Ultrasound molecular imaging as a non-invasive companion diagnostic for netrin-1 interference therapy in breast cancer

Netrin-1 signaling pathway mechanisms in neurodegenerative diseases

Netrin-1 and its receptors play crucial roles in inducing axonal growth and neuronal migration during neuronal development. Their profound impacts then extend into adulthood to encompass the maintenance of neuronal survival and synaptic function. Increasing amounts of evidence highlight several key points: (1) Diminished Netrin-1 levels exacerbate pathological progression in animal models of Alzheimer's disease and Parkinson's disease, and potentially, similar alterations occur in humans. (2) Genetic mutations of Netrin-1 receptors increase an individuals' susceptibility to neurodegenerative disorders. (3) Therapeutic approaches targeting Netrin-1 and its receptors offer the benefits of enhancing memory and motor function. (4) Netrin-1 and its receptors show genetic and epigenetic alterations in a variety of cancers. These findings provide compelling evidence that Netrin-1 and its receptors are crucial targets in neurodegenerative diseases. Through a comprehensive review of Netrin-1 signaling pathways, our objective is to uncover potential therapeutic avenues for neurodegenerative disorders.

The intersection of the nervous system and breast cancer

Breast cancer (BC) represents a paradigm of heterogeneity, manifesting as a spectrum of molecular subtypes with divergent clinical trajectories. It is fundamentally characterized by the aberrant proliferation of malignant cells within breast tissue, a process modulated by a myriad of factors that govern its progression. Recent endeavors outline the interplay between BC and the nervous system, illuminate the complex symbiosis between neural structures and neoplastic cells, and elucidate nerve dependence as a cornerstone of BC progression. This includes the neural modulations on immune response, neurovascular formation, and multisystem interactions. Such insights have unveiled the critical impact of neural elements on tumor dynamics and patient prognosis. This revelation beckons a deeper exploration into the neuro-oncological interface, potentially unlocking novel therapeutic vistas. This review endeavors to delineate the intricate mechanisms between the nervous system and BC, aiming to accentuate the implications and therapeutic strategies of this intersection for tumor evolution and the formulation of innovative therapeutic approaches.

SC-Unext: A Lightweight Image Segmentation Model with Cellular Mechanism for Breast Ultrasound Tumor Diagnosis

Automatic breast ultrasound image segmentation plays an important role in medical image processing. However, current methods for breast ultrasound segmentation suffer from high computational complexity and large model parameters, particularly when dealing with complex images. In this paper, we take the Unext network as a basis and utilize its encoder-decoder features. And taking inspiration from the mechanisms of cellular apoptosis and division, we design apoptosis and division algorithms to improve model performance. We propose a novel segmentation model which integrates the division and apoptosis algorithms and introduces spatial and channel convolution blocks into the model. Our proposed model not only improves the segmentation performance of breast ultrasound tumors, but also reduces the model parameters and computational resource consumption time. The model was evaluated on the breast ultrasound image dataset and our collected dataset. The experiments show that the SC-Unext model achieved Dice scores of 75.29% and accuracy of 97.09% on the BUSI dataset, and on the collected dataset, it reached Dice scores of 90.62% and accuracy of 98.37%. Meanwhile, we conducted a comparison of the model's inference speed on CPUs to verify its efficiency in resource-constrained environments. The results indicated that the SC-Unext model achieved an inference speed of 92.72 ms per instance on devices equipped only with CPUs. The model's number of parameters and computational resource consumption are 1.46M and 2.13 GFlops, respectively, which are lower compared to other network models. Due to its lightweight nature, the model holds significant value for various practical applications in the medical field.

Imaging-guided companion diagnostics in radiotherapy by monitoring APE1 activity with afterglow and MRI imaging

