Low level of ARID1A contributes to adaptive immune resistance and sensitizes triple-negative breast cancer to immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) shed new light on triple-negative breast cancer (TNBC), but only a minority of patients demonstrate response. Therefore, adaptive immune resistance (AIR) needs to be further defined to guide the development of ICI regimens. METHODS: Databases, including The Cancer Genome Atlas, Gene Ontology Resource, University of California Santa Cruz Genome Browser, and Pubmed, were used to screen epigenetic modulators, regulators for CD8+ T cells, and transcriptional regulators of programmed cell death-ligand 1 (PD-L1). Human peripheral blood mononuclear cell (Hu-PBMC) reconstruction mice were adopted for xenograft transplantation. Tumor specimens from a TNBC cohort and the clinical trial CTR20191353 were retrospectively analyzed. RNA-sequencing, Western blotting, qPCR and immunohistochemistry were used to assess gene expression. Coculture assays were performed to evaluate the regulation of TNBC cells on T cells. Chromatin immunoprecipitation and transposase-accessible chromatin sequencing were used to determine chromatin-binding and accessibility. RESULTS: The epigenetic modulator AT-rich interaction domain 1A (ARID1A) gene demonstrated the highest expression association with AIR relative to other epigenetic modulators in TNBC patients. Low ARID1A expression in TNBC, causing an immunosuppressive microenvironment, promoted AIR and inhibited CD8+ T cell infiltration and activity through upregulating PD-L1. However, ARID1A did not directly regulate PD-L1 expression. We found that ARID1A directly bound the promoter of nucleophosmin 1 (NPM1) and that low ARID1A expression increased NPM1 chromatin accessibility as well as gene expression, further activating PD-L1 transcription. In Hu-PBMC mice, atezolizumab demonstrated the potential to reverse ARID1A deficiency-induced AIR in TNBC by reducing tumor malignancy and activating anti-tumor immunity. In CTR20191353, ARID1A-low patients derived more benefit from pucotenlimab compared to ARID1A-high patients. CONCLUSIONS: In AIR epigenetics, low ARID1A expression in TNBC contributed to AIR via the ARID1A/NPM1/PD-L1 axis, leading to poor outcome but sensitivity to ICI treatment.

Plasma Extracellular Vesicle Long RNAs Have Potential as Biomarkers in Early Detection of Colorectal Cancer.

Background: Early detection of colorectal cancer (CRC) is crucial to the treatment and prognosis of patients. Traditional screening methods have disadvantages. Methods: 231 blood samples were collected from 86 CRC, 56 colorectal adenoma (CRA), and 89 healthy individuals, from which extracellular vesicle long RNAs (exLRs) were isolated and sequenced. An CRC diagnostic signature (d-signature) was established, and prognosis-associated cell components were evaluated. Results: The exLR d-signature for CRC was established based on 17 of the differentially expressed exLRs. The d-signature showed high diagnostic efficiency of CRC and control (CRA and healthy) samples with an area under the curve (AUC) of 0.938 in the training cohort, 0.943 in the validation cohort, and 0.947 in an independent cohort. The d-signature could effectively differentiate early-stage (stage I-II) CRC from healthy individuals (AUC 0.990), as well as differentiating CEA-negative CRC from healthy individuals (AUC 0.988). A CRA d-signature was also generated and could differentiate CRA from healthy individuals both in the training (AUC 0.993) and validation (AUC 0.978) cohorts. The enrichment of class-switched memory B-cells, B-cells, naive B-cells, and mast cells showed increasing trends between CRC, CRA, and healthy cohorts. Class-switched memory B-cells, mast cells, and basophils were positively associated with CRC prognosis while natural killer T-cells, naive B-cells, immature dendritic cells, and lymphatic endothelial cells were negatively associated with prognosis. Conclusions: Our study identified that the exLR d-signature could differentiate CRC from CRA and healthy individuals with high efficiency and exLR profiling also has potential in CRA screening and CRC prognosis prediction.

Isolation and characterization of exosomes for cancer research.

