The Effect of Docetaxel-Loaded Micro-Bubbles Combined with Low-Frequency Ultrasound in H22 Hepatocellular Carcinoma-Bearing Mice

Quantitative Pharmacokinetics Reveal Impact of Lipid Composition on Microbubble and Nanoprogeny Shell Fate

Microbubble-enabled focused ultrasound (MB-FUS) has revolutionized nano and molecular drug delivery capabilities. Yet, the absence of longitudinal, systematic, quantitative studies of microbubble shell pharmacokinetics hinders progress within the MB-FUS field. Microbubble radiolabeling challenges contribute to this void. This barrier is overcome by developing a one-pot, purification-free copper chelation protocol able to stably radiolabel diverse porphyrin-lipid-containing Definity® analogues (pDefs) with >95% efficiency while maintaining microbubble physicochemical properties. Five tri-modal (ultrasound-, positron emission tomography (PET)-, and fluorescent-active) [64 Cu]Cu-pDefs are created with varying lipid acyl chain length and charge, representing the most prevalently studied microbubble compositions. In vitro, C16 chain length microbubbles yield 2-3x smaller nanoprogeny than C18 microbubbles post FUS. In vivo, [64 Cu]Cu-pDefs are tracked in healthy and 4T1 tumor-bearing mice ± FUS over 48 h qualitatively through fluorescence imaging (to characterize particle disruption) and quantitatively through PET and γ-counting. These studies reveal the impact of microbubble composition and FUS on microbubble dissolution rates, shell circulation, off-target tissue retention (predominantly the liver and spleen), and FUS enhancement of tumor delivery. These findings yield pharmacokinetic microbubble structure-activity relationships that disrupt conventional knowledge, the implications of which on MB-FUS platform design, safety, and nanomedicine delivery are discussed.

Target tumor therapy in human gastric cancer cells through the combination of docetaxel-loaded cationic lipid microbubbles and ultrasound-triggered microbubble destruction

It is well accepted that ultrasound-induced microbubble (USMB) cavitation is a promising method for drug delivery. Ultrasound-targeted destruction of cytotoxic drug-loaded lipid microbubbles (LMs) is used to promote the treatment of cancer. This study aimed to investigate the antitumor effects from a combination of docetaxel-loaded cationic lipid microbubbles (DLLM⁺) and ultrasound (US)-triggered microbubble destruction (UTMD) on gastric cancer (GC). It was found that the functional dose of DOC in this study was 1 × 10^-9 mol/L. We found that DLLM combined with the UTMD group showed greater growth inhibition of the cultured human gastric cancer cells (HGCCs) when compared with the other five groups by arresting the G₂/M phase in the cell cycle. However, DLLM⁺ combined with UTMD showed a higher inhibition rate of tumor growth than DLLM combined with UTMD and that of the RC/CMV-p16 combined with UTMD in vitro and in vivo experiments. DLLM⁺ combined with UTMD significantly suppressed proliferation and promoted the apoptosis of HGCCs with more cells arrested in the G₂/M phase. In addition, DLLM⁺ combined with UTMD suppressed the proliferation and induced apoptosis by arresting cells in the G₂/M phase, which led to a great inhibition of GC progression. Thus, our results indicated that the combination of DLLM⁺ and UTMD might represent a novel and promising approach to chemotherapy for GC.

Delivery of anti-cancer drugs using microbubble-assisted ultrasound in digestive oncology: From preclinical to clinical studies

INTRODUCTION

The combination of microbubbles (MBs) and ultrasound (US) is an emerging method for the noninvasive and targeted enhancement of intratumor chemotherapeutic uptake. This method showed an increased local drug extravasation in tumor tissue while reducing the systemic adverse effects in various tumor models.

AREA COVERED

We focused on preclinical and clinical studies investigating the therapeutic efficacy and safety of this technology for the treatment of colorectal, pancreatic and liver cancers. We discussed the limitations of the current investigations and future perspectives.

EXPERT OPINION

The therapeutic efficacy and the safety of delivery of standard chemotherapy regimen using MB-assisted US have been mainly demonstrated in subcutaneous models of digestive cancers. Although some clinical trials on pancreatic ductal carcinoma and hepatic metastases from various digestive cancers have shown promising results, successful evaluation of this method in terms of US settings, chemotherapeutic schemes and MBs-related parameters will need to be addressed in more relevant preclinical models of digestive cancers, in small and large animals before fully and successfully translating this technology for clinic use. Ultimately, a clear evidence of the correlation between the enhanced intratumoral concentrations of therapeutics and the increased therapeutic response of tumors have to be provided in clinical trials.

Advances and prospects of ultrasound targeted drug delivery systems using biomaterial-modified micro/nanobubbles for tumor therapy

The incidence of malignant tumors is rising rapidly and tends to be in the younger, which has been one of the most important factors endangering the safety of human life. Ultrasound micro/nanobubbles, as a noninvasive and highly specific antitumor strategy, can reach and destroy tumor tissue through their effects of cavitation and acoustic perforation under the guidance of ultrasound. Meanwhile, micro/nanobubbles are now used as a novel drug carrier, releasing drugs at a target region, especially on the prospects of biomaterial-modified micro/nanobubbles as a dual modality for drug delivery and therapeutic monitoring. and successful evaluation of the sonoporation mechanism(s), ultrasound parameters, drug type and dose will need to be addressed before translating this technology for clinical use. Therefore, this paper collects the literature on the experimental and clinical studies of ultrasound biomaterial-modified micro/nanobubbles therapy in vitro and in vivo in recent years.

