Key Signal Transduction Pathways Research Articles

Identification of candidate biomarkers and prognostic analysis of recurrence in colorectal cancer.

Colorectal cancer (CRC) is one of the most common digestive tract malignant tumors, which has a high mortality rate especially for patients with CRC recurrence. However, the pathological mechanism of recurrence of CRC is unclear. In this study, we integrated multiple cohort datasets and databases to clarify and verify potential key candidate biomarkers and signal transduction pathways in recurrence of CRC. As results, 628 DEGs were identified from GSE33113 and GSE2630 datasets and their function and pathway were analyzed. 14 hub genes related to CRC recurrence were screened from and their influence on survival were analyzed. Two key genes (IL1B and DDAH1) regarded as prognostic factors were further screened. Relapse-free survival results indicated the interaction between IL1B and DDAH1 genes and B cells was the most obvious and correlated with survival, with statistical significance (P< 0.05). Specially, cox regression analysis suggested that patients with T1 and N0 stages had a higher risk of recurrence than patients with T2 and N1. This work would provide potential value for prognosis, and would promote molecular targeting therapy for CRC recurrence.

Effect of impaired autophagic flux on breast carcinogenesis through the enhanced LC3-p62-NRF2 feedback loop.

6 Background: Breast cancer affects more women worldwide than any other type of cancer. Although some genes have been identified as potential causes, the exact molecular mechanism of the disease is still unknown. In our study, we aimed to investigate the role of NRF2 and the autophagy markers p62 and LC3 in breast cancer cell lines that have different Tp53 status using a new compound called 6,6'dihydroxythiobinupharidine (DTBN). In our previous research, we have shown that DTBN modulates key cellular signal transduction pathways that are relevant to disease biology, including cancer. Furthermore, we analyzed online databases to determine the correlation between NRF2, p62, LC3, and Tp53 in breast cancer patients. Methods: To evaluate the effect of DTBN on NRF2, p62 and LC3 in different types of breast cancer cell lines with varying TP53 status, we conducted molecular studies by inhibiting NRF2 activity. We synthesized the correlation between NRF2, p62, LC3 and TP53 expression and clinical parameters by analyzing TCGA and GEO datasets. Results: Our findings suggest that DTBN induces cell death and autophagy in all breast cancer cell lines, regardless of their Tp53 status. However, they also led us to hypothesize that NRF2 may hinder the sensitivity of cancer cells to DTBN-induced cell death and autophagy. To test this hypothesis, we inhibited NRF2 activity using an NRF2 inhibitor called brusatol. The results of the study indicate that the inhibition of NRF2 significantly increased cell death and autophagy in DTBN-treated cells. We observed a decrease in the expression of the autophagy marker p62, while an increase in the expression of another autophagy marker LC3. These findings suggest that the interaction between NRF2, LC3 and p62, which is activated in response to DTBN treatment, may serve as a potential anticancer drug target. We have validated the positive correlation between NRF2 and the autophagic gene p62 and LC3, in different Tp53 status breast cancer cell lines by analyzing TCGA and GEO data. Conclusions: Our study shows that high levels of Nrf2, LC3 and p62 expression are significantly associated with increased breast cancer cell proliferation and migration. This implies that patients with breast cancer have lower overall survival and a higher rate of recurrence. Our findings highlight the role of DTBN-induced NRF2 and LC3 expression and reduced p62 expression in breast cancer cells with varying Tp53 status. These results may represent a paradigm for better understanding the cancer cell response to therapies and designing more efficient combined anticancer therapies targeting NRF2, LC3 p62, and Tp53.

Kahweol Inhibits Pro-Inflammatory Cytokines and Chemokines in Tumor Necrosis Factor-α/Interferon-γ-Stimulated Human Keratinocyte HaCaT Cells.

