p73 - NAV3 axis plays a critical role in suppression of colon cancer metastasis

Identification and clinicopathological analysis of potential p73-regulated biomarkers in colorectal cancer via integrative bioinformatics

This study aims to decipher crucial biomarkers regulated by p73 for the early detection of colorectal cancer (CRC) by employing a combination of integrative bioinformatics and expression profiling techniques. The transcriptome profile of HCT116 cell line p53- / - p73+ / + and p53- / - p73 knockdown was performed to identify differentially expressed genes (DEGs). This was corroborated with three CRC tissue expression datasets available in Gene Expression Omnibus. Further analysis involved KEGG and Gene ontology to elucidate the functional roles of DEGs. The protein-protein interaction (PPI) network was constructed using Cytoscape to identify hub genes. Kaplan-Meier (KM) plots along with GEPIA and UALCAN database analysis provided the insights into the prognostic and diagnostic significance of these hub genes. Machine/deep learning algorithms were employed to perform TNM-stage classification. Transcriptome profiling revealed 1289 upregulated and 1897 downregulated genes. When intersected with employed CRC datasets, 284 DEGs were obtained. Comprehensive analysis using gene ontology and KEGG revealed enrichment of the DEGs in metabolic process, fatty acid biosynthesis, etc. The PPI network constructed using these 284 genes assisted in identifying 20 hub genes. Kaplan-Meier, GEPIA, and UALCAN analyses uncovered the clinicopathological relevance of these hub genes. Conclusively, the deep learning model achieved TNM-stage classification accuracy of 0.78 and 0.75 using 284 DEGs and 20 hub genes, respectively. The study represents a pioneer endeavor amalgamating transcriptomics, publicly available tissue datasets, and machine learning to unveil key CRC-associated genes. These genes are found relevant regarding the patients' prognosis and diagnosis. The unveiled biomarkers exhibit robustness in TNM-stage prediction, thereby laying the foundation for future clinical applications and therapeutic interventions in CRC management.

Neuron navigators: A novel frontier with physiological and pathological implications

Neuron navigators are microtubule plus-end tracking proteins containing basic and serine rich regions which are encoded by neuron navigator genes (NAVs). Neuron navigator proteins are essential for neurite outgrowth, neuronal migration, and overall neurodevelopment along with some other functions as well. The navigator proteins are substantially expressed in the developing brain and have been reported to be differentially expressed in various tissues at different ages. Over the years, the research has found neuron navigators to be implicated in a spectrum of pathological conditions such as developmental anomalies, neurodegenerative disorders, neuropathic pain, anxiety, cancers, and certain inflammatory conditions. The existing knowledge about neuron navigators remains sparse owing to their differential functions, undiscovered modulators, and unknown molecular mechanisms. Investigating the possible role of neuron navigators in various physiological processes and pathological conditions pose as a novel field that requires extensive research and might provide novel mechanistic insights and understanding of these aspects.

Wavelet scattering networks in deep learning for discovering protein markers in a cohort of Swedish rectal cancer patients

BACKGROUND

Cancer biomarkers play a pivotal role in the diagnosis, prognosis, and treatment response prediction of the disease. In this study, we analyzed the expression levels of RhoB and DNp73 proteins in rectal cancer, as captured in immunohistochemical images, to predict the 5-year survival time of two patient groups: one with preoperative radiotherapy and one without.

METHODS

The utilization of deep convolutional neural networks in medical research, particularly in clinical cancer studies, has been gaining substantial attention. This success primarily stems from their ability to extract intricate image features that prove invaluable in machine learning. Another innovative method for extracting features at multiple levels is the wavelet-scattering network. Our study combines the strengths of these two convolution-based approaches to robustly extract image features related to protein expression.

RESULTS

The efficacy of our approach was evaluated across various tissue types, including tumor, biopsy, metastasis, and adjacent normal tissue. Statistical assessments demonstrated exceptional performance across a range of metrics, including prediction accuracy, classification accuracy, precision, and the area under the receiver operating characteristic curve.

