Inhibition of PCSK9 prevents and alleviates cholesterol gallstones through PPARα-mediated CYP7A1 activation.

BACKGROUND & AIMS: Dysregulated cholesterol metabolism is the major factor responsible for cholesterol gallstones (CGS). Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a critical role in cholesterol homeostasis and its inhibitors secure approval for treating various cholesterol metabolic disorders such as hypercholesterolemia and cardiovascular diseases, but its role in CGS remains unclear. Our study aims to clarify mechanisms by which PCSK9 promotes CGS formation and explore the application of the PCSK9 inhibitor, alirocumab, in preventing and treating CGS. APPROACH & RESULTS: The expressions of PCSK9 were notably increased in CGS patients' serum, bile, and liver tissues compared to those without gallstones. Moreover, among CGS patients, hepatic PCSK9 was positively correlated with hepatic cholesterol and negatively correlated with hepatic bile acids (BAs), suggesting PCSK9 was involved in disrupted hepatic cholesterol metabolism related to CGS. Mechanistically, in vitro experiments demonstrated that inhibition of PCSK9 enhanced nuclear expression of PPARα by diminishing its lysosomal degradation and subsequently activated CYP7A1 transcription. Finally, inhibition of PCSK9 prevented CGS formation and dissolved the existing stones in CGS mice by elevating the conversion of cholesterol into BAs through PPARα-mediated CYP7A1 activation. Additionally, serum PCSK9 level may function as a prognostic signature to evaluate the therapeutic efficacy of PCSK9 inhibitors. CONCLUSIONS: Inhibition of PCSK9 exerts preventive and therapeutic effects on CGS by activating PPARα-mediated CYP7A1 expression and facilitating the conversion of cholesterol into BAs, which highlights the potential of PCSK9 inhibition as a promising candidate for preventing and treating CGS in clinical applications. IMPACT AND IMPLICATIONS: PCSK9 plays a pivotal role in cholesterol metabolism and its inhibitors are approved for clinical use in cardiovascular diseases. Our study observes inhibition of PCSK9 prevents and dissolves CGS by activating PPARα-mediated CYP7A1 expression and facilitating the conversion of cholesterol into BAs. Mechanistically, PCSK9 inhibition enhanced the nuclear expression of PPARα by diminishing its lysosomal degradation and subsequently activated CYP7A1 transcription. Our study sheds light on the new function and mechanism of PCSK9 in CGS, providing a novel preventive and therapeutic target with potential clinical applications.

A Novel TGF-ß-Related Signature for Predicting Prognosis, Tumor Microenvironment, and Therapeutic Response in Colorectal Cancer.

