A novel gemcitabine derivative-loaded liposome with great pancreas-targeting ability

Effects of phospholipid type and particle size on lipid nanoparticle distribution in vivo and in pancreatic islets

Lipid nanoparticles (LNPs) have recently been used as nanocarriers in drug delivery systems for nucleic acid drugs. Their practical applications are currently primarily limited to the liver and specific organs. However, altering the type and composition ratio of phospholipids improves their distribution in organs other than the liver, such as the spleen and lungs. This study aimed to elucidate the effects of LNP components and particle size on in vivo distribution through systemic circulation to pancreatic islets to achieve better targeting of islets, which are a fundamental therapeutic target for diabetes. Fluorescence-labeled LNPs were prepared using three phospholipids: 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), with particle sizes of 30-160 nm (diameter) using a microfluidic device. Baffled-structured iLiNP devices with adjusted flow-rate ratios and total flow rates were used. After the intravenous administration of LNPs to C57BL/6 J mice, the distribution of each LNP type to the major organs, including the pancreas and pancreatic islets, was compared using ex vivo fluorescence imaging and observation of pancreatic tissue sections. DSPC-LNPs- and DOPE-LNPs showed the highest distribution in the spleen and liver, respectively. In contrast, the DOPC-LNPs showed the highest distribution in the pancreas and the lowest distribution in the liver and spleen. In addition, smaller particles showed better distribution throughout the pancreas. The most significant LNP distribution in the islets was observed for DOPC-LNPs with a particle size of 160 nm. Furthermore, larger LNPs tended to be distributed in the islets, whereas smaller LNPs tended to be distributed in the exocrine glands. DOPC-LNPs were distributed in the islets at all cholesterol concentrations, with a high distribution observed at >40% cholesterol and > 3% PEG and the distribution was higher at 24 h than at 4 h. Thus, LNP composition and particle size significantly affected islet distribution characteristics, indicating that DOPC-LNPs may be a drug delivery system for effectively targeting the pancreas and islets.

Marine sourced tripeptide SRP and its sustained-release formulation SRP-PLGA-MS exhibiting antihypertensive effect in spontaneously hypertensive rats and HUVECs

Biopeptides from Sipunculus nudus were reported with good ACE inhibitory activity, and the tripeptide SRP was one with the highest ACE inhibition rate. However, the disadvantage of short half-life limited the development of peptide drugs. Moreover, the distinct mechanism of the peptide inhibiting ACE remained unknown. Thus, in this study, a sustained release formulation of SRP-PLGA-MS was designed and prepared. Its long-lasting antihypertensive effect as well as improvement of vascular pathomorphology was verified in spontaneously hypertensive rat (SHR). In addition, the anti-oxidant activity of SRP in human umbilical vein endothelial cells (HUVECs) was evaluated. The results showed that SRP inhibited the production of ROS and NO, which involve the NADPH oxidase, and Keap1/Nrf2 signaling pathway. This study demonstrated that SRP-PLGA-MS had the potential to develop sustained-release drugs for hypertension treatment.

Inflammation and Acinar Cell Dual-Targeting Nanomedicines for Synergistic Treatment of Acute Pancreatitis via Ca2+ Homeostasis Regulation and Pancreas Autodigestion Inhibition

