Cell polarity in development and cancer

Near-infrared lipid droplets polarity fluorescent probe for early diagnosis of nonalcoholic fatty liver disease

Nowadays, it has been proven that lipid droplets (LDs) not only maintain the fundamental cellular functions, but also play an essential role in the pathogenesis of numerous diseases. Non-alcoholic fatty liver disease (NAFLD) is among these diseases. In this work, we designed two polarity sensitive fluorescent probes TST and TSO with D-π-A-D structure by introducing different electron acceptor groups according to the low polarity of LDs. The experimental discovered that probe TST exhibited the characteristics of near-infrared emission, high selectivity towards polarity, large Stokes shift, rapid targeting ability of LDs, and robust wash-free biological imaging capability. Confocal images illustrated that probe TST has been successfully applied in monitoring LDs polarity during ferroptosis, as well as visualizing changes in LDs polarity at both tissue and organ levels in fatty liver conditions. With these exceptional properties, probe TST was anticipated to make further contributions to the field of LDs research.

Plakins are involved in the regulation of centrosome position in polarized epithelial cells

BACKGROUND INFORMATION

The control of epithelial cell polarity is key to their function. Its dysregulation is a major cause of tissue transformation. In polarized epithelial cells,the centrosome is off-centred toward the apical pole. This asymmetry determines the main orientation of the microtubule network and intra-cellular traffic. However, the mechanism regulating centrosome positioning at the apical pole of polarized epithelial cells is still poorly undertood.

RESULTS

In this study we used transcriptomic data from breast cancer cells to identify molecular changes associated with the different stages of tumour transformation. We correlated these changes with variations in centrosome position or with cell progression along the epithelial-to-mesenchymal transition (EMT), a process that involves centrosome repositioning. We found that low levels of epiplakin, desmoplakin and periplakin correlated with centrosome mispositioning in cells that had progressed through EMT or tissue transformation. We further tested the causal role of these plakins in the regulation of centrosome position by knocking down their expression in a non-tumorigenic breast epithelial cell line (MCF10A). The downregulation of periplakin reduced the length of intercellular junction, which was not affected by the downregulation of epiplakin or desmoplakin. However, down-regulating any of them disrupted centrosome polarisation towards the junction without affecting microtubule stability.

CONCLUSIONS

Altogether, these results demonstrated that epiplakin, desmoplakin and periplakin are involved in the maintenance of the peripheral position of the centrosome close to inter-cellular junctions. They also revealed that these plakins are downregulated during EMT and breast cancer progression, which are both associated with centrosome mispositioning.

SIGNIFICANCE

These results revealed that the down-regulation of plakins and the consequential centrosome mispositioning are key signatures of disorganised cytoskeleton networks, inter-cellular junction weakening, shape deregulation and the loss of polarity in breast cancer cells. These metrics could further be used as a new readouts for early phases of tumoral development.

Biosensors for Cancer Biomarkers Based on Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles (MSNs) exhibit highly beneficial characteristics for devising efficient biosensors for different analytes. Their unique properties, such as capabilities for stable covalent binding to recognition groups (e.g., antibodies or aptamers) and sensing surfaces, open a plethora of opportunities for biosensor construction. In addition, their structured porosity offers capabilities for entrapping signaling molecules (dyes or electroactive species), which could be released efficiently in response to a desired analyte for effective optical or electrochemical detection. This work offers an overview of recent research studies (in the last five years) that contain MSNs in their optical and electrochemical sensing platforms for the detection of cancer biomarkers, classified by cancer type. In addition, this study provides an overview of cancer biomarkers, as well as electrochemical and optical detection methods in general.

Recent Advances in Graphene Oxide-Based on Organoid Culture as Disease Model and Cell Behavior - A Systematic Literature Review

Due to their ability to replicate the in vivo microenvironment through cell interaction and induce cells to stimulate cell function, three-dimensional cell culture models can overcome the limitations of two-dimensional models. Organoids are 3D models that demonstrate the ability to replicate the natural structure of an organ. In most organoid tissue cultures, matrigel made of a mouse tumor extracellular matrix protein mixture is an essential ingredient. However, its tumor-derived origin, batch-to-batch variation, high cost, and safety concerns have limited the usefulness of organoid drug development and regenerative medicine. Its clinical application has also been hindered by the fact that organoid generation is dependent on the use of poorly defined matrices. Therefore, matrix optimization is a crucial step in developing organoid culture that introduces alternatives as different materials. Recently, a variety of substitute materials has reportedly replaced matrigel. The purpose of this study is to review the significance of the latest advances in materials for cell culture applications and how they enhance build network systems by generating proper cell behavior. Excellence in cell behavior is evaluated from their cell characteristics, cell proliferation, cell differentiation, and even gene expression. As a result, graphene oxide as a matrix optimization demonstrated high potency in developing organoid models. Graphene oxide can promote good cell behavior and is well known for having good biocompatibility. Hence, advances in matrix optimization of graphene oxide provide opportunities for the future development of advanced organoid models.

Integrated multi-omics analyses revealed the association between rheumatoid arthritis and colorectal cancer: MYO9A as a shared gene signature and an immune-related therapeutic target

BACKGROUND

Our study aims to explore the relationship, shared gene signature, and the underlying mechanisms that connect rheumatoid arthritis (RA) to colorectal cancer (CRC).

METHODS

Mendelian randomization (MR) analysis was conducted to assess the causality between RA and CRC. Summary statistic data-based Mendelian randomization (SMR) leveraging eQTL data was employed to identify the CRC-related causal genes. Integrated analyses of single-cell RNA sequencing and bulk RNA sequencing were employed to comprehensively investigate the shared gene signature and potential mechanisms underlying the pathogenesis of both RA and CRC. Predictive analysis of the shared hub gene in CRC immunotherapy response was performed. Pan-cancer analyses were conducted to explore the potential role of MYO9A in 33 types of human tumors.

RESULTS

MR analysis suggested that RA might be associated with a slight increased risk of CRC (Odds Ratio = 1.04, 95% Confidence Interval = 1.01-1.07, P = 0.005). SMR analysis combining transcriptome analyses identified MYO9A as a causal gene in CRC and a shared gene signature in both RA and CRC. MYO9A may contribute to tumor suppression, while downregulation of MYO9A may impact CRC tumorigenesis by disrupting epithelial polarity and architecture, resulting in a worse prognosis in CRC. Additionally, MYO9A shows promise as a powerful predictive biomarker for cancer prognosis and immunotherapy response in CRC. Pan-cancer analyses demonstrated MYO9A may have a protective role in the occurrence and progression of various human cancers.

CONCLUSION

RA might be associated with a slight increased risk of CRC. MYO9A is a shared gene signature and a potential immune-related therapeutic target for both CRC and RA. Targeting the MYO9A-mediated loss of polarity and epithelial architecture could be a novel therapeutic approach for CRC.

