Stabilization of MORC2 by estrogen and antiestrogens through GPER1- PRKACA-CMA pathway contributes to estrogen-induced proliferation and endocrine resistance of breast cancer cells

Accurate network pharmacology and novel ingredients formula of herbal targeting estrogen signaling for psoriasis intervention

ETHNOPHARMACOLOGICAL RELEVANCE

As a common chronic inflammatory skin disease, psoriasis is incompletely understood and brings a lot of distress to patients. The estrogen signaling pathway has been implicated in its pathogenesis, making it a potential therapeutic target. Si Cao Formula (SCF) has demonstrated promise in treating psoriasis clinically. However, its molecular mechanisms concerning psoriasis remain largely unexplored.

AIM OF THE STUDY

To elucidate the underlying mechanisms of the action of SCF on psoriasis.

MATERIALS AND METHODS

Active ingredients were identified by LC-MS/MS. After the treatment with SCF, the exploration of differentially expressed proteins (DEPs) were conducted using tandem mass tag (TMT)-based quantitative proteomics analysis. By GO/KEGG, WikiPathways and network pharmacology, core signaling pathway and protein targets were explored. Consequently, major signaling pathway and protein targets were validated by RT-qPCR, immunoblotting and immunofluorescence. Based on Lipinski's Rule of Five rules and molecular docking, 8 active compounds were identified that acted on the core targets.

RESULTS

41 compounds of SCF and 848 specific targets of these compounds were identified. There were 570 DEPs between IMQ (Imiquimod) and IMQ + SCF group, including 279 up-regulated and 304 down-regulated proteins. GO/KEGG, WikiPathways and network pharmacology revealed estrogen signaling pathway as the paramount pathways, through which SCF functioned on psoriasis. We further show novel ingredients formula of SCF contributes to estrogen signaling intervention, including liquiritin, parvisoflavone B, glycycoumarin, 8-prenylluteone, licochalcone A, licochalcone B, oxymatrine, and 13-Hydroxylupanine, where targeting MAP2K1, ILK, HDAC1 and PRKACA, respectively. Molecular docking proves that they have good binding properties.

CONCLUSION

Our results provide an in-depth view of psoriasis pathogenesis and herbal intervention, which expands our understanding of the systemic pharmacology to reveal the multiple ingredients and multiple targets of SCF and focus on one pathway (estrogen signaling pathway) may be a novel therapeutic strategy for psoriasis treatment of herbal medicine.

Blockade of a novel MAP4K4-LATS2-SASH1-YAP1 cascade inhibits tumorigenesis and metastasis in luminal breast cancer

Novel components in the noncanonical Hippo pathway that mediate the growth, metastasis, and drug resistance of breast cancer (BC) cells need to be identified. Here, we showed that expression of SAM and SH3 domain-containing protein 1 (SASH1) is negatively correlated with expression of mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) in a subpopulation of patients with luminal-subtype BC. Downregulated SASH1 and upregulated MAP4K4 synergistically regulated the proliferation, migration, and invasion of luminal-subtype BC cells. The expression of LATS2, SASH1, and YAP1 and the phosphorylation of YAP1 were negatively regulated by MAP4K4, and LATS2 then phosphorylated SASH1 to form a novel MAP4K4-LATS2-SASH1-YAP1 cascade. Dephosphorylation of Yes1 associated transcriptional regulator (YAP1), YAP1/TAZ nuclear translocation, and downstream transcriptional regulation of YAP1 were promoted by the combined effects of ectopic MAP4K4 expression and SASH1 silencing. Targeted inhibition of MAP4K4 blocked proliferation, cell migration, and ER signaling both in vitro and in vivo. Our findings reveal a novel MAP4K4-LATS2-SASH1-YAP1 phosphorylation cascade, a noncanonical Hippo pathway that mediates ER signaling, tumorigenesis, and metastasis in breast cancer. Targeted intervention with this noncanonical Hippo pathway may constitute a novel alternative therapeutic approach for endocrine-resistant BC.

Oncogenic MORC2 in cancer development and beyond

Microrchidia CW-type zinc finger 2 (MORC2) is a member of the MORC superfamily of nuclear proteins. Growing evidence has shown that MORC2 not only participates in gene transcription and chromatin remodeling but also plays a key in human disease and tumor development by regulating the expression of downstream oncogenes or tumor suppressors. The present review provides an updated overview of MORC2 in the aspect of cancer hallmark and therapeutic resistance and summarizes its upstream regulators and downstream target genes. This systematic review may provide a favorable theoretical basis for emerging players of MORC2 in tumor development and new insight into the potential clinical application of basic science discoveries in the future.

Heat shock protein family A member 8 serving as a co-activator of transcriptional factor ETV4 up-regulates PHLDA2 to promote the growth of liver cancer

Heat shock protein family A member 8 (HSPA8) participates in the folding or degradation of misfolded proteins under stress and plays critical roles in cancer. In this study, we investigated the function of HSPA8 in the development of liver cancer. By analyzing the TCGA transcriptome dataset, we found that HSPA8 was upregulated in 134 clinical liver cancer tissue samples, and positively correlated with poor prognosis. IHC staining showed the nuclear and cytoplasmic localization of HSPA8 in liver cancer cells. Knockdown of HSPA8 resulted in a decrease in the proliferation of HepG2 and Huh-7 cells. ChIP-seq and RNA-seq analysis revealed that HSPA8 bound to the promoter of pleckstrin homology-like domain family A member 2 (PHLDA2) and regulated its expression. The transcription factor ETV4 in HepG2 cells activated PHLDA2 transcription. HSPA8 and ETV4 could interact with each other in the cells and colocalize in the nucleus. From a functional perspective, we demonstrated that HSPA8 upregulated PHDLA2 through the coactivating transcription factor ETV4 to enhance the growth of liver cancer in vitro and in vivo. From a therapeutic perspective, we identified both HSPA8 and PHDLA2 as novel targets in the treatment of HCC. In conclusion, this study demonstrates that HSPA8 serves as a coactivator of ETV4 and upregulates PHLDA2, leading to the growth of HCC, and is a potential therapeutic target in HCC treatment.

