Single cell polarity in liquid phase facilitates tumour metastasis

Fluorescence and Lifetime Imaging of Endoplasmic Reticulum Polarity Change During Ferroptosis

As a new form of regulated cell death, ferroptosis is closely related to various diseases. Tracing ferroptosis related biological behavior is helpful to better understand this process and its related biology. Considering that ferroptosis is featured with remarkable lipid peroxidation which can easily change the membranes' compositions and structures, it is potential to detect intracellular environmental changes for direct assessment of ferroptosis. In view of the close relationship between endoplasmic reticulum (ER) and ferroptosis, we designed an ER-targeted and polarity-sensitive fluorescent probe SBD-CH, which has superior photostability and can respond to polarity with high selectivity without the affection of viscosity. SBD-CH can monitor the trend of ER polarity during ferroptosis by confocal laser scanning microscopy (CLSM), and analyze the distribution of polarity in ferroptosis by fluorescence lifetime imaging microscopy (FLIM). During Erastin induced ferroptosis, the polarity of ER in HT-1080 cells increased and the polarity distribution in ER was more dispersed. Our work provides an effective strategy for evaluating the process of ferroptosis by monitoring the changes of ER polarity.

Tumor-treating fields in cancer therapy: advances of cellular and molecular mechanisms

Tumor-Treating Fields (TTFields) use intermediate-frequency and low-intensity electric fields to inhibit tumor cells. However, their mechanisms are still not well understood. This article reviews their key antitumor mechanisms at the cellular and molecular levels, including inhibition of proliferation, induction of death, disturbance of migration, and activation of the immune system. The multifaceted biological effects in combination with other cancer treatments are also summarized. The deep insight into their mechanism will help develop more potential antitumor treatments.

The intricate dance of tumor evolution: Exploring immune escape, tumor migration, drug resistance, and treatment strategies

Recent research has unveiled fascinating insights into the intricate mechanisms governing tumor evolution. These studies have illuminated how tumors adapt and proliferate by exploiting various factors, including immune evasion, resistance to therapeutic drugs, genetic mutations, and their ability to adapt to different environments. Furthermore, investigations into tumor heterogeneity and chromosomal aberrations have revealed the profound complexity that underlies the evolution of cancer. Emerging findings have also underscored the role of viral influences in the development and progression of cancer, introducing an additional layer of complexity to the field of oncology. Tumor evolution is a dynamic and complex process influenced by various factors, including immune evasion, drug resistance, tumor heterogeneity, and viral influences. Understanding these elements is indispensable for developing more effective treatments and advancing cancer therapies. A holistic approach to studying and addressing tumor evolution is crucial in the ongoing battle against cancer. The main goal of this comprehensive review is to explore the intricate relationship between tumor evolution and critical aspects of cancer biology. By delving into this complex interplay, we aim to provide a profound understanding of how tumors evolve, adapt, and respond to treatment strategies. This review underscores the pivotal importance of comprehending tumor evolution in shaping effective approaches to cancer treatment.

Cooperative polarization of MCAM/CD146 and ERM family proteins in melanoma

The WRAMP structure is a protein network associated with tail-end actomyosin contractility, membrane retraction, and directional persistence during cell migration. A marker of WRAMP structures is melanoma cell adhesion molecule (MCAM) which dynamically polarizes to the cell rear. However, factors that mediate MCAM polarization are still unknown. In this study, BioID using MCAM as bait identifies the ERM family proteins, moesin, ezrin, and radixin, as WRAMP structure components. We also present a novel image analysis pipeline, Protein Polarity by Percentile ("3P"), which classifies protein polarization using machine learning and facilitates quantitative analysis. Using 3P, we find that depletion of moesin, and to a lesser extent ezrin, decreases the proportion of cells with polarized MCAM. Furthermore, although copolarized MCAM and ERM proteins show high spatial overlap, 3P identifies subpopulations with ERM proteins closer to the cell periphery. Live-cell imaging confirms that MCAM and ERM protein polarization is tightly coordinated, but ERM proteins enrich at the cell edge first. Finally, deletion of a juxtamembrane segment in MCAM previously shown to promote ERM protein interactions impedes MCAM polarization. Our findings highlight the requirement for ERM proteins in recruitment of MCAM to WRAMP structures and an advanced computational tool to characterize protein polarization.

Cell polarity changes in cancer initiation and progression

Cell polarity, which consists of the morphological, structural, and functional organization of cells along a defined axis, is a feature of healthy cells and tissues. In contrast, abnormal polarity is a hallmark of cancer cells. At the molecular level, key evolutionarily conserved proteins that control polarity establishment and maintenance in various contexts are frequently altered in cancer, but the relevance of these molecular alterations in the oncogenic processes is not always clear. Here, we summarize the recent findings, shedding new light on the involvement of polarity players in cancer development, and discuss the possibility of harnessing cell polarity changes to better predict, diagnose, and cure cancers.

