Near-Infrared Light-Sensitive Liposomes for the Enhanced Photothermal Tumor Treatment by the Combination with Chemotherapy

Purpose

To develop a near-infrared (NIR) light-sensitive liposome, which contains hollow gold nanospheres (HAuNS) and doxorubicin (DOX), and evaluate their potential utility for enhancing antitumor activity and controlling drug release.

Methods

The liposomes (DOX&HAuNS-TSL) were designed based on a thermal sensitive liposome (TSL) formulation, and hydrophobically modified HAuNS were attached onto the membrane of the liposomes. The behavior of DOX release from the liposomes was investigated by the dialysis, diffusion in agarose gel and cellular uptake of the drug. The biodistribution of DOX&HAuNS-TSL was assessed by i.v. injection in tumor-bearing nude mice. Antitumor efficacy was evaluated both histologically using excised tissue and intuitively by measuring the tumor size and weight.

Results

Rapid and repetitive DOX release from the liposomes (DOX&HAuNS-TSL), could be readily achieved upon NIR laser irradiation. The treatment of tumor cells with DOX&HAuNS-TSL followed by NIR laser irradiation showed significantly greater cytotoxicity than the treatment with DOX&HAuNS-TSL alone, DOX-TSL alone (chemotherapy alone) and HAuNS-TSL plus NIR laser irradiation (Photothermal ablation, PTA, alone). In vivo antitumor study indicated that the combination of simultaneous photothermal and chemotherapeutic effect mediated by DOX&HAuNS-TSL plus NIR laser presented a significantly higher antitumor efficacy than the PTA alone mediated by HAuNS-TSL plus NIR laser irradiation.

Conclusions

Our study could be as the valuable reference and direction for the clinical application of PTA in tumor therapy.     

Topically applied liposome-in-hydrogels for systematically targeted tumor photothermal therapy

Transdermal drug delivery for local or systemic therapy provides a potential anticancer modality with a high patient compliance. However, the drug delivery efficiency across the skin is highly challenging due to the physiological barriers, which limit the desired therapeutic effects. In this study, we prepared liposome-in-hydrogels containing a tumor targeting photosensitizer IR780 (IR780/lipo/gels) for tumor photothermal therapy (PTT). The formulation effectively delivered IR780 to subcutaneous tumor and deep metastatic sites, while the hydrogels were applied on the skin overlying the tumor or on an area of distant normal skin. The photothermal antitumor activity of topically administered IR780/lipo/gels was evaluated following laser irradiation. We observed significant inhibition of the rate of the tumor growth without any toxicity associated with the topical administration of hydrogels. Collectively, the topical administration of IR780/lipo/gels represents a new noninvasive and safe strategy for targeted tumor PTT.     

Trimodal synergistic antitumor drug delivery system based on graphene oxide

A multifunctional antitumor drug delivery system was synthesized based on graphene oxide (GO) for near-infrared (NIR) light controlling chemotherapeutic/photothermal (PTT) /photodynamic (PDT) trimodal synergistic therapy. The system named ICG-Wed-GO was formed by co-loading wedelolactone (Wed) and indocyanine green (ICG) on the surface of GO through π–π stacking interaction. Under NIR laser irradiation, ICG-Wed-GO could effectively absorb and transform optical energy to heat, generate reactive oxygen species (ROS) to ablating and damage tumor cells. The temperature of ICG-Wed-GO solution reached up to 79.4?°C in 10?min with NIR irradiation. In in vitro and in vivo study, ICG-Wed-GO showed excellent antitumor effect. After 14-day treatment of ICG-Wed-GO with NIR laser irradiation, the tumor disappeared completely on tumor-bearing mice. The low biotoxicity of ICG-Wed-GO was also proved. The system achieved the synergistic trimodal chemotherapeutic/photothermal/photodynamic treatment and demonstrated excellent antitumor effect, which is expected to have a greater potential for cancer therapy.     