Novel Insights into the Role of Chromatin Remodeler MORC2 in Cancer

A newly discovered chromatin remodeler, MORC2, is a Microrchidia (MORC) family member. MORC2 acts as a chromatin remodeler by binding to the DNA and changing chromatin conformation using its ATPase domain. MORC2 is highly expressed in a variety of human cancers. It controls diverse signaling pathways essential for cancer development through its target genes and interacting partners. MORC2 promotes cancer cells' growth, invasion, and migration by regulating the expression of genes involved in these processes. MORC2 is localized primarily in the nucleus and is also found in the cytoplasm. In the cytoplasm, MORC2 interacts with adenosine triphosphate (ATP)-citrate lyase (ACLY) to promote lipogenesis and cholesterogenesis in cancer. In the nucleus, MORC2 interacts with the transcription factor c-Myc to control the transcription of genes involved in glucose metabolism to drive cancer cell migration and invasion. Furthermore, MORC2 recruits on to the promoters of tumor suppressor genes to repress their transcription and expression to promote oncogenesis. In addition to its crucial function in oncogenesis, it plays a vital role in DNA repair. Overall, this review concisely summarizes the current knowledge about MORC2-regulated molecular pathways involved in cancer.

Alternative polyadenylation reprogramming of MORC2 induced by NUDT21 loss promotes KIRC carcinogenesis

Alternative polyadenylation (APA), a posttranscriptional mechanism of gene expression via determination of 3'UTR length, has an emerging role in carcinogenesis. Although abundant APA reprogramming is found in kidney renal clear cell carcinoma (KIRC), which is one of the major malignancies, whether APA functions in KIRC remains unknown. Herein, we found that chromatin modifier MORC2 gained oncogenic potential in KIRC among the genes with APA reprogramming, and moreover, its oncogenic potential was enhanced by 3'UTR shortening through stabilization of MORC2 mRNA. MORC2 was found to function in KIRC by downregulating tumor suppressor DAPK1 via DNA methylation. Mechanistically, MORC2 recruited DNMT3A to facilitate hypermethylation of the DAPK1 promoter, which was strengthened by 3'UTR shortening of MORC2. Furthermore, loss of APA regulator NUDT21, which was induced by DNMT3B-mediated promoter methylation, was identified as responsible for 3'UTR shortening of MORC2 in KIRC. Additionally, NUDT21 was confirmed to act as a tumor suppressor mainly depending on downregulation of MORC2. Finally, we designed an antisense oligonucleotide (ASO) to enhance NUDT21 expression and validated its antitumor effect in vivo and in vitro. This study uncovers the DNMT3B/NUDT21/APA/MORC2/DAPK1 regulatory axis in KIRC, disclosing the role of APA in KIRC and the crosstalk between DNA methylation and APA.

High expression of MORC2 predicts worse neoadjuvant chemotherapy efficacy in triple negative breast cancer

Tumor infiltrating lymphocytes (TILs) are closely related to the patients' prognosis. Recently, Microrchidia 2 (MORC2) has been documented as a prognostic and predictive biomarker in triple negative breast cancer (TNBC). To compare whether MORC2 is a better predictor than TILs, as well as clinicopathological parameters, in predicting the efficacy of neoadjuvant chemotherapy (NAC) in TNBC, we detected the expression of MORC2 on neoplastic cells through immunohistochemistry and quantified the stromal TILs through Hematoxylin-eosin staining on core biopsies from 50 locally advanced TNBC patients who underwent standard NAC. Among all the 50 patients, 28 (56%) cases had residual tumors, while the other 22 (44%) achieved pathologic complete response (pCR). In these studied patients, age and T-stage showed no correlation with pCR rate, while percentage of TILs, nodal involvement and expression of MORC2 on tumor cells showed significant association with pCR rate. Positive nodal involvement was correlation with worse pathologic response at multivariate analysis (P = .0036), and high TILs levels (≥50%) was positively associated with better NAC efficacy at univariate analysis (P = .002). Whereas high expression of MORC2 was statistically associated with worse pCR rate both at univariate (P < .001) and multivariate (P = .036) analysis. Our results indicate that MORC2 expression has a better predictive role in predicting the efficacy of NAC than TILs in TNBC patients.

Environmental estrogens shape disease susceptibility

Along with industrialization, the environment is flooded with endocrine-disrupting chemicals, among which substances with estrogenic effects have attracted widespread attention in medical research. In terms of molecular mechanism, environmental estrogens can cause endocrine and metabolic disorders; interfere with multiple carcinogenic pathways; and lead to neurobehavioral disorders, reproductive toxicity, and multi- or trans-generational phenotypic abnormalities. However, many of the results from molecular and animal experiments were not supported by epidemiology, which may be related to the existence of a window of sensitivity to environmental estrogen exposure over the human life course, where the consequences of exposure vary greatly from other times. This paper will introduce the main sources of environmental estrogens, their toxicity and mechanisms of action, the status of research on several representative types, and current monitoring and treatment methods. We also discussed the extent of the risks to human health dialectically in the context of laboratory and epidemiological findings, with a view to better addressing these chemicals to which we are constantly exposed.

