N6-methyladenosine-driven miR-143/145-KLF4 circuit orchestrates the phenotypic switch of pulmonary artery smooth muscle cells.

Pulmonary hypertension (PH) is characterized by vascular remodeling predominantly driven by a phenotypic switching in pulmonary artery smooth muscle cells (PASMCs). However, the underlying mechanisms for this phenotypic alteration remain incompletely understood. Here, we identified that RNA methyltransferase METTL3 is significantly elevated in the lungs of hypoxic PH (HPH) mice and rats, as well as in the pulmonary arteries (PAs) of HPH rats. Targeted deletion of Mettl3 in smooth muscle cells exacerbated hemodynamic consequences of hypoxia-induced PH and accelerated pulmonary vascular remodeling in vivo. Additionally, the absence of METTL3 markedly induced phenotypic switching in PASMCs in vitro. Mechanistically, METTL3 depletion attenuated m6A modification and hindered the processing of pri-miR-143/145, leading to a downregulation of miR-143-3p and miR-145-5p. Inhibition of hnRNPA2B1, an m6A mediator involved in miRNA maturation, similarly resulted in a significant reduction of miR-143-3p and miR-145-5p. We demonstrated that miR-145-5p targets Krüppel-like factor 4 (KLF4) and miR-143-3p targets fascin actin-bundling protein 1 (FSCN1) in PASMCs. The decrease of miR-145-5p subsequently induced an upregulation of KLF4, which in turn suppressed miR-143/145 transcription, establishing a positive feedback circuit between KLF4 and miR-143/145. This regulatory circuit facilitates the persistent suppression of contractile marker genes, thereby sustaining PASMC phenotypic switch. Collectively, hypoxia-induced upregulation of METTL3, along with m6A mediated regulation of miR-143/145, might serve as a protective mechanism against phenotypic switch of PASMCs. Our results highlight a potential therapeutic strategy targeting m6A modified miR-143/145-KLF4 loop in the treatment of PH.

Nuclear transport of phosphorylated LanCL2 promotes invadopodia formation and tumor progression of glioblastoma by activating STAT3/Cortactin signaling.

INTRODUCTION: Our previous study showed that the abscisic acid receptor lanthionine synthetase C-like 2 (LanCL2) is a significant prognostic factor for overall survival in young glioblastoma patients. However, the role of LanCL2 in glioblastoma remains unclear yet. OBJECTIVES: This study aims to investigate the role of LanCL2 in regulating in-vitro cell invasion and in-vivo tumor progression of glioblastoma and its underlying mechanism. METHODS: Tyrosine 198 or 295 residue of LanCL2 was mutated using site-directed mutagenesis to block its phosphorylation. The role of LanCL2 in glioblastoma was investigated using transwell or 3D invasion assay, matrix degradation assay and intracranial xenograft model. RESULTS: This study showed that nuclear transport of LanCL2 was enhanced by overexpression of LanCL2 or its ligand abscisic acid in glioblastoma cells. Knockdown of LanCL2 suppressed migration, invasion and invadopodia formation of glioblastoma cells, whereas overexpression of wild-type LanCL2 enhanced them. Blocking of Tyr295 residue phosphorylation of LanCL2 impeded its nuclear transport, retarded glioblastoma cell motility and invadopodia formation, and deceased the phosphorylation of Cortactin and STAT3. c-Met was identified as the upstream tyrosine kinase of Tyr295 residue of LanCL2, and inhibition of c-Met markedly suppressed the nuclear transport of LanCL2. Moreover, overexpression of wild-type LanCL2 significantly promoted orthotopic tumor growth of glioblastoma in vivo and led to poor survival of mice with median survival time of 33.5 days, whereas Tyr295 mutation rescued it with median survival time of 49 days. CONCLUSION: Our findings suggested that Tyr295 phosphorylation is crucial to the activation and nuclear transport of LanCL2, as well as invadopodia formation and tumor progression of glioblastoma, providing the evidence of a novel signaling axis c-Met/LanCL2/STAT3/Cortactin and the first observation of the importance of Tyr295 phosphorylation to LanCL2.

Reconstruction of Concha-Type Microtia Using a Delayed Postauricular Skin Flap.