Companion diagnostics using biomarkers have gained prominence in guiding radiotherapy. However, biopsy-based techniques fail to account for real-time variations in target response and tumor heterogeneity. Herein, we design an activated afterglow/MRI probe as a companion diagnostics tool for dynamically assessing biomarker apurinic/apyrimidinic endonuclease 1(APE1) during radiotherapy in vivo. We employ ultrabright afterglow nanoparticles and ultrasmall FeMnOx nanoparticles as dual contrast agents, significantly broadening signal change range and enhancing the sensitivity of APE1 imaging (limit of detection: 0.0092 U/mL in afterglow imaging and 0.16 U/mL in MRI). We devise longitudinally and transversely subtraction-enhanced imaging (L&T-SEI) strategy to markedly enhance MRI contrast and signal-to-noise ratio between tumor and normal tissue of living female mice. The combined afterglow and MRI facilitate both anatomical and functional imaging of APE1 activity. This probe enables correlation of afterglow and MRI signals with APE1 expression, radiation dosage, intratumor ROS, and DNA damage, enabling early prediction of radiotherapy outcomes (as early as 3 h), significantly preceding tumor size reduction (6 days). By monitoring APE1 levels, this probe allows for early and sensitive detection of liver organ injury, outperforming histopathological analysis. Furthermore, MRI evaluates APE1 expression in radiation-induced abscopal effects provides insights into underlying mechanisms, and supports the development of treatment protocols.

Oxygen-Vacancy-Engineered W18 O49-x Nanobrush with a Suitable Band Structure for Highly Efficient Sonodynamic Therapy

With the rapid development of external minimally invasive or noninvasive therapeutic modalities, ultrasound-based sonodynamic therapy (SDT) is a new alternative for treating deep tumors. However, inadequate sonosensitizer efficiency and poor biosecurity limit clinical applications. In this study, we prepared an oxygen-vacancy-engineered W18 O49-x nanobrush with a band gap of 2.79 eV for highly efficient SDT using a simple solvothermal method. The suitable band structures of the W18 O49-x nanobrush endows it with the potential to simultaneously produce singlet oxygen (1 O2 ), superoxide anions (⋅O2 - ), and hydroxyl radicals (⋅OH) under ultrasound irradiation. Additionally, abundant oxygen vacancies that serve as further charge traps that inhibit electron-hole recombination are incidentally introduced through one-step thermal reduction. Collectively, the in vitro and in vivo results demonstrate that the oxygen-vacancy-engineered W18 O49-x nanobrush delivers highly efficient reactive oxygen species (ROS) for SDT in a very biosafe manner. Overall, this study provides a new avenue for discovering and designing inorganic nanosonosensitizers with enhanced therapeutic efficiencies for use in SDT.

Peptide-Conjugated MRI Probe Targeted to Netrin-1, a Novel Metastatic Breast Cancer Biomarker

Despite significant progress in cancer imaging and treatment over the years, early diagnosis and metastasis detection remain a challenge. Molecular magnetic resonance imaging (MRI), with its high resolution, can be well adapted to fulfill this need, requiring the design of contrast agents which target specific tumor biomarkers. Netrin-1 is an extracellular protein overexpressed in metastatic breast cancer and implicated in tumor progression and the appearance of metastasis. This study focuses on the design and preclinical evaluation of a novel Netrin-1-specific peptide-based MRI probe, GdDOTA-KKTHDAVR (Gd-K), to visualize metastatic breast cancer. The targeting peptide sequence was identified based on the X-ray structure of the complex between Netrin-1 and its transmembrane receptor DCC. Molecular docking simulations support the probe design. In vitro studies evidenced submicromolar affinity of Gd-K for Netrin-1 (KD = 0.29 μM) and good MRI efficacy (proton relaxivity, r1 = 4.75 mM-1 s-1 at 9.4 T, 37 °C). In vivo MRI studies in a murine model of triple-negative metastatic breast cancer revealed successful tumor visualization at earlier stages of tumor development (smaller tumor volume). Excellent signal enhancement, 120% at 2 min and 70% up to 35 min post injection, was achieved (0.2 mmol/kg injected dose), representing a reasonable imaging time window and a superior contrast enhancement in the tumor as compared to Dotarem injection.

New trends in non-pharmacological approaches for cardiovascular disease: Therapeutic ultrasound

Significant advances in application of therapeutic ultrasound have been reported in the past decades. Therapeutic ultrasound is an emerging non-invasive stimulation technique. This approach has shown high potential for treatment of various disease including cardiovascular disease. In this review, application principle and significance of the basic parameters of therapeutic ultrasound are summarized. The effects of therapeutic ultrasound in myocardial ischemia, heart failure, myocarditis, arrhythmias, and hypertension are explored, with key focus on the underlying mechanism. Further, the limitations and challenges of ultrasound therapy on clinical translation are evaluated to promote application of the novel strategy in cardiovascular diseases.