CONCLUSION

These results underscore the potential of dual convolutional learning to assist clinical researchers in the timely validation and discovery of cancer biomarkers.

Tumour Suppressor Neuron Navigator 3 and Matrix Metalloproteinase 14 are Co-expressed in Most Melanomas but Downregulated in Thick Tumours

Melanoma is a highly metastatic tumour originating from neural crest-derived melanocytes. The aim of this study was to analyse the expression of neuron navigator 3 (NAV3) in relation to membrane type-1 matrix metalloproteinase MMP14, a major regulator of invasion, in 40 primary melanomas, 15 benign naevi and 2 melanoma cell lines. NAV3 copy number changes were found in 18/27 (67%) primary melanomas, so that deletions dominated (16/27 of samples, 59%). NAV3 protein was found to be localized at the leading edge of migrating melanoma cells in vitro. Silencing of NAV3 reduced both melanoma cell migration in 2-dimensional conditions, as well as sprouting in 3-dimensional collagen I. NAV3 protein expression correlated with MMP14 in 26/37 (70%) primary melanomas. NAV3 and MMP14 were co-expressed in all tumours with Breslow thickness < 1 mm, in 11/23 of mid-thickness tumours (1-5 mm), but in only 1/6 samples of thick (> 5 mm) melanomas. Altogether, NAV3 number changes are frequent in melanomas, and NAV3 and MMP14, while expressed in all thin melanomas, are often downregulated in thicker tumours, suggesting that the lack of both NAV3 and MMP14 favours melanoma progression.

The Neuron Navigators: Structure, function, and evolutionary history

Neuron navigators (Navigators) are cytoskeletal-associated proteins important for neuron migration, neurite growth, and axon guidance, but they also function more widely in other tissues. Recent studies have revealed novel cellular functions of Navigators such as macropinocytosis, and have implicated Navigators in human disorders of axon growth. Navigators are present in most or all bilaterian animals: vertebrates have three Navigators (NAV1-3), Drosophila has one (Sickie), and Caenorhabditis elegans has one (Unc-53). Structurally, Navigators have conserved N- and C-terminal regions each containing specific domains. The N-terminal region contains a calponin homology (CH) domain and one or more SxIP motifs, thought to interact with the actin cytoskeleton and mediate localization to microtubule plus-end binding proteins, respectively. The C-terminal region contains two coiled-coil domains, followed by a AAA+ family nucleoside triphosphatase domain of unknown activity. The Navigators appear to have evolved by fusion of N- and C-terminal region homologs present in simpler organisms. Overall, Navigators participate in the cytoskeletal response to extracellular cues via microtubules and actin filaments, in conjunction with membrane trafficking. We propose that uptake of fluid-phase cues and nutrients and/or downregulation of cell surface receptors could represent general mechanisms that explain Navigator functions. Future studies developing new models, such as conditional knockout mice or human cerebral organoids may reveal new insights into Navigator function. Importantly, further biochemical studies are needed to define the activities of the Navigator AAA+ domain, and to study potential interactions among different Navigators and their binding partners.

Personalized targeted therapy prescription in colorectal cancer using algorithmic analysis of RNA sequencing data

Background:

Overall survival of advanced colorectal cancer (CRC) patients remains poor, and gene expression analysis could potentially complement detection of clinically relevant mutations to personalize CRC treatments.

Methods:

We performed RNA sequencing of formalin-fixed, paraffin-embedded (FFPE) cancer tissue samples of 23 CRC patients and interpreted the data obtained using bioinformatic method Oncobox for expression-based rating of targeted therapeutics. Oncobox ranks cancer drugs according to the efficiency score calculated using target genes expression and molecular pathway activation data. The patients had primary and metastatic CRC with metastases in liver, peritoneum, brain, adrenal gland, lymph nodes and ovary. Two patients had mutations in NRAS, seven others had mutated KRAS gene. Patients were treated by aflibercept, bevacizumab, bortezomib, cabozantinib, cetuximab, crizotinib, denosumab, panitumumab and regorafenib as monotherapy or in combination with chemotherapy, and information on the success of totally 39 lines of therapy was collected.