Phytoestrogens, novel dietary supplements for breast cancer

While endocrine therapy is considered as an effective way to treat breast cancer, it still faces many challenges, such as drug resistance and individual discrepancy. Therefore, novel preventive and therapeutic modalities are still in great demand to decrease the incidence and mortality rate of breast cancer. Numerous studies suggested that G protein-coupled estrogen receptor (GPER), a membrane estrogen receptor, is a potential target for breast cancer prevention and treatment. It was also shown that not only endogenous estrogens can activate GPERs, but many phytoestrogens can also function as selective estrogen receptor modulators (SERMs) to interact GPERs. In this review, we discussed the possible mechanisms of GPERs pathways and shed a light of developing novel phytoestrogens based dietary supplements against breast cancers.

Destabilization of microrchidia family CW-type zinc finger 2 via the cyclin-dependent kinase 1-chaperone-mediated autophagy pathway promotes mitotic arrest and enhances cancer cellular sensitivity to microtubule-targeting agents

BACKGROUND

Microtubule-targeing agents (MTAs), such as paclitaxel (PTX) and vincristine (VCR), kill cancer cells through activtion of the spindle assembly checkpoint (SAC) and induction of mitotic arrest, but the development of resistance poses significant clinical challenges.

METHODS

Immunoblotting and RT-qPCR were used to investigate potential function and related mechanism of MORC2. Flow cytometry analyses were carried out to determine cell cycle distribution and apoptosis. The effect of MORC2 on cellular sensitivity to PTX and VCR was determined by immunoblotting, flow cytometry, and colony formation assays. Immunoprecipitation assays and immunofluorescent staining were utilized to investigate protein-protein interaction and protein co-localization.

RESULTS

Here, we identified microrchidia family CW-type zinc finger 2 (MORC2), a poorly characterized oncoprotein, as a novel regulator of SAC activation, mitotic progression, and resistance of cancer cells to PTX and VCR. Mechanically, PTX and VCR activate cyclin-dependent kinase 1, which in turn induces MORC2 phosphorylation at threonine 717 (T717) and T733. Phosphorylated MORC2 enhances its interation with HSPA8 and LAMP2A, two essential components of the chaperone-mediated autophagy (CMA) mechinery, resulting in its autophagic degradation. Degradation of MORC2 during mitosis leads to SAC activation through stabilizing anaphase promoting complex/cyclosome activator protein Cdc20 and facilitating mitotic checkpoint complex assembly, thus contributing to mitotic arrest induced by PTX and VCR. Notably, knockdown of MORC2 promotes mitotic arrest induced by PTX and VCR and enhances the sensitivity of cancer cells to PTX and VCR.

CONCLUSIONS

Collectively, these findings unveil a previously unrecognized function and regulatory mechanism of MORC2 in mitotic progression and resistance of cancer cells to MTAs. These results also provide a new clue for developing combined treatmentstrategy by targeting MORC2 in combination with MTAs against human cancer.

Protein degradation: expanding the toolbox to restrain cancer drug resistance

Despite significant progress in clinical management, drug resistance remains a major obstacle. Recent research based on protein degradation to restrain drug resistance has attracted wide attention, and several therapeutic strategies such as inhibition of proteasome with bortezomib and proteolysis-targeting chimeric have been developed. Compared with intervention at the transcriptional level, targeting the degradation process seems to be a more rapid and direct strategy. Proteasomal proteolysis and lysosomal proteolysis are the most critical quality control systems responsible for the degradation of proteins or organelles. Although proteasomal and lysosomal inhibitors (e.g., bortezomib and chloroquine) have achieved certain improvements in some clinical application scenarios, their routine application in practice is still a long way off, which is due to the lack of precise targeting capabilities and inevitable side effects. In-depth studies on the regulatory mechanism of critical protein degradation regulators, including E3 ubiquitin ligases, deubiquitylating enzymes (DUBs), and chaperones, are expected to provide precise clues for developing targeting strategies and reducing side effects. Here, we discuss the underlying mechanisms of protein degradation in regulating drug efflux, drug metabolism, DNA repair, drug target alteration, downstream bypass signaling, sustaining of stemness, and tumor microenvironment remodeling to delineate the functional roles of protein degradation in drug resistance. We also highlight specific E3 ligases, DUBs, and chaperones, discussing possible strategies modulating protein degradation to target cancer drug resistance. A systematic summary of the molecular basis by which protein degradation regulates tumor drug resistance will help facilitate the development of appropriate clinical strategies.

In silico design and validation of a novel multi-epitope vaccine candidate against structural proteins of Chikungunya virus using comprehensive immunoinformatics analyses

Chikungunya virus (CHIKV) is an emerging viral infectious agent with the potential of causing pandemic. There is neither a protective vaccine nor an approved drug against the virus. The aim of this study was design of a novel multi-epitope vaccine (MEV) candidate against the CHIKV structural proteins using comprehensive immunoinformatics and immune simulation analyses. In this study, using comprehensive immunoinformatics approaches, we developed a novel MEV candidate using the CHIKV structural proteins (E1, E2, 6 K, and E3). The polyprotein sequence was obtained from the UniProt Knowledgebase and saved in FASTA format. The helper and cytotoxic T lymphocytes (HTLs and CTLs respectively) and B cell epitopes were predicted. The toll-like receptor 4 (TLR4) agonist RS09 and PADRE epitope were employed as promising immunostimulatory adjuvant proteins. All vaccine components were fused using proper linkers. The MEV construct was checked in terms of antigenicity, allergenicity, immunogenicity, and physicochemical features. The docking of the MEV construct and the TLR4 and molecular dynamics (MD) simulation were also performed to assess the binding stability. The designed construct was non-allergen and was immunogen which efficiently stimulated immune responses using the proper synthetic adjuvant. The MEV candidate exhibited acceptable physicochemical features. Immune provocation included prediction of HTL, B cell, and CTL epitopes. The docking and MD simulation confirmed the stability of the docked TLR4-MEV complex. The high-level protein expression in the Escherichia coli (E. coli) host was observed through in silico cloning. The in vitro, in vivo, and clinical trial investigations are required to verify the findings of the current study.