Analysis of cortical cell polarity by imaging flow cytometry

Metastasis is the main cause of cancer-related death and therapies specifically targeting metastasis are highly needed. Cortical cell polarity (CCP) is a prometastatic property of circulating tumor cells affecting their ability to exit blood vessels and form new metastases that constitute a promising point of attack to prevent metastasis. However, conventional fluorescence microscopy on single cells and manual quantification of CCP are time-consuming and unsuitable for screening regulators. In this study, we developed an imaging flow cytometry-based method for high-throughput screening of factors affecting CCP in melanoma cells. The artificial intelligence-supported analysis method we developed is highly reproducible, accurate, and orders of magnitude faster than manual quantification. Additionally, this method is flexible and can be adapted to include additional cellular parameters. In a small-scale pilot experiment using polarity-, cytoskeleton-, or membrane-affecting drugs, we demonstrate that our workflow provides a straightforward and efficient approach for screening factors affecting CCP in cells in suspension and provide insights into the specific function of these drugs in this cellular system. The method and workflow presented here will facilitate large-scale studies to reveal novel cell-intrinsic as well as systemic factors controlling CCP during metastasis.

Inhibition of TRPV4 remodels single cell polarity and suppresses the metastasis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumor, frequently causing both intrahepatic and extrahepatic metastases. The overall prognosis of patients with metastatic HCC is poor. Recently, single-cell (sc) polarity is proved to be an innate feature of some tumor cells in liquid phase, and directly involved in the cell adhesion to blood vessel and tumor metastasis. Here, we characterize the maintained sc polarity of HCC cells in a suspension culture, and investigate its roles and regulatory mechanisms during metastasis. We demonstrate that transient receptor potential vanilloid 4 (TRPV4) is a promoting regulator of sc polarity via activating Ca²⁺-dependent AMPK/MLC/ERM pathway. This attenuates the adhesion of metastatic HCC cells to vascular endothelial cells. The reduction of cancer metastases can result from TRPV4 inhibition, which not only impacts the migration and invasion of tumor cells, but also prevents the adhesion to vascular endothelial cells. Additionally, we discover a brand-new TRPV4 inhibitor called GL-V9 that modifies the degree of sc polarization and significantly decreases the metastatic capacity of HCC cells. Taken together, our data shows that TRPV4 and calcium signal are significant sc polarity regulators in metastatic HCC, and that the pharmacological intervention that results in HCC cells becoming depolarized suggests a promising treatment for cancer metastasis.

TRPV4 Promotes Metastasis in Melanoma by Regulating Cell Motility through Cytoskeletal Rearrangement

The abnormal expression of Transient Receptor Potential cation channel subfamily V member 4 (TRPV4) is closely related to the progression of multiple tumors. In addition, TRPV4 is increasingly being considered a potential target for cancer therapy, especially in tumor metastasis prevention. However, the biological correlation between TRPV4 and tumor metastasis, as well as the specific role of TRPV4 in malignant melanoma metastasis, is poorly understood. In this study, we aimed to examine the role of TRPV4 in melanoma metastasis through experiments and clinical data analysis, and the underlying anticancer mechanism of Baicalin, a natural compound, and its inhibitory effect on TRPV4 with in vivo and in vitro experiments. Our findings suggested that TRPV4 promotes metastasis in melanoma by regulating cell motility via rearranging the cytoskeletal, and Baicalin can inhibit cancer metastasis, whose mechanisms reverse the recruitment of activated cofilin to leading-edge protrusion and the increasing phosphorylation level of cortactin, which is provoked by TRPV4 activation.

Cancer metastasis chemoprevention prevents circulating tumour cells from germination

The war against cancer traces back to the signature event half-a-century ago when the US National Cancer Act was signed into law. The cancer crusade costs trillions with disappointing returns, teasing the possibility of a new breakthrough. Cure for cancer post-metastases still seems tantalisingly out of reach. Once metastasized, cancer-related death is extremely difficult, if not impossible, to be reversed. Here we present cancer pre-metastasis chemoprevention strategy that can prevent circulating tumour cells (CTCs) from initiating metastases safely and effectively, and is disparate from the traditional cancer chemotherapy and cancer chemoprevention. Deep learning of the biology of CTCs and their disseminating organotropism, complexity of their adhesion to endothelial niche reveals that if the adhesion of CTCs to their metastasis niche (the first and the most important part in cancer metastatic cascade) can be pharmaceutically interrupted, the lethal metastatic cascade could be prevented from getting initiated. We analyse the key inflammatory and adhesive factors contributing to CTC adhesion/germination, provide pharmacological fundamentals for abortifacients to intervene CTC adhesion to the distant metastasis sites. The adhesion/inhibition ratio (AIR) is defined for selecting the best cancer metastasis chemopreventive candidates. The successful development of such new therapeutic modalities for cancer metastasis chemoprevention has great potential to revolutionise the current ineffective post-metastasis treatments.

Hypoxia and Ezrin Expression in Primary Melanoma Have High Prognostic Relevance

Hypoxia affects tumor aggressiveness and activates pathways associated with epithelial mesenchymal transition (EMT) which are crucial for tumor progress. In this study, the correlation of hypoxia and EMT with sentinel lymph node status and tumor-specific survival was investigated in primary melanomas. CD34 for capillary count and Hypoxia inducible factor-1α (HIF-1α) as hypoxia indicators as well as Ezrin and L1-Cell Adhesion Molecule (L1CAM), both critical proteins contributing to EMT, were analyzed using immunohistochemistry in 49 melanoma patients with long follow-up (F/U, mean 110 months; range 12−263 months). We found a significant correlation between Breslow tumor thickness and Ezrin expression (p = 0.018). L1CAM expression in primary melanoma was significantly associated with HIF-1α expression (p < 0.0001) and sentinel lymph node metastasis (p = 0.011). Furthermore, low capillary count, reflecting hypoxic condition, was significantly associated with Ezrin expression (p = 0.047) and decreased tumor-specific survival (p = 0.035). In addition, patients with high Ezrin expression in their primary melanoma had a dramatic loss of life early in their F/U period (mean survival time 29 months; range 15−44 month). Our results highlight the relevance of Ezrin, L1CAM and HIF-1α as prognostic markers in melanoma patients. Additionally, we demonstrate that hypoxia in primary melanoma affects EMT and is at least partly responsible for early metastatic dissemination.

