibiting Netrin-1 has been shown to suppress tumor growth and epithelial-mesenchymal transition (EMT) characteristics in endometrial cancer. To further elucidate the influence of genes on tumors, we utilized a variety of machine learning techniques and found that NTN1 is strongly linked to multiple cancer types, suggesting it as a potential therapeutic target. This study aimed to elucidate the role of NTN1 in pan-cancer using multi-omics data and explore its potential as a prognostic biomarker in SKCM. Analysis of the TCGA, GTEx, and UALCAN databases revealed significant differences in NTN1 expression at both the mRNA and protein levels. Prognostic value was evaluated through univariate Cox regression and Kaplan-Meier methods. Mutation and methylation analyses were conducted using the cBioPortal and SMART databases. We identified genes interacting with and correlated to NTN1 through STRING and GEPIA2, respectively. Subsequently, we performed GO and KEGG enrichment analyses. The results suggested that NTN1 might be involved in crucial biological processes and pathways related to cancer development and progression, including cell adhesion, axon guidance, immune response, and various signaling pathways. We then explored the correlation between NTN1 and immune infiltration as well as immunotherapy using the ESTIMATE package, TIMER2.0, TISIDB, TIDE, TIMSO, and TCIA. The relationship between NTN1 and tumor heterogeneity, stemness, DNA methyltransferases, and MMR genes was also examined. Lastly, we constructed a nomogram based on NTN1 in SKCM and investigated its association with drug sensitivity. NTN1 expression was significantly associated with tumor immune infiltration, molecular subtypes, and clinicopathological features in various cancers. Genetic analysis revealed that Deep deletions were the most common type of NTN1 alteration. Additionally, a positive correlation was observed between NTN1 CNAs and its expression levels. In most cancers, NTN1 showed positive correlations with immune and stromal scores, as well as with specific immune cell populations. Its predictive value for immunotherapy response was comparable to that of tumor mutational burden. Furthermore, NTN1 exhibited positive correlations with tumor heterogeneity, stemness, DNA methyltransferase genes, and MMR genes. In SKCM, NTN1 was identified as an independent risk factor and demonstrated potential associations with multiple drugs. NTN1 exhibits substantial clinical utility as a prognostic marker and indicator of immune response across various tumor types. This comprehensive analysis provides insights into its potential implications in pan-cancer research.

Advances in Protein Kinase Regulation of Stress Responses in Fruits and Vegetables

Fruits and vegetables (F&Vs) are essential in daily life and industrial production. These perishable produces are vulnerable to various biotic and abiotic stresses during their growth, postharvest storage, and handling. As the fruit detaches from the plant, these stresses become more intense. This unique biological process involves substantial changes in a variety of cellular metabolisms. To counter these stresses, plants have evolved complex physiological defense mechanisms, including regulating cellular activities through reversible phosphorylation of proteins. Protein kinases, key components of reversible protein phosphorylation, facilitate the transfer of the γ-phosphate group from adenosine triphosphate (ATP) to specific amino acid residues on substrates. This phosphorylation alters proteins' structure, function, and interactions, thereby playing a crucial role in regulating cellular activity. Recent studies have identified various protein kinases in F&Vs, underscoring their significant roles in plant growth, development, and stress responses. This article reviews the various types of protein kinases found in F&Vs, emphasizing their roles and regulatory mechanisms in managing stress responses. This research sheds light on the involvement of protein kinases in metabolic regulation, offering key insights to advance the quality characteristics of F&Vs.

