Proteasome-dependent degradation of Smad7 is critical for lung cancer metastasis

Downregulated PSME3 Contributes to Severe Preeclampsia by Promoting Trophoblast Cell Apoptosis

BACKGROUND

Severe preeclampsia (sPE) is a serious condition posing risks to both maternal and fetal health. Based on mass spectrometry analysis, we identified a key protein, PSME3 (proteasome activator subunit 3), an 11S proteasome activator, whose protein level was significantly downregulated in sPE placentas and whose function in sPE remains unknown.

METHODS

PSME3 protein levels in human placental tissue were detected using Western blot, and PSME3 concentration in serum was detected by ELISA assay. The human preeclampsia-like phenotypes of Psme3-/- pregnant mice were examined. Trophoblast cell apoptosis was detected by flow cytometry. Pregnant mice were treated with 9.5% O2 to construct a preeclampsia mouse model for detecting placental Psme3 expression. The regulation of PSME3 expression by hypoxia was detected in trophoblast cell lines treated with 21% O2 or 1% O2.

RESULTS

PSME3 protein levels were significantly downregulated in sPE placentas and serum. Pregnant mice with Psme3-/- embryos and placentas spontaneously presented human preeclampsia-like symptoms, including hypertension and proteinuria, increased serum soluble fms-like tyrosine kinase 1 concentration, fetal growth restriction, and increased cellular apoptosis. Mechanically, PSME3 knockdown promoted the apoptosis of trophoblast cells by repressing the degradation of UBE2V2 (ubiquitin conjugating enzyme E2 V2). Moreover, the placentas of hypoxia-induced preeclampsia mice presented significantly reduced Psme3 protein levels and elevated Ube2v2 protein levels. Hypoxia-inducible factor-1α functioned as a transcriptional repressor of PSME3.

CONCLUSIONS

In sPE placentas, hypoxia of the placenta may lead to the transcriptional inhibition of PSME3. PSME3 deficiency promotes the accumulation of UBE2V2, thereby inducing trophoblast cell apoptosis. Our study provides a new perspective for elucidating the pathogenesis of sPE.

REGγ is essential to maintain bone homeostasis by degrading TRAF6, preventing osteoporosis

Primary osteoporosis, manifesting as decreased bone mass and increased bone fragility, is a "silent disease" that is often ignored until a bone breaks. Accordingly, it is urgent to develop reliable biomarkers and novel therapeutic strategies for osteoporosis treatment. Here, we identified REGγ as a potential biomarker of osteoporotic populations through proteomics analysis. Next, we demonstrated that REGγ deficiency increased osteoclast activity and triggered bone mass loss in REGγ knockout (KO) and bone marrow-derive macrophage (BMM)-conditional REGγ KO mice. However, the osteoclast activity decreased in BMM-conditional REGγ overexpression mice. Mechanistically, we defined that REGγ-20S proteasome directly degraded TRAF6 to inhibit bone absorption in a ubiquitin-independent pathway. More importantly, BMM-conditional Traf6 KO with REGγ KO mice could "rescue" the osteoporosis phenotypes. Based on NIP30 (a REGγ "inhibitor") dephosphorylation by CKII inhibition activated the ubiquitin-independent degradation of TRAF6, we selected TTP22, an inhibitor of CKII, and defined that TTP22 could alleviate osteoporosis in vitro and in vivo. Overall, our study reveals a unique function of NIP30/REGγ/TRAF6 axis in osteoporosis and provides a potential therapeutic drug TTP22 for osteoporosis.

Azobenzene-Tagged Photopeptides Exhibiting Excellent Selectivity and Light-Induced Cytotoxicity in MCF-7 Cells over HeLa and A549

The precise regulation of proteasome activity has become a focal point in current research, particularly its implications in cancer treatment. Bortezomib is used for treating multiple myeloma and is found to be ineffective against solid tumors. A spatiotemporal control over the proteasome is one of the solutions to resolve these issues using external stimuli, such as light. Thus, we designed and synthesized azobenzene-containing tripeptide vinyl sulfones 1, 2, 3, and 4, as the azobenzene moiety can impart E↔Z isomerism upon exposure to UV light. Further, the hydrophobicity of these peptides was fine-tuned by systematically varying the size of hydrophobic amino acids at the P1, P2, and P3 positions. The light-induced Z isomers of these photopeptides showed excellent cellular potency in HeLa, MCF-7, and A549 cell lines. Photopeptide 4 with valine at the proximal position, phenylalanine at P2, and leucine at the P1 positions exhibited 19.3- and 6.6-fold cellular potency in MCF-7 and A549 cells, respectively.

PA28γ, the ring that makes tumors invisible to the immune system?

PA28γ is a proteasomal interactor whose main and most known function is to stimulate the hydrolytic activity of the 20 S proteasome independently of ubiquitin and ATP. Unlike its two paralogues, PA28α and PA28β, PA28γ is largely present in the nuclear compartment and plays pivotal functions in important pathways such as cellular division, apoptosis, neoplastic transformation, chromatin structure and organization, fertility, lipid metabolism, and DNA repair mechanisms. Although it is known that a substantial fraction of PA28γ is found in the cell in a free form (i.e. not associated with 20 S), almost all of the studies so far have focused on its ability to modulate proteasomal enzymatic activities. In this respect, the ability of PA28γ to strongly stimulate degradation of proteins, especially if intrinsically disordered and therefore devoid of three-dimensional tightly folded structure, appears to be the main molecular mechanism underlying its multiple biological effects. Initial studies, conducted more than 20 years ago, came to the conclusion that among the many biological functions of PA28γ, the immunological ones were rather limited and circumscribed. In this review, we focus on recent evidence showing that PA28γ fulfills significant functions in cell-mediated acquired immunity, with a particular role in attenuating MHC class I antigen presentation, especially in relation to neoplastic transformation and autoimmune diseases.

Frizzled 6 endows high-grade serous ovarian cancer with stem-like properties and chemoresistance

Stem-like properties contribute to tumor growth, metastasis, and chemoresistance. High-grade serous ovarian cancer (HGSOC) exhibits a very aggressive phenotype characterized by extensive metastasis, rapid progression, and therapy resistance. Frizzled 6 (FZD6) is overexpressed in HGSOC, and higher levels of FZD6 have been associated with shorter survival times in patients with HGSOC. Functionally, FZD6 promotes HGSOC growth and peritoneal metastasis. It endues HGSOC cells with stem-like properties by modulating POU5F1, ALDH1, and EPCAM. It can also desensitize HGSOC cells to certain chemical drugs. As a putative ligand for FZD6, WNT7B is also implicated in cell proliferation, stem-like properties, invasion and migration, and chemoresistance. SMAD7 is a downstream component of FZD6 signaling that is thought to mediate FZD6-associated phenotypes, at least in part. Therefore, FZD6/WNT7B-SMAD7 can be considered a tumor-promoting signaling pathway in HGSOC that may be responsible for tumor growth, peritoneal metastasis, and chemoresistance.