HSPA8 Is a New Biomarker of Triple Negative Breast Cancer Related to Prognosis and Immune Infiltration

Objective. Triple negative breast cancer (TNBC) is a kind of cancer that endangers the lives of women all over the world in the 21st century. Heat shock protein member 8 (HSPA8) is the chaperone gene of the heat shock protein family. It is involved in many cellular functions. For example, it promotes the circulation between ATP and ADP, participates in protein folding, and can change the vitality of the cell and inhibit its growth. However, the abnormal expression of HSPA8 gene in TNBC and its diagnostic and prognostic significance still need to be further studied. Methods. First, we used related databases (such as TCGA, GEO, GTEx, ONCOMINE, TIMER2.0, UALCAN, HPA, STRING, CCLE, and Kaplan-Meier plotter databases) to analyze the relationship between HSPA8 and TNBC by bioinformatics. Then, the analysis using only a small part of the experimental work is used to explain our findings. For example, HSPA8 protein expression was evaluated by immunohistochemical method in TNBC tissues. Western blotting experiments were carried out to verify the results. Then, the clinicopathological characteristics of patients with TNBC were analyzed by R software and Cox regression analysis. On the basis, a nomogram is constructed to estimate the 1-, 3-, and 5-year overall survival (OS). The prognostic nomogram performance was calibrated and evaluated by the calibration curve and receiver operating characteristic (ROC) curve. Results. In the study, we analyzed the three GEO databases (including GSE86945, GSE106977, and GSE102088) and found that HSPA8 is one of the central genes of TNBC. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) researches indicated that HSPA8 was mainly involved in partner-mediated autophagy, mRNA catabolism, neutrophil activation, immune response, protein targeting, RNA splicing, RNA catabolism, and other biological processes. Next, we used bioinformatics technology to find that the expression level of HSPA8 in breast cancer (BC) and TNBC samples was significantly higher than that in normal breast tissues, which was determined by analyzing hospital patient samples and related experiments. In addition, the expression level of HSPA8 in BC and TNBC samples was significantly correlated with clinical indexes such as TNM stage. The Cox analysis revealed that the expression of HSPA8 in TNBC had significant clinical prognostic value. The results of nomogram and ROC test show that HSPA8 has significant predictive ability in TNBC. The results of immune infiltration of HSPA8 through the TIMER2.0 database showed that there was a significant correlation between HSPA8 and immune cell subsets. Conclusions. Our results show that the expression of HSPA8 in TNBC has important clinical diagnostic significance and clarify the potential molecular mechanism that promotes the evolution of TNBC. The high expression of HSPA8 may be related with the poor clinical outcome of TNBC. This helps to provide us with a new direction of TNBC targeted therapy.

Inhibition of MORC2 Mediates HDAC4 to Promote Cellular Senescence through p53/p21 Signaling Axis

(1) Background: Colorectal cancer (CRC) is a common gastrointestinal malignancy, accounting for the second largest gastrointestinal tumor. MORC2, a newly discovered chromatin remodeling protein, plays an important role in the biological processes of various cancers. However, the potential mechanistic role of MORC2 in promoting proliferation of CRC carcinoma remains unclear. (2) Methods: The Cancer Genome Atlas database was analyzed using bioinformatics to obtain gene expression and clinical prognosis data. The cell proliferation was assessed by CCK8 and EdU assays, as well as xenograft. SA-beta-gal staining, Western blot, and ELISA assay were using to assess the cell senescence and potential mechanism. (3) Results: Our data showed that MORC2 expression was elevated in CRC patients. Depletion of MORC2 inhibited cellular proliferation both in vivo and in vitro. Further studies showed that the depletion of MORC2 enhanced p21 and p53 expression through decreasing HDAC4 and increasing pro-inflammatory factors IL-6 and IL-8, thus, promoting cellular senescence. (4) Conclusions: We concluded that increased MORC2 expression in CRC might play a critical role in tumorigenesis by regulating the cellular senescence, in addition, MORC2 could be a novel biomarker for clinical outcomes and prognosis and a treatment target for CRC.

The TGF-β/SMAD Signaling Pathway Prevents Follicular Atresia by Upregulating MORC2

In mammals, female fertility is determined by the outcome of follicular development (ovulation or atresia). The TGF-β/SMAD signaling pathway is an important regulator of this outcome. However, the molecular mechanism by which the TGF-β/SMAD signaling pathway regulates porcine follicular atresia has not been fully elucidated. Microrchidia family CW-type zinc finger 2 (MORC2) is anovel epigenetic regulatory protein widely expressed in plants, nematodes, and mammals. Our previous studies showed that MORC2 is a potential downstream target gene of the TGF-β/SMAD signaling pathway. However, the role of MORC2 in porcine follicular atresia is unknown. To investigate this, qRT-PCR, western blotting, and TdT-mediated dUTP nick-end labeling were performed. Additionally, the luciferase activity assay was conductedto confirm that the TGF-β/SMAD signaling pathway regulates MORC2. Our results demonstrate that MORC2 is animportant anti-apoptotic molecule that prevents porcine follicular atresia via a pathway involving mitochondrial apoptosis, not DNA repair. Notably, this studyrevealsthat the TGF-β/SMAD signaling pathway inhibits porcine granulosa cell apoptosis by up-regulating MORC2. The transcription factor SMAD4 regulated the expression of MORC2 by binding to its promoter. Our results will help to reveal the mechanism underlying porcine follicular atresia and improve the reproductive efficiency of sows.

