Preparation, characterization, pharmacokinetics and anticancer effects of PEGylated β-elemene liposomes

Objective:This study aimed to develop a new polyethylene glycol(PEG)ylatedβ-elemene liposome(PEG-Lipo-β-E)and evaluate its characterization,pharmacokinetics,antitumor effects and safety in vitro and in vivo.Methods:The liposomes were prepared by ethanol injection and high-pressure micro-jet homogenization.Characterization of the liposomes was conducted,and drug content,entrapment efficiency(EE),in vitro release and stability were studied by ultra-fast liquid chromatography(UFLC)and a liquid surface method.Blood was drawn from rats to establish the pharmacokinetic parameters.The anticancer effect was evaluated in a KU-19-19 bladder cancer xenograft model.Histological analyses were performed to evaluate safety.Results:The PEG-Lipo-β-E showed good stability and was characterized as 83.31±0.181 nm in size,0.279±0.004 in polydispersity index(PDI),-21.4±1.06 mV in zeta potential,6.65±0.02 in pH,5.024±0.107 mg/mL inβ-elemene(β-E)content,and 95.53±1.712%in average EE.The Fourier transform infrared spectroscopy(FTIR)and differential scanning calorimetry(DSC)indicated the formation of PEG-Lipo-β-E.Compared to elemene injection,PEG-Lipo-β-E demonstrated a 1.75-fold decrease in clearance,a 1.62-fold increase in half-life,and a 1.76-fold increase in area under the concentration-time curves(AUCs)from 0 hour to 1.5 hours(P<0.05).PEG-Lipo-β-E also showed an enhanced anticancer effect in vivo.Histological analyses showed that there was no evidence of toxicity to the heart,kidney,liver,lung or spleen.Conclusions:The present study demonstrates PEG-Lipo-β-E as a new formulation with ease of preparation,high EE,good stability,improved bioavailability and antitumor effects.

PCDH17 increases the sensitivity of colorectal cancer to 5-fluorouracil treatment by inducing apoptosis and autophagic cell death

5-Fluorouracil(5-FU)is known as a first-line chemotherapeutic agent against colorectal cancer(CRC),but drug resistance occurs frequently and significantly limits its clinical success.Our previous study showed that the protocadherin 17(PCDH17)gene was frequently methylated and functioned as a tumor suppressor in CRC.However,the relationship between PCDH17 and 5-FU resistance in CRC remains unclear.Here,we revealed that PCDH17 was more highly expressed in 5-FU-sensitive CRC tissues than in 5-FU-resistant CRC tissues,and high expression of PCDH17 was correlated with high BECN1 expression.Moreover,this expression profile contributed to superior prognosis and increased survival in CRC patients.Restoring PCDH17 expression augmented the 5-FU sensitivity of CRC in vitro and in vivo by promoting apoptosis and autophagic cell death.Furthermore,autophagy played a dominant role in PCDH17-induced cell death,as an autophagy inhibitor blocked cell death to a greater extent than the pancaspase inhibitor Z-VAD-FMK.PCDH17 inhibition by siRNA decreased the autophagy response and 5-FU sensitivity.Mechanistically,we showed that c-Jun NH2-terminal kinase(JNK)activation was a key determinant in PCDH17-induced autophagy.The compound SP600125,an inhibitor of JNK,suppressed autophagy and 5-FU-induced cell death in PCDH17-reexpressing CRC cells.Taken together,our findings suggest for the first time that PCDH17 increases the sensitivity of CRC to 5-FU treatment by inducing apoptosis and JNK-dependent autophagic cell death.PCDH17 may be a potential prognostic marker for predicting 5-FU sensitivity in CRC patients.