VGLL4 interacts with STAT3 to function as a tumor suppressor in triple-negative breast cancer

Maternal vgll4a regulates zebrafish epiboly through Yap1 activity

Gastrulation in zebrafish embryos commences with the morphogenetic rearrangement of blastodermal cells, which undergo a coordinated spreading from the animal pole to wrap around the egg at the vegetal pole. This rearrangement, known as epiboly, relies on the orchestrated activity of maternal transcripts present in the egg, compensating for the gradual activation of the zygotic genome. Epiboly involves the mechano-transducer activity of yap1 but what are the regulators of yap1 activity and whether these are maternally or zygotically derived remain elusive. Our study reveals the crucial role of maternal vgll4a, a proposed Yap1 competitor, during zebrafish epiboly. In embryos lacking maternal/zygotic vgll4a (MZvgll4a), the progression of epiboly and blastopore closure is delayed. This delay is associated with the ruffled appearance of the sliding epithelial cells, decreased expression of yap1-downstream targets and transient impairment of the actomyosin ring at the syncytial layer. Our study also shows that, rather than competing with yap1, vgll4a modulates the levels of the E-cadherin/β-catenin adhesion complex at the blastomeres' plasma membrane and hence their actin cortex distribution. Taking these results together, we propose that maternal vgll4a acts at epiboly initiation upstream of yap1 and the E-cadherin/β-catenin adhesion complex, contributing to a proper balance between tissue tension/cohesion and contractility, thereby promoting a timely epiboly progression.

Hypoxia-sensing VGLL4 promotes LDHA-driven lactate production to ameliorate neuronal dysfunction in a cellular model relevant to Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease where abnormal amyloidogenic processing of amyloid-β precursor protein (APP) occurs and has been linked to neuronal dysfunction. Hypometabolism of glucose in the brain can lead to synaptic loss and neuronal death, which in turn exacerbates energy deficiency and amyloid-β peptide (Aβ) accumulation. Lactate produced by anaerobic glycolysis serves as an energy substrate supporting neuronal function and facilitating neuronal repair. Vestigial-like family member 4 (VGLL4) has been recognized as a key regulator of the hypoxia-sensing pathway. However, the role of VGLL4 in AD remains unexplored. Here, we reported that the expression of VGLL4 protein was significantly decreased in the brain tissue of AD model mice and AD model cells. We further found that overexpression of VGLL4 reduced APP amyloidogenic processing and ameliorated neuronal synaptic damage. Notably, we identified a compromised hypoxia-sensitive capability of LDHA regulated by VGLL4 in the context of AD. Upregulation of VGLL4 increased the response of LDHA to hypoxia and enhanced the expression levels of LDHA and lactate by inhibiting the ubiquitination and degradation of LDHA. Furthermore, the inhibition of lactate production by using sodium oxamate, an inhibitor of LDHA, suppressed the neuroprotective function of VGLL4 by increasing APP amyloidogenic processing. Taken together, our findings demonstrate that VGLL4 exerts a neuroprotective effect by upregulating LDHA expression and consequently promoting lactate production. Thus, this study suggests that VGLL4 may be a novel player involved in molecular mechanisms relevant for ameliorating neurodegeneration.

The molecular basis of nutrient sensing and signalling by mTORC1 in metabolism regulation and disease

The Ser/Thr kinase mechanistic target of rapamycin (mTOR) is a central regulator of cellular metabolism. As part of mTOR complex 1 (mTORC1), mTOR integrates signals such as the levels of nutrients, growth factors, energy sources and oxygen, and triggers responses that either boost anabolism or suppress catabolism. mTORC1 signalling has wide-ranging consequences for the growth and homeostasis of key tissues and organs, and its dysregulated activity promotes cancer, type 2 diabetes, neurodegeneration and other age-related disorders. How mTORC1 integrates numerous upstream cues and translates them into specific downstream responses is an outstanding question with major implications for our understanding of physiology and disease mechanisms. In this Review, we discuss recent structural and functional insights into the molecular architecture of mTORC1 and its lysosomal partners, which have greatly increased our mechanistic understanding of nutrient-dependent mTORC1 regulation. We also discuss the emerging involvement of aberrant nutrient-mTORC1 signalling in multiple diseases.