The transforming growth factor beta (TGF-ß) signaling plays a critical role in immune evasion and tumor progression. However, its modulatory influences on prognosis, tumor microenvironment (TME), and therapeutic efficacy remain unknown in colorectal cancer (CRC). We summarized TGF-ß-related genes and comprehensively estimated their expression pattern in 2142 CRC samples from 9 datasets. Two distinct cluster patterns were divided and biological characteristics of each pattern were further analyzed. Then, to quantify the TGF-ß cluster pattern of individual CRC patient, we generated the TGF-ß score (TGFBscore) model based on TGF-ß cluster pattern-relevant differentially expressed genes (DEGs). Subsequently, we conducted correlation analysis for TGFBscore and clinical prognosis, consensus molecular subtypes (CMSs), TME characteristics, liver metastasis, drug response, and immunotherapeutic efficacy in CRC. We illustrated transcriptional and genetic alterations of TGF-ß-relevant genes, which were closely linked with carcinogenic pathways. We identified two different TGF-ß cluster patterns, characterized by a high and a low TGFBscore. The TGFBscore-high group was significantly linked with worse patient survival, epithelial-mesenchymal transition (EMT) activation, liver metastasis tendency, and the infiltration of immunosuppressive cells (regulatory T cells [Tregs], M2 macrophages, cancer-associated fibroblasts [CAFs], and myeloid-derived suppressor cells [MDSCs]), while the TGFBscore-low group was linked with a survival advantage, epithelial phenotype, early CRC staging, and the infiltration of immune-activated cells (B cell, CD4 T cell, natural killer T [NKT] cell, and T helper 1 [Th1] cell). In terms of predicting drug response, TGFBscore negatively correlated (sensitive to TGFBscore-high group) with drugs targeting PI3K/mTOR, JNK and p38, RTK signaling pathways, and positively correlated (sensitive to TGFBscore-low group) with drugs targeting EGFR signaling pathway. Also, TGFBscore could predict the efficacy of different anti-tumor therapies. TGFBscore-low patients might benefit more from anti-PDL1 immunotherapy, adjuvant chemotherapy (ACT), and ERBB targeted therapy, whereas TGFBscore-high patients might benefit more from antiangiogenic targeted therapy. Our study constructed a novel TGF-ß scoring model that could predict prognosis, liver metastasis tendency, and TME characteristics for CRC patients. More importantly, this work emphasizes the potential clinical utility of TGFBscore in evaluating the efficacy of chemotherapy, targeted therapy, and immunotherapy, guiding individualized precision treatment in CRC.

Extracellular vesicle-carried GTF2I from mesenchymal stem cells promotes the expression of tumor-suppressive FAT1 and inhibits stemness maintenance in thyroid carcinoma.

Through bioinformatics predictions, we identified that GTF2I and FAT1 were downregulated in thyroid carcinoma (TC). Further, Pearson's correlation coefficient revealed a positive correlation between GTF2I expression and FAT1 expression. Therefore, we selected them for this present study, where the effects of bone marrow mesenchymal stem cell-derived EVs (BMSDs-EVs) enriched with GTF2I were evaluated on the epithelial-to-mesenchymal transition (EMT) and stemness maintenance in TC. The under-expression of GTF2I and FAT1 was validated in TC cell lines. Ectopically expressed GTF2I and FAT1 were found to augment malignant phenotypes of TC cells, EMT, and stemness maintenance. Mechanistic studies revealed that GTF2I bound to the promoter region of FAT1 and consequently upregulated its expression. MSC-EVs could shuttle GTF2I into TPC-1 cells, where GTF2I inhibited TC malignant phenotypes, EMT, and stemness maintenance by increasing the expression of FAT1 and facilitating the FAT1-mediated CDK4/FOXM1 downregulation. In vivo experiments confirmed that silencing of GTF2I accelerated tumor growth in nude mice. Taken together, our work suggests that GTF2I transferred by MSC-EVs confer antioncogenic effects through the FAT1/CDK4/FOXM1 axis and may be used as a promising biomarker for TC treatment.

Localization and density of tertiary lymphoid structures associate with molecular subtype and clinical outcome in colorectal cancer liver metastases.

BACKGROUND: Tertiary lymphoid structures (TLSs) have been proposed to assess the prognosis of patients with cancer. Here, we investigated the prognostic value and relevant mechanisms of TLSs in colorectal cancer liver metastases (CRCLM). METHODS: 603 patients with CRCLM treated by surgical resection from three cancer centers were included. The TLSs were categorized according to their anatomic subregions and quantified, and a TLS scoring system was established for intratumor region (T score) and peritumor region (P score). Differences in relapse-free survival (RFS) and overall survival (OS) between groups were determined. Multiplex immunohistochemical staining (mIHC) was used to determine the cellular composition of TLSs in 40 CRCLM patients. RESULTS: T score positively correlated with superior prognosis, while P score negatively associated with poor survival (all p<0.05). Meanwhile, T score was positively associated with specific mutation subtype of KRAS. Furthermore, TLSs enrichment gene expression was significantly associated with survival and transcriptomic subtypes of CRCLM. Subsequently, mIHC showed that the densities of Treg cells, M2 macrophages and Tfh cells were significantly higher in intratumor TLSs than in peritumor TLSs (p=0.029, p=0.047 and p=0.041, respectively), and the frequencies of Treg cells and M2 macrophages were positively correlated with P score, while the frequencies of Tfh cells were positively associated with T scores in intratumor TLSs (all p<0.05). Next, based on the distribution and abundance of TLSs, an Immune Score combining T score and P score was established which categorized CRCLM patients into four immune classes with different prognosis (all p<0.05). Among them, patients with higher immune class have more favorable prognoses. The C-index of Immune Class for RFS and OS was higher than Clinical Risk Score statistically. These results were also confirmed by the other two validation cohorts. CONCLUSIONS: The distribution and abundance of TLSs is significantly associated with RFS and OS of CRCLM patients, and a novel immune class was proposed for predicting the prognosis of CRCLM patients.