SUMMARY: Understanding how to remove and retain the relatively large residual auricle is important in concha-type microtia reconstruction. The authors present a method for concha-type microtia reconstruction using a delayed postauricular skin flap. A total of 40 patients with concha-type microtia who underwent ear reconstruction using a delayed postauricular skin flap were retrospectively examined. Reconstruction was performed in three stages. The first stage consisted of preparing a delayed postauricular skin flap and dealing with the residual auricle including removal of the upper residual auricular cartilage. In the second stage, an autogenous rib cartilage framework was placed and covered with a delayed postauricular skin flap, postauricular fascia flap, and autologous medium-thickness skin graft. The ear framework was carefully articulated and secured with the retained residual auricular cartilage to achieve a smooth junction between the two. The third stage involved modification of the reconstructed ear. Patients were followed up for 12 months after ear reconstruction. All reconstructed auricles had a good appearance, and there was a smooth connection between the reconstructed auricle and the residual ear, with similar color as well as a flat and thin scar. All patients were satisfied with the results. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

USP7 reduces the level of nuclear DICER, impairing DNA damage response and promoting cancer progression.

Endoribonuclease DICER is an RNase III enzyme that mainly processes microRNAs in the cytoplasm but also participates in nuclear functions such as chromatin remodelling, epigenetic modification and DNA damage repair. The expression of nuclear DICER is low in most human cancers, suggesting a tight regulation mechanism that is not well understood. Here, we found that ubiquitin carboxyl-terminal hydrolase 7 (USP7), a deubiquitinase, bounded to DICER and reduced its nuclear protein level by promoting its ubiquitination and degradation through MDM2, a newly identified E3 ubiquitin-protein ligase for DICER. This USP7-MDM2-DICER axis impaired histone γ-H2AX signalling and the recruitment of DNA damage response (DDR) factors, possibly by influencing the processing of small DDR noncoding RNAs. We also showed that this negative regulation of DICER by USP7 via MDM2 was relevant to human tumours using cellular and clinical data. Our findings revealed a new way to understand the role of DICER in malignant tumour development and may offer new insights into the diagnosis, treatment and prognosis of cancers.

USP2 promotes tumor immune evasion via deubiquitination and stabilization of PD-L1.

The abnormal upregulation of programmed death ligand-1 (PD-L1) on tumor cells impedes T-cell mediated cytotoxicity through PD-1 engagement, and further exploring the mechanisms regulation of PD-L1 in cancers may enhance the clinical efficacy of PD-L1 blockade. Here, using single-guide RNAs (sgRNAs) screening system, we identify ubiquitin-specific processing protease 2 (USP2) as a novel regulator of PD-L1 stabilization for tumor immune evasion. USP2 directly interacts with and increases PD-L1 abundance in colorectal and prostate cancer cells. Our results show that Thr288, Arg292 and Asp293 at USP2 control its binding to PD-L1 through deconjugating the K48-linked polyubiquitination at lysine 270 of PD-L1. Depletion of USP2 causes endoplasmic reticulum (ER)-associated degradation of PD-L1, thus attenuates PD-L1/PD-1 interaction and sensitizes cancer cells to T cell-mediated killing. Meanwhile, USP2 ablation-induced PD-L1 clearance enhances antitumor immunity in mice via increasing CD8+ T cells infiltration and reducing immunosuppressive infiltration of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), whereas PD-L1 overexpression reverses the tumor growth suppression by USP2 silencing. USP2-depletion combination with anti-PD-1 also exhibits a synergistic anti-tumor effect. Furthermore, analysis of clinical tissue samples indicates that USP2 is positively associated with PD-L1 expression in cancer. Collectively, our data reveal a crucial role of USP2 for controlling PD-L1 stabilization in tumor cells, and highlight USP2 as a potential therapeutic target for cancer immunotherapy.

Histopathological auxiliary system for brain tumour (HAS-Bt) based on weakly supervised learning using a WHO CNS5-style pipeline.

