Nanoparticle-enhanced synergistic HIFU ablation and transarterial chemoembolization for efficient cancer therapy

High-intensity focused ultrasound (HIFU) is being generally explored as a non-invasive therapeutic modality to treat solid tumors. However, the clinical use of HIFU for large and deep tumor-ablation applications such as hepatocellular carcinoma (HCC) is currently entangled with long treatment duration and high operating energy. This critical issue can be potentially resolved by the introduction of HIFU synergistic agents (SAs). Traditional SAs such as microbubbles and microparticles face the problem of large size, short cycle time, damage to mononuclear phagocytic system and unsatisfactory targeting efficiency. In this work, we have developed a facile and versatile nanoparticle-based HIFU synergistic cancer surgery enhanced by transarterial chemoembolization for high-efficiency HCC treatment based on elaborately designed Fe3O4-PFH/PLGA nanocapsules. Multifunctional Fe3O4-PFH/PLGA nanocapsules were administrated into tumor tissues via transarterial injection combined with Lipiodol to achieve high tumor accumulation because transarterial chemoembolization by Lipiodol could block the blood vessels. The high synergistic HIFU ablation effect was successfully achieved against HCC tumors based on the phase-transformation performance of the perfluorohexane (PFH) inner core in the composite nanocapsules, as systematically demonstrated in VX2 liver tumor xenograft in rabbits. Multifunctional Fe3O4-PFH/PLGA nanocapsules were also demonstrated as efficient contrast agents for ultrasound, magnetic resonance and photoacoustic tri-modality imagings, potentially applicable for imaging-guided HIFU synergistic surgery. Therefore, the elaborate integration of traditional transarterial chemoembolization with recently developed nanoparticle-enhanced HIFU cancer surgery could efficiently enhance the HCC cancer treatment outcome, initiating a new and efficient therapeutic protocol/modality for clinic cancer treatment.

Microwave Responsive Nanoplatform via P-Selectin Mediated Drug Delivery for Treatment of Hepatocellular Carcinoma with Distant Metastasis

Hepatocellular carcinoma (HCC) with metastatic disease is associated with a low survival in clinical practice. Many curative options including liver resection, transplantation, and thermal ablation are effective in local but limited for patients with distant metastasis. In this study, the efficacy, specificity, and safety of P-selectin targeted delivery and microwave (MW) responsive drug release is investigated for development of HCC therapy. By encapsulating doxorubicin (DOX) and MW sensitizer (1-butyl-3-methylimidazolium-l-lactate, BML) into fucoidan conjugated liposomal nanoparticles (TBP@DOX), specific accumulation and prominent release of DOX in orthotopic HCC and lung metastasis are achieved with adjuvant MW exposure. This results in orthotopic HCC growth inhibition that is not only 1.95-fold higher than found for nontargeted BP@DOX and 1.6-fold higher than nonstimuli responsive TP@DOX but is also equivalent to treatment with free DOX at a 10-fold higher dose. Furthermore, the optimum anticancer efficacy against distant lung metastasis and effective prevention of widespread dissemination with a prolonged survival is described. In addition, no adverse metabolic events are identified using the TBP@DOX nanodelivery system despite these events being commonly observed with traditional DOX chemotherapy. Therefore, administering TBP@DOX with MW exposure could potentially enhance the therapeutic efficacy of thermal-chemotherapy of HCC, especially those in the advanced stages.

Low-intensity focused ultrasound (LIFU)-activated nanodroplets as a theranostic agent for noninvasive cancer molecular imaging and drug delivery

Theranostics is a new trend in the tumor research field, which involves the integration of diagnostic and therapeutic functions using imageable nanoparticles coupled with therapeutic drugs. Imaging-guided targeted delivery of therapeutics and diagnostics using nanocarriers hold great promise to minimize the side effects of conventional chemotherapy. Ultrasound microbubbles have been employed as theranostic agents over the last decade, which provide both real-time dynamic imaging for diagnosis and precise control for targeted tumor therapy. However, the intrinsic defects of microbubbles such as poor tissue penetration, short circulation time and instability hinder microbubble-based theranostic applications. In recent years, liquid-to-gas transitional perfluorocarbon nanoparticles have been developed as promising diagnostic and therapeutic nanoagents to solve the abovementioned problems. In this study, phase-changeable, folate-targeted perfluoropentane nanodroplets loaded with 10-hydroxycamptothecin (HCPT) and superparamagnetic Fe3O4 (denoted as FA-HCPT-Fe3O4-PFP NDs) are prepared and investigated for multimodal tumor imaging and targeted therapy. After intravenous administration into nude mice bearing SKOV3 ovarian cancer, FA-HCPT-Fe3O4-PFP NDs exhibit the ability to enhance MR and PA imaging. Furthermore, after the phase transition activated by low-intensity focused ultrasound (LIFU) sonication, FA-HCPT-Fe3O4-PFP NDs remarkably enhance US imaging at the tumor location. Meanwhile, the HCPT released from FA-HCPT-Fe3O4-PFP NDs during the liquid-to-gas transition provides a therapeutic effect on tumor cells with relatively low side effects to normal tissue. Therefore, the combination of LIFU and FA-HCPT-Fe3O4-PFPNDs presents an ideal modality for tumor-targeted theranostics.

