The dark side of Ras: regulation of apoptosis

Beyond Death: Unmasking the Intricacies of Apoptosis Escape

Apoptosis, or programmed cell death, maintains tissue homeostasis by eliminating damaged or unnecessary cells. However, cells can evade this process, contributing to conditions such as cancer. Escape mechanisms include anoikis, mitochondrial DNA depletion, cellular FLICE inhibitory protein (c-FLIP), endosomal sorting complexes required for transport (ESCRT), mitotic slippage, anastasis, and blebbishield formation. Anoikis, triggered by cell detachment from the extracellular matrix, is pivotal in cancer research due to its role in cellular survival and metastasis. Mitochondrial DNA depletion, associated with cellular dysfunction and diseases such as breast and prostate cancer, links to apoptosis resistance. The c-FLIP protein family, notably CFLAR, regulates cell death processes as a truncated caspase-8 form. The ESCRT complex aids apoptosis evasion by repairing intracellular damage through increased Ca2+ levels. Antimitotic agents induce mitotic arrest in cancer treatment but can lead to mitotic slippage and tetraploid cell formation. Anastasis allows cells to resist apoptosis induced by various triggers. Blebbishield formation suppresses apoptosis indirectly in cancer stem cells by transforming apoptotic cells into blebbishields. In conclusion, the future of apoptosis research offers exciting possibilities for innovative therapeutic approaches, enhanced diagnostic tools, and a deeper understanding of the complex biological processes that govern cell fate. Collaborative efforts across disciplines, including molecular biology, genetics, immunology, and bioinformatics, will be essential to realize these prospects and improve patient outcomes in diverse disease contexts.

Signaling pathways in liver cancer: pathogenesis and targeted therapy

Liver cancer remains one of the most prevalent malignancies worldwide with high incidence and mortality rates. Due to its subtle onset, liver cancer is commonly diagnosed at a late stage when surgical interventions are no longer feasible. This situation highlights the critical role of systemic treatments, including targeted therapies, in bettering patient outcomes. Despite numerous studies on the mechanisms underlying liver cancer, tyrosine kinase inhibitors (TKIs) are the only widely used clinical inhibitors, represented by sorafenib, whose clinical application is greatly limited by the phenomenon of drug resistance. Here we show an in-depth discussion of the signaling pathways frequently implicated in liver cancer pathogenesis and the inhibitors targeting these pathways under investigation or already in use in the management of advanced liver cancer. We elucidate the oncogenic roles of these pathways in liver cancer especially hepatocellular carcinoma (HCC), as well as the current state of research on inhibitors respectively. Given that TKIs represent the sole class of targeted therapeutics for liver cancer employed in clinical practice, we have particularly focused on TKIs and the mechanisms of the commonly encountered phenomena of its resistance during HCC treatment. This necessitates the imperative development of innovative targeted strategies and the urgency of overcoming the existing limitations. This review endeavors to shed light on the utilization of targeted therapy in advanced liver cancer, with a vision to improve the unsatisfactory prognostic outlook for those patients.

Targeting the EGFR/RAS/RAF signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023)

INTRODUCTION

Recent years have seen significant strides in drug developmenttargeting the EGFR/RAS/RAF signaling pathway which is critical forcell growth and proliferation. Protein-protein interaction networksamong EGFR, RAS, and RAF proteins offer insights for drug discovery. This review discusses the drug design and development efforts ofinhibitors targeting these proteins over the past 3 years, detailingtheir structures, selectivity, efficacy, and combination therapy.Strategies to combat drug resistance and minimize toxicities areexplored, along with future research directions.

AREA COVERED

This review encompasses clinical trials and patents on EGFR, KRAS,and BRAF inhibitors from 2020 to 2023, including advancements indesign and synthesis of proteolysis targeting chimeras (PROTACs) forprotein degradation.

EXPERT OPINION

To tackle drug resistance, designing allosteric fourth-generationEGFR inhibitors is vital. Covalent, allosteric, or combinationaltherapies, along with PROTAC degraders, are key methods to addressresistance and toxicity in KRAS and BRAF inhibitors.

Skin treatment with non-thermal plasma modulates the immune system through miR-223-3p and its target genes

Non-thermal plasma, a partially ionized gas, holds significant potential for clinical applications, including wound-healing support, oral therapies, and anti-tumour treatments. While its applications showed promising outcomes, the underlying molecular mechanisms remain incompletely understood. We thus apply non-thermal plasma to mouse auricular skin and conducted non-coding RNA sequencing, as well as single-cell blood sequencing. In a time-series analysis (five timepoints spanning 2 hours), we compare the expression of microRNAs in the plasma-treated left ears to the unexposed right ears of the same mice as well as to the ears of unexposed control mice. Our findings indicate specific effects in the treated ears for a set of five miRNAs: mmu-miR-144-5p, mmu-miR-144-3p, mmu-miR-142a-5p, mmu-miR-223-3p, and mmu-miR-451a. Interestingly, mmu-miR-223-3p also exhibits an increase over time in the right non-treated ear of the exposed mice, suggesting systemic effects. Notably, this miRNA, along with mmu-miR-142a-5p and mmu-miR-144-3p, regulates genes and pathways associated with wound healing and tissue regeneration (namely ErbB, FoxO, Hippo, and PI3K-Akt signalling). This co-regulation is particularly remarkable considering the significant seed dissimilarities among the miRNAs. Finally, single-cell sequencing of PBMCs reveals the downregulation of 12 from 15 target genes in B-cells, Cd4+ and Cd8+ T-cells. Collectively, our data provide evidence for a systemic effect of non-thermal plasma.

The whole blood DNA methylation of RAB8A and RAP1A in autoimmune thyroiditis: evidence and validation of iodine exposure in a population from different water iodine areas

Our study aimed to identify and verify G protein-related methylated genes in AIT patients, while also investigate those genes in AIT patients exposed to iodine in different water iodine areas. Different areas were classified by median water iodine (MWI) concentrations: Iodine-Fortified Areas (IFA, MWI<10µg/L), Iodine-Adequate Areas (IAA, 40≤MWI≤100 µg/L), and Iodine-Excessive Areas (IEA, MWI>100 µg/L). We studied 176 AIT cases and 176 controls, with 89, 40, and 47 pairs in IFA, IAA, and IEA, respectively. Using the Illumina Human Methylation 850k BeadChip, we identified candidate methylated genes. MethylTargetTM and QRT-PCR validated DNA methylation and mRNA expression. Results showed hypomethylation and high expression of RAB8A and RAP1A in all 176 AIT cases. RAB8A's CpG sites were mainly hypomethylated in IFA and IEA, while RAP1A's sites were primarily hypomethylated in IEA. This study underscores how water iodine exposure may influence RAB8A and RAP1A methylation in AIT.

CD40 induces selective routing of Ras isoforms to subcellular compartments

Ras GTPases are central to cellular signaling and oncogenesis. The three loci of the Ras gene encode for four protein isoforms namely Harvey-Ras (H-Ras), Kirsten-Ras (K-Ras 4A and 4B), and Neuroblastoma-Ras (N-Ras) which share ~ 80% sequence similarity and used to be considered functionally redundant. The small molecule inhibitors of Ras lack specificity for the isoforms leading to widespread toxicity in Ras-targeted therapeutics. Ras isoforms' tissue-specific expression and selective association with carcinogenesis, embryonic development, and infection suggested their non-redundancy. We show that CD40, an antigen-presenting cell (APC)-expressed immune receptor, induces selective relocation of H-Ras, K-Ras, and N-Ras to the Plasma membrane (PM) lipid rafts, mitochondria, endoplasmic reticulum (ER), but not to the Golgi complex (GC). The two palmitoylated Ras isoforms-H-Ras and N-Ras-have a similar pattern of colocalization into the lipid-rich raft microdomain of the PM at early time points when compared to non-palmitoylated K-Ras (4B) with polylysine residues. CD40-induced trafficking of H-Ras and K-Ras to mitochondria and ER was found to be similar but different from that of N-Ras. Trafficking of all the Ras isoforms to the GC was independent of CD40 stimulation. The receptor-driven trafficking and spatial segregation of H-Ras, K-Ras, and N-Ras imply isoform-specific subcellular signaling platforms for the functional non-redundancy of Ras isoforms. PDB structures have been modified to illustrate various signaling proteins.