Atopic dermatitis (AD), marked by intense itching and eczema-like lesions, is a globally increasing chronic skin inflammation. Kahweol, a diterpene that naturally occurs in coffee beans, boasts anti-inflammatory, antioxidative, and anti-cancer properties. This research explores the anti-inflammatory action of kahweol on HaCaT human keratinocytes stimulated by tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), focusing on key signal transduction pathways. Our results demonstrate that kahweol markedly reduces the production of IL-1β, IL-6, C-X-C motif chemokine ligand 8, and macrophage-derived chemokine in TNF-α/IFN-γ-activated HaCaT cells. Furthermore, it curtails the phosphorylation of key proteins in the mitogen-activated protein kinase (MAPK) pathways, including c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38. Additionally, kahweol impedes the phosphorylation and nuclear translocation of the NF-κB p65 subunit and constrains its DNA-binding capability. It also hampers the phosphorylation, nuclear translocation, and DNA-binding activities of signal transducer and activator of transcription 1 (STAT1) and STAT3. Collectively, these findings suggest that kahweol hinders the generation of cytokines and chemokines in inflamed keratinocytes by inhibiting the MAPK, NF-κB, and STAT cascades. These insights position kahweol as a promising agent for dermatological interventions, especially in managing inflammatory skin conditions such as AD.

Abstract 4604: Imipridones ONC201 and ONC212 exhibit anti-tumor activity in biliary tract cancers and synergy when combined with trametinib and olaparib in vitro

Abstract Background: Biliary tract cancers (BTCs) are an aggressive group of malignancies affecting 220,000 new individuals globally each year. Despite advances in immunotherapy and targeted therapies, 5-year survival remains at 2% for those with metastatic disease. Thus, new therapies are desperately needed. The novel imipridone class of antineoplastic agents show promising activity in preclinical pancreatic ductal adenocarcinoma models; however, have not been investigated in BTC. Dordaviprone (ONC201) is a dopamine receptor D2 and mitochondrial protease ClpP modulator that induces apoptosis in cancer cells through both upregulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and the integrated stress response. ONC212 is a second-generation imipridone that targets orphan GPCR 132 and ClpP, leading to reduced oxidative phosphorylation from ClpX suppression. We hypothesized that the ONC201 and ONC212 would demonstrate antitumor effects in BTCs, both alone, and in combination with MEK and PARP inhibition. Methods: Two established BTC cell lines, RBE and HuCCT1, were used for these experiments. Sensitivity of RBE and HuCCT1 cells to ONC201, ONC212, MEK inhibition (trametinib), and PARP inhibition (olaparib) was assessed using CellTiter-Glo® luminescent cell viability assay. Each cell line was plated on 96-well plates and treated with ONC201 concentrations ranging from 0uM to 40uM for RBE and 0uM to 32uM for HuCCT1; ONC212 ranging from 0nM to 752nM for RBE and 0nM to 640nM for HuCCT1; trametinib ranging from 0nM to 24nM for RBE and 0nM to 16nM for HuCCT1; and olaparib ranging from 0uM to 256uM for RBE and 0uM to 124uM for HuCCT1. Results were analyzed after 72 hours of incubation. Synergy studies were conducted in both cell lines, combining each imipridone with either trametinib or olaparib, and SynergyFinder® was used to evaluate synergy. Western blotting was performed on lysates generated from treated cell lines. Results: Both ONC201 and ONC212 demonstrated antineoplastic effects in two BTC cell lines. Half maximal inhibitory concentrations (IC50) of ONC201 in RBE and HuCCT1 cell lines were 2.5uM and 2.0uM, respectively. The IC50 of ONC212 in RBE and HuCCT1 was 47nM and 39nM, respectively, which was similar to IC50s demonstrated with cytotoxic chemotherapy (gemcitabine IC50 = 7.57nM (RBE) and 9.84nM (HuCCT1)). Both lines also demonstrated sensitivity to trametinib (IC50 = 5.9nM (RBE) and 3.7nM (HCCT1)), and to a lesser extent olaparib (IC50 = 64uM (RBE) and 31uM (HuCCT1)). Although synergy was noted with several combinations, this was most striking with the combination of ONC212 and either trametinib or olaparib. Further analysis of key signal transduction pathways, including MAPK and PI3K, as well as analysis of mechanisms of cell-death through apoptosis, autophagy, ferroptosis, and necroptosis is underway Citation Format: Grace Sun, Alexis J. Lannigan, Jasper Chan, Maximilian Schwermann, Varun V. Prabhu, Lanlan Zhou, Wafik S. El-Deiry, Alexander Grenander Raufi. Imipridones ONC201 and ONC212 exhibit anti-tumor activity in biliary tract cancers and synergy when combined with trametinib and olaparib in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4604.

Identification and prognostic analysis of candidate biomarkers for lung metastasis in colorectal cancer.