UBASH3B-mediated MRPL12 Y60 dephosphorylation inhibits LUAD development by driving mitochondrial metabolism reprogramming

BACKGROUND

Metabolic reprogramming plays a pivotal role in tumorigenesis and development of lung adenocarcinoma (LUAD). However, the precise mechanisms and potential targets for metabolic reprogramming in LUAD remain elusive. Our prior investigations revealed that the mitochondrial ribosomal protein MRPL12, identified as a novel mitochondrial transcriptional regulatory gene, exerts a critical influence on mitochondrial metabolism. Despite this, the role and regulatory mechanisms underlying MRPL12's transcriptional activity in cancers remain unexplored.

METHODS

Human LUAD tissues, Tp53fl/fl;KrasG12D-driven LUAD mouse models, LUAD patient-derived organoids (PDO), and LUAD cell lines were used to explored the expression and function of MRPL12. The posttranslational modification of MRPL12 was analyzed by mass spectrometry, and the oncogenic role of key phosphorylation sites of MRPL12 in LUAD development was verified in vivo and in vitro.

RESULTS

MRPL12 was upregulated in human LUAD tissues, Tp53fl/fl;KrasG12D-driven LUAD tissues in mice, LUAD PDO, and LUAD cell lines, correlating with poor patient survival. Overexpression of MRPL12 significantly promoted LUAD tumorigenesis, metastasis, and PDO formation, while MRPL12 knockdown elicited the opposite phenotype. Additionally, MRPL12 deletion in a Tp53fl/fl;KrasG12D-driven mouse LUAD model conferred a notable survival advantage, delaying tumor onset and reducing malignant progression. Mechanistically, we discovered that MRPL12 promotes tumor progression by upregulating mitochondrial oxidative phosphorylation. Furthermore, we identified UBASH3B as a specific binder of MRPL12, dephosphorylating tyrosine 60 in MRPL12 (MRPL12 Y60) and inhibiting its oncogenic functions. The decrease in MRPL12 Y60 phosphorylation impeded the binding of MRPL12 to POLRMT, downregulating mitochondrial metabolism in LUAD cells. In-depth in vivo, in vitro, and organoid models validated the inhibitory effect of MRPL12 Y60 mutation on LUAD.

CONCLUSION

This study establishes MRPL12 as a novel oncogene in LUAD, contributing to LUAD pathogenesis by orchestrating mitochondrial metabolism reprogramming towards oxidative phosphorylation (OXPHOS). Furthermore, it confirms Y60 as a specific phosphorylation modification site regulating MRPL12's oncogenic functions, offering insights for the development of LUAD-specific targeted drugs and clinical interventions.

New horizons in the mechanisms and therapeutic strategies for PD-L1 protein degradation in cancer

Programmed death-ligand 1 (PD-L1) has become a crucial focus in cancer immunotherapy considering it is found in many different cells. Cancer cells enhance the suppressive impact of programmed death receptor 1 (PD-1) through elevating PD-L1 expression, which allows them to escape immune detection. Although there have been significant improvements, the effectiveness of anti-PD-1/PD-L1 treatment is still limited to a specific group of patients. An important advancement in cancer immunotherapy involves improving the PD-L1 protein degradation. This review thoroughly examined the processes by which PD-L1 breaks down, including the intracellular pathways of ubiquitination-proteasome and autophagy-lysosome. In addition, the analysis revealed changes that affect PD-L1 stability, such as phosphorylation and glycosylation. The significant consequences of these procedures on cancer immunotherapy and their potential role in innovative therapeutic approaches are emphasised. Our future efforts will focus on understanding new ways in which PD-L1 degradation is controlled and developing innovative treatments, such as proteolysis-targeting chimeras designed specifically to degrade PD-L1. It is crucial to have a thorough comprehension of these pathways in order to improve cancer immunotherapy strategies and hopefully improve therapeutic effectiveness.

Clinically relevant stratification of lung squamous carcinoma patients based on ubiquitinated proteasome genes for 3P medical approach

Relevance

The proteasome is a crucial mechanism that regulates protein fate and eliminates misfolded proteins, playing a significant role in cellular processes. In the context of lung cancer, the proteasome's regulatory function is closely associated with the disease's pathophysiology, revealing multiple connections within the cell. Therefore, studying proteasome inhibitors as a means to identify potential pathways in carcinogenesis and metastatic progression is crucial in in-depth insight into its molecular mechanism and discovery of new therapeutic target to improve its therapy, and establishing effective biomarkers for patient stratification, predictive diagnosis, prognostic assessment, and personalized treatment for lung squamous carcinoma in the framework of predictive, preventive, and personalized medicine (PPPM; 3P medicine).

Methods

This study identified differentially expressed proteasome genes (DEPGs) in lung squamous carcinoma (LUSC) and developed a gene signature validated through Kaplan-Meier analysis and ROC curves. The study used WGCNA analysis to identify proteasome co-expression gene modules and their interactions with the immune system. NMF analysis delineated distinct LUSC subtypes based on proteasome gene expression patterns, while ssGSEA analysis quantified immune gene-set abundance and classified immune subtypes within LUSC samples. Furthermore, the study examined correlations between clinicopathological attributes, immune checkpoints, immune scores, immune cell composition, and mutation status across different risk score groups, NMF clusters, and immunity clusters.

Results

This study utilized DEPGs to develop an eleven-proteasome gene-signature prognostic model for LUSC, which divided samples into high-risk and low-risk groups with significant overall survival differences. NMF analysis identified six distinct LUSC clusters associated with overall survival. Additionally, ssGSEA analysis classified LUSC samples into four immune subtypes based on the abundance of immune cell infiltration with clinical relevance. A total of 145 DEGs were identified between high-risk and low-risk score groups, which had significant biological effects. Moreover, PSMD11 was found to promote LUSC progression by depending on the ubiquitin-proteasome system for degradation.

Conclusions

Ubiquitinated proteasome genes were effective in developing a prognostic model for LUSC patients. The study emphasized the critical role of proteasomes in LUSC processes, such as drug sensitivity, immune microenvironment, and mutation status. These data will contribute to the clinically relevant stratification of LUSC patients for personalized 3P medical approach. Further, we also recommend the application of the ubiquitinated proteasome system in multi-level diagnostics including multi-omics, liquid biopsy, prediction and targeted prevention of chronic inflammation and metastatic disease, and mitochondrial health-related biomarkers, for LUSC 3PM practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00352-w.

Identification and characterization of colorectal-cancer-associated SNPs on the SMAD7 locus

PURPOSE

Genome-wide association studies have identified SMAD7 as a colorectal cancer (CRC) susceptibility gene. However, its underlying mechanism has not yet been characterized. This study screened functional SNPs (fSNPs) related to colorectal cancer through Reel-seq and obtained regulatory proteins on functional SNPs.