MORC2/β-catenin signaling axis promotes proliferation and migration of breast cancer cells

Although Microrchidia 2 (MORC2) is overexpressed in many types of human cancer, its role in breast cancer progression remains unknown. Here, we report that the chromatin remodeler MORC2 expression positively correlates with β-catenin expression in breast cancer cell lines and patients. Overexpression of MORC2 augmented the expression of β-catenin and its target genes, cyclin D1 and c-Myc. Consistent with these results, we found MORC2 knockdown resulted in decreased expression of β-catenin and its target genes. Surprisingly, we observed that c-Myc, the target gene of β-catenin, regulated the MORC2-β-catenin signaling axis through a feedback mechanism. We demonstrated that MORC2 regulates β-catenin expression and function by modulating the phosphorylation of AKT. In addition, we observed reduced proliferation and migration of MORC2 overexpressing breast cancer cells upon β-catenin inhibition. Overall, our results demonstrate that MORC2 promotes breast cancer cell proliferation and migration by regulating β-catenin signaling.

Microrchidia CW-Type Zinc Finger 2, a Chromatin Modifier in a Spectrum of Peripheral Neuropathies

Microrchidia CW-type zinc finger 2 (MORC2) gene encodes a protein expressed in all tissues and enriched in the brain. MORC2 protein is composed of a catalytic ATPase domain, three coil-coiled domains allowing dimerization or protein complex interaction, a zinc-finger CW domain allowing DNA interaction, and a CHROMO-like (CHRromatin Organization Modifier) domain. Recently, de novo or dominantly inherited heterozygous mutations have been associated with a spectrum of disorders affecting the peripheral nervous system such as the Charcot-Marie-Tooth disease, spinal muscular atrophy-like phenotype disorder, or a neurodevelopmental syndrome associated with developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy (DIGFAN). In this review, we detail the various mutations of MORC2 and their consequences on clinical manifestations. Possible genotype-phenotype correlations as well as intra and inter-family variability are discussed. MORC2 molecular functions such as transcriptional modulation, DNA damage repair, and lipid metabolism are then reviewed. We further discuss the impact of MORC2 mutations on the epigenetic landscape in the neuromuscular system and hypothesize probable pathophysiological mechanisms underlying the phenotypic variability observed.

Structural and Functional Attributes of Microrchidia Family of Chromatin Remodelers

Chromatin remodelers affect the spatio-temporal dynamics of global gene-expression by structurally modulating and/or reorganizing the chromatin. Microrchidia (MORC) family is a relatively new addition to the four well studied families of chromatin remodeling proteins. In this review, we discuss the current understanding of the structural aspects of human MORCs as well as their epigenetic functions. From a molecular and systems-level perspective, we explore their participation in phase-separated structures, possible influence on various biological processes through protein-protein interactions, and potential extra-nuclear roles. We describe how dysregulation/dysfunction of MORCs can lead to various pathological conditions. We conclude by emphasizing the importance of undertaking integrated efforts to obtain a holistic understanding of the various biological roles of MORCs.

HSP90 N-terminal inhibitors target oncoprotein MORC2 for autophagic degradation and suppress MORC2-driven breast cancer progression

Aims

MORC family CW‐type zinc finger 2 (MORC2), a GHKL‐type ATPase, is aberrantly upregulated in multiple types of human tumors with profound effects on cancer aggressiveness, therapeutic resistance, and clinical outcome, thus making it an attractive drug target for anticancer therapy. However, the antagonists of MORC2 have not yet been documented.

Methods and Results

We report that MORC2 is a relatively stable protein, and the N‐terminal homodimerization but not ATP binding and hydrolysis is crucial for its stability through immunoblotting analysis and Quantitative real‐time PCR. The N‐terminal but not C‐terminal inhibitors of heat shock protein 90 (HSP90) destabilize MORC2 in multiple cancer cell lines, and strikingly, this process is independent on HSP90. Mechanistical investigations revealed that HSP90 N‐terminal inhibitors disrupt MORC2 homodimer formation without affecting its ATPase activities, and promote its lysosomal degradation through the chaperone‐mediated autophagy pathway. Consequently, HSP90 inhibitor 17‐AAG effectively blocks the growth and metastatic potential of MORC2‐expressing breast cancer cells both in vitro and in vivo, and these noted effects are not due to HSP90 inhibition.

Conclusion

We uncover a previously unknown role for HSP90 N‐terminal inhibitors in promoting MORC2 degradation in a HSP90‐indepentent manner and support the potential application of these inhibitors for treating MORC2‐overexpressing tumors, even those with low or absent HSP90 expression. These results also provide new clue for further design of novel small‐molecule inhibitors of MORC2 for anticancer therapeutic application.

AUF1 protects against ferroptosis to alleviate sepsis-induced acute lung injury by regulating NRF2 and ATF3

BACKGROUND

The AU-rich element (ARE)-binding factor 1 (AUF1) acts as a switch for septic shock, although its underlying mechanisms remain largely unknown. In this study, we examined the biological significance and potential molecular mechanism of AUF1 in regulating ferroptosis in sepsis-induced acute lung injury (ALI).

METHODS

Alveolar epithelial cells (AECs) challenged with ferroptosis-inducing compounds and cecum ligation and puncture (CLP)-induced ALI were used as the in vitro and in vivo model, respectively. The stability of AUF1 and its degradation by ubiquitin-proteasome pathway were examined by cycloheximide chase analysis and co-immunoprecipitation assay. The regulation of AUF1 on nuclear factor E2-related factor 2 (NRF2) and activation transcription factor 3 (ATF3) was explored by RNA immunoprecipitation (RIP), RNA pull-down, and mRNA stability assays. Functionally, the effects of altering AUF1, NRF2 or ATF3 on ferroptosis in AECs or ALI mice were evaluated by measuring cell viability, lipid peroxidation, iron accumulation, and total glutathione level.

