In vivo genome-wide CRISPR screen reveals breast cancer vulnerabilities and synergistic mTOR/Hippo targeted combination therapy

Hippophae Rhamnoides-derived Phytomedicine Nano-System Modulates Bax/Fas Pathways to Reduce Proliferation in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most common primary tumor of the breast with limited effectual drug availability. Therefore, the aim of the study is to develop an innovative phyto-nanomedicine (PNM) to cure TNBC with the least genotoxicity. Hereinafter, the sea buckthorn' extracted polyphenols (SBP), combine with metformin (MET), are synthesized as a novel PNM to evaluate its anti-tumor properties, effectiveness, and mechanism of action in TNBC in vitro and in vivo models. The SBP exhibits 16 new kinds of polyphenols that are been reported earlier which regulated cell development, proliferation, and programmed cell death (PCD) effectively. SBP-MET PNM inhibits MDA-MB-231 (47%), MDA-MB-436 (46%), and 4T1 (46%) cell proliferation but does not affect L929 normal murine cell development and successfully induce PCD (73.19%) in MDA-MB-231 cells. Mechanistically, in vivo SBP-MET proteome expression profiling reveals upregulation of proapoptotic Bax protein and activation of Fas signaling pathways convince downstream Daxx and FADD proteins, which further triggers Caspase-3 that prompts apoptosis in human TNBC cells by cleaving PARP-1 protein. Current findings establish innovative highly biocompatible phyto-nanomedicine that has significant potential to inhibit TNBC cell growth and induce regulated cell death (RCD) in vivo model, thereby opening a new arena for TNBC therapy.

Leveraging preclinical models of metastatic breast cancer

Women that present to the clinic with established breast cancer metastases have limited treatment options. Yet, the majority of preclinical studies are actually not directed at developing treatment regimens for established metastatic disease. In this review we will discuss the current state of preclinical macro-metastatic breast cancer models, including, but not limited to syngeneic GEMM, PDX and xenografts. Challenges within these models which are often overlooked include fluorophore-immunogenic neoantigens, differences in experimental vs spontaneous metastasis and tumor heterogeneity. Furthermore, due to cell plasticity in the tumor immune microenvironment (TIME) of the metastatic landscape, the treatment efficacy of newly approved immune checkpoint blockade (ICB) may differ in metastatic sites as compared to primary localized tumors.

Let's make it personal: CRISPR tools in manipulating cell death pathways for cancer treatment

Advancements in the CRISPR technology, a game-changer in experimental research, have revolutionized various fields of life sciences and more profoundly, cancer research. Cell death pathways are among the most deregulated in cancer cells and are considered as critical aspects in cancer development. Through decades, our knowledge of the mechanisms orchestrating programmed cellular death has increased substantially, attributed to the revolution of cutting-edge technologies. The heroic appearance of CRISPR systems have expanded the available screening platform and genome engineering toolbox to detect mutations and create precise genome edits. In that context, the precise ability of this system for identification and targeting of mutations in cell death signaling pathways that result in cancer development and therapy resistance is an auspicious choice to transform and accelerate the individualized cancer therapy. The concept of personalized cancer therapy stands on the identification of molecular characterization of the individual tumor and its microenvironment in order to provide a precise treatment with the highest possible outcome and minimum toxicity. This study explored the potential of CRISPR technology in precision cancer treatment by identifying and targeting specific cell death pathways. It showed the promise of CRISPR in finding key components and mutations involved in programmed cell death, making it a potential tool for targeted cancer therapy. However, this study also highlighted the challenges and limitations that need to be addressed in future research to fully realize the potential of CRISPR in cancer treatment.

The COMPASS complex maintains the metastatic capacity imparted by a subpopulation of cells in UPS

Intratumoral heterogeneity is common in cancer, particularly in sarcomas like undifferentiated pleomorphic sarcoma (UPS), where individual cells demonstrate a high degree of cytogenic diversity. Previous studies showed that a small subset of cells within UPS, known as the metastatic clone (MC), as responsible for metastasis. Using a CRISPR-based genomic screen in-vivo, we identified the COMPASS complex member Setd1a as a key regulator maintaining the metastatic phenotype of the MC in murine UPS. Depletion of Setd1a inhibited metastasis development in the MC. Transcriptome and chromatin sequencing revealed COMPASS complex target genes in UPS, such as Cxcl10, downregulated in the MC. Deleting Cxcl10 in non-MC cells increased their metastatic potential. Treating mice with human UPS xenografts with a COMPASS complex inhibitor suppressed metastasis without affecting tumor growth in the primary tumor. Our data identified an epigenetic program in a subpopulation of sarcoma cells that maintains metastatic potential.

YAP inhibition overcomes adaptive resistance in HER2-positive gastric cancer treated with trastuzumab via the AKT/mTOR and ERK/mTOR axis

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) is a heterogeneous GC subtype characterized by the overexpression of HER2. To date, few specific targeted therapies have demonstrated durable efficacy in HER2-positive GC patients, with resistance to trastuzumab typically emerging within 1 year. However, the mechanisms of resistance to trastuzumab remain incompletely understood, presenting a significant challenge to clinical practice.

METHODS

In this study, we integrated genetic screening and bulk transcriptome and epigenomic profiling to define the mechanisms mediating adaptive resistance to HER2 inhibitors and identify potential effective therapeutic strategies for treating HER2-positive GCs.

RESULTS

We revealed a potential association between adaptive resistance to trastuzumab in HER2-positive GC and the expression of YES-associated protein (YAP). Notably, our investigation revealed that long-term administration of trastuzumab triggers extensive chromatin remodeling and initiates YAP gene transcription in HER2-positive cells characterized by the initial inhibition and subsequent reactivation. Furthermore, treatment of HER2-positive GC cells and cell line-derived xenografts (CDX) models with YAP inhibitors in combination with trastuzumab was found to induce synergistic effects through the AKT/mTOR and ERK/mTOR pathways.

CONCLUSION

These findings underscore the pivotal role of reactivated YAP and mTOR signaling pathways in the development of adaptive resistance to trastuzumab and may serve as a promising joint target to overcome resistance to trastuzumab.

Targeting the DYRK1A kinase prevents cancer progression and metastasis and promotes cancer cells response to G1/S targeting chemotherapy drugs

Metastatic cancer remains incurable as patients eventually loose sensitivity to targeted therapies and chemotherapies, further leading to poor clinical outcome. Thus, there is a clear medical gap and urgent need to develop efficient and improved targeted therapies for cancer patients. In this study, we investigated the role of DYRK1A kinase in regulating cancer progression and evaluated the therapeutic potential of DYRK1A inhibition in invasive solid tumors, including colon and triple-negative breast cancers. We uncovered new roles played by the DYRK1A kinase. We found that blocking DYRK1A gene expression or pharmacological inhibition of its kinase activity via harmine efficiently blocked primary tumor formation and the metastatic tumor spread in preclinical models of breast and colon cancers. Further assessing the underlying molecular mechanisms, we found that DYRK1A inhibition resulted in increased expression of the G1/S cell cycle regulators while decreasing expression of the G2/M regulators. Combined, these effects release cancer cells from quiescence, leading to their accumulation in G1/S and further delaying/preventing their progression toward G2/M, ultimately leading to growth arrest and tumor growth inhibition. Furthermore, we show that accumulation of cancer cells in G1/S upon DYRK1A inhibition led to significant potentiation of G1/S targeting chemotherapy drug responses in vitro and in vivo. This study underscores the potential for developing novel DYRK1A-targeting therapies in colon and breast cancers and, at the same time, further defines DYRK1A pharmacological inhibition as a viable and powerful combinatorial treatment approach for improving G1/S targeting chemotherapy drugs treatments in solid tumors.