A New Insight into 6-Pentyl-2H-pyran-2-one against Peronophythora litchii via TOR Pathway

The litchi downy blight disease of litchi caused by Peronophythora litchii accounts for severe losses in the field and during storage. While ample quantitative studies have shown that 6-pentyl-2H-pyran-2-one (6PP) possesses antifungal activities against multiple plant pathogenic fungi, the regulatory mechanisms of 6PP-mediated inhibition of fungal pathogenesis and growth are still unknown. Here, we investigated the potential molecular targets of 6PP in the phytopathogenic oomycetes P. litchii through integrated deployment of RNA-sequencing, functional genetics, and biochemical techniques to investigate the regulatory effects of 6PP against P. litchii. Previously we demonstrated that 6PP exerted significant oomyticidal activities. Also, comparative transcriptomic evaluation of P. litchii strains treated with 6PP Revealed significant up-regulations in the expression profile of TOR pathway-related genes, including PlCytochrome C and the transcription factors PlYY1. We also noticed that 6PP treatment down-regulated putative negative regulatory genes of the TOR pathway, including PlSpm1 and PlrhoH12 in P. litchii. Protein-ligand binding analyses revealed stable affinities between PlYY1, PlCytochrome C, PlSpm1, PlrhoH12 proteins, and the 6PP ligand. Phenotypic characterization of PlYY1 targeted gene deletion strains generated in this study using CRISPR/Cas9 and homologous recombination strategies significantly reduced the vegetative growth, sporangium, encystment, zoospore release, and pathogenicity of P. litchii. These findings suggest that 6PP-mediated activation of PlYY1 expression positively regulates TOR-related responses and significantly influences vegetative growth and the virulence of P. litchii. The current investigations revealed novel targets for 6PP and underscored the potential of deploying 6PP in developing management strategies for controlling the litchi downy blight pathogen.

Proteomic Mapping of the Interactome of KRAS Mutants Identifies New Features of RAS Signalling Networks and the Mechanism of Action of Sotorasib

RAS proteins are key regulators of cell signalling and control different cell functions including cell proliferation, differentiation, and cell death. Point mutations in the genes of this family are common, particularly in KRAS. These mutations were thought to cause the constitutive activation of KRAS, but recent findings showed that some mutants can cycle between active and inactive states. This observation, together with the development of covalent KRASG12C inhibitors, has led to the arrival of KRAS inhibitors in the clinic. However, most patients develop resistance to these targeted therapies, and we lack effective treatments for other KRAS mutants. To accelerate the development of RAS targeting therapies, we need to fully characterise the molecular mechanisms governing KRAS signalling networks and determine what differentiates the signalling downstream of the KRAS mutants. Here we have used affinity purification mass-spectrometry proteomics to characterise the interactome of KRAS wild-type and three KRAS mutants. Bioinformatic analysis associated with experimental validation allows us to map the signalling network mediated by the different KRAS proteins. Using this approach, we characterised how the interactome of KRAS wild-type and mutants is regulated by the clinically approved KRASG12C inhibitor Sotorasib. In addition, we identified novel crosstalks between KRAS and its effector pathways including the AKT and JAK-STAT signalling modules.

HRas and Myc synergistically induce cell cycle progression and apoptosis of murine cardiomyocytes

Aim

Adult mammalian cardiomyocytes are incapable of significant proliferation, limiting regeneration after myocardial injury. Overexpression of the transcription factor Myc has been shown to drive proliferation in the adult mouse heart, but only when combined with Cyclin T1. As constitutive HRas activity has been shown to stabilise Cyclin T1 in vivo, we aimed to establish whether Myc and HRas could also act cooperatively to induce proliferation in adult mammalian cardiomyocytes in vivo.

Methods and results

Using a genetically modified mouse model, we confirmed that constitutive HRas activity (HRas G 12 V ) increased Cyclin T1 expression. HRas G 12 V and constitutive Myc expression together co-operate to drive cell-cycle progression of adult mammalian cardiomyocytes. However, stimulation of endogenous cardiac proliferation by the ectopic expression of HRas G 12 V and Myc also induced cardiomyocyte death, while Myc and Cyclin T1 expression did not.

Conclusion

Co-expression of Cyclin T1 and Myc may be a therapeutically tractable approach for cardiomyocyte neo-genesis post injury, while cell death induced by HRas G 12 V and Myc expression likely limits this option as a regenerative therapeutic target.

Proteomics on the role of muscone in the "consciousness-restoring resuscitation" effect of musk on ischemic stroke

ETHNOPHARMACOLOGICAL RELEVANCE

Musk is a representative drug of aroma-relieving traditional Chinese medicine, and it is a commonly used traditional Chinese medicine for the treatment of ischemic stroke. Muscone is the core medicinal component of musk.

AIM OF THE STUDY

We sought to identify the target of muscone in the treatment of ischemic stroke using network pharmacology, an animal model of ischemic stroke, and differential proteomics.

MATERIALS AND METHODS

The drug targets of muscone in the treatment of ischemic stroke were predicted and analyzed using information derived from sources such as the Traditional Chinese Medicine Systems Pharmacology database and Swiss Target Prediction tool. The animal model of focal cerebral ischemia was established by suture-based occlusion of the middle cerebral artery of rats. The rats were divided into six groups: sham-operated control, model, musk, muscone1, muscone2, and muscone3. Neurological deficit scores were calculated after intragastric administration of musk or muscone. The microcirculation blood flow of the pia mater was detected using a laser speckle blood flow meter. The cerebral infarction rate was detected by 2,3,5-triphenyltetrazolium chloride staining. The necrosis rate of the cerebral cortex and the hippocampal neurons was detected by hematoxylin and eosin staining. Blood-brain barrier damage was detected by the Evans blue method. Quantitative proteomics analysis in the sham-operated control, model, and muscone groups was performed using tandem-mass-tags. Considering fold changes exceeding 1.2 as differential protein expression, the quantitative values were compared among groups by analysis of variance. Furthermore, a protein-protein interaction network was constructed, and differentially expressed proteins were analyzed by gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis.

RESULTS

Network pharmacology identified 339 targets for the intersection of 17 components of musk and cerebral ischemia-reperfusion injury. The GO and KEGG enrichment items mainly identified regulation of neuronal synaptic structure and transfer function, synaptic neurotransmitters, and receptor activity. Zoopery showed that the model group had a higher behavioral score, cerebral infarction rate, cortical and hippocampal neuron death rate, Evans blue exudation in the brain, and bilateral pia mater microcirculation blood flow differences than the sham-operated control group (P <0.01). Compared with the model group, the behavioral score, infarction rate, hippocampal neuronal mortality, and Evans blue content decreased significantly in the musk, muscone2, and muscone3 groups (P <0.05). Proteomic analysis showed that 160 genes were differentially expressed among the sham-operated control, model, and muscone groups. GO items with high enrichment included neuronal synapses, postsynaptic signal transduction, etc. KEGG items with high enrichment included cholinergic synapses, calcium signaling pathway, dopaminergic synapses, etc. Protein interaction analysis revealed that the top three protein pairs were Ndufa10/Ndufa6, Kcna2/Kcnab2, and Gsk3b/Traf6.