PURPOSE: Classification and grading of central nervous system (CNS) tumours play a critical role in the clinic. When WHO CNS5 simplifies the histopathology diagnosis and places greater emphasis on molecular pathology, artificial intelligence (AI) has been widely used to meet the increased need for an automatic histopathology scheme that could liberate pathologists from laborious work. This study was to explore the diagnosis scope and practicality of AI. METHODS: A one-stop Histopathology Auxiliary System for Brain tumours (HAS-Bt) is introduced based on a pipeline-structured multiple instance learning (pMIL) framework developed with 1,385,163 patches from 1038 hematoxylin and eosin (H&E) slides. The system provides a streamlined service including slide scanning, whole-slide image (WSI) analysis and information management. A logical algorithm is used when molecular profiles are available. RESULTS: The pMIL achieved an accuracy of 0.94 in a 9-type classification task on an independent dataset composed of 268 H&E slides. Three auxiliary functions are developed and a built-in decision tree with multiple molecular markers is used to automatically formed integrated diagnosis. The processing efficiency was 443.0 s per slide. CONCLUSION: HAS-Bt shows outstanding performance and provides a novel aid for the integrated neuropathological diagnostic workflow of brain tumours using CNS 5 pipeline.

Grading criteria for venous invasion in thoracic esophageal squamous cell carcinoma.

BACKGROUND: Venous invasion (VI) is an adverse prognostic indicator in esophageal squamous cell carcinoma. However, grading criteria for venous invasion in thoracic esophageal squamous cell carcinoma (ESCC) have not been established. METHODS: We enrolled 598 thoracic ESCC patients from 2005 to 2017. We detected the presence of venous invasion using the hematoxylin and eosin (H&E)-staining method and evaluated the VI grade on the basis of the number and maximal size of the involved veins. The degree of VI was classified as either 0, V1, V2, or V3, according to the combination of V-number and V-size. RESULTS: The 1-year, 3-year and 5-year disease-free survival rates were 79.7%, 64.7% and 61.2%, respectively. Multivariate analysis demonstrated that lymphatic invasion (HR: 1.457, 95% CI: 1.058-2.006, p = 0.021), T category (HR: 1.457, 95% CI: 1.058-2.006, p = 0.022), N category (HR: 1.535, 95% CI: 1.276-2.846, p < 0.001), stage (HR: 1.563, 95% CI: 1.235-1.976, p < 0.001) and the degree of venous invasion (HR: 1.526, 95% CI: 1.279-2.822, p < 0.001) were significant indicators of recurrence. The disease-free survival curves were distinguished especially well by the degree of venous invasion in stage III and IV patients. CONCLUSIONS: The present study explored an objective grading criterion for VI and proved the prognostic value of the degree of venous invasion in ESCC. The classification of venous invasion into 4 groups is useful for the differentiation of prognosis in ESCC patients. The prognostic significance of the degree of VI in advanced ESCC patients for recurrence may have to be considered.

Efficacy of pulsed dye laser combined with fractional CO2 laser in the treatment of pediatric burn scars.

OBJECTIVE: The present study aimed to investigate the efficacy and safety of pulsed dye laser (PDL) combined with fractional CO2 laser in the treatment of burn scars in pediatric patients. METHODS: The present retrospective study enrolled 60 pediatric patients with burn scars from July 2017 to June 2021. In the 4-month treatment period, all patients received PDL treatment every 1 month and received fractional CO2 laser treatment every 3 months. The Patient and Observer Scar Assessment Scale (POSAS) was used to evaluate the scar condition before the treatment as well as 6 months after the whole treatment. The satisfaction of the patient's parents was collected and recorded 6 months after the treatment. Complications were recorded during the treatment period and at follow-up visits. RESULTS: Among all patients, 38 (63.33%) cases were scald-induced scars and 22 (36.67%) cases were burn-induced scars. The mean diameter of the scar area was 107.53 ± 2.92 cm2 . For the measurement of the patient part of POSAS, all indices of pain, itching, color, stiffness, thickness, and irregularity, as well as the total scores were remarkably lower after 6 months of the treatment compared with the baseline (p < 0.05). For the observer part of POSAS, the indices of vascularization, pigmentation, thickness, relief, pliability, and surface area, as well as the total scores were markedly decreased after treatment (p < 0.05). The total satisfactory rate was 96.67% (58/60). No severe complications nor scar aggravation was observed. CONCLUSION: The combination of PDL and fractional CO2 laser showed good efficacy in the treatment of pediatric patients with burn scars with no severe complications and can be recommended in clinical application.

Raddeanin A Enhances Mitochondrial DNA-cGAS/STING Axis-Mediated Antitumor Immunity by Targeting Transactive Responsive DNA-Binding Protein 43.