Epigenetic regulation-mediated disorders in dopamine transporter endocytosis: A novel mechanism for the pathogenesis of Parkinson's disease

Mechanisms such as DNA methylation, histone modifications, and non-coding RNA regulation may impact the endocytosis of dopamine transporter (DAT) by influencing processes like neuronal survival, thereby contributing to the initiation and progression of Parkinson's Disease (PD). Some small molecule inhibitors or natural bioactive compounds have the potential to modulate epigenetic processes, thereby reversing induced pluripotent stem cells (iPSCs) reprogramming and abnormal differentiation, offering potential therapeutic effects for PD. Although no specific DNA modification enzyme directly regulates DAT endocytosis, enzymes such as DNA methyltransferases (DNMTs) may indirectly influence DAT endocytosis by regulating the expression of genes associated with this process. DNA modifications impact DAT endocytosis by modulating key signaling pathways, including the (protein kinase C) PKC and D2 receptor (D2R) pathways. Key enzymes involved in RNA modifications that influence DAT endocytosis include m6A methyltransferases and other related enzymes. This regulation impacts the synthesis and function of proteins involved in DAT endocytosis, thereby indirectly affecting the process itself. RNA modifications regulate DAT endocytosis through various indirect pathways, as well as histone modifications. Key enzymes influence the expression of genes associated with DAT endocytosis by modulating the chromatin's accessibility and compaction state. These enzymes control the expression of proteins involved in regulating endocytosis, promoting endosome formation, and facilitating recycling processes. Through the modulation exerted by these enzymes, the speed of DAT endocytosis and recycling patterns are indirectly regulated, establishing a crucial epigenetic control point for the regulation of neurotransmitter transport. Based on this understanding, we anticipate that targeting these processes could lead to favorable therapeutic effects for early PD pathogenesis.

CDK4 inactivation inhibits apoptosis via mitochondria-ER contact remodeling in triple-negative breast cancer

The energetic demands of proliferating cells during tumorigenesis require close coordination between the cell cycle and metabolism. While CDK4 is known for its role in cell proliferation, its metabolic function in cancer, particularly in triple-negative breast cancer (TNBC), remains unclear. Our study, using genetic and pharmacological approaches, reveals that CDK4 inactivation only modestly impacts TNBC cell proliferation and tumor formation. Notably, CDK4 depletion or long-term CDK4/6 inhibition confers resistance to apoptosis in TNBC cells. Mechanistically, CDK4 enhances mitochondria-endoplasmic reticulum contact (MERCs) formation, promoting mitochondrial fission and ER-mitochondrial calcium signaling, which are crucial for TNBC metabolic flexibility. Phosphoproteomic analysis identified CDK4's role in regulating PKA activity at MERCs. In this work, we highlight CDK4's role in mitochondrial apoptosis inhibition and suggest that targeting MERCs-associated metabolic shifts could enhance TNBC therapy.

Exploring the Analgesic Effect of Acupuncture on Knee Osteoarthritis Based on MLT/cAMP/PKA/CREB Signaling Pathway

Background

Acupuncture is an effective treatment for knee osteoarthritis (KOA), reducing pain and improving function. While melatonin (MLT) has notable pain relief benefits, the analgesic mechanism of acupuncture in KOA and its relationship with melatonin are still unknown. This study aims to explore this mechanism.

Methods

In this work, the KOA rabbit model was constructed using the traditional Hulth method, and the therapeutic effect was assessed by the Lequesne MG score and Pain assessment by hot plate test. The pathological alterations of cartilage tissue were observed using hematoxylin and eosin (H&E) staining, Safranin O-fast green and MASSON staining to observe the pathological changes in cartilage tissue, and the efficacy was evaluated according to the principles of Mankin score and Osteoarthritis Research Society International (OARSI) score. Meanwhile, MLT in serum, cyclic adenosine monophosphate (cAMP) in cartilage, and matrix metalloproteinase-3 (MMP-3) in joint fluid were detected by enzyme-linked immunosorbent assay. In addition, the expression of aromatic L-amino acid N-acetyltransferase (AANAT), melatonin receptor 1 (MT1) and 2 (MT2) mRNAs in cartilage was determined by real-time quantitative reverse transcription-polymerase chain reaction, and the levels of proteins related to PKA/CREB signaling pathway were detected by Western blotting.