METHODS

The candidate fSNPs on the SMAD7 locus were screened by Reel-seq method. Eight SNPs such as rs8085824 were identified as functional SNPs by luciferase reporter assay and EMSA, SDCP-MS and AIDP-WB revealed that HNRNPK can specifically bind to the rs8085824-C allele. The knockdown of HNRNPK by RNAi proved that HNRNPK could affect cell function by regulating SMAD7.

RESULTS

Eight functional SNPs was found on the SMAD7 locus in linkage disequilibrium (LD) with R2 > 0.8, i.e., rs12953717, rs7227023, rs34007497, rs58920878, rs8085824, rs4991143, rs4939826, and rs7227023. We also identified allele-imbalanced binding of HNRNPK to rs8085824, H1-3 to rs12953717, THOC6 to rs7227023, and DDX21 to rs58920878. Further functional analysis revealed that these proteins are the regulatory proteins that modulate the expression of SMAD7 in the human colorectal cancer cell line DLD1. In particular, we discovered that siRNA knockdown of HNRNPK inhibits cell proliferation and cell clonal formation by downregulating SMAD7, as the decreased cell proliferation and cell clonal formation in the siRNA HNRNPK knockdown cells was restored by SMAD7 overexpression.

CONCLUSION

Our findings reveal a mechanism which underlies the contribution of the fSNP rs8085824 on the SMD7 locus to CRC susceptibility.

Exosomal microRNA/miRNA Dysregulation in Respiratory Diseases: From Mycoplasma-Induced Respiratory Disease to COVID-19 and Beyond

Respiratory diseases represent a significant economic and health burden worldwide, affecting millions of individuals each year in both human and animal populations. MicroRNAs (miRNAs) play crucial roles in gene expression regulation and are involved in various physiological and pathological processes. Exosomal miRNAs and cellular miRNAs have been identified as key regulators of several immune respiratory diseases, such as chronic respiratory diseases (CRD) caused by Mycoplasma gallisepticum (MG), Mycoplasma pneumoniae pneumonia (MMP) caused by the bacterium Mycoplasma pneumoniae, coronavirus disease 2019 (COVID-19), chronic obstructive pulmonary disease (COPD), asthma, and acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Consequently, miRNAs seem to have the potential to serve as diagnostic biomarkers and therapeutic targets in respiratory diseases. In this review, we summarize the current understanding of the functional roles of miRNAs in the above several respiratory diseases and discuss the potential use of miRNAs as stable diagnostic biomarkers and therapeutic targets for several immune respiratory diseases, focusing on the identification of differentially expressed miRNAs and their targeting of various signaling pathways implicated in disease pathogenesis. Despite the progress made, unanswered questions and future research directions are discussed to facilitate personalized and targeted therapies for patients with these debilitating conditions.

SMAD Proteins in TGF-β Signalling Pathway in Cancer: Regulatory Mechanisms and Clinical Applications

Suppressor of mother against decapentaplegic (SMAD) family proteins are central to one of the most versatile cytokine signalling pathways in metazoan biology, the transforming growth factor-β (TGF-β) pathway. The TGF-β pathway is widely known for its dual role in cancer progression as both an inhibitor of tumour cell growth and an inducer of tumour metastasis. This is mainly mediated through SMAD proteins and their cofactors or regulators. SMAD proteins act as transcription factors, regulating the transcription of a wide range of genes, and their rich post-translational modifications are influenced by a variety of regulators and cofactors. The complex role, mechanisms, and important functions of SMAD proteins in tumours are the hot topics in current oncology research. In this paper, we summarize the recent progress on the effects and mechanisms of SMAD proteins on tumour development, diagnosis, treatment and prognosis, and provide clues for subsequent research on SMAD proteins in tumours.

PHF14 enhances DNA methylation of SMAD7 gene to promote TGF-β-driven lung adenocarcinoma metastasis

Aberrant activation of TGF-β signaling plays a pivotal role in cancer metastasis and progression. However, molecular mechanisms underlying the dysregulation of TGF-β pathway remain to be understood. Here, we found that SMAD7, a direct downstream transcriptional target and also a key antagonist of TGF-β signaling, is transcriptionally suppressed in lung adenocarcinoma (LAD) due to DNA hypermethylation. We further identified that PHF14 binds DNMT3B and serves as a DNA CpG motif reader, recruiting DNMT3B to the SMAD7 gene locus, resulting in DNA methylation and transcriptional suppression of SMAD7. Our in vitro and in vivo experiments showed that PHF14 promotes metastasis through binding DNMT3B to suppress SMAD7 expression. Moreover, our data revealed that PHF14 expression correlates with lowered SMAD7 level and shorter survival of LAD patients, and importantly that SMAD7 methylation level of circulating tumor DNA (ctDNA) can potentially be used for prognosis prediction. Together, our present study illustrates a new epigenetic mechanism, mediated by PHF14 and DNMT3B, in the regulation of SMAD7 transcription and TGF-β-driven LAD metastasis, and suggests potential opportunities for LAD prognosis.

TGF-β as Predictive Marker and Pharmacological Target in Lung Cancer Approach

Lung cancer (LC) represents the leading cause of cancer incidence and mortality worldwide. LC onset is strongly related to genetic mutations and environmental interactions, such as tobacco smoking, or pathological conditions, such as chronic inflammation. Despite advancement in knowledge of the molecular mechanisms involved in LC, this tumor is still characterized by an unfavorable prognosis, and the current therapeutic options are unsatisfactory. TGF-β is a cytokine that regulates different biological processes, particularly at the pulmonary level, and its alteration has been demonstrated to be associated with LC progression. Moreover, TGF-β is involved in promoting invasiveness and metastasis, via epithelial to mesenchymal transition (EMT) induction, where TGF-β is the major driver. Thus, a TGF-β-EMT signature may be considered a potential predictive marker in LC prognosis, and TGF-β-EMT inhibition has been demonstrated to prevent metastasis in various animal models. Concerning a LC therapeutic approach, some TGF-β and TGF-β-EMT inhibitors could be used in combination with chemo- and immunotherapy without major side effects, thereby improving cancer therapy. Overall, targeting TGF-β may be a valid possibility to fight LC, both in improving LC prognosis and cancer therapy, via a novel approach that could open up new effective strategies against this aggressive cancer.

Role of mitochondrial stress and the NLRP3 inflammasome in lung diseases

BACKGROUND

As an organelle essential for intracellular energy supply, mitochondria are involved in intracellular metabolism and inflammation, and cell death. The interaction of mitochondria with the NLRP3 inflammasome in the development of lung diseases has been extensively studied. However, the exact mechanism by which mitochondria mediate the activation of the NLRP3 inflammasome and trigger lung disease is still unclear.

METHODS

The literatures related to mitochondrial stress, NLRP3 inflammasome and lung diseases were searched in PubMed.

