In vivo evaluation of a monodisperse solid-in-oil-in-water miriplatin/ lipiodol emulsion in transcatheter arterial chemoembolization using a rabbit VX2 tumor model

An experimental study on the diagnostic advantage of dual-energy computed tomography over single-energy scan to evaluate the treatment effect following transcatheter arterial chemoembolization

OBJECTIVES

We assessed the diagnostic advantage of dual-energy computed tomography (DECT) over single-energy computed tomography (SECT) to evaluate lipiodol accumulation in target lesions following transcatheter arterial chemoembolization (TACE).

METHODS

TACE was performed in 10 rabbits in whom the VX2 tumor was implanted in their left liver lobes. The miriplatin-lipiodol mixture was injected into the common hepatic artery. All rabbits were sacrificed 2 days after TACE, and the liver was harvested. CT was performed using both single-energy and dual-energy scan modes. The specimen was stained with Oil Red O to evaluate lipiodol accumulation; this was considered the reference standard. Mutual information (MI) was used to evaluate the significance of radiological-pathological correlation. Estimated iodine content values on iodine material density images were compared with actual values obtained using mass spectroscopy.

RESULTS

Mean MI values were 0.69, 0.32, 0.83, 0.72, 0.65, and 0.58 for single-energy scan; iodine density images; and virtual monoenergetic images for energy levels of 40, 60, 80, and 100 keV, respectively. The MI value of the monochromatic image (40 keV) was the highest among all sequences. However, this was not significant compared with the single-energy scan (p = 0.81). A significant correlation was observed between the estimated and actual values of iodine content (Pearson's product moment coefficient = 0.70, p = 0.023).

CONCLUSION

More accurate and quantitative lipiodol evaluation in targeted tumors after TACE can be achieved by applying DECT rather than SECT.

Miriplatin-loaded liposome, as a novel mitophagy inducer, suppresses pancreatic cancer proliferation through blocking POLG and TFAM-mediated mtDNA replication

Pancreatic cancer is a more aggressive and refractory malignancy. Resistance and toxicity limit drug efficacy. Herein, we report a lower toxic and higher effective miriplatin (MPt)-loaded liposome, LMPt, exhibiting totally different anti-cancer mechanism from previously reported platinum agents. Both in gemcitabine (GEM)-resistant/sensitive (GEM-R/S) pancreatic cancer cells, LMPt exhibits prominent anti-cancer activity, led by faster cellular entry-induced larger accumulation of MPt. The level of caveolin-1 (Cav-1) determines entry rate and switch of entry pathways of LMPt, indicating a novel role of Cav-1 in nanoparticle entry. After endosome-lysosome processing, in unchanged metabolite, MPt is released and targets mitochondria to enhance binding of mitochondria protease LONP1 with POLG and TFAM, to degrade POLG and TFAM. Then, via PINK1-Parkin axis, mitophagy is induced by POLG and TFAM degradation-initiated mitochondrial DNA (mtDNA) replication blocking. Additionally, POLG and TFAM are identified as novel prognostic markers of pancreatic cancer, and mtDNA replication-induced mitophagy blocking mediates their pro-cancer activity. Our findings reveal that the target of this liposomal platinum agent is mitochondria but not DNA (target of most platinum agents), and totally distinct mechanism of MPt and other formulations of MPt. Self-assembly offers LMPt special efficacy and mechanisms. Prominent action and characteristic mechanism make LMPt a promising cancer candidate.

Enhanced binding of β-catenin and β-TrCP mediates LMPt's anti-CSCs activity in colorectal cancer

