NIR-responsive nanoplatform for pre/intraoperative image-guided carcinoma surgery and photothermal ablation of residual tumor tissue

Recent progress on near-infrared fluorescence heptamethine cyanine dye-based molecules and nanoparticles for tumor imaging and treatment

Recenly, near-infrared fluorescence heptamethine cyanine dyes have shown satisfactory values in bioengineering, biology, and pharmacy especially in cancer diagnosis and treatment, owing to their excellent fluorescence property and biocompatibility. In order to achieve broad application prospects, diverse structures, and chemical properties of heptamethine cyanine dyes have been designed to develop novel functional molecules and nanoparticles over the past decade. For fluorescence and photoacoustic tumor imaging properties, heptamethine cyanine dyes are equipped with good photothermal performance and reactive oxygen species production properties under near-infrared light irradiation, thus holding great promise in photodynamic and/or photothermal cancer therapies. This review offers a comprehensive scope of the structures, comparisons, and applications of heptamethine cyanine dyes-based molecules as well as nanoparticles in tumor treatment and imaging in current years. Therefore, this review may drive the development and innovation of heptamethine cyanine dyes, significantly offering opportunities for improving tumor imaging and treatment in a precise noninvasive manner. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

An Acid Response IR780-Based Targeted Nanoparticle for Intraoperative Near-Infrared Fluorescence Imaging of Ovarian Cancer

INTRODUCTION

Complete resection of all visible disease (R0 resection) is critical for the treatment of ovarian cancer patients, and accurate real-time guidance provided by intraoperative near-infrared (NIR) fluorescence images is beneficial for achieving complete resection of all visible disease.

METHODS

Based on the optical properties of IR780 and the characteristics of the acidic tumor microenvironment, we develop a new smart nanoparticle (eg, FA-IR780&PFOB-SNPs) by using the pH response nano framework (FA-PEG-PLGA-PEOz) and adjusting the amount of IR780. The FA-IR780&PFOB-SNPs was characterized for morphology, microstructure, particle size, pH-response, drug-loading efficiency and biological safety. The ultraclear fluorescence Navigation Endoscopy System was applied to evaluate the tumor recognition of FA-IR780&PFOB-SNPs in vivo.

RESULTS

The structure of FA-IR780&PFOB-SNPs was stable in a neutral environment, and the near-infrared (NIR) fluorescence was turned off, while the structure of FA-IR780&PFOB-SNPs was degraded in the acidic tumour microenvironment, and the NIR fluorescence was turned on. Through the ovarian subcutaneous xenograft tumour and ovarian intraperitoneal xenograft tumour models, it was confirmed that FA-IR780&PFOB-SNPs could clearly display the boundaries of abdominal micron-sized tumours through near-infrared fluorescence imaging, with a TBR greater than 5.

CONCLUSION

The FA-IR780&PFOB-SNPs have the potential to provide to ovarian cancer intraoperative near infrared fluorescence navigation during precision tumour resection to achieve R0 and improve the prognosis of ovarian cancer patients.

Phase-shift Perfluoropentane Nanoemulsions Enhance Pulsed High-intensity Focused Ultrasound Ablation in an Isolated Perfused Liver System and Their Potential Value for Cancer Therapy

PURPOSE

To investigate whether phase-shift perfluoropetane (PFP) nanoemulsions can enhance pulsed high-intensity focused ultrasound (HIFU) ablation.

METHODS

PFP was encapsulated by poly(lactic-co-glycolic acid) (PLGA) to form a nanometer-sized droplet (PLGA-PFP), which was added to an isolated perfused liver system. Meanwhile, phosphate-buffered saline (PBS) was used as a control. The perfused liver was exposed to HIFU (150 W, t = 3/5/10 s) at various duty cycles (DCs). The ultrasound images, cavitation emissions, and temperature were recorded. Rabbits with subcutaneous VX2 tumors were exposed to HIFU (150 W) at various DCs with or without PLGA-PFP. After ablation, necrosis volume and energy efficiency factor were calculated. Pathologic characteristics were observed.

