A membrane-associated MHC-I inhibitory axis for cancer immune evasion.

Immune-checkpoint blockade has revolutionized cancer treatment, but some cancers, such as acute myeloid leukemia (AML), do not respond or develop resistance. A potential mode of resistance is immune evasion of T cell immunity involving aberrant major histocompatibility complex class I (MHC-I) antigen presentation (AP). To map such mechanisms of resistance, we identified key MHC-I regulators using specific peptide-MHC-I-guided CRISPR-Cas9 screens in AML. The top-ranked negative regulators were surface protein sushi domain containing 6 (SUSD6), transmembrane protein 127 (TMEM127), and the E3 ubiquitin ligase WWP2. SUSD6 is abundantly expressed in AML and multiple solid cancers, and its ablation enhanced MHC-I AP and reduced tumor growth in a CD8+ T cell-dependent manner. Mechanistically, SUSD6 forms a trimolecular complex with TMEM127 and MHC-I, which recruits WWP2 for MHC-I ubiquitination and lysosomal degradation. Together with the SUSD6/TMEM127/WWP2 gene signature, which negatively correlates with cancer survival, our findings define a membrane-associated MHC-I inhibitory axis as a potential therapeutic target for both leukemia and solid cancers.

Tyramine-Invertase Bioconjugate-Amplified Personal Glucose Meter Signaling for Ultrasensitive Immunoassay.

Highly sensitive and facile detection of low levels of protein markers is of great significance for the early diagnosis and efficacy monitoring of diseases. Herein, aided by an efficient tyramine-signal amplification (TSA) mechanism, we wish to report a simple but ultrasensitive immunoassay with signal readout on a portable personal glucose meter (PGM). In this study, the bioconjugates of tyramine and invertase (Tyr-inv), which act as the critical bridge to convert and amplify the protein concentration information into glucose, are prepared following a click chemistry reaction. Then, in the presence of a target protein, the sandwich immunoreaction between the immobilized capture antibody, the target protein, and the horseradish peroxidase (HRP)-conjugated detection antibody is specifically performed in a 96-well microplate. Subsequently, the specifically loaded HRP-conjugated detection antibodies will catalyze the amplified deposition of a large number of Tyr-inv molecules onto adjacent proteins through highly efficient TSA. Then, the deposited invertase, whose dosage can faithfully reflect the original concentration of the target protein, can efficiently convert sucrose to glucose. The amount of finally produced glucose is simply quantified by the PGM, realizing the highly sensitive detection of trace protein markers such as the carcinoembryonic antigen and alpha fetoprotein antigen at the fg/mL level. This method is simple, cost-effective, and ultrasensitive without the requirement of sophisticated instruments or specialized laboratory equipment, which may provide a universal and promising technology for highly sensitive immunoassay for in vitro diagnosis of diseases.

Transcriptome-wide identification of development related genes and pathways in Tribolium castaneum.

The growth and development in Tribolium castaneum were poorly understood at the transcriptome level. Currently, we identified 15,756, 9941 and 10,080 differentially expressed transcripts between late eggs VS early larvae, late larvae VS early pupae, and late pupae VS early adults of T. castaneum by RNA-seq, which was confirmed by qRT-PCR analysis on nine genes expression. Functional enrichment analysis indicated that DNA replication, cell cycle and insect hormone biosynthesis significantly enriched differentially expressed genes. The transcription of DNA replication and cell cycle genes decreased after hatching but increased after pupation. The juvenile hormone (JH) and ecdysteroid biosynthesis genes decreased after hatching, and the JH degradation genes were stimulated after pupation and eclosion while the ecdysteroid degradation gene CYP18A1 decreased after pupation. Silencing CYP18A1 elevated the titer of ecdysteroids and caused developmental arrest at the late larval stage. This study promotes the understanding of insect growth and development.

Eukaryotic initiation factor 6 modulates the metamorphosis and reproduction of Tribolium castaneum.

