Current status of targeted microbubbles in diagnostic molecular imaging of pancreatic cancer

50-nm Gas-Filled Protein Nanostructures to Enable the Access of Lymphatic Cells by Ultrasound Technologies

Ultrasound imaging and ultrasound-mediated gene and drug delivery are rapidly advancing diagnostic and therapeutic methods; however, their use is often limited by the need for microbubbles, which cannot transverse many biological barriers due to their large size. Here, the authors introduce 50-nm gas-filled protein nanostructures derived from genetically engineered gas vesicles(GVs) that are referred to as 50 nmGVs. These diamond-shaped nanostructures have hydrodynamic diameters smaller than commercially available 50-nm gold nanoparticles and are, to the authors' knowledge, the smallest stable, free-floating bubbles made to date. 50 nmGVs can be produced in bacteria, purified through centrifugation, and remain stable for months. Interstitially injected 50 nmGVs can extravasate into lymphatic tissues and gain access to critical immune cell populations, and electron microscopy images of lymph node tissues reveal their subcellular location in antigen-presenting cells adjacent to lymphocytes. The authors anticipate that 50 nmGVs can substantially broaden the range of cells accessible to current ultrasound technologies and may generate applications beyond biomedicine as ultrasmall stable gas-filled nanomaterials.

Remote Loading: The Missing Piece for Achieving High Drug Payload and Rapid Release in Polymeric Microbubbles

The use of drug-loaded microbubbles for targeted drug delivery, particularly in cancer treatment, has been extensively studied in recent years. However, the loading capacity of microbubbles has been limited due to their surface area. Typically, drug molecules are loaded on or within the shell, or drug-loaded nanoparticles are coated on the surfaces of microbubbles. To address this significant limitation, we have introduced a novel approach. For the first time, we employed a transmembrane ammonium sulfate and pH gradient to load doxorubicin in a crystallized form in the core of polymeric microcapsules. Subsequently, we created remotely loaded microbubbles (RLMBs) through the sublimation of the liquid core of the microcapsules. Remotely loaded microcapsules exhibited an 18-fold increase in drug payload compared with physically loaded microcapsules. Furthermore, we investigated the drug release of RLMBs when exposed to an ultrasound field. After 120 s, an impressive 82.4 ± 5.5% of the loaded doxorubicin was released, demonstrating the remarkable capability of remotely loaded microbubbles for on-demand drug release. This study is the first to report such microbubbles that enable rapid drug release from the core. This innovative technique holds great promise in enhancing drug loading capacity and advancing targeted drug delivery.

A review study on early detection of pancreatic ductal adenocarcinoma using artificial intelligence assisted diagnostic methods

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive, chemo-refractory and recalcitrant cancer and increases the number of deaths. With just around 1 in 4 individuals having respectable tumours, PDAC is frequently discovered when it is in an advanced stage. Accordingly, ED of PDAC improves patient survival. Subsequently, this paper reviews the early detection of PDAC, initially, the work presented an overview of PDAC. Subsequently, it reviews the molecular biology of pancreatic cancer and the development of molecular biomarkers are represented. This article illustrates the importance of identifying PDCA, the Immune Microenvironment of Pancreatic Cancer. Consequently, in this review, traditional and non-traditional imaging techniques are elucidated, traditional and non-traditional methods like endoscopic ultrasound, Multidetector CT, CT texture analysis, PET-CT, magnetic resonance imaging, diffusion-weighted imaging, secondary signs of pancreatic cancer, and molecular imaging. The use of artificial intelligence in pancreatic cancer, novel MRI techniques, and the future directions of AI for PDAC detection and prognosis is then described. Additionally, the research problem definition and motivation, current trends and developments, state of art of survey, and objective of the research are demonstrated in the review. Consequently, this review concluded that Artificial Intelligence Assisted Diagnostic Methods with MRI images can be proposed in future to improve the specificity and the sensitivity of the work, and to classify malignant PDAC with greater accuracy.