RESULTS

Compared to the PBS control, PLGA-PFP nanoemulsions markedly enhanced HIFU-induced necrosis volume in both perfused livers and subcutaneous VX2 tumor-bearing rabbits (P <.05). Inertial cavitation was much stronger in the pulsed-HIFU exposure at 10% than that in the continuous-wave HIFU exposure (P <.01). Peak temperature at 100% DC was significantly higher than that at 10% (P <.05). Compared to 100% DC HIFU exposure, the mean necrosis volume induced by 10 s exposure at 50% DC was significantly larger (P <.005) but lower at 10% DC in the isolated perfused livers (P <.05). In addition, the mean necrosis volume in subcutaneous VX2 tumor-bearing rabbits was significantly increased after HIFU exposure at 10% DC when compared to those at 100% DC (P <.05). Histopathologic analysis showed liquefaction necrosis in pulsed HIFU.

CONCLUSION

PLGA-PFP nanoemulsions can enhance HIFU ablation in the isolated perfused livers and promote tumor ablation in the subcutaneous xenograft rabbit model. Appropriate pulsed HIFU exposure may increase the necrosis volume and reduce total ultrasound energy required for HIFU ablation.

Mitochondria-targeted nanoplatforms for enhanced photodynamic therapy against hypoxia tumor

Background

Photodynamic therapy (PDT) is a promising therapeutic modality that can convert oxygen into cytotoxic reactive oxygen species (ROS) via photosensitizers to halt tumor growth. However, hypoxia and the unsatisfactory accumulation of photosensitizers in tumors severely diminish the therapeutic effect of PDT. In this study, a multistage nanoplatform is demonstrated to overcome these limitations by encapsulating photosensitizer IR780 and oxygen regulator 3-bromopyruvate (3BP) in poly (lactic-co-glycolic acid) (PLGA) nanocarriers.

Results

The as-synthesized nanoplatforms penetrated deeply into the interior region of tumors and preferentially remained in mitochondria due to the intrinsic characteristics of IR780. Meanwhile, 3BP could efficiently suppress oxygen consumption of tumor cells by inhibiting mitochondrial respiratory chain to further improve the generation of ROS. Furthermore, 3BP could abolish the excessive glycolytic capacity of tumor cells and lead to the collapse of ATP production, rendering tumor cells more susceptible to PDT. Successful tumor inhibition in animal models confirmed the therapeutic precision and efficiency. In addition, these nanoplatforms could act as fluorescence (FL) and photoacoustic (PA) imaging contrast agents, effectuating imaging-guided cancer treatment.

Conclusions

This study provides an ideal strategy for cancer therapy by concurrent oxygen consumption reduction, oxygen-augmented PDT, energy supply reduction, mitochondria-targeted/deep-penetrated nanoplatforms and PA/FL dual-modal imaging guidance/monitoring. It is expected that such strategy will provide a promising alternative to maximize the performance of PDT in preclinical/clinical cancer treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01196-6.

Photothermal Therapy as Adjuvant to Surgery in an Orthotopic Mouse Model of Human Fibrosarcoma

Simple Summary

Combining tumor surgery with other types of treatment can be useful when dealing with aggressive tumors or tumors in difficult locations. Photothermal therapy (PTT) is a technique based on the use of light-absorbing nanoparticles that accumulate in the tumor. When tumors are irradiated with a laser, these nanoparticles transform the laser light into heat, causing very localized tumor death and sparing healthy neighboring tissues. In this study, we evaluated a treatment strategy consisting of surgery followed by PTT in a highly aggressive mouse model of fibrosarcoma. Using magnetic resonance imaging, we observed a slowdown in tumor growth accompanied by improved survival in mice that underwent PTT and surgery compared to animals that only had surgery. This shows the potential of combining PTT with surgery, an approach that can potentially be valuable to multiple types of cancer.

