Cancer SLC6A6-mediated taurine uptake transactivates immune checkpoint genes and induces exhaustion in CD8+ T cells.

Taurine is used to bolster immunity, but its effects on antitumor immunity are unclear. Here, we report that cancer-related taurine consumption causes T cell exhaustion and tumor progression. The taurine transporter SLC6A6 is correlated with aggressiveness and poor outcomes in multiple cancers. SLC6A6-mediated taurine uptake promotes the malignant behaviors of tumor cells but also increases the survival and effector function of CD8+ T cells. Tumor cells outcompete CD8+ T cells for taurine by overexpressing SLC6A6, which induces T cell death and malfunction, thereby fueling tumor progression. Mechanistically, taurine deficiency in CD8+ T cells increases ER stress, promoting ATF4 transcription in a PERK-JAK1-STAT3 signaling-dependent manner. Increased ATF4 transactivates multiple immune checkpoint genes and induces T cell exhaustion. In gastric cancer, we identify a chemotherapy-induced SP1-SLC6A6 regulatory axis. Our findings suggest that tumoral-SLC6A6-mediated taurine deficiency promotes immune evasion and that taurine supplementation reinvigorates exhausted CD8+ T cells and increases the efficacy of cancer therapies.

Regulation of the small GTPase Ran by miR-802 modulates proliferation and metastasis in colorectal cancer cells.

BACKGROUND: The small GTPase Ran is upregulated in multiple cancers and fundamental for cancer cell survival and progression, but its significance and molecular mechanisms in colorectal cancer (CRC) remain elusive. METHODS: Ran expression was detected in CRC cell lines and tumour tissues. In vitro and in vivo functional assays were performed to examine the effects of Ran on cell proliferation and metastasis. The pathways and effectors regulated by Ran were explored by an unbiased screening. Bioinformatics prediction and experimental validation were used to identify the miRNA regulator for Ran. RESULTS: Ran expression was frequently increased in metastatic CRC cells and tissues, especially in metastatic tissues. The upregulation of Ran correlated with poor CRC patient prognosis. Ran silencing reduced proliferation and metastasis of CRC cells both in vitro and in vivo. Ran regulated the expression of EGFR and activation of ERK and AKT signalling pathways. miR-802 was identified as an upstream regulator of Ran and miR-802 overexpression resulted in antiproliferative and antimetastatic activities. CONCLUSION: Our study demonstrates the oncogenic roles and underlying mechanisms of Ran in CRC and the novel miR-802/Ran/EGFR regulatory axis may provide potential biomarkers for the treatment of CRC.

LncNAP1L6 activates MMP pathway by stabilizing the m6A-modified NAP1L2 to promote malignant progression in prostate cancer.

Malignant progression such as bone metastasis, which is associated with pathologic fractures, pain and reduced survival frequently occurs in prostate cancer (PCa) patients at advanced stages. Accumulating evidence has supported that long non-coding RNAs (lncRNAs) participate in multiple biological processes. Nevertheless, the functions of most lncRNAs in PCa malignant progression remain largely unclear. Our current study is to elucidate the influence of lncRNA lncNAP1L6 on PCa malignant progression and uncover the possible regulatory mechanism. Firstly, RT-qPCR analysis was to detect lncNAP1L6 expression and suggested that lncNAP1L6 was markedly upregulated in PCa cells. Functional assays manifested that silencing of lncNAP1L6 hampered cell migration, invasion, and epithelial-mesenchymal transition (EMT) while overexpression of lncNAP1L6 exacerbated cell migration, invasion and EMT. In addition, mechanism assays were to determine the latent regulatory mechanism of lncNAP1L6. It turned out that METTL14/METTL3 complex mediated m6A methylation of NAP1L2 mRNA. Besides, lncNAP1L6 recruited HNRNPC to m6A-modified NAP1L2, leading to stabilization of NAP1L2 mRNA. Moreover, NAP1L6 interacted with YY1 to promote the transcription of MMP2 and MMP9 and activate MMP signaling pathway. In summary, lncNAP1L6 was identified as an oncogene in PCa, which revealed that lncNAP1L6 might be used as potential therapeutic target in PCa.

Comprehensive characterization of tumor microenvironment in colorectal cancer via molecular analysis.