Magnetic Hyperthermia Ablation of Tumors Using Injectable Fe₃O₄/Calcium Phosphate Cement

In this work, we have developed an injectable and biodegradable material using CPC containing Fe3O4 nanoparticles for minimally invasive and efficiently magnetic hyperthermia ablation of tumors. When exposed to an alternating magnetic field, the MCPC could quickly generate heat. The temperature of PBS and the excised bovine liver increased with the MCPC weight, iron content, and time. The ablated liver tissue volume for 0.36 g of 10% MCPC was 0.2 ± 0.03, 1.01 ± 0.07, and 1.96 ± 0.19 cm(3), respectively, at the time point of 60, 180, and 300 s. In our in vivo experiment, the MCPC could be directly injected into the center of the tumors under the guidance of ultrasound imaging. The formed MCPC was well-restricted within the tumor tissues without leakage, and the tumors were completely ablated by 0.36 g of 10% injectable MCPC after 180 s of induction heating.

Multifunctional pathology-mapping theranostic nanoplatforms for US/MR imaging and ultrasound therapy of atherosclerosis

Atherosclerotic thrombosis is the leading cause of most life-threatening cardiovascular diseases (CVDs), particularly as a result of rupture or erosion of vulnerable plaques. Rupture or erosion-prone plaques are quite different in cellular composition and immunopathology, requiring different treatment strategies. The current imaging technology cannot distinguish the types of vulnerable plaques, and thus empirical treatment is still applied to all without a tailored and precise treatment. Herein, we propose a novel strategy called "Multifunctional Pathology-mapping Theranostic Nanoplatform (MPmTN)" for the tailored treatment of plaques based on the pathological classification. MPmTNs are made up of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), containing contrast imaging materials Fe3O4 and perfluoropentane (PFP), and coated with specific plaque-targeted peptides PP1 and cyclic RGD. The PFP encapsulated inside the MPmTN can undergo a phase change from nanodroplets to gas microbubbles under therapeutic ultrasound (TUS) exposure. The acoustic and biological effects induced by TUS and disruption of microbubbles may further promote therapeutic effects. Hypothetically, MPmTN NPs can target the rupture-prone plaque via the binding of PP1 to class A scavenger receptors (SR-A) on macrophages, induce the apoptosis due to TUS exposure and thus reduce the chronic soakage of inflammatory cells. The MPmTN NPs can also target the erosion-prone plaque through the binding of cRGD to glycoprotein (GP) IIb/IIIa on activated platelets and promote platelet disaggregation under TUS exposure. Therefore, MPmTNs may work as a multifunctional pathology-mapping therapeutic agent. Our in vitro results show that the MPmTN with PP1 and cRGD peptides had a high binding affinity both for activated macrophages and blood clots. Under TUS exposure, the MPmTN could effectively induce macrophage apoptosis, destroy thrombus and exhibit good imaging properties for ultrasound (US) and MRI. In apoE-/- mice, MPmTNs can selectively accumulate at the plaque site and reduce the T2-weighted signal. The apoptosis of macrophages and disaggregation of activated platelets on the plaques were also confirmed in vivo. In summary, this study provides a potential strategy for a tailored treatment of vulnerable plaques based on their pathological nature and a multimodal imaging tool for the risk stratification and assessment of therapeutic efficacy.