Results:

Oncobox drug efficiency score was effective biomarker that could predict treatment outcomes in the experimental cohort (AUC 0.77 for all lines of therapy and 0.91 for the first line after tumor sampling). Separately for bevacizumab, it was effective in the experimental cohort (AUC 0.87) and in 3 independent literature CRC datasets, n = 107 (AUC 0.84–0.94). It also predicted progression-free survival in univariate (Hazard ratio 0.14) and multivariate (Hazard ratio 0.066) analyses. Difference in AUC scores evidences importance of using recent biosamples for the prediction quality.

Conclusion:

Our results suggest that RNA sequencing analysis of tumor FFPE materials may be helpful for personalizing prescriptions of targeted therapeutics in CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10177-3.

PROM1, CXCL8, RUNX1, NAV1 and TP73 genes as independent markers predictive of prognosis or response to treatment in two cohorts of high-grade serous ovarian cancer patients

Considering the vast biological diversity and high mortality rate in high-grade ovarian cancers, identification of novel biomarkers, enabling precise diagnosis and effective, less aggravating treatment, is of paramount importance. Based on scientific literature data, we selected 80 cancer-related genes and evaluated their mRNA expression in 70 high-grade serous ovarian cancer (HGSOC) samples by Real-Time qPCR. The results were validated in an independent Northern American cohort of 85 HGSOC patients with publicly available NGS RNA-seq data. Detailed statistical analyses of our cohort with multivariate Cox and logistic regression models considering clinico-pathological data and different TP53 mutation statuses, revealed an altered expression of 49 genes to affect the prognosis and/or treatment response. Next, these genes were investigated in the validation cohort, to confirm the clinical significance of their expression alterations, and to identify genetic variants with an expected high or moderate impact on their products. The expression changes of five genes, PROM1, CXCL8, RUNX1, NAV1, TP73, were found to predict prognosis or response to treatment in both cohorts, depending on the TP53 mutation status. In addition, we revealed novel and confirmed known SNPs in these genes, and showed that SNPs in the PROM1 gene correlated with its elevated expression.

Chromogenic in Situ-Hybridization of HPV16/18 DNA in Relation to the Over-Expressed Protein of P73-Gene in Tissues from a Group of Thyroid Carcinoma

Thyroid cancer has been related to many environmental, genetic, and viral factors. Human Papilloma Viruses (HPV) are epitheliotropic viruses infecting cutaneous and mucosal tissues, leading to a variety of benign and malignant tumors. The p73-gene expresses two important isoforms from the N-terminal end with two opposite activities in the regulation of cell fate. The present study aimed to assess the histopathological expression of tissues from thyroid cancers in relation to the over-expression of the p73 gene with HPV 16/18 infection. A total of 116 thyroid tissues were examined for HPV 16/18-DNA and P73-gene protein expression. The samples belonged to 36 patients diagnosed with thyroid carcinoma, 40 thyroid adenoma tissues blocks, and 40 apparently normal thyroid tissues. The detection of HPV 16/18-DNA was performed by in situ hybridization (ISH), whereas P73 gene expression was carried out by immunohistochemistry (IHC). The HPV16/18 DNA-ISH reactions in thyroid cancers were found in 72.2% tissues, 35% HPV16/18- positivity was detected in the thyroid adenoma tissues group, and 27.5% of healthy thyroid tissues revealed ISH reactions. Statistically, the difference of the HPV16/18 in thyroid cancers and control was highly significant. The p73 was detected in 66.7% and 57.5% of thyroid cancer and adenoma thyroid tissues, respectively, while 45% of the examined healthy thyroid tissues revealed IHC-reactions. The difference between the p73-protein expression percentages detected in tissues of thyroid tumors and the control group was non statistically significant. The presence of HPV16/18, as well as an over-expressed p73-gene, in thyroid cancer patients, suggests that the virus, as well as this protein, may play an etiologic role in thyroid carcinogenesis.