Apical-basal polarity and the control of epithelial form and function

Epithelial cells are the most common cell type in all animals, forming the sheets and tubes that compose most organs and tissues. Apical-basal polarity is essential for epithelial cell form and function, as it determines the localization of the adhesion molecules that hold the cells together laterally and the occluding junctions that act as barriers to paracellular diffusion. Polarity must also target the secretion of specific cargoes to the apical, lateral or basal membranes and organize the cytoskeleton and internal architecture of the cell. Apical-basal polarity in many cells is established by conserved polarity factors that define the apical (Crumbs, Stardust/PALS1, aPKC, PAR-6 and CDC42), junctional (PAR-3) and lateral (Scribble, DLG, LGL, Yurt and RhoGAP19D) domains, although recent evidence indicates that not all epithelia polarize by the same mechanism. Research has begun to reveal the dynamic interactions between polarity factors and how they contribute to polarity establishment and maintenance. Elucidating these mechanisms is essential to better understand the roles of apical-basal polarity in morphogenesis and how defects in polarity contribute to diseases such as cancer.

Regulation of the COPII secretory machinery via focal adhesions and extracellular matrix signaling

Proteins that enter the secretory pathway are transported from their place of synthesis in the endoplasmic reticulum to the Golgi complex by COPII-coated carriers. The networks of proteins that regulate these components in response to extracellular cues have remained largely elusive. Using high-throughput microscopy, we comprehensively screened 378 cytoskeleton-associated and related proteins for their functional interaction with the coat protein complex II (COPII) components SEC23A and SEC23B. Among these, we identified a group of proteins associated with focal adhesions (FERMT2, MACF1, MAPK8IP2, NGEF, PIK3CA, and ROCK1) that led to the downregulation of SEC23A when depleted by siRNA. Changes in focal adhesions induced by plating cells on ECM also led to the downregulation of SEC23A and decreases in VSVG transport from ER to Golgi. Both the expression of SEC23A and the transport defect could be rescued by treatment with a focal adhesion kinase inhibitor. Altogether, our results identify a network of cytoskeleton-associated proteins connecting focal adhesions and ECM-related signaling with the gene expression of the COPII secretory machinery and trafficking.

Reversing the Epithelial-Mesenchymal Transition in Metastatic Cancer Cells Using CD146-Targeted Black Phosphorus Nanosheets and a Mild Photothermal Treatment

Cancer metastasis leads to most deaths in cancer patients, and the epithelial-mesenchymal transition (EMT) is the key mechanism that endows the cancer cells with strong migratory and invasive abilities. Here, we present a nanomaterial-based approach to reverse the EMT in cancer cells by targeting an EMT inducer, CD146, using engineered black phosphorus nanosheets (BPNSs) and a mild photothermal treatment. We demonstrate this approach can convert highly metastatic, mesenchymal-type breast cancer cells to an epithelial phenotype (i.e., reversing EMT), leading to a complete stoppage of cancer cell migration. By using advanced nanomechanical and super-resolution imaging, complemented by immunoblotting, we validate the phenotypic switch in the cancer cells, as evidenced by the altered actin organization and cell morphology, downregulation of mesenchymal protein markers, and upregulation of epithelial protein markers. We also elucidate the molecular mechanism behind the reversal of EMT. Our results reveal that CD146-targeted BPNSs and a mild photothermal treatment synergistically contribute to EMT reversal by downregulating membrane CD146 and perturbing its downstream EMT-related signaling pathways. Considering CD146 overexpression has been confirmed on the surface of a variety of metastatic, mesenchymal-like cancer cells, this approach could be applicable for treating various cancer metastasis via modulating the phenotype switch in cancer cells.

Circulating Tumor Cells in Breast Cancer Patients: A Balancing Act between Stemness, EMT Features and DNA Damage Responses

Circulating tumor cells (CTCs) traverse vessels to travel from the primary tumor to distant organs where they adhere, transmigrate, and seed metastases. To cope with these challenges, CTCs have reached maximal flexibility to change their differentiation status, morphology, migratory capacity, and their responses to genotoxic stress caused by metabolic changes, hormones, the inflammatory environment, or cytostatic treatment. A significant percentage of breast cancer cells are defective in homologous recombination repair and other mechanisms that protect the integrity of the replication fork. To prevent cell death caused by broken forks, alternative, mutagenic repair, and bypass pathways are engaged but these increase genomic instability. CTCs, arising from such breast tumors, are endowed with an even larger toolbox of escape mechanisms that can be switched on and off at different stages during their journey according to the stress stimulus. Accumulating evidence suggests that DNA damage responses, DNA repair, and replication are integral parts of a regulatory network orchestrating the plasticity of stemness features and transitions between epithelial and mesenchymal states in CTCs. This review summarizes the published information on these regulatory circuits of relevance for the design of biomarkers reflecting CTC functions in real-time to monitor therapeutic responses and detect evolving chemoresistance mechanisms.