CONCLUSIONS

Muscone can reduce neuronal necrosis, protect the blood-brain barrier, and improve the neurological damage caused by cerebral ischemia via molecular mechanisms mainly involving the regulation of neuronal synaptic connections. Muscone is an important active component responsible for the "consciousness-restoring resuscitation" effect of musk on ischemic stroke.

RAS oncogenic activity predicts response to chemotherapy and outcome in lung adenocarcinoma

Activating mutations in KRAS occur in 32% of lung adenocarcinomas (LUAD). Despite leading to aggressive disease and resistance to therapy in preclinical studies, the KRAS mutation does not predict patient outcome or response to treatment, presumably due to additional events modulating RAS pathways. To obtain a broader measure of RAS pathway activation, we developed RAS84, a transcriptional signature optimised to capture RAS oncogenic activity in LUAD. We report evidence of RAS pathway oncogenic activation in 84% of LUAD, including 65% KRAS wild-type tumours, falling into four groups characterised by coincident alteration of STK11/LKB1, TP53 or CDKN2A, suggesting that the classifications developed when considering only KRAS mutant tumours have significance in a broader cohort of patients. Critically, high RAS activity patient groups show adverse clinical outcome and reduced response to chemotherapy. Patient stratification using oncogenic RAS transcriptional activity instead of genetic alterations could ultimately assist in clinical decision-making.

Analysis of Protein-Protein Interactions for Intermolecular Bond Prediction

Protein-protein interactions often involve a complex system of intermolecular interactions between residues and atoms at the binding site. A comprehensive exploration of these interactions can help reveal key residues involved in protein-protein recognition that are not obvious using other protein analysis techniques. This paper presents and extends DiffBond, a novel method for identifying and classifying intermolecular bonds while applying standard definitions of bonds in chemical literature to explain protein interactions. DiffBond predicted intermolecular bonds from four protein complexes: Barnase-Barstar, Rap1a-raf, SMAD2-SMAD4, and a subset of complexes formed from three-finger toxins and nAChRs. Based on validation through manual literature search and through comparison of two protein complexes from the SKEMPI dataset, DiffBond was able to identify intermolecular ionic bonds and hydrogen bonds with high precision and recall, and identify salt bridges with high precision. DiffBond predictions on bond existence were also strongly correlated with observations of Gibbs free energy change and electrostatic complementarity in mutational experiments. DiffBond can be a powerful tool for predicting and characterizing influential residues in protein-protein interactions, and its predictions can support research in mutational experiments and drug design.

Crucial Role of Oncogenic KRAS Mutations in Apoptosis and Autophagy Regulation: Therapeutic Implications

KRAS, one of the RAS protein family members, plays an important role in autophagy and apoptosis, through the regulation of several downstream effectors. In cancer cells, KRAS mutations confer the constitutive activation of this oncogene, stimulating cell proliferation, inducing autophagy, suppressing apoptosis, altering cell metabolism, changing cell motility and invasion and modulating the tumor microenvironment. In order to inhibit apoptosis, these oncogenic mutations were reported to upregulate anti-apoptotic proteins, including Bcl-xL and survivin, and to downregulate proteins related to apoptosis induction, including thymine-DNA glycosylase (TDG) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). In addition, KRAS mutations are known to induce autophagy in order to promote cell survival and tumor progression through MAPK and PI3K regulation. Thus, these mutations confer resistance to anti-cancer drug treatment and, consequently, result in poor prognosis. Several therapies have been developed in order to overcome KRAS-induced cell death resistance and the downstream signaling pathways blockade, especially by combining MAPK and PI3K inhibitors, which demonstrated promising results. Understanding the involvement of KRAS mutations in apoptosis and autophagy regulation, might bring new avenues to the discovery of therapeutic approaches for CRCs harboring KRAS mutations.

Integrins Cooperate With the EGFR/Ras Pathway to Preserve Epithelia Survival and Architecture in Development and Oncogenesis

Adhesion to the extracellular matrix (ECM) is required for normal epithelial cell survival. Disruption of this interaction leads to a specific type of apoptosis known as anoikis. Yet, there are physiological and pathological situations in which cells not connected to the ECM are protected from anoikis, such as during cell migration or metastasis. The main receptors transmitting signals from the ECM are members of the integrin family. However, although integrin-mediated cell-ECM anchorage has been long recognized as crucial for epithelial cell survival, the in vivo significance of this interaction remains to be weighed. In this work, we have used the Drosophila wing imaginal disc epithelium to analyze the importance of integrins as survival factors during epithelia morphogenesis. We show that reducing integrin expression in the wing disc induces caspase-dependent cell death and basal extrusion of the dead cells. In this case, anoikis is mediated by the activation of the JNK pathway, which in turn triggers expression of the proapoptotic protein Hid. In addition, our results strongly suggest that, during wing disc morphogenesis, the EGFR pathway protects cells undergoing cell shape changes upon ECM detachment from anoikis. Furthermore, we show that oncogenic activation of the EGFR/Ras pathway in integrin mutant cells rescues them from apoptosis while promoting their extrusion from the epithelium. Altogether, our results support the idea that integrins promote cell survival during normal tissue morphogenesis and prevent the extrusion of transformed cells.

Effects of NRAS Mutations on Leukemogenesis and Targeting of Children With Acute Lymphoblastic Leukemia

Through the advancements in recent decades, childhood acute lymphoblastic leukemia (ALL) is gradually becoming a highly curable disease. However, the truth is there remaining relapse in ∼15% of ALL cases with dismal outcomes. RAS mutations, in particular NRAS mutations, were predominant mutations affecting relapse susceptibility. KRAS mutations targeting has been successfully exploited, while NRAS mutation targeting remains to be explored due to its complicated and compensatory mechanisms. Using targeted sequencing, we profiled RAS mutations in 333 primary and 18 relapsed ALL patients and examined their impact on ALL leukemogenesis, therapeutic potential, and treatment outcome. Cumulative analysis showed that RAS mutations were associated with a higher relapse incidence in children with ALL. In vitro cellular assays revealed that about one-third of the NRAS mutations significantly transformed Ba/F3 cells as measured by IL3-independent growth. Meanwhile, we applied a high-throughput drug screening method to characterize variable mutation-related candidate targeted agents and uncovered that leukemogenic-NRAS mutations might respond to MEK, autophagy, Akt, EGFR signaling, Polo−like Kinase, Src signaling, and TGF−β receptor inhibition depending on the mutation profile.

Proliferation and Apoptosis Pathways and Factors in Oral Squamous Cell Carcinoma

Oral cancer is the most common form of head and neck squamous cell carcinoma (HNSCC) and most frequently presents as oral squamous cell carcinoma (OSCC), which is associated with an alarmingly high mortality rate. Internationally, a plethora of research to further our understanding of the molecular pathways related to oral cancer is performed. This research is of value for early diagnosis, prognosis, and the investigation of new drugs that can ameliorate the harmful effects of oral cancer and provide optimal patient outcomes with minimal long-term complications. Two pathways on which the progression of OSCC depends on are those of proliferation and apoptosis, which overlap at many junctions. Herein, we aim to review these pathways and factors related to OSCC progression. Publicly available search engines, PubMed and Google Scholar, were used with the following keywords to identify relevant literature: oral cancer, proliferation, proliferation factors, genes, mutations, and tumor suppressor. We anticipate that the use of information provided through this review will further progress translational cancer research work in the field of oral cancer.