A D-π-A-type ratiometric fluorescent probe to detect polarity changes and inhibition effect during ferroptosis

To thoroughly understand ferroptosis's biological functions in living cells, it is crucial to investigate the polarity variations that occur during this unique Fe(II)-facilitated oxidative type of cell death. In this work, we report the development of a ratiometric probe (Po-P) to visualize the polarity changes in living cells and the inhibition effect during ferroptosis. The polarity-responsive fluorophore utilized by Po-P has a D-π-A-type structure. Based on theoretical calculations, ICT was proposed as the basis for Po-P's polarity-responsive mechanism. According to cell imaging results, Po-P had a desirable capacity for monitoring polarity fluctuations and erastin-induced ferroptosis. Furthermore, inhibition imaging revealed that dihydrolipoic acid (DHLA) could potentially prevent polarity changes that occur during erastin-induced ferroptosis, just as vitamin E (VE). We anticipate that the probe Po-P could be a valuable tool to quickly monitor polarity fluctuations and inhibition effects during ferroptosis and create new medications for treating disorders related to ferroptosis.

Water-Soluble Small Organic Fluorophores for Oncological Theragnostic Applications: Progress and Development

Cancer is one of the major noncommunicable diseases, responsible for millions of deaths every year worldwide. Though various cancer detection and treatment modalities are available today, many deaths occur owing to its late-stage detection and metastatic nature. Noninvasive detection using luminescence-based imaging tools is considered one of the promising techniques owing to its low cost, high sensitivity, and brightness. Moreover, these tools are unique and valuable as they can detect even the slightest changes in the cellular microenvironment. To achieve this, a fluorescent probe with strong tumor uptake and high spatial and temporal resolution, especially with high water solubility, is highly demanded. Recently, several water-soluble molecules with emission windows in the visible (400-700 nm), first near-infrared (NIR-I, 700-1000 nm), and second near-infrared (NIR-II, 1000-1700 nm) windows have been reported in literature. This review highlights recently reported water-soluble small organic fluorophores/dyes with applications in cancer diagnosis and therapeutics. We systematically highlight and describe the key concepts, structural classes of fluorophores, strategies for imparting water solubility, and applications in cancer therapy and diagnosis, i.e., theragnostics. We discuss examples of water-soluble fluorescent probes based on coumarin, xanthene, boron-dipyrromethene (BODIPY), and cyanine cores. Some other emerging classes of dyes based on carbocyclic and heterocyclic cores are also discussed. Besides, emerging molecular engineering methods to obtain such fluorophores are discussed. Finally, the opportunities and challenges in this research area are also delineated.

A novel fluorescent probe for visualizing viscosity changes in lipid droplets during chemotherapy-induced ferroptosis

BACKGROUND

Ferroptosis, as a novel form of cell death, is becoming one of the hot topics in cancer treatment research. It differs from necrosis and autophagy in that it involves the accumulation of lipid peroxides and is triggered by iron dependency. Recent studies have suggested that this mechanism may alter the viscosity or structure of lipid droplets (LDs). The relationship between LDs viscosity and ferroptosis remains an active area of research with limited reports at present. Additionally, there is a lack of effective anticancer drugs targeting the ferroptosis pathway to promote ferroptosis in tumour cells. Therefore, the development of tools to detect viscosity changes during ferroptosis and targeted therapeutic strategies is of great significance.

RESULTS

By coupling 1,3-indandione with naphthalimide, including decamethylamine as a LDs recognition group, we designed and synthesized an environmental fluorescent probe that induces intramolecular charge transfer (TICT) effects. Notably, the diffusion and transport of intracellular substances may be affected in highly viscous environments. Under such conditions, intracellular iron ions may accumulate, leading to peroxide production and cellular damage, which can trigger ferroptosis. Therefore, WD-1 achieved excellent in situ bioimaging of LDs targeting and its viscosity during ferroptosis in HeLa cells and zebrafish. Furthermore, it was observed that WD-1 effectively differentiated between malignant and normal cells during this process, highlighting its potential significance in distinguishing cellular states. In addition, we used the antitumour drug paclitaxel to study ferroptosis in cancer cells. These findings not only provide an excellent tool for the development of the ferroptosis response, but also are crucial for understanding the biological properties of LDs during the ferroptosis response.

SIGNIFICANCE AND NOVELTY

Based on a powerful tool of fluorescent probe with in vivo bioimaging, we developed WD-1 to track the impact of paclitaxel on the process of ferroptosis in living cells. Therefore, we preliminarily believe that paclitaxel may affect the occurrence of ferroptosis and control apoptosis in cancer cells. These findings not only serve as an exceptional tool for advancing our understanding of the ferroptosis response, but furthermore play a vital role in comprehending the biological characteristics of LDs in relation to ferroptosis.

RhoA downregulation in the murine intestinal epithelium results in chronic Wnt activation and increased tumorigenesis

Rho GTPases are molecular switches regulating multiple cellular processes. To investigate the role of RhoA in normal intestinal physiology, we used a conditional mouse model overexpressing a dominant negative RhoA mutant (RhoAT19N) in the intestinal epithelium. Although RhoA inhibition did not cause an overt phenotype, increased levels of nuclear β-catenin were observed in the small intestinal epithelium of RhoAT19N mice, and the overexpression of multiple Wnt target genes revealed a chronic activation of Wnt signaling. Elevated Wnt signaling in RhoAT19N mice and intestinal organoids did not affect the proliferation of intestinal epithelial cells but significantly interfered with their differentiation. Importantly, 17-month-old RhoAT19N mice showed a significant increase in the number of spontaneous intestinal tumors. Altogether, our results indicate that RhoA regulates the differentiation of intestinal epithelial cells and inhibits tumor initiation, likely through the control of Wnt signaling, a key regulator of proliferation and differentiation in the intestine.

Expanding the Chemical Space of Transforming Growth Factor-β (TGFβ) Receptor Type II Degraders with 3,4-Disubstituted Indole Derivatives

The TGFβ type II receptor (TβRII) is a central player in all TGFβ signaling downstream events, has been linked to cancer progression, and thus, has emerged as an auspicious anti-TGFβ strategy. Especially its targeted degradation presents an excellent goal for effective TGFβ pathway inhibition. Here, cellular structure-activity relationship (SAR) data from the TβRII degrader chemotype 1 was successfully transformed into predictive ligand-based pharmacophore models that allowed scaffold hopping. Two distinct 3,4-disubstituted indoles were identified from virtual screening: tetrahydro-4-oxo-indole 2 and indole-3-acetate 3. Design, synthesis, and screening of focused amide libraries confirmed 2r and 3n as potent TGFβ inhibitors. They were validated to fully recapitulate the ability of 1 to selectively degrade TβRII, without affecting TβRI. Consequently, 2r and 3n efficiently blocked endothelial-to-mesenchymal transition and cell migration in different cancer cell lines while not perturbing the microtubule network. Hence, 2 and 3 present novel TβRII degrader chemotypes that will (1) aid target deconvolution efforts and (2) accelerate proof-of-concept studies for small-molecule-driven TβRII degradation in vivo.