Exosomes are a subset of extracellular vesicles that carry specific combinations of proteins, nucleic acids, metabolites, and lipids. Mounting evidence suggests that exosomes participate in intercellular communication and act as important molecular vehicles in the regulation of numerous physiological and pathological processes, including cancer development. Exosomes are released by various cell types under both normal and pathological conditions, and they can be found in multiple bodily fluids. Moreover, exosomes carrying a wide variety of important macromolecules provide a window into altered cellular or tissue states. Their presence in biological fluids renders them an attractive, minimally invasive approach for liquid biopsies with potential biomarkers for cancer diagnosis, prediction, and surveillance. Due to their biocompatibility and low immunogenicity and cytotoxicity, exosomes have potential clinical applications in the development of innovative therapeutic approaches. Here, we summarize recent advances in various technologies for exosome isolation for cancer research. We outline the functions of exosomes in regulating tumor metastasis, drug resistance, and immune modulation in the context of cancer development. Finally, we discuss prospects and challenges for the clinical development of exosome-based liquid biopsies and therapeutics.

Discrete functional and mechanistic roles of chromodomain Y-like 2 (CDYL2) transcript variants in breast cancer growth and metastasis.

Rationale: Chromodomain Y-like 2 (CDYL2) is a member of the CDY gene family involved in spermatogenesis, but its role in human cancer has not been reported. Analyses of publicly available databases demonstrate that CDYL2 is abundantly expressed in breast tumors. However, whether CDYL2 is involved in breast cancer progression remains unknown. Methods: Quantitative real-time PCR and immunoblotting assays were used to determine the expression levels of CDYL2 transcript variants in breast cancer cell lines and primary breast tumors. The effect of CDYL2 transcript variants on the malignant phenotypes of breast cancer cells was examined through in vitro and in vivo assays. Immunofluorescent staining, RNA-seq, ATAC-seq, and ChIP-qPCR were used to investigate the underlying mechanisms behind the aforementioned observations. Results: Here we show that CDYL2 generated four transcript variants, named CDYL2a-CDYL2d. CDYL2a and CDYL2b were the predominant variants expressed in breast cancer cell lines and breast tumors and exerted strikingly discrete functions in breast cancer growth and metastasis. CDYL2a was upregulated in the majority of the breast cancer cell lines and tumors, and promoted breast cancer cell proliferation, colony formation in vitro, and tumorigenesis in xenografts. In contrast, CDYL2b was mainly expressed in luminal- and HER2-positive types of breast cancer cell lines and tumors, and suppressed the migratory, invasive, and metastatic potential of breast cancer cells in vitro and in vivo. Mechanistically, CDYL2a partially localized to SC35-positive nuclear speckles and promoted alternative splicing of a subset of target genes, including FIP1L1, NKTR, and ADD3 by exon skipping. Elimination of full-length FIP1L1, NKTR, and ADD3 rescued the impaired cell proliferation through CDYL2a depletion. In contrast, CDYL2b localized to heterochromatin and transcriptionally repressed several metastasis-promoting genes, including HPSE, HLA-F, and SELL. Restoration of HPSE, HLA-F, or SELL expression in CDYL2b-overexpressing cells attenuated the ability of CDYL2b to suppress breast cancer cell migration and invasion. Conclusions: Collectively, these findings establish an isoform-specific function of CDYL2 in breast cancer development and progression and highlight that pharmacological inhibition of the CDYL2a, but not the CDYL2b, isoform may be an effective strategy for breast cancer therapy.

Germline Missense Mutation of Deleted in Malignant Brain Tumor 1 (DMBT1) in Familial Mediastinal Neuroendocrine Cancer and in vitro Effects in Thyroid Cancer Cells.

BACKGROUND: Neuroendocrine tumors (NETs) rarely occur in the mediastinum and their etiology and pathogenesis are still unclear. OBJECTIVES: This study assessed inherited or de novo mutations in familial mediastinal NETs. METHOD: DNA samples from 4 patients were subjected to the whole-exome sequencing, and Sanger sequencing was used to identify Deleted in malignant brain tumor 1 (DMBT1) mutations in all 45 family members. RESULTS: All patients showed a germline DMBT1 mutation at 4971C. Sanger sequencing data showed that 4 NETs and 2 carriers in the first patient's family and 2 NETs and 4 carriers in the second patient's family, respectively, had this DMBT1 mutation. The in vitro data showed that the ectopic expression of DMBT1 reduced tumor cell viability and migration by arresting the G1/S phase of the cell cycle. CONCLUSIONS: We identified a germline missense mutation in DMBT1D1657E as a susceptibility gene for familial mediastinal NETs.

The endogenous retrovirus-derived long noncoding RNA TROJAN promotes triple-negative breast cancer progression via ZMYND8 degradation.