Eukaryotic initiation factor 6 (eIF6) is necessary for ribosome biogenesis and translation, but eIF6 has been poorly elucidated in insects. Phylogenetic analysis demonstrated that eIF6 originated from one ancestral gene among animals and exhibited specific duplication in Tribolium, yielding three homologues in Tribolium castaneum, eIF6, eIF6-like 1 (eIF6l1), and eIF6-like 2 (eIF6l2). It was found that eIF6 was highly expressed in the embryonic and early adult stages, eIF6l1 had peak expression at the adult stage, and eIF6l2 showed peak expression in late adults of T. castaneum. Tissue-specific analyses in late-stage larvae demonstrated that eIF6 was abundantly expressed in all tissues, while eIF6l1 and eIF6l2 had the highest expression in the gut and the lowest expression in the head of T. castaneum. Knockdown of eIF6 caused precocious pupation and eclosion, impaired ovary and testis development and completely repressed egg production. The expression levels of vitellogenin 1 (Vg1), Vg2 and Vg receptor (VgR) significantly decreased in ds-eIF6 females 5 days post-adult emergence. Silencing eIF6 activated ecdysteroid biosynthesis and juvenile hormone degradation but reduced the activity of insulin signalling in T. castaneum, which might mediate its roles in metamorphosis, reproduction and gene expression regulation. However, silence of eIF6l1 or eIF6l2 had no effects on metamorphosis and reproduction in T. castaneum. This study provides comprehensive information for eIF6 evolution and function in the insect.

Integration of the Ligase Chain Reaction with the CRISPR-Cas12a System for Homogeneous, Ultrasensitive, and Visual Detection of microRNA.

The ligase chain reaction (LCR), as a classic nucleic acid amplification technique, is popular in the detection of DNA and RNA due to its simplicity, powerfulness, and high specificity. However, homogeneous and ultrasensitive LCR detection is still quite challenging. Herein, we integrate the LCR with a CRISPR-Cas12a system to greatly promote the application of the LCR in a homogeneous fashion. By employing microRNA as the model target, we design LCR probes with specific protospacer adjacent motif sequences and the guide RNA. Then, the LCR is initiated by target microRNA, and the LCR products specifically bind to the guide RNA to activate the Cas12a system, triggering secondary signal amplification to achieve ultrasensitive detection of microRNA without separation steps. Moreover, by virtue of a cationic conjugated polymer, microRNA can not only be visually detected by naked eyes but also be accurately quantified based on RGB ratio analysis of images with no need of sophisticated instruments. The method can quantify microRNA up to 4 orders of magnitude, and the determination limit is 0.4 aM, which is better than those of other reported studies using CRISPR-Cas12a and can be compared with that of the reverse-transcription polymerase chain reaction. This study demonstrates that the CRISPR-Cas12a system can greatly expand the application of the LCR for the homogeneous, ultrasensitive, and visual detection of microRNA, showing great potential in efficient nucleic acid detection and in vitro diagnosis.

Multi gene mutation signatures in colorectal cancer patients: predict for the diagnosis, pathological classification, staging and prognosis.

BACKGROUND: Identifying gene mutation signatures will enable a better understanding for the occurrence and development of colorectal cancer (CRC), and provide some potential biomarkers for clinical practice. Currently, however, there is still few effective biomarkers for early diagnosis and prognostic judgment in CRC patients. The purpose was to identify novel mutation signatures for the diagnosis and prognosis of CRC. METHODS: Clinical information of 531 CRC patients and their sequencing data were downloaded from TCGA database (training group), and 53 clinical patients were collected and sequenced with targeted next generation sequencing (NGS) technology (validation group). The relationship between the mutation genes and the diagnosis, pathological type, stage and prognosis of CRC were compared to construct signatures for CRC, and then analyzed their relationship with RNA expression, immunocyte infiltration and tumor microenvironment (TME). RESULTS: Mutations of TP53, APC, KRAS, BRAF and ATM covered 97.55% of TCGA population and 83.02% validation patients. Moreover, 57.14% validation samples and 22.06% TCGA samples indicated that patients with mucinous adenocarcinoma tended to have BRAF mutation, but no TP53 mutation. Mutations of TP53, PIK3CA, FAT4, FMN2 and TRRAP had a remarkable difference between I-II and III-IV stage patients (P < 0.0001). Besides, the combination of PIK3CA, LRP1B, FAT4 and ROS1 formed signatures for the prognosis and survival of CRC patients. The mutations of TP53, APC, KRAS, BRAF, ATM, PIK3CA, FAT4, FMN2, TRRAP, LRP1B, and ROS1 formed the signatures for predicting diagnosis and prognosis of CRC. Among them, mutation of TP53, APC, KRAS, BRAF, ATM, PIK3CA, FAT4 and TRRAP significantly reduced their RNA expression level. Stromal score, immune score and ESTIMATE score were lower in patients with TP53, APC, KRAS, PIK3CA mutation compared non-mutation patients. All the 11 gene mutations affected the distributions of immune cells. CONCLUSION: This study constructed gene mutation signatures for the diagnosis, treatment and prognosis in CRC, and proved that their mutations affected RNA expression levels, TME and immunocyte infiltration. Our results put forward further insights into the genotype of CRC.