Inverted apicobasal polarity in health and disease

Apicobasal epithelial polarity controls the functional properties of most organs. Thus, there has been extensive research on the molecular intricacies governing the establishment and maintenance of cell polarity. Whereas loss of apicobasal polarity is a well-documented phenomenon associated with multiple diseases, less is known regarding another type of apicobasal polarity alteration - the inversion of polarity. In this Review, we provide a unifying definition of inverted polarity and discuss multiple scenarios in mammalian systems and human health and disease in which apical and basolateral membrane domains are interchanged. This includes mammalian embryo implantation, monogenic diseases and dissemination of cancer cell clusters. For each example, the functional consequences of polarity inversion are assessed, revealing shared outcomes, including modifications in immune surveillance, altered drug sensitivity and changes in adhesions to neighboring cells. Finally, we highlight the molecular alterations associated with inverted apicobasal polarity and provide a molecular framework to connect these changes with the core cell polarity machinery and to explain roles of polarity inversion in health and disease. Based on the current state of the field, failure to respond to extracellular matrix (ECM) cues, increased cellular contractility and membrane trafficking defects are likely to account for most cases of inverted apicobasal polarity.

Imaging and Analysis of Drosophila Neural Stem Cell Asymmetric Division

Cell division is a conserved process among eukaryotes. It is designed to segregate chromosomes into future daughter cells and involves a complex rearrangement of the cytoskeleton, including microtubules and actin filaments. An additional level of complexity is present in asymmetric dividing stem cells because cytoskeleton elements are also regulated by polarity cues. The neural stem cell system of the fruit fly represents a simple model to dissect the mechanisms that control cytoskeleton reorganization during asymmetric division. In this chapter, we propose to describe protocols that allow accurate analysis of microtubule reorganization during cell division in this model.

LLGL2 Inhibits Ovarian Cancer Metastasis by Regulating Cytoskeleton Remodeling via ACTN1

Epithelial ovarian cancer is the most lethal gynecological malignant tumor. Although debulking surgery, chemotherapy, and PARP inhibitors have greatly improved survival, the prognosis for patients with advanced EOC without HRD is still poor. LLGL2, as a cell polarity factor, is involved in maintaining cell polarity and asymmetric cell division. In the study of zebrafish development, LLGL2 regulated the proliferation and migration of epidermal cells and the formation of cortical F-actin. However, the role of LLGL2 in ovarian cancer has not been described. Our study found, through bioinformatics analysis, that low expression of LLGL2 was significantly associated with a more advanced stage and a higher grade of EOC and a poorer survival of patients. Functional experiments that involved LLGL2 overexpression and knockdown showed that LLGL2 inhibited the migration and invasion abilities of ovarian cancer cells in vitro, without affecting their proliferation. LLGL2-overexpressing mice had fewer metastatic implant foci than the controls in vivo. Mechanistically, immunoprecipitation combined with mass spectrometry analysis suggested that LLGL2 regulated cytoskeletal remodeling by interacting with ACTN1. LLGL2 altered the intracellular localization and function of ACTN1 without changing its protein and mRNA levels. Collectively, we uncovered that LLGL2 impaired actin filament aggregation into bundles by interacting with ACTN1, which led to cytoskeleton remodeling and inhibition of the invasion and metastasis of ovarian cancer cells.

CRB3 navigates Rab11 trafficking vesicles to promote γTuRC assembly during ciliogenesis

The primary cilium plays important roles in regulating cell differentiation, signal transduction, and tissue organization. Dysfunction of the primary cilium can lead to ciliopathies and cancer. The formation and organization of the primary cilium are highly associated with cell polarity proteins, such as the apical polarity protein CRB3. However, the molecular mechanisms by which CRB3 regulates ciliogenesis and the location of CRB3 remain unknown. Here, we show that CRB3, as a navigator, regulates vesicle trafficking in γ-tubulin ring complex (γTuRC) assembly during ciliogenesis and cilium-related Hh and Wnt signaling pathways in tumorigenesis. Crb3 knockout mice display severe defects of the primary cilium in the mammary ductal lumen and renal tubule, while mammary epithelial-specific Crb3 knockout mice exhibit the promotion of ductal epithelial hyperplasia and tumorigenesis. CRB3 is essential for lumen formation and ciliary assembly in the mammary epithelium. We demonstrate that CRB3 localizes to the basal body and that CRB3 trafficking is mediated by Rab11-positive endosomes. Significantly, CRB3 interacts with Rab11 to navigate GCP6/Rab11 trafficking vesicles to CEP290, resulting in intact γTuRC assembly. In addition, CRB3-depleted cells are unresponsive to the activation of the Hh signaling pathway, while CRB3 regulates the Wnt signaling pathway. Therefore, our studies reveal the molecular mechanisms by which CRB3 recognizes Rab11-positive endosomes to facilitate ciliogenesis and regulates cilium-related signaling pathways in tumorigenesis.

Non-Solvatochromic Cell Membrane-Targeted NIR Fluorescent Probe for Visualization of Polarity Abnormality in Drug-Induced Liver Injury Mice

Noninvasive visualization of liver polarity by using fluorescence imaging technology is helpful to better understand drug-induced liver injury (DILI). However, cell membrane-targeted polarity-sensitive near-infrared (NIR) fluorescent probes are still scarce. Herein, we report a non-solvatochromic cell membrane-targeted NIR small molecular probe (N-BPM-C10) for monitoring the polarity changes on cell membranes in living cells and in vivo. N-BPM-C10 exhibits polarity-dependent fluorescence around 655 nm without an obvious solvatochromic effect, which endows it with good capability for the in vivo imaging study. Moreover, it can rapidly and selectively light up the cell membranes as well as distinguish tumor cells from normal cells due to its excellent polarity-sensitive ability. More importantly, N-BPM-C10 has been successfully applied to visualize liver polarity changes in vivo, revealing the reduction of liver polarity in DILI mice. We believe that N-BPM-C10 provides a new way for the diagnosis of DILI.

The third dimension of tumor microenvironment-The importance of tumor stroma in 3D cancer models

Recent advances in the three-dimensional (3D) cancer models give rise to a plethora of new possibilities in the development of anti-cancer drug therapies and bring us closer to personalized medicine. Three-dimensional models are undoubtedly more authentic than traditional two-dimensional (2D) cell cultures. Nowadays, they are becoming preferentially used in most cancer research fields due to their more accurate biomimetic characteristics. On the contrary, they still lack the cellular and matrix complexity of the native tumor microenvironment (TME). This review focuses on the description of existing 3D models, the incorporation of TME and fluidics into these models, and their perspective in the future research. It is clear that such an improvement would need not only biological but also technical progress. Therefore, the modern approach to anti-cancer drug discovery should involve various fields.

Multiple organelle-targeted 1,8-naphthyridine derivatives for detecting the polarity of organelles

Four 1,8-naphthyridine derivatives (1a-1d) with different organelle targeting abilities were obtained using the Knoevenagel condensation reaction of 1,8-naphthyridine with 4-(N,N-diethylamino)benzaldehyde (2a), 4-(N,N-diphenylamino)benzaldehyde (2b), 4-(piperazin-1-yl)benzaldehyde (2c) and 4-(ethyl(4-formylphenyl)amino)-N-(2-((4-methylphenyl)sulfonamido)ethyl)butanamide (2d), respectively. The maximal absorption bands of dyes 1a-1d were observed at 375-447 nm, while their maximum emission peaks were situated at 495-605 nm. The optical properties showed that the fluorescence emission of dyes 1a-1d is shifted toward greater wavelengths as the system polarity (Δf) increased. Meanwhile, with increasing polarity of the mixed 1,4-dioxane/H₂O system, the fluorescence intensity of dyes 1a-1d gradually decreased. Furthermore, the fluorescence intensity of 1a-1d enhanced by 12-239 fold as the polarity of 1,4-dioxane/H₂O mixtures declined. 1a-1d had a large Stokes shift (up to 229 nm) in polar solvents in comparison to nonpolar solvents. The colocalization imaging experiments demonstrated that dyes 1a-1d (3-10 μM) were located in mitochondria, lipid droplets, lysosomes and the endoplasmic reticulum in living HeLa cells, respectively; and they could monitor the polarity fluctuation of the corresponding organelles. Consequently, this work proposes a molecular design idea with different organelle targeting capabilities based on the same new fluorophore, and this molecular design idea may provide more alternatives for polarity-sensitive fluorescent probes with organelle targeting.

