Neuropilin-1-Targeted Nanomedicine for Spatiotemporal Tumor Suppression through Photodynamic Vascular Damage and Antiangiogenesis.

Antiangiogenic therapy is an effective way to disrupt nutrient supply and starve tumors, but it is restricted by poor efficacy and negative feedback-induced tumor relapse. In this study, a neuropilin-1 (NRP-1)-targeted nanomedicine (designated as FPPT@Axi) is reported for spatiotemporal tumor suppression by combining photodynamic therapy (PDT) with antiangiogenesis. In brief, FPPT@Axi is prepared by utilizing an NRP-1-targeting chimeric peptide (Fmoc-K(PpIX)-PEG8-TKPRR) to encapsulate the antiangiogenic drug Axitinib (Axi). Importantly, the NRP-1-mediated targeting property enables FPPT@Axi to selectively concentrate at vascular endothelial and breast cancer cells, facilitating the production of reactive oxygen species (ROS) in situ for specific vascular disruption and enhanced cell apoptosis under light stimulation. Moreover, the codelivered Axi can further inhibit vascular endothelial growth factor receptor (VEGFR) to impair the negative feedback of PDT-induced tumor neovascularization. Consequently, FPPT@Axi spatiotemporally restrains the tumor growth through blocking angiogenesis, destroying tumor vessels, and inducing tumor apoptosis. Such an NRP-1-mediated targeting codelivery system sheds light on constructing an appealing candidate with translational potential by using clinically approved PDT and chemotherapy.

Breaking Physical Barrier of Fibrotic Breast Cancer for Photodynamic Immunotherapy by Remodeling Tumor Extracellular Matrix and Reprogramming Cancer-Associated Fibroblasts.

Cancer-associated fibroblasts (CAFs) assist in breast cancer (BRCA) invasion and immune resistance by overproduction of extracellular matrix (ECM). Herein, we develop FPC@S, a photodynamic immunomodulator that targets the ECM, to improve the photodynamic immunotherapy for fibrotic BRCA. FPC@S combines a tumor ECM-targeting peptide, a photosensitizer (protoporphyrin IX) and an antifibrotic drug (SIS3). After anchoring to the ECM, FPC@S causes ECM remodeling and BRCA cell death by generating reactive oxygen species (ROS) in situ. Interestingly, the ROS-mediated ECM remodeling can normalize the tumor blood vessel to improve hypoxia and in turn facilitate more ROS production. Besides, upon the acidic tumor microenvironment, FPC@S will release SIS3 for reprograming CAFs to reduce their activity but not kill them, thus inhibiting fibrosis while preventing BRCA metastasis. The natural physical barrier formed by the dense ECM is consequently eliminated in fibrotic BRCA, allowing the drugs and immune cells to penetrate deep into tumors and have better efficacy. Furthermore, FPC@S can stimulate the immune system and effectively suppress primary, distant and metastatic tumors by combining with immune checkpoint blockade therapy. This study provides different insights for the development of fibrotic tumor targeted delivery systems and exploration of synergistic immunotherapeutic mechanisms against aggressive BRCA.

Tumor Homing Chimeric Peptide Rhomboids to Improve Photodynamic Performance by Inhibiting Therapy-Upregulated Cyclooxygenase-2.

Negative therapeutic feedback of inflammation would extensively attenuate the antitumor effect of photodynamic therapy (PDT). In this work, tumor homing chimeric peptide rhomboids (designated as NP-Mel) are fabricated to improve photodynamic performance by inhibiting PDT-upregulated cyclooxygenase-2 (COX-2). The hydrophobic photosensitizer of protoporphyrin IX (PpIX) and palmitic acid are conjugated onto the neuropilin receptors (NRPs) targeting peptide motif (CGNKRTR) to obtain tumor homing chimeric peptide (Palmitic-K(PpIX)CGNKRTR), which can encapsulate the COX-2 inhibitor of meloxicam. The well dispersed NP-Mel not only improves the drug stability and reactive oxygen species (ROS) production ability, but also increase the breast cancer targeted drug delivery to intensify the PDT effect. In vitro and in vivo studies verify that NP-Mel will decrease the secretion of prostaglandin E2 (PGE2) after PDT treatment, inducing the downregulation of IL-6 and TNF-α expressions to suppress PDT induced inflammation. Ultimately, an improved PDT performance of NP-Mel is achieved without inducing obvious systemic toxicity, which might inspire the development of sophisticated nanomedicine in consideration of the feedback induced therapeutic resistance.