Colorectal cancer (CRC) is one of the most prevalent types of malignant tumors. It's vital to explore new biomarkers and potential therapeutic targets in CRC lung metastasis through adopting integrated bioinformatics tools. Multiple cohort datasets and databases were integrated to clarify and verify potential key candidate biomarkers and signal transduction pathways in CRC lung metastasis. DAVID, STRING, UALCAN, GEPIA, TIMER, cBioPortal, THE HUMAN PROTEIN ATLAS, GSEA 4.3.2, FUNRICH 3.1.3, and R 4.2.3 were utilized in this study. The enriched biological processes and pathways modulated by the differentially expressed genes (DEGs) were determined with Gene Ontology, Kyoto Encyclopedia of Genes and Genomes. The search tool Retrieval of Interacting Genes and Cytoscape were used to construct a protein-protein interaction network among DEGs. Four hundred fifty-nine colorectal primary cancer and lung metastatic gene expression profiles were screened from 3 gene expression profiles (GSE41258, GSE68468, and GSE41568). Forty-one upregulated genes and 8 downregulated genes were identified from these 3 gene expression profiles and verified by the transcriptional levels of hub genes in other GEO datasets and The Cancer Genome Atlas database. Two pathways (immune responses and chemokine receptors bind chemokines), 13 key DEGs, 6 hub genes (MMP3, SFTPD, ABCA3, CLU, APOE, and SPP1), and 2 biomarkers (APOE, SPP1) with significantly prognostic values were screened. Forty-nine DEGs were identified as potential candidate diagnostic biomarkers for patients with CRC lung metastasis in present study. Enrichment analysis indicated that immune responses and chemokine receptors bind chemokines may play a leading role in lung metastasis of CRC, and further studies are needed to validate these findings.

Integrative ATAC-seq and RNA-seq analysis associated with diabetic nephropathy and identification of novel targets for treatment by dapagliflozin.

Dapagliflozin (DAPA) are clinically effective in improving diabetic nephropathy (DN). However, whether and how chromatin accessibility changed by DN responds to DAPA treatment is unclear. Therefore, we performed ATAC-seq, RNA-seq, and weighted gene correlation network analysis to identify the chromatin accessibility, the messenger RNA (mRNA) expression, and the correlation between clinical phenotypes and mRNA expression using kidney from three mouse groups: db/m mice (Controls), db/db mice (case group), and those treated with DAPA (treatment group). RNA-Seq and ATAC-seq conjoint analysis revealed many overlapping pathways and networks suggesting that the transcriptional changes of DN and DAPA intervention largely occured dependently on chromatin remodeling. Specifically, the results showed that some key signal transduction pathways, such as immune dysfunction, glucolipid metabolism, oxidative stress and xenobiotic and endobiotic metabolism, were repeatedly enriched in the analysis of the RNA-seq data alone, as well as combined analysis with ATAC-seq data. Furthermore, we identified some candidate genes (UDP glucuronosyltransferase 1 family, Dock2, Tbc1d10c, etc.) and transcriptional regulators (KLF6 and GFI1) that might be associated with DN and DAPA restoration. These reversed genes and regulators confirmed that pathways related to immune response and metabolism pathways were critically involved in DN progression.

A literature review: mechanisms of antitumor pharmacological action of leonurine alkaloid.

Leonurine refers to the desiccated aerial portion of a plant in the Labiatae family. The primary bioactive constituent of Leonurine is an alkaloid, Leonurine alkaloid (Leo), renowned for its substantial therapeutic efficacy in the treatment of gynecological disorders, in addition to its broad-spectrum antineoplastic capabilities. Over recent years, the pharmacodynamic mechanisms of Leo have garnered escalating scholarly interest. Leo exhibits its anticancer potential by means of an array of mechanisms, encompassing the inhibition of neoplastic cell proliferation, induction of both apoptosis and autophagy, and the containment of oncogenic cell invasion and migration. The key signal transduction pathways implicated in these processes include the Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL), the Phosphoinositide3-Kinase/Serine/Threonine Protein Kinase (PI3K/AKT), the Signal Transducer and Activator of Transcription 3 (STAT3), and the Mitogen-Activated Protein/Extracellular Signal-Regulated Kinase (MAP/ERK). This paper commences with an exploration of the principal oncogenic cellular behaviors influenced by Leo and the associated signal transduction pathways, thereby scrutinizing the mechanisms of Leo in the antineoplastic sequence of events. The intention is to offer theoretical reinforcement for the elucidation of more profound mechanisms underpinning Leo's anticancer potential and correlating pharmaceutical development.