Selective Visualization of Tumor Cell Membranes and Tumors with a Viscosity-Sensitive Plasma Membrane Probe

Cancer is a worldwide health problem. Revealing the changes in the microenvironment after cell carcinogenesis is helpful to understand cancer and develop sensitive methods for cancer diagnosis. We developed herein a viscosity-responsive plasma membrane probe (TPA-S) that was successfully used to probe the viscosity difference between normal and tumor cell plasma membranes for the first time. The probe shows AIE properties with good water solubility, significant near-infrared (NIR) fluorescence responses to viscosity with high sensitivity, and excellent cell membrane location performance. With these features, our experiments showed that TPA-S could selectively visualize cancer cell plasma membranes, revealing that the plasma membrane of tumor cells is more viscous than that of normal cells. In addition, TPA-S was successfully applied to specifically light up tumors. Altogether, this work explored the changes of cell membrane viscosity after canceration, provided a new method for selective visualization of tumor cells, and opened up a new approach for cancer diagnosis.

Therapeutic Effectiveness of Anticancer Agents Targeting Different Signaling Molecules Involved in Asymmetric Division of Cancer Stem Cell

Intra-tumoral heterogeneity is maintained by cancer stem cells (CSCs) with dysregulated self-renewal and asymmetric cell division (ACD). According to the cancer stem cell theory, by ACD a CSC can generate two daughter progenies with different fates such as one cancer stem cell and one differentiated cell. Therefore, this type of mitotic division supports vital process of the maintenance of CSC population. But this CSC pool reservation by ACD complicates the treatment of cancer patients, as CSCs give rise to aggressive clones which are prone to metastasis and drug-insensitivity. Hence, identification of therapeutic modalities which can target ACD of cancer stem cell is an intriguing part of cancer research. In this review, other than the discussion about the extrinsic inducers of ACD role of different proteins, miRNAs and lncRNAs in this type of cell division is also mentioned. Other than these, mode of action of the proven and potential drugs targeting ACD of CSC is also discussed here.

Multifunctional Fluorescent Probe for Simultaneous Detection of ONOO-, Viscosity, and Polarity and Its Application in Ferroptosis and Cancer Models

Intracellular peroxynitrite anions (ONOO^-) and microenvironments (such as viscosity and polarity) play an important role in maintaining redox homeostasis, regulating diffusion, transportation, and signal transduction in living cells. The abnormality of these factors is often closely related to various physiological/pathological processes. However, owing to the lack of suitable probes, the simultaneous visualization of ONOO^-, viscosity, and polarity in ferroptosis and cancer models has not been achieved. To meet urgent needs, we presented a multifunctional near-infrared (NIR) fluorescent probe, named MQA-P, for simultaneously detecting ONOO^-, viscosity, and polarity within mitochondria. The probe exhibited a remarkable turn-on response to ONOO^- with the far-red emission of about 645 nm and was highly sensitive to viscosity/polarity in the NIR channel with λ_em > 704 nm. Facilitated by MQA-P, for the first time, we revealed that erastin-induced ferroptosis was accompanied by a significant upregulation of ONOO^- and an increase of viscosity (or decrease of polarity) at the same time. Moreover, the concurrent use of ONOO^-, viscosity, and polarity for the diagnosis of cancer has been successfully achieved not only at cell/tissue levels but also in tumor mice models. Compared with detecting only one factor, this simultaneous detection of multimarkers provides a more sensitive and reliable method/tool for tracking ferroptosis-related pathological processes and cancer diagnosis, holding great potential in preclinical research, medical diagnosis, and imaging-guided surgery.

Physical and biological advances in endothelial cell-based engineered co-culture model systems

Scientific knowledge in the field of cell biology and mechanobiology heavily leans on cell-based in vitro experiments and models that favor the examination and comprehension of certain biological processes and occurrences across a variety of environments. Cell culture assays are an invaluable instrument for a vast spectrum of biomedical and biophysical investigations. The quality of experimental models in terms of simplicity, reproducibility, and combinability with other methods, and in particular the scale at which they depict cell fate in native tissues, is critical to advancing the knowledge of the comprehension of cell-cell and cell-matrix interactions in tissues and organs. Typically, in vitro models are centered on the experimental tinkering of mammalian cells, most often cultured as monolayers on planar, two-dimensional (2D) materials. Notwithstanding the significant advances and numerous findings that have been accomplished with flat biology models, their usefulness for generating further new biological understanding is constrained because the simple 2D setting does not reproduce the physiological response of cells in natural living tissues. In addition, the co-culture systems in a 2D stetting weakly mirror their natural environment of tissues and organs. Significant advances in 3D cell biology and matrix engineering have resulted in the creation and establishment of a new type of cell culture shapes that more accurately represents the in vivo microenvironment and allows cells and their interactions to be analyzed in a biomimetic approach. Contemporary biomedical and biophysical science has novel advances in technology that permit the design of more challenging and resilient in vitro models for tissue engineering, with a particular focus on scaffold- or hydrogel-based formats, organotypic cultures, and organs-on-chips, which cover the purposes of co-cultures. Even these complex systems must be kept as simplified as possible in order to grasp a particular section of physiology too very precisely. In particular, it is highly appreciated that they bridge the space between conventional animal research and human (patho)physiology. In this review, the recent progress in 3D biomimetic culturation is presented with a special focus on co-cultures, with an emphasis on the technological building blocks and endothelium-based co-culture models in cancer research that are available for the development of more physiologically relevant in vitro models of human tissues under normal and diseased conditions. Through applications and samples of various physiological and disease models, it is possible to identify the frontiers and future engagement issues that will have to be tackled to integrate synthetic biomimetic culture systems far more successfully into biomedical and biophysical investigations.

