SOX10 modulated SMARCA4 dysregulation alleviates DNA replication stress in cutaneous melanoma.

Cutaneous melanoma (CM) is the most fatal type of skin cancer with a high potency of metastasis, yet the treatment for metastatic melanoma remains limited. In this study, we are devoted to addressing the prognostic value and underlying mechanism of DNA damage repair-related genes in CM. We utilized integrated bioinformatic approaches and machine learning models to identify a cluster of convergently expressed DNA damage repair-related genes in melanoma. With multivariate Cox regression, SMARCA4 (also known as BRG1) was identified as an independent prognostic marker for melanoma patients. Yet the expression of SMARCA4 is not altered with the pathological staging or the metastasis condition. SMARCA4 is an essential ATPase subunit of the mammalian SWI/SNF complex. Mechanistically, we demonstrated that SMARCA4 could resolve DNA replication stress and guarantee the proliferation of melanoma cells. Furthermore, we predicted the binding of different transcription factors on the SMARCA4 promoter and unveiled the modulated expression of SMARCA4 by SOX10 in melanoma. Together, we performed integrated approaches to identify SMARCA4 as a promising prognostic marker for melanoma, which was transcriptionally regulated by SOX10 and promoted melanoma cell proliferation by ameliorating DNA replication stress.

Integrated multi-omics profiling to dissect the spatiotemporal evolution of metastatic hepatocellular carcinoma.

Comprehensive molecular analyses of metastatic hepatocellular carcinoma (HCC) are lacking. Here, we generate multi-omic profiling of 257 primary and 176 metastatic regions from 182 HCC patients. Primary tumors rich in hypoxia signatures facilitated polyclonal dissemination. Genomic divergence between primary and metastatic HCC is high, and early dissemination is prevalent. The remarkable neoantigen intratumor heterogeneity observed in metastases is associated with decreased T cell reactivity, resulting from disruptions to neoantigen presentation. We identify somatic copy number alterations as highly selected events driving metastasis. Subclones without Wnt mutations show a stronger selective advantage for metastasis than those with Wnt mutations and are characterized by a microenvironment rich in activated fibroblasts favoring a pro-metastatic phenotype. Finally, metastases without Wnt mutations exhibit higher enrichment of immunosuppressive B cells that mediate terminal exhaustion of CD8+ T cells via HLA-E:CD94-NKG2A checkpoint axis. Collectively, our results provide a multi-dimensional dissection of the complex evolutionary process of metastasis.

Liver-derived extracellular vesicles from patients with hepatitis B virus-related acute-on-chronic liver failure impair hepatic regeneration by inhibiting on FGFR2 signaling via miR-218-5p.

BACKGROUND: Impaired liver regeneration in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients is closely related to prognosis; however, the mechanisms are not yet defined. Liver-derived extracellular vesicles (EVs) may be involved in the dysregulation of liver regeneration. Clarifying the underlying mechanisms will improve the treatments for HBV-ACLF. METHODS: EVs were isolated by ultracentrifugation from liver tissues of HBV-ACLF patients (ACLF_EVs) after liver transplantation, and their function was investigated in acute liver injury (ALI) mice and AML12 cells. Differentially expressed miRNAs (DE-miRNAs) were screened by deep miRNA sequencing. The lipid nanoparticle (LNP) system was applied as a carrier for the targeted delivery of miRNA inhibitors to improve its effect on liver regeneration. RESULTS: ACLF_EVs inhibited hepatocyte proliferation and liver regeneration, with a critical role of miR-218-5p. Mechanistically, ACLF_EVs fused directly with target hepatocytes and transferred miR-218-5p into hepatocytes, acting by suppressing FGFR2 mRNA and inhibiting the activation of ERK1/2 signaling pathway. Reducing the level of miR-218-5p expression in the liver of ACLF mice partially restored liver regeneration ability. CONCLUSION: The current data reveal the mechanism underlying impaired liver regeneration in HBV-ACLF that promotes the discovery of new therapeutic approaches.

The negative effect of G1958A polymorphism on MTHFD1 protein stability and HCC growth.

PURPOSE: Methylenetetrahydrofolate dehydrogenase (MTHFD1), a key enzyme on the folate pathway, has been implicated in the tumor development of distinct types of cancers. The single nucleotide polymorphism (SNP) of 1958G > A mutation in the coding region of MTHFD1 (arginine 653 is mutated into glutamine) has been detected in a significant proportion of clinical samples of hepatocellular carcinoma (HCC). METHODS : Hepatoma cell lines, 97H and Hep3B were used. The expression of MTHFD1 and SNP mutation protein was determined by immunoblotting analysis. The protein ubiquitination of MTHFD1 was detected by immunoprecipitation analysis. The post-translational modification sites and interacting proteins of MTHFD1 in the presence of G1958A SNP were identified by mass spectrometry. Metabolic flux analysis was used to detect the synthesis of relevant metabolites sourced from serine isotope. RESULTS: The present study showed G1958A SNP of MTHFD1, encoding MTHFD1 R653Q, was associated with the attenuated protein stability caused by ubiquitination-mediated protein degradation. Mechanistically, MTHFD1 R653Q displayed an enhanced binding to the E3 ligase TRIM21, which was responsible for the augmented ubiquitination, and MTHFD1 K504 was identified to be the primary ubiquitination site. The subsequent metabolite analysis revealed MTHFD1 R653Q resulted in the repressed flux of serine-derived methyl group into metabolite precursors for purine synthesis, and the compromised purine synthesis was demonstrated to be responsible for the impeded growth capability in MTHFD1 R653Q-expressing cells. Moreover, the suppressive effect of MTHFD1 R653Q expression in tumorigenesis was verified by xenograft analysis, and the relationship between MTHFD1 G1958A SNP and its protein levels was revealed in clinical human liver cancer specimens. CONCLUSION: Our results uncovered an unidentified mechanism underlying of the impact of G1958A SNP on MTHFD1 protein stability and tumor metabolism in HCC. which provides a molecular basis for the according clinical management when considering MTHFD1 as a therapeutic target.

Aggregation-Induced Emission (AIE) and Magnetic Resonance Imaging Characteristics for Targeted and Image-Guided siRNA Therapy of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer and remains a global health challenge. Small interfering RNA (siRNA) is a promising therapeutic modality that blocks multiple disease-causing genes without impairing cell structures. However, siRNA therapeutics still have off-target proportion and lack effective quantitative analysis method in vivo. Thus, a novel theragnostic nanoparticle with dual-mode imaging is synthesized for targeted and image-guided siRNA therapy of HCC. Survivin siRNA is carried by Poly-ethylenimine (PEI) and interacted with T7-AIE/Gd NPs, which are self-assembled of DSPE-PEG-DTPA(Gd), DSPE-PEG-Mal, DSPE-PEG-PEI, and TPE. The resulting theragnostic nanoparticles exhibit lower toxicity and high therapeutic effect, and excellent T1-weighted magnetic resonance imaging (MRI) and aggregation-induced emission (AIE) imaging performance. Moreover, in vivo MRI and AIE imaging indicate that this kind of theragnostic nanoparticles rapidly accumulates in the tumor due to active targeting and enhanced permeability and retention (EPR) effects. Sur@T7-AIE-Gd suppresses HCC tumor growth by inducing autophagy and destabilizes DNA integrity in tumor cells. The results suggest that T7-AIE-Gd nanoparticles carrying Survivin siRNA with dual-mode imaging characteristics are promising for targeted and image-guided siRNA therapy of hepatocellular carcinoma.