TRIM28-mediated nucleocapsid protein SUMOylation enhances SARS-CoV-2 virulence.

Viruses, as opportunistic intracellular parasites, hijack the cellular machinery of host cells to support their survival and propagation. Numerous viral proteins are subjected to host-mediated post-translational modifications. Here, we demonstrate that the SARS-CoV-2 nucleocapsid protein (SARS2-NP) is SUMOylated on the lysine 65 residue, which efficiently mediates SARS2-NP's ability in homo-oligomerization, RNA association, liquid-liquid phase separation (LLPS). Thereby the innate antiviral immune response is suppressed robustly. These roles can be achieved through intermolecular association between SUMO conjugation and a newly identified SUMO-interacting motif in SARS2-NP. Importantly, the widespread SARS2-NP R203K mutation gains a novel site of SUMOylation which further increases SARS2-NP's LLPS and immunosuppression. Notably, the SUMO E3 ligase TRIM28 is responsible for catalyzing SARS2-NP SUMOylation. An interfering peptide targeting the TRIM28 and SARS2-NP interaction was screened out to block SARS2-NP SUMOylation and LLPS, and consequently inhibit SARS-CoV-2 replication and rescue innate antiviral immunity. Collectively, these data support SARS2-NP SUMOylation is critical for SARS-CoV-2 virulence, and therefore provide a strategy to antagonize SARS-CoV-2.

Clinical value of ankle flexion and extension exercises combined with a psychological intervention in knee osteoarthritis.

BACKGROUND: Considering the limited effectiveness of clinical interventions for knee osteoarthritis (KOA), it is necessary to continue to explore appropriate and effective treatment strategies to improve the condition of KOA patients. AIM: To clarify the influence of ankle flexion and extension exercises combined with a psychological intervention on the psychological status and activities of daily living (ADLs) of patients with KOA. METHODS: The research participants were 116 KOA patients admitted to The First Affiliated Hospital of Guizhou University of Traditional Chinese Medicine between May 2019 and May 2022, including 54 patients receiving routine treatment, care and psychological intervention (control group) and 62 patients additionally treated with ankle flexion and extension exercises (research group). The two groups were comparatively analyzed in terms of psychological status (Self-rating Anxiety/Depression Scale, SDS/SAS), ADLs, knee joint function (Lysholm Knee Scoring Scale), pain (Visual Analog Scale, VAS), fatigue (Multidimensional Fatigue Inventory, MFI), and quality of life (QoL; Short-Form 36 Item Health Survey, SF-36). RESULTS: After evaluation, it was found that the postinterventional SDS, SAS, VAS, and MFI scores in the research group were significantly reduced compared with the baseline (before the intervention) values and those of the control group, while the postinterventional Lysholm, ADL and SF-36 scores were markedly elevated. CONCLUSION: Therefore, ankle flexion and extension exercises are highly effective in easing negative psychological status, enhancing ADLs, daily living ability, knee joint function and QoL, and relieving pain and fatigue in KOA patients, thus warranting clinical promotion.

Self-Delivery Photodynamic Re-educator Enhanced Tumor Treatment by Inducing Immunogenic Cell Death and Improving Immunosuppressive Microenvironments.

Immunotherapy is known to be a promising strategy in the clinical treatment of malignant tumors, but it has received generally low response rates in various tumors because of the poor immunogenicity and multiple immunosuppressive microenvironments. A self-delivery photodynamic re-educator, denoted as CCXB, is synthesized through the self-assembly of chlorine e6 (Ce6) and celecoxib (CXB). As a carrier-free nanomedicine, CCXB shows a high drug loading rate, improved water stability, superior cellular uptake, and tumor accumulation capability. In comparison with free Ce6, CCXB triggers much stronger photodynamic therapy (PDT) to reduce the proliferation of breast cancer cells and activates robust immune responses via the induction of immunogenic cell death (ICD). Better yet, CXB-mediated cyclooxygenase 2 (COX-2) inhibition can decrease the level of synthesis of prostaglandin E2 (PGE2) to further improve immunosuppressive microenvironments. With the increase of cytotoxic T lymphocytes (CTLs) and decrease of regulatory T cells (Tregs) in tumor, in vivo antitumor immunity is significantly amplified to inhibit the metastasis of breast cancer. This study sheds light on developing drug codelivery systems with collaborative mechanisms for immunotherapy of metastatic tumors.

Deubiquitylating Enzymes in Cancer and Immunity.