Results

Based on the results of Lequesne MG score and Pain assessment by hot plate test experimental data, the treatment group presented significant improvements in knee pain and overall function relative to OA (Osteoarthritis) group. Besides, according to results of histologic staining, Mankin and OARSI scores, articular cartilage degeneration of treatment group remarkably improved. In addition, acupuncture significantly reduced the expression of the inflammatory factor MMP-3 in knee joint fluid and significantly increased the levels of MLT, AANAT, MT1, MT2, cAMP, PKA and CREB.

Conclusion

By regulating sympathetic excitability, acupuncture may activate the MLT/cAMP/PKA/CREB signaling pathway, decrease inflammatory factor expression and slow down degradation of articular cartilage, resulting in the relief of knee pain.

GPR68 supports AML cells through the calcium/calcineurin pro-survival pathway and confers chemoresistance by mediating glucose metabolic symbiosis

Accumulating evidence demonstrates that the "Warburg effect" that glycolysis is enhanced even in the presence of oxygen existed in hematopoietic malignancies, contributing to extracellular acidosis. G-protein coupled receptor 68 (GPR68), as a proton sensing GPCR responding to extracellular acidosis, is expected to play a critical role in hematopoietic malignancies. In the present study, we found that GPR68 was overexpressed in acute myeloid leukemia (AML) cells, and GPR68 deficiency impaired AML cell survival in vitro and cell engraftment in vivo. Mechanistic studies revealed that unlike GPR68 regulates Calpain1 in myelodysplastic syndromes (MDS) cells, GPR68 deficiency reduced cytosolic Ca2+ levels and calcineurin (CaN) activity in AML cells through an NFAT-independent mechanism. Moreover, the decreased Ca2+ levels disturbed cellular respiration (i.e., oxidative phosphorylation, OxPhos) by inhibiting isocitrate dehydrogenase (IDH) activity; this was more pronounced when BCL2 was inhibited simultaneously. Interestingly, GPR68 inhibition also decreased aerobic glycolysis in AML cells in a Ca2+-independent manner, suggesting that GPR68 mediated glucose metabolic symbiosis. As glucose metabolic symbiosis and the heterogeneous dependencies on aerobic glycolysis and cellular respiration tremendously impact chemosensitivity, the inhibition of GPR68 potentiated the tumoricidal effect of first-line chemotherapeutic agents, including BCL-2 inhibitors targeting OxPhos and cytarabine (Ara-C) targeting glycolysis. Consistent with these in vitro observations, higher levels of GPR68 were associated with inferior clinical outcomes in AML patients who received chemotherapies. In short, GPR68 drives the Ca2+/CaN pro-survival pathway and mediates glucose metabolic pathways in AML cells. Targeting GPR68 eradicates AML cells and alleviates chemoresistance, which could be exploited as a therapeutic target.

Giant Centella asiatica, a novel cultivar rich in madecassoside and asiaticoside, suppresses α‑melanocyte‑stimulating hormone‑induced melanogenesis through MC1R binding

The present study investigated the anti‑melanogenesis effects of Giant Centella asiatica (GCA), a new cultivator of Centella asiatica (CA) cataloged by the Korea Forest Service in 2022, and compared its efficacy with that of traditional CA. GCA has a high yield per unit area and enhanced antioxidant properties. The anti‑melanogenic effects of GCA were investigated using B16F10 melanoma cells and a 3D human skin‑equivalent model. Key molecular mechanisms were elucidated through western blotting, cAMP assays and molecular docking studies. Focus was addressed on the effect of GCA on skin whitening by comparing the ability of a GCA extract to inhibit melanin production in B16F10 melanoma cells and a 3D human skin‑equivalent model to that of CA. The results showed that the GCA extracts more effectively reduced melanin production, which was attributed to their higher content of two active components, madecassoside and asiaticoside. Further investigation revealed that GCA primarily inhibited melanogenesis through the PKA‑cAMP response element‑binding (CREB)‑microphthalmia‑associated transcription factor (MITF) axis, a key regulatory pathway in melanin synthesis. Notably, the present study, to the best of our knowledge, is the first to demonstrate that madecassoside and asiaticoside, the two principal compounds in GCA, directly bound to MC1R, which contributed to the significant skin‑whitening effects. Moreover, GCA reduced melanin production in a 3D human skin‑equivalent model, showing efficacy within a complex skin environment. These results demonstrated the superior effectiveness of GCA to that of CA for skin anti‑melanogenesis, indicating its potential as a promising natural material for targeting pigmentation disorders.