Lycorine weakens tamoxifen resistance of breast cancer via abrogating HAGLR-mediated epigenetic suppression on VGLL4 by DNMT1

Much is known about the significance of lycorine, a natural alkaloid, in combating various types of cancer, including breast cancer (BC), but whether it participates in regulating tamoxifen (TAM) resistance and its underlying mechanism remain to be elucidated. Tamoxifen-resistant (TAMR) BC cells were first established by continuously exposed to increasing concentrations of TAM. Levels of targeted gene including HOXD antisense growth-associated lncRNA (HAGLR) and Vestigial like family member 4 (VGLL4) were analyzed by qRT-PCR and western blot, respectively. Cell proliferation ability was assessed by MTT and EdU assays. Flow cytometry was carried out to evaluate the apoptosis. VGLL4 promoter methylation was examined using methylation specific PCR (MSP). The role of HAGLR acting on the expression of VGLL4 via DNA hypermethylation was confirmed by RNA immunoprecipitation (RIP). Here, we reported that lycorine administration reduced the survival ratio of TAMR BC cells, decreased the IC₅₀ of TAM, and strengthened TAM-induced apoptosis. HAGLR, observed to be highly expressed in TAMR BC cells, was identified to be a downstream effector of lycorine, of which overexpression abolished lycorine-mediated TAMR inhibition. VGLL4 served as a target of HAGLR in regulating lycorine-mediated suppression on tamoxifen resistance of TAMR BC cells. Mechanistically, HAGLR epigenetically suppressed VGLL4 expression via DNA methyltransferase 1 (DNMT1)-mediated DNA hypermethylation. Taken together, our data highlights the pivotal role of lycorine in TAM resistance of BC, which may provide a potential agent for improving the effectiveness and efficacy of BC resistance.

Somatic mosaicism in the diseased brain

It is hard to believe that all the cells of a human brain share identical genomes. Indeed, single cell genetic studies have demonstrated intercellular genomic variability in the normal and diseased brain. Moreover, there is a growing amount of evidence on the contribution of somatic mosaicism (the presence of genetically different cell populations in the same individual/tissue) to the etiology of brain diseases. However, brain-specific genomic variations are generally overlooked during the research of genetic defects associated with a brain disease. Accordingly, a review of brain-specific somatic mosaicism in disease context seems to be required. Here, we overview gene mutations, copy number variations and chromosome abnormalities (aneuploidy, deletions, duplications and supernumerary rearranged chromosomes) detected in the neural/neuronal cells of the diseased brain. Additionally, chromosome instability in non-cancerous brain diseases is addressed. Finally, theoretical analysis of possible mechanisms for neurodevelopmental and neurodegenerative disorders indicates that a genetic background for formation of somatic (chromosomal) mosaicism in the brain is likely to exist. In total, somatic mosaicism affecting the central nervous system seems to be a mechanism of brain diseases.

Microbiota-derived tryptophan metabolites in vascular inflammation and cardiovascular disease

The essential amino acid tryptophan (Trp) is metabolized by gut commensals, yielding in compounds that affect innate immune cell functions directly, but also acting on the aryl hydrocarbon receptor (AHR), thus regulating the maintenance of group 3 innate lymphoid cells (ILCs), promoting T helper 17 (TH17) cell differentiation, and interleukin-22 production. In addition, microbiota-derived Trp metabolites have direct effects on the vascular endothelium, thus influencing the development of vascular inflammatory phenotypes. Indoxyl sulfate was demonstrated to promote vascular inflammation, whereas indole-3-propionic acid and indole-3-aldehyde had protective roles. Furthermore, there is increasing evidence for a contributory role of microbiota-derived indole-derivatives in blood pressure regulation and hypertension. Interestingly, there are indications for a role of the kynurenine pathway in atherosclerotic lesion development. Here, we provide an overview on the emerging role of gut commensals in the modulation of Trp metabolism and its influence in cardiovascular disease development.