NAV3 Is a Novel Prognostic Biomarker Affecting the Immune Status of the Tumor Microenvironment in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignant tumors in the world. Tumor microenvironment (TME) plays a crucial role in the development of CRC. With the deep understanding of TME function, growing studies have demonstrated that alteration in tumor-infiltrating immune cells (TICs) and gene expressions are associated with clinical outcomes of various tumors. In this study, we aimed to recognize critical prognostic genes involved in immune states in TME of CRC. Hence, the proportion of TICs and the number of immune and stromal components in CRC samples from TCGA datasets were calculated by the use of CIBERSORT and ESTIMATE calculation methods. Different assays were applied to collect differential expression genes (DEGs) shared by the ImmuneScore and StromalScore. DEGs were further analyzed by the use of univariate Cox regression. Our attention focused on neuron navigator 3 (NAV3) which was highly expressed in CRC specimens and associated with an advanced clinical stage and poor prognosis of CRC patients. KEGG assays revealed that NAV3 may be involved in Alzheimer disease, amyotrophic lateral sclerosis, Huntington disease, FoxO signaling pathway, and human papillomavirus infection. Correlation assays showed that macrophage M0 and B cells memory, NK cells activated, dendritic cells resting, T cells CD4 memory activated, and T cells CD8 were correlated with NAV3 expression, indicating that NAV3 may represent the immune status of TME. Finally, RT-PCR confirmed that NAV3 expression was distinctly increased in CRC cells, and its knockdown suppressed the proliferation of CRC cells. Overall, NAV3 could be used as a novel predictor for TME of CRC and might be a novel prognostic biomarker. In the future, drugs targeting NAV3 might be developed as a potential immunotherapy for CRC patients.

P63 and P73 Activation in Cancers with p53 Mutation

The members of the p53 family comprise p53, p63, and p73, and full-length isoforms of the p53 family have a tumor suppressor function. However, p53, but not p63 or p73, has a high mutation rate in cancers causing it to lose its tumor suppressor function. The top and second-most prevalent p53 mutations are missense and nonsense mutations, respectively. In this review, we discuss possible drug therapies for nonsense mutation and a missense mutation in p53. p63 and p73 activators may be able to replace mutant p53 and act as anti-cancer drugs. Herein, these p63 and p73 activators are summarized and how to improve these activator responses, particularly focusing on p53 gain-of-function mutants, is discussed.

p73-regulated FER1L4 lncRNA sponges the oncogenic potential of miR-1273g-3p and aids in the suppression of colorectal cancer metastasis

p73 belongs to the p53 tumor suppressor family and is involved in the suppression of metastasis. However, its specific mechanism of action remains to be elucidated. Long non-coding RNAs portray a crucial role in tumor suppression. We have identified lncRNA FER1L4 as a p73 transcriptional target. The binding of p73 to FER1L4 promoter was established by bioinformatics analysis, luciferase reporter, and ChIP assays. Both FER1L4 and p73 knockdown enhanced the migration and invasion rate of colorectal cancer cells. FER1L4 also plays a critical role in p73-mediated cell-cycle arrest and apoptosis. FER1L4 sponged the expression of miR-1273g-3p, which, in turn, increased PTEN expression, leading to cell-cycle arrest. RNA in situ hybridization revealed the down-regulation of both p73 and FER1L4 expression in a metastatic colon cancer tissue as compared with non-metastatic tissue. Collectively, we impart conclusive proof that p73 exerts its anti-metastatic properties by inducing lncRNA FER1L4 in response to genotoxic stress.