Collective dynamics of gastric cancer cells in fluid

Gastric cancer (GC) is the most common digestive system malignant cancer, and gastric cancer cells (GCC) can migrate in normal solid tissue and lymphatic fluid. Previously, much research has focused on the migration process when the cells are in the solid condition, such as migration through tissue, adhesion, and invasion processes, while little is known about the migration process of GCC in lymphatic fluid. In the current study, we investigate the migration of GCC in a fluid condition in an in vitro environment. We find that the cells diffuse mainly because of their cell viability. Therefore, despite the fact that lymph fluid is almost quiescent, GCCs can migrate around easily. The dynamics of cells also demonstrate a collective glassy dynamic similar to ordinary inactive glassy materials. As density of the cells increases, the movement of the cells becomes slower, and the collective dynamic becomes heterogeneous, which is similar to the dynamically heterogeneous behavior in glassy materials. The results will help us gain a better knowledge of the characteristics of GCC dynamics in the liquid phase which is crucial for the understanding of the mechanism for lymphatic metastasis. This can also potentially help early diagnosis of lymph node metastasis in GC and provide new insights for future clinical treatment.

Liquid biopsy in chronic liver disease

Chronic liver diseases account for a considerable toll of incapacities, suffering, deaths, and resources of the nation's health systems. They can be prevented, treated or even cured when the diagnosis is made on time. Traditional liver biopsy remains the gold standard to diagnose liver diseases, but it has several limitations. Liquid biopsy is emerging as a superior alternative to surgical biopsy given that it surpasses the limitations: it is more convenient, readily and repeatedly accessible, safe, cheap, and provides a more detailed molecular and cellular representation of the individual patient's disease. Progress in understanding the molecular and cellular bases of diseased tissues and organs that normally release cells and cellular components into the bloodstream is catapulting liquid biopsy as a source of biomarkers for diagnosis, prognosis, and prediction of therapeutic response, thus supporting the realization of the promises of precision medicine. The review aims to summarize the evidence of the usefulness of liquid biopsy in liver diseases, including the presence of different biomarkers as circulating epithelial cells, cell-free nucleic acids, specific species of DNA and RNA, and the content of extracellular vesicles.

The immunological and metabolic landscape in primary and metastatic liver cancer

The liver is the sixth most common site of primary cancer in humans, and generally arises in a background of cirrhosis and inflammation. Moreover, the liver is frequently colonized by metastases from cancers of other organs (particularly the colon) because of its anatomical location and organization, as well as its unique metabolic and immunosuppressive environment. In this Review, we discuss how the hepatic microenvironment adapts to pathologies characterized by chronic inflammation and metabolic alterations. We illustrate how these immunological or metabolic changes alter immunosurveillance and thus hinder or promote the development of primary liver cancer. In addition, we describe how inflammatory and metabolic niches affect the spreading of cancer metastases into or within the liver. Finally, we review the current therapeutic options in this context and the resulting challenges that must be surmounted.

Mechanical Control of Cell Migration by the Metastasis Suppressor Tetraspanin CD82/KAI1

The plasma membrane is a key actor of cell migration. For instance, its tension controls persistent cell migration and cell surface caveolae integrity. Then, caveolae constituents such as caveolin-1 can initiate a mechanotransduction loop that involves actin- and focal adhesion-dependent control of the mechanosensor YAP to finely tune cell migration. Tetraspanin CD82 (also named KAI-1) is an integral membrane protein and a metastasis suppressor. Its expression is lost in many cancers including breast cancer. It is a strong inhibitor of cell migration by a little-known mechanism. We demonstrated here that CD82 controls persistent 2D migration of EGF-induced single cells, stress fibers and focal adhesion sizes and dynamics. Mechanistically, we found that CD82 regulates membrane tension, cell surface caveolae abundance and YAP nuclear translocation in a caveolin-1-dependent manner. Altogether, our data show that CD82 controls 2D cell migration using membrane-driven mechanics involving caveolin and the YAP pathway.

DCBLD2 Affects the Development of Colorectal Cancer via EMT and Angiogenesis and Modulates 5-FU Drug Resistance

Background: DCBLD2 is highly expressed in various cancers, including colorectal cancer. DCBLD2 overexpression promotes tumor occurrence, development, and metastasis. However, DCBLD2 sensitivity to chemotherapy drugs and its mechanism on tumor development are unknown. Methods: DCBLD2 expression differences in cancer and normal tissues were obtained from GEO and TCGA databases. DCBLD2 influence on prognosis was also compared, and the database analysis results were verified via the analysis of clinical samples. GDSC database was used to analyze the effect of DCBLD2 expression difference on 5-FU drug sensitivity on tumor cells. CCK-8, clone formation, scratch, Transwell invasion and migration assays were used to assess DCBLD2 effects on the proliferation, metastasis, and 5-FU drug sensitivity on HCT116 and Caco-2 colorectal cancer cells. Angiogenesis and Matrigel plug assays were used to study the effect of DCBLD2 on angiogenesis. Q-RCR and Western Blot were used to analyze DCBLD2 impact on the EMT signaling pathway, and TAP-MS assay with Co-IP verification was used to identify the downstream target proteins binding to DCBLD2. Results: Both database and clinical sample validation results showed that the expression of DCBLD2 in colorectal cancer tissues was significantly higher than that in normal tissues, leading to poor prognosis of patients. GDSC database analysis showed that DCBLD2 overexpression caused tumor cell resistance to 5-FU. The results of in vitro and in vivo experiments showed that the inhibition of DCBLD2 reduced the proliferation, migration and invasion of colorectal cancer cells, inhibited the angiogenesis of endothelial cells, and enhanced the drug sensitivity to 5-FU. The results of q-RCR and Western Blot experiments showed that the inhibition of DCBLD2 can suppress the EMT signal. The results of TAP-MS assay showed that the proteins bound to DCBLD2 were enriched to the Focal adhesion pathway. The results of Co-IP assay show that DCBLD2 can combine with ITGB1, the key factor of Focal adhesion pathway. Conclusion: DCBLD2 may affect the development of colorectal cancer by regulating cell proliferation and motility, and modulate 5-FU resistance. Down-regulation of DCBLD2 can inhibit EMT signal and angiogenesis. DCBLD2 can combine with ITGB1, the key signal factor of the Focal adhesion pathway.