Radiation combined with ultrasound and microbubbles: A potential novel strategy for cancer treatment

Cancer is one of the leading causes of death worldwide. Several emerging technologies are helping to battle cancer. Cancer therapies have been effective at killing cancer cells, but a large portion of patients still die to this disease every year. As such, more aggressive treatments of primary cancers are employed and have been shown to be capable of saving a greater number of lives. Recent research advances the field of cancer therapy by employing the use of physical methods to alter tumor biology. It uses microbubbles to enhance radiation effect by damaging tumor vasculature followed by tumor cell death. The technique can specifically target tumor volumes by conforming ultrasound fields capable of microbubbles stimulation and localizing it to avoid vascular damage in surrounding tissues. Thus, this new application of ultrasound-stimulated microbubbles (USMB) can be utilized as a novel approach to cancer therapy by inducing vascular disruption resulting in tumor cell death. Using USMB alongside radiation has showed to augment the anti-vascular effect of radiation, resulting in enhanced tumor response. Recent work with nanobubbles has shown vascular permeation into intracellular space, extending the use of this new treatment method to potentially further improve the therapeutic effect of the ultrasound-based therapy. The significant enhancement of localized tumor cell kill means that radiation-based treatments can be made more potent with lower doses of radiation. This technique can manifest a greater impact on radiation oncology practice by increasing treatment effectiveness significantly while reducing normal tissue toxicity. This review article summarizes the past and recent advances in USMB enhancement of radiation treatments. The review mainly focuses on preclinical findings but also highlights some clinical findings that use USMB as a therapeutic modality in cancer therapy.

Noninvasive quantification of granzyme B in cardiac allograft rejection using targeted ultrasound imaging

Objective

Endomyocardial biopsy is the gold standard method for the diagnosis of cardiac allograft rejection. However, it causes damage to the heart. In this study, we developed a noninvasive method for quantification of granzyme B (GzB) in vivo by targeted ultrasound imaging, which detects and provides quantitative information for specific molecules, for acute rejection assessment in a murine cardiac transplantation model.

Methods

Microbubbles bearing anti-GzB antibodies (MB_Gzb) or isotype antibodies (MBcon) were prepared. Hearts were transplanted from C57BL/6J (allogeneic) or C3H (syngeneic) donors to C3H recipients. Target ultrasound imaging was performed on Days 2 and 5 post-transplantations. A pathologic assessment was performed. The expression of granzyme B and IL-6 in the heart was detected by Western blotting.

Results

After MB injection, we observed and collected data at 3 and 6 min before and after the flash pulse. Quantitative analysis revealed that the reduction in peak intensity was significantly higher in the allogeneic MB_Gzb group than in the allogeneic MB_con group and the isogeneic MB_con group at PODs 2 and 5. In the allogeneic groups, granzyme B and IL-6 expression levels were higher than those in the isogeneic group. In addition, more CD8 T cells and neutrophils were observed in the allogeneic groups.

Conclusion

Ultrasound molecular imaging of granzyme B can be used as a noninvasive method for acute rejection detection after cardiac transplantation.

Immunotheranostic microbubbles (iMBs) - a modular platform for dendritic cell vaccine delivery applied to breast cancer immunotherapy

BACKGROUND

Therapeutic strategies engaging the immune system against malignant cells have revolutionized the field of oncology. Proficiency of dendritic cells (DCs) for antigen presentation and immune response has spurred interest on DC-based vaccines for anti-cancer therapy. However, despite favorable safety profiles in patients, current DC-vaccines have not yet presented significant outcome due to technical barriers in active DC delivery, tumor progression, and immune dysfunction. To maximize the therapeutic response, we present here a unique cell-free DC-based vaccine capable of lymphoid organ targeting and eliciting T-cell-mediated anti-tumor effect.

METHODS

We developed this novel immunotheranostic platform using plasma membranes derived from activated DCs incorporated into ultrasound contrast microbubbles (MBs), thereby offering real-time visualization of MBs' trafficking and homing in vivo. Human PBMC-derived DCs were cultured ex vivo for controlled maturation and activation using cell membrane antigens from breast cancer cells. Following DC membrane isolation, immunotheranostic microbubbles, called DC-iMBs, were formed for triple negative breast cancer treatment in a mouse model harboring a human reconstituted immune system.

RESULTS

Our results demonstrated that DC-iMBs can accumulate in lymphoid organs and induce anti-tumor immune response, which significantly reduced tumor growth via apoptosis while increasing survival length of the treated animals. The phenotypic changes in immune cell populations upon DC-iMBs delivery further confirmed the T-cell-mediated anti-tumor effect.

CONCLUSION

These early findings strongly support the potential of DC-iMBs as a novel immunotherapeutic cell-free vaccine for anti-cancer therapy.

