Yiguang Jin

fMiRNA-192 and miRNA-204 Directly Suppress lncRNA HOTTIP and Interrupt GLS1-Mediated Glutaminolysis in Hepatocellular Carcinoma

Accumulated evidence demonstrated that long non-coding RNAs (lncRNAs) play a pivotal role in tumorigenesis. However, it is still largely unknown how these lncRNAs were regulated by small ncRNAs, such as microRNAs (miRNAs), at the post-transcriptional level. We here use lncRNA HOTTIP as an example to study how miRNAs impact lncRNAs expression and its biological significance in hepatocellular carcinoma (HCC). LncRNA HOTTIP is a vital oncogene in HCC, one of the deadliest cancers worldwide. In the current study, we identified miR-192 and miR-204 as two microRNAs (miRNAs) suppressing HOTTIP expression via the Argonaute 2 (AGO2)-mediated RNA interference (RNAi) pathway in HCC. Interaction between miR-192 or miR-204 and HOTTIP were further confirmed using dual luciferase reporter gene assays. Consistent with this notion, a significant negative correlation between these miRNAs and HOTTIP exists in HCC tissue specimens. Interestingly, the dysregulation of the three ncRNAs was associated with overall survival of HCC patients. In addition, the posttranscriptional silencing of HOTTIP by miR-192, miR-204 or HOTTIP siRNAs could significantly suppress viability of HCC cells. On the contrary, antagonizing endogenous miR-192 or miR-204 led to increased HOTTIP expression and stimulated cell proliferation. In vivo mouse xenograft model also support the tumor suppressor role of both miRNAs. Besides the known targets (multiple 5’ end HOX A genes, i.e. HOXA13), glutaminase (GLS1) was identified as a potential downstream target of the miR-192/-204-HOTTIP axis in HCC. Considering glutaminolysis as a crucial hallmark of cancer cells and significantly inhibited cell viability after silencingGLS1, we speculate that the miR-192/-204-HOTTIP axis may interrupt HCC glutaminolysis through GLS1 inhibition. These results elucidate that the miR-192/-204-HOTTIP axis might be an important molecular pathway during hepatic cell tumorigenesis. Our data in clinical HCC samples highlight miR-192, miR-204 and HOTTIP with prognostic and potentially therapeutic implications.

A 5-fluorouracil-loaded pH-responsive dendrimer nanocarrier for tumor targeting

A novel long-circulating and pH-responsive dendrimer nanocarrier was prepared for delivering 5-fluorouracil (5-FU) to tumors through the targeting of nanoparticles to the low pH environment of tumors. The nanocarrier, poly(2-(N,N-diethylamino)ethyl methacrylate) with methoxy-poly(ethylene glycol)-poly(amidoamine) (PPD), had a core-shell structure with 4.0 G poly(amidoamine) (PAMAM) as the core and parallel poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEA) chains and methoxy-poly(ethylene glycol) (mPEG) chains as the shell. The PDEA chain was pH-responsive, and the PEG chains led to long circulation in blood vessels to achieve tumor targeting. The sizes, drug encapsulation and release of PPD nanocarriers showed high pH-dependency due to the PDEA chains, as they were hydrophilic at pH 6.5 and hydrophobic at pH 7.4. The encapsulation efficiency of 5-FU in PPD nanocarriers was as high as 92.5% through the pH transition. The release of 5-FU from PPD nanocarriers was much faster at pH 6.5 than at pH 7.4. The 5-FU-loaded nanocarrier had a long half-life after intravenous administration in mice and showed high tumor targeting. This nanocarrier composite also showed enhanced anticancer effects. PPD is a promising nanocarrier of anticancer drugs with high encapsulation, tumor targeting and pH-responsive release in tumors.

Transdermal delivery of the in situ hydrogels of curcumin and its inclusion complexes of hydroxypropyl-β-cyclodextrin for melanoma treatment.

Curcumin (Cur) is a hydrophobic polyphenol with diverse pharmacological effects, especially for cancer treatment. However, its weak water solubility and stability was the major obstacle for the formulation research of Cur. The complexation of Cur and hydroxypropyl-β-cyclodextrin (HP-β-CD) was done by grinding. The increasing solubility of Cur was achieved due to complexation and the photochemical stability of Cur was improved. The inclusion of Cur could happen when two ends of Cur were embedded into the cavity of the HP-β-CD rings. The in situ hydrogels (ISGs) of Cur and its inclusion complexes were prepared using poloxamers 407 and 188 as the matrix. The extent of drugs in vitro release from the ISGs depended on the dissolution of drugs. Both of the ISGs had transdermal effect and cytotoxicity on B16-F10 cells. However, the effects of the ISGs containing Cur inclusion complexes were much higher than those of Cur ISGs because of the improved Cur solubility in the former. The cytotoxicity of Cur on melanoma cells was related to blocking of cellular proliferation in the G2/M stage followed by cellular apoptosis. The ISGs of Cur inclusion complexes are a promising formulation for melanoma treatment.

Ultrasound-triggered drug release and enhanced anticancer effect of doxorubicin-loaded poly(D,L-lactide-co-glycolide)-methoxy-poly(ethylene glycol) nanodroplets.