Iodinated cyanine dye-based nanosystem for synergistic phototherapy and hypoxia-activated bioreductive therapy

Photodynamic therapy (PDT) has been applied in cancer treatment by utilizing reactive oxygen species (ROS) to kill cancer cells. However, the effectiveness of PDT is greatly reduced due to local hypoxia. Hypoxic activated chemotherapy combined with PDT is expected to be a novel strategy to enhance anti-cancer therapy. Herein, a novel liposome (LCT) incorporated with photosensitizer (PS) and bioreductive prodrugs was developed for PDT-activated chemotherapy. In the design, CyI, an iodinated cyanine dye, which could simultaneously generate enhanced ROS and heat than other commonly used cyanine dyes, was loaded into the lipid bilayer; while tirapazamine (TPZ), a hypoxia-activated prodrug was encapsulated in the hydrophilic nucleus. Upon appropriate near-infrared (NIR) irradiation, CyI could simultaneously produce ROS and heat for synergistic PDT and photothermal therapy (PTT), as well as provide fluorescence signals for precise real-time imaging. Meanwhile, the continuous consumption of oxygen would result in a hypoxia microenvironment, further activating TPZ free radicals for chemotherapy, which could induce DNA double-strand breakage and chromosome aberration. Moreover, the prepared LCT could stimulate acute immune response through PDT activation, leading to synergistic PDT/PTT/chemo/immunotherapy to kill cancer cells and reduce tumor metastasis. Both in vitro and in vivo results demonstrated improved anticancer efficacy of LCT compared with traditional PDT or chemotherapy. It is expected that these iodinated cyanine dyes-based liposomes will provide a powerful and versatile theranostic strategy for tumor target phototherapy and PDT-induced chemotherapy.     

Synergetic delivery of triptolide and Ce6 with light-activatable liposomes for efficient hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) has been known as the second common leading cancer worldwide, as it responds poorly to both chemotherapy and medication. Triptolide (TP), a diterpenoid triepoxide, is a promising treatment agent for its effective anticancer effect on multiple cancers including HCC. However, its clinical application has been limited owing to its severe systemic toxicities, low solubility, and fast elimination in the body. Therefore, to overcome the above obstacles, photo-activatable liposomes (LP) integrated with both photosensitizer Ce6 and chemotherapeutic drug TP (TP/Ce6-LP) was designed in the pursuit of controlled drug release and synergetic photodynamic therapy in HCC therapy. The TP encapsulated in liposomes accumulated to the tumor site due to the enhanced permeability and retention (EPR) effect. Under laser irradiation, the photosensitizer Ce6 generated reactive oxygen species (ROS) and further oxidized the unsaturated phospholipids. In this way, the liposomes were destroyed to release TP. TP/Ce6-LP with NIR laser irradiation (TP/Ce6-LP+L) showed the best anti-tumor effect both in vitro and in vivo on a patient derived tumor xenograft of HCC (PDXHCC). TP/Ce6-LP significantly reduced the side effects of TP. Furthermore, TP/Ce6-LP+L induced apoptosis through a caspase-3/PARP signaling pathway. Overall, TP/Ce6-LP+L is a novel potential treatment option in halting HCC progression with attenuated toxicity.KEY WORDS: Hepatocellular carcinoma, Synergetic delivery, Triptolide, Ce6, Photo-activatable liposomes, Photosensitizer, Process of photodynamic therapy, PDX model     

NIR-triggered thermo-responsive biodegradable hydrogel with combination of photothermal and thermodynamic therapy for hypoxic tumor