Colorectal cancer (CRC) remains a challenging and deadly disease with high tumor microenvironment (TME) heterogeneity. Using an integrative multi-omics analysis and artificial intelligence-enabled spatial analysis of whole-slide images, we performed a comprehensive characterization of TME in colorectal cancer (CCCRC). CRC samples were classified into four CCCRC subtypes with distinct TME features, namely, C1 as the proliferative subtype with low immunogenicity; C2 as the immunosuppressed subtype with the terminally exhausted immune characteristics; C3 as the immune-excluded subtype with the distinct upregulation of stromal components and a lack of T cell infiltration in the tumor core; and C4 as the immunomodulatory subtype with the remarkable upregulation of anti-tumor immune components. The four CCCRC subtypes had distinct histopathologic and molecular characteristics, therapeutic efficacy, and prognosis. We found that the C1 subtype may be suitable for chemotherapy and cetuximab, the C2 subtype may benefit from a combination of chemotherapy and bevacizumab, the C3 subtype has increased sensitivity to the WNT pathway inhibitor WIKI4, and the C4 subtype is a potential candidate for immune checkpoint blockade treatment. Importantly, we established a simple gene classifier for accurate identification of each CCCRC subtype. Collectively our integrative analysis ultimately established a holistic framework to thoroughly dissect the TME of CRC, and the CCCRC classification system with high biological interpretability may contribute to biomarker discovery and future clinical trial design.

JAG1 is correlated to suppressive immune microenvironment and predicts immunotherapy resistance in lung adenocarcinoma.

Background: The current exploration of the tumor immune microenvironment is enthusiastic, but few studies explored the impact of angiogenesis on the immune microenvironment. Immunotherapy combined with anti-angiogenesis therapy has become one of the first-line treatment for lung adenocarcinoma. Our study aimed to explore the reasons for resistance of immunotherapy, and explore markers for immunotherapy combined with anti-angiogenesis therapy. Methods: First, by unsupervised clustering of 36 angiogenesis-related genes in lung adenocarcinoma patients from TCGA database, AGS1 and AGS2 groups were distinguished with significantly different clinical outcomes. Secondly, the immune microenvironment and metabolic characteristics were analyzed. Next, we used the GDSC and GEO database to analyze therapeutic responses. Then, through multivariate Cox regression, the hub gene: JAG1, significantly related to prognosis was selected, and further verified by multi-omics data. Finally, we validated that patient with high JAG1 expression had a low immune-infiltrating tumor microenvironment through single-cell transcriptomic data. Results: Compared with the AGS1 group, AGS2 showed an immune "cold" phenotype with lower lymphocyte infiltration, and was associated with worse prognoses. At the same time, the immunosuppressive TGF-ß response was significantly higher in AGS2. Furthermore, the glycolysis ability of the AGS2 was stronger than AGS1. The expression of JAG1 was significantly higher in the AGS2, and was significantly negatively correlated with the degree of immune infiltration, accompanying with higher glycolytic capacity. The above results indicate that patients with high expression of JAG1 may lead to immunosuppressive phenotype due to its strong glycolytic capacity, thus making immunotherapy resistance. Conclusion: Patients with high expression of JAG1 enhanced glycolytic capacity was likely to cause suppressed immune microenvironment. JAG1 may be a marker for resistance of immunotherapy. Combining anti-angiogenesis therapy could be considered to improve the prognosis of those patients.

Age-dependent genomic characteristics and their impact on immunotherapy in lung adenocarcinoma.

BACKGROUND: The incidence of lung cancer tends to be younger, and adenocarcinoma is the main histological type. Even patients with the same tumor type may have significant differences in clinical features, tumor microenvironment and genomic background at different ages. Immune checkpoint inhibitors (ICIs) have been shown to improve clinical outcomes in patients with lung adenocarcinoma (LUAD). However, differences in ICI efficacy between older and younger patients are unknown. Our study aimed to explore the relationship between age and immunotherapy in LUAD. METHODS: In our study, 1313 resected LUAD patients in our hospital were divided into young (age ≤ 50) and old groups (age > 50), and the clinical characteristic differences between them were analyzed. Of these, next-generation sequencing (NGS) was performed on the 311 cases. In addition, immune-related signatures of 508 LUAD patients were analyzed by TCGA RNA expression data. Then, we validated genomic and clinical information of 270 LUAD samples in the MSKCC cohort. RESULTS: ERBB2 and EGFR gene mutations were significantly different between the two groups, and the gene mutation number in the old group was significantly higher than that in the young group. In addition, immune-related signatures of LUAD patients were analyzed by TCGA RNA expression data, which indicated that the patients in the old group might have a better immune microenvironment. Then, we validated the MSKCC cohort and found that the TMB of the old group was significantly higher than that of the young group, and the OS of immunotherapy was longer in the old group. CONCLUSION: Our study was the first to analyze the differences in the genomic landscape and immune-related biomarkers between the young and old groups of LUAD patients and found that the old group had a better efficacy of immunotherapy, providing a reference for the study design and treatment of patients with LUAD.