Melanin-like nanoparticles slow cyst growth in ADPKD by dual inhibition of oxidative stress and CREB

Melanin-like nanoparticles (MNPs) have recently emerged as valuable agents in antioxidant therapy due to their excellent biocompatibility and potent capacity to scavenge various reactive oxygen species (ROS). However, previous studies have mainly focused on acute ROS-related diseases, leaving a knowledge gap regarding their potential in chronic conditions. Furthermore, apart from their well-established antioxidant effects, it remains unclear whether MNPs target other intracellular molecular pathways. In this study, we synthesized ultra-small polyethylene glycol-incorporated Mn2+-chelated MNP (MMPP). We found that MMPP traversed the glomerular filtration barrier and specifically accumulated in renal tubules. Autosomal dominant polycystic kidney disease (ADPKD) is a chronic genetic disorder closely associated with increased oxidative stress and featured by the progressive enlargement of cysts originating from various segments of the renal tubules. Treatment with MMPP markedly attenuated oxidative stress levels, inhibited cyst growth, thereby improving renal function. Interestingly, we found that MMPP effectively inhibits a cyst-promoting gene program downstream of the cAMP-CREB pathway, a crucial signaling pathway implicated in ADPKD progression. Mechanistically, we observed that MMPP directly binds to the bZIP DNA-binding domain of CREB, leading to competitive inhibition of CREB's DNA binding ability and subsequent reduction in CREB target gene expression. In summary, our findings identify an intracellular target of MMPP and demonstrate its potential for treating ADPKD by simultaneously targeting oxidative stress and CREB transcriptional activity.

Taste receptor T1R3 regulates testosterone synthesis via the cAMP-PKA-SP1 pathway in testicular Leydig cells

Taste receptor type 1 subunit 3 (T1R3) is a G protein-coupled receptor encoded by the TAS1R3 gene that can be specifically activated by certain sweeteners or umami agents for sweet/umami recognition. T1R3 is a potential target for regulating male reproduction. However, studies on the impact of non-nutritive sweeteners on reproduction are limited. In the present study, we evaluated the impact of the non-nutritive sweeteners (saccharin sodium, sucralose and acesulfame-K) on testosterone synthesis in testicular Leydig cells of Xiang pigs by comparing the relative abundance of mRNA transcripts and protein expression of T1R3, steroidogenic related factors, and intracellular cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), as well as testosterone levels using Western blotting, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). To clarify the specific mechanism, a dual luciferase assay was used to uncover the relationship between the transcription factors and steroidogenic enzyme. The acute intratesticular injection of a typical non-nutritive sweeteners was conducted to verify this impact in mouse. The results showed that saccharin sodium not only enhanced T1R3 expression in Leydig cells of Xiang pigs, but also caused significant increases in testosterone, cAMP, PKA, phosphorylation of specificity protein 1 (p-SP1), total protein of specificity protein 1 (SP1), steroidogenic acute regulatory protein (StAR), and 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD1) (P < 0.05). Similarly, treatment of Leydig cells with sucralose and acesulfame-K also increased testosterone level, protein expression of T1R3, 17-α-hydroxylase/17, 20-lyase (CYP17A1), and 3β-HSD1 (P < 0.05). Treatment with SQ22536 (an adenylate cyclas inhibitor) or H89 (a PKA inhibitor) significantly reduced saccharin sodium-induced protein levels of p-SP1, StAR, CYP17A1, and 3β-HSD1 (P < 0.05). In addition, a dual luciferase assay further demonstrated that SP1 significantly increased the promoter activity of CYP17A1 (P < 0.05). When mouse testes were injected with saccharin sodium, T1R3, p-SP1, CYP17A1, and 3β-HSD1 were upregulated, leading to a significant testicular increase in testosterone and cAMP levels (P < 0.05). These results suggest a mechanism by which the taste receptor T1R3 regulates testosterone production, and this mechanism may be linked to the cAMP-PKA pathway. Understanding the interrelationship between T1R3 and the cAMP-PKA-SP1 pathway contributes to clarify the regulatory mechanisms of male reproduction.