Phase-transitional Fe3O4/perfluorohexane Microspheres for Magnetic Droplet Vaporization

Activating droplets vaporization has become an attractive strategy for ultrasound imaging and physical therapy due to the significant increase in ultrasound backscatter signals and its ability to physically damage the tumor cells. However, the current two types of transitional droplets named after their activation methods have their respective limitations. To circumvent the limitations of these activation methods, here we report the concept of magnetic droplet vaporization (MDV) for stimuli-responsive cancer theranostics by a magnetic-responsive phase-transitional agent. This magnetic-sensitive phase-transitional agent-perfluorohexane (PFH)-loaded porous magnetic microspheres (PFH-PMMs), with high magnetic-thermal energy-transfer capability, could quickly respond to external alternating current (AC) magnetic fields to produce thermal energy and trigger the vaporization of the liquid PFH. We systematically demonstrated MDV both in vitro and in vivo. This novel trigger method with deep penetration can penetrate the air-filled viscera and trigger the vaporization of the phase-transitional agent without the need of pre-focusing lesion. This unique MDV strategy is expected to substantially broaden the biomedical applications of nanotechnology and promote the clinical treatment of tumors that are not responsive to chemical therapies.

Microwave-activated nanodroplet vaporization for highly efficient tumor ablation with real-time monitoring performance

The fast development of nanotechnology has provided a new efficient strategy for enhancing the therapeutic efficiency of various treatment modalities against cancer. However, the improvement of minimally invasive microwave therapy based on nanomaterials has not been realized. In this work, we successfully designed and synthesized a novel folate-targeted nanodroplet (TPN) with a composite mixture of perfluorocarbons as the core and lipid as the shell, which exerts the distinctive dual functions as the adjuvant for highly efficient percutaneous ultrasound imaging-guided microwave ablation (MWA) of tumors. Based on the unique phase-changeable performance of TPN nanosystem, a novel microwave-droplet vaporization (MWDV) strategy was proposed, for the first time, to overcome the critical issues of traditional acoustic-droplet vaporization (ADV) and optical-droplet vaporization (ODV) for cancer theranostics. Especially, the elaborately designed TPN can overcome the challenges of indistinct imaging of ablation margin and the limited ablation zone of MWA modality against cancer. The high efficiency of this new MWDV strategy has been systematically elucidated in vitro, ex vivo and in vivo. Therefore, such a successful demonstration of the role of nanomaterials (TPN in this case) in ultrasound imaging-guided MWA therapy against cancer provides a highly feasible strategy to effectively enhance the MWA outcome with the specific features of high efficiency and biosafety.

Review of clinical tumor ablation advance in Asia

Tumor ablation has been widely applied in Asia, accounting for 44.65% of clinical studies worldwide. We reviewed 5853 clinical studies to provide insight on the advance of tumor ablation in Asia chronologically and geographically among different techniques and organs. Since 1998, tumor ablation application has dramatically evolved in Asia. All kinds of ablation techniques, including percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), microwave ablation (MWA), laser ablation (LA), cryoablation (CA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE), have been applied, with the first application of PEI and the most popular application of RFA. Twenty-five countries and one district in Asia have applied tumor ablation in various organs, including liver, lung, uterus, thyroid, kidney, pancreas, bone, prostate, breast, adrenal gland, lymph node parathyroid, esophagus, etc. Due to the high incidence of tumors as well as advanced economy and technology, East Asia accounted for 93.87% of studies, led by China (45.00%), Japan (32.72%), South Korea (12.10%), and Taiwan (4.03%). With the enrichment of evidence from large-scale multicenter and randomized control studies, China and South Korea have issued several guidelines on tumor ablation for liver, lung, and thyroid, which provided recommendations for global standardization of tumor ablation techniques. Therefore, Asia has made active contribution to global tumor ablation therapy.KeypointsKey point 1: Asia accounted for 44.65% of clinical studies worldwide on tumor ablation.Key point 2: Twenty-five countries and one district in Asia have used tumor ablation in various organs, and East Asia accounted for 93.87% of studies, led by China (45.00%), Japan (32.72%), South Korea (12.10%), and Taiwan (4.03%).Key point 3: China and South Korea have issued several guidelines on tumor ablation for liver, lung, and thyroid, which provided recommendations for global standardization of tumor ablation techniques.