Severe acute pancreatitis (AP) is a life-threatening pancreatic inflammatory disease with a high mortality rate (∼40%). Existing pharmaceutical therapies in development or in clinical trials showed insufficient treatment efficacy due to their single molecular therapeutic target, poor water solubility, short half-life, limited pancreas-targeting specificity, etc. Herein, acid-responsive hollow mesoporous Prussian blue nanoparticles wrapped with neutrophil membranes and surface modified with the N,N-dimethyl-1,3-propanediamine moiety were developed for codelivering membrane-permeable calcium chelator BAPTA-AM (BA) and trypsin activity inhibitor gabexate mesylate (Ga). In the AP mouse model, the formulation exhibited efficient recruitment at the inflammatory endothelium, trans-endothelial migration, and precise acinar cell targeting, resulting in rapid pancreatic localization and higher accumulation. A single low dose of the formulation (BA: 200 μg kg-1, Ga: 0.75 mg kg-1) significantly reduced pancreas function indicators to close to normal levels at 24 h, effectively restored the cell redox status, reduced apoptotic cell proportion, and blocked the systemic inflammatory amplified cascade, resulting in a dramatic increase in the survival rate from 58.3 to even 100%. Mechanistically, the formulation inhibited endoplasmic reticulum stress (IRE1/XBP1 and ATF4/CHOP axis) and restored impaired autophagy (Beclin-1/p62/LC3 axis), thereby preserving dying acinar cells and restoring the cellular "health status". This formulation provides an upstream therapeutic strategy with clinical translation prospects for AP management through synergistic ion homeostasis regulation and pancreatic autodigestion inhibition.

Enzymatic Synthesis of Aptamer-Polynucleotide Nanoparticles with High Anticancer Drug Loading for Targeted Delivery

We report a targeted prodrug delivery platform that can deliver a cytostatic nucleobase analog with high drug loading. We chose fluorouracil (5FU), a drug used to treat various cancers, whose active metabolite 5-fluorodeoxyuridine monophosphate (5-FdUMP) is the antineoplastic agent. We use terminal deoxynucleotidyl transferase (TdT) to polymerize 5-fluorodeoxyuridine triphosphate (5-FdUTP) onto the 3'-end of an aptamer. We find that (i) addition of hydrophobic, unnatural nucleotides at the 3'-end of the 5-FdU polynucleotide by TdT leads to their spontaneous self-assembly into nuclease resistant micelles, (ii) aptamers presented on the micelle corona retain specificity for their cognate receptor on tumor cells, and (iii) the micelles deliver 5FU to tumor cells and exhibit greater cytotoxicity than the free drug. The modular design of our platform, consisting of a targeting moiety, a polynucleotide drug, and a self-assembly domain, can be adapted to encompass a range of polymerizable therapeutic nucleotides and targeting units.

Gemcitabine effects on tumor microenvironment of pancreatic ductal adenocarcinoma: Special focus on resistance mechanisms and metronomic therapies

Pancreatic ductal adenocarcinoma (PDAC) is considered one of the deadliest malignancies, with dismal survival rates and extremely prevalent chemoresistance. Gemcitabine is one of the primary treatments used in treating PDACs, but its benefits are limited due to chemoresistance, which could be attributed to interactions between the tumor microenvironment (TME) and intracellular processes. In preclinical models, certain schedules of administration of gemcitabine modulate the TME in a manner that does not promote resistance. Metronomic therapy constitutes a promising strategy to overcome some barriers associated with current PDAC treatments. This review will focus on gemcitabine's mechanism in treating PDAC, combination therapies, gemcitabine's interactions with the TME, and gemcitabine in metronomic therapies.

A fast-acting brain-targeted nano-delivery system with ultra-simple structure for brain emergency poisoning rescue

Treatment for acute brain conditions remains a major challenge owing to the unavailability of antidotes, especially for organophosphorus compounds, exposure to which leads to rapid death. Despite recent advances in brain-targeted nano delivery systems (BTNDS), the traditional ones which have been developed will likely not lead to the quick release of an antidote, which is essential to counteract fast neurotoxic effects. Herein, we present a BTNDS using thermosensitive liposomes, without the need for functionalization, to obtain a platform for brain-targeted delivery, which has a simple structure and thus can be easily synthesized and scaled-up. The brain-targeting effect of BTNDS was amplified by phospholipase A2 (PLA2), an inflammatory biomarker. The combination of PLA2 and BTNDS significantly improved brain targeting, leading to an excellent emergency rescue effect - 83- and 4.8-fold better cerebral AChE reactivation response and survival time, respectively. These findings provide a promising strategy to generate a facile, druggable, and effective BTNDS.