Multi-omics analyses of airway host-microbe interactions in chronic obstructive pulmonary disease identify potential therapeutic interventions

The mechanistic role of the airway microbiome in chronic obstructive pulmonary disease (COPD) remains largely unexplored. We present a landscape of airway microbe-host interactions in COPD through an in-depth profiling of the sputum metagenome, metabolome, host transcriptome and proteome from 99 patients with COPD and 36 healthy individuals in China. Multi-omics data were integrated using sequential mediation analysis, to assess in silico associations of the microbiome with two primary COPD inflammatory endotypes, neutrophilic or eosinophilic inflammation, mediated through microbial metabolic interaction with host gene expression. Hypotheses of microbiome-metabolite-host interaction were identified by leveraging microbial genetic information and established metabolite-human gene pairs. A prominent hypothesis for neutrophil-predominant COPD was altered tryptophan metabolism in airway lactobacilli associated with reduced indole-3-acetic acid (IAA), which was in turn linked to perturbed host interleukin-22 signalling and epithelial cell apoptosis pathways. In vivo and in vitro studies showed that airway microbiome-derived IAA mitigates neutrophilic inflammation, apoptosis, emphysema and lung function decline, via macrophage-epithelial cell cross-talk mediated by interleukin-22. Intranasal inoculation of two airway lactobacilli restored IAA and recapitulated its protective effects in mice. These findings provide the rationale for therapeutically targeting microbe-host interaction in COPD.

Oral administration of asparagine and 3-indolepropionic acid prolongs survival time of rats with traumatic colon injury

BACKGROUND

Traumatic colon injury (TCI) is a common disease during wartime. Prolongation of posttraumatic survival time is an effective approach to patient outcome improvement. However, there is a lack of basic research in this field. This study aimed to elucidate the mechanisms underlying TCI progression and to develop novel regimens to buy time for TCI patients on the battlefield.

METHODS

A total of 669 Sprague-Dawley rats were used in this study. Surgical colon incision was performed to generate the TCI rat model. The landscape of colon microbiota compositions was depicted using 16S rRNA sequencing and metabolites in the intestinal contents were detected by metabolomics profiling. The signaling transduction in the intestinal epithelium was investigated using antibody microarrays and Western blotting. The enzyme-linked immunosorbent assay was conducted to measure the levels of interleukin-6 and tumor necrosis factor-α in intestines and plasma for the detection of inflammatory responses. Diamine oxidase, D-lactate and endotoxin in plasma and protein expression of zonula occludens 1 and occludin were selected as the indicators of intestinal barrier permeability. To investigate alterations of microbiota symbiosis, the relative abundances of specific bacterial genera were detected using quantitative real-time PCR.

RESULTS

As a type of lethal injury, TCI induced acute disruption of intestinal homeostasis, characterized by inflammatory responses, intestinal barrier hyperpermeability and microbiota dysbiosis (P < 0.05). Significant alterations in bacterial metabolic patterns were detected with decreases in many metabolites. After a series of screenings, we found that oral administration of asparagine (Asn) and 3-indolepropionic acid (IPA) effectively prolonged posttraumatic survival time [Asn plus IPA vs. Vehicle: hazard ratio (HR) = 0.105, 95% CI 0.031-0.356, P = 0.0003] and restored intestinal homeostasis in TCI rats (P < 0.05). Mechanistically, this combinational strategy protected the rats against TCI through synergistic activation of Akt signaling in the intestinal epithelium (P < 0.05).

CONCLUSIONS

Abrupt dysregulation of intestinal homeostasis plays a critical role in the progression toward TCI-induced death. Oral administration of Asn plus IPA may serve as an effective regimen to restore intestinal functions and prolong the posttraumatic survival time.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.

Critical role of VGLL4 in the regulation of chronic normobaric hypoxia-induced pulmonary hypertension in mice