The effect of hormones insulin and glucagon on ubiquitin modifications elucidated by proteomics in liver cells

AimsInsulin action is intertwined with changing levels of glucose and counter-regulatory hormone glucagon. While insulin lowers blood sugar level, glucagon raises it by promoting the breakdown of the stored glycogen in liver and releases glucose into the bloodstream. The hormones insulin and glucagon are key in the pathogenesis of type 2 diabetes (T2D). Insulin resistance is a primary predisposing factor for diabetes. Phosphorylation of insulin signaling molecules is altered in the insulin-resistant state. However, ubiquitin (Ub) modifications in insulin-resistant state are relatively understudied. To dissect the underlying mechanisms, we performed a proteomics study on hepatoma cells to study the regulation of ubiquitination by insulin and glucagon. Materials and methodsWe performed western blotting, immunoprecipitations, and affinity pull down using tandem Ub binding entities (TUBE) reagents on hepatoma cells treated with insulin or glucagon. Next, we performed MS/MS analysis on Ub-linkage specific affinity pull down samples. Gene ontology analysis and protein-protein interaction network analysis was performed using DAVID GO and STRING db, respectively. Key findingsThe ubiquitination pattern of total Ub, K48-linked Ub, and K63-linked Ub was altered with the treatment of hormones insulin and glucagon. Ubiquitination in immunoprecipitated samples showed enrichment with total Ub and K48-linked Ub but not with K63-linked Ub. Ubiquitination by treatment with hormones mainly enriched key signaling pathways MAPK, Akt, oxidative stress etc. SignificanceOur study identified key altered proteins and signal transduction pathways which aids in understanding the mechanisms of hormonal action on ubiquitination and identify new therapeutic targets for T2D.

The Cell Death and Signal Transduction Mechanisms in Colorectal Carcinogenesis: Recent Advances.

In under developed nations, colorectal carcinogenesis (CRC) is a a significant health issue. It is the third most common outcome of cancer death. Despite a variety of therapy options, new medications are needed to lessen the severity of this condition. In the colon, Adenomatous polyps are the most common cause of CRC, occurring in 45 percent of cases, particularly in patients over 60 years old. Inflammatory polyps are acquiring popularity in CRC, as well as and inflammation appears to exert a function in the disease, according to mounting research. The Azoxymethane, Dimethyl hydrazine, APCmin/+ mouse model, and a combination of sulfated polysaccharide composed of dextran and sulfated and dimethylhydrazine are among the experimental models used to study CRC in animals. Numerous signal transduction pathways are engaged as CRC progresses. The p53, TGF-β, Delta-Notch,, Salvador-Warts-Hippo (SWH), and Kelch-like ECH assocd. protein 1pathways are among the key signal transduction pathways. To decide cell destiny, several signalling pathways work in tandem with death of cell modalitiessuch as autophagy, necroptosis, and apoptosis. In our lab, we've spent a lot of time looking into the Cell signalling and mechanisms of cell death in CRC. The pathogenesis of CRC, as well as the associated cell death and cell signalling pathways, are summarised in this study.

The new advance of SALL4 in cancer: Function, regulation, and implication.

SALL4 (split-like protein 4) is a member of the mammalian homologs of the Drosophila homoeotic gene spalt (sal) and acts as a zinc finger transcription factor to govern the self-renewal and pluripotency of embryonic stem cells. SALL4 expression gradually decreases during development and is even absent in most adult tissues. However, increasing evidence suggests that SALL4 expression is restored in human cancers and its aberrant expression is associated with the progression of many hematopoietic malignancies and solid tumors. The potent roles of SALL4 in regulating cancer cell proliferation, apoptosis, metastasis, and drug resistance have been reported. SALL4 plays a dual role in epigenetic modulation by acting as either an activator or a repressor of its target genes. Furthermore, SALL4 interacts with other partners to control the expression of many downstream genes and the activation of various key signaling transduction pathways. SALL4 is considered as a promising diagnostic and prognostic biomarker and therapeutic target for cancer. In this review, we highlighted the major advances in the roles and mechanisms of SALL4 in cancer and the therapeutic strategies for targeting SALL4 to treat cancer.