Hypoxia is a typical feature of solid tumors, which highly limits the application of the oxygen-dependent therapy. Also, the dense and hyperbaric tumor tissues impede the penetration of nanoparticles into the deep tumor. Thereby, we designed a novel localized injectable hydrogel combining the photothermal therapy (PTT) and the thermodynamic therapy (TDT), which is based on the generation of free radicals even in the absence of oxygen for hypoxic tumor therapy. In our study, gold nanorods (AuNRs) and 2,2′-Azobis[2-(2-imidazalin-2-yl)propane] dihydrochlaride (AIPH) were incorporated into the hydrogel networks, which were formed by the copolymerization of hydrophobic N-isopropyl acrylamide (NIPAM) and hydrophilic glycidyl methacrylate modified hyaluronic acid (HA-GMA) to fabricate an injectable and near-infrared (NIR) responsive hydrogel. The crosslinked in situ forming hydrogel could not only realize PTT upon the NIR laser irradiation, but also generate free radicals even in hypoxic condition. Meanwhile the shrink of hydrogels upon thermal could accelerate the generation of free radicals to further damage the tumors, achieving the controlled drug release on demand. The designed hydrogel with a sufficient loading capacity, excellent biocompatibility and negligible systemic toxicity could serve as a long-acting implant for NIR-triggered thermo-responsive free radical generation. The in vitro cytotoxicity result and the in vivo antitumor activity illustrated the excellent therapeutic effect of hydrogels even in the absence of oxygen. Therefore, this innovative oxygen-independent platform combining the antitumor effects of PTT and TDT would bring a new insight into hypoxic tumor therapy by the application of alkyl free radical.     

Comparing the efficacy of sunitinib with sorafenib in xenograft models of human hepatocellular carcinoma: mechanistic explanation

Hepatocellular carcinoma (HCC) is the fifth most common and third deadliest malignancy. Sorafenib has demonstrated 44% survival advantage over placebo and has emerged as a standard of care in advanced HCC. The therapeutic effects of sorafenib are however transient and hence additional treatment options are warranted. In this study, we aimed to compare the efficacy of sunitinib relative to sorafenib, two potent inhibitors of protein tyrosine kinases involved in tumor growth, metastasis, or angiogenesis. We reported that sorafenib and sunitinib suppressed tumor growth, angiogenesis, cell proliferation, and induced apoptosis in both orthotopic and ectopic models of HCC. However, the antitumor effect of 50 mg/kg sorafenib was greater than that of 40 mg/kg sunitinib. Sorafenib inhibited p-eIF4E Ser209, p-p38 Thr180/Tyr182 and reduced survivin expression. This was not seen with sunitinib. In addition, the antitumor and apoptotic effects of sorafenib, which are associated with upregulation of fast migrating Bim and ASK1 and downregulation of survivin, were greater than that of sunitinib. These observations explained in part the apparent superior anti-tumor activity of sorafenib compared to sunitinib. In conclusion, sunitinib demonstrated an inferior anti-tumor activity compared to sorafenib in ectopic and orthotopic models of human HCC. It remains to be seen whether such observations would be recapitulated in humans.     

主动靶向脂质体在抗肿瘤治疗中的研究进展

主动靶向脂质体给药系统可使抗肿瘤药物与靶组织结合,将药物可控性地分布于靶组织并持续缓慢释药,在提高药物抗癌效果的同时,降低了其对正常组织的不良反应。本文主要介绍了免疫脂质体、受体介导的脂质体、糖基修饰的脂质体及多肽修饰的脂质体等主动靶向脂质体在抗肿瘤研究中的进展。主动靶向脂质体给药系统将会发展为抗肿瘤药物的理想剂型,具有很好的临床应用前景。     

Anti-tumor effect of local injectable hydrogel-loaded endostatin alone and in combination with radiotherapy for lung cancer

Endostatin (ES) can effectively inhibit neovascularization in most solid tumors and has the potential to make oxygen delivery more efficient and increase the efficacy of radiotherapy (RT). With a short half-life, ES is mainly administered systemically, which leads to low intake in tumor tissue and often toxic systemic side effects. In this study, we used hyaluronic acid-tyramine as a carrier to synthesize an ES-loaded hydrogel drug (ES/HA-Tyr) that can be injected locally. ES/HA-Tyr has a longer half-life and fewer systemic toxic side effects, and it exerts a better anti-angiogenic effect and anti-tumor effect with RT. In vitro, ES/HA-Tyr showed sustained release in the release assay and a stronger ability to inhibit the proliferation of human umbilical vascular endothelial cells (HUVECs) in the MTT assay; it exhibited a more potent effect against HUVEC invasion and a stronger anti-angiogenic effect on HUVECs in tube formation. In vivo, ES/HA-Tyr increased local drug concentration, decreased blood drug concentration, and caused less systemic toxicity. Further, ES/HA-Tyr effectively reduced tumor microvessel density, increased tumor pericyte coverage, decreased tumor hypoxia, and increased RT response. ES/HA-Tyr + RT also had increased anti-tumor and anti-angiogenic effects in Lewis lung cancer (LLC) xenograft models. In conclusion, ES/HA-Tyr showed sustained release, lower systemic toxicity, and better anti-tumor effects than ES. In addition, ES/HA-Tyr + RT enhanced anti-angiogenic effects, reduced tumor hypoxia, and increased the efficacy of RT in LLC-bearing mice.     

