Synthesizing a Genetic Sensor Based on CRISPR-Cas9 for Specifically Killing p53-Deficient Cancer Cells

CRISPR-based gene expression platform for precise regulation of bladder cancer

The development of compact CRISPR systems has facilitated delivery but has concurrently reduced gene editing efficiency, thereby limiting the further utilization of CRISPR systems. Enhancing the efficiency of CRISPR systems poses a challenging task and holds significant implications for the advancement of biotechnology. In our work, we report a synthetic dual-antibody system that can stably exist in the intracellular environment, specifically inhibiting the functions of NF-κB and β-catenin. This not only elevates the transgenic expression of the CRISPR system by suppressing the innate immune response within cells to enhance the gene editing efficiency but also demonstrates a notable tumor inhibitory effect. Based on the specific output expression regulation of CRISPR-CasΦ, we constructed a CRISPR-based gene expression platform, which includes sensor modules for detecting intracellular β-catenin and NF-κB, as well as an SDA module to enhance overall efficiency. In vitro experiments revealed that the CRISPR-based gene expression platform exhibited superior CDK5 expression inhibition efficiency and specific cytotoxicity towards tumor cells. In vitro experiments, we found that CRISPR-based gene expression platforms can selectively kill bladder cancer cells through T cell-mediated cytotoxicity. Our design holds significant assistant potential of transgene therapy and may offer the capability to treat other diseases requiring transgene therapy.

Therapeutically targeting the unique disease landscape of pediatric high-grade gliomas

Pediatric high-grade gliomas (pHGG) are a rare yet devastating malignancy of the central nervous system's glial support cells, affecting children, adolescents, and young adults. Tumors of the central nervous system account for the leading cause of pediatric mortality of which high-grade gliomas present a significantly grim prognosis. While the past few decades have seen many pediatric cancers experiencing significant improvements in overall survival, the prospect of survival for patients diagnosed with pHGGs has conversely remained unchanged. This can be attributed in part to tumor heterogeneity and the existence of the blood-brain barrier. Advances in discovery research have substantiated the existence of unique subgroups of pHGGs displaying alternate responses to different therapeutics and varying degrees of overall survival. This highlights a necessity to approach discovery research and clinical management of the disease in an alternative subtype-dependent manner. This review covers traditional approaches to the therapeutic management of pHGGs, limitations of such methods and emerging alternatives. Novel mutations which predominate the pHGG landscape are highlighted and the therapeutic potential of targeting them in a subtype specific manner discussed. Collectively, this provides an insight into issues in need of transformative progress which arise during the management of pHGGs.

Phase 1b trial of tagraxofusp in combination with azacitidine with or without venetoclax in acute myeloid leukemia

ABSTRACT

CD123, a subunit of the interleukin-3 receptor, is expressed on ∼80% of acute myeloid leukemias (AMLs). Tagraxofusp (TAG), recombinant interleukin-3 fused to a truncated diphtheria toxin payload, is a first-in-class drug targeting CD123 approved for treatment of blastic plasmacytoid dendritic cell neoplasm. We previously found that AMLs with acquired resistance to TAG were re-sensitized by the DNA hypomethylating agent azacitidine (AZA) and that TAG-exposed cells became more dependent on the antiapoptotic molecule BCL-2. Here, we report a phase 1b study in 56 adults with CD123-positive AML or high-risk myelodysplastic syndrome (MDS), first combining TAG with AZA in AML/MDS, and subsequently TAG, AZA, and the BCL-2 inhibitor venetoclax (VEN) in AML. Adverse events with 3-day TAG dosing were as expected, without indication of increased toxicity of TAG or AZA+/-VEN in combination. The recommended phase 2 dose of TAG was 12 μg/kg/day for 3 days, with 7-day AZA +/- 21-day VEN. In an expansion cohort of 26 patients (median age 71) with previously untreated European LeukemiaNet adverse-risk AML (50% TP53 mutated), triplet TAG-AZA-VEN induced response in 69% (n=18/26; 39% complete remission [CR], 19% complete remission with incomplete count recovery [CRi], 12% morphologic leukemia-free state [MLFS]). Among 13 patients with TP53 mutations, 7/13 (54%) achieved CR/CRi/MLFS (CR = 4, CRi = 2, MLFS = 1). Twelve of 17 (71%) tested responders had no flow measurable residual disease. Median overall survival and progression-free survival were 14 months (95% CI, 9.5-NA) and 8.5 months (95% CI, 5.1-NA), respectively. In summary, TAG-AZA-VEN shows encouraging safety and activity in high-risk AML, including TP53-mutated disease, supporting further clinical development of TAG combinations. The study was registered on ClinicalTrials.gov as #NCT03113643.