Genome-wide in vivo CRISPR screen identifies TGFβ3 as actionable biomarker of palbociclib resistance in triple negative breast cancer

Triple negative breast cancer (TNBC) remains exceptionally challenging to treat. While CDK4/6 inhibitors have revolutionized HR + breast cancer therapy, there is limited understanding of their efficacy in TNBC and meaningful predictors of response and resistance to these drugs remain scarce. We conducted an in vivo genome-wide CRISPR screen using palbociclib as a selection pressure in TNBC. Hits were prioritized using microarray data from a large panel of breast cancer cell lines to identify top palbociclib sensitizers. Our study defines TGFβ3 as an actionable determinant of palbociclib sensitivity that potentiates its anti-tumor effects. Mechanistically, we show that chronic palbociclib exposure depletes p21 levels, contributing to acquired resistance, and that TGFβ3 treatment can overcome this. This study defines TGFβ3 as an actionable biomarker that can be used to improve patient stratification for palbociclib treatment and exploits the synergistic interaction between CDK4/6 and TGFβ3 to propose a new combinatorial treatment for TNBC.

A synthetic lethal dependency on casein kinase 2 in response to replication-perturbing therapeutics in RB1-deficient cancer cells

Resistance to therapy commonly develops in patients with high-grade serous ovarian carcinoma (HGSC) and triple-negative breast cancer (TNBC), urging the search for improved therapeutic combinations and their predictive biomarkers. Starting from a CRISPR knockout screen, we identified that loss of RB1 in TNBC or HGSC cells generates a synthetic lethal dependency on casein kinase 2 (CK2) for surviving the treatment with replication-perturbing therapeutics such as carboplatin, gemcitabine, or PARP inhibitors. CK2 inhibition in RB1-deficient cells resulted in the degradation of another RB family cell cycle regulator, p130, which led to S phase accumulation, micronuclei formation, and accelerated PARP inhibition-induced aneuploidy and mitotic cell death. CK2 inhibition was also effective in primary patient-derived cells. It selectively prevented the regrowth of RB1-deficient patient HGSC organoids after treatment with carboplatin or niraparib. As about 25% of HGSCs and 40% of TNBCs have lost RB1 expression, CK2 inhibition is a promising approach to overcome resistance to standard therapeutics in large strata of patients.

Discovery platforms for RNA therapeutics

RNA therapeutics are emerging as a unique opportunity to drug currently "undruggable" molecules and diseases. While their advantages over conventional, small molecule drugs, their therapeutic implications and the tools for their effective in vivo delivery have been extensively reviewed, little attention has been so far paid to the technological platforms exploited for the discovery of RNA therapeutics. Here, we provide an overview of the existing platforms and ex vivo assays for RNA discovery, their advantages and disadvantages, as well as their main fields of application, with specific focus on RNA therapies that have reached either phase 3 or market approval.

A genome-wide CRISPR screen identified host genes essential for intracellular Brucella survival

Brucella is a zoonotic intracellular bacterium that poses threats to human health and economic security. Intracellular infection is a hallmark of the agent Brucella and a primary cause of distress, through which the bacterium regulates the host intracellular environment to promote its own colonization and replication, evading host immunity and pharmaceutical killing. Current studies of Brucella intracellular processes are typically premised on bacterial phenotype such as intracellular bacterial survival, followed by biochemical or molecular biological approaches to reveal detailed mechanisms. While such processes can deepen the understanding of Brucella-host interaction, the insights into host alterations in infection would be easily restricted to known pathways. In the current study, we applied CRISPR Cas9 screen to identify host genes that are most affected by Brucella infection on cell viability at the genomic level. As a result of CRISPR screening, we firstly identified that knockout of the negatively selected genes GOLGA6L6, DEFB103B, OR4F29, and ERCC6 attenuate the viability of both the host cells and intracellular Brucella, suggesting these genes to be potential therapeutic targets for Brucella control. In particular, knockout of DEFB103B diminished Brucella intracellular survival by altering host cell autophagy. Conversely, knockout of positive screening genes promoted intracellular proliferation of Brucella. In summary, we screened host genes at the genomic level throughout Brucella infection, identified host genes that are previously not recognized to be involved in Brucella infection, and provided targets for intracellular infection control.IMPORTANCEBrucella is a Gram-negative bacterium that infects common mammals causing arthritis, myalgia, neuritis, orchitis, or miscarriage and is difficult to cure with antibiotics due to its intracellular parasitism. Therefore, unraveling the mechanism of Brucella-host interactions will help controlling Brucella infections. CRISPR-Cas9 is a gene editing technology that directs knockout of individual target genes by guided RNA, from which genome-wide gene-knockout cell libraries can be constructed. Upon infection with Brucella, the cell library would show differences in viability as a result of the knockout and specific genes could be revealed by genomic DNA sequencing. As a result, genes affecting cell viability during Brucella infection were identified. Further testing of gene function may reveal the mechanisms of Brucella-host interactions, thereby contributing to clinical therapy.

Tumor immune evasion: insights from CRISPR screens and future directions

Despite the clinical success of cancer immunotherapies including immune checkpoint blockade and adoptive cellular therapies across a variety of cancer types, many patients do not respond or ultimately relapse; however, the molecular underpinnings of this are not fully understood. Thus, a system-level understating of the routes to tumor immune evasion is required to inform the design of the next generation of immunotherapy approaches. CRISPR screening approaches have proved extremely powerful in identifying genes that promote tumor immune evasion or sensitize tumor cells to destruction by the immune system. These large-scale efforts have brought to light decades worth of fundamental immunology and have uncovered the key immune-evasion pathways subverted in cancers in an acquired manner in patients receiving immune-modulatory therapies. The comprehensive discovery of the main pathways involved in immune evasion has spurred the development and application of novel immune therapies to target this process. Although successful, conventional CRISPR screening approaches are hampered by a number of limitations, which obfuscate a complete understanding of the precise molecular regulation of immune evasion in cancer. Here, we provide a perspective on screening approaches to interrogate tumor-lymphocyte interactions and their limitations, and discuss further development of technologies to improve such approaches and discovery capability.

In vivo genome-wide CRISPR screening identifies CITED2 as a driver of prostate cancer bone metastasis

Most cancer deaths are due to metastatic dissemination to distant organs. Bone is the most frequently affected organ in metastatic prostate cancer and a major cause of prostate cancer deaths. Yet, our partial understanding of the molecular factors that drive bone metastasis has been a limiting factor for developing preventative and therapeutic strategies to improve patient survival and well-being. Although recent studies have uncovered molecular alterations that occur in prostate cancer metastasis, their functional relevance for bone metastasis is not well understood. Using genome-wide CRISPR activation and inhibition screens we have identified multiple drivers and suppressors of prostate cancer metastasis. Through functional validation, including an innovative organ-on-a-chip invasion platform for studying bone tropism, our study identifies the transcriptional modulator CITED2 as a novel driver of prostate cancer bone metastasis and uncovers multiple new potential molecular targets for bone metastatic disease.

The mTORC2 signaling network: targets and cross-talks

The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.