Deubiquitylating enzymes (DUBs) maintain relative homeostasis of the cellular ubiquitome by removing the post-translational modification ubiquitin moiety from substrates. Numerous DUBs have been demonstrated specificity for cleaving a certain type of ubiquitin linkage or positions within ubiquitin chains. Moreover, several DUBs perform functions through specific protein-protein interactions in a catalytically independent manner, which further expands the versatility and complexity of DUBs' functions. Dysregulation of DUBs disrupts the dynamic equilibrium of ubiquitome and causes various diseases, especially cancer and immune disorders. This review summarizes the Janus-faced roles of DUBs in cancer including proteasomal degradation, DNA repair, apoptosis, and tumor metastasis, as well as in immunity involving innate immune receptor signaling and inflammatory and autoimmune disorders. The prospects and challenges for the clinical development of DUB inhibitors are further discussed. The review provides a comprehensive understanding of the multi-faced roles of DUBs in cancer and immunity.

Feedback-Elevated Antitumor Amplifier of Self-Delivery Nanomedicine by Suppressing Photodynamic Therapy-Caused Inflammation.

Inflammation activation is accompanied by tumor growth, migration, and differentiation. Photodynamic therapy (PDT) can trigger an inflammatory response to cause negative feedback of tumor inhibition. In this paper, a feedback-elevated antitumor amplifier is developed by constructing self-delivery nanomedicine for PDT and cascade anti-inflammation therapy. Based on the photosensitizer chlorin e6 (Ce6) and COX-2 inhibitor indomethacin (Indo), the nanomedicine is prepared via molecular self-assembly technology without additional drug carriers. It is exciting that the optimized nanomedicine (designated as CeIndo) possesses favorable stability and dispersibility in the aqueous phase. Moreover, the drug delivery efficiency of CeIndo is significantly improved, which could be effectively accumulated at the tumor site and internalized by tumor cells. Importantly, CeIndo not only exhibits a robust PDT efficacy on tumor cells but also drastically decreases the PDT-induced inflammatory response in vivo, resulting in feedback-elevated tumor inhibition. By virtue of the synergistic effect of PDT and cascade inflammation suppression, CeIndo tremendously reduces tumor growth and leads to a low side effect. This study presents a paradigm for the development of codelivery nanomedicine for enhanced tumor therapy through inflammation suppression.

Carrier-Free Nano-PROTACs to Amplify Photodynamic Therapy Induced DNA Damage through BRD4 Degradation.

Therapy-induced DNA damage is the most common strategy to inhibit tumor cell proliferation, but the therapeutic efficacy is limited by DNA repair machinery. Carrier-free nanoproteolysis targeting chimeras (PROTACs), designed as SDNpros, have been developed to enhance photodynamic therapy (PDT) by blocking the DNA damage repair pathway through BRD4 degradation. Specifically, SDNpros are constructed through noncovalent interactions between the photosensitizer of chlorine e6 (Ce6) and PROTACs of BRD4 degrader (dBET57) via self-assembly. SDNpro has favorable dispersibility and a uniform nanosize distribution without drug excipients. Upon light irradiation, SDNpro produces abundant reactive oxygen species (ROS) to induce DNA oxidative damage. Meanwhile, the DNA repair pathway would be interrupted by the concurrent degradation of BRD4, which could intensify the oxidative DNA damage and elevate PDT efficiency. Beneficially, SDNpro suppresses tumor growth and avoids systemic side effects, providing a promising strategy to promote the clinical translation of PROTACs for tumor treatment.

Paraptosis Inducer to Effectively Trigger Immunogenic Cell Death for Metastatic Tumor Immunotherapy with IDO Inhibition.

Paraptosis is characterized by the extensive vacuolization of endoplasmic reticulum (ER) and mitochondria, which will cause the release of damage-associated molecular patterns to promote immunogenic cell death (ICD). However, the tumor can develop an immunosuppressive microenvironment to affect the ICD activation for the purpose of immune escape. Herein, a paraptosis inducer (CMN) is constructed to amplify the ICD effect for efficient immunotherapy by inhibiting the activity of indoleamine 2,3-dioxygenase (IDO). Initially, CMN is prepared by the assembly of copper ions (Cu2+), morusin (MR), and IDO inhibitor (NLG919) through noncovalent interactions. Without the need for extra drug carriers, CMN possesses very high drug contents and exhibits a favorable GSH responsiveness for disassembly. Subsequently, the released MR can trigger paraptosis to cause extensive vacuolization of ER and mitochondria, contributing to activating ICD for immunotherapy. Moreover, NLG919 would inhibit IDO to remodel the tumor microenvironment and promote the activation of cytotoxic T cells, leading to an intensive antitumor immunity. Abundant in vivo studies indicate that CMN is superior in suppressing the proliferations of not only primary tumor but also metastatic and rechallenged tumors. Such a GSH-responsive paraptosis inducer might provide a promising strategy to trigger ICD and enhance tumor immunotherapy.