Novel 5-Fluorouracil Carbonate-Loaded Liposome: Preparation, In Vitro, and In Vivo Evaluation as an Antitumor Agent

5-Fluorouracil (5-FU) is a chemotherapeutic drug against many types of cancers, especially colorectal cancer. However, its short plasma half-life and serious adverse reactions limit its wide clinical applications. To overcome these shortcomings, a novel lipophilic 5-FU carbonate [XL-01, (5-fluoro-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl) methyl tetradecyl carbonate] was designed, synthesized, and encapsulated into liposome (LipoXL-01) by a thin-film dispersion method through formulation screening and optimization. LipoXL-01 was characterized by a particle size of around 100 nm, polydispersity index of 0.200, ζ-potential value of -41 mV, encapsulation efficiency of 93.9%, and drug-loading efficiency of 11.6%. The cellular uptake of LipoXL-01 was increased in a concentration-dependent manner on HCT15 cells. LipoXL-01 could enhance the induction of cell apoptosis and the inhibition of cell migration and arrest the ability of the cell cycle at the S-phase on HCT15 cells better than 5-FU. Additionally, LipoXL-01 exhibited a slow drug release profile with a cumulative release rate of 12% in 8 h. The results of pharmacokinetic and biodistribution studies revealed that LipoXL-01 had a long plasma half-life (7.21 h) and a high tumor accumulation (733 nmol/g at 8 h). The in vivo antitumor effect study also showed that LipoXL-01 had more potent efficacy than 5-FU (65 vs 48% of the tumor-inhibition rate). Simultaneously, negligible systemic toxicity was observed via analyzing the body weight as well as hematological and pathological parameters in the tested mice. The current study suggested that LipoXL-01 might be a promising nanocandidate for chemotherapy of colorectal cancer.

Preparation and pharmacokinetics in vivo of linarin solid dispersion and liposome

Objective

The current investigation aimed to determine the appropriate dosage form by comparing solid dispersion and liposome to achieve the purpose of improving the solubility and bioavailability of linarin.

Methods

Linarin solid dispersion (LSD) and linarin liposome (LL) were developed via the solvent method and the thin film hydration method respectively. The Transwell chamber model of Caco-2 cells was established to evaluate the absorption of drug. The pharmacokinetics of linarin, LSD and LL in rats after ig administration were carried out by high performance liquid chromatography (HPLC) method.

Results

The solubility of LSD and LL was severally 3.29 times and 3.09 times than that of linarin. The permeation coefficients of LSD and LL were greater than 10⁻⁶, indicating that the absorption of LSD and LL were both better than linarin. The bioavailability of the LSD was 3.363 times higher than that of linarin, and the bioavailability of LL was 0.9886 times higher than that of linarin.

Conclusion

The linarin was more suitable for making solid dispersion to enhance its solubility and bioavailability.

Nanocarriers targeting the diseases of the pancreas

Diseases of the pancreas include acute and chronic pancreatitis, exocrine pancreatic insufficiency, diabetes and pancreatic cancer. These pathologies can be difficult to treat due to the innate properties of the pancreas, its structure and localization. The need for effective targeting of the pancreatic tissue by means of nanoparticles delivering therapeutics is a major focus area covered and discussed in this review. Most common diseases of the pancreas do not have specific and direct medical treatment option, and existing treatment options are generally aimed at relieving symptoms. Diabetes has different treatment options for different subtypes based on insulin having stability problems and requiring injections reducing patient compliance. Pancreatic cancer progresses silently and can only be diagnosed in advanced stages. Therefore, survival rate of patients is very low. Gemcitabine and FOLFIRINOX treatment regimens, the most commonly used clinical standard treatments, are generally insufficient due to the chemoresistance that develops in cancer cells and also various side effects. Therefore new treatment options for pancreatic cancer are also under focus. Overcoming drug resistance and pancreatic targeting can be achieved with active and passive targeting methods, and a more effective and safer treatment regimen can be provided at lower drug doses. This review covers the current literature and clinical trials concerning pancreatic drug delivery systems in the nanoscale focusing on the challenges and opportunities provided by these smart delivery systems.