Immune checkpoint therapies (ICT) have achieved unprecedented efficacy in multiple cancer treatments, but are still limited by low clinical response rates. Identification of immunogenic cell death (ICD)-inducing drugs that can induce tumor cell immunogenicity and reprogram the tumor microenvironment is an attractive approach to enhance antitumor immunity. In the present study, Raddeanin A (RA), an oleanane class triterpenoid saponin isolated from Anemone raddeana Regel, is uncovered as a potent ICD inducer through an ICD reporter assay combined with a T cell activation assay. RA significantly increases high-mobility group box 1 release in tumor cells and promotes dendritic cell (DC) maturation and CD8+ T cell activation for tumor control. Mechanistically, RA directly binds to transactive responsive DNA-binding protein 43 (TDP-43) and induces TDP-43 localization to mitochondria and mtDNA leakage, leading to cyclic GMP-AMP synthase/stimulator of interferon gene-dependent upregulation of nuclear factor κB and type I interferon signaling, thereby potentiating the DC-mediated antigen cross-presentation and T cell activation. Moreover, combining RA with anti-programmed death 1 antibody effectively enhances the efficacy of ICT in animals. These findings highlight the importance of TDP-43 in ICD drug-induced antitumor immunity and reveal a potential chemo-immunotherapeutic role of RA in enhancing the efficacy of cancer immunotherapy.

Apoptotic effects of phenols from the twigs and leaves of Garcinia nujiangensis.

In order to find potential agents for treating cancer disease in naturally occurring compounds, we conducted a systematic phytochemical investigation on the endemic species of Garcinia nujiangensis. Three new biphenyl derivatives (1-3) and one new polycyclic polyprenylated benzophenone (4), together with four known benzophenone analogues (5-8), have been isolated from the CH2Cl2 extract of the twigs and leaves of G. nujiangensis. Their structures were determined by detailed spectroscopic analyses and comparison with structurally related known analogues. Experimental and calculated ECD method was used to determine the absolute configuration of 1 and 4. Moreover, compounds 5-7 were isolated for the first time from this species. The cytotoxicities of the new compounds were evaluated using HL-60, HepG2, and A549 human cancer cell lines. Compound 4 showed more significant antiproliferative effects against HepG2 cells with an IC50 value of 11.38 ± 0.79 µM than that of three biphenyl derivatives. The morphological features of apoptosis were evaluated in 4-treated HepG2 cells. Compound 4 effectively prevented the cell cycle progression of HepG2 cells in G2 phase. Additionally, western blot analysis indicated that treatment of 4 on HepG2 cells led to decreased expression of anti-apoptotic Bcl-2 and pro-Caspase-3, and increased protein expression of both pro-apoptotic Bax and cleaved PARP with reference to ß-actin. Overall, our results suggested that the active polycyclic polyprenylated benzophenone derivatives in the twigs and leaves of G. nujiangensis can be used as a valuable source of bioactive compounds for the pharmaceutical industry.

Novel Small-Molecule PD-L1 Inhibitor Induces PD-L1 Internalization and Optimizes the Immune Microenvironment.

Blocking the PD-1/PD-L1 interaction has become an important strategy for tumor therapy, which has shown outstanding therapeutic effects in clinical settings. However, unsatisfactory response rates and immune-related adverse effects limit the use of anti-PD1/PD-L1 antibodies. Here, we report the discovery and identification of S4-1, an innovative small-molecule inhibitor of PD-L1. In vitro, S4-1 effectively altered the PD-L1/PD-1 interaction, induced PD-L1 dimerization and internalization, improved its localization to endoplasmic reticulum, and thus enhanced the cytotoxicity of peripheral blood mononuclear cells toward tumor cells. In vivo, S4-1 significantly inhibited tumor growth in both lung and colorectal cancer models, particularly in colorectal cancer, where it led to complete clearance of a portion of the tumor cells. Furthermore, S4-1 induced T-cell activation and inversed the inhibitory tumor microenvironment, consistent with the PD-L1/PD-1 pathway blockade. These data support the continued evaluation of S4-1 as an alternative ICB therapeutic strategy.

Novel phthalimides regulating PD-1/PD-L1 interaction as potential immunotherapy agents.