RESULTS

AUF1 was down-regulated in AECs challenged with ferroptosis-inducing compounds, both on mRNA and protein levels. The E3 ubiquitin ligase FBXW7 was responsible for protein degradation of AUF1 during ferroptosis. By up-regulating NRF2 and down-regulating ATF3, AUF1 antagonized ferroptosis in AECs in vitro. In the CLP-induced ALI model, the survival rate of AUF1 knockout mice was significantly reduced and the lung injuries were aggravated, which were related to the enhancement of lung ferroptosis.

CONCLUSIONS

FBXW7 mediates the ubiquitination and degradation of AUF1 in ferroptosis. AUF1 antagonizes ferroptosis by regulating NRF2 and ATF3 oppositely. Activating AUF1 pathway may be beneficial to the treatment of sepsis-induced ALI.

O-GlcNAcylation of MORC2 at threonine 556 by OGT couples TGF-β signaling to breast cancer progression

MORC family CW-type zinc finger 2 (MORC2) is a newly identified chromatin-remodeling enzyme involved in DNA damage response and gene transcription, and its dysregulation has been linked with Charcot-Marie-Tooth disease, neurodevelopmental disorder, and cancer. Despite its functional importance, how MORC2 is regulated remains enigmatic. Here, we report that MORC2 is O-GlcNAcylated by O-GlcNAc transferase (OGT) at threonine 556. Mutation of this site or pharmacological inhibition of OGT impairs MORC2-mediated breast cancer cell migration and invasion in vitro and lung colonization in vivo. Moreover, transforming growth factor-β1 (TGF-β1) induces MORC2 O-GlcNAcylation through enhancing the stability of glutamine-fructose-6-phosphate aminotransferase (GFAT), the rate-limiting enzyme for producing the sugar donor for OGT. O-GlcNAcylated MORC2 is required for transcriptional activation of TGF-β1 target genes connective tissue growth factor (CTGF) and snail family transcriptional repressor 1 (SNAIL). In support of these observations, knockdown of GFAT, SNAIL or CTGF compromises TGF-β1-induced, MORC2 O-GlcNAcylation-mediated breast cancer cell migration and invasion. Clinically, high expression of OGT, MORC2, SNAIL, and CTGF in breast tumors is associated with poor patient prognosis. Collectively, these findings uncover a previously unrecognized mechanistic role for MORC2 O-GlcNAcylation in breast cancer progression and provide evidence for targeting MORC2-dependent breast cancer through blocking its O-GlcNAcylation.

Identification of Genes Linking Natural Killer Cells to Apoptosis in Acute Myocardial Infarction and Ischemic Stroke

Natural killer (NK) cells are a type of innate lymphoid cell that are involved in the progression of acute myocardial infarction and ischemic stroke. Although multiple forms of programmed cell death are known to play important roles in these diseases, the correlation between NK cells and apoptosis-related genes during acute myocardial infarction and ischemic stroke remains unclear. In this study, we explored the distinct patterns of NK cell infiltration and apoptosis during the pathological progression of acute myocardial infarction and ischemic stroke using mRNA expression microarrays from the Gene Expression Omnibus database. Since the abundance of NK cells correlated positively with apoptosis in both diseases, we further examined the correlation between NK cell abundance and the expression of apoptosis-related genes. Interestingly, APAF1 and IRAK3 expression correlated negatively with NK cell abundance in both acute myocardial infarction and ischemic stroke, whereas ATM, CAPN1, IL1B, IL1R1, PRKACA, PRKACB, and TNFRSF1A correlated negatively with NK cell abundance in acute myocardial infarction. Together, these findings suggest that these apoptosis-related genes may play important roles in the mechanisms underlying the patterns of NK cell abundance and apoptosis in acute myocardial infarction and ischemic stroke. Our study, therefore, provides novel insights for the further elucidation of the pathogenic mechanism of ischemic injury in both the heart and the brain, as well as potential useful therapeutic targets.

MORC protein family-related signature within human disease and cancer

The microrchidia (MORC) family of proteins is a highly conserved nuclear protein superfamily, whose members contain common domain structures (GHKL-ATPase, CW-type zinc finger and coiled-coil domain) yet exhibit diverse biological functions. Despite the advancing research in previous decades, much of which focuses on their role as epigenetic regulators and in chromatin remodeling, relatively little is known about the role of MORCs in tumorigenesis and pathogenesis. MORCs were first identified as epigenetic regulators and chromatin remodelers in germ cell development. Currently, MORCs are regarded as disease genes that are involved in various human disorders and oncogenes in cancer progression and are expected to be the important biomarkers for diagnosis and treatment. A new paradigm of expanded MORC family function has raised questions regarding the regulation of MORCs and their biological role at the subcellular level. Here, we systematically review the progress of researching MORC members with respect to their domain architectures, diverse biological functions, and distribution characteristics and discuss the emerging roles of the aberrant expression or mutation of MORC family members in human disorders and cancer development. Furthermore, the illustration of related mechanisms of the MORC family has made MORCs promising targets for developing diagnostic tools and therapeutic treatments for human diseases, including cancers.

