The functions and regulation of the PTEN tumour suppressor: new modes and prospects

PTEN regulated by gga-miR-20a-5p is involved in chicken macrophages inflammatory response to APEC infection via autophagy

Colibacillosis, a bacterial disease caused by avian pathogenic E. coli (APEC), is a prevalent condition in the poultry industry, resulting in substantial economic losses annually. Previously, we identified PTEN as a crucial candidate gene that may play a significant role in chicken's immune response to APEC infection. Bioinformatics analysis indicated that the PTEN protein was unstable, hydrophilic and nuclear localization, with multiple putative phosphorylation sites and a high degree of similarity to duck and goose PTEN. Moreover, PTEN exhibited high expression levels in various tissues such as the stomach, cecum, small intestine, spleen, thymus, harderian gland, muscle, cerebrum, cerebellum, lung, and liver in comparison to heart tissue. Overexpression of PTEN resulted in a significant promotion of the expression level of pro-apoptosis genes and inflammatory mediators, as well as the production of NO, with or without APEC infection, which led to cellular injury. Furthermore, overexpression of PTEN was found to regulate the expression levels of autophagy related genes, regardless of APEC infection. Additionally, PTEN was a target gene of gga-miR-20a-5p and regulated by gga-miR-20a-5p upon APEC infection. Taken together, these findings establish a foundation for investigating the biological function of chicken PTEN, providing a potential target for future treatments against APEC infection as well as the breeding of genetically resistant poultry.

Suppressive cancer nonstop extension mutations increase C-terminal hydrophobicity and disrupt evolutionarily conserved amino acid patterns

Nonstop extension mutations, a.k.a. stop-lost or stop-loss mutations, convert a stop codon into a sense codon resulting in translation into the 3' untranslated region until the next in-frame stop codon, thereby extending the C-terminus of a protein. In cancer, only nonstop mutations in SMAD4 have been functionally characterized, while the impact of other nonstop mutations remain unknown. Here, we exploit our pan-cancer NonStopDB dataset and test all 2335 C-terminal extensions arising from somatic nonstop mutations in cancer for their impact on protein expression. In a high-throughput screen, 56.1% of the extensions effectively reduce protein abundance. Extensions of multiple tumor suppressor genes like PTEN, APC, B2M, CASP8, CDKN1B and MLH1 are effective and validated for their suppressive impact. Importantly, the effective extensions possess a higher hydrophobicity than the neutral extensions linking C-terminal hydrophobicity with protein destabilization. Analyzing the proteomes of eleven different species reveals conserved patterns of amino acid distribution in the C-terminal regions of all proteins compared to the proteomes like an enrichment of lysine and arginine and a depletion of glycine, leucine, valine and isoleucine across species and kingdoms. These evolutionary selection patterns are disrupted in the cancer-derived effective nonstop extensions.

Targeted Microglial Membrane-Coated MicroRNA Nanosponge Mediates Inhibition of Glioblastoma

Glioblastoma (GBM) is the most prevalent primary brain tumor. Recent research emphasizes the crucial role of microRNAs (miRs) in GBM pathogenesis, and targeting miRs offers an effective approach for precise GBM therapy. However, inhibiting a single miR may not be sufficient due to the compensatory mechanisms of GBM. Herein, we developed a miR-nanosponge capable of specifically capturing multiple miRs involved in tumor growth, migration, invasion, angiogenesis, and the creation of an immunosuppressive microenvironment, thereby offering a comprehensive treatment for GBM. Coated with BV2 cell membrane (BM) for enhanced blood-brain barrier (BBB) crossing and GBM targeting, the BM@miR-nanosponge targets miR-9, miR-21, miR-215, and miR-221, significantly inhibiting GBM progression and modulating the immune system for a thorough GBM eradication. The BM@miR-nanosponge notably extended the median survival time of GBM-bearing mice and outperformed the standard treatment drug temozolomide (TMZ). This study introduces a comprehensive miR-based strategy for GBM treatment and highlights the importance of targeting multiple miRs associated with tumor survival for effective therapy.

Conditional Pten inactivation in pituitary results in sex-specific prolactinoma formation

Pituitary tumors, including prolactinomas, present significant clinical challenges that require a deeper understanding of their molecular roots for improved diagnostics and therapies. Here, we investigate the role of the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K) pathway in pituitary tumorigenesis using a mouse model. Conditional knockout of Pten in all pituitary cell lineages resulted in prolactinoma formation exclusively in female mice, demonstrating the critical role of PTEN in pituitary homeostasis. While Pten inactivation induced Akt activation in all pituitary cells, only prolactin-producing cells exhibited tumorigenic changes, suggesting specific cell-type effects. Histological and molecular analyses of prolactinomas revealed similarities with human pituitary tumors, such as decreased vascularization and cell adhesion proteins and increased accumulation of cell cycle proteins. Notably, prolactinomas displayed diminished levels of phosphorylated extracellular signal-regulated kinase (ERK), implicating downregulation of ERK in tumorigenesis. Finally, we analyzed PTEN/PI3K activation in a collection of human pituitary tumors. Overall, our study delineates the intricate interplay between the PTEN and ERK signaling pathways, providing insights into sex-specific mechanisms of pituitary tumorigenesis and potential therapeutic strategies for prolactinomas.

Targeting mRNA-coding genes in prostate cancer using CRISPR/Cas9 technology with a special focus on androgen receptor signaling

BACKGROUND

Prostate cancer is among prevalent cancers in men. Numerous strategies have been proposed to intervene with the important prostate cancer-related signaling pathways. Among the most promising strategies is CRISPR/Cas9 strategy. This strategy has been used to modify expression of a number of genes in prostate cancer cells.

AIMS

This review summarizes the most recent progresses in the application of CRISPR/Cas9 strategy in modification of prostate cancer-related phenotypes with an especial focus on pathways related to androgen receptor signaling.

CONCLUSION

CRISPR/Cas9 technology has successfully targeted several genes in the prostate cancer cells. Moreover, the efficiency of this technique in reducing tumor burden has been tested in animal models of prostate cancer. Most of targeted genes have been related with the androgen receptor signaling. Targeted modulation of these genes have affected growth of castration-resistant prostate cancer. PI3K/AKT/mTOR signaling and immune response-related genes have been other targets that have been successfully modulated by CRISPR/Cas9 technology in prostate cancer. Based on the rapid translation of this technology into the clinical application, it is anticipated that novel treatments based on this technique change the outcome of this malignancy in future.

HUC-MSC-derived exosomes repaired the damage induced by hydroquinone to 16HBE cells via miR-221/PTEN pathway

Mesenchymal stem cell - originated exosomes (MSC-exo) are promising non-cellular treatment agents for various diseases. The present study aimed to explore whether human umbilical cord MSC - originated exosomes (HUC-MSC-exo) have the function of protecting human cells (16HBE) against the damage caused by HQ and the related mechanism. HUC-MSC-exo was isolated with differential gradient ultracentrifugation method and characterized by using transmission electron microscope (TEM). 16HBE cells were used as the tool cells and co-cultured with HUC-MSC-exo. Confocal laser scanning microscope was employed to confirm the ingestion of HUC-MSC-exo by 16HBE. Cell proliferation, migration, oxidative stress, DNA and chromosome damages of 16HBE were analyzed under HQ stress, and the role of miR-221/PTEN axis was investigated. Our data showed that under HQ stress, different groups of cells exhibited significantly decreased proliferation and migration abilities, and significant oxidative stress, DNA and chromosome damage effects. HUC-MSC-exo could alleviate the cytotoxic, oxidative stress and genotoxic damage effects of HQ on 16HBE cells. Mechanistically, HQ exposure up-regulated the level of miR-221 and down-regulated PTEN, while HUC-MSC-exo could significantly reduce the level of miR-221 and promote PTEN expression, which was involved in alleviating the toxic effects of HQ on 16HBE cells. Our data indicates that HUC-MSC-exo can alleviate the oxidative stress, cytotoxic and genotoxic effects of HQ on 16HBE cells via miR-221/PTEN pathway, and it may be a promising agent for protecting against the toxicity of HQ.