Tailored core‒shell dual metal–organic frameworks as a versatile nanomotor for effective synergistic antitumor therapy

Malignant tumor has become an urgent threat to global public healthcare. Because of the heterogeneity of tumor, single therapy presents great limitations while synergistic therapy is arousing much attention, which shows desperate need of intelligent carrier for co-delivery. A core‒shell dual metal–organic frameworks (MOFs) system was delicately designed in this study, which not only possessed the unique properties of both materials, but also provided two individual specific functional zones for co-drug delivery. Photosensitizer indocyanine green (ICG) and chemotherapeutic agent doxorubicin (DOX) were stepwisely encapsulated into the nanopores of MIL-88 core and ZIF-8 shell to construct a synergistic photothermal/photodynamic/chemotherapy nanoplatform. Except for efficient drug delivery, the MIL-88 could be functioned as a nanomotor to convert the excessive hydrogen peroxide at tumor microenvironment into adequate oxygen for photodynamic therapy. The DOX release from MIL-88-ICG@ZIF-8-DOX nanoparticles was triggered at tumor acidic microenvironment and further accelerated by near-infrared (NIR) light irradiation. The in vivo antitumor study showed superior synergistic antitumor effect by concentrating the nanoparticles into dissolving microneedles as compared to intravenous and intratumoral injection of nanoparticles, with a significantly higher inhibition rate. It is anticipated that the multi-model synergistic system based on dual-MOFs was promising for further biomedical application.     

Hollow copper sulfide nanoparticles carrying ISRIB for the sensitized photothermal therapy of breast cancer and brain metastases through inhibiting stress granule formation and reprogramming tumor‐associated macrophages

As known, the benefits of photothermal therapy (PTT) are greatly limited by the heat tolerance of cancer cells resulting from overexpressed heat shock proteins (HSPs). Then HSPs further trigger the formation of stress granules (SGs) that regulate protein expression and cell viability under various stress conditions. Inhibition of SG formation can sensitize tumor cells to PTT. Herein, we developed PEGylated pH (low) insertion peptide (PEG-pHLIP)-modified hollow copper sulfide nanoparticles (HCuS NPs) encapsulating the SG inhibitor ISRIB, with the phase-change material lauric acid (LA) as a gate-keeper, to construct a pH-driven and NIR photo-responsive controlled smart drug delivery system (IL@H-PP). The nanomedicine could specifically target slightly acidic tumor sites. Upon irradiation, IL@H-PP realized PTT, and the light-controlled release of ISRIB could effectively inhibit the formation of PTT-induced SG to sensitize tumor cells to PTT, thereby increasing the antitumor effect and inducing potent immunogenic cell death (ICD). Moreover, IL@H-PP could promote the production of reactive oxygen species (ROS) by tumor-associated macrophages (TAMs), repolarizing them towards the M1 phenotype and remodeling the immunosuppressive microenvironment. In vitro/vivo results revealed the potential of PTT combined with SG inhibitors, which provides a new paradigm for antitumor and anti-metastases.     