Integration of magnetic separation and real-time ligation chain reaction for detection of uracil-DNA glycosylase.

Uracil-DNA glycosylase (UDG) is a protein enzyme that initiates the base excision repair pathway for maintaining genome stability. Sensitive detection of UDG activity is important in the study of many biochemical processes and clinical applications. Here, a method for detecting UDG is proposed by integrating magnetic separation and real-time ligation chain reaction (LCR). First, a DNA substrate containing uracil base is designed to be conjugated to the magnetic beads. By introducing a DNA complementary to the DNA substrate, the uracil base is recognized and removed by UDG to form an apurinic/apyrimidinic (AP) site. The DNA substrate is then cut off from the AP site by endonuclease IV, releasing a single-strand DNA (ssDNA). After magnetic separation, the ssDNA is retained in the supernatant and then detected by real-time LCR. The linear range of the method is 5 × 10-4 to 5 U/mL with four orders of magnitude, and the detection limit is 2.7 × 10-4 U/mL. In the assay, ssDNA template obtained through magnetic separation can prevent other DNA from affecting the subsequent LCR amplification reaction, which provides a simple, sensitive, specific, and universal way to detect UDG and other repair enzymes. Furthermore, the real-time LCR enables the amplification reaction and fluorescence detection simultaneously, which simplifies the operation, avoids post-contamination, and widens the dynamic range. Therefore, the integration of magnetic separation and real-time LCR opens a new avenue for the detection of UDG and other DNA repair enzymes.

Effect of Distance from Catalytic Synergy Group to Iron Porphyrin Center on Activity of G-Quadruplex/Hemin DNAzyme.

G-quadruplex/Hemin (G4/Hemin) complex has been widely used in biocatalysis and analytical applications. Meanwhile, compared with natural proteinous enzyme, its low catalytic activity is still limiting its applications. Even though several methods have been developed to enhance the peroxidation efficiency, the important core of the G4 design based enhancement mechanism is still indistinct. Here, we focus the mechanism study on the two most important microdomains: the iron porphyrin center and the catalytic synergy group within the 3' flanking. These microdomains not only provide the pocket for the combination of substrate, but also offer the axial coordination for the accelerated formation of Compound I (catalytic intermediate). In order to obtain a more suitable space layout to further accelerate the catalytic process, we have used the bases within the 3' flanking to precisely regulate the distance between microdomains. Finally, the position-dependent effect on catalytic enhancement is observed. When dC is positioned at the second-position of 3' flanking, the newly obtained DNAzyme achieves an order of magnitude improvement compared to parent G4/Hemin in catalytic activity. The results highlight the influence of the distance between the catalytic synergy group and iron porphyrin center on the activity of DNAzyme, and provide insightful information for the design of highly active DNAzymes.

Recent advances in microRNA detection.