Cyclin E overexpression in the Drosophila accessory gland induces tissue dysplasia

The regulation of the cell division cycle is governed by a complex network of factors that together ensure that growing or proliferating cells maintain a stable genome. Defects in this system can lead to genomic instability that can affect tissue homeostasis and thus compromise human health. Variations in ploidy and cell heterogeneity are observed frequently in human cancers. Here, we examine the consequences of upregulating the cell cycle regulator Cyclin E in the Drosophila melanogaster male accessory gland. The accessory gland is the functional analog of the human prostate. This organ is composed of a postmitotic epithelium that is emerging as a powerful in vivo system for modelling different aspects of tumor initiation and progression. We show that Cyclin E upregulation in this model is sufficient to drive tissue dysplasia. Cyclin E overexpression drives endoreplication and affects DNA integrity, which results in heterogeneous nuclear and cellular composition and variable degrees of DNA damage. We present evidence showing that, despite the presence of genotoxic stress, those cells are resistant to apoptosis and thus defective cells are not eliminated from the tissue. We also show that Cyclin E-expressing cells in the accessory gland display mitochondrial DNA aggregates that colocalize with Cyclin E protein. Together, the findings presented here show that Cyclin E upregulation in postmitotic cells of the accessory gland organ causes cellular defects such as genomic instability and mitochondrial defects, eventually leading to tissue dysplasia. This study highlights novel mechanisms by which Cyclin E might contribute to disease initiation and progression.

Histology of metastatic colorectal cancer in a lymph node

BACKGROUND

A primary colorectal cancer (CRC) tumor can contain heterogeneous cancer cells. As clones of cells with different properties metastasize to lymph nodes (LNs), they could show different morphologies. Cancer histologies in LNs of CRC remains to be described.

METHODS

Our study enrolled 318 consecutive patients with CRC who underwent primary tumor resection with lymph node dissection between January 2011 and June 2016. 119 (37.4%) patients who had metastatic LNs (mLNs) were finally included in this study. Cancer histologies in LNs were classified and compared with pathologically diagnosed differentiation in the primary lesion. The association between histologies in lymph node metastasis (LNM) and prognosis in patients with CRC was investigated.

RESULTS

The histologies of the cancer cells in the mLNs were classified into four types: tubular, cribriform, poorly differentiated, and mucinous. Same degree of pathologically diagnosed differentiation in the primary tumor produced various histological types in LNM. In Kaplan-Meier analysis, prognosis was worse in CRC patients with moderately differentiated adenocarcinoma who had at least some mLN also showing cribriform carcinoma than for those whose mLNs all showed tubular carcinoma.

CONCLUSIONS

Histology in LNM from CRC might indicate the heterogeneity and malignant phenotype of the disease.

Cell polarity and extrusion: How to polarize extrusion and extrude misspolarized cells?

The barrier function of epithelia is one of the cornerstones of the body plan organization of metazoans. It relies on the polarity of epithelial cells which organizes along the apico-basal axis the mechanical properties, signaling as well as transport. This barrier function is however constantly challenged by the fast turnover of epithelia occurring during morphogenesis or adult tissue homeostasis. Yet, the sealing property of the tissue can be maintained thanks to cell extrusion: a series of remodeling steps involving the dying cell and its neighbors leading to seamless cell expulsion. Alternatively, the tissue architecture can also be challenged by local damages or the emergence of mutant cells that may alter its organization. This includes mutants of the polarity complexes which can generate neoplastic overgrowths or be eliminated by cell competition when surrounded by wild type cells. In this review, we will provide an overview of the regulation of cell extrusion in various tissues focusing on the relationship between cell polarity, cell organization and the direction of cell expulsion. We will then describe how local perturbations of polarity can also trigger cell elimination either by apoptosis or by cell exclusion, focusing specifically on how polarity defects can be directly causal to cell elimination. Overall, we propose a general framework connecting the influence of polarity on cell extrusion and its contribution to aberrant cell elimination.

Xanthone-based solvatochromic fluorophores for quantifying micropolarity of protein aggregates

Proper three-dimensional structures are essential for maintaining the functionality of proteins and for avoiding pathological consequences of improper folding. Misfolding and aggregation of proteins have been both associated with neurodegenerative disease. Therefore, a variety of fluorogenic tools that respond to both polarity and viscosity have been developed to detect protein aggregation. However, the rational design of highly sensitive fluorophores that respond solely to polarity has remained elusive. In this work, we demonstrate that electron-withdrawing heteroatoms with (d-p)-π* conjugation can stabilize lowest unoccupied molecular orbital (LUMO) energy levels and promote bathochromic shifts. Guided by computational analyses, we have devised a novel series of xanthone-based solvatochromic fluorophores that have rarely been systematically studied. The resulting probes exhibit superior sensitivity to polarity but are insensitive to viscosity. As proof of concept, we have synthesized protein targeting probes for live-cell confocal imaging intended to quantify the polarity of misfolded and aggregated proteins. Interestingly, our results reveal several layers of protein aggregates in a way that we had not anticipated. First, microenvironments with reduced polarity were validated in the misfolding and aggregation of folded globular proteins. Second, granular aggregates of AgHalo displayed a less polar environment than aggregates formed by folded globular protein represented by Htt-polyQ. Third, our studies reveal that granular protein aggregates formed in response to different types of stressors exhibit significant polarity differences. These results show that the solvatochromic fluorophores solely responsive to polarity represent a new class of indicators that can be widely used for detecting protein aggregation in live cells, thus paving the way for elucidating cellular mechanisms of protein aggregation as well as therapeutic approaches to managing intracellular aggregates.

Visualization of a novel human monoclonal antibody against Claudin-3 for targeting ovarian cancer

INTRODUCTION

Claudin-3 (CLDN3), a tight junction protein, regulates cell-to-cell interactions in epithelial or endothelial cell sheets. During tumorigenesis, epithelial cells are transformed, and tumor cells proliferate through out-of-plane division, resulting in external exposure of CLDN3. Since alterations of CLDN3 expression are associated with cancer progression and higher CLDN3 expression is observed in most ovarian cancers, we tested the feasibility of using a CLDN3-specific antibody as a novel imaging tracer.

MATERIALS AND METHODS

After reducing the CLDN3-specific antibodies to expose the -SH groups, click chemistry was used to conjugate the radioactive isotope ¹¹¹In or the fluorescent protein FNR648. Human ovarian cancer OVCAR-3 and glioblastoma U87MG cells were used as CLDN3-positive and -negative cells. Flow cytometry was used to determine the CLDN3 IgG1 monoclonal antibody binding to both cell lines. OVCAR-3 cells were injected subcutaneously into mice to establish a xenograft model. ¹¹¹In-labeled CLDN3 antibodies (370 kBq/50 μL) were administered intravenously into mice. After 24 h, organs, including tumors, were excised and measured with a γ-counter. Images were acquired with the IVIS optical imaging system and SPECT/CT.

RESULTS

The labeling efficiency of NOTA-¹¹¹In and antibody-NOTA-¹¹¹In was 98.52% and 100%, respectively. FNR648-labeled CLDN3 antibody bound to the cell surface of OVCAR-3 and U87MG with 83.4% and 5.7% specificity, respectively. In OVCAR-3 tumor xenografted mice, CLDN3 IgG1 antibody showed a 2.5-fold higher tumor uptake (20.4 ± 7.4% ID/g) than human IgG1 (8.8 ± 2.6% ID/g) at 24 h post injection. The CLDN3 antibody fluorescence signal in the tumor peaked at 24 h post injection.

CONCLUSION

We have successfully conjugated a radioisotope and a fluorescent protein with CLDN3-specific antibodies and verified the specific binding of labeled antibodies to OVCAR-3 tumors in a mouse model. Our data suggested that CLDN3-specific human monoclonal antibodies could be used as a useful theranostic tracer.