QTL Mapping-Based Identification of Visceral White-Nodules Disease Resistance Genes in Larimichthys polyactis

Disease outbreaks in aquaculture have recently intensified. In particular, visceral white-nodules disease, caused by Pseudomonas plecoglossicida, has severely hindered the small yellow croaker (Larimichthys polyactis) aquaculture industry. However, research on this disease is limited. To address this gap, the present study employed a 100K SNP chip to genotype individuals from an F1 full-sib family, identify single nucleotide polymorphisms (SNPs), and construct a genetic linkage map for this species. A high-density genetic linkage map spanning a total length of 1395.72 cM with an average interval of 0.08 cM distributed across 24 linkage groups was obtained. Employing post-infection survival time as an indicator of disease resistance, 13 disease resistance-related quantitative trait loci (QTLs) were detected, and these regions included 169 genes. Functional enrichment analyses pinpointed 11 candidate disease resistance-related genes. RT-qPCR analysis revealed that the genes of chmp1a and arg1 are significantly differentially expressed in response to P. plecoglossicida infection in spleen and liver tissues, indicating their pivotal functions in disease resistance. In summary, in addition to successfully constructing a high-density genetic linkage map, this study reports the first QTL mapping for visceral white-nodules disease resistance. These results provide insight into the intricate molecular mechanisms underlying disease resistance in the small yellow croaker.

The cellular signaling and regulatory role of protein phosphatase in tumor diagnosis: Upstream miRNAs of PTEN

Protein phosphatases have demonstrated considerable promise in the realm of early tumor diagnosis across various malignancies. These enzymes play a critical role in modulating the PI3K-Akt signaling pathway, which is integral to cellular processes such as proliferation, survival, and migration. When the activity of protein phosphatases becomes abnormal, it can disrupt these essential signaling pathways, potentially leading to the initiation and progression of tumors. Consequently, monitoring for abnormal expression and activity levels of protein phosphatases could serve as a vital biomarker for early cancer detection. By identifying these alterations, clinicians may be better equipped to diagnose tumors at an earlier stage, significantly improving patient outcomes.In summary, our study highlights the multifaceted and significant role of PTEN in various forms of cancer, including esophageal squamous cell carcinoma (ESCA). Further analysis showed that the expression levels of protein phosphatase and PTEN protein were significantly associated with the early diagnosis of tumors, especially in the early stage of tumors, and their detection sensitivity and specificity were high. Therefore, by detecting the expression of protein phosphatase and PTEN protein, the early diagnosis of tumor can be achieved, and the therapeutic effect and prognosis of patients can be improved.

The Role of Non-Coding RNAs in Regulating Cachexia Muscle Atrophy

Cachexia is a late consequence of various diseases that is characterized by systemic muscle loss, with or without fat loss, leading to significant mortality. Multiple signaling pathways and molecules that increase catabolism, decrease anabolism, and interfere with muscle regeneration are activated. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play vital roles in cachexia muscle atrophy. This review mainly provides the mechanisms of specific ncRNAs to regulate muscle loss during cachexia and discusses the role of ncRNAs in cachectic biomarkers and novel therapeutic strategies that could offer new insights for clinical practice.

PTEN Deficiency Induced by Extracellular Vesicle miRNAs from Clonorchis sinensis Potentiates Cholangiocarcinoma Development by Inhibiting Ferroptosis

The human phosphatase and tensin homolog (PTEN) is a tumor suppressor. A slight deficiency in PTEN might cause cancer susceptibility and progression. Infection by the liver fluke Clonorchis sinensis could lead to persistent loss of PTEN in cholangiocarcinoma. However, the mechanism of PTEN loss and its malignant effect on cholangiocarcinoma have not yet been elucidated. Extracellular vesicles secreted by Clonorchis sinensis (CS-EVs) are rich in microRNAs (miRNAs) and can mediate communication between hosts and parasites. Herein, we delved into the miRNAs present in CS-EVs, specifically those that potentially target PTEN and modulate the progression of cholangiocarcinoma via ferroptosis mechanisms. CS-EVs were extracted by differential ultra-centrifugation for high-throughput sequencing of miRNA. Lentiviral vectors were used to construct stably transfected cell lines. Erastin was used to construct ferroptosis induction models. Finally, 36 miRNAs were identified from CS-EVs. Among them, csi-miR-96-5p inhibited PTEN expression according to the predictions and dual luciferase assay. The CCK-8 assay, xenograft tumor assays and transwell assay showed that csi-miR-96-5p overexpression and PTEN knockout significantly increased the proliferation and migration of cholangiocarcinoma cells and co-transfection of PTEN significantly reversed the effect. In the presence of erastin, the cell proliferation and migration ability of the negative transfection control group were significantly impaired, although they did not significantly change with transfection of csi-miR-96-5p and PTEN knockout, indicating that they obtained ferroptosis resistance. Mechanistically, csi-miR-96-5p and PTEN knockout significantly inhibited ferroptosis through a decrease in ferrous ion (Fe2+) and malondialdehyde (MDA), and an increase in glutathione reductase (GSH), Solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). In conclusion, loss of PTEN promoted the progression of cholangiocarcinoma via the ferroptosis pathway and csi-miR-96-5p delivered by CS-EVs may mediate this process.

Redox remodeling of central metabolism as a driving force for cellular protection, proliferation, differentiation, and dysfunction

The production of reactive oxygen species (ROS) is elevated via metabolic hyperactivation in response to a variety of stimuli such as growth factors and inflammation. Tolerable amounts of ROS moderately inactivate enzymes via oxidative modification, which can be reversed back to the native form in a redox-dependent manner. The excessive production of ROS, however, causes cell dysfunction and death. Redox-reactive enzymes are present in primary metabolic pathways such as glycolysis and the tricarboxylic acid cycle, and these act as floodgates for carbon flux. Oxidation of a specific form of cysteine inhibits glyceraldehyde-3-phosphate dehydrogenase, which is reversible, and causes an accumulation of upstream intermediary compounds that increases the flux of glucose-6-phosphate to the pentose phosphate pathway. These reactions increase the NADPH and ribose-5-phosphate that are available for reductive reactions and nucleotide synthesis, respectively. On the other hand, oxidative inactivation of mitochondrial aconitase increases citrate, which is then recruited to synthesize fatty acids in the cytoplasm. Decreases in the use of carbohydrate for ATP production can be compensated via amino acid catabolism, and this metabolic change makes nitrogen available for nucleic acid synthesis. Coupling of the urea cycle also converts nitrogen to urea and polyamine, the latter of which supports cell growth. This metabolic remodeling stimulates the proliferation of tumor cells and fibrosis in oxidatively damaged tissues. Oxidative modification of these enzymes is generally reversible in the early stages of oxidizing reactions, which suggests that early treatment with appropriate antioxidants promotes the maintenance of natural metabolism.

The humoral immune response of the lepidopteran model insect, silkworm Bombyx mori L., to microbial pathogens

Insects are valuable models for studying innate immunity and its role in combating infections. The silkworm Bombyx mori L., a well-studied insect model, is susceptible to a range of pathogens, including bacteria, fungi, viruses, and microsporidia. Their susceptibility makes it a suitable model for investigating host-pathogen interactions and immune responses against infections and diseases. This review focuses on the humoral immune response and the production of antimicrobial peptides (AMPs), the phenoloxidase (PO) system, and other soluble factors that constitute the primary defense of silkworms against microbial pathogens. The innate immune system of silkworms relies on pattern recognition receptors (PRRs) to recognize pathogen-associated molecular patterns (PAMPs), which then activate various immune pathways including Imd, Toll, JAK/STAT, and RNA interference (RNAi). Their activation triggers the secretion of AMPs, enzymatic defenses (lysozyme and PO), and the generation of reactive oxygen species (ROS). Collectively, these pathways work together to neutralize and eliminate pathogens, thereby contributing to the defense mechanism of silkworms. Understanding the innate immunity of silkworms can uncover conserved molecular pathways and key immune components shared between insects and vertebrates. Additionally, it can provide valuable insights for improving sericulture practices, developing strategies to control diseases affecting silk production, and providing a theoretical foundation for developing pest control measures.