M2 macrophages mediate fibrotic scar formation in the early stages after cerebral ischemia in rats.

In the central nervous system, the formation of fibrotic scar after injury inhibits axon regeneration and promotes repair. However, the mechanism underlying fibrotic scar formation and regulation remains poorly understood. M2 macrophages regulate fibrotic scar formation after injury to the heart, lung, kidney, and central nervous system. However, it remains to be clarified whether and how M2 macrophages regulate fibrotic scar formation after cerebral ischemia injury. In this study, we found that, in a rat model of cerebral ischemia induced by middle cerebral artery occlusion/reperfusion, fibrosis and macrophage infiltration were apparent in the ischemic core in the early stage of injury (within 14 days of injury). The number of infiltrated macrophages was positively correlated with fibronectin expression. Depletion of circulating monocyte-derived macrophages attenuated fibrotic scar formation. Interleukin 4 (IL4) expression was strongly enhanced in the ischemic cerebral tissues, and IL4-induced M2 macrophage polarization promoted fibrotic scar formation in the ischemic core. In addition, macrophage-conditioned medium directly promoted fibroblast proliferation and the production of extracellular matrix proteins in vitro. Further pharmacological and genetic analyses showed that sonic hedgehog secreted by M2 macrophages promoted fibrogenesis in vitro and in vivo, and that this process was mediated by secretion of the key fibrosis-associated regulatory proteins transforming growth factor beta 1 and matrix metalloproteinase 9. Furthermore, IL4-afforded functional restoration on angiogenesis, cell apoptosis, and infarct volume in the ischemic core of cerebral ischemia rats were markedly impaired by treatment with an sonic hedgehog signaling inhibitor, paralleling the extent of fibrosis. Taken together, our findings show that IL4/sonic hedgehog/transforming growth factor beta 1 signaling targeting macrophages regulates the formation of fibrotic scar and is a potential therapeutic target for ischemic stroke.

Self-delivery biomedicine for enhanced photodynamic therapy by feedback promotion of tumor autophagy.

Reactive oxygen species (ROS) generated during photodynamic therapy (PDT) can induce autophagy to protect tumor cell from PDT-induced apoptosis. In this work, a self-delivery autophagy regulator (designated as CeCe) is developed for autophagy promotion sensitized PDT against tumor. Briefly, CeCe is prepared by the assembly of a photosensitizer of chlorin e6 (Ce6) and autophagy promoter of celastrol. By virtue of intermolecular interactions, Ce6 and celastrol are able to self-assemble into nanomedicine with great photodynamic performance and autophagy regulation capacity. Under light irradiation, CeCe would produce ROS in tumor cells to amplify the oxidative stress and promote cell autophagy. As a result, CeCe exhibits an enhanced photo toxicity by inducing autophagic cell death. In vivo experiments indicate that CeCe can predominantly accumulate in tumor tissue for a robust PDT. Moreover, CeCe has a superior therapeutic efficiency compared to monotherapy and combined treatment of Ce6 and celastrol, suggesting a synergistic antitumor effect of PDT and autophagy promotion. This self-delivery nanomedicine may advance the development of the co-delivery nanoplatform to improve the antitumor efficacy of PDT by promoting autophagy. STATEMENT OF SIGNIFICANCE: Autophagy is a "double-edged sword" in cellular homeostasis and metabolism, which can promote tumor progression but also induce an unknown impact on tumor inhibition. In this work, a self-delivery autophagy regulator (designated as CeCe) was developed for autophagy promotion sensitized photodynamic therapy (PDT). By virtue of intermolecular interactions, Ce6 and celastrol were found to self-assemble into stable CeCe without drug excipients, which exhibited great photodynamic performance and autophagy regulation capacity. In vitro and in vivo findings demonstrated a superior tumor suppression ability of CeCe over the monotherapy as well as the combined treatment of Ce6 and celastrol, suggesting a synergistic antitumor efficacy by PDT and autophagy promotion.

Cascade Immune Activation of Self-Delivery Biomedicine for Photodynamic Immunotherapy Against Metastatic Tumor.