A liquid culture cancer spheroid model reveals low PI3K/Akt pathway activity and low adhesiveness to the extracellular matrix

Three-dimensional (3D) cultures of cancer cells in liquid without extracellular matrix (ECM) offer in vitro models for metastasising conditions such as those in vessels and effusion. However, liquid culturing is often hindered by cell adhesiveness, which causes large cell clumps. We previously described a liquid culture material, LA717, which prevents nonclonal cell adhesion and subsequent clumping, thus allowing clonal growth of spheroids in an anchorage-independent manner. Here, we examined such liquid culture cancer spheroids for the acquisition of apical-basal polarity, sensitivity to an Akt inhibitor (anticancer drug MK-2206) and interaction with ECM. The spheroids present apical plasma membrane on the surface, which originated from the failure of polarisation at the single-cell stage and subsequent defects in phosphorylated ezrin accumulation at the cell boundary during the first cleavage, failing internal lumen formation. At the multicellular stage, liquid culture spheroids presented bleb-like protrusion on the surface, which was enhanced by the activation of the PI3K/Akt pathway and reduced by PI3K/Akt inhibitors. Liquid culture spheroids exhibited slow proliferation speed and low endogenous pAkt levels compared with gel-cultured spheroids and 2D-cultured cells, explaining the susceptibility to the Akt-inhibiting anticancer drug. Subcutaneous xenografting and in vitro analysis demonstrated low viability and adhesive property of liquid culture spheroids to ECM, while migratory and invasive capacities were comparable with gel-cultured spheroids. These features agree with the low efficacy of circulating tumour spheroids in the settling step of metastasis. This study demonstrates the feature of anchorage-independent spheroids and validates liquid cultures as a useful method in cancer spheroid research.

The label-free separation and culture of tumor cells in a microfluidic biochip

Circulating tumor cells (CTCs) from liquid biopsy have shown a strong correlation to the clinical outcome of cancer patients. The enumeration and cytological analysis of CTCs have attracted increasing efforts for cancer disease management amid immunotherapy and personalized medicine. However, both enumeration and cytological analysis are challenging due to the rarity of CTCs and the lack of integrated solutions for the minimal risk of cell loss in the course of CTC procurement. We report a simple microfluidic chip permitting a one-stop solution for streamlining the on-chip cell separation, capture, immunofluorescence assay and/or in situ culture of isolated cells devoid of risky manual steps. Our results showed effective trapping of single cells, doublets and cell lumps isolated from blood in the same device. On-chip immunostaining revealed normal cell morphology and the characterization of cell expansion uncovered an altered cell growth curve with a reduced lag phase as compared to the conventional culture despite closely matching cell growth rates. The cells were viable and functional for as long as 11 days inside our chip and cell migration was also readily observed, with lumps showing greater aggressiveness than single cells. With these results, we expect promising applications of our one-stop solution for liquid biopsy via CTCs.

Self-Assembled GO Honeycomb Microarray for Selective Cancer Cell Capture and Single Cell Analysis of Proteolytic Expression

Proteolytic enzymes expressed by circulating tumor cells are proved to facilitate their invasion into multiple organs via cleaving natural ECM networks, leading to consequent metastasis colonization and malignant lethality. Recent evidence suggests the rare metastasis initiating cells with higher proteolytic levels among circulating tumor cells (CTCs) may strongly increase the risk of metastasis. Beyond selective CTC capture, the heterogeneity in proteases expression provides a promising indicator for metastasis happening. To this end, the graphene oxide (GO) honeycomb microarray with single CTC matched sizes is fabricated via the self-assembly breath figure approach, which serves as an integrated protocol for selective CTC capture and single-cell analysis of protease activity. Contributing to synergistic effects of structure and chemistry, CTCs can be efficiently isolated and individually trapped in each honeycomb hole. Meanwhile, the crosstalk among CTCs can be erased by blocking direct cell-to-cell contact, which offers promising potentials in the single-cell analysis of protease expression. Integrating specific capture and in situ analysis of single CTCs on GO micropatterned surface is of significant importance in various biological and clinical applications such as cancer diagnostics and cancer therapeutic evaluation.