Chaperone-mediated autophagy and disease: Implications for cancer and neurodegeneration

Chaperone-mediated autophagy (CMA) is a proteolytic process whereby selected intracellular proteins are degraded inside lysosomes. Owing to its selectivity, CMA participates in the modulation of specific regulatory proteins, thereby playing an important role in multiple cellular processes. Studies conducted over the last two decades have enabled the molecular characterization of this autophagic pathway and the design of specific experimental models, and have underscored the importance of CMA in a range of physiological processes beyond mere protein quality control. Those findings also indicate that decreases in CMA function with increasing age may contribute to the pathogenesis of age-associated diseases, including neurodegeneration and cancer. In the context of neurological diseases, CMA impairment is thought to contribute to the accumulation of misfolded/aggregated proteins, a process central to the pathogenesis of neurodegenerative diseases. CMA therefore constitutes a potential therapeutic target, as its induction accelerates the clearance of pathogenic proteins, promoting cell survival. More recent evidence has highlighted the important and complex role of CMA in cancer biology. While CMA induction may limit tumor development, experimental evidence also indicates that inhibition of this pathway can attenuate the growth of established tumors and improve the response to cancer therapeutics. Here, we describe and discuss the evidence supporting a role of impaired CMA function in neurodegeneration and cancer, as well as future research directions to evaluate the potential of this pathway as a target for the prevention and treatment of these diseases.

Morc2a p.S87L mutant mice develop peripheral and central neuropathies associated with neuronal DNA damage and apoptosis

The microrchidia (MORC)-family CW-type zinc finger 2 (MORC2) gene is related to DNA repair, adipogenesis and epigenetic silencing via the human silencing hub (HUSH) complex. MORC2 missense mutation is known to cause peripheral neuropathy of Charcot-Marie-Tooth disease type 2 Z (CMT2Z). However, there have been reports of peripheral and central neuropathy in patients, and the disease has been co-categorized with developmental delay, impaired growth, dysmorphic facies and axonal neuropathy (DIGFAN). The etiology of MORC2 mutation-mediated neuropathy remains uncertain. Here, we established and analyzed Morc2a p.S87L mutant mice. Morc2a p.S87L mice displayed the clinical symptoms expected in human CMT2Z patients, such as axonal neuropathy and skeletal muscle weakness. Notably, we observed severe central neuropathy with cerebella ataxia, cognition disorder and motor neuron degeneration in the spinal cord, and this seemed to be evidence of DIGFAN. Morc2a p.S87L mice exhibited an accumulation of DNA damage in neuronal cells, followed by p53/cytochrome c/caspase 9/caspase 3-mediated apoptosis. This study presents a new mouse model of CMT2Z and DIGFAN with a Morc2a p.S87L mutation. We suggest that neuronal apoptosis is a possible target for therapeutic approach in MORC2 missense mutation. This article has an associated First Person interview with the first author of the paper.

MORC2 Interactome: Its Involvement in Metabolism and Cancer

Microrchidia 2 (MORC2) is an emerging chromatin modifier with a role in chromatin remodeling and epigenetic regulation. MORC2 is found to be upregulated in most cancers, playing a significant role in tumorigenesis and tumor metastasis. Recent studies have demonstrated that MORC2 is a scaffolding protein, which interacts with the proteins involved in DNA repair, chromatin remodeling, lipogenesis, and glucose metabolism. In this review, we discuss the domain architecture and cellular and subcellular localization of MORC2. Further, we highlight MORC2-specific interacting partners involved in metabolic reprogramming and other pathological functions such as cancer progression and metastasis.

PI3K/AKT phosphorylation activates ERRα by upregulating PGC‑1α and PGC‑1β in gallbladder cancer

The nuclear estrogen‑related receptor‑α (ERRα) is an orphan receptor that has been identified as a transcriptional factor. Peroxisome proliferator‑activated receptor‑γ (PPARγ) coactivator‑1‑α (PGC‑1α) and PPARγ coactivator‑1‑β (PGC‑1β) act as the co‑activators of ERRα. Our previous study reported that activated ERRα promoted the invasion and proliferation of gallbladder cancer cells by promoting PI3K/AKT phosphorylation. Therefore, the aim of the current study was to investigate whether PI3K/AKT phosphorylation could enhance ERRα activity in a positive feedback loop. LY294002 and insulin‑like growth factor I (IGF‑I) were used to inhibit and promote PI3K/AKT phosphorylation, respectively. A 3X ERE‑TATA luciferase reporter was used to measure ERRα activity. The present study found that LY294002 inhibited PI3K/AKT phosphorylation, decreased the proliferation and invasion of NOZ cells and suppressed the activity of ERRα. Conversely, IGF‑I induced PI3K/AKT phosphorylation, promoted the proliferation and invasion of NOZ cells and enhanced the activity of ERRα. The protein expression levels of PGC‑1α and PGC‑1β were elevated and reduced by IGF‑I and LY294002, respectively. Moreover, knockdown of PGC‑1α and PGC‑1β antagonized ERRα activation, which was enhanced by PI3K/AKT phosphorylation. Taken together, the present study demonstrated that PI3K/AKT phosphorylation triggered ERRα by upregulating the expression levels of PGC‑1α and PGC‑1β in NOZ cells.

PI3K/AKT phosphorylation activates ERRα by upregulating PGC‑1α and PGC‑1β in gallbladder cancer

The nuclear estrogen‑related receptor‑α (ERRα) is an orphan receptor that has been identified as a transcriptional factor. Peroxisome proliferator‑activated receptor‑γ (PPARγ) coactivator‑1‑α (PGC‑1α) and PPARγ coactivator‑1‑β (PGC‑1β) act as the co‑activators of ERRα. Our previous study reported that activated ERRα promoted the invasion and proliferation of gallbladder cancer cells by promoting PI3K/AKT phosphorylation. Therefore, the aim of the current study was to investigate whether PI3K/AKT phosphorylation could enhance ERRα activity in a positive feedback loop. LY294002 and insulin‑like growth factor I (IGF‑I) were used to inhibit and promote PI3K/AKT phosphorylation, respectively. A 3X ERE‑TATA luciferase reporter was used to measure ERRα activity. The present study found that LY294002 inhibited PI3K/AKT phosphorylation, decreased the proliferation and invasion of NOZ cells and suppressed the activity of ERRα. Conversely, IGF‑I induced PI3K/AKT phosphorylation, promoted the proliferation and invasion of NOZ cells and enhanced the activity of ERRα. The protein expression levels of PGC‑1α and PGC‑1β were elevated and reduced by IGF‑I and LY294002, respectively. Moreover, knockdown of PGC‑1α and PGC‑1β antagonized ERRα activation, which was enhanced by PI3K/AKT phosphorylation. Taken together, the present study demonstrated that PI3K/AKT phosphorylation triggered ERRα by upregulating the expression levels of PGC‑1α and PGC‑1β in NOZ cells.