Uncovering hidden cancer self-dependencies through analysis of shRNA-level dependency scores

Large-scale short hairpin RNA (shRNA) screens on well-characterized human cancer cell lines have been widely used to identify novel cancer dependencies. However, the off-target effects of shRNA reagents pose a significant challenge in the analysis of these screens. To mitigate these off-target effects, various approaches have been proposed that aggregate different shRNA viability scores targeting a gene into a single gene-level viability score. Most computational methods for discovering cancer dependencies rely on these gene-level scores. In this paper, we propose a computational method, named NBDep, to find cancer self-dependencies by directly analyzing shRNA-level dependency scores instead of gene-level scores. The NBDep algorithm begins by removing known batch effects of the shRNAs and selecting a subset of concordant shRNAs for each gene. It then uses negative binomial random effects models to statistically assess the dependency between genetic alterations and the viabilities of cell lines by incorporating all shRNA dependency scores of each gene into the model. We applied NBDep to the shRNA dependency scores available at Project DRIVE, which covers 26 different types of cancer. The proposed method identified more well-known and putative cancer genes compared to alternative gene-level approaches in pan-cancer and cancer-specific analyses. Additionally, we demonstrated that NBDep controls type-I error and outperforms statistical tests based on gene-level scores in simulation studies.

Preclinical Anticipation of On- and Off-Target Resistance Mechanisms to Anti-Cancer Drugs: A Systematic Review

The advent of targeted therapies has led to tremendous improvements in treatment options and their outcomes in the field of oncology. Yet, many cancers outsmart precision drugs by developing on-target or off-target resistance mechanisms. Gaining the ability to resist treatment is the rule rather than the exception in tumors, and it remains a major healthcare challenge to achieve long-lasting remission in most cancer patients. Here, we discuss emerging strategies that take advantage of innovative high-throughput screening technologies to anticipate on- and off-target resistance mechanisms before they occur in treated cancer patients. We divide the methods into non-systematic approaches, such as random mutagenesis or long-term drug treatment, and systematic approaches, relying on the clustered regularly interspaced short palindromic repeats (CRISPR) system, saturated mutagenesis, or computational methods. All these new developments, especially genome-wide CRISPR-based screening platforms, have significantly accelerated the processes for identification of the mechanisms responsible for cancer drug resistance and opened up new avenues for future treatments.

Verteporfin Suppresses YAP-Induced Glycolysis in Breast Cancer Cells

OBJECTIVE

The inhibition of the Hippo pathway through targeting the Yes-associated protein (YAP) presents a novel and promising approach for treating tumors. However, the efficacy of YAP inhibitors in the context of breast cancer (BC) remains incompletely understood. Here, we aimed to investigate the involvement of YAP in BC's metabolic reprogramming and reveal the potential underlying mechanisms. To this end, we assessed the function of verteporfin (VP), a YAP-TEAD complex inhibitor, on the glycolytic activity of BC cells.

METHODS

We evaluated the expression of YAP by utilizing immunohistochemistry (IHC) in BC patients who have undergone 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) prior to biopsy/surgery. We employed RNA immunoprecipitation (RIP) and fluorescent in situ hybridization (FISH) assays to assess the interaction between YAP mRNA and human antigen R (HuR) in BC cells. The biological importance of YAP in the metabolism and malignancy of BC was evaluated in vitro. Finally, the effect of VP on glycolysis was determined by using 18F-FDG uptake, glucose consumption, and lactate production assays.

RESULTS

Our studies revealed that high expression of YAP was positively correlated with the maximum uptake value (SUVmax) determined by 18F-FDG PET/CT imaging in BC samples. Inhibition of YAP activity suppressed glycolysis in BC. The mechanism underlying this phenomenon could be the binding of YAP to HuR, which promotes glycolysis in BC cells. Treatment with VP effectively suppressed glycolysis induced by YAP overexpression in BC cells.

CONCLUSION

VP exhibited anti-glycolytic effect on BC cells, indicating its therapeutic value as an FDA-approved drug.

Clonal dynamics limits detection of selection in tumour xenograft CRISPR/Cas9 screens

Transplantable in vivo CRISPR/Cas9 knockout screens, in which cells are edited in vitro and inoculated into mice to form tumours, allow evaluation of gene function in a cancer model that incorporates the multicellular interactions of the tumour microenvironment. To improve our understanding of the key parameters for success with this method, we investigated the choice of cell line, mouse host, tumour harvesting timepoint and guide RNA (gRNA) library size. We found that high gRNA (80-95%) representation was maintained in a HCT116 subline transduced with the GeCKOv2 whole-genome gRNA library and transplanted into NSG mice when tumours were harvested at early (14 d) but not late time points (38-43 d). The decreased representation in older tumours was accompanied by large increases in variance in gRNA read counts, with notable expansion of a small number of random clones in each sample. The variable clonal dynamics resulted in a high level of 'noise' that limited the detection of gRNA-based selection. Using simulated datasets derived from our experimental data, we show that considerable reductions in count variance would be achieved with smaller library sizes. Based on our findings, we suggest a pathway to rationally design adequately powered in vivo CRISPR screens for successful evaluation of gene function.

New Insights into YAP/TAZ-TEAD-Mediated Gene Regulation and Biological Processes in Cancer

The Hippo pathway is conserved across species. Key mammalian Hippo pathway kinases, including MST1/2 and LATS1/2, inhibit cellular growth by inactivating the TEAD coactivators, YAP, and TAZ. Extensive research has illuminated the roles of Hippo signaling in cancer, development, and regeneration. Notably, dysregulation of Hippo pathway components not only contributes to tumor growth and metastasis, but also renders tumors resistant to therapies. This review delves into recent research on YAP/TAZ-TEAD-mediated gene regulation and biological processes in cancer. We focus on several key areas: newly identified molecular patterns of YAP/TAZ activation, emerging mechanisms that contribute to metastasis and cancer therapy resistance, unexpected roles in tumor suppression, and advances in therapeutic strategies targeting this pathway. Moreover, we provide an updated view of YAP/TAZ's biological functions, discuss ongoing controversies, and offer perspectives on specific debated topics in this rapidly evolving field.

Regulation of the Hippo/YAP axis by CXCR7 in the tumorigenesis of gastric cancer

BACKGROUND

The Hippo pathway is crucial in organ size control and tumorigenesis. Dysregulation of the Hippo/YAP axis is commonly observed in gastric cancer, while effective therapeutic targets for the Hippo/YAP axis are lacking. Identification of reliable drug targets and the underlying mechanisms that could inhibit the activity of the Hippo/YAP axis and gastric cancer progression is urgently needed.

METHODS

We used several gastric cancer cell lines and xenograft models and performed immunoblotting, qPCR, and in vivo studies to investigate the function of CXCR7 in gastric cancer progression.

RESULTS

In our current study, we demonstrate that the membrane receptor CXCR7 (C-X-C chemokine receptor 7) is an important modulator of the Hippo/YAP axis. The activation of CXCR7 could stimulate gastric cancer cell progression through the Hippo/YAP axis in vitro and in vivo, while pharmaceutical inhibition of CXCR7 via ACT-1004-1239 could block tumorigenesis in gastric cancer. Molecular studies revealed that the activation of CXCR7 could dephosphorylate YAP and facilitate YAP nuclear accumulation and transcriptional activation in gastric cancer. CXCR7 functions via G-protein Gαq/11 and Rho GTPase to activate YAP activity. Interestingly, ChIP assays showed that YAP could bind to the promoter region of CXCR7 and facilitate its gene transcription, which indicates that CXCR7 is both the upstream signalling and downstream target of the Hippo/YAP axis in gastric cancer.

CONCLUSION

In general, we identified a novel positive feedback loop between CXCR7 and the Hippo/YAP axis, and blockade of CXCR7 could be a plausible strategy for gastric cancer.