The development of simple, robust, and reliable microRNA (miRNA) detection methods is of great significance in the studies of the biological function of miRNAs, molecular diagnostics, treatment of diseases, and targeted drugs. In recent years, with the increasing development of miRNA research, lots of novel approaches were developed for the detection of miRNA in terms of sensitivity, specificity, multiplicity, in situ imaging, etc. In particular, nucleic acid amplification-based methods and many detection techniques such as droplet digital PCR (ddPCR), electrochemiluminescence (ECL), surface-enhanced Raman spectroscopy (SERS), and mass spectrometry (MS) have been employed widely for the highly sensitive detection of miRNA. New progress in miRNA detection has accelerated miRNA functional research and clinical diagnostics. In this review, we summarize the recent progress in the development of miRNA detection methods and new applications. This review will provide guidelines for the development of more advanced miRNA detection methods with high sensitivity and specificity, and applicability to biochemical research, disease diagnosis and therapy.

Multiplex detection of microRNAs by combining molecular beacon probes with T7 exonuclease-assisted cyclic amplification reaction.

A simple, highly sensitive, and specific assay was developed for the homogeneous and multiplex detection of microRNAs (miRNAs) by combining molecular beacon (MB) probes and T7 exonuclease-assisted cyclic amplification. An MB probe with five base pairs in the stem region without special modification can effectively prevent the digestion by T7 exonuclease. Only in the presence of target miRNA is the MB probe hybridized with the target miRNA, and then digested by T7 exonuclease in the 5' to 3' direction. At the same time, the target miRNA is released and subsequently initiates the nuclease-assisted cyclic digestion process, generating enhanced fluorescence signal significantly. The results show that the combination of T7 exonuclease-assisted cyclic amplification reaction and MB probe possesses higher sensitivity for miRNA detection. Moreover, multiplex detection of miRNAs was successfully achieved by designing two MB probes labeled with FAM and Cy3, respectively. As a result, the method opens a new pathway for the sensitive and multiplex detection of miRNAs as well as clinical diagnosis. Graphical Abstract A simple, highly sensitive, and specific assay was developed for the detection of microRNAs by combining molecular beacon probes with T7 exonuclease-assisted cyclic amplification reaction.

Cationic Conjugated Polymers-Induced Quorum Sensing of Bacteria Cells.

Bacteria quorum sensing (QS) has attracted significant interest for understanding cell-cell communication and regulating biological functions. In this work, we demonstrate that water-soluble cationic conjugated polymers (PFP-G2) can interact with bacteria to form aggregates through electrostatic interactions. With bacteria coated in the aggregate, PFP-G2 can induce the bacteria QS system and prolong the time duration of QS signal molecules (autoinducer-2 (AI-2)) production. The prolonged AI-2 can bind with specific protein and continuously regulate downstream gene expression. Consequently, the bacteria show a higher survival rate against antibiotics, resulting in decreased antimicrobial susceptibility. Also, AI-2 induced by PFP-G2 can stimulate 55.54 ± 12.03% more biofilm in E. coli. This method can be used to understand cell-cell communication and regulate biological functions, such as the production of signaling molecules, antibiotics, other microbial metabolites, and even virulence.

A simple molecular beacon with duplex-specific nuclease amplification for detection of microRNA.

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene activity, promoting or inhibiting cell proliferation, migration and apoptosis. Abnormal expression of miRNAs is associated with many diseases. Therefore, it is essential to establish a simple, rapid and sensitive miRNA detection method. In this paper, based on a simple molecular beacon (MB) and duplex-specific nuclease (DSN), we developed a target recycling amplification method for miRNA detection. By controlling the number of stem bases to 5, the MB probe used in this method can be prevented from hydrolysis by DSN without special modification. This assay is direct and simple to quantitatively detect miRNA with high sensitivity and specificity. The MB probe design provides a new strategy for nuclease-based amplification reaction.

Multifunctional assembly of micrometer-sized colloids for cell sorting.