Comparison of the synergistic effect of lipid nanobubbles and SonoVue microbubbles for high intensity focused ultrasound thermal ablation of tumors

Microbubbles (MBs) are considered as an important enhancer for high intensity focused ultrasound (HIFU) treatment of benign or malignant tumors. Recently, different sizes of gas-filled bubbles have been investigated to improve the therapeutic efficiency of HIFU thermal ablation and reduce side effects associated with ultrasound power and irradiation time. However, nanobubbles (NBs) as an ultrasound contrast agent for synergistic therapy of HIFU thermal ablation remain controversial due to their small nano-size in diameter. In this study, phospholipid-shell and gas-core NBs with a narrow size range of 500-600 nm were developed. The synergistic effect of NBs for HIFU thermal ablation was carefully studied both in excised bovine livers and in breast tumor models of rabbits, and made a critical comparison with that of commercial SonoVue microbubbles (SonoVue MBs). In addition, the pathological changes of the targeted area in tumor tissue after HIFU ablation were further investigated. Phosphate buffer saline (PBS) was used as the control. Under the same HIFU parameters, the quantitative echo intensity of B-mode ultrasound image and the volume of coagulative necrosis in lipid NBs groups were significantly higher and larger than that in PBS groups, but could not be demonstrated a difference to that in SonoVue MBs groups both ex vivo and in vivo. These results showed that the synergistic effect of lipid NBs for HIFU thermal ablation were similar with that of SonoVue MBs, and further indicate that lipid NBs could potentially become an enhancer for HIFU thermal ablation of tumors.

Diagnosis of steatohepatitis and fibrosis in biopsy-proven nonalcoholic fatty liver diseases: including two-dimension real-time shear wave elastography and noninvasive fibrotic biomarker scores

BACKGROUND

The aim of this retrospective study was to evaluate the accuracy of two-dimension real-time shear wave elastography (2D-SWE) for the diagnosis of steatohepatitis and fibrosis in a cohort patients confirmed nonalcoholic fatty liver diseases (NAFLD) by liver biopsy, and compare with four noninvasive fibrotic biomarker scores (NFS, FIB-4, BARD and APRI).

METHODS

116 NAFLD patients and 23 normal control group were enrolled. The diagnostic performance of 2D-SWE and four noninvasive fibrotic biomarker scores was evaluated based on histopathological inflammation grades and fibrosis stages (F) according to Kleiner/Brunt et al.'s criteria classification. 5-fold cross validation and receiver operating characteristics curve (ROC) analyses were used to obtain an assessment of 2D-SWE and four noninvasive fibrotic biomarker scores; then cross validated area under the curves (AUCs) were compared using the test of Delong. Meanwhile, influence of steatosis on liver stiffness measurement (LSM) of 2D-SWE was also studied.

RESULTS

Liver stiffness measured by 2D-SWE proved to be an excellent diagnostic indicator for detecting steatohepatitis (AUROC =0.88), and fibrosis: ≥F2 stage (AUROC =0.86), ≥F3 stage (AUROC =0.89) and =F4 stage (AUROC =0.90) with the cutoff values were 7.3, 10.0, 11.6 and 12.6 kPa, respectively. Compared with fibrotic scores, 2D-SWE had the highest AUROC for predicting ≥F2, ≥F3, =F4 by Delong test (all P<0.05). No statistic differences of LSM were found among different steatosis levels (P=0.97).

CONCLUSIONS

The stiffness measured by 2D-SWE could be used to noninvasively identify steatohepatitis and stage fibrosis in NAFLD patients. Moreover, the diagnosis efficiency of the stiffness measured by 2D-SWE could not be influenced by steatosis.

Value of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Focal Splenic Lesions

PURPOSE

To identify and validate contrast-enhanced ultrasound (CEUS) features for differentiating malignant from benign splenic lesions.

PATIENTS AND METHODS

Splenic lesions in 123 patients who underwent conventional ultrasound (B-mode US) and CEUS were included in this study. Two radiologists evaluated the sonograms of B-mode and CEUS. Statistical analysis was performed to identify significant imaging predictors for splenic malignant lesions. Two other radiologists independently reviewed B-mode and CEUS sonograms and diagnosed the lesions based on proposed criteria as 1) benign, 2) probably benign, 3) probably malignant or 4) malignant. The diagnostic efficiency between B-mode US and CEUS was compared.

RESULTS

Common imaging findings of malignant lesions included hypoechoic, ill-defined margin, absence of cystic/necrotic portion, presence of splenomegaly on B-mode US, and hypoenhancement, rapid washout and presence of intralesional vessels on CEUS (P < 0.05). Among them, three independent features were identified using multivariate logistic regression analysis: hypoechoic pattern, hypoenhancement pattern and intralesional vessels. When three of these findings were combined as a predictor for splenic malignant lesions, 22 (55.0%) of 40 malignant splenic lesions were identified with a specificity of 100%. The diagnostic performance of two readers using receiver operating characteristic curve analysis was 0.622 and 0.533, respectively, for B-mode US, which was significantly improved to 0.908 and 0.906 for CEUS (P < 0.001). The degree of other diagnostic efficiency and inter-reader agreement also increased with CEUS compared to B-mode US.