RESULTS

This review aims to provide new insights into the recently discovered mitochondrial regulation of the NLRP3 inflammasome in lung diseases. It also describes the crucial roles of mitochondrial autophagy, long noncoding RNA, micro RNA, altered mitochondrial membrane potential, cell membrane receptors, and ion channels in mitochondrial stress and regulation of the NLRP3 inflammasome, in addition to the reduction of mitochondrial stress by nuclear factor erythroid 2-related factor 2 (Nrf2). The effective components of potential drugs for the treatment of lung diseases under this mechanism are also summarized.

CONCLUSION

This review provides a resource for the discovery of new therapeutic mechanisms and suggests ideas for the development of new therapeutic drugs, thus promoting the rapid treatment of lung diseases.

Lung microRNAs Expression in Lung Cancer and COPD: A Preliminary Study

Non-small cell lung cancer (NSCLC) is one of the deadliest diseases worldwide and represents an impending burden on the healthcare system. Despite increasing attention, the mechanisms underlying tumorigenesis in cancer-related diseases such as COPD remain unclear, making novel biomarkers necessary to improve lung cancer early diagnosis. MicroRNAs (miRNAs) are short non-coding RNA that interfere with several pathways and can act as oncogenes or tumor suppressors. This study aimed to compare miRNA lung expression between subjects with NSCLC and COPD and healthy controls to obtain the miRNA expression profile by analyzing shared pathways. Lung specimens were collected from a prospective cohort of 21 sex-matched subjects to determine the tissue miRNA expression of hsa-miR-34a-5p, 33a-5p, 149-3p, 197-3p, 199-5p, and 320a-3p by RT-PCR. In addition, an in silico prediction of miRNA target genes linked to cancer was performed. We found a specific trend for has-miR-149-3p, 197-3p, and 34a-5p in NSCLC, suggesting their possible role as an index of the tumor microenvironment. Moreover, we identified novel miRNA targets, such as the Cyclin-Dependent Kinase (CDK) family, linked to carcinogenesis by in silico analysis. In conclusion. this study identified lung miRNA signatures related to the tumorigenic microenvironment, suggesting their possible role in improving the evaluation of lung cancer onset.

Guggulsterone inhibits migration and invasion through proteasomal and lysosomal degradation in human glioblastoma cells

Glioblastoma multiforme (GBM) is a deadly brain malignancy, and current therapies offer limited survival benefit. The phytosterol guggulsterone (GS) has been shown to exhibit antitumor efficacy. This study aimed to investigate the effects of GS on migration and invasion and its underlying mechanisms in human GBM cell lines. After GS treatment, the survival rate of GBM cells was reduced, and the migration and invasion abilities of GBM cells were significantly decreased. There was also concomitant decreased expression of focal adhesion complex, matrix metalloproteinase-2 (MMP2), MMP9 and cathepsin B. Furthermore, GS induced ERK phosphorylation and autophagy, with increased p62 and LC3B-II expression. Notably, treatment of in GBM cells with the proteasome inhibitor MG132 or the lysosome inhibitor NH4Cl reversed the GS-mediated inhibition of migration and invasion. In an orthotopic xenograft mouse model, immunohistochemical staining of brain tumor tissues demonstrated that MMP2 and cathepsin B expression was reduced in GS-treated mice. GS treatment inhibited GBM cell migration and invasion via proteasomal and lysosomal degradation, suggesting its therapeutic potential in clinical use in the future.

Regulation of Life & Death by REGγ

REGγ, a proteasome activator belonging to the 11S (otherwise known as REG, PA28, or PSME) proteasome activator family, is widely present in many eukaryotes. By binding to the 20S catalytic core particle, REGγ acts as a molecular sieve to selectively target proteins for degradation in an ATP- and ubiquitin-independent manner. This non-canonical proteasome pathway directly regulates seemingly unrelated cellular processes including cell growth and proliferation, apoptosis, DNA damage response, immune response, and metabolism. By affecting different pathways, REGγ plays a vital role in the regulation of cellular life and death through the maintenance of protein homeostasis. As a promoter of cellular growth and a key regulator of several tumor suppressors, many recent studies have linked REGγ overexpression with tumor formation and suggested the REGγ-proteasome as a potential target of new cancer-drug development. This review will present an overview of the major functions of REGγ as it relates to the regulation of cellular life and death, along with new mechanistic insights into the regulation of REGγ.

Loss of deubiquitylase USP2 triggers development of glioblastoma via TGF-β signaling

Glioblastoma (GBM) is the most aggressive primary brain tumor as one of the deadliest cancers. The TGF-β signaling acts as an oncogenic factor in GBM, and plays vital roles in development of GBM. SMAD7 is a major inhibitor of TGF-β signaling, while the deubiquitination of SMAD7 has been poorly studied in GBM. Here, we found USP2 as a new prominent candidate that could regulate SMAD7 stability. USP2 was lost in GBM, leading to the poor prognosis in patients. Moreover, aberrant DNA methylation mediated by DNMT3A induced the low expression of USP2 in GBM. USP2 depletion induced TGF-β signaling and progression of GBM. In contrast, overexpressed USP2 suppressed TGF-β signaling and GBM development. Specifically, USP2 interacted with SMAD7 and prevented SMAD7 ubiquitination. USP2 directly cleaved Lys27- and Lys48-linked poly-ubiquitin chains of SMAD7, and Lys27-linked poly-ubiquitin chains of SMAD7 K185 mediated the recruitment of SMAD7 to HERC3, which regulated Lys63-linked poly-ubiquitination of SMAD7. Moreover, we demonstrated that the DNMT3A inhibitor SGI-1027 induced USP2, suppressed TGF-β signaling and GBM development. Thus, USP2 repressed development of GBM by inhibition TGF-β signaling pathway via the deubiquitination of SMAD7.

A Bibliometric Analysis Based on Web of Science: Current Perspectives and Potential Trends of SMAD7 in Oncology

Background: The number of publications on SMAD7 in the field of oncology is increasing rapidly with an upward tendency. In most cases, the mechanisms of carcinogenesis usually relate to disorders of signaling activity. Considering the crucial role of SMAD7 in the crosstalk of multiple signaling pathways, it is necessary to clarify and define the dominant research topics, core authors, and their cumulative research contributions, as well as the cooperative relationships among documents or researchers.

Methods: Altogether, 3477 documents were retrieved from the Web of Science Core Collection with the following criteria: TS= (SMAD7 OR SMAD7-protein OR Small-Mothers-Against-Decapentaplegic-7) refined by WEB OF SCIENCE CATEGORY (ONCOLOGY) AND [excluding] PUBLICATION YEARS (2021) AND DOCUMENT TYPES (ARTICLE OR REVIEW) AND LANGUAGES (ENGLISH) AND WEB OF SCIENCE INDEX (Web of Science Core Collection, SCI), and the timespan of 2011–2020. Bibliometric visualization analysis was conducted with CiteSpace and VOSviewer.