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Long non-coding RNA FER1L4 functions as a direct transcriptional target of p73

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FER1L4 plays a pivotal role in p73-mediated cell-cycle arrest and apoptosis

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FER1L4kd augments colorectal cancer cell proliferation in a p73-dependent manner

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p73-FER1L4 axis sponges miR-1273g-3p and inhibits its oncogenic role

Survival stratification for colorectal cancer via multi-omics integration using an autoencoder-based model

Prognosis stratification in colorectal cancer helps to address cancer heterogeneity and contributes to the improvement of tailored treatments for colorectal cancer patients. In this study, an autoencoder-based model was implemented to predict the prognosis of colorectal cancer via the integration of multi-omics data. DNA methylation, RNA-seq, and miRNA-seq data from The Cancer Genome Atlas (TCGA) database were integrated as input for the autoencoder, and 175 transformed features were produced. The survival-related features were used to cluster the samples using k-means clustering. The autoencoder-based strategy was compared to the principal component analysis (PCA)-, t-distributed random neighbor embedded (t-SNE)-, non-negative matrix factorization (NMF)-, or individual Cox proportional hazards (Cox-PH)-based strategies. Using the 175 transformed features, tumor samples were clustered into two groups (G1 and G2) with significantly different survival rates. The autoencoder-based strategy performed better at identifying survival-related features than the other transformation strategies. Further, the two survival groups were robustly validated using "hold-out" validation and five validation cohorts. Gene expression profiles, miRNA profiles, DNA methylation, and signaling pathway profiles varied from the poor prognosis group (G2) to the good prognosis group (G1). miRNA-mRNA networks were constructed using six differentially expressed miRNAs (let-7c, mir-34c, mir-133b, let-7e, mir-144, and mir-106a) and 19 predicted target genes. The autoencoder-based computational framework could distinguish good prognosis samples from bad prognosis samples and facilitate a better understanding of the molecular biology of colorectal cancer.

Dual Role of p73 in Cancer Microenvironment and DNA Damage Response

Understanding the mechanisms that regulate cancer progression is pivotal for the development of new therapies. Although p53 is mutated in half of human cancers, its family member p73 is not. At the same time, isoforms of p73 are often overexpressed in cancers and p73 can overtake many p53 functions to kill abnormal cells. According to the latest studies, while p73 represses epithelial–mesenchymal transition and metastasis, it can also promote tumour growth by modulating crosstalk between cancer and immune cells in the tumor microenvironment, M2 macrophage polarisation, Th2 T-cell differentiation, and angiogenesis. Thus, p73 likely plays a dual role as a tumor suppressor by regulating apoptosis in response to genotoxic stress or as an oncoprotein by promoting the immunosuppressive environment and immune cell differentiation.

Mechanisms of Functional Pleiotropy of p73 in Cancer and Beyond

The transcription factor p73 is a structural and functional homolog of TP53, the most famous and frequently mutated tumor-suppressor gene. The TP73 gene can synthesize an overwhelming number of isoforms via splicing events in 5′ and 3′ ends and alternative promoter usage. Although it originally came into the spotlight due to the potential of several of these isoforms to mimic p53 functions, it is now clear that TP73 has its own unique identity as a master regulator of multifaceted processes in embryonic development, tissue homeostasis, and cancer. This remarkable functional pleiotropy is supported by a high degree of mechanistic heterogeneity, which extends far-beyond the typical mode of action by transactivation and largely relies on the ability of p73 isoforms to form protein–protein interactions (PPIs) with a variety of nuclear and cytoplasmic proteins. Importantly, each p73 isoform carries a unique combination of functional domains and residues that facilitates the establishment of PPIs in a highly selective manner. Herein, we summarize the expanding functional repertoire of TP73 in physiological and oncogenic processes. We emphasize how TP73’s ability to control neurodevelopment and neurodifferentiation is co-opted in cancer cells toward neoneurogenesis, an emerging cancer hallmark, whereby tumors promote their own innervation. By further exploring the canonical and non-canonical mechanistic patterns of p73, we apprehend its functional diversity as the result of a sophisticated and coordinated interplay of: (a) the type of p73 isoforms (b) the presence of p73 interaction partners in the cell milieu, and (c) the architecture of target gene promoters. We suppose that dysregulation of one or more of these parameters in tumors may lead to cancer initiation and progression by reactivating p73 isoforms and/or p73-regulated differentiation programs thereof in a spatiotemporally inappropriate manner. A thorough understanding of the mechanisms supporting p73 functional diversity is of paramount importance for the efficient and precise p73 targeting not only in cancer, but also in other pathological conditions where TP73 dysregulation is causally involved.