A novel ultrasound-responsive doxorubicin (DOX)-loaded nanoparticulate system was prepared in this study. The DOX-loaded polymeric micelles were first prepared using poly(D,L-lactide-co-glycolide)-methoxy-poly(ethylene glycol) (PLGA-mPEG) with a high encapsulation efficiency of 89.2%. After filling with perfluoropentane (boiling point 29 °C), the micelles were transformed into nanodroplets that were stable as a result of the PEG shell. The nanodroplets were transformed into nanobubbles at 37 °C, and little drug was released if no ultrasound was exerted. Ultrasound-triggered drug release, with pH dependency, was shown. The DOX release percentage was 9.59% at pH 6.5 (also appeared in tumor) and only 2.22% at pH 7.4 after sonicating for 0.5 min at 37 °C. The tumor inhibitory rate of Group III (DOX-loaded nanodroplets combined with ultrasound) was 84.3%, more than that of Group II (DOX-loaded nanodroplets), which was 60.4%. Moreover, the nanodroplets showed much lower toxicity than free drugs. The novel nanodroplets could be a promising anticancer drug delivery system.

Self-assembled drug delivery systems. Part 5: self-assemblies of a bolaamphiphilic prodrug containing dual zidovudine.

A bolaamphiphilic prodrug containing dual zidovudine, pentadecanedioyl dizidovudine (PDDZ), was prepared. The vesicular self-assemblies were formed in aqueous media through injecting the methanol solution of PDDZ into water. Hydrophobic interaction between lipid chains should drive molecular self-assembly. The nonionic surfactant, Tween 20, was used to increase the physical stability of self-assemblies because the surfactant micelles could prevent the assemblies from aggregating. The doping hydroxylpropylmethylcellulose (HPMC) slowed down the degradation of prodrugs due to adsorption. The self-assemblies were nanoscale with the mean particle size of 156 nm. Degradation of PDDZ was very slow in buffered solutions, but very rapid in enzyme and plasma, and the parent drug zidovudine (AZT) was the unique product. PDDZ self-assemblies showed strong anti-HIV activity on MT4 cell model. The 50% effective concentration (EC(50)) of PDDZ was 5 nM, equal to that of AZT. PDDZ was rapidly eliminated from circulation and mainly distributed into liver, spleen and testis followed by the rapid production of AZT after intravenous administration of the self-assemblies to rabbits. Macrophages in liver, spleen and testis are the reservoir of HIV so that the macrophage targeting effect of PDDZ self-assemblies would benefit to anti-HIV therapy. The self-assemblies composed of bolaamphiphilic PDDZ are a promising self-assembled drug delivery system (SADDS).

Combination anti-HIV therapy with the self-assemblies of an asymmetric bolaamphiphilic zidovudine/didanosine prodrug.

Combination anti-HIV therapy is important for AIDS treatment. A bolaamphiphilic prodrug, zidovudine-phosphoryl-deoxycholyl didanosine (ZPDD), was synthesized, combining zidovudine (AZT) and didanosine (ddI) in one molecule. As one lipid derivative of nucleosides, ZPDD showed special solubility with free soluble in chloroform and tetrahydrofuran but was slightly soluble in cyclohexane. The amphiphilicity of ZPDD was shown according to the monolayers at the air-water interface. ZPDD self-assembled to the spherical vesicles in water with 174 nm in size and -31.3 mV of zeta potential. The stability of assemblies depended on pH because the phosphoryl zidovudine group could release hydrogen ions. ZPDD was rapidly degraded to AZT in the plasma and tissues of mice. ZPDD self-assemblies had high anti-HIV activity in vitro with the half effective concentration (EC₅₀) of 5 nM. ZPDD self-assemblies may be targeting macrophages since ZPDD was found in macrophage-rich tissues in vivo and rapidly released AZT in the targeted tissues after intravenous administration to mice. The bioavailability of ZPDD was 90.5% and 30.8% for the intraperitoneal and oral administrations compared with the venous route. The self-assemblies of bolaamphiphilic prodrugs could simultaneously deliver two types of drugs to targeted tissues and would become a promising nanomedicine.

Self-assembled drug delivery systems: Part 3. In vitro/in vivo studies of the self-assembled nanoparticulates of cholesteryl acyl didanosine

Self-assembled drug delivery systems (SADDS) are defined as the self-assemblies of amphiphilic prodrugs, integrating prodrugs, molecular self-assembly and nanotechnology for drug targeting and controlled release. Cholesteryl-succinyl didanosine (CSD) and cholesteryl-adipoyl didanosine (CAD) nanoparticulate systems in water were previously prepared and optimized. In this paper, the in vitro and in vivo behavior of them was investigated. Precipitation occurred when they were mixed with acid solutions due to rapid production of hypoxanthine and subsequent disruption of supramolecular structures. They showed pH-dependent degradation and kept relatively stable in the neutral pH range. CSD is more stable than CAD due to the shorter spacer and poloxamer protection. CSD showed different degradation rates in various plasma with the descending order of rat, mouse, rabbit, dog and human. The half-life (t(1/2)) of CSD is 9 days in rat plasma, and 5.9 days in rat liver homogenates. CAD has a faster degradation than CSD though the t(1/2) in rat liver homogenates is long to 23 h. CSD nanoparticulates showed no significant anti-HIV effect in MT4 cell model because of very slow degradation. CSD nanoparticulates showed the distribution t(1/2) of 7.6 min after bolus intravenous (i.v.) administration to rats, and the site-specific distribution in liver, lung and spleen with the high t(1/2) of 10 days in liver. The factors affecting achievement of successful SADDS are discussed.