Results: The number of documents grew each year. A total of 2703 articles and 774 reviews were identified from 86 countries/regions, 3524 organizations, 928 journals, and 19,745 authors. China was the most prolific country, with 1881 documents. Contributions from China, the United States, and Germany were the most substantial. The most influential author was Lan Huiyao at The Chinese University of Hong Kong, with 24 publications and 2348 total citations. The bibliometric analysis showed that multilateral cooperation among diverse institutions or investigators was beneficial to high-quality outputs. The keyword “PPAR-gamma” exhibited the strongest burst in recent years, suggesting a potent research focus in the future.

Conclusion: Research on SMAD7 in oncology is continuously developing. Bibliometrics is an interesting tool to present the characteristics of publication years, main authors, and productive organizations in a visualized way. It is worth mentioning that a prospective focus might be the specific mechanism of the interaction of PPAR-gamma with SMAD7 in oncology. In all, bibliometric analysis provides an overview and identifies potential research trends for further studies in this academic field.

Common Pathogenetic Mechanisms Underlying Aging and Tumor and Means of Interventions

Recently, there has been an increase in the incidence of malignant tumors among the older population. Moreover, there is an association between aging and cancer. During the process of senescence, the human body suffers from a series of imbalances, which have been shown to further accelerate aging, trigger tumorigenesis, and facilitate cancer progression. Therefore, exploring the junctions of aging and cancer and searching for novel methods to restore the junctions is of great importance to intervene against aging-related cancers. In this review, we have identified the underlying pathogenetic mechanisms of aging-related cancers by comparing alterations in the human body caused by aging and the factors that trigger cancers. We found that the common mechanisms of aging and cancer include cellular senescence, alterations in proteostasis, microbiota disorders (decreased probiotics and increased pernicious bacteria), persistent chronic inflammation, extensive immunosenescence, inordinate energy metabolism, altered material metabolism, endocrine disorders, altered genetic expression, and epigenetic modification. Furthermore, we have proposed that aging and cancer have common means of intervention, including novel uses of common medicine (metformin, resveratrol, and rapamycin), dietary restriction, and artificial microbiota intervention or selectively replenishing scarce metabolites. In addition, we have summarized the research progress of each intervention and revealed their bidirectional effects on cancer progression to compare their reliability and feasibility. Therefore, the study findings provide vital information for advanced research studies on age-related cancers. However, there is a need for further optimization of the described methods and more suitable methods for complicated clinical practices. In conclusion, targeting aging may have potential therapeutic effects on aging-related cancers.

LASP1 Induces Epithelial-Mesenchymal Transition in Lung Cancer through the TGF-β1/Smad/Snail Pathway

Background. LIM and SH3 domain protein 1 (LASP1), highly expressed in a variety of tumors, is considered as a novel tumor metastasis biomarker. However, it is unknown which signaling pathway works and how the signal transduces into cell nucleus to drive tumor progression by LASP1. The aim of this study is to explore the essential role of LASP1 in TGF-β1-induced epithelial-mesenchymal transition (EMT) in lung cancer cells. Methods. The gene and protein levels of LASP-1 were successfully silenced or overexpressed by LASP-1 shRNA lentivirus or pcDNA in TGF-β1-treated lung cancer cell lines, respectively. Then, the cells were developed EMT by TGF-β1. The cell abilities of invasion, migration, and proliferation were measured using Transwell invasion assay, wound healing assay, and MTT assay, respectively. Western blotting was used to observe the protein levels of EMT-associated molecules, including N-cadherin, vimentin, and E-cadherin, and the key molecules in the TGF-β1/Smad/Snail signaling pathway, including pSmad2 and Smad2, pSmad3 and Smad3, and Smad7 in cell lysates, as well as Snail1, pSmad2, and pSmad3 in the nucleus. Results. TGF-β1 induced higher LASP1 expression. LASP1 silence and overexpression blunted or promoted cell invasion, migration, and proliferation upon TGF-β1 stimulation. LASP1 also regulated the expression of vimentin, N-cadherin, and E-cadherin in TGF-β1-treated cells. Activity of key Smad proteins (pSmad2 and pSmad3) and protein level of Smad7 were markedly regulated through LASP1. Furthermore, LASP1 affected the nuclear localizations of pSmad2, pSmad3, and Snail1. Conclusion. This study reveals that LASP1 regulates the TGF-β1/Smad/Snail signaling pathway and EMT markers and features, involving in key signal molecules and their nuclear levels. Therefore, LASP1 might be a drug target in lung cancer.

Construction of a Ferroptosis-Related Long Non-coding RNA Prognostic Signature and Competing Endogenous RNA Network in Lung Adenocarcinoma

Ferroptosis-related genes play an important role in the progression of lung adenocarcinoma (LUAD). However, the potential function of ferroptosis-related lncRNAs in LUAD has not been fully elucidated. Thus, to explore the potential role of ferroptosis-related lncRNAs in LUAD, the transcriptome RNA-seq data and corresponding clinical data of LUAD were downloaded from the TCGA dataset. Pearson correlation was used to mine ferroptosis-related lncRNAs. Differential expression and univariate Cox analysis were performed to screen prognosis related lncRNAs. A ferroptosis-related lncRNA prognostic signature (FLPS), which included six ferroptosis-related lncRNAs, was constructed by the least absolute shrinkage and selection operator (LASSO) Cox regression. Patients were divided into a high risk-score group and low risk-score group by the median risk score. Receiver operating characteristic (ROC) curves, principal component analysis (PCA), and univariate and multivariate Cox regression were performed to confirm the validity of FLPS. Enrichment analysis showed that the biological processes, pathways and markers associated with malignant tumors were more common in high-risk subgroups. There were significant differences in immune microenvironment and immune cells between high- and low-risk groups. Then, a nomogram was constructed. We further investigated the relationship between six ferroptosis-related lncRNAs and tumor microenvironment and tumor stemness. A competing endogenous RNA (ceRNA) network was established based on the six ferroptosis-related lncRNAs. Finally, we detected the expression levels of ferroptosis-related lncRNAs in clinical samples through quantitative real-time polymerase chain reaction assay (qRT-PCR). In conclusion, we identified the prognostic ferroptosis-related lncRNAs in LUAD and constructed a prognostic signature which provided a new strategy for the evaluation and prediction of prognosis in LUAD.