The prognostic significance of clinicopathological characteristics in early-onset versus late-onset colorectal cancer liver metastases.

PURPOSE: This study aimed to explore the prognostic significance of clinicopathological characteristics in early-onset versus late-onset colorectal liver metastases (CRLM). METHODS: The data of CRLM patients who underwent hepatectomy from September 2010 to September 2020 were retrospectively analyzed. According to the age of primary cancer diagnosis, patients were divided into early-onset CRLM (EOCRLM) and late-onset CRLM (LOCRLM) groups. Clinicopathological parameters were compared between the two groups. Cox regression model and Kaplan-Meier method were used to analyze the effect of clinicopathological parameters on overall survival (OS) and recurrence-free survival (RFS). RESULTS: In total, 431 CRLM patients were identified, 130 with EOCRLM and 301 with LOCRLM. Compared with LOCRLM patients, EOCRLM patients had lower American Society of Anesthesia (ASA) grade and longer operation time (204 vs. 179 min). More aggressive features were presented in EOCRLM patients including synchronous liver metastases (76.9% vs. 61.1%) and bilobar involvement (43.8% vs. 33.2%). No significant difference in OS or RFS was found between the two groups. Multivariate analysis of EOCRLM group showed that preoperative CA19-9 level and RAS/BRAF status were predictive of OS, while bilobar involvement and preoperative CEA level were associated with RFS. In LOCRLM group, the number of CRLM, preoperative CA19-9 level, and BRAF status were associated with OS, while the number of CRLM was associated with RFS. CONCLUSIONS: The preoperative CA19-9 level, RAS/BRAF status, bilobar involvement, and preoperative CEA level were predictive of EOCRLM patient prognosis, while the number of CRLM, preoperative CA19-9 level, and BRAF status were predictive of LOCRLM patient prognosis.

Dual immune checkpoint inhibitors or combined with anti-VEGF agents in advanced, unresectable hepatocellular carcinoma.