Comprehensive review of CRISPR-based gene editing: mechanisms, challenges, and applications in cancer therapy

The CRISPR system is a revolutionary genome editing tool that has the potential to revolutionize the field of cancer research and therapy. The ability to precisely target and edit specific genetic mutations that drive the growth and spread of tumors has opened up new possibilities for the development of more effective and personalized cancer treatments. In this review, we will discuss the different CRISPR-based strategies that have been proposed for cancer therapy, including inactivating genes that drive tumor growth, enhancing the immune response to cancer cells, repairing genetic mutations that cause cancer, and delivering cancer-killing molecules directly to tumor cells. We will also summarize the current state of preclinical studies and clinical trials of CRISPR-based cancer therapy, highlighting the most promising results and the challenges that still need to be overcome. Safety and delivery are also important challenges for CRISPR-based cancer therapy to become a viable clinical option. We will discuss the challenges and limitations that need to be overcome, such as off-target effects, safety, and delivery to the tumor site. Finally, we will provide an overview of the current challenges and opportunities in the field of CRISPR-based cancer therapy and discuss future directions for research and development. The CRISPR system has the potential to change the landscape of cancer research, and this review aims to provide an overview of the current state of the field and the challenges that need to be overcome to realize this potential.

Recent advances in targeting the "undruggable" proteins: from drug discovery to clinical trials

Undruggable proteins are a class of proteins that are often characterized by large, complex structures or functions that are difficult to interfere with using conventional drug design strategies. Targeting such undruggable targets has been considered also a great opportunity for treatment of human diseases and has attracted substantial efforts in the field of medicine. Therefore, in this review, we focus on the recent development of drug discovery targeting "undruggable" proteins and their application in clinic. To make this review well organized, we discuss the design strategies targeting the undruggable proteins, including covalent regulation, allosteric inhibition, protein-protein/DNA interaction inhibition, targeted proteins regulation, nucleic acid-based approach, immunotherapy and others.

CRISPR/Cas9-based application for cancer therapy: Challenges and solutions for non-viral delivery

CRISPR/Cas9 genome editing is a promising therapeutic technique, which makes precise and rapid gene editing technology possible on account of its high sensitivity and efficiency. CRISPR/Cas9 system has been proved to able to effectively disrupt and modify genes, which shows great potential for cancer treatment. Current researches proves that virus vectors are capable of effectively delivering the CRISPR/Cas9 system, but immunogenicity and carcinogenicity caused by virus transmission still trigger serious consequences. Therefore, the greatest challenge of CRISPR/Cas9 for cancer therapy lies on how to deliver it to the target tumor site safely and effectively. Non-viral delivery systems with specific targeting, high loading capacity, and low immune toxicity are more suitable than viral vectors, which limited by uncontrollable side effects. Their medical advances and applications have been widely concerned. Herein, we present the molecule mechanism and different construction strategies of CRISPR/Cas9 system for editing genes at the beginning of this research. Subsequently, several common CRISPR/Cas9 non-viral deliveries for cancer treatment are introduced. Lastly, based on the main factors limiting the delivery efficiency of non-viral vectors proposed in the existing researches and literature, we summarize and discuss the main methods to solve these limitations in the existing tumor treatment system, aiming to introduce further optimization and innovation of the CRISPR/Cas9 non-viral delivery system suitable for cancer treatment.