Programmed cell death 1(PD-1)/programmed cell death ligand 1(PD-L1) have emerged as one of the most promising immune checkpoint targets for cancer immunotherapy. Despite the inherent advantages of small-molecule inhibitors over antibodies, the discovery of small-molecule inhibitors has fallen behind that of antibody drugs. Based on docking studies between small molecule inhibitor and PD-L1 protein, changing the chemical linker of inhibitor from a flexible chain to an aromatic ring may improve its binding capacity to PD-L1 protein, which was not reported before. A series of novel phthalimide derivatives from structure-based rational design was synthesized. P39 was identified as the best inhibitor with promising activity, which not only inhibited PD-1/PD-L1 interaction (IC50 = 8.9 nmol/L), but also enhanced killing efficacy of immune cells on cancer cells. Co-crystal data demonstrated that P39 induced the dimerization of PD-L1 proteins, thereby blocking the binding of PD-1/PD-L1. Moreover, P39 exhibited a favorable safety profile with a LD50 > 5000 mg/kg and showed significant in vivo antitumor activity through promoting CD8+ T cell activation. All these data suggest that P39 acts as a promising small chemical inhibitor against the PD-1/PD-L1 axis and has the potential to improve the immunotherapy efficacy of T-cells.

Linear ubiquitination of PTEN impairs its function to promote prostate cancer progression.

PTEN is frequently mutated in human cancers, which leads to the excessive activation of PI3K/AKT signaling and thus promotes tumorigenesis and drug resistance. Met1-linked ubiquitination (M1-Ubi) is also involved in cancer progression, but the mechanism is poorly defined. Here we find that HOIP, one important component of linear ubiquitin chain assembly complex (LUBAC), promotes prostate cancer (PCa) progression by enhancing AKT signaling in a PTEN-dependent manner. Mechanistically, PTEN is modified by M1-Ubi at two sites K144 and K197, which significantly inhibits PTEN phosphatase activity and thus accelerates PCa progression. More importantly, we identify that the high-frequency mutants PTENR173H and PTENR173C in PCa patients showed the enhanced level of M1-Ubi, which impairs PTEN function in inhibition of AKT phosphorylation and cell growth. We also find that HOIP depletion sensitizes PCa cells to therapeutic agents BKM120 and Enzalutamide. Furthermore, the clinical data analyses confirm that HOIP is upregulated and positively correlated with AKT activation in PCa patient specimen, which may promote PCa progression and increase the risk of PCa biochemical relapse. Together, our study reveals a key role of PTEN M1-Ubi in regulation of AKT activation and PCa progression, which may propose a new strategy for PCa therapy.

Dual-source powered nanomotor with integrated functions for cancer photo-theranostics.

While the miniaturization and motility of artificial nanomotors made them popular tools for exploring novel and innovative biomedical cancer treatment strategies, the integration of multiple functions on the small motor bodies is key to achieve further progress but remains unresolved. Here, we propose a dual-source powered Janus nanomotor whose composition integrates multiple photo-theranostic functions such as surface-enhanced Raman scattering (SERS) sensing, fluorescence imaging/photoacoustic imaging (PAI), photodynamic therapy (PDT), and photothermal therapy (PTT). This nanomotor can be fabricated by sputtering a thin gold layer onto one side of mesoporous silica (mSiO2) combined with surface modification by photo-sensitizer, Raman reporter, and catalase. Upon illumination with 808 nm near-infrared light, the half-coated gold nanoshell serves as PAI/PTT agent, and by upconverting NIR to visible light, the pre-loaded photosensitizer can be excited by the upconverted light of UCNPs to convert the dissolved oxygen (O2) into reactive oxygen species for efficient PDT. Furthermore, ratiometric SERS signal can be captured to quantitatively detect the tumor marker, H2O2, in cellular microenvironments. The immobilized catalase as a nano-engine can catalyze endogenous H2O2 to O2. This function not only improves the hypoxic tumor microenvironment and therefore enhances PDT efficiency, but also provides a thrust force for deep penetration. As a proof of concept for the in vivo trial we performed cancer photo-theranostics where our nanomotors successfully treated a mouse breast tumor in a subcutaneous tumor model. The results are promising and encourage the use of an integrated nanomotor platform that could be further developed into a photo-theranostic agent for superficial cancer treatment.

Epicanthus correction with a modified asymmetric Z-plasty.