BACKGROUND: Immune checkpoint inhibitor monotherapy did not show superiority of survival over standard therapy in advanced hepatocellular carcinoma. The combination immunotherapy including dual immune checkpoint inhibitors or combined with anti-VEGF agents have become a trend, but not fully evaluated. This study aimed to evaluate and compare distinct combination immunotherapy on efficacy in advanced hepatocellular carcinoma. METHODS: PubMed, Embase, Web of Science and Cochrane databases were systematically searched from inception to January 31, 2022. The primary endpoints were overall objective response rate (ORR), disease control rate (DCR), six-month progression-free survival rate (PFSR6m) and one-year overall survival rate (OSR1y). RESULTS: 11 studies with 16 independent cohorts and 3342 patients were included in the meta-analysis. Compared with first-line sorafenib, combination immunotherapy resulted in a significant improvement in ORR (RR, 2.74; 95%CI, 1.55-4.85; p = 0.0006), PFS (HR, 0.57; 95%CI, 0.49-0.65; p<0.0001) and OS (HR, 0.65; 95%CI, 0.52-0.82; p = 0.0002). Based on RECIST 1.1, the pooled ORR, PFSR6m and OSR1y for combination immunotherapy were 24.6% (95%CI: 20.3%-29.6%), 42.0% (95%CI: 34.2%-50.3%) and 61.8% (95%CI: 57.7%-65.7%), respectively. In distinct combination regimens, PD-1/L1 inhibitors plus anti-VEGF agents showed a significant superiority of clinical benefit than PD-1/L1 inhibitors plus CTLA-4 inhibitors (ORR: 25.2% vs 23.4%, p = 0.033; PFSR6m: 47.4% vs 23.2%, p<0.001; OSR1y: 65.1% vs 55.0%, p = 0.001). CONCLUSIONS: This study was the first meta-analysis to demonstrate the better survival benefit and tolerable toxicity of combination immunotherapy than standard therapy in advanced hepatocellular carcinoma. Compared with PD-1/L1 inhibitors plus CTLA-4 inhibitors, the regimens of PD-1/L1 inhibitors plus anti-VEGF agents may be associated with a significantly better clinical benefit. The difference in long-term survival and response population between two distinct combination regimens required further exploration.

27-Hydroxycholesterol promotes metastasis by SULT2A1-dependent alteration in hepatocellular carcinoma.

Oxysterol metabolism plays an important role in the initiation and development of various tumors. However, little is known that the metabolic alternation can promote the metastasis of hepatocellular carcinoma (HCC). In this study, we identify the sulfotransferase family 2A member 1 (SULT2A1) to 27-hydroxycholesterol (27-OHC) metabolic axis as playing a critical role in HCC metastasis. The level of 27-OHC closely corresponded with HCC metastasis instead of proliferation in vitro and in vivo. Also, the expression of SULT2A1 is extremely downregulated in human HCC tissues and is correlated with poor prognosis and tumor metastasis. Gain- and loss-of-function studies reveal that SULT2A1 suppresses the metastasis of HCC by regulating the level of 27-OHC. Further mechanistic studies indicated that SULT2A1-dependent alternation of 27-OHC activates the nuclear factor-κB signaling pathway and promotes HCC metastasis by enhancing Twist1 expression and epithelial-mesenchymal transition. In conclusion, our findings indicate the relationship between the metabolism of 27-OHC and the metastasis of HCC. Moreover, SULT2A1 could act as a potential prognostic biomarker and a therapeutic target for preventing HCC metastasis.

m6A target microRNAs in serum for cancer detection.

Recent studies have revealed the significant dysregulation of m6A level in peripheral blood in several cancer types and its value in diagnosis. Nonetheless, a biomarker for accurate screening of multiple cancer types has not been established based on the perspective of m6A modification. In this study, we aimed to develop a serum diagnostic signature based on the m6A target miRNAs for the mass detection of cancer. A total of 14965 serum samples with 12 cancer types were included. Based on training cohort (n=7299), we developed the m6A-miRNAs signature using a support vector machine algorithm for cancer detection. The m6A-miRNAs signature showed high accuracy, and its area under the curve (AUC) in the training, internal validation and external validation cohort reached 0.979 (95%CI 0.976 - 0.982), 0.976 (95%CI 0.973 - 0.979) and 0.936 (95%CI 0.922 - 0.951), respectively. In the performance of distinguishing cancer types, the m6A-miRNAs signature showed superior sensitivity in each cancer type and presented a satisfactory AUC in identifying lung cancer, gastric cancer and hepatocellular carcinoma. Additionally, the diagnostic performance of m6A-miRNAs was not interfered by the gender, age and benign disease. In short, this study revealed the value of serum circulating m6A miRNAs in cancer detection and provided a new direction and strategy for the development of novel biomarkers with high accuracy, low cost and less invasiveness for mass cancer screening, such as RNA modification.