Inhibition of Angiogenesis by Treatment with Cold Atmospheric Plasma as a Promising Therapeutic Approach in Oncology

Background: Cold atmospheric plasma (CAP) is increasingly used in the field of oncology. Many of the mechanisms of action of CAP, such as inhibiting proliferation, DNA breakage, or the destruction of cell membrane integrity, have been investigated in many different types of tumors. In this regard, data are available from both in vivo and in vitro studies. Not only the direct treatment of a tumor but also the influence on its blood supply play a decisive role in the success of the therapy and the patient’s further prognosis. Whether the CAP influences this process is unknown, and the first indications in this regard are addressed in this study. Methods: Two different devices, kINPen and MiniJet, were used as CAP sources. Human endothelial cell line HDMEC were treated directly and indirectly with CAP, and growth kinetics were performed. To indicate apoptotic processes, caspase-3/7 assay and TUNEL assay were used. The influence of CAP on cellular metabolism was examined using the MTT and glucose assay. After CAP exposure, tube formation assay was performed to examine the capillary tube formation abilities of HDMEC and their migration was messured in separate assays. To investigate in a possible mutagenic effect of CAP treatment, a hypoxanthine-guanine-phosphoribosyl-transferase assay with non malignant cell (CCL-93) line was performed. Results: The direct CAP treatment of the HDMEC showed a robust growth-inhibiting effect, but the indirect one did not. The MMT assay showed an apparent reduction in cell metabolism in the first 24 h after CAP treatment, which appeared to normalize 48 h and 72 h after CAP application. These results were also confirmed by the glucose assay. The caspase 3/7 assay and TUNEL assay showed a significant increase in apoptotic processes in the HDMEC after CAP treatment. These results were independent of the CAP device. Both the migration and tube formation of HDMEC were significant inhibited after CAP-treatment. No malignant effects could be demonstrated by the CAP treatment on a non-malignant cell line.

Circulating tumor cells as Trojan Horse for understanding, preventing, and treating cancer: a critical appraisal

Circulating tumor cells (CTCs) are regarded as harbingers of metastases. Their ability to predict response to therapy, relapse, and resistance to treatment has proposed their value as putative diagnostic and prognostic indicators. CTCs represent one of the zeniths of cancer evolution in terms of cell survival; however, the triggers of CTC generation, the identification of potentially metastatic CTCs, and the mechanisms contributing to their heterogeneity and aggressiveness represent issues not yet fully deciphered. Thus, prior to enabling liquid biopsy applications to reach clinical prime time, understanding how the above mechanistic information can be applied to improve treatment decisions is a key challenge. Here, we provide our perspective on how CTCs can provide mechanistic insights into tumor pathogenesis, as well as on CTC clinical value. In doing so, we aim to (a) describe how CTCs disseminate from the primary tumor, and their link to epithelial-mesenchymal transition (EMT); (b) trace the route of CTCs through the circulation, focusing on tumor self-seeding and the possibility of tertiary metastasis; (c) describe possible mechanisms underlying the enhanced metastatic potential of CTCs; (d) discuss how CTC could provide further information on the tissue of origin, especially in cancer of unknown primary origin. We also provide a comprehensive review of meta-analyses assessing the prognostic significance of CTCs, to highlight the emerging role of CTCs in clinical oncology. We also explore how cell-free circulating tumor DNA (ctDNA) analysis, using a combination of genomic and phylogenetic analysis, can offer insights into CTC biology, including our understanding of CTC heterogeneity and tumor evolution. Last, we discuss emerging technologies, such as high-throughput quantitative imaging, radiogenomics, machine learning approaches, and the emerging breath biopsy. These technologies could compliment CTC and ctDNA analyses, and they collectively represent major future steps in cancer detection, monitoring, and management.

High throughput profiling drug response and apoptosis of single polar cells

The drug response of single polar cells was evaluated via single cell trapping on anisotropic microwells for tumor heterogeneity.

Fibronectin in Cancer: Friend or Foe

The role of fibronectin (FN) in tumorigenesis and malignant progression has been highly controversial. Cancerous FN plays a tumor-suppressive role, whereas it is pro-metastatic and associated with poor prognosis. Interestingly, FN matrix deposited in the tumor microenvironments (TMEs) promotes tumor progression but is paradoxically related to a better prognosis. Here, we justify how FN impacts tumor transformation and subsequently metastatic progression. Next, we try to reconcile and rationalize the seemingly conflicting roles of FN in cancer and TMEs. Finally, we propose future perspectives for potential FN-based therapeutic strategies.

Single Polar Cell Trapping Based on the Breath Figure Method

The ability to research individual cells is important for various biological studies. Currently reported biointerfaces for single-cell analysis can only trap individual cells in random morphologies. Cell polarity is a key factor in cellular functions, and the study of single-cell polarity can facilitate an understanding of cancer metastasis and stem-cell differentiation. For single polar cell trapping, anisotropic honeycomb-structured films were prepared. Elastic poly(1,2-butadiene) honeycomb films with ordered hexagonal pores were first prepared via the breath figure method. Subsequently, the films were subjected to mechanical stretching and fixed via photo-cross-linking under UV light irradiation. This stretched honeycomb structure was then transferred to a polystyrene surface. The resultant anisotropic porous films exhibited excellent capacity for single-cell trapping. Besides contributing to the physical spatial confinement of cells, the trapped single cells exhibited orientation in different polarities. The single polar cell array provided a novel platform for fundamental biological research.