Tumor-targeted/reduction-triggered composite multifunctional nanoparticles for breast cancer chemo-photothermal combinational therapy

Breast cancer has become the most commonly diagnosed cancer type in the world. A combination of chemotherapy and photothermal therapy (PTT) has emerged as a promising strategy for breast cancer therapy. However, the intricacy of precise delivery and the ability to initiate drug release in specific tumor sites remains a challenging puzzle. Therefore, to ensure that the therapeutic agents are synchronously delivered to the tumor site for their synergistic effect, a multifunctional nanoparticle system (PCRHNs) is developed, which is grafted onto the prussian blue nanoparticles (PB NPs) by reduction-responsive camptothecin (CPT) prodrug copolymer, and then modified with tumor-targeting peptide cyclo(Asp-d-Phe-Lys-Arg-Gly) (cRGD) and hyaluronic acid (HA). PCRHNs exhibited nano-sized structure with good monodispersity, high load efficiency of CPT, triggered CPT release in response to reduction environment, and excellent photothermal conversion under laser irradiation. Furthermore, PCRHNs can act as a photoacoustic imaging contrast agent-guided PTT. In vivo studies indicate that PCRHNs exhibited excellent biocompatibility, prolonged blood circulation, enhanced tumor accumulation, allow tumor-specific chemo-photothermal therapy to achieve synergistic antitumor effects with reduced systemic toxicity. Moreover, hyperthermia-induced upregulation of heat shock protein 70 in the tumor cells could be inhibited by CPT. Collectively, PCRHNs may be a promising therapeutic way for breast cancer therapy.     

Multifunctional liposome for photoacoustic/ultrasound imaging-guided chemo/photothermal retinoblastoma therapy

Retinoblastoma (RB) is a malignant intraocular neoplasm that occurs in children. Diagnosis and therapy are frequently delayed, often leading to metastasis, which necessitates effective imaging and treatment. In recent years, the use of nanoplatforms allowing both imaging and targeted treatment has attracted much attention. Herein, we report a novel nanoplatform folate-receptor (FR) targeted laser-activatable liposome termed FA-DOX-ICG-PFP@Lip, which is loaded with doxorubicin (DOX)/indocyanine green (ICG) and liquid perfluoropentane (PFP) for photoacoustic/ultrasound (PA/US) dual-modal imaging-guided chemo/photothermal RB therapy. The dual-modal imaging capability, photothermal conversion under laser irradiation, biocompatibility, and antitumor ability of these liposomes were appraised. The multifunctional liposome showed a good tumor targeting ability and was efficacious as a dual-modality contrast agent both in vivo and in vitro. When laser-irradiated, the liposome converted light energy to heat. This action caused immediate destruction of tumor cells, while simultaneously initiating PFP phase transformation to release DOX, resulting in both photothermal and chemotherapeutic antitumor effects. Notably, the FA-DOX-ICG-PFP@Lip showed good biocompatibility and no systemic toxicity was observed after laser irradiation in RB tumor-bearing mice. Hence, the FA-DOX-ICG-PFP@Lip shows great promise for dual-modal imaging-guided chemo/photothermal therapy, and may have significant value for diagnosing and treating RB.     

N-三甲基壳聚糖包衣多柔比星脂质体肿瘤新生血管靶向性的体内评价

目的：考察N-三甲基壳聚糖（TMC）包衣的多柔比星（ADM）阳离子脂质体抗肿瘤活性及对肿瘤新生血管的靶向性。方法：采用动物移植性肿瘤实验法,建立小鼠H22肿瘤模型,比较TMC包衣脂质体组和其他各给药组的肿瘤抑制率并通过小鼠尾静脉注射异硫氰酸荧光素标记的葡聚糖（FITC—Dextran）,分析肿瘤组织中的在体荧光,定性观察肿瘤新生血管的形态排布情况,定量测定肿瘤组织中的血管相对密度。结果：TMC包衣的ADM脂质体组,其小鼠的瘤重抑制率迭53．47％,显著高于游离药物组和未包衣脂质体组（8．75％,34．88％）（P〈0．05）;给予TMC包衣ADM脂质体的小鼠,其肿瘤新生血管形态良好,排布均匀,血管分支少,而其他给药组的肿瘤新生血管多扭曲,粗细不均,一个节点有多个血管分支等;通过比较不同给药组肿瘤组织黏附的FITC—Dextran量,TMc包衣ADM脂质体组的肿瘤血管密度明显低于游离药物组和未包衣脂质体组（P〈0．05）。结论：TMC包衣的ADM阳离子脂质体不仅具有较强的抗肿瘤活性,而且具有很好的肿瘤新生血管靶向性。     