CONCLUSION

CEUS may provide more useful information than B-mode US and improve the diagnosis efficiency for distinguishing malignant from benign splenic lesions.

Microwave ablation of benign breast tumors: a prospective study with minimum 12 months follow-up

PURPOSE

This prospective study was to evaluate clinical outcomes of microwave ablation (MWA) of benign breast tumors with minimum 12 months follow up.

METHODS

With approval of the institutional ethics committee and written informed consent, 56 patients with 107 biopsy-proved breast benign tumors were recruited from November, 2013 to April, 2017. MWA with ultrasound (US) guidance was performed under local anesthesia. During the procedure, pull-back technique was used for tumors larger than 1.0 cm in diameter and hydro-dissection technique was used for tumors adjacent to skin, pectoralis and areola. Clinical outcomes were followed up by physical examination and medical images including US, contrast enhanced US and MR.

RESULTS

The maximum diameter of these tumors was 1.6 ± 0.8 cm. MWA was successfully performed with the median 120 s of duration (ranging 20-1100 s). Technical success was achieved in all patients. At the median follow-up of 20.5 months (ranging 12-53 months), the mean volume reduction ratios (mVRRs) of tumors were 77.1 ± 8.2%, 84.3 ± 10.6%, 93.3 ± 8.2% at follow-up of 12, 18, 24 months (p < .0001), respectively. Compared with 92% of masses were palpable before ablation, mass palpabilities were 40%, 11%, 5% at follow-up of 12, 18, 24 months (p < .001), respectively. Cosmetic satisfaction was reported excellent or good in 100% of patients.

CONCLUSIONS

As a safe and effective minimally invasive modality for inactivating benign breast tumors in situ, MWA achieved optimistic clinical outcomes on volume reduction and cosmetic satisfaction after minimum 12 months follow-up.

Ultrasound mediated delivery of oxygen and LLL12 loaded stimuli responsive microdroplets for the treatment of hypoxic cancer cells

LLL12 exhibits high specificity for inhibiting STAT3 phosphorylation and dimerization, and inducing apoptosis to constitutively activated STAT3 cancer cells without cytotoxicity to normal cells with dormant STAT3. However, clinical deployment of LLL12 in cancer treatment is hindered by its low bioavailability and hypoxia-induced resistance. To overcome these limitations, we encapsulate both oxygen and LLL12 in stimuli responsive microdroplets (SRMs) by a gas-driven coaxial flow focusing (CFF) process for ultrasound mediated treatment of hypoxic cancer cells. Our benchtop experiments demonstrate that the CFF process is able to produce SRMs with uniform size distribution, large oxygen loading capacity, high LLL12 encapsulation efficiency, well protection of bioactivity, and steadily long shelf time. The in vitro therapeutic studies in pancreatic cancer cells (PANC-1 and CAPAN-1) demonstrate the immediate release of oxygen and LLL12 in exposure to therapeutic ultrasound pulses as well as the improved anticancer effects under hypoxic conditions. The findings suggest that the proposed oxygen and LLL12 loaded SRMs provide a promising drug delivery strategy for more effective treatment of hypoxic cancer cells.

Is Additional Systematic Biopsy Necessary in All Initial Prostate Biopsy Patients With Abnormal MRI?

PURPOSE

To determine whether additional systematic biopsy is necessary in all biopsy naïve patients with MRI visible lesions by taking PI-RADS score and prostate volume into consideration.

MATERIALS AND METHODS

Patients who underwent combined systematic biopsy (SB) and cognitive MRI-targeted biopsy (TB) in our hospital between May 2018 and June 2020 were retrospectively reviewed. The detection rate of clinical significant prostate cancer (csPCa), biopsy grade group (GG) concordance, and disease upgrading rate on radical prostatectomy were compared between SB and TB and further stratified by PI-RADS v2.0 category and prostate volume.