Combined in vitro/in vivo genome-wide CRISPR screens in triple negative breast cancer identify cancer stemness regulators in paclitaxel resistance

Triple negative breast cancer (TNBC) is defined as lacking the expressions of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). TNBC patients exhibit relatively poor clinical outcomes due to lack of molecular markers for targeted therapies. As such chemotherapy often remains the only systemic treatment option for these patients. While chemotherapy can initially help shrink TNBC tumor size, patients eventually develop resistance to drug, leading to tumor recurrence. We report a combined in vitro/in vivo genome-wide CRISPR synthetic lethality screening approach in a relevant TNBC cell line model to identify several targets responsible for the chemotherapy drug, paclitaxel resistance. Computational analysis integrating in vitro and in vivo data identified a set of genes, for which specific loss-of-function deletion enhanced paclitaxel resistance in TNBC. We found that several of these genes (ATP8B3, FOXR2, FRG2, HIST1H4A) act as cancer stemness negative regulators. Finally, using in vivo orthotopic transplantation TNBC models we showed that FRG2 gene deletion reduced paclitaxel efficacy and promoted tumor metastasis, while increasing FRG2 expression by means of CRISPR activation efficiently sensitized TNBC tumors to paclitaxel treatment and inhibited their metastatic abilities. In summary, the combined in vitro/in vivo genome-wide CRISPR screening approach proved effective as a tool to identify novel regulators of paclitaxel resistance/sensitivity and highlight the FRG2 gene as a potential therapeutical target overcoming paclitaxel resistance in TNBC.

(Nano)platforms in breast cancer therapy: Drug/gene delivery, advanced nanocarriers and immunotherapy

Breast cancer is the most malignant tumor in women, and there is no absolute cure for it. Although treatment modalities including surgery, chemotherapy, and radiotherapy are utilized for breast cancer, it is still a life-threatening disease for humans. Nanomedicine has provided a new opportunity in breast cancer treatment, which is the focus of the current study. The nanocarriers deliver chemotherapeutic agents and natural products, both of which increase cytotoxicity against breast tumor cells and prevent the development of drug resistance. The efficacy of gene therapy is boosted by nanoparticles and the delivery of CRISPR/Cas9, Noncoding RNAs, and RNAi, promoting their potential for gene expression regulation. The drug and gene codelivery by nanoparticles can exert a synergistic impact on breast tumors and enhance cellular uptake via endocytosis. Nanostructures are able to induce photothermal and photodynamic therapy for breast tumor ablation via cell death induction. The nanoparticles can provide tumor microenvironment remodeling and repolarization of macrophages for antitumor immunity. The stimuli-responsive nanocarriers, including pH-, redox-, and light-sensitive, can mediate targeted suppression of breast tumors. Besides, nanoparticles can provide a diagnosis of breast cancer and detect biomarkers. Various kinds of nanoparticles have been employed for breast cancer therapy, including carbon-, lipid-, polymeric- and metal-based nanostructures, which are different in terms of biocompatibility and delivery efficiency.

CRISPR screening in hematology research: from bulk to single-cell level

The CRISPR genome editing technology has revolutionized the way gene function is studied. Genome editing can be achieved in single genes or for thousands of genes simultaneously in sensitive genetic screens. While conventional genetic screens are limited to bulk measurements of cell behavior, recent developments in single-cell technologies make it possible to combine CRISPR screening with single-cell profiling. In this way, cell behavior and gene expression can be monitored simultaneously, with the additional possibility of including data on chromatin accessibility and protein levels. Moreover, the availability of various Cas proteins leading to inactivation, activation, or other effects on gene function further broadens the scope of such screens. The integration of single-cell multi-omics approaches with CRISPR screening open the path to high-content information on the impact of genetic perturbations at single-cell resolution. Current limitations in cell throughput and data density need to be taken into consideration, but new technologies are rapidly evolving and are likely to easily overcome these limitations. In this review, we discuss the use of bulk CRISPR screening in hematology research, as well as the emergence of single-cell CRISPR screening and its added value to the field.

RNF40 epigenetically modulates glycolysis to support the aggressiveness of basal-like breast cancer

Triple-negative breast cancer (TNBC) is the most difficult breast cancer subtype to treat due to the lack of targeted therapies. Cancer stem cells (CSCs) are strongly enriched in TNBC lesions and are responsible for the rapid development of chemotherapy resistance and metastasis. Ubiquitin-based epigenetic circuits are heavily exploited by CSCs to regulate gene transcription and ultimately sustain their aggressive behavior. Therefore, therapeutic targeting of these ubiquitin-driven dependencies may reprogram the transcription of CSC and render them more sensitive to standard therapies. In this work, we identified the Ring Finger Protein 40 (RNF40) monoubiquitinating histone 2B at lysine 120 (H2Bub1) as an indispensable E3 ligase for sustaining the stem-cell-like features of the growing mammary gland. In addition, we found that the RNF40/H2Bub1-axis promotes the CSC properties and drug-tolerant state by supporting the glycolytic program and promoting pro-tumorigenic YAP1-signaling in TNBC. Collectively, this study unveils a novel tumor-supportive role of RNF40 and underpins its high therapeutic value to combat the malignant behavior of TNBC.

Applications of CRISPR Technology to Breast Cancer and Triple Negative Breast Cancer Research

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has transformed oncology research in many ways. Breast cancer is the most prevalent malignancy globally and triple negative breast cancer (TNBC) is one of the most aggressive subtypes with numerous challenges still to be faced. In this work, we have explained what CRISPR consists of and listed its applications in breast cancer while focusing on TNBC research. These are disease modelling, the search for novel genes involved in tumour progression, sensitivity to drugs and immunotherapy response, tumour fitness, diagnosis, and treatment. Additionally, we have listed the current delivery methods employed for the delivery of CRISPR systems in vivo. Lastly, we have highlighted the limitations that CRISPR technology is subject to and the future directions that we envisage. Overall, we have provided a round summary of the aspects concerning CRISPR in breast cancer/TNBC research.

PLAGL2 promotes bladder cancer progression via RACGAP1/RhoA GTPase/YAP1 signaling

PLAGL2 is upregulated in various tumors, including bladder cancer (BCa). However, the mechanisms underlying the tumorigenic effects of PLAGL2 in BCa remain unclear. In our study, we proved that PLAGL2 was overexpressed in BCa tissues and correlated with decreased survival. Functionally, PLAGL2 deficiency significantly suppressed the proliferation and metastasis of BCa cells in vitro and in vivo. RNA sequencing, qRT‒PCR, immunoblotting, immunofluorescence staining, luciferase reporter, and ChIP assays revealed that overexpressed PLAGL2 disrupted the Hippo pathway and increased YAP1/TAZ activity by transactivating RACGAP1. Further investigations demonstrated that PLAGL2 activated YAP1/TAZ signaling via RACGAP1-mediated RhoA activation. Importantly, the RhoA inhibitor simvastatin or the YAP1/TAZ inhibitor verteporfin abrogated the proproliferative and prometastatic effects of BCa enhanced by PLAGL2. These findings suggest that PLAGL2 promotes BCa progression via RACGAP1/RhoA GTPase/YAP1 signaling. Hence, the core nodes of signaling may be promising therapeutic targets for BCa.