A novel coumarin-TPA based fluorescent probe for turn-on hypochlorite detection and lipid-droplet-polarity bioimaging in cancer cells

A novel fluorescent compound, named C-TPA, based on coumarin (acceptor) and triphenylamine (donor) was facilely designed and fabricated through a one-step Suzuki coupling reaction. As a donor group, triphenylamine can efficiently enhance the fluorescence intensity and photostability of coumarin, and thus improve the detection efficiency. C-TPA-S was obtained from C-TPA treated with Lawesson's reagent and C-TPA-S can be used for the turn-on detection of hypochlorite through oxidative desulfurization with a low detection limit of 0.12 μM. Moreover, the intramolecular charge transfer process between the donor and acceptor group endows C-TPA with solvatochromism property and makes C-TPA a good candidate for polarity detection. The C-TPA with bright green fluorescence was highly efficient for imaging the microenvironment of polarity both in living cells and tissues with high selectivity and photostability, which can be applied in the diagnosis for the cancer cells.

Brain metastases: It takes two factors for a primary cancer to metastasize to brain

Brain metastasis of a cancer is a malignant disease with high mortality, but the cause and the molecular mechanism remain largely unknown. Using the samples of primary tumors of 22 cancer types in the TCGA database, we have performed a computational study of their transcriptomic data to investigate the drivers of brain metastases at the basic physics and chemistry level. Our main discoveries are: (i) the physical characteristics, namely electric charge, molecular weight, and the hydrophobicity of the extracellular structures of the expressed transmembrane proteins largely affect a primary cancer cell’s ability to cross the blood-brain barrier; and (ii) brain metastasis may require specific functions provided by the activated enzymes in the metastasizing primary cancer cells for survival in the brain micro-environment. Both predictions are supported by published experimental studies. Based on these findings, we have built a classifier to predict if a given primary cancer may have brain metastasis, achieving the accuracy level at AUC = 0.92 on large test sets.

Rational Design of a Near-Infrared Ratiometric Probe with a Large Stokes Shift: Visualization of Polarity Abnormalities in Non-Alcoholic Fatty Liver Model Mice

Tracking liver polarity with noninvasive and dynamic imaging techniques is helpful to better understand the non-alcoholic fatty liver (NAFL). Herein, a novel near-infrared (NIR) fluorescent probe Cy-Mp is constructed using a "symmetry collapse" strategy. The structure modification leads to the conversion of locally excited state fluorescence to charge transfer state fluorescence. Cy-Mp emits at near-infrared (NIR) wavelengths with high photostability as well as a large Stokes shift. Cy-Mp exhibits a ratiometric response to polarity, providing more accurate analysis of intracellular polarity via the built-in internal reference correction. Most importantly, the in vivo studies indicate that Cy-Mp can accumulate in the liver and the decreased polarity in the liver of mice with NAFL is verified by the ratiometric imaging, implying the great potential of Cy-Mp in the diagnosis of NAFL.

Lack of extracellular matrix switches TGF-β induced apoptosis of endometrial cells to epithelial to mesenchymal transition

The extracellular matrix and the correct establishment of epithelial cell polarity plays a critical role in epithelial cell homeostasis and cell polarity. In addition, loss of tissue structure is a hallmark of carcinogenesis. In this study, we have addressed the role of extracellular matrix in the cellular responses to TGF-β. It is well known that TGF-β is a double-edged sword: it acts as a tumor suppressor in normal epithelial cells, but conversely has tumor-promoting effects in tumoral cells. However, the factors that determine cellular outcome in response to TGF-β remain controversial. Here, we have demonstrated that the lack of extracellular matrix and consequent loss of cell polarity inhibits TGF-β-induced apoptosis, observed when endometrial epithelial cells are polarized in presence of extracellular matrix. Rather, in absence of extracellular matrix, TGF-β-treated endometrial epithelial cells display features of epithelial-to-mesenchymal transition. We have also investigated the molecular mechanism of such a switch in cellular response. On the one hand, we found that the lack of Matrigel results in increased AKT signaling which is sufficient to inhibit TGF-β-induced apoptosis. On the other hand, we demonstrate that TGF-β-induced epithelial-to-mesenchymal transition requires ERK and SMAD2/3 activation. In summary, we demonstrate that loss of cell polarity changes the pro-apoptotic function of TGF-β to tumor-associated phenotype such as epithelial-to-mesenchymal transition. These results may be important for understanding the dual role of TGF-β in normal versus tumoral cells.

Contribution of the Testosterone Androgen Receptor–PARD3B Signaling Axis to Tumorigenesis and Malignance of Glioblastoma Multiforme through Stimulating Cell Proliferation and Colony Formation

Background: Glioblastoma multiforme (GBM) is the most common and malignant brain tumor with very poor prognoses. After surgical resection of the primary tumor, rapid proliferation of residual glioblastoma cells is a critical cause explaining tumor malignance and recurrence. In this study, we evaluated de novo roles of the testosterone androgen receptor (AR)–PARD3B signaling axis in the tumorigenesis and malignance of human GBM and the possible related mechanisms. Methods: AR and PARD3B gene expressions and their correlations were mined from The Cancer Genome Atlas (TCGA) database and analyzed using the UALCAN system. Analyses using a real-time PCR, cell proliferation, and colony formation and a loss-of-function strategy by suppressing AR activity with its specific inhibitor, enzalutamide, were then carried out to determine roles of the testosterone AR–PARD3B signaling axis in tumor malignance. Results: Expressions of AR, PARD3B mRNA, and proteins in human GBM tissues were upregulated compared to normal human brain tissues. In contrast, levels of AR and PARD3B mRNA in most TCGA pan-cancer types were downregulated compared to their respective normal tissues. Interestingly, a highly positive correlation between AR and PARD3B gene expressions in human GBM was identified. The results of a bioinformatics search further showed that there were five AR-specific DNA-binding elements predicted in the 5′ promoter of the PARD3B gene. Regarding the mechanisms, exposure of human glioblastoma cells to testosterone induced AR and PARD3B gene expressions and successively stimulated cell proliferation and colony formation. Suppressing AR activity concurrently resulted in significant attenuations of testosterone-induced PARD3B gene expression, cell proliferation, and colony formation in human glioblastoma cells. Conclusions: This study showed the contribution of the testosterone AR–PARD3B signaling axis to the tumorigenesis and malignance of human GBM through stimulating cell proliferation and colony formation. Therefore, the AR-PARD3B signaling axis could be targeted for potential therapy for human GBM.

Statistical parametrization of cell cytoskeleton reveals lung cancer cytoskeletal phenotype with partial EMT signature

Epithelial–mesenchymal Transition (EMT) is a multi-step process that involves cytoskeletal rearrangement. Here, developing and using an image quantification tool, Statistical Parametrization of Cell Cytoskeleton (SPOCC), we have identified an intermediate EMT state with a specific cytoskeletal signature. We have been able to partition EMT into two steps: (1) initial formation of transverse arcs and dorsal stress fibers and (2) their subsequent conversion to ventral stress fibers with a concurrent alignment of fibers. Using the Orientational Order Parameter (OOP) as a figure of merit, we have been able to track EMT progression in live cells as well as characterize and quantify their cytoskeletal response to drugs. SPOCC has improved throughput and is non-destructive, making it a viable candidate for studying a broad range of biological processes. Further, owing to the increased stiffness (and by inference invasiveness) of the intermediate EMT phenotype compared to mesenchymal cells, our work can be instrumental in aiding the search for future treatment strategies that combat metastasis by specifically targeting the fiber alignment process.