载血卟啉单甲醚中空金纳米球的光热光动力联合抗肿瘤研究

目的 设计基于中空金纳米球的新型纳米给药系统(HMME-PEI-HAuNS),在近红外光照射下研究其同步光热光动力联合抗肿瘤作用。方法 以钴纳米粒为模板制备中空金纳米球(HAuNS),将血卟啉单甲醚(HMME)通过枝状聚乙烯亚胺(PEI)装载到HAuNS表面,形成纳米给药系统(HMME-PEI-HAuNS);采用核磁共振氢谱、红外光谱、紫外光谱分析对HMME-PEI-HAuNS进行结构确证。建立荷瘤(SKOV3)小鼠模型,通过荧光活体成像仪考察其体内分布情况。将对肿瘤细胞表面EphB4受体具有特异性亲和力的靶向多肽TNYL修饰于其表面以增强该纳米体系的靶向性,用核染试剂Hoechst染色SKOV3细胞,在激光共聚焦显微镜下观察细胞内的荧光强度,用MTT比色法进行细胞毒性评价。结果 HAuNS能对HMME进行成功装载,装载率达63.4±5.2%。由于肿瘤的高通透性和滞留效应(EPR 效应),HMME-PEI-HAuNS较游离HMME和HMME-PEI胶束在肿瘤部位有更多的累积量和更长的滞留时间,累计效率约为1.6%。荧光定量统计显示在TNYL多肽的介导下纳米球的靶向性更高,在808 nm激光照射下,TNYL-HMME-PEI-HAuNS发挥光热和光动力协同作用产生强大的肿瘤杀伤作用,在高浓度时,细胞存活率不到10%。结论 主动靶向纳米球(TNYL-HMME-PEI-HAuNS)在808 nm近红外光照射下具有较强的光热光动力联合抗肿瘤作用。     

pH-Sensitive Black Phosphorous–Incorporated Hydrogel as Novel Implant for Cancer Treatment

In this study, black phosphorus nanosheets (BPNSs) were incorporated into a hydrogel formed from dibenzaldehyde-functionalized polymer (DF-PEG) and polyaspartylhydrazide (PAHy) polymer to create an injectable and pH-sensitive DF-PEG-PAHy/BPNSs hydrogel, which can be used as a smart depot for synergistic chemo-photothermal cancer therapy. The DF-PEG-PAHy/BPNSs hydrogel exhibited excellent gelation characteristics, pH sensitivity, and near-infrared responsiveness. The nanocomposite hydrogel provided controlled drug release and near-infrared irradiation speeded up release of drug from the hydrogel because of the photothermal effect of the BPNSs. Cytotoxicity tests confirmed that the hydrogel has good biocompatibility and exerts its photothermal effect in vitro. Antitumor tests in mice demonstrated the capacity of DF-PEG-PAHy/BPNSs hydrogel for synergistic chemo-photothermal therapy in vivo. The hydrogel showed reduced adverse effects because of stable drug release in the tumor area and an efficient photothermal effect. Together, these data demonstrated the potential of DF-PEG-PAHy/BPNSs hydrogel containing a chemotherapy drug to serve as a novel smart delivery system for combined chemo-photothermal cancer therapy.     

Sialic acid-mediated photochemotherapy enhances infiltration of CD8+ T cells from tumor-draining lymph nodes into tumors of immunosenescent mice