Abstract LB012: Claudin-1 is a driver and therapeutic target for cholangiocarcinoma

Abstract Introduction: Cholangiocarcinoma (CCA) shows an alarming rise in incidence and mortality with unsatisfactory treatment options. Claudin-1 (CLDN1), a member of the tight junction family, is a transmembrane protein mediating cell stemness, plasticity and signaling. The functional role of CLDN1 as a therapeutic target for CCA is unknown. We have previously developed highly specific monoclonal antibodies (mAb) targeting exposed non-junctional CLDN1 exhibiting an excellent safety profile in non-human primates (Roehlen, Saviano et al. Science Translational Medicine 2022). Here, we aimed to explore the role of CLDN1 as an oncogenic driver and therapeutic target for CCA. Methods: Comprehensive CLDN1 expression analyses in patient tissues were performed to evaluate CLDN1 as a therapeutic target. Proof-of-concept studies using CLDN1 mAbs were performed in state-of-the-art mouse CDX and PDX models including models for advanced metastatic disease. Single-cell RNA sequencing and proteomics were applied to investigate tumor cell fate and signaling in vivo and ex vivo models. Results: Comprehensive analyses of CLDN1 protein and RNA expression in CCA patient tissues revealed a marked and significant upregulation of CLDN1 in CCA. Single-cell RNA sequencing of the CCA microenvironment revealed strong expression in tumor cells showing EMT, cell cycle and interferon response signature, uncovering CLDN1 as a therapeutic target. Targeting exposed CLDN1 by highly specific mAbs resulted in a significant and robust antitumoral effect in vivo across CDX and PDX models for intra- and extrahepatic CCA including advanced metastatic disease. Functional studies in cell-based models of CCA showed that CLDN1 mAbs markedly and significantly suppressed migration and invasion of tumor cells. Mechanistically, treatment with CLDN1 mAb suppressed Notch1, Src, and Hippo-YAP signaling - key signal transduction pathways implicated in CCA development and progression. Conclusion: Collectively, these results support an important functional role for CLDN1 in CCA pathogenesis and provide robust pre-clinical proof-of-concept for CLDN1-specific mAbs to treat CCA, setting the stage for its clinical development. Citation Format: Marion Muller, Zeina Nehme, Emilie Crouchet, Frank Jühling, Natascha Röhlen, Patrick Pessaux, Emanuele Felli, Lipika Goyal, Markus Meyer, Roberto Iacone, Alberto Toso, Luigi Manenti, Patrice Laquerriere, Aïna Venkatasamy, Nabeel Bardeesy, Catherine Schuster, Laurent Mailly, Thomas F. Baumert. Claudin-1 is a driver and therapeutic target for cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB012.

Integrative ATAC-seq and RNA-seq analyses of IPEC-J2 cells reveals porcine transcription and chromatin accessibility changes associated with Escherichia coli F18ac inhibited by Lactobacillus reuteri.

Escherichia coli is the main cause of postweaning diarrhea in pigs, leading to economic loss. As a probiotic, Lactobacillus reuteri has been used to inhibit E. coli in clinical applications; however, its integrative interactions with hosts remain unclear, especially in pigs. Here, we found that L. reuteri effectively inhibited E. coli F18ac adhering to porcine IPEC-J2 cells, and explored the genome-wide transcription and chromatin accessibility landscapes of IPEC-J2 cells by RNA-seq and ATAC-seq. The results showed that some key signal transduction pathways, such as PI3K-AKT and MAPK signaling pathways, were enriched in the differentially expressed genes (DEGs) between E. coli F18ac treatment with and without L. reuteri groups. However, we found less overlap between RNA-seq and ATAC-seq datasets; we speculated that this might be caused by histones modification through ChIP-qPCR detection. Furthermore, we identified the regulation of the actin cytoskeleton pathway and a number of candidate genes (ARHGEF12, EGFR, and DIAPH3) that might be associated with the inhibition of E. coli F18ac adherence to IPEC-J2 cells by L. reuteri. In conclusion, we provide a valuable dataset that can be used to seek potential porcine molecular markers of E. coli F18ac pathogenesis and L. reuteri antibacterial activity, and to guide the antibacterial application of L. reuteri.