Genomic Analysis of Response to Neoadjuvant Chemotherapy in Esophageal Adenocarcinoma

Neoadjuvant therapy followed by surgery is the standard of care for locally advanced esophageal adenocarcinoma (EAC). Unfortunately, response to neoadjuvant chemotherapy (NAC) is poor (20-37%), as is the overall survival benefit at five years (9%). The EAC genome is complex and heterogeneous between patients, and it is not yet understood whether specific mutational patterns may result in chemotherapy sensitivity or resistance. To identify associations between genomic events and response to NAC in EAC, a comparative genomic analysis was performed in 65 patients with extensive clinical and pathological annotation using whole-genome sequencing (WGS). We defined response using Mandard Tumor Regression Grade (TRG), with responders classified as TRG1-2 (n = 27) and non-responders classified as TRG4-5 (n =38). We report a higher non-synonymous mutation burden in responders (median 2.08/Mb vs. 1.70/Mb, p = 0.036) and elevated copy number variation in non-responders (282 vs. 136/patient, p < 0.001). We identified copy number variants unique to each group in our cohort, with cell cycle (CDKN2A, CCND1), c-Myc (MYC), RTK/PIK3 (KRAS, EGFR) and gastrointestinal differentiation (GATA6) pathway genes being specifically altered in non-responders. Of note, NAV3 mutations were exclusively present in the non-responder group with a frequency of 22%. Thus, lower mutation burden, higher chromosomal instability and specific copy number alterations are associated with resistance to NAC.

Plasma Exosomal miRNA Levels after Radiotherapy Are Associated with Early Progression and Metastasis of Cervical Cancer: A Pilot Study

Plasma exosomal miRNAs are key regulators of cell-cell interactions associated with several biological functions in patients with cancer. This pilot study aimed to investigate the log₂ fold change (log₂FC) of the expression of exosomal miRNAs and related mRNAs in the blood of patients with cervical cancer to identify prognostic markers better than those currently available. We sequenced plasma exosomal RNA from 56 blood samples collected from 28 patients with cervical cancer, who had been treated with concurrent chemoradiotherapy (CCRT). Changes in the expression of miRNAs and mRNAs before and after CCRT were represented as log₂FC. Their biological functions were studied by miRNA-mRNA network analysis, using ingenuity pathway analysis, after the selection of two groups of miRNAs, each associated with early progression (EP) and metastasis, also described as initial stage. Seven patients experienced EP, three of whom died within four months after progression. Reduced levels of miR-1228-5p, miR-33a-5p, miR-3200-3p, and miR-6815-5p and increased levels of miR-146a-3p in patients with EP revealed unresolved inflammation, with accompanying increased expression of PCK1 and decreased expression of FCGR1A. Increased levels of miR-605-5p, miR-6791-5p, miR-6780a-5p, and miR-6826-5p and decreased levels of miR-16-1-3p (or 15a-3p) were associated with the degree of metastasis and led to the systemic activation of myeloid, endothelial, and epithelial cells, as well as neurons, phagocytes, and platelets. Log₂FCs in the expression of miRNAs and mRNAs from plasma exosomes after CCRT are associated with EP and metastasis, reflecting unresolved inflammation and systemic microenvironmental factors, respectively. However, this study, supported by preliminary data insufficient to reach clear conclusions, should be verified in larger prospective cohorts.