Overcoming Osimertinib Resistance with AKT Inhibition in EGFRm-Driven Non-Small Cell Lung Cancer with PIK3CA/PTEN Alterations

PURPOSE

Osimertinib is an EGFR tyrosine kinase inhibitor indicated for the treatment of EGFR-mutated (EGFRm)-driven lung adenocarcinomas. Osimertinib significantly improves progression-free survival in first-line-treated patients with EGFRm advanced non-small cell lung cancer (NSCLC). Despite the durable disease control, the majority of patients receiving osimertinib eventually develop disease progression.

EXPERIMENTAL DESIGN

ctDNA profiling analysis of on-progression plasma samples from patients treated with osimertinib in both first- (phase III, FLAURA trial) and second-line trials (phase III, AURA3 trial) revealed a high prevalence of PIK3CA/AKT/PTEN alterations. In vitro and in vivo evidence using CRISPR-engineered NSCLC cell lines and patient-derived xenograft (PDX) models supports a functional role for PIK3CA and PTEN mutations in the development of osimertinib resistance.

RESULTS

These alterations are functionally relevant as EGFRm NSCLC cells with engineered PIK3CA/AKT/PTEN alterations develop resistance to osimertinib and can be resensitized by treatment with the combination of osimertinib and the AKT inhibitor capivasertib. Moreover, xenograft and PDX in vivo models with PIK3CA/AKT/PTEN alterations display limited sensitivity to osimertinib relative to models without alterations, and in these double-mutant models, capivasertib and osimertinib combination elicits an improved antitumor effect versus osimertinib alone.

CONCLUSIONS

Together, this approach offers a potential treatment strategy for patients with EGFRm-driven NSCLC who have a suboptimal response or develop resistance to osimertinib through PIK3CA/AKT/PTEN alterations. See related commentary by Vokes et al., p. 3968.

Expression profile of microRNAs in bovine lymphocytes infected with Theileria annulata and treated with buparvaquone

Several miRNA-based studies on Theileria-transformed bovine cells have been conducted; however, the mechanism by which transformed cells exhibit uncontrolled proliferation is not yet fully understood. Therefore, it is necessary to screen more microRNAs that may play a role in the transformation process of host cells infected with Theileria annulata to better understand the transformation mechanisms of Theileria-infected cells. RNA sequencing was used to analyze miRNAs expression in the host bovine lymphocytes infected with T. annulata at different time points after buparvaquone (BW720) treatment and DMSO treatment (control groups). Differential miRNAs related to cell proliferation and apoptosis were identified through comparison with gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and a regulatory network of miRNA-mRNA was constructed. In total, 272 differentially expressed miRNAs were found at 36, 60 and 72 h. The miRNAs change of bta-miR-2285t, novel-miR-622, bta-miR-2478, and novel-miR-584 were significant. Analysis of 27 of these co-differential expressed miRNAs revealed that 15 miRNAs were down-regulated and 12 miRNAs were up-regulated. A further analysis of the changes in the expression of each of these 27 miRNAs in the three datasets suggested that bta-miR-2285t, bta-miR-345-5p, bta-miR-34a, bta-miR-150, and the novel-miR-1372 had significantly changed. Predicted target genes for these 27 miRNAs were analyzed by KEGG and the results demonstrated that EZR, RASSF, SOCS1 were mainly enriched in the signaling pathway microRNAs in cancer. MAPKAPK2, RELB, FLT3LG, and GADD45B were mainly enriched in the MAPK signaling pathway, and some genes were enriched in Axon guidance. This study has provided valuable information to further the understanding of the regulatory function of miRNAs in the host microenvironment and host-parasite interaction mechanisms.

Tudor-SN exacerbates pathological vascular remodeling by promoting the polyubiquitination of PTEN via NEDD4-1

BACKGROUND

Dysregulation of vascular homeostasis can induce cardiovascular diseases and increase global mortality rates. Although lineage tracing studies have confirmed the pivotal role of modulated vascular smooth muscle cells (VSMCs) in the progression of pathological vascular remodeling, the underlying mechanisms are still unclear.

METHODS

The expression of Tudor-SN was determined in VSMCs of artery stenosis, PDGF-BB-treated VSMCs and atherosclerotic plaque. Loss- and gain-of-function approaches were used to explore the role of Tudor-SN in the modulation of VSMCs phenotype both in vivo and in vitro.

RESULTS

In this study, we demonstrate that Tudor-SN expression is significantly elevated in injury-induced arteries, atherosclerotic plaques, and PDGF-BB-stimulated VSMCs. Tudor-SN deficiency attenuates, but overexpression aggravates the synthetic phenotypic switching of VSMCs and pathological vascular remodeling. Loss of Tudor-SN also reduces atherosclerotic plaque formation and increases plaque stability. Mechanistically, PTEN, the major regulator of the MAPK and PI3K-AKT signaling pathways, plays a vital role in Tudor-SN-mediated regulation on proliferation and migration of VSMCs. Tudor-SN facilitates the polyubiquitination and degradation of PTEN via NEDD4-1, thus exacerbating vascular remodeling under pathological conditions. BpV (HOpic), a specific inhibitor of PTEN, not only counteracts the protective effect of Tudor-SN deficiency on proliferation and migration of VSMCs, but also abrogates the negative effect of carotid artery injury-induced vascular remodeling in mice.

CONCLUSIONS

Our findings reveal that Tudor-SN deficiency significantly ameliorated pathological vascular remodeling by reducing NEDD4-1-dependent PTEN polyubiquitination, suggesting that Tudor-SN may be a novel target for preventing vascular diseases.

CRISPR-based dissection of miRNA binding sites using isogenic cell lines is hampered by pervasive noise

Non-coding regulatory sequences play essential roles in adjusting gene output to cellular needs and are thus critical to animal development and health. Numerous such sequences have been identified in mammalian genomes ranging from transcription factors binding motifs to recognition sites for RNA-binding proteins and non-coding RNAs. The advent of CRISPR has raised the possibility of assigning functionality to individual endogenous regulatory sites by facilitating the generation of isogenic cell lines that differ by a defined set of genetic modifications. Here we investigate the usefulness of this approach to assign function to individual miRNA binding sites. We find that the process of generating isogenic pairs of mammalian cell lines with CRISPR-mediated mutations introduces extensive molecular and phenotypic variability between biological replicates making any attempt of assigning function to the binding site essentially impossible. Our work highlights an important consideration when employing CRISPR editing to characterize non-coding regulatory sequences in cell lines and calls for the development and adoption of alternative strategies to address this question in the future.

Effect of calcium concentration on metastasis of hepatocellular carcinoma cells cultured in alginate gel beads

Changes in sodium alginate and calcium ion concentrations have a considerable impact on the structural properties of calcium alginate gel (ALG) beads, consequently influencing the biological characteristics of the cells encapsulated within them. This study aimed to examine the effects of calcium on the metastatic potential of hepatocellular carcinoma (HCC) cells encapsulated in ALG beads. The results showed that the invasion ability of HCC cells significantly increased when they were encapsulated in beads prepared with a calcium concentration of 200 mM compared to those prepared with a calcium concentration of 50 mM. Furthermore, the expression levels of genes related to metastasis were significantly elevated in ALG beads prepared with a calcium concentration of 200 mM. Specifically, the expression of activated matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), and urokinase-type plasminogen activator system proteins was found to be high. Conversely, the expression of phosphatase and tensin homolog deleted on chromosome 10 was observed to be significantly reduced. These findings indicate that manipulating the calcium ion concentration during the fabrication of ALG beads enables the generation of three-dimensional HCC cells with varying metastatic capacities. This model offers a valuable tool for investigating the mechanisms underlying liver cancer metastasis and screening potential therapeutic drugs.