RESULTS

A total of 234 patients were analyzed in this study. TB alone detected more csPCa and less clinically insignificant prostate cancer (cisPCa) than SB alone in the whole cohort (57.3 vs 53%, P = 0.041; 3.8 vs 7.7%, P = 0.049 respectively). The additional SB indicated only a marginal increase of csPCa detection but a remarkable increase of cisPCa detection compared with targeted biopsy (59.4 vs 57.3%, P = 0.064; 3.8 vs 7.7%, P = 0.012). As stratified by PI-RADS category, the difference of csPCa detection rate between TB and SB was not significant either in PI-RADS 5 subgroup (83.8 vs 76.3%, P = 0.07) or in PI-RADS 3-4 subgroup (43.5 vs 40.9%, P = 1.0). Additional SB decreased the rate of disease upgrading on radical prostatectomy (RP) than TB alone in PI-RADS 3-4 subgroup (14.5 vs 25.5%, P = 0.031) other than PI-RADS 5 subgroup (6 vs 6%, P = 1.0). When stratified by prostate volume (PV), TB alone detected more csPCa than SB in small prostate (PV < 30 ml) group (81.0 vs 71.0%, P = 0.021) but not in large prostate (PV ≥ 30 ml) group (44.0 vs 42.7%, P = 0.754). The additional SB did not significantly decrease the rate of disease upgrading on RP than TB alone in either small or large prostate (6.4 vs 8.5%, P = 1.0; 13.8 vs 22.4%, P = 0.063).

CONCLUSION

The combination biopsy method was no superior than targeted biopsy alone in PI-RADS 5 or in small volume prostate subgroup.

Theranostic liposomes as nanodelivered chemotherapeutics enhanced the microwave ablation of hepatocellular carcinoma

Aim: This study aimed to develop indocyanine green- and doxorubicin-loaded liposomes (DILPs) as theranostic nanoplatform for the detection of hepatocellular carcinoma (HCC) and as an efficient chemotherapeutic to enhance microwave ablation. Materials & methods: DILPs were synthesized and thoroughly characterized. Biocompatibility, tumor uptake and accumulation, and synergistic ablation-chemotherapeutic efficiency were systematically explored in them. In addition, human HCC surgical samples were used to test the affinity of DILPs for HCC. Results: The combination of microwave ablation and DILPs enhanced the ablation efficiency of HCC with apparent tumor inhibition. DILPs exhibited excellent diagnostic ability and could detect 2.5-mm HCC lesions via optoacoustic tomography imaging. DILPs had better affinity for human HCC surgical samples compared with normal liver tissue. Conclusion: Theranostic DILPs could serve as promising nanoparticles for treatment and management of HCC in the clinic.

Synergistic Cascade Strategy Based on Modifying Tumor Microenvironment for Enhanced Breast Cancer Therapy

Background: Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with very few treatment options. Although tumor-targeted nanomedicines hold great promise for the treatment of TNBC, the tumor microenvironment (TME) continues to be a major cause of failure in nanotherapy and immunotherapy. To overcome this barrier, we designed a new synergistic cascade strategy (SCS) that uses mild hyperthermia and smart drug delivery system (SDDS) to alter TME resistance in order to improve drug delivery and therapeutic efficacy of TNBC. Methods: Mild hyperthermia was produced by microwave (MW) irradiation. SDDS were formulated with thermosensitive polymer-lipid nanoparticles (HA-BNPs@Ptx), composed of polymer PLGA, phospholipid DPPC, hyaluronic acid (HA, a differentiation-44-targeted molecule, also known as CD44), 1-butyl-3-methylimidazolium-L-lactate (BML, a MW sensitizer), and paclitaxel (Ptx, chemotherapy drug). 4T1 breast tumor-bearing mice were treated with two-step MW combined with HA-BNPs@Ptx. Tumors in mice were pretreated with first MW irradiation prior to nanoparticle injection to modify and promote TME and promoting nanoparticle uptake and retention. The second MW irradiation was performed on the tumor 24 h after the injection of HA-BNPs@Ptx to produce a synergistic cascade effect through activating BML, thus, enhancing a hyperthermia effect, and instantly releasing Ptx at the tumor site. Results: Multifunctional CD44-targeted nanoparticles HA-BNPs@Ptx were successfully prepared and validated in vitro. After the first MW irradiation of tumors in mice, the intratumoral perfusion increased by two times, and the nanoparticle uptake was augmented by seven times. With the second MW irradiation, remarkable antitumor effects were obtained with the inhibition rate up to 88%. In addition, immunohistochemical analysis showed that SCS therapy could not only promote tumor cell apoptosis but also significantly reduce lung metastasis. Conclusion: The SCS using mild hyperthermia combined with SDDS can significantly improve the efficacy of TNBC treatment in mice by modifying TME and hyperthermia-mediated EPR effects.