One-shot dual gene editing for drug-resistant pancreatic cancer therapy

It is challenging to diagnose patients with pancreatic ductal adenocarcinoma (PDAC) early on, and their treatment is often complex. Gemcitabine (GEM) is the first-line treatment for PDAC, but its efficacy is limited in most patients due to the GEM resistance from KRAS and P53 gene mutations. We describe the correction of a double gene mutation and therapeutic effect for the GEM resistant PDAC. Bio-available nanoliposomes (NL) possessing Cas9-ribonucleoproteins and adenine-base editors were developed to conduct KRAS and P53 mutation gene editing directly. NLs were conjugated with EGFR antibodies to tumor-specific delivery, and the anti-cancer effect was verified in vitro and in vivo Model. Our GEM-combinatorial therapeutic strategies using double gene editing systems with one-shot may be a potent therapy for PDAC, overcoming chemoresistance.

The evolution of nucleosidic analogues: self-assembly of prodrugs into nanoparticles for cancer drug delivery

Nucleoside and nucleotide analogs are essential tools in our limited arsenal in the fight against cancer. However, these structures face severe drawbacks such as rapid plasma degradation or hydrophilicity, limiting their clinical application. Here, different aspects of nucleoside and nucleotide analogs have been exposed, while providing their shortcomings. Aiming to improve their fate in the body and combating their drawbacks, two different approaches have been discussed, the prodrug and nanocarrier technologies. Finally, a novel approach called "PUFAylation" based on both the prodrug and nanocarrier technologies has been introduced, promising to be the supreme method to create a novel nucleoside or nucleotide analog based formulation, with enhanced efficacy and highly reduced toxicity.

Engineering Extracellular Vesicles to Target Pancreatic Tissue In Vivo

Extracellular vesicles (EVs) are naturally released, cell-derived vesicles that mediate intracellular communication, in part, by transferring genetic information and, thus, have the potential to be modified for use as a therapeutic gene or drug delivery vehicle. Advances in EV engineering suggest that directed delivery can be accomplished via surface alterations. Here we assess enriched delivery of engineered EVs displaying an organ targeting peptide specific to the pancreas. We first characterized the size, morphology, and surface markers of engineered EVs that were decorated with a recombinant protein specific to pancreatic β-cells. This β-cell-specific recombinant protein consists of the peptide p88 fused to the EV-binding domain of lactadherin (C1C2). These engineered EVs, p88-EVs, specifically bound to pancreatic β-cells in culture and transferred encapsulated plasmid DNA (pDNA) as early as in 10 min suggesting that the internalization of peptide-bearing EVs is a rapid process. Biodistribution of p88-EVs administrated intravenously into mice showed an altered pattern of EV localization and improved DNA delivery to the pancreas relative to control EVs, as well as an accumulation of targeting EVs to the pancreas using luciferase activity as a readout. These findings demonstrate that systemic administration of engineered EVs can efficiently deliver their cargo as gene carriers to targeted organs in live animals.