The Eyes Absent family: At the intersection of DNA repair, mitosis, and replication

The Eyes Absent family (EYA1-4) are a group of dual function proteins that act as both tyrosine phosphatases and transcriptional co-activators. EYA proteins play a vital role in development, but are also aberrantly overexpressed in cancers, where they often confer an oncogenic effect. Precisely how the EYAs impact cell biology is of growing interest, fuelled by the therapeutic potential of an expanding repertoire of EYA inhibitors. Recent functional studies suggest that the EYAs are important players in the regulation of genome maintenance pathways including DNA repair, mitosis, and DNA replication. While the characterized molecular mechanisms have predominantly been ascribed to EYA phosphatase activities, EYA co-transcriptional activity has also been found to impact the expression of genes that support these pathways. This indicates functional convergence of EYA phosphatase and co-transcriptional activities, highlighting the emerging importance of the EYA protein family at the intersection of genome maintenance mechanisms. In this review, we discuss recent progress in defining EYA protein substrates and transcriptional effects, specifically in the context of genome maintenance. We then outline future directions relevant to the field and discuss the clinical utility of EYA inhibitors.

Coding, or non-coding, that is the question

The advent of high-throughput sequencing uncovered that our genome is pervasively transcribed into RNAs that are seemingly not translated into proteins. It was also found that non-coding RNA transcripts outnumber canonical protein-coding genes. This mindboggling discovery prompted a surge in non-coding RNA research that started unraveling the functional relevance of these new genetic units, shaking the classic definition of "gene". While the non-coding RNA revolution was still taking place, polysome/ribosome profiling and mass spectrometry analyses revealed that peptides can be translated from non-canonical open reading frames. Therefore, it is becoming evident that the coding vs non-coding dichotomy is way blurrier than anticipated. In this review, we focus on several examples in which the binary classification of coding vs non-coding genes is outdated, since the same bifunctional gene expresses both coding and non-coding products. We discuss the implications of this intricate usage of transcripts in terms of molecular mechanisms of gene expression and biological outputs, which are often concordant, but can also surprisingly be discordant. Finally, we discuss the methodological caveats that are associated with the study of bifunctional genes, and we highlight the opportunities and challenges of therapeutic exploitation of this intricacy towards the development of anticancer therapies.

Comparison among different preclinical models derived from the same patient with a non-functional pancreatic neuroendocrine tumor

Pancreatic neuroendocrine tumors are the second most common tumors of the pancreas, and approximately half of patients are diagnosed with liver metastases. Currently, the improvement in the efficacy of relevant treatment methods is still limited. Therefore, there is an urgent need for in-depth research on the molecular biological mechanism of pancreatic neuroendocrine tumors. However, due to their relatively inert biology, preclinical models are extremely scarce. Here, the patient-derived organoid, and patient-derived xenograft were successfully constructed. These two models and the previously constructed cell line named SPNE1 all derived from the same patient with a grade 3 non-functional pancreatic neuroendocrine tumor, providing new tumor modeling platforms, and characterized using immunohistochemistry, whole-exome sequencing, and single-cell transcriptome sequencing. Combined with a tumor formation experiment in immunodeficient mice, we selected the model that most closely recapitulated the parental tumor. Overall, the patient-derived xenograft model most closely resembled human tumor tissue.

Reversible control of kinase signaling through chemical-induced dephosphorylation

The coordination between kinases and phosphatases is crucial for regulating the phosphorylation levels of essential signaling molecules. Methods enabling precise control of kinase activities are valuable for understanding the kinase functions and for developing targeted therapies. Here, we use the abscisic acid (ABA)-induced proximity system to reversibly control kinase signaling by recruiting phosphatases. Using this method, we found that the oncogenic tyrosine kinase BCR::ABL1 can be inhibited by recruiting various cytoplasmic phosphatases. We also discovered that the oncogenic serine/threonine kinase BRAF(V600E), which has been reported to bypass phosphorylation regulation, can be positively regulated by protein phosphatase 1 (PP1) and negatively regulated by PP5. Additionally, we observed that the dual-specificity kinase MEK1 can be inhibited by recruiting PP5. This suggests that bifunctional molecules capable of recruiting PP5 to MEK or RAF kinases could be promising anticancer drug candidates. Thus, the ABA-induced dephosphorylation method enables rapid screening of phosphatases to precisely control kinase signaling.

Secreted PTEN binds PLXDC2 on macrophages to drive antitumor immunity and tumor suppression

Loss of phosphatase and tensin homolog (PTEN) has been linked to an immunosuppressive tumor microenvironment, but its underlying mechanisms remain largely enigmatic. Here, we report that PTEN can be secreted by the transmembrane emp24 domain-containing protein 10 (TMED10)-channeled protein secretion pathway. Inhibiting PTEN secretion from tumor cells contributes to immunosuppression and impairs the tumor-suppressive role of PTEN, while intratumoral injection of PTEN protein promotes antitumor immunity and suppresses tumor growth in mice. Mechanistically, extracellular PTEN binds to the plexin domain-containing protein 2 (PLXDC2) on macrophages, triggering subsequent activation of JAK2-STAT1 signaling, which switches tumor-associated macrophages (TAMs) from the immunosuppressive to inflammatory phenotype, leading to enhanced activation of CD8+ T and natural killer cells. Importantly, PTEN treatment also enhances the therapeutic efficacy of anti-PD-1 treatment in mice and reverses the immune-suppressive phenotype of patient-derived primary TAMs. These data identify a cytokine-like role of PTEN in immune activation and tumor suppression and demonstrate the therapeutic potential for extracellular administration of PTEN in cancer immunotherapy.

Signaling pathways activated and regulated by stem cell-derived exosome therapy

Stem cell-derived exosomes exert comparable therapeutic effects to those of their parental stem cells without causing immunogenic, tumorigenic, and ethical disadvantages. Their therapeutic advantages are manifested in the management of a broad spectrum of diseases, and their dosing versatility are exemplified by systemic administration and local delivery. Furthermore, the activation and regulation of various signaling cascades have provided foundation for the claimed curative effects of exosomal therapy. Unlike other relevant reviews focusing on the upstream aspects (e.g., yield, isolation, modification), and downstream aspects (e.g. phenotypic changes, tissue response, cellular behavior) of stem cell-derived exosome therapy, this unique review endeavors to focus on various affected signaling pathways. After meticulous dissection of relevant literature from the past five years, we present this comprehensive, up-to-date, disease-specific, and pathway-oriented review. Exosomes sourced from various types of stem cells can regulate major signaling pathways (e.g., the PTEN/PI3K/Akt/mTOR, NF-κB, TGF-β, HIF-1α, Wnt, MAPK, JAK-STAT, Hippo, and Notch signaling cascades) and minor pathways during the treatment of numerous diseases encountered in orthopedic surgery, neurosurgery, cardiothoracic surgery, plastic surgery, general surgery, and other specialties. We provide a novel perspective in future exosome research through bridging the gap between signaling pathways and surgical indications when designing further preclinical studies and clinical trials.

Therapeutic advances of targeting receptor tyrosine kinases in cancer

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

Potentiation by Protein Synthesis Inducers of Translational Readthrough of Pathogenic Premature Termination Codons in PTEN Isoforms

The PTEN tumor suppressor is frequently targeted in tumors and patients with PTEN hamartoma tumor syndrome (PHTS) through nonsense mutations generating premature termination codons (PTC) that may cause the translation of truncated non-functional PTEN proteins. We have previously described a global analysis of the readthrough reconstitution of the protein translation and function of the human canonical PTEN isoform by aminoglycosides. Here, we report the efficient functional readthrough reconstitution of the PTEN translational isoform PTEN-L, which displays a minimal number of PTC in its specific N-terminal extension in association with disease. We illustrate the importance of the specific PTC and its nucleotide proximal sequence for optimal readthrough and show that the more frequent human PTEN PTC variants and their mouse PTEN PTC equivalents display similar patterns of readthrough efficiency. The heterogeneous readthrough response of the different PTEN PTC variants was independent of the length of the PTEN protein being reconstituted, and we found a correlation between the amount of PTEN protein being synthesized and the PTEN readthrough efficiency. Furthermore, combination of aminoglycosides and protein synthesis inducers increased the readthrough response of specific PTEN PTC. Our results provide insights with which to improve the functional reconstitution of human-disease-related PTC pathogenic variants from PTEN isoforms by increasing protein synthesis coupled to translational readthrough.