Photodynamic therapy (PDT) can generate reactive oxygen species (ROS) to cause cell apoptosis and induce immunogenic cell death (ICD) to activate immune response, becoming a promising antitumor modality. However, the overexpressions of indoleamine 2,3-dioxygenase (IDO) and programmed cell death ligand 1 (PD-L1) on tumor cells would reduce cytotoxic T cells infiltration and inhibit the immune activation. In this paper, a simple but effective nanosystem is developed to solve these issues for enhanced photodynamic immunotherapy. Specifically, it has been constructed a self-delivery biomedicine (CeNB) based on photosensitizer chlorine e6 (Ce6), IDO inhibitor (NLG919), and PD1/PDL1 blocker (BMS-1) without the need for extra excipients. Of note, CeNB possesses fairly high drug content (nearly 100%), favorable stability, and uniform morphology. More importantly, CeNB-mediated IDO inhibition and PD1/PDL1 blockade greatly improve the immunosuppressive tumor microenvironments to promote immune activation. The PDT of CeNB not only inhibits tumor proliferation but also induces ICD response to activate immunological cascade. Ultimately, self-delivery CeNB tremendously suppresses the tumor growth and metastasis while leads to a minimized side effect. Such simple and effective antitumor strategy overcomes the therapeutic resistance against PDT-initiated immunotherapy, suggesting a potential for metastatic tumor treatment in clinic.

Ultrasonographic evaluation of the rete testis thickness: a promising approach to differentiate obstructive from nonobstructive azoospermia / 亚洲男科学杂志(英文版)

This study aimed to evaluate the ability of rete testis thickness (RTT) and testicular shear wave elastography (SWE) to differentiate obstructive azoospermia (OA) from nonobstructive azoospermia (NOA). We assessed 290 testes of 145 infertile males with azoospermia and 94 testes of 47 healthy volunteers at Shanghai General Hospital (Shanghai, China) between August 2019 and October 2021. The testicular volume (TV), SWE, and RTT were compared among patients with OA and NOA and healthy controls. The diagnostic performances of the three variables were evaluated using the receiver operating characteristic curve. The TV, SWE, and RTT in OA differed significantly from those in NOA (all P ≤ 0.001) but were similar to those in healthy controls. Males with OA and NOA were similar at TVs of 9-11 cm 3 ( P = 0.838), with sensitivity, specificity, Youden index, and area under the curve of 50.0%, 84.2%, 0.34, and 0.662 (95% confidence interval [CI]: 0.502-0.799), respectively, for SWE cut-off of 3.1 kPa; and 94.1%, 79.2%, 0.74, and 0.904 (95% CI: 0.811-0.996), respectively, for RTT cut-off of 1.6 mm. The results showed that RTT performed significantly better than SWE in differentiating OA from NOA in the TV overlap range. In conclusion, ultrasonographic RTT evaluation proved a promising diagnostic approach to differentiate OA from NOA, particularly in the TV overlap range.

Photodynamic Therapy Initiated Ferrotherapy of Self-Delivery Nanomedicine to Amplify Lipid Peroxidation via GPX4 Inactivation.

Lipid peroxide (LPO) is the hallmark of ferroptosis, which is a promising antitumor modality for its unique advantages. However, a cellular defense system would weaken the antitumor efficacy of ferrotherapy. Herein, a GPX4 inhibitor of ML162 and a photosensitizer of chlorine e6 (Ce6) are used to prepare the self-delivery nanomedicine (C-ML162) through hydrophobic and electrostatic interactions to enhance ferroptosis by photodynamic therapy (PDT). Specifically, carrier-free C-ML162 improves the solubility, stability, and cellular uptake of antitumor agents. Upon light irradiation, the internalized C-ML162 generates large amounts of reactive oxygen species (ROS) to oxidize cellular unsaturated lipid into LPO. More importantly, C-ML162 can directly inactivate GPX4 to enhance the accumulation of toxic LPO, inducing ferroptotic cell death. Additionally, C-ML162 is capable of accumulating at a tumor site for effective treatment. This self-delivery system to amplify lipid peroxidation via GPX4 inactivation for PDT initiated ferrotherapy might provide an appealing strategy against malignancies.

A self-delivery photodynamic sensitizer for enhanced DNA damage by PARP inhibition.