Interleukin-1 signaling in solid organ malignancies

As inflammation plays a critical role in the development and progression of cancer, therapeutic targeting of cytokine pathways involved in both tumorigenesis and dictating response to clinical treatments are of significant interest. Recent evidence has highlighted the importance of the pro-inflammatory cytokine interleukin-1 (IL-1) as a key mediator of tumor growth, metastatic disease spread, immunosuppression, and drug resistance in cancer. IL-1 promotes tumorigenesis through diverse mechanisms, including the activation of oncogenic signaling pathways directly in tumor cells and via orchestrating crosstalk between the cellular constituents of the tumor microenvironment (TME), thereby driving cancer growth. This review will provide an overview of IL-1 signaling and physiology and summarize the disparate mechanisms involving IL-1 in tumorigenesis and cancer progression. Additionally, clinical studies targeting IL-1 signaling in the management of solid organ tumors will be summarized herein.

DiffBond: A Method for Predicting Intermolecular Bond Formation

Many tools that explore models of protein complexes are also able to analyze interactions between specific residues and atoms. A comprehensive exploration of these interactions can often uncover aspects of protein-protein recognition that are not obvious using other protein analysis techniques. This paper describes DiffBond, a novel method for searching for intermolecular interactions between protein complexes while differentiating between three different types of interaction: hydrogen bonds, ionic bonds, and salt bridges. DiffBond incorporates textbook definitions of these three interactions while contending with uncertainties that are inherent in computational models of interacting proteins. We used it to examine the barnase-barstar, Rap1a-raf, and Smad2-Smad4 complexes, as well as a subset of protein complexes formed between three-finger toxins and nAChRs. Based on electrostatic interactions established by previous experimental studies, DiffBond was able to identify ionic and hydrogen bonds with high precision and recall, and identify salt bridges with high precision. In combination with other electrostatic analysis methods, DiffBond can be a useful tool in helping predict influential amino acids in protein-protein interactions and characterizing the type of interaction.

Pan-RAS inhibitors: Hitting multiple RAS isozymes with one stone

Mutations in the three RAS oncogenes are present in approximately 30% of all human cancers that drive tumor growth and metastasis by aberrant activation of RAS-mediated signaling. Despite the well-established role of RAS in tumorigenesis, past efforts to develop small molecule inhibitors have failed for various reasons leading many to consider RAS as "undruggable." Advances over the past decade with KRAS(G12C) mutation-specific inhibitors have culminated in the first FDA-approved RAS drug, sotorasib. However, the patient population that stands to benefit from KRAS(G12C) inhibitors is inherently limited to those patients harboring KRAS(G12C) mutations. Additionally, both intrinsic and acquired mechanisms of resistance have been reported that indicate allele-specificity may afford disadvantages. For example, the compensatory activation of uninhibited wild-type (WT) NRAS and HRAS isozymes can rescue cancer cells harboring KRAS(G12C) mutations from allele-specific inhibition or the occurrence of other mutations in KRAS. It is therefore prudent to consider alternative drug discovery strategies that may overcome these potential limitations. One such approach is pan-RAS inhibition, whereby all RAS isozymes co-expressed in the tumor cell population are targeted by a single inhibitor to block constitutively activated RAS regardless of the underlying mutation. This chapter provides a review of past and ongoing strategies to develop pan-RAS inhibitors in detail and seeks to outline the trajectory of this promising strategy of RAS inhibition.

KRASG12C inhibitor: combing for combination

Oncogenic mutation in KRAS is one of the most common alterations in human cancer. After decades of extensive research and unsuccessful drug discovery programs, therapeutic targeting of KRAS mutant tumour is at an exciting juncture. The discovery of mutation-specific inhibitors of KRASG12C and early positive findings from clinical trials has raised the hope of finally having a drug to treat a significant segment of KRAS mutant cancer patients. Crucially, it has also re-energized the RAS field to look beyond G12C mutation and find new innovative targeting opportunities. However, the early clinical trial data also indicates that there is significant variation in response among patients and that monotherapy treatment with KRASG12C inhibitors (G12Ci) alone is unlikely to be sufficient to elicit a sustained response. Understanding the molecular mechanism of variation in patient response and identifying possible combination opportunities, which could be exploited to achieve durable and significant responses and delay emergence of resistance, is central to the success of G12Ci therapy. Given the specificity of G12Ci, toxicity is expected to be minimal. Therefore, it might be possible to combine G12Ci with other targeted agents which have previously been explored to tackle KRAS mutant cancer but deemed too toxic, e.g. MEK inhibitor. Ongoing clinical trials will shed light on clinical resistance to G12C inhibitors, however extensive work is already ongoing to identify the best combination partners. This review provides an update on combination opportunities which could be explored to maximize the benefit of this new exciting drug.

The Importance of Being PI3K in the RAS Signaling Network

Ras proteins are essential mediators of a multitude of cellular processes, and its deregulation is frequently associated with cancer appearance, progression, and metastasis. Ras-driven cancers are usually aggressive and difficult to treat. Although the recent Food and Drug Administration (FDA) approval of the first Ras G12C inhibitor is an important milestone, only a small percentage of patients will benefit from it. A better understanding of the context in which Ras operates in different tumor types and the outcomes mediated by each effector pathway may help to identify additional strategies and targets to treat Ras-driven tumors. Evidence emerging in recent years suggests that both oncogenic Ras signaling in tumor cells and non-oncogenic Ras signaling in stromal cells play an essential role in cancer. PI3K is one of the main Ras effectors, regulating important cellular processes such as cell viability or resistance to therapy or angiogenesis upon oncogenic Ras activation. In this review, we will summarize recent advances in the understanding of Ras-dependent activation of PI3K both in physiological conditions and cancer, with a focus on how this signaling pathway contributes to the formation of a tumor stroma that promotes tumor cell proliferation, migration, and spread.

The effect of microbial composition and proteomic on improvement of functional constipation by Chrysanthemum morifolium polysaccharide

In this paper, SD rat constipation model was established with loperamide hydrochloride to study the effect of Chrysanthemum morifolium polysaccharide on the improvement of functional constipation, and the mechanism of improving constipation was investigated with the proteomics and intestinal flora. The results showed that the HD group of C. morifolium polysaccharide could significantly increase the levels of water content of stool pellets, small intestine propulsion rate, gastrin (MTL), gastrin (GAS) and substance P (SP), decrease the level of growth inhibitor (SS) and improved gastrointestinal motility in rats. Gut microbial studies showed that C. morifolium polysaccharide could significantly increase species abundance and flora diversity and improve flora structure. The relative abundance of Lactobacillus and Romboutsia increased, while the relative abundance of Lachnospiraceae_NK4A136_group and Roseburia decreased compared with the MC group. Proteomics studies suggested that C. morifolium polysaccharides could reduce intestinal lesions, enhance intestinal homeostasis, increase amino acid uptake, promote intestinal motility and relieve constipation by regulating the expression of RAS, FABP1 and SLC1A5 proteins.

Ras Isoforms from Lab Benches to Lives-What Are We Missing and How Far Are We?

The central protein in the oncogenic circuitry is the Ras GTPase that has been under intense scrutiny for the last four decades. From its discovery as a viral oncogene and its non-oncogenic contribution to crucial cellular functioning, an elaborate genetic, structural, and functional map of Ras is being created for its therapeutic targeting. Despite decades of research, there still exist lacunae in our understanding of Ras. The complexity of the Ras functioning is further exemplified by the fact that the three canonical Ras genes encode for four protein isoforms (H-Ras, K-Ras4A, K-Ras4B, and N-Ras). Contrary to the initial assessment that the H-, K-, and N-Ras isoforms are functionally similar, emerging data are uncovering crucial differences between them. These Ras isoforms exhibit not only cell-type and context-dependent functions but also activator and effector specificities on activation by the same receptor. Preferential localization of H-, K-, and N-Ras in different microdomains of the plasma membrane and cellular organelles like Golgi, endoplasmic reticulum, mitochondria, and endosome adds a new dimension to isoform-specific signaling and diverse functions. Herein, we review isoform-specific properties of Ras GTPase and highlight the importance of considering these towards generating effective isoform-specific therapies in the future.