Gallium complex K6 inhibits colorectal cancer by increasing ROS levels to induce DNA damage and enhance phosphatase and tensin homolog activity

Colorectal cancer (CRC) is one of the most common malignancies worldwide. In the clinical realm, platinum-based drugs hold an important role in the chemotherapy of CRC. Nonetheless, a multitude of patients, due to tumor protein 53 (TP53) gene mutations, experience the emergence of drug resistance. This phenomenon gravely impairs the effectiveness of therapy and long-term prognosis. Gallium, a metallic element akin to iron, has been reported that has the potential to be used to develop new metal anticancer drugs. In this study, we screened and established the gallium complex K6 as a potent antitumor agent in both in vitro and in vivo. K6 exhibited superior efficacy in impeding the growth, proliferation, and viability of CRC cells carrying TP53 mutations compared to oxaliplatin. Mechanistically, K6 escalated reactive oxygen species levels and led deoxyribonucleic acid (DNA) damage. Furthermore, K6 effectively suppressed the phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB)/glycogen synthase kinase 3 beta (GSK3β) pathway, leading to the degradation of its downstream effectors myelocytomatosis (c-Myc) and Krueppel-like factor 5 (KLF5). Conversely, K6 diminished the protein expression of WW domain-containing protein 1 (WWP1) while activating phosphatase and tensin homolog (PTEN) through c-Myc degradation. This dual action further demonstrated the potential of K6 as a promising therapeutic compound for TP53-mutated CRC.

PTEN inhibition enhances sensitivity of ovarian cancer cells to the poly (ADP-ribose) polymerase inhibitor by suppressing the MRE11-RAD50-NBN complex

BACKGROUND

Poly (ADP-ribose) polymerase inhibitors (PARPis) can effectively treat ovarian cancer patients with defective homologous recombination (HR). Loss or dysfunction of PTEN, a typical tumour suppressor, impairs double-strand break (DSB) repair. Hence, we explored the possibility of inhibiting PTEN to induce HR deficiency (HRD) for PARPi application.

METHODS

Functional studies using PTEN inhibitor VO-OHpic and PARPi olaparib were performed to explore the molecular mechanisms in vitro and in vivo.

RESULTS

In this study, the combination of VO-OHpic with olaparib exhibited synergistic inhibitory effects on ovarian cancer cells was demonstrated. Furthermore, VO-OHpic was shown to enhance DSBs by reducing nuclear expression of PTEN and inhibiting HR repair through the modulation of MRE11-RAD50-NBN (MRN) complex, critical for DSB repair. TCGA and GTEx analysis revealed a strong correlation between PTEN and MRN in ovarian cancer. Mechanistic studies indicated that VO-OHpic reduced expression of MRN, likely by decreasing PTEN/E2F1-mediated transcription. Moreover, PTEN-knockdown inhibited expression of MRN, increased sensitivities to olaparib, and induced DSBs. In vivo experiments showed that the combination of VO-OHpic with olaparib exhibited enhanced inhibitory effects on tumour growth.

CONCLUSIONS

Collectively, this study highlights the potential of PTEN inhibitors in combination therapy with PARPis to create HRD for HRD-negative ovarian cancers.

IRTKS promotes osteogenic differentiation by inhibiting PTEN phosphorylation

Insulin stimulates osteoblast proliferation and differentiation as an anabolic agent in bone. Insulin Receptor Tyrosine Kinase Substrate (IRTKS) is involved in insulin signaling as an adapter for insulin receptors (IR). Here, we showed that IRTKS levels were significantly decreased in bone marrow mesenchymal stem cells (BMSCs) derived from the bone marrow of patients with osteoporosis. Based on relevant experiments, we observed that IRTKS promoted the proliferation, migration, and osteoblast differentiation of BMSCs and MC3T3-E1 cells. In addition, we identified a Phosphatase and Tensin homolog deleted on chromosome 10 (PTEN) as a potential active substrate of IRTKS. We demonstrated a direct interaction between IRTKS and PTEN using co-immunoprecipitation. Subsequently, we confirmed that the SH3 domain of IRTKS directly binds to the C-terminal tail of PTEN. Further experimental results demonstrated that PTEN attenuated the promoting effects of IRTKS on the proliferation, migration, and osteoblast differentiation of BMSCs and MC3T3-E1 cells. In conclusion, this study suggests that IRTKS contributes to osteogenic differentiation by inhibiting PTEN phosphorylation and provides a potential therapeutic target for osteoporosis patients.

Ubiquitination and deubiquitination in cancer: from mechanisms to novel therapeutic approaches

Ubiquitination, a pivotal posttranslational modification of proteins, plays a fundamental role in regulating protein stability. The dysregulation of ubiquitinating and deubiquitinating enzymes is a common feature in various cancers, underscoring the imperative to investigate ubiquitin ligases and deubiquitinases (DUBs) for insights into oncogenic processes and the development of therapeutic interventions. In this review, we discuss the contributions of the ubiquitin-proteasome system (UPS) in all hallmarks of cancer and progress in drug discovery. We delve into the multiple functions of the UPS in oncology, including its regulation of multiple cancer-associated pathways, its role in metabolic reprogramming, its engagement with tumor immune responses, its function in phenotypic plasticity and polymorphic microbiomes, and other essential cellular functions. Furthermore, we provide a comprehensive overview of novel anticancer strategies that leverage the UPS, including the development and application of proteolysis targeting chimeras (PROTACs) and molecular glues.

WTAP/IGF2BP3 mediated m6A modification of the EGR1/PTEN axis regulates the malignant phenotypes of endometrial cancer stem cells

Endometrial cancer (EC) stem cells (ECSCs) are pivotal in the oncogenesis, metastasis, immune escape, chemoresistance, and recurrence of EC. However, the specific mechanism of stem cell maintenance in EC cells (ECCs) has not been clarified. We found that WTAP and m6A levels decreased in both EC and ECSCs, and that knocking down WTAP promoted ECCs and ECSCs properties, including proliferation, invasion, migration, cisplatin resistance, and self-renewal. The downregulation of WTAP leads to a decrease in the m6A modification of EGR1 mRNA, and it is difficult for IGF2BP3, as an m6A reader, to recognize and bind to EGR1 mRNA that has lost m6A modification, resulting in a decrease in the stability of EGR1 mRNA. A decrease in the EGR1 level led to a decrease of in the expression tumor suppressor gene PTEN, resulting in deregulation and loss of cellular homeostasis and thereby fostering EC stem cell traits. Notably, the enforced overexpression of WTAP, EGR1, and PTEN inhibited the oncogenic effects of ECCs and ECSCs in vivo, and the combined overexpression of WTAP + EGR1 and EGR1 + PTEN further diminished the tumorigenic potential of these cells. Our findings revealed that the WTAP/EGR1/PTEN pathway is important regulator of EC stem cell maintenance, chemotherapeutic resistance, and tumorigenesis, suggesting a novel and promising therapeutic avenue for treating EC.

Circular RNAs: Epigenetic regulators of PTEN expression and function in cancer

Epigenetic regulation of gene expression, without altering the DNA sequence, is involved in many normal cellular growth and division events, as well as diseases such as cancer. Epigenetics is no longer limited to DNA methylation, and histone modification, but regulatory non-coding RNAs (ncRNAs) also play an important role in epigenetics. Circular RNAs (circRNAs), single-stranded RNAs without 3' and 5' ends, have recently emerged as a class of ncRNAs that regulate gene expression. CircRNAs regulate phosphatase and tensin homolog (PTEN) expression at various levels of transcription, post-transcription, translation, and post-translation under their own regulation. Given the importance of PTEN as a tumor suppressor in cancer that inhibits one of the most important cancer pathways PI3K/AKT involved in tumor cell proliferation and survival, significant studies have been conducted on the regulatory role of circRNAs in relation to PTEN. These studies will be reviewed in this paper to better understand the function of this protein in cancer and explore new therapeutic approaches.