CRISPR/Cas9 as a therapeutic tool for triple negative breast cancer: from bench to clinics

Clustered regularly interspaced short palindromic repeats (CRISPR) is a third-generation genome editing method that has revolutionized the world with its high throughput results. It has been used in the treatment of various biological diseases and infections. Various bacteria and other prokaryotes such as archaea also have CRISPR/Cas9 systems to guard themselves against bacteriophage. Reportedly, CRISPR/Cas9-based strategy may inhibit the growth and development of triple-negative breast cancer (TNBC) via targeting the potentially altered resistance genes, transcription, and epigenetic regulation. These therapeutic activities could help with the complex issues such as drug resistance which is observed even in TNBC. Currently, various methods have been utilized for the delivery of CRISPR/Cas9 into the targeted cell such as physical (microinjection, electroporation, and hydrodynamic mode), viral (adeno-associated virus and lentivirus), and non-viral (liposomes and lipid nano-particles). Although different models have been developed to investigate the molecular causes of TNBC, but the lack of sensitive and targeted delivery methods for in-vivo genome editing tools limits their clinical application. Therefore, based on the available evidences, this review comprehensively highlighted the advancement, challenges limitations, and prospects of CRISPR/Cas9 for the treatment of TNBC. We also underscored how integrating artificial intelligence and machine learning could improve CRISPR/Cas9 strategies in TNBC therapy.

A Near-Infrared-II Fluorescent Nanocatalyst for Enhanced CAR T Cell Therapy against Solid Tumor by Immune Reprogramming

Chimeric antigen receptor (CAR) T cell therapy holds great promise in the treatment of hematological malignancies but performs poorly in solid tumors due to the tumor immunosuppressive microenvironment. Herein, a multifunctional nanocatalyst (APHA@CM) was prepared by encapsulating horseradish peroxidase (HRP)-loaded Au/polydopamine nanoparticles (Au/PDA NPs) and Ag₂S quantum dots with CAR T cell membranes to improve the CAR T cell therapy in solid tumors. The APHA@CM has excellent multimodal imaging capability to precisely guide the scope and time window for nanocatalyst-induced tumor microenvironment regulation and CAR T cell therapy. The oxidase-like activity of Au NPs inhibited the glycolytic metabolism of tumor cells, reducing lactate efflux, reprogramming tumor immunosuppression, and ultimately increasing CAR T cell activation within the tumors. Additionally, the hypoxia environment of tumors could be relieved by HRP to enhance the Au/PDA NPs-induced synergistic sonodynamic/photothermal therapy (SDT/PTT), thereby promoting the immunogenic cell death of NALM 6 cells and enhancing CAR T cell-mediated immune microenvironment reprogramming. When this strategy was utilized to treat NALM 6 solid tumors, it not only completely eliminated tumors but also formed a long-term immune memory effect to inhibit tumor metastasis and recurrence. This work offers a strategy for CAR T cell therapy in solid tumor.

MPFFPSDC: A multi-pooling feature fusion model for predicting synergistic drug combinations

Drug combination therapies are common practice in the treatment of cancer, but not all combinations result in synergy. As traditional screening approaches are restricted in their ability to uncover synergistic drug combinations, computer-aided medicine is becoming a increasingly prevalent in this field. In this work, a predictive model of potential interactions between drugs named MPFFPSDC is presented, which can maintain the symmetry of drug inputs and eliminate inconsistencies in predictive results caused by different drug inputting sequences or positions. The experimental results show that MPFFPSDC outperforms comparative models in major performance indicators and exhibits better generalization for independent data. Furthermore, the case study demonstrates that our model can capture molecular substructures that contribute to the synergistic effect of two drugs. These results indicate that MPFFPSDC not only offers strong predictive performance, but also has good model interpretability that may provide new insights for the study of drug interaction mechanisms and the development of new drugs.

A review on CRISPR/Cas: a versatile tool for cancer screening, diagnosis, and clinic treatment

Cancer is one of the leading causes of death worldwide and it has the trend of increase incidence. However, in the past decades, as quickly developed new technologies and modified old techniques for cancer screening, diagnosis, and treatment, the cancer-caused mortality rates dropped quickly, and the survival times of cancer patients are enhanced. However, the current death rate is still about 50% and the survival patients always suffer from the side effect of current cancer treatments. Recently developed Nobel Prize-winning CRISPR/Cas technology provides new hope on cancer screening, early diagnosis, and clinic treatment as well as new drug development. Currently, four major CRISPR/Cas9-derived genome editors, CRISPR/Cas9 nucleotide sequence editor, CRISPR/Cas base editor (BE), CRISPR prime editor (PE), and CRISPR interference (CRISPRi) (including both CRISPRa and CRISPRr), were well developed and used to various research and applications, including cancer biology study and cancer screening, diagnosis, and treatment. Additionally, CRISPR/Cas12 and CRISPR/Cas13 genome editors were also widely used in cancer-related basic and applied research as well as treatment. Cancer-associated SNPs and genetic mutations as well as both oncogenes and tumor suppressor genes are perfect targets for CRISPR/Cas-based gene therapy for cancer treatment. CRISPR/Cas is also employed to modify and generate new Chimeric antigen receptor (CAR) T-cells for improving its safety, efficiency, and longer-time last for treating various cancers. Currently, there are many clinic trails of CRISPR-based gene therapy for cancer treatments. Although all CRISPR/Cas-derived genome and epigenome tools are promising methods for cancer biology study and treatment, the efficiency and long term-safety are still the major concerns for CRISPR-based gene therapy. Developing new CRISPR/Cas delivery methods and reducing the potential side effects, including off-target impacts, will enhance CRISPR/Cas application in cancer-related research, diagnosis, and therapeutical treatment.

Rab7a-mTORC1 signaling-mediated cholesterol trafficking from the lysosome to mitochondria ameliorates hepatic lipotoxicity induced by aflatoxin B1 exposure

Aflatoxin B1 (AFB1) is a common contaminant in many foodstuffs and is considered a public health concern worldwide due to its hepatotoxicity caused by lipid metabolism disorders. However, the molecular mechanism underlying AFB1-induced lipotoxicity-dependent liver injury via regulating cholesterol metabolism remains unclear. We established a cholesterol trafficking disorder-mediated hepatic lipotoxicity model with AFB1 mixture exposure in vitro (HepaRG and HepG2 cells, 1.6 μM for 36 h) and in vivo (C57BL/6 mice, 3 mg kg^-1, i.g., every other day for 6 weeks). In vitro, the interaction between lysosomal Niemann-Pick type C1 (NPC1) protein and mitochondrial translocator protein (TSPO) regulated lipotoxicity induced by AFB1 mixture exposure, including lysosomal membrane permeabilization and mitochondria-dependent necroptosis. Moreover, the downregulation of lysosomal Ras-associated protein 7a (Rab7a) enhanced the mammalian target of rapamycin complex 1 (mTORC1)-mediated disorders of cholesterol trafficking from the lysosome to mitochondria. Furthermore, cholesterol trafficking disorder-mediated hepatic lipotoxicity induced by the low-dose level of AFB1 exposure was relieved by genetic or pharmaceutic activation of Rab7a to inhibit mTORC1 in vitro and ex vivo. In vivo, mTORC1 inhibitor (Torin1, 4 mg kg^-1, i.p., every other day for 3 weeks) alleviated the cholesterol trafficking disorder-mediated hepatic lipotoxicity via upregulating the molecular machinery of lysosomes and mitochondria contact mediated by NPC1 and TSPO interaction in the low dose of AFB1 exposure. Altogether, our data suggested a novel mechanism that lysosomal Rab7a-mTORC1 signaling determined the cholesterol trafficking regulated by NPC1-TSPO from the lysosome to mitochondria, which promoted hepatic lipotoxicity via lysosomal quality control and mitochondria-dependent necroptosis signaling pathways in chemical mixture exposure.