Stem cells and origins of cancer in the upper gastrointestinal tract

The esophagus and stomach, joined by a unique transitional zone, contain actively dividing epithelial stem cells required for organ homeostasis. Upon prolonged inflammation, epithelial cells in both organs can undergo a cell fate switch leading to intestinal metaplasia, predisposing to malignancy. Here we discuss the biology of gastroesophageal stem cells and their role as cells of origin in cancer. We summarize the interactions between the stromal niche and gastroesophageal stem cells in metaplasia and early expansion of mutated stem-cell-derived clones during carcinogenesis. Finally, we review new approaches under development to better study gastroesophageal stem cells and advance the field.

Role of ARK5 in cancer and other diseases (Review)

Malignant tumors are often exposed to hypoxic and glucose-starved microenvironments. AMP-activated protein kinase (AMPK) is an energy sensor that is stimulated during energy-deficient conditions and protects cells from hypoxic injury by regulating metabolism. AMPK-related protein kinase 5 (ARK5) is a member of the catalytic sub-unit of the AMPK family and has an important role in energy regulation and hypoxia. ARK5 is regulated by Akt and liver kinase B1 and is associated with numerous tumor-related molecules to exert the negative effects of tumors. Studies have revealed ARK5 overexpression in cases of tumor invasion and metastasis and a positive association with the degree of cancer cell malignancy, which is regarded as a key element in determining cancer prognosis. Furthermore, ARK5 downregulation improves drug sensitivity through the epithelial-mesenchymal transition pathway, indicating that it may be a potential therapeutic target. In other non-cancer conditions, ARK5 has various roles in neurodegenerative diseases (Alzheimer's and Huntington's disease), renal disorders (diabetic nephropathy and renal fibrosis) and physiological processes (striated muscle generation). In the present review, the upstream and downstream molecular pathways of ARK5 in cancer and other diseases are described and potential therapeutic strategies are discussed.

Hidden Targets in RAF Signalling Pathways to Block Oncogenic RAS Signalling

Oncogenic RAS (Rat sarcoma) mutations drive more than half of human cancers, and RAS inhibition is the holy grail of oncology. Thirty years of relentless efforts and harsh disappointments have taught us about the intricacies of oncogenic RAS signalling that allow us to now get a pharmacological grip on this elusive protein. The inhibition of effector pathways, such as the RAF-MEK-ERK pathway, has largely proven disappointing. Thus far, most of these efforts were aimed at blocking the activation of ERK. Here, we discuss RAF-dependent pathways that are regulated through RAF functions independent of catalytic activity and their potential role as targets to block oncogenic RAS signalling. We focus on the now well documented roles of RAF kinase-independent functions in apoptosis, cell cycle progression and cell migration.

A Historic Perspective and Overview of H-Ras Structure, Oncogenicity, and Targeting

H-Ras is a unique isoform of the Ras GTPase family, one of the most prominently mutated oncogene families across the cancer landscape. Relative to other isoforms, though, mutations of H-Ras account for the smallest proportion of mutant Ras cancers. Yet, in recent years, there have been renewed efforts to study this isoform, especially as certain H-Ras-driven cancers, like those of the head and neck, have become more prominent. Important advances have therefore been made not only in the understanding of H-Ras structural biology but also in approaches designed to inhibit and impair its signaling activity. In this review, we outline historic and present initiatives to elucidate the mechanisms of H-Ras-dependent tumorigenesis as well as highlight ongoing developments in the quest to target this critical oncogene.

Quantitative Proteomic Analysis in Alveolar Type II Cells Reveals the Different Capacities of RAS and TGF-β to Induce Epithelial-Mesenchymal Transition

Alveolar type II (ATII) epithelial cells function as stem cells, contributing to alveolar renewal, repair and cancer. Therefore, they are a highly relevant model for studying a number of lung diseases, including acute injury, fibrosis and cancer, in which signals transduced by RAS and transforming growth factor (TGF)-β play critical roles. To identify downstream molecular events following RAS and/or TGF-β activation, we performed proteomic analysis using a quantitative label-free approach (LC-HDMS^E) to provide in-depth proteome coverage and estimates of protein concentration in absolute amounts. Data are available via ProteomeXchange with identifier PXD023720. We chose ATII^ER:KRASV12 as an experimental cell line in which RAS is activated by adding 4-hydroxytamoxifen (4-OHT). Proteomic analysis of ATII cells treated with 4-OHT or TGF-β demonstrated that RAS activation induces an epithelial–mesenchymal transition (EMT) signature. In contrast, under the same conditions, activation of TGF-β signaling alone only induces a partial EMT. EMT is a dynamic and reversible biological process by which epithelial cells lose their cell polarity and down-regulate cadherin-mediated cell–cell adhesion to gain migratory properties, and is involved in embryonic development, wound healing, fibrosis and cancer metastasis. Thus, these results could help to focus research on the identification of processes that are potentially driving EMT-related human disease.

Autophagy buffers Ras-induced genotoxic stress enabling malignant transformation in keratinocytes primed by human papillomavirus

Malignant transformation involves an orchestrated rearrangement of cell cycle regulation mechanisms that must balance autonomic mitogenic impulses and deleterious oncogenic stress. Human papillomavirus (HPV) infection is highly prevalent in populations around the globe, whereas the incidence of cervical cancer is 0.15%. Since HPV infection primes cervical keratinocytes to undergo malignant transformation, we can assume that the balance between transforming mitogenic signals and oncogenic stress is rarely attained. We showed that highly transforming mitogenic signals triggered by HRasG12V activity in E6E7-HPV-keratinocytes generate strong replication and oxidative stresses. These stresses are counteracted by autophagy induction that buffers the rapid increase of ROS that is the main cause of genotoxic stress promoted by the oncoprotein. As a result, autophagy creates a narrow window of opportunity for malignant keratinocytes to emerge. This work shows that autophagy is crucial to allow the transition of E6E7 keratinocytes from an immortalized to a malignant state caused by HRasG12V.

Detection of Endogenous RASSF1A Interacting Proteins

RASSF1A is a Ras effector that promotes the anti-proliferative properties of Ras. It acts as a scaffold protein that regulates several pro-apoptotic signaling pathways, thereby linking Ras to their regulation. However, accumulating evidence suggests that RASSF1A functions as a regulator of other additional biological processes, such as DNA repair and transcription, thereby implicating Ras in the modulation of these biological processes. The mechanisms by which RASSF1A modulates these processes is not fully understood but likely involves interacting with other effectors associated with these functions and coordinating their activity. Thus, to fully understand how RASSF1A manifests its activity, it is critical to identify RASSF1A interacting partners.Unfortunately, the reagents available for the detection of RASSF1A are of poor quality and also exhibit low sensitivity. Here we describe an immunoprecipitation protocol, taking into consideration the limitations of currently available reagents, that can reliably detect the endogenous interaction between RASSF1A and its binding partners.

