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Aim To construct a drug delivery system of osthole loaded by exosomes. Methods Osthole could inhibit the proliferation of ovarian cancer cells by literature. SKOV3 cells were treated with 80 (µnol • L
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The complexity of tumor microenvironment brings both challenges and opportunities for targeted drug delivery. On the one hand, using the special characteristic as stimuli, we can construct a variety of responsive drug delivery systems for tumor targeting. On the other hand, the abnormal vasculature and dense extracellular matrix in solid tumor become formidable barriers to the nanoparticles delivery, which greatly reduces the drug delivery efficiency. Lots of researches focus on regulating the tumor microenvironment to make it more conducive to drug delivery. In this review, we will highlight the recent advances both in tumor microenvironment responsive nano-drug delivery systems design and tumor microenvironment regulation to improve tumor targeted delivery efficiency, and discuss the existing problems and future development.
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Objective To investigate the impact of planning parameter settings on plan quality and delivery efficiency of VMAT for nasopharyngeal carcinoma with two treatment planning systems (TPS),as references for clinic plan optimization. Methods 25 patients with nasopharyngeal carcinoma were selected and planned for SIB?VMAT treatment. The same planning aims were used in the two kinds of TPS ( TPS?1 and TPS?2). Multiple planning parameters were set for plan optimization. Dose distribution to the target volumes and organs at risk,monitor unit ( MU) and delivery time were compared. Paired t?test or one?way ANOVA was used for the data which was in accordance to normal distribution;otherwise, nonparametric Wilcoxon signed rank test or nonparametric Friedman test was used. Results More segments lead to better plan quality and less MU but longer delivery time ( Minor impact was observed when segment number was larger than 120) in TPS?1,while it had little impact on both plan quality and delivery efficiency in TPS?2. Comparing to single?arc plans,dual?arc VMAT achieved no significant benefit in plan quality but had more MU and longer delivery time in TPS?1 ( P= 0?000 ) . However, dual?arc VMAT plans had better dose distribution in TPS?2, decreased the maximum and mean dose for spinal cord in 3?9% and 13?7%respectively (P=0?000,0?000).Changing the settings of maximum or minimum dose rate did not affect the plan quality in both of the tested TPSs. Increasing the maximum or minimum dose rate reduced the delivery time but the latter increased the number of MU ( P=0?000,0?000) . Conclusions VMAT plan quality and delivery efficiency is affected significantly and differently by planning parameter settings for two TPSs. Trial test should be conducted for different TPS to determine the optimal parameter settings.