Emerging biomedical imaging-based companion diagnostics for precision medicine

The tumor heterogeneity, which leads to individual variations in tumor microenvironments, causes poor prognoses and limits therapeutic response. Emerging technology such as companion diagnostics (CDx) detects biomarkers and monitors therapeutic responses, allowing identification of patients who would benefit most from treatment. However, currently, most US Food and Drug Administration-approved CDx tests are designed to detect biomarkers in vitro and ex vivo, making it difficult to dynamically report variations of targets in vivo. Various medical imaging techniques offer dynamic measurement of tumor heterogeneity and treatment response, complementing CDx tests. Imaging-based companion diagnostics allow for patient stratification for targeted medicines and identification of patient populations benefiting from alternative therapeutic methods. This review summarizes recent developments in molecular imaging for predicting and assessing responses to cancer therapies, as well as the various biomarkers used in imaging-based CDx tests. We hope this review provides informative insights into imaging-based companion diagnostics and advances precision medicine.

Tumor-expressed factor VII is associated with survival and regulates tumor progression in breast cancer

Cancer enhances the risk of venous thromboembolism, but a hypercoagulant microenvironment also promotes cancer progression. Although anticoagulants have been suggested as a potential anticancer treatment, clinical studies on the effect of such modalities on cancer progression have not yet been successful for unknown reasons. In normal physiology, complex formation between the subendothelial-expressed tissue factor (TF) and the blood-borne liver-derived factor VII (FVII) results in induction of the extrinsic coagulation cascade and intracellular signaling via protease-activated receptors (PARs). In cancer, TF is overexpressed and linked to poor prognosis. Here, we report that increased levels of FVII are also observed in breast cancer specimens and are associated with tumor progression and metastasis to the liver. In breast cancer cell lines, tumor-expressed FVII drives changes reminiscent of epithelial-to-mesenchymal transition (EMT), tumor cell invasion, and expression of the prometastatic genes, SNAI2 and SOX9. In vivo, tumor-expressed FVII enhanced tumor growth and liver metastasis. Surprisingly, liver-derived FVII appeared to inhibit metastasis. Finally, tumor-expressed FVII-induced prometastatic gene expression independent of TF but required a functional endothelial protein C receptor, whereas recombinant activated FVII acting via the canonical TF:PAR2 pathway inhibited prometastatic gene expression. Here, we propose that tumor-expressed FVII and liver-derived FVII have opposing effects on EMT and metastasis.

The tumor-nerve circuit in breast cancer

It is well established that innervation is one of the updated hallmarks of cancer and that psychological stress promotes the initiation and progression of cancer. The breast tumor environment includes not only fibroblasts, adipocytes, endothelial cells, and lymphocytes but also neurons, which is increasingly discovered important in breast cancer progression. Peripheral nerves, especially sympathetic, parasympathetic, and sensory nerves, have been reported to play important but different roles in breast cancer. However, their roles in the breast cancer progression and treatment are still controversial. In addition, the brain is one of the favorite sites of breast cancer metastasis. In this review, we first summarize the innervation of breast cancer and its mechanism in regulating cancer growth and metastasis. Next, we summarize the neural-related molecular markers in breast cancer diagnosis and treatment. In addition, we review drugs and emerging technologies used to block the interactions between nerves and breast cancer. Finally, we discuss future research directions in this field. In conclusion, the further research in breast cancer and its interactions with innervated neurons or neurotransmitters is promising in the clinical management of breast cancer.

Netrin Family Genes as Prognostic Markers and Therapeutic Targets for Clear Cell Renal Cell Carcinoma: Netrin-4 Acts through the Wnt/β-Catenin Signaling Pathway

Clear cell renal cell carcinoma (ccRCC, or KIRC) is the most common type of kidney cancer, originating within the renal cortex. The current outcomes for early diagnosis and late treatment of ccRCC are unsatisfactory. Therefore, it is important to explore tumor biomarkers and therapeutic opportunities for ccRCC. In this study, we used bioinformatics methods to systematically evaluate the expression and prognostic value of Netrin family genes in ccRCC. Through our analysis, three potential biomarkers for ccRCC were identified, namely NTNG1, NTNG2, and NTN4. Moreover, we performed in vitro and in vivo experiments to explore the possible biological roles of NTN4 and found that NTN4 could regulate ccRCC development through Wnt/β-catenin signaling. We elucidate the molecular mechanism by which NTN4 modulates β-catenin expression and nuclear translocation to inhibit ccRCC progression, providing a new theoretical basis for developing therapeutic targets for ccRCC. Thus, we suggest that Netrin-related studies may offer new directions for the diagnosis, treatment, and prognosis of ccRCC patients.