The lncRNA MIR99AHG directs alternative splicing of SMARCA1 by PTBP1 to enable invadopodia formation in colorectal cancer cells.

Alternative splicing regulates gene expression and functional diversity and is often dysregulated in human cancers. Here, we discovered that the long noncoding RNA (lncRNA) MIR99AHG regulated alternative splicing to alter the activity of a chromatin remodeler and promote metastatic behaviors in colorectal cancer (CRC). MIR99AHG was abundant in invasive CRC cells and metastatic tumors from patients and promoted motility and invasion in cultured CRC cells. MIR99AHG bound to and stabilized the RNA splicing factor PTBP1, and this complex increased cassette exon inclusion in the mRNA encoding the chromatin remodeling gene SMARCA1. Specifically, MIR99AHG altered the nature of PTBP1 binding to the splice sites on intron 12 of SMARCA1 pre-mRNA, thereby triggering a splicing switch from skipping to including exon 13 to produce the long isoform, SMARCA1-L. SMARCA1, but not SMARCA1-L, suppressed invadopodia formation, cell migration, and invasion. Analysis of CRC samples revealed that the abundance of MIR99AHG transcript positively correlated with that of SMARCA1-L mRNA and PTBP1 protein and with poor prognosis in patients with CRC. Furthermore, TGF-ß1 secretion from cancer-associated fibroblasts increased MIR99AHG expression in CRC cells. Our findings identify an lncRNA that is induced by cues from the tumor microenvironment and that interacts with PTBP1 to regulate alternative splicing, potentially providing a therapeutic target and predictive biomarker for metastatic CRC.

Identification of Tumor Antigens and Immune Subtypes of Malignant Mesothelioma for mRNA Vaccine Development.

BACKGROUND: mRNA-based cancer vaccines have been considered a promising anticancer therapeutic approach against various cancers, yet their efficacy for malignant mesothelioma (MESO) is still not clear. The present study is designed to identify MESO antigens that have the potential for mRNA vaccine development, and to determine the immune subtypes for the selection of suitable patients. METHODS: A total of 87 MESO datasets were used for the retrieval of RNA sequencing and clinical data from The Cancer Genome Atlas (TCGA) databases. The possible antigens were identified by a survival and a genome analysis. The samples were divided into two immune subtypes by the application of a consensus clustering algorithm. The functional annotation was also carried out by using the DAVID program. Furthermore, the characterization of each immune subtype related to the immune microenvironment was integrated by an immunogenomic analysis. A protein-protein interaction network was established to categorize the hub genes. RESULTS: The five tumor antigens were identified in MESO. FAM134B, ALDH3A2, SAV1, and RORC were correlated with superior prognoses and the infiltration of antigen-presenting cells (APCs), while FN1 was associated with poor survival and the infiltration of APCs. Two immune subtypes were identified; TM2 exhibited significantly improved survival and was more likely to benefit from vaccination compared with TM1. TM1 was associated with a relatively quiet microenvironment, high tumor mutation burden, and enriched DNA damage repair pathways. The immune checkpoints and immunogenic cell death modulators were also differentially expressed between two subtypes. Finally, FN1 was identified to be the hub gene. CONCLUSIONS: FAM134B, ALDH3A2, SAV1, RORC, and FN1 are considered as possible and effective mRNA anti-MESO antigens for the development of an mRNA vaccine, and TM2 patients are the most suitable for vaccination.

A CGA/EGFR/GATA2 positive feedback circuit confers chemoresistance in gastric cancer.

De novo and acquired resistance are major impediments to the efficacy of conventional and targeted cancer therapy. In unselected gastric cancer (GC) patients with advanced disease, trials combining chemotherapy and an anti-EGFR monoclonal antibody have been largely unsuccessful. In an effort to identify biomarkers of resistance so as to better select patients for such trials, we screened the secretome of chemotherapy-treated human GC cell lines. We found that levels of CGA, the α-subunit of glycoprotein hormones, were markedly increased in the conditioned media of chemoresistant GC cells, and CGA immunoreactivity was enhanced in GC tissues that progressed on chemotherapy. CGA levels in plasma increased in GC patients who received chemotherapy, and this increase was correlated with reduced responsiveness to chemotherapy and poor survival. Mechanistically, secreted CGA was found to bind to EGFR and activate EGFR signaling, thereby conferring a survival advantage to GC cells. N-glycosylation of CGA at Asn52 and Asn78 is required for its stability, secretion, and interaction with EGFR. GATA2 was found to activate CGA transcription, whose increase, in turn, induced the expression and phosphorylation of GATA2 in an EGFR-dependent manner, forming a positive feedback circuit that was initiated by GATA2 autoregulation upon sublethal exposure to chemotherapy. Based on this circuit, combination strategies involving anti-EGFR therapies or targeting CGA with microRNAs (miR-708-3p and miR-761) restored chemotherapy sensitivity. These findings identify a clinically actionable CGA/EGFR/GATA2 circuit and highlight CGA as a predictive biomarker and therapeutic target in chemoresistant GC.