Strategy of combining CDK4/6 inhibitors with other therapies and mechanisms of resistance

Cell cycle-dependent protein kinase 4/6 (CDK4/6) is a crucial kinase that regulates the cell cycle, essential for cell division and proliferation. Hence, combining CDK4/6 inhibitors with other anti-tumor drugs is a pivotal clinical strategy. This strategy can efficiently inhibit the growth and division of tumor cells, reduce the side effects, and improve the quality of life of patients by reducing the dosage of combined anticancer drugs. Furthermore, the combination therapy strategy of CDK4/6 inhibitors could ameliorate the drug resistance of combined drugs and overcome the CDK4/6 resistance caused by CDK4/6 inhibitors. Various tumor treatment strategies combined with CDK4/6 inhibitors have entered the clinical trial stage, demonstrating their substantial clinical potential. This study reviews the research progress of CDK4/6 inhibitors from 2018 to 2022, the related resistance mechanism of CDK4/6 inhibitors, and the strategy of combination medication.

A black phosphorus nanosheet-based RNA delivery system for prostate cancer therapy by increasing the expression level of tumor suppressor gene PTEN via CeRNA mechanism

BACKGROUND

Prostate cancer (PCa) has a high incidence in men worldwide, and almost all PCa patients progress to the androgen-independent stage which lacks effective treatment measures. PTENP1, a long non-coding RNA, has been shown to suppress tumor growth through the rescuing of PTEN expression via a competitive endogenous RNA (ceRNA) mechanism. However, PTENP1 was limited to be applied in the treatment of PCa for the reason of rapid enzymatic degradation, poor intracellular uptake, and excessively long base sequence to be synthesized. Considering the unique advantages of artificial nanomaterials in drug loading and transport, black phosphorus (BP) nanosheet was employed as a gene-drug carrier in this study.

RESULTS

The sequence of PTENP1 was adopted as a template which was randomly divided into four segments with a length of about 1000 nucleotide bases to synthesize four different RNA fragments as gene drugs, and loaded onto polyethyleneimine (PEI)-modified BP nanosheets to construct BP-PEI@RNA delivery platforms. The RNAs could be effectively delivered into PC3 cells by BP-PEI nanosheets and elevating PTEN expression by competitive binding microRNAs (miRNAs) which target PTEN mRNA, ultimately exerting anti-tumor effects.

CONCLUSIONS

Therefore, this study demonstrated that BP-PEI@RNAs is a promising gene therapeutic platform for PCa treatment.

PTEN deficiency induces an extrahepatic cholangitis-cholangiocarcinoma continuum via aurora kinase A in mice

BACKGROUND & AIMS

The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aimed to evaluate the role of PTEN in the pathogenesis of eCCA and identify novel therapeutic targets for this disease.

METHODS

The Pten gene was genetically deleted using the Cre-loxp system in biliary epithelial cells. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry, reverse-transcription PCR, cell culture, and RNA sequencing. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. We also tested the effectiveness of an Aurka inhibitor.

RESULTS

We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as 1 month after birth. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated disease progression, potentially by downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expression of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression.

CONCLUSIONS

Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum that was dependent on Aurka. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA.

IMPACT AND IMPLICATIONS

The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition, cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted disease progression. This model will be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Carbon Nanotube-Mediated Delivery of PTEN Variants: In Vitro Antitumor Activity in Breast Cancer Cells

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a crucial tumor suppressor protein with frequent mutations and alterations. Although protein therapeutics are already integral to numerous medical fields, their potential remains nascent. This study aimed to investigate the impact of stable, unphosphorylated recombinant human full-length PTEN and its truncated variants, regarding their tumor suppression activity with multiwalled-carbon nanotubes (MW-CNTs) as vehicles for their delivery in breast cancer cells (T-47D, ZR-75-1, and MCF-7). The cloning, overexpression, and purification of PTEN variants were achieved from E. coli, followed by successful binding to CNTs. Cell incubation with protein-functionalized CNTs revealed that the full-length PTEN-CNTs significantly inhibited cancer cell growth and stimulated apoptosis in ZR-75-1 and MCF-7 cells, while truncated PTEN fragments on CNTs had a lesser effect. The N-terminal fragment, despite possessing the active site, did not have the same effect as the full length PTEN, emphasizing the necessity of interaction with the C2 domain in the C-terminal tail. Our findings highlight the efficacy of full-length PTEN in inhibiting cancer growth and inducing apoptosis through the alteration of the expression levels of key apoptotic markers. In addition, the utilization of carbon nanotubes as a potent PTEN protein delivery system provides valuable insights for future applications in in vivo models and clinical studies.

Surface-Enhanced Raman Spectroscopy-Based Detection of EMT-Related Targets in Endometrial Cancer: Potential for Diagnosis and Prognostic Prediction

Epithelial-mesenchymal transformation (EMT) is one of the important mechanisms of malignancy in endometrial cancer, and detection of EMT targets is a key challenge to explore the mechanism of endometrial carcinoma (EC) malignancy and discover novel therapeutic targets. This study attempts to use surface-enhanced Raman spectroscopy (SERS), a highly sensitive, ultrafast, and highly specific analytical technology, to rapidly detect microRNA-200a-3p and ZEB1 in endometrial cancer cell lines. The silver nanoparticles were decorated with iodine and calcium ions, can capture the SERS fingerprints of microRNA-200a-3p and ZEB1 protein, and effectively avoid the interference of impurity signals. At the same time, the method has high sensitivity for the detection of the above EMT targets, and the lowest detection limits for microRNA-200a-3p and ZEB1 are 4.5 pmol/mL and 10 ng/mL, respectively. At the lowest detection concentration, the method still has high stability. In addition, principal component analysis can not only identify microRNA-200a-3p and ZEB1 protein from a variety of EMT-associated microRNA and proteins but also identify them in the total RNA and total protein of endometrial cancer cell lines and normal endometrial epithelial cell lines. This study modified silver nanoparticles with iodine and calcium ions and for the first time captured the fingerprints of EMT-related targets microRNA-200a-3p and ZEB1 at the same time without label, and the method has high sensitivity and stability. This SERS-based method has immense potential for elucidating the molecular mechanisms of EMT-related EC, as well as identifying biomarkers for malignant degree and prognosis prediction.

MircoRNA-25-3p in skin precursor cell-induced Schwann cell-derived extracellular vesicles promotes axon regeneration by targeting Tgif1

Nerve injury often leads to severe dysfunction because of the lack of axon regeneration in adult mammal. Intriguingly a series of extracellular vesicles (EVs) have the obvious ability to accelerate the nerve repair. However, the detailed molecular mechanisms to describe that EVs switch neuron from a transmitter to a regenerative state have not been elucidated. This study elucidated the microRNA (miRNA) expression profiles of two types of EVs that promote nerve regeneration. The functions of these miRNAs were screened in vitro. Among the 12 overlapping miRNAs, miR-25-3p was selected for further analysis as it markedly promoted axon regeneration both in vivo and in vitro. Furthermore, knockdown experiments confirmed that PTEN and Klf4, which are the major inhibitors of axon regeneration, were the direct targets of miR-25-3p in dorsal root ganglion (DRG) neurons. The utilization of luciferase reporter assays and functional tests provided evidence that miR-25-3p enhances axon regeneration by targeting Tgif1. Additionally, miR-25-3p upregulated the phosphorylation of Erk. Furthermore, Rapamycin modulated the expression of miR-25-3p in DRG neurons. Finally, the pro-axon regeneration effects of EVs were confirmed by overexpressing miR-25-3p and Tgif1 knockdown in the optic nerve crush model. Thus, the enrichment of miR-25-3p in EVs suggests that it regulates axon regeneration, proving a potential cell-free treatment strategy for nerve injury.