Identification of a TGF-β/SMAD/lnc-UTGF positive feedback loop and its role in hepatoma metastasis

Aberrant activation of the TGF-β/SMAD signaling pathway is often observed in hepatocellular carcinoma (HCC). Whether lncRNA regulates the TGF-β/SMAD signaling remains largely unknown. Here, we identified an oncogenic lncRNA that was upregulated in HCC and was transcriptionally induced by TGF-β (named lnc-UTGF, lncRNA upregulated by TGF-β). Upon TGF-β stimulation, SMAD2/3 bound to the lnc-UTGF promoter and activated lnc-UTGF expression. In turn, the TGF-β/SMAD signaling was augmented by overexpressing lnc-UTGF, but was inhibited by silencing lnc-UTGF. Mechanism investigations revealed that lnc-UTGF interacted with the mRNAs of SMAD2 and SMAD4 via complementary base-pairing, resulting in enhanced stability of SMAD2/4 mRNAs. These data suggest a novel TGF-β/SMAD/lnc-UTGF positive feedback circuitry. Subsequent gain- and loss-of-function analyses disclosed that lnc-UTGF promoted the migration and invasion of hepatoma cells, and this effect of lnc-UTGF was attenuated by repressing SMAD2/4 expression or by mutating the SMAD2/4-binding sites in lnc-UTGF. Studies using mouse models further confirmed that in vivo metastasis of hepatoma xenografts was inhibited by silencing lnc-UTGF, but was enhanced by ectopic expression of lnc-UTGF. The lnc-UTGF level was positively correlated with the SMAD2/4 levels in xenografts. Consistently, we detected an association of lnc-UTGF upregulation with increase of SMAD2, SMAD4, and their metastasis effector SNAIL1 in human HCC. And high lnc-UTGF level was also significantly associated with enhanced metastasis potential, advanced TNM stages, and worse recurrence-free survival. Conclusion: there exists a lnc-UTGF-mediated positive feedback loop of the TGF-β signaling and its deregulation promotes hepatoma metastasis. These findings may provide a new therapeutic target for HCC metastasis.

CTI-2 Inhibits Metastasis and Epithelial-Mesenchymal Transition of Breast Cancer Cells by Modulating MAPK Signaling Pathway

Although some breast cancer patients die due to tumor metastasis rather than from the primary tumor, the molecular mechanism of metastasis remains unclear. Therefore, it is necessary to inhibit breast cancer metastasis during cancer treatment. In this case, after designing and synthesizing CTI-2, we found that CTI-2 treatment significantly reduced breast cancer cell metastasis in vivo and in vitro. Notably, with the treatment of CTI-2 in breast cancer cells, the expression level of E-cadherin increased, while the expression level of N-cadherin and vimentin decreased. In addition, after CTI-2 treatment, those outflow levels for p-ERK, p-p38, and p-JNK diminished, while no significant changes in the expression levels of ERK, JNK, or p38 were observed. Our conclusion suggested that CTI-2 inhibits the epithelial-mesenchymal transition (EMT) of breast carcinoma cells by inhibiting the activation of the mitogen-activated protein kinase (MAPK) signaling pathway, thereby inhibiting the metastasis of breast tumor cells. Therefore, we believe that CTI-2 is another candidate for breast tumor medication.

3'untranslated regions (3'UTR) of Gelsolin mRNA displays anticancer effects in non-small cell lung cancer (NSCLC) cells

RNA-based therapeutics has attracted substantial interest from both academics and pharmaceutical companies. In this study, we investigated the function and the underlying mechanism of Gelsolin (GSN) 3'UTR in NSCLC H1299 and A549 cells. We found that transfected Flag-GSN plasmids significantly increased the proliferation, migration and invasion of NSCLC cells, whereas GSN 3'UTR could suppress the promotional effect of GSN protein on the development of NSCLC in vitro. Interestingly, we observed that these in vitro anticancer effects of GSN 3'UTR was independent of the co-expression with GSN coding sequence. Moreover, transfected GSN 3'UTR affected the actin-cytoskeleton remodeling and epithelial-mesenchymal transition (EMT) processes in H1299 and A549 cells, and targeted the co-expressed proteins to the plasma membrane. Subsequently, RNA pull-down assays have been performed to identify Tra2β protein as a GSN 3'UTR binder. We then showed that Tra2β was important for the localized protein expression mediated by GSN 3'UTR. Taken together, our results suggested that GSN 3'UTR may exert anticancer functions in NSCLC cells through regulating the subcellular localized expression of GSN protein mediated by the interaction between GSN 3'UTR-Tra2β.

MiR-21-3p Promotes Hepatocellular Carcinoma Progression via SMAD7/YAP1 Regulation

Background

Hepatocellular carcinoma (HCC) remains a major global health burden due to its high prevalence and mortality. Emerging evidence reveals that microRNA (miRNA) plays a vital role in cancer pathogenesis and is widely involved in the regulation of signaling pathways via their targeting of downstream genes. MiR-21-3p, a liver-enriched miRNA, and SMAD7, the negative regulator of the TGF-β signaling pathway, likely exert a vital influence on HCC progression.

Aims

Here, we explore the role of the miR-21-3p-SMAD7/YAP1 axis on HCC pathogenesis.

Methods

MiRNA microarray analysis was performed for miRNA screening. The dual-luciferase assay was adopted for target verification. Expression of miRNA and related genes were quantified via qRT-PCR, western blotting, and immunohistochemical staining. Flow cytometry and the transwell migration assay were used to detail cell apoptosis, invasion and metastases. Rat models were established to explore the role of the miR-21-3p-SMAD7/YAP1 axis in hepatocarcinogenesis. Bioinformatics analysis was conducted for exploring genes of clinical significance.

Results

MiR-21-3p levels were found to be significantly elevated in hepatocellular carcinoma and indicate poor overall survival. High miR-21-3p levels were associated with advanced tumor stages (P = 0.029), in particular T staging (P = 0.026). Low SMAD7/high YAP1 levels were confirmed in both HCC and rat models with advanced liver fibrosis and cirrhosis. Besides, SMAD7 was demonstrated to be the direct target of miR-21-3p. The effect of MiR-21-3p on tumor phenotypes and YAP1 upregulation could be partly reversed via the restoration of SMAD7 expression in HCC cell lines. Overexpression of YAP1 after miR-21-3p upregulation promoted expression of nuclear transcription effector connective tissue growth factor. Co-survival analysis indicated that lower miR-21-3p/higher SMAD7 (P = 0.0494) and lower miR-21-3p/lower YAP1 (P = 0.0379) group patients had better overall survival rates. Gene Set Variation Analysis revealed that gene sets related to miR-21-3p and SMAD7 were significantly associated with the TGF-β signaling pathway in HCC.

Conclusion

MiR-21-3p promotes migration and invasion of HCC cells and upregulation of YAP1 expression via direct inhibition of SMAD7, underscoring a major epigenetic mechanism in the pathogenesis of HCC.

PA28γ: New Insights on an Ancient Proteasome Activator

PA28 (also known as 11S, REG or PSME) is a family of proteasome regulators whose members are widely present in many of the eukaryotic supergroups. In jawed vertebrates they are represented by three paralogs, PA28α, PA28β, and PA28γ, which assemble as heptameric hetero (PA28αβ) or homo (PA28γ) rings on one or both extremities of the 20S proteasome cylindrical structure. While they share high sequence and structural similarities, the three isoforms significantly differ in terms of their biochemical and biological properties. In fact, PA28α and PA28β seem to have appeared more recently and to have evolved very rapidly to perform new functions that are specifically aimed at optimizing the process of MHC class I antigen presentation. In line with this, PA28αβ favors release of peptide products by proteasomes and is particularly suited to support adaptive immune responses without, however, affecting hydrolysis rates of protein substrates. On the contrary, PA28γ seems to be a slow-evolving gene that is most similar to the common ancestor of the PA28 activators family, and very likely retains its original functions. Notably, PA28γ has a prevalent nuclear localization and is involved in the regulation of several essential cellular processes including cell growth and proliferation, apoptosis, chromatin structure and organization, and response to DNA damage. In striking contrast with the activity of PA28αβ, most of these diverse biological functions of PA28γ seem to depend on its ability to markedly enhance degradation rates of regulatory protein by 20S proteasome. The present review will focus on the molecular mechanisms and biochemical properties of PA28γ, which are likely to account for its various and complex biological functions and highlight the common features with the PA28αβ paralog.