CRISPR/Cas genome editing in triple negative breast cancer: Current situation and future directions

Triple negative breast cancer (TNBC) has been well-known to be closely associated with the abnormal expression of both oncogenes and tumor suppressors. Although several pathogenic mutations in TNBC have been identified, the current therapeutic strategy is usually aimed at symptom relief rather than correcting mutations in the DNA sequence. Of note, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) has been gradually regarded as a breakthrough gene-editing tool with potential therapeutic applications in human cancers, including TNBC. Thus, in this review, we focus on summarizing the molecular subtypes of TNBC, as well as the CRISPR system and its potential applications in TNBC treatment. Moreover, we further discuss several emerging strategies for utilizing the CRISPR/Cas system to aid in the precise diagnosis of TNBC, as well as the limitations of the CRISPR/Cas system. Taken together, these findings would demonstrate that CRISPR/Cas system is not only an effective genome editing tool in TNBC, but a promising strategy for the future therapeutic purposes.

Wdr59 promotes or inhibits TORC1 activity depending on cellular context

Target of Rapamycin Complex I (TORC1) is a central regulator of metabolism in eukaryotes that responds to a wide array of negative and positive inputs. The GTPase-activating protein toward Rags (GATOR) signaling pathway acts upstream of TORC1 and is comprised of two subcomplexes. The trimeric GATOR1 complex inhibits TORC1 activity in response to amino acid limitation by serving as a GTPase-activating protein (GAP) for the TORC1 activator RagA/B, a component of the lysosomally located Rag GTPase. The multi-protein GATOR2 complex inhibits the activity of GATOR1 and thus promotes TORC1 activation. Here we report that Wdr59, originally assigned to the GATOR2 complex based on studies performed in tissue culture cells, unexpectedly has a dual function in TORC1 regulation in Drosophila. We find that in the ovary and the eye imaginal disc brain complex, Wdr59 inhibits TORC1 activity by opposing the GATOR2-dependent inhibition of GATOR1. Conversely, in the Drosophila fat body, Wdr59 promotes the accumulation of the GATOR2 component Mio and is required for TORC1 activation. Similarly, in mammalian HeLa cells, Wdr59 prevents the proteolytic destruction of GATOR2 proteins Mio and Wdr24. Consistent with the reduced levels of the TORC1-activating GATOR2 complex, Wdr59KOs HeLa cells have reduced TORC1 activity which is restored along with GATOR2 protein levels upon proteasome inhibition. Taken together, our data support the model that the Wdr59 component of the GATOR2 complex functions to promote or inhibit TORC1 activity depending on cellular context.

ATM inhibition drives metabolic adaptation via induction of macropinocytosis

Macropinocytosis is a nonspecific endocytic process that may enhance cancer cell survival under nutrient-poor conditions. Ataxia-Telangiectasia mutated (ATM) is a tumor suppressor that has been previously shown to play a role in cellular metabolic reprogramming. We report that the suppression of ATM increases macropinocytosis to promote cancer cell survival in nutrient-poor conditions. Combined inhibition of ATM and macropinocytosis suppressed proliferation and induced cell death both in vitro and in vivo. Supplementation of ATM-inhibited cells with amino acids, branched-chain amino acids (BCAAs) in particular, abrogated macropinocytosis. Analysis of ATM-inhibited cells in vitro demonstrated increased BCAA uptake, and metabolomics of ascites and interstitial fluid from tumors indicated decreased BCAAs in the microenvironment of ATM-inhibited tumors. These data reveal a novel basis of ATM-mediated tumor suppression whereby loss of ATM stimulates protumorigenic uptake of nutrients in part via macropinocytosis to promote cancer cell survival and reveal a potential metabolic vulnerability of ATM-inhibited cells.

RNF31 represses cell progression and immune evasion via YAP/PD-L1 suppression in triple negative breast Cancer

BACKGROUND

Recently genome-based studies revealed that the abnormality of Hippo signaling is pervasive in TNBC and played important role in cancer progression. RING finger protein 31 (RNF31) comes to RING family E3 ubiquitin ligase. Our previously published studies have revealed RNF31 is elevated in ER positive breast cancer via activating estrogen signaling and suppressing P53 pathway.

METHODS

We used several TNBC cell lines and xenograft models and performed immuno-blots, QPCR, in vivo studies to investigate the function of RNF31 in TNBC progression.

RESULT

Here, we demonstrate that RNF31 plays tumor suppressive function in triple negative breast cancer (TNBC). RNF31 depletion increased TNBC cell proliferation and migration in vitro and in vitro. RNF31 depletion in TNBC coupled with global genomic expression profiling indicated Hippo signaling could be the potential target for RNF31 to exert its function. Further data showed that RNF31 depletion could increase the level of YAP protein, and Hippo signaling target genes expression in several TNBC cell lines, while clinical data illustrated that RNF31 expression correlated with longer relapse-free survival in TNBC patients and reversely correlated with YAP protein level. The molecular biology assays implicated that RNF31 could associate with YAP protein, facilitate YAP poly-ubiquitination and degradation at YAP K76 sites. Interestingly, RNF31 could also repress PDL1 expression and sensitive TNBC immunotherapy via inhibiting Hippo/YAP/PDL1 axis.

CONCLUSIONS

Our study revealed the multi-faced function of RNF31 in different subtypes of breast malignancies, while activation RNF31 could be a plausible strategy for TNBC therapeutics.

A CRISPR Path to Finding Vulnerabilities and Solving Drug Resistance: Targeting the Diverse Cancer Landscape and Its Ecosystem

Cancer is the second leading cause of death globally, with therapeutic resistance being a major cause of treatment failure in the clinic. The dynamic signaling that occurs between tumor cells and the diverse cells of the surrounding tumor microenvironment actively promotes disease progression and therapeutic resistance. Improving the understanding of how tumors evolve following therapy and the molecular mechanisms underpinning de novo or acquired resistance is thus critical for the identification of new targets and for the subsequent development of more effective combination regimens. Simultaneously targeting multiple hallmark capabilities of cancer to circumvent adaptive or evasive resistance may lead to significantly improved treatment response in the clinic. Here, the latest applications of functional genomics tools, such as clustered regularly interspaced short palindromic repeats (CRISPR) editing, to characterize the dynamic cancer resistance mechanisms, from improving the understanding of resistance to classical chemotherapeutics, to deciphering unique mechanisms that regulate tumor responses to new targeted agents and immunotherapies, are discussed. Potential avenues of future research in combating therapeutic resistance, the contribution of tumor-stroma signaling in this setting, and how advanced functional genomics tools can help streamline the identification of key molecular determinants of drug response are explored.

Integration of CRISPR/Cas9 with artificial intelligence for improved cancer therapeutics

Gene editing has great potential in treating diseases caused by well-characterized molecular alterations. The introduction of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)–based gene-editing tools has substantially improved the precision and efficiency of gene editing. The CRISPR/Cas9 system offers several advantages over the existing gene-editing approaches, such as its ability to target practically any genomic sequence, enabling the rapid development and deployment of novel CRISPR-mediated knock-out/knock-in methods. CRISPR/Cas9 has been widely used to develop cancer models, validate essential genes as druggable targets, study drug-resistance mechanisms, explore gene non-coding areas, and develop biomarkers. CRISPR gene editing can create more-effective chimeric antigen receptor (CAR)-T cells that are durable, cost-effective, and more readily available. However, further research is needed to define the CRISPR/Cas9 system’s pros and cons, establish best practices, and determine social and ethical implications. This review summarizes recent CRISPR/Cas9 developments, particularly in cancer research and immunotherapy, and the potential of CRISPR/Cas9-based screening in developing cancer precision medicine and engineering models for targeted cancer therapy, highlighting the existing challenges and future directions. Lastly, we highlight the role of artificial intelligence in refining the CRISPR system's on-target and off-target effects, a critical factor for the broader application in cancer therapeutics.