Mutant p53 in cancer: from molecular mechanism to therapeutic modulation

TP53, a crucial tumor suppressor gene, is the most commonly mutated gene in human cancers. Aside from losing its tumor suppressor function, mutant p53 (mutp53) often acquires inherent, novel oncogenic functions, which is termed "gain-of-function". Emerging evidence suggests that mutp53 is highly associated with advanced malignancies and poor prognosis, which makes it a target for development of novel cancer therapies. Herein, we provide a summary of our knowledge of the mutp53 types and mutp53 spectrum in cancers. The mechanisms of mutp53 accumulation and gain-of-function are also summarized. Furthermore, we discuss the gain-of-function of mutp53 in cancers: genetic instability, ferroptosis, microenvironment, and stemness. Importantly, the role of mutp53 in the clinic is also discussed, particularly with regard to chemotherapy and radiotherapy. Last, emphasis is given to emerging strategies on how to target mutp53 for tumor therapy. Thus, this review will contribute to better understanding of the significance of mutp53 as a target for therapeutic strategies.

Application of synthetic biology in bladder cancer

ABSTRACT

Bladder cancer (BC) is the most common malignant tumor of the genitourinary system. The age of individuals diagnosed with BC tends to decrease in recent years. A variety of standard therapeutic options are available for the clinical management of BC, but limitations exist. It is difficult to surgically eliminate small lesions, while radiation and chemotherapy damage normal tissues, leading to severe side effects. Therefore, new approaches are required to improve the efficacy and specificity of BC treatment. Synthetic biology is a field emerging in the last decade that refers to biological elements, devices, and materials that are artificially synthesized according to users' needs. In this review, we discuss how to utilize genetic elements to regulate BC-related gene expression periodically and quantitatively to inhibit the initiation and progression of BC. In addition, the design and construction of gene circuits to distinguish cancer cells from normal cells to kill the former but spare the latter are elaborated. Then, we introduce the development of genetically modified T cells for targeted attacks on BC. Finally, synthetic nanomaterials specializing in detecting and killing BC cells are detailed. This review aims to describe the innovative details of the clinical diagnosis and treatment of BC from the perspective of synthetic biology.

Intra Q-body: an antibody-based fluorogenic probe for intracellular proteins that allows live cell imaging and sorting

Although intracellular biomarkers can be imaged with fluorescent dye(s)-labeled antibodies, the use of such probes for precise imaging of intracellular biomarkers in living cells remains challenging due to background noise from unbound probes. Herein, we describe the development of a conditionally active Fab-type Quenchbody (Q-body) probe derived from a monoclonal antibody (DO-1) with the ability to both target and spatiotemporally visualize intracellular p53 in living cells with low background signal. p53 is a key tumor suppressor and validated biomarker for cancer diagnostics and therapeutics. The Q-body displayed up to 27-fold p53 level-dependent fluorescence enhancement in vitro with a limit of detection of 0.72 nM. In fixed and live cells, 8.3- and 8.4-fold enhancement was respectively observed. Furthermore, we demonstrate live-cell sorting based on p53 expression. This study provides the first evidence of the feasibility and applicability of Q-body probes for the live-cell imaging of intrinsically intracellular proteins and opens a novel avenue for research and diagnostic applications on intracellular target-based live-cell sorting.

A fluorescent immunosensor that lights up tumor biomarker p53 in living cells was developed based on the Q-body technology. The technology was further applied to the live cell monitoring of p53 levels, and live cell sorting based on p53 expression.

Manipulating the NKG2D Receptor-Ligand Axis Using CRISPR: Novel Technologies for Improved Host Immunity