Abstract

Surgery is still the first-line treatment for multiple solid cancers. However, recurrence is a common issue, especially when dealing with aggressive tumors or tumors that are difficult to completely remove due to their location. Getting clear surgical margins can be challenging, but treatment strategies combining surgery with other anti-cancer therapies can potentially improve the outcome. Photothermal therapy (PTT) is a technique that relies on photoabsorbing agents, such as gold nanoparticles, to transform light into local hyperthermia. This technique can be used to ablate tumor tissue where the photoabsorbing agent accumulates, sparing healthy surrounding tissue. In this study, we examined the potential of gold nanoparticle-based PTT as an adjuvant treatment to surgery in a mouse model of human fibrosarcoma. For this we performed subtotal tumor resection to mimic a clinical situation where total tumor removal is not achieved, and subsequent PTT was applied on the surgical field. Our results showed that animals undergoing adjuvant PTT after surgery presented sustained delayed tumor growth and improved survival when compared to animals that only underwent surgery. We believe that these findings show the potential of PTT as an adjuvant method to traditional tumor surgery and could pave way to more personalized treatment options.

Improving Image-Guided Surgical and Immunological Tumor Treatment Efficacy by Photothermal and Photodynamic Therapies Based on a Multifunctional NIR AIEgen

Multimodal therapy is attracting increasing attention to improve tumor treatment efficacy, but generally requires various complicated ingredients combined within one theranostic system to achieve multiple functions. Herein, a multifunctional theranostic nanoplatform based on a single aggregation-induced-emission luminogen (AIEgen), DDTB, is designed to integrate near-infrared (NIR) fluorescence, photothermal, photodynamic, and immunological effects. Intravenously injected AIEgen-based nanoparticles can efficiently accumulate in tumors with NIR fluorescence to provide preoperative diagnosis. Most of the tumors are excised under intraoperative fluorescence navigation, whereafter, some microscopic residual tumors are completely ablated by photodynamic and photothermal therapies for maximally killing the tumor cells and tissues. Up to 90% of the survival rate can be achieved by this synergistic image-guided surgery and photodynamic and photothermal therapies. Importantly, the nanoparticles-mediated photothermal/photodynamic therapy plus programmed death-ligand 1 antibody significantly induce tumor elimination by enhancing the effect of immunotherapy. This theranostic strategy on the basis of a single AIEgen significantly improves the survival of cancer mice with maximized therapeutic outcomes, and holds great promise for clinical cancer treatment.

IR780-based nanomaterials for cancer imaging and therapy

IR780, a small molecule with a strong optical property and excellent photoconversion efficiency following near infrared (NIR) irradiation, has attracted increasing attention in the field of cancer treatment and imaging. This review is focused on different IR780-based nanoplatforms and the application of IR780-based nanomaterials for cancer bioimaging and therapy. Thus, this review summarizes the overall aspects of IR780-based nanomaterials that positively impact cancer biomedical applications.

Dual mitigation of immunosuppression combined with photothermal inhibition for highly effective primary tumor and metastases therapy

T-cell based immune response can attack cancer cells formidably when certain immune checkpoint (e.g., PD-1/PD-L1) is blocked. Unfortunately, PD-1/PD-L1 blockade only provoke limited immune response because the differentiation of tumor-reactive T lymphocytes is often suppressed by TGF-β pathway. Namely, the combating cancer weapon is weakened. In this study, other than employing photothermal therapy (PTT) to eliminate the primary tumor, we also aimed to expose in situ tumor-associated antigens and exert immune response for metastases inhibition. This enhanced immunotherapeutic strategy is achieved by IR780/SB-505124 based nanoliposomes (Nano-IR-SB@Lip). Upon administration, TGF-β pathway is inhibited by SB to drive effector T cells into a responsive state and reduce the infiltration of Treg cells, eventually greatly enhancing the weapon against cancer. In the meantime, the immunosuppressive "protection" of tumor cells is also neutralized by blocking PD-1/PD-L1 immune checkpoint. By virtue of inherent characteristics of IR780, Nano-IR-SB@Lip can selectively accumulate, penetrate deeply in tumor tissues, and preferentially retain in mitochondria. The above features are of critical importance to tumor therapy. Thus, highly effective cancer immunotherapy is implemented via selective accumulation/deep penetration of Nano-IR-SB@Lip in tumor, achieving PTT induced immunogenic cell death and dual mitigation of immunosuppression strategy (TGF-β inhibition/PD-1/PD-L1 blockade), which is a promising therapeutic modality for cancer.