A Pan-Cancer Analysis of Predictive Methylation Signatures of Response to Cancer Immunotherapy.

Recently, tumor immunotherapy based on immune checkpoint inhibitors (ICI) has been introduced and widely adopted for various tumor types. Nevertheless, tumor immunotherapy has a few drawbacks, including significant uncertainty of outcome, the possibility of severe immune-related adverse events for patients receiving such treatments, and the lack of effective biomarkers to determine the ICI treatments' responsiveness. DNA methylation profiles were recently identified as an indicator of the tumor immune microenvironment. They serve as a potential hot spot for predicting responses to ICI treatment for their stability and convenience of measurement by liquid biopsy. We demonstrated the possibility of DNA methylation profiles as a predictor for responses to the ICI treatments at the pan-cancer level by analyzing DNA methylation profiles considered responsive and non-responsive to the treatments. An SVM model was built based on this differential analysis in the pan-cancer levels. The performance of the model was then assessed both at the pan-cancer level and in specific tumor types. It was also compared to the existing gene expression profile-based method. DNA methylation profiles were shown to be predictable for the responses to the ICI treatments in the TCGA cases in pan-cancer levels. The proposed SVM model was shown to have high performance in pan-cancer and specific cancer types. This performance was comparable to that of gene expression profile-based one. The combination of the two models had even higher performance, indicating the potential complementarity of the DNA methylation and gene expression profiles in the prediction of ICI treatment responses.

miR-125b Promotes Colorectal Cancer Migration and Invasion by Dual-Targeting CFTR and CGN.

Metastasis contributes to the poor prognosis of colorectal cancer, the causative factor of which is not fully understood. Previously, we found that miR-125b (Accession number: MIMAT0000423) contributed to cetuximab resistance in colorectal cancer (CRC). In this study, we identified a novel mechanism by which miR-125b enhances metastasis by targeting cystic fibrosis transmembrane conductance regulator (CFTR) and the tight junction-associated adaptor cingulin (CGN) in CRC. We found that miR-125b expression was upregulated in primary CRC tumors and metastatic sites compared with adjacent normal tissues. Overexpression of miR-125b in CRC cells enhanced migration capacity, while knockdown of miR-125b decreased migration and invasion. RNA-sequencing (RNA-seq) and dual-luciferase reporter assays identified CFTR and CGN as the target genes of miR-125b, and the inhibitory impact of CFTR and CGN on metastasis was further verified both in vitro and in vivo. Moreover, we found that miR-125b facilitated the epithelial-mesenchymal transition (EMT) process and the expression and secretion of urokinase plasminogen activator (uPA) by targeting CFTR and enhanced the Ras Homolog Family Member A (RhoA)/Rho Kinase (ROCK) pathway activity by targeting CGN. Together, these findings suggest miR-125b as a key functional molecule in CRC and a promising biomarker for the diagnosis and treatment of CRC.

KRAS Mutation-Responsive miR-139-5p inhibits Colorectal Cancer Progression and is repressed by Wnt Signaling.

Introduction: Colorectal cancer (CRC) frequently harbors KRAS mutations that result in chemoresistance and metastasis. MicroRNAs (miRNAs) are usually dysregulated and play important regulatory roles in tumor progression. However, the KRAS mutation-responsive miRNA profile in CRC remains uninvestigated. Methods: miR-139-5p was identified and evaluated by small RNA sequencing, qRT-PCR and in situ hybridization. The roles of miR-139-5p in CRC cells with and without KRAS mutation were determined by Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry and transwell assays in vitro and by tumorigenesis and metastasis assays in vivo. Microarrays followed by bioinformatic analyses, luciferase reporter assays and Western blotting were applied for mechanistic studies. Results: miR-139-5p was significantly downregulated in KRAS-mutated CRC cells and tissues compared with their wild-type counterparts. Low miR-139-5p expression was associated with aggressive phenotypes and poor prognosis in CRC patients. miR-139-5p overexpression inhibited CRC cell proliferation, migration and invasion in vitro, sensitized tumors to chemotherapy, and impaired tumor growth and metastasis in vivo. Transcriptomic profiling identified multiple modulators in the Ras (JUN and FOS) and Wnt (CTNNB1 and DVL1) signaling pathways and the epithelial-to-mesenchymal transition (EMT) process (ZEB1) as direct targets of miR-139-5p, and inverse correlations were confirmed in CRC clinical tissues. Aberrantly activated Wnt signaling in KRAS-mutant cells was demonstrated to transcriptionally repress miR-139-5p through TCF4, forming a miR-139-5p/Wnt signaling double-negative feedback loop. Conclusions: We identified miR-139-5p as a KRAS-responsive miRNA and demonstrated its involvement in CRC progression. KRAS mutation disrupted the miR-139-5p/Wnt signaling reciprocal negative feedback mechanism, which might cause miR-139-5p downregulation and derepression of oncogenic signaling pathways and EMT. These results reveal a transcriptional regulatory mode of KRAS-driven malignant transformation and highlight miR-139-5p as a novel regulator of crosstalk between the Ras and Wnt signaling pathways in CRC.