Harnessing Microbial Signal Transduction Systems in Natural and Synthetic Consortia for Biotechnological Applications

Signal transduction is crucial for communication and cellular response in microbial communities. Consortia rely on it for effective communication, responding to changing environmental conditions, establishing community structures, and performing collective behaviors. Microbial signal transduction can be through quorum sensing (QS), two-component signal transduction systems, biofilm formation, nutrient sensing, chemotaxis, horizontal gene transfer stress response, and so forth. The consortium uses small signaling molecules in QS to regulate gene expression and coordinate intercellular communication and behaviors. Biofilm formation allows cells to adhere and aggregate, promoting species interactions and environmental stress resistance. Chemotaxis enables directional movement toward or away from chemical gradients, promoting efficient resource utilization and community organization within the consortium. In recent years, synthetic microbial consortia have gained attention for their potential applications in biotechnology and bioremediation. Understanding signal transduction in natural and synthetic microbial consortia is important for gaining insights into community dynamics, evolution, and ecological function. It can provide strategies for biotechnological innovation for enhancing biosensors, biodegradation, bioenergy efficiency, and waste reduction. This review provides compelling insight that will advance our understanding of microbial signal transduction dynamics and its role in orchestrating microbial interactions, which facilitate coordination, cooperation, gene expression, resource allocation, and trigger specific responses that determine community success.

Recent pharmacological insights on abating toxic protein species burden in neurological disorders: Emphasis on 26S proteasome activation

Protein homeostasis (proteostasis) refers to the plethora of mechanisms that safeguard the proper folding of the newly synthesized proteins. It entails various intricately regulated cues that demolish the toxic protein species to prevent their aggregation. The ubiquitin-proteasome system (UPS) is recognized as a salient protein degradation system, with a substantial role in maintaining proteostasis. However, under certain circumstances the protein degradation capacity of the UPS is overwhelmed, leading to the accumulation of misfolded proteins. Several neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, Huntington disease, and amyotrophic lateral sclerosis are characterized with the presence of protein aggregates and proteinopathy. Accordingly, enhancing the 26S proteasome degradation activity might delineate a pioneering approach in targeting various proteotoxic disorders. Regrettably, the exact molecular approaches that enhance the proteasomal activity are still not fully understood. Therefore, this review aimed to underscore several signaling cascades that might restore the degradation capacity of this molecular machine. In this review, we discuss the different molecular components of the UPS and how 26S proteasomes are deleteriously affected in many neurodegenerative diseases. Moreover, we summarize different signaling pathways that can be utilized to renovate the 26S proteasome functional capacity, alongside currently known druggable targets in this circuit and various classes of proteasome activators.

Metabolic reprogramming by mutant GNAS creates an actionable dependency in intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

Oncogenic 'hotspot' mutations of KRAS and GNAS are two major driver alterations in intraductal papillary mucinous neoplasms (IPMNs), which are bona fide precursors to pancreatic ductal adenocarcinoma. We previously reported that pancreas-specific Kras G12D and Gnas R201C co-expression in p48Cre; KrasLSL-G12D; Rosa26LSL-rtTA; Tg (TetO-GnasR201C) mice ('Kras;Gnas' mice) caused development of cystic lesions recapitulating IPMNs.

OBJECTIVE

We aim to unveil the consequences of mutant Gnas R201C expression on phenotype, transcriptomic profile and genomic dependencies.