Gemcitabine Lipid Prodrugs: The Key Role of the Lipid Moiety on the Self-Assembly into Nanoparticles

A small library of amphiphilic prodrugs has been synthesized by conjugation of gemcitabine (Gem) (a hydrophilic nucleoside analogue) to a series of lipid moieties and investigated for their capacity to spontaneously self-assemble into nanosized objects by simple nanoprecipitation. Four of these conjugates formed stable nanoparticles (NPs), while with the others, immediate aggregation occurred, whatever the tested experimental conditions. Whether such capacity could have been predicted based on the prodrug physicochemical features was a matter of question. Among various parameters, the hydrophilic-lipophilic balance (HLB) value seemed to hold a predictive character. Indeed, we identified a threshold value which well correlated with the tendency (or not) of the synthesized prodrugs to form stable nanoparticles. Such a hypothesis was further confirmed by broadening the analysis to Gem and other nucleoside prodrugs already described in the literature. We also observed that, in the case of Gem prodrugs, the lipid moiety affected not only the colloidal properties but also the in vitro anticancer efficacy of the resulting nanoparticles. Overall, this study provides a useful demonstration of the predictive potential of the HLB value for lipid prodrug NP formulation and highlights the need of their opportune in vitro screening, as optimal drug loading does not always translate in an efficient biological activity.

Recent Advances in Lipid-Based Nanosystems for Gemcitabine and Gemcitabine-Combination Therapy

The anti-metabolite drug gemcitabine is widely used for the treatment of a variety of cancers. At present, gemcitabine is administered as a hydrochloride salt that is delivered by slow intravenous injection in cycles of three or four weeks. Although regarded as a 'front-line' chemotherapeutic agent, its efficacy is hampered by poor target cell specificity, sub-optimal cellular uptake, rapid clearance from circulation, the development of chemoresistance, and undesirable side-effects. The use of organic, inorganic, and metal-based nanoparticles as delivery agents presents an opportunity to overcome these limitations and safely harness optimal drug efficacy and enhance their therapeutic indices. Among the many and varied nano delivery agents explored, the greatest body of knowledge has been generated in the field of lipid-mediated delivery. We review here the liposomes, niosomes, solid lipid nanoparticles, nanostructured lipid carriers, exosomes, lipid-polymer hybrids, and other novel lipid-based agents that have been developed within the past six years for the delivery of gemcitabine and its co-drugs.

Enhancement of Antitumor Efficacy of Paclitaxel-Loaded PEGylated Liposomes by N,N-Dimethyl Tertiary Amino Moiety in Pancreatic Cancer

Introduction

Pancreatic cancer, or pancreatic duct adenocarcinoma (PDAC), remains one of the most lethal cancers and features insidious onset, highly aggressive behavior and early distant metastasis. The dense fibrotic stroma surrounding tumor cells is thought to be a shield to resist the permeation of chemotherapy drugs in the treatment of PDAC. Thus, we synthesized a pancreas-targeting paclitaxel-loaded PEGylated liposome and investigated its antitumor efficacy in the patient-derived orthotopic xenograft (PDOX) nude mouse models of PDAC.

Methods

The PTX-loaded PEGylated liposomes were prepared by film dispersion-ultrasonic method and modified by an N,N-dimethyl tertiary amino residue. Morphology characteristics of the PTX-loaded liposomes were observed by transmission electron microscope (TEM). The PDOX models of PDAC were established by orthotopic implantation and imaged by a micro positron emission tomography/computed tomography (PET/CT) imaging system. The in vivo distribution and antitumor study were then carried out to observe the pancreas-targeting accumulation and the antitumor efficacy of the proposed PTX liposomes.

Results

PTX loaded well into both modified (PTX-Lip2N) and unmodified (PTX-Lip) PEGylated liposomes with spherical shapes and suitable parameters for the endocytosis process. The PDOX nude mouse models were successfully created in which high ¹⁸F-FDG intaking regions were observed by micro-PET/CT. In addition to higher cellular uptakes of PTX-Lip2N by the BxPC-3 cells, the proposed nanoparticle had a notable penetrating ability towards PDAC tumor tissues, and consequently, the antitumor ability of PTX-Lip2N was significantly superior to the unmodified PTX-Lip in vivo PDOX models and even more effective than nab-PTX in restraining tumor growth.

Conclusion

The modified pancreas-targeting PTX-loaded PEGylated liposomes provide a promising platform for the treatment of pancreatic cancer.