The study aimed to explore the clinical efficacy of the modified asymmetric Z-plasty with a central axis from the point near the edge of the skin fold of the medial canthus to the point of the innermost palpebral edge of medial canthus for epicanthus correction. A total of 130 followed-up patients who received modified asymmetric Z-plasty for epicanthus correction in Hunan Provincial People's Hospital from January 2019 to December 2019 were included. All patients were followed up with at 1, 3, and 6 months after surgery, and the scarring and surgical outcomes were assessed. The results showed the surgical wounds were healing well, and the sutures were removed at 7 days postoperatively in all patients. At 6 months postoperatively, epicanthus correction was successful in all patients, the lacrimal caruncle was moderately exposed, the incision was not red, and there were no obvious prominent scars. Slightly prominent and uneven scars below the edge of the lower eyelid were observed in 3 patients. Among these 3 patients, 1 patient received no further treatment, and the outcomes were considered acceptable; the outcomes were improved in the remaining 2 patients after a single session of fractional laser treatment, and none of these patients received further surgery. In conclusion, the modified asymmetric Z-plasty with a central axis from the point near the edge of the skin fold of the medial canthus to the point of the innermost palpebral edge of medial canthus is relatively simple and provides good surgical results for epicanthus correction.

Self-assembled iRGD-R7-LAHP-M nanoparticle induced sufficient singlet oxygen and enhanced tumor penetration immunological therapy.

The generation of singlet oxygen (1O2) using photodynamic therapy (PDT) is limited by the hypoxia of the tumor microenvironment and the depth of external light penetration because it depends on the precise cooperation between the photosensitizers, oxygen, and light. Herein, we report a self-sufficient 1O2 nanoreactor with enhanced penetration into deep tumors for cancer therapy. Linoleic acid hydroperoxide (LAHP) is coordinated with transition metal ions (Cu2+/Fe3+) to prepare linoleic acid hydroperoxide metal complex nanoparticles (LAHP-M NPs). iRGD combined with R7 decoration endows the nanoparticles with tumor targeting and penetration ability. We show that the polypeptide carries the nanoparticles into deep tumors, and thereafter the nanoparticles are disassembled into LAHP and catalytical metal ions to produce 1O2 based on the Russell mechanism under the stimulation of acidic pH. The elevated ROS induces necrotic cell death in vitro and in vivo, and further causes immunogenic cell death (ICD). This study demonstrates the effectiveness of exploiting biochemical reactions as a spatial-temporal strategy to overcome the current limitations of photodynamic therapy.

Exosomal MMP-1 transfers metastasis potential in triple-negative breast cancer through PAR1-mediated EMT.

PURPOSE: Triple-negative breast cancer (TNBC) is a subtype of breast cancer with high risk of distant metastasis, in which the intercellular communication between tumor cells also plays a role. Exosomes can be released by tumor cells and promote distant metastasis through intercellular communication or changes in tumor microenvironment, it is an optimized transportation facility for biologically active payloads. This was a hypothesis-generating research on role of exosomal payload in TNBC distant metastasis. METHODS: Exosomes isolated from supernatant of MDA-MB-231 and MDA-MB-231-HM (a highly pulmonary metastatic variant of parental MDA-MB-231 cells) were characterized. MMP-1 level was detected using mass spectrometry and western blot. Transwell assay, wound healing and CCK-8 assay were employed to explore the effect of exosomal MMP-1 on the metastatic capability of TNBC cells in vitro. Human breast cancer lung metastasis model in nude mice was established to observe the effect of exosomal MMP-1 in vivo. Tissue microarray and blood samples of TNBC patients were applied to analyze the relevance between MMP-1 with metastasis. RESULTS: MDA-MB-231-HM cells secrete exosomes enriched MMP-1, which can be taken up and enhance invasion and migration activities of TNBC cells, including MDA-MB-231, MDA-MB-468 and BT549. After ingesting exosomes enriched with MMP-1, cells secret more MMP-1, which may interact with membrane G protein receptor protease activated receptor 1 (PAR1), thereby initiating epithelial-mesenchymal transition (EMT) to enhance capability of migration and invasion. The lung colonization model shows that the expressions of MMP-1 and PAR1 in the metastases of the 231-HM-exo treated mice were both upregulated. Clinically, the enrichment of MMP-1 can be detected in exosomes extracted from serum of patients with metastasis at higher concentration than that in pre-operative patients. Moreover, in patients with multiple distant metastases, the level of MMP-1 in exosomes is also higher than that in patients with single lesion. CONCLUSION: MMP-1 from TNBC cells of high metastasis potential can promote the distant metastasis of transform those with low metastasis potential through PAR1-mediated EMT and is likely to be a potential molecular marker.