microRNA-939 Promotes the Vitality of Human Breast Cancer Cells via Inhibition of E2F1/P73 Signaling

We assessed miR-939’s role in breast cancer (BC) and its molecular mechanism. PCR was performed to detect miRNA levels. Correlations between miR-939 and patients’ pathological information were analyzed. After transfection of E2F1 plasmid, P73 plasmid, si-E2F1, si-P73, miR-939 mimic or si-miR-939, cell proliferation and apoptosis were measured. The miR-939 target gene was proved by a luciferase assay. Protein and mRNA levels of E2F1 and P73 were detected by immunoblotting and PCR, and corresponding proliferation or apoptosis were assessed. MiR-939 expression was significantly increased in BC and associated with TNM staging, Ki-67 enhancement, and shorter disease-free survival time. In BC clinical samples, E2F1 expression is negatively correlated with miR-939 expressions. Overexpressing miR-939 stimulated growth but suppressed cell apoptosis. Functional analysis indicated E2F1 is the target gene of miR-939, and overexpression of miR-939 significantly downregulated E2F1 and P73. Silencing of E2F1 or P73 significantly promoted MDA-MB-231 cell proliferation and inhibited apoptosis. Overexpression of E2F1 plasmid or P73 plasmid significantly inhibited MDA-MB-231 cell proliferation but induced apoptosis. Transfection of P73 or E2F1 plasmid abolished miR-939’s effects on proliferation and apoptosis. miR-939 promotes breast cancer progression by downregulation of E2F1 to inhibit P73 pathway, thereby promoting proliferation and inhibiting apoptosis.

SOX9 is required for kidney fibrosis and activates NAV3 to drive renal myofibroblast function

Renal fibrosis is a common end point for kidney injury and many chronic kidney diseases. Fibrogenesis depends on the sustained activation of myofibroblasts, which deposit the extracellular matrix that causes progressive scarring and organ failure. Here, we showed that the transcription factor SOX9 was associated with kidney fibrosis in humans and required for experimentally induced kidney fibrosis in mice. From genome-wide analysis, we identified Neuron navigator 3 (NAV3) as acting downstream of SOX9 in kidney fibrosis. NAV3 increased in abundance and colocalized with SOX9 after renal injury in mice, and both SOX9 and NAV3 were present in diseased human kidneys. In an in vitro model of renal pericyte transdifferentiation into myofibroblasts, we demonstrated that NAV3 was required for multiple aspects of fibrogenesis, including actin polymerization linked to cell migration and sustained activation of the mechanosensitive transcription factor YAP1. In summary, our work identifies a SOX9-NAV3-YAP1 axis involved in the progression of kidney fibrosis and points to NAV3 as a potential target for pharmacological intervention.

Pirh2, an E3 ligase, regulates the AIP4-p73 regulatory pathway by modulating AIP4 expression and ubiquitination

Pirh2 is an E3 ligase belonging to the RING-H2 family and shown to bind, ubiquitinate and downregulate p73 tumor suppressor function without altering p73 protein levels. AIP4, an E3 ligase belonging to the HECT domain family, has been reported to be a negative regulatory protein that promotes p73 ubiquitination and degradation. Herein, we found that Pirh2 is a key regulator of AIP4 that inhibits p73 function. Pirh2 physically interacts with AIP4 and significantly downregulates AIP4 expression. This downregulation is shown to involve the ubiquitination of AIP4 by Pirh2. Importantly, we demonstrated that the ectopic expression of Pirh2 inhibits the AIP4-p73 negative regulatory pathway, which was restored when depleting endogenous Pirh2 utilizing Pirh2-siRNAs. We further observed that Pirh2 decreases AIP4-mediated p73 ubiquitination. At the translational level and specifically regarding p73 cell cycle arrest function, Pirh2 still ensures the arrest of p73-mediated G1 despite AIP4 expression. Our study reveals a novel link between two E3 ligases previously thought to be unrelated in regulating the same effector substrate, p73. These findings open a gateway to explain how E3 ligases differentiate between regulating multiple substrates that may belong to the same family of proteins, as it is the case for the p53 and p73 proteins.