DESIGN

We performed multimodal transcriptional profiling (bulk RNA sequencing, single-cell RNA sequencing and spatial transcriptomics) in the 'Kras;Gnas' autochthonous model and tumour-derived cell lines (Kras;Gnas cells), where Gnas R201C expression is inducible. A genome-wide CRISPR/Cas9 screen was conducted to identify potential vulnerabilities in KrasG12D;GnasR201C co-expressing cells.

RESULTS

Induction of Gnas R201C-and resulting G(s)alpha signalling-leads to the emergence of a gene signature of gastric (pyloric type) metaplasia in pancreatic neoplastic epithelial cells. CRISPR screening identified the synthetic essentiality of glycolysis-related genes Gpi1 and Slc2a1 in Kras G12D;Gnas R201C co-expressing cells. Real-time metabolic analyses in Kras;Gnas cells and autochthonous Kras;Gnas model confirmed enhanced glycolysis on Gnas R201C induction. Induction of Gnas R201C made Kras G12D expressing cells more dependent on glycolysis for their survival. Protein kinase A-dependent phosphorylation of the glycolytic intermediate enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) was a driver of increased glycolysis on Gnas R201C induction.

CONCLUSION

Multiple orthogonal approaches demonstrate that Kras G12D and Gnas R201C co-expression results in a gene signature of gastric pyloric metaplasia and glycolytic dependency during IPMN pathogenesis. The observed metabolic reprogramming may provide a potential target for therapeutics and interception of IPMNs.

Targeting chaperone modifications: Innovative approaches to cancer treatment

Cancer and other chronic diseases are marked by alterations in the protein quality control system, affecting the posttranslational destiny of various proteins that regulate, structure, and catalyze cellular processes. Cellular chaperones, also known as heat shock proteins (HSPs), are pivotal in this system, performing protein triage that often determines the fate of proteins they bind to. Grasping the regulatory mechanisms of HSPs and their associated cofactors is crucial for understanding protein quality control in both healthy and diseased states. Recent research has shed light on the interactions within the protein quality control system and how post-translational modification govern protein interactions, function, and localization, which can drive or inhibit cell proliferation. This body of work encompasses critical elements of the heat shock response, including heat shock protein 70, heat shock protein 90, carboxyl-terminus of HSC70 interacting protein, and heat shock protein organizing protein. This review aims to synthesize these advancements, offering a holistic understanding of the system and its response when commandeered by diseases like cancer. We focus on the mechanistic shift in co-chaperone engagement-transitioning from heat shock protein organizing protein to carboxyl-terminus of HSC70 interacting protein in association with heat shock protein 70 and heat shock protein 90-which could influence cellular growth and survival pathways. A comprehensive examination of posttranslational modification-driven regulation within the protein quality control network is presented, highlighting the roles of activation factors, chaperones, and co-chaperones. Our insights aim to inform new strategies for therapeutically targeting diseases by considering the entire heat shock response system.

AKT kinases as therapeutic targets

AKT, or protein kinase B, is a central node of the PI3K signaling pathway that is pivotal for a range of normal cellular physiologies that also underlie several pathological conditions, including inflammatory and autoimmune diseases, overgrowth syndromes, and neoplastic transformation. These pathologies, notably cancer, arise if either the activity of AKT or its positive or negative upstream or downstream regulators or effectors goes unchecked, superimposed on by its intersection with a slew of other pathways. Targeting the PI3K/AKT pathway is, therefore, a prudent countermeasure. AKT inhibitors have been tested in many clinical trials, primarily in combination with other drugs. While some have recently garnered attention for their favorable profile, concern over resistance and off-target effects have continued to hinder their widespread adoption in the clinic, mandating a discussion on alternative modes of targeting. In this review, we discuss isoform-centric targeting that may be more effective and less toxic than traditional pan-AKT inhibitors and its significance for disease prevention and treatment, including immunotherapy. We also touch on the emerging mutant- or allele-selective covalent allosteric AKT inhibitors (CAAIs), as well as indirect, novel AKT-targeting approaches, and end with a briefing on the ongoing quest for more reliable biomarkers predicting sensitivity and response to AKT inhibitors, and their current state of affairs.