Compared to the extensively studied nanometer-sized colloids, less attention has been paid to the assembly of micrometer-sized colloids with multifunctional characteristics. To address this need, a bottom-up approach is developed for constructing self-assemblies of micrometer-sized magnetic colloids possessing multifunctionality, including magnetic, optical, and biological activities. Biotinylated oligo (p-phenylene vinylene) (OPV) derivatives are designed to mediate the self-assembly of streptavidin-modified magnetic beads. The optical element OPV derivatives provide a fluorescence imaging ability for tracing the assembly process. Target cells can be recognized and assembled by the colloidal assembly with bioactive element antibodies. The colloidal assembly reveals better cell isolation performance by its amplified magnetic response in comparison to monodisperse colloids. The self-assembly of micrometer-sized magnetic colloids through a combination of different functional ingredients to realize multifunction is conceptually simple and easy to achieve.

Highly sensitive and specific multiplexed microRNA quantification using size-coded ligation chain reaction.

As important regulators of gene expression, microRNAs (miRNAs) are emerging as novel biomarkers with powerful predictive value in diagnosis and prognosis for several diseases, especially for cancers. There is a great demand for flexible multiplexed miRNA quantification methods that can quantify very low levels of miRNA targets with high specificity. For further analysis of miRNA signatures in biological samples, we describe here a highly sensitive and specific method to detect multiple miRNAs simultaneously in total RNA. First, we rationally design one of the DNA probes modified with two ribonucleotides, which can greatly improve the ligation efficiency of DNA probes templated by miRNAs. With the modified DNA probes, the ligation chain reaction (LCR) can be well applied to miRNA detection and as low as 0.2 fM miRNA can be accurately determined. High specificity to clearly discriminate a single nucleotide difference among miRNA sequences can also be achieved. By simply coding the DNA probes with different length of oligo (dA) for different miRNA targets, multiple miRNAs can be simultaneously detected in one LCR reaction. In our proof of principle work, we detect three miRNAs: let-7a, mir-92a, and mir-143, which can also be simultaneously detected in as small as 2 ng of total RNA sample.

Associated analysis of DNA methylation for cancer detection using CCP-based FRET technique.

This paper describes an associated analysis method of DNA methylation for the detection of cancer using an optically amplifying cationic conjugated polymer (CCP, poly{(1,4-phenylene)-2,7-[9,9-bis(6'-N,N,N-trimethyl ammonium)-hexyl fluorene] dibromide)}. Genomic DNA is digested by methylation-sensitive restriction endonuclease, followed by PCR amplification to incorporate fluorescein-labeled dNTP. Only methylated DNA can be amplified by PCR, and the methylation level is detected through fluorescence resonance energy transfer (FRET) between CCP and fluorescein that is incorporated into the PCR product. The methylation levels of RASSF1A, OPCML, and HOXA9 promoters of 35 ovarian cancer samples and 11 normal samples were assayed. In accordance with the degree of methylation levels, they are clustered to three sections and assigned a value. Through an associated analysis, we acquired a threshold for cancer detection with a sensitivity of 85.7%. The assay takes about 20 h to obtain the detection results and shows great potential as a useful tool for diagnostic and screening of cancer.

MicroRNAs regulate bone metabolism.

Osteoporosis is caused by an unbalance between bone formation and bone resorption. Bone homeostasis is regulated by intricate mechanisms. Recently, a novel class of regulatory factors termed microRNAs (miRNAs) has been found to play a crucial role in cell cycle control, apoptosis and other cellular processes including metabolism and differentiation. Published data have shown that some miRNAs regulate bone homeostasis, including bone formation, resorption, remodeling, repair and bone-related disease, by regulating the expression of certain cytokines and transcription factors. This review highlights the current knowledge of miRNAs and their involvement in the regulation of bone formation, bone resorption and the pathways regulating the progression of osteoporosis.

Cost-effectiveness of tislelizumab plus chemotherapy vs chemotherapy as first-line treatment of PD-L1 positive advanced gastric or gastroesophageal junction adenocarcinoma from a Chinese perspective.