Combination of microbubbles and diagnostic ultrasound at a high mechanical index for the synergistic microwave ablation of tumours

OBJECTIVES

To determine whether combining microbubbles (MBs) with diagnostic ultrasound (US) at a high mechanical index (MI) could enhance the microwave (MW) ablation of tumours.

MATERIALS AND METHODS

Five therapeutic MW adjuvant protocols were studied: MW, MW + US, MW + US + MB, MW + US + NS (saline) and MW + MB. In 30 normal rabbit livers, the synergistic effects were evaluated via temperature, necrosis volume and histology. In 90 VX2 rabbit hepatic tumours, residual cells in the peripheral ablated tumours were examined via immunohistochemical assay and tumour growth. Additional 40 VX2 hepatic tumours were evaluated for ablation safety via blood assay and weight and for survival to 105 days. Results were compared using analysis of variance.

RESULTS

Compared with the other protocols, the ablation volumes in normal rabbit livers were significantly larger using the MW + US + MB protocol (p < .001). The histological examination was consistent with more efficient ablation in that protocol. In detecting residual cells, the apoptotic index was higher, the proliferating index was lower (p < .05), tumour growth was significantly smaller (p < .001), and the rabbits of the MW + US + MB T-Group survived longer (p < .05) than those of the other groups. Additionally, no damage to the liver function or blood cells was found in any of the protocols after ablation (p < .05).

CONCLUSIONS

MBs in combination with diagnostic US at a high MI showed potential synergy in the MW ablation of tumours in rabbits.

Artificial pneumothorax improves radiofrequency ablation of pulmonary metastases of hepatocellular carcinoma close to mediastinum

BACKGROUND

To investigate the feasibility, safety and efficacy of percutaneous radiofrequency ablation (RFA) of pulmonary metastases from hepatocellular carcinoma (HCC) contiguous with the mediastinum using the artificial pneumothorax technique.

METHOD

A total of 40 lesions in 32 patients with pulmonary metastases from HCC contiguous with the mediastinum accepted RFA treatment from August 2014 to May 2018 via the artificial pneumothorax technique. After ablation, clinical outcomes were followed up by contrast enhanced CT. Technical success, local tumor progression (LTP), intrapulmonary distant recurrence (IDR), and adverse events were evaluated. Overall survival (OS) and local tumor progression free survival (LTPFS) were recorded for each patient.

RESULTS

The tumor size was 1.4 ± 0.6 cm in diameter. RFA procedures were all successfully performed without intra-ablative complications. Technical success was noted in 100% of the patients. Five cases of LTP and 8 cases of IDR occurred following the secondary RFA for treatment. Slight pain was reported in all patients. No major complications were observed. The 1, 2, and 3-year LTPFS rates were 90.6, 81.2, and 71.8%, and the 1, 2, and 3-year OS rates were 100, 100 and 87.5%, respectively.

CONCLUSION

Artificial pneumothorax adjuvant RFA is a feasible, safe, and efficient method for treatment of pulmonary metastases from HCC contiguous with the mediastinum.

Dual-modal magnetic resonance and photoacoustic tracking and outcome of transplanted tendon stem cells in the rat rotator cuff injury model

Stem cells have been used to promote the repair of rotator cuff injury, but their fate after transplantation is not clear. Therefore, contrast agents with good biocompatibility for labeling cell and a reliable technique to track cell are necessary. Here, we developed a micron-sized PLGA/IO MPs to label tendon stem cells (TSCs) and demonstrated that PLGA/IO MPs were safe and efficient for long-term tracking of TSCs by using dual-modal MR and Photoacoustic (PA) imaging both in vitro and in rat rotator cuff injury. Moreover, TSCs improved the repair of injury and the therapeutic effect was not affected by PLGA/IO MPs labeling. We concluded that PLGA/IO particle was a promising dual-modal MR/PA contrast for noninvasive long-term stem cell tracking.

Volume reduction for ≥2 cm benign breast lesions after ultrasound-guided microwave ablation with a minimum 12-month follow-up

OBJECTIVE

To prospectively evaluate the efficacy of microwave ablation (MWA) for benign breast lesions (BBLs) ≥2 cm and explore the possible factors associated with the volume reduction rate (VRR) of ablated lesions.

MATERIALS AND METHODS

From November 2013 to December 2017, a total of 80 patients with 104 biopsy-proved BBLs larger than 2 cm in size underwent MWA. After the procedure, patients were followed up via physical and imaging examination consisting of contrast-enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI). Possible factors associated with 12-month VRR were assessed, including basic patient characteristics, index lesions and parameters of ablation technique.