A computational method for automated quantification of actin stress fiber alignment in fluorescence images of cultured cells is presented, used to detect changes in stress fiber organization during EMT, with pathways regulating actin dynamics manipulated leading to the discovery of a cytoskeletal phenotype.

A 3D-printed scaffold-based osteosarcoma model allows to investigate tumor phenotypes and pathogenesis in an in vitro bone-mimicking niche

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Similar mechanical and structural properties as cortical bones.

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Recapitulating osteosarcoma phenotypes in morphology, proliferation, cytoskeleton re-organization and energy expenditure.

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A remarkable potential of ECM remodeling.

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The transcriptomic analysis to uncover distinct signaling pathways and molecules.

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Similar expression patterns of biomarkers as clinical trials.

DGKZ promotes TGFβ signaling pathway and metastasis in triple-negative breast cancer by suppressing lipid raft-dependent endocytosis of TGFβR2

Diacylglycerol kinase ζ (DGKZ) is a diacylglycerol kinase that metabolizes diacylglycerol to yield phosphatidic acid, and its function in breast cancer progression remains unclear. In this study, via screening of a CRISPR-Cas9 knockout library containing lipid metabolic genes, DGKZ was identified as a potential prometastatic gene. We first confirmed that high DGKZ expression correlated with tumor progression and poor prognosis in patients. Next, knockout of DGKZ in triple-negative breast cancer cell lines were found to significantly inhibit metastatic behaviors in vitro and in vivo, whereas its overexpression increased the metastatic potential of cell lines. Mechanistic studies based on RNA sequencing and bioinformatic analysis indicated that DGKZ might regulate cell metastasis by promoting epithelial–mesenchymal transition via the transforming growth factor β (TGFβ) signaling pathway. Furthermore, we found that overexpression of DGKZ activated the TGFβ/TGFβR2/Smad3 signaling pathway by inhibiting the degradation of TGFβR2 through suppression of caveolin/lipid raft-dependent endocytosis. Moreover, the caveolin/lipid raft-dependent endocytosis of TGFβR2 was regulated by the metabolite phosphatidic acid, which might alter TGFβR2 partitioning in lipid rafts and nonlipid rafts by affecting the fluidity of the plasma membrane. These findings suggested that DGKZ is a novel promoter of metastasis and that it could be a potential prognostic indicator in patients with triple-negative breast cancer.

Biomarkers to Detect Early-Stage Colorectal Cancer

Colorectal cancer is a leading cause of mortality worldwide. The high incidence and the acceleration of incidence in younger people reinforces the need for better techniques of early detection. The use of noninvasive biomarkers has potential to more accurately inform how patients are prioritised for clinical investigation, which, in turn, may ultimately translate into improved survival for those subsequently found to have curable-stage CRC. This review surveys a wide range of CRC biomarkers that may (alone or in combination) identify symptomatic patients presenting in primary care who should be progressed for clinical investigation.

AVL9 promotes colorectal carcinoma cell migration via regulating EGFR expression

Background

Despite advanced treatments could inhibit progression of colorectal carcinoma (CRC), the recurrence and metastasis remain challenging issues. Accumulating evidences implicated that AVL9 played a vital role in human cancers, but it’s biological function and mechanism in CRC remain unclear.

Aim

To investigate the biological role and mechanism of AVL9 in colorectal carcinoma.

Results

AVL9 expression was significantly upregulated in tumor tissues than that in matched normal tissues both at mRNA and protein levels. High expression of AVL9 was closely correlated with M status, stages and poor prognosis of colorectal carcinoma (CRC) patients. Functionally, AVL9 overexpression promoted cell migration rather than cell proliferation in vitro, whereas AVL9 knockdown exhibited the contrary results. Mechanistically, AVL9 regulated EGFR expression, and knockdown of EGFR restrained AVL9-induced cell migration.

Conclusion

These findings demonstrated that AVL9 contributed to CRC cell migration by regulating EGFR expression, suggesting a potential biomarker and treatment target for CRC.

Near-infrared (NIR) fluorescence-emitting small organic molecules for cancer imaging and therapy

We discuss recent advances made in the development of NIR fluorescence-emitting small organic molecules for tumor imaging and therapy.

Identification of Pan-Cancer Biomarkers Based on the Gene Expression Profiles of Cancer Cell Lines

There are many types of cancers. Although they share some hallmarks, such as proliferation and metastasis, they are still very different from many perspectives. They grow on different organ or tissues. Does each cancer have a unique gene expression pattern that makes it different from other cancer types? After the Cancer Genome Atlas (TCGA) project, there are more and more pan-cancer studies. Researchers want to get robust gene expression signature from pan-cancer patients. But there is large variance in cancer patients due to heterogeneity. To get robust results, the sample size will be too large to recruit. In this study, we tried another approach to get robust pan-cancer biomarkers by using the cell line data to reduce the variance. We applied several advanced computational methods to analyze the Cancer Cell Line Encyclopedia (CCLE) gene expression profiles which included 988 cell lines from 20 cancer types. Two feature selection methods, including Boruta, and max-relevance and min-redundancy methods, were applied to the cell line gene expression data one by one, generating a feature list. Such list was fed into incremental feature selection method, incorporating one classification algorithm, to extract biomarkers, construct optimal classifiers and decision rules. The optimal classifiers provided good performance, which can be useful tools to identify cell lines from different cancer types, whereas the biomarkers (e.g. NCKAP1, TNFRSF12A, LAMB2, FKBP9, PFN2, TOM1L1) and rules identified in this work may provide a meaningful and precise reference for differentiating multiple types of cancer and contribute to the personalized treatment of tumors.

Transcriptional Control of Apical-Basal Polarity Regulators

Cell polarity is essential for many functions of cells and tissues including the initial establishment and subsequent maintenance of epithelial tissues, asymmetric cell division, and morphogenetic movements. Cell polarity along the apical-basal axis is controlled by three protein complexes that interact with and co-regulate each other: The Par-, Crumbs-, and Scrib-complexes. The localization and activity of the components of these complexes is predominantly controlled by protein-protein interactions and protein phosphorylation status. Increasing evidence accumulates that, besides the regulation at the protein level, the precise expression control of polarity determinants contributes substantially to cell polarity regulation. Here we review how gene expression regulation influences processes that depend on the induction, maintenance, or abolishment of cell polarity with a special focus on epithelial to mesenchymal transition and asymmetric stem cell division. We conclude that gene expression control is an important and often neglected mechanism in the control of cell polarity.

Drosophila ßHeavy-Spectrin is required in polarized ensheathing glia that form a diffusion-barrier around the neuropil

In the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the Drosophila CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments, contribute to the formation of an internal diffusion barrier. We find that ensheathing glia are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP₃) and the Na⁺/K⁺-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP₂) that is supported by a sub-membranous ß_Heavy-Spectrin cytoskeleton. ß_Heavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP₂ and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function.