Temporal Changes in Key Signal Transduction Pathways Mediating Muscle Protein Synthesis with Adaptive and Maladaptive Right Ventricular Hypertrophy in Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is a progressive disease characterized by occlusive remodeling of pulmonary arteries &lt; 500 micron and increased pulmonary vascular resistance. With the onset of PAH, the right ventricle (RV) of the heart adapts to the increased afterload pressure by undergoing adaptive hypertrophic remodeling to maintain adequate blood flow. However, for unknown reasons, maladaptive influences ensue, resulting in impaired RV function with progressive decompensation and right heart failure. Using a rodent model of PAH, key signaling pathways mediating cardiac muscle protein synthesis in the RV were evaluated during both the adaptive hypertrophy phase, with preserved right heart function, and the decompensated maladaptive phase, in which right heart failure (RHF) was present. Analysis of protein and gene expression changes in PAH animals identified three key signaling pathways involved in the shift toward maladaptive right heart failure: i) PI3K/Akt/mTOR; ii) GSK-3; iii) MAPK/ERK, as well as IGF-1 regulation. During adaptive hypertrophy, significant increments of phosphorylated proteins in the three signaling pathways were observed with increases in RV fibrosis and decreased capillarity found. In the maladaptive phase, mTORC1 and its downstream effector p-70S6K were significantly activated, contributing to the decreased LC3-I/II ratio, a marker of autophagy inhibition together with further significant RV muscle fibrosis and greater capillary rarefaction. We propose that autophagy inhibition in conjunction with other maladaptive processes reported in the decompensated RV muscle contributes to the genesis of overt RHF in PAH, and that a continuum of changes characterizes the adaptive and maladaptive phases in the RV muscle Keywords: Pulmonary Arterial Hypertension (P

Interplay Between Fatty Acids, Stearoyl-Co-A Desaturase, Mechanistic Target of Rapamycin, and Yes-Associated Protein/Transcriptional Coactivator With PDZ-Binding Motif in Promoting Hepatocellular Carcinoma.

Nonalcoholic fatty liver disease has reached pandemic proportions with one of its most consequential complications being hepatocellular carcinoma (HCC). Nonalcoholic fatty liver disease-related HCC is becoming the leading indication for liver transplantation in the United States. Given the scarcity of available organs, early detection and prevention remain key in prevention and management of the disease. Over the years, the yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) pathway emerged as a key signal transduction pathway in the pathogenesis of HCC. In this review, we explore the interplay between the YAP/TAZ pathway as a point of convergence in HCC pathogenesis. We review the evidence of how lipid reprogramming and key lipid pathways, saturated and monounsaturated fatty acids (through the rate-limiting enzyme stearoyl Co-A desaturase), the mevalonic acid pathway (the role of statins), and mechanistic target of rapamycin all play critical roles in intricate and complex networks that tightly regulate the YAP/TAZ pro-oncogenic pathway.

The Role of Alternative Splicing Factors, DDB2-Related Ageing and DNA Damage Repair in the Progression and Prognosis of Stomach Adenocarcinoma Patients.

DNA damage response is a key signal transduction pathway in triggering ageing and tumor progression. Abnormal alternative splicing (AS) is associated with tumors and ageing. However, the role of AS factors associated with DNA damage repair and ageing in stomach adenocarcinoma (STAD) remains unclear. We downloaded the percentage of splicing (PSI) values for AS in STAD from the TCGA SpliceSeq database. The PSI values of DNA repair gene AS events were integrated with STAD patient survival data for Cox regression analysis. The prediction model for the overall survival (OS) was constructed by the clinical traits. The tumor immune microenvironment was analyzed by CIBERSORT and ESTIMATE. We detected 824 AS events originating from 166 DNA repair genes. Cox regression analysis provided 21 prognostic AS events connected with OS statistically, and a prognostic prediction model was constructed. The expression of these AS factors was higher in STAD tumors. DDB2 high senescence levels were associated with active immune responses and better survival in STAD patients. We built a novel prognostic model founded on DNA repair genes with AS events and identified that DDB2 may be a potential biomarker to apply in clinics.

Aberrant B Cell Signaling in Autoimmune Diseases.

Aberrant B cell signaling plays a critical in role in various systemic and organ-specific autoimmune diseases. This is supported by genetic evidence by many functional studies in B cells from patients or specific animal models and by the observed efficacy of small-molecule inhibitors. In this review, we first discuss key signal transduction pathways downstream of the B cell receptor (BCR) that ensure that autoreactive B cells are removed from the repertoire or functionally silenced. We provide an overview of aberrant BCR signaling that is associated with inappropriate B cell repertoire selection and activation or survival of peripheral B cell populations and plasma cells, finally leading to autoantibody formation. Next to BCR signaling, abnormalities in other signal transduction pathways have been implicated in autoimmune disease. These include reduced activity of several phosphates that are downstream of co-inhibitory receptors on B cells and increased levels of BAFF and APRIL, which support survival of B cells and plasma cells. Importantly, pathogenic synergy of the BCR and Toll-like receptors (TLR), which can be activated by endogenous ligands, such as self-nucleic acids, has been shown to enhance autoimmunity. Finally, we will briefly discuss therapeutic strategies for autoimmune disease based on interfering with signal transduction in B cells.