RESULTS

The mean tumor size was 2.6 ± 0.6 cm (ranging 2.0-6.3 cm). Of the 104 lesions, 70 were fibroadenomas, 27 adenosis and 7 fibrocystic changes. Post-procedure CEUS or contrast-enhanced MRI showed that all lesions were completely ablated. No immediate or delayed complications were observed. All patients were followed up for more than 12 months (median follow-up 12.5 months). After MWA, the ablated lesion volume decreased significantly by 12 months (p < 0.001), with a mean volume reduction of 80.2 ± 13.1%. Multiple linear regression analysis showed that location adjacent to areola (β = 7.5, 95%CI: 1.0-13.9, p = 0.025) and location adjacent to skin (β = -7.4, 95%CI: -12.7 to -13.9, p = 0.007) were independent factors respectively associated with the increased and decreased 12-month VRR.

CONCLUSION

For BBLs larger than 2 cm, US-guided MWA is a favorable treatment modality, with BBLs adjacent to the areola being associated with more significant 12-month VRR after MWA.

An Oxygen-Sufficient Nanoplatform for Enhanced Imaging-Guided Microwave Dynamic Therapy Against Hypoxic Tumors

BACKGROUND

Microwave dynamic therapy (MDT) as a novel reactive oxygen species (ROS)-based therapeutic modality has been explored as a promising modality for cancer treatment. However, the intrinsic hypoxic tumor microenvironment (TME) restricted the effectiveness of the MDT. The aim of this study is to develop an oxygen-sufficient nanoplatform with multi-modal imaging capability for enhanced MDT against hypoxic tumors.

METHODS AND MATERIALS

The liquid perfluorocarbon-based nanoplatform PFP@IR780@O2 was constructed by the phospholipid hydration and sonication method. Then, the characteristics, intracellular uptake process, and subcellular localization of PFP@IR780@O2 were verified. Additionally, the abilities of ROS generation, the anti-hypoxia capability, multi-mode imaging capabilities, and MDT efficacy of the nanoplatform were evaluated via in vitro and in vivo experiments. Finally, the in vivo biocompatibility and toxicity were also evaluated.

RESULTS

The prepared nanoparticles PFP@IR780@O2 exhibited suitable size, improved stability, elevated dissolved oxygen level, enhanced cellular uptake, and mitochondria targeting capacity. Additionally, PFP@IR780@O2 demonstrated in vitro and in vivo multimodal imaging capabilities involving ultrasound, fluorescence, and photoacoustic imaging. In vivo studies also indicated that nanoparticles were safe and capable of accumulating in the tumor site after intravenous injection. Furthermore, the PFP@IR780@O2 nanoplatform mediated MDT could effectively alleviate the hypoxic TME, and elevate ROS concentration, thereby resulting in significant tumor growth inhibition.

CONCLUSION

Overall, the oxygen-sufficient nanoplatform with multi-bimodal imaging capability demonstrated improved MDT efficiency, indicating a promising strategy for treating hypoxic tumors.

Improvement of TNBC immune checkpoint blockade with a microwave-controlled ozone release nanosystem

Despite revolutionary achievements have been made in clinical cancer therapy, the immune checkpoint blockade regimen still presents limited efficacy on tumors lack of neoantigens exposure. Here, we designed and synthesized an on-demand microwave-controlled ozone release nanosystem to specifically generate reactive oxygen species in tumor mass. By taking advantage of iRGD modification, the synthesized nanosystem can be specifically enriched in the tumor microenvironment and subsequently internalized by tumor cells. Triggered by the low-power microwave, ozone was released from the nanocarriers and inhibited tumor cell growth in vitro and in vivo. Molecular mechanism investigation further unraveled that the released-ozone induced cytolytic cell death through the rapid generation of reactive oxygen species such as hydroxyl radical. The tumor-specific neoantigen derived from this immunogenic cell death promoted cytotoxic T-lymphocytes infiltration, which provided a fundament for immune checkpoint blockade therapy. In the triple-negative breast cancer animal model, tumor-specific delivery of ozone significantly improved the systematical anti-tumor efficacy of the PD-1 blockade antibody. Notably, tumor-locally confined microwave-controlled release avoided systematic toxicity in the tested animals. Collectively, our nanosystem provides a novel controllable strategy for promoting immune checkpoint blockade therapy, especially in tumor types deficient in infiltrated T-lymphocytes.