The Hippo signalling pathway and its implications in human health and diseases

As an evolutionarily conserved signalling network, the Hippo pathway plays a crucial role in the regulation of numerous biological processes. Thus, substantial efforts have been made to understand the upstream signals that influence the activity of the Hippo pathway, as well as its physiological functions, such as cell proliferation and differentiation, organ growth, embryogenesis, and tissue regeneration/wound healing. However, dysregulation of the Hippo pathway can cause a variety of diseases, including cancer, eye diseases, cardiac diseases, pulmonary diseases, renal diseases, hepatic diseases, and immune dysfunction. Therefore, therapeutic strategies that target dysregulated Hippo components might be promising approaches for the treatment of a wide spectrum of diseases. Here, we review the key components and upstream signals of the Hippo pathway, as well as the critical physiological functions controlled by the Hippo pathway. Additionally, diseases associated with alterations in the Hippo pathway and potential therapies targeting Hippo components will be discussed.

Exploring the genetic space of the DNA damage response for cancer therapy through CRISPR-based screens

The concepts of synthetic lethality and viability have emerged as powerful approaches to identify vulnerabilities and resistances within the DNA damage response for the treatment of cancer. Historically, interactions between two genes have had a longstanding presence in genetics and have been identified through forward genetic screens that rely on the molecular basis of the characterized phenotypes, typically caused by mutations in single genes. While such complex genetic interactions between genes have been studied extensively in model organisms, they have only recently been prioritized as therapeutic strategies due to technological advancements in genetic screens. Here, we discuss synthetic lethal and viable interactions within the DNA damage response and present how CRISPR-based genetic screens and chemical compounds have allowed for the systematic identification and targeting of such interactions for the treatment of cancer.

Nanomaterial-assisted CRISPR gene-engineering - A hallmark for triple-negative breast cancer therapeutics advancement

Triple-negative breast cancer (TNBC) is the most violent class of tumor and accounts for 20–24% of total breast carcinoma, in which frequently rare mutation occurs in high frequency. The poor prognosis, recurrence, and metastasis in the brain, heart, liver and lungs decline the lifespan of patients by about 21 months, emphasizing the need for advanced treatment. Recently, the adaptive immunity mechanism of archaea and bacteria, called clustered regularly interspaced short palindromic repeats (CRISPR) combined with nanotechnology, has been utilized as a potent gene manipulating tool with an extensive clinical application in cancer genomics due to its easeful usage and cost-effectiveness. However, CRISPR/Cas are arguably the efficient technology that can be made efficient via organic material-assisted approaches. Despite the efficacy of the CRISPR/Cas@nano complex, problems regarding successful delivery, biodegradability, and toxicity remain to render its medical implications. Therefore, this review is different in focus from past reviews by (i) detailing all possible genetic mechanisms of TNBC occurrence; (ii) available treatments and gene therapies for TNBC; (iii) overview of the delivery system and utilization of CRISPR-nano complex in TNBC, and (iv) recent advances and related toxicity of CRISPR-nano complex towards clinical trials for TNBC.

In Situ Transformable Supramolecular Nanomedicine Targeted Activating Hippo Pathway for Triple-Negative Breast Cancer Growth and Metastasis Inhibition

As it is closely associated with tumor proliferation, metastasis, and the immunosuppressive microenvironment, the dysfunctional Hippo pathway has become an extremely attractive target for treating multiple cancers. However, to date, the corresponding chemotherapeutic nanomedicines have not been developed. Herein, a supramolecular self-delivery nanomedicine with in situ transforming capacity was tailor-constructed for Hippo-pathway restoration, and its inhibitory effect against tumor growth and metastasis was investigated in a highly aggressive triple-negative breast cancer (TNBC) model. Stimulated by overexpressed glutathione (GSH) and esterase in cancer cells, the self-assembled nanomedicine transformed from inactive nanospheres to active nanofibers conjugating tyrosvaline and spatiotemporally synchronously released the covalently linked flufenamic acid in situ, together activating the maladjusted Hippo pathway by simultaneously acting on different targets upstream and downstream. The transcriptional expression of Yes-associated protein (YAP) and related growth-promoted genes were significantly reduced, finally significantly repressing the proliferation and metastasis of cancer cells. Additionally, the Hippo-pathway restoration showed an excellent radiosensitization effect, making the targeted therapy combined with radiotherapy display a prominent synergistic in vivo anticancer effect against TNBC. This work reports a specifically designed smart nanomedicine to restore the function of the Hippo pathway and sensitize radiotherapy, providing an attractive paradigm for targeted drug delivery and cancer combination therapy.

Advances of Epigenetic Biomarkers and Epigenome Editing for Early Diagnosis in Breast Cancer

Epigenetic modifications are known to regulate cell phenotype during cancer progression, including breast cancer. Unlike genetic alterations, changes in the epigenome are reversible, thus potentially reversed by epi-drugs. Breast cancer, the most common cause of cancer death worldwide in women, encompasses multiple histopathological and molecular subtypes. Several lines of evidence demonstrated distortion of the epigenetic landscape in breast cancer. Interestingly, mammary cells isolated from breast cancer patients and cultured ex vivo maintained the tumorigenic phenotype and exhibited aberrant epigenetic modifications. Recent studies indicated that the therapeutic efficiency for breast cancer regimens has increased over time, resulting in reduced mortality. Future medical treatment for breast cancer patients, however, will likely depend upon a better understanding of epigenetic modifications. The present review aims to outline different epigenetic mechanisms including DNA methylation, histone modifications, and ncRNAs with their impact on breast cancer, as well as to discuss studies highlighting the central role of epigenetic mechanisms in breast cancer pathogenesis. We propose new research areas that may facilitate locus-specific epigenome editing as breast cancer therapeutics.

The Role and Therapeutic Potential of Macropinocytosis in Cancer

Macropinocytosis, a unique endocytosis pathway characterized by nonspecific internalization, has a vital role in the uptake of extracellular substances and antigen presentation. It is known to have dual effects on cancer cells, depending on cancer type and certain microenvironmental conditions. It helps cancer cells survive in nutrient-deficient environments, enhances resistance to anticancer drugs, and promotes invasion and metastasis. Conversely, overexpression of the RAS gene alongside drug treatment can lead to methuosis, a novel mode of cell death. The survival and proliferation of cancer cells is closely related to macropinocytosis in the tumor microenvironment (TME), but identifying how these cells interface with the TME is crucial for creating drugs that can limit cancer progression and metastasis. Substantial progress has been made in recent years on designing anticancer therapies that utilize the effects of macropinocytosis. Both the induction and inhibition of macropinocytosis are useful strategies for combating cancer cells. This article systematically reviews the general mechanisms of macropinocytosis, its specific functions in tumor cells, its occurrence in nontumor cells in the TME, and its application in tumor therapies. The aim is to elucidate the role and therapeutic potential of macropinocytosis in cancer treatment.