Novel approaches to link apicobasal polarity to cell fate specification

Understanding the development of apicobasal polarity (ABP) is a long-standing problem in biology. The molecular components involved in the development and maintenance of APB have been largely identified and are known to have ubiquitous roles across organisms. Our knowledge of the functional consequences of ABP establishment and maintenance is far less comprehensive. Recent studies using novel experimental approaches and cellular models have revealed a growing link between ABP and the genetic program of cell lineage. This mini-review describes some of the most recent advances in this new field, highlighting examples from Caenorhabditis elegans and mouse embryos, human pluripotent stem cells, and epithelial cells. We also speculate on the most interesting and challenging avenues that can be explored.

Tunneling nanotube-mediated intercellular vesicle and protein transfer in the stroma-provided imatinib resistance in chronic myeloid leukemia cells

Intercellular communication within the bone marrow niche significantly promotes leukemogenesis and provides protection of leukemic cells from therapy. Secreted factors, intercellular transfer of mitochondria and the receptor-ligand interactions have been shown as mediators of this protection. Here we report that tunneling nanotubes (TNTs)-long, thin membranous structures, which have been identified as a novel mode of intercellular cross-talk-are formed in the presence of stroma and mediate transfer of cellular vesicles from stroma to leukemic cells. Importantly, transmission of vesicles via TNTs from stromal cells increases resistance of leukemic cells to the tyrosine kinase inhibitor, imatinib. Using correlative light-electron microscopy and electron tomography we show that stromal TNTs contain vesicles, provide membrane continuity with the cell bodies and can be open-ended. Moreover, trans-SILAC studies to reveal the non-autonomous proteome showed that specific sets of proteins are transferred together with cellular vesicles from stromal to leukemic cells, with a potential role in survival and adaptation. Altogether, our findings provide evidence for the biological role of the TNT-mediated vesicle exchange between stromal and leukemic cells, implicating the direct vesicle and protein transfer in the stroma-provided protection of leukemic cells.

The role of polarisation of circulating tumour cells in cancer metastasis

Metastasis is the spread of cancer cells from a primary tumour to a distant site of the body. Metastasising tumour cells have to survive and readjust to different environments, such as heterogeneous solid tissues and liquid phase in lymph- or blood circulation, which they achieve through a high degree of plasticity that renders them adaptable to varying conditions. One defining characteristic of the metastatic process is the transition of tumour cells between different polarised phenotypes, ranging from differentiated epithelial polarity to migratory front-rear polarity. Here, we review the polarisation types adopted by tumour cells during the metastatic process and describe the recently discovered single-cell polarity in liquid phase observed in circulating tumour cells. We propose that single-cell polarity constitutes a mode of polarisation of the cell cortex that is uncoupled from the intracellular polarisation machinery, which distinguishes single-cell polarity from other types of polarity identified so far. We discuss how single-cell polarity can contribute to tumour metastasis and the therapeutic potential of this new discovery.

From NASH to HCC: current concepts and future challenges

Caloric excess and sedentary lifestyle have led to a global epidemic of obesity and metabolic syndrome. The hepatic consequence of metabolic syndrome and obesity, nonalcoholic fatty liver disease (NAFLD), is estimated to affect up to one-third of the adult population in many developed and developing countries. This spectrum of liver disease ranges from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Owing to the high prevalence of NAFLD, especially in industrialized countries but also worldwide, and the consequent burden of progressive liver disease, there is mounting epidemiological evidence that NAFLD has rapidly become a leading aetiology underlying many cases of hepatocellular carcinoma (HCC). In this Review, we discuss NAFLD-associated HCC, including its epidemiology, the key features of the hepatic NAFLD microenvironment (for instance, adaptive and innate immune responses) that promote hepatocarcinogenesis and the management of HCC in patients with obesity and associated metabolic comorbidities. The challenges and future directions of research will also be discussed, including clinically relevant biomarkers for early detection, treatment stratification and monitoring as well as approaches to therapies for both prevention and treatment in those at risk or presenting with NAFLD-associated HCC.

Predicting Collective Migration of Cell Populations Defined by Varying Repolarization Dynamics

Collective migration of heterogeneous cell populations is an essential aspect of fundamental biological processes, including morphogenesis, wound healing, and tumor invasion. Through experiments and modeling, it has been shown that cells attain front-rear polarity, generate forces, and form adhesions to migrate. However, it remains unclear how the ability of individual cells in a population to dynamically repolarize themselves into new directions could regulate the collective response. We present a vertex-based model in which each deformable cell randomly chooses a new polarization direction after every defined time interval, elongates, proportionally generates forces, and causes collective migration. Our simulations predict that cell types that repolarize at longer time intervals attain more elongated shapes, migrate faster, deform the cell sheet, and roughen the leading edge. By imaging collectively migrating epithelial cell monolayers at high temporal resolution, we found longer repolarization intervals and elongated shapes of cells at the leading edge compared to those within the monolayer. Based on these experimental measurements and simulations, we defined aggressive mutant leader cells by long repolarization interval and minimal intercellular contact. The cells with frequent and random repolarization were defined as normal cells. In simulations with uniformly dispersed leader cells in a normal cell population at a 1:10 ratio, the resulting migration and deformation of the heterogeneous cell sheet remained low. However, when the 10% mutant leaders were placed only at the leading edge, we predicted a rise in the migration of an otherwise normal cell sheet. Our model predicts that a repolarization-based definition of leader cells and their placement within a healthy population can generate myriad modes of collective cell migration, which can enhance our understanding of collective cell migration in disease and development.