The impact of ribosome biogenesis in cancer: from proliferation to metastasis

The dysregulation of ribosome biogenesis is a hallmark of cancer, facilitating the adaptation to altered translational demands essential for various aspects of tumor progression. This review explores the intricate interplay between ribosome biogenesis and cancer development, highlighting dynamic regulation orchestrated by key oncogenic signaling pathways. Recent studies reveal the multifaceted roles of ribosomes, extending beyond protein factories to include regulatory functions in mRNA translation. Dysregulated ribosome biogenesis not only hampers precise control of global protein production and proliferation but also influences processes such as the maintenance of stem cell-like properties and epithelial-mesenchymal transition, contributing to cancer progression. Interference with ribosome biogenesis, notably through RNA Pol I inhibition, elicits a stress response marked by nucleolar integrity loss, and subsequent G1-cell cycle arrest or cell death. These findings suggest that cancer cells may rely on heightened RNA Pol I transcription, rendering ribosomal RNA synthesis a potential therapeutic vulnerability. The review further explores targeting ribosome biogenesis vulnerabilities as a promising strategy to disrupt global ribosome production, presenting therapeutic opportunities for cancer treatment.

Inhibiting HSD17B8 suppresses the cell proliferation caused by PTEN failure

Loss of the tumor suppressor PTEN homolog daf-18 in Caenorhabditis elegans (C. elegans) triggers diapause cell division during L1 arrest. While prior studies have delved into established pathways, our investigation takes an innovative route. Through forward genetic screening in C. elegans, we pinpoint a new player, F12E12.11, regulated by daf-18, impacting cell proliferation independently of PTEN's typical phosphatase activity. F12E12.11 is an ortholog of human estradiol 17-beta-dehydrogenase 8 (HSD17B8), which converts estradiol to estrone through its NAD-dependent 17-beta-hydroxysteroid dehydrogenase activity. We found that PTEN engages in a physical interplay with HSD17B8, introducing a distinctive suppression mechanism. The reduction in estrone levels and accumulation of estradiol may arrest tumor cells in the G2/M phase of the cell cycle through MAPK/ERK. Our study illuminates an unconventional protein interplay, providing insights into how PTEN modulates tumor suppression by restraining cell division through intricate molecular interactions.

miR-21-Mediated Endothelial Senescence and Dysfunction Are Involved in Cigarette Smoke-Induced Pulmonary Hypertension through Activation of PI3K/AKT/mTOR Signaling

Smoking is a pathogenic factor for pulmonary hypertension (PH). Our previous study showed that serum miR-21 levels are elevated in smokers. miR-21 is considered as engaged in the PH process; however, its mechanisms remain unclear. In this investigation, we found that in the lung tissue of smoking-induced PH patients, the levels of miR-21 and aging markers (p21 and p16) were upregulated, and the function of pulmonary vascular endothelial cells was also impaired. Exposure of mice to cigarette smoke (CS) for four months caused similar changes in lung tissues and increased pulmonary arterial pressure, which were attenuated by knockout of miR-21. Further, human umbilical vein endothelial cells (HUVECs) exposed to cigarette smoke extract (CSE) revealed upregulation of miR-21 levels, depression of PTEN, activation of PI3K/AKT/mTOR signaling, an increase in senescence indexes, and enhanced dysfunction. Inhibiting miR-21 overexpression reversed the PTEN-mTOR signaling pathway and prevented senescence and dysfunction of HUVECs. In sum, our data indicate that miR-21-mediated endothelial senescence and dysfunction are involved in CS-induced PH through the activation of PI3K/AKT/mTOR signaling, which suggests that selective miR-21 inhibition offers the potential to attenuate PH.

Role of Exosomes in Cancer and Aptamer-Modified Exosomes as a Promising Platform for Cancer Targeted Therapy

Exosomes are increasingly recognized as important mediators of intercellular communication in cancer biology. Exosomes can be derived from cancer cells as well as cellular components in tumor microenvironment. After secretion, the exosomes carrying a wide range of bioactive cargos can be ingested by local or distant recipient cells. The released cargos act through a variety of mechanisms to elicit multiple biological effects and impact most if not all hallmarks of cancer. Moreover, owing to their excellent biocompatibility and capability of being easily engineered or modified, exosomes are currently exploited as a promising platform for cancer targeted therapy. In this review, we first summarize the current knowledge of roles of exosomes in risk and etiology, initiation and progression of cancer, as well as their underlying molecular mechanisms. The aptamer-modified exosome as a promising platform for cancer targeted therapy is then briefly introduced. We also discuss the future directions for emerging roles of exosome in tumor biology and perspective of aptamer-modified exosomes in cancer therapy.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

DDR2 signaling and mechanosensing orchestrate neuroblastoma cell fate through different transcriptome mechanisms

The extracellular matrix (ECM) regulates carcinogenesis by interacting with cancer cells via cell surface receptors. Discoidin Domain Receptor 2 (DDR2) is a collagen-activated receptor implicated in cell survival, growth, and differentiation. Dysregulated DDR2 expression has been identified in various cancer types, making it as a promising therapeutic target. Additionally, cancer cells exhibit mechanosensing abilities, detecting changes in ECM stiffness, which is particularly important for carcinogenesis given the observed ECM stiffening in numerous cancer types. Despite these, whether collagen-activated DDR2 signaling and ECM stiffness-induced mechanosensing exert similar effects on cancer cell behavior and whether they operate through analogous mechanisms remain elusive. To address these questions, we performed bulk RNA sequencing (RNA-seq) on human SH-SY5Y neuroblastoma cells cultured on collagen-coated substrates. Our results show that DDR2 downregulation induces significant changes in the cell transcriptome, with changes in expression of 15% of the genome, specifically affecting the genes associated with cell division and differentiation. We validated the RNA-seq results by showing that DDR2 knockdown redirects the cell fate from proliferation to senescence. Like DDR2 knockdown, increasing substrate stiffness diminishes cell proliferation. Surprisingly, RNA-seq indicates that substrate stiffness has no detectable effect on the transcriptome. Furthermore, DDR2 knockdown influences cellular responses to substrate stiffness changes, highlighting a crosstalk between these two ECM-induced signaling pathways. Based on our results, we propose that the ECM could activate DDR2 signaling and mechanosensing in cancer cells to orchestrate their cell fate through distinct mechanisms, with or without involving gene expression, thus providing novel mechanistic insights into cancer progression.

Cellular functions, molecular signalings and therapeutic applications: Translational potential of deubiquitylating enzyme USP9X as a drug target in cancer treatment

Protein ubiquitination, one of the most significant post-translational modifications, plays an important role in controlling the proteins activity in diverse cellular processes. The reversible process of protein ubiquitination, known as deubiquitination, has emerged as a critical mechanism for maintaining cellular homeostasis. The deubiquitinases (DUBs), which participate in deubiquitination process are increasingly recognized as potential candidates for drug discovery. Among these DUBs, ubiquitin-specific protease 9× (USP9X), a highly conserved member of the USP family, exhibits versatile functions in various cellular processes, including the regulation of cell cycle, protein endocytosis, apoptosis, cell polarity, immunological microenvironment, and stem cell characteristics. The dysregulation and abnormal activities of USP9X are influenced by intricate cellular signaling pathway crosstalk and upstream non-coding RNAs. The complex expression patterns and controversial clinical significance of USP9X in cancers suggest its potential as a prognostic biomarker. Furthermore, USP9X inhibitors has shown promising antitumor activity and holds the potential to overcome therapeutic resistance in preclinical models. However, a comprehensive summary of the role and molecular functions of USP9X in cancer progression is currently lacking. In this review, we provide a comprehensive delineation of USP9X participation in numerous critical cellular processes, complicated signaling pathways within the tumor microenvironment, and its potential translational applications to combat therapeutic resistance. By systematically summarizing the updated molecular mechanisms of USP9X in cancer biology, this review aims to contribute to the advancement of cancer therapeutics and provide essential insights for specialists and clinicians in the development of improved cancer treatment strategies.

Bortezomib in previously treated phosphatase and tension homology-deficient patients with advanced intrahepatic cholangiocarcinoma: An open-label, prospective and single-centre phase II trial

INTRODUCTION

Intrahepatic cholangiocarcinoma (ICC) is characterized by a dismal prognosis with limited therapeutic alternatives. To explore phosphatase and tension homolog (PTEN) as a biomarker for proteasome inhibition in ICC, we conducted a phase II trial to assess the second-line efficacy of bortezomib in PTEN-deficient advanced ICC patients.