The activating immune receptor natural killer group member D (NKG2D) and its cognate ligands represent a fundamental surveillance system of cellular distress, damage or transformation. Signaling through the NKG2D receptor-ligand axis is critical for early detection of viral infection or oncogenic transformation and the presence of functional NKG2D ligands (NKG2D-L) is associated with tumor rejection and viral clearance. Many viruses and tumors have developed mechanisms to evade NKG2D recognition via transcriptional, post-transcriptional or post-translational interference with NKG2D-L, supporting the concept that circumventing immune evasion of the NKG2D receptor-ligand axis may be an attractive therapeutic avenue for antiviral therapy or cancer immunotherapy. To date, the complexity of the NKG2D receptor-ligand axis and the lack of specificity of current NKG2D-targeting therapies has not allowed for the precise manipulation required to optimally harness NKG2D-mediated immunity. However, with the discovery of clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins, novel opportunities have arisen in the realm of locus-specific gene editing and regulation. Here, we give a brief overview of the NKG2D receptor-ligand axis in humans and discuss the levels at which NKG2D-L are regulated and dysregulated during viral infection and oncogenesis. Moreover, we explore the potential for CRISPR-based technologies to provide novel therapeutic avenues to improve and maximize NKG2D-mediated immunity.

Engineering L7Ae for RNA-Only Delivery Kill Switch Targeting CMS2 Type Colorectal Cancer Cells

The lack of specific-targeting therapy to precisely identify and kill malignant cells while sparing others is a great challenge in colorectal cancer (CRC) treatment. In the era of molecular classification of tumors, CRC has been grouped into four Consensus Molecular Subtypes. Accounting for 37% of all types, the CMS2 group (canonical type) shows distinguishing features: WNT and MYC signaling activation. In this study, we designed an RNA-only delivery kill switch to specifically eliminate CMS2 type CRC cells. The sensing and logic processing functions are integrated by the newly engineered L7Ae, which can not only detect the stability of β-catenin protein and the presence of cytoplasm located Myc/Myc-nick, but also do logic computation. The circuit specifically eliminated HCT-116 cells while sparing other kinds of cells, showing a proof-of-principle approach to precisely target CMS2 type CRC.

Synthesis of RNA-based gene regulatory devices for redirecting cellular signaling events mediated by p53

Rationale: The p53 gene is a well-known tumor suppressor, and its mutation often contributes to the occurrence and development of tumors. Due to the diversity and complexity of p53 mutations, there is still no effective p53 gene therapy. In this study, we designed and constructed an aptazyme switch that could effectively sense cellular wild-type p53 protein and regulate downstream gene function flexibly. The application of this artificial device in combination with Cre-LoxP and dCas9-VP64 tools achieved a precisely targeted killing effect on tumor cells. Methods: The affinity of the aptamer to p53 protein was verified by SPR. p53 aptazyme and gene circuits were chemically synthesized. The function of the gene circuit was detected by cell proliferation assay, apoptosis assay and Western blot. The nude mouse transplantation tumor experiment was used to evaluate the inhibitory effect of gene circuits on tumor cells in vivo. Results: The results of the SPR experiment showed that the p53 aptamer RNA sequence had a robust binding effect with p53 protein. The p53 aptazyme could efficiently sense wild-type p53 protein and initiate self-cleavage in cells. The Cre-p53 aptazyme gene circuit and dCas9-VP64/sgRNA mediated gene circuit designed based on p53 aptazyme significantly inhibited the growth and promoted the apoptosis of wild-type p53-deficient cancer cells in vitro. In addition, the gene circuits also had a significant inhibitory effect on tumors in vivo. Conclusion: The study developed a novel and efficient ribozyme switch for p53-specific recognition and provided a modular strategy for aptazyme binding to cellular proteins. In addition, the p53 aptazyme successfully inhibited tumor growth through a combined application with other synthetic biological tools, providing a new perspective for cancer therapy.

A Light-Inducible Split-dCas9 System for Inhibiting the Progression of Bladder Cancer Cells by Activating p53 and E-cadherin

Optogenetic systems have been increasingly investigated in the field of biomedicine. Previous studies had found the inhibitory effect of the light-inducible genetic circuits on cancer cell growth. In our study, we applied an AND logic gates to the light-inducible genetic circuits to inhibit the cancer cells more specifically. The circuit would only be activated in the presence of both the human telomerase reverse transcriptase (hTERT) and the human uroplakin II (hUPII) promoter. The activated logic gate led to the expression of the p53 or E-cadherin protein, which could inhibit the biological function of tumor cells. In addition, we split the dCas9 protein to reduce the size of the synthetic circuit compared to the full-length dCas9. This light-inducible system provides a potential therapeutic strategy for future bladder cancer.