Liquid biopsy for liver diseases

With the growing number of novel therapeutic approaches for liver diseases, significant research efforts have been devoted to the development of liquid biopsy tools for precision medicine. This can be defined as non-invasive reliable biomarkers that can supplement and eventually replace the invasive liver biopsy for diagnosis, disease stratification and monitoring of response to therapeutic interventions. Similarly, detection of liver cancer at an earlier stage of the disease, potentially susceptible to curative resection, can be critical to improve patient survival. Circulating extracellular vesicles, nucleic acids (DNA and RNA) and tumour cells have emerged as attractive liquid biopsy candidates because they fulfil many of the key characteristics of an ideal biomarker. In this review, we summarise the currently available information regarding these promising and potential transformative tools, as well as the issues still needed to be addressed for adopting various liquid biopsy approaches into clinical practice. These studies may pave the way to the development of a new generation of reliable, mechanism-based disease biomarkers.

Single-Cell Imaging of Metastatic Potential of Cancer Cells

Molecular imaging of metastatic “potential” is an unvanquished challenge. To engineer biosensors that can detect and measure the metastatic “potential” of single living cancer cells, we carried out a comprehensive analysis of the pan-cancer phosphoproteome to search for actin remodelers required for cell migration, which are enriched in cancers but excluded in normal cells. Only one phosphoprotein emerged, tyr-phosphorylated CCDC88A (GIV/Girdin), a bona fide metastasis-related protein across a variety of solid tumors. We designed multi-modular biosensors that are partly derived from GIV, and because GIV integrates prometastatic signaling by multiple oncogenic receptors, we named them “‘integrators of metastatic potential (IMP).” IMPs captured the heterogeneity of metastatic potential within primary lung and breast tumors at steady state, detected those few cells that have acquired the highest metastatic potential, and tracked their enrichment during metastasis. These findings provide proof of concept that IMPs can measure the diversity and plasticity of metastatic potential of tumor cells in a sensitive and unbiased way.

•

Phosphoproteomes of cancers predicted a putative metastasis-specific phosphoevent

•

FRET-based biosensor designed to assess this phosphoevent in living cells

•

Biosensor tracks the diversity and plasticity of metastatic potential of cancer cells

•

These sensors could direct drug efficacy testing against the most sinister cancer cells

SOX2, a stemness gene, induces progression of NSCLC A549 cells toward anchorage-independent growth and chemoresistance to vinblastine

Background

Non-small cell lung cancer (NSCLC) is difficult to treat successfully. This intractability is mainly due to the cancer progressing through invasion, metastasis, chemotherapeutic resistance and relapse. Stemness has been linked to the various steps of cancer progression in a variety of tumors, yet little is known regarding its role in NSCLC.

Purpose

In this study, we sought to determine the role of SOX2, a master regulator of pluripotency, in the growth of extracellular matrix (ECM)-detached cells during cancer progression.

Methods

We established a three-dimensional (3D) Poly-2-hydroxyethyl methacrylate (poly-HEMA) culture of lung adenocarcinoma (LUAD) A549 cells as an ECM-detached cell growth model and examined the role of stemness genes using siRNA and small molecule inhibitor in comparison to standard two dimensional (2D) culture.

Results

In poly-HEMA culture, A549 cells formed substratum-detached spheroids with characteristics of intermediate epithelial to mesenchymal transition (EMT) and exhibited greater expression of SOX2 than did control 2D cells. Knockdown of SOX2 markedly suppressed the growth of A549 cell aggregates in poly-HEMA culture conditions and furthermore increased their sensitivity to the anticancer drug vinblastine with concomitant downregulation of the activity of the anti-apoptotic AKT kinase. Interestingly, a small molecule, RepSox, which replaces SOX2, stimulated A549 cell growth in poly-HEMA 3D culture condition.

Conclusion

Our findings strongly indicate that SOX2 contributes to anchorage-independent growth and chemoresistance via its downstream signaling mediator AKT kinase during the disease progression of NSCLC. SOX2 may therefore be an invaluable therapeutic target of NSCLC.

The biochemistry, signalling and disease relevance of RYK and other WNT-binding receptor tyrosine kinases

The receptor tyrosine kinases (RTKs) are a well-characterized family of growth factor receptors that have central roles in human disease and are frequently therapeutically targeted. The RYK, ROR, PTK7 and MuSK subfamilies make up an understudied subset of WNT-binding RTKs. Numerous developmental, stem cell and pathological roles of WNTs, in particular WNT5A, involve signalling via these WNT receptors. The WNT-binding RTKs have highly context-dependent signalling outputs and stimulate the β-catenin-dependent, planar cell polarity and/or WNT/Ca²⁺ pathways. RYK, ROR and PTK7 members have a pseudokinase domain in their intracellular regions. Alternative signalling mechanisms, including proteolytic cleavage and protein scaffolding functions, have been identified for these receptors. This review explores the structure, signalling, physiological and pathological roles of RYK, with particular attention paid to cancer and the possibility of therapeutically targeting RYK. The other WNT-binding RTKs are compared with RYK throughout to highlight the similarities and differences within this subset of WNT receptors.

Manipulating cell fate: dynamic control of cell behaviors on functional platforms

We review the recent advances and new horizons in the dynamic control of cell behaviors on functional platforms and their applications.