Immunoscenescence plays a key role in the initiation and development of tumors. Furthermore, immunoscenescence also impacts drug delivery and cancer therapeutic efficacy. To reduce the impact of immunosenescence on anti-tumor therapy, this experimental plan aimed to use neutrophils with tumor tropism properties to deliver sialic acid (SA)-modified liposomes into the tumor, kill tumor cells via SA-mediated photochemotherapy, enhance infiltration of neutrophils into the tumor, induce immunogenic death of tumor cells with chemotherapy, enhance infiltration of CD8⁺ T cells into the tumor-draining lymph nodes and tumors of immunosenescent mice, and achieve SA-mediated photochemotherapy. We found that CD8⁺ T cell and neutrophil levels in 16-month-old mice were significantly lower than those in 2- and 8-month-old mice; 16-month-old mice exhibited immunosenescence. The anti-tumor efficacy of SA-mediated non-photochemotherapy declined in 16-month-old mice, and tumors recurred after scabbing. SA-mediated photochemotherapy enhanced tumor infiltration by CD8⁺ T cells and neutrophils, induced crusting and regression of tumors in 8-month-old mice, inhibited metastasis and recurrence of tumors and eliminated the immunosenescence-induced decline in antitumor therapeutic efficacy in 16-month-old mice via the light-heat-chemical-immunity conversion.     

Preparation,Characterization, and Pharmacodynamics of Thermosensitive Liposomes Containing Docetaxel

A novel thermosensitive liposome (TL) containing docetaxel (DTX) was designed to enhance DTX-targeted delivery and antitumor effect. TL loading DTX (DTX-TL) were prepared by thin film hydration. The mean particle size of the liposomes was about 100 nm, and the drug entrapment efficiency was more than 95%. The phase transition temperature of liposomes was about 42°C. In vitro drug release showed that drug released at 37°C was obviously less than that at 42°C. For in vivo experiments, the human breast tumor model was established by subcutaneous xenotransplantation on nude mice; liposomes and injection containing DTX were injected i.v. in nude mice, followed by exposure of the tumors to hyperthermia (HT) for 30 min after administration. The tumor inhibition ratio of DTX-TL group was significantly higher than the normal injection group. Combining TL with HT enhanced the delivery of DTX and thereby its antitumor effects. The liposomes reported in this paper could potentially produce viable clinical strategies for improved targeting and delivery of DTX for the treatment of breast cancer.     

Near-Infrared Image-Guided Delivery and Controlled Release Using Optimized Thermosensitive Liposomes

Purpose

To engineer optimized near-infrared (NIR) active thermosensitive liposomes to potentially achieve image-guided delivery of chemotherapeutic agents.

Methods

Thermosensitive liposomes were surface-coated with either polyethylene glycol or dextran. Differential scanning calorimetry and calcein release studies were conducted to optimize liposomal release, and flow cytometry was employed to determine the in vitro macrophage uptake of liposomes. Indocyanine green (ICG) was encapsulated as the NIR dye to evaluate the in vivo biodistribution in tumor-bearing mice.

Results

The optimized thermosensitive liposome formulation consists of DPPC, SoyPC, and cholesterol in the 100:50:30 molar ratio. Liposomes with dextran and polyethylene glycol demonstrated similar thermal release properties; however in vitro macrophage uptake was greater with dextran. Non-invasive in vivo NIR imaging showed tumor accumulation of liposomes with both coatings, and ex vivo NIR imaging correlated well with actual ICG concentrations in various organs of healthy mice.

Conclusions

The optimized thermosensitive liposome formulation demonstrated stability at 37?°C and efficient burst release at 40 and 42?°C. Dextran exhibited potential for application as a surface coating in thermosensitive liposome formulations. In vivo studies suggest that liposomal encapsulation of ICG permits reliable, real-time monitoring of liposome biodistribution through non-invasive NIR imaging.     

恩度抗血管生成和在肿瘤血管正常化中的研究进展

实体瘤的生长和转移依赖于肿瘤新生血管生成,由此提出了抗肿瘤血管生成治疗。由于其靶点主要是肿瘤新生血管,因此现已成为抗肿瘤治疗最受瞩目的领域之一。随着对其研究的深入,又指出并非是最大限度抗肿瘤血管生成,而是应该使肿瘤血管正常化,以增加氧供和降低组织间质压力,使化疗药物更好更均匀的进入肿瘤组织内,但是这种正常化是有一定时间限制的。如何将抗血管生成药物和放化疗进一步更好的结合以达到更好的疗效,用更有效更无创的分子影像技术等手段对其进行评价,以便更好的运用于临床将是我们研究的重点。