Chronic arsenic increases cell migration in BEAS-2B cells by increasing cell speed, cell persistence, and cell protrusion length

There is a strong association between arsenic exposure and lung cancer development, however, the mechanism by which arsenic exposure leads to carcinogenesis is not clear. In our previous study, we observed that when BEAS-2B cells are chronically exposed to arsenic, there is an increase in secreted TGFα, as well as an increase in EGFR expression and activity. Further, these changes were broadly accompanied with an increase in cell migration. The overarching goal of this study was to acquire finer resolution of the arsenic-dependent changes in cell migration, as well as to understand the role of increased EGFR expression and activity levels in the underlying mechanisms of cell migration. To do this, we used a combination of biochemical and single cell assays, and observed chronic arsenic treatment enhancing cell migration by increasing cell speed, cell persistence and cell protrusion length. All three parameters were further increased by the addition of TGFα, indicating EGFR activity is sufficient to enhance those aspects of cell migration. In contrast, EGFR activity was necessary for the increase in cell speed, as it was reversed with an EGFR inhibitor, AG1478, but was not necessary to enhance persistence and protrusion length. From these data, we were able to isolate both EGFR-dependent and -independent features of cell migration that were enhanced by chronic arsenic exposure.

Screening of dicyanoisophorone-based probes for highly sensitive detection of viscosity changes in living cells and zebrafish

Herein, seven viscosity-sensitive probes were developed via simple structural modification of dicyanoisophorone (DCO)-derived dyes. Among them, DCO-5 significantly enhances (180-fold) the response signal in highly viscous aqueous media while showing insensitivity to polarity changes or pH variations, and enables the successful detection of viscosity changes in nystatin-treated HepG2 cells, PC 12 cells and zebrafish.

Phase Separation in Cell Polarity

Cells are biochemically and morphologically polarized, which allows them to produce different cell shapes for various functions. Remarkably, some polarity protein complexes are asymmetrically recruited and concentrated on limited membrane regions, which is essential for the establishment and maintenance of diverse cell polarity. Though the components and mutual interactions within these protein complexes have been extensively investigated, how these proteins autonomously concentrate at local membranes and whether they have the same organization mechanism in the condensed assembly as that in aqueous solution remain elusive. A number of recent studies suggest that these highly concentrated polarity protein assemblies are membraneless biomolecular condensates which form through liquid-liquid phase separation (LLPS) of specific proteins. In this perspective, we summarize the LLPS-driven condensed protein assemblies found in asymmetric cell division, epithelial cell polarity, and neuronal synapse formation and function. These findings suggest that LLPS may be a general strategy for cells to achieve local condensation of specific proteins, thus establishing cell polarity.

Real-Time Visualization and Monitoring of Physiological Dynamics by Aggregation-Induced Emission Luminogens (AIEgens)

Physiological dynamics in living cells and tissues are crucial for maintenance and regulation of their normal activities and functionalities. Tiny fluctuations in physiological microenvironments can leverage significant influences on cell growth, metabolism, differentiation, and apoptosis as well as disease evolution. Fluorescence imaging based on aggregation-induced emission luminogens (AIEgens) exhibits superior advantages in real-time sensing and monitoring of the physiological dynamics in living systems, including its unique properties such as high sensitivity and rapid response, flexible molecular design, and versatile nano- to mesostructural fabrication. The introduction of canonic AIEgens with long-wavelength, near-infrared, or microwave emission, persistent luminescence, and diversified excitation source (e.g., chemo- or bioluminescence) offers researchers a tool to evaluate the resulting molecules with excellent performance in response to subtle fluctuations in bioactivities with broader dimensionalities and deeper hierarchies.

EpCAM-claudin-tetraspanin-modulated ovarian cancer progression and drug resistance

Alterations of cell adhesion are involved in cancer progression, but the mechanisms underlying the progression and cell adhesion have remained poorly understood. Focusing on the complex between EpCAM, claudins and tetraspanins, we described a sequence of events by which of the molecules associate each other in ovarian cancer. The interactions between molecules were evaluated by immunoprecipitations and then immunoblotting. To identify the effects of complex formation on the ovarian cancer progression, the different types of ovarian cancer cell lines were compared. In this study, we report the identification of the EpCAM-claudin-4 or -7-CD82 complex in the ovarian cancer progression and metastasis in vitro. Additionally, we demonstrated palmitoylation and intra- or extra-cellular regions are critically required for the complex formation. These results represent the first direct evidence for the link between the dynamism of cell adhesion molecules and ovarian cancer progression.

Wallenda-Nmo Axis Regulates Growth via Hippo Signaling

Both Hippo signaling pathways and cell polarity regulation are critical for cell proliferation and the maintenance of tissue homeostasis, despite the well-established connections between cell polarity disruption and Hippo inactivation, the molecular mechanism by which aberrant cell polarity induces Hippo-mediated overgrowth remains underexplored. Here we use Drosophila wing discs as a model and identify the Wnd-Nmo axis as an important molecular link that bridges loss-of-cell polarity-triggered Hippo inactivation and overgrowth. We show that Wallenda (Wnd), a MAPKKK (mitogen-activated protein kinase kinase kinase) family member, is a novel regulator of Hippo pathways in Drosophila and that overexpression of Wnd promotes growth via Nemo (Nmo)- mediated Hippo pathway inactivation. We further demonstrate that both Wnd and Nmo are required for loss-of-cell polarity-induced overgrowth and Hippo inactivation. In summary, our findings provide a novel insight on how cell polarity loss contributes to overgrowth and uncover the Wnd-Nmo axis as an essential additional branch that regulates Hippo pathways in Drosophila.

Dual β-Catenin and γ-Catenin Loss in Hepatocytes Impacts Their Polarity through Altered Transforming Growth Factor-β and Hepatocyte Nuclear Factor 4α Signaling

Hepatocytes are highly polarized epithelia. Loss of hepatocyte polarity is associated with various liver diseases, including cholestasis. However, the molecular underpinnings of hepatocyte polarization remain poorly understood. Loss of β-catenin at adherens junctions is compensated by γ-catenin and dual loss of both catenins in double knockouts (DKOs) in mice liver leads to progressive intrahepatic cholestasis. However, the clinical relevance of this observation, and further phenotypic characterization of the phenotype, is important. Herein, simultaneous loss of β-catenin and γ-catenin was identified in a subset of liver samples from patients of progressive familial intrahepatic cholestasis and primary sclerosing cholangitis. Hepatocytes in DKO mice exhibited defects in apical-basolateral localization of polarity proteins, impaired bile canaliculi formation, and loss of microvilli. Loss of polarity in DKO livers manifested as epithelial-mesenchymal transition, increased hepatocyte proliferation, and suppression of hepatocyte differentiation, which was associated with up-regulation of transforming growth factor-β signaling and repression of hepatocyte nuclear factor 4α expression and activity. In conclusion, concomitant loss of the two catenins in the liver may play a pathogenic role in subsets of cholangiopathies. The findings also support a previously unknown role of β-catenin and γ-catenin in the maintenance of hepatocyte polarity. Improved understanding of the regulation of hepatocyte polarization processes by β-catenin and γ-catenin may potentially benefit development of new therapies for cholestasis.