In vivo Multi-scale Photoacoustic Imaging Guided Photothermal Therapy of Cervical Cancer based on Customized Laser System and Targeted Nanoparticles

BACKGROUND

Effective treatment strategy for cervical carcinoma is subject to the limitation of its anatomical location and histological characteristics. Comprehensive imaging before cervical carcinoma treatment is of great significance for the patients. Current imaging methods cannot meet the requirements of high resolution, deep imaging depth and non-invasive imaging at the same time. Fortunately, Photoacoustic imaging (PAI) is a novel imaging method that combines rich optical contrast, high ultrasonic spatial resolution, and deep penetration depth in a single modality. Moreover, PAI-guided photothermal therapy (PTT) by aid of targeting nanoparticles is an emerging and effective cancer treatment in recent years.

METHODS

Here, strong near-infrared region (NIR) absorption-conjugated polymer PIIGDTS (PD) nanoparticles with folic acid (FA) modification (namely, PD-FA) that targeted at Hela cell were specifically designed as cervical tumor imaging contrast agents and photothermal agents.

RESULTS

The obtained PD-FA nanoparticles exhibited admirable photoacoustic contrast-enhancing ability and desirable PTT behavior with the photothermal conversion efficiency as high as 62.6% in vitro. Furthermore, the PAI performance and PTT efficiency were tested in HeLa tumor-bearing nude mice after injection of PD-FA nanoparticles. In vivo multi-scale, PAI provided B-san and 3D dimension imaging for intuitive and comprehensive information of Hela tumor. Moreover, the Hela tumor can be completely eliminated within 18 days after PTT, with no toxicity and side effects.

CONCLUSION

In summary, PD-FA injection combined with PAI and PTT systems provides a novel powerful tool for early diagnosis and precise treatment of cervical cancer.

Application and Importance of Theranostics in the Diagnosis and Treatment of Cancer

The number of cancer cases worldwide in terms of morbidity and mortality is a serious concern, despite the presence of therapeutic interventions and supportive care. Limitations in the current available diagnosis methods and treatments methods may contribute to the increase in cancer mortality. Theranostics, is a novel approach that has opened avenues for the simultaneous precise diagnosis and treatment for cancer patients. Although still in the early development stage, theranostic agents such as quantum dots, radioisotopes, liposomes and plasmonic nanobubbles can be bound to anticancer drugs, cancer cell markers and imaging agents, with the support of available imaging techniques, provide the potential to facilitate diagnosis, treatment and management of cancer patients. Herein, we discuss the potential benefits of several theranostic tools for the management of cancer. Specifically, quantum dots, radio-labelled isotopes, liposomes and plasmonic nanobubbles coupled with targeting agents and/or anticancer molecules and imaging agents as theranostic agents are deliberated upon in this review. Overall, the use of theranostic agents shows promise in cancer management. Nevertheless, intensive research is required to realize these expectations.

Novel biomimetic dual-mode nanodroplets as ultrasound contrast agents with potential ability of precise detection and photothermal ablation of tumors

PURPOSE

Molecule-targeted ultrasound imaging has attracted extensive attention for precise diagnosis and targeted therapy of tumors. The aim of this research is to prepare novel biomimetic dual-mode nanoscale ultrasound contrast agents (UCAs), which can not only evade the immune clearance of reticuloendothelial system, but also have the potential ability of precise detection and photothermal ablation of tumors.

METHODS

In this study, for the first time, the novel biomimetic UCAs were prepared by encapsulating liquid perfluorohexanes with red blood cell membranes carrying IR-780 iodide and named IR780-RBCM@NDs. The characteristics of that were verified through the particle size analyzer, scanning electron microscopy, transmission electron microscopy and laser scanning confocal microscopy. The stability of IR780-RBCM@NDs at 37 °C was explored. The abilities of immune escape, dual-mode imaging and photothermal effect for IR780-RBCM@NDs were verified via in vitro experiments.