Ras Signaling in Breast Cancer

Ras proteins mediate extracellular and cytoplasmic signaling networks via receptor tyrosine kinase. The Ras pathway induces activation of signaling molecules involved in cell proliferation and growth, cell survival and apoptosis, metabolism, and motility. Although Ras mutations in breast cancer are not frequently reported, hyperactivation of Ras signaling plays an important role in breast cancer growth and progression. Oncogenic Ras activation occurs via loss of Ras GTPase-activating proteins, overexpression of growth factor receptor, and stimulation by various cytokines. Effective control of oncogenic Ras is one of the therapeutic strategies in breast cancer. The mechanisms of intracellular localization, activation, and signaling pathway of Ras in cancer have been used to develop therapeutic candidates. Recent studies have reported an effective therapy for breast cancer by inhibition of enzymes involved in the posttranslational modification of Ras, such as farnesyltransferase and geranylgeranyltransferase 1, and anti-cancer therapies targeting the epidermal growth factor receptor (EGFR). Emerging targets involved in EGF-mediated Ras activity in breast cancer have shed new insight into Ras activation in breast cancer progression. These alternative mechanisms for Ras signaling pathway may suggest novel therapeutic approaches for targeting Ras in breast cancer. In spite of the difficulties in targeting Ras protein, important discoveries highlight the direct inhibition of Ras activity. Further studies may elucidate the effects of targeting Ras protein and the clinical relevance thereof.

The RASSF1A Tumor Suppressor Binds the RasGAP DAB2IP and Modulates RAS Activation in Lung Cancer

Simple Summary

The RASSF1A tumor suppressor can serve as a pro-apoptotic effector of the K-RAS oncoprotein. It is frequently inactivated epigenetically in lung cancer, and genetic inactivation of RASSF1A in transgenic mice enhances the ability of mutant K-RAS to promote tumorigenesis. Here we show that RASSF1A complexes with and stabilizes the protein DAB2IP. DAB2IP is a tumor suppressor itself and acts, in part, as a negative regulator (GAP) for RAS. Thus, loss of RASSF1A results in the reduced expression of DAB2IP, which promotes the activation of wild type RAS. Therefore, RASSF1A negative cells are likely to show enhanced RAS activity. This may be the first example of a RAS effector being able to back-regulate RAS activity.

Abstract

Lung cancer is the leading cause of cancer-related death worldwide. Lung cancer is commonly driven by mutations in the RAS oncogenes, the most frequently activated oncogene family in human disease. RAS-induced tumorigenesis is inhibited by the tumor suppressor RASSF1A, which induces apoptosis in response to hyperactivation of RAS. RASSF1A expression is suppressed in cancer at high rates, primarily owing to promoter hypermethylation. Recent reports have shown that loss of RASSF1A expression uncouples RAS from apoptotic signaling in vivo, thereby enhancing tumor aggressiveness. Moreover, a concomitant upregulation of RAS mitogenic signaling upon RASSF1A loss has been observed, suggesting RASSF1A may directly regulate RAS activation. Here, we present the first mechanistic evidence for control of RAS activation by RASSF1A. We present a novel interaction between RASSF1A and the Ras GTPase Activating Protein (RasGAP) DAB2IP, an important negative regulator of RAS. Using shRNA-mediated knockdown and stable overexpression approaches, we demonstrate that RASSF1A upregulates DAB2IP protein levels in NSCLC cells. Suppression of RASSF1A and subsequent downregulation of DAB2IP enhances GTP loading onto RAS, thus increasing RAS mitogenic signaling in both mutant- and wildtype-RAS cells. Moreover, co-suppression of RASSF1A and DAB2IP significantly enhances in vitro and in vivo growth of wildtype-RAS cells. Tumors expressing wildtype RAS, therefore, may still suffer from hyperactive RAS signaling when RASSF1A is downregulated. This may render them susceptible to the targeted RAS inhibitors currently in development.

Exploiting codon usage identifies intensity-specific modifiers of Ras/MAPK signaling in vivo

Signal transduction pathways are intricately fine-tuned to accomplish diverse biological processes. An example is the conserved Ras/mitogen-activated-protein-kinase (MAPK) pathway, which exhibits context-dependent signaling output dynamics and regulation. Here, by altering codon usage as a novel platform to control signaling output, we screened the Drosophila genome for modifiers specific to either weak or strong Ras-driven eye phenotypes. Our screen enriched for regions of the genome not previously connected with Ras phenotypic modification. We mapped the underlying gene from one modifier to the ribosomal gene RpS21. In multiple contexts, we show that RpS21 preferentially influences weak Ras/MAPK signaling outputs. These data show that codon usage manipulation can identify new, output-specific signaling regulators, and identify RpS21 as an in vivo Ras/MAPK phenotypic regulator.

Cellular communication is critical in controlling the growth of organs and must be carefully regulated to prevent disease. The Ras signaling pathway is frequently used for cellular communication of tissue growth regulation but can operate at different signaling strengths. Here, we used a novel strategy to identify genes that specifically tune weak or strong Ras signaling states. We find that the gene RpS21 preferentially tunes weak Ras signaling states.

Histone demethylase Jmjd3 modulates osteoblast apoptosis induced by tumor necrosis factor-alpha through directly targeting RASSF5

Purpose: Regulation of gene expression is fine-tuned by a dynamic equilibrium between repressive modifications and transcriptional activation of histone tails. Jumonji domain-containing 3 (Jmjd3), also known as KDM6B, is a specific histone demethylase for trimethylation on histone H3 lysine 27 (H3K27me3) that specifically removes the methylation of H3K27me3 and promotes gene expression. Our previous study showed that Jmjd3 inhibits serum deprivation-induced osteoblast apoptosis. In this study, we clarified the role of Jmjd3 in tumor necrosis factor-alpha (TNF-α)-induced osteoblast apoptosis. Materials and Methods: Jmjd3 activity was inhibited by GSK-J4. Transfection of osteoblastic murine MC3T3-E1 cells with short hairpin RNA (shRNA) was used to establish stable Jmjd3 knockdown cells. Osteoblast apoptosis was detected using Annexin V-APC/PI staining, cysteinyl aspartate specific protease-3 (caspase-3) activity assays, and Western blot. Real-time polymerase chain reaction (PCR) and chromatin immunoprecipitation (ChIP) assays were performed to clarify the mechanism responsible for Jmjd3-regulated osteoblast apoptosis induced by TNF-α. Results: Based on Annexin V-APC/PI staining, caspase-3 activation, and poly ADP-ribose polymerase (PARP) cleavage, pretreatment with GSK-J4 and knockdown of Jmjd3 by shRNA transfection each inhibited osteoblast apoptosis. Furthermore, knockdown of Jmjd3 decreased the expression of Ras association domain family 5 (RASSF5), which is a pro-apoptotic gene of the Ras associated domain family. H3K27me3 levels in the promoter region of RASSF5 were up-regulated in the Jmjd3 knockdown cells. Conclusions: Jmjd3 regulated TNF-α-induced osteoblast apoptosis by targeting RASSF5.

miR-532-3p: a possible altered miRNA in cumulus cells of infertile women with advanced endometriosis

RESEARCH QUESTION

Is the profile of microRNA (miRNA) altered in cumulus cells of infertile women with early (EI/II) and advanced (EIII/IV) endometriosis?

DESIGN

In this prospective case-control study, a miRNA profile including 754 targets was evaluated in samples of cumulus cells from infertile women with endometriosis (5 EI/II, 5 EIII/IV) and infertile controls (5, male and/or tubal factor) undergoing ovarian stimulation for intracytoplasmic sperm injection, using TaqMan® Array Human MicroRNA Cards A and B. The groups were compared with Kruskal-Wallis test, followed by Benjamini-Hochberg correction and Dunn's post hoc test. An in silico enrichment analysis was performed to list the possibly altered pathways in which the altered miRNA target genes are involved.