PI3K/AKT/mTOR-Targeted Therapy for Breast Cancer

Phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB/AKT) and mechanistic target of rapamycin (mTOR) (PAM) pathways play important roles in breast tumorigenesis and confer worse prognosis in breast cancer patients. The inhibitors targeting three key nodes of these pathways, PI3K, AKT and mTOR, are continuously developed. For breast cancer patients to truly benefit from PAM pathway inhibitors, it is necessary to clarify the frequency and mechanism of abnormal alterations in the PAM pathway in different breast cancer subtypes, and further explore reliable biomarkers to identify the appropriate population for precision therapy. Some PI3K and mTOR inhibitors have been approved by regulatory authorities for the treatment of specific breast cancer patient populations, and many new-generation PI3K/mTOR inhibitors and AKT isoform inhibitors have also been shown to have good prospects for cancer therapy. This review summarizes the changes in the PAM signaling pathway in different subtypes of breast cancer, and the latest research progress about the biomarkers and clinical application of PAM-targeted inhibitors.

CRISPR/Cas9 system in breast cancer therapy: advancement, limitations and future scope

Cancer is one of the major causes of mortality worldwide, therefore it is considered a major health concern. Breast cancer is the most frequent type of cancer which affects women on a global scale. Various current treatment strategies have been implicated for breast cancer therapy that includes surgical removal, radiation therapy, hormonal therapy, chemotherapy, and targeted biological therapy. However, constant effort is being made to introduce novel therapies with minimal toxicity. Gene therapy is one of the promising tools, to rectify defective genes and cure various cancers. In recent years, a novel genome engineering technology, namely the clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein-9 (Cas9) has emerged as a gene-editing tool and transformed genome-editing techniques in a wide range of biological domains including human cancer research and gene therapy. This could be attributed to its versatile characteristics such as high specificity, precision, time-saving and cost-effective methodologies with minimal risk. In the present review, we highlight the role of CRISPR/Cas9 as a targeted therapy to tackle drug resistance, improve immunotherapy for breast cancer.

In vivo genome-wide CRISPR screening in murine acute myeloid leukemia uncovers microenvironmental dependencies

In vivo CRISPR screens in AML define key interactors of the microenvironment, including integrins, immune modulators, and glycosylation.

Eight in vivo–specific hits are recurrently associated with adverse prognosis: BTBD6, FERMT3, ILK, SLC19A1, TAP2, TLN1, TPST2, and TRMT12.

Genome-wide CRISPR screens have been extremely useful in identifying therapeutic targets in diverse cancers by defining genes that are essential for malignant growth. However, most CRISPR screens were performed in vitro and thus cannot identify genes that are essential for interactions with the microenvironment in vivo. Here, we report genome-wide CRISPR screens in 2 in vivo murine models of acute myeloid leukemia (AML) driven by the KMT2A/MLLT3 fusion or by the constitutive coexpression of Hoxa9 and Meis1. Secondary validation using a focused library identified 72 genes specifically essential for leukemic growth in vivo, including components of the major histocompatibility complex class I complex, Cd47, complement receptor Cr1l, and the β-4-galactosylation pathway. Importantly, several of these in vivo–specific hits have a prognostic effect or are inferred to be master regulators of protein activity in human AML cases. For instance, we identified Fermt3, a master regulator of integrin signaling, as having in vivo–specific dependency with high prognostic relevance. Overall, we show an experimental and computational pipeline for genome-wide functional screens in vivo in AML and provide a genome-wide resource of essential drivers of leukemic growth in vivo.

CRISPR screening in cancer stem cells

Cancer stem cells (CSCs) are a subpopulation of tumor cells with self-renewal ability. Increasing evidence points to the critical roles of CSCs in tumorigenesis, metastasis, therapy resistance, and cancer relapse. As such, the elimination of CSCs improves cancer treatment outcomes. However, challenges remain due to limited understanding of the molecular mechanisms governing self-renewal and survival of CSCs. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 screening has been increasingly used to identify genetic determinants in cancers. In this primer, we discuss the progress made and emerging opportunities of coupling advanced CRISPR screening systems with CSC models to reveal the understudied vulnerabilities of CSCs.

CRISPR in cancer biology and therapy

Over the past decade, CRISPR has become as much a verb as it is an acronym, transforming biomedical research and providing entirely new approaches for dissecting all facets of cell biology. In cancer research, CRISPR and related tools have offered a window into previously intractable problems in our understanding of cancer genetics, the noncoding genome and tumour heterogeneity, and provided new insights into therapeutic vulnerabilities. Here, we review the progress made in the development of CRISPR systems as a tool to study cancer, and the emerging adaptation of these technologies to improve diagnosis and treatment.

CRISPR based therapeutics: a new paradigm in cancer precision medicine

Background

Clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein (Cas) systems are the latest addition to the plethora of gene-editing tools. These systems have been repurposed from their natural counterparts by means of both guide RNA and Cas nuclease engineering. These RNA-guided systems offer greater programmability and multiplexing capacity than previous generation gene editing tools based on zinc finger nucleases and transcription activator like effector nucleases. CRISPR-Cas systems show great promise for individualization of cancer precision medicine.

Main body

The biology of Cas nucleases and dead Cas based systems relevant for in vivo gene therapy applications has been discussed. The CRISPR knockout, CRISPR activation and CRISPR interference based genetic screens which offer opportunity to assess functions of thousands of genes in massively parallel assays have been also highlighted. Single and combinatorial gene knockout screens lead to identification of drug targets and synthetic lethal genetic interactions across different cancer phenotypes. There are different viral and non-viral (nanoformulation based) modalities that can carry CRISPR-Cas components to different target organs in vivo.

Conclusion

The latest developments in the field in terms of optimization of performance of the CRISPR-Cas elements should fuel greater application of the latter in the realm of precision medicine. Lastly, how the already available knowledge can help in furtherance of use of CRISPR based tools in personalized medicine has been discussed.

Novel sequential therapy with metformin enhances the effects of cisplatin in testicular germ cell tumours via YAP1 signalling

Background

Testicular germ cell tumours (TGCTs) are the most commonly diagnosed malignancy in young men. Although cisplatin has been shown to be effective to treat TGCT patients, long-term follow-up has shown that TGCT survivors who accepted cisplatin treatment suffered from a greater number of adverse reactions than patients who underwent orchiectomy alone. As metformin has shown an anticancer effect in various cancers, we investigated whether metformin could enhance the effects of cisplatin to treat TGCTs.

Methods

The anticancer effects of different treatment strategies consisting of metformin and cisplatin in TCam-2 and NTERA-2 cells were assessed in vitro and in vivo. First, we used a colony formation assay, CCK-8 and MTT assays to explore the viability of TGCT cells. Flow cytometry was used to assess the cell cycle and apoptosis of TGCTs. Then, Western blotting was used to detect the protein expression of TGCTs cells after different treatments. In addition, a xenograft model was used to investigate the effects of the different treatments on the proliferation of TGCT cells. Immunohistochemistry assays were performed to analyse the expression of related proteins in the tissues from the xenograft model.

Results

Metformin inhibited the proliferation of TCam-2 and NTERA-2 cells by arresting them in G1 phase, while metformin did not induce apoptosis in TGCT cells. Compared with cisplatin monotherapy, the CCK-8, MTT assay and colony formation assay showed that sequential treatment with metformin and cisplatin produced enhanced anticancer effects. Further study showed that metformin blocked the cells in G1 phase by inducing phosphorylated YAP1 and reducing the expression of cyclin D1, CDK6, CDK4 and RB, which enhanced the chemosensitivity of cisplatin and activated the expression of cleaved caspase 3 in TGCTs.

Conclusions

Our study discovers the important role of YAP1 in TGCTs and reports a new treatment strategy that employs the sequential administration of metformin and cisplatin, which can reduce the required cisplatin dose and enhance the sensitivity of TGCT cells to cisplatin. Therefore, this sequential treatment strategy may facilitate the development of basic and clinical research for anticancer therapies to treat TGCTs.