From netrin-1-targeted SPECT/CT to internal radiotherapy for management of advanced solid tumors

Targeted radionuclide therapy is a revolutionary tool for the treatment of highly spread metastatic cancers. Most current approaches rely on the use of vectors to deliver radionuclides to tumor cells, targeting membrane-bound cancer-specific moieties. Here, we report the embryonic navigation cue netrin-1 as an unanticipated target for vectorized radiotherapy. While netrin-1, known to be re-expressed in tumoral cells to promote cancer progression, is usually characterized as a diffusible ligand, we demonstrate here that netrin-1 is actually poorly diffusible and bound to the extracellular matrix. A therapeutic anti-netrin-1 monoclonal antibody (NP137) has been preclinically developed and was tested in various clinical trials showing an excellent safety profile. In order to provide a companion test detecting netrin-1 in solid tumors and allowing the selection of therapy-eligible patients, we used the clinical-grade NP137 agent and developed an indium-111-NODAGA-NP137 single photon emission computed tomography (SPECT) contrast agent. NP137-¹¹¹ In provided specific detection of netrin-1-positive tumors with an excellent signal-to-noise ratio using SPECT/CT imaging in different mouse models. The high specificity and strong affinity of NP137 paved the way for the generation of lutetium-177-DOTA-NP137, a novel vectorized radiotherapy, which specifically accumulated in netrin-1-positive tumors. We demonstrate here, using tumor cell-engrafted mouse models and a genetically engineered mouse model, that a single systemic injection of NP137-¹⁷⁷ Lu provides important antitumor effects and prolonged mouse survival. Together, these data support the view that NP137-¹¹¹ In and NP137-¹⁷⁷ Lu may represent original and unexplored imaging and therapeutic tools against advanced solid cancers.

A Gambogic Acid-Loaded Delivery System Mediated by Ultrasound-Targeted Microbubble Destruction: A Promising Therapy Method for Malignant Cerebral Glioma

Background

Purpose

Methods

Results

Conclusion

Theranostic Microbubbles with Homogeneous Ligand Distribution for Higher Binding Efficacy

Phospholipid-coated targeted microbubbles are used for ultrasound molecular imaging and locally enhanced drug delivery, with the binding efficacy being an important trait. The use of organic solvent in microbubble production makes the difference between a heterogeneous or homogeneous ligand distribution. This study demonstrates the effect of ligand distribution on the binding efficacy of phospholipid-coated ανβ3-targeted microbubbles in vitro using a monolayer of human umbilical-vein endothelial cells and in vivo using chicken embryos. Microbubbles with a homogeneous ligand distribution had a higher binding efficacy than those with a heterogeneous ligand distribution both in vitro and in vivo. In vitro, 1.55× more microbubbles with a homogeneous ligand distribution bound under static conditions, while this was 1.49× more under flow with 1.25 dyn/cm2, 1.56× more under flow with 2.22 dyn/cm2, and 1.25× more in vivo. The in vitro dissociation rate of bound microbubbles with homogeneous ligand distribution was lower at low shear stresses (1–5 dyn/cm2). The internalized depth of bound microbubbles was influenced by microbubble size, not by ligand distribution. In conclusion, for optimal binding the use of organic solvent in targeted microbubble production is preferable over directly dispersing phospholipids in aqueous medium.