Steps in metastasis: an updated review

Metastasis is the most complex and deadly event. Tumor-stromal interface is a place where invasion of tumor cells in the form of single-cell or collective migration occurs, with the latter being less common but more efficient. Initiation of metastasis relies on the tumor cell cross-talking with stromal cells and taking an epithelial-mesenchymal transition (EMT) in single cells, and a hybrid EMT in collective migratory cells. Stromal cross-talking along with an abnormal leaky vasculature facilitate intravasation of tumor cells, here the cells are called circulating tumor cells (CTCs). Tumor cells isolated from the primary tumor exploit several mechanisms to maintain their survival including rewiring metabolic demands to use sources available within the new environments, avoiding anoikis cell death when cells are detached from extracellular matrix (ECM), adopting flow mechanic by acquiring platelet shielding and immunosuppression by negating the activity of suppressor immune cells, such as natural killer (NK) cells. CTCs will adhere to the interstituim of the secondary organ/s, within which the newly arrived disseminative tumor cells (DTCs) undergo either dormancy or proliferation. Metastatic outgrowth is under the influence of several factors, such as the activity of macrophages, impaired autophagy and secondary site inflammatory events. Metastasis can be targeted by multiple ways, such as repressing the promoters of pre-metastatic niche (PMN) formation, suppressing environmental contributors, such as hypoxia, oxidative and metabolic stressors, and targeting signaling and cell types that take major contribution to the whole process. These strategies can be used in adjuvant with other therapeutics, such as immunotherapy.

Downregulation of lncRNA FGF12-AS2 suppresses the tumorigenesis of NSCLC via sponging miR-188-3p

Background

Non-small-cell lung carcinoma (NSCLC) seriously threatens the health of human beings. Aberrant expression of lncRNAs has been confirmed to be related with the progression of multiple malignant tumors, including NSCLC. LncRNA FGF12-AS2 has been considered to be upregulated in NSCLC. However, the mechanism by which FGF12-AS2 promotes the tumorigenesis of NSCLC remains elusive.

Methods

Gene and protein expressions in NSCLC cells were measured by q-PCR and western blot, respectively. CCK-8 and immunofluorescence staining were performed to detect the cell proliferation. Cell apoptosis was tested by flow cytometry. Transwell assay was used to detect the cell migration and invasion. Finally, the dual luciferase report assay was used to verify the relation among FGF12-AS2, miR-188-3p, and NCAPG2.

Results

Downregulation of FGF12-AS2 significantly inhibited the proliferation of NSCLC cells via inducing apoptosis. In addition, FGF12-AS2 silencing notably suppressed the migration and invasion of A549 cells. Meanwhile, FGF12-AS2 modulated the progression of NSCLC via regulation of miR-188-3p/NCAPG2 axis. Finally, knockdown of FGF12-AS2 inhibited the tumorigenesis of NSCLC via suppressing the EMT process of NSCLC.

Conclusion

Downregulation of lncRNA FGF12-AS2 suppressed the tumorigenesis of NSCLC via sponging miR-188-3p. Thus, FGF12-AS2 may serve as a potential target for the treatment of NSCLC.

LncRNA DGCR5 plays a tumor-suppressive role in glioma via the miR-21/Smad7 and miR-23a/PTEN axes

Glioma is one of the most commonly diagnosed brain malignancies with a high cancer-related death rate in humans. The prognosis of glioma patients is still unsatisfactory. In the present study, we attempted to identify lncRNAs and miRNAs that might be related to NF-κB-mediated epithelial-mesenchymal transition in glioma cells based on online microarray expression profiles, and investigate the specific effects of lncRNA-miRNA-mRNA axes on glioma cell phenotypes. Herein, we identified lncRNA DGCR5 as a downregulated lncRNA in glioma that was negatively regulated by NF-κB1 in an NF-κB1 RE-dependent manner. LncRNA DGCR5 overexpression significantly inhibited the capacity of glioma cells to proliferate, migrate, and invade, whereas promoted the apoptosis of glioma cells. Moreover, lncRNA DGCR5 overexpression upregulated the epithelial marker E-cadherin while downregulating the mesenchymal marker VIM, as well as Snai2 and TWIST. Regarding the underlying molecular mechanisms, lncRNA DGCR5 could inhibit miR-21 and miR-23a expression, and miR-21 or miR-23a overexpression significantly reversed the tumor-suppressive effects of lncRNA DGCR5 overexpression. LncRNA DGCR5 exerted its tumor-suppressive effects through the DGCR5/miR-21/Smad7 and DGCR5/miR-23a/PTEN axes. In conclusion, lncRNA DGCR5 suppresses the capacity of glioma cells to migrate and invade via miR-21/Smad7, whereas it inhibits the proliferation and enhances the apoptosis of glioma cells through miR-23a/PTEN.

Current perspectives on inhibitory SMAD7 in health and disease

Transforming growth factor β (TGF-β) family members play an extensive role in cellular communication that orchestrates both early development and adult tissue homeostasis. Aberrant TGF-β family signaling is associated with a pathological outcome in numerous diseases, and in-depth understanding of molecular and cellular processes could result in therapeutic benefit for patients. Canonical TGF-β signaling is mediated by receptor-regulated SMADs (R-SMADs), a single co-mediator SMAD (Co-SMAD), and inhibitory SMADs (I-SMADs). SMAD7, one of the I-SMADs, is an essential negative regulator of the pleiotropic TGF-β and bone morphogenetic protein (BMP) signaling pathways. In a negative feedback loop, SMAD7 inhibits TGF-β signaling by providing competition for TGF-β type-1 receptor (TβRI), blocking phosphorylation and activation of SMAD2. Moreover, SMAD7 recruits E3 ubiquitin SMURF ligases to the type I receptor to promote ubiquitin-mediated proteasomal degradation. In addition to its role in TGF-β and BMP signaling, SMAD7 is regulated by and implicated in a variety of other signaling pathways and functions as a mediator of crosstalk. This review is focused on SMAD7, its function in TGF-β and BMP signaling, and its role as a downstream integrator and crosstalk mediator. This crucial signaling molecule is tightly regulated by various mechanisms. We provide an overview of the ways by which SMAD7 is regulated, including noncoding RNAs (ncRNAs) and post-translational modifications (PTMs). Finally, we discuss its role in diseases, such as cancer, fibrosis, and inflammatory bowel disease (IBD).