Synthetic Artificial Long Non-coding RNA Shows Higher Efficiency in Specific Malignant Phenotype Inhibition Compared to the CRISPR/Cas Systems

Objective: Both oncogenic transcription factors (TFs) and microRNAs (miRNAs) play an important regulator in human cancer by transcriptional and post-transcriptional regulation, respectively. These phenomena raise questions about the ability of artificial device to regulate miRNAs and TFs simultaneously. In this study, we aimed to construct an artificial long non-coding RNA, “alncRNA,” which imitated CRISPR/Cas systems and to illuminate its therapeutic effects in bladder cancer cell lines. At the same time, we also compared the efficiency of alncRNA and CRISPR/Cas systems in regulating gene expression.

Study Design and Methods: Based on engineering principles of synthetic biology, we combined tandem arrayed cDNA sequences of aptamer for TFs with tandem arrayed cDNA copies of binding sites for the miRNAs to construct alncRNA. In order to prove the utility of this platform, we chose β -catenin, NF-κB, miR-940, and miR-495 as the functional targets and used the bladder cancer cell lines 5637 and T24 as the test models. Real-time Quantitative PCR (qPCR), dual-luciferase assay and relative phenotypic experiments were applied to severally test the expression of relative gene and therapeutic effects of our devices.

Result: Dual-luciferase assay indicated alncRNA could inhibit transcriptional activity of TFs. What’s more, the result of qPCR showed that expression levels of the relative TFs target genes and miRNAs were reduced by corresponding alncRNA and the inhibitory effect was better than CRIPSR dCas9-KRAB. By functional experiments, decreased cell proliferation, increased apoptosis, and motility inhibition were observed in alncRNA-infected bladder cells.

Conclusion: In summary, our synthetic devices indeed function as anti-tumor regulator, which synchronously accomplish transcriptional and post-transcriptional regulation in bladder cancer cell and show higher efficiency in specific malignant phenotype inhibition compared to the CRISPR/Cas systems. Most importantly, Anti-cancer effects were induced by the synthetic alncRNA in the bladder cancer lines. Our devices, therefore, provides a novel strategy for cancer therapy and could be a useful “weapon” for cancer cell.

Mutant p53 in Cancer Progression and Targeted Therapies

TP53 is the most frequently mutated tumor suppressor gene in human cancer. The majority of mutations of p53 are missense mutations, leading to the expression of the full length p53 mutant proteins. Mutant p53 (Mutp53) proteins not only lose wild-type p53-dependent tumor suppressive functions, but also frequently acquire oncogenic gain-of-functions (GOF) that promote tumorigenesis. In this review, we summarize the recent advances in our understanding of the oncogenic GOF of mutp53 and the potential therapies targeting mutp53 in human cancers. In particular, we discuss the promising drugs that are currently under clinical trials as well as the emerging therapeutic strategies, including CRISPR/Cas9 based genome edition of mutant TP53 allele, small peptide mediated restoration of wild-type p53 function, and immunotherapies that directly eliminate mutp53 expressing tumor cells.

Improving transgene expression and CRISPR-Cas9 efficiency with molecular engineering-based molecules

As a novel and robust gene‐editing tool, the Clustered Regularly Interspaced Short Palindromic Repeats CRISPR‐associated protein 9 (CRISPR‐Cas9) system has revolutionized gene therapy. Plasmid vector delivery is the most commonly used method for integrating the CRISPR‐Cas9 system into cells. However, such foreign cytosolic DNAs trigger an innate immune response (IIR) within cells, which can hinder gene editing by inhibiting transgene expression. Although some small molecules have been shown to avoid the action of IIR on plasmids, they only work on a single target and may also affect cell viability. A genetic approach that works at a comprehensive level for manipulating IIR is still lacking. Here, we designed and constructed several artificial nucleic acid molecules (ANAMs), which are combinations of aptamers binding to two key players of IIR (β‐catenin and NF‐κB). ANAMs strongly inhibited the IIR in cells, thus improving transgene expression. We also used ANAMs to improve the gene‐editing efficiency of the CRISPR‐Cas9 system and its derivatives, thus enhancing the apoptosis of cancer cells induced by CRISPR‐Cas9. ANAMs can be valuable tools for improving transgene expression and gene editing in mammalian cells.