RESULTS

The novel prepared nanodroplets have good characteristics such as mean diameter, zeta potential, and relatively stability. Importantly, the integrin-associated protein expressed on the surface of RBCMs was detected on IR780-RBCM@NDs. Then, compared with control groups, IR780-RBCM@NDs performed excellent immune escape function away from macrophages in vitro. Furthermore, the IR-780 iodide was observed on the new nanodroplets and that was able to perform the dual-mode imaging with near-infrared fluorescence imaging and contrast-enhanced ultrasound imaging after the phase change. Finally, the effective photothermal ablation ability of IR780-RBCM@NDs was verified in tumor cells.

CONCLUSION

The newly prepared biomimetic IR780-RBCM@NDs provided novel ideas for evading immune clearance, performing precise diagnosis and photothermal ablation of tumor cells.

Nanoparticle-Based Platform for Activatable Fluorescence Imaging and Photothermal Ablation of Endometriosis

Endometriosis is a painful disorder where endometrium-like tissue forms lesions outside of the uterine cavity. Intraoperative identification and removal of these lesions are difficult. This study presents a nanoplatform that concurrently delineates and ablates endometriosis tissues using real-time near-infrared (NIR) fluorescence and photothermal therapy (PTT). The nanoplatform consists of a dye, silicon naphthalocyanine (SiNc), capable of both NIR fluorescence imaging and PTT, and a polymeric nanoparticle as a SiNc carrier to endometriosis tissue following systemic administration. To achieve high contrast during fluorescence imaging of endometriotic lesions, nanoparticles are constructed to be non-fluorescent prior to internalization by endometriosis cells. In vitro studies confirm that these nanoparticles activate the fluorescence signal following internalization in macaque endometrial stromal cells and ablate them by increasing cellular temperature to 53 ^° C upon interaction with NIR light. To demonstrate in vivo efficiency of the nanoparticles, biopsies of endometrium and endometriosis from rhesus macaques are transplanted into immunodeficient mice. Imaging with the intraoperative Fluobeam 800 system reveals that 24 h following intravenous injection, nanoparticles efficiently accumulate in, and demarcate, endometriotic grafts with fluorescence. Finally, the nanoparticles increase the temperature of endometriotic grafts up to 47 °C upon exposure to NIR light, completely eradicating them after a single treatment.

Prototypic Heptamethine Cyanine Incorporating Nanomaterials for Cancer Phototheragnostic

Developing technologies that allow the simultaneous diagnosis and treatment of cancer (theragnostic) has been the quest of numerous interdisciplinary research teams. In this context, nanomaterials incorporating prototypic near infrared (NIR)-light responsive heptamethine cyanines have been showing very promising results for cancer theragnostic. The precisely engineered features of these nanomaterials endow them with the ability to achieve a high tumor accumulation, enabling a tumor's visualization by NIR fluorescence and photoacoustic imaging modalities. Upon interaction with NIR light, the tumor-homed heptamethine cyanine-incorporating nanomaterials can also produce a photothermal/photodynamic effect with a high spatio-temporal resolution and minimal side effects, leading to an improved therapeutic outcome. This progress report analyses the application of nanomaterials incorporating prototypic NIR-light responsive heptamethine cyanines (IR775, IR780, IR783, IR797, IR806, IR808, IR820, IR825, IRDye 800CW, and Cypate) for cancer photothermal therapy, photodynamic therapy, and imaging. Overall, the continuous development of nanomaterials incorporating the prototypic NIR absorbing heptamethine cyanines will cement their phototheragnostic capabilities.

Mitochondria-targeted nanospheres with deep tumor penetration for photo/starvation therapy

IR780 and GOx based PLGA nanospheres can not only selectively accumulate in mitochondria but penetrate into 3D tumors deeply, achieving synergistic treatment of phototherapy and GOx-induced starvation therapy under dual-imaging guidance/monitoring.