Pulmonary hypertension (PH), a rare but deadly cardiopulmonary disorder, is characterized by extensive remodeling of pulmonary arteries resulting from enhancement of pulmonary artery smooth muscle cell proliferation and suppressed apoptosis; however, the underlying pathophysiological mechanisms remain largely unknown. Recently, epigenetics has gained increasing prominence in the development of PH. We aimed to investigate the role of vestigial-like family member 4 (VGLL4) in chronic normobaric hypoxia (CNH)-induced PH and to address whether it is associated with epigenetic regulation. The rodent model of PH was established by CNH treatment (10% O₂ , 23 hours/day). Western blot, quantitative reverse transcription polymerase chain reaction, immunofluorescence, immunoprecipitation, and adeno-associated virus tests were performed to explore the potential mechanisms involved in CNH-induced PH in mice. VGLL4 expression was upregulated and correlated with CNH in PH mouse lung tissues in a time-dependent manner. VGLL4 colocalized with α-smooth muscle actin in cultured pulmonary arterial smooth muscle cells (PASMCs), and VGLL4 immunoactivity was increased in PASMCs following hypoxia exposure in vitro. VGLL4 knockdown attenuated CNH-induced PH and pulmonary artery remodeling by blunting signal transducer and activator of transcription 3 (STAT3) signaling; conversely, VGLL4 overexpression exacerbated the development of PH. CNH enhanced the acetylation of VGLL4 and increased the interaction of ac-H3K9/VGLL4 and ac-H3K9/STAT3 in the lung tissues, and levels of ac-H3K9, p-STAT3/STAT3, and proliferation-associated protein levels were markedly up-regulated, whereas apoptosis-related protein levels were significantly downregulated, in the lung tissues of mice with CNH-induced PH. Notably, abrogation of VGLL4 acetylation reversed CNH-induced PH and pulmonary artery remodeling and suppressed STAT3 signaling. Finally, STAT3 knockdown alleviated CNH-induced PH. In conclusion, VGLL4 acetylation upregulation could contribute to CNH-induced PH and pulmonary artery remodeling via STAT3 signaling, and abrogation of VGLL4 acetylation reversed CNH-induced PH. Pharmacological or genetic deletion of VGLL4 might be a potential target for therapeutic interventions in CNH-induced PH.

Precision Therapy for Epilepsy Related to Brain Malformations

Malformations of cortical development (MCDs) represent a range of neurodevelopmental disorders that are collectively common causes of developmental delay and epilepsy, especially refractory childhood epilepsy. Initial treatment with antiseizure medications is empiric, and consideration of surgery is the standard of care for eligible patients with medically refractory epilepsy. In the past decade, advances in next generation sequencing technologies have accelerated progress in understanding the genetic etiologies of MCDs, and precision therapies for focal MCDs are emerging. Notably, mutations that lead to abnormal activation of the mammalian target of rapamycin (mTOR) pathway, which provides critical control of cell growth and proliferation, have emerged as a common cause of malformations. These include tuberous sclerosis complex (TSC), hemimegalencephaly (HME), and some types of focal cortical dysplasia (FCD). TSC currently represents the best example for the pathway from gene discovery to relatively safe and efficacious targeted therapy for epilepsy related to MCDs. Based on extensive pre-clinical and clinical data, the mTOR inhibitor everolimus is currently approved for the treatment of focal refractory seizures in patients with TSC. Although clinical studies are just emerging for FCD and HME, we believe the next decade will bring significant advancements in precision therapies for epilepsy related to these and other MCDs.

SWIM domain protein ZSWIM4 is required for JAK2 inhibition resistance in breast cancer

AIMS

Janus kinase 2 (JAK2)/signal transducer and activator of transcription (STAT) signaling plays a critical role in the progression of breast cancer. However, a small part of tumor cells survived from the killing effect of JAK2 inhibitor. We aimed to find out the mechanism of drug resistance in breast cancer cells and develop new therapeutic strategies.

MATERIALS AND METHODS

The anti-tumor effect of TG101209 in breast cancer cells was confirmed by cell counting kit 8 and flow cytometry. Western blotting was used to determine the up-regulation of zinc finger SWIM-type containing 4 (ZSWIM4) induced by TG101209. In vitro and in vivo experiments were performed to evaluate the role of ZSWIM4 in the resistance of breast cancer cells to TG101209. Through the determination and analysis of 50% inhibiting concentration (IC₅₀) curves, the effect of combination therapy was confirmed.

KEY FINDINGS

Our data indicate that the elevated expression of ZSWIM4 contributes to JAK2 inhibition resistance, as knockdown of ZSWIM4 significantly enhances the sensitivity of breast cancer cells to TG101209 and over-expression of this gene mitigates the killing effect. Furthermore, the expression of vitamin D receptor (VDR) and utilization of 1α,25-(OH)2VD3 is decreased in ZSWIM4-knockdown breast cancer cells. VDR-silencing or GW0742-mediated blockade of VDR activity can partially reverse the JAK2 inhibition resistance.

SIGNIFICANCE

Our data implicated that ZSWIM4 might be an inducible resistance gene of JAK2 inhibition in breast cancer cells. The combination of JAK2 inhibitor and VDR inhibitor may achieve better coordinated therapeutic effect in breast cancer.