ß-elemene affects angiogenesis of infantile hemangioma by regulating angiotensin-converting enzyme 2 and hypoxia-inducible factor-1 alpha.

Infantile hemangioma (IH) is the most common benign vascular tumor resulting from the hyper-proliferation of vascular endothelial cells. In treatment of various tumors including IH, ß-elemene, a compound extracted from Rhizoma zedoariae, has been reported to have anti-tumor effect. However, the underlying mechanisms of ß-elemene in hemangioma have remained uninvestigated. In this presented study, functional analysis showed that low concentrations of ß-elemene promoted the proliferation, migration and tube formation of human hemangioma endothelial cells (HemECs), while high concentrations of ß-elemene produced inhibitory effects. Further, we also found that angiotensin-converting enzyme 2 (ACE2) expression was down-regulated at both mRNA and protein levels, while hypoxia-inducible factor-1 alpha (HIF-1-α) was up-regulated in infantile hemangiomas tissues and HemECs at both mRNA and protein levels. This result suggested that ACE2 and HIF-1-α play roles in IH. ACE2 expression was down-regulated with the treatment of ß-elemene at different dosage point. Interestingly, the expression of Vascular endothelial growth factor-A (VEGFA) increased with treatment of low concentrations of ß-elemene in HemECs, in contrary, the expression of VEGFA expression decreased with treatment of high concentrations of ß-elemene. Moreover, if the concentration of ß-elemene reached 40 µg/ml or higher, the expression of HIF-1-α decreased. Taken together, our data indicated that the different effects of ß-elemene on the proliferation, migration and angiogenesis of hemangioma at different concentrations: The ACE2 signaling pathway dominates with treatment of low concentrations of ß-elemene, stimulating the expression of downstream VEGFA to promote the angiogenesis of hemangioma; under the condition of high concentrations of ß-elemene, the HIF-1-α signaling pathway inhibits the expression of VEGFA and further inhibits the angiogenesis of hemangioma.

Multi-omics analysis reveals the functional transcription and potential translation of enhancers.

Enhancer can transcribe RNAs, however, most of them were neglected in traditional RNA-seq analysis workflow. Here, we developed a Pipeline for Enhancer Transcription (PET, http://fun-science.club/PET) for quantifying enhancer RNAs (eRNAs) from RNA-seq. By applying this pipeline on lung cancer samples and cell lines, we showed that the transcribed enhancers are enriched with histone marks and transcription factor motifs (JUNB, Hand1-Tcf3 and GATA4). By training a machine learning model, we demonstrate that enhancers can predict prognosis better than their nearby genes. Integrating the Hi-C, ChIP-seq and RNA-seq data, we observe that transcribed enhancers associate with cancer hallmarks or oncogenes, among which LcsMYC-1 (Lung cancer-specific MYC eRNA-1) potentially supports MYC expression. Surprisingly, a significant proportion of transcribed enhancers contain small protein-coding open reading frames (sORFs) and can be translated into microproteins. Our study provides a computational method for eRNA quantification and deepens our understandings of the DNA, RNA and protein nature of enhancers.

Super-enhancers modulate interleukin-6 expression and function in cancers.