Cancer stem cells (CSCs), a subpopulation of tumor cells with the features of self-renewal, tumor initiation, and insensitivity to common physical and chemical agents, are the key to cancer relapses, metastasis, and resistance. Accessible CSCs inhibitory strategies are primarily based on small molecule drugs, yet toxicity limits their application. Here, we report a liposome loaded with low toxicity and high effectiveness of miriplatin, lipo-miriplatin (LMPt) with high miriplatin loading, and robust stability, exhibiting a superior inhibitory effect on CSCs and non-CSCs. LMPt predominantly inhibits the survival of oxaliplatin-resistant (OXA-resistant) cells composed of CSCs. Furthermore, LMPt directly blocks stemness features of self-renewal, tumor initiation, unlimited proliferation, metastasis, and insensitivity. In mechanistic exploration, RNA sequencing (RNA-seq) revealed that LMPt downregulates the levels of pro-stemness proteins and that the β-catenin-mediated stemness pathway is enriched. Further research shows that either in adherent cells or 3D-spheres, the β-catenin-OCT4/NANOG axis, the vital pathway to maintain stemness, is depressed by LMPt. The consecutive activation of the β-catenin pathway induced by mutant β-catenin (S33Y) and OCT4/NANOG overexpression restores LMPt's anti-CSCs effect, elucidating the key role of the β-catenin-OCT4/NANOG axis. Further studies revealed that the strengthened binding of β-catenin and β-TrCP initiates ubiquitination and degradation of β-catenin induced by LMPt. In addition,the Apc^Min/+transgenicmouse model, in which colon tumors are spontaneously formed, demonstrates LMPt's potent anti-non-CSCs activity in vivo.

Delineation of the healthy rabbit liver by immunohistochemistry - A technical note

Liver diseases pose a big global health problem and liver failure may result from viral infection, overnutrition or tumors. Studying pathologic liver tissue demands for accurate and specific histological stainings and immunohistochemical labellings, including chromogenic and fluorescent approaches. Moreover, a reliable set of healthy liver stainings and labellings are required, to provide a baseline or reference for the pathological situation. Here, we used the liver tissue of a healthy rabbit and compared different histological key steps, such as paraffin embedding after formalin fixation versus cryopreservation; or an antigen retrieval (AR) step in processing paraffin sections versus the same procedure without AR; or chromogenic with fluorescent detection system, respectively. Moreover, we provide images of serial sections, where we stained the same morphological structure with different markers, including collagen I, collagen III, fibronectin, α-SMA, elastin, protease-activated receptor-2 (PAR-2) which is an inflammation-related marker, ki67 for proliferating cells, and orcein (as negative control for pathological aberrations like Wilson disease). Differences between conditions were quantitatively assessed by measuring the colour intensity. Generally, we observed that cryosections exhibited a stronger signal intensity in immunohistochemically labelled sections than in paraffin sections; however, the strong staining got slurred, which sometimes hampered proper identification of morphological structures at higher magnifications. Moreover, there was a clear increase in signal intensity for paraffin sections when an AR step was performed compared to condition without AR. Results for mouse isotype staining as a negative control clearly supported those findings. Different stainings of the portal triad, the central vein and the bile ducts revealed a clear-cut distribution of extracellular matrix components, with prominent fibronectin and elastin around the lumen of the central vein as well as a patchy PAR-2 expression. As for the bile ducts, complete absence of α-SMA and PAR-2 was found at the margins, however, collagen I expression and elastin were positive and showed a strong signal. Like this, we provide useful and valuable reference images for researchers using the rabbit liver model. It may help to decide which of the immunohistochemical protocols are valuable to reach a certain aim and which protocols lead to the best visualization of the target structure.

Solid-in-Oil-in-Water Emulsion: An Innovative Paradigm to Improve Drug Stability and Biological Activity

Abstract

An emulsion is a biphasic dosage form comprising of dispersed phase containing droplets that are uniformly distributed into a surrounding liquid which forms the continuous phase. An emulsifier is added at the interface of two immiscible liquids to stabilize the thermodynamically unstable emulsion. Various types of emulsions such as water-in-oil (w-o), oil-in-water (o-w), microemulsions, and multiple emulsions are used for delivering certain drugs in the body. Water (aqueous) phase is commonly used for encapsulating proteins and several other drugs in water-in-oil-in-water (w-o-w) emulsion technique. But this method has posed certain problems such as decreased stability, burst release, and low entrapment efficiency. Thus, a novel “solid-in-oil-in-water” (s-o-w) emulsion system was developed for formulating certain drugs, probiotics, proteins, antibodies, and tannins to overcome these issues. In this method, the active ingredient is encapsulated as a solid and added to an oil phase, which formed a solid-oil dispersion. This dispersion was then mixed with water to form a continuous phase for enhancing the drug absorption. This article focuses on the various studies done to investigate the effectiveness of formulations prepared as solid-oil-water emulsions in comparison to conventional water-oil-water emulsions. A summary of the results obtained in each study is presented in this article. The s-o-w emulsion technique may become beneficial in near future as it has shown to improve the stability and efficacy of the entrapped active ingredient.

Graphical abstract