Ultrasound Molecular Imaging for the Guidance of Ultrasound-Triggered Release of Liposomal Doxorubicin and Its Treatment Monitoring in an Orthotopic Prostatic Tumor Model in Rat

Liposome encapsulation of drugs is an interesting approach in cancer therapy to specifically release the encapsulated drug at the desired treatment site. In addition to thermo-, pH-, light-, enzyme- or redox-responsive liposomes, which have had promising results in (pre-) clinical studies, ultrasound-triggered sonosensitive liposomes represent an exciting alternative to locally trigger the release from these cargos. Localized drug release requires precise tumor visualization to produce a targeted and ultrasound stimulus. We used ultrasound molecular imaging (USMI) with BR55, a vascular endothelial growth factor receptor 2 (VEGFR2)-targeted ultrasound contrast agent, to guide ultrasound-triggered release of sonosensitive liposomes encapsulating doxorubicin (L-DXR) in an orthotopic prostatic rodent tumor model. Forty-eight hours after L-DXR injection, local release of doxorubicin was triggered with a confocal ultrasound device with two focused transducers, 1.1-MHz center frequency, and peak positive and negative pressures of 20.5 and 13 MPa at focus. Tumor size decreased by 20% in 2 wk with L-DXR alone (n = 9) and by 70% after treatment with L-DXR and confocal ultrasound (n = 7) (p < 0.01). The effect of doxorubicin on perfusion/vascularity and VEGFR2 expression was evaluated by USMI and immunohistochemistry of CD31 and VEGFR2 and did not reveal differences in perfusion or VEGFR2 expression in the absence or after the triggered release of liposomes. USMI can provide precise guidance for ultrasound-triggered release of liposomal doxorubicin mediated by a confocal ultrasound device; moreover, the combination of B-mode imaging and USMI can help to follow the response of the tumor to the therapy.

Evaluation of Microwave Ablation in 4T1 Breast Tumor by a Novel VEFGR2 Targeted Ultrasound Contrast Agents

Objectives

A novel ultrasound contrast agent (UCA) VEGFR2-targeting iron-doped silica (SiO₂) hollow nanoparticles (VEGFR2-PEG-HSNs-Fe NPs) was prepared and applied in microwave ablation for breast cancer to investigate its value in the evaluation of effectiveness after tumor ablation.

Methods

VEGFR2-PEG-HSNs-Fe NPs were prepared by using nano-SiO₂, which was regarded as a substrate and etched by ferrous acetate, and then modified with anti-VEGFR2 antibody. Laser confocal microscope and flow cytometry were used to observe its main physicochemical properties, and biological safety was also investigated. After the xenograft tumor was treated with microwave ablation, the extent of perfusion defect was evaluated by ultrasound by injecting VEGFR2-PEG-HSNs-Fe NPs.

Results

The average particle size of VEGFR2-PEG-HSNs-Fe was 276.64 ± 30.31 nm, and the surface potential was −13.46 ± 2.83 mV. In vitro, the intensity of ultrasound signal increased with UCA concentration. Good biosafety was performed in in vivo and in vitro experiments. The enhanced ultrasound signal was detected in tumors after injection of VEGFR2-PEG-HSNs-Fe NPs, covering the whole tumor. The lesions, which were incompletely ablated, presented as contrast agent perfusion at the periphery of the tumor, and contrast enhanced ultrasound (CEUS) was performed again after complementary ablation. It was confirmed that all the lesions were completely ablated.

Conclusion

Nano-targeted UCAs VEGFR2-PEG-HSNs-Fe NPs had good biosafety and ability of specific imaging, which might be used as a contrast agent in CEUS to evaluate the efficacy of tumor ablation.

Phospholipid-coated targeted microbubbles for ultrasound molecular imaging and therapy

Phospholipid-coated microbubbles are ultrasound contrast agents that, when functionalized, adhere to specific biomarkers on cells. In this concise review, we highlight recent developments in strategies for targeting the microbubbles and their use for ultrasound molecular imaging (UMI) and therapy. Recently developed novel targeting strategies include magnetic functionalization, triple targeting, and the use of several new ligands. UMI is a powerful technique for studying disease progression, diagnostic imaging, and monitoring of therapeutic responses. Targeted microbubbles (tMBs) have been used for the treatment of cardiovascular diseases and cancer, with therapeutics either coadministered or loaded onto the tMBs. Regardless of which disease was treated, the use of tMBs always resulted in a better therapeutic outcome than non-tMBs when compared in vitro or in vivo.