Human endogenous retroviruses (HERVs) play pivotal roles in the development of breast cancer. However, the detailed mechanisms of noncoding HERVs remain elusive. Here, our genome-wide transcriptome analysis of HERVs revealed that a primate long noncoding RNA, which we dubbed TROJAN, was highly expressed in human triple-negative breast cancer (TNBC). TROJAN promoted TNBC proliferation and invasion and indicated poor patient outcomes. We further confirmed that TROJAN could bind to ZMYND8, a metastasis-repressing factor, and increase its degradation through the ubiquitin-proteasome pathway by repelling ZNF592. TROJAN also epigenetically up-regulated metastasis-related genes in multiple cell lines. Correlations between TROJAN and ZMYND8 were subsequently confirmed in clinical samples. Furthermore, our study verified that antisense oligonucleotide therapy targeting TROJAN substantially suppressed TNBC progression in vivo. In conclusion, the long noncoding RNA TROJAN promotes TNBC progression and serves as a potential therapeutic target.

SNIP1 Recruits TET2 to Regulate c-MYC Target Genes and Cellular DNA Damage Response.

The TET2 DNA dioxygenase regulates gene expression by catalyzing demethylation of 5-methylcytosine, thus epigenetically modulating the genome. TET2 does not contain a sequence-specific DNA-binding domain, and how it is recruited to specific genomic sites is not fully understood. Here we carried out a mammalian two-hybrid screen and identified multiple transcriptional regulators potentially interacting with TET2. The SMAD nuclear interacting protein 1 (SNIP1) physically interacts with TET2 and bridges TET2 to bind several transcription factors, including c-MYC. SNIP1 recruits TET2 to the promoters of c-MYC target genes, including those involved in DNA damage response and cell viability. TET2 protects cells from DNA damage-induced apoptosis dependending on SNIP1. Our observations uncover a mechanism for targeting TET2 to specific promoters through a ternary interaction with a co-activator and many sequence-specific DNA-binding factors. This study also reveals a TET2-SNIP1-c-MYC pathway in mediating DNA damage response, thereby connecting epigenetic control to maintenance of genome stability.

[Effect of Low-concentration Ciprofloxacin on the Nitrification and Nitrifying Microorganisms of Biofilms in Biological Aerated Filter].

Effect of low-concentration ciprofloxacin (CIP) on nitrification and nitrifying microorganisms of biofilms was studied in biological aerated filters (BAF). Quantitative PCR (qPCR) was used to determine the abundance variance of four ciprofloxacin resistance genes (CIP-ARGs) during nitrification in biofilms. The correlations between the abundances of CIP-ARGs and nitrifying microorganisms were also discussed. The results showed that CIP had little influence on the ammonium oxidation process of biofilm microorganisms, whereas inhibition of the nitrite oxidation process was found. The quantitative results of ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) including Nitrobacter and Nitrospira indicated that the inhibition on the transformation of nitrite was resulted from the inhibition on Nitrobacter and Nitrospira. In addition, little influence of CIP on the relative abundance of aac and qepA in biofilms was found, but the influence on parC and oqxB was great. The abundance of Nitrotacter exhibited significant positive correlation with the abundance of parC. Similar significant correlation was also found between the abundances of Nitrospira and oqxB. It could be speculated that the genetic elements of different nitrifying microorganisms in biofilms possibly carried CIP-ARGs.

[Investigation of pollution characteristics of erythromycin resistance genes in a sewage treatment plant and the relevant selective factors].

Occurrence and distribution of twelve pharmaceutical and personal care products (PPCPs) were investigated in a sewage treatment plant in Shanghai using solid-phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS). Quantitative PCR (qPCR) was used to determine the distribution and removal of seven erythromycin resistance genes (ERY-ARGs). The results showed that five PPCPs including sulfamethoxazole, erythromycin, tetracycline, carbamazepine and triclosan were detected in the collected wastewater samples with concentrations in the ranges of 24.5- 38.7, 47.5-49.2, 43.1-85.4, 2.5-3.9 and 423.2-8 973.3 ng x L(-1), respectively. During the wastewater treatment process, a significant reduction of triclosan was observed, but the removal efficiencies for the other detected PPCPs were relatively low. Additionally, all target ERY-ARGs were detected in the wastewater samples ranging from 9.28 x 10(3) (ermA) to 1.83 x 10(8) (ereA) copies x L(-1) in raw influent. Though significant reductions (1.19 log-3.97 log) of ERY-ARGs were obtained, their concentrations found in the final effluent were still high. Moreover, the concentration of ERY-ARGs exhibited significant positive correlation with the concentration of erythromycin and triclosan (P < 0.05), respectively, elucidating that erythromycin played an important role in the occurrence and spread of ERY-ARGs, while triclosan may confer cross-selection for ERY-ARGs.