BACKGROUND: This work was designed to assess the cost-effectiveness of front-line tislelizumab plus chemotherapy (TIS+Chemo) in advanced gastric cancer (GC) or gastroesophageal junction cancer (GEJC) with positive expression of programmed cell death ligand 1 (PD-L1) from the perspective of Chinese healthcare system. RESEARCH DESIGN AND METHODS: A 10-year partitioned survival model was undertaken utilizing clinical data from RATIONALE 305. Costs and utilities were both discounted at an annual rate of 5%. The primary outcome was incremental cost-effectiveness ratios (ICERs) and calculated as the cost per quality-adjusted life years (QALYs). The willingness-to-pay (WTP) threshold was set as $18,625/QALY. Only direct medical costs were considered. Sensitivity analyses and subgroup analyses were performed to evaluate the robustness of the model. RESULTS: In the base-case analysis, the incremental cost and effectiveness associated with TIS+Chemo vs Chemo was 7,361 and 0.38 QALYs, respectively, leading to an ICER of 19,371/QALY. At the WTP threshold of $18,625/QALY, the TIS+Chemo was not a cost-effective first-line treatment option. The model outcomes were robust. CONCLUSIONS: TIS+Chemo did not provide a cost-effective approach for PD-L1 positive advanced GC/GEJC in China setting. However, TIS+Chemo might be cost-effective in provinces with higher WTP threshold. CLINICAL TRIAL REGISTRATION: RATIONALE 305, www.clinicaltrials.gov, identifier is NCT03777657.

Rapid response to fifth-line brigatinib plus entrectinib in an ALK-rearranged lung adenocarcinoma with an acquired ETV6-NTRK3 fusion: a case report.

The management of non-small cell lung cancer (NSCLC), specifically targeting the anaplastic lymphoma kinase (ALK) with tyrosine kinase inhibitors (TKIs), is challenged by the emergence of therapeutic resistance. Resistance mechanisms to ALK TKIs can be broadly classified into ALK-dependent and ALK-independent pathways. Here, we present a case with lung adenocarcinoma (LUAD) harboring an ALK rearrangement. The patient had developed resistance to sequential ALK TKI therapies, with an acquired ETV6-NTRK3 (E4:N14) fusion as a potential mechanism of ALK-independent resistance to lorlatinib. Subsequently, the patient was treated with the combination of brigatinib plus entrectinib and demonstrated a positive response, achieving an 8-month progression-free survival. Our case provides a potential treatment option for LUAD patients with ALK rearrangements and highlights the utility of next-generation sequencing (NGS) in uncovering genetic alterations that can guide the selection of effective treatment strategies.

Comparison of genes involved in brain development: insights into the organization and evolution of the telencephalic pallium.

The mechanisms underlying the organization and evolution of the telencephalic pallium are not yet clear.. To address this issue, we first performed comparative analysis of genes critical for the development of the pallium (Emx1/2 and Pax6) and subpallium (Dlx2 and Nkx1/2) among 500 vertebrate species. We found that these genes have no obvious variations in chromosomal duplication/loss, gene locus synteny or Darwinian selection. However, there is an additional fragment of approximately 20 amino acids in mammalian Emx1 and a poly-(Ala)6-7 in Emx2. Lentiviruses expressing mouse or chick Emx2 (m-Emx2 or c-Emx2 Lv) were injected into the ventricle of the chick telencephalon at embryonic Day 3 (E3), and the embryos were allowed to develop to E12-14 or to posthatchling. After transfection with m-Emx2 Lv, the cells expressing Reelin, Vimentin or GABA increased, and neurogenesis of calbindin cells changed towards the mammalian inside-out pattern in the dorsal pallium and mesopallium. In addition, a behavior test for posthatched chicks indicated that the passive avoidance ratio increased significantly. The study suggests that the acquisition of an additional fragment in mammalian Emx2 is associated with the organization and evolution of the mammalian pallium.

Multiplex detection of DNA mutations by the fluorescence fingerprint spectrum technique.

A fingerprint spectrum technique that utilizes cationic conjugated-polymer-based fluorescence resonance energy transfer (FRET) is used for multiplex detection of DNA mutations. This method detects as low as 5 % mutation of the total DNA. Ten PIK3CA mutations originating from 30 clinical breast cancer samples could be detected.