Downregulation of miR-7-5p Inhibits the Tumorigenesis of Esophagus Cancer via Targeting KLF4

Background

Esophageal cancer (EC) is one of the aggressive gastrointestinal malignancies. It has been reported that microRNAs (miRNAs) play key roles during the tumorigenesis of EC. To identify novel potential targets for EC, differential expressed miRNAs (DEG) between EC and adjacent normal tissues were analyzed with bioinformatics tool.

Methods

The differential expression of miRNAs between EC and adjacent normal tissues was analyzed. CCK-8 and Ki67 staining were used to detect the cell proliferation. Flow cytometry was performed to test the cell apoptosis. The correlation between miR-7-5p and KLF4 was detected by dual-luciferase report assay. Gene and protein expression in EC cells or in tissues were measured by qRT-PCR and Western blot, respectively. Cell migration and invasion were detected with transwell assay. Xenograft mice model was established to investigate the role of miR-7-5p in EC tumorigenesis in vivo.

Results

MiR-7-5p was found to be negatively correlated with the survival rate of patient with EC. In addition, downregulation of miR-7-5p significantly inhibited the growth and invasion of EC cells. Meanwhile, miR-7-5p directly targeted KLF4 in EC cells. Moreover, downregulation of miR-7-5p inhibited the tumorigenesis of EC via inactivating MAPK signaling pathway in vivo.

Conclusion

Downregulation of miR-7-5p notably suppressed the progression of EC via targeting KLF4. Thus, miR-7-5p might serve as a new target for the treatment of EC.

MiR-581/SMAD7 Axis Contributes to Colorectal Cancer Metastasis: A Bioinformatic and Experimental Validation-Based Study

Metastasis is a well-known poor prognostic factor and primary cause of mortality in patients with colorectal cancer (CRC). Recently, with the progress of high through-put sequencing, aberrantly expressed non-coding RNAs (ncRNAs) were found to participate in the initiation and development of cancer. However, the mechanisms of ncRNA-mediated regulation of metastasis in CRC remain largely unknown. In this study, we systematically analyzed the expression network of microRNAs (miRNAs) and genes in CRC metastasis using bioinformatics, and discovered that the miR-581/SMAD7 axis could be a potential factor that drives CRC metastasis. A dual luciferase report assay and protein analysis confirmed the binding relationship between miR-581 and SMAD7. Further functional assays revealed that miR-581 inhibition could suppress cell proliferation and induce apoptosis in SW480 cells. Up-regulation or down-regulation of miR-581 could both affect cell invasion capacity and modulate epithelial to mesenchymal transition (EMT) via a SMAD7/TGFβ signaling pathway. In conclusion, our findings elucidated that miR-581/SMAD7 could be essential for CRC metastasis, and may serve as a potential therapeutic target for CRC patients.

Role of oncogenic REGγ in cancer

Cancer is a critical global health-care problem with limited therapeutic options. Since cancers are life-threatening illnesses, the identification of a promising oncotarget and its clinical correlates are relevant. Mounting evidence has emerged indicating that REG gamma (REGγ), a member of the 11S proteasome activators, plays a pivotal role in the development of multiple human cancers. However, an elaborate summary on the association between REGγ and cancer is still lacking. In this Review, we discuss how REGγ, through its ATP- and ubiquitin-independent manners, represents a promising cancer biomarker and therapeutic oncotarget for multiple human cancers. Aberrant REGγ expression closely associated with tumorigenesis attributes to its biological functions for controlling and regulating cell cycle, proliferation, migration, invasion, angiogenesis, and metastasis of the cancer cells by degrading proteins of cytosol and nucleus in the eukaryotic cells. REGγ serves as a molecular switch to activate multifarious oncogenic signaling pathways, such as MAPK/p38, TGF-β/Smad, and Wnt/β-catenin. The review describes that targeting REGγ may provide new diagnostic and therapeutic applications in cancer.

Hsa_circ_0018818 knockdown suppresses tumorigenesis in non-small cell lung cancer by sponging miR-767-3p

To identify potential therapeutic targets in non-small cell lung cancer NSCLC, we conducted a bioinformatics analysis of circRNAs differentially expressed between NSCLC tissues and adjacent normal tissues. Cell proliferation and apoptosis was assessed using CCK-8 and flow cytometry, respectively. A connection between hsa_circ_0018818 and miR-767-3p was confirmed in dual luciferase reporter assays. Gene and protein expression in NSCLC cells were measured using quantitative PCR and Western-blotting, respectively. And a xenograft tumor model was established to assess the function of hsa_circ_0018818 in NSCLC in vivo. Hsa_circ_0018818 was greatly upregulated in NSCLC tumor tissues. Knocking down hsa_circ_0018818 using a targeted shRNA inhibited the proliferation and invasiveness of NSCLC cells and induced their apoptosis via the miR-767-3p/Nidogen 1 (NID1) signaling axis. Hsa_circ_0018818 knockdown also inactivated Epithelial-mesenchymal transition (EMT) process and PI3K/Akt signaling. In summary, hsa_circ_0018818 knockdown inhibited NSCLC tumorigenesis in vitro and in vivo, which suggests it could potentially serve as a target for the treatment of NSCLC.

MiR-503-5p functions as an oncogene in oral squamous cell carcinoma by targeting Smad7

BACKGROND

Oral squamous cell carcinoma (OSCC) is a common oral malignancy. Previous studies indicated that the level of miR-503-5p was upregulated in OSCC tissues. However, the mechanism by which miR-503-5p regulates the proliferation and invasion of OSCC cells remains unclear. Therefore, this study aimed to investigate the role of miR-503-5p during the progression of OSCC.

METHODS

The level of miR-503-5p in Tca8113 cells was detected using RT-qPCR assay. In addition, CCK-8, transwell assays and flow cytometry assays were conducted to detect cell viability, migration, invasion and apoptosis, respectively. Meanwhile, the dual luciferase reporter assay was applied to explore the interaction between miR-503-5p and Smad7 in Tca8113 cells.

RESULTS

Overexpression of miR-503-5p significantly promoted the proliferation, migration and invasion of Tca8113 cells, while downregulation of miR-503-5p markedly inhibited proliferation, migration and invasion of cells. In addition, knockdown of miR-503-5p obviously induced the apoptosis of Tca8113 cells via increasing the levels of Bax and cleaved caspase 3, and decreased the expression of Bcl-2. Moreover, SMAD family member 7 (Smad7) was identified as a direct binding target of miR-503-5p in Tca8113 cells. Overexpression of miR-503-5p significantly downregulated the levels of Smad7 and E-cadherin, but upregulated the levels of N-cadherin and MMP-9 in Tca8113 cells.

CONCLUSION

These results indicated that miR-503-5p might act as an oncogene in OSCC cells by targeting Smad7. Therefore, miR-503-5p might act as a novel and potential therapeutic target for the treatment of OSCC.