Silencing miR-454 suppresses cell proliferation, migration and invasion via directly targeting MECP2 in renal cell carcinoma

Renal cell cancer (RCC) is one of the most common malignant tumors of the urinary system. MicroRNA-454 (miR-454) has been reported to play an important role in various cancer progressions, such as hepatocellular carcinoma, breast cancer and glioblastoma. Nevertheless, its effect on RCC still remains unknown. We aimed to investigate the biological function and underlying mechanisms of miR-454 in RCC. The expressions of miR-454 and MECP2 in RCC tissues were assessed using data from TCGA database and our own clinical samples. Functional experiments Cell Counting Kit-8 (CCK-8), colony formation, wound healing and Transwell assays were applied to detect the effects of miR-454 and MECP2 in RCC. The interaction between miR-454 and MECP2 was assessed by western blot and luciferase reporter assays. MiR-454 was upregulated in RCC tissues and cell lines compared with matched adjacent normal tissues and the normal kidney tubular epithelial cell line HK-2. MiR-454 inhibition and methyl-CpG binding protein 2 (MECP2) overexpression could both decrease the proliferative, migrative and invasive abilities of RCC cells. Higher expression of miR-454 predicted a poor overall survival (OS) (HR: 1.8; P < 0.05), while MECP2 level was positively related with RCC OS (HR: 0.55; P < 0.05) and disease-free survival (HR: 0.56; P < 0.05). Mechanistically, we showed that miR-454 could directly target the downstream gene MECP2. Our findings indicated that miR-454 accelerates RCC progression via suppressing MECP2 expression, which may provide a novel potential target of RCC treatment in the future.

Multiple Roles of Vestigial-Like Family Members in Tumor Development

Vestigial-like family (VGLL) members are mammalian orthologs of vestigial gene in Drosophila, and they consist of four homologs (VGLL1–4). VGLL members have TDU motifs that are binding regions to TEA/ATSS-DNA-binding domain transcription factor (TEAD). Through TDU motifs, VGLL members act as transcriptional cofactors for TEAD. VGLL1-3 have single TDU motif, whereas VGLL4 has two tandem TDU motifs, suggesting that VGLL4 has distinct molecular functions among this family. Although molecular and physiological functions of VGLL members are still obscure, emerging evidence has shown that these members are involved in tumor development. Gene alterations and elevated expression of VGLL1-3 were observed in various types of tumors, and VGLL1-3 have been shown to possess tumorigenic functions. In contrast, down-regulation of VGLL4 was detected in various tumors, and the tumor-suppressing role of VGLL4 has been demonstrated. In this review, we summarize the recently identified multiple roles of VGLL members in tumor development and provide important and novel insights regarding tumorigenesis.

Exosomal release of microRNA-454 by breast cancer cells sustains biological properties of cancer stem cells via the PRRT2/Wnt axis in ovarian cancer

AIMS

Cancer-derived exosomes carrying tumor-derived molecules such as miRNAs and proteins related to various phenotypes have been detected in both the bloodstream and other biofluids of patients with different cancers. Thus, our main purpose here was to determine the role of the exosomal microRNA-454 (miR-454) derived by MDA-MB-231 in self-renewal of cancer stem cells (CSCs) in ovarian cancer (OC).

MATERIALS AND METHODS

Extraction of MDA-MB-231 cells-derived exosomes (231-derived exosomes) was conducted to treat CD44+/CD133+ SKOV3 and CoC1 cells to observe cell growth and stemness. Next, the differentially expressed miRNAs in SKOV3 cells after exosome treatment were filtered using microarray analysis. Subsequently, the cell viability was detected after reducing the exosomal miR-454 and the addition of a Wnt pathway inhibitor C59. Finally, the pro-tumorigenic function of exosomes on OC cells in vivo was investigated.

KEY FINDINGS

After co-culture with 231-derived exosomes, the stemness of CSCs were promoted. Subsequently, the reduction of exosomal miR-454 weakened the roles of exosomes on cell stemness. Proline-rich transmembrane protein 2 (PRRT2) was substantiated as a target gene of miR-454 in SKOV3 and CoC1 cells. C59 reversed the repressive role of exosomes in stemness of CSCs. When being evaluated in a mouse model, exosomal miR-454 led to an efficacious effect in suppressing the tumor weight and volume in vivo.

SIGNIFICANCE

Altogether, 231-derived exosomes carrying miR-454 disrupted the Wnt pathway by targeting PRRT2, thereby promoting CSC stemness in vitro and OC cell growth in vivo.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.