Therapeutic Editing of the TP53 Gene: Is CRISPR/Cas9 an Option?

The TP53 gene encodes the transcription factor and oncosuppressor p53 protein that regulates a multitude of intracellular metabolic pathways involved in DNA damage repair, cell cycle arrest, apoptosis, and senescence. In many cases, alterations (e.g., mutations of the TP53 gene) negatively affect these pathways resulting in tumor development. Recent advances in genome manipulation technologies, CRISPR/Cas9, in particular, brought us closer to therapeutic gene editing for the treatment of cancer and hereditary diseases. Genome-editing therapies for blood disorders, blindness, and cancer are currently being evaluated in clinical trials. Eventually CRISPR/Cas9 technology is expected to target TP53 as the most mutated gene in all types of cancers. A majority of TP53 mutations are missense which brings immense opportunities for the CRISPR/Cas9 system that has been successfully used for correcting single nucleotides in various models, both in vitro and in vivo. In this review, we highlight the recent clinical applications of CRISPR/Cas9 technology for therapeutic genome editing and discuss its perspectives for editing TP53 and regulating transcription of p53 pathway genes.

Unraveling the structure and biological functions of RNA triple helices

It has been nearly 63 years since the first characterization of an RNA triple helix in vitro by Gary Felsenfeld, David Davies, and Alexander Rich. An RNA triple helix consists of three strands: A Watson–Crick RNA double helix whose major‐groove establishes hydrogen bonds with the so‐called “third strand”. In the past 15 years, it has been recognized that these major‐groove RNA triple helices, like single‐stranded and double‐stranded RNA, also mediate prominent biological roles inside cells. Thus far, these triple helices are known to mediate catalysis during telomere synthesis and RNA splicing, bind to ligands and ions so that metabolite‐sensing riboswitches can regulate gene expression, and provide a clever strategy to protect the 3′ end of RNA from degradation. Because RNA triple helices play important roles in biology, there is a renewed interest in better understanding the fundamental properties of RNA triple helices and developing methods for their high‐throughput discovery. This review provides an overview of the fundamental biochemical and structural properties of major‐groove RNA triple helices, summarizes the structure and function of naturally occurring RNA triple helices, and describes prospective strategies to isolate RNA triple helices as a means to establish the “triplexome”.

This article is categorized under:

RNA Structure and Dynamics > RNA Structure and Dynamics

RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry

RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems

Circular RNA MAN2B2 promotes cell proliferation of hepatocellular carcinoma cells via the miRNA-217/MAPK1 axis

The increasing incidence of hepatocellular carcinoma (HCC) is a major challenge worldwide. In the past few years, an increasing number of studies have suggested that circular RNAs (circRNAs) play an important role in the development of human tumors, including HCC, but our understanding of their function is still limited. In this study, we investigated differences in the expression of circRNA MAN2B2 (circMAN2B2) in hepatocellular tissues and paired normal tissues. We found that knockdown of circMAN2B2 expression in the HCC cell lines Hep-G2 and Huh-7 significantly inhibited cell proliferation by sponging (miRNA) miR-217 and inhibiting its function. Through a series of experiments, we also demonstrated that miR-217 functioned as a tumor suppressor molecule in HCC cells and regulated the expression of mitogen-activated protein kinase 1 (MAPK1). Restoration of MAPK1 rescued repression of cell proliferation induced by circMAN2B2 knockdown. In summary, our study indicated that circMAN2B2 acted as an onco-miRNA in HCC by sponging miRNA-217 to promote MAPK1 expression.