RESULTS

Only the miRNA miR-532-3p showed significant differences among the analysed groups, being down-regulated in the EIII/IV group compared with the infertile control group, as well as compared with the EI/II group. The enrichment analysis showed that some genes regulated by this miRNA are involved in important pathways for the acquisition of oocyte competence, such as the oxytocin, calcium, Wnt, FoxO, ErbB and Ras signalling pathways, as well as the oocyte meiosis pathway.

CONCLUSION

The present findings bring new perspectives to understanding the follicular microenvironment of infertile women with different stages of endometriosis. It is suggested that the dysregulation of miR-532-3p may be a potential mechanism involved in the aetiopathogenesis of endometriosis-related infertility. Further studies are needed to evaluate these pathways in cumulus cells of infertile women with the disease, as well as their impact on the acquisition of oocyte competence.

Novel tumour suppressor roles for GZMA and RASGRP1 in Theileria annulata-transformed macrophages and human B lymphoma cells

Theileria annulata is a tick-transmitted apicomplexan parasite that infects and transforms bovine leukocytes into disseminating tumours that cause a disease called tropical theileriosis. Using comparative transcriptomics we identified genes transcriptionally perturbed during Theileria-induced leukocyte transformation. Dataset comparisons highlighted a small set of genes associated with Theileria-transformed leukocyte dissemination. The roles of Granzyme A (GZMA) and RAS guanyl-releasing protein 1 (RASGRP1) were verified by CRISPR/Cas9-mediated knockdown. Knocking down expression of GZMA and RASGRP1 in attenuated macrophages led to a regain in their dissemination in Rag2/γC mice confirming their role as dissemination suppressors in vivo. We further evaluated the roles of GZMA and RASGRP1 in human B lymphomas by comparing the transcriptome of 934 human cancer cell lines to that of Theileria-transformed bovine host cells. We confirmed dampened dissemination potential of human B lymphomas that overexpress GZMA and RASGRP1. Our results provide evidence that GZMA and RASGRP1 have a novel tumour suppressor function in both T. annulata-infected bovine host leukocytes and in human B lymphomas.

RAS Function in cancer cells: translating membrane biology and biochemistry into new therapeutics

The three human RAS proteins are mutated and constitutively activated in ∼20% of cancers leading to cell growth and proliferation. For the past three decades, many attempts have been made to inhibit these proteins with little success. Recently; however, multiple methods have emerged to inhibit KRAS, the most prevalently mutated isoform. These methods and the underlying biology will be discussed in this review with a special focus on KRAS-plasma membrane interactions.

The Role of Transcriptional Factor Brachyury on Cell Cycle Regulation in Non-small Cell Lung Cancer

Lung cancer is the leading cause of cancer-related death, and non-small cell lung cancer (NSCLC) accounts for almost 80-85% of all lung cancer cases. The transcriptional factor brachyury has been verified to promote tumor cells migrate, invade, and metastasis in various types of tumors, whereas divergent roles of brachyury on cell proliferation have been reported in several types of tumor cells. In this study, we attempted to explore the effect of brachyury on the cell cycle progression and proliferation capability of NSCLC cells. Firstly, we performed RNA-sequence and ChIP-sequence to explore underlying downstream pathways regulated by brachyury. Cell proliferation and colony formation assays were utilized to detect the effect of brachyury on the proliferation ability of two types of lung NSCLC cells: H460 and Calu-1, which represent different brachyury expression levels. Following cell cycle and cell apoptosis assays were used to investigate the mechanism by which brachyury promotes NSCLC grow and progression. RNA-sequence and ChIP-sequence (ChIP-seq) showed that one of the vital downstream pathways regulated by brachyury involves in cell cycle progression. Through cell proliferation assays and colony formation assays, we found that inhibition of brachyury could decrease the capability of proliferation in H460 cells. We also found that brachyury overexpression could prevent the transition from G0/G1 to S phase in Calu-1 cells, and brachyury knockdown could decrease the transition of G2/M phase in H460 cells. The cell apoptosis assays showed that inhibition of brachyury could promote apoptosis in H460 cells. In this study we demonstrate that brachyury and downstream target genes together involve in tumor cell cycle regulation by inducing accelerated transition through G2/M, promote tumor cell proliferation and inhibit apoptosis in lung NSCLC H460 cells. Targeting brachyury expression could be developed into a promising avenue for the prevention of lung cancer progression.

Peroxiredoxin I deficiency increases keratinocyte apoptosis in a skin tumor model via the ROS-p38 MAPK pathway

Keratinocyte hyperproliferation is an essential link in skin cancer pathogenesis. Peroxiredoxin I (Prx I) is known to regulate cancer cell proliferation, differentiation, and apoptosis, but its role in skin cancer remains unclear. This study aimed to elucidate the role and mechanism of Prx I in skin cancer pathogenesis. Dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) were used to create a skin tumor model of the initiation/promotion stage of cancer. The role of Prx I in H₂O₂-induced keratinocyte apoptosis was also investigated. After DMBA/TPA treatment, Prx I deficiency was significantly associated with less skin tumors, lower Bcl-2 expression, and higher p-p38 and cleaved caspase-3 expressions in Prx I knockout tumors than in wild-type controls. H₂O₂ stimulation caused more cellular apoptosis in Prx I knockdown HaCaT cells than in normal HaCaT cells. The signaling study revealed that Bcl-2, p-p38, and cleaved caspase-3 expressions were consistent with the results in the tumors. In conclusion, the deletion of Prx I triggered the DMBA/TPA-induced skin tumor formation in vivo and in vitro by regulating the reactive oxygen species (ROS)-p38 mitogen-activated protein kinase (MAPK) pathway. These findings provide a theoretical basis for treating skin cancer.

Reduced replication origin licensing selectively kills KRAS-mutant colorectal cancer cells via mitotic catastrophe

To unravel vulnerabilities of KRAS-mutant CRC cells, a shRNA-based screen specifically inhibiting MAPK pathway components and targets was performed in CaCo2 cells harboring conditional oncogenic KRAS^G12V. The custom-designed shRNA library comprised 121 selected genes, which were previously identified to be strongly regulated in response to MEK inhibition. The screen showed that CaCo2 cells expressing KRAS^G12V were sensitive to the suppression of the DNA replication licensing factor minichromosome maintenance complex component 7 (MCM7), whereas KRAS^wt CaCo2 cells were largely resistant to MCM7 suppression. Similar results were obtained in an isogenic DLD-1 cell culture model. Knockdown of MCM7 in a KRAS-mutant background led to replication stress as indicated by increased nuclear RPA focalization. Further investigation showed a significant increase in mitotic cells after simultaneous MCM7 knockdown and KRAS^G12V expression. The increased percentage of mitotic cells coincided with strongly increased DNA damage in mitosis. Taken together, the accumulation of DNA damage in mitotic cells is due to replication stress that remained unresolved, which results in mitotic catastrophe and cell death. In summary, the data show a vulnerability of KRAS-mutant cells towards suppression of MCM7 and suggest that inhibiting DNA replication licensing might be a viable strategy to target KRAS-mutant cancers.