PKC-mediated phosphorylation and activation of the MEK/ERK pathway as a mechanism of acquired trastuzumab resistance in HER2-positive breast cancer.

Protein expression, activation and stability are regulated through inter-connected signal transduction pathways resulting in specific cellular states. This study sought to differentiate between the complex mechanisms of intrinsic and acquired trastuzumab resistance, by quantifying changes in expression and activity of proteins (phospho-protein profile) in key signal transduction pathways, in breast cancer cellular models of trastuzumab resistance. To this effect, we utilized a multiplex, bead-based protein assay, DigiWest®, to measure around 100 proteins and protein modifications using specific antibodies. The main advantage of this methodology is the quantification of multiple analytes in one sample, utilising input volumes of a normal western blot. The intrinsically trastuzumab-resistant cell line JIMT-1 showed the largest number of concurrent resistance mechanisms, including PI3K/Akt and RAS/RAF/MEK/ERK activation, β catenin stabilization by inhibitory phosphorylation of GSK3β, cell cycle progression by Rb suppression, and CREB-mediated cell survival. MAPK (ERK) pathway activation was common to both intrinsic and acquired resistance cellular models. The overexpression of upstream RAS/RAF, however, was confined to JIMT 1; meanwhile, in a cellular model of acquired trastuzumab resistance generated in this study (T15), entry into the ERK pathway seemed to be mostly mediated by PKCα activation. This is a novel observation and merits further investigation that can lead to new therapeutic combinations in HER2-positive breast cancer with acquired therapeutic resistance.

Key signal transduction pathways and crosstalk in cancer: Biological and therapeutic opportunities

Several different signaling pathways and molecular mechanisms have been identified as responsible for controlling critical functions in human cancer cells, such as selective growth and proliferative advantage, altered stress response favoring overall survival, vascularization, invasion and metastasis, metabolic rewiring, an abetting microenvironment, and immune modulation. This concise summary will provide a selective review of recent studies of key signal transduction pathways, including mitogen-activated protein kinase (MAPK) pathway, Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling, and Wnt/β-catenin signaling pathway, which are altered in cancer cells, as the novel and promising therapeutic targets.

M6A in the Signal Transduction Network.

In response to environmental changes, signaling pathways rewire gene expression programs through transcription factors. Epigenetic modification of the transcribed RNA can be another layer of gene expression regulation. N6-adenosine methylation (m6A) is one of the most common modifications on mRNA. It is a reversible chemical mark catalyzed by the enzymes that deposit and remove methyl groups. m6A recruits effector proteins that determine the fate of mRNAs through changes in splicing, cellular localization, stability, and translation efficiency. Emerging evidence shows that key signal transduction pathways including TGFβ (transforming growth factor-β), ERK (extracellular signal-regulated kinase), and mTORC1 (mechanistic target of rapamycin complex 1) regulate downstream gene expression through m6A processing. Conversely, m6A can modulate the activity of signal transduction networks via m6A modification of signaling pathway genes or by acting as a ligand for receptors. In this review, we discuss the current understanding of the crosstalk between m6A and signaling pathways and its implication for biological systems.

Lipid Metabolism and Cancer.

Lipid metabolism is involved in the regulation of numerous cellular processes, such as cell growth, proliferation, differentiation, survival, apoptosis, inflammation, movement, membrane homeostasis, chemotherapy response, and drug resistance. Reprogramming of lipid metabolism is a typical feature of malignant tumors. In a variety of cancers, fat uptake, storage and fat production are up-regulated, which in turn promotes the rapid growth, invasion, and migration of tumors. This paper systematically summarizes the key signal transduction pathways and molecules of lipid metabolism regulating tumors, and the role of lipid metabolism in programmed cell death. In conclusion, understanding the potential molecular mechanism of lipid metabolism and the functions of different lipid molecules may facilitate elucidating the mechanisms underlying the occurrence of cancer in order to discover new potential targets for the development of effective antitumor drugs.