Engineering Cellular Signal Sensors based on CRISPR-sgRNA Reconstruction Approaches

The discovery of the CRISPR systems has enriched the application of gene therapy and biotechnology. As a type of robust and simple toolbox, the CRISPR system has greatly promoted the development of cellular signal sensors at the genomic level. Although CRISPR systems have demonstrated that they can be used in eukaryotic and even mammalian cells after extraction from prokaryotic cells, controlling their gene-editing activity remains a challenge. Here we summarize the advantages and disadvantages of building a CRIRPR-based signal sensor through sgRNA reconstruction, as well as possible ways to reprogram the signal network of cells. We also propose how to further improve the design of the current signal sensors based on sgRNA-riboswitch. We believe that the development of these technologies and the construction of platforms can further promote the development of environment detection, disease diagnosis, and gene therapy by means of synthetic biology.

Specifically blocking the fatty acid synthesis to inhibit the malignant phenotype of bladder cancer

Fatty acid synthesis is regulated by transcription factors SREBPs and their escort protein SCAP. Malignant cells become dependent on de novo lipogenesis, which sustains rapid proliferation and resistance to cellular stress. Increasing evidence showed SCAP participated in various disease processes including malignant tumors, which regulate transcription factors SREBPs Tumorigenesis is associated with incur glucose consumption and lipogenesis. In our study, we discovered that SCAP was upregulated in BC tissues. SCAP knockdown by CRISPR-Cas9 inhibit the cell proliferation, invasion and migration. Additionally, the cell apoptosis was facilitated. What's more, downregulation of SCAP could weaken the cancer-promoting effects of estrogen on BC. Our study revealed that SCAP played a carcinogenic role in BC and lipogenesis might promote the initiation of BC by inducing SCAP. Thus, Targeting SCAP may provide a promising means of treating BC and a new perspective for the tumorigenesis of bladder cancer.

A revolutionary tool: CRISPR technology plays an important role in construction of intelligentized gene circuits

With the development of synthetic biology, synthetic gene circuits have shown great applied potential in medicine, biology, and as commodity chemicals. An ultimate challenge in the construction of gene circuits is the lack of effective, programmable, secure and sequence-specific gene editing tools. The clustered regularly interspaced short palindromic repeat (CRISPR) system, a CRISPR-associated RNA-guided endonuclease Cas9 (CRISPR-associated protein 9)-targeted genome editing tool, has recently been applied in engineering gene circuits for its unique properties-operability, high efficiency and programmability. The traditional single-targeted therapy cannot effectively distinguish tumour cells from normal cells, and gene therapy for single targets has poor anti-tumour effects, which severely limits the application of gene therapy. Currently, the design of gene circuits using tumour-specific targets based on CRISPR/Cas systems provides a new way for precision cancer therapy. Hence, the application of intelligentized gene circuits based on CRISPR technology effectively guarantees the safety, efficiency and specificity of cancer therapy. Here, we assessed the use of synthetic gene circuits and if the CRISPR system could be used, especially artificial switch-inducible Cas9, to more effectively target and treat tumour cells. Moreover, we also discussed recent advances, prospectives and underlying challenges in CRISPR-based gene circuit development.

Applications of CRISPR-Cas in Bioengineering, Biotechnology, and Translational Research

CRISPR technology is rapidly evolving, and the scope of CRISPR applications is constantly expanding. CRISPR was originally employed for genome editing. Its application was then extended to epigenome editing, karyotype engineering, chromatin imaging, transcriptome, and metabolic pathway engineering. Now, CRISPR technology is being harnessed for genetic circuits engineering, cell signaling sensing, cellular events recording, lineage information reconstruction, gene drive, DNA genotyping, miRNA quantification, in vivo cloning, site-directed mutagenesis, genomic diversification, and proteomic analysis in situ. It has also been implemented in the translational research of human diseases such as cancer immunotherapy, antiviral therapy, bacteriophage therapy, cancer diagnosis, pathogen screening, microbiota remodeling, stem-cell reprogramming, immunogenomic engineering, vaccine development, and antibody production. This review aims to summarize the key concepts of these CRISPR applications in order to capture the current state of play in this fast-moving field. The key mechanisms, strategies, and design principles for each technological advance are also highlighted.