Effects of moxibustion on Treg cells in sarcoma microenvironment

OBJECTIVE

To investigate the therapeutic effect of moxibustion on sarcomas from mesenchymal tissues, which have a low response rate to chemotherapy and radiotherapy.

METHODS

S180 sarcoma cell line was inoculated in C57BL/6 mice to form transplanted tumor. Moxibustion therapy was directly applied at the transplanted tumor sites, at a distance of 3.0 cm, 10 min per session, till skin temperature reached 45 °C, once a day, for 14 consecutive days of intervention. After the mice were killed, serum was collected and used to detect concentrations of interleukin-10 (IL-10), transforming growth factor-β1 (TGF-β1), IL-4 and interferon-γ (IFN-γ) by Luminex liquid suspension chip. The numbers of Treg⁺ T cells and CD4⁺CD25⁺Forkhead Box P3 (Foxp3)⁺ T cells were detected by flow cytometry. Fluorescence in situ hybridization was used to analyze the changes of CD4, CD8, Foxp3 and TGF-β1 in the tumor microenvironment (TME).

RESULTS

Weight of S180 transplanted tumor in the control group was (2.03 ± 0.54) g, and that in the moxibustion group was (1.27 ± 0.29) g, which was statistically different (P = 0.023). The mean value of Foxp3⁺ T cells in the normal group was 2.01%, which increased to 3.63% after the formation of transplanted tumor, and decreased to 1.48% after moxibustion treatment. The moxibustion group also had reduced numbers of CD4⁺CD25⁺Foxp3⁺ T cells in the spleen of mice with transplanted tumor. The concentrations of IL-10, TGF-β1 and IL-4 decreased in the serum of mice with transplanted tumor, while the concentration of IFN-γ increased. Moxibustion was associated with downregulation in expression of Foxp3, IL-10 and TGF-β1 genes in the transplanted tumor, and increases in the gene expression of CD4⁺ T cells and CD8⁺ T cells in the TME.

CONCLUSION

Moxibustion may have therapeutic effects on sarcomas by reducing the number of Treg cells in the blood and controlling the infiltration of Treg cells in the TME.

Ultrasound cavitation enhanced chemotherapy: In vivo research and clinical application

IMPACT STATEMENT

The novelty of this research is that we used ultrasound cavitation to enhance the effects of chemotherapy in the subcutaneous and orthotopic hepatic carcinomas in nude mice. Case reports of the effects of the targeting ultrasound cavitation and chemotherapy on malignant tumors in clinical patients were also examined. We found that low-frequency ultrasound cavitation combined with chemotherapy is effective in the inhibition of tumor growth to some extent.

Advances in low-frequency ultrasound combined with microbubbles in targeted tumor therapy

The development of low-frequency ultrasound imaging technology and the improvement of ultrasound contrast agent production technology mean that they play an increasingly important role in tumor therapy. The interaction between ultrasound and microbubbles and their biological effects can transfer and release microbubbles carrying genes and drugs to target tissues, mediate the apoptosis of tumor cells, and block the embolization of tumor microvasculature. With the optimization of ultrasound parameters, the development of targeted microbubbles, and the emergence of various composite probes with both diagnostic and therapeutic functions, low-frequency ultrasound combined with microbubble contrast agents will bring new hope for clinical tumor treatment.

Effect of docetaxel-loaded lipid microbubble in combination with ultrasound-triggered microbubble destruction on the growth of a gastric cancer cell line

Although gastric cancer therapy has been improved, more efficient treatment strategies still need to be developed. In the present study, a docetaxel (DOC)-loaded lipid microbubble (DLLD) was prepared and the effect of DLLD combined with ultrasound-triggered microbubble destruction (UTMD) on the growth of a gastric cancer cell line was investigated. The following four groups were included in the present study: Control, DOC, DLLD and DLLD plus UTMD. The determined entrapment efficiency of DLLD is 76±3.5%. The present study demonstrated that treatment with DLLD plus UTMD could significantly inhibit the growth of the cultured gastric cancer cell line BGC-823 via arresting the cell cycle in G₂/M phase, inhibiting cell DNA synthesis, promoting cell apoptosis and disrupting mitochondrial membrane potential, as compared with treatment with DOC or DLLD alone. Furthermore, the expression of p53, p21 and Bax were identified to be significantly upregulated, while that of Bcl-2 was significantly downregulated in the DLLD plus UTMD group. Therefore, treatment with DLLD plus UTMD was more efficient in inhibiting cell proliferation and inducing cell apoptosis in the gastric cancer cell line, when compared with treatment with DOC or DLLD alone, suggesting that DLLD plus UTMD could serve as a promising strategy for the treatment of gastric cancer.