[Establishment and application of lentivirus luciferase reporter-mediated miRNA target gene screening system].

This study was aimed to establish a high-throughput luciferase reporter system, through which to screen and identify miRNAs directly targeting p21, and to explore the biological function and significance of these miRNAs. Molecular cloning technique was used to construct and identify two lentivirus-expressing vectors-pWPXL-Luc and pWPXL-Luc-P21-3'UTR, virus particles were collected after the pWPXL-Luc or pWPXL-Luc-P21-3'UTR vectors were co-transfected with the psPAX2 packaging plasmid and the envelope plasmid pDM2G into HEK-293T cells. Furthermore, two stable cell lines expressing luciferase singly or co-expressed luciferase and P21-3'UTR were established by transducing HEK-293 cells with recombinant lentivirus; the former was used as control in the following experiments. Finally luciferase activity of the latter stable cells was measured by using the luciferase reporter assay system. The results showed that high-titre recombinant lentivirus was produced and two stable cell lines were constructed, also to some certain, the luciferase activity was in direct proportion to the number of cells. In conclusion, the high-throughput luciferase reporter system is established successfully; using this system, the 28 miRNA that directly target P21 Cip1/Waf1 are screened experimentally.

[Effect of CRE-dependent RNA interference targeting Notch1 on proliferation of cervical cancer cell line HeLa].

BACKGROUND & OBJECTIVE: Notch signal transduction pathway mediates cell differentiation and proliferation. Its dysfunction is supposed to be involved in tumorigenesis and development. This study was to construct a course recombination enzyme(CRE)-dependent short hairpin RNA (shRNA) expression plasmid targeting Notch1, and investigate its effect on proliferation of cervical cancer cell line HeLa. METHODS: RNA interfering vectors pSico and pSicoR were used to construct CRE-dependent shRNA expression plasmids targeting GAPDH and Notch1; pBS185-CRE was used as an expression vector of CRE. HeLa cells were divided into 4 groups and transfected with pSico, pSico/CRE, pSicoR, and pSicoR/CRE, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were carried out to assess the efficiency of RNA interference (RNAi), and intracellular Notch signal level was tested by CBF-1 reporter plasmid. The proliferation of HeLa cells after CRE-dependent Notch1 RNAi was detected by MTS assay. RESULTS: After transfection of pSico (R)-GAPDH and pSico (R)-Notch1, CRE-dependent green fluorescent cells were detected; Notch1 expression was inhibited; intracellular Notch1 signal level was decreased; the proliferation of HeLa cells was suppressed. CONCLUSION: RNAi of Notch1 mediated by CRE-dependent shRNA expression plasmid can down-regulate intracellular Notch1 signal level and suppress the proliferation of HeLa cells.

Inhibition of Bcl-2 expression by a novel tumor-specific RNA interference system increases chemosensitivity to 5-fluorouracil in Hela cells.

AIM: RNA interference (RNAi) has been proposed as a potential treatment for cancer, but the lack of cellular targets limits its use in cancer gene therapy. No current technology has achieved direct tumor-specific gene silencing using RNAi. In the present study we attempt to develop a tumor-specific RNAi system using the human telomerase reverse transcriptase (hTERT) promoter; furthermore, we analyzed its inhibitive effect on Bcl-2 expression. METHODS: The vectors containing a small hairpin RNA (shRNA) to target exogenous reporters [firefly luciferase and enhanced green fluorescent protein (EGFP)] and endogenous gene (Bcl-2) were constructed. Luciferase expression was determined by dual luciferase assay. Reverse transcription-polymerase chain reaction (RT-PCR), fluorescence microscopy and fluorescence-activated cell sorting (FACS) were used to measure EGFP expression. Inhibition of Bcl-2 was evaluated by RT-PCR and Western blotting. Cell proliferation and viability were measured by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. FACS was used to analyze the cell cycle distribution profile. RESULTS: We showed that with the hTERT promoter directly driving shRNA transcription, expression of the exogenous reporters (LUC and EGFP) in tumor cells, but not normal cells, was specifically inhibited in vitro. The hTERT promoter-driven shRNA also depressed the expression of Bcl-2. Inhibition of Bcl-2 did not affect cell proliferation, but increased the chemosensitivity of HeLa cells to 5-fluorouracil. CONCLUSION: The present study describes an efficient RNAi system for gene silencing that is specific to tumor cells using the hTERT promoter. Suppression of Bcl-2 by using this system sensitized HeLa cells to 5-fluorouracil. This system may be useful for RNAi therapy.