BRAF and KRAS mutations in metastatic colorectal cancer: future perspectives for personalized therapy

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide and 30% of patients with CRC experience metastasis. Patients with metastatic colorectal cancer (mCRC) have a 5-year overall survival rate of <10%. V-raf murine sarcoma viral oncogene homolog B1 (BRAF) and V-Ki-ras2 Kirsten ratsarcoma viral oncogene homolog (KRAS) mutations are mostly studied in mCRC, as clinical trials found that first-line chemotherapy with anti-epidermal growth factor receptor agent confers limited efficacy for mCRC. Treatment decisions for early-stage mCRC do not consider BRAF or KRAS mutations, given the dramatically poor prognosis conferred by these mutations in clinical trials. Thus, it is necessary to identify patients with mCRC harboring BRAF or KRAS mutations to formulate rational therapeutic strategies to improve prognosis and survival. BRAF and KRAS mutations occur in ∼10% and ∼44% of patients with mCRC, respectively. Although the survival rate of patients with mCRC has improved in recent years, the response and prognosis of patients with the aforementioned mutations are still poor. There is a substantial unmet need for prospective personalized therapies for patients with BRAF- or KRAS-mutant mCRC. In this review, we focus on BRAF and KRAS mutations to understand the mechanisms underlying resistance and improving the response rate, outcomes, and prognosis of patients with mCRC bearing these mutations and to discuss prospective personalized therapies for BRAF- and KRAS-mutant mCRC.

Comparison of the transcriptional profile in the decidua of early-onset and late-onset pre-eclampsia

AIM

To compare early-onset pre-eclampsia (EOPE) and late-onset pre-eclampsia (LOPE) and provide insight into the pathophysiology of pre-eclampsia (PE).

METHODS

Our recent work compared the transcriptomics in decidua of EOPE, LOPE and normal pregnancies (NP).

RESULTS

We found there are a significant number of genes uniquely expressed in the decidua of EOPE and LOPE comparing with NP. Moreover, EOPE and LOPE have their distinct profiles. Unique EOPE-associated genes were mainly involved in apoptosis related pathways such as 'apoptosis' and 'Ras signaling pathway'. PIK3CB and BCL-2 are the core regulatory genes in EOPE decidua, their abnormal expression caused decidual abnormal apoptosis which is relevant to the pathogenesis of EOPE. Whereas, LOPE is a more complicated entity which has more special LOPE-associated genes involved in decidua differentiation, especially in 'gap junction pathway', 'vascular smooth muscle contraction' and 'long-term depression'. PIK3CB, FLT1, CBLC and ITGA7 are the core regulatory genes differentially expressed in EOPE decidua comparing with LOPE.

CONCLUSION

In brief, the different decidual transcriptomics of EOPE and LOPE may correlate with their different etiology. These findings highlight the complex pathophysiology of PE and provide potential targets for a new treatment strategy in patients with PE.

Pro-apoptotic and pro-proliferation functions of the JNK pathway of Drosophila: roles in cell competition, tumorigenesis and regeneration

The Jun N-terminal kinase (JNK) is a member of the mitogen-activated protein kinase family. It appears to be conserved in all animal species where it regulates important physiological functions involved in apoptosis, cell migration, cell proliferation and regeneration. In this review, we focus on the functions of JNK in Drosophila imaginal discs, where it has been reported that it can induce both cell death and cell proliferation. We discuss this apparent paradox in the light of recent findings and propose that the pro-apoptotic and the pro-proliferative functions are intrinsic properties of JNK activity. Whether one function or another is predominant depends on the cellular context.

The Function of RAS Mutation in Cancer and Advances in its Drug Research

RAS (H-ras, K-ras, and N-ras), as the second largest mutated gene driver in various human cancers, has long been a vital research target for cancer. Its function is to transform the extracellular environment into a cascade of intracellular signal transduction. RAS mutant protein regulates tumor cell proliferation, apoptosis, metabolism and angiogenesis through downstream MAPK, PI3K and other signaling pathways. In KRAS or other RAS-driven cancers, current treatments include direct inhibitors and upstream/downstream signaling pathway inhibitors. However, the research on these inhibitors has been largely restricted due to their escape inhibition and off-target toxicity. In this paper, we started with the role of normal and mutant RAS genes in cancer, elucidated the relevant RAS regulating pathways, and highlighted the important research advancements in RAS inhibitor research. We concluded that for the crosstalk between RAS pathways, the effect of single regulation may be limited, and the multi-target drug combined compensation mechanism is becoming a research hotspot.

NRAS rs2273267 A>T polymorphism reduces neuroblastoma risk in Chinese children

Neuroblastoma is an extracranial solid tumor that mainly occurs in childhood. Mutations of NRAS gene have been described in several cancers. However, whether NRAS gene polymorphisms can predict the risk of neuroblastoma have not been investigated. We hypothesized that variations of NRAS gene contribute to neuroblastoma predisposition. Therefore, we conducted a multi-center case-control study using 263 cases and 715 controls to examine the association of NRAS gene rs2273267 A>T polymorphism and neuroblastoma risk. We calculated odds ratios (ORs) and corresponding 95% confidence intervals (CIs) to assess the strength of the associations. Relative to those with AA genotype, subjects with AT/TT genotype had reduced neuroblastoma risk (adjusted OR = 0.72, 95% CI = 0.54-0.96, P = 0.024). Stratified analysis revealed that rs2273267 AT/TT carriers were less likely to develop neuroblastoma for patients with tumor originating from the adrenal gland (adjusted OR = 0.67, 95% CI = 0.45-0.99, P = 0.047) and clinical stages III + IV (adjusted OR = 0.57, 95% CI = 0.36-0.90, P = 0.015). Our findings underline the likely importance of NRAS gene rs2273267 A>T in the risk of neuroblastoma. Further independent case-control studies with functional analysis are needed to verify the role of NRAS gene rs2273267 A>T polymorphism in the risk of neuroblastoma.

Pumping the brakes on RAS - negative regulators and death effectors of RAS

Mutations that activate the RAS oncoproteins are common in cancer. However, aberrant upregulation of RAS activity often occurs in the absence of activating mutations in the RAS genes due to defects in RAS regulators. It is now clear that loss of function of Ras GTPase-activating proteins (RasGAPs) is common in tumors, and germline mutations in certain RasGAP genes are responsible for some clinical syndromes. Although regulation of RAS is central to their activity, RasGAPs exhibit great diversity in their binding partners and therefore affect signaling by multiple mechanisms that are independent of RAS. The RASSF family of tumor suppressors are essential to RAS-induced apoptosis and senescence, and constitute a barrier to RAS-mediated transformation. Suppression of RASSF protein expression can also promote the development of excessive RAS signaling by uncoupling RAS from growth inhibitory pathways. Here, we will examine how these effectors of RAS contribute to tumor suppression, through both RAS-dependent and RAS-independent mechanisms.

Role of Human Galectins in Inflammation and Cancers Associated with Endometriosis

Galectins are a family of β-galactoside-binding proteins that contribute to multiple cellular functions, including immune surveillance and apoptosis. Human galectins are also important regulators of inflammation, making them a research target for various inflammatory diseases and tumorigenesis associated with pro-inflammatory conditions. This review focuses on the involvement of human galectins in modulation of inflammation and in the pathophysiology of endometriosis and endometriosis-associated neoplasms. Endometriosis is a chronic inflammatory disease with unknown etiology. Galectins-1, -3 and -9 were found to be overexpressed in ectopic and eutopic endometrium of females with endometriosis compared to those without endometriosis. These findings suggest galectins’ role in the progression on endometriotic lesions and their potential use as diagnostic biomarkers and/or targets for therapeutic approaches. Galectins-1, -3, and -9 have also been implicated in the development of endometriosis-associated neoplasms. Furthermore, galectin-3 has been shown to interact with KRAS protein and contribute to cellular growth, proliferation, inflammation, and the uptake of nutrients in endometriotic lesions and may be involved in the maintenance and propagation of endometriosis. These galectins have been shown to be upregulated in certain forms of cervical, ovarian, endometrial, and colon cancer associated with endometriosis and have become a potential target for anti-cancer therapies.