Next-Generation Colloidal Materials for Ultrasound Imaging Applications

Ultrasound has important applications, predominantly in the field of diagnostic imaging. Presently, colloidal systems such as microbubbles, phase-change emulsion droplets and particle systems with acoustic properties and multiresponsiveness are being developed to address typical issues faced when using commercial ultrasound contrast agents, and to extend the utility of such systems to targeted drug delivery and multimodal imaging. Current technologies and increasing research data on the chemistry, physics and materials science of new colloidal systems are also leading to the development of more complex, novel and application-specific colloidal assemblies with ultrasound contrast enhancement and other properties, which could be beneficial for multiple biomedical applications, especially imaging-guided treatments. In this article, we review recent developments in new colloids with applications that use ultrasound contrast enhancement. This work also highlights the emergence of colloidal materials fabricated from or modified with biologically derived and bio-inspired materials, particularly in the form of biopolymers and biomembranes. Challenges, limitations, potential developments and future directions of these next-generation colloidal systems are also presented and discussed.

Antibody-Incorporated Nanomedicines for Cancer Therapy

Antibody-based cancer therapy, one of the most significant therapeutic strategies, has achieved considerable success and progress over the past decades. Nevertheless, obstacles including limited tumor penetration, short circulation half-lives, undesired immunogenicity, and off-target side effects remain to be overcome for the antibody-based cancer treatment. Owing to the rapid development of nanotechnology, antibody-containing nanomedicines that have been extensively explored to overcome these obstacles have already demonstrated enhanced anticancer efficacy and clinical translation potential. This review intends to offer an overview of the advancements of antibody-incorporated nanoparticulate systems in cancer treatment, together with the nontrivial challenges faced by these next-generation nanomedicines. Diverse strategies of antibody immobilization, formats of antibodies, types of cancer-associated antigens, and anticancer mechanisms of antibody-containing nanomedicines are provided and discussed in this review, with an emphasis on the latest applications. The current limitations and future research directions on antibody-containing nanomedicines are also discussed from different perspectives to provide new insights into the construction of anticancer nanomedicines.

Nanodiscs: a versatile nanocarrier platform for cancer diagnosis and treatment

Cancer therapy is a significant challenge due to insufficient drug delivery to the cancer cells and non-selective killing of healthy cells by most chemotherapy agents. Nano-formulations have shown great promise for targeted drug delivery with improved efficiency. The shape and size of nanocarriers significantly affect their transport inside the body and internalization into the cancer cells. Non-spherical nanoparticles have shown prolonged blood circulation half-lives and higher cellular internalization frequency than spherical ones. Nanodiscs are desirable nano-formulations that demonstrate enhanced anisotropic character and versatile functionalization potential. Here, we review the recent development of theranostic nanodiscs for cancer mitigation ranging from traditional lipid nanodiscs encased by membrane scaffold proteins to newer nanodiscs where either the membrane scaffold proteins or the lipid bilayers themselves are replaced with their synthetic analogues. We first discuss early cancer detection enabled by nanodiscs. We then explain different strategies that have been explored to carry a wide range of payloads for chemotherapy, cancer gene therapy, and cancer vaccines. Finally, we discuss recent progress on organic-inorganic hybrid nanodiscs and polymer nanodiscs that have the potential to overcome the inherent instability problem of lipid nanodiscs.

Nanocarriers for pancreatic cancer imaging, treatments, and immunotherapies

Pancreatic tumors are highly desmoplastic and immunosuppressive. Delivery and distribution of drugs within pancreatic tumors are compromised due to intrinsic physical and biochemical stresses that lead to increased interstitial fluid pressure, vascular compression, and hypoxia. Immunotherapy-based approaches, including therapeutic vaccines, immune checkpoint inhibition, CAR-T cell therapy, and adoptive T cell therapies, are challenged by an immunosuppressive tumor microenvironment. Together, extensive fibrosis and immunosuppression present major challenges to developing treatments for pancreatic cancer. In this context, nanoparticles have been extensively studied as delivery platforms and adjuvants for cancer and other disease therapies. Recent advances in nanotechnology have led to the development of multiple nanocarrier-based formulations that not only improve drug delivery but also enhance immunotherapy-based approaches for pancreatic cancer. This review discusses and critically analyzes the novel nanoscale strategies that have been used for drug delivery and immunomodulation to improve treatment efficacy, including newly emerging immunotherapy-based approaches. This review also presents important perspectives on future research directions that will guide the rational design of novel and robust nanoscale platforms to treat pancreatic tumors, particularly with respect to targeted therapies and immunotherapies. These insights will inform the next generation of clinical treatments to help patients manage this debilitating disease and enhance survival rates.