Progress of Breast Cancer basic research in China

Breast cancer is the most commonly diagnosed and the most lethal cancer in females both in China and worldwide. Currently, the origin of cancer stem cells, the heterogeneity of cancer cells, the mechanism of cancer metastasis and drug resistance are the most important issues that need to be addressed. Chinese investigators have recently made new discoveries in basic breast cancer researches, especially regarding cancer stem cells, cancer metabolism, and microenvironments. These efforts have led to a deeper understanding of drug resistance and metastasis and have also indicated new biomarkers and therapeutic targets. These findings emphasized the importance of the cancer stem cells for targeted therapy. In this review, we summarized the latest important findings in this field in China.

MicroRNA-27a promotes tumorigenesis in tongue squamous cell carcinoma by enhancing proliferation, migration and suppressing apoptosis

BACKGROUND

Tongue squamous cell carcinoma (TSCC) is a major subtype of head and neck squamous cell carcinoma (HNSCC), which is an intractable cancer with a poor prognosis. Studies have shown that microRNAs (miRNAs) play an important role in TSCC biology. However, the expression and functions of miRNAs in TSCC remain unclear.

METHODS

The non-coding RNA profiles of TSCC were downloaded from the GEO database. WGCNA (Weighted gene co-expression network analysis) and differential expression miRNA (DE-miRNA) analyses were employed to identify key candidate miRNAs. miRNA expression was detected using RT-qPCR analysis. The target genes of key miRNAs were predicted. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to explore the potential functions and pathways of key miRNA. miRNA inhibitor was transfected to detect the function of miRNA. The effect of miRNA deregulation on TSCC cell proliferation and apoptosis was investigated using MTS, Annexin V-FITC/PI double staining, and flow cytometry assays.

RESULTS

miR-27a was a key miRNA in TSCC, which was significantly up-regulated in both Cal-27 cells and malignant tissues from the TSCC patients. In addition, functional analysis showed that miR-27a was involved in the regulation of the MAPK, ERBB, and Jak-STAT signaling pathways. Moreover, RHOA and PRKACA were potential target genes of miR-27a, suggesting them as possible mediators of the tumor-promoting effect of miR-27a. Moreover, downregulation of miR-27a inhibited cell proliferation and facilitated cell apoptosis in Cal-27 cells.

CONCLUSION

Our findings strongly suggest that miR-27a could promote the tumorigenesis and development of TSCC, which makes it a potential new diagnostic marker and therapeutic target for TSCC.

Chaperone Mediated Autophagy Substrates and Components in Cancer

Chaperone-mediated autophagy (CMA) represents a specific way of lysosomal protein degradation and contrary to macro and microautophagy is independent of vesicles formation. The role of CMA in different physiopathological processes has been studied for several years. In cancer, alterations of the CMA principal components, Hsc70 and Lamp2A protein and mRNA levels, have been described in malignant cells. However, changes in the expression levels of these CMA components are not always associated with changes in CMA activity and their biological significance must be carefully interpreted case by case. The objective of this review is to discuss whether altering the CMA activity, CMA substrates or CMA components is accurate to avoid cancer progression. In particular, this review will discuss about the evidences in which alterations CMA components Lamp2A and Hsc70 are associated or not with changes in CMA activity in different cancer types. This analysis will help to better understand the role of CMA activity in cancer and to elucidate whether CMA can be considered as target for therapeutics. Further, it will help to define whether the attention of the investigation should be focused on Lamp2A and Hsc70 because they can have an independent role in cancer progression beyond of their participation in altered CMA activity.

MicroRNA-375 exacerbates knee osteoarthritis through repressing chondrocyte autophagy by targeting ATG2B

Objective: This study aimed to explore the underlying mechanism of miR-375 in exacerbating osteoarthritis (OA).

Results: MiR-375 expression were upregulated in OA cartilage tissues, whereas ATG2B expression was decreased. MiR-375 targeted ATG2B 3’ UTR and inhibited its expression in the chondrocytes, and then suppressed autophagy and promoted endoplasmic reticulum stress (ERs). The apoptosis rate of chondrocytes was increased after being transfected with miR-375 mimics. In vivo results further verified that inhibition of miR-375 could relieve OA-related symptoms.

Conclusion: miR-375 can inhibit the expression of ATG2B in chondrocytes, suppress autophagy and promote the ERs. It suggests that miR-375 could be considered to be a key therapy target for OA.

Methods: Differential expression analyses for mRNA and miRNA microarray datasets from ArrayExpress were performed. MiR-375 and ATG2B expressions in cartilage tissues were detected by qRT-PCR. Dual luciferase assay was applied to verify the targeting relationship between ATG2B and miR-375. In vitro, the role of miR-375 on chondrocyte autophagy and ERs was investigated by western blot and immunofluorescence. The apoptotic rate was quantified by flow cytometry. In vivo, OA mice model was established, HE and Safranin O and Fast Green staining, as well as the OARSI and modified Mankin scores, were applied to measure the OA cartilage damage severity.