METHODS

A total of 130 patients with advanced ICC in our centre were screened by PTEN immunohistochemical staining between 1 July 2017, and 31 December 2021, and 16 patients were ultimately enrolled and treated with single-agent bortezomib 1.3 mg/m2 on days 1, 4, 8 and 11 of a 21-day cycle. The primary endpoint was the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors v1.1.

RESULTS

The median follow-up was 6.55 months (95% confidence interval [CI]: 0.7-19.9 months). Among the 16 enrolled patients, the ORR was 18.75% (3/16) and the disease control rate was 43.75% (7/16). The median progress-free survival was 2.95 months (95% CI: 2.1-5.1 months) and the median overall survival (mOS) was 7.2 months (95% CI: 0.7-21.6 months) in the intent-to-treat-patients. Treatment-related adverse events of any grade were reported in 16 patients, with thrombopenia being the most common toxicity. Patients with PTEN staining scores of 0 were more likely to benefit from bortezomib than those with staining scores > 0.

CONCLUSIONS

Bortezomib yielded an encouraging objective response and a favourable OS as a second-line agent in PTEN-deficient ICC patients. Our findings suggest bortezomib as a promising therapeutic option for patients with PTEN-deficient ICC.

HIGHLIGHTS

There is a limited strategy for the second-line option of intrahepatic cholangiocarcinoma (ICC). This investigator-initiated phase 2 study evaluated bortezomib in ICC patients with phosphatase and tension homology deficiency. The overall response rate was 18.75% and the overall survival was 7.2 months in the intent-to-treat cohort. These results justify further developing bortezomib in ICC patients with PTEN deficiency.

Genomic signatures of exceptional longevity and negligible aging in the long-lived red sea urchin

The red sea urchin (Mesocentrotus franciscanus) is one of the Earth's longest-living animals, reported to live more than 100 years with indeterminate growth, life-long reproduction, and no increase in mortality rate with age. To understand the genetic underpinnings of longevity and negligible aging, we constructed a chromosome-level assembly of the red sea urchin genome and compared it to that of short-lived sea urchin species. Genome-wide syntenic alignments identified chromosome rearrangements that distinguish short- and long-lived species. Expanded gene families in long-lived species play a role in innate immunity, sensory nervous system, and genome stability. An integrated network of genes under positive selection in the red sea urchin was involved in genomic regulation, mRNA fidelity, protein homeostasis, and mitochondrial function. Our results implicated known longevity genes in sea urchin longevity but also revealed distinct molecular signatures that may promote long-term maintenance of tissue homeostasis, disease resistance, and negligible aging.

FBXO32-mediated degradation of PTEN promotes lung adenocarcinoma progression

FBXO32, a member of the F-box protein family, is known to play both oncogenic and tumor-suppressive roles in different cancers. However, the functions and the molecular mechanisms regulated by FBXO32 in lung adenocarcinoma (LUAD) remain unclear. Here, we report that FBXO32 is overexpressed in LUAD compared with normal lung tissues, and high expression of FBXO32 correlates with poor prognosis in LUAD patients. Firstly, we observed with a series of functional experiments that FBXO32 alters the cell cycle and promotes the invasion and metastasis of LUAD cells. We further corroborate our findings using in vivo mouse models of metastasis and confirmed that FBXO32 positively regulates LUAD tumor metastasis. Using a proteomic-based approach combined with computational analyses, we found a positive correlation between FBXO32 and the PI3K/AKT/mTOR pathway, and identified PTEN as a FBXO32 interactor. More important, FBXO32 binds PTEN via its C-terminal substrate binding domain and we also validated PTEN as a bona fide FBXO32 substrate. Finally, we demonstrated that FBXO32 promotes EMT and regulates the cell cycle by targeting PTEN for proteasomal-dependent degradation. In summary, our study highlights the role of FBXO32 in promoting the PI3K/AKT/mTOR pathway via PTEN degradation, thereby fostering lung adenocarcinoma progression.

Redox Regulation of Phosphatase and Tensin Homolog by Bicarbonate and Hydrogen Peroxide: Implication of Peroxymonocarbonate in Cell Signaling

Phosphatase and tensin homolog (PTEN) is a negative regulator of the phosphoinositide 3-kinases/protein kinase B (PI3K/AKT) signaling pathway. Notably, its active site contains a cysteine residue that is susceptible to oxidation by hydrogen peroxide (H2O2). This oxidation inhibits the phosphatase function of PTEN, critically contributing to the activation of the PI3K/AKT pathway. Upon the stimulation of cell surface receptors, the activity of NADPH oxidase (NOX) generates a transient amount of H2O2, serving as a mediator in this pathway by oxidizing PTEN. The mechanism underlying this oxidation, occurring despite the presence of highly efficient and abundant cellular oxidant-protecting and reducing systems, continues to pose a perplexing conundrum. Here, we demonstrate that the presence of bicarbonate (HCO3-) promoted the rate of H2O2-mediated PTEN oxidation, probably through the formation of peroxymonocarbonate (HCO4-), and consequently potentiated the phosphorylation of AKT. Acetazolamide (ATZ), a carbonic anhydrase (CA) inhibitor, was shown to diminish the oxidation of PTEN. Thus, CA can also be considered as a modulator in this context. In essence, our findings consolidate the crucial role of HCO3- in the redox regulation of PTEN by H2O2, leading to the presumption that HCO4- is a signaling molecule during cellular physiological processes.

Dysregulation of deubiquitination in breast cancer

Breast cancer (BC) is a highly frequent malignant tumor that poses a serious threat to women's health and has different molecular subtypes, histological subtypes, and biological features, which act by activating oncogenic factors and suppressing cancer inhibitors. The ubiquitin-proteasome system (UPS) is the main process contributing to protein degradation, and deubiquitinases (DUBs) are reverse enzymes that counteract this process. There is growing evidence that dysregulation of DUBs is involved in the occurrence of BC. Herein, we review recent research findings in BC-associated DUBs, describe their nature, classification, and functions, and discuss the potential mechanisms of DUB-related dysregulation in BC. Furthermore, we present the successful treatment of malignant cancer with DUB inhibitors, as well as analyzing the status of targeting aberrant DUBs in BC.

Tumors Established in a Defective Immune Environment Reprogram the Oncogenic Signaling Pathways to Escalate Tumor Antigenicity

Tumors developed in immunocompromised hosts are more immunogenic. However, few studies have addressed the potential mechanisms underlying the high immunogenicity of tumors found in a suppressed immune system. Therefore, we aimed to elucidate the impacts of the immune system on tumor behaviors and immunogenicity sculpting. A murine colorectal adenocarcinoma cell line, CT26wt, was administrated into immunocompetent (BALB/c) and immunocompromised (NOD.SCID) mice, respectively. On day 11, the CT26 cells slowly progressed in the NOD.SCID mice compared to the BALB/c mice. We then performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) and analyzed the differentially expressed proteins (DEPs). The DEPs participated in numerous oncogenic pathways, PI3K/AKT/mTOR cell signaling, and the silencing of several tumor suppressors, such as PTEN and RBL1, during tumorigenesis. On day 34, the CT26/SCID tumors inversely became malignant counterparts; then the CT26/SCID tumors were harvested and re-inoculated into immunocompetent mice (CT26/SCID-Re tumors) to determine the immunogenicity. The CT26/SCID-Re tumor growth rate significantly decreased. Furthermore, increased infiltrations of dendritic cells and tumor-infiltrating T lymphocytes were found in the CT26/SCID-Re tumors. These findings suggest that immunogenic tumors might express multiple tumor rejection antigens, unlike wild-type tumors, and attract more immune cells, therefore decreasing the growth rate. Collectively, our study first revealed that in immunodeficient hosts, tumor suppressors were silenced and oncogenic signaling pathways were changed during the initial phase of tumor development. With tumor progression, the tumor antigens were overexpressed, exhibiting elevated immunogenicity. This study offers a hint on the mechanisms of tumorigenesis and provides a niche for investigating the interaction between host immunity and cancer development.