Tumor cells activate DNA repair pathways to combat the oxidative damage induced by reactive oxygen species (ROS), contributing to their resistance to photodynamic therapy (PDT). Herein, a self-delivery photodynamic sensitizer is developed to enhance oxidative damage by blocking the DNA repair pathway through poly(ADP-ribose) polymerase (PARP) inhibition. Specifically, the photodynamic sensitizer (CeOla) is constructed based on the self-assembly of the photosensitizer chlorine e6 (Ce6) and the PARP inhibitor olaparib (Ola). Of note is that carrier free CeOla has a high drug content and favorable water stability, which could be effectively internalized by tumor cells for robust PDT upon light irradiation. Moreover, CeOla could inhibit the activation of PARP, promote the upregulation of γ-H2AX and reduce the expression of Rad51, thereby blocking the DNA repair pathway to sensitize tumor cells for PDT. As a consequence, the self-delivery CeOla greatly promotes the tumor cell apoptosis and shows a high antitumor performance with low side effects. It serves as a novel platform for the development of self-delivery nanomedicine to overcome oxidative resistance in tumor treatment.

Emerging Implications of Phase Separation in Cancer.

In eukaryotic cells, biological activities are executed in distinct cellular compartments or organelles. Canonical organelles with membrane-bound structures are well understood. Cells also inherently contain versatile membrane-less organelles (MLOs) that feature liquid or gel-like bodies. A biophysical process termed liquid-liquid phase separation (LLPS) elucidates how MLOs form through dynamic biomolecule assembly. LLPS-related molecules often have multivalency, which is essential for low-affinity inter- or intra-molecule interactions to trigger phase separation. Accumulating evidence shows that LLPS concentrates and organizes desired molecules or segregates unneeded molecules in cells. Thus, MLOs have tunable functional specificity in response to environmental stimuli and metabolic processes. Aberrant LLPS is widely associated with several hallmarks of cancer, including sustained proliferative signaling, growth suppressor evasion, cell death resistance, telomere maintenance, DNA damage repair, etc. Insights into the molecular mechanisms of LLPS provide new insights into cancer therapeutics. Here, the current understanding of the emerging concepts of LLPS and its involvement in cancer are comprehensively reviewed.

OVOL1 inhibits breast cancer cell invasion by enhancing the degradation of TGF-ß type I receptor.

Ovo-like transcriptional repressor 1 (OVOL1) is a key mediator of epithelial lineage determination and mesenchymal-epithelial transition (MET). The cytokines transforming growth factor-ß (TGF-ß) and bone morphogenetic proteins (BMP) control the epithelial-mesenchymal plasticity (EMP) of cancer cells, but whether this occurs through interplay with OVOL1 is not known. Here, we show that OVOL1 is inversely correlated with the epithelial-mesenchymal transition (EMT) signature, and is an indicator of a favorable prognosis for breast cancer patients. OVOL1 suppresses EMT, migration, extravasation, and early metastatic events of breast cancer cells. Importantly, BMP strongly promotes the expression of OVOL1, which enhances BMP signaling in turn. This positive feedback loop is established through the inhibition of TGF-ß receptor signaling by OVOL1. Mechanistically, OVOL1 interacts with and prevents the ubiquitination and degradation of SMAD family member 7 (SMAD7), which is a negative regulator of TGF-ß type I receptor stability. Moreover, a small-molecule compound 6-formylindolo(3,2-b)carbazole (FICZ) was identified to activate OVOL1 expression and thereby antagonizing (at least in part) TGF-ß-mediated EMT and migration in breast cancer cells. Our results uncover a novel mechanism by which OVOL1 attenuates TGF-ß/SMAD signaling and maintains the epithelial identity of breast cancer cells.

Establishment of Embryonic Zebrafish Xenograft Assays to Investigate TGF-ß Family Signaling in Human Breast Cancer Progression.

Transforming growth factor-ß (TGF-ß) family members have pivotal functions in controlling breast cancer progression, acting not only on cancer cells but also on other cells within the tumor microenvironment. Here we describe embryonic zebrafish xenograft assays to investigate how TGF-ß family signaling controls breast cancer cell intravasation, extravasation and regulates tumor angiogenesis. Fluorescently mCherry-labeled breast cancer cells are injected in the perivitelline space or Duct of Cuvier of Tg (fli:EGFP) transgenic Casper zebrafish embryos, in which the zebrafish express enhanced green fluorescent protein in the entire vasculature. The dynamic responses of migratory and invasive human cancer cells, and the induction of new blood vessel formation by the cancer cells in zebrafish host, are visualized using a fluorescent microscope. These assays provide efficient, reliable, low-cost models to investigate the effect of (epi)genetic modulators and pharmacological compounds that perturb the activity of TGF-ß family signaling components on breast cancer cell metastasis and angiogenesis.