Antibacterial activities of plant-derived xanthones.

The increasing threat to global health posed by antibiotic resistance remains a serious concern. This troublesome scenario has steered a need for the discovery and evaluation of novel antibacterial agents. Natural products are the main sources of antimicrobials used in clinical practice, serving as a rich reservoir for the discovery of new antibiotics. Pharmaceutical phenolics especially xanthones widely exist in the plant kingdom, and are important plant metabolites. They possess versatile biological activities, including antiviral, antibacterial, neurotrophic, and anticancer. In the present study, we focus on the antibacterial activities of phytoxanthones and summarize their structures and sources, categories and drug-likeness evaluations, and antibacterial activities. A total of 226 different plant xanthones are identified through the NETs screening, and most of them are distributed in Clusiaceae family. These phytoxanthones are divided into four groups according to the intrinsic structural properties, including the most common simple xanthones and the majority of biprenylated ones. Moreover, their physicochemical parameters are calculated and the structure-activity relationships are discussed as well. These results indicate that the biprenylated xanthone derivatives may be promising antibacterial candidates and that the natural products of plants may be a poorly understood repository for the discovery of novel antibacterial agents.

Tubeimoside-1 induces TFEB-dependent lysosomal degradation of PD-L1 and promotes antitumor immunity by targeting mTOR.

Programmed cell death ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) cascade is an effective therapeutic target for immune checkpoint blockade (ICB) therapy. Targeting PD-L1/PD-1 axis by small-molecule drug is an attractive approach to enhance antitumor immunity. Using flow cytometry-based assay, we identify tubeimoside-1 (TBM-1) as a promising antitumor immune modulator that negatively regulates PD-L1 level. TBM-1 disrupts PD-1/PD-L1 interaction and enhances the cytotoxicity of T cells toward cancer cells through decreasing the abundance of PD-L1. Furthermore, TBM-1 exerts its antitumor effect in mice bearing Lewis lung carcinoma (LLC) and B16 melanoma tumor xenograft via activating tumor-infiltrating T-cell immunity. Mechanistically, TBM-1 triggers PD-L1 lysosomal degradation in a TFEB-dependent, autophagy-independent pathway. TBM-1 selectively binds to the mammalian target of rapamycin (mTOR) kinase and suppresses the activation of mTORC1, leading to the nuclear translocation of TFEB and lysosome biogenesis. Moreover, the combination of TBM-1 and anti-CTLA-4 effectively enhances antitumor T-cell immunity and reduces immunosuppressive infiltration of myeloid-derived suppressor cells (MDSCs) and regulatory T (Treg) cells. Our findings reveal a previously unrecognized antitumor mechanism of TBM-1 and represent an alternative ICB therapeutic strategy to enhance the efficacy of cancer immunotherapy.

Hypoxia regulates overall mRNA homeostasis by inducing Met1-linked linear ubiquitination of AGO2 in cancer cells.

Hypoxia is the most prominent feature in human solid tumors and induces activation of hypoxia-inducible factors and their downstream genes to promote cancer progression. However, whether and how hypoxia regulates overall mRNA homeostasis is unclear. Here we show that hypoxia inhibits global-mRNA decay in cancer cells. Mechanistically, hypoxia induces the interaction of AGO2 with LUBAC, the linear ubiquitin chain assembly complex, which co-localizes with miRNA-induced silencing complex and in turn catalyzes AGO2 occurring Met1-linked linear ubiquitination (M1-Ubi). A series of biochemical experiments reveal that M1-Ubi of AGO2 restrains miRNA-mediated gene silencing. Moreover, combination analyses of the AGO2-associated mRNA transcriptome by RIP-Seq and the mRNA transcriptome by RNA-Seq confirm that AGO2 M1-Ubi interferes miRNA-targeted mRNA recruiting to AGO2, and thereby facilitates accumulation of global mRNAs. By this mechanism, short-term hypoxia may protect overall mRNAs and enhances stress tolerance, whereas long-term hypoxia in tumor cells results in seriously changing the entire gene expression profile to drive cell malignant evolution.