Expression and purification of a native Thy1-single-chain variable fragment for use in molecular imaging

Molecular imaging using singlechain variable fragments (scFv) of antibodies targeting cancer specific antigens have been considered a non-immunogenic approach for early diagnosis in the clinic. Usually, production of proteins is performed within Escherichia coli. Recombinant proteins are either expressed in E. coli cytoplasm as insoluble inclusion bodies, that often need cumbersome denaturation and refolding processes, or secreted toward the periplasm as soluble proteins that highly reduce the overall yield. However, production of active scFvs in their native form, without any heterologous fusion, is required for clinical applications. In this study, we expressed an anti-thymocyte differentiation antigen-scFv (Thy1-scFv) as a fusion protein with a N-terminal sequence including 3 × hexa-histidines, as purification tags, together with a Trx-tag and a S-tag for enhanced-solubility. Our strategy allowed to recover ~ 35% of Thy1-scFv in the soluble cytoplasmic fraction. An enterokinase cleavage site in between Thy1-scFv and the upstream tags was used to regenerate the protein with 97.7 ± 2.3% purity without any tags. Thy1-scFv showed functionality towards its target on flow cytometry assays. Finally, in vivo molecular imaging using Thy1-scFv conjugated to an ultrasound contrast agent (MBThy1-scFv) demonstrated signal enhancement on a transgenic pancreatic ductal adenocarcinoma (PDAC) mouse model (3.1 ± 1.2 a.u.) compared to non-targeted control (0.4 ± 0.4 a.u.) suggesting potential for PDAC early diagnosis. Overall, our strategy facilitates the expression and purification of Thy1-scFv while introducing its ability for diagnostic molecular imaging of pancreatic cancer. The presented methodology could be expanded to other important eukaryotic proteins for various applications, including but not limited to molecular imaging.

[Effect of DR5-mediated docetaxel-loaded lipid microbubble combined with ultrasoundtargeted microbubble destruction on HepG2 cell proliferation and apoptosis]

OBJECTIVE

To investigate the effect of DR5-mediated docetaxel-targeted lipid microbubbles (MBs) combined with ultrasound-targeted microbubble destruction on apoptosis and expressions of Bcl-2, nuclear factor-κB(NF-κB), caspase-8, and DR5 in human HepG2 cells.

METHODS

HepG2 cells were treated with docetaxel at its 50% inhibitory concentration (IC50) of 5 nmol/L, docetaxel combined with ultrasound, blank MBs, blank MBs combined with ultrasound (0.5 W/cm2 for 45 s), drugloaded lipid MBs (DLLM), DLLM combined with ultrasound, DR5-mediated DLLM (DR5-DLLM), or DR5-DLLM combined with ultrasound.After the treatments, the cells were further cultured for 24 h, and CCK-8 assay, TUNEL staining and flow cytometry were used to assess cell proliferation, apoptosis, and cell cycle changes; the changes in mRNA and protein expression levels of Bcl-2, NF-κB, caspase-8, and DR5 were detected with RT-qPCR and Western blotting.

RESULTS

Among all the treatments, DR5-DLLM combined with ultrasound produced the strongest effects to inhibit the proliferation (P < 0.001), promote apoptosis (P < 0.001), and cause G2/M cell cycle arrest (P < 0.001) in HepG2 cells.The combined treatment with DR5-DLLM and ultrasound also significantly downregulated Bcl-2 and NF-κB (P < 0.001) and upregulated DR5 and caspase-8 expressions (P < 0.001) at both the mRNA and protein levels.

CONCLUSION

DR5-DLLM combined with ultrasound-targeted microbubble destruction can induce G2/M cell cycle arrest, proliferation inhibition and apoptosis in HepG2 cells by downregulating Bcl-2 and NF-κB and upregulating DR5 and caspase-8 expressions, indicating its value as a novel ultrasoundtargeted therapy for liver cancer.

Emerging roles of a pivotal lncRNA SBF2-AS1 in cancers

Long non-coding RNAs refer to transcripts over 200 nt in length that lack the ability to encode proteins, which occupy the majority of the genome and play a crucial role in the occurrence and development of human diseases, especially cancers. SBF2-AS1, a newly identified long non-coding RNA, has been verified to be highly expressed in diversiform cancers, and is involved in processes promoting tumorigenesis, tumor progression and tumor metastasis. Moreover, upregulation of SBF2-AS1 expression was significantly related to disadvantageous clinicopathologic characteristics and indicated poor prognosis. In this review, we comprehensively summarize the up-to-date knowledge of the detailed mechanisms and underlying functions of SBF2-AS1 in diverse cancer types, highlighting the potential of SBF2-AS1 as a diagnostic and prognostic biomarker and even a therapeutic target.