Monolayers of the lipid derivatives of isoniazid at the air/water interface and the formation of self-assembled nanostructures in water

Isoniazid (INH, isonicotinic acid hydrazide) is one of the most commonly used anti-tubercular drugs. However, resistance of Mycobacterium tuberculosis strains to anti-mycobacterial agents including INH is an increasing problem worldwide. Development of new anti-mycobacterial agents thus has attracted attention. Five lipid derivatives of INH were prepared in this study. They formed monolayers at the air/water interface, and some nanostructures with different morphologies were obtained through molecular self-assembly in water. The derivatives included one fatty acyl derivative containing a 12-C hydrocarbon-long chain (1), three fatty alcohol derivatives with a succinyl as spacer and an 8, 12 or 16-C hydrocarbon-long chain (2, 3 and 4), and one tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) derivative containing a 12-C hydrocarbon-long chain (5). The surface pressure-area isotherms depended on the volume and configuration of heads and the length of tails of derivatives. Compound 2 had a relatively large head and a short tail, easily standing uprightly at the interface. Under a certain surface pressure, the linear polar head groups of 3 could be partly squeezed out and insert into subphase because the length of heads were comparable to the one of tails. The very long tails of 4 always maintained above the interface and led to a high collapse pressure. Compound 5 possessed an extended and large head consisting of the THTT and INH groups so that the relatively short tails tilted at the interface and difficultly contact with each other. The THTT rings might be partly squeezed out and enter into air under a certain surface pressure. The self-assembly behaviours of derivatives in water depended on the molecular configuration and agreed with the corresponding monolayer behaviours. The flexible and medium-long tails (1 and 3) led to the derivatives to form nanoscale vesicles, though the short or very long tails did not (2 and 4). Interestingly, intermolecular hydrogen bonding could occur between the molecules of 5, and improve the derivative forming helical nanofibres other than vesicles. The molecular self-assembly of INHs lipid derivatives was explored in details in this study. The formation mechanisms of self-assembled nanostructures were analyzed. Various types of self-assembled nanostructures were obtained and the formation mechanisms were analyzed. The relationship between the self-assembly and the molecular configuration of amphiphilic derivatives was also revealed. The lipid derivatives of INH show promising anti-Mycobacterium action because the amphiphilic prodrugs allow for better penetration of the bacterial cells. The self-assembled nanostructures may likely be the potential self-assembled drug delivery systems for tuberculosis therapy.

Tea tree oil nanoemulsions for inhalation therapies of bacterial and fungal pneumonia.

Tea tree oil (TTO) is a natural essential oil with strong antimicrobial efficacy and little drug resistance. However, the biomedical applications of TTO are limited due to its hydrophobicity and formulation problems. Here, we prepared an inhalable TTO nanoemulsion (nanoTTO) for local therapies of bacterial and fungal pneumonia. The optimal formulation of nanoTTOs consisted of TTO/Cremophor EL/water with a mean size of 12.5nm. The nanoTTOs showed strong in vitro antimicrobial activities on Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus and Candida albicans. After inhalation to the lung, the nanoTTOs had higher anti-fungal effect than fluconazole on the fungal pneumonia rat models with reduced lung injury, highly microbial clearance, blocking of leukocyte recruitment, and decrease of pro-inflammatory mediators. In the case of rat bacterial pneumonia, the nanoTTOs showed slightly lower therapeutic efficacy than penicillin though at a much lower dose. Taken together, our results show that the inhalable nanoTTOs are promising nanomedicines for local therapies of fungal and bacterial pneumonia with no obvious adverse events.

Self-assembled drug delivery systems. Part 6: in vitro/in vivo studies of anticancer N-octadecanoyl gemcitabine nanoassemblies.

The nanoassemblies were prepared from N-octadecanoyl gemcitabine (NOG)/cholesteryl succinyl poly(ethylene glycol) 1500 (CHS-PEG(1500)) (5:1, mol/mol). They showed higher cytotoxicity than gemcitabine on HpG2 cell model. The amphiphilicity of NOG may improve permeation of prodrugs and destruction of cell membrane. The nanoassemblies were rapidly eliminated from circulation after bolus intravenous administration to healthy and tumor-bearing mice. The in vivo distribution sites of NOG were mainly liver and spleen though the distribution in tumor was not high. The non-spherical shape and high surface charge of the nanoassemblies may affect distribution. The nanoassemblies had similar anticancer efficacy to free gemcitabine solutions when the former contained about 1/3 dose of the latter in gemcitabine form. The nanoassemblies would be a promising anticancer nanomedicine.