NETO2 Is Deregulated in Breast, Prostate, and Colorectal Cancer and Participates in Cellular Signaling

The NETO2 gene (neuropilin and tolloid-like 2) encodes a protein that acts as an accessory subunit of kainate receptors and is predominantly expressed in the brain. Upregulation of NETO2 has been observed in several tumors; however, its role in tumorigenesis remains unclear. In this study, we investigated NETO2 expression in breast, prostate, and colorectal cancer using quantitative PCR (qPCR), as well as the effect of shRNA-mediated NETO2 silencing on transcriptome changes in colorectal cancer cells. In the investigated tumors, we observed both increased and decreased NETO2 mRNA levels, presenting no correlation with the main clinicopathological characteristics. In HCT116 cells, NETO2 knockdown resulted in the differential expression of 17 genes and 2 long non-coding RNAs (lncRNAs), associated with the upregulation of circadian rhythm and downregulation of several cancer-associated pathways, including Wnt, transforming growth factor (TGF)-β, Janus kinase (JAK)-signal transducer and activator of transcription (STAT), mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathways. Furthermore, we demonstrated the possibility to utilize a novel model organism, short-lived fish Nothobranchius furzeri, for evaluating NETO2 functions. The ortholog neto2b in N. furzeri demonstrated a high similarity in nucleotide and amino acid sequences with human NETO2, as well as was characterized by stable expression in various fish tissues. Collectively, our findings demonstrate the deregulation of NETO2 in the breast, prostate, and colorectal cancer and its participation in the tumor development primarily through cellular signaling.

A HGF‑derived peptide suppresses EMT in human lens epithelial cells via the TGF‑β/Smad and Akt/mTOR signaling pathways

Posterior capsule opacification (PCO) as a result of proliferation and fibrogenesis of lens epithelial cells (LECs) is the most frequent long‑term complication of modern cataract surgery. LECs may undergo epithelial‑mesenchymal transition (EMT) that resembles the morphological and molecular characteristics of PCO. A pre‑identified novel, hepatocyte growth factor (HGF)‑derived peptide H‑RN, was reported to exhibit anti‑angiogenic activity and anti‑inflammatory effects in ocular cells both in vitro and in vivo. However, the role of H‑RN in the promotion of the development of EMT in LECs is unknown. In the present study, the effects of H‑RN on the development of EMT induced by transforming growth factor (TGF)‑β in human LECs, and the possible signaling pathways participating in this process were investigated. The results showed that H‑RN promoted the expression of the EMT‑associated markers, α‑smooth muscle actin and fibronectin, whereas the expression of E‑cadherin and connexin 43 were reduced. The morphological changes typically associated with EMT seen in LECs induced by TGF‑β2 were inhibited by H‑RN, which was consistent with the effects of a TGF‑β2 inhibitor, SB431542. Smad2 and Smad3 phosphorylation induced by TGF‑β2 were reduced by H‑RN, and phosphorylation of Akt, mTOR and P70S6K induced by TGF‑β2 were also notably reduced by H‑RN in LECs. Therefore, the results of the present study showed that H‑RN treatment significantly suppressed the development of EMT induced by TGF‑β2, at least partially through the TGF‑β/Smad and Akt/mTOR signaling pathways in human LECs. The present study highlights that H‑RN, a novel HGF‑derived peptide, may be a novel therapeutic agent for prevention and treatment of PCO.