BACKGROUND: It is widely accepted that inflammatory cytokine, interleukin 6 (IL-6), was not only elevated in cancer but also important in carcinogenesis. But how did IL-6 be produced in tumor microenvironment remains to be addressed. METHODS: Both bioinformatics tools and quantitative real time polymerase chain reaction (RT-PCR) were used to examine the expression of IL-6 in cancer cells. To map super-enhancers of IL-6, sgRNAs were constructed. Stable knockout cells were established and subsequently used for cell proliferation and colony formation assay. The correlation between mapped super-enhancers and IL-6 expression was studied by ATAC-seq analysis. RESULTS: The expression of IL-6 was high in multiple cancers, including pancreatic cancer (PAAD). The elevated expression of IL-6 in PAAD was further confirmed by transcriptional data and in a panel of pancreatic cancer cell lines (one immortal HPDE6-C7 cell line and four PDAC cell lines: BxPC-3, PANC-1, AsPC-1 and CFPAC-1). When treated with JQ-1 and I-BET-762, two inhibitors of super-enhancers, the expression of IL-6 in multiple cancer cells including CFPAC-1, HeLa and SUM-159 cells was significantly reduced. By analyzing the H3K27Ac profiling, BRD4 binding, Med1 binding and DNA conservation in CFPAC-1, HeLa and SUM-159 cells, we identified a potential super-enhancer (IL6-SE) that might be important for IL-6 expression in cancer. The super-enhancer (IL6-SE) can be further divided into two elements (IL6-SEa and IL6-SEb). Genetic deletion of IL6-SEa in cancer cells greatly reduces the expression of IL-6. IL6-SEa deficient cells also showed low proliferation and colony formation ability. In patients, the epigenetic activation (ATAC signal) of IL6-SEa is correlated with the expression of IL-6. CONCLUSIONS: In summary, we not only provide convincing experimental evidence to demonstrate that IL-6 expression in cancer is dependent on super-enhancers but also identified IL6-SEa as a critical DNA regulatory element. Our findings provide new insights to understand the epigenetic regulation of IL-6 expression in cancers.

A Tumor-Specific Super-Enhancer Drives Immune Evasion by Guiding Synchronous Expression of PD-L1 and PD-L2.

PD-L1 and PD-L2 are important targets for immune checkpoint blockade, but how tumor cells achieve their expression remains to be addressed. Here, we find that PD-L1 and PD-L2 are co-expressed in cancer cell lines and tissues across different cancer types. In breast cancer, MDA-MB-231 and SUM-159 cells show high expression of both PD-L1 and PD-L2. The expression of both PD-L1 and PD-L2 is greatly reduced upon treatment of inhibitors of super-enhancers. Bioinformatic analysis identifies a potential super-enhancer (PD-L1L2-SE) that is located between the CD274 and CD273 genes. Genetic deletion of PD-L1L2-SE profoundly reduces the expression of PD-L1 and PD-L2. PD-L1L2-SE-deficient cancer cells fail to generate immune evasion and are sensitive to T cell-mediated killing. Notably, epigenetic activation of such a region (PD-L1L2-SE) is correlated with PD-L1 and PD-L2. Taken together, we identify a super-enhancer (PD-L1L2-SE) that is responsible for the overexpression of PD-L1 and PD-L2 as well as immune evasion in cancer.

Pan-Cancer Analysis Reveals Disrupted Circadian Clock Associates With T Cell Exhaustion.

Although dysfunctional circadian clock has emerged as a hallmark of cancer, fundamental gaps remain in our understanding of the underlying mechanisms involved. Here, we systematically analyze the core genes of the circadian clock (CLOCK, ARNTL, ARNTL2, NPAS2, NR1D1, NR1D2, CRY1, CRY2, RORA, RORB, RORC, PER1, PER2, and PER3) across a broad range of cancers. To our surprise, core negative regulators (PER1, PER2, PER3, CRY1, and CRY2) are consistently downregulated, while core positive regulators show minimal alterations, indicating disrupted circadian clock in cancers. Such downregulation originates from copy number variations where heterozygous deletion predominates. The disrupted circadian clock is significantly associated with patient outcome. Further pathway enrichment analysis suggests that the circadian clock widely impacts 45 pathways such as the Ras signaling pathway and T cell receptor signaling pathway. By using state-of-the-art immune cell deconvolution and pathway quantification, we demonstrate that abnormal circadian clock contributes to T cell exhaustion and global upregulation of immune inhibitory molecules such as PD-L1 and CTLA-4. In summary, the rhythm of the circadian clock is disrupted in cancers. Abnormal circadian clock linked with immune evasion may serve as a potential hallmark of cancer.