Molecular ultrasound imaging of neutrophil membrane-derived biomimetic microbubbles for quantitative evaluation of hepatic ischemia-reperfusion injury

Rationale: Early diagnosis of hepatic ischemia-reperfusion injury (HIRI), the major cause of early allograft dysfunction or primary non-function, is critical in orthotopic liver transplantation. However, liver biopsy is still the primary method for HIRI evaluation in clinical practice despite its numerous complications and shortcomings such as hemorrhage and inaccuracy. Herein, we aimed to develop a non-invasive, highly accurate, and specific method for detecting HIRI. Methods: We developed a top-down and bottom-up strategy to fabricate neutrophil biomimetic microbubbles (MB_neu). Neutrophil membrane was mixed with liposomes at a defined mass ratio by sonication. The air in the vial was exchanged with perfluoropropane, and then the solution was mechanically vibrated to form MB_neu. Results: MB_neu retained the neutrophil proteins, preferentially targeted inflamed hepatic tissue in a rat model of HIRI, and demonstrated physicochemical properties typical of liposome-based MBs because of its artificial phospholipid content. With MB_neu we can quantitively evaluate the severity of HIRI, which is helpful for early diagnosis and the prediction of outcome. In addition, MB_neu was shown to be safe and showed no immunogenicity. Conclusion: We demonstrated molecular ultrasound imaging of HIRI with MB_neu. This new synthesis strategy may be applied to different clinical scenarios using other cell types in the future.

Ultrasound Molecular Imaging as a Potential Non-invasive Diagnosis to Detect the Margin of Hepatocarcinoma via CSF-1R Targeting

Though radiofrequency ablation (RFA) is considered to be an effective treatment for hepatocellular carcinoma (HCC), but more than 30% of patients may suffer insufficient RFA (IRFA), which can promote more aggressive of the residual tumor. One possible method to counter this is to accurately identify the margin of the HCC. Colony-stimulating factor 1 receptor (CSF-1R) has been found to be restrictively expressed by tumor associated macrophages (TAMs) and monocytes which more prefer to locate at the boundary of HCC. Using biotinylation method, we developed a CSF-1R-conjugated nanobubble CSF-1R (NB_CSF–1R) using a thin-film hydration method for margin detection of HCC. CSF-1R expression was higher in macrophages than in HCC cell lines. Furthermore, immunofluorescence showed that CSF-1R were largely located in the margin of xenograft tumor and IFRA models. In vitro, NB_CSF–1R was stable and provided a clear ultrasound image even after being stored for 6 months. In co-culture, NB_CSF–1R adhered to macrophages significantly better than HCC cells (p = 0.05). In in vivo contrast-enhanced ultrasound imaging, the washout half-time of the NB_CSF–1R was significantly greater than that of NB_CTRL and Sonovue^® (p = 0.05). The signal intensity of the tumor periphery was higher than the tumor center or non-tumor region after NB_CSF–1R injection. Taken together, NB_CSF–1R may potentially be used as a non-invasive diagnostic modality in the margin detection of HCC, thereby improving the efficiency of RFA. This platform may also serve as a complement method to detect residual HCC after RFA; and may also be used for targeted delivery of therapeutic drugs or genes.

Evaluation of ductal carcinoma in situ grade via triple-modal molecular imaging of B7-H3 expression

Ductal carcinoma in situ (DCIS) will account for 62,930 cases of breast cancer in 2019. DCIS is a pre-invasive lesion which may not progress to invasive carcinoma, yet surgery remains the mainstay treatment. Molecular imaging of a specific marker for DCIS grade for detection and active surveillance are critically needed to reduce potential overtreatment. First, breast cancer marker B7-H3 (CD276) expression was evaluated by immunohistochemical staining in 123 human specimens including benign epithelium (H-score 10.0 ± 8.2) and low (20.8 ± 17.7), intermediate (87.1 ± 69.5), and high (159.1 ± 87.6) grade DCIS, showing a positive association with DCIS nuclear grade (P < 0.001, AUC 0.96). Next, a murine DCIS model was combined with ultrasound molecular imaging of B7-H3 targeted microbubbles to differentiate normal glands from those harboring DCIS (n = 100, FVB/N-Tg(MMTVPyMT)634Mul, AUC 0.89). Finally, photoacoustic and fluorescence molecular imaging with an anti-B7-H3 antibody-indocyanine green conjugate were utilized for DCIS detection (n = 53). Molecular imaging of B7-H3 expression may allow for active surveillance of DCIS.