Synthesis, structure, and bonding of Eu3Bi(Sn,Bi)4. A rare inverse-Cr5B3-type structure with a new tin/bismuth network.

The ternary phase Eu3Bi(Sn1-xBix)4 ( approximately 0 < x < approximately 0.15) has been synthesized by solid-state methods at high temperature. The crystal structure of the limiting Eu3Bi(Sn3.39Bi0.61(3)) has been determined by single-crystal X-ray analysis to be isopointal with an inverse-Cr5B3-type structure [space group I4/mcm, Z = 4, a = 8.826(1) A, c = 12.564(3) A, and V = 978.6(3) A3]. The structure contains slabs of three-bonded Sn/Bi atoms as puckered eight- and four-membered rings interlinked at all vertices, and these are separated by planar layers of individual Eu and Bi atoms. In the normal (stuffed) Cr5B3-type analogue Eu5Sn3Hx, these two units are replaced by a more highly puckered network of Eu cations around isolated Sn atoms and planar layers of isolated Eu atoms and Sn dimers, respectively. Band structures of limiting models of the phase calculated by TB-LMTO-ASA methods show a metallic character and indicate that the mixed Sn/Bi occupancy in the slabs in this structure for x > 0 probably originates with the electronic advantages of the pseudogap that would occur at the electron count of the ideal Zintl phase Eu3Bi(Sn3Bi). The stability of a competing phase reduces this limit to Eu3Bi(Sn3.4Bi0.6).

M2Ba2Sn6 (m =yb, ca): metallic zintl phases with a novel tin chain substructure.

The compounds M2Ba2Sn6 (M = Yb, Ca) have been synthesized by solid-state reactions in welded Ta tubes at high temperature. Their structures were determined by single-crystal X-ray diffraction studies to be orthorhombic; space group Cmca (No. 64); Z = 8; a = 15.871(3), 15.912 (3) A; b = 9.387(2), 9.497(2) A; c = 17.212(3), 17.184(3) A; and V = 2564.3(9), 2597.0(9) A3, respectively. These contain infinite tin chains along constructed from butterflylike 3-bonded Sn tetramers interconnected by pairs of 2-bonded Sn. The chains are further interconnected into corrugated layers by somewhat longer Sn-Sn bonds along c. The compounds with the chains alone would be Zintl phases, but the interchain bonding makes them formally one-electron rich per formula unit. The electronic structures calculated by extended Hückel and TB-LMTO-ASA methods indicate that these compounds are metallic but with a deep pseudogap at the Fermi level. States that bind the extra electrons lie just below EF and involve important Yb(Ca)-Sn contributions. The origin of metallic Zintl phases is briefly discussed.

Hydrothermal synthesis and characterization of two organically templated cadmium borophosphates with novel structures.

Two organically templated cadmium borophosphates, (C(4)H(16)N(3))[CdClB(2)P(3)O(12)(OH)] (1) and (C(2)H(10)N(2))[CdB(2)P(3)O(12)(OH)] (2), were synthesized hydrothermally in the presence of structure-directing amines. Compound 1 has a complex layered structure (orthorhombic, Pbca (No. 61); a = 9.470(2), b = 12.307(3), c = 27.311(6) A; V = 3183 (1) A(3); Z = 8) with a 9MR channel system, while compound 2 (orthorhombic, Pbca (No. 61); a = 9.286(3), b = 12.459(3), c = 21.626(6) A; V = 2502(1) A(3); Z = 8) presents a 3-dimensional open framework structure of different types of intersecting channels. It is worth noting that both the Cl(-) anions and the organic templates play important and interesting roles in the formation of the structures.